覆盖亚临界到临界区的制冷工质物性快速算法

为了在亚临界到临界点这个大范围内保证制冷剂物性计算的快速、稳定、可逆,提出将整个数据区间划分成若干个子区间分别进行隐式拟合,并且保证相邻子区间连接点处的连续与光滑,以及通过求分析解从隐式方程中得到显式物性计算式的方法.以美国国家标准局开发的程序REFPROP6.01的计算结果作为数据源,以R410A为例对该方法做了验证.得出快速物性计算公式的应用范围为饱和温度-60℃至临界温度,与NIST REFPROP 6.01的计算结果进行比较表明,计算速度快1500倍,平均相对偏差小于0.01%.     

风冷热泵冷热水机组动态过程仿真

本文给出了风冷热泵冷热水机组动态过程模型。系统的高、低压段被分成制冷剂侧、管壁、以及水或空气侧三个控制容积。针对每个控制容积建立了质量和能量平衡的微分方程。由于压缩机、热力膨胀阀阀体、以及四通换向阀具有较小的热惯性,因而采用稳态模型描述压缩过程、膨胀过程、以及内泄露过程。膨胀阀感温包中的制冷剂温度对于蒸发器出口温度的延迟用一阶惯性环节来描述。通过“预测-校正”和“自适应步长”方法实现系统仿真。仿真结果与测试数据吻合良好。     

化学非平衡夸克-胶子物质中等质量双轻子的产生

研究了正在进行化学平衡的富重子夸克-胶子物质的双轻子产生，发现由于产生在RHIC能量 的化学非平衡的富重子夸克-胶子物质冷却慢和高的初始温度，导致中等质量双轻子产生重 大增强.因此，中等质量双轻子的增强可以是夸克-胶子物质形成的信号.同时，这个增强能 补偿由于初始夸克化学势增加引起的双轻子抑制，因而双轻子产额的抑制不再是夸克-胶子 物质产生的信号. 关键词： 化学非平衡夸克-胶子物质 热粲夸克 双轻子     

Theoretical study of the reaction of Sc with SCO in gas phase

In order to elucidate the mechanism of reaction M⁺ + SCO, both triplet and singlet potential energy surfaces (PESs) for the reaction of Sc⁺ + SCO have been theoretically investigated using the DFT (B3LYP/6-311+G*) level of theory. The geometries for reactants, intermediates, transition states and products were completely optimized. All the transition states were verified by the vibrational analysis and the intrinsic reaction coordinate calculations. The involving potential energy curve-crossing dramatically affects reaction mechanism, reaction rate has been discussed, and the crossing points (CPs) have been localized by the approach suggested by Yoshizawa et al. The present results show that the reaction mechanism are insertion–elimination mechanism both along the C–S and C–O bond activation branches, but the C–S bond activation is much more favorable in energy than the C–O bond activation. All theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction.     

LiMg0.5Mn1.5O4的合成及对Li+的离子交换选择性

锂及其化合物在航空航天、化工、医药、空调、高能电池和热核反应等方面都有广泛应用，对锂及其化合物的需求与日俱增。我国液体锂资源非常丰富，开发利用其中的锂资源具有重要意义。从盐湖水、地下卤水、盐田母液、油气田水等咸水资源中提取锂的方法有碳酸盐沉淀法、离子交换法、萃取法等。离子     

In situ generated pyroglutamate bridged polyoxotitaniums with strong circular dichroism signal

In this text, we use inexpensive and natural amino acid, successfully obtained the asymmetric crystallization of three PTCs, [Tis(O~iPr)_(14)(μ_2-O)(μ_3-O)_2(D/L-pGlu)_2](D-PTC-53; L-PTC-53; H2 pGlu=pyroglutamic acid) and [Ti_6(O~iPr)_(14)(μ_2-O)(μ_3-O)_2(D-pGlu)_2][Ti_6(O~iPr)_(14)((μ_2-O)(μ_3-O)_2(L-pGlu)_2](D,L-PTC-53). Interestingly, in situ lactamide reaction starting from glutamic acid to pyroglutamic acid was observed. In addition,the chirality features of these PTCs have been thoroughly discussed.The two enantiomers crys tallize in chiral P21 space group.The optically pure pGlu ligands transform its chirality to the inorganic titanium oxo clusters. As a result, the stack of these inorganic clusters generates homochiral helical chains along the characteristic axial direction.Apart from the microscopic structural analysis, the macroscopic solid-state samples exhibit unusual strong circular dichroism(CD) signals,further verified the homochiral feature of the enantiomers.     

Electric Potential (psi(delta) and psi(d)) at Outer Helmholtz Plane and Midplane on the Clay Colloid Surface with Overlapping Flat Double Layers

An anion negative adsorption equation in the condensed colloidal suspension with overlapping flat double layers was derived according to Gouy-Chapman theory. The electric potential at the outer Helmholtz plane (OHP), psi(delta), and the electric potential at the midplane, psi(d), were numerically solved by computer using the anion negative adsorption equation on the basis of experiments. The results showed that psi(delta) and psi(d) increase with the decrease of the distance between two clay plates, lambda, at first in the given electrolyte concentration. When lambda is smaller than 50-70 ?, psi(d) remains almost unchanged while psi(delta) declines remarkably with the further decrease of lambda. The change of psi(d)/psi(delta) with lambda can explain and manifest overlapping degree of flat double layers more appropriately than psi(d) in previous works. Due to compression of the flat double layer on the clay colloid surface at increasing electrolyte concentration, the magnitude of the electrical potentials at OHP and midplane is considerably reduced at a given lambda. Copyright 2000 Academic Press.     

“Self-repairing” nanoshell for cell protection

Self-repair is nature''s way of protecting living organisms. However, most single cells are inherently less capable of self-repairing, which greatly limits their wide applications. Here, we present a self-assembly approach to create a nanoshell around the cell surface using nanoporous biohybrid aggregates. The biohybrid shells present self-repairing behaviour, resulting in high activity and extended viability of the encapsulated cells (eukaryotic and prokaryotic cells) in harsh micro-environments, such as under UV radiation, natural toxin invasion, high-light radiation and abrupt pH-value changes. Furthermore, an interaction mechanism is proposed and studied, which is successful to guide design and synthesis of self-repairing biohybrid shells using different bioactive molecules.     

Copper-Catalyzed Cyanopropylation of Activated Alkenes

A practical copper-catalyzed alkylarylation of activated alkenes with azobisisobutyronitrile (AIBN) and beyond has been developed, in which incorporation of 3^o nitrile moiety into an oxindole scaffold proceeded smoothly through cascade radical addition/C(sp²)-H cyclization. The use of readily available AIBN as radical source and inexpensive CuI as catalyst, as well as broad substrate scope and the simplicity of operation and handling, make this protocol a highly attractive approach to oxindoles bearing 3^o nitrile moiety.     

Multicomponent Reaction for Synthesis of 2-(Indol-3-yl)pyridine Derivatives Under Microwave Irradiation

A short, practical, and efficient preparation of 2-(indol-3-yl)pyridine derivatives via a one-pot procedure of 3-cyanoacetylindole, chalcones, and ammonium acetate under microwave irradiation was described. All these compounds were obtained in good yield, and their structures were confirmed by ¹H NMR, infrared, and elementary analysis.