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931.
This paper studies a problem of scheduling fabrication and assembly operations in a two-machine flowshop, subject to the same predetermined job sequence on each machine. In the manufacturing setting, there are n products, each of which consists of two components: a common component and a unique component which are fabricated on machine 1 and then assembled on machine 2. Common components of all products are processed in batches preceded by a constant setup time. The manufacturing process related to each single product is called a job. We address four regular performance measures: the total job completion time, the maximum job lateness, the total job tardiness, and the number of tardy jobs. Several optimality properties are presented. Based upon the concept of critical path and block schedule, a generic dynamic programming algorithm is developed to find an optimal schedule in O(n 7) time. 相似文献
932.
Sae‐Jin Kim Joohwi Lee Seung‐Cheol Lee Chan Park Cheol Seong Hwang Jung‐Hae Choi 《固体物理学:研究快报》2012,6(3):108-110
The migration barrier energies of the nitrogen atom and N2 molecule, and the activation barriers for the dissociation and formation of N2 in Ge2Sb2Te5 were calculated by ab‐initio methods. Various transition and metastable states were found along the migration pathway. Migration barrier energies up to 1.19 eV for the nitrogen atom suggest that it is difficult for it to move from one site to any other site or diffuse out from Ge2Sb2Te5 although doped nitrogen is energetically less stable with respect to N2 in vacuum. N2 in Ge2Sb2Te5 was hardly expected to dissociate into nitrogen atoms and vice versa. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
933.
934.
935.
J. H. Hamilton A. V. Ramayya J. K. Hwang G. M. Ter-Akopian A. V. Daniel T. N. Ginter C. J. Beyer J. Kormicki X. Q. Zhang A. M. Rodin A. S. Fomichev J. Kliman L. Krupa J. Jandel Yu. Ts. Oganessian W. Greiner D. N. Poenaru G. Chubaryan D. Seweryniak R. V. F. Janssens J. O. Rasmussen S. C. Wu R. Donangelo W. C. Ma R. B. Piercey J. D. Cole 《Acta Physica Hungarica A》2001,14(1-4):161-168
The spontaneous fission of 252Cf has been studied via γ-γ-γ coincidence and γ-γ light charged particle coincidence with Gammasphere. The binary fission yields of correlated Mo?Ba pairs with 0–10 neutron emission have been remeasured. The existence of “hot” fission mode with 8–10 neutron emission seen previously in the Mo?Ba split is confirmed but with lower intensities. By gating on the light charged particles detected in ΔE-E detectors and a γ ray in one partner, the relative yields of correlated pairs in alpha ternary SF with zero to 6n emission are observed for the first time with the distribution peaked at 2.5n. New correlated pairs are identified in 10Be ternary SF. We observed essentially only cold, On 10Be and little, if any, hot, xn 10Be. New γ-γ-γ data with 2.3 times the total events show weak non-Doppler broadened high energy peaks in coincidence with transitions in correlated pairs in 10Be SF shifted by the same 6,1 to 26 keV from the 2-0 energy in 10Be as seen earlier. 相似文献
936.
Headspace solid phase microextraction (HS-SPME) in-situ supercritical fluid extraction (SFE) was investigated for the determination of trace amounts of perfluorocarboxylic acids (PFCAs) in sediments. Quantitation was performed by using gas chromatography coupled to negative chemical ionization-tandem mass spectrometry (GC-NCI-MS/MS). The optimum conditions of HS-SPME following SFE were obtained using 500 μL n-butanol as a derivatization reagent in supercritical carbon dioxide with static extraction for 10 min, then dynamic extraction for 20 min at 30 MPa and 70 °C and simultaneous collected with 100 μm film thickness PDMS fiber. The linear range of proposed method was from 5 to 5000 ng g(-1), with limit of detection ranging from 0.39 to 0.54 ng g(-1) and limit of quantitation ranging from 1.30 to 1.80 ng g(-1). The developed method was successfully applied to analyze PFCAs in sediments from rivers and beach near industrial areas. The concentrations of PFCAs determined are from 282 to 4473 ng g(-1). 相似文献
937.
Inseon Kim Seunghun S. Lee Seung Hyun L. Kim Sunghoon Bae Hoyon Lee Nathaniel S. Hwang 《Macromolecular bioscience》2019,19(5)
Bone is a vascularized tissue that is comprised of collagen fibers and calcium phosphate crystals such as hydroxyapatite (HAp) and whitlockite (WH). HAp and WH are known to elicit bone regeneration by stimulating osteoblast activities and osteogenic commitment of stem cells. In addition, vascular endothelial growth factor (VEGF) is shown to promote osteogenesis and angiogenesis which is considered as an essential process in bone repair by providing nutrients. In this study, VEGF‐secreting human adipose‐derived stem cells (VEGF‐ADSCs) are developed by transducing ADSCs with VEGF‐encoded lentivirus. Additionally, WH‐reinforced gelatin/heparin cryogels (WH‐C) are fabricated by loading WH into gelatin/heparin cryogels. VEGF‐ADSC secrete tenfold more VEGF than ADSC and show increased VEGF secretion with cell growth. Also, incorporation of WH into cryogels provides a mineralized environment with ions secreted from WH. When the VEGF‐ADSCs are seeded on WH‐C, sustained release of VEGF is observed due to the specific affinity of VEGF to heparin. Finally, the synergistic effect of VEGF‐ADSC and WH on osteogenesis is successfully confirmed by alkaline phosphatase and real‐time polymerase chain reaction analysis. In vivo bone formation is demonstrated via implantation of VEGF‐ADSC seeded WH‐C into mouse calvarial bone defect model, resulted in enhanced bone development with the highest bone volume/total volume. 相似文献
938.
Mohandas Annapoorna Sun Wook Nimal T. R. Shankarappa Sahadev A. Hwang Nathaniel S. Jayakumar Rangasamy 《Research on Chemical Intermediates》2018,44(8):4873-4887
Research on Chemical Intermediates - The work focuses on the development of an injectable chitosan-fibrin (CF) based nanocomposite hydrogel for angiogenic response. The hydrogel base is made of... 相似文献
939.
Park Young Jin Lee K. B. Lee J. M. Park T. S. Hwang S. H. 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(3):1195-1203
Journal of Radioanalytical and Nuclear Chemistry - We have studied to validate the calorimetric method by comparing the 123I radioactivity measurement results with the national standard. The reason... 相似文献
940.
A unified energy approach to a class of micromechanics models for composite materials 总被引:4,自引:0,他引:4
Several micromechanics models for the determination of composite moduli are investigated in this paper, including the dilute
solution, self-consistent method, generalized self-consistent method, and Mori-Tanaka's method. These micromechanical models
have been developed by following quite different approaches and physical interpretations. It is shown that all the micromechanics
models share a common ground, the generalized Budiansky's energy-equivalence framework. The difference among the various models
is shown to be the way in which the average strain of the inclusion phase is evaluated. As a bonus of this theoretical development,
the asymmetry suffered in Mori-Tanaka's method can be circumvented and the applicability of the generalized self-consistent
method can be extended to materials containing microcracks, multiphase inclusions, non-spherical inclusions, or non-cylindrical
inclusions. The relevance to the differential method, double-inclusion model, and Hashin-Shtrikman bounds is also discussed.
The application of these micromechanics models to particulate-reinforced composites and microcracked solids is reviewed and
some new results are presented. 相似文献