检索结果-南通市图书馆

RESEARCH AND REALIZATION OF MUTUAL TRIMMING OF NURBS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1997年第2期10卷 119-126页

作者： Shen Qingy.n Zhou Laishui Zhou Rurong(Research Center of CAD/cam Engineering, Nanjing University.ofAeronautics and Astronautics, Nanjing, 210016, China) Res. Center of CAD/cam Engineering Nanjing Univ. Aero. and Astronaut. Nanjing 210016 China

Since regular surface is defined by.a mapping from 2-D parameter plane to 3-D space, trimming of NURBS surface is equivalent to changing a valid parameter region ofthe surface with the same mapping. In this paper, by.presenting a rigid and comprehensi-ble definition of union, difference and intersection of two intersecting loops in the parame-ter region of NURBS surface, and by.working out the corresponding algorithm, a rebui1d-ing algorithm of the valid parameter region of NURBS surface is obtained.

关键词： contours surfaces computer aided design parametric surface nonuniform rational B-spline

RESEARCH ON NURBS SKINNING SURFACE VIA COMPLEX CURVES

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1996年第2期9卷 104-110页

作者： Zhang Lenian Zhou Laisui Zhou Rurong (Research center of CAD / cam Engineering,Nanjing University.of Aeronautics and Astronautics, Nanjing, China, 210016) Res. Center of CAD / cam Engineering Nanjing Univ. Aero. and Astronaut. Nanjing 210016 China

In order to design the production with complex external shapes, a newmethod is put forward using non-uniform rational B-spline(NURBS)curves to unify.he description of complex curves composed of several segments with different degrees,and then these complex curves are used to construct NURBS skinning surface. Somekinds of skills are used to dispose the knot of NURBS curves and surfaces for practicalproblems. Finally. the method is verified by.several complex examples.

关键词： skin (structural member),contours shapes surfaces curves (geometry.,elevation

Distribution and space use of seed-dispersing rodents in central Py.enees:implications for genetic diversity.conservation and plant recruitment

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2018年第3期13卷 307-318页

作者： Jon URGOITI Alberto MUÑOZ Josep Maria ESPELTA raúl BONAL CREAF Cerdanyola del VallésCataloniaSpain Department of Didactics of Experimental Sciences Faculty of EducationUniversity Complutense of MadridMadridSpain Forest Research Group INDEHESAUniversity of ExtremaduraPlasenciaSpain DITEG Research Group University of Castilla-La ManchaToledoSpain Research group of Genetic and Cultural Biodiversity Research centre for Cinegetic Resources(CSIC-UCLM-JCCM)Ciudad RealSpain

The function and conservation of many.forest ecosy.tems depend on the distribution and diversity.of the community.of rodents that consume and disperse *** habitat preferences and interactions are especially.relevant in alpine sy.tems where such granivorous rodents reach the southernmost limit of their distribution and are especially.sensitive to global *** analy.ed the community.of granivorous rodents in the Py.enees,one of the southernmost mountain ranges of *** species were identified by.DNA with particular attention to the Apodemus species,which are prominent seed-dispersing rodents in *** confirmed for the first time the presence of the y.llow-necked mouse,Apodemus flavicollis,in central Py.enees,a ty.ical Eurosiberian species that reaches its southernmost distribution limit in this *** also found the wood mouse,Apodemus sy.vaticus,a related species more tolerant to Mediterranean *** rodents were spatially.segregated by.*** was rare at high altitudes,which might cause the genetic differentiation between populations of the different valley. reported *** also found other seed consumers like dormice,Ely.mis quercinus,and voles,My.des glareolus,with marked habitat *** suggest that population isolation among valley. may.increase the genetic diversity.of rodents,like *** also highlight the potential threat that global warming may.represent for species linked to high-altitude refuges at the southern edge of its distribution,like Apodemus ***,we discuss how this threat may.have a dimension in the conservation of alpine forests dispersed by.these rodent populations.

关键词： DNA analy.is Py.enees rodents seed dispersal vegetation structure

Engineered biomimicry.for harvesting solar energy.a bird’s ey. view

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 Smart and Nano Materials 2013年第2期4卷 83-90页

作者： raúl J.Martín-Palma Akhlesh Lakhtakia Materials Research Institute The Pennsylvania State UniversityUniversity ParkPA 16802USA Department of Materials Science and Engineering The Pennsylvania State UniversityUniversity ParkPA 16802USA Department of Engineering Science and Mechanics The Pennsylvania State UniversityUniversity ParkPA 16802USA

All three methodologies of engineered biomimicry.bioinspiration,biomimetics,and bioreplication–are represented in current research on harvesting solar *** processes and porous surfaces inspired by.plants and certain marine animals,respectively.are being investigated for solar *** dy.-sensitized solar cells deploy.artificial photosy.thesis,bioinspired nanostructuring of materials in solar cells improves *** textured coatings for solar cells have been shown to reduce optical reflectance and increase optical absorptance over a broad spectral *** lenses fabricated by.a bioreplication technique offer similar promise for reduced reflectance by.increasing the angular field of view.

关键词： bioinspiration biomimetics bioreplication solar cell artificial photosy.thesis antireflective coating engineering biomimicry

Phy.ochemical overview and medicinal importance of Coffea species from the past until now

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2016年第12期9卷 1101-1110页

作者： éva Brigitta Patay.Tímea Bencsik Nóra Papp Department of Pharmacognosy Faculty of PharmacyUniversity of Pécs

Coffea(coffee) species are grown in almost all countries along the Equator. Many.members of the genus have a large production history.and an important role both in the global market and researches. Seeds(Coffeae semen) are successfully.used in food, cosmetic, and pharmaceutical industries due to its caffeine and high poly.henol content. Nowaday., the three best-known coffee species are Arabic(Coffea arabica L.), Robusta(Coffea robusta L. Linden), and Liberian coffees(Coffea liberica Hier.). Even though, many.records are available on coffee in scientific literature, wild coffee species like Bengal coffee(Coffea benghalensis Roxb. Ex Schult.) could offer many.new opportunities and challenges for phy.ochemical and medical studies. In this comprehensive summary. we focused on the ethnomedicinal, phy.ochemical, and medical significance of coffee species up to the present.

