用计算机模拟与X-射线衍方法研究几种卤化物熔盐的结构

传统的熔盐结构理论多以“伪晶格模型”为基础,虽能解释熔盐结构的某些规律，但“伪晶格模型”与熔盐的真实结构相差甚远。迄今为止较为止较为严格的熔盐溶液理论是径向分布函数理论。本工作以径向分布函数理论为基础，利用Monte Carlo计算机模拟与X-射线衍射方法计算和测定了几种卤化物熔盐的径向分布函数（RDF），并在此基础上对若干熔盐微观结构和某些热力学性质的问题进行了讨论。1、LaCl_3-KCl与La-LaCl_3-KCl熔体结构的Monte Carlo计算机模拟研究；2、高温液态X-射线衍射实验方法的建立；3、用高温液态X-射线衍射方法研究几种卤化物熔盐的结构。研究结果表明，熔盐的结构对摩尔体积的变化很敏感，由温度的降低而引起的熔盐摩尔体积的收缩会导致熔盐中相同离子对间的距离缩短。由于熔盐是由阴、阳离子组成的离子熔体，其离子间的主要作用是Coulomb作用，因此熔盐中阳离子的尺寸及其所带电荷的多少是熔盐结构变化的主要影响因素。

卤化物基质中3m~(2+)离子光谱性质的研究

3m~(2+)离子在红区和红外区可以产生4f~6组态内的f-f跃迁锐线发射和d-f跃迁宽带发射。在某些基质中，这两种跃迁形式可以同时存在。由于d-f跃迁是原于宇称允许的跃迁，所以其发射强度要比4f~n组态内的f-f跃迁强得多。这可以保证对泵浦的有效吸收，提高光泵效率。而4f~n组态内部的f-f跃迁可以实现激光振荡，有利于提高储能降低阈值。所以研究3m~(2+)离子的光谱性质及其影响因素对于寻找和设计新的激光和发光材料有着重要意义。近年来，低价稀大离子的价态问题一直是人们力求探讨的问题，3m~(2+)离子具有极强的还原性和不稳定性，因此关于它的价态研究更具有特殊的意义。本论文采用了几种较简单的方法合成了三十种掺杂3m~(2+)离子的磷光体，分别经x－射线。荧光光谱等实验证实。其中有二十种未见过文献报道。在BaMgF_4:3m~(2+)等十七种体等中研究了基质格位的对称性，对于3m~(2+)离子f－f跃迁性质的影响。如果3m~(2+)离子占据其质中有反演对称中心的点群位置，只有f－f磁偶极跃迁是可能的。这时，~5Do→~7F_1发射线最强。如果3m~(2+)离子占据基质中无反演对称中心的点群位置，f－f磁偶极跃迁和受迫电偶极跃迁都是可能的，这时~5Do→~7Fo发射线最强。在KMgF_3:3m~(2+)等四种体系中研究了电荷补偿效应对3m~(2+)离子f－f跃迁性质的影响。