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41.
Dr. Dingfeng Yang Junzhu Yang Xuejun Quan Bin Zhang Guoyu Wang Xu Lu Xiaoyuan Zhou 《Chemphyschem》2021,22(24):2579-2584
Understanding the correlation between crystal structure and thermal conductivity in semiconductors is very important for designing heat-transport-related devices, such as high-performance thermoelectric materials and heat dissipation in micro-nano-scale devices. In this work, the lattice thermal conductivity ( ) of the cage-like compounds Cu3VSe4 and Cu3NbSe4 was investigated by experimental measurements and first-principles calculations. The experimental of Cu3NbSe4 is approximately 25 % lower than that of Cu3VSe4 at 300 K. The relevant important physical parameters, including the sound velocity, heat capacity, weighted phonon phase space (W), and third-order force constants along with atomic mass were theoretically analyzed. It is found that W is the dominant parameter in determining the , and the other factors only play a minor role. The physical origin is the relatively “soft” lattice of Cu3NbSe4 with heavier atomic mass. This research provides deep insight into the correlation between the thermal conductivity and crystal structure and paves the way for discovering high-performance thermal management device and thermoelectric materials with intrinsically low . 相似文献
42.
Eu1—xTbxBa2Cu3O7—δ中Tb离子价态的研究 总被引:1,自引:0,他引:1
研究了BaTbO_3、Tb_4O_7、TbFeO_3的Tb_(4d)XPS谱,找到了表征Tb~(3+)、Tb~(4+)的特征峰,得出的高、低结合能峰强之比与Tb~(4+)/Tb含量间的依赖关系,可用于确定Eu_(1-x)Tb_xBa_2Cu_3O_(7-δ)中“123”相的Tb离子混合价态,用常压高温烧结法,未能获得纯“123”单相,也不易获得纯利Tb~(3+)价态样品.在Eu_(1-x)Tb_xBa_2Cu_3O_(7-δ)中的Tb以Tb~(3+)、Tb~(4+)混合价态存在;当x=0.3时,Tb~(4+)/Tb=0.61.引入Tb~(4+)后“123”主相Cu(2)-O(2)平面上的O_(2p)空穴数降低,这是Tb~(4+)破坏超导电性的一种可能原因。 相似文献
43.
含间苯基聚芳醚酮的合成与性能研究 总被引:3,自引:0,他引:3
含间苯基聚芳醚酮的合成与性能研究林权,张万金,吴忠文,尹玖梅(吉林大学化学系,长春,130021)(中国科学院长春应用化学研究所)关键词聚芳醚酮,间苯基,熔点,结晶度聚芳醚酮作为一类耐高温特种工程塑料,由于具有优异的热、电、机械性能,已被广泛应用于电... 相似文献
44.
The refolding of the reduced-denatured insulin from bovine pancreas was investigated with the size exclusion chromatography (SEC). It was shown that the reduced-denatured insulin originally denatured with 7.0 mol L?1 guanidine hydrochloride (GuHCI) or 8.0 mol L?1 urea could not be refolded with a non-oxidized mobile phase. Although the oxidized and reduced glutathione (GSSG and GSH) were employed in the oxidized mobile phase, the reduced-denatured insulin still could not be renatured. However, in the presence of 2.0 mol Lt-1 urea in the oxidized mobile phase employed, the reduced-denatured insulin can be refolded with SEC, and the aggregation of denatured insulin can be diminished by urea. In addition, the disulfide exchange of reduced-denatured insulin also can be accelerated with GSSG/GSH in the oxidized mobile phase. The three disulfide bridges of insulin were formed correctly and the reduced-unfolded insulin can be renatured completely. The results were further tested with reversed-phase liquid chromatography (RPLC) and hydrophobic interaction chromatography (HIC). 相似文献
45.
A procedure for the Raman spectra calculation of vitreous and molten silicates was presented in this paper. It includes molecular dynamics MD simulation for the generation of equilibrium configurations, Wilson's GF matrix method for the calculations of eigenfrequencies and corresponding vectors, electro-optical parameters method (EOPM) for the Raman intensity calculations, and the bond polarizability model (BPM) for the determination of polarizability and polarizability derivative. One of the most important characteristics of this procedure is the achievement of the partial Raman spectra of five tetrahedral units, as well as the total spectral envelope. In this paper, the calculation was carried out for the vitreous and molten calcium silicates with different compositions and at various temperatures. It is worthwhile to note that the calculation is based on statistical configurations distribution in the space and so it is not needed to artificially adjust the full width at half maximum (FWHM) of spectra. It was also tested through the good agreement of the calculated spectra with the experimental, including some regularity of spectral properties. According to the calculation, the symmetrical stretching of whole tetrahedral units, to which the stretching of Si-O(nb) bond gives the main contribution to intensity, is proven to be the dominance in the high-frequency range (800-1200 cm(-1)) and the symmetrical bending of Si-O(b)-Si, to which the stretching of Si-O(b) bond exhibits the main contribution, is the dominance in the medium-frequency range (400-700 cm(-1)). As the first theoretical results, the Raman scattering coefficient of each Q(i) was found little change along with the variation of composition and temperature. 相似文献
46.
