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Electrical Analysis of Indium Deep Levels Effects on Kink Phenomena of Silicon NMOSFETs 铟深能级对硅nmosfet扭结现象影响的电学分析
Pub Date : 2014-02-27 DOI: 10.4236/WJNSE.2014.41002
Abdelaali Fargi, N. Hizem, A. Kalboussi, A. Souifi
Several methods of characterization of trap levels like I-V, C-V and transient spectroscopy (DLTS) were used to determine the accurate values of the activation energies of traps present in N+P junctions obtained after retrograde profile implantation of indium and boron on silicon. Four main traps located at Ev + 0.15 eV, Ev + 0.21 eV, Ev + 0.28 eV and Ev + 0.46 eV are reported. Shallow levels are also calculated from I-V characteristics. Concurrently, indium channel doped NMOSFETs are investigated showing the kink phenomenon. In order to discuss the relationship between the kink effect and the active indium trap level situated at 0.16 eV, the transient effects are studied by varying the integration time and the temperature. The effects of substrate polarization are also carried out showing the reduction of the kink with the bulk positive polarization.
利用I-V、C-V和瞬态光谱(dts)等几种表征陷阱能级的方法,确定了铟和硼在硅上逆行注入后N+P结中陷阱活化能的准确值。四个主要的陷阱分别位于Ev + 0.15 Ev, Ev + 0.21 Ev, Ev + 0.28 Ev和Ev + 0.46 Ev。浅电平也从I-V特性计算。同时,研究了掺杂铟沟道的nmosfet,发现了扭结现象。为了探讨结扭效应与处于0.16 eV的活性铟阱能级之间的关系,通过改变积分时间和温度研究了结扭效应的瞬态效应。基片极化的影响也表明,随着本体正极化的增加,扭结减少。
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引用次数: 2
Study of Physical, Chemical and Morphological Alterations of Smectite Clay upon Activation and Functionalization via the Acid Treatment 蒙脱石粘土经酸处理活化和功能化后的物理、化学和形态变化研究
Pub Date : 2013-12-05 DOI: 10.4236/WJNSE.2013.34019
M. T. Angaji, A. Zinali, N. Qazvini
The present study was carried out on the effect of acid leaching on the modification and structure alteration of montmorillonite. A nanostructured, activated material was prepared by selective leaching of pure smectite clay with different concentrations of sulfuric acid (1 - 10 N/L) at 85°C for 120 min using a solid/liquid ratio of 1:20 and a reflux system. The Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-Ray diffraction (XRD) techniques were used for the characterization and study of the acid-treated montmorillonite clay. Chemical structure of specimens was distinguished by FTIR. The results showed that the formation of Si-OH bonds and leaching of Al3+ ions increased progressively with severity of the acid treatment. As the FTIR studies indicated, acid treatment led to the removal of the octahedral Al3+ cations and an increase in the Si-OH bonds. The morphological alteration of the untreated and treated montmorillonite was investigated by using TEM and SEM. X-ray fluorescence (XRF) analysis revealed a considerable decrease in the relative content of Al by increasing the acid strength. Moreover, the XRD results showed that the treatment using highly concentrated acid resulted in the formation of an amorphous silica phase.
