检索结果-南通市图书馆

Determination of Reactive Intermediates During Anodic Oxygen-transfer Reactions at Lead Dioxide

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2004年第3期20卷 289-293页

作者： AIShi-yun ZHANGWen GAOMeng-nan GUFen-lin WANGQing-jiang JINLi-tong DepartmentofChemistry EastChinaNormalUniversityShanghai200062P.R.China

The anodic discharge of water to produce adsorbed hydroxyl free radicals(·OH) is considered to be a prerequisite to anodic O-transfer reactions at a PbO_2 electrode. In this work,a method was studied by means of high-performance liquid chromatography(HPLC) combined with electrochemical detection(ED) so as to investigate the production of hydroxyl free radicals(·OH) in the process of the anodic discharge of H_2O at a PbO_2 electrode. The voltammetric data obtained at the PbO_2 electrode for the oxidation of salicylic acid to salicylate hydroxylation products(DHBAs) and the detection of DHBAs by means of HPLC-ED confirm the proposed mechanism.

关键词： PbO_2 electrode Electrocatalysis Hydroxyl free radical Salicylic acid HPLC

Reliability Evaluation of Machine Center Components Based on Cascading Failure Analysis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第4期30卷 933-942页

作者： Ying-Zhi Zhang Jin-tong Liu Gui-Xiang Shen Zhe Long Shu-guang Sun College of Mechanical Science and Engineering Jilin University College of Management Science and Engineering Shandong Normal University

In order to rectify the problems that the com- ponent reliability model exhibits deviation, and the evalu- ation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influ- enced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm. Based on the comprehensive failure probability function and total probability formula, the inherent failure proba- bility function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following： 1） The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2） The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree ofthe system component, which provides a theoretical basis for reliability allocation of machine center system.

关键词： s Cascading failure Machine centercomponents Reliability evaluation Pagerank algorithmInfluenced degree

Experiment and Simulation for Rolling of Diamond–Cu Composites

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2017年第8期30卷 791-800页

作者： yun-Long Wang Kai-Kun Wang Yu-Wei Wang guang-Chen Li School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Department of Engineering University of LeicesterUniversity Road Leicester LE1 7RH UK Tianjin Xiangtong Electronic Company LTD Tianjin 301800 China

We demonstrate an innovative preparation approach of diamond/Cu composites by powder-in-tube technique and rolling. A small copper tube was loaded with Ti- and Cu-coated diamond particles, mad then the diamond particles were combined with Cu matrix by composite rolling. The morphology and element distribution of the interface between diamond and Cu were determined by scanning electron microscopy and energy-dispersive spectrometer. Finite element method （FEM） simulation was used to analyze the rolling process associated with experiment by DEFORM-3D. The final experimental results showed that homogeneous distribution of diamond particles could be observed in the center layer of the composites. According to the contrast experiments, the sample, whose diamond particle size is 0.12-0.15 mm and thickness of pre-rolling is 1.2 mm, showed relatively complete morphologies and homogeneous distribution. Experimental results indicated a poor efficacy of excessive rolling reduction. The thermal conductivity of the composites is about 453 W （m K）-1 by theoretical calculation. For FEM simulation, roiling strain and temperature field of the composites were simulated by DEFORM-3D. Simulation results were interpreted, and numerical results verified the reliability of the model. The simulation predicted that the local area of large strain, indicative of the strain along the thickness direction, could be intensified by adding diamond particles.

关键词： Diamond/Cu composites Powder-in-tube technique (PIT) Rolling Finite element method(FEM) simulation

The corrosion of AA2037 aluminum alloy in alkaline aqueous solution studied using slow positron beam spectroscopy

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2016年第2期27卷 6-13页

作者： Jiao-Jiao Wang Zhe-Jie Zhu Wei Yang Yi-Chu Wu tong-guang Zhai Hubei Key Laboratory of Nuclear Solid Physics School of Physics and Technology Wuhan University Chemical and Materials Engineering Department University of Kentucky

