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The Kirkendall effect on erosion resistance of chrome-coated 25Cr3Mo2WNiV and 30SiMn2MoV gun barrel steels

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journal of Materials Science & Technology 2024年第10期177卷 246-255页

作者： C.H.Dou P.f.jin C.Z.Wang j.j.Li C.Zhang j.f.Huang C.Zhang Key Laboratory for Advanced Materials Processing State State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China National joint Engineering Research Center for Abrasion Control and Molding of Metal Materials School of Materials Science and EngineeringHenan University of Science and TechnologyLuoyang 471003China

This study aimed to investigate the erosion behavior and mechanism of a newly developed 25Cr3Mo2WNiV steel with a chrome coating using promoted ignition combustion *** erosion threshold pressure and temperature of the chrome-coated 25Cr3Mo2WNiV steel were determined to be 0.2 MPa and 254.3 K higher than those of traditional chrome-coated 30SiMn2MoV ***,Kirkendall voids and inter-diffusion between the Cr coating and matrix were first observed before *** improved erosion resistance of the chrome-coated 25Cr3Mo2WNiV steel was attributed to the suppression of the Kirkendall effect,which minimized heat generation at the Cr/matrix interface by pre-venting oxygen diffusion and reducing oxygen affinity.

关键词： Erosion resistance Kirkendall effect Cr coating Gun steel

Interactive data styling and multifocal visualization for a multigrid web-based Digital Earth

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International journal of Digital Earth 2021年第3期14卷 288-310页

作者： M.j.Sherlock M.Hasan f.f.Samavati Department of Computer Science University of CalgaryCalgaryCanada

Globe-based Digital Earth(DE)is a promising system that uses 3D models of the Earth for integration,organization,processing,and visualization of vast multiscale geospatial *** growing size and scale of geospatial datasets present significant obstacles to interactive viewing and meaningful visualizations of these DE *** address these challenges,we present a novel web-based multiresolution DE system using a hierarchical discretization of the globe on both server and client *** presented web-based system makes use of a novel data encoding technique for rendering large multiscale geospatial datasets,with the additional capability of displaying multiple simultaneous *** the data needed for the current views and scales are encoded and *** leverage the power of GPU acceleration on the client-side to perform real-time data rendering and dynamic *** rendering of multiple views allows us to support multilevel focus+context visualization,an effective approach to navigate through large multiscale global *** client–server interaction as well as the data encoding,rendering,styling,and visualization techniques utilized by our presented system contribute toward making DE more accessible and informative.

关键词： Digital Earth Discrete Global Grid System data integration data fusion multilevel focus+context visualization spatial resolution context awareness

Topsoil as Affected by Dung Deposition Under Resting Places of Red Howler Monkey (Alouatta seniculus)

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Pedosphere 2008年第6期18卷 691-698页

作者： S. POUVELLE f. fEER j. f. PONGE Musum National d'Histoire Naturelle CNRS UMR 7179 4 avenue du Petit-Chateau

The short-term influence of dung deposition and the further redistribution of dung by dung beetles were studied under a resting place of the red howler monkey （Alouatta seniculus） living in tropical ralnforests of South America. Monkey dung was experimentally clumped on the field in a place used by troops of howler monkeys for resting in the Nouragues Reserve Station, french Guiana. Dung-treated plots were sampled serially over three weeks and compared with controls located in their immediate vicinity. The composition of the soil matrix （top 10 cm） was studied in successive microlayers using an optical method. Under the influence of dung beetle activity, the topsoil became more homogeneous by losing its litter, its content in earthworm faeces increased in the course of time, and surface mineral deposits were penetrated by roots. The results were interpreted in the light of present knowledge on the effects of soil animal activity on plant growth and survival of seedlings.

