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.

稀土氟化物固体电解质的制备、结构及电学、传感性能的研究

我们利用湿法制备了单一稀土氟化物LnF_3(Ln = La 、Ce、Nd、Gd、Tb、Dy、Er、Yb、Y), 并采用高温固相反应制备了稀土掺杂氟化物Ln_(1-x)MxF_(3-δ)(Ln = La、Ce、Gd、Yb、Y M = Ca、Sr、Ba)。用X射张衍射方法研究了它们的晶体结构。对单一稀土氟化物，LaF_3、CeF_3、NdF_3为六方晶系，GdF_3、TbF_3、DyF_3、DrF_3、YbF_3、YF_3为正交晶系。对掺杂氟化物，La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Yb_(0.70)Sr_(0.30)F_(3-δ)为固溶体，Ce_(0.95)Ca_(0.05)F_(3-δ)的晶胞参数比CeF_3的略为变小；Gd_(0.85)Ca_(0.15)F_(3-δ)、Y_(0.71)Ca_(0.29)F_(3-δ)为新化合物，Gd_(0.85)Ca_(0.15)F_(3-δ)的晶体结构由GdF_3的正交晶系变为六方晶系，其晶胞参数为：a=3.973A, C=7.124A, γ=120°, Y_(0.71)Ca_(0.29)F_(3-δ)化合物的晶体结构与YF_3相同为正交晶系，晶胞参数却较小：a=3.683A、b=6.978A, c=3.396A。 我们对氟化物的烧结陶瓷片进行了直流电导率测量。对单一稀土氟化物，结果表明六方结构的化合物的电导率高于正交结构的，对于相同结构的氟化物，一般地，稀土离子半径越大，电导率越高；对于掺杂氟化物，由于二价碱土金属离子掺杂可以提高氟离子空位浓度，因此掺杂物的电异率均高于对应的单一稀土氟化物，其中Gd_(0.85)Ca_(0.15)F_(3-δ)掺杂后变成更利于离子导电的六方结构。采用压片工艺，以La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Gd_(0.85)Ca_(0.15)F_(3-δ)和Y_(0.71)Ca_(0.29)F_(3-δ)为固体电解质材料制备电位输出式氧传感器件，并利用调节N_2、O_2流量比控制氧分压的方法，对器件的敏感性能进行测试。结果表明该类器件可在150 ℃的低温下对氧气敏感，器件的输出电位差与氧分压的对数值有较好的线性关系。器件的响应时间在2分与9分之间。该类器件的敏感机理是：氧气先吸附敏感电极上，发生还原反应后生成的氧负离子在敏感电极与固体电解质界面上发生晶格置换反应，使得氧分压的改变通过快离子即氟离子在两个界面上（另一界面为参比电极与固体电解质界面）的电化学势差的变化与输出电位差值的改变联系起来，从而实现利用输出电位差测定氧分压的目的。根据使用的敏感电极材料，可以有单电子反应和双电子反应两种敏感机理。器件是由参比电极、固体电解质、敏感电极三个部分构成。我们采用固定其中二个部分的材料，改变第三个部分的用料的方法，对器件的敏感性进行了对比研究：A、我们首先固定固体电解质为Ce_(0.95)Ca_(0.05)F_(3-δ)、敏感电极材料为Pt黑，采用不同的参比电极材料Bi+BiF_3、Sb+SbF_3、Mg+MgF_2、Zn+ZnF_2制备了器件。性能测试结果表明使用Bi+BiF_3参比电极材料的器件稳定性和敏感性都比其它器件好。器件的输出电位差取决于参比电极氟化物的标准生成自由能的大小。B、固定Bi+BiF_3为参比电极材料，Ce_(0.95)Ca_(0.05)F_(3-δ)为固体电解质，使用不同的敏感电极材料Pt黑、Pd粉、Ag粉和RuO_2制备器件。性能测试结果表明：Pt材料器件的精确度较高，Pd材料器件的响应最快（2分），RuO_2材料器件的敏感性较好。使用Ag、RuO_2敏感电极材料的器件采用的是单电子反应敏感机理：O_2 + e <-> O_2~-, O_2~- + V_F + F_(F-bar)~- <-> O_(F-bar) + O_F + F_(F-bar)。而使用Pt、Pd敏感电极材料的器件采用双电子反应敏感机理：O_2 + 2e <-> 2O~-, 2O~- + F_(F-bar) <->O_(F-bar) + F~-。C、我们固定Bi+BiF_3为参比电极材料，Pt和RuO_2为敏感电极材料，使用La_(0.95)Ba_(0.05)F_(3-δ)、Ce_(0.95)Ca_(0.05)F_(3-δ)、Gd_(0.85)(Ca_(0.015)F_(3-δ)、Yb_(0.70)Ca_(0.29)F_(3-δ)制备了两个系列的器件。结果表明，无论是使用Pt还是使用RuO_2为敏感电极材料，都有下列的结论：用Ce_(0.95)Ca_(0.05)F_(3-δ)的器件的精确度较高，La_(0.95)Ba_(0.05)F_(3-δ)材料器件的敏感性最好，而Gd_(0.85)(Ca_(0.015)F_(3-δ的响应最快（Pt器件2分，RuO_2器件5分）。并未发现同时具备各种较好性能的器件，与敏感电极材料对器件性能的影响相比，固体电解质材料的影响要小。对于材料完全相同的器件，我们还对工艺条件影响作了初步研究。制备器件的工艺条件由于各种难以控制的因素不会每次、每批完全相同，工艺条件的差别也会影响器件的各方面性能。研究结果表明，工艺差别对器件的输出电位差值和响应时间的影响较大，对敏感性能的影响则较小。

