具有前置公用工程的换热器网络的通用解法

本文在罗行等人提出的分级超结构换热器网络的通用解的基础上,提出一种将热冷公用工程放置于换热器网络每一级的冷热流体之前的带分流的分级超结构换热器网络数学模型,并根据这种新型的模型推导出换热器网络的出口温度和每一级流股节点的温度的计算公式,从而增强了分级超结构换热器网络模型的适用性.最后用实例证明所提出的数学模型的正确性.     

坝前淤泥土与新填坝体接触面抗剪强度试验研究及工程应用

坝前淤泥面与新填筑坝体接触面是"坝前淤泥面加坝"技术的薄弱环节.为了探究不同工况下淤泥坝基、新填筑坝体,以及淤泥土-新填土接触面的剪切强度特性,以宁夏南部山区西吉县南川水库坝前淤泥面加坝工程为研究对象,通过常规应变式直剪仪、改进常规应变式直剪仪分别进行剪切试验,分析了淤泥土含水率和压实度变化时,淤泥土、新填土、淤泥土-...     

129Xe30+与Au作用激发的Au M-X射线 与Xe L-X射线

探测了动能为1.0——7.0 MeV的¹²⁹Xe³⁰⁺ 入射Au表面产生的X射线谱. 实验结果表明, 入射离子动能较高时, 不仅激发出很强的Au的M-X射线, 还激发出了Xe的L-X射线, 且X射线产额与入射离子动能有强相关性. 分析了X射线产额与入射离子动能的关系.     

Performance of La2O3/InAlN/GaN metal—oxide—semiconductor high electron mobility transistors

We report on the performance of La2O3/InAlN/GaN metal-oxide-semiconductor high electron mobility transistors(MOSHEMTs) and InAlN/GaN high electron mobility transistors(HEMTs).The MOSHEMT presents a maximum drain current of 961 mA/mm at Vgs = 4 V and a maximum transconductance of 130 mS/mm compared with 710 mA/mm at Vgs = 1 V and 131 mS/mm for the HEMT device,while the gate leakage current in the reverse direction could be reduced by four orders of magnitude.Compared with the HEMT device of a similar geometry,MOSHEMT presents a large gate voltage swing and negligible current collapse.     

轮背空腔-密封气对CAES向心涡轮变工况流动损失的影响

本文以国内首套MW级压缩空气储能(CAES)系统末级向心涡轮为研究对象,通过数值模拟分析了变工况条件下轮背空腔-密封气对等熵效率和流场结构的影响.结果表明:在求解中考虑轮背空腔-密封气结构能够使等熵效率数值解的偏差减小0.7%;随涡轮进口压力增加,轮背空腔泄漏流由叶片吸力面中部叶高区域逐渐向轮毂转移,流动损失先增加后减小;合理降低轮背空腔泄漏气体的轴向速度,能够减弱轮背空腔-密封气结构对等熵效率的负面影响,使向心涡轮在较宽的变工况范围内都保持高效运行.     

500—4250eV电子对CO2的散射全截面绝对测量

对中能电子与二氧化碳分子碰撞的散射全截面测量，给出５００－４２５０ｅＶ电子对ＣＯ２的绝对散射全截面。对测量结果作了曲线拟合，并与已有的实验和理论结果进行了比较     

Discriminant Analysis of the Nutritional Components between Organic Eggs and Conventional Eggs: A 1H NMR-Based Metabolomics Study

The difference of nutrient composition between organic eggs and conventional eggs has always been a concern of people. In this study, ¹H nuclear magnetic resonance (NMR) technique combined with multivariate statistical analyses was conducted to identify the metabolite different in egg yolk and egg white in order to reveal the nutritional components information between organic and conventional eggs. The results showed that the nutrient content and composition characteristics were different between organic and conventional eggs, among which the content of glucose, putrescine, amino acids and their derivatives were found higher in the organic eggs yolk, while phospholipids were demonstrated higher in conventional eggs yolk. Organic acid, alcohol, amine, choline and amino acids were higher in conventional eggs white, but glucose and lactate in organic egg were higher. Our study demonstrated that there are more nutritive components and higher nutritional value in organic eggs than conventional eggs, especially for the growth and development of infants and young children, and conventional eggs have more advantages in promoting lipid metabolism, preventing fatty liver, and reducing serum cholesterol. Eggs have important nutritional value to human body, and these two kinds of eggs can be selected according to the actual nutrient needs.     

Ultrafast multiplex CARS investigation of vibrational characteristics in chloroform and PMMA

This paper demonstrates the femtosecond time-resolved coherent anti-Stokes Raman scattering by using folded BOXCARS geometry where an ultrashort broadband coherent white light continuum was used as Stokes pulse, and carries out the non-contact detection at long distance. The CARS signal is so easy to be detected that it can be seen even by nude eye. The C--H bonds of chloroform or PMMA were detected and the vibration modes belonging to the side chain and the main chain in PMMA were also compared. Their vibrational characteristics involved decay process and quantum beating were discussed. This modified CARS experimental technique could make up the deficiency of traditional CARS technique.     

碳纳米锥吸附Na的第一性原理计算

本文采用第一性原理计算结合从头算分子动力学的方法,研究了碳纳米锥(CNC)、B和N掺杂碳纳米锥(B-CNC和N-CNC)的稳定性,结果表明CNC、B-CNC和N-CNC均可以稳定存在.在此基础上分别研究了Na原子在CNC、B-CNC和N-CNC上的吸附行为.结果表明：1) Na原子在CNC五元碳环中心顶部位置的吸附最强,吸附能为-2.52 eV. CNC的能隙(Eg)为1.96 eV. 2) B和N掺杂CNC后,B-CNC和N-CNC的导电性均显著增强. 3)与CNC相比,Na原子在B-CNC上的吸附增强,而在N-CNC上的吸附则显著减弱.这表明B-CNC有望作为Na离子电池的负极材料.本文的研究结果对以CNC为负极材料的Na离子电池的研究提供了理论指导.