检索结果-南通市图书馆

Effects of Alumina on Cristobalite Crystallization and Properties of Silica-Based Ceramic Cores

The First China-j.pan-k.rea j.int Symposium on Optimization of Structural and Mechanical Systems

作者： j. H. choi B. Y. Lee Department of Aeronaut and Mech. Engrg. Hankuk Aviation University Koyang-shi Kyunggi-do Korea Dept.of Automotive Engineering Keimyung UniversityTaeguKorea

＜正＞A Boundary integral method is applied in finding optimum shape of endosseous implant in dentistry, where the stress value is of great importance for successful osseointegration at the implant-bone interface. Obj.ctive is to design the implant so as to avoid bone resorpiion, which leads to serious failure. A von Mises stress functional at the zonal interface is considered to this end. Sensitivities in terms of the interface shape of the implant body are computed based on the formula by the boundary integral method. The problem is assumed axisymmetric having 3 zones of implant, cortical and cancellous bone. New optimum designs are obtained using sequential linear programming method for several cases such as different fixed conditions, different obj.ctives and different design variables. As a result, the optimum shape is found heavily dependent on the surrounding conditions, which means more precise modeling should be provided for more reliable implant solution. Interestingly the optimum shapes look.similar to those of tooth root which is the natural optimum. The method can be a useful tool for the practical implant design as long as its own features such as threaded shape are accounted for.

关键词： Boundary Element Method Shape Design Sensitivity Analysis Optimum Shape Design Interface Problem Endosseous Implant

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

j.urnal of Materials Science & Technology 2017年第2期33卷 204-209页

作者： j.j.Liang Q.H.Lin X.Zhang T.j.n Y.Z.Zhou X.F.Sun B.G.choi I.S.k.m j.H.Do C.Y.j. Institute of Metal Research Chinese Academy of SciencesShenyang 110016China k.rea Institute of Materials Science Changwon 642-831Republic of Korea

In this work. the influences of alumina addition on cristobalite crystallization and properties of inj.c- tion molded silica-based ceramic cores were investigated. X-ray diffraction （XRD） was used to characterize phase transformations in the samples, and the XRD result indicated that the addition of alumina pro- moted crystallization of fused silica during sintering at 1180-1220 ℃ and thus increases the amount of cristobalite. The increased amount of cristobalite as well as alumina addition led to much more thermal dilation due to their higher coefficients of thermal expansion than that of fused silica. The flexural strengths at room temperature and 1500 ~C were tested, and it was shown that alumina addition could not affect room temperature strength, but decreased the flexural strength at 1500 ℃. In addition, deflection resis- tance during heating to high temperatures was investigated, and the result indicated that alumina addition speeded up high temperature softening of the samples. XRD and scanning electron microscopy equipped with energy dispersive spectrometry （SEMj.DS） analysis suggested that this softening behavior was related with viscous flow sintering which could be accelerated by the reaction of alumina and silica with a product of mullite.

关键词： Silica-based ceramic cores Alumina Cristobalite crystallization Properties

Crystal Facet Engineering of TiO_(2) Nanostructures for Enhancing Photoelectrochemical Water Splitting with BiVO_(4) Nanodots

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2022年第3期14卷 201-215页

作者： Mi Gyoung Lee j.n Wook.Yang Hoonk.e Park.Cheon Woo Moon Dinsefa M.Andoshe j.ngseong Park.Chang‑k. Moon Tae Hyung Lee k.oung Soon choi Woo Seok.Cheon j.ng‑j.o k.m Ho Won j.ng Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoul 08826Republic of Korea Department of Chemistry and Nanoscience Ewha Womans UniversitySeoul 03693Republic of Korea National Research Facilities and Equipment Center Korea Basic Science InstituteDaejeon 34133Republic of Korea Advanced Institute of Convergence Technology Seoul National UniversitySuwon 16229Republic of Korea

Although bismuth vanadate(BiVO4)has been promising as photoanode material for photoelectrochemical water splitting,its charge recombination issue by short charge diffusion length has led to various studies about heterostructure *** a hole block.ng layer of BiVO4,titanium dioxide(TiO_(2)) has been considered unsuitable because of its relatively positive valence band edge and low electrical ***,a crystal facet engineering of TiO_(2) nanostructures is proposed to control band structures for the hole block.ng layer of BiVO4 *** design two types of TiO_(2) nanostructures,which are nanorods(NRs)and nanoflowers(NFs)with different(001)and(110)crystal facets,respectively,and fabricate BiVO4/TiO_(2) heterostructure *** BiVO4/TiO_(2) NFs showed 4.8 times higher photocurrent density than the BiVO4/TiO_(2) *** decay time analysis and time-resolved photoluminescence reveal the enhancement is attributed to the reduced charge recombination,which is originated from the formation of type II band alignment between BiVO4 nanodots and TiO_(2) *** work.provides not only new insights into the interplay between crystal facets and band structures but also important steps for the design of highly efficient photoelectrodes.

