Pub Date : 2024-09-12DOI: 10.1088/1402-4896/ad75c6
Longfeng Zhao, Wei Hong, Tingyu Liu, Hao Hu and Jiachen Zhu
Compensation mechanism following Ca substitution in K sites was computed using GULP. Utilizing density functional theory for three charge states, the impact of defect clusters CaK + VK/CaK + VH on potassium dihydrogen phosphate (KDP) crystals in both phases was assessed. Corrections to the band edge and defect formation energies were made employing hybridization floods HSE06 and FNV. Neutral and −1 valence defect states emerged. Cluster defects induced pronounced lattice distortion in PE-KDP. Notably, PE-KDP exhibited an additional photoemission of 2.89 eV, signifying a substantial structural impact. Comparative stability analysis favored FE-KDP, offering theoretical guidance for KDP crystal utilization.
使用 GULP 计算了 K 位点中 Ca 取代后的补偿机制。利用三种电荷态的密度泛函理论，评估了缺陷簇 CaK + VK/CaK + VH 对磷酸二氢钾 (KDP) 两相晶体的影响。利用杂化洪水 HSE06 和 FNV 对带边和缺陷形成能量进行了修正。出现了中性和-1价缺陷状态。簇状缺陷在 PE-KDP 中引起了明显的晶格畸变。值得注意的是，PE-KDP 出现了 2.89 eV 的额外光辐射，这表明它对结构产生了重大影响。稳定性比较分析倾向于 FE-KDP，为 KDP 晶体的利用提供了理论指导。
{"title":"Influence of Ca-substituted K-induced cluster defects on the electronic structure and optical properties of KDP crystals","authors":"Longfeng Zhao, Wei Hong, Tingyu Liu, Hao Hu and Jiachen Zhu","doi":"10.1088/1402-4896/ad75c6","DOIUrl":"https://doi.org/10.1088/1402-4896/ad75c6","url":null,"abstract":"Compensation mechanism following Ca substitution in K sites was computed using GULP. Utilizing density functional theory for three charge states, the impact of defect clusters CaK + VK/CaK + VH on potassium dihydrogen phosphate (KDP) crystals in both phases was assessed. Corrections to the band edge and defect formation energies were made employing hybridization floods HSE06 and FNV. Neutral and −1 valence defect states emerged. Cluster defects induced pronounced lattice distortion in PE-KDP. Notably, PE-KDP exhibited an additional photoemission of 2.89 eV, signifying a substantial structural impact. Comparative stability analysis favored FE-KDP, offering theoretical guidance for KDP crystal utilization.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"69 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad7708
Aneta Salova, Asad Syed, Rafid Kamal Jameel, Morug Salih Mahdi, Aseel Salah Mansoor, Usama Kadem Radi, Ameer Hassan Idan, Hind A AL-Shwaiman, Manjula Subramaniam, Ling Shing Wong and Baadal Jushi Janani
The primary objective of this study was to create and analyze a new type of LaFeO3/methylcellulose/multi-walled carbon nanotubes-NiCu2O4/Zn nanocomposite, called LFO/MC/MWCNT-NCO/Z, which has multiple functions. Structural investigation using field emission scanning electron microscopy showed that the nanoparticles (40–50 nm) were evenly distributed throughout the nanocomposite, suggesting that they were successfully incorporated without any clumping. FTIR research verified the existence of functional groups that facilitate electrostatic interactions with contaminants, hence strengthening catalytic performance and improving adsorption efficiency. The BET analysis revealed a significantly high specific surface area of 72.61 m2/g, which greatly enhances its ability to adsorb substances. The nanocomposite demonstrated high removal efficiency in adsorption (74.55%), photocatalysis (68.19%), and sonocatalysis (91.22%) procedures, highlighting its potential for effectively removing bisphenol A as organic pollutants. The synthesized LFO/MC/MWCNT-NCO/Z nanocomposite shows great potential in effectively eliminating organic contaminants from water solutions. This offers a sustainable way to address water pollution and protect human health and the environment.