（一）2，4－二甲基戊二烯基烯土氯化物的合成及其对丁二烯的聚合活性（二）酞菁铜衍生物 LB 膜材料的合成及其气敏特性

本文通过元素分析，红外光谱，热失重分析，质谱。X 光电子能谱的测定以及对化合水解产物的分析。确认合成了下列三种新型 2，4－二甲基戊二烯基稀土氯化物。（I）[2,4-(CH_3)_2C_5H_5]LnCl_2·nTHF (2,4-(CH_3)_2C_5H_5 = 2, 4－二甲基戊二烯基；Ln = Pr, Nd, Sm, Gd; n = 3)。（II）[2,4-(CH_3)_2C_5H_5]LnCl_2·nTHF (Ln = Pr, Nd; n = 2, 3)。（III）[2,4-(CH_3)_2C_5H_5]LnCl_2·nTHF (Ln = Nd, Sm; n = 1)。在稀土金属有机化合物中尚未见此类化合物的报导。化合物的质谱分析结果表明，配位的四氢呋喃分子容易从配合物分子中脱落，形成带一个四氢呋喃，甚至不带四氢呋喃的配合物。说明配合物分子中不带四氢呋喃的形式是较稳定的。化合物的 X 光电子能谱结果表明化合物不是混合物。化合物水解产物的定量气相色谱分析进一步证实所合成的化合物为我们所预期的产物。实验结果表明，单体转化率受溶剂影响较大。在以环戊烷为溶剂的聚合反应中，聚合活性较高。而以甲苯为溶剂的聚合反应中，其聚合活性较低。在主催化剂不变的条件下，改变 Al/Nd 摩尔比，单体的转化率有明显的变化。同一 Al/Nd 摩尔比，不同催化剂用量也对单体的转化率有较大的影响。对聚合物的微观结构分析表明，溶剂，铝钕摩尔比催化剂用量对聚丁二烯的顺－1，4 含量均有影响，但影响不大。

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。

X射线双晶衍射在分布布喇格反射镜研制中的应用

利用X光双晶衍射的动力学理论对垂直腔面发射激光器(VCSEL)的分布布喇格反射镜(DBR)的特性曲线进行了模拟研究。从中得到DBR AlAs/Al_xGa_(1-x)As的厚度及组分x值,应用所得到的这些数值进行光学薄膜反射谱的模拟计算,并与实验所测得的DBR反射谱进行比较,得到了证实。应用这套方法指导VCSEL外延片的生长,获得了良好的结果。

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.

重离子与X射线沿水介质入射深度诱导癌细胞失活的比较

采用Hela、B16两种细胞分别研究了X射线和重离子在水介质中入射的深度与相应细胞的存活率 (1-失活率 )。结果表明 :X射线与重离子在入射深度与细胞存活关系上有明显不同的变化规律。X射线的入射深度与其细胞存活率呈高度正相关性 ,r =0 .92 ;而重离子通过路径的细胞损伤率较小、且有一个细胞存活较高的坪区 (86 %— 92 % ) ,到射程末端细胞损伤率剧增 ,出现倒Bragg峰。提示 :重离子在深层肿瘤治疗上具有比X射线好的深度治疗分布

~(129)Xe~(q+)激发Mo表面产生的X射线谱；X-ray spectrum emitted by the impact of ~(129)Xe~(q+) on Mo surface

研究了高电荷态离子129Xeq+(q=25,26,27)入射金属Mo表面产生的特征X射线谱.实验结果表明,在束流强度小于120nA条件下,高电荷态离子129Xeq+可以激发Mo的L壳层特征X射线谱.单离子X射线相对产额可达10-8量级,特征X射线的相对产额随入射离子的动能和电荷态(势能)的增加而增加.通过Mo原子的Lα1特征X射线谱,利用Heisenberg不确定关系对Mo原子的第M能级寿命进行了估算.

