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NUMERICAL RESEARCH ON WATER GUIDE BEARING OF HYDRO-GENERATOR UNIT USING FINITE VOLUME METHOD

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Journal of Hydrodynamics 2007年第5期19卷 635-642页

作者： peng Yu-cheng CHEN xi-yang ZHANG Ke-wei HOU Guo-xiang School of Energy and Power. Engineering Huazhong University of Science and Technology Wuhan 430074 China School of Traffic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

With the consideration of the geometry of tilting pad journal bearing, a new form of the Reynolds equation was derived in this article. The film thickness, the squeeze motion of the journal and the rotation motion of the pad were explicitly contained in the equation. Based on this equation, together with the equilibrium equation of pad pivot, the water guide bearing used in the Gezhouba 10 F hydro-generator unit was numerically researched. The new Reynolds equation for the lubricating film was solved using Finite Volume （FV） discretization, Successive Over-Relaxation （SOR） iteration method and C＋＋ code are included. According to the numerical solution, and the stability of the film and the influences of the film thickness, the journal squeeze effect and the pad rotation effect on film force were discussed. The results indicate that the squeeze effect can not be neglected, although the rotation effect is negligible for both low-speed and high-speed bearings, so the computing time could be greatly reduced.

关键词： hydro-generator unit Reynolds equation,tilting pad journal bearing Finite Volume (FV) method

NUMERICAL STUDY OF CAVITATION ON THE SURFACE OF THE GUIDE VANE IN THREE GORGES HYDROPOWER UNIT

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Journal of Hydrodynamics 2010年第5期22卷 703-708页

作者： peng Yu-cheng CHEN xi-yang CAO Yan HOU Guo-xiang School of energy and Power Engineering Huazhong University of Science and Technology Wuhan 430074 China College of Electronic Information Engineering Wuhan Polytechnic Wuhan 430074 China School of Traffic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

Large-area erosions such as rust and obvious cavitation were found on the surface of the guide vane in Three Gorges hydropower units. A numerical explanation of the cavitation is given in this article. At first, based on the characteristic performance curves of the prototype hydro-turbine supplied by ALSTOM together with the actual operating conditions, an operating point is chosen for numerical analysis using the Reynolds-Averaged Navier-Stokes （RANS） equations. The flow passages from the inlet of the spiral case to the outlet of the draft tube are included in the computational domain. The results show that the static pressure on the guide vane surface is much higher than the critical pressure of cavitation. Secondly, a tiny protrusion on the guide vane surface is considered and the problem is simplified to a 2-D problem to study the local detailed flow near the guide vane surface. The protrusion is 0.5 mm in height and is 5.0 mm in width. On the basis of the results of RANS simulations, the 2-D problem is studied using the Large Eddy Simulation （LES）. It is shown that there exists a region in which the static pressure reaches a level below the vapor pressure of the water. Thirdly, a cavitation model is included for the 0.5 mm protrusion case and another tiny pit case, with a tiny pit 0.3 mm in depth and 1.0 mm in width. The results show that vapor bubble exists at the protrusion entrance and the pit exit as the low pressure regions.

关键词： cavitation guide vane numerical analysis

Working condition recognition of sucker rod pumping system based on 4-segment time-frequency signature matrix and deep learning

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Petroleum Science 2024年第1期21卷 641-653页

作者： Yun-peng He Hai-Bo cheng peng Zeng Chuan-Zhi Zang Qing-Wei Dong Guang-xi Wan xiao-Ting Dong State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016LiaoningChina Key Laboratory of Networked Control Systems Chinese Academy of SciencesShenyang 110016LiaoningChina Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169LiaoningChina University of Chinese Academy of Sciences Beijing100049China School of Artifcial Intelligence Shenyang University of TechnologyShenyang 110870LiaoningChina

High-precision and real-time diagnosis of sucker rod pumping system(SRPS)is important for quickly mastering oil well *** learning-based method for classifying the dynamometer card(DC)of oil wells is an efficient diagnosis ***,the input of the DC as a two-dimensional image into the deep learning framework suffers from low feature utilization and high computational ***,different SRPSs in an oil field have various system parameters,and the same SRPS generates different DCs at different ***,there is heterogeneity in field data,which can dramatically impair the diagnostic *** solve the above problems,a working condition recognition method based on 4-segment time-frequency signature matrix(4S-TFSM)and deep learning is presented in this ***,the 4-segment time-frequency signature(4S-TFS)method that can reduce the computing power requirements is proposed for feature extraction of DC ***,the 4S-TFSM is constructed by relative normalization and matrix calculation to synthesize the features of multiple data and solve the problem of data ***,a convolutional neural network(CNN),one of the deep learning frameworks,is used to determine the functioning conditions based on the *** on field data verify that the proposed diagnostic method based on 4S-TFSM and CNN(4S-TFSM-CNN)can significantly improve the accuracy of working condition recognition with lower computational *** the best of our knowledge,this is the first work to discuss the effect of data heterogeneity on the working condition recognition performance of SRPS.

