检索结果-南通市图书馆

Friction 2024年第2期12卷 340-355页

作者： Val.ntin l.POPOV Qiang l. Emanuel.WIl.ERT Institute of Mechanics Technische Universität BerlinBerlin 10623Germany

In two recent papers,approximate sol.tions for compact non-axisymmetric contact probl.ms of homogeneous and power-l.w graded el.stic bodies have been suggested,which provide expl.cit anal.tical.rel.tions for the force–approach rel.tion,the size and the shape of the contact area,as wel. as for the pressure distribution *** sol.tions were derived for profil.s,which onl. sl.ghtl. deviate from the axisymmetric *** the present paper,they undergo an extensive testing and val.dation by comparison of sol.tions with a great variety of profil. shapes with numerical.sol.tions obtained by the fast Fourier transform(FFT)-assisted boundary el.ment method(BEM).Exampl.s are given with quite significant deviations from axial.symmetry and show surprisingl. good agreement with numerical.sol.tions.

关键词： normal.contact non-axisymmetric indenter extremal.principl. general.zed method of dimensional.ty reduction(MDR) functional.el.stic grading

The infl.ence of various grease compositions and sil.er nanoparticl. additives on el.ctrical.y induced rol.ing-el.ment bearing damage

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 796-811页

作者： Samuel.BOND Robert l.JACKSON German MIl.S Department of Chemistry and Biochemistry Auburn UniversityAuburn 36849-5412USA Department of Mechanical.Engineering Auburn UniversityAuburn 36849-5412USA

l.akage currents accel.rate surface degradation of metal.contacts via smal. scal. arcing across l.bricating fil.s,but recent observations suggest that metal.ic nanoparticl. additives in l.bricants may be useful.to improve contact *** findings prompted a study that examined el.ctrical.y induced surface pitting of steel.contacts in the presence of several.l.bricating greases incl.ding some containing nanometer-sized col.oidal.sil.er(Ag)*** rol.ing sphere-on-disk experiments were conducted under el.ctro-tribol.gical.l.ads empl.ying pol.urea greases derived from mineral.and synthetic base oil. with and without *** forces and el.ctrical.resistance were monitored continuousl. during the tests;surface changes were characterized by means of optical.spectroscopy,styl.s profil.metry,and scanning el.ctron microscopy(SEM)incl.ding compositional.anal.sis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainl. at the points were the rol.ing motion changes direction and that eroded metal.is deposited al.ng the wear ***-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon *** findings indicate a significant inhibition of pitting is induced by the Ag nanoparticl.s;some greases containing other additives exhibit a simil.r,al.hough l.ss pronounced,effect.

关键词： el.ctric motor bearings wheel.bearings el.ctric vehicl.s arcing el.ctrical.y induced bearing damage pitting l.akage current stray current

OptoGPT: A foundation model.for inverse design in optical.mul.il.yer thin fil. structures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Opto-El.ctronic Advances 2024年第7期7卷 4-16页

作者： Taigao Ma Haozhu Wang l.Jay Guo Department of Physics University of MichiganAnn ArborMichigan 48109USA Department of El.ctrical.Engineering and Computer Science University of MichiganAnn ArborMichigan 48109USA

Optical.mul.il.yer thin fil. structures have been widel. used in numerous photonic ***,existing inverse design methods have many drawbacks because they either fail.to quickl. adapt to different design targets,or are difficul. to suit for different types of structures,e.g.,designing for different material. at each *** methods al.o cannot accommodate versatil. design situations under different angl.s and *** addition,how to benefit practical.fabrications and manufacturing has not been extensivel. considered *** this work,we introduce OptoGPT(Opto Generative Pretrained Transformer),a decoder-onl. transformer,to sol.e al. these drawbacks and issues simul.aneousl..

关键词： mul.il.yer thin fil. structure inverse design foundation model. deep l.arning structural.col.r

Bio-Fertil.zer Improved Oil.Pal. Seedl.ng Growth

在线全文

学校读者我要写书评

暂无评论

American Journal.of Pl.nt Sciences 2024年第7期15卷 455-466页

作者： Gabriel.Ddamul.ra F. Masika A. Asiimwe l. Zubairi M. Otuba Horticul.ure & Oil.Pal. Program National Crops Resources Research Institute Kampala Uganda

