Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33990
Zushuai Xie, Zhiqing Wu, Jianhui Wu
This paper presents a comprehensive technique review for CCDD rectifier. It includes the challenges for the design of RF-to-DC rectifier and techniques for the efficiency improvement by controlling the gates and bodies of MOS in CCDD rectifier. The comparison of different techniques for efficiency improvement is concluded. The idea for novel CCDD is discussed and simple simulation result is shown in this paper. Introduction Over the past decades, low power design has attracted massive researches to push integrated system to consume as less as power with proper trade-off between parameters. Many low power and low voltage circuits have been reported [1]. However, it is still challenging to maintain these circuits working more than ten years without battery. Though integration has massively been increased driven by Moore’s law and power consumption has aggressively decreased, battery capability has not kept the pace of industry’s development. This trend has severely constrained the deployment of IoT. As the network of IoT requires massive nodes, about several millions, the battery replacement extremely increases the management cost. Figure 1. Main blocks for RF energy harvesting system. Energy harvesting technology is emerging as an excellent candidate to achieve self-sustainable nodes for IoT applications [2]. It has attracted intensive researches among academics. Although wireless energy among the free space features the minimal energy density due to the transmission loss among the above energy sources, RF energy harvesting attracts the researchers’ interests for its potential feasibility and compatibility with RF transceiver as antenna can both achieve signal receiving/transmitting and energy converting, so no extra energy converter component is required. As shown in Fig. 1, a simplified system blocks for RF energy harvesting constitutes with antenna, RF-to-DC rectifier and Power management unit (PMU). Antenna is used to receive the ambient RF energy in open air. RF-to-DC rectifier achieves to obtain the required DC energy. PMU is used to dynamically control the received energy. And high efficiency of RF-to-DC rectifier plays the most important role in RF energy harvesting system. As shown in Fig. 2, RF-to-DC rectifier can be categorized into two branches: single rectifier (Fig. 2a) and CCDD rectifier (Fig. 2b). This paper only focuses on the efficiency improvement techniques for CCDD rectifier. The rest of this paper is organized as follows. In section 2, the challenge for rectifier design will be stated. In section 3, techniques for high efficiency by controlling the gate and body of differential drive crossing coupling rectifier are reviewed. Finally, section 4 concludes this paper.
{"title":"Technique Review for Differential Drive Crossing Coupling Rectifier in RF Energy Harvester","authors":"Zushuai Xie, Zhiqing Wu, Jianhui Wu","doi":"10.12783/dteees/peems2019/33990","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33990","url":null,"abstract":"This paper presents a comprehensive technique review for CCDD rectifier. It includes the challenges for the design of RF-to-DC rectifier and techniques for the efficiency improvement by controlling the gates and bodies of MOS in CCDD rectifier. The comparison of different techniques for efficiency improvement is concluded. The idea for novel CCDD is discussed and simple simulation result is shown in this paper. Introduction Over the past decades, low power design has attracted massive researches to push integrated system to consume as less as power with proper trade-off between parameters. Many low power and low voltage circuits have been reported [1]. However, it is still challenging to maintain these circuits working more than ten years without battery. Though integration has massively been increased driven by Moore’s law and power consumption has aggressively decreased, battery capability has not kept the pace of industry’s development. This trend has severely constrained the deployment of IoT. As the network of IoT requires massive nodes, about several millions, the battery replacement extremely increases the management cost. Figure 1. Main blocks for RF energy harvesting system. Energy harvesting technology is emerging as an excellent candidate to achieve self-sustainable nodes for IoT applications [2]. It has attracted intensive researches among academics. Although wireless energy among the free space features the minimal energy density due to the transmission loss among the above energy sources, RF energy harvesting attracts the researchers’ interests for its potential feasibility and compatibility with RF transceiver as antenna can both achieve signal receiving/transmitting and energy converting, so no extra energy converter component is required. As shown in Fig. 1, a simplified system blocks for RF energy harvesting constitutes with antenna, RF-to-DC rectifier and Power management unit (PMU). Antenna is used to receive the ambient RF energy in open air. RF-to-DC rectifier achieves to obtain the required DC energy. PMU is used to dynamically control the received energy. And high efficiency of RF-to-DC rectifier plays the most important role in RF energy harvesting system. As shown in Fig. 2, RF-to-DC rectifier can be categorized into two branches: single rectifier (Fig. 2a) and CCDD rectifier (Fig. 2b). This paper only focuses on the efficiency improvement techniques for CCDD rectifier. The rest of this paper is organized as follows. In section 2, the challenge for rectifier design will be stated. In section 3, techniques for high efficiency by controlling the gate and body of differential drive crossing coupling rectifier are reviewed. Finally, section 4 concludes this paper.","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84046468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33970
L. Honghui, Liao Xiaojuan, Li Yuan
The finite element method is used to analyze the shear stress distribution of the pavement structure under vertical load and both vertical and horizontal load. The results show that the distribution coefficient of transverse force affects the distribution of shear stress with depth; The maximum shear stress increases with the increase of the lateral force coefficient, and the two have a linear relationship. When the horizontal force is considered, the shear stress of the asphalt surface layer increases and the peak value moves upward, which may cause rutting, displacement and swelling of the asphalt pavement. It is necessary to incorporate the horizontal force into the structural design index system. Introduction With the increasing of highway traffic volume and the development of heavy transportation, especially the operation of channelized traffic in high-grade highways, the rutting of asphalt pavement has become the main disease type [1] , and the main type of rutting is the fluidity rutting caused by the shear deformation of asphalt mixture [2,3] . In the summer high temperature season, the shear strength of the asphalt mixture gradually decreases with the increase of temperature. When the shear strength decreases to less than the shear stress, the asphalt mixture will produce shear