{"title":"Adsorption, photocatalysis, and sonocatalytic activities of LaFeO3/methylcellulose/multi-walled carbon nanotubes-NiCu2O4/Zn for removal of organic pollutant: preparation, main factor, and mechanism","authors":"Aneta Salova, Asad Syed, Rafid Kamal Jameel, Morug Salih Mahdi, Aseel Salah Mansoor, Usama Kadem Radi, Ameer Hassan Idan, Hind A AL-Shwaiman, Manjula Subramaniam, Ling Shing Wong and Baadal Jushi Janani","doi":"10.1088/1402-4896/ad7708","DOIUrl":"https://doi.org/10.1088/1402-4896/ad7708","url":null,"abstract":"The primary objective of this study was to create and analyze a new type of LaFeO3/methylcellulose/multi-walled carbon nanotubes-NiCu2O4/Zn nanocomposite, called LFO/MC/MWCNT-NCO/Z, which has multiple functions. Structural investigation using field emission scanning electron microscopy showed that the nanoparticles (40–50 nm) were evenly distributed throughout the nanocomposite, suggesting that they were successfully incorporated without any clumping. FTIR research verified the existence of functional groups that facilitate electrostatic interactions with contaminants, hence strengthening catalytic performance and improving adsorption efficiency. The BET analysis revealed a significantly high specific surface area of 72.61 m2/g, which greatly enhances its ability to adsorb substances. The nanocomposite demonstrated high removal efficiency in adsorption (74.55%), photocatalysis (68.19%), and sonocatalysis (91.22%) procedures, highlighting its potential for effectively removing bisphenol A as organic pollutants. The synthesized LFO/MC/MWCNT-NCO/Z nanocomposite shows great potential in effectively eliminating organic contaminants from water solutions. This offers a sustainable way to address water pollution and protect human health and the environment.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"5 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad76e3
Pengfei Ding, Juan Zhang and Jingge Zhu
In this paper, a new method for generating multi-scroll chaotic attractors by introducing a new memristor model into an improved Chua’s system is presented. The dynamic characteristics of the system are analyzed, including equilibria and stability, bifurcation diagrams, Lyapunov exponents and phase diagrams. Strikingly, it can exhibit three-scroll, four-scroll and five-scroll hidden attractors by only changing one system parameter and different shapes of chaotic attractors coexist with the same parameter. Furthermore, the high randomness of the system is verified through 0–1 test and NIST test. By using the high randomness of the system, an image encryption algorithm (IEA) is designed to guarantee the secure and efficient transmission of digital images. This IEA uses whirlpool transformation to scramble pixel positions and DNA computation to diffuse pixel values. The simulation and performance analysis results indicate that the proposed IEA has high security and reliable encryption performance, which in turn confirms the availability of the new memristor-based Chua’s chaotic system.
