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71.
本文研究了非晶态离子导体Li2B2O4的离子电导率与温度的关系,特别着重于晶化前期的离子迁移特性。当温度低于TK(≈310℃)时,离子电导率遵从Arrhenius关系。当高于晶化温度(≈411℃)时,以晶态中的离子迁移为主。在Tkc时,电导率偏离热激活机制呈反常增高。我们把这一过程称为晶化前期过程。可以用自由体积模型进行描述。晶化前期又可分为两部分:当温度低于、Tp(≈380℃)时,由于自由体积的重新分布,导致了电导率的增高;当T>Tp时,出现了少量微晶,但晶化量小于5%,由于非晶母体与微晶之间的界面效应使得离子导电性显著增强。可以通过室温淬火,把晶化前期非晶态的状态保持到室温,从而有可能制备出离子电导率高于纯非晶态的材料。
关键词: 相似文献
72.
本文用X射线粉末法测定了Li2K(IO3)3与Li2NH4(IO3)3的晶体结构和原子参数。发现Li3K(IO3)3,Li2NH4(IO3)3与Li2Rb(IO3)3同晶型,属单斜晶系,空间群为P21/α,每个单胞含有四个化合式量。室温的点阵常数分别为α=11.198?,b=11.046?,c=8.254?,β=111.53°,及α=11.327?,b=11.078?,c=8.341?,β=111.87°。讨论了二元化合物的形成与离子半径的关系。
关键词: 相似文献
73.
对12C6+ 离子辐照诱变高产阿维链霉菌株ZJAV-Y1-203 和原始菌株ZJAV-A-1 的摇瓶发酵pH 值、菌体浓度、碳源和氮源代谢进行了测定,研究了12C6+ 辐照对阿维链霉菌的代谢效应。在发酵前期(48h),原始菌株发酵液pH 值低于突变菌株;在发酵96~196 h,诱变高产菌株ZJAV-Y1-203 繁殖快,生长旺盛,N的利用率高;菌体浓度大于原始菌株的浓度,且发酵液的pH 稳定,菌体处于代谢相对更稳定期;在发酵144~240 h,诱变高产菌株ZJAV-Y1-203 对糖源消耗低于原始菌株ZJAV-A-1。这些结果表明,12C6+ 离子辐照对阿维链霉菌代谢影响有利于阿维菌素合成。pH value, mycelium concentration, carbon source and nitrogen metabolism in flask fermentation of the mutant high-producing strain ZJAV-Y1-203 and the original strain ZJAV-A1 have been investigated, in order to show the metabolic effect of avermitilis irradiated by ion beam of 12C6. In early stage (48 h) of the fermentation, pH value of the original fermentation was lower than that of the mutant strains. In 96~196 h of fermentation, the nitrogen utilization in the strains ZJAV-Y1-203 was higher than that in the original strains, its reproductive was fast, and its growing was vigorous. The mycelium concentration of ZJAV-Y1-203 was greater than the original strain, and the pH value of fermentation were stable, so its metabolism was relatively more stable. In 144240 h of fermentation, the strain ZJAV-Y1-203 on sugar consumption was less than the original strains. The effect of 12C6 ion irradiation on metabolism of Streptomyces avermitilis is conducive to the synthesis of avermectin. 相似文献
74.
大型运动会要求主办方在规定时间内将相关人员从运动员村运送至指定比赛场馆.基于大城市日趋严重的交通拥堵,为满足运送时间的要求,通常在城市公共交通网络中设置专用交通道.但专用交通道的设置会对城市公共交通产生影响,最小化其对城市公共交通影响是专用交通道优化问题的关键.针对此类问题,在给出了改进的混合整数规划模型的基础上,提出了基于问题特性的变长度染色体混沌遗传算法,包括变长度染色体编码、混沌个体初始化、交叉操作、变异操作、适应度函数的计算和不可行解的惩罚、修复策略等.最后,以经典算例和随机生成算例对算法有效性进行了验证. 相似文献
75.
通过使用Mawhin连续性定理,研究四阶p-Laplacian微分方程多时滞问题(φ_p(x″(t)))″+f(t,x″(t))+(?)β_i(t)g(x(t-γ_i(t)))=p(t)周期解的存在性,并得到了存在周期解的充分性条件 相似文献
76.
