On the stability analysis of microscopic traffic car-following model: a case study

The stability analysis of the microscopic traffic car-following model is an important issue. The present paper systematically discusses the local stability and asymptotic stability of the car-following model; meanwhile, the corresponding Lyapunov stability is also proposed from the viewpoint of control. Moreover, taking the full velocity difference (FVD) car-following model as a case, the difference among the three stability analysis approaches and the simulation are conducted. Finally, the results reveal that it can improve the dynamic performance when keep the value of the gain factor k constant and increase the value of sensitivity coefficient of velocity difference λ; and so is it when it keeps the value of a sensitivity coefficient of velocity difference λ constant and increases the value of the gain factor k, while the value of the gain factor k is dominant in this process.     

An AlGaN/GaN HEMT with enhanced breakdown and near-zero breakdown voltage temperature coefficient

An AlGaN/GaN high-electron mobility transistor (HEMT) with a novel source-connected air-bridge field plate (AFP) is experimentally verified. The device features a metal field plate that jumps from the source over the gate region and lands between the gate and drain. When compared to a similar size HEMT device with conventional field plate (CFP) structure, the AFP not only minimizes the parasitic gate to source capacitance, but also exhibits higher OFF-state breakdown voltage and one order of magnitude lower drain leakage current. In a device with a gate to drain distance of 6 μm and a gate length of 0.8 μm, three times higher forward blocking voltage of 375 V was obtained at V_GS=-5 V. In contrast, a similar sized HEMT with CFP can only achieve a breakdown voltage no higher than 125 V using this process, regardless of device dimensions. Moreover, a temperature coefficient of 0 V/K for the breakdown voltage is observed. However, devices without field plate (no FP) and with optimized conventional field plate (CFP) exhibit breakdown voltage temperature coefficients of -0.113 V/K and -0.065 V/K, respectively.     

生物质气为燃料的燃料电池理论电动势计算

在以生物质气体为燃料的固体氧化物燃料电池体系中,通过热力学平衡分析编程计算出700-1200 K时气体中各物种例如H2、CO、CO2和CH4的平衡组成,从而得到以氧化钇稳定氧化锆(YSZ)为电解质的电池理论电动势．碳沉积对电动势有显著影响．通过计算可以推测比较适宜的操作温度和增湿条件．还计算了以掺杂氧化铈为电解质的电池电动势,相比氢气为燃料时,使用生物质气体导致的电动势的下降比使用YSZ为电解质的电池要小的多．     

光的散射定律及其证明

本文从完全新的角度出发,建立起散射介质的整体散射模型,从而发现了普遍适用的光的散射定律,并且开拓了测量介质散射率的新的研究领域。     

武汉市城郊农业的经济分析

根据我国大城市城郊农业的一般经济特征，分析了武汉市城郊农业的功能，特征及其发展的支撑条件和制约因素，并针对其未来发展提出了若干对策。     

Stereoselective synthesis of new conformationally restricted analogues of a potent CGRP receptor antagonist

[structures: see text] A stereocontrolled racemic synthesis of conformationally restricted analogues 2a and 2b of a potent CGRP receptor antagonist 1 by novel functionalization of 2-substituted octahydropyrido[1,2-a]pyrazin-6-ones is described. The new diastereoselective LDA-promoted alpha-nitration of intermediate lactams established the required trans-configuration in the desired products.     

Heterogeneous UV／Fenton catalytic degradation of wastewater containing phenol with Fe－Cu－Mn－Y catalyst

The heterogeneous UV/Fenton process with the appropriate amount of Fe-Mn-Cu-Y as catalyst was developed and various operation conditions for the degradation of phenol were evaluated. The results indicated that by using the heterogeneous UV/Fenton process, the CODer removal rate reached almost 100% for wastewater containing phenol. Compared with the homogeneous process, the developed catalyst could be used at wider pH range in the UV/Fenton process. Comparison of various heterogeneous process showed that heterogeneous UV/Fenton process was best. The heterogeneous UV/Fenton process with Fe-Mn-Cu-Y catalyst is highly efficient in degrading various organic pollutants.     

Scale-up of rifamycin B fermentation with Amycolatoposis mediterranei

Study of the effect of dissolved oxygen and shear stress on rifamycin B fermentation with A. mediterranei XC 9-25 showed that rifamycin B fermentation with Amycolatoposis mediterranei XC 9-25 needs high dissolved oxygen and is not very sensitive to shearing stress. The scale-up ofrifamycin B fermentation withA, mediterranei XC 9-25 from a shaking flask to a 15 L fermentor was realized by controlling the dissolved oxygen to above 25% of saturation in the fermentation process, and the potency of rifamycin B fermentation in the 15 L fermentor reached 10 g/L after 6-day batch fermentation. By continuously feeding glucose and ammonia in the fermentation process, the potency of rifamycin B fermentaion in the 15 L fermentor reached 18.67 g/L, which was 86.65% higher than that of batch fermentation. Based on the scale-up principle of constantly aerated agitation power per unit volume, the scale-up of rifamycin B fed-batch fermentation with continuous feed from a 15 L fermentor to a 7 m^3 fermentor and further to a 60 m^3 fermentor was realized successfully. The potency of rifamycin B fermentation in the 7 m^3 fermentor and in the 60 m^3 fermentor reached 17.25 g/L and 19.11 g/L, respectively.     

Optimization of polymer electrolytes for quasi-solidstate dye-sensitized solar cells

The dye-sensitized nanocrystalline TiO2 thin filmsolar cells (DSSCs) have attracted much attention since1990s[1— , due to their high light to electrical energy 4]conversion efficiency. So far, many studies have beenmade on the use of liquid electrolytes such as acetonitrile,3-methoxypropionitrile and a mixture of ethylene/pro-pylene carbonate (EC/PC) containing I? /I3 redox cou-?ple. A light to electrical energy conversion efficiency of7%— 12% has been obtained for DSSC using liquid e…     

论秦观词的语言美

秦观词素有美如春花的赞誉,这一美学特色毫无疑问主要体现在他词作的“天生好言语”上。本文着重对秦词语言的色彩美,音律美,灵动美和含蓄美的具体形态作了较为全面的观照,从而使我们对秦词的语言特色,有一个深入的体认。