Gas-liquid phase coexistence and finite-size effects in a two-dimensional Lennard-Jones system

The gas-liquid phase coexistence in a two-dimensional Lennard-Jones system is investigated using Maxwell construction method together with molecular dynamics simulations.The results of phase coexistence in different truncations of the potential are compared with data obtained from the literature,and the corresponding critical properties calculated.The crossover from Ising-like to mean field behavior is observed and confirmed as the temperature approaches the critical point from below.Performing simulations on systems with different sizes,we find that a finite size effect is more significant than those shown in most of the previous results,and a lower critical temperature is obtained when the full extent of this finite size effect is considered.     

硅、锗中硼、磷杂质的振动特性

本文用六原子模型．分析丁硼、磷原子在硅、锗半导体中刃位错附近的三维振动特性．     

光催化H2O2氧化荧光法测定艾司唑仑

研究了艾司唑仑在光催化下Ｈ２Ｏ２氧化产物的荧光性质，提出一种测定艾司唑仑的新方法．标准曲线的范围为０．６０～５．６０μｇ·Ｍｌ（－１），方法的相对标准偏差和检测限分别为２．１％和０．３１μｇ·ｍＬ（－１）．可直接用于片剂中艾司唑仑含量的测定．     

昆明酒店式公寓开发现状与对策研究

酒店式公寓以其＂酒店式的服务,公寓式的选择＂这一特质逐渐成为大众的选择、商家的投资热点。昆明酒店式公寓开发面临较好的机遇与选择,科学制定其开发策略,能有效提升昆明的品牌形象,促进其跨越式发展。     

房地产信贷风险分析

房地产是一项周期长、数量大的高投入经营活动,而我国的房地产金融体系是以银行为主导.政府宏观调控的滞后效应和房地产市场的大幅度明显波动,商业银行巨额房地产开发贷款系统风险和个人贷款风险不断聚积,对于商业银行资产质量的影响日渐显现.     

偶数阶拟线性偏泛函微分方程系统有关边值问题的振动性

本文研究了一类偶数阶拟线性偏泛函微分方程系统在Robin,D irichlet边值条件下解的振动性,获得了系统所有解振动的若干充分判据,这些结果推广和包含了已知的一些结果.     

住房公积金制度的建立与作用

住房公积金制度作为与住房改革配套的制度,以它独特的作用、地位、性质、特点,越来越为广大人民群众所接受和认可,成为城镇职工、居民建房、购房的主要支撑点,显示出它的强大生命力.     

粘钢加固RC梁的锚固剪应力参数分析

在弹性理论的基础上,利用钢板固剪应力计算公式,对在集中荷载或均布荷载作用下采用粘钢加固的混凝土梁,风板锚固最大剪应力的有关影响因素。     

Polo inhibits progenitor self-renewal and regulates Numb asymmetry by phosphorylating Pon

Self-renewal and differentiation are cardinal features of stem cells. Asymmetric cell division provides one fundamental mechanism by which stem cell self-renewal and differentiation are balanced. A failure of this balance could lead to diseases such as cancer. During asymmetric division of stem cells, factors controlling their self-renewal and differentiation are unequally segregated between daughter cells. Numb is one such factor that is segregated to the differentiating daughter cell during the stem-cell-like neuroblast divisions in Drosophila melanogaster, where it inhibits self-renewal. The localization and function of Numb is cell-cycle-dependent. Here we show that Polo (ref. 13), a key cell cycle regulator, the mammalian counterparts of which have been implicated as oncogenes as well as tumour suppressors, acts as a tumour suppressor in the larval brain. Supernumerary neuroblasts are produced at the expense of neurons in polo mutants. Polo directly phosphorylates Partner of Numb (Pon, ref. 16), an adaptor protein for Numb, and this phosphorylation event is important for Pon to localize Numb. In polo mutants, the asymmetric localization of Pon, Numb and atypical protein kinase C are disrupted, whereas other polarity markers are largely unaffected. Overexpression of Numb suppresses neuroblast overproliferation caused by polo mutations, suggesting that Numb has a major role in mediating this effect of Polo. Our results reveal a biochemical link between the cell cycle and the asymmetric protein localization machinery, and indicate that Polo can inhibit progenitor self-renewal by regulating the localization and function of Numb.     

Intersections of two offset parametric surfaces based on topology analysis

Conventional methods for solving intersections between two offset parametric surfaces often include iteratively using computationally expensive SSI (surface/surface intersections) algorithm. In addition, these methods ignore the relations between the intersection curves of parametric surfaces with different offset distances. The algorithm presented in this paper, makes full use of the topological relations between different intersection loops and calculates intersection loops with the help of previously calculated intersection loops. It first pre-processes two parametric surfaces to obtain the characteristic points, called topology transition points (TTPs), which can help in the subsequent finding of the topologies of the intersection curves. Then these points are categorized into several distinct groups, and we can determine the calculation strategy for searching initial points by analyzing the properties of these TTPs on the surfaces. Hence, all intersection curves can be marched from initial points by the tracing algorithm. The proposed algorithm could calculate intersection curves robustly and effectively, and has been tested to be capable of overcoming the degenerate conditions such as loop and singularities leaking that occur frequently in conventional algorithms.