检索结果-南通市图书馆

Magnetocaloric Effect in Anisotropic Mixed Spin1/2–1 System: Pair Approximation Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2019年第11期71卷 1370-1378页

作者： Abderrazak Boubekri Moulay Youssef el Hafidi mohamed el Hafidi Laboratory of Condensed Matter Physics Faculty of Sciences Ben M’sik Hassan II University of Casablanca

We use the Pair Approximation method to analyze the magnetic and magnetocaloric behaviors of diluted mixed spin SA=1 and spin SB=1/2 with the anisotropic Heisenberg model, on a cubic lattice with coordination number z=6. Our system is described in presence of an external magnetic field;the phase diagram and thermodynamic properties related to the concentration of magnetic atom(A or B) and the single ion anisotropy are constructed and *** attention is paid to magnetocaloric properties provided by isothermal entropy change as well as the cooling capacity. These cooling power keys are plotted and discussed as a function of interaction anisotropy and magnetic component concentration of two sublattices ions A and B. Numerical results show a double peak structure in the entropy change curve and the inverse magnetocaloric effect related to the presence of the negative single-ion anisotropy.

关键词： anisotropic Heisenberg model dilution entropy change mixed spin system inverse magnetocaloric effect pair approximation magnetic Gruneisen ratio

NANOPOROUS MATERIALS BASED ON SPIROKETAL AND SPIROTHIOKETAL POLYMERS FOR SEPARATING METHANOL-TOLUENE MIXTURE

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2011年第4期29卷 450-455页

作者： Hamada Hamada Abdel-Razik Zeinhom mohamed el-Bahy Chemistry Department Faculty of Science and Education(Alkhurma Branch)Taif UniversitySaudi Arabia

Organic microporous materials based on spiroketal and spirothioketal polymers were synthesized through 1,3- dioxol-forming polymerization reaction between pentaerythritol or pentaerythritol tetrathiol and different types of cyclohexa- 1,4-dione derivatives. The structure of the prepared polymers was confirmed by NMR spectroscopy and molecular mass measurements. Nitrogen adsorption/desorption isotherms of the prepared polymers show a large amount of nitrogen adsorbed at low relative pressure indicating microporosity. These polymers have Brunauer Emmitt and Teller （BET） surface areas in the range from 492 （m^2g^-1） to 685 （m^2 g^-1）. The prepared polymers were found to be useful for pervaporation separation of methanol-toluene mixture with a separation factor up to 12.5 and fluxes, varying between 6.7×10-3 kg/（m^2 h） and 13.4 × 10^-3 kg/（m^2 h）.

关键词： Spiroketal polymers Nanoporous materials Separation membranes.

A Taxonomy of Exact Methods for Partial Max-SAT

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2013年第2期28卷 232-246页

作者： mohamed el Bachir Menai Tasniem Nasser Al-Yahya Department of Computer Science College of Computer and Information Sciences King Saud University

Partial Maximum Boolean Satisfiability （Partial Max-SAT or PMSAT） is an optimization variant of Boolean satisfiability （SAT） problem, in which a variable assignment is required to satisfy all hard clauses and a maximum number of soft clauses in a Boolean formula. PMSAT is considered as an interesting encoding domain to many reaHife problems for which a solution is acceptable even if some constraints are violated. Amongst the problems that can be formulated as such are planning and scheduling. New insights into the study of PMSAT problem have been gained since the introduction of the Max-SAT evaluations in 2006. Indeed, several PMSAT exact solvers have been developed based mainly on the Davis- Putnam-Logemann-Loveland （DPLL） procedure and Branch and Bound （B^B） algorithms. In this paper, we investigate and analyze a number of exact methods for PMSAT. We propose a taxonomy of the main exact methods within a general framework that integrates their various techniques into a unified perspective. We show its effectiveness by using it to classify PMSAT exact solvers which participated in the 2007~2011 Max-SAT evaluations, emphasizing on the most promising research directions.

关键词： Partial Max-SAT Davis-Putnam-Logenmann-Loveland branch and bound unsatisfiability pseudo-Boolean optimization

HDec-POSMDPs MRS Exploration and Fire Searching Based on IoT Cloud Robotics

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2020年第3期17卷 364-377页

作者： Ayman el Shenawy Khalil mohamed Hany Harb Systems and Computers Engineering Department Faculty of EngineeringAl-Azhar UniversityCairo 11751Egypt Information Technology College Misr University for Science and Technology(MUST)Cairo 77Egypt

The multi-robot systems(MRS)exploration and fire searching problem is an important application of mobile robots which require massive computation capability that exceeds the ability of traditional MRS′*** paper propose a cloud-based hybrid decentralized partially observable semi-Markov decision process(HDec-POSMDPs)*** proposed model is implemented for MRS exploration and fire searching application based on the Internet of things(IoT)cloud robotics *** this implementation the heavy and expensive computational tasks are offloaded to the cloud *** proposed model achieves a significant improvement in the computation burden of the whole task relative to a traditional *** proposed model is applied to explore and search for fire objects in an unknown environment;using different sets of robots *** preliminary evaluation of this implementation demonstrates that as the parallelism of computational instances increase the delay of new actuation commands which will be decreased,the mean time of task completion is decreased,the number of turns in the path from the start pose cells to the target cells is minimized and the energy consumption for each robot is reduced.

