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Current oscillations during the electrochemical oxidation of sulfide in the presence of an external resistor

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Science China Chemistry 2008年第4期51卷 333-340页

作者： feng jiamin GAO QingYu LI Jun LIU Li MAO ShanCheng College of Chemical Engineering China University of Mining and TechnologyXuzhou 221008China

The electrochemical oxidation of sulfide on a polycrystalline platinum electrode was studied under potentiostatic condition when an external resistor is in series with the working electrode. Only two os- cillatory regions can be obtained in the absence of the external resistance, but four oscillatory regions, including two new current oscillations, were found in this system by controlling the external resistance. It is demonstrated that three oscillatory regimes, which arise on the positive branch of current-potential curve, can be classified as HN-NDR (Hidden N-shaped Negative Differential Resistance) oscillators. For the first oscillatory region, various transient complex phenomena, which result from the change of the electrode/electrolyte interface by accumulation of adsorbed element sulfur on the electrode, have been observed. The dynamic behavior of NDR (Negative Differential Resistance) oscillations, appearing along with negative branch of polarization curve, can transform from oscillations into bistability with a sufficient large external resistance in series. Two oscillatory regions in high-potential region classified as HN-NDR type oscillations are separated by a saddle-loop bifurcation. They displayed a sequence of bursting oscillations and irregular oscillations, respectively. The electrochemical oxidation of sulfide provides a model system for studying complex dynamics and possible application in sulfur removal.

关键词： sulfide electrochemical oxidation series resistance bistability and oscillations mixed-mode and bursting oscillations

Period-doubling and chaotic oscillations in the ferroin-catalyzed Belousov-Zhabotinsky reaction in a CSTR

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Science China Chemistry 2007年第2期50卷 205-211页

作者： ZONG ChunYan GAO QingYu WANG YuMei feng jiamin MAO ShanCheng ZHANG Lu School of Chemical Engineering China University of Mining and TechnologyXuzhou 221008China

The ferroin-catalyzed Belousov-Zhabotinsky(BZ) reaction,the oxidation of malonic acid by acidic bromate,is the most commonly investigated chemical system for understanding spatial pattern forma-tion. Various oscillatory behaviors were found from such as mixed-mode and simple period-doubling oscillations and chaos on both Pt electrode and Br-ISE at high flow rates to mixed-mode oscillations on Br-ISE only at low flow rates. The complex dynamic behaviors were qualitatively reproduced with a two-cycle coupling model proposed initially by Gy?rgyi and Field. This investigation offered a proper medium for studying pattern formation under complex temporal dynamics. In addition,it also shows that complex oscillations and chaos in the BZ reaction can be extended to other bromate-driven nonlinear reaction systems with different metal catalysts.

关键词： Belousov-Zhabotinsky reaction period-doubling oscillations numerical simulation

Kinetic study on hydrolysis and oxidation of formamidine disulfide in acidic solutions

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Science China Chemistry 2012年第2期55卷 235-241页

作者： HU Ying feng jiamin LI YanWei SUN YanYan XU Li ZHAO YueMin GAO QingYu College of Chemical Engineering China University of Mining and Technology Xuzhou 221008 China

Hydrolysis and oxidation of formamidine disulfide in acidic medium were investigated using high-performance liquid chro- matography （HPLC） and mass spectrometry （MS） at 25 ~C. By controlling the slow reaction rate and choosing appropriate mobile phase, HPLC provides the unique advantages over other methods （UV-Vis, chemical separation） in species tracking and kinetic study. In addition to thiourea and formamidine sulfinic acid, two unreported products were also detected in the hy- drolysis reaction. Mass spectrometry measurement indicates these two products to be formamidine sulfenic acid and thiocyan- ogen with mass weights of 92.28 and 116,36, respectively. In the oxidation of formamidine disulfide by hydrogen peroxide, besides thiourea, formamidine sulfenic acid, formamidine sulfinic acid, thiocyanogen and urea, formamidine sulfonic acid and sulfate could be detected. The oxidation reaction was found to be first order in both forrnamidine disulfide and hydrogen per- oxide. The rate constants of hydrolysis and oxidation reactions were determined in the pH range of 1.5-3.0. It was found both rate constants are increased with the increasing of pH. Experimental curves of different species can be effectively simulated via a mechanism scheme for formamidine disulfide oxidation, including hydrolysis equilibrium of formamidine disulfide and irre- versible hydrolysis of formamidine sulfenic acid.