deformation. Under the repeated action of the load, the wheel track will sag and both sides will rise, forming a W-shaped rut with a cross section. At the same time, displacement and swelling and washboard is also caused by the insufficient shear strength under the action of horizontal load at high temperature. Therefore, it is of great significance to optimize the design of pavement structure and reduce the occurrence of ruts to analyze the mechanics of multibrake sections such as steep road sections and toll stations considering the horizontal force and to explore the distribution law of shear stress. The Selection of Pavement Structure Parameters and the Establishment of Finite Element Model Pavement Structure Parameters Select the commonly used semi-rigid base asphalt pavement structure in China, and the material thickness and parameters are shown in Table 1. Table 1. Calculation parameters of pavement structure. Horizon Material Thicknesscm Modulus of compressive resilienceMPa Poiss0n ratio Above layer Fine grain asphalt concrete 4 1200 0.30 Middle surface layer Medium grain asphalt concrete 6 1000 0.30 Lower layer Coarse grained asphalt concrete 8 800 0.30 Base course Cement stabilized macadam 3
{"title":"Analysis of Shear Failure of Asphalt Pavement under Horizontal Force","authors":"L. Honghui, Liao Xiaojuan, Li Yuan","doi":"10.12783/dteees/peems2019/33970","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33970","url":null,"abstract":"The finite element method is used to analyze the shear stress distribution of the pavement structure under vertical load and both vertical and horizontal load. The results show that the distribution coefficient of transverse force affects the distribution of shear stress with depth; The maximum shear stress increases with the increase of the lateral force coefficient, and the two have a linear relationship. When the horizontal force is considered, the shear stress of the asphalt surface layer increases and the peak value moves upward, which may cause rutting, displacement and swelling of the asphalt pavement. It is necessary to incorporate the horizontal force into the structural design index system. Introduction With the increasing of highway traffic volume and the development of heavy transportation, especially the operation of channelized traffic in high-grade highways, the rutting of asphalt pavement has become the main disease type [1] , and the main type of rutting is the fluidity rutting caused by the shear deformation of asphalt mixture [2,3] . In the summer high temperature season, the shear strength of the asphalt mixture gradually decreases with the increase of temperature. When the shear strength decreases to less than the shear stress, the asphalt mixture will produce shear deformation. Under the repeated action of the load, the wheel track will sag and both sides will rise, forming a W-shaped rut with a cross section. At the same time, displacement and swelling and washboard is also caused by the insufficient shear strength under the action of horizontal load at high temperature. Therefore, it is of great significance to optimize the design of pavement structure and reduce the occurrence of ruts to analyze the mechanics of multibrake sections such as steep road sections and toll stations considering the horizontal force and to explore the distribution law of shear stress. The Selection of Pavement Structure Parameters and the Establishment of Finite Element Model Pavement Structure Parameters Select the commonly used semi-rigid base asphalt pavement structure in China, and the material thickness and parameters are shown in Table 1. Table 1. Calculation parameters of pavement structure. Horizon Material Thicknesscm Modulus of compressive resilienceMPa Poiss0n ratio Above layer Fine grain asphalt concrete 4 1200 0.30 Middle surface layer Medium grain asphalt concrete 6 1000 0.30 Lower layer Coarse grained asphalt concrete 8 800 0.30 Base course Cement stabilized macadam 3","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78253303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33983
Haowen Yan, Xiaolan Ye, Fang-zong Wang
Initialization is an important preliminary work in electromagnetic transient simulation which is typically executed from the periodic steady-state. To this end, researchers have proposed so far a variety of initialization methods, among which the initialization based on fixed-point iteration or the so-called the EMTP-based approach has been widely used. However, this type of method can be very time consuming for a large power system due to its weak convergence. In this paper, the initialization is described as a two-point differential boundary value problem. On this basis, the boundary value solution technique is used to solve this problem, therefore, a new electromagnetic transient initialization method is derived. The proposed method is a strict Newton algorithm, so it has better convergence than the traditional fixed-point iteration method. Case studies conducted on two typical network have confirmed the effectiveness of the proposed method. Introduction The electromagnetic transient simulation and related programs (the EMTP-type programs) are widely used in the electromagnetic transient studies of power systems. The transient behavior of a network can be represented mathematically by ordinary differential equations in the continuous time-domain. Using numerical integration methods such as the implicit trapezoidal rule to solve the ordinary differential equations, the transient solution of the network can be obtained in the discrete time-domain. The transient study of a network normally begins from the network’s steady state. If the system is lightly damped, the time for it to reach its steady state can be significant and the simulation can be prohibitively expensive. The effective initialization for electromagnetic transient simulation or the EMTP-type programs, therefore, becomes unavoidable. Alternatively, the steady state solution for the periodic ordinary differential equations may be of interest in itself for the computer-aided design of nonlinear circuits and harmonic analysis [1]. Some methods to initialize the EMTP-type programs have been proposed [2, 3]. Based on the needs of the EMTP program development, the earliest proposed electromagnetic transient initialization method should be the phasor-solution technique [4]. In this approach all the elements of a network are represented in the phasor-domain. The system solution is obtained at the fundamental system frequency by solving the network matrix equation. The so-obtained system quantities are used to generate the initial state of the network. This solution technique is simple but limited to the linear and lumped-element networks. Another important initialization method is the so-called EMTP-based approach [5]. This approach performs a network’s initialization within the EMTP solution frame. That is, the initial steady state of a network can be directly established for a given initial state by simply integrating the system equations until the response becomes periodic. From a mathem
