Conductivity and band alignment of LaCrO_3/SrTiO_3(111) heterostructure

In this work,we investigate the electrical transport property and electronic structure of oxide heterostructure LaCrO_3/SrTiO_3(111).The interface grown under relatively low oxygen partial pressure is found to be metallic with a conducting critical thickness of 11 unit cells of LaCrO_3.This criticality is also observed by x-ray photoelectron spectroscopy,in which the Ti~(3+) signal intensity at the spectrum edge of the Ti-2p_(3/2) core level increases rapidly when the critical thickness is reached.The variations of the valence band offset and full width at half maximum of the core-level spectrum with LaCrO_3 thickness suggest that the built-in fields exist both in LaCrO_3 and in SrTiO_3.Two possible origins are proposed:the charge transfer from LaCrO_3 and the formation of a quantum well in SrTiO_3.Our results shed light on the understanding of the doping mechanism at the polar/non-polar oxide interface.Moreover,due to the interesting lattice and spin structure of LCO in the(111) direction,our work provides a basis for further exploring the novel topological quantum phenomena in this system.     

几类甲基丙烯酸pH—敏感水凝胶的溶胀行为研究

本文合成了以甲基丙烯酸为基础的各类ｐＨ敏感型水凝胶,并研究它们的溶胀行为。初步探索了水凝胶的组成与其ｐＨ敏感的关系,比较了阴离子型水凝胶、阳离子型水凝胶和两性水凝胶的溶胀热力学动力学行为,得出了两性水凝胶在整个ｐＨ范围内都有一定的溶胀比,且在ｐＨ中性时,其溶胀速率要高于相应的阴离子型和阳离子型水凝胶。     

Synthesis and Structure of One Novel Polyoxometalate Compound Connected via Cerium(III) Cation with Three-dimensional Framework H_2{[K(H_2O)_2]_2[Ce(H_2O)_5]_2(H_2Mo_(1.16)W_(10.84)O_(42))}·8H_2O

One novel polyoxometalate compound connected via trivalent cerium cation as bridge H2{[K(H2O)2]2[Ce(H2O)5]2(H2Mo1.16W10.84O42)}·8H2O 1 was designed and synthesized in aqueous solution. X-ray diffraction analysis reveals that the structure of 1 is a three-dimensional framework assembled from the arrangement of H2Mo1.16W10.84O42 (named paradodecmetalate-B) and Ce(H2O)53+ containing two planes, which are constructed through the unification of H2Mo1.16W10.84O4210- and Ce(H2O)53+ along the [100] and [001] directions. Crystal data: H96Ce4K4Mo2.32O128W21.68, Mr = 7074.89, monoclinic, P21/n, a = 12.5037(17), b = 17.002(2), c = 12.7473(17) A, β = 105.966(2)°, V = 2605.4(6) 3, Z = 1, Dc = 4.509 g/cm3, F(000) = 3132, μ = 26.098 mm-1, R = 0.0377 and wR = 0.0789 (I > 2σ(I)).     

铀污染过滤器芯钙钛锆石玻璃陶瓷固化研究

以B2O3、CaO、TiO2和ZrO2为固化原料,以Ce作为铀的模拟核素,开展了铀污染过滤器芯钙钛锆石玻璃陶瓷固化体的影响因素研究,利用XRD、SEM、ICP-MS等分析方法对固化体进行了结构性能表征。研究结果表明,通过向铀污染过滤器芯中添加成核剂可以形成钙钛锆石玻璃陶瓷固化体,其最佳晶化温度约为1 050℃;钙钛锆石玻璃陶瓷中晶体的形成与B2O3、TiO2及ZrO2添加量密切相关,其最佳含量分别为8.09%、9.17%和7.05%;钙钛锆石玻璃陶瓷固化体中Ce元素的归一化浸出率低于10-10g·cm-2·d-1数量级,固化体对模拟核素Ce具有良好的包容性能。     

Synthesis,Structure,and Magnetic Property of One Snake-shaped Copper（Ⅱ）-organic Compound：Cu[Cu_2（PP）_2]（CBPC）_2]·2（H_2O）

One novel copper(II)-organic compound,namely Cu[Cu2(PP)2](CBPC)2]·2(H2O)(1,H2CBPC = 1-[(2'-carboxybiphenyl-4-yl)methyl]-2-propylimidazole-4-carboxylic acid,HPP = 3-(2-pyridyl)pyrazole),was designed and synthesized under hydrothermal conditions.X-ray diffraction analysis reveals that two Cu(II)ions in the quasi-planar dimmer of [Cu2(PP)2] are linked by the carboxylate oxygen atoms on the phenyl ring and the imidazole ring,respectively,yielding one snake-shaped structure.Magnetic measurements reveal that compound 1 shows the strongly antiferromagnetic property.Crystal data of 1:C58H52Cu3N10O10,Mr = 1239.72,monoclinic,P21/c,a = 14.900(7),b = 15.029(7),c = 12.308(6),β = 102.519(9)o,V = 2691(2)3,Z = 2,Dc = 1.530 g/cm3,F(000)= 1274,μ = 1.246 mm-1,R = 0.0416,wR = 0.0780(I > 2σ(I))and S = 0.999.     

