4A和13X分子筛去除水中重金属Cd2＋及其吸附性能研究

以4A和13X分子筛为吸附材料,考察废水pH值和Cd2＋初始浓度等对Cd2＋去除率的影响,并研究了分子筛对Cd2＋的吸附性能。结果表明,4A和13X分子筛投加量为0．16 g/L、废水pH值为5、Cd2＋浓度为20 mg/L时,Cd2＋去除率达到95％以上;分子筛对Cd2＋的去除机理以离子交换吸附为主,交换出来的Na＋与分子筛吸附的Cd2＋摩尔浓度比为2;在吸附热力学和动力学方面,4A和13X分子筛均符合Langmuir吸附等温模型和Lagergren二级速率方程,计算的饱和吸附容量 Q0分别为150．15、163．67 mg/g ,二级反应速率常数K2分别为2．45＆#215;10-3、3．96＆#215;10-4 g/（mg ＆#183; s）。该吸附反应是一种单分子层反应速度较快的化学吸附过程。     

流动与传热数值模型的发展现状

流动与传热的数值模型发展至今已有三十多年的历史 ,该文拟结合炉内流动模型的特点 ,从差分格式、迭代组织形式、网格生成等三方面对流动、传热数值方法的发展现状作一简单介绍。参 9     

人事档案管理CAD

在对基层组织人事档案管理现状分析的基础上，提出了人事档案管理计算机辅助系统的设计目的及任务，并介绍了系统的结构及主要功能。     

高水分玉米应用臭氧防霉综合治理试验研究

本文为臭氧防霉实验研究。25℃条件下,10～20ppm臭氧直接处理串珠镰刀菌、黄曲霉、黑曲霉、草酸青霉、圆弧青霉,每天处理8小时,明显抑制其生长发育,连续处理效果更佳。用臭氧保藏高水分玉米,接触臭氧玉米不霉变,但臭氧渗透差,必须辅以通风。20℃时向含水量23.42％玉米中通入10ppm臭氧,可向下渗透1米,1米处O_3为0.5ppm,交换次数约每5分钟一次,玉米保藏20天未发生霉变,加大O_3浓度,O_3可渗透至1.5米。2～10ppm臭氧25℃时处理水分21.05％的玉米,玉米过氧化值、脂肪酸值均无明显变化。较新鲜玉米香味略差,但仍较对照样品好。试验还证明受臭氧处理玉米发芽率略有降低。     

西三角经济圈传媒产业发展探析——基于马克思主义新闻理念

西部大开发战略实施十年,西部进入到一个新的发展转折时期.西三角经济圈的建立,意味着在该范围内经济建设将采取更加开放的政策,意味着市场之间的接轨,意味着知识经济将会以更快的速度发展.这给西三角经济圈传媒产业的发展带来了新机遇.领会马克思主义新闻理念的精髓,,抓住"西三角经济圈"发展带来的机遇,用科学的理论指导传媒产业的发展,可以取得良好的社会效益和经济效益.     

Role of ERAB/L-3-hydroxyacyl-coenzyme A dehydrogenase type II activity in Abeta-induced cytotoxicity

Endoplasmic reticulum-associated amyloid beta-peptide (Abeta)-binding protein (ERAB)/L-3-hydroxyacyl-CoA dehydrogenase type II (HADH II) is expressed at high levels in Alzheimer's disease (AD)-affected brain, binds Abeta, and contributes to Abeta-induced cytotoxicity. Purified recombinant ERAB/HADH II catalyzed the NADH-dependent reduction of S-acetoacetyl-CoA with a Km of approximately 68 microM and a Vmax of approximately 430 micromol/min/mg. The contribution of ERAB/HADH II enzymatic activity to Abeta-mediated cellular dysfunction was studied by site-directed mutagenesis in the catalytic domain (Y168G/K172G). Although COS cells cotransfected to overexpress wild-type ERAB/HADH II and variant beta-amyloid precursor protein (betaAPP(V717G)) showed DNA fragmentation, cotransfection with Y168G/K172G-altered ERAB and betaAPP(V717G) was without effect. We thus asked whether the enzyme might recognize alcohol substrates of which the aldehyde products could be cytotoxic; ERAB/HADH II catalyzed oxidation of a variety of simple alcohols (C2-C10) to their respective aldehydes in the presence of NAD+ and NAD-dependent oxidation of 17beta-estradiol. Addition of micromolar levels of synthetic Abeta(1-40) to purified ERAB/HADH II inhibited, in parallel, reduction of S-acetoacetyl-CoA (Ki approximately 1.6 microM), as well as oxidation of 17beta-estradiol (Ki approximately 3.2 microM) and (-)-2-octanol (Ki approximately 2.6 microM). Because micromolar levels of Abeta were required to inhibit ERAB/HADH II activity, whereas Abeta binding to ERAB/HADH II occurred at much lower concentrations (Km approximately 40-70 nM), the latter more closely simulating Abeta levels within cells, Abeta perturbation of ERAB/HADH II was likely to result from mechanisms other than the direct modulation of enzymatic activity. Cells cotransfected to overexpress ERAB/HADH II and betaAPP(V717G) generated malondialdehyde-protein and 4-hydroxynonenal-protein epitopes, which were detectable only at the lowest levels in cells overexpressing either ERAB/HADH II or betaAPP(V717G) alone. Generation of such toxic aldehydes was not observed in cells contransfected to overexpress Y168G/K172G-altered ERAB and betaAPP(V717G). We conclude that the generalized alcohol dehydrogenase activity of ERAB/HADH II is central to the cytotoxicity observed in an Abeta-rich environment.     

GaN Nanorods Catalyzed with Mo: Effect of Ammoniating Time on Microstructure,Morphology, and Optical Properties

GaN nanorods have been successfully grown on Si (111) substrates by magnetron sputtering through ammoniating Ga₂O₃ thin films catalyzed with Mo. The influence of the ammoniating time on the growth of GaN nanorods was analyzed, in particular, by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, Fourier transform infrared (FT-IR) spectrometer, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectrum. The results demonstrate that the GaN nanorods are single crystal with hexagonal wurtzite structure, which have high crystalline quality. The GaN nanorods after ammoniation at 1223 K (950 °C) for 20 minutes have good emission properties and the highest crystalline quality with 100- to 200-nm diameter and several-micron length. The growth direction of these nanorods is along the orientation of (100) crystal plane. A small red shift occurs because of the band-gap change caused by the tensile stress of the one-dimensional GaN nanorods along the axial direction.     

Formation cross sections of nuclei with (n,2n) reactions

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在线Nielsen源的研制

描述如何简单地把标准Ｎｉｅｌｓｅｎ源必建成在线离子源，对它的一些性能进行测试并与标准离子源作了比较，讨论了它们的判别和产生的原因。实验结果表明，两离子源的放电特性无差别，改建后的离子源可考虑用来进行整体靶离子源试验。     

低温核供热堆保护系统的研究

高可靠性的保护系统是核供热堆安全可靠运行的重要保证。本文介绍了围绕核供热堆保护系统所开展的设计和研究工作。着重讨论了核供热堆的安全特性;保护系统的功能,保护参数的选择以及保护系统的基本结构。最后简要介绍了目前正在进行的一种新型保护系统的设计方案。