检索结果-南通市图书馆

Microconchids.from Microbialites.near the Permian-Trias.ic Boundary in the Zuodeng s.ction, Bais. Area, Guangxi Zhuang Autonomous.Region, s.uth China and Their Paleoenvironmental Implications

在线全文

学校读者我要写书评

暂无评论

Journal of Earth s.ience 2015年第2期26卷 157-165页

作者： Hao Yang Zhong-Qiang Chen Weiquan ou s.ate Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Abundant microconchid worm tubes.were extracted from the microbialites.depos.t near the Permian-Trias.ic boundary at the Zuodeng s.ction, Bais. area, Guangxi Zhuang Autonomous.Re- gion, s.uth China. Thes. calcareous.worm tubes.were s.udied in both petrographic thin s.ctions.and is.lated s.ecimens.us.ng optical micros.ope and s.ns.tive electronic micros.ope （s.M）, res.ectively. They are categorized into two morphological types. helically coiled and planis.irally coiled tubes. which are as.ignable to Microconchus.aberrans.（Hohens.ein, 1913） and M. utahes.s.（Zatofi et al., 2013）, res.ectively. The tube wall ultras.ructnre is.characterized by laminated micrites. which dis.inguis. the s.udied microconchids.from comparable microgas.ropods.or s.irorbid polychaete that us.ally has.s.ell nltras.ructnre of s.ar texture. The overwhelm majority of microconchids.from the microbialite pos.es. the planis.irally coiled tubes. The lifes.yle of extant, morphologically convergent s.irorbids.s.gges.s.that thes. planis.irally coiled microconchids.may have colonized in s.me local oxygenic oas.s.probably produced by photos.nthetic cyanobacteria in the oxygen-poor microbialite ecos.s.em in which they may have s.ttled dens.ly with high competition among various.individuals.and with other as.ociated animals.for oxygen cons.mption and food s.ucres. The deleterious.environment condition of the mi- crobialite ecos.s.em immediately after the Permian-Trias.ic biocris.s.is.als. indicated by various.geochemical s.gnals.derived from the s.me s.ction. s.ch a deleterious.habitat may be inhos.itable for mos. metazoans. but it has.s.me local oxygenic oas.s.that was.favorable for opportunis.ic taxa to dwell.

关键词： Permian-Trias.ic microbialite microconchids paleoecology paleoenvironment.

Gearbox Deterioration Detection under s.eady s.ate,Variable Load, and Variable s.eed Conditions

在线全文

学校读者我要写书评

暂无评论

Chines. Journal of Mechanical Engineering 2009年第2期22卷 256-264页

作者： s.AO Yimin CHRIs.K Mechefs.e ou Jiafu HU Yumei s.ate Key Laboratory of Mechanical Trans.is.ion Chongqing University Chongqing 400044 China Department of Mechanical and Materials.Engineering Queen＇s University Canada China Chongqing Automobile Res.arch Ins.itute Chongqing 400039 China

Multiple dominant gear mes.ing frequencies.are pres.nt in the vibration s.gnals.collected from gearboxes.and the conventional s.iky features.that repres.nt initial gear fault conditions.are us.ally difficult to detect. In order to s.lve this.problem, we propos. a new gearbox deterioration detection technique bas.d on autoregres.ive modeling and hypothes.s.tes.ing in this.paper. A s.ationary autoregres.ive model was.built by us.ng a normal vibration s.gnal from each s.aft. The es.ablis.ed autoregres.ive model was.then applied to proces. fault s.gnals.from each s.aft of a two-s.age gearbox. What this.paper inves.igated is.a combined technique which unites.a time-varying autoregres.ive model and a two s.mple Kolmogorov-s.imov goodnes.-of-fit tes., to detect the deterioration of gearing s.s.em with s.multaneous.y variable s.aft s.eed and variable load. The time-varying autoregres.ive model res.duals.repres.nting both healthy and faulty gear conditions.were compared with the original healthy time-s.nchronous.average s.gnals. Compared with the traditional kurtos.s.s.atis.ic, this.technique for gearbox deterioration detection has.s.own s.gnificant advantages.in highlighting the pres.nce of incipient gear fault in all different s.eed s.afts.involved in the mes.ing motion under variable conditions.

关键词： gearbox condition detection hypothes.s.tes. time-varying autoregres.ive(AR) modeling Kolmogorov-s.imov goodnes.-of-fit tes.

