植物内皮层凯氏带及其在抗盐胁迫中的作用

内皮层凯氏带是植物根中水分和离子径向运输的屏障.由于内皮层凯氏带的精细结构及化学性质等方面的研究难度较大,因此多年来进展缓慢.随着显微技术和鉴定方法的不断改进,对凯氏带的结构和功能的研究得以深入,但对其发育、化学成分及与抗盐胁迫的关系方面的报道还不多见.本文就凯氏带的结构发育、化学组成以及其在抗盐胁迫中的作用进行了综述...     

应对逆境中的管理挑战

之前的经济和平已经成了历史,现在,我们都身处你死我活的市场之战中.饱受着恐惧、不确定和相互怀疑的困扰.与身处所有战场的情形一样,这种前所未有的争斗,要求有与和平时期完全不一样的领导类型的人.领导者必须时刻准备,在信息非常不完整的情况下,做出战略、组织结构、财务以及行动方面的调整和决策,其中的一些变化,可能非常剧烈.     

应对逆境中的管理挑战

要确定事情发展的方向。不是一件容易的事。就算在市场顺风顺水的时期，未来也总是笼罩在迷雾中，但对未来不屈不挠的追求，并为此做好最糟糕的打算和充分的准备，就能收到应有的回报。     

用强大执行力应对逆境

在经济不确定的时代,不断收紧的预算、崩溃的市场、越来越低的士气、供应商正被迷雾笼罩着,但是对未来不屈不挠的追求,加上应对最糟糕时期的务实方法,能使你找到希望之光     

全球经济逆境中的生存之道

金融危机所带来的是短期信贷不足，它将影响公司支付日常短期资金周转的能力。企业停止资金支出，差旅、培训等不必要费用被削减，IT预算也不能幸免。Garmer预测，2009年大部分的IT预算都不会超过2．5％，个别公司甚至还会削减2．50%-20%的预算支出。     

中国导航产业在逆境中酝酿突破

08年政府政策和管理的重心是网上地图的管理和相关法规的出台。可以期待政府在09年将重心转移到打击盗版，以及建立有关在线服务、3D和街景影像的法律法规方面来，这些方面对导航产业的持续健康发展将起到至关重要的影响。     

扫描电子显微镜在植物中的应用研究进展

扫描电子显微镜(SEM)作为一种行之有效的科研分析工具,可对多种植物材料的表面形貌进行观察研究,具有较广的应用范围.本文论述了扫描电子显微镜样品的制备以及在植物花器官、种子表皮、种子形态、叶片表皮、内含物、病原体以及在植物细胞水平的研究进展,并对今后扫描电子显微镜的应用前景进行了展望,以期为利用SEM从事植物研究的科研...     

超弱发光在植物生理学中的应用

超弱发光在植物生理学中的应用陈汝民孟耀勇，谭石慈罗金梅，张有（华南师范大学生物系５１０６３１）（激光生命科学实验室）（华南量子电子学研究所）关键词超弱发光，植物生理学ＡｐｐｌｉｃａｔｉｏｎｏｆＵｌｔｒａｗｅａｋＰｈｏｔｏＥｍｉｓｓｉｏｎｉｎＰｌａｎｔ...     

植物细胞膜受体胞吞及其功能的研究进展

细胞膜受体蛋白在细胞应对外部环境变化以及感知相邻细胞信号过程中发挥重要作用.当细胞膜受体蛋白受到配体刺激之后,依赖不同的胞吞机制,形成了两种主要的胞吞途径:网格蛋白介导的胞吞和不依赖网格蛋白介导的胞吞.通过不同胞吞途径进入细胞的细胞膜受体蛋白,会在不同内涵体间转运,从而引发不同的内涵体信号,然后一部分膜受体蛋白重新循环到细胞膜,另一部分则转运到溶酶体或液泡进行降解,最终影响植物的生长发育和免疫等过程.由于膜受体介导的胞吞作用和内涵体信号受到越来越多的关注,因此本文对细胞膜受体介导的胞吞机制及其在植物生长发育和抗病中的作用进行了综述,以期为今后系统开展其功能研究提供理论依据.     

