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Abstract  

The molar heat capacities of the pure samples of acetone and methanol, and the azeotropic mixture composed of acetone and methanol were measured with an adiabatic calorimeter in the temperature range 78–320 K. The solid–solid and solid–liquid phase transitions of the pure samples and the mixture were determined based on the curve of the heat capacity with respect to temperature. The phase transitions took place at 126.160.68 and 178.961.47 K for the sample of acetone, 157.790.95 and 175.930.95 K for methanol, which were corresponding to the solid–solid and the solid–liquid phase transitions of the acetone and the methanol, respectively. And the phase transitions occurred at 126.580.24, 157.160.42, 175.500.46 and 179.740.89 K corresponding to the solid–solid and the solid–liquid phase transitions of the acetone and the methanol in the mixture, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to standard temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature.

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Abstract  

The phase behaviour and phase stability of lipids are of importance in an understanding of the biological functions of cell membranes. Among a variety of physical techniques employed to study the phase behaviour and structural properties of polar lipids, differential scanning calorimetry and X-ray diffraction have proved to be successful and are the most frequently used methods. Applications involving a combination of the two techniques, particularly when synchrotron radiation is used as the light source of X-ray diffraction, are reviewed in this article.

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Abstract  

The radiochemical method has been used for investigation of the adsorption of radium on eighteen inorganic ion exchangers. The distribution coefficient of radium obtained are as follows: barite 2955, celestite 2420, BaSO4 4350, BaCrO4 5245, Ba3(PO4)2 5775, MnO2·nH2O 1681, La2O3·nH2O 4150, Zerolit S/F 2920, etc.

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Abstract  

2CaO·3B2O3·H2O which has non-linear optical (NLO) property was synthesized under hydrothermal condition and identified by XRD, FTIR and TG as well as by chemical analysis. The molar enthalpy of solution of 2CaO·3B2O3·H2O in HCl·54.572H2O was determined. From a combination of this result with measured enthalpies of solution of H3BO3 in HCl·54.501H2O and of CaO in (HCl+H3BO3) solution, together with the standard molar enthalpies of formation of CaO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(5733.7±5.2) kJ mol−1 of 2CaO·3B2O3·H2O was obtained. Thermodynamic properties of this compound were also calculated by a group contribution method.

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We establish a sharp estimate for some multilinear operator related to Bochner--Riesz operator. As an application, we obtain the weighted norm inequality and L log L type estimate for the multilinear operator.

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A synthetic autopolyploid was developed from diploid Aegilops tauschii, D genome progenitor of common wheat (Triticum aestivum). The tetraploid Ae. tauschii displayed a markedly larger organ size than the diploid donor. Fluorescence in situ hybridization (FISH) and DNA marker analysis revealed that there is no clear variation at either the chromosomal or DNA level between the diploid and tetraploid plants. We analyzed the variation in cytosine methylation patterns between the diploid and tetraploid plants by methylation-sensitive amplified polymorphism (MSAP) and detected 228 and 232 methylated sites in diploid and tetraploid plants, respectively. Statistical comparison indicated that the tetraploid Ae. tauschii genotype displayed no significant difference in polymorphic methylation level compared to the diploid ones. Twenty-two different genomic fragments displaying different methylation behavior during the ploidy conversions were isolated and sequenced. It demonstrated that alterations in the level of methylation have the most profound effects on coding genes. We demonstrated that there are some genes expressions modified by DNA methylation may be correlated with phenotypic alteration after autotetraploidization.

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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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Abstract  

A microcalorimetric technique based on the bacterial heat-output was explored to evaluate the effect of Mn(II) on Bacillus thuringiensis. The power-time curves of the growth metabolism of B. thuringiensis and the effect of Mn(II) on it were studied using an LKB-2277 BioActivity Monitor, ampoules method, at 28C. For evaluation of the results, the maximum peak-heat output power (P max) in the growth phase, the growth rate constants (k), the log phase heat effects (Q log ), and the total heat effect in 23 h (Q T) for B. thuringiensis were determined. Manganese has been regarded as the essential biological trace element. Mn(II) of different concentration have different effects on B. thuringiensis growth metabolism. High concentration (800-1600 μg mL-1) of Mn(II) can promote the growth of B. thuringiensis; low concentration (500-800 μg mL-1) can inhabit its growth.

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Abstract  

A solid complex of rare-earth compounds with alanine, [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)4(H2O)8](ClO4)6 was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid phase transition was found between 99 and 121 K with a peak temperature at 115.78 k. The enthalpy and entropy of the phase transition was determined to be 1.957 Kj mol-1, 16.90 j mol-1 k-1, respectively. Thermal decomposition of the complex was investigated in the temperature range of 40~550C by use of the thermogravimetric and differential thermogravimetric (TG/DTG) analysis techniques. The TG/DTG curves showed that the decomposition started from 120 and ended at 430C, completed in three steps. A possible mechanism of the thermal decomposition was elucidated.

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