关键词： Sucker-rod pumping system Dynamometer card Working condition recognition Deep learning Time-frequency signature Time-frequency signature matrix

Effect of cytochrome P4502C19(CYP2C19)gene polymorphism and clopidogrel reactivity on long term prognosis of patients with coronary heart disease after PCI

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Journal of Geriatric Cardiology 2024年第1期21卷 90-103页

作者： cheng-Yan HU Yan-Ling WANG Zhen-xing FAN xi-peng SUN Shuai WANG Zhi LIU Department of Geriatrics Fu Xing HospitalCapital Medical UniversityBeijingChina Department of Cardiology Xuanwu Hospital Capital Medical UniversityBeijingChina Emergency Department of Xuanwu Hospital Capital Medical UniversityBeijingChina

Objective To investigate the impact of CYP2C19 gene polymorphism on clopidogrel reactivity and its association with longterm clinical outcome in patients with coronary heart disease(CHD)undergoing percutaneous coronary intervention(PCI).Methods In total,675 patients were *** on the platelet inhibition rate,patients were categorized into two groups:clopidogrel low responsiveness(CLR)and normal clopidogrel responsiveness(NCR).The CLR group was divided into ticagrelor and clopidogrel group based on the antiplatelet drugs used in the follow-up *** were classified into three groups(normal metabolizer,intermediate metabolizer,and poor metabolizer)based on the CYP2C19 *** aimed to evaluate the impact of CYP2C19 gene polymorphism on clopidogrel *** cumulative rates of 12-month all-cause deaths,major adverse cardiovascular events(MACCEs),and bleeding events were *** CLR was observed in 44.4%of the overall *** differences were observed in the platelet inhibition rate of clopidogrel among the three metabolic genotypes(P0.05).Conclusions Low response to clopidogrel in CHD patients is correlated with CYP2C19 gene ***2C19 genotyping combined with platelet reactivity is an independent predictor of 12-months MACCEs in patients with clopidogrel treatment after PCI,which is better than either test alone.

关键词： CYP2C19 drugs PCI

“Blocking and rebalance” mechanism-guided design strategies of bimetallic doped 2D a-phosphorus carbide as efficient catalysts for N2 electroreduction

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Journal of Energy Chemistry 2024年第10期97卷 68-78页

作者： cheng He Jianglong Ma Shen xi Wenxue Zhang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University School of Materials Science and Engineering Chang'an University

Compared to single atom catalysts（SACs）,the introduction of dual atom catalysts（DACs） has a significantly positive effect on improving the efficiency in the electrocatalytic nitrogen reduction reaction（NRR） which provides an environmental alternative to the Haber-Bosch ***,the research on the mechanism and strategy of designing bimetallic combinations for better performance is still in its early ***,based on "blocking and rebalance" mechanism,45 combinations of bimetallic pair doped α-phosphorus carbide（TMATMB@PC） are investigated as efficient NRR catalysts through density functional theory and machine learning *** a multi-step screening,the combinations of TiV,TiFe,MnMo,and FeW exhibit highly efficient catalytic performance with significantly lower limiting potentials（-0.17,-0.18,-0.14,and-0.30 V,respectively）.Excitingly,the limiting potential for CrMo and CrW combinations is 0 V,which are considered to be extremely suitable for the NRR *** mechanism of "blocking and rebalance" is revealed by the exploration of charge transfer for phosphorus atoms in electron blocking ***,the descriptor φ is proposed with machine learning,which provides design strategies and accurate prediction for finding efficient *** work not only offers promising catalysts TMATMB@PC for NRR process but also provides design strategies by presenting the descriptor φ.

关键词： 2D α-phosphorus carbide DACs Inherent attributes Machine learning Nitrogen reduction reaction

Simulation of Fracture Process of Lightweight Aggregate Concrete Based on Digital Image Processing Technology

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Computers, Materials & Continua 2024年第6期79卷 4169-4195页

作者： Safwan Al-sayed xi Wang Yijiang peng Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing100124China

The mechanical properties and failure mechanism of lightweight aggregate concrete(LWAC)is a hot topic in the engineering field,and the relationship between its microstructure and macroscopic mechanical properties is also a frontier research topic in the academic *** this study,the image processing technology is used to establish a micro-structure model of lightweight aggregate *** the information extraction and processing of the section image of actual light aggregate concrete specimens,the mesostructural model of light aggregate concrete with real aggregate characteristics is *** numerical simulation of uniaxial tensile test,uniaxial compression test and three-point bending test of lightweight aggregate concrete are carried out using a new finite element method-the base force element method ***,the image processing technology is used to produce beam specimens,uniaxial compression specimens and uniaxial tensile specimens of light aggregate concrete,which can better simulate the aggregate shape and random distribution of real light aggregate ***,the three-point bending test is numerically ***,the uniaxial compression specimen generated by image processing technology is numerically ***,the uniaxial tensile specimen generated by image processing technology is numerically *** mechanical behavior and damage mode of the specimen during loading were *** results of numerical simulation are compared and analyzed with those of relevant *** feasibility and correctness of the micromodel established in this study for analyzing the micromechanics of lightweight aggregate concrete materials are *** processing technology has a broad application prospect in the field of concrete mesoscopic damage analysis.