激光对油松在干旱胁迫下萌发及酶活性的影响

在干旱胁迫条件下,对激光辐照的油松种子进行了萌发试验,并对其幼苗进行了超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性和丙二醛(MDA)含量的测定。结果表明:激光辐照油松种子在干旱胁迫条件下的发芽率、根长、活力指数、生物量等显著提高,萌发期油松幼苗保护酶系统的超氧化物歧化酶和过氧化物酶活性明显提高,膜脂的过氧化物丙二醛含量下降,减少了膜脂过氧化作用对膜的伤害。从而说明,激光辐照油松种子在干旱胁迫条件下萌发及幼苗生长的抗旱性效应明显增强。     

植物生长调节剂对大豆子粒超微结构的影响

本研究以东农46为试验材料,在大豆生长发育期对其叶面喷施4种植物生长调节剂：三碘苯甲酸（TIBA）、硝酸稀土（RE）、亚硫酸氢钠（SBS）、2-N,N-二乙氨基乙基乙酸酯（DTA-6）.通过对大豆贮藏细胞亚显微结构观察发现,在鼓粒期TIBA对蛋白质体聚集起到了一定的作用,SBS使蛋白质体形状不规则,贮藏细胞中淀粉粒较多.RE和DTA-6对增加蛋白质体和脂体的数量效果显著.在生理成熟期,TIBA对蛋白质体聚集作用效果不明显,而使脂体数量增加,排列更紧密.RE处理样贮藏细胞蛋白质体和脂体仍较多.SBS处理样贮藏细胞淀粉粒蛋白质体较多.DTA-6使蛋白质体增多、形状大小不均一,蛋白质体的平均直径大于对照.在成熟期,贮藏细胞的物质丰富,蛋白质体较大.RE、SBS和DTA-6处理样的贮藏细胞中蛋白质体多,其中RE使蛋白质体排列更紧密.DTA-6使蛋白质个体增大,但贮藏细胞中仍有一些淀粉粒没有转化,说明DTA-6减缓了淀粉粒的降解及转化速度.SBS处理样的贮藏细胞脂体排列疏松,RE和TIBA处理样的贮藏细胞中脂体排列紧密,而且饱满.实验表明,植物生长调节剂对大豆子粒贮藏细胞的生长发育有显著影响.在大豆生长的某些特定阶段（从苗期到盛花期、鼓粒始期）,喷施本实验选定的4种植物生长调节剂,均可实现增加产量、提高品质的目的.其中RE、DTA-6增产可达17.00％、21.83％,增产效果十分显著.喷施TIBA的大豆植株矮化、壮杆效果明显,株高降低了28％ ～ 30％,抗倒伏能力显著提高.     

虚拟植物研究进展

介绍了虚拟植物的研究意义,阐述了各种典型的虚拟植物建模方法,对不同的建模方法进行比较分析,总结了不同的建模方法的优点和不足之处,进而提出了虚拟植物研究中存在的问题.     

应力水平下的激光冲击小孔构件疲劳扩展研究

激光冲击强化可以降低小孔构件裂纹扩展速率,提高疲劳寿命。疲劳扩展是疲劳寿命的主要组成部分,不同的应力水平会影响疲劳扩展,其对未强化试样和强化试样的影响是不同的。为此通过激光冲击强化TC4-DT钛合金双联小孔试样,然后进行疲劳试验,研究应力水平下的激光冲击小孔构件疲劳扩展。研究结果表明：应力水平提高会导致疲劳条带宽度增大,同时强化端同比增大尺寸大于未强化端,未强化端(I0)和强化端疲劳条带宽度(I1)差值(I0-I1)与未冲击端疲劳条带宽度(I0)的比值也有降低的趋势。因此,增大应力水平会增大疲劳条带宽度,应力水平的变化对激光冲击强化后试样的疲劳扩展影响更大,应力水平增大降低激光冲击强化疲劳寿命增益;在激光冲击强化参数一定时,应该规定适用的应力水平范围。     

电子产品研制阶段可靠性增长试验研究

结合工程实际经验,深入讨论了可靠性增长过程及实现途径,在保持试验条件和改进过程不变的条件下,实施了对具体型号电子产品的可靠性增长试验,达到了预期的可靠性增长目标,并且利用可靠性增长试验的数学模型(AMSAA模型)来评估产品的可靠性增长,对开展可靠性增长与可靠性增长试验工作具有重要的实际意义.     

Achieving millennium development goals: Role of ICTS innovations in India

The paper outlines the problem faced by India, in dealing with its rural poor, who live in 600,000 villages with poor infrastructure and continue to do so, even after 60 years of independence and constitute about 72.2% of 1027 million. The paper also deals with means and measures to increase their income level. To achieve this, the government must redefine its policies and strategies, deploy information and communication technologies (ICTs) innovations with application and active participation from development organizations. It presents an overview of ICTs and their role in development, particularly in the context of millennium development goals (MDGs). Details select ICTs innovations of India in achieving MDGs. Further, it lists out India’s position in relation to MDGs by highlighting India’s target, current status and steps taken to achieve them. Concludes that with well thought out planning, comprehensive development strategies devised in the national policy and matching implementation process, it is hoped that India will be able to meet the challenges and achieve all the MDGs targets much earlier than the targeted dates. India’s progress in achieving the MDGs will impact not only on its own people but also on the development of South Asia and the world.     