Study on the Phase Diagram of CsCl-CeCl3-HCl(11%)-H2O System and the Properties of the Compounds 总被引:2,自引:0,他引:2
The equilibrium solubility of CsCl-CeCl3-HCl(11%)-H2O qua-ternary system at 25℃ has been determined by the physicchemical analysis method ,and the phase diagram was plotted, Two new double salts 3CsCl.CeCl3.3H2O and CsCl.CeCl3.4H2O obtained from the complicated system were identified and characterized by XRD,TG-DTA ,DSC,UV and fluorescence spectroscopy, Studies on the fluorescence excitation and emission show that 3CsCl.CeCl3.3H2O and CsCl.CeCl3.4H2O have upconversion luminescence of infrared-visible range,and the upconversion emission intensity increases with the increase of ratio of CeCl3 in CsCl. 相似文献
47.
Shihui Si Fenglian Ren Wen Cheng Shouzhuo Yao 《Analytical and bioanalytical chemistry》1997,357(8):1101-1105
To obtain new coatings for the preparation of piezoelectric immunosensors, the anodic polymerization of o-aminophenol (oAP),
o-phenylenediamine (oPD) and m-phenylenediamine (mPD) onto a gold-plated crystal has been studied. The possibility of immobilizing
an antibody (anti-S. paratyphi A) onto the crystal via the electropolymerized films was investigated. The poly-mPD film gave
the best results for immobilizing the antibody. With antibodies crosslinked on the poly-mPD film, a piezoelectric immuno-assay
for the detection of S. paratyphi A was proposed. The shift (ΔF=F20s−F400s, Hz) between the frequency at 20 s after the addition of sample (F20s), and that of 400 s (F400s) was used to construct a calibration graph, and shortening of the assay time was achieved. The S. paratyphi A concentration
in the range of 105–109 cells/ml can be measured by this method.
Received: 9 May 1996/Revised: 6 September 1996/Accepted: 19 September 1996 相似文献
48.
Feng Liu Si Guo Yuan Xiao Li Wang A.E Polikarpov A.A. Shunkevich 《中国化学快报》2007,18(5):588-590
A fibrous sorbent possessing abundant micropore structure was firstly prepared via post-crosslinking reaction on the PP-ST-DVB original fiber. Its micromorphology and sorptive properties were investigated, and the results demonstrated that the novel fibrous hypererosslinked sorbent has narrow pore-size distribution, small average porous radius (1.90 nm), high specific surface area (362.31 m^2/g), and fine sorptive properties for small organic molecules. 相似文献
49.
Ping ZHENG Wei Lin SUN Zhi Quan SHEN 《中国化学快报》2005,16(10):1413-1416
N-2-Thiazolylacrylamide (NTA) was polymerized by a radical route to obtain the polymer in good yield. The polymer with a pendent heterocyclic group is soluble in common organic solvents, which allow to prepare the corresponding metal complexes with higher loads easily. FTIR, ^1H NMR, elemental analysis, and energy-dispersive X-Ray spectroscopy (EDX) were applied to characterize these materials. The magnetic behavior of Fe(Ⅱ) and Nd(Ⅲ) complexes of poly(N-2-thiazolylacrylamide) was examined by a PPMS-9T magnetometer, exhibiting the characteristics of a soft ferromagnet. It is found that the Nd(Ⅲ) complex has an extremely high relative saturation magnetization of 35 emu/g. 相似文献
50.
Jiang Ke QIN Xian Zhang BU Yu Fang WANG Zhi Yun DU Xing Yuan WANG Zhi Shu HUANG Lin MA Lin Kun AN Lian Quan GU 《中国化学快报》2005,16(11):1451-1454
The reactions of tanshinone IIA with aromatic aldehydes have been investigated and several 2, T-(substituted arylmethylene) bis (1,6,6-trimethyl-6,7,8,9-tetrahydrophenanthro[1,2-b]- furan- 10, 11-dione) derivatives were obtained, 相似文献