In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combusti...In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.展开更多
Water-soluble polysaccharide was isolated from grapefruit with the method of water-dissolving and ethanol-precipitating. By single factor test and orthogonal experimental method, the extraction conditions of the water...Water-soluble polysaccharide was isolated from grapefruit with the method of water-dissolving and ethanol-precipitating. By single factor test and orthogonal experimental method, the extraction conditions of the water-soluble polysaccharide were investigated, which contained liquid-solid ratio, temperature, time and pH. The results showed that pH was the most important factor of polysaccharide extraction, followed by temperature. The optimized extraction technology conditions were obtained. The liquid-solid ratio was 1:40, temperature was 90?C, time was 2.0 h, and pH was 2. The highest extraction rate of crude polysaccharide was 8.30%.展开更多
[Objectives] The fermentation conditions of Candida tropicalis 1798-pxa1 were optimized to further improve its yield of long-chain dibasic acids. [Methods] The strains used in the study were C. tropicalis 1798, C. tro...[Objectives] The fermentation conditions of Candida tropicalis 1798-pxa1 were optimized to further improve its yield of long-chain dibasic acids. [Methods] The strains used in the study were C. tropicalis 1798, C. tropicalis 1798-pxa1 and C. tropicalis 1798-pxa1 p2. First, through single factor experiments, the activated three fungi were cultured in different carbon sources, and the absorbance was measured every 2 h. The growth curve was drawn by software, and finally the most suitable substance for the substrate was selected, i.e., dodecane. Then, the composition of the fermentation medium and the fermentation process parameters were determined through the PB experiment of the single-deletion C. tropicalis 1798-pxa1. [Results] The experiment determined the important components affecting the synthesis of long-chain dibasic acids, namely(NH_4)_2SO_4, NaCl and dodecane. After optimization of the culture conditions, the yield of long-chain dibasic acids of C. tropicalis 1798-pxa1 increased from 5.6 to 10.1 g/L. [Conclusions] The scheme has been verified to be capable of greatly increasing the yield of the corresponding long-chain dibasic acids of the C. tropicalis engineering strain.展开更多
目的:探讨广州社区围绝经期、绝经后妇女骨骼健康的相关影响因素。方法:以广州2个社区470例围绝经期、绝经后妇女为研究对象,采用法国Diagnostic Medical Systems(DMS)公司生产的UBIS5000型超声骨密度/骨质量测定仪对右跟骨的BUA进行测...目的:探讨广州社区围绝经期、绝经后妇女骨骼健康的相关影响因素。方法:以广州2个社区470例围绝经期、绝经后妇女为研究对象,采用法国Diagnostic Medical Systems(DMS)公司生产的UBIS5000型超声骨密度/骨质量测定仪对右跟骨的BUA进行测定,通过问卷调查影响骨骼健康的相关因素。结果:在与骨骼健康相关的因素中,年龄、初潮年龄、绝经年限、产次与骨密度呈负相关,体重、身高、体重指数、是否素食呈正相关,其中危险因素为初潮年龄和年龄,保护因素为高体重和非素食。结论:社区围绝经期、绝经后妇女骨骼健康与多种因素有关,应综合考虑采取相应措施进行防治,体重及饮食为可控因素,重视可控因素是防治骨质疏松的有效途径。展开更多
基金the National Natural Science Foundation of China(50476032)China Postdoctoral Science Foundation(2004035555)New Century of Talents Scheme Projects of Universities in Liaoning Province(RC-04-04)
文摘In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.
文摘Water-soluble polysaccharide was isolated from grapefruit with the method of water-dissolving and ethanol-precipitating. By single factor test and orthogonal experimental method, the extraction conditions of the water-soluble polysaccharide were investigated, which contained liquid-solid ratio, temperature, time and pH. The results showed that pH was the most important factor of polysaccharide extraction, followed by temperature. The optimized extraction technology conditions were obtained. The liquid-solid ratio was 1:40, temperature was 90?C, time was 2.0 h, and pH was 2. The highest extraction rate of crude polysaccharide was 8.30%.
文摘[Objectives] The fermentation conditions of Candida tropicalis 1798-pxa1 were optimized to further improve its yield of long-chain dibasic acids. [Methods] The strains used in the study were C. tropicalis 1798, C. tropicalis 1798-pxa1 and C. tropicalis 1798-pxa1 p2. First, through single factor experiments, the activated three fungi were cultured in different carbon sources, and the absorbance was measured every 2 h. The growth curve was drawn by software, and finally the most suitable substance for the substrate was selected, i.e., dodecane. Then, the composition of the fermentation medium and the fermentation process parameters were determined through the PB experiment of the single-deletion C. tropicalis 1798-pxa1. [Results] The experiment determined the important components affecting the synthesis of long-chain dibasic acids, namely(NH_4)_2SO_4, NaCl and dodecane. After optimization of the culture conditions, the yield of long-chain dibasic acids of C. tropicalis 1798-pxa1 increased from 5.6 to 10.1 g/L. [Conclusions] The scheme has been verified to be capable of greatly increasing the yield of the corresponding long-chain dibasic acids of the C. tropicalis engineering strain.
文摘目的:探讨广州社区围绝经期、绝经后妇女骨骼健康的相关影响因素。方法:以广州2个社区470例围绝经期、绝经后妇女为研究对象,采用法国Diagnostic Medical Systems(DMS)公司生产的UBIS5000型超声骨密度/骨质量测定仪对右跟骨的BUA进行测定,通过问卷调查影响骨骼健康的相关因素。结果:在与骨骼健康相关的因素中,年龄、初潮年龄、绝经年限、产次与骨密度呈负相关,体重、身高、体重指数、是否素食呈正相关,其中危险因素为初潮年龄和年龄,保护因素为高体重和非素食。结论:社区围绝经期、绝经后妇女骨骼健康与多种因素有关,应综合考虑采取相应措施进行防治,体重及饮食为可控因素,重视可控因素是防治骨质疏松的有效途径。