如果3m~(2+)离子取代基质中的一价阳离子，电荷补偿效应使3m~(2+)离子的局部对称性降低，结果f－f跃迁发射线增多。在NaMgF_4:3m~(2+)体系中研究了基质晶体构形变化对3m~(2+)离子f－f跃进性质的影响。NaMgF_3:3m~(2+)由立方相变为正多相时，3m~(2+)离子的点对称性降低，结果出现了~5Do→~7F_3、~5Do→~7F_4两组新线。讨论了晶场强度和化学键性质对于3m~(2+)离子跃迁形式的影响。在有小半径或高正电荷阳离子作为中间阳离子的复合氟化物体系中，3m~(2+)离子周围的晶场变弱，3m－F的共价性降低，结果不能产生d-f跃宽带发射，只能产生f－f跃迁锐线发射。在某些共价性较强的碱金属卤化物和碱S金属卤化物基质中，3m~(2+)离子受到较强的共价作用，这种作用产生主影响，结果能够产生3m~(2+)离子的d-f跃迁宽带发射。在KxNo_1-xMgF_3:3m~(2+)、KMgF_3-xClx:3m~(2+)、KMgF_(2.9)*0.1:3m~(2+) (X=F、Cl、Br、I)三种体系中研究了基质组成变化对3m~(2+)离子f－f跃迁发射强度的影响。在形成化合物或固熔体的条件下，基质组成变化如果导致了3m~(2+)离子对称性降低，3m~(2+)离子的f－f跃迁发射就增强。和阳离子组成的变化相比，阳离子变化对3m~(2+)离子f－f跃迁发射强度影响更大。和正交体等相比，立方体系中基质组成变化对3m~(2+)离子f－f跃迁发射强度的影响更大。在BaCl_2:3m~(2+)等六种体系中讨论了激活剂浓度变化对3m~(2+)离子发射强度的影响。3m~(2+)离子浓度萃取的临界值一般在0.02mol左右，在临界浓度为，随激活剂浓度的增加，3m~(2+)离子的发射强度增大。研究了高温分解3mF_3法制备KMgF_3:3m~(2+)过程中3m(III)→3m(II)的价态转变。由于基质反应的存在，产生了某些局部化学因素，有利于3mF_3的分解，实现了3m(III)→3m(II)的价态转化。在某些复合氟化物和碱S金属氟卤化体系中研究了基质结构因素对于3m~(2+)离子价态的影响。得出了稳定3m~(2+)离子的基质条件为：①基质中含有半径接近3m~(2+)离子的一价或二价阳离子② 复合基质的形成速度要快。找出了KMgF_3、NaMgF_3、BaClF、BaBrF等四种特别能够稳定3m~(2+)离子的基质。在MLnFs(M=Ca Sr Ba Ln=La Crd)考定了几种合成方法对于3m(III)→3m(II)价态转化的影响，其中3m粉还原法为最佳方法。