关键词： dung beetle activity earthworm faeces roots tropical ralnforests

Optimal field development and production design for unconventional reservoirs:A case study from Central Sub-Basin,Permian Basin,New Mexico

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Petroleum Research 2021年第1期6卷 66-76页

作者： Alexander Davis Oladoyin Kolawole marshall Watson Chioma Onwumelu Bob L.Herd Department of Petroleum Engineering Texas Tech University807 Boston AvenueLubbockTXUSA Harold Hamm School of Geology and Geological Engineering University of North DakotaGrand ForksNDUSA

The planning and developmental decisions succeeding the discovery of an unconventional oil and gas field is of utmost importance in attaining successful exploitation and production from these tight *** development and production of hydrocarbon from these unconventional reservoirs require requires adequate planning and execution which could be challenging,due to the sequence of heterogeneous lithologies of these *** this study,we designed and presented a comprehensive field development and production program that is representative of the unconventional oil and gas development in the Central sub-basin of the Permian *** design and achieve optimal field development and production for unconventional reservoirs in the Central sub-basin of the Permian Basin,New Mexico,we utilized field data from an oil and gas well that was drilled to a TVD/MD of 2290 m with a PBTD of 2270 ***,we conducted the petrophysical evaluation of the logs and utilized a decline curve analysis for reservoir evaluation of all the members of the *** also designed and developed comprehensive drilling,completions,and facilities ***,we incorporated an economic analysis of our optimized field development and production *** results provide a valuable plan and critical decision-making insight for optimizing field development and production of unconventional reservoirs in the Permian Basin and across the world.

关键词： Unconventional reservoir Carbonate Permian basin field development Hydrocarbon production

Higher platelet P-selectin in male patients with inflammatory bowel disease compared to healthy males

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World journal of Gastroenterology 2006年第8期12卷 1270-1272页

作者： j Patrik fgerstam Per A Whiss Division of Radiology Department of Medicine and CareFaculty of Health SciencesLinkping UniversityLinkpingSweden Division of Pharmacology Department of Medicine and CareFaculty of Health SciencesLinkping UniversityLinkpingSweden

AIM： To observe if the total amount of platelet P-selectin （tP-selectin） in patients with inflammatory bowel disease （IBD） was related to disease entity or activity, 5-aminosalicylic acid （5-ASA） medication or gender. METHODS： tP-selectin was measured by immunoassay in seventeen IBD patients and twelve healthy controls. RESULTS： Compared to controls, there was no difference of tP-selectin in patients related to disease entity or activity and 5-ASA medication. When the groups were split according to gender the male patient group showed higher levels of tP-selectin compared to male controls （153 ng/mL vs 94 ng/mL, P〈 0.05）. CONCLUSION： Increased tP-selectin levels may alter the inflammatory response and susceptibility to thromboembolic disease. As previously shown with soluble P-selectin, tP-selectin shows gender dependent differences important to consider in future studies.

关键词： Platelet P-selectin Inflammatory bowel disease 5-aminosalicylic acid Gender

On the analytical solution of transient friction in channel flows

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1447-1466页

作者： f.j.GARCíA-GARCíA P.fARINAS-ALVARINO Department of Naval&Industrial Engineering Polytechnic School of EngineeringUniversity of A CorunaCampus Industrial de FerrolFerrol 15403A CorunaSpain Integraciones Técnicas de Seguridad S.A.Pol.Ind.Espiritu SantoC/Nobel15Cambre 15650A CorunaSpain

The transient friction in channel mean flows is the sum of two contributions,i.e.,the underlying laminar flow(ULf)and the purely turbulent component(PTC),and the contributions are analyzed separately by theoretical *** is found that,the transient friction may be higher or remarkably lower than that in equal-Reynolds number steady-state *** universal time constant for plane-parallel laminar flows is reported,and the role of the time constant in a turbulent mean flow is *** is shown that the time constant is related to the turbulence's frozen ***,a study of the logarithmic layer during the transient flow is accomplished,which shows that the logarithmic layer is destroyed.

