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排序方式: 共有358条查询结果,搜索用时 125 毫秒
291.
James M.TIEN Ananth KRISHNAMURTHY Ali YASAR Department of Decision Sciences Engineering Systems Rensselaer Polytechnic Institute Eighth St.Troy New York USA 《系统科学与系统工程学报(英文版)》2004,13(3):257-278
Our focus herein is on developing an effective taxonomy for the simultaneous and real-timemanagement of supply and demand chains.More specifically,the taxonomy is developed in terms ofits underpinning components and its research foci.From a components perspective,we first considerthe value chain of supplier,manufacturer,assembler,retailer,and customer,and then develop aconsistent set of definitions for supply and demand chains based on the location of the customer orderpenetration point.From a research perspective,we classify the methods that are employed in themanagement of these chains,based on whether supply and/or demand are flexible or fixed.Interestingly,our taxonomy highlights a very critical research area at which both supply and demandare flexible,thus manageable.Simultaneous management of supply and demand chains sets the stagefor mass customization which is concerned with meeting the needs of an individualized customermarket.Simultaneous and real-time management of supply and demand chains set 相似文献
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Fused deposition modelling (FDM) is a filament based rapid prototyping system which offers the possibility of introducing new composite material for the FDM process as long as the new material can be made in feedstock filament form. Swinburne has been undertaking extensive research in development of new composite materials involving acrylonitrile-butadiene-styrene (ABS) and other materials including metals. In order to predict the behaviour of new ABS based composite materials in the course of FDM process, it is necessary to investigate the flow of the composite material in liquefier head. No such study is available considering the geometry of the liquefier head. This paper presents 2-D and 3-D numerical analysis of melt flow behaviour of a representative ABS-iron composite through the 90-degree bent tube of the liquefier head of the fused deposition modelling process using ANSYS FLOTRAN and CFX finite element packages. Main flow parameters including temperature, velocity, and pressure drop have been investigated. Filaments of the filled ABS have been fabricated and characterized to verify the possibility of prototyping using the new material on the current FDM machine. Results provide promising information in developing the melt flow modelling of metal-plastic composites and in optimising the FDM parameters for better part quality with such composites. 相似文献
295.
Effects of different friction stir welding conditions on the microstructure and mechanical properties of copper plates
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Friction stir welding is a new and innovative welding method used to fuse materials. In this welding method, the heat generated by friction and plastic flow causes significant changes in the microstructure of the material, which leads to local changes in the mechanical properties of the weld. In this study, the effects of various welding parameters such as the rotational and traverse speeds of the tool on the microstructural and mechanical properties of copper plates were investigated; additionally, Charpy tests were performed on copper plates for the first time. Also, the effect of the number of welding passes on the aforementioned properties has not been investigated in previous studies. The results indicated that better welds with superior properties are produced when less heat is transferred to the workpiece during the welding process. It was also found that although the properties of the stir zone improved with an increasing number of weld passes, the properties of its weakest zone, the heat-affected zone, deteriorated. 相似文献
296.
S. Karamat C. Ke U.Y. Inkay Rizwan Akram Ilker Yildiz S. Shah Zaman A. Oral 《自然科学进展(英文版)》2016,26(4):422-426
The present paper focuses on study of graphene and strontium titanate(SrTiO_3 or STO) interface. An ambient pressure chemical vapour deposition(AP-CVD) setup is used to grow graphene on STO(110)substrates in the presence of methane, argon and hydrogen gases at 1000 °C for 4 h. Raman spectroscopy measurements confirm the presence of graphene on STO substrates due to the existence of typical D and G peaks referring to graphene. These characteristic peaks are missing in the spectrum for bare substrates.X-ray photoelectron spectroscopy(XPS) is carried out for elemental analysis of samples, and study their bonding with STO substrates. We employed the valence band spectrum to calculate the valence band offset(VBO) and conduction band offset(CBO) at the G-STO interface. Also, we present an energy band diagram for Bi-layer and ABC(arranging pattern of carbon layers) stacked graphene layers. 相似文献
297.