初始化是电磁瞬变仿真中一项重要的前期工作，通常从周期稳态开始进行。为此，研究人员迄今提出了多种初始化方法，其中基于不动点迭代的初始化或所谓基于emtp的初始化方法得到了广泛的应用。但对于大型电力系统来说，这种方法的收敛性较弱，耗时较长。本文将初始化描述为两点微分边值问题。在此基础上，采用边值求解技术求解该问题，从而推导出一种新的电磁瞬变初始化方法。该方法是一种严格的牛顿算法，因此比传统的不动点迭代法具有更好的收敛性。通过对两个典型网络的实例分析，验证了该方法的有效性。电磁暂态仿真及其相关程序(emtp型程序)在电力系统的电磁暂态研究中得到了广泛的应用。网络的暂态行为可以用连续时域的常微分方程在数学上表示。利用隐式梯形法则等数值积分方法求解常微分方程，可以在离散时域内得到网络的暂态解。网络的暂态研究通常从网络的稳态开始。如果系统受到轻微的阻尼，则其达到稳定状态的时间可能会很长，并且模拟的成本可能会高得令人望而却步。因此，对电磁瞬变仿真或emtp类程序进行有效的初始化是不可避免的。或者，周期常微分方程的稳态解本身可能对非线性电路的计算机辅助设计和谐波分析很感兴趣[1]。已经提出了一些初始化emtp型程序的方法[2,3]。基于EMTP程序开发的需要，最早提出的电磁瞬态初始化方法应该是相量解法[4]。在这种方法中，网络的所有元素都在相量域中表示。通过求解网络矩阵方程，在系统基频处得到系统解。得到的系统量用于生成网络的初始状态。这种求解方法简单，但仅限于线性和集总元网络。另一个重要的初始化方法是所谓的基于emtp的方法[5]。这种方法在EMTP解决方案框架内执行网络初始化。也就是说，对于给定的初始状态，只需对系统方程进行简单积分，直至响应变为周期性，即可直接建立网络的初始稳态。从数学角度看，该方法的求解过程相当于经典的不动点迭代。众所周知，不动点迭代是一种通用的数值方法，但其收敛性不如牛顿法。因此，即使对于非线性时变网络，基于emtp的方法也能较好地预测网络的初始状态，但由于其效率较低，对于大型系统并不实用。由于相量解方法和基于emtp的技术可能不适合大型电力系统的初始化，因此人们寻求基于潮流程序的初始化技术来初始化emtp类型的程序[2]。该方法适用于大型交流电力系统，效率高，但在采用电磁暂态模型时，显然不适用于直流输电系统。注意，目前广泛使用的基于emtp的方法只是简单地一步一步地积分系统微分方程，直到瞬态响应变得可以忽略不计。这种方法的主要问题是收敛速度慢，代价高昂。为了解决这个问题，一个自然的想法是使用牛顿迭代。然而，雅可比矩阵的精确表达式通常很难得到。事实上，用有限差分法求雅可比矩阵是低效的，而且可能会导致数值误差，因为如果非线性存在，我们必须多次求解非线性微分方程。一种更准确、更有效的方法涉及求解描述非线性系统线性化的相关灵敏度系统[1,3]，但这种改进仍然不是严格的牛顿法。本文将电磁瞬变初始化描述为微分边值问题，利用边值求解技术求解初始化问题。 在这种方法中，理论上我们可以使用不同的边值方法[6]，但考虑到emtp型程序主要使用梯形规则，我们也使用梯形积分法来实现初始化。为了解决边值求解中涉及的雅可比矩阵过大的问题，本文提出了一种分块递归求解方法。理论上，所提出的初始化方法是一种严格的牛顿算法，具有较好的收敛性。第2节介绍了电磁瞬变初始化问题的数学表达式或形成。在此基础上，本节还介绍了目前广泛使用的初始化的基本不动点迭代法。第3节简单介绍了微分边值问题的求解技术，同时推导了基于该技术的初始化方法。为了进一步阐述所提出的方法，在第4节中，将所提出的方法应用于具有周期输入的一般线性微分系统，并与不动点迭代进行比较。这导致了一个有趣的结果。在第5节中，使用两个简单但典型的网络对所提出的方法进行了测试，并与不动点迭代法进行了比较。从数学的角度来看，电磁瞬变仿真就是微分初值问题的求解。即0 (，)(0)dt t dtx x f x x x，(1)其中，x和(，)t f x是n个向量。对于给定的初值0 x，我们可以通过数值积分得到状态变量t x的离散时域数值解。电磁暂态仿真主要是研究电力系统在扰动或故障条件下的暂态响应。通常，这个过程必须从一个稳态初始条件开始。这就是所谓的初始化问题。注意，在电力系统稳态时，(，)t f x在周期为t的t中是周期性的。因此，我们可以假设方程1有一个周期为t的周期解。在这种情况下，初始化的目标是确定初始状态0 x y，使Eq. 1从这个初始状态在间隔0 T上积分，我们得到周期T的周期解()T x。这本质上是一个两点边值问题的解Eq。1间隔0 T,必须满足如下边界条件:0 ()= T y x x y,(2)从0 ( ) ( , ) T T dx y f(3)我们可以表达上述问题映射为0 ( ) ( , ) T dy y y F x (4), () F y y是初始状态的函数。对于y的求解，最基本的方法是所谓的不动点迭代法，可以描述为(1)+1 0 ()(，)k T k k k dy F y y F x(5)其中，上标k表示迭代次数。此迭代必须重复，直到满足以下条件:+1 ()k k k k(y y F y(6)，其中，为所需精度。在式(5)所描述的迭代过程中，数值积分是很容易理解的，因此通常使用梯形规则，因为大多数EMTP-Type程序都使用这种积分方法。显然，我们需要在整个周期内一步一步地集成系统以完成一次迭代，并重复此过程多次，直到瞬态响应变得可以忽略不计。这正是目前emtp型程序用来获得稳态响应的方法。因此，这种方法通常也被称为基于emtp的方法。如果瞬态衰减迅速，这个方法是令人满意的。然而，对于典型的电力系统的轻阻尼网络，暂态通常衰减非常缓慢，这将使初始化非常耗时。本研究的主要目的是提高初始化的收敛性，从而提高电磁瞬变仿真的效率。为此，最重要的方法之一是用牛顿法求解方程4。即()()k k k k k k k () k k k k () k k k()(()F I J y F y y(7)其中，I为单位矩阵，F J为雅可比矩阵，()F F y J y(8)然而，从式4中可以看出，当(，)t F x为非线性时，雅可比矩阵F J的精确表达式很难得到。事实上，如果我们使用逐步积分，也就是一个级数解来计算()F中所涉及的积分项，就很难得到fj的确切表达式。由于初始化是两点边值问题，所以有效的解决方法自然是采用边值法[6]，[7]。
{"title":"Initialization of Electromagnetic Transient Simulation Using Boundary Value Solution Method","authors":"Haowen Yan, Xiaolan Ye, Fang-zong Wang","doi":"10.12783/dteees/peems2019/33983","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33983","url":null,"abstract":"Initialization is an important preliminary work in electromagnetic transient simulation which is typically executed from the periodic steady-state. To this end, researchers have proposed so far a variety of initialization methods, among which the initialization based on fixed-point iteration or the so-called the EMTP-based approach has been widely used. However, this type of method can be very time consuming for a large power system due to its weak convergence. In this paper, the initialization is described as a two-point differential boundary value problem. On this basis, the boundary value solution technique is used to solve this problem, therefore, a new electromagnetic transient initialization method is derived. The proposed method is a strict Newton algorithm, so it has better convergence than the traditional fixed-point iteration method. Case studies conducted on two typical network have confirmed the effectiveness of the proposed method. Introduction The electromagnetic transient simulation and related programs (the EMTP-type programs) are widely used in the electromagnetic transient studies of power systems. The transient behavior of a network can be represented mathematically by ordinary differential equations in the continuous time-domain. Using numerical integration methods such as the implicit trapezoidal rule to solve the ordinary differential equations, the transient solution of the network can be obtained in the discrete time-domain. The transient study of a network normally begins from the network’s steady state. If the system is lightly damped, the time for it to reach its steady state can be significant and the simulation can be prohibitively expensive. The effective initialization for electromagnetic transient simulation or the EMTP-type programs, therefore, becomes unavoidable. Alternatively, the steady state solution for the periodic ordinary differential equations may be of interest in itself for the computer-aided design of nonlinear circuits and harmonic analysis [1]. Some methods to initialize the EMTP-type programs have been proposed [2, 3]. Based on the needs of the EMTP program development, the earliest proposed electromagnetic transient initialization method should be the phasor-solution technique [4]. In this approach all the elements of a network are represented in the phasor-domain. The system solution is obtained at the fundamental system frequency by solving the network matrix equation. The so-obtained system quantities are used to generate the initial state of the network. This solution technique is simple but limited to the linear and lumped-element networks. Another important initialization method is the so-called EMTP-based approach [5]. This approach performs a network’s initialization within the EMTP solution frame. That is, the initial steady state of a network can be directly established for a given initial state by simply integrating the system equations until the response becomes periodic. From a mathem","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"40 160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83264682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33974
Jian Hao, Hao Zhang
The void in solder layer is the main factor that causes bad heat dissipation of IGBT (Insulated Gate Bipolar Transistor) module. Based on the seven-layer structure of IGBT, this article established a three-dimensional finite element model of IGBT module packaging structure and carried out its thermal analysis, then had a study on the effect of welding layer void on the temperature of IGBT chip. The overall distribution of IGBT module with or without solder hole is compared, meanwhile the article analyzed the effects of void type, size, shape, number and distribution on the temperature distribution of IGBT chips. The results show that the void in the solder layer of the chip has a great influence on the temperature of the chip. The influence of penetrating voids on chip temperature is greater than that of non-penetrating voids, the bigger the single hole is, the higher the temperature of IGBT chip. Voids of the same shape have greater influence on chip temperature at edge and corner positions than those inside the welding layer. The more concentrated the distribution of multiple holes, the higher the chip’s temperature. Therefore, in order to improve the reliability of IGBT, it is necessary to avoid voids in the chip welding layer during the packaging process.
