5－（2－硫甲基－4－甲基－5－嘧啶基）－2，4－戊二炔－1－醇α甲基丙烯酸酯非线性光学材料

聚二乙炔（ＰＤＡ）类化合物在超快全光开关、逻辑门和远距离通讯系统的多路传输等方面有着潜在的应用前景。但并不是所有的ＰＤＡ都能用于这些方面，它的选择应当考虑聚合性能、链密度、共轭度、溶解性、热稳定性及可加工性等多方面的因素。本文首次报道了５－（２－硫甲基－４－甲基－５－嘧啶基）－２，４－戊二炔－１－醇甲基丙烯酸酯（ＰＤＭＡ）的合成，该物质极易聚合、链密度高、聚合物可溶、单体热稳定性好，在许多方面可与当前最好的化合物ＰＴＳ及ｐｏｌｙ－４ＢＣＭＵ相媲美。     

Crystal Structure of Ni5P2

It is shown by x-ray diffraction, energy-dispersive x-ray spectrometry, and electron probe microanalysis that, at 800°C, the Ni–P system contains four phosphides in the composition range 25–33 at % P: Ni₃P, Ni₅P₂, Ni₁₂P₅, and Ni₂P. The structure of Ni₅P₂ is determined by single-crystal x-ray diffraction: sp. gr. P3¯c1, new structure type, a = 0.6613(3) nm, c = 1.2311(6) nm, 347 independent hklreflections with F _hkl > 4(F _hkl), R _F = 0.0346. The key structural features of Ni₅P₂ are discussed.     

PbBr2-PbF2-P2O5玻璃的结构研究

采用红外光谱(IR)和X射线光电子能谱(XPS)等方法研究了PbBr₂-PbF₂-P₂O₅系铅卤磷酸盐玻璃的结构.结果表明,Pb²⁺离子在玻璃中起着网络修饰阳离子和网络形成体的双重作用.当P₂O₅含量为60mol％时,Pb²⁺离子主要是作为网络修饰体;当P₂O₅含量降低到50mol％时,一部分Pb²⁺离子能够进入玻璃网络形成[PbO₄]四面体或P-O-Pb键.Br^-和F^-离子达到一定浓度时就会进入玻璃网络,形成[PO_4-nX_n](X=Br或F,n=0-4)四面体使磷酸盐链长变短.玻璃中P₂O₅的含量不变时P-O-P键的比例也基本保持不变;当P₂O₅的含量降低时,P-O-P键和P-O^-键的含量都减少,P-O-Pb键的含量则明显增加.     

Li_2O-B_2O_3-V_2O_5系玻璃的结构

本文用 Raman 光谱和声学方法研究了 Li_2O-B_2O_3-V_2O_5系玻璃的结构。结果表明:V_2O_5主要以 LiVO_3即[VO_3]_n~(?)形式存在,而 B_2O_3则与 Li_2O 结合生成一系列硼酸盐。     

Recovery of 1 2 5Sb from Neutron-Irradiated 1 2 4Sn

Recovery of ^{1 2 5}Sb from metallic tin (96% enrichment with ^{1 2 4}Sn) irradiated in a nuclear reactor (specific activity 5 mCi g^{- 1}) was studied. Irradiated tin was dissolved in concentrated HCl with addition of H₂O₂ or Br₂; dissolution was monitored with ^{1 1 9 m} Sn tracer. The separation of ^{1 2 5}Sb and tin was studied using strongly basic (Dowex-50, AV-17), moderately basic (AN-2FN), and weakly basic (AN-31) anion exchangers with HCl, HCl + HBr, and HNO₃ eluents. In the case of strongly basic anion exchangers, the separation coefficients of ^{1 2 5}Sb from tin reached 10⁴-10⁵ in a single cycle. From for AN-31 weakly basic anion exchanger, tin was almost completely removed with 0.8 M HCl; the yields of tin and ^{1 2 5}Sb were 99 and 98%, and the content of ^{1 2 5}Sb in tin was no more than 0.1% of the initial activity.     

