Effect of composition on steady state and transient photoconductivity in isocoordinated In<Subscript>x</Subscript>Sb<Subscript>30−x</Subscript>Se<Subscript>70</Subscript> (0 ≤ x ≤ 25) chalcogenide films

The study of steady state and transient photocurrent measurement provide important information about carrier generation and recombination phenomena in various semiconducting systems for photo-sensor device applications. In the present work, the composition dependent analysis of photocurrents was studied for thermally evaporated Se-rich In_xSb_30?xSe₇₀ films of average thickness 800 nm. The indirect optical gap has been calculated from the transmission and reflection data and the variation of molecular units was studied from the Raman spectroscopy. The initial rise of photocurrent sharply to approach a steady state value during illumination and fast decay to a constant persistent current after stopping the illumination has been observed. The intensity dependence of photocurrent obeys the power law I_Ph?=?F^γ, where the value of exponent tells about the recombination process. The decay of photocurrent has been fitted with stretched exponential function for different compositions and at different light intensities. These results are important for the development of low cost photo absorbers for solar cell applications and visible region responsive photo sensor devices.     

Optimal Automatic Generation Control of Asynchronous Power Systems Using Output Feedback Control Strategy with Dynamic Participation of Wind Turbines

Abstract—This article presents the design of optimal output feedback automatic generation control regulators for an interconnected power system with dynamic participation of doubly fed induction generator based wind turbines. The power systems consist of plants with hydro-thermal turbines and are interconnected via parallel AC/DC links. Efforts have been made to propose optimal automatic generation control regulators based on feedback of output state variables, which are easily accessible and available for the measurement. The designed optimal output feedback automatic generation control regulators are implemented, and the system dynamic responses for various system states are obtained considering 1% load perturbation in one of the areas. The dynamic performance is compared with that obtained with optimal automatic generation control regulators designed using full state vector feedback. The pattern of closed-loop eigenvalues is also determined to test the system stability.     

JADE平台粒子群算法在环境经济调度中的应用

在环境经济调度模型中,为同时降低火电机组的燃料成本和污染气体排放量进行多目标优化,模型引入阀点效应并考虑网损,在满足功率平衡和出力限制的前提下,采用一种基于JADE平台下的粒子群多目标优化算法对模型进行求解。算法吸收了粒子群算法的进化机制,将Pareto占优策略和拥挤距离相结合并应用在粒子群算法中,添加了动态惯性权重特性和小概率变异,提高了算法全局搜索能力。在JADE平台下搭建算法模型,并运用IEEE-30节点6机组和IEEE-118节点40机组的标准测试系统进行仿真,结果表明该算法提高了系统的计算速度,改进了算法的并行性,更适合求解大规模复杂系统。     

Facile Synthesis of Ferrocene-Based Polyamides and Their Organic Analogues Terpolyamides: Influence of Aliphatic and Aromatic Sequences on Physico-Chemical Characteristics

Efforts have been devoted to synthesize and characterize processable polymers with desired properties. Herein, four different series of aromatic and aliphatic terpolyamides were prepared via solution phase polycondensation of 4,4′-oxydianiline and hexamethylenediamine (HMDA) with various diacids chlorides (isophthalyol dichloride, terepthalyol dichloride, 1, 1′-ferrocene dicarboxylic acid chloride and trans-azobenzene-4, 4′-dicarbonyl chloride). The structural, morphological and physico-chemical nature of as prepared polymers was explored by Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal analysis (TGA and DSC), and wide-angle x-ray diffraction. Moreover, an aliphatic diamine was incorporated in varying concentration as a flexible methylene spacer and the effect of its concentration on the properties of polyamides was also studied. Changes in various physico-chemical properties such as solubility, inherent viscosity, surface morphology and flame retarding behaviour were investigated. Marked difference in morphology and solubility was observed with the change in the ratio of segments in the chain. Inherent viscosities of polymers ranged from 1.8052–1.6274 dl/g indicating reasonably moderate molecular weights. Interestingly, ferrocene based aromatic polymers were more thermally stable (T_g 260 °C, T_i 310 °C, T_h 525 °C, T_f 720 °C, for PF₀), and also found to exhibit best flame retarding behavior (limiting oxygen index value for PF₀is LOI 33.15%).