Yongtai Zhang Jiansheng Tao Nianping Feng Xiangdong Han 《Crystal Research and Technology》2008,43(9):931-934
The crystallization of calcium oxalate (CaOxa) in aqueous solutions of the extracts of Semen Plantaginis and Folium Pyrrosiae has been investigated, focusing on the inhibition mechanism of some herbs on stone formation. It has been shown that in the presence of extracts of above two herbs, calcium oxalate dihydrate (COD) crystals with typical morphologies of tetragonal bipyramids were obtained. This suggests that the extracts of Semen Plantaginis and Folium Pyrrosiae can promote the formation of thermodynamically unstable COD, and inhibit the formation of calcium oxalate monohydrate (COM), a major component of urinary stone. The formation mechanism of COD crystals induced by Semen Plantaginis and Folium Pyrrosiae is also discussed, indicating that the bioorganic molecules in the extracts of the herbs can induce the nucleation and growth of COD crystals. This study can help us make clear the inhibition mechanism of some herbs on stone formation that is in favor of the prevention and treatment of urolithiasis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
77.
ZHANG Tianren ZHANG Chunxue CHE Xiangyang BAI Binglian LI Min WANG Haitao 《高等学校化学研究》2019,35(5):874-878
The synthesis and gelation properties of a series of organogelators containing a benzohydrazide unit and two alkoxy chains(oBn) were reported herein. oBn(n=8, 10, 12) could form stable gels in commercial fuels(e.g., diesel), which were characterized by low critical gelation concentrations(CGCs) and good mechanical properties (G'>105 Pa). The gelation process was further studied by field-emission scanning electron microscopy(FE-SEM), Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction(XRD), etc. It was demonstrated that in these organogels, molecules self-assembled into fibrils 3D-network, where hydrogen bonding, van der Waals force and π-π interaction were confirmed as the driving forces. As compounds oBn(n=8, 10, 12) show very good gelation properties in diesel, their applications in oil spill treatment have also been tested. It was found that oBn could achieve rapid (<30 s) and effective oil removal at room temperature, being good candidates for oil spill treatment in the future. Also, the removal efficiency could be as high as 95%. 相似文献
78.
TANG Haitong MENG Fanling LIU Yan JIN Shi WANG Xiaodong GAO Zhongmin CHE Xiaolei 《高等学校化学研究》2019,35(6):1070-1075
The void structure of polyacrylonitrile(PAN) fibers was investigated using ultra-small angle X-ray scattering(USAXS) and small angle X-ray scattering(SAXS). A quantitative method was developed to analyze connected USAXS/SAXS data and thus determine the void parameters of PAN fibers. The results showed that voids affected the mechanical performance of PAN fibers and were present throughout the entire wet-spinning process. When the absolute quantity and size of voids decreased, the tensile strength and modulus of PAN fibers increased. The void parameters were optimized by controlling the production process, and thus the tensile strength and modulus of PAN fibers were increased. The method for analyzing the void structure developed in this study is useful for analyzing voids over with larger size range, as well as the effect of the void structure on the mechanical performance of fibers. 相似文献
79.
Common Features in Electronic Structure of the Oxypnictide Superconductors from Photoemission Spectroscopy
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贾小文 ;刘海云 ;张文涛 ;赵林 ;孟建桥 ;刘国东 ;董晓莉 ;吴刚 ;刘荣华 ;陈仙辉 ;任治安 ;衣纬 ;车广灿 ;陈根富 ;王楠林 ;王桂玲 ;周永 ;朱镛 ;王晓阳 ;赵忠贤 ;许祖彦 ;陈创天 ;周兴江 《中国物理快报》2008,25(10):3765-3768
High resolution photoemission measurements are carried out on non-superconducting LaFeAsO parent com- pound and various superconducting RFeAs(O1-ZFx) (R=La, Ce and Pr) compounds. It is found that the parent LaFeAsO compound shows a metallic character. By extensive measurements, several common features are identified in the electronic structure of these Fe-based compounds: (1) 0.2 eV feature in the valence band, (2) a universal 13-16 meV feature, (3) near EF spectral weight suppression with decreasing temperature. These uni- versal features can provide important information about band structure, superconducting gap and pseudogap in these Fe-based materials. 相似文献
80.