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391.
392.
The cyanohydrin trimethylsilyl ether of o-chlorobenzoylferrocene has been synthesized by the addition of trimethylsilyl cyanide (TMSCN) in methylene chloride in the presence of zinc iodide. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic, space group P21/n with the following crystallographic parameters: a = 9.480(3) ?, b = 22.319(6) ?, c = 9.783(3) ?, β = 101.197(4)°, μ = 0.943 mm − 1, V=2030.5(10) ?3, Z=4, F(0 0 0) = 880, D
calc=1.386 mg/m3, T=293(2) K, 1.82° ≤ θ ≤ 26.40°, the final R factor: R
1=0.0366, wR
2=0.0802. 相似文献
393.
唐代陆羽撰写的《茶经》被誉为“茶叶百科全书”,是中国乃至世界上最早关于茶文化的史料,也是保留最完整、最全面的茶学专著。通过探析《茶经》中蕴含的育人价值,挖掘《茶经》中的化学课程资源。在化学教学中,将《茶经》中与化学知识契合的传统文化内容作为情境载体建立学习桥梁,从化学角度对传统文化内容进行再认识,从文化视角感受化学中蕴含的人文底蕴,帮助学习和理解化学知识,增强文化认同感和民族自豪感。依据新课标中的情境素材建议与要求,梳理了《茶经》中可与高中化学教科书相联系的内容,为创设真实的情境提供素材,利用古代茶器具与中学化学实验仪器之间的相似性创设情境。并且提出了关于中学化学教学中有效融入传统文化的几点建议。 相似文献
394.
Xinyao Wang Dr. Xiaowei Yang Chen Zhao Yutong Pi Prof. Xiaobo Li Prof. Zhongfan Jia Prof. Si Zhou Prof. Jijun Zhao Prof. Limin Wu Prof. Jian Liu 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302829
Rational design of polymer structures at the molecular level promotes the iteration of high-performance photocatalyst for sustainable photocatalytic hydrogen peroxide (H2O2) production from oxygen and water, which also lays the basis for revealing the reaction mechanism. Here we report a benzoxazine-based m-aminophenol-formaldehyde resin (APFac) polymerized at ambient conditions, exhibiting superior H2O2 yield and long-term stability to most polymeric photocatalysts. Benzoxazine structure was identified as the crucial photocatalytic active segment in APFac. Favorable adsorption of oxygen/intermediates on benzoxazine structure and commendable product selectivity accelerated the reaction kinetically in stepwise single-electron oxygen reduction reaction. The proposed benzoxazine-based phenolic resin provides the possibility of production in batches and industrial application, and sheds light on the de novo design and analysis of metal-free polymeric photocatalysts. 相似文献
395.
Yutong Pi Linxia Cui Prof. Wenhao Luo Dr. Haitao Li Dr. Yanfu Ma Dr. Na Ta Xinyao Wang Prof. Rui Gao Prof. Dan Wang Prof. Qihua Yang Prof. Jian Liu 《Angewandte Chemie (International ed. in English)》2023,62(43):e202307096
Mimicking the structures and functions of cells to create artificial organelles has spurred the development of efficient strategies for production of hollow nanoreactors with biomimetic catalytic functions. However, such structure are challenging to fabricate and are thus rarely reported. We report the design of hollow nanoreactors with hollow multishelled structure (HoMS) and spatially loaded metal nanoparticles. Starting from a molecular-level design strategy, well-defined hollow multishelled structure phenolic resins (HoMS-PR) and carbon (HoMS-C) submicron particles were accurately constructed. HoMS-C serves as an excellent, versatile platform, owing to its tunable properties with tailored functional sites for achieving precise spatial location of metal nanoparticles, internally encapsulated (Pd@HoMS-C) or externally supported (Pd/HoMS-C). Impressively, the combination of the delicate nanoarchitecture and spatially loaded metal nanoparticles endow the pair of nanoreactors with size–shape-selective molecular recognition properties in catalytic semihydrogenation, including high activity and selectivity of Pd@HoMS-C for small aliphatic substrates and Pd/HoMS-C for large aromatic substrates. Theoretical calculations provide insight into the pair of nanoreactors with distinct behaviors due to the differences in energy barrier of substrate adsorption. This work provides guidance on the rational design and accurate construction of hollow nanoreactors with precisely located active sites and a finely modulated microenvironment by mimicking the functions of cells. 相似文献
396.
