Phase transformation and crystal growth behavior of 8mol% (SmO1.5, GdO1.5, and YO1.5) stabilized ZrO2 powders

Nanocrystalline powders of ZrO2–8mol%SmO1.5(8SmSZ), ZrO2–8mol%GdO1.5 (8GdSZ), and ZrO2–8mol%YO1.5 (8YSZ) were prepared by a simple reverse-coprecipitation technique. Differential thermal analysis/thermogravimetry (DTA/TG), Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) were used to study the phase transformation and crystal growth behavior. The DTA results showed that the ZrO2 freeze-dried precipitates crystallized at 529, 465, and 467°C in the case of 8SmSZ, 8GdSZ, and 8YSZ, respectively. The XRD and Raman results confirmed the presence of tetragonal ZrO2 when the dried precipitates were calcined in the temperature range from 600 to 1000°C for 2 h. The crystallite size increased with increasing calcination temperature. The activation energies were calculated as 12.39, 12.45, and 16.59 kJ/mol for 8SmSZ, 8GdSZ, and 8YSZ respectively.     

熔盐法制备Bi_(1.5)ZnNb_(1.5)O_7陶瓷

以Bi2O3,ZnO和Nb2O5为原料,KCl为熔盐,采用熔盐法和传统无压烧结工艺合成了单相Bi1.5ZnNb1.5O7陶瓷.XRD和SEM分析表明,在950～1 000℃合成了单相Bi1.5ZnNb1.5O7粉体.研究了不同工艺条件对Bi1.5ZnNb1.5O7陶瓷烧结特性、相组成、微观组织和介电性能的影响.随温度的升高,介电常数先增大后减小,介电损耗变化与之相反.在1 050℃烧结2 h后Bi1.5ZnNb1.5O7陶瓷介电性能最佳:εr≈155(1 MHz),tanδ≈3.1×10-3.     

钠快离子导体Na_(2.5)Zr_(2-x)Ti_xSi_(1.5)P_(1.5)O_(12.0)系统的研究

钠快离子导体Ｎａ_２．５Ｚｒ_２－ｘＴｉ_ｘＳｉ_１．５Ｐ_１．５Ｏ_１２．０系统ｘ＝０－２．０的化合物，由Ｎａ_３ＰＯ_４－ＺｒＯ_２－ＺｒＰ_２Ｏ_７－ＳｉＯ_２－ＴｉＯ_２为反应的起始原料，在９００℃－１２００℃的高温下反应数小时至二十小时制得。系统化合物的相变关系已探明，并测定了有关的单纯相在不同温度下的导电率以及电导激活能。相当于起始组成为Ｎａ_２．５Ｚｒ_１．０Ｔｉ_１．０Ｓｉ_１．５Ｐ_１．５Ｏ_１２．０的单纯相（标为２．５１相）在３００℃时的导电率σ３００＝１．８５×１０－２（Ω·ｃｍ）－１，其电导激活能为２３．６４ｋＪ／ｍｏｌｅ，相当于起始组成为Ｎａ_２．５Ｔｉ_２．０Ｓｉ_１．５Ｐ_１．５Ｏ_１２．０的单纯相（标为２．５２相）在３００℃时的导电率σ３００＝０．４６×１０－２（Ω·ｃｍ）－１，其电导激活能为２８．８９ｋＪ／ｍｏｌｅ．     

Na_(2.5)Hf_(2-x)Ti_xSi_(1.5)P_(1.5)O_(12)系统快离子导体的阻抗谱

系统地研究了Ｎａ２．５Ｈｆ２－ｘＴｉｘＳｉ１．５Ｐ１．５Ｏ１２快离子导体的阻抗谱，采用ＺＲＥＳ３．３程序对实测点进行解释和拟合计算，结果表明该系统呈良好的低温导电性。其中起始组成为Ｎａ２．５Ｈｆ１．８Ｔｉ０．２Ｓｉ１．５Ｏ１２的电导性最好．在４７３Ｋ时，其导电率σ４７３＝１．４７×１０－２（Ω·ｃｍ）－１，电导激活能Ｅａ＝ ２３．８６ｋＪ／ｍｏｌ．     

Structures and Stability of Th(N_6), Pa(N_6), and U(N_6)

The cyclo-N_6 anion is a total nitrogen unit with higher nitrogen content than cyclo-N~-_5. However, the low decomposition barrier of cyclo-N_6 anions hinders its application as a high energy density material(HEDM). Using first-principles calculations, we reveal that the covalent components that enhance the interaction between the cyclo-N_6 anion and the cation can effectively improve the stability of cyclo-N_6 anions. The actinide metals(Th, Pa, U) are selected as suitable cations. Further electronic structure analysis showed that the charge transfer from the actinide metal to cyclo-N_6 anions resulted in a strong covalent bond, which promoted the stability of the cyclo-N_6 anion in the Th(N_6), Pa(N_6), and U(N_6) structure. This discovery is helpful for the rational design and synthesis of new HEDMs.     

