The electrical conductivity and anisotropy of the molecular metal: Cs0.82[Pd(S2C2(CN)2)2]·0.5H2O

Results are presented for electrical conductivity measurements in two orthogonal directions in the molecular conductor Cs_0.82[Pd(S₂C₂(CN)₂)₂·0.5H₂O. The conduction band in this complex is believed to be via overlap of π orbitals based on the dithiolate ligands. The electrical conductivity measurements were made using the Montgomery analysis technique which compensates for the geometric shape of the crystal. Electrical conduction was found to be typically 11.0⁻¹ cm⁻¹ along the crystal (a axis) and l.0Ω⁻¹ cm"1 across the crystal (c axis). These measurements therefore give an anisotropy of around 11. The conductivity was recorded between 300 and 90 K.     

Ag−Pd

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Ag−Pd     

[Pd（Ac）2]3的合成工艺之改进

用一种新的合成方法，将钯进行预处理，使其表面活性增大，然后溶入冰醋酸中得到浅棕色结晶，回收率接近１００％，用元素分析，红外光谱，紫外光谱、ＤＴＡ－ＴＧ等对产品进行了表征，结果与文献报道一致。工艺操作简单，回收率稳定，未发现粉红色多聚物，可批量生产。     

Study on syntheses and structures of nine-coordinated mononuclear K[TbⅢ(edta)(H2O)3]·5H2O and binuclear K4[TbⅢ2(Httha)2]·14H2O complexes

The crystal and molecular structures of the K[TbⅢ(edta)(H2O)3]-5H2O (edta = ethylenediaminetetraacetic acid) and K4[TbⅢ2(Httha)2]+14H2O (ttha = triethylenetetraminehexaacetic acid) complexes have been determined by sin-gle-crystal X-ray diffraction analyses. The crystal of the K[TbⅢ(edta)(H2O)3]·5H2O complex belongs to orthorhombic crys-tal system and Fdd2 space group. The crystal data are as follows: a = 1.9373(5) nm, b = 3.5429(10) nm, c = 1.2114(3) nm, V = 8.315(4) nm3, Z= 16, M = 630.35, Dc = 2.014 g cn-3, m = 3.683 mm-1 and F(000) = 5024. The final R and wR values are 0.0224 and 0.0557 for 3189 [I> 2.0o(I)] unique reflections, and 0.0245 and 0.0567 for all 8206 reflections, respectively. The [TbⅢ(edta)(H2O)3]- complex anion has a nine-coordinated pseudo-monocapped square antiprismatic structure in which the nine coordinate atoms, two N and seven O come from one edta ligand and three water molecules. The crystal of the K4[TbⅢ2(Httha)2]·14H2O complex belongs to monoclinic system and P2(1)/n sp     

Nanoscaled grain boundaries and pores,microstructure and mechanical properties of translucent Yb:[LuxY(1−x)O3] ceramics

Translucent ceramics of Yb:[Lu_xY_(1?x)O₃] system doped by ZrO₂ was sintered from nanopowder synthesized by laser evaporation. The relative density of the ceramics was 99.97%, residual pores had sizes from 8 nm to 20 nm, Young modulus was 200 GPa at the applied load of 2000 mN, the microhardness was 12.8 GPa. The grains of ceramics had sizes 1–10 μm, but the thickness of grain boundaries was about 1 nm. The transcrystalline type of the crack propagation was detected in the specially broken ceramics. The results indicated high strength of grain bonds and good perfection of grain boundaries in the studied ceramics but an increased content of pores (higher than 10^?3 vol.%) and stoichiometry deviation (Lu:Y:O = 0.21:0.79:3) from the required one (Lu:Y:O = 0.25:0.75:3).     

Electrical conductivity and thermopower studies on Fex[Pt(C2O2)2]·6H2O (where x ⋍ 0.8)

The electrical conductivity (d.c. and 35 GHz) and thermopower of Fe_x[Pt(C₂O₄)₂]·6H₂O, FeOP, are presented and compared with those of other partially oxidized bis(oxalato)platinate salts of divalent cations. At room temperature FeOP is metallic with a conuctivity of 6 S cm⁻¹ and a thermopower of 15 μV/K. Below room temperature there is a structural transition, which has little influence on transport properties. Below 160 K FeOP is a semiconductor with an activation energy of 55 meV.     

The new salt κ-ET2[Hg(SCN)2I]: crystal structure and physical properties

The structure, resistivity and ESR of a new organic conductor κ-ET₂[Hg(SCN)₂I](ET=bis(ethylenedithio) tetrathiafulvalene) are studied. Its main crystallographic parameters are found to be: M-1213.2, a-38.03(1), b= 11.80(1), c = 8.329(9) Å; γ=98.1(2)°; V-3700(2) ų; space group P2₁Ib; Z = 4. It is shown that the radical cations are packed according to the κ-type in the organic sheets, and the anions form polymerized chains. Two different radical cation layers with different amounts of shortened S···S contacts and distinct interaction between anionic and cationic sheets are found. ESR linewidth is found to be 9-11G (300 K), which is substantially narrower than a typical linewidth for ET-based radical cation salts of the κ-type. Based on temperature dependences of the resistance anisotropy and ESR parameters, we suggest that a structure rearrangement with electron localization may take place around 50 K. The comparison of crystal structure and properties of the title compound with other salts of the family ET₂[Hg(SCN)_3−nX_n], where X=Cl, Br, and n = 1.2, is camed out.     