研究了酸浸对蒙脱土改性和结构改变的影响。用不同浓度的硫酸(1 - 10 N/L)在85℃条件下,以1:20的固液比和回流系统选择性浸出纯蒙脱石粘土120 min,制备了纳米结构的活性材料。采用傅里叶变换红外(FTIR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和x射线衍射(XRD)等技术对酸处理蒙脱土进行了表征和研究。用红外光谱分析了样品的化学结构。结果表明:Si-OH键的形成和Al3+离子的浸出随酸处理程度的增加而增加;FTIR研究表明,酸处理导致八面体Al3+阳离子的去除和Si-OH键的增加。采用透射电镜和扫描电镜对未经处理和处理过的蒙脱土的形貌变化进行了研究。x射线荧光(XRF)分析显示,通过增加酸强度,Al的相对含量显著降低。此外,XRD结果表明,高浓度酸处理导致了非晶硅相的形成。
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引用次数: 33
Carbonaceous Nanostructured Support Materials for Low Temperature Fuel Cell Electrocatalysts—A Review 低温燃料电池电催化剂用碳纳米结构支撑材料研究进展
Pub Date : 2013-12-05 DOI: 10.4236/WJNSE.2013.34017
M. Yaldagard, M. Jahanshahi, N. Seghatoleslami
Highly-dispersed platinum and platinum-based catalysts on a conductive support are commonly used as electrode materials in low-temperature fuel cells, particularly the hydrogen PEMFC and the direct methanol PEMFC. The performance and durability/stability of these catalysts strongly depend on the characteristics of the support. Catalysts supported on high surface area carbon black are widely used in low-temperature fuel cells. However, the corrosion of carbon black has been recognized as one of major causes of performance degradation and durability issues of low-temperature fuel cells under high-potential conditions. So the need for alternative supports with outstanding physical and mechanical properties to carry out the successful reaction in catalyst layer and give a longer lifetime for the electrocatalysts is inevitable. The emergence of nanotechnology and development of nanostructure materials in recent years has opened up new avenues of materials development for low-temperature fuel cells. This paper presents the performance with a variety of carbon-based nanostructured materials such as carbon nanotubes (CNT), carbon nanofibers (CNF), carbon aerogels, nanoplates of graphene, etc. So the present paper provides an overview of these nanostructured materials as low-temperature fuel cell catalyst supports. The improved characteristics of the nanostructured supports with respect to commercially used carbon black (Vulcan XC-72) and their effect on the electrochemical activity are highlighted. Additionally, it reviews the literature on the synthesis of nanostructured-supported Pt electrocatalysts for proton exchange membrane (PEM) fuel cell catalyst loading reducing through the improvement of catalyst utilization and activity. The features of each synthetic method were also discussed based on the morphology of the synthesized catalysts.
在导电载体上高度分散的铂和铂基催化剂通常用作低温燃料电池的电极材料,特别是氢PEMFC和直接甲醇PEMFC。这些催化剂的性能和耐久性/稳定性在很大程度上取决于载体的特性。高比表面积炭黑负载催化剂在低温燃料电池中有着广泛的应用。然而,炭黑的腐蚀已经被认为是低温燃料电池在高电位条件下性能下降和耐久性问题的主要原因之一。因此,需要具有优异物理和机械性能的替代载体来保证催化剂层反应的顺利进行,并延长电催化剂的使用寿命是必然的。近年来,纳米技术的出现和纳米结构材料的发展,为低温燃料电池材料的开发开辟了新的途径。本文介绍了碳纳米管(CNT)、碳纳米纤维(CNF)、碳气凝胶、石墨烯纳米板等多种碳基纳米结构材料的性能。因此,本文综述了这些纳米结构材料作为低温燃料电池催化剂载体的研究进展。重点介绍了纳米结构支架相对于商用炭黑(Vulcan XC-72)的改进特性及其对电化学活性的影响。此外,综述了通过提高催化剂的利用率和活性来减少质子交换膜(PEM)燃料电池催化剂负载的纳米结构负载Pt电催化剂的合成。根据所合成催化剂的形貌,讨论了各种合成方法的特点。
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引用次数: 47
Improvement of Open-Circuit Voltage in Organic Photovoltaic Cells with Chemically Modified Indium-Tin Oxide 化学修饰氧化铟锡改善有机光伏电池开路电压
Pub Date : 2013-12-05 DOI: 10.4236/WJNSE.2013.34016
Khayankhyarvaa Sarangerel, B. Delgertsetseg, N. Javkhlantugs, M. Sakomura, Chimed Ganzorig
The possibility of the increase in open-circuit voltage of organic photovoltaic cells based primarily indium-tin oxide (ITO)/rubrene/fullerene/Al structure by changing the work function of ITO anodes and Al cathodes was described in this work. To change built-in potential preferably in order to increase the open-circuit voltage, the work function of ITO should be increased and work function of Al should be decreased. The correlation between the change in work functions of electrodes and performance of the organic photovoltaic cells before and after surface modifications was examined in detail. The enhancement of open-circuit voltage depends on a function of work function change of both ITO and Al electrode. We could show that the built-in potential in the cells played an important role in open-circuit voltage.