关键词： Multi-robot systems hybrid decentralized partially observable semi-Markov decision process(HDec-POSMDPs) multi-robot systems(MRS)exploration and fire searching cloud robotics cloud computing

Influence of host age and host deprivation on longevity, egg load dynamics and oviposition rate in Microplitis rufiventris

在线全文

学校读者我要写书评

暂无评论

Insect Science 2007年第6期14卷 485-495页

作者： ESMAT mohamed HEGAZI GEHAN mohamed ABD el-AZIZ AHMED YOUSEF el-SHAZLY WEDAD EMAM KHAFAG Department of Entomology Faculty of Agriculture University of Alexandria Plant Protection Research Institute Sabahia Alexandria Egypt

Adult size, longevity, egg load dynamics and oviposition ofMicroplitis rufiventris Kok. which began their development in the first, second, third （preferred hosts） or fourth （non-preferred hosts） instar larvae of Spodoptera littoralis （Boisd.） were studied. The parasitoid size was largely determined by the initial host size at parasitism. Non-ovipositing females derived from older hosts lived for longer periods than those derived from younger ones. However, the ovipositing females, irrespective of their size, lived for almost the same periods. At emergence, the oviducts of adult females contain a significant amount of mature eggs available for oviposition for a few hours on eclosion day. Egg load increases during the early phase of adult life. The amount of additional mature eggs and rate of egg maturation per hour was greater for wasps derived from preferred hosts compared with those in females derived from non-preferred hosts. The pattern of egg production in M. rufiventris females depended on the availability of hosts for parasitization. Host-deprived females depleted the egg complement with aging; the longer the host deprivation, the lower the oviduct egg load. Marked reduction in both realized or potential fecundity of host-deprived females was observed following host availability. Host privation for more than 3 days induced a marked deficit fecundity pattern through the female＇ s life. The realized fecundity was determined by the interaction among host availability, the number of eggs that are matured over the female＇ s life span, oviposition rate and host size from which the female was derived. These results suggest that：（i） M. rufiventris wasp is a weak synovigenic species; （ii） the maturation of additional eggs is inhibited once the maximum oviduct egg load is reached; （iii） the egg load of the newly emerged female is significantly less than the realized fecundity; and （iv） because M. rufiventris females oviposit fewer eggs when they begin depleting their

关键词： aging egg production host privation longevity Microplitis rufiventris,oviposition Spodoptera littoralis wasp size

Optimized system for combined production of electricity/green hydrogen for multiple energy pathways:a case study of Egypt

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Clean Energy 2024年第4期8卷 219-236页

作者： Reda Ragab mohamed HamdiHafez A.el Salmawy mohamed A.Ismail Mechanical Power Engineering Department Zagazig UniversityZagazig 44519Egypt Mechanical Engineering Department College of EngineeringKing Faisal UniversityAl-Ahsa 31982Saudi Arabia

By optimal sizing of a wind/photovoltaic hybrid renewable-energy(RE)system,trimming the surplus capacity to reduce the fluctuations in the electricity supplied to the grid,and using it to produce green hydrogen through electrolysis,a stable output with maximum possible capacity factor(CF)is generated to maintain the electricity grid ***,the trimmed energy is used in a secondary conversion path that minimizes the weighted average cost of the energy generated from the entire *** surplus power-to-gas conversion allows the use of green hydrogen to produce electricity,methanol,or ammonia subject to the resource availability,site characteristics,and financial *** on robust site selection criteria,the best performance is obtained at two sites:Ras Ghareb and Minya,achieving the lowest energy cost with some variance in their *** the Ras Ghareb site,the optimally sized RE plant provided the grid with a quasi-steady capacity of 423 MW with a CF of 80.04%and was capable of injecting 2965.8648 GWh throughout the year with the lowest cost of 2.4355¢/kWh.A surplus of 3.9%of the total energy produced from the plant was directed to produce 1922-ton H_(2)/year,achieving the lowest cost of hydrogen production of$1.9745/kg H_(2).For the other selected site,Minya,the clipped energy is used to produce 3330.47-ton H_(2)/year with an optimized lowest cost of$3.5268/kg H_(2).The difference in hydrogen costs was attributed to the number of full operating hours of the electrolyser in both *** cost is mainly affected by the electricity price and the electrolyser *** both tending to decrease,future forecasts show hydrogen cost reductions.

