977 resultados para Modèle cholestatique Mn-BR
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目前,聚合物电解质膜燃料电池和直接甲醇燃料电池的氧电极基本上都用Pt/C作为电催化剂。当铂的载量较多时,氧还原的催化活性较高,但电池成本很贵。铂的载量较少时,氧还原反应的速度较慢,因而限制了燃料电池的性能。为了提高氧还原电催化剂的活性,减少铂的用量,降低成本,近年来对碳载铂的二元
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研究了在多官能团单体异氰尿酸三烯丙酯(TAIC)存在下,辐射对PP/BR共混体系的影响,并用SEM,DSC和动态力学性能等技术对其进行了表征。结果显示,辐射引发TAIC参与的界面反应改变了PP/BR的形态结构,增强了两相的界面粘接,改善了相容性,提高了力学性能。
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合成了一系列结构为层状ABO3的复合氧化物La4BaCu5-xMxO13(M=Mn,Co),并利用XRD、X射线能谱、氧程序升温脱附和化学分析方法对它们的结构和活性氧种进行了研究。XRD分析结果表明:它们的结构为五层的ABO3结构。活性氧种的研究表明La4BaCu5O13中掺杂Mn或Co之后,样品中明显存在的MCu(M=Mn,Co)之间的协同作用,并且CuMn之间协同作用明显比CuCo的强。
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研究了在多官能团单体—三烯丙基异氰酸酯存在下,共混体系聚丙烯/1.4-聚丁二烯橡胶的辐射效应,用DSC,动态粘弹谱对其进行表征。结果显示,三烯丙基异氰酸酯主要分布于聚丙烯/1.4-聚丁二烯橡胶共混物的界面处,在高能射线作用下,被引发参与界面反应,从而改善了共混体系的相容性,增强了界面粘接,提高了共混物的力学性能。
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ZnGa_2O_4是具有尖晶石结构的复合氧化物,是一种重要的阴极射线发光材料。同时由于它的光透明性和金属导电性,它又可以用作液晶显示和太阳能电池的透明电极。ZnGa_2O_4的能隙大约为4.4ev,作为一种低电压发光材料,它有可能取代以ZnS为基础的低电压阴极射线发光粉而用于新型的真空平板阴极射线管中。文献[1-2]中报导的ZnGa_2O_4以及激活离子掺杂的ZnGa_2O_4大部分由传统的固相法
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The surface of superground Mn-Zn ferrite single crystal may be identified as a self-affine fractal in the stochastic sense. The rms roughness increased as a power of the scale from 10(2) nm to 10(6) nm with the roughness exponent alpha = 0.17 +/- 0.04, and 0.11 +/- 0.06, for grinding feed rate of 15 and 10 mu m/rev, respectively. The scaling behavior coincided with the theory prediction well used for growing self-affine surfaces in the interested region for magnetic heads performance. The rms roughnesses increased with increase in the feed rate, implying that the feed rate is a crucial grinding parameter affecting the supersmooth surface roughness in the machining process.
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With XRD, R-T, and ac chi measurements a comparative study on the doping effects of 3d elements in Bi(1.5)Pb(0.2)Sr(2)Ca(2)Cu(2.8)M(0.2)O(y) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Zn) has been carried out. The effects of the former five members are significantly different, both on phase formed and on T-c, from the latter four. It seems that the effect on phase stabilization correlates with the valency of the doped cation. In connection with the instability of the 2223 phase, the correlation has been discussed.