Ge掺杂对TiO2-Nb2O5-CaCO3压敏陶瓷结构及性能的影响

TiO₂ 压敏电阻是一种典型的非线性电流-电压电子器件, 本文研究了Ge掺杂对TiO₂-Nb₂O₅-CaCO₃压敏陶瓷的非线性系数α和压敏电压E_B的影响。采用传统的球磨-成型-烧结方法成功制备Ge掺杂TiO₂-Nb₂O₅-CaCO₃压敏陶瓷, 用压敏直流参数仪测试样品的非线性系数α、压敏电压E_B和漏电流J_L等电学性质, 并根据相关公式计算样品平均势垒高度。XRD、XPS、SEM和STEM分析表明, Ge掺杂显著改变TiO₂-Nb₂O₅ -CaCO₃压敏陶瓷微结构, 提高非线性系数α和减小压敏电压E_B。当施主Nb₂O₅和受主CaCO₃掺杂浓度分别为0.5mol%时, 掺杂1.0mol% Ge的压敏陶瓷获得了最高的非线性系数和较低的压敏电压(α=10.6, E_B=8.7 V/mm), 明显优于不掺杂Ge的TiO₂-Nb₂O₅-CaCO₃压敏陶瓷。此外, Ge熔点较低, 作为烧结助剂可以降低陶瓷的烧结温度, TiO₂-Nb₂O₅-CaCO₃-Ge压敏陶瓷最佳烧结温度是1300℃。     

Structure of Second Phase Particles in As-cast Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd Alloy

The microstructure of the Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd (Ti-55) alloy containing second phase particles was studied. The second phase particles are 1~15 μm in size and most of them are distributed at the grain boundaries in the form of ellipsoid with a few short needle-like and blocky phases. It consists of either dark or bright amorphous "matrix", and some small spots dispersed within the "matrix", which match SnO (orthorhombic, a=0.500 nm, b=0.572 nm, c=1.12 nin).     

Nb_2O_5对碲铅铋铌系玻璃结构和性能的影响

采用熔融法制备不同Nb2O5含量的TeO2-PbO-Bi2O3-Nb2O5系玻璃粉,研究了Nb2O5的加入量对TeO2-PbO-Bi2O3-Nb2O5系玻璃热膨胀系数、软化温度和热稳定性的影响。利用傅里叶变换红外光谱仪检测玻璃粉的结构,通过热机械分析仪和综合热分析分别测试玻璃的膨胀系数和析晶温度,采用场发射扫描电镜观察太阳能电池Ag/Si接触界面。结果表明,随着Nb2O5含量的增加,玻璃的热膨胀系数和软化温度逐渐降低,玻璃化温度和析晶温度逐渐升高,玻璃的热稳定性逐渐增强。添加Nb2O5的玻璃粉所对应的太阳能电池正面电极中,Ag/Si接触界面存在大量的纳米银粒子,这将更有利于晶硅太阳能电池的光电子传导。     

渗铝钢在Na2SO4V2O5熔盐体系中的热腐蚀行为

以往对渗铝钢耐热腐蚀性能的研究缺乏深度,为解决实际问题,在750 ℃模拟灰垢熔盐体系中,研究了加热炉辐射室炉管常用材料20G钢、20G渗铝钢、Cr5Mo钢、Cr5Mo渗铝钢的腐蚀行为.结果表明:20G钢、Cr5Mo钢、20G渗铝钢和Cr5Mo渗铝钢抗熔灰腐蚀能力依次增强;渗铝可以大大提高合金的耐熔灰腐蚀性能,在纯空气中氧化,其耐蚀性能也十分优异;20G渗铝钢在熔灰腐蚀时元素Al优先氧化并不十分明显,Cr5Mo渗铝钢在熔灰腐蚀时元素Al优先氧化;按照电化学模型,在熔灰腐蚀中V-2O-5不但会溶解金属氧化物的保护层,而且还参与阴极过程,循环反应,加速了金属的氧化腐蚀.     

Hyperfine Structure of the 6P1/2

Abstract

The hyperfine splitting of the 6P_1/2–6P_3/2 fine structure transition in ²⁰⁷Pb⁺ ions at 710 nm has been measured by c.w. laser excitation and subsequent observation of the weak fluorescence radiation at the same wavelength. The ions were confined in an rf quadrupole trap and buffer gas cooled by collisions with He atoms at 10^?5 mbar pressure. From the observed level splitting and the simultaneously recorded transmision of a Fabry-Perot etalon we determined the hyperfine splitting constants A(6P_1/2) = 13·001(48) GHz and A(6P_3/2) = 0·589(23) GHz. From a small impurity of ²⁰⁸Pb of our isotopically enriched sample we determined the isotope shift of the transitions to Δv(207–208) = 252(40) MHz.     