{"title":"The Influence of Solder Void on IGBT Temperature","authors":"Jian Hao, Hao Zhang","doi":"10.12783/dteees/peems2019/33974","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33974","url":null,"abstract":"The void in solder layer is the main factor that causes bad heat dissipation of IGBT (Insulated Gate Bipolar Transistor) module. Based on the seven-layer structure of IGBT, this article established a three-dimensional finite element model of IGBT module packaging structure and carried out its thermal analysis, then had a study on the effect of welding layer void on the temperature of IGBT chip. The overall distribution of IGBT module with or without solder hole is compared, meanwhile the article analyzed the effects of void type, size, shape, number and distribution on the temperature distribution of IGBT chips. The results show that the void in the solder layer of the chip has a great influence on the temperature of the chip. The influence of penetrating voids on chip temperature is greater than that of non-penetrating voids, the bigger the single hole is, the higher the temperature of IGBT chip. Voids of the same shape have greater influence on chip temperature at edge and corner positions than those inside the welding layer. The more concentrated the distribution of multiple holes, the higher the chip’s temperature. Therefore, in order to improve the reliability of IGBT, it is necessary to avoid voids in the chip welding layer during the packaging process.","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87294126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33997
Jian Mi, Kun Wang, Qian Liu, Mingxing Zhang
In the fault detection of buried power cables, random noise in the shock discharge sound signal is difficult to remove by existing filtering methods. A fifth-order convergent independent component analysis (ICA) method based on empirical mode decomposition (EMD) is proposed to extract the impact discharge sound signal. The fifth-order convergence ICA is adopted, so that the eigenmode components decomposed by the EMD and the remaining signals are independent of each other. Using the strong correlation between the frequency spectrum of the discharge sound signal, the eigenmode component with the largest correlation between the frequency spectrum and the high signal-to-noise ratio shock discharge sound signal spectrum is automatically extracted. Finally, the shock discharge sound signal of unknown failure point is obtained. This method has the advantages of less constraints, small dependencies, and fast convergence. The simulation and experimental results further show that the discharge sound signal in the mixed signal can be effectively extracted. Introduction Buried cables are prone to failure, but the point of failure is not easily detected. If the fault cannot be dealt with in time, it will cause serious consequences. Therefore, it is of great significance to find a fast and accurate method for locating cable faults. At present, many methods are used in cable fault location, including sonic detection method, magnetic sound synchronization method, audio current induction method, etc. [1]. In these methods, the cable discharge sound signal needs to be detected and extracted. The cable discharge sound signal at the fault point of the cable is extremely susceptible to the influence of ambient noise, which makes it difficult to process the signal. The noise in the cable discharge sound signal is non-stationary random noise. Traditional filtering methods, such as the classic spectral analysis of fast Fourier transform, parametric autoregressive moving average spectral analysis [2], Kalman filter [3], etc., are difficult to remove this noise. The empirical mode decomposition method can decompose mixed signals in engineering practice [4]. However, the empirical mode decomposition method will cause aliasing of the eigenmode components of the signal, which is not conducive to the extraction of the signal. Aiming at the problems of signal decomposition by empirical mode decomposition, scholars at home and abroad have proposed many methods [5], but the processing effect is not ideal. A fifth-order convergent ICA method based on EMD is proposed to extract the impact discharge sound signal, and the effectiveness of the method is proved by simulation and field experiments. EMD-based Fifth-order Convergence ICA ICA, which is applied to the extraction of useful sound signals, has achieved good results [6]. However, ICA can be solved only when the number of observation channels is not less than the number of source signals in the mixed signal. In practical applic
在地埋电力电缆故障检测中，现有的滤波方法难以去除冲击放电声信号中的随机噪声。提出了一种基于经验模态分解(EMD)的五阶收敛独立分量分析(ICA)方法来提取冲击放电声信号。采用五阶收敛ICA，使EMD分解的特征模态分量与剩余信号相互独立。利用放电声信号频谱之间的强相关性，自动提取频谱与高信噪比冲击放电声信号频谱之间相关性最大的特征模态分量。最后得到未知失效点的冲击放电声信号。该方法具有约束少、依赖性小、收敛速度快等优点。仿真和实验结果进一步表明，该方法可以有效地提取混合信号中的放电声信号。埋地电缆容易发生故障，但故障点不易被发现。如果不能及时处理，将会造成严重的后果。因此，寻找一种快速准确的电缆故障定位方法具有重要意义。目前用于电缆故障定位的方法有很多，包括声波检测法、磁声同步法、音频电流感应法等[1]。在这些方法中，需要对电缆放电声信号进行检测和提取。电缆故障点处的电缆放电声信号极易受到环境噪声的影响，给信号处理带来困难。电缆放电声信号中的噪声是非平稳随机噪声。传统的滤波方法，如经典的快速傅立叶变换谱分析、参数自回归移动平均谱分析[2]、卡尔曼滤波[3]等，都难以去除这种噪声。经验模态分解方法在工程实践中可以对混合信号进行分解[4]。然而，经验模态分解方法会导致信号的特征模态分量混叠，不利于信号的提取。针对经验模态分解对信号分解存在的问题，国内外学者提出了许多方法[5]，但处理效果并不理想。提出了一种基于EMD的五阶收敛独立分量分析方法提取冲击放电声信号，并通过仿真和现场实验验证了该方法的有效性。基于emd的五阶收敛ICA ICA应用于有用声音信号的提取，取得了很好的效果[6]。但是，ICA只有在观测信道数不小于混合信号中源信号数的情况下才能得到解决。在实际应用中，只能获得一个观测信号。因此，ICA的使用减少了。EMD可以分解单个信号。在分解过程中，EMD不能完全保证分解分量相互独立或正交，分解得到的模态分量存在模态混叠[7]。通过对两种方法的分析，将ICA和EMD相结合。该方法不仅可以对单个信号进行分解，而且可以使分解结果相互独立。ICA中的初始分离矩阵是随机选择的，这将导致迭代次数差异较大，甚至不收敛。因此，利用松弛因子克服了对初值的依赖，增大了收敛范围。基于最大负熵的ICA算法目标函数为Eq. 1。( ) { ( )} F T k k k W E Xg W X W在公式(1),k W是分离矩阵,k是迭代的数量,E是指操作,X是观测数据,g是一个非线性函数,{()}T T E k k W Xg W X。松弛因子,具有不断地减少目标函数值的特征。由式2表示，即式3。1 1 {()} {()} T T k k k k E Xg W X W E Xg W X W (2)
{"title":"Extraction of Sound Signals from Power Cable Impulse Discharge","authors":"Jian Mi, Kun Wang, Qian Liu, Mingxing Zhang","doi":"10.12783/dteees/peems2019/33997","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33997","url":null,"abstract":"In the fault detection of buried power cables, random noise in the shock discharge sound signal is difficult to remove by existing filtering methods. A fifth-order convergent independent component analysis (ICA) method based on empirical mode decomposition (EMD) is proposed to extract the impact discharge sound signal. The fifth-order convergence ICA is adopted, so that the eigenmode components decomposed by the EMD and the remaining signals are independent of each other. Using the strong correlation between the frequency spectrum of the discharge sound signal, the eigenmode component with the largest correlation between the frequency spectrum and the high signal-to-noise ratio shock discharge sound signal spectrum is automatically extracted. Finally, the shock discharge sound signal of unknown failure point is obtained. This method has the advantages of less constraints, small dependencies, and fast convergence. The simulation and experimental results further