Fe-1.5C-1.5Cr-2.0Al超高碳钢的等温组织及力学性能

利用XRD、SEM、TEM、维氏硬度计和拉伸试验机对Fe-1．5C-1．5Cr-2．0Al超高碳钢经300℃等温淬火后的组织及力学性能进行了研究．组织观察与分析表明，等温淬火组织为超细下贝氏体铁素体、残余奥氏体和未溶渗碳体，并随等温时间延长，残余奥氏体体积分数减少，组织细化程度增加．研究发现：等温淬火2—10h，屈服强度为1411—1568MPa，抗拉强度为1632—1744MPa，总延伸率为6．9％～8．5％，硬度为515—532HV。随等温时间的延长，强度和硬度升高，塑性下降．     

11,8(11),15(18),22(25)-四苯氧基金属酞菁的合成与表征

以3-硝基邻苯二腈为前体制备了四苯氧基取代的金属酞菁6～9,对合成化合物进行了质谱、氢核磁、元素分析、红外及紫外可见光谱表征,表征结果证明了它们的分子结构.这些酞菁在有机溶剂中具有很好的溶解性.由于酞菁外围的苯氧基取代基能在一定程度上减弱酞菁的聚合效应,它们不易聚合.产物7和9在极性较小的溶剂(如C6H6和CHCl3)中的紫外吸收光谱与其在极性较大的溶剂(如THF和DMF)中的紫外吸收光谱相比,在740 nm左右多了一个额外的吸收峰,这种现象是不多见的.     

Spectroscopic characterization and stereodynamics of ferrocenylselenoethers Pt(II), Pd(II), Rh(III) complexes

Ferrocenlyselenides (C₅H₅FeC₅H₄SeR, Fe(C₅H₄SeR)₂) and their complexes of metal Pt, Pd, Rh (R=undecenyl, benzyl, phenyl) have been prepared. The spectroscopic characterization has been examined by mass spectrum, XPS, IR and NMR. IR, NMR spectra of C₅H₅Fe C₅H₄Se (CH₂)₉ CH=CH₂PtCl₂ reveal C=C double-bond in Fe(C₅H₄Se (CH₂)₉CH=CH₂)₂ Pt Cl₂ is free because of binding with Pt(II). The results obtained from^H,¹³C and⁷⁷Se NMR indicate that invertomers ofmeso anddl species existence. The ratio ofmeso/dl for BUnSeF Pt is ca 70/30, whereas four and three invertomers for BUnSeF Pt and BBSeFPd have been clearly observed from¹H NMR spectra. Tian Bingshou: born in Feb. 1938, Associate professor     

Cr(Ⅲ),Fe(Ⅲ),Al(Ⅲ),Cu(Ⅱ)草酸配合物热分析研究

目的　研究配合物K3[Fe(C2O4)3]·3H2O,K3[Cr(C2O4)3]·3H2O,K3[Al(C2O4)3]·3H2O和K2[Cu(C2O4)2]·2H2O的热分解过程及机理。方法　采用热分析方法对这4个配合物热分解过程进行研究,用Ozawa Flynn Wall,Friedman,ASTME6983种方法计算出每一步热分解反应的活化能(Ea)和指前因子(lgA)。结果　得出了这4个配合物每一步的热分解反应,并用上述3种方法计算了每一步的活化能和指前因子。结论　这4个配合物第1步热分解都是失去水,但Al,Fe,Cr配合物脱水过程的活化能大小与热解脱水的温度变化趋势基本一致,反映了配合物中水分子结合的难易程度;Cu配合物脱水温度均高于Al,Fe,Cr的配合物。这可能是由于Cu配合物中两个水分子参与配位,而其他配合物中的水为结晶水的缘故。     

Ni_(1.5)Ti_5NbO_(14)光催化剂的结构特征及性质

由高温固相法制备K3Ti5NbO14,并通过离子交换获得Ni1.5Ti5NbO14.采用XRD、UV-vis-DRS、SEM等技术对所制备样品进行表征.通过红外光谱技术考察样品对甲烷气中甲硫醇的吸附性能与光催化氧化性能.结果表明,Ni2+交换K+后,钛铌酸盐仍保持很好的层状结构,其对光谱的吸收由紫外光区域向可见光区域移动,且吸收强度增加.在流动体系中对甲烷气中的甲硫醇具有吸附活性,静态条件下经紫外光辐射对甲硫醇具有光催化氧化活性.     