关键词： hybrid renewable-energy system(HRES) green hydrogen electrolysis power-to-gas methanol ammonia

The comparison of the Wnt signaling pathway inhibitor delivered electrospun nanoyarn fabricated with two methods for the application of urethroplasty

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 Materials Science 2016年第4期10卷 346-357页

作者： Xuran GUO Kaile ZHANG mohamed el-AASSAR Nanping WANG Hany el-HAMSHARY mohamed el-NEWEHY Qiang FU Xiumei MO State Key Lab for Modification of Chemical Fibers & Polymer Materials College of Chemistry & Chemical Engineering and Biotechnology Donghua University Shanghai 201620 China Department of Urology Affiliated Sixth People's Hospital Shanghai Jiaotong University Shanghai 200030 China Polymer Materials Research Department Advanced Technology and New Material Institute City of Scientific Research and Technological Applications (SRTA-City) New Borg El-Arab City Alexandria 21934 Egypt Shanghai Aquatic Product Research Institute Shanghai 200030 China Department of Chemistry College of Science King Saud University Riyadh i 1451 Saudi Arabia Department of Chemistry Faculty of Science Tanta University Tanta 31527 Egypt Shandong International Biotechnology Park Development Co. Ltd. Shanghai 200030 China

Urethral strictures were common disease caused by over-expression of extracellular matrix from fibroblast. In this study, we compare two nanoyarn scaffolds for improving fibroblasts infiltration without inhibition the over-expression of extracellular matrix. Collagenlpoly（L-lactide-co-caprolactone）（ColIP（LLA-CL）） nanoyarn scaffolds were prepared by conjugated electrospinning and dynamic liquid electrospinning, respectively, in addition, co-axial electrospinning technique was combined with the nanoyarn fabrication process to produce nanoyarn scaffolds loading Wntsignaling pathway inhibitor. The mechanical properties of the scaffolds were examined and morphology was observed by SEM. Cell morphology, proliferation and infiltration on the scaffolds were investigated by SEM, MTT assay and H＆E staining, respectively. The release profiles of different scaffolds were determined using HPLC. The results indicated that cells showed an organized morphology along the nanoyarns and considerable infiltration into the nanoyarn scaffolds prepared by dynamic liquid electrospinning （DLY）. It was also observed that the DLY significantly facilitate cell proliferation. The D-DLY could facilitate the infiltration of the fibroblasts and could be a promising scaffold for the treatment of urethra stricture while it may inhibit the collagen production.

关键词： biomaterials nanoyarn electrospinning inhibitor

A review on the multi-scaled structures and mechanical/thermal properties of tool steels fabricated by laser powder bed fusion additive manufacturing

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1048-1071页

作者： Huajing Zong Nan Kang Zehao Qin mohamed el Mansori Arts et Metiers Institute of Technology MSMPHESAM UniversitéChâlons-en-Champagne F-51006France Texas A&M Engineering Experiment Station Institute for Manufacturing SystemsCollege Station TX77843USA

The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds *** appearance of the LPBF makes it possible to design and produce complex conformal cooling channel systems in ***,LPBF-processed tool steels have attracted more and more *** complex thermal history in the LPBF process makes the microstructural characteristics and properties different from those of conventional manufactured tool *** paper provides an overview of LPBF-processed tool steels by describing the physical phenomena,the microstructural characteristics,and the mechanical/thermal properties,including tensile properties,wear resistance,and thermal *** microstructural characteristics are presented through a multiscale perspective,ranging from densification,meso-structure,microstructure,substructure in grains,to ***,a summary of tool steels and their challenges and outlooks are introduced.

关键词： additive manufacturing laser powder bed fusion tool steel multi-scaled structure mechanical properties thermal properties

Fibrolamellar hepatocellular carcinoma:A rare but unpleasant event

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2022年第6期14卷 1103-1114页

作者： Walaa Abdelhamed mohamed el-Kassas Department of Endemic Medicine Sohag UniversitySohag 14322Egypt Department of Endemic Medicine Faculty of MedicineHelwan UniversityCairo 11795Egypt

Fibrolamellar carcinoma(FLC)is a rare variant of hepatocellular carcinoma(HCC),comprising 1%–9%of all *** is a poorly understood malignancy,which seems to be more prevalent in young patients with no underlying liver *** term“fibrolamellar”is derived from thick fibrous collagen bands surrounding the tumor *** HCC,cirrhosis and viral hepatitis infection are not predisposing to FLC,and it is not associated with elevations in serum *** patients often present with vague abdominal pain,nausea,malaise,and weight *** cases present are at an advanced stage at the time of initial ***,curative treatment options can still be offered to up to 70%of ***(resection/liver transplantation)is the mainstay of treatment and the only potentially curative *** have been less chemoresponsive than the conventional HCC,however,in advanced cases,multimodality treatments can be *** advances in molecular studies of FLC have found a unique DNAJB1–PRKACA fusion transcript in most of the cases *** review aims to describe clinical characteristics,diagnostic methods,and therapeutic modalities for this rare tumor to raise awareness among clinicians and surgeons.

关键词： Fibrolamellar carcinoma Hepatocellular carcinoma Hepatitis Cirrhosis Viral hepatitis infection