Corrosion behavior of AA2037 T8 Al alloy in a1 M Na OH aqueous solution was investigated using slow positron beam, together with microscopy techniques and electrochemical tests. The alloy was homogenized at 510℃ for 2 h and 30 s, respectively, before final peak aging, so that one Sample A had more dispersoids than Sample B after homogenization. It was found that S parameter of the Doppler-broadened annihilation was significantly decreased near the surface in both samples in the alkaline solution. With increasing the dissolution time,Sample A showed a slower decrease rate than Sample B,which might imply that the preexistence of more dispersoids might hinder the corrosion process in Sample *** electron microscopy and atomic force microscopy observations found that the surfaces of both samples were uniformly thinned due to intense chemical dissolution by the attack of OH-. With increasing the dissolution time,Sample B was corroded more substantially and produced more and larger pits in a short dissolution time than Sample A. Furthermore, polarization curves showed that Sample A had a lower corrosion current and corrosion rate than Sample B, which revealed that the presence of the dispersoids was responsible for the better corrosion resistance in the alloy.

关键词：慢正电子束碱性水溶液腐蚀行为铝合金扫描电子显微镜光谱溶解时间电化学测试

Determination of Trace Thiocyanate by a Chitosan-Modified Glassy Carbon Electrode

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2002年第3期18卷 316-320页

作者： LU guang han YAO Xin ZHOU Xiang chun ZHAN tong LONG De wu Department of Chemistry Central China Normal UniversityWuhan 430079P.R.China Department of Chemistry Hubei Jingzhou Teacher CollegeJinzhou 434100P.R.China

A chitosan modified glassy carbon electrode(CMGCE) was employed for the determination of thiocyanate. The measurement was carried out by means of anodic stripping voltammetry. The effects of several experimental parameters, such as pH, the amount of modifier, deposition potential and deposition time were studied for analytical application, respectively. A liner response was obtained in the concentration range of 3 5×10 -8 - 9.3×10 -7 g/mL of SCN -. The detection limit was found to be 1.9×10 -8 g/mL. The method was satisfactorily used to detect SCN - in saliva.

关键词： Anodic stripping voltammetry Thiocyanate CMGCE Saliva

Coupling Dynamic Model of Chatter for Cold Rolling

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2010年第12期17卷 30-34页

作者： YANG Xu tong Chao-nan YUE guang-feng MENG Jian-ji School of Information Engineering University of Science and Technology Beijing Beijing 100083 China Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology- Beijing Beijing 100083 China Central Research Institute of Building and Construction Co Ltd MCC Group Beijing 100088 China

In order to build high accuracy integral dynamic models of cold rolling mill system, by analyzing the vibration process of cold rolling, the dynamic model of 4-h mill, including the rolling process model, the mill roll stand structure model and the hydraulic servo system model is built. These three models are coupled and linearized, then the multiple input and multiple output （MIMO） linear transfer function model of single stand 4-h cold mill system is obtained. The model with the proposed data proves its validity, meanwhile the effects of different working conditions on the stability of cold rolling mill system have been discussed. Simulation resulsts show that the model accords with former models and has its own advancement. It contributes to the further study and supression of coupling vibraiton.

关键词： cold rolling chatter dynamic modeling coupling simulation

A novel differential multiuser detection algorithm for multiuser MIMO-OFDM systems

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第10期11卷 798-807页

作者： Zheng-min KONG guang-xi ZHU Qiao-ling tong Yan-chun LI Department of Electronics and Information Engineering Huazhong University of Science and Technology Wuhan 430074 China Wuhan National Lab for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

We propose an efficient low bit error rate(BER) and low complexity multiple-input multiple-output(MIMO) multiuser detection(MUD) method for use with multiuser MIMO orthogonal frequency division multiplexing(OFDM) *** is a hybrid method combining a multiuser-interference-cancellation-based decision feedback equalizer using error feedback filter(MIMO MIC DFE-EFF) and a differential *** proposed method,termed 'MIMO MIC DFE-EFF with a differential algorithm' for short,has a multiuser feedback *** describe the schemes of MIMO MIC DFE-EFF and MIMO MIC DFE-EFF with a differential algorithm,and compare their minimum mean square error(MMSE) performance and computational *** results show that a significant performance gain can be achieved by employing the MIMO MIC DFE-EFF detection algorithm in the context of a multiuser MIMO-OFDM system over frequency selective Rayleigh *** MIC DFE-EFF with the differential algorithm improves both computational efficiency and BER performance in a multistage structure relative to conventional DFE-EFF,though there is a small reduction in system performance compared with MIMO MIC DFE-EFF without the differential algorithm.

