基于氨基酸的新型树枝状色谱置换剂的合成及性能

高效置换剂的设计与合成一直是置换色谱发展的重要方向。采用固相合成方法合成了新型树枝状聚电解质置换剂Phe-D和Leu-D,并与置换剂BAEE进行了对比研究。研究结果显示,置换剂的动态亲和性随着lgΔ值增大而降低。在lgΔ<0.845时,BAEE具有最高的动态亲和力;而随着lgΔ进一步升高,Phe-D展现出最强的动态亲和力,这种趋势一直维持至lgΔ值达到3.08。蛋白质的静态置换实验表明,新型置换剂对蛋白质具有更高的置换百分率。这种高置换率主要源于置换剂中伯胺基团数量的增加;同时,Phe-D分子中苯基的引入使模型蛋白的置换百分率提高了70%,展示了苯基对蛋白质置换的促进作用。     

Osmium‐Catalyzed Selective Oxidations of Methane and Ethane with Hydrogen Peroxide in Aqueous Medium

Various transition metal chlorides including FeCl₃, CoCl₂, RuCl₃, RhCl₃, PdCl₂, OsCl₃, IrCl₃, H₂PtCl₆, CuCl₂ and HAuCl₄ were studied for the selective oxidations of methane and ethane with hydrogen peroxide in aqueous medium. Among the metal chlorides investigated, osmium(III) chloride (OsCl₃) exhibited the highest turnover frequency (TOF) for the formation of organic oxygenates (mainly alcohols and aldehydes) from both methane and ethane. For the OsCl₃‐catalyzed oxidation of methane with hydrgen peroxide, methyl hydroperoxide was also formed together with methanol and formaldehyde. The effects of various kinetic factors on the catalytic behavior of the OsCl₃‐H₂O₂ system were investigated, and TOF values of 12 and 41 h⁻¹ could be obtained for oxygenate formation during the oxidations of methane and ethane, respectively. In the presence of OsCl₃, NaClO, NaClO₄ or NaIO₄ as oxidant was incapable of oxidizing methane and ethane to the corresponding oxygenates, and the use of tert‐butyl hydroperoxide (TBHP) instead of H₂O₂ provided remarkably lower rates of formation of oxygenates. UV‐Vis spectroscopic measurements suggested that OsCl₃ was probably oxidized into an Os(IV) species by H₂O₂ in aqueous medium, and the Os(IV) species might be involved in the oxygenation of methane or ethane. The result that the conversions of both methane and ethane to oxygenates were suppressed by the addition of a radical scavenger suggested that the reactions proceeded via a radical pathway.     

Effects of thermal oxidation conditions of silicon electrodes on cathodic electrochemiluminescence of Ru(bpy)3 chelate

Hot electrons emitted from thin oxide film-coated heavily doped silicon electrodes by cathodic pulse polarization can induce electrochemiluminescence from luminophores. The intensity of electrochemiluminescence produced at the electrode surface is dependent on the features of thin oxide films formed by thermal oxidation. As a preliminary study, we investigated the effect of thermal oxide growth conditions on the intensity of electrochemiluminescence produced at these electrodes, such as oxidation atmospheres, oxidation temperature, oxidation time and pre-treatment of wafers, using ruthenium(II) tris-(2,2′-bipyridine) chelate as a model luminophore. Optimal oxidation conditions of heavily doped silicon electrodes were obtained for the generation of intense electrochemiluminescence at this kind of silicon electrodes.     

西藏达龙钨钼多金属矿床地质特征及找矿前景

达龙钨钼多金属矿床地处西藏拉萨市墨竹工卡县境内,位于著名的冈底斯成矿带东段北侧,目前矿区内已探获金属资源量WO3 8.38万t、Mo 2.98万t、Cu+Pb+Zn 5.03万t。结合矿区最新地质工作成果,对区域地质背景、矿区地质特征、矿床地质特征进行了详细分析,并对矿床成因进行了探讨。研究表明：①矿体主要赋存于上二叠统旁那组浅变质砂岩和板岩中,Ⅱ#、Ⅲ-1#、Ⅲ-2#、Ⅳ-1#矿体为主矿体,呈厚大脉状、透镜状及薄脉状产出,受NE向达龙断裂带控制,围岩蚀变发育,蚀变分带明显,矽卡岩化与矿化关系密切;②达龙矿床成因类型为矽卡岩-热液脉型钨钼多金属矿床,成矿物质来源于岩浆,与燕山晚期碰撞型中酸性岩浆活动关系密切,成矿流体具有从高温、高盐度向低温、低盐度演化分异的特征。在上述分析的基础上,从地层、构造、岩浆岩等方面分析了矿区成矿条件并对找矿标志和找矿前景进行了讨论,认为矿区NE向断裂、地层与岩体接触外带、硅化及地表铁帽等蚀变地段、环形线性构造交叉同时硅化及铁化蚀变异常叠加区域、Cu-Pb-Zn-W-Mo异常及低电阻高极化异常为有利的找矿标志;矿区15#勘探线深边部、Ⅰ#、Ⅱ#矿化体北侧以及Ⅳ-1#矿体以南地段找矿潜力巨大,是矿区有利的找矿靶区。     