关键词： transient friction transient flow unsteady channel flow

A review of development of better prediction equations for blast fragmentation

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journal of Rock Mechanics and Geotechnical Engineering 2019年第5期11卷 1094-1109页

作者： f.Ouchterlony j.A. Sanchidrián Department of Mining Engineering and Mineral Economics Montanuniversitaet Leoben Leoben Austria ETSI Minas Universidad Politécnica de Madrid Madrid Spain

The paper reviews the development of prediction formulas for the fragmentation from bench *** attention has been paid to the Kuz-Ram model,its development and errors,and the mean *** *** work by the US Bureau of Mines(USBM)and Chung and Katsabanis are also reviewed,as well as the two julius Kruttschnitt Mineral Research Centre(jKMRC)models,*** crush zone model(CZM)and the two-component model(TCM),which were developed to cope with the underestimation of blasting *** change brought by the Swebrec distribution and the associated Kuznetsov-Cunningham-Ouchterlony(KCO)model is *** distribution-free fragment sizes xP for an arbitrary mass passing P led to the discovery of the fragmentation-energy fan,and with the help of dimensional analysis,to the new fragmentation prediction model xP-frag,which has much lower errors than those of the Kuz-Ram and CZM models.

关键词： Bench blasting Rock fragmentation fragmentation model Size distribution Swebrec function fragmentation-energy fan

Optimal distribution of active piezoelectric elements for noise attenuation in sandwich panels

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International journal of Smart and Nano Materials 2020年第4期11卷 400-416页

作者： j.f.A.Madeira A.L.Araujo IDMEC Instituto Superior TecnicoUniversidade de LisboaLisboaPortugal ADM ISELInstituto Politecnico de LisboaLisboaPortugal

In this paper,a multiobjective optimization approach for obtaining the optimal distribution of surface-bonded piezoelectric sensors and actua-tors for noise attenuation in sandwich panels is *** noise attenuation is achieved by using negative velocity feedback control with co-located sensors and *** control gains are also optimized in order to obtain the most efficient noise attenuation in a given frequency *** in-house implementation of a viscoelastic soft core sandwich plate finite element,including surface-bonded piezoelectric sensors and actuators with active control capabilities,is used for obtaining the frequency response of the *** sound transmission capability of the panels is evaluated using the radiated sound power,along with the Rayleigh integral approach,which is suitable for lightly coupled structural/acoustic *** Direct MultiSearch(DMS)optimization algorithm is used to minimize the added weight due to the piezoelectric material,minimizing also the number of required controllers and maximizing the noise *** total length of the radiated sound power curve is shown to be an effective measure of noise attenuation in a given frequency ***-off Pareto fronts and the obtained optimal configurations are presented and discussed.

关键词： Sandwich structures piezoelectricity viscoelasticity active damping multiobjective optimization

Land use effects on climate in China as simulated by a regional climate model

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Science China Earth Sciences 2007年第4期50卷 620-628页

作者： j.S.PAL f.GIORGI The Abdus Salam International Center for Theoretical Physics Trieste 34100 Italy

A regional climate model (RegCM3) nested within ERA40 re-analyzed data is used to investigate the climate effects of land use change over China. Two 15-year simulations (1987―2001), one with current land use and the other with potential vegetation cover without human intervention, are conducted for a domain encompassing China. The climate impacts of land use change are assessed from the difference between the two simulations. Results show that the current land use (modified by anthropogenic ac- tivities) influences local climate as simulated by the model through the reinforcement of the monsoon circulation in both the winter and summer seasons and through changes of the surface energy budget. In winter, land use change leads to reduced precipitation and decreased surface air temperature south of the Yangtze River, and increased precipitation north of the Yangtze River. Land use change signifi- cantly affects summer climate in southern China, yielding increased precipitation over the region, de- creased temperature along the Yangtze River and increased temperature in the South China area (south-end of China). In summer, a reduction of precipitation over northern China and a temperature rise over Northwest China are also simulated. Both daily maximum and minimum temperatures are affected in the simulations. In general, the current land use in China leads to enhanced mean annual precipitation and decreased annual temperature over south China along with decreased precipitation over North China.

关键词： land use China simulation regional climate model regional climate change