关键词： Multiuser detection(MUD) Orthogonal frequency division multiplexing(OFDM) Multiple-input multiple-output (MIMO) Decision feedback equalizer(DFE) Error feedback filter(EFF) Differential algorithm

Combined thoracic paravertebral block and interscalene brachial plexus block for modified radical mastectomy:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第17期10卷 5741-5747页

作者： Zhou-Ting Hu guang Sun Shen-tong Wang Kai Li Department of Anesthesia China-Japan Union Hospital of Jilin UniversityChangchun 130033Jilin ProvinceChina Department of Breast Surgery China-Japan Union Hospital of Jilin UniversityChangchun 130033Jilin ProvinceChina

BACKGROUND Modified radical mastectomy(MRM)is the most common surgical treatment for breast *** anesthesia poses a challenge in fragile MRM patients,including cardiovascular instability,insufficient postoperative pain control,nausea and *** paravertebral block(TPVB)is adequate for simple mastectomy,but its combination with interscalene brachial plexus block(IBPB)has not yet been proved to be an effective anesthesia method for *** SUMMARY We describe our experience of anesthesia and pain management in 10 patients with multiple *** ultrasound-guided TPVB was placed at T2-T3 and T5-T6,and combined with IBPB,with administration of 10,15 and 5 mL of 0.5%ropivacaine,respectively.A satisfactory anesthetic effect was proved by the absence of ipsilateral tactile sensation within 30 *** 3 mg/kg/h and oxygen supplementation via a nasal cannula were administered during *** of the patients required additional narcotics,vasopressors,or conversion to general *** maximum pain score was 2 on an 11-point numerical rating *** patients required one dose of celecoxib 8 h postoperatively and none reported nausea or *** This case series demonstrated that combined two-site TPVB and small-volume IBPB with sedation can be used as an alternative anesthetic modality for MRM,providing good postoperative analgesia.

关键词： Modified radical mastectomy Paravertebral block Brachial plexus block Sedation Case report

Accelerating inverse crystal structure prediction by machine learning:A case study of carbon allotropes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2020年第6期15卷 97-103页

作者： Wen tong Qun Wei Hai-Yan Yan Mei-guang Zhang Xuan-Min Zhu School of Physics and Optoelectronic Engineering Xidian UniversityXi'an 710071China College of Chemistry and Chemical Engineering Baoji University of Arts and SciencesBaoji 721013China College of Physics and Optoelectronic Technology Baoji University of Arts and SciencesBaoji 721016China School of Information Guizhou University of Finance and EconomicsGuiyang 550025China

Based on structure prediction method,the machine learning method is used instead of the density functional theory(DFT)method to predict the material properties,thereby accelerating the material search *** this paper,we established a data set of carbon materials by high-throughput calculation with available carbon structures obtained from the Samara Carbon Allotrope *** then trained a machine learning(ML)model that specifically predicts the elastic modulus(bulk modulus,shear modulus,and the Young's modulus)and confirmed that the accuracy is better than that of AFLOW-ML in predicting the elastic modulus of a carbon *** further combined our ML model with the CALYPSO code to search for new carbon structures with a high Young's modulus.A new carbon allotrope not included in the Samara Carbon Allotrope Database,named Cmcm-C24,which exhibits a hardness greater than 80 GPa,was firstly *** Cmcm-C24 phase was identified as a semiconductor with a direct *** structural stability,elastic modulus,and electronic properties of the new carbon allotrope were systematically studied,and the obtained results demonstrate the feasibility of ML methods accelerating the material search process.

关键词： machine learning crystal structure prediction carbon