Studies of K-shell x-ray energy shifts induced by MeV/u heavy ions

This paper reports that the K x-ray spectra of the thin target 47Ag, 48Cd, 49In and 50Sn were measured by an HPGe semi-conductor detector in collisions with 84.5 MeV 6C4+ ions. Our experiment revealed the Kα x-ray energy shifts were not obvious and the Kβ1 x-ray energy shifts were about 90∼110 eV. The simple model of Burch et al has been previously used to calculate the K x-ray energy shifts due to an additional vacancy in 2p orbit. The present work extends the model of Burch to calculate the x-ray energy shifts of multiple ionized atoms induced by heavy ions with kinetic energy of MeV/u. In addition to our experimental results, many other experimental results are compared with the calculated values by using the model.

Kinetics of acetic acid esterification with 2-ethoxyethanol over an Al-pillared clay catalyst

The Al-pillared clay catalyst obtained by exposing activated clay powder to sulfuric acid and aluminium salts and calcining in air at 373-673 K, was found to be highly active for the title reaction. The results indicated that pillared layer clay of the mixed oxide has been employed as parent catalysts for their definite structure and special properties which can be modified by the substitution of L and B acid sites cations. Solid acid catalyst of Supported aluminium was found to be highly active and selective at the 373-473 K temperature range for heterogeneous esterification. The activity is mainly attributed to the Lewis (and a considerably small number of Bronsted) acid sites whose number and strength increased due to pillaring. The water produced in the esterification can be induced by Al3+, which makes the catalyst surface to form strong B acid. Their acidities are obtained by pH measurement. If only B acid sites are > 70%, and pH < 1 in the 2-ethoxyethanol, there exists an activity of esterification. The used catalyst gave identical results with that of the fresh one. X-ray diffraction spectra show that the composition and active phase of the used catalysts are the same as the fresh ones. The kinetic study of the reaction was carried out by an integral method of analysis. The kinetic equation of surface esterification is y = 2.36x - 0.98.

Electrochemiluminescence from tris(2,2 '-bipyridyl)ruthenium(II)-graphene-Nafion modified electrode

An electrochemiluminescence (ECL) sensor based on Ru(bpy)(3)(2+)-graphene-Nafion composite film was developed. The graphene sheet was produced by chemical conversion of graphite, and was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and Raman spectroscopy. The introduction of conductive graphene into Nafion not only greatly facilitates the electron transfer of Ru(bpy)(3)(2+), but also dramatically improves the long-term stability of the sensor by inhibiting the migration of Ru(bpy)(3)(2+) into the electrochemically inactive hydrophobic region of Nafion. The ECL sensor gives a good linear range over 1 x 10(-7) to 1 x 10(-4) M with a detection limit of 50 nM towards the determination of tripropylamine (TPA), comparable to that obtained by Nafion-CNT.

Organolanthanides with 3-(2-pyridylmethyl) indenyl ligands: synthesis, crystal structures and catalytic activities of divalent complexes for epsilon-caprolactone polymerization

Reaction of 3-(2-pyridylmethyl)indenyl lithium (1) with LnI(2)(THF)(2) (Ln = Sm, Yb) in THF produced the divalent organolanthanides (C5H4NCH2C9H6)(2)Ln(II)(THF) (Ln = Sm (2), Yb (3)) in high yield. 1 reacts with LnCl(3) (Ln = Nd, Sm, Yb) in THF to give bis(3-(2-pyridylmethyl)indenyl) lanthanide chlorides (C5H4NCH2C9H6)(2)Ln(III)Cl (Ln = Nd (4), Sm (5)) and the unexpected divalent lanthanides 3 (Ln = Yb). Complexes 2-5 show more stable in air than the non-functionalized analogues. X-ray structural analyses of 2-4 were performed. 2 and 3 belong to the high symmetrical space group (Cmcm) with the same structures, they are THF-solvated 9-coordinate monomeric in the solid state, while 4 is an unsolvated 9-coordinate monomer with a trans arrangement of both the side-arms and indenyl rings in the solid state. Additionally, 2 and 3 show moderate polymerization activities for F-caprolactone (CL).