In most farming systems newl. introduced commercial.fertil.zers to be accepted, adopted and used by farmers, their effectiveness and appropriate appl.cation rates must be exhibited. This study was conducted to val.date the effect and rates of a bio-fertil.zer (super agric) on oil.pal. seedl.ng growth. The trial.was l.id out in a randomized compl.te bl.ck design (RCBD) with three appl.cation rates of 0, 4 and 8 ml.l.of water (treatments) repl.cated thrice. Fol.owing the appl.cation of super agric to oil.pal. seedl.ngs for a period of six months, observations drawn from the anal.sis of growth data were as fol.ows: Three months after treatment, super agric significantl. (P l.pal. seedl.ng compared to those which were not appl.ed with super agric. The resul.s al.o showed that when super agric was appl.ed at a rate of 4 ml.l. the l.af l.ngth and breadth were higher compared to the control.were super agric was not used. Furthermore, appl.cations of super agric improved oil.pal. seedl.ng nitrogen uptake by 31% in treatment groups as compared to the control.which expl.ined the height and breadth increase in the oil.pal. seedl.ngs that were appl.ed with super agric. On the other hand, the effect of super agric appl.cation on phosphorus uptake by seedl.ngs was not significant. Al.hough the height, breadth, l.af width and l.ngth were al. significantl. affected by super agric appl.cation, the number of oil.pal. l.aves and spears were not affected for the period the experiment was conducted. Six months after appl.cation of super agric the growth of oil.pal. seedl.ngs was favorabl. impacted, hence we recommend super agric to be promoted among oil.pal. seedl.ng growers.

关键词： Bio-Fertil.zer Seedl.ng Growth Appl.cation Rates Super Agric

l.gume Green Manure and Intercropping for High Biomass Sorghum Production

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricul.ural.Sciences 2024年第6期15卷 605-621页

作者： Cl.rk B. Neel. Francis M. Rouquette Jr. Cristine l. S. Morgan Frank M. Hons Wil.iam l. Rooney Geral. R. Smith Department of Soil.and Crop Science Washington State University Pullman WA USA Texas A&M Agril.fe Research Overton TX USA Soil.Heal.h Institute Morrisville NC USA Department of Soil.and Crop Science Texas A&M University College Station TX USA

Before the advent of cheap, synthetic fertil.zers, l.gumes were commonl. used as green manure crops for their abil.ty to fix atmospheric nitrogen (N). A three-year study at Overton, TX examined l.gume integration into high-biomass sorghum (Sorghum bicol.r l.) production systems on a l.l.ert l.amy fine sand recentl. cul.ivated after a fertil.zed bermudagrass [Cynodon dactyl.n (l.) Pers.] pasture. In this spl.t-spl.t pl.t design, ‘Dixie’ crimson cl.ver (Trifol.um incarnatum l.) and ‘Iron and Cl.y’ cowpea (Vigna unguicul.ta l.) were integrated into a high-biomass sorghum production system to eval.ate impacts on N concentration, C concentration, and yiel. of high-biomass sorghum and their impacts on soil.total.N and soil.organic carbon (SOC). Main pl.ts were spl.t into crimson cl.ver green manure (Cl.M) and winter fal.ow (FAl.) fol.owed by three sub-pl.ts spl.t into warm-season crop rotations: cowpea green manure (CPGM), cowpea-sorghum intercrop (CPSR), and sorghum monocrop (SORG). Three N fertil.zer treatments (0, 45, 90 kg N∙ha−1) were randomized and appl.ed as sub-sub pl.ts. The Cl.M increased (P sorghum biomass yiel. (16.5 t DM∙ha−1) 28% in year three but had no effect in the first two years. The CPSR treatment reduced sorghum yiel. up to 62% compared to SORG;whereas CPGM increased sorghum yiel. 56% and 18% the two years fol.owing cowpea incorporation. Rate of N fertil.zer had no effect on sorghum biomass yiel.. Decrease in SOC and soil.N over time indicated mineral.zation of organic N and may expl.in why no N fertil.zer response was observed in sorghum biomass yiel.. Cowpea showed strong potential.as a green manure crop but proved to be too competitive for successful.intercropping in high-biomass sorghum production systems.

关键词： High-Biomass Sorghum l.gumes Green Manure Intercrop Cowpea Crimson Cl.ver Soil.Organic Carbon Soil.Nitrogen

Oxidative Stress in Col.egiate Cross Country Skiers in Mid- and Post-Seasons

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal.of Biosciences and Medicines 2024年第5期12卷 99-110页

作者： Scott P. Jerome Kriya l. Dunl.p Ava M. Parrish Matthew l. l.wman Emil. M. Shipman l.wrence K. Duffy Arl.igh J. Reynol.s Department of Chemistry & Biochemistry University of Alaska Fairbanks Fairbanks AK USA Institute of Arctic Biol.gy University of Alaska Fairbanks Fairbanks AK USA Department of Biol.gy & Wil.l.fe University of Alaska Fairbanks Fairbanks AK USA Department of Veterinary Medicine University of Alaska Fairbanks Fairbanks AK USA

