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991.
Yulin Wang Dr. Run Shi Dr. Lu Shang Prof. Geoffrey I. N. Waterhouse Jiaqi Zhao Prof. Qinghua Zhang Prof. Lin Gu Prof. Tierui Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):13157-13162
Carbon-supported NiII single-atom catalysts with a tetradentate Ni-N2O2 coordination formed by a Schiff base ligand-mediated pyrolysis strategy are presented. A NiII complex of the Schiff base ligand (R,R)-(−)-N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine was adsorbed onto a carbon black support, followed by pyrolysis of the modified carbon material at 300 °C in Ar. The Ni-N2O2/C catalyst showed excellent performance for the electrocatalytic reduction of O2 to H2O2 through a two-electron transfer process in alkaline conditions, with a H2O2 selectivity of 96 %. At a current density of 70 mA cm−2, a H2O2 production rate of 5.9 mol gcat.−1 h−1 was achieved using a three-phase flow cell, with good catalyst stability maintained over 8 h of testing. The Ni-N2O2/C catalyst could electrocatalytically reduce O2 in air to H2O2 at a high current density, still affording a high H2O2 selectivity (>90 %). A precise Ni-N2O2 coordination was key to the performance. 相似文献
992.
Junbo Gao Xingjie Zhang Kun Shang Weimao Zhong Ruihan Zhang Xiaochang Dai Xiaoli Li Qi Wang Yan Zou Weilie Xiao 《中国化学快报》2020,31(2):427-430
Callica rpabodinieri is a Chinese traditional medicine herb with anti-inflammatory activity in clinic.Herein,we report two new 9,10-seco and etherified abietane diterpenoids bodinieric acids J and K(1 and 2) and one known compound(3) isolated from the leaves and twigs of this plant.Their chemical structures were elucidated by detailed spectrometry data analysis and DP4+NMR calculation methods.Hypothetical biosynthetic pathways of 1-3 were preliminarily speculated.Compound 3 inhibited inflammasome activation and exhibited blockage of NLRP3 inflammasome activation at non-cytotoxic concentrations in vitro. 相似文献
993.
In this paper, we construct a new car-following model with inter-vehicle communication (IVC) to study the driving behavior under an accident. The numerical results show that the proposed model can qualitatively describe the effects of IVC on each vehicle’s speed, acceleration, movement trail, and headway under an accident and that the new model can overcome the full velocity difference (FVD) model’s shortcoming that collisions occur under an accident, which illustrates that the new model can better describe the driving behavior under an accident than the FVD model. 相似文献
994.
Xiaojun?ZhaoEmail author Pengjian?Shang Jingjing?Huang 《The European Physical Journal B - Condensed Matter and Complex Systems》2013,86(2):58
The paper mainly introduces a continuous detrended cross-correlation analysis method to detect the long-range fractal scaling behaviors of continuous and integrable functions. The effects of such method are tested by the generalized Weierstrass function with various seeds. It presents accurate scaling characterization as desired by comparing with that from the popular detrended cross-correlation analysis method of discrete case. 相似文献
995.
We have examined the commonly used Brenner potentials in the context of the thermodynamic properties of diamond. A simple optimized Brenner potential is proposed that provides very good predictions of the thermodynamic properties of diamond. It is shown that, compared to the experimental data, the lattice wave theory of molecular dynamics (LWT) with this optimized Brenner potential can accurately predict the temperature dependence of specific heat, lattice constant, Grüneisen parameters and coefficient of thermal expansion (CTE) of diamond. 相似文献
996.
Thermal contact resistance plays a very important role in heat transfer efficiency and thermomechanical coupling response between two materials, and a common method to reduce the thermal contact resistance is to fill a soft interface material between these two materials. A testing system of high temperature thermal contact resistance based on INSTRON 8874 is established in the present paper, which can achieve 600°C at the interface. Based on this system, the thermal contact resistance between superalloy GH600 material and three-dimensional braid C/C composite material is experimentally investigated, under different interface pressures, interface roughnesses and temperatures, respectively. At the same time, the mechanism of reducing the thermal contact resistance with carbon fiber sheet as interface material is experimentally investigated. Results show that the present testing system is feasible in the experimental research of high temperature thermal contact resistance. 相似文献
997.
A highly efficient and convenient method for the synthesis of 1,2,4,5-tetrasubstituted imidazoles from readily accessible 2-azido acrylates and nitrones has been developed. This reaction proceeded under mild conditions without the assistance of any metal, acid, or base. 相似文献
998.
A new aristololactam, 5-methoxyaristololactam I (1), was isolated from an ethanol extract of the whole plant of Asarum ichangense C. Y. Cheng et C. S. Yang, together with twenty known compounds (2-21). The structure of 1 was elucidated by spectroscopic methods. Compounds 11, 13, 17, and 19 were isolated from Aristolochiaceae for the first time. Compounds 2, 14, and 15 are considered as common constituents of the genus Asarum. 相似文献
999.
在pH 1.81的B-R缓冲介质中,由十二烷基磺酸钠(SDBS)与奎尼丁的相互反应导致其分别在278.0,377.0 nm两波长处所测得的共振散射信号(I)大大增强。当SDBS的浓度为3.0×10~(-4)mol·L~(-1)时,分别在上述两波长处测得的共振散射强度值(I_(278.0)及I_(377.0))与相应的奎尼丁浓度依次在0.067~40,0.062~40μmol·L~(-1)范围内呈线性关系,其检出限(3σ)分别为6.71,6.15nmol·L~(-1)。据此可作奎尼丁的单波长法共振散射光谱测定。进一步研究发现:如采用分别在240.0nm(波谷)及275.0nm(波峰)测得的共振散射强度的比率(即I_(240.0)/I_(375.0))作为参数,则其与奎尼丁浓度在0.007~75μmol·L~(-1)范围内呈线性关系,且奎尼丁检出限(3σ)为0.691nmol·L~(-1)。由此可见,采用双波长测量技术的共振散射比率法测定奎尼丁的效果优于前者。 相似文献
1000.
Gui‐Ling Zhang Hong‐Liang Yuan Hui Zhang Yan Shang Miao Sun 《International journal of quantum chemistry》2011,111(15):4214-4223
The electron transport properties of a novel p‐n junction nanowire caused by boron‐doping and phosphorus‐doping are investigated using density functional theory combined with the nonequilibrium Green's functions formalism. A satisfying rectification is observed. This is a reasonable result after the analysis of the molecular‐projected self‐consistent Hamitonian (MPSH) states, transmission spectra, the frontier orbitals, and the dipole moments. In contrast, the undoped chain has no rectification character. In addition, a negative differential resistance behavior is also observed at V = 1.8 ~ 2.2 V in the doped nanowire and it could be illustrated from the MPSH states and the transmission spectra. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献