本文提出了一种新方法，通过在改进的蔡氏系统中引入新的忆阻器模型来生成多卷混沌吸引子。本文分析了该系统的动态特性，包括平衡和稳定性、分岔图、Lyapunov 指数和相图。引人注目的是，只需改变一个系统参数，它就能表现出三卷、四卷和五卷隐藏吸引子，而且同一参数下不同形状的混沌吸引子并存。此外，系统的高随机性还通过 0-1 测试和 NIST 测试得到了验证。利用系统的高随机性，设计了一种图像加密算法（IEA），以保证数字图像的安全高效传输。这种 IEA 利用漩涡变换来扰乱像素位置，并利用 DNA 计算来扩散像素值。仿真和性能分析结果表明，所提出的IEA具有较高的安全性和可靠的加密性能，这反过来又证实了基于忆阻器的新型蔡氏混沌系统的可用性。
{"title":"Improved Chua’s chaotic system with a novel memristor: generating multi-scroll hidden attractors and applications in image encryption","authors":"Pengfei Ding, Juan Zhang and Jingge Zhu","doi":"10.1088/1402-4896/ad76e3","DOIUrl":"https://doi.org/10.1088/1402-4896/ad76e3","url":null,"abstract":"In this paper, a new method for generating multi-scroll chaotic attractors by introducing a new memristor model into an improved Chua’s system is presented. The dynamic characteristics of the system are analyzed, including equilibria and stability, bifurcation diagrams, Lyapunov exponents and phase diagrams. Strikingly, it can exhibit three-scroll, four-scroll and five-scroll hidden attractors by only changing one system parameter and different shapes of chaotic attractors coexist with the same parameter. Furthermore, the high randomness of the system is verified through 0–1 test and NIST test. By using the high randomness of the system, an image encryption algorithm (IEA) is designed to guarantee the secure and efficient transmission of digital images. This IEA uses whirlpool transformation to scramble pixel positions and DNA computation to diffuse pixel values. The simulation and performance analysis results indicate that the proposed IEA has high security and reliable encryption performance, which in turn confirms the availability of the new memristor-based Chua’s chaotic system.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"15 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad76e2
Hu He
Carbon-doped silicon dioxide (SiCOH) film is currently regarded as one of the most promising low-k materials in the integrated circuits (ICs) industry for advanced technology nodes. However, there have been limited studies on the thermal properties of SiCOH compared to its electrical and mechanical properties. In this study, we investigate the thermal conductivity of SiCOH thin films through molecular dynamics simulations (MD) and experimental characterizations. Our findings indicate that the size effect on thermal conductivity at 300 K is negligible when the thickness of SiCOH film is less than 20 nm. Additionally, we observe a contrasting temperature dependence law for the thermal conductivity of SiCOH thin films compared to crystal SiO2 thin films. Furthermore, we demonstrate a significant decrease in thermal conductivity with increasing porosity in SiCOH films; specifically, an increase in porosity from 5.35% to 42.77% results in a 60% reduction in thermal conductivity. Moreover, we validate our simulation results by characterizing the thermal conductivity of SiCOH using 3 method.
{"title":"Heat transport in SiCOH thin films: an experimental and molecular dynamics study","authors":"Hu He","doi":"10.1088/1402-4896/ad76e2","DOIUrl":"https://doi.org/10.1088/1402-4896/ad76e2","url":null,"abstract":"Carbon-doped silicon dioxide (SiCOH) film is currently regarded as one of the most promising low-k materials in the integrated circuits (ICs) industry for advanced technology nodes. However, there have been limited studies on the thermal properties of SiCOH compared to its electrical and mechanical properties. In this study, we investigate the thermal conductivity of SiCOH thin films through molecular dynamics simulations (MD) and experimental characterizations. Our findings indicate that the size effect on thermal conductivity at 300 K is negligible when the thickness of SiCOH film is less than 20 nm. Additionally, we observe a contrasting temperature dependence law for the thermal conductivity of SiCOH thin films compared to crystal SiO2 thin films. Furthermore, we demonstrate a significant decrease in thermal conductivity with increasing porosity in SiCOH films; specifically, an increase in porosity from 5.35% to 42.77% results in a 60% reduction in thermal conductivity. Moreover, we validate our simulation results by characterizing the thermal conductivity of SiCOH using 3 method.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"29 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad7709
J Praveen and S K Narasimhamurthy
In this research, we focus on modelling a wormhole using Finsler-Randers geometry. By applying the Barthel connection from the range of Finslerian connections, we have developed a new wormhole metric, termed the osculating Barthel-Finsler-Randers metric, through the osculating-Riemannian method within the Finsler-Randers framework. The fundamental field equations are formulated in terms of the obtained metric tensor characterised by η(r), which plays a pivotal role in characterizing the anisotropy of the model. To explore the application of Finsler geometry in addressing the existence of a wormhole, we adopt an exponential shape function. Further, in order to streamline the computational aspects of our analysis, and to discuss the effect of anisotropy effect of Finsler Rander geometry, we adopt a specific functional form for the anisotropic parameter where α is a constant with implications for the anisotropy, among various possibilities for η(r) a non-zero analytical component of vector field in Randers metric. In addition, we consider three distinct values for the exponent n = −1, 0, and 1 and subsequently, we proceed to develop two distinct models for each of these three values of n with constant and non-constant redshift function. We analyse the physical implications of η(r) on the energy conditions. Our results demonstrate the crucial impact of anisotropy on the stability and structure of wormholes, emphasizing the requirement of exotic matter under specific conditions. This research deepens the understanding of wormhole physics within Finsler geometry, shedding light on the theoretical frameworks essential for the existence and stability of these cosmic structures.
