对教材中摩尔气体常数测定实验原理误解的更正

摩尔气体常数的测定是高等院校无机化学课程中的一个重要实验。然而,现行实验教材对该实验的实验原理分析中却出现了两处误解,即没有正确理解实验中有关理想气体状态方程式和道尔顿分压定律的应用。本文对这两处误解进行了分析和解释。     

Behavior of Endothelial Cells Regulated by a Dynamically Changed Microenvironment of Biodegradable PLLA‐PC

The influence of PLLA‐PC membranes on the behavior of vascular ECs is studied. It was found that the membranes were not cytotoxic. The cell adhesion and spread on PLLA‐PC 30/1 were initially depressed. After 1 d, however, cells attached and spread on the copolymer, and proliferated beyond 2 d. To elucidate the mechanism of this behavior, the surface morphology and the degradation products of the PLLA/PC 30/1 membrane during the culture period were tested, and Fg adsorption to the membranes was examined. It is concluded that the behavior of ECs can be regulated by a dynamically changed microenvironment of the PLLA‐PC membrane. PLLA‐PC copolymers might therefore serve as a novel material for tissue engineering.

     

路面面层用建筑垃圾再生粗骨料混凝土基本力学性能

通过废混凝土骨料和废砖骨料按比例混合模拟建筑垃圾的组成,制成建筑垃圾再生粗骨料混凝土。试验研究了建筑垃圾再生粗骨料混凝土路用的基本力学性能,试验结果显示:建筑垃圾再生粗骨料混凝土的抗压强度和抗折强度均随着水灰比增大而减少;当再生粗骨料中掺25%砖骨料时,建筑垃圾再生粗骨料混凝土基本力学性能满足新建水泥路面面层材料的要求;当掺量达50%时,此时砖骨料对再生混凝土路用基本力学性能影响较大。 更多还原     

Lamb waves in two-dimensional phononic crystal plate with anisotropic inclusions

An analysis is given to the band structure of the two-dimensional phononic crystal plate constituted of a square array of elastic anisotropic, circular Pb cylinders embedded in elastic isotropic epoxy. The numerical results show that the band gap can be tuned by rotating the anisotropic material orientation. It is found that the influence of anisotropy on band gap of Lamb wave is clearly different from that on the band gap of bulk waves. The thickness of the system under study is a sensitive parameter to affect the influence of anisotropic materials on the normalized gap width.     

Traffic dynamics based on a traffic awareness routing strategy on scale-free networks

By incorporating local traffic information into the shortest path routing strategy, we numerically investigate the effectiveness of the traffic awareness routing strategy for scale-free networks with different clustering. In order to characterize the efficiency of the packet-delivery process, we introduce an order parameter and an average transmission time that allow us to measure the network capacity by the critical value of phase transition from free flow to congestion. Compared with the shortest path routing protocol, the network capacity is greatly enhanced by the traffic awareness routing strategy. We also find that there exists an optimum value for the tunable parameter in the congestion awareness strategy. Moreover, simulation results show that the more clustered the network, the less efficient the packet-delivery process.     

含氮芥和蒽环的新型α,β-不饱和酮的合成、表征与抗肿瘤活性

为获得含氮芥和蒽环的α,β-不饱和酮衍生物及其体外抗肿瘤效果，结合Vilsmeier-Haack反应和羟醛缩合反应合成了两种新型含氮芥和蒽环的α,β-不饱和酮(1a和1b),其结构经¹H NMR、¹³C NMR、 MS(ESI)和紫外和荧光光谱表征。采用MTT法检测了1a和1b对肺癌细胞A549、肾癌细胞786-O、宫颈癌细胞Hela和乳腺癌细胞MDA-MB-231增殖的抑制活性；采用细胞划痕实验检测了1a对Hela细胞转移的影响；采用流式细胞仪(PI染色)检测了1a对Hela细胞周期的影响。结果表明：1a和1b对4种肿瘤细胞均有良好的抗增殖活性，其中1a的活性略高于1b;1a能有效抑制Hela细胞转移，并使Hela细胞周期阻滞在S期。