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Intermolecular reductive coupling of aliphatic ketones with alkynes and alkenes by BCN photocatalysts

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Science China Chemistry 2025年第1期 181-185页

作者： Yanping Xia Luyang Sun Jiajia Cheng Sibo Wang Meifang zheng Xinchen Wang State Key Laboratory of Photocatalysis on Energy and Environment College of Chemistry Fuzhou University

A photocatalytic process was developed for intermolecular reductive coupling of aliphatic ketones with alkynes/alkenes to furnish tertiary alcohols. Mechanistic studies support that boron carbonitrides(BCN) promote the single electron reduction of unactivated aliphatic ketones to generate ketyl radicals with visible light irradiation, which then react with alkynes and alkenes to afford the allylic and aliphatic alcohols, respectively. The heterogeneous photocatalytic system is compatible with diverse substrates including pharmaceutical-related molecules(43 examples) with reusability and scale-up experiments, verifying the complementary synthetic utility of this method to the homogeneous catalysts.

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Ta-doped modified Gd2O3 film for a novel high k gate dielectric

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Journal of Materials Science & Technology 2019年第10期35卷 2305-2311页

作者： Shuan Li Yanqing Wu Guoling Li Hongen Yu kai fu Yong Wu Jie zheng Wenhuai Tian Xingguo Li Department of Materials Physics and Chemistry University of Science and Technology BeijingBeijing 100083China Beijing National Laboratory of Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China College of Materials Science and Engineering Qingdao UniversityQingdao 266071China

Gadolinium oxide(Gd2O3) film has potential as a candidate gate dielectric to replace Hf O2. In this work,we provide a simple method by trace Ta(~1%) doping to significantly improve the dielectric properties of Gd2O3 film. And effects of annealing temperatures of Ta-doped Gd2O3(GTO) films are investigated in detail. Results show that GTO film annealed at 500℃ exhibits excellent performance as a novel gate dielectric material for integrated circuit, showing a small surface roughness of 0.199 nm, a large band gap of 5.45 e V, a high dielectric constant(k) of 21.2 and a low leakage current density(Jg) of 2.10 × 10^-3A/cm^*** properties of GTO films are superior to pure Gd2O3 films and these GTO films meet the requirements for next-generation gate dielectrics. In addition, impedance spectrum is first used to analyze the equivalent circuit of GTO based metal-oxide-semiconductor(MOS) capacitors, which represents a new insight to understand observed electrical behaviors.

关键词： Rare earth oxides High k film Magnetron sputtering Annealing temperature Gate dielectrics

An Example of Embedded Singular Continuous Spectrum for Discrete Schrödinger Operators

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1837-1849页

作者： zheng Qi fu Xiong LI Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

We present an example of a potential such that the corresponding discrete Schrödinger operator has singular continuous spectrum embedded in the absolutely continuous spectrum.

关键词： Sparse potentials singular continuous spectrum Prüfer variables

Special Focus on Millimeter Wave Communications Techniques and Devices for 5G—Editorial

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Science China(Information Sciences) 2017年第8期60卷 5-6页

作者： fu-Chun zheng Gang WU Harbin Institute of Technology The University of York University of Electronic Science and Technology of China

Due to the rapid development of cost-effective CMOS solutions and recent experimental validation on communications over millimeter wave(mm Wave)bands,which span from 30 to 300 GHz,mm Wave communications technologies are being considered for 5G mobile systems to provide ultra-high data rates for front haul,back haul,and short or middle range broadband *** to the array gain of massive multiple-input multiple-output(m-MIMO)antenna arrays,the heavy path loss of mmWave

关键词： Wave for Editorial Special Focus on Millimeter Wave Communications Techniques and Devices for 5G MIMO on

Approaching Quantum-Limited Amplification with Large Gain Catalyzed by Optical Parametric Amplifier Medium

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Communications in Theoretical Physics 2017年第7期67卷 76-82页

作者： Qiang zheng kai Li School of Mathematics Guizhou Normal University Guiyang 550025 China Beijing Computational Science Research Center Beijing 100193 China

Amplifier is at the heart of experiments carrying out the precise measurement of a weak signal. An idea quantum amplifier should have a large gain and minimum added noise simultaneously. Here, we consider the quantum measurement properties of the cavity with the OPA medium in the op-amp mode to amplify an input signal. We show that our nonlinear-cavity quantum amplifier has large gain in the single-value stable regime and achieves quantum limit unconditionally.