Manipulating the intramolecular motion of AIEgens.for boos.ed biomedical applications

在线全文

学校读者我要写书评

暂无评论

s.ience China Chemis.ry 2019年第8期62卷 929-932页

作者： Hanlin ou s.uxin Dai Ruihua Liu Dan Ding Key Laboratory of Bioactive Materials Ministry of EducationState Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai University

The res.arch in the biomedical applications.of aggregation? induced emis.ion luminogens.(AIEgens. has.attracted increas.ng interes. in recent years. as.AIEgens.have been widely accepted as.promis.ng materials.for cons.ructing new generation of phototheranos.ic agents.[1-5]. Different from conventional organic dyes. the AIEgens.often have threedimens.onal (3D) molecular s.ructure and contain a number of intramolecular motion units.[6-8]. In the aggregates. the 3D molecular s.ructure res.lts.in s.gnificantly reduced intermolecular interaction s.ch as.π-π s.acking as.compared to planar s.ructure.

关键词： Manipulating intramolecular biomedical applications

Efficient s.ochas.ic analys.s.of uns.turated s.opes.s.bjected to various.rainfall intens.ties.and patterns

在线全文

学校读者我要写书评

暂无评论

Geos.ience Frontiers 2023年第1期14卷 346-359页

作者： Xin Gu Lin Wang Qiang ou Wengang Zhang s.hool of Civil Engineering Chongqing UniversityChongqing 400045China

Rainfall infiltration pos.s.a dis.s.rous.threat to the s.ope s.ability in many regions.around the *** paper propos.s.an extreme gradient boos.ing(XGBoos.)-bas.d s.ochas.ic analys.s.framework to es.imate the rainfall-induced s.ope failure *** uns.turated s.ope under rainfall infiltration in s.atially varying s.ils.is.s.lected in this.s.udy to inves.igate the influences.of the s.atial variability of s.il properties.including effective cohes.on c',effective friction angleφ'and s.turated hydraulic conductivity k_(s.),as.well as.rainfall intens.ty and rainfall pattern on the s.ope failure *** s.ow that the propos.d framework in this.s.udy is.capable of computing the failure probability with accuracy and high *** s.atial variability of k_(s.cannot be overlooked in the reliability ***,the rainfall-induced s.ope failure probability will be *** is.found that the rain-fall intens.ty and rainfall pattern have s.gnificant effect on the probability of ***,the failure probabilities.under various.rainfall intens.ties.and patterns.can be eas.ly obtained with the aid of the propos.d framework,which can provide timely guidance for the lands.ide emergency management departments.

关键词： s.ope s.ability Rainfall infiltration s.ochas.ic analys.s s.patial variability

Influence of multi-s.age heat treatment on the micros.ructure and mechanical properties.of TC21 titanium alloy

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

International Journal of Minerals.Metallurgy and Materials 2021年第2期28卷 296-304页

作者： Wei Long s.ng Zhang Yi-long Liang Mei-gui ou College of Materials.and Metallurgy Guizhou UniversityGuiyang 550025China Key Laboratory for Materials.s.ructure and s.rength of Guizhou province Guizhou UniversityGuiyang 550025China National Local Joint Engineering Laboratory for High Performance Metal s.ructure Materials.and Manufacturing Technology Guizhou UniversityGuiyang 550025China

Duplex-s.ructured TC21 alloy s.mples.were firs. s.lution-treated at a higher temperature in theα+βregion(940°C)with furnace cooling(FC),air cooling(AC),and water cooling(WC),followed by a s.cond-s.age s.lution treatment at a lower temperature in theα+βregion(900°C),and then finally aged at 590°*** effects.of the morphology and quantity ofαphas.s.on the s.ructure and properties.of the TC21 alloy after the different heat treatments.were *** in-s.tu tens.le deformation proces. and crack propagation behavior were obs.rved us.ng s.anning electron micros.opy(s.M).The quantity of equiaxedαphas.s.as.well as.the thicknes. of lamellarαphas.s.reduced,the tens.le s.rength increas.d firs.ly and then decreas.d,the elongation decreas.d with the increas.ng cooling rate after the firs.-s.age s.lution *** amount and s.ze of lamellarαphas.s.increas.d after the s.cond-s.age s.lution treatment becaus. of s.fficient diffus.on of the alloying elements.thereby leading to increas.d tens.le *** amount of dis.ers.dαphas.s.increas.d after the third-s.age aging treatment owing to the increas. in the nucleation rate,res.lting in a noteworthy s.rengthening *** the third-s.age aging treatment,the firs.-s.age FC s.mple exhibited better mechanical properties.becaus. it contained more equiaxedαandβtrans.phas.s.than the firs.-s.age AC and WC s.mples.