Surface and interface stress effects on the growth of thin films

Surface and interface stresses represent the work per unit area to stretch the surface of a solid. These types of stresses are discussed, emphasizing their relevance to thin film growth. In particular, the influence of these parameters on the critical thickness for epitaxy and for intrinsic thin film stress generation are considered.     

The effect of grain orientation on the relaxation of thermomechanical stress and hillock growth in AI-1%Si conductor layers on silicon substrates

Hillocks are formed sporadically in Al-l%Si sputter layers on SiO₂/Si substrates during heat treatments in the range from 200 to 500°C. The driving force is the relaxation of thermomechanical stress in the grains induced by the thermal expansion mismatch between the metallization layer and the substrate. The orientations of individual grains and hillocks are measured on-line with a medium voltage transmission electron microscope by the Kikuchi pattern method. Thermomechanical stress in the grains is calculated with a biaxial strain model, considering the glide systems of dislocations for the individual grain orientations. In general, hillocks deviate from the ordinary 〈111〉 fiber texture of aluminum sputter layers. The spatial distribution of grain orientations is illustrated by orientation images using Miller indices or Rodrigues vectors.     

The microstructure,mechanical stress,texture, and electromigration behavior of Al-Pd alloys

As the minimum feature size of interconnect lines decreases below 0.5 urn, the need to control the line microstructure becomes increasingly important. The alloy content, deposition process, fabrication method, and thermal history all determine the microstructure of an interconnect, which, in turn, affects its performance and reliability. The motivation for this work was to characterize the microstructure of various sputtered Al-Pd alloys (Al-0.3wt.%Pd, Al-2Cu-0.3Pd, and Al-0.3Nb-0.3Pd) vs sputtered Al-Cu control samples (Al-0.5Cu and Al-2Cu) and to assess the role of grain size, mechanical stress, and crystallographic texture on the electromigration behavior of submicrometer wide lines. The grain size, mechanical stress, and texture of blanket films were measured as a function of annealing. The as-deposited film stress was tensile and followed a similar stress history on heating for all of the films; on cooling, however, significant differences were observed between the Al-Pd and Al-Cu films in the shape of their stress-temperature-curves. A strong (111) crystallographic texture was typically found for Al-Cu films deposited on SiO₂. A stronger (111) texture resulted when Al-Cu was deposited on 25 nm titanium. Al-0.3Pd films, however, exhibited either a weak (111) or (220) texture when deposited on SiO₂, which reverted to a strong (111) texture when deposited on 25 nm titanium. The electromigration lifetimes of passivated, ≈0.7 μm wide lines at 250°C and 2.5 × 10⁶ A/cm² for both single and multi-level samples (separated with W studs) are reported. The electromigration behavior of Al-0.3Pd was found to be less dependent on film microstructure than on the annealing atmosphere used, i.e. forming gas (90% N₂-10%H₂) annealed Al-0.3Pd films were superior to all of the alloys investigated, while annealing in only N₂ resulted in poor lifetimes.     

The effect of strain on abnormal grain growth in Cu thin films

To understand a grain growth mechanism in Cu thin films that were deposited on rigid substrates by sputter deposition and subsequently annealed at various temperatures, microstructures of the Cu films with or without the rigid substrates were analyzed by x-ray diffraction (XRD), transmission electron microscopy (TEM), and electrical resistivity measurements. Significant grain growth (with bimodal grain size distribution) was observed during room-temperature storage in the Cu films deposited on the Si₃N₄ and rock salt substrates. However, in the free-standing Cu films, no grain growth was observed during room temperature storage. The present result suggested that the grain growth rates in the Cu thin films were strongly influenced by the existence of the rigid substrates, indicating stress (or strain) introduced in the films was a primary factor to induce the grain growth in the Cu films.     

关于计算机软件开发与发展研究

由于现阶段特别广泛的应用计算机,这不但改变着人们的生活、学习以及工作方式,甚至还能推动社会发展.计算机的组成部分为软件与硬件,那么计算机的硬件功能则是输入与存储程序、数据,还有的就是执行程序加工数据为能够利用的形式,计算机软件就如同人们的思想,电脑缺乏软件就根本无从谈及做什么事情.本文通过探讨计算机软件开发与发展,以期可以梳理计算机软件开发与发展的基本情况.