在这项研究中，我们的重点是利用芬斯勒-兰德斯几何建立虫洞模型。通过应用芬斯勒连接范围中的巴特尔连接，我们在芬斯勒-兰德斯框架内，用循环黎曼法建立了一种新的虫洞度量，称为循环巴特尔-芬斯勒-兰德斯度量。基本场方程是根据得到的以η(r)为特征的度量张量来表述的，η(r)在表征模型的各向异性方面起着关键作用。为了探索芬斯勒几何在解决虫洞存在问题上的应用，我们采用了指数形状函数。此外，为了简化分析的计算，并讨论芬斯勒-兰德几何的各向异性效应，我们采用了一种特定的各向异性参数函数形式，其中α是一个常数，对各向异性有影响，η(r)是兰德斯公设中矢量场的一个非零分析分量。此外，我们还考虑了指数 n =-1、0 和 1 的三个不同值，随后，我们为这三个 n 值分别建立了恒定和非恒定红移函数的两个不同模型。我们分析了η(r)对能量条件的物理影响。我们的结果证明了各向异性对虫洞稳定性和结构的关键影响，强调了在特定条件下对奇异物质的要求。这项研究加深了对芬斯勒几何中虫洞物理学的理解，揭示了这些宇宙结构的存在和稳定性所必需的理论框架。
{"title":"Developing novel wormhole metrics in finsler-randers geometry using the barthel connection and osculating-riemannian method","authors":"J Praveen and S K Narasimhamurthy","doi":"10.1088/1402-4896/ad7709","DOIUrl":"https://doi.org/10.1088/1402-4896/ad7709","url":null,"abstract":"In this research, we focus on modelling a wormhole using Finsler-Randers geometry. By applying the Barthel connection from the range of Finslerian connections, we have developed a new wormhole metric, termed the osculating Barthel-Finsler-Randers metric, through the osculating-Riemannian method within the Finsler-Randers framework. The fundamental field equations are formulated in terms of the obtained metric tensor characterised by η(r), which plays a pivotal role in characterizing the anisotropy of the model. To explore the application of Finsler geometry in addressing the existence of a wormhole, we adopt an exponential shape function. Further, in order to streamline the computational aspects of our analysis, and to discuss the effect of anisotropy effect of Finsler Rander geometry, we adopt a specific functional form for the anisotropic parameter where α is a constant with implications for the anisotropy, among various possibilities for η(r) a non-zero analytical component of vector field in Randers metric. In addition, we consider three distinct values for the exponent n = −1, 0, and 1 and subsequently, we proceed to develop two distinct models for each of these three values of n with constant and non-constant redshift function. We analyse the physical implications of η(r) on the energy conditions. Our results demonstrate the crucial impact of anisotropy on the stability and structure of wormholes, emphasizing the requirement of exotic matter under specific conditions. This research deepens the understanding of wormhole physics within Finsler geometry, shedding light on the theoretical frameworks essential for the existence and stability of these cosmic structures.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"29 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad764a
Kourosh Shirvani, Morteza Taheri and Tahere Ebrahimi
The main solution to the challenge of maintaining maximum sealing in the compressor section of each gas turbine is the use of abradable coatings. These coatings have a double duty, including (a) maintaining the lagging and (b) protecting the tips of the rotor blades. Choosing the type of abradable coating primarily depends on the service temperature of the coating. Nickel-graphite (Ni-G) coating is a good choice for use up to 480 °C and, or steel/sub-alloy rotor blades. In this research, the Ni-G coating was applied by the flame spraying method of Ni-G powder with a thickness of about 250 μm on an SS420 stainless steel substrate. The effect of the composition of the bonding layer was also investigated using two compositions, Ni-5Al and NiCrAlY. Obtaining the knowledge of applying Ni-G coating by flame spraying, identifying the structural and compositional characteristics of the coating (through optical and electron metallography), and the effect that oxidation can have on the tribological behavior of the coating were among the goals of this project. The best conditions for spraying the Ni-G coating were achieved an oxygen gas pressure of 6 bar, oxygen flow rate of 18 L min−1, acetylene pressure of 1.5 bar, acetylene flow rate of 24 L min−1, and the distance between the gun head and the sample surface was 22 cm. The results showed that placing the coating in oxidizing conditions increases its coefficient of friction. The increase in the coefficient of friction was attributed to the formation of oxide shells on the surface of the coating after 500 h of exposure to oxidation conditions. Corresponding to the higher coefficient of friction, the oxidized coating showed a decrease in wear resistance as a result of oxidation. This result can show the decrease in abradable of this coating with increasing service time.