本文描述了通过改变ITO阳极和Al阴极的功函数来提高主要基于氧化铟锡(ITO)/rubrene/fullerene/Al结构的有机光伏电池开路电压的可能性。为了更好地改变内置电位以提高开路电压,应增大ITO的功函数,减小Al的功函数。详细考察了表面修饰前后电极功函数的变化与有机光伏电池性能的关系。开路电压的提高取决于ITO和Al电极功函数的变化。我们可以证明细胞内的内置电位在开路电压中起重要作用。
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引用次数: 0
Density Functional Study of the Cluster Model of SnO 2 (110) Surface Modified by Benzoic Acids 苯甲酸修饰sno2(110)表面簇模型的密度泛函研究
Pub Date : 2013-09-06 DOI: 10.4236/WJNSE.2013.33007
Tegshjargal Khishigjargal, N. Javkhlantugs, Chimed Ganzorig, Youji Kurihara, M. Sakomura, K. Ueda
The properties of the modified surface of SnO2(110) with benzoic acid (Y-C6H4-COOH: Y is para position relative to -COOH group) derivatives were investigated using density functional theory. Zehner et al. mentioned that the modification of surface dipole moment made it possible to tune the work function of the system. The experiment of Ganzorig et al. showed that there was a linear relationship between the dipole moment of the binding molecule and the work function change of the system using the modified surface of indium-tin oxide (ITO) with some benzoic acid derivatives. To elucidate the relation between the dipole moment of the molecule and the work function change, we investigated the modified surface of SnO2(110) using Sn7O14 cluster model which was embedded in the fixed point charges. On the modification of the surface, benzoic acid derivatives were bound to SnO2 surface. By changing the terminal group of benzoic acid with H, Cl, F, CF3 and CCl3, the work function changed and the dipole moment of the binding molecules of the modified SnO2(110) were evaluated. The results showed that there was a linear relationship between the dipole moment of the binding molecules and the work function changed. From this relation, the average value of the dipole moments of Sn-OOC linkage at the surface was also evaluated.
用密度泛函理论研究了苯甲酸(Y- c6h4 -COOH: Y为相对于-COOH基团的对位)衍生物修饰SnO2(110)表面的性能。Zehner等人提到,通过对表面偶极矩的修改,可以对系统的功函数进行调整。Ganzorig等人利用某些苯甲酸衍生物修饰氧化铟锡(ITO)表面,实验表明结合分子的偶极矩与体系的功函数变化之间存在线性关系。为了阐明分子偶极矩与功函数变化之间的关系,我们利用嵌入固定点电荷的Sn7O14簇模型研究了SnO2(110)的修饰表面。在表面改性方面,苯甲酸衍生物与SnO2表面结合。通过用H、Cl、F、CF3和CCl3改变苯甲酸的末端基团,改变了功函数,并对改性SnO2(110)结合分子的偶极矩进行了评价。结果表明,结合分子的偶极矩与功函数的变化呈线性关系。根据这一关系,计算了表面Sn-OOC链偶极矩的平均值。
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引用次数: 3
The Effects of Annealing Process on Dielectric and Piezoelectric Properties of BMT-Base Lead-Free Ceramics 退火工艺对bmt基无铅陶瓷介电和压电性能的影响
Pub Date : 2013-09-06 DOI: 10.4236/WJNSE.2013.33014
M. Ghasemifard, Meisam Daneshvar, M. Ghamari
By using nitric acid as the fuel, the lead-free ceramic of Ba(Ti1-x,Mgx)O3 (x = 0.31) was prepared by auto combustion method (ACM). To make a comparison, this ceramic was also prepared using mixed oxide method (MOM). By X-ray diffraction, the phase structures of two samples were studied, and the results showed that rising temperatures would reduce unwanted phases. The piezoelectric and electrical properties as a function of calcination and sintering temperatures were investigated. The results showed that the outstanding electrical properties were obtained for nanoceramic with this composition. The SEM image of the grain size was estimated around 2 micrometers, and the grain size increased with the increasing of sintering temperature for two samples. The curie temperature of the BMT-ACM was 126°C and it’s significantly larger than the curie temperature of BMT-MOM which was 118°C. The results of electrical properties emphasized that the synthesis optimum temperature for two samples was about 1200°C and it was the best temperature that led to improved properties such as dielectric constant, polarization and piezoelectric coefficients.
