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排序方式: 共有236条查询结果,搜索用时 62 毫秒
1.
在溶剂热条件下,以含卤素有机羧酸3-溴-吡啶-2,6-二甲酸(H2L)为配体,以硝酸钴、硝酸铜为金属源,合成了两例配合物:[Co(L′)3](1)和[Cu(L′)2]n(2)(HL′=5-溴-吡啶-2-甲酸),通过元素分析(EA)、X射线单晶衍射(SXRD)、X射线粉末衍射(PXRD)、红外光谱(IR)和热重分析(TGA)进行结构表征。X射线单晶衍射结果表明,配体H2L在反应过程中发生脱羧现象,生成单羧酸配体5-溴-吡啶-2-甲酸。在配合物1中,每个Co(Ⅲ)都位于略微扭曲的八面体几何构型中,不对称单元中含有两个单核单元,单核单元通过C—H…O氢键形成三维超分子结构。配合物2的不对称单元中含有一个Cu(Ⅱ),两个脱质子的L′-配体,每个Cu(Ⅱ)都是六配位的,位于扭曲的八面体几何构型中。Cu(Ⅱ)由配体连接生成1D链结构,通过C—H…O氢键形成三维超分子结构。此外,研究了两例配合物的热稳定性能。 相似文献
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Zan Ting-quan 《应用数学和力学(英文版)》1988,9(10):985-992
This series of papers is prepared to develop systematically the complicated dynamical behaviors of nonlinear ecosystem and its internal mechanism. In this paper, we state briefly the increasing importance of ecology, describe and comment on the situations and reasons why ecology theory is behind practice. Then, we point out a procedure which modern ecology research should obey, and discuss the four basic characteristics of ecosystem in detail: level, opening, nonlinear and far from equilibrium. At last, we discuss systematically equilibrium and nonequilibrium, stable and unstable, environmental stochasticity and dynamical stochasticity, and conclude that there exists a bridge between deterministic behaviors and stochastic behaviors, which will result in a new model for ecological prediction.Supported by Youth Fund of Chinese Academy of Science and Youth Fund of Lanzhou University. 相似文献
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Wen-Wen Zhao Ke Zan Jing-Yue Wu Wei Gao Jie Yang Yin-Ying Ba 《Natural product research》2019,33(17):2435-2439
One new triterpenoid (1) and seven known analogues (2–8) were isolated from the leaves of Ilex hainanensis Merr.. Their structures were established by analysis of their MS, 1D and 2D NMR spectroscopic data and comparison with those in the literature. The antibacterial activity of compounds 1–8 were evaluated by determination of minimum inhibitory concentration using twofold microdilution broth method against Streptococcus mutans ATCC 25175 (Gram-positive) and Fusobacterium nucleatum ATCC 10953 (Gram-negative). Compounds 3 and 5 showed significant antibacterial activity against S. mutans in concentration of 9.7 μg/mL, while showed little antibacterial activity against F. nucleatum. On the contrary, the inhibitory activity of compounds 1, 2 and 6 against F. nucleatum were higher than them against S. mutans. 相似文献
4.
Zhang Hong-Kun Gong Xian-Yun Li Zan Wang Yang 《Russian Journal of Applied Chemistry》2020,93(4):611-623
Russian Journal of Applied Chemistry - A novel curing agent containing phosphorus and carboxyl group compound diphenyl(2,3-dicarboxylpropyl)phosphine oxide (DPDCPPO) was synthesized and used as a... 相似文献
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传统DEA模型在数据两分(偏好与规避)的基础上考察决策单元的有效性,在某些场合不再适用,文章根据决策者的偏好将数据分为三类:规避、偏好、中性类,在此基础上构造评价相对有效性的DEA模型.相较而言,基于数据三分法的DEA模型更具一般性,利用该模型,文章考察了中国近年投入产出绩效问题. 相似文献
7.
Acid‐treated g‐C3N4‐Cu2O composite catalyst with enhanced photocatalytic activity under visible‐light irradiation 下载免费PDF全文
Shiyu Zuo Haiming Xu Wei Liao Lei Sun Donghui Han Jie Zan Binyang Zhang Dongya Li Dongsheng Xia 《应用有机金属化学》2018,32(9)
Acid‐treated g‐C3N4‐Cu2O was prepared by hydrothermal reduction followed by high temperature calcination and acid exfoliation. The structures and properties of as‐synthesized samples were characterized using a range of techniques, such as X‐ray photoelectron spectroscopy, scanning electron microscopy, Photoluminescence Spectroscopy and the Brunauer–Emmett–Teller (BET) theory. The photocatalytic activity was evaluated by measuring the photodegradation of methyl orange under visible‐light irradiation. Based on the results of TEM, XPS, EPR and other techniques, it was verified that a heterojunction was formed. The acid treatment process can increase the specific surface area to form abundant heterojunction interfaces as channels for photo‐generated carrier separation, thereby enhancing its light utilization and quantum efficiency. Results indicate that acid‐treated g‐C3N4‐Cu2O possesses a large specific surface area, which provides plentiful activated sites for heterojunctions to form; in addition, it showed a high visible light effect and the minimum charge‐transfer resistance. Furthermore, the g‐C3N4‐Cu2O material exhibits high levels of effectiveness and stability. Electron paramagnetic resonance and a series of radical trapping experiments demonstrate that the holes and ?O2? could be the main active species in methyl orange photodegradation. This work could provide new insights into the fabrication of composite materials as high‐performance photocatalysts, and facilitate their application in addressing environmental protection issues. 相似文献
8.
本文发现了Zn(II)离子掺杂可以加快聚乳酸的结晶过程. 测试了三种Zn(II)盐(ZnCl2、ZnSt和ZnOAc),并与其它离子Mg(II)和Ca(II)进行对照. FT-IR以及变温拉曼光谱分析发现,经Zn(II)离子掺杂后,聚乳酸的结晶度和结晶速率均增加,差示扫描量热技术以及X射线衍射分析也进一步证实. 差示扫描量热技术测定PLA/ZnSt-0.4 wt%材料的结晶率达到22.46%,PLA/ZnOAc-0.4 wt%材料的结晶率达到24.83%. 相似文献
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THERMODYNAMIC ENTROPY MODELS OF THE FROZEN-WALL SYSTEM (Ⅰ) 总被引:2,自引:2,他引:0
Zan Ting-quan 《应用数学和力学(英文版)》1987,8(8):785-792
In this paper, the author describes, and comments on the traditional thermal theory on artificial ground freezing, and points out its important significance and shortcomings. The frozen-wall is analysed by system analysis methods. According to matter levels, the frozen-wall is divided into three sub-systems: frozen colloid system, frozen soil system and frozen-wall system. They correspond to different characteristics. The frozen-wall system is a large open system with multi-levels and multi-aspects. The problems of stability of the system and its control are the key problems in the techniques of artificial ground freezing. Based on non-equilibrium thermodynamics and dissipative structure theory methods, the author discusses and reveals the problems of the formation and stability of the frozen-wall system and its thermodynamic nature, and proposes the thermodynamic entropy models of the system. The result is a great satisfaction. 相似文献