关键词： amplifier op-amp mode OPA quantum limit

Preliminary investigation into feasibility of dissolved methane measurement using cavity ringdown spectroscopy technique

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Frontiers of physics 2016年第6期11卷 159-166页

作者： Zhen-Nan Wang Wang-Quan Ye Xiao-Ning Luan fu-Jun Qi kai Cheng Ronger zheng Optics and Optoelectronies Laboratory Ocean University of China Qingdao 266100 China

For the exploration of gas hydrate resources by measuring the dissolved methane concentration in seawater, a continuous-wave cavity ringdown spectroscopy (CW-CRDS) experimental setup was constructed for trace methane detection. A current-modulation method, rather than a cavity-modulation method using an optical switch and a piezoelectric transducer, was employed to realize the cavity excitation and shutoff. Such a current-modulation method enabled the improvement of the experimental setup construction and stability, and the system size and stability are critical for a sensor to be deployed underwater. Ringdown data acquisition and processing were performed, followed by an evaluation of the experimental setup stability and sensitivity. The obtained results demonstrate that great errors are introduced when a large fitting window is selected if the analog-to-digital converter has an insufficient resolution. The ringdown spectrum of methane corresponding to the 2 nu(3) band R(4) branch was captured, and the methane concentration in lab air was determined to be 2.06 ppm. further experiments for evaluating the quantitative ability of this CW-CRDS experimental setup are underway from which a high-sensitivity methane sensor that can be combined with a degassing system is expected.

关键词： gas hydrate methane continuous-wave cavity ringdown spectroscopy current-modulation method

一株同步硝化反硝化菌株的筛选及其生物电化学脱氮性能研究

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南京农业大学学报 2025年第1期48卷 133-143页

作者：田瑞瑞付欢郑云黄新琦周俊雍晓雨南京工业大学生物与制药工程学院江苏南京211816 南京师范大学地理科学学院江苏南京210023

[目的]本文旨在获得具有高效脱氮性能的异养硝化-好氧反硝化(heterotrophic nitrification-aerobic denitrification,HN-AD)功能菌株,构建生物电化学-同步硝化反硝化(bio-electrochemical systems-simultaneous nitrification and denitrification,BES-SND)耦合系统,实现脱氮效率的提升。[方法]从活性污泥中筛选HN-AD菌株,鉴定后通过摇瓶试验分析其脱氮性能。然后进一步研究碳源、C/N、溶解氧等外界因素对菌株同步硝化反硝化性能的影响。将菌株接种到微生物燃料电池(microbial fuel cells,MFC)的生物阴极,分析低C/N条件下BES-SND体系的脱氮性能。[结果]从活性污泥中筛选出一株具有同步硝化反硝化性能的HN-AD菌株,命名为Alcaligenes aquatilis N3。确定该菌株发生SND反应的最适碳源为乙酸钠、C/N值为20、溶解氧为3.70 mg·L^(-1)。在BES-SND脱氮体系中,C/N值分别为2、4、6、8时,菌株*** N3的总氮去除率分别为20.51%、26.67%、37.76%和48.50%。在C/N=2的试验条件下,BES-SND系统的总氮去除速率在第5天仍为1.79 mg·L^(-1)·d^(-1)。[结论]在低碳环境下,*** N3菌株依然可以在BES-SND耦合脱氮体系中实现脱氮,降低了脱氮过程对碳源的依赖性,具有一定的实际环境应用潜力。

关键词：同步硝化反硝化异养硝化-好氧反硝化生物电化学低C/N值微生物燃料电池

Determination of H^+ diffusion coefficient in the course of H^+ response of a W/WO_3 pH electrode

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Rare Metals 2005年第4期24卷 351-357页

作者： CHEN Dongchu fu Zhaoyang zheng Jiashen College of Mechanical Engineering South China University of Technology Guangzhou 510640 China School of Science Foshan University Foshan 528000 China Chemistry Department Huazhong University of Science and Technology Wuhan 430074 China

A WAVO3 pH electrode was prepared by a method of sol-gel. In order to study the H^＋ response dynamic mechanism, the electrochemical impedance spectroscopy （EIS） experiment was conducted. It was found that the H^＋ response course is controlled by the H^＋ diffusion from the solution to the WO3 film, based on the analysis of EIS spectra. The EIS and potential step method were used to determinate the H＋ diffusion coefficient （D） in the course of H^＋ response of this WAVO3 electrode, and the values of D calculated by these two method correspond very well, which all are about 10^-19cm^2/s The imposed different potential steps make little effect on the calculation of H^＋ diffusion coefficient, and it was found that the limiting Cottrell equation of short elapsed time fits well to the current transient caused by a potential step, based on the analysis of the time constant.

关键词： pH electrode diffusion coefficient dynamic mechanism tungsten oxide sol-gel

Engineering Research Progress of Electrochemical Microreaction Technology—A Novel Method for Electrosynthesis of Organic Chemicals

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Engineering 2021年第1期7卷 22-32页

作者： Siyuan zheng Junyu Yan kai Wang State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Electrochemical methods are environmentally friendly and have unique advantages in the synthesis of organic ***,their implementation is limited due to the complex transport problems posed by traditional electrochemical ***,the application of microreaction technology in electrosynthesis studies has reduced the transport distance of ions and increased the specific surface area of electrodes,leading to efficient,successive,and easily scaled-up electrosynthesis *** this review article,engineering advantages of using microchannels in electrosynthesis are discussed from process enhancement *** patterns and mass transfer behaviors in recently reported electrochemical microreactors are analyzed,and prototypes for the reactor scale-up are *** a relatively new research area,many scientific rules and engineering features of electrosynthesis in microreactors require *** research foci,considered crucial for the development of novel electrosynthesis technology,are therefore proposed.

关键词： synthesis Electrochemical successive