La-Ba-Cu-Sn-O钙钛矿型多元复合氧化物的制备、组成、结构、电学性质和气敏性质的研究

本文合成了LaBa_2Cu_(3-x)Sn_xO_(6.5) + x (x = 0.2; 0.5; 0.7; 1.0; 1.2; 1.5; 1.7; 2.0; 2.2; 2.5; 2.7; 3.0)系列，2aBaCu_(2-x)Sn_xO_(4.5) + x (x = 0; 0.2; 0.5; 0.7; 1.0; 1.2; 1.5; 1.7; 2.0)系列和La_3Cu_(3-x)Sn_xO_(7.5) + x (x = 0.5; 1.0; 1.5; 2.0; 2.2; 2.5; 2.7)系列等二十八个新复合氧化物。这三个系列二十八个新复合氧化物直至目前为止，文献上未见过报道。我们通过x-ray粉末衍射图分析了它们的结构，肯定了它们是新的单一化合物，计算了它们的晶胞参数并确定它们的所属晶系。元素化学分析表明，所有这些化合物均可用原始计算配比化学式表示。干湿两种合成方法所合成的结构相同。对于这三个系列二十八个瓣复合氧化物，我们选用LaBa_2-Cu_(3-x)Sn_xO_(6.5) = x (x = 0.5;1.0;1.5;2.0;2.5),LaBaCu_(2-x)Sn_xO_(4.5) = x(x = 0.5; 1.0; 1.5;2.0), La_3Cu_(3-x)Sn_xO_(7.5) + x (x = 0.5; 1.0; 1.5; 2.0; 2.5)等十四个化合物，对它们的低温，高温和高湿下的电阻率和导电类型进行了测试，绘得了它们的电阻率和温度的关系曲线。在一定温度下，一个系列内的化合物电阻率随锡的分子含量增加而增大。La_3Cu_(3-x)Sn_xO_(7.5) = x系统人物的电阻率明显大于其它二个系列相应化合物的电阻率。所有化合物在液氮至室温温区内，基本上呈半导体导电类型。在高温以上温区，当温度升至一定温度时之前，化合物呈本导体导电类型达到一定温度之后，当金属导电类型所有新复合氧化物在高温均属P型半导体。本文还研究了这三个系列化合物和将它们掺入二氧化锡中的气敏性能。结果表明：所有这类化合物和将它们掺入二氧化锡中作为添加剂做成的气敏材料，除LaBa_2Cu_(1.5)Sn_(1.5)O_8掺入SnO_2做成的气敏材料外，在本文实验条件下做成的气敏元件对氧化性和还原性气体均无或只有很差的气敏性。LaBa_2Cu_(1.5)Sn_(1.5)O_8作为添加剂掺入SnO_2中(摩尔比0.2:0.8; 0.1:0.9)所制得的气敏文件对高浓度(1%-10%)的一氧化碳，液化气和煤气具有很好的气敏线性响应，当加热电流为300mA时，酒精，汽油和石油醚等还原性气体基本上无干扰。实验表明当摩尔比为0.1:0.9时，材料的气敏性能最佳，但重现性较差，当摩尔比为0.2:0.8时，气敏性稍低，但重现性较好。本文还合成了La_xBa_(1-x)SnO_3(x = 0; 0.05; 0.10; 0.15, 0.20)系列化合物，并确定了它们的结构和所属晶系。从结构上分析我们认该系列化合物相互之间为置换固溶体。其晶胞参数随镧的加入量增加而减小。该系列均属几型半导体材料。我们利用该系列材料进行了过敏性研究。结果表明。由La_(0.1)Ba_(0.9)SnO_3制得的高热式气敏器件对低浓度酒精(<1000 ppm)有很好的气敏线性响应。在加热电流为250 mA时，基本上排除了煤气，一氧化碳，液化气和汽油等可燃性气体的干扰。但香烟烟雾对器件检测酒精有一定的影响。La_(0.1)Ba_(0.9)SnO_3气敏材料多添加1%而制得的器件，机械强度达到很好的效果，器件对酒精的灵敏度有降低，而响应浓度区间宽度增加近一倍，选择性几乎不变。该材料具有较好的实验重现性。该系列的其它化合物在本实验条件下所制得的器件对可燃性气体的敏感性较差。