{"title":"The effect of oxidation on tribology behavior of nickel-graphite coated stainless steel SS420","authors":"Kourosh Shirvani, Morteza Taheri and Tahere Ebrahimi","doi":"10.1088/1402-4896/ad764a","DOIUrl":"https://doi.org/10.1088/1402-4896/ad764a","url":null,"abstract":"The main solution to the challenge of maintaining maximum sealing in the compressor section of each gas turbine is the use of abradable coatings. These coatings have a double duty, including (a) maintaining the lagging and (b) protecting the tips of the rotor blades. Choosing the type of abradable coating primarily depends on the service temperature of the coating. Nickel-graphite (Ni-G) coating is a good choice for use up to 480 °C and, or steel/sub-alloy rotor blades. In this research, the Ni-G coating was applied by the flame spraying method of Ni-G powder with a thickness of about 250 μm on an SS420 stainless steel substrate. The effect of the composition of the bonding layer was also investigated using two compositions, Ni-5Al and NiCrAlY. Obtaining the knowledge of applying Ni-G coating by flame spraying, identifying the structural and compositional characteristics of the coating (through optical and electron metallography), and the effect that oxidation can have on the tribological behavior of the coating were among the goals of this project. The best conditions for spraying the Ni-G coating were achieved an oxygen gas pressure of 6 bar, oxygen flow rate of 18 L min−1, acetylene pressure of 1.5 bar, acetylene flow rate of 24 L min−1, and the distance between the gun head and the sample surface was 22 cm. The results showed that placing the coating in oxidizing conditions increases its coefficient of friction. The increase in the coefficient of friction was attributed to the formation of oxide shells on the surface of the coating after 500 h of exposure to oxidation conditions. Corresponding to the higher coefficient of friction, the oxidized coating showed a decrease in wear resistance as a result of oxidation. This result can show the decrease in abradable of this coating with increasing service time.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"36 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Copper-zinc-tin-sulfur (CZTS) thin films, prepared through a dip-coating solution method, present a highly attractive option as absorber materials for thin-film solar cells. This is due to their affordability, environmentally friendly composition, and abundant availability of raw materials. Although films processed with hydrazine-based solutions have achieved the highest efficiency of approximately 12.6%, the toxic and carcinogenic nature of hydrazine negates these advantages. In the ongoing global research on solution-based processing methods, the size of the grains has emerged as a critical factor in the fabrication of efficient solar cells. In our study, we have successfully prepared CZTS thin films with a pure kesterite phase, characterized by large micro-sized grains, using a dip-coating process with an ethanol-based precursor solution, followed by sulfurization. We investigated how the grain size evolves with varying sulfurization temperatures. Notably, we observed that increasing the temperature led to larger and more uniform grain growth. These results underscore the potential of our approach for the straightforward production of high-quality films with sizable grains, ultimately enhancing their photosensitivity and making them a promising candidate for efficient solar cell applications.