show that the discharge sound signal in the mixed signal can be effectively extracted. Introduction Buried cables are prone to failure, but the point of failure is not easily detected. If the fault cannot be dealt with in time, it will cause serious consequences. Therefore, it is of great significance to find a fast and accurate method for locating cable faults. At present, many methods are used in cable fault location, including sonic detection method, magnetic sound synchronization method, audio current induction method, etc. [1]. In these methods, the cable discharge sound signal needs to be detected and extracted. The cable discharge sound signal at the fault point of the cable is extremely susceptible to the influence of ambient noise, which makes it difficult to process the signal. The noise in the cable discharge sound signal is non-stationary random noise. Traditional filtering methods, such as the classic spectral analysis of fast Fourier transform, parametric autoregressive moving average spectral analysis [2], Kalman filter [3], etc., are difficult to remove this noise. The empirical mode decomposition method can decompose mixed signals in engineering practice [4]. However, the empirical mode decomposition method will cause aliasing of the eigenmode components of the signal, which is not conducive to the extraction of the signal. Aiming at the problems of signal decomposition by empirical mode decomposition, scholars at home and abroad have proposed many methods [5], but the processing effect is not ideal. A fifth-order convergent ICA method based on EMD is proposed to extract the impact discharge sound signal, and the effectiveness of the method is proved by simulation and field experiments. EMD-based Fifth-order Convergence ICA ICA, which is applied to the extraction of useful sound signals, has achieved good results [6]. However, ICA can be solved only when the number of observation channels is not less than the number of source signals in the mixed signal. In practical applic","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83645885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33956
Yong-Suo Zi, Pengjun Qiu
In addition to the rigid indexes of scientific research, papers, teaching materials and monographs, the flexible indexes of teaching, ethics, professional ability and performance contribution are also added in the process of the evaluation of the titles of colleges, enterprises and institutions. Among these flexible indicators, we can only measure and quantify them according to various awards certificates, and how to reasonably quantify and grade various certificates. This brings new requirements and new problems to the evaluation of professional titles. In view of the above-mentioned new requirements and new forms of the existing series of problems, the use of blockchain distributed management technology can well solve the existing problems. Introduction In recent years, a series of new changes have taken place in the evaluation of professional titles of institutions of higher learning, enterprises and institutions. In the original evaluation framework based on papers, scientific research, teaching materials and monographs, many flexible indicators have been added. But the following problems also appear, which increase many elastic indicators, it is difficult to quantify. Basically, they can only be identified by relevant certificates or materials such as award certificates, award projects, qualification certificates, performance materials, etc. However, there are many kinds of unofficial organizations from various academic groups, social organizations and non-governmental organizations. All kinds of unofficial certificates are mixed and hard to distinguish. This brings new problems to the fairness of the evaluation work. To solve this problem is an urgent problem for us to think about and solve. This paper will take the blockchain distributed management technology as the technical core and the certificate authenticity check as the goal, and discuss the technical methods to solve the above problems one by one. Problems Existing in the Verification and Quantification of Certificate Authenticity in the Process of Professional Title Evaluation In the new evaluation method of professional titles, according to the requirements of the new evaluation documents, all kinds of certificates account for a great deal of weight in the evaluation quantification. However, the authenticity of certificate sources and the weight of certificates are two very difficult problems. How to solve these two problems, in the new title evaluation requirements, is the primary problem we cannot avoid at present. On the Verification of Certificate Authenticity in the Process of Professional Title Evaluation How to identify or check the authenticity of certificates in professional title evaluation is the first problem we must solve. If the authenticity of certificates cannot be effectively solved, there will be a serious lack of evidence in the review of evaluation data, which will bring a great test to the subsequent evaluation work and the fairness of evaluation results. The
{"title":"Research on the Inspection and Management of Certificates in the Process of Professional Title Evaluation by Blockchain Distributed Management Technology","authors":"Yong-Suo Zi, Pengjun Qiu","doi":"10.12783/dteees/peems2019/33956","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33956","url":null,"abstract":"In addition to the rigid indexes of scientific research, papers, teaching materials and monographs, the flexible indexes of teaching, ethics, professional ability and performance contribution are also added in the process of the evaluation of the titles of colleges, enterprises and institutions. Among these flexible indicators, we can only measure and quantify them according to various awards certificates, and how to reasonably quantify and grade various certificates. This brings new requirements and new problems to the evaluation of professional titles. In view of the above-mentioned new requirements and new forms of the existing series of problems, the use of blockchain distributed management technology can well solve the existing problems. Introduction In recent years, a series of new changes have taken place in the evaluation of professional titles of institutions of higher learning, enterprises and institutions. In the original evaluation framework based on papers, scientific research, teaching materials and monographs, many flexible indicators have been added. But the following problems also appear, which increase many elastic indicators, it is difficult to quantify. Basically, they can only be identified by relevant certificates or materials such as award certificates, award projects, qualification certificates, performance materials, etc. However, there are many kinds of unofficial organizations from various academic groups, social organizations and non-governmental organizations. All kinds of unofficial