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High-frequency and low-amplitude relative sea-level changes in the Turonian Ferron Notom Delta, Henry Mountains region Utah, USA: implications for sequence stratigraphy and hydrocarbon exploration

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Petroleum Science 2014年第1期11卷 14-27页

作者： li weiguo Zhu Yijie BP America Inc. 501 Westlake Park Chevron Energy Technology Company

The Turonian Notom Delta is one of the Ferron fluvial-deltaic wedges deposited in the foreland basins of the Cretaceous Seaway of North *** wedge is exposed three dimensionally in the Henry Mountains region Utah,***-resolution sequence stratigraphic analysis along a 35 km dip-oriented outcrop belt shows that the wedge consists of six depositional *** and Inoceramid biostratigraphy and 40Ar/39Ar age dating of various bentonites show that the wedge was deposited from 91.25 Ma to 90.63 Ma,an interval of merely 0.62 *** each sequence is formed over a similar time span,each sequence,thus,represents about 105 yr,suggesting high-frequency depositional *** of relative sea-level changes,built on shoreline trajectory,is 2-61 m,with an average of only 20 *** incision during high-frequency and low-amplitude relative sealevel fall is mainly around the highstand *** diminishes rapidly up dip and down dip,and the resultant incised valleys are narrow and *** sea-level fluctuations also result in small,stratigraphically complex shoreline sandstones that need special attention during hydrocarbon exploration.

关键词： Ferron Notom Delta time stratigraphy shoreline trajectory age dating Cretaceous Seaway of North America

The temperature-dependent fracture strength model for ultra-high temperature ceramics

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Acta Mechanica Sinica 2010年第2期26卷 235-239页

作者： weiguo li Fan Yang Daining Fang College of Resource and Environment Science Chongqing University 400030 Chongqing China AML Department of Engineering Mechanics Tsinghua University 100084 Beijing China College of Engineering Peking University 100871 Beijing China

Breaking down the entire structure of a material implies severing all the bonds between its atoms either by applying work or by heat transfer. Because bond-breaking is indifferent to either means, there is a kind of equivalence between heat energy and strain energy. Based on this equivalence, we assume the existence of a constant maximum storage of energy that includes both the strain energy and the corresponding equivalent heat energy. A temperaturedependent fracture strength model is then developed for ultrahigh temperature ceramics （UHTCs）. Model predictions for UHTCs, HfB2, TiC and ZrB2, are presented and compared with the experimental results. These predictions are found to be largely consistent with experimental results.

关键词： Ultra-high temperature ceramics · Equivalent energy · Critical failure energy · Strength model

Self-organized pattern on the surface of a metal anode in low-pressure DC discharge

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Plasma Science and Technology 2018年第3期20卷 63-71页

作者： Yaqi YANG weiguo li College of Electrical Engineering North China Electric Power University Beijing 102206. People＇s Republic of China

Self-organization phenomena on the surface of a metal electrode in low-pressure DC discharge is studied. In this paper, we carry out laboratory investigations of self-organization in a lowpressure test platform for 100–200 mm rod-plane gaps with a needle tip, conical tip and hemispherical tip within 1–10 k Pa. The factors influencing the pattern profile are the pressure value, gap length and shape of the electrode, and a variety of pattern structures are observed by changing these factors. With increasing pressure, first the pattern diameter increases and then decreases. With the needle tip, layer structure, single-ring structure and double-ring structure are displayed successively with increasing pressure. With the conical tip, the ring-like structure gradually forms separate spots with increasing pressure. With the hemispherical tip, there are anode spots inside the ring structure. With the increase of gap length, the diameter of the selforganized pattern increases and the profile of the pattern changes. The development process of the pattern contains three key stages： pattern enlargement, pattern stabilization and pattern shrink.