Raman and FTIR studies of phase transitions in the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Cl

The Raman active CC stretching modes and CH₂ deformation modes and the infrared active CN mode are studied as a function of temperature in κ-(BEDT-TTF)₂Cu(N(CN)₂)Cl under pressure. Effects of the structural and superconducting transitions on these excitations are analyzed. The CH₂ and CN modes are sensitive to the thermal expansion around 80 K and to a possible superlattice transition around 160 K while the CC stretching Raman modes ν₂(A_g) are influenced by the formation of the superconducting state.     

Electron paramagnetic resonance and magnetically modulated microwave absorption experiments on κ-(BEDT—TTF)2Cu[N(CN)2]Cl

Electron paramagnetic resonance (EPR) and magnetically modulated microwave absorption (MMMA) measurements were taken on differently prepared samples of the quasi two-dimensional organic conductor κ-(BEDT—TTF)₂Cu[N(CN)₂]Cl to study the interesting pressure dependent phase transition of this charge-transfer compound. The MMMA results undoubtedly confirm that the substance becomes a superconductor below 12.5 K, if a moderate pressure, e.g. just by embedding the substance in silicon grease during cooling, is applied. At an onset temperature of 25 K an additional microwave absorption is observed, which is about a factor of 100 weaker than the superconducting MMMA signal. We relate this microwave absorption to an antiferromagnetic ordering resulting in weak ferromagnetism by spin-canting occurring at this temperature. The result corresponds to the EPR measurements, where considerable changes in the main EPR parameters, i.e. linewidth, signal amplitude and susceptibility, are observed, giving evidence for an antiferromagnetic ordering below 50 K and a change to weak ferromagnetism below 25 K.     

A mixed κ-(ET)2Cu[N(CN)2]Br0.9I0.1 salt: synthesis,structure and superconductivity

Crystals of κ-(ET)₂Cu[N(CN)₂]Br_0.9I_0.1 (ET = bis(ethylenedithio)tetrathiafulvalene) salt have been prepared, and their structure and conducting properties have been studied. The crystals have been found to undergo a superconducting transition at 3.5 K (T_c) when coated with Apiezon N grease to provide a very low pressure (about 0.3 kbar). With the application of quasihydrostatic pressure, the T_c increases up to 5.9 K at about 3.0 kbar.     

Syntheses and physical properties of quasi-one-dimensional chloro-bridged Ni–Pd mixed-metal MX-chain compounds,Ni1−xPdx(chxn)2Cl3

A series of single crystals of quasi-one-dimensional chloro-bridged Ni–Pd mixed-metal MX-chain compounds, Ni_1−xPd_x(chxn)₂Cl₃ (chxn=1R,2R-diaminocyclohexane) have been obtained by electrochemical oxidation methods. In order to investigate the competition between the electron correlation in the Ni(III) states and the electron–phonon interaction in the Pd(II)–Pd(IV) mixed-valence states in the Ni–Pd mixed-metal compounds, the infrared spectra, resonance Raman spectra, X-ray photoelectron spectra and Auger spectra have been measured. These results show that the Pd(II)–Pd(IV) mixed-valence states are influenced by Ni(III) and gradually approaching to the Pd(III) states with the increase of the Ni(III) components as observed in Br-bridged complexes, Ni_1−xPd_x(chxn)₂Br₃.     

用干冰(粒)喷射清理[英]

介绍了一种环保型金属表面清理技术，干冰（粒）喷射清理。阐述了干冰喷射清理技术的原理、特点和喷射清理设备及其使用情况。     

Preparation and properties of C/C−ZrB2−SiC composites by high-solid-loading slurry impregnation and polymer infiltration and pyrolysis (PIP)

Ultrahigh-temperature ceramics were added to C/C composites to meet their application requirement in a high-temperature oxidizing environment. C/C−ZrB₂−SiC composites were fabricated by high-solid-loading slurry impregnation with polymer infiltration and pyrolysis. The dispersion and rheological behavior of ZrB₂ slurry and the microstructural, mechanical, and ablation properties of the C/C−ZrB₂−SiC composites were investigated. Results indicated that a well-dispersed and low-viscosity ZrB₂ slurry was obtained using 0.40 wt.% polyethyleneimine as a dispersant at pH 5. Ceramics were uniformly distributed in the short-cut fiber layer and needle-punched area. The flexural strength of the C/C−ZrB₂−SiC composites was 309.30 MPa. The composites exhibited satisfactory ablation resistance under the oxyacetylene flame of 2500 °C, and the mass and linear ablation rates were 0.40 mg/s and 0.91 μm/s, respectively. A continuous and compact ZrO₂ layer, which could effectively reduce the diffusion rate of oxygen and protect the composites from being ablated, was formed.     