{"title":"Influence of sulfurization temperature on grain growth in Cu2ZnSnS4 thin films synthesized for solar cell applications","authors":"Indu Gupta, Shivani Singla, Prakash Kanjariya, Rahul Jain, Bhaskar Chandra Mohanty and Manas Nayak","doi":"10.1088/1402-4896/ad764c","DOIUrl":"https://doi.org/10.1088/1402-4896/ad764c","url":null,"abstract":"Copper-zinc-tin-sulfur (CZTS) thin films, prepared through a dip-coating solution method, present a highly attractive option as absorber materials for thin-film solar cells. This is due to their affordability, environmentally friendly composition, and abundant availability of raw materials. Although films processed with hydrazine-based solutions have achieved the highest efficiency of approximately 12.6%, the toxic and carcinogenic nature of hydrazine negates these advantages. In the ongoing global research on solution-based processing methods, the size of the grains has emerged as a critical factor in the fabrication of efficient solar cells. In our study, we have successfully prepared CZTS thin films with a pure kesterite phase, characterized by large micro-sized grains, using a dip-coating process with an ethanol-based precursor solution, followed by sulfurization. We investigated how the grain size evolves with varying sulfurization temperatures. Notably, we observed that increasing the temperature led to larger and more uniform grain growth. These results underscore the potential of our approach for the straightforward production of high-quality films with sizable grains, ultimately enhancing their photosensitivity and making them a promising candidate for efficient solar cell applications.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"26 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad76e5
Yanzhang Wang
With fast-developing Internet and communication, the security transmission of image in network has become a research highlight. So far, researchers have designed a lot of image encryption methods based on chaotic models, some of them are not secure enough. To enhance security of image transmission on the network, in this paper, an image encryption method is developed from a 3D memeristive FitzHugh-Nagumo (FHN) neuron. First, a 3D memeristive FHN model is obtained by connecting a memeristor into a 2D FHN model, and dynamics for 3D FHN model are estimated by applying phase diagrams, bifurcation and Lyapunov exponent. Then, an image encryption algorithm is proposed by using this 3D model. Finally, security of encryption algorithm is estimated. Simulation results confirm the effectiveness of encryption scheme.
{"title":"An image encryption scheme based on an improved memristive neuron chaotic system","authors":"Yanzhang Wang","doi":"10.1088/1402-4896/ad76e5","DOIUrl":"https://doi.org/10.1088/1402-4896/ad76e5","url":null,"abstract":"With fast-developing Internet and communication, the security transmission of image in network has become a research highlight. So far, researchers have designed a lot of image encryption methods based on chaotic models, some of them are not secure enough. To enhance security of image transmission on the network, in this paper, an image encryption method is developed from a 3D memeristive FitzHugh-Nagumo (FHN) neuron. First, a 3D memeristive FHN model is obtained by connecting a memeristor into a 2D FHN model, and dynamics for 3D FHN model are estimated by applying phase diagrams, bifurcation and Lyapunov exponent. Then, an image encryption algorithm is proposed by using this 3D model. Finally, security of encryption algorithm is estimated. Simulation results confirm the effectiveness of encryption scheme.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"26 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad7338
Yuxuan Chen, Yongzheng Sun, Weijun Zhou, Xuefeng Qin, Qian Zhao, Yueke Wang and Ben-Xin Wang
A terahertz metamaterial structure consisting of two U-shaped split-ring resonators and a horizontal cut-line resonator is designed for realizing the electromagnetically induced transparency (EIT) effect and the Fano resonance effect. The genesis of the EIT and Fano resonance bifunctionality is illustrated by combining the near-field distribution analysis of transparent windows and transmission dips. Interestingly, the bifunctional dual-band transparency effect could transform into a single-functional single-band transparency effect when we change the position of the square metal sheet in the vertical direction of the composited terahertz metamaterial structure. In addition, based on the high-quality factor of Fano resonance response, the proposed bifunctional terahertz metamaterial device has good refractive index sensing sensitivity. These results indicate that our proposed terahertz metamaterial can provide guidance for the design of subsequent multifunctional and integrated metamaterials and optoelectronic devices.
