186 resultados para 206-1256D


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简单介绍了影响光催化氧化有机物反应速度的五个因素,通过分析找出影响光催化氧化有机物反应速度的主要因素,必须同时考虑反应内E_((r))和S_((r))相互综合因素对反应器自由基产生率的影响;通过实验方法找出对应不同功率光源的光催化载体最优半径r_(opt)具体数值,是提高固定膜光催化氧化净水器性能的关键,如果把固定光催化膜载体布置在半径r_(opt)的圆周上,就能充分利用光源的光能,在反应器有限的空间内使得适当强度的紫外光照射到有效光催化剂的面积适当,这时光催化反应器光能利用率最高。

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科学数据是重要的科技资源,科学数据的共享管理日益成为学术界和政府关注的前沿领域。地球科学门类众多,研究对象复杂且往往时空尺度大,在此过程中产生了大量数据结构形式各异的数据,诸如图型数据、表格数据、文本数据、影像数据等等。在数据库系统环境下如何对这些异构的数据进行存储、发布、显示是科学数据管理必须首先面对的问题。在分析研究地球科学数据特征的基础上,结合黄土高原数据中心的建设实践,以科学数据共享管理为目标,对地球科学研究数据的分类和组织进行了研究。阐述了地球科学研究数据的异构性、密集性、复合性等基本属性和特征,提出了关系类型、空间类型、文件类型等3种基本类型的数据集分类和组织方式,并提出了整编数据集的基本原则和方法以及科学数据分级、保护、共享的方式。实践表明:该数据分类与组织技术方案符合地球科学研究数据的特点,并将科学数据管理与计算机网络技术、信息技术有机结合,具有思路与技术的先进性和广泛的应用场合。

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本文进行了大豆种子超氧岐化酶和大豆品质因素(脂肪酸)之间的相关性研究。在这一研究中,我们使用了三种方法:1、HPLC分离测定脂肪酸的组成。2、用聚丙烯酰胺凝胶电泳研究同功酶。3、建立了自旋捕捉方法分析超氧岐化酶的活性。我们对二十四种大豆进行了研究:虎林野生大豆、公主岭野生大豆、秣食豆、黑豆、金元1号、满仓金、小金黄、东农4号、大白眉、早丰1号、十胜长叶、阿姆索、九农9号、黑河3号、绥农4号、黑农26号、吉林3号、合丰23号、哈76-6296、辽宁3号、吉林20、铁丰18、长农4号和EVANS、结果表明大豆种子SOD的比活力和其油脂含量呈极显著负相关;和亚麻酸含量呈极显著正相关;和油酸含量呈极显著负相关;和棕榈酸含量呈显著正相关;和亚油酸含量基本无关;和不饱和脂肪酸和为负相关。其直线回归方程分别为:Yoil = 27.72270-193.04800X比活力 Y18:3 = 3.64289 + 86.69367X比活力 Y18:1 = 31.42366 - 206.61395X比活力 Y16:0 = 9.03986 + 73.46336X比活力 只考虑栽培大豆,它们均未达到5%的显著水平。同功酶的研究结果表明,同功酶可分三个谱带区:A、B和C区,A区为MN-SOO、B、C区均为Cu、Zn-SOD。其中:虎林野生大豆、公主岭野生大豆,秣食豆、黑豆均有两条Mn-SOD同功酶谱带,其余二十个品种栽培大豆均有一条。吉林3号、吉林20的B区只有一条Cu、Zn-SOD同功酶谱带,其余二十二种大豆均有三条。C区都为三条Cu、Zn-SOD同功酶谱带。A、B和C区的百分量和大豆含油量、脂肪酸进行相关分析。结果表明,只有栽培大豆的A区和亚麻含量为显著负相关,其它均没达到5%的显著水平。其直线回归方程为:YA = 43.3277 - 2.5481 X18:3对用HPLC分离脂肪酸的文献方法进行了改进,由文献的1小时改进到每个样品十八分钟。并对二十四种大豆的脂肪酸组成进行了分离测定,结果发现,野生大豆、半栽培大豆和黑豆的亚麻酸含量高于栽培大豆。对光照核黄素体系,DMPO捕捉O_2:的机理进行了探讨。通过SOD抑制O_2~-的DMPO捕捉加合物DMPO-OOH的生成,建立了用自旋捕捉方法分析SOD的活性,并对二十四种大豆种子SOD的活性进行了分析,结果发现,野生大豆,半栽培大豆和黑豆的SOD比活力偏高。

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The growth of high quality AlGaAs by CBE bas been limited by the high levels of carbon and oxygen contamination. The use of alane based precursors offers a significant reduction in such contamination. We report for the first time the CBE growth of AlxGa1-xAs from triethylgallium, dimethylethylamine-alane and arsine, and compare with. growth from triethylgallium, trimethylamine-alane and arsine. Some preliminary results of work on the CBE growth of GaAs on silicon will also be reported.

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Silicon-based high-speed electro-optical modulator is the key component of silicon photonics for future communiction and interconnection systems. In this paper, introduced are the optical mudulation mechanisms in silicon, reviewed are some recent progresses in high-speed silicon modulators, and analyzed are advantages and shortages of the silicon modulators of different types.

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CMOS折叠预放电路的失凋是限制CMOS折叠结构A/D转换器实现高分辨率应用的主要原因之一.文中提出差分对的动态匹配技术改善了折叠预放电路的失调,从而为研制CMOS工艺中的高分辨率折叠结构A/D转换器提供了一种可行方案,并给出了MATLAB和电路仿真的实验结果.

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用电子能谱分析方法对低能离子束外延(IBE)生长的β-FeSi_2进行了详细研究,并对其电子能谱进行了表征。实测出XPS价带谱与有关理论计算结果相符,用XPS价带谱来表征β-FeSi_2比光电子峰更为清晰、可取。同时,对样品纵向分析表明界面处存在有较厚的过渡层。根据分析结果对低能IBE生长机理进行了探讨。经研究认为:Fe,Si通过空位机制进行的增强互扩散,在高温下生长出与Si晶格相匹配的β-FeSi_2。

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The hole effective-mass Hamiltonian for the semiconductors of wurtzite structure is established, and the effective-mass parameters of GaN and AlxGa1-xN are given. Besides the asymmetry in the z and x, y directions, the linear term of the momentum operator in the Hamiltonian is essential in determining the valence band structure, which is different from that of the zinc-blende structure. The binding energies of acceptor states are calculated by solving strictly the effective-mass equations. The binding energies of donor and acceptor for wurtzite GaN are 20 and 131, 97 meV, respectively, which are inconsistent with the recent experimental results. It is proposed that there are two kinds of acceptors in wurtzite GaN. One kind is the general acceptor such as C, substituting N, which satisfies the effective-mass theory, and the other includes Mg, Zn, Cd etc., the binding energy of which deviates from that given by the effective-mass theory. Experimentally, wurtzite GaN was grown by the MBE method, and the PL spectra were measured. Three main peaks are assigned to the DA transitions from the two kinds of acceptor. Some of the transitions were identified as coming from the cubic phase of GaN, which appears randomly within the predominantly hexagonal material. The binding energy of acceptor in ALN is about 239, 158 meV, that in AlxGa1-xN alloys (x approximate to 0.2) is 147, 111 meV, close to that in GaN. (C) 2000 Published by Elsevier Science S.A. All rights reserved.