铜（III）及相关化合物的合成和性质的研究，稀土复合氟化物电性、氧敏和氢敏性质

本论文包括两部分内容。第一部分为“Cu(III)及相关化合物的合成和性质的研究”；第二部分为“稀土复合氟化物的电性、氧敏和氢敏性质”。第一部分的主要内容有：1.制备了Na_4H[Cu(H_2TeO_6)_2]·17H_2O和Na_4K[Cu(HIO_6)_2]·12H_2O的Cu(III)单晶配合物。2.在比较相应的Cu(II)化合物的条件下，详细地研究了这二个Cu(III)配合物的电子光谱和Cu2p光电子能谱，由于价态升高，场强参数增大，Cu(III)化合物的d-d跃迁相对于Cu(II)化合物d-d跃迁，发生“蓝移”。3.成功地实现了用O_3和电化学方法对强碱溶液中Cu(II)配合物的氧化，获得了二个新的Cu(III)固态配合物Ba_4K[Cu(H_2TeO_6)_2] (OH)_4·6H_2O和Ba_3K[Cu(HIO_6)_2] (KOH)_(0.5)(OH)_2·8H_2O利用化学分析、磁学性质、电子光谱和Cu2p XPS，对这二个化合物进行了表征。4.对BaCuO_(2.5)的合成、电学性质、磁学性质、Cu(III) ESR和Cu2p XPS进行了研究。5.以Na_4K[Cu(HIO_6)_2]·12H_2O和BaCuO_(2.5)为参照物，用电子光谱和Cu2p XPS，确认了YBa_2Cu_3O_(7-5)中的高价态的铜。6.考察了以Cu（III）化合物作为Cu部分原料所合成的YBCO系超导材料的电学性质。第二部分的主要内容有：1.测试了元件“BiF_3(Bi)/Ce_(0.95)Ca_(0.05)F_(2.95)/Pt”的氧敏、氢敏等性能。从室温到130 ℃，元件的氧敏机理为“双电子反应”，电动势（EMF）与氧分压遵循Nernst关系式。室温时，元件对空气中100Pa或1000Pa氢气的响应时间仅为15秒或短于5秒；氢分压在16Pa～1000Pa范围内，EMF与氢分压的对数呈线性关系，斜率为-116mV/decade, 敏感机理表现为“混合电极电势”。元件具有良好的氢敏性能，并有一定的选择性。2.合成并测试了La_(1-x)Pb_xF_(3-x)(X = 0.00 ～ 0.15)的电导率，La_(0.95)Pb_(0.05)F_(2.95)的电导率最高，比LaF_3高约一个数量级。以La_(0.95)Pb_(0.05)F_(2.95)为固体电解质材料，Pd或Pt为敏感电极，BiF_3(Bi)或PbF_2(Pb)为参比电极，制成了四个元件。其中，“BiF_3(Bi)/La_(0.95)Pb_(0.05)F_(2.95)/Pt”具有最好的氧敏、氢敏性能。从室温到150 ℃，元件的EMF与1gPo_2附合Nernst关系式。150 ℃时，元件对氧气的响应时间仅为80秒。室温下，元件对空气中100Pa或1000Pa氢气的响应时间仅为75秒或15秒，元件的电动势EMF与氢分压的关系可表示为“E=E_o-96lgP_(H2)(mV)”。元件对CO有较差的敏感性能，而对空气中甲烷、乙烷或乙炔（≤1000Pa）不具敏感性能。3.合成并测试了Ln_(1-x)Pb_xF_(3-x)(Ln=Ce、Pr、Nd和Gd、Dy、Ho、Yb)的电性。前四个系列为离子导体材料，后三个系列可能为P型半导体。随着Ln原子序数增大，LnF_3导电性能变差；La~(3+)、Ce~(3+)、Pr~(3+)、Nd~(3+)与Pb~(2+)离子半径差异较小，LnF_3和PbF_2可以形成固溶体；而Gd~(3+)、Dy~(3+)、Ho~(3+)、Yb~(3+)与Pb~(2+)离子半径差异较大，LnF_3和PbF_2难以形成固溶体。

First charge collection and position-precision data on the medium-resistivity silicon strip detectors before and after neutron irradiation up to 2x10(14) n/cm(2)

Test strip detectors of 125 mu m, 500 mu m, and 1 mm pitches with about 1 cm(2) areas have been made on medium-resistivity silicon wafers (1.3 and 2.7 k Ohm cm). Detectors of 500 mu m pitch have been tested for charge collection and position precision before and after neutron irradiation (up to 2 x 10(14) n/cm(2)) using 820 and 1030 nm laser lights with different beam-spot sizes. It has been found that for a bias of 250 V a strip detector made of 1.3 k Ohm cm (300 mu m thick) can be fully depleted before and after an irradiation of 2 x 10(14) n/cm(2). For a 500 mu m pitch strip detector made of 2.7 k Ohm cm tested with an 1030 nm laser light with 200 mu m spot size, the position reconstruction error is about 14 mu m before irradiation, and 17 mu m after about 1.7 x 10(13) n/cm(2) irradiation. We demonstrated in this work that medium resistivity silicon strip detectors can work just as well as the traditional high-resistivity ones, but with higher radiation tolerance. We also tested charge sharing and position reconstruction using a 1030 nm wavelength (300 mu m absorption length in Si at RT) laser, which provides a simulation of MIP particles in high-physics experiments in terms of charge collection and position reconstruction, (C) 1999 Elsevier Science B.V. All rights reserved.