关键词： self-organized pattern low pressure DC voltage metal anode pattern profile

A Three-phase Integrated Power Electronic Transformer with the Capability of DC Fault Clearance

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CSEE Journal of Power and Energy Systems 2021年第4期7卷 785-796页

作者： Yunfei Xu Guangfu Tang weiguo li Guoliang Zhao Zhanfeng Deng State Key Laboratory of Advanced Transmission Technology(Global Electricity Interconnection Research Institute Co.Ltd.) Changping DistrictBeijing 102211China

This paper presents a three-phase integrated power electronic transformer(PET)topology with the capability of DC fault clearance based on the investigation of PET *** proposed PET has three ports of high-voltage AC,high-voltage DC and low-voltage DC,which can achieve the flexible access of distributed energy resources・The power unit of the PET adopts a three-phase integrated topology,and the single-phase fluctuating power in the DC-link capacitor is reduced by a 4-port DC/DC converter,thereby reducing the capacitance of the DC-link capacitor;Meanwhile,the power unit uses the clamp double sub-module(CDSM)to allow for self-clearing of the short-circuit fault on the high-voltage DC ***,this paper verifies the proposed PET through an EMT simulation and experimental prototype.

关键词： DC fault clearing experimental verification power electronic transformer three phase integration

Effects of mechanical boundary conditions on thermal shock resistance of ultra-high temperature ceramics

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Applied Mathematics and Mechanics(English Edition) 2015年第2期36卷 201-210页

作者： Tianbao CHENG weiguo li Yushan SHI Wei LU Daining FANG Chongqing Key Laboratory of Heterogeneous Material Mechanics College of Aerospace Engineering Chongqing University State Key Laboratory of Coal Mine Disaster Dynamics and Control College of Resources and Environmental Science Chongqing University State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University

The effects of mechanical boundary conditions, often encountered in thermalstructural engineering, on the thermal shock resistance（TSR） of ultra-high temperature ceramics（UHTCs） are studied by investigating the TSR of a UHTC plate with various types of constraints under the first, second, and third type of thermal boundary conditions. The TSR of UHTCs is strongly dependent on the heat transfer modes and severity of the thermal environments. Constraining the displacement of the lower surface in the thickness direction can significantly decrease the TSR of the UHTC plate, which is subject to the thermal shock at the upper surface. In contrast, the TSR of the UHTC plate with simply supported edges or clamped edges around the lower surface is much better.

关键词： thermal shock resistance(TSR) ultra-high temperature ceramic(UHTC) mechanical boundary condition temperature-dependent material property thermal environment

Effects of Nitrogen Sources and Concentrations on the Growth of Different Phytoplankton Taxa

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Journal of Ocean University of China 2021年第3期20卷 721-728页

作者： liU Lei WANG Zhaohui WANG Chaofan li weiguo NIE Xiangping Department of Ecology College of Life Science and TechnologyJinan UniversityGuangzhou 510632China Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering Ministry of EducationGuangzhou 510632China

Effects of different nitrogen(N)compounds and concentrations on the growth of the three different phytoplankton taxa,Skeletonema costatum(Bacillariophyceae),Prorocentrum micans(Dinophyceae),and Chattonella marina(Raphidophyceae),were *** Monod equation was applied to examine effects of N concentrations on the growth of algal *** showed that nitrate(NO_(3)-N)and urea served as good N sources for the three phytoplankton *** grew well on all of the seven N *** can effectively use the two amino acids,glycine(Gly)and serine(Ser),however cannot utilize alanine(Ala),threonine(Thr),and asparaginic acid(Asp).*** cannot grow in five amino acid *** of the three phytoplankton taxa grew well under different proportions of urea-N,and *** grew significantly better in medium with both NO_(3)-and *** values of maximum growth rate(μmax)and half-saturation nutrient concentration(KS)for NO_(3)-N were 0.71 divisions d−1 and 53.55μmolL^(−1) for ***,0.67 divisions d−1 and 23.31μmolL^(−1) for ***,and 0.23 divisionsd−1 and 17.57μmolL^(−1) for ***,*** results suggested that *** had a high N demand for growth,and was capable of using wide ranges of N *** strategy of N utilization for *** may make this species an advantage in N-enriched sea areas especially the dissolved organic nitrogen(DON)rich coastal waters,which might be the reason why *** widely distributes in the cosmo-politan coastal and estuarine sea areas.

