钕激光晶体结构,组成和光谱特征研究

本文在考虑交叉弛豫过程的情况下,研究了含Nd~(3+)激光晶体Y_3Al_5O_(12)YAlO_3,LiYF_4和NdP_5O_(14)的辐射跃迁几率、荧光寿命和荧光分支比,解速率方程得到了各能级上粒子数和Nd~(3+)浓度的关系,讨论和比较了四种激光晶体的光谱特征。     

实验室含银废液的回收利用

过去学生在进行摩尔法沉淀滴定实验后,产生的大量AgCl废液,倒入下水道,不仅是很大的浪费,同时也污染了水源。银是国家稀有贵金属之一。硝酸银又是一种紧缺、受控制的化学试剂。如能将上述含银废液回收利用,可为国家节约一笔资金。     

树脂循环复用处理镀金废液的研究

本文对树脂循环复用处理镀金废液进行了系统的研究，研究结果表明：采用NK—SA型树脂及SZ—1、SZ—2型再生剂对Au（Ⅰ）的氰化物体系镀金废液有良好的交换、再生和选择性能，确定了树脂和再生的金盐可以循环复用的最佳工艺。     

实验室废液的回收及效果评价——以“铬废液回收及评价”为例

介绍了一个实验室废液回收及效果评价的实验。进一步巩固学生对晶体制备、化学分析、仪器分析等基本操作的掌握,同时让学生体验废液处理过程中可能出现的一系列条件选择及控制的问题,提升学生分析问题、解决问题的能力,在不断探索中提升学生的学习兴趣,同时能强化学生的人文教育。     

水浸对含钕熔铁氨合成催化剂的影响

已有熔铁氨合成催化剂中添加稀土的报道.我们通过添加稀土得到了几种活性较高的催化剂,经进一步改进制备工艺(水浸处理后),活性又有所提高.本文利用XRD和AES等,对经水浸前后的含稀土催化剂的结构进行了测试,探讨了水浸后活性提高的原因.     

利用含碘废液提取碘的实验研究

“I^- ＋I2平衡常数的测定”实验后,每个同学可剩余含I^-和I2的废液约150 mL,十几组实验后可回收30多升此废液,若随手倒掉,不仅造成碘资源浪费,而且带来环境污染.因此,将此废液回收提取碘再利用,具有明显的经济效益和重要的环保意义.     

实验室废液的回收及效果评价——以“铬废液回收及评价”为例

This paper introduces an experiment about waste liquid recovery and effect evaluation in laboratory. Through this experiment, the basic operations of crystal preparation, chemical analysis and instrumental analysis are further consolidated. At the same time, it allows students to experience a series of possible problems of condition selection and control in the process of waste liquid treatment. We hope to improve the students' ability to analyze and solve problems, enhance their interest in learning, and strengthen their humanistic education.     

铜盐测定实验中铜废液的回收与利用

本文探讨怎样对铜盐测定实验中的铜废液进行回收利用,探讨如何将CuSCN转化为CuO的方法。1问题的提出 碘量法测定铜盐(或铜合金)中的铜含量,是高师化学专业分析化学实验中的一个基础实验。测定     

含钕稀土有机高分子的研究进展

稀土高分子是一类具有许多优异性质和很高应用价值的功能材料 ,其开发和应用前景十分迷人。文章对含钕的稀土有机高分子近几十年来的研究发展情况作了综述     

Zr(OH)4的热分解及ZrO2的相变过程

利用TG-TDG-DTA热分析技术研究了由Zr（OH）4热分解制备ZrO2的脱水过程,并结合X射线粉末衍射技术研究了ZrO2的相变过程．发现在82℃的吸热峰对应Zr（OH）4的脱水,而435℃附近出现的放热峰则为四方ZrO2向单斜ZrO2的晶相转变．采用外推法确定了Zr（OH）4脱水过程遵循三维扩散机理,其函数方程为g（α）=[{1／（1-α）}^1/3-1]^2．以实验获得的动力学参数ln A和E为基础,用最小二乘法对ln A和E进行线性拟合,得到动力学补偿效应表达式为ln A=0．437E-20．69．     