关键词： formamidine disulfide hydrolysis oxidation HPLC-MS

CdS Quantum Dots-sensitized TiO_2 Nanotube Arrays for Solar Cells

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Journal of Wuhan University of Technology(Materials Science) 2013年第1期28卷 17-21页

作者：隋小涛 TAO Haizheng LOU Xianchun WANG Xuelai feng jiamin ZENG Tao 赵修建 State Key Laboratory of Silicate Materials for Architectures (Wuhan University of Technology)

CdS quantum dots（QDs） sensitized TiO2 nanotube arrays photoelectrodes were investigated for their photovoltaic performance of quantum dots-sensitized solar cells. The highly ordered TiO2 nanotube arrays（TNAs） were synthesized on Ti foils by anodic oxidation method. Then CdS quantum dots were deposited onto the TiO2 nanotube arrays by successive ionic layer absorption and reaction（SILAR） method to serve as the sensitizers. Cd（NO3）2 and Na2S were used as the precursor materials of Cd＋ and S2- ions, respectively. It is found that the CdS QDs sensitizer may significantly increase the light response of TiO2 nanotube arrays. With increasing CdS QDs deposition cycles, the visible light response increases. Maximum photocurrent was obtained for the QDs that have an absorption peak at about 500 nm. Under AM 1.5 G illuminations（100 mW cm^-2）, a 4.85 mA/cm^2 short circuit current density was achieved, and the maximium energy conversion efficiency of the asprepared CdS QDs-sensitized TNAs solar cells was obtained as high as 0.81% at five SILAR cycles.

关键词： quantum dots sensitized solar cell successive ionic layer adsorption and reaction TiO2 vnanotube arrays

Bistachybotrysins D and E,one stereoisomeric pair of cytotoxic phenylspirodrimane dimers from Stachybotrys chartarum

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Chinese Chemical Letters 2019年第2期30卷 435-438页

作者： Min Zhang jiamin feng Xiaona Jia Jinlian Zhao Jimei Liu Ridao Chen Kebo Xie Dawei Chen Yan Li Dan Zhang Jungui Dai State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia Medica Chinese Academy of Medical Sciences and Peking Union Medical College Key Laboratory of Biosynthesis of Natural Products of National Health and Family Planning Commission Institute of Materia Medica Chinese Academy of Medical Sciences and Peking Union Medical College

Bistachybotrysins D and E (1 and 2), one stereoisomeric pair of phenylspirodrimane dimers, were isolated from Stachybotrys chartarum CGMCC 3.5365. They represent novel phenylspirodrimane dimers with a central [6,5,6]-tricyclic carbon scaffold containing a cyclopentanone core. The structures of 1 and 2 were elucidated through extensive spectroscopic data analysis, and their absolute configurations were characterized by calculated electronic circular dichroism (ECD). Compounds 1 and 2 displayed potent cytotoxic activity against the four human tumor cell lines HCT116, BGC823, Daoy and HepG2 with IC_ (50)values ranging from 6.7 μmol/L to 11.6 μmol/L. Furthermore, a plausible biogenetic pathway for 1 and 2 is proposed.

关键词： Bistachybotrysin Stereoisomeric pair Phenylspirodrimane dimer Cytotoxic activity Stachybotrys chartarum

面向“进出平衡”的耕地补充潜力识别--以莱西市为例

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城市勘测 2025年第1期 164-169页

作者：滕永佳李祥王福丽冯佳敏沙海龙隋云峰孙晓明青岛市勘察测绘研究院山东青岛266000 青岛市海陆地理信息集成与应用重点实验室山东青岛266000 青岛城市学院山东青岛266106 北京语言大学国际学生教育政策与评价研究院北京100083

