综合考虑水平和竖向地震作用的边坡稳定数方法

基于泰勒稳定数方法的拟静力分析是土坡地震稳定分析方法之一,该方法可以考虑水平地震作用得出地震作用下土坡的安全系数,但忽略了竖向地震作用的影响.为同时考虑水平和竖向地震作用,在前人工作的基础上,通过理论分析和公式推导,本文建立了一个能够同时考虑水平地震作用和竖向地震作用的解析公式,形成了改进的泰勒稳定图方法和计算流程.本...     

采用FPGA的动力锂电池内阻智能检测装置

为了实现对动力锂电池内阻的高精度检测,通过对锂电池内部结构和工作原理进行分析,建立了等效电路模型,并采用交流注入法设计了电池内阻在线智能检测装置。将微小的交变激励电流信号施加在电池两端,同时利用在FPGA平台上设计的正交锁相放大电路测量电池两端产生的响应电压信号,并通过引入圆周模式的CORDIC算法实现矢量运算,大幅提升了数据处理速度,最后根据欧姆定律计算出电池内阻的阻抗幅值和相位角。实验结果表明:设计的内阻智能检测装置能够方便测量出电池在各频段的阻抗谱,且具有较高的测量精度和稳定度,平均误差仅为0.231%,最大偏差也仅为0.452%,可为新能源汽车动力电池的健康诊断提供可靠的技术保障。     

Evolution of non-phosphine solvents in colloidal synthesis of I-III-VI2 and I2-II-IV-VI4 group semiconductor nanomaterials – Current status

The concepts of new synthetic ideas and their implementation in the synthesis of semiconductor nanomaterials have been a subject of interest in recent years. Influence of solvents on the properties of nanomaterials is an important area being pursued extensively and need better understanding to move ahead with new innovations. The selective role of solvents is an indispensable criteria in order to achieve semiconductor nanomaterials with excellent physical and chemical properties. By selecting a suitable solvent system, the morphology, phase, size as well as the optical properties of the resultant nanomaterials could be precisely tuned. This makes a great interest in colloidal chemistry to utilize them for the synthesis of various kinds of nanostructures. Most of the recently emerging synthesis methods of I-III-VI₂ and I₂-II-IV-VI₄ group semiconductor nanomaterials are based on thermolysis of metal precursors in non-phosphine solvents. The composition and the crystallographic phase of the nanoparticles can be varied by carefully choosing suitable non-phosphine solvents. Hence, the role of non-phosphine solvents in determining the structural and optical properties of the semiconductor nanoparticles is crucial. The present review summarizes the active role of non-phosphine solvents in the crystal structure, morphology and other properties of I-III-VI₂ and I₂-II-IV-VI₄ group semiconductor nanomaterials. The recent interesting results on the developments of this subject and fundamental background literature have been discussed elaborately.     

Enhanced performance in inverted polymer solar cells employing microwave-annealed sol-gel ZnO as electron transport layers

In this work, we propose a facile microwave-assisted approach for annealing sol-gel derived ZnO films to serve as electron transport layers (ETLs) for inverted bulk heterojunction polymer solar cells. We have demonstrated an impressive enhancement in performance for devices based on a poly (3-hexylthiophene) (P3HT): (6,6)-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) system employing the microwave-annealed ZnO (ZnO (MW)) ETLs in comparison to the cases using the conventional hotplate-annealed ZnO (ZnO (HP)) ones. The better electron transport in the device with the ZnO (MW) ETL is mainly ascribed to the preferable interfacial contact as evidenced by the morphology characteristics. Furthermore, the comprehensive analyses conducted from the light intensity dependent photocurrent and photovoltage measurements, the capacitance-voltage characteristics, and the alternating current impedance spectra suggest that the utilization of the ZnO (MW) ETLs can effectively suppress trap-assisted recombination as well as charge accumulation at the interface between P3HT: PC₆₁BM layers and ZnO layers, which is responsible for the enhanced device performance.     

Orthogonally weaved silver nanowire networks for very efficient organic optoelectronic devices

We demonstrate a simple but effective method to control the orientation of silver nanowires (AgNWs). Shear-flow-induced AgNW preferable orientation is realized by judiciously controlling the process parameters in the bar-coating method. This controllability of the NW direction enables the formation of AgNW cross-linking networks for transparent conductive electrode (TCE) applications. We experimentally demonstrate that the orthogonally weaved AgNW networks possess predominant advantages of lower percolation limit, higher transmission, and lower sheet resistance compared with the randomly orientated AgNW counterparts. The phenomenon is also confirmed with theoretical calculation by the Monte Carlo method. These high-quality AgNW TCEs exhibit a high transmittance of ∼94% with a sheet resistance of ∼20 Ω/sq, which meet the requirements of modern optoelectronic devices. Very efficient organic light-emitting diodes (OLEDs) and organic solar cells (OSCs) prepared by these AgNW TCEs are demonstrated. The OLED exhibits exceptionally high luminance efficiency, power efficacy, and external quantum efficiency of 92 cd/A, 111 lm/W, and 26.8%, respectively. The OSCs also deliver a high power conversion efficiency of up to 7.5%.     

混合同余法产生随机噪声的FPGA实现

在电子对抗领域,利用FPGA产生伪随机序列模拟噪声源的方法,可为实现各种噪声干扰带来便利。文中设计了基于混合同余法和中心极限定理产生随机噪声的FPGA实现方法。算法上对传统混合同余法进行了简化,避免了FPGA实现时大量的乘除运算。测试结果表明,该方法不仅有效可行,且简捷高效,生成的伪随机数具有周期、均值、方差等关键参数灵活可控,概率分布类型可变的特点,可为各种噪声干扰提供不同的噪声样本。     

基于回溯的最大频繁项集挖掘算法

针对Apriori类算法多次扫描数据库和FP-tree类算法需要构建大量条件模式树的问题,文中提出了挖掘最大频繁项集的GBMFI算法。采用垂直格式存储事务数据库,以枚举树为基础,利用子集非频繁性质和父子节点支持度信息在搜索过程中对枚举树进行剪枝,最终得到最大频繁项集。通过实验对比,结果证明了算法的有效性,尤其适用于稀疏数据集。     

消减气流脉动的机理及其对计量误差的影响

在天然气流量测量中常常遇到脉动流的干扰。本文从理论上分析了消减气流脉动的机理,阐述了消减脉动流对计量误差的影响,并指出消减脉动流的最佳方法。     

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为筹集天然气工业发展急需的资金,本文提出在天然气价格未全面调整前,对超包干天然气实行议价,随行就市,直接受市场调节。本文对这一办法进行了可行性分析,并列出超产气议价的幅度的计算方法,供决策参考。     

EVALUATION OF MALTING QUALITY IN A BARLEY BREEDING PROGRAMME USE OF α-AMYLASE AND β-GLUCAN LEVLES IN MALT AS PRESELECTION TOOLS

Analysis according to the EBC protocol, immunological determination of a α-amylase and estimation of malt β-glucan using the Calcofluor-FIA method, were used to screen 327 barley breeding lines for malting quality. The results obtained with the α-amylase and β-glucan methods are highly correlated to the important malt quality paramters: extract yield and β-glucan content in the wort. It is recommended that either of the two methods, which are simple to perform are used as prescreening tools in breeding programmes for malting barley.