移动数据库及其关键技术

移动通信技术和数据库技术的发展,以及人们对移动数据处理的需求,推动了移动数据库技术的发展.本文阐述了移动数据库的相关概念,分析了几种移动数据库系统模型及其特点,并针对实现移动数据库系统的关键技术进行了初步的探讨,阐述了自己的想法.     

New Binuclear Complexes with Mixed Ligands and μ<Subscript>2</Subscript>-Phenol Oxygen Bridges: Synthesis Crystal Structures and Magnetism

Two new complexes, [M₂(L)₂(bpy)₂](ClO₄)₂ [L = methyl salicylate, bpy = 2,2′-bipyridine, M = Cu (1) and Zn (2)] have been synthesized and structurally characterized by X-ray structure analyses. The centrosymmetric dimeric structure consists of a binuclear unit, in which M (M = Cu or Zn) atoms are bridged by two phenol oxygen atoms as a μ ₂-bridged. The neighboring binuclear units interact with each other by two kinds of weak contacts: one kind is π–π stacking by π–σ attraction with an edge-to-face C–H···π interaction, and the second type is a H-bonding interaction, which extends the binuclear unit into a 3D network. Magnetic measurements confirm that 1 presents a very strong intradinuclear ferromagnetic coupling between the copper(II) ions.     

应用于大功率MMIC开关的AlGaN背势垒GaN HEMT

报道了应用于大功率开关的AlGaN背势垒0.25μm GaN HEMT。通过引入AlGaN背势垒,MOCVD淀积在3英寸SiC衬底上的AlGaN/GaN异质结材料缓冲层的击穿电压获得了大幅度的提升,相比于普通GaN缓冲层和掺Fe GaN缓冲层击穿电压提升幅度分别为4倍和2倍。采用具有AlGaN背势垒AlGaN/GaN 外延材料研制的GaN HEMT开关管在源漏间距为2μm、2.5μm、3μm、3.5μm和4μm时,估算得到的关态功率承受能力分别为25.0W、46.2W、64.0W、79.2W和88.4W。基于源漏间距为2.5μm的GaN HEMT开关管设计了DC-12GHz的单刀双掷MMIC开关。该开关采用了反射式串-并-并结构,整个带内插入损耗最大1.0dB、隔离度最小30dB,10GHz下连续波测试得到其功率承受能力达44.1dBm。     

Integrative computational approach to evaluate risk genes for postmenopausal osteoporosis

In recent years, numerous studies reported over a hundred of genes playing roles in the etiology of postmenopausal osteoporosis (PO). However, many of these candidate genes were lack of replication and results were not always consistent. Here, the authors proposed a computational workflow to curate and evaluate PO related genes. They integrate large‐scale literature knowledge data and gene expression data (PO case/control: 10/10) for the marker evaluation. Pathway enrichment, sub‐network enrichment, and gene–gene interaction analysis were conducted to study the pathogenic profile of the candidate genes, with four metrics proposed and validated for each gene. By using the authors'' approach, a scalable PO genetic database was developed; including PO related genes, diseases, pathways, and the supporting references. The PO case/control classification supported the effectiveness of the four proposed metrics, which successfully identified eight well‐studied top PO genes (e.g. TGFB1, IL6, IL1B, TNF, ESR2, IGF1, HIF1A, and COL1A1) and highlighted one recently reported PO genes (e.g. IFNG). The computational biology approach and the PO database developed in this study provide a valuable resource which may facilitate understanding the genetic profile of PO.Inspec keywords: biology computing, genetics, diseases, boneOther keywords: risk genes, postmenopausal osteoporosis, integrative computational approach, gene expression data, gene‐gene interaction analysis, IL1B, TNF, ESR2, HIF1A, COL1A1, PO genes     

活性污泥法的工艺参数控制(下)

2 污泥沉降比(SV30) 2.1 理论定义及实际应用上的理解 SV30是指曝气池混合液在量筒静止沉降30 min后污泥所占的百分体积.     

Magnetic and Electric Control of Circularly Polarized Emission through Tuning Chirality‐Generated Orbital Angular Momentum in Organic Helical Polymeric Nanofibers

Circularly polarized light emission promotes the development of smart photonic materials for advanced applications in chiral sensing and information storage. The orbital angular momentum is a unique property for organic chiral helical materials. In this work, a type of organic chiral polymeric nanowires is designed with strong chirality induced orbital angular momentum. Under the stimulus of an external magnetic field of 600 mT, circularly polarized emission from the chiral polymeric nanowire becomes more pronounced, where the g factor increases from 0.21 to 0.3. The observed phenomena mainly originate from the chirality‐dependent orbital angular momentum. Moreover, the orbital angular momentum in helical chiral nanowire structures can be suppressed by inhibiting electron transport in a helical way to diminish circularly polarized light emission at room temperature.     

用自滤波及注入锁定提高铜蒸气激光在BBO晶体中的倍频效率

本文采用自滤波非稳腔振荡和注入锁定放大的铜蒸气激光系统,获得了发散角为0.22mrad,偏振度为93％,510.6nm线输出功率为9.2W的激光束。将这一光束聚焦到长9mm的BBO晶体中,获得了1.2W的倍频光,其转换效率为13％,当移去滤波小孔后,所产生的倍频效率下降到8％。     

两种典型结构强流自箍缩二极管技术研究

主要介绍了箍缩聚焦二极管和自箍缩离子束二极管的研究进展。重点介绍了近几年发展的阳极杆箍缩聚焦二极管的理论模拟和实验结果,在“闪光二号”加速器和2MV脉冲功率驱动源上进行了阳极杆箍缩二极管实验,二极管输出电压1．8—2．1MV,电流40—60kA,脉宽（FWHM）50～60n8,1m处的脉冲X剂量约20～30mGy,焦斑直径约Imm,X射线最高能量1．8MeV。在“闪光二号”加速器上开展了高功率离子束的产生和应用研究,给出了自箍缩反射离子束二极管的结构和工作原理,实验获得的离子束峰值电流～160kA,离子的峰值能量-500keV,开展了利用高功率质子束轰击19F靶产生6～7MeV准单能脉冲γ射线,模拟x射线热一力学效应等应用基础研究。     

烟囱结构竖向地震作用研究进展

目前在工程结构抗震领域中,关于结构水平地震作用的研究已经形成了比较完善的理论体系和抗震设计方法;然而通过理论研究和对大量震害现象的分析表明,竖向地震作用对结构的作用不容忽视。国内外学者对烟囱结构的竖向地震作用展开了深入的研究,取得了丰硕的成果。介绍了目前国内关于烟囱结构竖向地震作用的研究现状,内容包括烟囱结构竖向地震作用的震害分析、烟囱竖向地震作用计算理论的研究、烟囱竖向地震作用的试验研究。最后讨论了存在的问题,提出了今后值得研究的若干问题。     

试论建筑工程招投标中工程量清单的运用

自改革开放和加入WTO以来,我国工程造价管理体系的改革不断深化,取得了巨大的成就,而国家标准《建设工程工程量清单计价规范》(GB50500-2003)的颁布更是意味着我国建设工程的计价模式产生了质的变化,定额计价模式把工程量清单的变革和工程施工企业的竞争以及造价管理推向一个更加科学和规范的层面上.