耕地“进出平衡”是管控耕地“非粮化”的有效手段。针对传统方法容易造成耕地布局劣化的问题,以莱西市为例,构建了融合自然适宜性、区位适配性、复耕经济性、规划协调性四个维度的耕地补充潜力识别模型。研究发现,莱西市耕地补充综合... 详细信息

耕地“进出平衡”是管控耕地“非粮化”的有效手段。针对传统方法容易造成耕地布局劣化的问题,以莱西市为例,构建了融合自然适宜性、区位适配性、复耕经济性、规划协调性四个维度的耕地补充潜力识别模型。研究发现,莱西市耕地补充综合评价平均分值为80.93,表明该地区耕地整治条件良好,但也存在明显的区域差异性。同时,识别出27个耕地补充的重点区域,并发现不同镇街的耕地补充潜力差异显著。研究结果可以为耕地补充项目的选址和规划提供科学参考。

关键词：进出平衡耕地整治耕地用途管控空间分析粮食安全

Assessment on Thermal Storage Performance of Capsule-Type Composite Phase-Change Materials

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Journal of Thermal Science 2025年第02期 448-464页

作者： MA Rui GUO jiamin WANG Zilong WANG feng College of Energy and Power Engineering Inner Mongolia University of Technology Key Laboratory of Wind and Solar Energy Utilization Mechanism and Optimization in Inner Mongolia Inner Mongolia University of Technology

To address the intermittent challenges of new energy and waste heat recovery as well as counteract the issues of corrosion and overcooling in phase-change materials,this study develops and investigates a medium-temperature phase-change capsule(PCC) through experiments and numerical *** thermal cycle stability testing of the developed PCC,subjected to 150 cycles to evaluate its performance,demonstrated that the capsule's surface remained intact with no signs of *** enthalpy-porosity method combined with the volume-of-fluid method was used to establish a numerical model to simulate the phase-change process in capsules with two structures:one with a central cavity and the other with a top *** indicated that when using 304 stainless steel as the wall material for both structures,the PCC with the centrally located cavity melted28.3% faster than that with the cavity at the *** using different materials as wall coverings,the melting rate of the PCC made of polytetrafluoroethylene(PTFE) was 22.1% slower than that of the capsule made of 304stainless ***,the modified PTFE PCC melted 15.2% faster than the stainless steel-based ***,when using PCCs having different diameters,the time differences for complete melting between the PTFE and stainless steel-based PCCs were 118 s and 66 s for the capsules having diameters of 24 mm and 16 mm,respectively,indicating that the time difference decreased with decreasing capsule diameter.

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医疗机构行使紧急救治权的法律风险分析及对策——以《中华人民共和国民法典》第1220条为例

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中国医院管理 2024年第6期44卷 83-86页

作者：冯嘉旻龚波广州医科大学卫生法治与政策研究中心广东广州511436

《中华人民共和国民法典》第1220条是专门为医疗机构与医务人员抢救生命垂危的患者而制定的,旨在化解医疗机构的应急抢救权利与病患的知情同意权利之间的矛盾。鉴于相应法律法规的欠缺、组织结构的欠佳和体系的漏洞等问题,医疗机构在实... 详细信息

《中华人民共和国民法典》第1220条是专门为医疗机构与医务人员抢救生命垂危的患者而制定的,旨在化解医疗机构的应急抢救权利与病患的知情同意权利之间的矛盾。鉴于相应法律法规的欠缺、组织结构的欠佳和体系的漏洞等问题,医疗机构在实施紧急救治的时候有可能存在一定的风险。梳理和考察现行法中关于医疗机构紧急救治的相关规定,发现有必要优化相关法律条款及司法解释,建立健全以伦理委员会为核心的病例评价体系,完善医疗救助基金与保险制度,避免医务人员陷于“情与理”的困境。

关键词：医疗机构紧急救治权医务人员知情同意权

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ZKB型直线振动筛的应用及优化研究

当代化工研究 2020年第2期 77-78页

作者：冯嘉敏同煤集团挖金湾煤业公司调度室

为了解决高应力引起的共振问题,ZKB型直线振动筛已成为煤矿生产中重要组成部分。本文以ZKB直线振动筛为研究对象,对其固有频率和工作受力情况进行了分析。

关键词： ZKB型直线振动筛问题应用优化