1—十二烷基氮杂环庚烷—2—酮的合成

已内酰胺与溴代十二烷在氢氧化钾的作用下，于甲苯中进行Ｎ－烷基化反应，合成了１－＋二烷基氮杂环庚烷－２－酮，收率８８％－９２％。     

CeO2/CdS heterojunction decorated cotton fabric as a recyclable photocatalyst for efficient light driven degradation of methylene blue

In this work, visible light response CeO₂/CdS decorated cotton fabrics as durable and facile recyclable composite photocatalysts were fabricated for photo-degradation of methylene blue (MB). First of all, amino-functionalized CeO₂/CdS heterojunctions were synthesized through a fast, efficient and low-cost co-precipitation method. Subsequently, the as-prepared CeO₂/CdS heterojunctions were immobilized on aldehyde-functionalized cotton fabric surfaces as composite photocatalysts via "amine-aldehyde" chemical reaction. The surface microstructure and chemical composition of the CeO₂/CdS decorated cotton fabric (CeO₂/CdS-CF) were characterized by SEM, FTIR and XPS, respectively. The results showed that CeO₂/CdS heterojunctions were successfully anchored and uniformly distributed on the surface of cotton fabric. Since the CeO₂/CdS heterostructure with efficient photo-generated charge transfer and separation, the as-prepared CeO₂/CdS-CF exhibited excellent photocatalytic activity, degrading MB under simulated sunlight irradiation with a degradation efficiency of 93.8% within 90 min. In addition, the degradation efficiency remained above 90.3% even after five successive degradation cycles, indicating the outstanding stability and recyclability of the obtained CeO₂/CdS-CF. This work opened up a facile preparation way for the fabrication of durable and recyclable composite photocatalysts, and has a promising application in treating dye contaminated wastewater.

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Properties of light-induced degradation and the electronic properties of nanocrystalline silicon solar cells grown under functionally graded hydrogen dilutions

The electronic properties of hydrogenated nanocrystalline silicon (nc-Si:H) were studied using drive-level capacitance profiling (DLCP) to obtain defect density profiles as well as transient photocapacitance (TPC) and transient photocurrent (TPI) spectroscopies to study the spectra of defect related optical transitions. These measurements were performed on a series of n–i–p solar cell devices with intrinsic layer thickness of roughly 1 μm. The nc-Si:H intrinsic layers were deposited using RF or MVHF glow discharge with various hydrogen dilution profiles predominantly on specular stainless steel substrates (SS/n⁺/i nc-Si:H/p⁺/ITO), but also on textured back reflectors (SS/Ag/ZnO/n⁺/i nc-Si:H/p⁺/ITO) in some cases. Crystallite fractions were estimated using Raman spectroscopy. The electronic properties determined by our measurements could be correlated with variations in structural device parameters and with the degree of hydrogen dilution profiling during growth. We also found, depending on the growth conditions, that the devices exhibited markedly different behaviors after prolonged light exposure (100 h using light at 610 nm and 500 mW/cm² intensity). We discuss one specific microscopic mechanism that may be responsible for the light-induced changes that we have observed.     

几种前缘流动控制的实验研究

在低速风洞中，以NACA0012翼型为例，采用对比实验的方法，研究了三种改善翼型大攻角气动性能的流动控制措施，即（1）在翼型上表面安装小三角翼涡发生器；（2）在翼型前缘安装矩形涡发生器；（3）利用前缘切口．实验雷诺数分别为4．9×105到6．5×105，攻角范围为-10°至20°．实验结果表明三种措施均可不同程度地改善原翼型在其失速区域的性能，不仅可以提高翼型的升力，而且可以提高其升阻比；但常用攻角范围内翼型气动性能有不同程度的下降，三种措施各有优缺点．几种前缘流动控制的实验研究@刘宝杰$北京航空航天大学404教研室!北京,1…     

质谱光电离/解离技术和生物分子结构鉴定

质谱是一种广泛应用于化学、生物医学、药学、环境、农业和能源等各领域的分子结构鉴定技术,这种技术通过准确测定分子离子和碎片离子的质量-电荷比来推导分子结构。如何将试样中待测组分有效气化、离子化,转变为具有不同质-荷比的气态离子是质谱仪器和分析方法研究的关键。基于不同物理化学原理的电离、解离方法各有特点,适合不同分析目的。常见的软电离技术一般产生稳定的偶电子离子,往往需要与其他技术联用才能实现分子离子的进一步解离。除了基于碰撞活化和电子得失的两类常见解离方法,光解离技术利用波长/能量可调控的光辐射来使样品分子电离,并引发特定化学键断裂。本文旨在综述不同电离/解离技术,重点探讨近年来发展的红外和紫外光电离/解离技术基本工作原理、仪器特点及其在生物分子(包括有机小分子、蛋白质、核酸和多糖等)结构鉴定中的应用。     

Chemical Diversity and Antimicrobial Potential of Cultivable Fungi from Deep-Sea Sediments of the Gulf of Mexico

A collection of 29 cultivable fungal strains isolated from deep-sea sediments of the Gulf of Mexico were cultivated under the “one strain, many compounds” approach to explore their chemical diversity and antimicrobial potential. From the 87 extracts tested, over 50% showed antimicrobial activity, and the most active ones were those from cultures grown at 4 °C in darkness for 60 days (resembling deep-sea temperature). PCA analysis of the LC-MS data of all the extracts confirmed that culture temperature is the primary factor in the variation of the 4462 metabolite features, accounting for 21.3% of the variation. The bioactivity-guided and conventional chemical studies of selected fungal strains allowed the identification of several active and specialized metabolites. Finally, metabolomics analysis by GNPS molecular networking and manual dereplication revealed the biosynthetic potential of these species to produce interesting chemistry. This work uncovers the chemical and biological study of marine-derived fungal strains from deep-sea sediments of the Gulf of Mexico.     

Vibrational Property of α-Borophene Determined by Tip-Enhanced Raman Spectroscopy

We report a Raman characterization of the α borophene polymorph by scanning tunneling microscopy combined with tip-enhanced Raman spectroscopy. A series of Raman peaks were discovered, which can be well related with the phonon modes calculated based on an asymmetric buckled α structure. The unusual enhancement of high-frequency Raman peaks in TERS spectra of α borophene is found and associated with its unique buckling when landed on the Ag(111) surface. Our paper demonstrates the advantages of TERS, namely high spatial resolution and selective enhancement rule, in studying the local vibrational properties of materials in nanoscale.