阳极氧化法制备TiO2纳米管及在直射式DSSC中的应用研究

采用磁控溅射技术在透明导电玻璃(FTO)的表面沉积一层钛薄膜,应用电化学阳极氧化法,在钛基体表面原位构建出致密、高长径比的二氧化钛纳米管阵列,将制得的TiO2纳米管作为光阳极制备直射式染料敏化太阳能电池(DSSC),并测试电池性能.结果表明:在阳极氧化电压为25V,NH4F电解液浓度为0.5ωt％条件下,可制备出结构规整有序的TiO2纳米管阵列,从而制得直射式染料敏化太阳能电池,在AM1.5,光强100mW/cm2的模拟太阳光光照条件下测试,开路电压Voc=0.82 V,短路电流Isc=8.19 mA·cm-2,填充因子FF=0.61,光电转换效率η=4.03％,比相同条件下钛片背光式DSSC提高了29.1％.     

TiO2薄膜电极光电转换性能的影响因素

采用溶胶-凝胶法在玻璃基体表面制备了不同粒径的TiO2薄膜和纳米SnO2/TiO2复合薄膜,将它们与不同对电极进行了光电转换性能测试.结果表明:氧化物薄膜电极经染料敏化、薄膜颗粒细化及薄膜复合化都有利于提高电极的光电转换性能.用汞溴红敏化后,粒径为25 nm的TiO2薄膜的光电转换性能提高了847倍;粒径为25 nm的TiO2薄膜的光电转换性能是粒径为136 nm的TiO2薄膜的5倍;粒径为25 nm的TiO2薄膜经粒径为27 nm的SnO2薄膜复合后,其光电转换性能提高了7.7%.     

太阳电池测试系统的研制

为了获得太阳电池的基本性能参数,研究太阳电池动态行为及光电转换机制。我们采用labview8.5语言和光脉冲技术,研制了一套太阳电池测试系统。该系统实现了I-V曲线、电荷提取、光电压衰减、光脉冲扰动瞬态的电池行为测试,可以获得太阳电池的开路电压、短路电流、填充因子、光电转换效率等基本性能参数以及电子扩散系数、电子寿命、电子扩散长度等微观性能参数。本系统已在染料敏化太阳电池研究中获得了重要实验结果。     

高度有序二氧化钛纳米管阵列太阳能材料研究取得新进展

二氧化钛作为一种性能优异的无机功能材料，在光电催化剂、染料敏化太阳能电池、自清洁、光解水等领域获得广泛研究，并取得巨大的进展。近年来发展的一种以阳极氧化的方法制备高度有序的TiO：纳米管阵列更成为国内外材料研究领域的热点。     

敏化工艺对硒化铅薄膜形貌和性能的影响

用醋酸铅、硒粉及亚硫酸硒钠为主要原料采用化学液相沉积的方法在玻璃衬底上制备出了一系列的硒化铅半导体薄膜材料,采用在有氧环境下对薄膜进行热处理来实现薄膜的敏化过程,用SEM、XRD、EDS和IR等分析手段对薄膜的形貌、结构以及性能进行了表征。当敏化温度低于375℃时薄膜晶粒尺寸变化不大,但表面O/(Se+Pb)原子比随敏化温度的升高而明显升高,同时薄膜结构有所变化。硒化铅薄膜经过敏化处理后具有了一定的光电特性,在光照条件下薄膜的电阻变化率在5%～10%左右。     

层状结构金属化合物薄膜的制备及表征

采用分析纯TiO2、Nb2O5和K2CO3粉末为原料，采用高温固相反应制备出具有层状结构的K4Nb6O17和K2Ti4O9粉末，经过湿磨和离心沉淀分离，用旋转涂敷法在石英玻璃基片表面制备K4Nb6O17和K2Ti4O9薄膜。对所制备K4Nb6O17薄膜进行H^ 离子交换和正丙胺层间插入反应，用XRD对所制备的粉末和薄膜进行了表征。结果表明：所制得的薄膜均具有层状结构，因此有希望用此方法制备半导体复合金属化合物光催化薄膜。     

简单包覆改性LiMn_2O_4正极材料在高温下的电化学性能

为了解决尖晶石锰酸锂(LiMn2O4)电池正极在高温下容量降低过快的问题,通过简单方法将NiO包覆到LiMn2O4粉体表面,并对包覆前后LiMn2O4粉体材料的结构、形貌和相应正极材料的电化学性能进行了研究。结果表明:NiO包覆LiMn2O4粉体后其晶体结构没有发生改变,表面呈现钟乳石状突起;与包覆前相比,NiO包覆LiMn2O4粉体后的正极材料的循环性能和倍率性能分别提高了8.79%和14.04%。     

沉淀包裹法制备Cu/α-Al2O3纳米复合粉体

以纳米Al2O3、CuSO4·5H2O和纳米铝粉为原料,采用非匀相沉淀工艺获得了纳米铜包裹α-Al2O3复合粉体;研究了反应温度和pH值对复合粉体成分及性能的影响;利用XRD、XPS、TG/DSC、Zeta电位和TEM等方法对复合粉体的成分、热学特性以及形貌特征进行了表征.结果表明采用反应温度为40℃、保温4 h的工艺条件,可以获得纳米铜颗粒包裹Al2O3纳米复合粉体,铜颗粒呈球形,尺寸为10 nm左右.     

基于Zn_2SiO_4:Mn的成像器件紫外增强薄膜制备及表征

在CCD、CMOS等硅基光电成像器件的光敏面镀下变频薄膜将紫外波段的光变为可见波段的光,可实现CCD、CMOS等硅基光电成像器件的紫外响应.考虑Zn2SiO4∶Mn粒子直径小,稳定性好,荧光量子效率高等优点,本文用"旋涂法"在石英基底上生成Zn2SiO4∶Mn紫外增强薄膜,并对其透射光谱、吸收光谱、激发光谱与发射光谱等光学性质进行分析.实验测得薄膜在300 nm以下透过率极低并具有很强的吸收,在300 nm以上透过率很高且吸收很弱;激发峰在260 nm,发射峰在525 nm,可以实现将紫外光转化为可见光.分析了Zn2SiO4∶Mn薄膜的均匀性、厚度、稳定性等物理性质对其变频性能的影响.实验结果表明,利用Zn2SiO4∶Mn薄膜可以有效增强CCD等光电器件的紫外响应,实现光电器件的紫外探测.     

基于等离激元热电子效应的光电晶体管制备及其特性

为了解决典型宽禁带半导体光电探测器件的工作波段限制材料禁带宽度的问题,对基于表面等离激元热电子效应的光电晶体管进行了制备和光电性能研究,提出一种采用重掺杂的硅片作为背栅极、二氧化硅(SiO_2)氧化层作为绝缘层,且能利用等离激元热电子效应的光电晶体管,有望实现响应光谱的调控。利用热退火方法在绝缘层表面修饰金纳米颗粒,并结合射频溅射、物理掩模和真空热蒸镀的方法实现了热电子效应铟镓锌氧化物(IGZO)光电晶体管。器件的光学和电学性能测试结果表明:修饰金纳米颗粒的光电晶体管在658nm红光入射下产生明显的光电响应,外加90V栅极偏压时,光电流提升约为2.2倍。金纳米颗粒修饰的等离激元热电子结构有效调控了该型晶体管的响应光谱范围,不受材料禁带宽度的限制,而且晶体管的背栅调控进一步放大光电流,提高了器件的量子效率。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....