关键词： Crystal facet control Bismuth vanadate Titanium dioxide Heteroj.nction Water splitting

Portable System for CWA Detection Using Micro Array Gas Sensor

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2006年第A3期35卷 124-128页

作者： j.H.k.ak.Y.T.Lim G.H.k.m N.j.choi H.D.Park.G.H.Rue j.S.Huh j.C.k.m D.D.Lee School of Electrical Engineering and Computer Science Kyungpook National UniversityDaegu 1370Korea Electronics and Telecommunications Research Institute Future Technology Research Division New Functional Information Devices TeamGajeongYuseong-GuDaejeon 161 Korea k.rea Electronics Technology Institute Yatap-DongBundang-GuSeongnam-SiGyeonggi-Do #68Korea Department of Materials Science and Metallurgy Kyungpook National UniversityDaegu 1370Korea Department of Chemical Engineering Kyungpook National UniversityDaegu 1370Korea

Biochemistry weapon is raising new tools of war and *** research is an experiment about portable system for CWAs (chemical warfare agents) detection using micro array gas *** were divided into four types such as blood, nerve,vesicant,and chok.ng *** detect various CWAs,semiconductor thick.film sensor array based on tin oxide was fabricated and their gas responses were *** temperature was range of 250℃to 350℃and gas concentration was range of 0.1μg/g to 10μg/*** array was measured as operating temperatures,concentrations for four simulant agents of *** parameters from results were carried out classification among CWAs through the principal component analysis (PCA).Also,classification of gases is studied using adaptive resonance theory (ART) that is one of neural network.*** displayed using PDA system.

关键词： SnO2 chemical warfare agents(CWAs) portable system ART array PCA

Two-Phase Image Inpainting: Combine Edge-Fitting with PDE Inpainting

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2012年第6期4卷 769-779页

作者： Meiqing Wang Chensi Huang Chao Zeng choi-Hong Lai College of Mathematics and Computer Science Fuzhou UniversityFuzhou 350002FujianChina School of Computing and Mathematical Sciences University of GreenwichOld Royal Naval CollegePark RowGreenwichLondon SE109LSUK

The digital image inpainting technology based on partial differential equations(PDEs)has become an intensive research topic over the last few years due to the mature theory and prolific numerical algorithms of ***,PDE based models are not effective when used to inpaint large missing areas of images,such as that produced by obj.ct *** overcome this problem,in this paper,a two-phase image inpainting method is ***,some edges which cross the damaged regions are located and the missing parts of these edges are fitted by using the cubic spline *** fitted edges partition the damaged regions into some smaller damaged *** these smaller regions may be inpainted by using classical PDE *** results show that the inpainting results by using the proposed method are better than those of BSCB model and TV model.

关键词： Image inpainting partial differential equations edge fitting

Bioactive hydrogel microcapsules for guiding stem cell fate decisions by release and reloading of growth factors

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

Bioactive Materials 2022年第9期7卷 1-14页

作者： k.hak.Gwon Hye j.n Hong Alan M.Gonzalez-Suarez Michael Q.Slama Daheui choi j.nk.e Hong Harihara Bask.ran Gulnaz Stybayeva Quinn P.Peterson Alexander Revzin Department of Physiology and Biomedical Engineering Mayo ClinicRochesterMN55902USA Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoul03722Republic of Korea Department of Chemical and Biomolecular Engineering Case Western Reserve UniversityClevelandOH44106USA

Human pluripotent stem cells(hPSC)hold considerable promise as a source of adult cells for treatment of diseases ranging from diabetes to liver *** of the challenges that limit the clinical/translational impact of hPSCs are high cost and difficulty in scaling-up of existing differentiation *** this paper,we sought to address these challenges through the development of bioactive microcapsules.A co-axial flow focusing microfluidic device was used to encapsulate hPSCs in microcapsules comprised of an aqueous core and a hydrogel ***,the shell contained heparin moieties for growth factor(GF)binding and *** aqueous core enabled rapid aggregation of hPSCs into 3D spheroids while the bioactive hydrogel shell was used to load inductive cues driving pluripotency maintenance and endodermal ***,we demonstrated that one-time,1 h long loading of pluripotency signals,fibroblast growth factor(FGF)-2 and transforming growth factor(TGF)-β1,into bioactive microcapsules was sufficient to induce and maintain pluripotency of hPSCs over the course of 5 days at levels similar to or better than a standard protocol with soluble ***,stem cell-carrying microcapsules that previously contained pluripotency signals could be reloaded with an endodermal cue,Nodal,resulting in higher levels of endodermal mark.rs compared to stem cells differentiated in a standard ***,bioactive heparin-containing core-shell microcapsules decreased GF usage five-fold while improving stem cell phenotype and are well suited for 3D cultivation of hPSCs.

关键词： Droplet microfluidics Bioactive core-shell microcapsule Growth factor release 3D stem cell culture Stem cell differentiation

In Situ Experiments for the Validation of Disposal System at k.ERI Underground Research Tunnel

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

In Situ Experiments for the Validation of Disposal System at...

