手性四薄荷基亚甲基双膦酸酯的制备与性质表征

膦酸及其酯的衍生物是有机磷化合物中重要的一部分,已被广泛应用于医药、农药、表面活性剂、金属防腐剂、高分子材料、工业软水剂等化工领域.其所含有的P—C—P键和烷氧基有许多可能的结构变化,是个很好的合成子.用亚甲基双膦酰二氯和薄荷醇反应,合成了手性四薄荷基亚甲基双膦酸酯(L2),并对其进行了IR、EA、1HNMR、31P NMR和CD等性质表征.用该双膦酸酯合成了三种新的配合物,并进行了红外表征.     

非线性微分系统稳定性定理的推广

利用非线性微分系统的变分系统,讨论了非线性微分系统解的一致稳定性和等度渐近稳定性,改进了文献[1-3]中相应的结果．     

数字旅游建设体系结构设计

数字旅游系统的总体框架和体系结构,是系统研究工作的核心和建设的依据.数字旅游的建设内容包括旅游信息基础设施的建设与旅游应用信息系统的建设;数字旅游的体系结构主要包括系统的逻辑设计、数据库设计以及功能设计.逻辑设计包括系统的硬件、软件和网络配置等组成部分.数据库是数字旅游系统的核心组成部分,是数字旅游应用系统运行的基础,数据库的合理设计有助于应用系统的高性能实现.数字旅游系统功能的设计是具有针对性的,主要包括数据管理、显示、查询、分析与评价功能、旅游信息网络发布功能、远程数据上报功能和三维景观系统功能等基本功能.     

分子电子学

作为纳米电子学的一个重要分支,分子电子学在近年来得到了巨大的发展,并成为国际上研究的热点。本文介绍了各种分子器件的制作技术及基本工作原理,回顾了近年来分子电子学的最新进展,展望了分子电子学的未来发展。     

LSMW在SAP系统中的应用

LSMW（遗产系统迁移工作台）是SAP提供对静态数据、动态数据、业务数据进行批量操作的工作台。介绍了在SAP系统中应用LSMW的工作流程及方法,包括数据准备、数据导入以及LSMW在中国石油销售ERP项目的实际应用。     

特厚煤层回采巷道顶板变形特征及控制技术

为了解决特厚煤层回采巷道顶板变形严重、支护困难等问题,通过现场观测和理论分析得出特厚煤层回采巷道变形因素及其特征,并利用FLAC3D数值模拟软件分析了在原支护和高强恒阻让压锚网索联合支护2种护巷方式下巷道围岩变形情况.研究结果表明:含软弱夹层的特厚煤层回采巷道自稳时间短,变形速度快,顶板破碎严重,塑性区破坏范围较大,巷...     

A new species of the genus Saussurella Bolivar 1887 from China,with a key to the species of the genus (Orthoptera: Tetrigidae)

Taxonomy of a tetrigid genus Saussurella Bolivar is reviewed. One new species, Saussurella brachycornis sp. nov. is described from China and an updated identification key to all known species of the genus is given, as well as brief comments on phylogenetic relationships and distributions of the genus.     

Prediction of Cancer-Associated piRNA–mRNA and piRNA–lncRNA Interactions by Integrated Analysis of Expression and Sequence Data

piwi-interactingRNAs(piRNAs) are valuable biomarkers, but functional studies are still very limited.Recent research shows that piRNA-mediated cleavage acts on Transposable Elements(TEs), messengerRNAs(mRNAs), and long non-codingRNAs(lncRNAs). This study aimed to predict cancer-associated piRNA-mRNA and piRNA-lncRNA interactions as well as piRNA regulatory functions. Four cancer types(BRCA, HNSC, KIRC,and LUAD) were investigated. Interactions were identified by integrated analysis of the expression and sequence data. For the expression analysis, only piRNA–mRNA and piRNA–lncRNA pairs with expression profiles that were significantly inversely correlated were retained to reduce false-positive rates during the prediction. For the sequence analysis, miRanda was used for the target prediction. We identified 198 piRNA–mRNA and 10 piRNA–lncRNA pairs. Unlike mRNA and lncRNA expressions, the piRNA expression was relatively consistent across the cancer types. Furthermore, the identified piRNAs were consistent with previously published cancer biomarkers, such as piRNA-36741, piR-21032, and piRNA-57125. More importantly, predicted piRNA functions were determined by constructing an interaction network, and piRNA targets were placed in gene ontology categories related to the cancer hallmarks "activating invasion and metastasis" and "sustained angiogenesis".     

An Inverse Power Generation Mechanism Based Fruit Fly Algorithm for Function Optimization

As a novel population-based optimization algorithm, fruit fly optimization(FFO) algorithm is inspired by the foraging behavior of fruit flies and possesses the advantages of simple search operations and easy implementation. Just like most population-based evolutionary algorithms, the basic FFO also suffers from being trapped in local optima for function optimization due to premature convergence.In this paper, an improved FFO, named IPGS-FFO, is proposed in which two novel strategies are incorporated into the conventional FFO. Specifically, a smell sensitivity parameter together with an inverse power generation mechanism(IPGS) is introduced to enhance local exploitation. Moreover,a dynamic shrinking search radius strategy is incorporated so as to enhance the global exploration over search space by adaptively adjusting the searching area in the problem domain. The statistical performance of FFO, the proposed IPGS-FFO, three state-of-the-art FFO variants, and six metaheuristics are tested on twenty-six well-known unimodal and multimodal benchmark functions with dimension 30, respectively. Experimental results and comparisons show that the proposed IPGS-FFO achieves better performance than three FFO variants and competitive performance against six other meta-heuristics in terms of the solution accuracy and convergence rate.