离心泵快速启动过程外部特性的试验研究

介绍离心泵快速启动试验装置和试验方法,对一台出口直径为80 mm的小型管道离心泵进行试验研究,分别测试了试验泵的稳态性能和各项瞬态性能,比较分析了两者的区别。结果显示,启动过程中,离心泵的扬程紧跟转速到达最大值,转速稳定后的瞬态性能与稳态假设对应,流量和扬程的上升历程与管路阻力特性直接相关,而转速与其基本无关; 在启动初始阶段,无量纲扬程呈现很大值,继而迅速减小到低于稳态假设值,表现出明显的瞬态效应。     

电热泵用于蔬菜温室供热的经济性分析

现代化蔬菜温室是我国都市农业发展中的一个重要组成部分，目前这类温室的冬季加热均以燃煤方式为主．伴随着越加严重的城市环境污染，温室供热系统也面临着改造问题，需要引入清洁供热方式，热泵供热是其中的一种．本文以上海地区现代化蔬菜温室为研究对象，分析了蔬菜温室中使用电热泵供热的运行成本，并与燃煤供热方式进行了对比．就热泵供热系统在温室中的应用前景及可行性、经济性进行了分析，为热泵在温室供热系统中的应用提供了可参考依据．     

InAs/GaSb/AlSb resonant tunneling spin device concepts

We discuss device concepts for creating spin-polarized current sources without external magnetic fields, using non-magnetic 6.1 Å semiconductor resonant tunneling structures. Spin filters, spin pumps, and spin transistors that exploit structural and bulk inversion asymmetries will be examined.     

Theoretical and computational studies of vectorial processes in biomolecular systems

Efficient vectorial processes such as the transduction of bioenergy and signals are characteristics that strikingly distinguish living systems from inanimate materials. Recent developments in biophysical and biochemical techniques have provided new information about the structure, dynamics and interaction of biomolecules involved in vectorial life processes at multiple length and temporal scales. This wealth of data makes it possible to carry out theoretical and computational studied of key mechanistic questions associated with complex life processes at an unprecedented level. Using two “vectorial biomolecular machines”, myosin and cytochrome c oxidase, as examples, we discuss the identification of interesting and biologically relevant questions that require thorough theoretical analysis. Technical challenges and recent progress related to these theoretical investigations are briefly summarized     

Pulsed pump: Thermal effects in solid state lasers under super-Gaussian pulses

Solid state laser (SSL) powers can be realistically scaled when pumped by a real, efficient and multimode pulse. In this work, a fourth-order super-Gaussian pulse was assumed as a pump for SSL’s and a complete analytical expression for the thermal phase shift is given. Moreover, the focal length of thermal lens in paraxial ray approximation regime was studied. The results when applied to a Ti: sapphire crystal show an appreciable correction for abberation compared to a top-hat pulse.     

激光二极管泵浦的高重复频率Nd：YAG激光器

报道两个１．５Ｗ连续激光二极管端面泵浦的声光调ＱＮｄ：ＹＡＧ激光器，输出激光脉冲的最高重复频率为３０ｋＨｚ重复频率１ｋＨｚ时，最窄脉宽为１２ｎｓ，最高峰值功率为１２．１ｋＷ。     

半导体激光泵浦预激光锁模调Q固体激光器研究

报道半导体激光侧面泵浦预激光锁模调Ｑ的Ｎｄ：ＹＡＧ固体板条激光器，预激光锁模调Ｑ的激光脉冲宽度为３６ｐｓ，调Ｑ包纤各心的锁模单脉冲能量超过７μＪ，相应的峰值功率达２００ｋＷ。     

Thermodynamic properties of lithium chloride ammonia complexes for application inahigh-lifthigh temperature chemical heat pump

Ammonia absorption by and desorption from lithium chloride at different pressures has been studied using high-pressure differential scanning calorimetry, for application in a high-lift high temperature chemical heat pump. The measurements were performed under isobaric as well as under isothermal circumstances. Clausius–Clapeyron plots were constructed and used to calculate the thermodynamic parameters and to determine the stability regions of the different complexes. Controversies in literature as to the real existing phases are resolved.     

一种新的质子泵抑制剂苯并咪唑衍生物的合成与表征

以2-巯基苯并咪唑为原料,在碱性条件下与自制的盐酸2-氯甲基-4-(3-甲氧基丙氧基)-3-甲基吡啶缩合得2-{[4-(3-甲氧基丙氧基)-3-甲基吡啶-2-基]甲基硫}-1H-苯并咪唑,再经氧化、成盐反应生成产物2-{[4-(3-甲氧基丙氧基)-3-甲基吡啶-2-基]甲基亚硫酰基}-1H-苯并咪唑钠,总收率66%.此产物通过红外光谱、核磁共振、质谱表征加以确认.     

Application of capillary electrophoresis with different sample stacking strategies for the determination of a group of nonsteroidal anti-inflammatory drugs in the low microg x L(-1) concentration range

Several on-column sample preconcentration modes--large-volume sample stacking using the EOF pump (LVSEP), LVSEP with anion-selective exhaustive injection (LVSEP-ASEI) and field-amplified sample injection with sample matrix removal using the electroosmotic flow (EOF) pump (FAEP)--were used to analyze some nonsteroidal anti-inflammatory drugs (NSAIDs) by capillary electrophoresis, and then compared. Methanol was the background electrolyte solvent to suppress the EOF. The effect of the type and length of the solvent plug, and the sample injection time were investigated in FAEP to determine the conditions that provided the best response. LVSEP, LVSEP-ASEI, and FAEP improved the sensitivity of the peak area by 100-, 1200-, and 1800-fold, respectively. The methodology developed, in combination with solid-phase extraction (SPE), was applied to the analysis of water samples.