certificates are mixed and hard to distinguish. This brings new problems to the fairness of the evaluation work. To solve this problem is an urgent problem for us to think about and solve. This paper will take the blockchain distributed management technology as the technical core and the certificate authenticity check as the goal, and discuss the technical methods to solve the above problems one by one. Problems Existing in the Verification and Quantification of Certificate Authenticity in the Process of Professional Title Evaluation In the new evaluation method of professional titles, according to the requirements of the new evaluation documents, all kinds of certificates account for a great deal of weight in the evaluation quantification. However, the authenticity of certificate sources and the weight of certificates are two very difficult problems. How to solve these two problems, in the new title evaluation requirements, is the primary problem we cannot avoid at present. On the Verification of Certificate Authenticity in the Process of Professional Title Evaluation How to identify or check the authenticity of certificates in professional title evaluation is the first problem we must solve. If the authenticity of certificates cannot be effectively solved, there will be a serious lack of evidence in the review of evaluation data, which will bring a great test to the subsequent evaluation work and the fairness of evaluation results. The ","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91281317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33984
Chong Shen, Xiu-Lan Cheng
A type of easy-to-fabricate Schottky diode with controllable breakdown voltage is design and fabricated. The Schottky junction is formed by the contact of Aluminum electrode and light doped n-type silicon. A special comb teeth structure is designed to lower the resistance and breakdown voltage. The diodes can achieve breakdown voltage between 2V and 16V by optimizing the doping concentration of the substrate and the distance of the comb teeth. The diode has great application potential in electro-static discharge (ESD) protection circuit, due to its easy compatibility in CMOS circuit process and ability of withstanding high currents. Introduction With the development of semiconductor technology, the IC devices are scaling down, achieving higher device density and faster working frequency. However, the damage that comes with electro-static discharge (ESD) are becoming increasingly significant [1,2]. This makes developing ESD protection devices that are compatible with IC fabrication devices a necessity. Many kinds of devices can be used as ESD protection devices, including Zener diode [3,4] and transient voltage suppressor (TVS) [5,6], etc. They are both variants of PN junction diode. Schottky diode is another option for ESD protection [7,8]. Schottky diode uses certain metal materials, such as gold, silver, aluminum and platinum, as anode, and uses n-type semiconductor as cathode. The contact of these materials produces rectification property. Schottky diode has two major differences: magnitude of reverse saturation current and switching characteristic when compared with PN junction diodes, The reverse current density of a Schottky diode can be calculated from equation (1) while that of an ideal PN junction can be calculated from equation (2). JsT = A T exp (− eΦBn kT ) (1) Js = eDnnp0 Ln + eDppn0 Lp (2) In equation (1), e is the charge of an electron, A * is effective Richardson’s constant, φBn is the height of Schottky barrier, k is Boltzmann constant and T is the temperature (Kelvin). In equation (2), Dn and Dp are diffusion coefficient of minority electrons and holes, whose diffusion length is noted as Ln and Lp. np0 and pn0 are minority electron and hole density under heat balance. The transport mechanism of Schottky diode and PN junction diode is different, for the two equations above exhibit different forms. The current in PN junction is mainly determined by the diffusion of minority carrier, whereas that in Schottky junction is mainly determined by thermionic emission of majority carrier. With the same substrate doping concentration, it can be found that the reverse saturation current of Schottky diode is several magnitudes larger than that of PN junction diode. Another major difference between Schottky diode and PN junction diode is their switching speed. As a device whose current is mainly produced by majority carrier, the switching time of Schottky diode is magnitudes smaller than that of PN junction diode, whose current is mainly produ
设计并制作了一种易于制作的击穿电压可控肖特基二极管。通过铝电极与掺光n型硅的接触形成肖特基结。特殊的梳齿结构设计，降低电阻和击穿电压。通过优化衬底掺杂浓度和梳齿距离，二极管击穿电压可达到2V ~ 16V。该二极管具有易于兼容CMOS电路工艺和耐大电流的特点，在静电放电保护电路中具有很大的应用潜力。随着半导体技术的发展，集成电路器件的小型化，器件密度越来越高，工作频率越来越快。然而，静电放电(ESD)带来的损害越来越严重[1,2]。这使得开发与IC制造设备兼容的ESD保护器件成为必要。多种器件可作为ESD保护器件，包括齐纳二极管[3,4]和瞬态电压抑制器(TVS)[5,6]等。它们都是PN结二极管的变体。肖特基二极管是ESD保护的另一个选择[7,8]。肖特基二极管以金、银、铝、铂等一定的金属材料为阳极，以n型半导体为阴极。这些材料的接触产生整流性能。肖特基二极管有两个主要区别:级反向饱和电流和开关特性与PN结二极管相比,肖特基二极管的反向电流密度可以计算从方程(1)的一个理想的PN结可以计算从方程(2),JsT = T exp(−eΦBn kT) (1) Js = eDnnp0 Ln + eDppn0 Lp在方程(1)(2),e是电子的电荷,*是有效的理查森的常数,φBn肖特基势垒的高度,k是玻尔兹曼常数，T是温度(开尔文)式(2)中，Dn和Dp为少数电子和空穴的扩散系数，其扩散长度记为Ln和Lp。Np0和pn0为热平衡下的少数电子和空穴密度。肖特基二极管和PN结二极管的输运机制是不同的，因为上述两种方程的形式不同。PN结的电流主要由少数载流子的扩散决定，而肖特基结的电流主要由多数载流子的热离子发射决定。在衬底掺杂浓度相同的情况下，肖特基二极管的反向饱和电流比PN结二极管的反向饱和电流大几个数量级。肖特基二极管和PN结二极管的另一个主要区别是它们的开关速度。肖特基二极管作为主要由多数载流子产生电流的器件，其开关时间比主要由少数载流子产生电流的PN结二极管的开关时间要小几个数量级[9]。肖特基二极管的典型制造工艺采用垂直结构[10,11]，两个电极位于芯片的不同侧面。还采用了外延工艺，如图1所示。垂直结构在电路中占用较大空间，不能集成到CMOS芯片中。在这种结构中，精确的击穿电压控制也比较困难。图1所示。肖特基二极管的典型结构。为此，本文提出了一种特殊的平面梳状肖特基二极管结构，使其易于在单芯片上集成。而且，通过调整梳齿的距离，可以很容易地控制装置的击穿电压。同时，由于没有外延工艺，可以降低制造成本。为了减小二极管的串联电阻，提高二极管的性能，采用了梳状结构[12]。接触区域的长度记为L，宽度记为w，两个接触区域的距离记为d。结构俯视图如图2所示。图2。肖特基二极管的俯视图。肖特基二极管的垂直轮廓如图3所示。该器件由n衬底、重掺杂区、SiO2层和金属电极组成。图3。肖特基二极管的垂直轮廓。图4。制作工艺流程图。图5。制作的器件照片。选择了两种不同类型的4英寸n型晶圆进行制造。一个掺杂浓度为5×10 13 cm -3，厚度为525um，另一个掺杂浓度为1×10 16 cm -3，厚度为525um。第一步是用丙酮和异丙醇清洗晶圆表面，然后用等离子体增强化学气相沉积(PECVD)沉积250nm厚的SiO2层。SiO2层被蚀刻以形成肖特基二极管的区域和反应离子蚀刻(RIE)后续对准的标记。
