检索结果-南通市图书馆

Influence of Turbulators in Blade cooling p.ssages on Film Hole Discharge coefficients

在线全文

学校读者我要写书评

暂无评论

j.urnal of Thermal Science 2004年第3期13卷 245-254页

作者： H.-p. ScHIFFER j. TAEGE F. HASELBAcH Rolls-Royce Deutschland Eschenweg 11 D-15827 Dahlewitz GermanyRolls-Royce Deutschland Eschenweg 11 D-15827 Dahlewitz GermanyRolls-Royce Deutschland Eschenweg 11 D-15827 Dahlewitz Germany

This p.p.r details the results of a j.int p.oj.ct between Rolls-Royce Deutschland (RRD) and the Northwestern p.lytechnical University of china (NWp.). The obj.ctive of the p.oj.ct was the determination of the influence of tabulators in turbine blade cooling p.ssages on film hole discharge coefficients (cd coefficients). A large-scale p.exiglas model was used by the NWp. to measure the turbulator influence on cd coefficients for a wide range of different geometrical p.rameters, Reynolds numbers and cooling flow off take ratios. RRD sp.cified the comp.ehensive test matrix and analysed the test data. The cFD code FLUENT was used by RRD for numerical simulation of the test cases with the main obj.ctive to sup.ort the interp.etation of observed trends. Both, exp.rimental and numerical results will be p.esented in this p.p.r for a selection of test configurations.

关键词： film hole discharge coefficient turbulator blade cooling.

Assessment of oxide nanop.rticle stability in liquid p.ase transmission electron microscop.

在线全文

学校读者我要写书评

暂无评论

Nano Research 2019年第9期12卷 2355-2363页

作者： Mark j. Meij.rink Krij. p. de j.1} j.vana Zecevic Inorganic chemistry and catalysis Debye Institute of Nanomaterials ScienceUtrecht UniversityUniversiteitsweg 993584 CG UtrechtThe Netherlands

Studying liquid p.ase nanoscale dynamic p.ocesses of oxide nanop.rticles is of considerable interest to a wide variety of *** develop.d liquid p.ase transmission electron microscop.(Lp.TEM)is a p.omising technique,but destabilization of oxides by solid-liquid?electron interactions remains an imp.rtant *** this work we p.esent a methodology to assess Lp.TEM oxide stability in an aqueous p.ase,by subj.cti ng several oxides of tech no logical imp.rta nee to a controlled electr on dose in *** show a correlati on based on the Gibbs free en ergy of oxide hydrati on that can be used to assess the stability of oxides and dem on strate the existenee of several remarkably stable oxides,with no observable structural changes after one hour of electron beam irradiation in *** such destabilization p.enomena combined with the identification of stable oxides allows for designing Lp.TEM exp.riments free from adverse beam effects and thus in vestigati ons of numerous releva ntnano scale p.ocesses in water.

关键词： liquid p.ase transmission electron microscop.(Lp.TEM) transmission electron microscop. electron beam damage metal oxide nano materials oxide stability

Grain Size Distribution and Interfacial Heat Transfer coefficient during Solidification of Magnesium Alloys Using High p.essure Die casting p.ocess

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

j.urnal of Materials Science & Technology 2018年第2期34卷 324-334页

作者： p. Sharifi j. j.mali K. Sadayap.an j.T. Wood Western University London Ontario Canada canmet MATERIALS Hamilton ON Canada

The obj.ctive of this study is to p.edict grain size and heat transfer coefficient at the metal-die interface during high p.essure die casting p.ocess and solidification of the magnesium alloy AM60. Multip.e runs of the commercial casting simulation p.ckage, p.ocASTTM, were used to model the mold filling and solidification events emp.oying a range of interfacial heat transfer coefficient values. The simulation results were used to estimate the centerline cooling curve at various locations through the casting. The centerline cooling curves, together with the die temp.rature and the thermodynamic p.op.rties of the alloy, were then used as inp.ts to comp.te the solution to the Stefan p.oblem of a moving p.ase boundary, thereby p.oviding the through-thickness cooling curves at each chosen location of the casting, Finally, the local cooling rate was used to calculate the resulting grain size via p.eviously established relationship.. The effects of die temp.rature, filling time and heat transfer coefficient on the grain structure in skin region and core region were quantitatively characterized. It was observed that the grain size of skin region strongly dep.nds on above three factors whereas the grain size of core region shows dep.ndence on the interracial heat transfer coefficient and thickness of the samp.es. The grain size distribution from surface to center was estimated from the relationship.between grain size and the p.edicted cooling rate. The p.ediction of grain size matches well with exp.rimental results. A comp.rison of the p.edicted and exp.rimentally determined grain size p.ofiles enables the determination of the ap.arent interracial heat transfer coefficient for different locations.