Structure and electrical characteristics of Ce4+-doped Ba2In2O5

The In-site of Ba₂In₂O₅ with Brownmillerite structure was partially substituted for Ce⁴⁺ ions in order to examine the doping effect on the order-disorder transition. Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.1, 0.2, 0.3, 0.5, 1.0, and 1.5) were prepared by solid state reaction. X-Ray diffraction analyses of these powder samples demonstrated that Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.1 and 0.2) possesses Brownmillerite structure. With increasing content of Ce⁴⁺ ion the crystal system of Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.3, 0.5, and 1.0) changed to cubic perovskite structure above the order-disorder transition temperature of Ba₂In₂O₅. Arrhenius plots of the electrical conductivities of Ba₂In_{2 – x} Ce _x O_{5 + x/2} (x = 0.2, 0.3, and 1.0) exhibited no discontinuity. These compounds had high transference numbers of oxide ion above 973 k.     

SnO—BaO—P2O5系统无铅封接玻璃的结构与性质

以SnO—BaO—P2O5三元系统玻璃为研究对象,利用差示量热扫描分析仪、热膨胀仪、拉曼光谱仪,分析了玻璃的结构以及玻璃转变温度和热膨胀系数与玻璃组成的关系．获得了该体系玻璃的形成区域,测得该系统的玻璃转变温度为260～360℃和热膨胀系数为12～14×10^-6℃．研究发现,当P2O5=45mol％不变时,玻璃转变温度随着SnO含量的增加而降低;当BaO=10mol％不变时,玻璃转变温度随着SnO含量的增加先降低后升高．研究表明,该体系玻璃可以作为低温环保封接玻璃潜在的基质材料．     

SnO-BaO-P2O5系统无铅封接

以SnO-BaO-P2O5三元系统玻璃为研究对象,利用差示量热扫描分析仪、热膨胀仪、拉曼光谱仪,分析了玻璃的结构以及玻璃转变温度和热膨胀系数与玻璃组成的关系.获得了该体系玻璃的形成区域,测得该系统的玻璃转变温度为260～360 ℃和热膨胀系数为12～14×10-6 ℃-1.研究发现,当P2O5=45 mol%不变时,玻璃转变温度随着SnO含量的增加而降低;当BaO=10 mol%不变时,玻璃转变温度随着SnO含量的增加先降低后升高.研究表明,该体系玻璃可以作为低温环保封接玻璃潜在的基质材料.     

TiO2—Nb2O5复合氧化物氧敏响应特性及结构研究

将ＴｉＯ２和Ｎｂ２Ｏ５氧化物氧敏材料复合，研究氧敏响应特性及其与环境温度，气流转换频率的关系，并指出采样方法对响应时间的影响。在无贵金属催化条件下，烧结型复合氧敏材料的响应时间约为６０ｍｓ。对材料的结构与响应机理进行了分析与初步探讨。     

溶胶凝胶-熔盐法制备Cd1-xCoxFe2O4及磁性研究

通过溶胶凝胶-熔盐法以NaCl为熔盐制备了掺杂(Co2+的Cd1-xCOxFe2O4(x=0～0.5)尖晶石型铁氧体.利用XRD、SEM和VSM等手段对样品进行了结构、形貌和磁性表征,并详细讨论了Co2+对Co1-x-CdxFe2O4(x=0～0.5)铁氧体结构和磁性的影响.结果表明:在研究范围内掺杂后仍然能得到单相尖晶石结构铁氧体;样品均为正八面体;比饱和磁化强度随x的增大而增加.     