{"title":"Design and Fabrication of Planar Schottky Diode for Electrostatic Discharge Protection","authors":"Chong Shen, Xiu-Lan Cheng","doi":"10.12783/dteees/peems2019/33984","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33984","url":null,"abstract":"A type of easy-to-fabricate Schottky diode with controllable breakdown voltage is design and fabricated. The Schottky junction is formed by the contact of Aluminum electrode and light doped n-type silicon. A special comb teeth structure is designed to lower the resistance and breakdown voltage. The diodes can achieve breakdown voltage between 2V and 16V by optimizing the doping concentration of the substrate and the distance of the comb teeth. The diode has great application potential in electro-static discharge (ESD) protection circuit, due to its easy compatibility in CMOS circuit process and ability of withstanding high currents. Introduction With the development of semiconductor technology, the IC devices are scaling down, achieving higher device density and faster working frequency. However, the damage that comes with electro-static discharge (ESD) are becoming increasingly significant [1,2]. This makes developing ESD protection devices that are compatible with IC fabrication devices a necessity. Many kinds of devices can be used as ESD protection devices, including Zener diode [3,4] and transient voltage suppressor (TVS) [5,6], etc. They are both variants of PN junction diode. Schottky diode is another option for ESD protection [7,8]. Schottky diode uses certain metal materials, such as gold, silver, aluminum and platinum, as anode, and uses n-type semiconductor as cathode. The contact of these materials produces rectification property. Schottky diode has two major differences: magnitude of reverse saturation current and switching characteristic when compared with PN junction diodes, The reverse current density of a Schottky diode can be calculated from equation (1) while that of an ideal PN junction can be calculated from equation (2). JsT = A T exp (− eΦBn kT ) (1) Js = eDnnp0 Ln + eDppn0 Lp (2) In equation (1), e is the charge of an electron, A * is effective Richardson’s constant, φBn is the height of Schottky barrier, k is Boltzmann constant and T is the temperature (Kelvin). In equation (2), Dn and Dp are diffusion coefficient of minority electrons and holes, whose diffusion length is noted as Ln and Lp. np0 and pn0 are minority electron and hole density under heat balance. The transport mechanism of Schottky diode and PN junction diode is different, for the two equations above exhibit different forms. The current in PN junction is mainly determined by the diffusion of minority carrier, whereas that in Schottky junction is mainly determined by thermionic emission of majority carrier. With the same substrate doping concentration, it can be found that the reverse saturation current of Schottky diode is several magnitudes larger than that of PN junction diode. Another major difference between Schottky diode and PN junction diode is their switching speed. As a device whose current is mainly produced by majority carrier, the switching time of Schottky diode is magnitudes smaller than that of PN junction diode, whose current is mainly produ","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81906614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/34019
Jianli Zhao, Zheng Kou, Linxi Huang
The simulated calculation model of transformer winding leakage magnetic field is developed based on the development of C# language, and combined with electromagnetic field and transformer theory of this paper. Taking a transformer winding data as an example, the axisymmetric two-dimensional model is established to verify the engineering application effectiveness of the software. Introduction As the continuous expand of the scale of the power grid, the stability requirements for transformer performance are much higher. At the same time, as the capacity of the transformer continues to increase, the loss and thermal and dynamic stability of the transformer are attracted increasingly attention from manufacturers and power grid [1, 2], The premise that the above problems can be analyzed accurately is to accurately analyze the leakage magnetic field of the transformer winding. With the development of numerical calculation, finite element software has sufficient engineering precision to meet the requirements of electromagnetic field calculation [3], but in the general numerical calculation, the calculating model established can only be used to analyze specific physical problems, and its calculating model cannot be applied to analyze other issues [4]. Therefore, in-depth study of the types of transformer windings, how to automatically establish a method to accurately describe various winding models through simple input has become an urgent research topic. Mao Fengchun et al. recommended the model modeled by pie (line) by comparing the geometric models of windings with different fineness levels [5]. However, for large-scale power transformer, the windings contain various structural forms and structures is complex, which require high technical capabilities and experience of analysts. And the manual modeling method is much time consuming. Therefore, the large-scale power transformer winding modeling software which could apply to design, analyze and verify actual transformers is necessary to be developed. The winding is the core component of the transformer, and its variety is various. It is a top priority to construct the model to reasonably establish the winding conductor model to realize the analysis of the distribution of the winding leakage magnetic field. Based on the theory of transformer leakage magnetic field analysis, the calculation and modeling methods of magnetic flux leakage in transformer windings is discussed in this paper. The object-oriented analysis and design software is adopted, the class required for winding modeling is reasonably abstracted. According to various windings, the winding model in which the conductor ring is as the base and the layer unit is as the core are proposed. The C# language is used as a tool to develop simulation modeling software for transformer winding leakage magnetic field. The coil model for different structural forms of the transformer is established quickly and easily via the analysis software, and the outpu
为了减少有限元单元的数量，不使用核心柱和轭架作为解域。
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Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33992
Mengjie Luo, Xiao-ming Yao, Chaoyu Li
There are two kinds of abnormal conditions in the RFID-enabled supply chain such as forgery and miss operation, but the existing anti-counterfeiting model is not used to distinguish them. In this regard, based on the definition of abnormal activity and its dependencies, this paper proposes the abnormality detection rules of the “frequent pattern” yielded by big data techniques. From a multi-dimensional perspective, combined with EPC data and prior information sent from the previous nodes, it can effectively distinguish between forgery activities and operational anomalies. Consequently, asecure visualization system for anti-counterfeiting and anomaly monitoring in rfid-enabled supply chain is implemented with satisfactory results
{"title":"Multi-dimensional Anti-counterfeiting Anomaly Monitoring Model Based on RFID in Supply Chain","authors":"Mengjie Luo, Xiao-ming Yao, Chaoyu Li","doi":"10.12783/dteees/peems2019/33992","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33992","url":null,"abstract":"There are two kinds of abnormal conditions in the RFID-enabled supply chain such as forgery and miss operation, but the existing anti-counterfeiting model is not used to distinguish them. In this regard, based on the definition of abnormal activity and its dependencies, this paper proposes the abnormality detection rules of the “frequent pattern” yielded by big data techniques. From a multi-dimensional perspective, combined with EPC data and prior information sent from the previous nodes, it can effectively distinguish between forgery activities and operational anomalies. Consequently, asecure visualization system for anti-counterfeiting and anomaly monitoring in rfid-enabled supply chain is implemented with satisfactory results","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83958492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.12783/dteees/peems2019/33938
