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941.
Neutron radiography is one of radiography non-destructive testing. It is a valuable complementary of X and γ rays radiography. The present status and history of neutron radiography in China was described briefly, facilities of neutron radiography and their development were introduced in this paper. 相似文献
942.
铁观音茶多糖的酶法提取及脱蛋白工艺研究 总被引:8,自引:3,他引:5
采用纤维素酶水解方法提取铁观音茶多糖,并对其脱蛋白工艺进行了研究.酶法提取的正交实验结果表明,铁观音茶多糖的得率随酶用量和水解时间的增加而增大,随pH值和温度的升高先增后降,最佳的酶处理条件为:加酶量15 mg/g,pH=4.0,水解温度45℃以及水解时间90 min.比较了Sevag法、三氯醋酸法以及酶与三氯醋酸结合法对铁观音茶多糖的脱蛋白效果,结果表明,三氯醋酸法可以简单高效地去除蛋白质,而又不会造成多糖过多损失,4 mol/L三氯醋酸溶液的最佳使用量为2%(v/v). 相似文献
943.
超声波辅助提取龙眼核棕色素的研究 总被引:2,自引:0,他引:2
以龙眼核为原料,采用超声辅助法提取其中的棕色素.在单因素实验基础上,通过响应面法优化其提取工艺.结果表明:色素提取率随着提取温度、提取时间和超声功率的延长而增加,响应面分析得到的回归模型能够较好地预测实际提取率,最佳工艺条件为提取温度69℃,提取时间52min ,超声功率162W. 相似文献
944.
The microstructure and crack behaviour of twinning induced plasticity (TWIP) steel during tensile deformation was investigated with in-situ scanning electron microscopy (SEM). The results show that there are two modes of plastic deformation during tensile test in the Fe-Mn-C TWIP steel: dislocation gliding and deformation twins. During the process of tensile deformation, secondary deformed twins are found. Inclusions have played a role in the course of ductile fracture, and microcracks initiate from inclusions and twin-twin intersections. 相似文献
945.
As an industry-university cooperative project, an experimental research was conducted to develop a new cold-rolled transformation-induced plasticity (TRIP) steel with a tensile strength of 780 MPa and an elongation of 25% under the conditions that some processing parameters were preestablished according to the actual conditions of factory production lines. The optimal heat treatment conditions for obtaining excellent strength-ductility balance, specifically in intercritical annealing temperature and isothermal treatment temperature, were investigated by means of thermal simulation tests. Ultimately the desirable mechanical properties were attained successfully, and the microstructure and retained austenite stability were studied by optical microscopy (OM) and electron back-scattered diffraction (EBSD). It has been discovered that the sizes of retained austenite grains are generally proportional to the sizes of carbon-clear space (ferrite and bainite) around them, and there is marked selectivity in their transition sequences under stress-strain. 相似文献
946.
实施积极的健康老龄化战略,确保所有老年人“老有所养、病有所医、老有所乐、老有所为”是老年群体公平分享社会经济发展成果的诉求,也是不断改善民生、增进国民福利的保障。运筹发展西藏老年服务产业不仅能应对即将到来的“少子老龄化”社会带来的一系列棘手问题,使老年人能健康快乐地安度晚年,以促进代际、代内公平和社会和谐。而且,老年服务产业在实现养老风险社会化分担从而减轻家庭养老压力的同时,还能创造大量的就业岗位和拉动社会需求。为此,文章提出西藏老年服务产业发展的基本思路:政府支持、战略牵引、需求导向、人文关怀、社会参与。 相似文献
947.
Yingying Zhang Wei Zhang Cuanying Geng Tongjun Lin Xiaowen Wang Lingyun Zhao Jintian Tang 《自然科学进展(英文版)》2009,19(12):1699-1704
To determine whether conventional hyperthermia (42-45℃) or ablation therapy (>50℃) achieves better synergistic effects on direct cytotoxicity and anti-tumor immunity,we compared the therapeutic effects of two hyperthermia temperatures,43 and 55℃,in terms of cytotoxicity and upregulation of immune functions in a mouse malignant melanoma model.Melanoma-bearing mice were treated by directly applying regional hyperthermia to the tumor nodule with a heating light at a temperature of 43℃ for 30 min or 55℃ for 10 min.The tumor growth curve and mice survival rate were observed.To investigate the hyperthermia-induced immunological response,peripheral blood CD4~+ and CD8~+ T cells and the serum IL-2 level were determined.Our results indicated that application of regional hyperthermia at the ablation temperature (such as 55℃) achieved better synergistic anti-tumor effects than did conventional hyperthermia (43℃).Significant increases in the number of peripheral blood CD4~+ T cells and the serum IL-2 level likely contributed to the underlying mechanism. 相似文献
948.
Production of human lysozyme-transgenic cloned porcine embryos by somatic nuclear transfer 总被引:1,自引:0,他引:1
Qiuyan Li Hengxi Wei Ying Guo Yan Li Rui Zhao Yufang Ma Zhengquan Yu Bo Tang Lei Zhang Yunping Dai Ning Li 《自然科学进展(英文版)》2009,19(6):699-704
Due to their physiology and organ size, pigs have significant potential as human disease models and as organ transplantation donors. Genetic modification of pigs could provide benefits for both agriculture and human medicine. In this study, five fetal pig fibroblast cell lines from two species (Wuzhishan and Landrace pigs) were transfected using double-marked human lysozyme (HLY) plasmids (pBC1-HLY-GFP-NEO) by a liposome-mediated method. The ratio of green fluorescent protein (GFP)-expressing cells was >95% in sw7, sw8, slw3 and slw6 cell lines, but only 49.3% in slw9 cells. Cells from the four highly transgenic lines were used as nuclear donors to construct embryos, which were then cultured after fusion and activation by electric stimulation. The rate of cleavage was 76.7%, 48 h after activation. After 7 days, 18.5% of cleaved eggs had developed to the blastocyst stage and 93.3% of blastocysts were GFP-positive. These results indicate that transgenic fetal pig fibroblast cell lines could be obtained by a liposome-mediated method, though the transfection efficiency varied between cell lines. Reconstructed embryos derived from transgenic cells could successfully develop into blastocysts, most of which were GFP-positive. 相似文献
949.
湖南省科技中介服务发展现状及其发展建议 总被引:2,自引:1,他引:1
一个功能较完善、机构充分发展、服务质量较高的科技中介服务体系,是区域创新体系不可或缺的重要组成部分,是推进地区新型工业化、构建特色区域知识经济体系的重要支撑。当前,湖南科技中介机构的发展与创新需求还存在很大差距,认识不到位、体系不完善、基础薄弱、服务质量不高、社会信誉度偏低、相关政策法规体系不完善等问题较突出。加强科技中介机构的自身服务能力建设,进一步规范政府部门的引导职能,努力构建湖南特色新型科技中介服务体系是建设创新型湖南的迫切需要,是加速湖南特色新型工业化进程的重要保障。 相似文献
950.