排序方式: 共有84条查询结果,搜索用时 15 毫秒
71.
提出了一种基于小波阈值密度估计的结构可靠性分析高效自适应重要抽样方法.该方法利用非线性小波收缩方法对结构失效域样本进行密度估计,并以此作为重要抽样密度进行可靠性分析.与传统基于核密度估计的重要抽样方法比,由于非线性小波阈值密度估计具有较好局部适应性和最优收敛速度,且克服了核密度估计中计算精度严重依赖于参数选择的缺陷,因此以较少的预抽样样本就能获得与传统方法相当的精度,有效提高计算效率.数值算例表明所提方法对工程中常遇到的多设计点及噪音功能函数可靠性问题具有良好适应性. 相似文献
72.
Shuangfeng Cai Yaran Wu Yanan Li Shuying Yang Zhi Liu Yuwen Ma Jianqiang Lv Yujia Shao Hongzhe Jia Yan Zhao Lei Cai 《Molecules (Basel, Switzerland)》2021,26(23)
The chlorophyll ethanol-extracted silkworm excrement was hardly biologically reused or fermented by most microorganisms. However, partial extremely environmental halophiles were reported to be able to utilize a variety of inexpensive carbon sources to accumulate polyhydroxyalkanoates. In this study, by using the nile red staining and gas chromatography assays, two endogenous haloarchaea strains: Haloarcula hispanica A85 and Natrinema altunense A112 of silkworm excrement were shown to accumulate poly(3-hydroxybutyrate) up to 0.23 g/L and 0.08 g/L, respectively, when using the silkworm excrement as the sole carbon source. The PHA production of two haloarchaea showed no significant decreases in the silkworm excrement medium without being sterilized compared to that of the sterilized medium. Meanwhile, the CFU experiments revealed that there were more than 60% target PHAs producing haloarchaea cells at the time of the highest PHAs production, and the addition of 0.5% glucose into the open fermentation medium can largely increase both the ratio of target haloarchaea cells (to nearly 100%) and the production of PHAs. In conclusion, our study demonstrated the feasibility of using endogenous haloarchaea to utilize waste silkworm excrement, effectively. The introduce of halophiles could provide a potential way for open fermentation to further lower the cost of the production of PHAs. 相似文献
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74.
Li W Jin L Zhu N Hou X Deng F Sun H 《Journal of the American Chemical Society》2003,125(41):12408-12409
Colloidal bismuth subcitrate (CBS, De-Nol) has been used for several decades for the treatment of gastric and duodenal ulcers, and Helicobacter pylori infection together with antibiotics. The solubility of CBS in water is found to be dramatically affected by pH, from >70 mg/mL at pH 7 to only about 1 mg/mL at pH 3. CBS was crystallized in dilute HCl at pH 3, and unique assembly of three basic bismuth citrate dimeric units ([Bi(cit)2Bi]2-) leads to the formation of two-dimensional sheets and 3D polymer. 相似文献
75.
A novel form of nano-sized carbon rods decorated with monodispersed iron particles in a size range of 30-50 nm on their surface is successfully synthesized by arcing discharge of composite electrodes made from iron particles and fullerene soot; this will be of potential as catalyst for hydrogenation reactions. 相似文献
76.
Encapsulation of platinum anticancer drugs by apoferritin 总被引:1,自引:0,他引:1
Yang Z Wang X Diao H Zhang J Li H Sun H Guo Z 《Chemical communications (Cambridge, England)》2007,(33):3453-3455
Apoferritin derived from the native protein ferritin was employed to encapsulate anticancer drugs cisplatin and carboplatin. 相似文献
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78.
Fan Qin Guangfang Li Runming Wang Jiliang Wu Prof. Hongzhe Sun Prof. Rong Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(51):16491-16497
Uniform bismuth oxide (Bi2O3) and bismuth subcarbonate ((BiO)2CO3) nanotubes were successfully synthesized by a facile solvothermal method without the need for any surfactants or templates. The synergistic effect of ethylene glycol (EG) and urea played a critical role in the formation of the tubular nanostructures. These Bi2O3 and (BiO)2CO3 nanotubes exhibited excellent CrVI‐removal capacity. Bi2O3 nanotubes, with a maximum CrVI‐removal capacity of 79 mg g?1, possessed high removal ability in a wide range of pH values (3–11). Moreover, Bi2O3 and (BiO)2CO3 nanotubes also displayed highly efficient photocatalytic activity for the degradation of RhB under visible‐light irradiation. This work not only demonstrates a new and facile route for the fabrication of Bi2O3 and (BiO)2CO3 nanotubes, but also provides new promising adsorbents for the removal of heavy‐metal ions and potential photocatalysts for environmental remediation. 相似文献
79.
We mainly discuss entire solutions with finite order of the following Fermat type differential-difference equationswhere m, n are positive integers.
相似文献
$$\begin{array}{ll}(f)^{n}+f(z+c)^{m}=1;\\f^{\prime}(z)^{n}+f(z+c)^{m}=1;\\ f^{\prime}(z)^{n}+[f(z+c)-f(z)]^{m}=1,\end{array}$$
80.
An integrated light emitting diode (LED)-induced fluorescence detector was described and evaluated. The LED and its related components including lens and interference filter, the optical fiber used to collect fluorescence, and the capillary column are integrated into a substrate block, which eliminates the need of align procedure of the fiber and the capillary. Forty-fold enhancement of sensitivity was obtained compared with our previous work and the detection limit for fluorescein was 5 nM. Application of the detector for the analysis of FITC-labeled Ephedrine extract was demonstrated. 相似文献