Electroconduction in the Zr|ZrO2| electrolyte system

Electroconduction of anodic oxide films on zirconium in 0.1 M Na₂SO₄ is studied. The films are formed in a galvanostatic regime on single-crystal and polycrystalline iodide-refined zirconium, as well as on electrodes manufactured from a rod obtained by hot extrusion of zirconium iodide melted in an arc furnace and from a plate of iodide-refined zirconium of the I-100 brand. Electrophysical properties of the films are compared on the basis of a model of Frenkel defects, which constitute a system of noninteracting donor centers in the oxide, and a model that describes the formation of a space charge from the donor centers in the oxide (exponential distribution of traps over the films’ bulk). It is shown that experimental current-voltage curves cannot be described by a single model throughout the entire voltage range. At low voltages (<12 V), the Frenkel model is more preferable. In terms of this model, the experimental results can be linearized in the lnI vs. U ^1/2 coordinates. At higher voltages, it is more convenient to describe experimental data within the space-charge model in the I vs. U² or ln(I/U) vs. U coordinates. It is discovered that the technique, which is used for preliminary metallurgical treatment, and the structure of the substrate metal affect parameters of electron conduction in anodic oxide films.     

A Toroidal Zr70 Oxysulfate Cluster and Its Diverse Packing Structures

Herein, we report the discovery of a toroidal inorganic cluster of zirconium(IV) oxysulfate of unprecedented size with the formula Zr₇₀(SO₄)₅₈(O/OH)₁₄₆⋅x(H₂O) (Zr₇₀), which displays different packing of ring units and thus several polymorphic crystal structures. The ring measures over 3 nm across, has an inner cavity of 1 nm and displays a pseudo-10-fold rotational symmetry of Zr₆ octahedra bridged by an additional Zr in the outer rim of the ring. Depending on the co-crystallizing species, the rings form various crystalline phases in which the torus units are connected in extended chain and network structures. One phase, in which the ring units are arranged in layers and form one-dimensional channels, displays high permanent porosity (BET surface area: 241 m² g⁻¹), and thus demonstrates a functional property for potential use in, for example, adsorption or heterogeneous catalysis.     

Catalytic P--H activation by Ti and Zr catalysts

Catalytic dehydrocoupling of phosphines was investigated using the anionic zirconocene trihydride salts [Cp*2Zr(mu-H)3Li]3 (1 a) or [Cp*2Zr(mu-H)3K(thf)4] (1 b), and the metallocycles [CpTi(NPtBu3)(CH2)4] (6) and [Cp*M(NPtBu3)(CH2)4] (M=Ti 20, Zr 21) as catalyst precursors. Dehydrocoupling of primary phosphines RPH2 (R=Ph, C6H2Me3, Cy, C10H7) gave both dehydrocoupled dimers RP(H)P(H)R or cyclic oligophosphines (RP)n (n=4, 5) while reaction of tBu3C6H2PH2 gave the phosphaindoline tBu2(Me2CCH2)C6H2PH 9. Stoichiometric reactions of these catalyst precursors with primary phosphines afforded [Cp*2Zr((PR)2)H][K(thf)4] (R=Ph 2, Cy 3, C6H2Me3 4), [Cp*2Zr((PPh)3)H][K(thf)4] (5), [CpTi(NPtBu3)(PPh)3] (7) and [CpTi(NPtBu3)(mu-PHPh)]2 (8), while reaction of 6 with (C6H2tBu3)PH2 in the presence of PMe3 afforded [CpTi(NPtBu3)(PMe3)(P(C6H2tBu3)] (10). The secondary phosphines Ph2PH and (PhHPCH2)2CH2 also undergo dehydrocoupling affording (Ph2P)2 and (PhPCH2)2CH2. The bisphosphines (CH2PH2)2 and C6H4(PH2)2 are dehydrocoupled to give (PCH2CH2PH)2)(12) and (C6H4P(PH))2 (13) while prolonged reaction of 13 gave (C6H4P2)(8) (14). The analogous bisphosphine Me2C6H4(PH)2 (17) was prepared and dehydrocoupling catalysis afforded (Me2C6H2P(PH))2 (18) and subsequently [(Me2C6H2P2)2(mu-Me2C6H2P2)]2 (19). Stoichiometric reactions with these bisphosphines gave [Cp*2Zr(H)(PH)2C6-H4][Li(thf)4] (22), [CpTi(NPtBu3)(PH)2C6H4]2 (23) and [Cp*Ti(NPtBu3)(PH)2C6H4] (24). Mechanistic implications are discussed.     

