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191.
CongZhan Liu YiFei Zhang XuFang Li XueFeng Lu Zhi Chang ZhengWei Li AiMei Zhang YongJie Jin HuiMing Yu Zhao Zhang MinXue Fu YiBao Chen JianFeng Ji YuPeng Xu JingKang Deng RenCheng Shang GuoQing Liu FangJun Lu ShuangNan Zhang YongWei Dong TiPei Li Mei Wu YanGuo Li HuanYu Wang BoBing Wu YongJie Zhang Zhi Zhang ShaoLin Xiong Yuan Liu Shu Zhang HongWei Liu YiJung Yang Fan Zhang 《中国科学:物理学 力学 天文学(英文版)》2020,(4):20-34
The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments. 相似文献
192.
Study on the cationic modification and dyeing of ramie fiber 总被引:2,自引:0,他引:2
Zhao-Tie Liu Yani Yang Lili Zhang Zhong-Wen Liu Heping Xiong 《Cellulose (London, England)》2007,14(4):337-345
A modification procedure for ramie fiber using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) as a cationic
agent and NaOH as a catalyst was developed in this paper. The morphological and structural transformations of the fiber induced
by modification were determined by XRD (XRD), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA).
XRD results show that the crystal structure of the modified fiber was still preserved although its crystallinity was decreased,
which was confirmed from the TGA results. The mechanisms for the modification and dyeing of ramie fiber were analyzed, and
the optimum modification conditions were determined to be the CHPTAC concentration of 30 g L−1, the NaOH concentration of 15 g L−1, the reaction temperature of 50 °C, and the reaction time of 60 min. The raw and the modified fibers were dyed with C.I.
reactive red 2. The K/S values for the cationic modified fiber increased to be three times as high as the unmodified fiber. The dye uptakes increased
greatly with an increase in the nitrogen contents up to 0.4% on the modified fibers. 相似文献
193.
Xiaoliu Li Yongmei Wang Daming Du Zhong Wen Guoxiang Xiong Jiben Meng 《中国科学B辑(英文版)》1997,40(3):270-277
Solid state Michael addition reaction of indole with α, β-unsaturated carbonyl compounds was carried out, by which a series
of compounds containing three different heterocyclic groups binding to one carbon atom were ob-tained. In the presence of
Lewis acid, indole could undergo the solid state condensation reaction with aromatic ketones and aldehydes or quinones. The
solid state reaction showed higher selectivity and yield than solution reaction. The structures of products were identified
by IR,1H NMR, MS. elemental analysis and X-ray crystal analysis. The reac-tion mechanism was also proposed.
Project supported by the National Natural Science Foundation of China 相似文献
194.
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196.
Yongjin Fang Bu Yuan Guan Deyan Luan Xiong Wen Lou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7821-7825
Metal sulfides have received considerable attention for efficient sodium storage owing to their high capacity and decent redox reversibility. However, the poor rate capability and fast capacity decay greatly hinder their practical application in sodium‐ion batteries. Herein, an elegant multi‐step templating strategy has been developed to rationally synthesize hierarchical double‐shelled nanoboxes with the CoS2 nanosheet‐constructed outer shell supported on the CuS inner shell. Their structure and composition enable these hierarchical CuS@CoS2 nanoboxes to show boosted electrochemical properties with high capacity, outstanding rate capability, and long cycle life. 相似文献
197.
Zhenguang Wang Chuanchuan Zhang Henggang Wang Yuan Xiong Xinjian Yang Yu‐e Shi Andrey L. Rogach 《Angewandte Chemie (International ed. in English)》2020,59(25):9997-10002
Sulfur is not normally considered a light‐emitting material, even though there have been reports of a dim luminescence of this compound in the blue‐to‐green spectral region. Now, it is shown how to make red‐emissive sulfur by a two‐step oxidation approach using elemental sulfur and Na2S as starting materials, with a high photoluminescence quantum yield of 7.2 %. Polysulfide is formed first and is partially transformed into Na2S2O3 in the first step, and then turns back to elemental S in the second step. The elevated temperature and relatively oxygen‐deficient environment during the second step transforms Na2S2O3 into Na2SO3 incorporated with oxygen vacancies, thus resulting in the formation of a solid‐state powder consisting of elemental S embedded in Na2SO3. It shows aggregation‐induced emission properties, attributed to the influence of oxygen vacancies on the emission dynamics of sulfur by providing additional lower energy states that facilitate the radiative relaxation of excitons. 相似文献
198.
Zexi Liu Jing Ai Prashant Kumar Enming You Xiong Zhou Xi Liu Zhongqun Tian Petr Bou Yingying Duan Lu Han Nicholas A. Kotov Songyuan Ding Shunai Che 《Angewandte Chemie (International ed. in English)》2020,59(35):15226-15231
A surface‐enhanced Raman scattering‐chiral anisotropy (SERS‐ChA) effect is reported that combines chiral discrimination and surface Raman scattering enhancement on chiral nanostructured Au films (CNAFs) equipped in the normal Raman scattering Spectrometer. The CNAFs provided remarkably higher enhancement factors of Raman scattering (EFs) for particular enantiomers, and the SERS intensity was proportional to the enantiomeric excesses (ee) values. Except for molecules with mesomeric species, all of the tested enantiomers exhibited high SERS‐ChA asymmetry factors (g), ranging between 1.34 and 1.99 regardless of polarities, sizes, chromophores, concentrations and ee. The effect might be attributed to selective resonance coupling between the induced electric and magnetic dipoles associated with enantiomers and chiral plasmonic modes of CNAFs. 相似文献
199.
建立电感耦合等离子体原子发射光谱标准加入法测定铜精矿中Zn、Pb、As、Cu、Bi、MgO.分别对酸的加入种类和数量进行条件试验,采用盐酸–硝酸–盐酸–氢氟酸–高氯酸溶样,以标准加入法配制系列标准工作溶液,建立校正曲线,有效消除了样品基体对目标物检测结果的影响.目标物的分析谱线分别为Zn 206.2 nm,Pb 182.2 nm,As 197.2 nm,Cu 324.7 nm,Bi 190.2 nm,MgO 279.5 nm.各目标物校正曲线线性相关系数均不小于0.999,检出限为0.0002%~0.0006%,测定结果的相对标准偏差为0.62%~8.92%(n=6).按照该方法测定ZBK337、ZBK340铜精矿标准物质中Zn、Pb、As、Cu、Bi、MgO,测定值均在规定的标准值再现性限范围内. 相似文献
200.
Back Cover: Surface Polarization Matters: Enhancing the Hydrogen‐Evolution Reaction by Shrinking Pt Shells in Pt–Pd–Graphene Stack Structures (Angew. Chem. Int. Ed. 45/2014) 下载免费PDF全文