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Zhiwen Chu Ruiqi Tong Yufan Yang Xuanyi Song Tian bao Hu Yu Fan Chen Zhao Lu Gao Zhenlei Song 《中国化学快报》2021,32(1):1-4
A convergent approach to 1,5-hydroxy ketones,the general precursors for constructing the C ring of bryostatins,has been developed via a Zn/Cu-promoted conjugate addition of a-hydroxy iodides with enones.The reaction leads to direct formation of the C21-C22 bond and tolerates diverse functionalities at the C17-,C18-and C24-positions.The approach also enables a more concise synthesis of the known C ring intermediate(10 longest linear steps and 14 total steps),in contrast to its previous synthesis(17 longest linear steps and 22 total steps) in our total synthesis of bryostatin 8. 相似文献
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导出了纤维金属胶接层板双面裂纹搭接剪切(DCLS)试样分层尺寸和柔度之间的线性关系式,提出了DCLS试样分层尺寸的柔度测量法,并与用光测法测得的分层尺寸进行了对比。结果表明,用柔度法测定DCLS试样的分层尺寸,不仅测量结果准确,而且简单易行,避免了光测法的诸多麻烦和精度低的缺点。 相似文献
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Xinping Lin Sasa Liu Ruiqi Bao Ning Gao Sufang Zhang Rongqian Zhu Zongbao Kent Zhao 《Applied biochemistry and biotechnology》2017,181(3):867-883
The biogenic iron oxide/hydroxide materials possess useful combination of physicochemical properties and are considered for application in various areas. Their production does not require special investments because these compounds are formed during cultivation of neurophilic iron bacteria. Bacteria from genus Leptothrix develop intensively in the Sphaerotilus-Leptothrix group of bacteria isolation medium and feeding media of Fedorov and Lieske. These media are different in their composition which determined the present study as an attempt to clear up the reasons that define the differences in the composition of the laboratory-obtained biomasses and the natural biomass finds. FTIRS, Mössbauer spectroscopy, and XRD were used in the research. Comparative analysis showed that the biomass and control samples contain iron compounds (α-FeOOH, γ-FeOOH, β-FeOOH, γ-Fe2O3) in different ratios. The biomass samples were enriched in oxyhydroxides of higher dispersion. Organic residuals of bacterial origin, SO4, CO3, and PO4 groups were registered in the biogenic materials. 相似文献
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Yicun Huang Fanyong Yan Manman Fu Ruiqi Zhang Xuguang Zhou Jinxia Xu 《Journal of the Iranian Chemical Society》2017,14(1):157-176
Because some metal ions are highly toxic even at trace level, a constant demand of developing methods for monitoring and removing these metal ions is extremely urgent. Silica-based optical chemosensors are supposed as good alternatives to classical instrumental methods for detecting and adsorbing metal ions, due to their effect and lower price. Silica nanoparticles, silica gel and mesoporous silica are used as supporting platforms to fabricate optical chemosensors. They have certain properties containing high porosity and expectant adsorption capacity. Chromogenic-type and fluorogenic-type optical probes, such as azobenzene, naphthalimide and rhodamine, are grafted to the surface of silica-based materials by sol–gel reaction, the limit of detection, response time and selective properties of optical sensors are improved sequentially. In this paper, the articles of silica-based optical chemosensors are retrospected since 2008, describing silica-based optical sensors used for sensing metal ions. The sensing mechanism, optical phenomenon, detection limit, adsorption capacity and application are also reviewed. 相似文献
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Qi Zhang Xu Xiao Dr. Ruiqi Zhao Danhui Lv Guanchen Xu Zhixing Lu Lifei Sun Shizhe Lin Xiang Gao Prof. Jun Zhou Prof. Chuanhong Jin Prof. Feng Ding Prof. Liying Jiao 《Angewandte Chemie (International ed. in English)》2015,54(31):8957-8960
Controlled stacking of different two‐dimensional (2D) atomic layers will greatly expand the family of 2D materials and broaden their applications. A novel approach for synthesizing MoS2/WS2 heterostructures by chemical vapor deposition has been developed. The successful synthesis of pristine MoS2/WS2 heterostructures is attributed to using core–shell WO3?x/MoO3?x nanowires as a precursor, which naturally ensures the sequential growth of MoS2 and WS2. The obtained heterostructures exhibited high crystallinity, strong interlayer interaction, and high mobility, suggesting their promising applications in nanoelectronics. The stacking orientations of the two layers were also explored from both experimental and theoretical aspects. It is elucidated that the rational design of precursors can accurately control the growth of high‐quality 2D heterostructures. Moreover, this simple approach opens up a new way for creating various novel 2D heterostructures by using a large variety of heteronanomaterials as precursors. 相似文献
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采用柠檬酸络合法制备了Co/CeO2及其钙掺杂系列催化剂,并对催化剂进行了低温N2物理吸附、X射线衍射、H2程序升温还原、傅里叶变换红外光谱、高分辨透射电镜表征以及乙醇水蒸气重整催化性能测试.结果表明,所制Co/CeO2催化剂具有良好的乙醇水蒸气重整催化性能,500oC时乙醇能全部转化为C1,氢气产率高达85%以上.Ca掺杂减小了载体CeO2纳米颗粒尺寸,但对还原后Co0尺寸的影响较小.当Ca掺杂量大于5.0%时,催化剂氧化还原性能和乙醇水蒸气重整催化性能下降.较高的还原温度有利于体相Ce4+还原为Ce3+,并且提高了催化活性,认为金属-氧化物边界的增加提高了催化活性.初步稳定性考察结果表明,5%钙掺杂后的催化剂具有更好的抗积炭性能. 相似文献
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用Nd:YAG激光器在2 mm厚的铝板上激发激光超声,通过激光反射镜偏转进行点阵扫描激励,用声发射传感器接收在铝板中传播的激光超声信号,通过信号放大和数据采集得到激光超声在铝板中传播的数据。对上述数据进行二维傅里叶变换得到了铝板中激光超声的模态分布和频率分布,接收到的激光超声是S0和A0两个模态多种频率的Lamb波。利用两个相同的探头对称地压紧在板的两个表面上,对两个探头接收到的信号进行相加和相减,可以将S0和A0模态分别提取出来。对单一模态的Lamb波再进行滤波,得到了窄频带单一模态的Lamb波。采用该方法实现了从杂乱的激光超声原始信号中提取出清晰的伤信号,并且得到了不同模态在不同频率范围的检测结果。 相似文献
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Ruiqi Bai 《Linear and Multilinear Algebra》2013,61(12):2540-2548