为实现电磁诱导透明（EIT）效应和法诺共振效应，设计了一种由两个 U 形分裂环谐振器和一个水平切割线谐振器组成的太赫兹超材料结构。通过结合透明窗口和透射凹陷的近场分布分析，说明了电磁诱导透明效应和法诺共振双功能的成因。有趣的是，当我们改变方形金属片在复合太赫兹超材料结构垂直方向上的位置时，双功能双波段透明效应可转化为单功能单波段透明效应。此外，基于法诺共振响应的高质量因子，所提出的双功能太赫兹超材料器件具有良好的折射率传感灵敏度。这些结果表明，我们提出的太赫兹超材料可为后续多功能集成超材料和光电器件的设计提供指导。
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Pub Date : 2024-09-11DOI: 10.1088/1402-4896/ad76e6
Tianyi Mao, Lei Liang, Caijie Gao, Chuanzhen Bian, Dongmiao Wang, Shujin Zhu and Xiubin Dai
Coded aperture cone-beam computed tomography (CBCT) represents a crucial method for acquiring high-fidelity three-dimensional (3D) tomographic images while reducing radiation exposure. However, projections are non-uniformly and discontinuously sampled with the coded apertures placed in front of the x-ray source, leading to very small reconstruction scale and time-intensive iterations. In this study, an alternative approach to reconstruct coded aperture CBCT based on generative adversarial U-net is proposed to effectively and efficiently reconstruct large scale 3D CBCT images. Our method entails predicting complete and uniform projections from incomplete and non-uniform coded projections, enabling the requirement of continuity for the use of analytical algorithms in 3D image reconstruction. This novel technique effectively mitigates the traditional trade-off between image fidelity and computational complexity inherent in conventional coded aperture CBCT reconstruction methods. Our experimental results, conducted using clinical datasets comprising CBCT images from 102 patients at Nanjing Medical University, demonstrate that high-quality CBCT images with voxel dimensions of 400 × 400 × 400 can be reconstructed within 35 s, even when 95% of projections are blocked, yielding images with PSNR values exceeding 25dB and SSIM values surpassing 0.85.
{"title":"Effective and efficient coded aperture cone-beam computed tomography via generative adversarial U-Net","authors":"Tianyi Mao, Lei Liang, Caijie Gao, Chuanzhen Bian, Dongmiao Wang, Shujin Zhu and Xiubin Dai","doi":"10.1088/1402-4896/ad76e6","DOIUrl":"https://doi.org/10.1088/1402-4896/ad76e6","url":null,"abstract":"Coded aperture cone-beam computed tomography (CBCT) represents a crucial method for acquiring high-fidelity three-dimensional (3D) tomographic images while reducing radiation exposure. However, projections are non-uniformly and discontinuously sampled with the coded apertures placed in front of the x-ray source, leading to very small reconstruction scale and time-intensive iterations. In this study, an alternative approach to reconstruct coded aperture CBCT based on generative adversarial U-net is proposed to effectively and efficiently reconstruct large scale 3D CBCT images. Our method entails predicting complete and uniform projections from incomplete and non-uniform coded projections, enabling the requirement of continuity for the use of analytical algorithms in 3D image reconstruction. This novel technique effectively mitigates the traditional trade-off between image fidelity and computational complexity inherent in conventional coded aperture CBCT reconstruction methods. Our experimental results, conducted using clinical datasets comprising CBCT images from 102 patients at Nanjing Medical University, demonstrate that high-quality CBCT images with voxel dimensions of 400 × 400 × 400 can be reconstructed within 35 s, even when 95% of projections are blocked, yielding images with PSNR values exceeding 25dB and SSIM values surpassing 0.85.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":"81 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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