以硝酸为燃料,采用自燃烧法(ACM)制备了Ba(Ti1-x,Mgx)O3 (x = 0.31)无铅陶瓷。为了进行比较,还采用混合氧化物法制备了该陶瓷。通过x射线衍射研究了两种样品的相结构,结果表明温度升高会减少不需要的相。研究了煅烧温度和烧结温度对其压电性能和电学性能的影响。结果表明,该成分制备的纳米陶瓷具有优异的电学性能。SEM图像显示,两种样品的晶粒尺寸在2微米左右,晶粒尺寸随烧结温度的升高而增大。BMT-ACM的居里温度为126℃,明显高于BMT-MOM的118℃。电学性能分析结果表明,两种样品的最佳合成温度均在1200℃左右,该温度可提高材料的介电常数、极化系数和压电系数等性能。
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引用次数: 5
Controlled Release of Diclofenac Sodium from Silica-Chitosan Composites 二氧化硅-壳聚糖复合材料双氯芬酸钠的控释研究
Pub Date : 2013-09-06 DOI: 10.4236/WJNSE.2013.33010
R. Kozakevych, Y. Bolbukh, V. Tertykh
The release profiles of acidic form of diclofenac sodium adsorbed on mesoporous silicas (Silochrom and two samples of spherical silicas) were compared with the dissolution characteristics of the pure drug. Desorption of diclofenac sodium from impregnated silicas with various surface liophilicity and composites of silica with chitosan have been studied using rotating basket method in phosphate buffer, pH 6.8. Sedimentations of sodium diclofenac via adsorption and impregnation from alcohol solution on fumed silica and modified silicas with grafted aminopropyl and trimethylsilyl groups were carried out. Polymer-containing composites have been prepared by capsulation of silica particles with impregnated diclofenac sodium by protonated and deprotonated forms of chitosan. Effect of the silica surface nature on the active substance release rate was ascertained. Significant prolongation of diclofenac sodium release was detected in the case of application of hydrophobic silica as a carrier and protonated chitosan as a polymeric shell.
研究了酸性双氯芬酸钠在介孔二氧化硅(Silochrom和两种球形二氧化硅样品)上吸附的释放特性与纯药物的溶出特性。在pH为6.8的磷酸盐缓冲液中,用旋转筐法研究了不同表面亲油性浸渍二氧化硅和壳聚糖复合二氧化硅对双氯芬酸钠的解吸作用。研究了气相二氧化硅和接枝氨基丙基和三甲基硅基改性二氧化硅在醇溶液中吸附和浸渍双氯芬酸钠的沉降过程。用壳聚糖的质子化和去质子化形式将浸渍双氯芬酸钠包覆二氧化硅颗粒,制备了含聚合物复合材料。考察了二氧化硅表面性质对活性物质释放速率的影响。以疏水二氧化硅为载体,质子化壳聚糖为聚合物外壳,双氯芬酸钠的释放时间明显延长。
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引用次数: 29
Physical Properties of CrSb/InP(001): Effect of Interface in Half-Metallic CrSb/InP(001)的物理性质:半金属界面的影响
Pub Date : 2013-09-06 DOI: 10.4236/WJNSE.2013.33011
A. Boochani, S. Solymani, S. Rezaee, N. B. Nezafat, S. Tadayon, Amin Aminian
In this study, density functional theory in improved flat waves’ framework has been used. First of all, characterization, elastic and half-metallic properties of the CrSb-ZB compound at (GGA & LDA) and GGA + U approximation are calculated. The elastic calculations indicate that the CrSb-ZB is a ductile material. However, the calculation of Deby temperature indicates that the CrSb-ZB is meta-stable. The half-metallicity character is also preserved at CrSb/InP (001) interface by GGA + U. The conduction band minimum (CBM) of CrSb in the minority spin case lies about 1.26 eV above that of GaSb, suggesting that the major spin can be injected into GaSb without being flipped to the conduction bands of the minor spin.