关键词： Skeletonema costatum Prorocentrum micans Chattonella marina DON half-saturation constant urea

Preparation of nanocrystalline palladium on p-Si by electroless deposition and its photo-electrochemical hydrogen evolution property

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Rare Metals 2006年第3期25卷 241-245页

作者： YAO Suwei li He ZHANG weiguo WANG Hongzhi BEN Yuheng SUGIYAMA Laboratory of Surface Technology School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

The Pd-modified p-Si electrode was prepared by means of electroless deposition. The average diameter of Pd nanoparticles was about 80 nm from SEM observations. XRD results showed that the structure of Pd coatings was nanocrystalline. The catalyzing properties of the Pd-modified p-Si electrode for hydrogen evolution under illumination and in dark were studied with the constant current polarization method. The polarization potential for hydrogen evolution reac- tion （HER） of the Pd/p-Si electrode under illumination was 250 mV lower than that in dark, and was 450 mV lower than that of p-Si in dark at the current density of 2.5 mA·cm^-2. The results of electrochemistry impedance spectra （EIS） showed that electrochemistry HER resistance of the modified electrode under illumination decreased from 593.12 to 442.20 Ω·cm^2, and the HER rate increased evidently.

关键词： electrochemistry Pd-modified p-Si electrode electroless hydrogen evolution reaction

Mechanical property of artificial methane hydrate under triaxial compression

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Journal of Natural Gas Chemistry 2010年第3期19卷 246-250页

作者： Yongchen Song Feng Yu Yanghui li weiguo liu Jiafei Zhao Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian 116024 Liaoning China

Methane production from hydrate reservoir may induce seabed slide and deformation of the hydrate-bearing *** research on mechanical properties of methane hydrate is considered to be important for developing an efficient methane exploitation *** this paper,a triaxial test system containing a pressure crystal device was developed with the conditions to stabilize the hydrate.A series of triaxial shear tests were carried out on artificial methane hydrate *** addition,mechanical characteristics of methane hydrate were studied with the strain rates of 0.1 and 1.0 mm/min,respectively,under the conditions of different temperatures（T =-5,-10,and-20 ℃） and confining pressures（P = 0,5,10,15,and 20 MPa）.The preliminary results show that when the confining pressure was less than 10 MPa,the increase of confining pressure leaded to the enhancement of shear ***,the decreasing temperature and the increasing strain rate both caused the increase in shear strength.

关键词： triaxial mechanical properties confining pressure temperature strain rate

Resistance welding of glass fiber reinforced thermoplastic composite:Experimental investigation and process parameter optimization

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Chinese Journal of Aeronautics 2020年第12期33卷 3469-3478页

作者： Bing DU liming CHEN Houchang liU Qinghao HE Weiming QIN weiguo li College of Aerospace Engineering Chongqing UniversityChongqing 400030China Chongqing Key Laboratory of Heterogeneous Material Mechanics Chongqing UniversityChongqing 400030China Chongqing Key Laboratory of Nano–Micro Composite Materials and Devices School of Metallurgy and Materials EngineeringChongqing University of Science and TechnologyChongqing 401331China Centre for Advanced Materials Technology School of AerospaceMechanical and Mechatronic EngineeringThe University of SydneyNSW 2006Australia

The utilization of fiber reinforced thermoplastics(FRTP)is expected to fulfill lightweight demand in mass-produced aerospace *** the unavoidable assembly of FRTP parts,fusion bonding methods such as resistance welding are promising compared with mechanical joint and adhesive *** this paper,a procedure has been brought out to understand the relationship between processing conditions and performance of the FRTP welding *** adherends were continuous glass fiber reinforced polypropylene(GF/PP)laminates fabricated by hotpressing *** influences of time,current and pressure on the bending strength of the resistance welding joints were investigated.A processing window was drawn based on the optical observation of welded *** quantitative relationship between process parameters and mechanical property of GF/PP welding joint was established by Response Surface Method(RSM)with high *** was found that bending strength of GF/PP welding joint was improved by 31%compared with hot-pressing benchmark.

关键词： Mechanical property Processing parameters Resistance welding Response Surface Method Thermoplastic