煤矿采动区煤层气井地面抽采设备体系成套化研究

地面钻井抽采煤矿采动区和采空区瓦斯是近年来逐步发展起来的瓦斯抽采新技术,是快速降低煤矿瓦斯最直接有效的途径。针对目前抽采现场受道路、场地等因素制约、在运输、安装等方面存在困难以及现场设备布置分散、不利管理和维护等问题,提出设备成套化的理论体系。该体系主要有真空泵、发电机、循环水箱、防火防爆等设备,所有设备撬装组合成一体式抽采设备,在有效解决以上问题的同时还具有对地形适应性强、占地面积小、减少设备安装及回收时间,提高工作效率、节约设备运输、安装及回收成本等优势,便于现场操作与管理。     

临近基坑开挖复合地基侧向力学性状离心试验研究

临近基坑开挖引起复合地基CFG桩变形和内力改变,现有理论缺乏对该问题的研究。通过开展离心模型试验,对临近基坑开挖条件下,复合地基变形、CFG桩内力和变形、土压力等分布和变化规律进行深入分析。结果表明：开挖引起CFG桩弯矩增大,近基坑桩增幅明显|开挖引起桩土不同步沉降,导致CFG桩上刺入褥垫层,桩受到褥垫层的“嵌固拉结”作用,同时远基坑桩、褥垫层、加载气囊一起提供了“摩擦拉结”作用,从而在近基坑桩上出现负弯矩|而远基坑处不均匀沉降小,“嵌固拉结”作用小,且“摩擦拉结”作用是利于正弯矩产生,桩上未出现负弯矩|开挖引起支护背后土压力分为增长区和减小区两部分,在上部土体中,土体卸荷,土压力减小,而下部土体受支护挤压,土压力有所增大|开挖引起地表沉降呈指数形式,临近基坑地表沉降最大,在显著变形区域内,支护水平位移基本呈直线形式,各阶段最大水平位移均出现在支护顶端|开挖引起的CFG桩水平变形大小和范围随距基坑边距离的增大而减小。     

浅谈某地铁区间联络通道的设计与施工

联络通道一般设置在地铁区间隧道中间,起连通、排水及防火等作用,其设计和施工是地铁区间的薄弱环节,文中主要探讨某地铁区间不良地质下联络通道设计与施工问题,先采用搅拌桩和素混凝土加固地层,然后在拱顶小导管超前支护下采用短台阶保留核心土环形开挖的方式进行矿山法开挖,边开挖边支护,并通过现场监测及时控制地表沉降,以确保施工安全...     

集聚区牵伸倍数对紧密纱综合性能的影响

探讨紧密纺集聚区牵伸倍数对不同线密度紧密纱综合性能的影响.通过改变牵伸胶辊、输出胶辊直径的大小,来改变集聚区的牵伸倍数,然后纺制不同线密度的精梳紧密纱,测试其成纱性能.结果表明:当集聚区牵伸倍数为1.07倍时,CJ 27.8 tex和CJ 18.2 tex纱的综合性能较好;当集聚区牵伸倍数为1.05倍时,CJ 9.7 tex和CJ 7.3 tex纱的综合性能较好.     

纳米介孔MCM-41-M/偶联剂体系对天然橡胶性能的影响

制备了天然橡胶(NR)/MCM-41-M、NR/偶联剂化学改性纳米介孔MCM-41-M、NR/MCM-41-M/偶联剂复合材料,研究了不同含量的MCM-41-M、不同种类偶联剂对MCM 41-M的改性以及偶联剂的添加方式对NR复合材料性能的影响.结果表明;MCM-41-M在NR中有明显的补强作用,当代替3份炭黑时NR基复合材料的拉伸强度达到最大值,比纯NR提高了12.7%。与MCM-41-M和KH-570直接添加到NR中相比,MCM-41-M经偶联剂KH-570改性使拉伸强度提高了50%。将MCM-41-M用偶联剂KH 570改性后添加到NR中,使NR的玻璃化转变温度升高、玻璃化转变区的损耗角减小、储能模量提高到最大。