X射线及电子束照射对非洲紫罗兰叶片外植体不定芽再生的影响

采用X射线(电子束能量8MeV)及9MeV电子束对两个品系(MauveandIndikon)的非洲紫罗兰(Saintpauliaionahta)组培苗叶片外植体进行辐照处理,研究其组织增殖、芽分化及叶片形态学变化。结果表明,40Gy的X射线照射能使Mauve及Indikon的外植体新鲜组织增殖倍数为27.3和26.3,相同剂量的电子束照射抑制组织增殖能力不如X射线照射,增殖倍数为49.7和27.4。低于20Gy的X射线和电子束照射诱发非洲紫罗兰叶片外植体增殖变化的规律不同于剂量高于20Gy的照射,呈先降低后升高趋势。100Gy的电子束辐照处理使Mauve及Indikon的芽形成率降为3.7%和11.3%,而100Gy的X射线辐照处理其芽形成率分别为7.5%和64.1%。就Mauve而言,60Gy的电子束辐照处理后畸形小苗百分比高达22.2%,相同剂量的X射线辐照处理后为14.8%;而对于Indikon,40Gy的电子束辐照可使畸形小苗百分比升至35.2%,该剂量条件下X射线的百分比仅为5.8%。因此,本研究发现非洲紫罗兰叶片的电子束辐照的诱变效果要优于X射线辐照,电子束辐照非洲紫罗兰Mauve及Indikon叶片组织的推荐最佳诱变剂量为40—60Gy。

Modification of Fe/Cu Multilayers under 2-MeV Xe20+ Irradiation

Multilayers with a structure of Si/[Fe(10 nm)/CU(10 nm)](5) were deposited on Si(100) substrates and then irradiated at room temperature by using 2-MeV Xe20+. The modifications of the multilayers were characterized using a depth profile analysis of the Auger electron spectroscopy (AES) data and the evolution of crystallite structures of the multilayers were analyzed by using X-ray diffraction (XRD). The AES depth profiles indicated that de-mixing of the Fe and the Cu layers was observed at low ion fluences, but inter-mixing of the Fe and the Cu layers was found at high ion fluences and destroyed the layered structure of the multilayers. The obtained XRD patterns showed that, after irradiation by 2-MeV Xe20+ at; 2 x 10(16) ions/cm(2), the peaks of the multilayers related to a Cu-based fee solid solution and an Fe-based bee solid solution phase became visible, which implied that the inter-mixing at the Fe/Cu interface resulted in the formation of new phases. A possible mechanism of modification in the Fe/Cu multilayers induced by ion irradiation is briefly discussed.

Defect production in silicon carbide irradiated with Ne and Xe ions with energy of 2.3 MeV/amu

In the present work specimens of mono-crystalline silicon carbide (4H polytype) were irradiated to three successively increasing ion fluences ranging from 7.2 x 10(14) to 6.0 x 10(16) ions/cm(2) (corresponding to the peak displacement damage of 1, 4 and 13 dpa) with Ne and Xe ions respectively with the energy of 2.3 MeV/amu. The irradiated specimens were subsequently annealed at temperatures of 1173 and 1273 K. Defect structure was investigated with transmission electron microscopy (TEM) using a cross-sectional specimen preparation technique. The typical microstructures of the annealed specimens irradiated with Ne or Xe ions to high fluences are characterized by small gas bubbles in high concentration in the peak damage region and black dots and dislocation loops (located in the basal plane) in a shallower and broader depth region. Larger dislocation loops were observed in the Xe-ion irradiated specimen than in the Ne-ion irradiated specimen at the same peak damage level. The enhanced formation of dislocation loops in the case of Xe-ion irradiation is understandable by assuming stronger inclination of heavier inert-gas atoms to occupy substitute site in the peak damage region.

Observation of a pi h(9/2) circle times nu i(13/2) oblate band in Tl-188

Excited states in Tl-188 have been studied experimentally using the Gd-157(Cl-35;4n) reaction at a beam energy of 170 MeV. A rotational band built on the pi h(9/2) x nu i(13/2) configuration with oblate deformation has been established for Tl-188. Based on the structure systematics of the oblate pi h(9/2) x nu i(13/2) bands in the heavier odd-odd Tl nuclei, we have tentatively proposed spin values for the new band in Tl-188. The pi h(9/2) x nu i(13/2) oblate band in Tl-188 shows low-spin signature inversion, and it can be interpreted qualitatively by the two-quasiparticle plus rotor model including a J-dependent p-n residual interaction.