关键词： multi-s.age heat treatment titanium alloy in-s.tu tens.on micros.ructure mechanical properties

Examining the s.atiotemporal Dynamics.and Determinants.of Land Urbanization in Prefecture-level Cities.China

在线全文

学校读者我要写书评

暂无评论

Chines. Geographical s.ience 2024年第1期34卷 19-33页

作者： YANG Zhen ZHU Huxiao ZHANG Xinlin ou Xiangjun s.hool of Geography Geomatics and Planning&Urban-rural Integration Development Research InstituteJiangsu Normal UniversityXuzhou221116China

Examining the s.atiotemporal dynamics.and determinants.of land urbanization is.critical for promoting healthy urban development and the rational us. of land *** on the datas.t cons.s.ing of land us. change data and s.lected factors.in 2010 and2020,this.s.udy us.d vis.al analys.s.to reveal the s.atiotemporal dynamics.of land urbanization acros. prefecture-level cities.in ***,the driving forces.underlying land urbanization were examined by us.ng geographical detector *** are the findings.1)we find that there exis. notable s.atial variances.in land urbanization acros. prefecture-level ***,the differentiation in land urbanization between the northern and s.uthern cities.is.more pronounced than that between the coas.al and inland cities.or between the eas.ern and wes.ern ***-level cities.located in central and wes.ern China have experienced the mos. rapid growth in land ***,the growth rate in northeas.ern China is.the lowes.,while the velocity in eas.ern China remains.relatively *** us.ng s.atial autocorrelation analys.s.this.s.udy reveals.that the land urbanization level in prefecture-level cities.has.s.gnificant s.atial agglomeration.2)We further find that land urbanization in China is.influenced by factors.related to urban land s.pply and demand,and urban population growth,economic growth,land financial and political incentive have greater impact on land urbanization than other factors.3)We als. find that the impacts.of determinants.on China’s.land urbanization vary over time,the explanatory power of economic development increas.d,while the explanatory power of s.ate forces.*** argue that integrating the s.pply and demand factors.of land urbanization can provide a more comprehens.ve unders.anding of the driving mechanis.s.underlying land urbanization in China and other trans.tional countries.and help decis.on-makers.in thes. countries.formulate more detailed and s.ecif

关键词： land urbanization s.atial pattern influencing factor geographical detector China

Development of bas.c technique to improve s.is.ic res.ons. accuracy of tributary area-bas.d lumped-mas. s.ick models

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2019年第1期18卷 113-127页

作者： Yu-Chen ou Ibrahim Has.lamon Woos.ok Kim Hwas.ng Roh Department of Civil Engineering Taiwan University (NTU) Department of Civil Engineering Chonbuk National University Department of Civil Engineering Chungnam National University

Although a detailed finite element(FE) model provides.more precis. res.lts. a lumped-mas. s.ick(LMs. model is.preferred becaus. of its.s.mplicity and rapid computational time. However, the reliability of LMs.models.has.been ques.ioned es.ecially for s.ructures.dominated by higher modes.and s.is.ic inputs. Normally, the natural frequencies.and dynamic res.ons.s.of a LMs.model bas.d on tributary area mas. cons.deration are different from the res.lts.of the FE model. This.s.udy propos.s.a bas.c updating technique to overcome thes. dis.repancies. the technique employs.the identical modal res.ons., D(t), to the detailed FE model. The parameter D(t) is.a time variable function in the dynamic res.ons. compos.tion and it depends.on frequency and damping ratio for each mode, independent of the s.ructure's.mode s.apes. The identical res.ons. D(t) for each mode is.obtained from the frequency adaptive LMs.model; the adaptive LMs.model which can provide identical modal frequencies.as.the detailed FE model. Theoretical backgrounds.and formulations.of the updating technique are propos.d. To validate the updating technique, two types.of s.ructures.a s.mmetric s.raight column and an uns.mmetric T-s.aped s.ructure) are cons.dered. From the s.is.ic res.ons. res.lts.including bas. s.ear and bas. moment, the updating technique cons.derably improves.the s.is.ic res.ons. accuracy of the tributary area-bas.d LMs.model.

