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991.
为提高制造系统的快速结构配置规划响应速度,提出了基于商空间理论的可重构机床粒计算方法,实现了体系结构组元模型在系统配置规划中的快速粒度分解、组合,建立了功能分解与结构匹配的商空间模型,全面表达了可重构机床在配置规划中粒度分解的相关特征和目标任务的相关变化,实现了可重构机床的模块快速优化分解. 相似文献
992.
建立了原子荧光光谱法测定茶叶中痕量铅的分析方法.研究氢化物发生体系各试剂对荧光强度的影响,确定最佳的试剂浓度和实验条件.铅在0~10.0ng.mL-1范围内荧光与浓度线性关系良好,线性回归方程为:If=318.13C+22.28.实际样品测定精密度4.7%,回收率为97%~101%;绿茶、普洱茶、球茶铅残留量测定结果分别为:1.41、1.61、1.68mg.kg-1.该分析方法操作简单,灵敏度高,适于样品的批量快速分析. 相似文献
993.
王楠 《贵州大学学报(自然科学版)》2012,29(6):135-140
运用辽宁省2000-2008年农村固定观察户统计资料和数据,基于不同收入水平农户,将全省分为四区域——辽东、辽西、辽南、辽北,分析农户家庭的借贷行为,得出结论:辽宁省农户的借贷水平并未随着收入增长和时间推移呈现明显的上升趋势;借贷方面两极化趋势明显,在农户资金借贷来源中,银行信用社借贷占比较低,民间借贷中的付息比例呈下降趋势;农户借贷用途更多趋向生活,在收入水平低的农户中该现象更加明显;而辽宁省农户的生产性借贷大多用于农林牧渔方面,不存在明显的非农化倾向。 相似文献
994.
SHRIMP zircon U-Pb ages and tectonic implications for Indosinian granitoids of southern Zhuguangshan granitic composite,South China 总被引:4,自引:0,他引:4
Ping Deng JiShun Ren HongFei Ling WeiZhou Shen LiQiang Sun Ba Zhu ZhengZhong Tan 《科学通报(英文版)》2012,57(13):1542-1552
The large southern Zhuguangshan granitic batholith composite consists of granites with ages varying from the Caledonian through Indosinian to Yanshanian. Based on K-Ar dating data, the ages of the major parts of this composite were previously regarded as Yanshanian. In this study, the SHRIMP zircon U-Pb dating method has been adopted for six plutons, Ledong, Longhuashan, Dawozi, Zhaidi, Baiyun and Jiangnan, in the southern Zhuguangshan composite, in which the four plutons other than Baiyun and Jiangnan were previously regarded as Yanshanian granites. Magmatic zircons from these six plutons, dated by this study, have yielded ages of 239±5 Ma (MSWD = 2.5), 239±5 Ma (MSWD = 2.5), 239±2 Ma (MSWD = 1.7), 239±4 Ma (MSWD = 3.2), 231±2 Ma (MSWD = 0.81) and 231±3 Ma (MSWD = 1.8), respectively. The results indicate that these plutons were formed by early Indosinian magmatism. Geochemical characteristics suggest that these granites were formed in an extensional tectonic environment. Therefore, the Indosinian period granites in the southern Zhuguangshan composite were formed by partial melting of the Paleo-Mesoproterozoic crustal components during the collapse of thickened lithosphere after the collision between the South China and Indosinian plates. 相似文献
995.
Wei Zhang ZhiPeng Li ZhiQiang Guan Hao Shen WenBo Yu WeiDong He XiaoPeng Yan Ping Li HongXing Xu 《科学通报(英文版)》2012,57(1):68-71
We used a thin-film thermocouple to detect the thermal effect of surface plasmons excited in Au nanohole array structures.We found that the thermal electromotive force of Au film with periodic nanohole structures is three times greater than that of a bare Au film for 785-nm laser excitation at a given power.This effect is caused by the resonant excitation of localized surface plas- mons in the nanoholes.In addition,we found that the thermal electromotive force(EMF)of the Au film with dumbbell-like na- nohole arrays depends strongly on the incident polarization.The thermal EMF is the greatest when the excitation light is polarized perpendicular to the long axis of the dumbbell. 相似文献
996.
Bisulfite at low concentrations(L-NaHSO3) increases cyclic electron transport around photosystem I(PSI) and photosynthesis.However,little is known regarding the detailed contribution of cyclic electron transport to the promoted photosynthesis by L-NaHSO3.In the present work,we used tobacco mutant defective in ndhC-ndhK-ndhJ(ndhCKJ) to investigate the role of NAD(P)H dehydrogenase(NDH)-dependent cyclic electron transport around PSI in an increase in photosynthesis by L-NaHSO3.After the treatment of tobacco leaves with L-NaHSO3(10 μmol L-1),the NDH-dependent cyclic electron transport,monitored by a transient post-illumination increase in Chl fluorescence and the amount of NDH,was notably up-regulated in wild type(WT).The NDH-dependent cyclic electron transport was severely impaired in ndhCKJ and was not significantly affected by treatment with L-NaHSO3.Accordingly,the NDH-dependent transthylakoid membrane proton gradient(pH),as reflected by the slow phase of millisecond-delayed light emission(ms-DLE),was increased by L-NaHSO3 in WT,but not in ndhCKJ;the enhancement of cyclic photophosphorylation(PSP) activity by L-NaHSO3 was more obvious in WT than ndhCKJ.The accumulation of both superoxide and hydrogen peroxide was reduced in WT when subjected to L-NaHSO3 treatment,but not in ndhCKJ.Furthermore,the increase of photosynthetic O 2 evolution rate by L-NaHSO3 was more significant in WT than in ndhCKJ.We therefore conclude that L-NaHSO3 alleviates the photo-oxidative damage by the enhancement of NDH-dependent cyclic PSP,thereby improving photosynthesis. 相似文献
997.
To clarify the nature of different photocatalytic activities between niobate and tantalate,a comparative study of the water splitting into H2 over strontium niobate and tantalate was performed.These isostructural photocatalysts were prepared by a facile and simple hydrothermal reaction and characterized by powder X-ray diffraction(XRD),N2-sorption,UV-Vis diffuse reflectance spectra(UV-Vis DRS),and transmission electron microscopy(TEM).The effects of crystal structure,Brunauer-Emmett-Teller(BET) surface area,photoabsorption performance,morphology,and electronic structure are discussed. 相似文献
998.
An efficient method was developed for the synthesis of arylidene heterobicyclic 3-cyano-2-pyridones via ytterbium chloride catalyzed tandem condensation of aromatic aldehydes,cyclic ketones,and cyanoacetamide.The conditions and scope of the reaction were investigated and a reaction mechanism was proposed. 相似文献
999.
社会学视野中的民族大学生社会认知 总被引:1,自引:0,他引:1
民族院校是国家专门为少数民族开办的高等教育机构,担负着为少数民族地区培养高级专门人才的任务。从社会学视角出发,从转型社会、和谐社会和风险社会三个维度,探讨了如何联系现实、从多面向引导学生全面认识我国国情,树立正确的国家观、价值观,科学认识社会发展的规律,在建设社会、服务于社会中实现个人价值。 相似文献
1000.