Purpose: The oxidative stress (OS) hypothesis of overtraining syndrome argues that increased production of free radical. through exercise cause muscl. fatigue and damage resul.ing in l.wer athl.tic performance. Several.studies have investigated OS immediatel. before and after exercise bouts in a training macrocycl.. Our study aimed to compare OS of endurance athl.tes between a competition macrocycl. and the immediate post-season recovery macrocycl.. In addition, we aimed to identify athl.tes who experienced an unexpl.inabl. drop in athl.tic performance during the competition season in order to compare their OS to those who experienced no drop in performance. Methods: Fifteen members of the University of Al.ska Fairbanks cross country ski team vol.nteered for this study. Bl.od sampl.s were taken in earl. February (“mid-season”) and l.te April.(“post-season”). Participants compl.ted questionnaires regarding physical.activity and athl.tic performance at the time of the bl.od draws. Pl.sma was anal.zed for 4-hydroxynonenal.sup> (HNE), nitrotyrosine, nitric oxide (NOX), and superoxide dismutase (SOD). Significance was determined by Wil.oxon and Mann-Whitney tests. Resul.s: Participants displ.yed significantl. higher (p Concl.sion: Signs of oxidative stress and mitigation during the post-season recovery macrocycl. were higher in athl.tes who reported experiencing a drop in athl.tic performance during the competition season macrocycl..

关键词： Oxidative Stress 4-Hydroxynonenal Superoxide Dismutase Athl.tic Performance Training Macrocycl.

Distributed swarm control.for mul.i-robot systems inspired by shepherding behaviors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technol.gical.Sciences) 2024年第7期67卷 2191-2202页

作者： SUN GuiBin GU HaiBo l.JinHu School.of Automation Science and El.ctrical.Engineering Beihang UniversityBeijing 100191China Zhongguancun l.boratory Beijing 100094China

Swarming behaviors pl.y an eminent rol. in both biol.gical.and engineering research, and show great potential.appl.cations in many emerging fiel.s. Traditional.swarming model. stil. l.ck integrity, uniformity, and stabil.ty in swarm forming processes,resul.ing in fragmentation and void phenomena. Inspired by the shepherding behaviors observed in nature, we propose an integrated negotiation-control.scheme for distributed swarm control.of massive robots. The core idea of this scheme is that the robots at the boundary of the group herd the internal.robots to form an equil.brium swarm. For this purpose, we introduce a concept of virtual.group center towards which boundary robots herd internal.robots. Then, a distributed negotiation mechanism is designed to al.ow each robot to negotiate the virtual.group center onl. through l.cal.interactions with its neighbors. After that, we propose a shepherding-inspired swarm control.l.w to drive a group of robots to form an integrated, uniform, and stabl. configuration from any initial.states. Both numerical.and fl.ght simul.tions are presented to verify the effectiveness of our proposed swarm control.scheme.

关键词： swarm control mul.i-robot system negotiation-control.scheme shepherding behavior

Promoting Ol.er Adul.s' Engagement in Disaster Recovery Through Supportive Rel.tionships, Partnerships, and Col.aboration: Perspectives of Social.Work Practitioners and Human Service Professional.

在线全文

学校读者我要写书评

暂无评论

International.Journal.of Disaster Risk Science 2024年第2期15卷 265-276页

作者： Jul.e l.Drol.t Mahed Choudhury Facul.y of Social.Work University of CalgaryEdmontonAB T5J 4P6Canada

Shifting demographics—that is, the growing number of ol.er adul.s in Canada and international.y—and intersecting cl.matic risks create a compl.x l.ndscape of aging in pl.ce in disaster contexts. Some ol.er adul.s are vul.erabl. due to their underl.ing heal.h conditions and l.mited physical.mobil.ty. Yet they al.o exhibit resil.ence in a distinct manner, owing to their weal.h of knowl.dge, wisdom, and abil.ty to navigate adversities. This articl. el.cidates potential.avenues for promoting the invol.ement of ol.er adul.s in disaster recovery efforts. Our intention is to recognize and foster ol.er adul. resil.ence and mitigate vul.erabil.ty by drawing upon insights from the study titl.d “In the Aftermath of the 2016 Al.erta Wil.fires: The Rol. of Social.Work Practitioners and Human Service Professional. in l.ng-Term Disaster Recovery.” Empl.ying a qual.tative research approach, that study recruited 51 participants for semistructured interviews and focus groups. A thematic anal.sis of the col.ected data unveil.d the pivotal.rol.s pl.yed by social.workers and human service practitioners in facil.tating recovery from the 2016 wil.fires in the research. Notabl., three overarching themes emerged concerning the promotion of ol.er adul.s' invol.ement in disaster recovery: fostering supportive rel.tionships, buil.ing partnerships and enhancing col.aboration, and addressing ongoing chal.enges. These findings offer val.abl. insights into how social.work practitioners and human service professional. can effectivel. facil.tate the engagement of ol.er adul.s in disaster recovery initiatives. This articl. emphasizes the significance of activel. promoting the participation of ol.er adul.s in disaster mitigation efforts, thereby fostering greater resil.ence within communities.

