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991.
Tetradecacobalt(II)‐Containing 36‐Niobate [Co14(OH)16(H2O)8Nb36O106]20− and Its Photocatalytic H2 Evolution Activity 下载免费PDF全文
Prof. Jingyang Niu Fang Li Dr. Junwei Zhao Pengtao Ma Dr. Dongdi Zhang Dr. Bassem Bassil Prof. Ulrich Kortz Prof. Jingping Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9852-9857
A gigantic Co14‐containing 36‐niobate, Na12K8[Co14(OH)16(H2O)8Nb36O106] ? 71H2O ( 1 ), has been prepared by the hydrothermal method and structurally characterized. Polyanion [Co14(OH)16(H2O)8Nb36O106]20? ( 1 a ) comprises a central Co7 core, surrounded by another seven isolated Co2+ ions and six Lindqvist‐type (Nb6O19) hexaniobate fragments. This is the first example of a high‐nuclear cobalt‐cluster‐containing polyoxoniobate. The photocatalytic H2 evolution activity of Pt‐loaded 1 was observed in methanol solution under irradiation using a 300 W Xe lamp. 相似文献
992.
993.
本文设计了一种基于超材料的偏振不敏感太赫兹宽带吸波体.吸波体包含两层金属和一层中间介质,表面金属层每一个周期单元由五种尺寸接近的金属块按照相邻不同的规律排列成5×5的方形阵列.各种尺寸金属块分别产生单峰谐振吸收,五个谐振吸收峰相互靠近从而产生宽带吸收.通过研究吸波体表面电流和电场z分量分布情况可知,入射太赫兹能量的吸收主要是由y方向上电场引起的电偶极子振荡和z方向上磁场引起的磁极化产生,而且金属层的欧姆损耗起主要作用.仿真结果表明,吸波体吸收率在80%以上的带宽约为1.2 THz,最高吸收率可达98.7%,半峰全宽(FWHM)为1.6 THz,该宽带吸波体的厚度约为中心波长的二十分之一,对偏振方向不敏感,且能实现大角度吸收,在太赫兹频段的电磁隐身、测辐射热探测器以及宽带通信等领域有潜在的应用价值. 相似文献
994.
995.
Rong J Lee LA Li K Harp B Mello CM Niu Z Wang Q 《Chemical communications (Cambridge, England)》2008,(41):5185-5187
Fibrillar M13 bacteriophages were used as basic building blocks to generate thin films with aligned nanogrooves, which, upon chemical grafting with RGD peptides, guide cell alignment and orient the cell outgrowth along defined directions. 相似文献
996.
Xihui Ouyang Wei Zhang Jun Xu Na Chang Canping Pan Jingping Zhang Weimin Niu 《Journal of Analytical Chemistry》2009,64(9):935-940
A method has been developed for confirmation and quantitation of ten sulfonylurea herbicides (nicosufuron, thifensulfuron-methyl,
metsulfuron-methyl, sulfometuron-methyl, chlorsulfuron, ethametsulfuron-methyl, tribenuron, bensulfuron-methyl, pyrazosulfuron-ethyl
and chlorimuron-ethyl) in water samples. Herbicides were extracted from water by off-line solid-phase extraction (SPE). Different
types of absorbents were evaluated: silica-based ODS-C18 and two polymeric sorbents, Cleanert HXN and Oasis HLB. Analyte determination and quantitation was performed by liquid chromatography
with electrospray mass spectrometry (LC-ESI-MS) instrumentation, equipped with ion trap mass filter. Confirmatory analysis was carried out by LC/MS/MS. MS data acquisition
was performed by a single or two-ion extracted ion monitoring program. The ten herbicides were measured in fortified tap water.
Average recoveries of the nine analytes (except for tribenuron) from water samples were in the range of 77–109%, and the RSD
ranged from 0.3 to 14.5%. The limit of detections (LODs) varied from 6 to 34.8 ng/L. 相似文献
997.
对用分光计测定光栅常数为1/300 mm透射光栅1级角色散的方法进行了改进,给出了引入自组光具组进行测量的方法.改进后的方法充分利用自组光具组基本特性参数在较大范围内连续可调的优点,克服传统的用分光计测量方法中光路的关键参数不可调节的不足,从而提高了测量精度.自组光具组的引入,也起到使光路参数选取具有多样性和丰富光路调... 相似文献
998.
999.
Control of Switching Modes and Conductance Quantization in Oxygen Engineered HfOx based Memristive Devices 下载免费PDF全文
Sankaramangalam Ulhas Sharath Stefan Vogel Leopoldo Molina‐Luna Erwin Hildebrandt Christian Wenger Jose Kurian Michael Duerrschnabel Tore Niermann Gang Niu Pauline Calka Michael Lehmann Hans‐Joachim Kleebe Thomas Schroeder Lambert Alff 《Advanced functional materials》2017,27(32)
Hafnium oxide (HfOx)‐based memristive devices have tremendous potential as nonvolatile resistive random access memory (RRAM) and in neuromorphic electronics. Despite its seemingly simple two‐terminal structure, a myriad of RRAM devices reported in the rapidly growing literature exhibit rather complex resistive switching behaviors. Using Pt/HfOx/TiN‐based metal–insulator–metal structures as model systems, it is shown that a well‐controlled oxygen stoichiometry governs the filament formation and the occurrence of multiple switching modes. The oxygen vacancy concentration is found to be the key factor in manipulating the balance between electric field and Joule heating during formation, rupture (reset), and reformation (set) of the conductive filaments in the dielectric. In addition, the engineering of oxygen vacancies stabilizes atomic size filament constrictions exhibiting integer and half‐integer conductance quantization at room temperature during set and reset. Identifying the materials conditions of different switching modes and conductance quantization contributes to a unified switching model correlating structural and functional properties of RRAM materials. The possibility to engineer the oxygen stoichiometry in HfOx will allow creating quantum point contacts with multiple conductance quanta as a first step toward multilevel memristive quantum devices. 相似文献
1000.