Shakil Khan Muhammad Shahi A. Mahmoo A. Shah Ishaq Ahme Mazhar Mehmoo U. Aziz Q. Raz M. Alam 《自然科学进展(英文版)》2015,25(4):282-290
DC reactive magnetron sputtering technique has been used for the preparation of Al N thin fi lms. The deposition temperature and the fl ow ratio of N2/Ar were varied and subsequent dependency of the fi lms crystallites orientation/texture has been addressed. In general, deposited fi lms were found hexagonal polycrystalline with a(002) preferred orientation. The X-ray diffraction(XRD) data revealed that the fi lm crystallinity improves,with the increase of substrate temperature from 300 ℃to 500℃. The dropped in full width half maximum(FWHM) of the XRD rocking curve value further con fi rmed it. However, increasing substrate temperature above 500 ℃or reducing the nitrogen condition(from 60 to 30% in the environment) induced the growth of crystallites with(102) and(103) orientations. The rise of rocking curve FWHM for the corresponding conditions depicted that the fi lms texture quality deteriorated. A further con fi rmation of the variation in fi lm texture/orentation with the growth conditions has been obtained from the variation in FWHM values of a dominant E1(TO) mode in the Fourier transform infrared(FTIR) spectra and the E2(high) mode in Raman spectra. We have correlated the columnar structure in AFM surface analyses with the(002) or c-axis orientation as well. Spectroscopic ellipsometry of the samples have shown a higher refractive index at 500 ℃growth temperature. 相似文献
298.
Tomlins SA Laxman B Dhanasekaran SM Helgeson BE Cao X Morris DS Menon A Jing X Cao Q Han B Yu J Wang L Montie JE Rubin MA Pienta KJ Roulston D Shah RB Varambally S Mehra R Chinnaiyan AM 《Nature》2007,448(7153):595-599
Recently, we identified recurrent gene fusions involving the 5' untranslated region of the androgen-regulated gene TMPRSS2 and the ETS (E26 transformation-specific) family genes ERG, ETV1 or ETV4 in most prostate cancers. Whereas TMPRSS2-ERG fusions are predominant, fewer TMPRSS2-ETV1 cases have been identified than expected on the basis of the frequency of high (outlier) expression of ETV1 (refs 3-13). Here we explore the mechanism of ETV1 outlier expression in human prostate tumours and prostate cancer cell lines. We identified previously unknown 5' fusion partners in prostate tumours with ETV1 outlier expression, including untranslated regions from a prostate-specific androgen-induced gene (SLC45A3) and an endogenous retroviral element (HERV-K_22q11.23), a prostate-specific androgen-repressed gene (C15orf21), and a strongly expressed housekeeping gene (HNRPA2B1). To study aberrant activation of ETV1, we identified two prostate cancer cell lines, LNCaP and MDA-PCa 2B, that had ETV1 outlier expression. Through distinct mechanisms, the entire ETV1 locus (7p21) is rearranged to a 1.5-megabase prostate-specific region at 14q13.3-14q21.1 in both LNCaP cells (cryptic insertion) and MDA-PCa 2B cells (balanced translocation). Because the common factor of these rearrangements is aberrant ETV1 overexpression, we recapitulated this event in vitro and in vivo, demonstrating that ETV1 overexpression in benign prostate cells and in the mouse prostate confers neoplastic phenotypes. Identification of distinct classes of ETS gene rearrangements demonstrates that dormant oncogenes can be activated in prostate cancer by juxtaposition to tissue-specific or ubiquitously active genomic loci. Subversion of active genomic regulatory elements may serve as a more generalized mechanism for carcinoma development. Furthermore, the identification of androgen-repressed and insensitive 5' fusion partners may have implications for the anti-androgen treatment of advanced prostate cancer. 相似文献
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Weir BA Woo MS Getz G Perner S Ding L Beroukhim R Lin WM Province MA Kraja A Johnson LA Shah K Sato M Thomas RK Barletta JA Borecki IB Broderick S Chang AC Chiang DY Chirieac LR Cho J Fujii Y Gazdar AF Giordano T Greulich H Hanna M Johnson BE Kris MG Lash A Lin L Lindeman N Mardis ER McPherson JD Minna JD Morgan MB Nadel M Orringer MB Osborne JR Ozenberger B Ramos AH Robinson J Roth JA Rusch V Sasaki H Shepherd F Sougnez C Spitz MR Tsao MS Twomey D Verhaak RG Weinstock GM Wheeler DA Winckler W 《Nature》2007,450(7171):893-898