关键词： Digital image processing lightweight aggregate concrete mesoscopic model numerical simulation fracture analysis bending beams

Clinical analysis of uncinate process carcinoma of the pancreas

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Hepatobiliary & Pancreatic Diseases International 2003年第4期2卷 605-608页

作者： Chun Ye peng-cheng xi xian-Gui Hu the Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China Department of General Surgery Changhai Hospital Second Military Medical University Shanghai 200433 China. thomas2000@***

OBJECTIVE: To analyse the clinical features of uncinate process carcinoma of the pancreas and the diagnosis and treatment of this malignancy. METHOD: Fifty-nine patients with pancreas uncinate process carcinoma treated from January 1998 to September 2002 at our hospital were analysed retrospectively. RESULTS: Major symptoms of these patients were upper abdominal pain accompanied with lumbar pain, body weight loss and jaundice. Thirty-seven patients received regional pancreaticoduodenectomy (RP), 16 partial resection of the superior mesenteric vein-portal vein (SMV-PV) or superior mesenteric artery (SMA) and reconstruction, 1 anhydrous alcohol injection in the celiac nerve plexus, regional chemotherapy via a chemotherapy pump, and liver biopsy, and 5 no operation. The survival of the patients after operation was 2-46 months (median 12.1 months). Eleven patients are still alive with a longest survival of 46 months. The 1- and 3-year survival rates were 37.7% and 5.6%. CONCLUSIONS: Pancreas uncinate process carcinoma invading the adjacent SMV/SMA-PV causes difficulty in early diagnosis and poor prognosis, which are related to its location, not tumor's aggressive nature. This carcinoma has a high resection rate of 89.8%.

关键词： uncinate process carcinoma pancreas pancreaticoduodenectomy regional

Fault Identification for Shear-Type Structures Using Low-Frequency Vibration Modes

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2769-2791页

作者： Cuihong Li Qiuwei Yang xi peng School of Civil Engineering Shaoxing UniversityShaoxing312000China School of Civil and Transportation Engineering Ningbo University of TechnologyNingbo315211China Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang Ningbo University of TechnologyNingbo315211China

Shear-type structures are common structural forms in industrial and civil buildings,such as concrete and steel frame *** diagnosis of shear-type structures is an important topic to ensure the normal use of *** main drawback of existing damage assessment methods is that they require accurate structural finite element models for damage ***,for many shear-type structures,it is difficult to obtain accurate *** order to avoid finite elementmodeling,amodel-freemethod for diagnosing shear structure defects is developed in this *** method only needs to measure a few low-order vibration modes of the *** proposed defect diagnosis method is divided into two *** the first stage,the location of defects in the structure is determined based on the difference between the virtual displacements derived from the dynamic flexibility matrices before and after *** the second stage,damage severity is evaluated based on an improved frequency sensitivity *** innovations of this method lie in two *** first innovation is the development of a virtual displacement difference method for determining the location of damage in the shear *** second is to improve the existing frequency sensitivity equation to calculate the damage degree without constructing the finite *** has been verified on a numerical example of a 22-story shear frame structure and an experimental example of a three-story steel shear *** on numerical analysis and experimental data validation,it is shown that this method only needs to use the low-order modes of structural vibration to diagnose the defect location and damage degree,and does not require finite element *** proposed method should be a very simple and practical defect diagnosis technique in engineering practice.

关键词： Fault diagnosis shear steel structure vibration mode dynamic flexibility frequency sensitivity

Metal±organic cage as fluorescent probe for LiPF6 in lithium batteries

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Green Energy & Environment 2024年第10期9卷 1592-1600页

作者： xi Li Dehua Xu Aoxuan Wang chengxin peng xingjiang Liu Jiayan Luo Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin University School of Materials Science and Engineering University of Shanghai Science and Technology State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong University

Lithium hexafluorophosphate （LiPF6）,the most commonly used lithium battery electrolyte salt,is vulnerable to heat and *** and qualitative determination the variation of Li PF6have always relied on advanced ***,we develop a fast,convenient,high-selective fluorescence detection method based on metal±organic cages （MOC）,whose emission is enhanced by nearly 20 times in the presence of Li PF6with good stability and photobleaching *** fluorescent probe can also detect moisture in battery *** propose and verify that the luminescence enhancement is due to the presence of hydrogen bond-induced enhanced emission effect in *** excitation-emission matrix spectra and variable-temperature nuclear magnetic resonance spectroscopy are employed to clarify the role of hydrogen bonds in guest-loaded *** functional theory （DFT） calculation is applied to simulate the structure of host-guest complexes and estimate the adsorption energy involved in the *** precisely matched lock-and-key model paves a new way for designing and fabricating novel host structures,enabling specific recognition of other target compounds.

关键词： Metal-organic cage Selective fluorescence probe Moisture detection Hydrogen bond Host-guest complex