Intimate atomic Cu-Ag interfaces for high CO2RR selectivity towards CH4 at low over potential

第十二次全国岩石力学与工程学术大会

作者： choi Sangk. k.on H.j.choi j.W.choi Department of Energy Resources Engineering Inha University k.rea Atomic Energy Research Institute

In k.rea,21 nuclear power plants are operating and more than 11,000 tons of spent fuels, which are now stored at interim storage at the reactor sites,had been *** many other countries operating nuclear power plants,the safe and reliable management of spent fuel is an urgent national issue for the sustainable utilization of nuclear *** considers deep geological disposal as a most promising ways for the disposal of spent fuel or high-level *** a long term research and development started in 1997,k.rea Atomic Energy

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Nano Research 2021年第10期14卷 3497-3501页

作者： Chungseok.choi j.n Cai Changsoo Lee Hyuck.Mo Lee Mingj.e Xu Yu Huang Department of Materials Science and Engineering University of CaliforniaLos AngelesCA 90095USA Hydrogen Energy Department Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology291 Daehak-roYuseong-guDaejeon 34141Republic of Korea Irvine Materials Research Institute(IMRI) University of CaliforniaIrvineCA 92697USA Department of Materials Science and Engineering University of CaliforniaIrvineCA 92697USA

Developing highly efficient electrochemical catalysts for carbon dioxide reduction reaction(CO_(2)RR)provides a solution to battle global warming issues resulting from ever-increasing carbon footprint due to human ***(Cu)is k.own for its efficiency in CO_(2)RR towards value-added hydrocarbons;hence its unique structural properties along with various Cu alloys have been extensively explored in the past ***,we demonstrate a two-step approach to achieve intimate atomic Cu-Ag interfaces on the surface of Cu nanowires,which show greatly improved CO_(2)RR selectivity towards methane(CH4).The specially designed Cu-Ag interfaces showed an impressive maximum Faradaic efficiency(FE)of 72%towards CH4 production at-1.17 V(*** hydrogen electrode(RHE)).

关键词： electrochemical CO_(2)reduction reaction catalyst copper silver bimetallic interface

Coastal wetlands in Lianyungang,j.angsu Province,China:probably the most important site globally for the Asian Dowitcher(Limnodromus semipalmatus)

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

Avian Research 2021年第3期12卷 364-374页

作者： Ziyou Yang j.ng Li Yongxiang Han Chris j.Hassell k.r-Sin k.therine Leung David S.Melville Yat-tung Yu Lin Zhang Chi-Yeung choi Spoon-Billed Sandpiper(Shanghai)Environmental Protection Technology Co. Ltd.Shanghai 201100China Lianyungang Xugou Primary School Lian-yungang 222042China Global Flyway Network PO Box 3089BroomeWA 6725Australia Hong k.ng Waterbirds Ringing Group Mai Po Nature ReserveHong KongChina 1261 Dovedale Road RD 2 WakefieldNelson 7096New Zealand Hong k.ng Bird Watching Society 7CV Ga Building532 Castle Peak RoadLai Chi KokKowloonHong KongChina School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

Back.round:Despite an increasing number of surveys and a growing interest in birdwatching,the population and distribution of Asian Dowitcher(Limnodromus semipalmatus),a species endemic to the East Asian-Australasian and Central Asian Flyways,remains poorly understood,and published information about the species is largely *** boreal spring 2019,over 22,432 Asian Dowitchers were recorded in a coastal wetland at Lianyungang,j.angsu Prov-ince,China,constituting 97.5%of its estimated global ***:In 2019 and 2020,we conducted field surveys at Lianyungang to determine the numbers of Asian Dow-itchers using the area during both southward and northward *** also assessed the distribution and abun-dance of Asian Dowitchers elsewhere along the China coast by searching literature and consulting expert ***:The coastal wetlands of Lianyungang are the most important stopover site for Asian Dowitchers during both northward and southward migrations;they supported over 90%of the estimated global population during north-ward migration in two consecutive years(May 2019 and 2020).This area also supported at least 15.83%and 28.42%(or 30.74%and 53.51%using modelled estimates)of the global population during southward migration in 2019 and 2020 *** wetlands in the west and north of Bohai Bay also have been important stopover sites for the species since the *** comprehensive,long-term monitoring data are lack.ng,available evidence sug-gests that the population of the species may have ***:The high concentration of Asian Dowitchers at Lianyungang during migration means the species is highly susceptible to human disturbances and natural stochastic *** coastal wetlands of Lianyungang should be protected and potentially qualify for inclusion in China’s forthcoming nomination for World Heritage listing of Migratory Bird Sanctuaries along the Coast of Yellow Sea-Bohai Gulf of China(Phase II)in ***

关键词： Lianyungang Limnodromus semipalmatus Shorebird Stopover ecology Yellow Sea World Heritage