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  • Author or Editor: Z. Zhong x
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Abstract  

An apparatus to study the battery system has been set up. The thermal effects of charge and discharge of Ni-MH batteries have been studied. The calorimetric measurements indicate that the net heat dissipation during charging is larger than that during discharging. It is observed that the ratio of heat dissipation to charging energy varies with charging capacity, and almost 90 percent of charging energy is lost as heat dissipation near the end of the charging process at 97.7 mA. A jump of thermal curve near the end of discharge due to a secondary electrode reaction has been observed.

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Authors: Z. Zhang, M. Zhong, J. Liu, F. Liu, Z. Wang, F. Zhong and F. Wu

Abstract  

In this work some calorimetric measurements were also carried out on the electrorefining silver by using different current densities with a Calvet type microcalorimeter at room temperature. The ratio (R) of the measured heat (

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m) to the input electric energy (
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in) and the excess heat (
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ex), i.e., difference between
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m and
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in during the electrorefining process, were discussed in terms of general thermodynamics. It was found that the R and
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ex for silver were related with the current density or cell voltage employed in the experiment. The results obtained here also indicate that the heat generation under different conditions, such as different currents or voltages may be caused partially by the irreversibility of the process or by some unknown processes.

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In this study, the peach kernel proteins were extracted and treated with alkaline proteinase to generate peach kernel protein hydrolysate (PKH), which showed angiotensin converting enzyme (ACE) inhibition activity. The hydrolysate was separated into four fractions and their anti-ACE activities were investigated. Our results showed that all PKHs had anti-ACE activity, and the lowest molecular weight fraction PKH4 had the highest ACE inhibitory activity. Lineweaver–Burk plots illustrated that the inhibition types of PKH3 and PKH4 were non-competitive. The Ki of PKH4 was lower than Ki of PKH3; suggesting PKH4 had high affinity to ACE. Amino acid composition analysis showed that the best anti-ACE peptide PKH4 possessed high levels of hydrophobic amino acids, branched-chain amino acids, and aromatic amino acids. In summary, our findings demonstrated that high anti-ACE activity is negatively related to the size of the PKHs and possibly the composition of amino acids, and the PKH4 was the best ACE inhibitor. Further, peach kernel peptides can be developed as a functional food for patients with hypertension.

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Authors: H. Quan, Z. Ge, Z. Li, C. Yin, K. Zhong, Z. Hao, H. Li and F. Ji

Abstract  

The desorption behaviour (desorption temperature and extent of desorption) of HF,HCFC-133a (CF3CH2Cl) and HFC-134a (CF3CH2F) on γ-AlF3 or catalyst supported on γ-AlF3 was studied using an adsorption apparatus and TG, DTA and DSC methods. On the basis of the results a reaction mechanism was proposed for the preparation of HFC-134a. The γ-AlF3 employed for preparing the catalyst was expected to be stable below 550C based on the crystalline phase transition temperature of γ-AlF3.

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Abstract  

Four ethylenediamine-N,N,N′,N′-tetraacetate complexes with Sb(III)-M-Sb(III) polynuclear structure (M=Co(II), La(III), Nd(III), Dy(III)) are synthesized. [Sb24-(EDTA)2Co(H2O)2]·5.15H2O is characterized by single crystal X-ray diffraction. The crystal structure of [Sb24-(EDTA)2Co(H2O)2]·5.15H2O belongs to monoclinic system, space group P21/n, lattice parameters: a=6.9969(2), b=20.8705(4), c=10.8106(2) Å, β=90.031(1)°, V=1578.66(6) Å3, Z=2, M r=1007.76, D c=2.120 g cm−3, F(000)=1001, μ=2.323 mm−1, the final R=0.0235 and wR=0.0629 for 3480 observed reflections (I>2σ(I)). The powder X-ray diffraction patterns of the complexes are also measured. Elemental analyses, FTIR spectra, TG-DSC and DTA of [Sb2(EDTA)2Ln]NO3·nH2O are performed. FTIR spectra reveal that the antimony and other metallic ions were connected through the carboxylate bridges. The thermal analysis can demonstrate the complex formation of the antimony, other metallic ions and EDTA. The possible pyrolysis reactions in the thermal decomposition process of the complexes, the experimental and calculated percentage mass losses are also given.

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Thermal dehydrations

Calcium copper acetate hexahydrate and calcium cadmium acetate hexahydrate

Authors: Y. Masuda, K. Minagawa, W. Morita, Z. Zhong and P. K. Gallagher

Abstract

The behaviour of thermal dehydrations of isomorphous complexes of calcium copper acetate hexahydrate, CaCu(CH3CO2)4·6H2O and calcium cadmium acetate hexahydrate, CaCd(CH3CO2)4· 6H2O was studied by means of thermal analyses and X-ray structural analysis. The enthalpy changes for the dehydration of CaCu(CH3CO2)4·6H2O and CaCd(CH3CO2)4·6H2O were 315±9.7 and 295±8.0 kJ mol−1, respectively. The DSC curves of the dehydrations indicated that the seemingly simple dehydrations are more complex than they appear at first sight. Apparent activation energies for the dehydrations of CaCu(CH3CO2)4·6H2O and CaCd(CH3CO2)4·6H2O were 85.7±7.4 and 87.9±12.5 kJ mol−1, respectively.

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Authors: L. Ji-zhen, F. Xue-zhong, H. Rong-zu, Z. Xiao-dong, Z. Feng-qi and G. Hong-Xu

Abstract  

The thermal behavior of copper(II) 4-nitroimidazolate (CuNI) under static and dynamic states are studied by means of high-pressure DSC (PDSC) and TG with the different heating rates and the combination technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy (thermolysis/RSFTIR). The results show that the apparent activation energy and pre-exponential factor of the major exothermic decomposition reaction of CuNI obtained by Kissinger’s method are 233.2 kJ mol−1 and 1017.95 s−1, respectively. The critical temperature of the thermal explosion and the adiabatic time-to-explosion of CuNI are 601.97 K and 4.4∼4.6 s, respectively. The decomposition of CuNI begins with the split of the C-NO2 and C-H bonds, and the decomposition process of CuNI under dynamic states occurs less readily than those under static states because the dynamic nitrogen removes the strong oxidative decomposition product (NO2). The above-mentioned information on thermal behavior is quite useful for analyzing and evaluating the stability and thermal charge rule of CuNI.

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