     

Silicon Application Enhances the Photosynthetic Pigments and Phenolic/Flavonoid Content by Modulating the Phenylpropanoid Pathway in Common Buckwheat under Aluminium Stress

Silicon - Silicon (Si) is very effective in the amelioration of heavy metal (HM) stress in different crop plants. This investigation was conducted to assess the protective role of Si in modulating...     

发电厂电解水制氢设备调试及运行

氢气作为冷却介质性质上具有独特优势,300MW及以上发电机组多采用氢气冷却。自电厂的辅助系统中有了氢系统,其最核心的部分制氢站便成为电厂安全经济运行的重要组成。新建机组制氢站的调试为机组投运前的必要环节。介绍了制氢站的设备构成、调试步序、运行操作、安全事项并提出一些需要注意的问题进行讨论。     

Novel one‐step synthesis of acrylonitrile butadiene rubber/bentonite nanocomposites with (3‐Mercaptopropyl)trimethoxysilane as a compatilizer

Acrylonitrile butadiene rubber (NBR)/bentonite (Bt) nanocomposites were synthesized by an one‐step method in NBR latex with (3‐Mercaptopropyl)trimethoxysilane (MPTMS) as a compatilizer. The nanocomposites were compounded with curing additives and then vulcanized. The prepared vulcanizates were characterized by Fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction (XRD). The curing properties and mechanical properties were also investigated. The thermal properties were studied with thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology was investigated by field emission‐scanning electron microscopy (FE‐SEM). By swelling test, the swelling ratio and the crosslinking density were achieved. The hydrolyzation and condensation of MPTMS was identified by FTIR while the intercalated/exfoliated structure of Bt was determined by XRD. It was evident that the mechanical properties of the nanocomposites were significantly improved compared with the neat NBR. The well‐dispersed bentonite particles and effects of MPTMS were supported by the images from FE‐SEM. The results of TGA showed that the fastest weight‐loss temperature (T_max) was elevated by over 10°C for the nanocomposites compared with the neat NBR, indicating an enhanced thermal stability. By swelling test, the swelling ratio was determined, decreased to 139% for the optimized NBR/MPTMS/Bt nanocomposites compared with 210% for neat NBR. POLYM. COMPOS., 36:1693–1702, 2015. © 2014 Society of Plastics Engineers     

水平井水压致裂裂缝非平面扩展模型研究

水平井筒附近应力场分布复杂,往往造成水力裂缝转向,但目前对于水平井筒附近水力裂缝空间转向规律的认识还不够深入。为了研究水平井筒附近水力裂缝的三维延伸规律,基于最大拉伸应力准则和拉格朗日极值法建立了水平井筒附近水力裂缝空间转向模型,用于分析三向地应力和井筒内压作用下水平井筒水力裂缝的起裂位置和扩展形状。根据此模型,编制了数值计算程序。针对所建立的理论模型,在真三轴水力压裂模拟装置上采用岩石试样进行了物理模拟,模型计算结果与物理模拟结果基本一致。通过模拟计算和物理试验,得到了井筒附近水力压裂裂缝空间转向的基本规律。研究结果表明,水平井井筒附近水力裂缝的空间转向确实存在,裂缝转向前的距离随井筒方位角增加而增加,但增加幅度大致在3倍井筒直径的范围内。     

新型联合变换相关器光学系统设计

以往联合变换相关器的光学系统结构是一支光路反馈,实时性差且体积大。针对其缺点,设计了一种具有双光路的联合变换相关器。其中,最主要的特点是傅里叶透镜组与准直扩束系统共用同一片正透镜。改进后的装置可以清晰地探测到相关点,并具有体积小的特点。