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  • Author or Editor: Y. Qiu x
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Abstract  

Deuterium and15N were used as activable tracers for the study of the dissolution of hydrogen and nitrogen in silicon. Silicon was heated or zone-melted in D2-Ar, or heated in15N2-Ar after being covered with Si3 25N4. Depth profiles of D or15N in the resultant silicon samples were measured by the D(3He, p)4He or15N(, n)18F reaction combined with repeated HF–HNO3 etching. These two measurements have proved to be highly reliable and sensitive and to offer useful techniques in the study of trace concentrations of hydrogen and nitrogen in solid matrices.

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Abstract  

The dilution enthalpies of D-mannitol and D-sorbitol in aqueous sodium chloride solution at various concentrations have been determined by isothermal microcalorimetry at 298.15 K. The homogeneous enthalpic interaction coefficients over a quite large range of concentration of aqueous sodium chloride solutions have been calculated according to the excess enthalpy concept. The results show that enthalpic pairwise interaction coefficients (h 2) of D-mannitol and D-sorbitol are positive in aqueous sodium chloride solution and become more positive with increase of the concentration of sodium chloride. The results are interpreted in terms of the different conformations of the two polyols, solute-solute and solute-solvent interactions involved by solvent effects.

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Abstract  

The sensitivity in the determination of deuterium and15N by nuclear reactions was examined for the following reactions: (1)15N(d,n)16O (or p+)+(6.13, 7.11 MeV); (2) D(3He,)4He (13 MeV); and (3)15N(,n)18F. By these activations with suitable etching techniques, sub ppm regions of D and15N have proved to be measurable with their depth profiles. Some fundamental properties of hydrogen and nitrogen in silicon are under investigation using of these activable tracers.

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Abstract  

The principle for the electro-generative simultaneous leaching (EGSL) is applied to simultaneous leaching of pyrite-MnO2 in this paper. A galvanic system for the bio-electro-generative simultaneous leaching (BEGSL) has been set up. The equation of electric quantity vs. time is used to study the effect of produced sulfur on electro-generative efficiency and quantity. It has been shown that the resistance decreased in the presence of Acidithiobacillus thiooxidans (A. thiooxidans) with the increase of electro-generative efficiency. The effects of temperature and grain size on rate of ferrous extraction from pyrite under the conditions of presence and absence of A. thiooxidans were studied, respectively. The changes in the extraction rate of Fe2+ as particle size in presence of A. thiooxidans were more evident than that in the absence, which indicated that the extraction in bio-electro-generative leaching was affected by particle size remarkably. Around the optimum culture temperature for A. thiooxidans, the bigger change in the conversion rate of Fe2+ was depending on temperature. The transferred charge in BEGSL including part of S0 to sulfate group in the presence of (A. thiooxidans) which is called as biologic electric quantity, and the ratio of biologic electric quantity reached to 58.10% in 72 h among the all-transferred charge.

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Abstract  

The low-temperature molar heat capacities of CoPc and CoTMPP were measured by temperature modulated differential scanning calorimetry (TMDSC) over the temperature range from 223 to 413 K for the first time. No phase transition or thermal anomaly was observed in the experimental temperature range for CoPc. However, a structural change was found to be nonreversible for CoTMPP in the temperature range of 368–403 K, which was further validated by the results of IR and XRD. The molar enthalpy ΔH m and entropy ΔS m of phase transition of the CoTMPP were determined to be 3.301 kJ mol−1 and 8.596 J K−1 mol−1, respectively. The thermodynamic parameters of CoPc and CoTMPP such as entropy and enthalpy relative to reference temperature 298.15 K were derived based on the above molar heat capacity data. Moreover, the thermal stability of these two compounds was further investigated through TG measurements. Three steps of mass loss were observed in the TG curve for CoPc and five steps for CoTMPP.

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Abstract  

A dual cell system was used to study the electrogenerative leaching sphalerite-MnO2 under the conditions of presence and absence of Acidithiobacillus ferrooxidans (A. ferrooxidans). The polarization of anode and cathode, and the relationship between the electric quantity (Q) and some factors, such as the dissolved Zn2+, Fe2+, the time in the bio-electro-generating simultaneous leaching (BEGSL) and electro-generating simultaneous leaching (EGSL), were studied. The results show that the dissolved Zn2+ in the presence of A. ferrooxidans is nearly 60% higher than that in the absence of A. ferrooxidans; the electrogenerative quantity in the former is about 134% more than that in the latter. A three-electrode system was applied to study anodic and cathodic self-corrosion current, which was inappreciable compared with the galvanic current between sphalerite and MnO2. The accumulated sulfur on the surface of sulfides produced in the electrogenerative leaching process could be oxidized in the presence of A. ferrooxidans, and the ratio of biological electric quantity reached to 31.72% in 72 h.

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The powdery mildew resistance gene Pm2 is effective in China. Bulked segregant analysis (BSA) was used to search for microsatellite markers linked to Pm2 . Twenty-one microsatellite primer pairs located on chromosome 5DS were screened; three polymorphic loci Xcfd81 -5DS, Xgwm190 -5DS, and Xcfd18 -5DS were linked to Pm2 using an F 2 population from Chinese Spring × C114118 (with Pm2 ) consisting of 814 individuals. The genetic distances between Pm2 and the three markers were: 2.0cM, 34.2cM and 44.2cM, respectively. Microsatellite marker Xcfd81 -5DS could be used in marker assisted selection for Pm2 provided any chosen Pm2 source also carries the relevant marker.

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Abstract  

Nuclear microprobe was used to measure single aerosol particles (SAPs) indoors from Shanghai. Every particle is characterized with its micro-PIXE spectrum, which can be considered as the fingerprint of the SAPs. The pattern recognition technique (PR) was applied to trace the SAPs back to their source. Results of five monitor homes at different locations in Shanghai show that most of the measured indoor aerosol particles are derived from soil dust, cement dust, vehicle exhaust, coal boilers and steel mill dust.

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