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641.
642.
CHENXin SUNZhiqiang CHENZhimin ZHANGKai YANGBai 《科学通报(英文版)》2005,50(8):765-769
By combining vertical deposition with micromolding in capillaries method, we have demonstrated the two-substrate vertical deposition, an alternative and versatile procedure for fabricating high-quality stable colloidal crystal chips. Apparent bright colors, special UV-vis spectra, scanning electron microscopy (SEM) and atomic force microscopy (AFM) images all prove that high-quality colloidal crystal structures are formed in between the two substrates.During the two-substrate vertical deposition for colloidal crystal chips, capillary force and evaporation of the medium are critical to the formation of the colloidal crystals; while the confinement in between two close substrates makes the resulting colloidal crystal chips more stable. Due to the excellent stability, these colloidal crystal chips can be used to construct some composite optical devices via a simpler and more flexible process. Meanwhile, they can also be further used as the templates for ordered multiporous materials. 相似文献
643.
白战锋 《西安联合大学学报》2006,9(1):53-55
农业长期大而不强导致我省农民及财政收入增长缓慢,整体经济实力低下;农业经济发展的内在要求决定了陕西农业产业化经营的目标是依托资源优势;推进产加销、贸工农一体化;模式是以农产品加工业为突破口,着力发展养殖种植业,实现粮果生产、畜禽养殖、药材种植的有机结合。当前应营造良好的经济与社会环境,完善区域布局,建立市场化资产运营与利益协调机制,增加农业资金投入,加速培育农产品加工龙头企业。 相似文献
644.
TANGJun YUXiaoqiang LINWeiran SUNJingzhi YANGBai 《科学通报(英文版)》2003,48(20):2168-2170
A water-soluble oligo(p-phenylkene vinylene)[4,4′-(1,4-phenylene dithenylene)-bis-(N-methyl pyridinium iodide)] was synthesized by Witting reaction. The oligomer was characterized by NMR, elemental analysis, UV-visible spectrum, surface photovoltage spectrum and fluorescence spectrum. 相似文献
645.
Exocytosis-the release of the contents of a vesicle--proceeds by two mechanisms. Full fusion occurs when the vesicle and plasma membranes merge. Alternatively, in what is termed kiss-and-run, vesicles can release transmitter during transient contacts with the plasma membrane. Little is known at the molecular level about how the choice between these two pathways is regulated. Here we report amperometric recordings of catecholamine efflux through individual fusion pores. Transfection with synaptotagmin (Syt) IV increased the frequency and duration of kiss-and-run events, but left their amplitude unchanged. Endogenous Syt IV, induced by forskolin treatment, had a similar effect. Full fusion was inhibited by mutation of a Ca2+ ligand in the C2A domain of Syt I; kiss-and-run was inhibited by mutation of a homologous Ca2+ ligand in the C2B domain of Syt IV. The Ca2+ sensitivity for full fusion was 5-fold higher with Syt I than Syt IV, but for kiss-and-run the Ca2+ sensitivities differed by a factor of only two. Syt thus regulates the choice between full fusion and kiss-and-run, with Ca2+ binding to the C2A and C2B domains playing an important role in this choice. 相似文献
646.
铸铁中开花状石墨的微观结构 总被引:3,自引:0,他引:3
用射透电子显微镜和扫描电镜研究了铸铁中开花状石墨的微观结构,结果表明,开花状石墨是石墨沿(0001)方向生长速率增大的过程,因而它是1种过球化石墨,而不是铸铁过程中球化不良造成的。 相似文献
647.
Fractal geometry was applied and box dimension was used as an indicator to analyze the effects of doubled CO2 concentration on the root growth of plant seedlings. Results showed that doubled CO2 concentration displayed different effects on root branching characteristics of C3 and C4 plants. There was an obvious increase of root branches in spring wheat while there were no significant effects on roots of
sweet sorghum. In different soil layers, root branching of spring wheat was stimulated and this promotion was most significant
in the second layer (10–20 cm), which denoted that elevated CO2 altered the root branching pattern. That means higher CO2 concentration influences not only root growth but also its differentiation and development. 相似文献
648.
Under different conditions, oligonucleotides can form several different DNA structures such as duplex, triplex and quadruplex.
All these structures exhibit an obvious difference in their CD spectra. The common characteristic is that they show a negative
band at 240 nm, while in the range of 260–300 nm, the spectra are different from each other. Many factors such as chain direction,
sugar puckering mode, orientation of the glycosyl bond, base stacking and sequence can affect their conformation and then
show diversity and complexity in their spectra. By studying and comparing these spectra, more information about their conformations
can be obtained to help predict some new structures. Furthermore, the spectra can also provide a base to study their potential
biological functions. 相似文献
649.
(n,1,1)共轭边值问题多个正解的存在性 总被引:1,自引:1,他引:0
考虑方程u(n)+f(t,u)=0在边值条件u(k)(0)=0,0≤k≤n-2,u(1)=0下多个正解的存在性.假定f在一端(零点或无穷远点)超线性增长,而在另一端次线性增长,则上述问题至少有两个正解 相似文献
650.
分布式并行CAIP系统协同求解模型的研究 总被引:1,自引:0,他引:1
采用STRIPS规划系统语法格式和图论知识,论述了基于知识的通用检测规划的领域模型、抽象分层规划以及相应的任务分解算法,从而建立了基于分布式并行处理智能检测规划集成开发平台IDPIP的分布式并行协同求解模型. 相似文献