Li_2O-B_2O_3-V_2O_5 系玻璃的形成、结构与离子导电性

本工作确定了 Li_2O-B_2O_3-V_2O_5系玻璃的形成区,测量了玻璃的电导率、光吸收、ESR 和 Raman 谱、密度及超声速。结果表明:所研究玻璃的电导主要是离子性的;V_2O_5与 B_2O_3对于形成 Li~+导电玻璃是有利的;玻璃中主要结构单元为[VO_3]_n~(n-)和一些硼酸盐基团。得到了300℃时电导率为2.5×10~(-3)(Ω·cm)~(-1)的玻璃。     

A Highly Efficient and Stable Blue-Emitting Cs5Cu3Cl6I2 with a 1D Chain Structure

In the field of photonics, alkali copper(I) halides attract considerable attention as lead-free emitters. The intrinsic quantum confinement effects originating from low-dimensional electronic structure lead to high photoluminescence quantum yields (PLQYs). Among them, Cs₃Cu₂I₅ is the most promising candidate, satisfying both high PLQY and air stability. In this study, a strategy to explore a new material meeting these requirements through the use of the mixed-anions of I⁻ and Cl⁻ is proposed. The expectation is maintained that the large difference in ionic radii between them likely results in the formation of a novel compound. Consequently, Cs₅Cu₃Cl₆I₂ with a 1D zigzag chain structure is discovered. This material exhibits blue emission (≈462 nm) with a near-unity quantum yield of 95%. An electronic structure calculation reveals that the localized nature of the valence band maximum is crucial in obtaining efficient self-trapped exciton emission. Moreover, the iodine-bridged 1D connectivity significantly enhances the chemical stability of Cs₅Cu₃Cl₆I₂, compared with the pure chloride phase. The present findings provide a new perspective for developing air-stable alkali copper(I) halides with highly efficient luminescence.     

K_2NbOF_5－MF_3系玻璃的结构及电性质

研制了Ｋ＿２ＮｂＯＦ＿５－ＭＦ＿３（Ｍ＝Ａｌ、Ｇａ）新体系氟化物玻璃，测定了玻璃的特征温度、Ｒａｍａｎ光谱和电导率，玻璃中Ｎｂ￣（５＋）、Ａｌ￣（３＋）、Ｇａ￣（５＋）分别以ＮｂＯＦ、ＡＩＦ、ＧａＦ八面体形式存在，玻璃的电导率随ＡｌＦ＿３含量的增加而增加，ＡｌＦ＿３含量达到３０ｍｏｌ％时，Ａｌ￣（３＋）除ＡＩＦ八面体外，还有ＡｌＦ四面体结构出现，同时电导率降低，Ｆ￣－阴离子是主要的导电离子，７５Ｋ＿２ＮｂＯＦ＿５·２５ＡｌＦ＿３玻璃的电导率在１９６℃时，σ＝１．０２×１０￣（－２）Ｓ·ｃｍ￣（－１）。     

Structure and morphology of TiB2 duplex coatings deposited over X40 CrMoV 5-1-1 steel by DC magnetron sputtering

The deposition of titanium diboride (TiB₂) films over tool steel substrates (AISI H13 premium/EN X40 CrMoV 5-1-1) is being investigated due to its excellent corrosion resistance and chemical stability against liquid aluminium. The use of nitrided steels as substrates for TiB₂ deposition may contribute to increase its adhesion and the overall steel resistance in applications such as forging, extrusion and die casting of aluminium. Duplex coatings were obtained by the PVD deposition of TiB₂ films over heat treated and nitrided steel using non-reactive DC magnetron sputtering from a TiB₂ target, varying the substrate bias voltage. Well structured and crystalline TiB₂ films were obtained for the selected deposition conditions, the best crystalline coatings being obtained for the positively biased substrates. Selected films produced over die-casting pins at a bias voltage of +50 V were tested for resistance to liquid aluminium soldering by immersion tests, and compared with the nitrided steel. The duplex TiB₂ coating has a much larger chemical resistance to attack by molten aluminium alloy than the just nitrided steel. Where there is soldering, steel is rapidly attacked and a complex Al-Fe-Si intermetallic forms.     

Structure and growth peculiarities of Tl1bSe1bTlInSe2

The crystal structure and growth peculiarities of isomorphic pairs like Tl1bSe1bTlInSe₂ are investigated in this paper. The structure of TlInSe₂ in projection and in polyhedrons, photographs of grown crystals with different geometrical configurations, as well as microphotographs of the boundary of epitaxially grown Tl1bSe1bTlInSe₂ heterojunctions are represented.