Synthesis and characterization of novel sulfonated polyimides from 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid

A novel sulfonated diamine monomer, 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid (BAPNDS), was synthesized. A series of sulfonated polyimide copolymers were prepared from BAPNDS, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) and nonsulfonated diamine 4,4'-diaminodiphenyl ether (ODA). Flexible, transparent, and mechanically strong membranes were obtained. The membranes displayed slightly anisotropic membrane swelling. The dimensional change in thickness direction was larger than that in planar. The novel SPI membranes showed higher conductivity, which was comparable or even higher than Nafion 117. Membranes exhibited methanol permeability from 0.24 x 10(-6) to 0.80 X 10(-6) cm(2)/s at room temperature, which was much lower than that of Nafion (2 x 10-6 CM2/s). The copolymers were thermally stable up to 340 degrees C. These preliminary results have proved its potential availability as proton-exchange membrane for PEMFCs or DMFCs.

3{1-[2-(-3-羟基-1-甲基-2-亚丁烯氨基)-苯亚氨基]-乙基}4-甲硫基-2,4-戊二烯-2-醇的不对称Schiff碱镍(Ⅱ)配合物的合成、结构和性质

由 5-(2-乙酰基-1-甲硫基-3-羰基-亚丁基)-丙二酸亚异丙酯 (1)与邻苯二胺及乙酸镍()经一步反应合成了3{1-[2-( -3-羟基-1-甲基-2-亚丁烯氨基)-苯亚氨基 ]-乙基} 4-甲硫基-2,4-戊二烯-2-醇(3)的不对称四齿 Schiff碱镍()配合物(2),X射线衍射结果表明,配合物 2属单斜晶系,P21/C空间群.a=1.1476(2)nm,b=1.1782(2)nm,c=1.4810(3)nm;β=111.73(2)°,V=1.8602(7)nm3,Z=4,Rf=0.0535.电化学(循环伏安)测定结果表明,该配合物在测定条件下(阳极峰电位为1.1)发生了不可逆的氧化-还原反应.

Alkali metal ions transfer across a water/1,2-dichloroethane interface facilitated by a novel monoaza-B15C5 derivative

In this paper, a novel monoaza-B15C5 derivative, N-(2-tosylamino)-isopentyl-monoaza-15-crown-5 (L), is used as an ionophore to facilitate alkali metal cations transfer across a water/1,2-dichloroethane (W/DCE) interface. Well-defined voltammetric behaviors are observed at the polarized W/DCE interfaces supported at micro- and nano-pipets except Cs+. The diffusion coefficient of this ionophore in the DCE phase is calculated to be equal to (3.3+/-0.2) x 10(-6) cm(2) s(-1). The experimental results indicate that a 1:1 (metal: ionophore) complex is formed at the interface with a TIC/TID mechanism. The selectivity of this ionophore towards alkali ions follows the sequence Na+ > Li+ > K+ > Rb+ > Cs+. The logarithm of the association constants (log beta(1)(0)) of the LiL+, NaL+, KL+ and RbL+ complexes in the DCE phase are calculated to be 10.6, 11.6, 9.0 and 7.1, respectively. The kinetic parameters are determined by steady-state voltammograms using nanopipets. The standard rate constants (k(0)) for Li+, Na+, K+ and Rb+ transfers facilitated by L are 0.54+/-0.05, 0.63+/-0.09, 0.51+/-0.04 and 0.46+/-0.06 cm s(-1), respectively. The pH values of aqueous solution have little effect on the electrochemical behaviors of these facilitated processes. The results predicate that this new type of ionophore might be useful to fabricate electrochemical sensor of sodium ion.