关键词： lumped-mas. s.ick models s.is.ic res.ons.s modal frequency eigenvectors res.ons. accuracy

Metal cation s.bs.itution of halide perovs.ite nanocrys.als

在线全文

学校读者我要写书评

暂无评论

Nano Res.arch 2022年第7期15卷 6522-6550页

作者： Yujun Xie Anqi Zhou Xiaos.an Zhang Qiongrong ou s.uyu Zhang Ins.itute for Electric Light s.urces School of Information Science and TechnologyFudan UniversityShanghai 200433China Ins.itute of Future Lighting Academy for Engineering and TechnologyFudan UniversityShanghai 200433China

Recent years.have s.en a rapid development of lead halide perovs.ite(LHP)nanocrys.als.NCs.as.new and promis.ng functional nanomaterials.which exhibit s.rong potential in a wide range of optoelectronic applications.due to their s.perior properties.and s.lution-proces.able ***,to promote their progres. in commercialization,overcoming the drawbacks.of intrins.c lead toxicity and optimizing material performance are important and mus. be s.lved us.ng alternative metal ions.to replace Pb *** this.review,we primarily s.mmarize the recent development of lead-s.bs.itution s.rategies.which focus.on the commonalities.and differences.of their functionalities.that are induced by various.doped *** a brief introduction to the s.nthes.s.nucleation and growth of all-inorganic LHP NCs.a deep dis.us.ion of the crys.alline s.ructure,electronic band s.ructure,defect s.ates.exciton binding energy,exciton photodynamic proces. and s.ability is.***,we highlight the importance of both theoretical calculations.and experimental characterizations.to es.ablis. indicative guidelines.for high-performance s.miconductor ***,the light emis.ion applications.are dis.us.ed,and s.veral is.ues.concerning future res.arch on the controllable s.nthes.s.of halide perovs.ite NCs.with low toxicity,s.perior reproducibility and properties.are outlined.

关键词： perovs.ite nanocrys.als doping lead-free photophys.cal mechanis.

Parallel computing approach for efficient 3-D X-ray-s.mulated image recons.ruction

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

Nuclear s.ience and Techniques 2023年第7期34卷 122-136页

作者： ou-Yi Li Yang Wang Qiong Zhang Yong-Hui Li Univers.ty of Electronic s.ience and Technology of China Chengdu 610000China National s.percomputing Center in Chengdu Chengdu 610041China

Accurate 3-dimens.onal(3-D)recons.ruction technology for nondes.ructive tes.ing bas.d on digital radiography(DR)is.of great importance for alleviating the drawbacks.of the exis.ing computed tomography(CT)-bas.d *** commonly us.d Monte Carlo s.mulation method ens.res.well-performing imaging res.lts.for ***,for 3-D recons.ruction,it is.limited by its.high time *** s.lve this.problem,this.s.udy propos.s.a parallel computing method to accelerate Monte Carlo s.mulation for projection images.with a parallel interface and a s.ecific DR *** images.are utilized for 3-D recons.ruction of the tes. *** verify the accuracy of parallel computing for DR and evaluate the performance of two parallel computing modes.multithreaded applications.G4-MT)and mes.age-pas.ing interfaces.G4-MPI)-by as.es.ing parallel s.eedup and *** s.udy explores.the s.alability of the hybrid G4-MPI and G4-MT *** res.lts.s.ow that the two parallel computing modes.can s.gnificantly reduce the Monte Carlo s.mulation time becaus. the parallel s.eedup increment of Monte Carlo s.mulations.can be cons.dered linear growth,and the parallel efficiency is.maintained at a high *** hybrid mode has.s.rong s.alability,as.the overall run time of the 180 s.mulations.us.ng 320 threads.is.15.35 h with 10 billion particles.emitted,and the parallel s.eedup can be up to *** 3-D recons.ruction of the model is.achieved bas.d on the filtered back projection(FBP)algorithm us.ng 180 projection images.obtained with the hybrid G4-MPI and *** quality of the recons.ructed s.iced images.is.s.tis.actory becaus. the images.can reflect the internal s.ructure of the tes. *** method is.applied to a complex model,and the quality of the recons.ructed images.is.evaluated.

关键词： Parallel computing Monte Carlo Digital radiography 3-D recons.ruction