排序方式: 共有21条查询结果,搜索用时 421 毫秒
11.
胆固醇(Cholesterol)嵌入卵磷脂(PC)有序体后对其中CaCO3晶型结构的影响 总被引:1,自引:0,他引:1
在PC和Chol/PC有序体中进行CaCO3沉淀反应,用X射线衍射和扫描电镜方法表征了反应物结构,研究了作为有机模板剂的不同分子有序体对CaCO3的晶型和形态的指导作用.在反胶束合成中出纳米级CaCO3颗粒.胆固醇对有序体有显著影响,进而影响此体系中形成的CaCO3晶型,可诱导生成3种CaCO3异构体:胶体CaCO3、球霰石和方解石.方解石含量随胆固醇含量增加减少. 相似文献
12.
进行了水溶液体系中三价稀土离子(Sm3+)对草酸钙(CaC2O4)结晶过程影响效应的研究. 采用微量热法、X射线衍射(XRD)以及扫描电镜(SEM)法, 研究了Sm3+对草酸钙结晶过程动力学的影响效应及对草酸钙晶体晶型、形貌、尺寸的调控作用. 微量热研究结果表明, Sm3+对草酸钙结晶过程的影响包括对晶体初期成核以及晶体生长过程的影响, 在适宜的浓度(约2.50×10-5 mol•L-1)下达到对晶体成核与生长的最佳抑制效果; XRD研究结果表明, Sm3+的加入有利于草酸钙二水合物(COD)的生成; SEM形貌研究表明, Sm3+对草酸钙晶体的形态、尺寸产生非常显著的调控作用. 相似文献
13.
14.
Homogeneous chitosan-silk fibroin/hydroxyapatite(CS-SF/HA) composites were prepared by in situ precipitation method driven by a multiple-order template. The morphology of the composites was investigated by scanning electron microscope(SEM) and transmission electron microscope(TEM). The compositional analysis was carried out by X-ray diffraction analysis(XRD) and Fourier transformed infrared spectroscopy(FTIR). The mechanical properties and biocompatibility of the composites were also determined. The results indicated that the inorganic particles of uniform size(50 nm) were well-dispersed among the CS-SF matrices. The compressive modulus of the CS-SF/HA composites was enhanced with the increasing amount of SF. The in vitro results suggested that the MC3T3-E1 osteoblast-like cells on CS-SF/HA composite disks displayed strong bonding and spreading, and the cell proliferation cultured on each composite disk increased throughout the culture period for up to 7 days. Especially, the samples with higher content of SF had much better biological properties. The evidences proved that the CS-SF/HA composites possessed excellent biocompatibility. By using the freeze-drying technique, hierarchical porous scaffolds with pores ranging from 50 μm to 200 μm were obtained. This work presented the advantages of in situ precipitation method to prepare the organic/inorganic composites, and a multiple-order template was introduced in the system to improve the properties of the composites by combining the merits of each organic template. 相似文献
15.
16.
不同电解质溶液对脂质体Zeta电势的影响 总被引:4,自引:0,他引:4
卵磷脂(PC)在水溶液中形成类似细胞的脂双层闭合体——脂质体.以它为模型研究水溶液中无机离子与磷脂分子极性端基的作用,对解释生理环境中脂质体的物理化学行为有重要的意义.Tatulian[1]用电泳法给出了一系列一价阴离子与PC膜表面亲合强弱的排序,Eisenberg等[2]测定了一 相似文献
17.
18.
气体钻井钻柱的静动力学特性研究 总被引:2,自引:0,他引:2
针对气体钻井钻具振动剧烈及频繁失效的实际问题,建立了全井段钻柱系统静力学模型和三向耦合振动的力学模型,研究了循环介质阻尼作用的计算公式。以川东某实钻井气体钻进段为例,利用考虑泥浆作用的振动模型与美国埃索公司现场数据和规律进行了对比,验证了全井段钻柱系统三向耦合振动力学模型的可行性与结果的可靠性;量化研究了全井钻柱的静力学特性与动力学特性,并与同工况参数下泥浆钻井钻柱的静力学特性和振动规律进行了对比。研究发现,气体钻井各钻具轴向力和轴向应力均高于泥浆钻井,且纵振、横振、扭振及涡动的幅频均强于泥浆钻井;工作过程中,气体钻井钻柱承受更大幅值的交变应力,这是导致钻具频繁失效的根源之一。 相似文献
19.
20.