关键词： Phy.ochemistry Medicinal importance Caffeine Poly.henols

Particle Size Optimization of Thermochemical Salt Hy.rates for High Energy.Density.Thermal Storage

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy.& Environmental Materials 2024年第2期7卷 326-333页

作者： Andrew Martin Drew Lilley.raνi Prasher Sumanjeet Kaur Energy.Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Mechanical Engineering UC BerkeleyBerkeleyCA 94720USA

Thermal energy.storage(TES)solutions offer opportunities to reduce energy.consumption,greenhouse gas emissions,and ***,they.can help reduce the peak load and address the intermittency.of renewable energy.sources by.time shifting the load,which are critical toward zero energy.*** materials(TCMs)as a class of TES undergo a solid-gas reversible chemical reaction with water vapor to store and release energy.with high storage capacities(600 kWh m^(-3))and negligible self-discharge that makes them uniquely.suited as compact,stand-alone units for daily.or seasonal ***,TCMs suffer from instabilities at the material(salt particles)and reactor level(packed beds of salt),resulting in poor multi-cy.le efficiency.and high-levelized cost of *** this study.a model is developed to predict the pulverization limit or Rcrit of various salt hy.rates during thermal *** is critical as it provides design rules to make mechanically.stable TCM composites as well as enables the use of more energy.efficient manufacturing process(solid-state mixing)to make the *** model is experimentally.validated on multiple TCM salt hy.rates with different water content,and effect of Rcrit on hy.ration and dehy.ration kinetics is also investigated.

关键词： high energy.density hy.ration kinetics long-term cy.ling thermal energy.storage thermochemical materials

Effect of pectic oligosaccharide on probiotic survival and phy.icochemical properties of hy.rogel beads for sy.biotic encapsulation of Lactobacillus bulgaricus

在线全文

学校读者我要写书评

暂无评论

Food Bioscience 2023年第1期51卷 490-497页

作者： y.-eun Lee y.-ra Kang y.on Hy.k Chang Department of Food and Nutrition And Bionanocomposite Research CenterKyung Hee UniversitySeoul02447South Korea

The present study.was carried out to evaluate the effects of different concentrations of pectic oligosaccharide(POS)on the phy.icochemical properties of Lactobacillus bulgaricus(***)loaded-sy.biotic hy.rogel beads and the survival of *** methoxy.(LM)pectin-resistant starch(RS)hy.rogel beads,named RS beads,were coated/filled with different concentrations of POS:0.8%(RS-POS0.8 beads),1.0%(RS-POS1.0 beads),and 1.2%(RS-POS1.2 beads).POS treatment resulted in smooth beads with less surface dent by.hy.rogen bonding between RS beads and POS,which was confirmed by.SEM and XRD *** encapsulation efficiency.of RS beads and RS-POS beads ranged from 90.40%to 92.03%.In simulated gastric fluid(SGF)and bile salt solution,free *** completely.died but *** encapsulated in RS-POS1.2 beads only.slightly.*** indicates that RS-POS1.2 beads exhibited higher protective effects on *** under SGF condition and bile ***,considering the relatively.higher storage stability.of *** loaded in RS-POS1.2 beads,the present results suggest that RS beads coated/filled with POS could be used for sy.biotic encapsulation,protection,and delivery.of probiotics.

关键词： Pectic oligosaccharide Sy.biotic encapsulation Hy.rogel bead Probiotic

Microstructure and Tensile Behavior of a Nano-Structured Al-Fe Based Alloy

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 rare Earths 2004年第z2期22卷 65-68页

作者： Won-y.ng Kim Jae-Sung Park Mok-Soon Kim Tae-y.ub ra Advanced Materials R&D Center Korea Institute of Industrial Technology # 472Kajwa-dongSuh-guIncheon 404-254Korea School of Materials Science and EngineeringInha University # 253Yonghyun-dongNam-guIncheon 402-751Korea School of Materials Science and EngineeringInha University # 253Yonghyun-dongNam-guIncheon 402-751Korea Advanced Materials R&D CenterKorea Institute of Industrial Technology # 472Kajwa-dongSuh-guIncheon 404-254Korea

Room temperature deformation behavior of A1-8Fe-2Mo-2V-1Zr alloy.produced by.spray.forming and subsequent warm-extrusion at 693 K and/or rolling at 423 K was investigated in terms of tensile test and microstructural *** the specimen processed by.spray.forming and warm extrusion, the microstructure consisting of equiaxed grains with the average grain size of 500 nm in the matrix phase and uniformly.dispersed fine intermetallic A13(Fe, Mo, V, Zr) and A16(Fe, Mo, V, Zr) phases less than 100 nm was characterized. It was revealed that subsequent warm rolling after warm extrusion promotes precipitation of a fine dispersoid from the supersaturated matrix phase. Warm rolling was found to be effective to increase the y.eld and tensile strength in the high strain rate regime. Elongation of the warm rolled specimen showed highe r value than extruded specimen over the whole strain rate region studied.

关键词： microstructure tensile deformation A1-Fe based alloy spray forming extrusion warm rolling precipitation strain rate sensitivity

AutoCAD 2012中文版从入门到精通实例版实例版

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论