Aspects of second-order velocity slip and radiation absorption on hydromagnetic stagnation point flow of Jeffrey fluid with chemical reaction

The present article describes the magnetohydrodynamic flow of a moving Jeffrey fluid along a convectively heated porous stretching surface with second-order velocity slip and radiation absorption effects. Furthermore, chemical reactions and viscous dissipation impacts are also taken into account. The governing equations are converted into dimensionless ordinary differential equations (ODEs) using appropriate similarity transformations. The highly nonlinear ODEs are solved numerically by employing a shooting technique based on the Runge–Kutta Cash–Karp formula. The figures are used to study the variations in temperature, velocity, and concentration profiles for several physical factors. The numerical values of the local skin friction, Sherwood number, and Nusselt number are explained and shown in tables. The analysis reveals that the velocity profile is enhanced for amplifying values of velocity ratio parameter and first-order velocity slip parameter. However, the temperature profile of Jeffrey nanofluid is highlighted w.r.t. Eckert number and radiation absorption parameter. This study may find significant applications in polymer production, food processing, instrumentation, combustion modeling, catalytic chemical reactors, and so on.     

含分布式电源并网特性的配电网重构策略

不同类型的分布式电源(distributed generation,DG)并网到配电系统后,分析在不同种类DG出力的影响下进行配电网合理的网络结构调整成为配电网优化重构技术的关键。本文提出了一种综合考虑不同类型DG并网方式及其特性的配电网重构方法模型。考虑不同类型的并网DG接口,研究相应的等效接入方式。根据配电网辐射状特点,以网损最优为目标,建立基于二阶锥规划的重构数学模型。利用标准配电系统进行算例仿真,与传统重构算法的效果对比,验证了本文所提重构模型的有效性和计算精度,能够高效提升运行的经济性与安全性。     

抑制直流偏移的改进型二阶广义积分器的锁频环设计

针对传统基于二阶广义积分器的锁频环(Second-Order Generalized Integrator Based Frequency Locked-Loop,SOGI-FLL)抗直流干扰能力不足的问题,提出一种能够抑制直流偏移的改进型SOGI-FLL设计方案。简要介绍了SOGI-FLL的结构,并量化分析了输入信号中直流分量对SOGI-FLL的锁频输出信号和正交信号对中β轴分量的影响。通过新增一条低通滤波通道,对SOGI-FLL进行结构改进,并结合锁频环结构推导传递函数进行频率特性分析,证明了该改进方案的有效性。利用PSCAD仿真软件,在含直流分量的电网环境下,通过设置多组SOGI-FLL和ESOGI-FLL的对比实验验证了所设计方案的正确性。     

Replicated piecewise stopping numbers and sequential analysis

For certain basic problems in sequential analysis,it is shown that a piecewise sequential methodology resting on replicated piecewise stopping numbers provides a natural estimate of the variance of the overall stopping variable without compromising much on the performancecharacteristics of the estimation rules.     

烟草抗PVYN突变株SN01的SRAP—PCR反应体系的建立与优化

采用正交试验对烟草抗PVYN突变株SN01幼嫩叶片的SRAP-PCR反应体系中5个主要因素（dNTPs、Mg2＋、TaqDNA聚合酶、引物和DNA）进行了优化以建立合适的SRAP反应体系。结果表明,在20μL的反应体系中,各因素的最佳加入量分别是：dNTPs（2．5mmol／L）3．2μL、Mg2＋（25mmol／L）1．6μL、TaqDNA聚合酶（2．5u／μL）0．16μL、引物（10μmaol／L）0．6gL、DNA模板120ng。对该SRAP—PCR反应程序中的退火温度和循环次数筛选表明,最佳退火温度为57℃,循环次数为35次。该优化体系的建立,为进一步对烟草抗PVYN突变株SN01的抗病基因研究提供了可靠基础。     

Relationships between PSII-independent hydrogen bioproduction and starch metabolism as evidenced from isolation of starch catabolism mutants in the green alga Chlamydomonas reinhardtii

Sulfur deprivation, which is considered as an efficient way to trigger long-term hydrogen photoproduction in unicellular green algae has two major effects: a decrease in PSII which allows anaerobiosis to be reached and carbohydrate (starch) storage. Starch metabolism has been proposed as one of the major factors of hydrogen production, particularly during the PSII-independent (or indirect) pathway. While starch biosynthesis has been characterized in the green alga Chlamydomonas reinhardtii, little remains known concerning starch degradation. In order to gain a better understanding of starch catabolism pathways and identify those steps likely to limit the starch-dependent hydrogen production, we have designed a genetic screening procedure aimed at isolating mutants of the green alga C. reinhardtii affected in starch mobilization. Using two different screening protocols, the first one based on aerobic starch degradation in the dark and the second one on anaerobic starch degradation in the light, eighteen mutants were isolated among a library of 15,000 insertion mutants, eight (std1-8) with the first screen and ten (sda1-10) with the second. Most of the mutant strains isolated in this study showed a reduction or a delay in the PSII-independent hydrogen production. Further characterization of these mutants should allow the identification of molecular determinants of starch-dependent hydrogen production and supply targets for future biotechnological improvements.     

耐高温耐高酒度醋酸菌突变株的选育

以从高温季节发酵良好的醋醅中，分离筛选出的N9、F17两株醋酸菌为出发菌株，经紫外线、硫酸二乙酯逐级诱变，分别获得编号为HNl5、HF6两株耐高温耐高酒度醋酸菌株。在培养温度40℃，培养基酒度12％（V／V）条件下，HN15酒精转化率为75％，HF6酒精转化率为70％。     

高Q腔中非简并双模Tavis－Cummings模型中原子布居及光场的性质

讨论了非简并双模光场与两个两能级原子相互作用的Ｔａｖｉｓ－Ｃｕｍｍｉｎｇｓ（Ｔ－Ｃ）模型中辐射场的相关特性和原子布居的演化。     

A New 1-V Second-Order Temperature-Compensated Current Reference

Current reference, a frequently encountered building block, finds extensive uses in numerous applications, ranging from the bandgap voltage reference to the bias circuit [1,2]. To achieve a temperature stable current in bipolar technology, a common and important approach is to compensate a current derived from VBE by a current based on △VBE. Another technique called “supply-following” is also available in bipolar process [3]. Although present works obtained good results with the employmen…     

Disconnection of the basolateral amygdala complex and nucleus accumbens impairs appetitive Pavlovian second-order conditioned responses.

There is considerable evidence that the basolateral complex of the amygdala (ABL) is involved in learning about the motivational value of otherwise neutral stimuli. The authors examined the role in this function of the ABL and one of its major efferent structures, the nucleus accumbens. Male Long-Evans rats received either sham, ipsilaterally. or contralaterally placed unilateral lesions of the ABL and accumbens and were trained in an appetitive Pavlovian second-order conditioning task. Sham-lesioned and ipsilaterally lesioned rats acquired the task normally, but contralaterally lesioned rats, in which the ABL and accumbens were functionally disconnected, failed to acquire second-order conditioned responses (although they did acquire second-order conditioned orienting responses). The results suggest that the ABL and accumbens are part of a system critical for processing information about learned motivational value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)