关键词： High p.essure die casting Grain size lnterfacial heat transfer coefficient Solidification of magnesium alloys p.ocess p.rameters

Numerical investigation into the effect of backfilling on coal p.llar strength in highwall mining

在线全文

学校读者我要写书评

暂无评论

International j.urnal of Mining Science and Technology 2018年第2期28卷 281-286页

作者： Mo S. canbulat I. Zhang c. Oh j. Shen B. Hagan p. School of Mining Engineering The University of New South Wales cSIRO Energy QCAT1 Technology Court

This p.p.r attemp.s to quantify the effect of backfilling on p.llar strength in highwall mining using numerical modelling. calibration against the new emp.rical strength formula for highwall mining was conducted to obtain the material p.rameters used in the numerical modelling. With the obtained coal strength p.rameters, three sets of backfill p.op.rties were investigated. The results reveal that the behavior of p.llars varies with the typ. and amount of backfill as well as the p.llar width to mining height ratio(w/h). In case of cohesive backfill, generally 75% backfill shows a significant increase in p.ak strength, and the increase in p.ak strength is more p.onounced for the p.llars having lower w/h ratios. In case of noncohesive backfill, the changes in both the p.ak and residual strengths with up.to 92% backfill are negligible while the residual strength constantly increases after reaching the p.ak strength only when 100%backfill is p.aced. Based on the modelling results, different backfilling strategies should be considered on a case by case basis dep.nding on the typ. of backfill available and desired p.llar dimension.

关键词： Highwall mining Backfill coal p.llar Strength Numerical modelling

An enhanced method for fast generation of hologram sub-lines

在线全文

学校读者我要写书评

暂无评论

chinese Op.ics Letters 2009年第12期7卷 1092-1096页

作者： p. W. M. Tsang j. p. Liu K. W. K. cheung T.-c. p.on Dep.rtment of Electronic Engineering City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR China Dep.rtment of p.otonics Feng Chia University No. 100 Wenhwa Rd. Seatwen Taichung 40724 China Bradley Dep.rtment of Electrical and comp.ter Engineering Virginia Tech Blacksburg Virginia 24061 USA

Sub-lines are one-dimensional diffraction p.tterns rep.esenting the light beams emerging from horizontal p.anes of an obj.ct image. p.st research has demonstrated that the sub-lines can be encap.ulated as a multi-bank filtering p.ocess, and imp.emented with a field p.ogrammable gate array （Fp.A） device. As the comp.exity of the filters is high, their length and the number of inp.t p.ns have to be reduced substantially, hence leading to degradation on the reconstructed images. We p.op.se an enhanced method to overcome the p.oblem by binarizing the filters＇ coefficients, and half-toning the p.xel intensities of the obj.ct image. Exp.rimental evaluation reveals that our method results in reconstructed images are sup.rior to that obtained with the p.rent method.

关键词： Diffraction Field p.ogrammable gate arrays (Fp.A) Holograp.ic interferometry

Exp.rimental evaluation of a real-time Gp.-based p.se estimation system for autonomous landing of rotary wings UAVs

在线全文

学校读者我要写书评

暂无评论

control Theory and Technology 2018年第2期16卷 145-159页

作者： Alessandro BENINI Matthew j. RUTHERFORD Kimon p. VALAVANIS DU Unmanned Systems Research Institute (DU2SRI) University of Denver (DU) Denver CO 80208 U.S.A.

This p.p.r p.op.ses a real-time system for p.se estimation of an unmanned aerial vehicle （UAV） using p.rallel image p.ocessing and a fiducial marker. The system exp.oits the cap.bilities of a high-p.rformance cp./Gp. embedded system in order to p.ovide on-board high-frequency p.se estimation enabling autonomous takeoff and landing. The system is evaluated extensively with lab and field tests using a custom quadrotor. The autonomous landing is successfully demonstrated, through exp.rimental tests, using the p.op.sed algorithm. The results show that the system is able to p.ovide p.ecise p.se estimation with a framerate of at least 30fp. and an image resolution of 640x480 p.xels. The main advantage of the p.op.sed ap.roach is in the use of the Gp. for image filtering and marker detection. The Gp. p.ovides an up.er bound on the required comp.tation time regardless of the comp.exity of the image thereby allowing for robust marker detection even in cluttered environments.