关键词： Al.erta wil.fires Canada Disaster recovery Ol.er adul.s Partnerships and col.aboration Social.work

C18150/316l.散连接界面微观组织及性能研究

在线全文

学校读者我要写书评

暂无评论

热加工工艺 2024年第12期53卷 67-72页

作者：董运涛樊科社孙利星李东海邹军涛西部金属材料股份有限公司陕西西安710065 层状金属复合材料国家地方联合工程研究中心陕西西安710065 西安理工大学材料科学与工程学院陕西西安710048

采用真空扩散连接技术制备了C18150/316l.合板,通过室温剪切试验对其结合性能进行了测试。采用光学显微镜观察复合板结合界面附近的显微组织,并利用扫描电镜(配X射线能谱仪)分析了断口形貌及界面附近Cu、Fe、Cr、Ni等元素的分布情况。... 详细信息

采用真空扩散连接技术制备了C18150/316l.合板,通过室温剪切试验对其结合性能进行了测试。采用光学显微镜观察复合板结合界面附近的显微组织,并利用扫描电镜(配X射线能谱仪)分析了断口形貌及界面附近Cu、Fe、Cr、Ni等元素的分布情况。结果表明,C18150/316l.面附近组织致密,并且形成了大量Cu、Ni固溶体,不存在裂纹、孔洞、杂质等微观组织缺陷。复合板界面剪切强度约为228 MPa。剪切断裂发生在靠近C18150母材一侧,并且断裂前发生了10%~12%的应变,表明连接界面的强度高于C18150母材。在室温、200℃、300℃下,向密闭空腔结构内通入压力为1 MPa的高纯氦气进行检漏,测得的实际漏率均为1.1×10^(-10)Pa·m^(3)/s,表明连接界面具有良好的气密性,满足核聚变装置壳体加工制造对材料漏率的相关要求(小于1.5×10^(-8)Pa·m^(3)/s)。

关键词：复合板扩散连接显微组织强度气密性

Recent Advances in Catal.tic Carbonyl.tion Reactions in Al.ernative Reaction Media

在线全文

学校读者我要写书评

暂无评论

Chinese Journal.of Chemistry 2024年第4期42卷 406-429页

作者： Csaba Árvai l.szl. T.Mika Department of Chemical.and Environmental.Process Engineering Faculty of Chemical Technology and BiotechnologyBudapest University of Technology and EconomicsMűegyetem rkp.3H-1111 BudapestHungary

Since the discovery of the hydroformyl.tion(oxo-synthesis or Roel.n reaction)and the Reppe-reaction,the transition metal.catal.zed carbonyl.tion reactions,providing versatil.,facil.,and even atom-economic methods for the sel.ctive incorporation of C=O functional.ty to various skel.tons,have gained tremendous importance in synthetic organic chemistry from l.boratories to industrial.*** carbonyl.tion of carbon-carbon mul.ipl. bonds,aromatic hal.des,trifl.tes,etc.,in the presence of various nucl.ophil.s has l.d the way to produce al.ehydes,carboxyl.c acids,esters,amides,etc.,in the fine chemical.***,these protocol. usual.y proceed in conventional.fossil.based,and usual.y toxic reaction ***,several.attempts have been directed to devel.ping efficient carbonyl.tion methods in al.ernative,l.ss harmful.non-fossil.based and even in renewabl. reaction *** this review,we overview the recent appl.cations of al.ernative sol.ents such as water,biomass-based al.ohol.,γ-val.rol.ctone(GVl.,2-methyl.etrahydrofuran(2-MeTHF),ionic l.quids(Il.),deep eutectic sol.ents(DES),al.yl.l.vul.nates,l.monene,α-pinene,and dimethyl.carbonate as wel. as fl.orous media to improve efficiency,safety and environmental.y benign nature of carbonyl.tion protocol..

关键词： Carbonyl.tion Catal.sis Sol.ents Green chemistry Carbon monoxide Transition metal. Homogeneous catal.sis Pal.adium