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研究了4种共混比的LnBR/SBR共混生胶、混炼胶及硫化胶的性能,并与NiBR/SBR共混胶进行了对比。结果表明,共混生胶的ML均低于LnBR及SBR;当LnBR/SBR共混比大于20/80时,呈现2个Tg;而大于80/20则出现应变诱导结晶现象。LnBR/SBR共混混炼胶的ML、剪切应力、出口膨胀及硫化速度均低于NiBR/SBR共混胶,挤出物外观优于后者;共混硫化胶的拉伸强度、热空气老化、拉伸疲劳、湿滑、耐磨等性能均明显优于后者,生热和透气率高于后者。
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A modified method for dispersing platinum particles on a glassy carbon (GC) electrode was investigated. The ultramicro Pt particle-modified electrode obtained exhibited high catalytic stability and activity towards the oxidation of some halide ions (Br-, I-) and inorganic sulfur species (S2O32-, SO32- and SCN-). These anions were separated and detected by using ion chromatography and electrochemical detection via this novel dispersed Pt particles-GC working electrode. The detection limits were 20 ng/ml for Br-, 1.0 ng/ml for I-, 10 ng/ml for SO32- and 4.0 ng/ml for SCN-. This method was employed for the analysis of industrial and environmental waste waters.
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用 AIKα(hυ=1486.6 eV)X-射线测量 15种四卤合金属酸十六铵的光电子能谱.讨论了这些化合物的Zn(2p)、Co(2p)、Cu(2p)、Mn(2p)、Cd(3d)、Cl(2p)、Br(3d)、I(3d)、N(1s)的芯能级结合能的化学位移.根据Pauling电负性讨论了这些数据和计算电荷的关系.讨论了配位体X(Cl,Br,I)、中心离子M(Zn,Co,Cu,Mn,Cd)和质子化十六胺(C16H33NH3)+的关系.
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研究了稀土顺丁橡胶(Ln—BR)与天然橡胶(NR)以不同比例共混后生胶、混炼胶和硫化胶的性能,并与相同条件下的镍系顺丁橡胶(Ni-BR)/NR共混胶的性能进行了对比.结果表明,共混胶随Ln—BR用量的增大,ML_(1+4)~(100℃)降低,工艺行为良好,硫化胶力学性能、磨耗、湿滑指数和生热值下降,并且Ln—BR/NR硫化胶的抗湿滑性和动态疲劳性均优于Ni-BR/NR硫化胶.
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采用机械共混法,在弹性体用量为5%~25%时,研究了SBS,SBR,BR分别对HIPS的增韧效果。SBS可使HIPS的冲击韧性大幅度提高,并随SBS含量增加显著上升。SBR也能提高HIPS的冲击韧性,但幅度不大。BR的加入使HIPS的冲击韧性下降。前两者的冲击试样断面平整而光洁,有明显的应力发白现象,属韧性断裂,后者的断面粗糙不平,无应力发白现象,属脆性断裂。改性HPS的形态随着弹性体的不同以及含量的变化均有不同特点,与冲击韧性的变化相对应。
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Three series of samples LaMnyCo1-yO3+/-lambda, LaFeyMn1-yO3+/-lambda, and LaFeyCo1-yO3+/-lambda (y = 0.0 to 1.0) with Perovskite structure were prepared by an explosion method different from the generally used ceramic techniques. The variation of crystal
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本文在pH5.5的乙酸-乙酸钠介质中,对以5-Br-PADAP作指示剂络合滴定法连续测定锌和铜进行了研究,对滴定的pH值及指示剂用量进行了选择,试验了锌、铜不同配比的滴定结果,研究了共存离子的干扰。实验表明,用5-Br-PADAP作指示剂、EDTA作滴定剂连续测定锌和铜,滴定终点颜色变化敏锐,准确度高,锌和铜均在0~20mg范围内与EDTA用量成正比,锌、铜比例在1:10~10:1范围内相互无影响,方法用于标样及金矿中锌、铜的连续测定,结果满意。
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用Sol-Gel法合成了LaMO_3(M=Fe,Cr,Mn,Co)超微粉末.X射线衍射分析表明,不同焙烧温度下所合成的化合物均为单相.SEM分析表明,粒子呈球形,室温电阻率测量表明,电阻率随粒度的变化呈两种类型:LaFeO_3,LaCrO_3随粒度的增大,电阻率增加;而LaMnO_3,LaCoO_3随粒度的增大,电阻率减小.