Zhibiao Mai, Z. Zhong, W. Luo, Xiao-peng Peng
In order to make the traditional handmade paper in Guangdong more suitable for modern application, this article tryed to improve the manufacturing technology by some practical experiments. In these experiments, the mechanical properties and surface effects of the paper was improved by compositing material, sizing surface, adding texture, embossing and polishing. These experiments show that the handmade paper has good processing adaptability, it can apply many manufacturing processes flexibly, and can get a lot of effect with beautiful form and good performance. All of these technologies can provide a good material basis for modern application and cultural inheritance, which can be used in many paper mills and folk cultural institutions widely. Introduction Paper is a flat and even sheet made by depositing plant fiber, mineral fiber, animal fiber, chemical fiber or mixtures of these fibers. They are made by drying with suitable forming equipment [1]. It can be seen from the above that as long as the handmade paper does not break away from the process of fiber flaking, it still belongs to the category of papermaking. Therefore, we can make many kinds of paper for different aesthetic characteristics and meet the needs of modern creative design by adding materials and changing part of the process. Of course, we should implement it on the premise of preserving the historical flavor and technological essence of handmade paper. This can give more new functions and roles to Chinese traditional handmade paper, which is of great significance. There are two aspects to change the process of traditional handmade paper: one is to improve the existing process; the other is to add the follow-up process. The advanced technology of modern mechanical paper is interspersed in the process of manual paper making to improve the quality of handmade paper, so as to realize the activation and protection goals of traditional handmade paper from remote mountains to cities and from ancient times to modern times. Adding Composite Materials in Papermaking Using natural materials is the characteristic advantage of traditional handmade paper, it also brings the disadvantage of blank appearance. If put other pulp into the raw materials, such as wood pulp, cotton pulp, straw pulp and fluorescent powder, to reconcile the appearance of traditional manual paper. It will get a special effect [2]. In the first experiment, we add straw pulp and Broussonetia bark pulp into bamboo pulp. The mixing of these pulp will deepen the paper color, let the color become dark. The effect of straw pulp on the paper texture is not obvious, but if the rough bark is added, in addition to the deepening of the color of the paper, the lines of the bark will also make the paper present an abstract texture, making the appearance of the paper more special. After many tests, when the ratio of each size is as shown in Table 1, the paper can achieve a good balance between appearance and texture. Another way to m
{"title":"Research on the Technical Improvement of Traditional Handmade Paper in Guangdong, China","authors":"Zhibiao Mai, Z. Zhong, W. Luo, Xiao-peng Peng","doi":"10.12783/dteees/peems2019/33938","DOIUrl":"https://doi.org/10.12783/dteees/peems2019/33938","url":null,"abstract":"In order to make the traditional handmade paper in Guangdong more suitable for modern application, this article tryed to improve the manufacturing technology by some practical experiments. In these experiments, the mechanical properties and surface effects of the paper was improved by compositing material, sizing surface, adding texture, embossing and polishing. These experiments show that the handmade paper has good processing adaptability, it can apply many manufacturing processes flexibly, and can get a lot of effect with beautiful form and good performance. All of these technologies can provide a good material basis for modern application and cultural inheritance, which can be used in many paper mills and folk cultural institutions widely. Introduction Paper is a flat and even sheet made by depositing plant fiber, mineral fiber, animal fiber, chemical fiber or mixtures of these fibers. They are made by drying with suitable forming equipment [1]. It can be seen from the above that as long as the handmade paper does not break away from the process of fiber flaking, it still belongs to the category of papermaking. Therefore, we can make many kinds of paper for different aesthetic characteristics and meet the needs of modern creative design by adding materials and changing part of the process. Of course, we should implement it on the premise of preserving the historical flavor and technological essence of handmade paper. This can give more new functions and roles to Chinese traditional handmade paper, which is of great significance. There are two aspects to change the process of traditional handmade paper: one is to improve the existing process; the other is to add the follow-up process. The advanced technology of modern mechanical paper is interspersed in the process of manual paper making to improve the quality of handmade paper, so as to realize the activation and protection goals of traditional handmade paper from remote mountains to cities and from ancient times to modern times. Adding Composite Materials in Papermaking Using natural materials is the characteristic advantage of traditional handmade paper, it also brings the disadvantage of blank appearance. If put other pulp into the raw materials, such as wood pulp, cotton pulp, straw pulp and fluorescent powder, to reconcile the appearance of traditional manual paper. It will get a special effect [2]. In the first experiment, we add straw pulp and Broussonetia bark pulp into bamboo pulp. The mixing of these pulp will deepen the paper color, let the color become dark. The effect of straw pulp on the paper texture is not obvious, but if the rough bark is added, in addition to the deepening of the color of the paper, the lines of the bark will also make the paper present an abstract texture, making the appearance of the paper more special. After many tests, when the ratio of each size is as shown in Table 1, the paper can achieve a good balance between appearance and texture. Another way to m","PeriodicalId":11369,"journal":{"name":"DEStech Transactions on Environment, Energy and Earth Science","volume":"25 6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80824121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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