浅析粤方言的"话"、"讲"、"倾"

粤方言表示言语的常用动词不用“说”、“谈”，而用“话”、“讲”、“倾”。“话”、“讲”、“倾”在粤方言中亦大致有不同的分工。中主要通过具体例证说明粤方言“话”、“讲”、“倾”词义与古汉语调义的联系及其用法上的异同。     

1-苯基-3-甲基-4-三氟乙酰基吡唑酮-(5)与Nd(III),Eu(III),Yb(III)的萃取平衡及络合物的合成和性质

在30℃及0.5mol·L(-1)NaNO_6条件下,测定了Nd(III),Eu(III),Yb((III)与1-苯基-3-甲基-4-三氟乙酰基吡唑酮-(5)(PMTFP)氯仿溶液体系的萃取平衡常数及萃合物的组成。用萃取法合成了Nd(III),Eu(III),Yb(III)与PMTFP的固体络合物,分析了它的组成,并通过它们的红外光谱和紫外光谱,探讨了络合物的结构。     

Eu3+取代Bi1.5MgNb1.5O7陶瓷的结构与介电性能

采用固相法制备Bi1.5-xEuxMgNb1.5O7(x=0、0.1、0.2、0.3、0.4、0.5和0.6)陶瓷。采用X线衍射仪(XRD)、扫描电子显微镜(SEM)和阻抗分析仪分别对陶瓷的相结构、显微结构和介电性能进行表征。结果表明:当Eu3+取代量(x)较小(x≤0.5)时,所有组分的陶瓷样品均保持单一的焦绿石相;当x=0.6时,样品出现少量的EuNbO4杂相。随着Eu3+取代量的增加,陶瓷的介电常数逐渐减小,介电损耗先减小后增大,温度系数显著增大。当x=0.5时,1 MHz下测得的介电常数为96,介电损耗为3.8×10-4,温度系数变成-12×10-6℃-1。因此,通过适当的Eu3+取代可以获得适用于Ⅰ类多层陶瓷电容器性能优异的介质材料。     

锌试剂-吐温80-盐水液-固萃取分离钴、镍和锌

研究了在碱性条件下吐温80与几种盐的分相关系,探讨了盐浓度、碱度对螯合剂和金属离子螯合物萃取率的影响.在最佳分离条件下,实现了Co(II)-Zn(II),Ni(II)-Zn(II)的定量萃取分离.     

“亦”“夜”“腋”字际关系论析

"亦"甲骨文作■、"夜"甲骨文作■,"腋"字在甲骨文未见。从隶变和形声造字法来看,"亦"是"腋"的本字,为指事字,"夜"是从夕亦声的形声字,副词"亦"为"本无其字"的假借字。"腋"字出现在隶变时期,从汉字分化理论来看,表"胳肢窝"义的"腋"字为"从肉亦声"构形的形声字,但隶变后的"月"与"肉"书写形式相混,古文中"夕"与"月"字皆从月象形,故"从肉亦声"构形与"从夕亦声"构形相似。从文字构形避让原则考虑,后来才造出"从月(肉)夜声"的后起字"腋"。     

Ir(Ⅳ)与Mo(Ⅵ), Ga(Ⅲ), Ce(Ⅲ)和V(Ⅴ) 的浮选分离研究

研究表明,在水溶液中, Ir(Ⅳ)与四丁基溴化铵和碘化钾形成不溶于水的三元缔合物[IrI6][TBAB]2,此三元缔合物浮于水相上层形成界面清晰的液-固两相.当溶液中四丁基溴化铵和碘化钾的浓度分别为8.0×10-4 mol/L和6.0×10-3 mol/L时, Ir (Ⅳ)的浮选率达到97.6%.而Mo(Ⅵ),Ga(Ⅲ), Ce(Ⅲ)和V(Ⅴ)离子在该体系中不被浮选,从而实现了Ir(Ⅳ)与这些金属离子的定量分离.对合成水样中Ir(Ⅳ)的分离和测定,结果满意.该方法具有简便、快速等特点,在微量铱的分离和富集分析中有一定的实用价值.     

High-resolution (1.5 A) crystal structure of phospholipase C from Bacillus cereus

Both the phosphatidylinositol-hydrolysing and the phosphatidylcholine-hydrolysing phospholipases C have been implicated in the generation of second messengers in mammalian cells. The phosphatidylcholine-hydrolysing phospholipase C (PLC) from Bacillus cereus, a monomeric protein containing 245 amino-acid residues, is similar to some of the corresponding mammalian proteins. This, together with the fact that the bacterial enzyme can mimic the action of mammalian PLC in causing, for example, enhanced prostaglandin biosynthesis, suggests that B. cereus PLC can be used as a model for the hitherto poorly characterized mammalian PLCs. We report here the three-dimensional structure of B. cereus PLC at 1.5 A resolution. The enzyme is an all-helix protein belonging to a novel structural class and contains, at least in the crystalline state, three Zn2+ in the active site. We also present preliminary results from a study at 1.9 A resolution of the complex between PLC and inorganic phosphate (Pi) which indicate that the substrate binds directly to the metal ions.     

在C_n,C_(nh),C_(nv)(D_n),D_(nh)群上对称结构的动静力分析

应用群表示理论，本文给出了工程中常见的在Ｃｎ，Ｃｎｈ，Ｃｎｖ，Ｄｎｈ这四种 点群上对称结构的统一分析方法。由于引入了超界点、有效子问题等新概念及罚函数 方法，使得该算法可以很客易地推广到其它点群对称结构的分析计算上。相应的力学 软件ＪＩＧＦＥＸ（Ｑ２）已经投入使用，所有计算实践也同样证明该算法无论在计算速 度还是存贮空间上都有成倍的效益．