以乙烯基酯树脂为多元醇制备聚氨酯硬质泡沫塑料的研究

研究了用乙烯基酯树脂（ＶＥＲ）直接代替通常的聚醚或聚酯型多元醇制备聚氨酯（ＰＵ）硬质泡沫塑料的可能性。实验结果表明,发泡配方中促进氨酯化反应的催化剂Ｎ,Ｎ－二甲基环己胺能与ＢＰＯ复合形成室温引发体系,加速ＶＢＲ的共聚合反应,影响了ＰＵ硬质泡沫塑料形成过程中的发泡与凝胶反应,导致泡了孔骨架基材的交联密度较低,泡孔结构不规整,并显示出较差的物理性能。以ＡＩＢＮ为引发剂时,反应初期主要进行氨酯化反应;仅     

巢式十一顶铂硼烷簇合物的合成与晶体结构

[PtCl₂(PPh₃)₂]与B₁₀H₁₀^2－在异丙醇中回流反应, 得到3个巢式十一顶铂十硼烷簇合物: [(PPh₃)₂PtB₁₀H₁₁-9-O-i-Pr] (1), [(PPh₃)₂PtB₁₀H₁₀-8,10-(O-i-Pr)₂] (2)和[(PPh₃)₂PtB₁₀H₁₁-8-O-i-Pr] (3). 簇合物1～3都具有PtB₁₀多面体骨架结构, 其中Pt原子位于敞开的PtB₄面上, 且与4个B原子成键, 每个Pt原子还与2个PPh₃基团中的P原子成键. 将溶剂热合成的方法引入到硼簇合物的合成中并进行同一反应, 得到2个B₁₀H₁₀^2－降解的巢式十一顶双铂九硼烷簇合物: [(PPh₃)₂(μ-PPh₂)Pt₂B₉H₆-3,9,11-(O-i-Pr)₃] (4)和[(PPh₃)₂(μ-PPh₂)Pt₂B₉H₆-3,9-(O-i-Pr)₂-11-Cl] (5). 簇合物4和5都具有Pt₂B₉多面体骨架结构, 2个Pt原子位于敞开的Pt₂B₃面上的相邻位置, 且由一个PPh₂基团桥连, 每个Pt原子还与3个B原子和一个PPh₃基团中的P原子成键. 通过红外光谱、元素分析、X射线单晶衍射对5个簇合物进行了结构表征.     

Spin Relaxation of Electrons in Single InAs Quantum Dots

By using polarization-resolved photoluminescence spectra, we study the electron spin relaxation in single InAs quantum dots （QDs） with the configuration of positively charged excitons X＋ （one electron, two holes）. The spin relaxation rate of the hot electrons increases with the increasing energy of exciting photons. For electrons localized in QDs the spin relaxation is induced by hyperfine interaction with the nuclei. A rapid decrease of polarization degree with increasing temperature suggests that the spin relaxation mechanisms are mainly changed from the hyperfine interaction with nuclei into an electron-hole exchange interaction.     

一维链状超分子化合物[Cu(dafo)_2(H_2O)_2](OPA)_2的合成和晶体结构

用4,5-二氮芴-9-酮(dafo)、邻苯二甲酸和硝酸铜合成了二价铜的一维链状超 分子化合物[Cu(dafo)_2(H_2O)_2]-(OPA)_2(OPA=邻苯二甲酸一价阴离子),其结构 通过单晶X射线衍射法确定。该化合物是单斜晶系,空间群为P2(1)/c。晶胞参数： a = 0.71093(16)nm, b = 1.5724(4)nm, c = 1.5357(3)nm, α=90.000(5) °, β =102.220(4) °,γ=90.000(5) °, V = 1.6778(6)nm~3, Z = 2, F(000) = 814, M_r = 794.17, D_c = 1.527 g/cm~3, μ = 0.727 mm~(-1), R_1 = 0.0406, wR_2 = 0.0930.单晶结构分析表明该化合物具有一维链状结构,该结构是通过氢 键这种弱相互作用形成的。     

射流速度及套管应力的ALE三维仿真分析

聚能射孔是包括炸药爆轰、药型罩压垮形成射流、射流侵彻射孔枪和套管的复杂动态过程,包含能量、质量、速度、变形之间的转化和平衡.本文应用LS-DYNA软件,建立射孔弹-射孔枪-套管三维模型,应用ALE算子分离算法,每一迭代步分为两阶段,先执行网格随物质运动的拉格朗日算法,再执行穿过单元边界的质量、内能和动量的欧拉映射算法,实现爆轰过程、药型罩固流转化、射流高速侵彻套管的大变形和流固耦合仿真,分析爆轰波叠加对能量、密度、射流速度和套管强度影响.一枚射孔弹射孔时,总能量转化为金属射流能量的转换率为13.1%,三枚时为23.1%,爆轰波叠加引起射流转化能量增强.三枚的射流总能量达到133 kJ,超过三个单枚之和75 kJ的77.3%,说明爆轰波重叠使得爆轰产物对射流能量有持续补充作用,对提高孔深有利.射孔弹增加,射流平均能量增大,爆轰产物平均能量减小,但射流和爆轰产物总能量增大,说明弹间的相互作用强烈,爆轰更彻底,对提高孔深有利.三枚较一枚射孔弹射穿套管的时间提前了8μs,最大应力增加了260 MPa,三枚射孔弹时,套管应力值超过材料屈服强度范围较单枚增加了2.5 mm的圆环,爆轰重叠区域中心的套管应力为965 MPa,较单枚时的226 MPa提高了739 MPa,说明爆轰波弹间叠加加重了对套管的伤害.本文实现了射流形成机理、能量和速度转化和射流侵彻过程的流固耦合动态力学分析,搞清了爆轰波叠加对能量、密度、射流速度和套管强度的影响规律.