含钕聚合物的制备及荧光性质

用复分解的方法制备了辛酸钕[Nd(OCA)_3]和甲基丙烯酸钕[Nd(MAA)_3];将它们分别加入甲基丙烯酸甲酯和甲基丙烯酸的混合体系,聚合后得到交联的[含Nd(MAA)_3]和非交联的[含有Nd(OCA)_3]二种聚合物。研究了上述钕的有机酸盐和二种含钕聚合物的荧光性质。     

ChemInform Abstract: Computational Study of the Zr4+ Tetranuclear Polymer, [Zr4(OH)8(H2O)16]8+

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Basic investigations for laser microanalysis: IV. The dependence on the laser wavelength in laser ablation

The fourth harmonic wavelength at 266 nm as well as the fundamental radiation at 1.06 m of a pulsed Nd: YAG laser has been used for ablation of solid samples. Using different buffer gases and different samples, the ablated masses and plasma temperatures obtained with the two different laser wavelengths are compared. The analytical application of 266-nm laser pulses is studied by the measurement of aluminium and manganese in steel and boraxglass (Na₂B₄O₇) samples.     

Homoleptic organometallic anions of Ti, Zr, Hf, and Nb

Reactions of C(6)H(5)Li and 4-CH(3)C(6)H(4)Li with halides of Ti, Ir, Hf, and Nb lead to the formation of homoleptic organometallic anions of these metals. Owing to their thermal instability and their sensitivity towards H(2) O and O(2) , these compounds are characterized by single-crystal structure determinations at low temperature, whereas other physical data could only be obtained occasionally. Three pentacoordinate complex anions [Ti(C(6)H(5))(5)](-), [Ti(4-CH(3)C(6)H(4))(5)](-), and [Zr(C(6)H(5))(5)](-) have square-pyramidal structures that display only slight deviations from the ideal geometry, in contrast to the already known structures of [Ti(CH(5))(5)](-). The hexacoordinate complex anions [Zr(C(6)H(5))(6)](2-), [Zr(4-CH(3)C(6)H(4))(6)](2-), [Nb(C(6)H(5))(6)](2-), and [Nb(4-CH(3)C(6)H(4))(6)](2-) all have trigonal-prismatic structures, in accord with the known hexamethyl complex dianions. In contrast, the hexacoordinate complex anion [Hf(C(6)H(5))(6)](2)(-) has an octahedral or close to octahedral structure, in contrast to the known trigonal-prismatic structures of [Ta(C(6)H(5))(6)](-) and [Ta(4-CH(3)C(6)H(4))(6) (-). A qualitative explanation for this structural variability is given.     

The Ion-exchange Capacity of Ti and Zr Lamellar Hydrogenphosphates. TG measurements

Thermogravimetric data were used to calculate the number of acidic Brönsted sites in lamellar α-titanium (α-TiP), γ-titanium (γ-TiP), α-zirconium (α-ZrP) and γ-zirconium (γ-ZrP) hydrogenphosphates. The numbers of acidic sites calculated for these lamellar compounds were 7.81, 5.67, 6.33 and 5.56 for α-TiP, γ-TiP, α-ZrP and γ-ZrP, respectively. These values are in good agreement with those found through potentiometric titration. The data obtained prove that thermogravimetric measurements can be used as a reliable analytical tool to follow the ion-exchange capacity of this kind of crystalline lamellar compounds.