5,7-二溴[杯(4)芳烃偶氮]氨基喹啉与Pd(Ⅱ)显色反应的研究与应用

合成了新试剂5,7-二溴[杯(4)芳烃偶氮]氨基喹啉(DBCAQ),经红外光谱、元素分析和薄板层析检验其结构.研究了该试剂与Pd(Ⅱ)的显色反应的适宜条件.在pH=5.0的HAc-NaAc缓冲溶液中及非离子表面活性剂吐温-80存在下,试剂与Pd(Ⅱ)生成11的稳定配合物,建立了测定Pd(Ⅱ)的光度法新体系,该体系至少可稳定10h,λmax=680nm,ε=8.26×104L/mol@em,Pd(Ⅱ)浓度在0～35μm/25ml内服从比耳定律.方法已用于钯催化剂中Pd(Ⅱ)的测定,结果与原子吸收法(AAS)结果相符.     

4 K crystallographic and electronic structures of (TMTTF)2X salts (X−: PF6−, AsF6−

The 4 K crystallographic and electronic structures of (TMTTF)₂PF₆ and (TMTTF)₂AsF₆ are presented. The structural investigation was performed by neutron diffraction. Thermal expansion and structural data are compared to those of the Se analogues. The tight-binding band electronic structures are based on calculations of the transfer integrals within the dimer splitting approximation. The results are discussed and compared to the room-temperature values. The trasfer integrals of the two salts, which are very similar at 300 K, tend to differ markedly at low temperature. The observed differences in the transfer integrals are related to the changes of the orientation of two neighbouring organic chains. The variations of the electronic parameters appear to depend on the anion.     

Zn(H2PO4)2-N[CH2CH2OPO(OH)2]3对碳钢的协同效应与缓蚀机理研究

采用失重法、表面观察法、极化曲线法、氩离子刻蚀法和ＸＰＳ分析法研究Ｚｎ（Ｈ２ＰＯ４）２－Ｎ「ＣＨ２ＣＨ２ＯＰＯ（ＯＨ）２」３在海水中对碳钢的协同效应与缓蚀机理。结果发现：５０％Ｚｎ（Ｈ２ＰＯ４）２＋５０＾Ｎ「（ＣＨ２ＣＨ２ＯＰＯ（ＯＨ）２」３（ＸＭ－３０３在海水中对碳钢具有明显的协同缓蚀效应。５０％Ｚｎ（Ｈ２ＰＯ４）２＋５０％Ｎ「ＣＨ２ＣＨ２ＯＰＯ（ＯＨ）２」３（ＸＭ－３０３）主要为阴极抑制型缓蚀     

Kinetics of Thermal Decomposition for Complex [Zn(C_(16)H_(18)FN_3O_3)_2(NO_3)_2]·2H_2O

1 ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｒｅｃｅｎｔｙｅａｒｓ ,ｔｈｅｉｎｔｅｒａｃｔｉｏｎｂｅｔｗｅｅｎｎｏｒｆｌｏｘａｃｉｎａｎｄｃｅｒｔａｉｎｍｅｔａｌｌｉｃｉｏｎｓｈａｓｂｅｅｎｖａｌｕｅｄｗｉｄｅｌｙ[1～ 4].Ｂｕｔｔｈｅｎｏｎ ｉｓｏｔｈｅｒｍａｌｋｉｎｅｔｉｃｓｏｆ[Ｚｎ(ＮＦＡ) 2 (ＮＯ3) 2 ]·2Ｈ2 Ｏｔｈｅｒｍａｌｄｅｃｏｍ ｐｏｓｉｔｉｏｎｈａｓｒａｒｅｌｙｂｅｅｎｓｔｕｄｉｅｄ .Ｉｎｔｈｉｓｐａｐｅｒ ,ｗｅｄｉｓｃｕｓｓｅｄｉｔｓｔｈｅｒｍａｌｄｅｃｏｍｐｏｓｉ ｔｉｏｎｂｅｈａｖｉｏｒｂｙ…     

Synthesis and Structural Determination of Nine-Coordinate K[Gd~Ⅲ(edta)(H_2O)_3]·5H_2O

1 IntroductionMagnetic Resonance Imaging (MRI) ap-peared in l980's. It has gradually become animPortant member in the diagnosis imagingtechnology fieId. Generally, in order to furtherraise the diagnosis quality of MRI, this tech-no1ogy needs to be imPoved and perfectedthrough two respects, i.e., the imProvement ofinstrument design and the aPplication of contra-st agents containing paramagnetic coInPounds.In fact, these paramagnetic comPounds appar-ently shorten relaxation time, increase…