本研究将密度泛函理论应用于改进的平坦波框架。首先,计算了CrSb-ZB化合物在(GGA & LDA)和GGA + U近似下的表征、弹性和半金属性质。弹性计算表明,CrSb-ZB是一种延性材料。然而,代比温度的计算表明,CrSb-ZB是亚稳定的。GGA + u也保留了CrSb/InP(001)界面的半金属性特征。CrSb在少数自旋情况下的导带最小值(CBM)比GaSb高约1.26 eV,这表明主自旋可以注入GaSb而不被翻转到次要自旋的导带。
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引用次数: 2
Comparison of Acidic and Polymeric Agents in Synthesis of TiO 2 Nanoparticles via a Modified Sol-Gel Method 改性溶胶-凝胶法制备二氧化钛纳米颗粒的酸性与聚合剂的比较
Pub Date : 2013-09-06 DOI: 10.4236/WJNSE.2013.33012
M. Karimipour
TiO2 nano particles were synthesized in Rutile and Anatase phases by sol-gel method using two kind of complex agents, acidic (Citric Acid) and organic complex agent (acetyl acetone) at 400°C, 500°C, 650°C sintering temperatures. The structural analysis by XRD diffraction confirmed phase formation of titanium oxide. Particles sizes were determined by using Scherrer formula. TEM was employed to confirm nano particles formation. The size of nano particles as well as Phase formation can be controlled by the type of complex agent and sintering temperature. Acetyl Acetone causes a more crystalline structure and more uniformity of size distribution in 400°C sintering temperatures. Moreover, it results in obtaining single phase TiO2 nanoparticles at 400°C and 650°C sintering temperature. On the other hand, at high sintering temperature, the particles obtained from polymeric agent tend to agglomerate larger in size than the acidic product.
采用酸性配合剂(柠檬酸)和有机配合剂(乙酰丙酮),在400℃、500℃、650℃的烧结温度下,采用溶胶-凝胶法制备了金红石相和锐钛矿相的TiO2纳米颗粒。XRD衍射分析证实了氧化钛的相形成。采用Scherrer公式测定颗粒大小。透射电镜证实纳米颗粒的形成。复合剂的种类和烧结温度可以控制纳米颗粒的大小和相的形成。在400℃的烧结温度下,乙酰丙酮的结晶结构更强,尺寸分布更均匀。在400℃和650℃烧结温度下均可获得单相TiO2纳米颗粒。另一方面,在较高的烧结温度下,聚合剂得到的颗粒往往比酸性产物更大。
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引用次数: 5
Experimental Investigation of Drilling Fluid Performance as Nanoparticles 纳米颗粒钻井液性能的实验研究
Pub Date : 2013-09-06 DOI: 10.4236/WJNSE.2013.33008
J. Nasser, A. Jesil, T. Mohiuddin, Majid Al Ruqeshi, G. Devi, Shahjahan Mohataram
In this work, a drilling fluid recipe has been developed by using nanoparticles, to increase the efficiency of drilling operations for maximum accessibility to new & matured oil reserves and suited to various drilling conditions. The solution to severe drilling problems like pipe sticking, lost circulation, formation damage, erosion of borehole, thermal instability of drilling fluids and insufficient gel properties of the drilling fluids, lies in controlling and optimizing the rheology of the drilling fluid. The inefficiency of the drilling fluid in performing certain functions is mainly due to a lack in a particular rheological property. The performance of the clay composites water-based bentonite drilling mud in terms of its rheological behavior in drilling systems was investigated at various pressures and temperatures. It was found that temperature had a detrimental effect on the rheological properties. The behavior was investigated using synthesized nano bentonite water based drilling fluid. The fluid retained all the desired rheological properties at elevated temperatures and pressures, thus enhanced the possibility of its application in deep wells, where elevated temperatures and pressures were quite common.
在这项工作中,利用纳米颗粒开发了一种钻井液配方,以提高钻井作业效率,最大限度地开采新石油和成熟石油储量,并适应各种钻井条件。解决钻杆卡钻、漏失、地层破坏、井眼侵蚀、钻井液热不稳定、钻井液凝胶性不足等严重钻井问题的关键在于控制和优化钻井液的流变性。钻井液在执行某些功能方面的低效率主要是由于缺乏特定的流变性能。研究了粘土复合水基膨润土钻井液在不同压力和温度下在钻井体系中的流变特性。结果表明,温度对其流变性能有不利影响。采用合成的纳米膨润土水基钻井液对其性能进行了研究。该流体在高温高压下保持了所有所需的流变性能,从而提高了其在高温高压环境下的深井应用的可能性。
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引用次数: 100
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纳米科学与工程(英文)
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