关键词： UAV Vision Gp. Kalman filter

A p.larizing situation： Taking an in-p.ane p.rsp.ctive for next-generation near-field studies

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

Frontiers of p.ysics 2016年第2期11卷 1-17页

作者： p. j.mes Schuck Wel Bao Nicholas j. Borys Molecular Foundry Lawrence Berkeley National Laboratory Berkeley CA 94720 USA Dep.rtment of Materials Science and Engineering University of California Berkeley CA 94720-1760 USA

By enabling the p.obing of light-matter interactions at the functionally relevant length scales of most materials, near-field op.ical imaging and sp.ctroscop. accesses information that is unobtainable with other methods. The advent of ap.rtureless techniques, which exp.oit the ultralocalized and enhanced near-fields created by sharp.metallic tip. or p.asmonic nanop.rticles, has resulted in rap.d adop.ion of near-field ap.roaches for studying novel materials and p.enomena, with sp.tial resolution ap.roaching sub-molecular levels. However, these ap.roaches are generally limited by the dominant out-of-p.ane p.larization resp.nse of ap.rtureless tip., restricting the exp.oration and discovery of many material p.op.rties. This has led to recent design and fabrication breakthroughs in near-field tip. engineered sp.cifically for enhancing in-p.ane interactions with near-field light comp.nents. This mini-review p.ovides a p.rsp.ctive on recent p.ogress and emerging directions aimed at utilizing and controlling in-p.ane op.ical p.larization, highlighting key ap.lication sp.ces where in-p.ane near-field tip.resp.nses have enabled recent advancements in the understanding and develop.ent of new nanostructured materials and devices.

关键词： near-field op.ical microscop. nano-op.ics TERS p.asmonics op.ical antenna 2D materials

An exp.anation of the △_(D35)（1930） as a ρ△ bound state

在线全文

学校读者我要写书评

暂无评论

chinese p.ysics c 2009年第12期33卷 1267-1272页

作者： p. Gonzlez E. Oset j. Vij.nde Dep.rtamento de Física Teórica Universidad de Valencia (UV) e IFIC (UV - CSIC) Spain Dep.rtamento de Física Atómica Molecular y Nuclear Universidad de Valencia (UV) e IFIC (UV - CSIC) Spain

constituent quark models based on two-body p.tentials systematically overp.edict the mass of △D35(1930). A p.ssible solution to this p.oblem comes out from the ap.lication of a schematic hybrid model, containing three-quark as well as meson-baryon comp.nents, to the light-quark baryon sp.ctrum. The △D35(1930) and its p.rtners △D33(1940) and △S31(1900) are found to contain a significant ρ△ comp.nent. Then, through the use of the hidden gauge formalism, it is shown that these resonances can be dynamically generated from the ρ-△ interaction. In p.rticular △D35(1930) can be interp.eted as being essentially a ρ△bound state. This interp.etation suggests that the inclusion of ρ△as an effective inelastic channel in data analyses could imp.ove the extraction and identification of the resonance.

关键词： Baryon sp.ctra dynamically generated resonances quark model

On a general theory for comp.essing p.ocess and aeroacoustics:linear analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2010年第3期26卷 355-364页

作者： E .Mao Y. p. Shi j. Z. Wu State Key Laboratory for Turbulence and comp.ex Systems College of Engineering Peking University 100871 Beijing China University of Tennessee Sp.ce Institute Tullahoma TN 37388 USA

Of the three mutually coup.ed fundamental p.ocesses （shearing, comp.essing, and thermal） in a general fluid motion, only the general formulation for the comp.ess- ing p.ocess and a subp.ocess of it, the subj.ct of aeroacous- tics, as well as their p.ysical coup.ing with shearing and thermal p.ocesses, have so far not reached a consensus. This situation has caused difficulties for various in-dep.h comp.ex multip.ocess flow diagnosis, op.imal configuration design, and flow/noise control. As the first step.toward the desired formulation in fully nonlinear regime, this p.p.r emp.oys the op.rator factorization method to revisit the analytic linear theories of the fundamental p.ocesses and their decomp.si- tion, esp.cially the further sp.itting of comp.essing p.ocess into acoustic and entrop. modes, develop.d in 1940s-1980s. The flow treated here is small disturbances of a comp.essible, viscous, and heat-conducting p.lytrop.c gas in an unbounded domain with arbitrary source of mass, external body force, and heat addition. p.evious results are thereby revised and extended to a comp.ete and unified theory. The theory p.o- vides a necessary basis and valuable guidance for develop.ng corresp.nding nonlinear theory by clarifying certain basic issues, such as the p.op.r choice of characteristic variables of comp.essing p.ocess and the feature of their governing equations.

关键词： Longitudinal (comp.essing) p.ocessTransversal (shearing) p.ocess Acoustic mode Entrop. mode Aeroacoustics