Zhang JianBin Zhang Tong Ma Kai Chen GuoHua Zhang DongYan Wei XiongHui 《中国科学B辑(英文版)》2008,51(2):158-165
A desulfurization strain that belongs to the thermophilic alkaline desulphuricant is designated as strain GDJ-3 and isolated from Inner Mongolia, China. The colony of the strain shows tiny, yellow, or white-yellow, and it becomes henna
with the protracting of cultivated time. The cells are bacilliform (0.3−0.6 × 1.0−1.2 μm), motive, and Gram negative. The
strain GDJ-3 is able to utilize respectively the thiosulphate, sulfate, sulfite, or sulfide as sulfur source, utilize the carbon dioxide
as the carbon source, and utilize the ammonium or nitrate as the nitrogen source. According to GenBank data, 16s RNA results
of GDJ-3 are in good agreement with Alpha proteobacterrium sp. (97%) and Ochrobactrum sp. (98%). For GDJ-3, the optimum growth temperature is at 45°C, the optimum pH is at 8.5–8.8, and the optimum rocking speed of sorting table
is at 150 r/min. Under the optimum culture condition, the cells of the strain can live for about 18 h. In the desulfurization
solution, which is prepared according to the composition of DDS solution, the objectionable constituents of sodium thiosulphate
and sodium sulfide were added factitiously, and the bacterial cell concentration was set at 107/mL. After the regeneration of the above desulfurization solution by the strain cells, the concentration of sodium thiosulphate
was decreased by 14.75 g/L (percentage loss of content 13.21%), the concentration of sodium sulfide was decreased by 0.76
g/L (percentage loss of content 87.36%) in the desulfurization solution in 9.5 hours, and sulfur appeared. Maybe, this kind
of strain can be used as the regeneration’s bacterial source of DDS solution. 相似文献
397.
Dr. Yang Wei Dr. Yue Pan Dr. Enlong Zhou Dr. Ze Yuan Dr. Hao Song Dr. Yilin Wang Dr. Jie Zhou Jiahui Rui Mengjiao Xu Prof. Lixin Ning Dr. Zhanning Liu Dr. Hongyu Wang Prof. Xiaoji Xie Prof. Xiaobin Tang Prof. Haiquan Su Xianran Xing Prof. Ling Huang 《Angewandte Chemie (International ed. in English)》2023,62(27):e202303482
Although large amount of effort has been invested in combating thermal quenching that severely degrades the performance of luminescent materials particularly at high temperatures, not much affirmative progress has been realized. Herein, we demonstrate that the Frenkel defect formed via controlled annealing of Sc2(WO4)3:Ln (Ln=Yb, Er, Eu, Tb, Sm), can work as energy reservoir and back-transfer the stored excitation energy to Ln3+ upon heating. Therefore, except routine anti-thermal quenching, thermally enhanced 415-fold downshifting and 405-fold upconversion luminescence are even obtained in Sc2(WO4)3:Yb/Er, which has set a record of both the Yb3+-Er3+ energy transfer efficiency (>85 %) and the working temperature at 500 and 1073 K, respectively. Moreover, this design strategy is extendable to other hosts possessing Frenkel defect, and modulation of which directly determines whether enhanced or decreased luminescence can be obtained. This discovery has paved new avenues to reliable generation of high-temperature luminescence. 相似文献
398.
Mei Li Zhaogang Liu Yanhong Hu Zhenxue Shi 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,320(1-3):78-84
In this work large CeO2 particles were prepared using H2C2O4 and NH4HCO3 as precipitators. The effects of feeding mode and speed, stirring speed, aging time, precipitate and calcination temperature and precipitation method on physicochemical properties of CeO2 were studied when the precipitator was H2C2O4. By the NH4HCO3 precipitation method, the effects of adding inoculating crystals and additives on particle size, loose density and fluidity of CeO2 were investigated. Under optimized conditions, large CeO2 particles with high loose density and good fluidity of can be prepared by either H2C2O4 or NH4HCO3 precipitation method. SEM also investigates the morphology of the particles prepared by both methods. The results show that physicochemical properties of CeO2 particles prepared by the NH4HCO3 precipitation method are not as good as those of CeO2 particles prepared by the H2C2O4 precipitation method. However, both methods are suitable for industrial production due to their simple processes, low equipment investment and ease for industrial development. Our results show that large rare earth particle can be prepared by the optimized conventional methods. This study provided a useful method to prepare of large rare earth particles. 相似文献
399.
Wei?Xiao Jing-Lin?XiaoEmail author 《International Journal of Theoretical Physics》2016,55(6):2936-2941
We study the effects of the temperature and electric field on the coherence time of a RbCl parabolic quantum dot (PQD) qubit by using the variational method of Pekar type, the Fermi Golden Rule and the quantum statistics theory (VMPTFGRQST). The ground and the first excited states’ (GFES) eigenenergies and the eigenfunctions of an electron in the RbCl PQD with an applied electric field are derived. A single qubit can be realized in this two-level quantum system. It turns out that the coherence time is a decreasing function of the temperature and the electric field, whereas it is an increasing one of the effective confinement length (ECL). By changing the electric field, the temperature and the ECL one can adjust the coherence time. Our research results may be useful for the design and implementation of solid-state quantum computation. 相似文献
400.
采用基于密度泛函理论的第一原理计算方法,我们研究了Cu(111)表面上石墨烯成核生长过程中CxHy小团簇的吸附和生成行为. 计算结果表明:随着氢原子饱和度、氢原子个数的增大,CxHy团簇的形成能减小,碳原子与铜表面的平均距离增加,C-C键的平均键长呈增大趋势. 然而,当生成的CxHy团簇具有空间对称结构时,在一定程度上打破了上述规律性. 令人惊奇的是,形成的C3H4和C3H5对称团簇具有类似石墨烯的空间结构,这类结构可能在石墨烯的形成过程中起着重要的作用. 相似文献