检索结果-南通市图书馆

Influence of Heat Input on martensite Formation and Impact Property of Ferritic-Austenitic Dissimilar Weld metals

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2012年第4期28卷 343-352页

作者： m. mukherjee T.K. Pal Welding Technology Centre Metallurgical and Material Engineering Department Jadavpur University

The effect of heat input on martensite formation and impact properties of gas metal arc welded modified ferritic stainless steel （409m） sheets （as received） with thickness of 4 mm was described in detail in this work. The welded joints were prepared under three heat input conditions, i.e. 0.4, 0.5 and 0.6 kJ/mm using two different austenitic filler wires （308L and 316L） and shielding gas composition of Ar ＋ 5% CO2. The welded joints were evaluated by microstructure and charpy impact toughness. The dependence of weld metal microstructure on heat input and filler wires were determined by dilution calculation, Creq/Nieq ratio, stacking fault energy （SFE）, optical microscopy （om） and transmission electron microscopy （TEm）. It was observed that the microstructure as well as impact property of weld metal was significantly affected by the heat input and filler wire. Weld metals prepared by high heat input exhibited higher amount of martensite laths and toughness compared with those prepared by medium and low heat inputs, which was true for both the filler wires. Furthermore, 308L weld metals in general provided higher amount of martensite laths and toughness than 316L weld metals.

关键词： Heat input Ferritic-austenitic dissimilar weld martensite Grain size Toughness

Effects of High Voltage and Flow rate Parameters on Nanofibers Diameter Synthesis by Electrospinning Technique

在线全文

学校读者我要写书评

暂无评论

Journal of Physical Science and Application 2016年第1期6卷 123-130页

作者： Akram r. Jabur Laith K. Abass Safa m. muhiAldain Department of materials Engineering University of Technology Baghdad Iraq

Electrospinning has recently emerged as a leading technique for generating biomimetic scaffolds made of synthetic and natural polymers for tissue engineering applications. In this study, we prepared polyvinyl alcohol （PVA） solution as biopolymer material for fabrication of scaffolds tissue by electrospiuning, we optimized the shape and size of the ensuing electrospun fibers by varying of the electrospinning process, such as high voltage with 5-25 kV and polymeric solution rate with 0.2-10 ml/h. Scanning electron microscopy was utilized the topography of individual electrospun fibers. Distribution of mean diameters of the synthesis fibers were measured fi＇om scanning electron micrographs. Fibers diameters size related with fibers a count in SEm images as gaussian distribution with maximum peak represented the average fibers diameters. Our results indicate that the average diameter PVA fibers could be scaled down to mean values 80-500 nm without any beads, fibers diameter increased as applied voltage decreased and decrease as polymeric solution flow rate increase to be with 300-580 nm as mean diameters.

关键词： Electrospinning naniofibers synthesis high voltageand flow rate.

Skin layer of A380 aluminium alloy die castings and its blistering during solution treatment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2019年第9期35卷 1906-1916页

作者： Zihao Yuan Zhipeng Guo S.m.Xionga School of materials Science and Engineering Tsinghua UniversityBeijing100084China State Key Laboratory of Automobile Safety and Energy Tsinghua UniversityBeijing100084China

Skin layer is a characteristic microstructure of aluminium die castings, which would effect the surface blistering during solution treatment. In this study, the microstructures of skin layer were investigated by the methods of optical microscope (om), scanning electron microscope (SEm) and electron probe microanalyzer (EPmA). High resolution X-ray CT was used to compare the skin layer with normal surface before and after solution treatment. With the aid of computational fluid dynamics (CFD), the formation mechanism of the skin layer was discussed based on microstructure distribution, solute segregation, porosity distribution and surface blistering. The results suggested that the skin layer is related to a succession of complex processes before the filling process finished. Pore clusters or laminar defects would be formed in skin layers during solution treatm ent and cause severe surface blistering.

关键词： Skin layer Die castings Solution treatment Blistering

Square-root parametrization of dark energy in f(Q)cosmology

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2023年第12期75卷 105-114页

作者： m Koussour N myrzakulov Alnadhief H A Alfedeel E I Hassan D Sofuoğlu Safa m mirgani Quantum Physics and magnetism Team LPMCFaculty of Science Ben M'sikCasablanca Hassan II University L.N.Gumilyov Eurasian National University ratbay myrzakulov Eurasian International Centre for Theoretical Physics Department of mathematics and Statistics Imam Mohammad Ibn Saud Islamic University(IMSIU) Department of Physics Faculty of ScienceUniversity of Khartoum Centre for Space research North-West University Department of Physics Istanbul University Vezneciler 34134

This paper is a parametrization of the equation of state(Eo S)parameter of dark energy(DE),which is parameterized using square-root(Sr)form i.e.ω_(Sr)=ω_(0)+ω_(1)z/√z^(2)+1,where ω_(0)and ω_(1) are free *** parametrization is examined in the context of the recently suggested f(Q)gravity theory as an alternative to general relativity(Gr),in which gravitational effects are attributed to the non-metricity scalar Q with the functional form f(Q)=Q+αQ^(n),whereαand n are arbitrary *** derive observational constraints on model parameters using the Hubble dataset with 31 data points and the Supernovae(SNe)dataset from the Pantheon samples compilation dataset with 1048 data *** the current model,the evolution of the deceleration parameter,density parameter,EoS for DE,and om(z)diagnostic have all been *** has been shown that the deceleration parameter favors the current accelerated expansion *** has also been shown that the EoS parameter for DE has a quintessence nature at this time.

关键词： cosmology dark energy f(Q)gravity EoS parameter

microscopic Characterization of Ecological Concrete Polymeric

在线全文

学校读者我要写书评

暂无评论

microscopy research 2014年第1期2卷 13-17页

作者： A. D. rodríguez m. L. Domínguez r. m. melgoza Centro de Investigación en Ingeniería y Ciencias Aplicadas Universidad Autónoma del Estado de Morelos Cuernavaca México Facultad de Ciencias Químicas e Ingeniería Universidad Autónoma del Estado de Morelos Cuernavaca México.

The Scanning Electron microscopy (SEm) and Optical microscopy (om) with integrated digital camera are techniques that are used in the present investigation, for the morphological characterization of a new composite material called “organic polymer concrete” in which microparticles added fibers and polyethylene terephthalate (PET) recycling mechanically (rm). Polymer concrete (PC) is a new composite material (mC) in the application considered as an alternative material of construction in which reinforcement particles are recycled polymers which have approximately the same dimensions in all directions. Therefore, the particles can be rods, spheres, chips and many other shapes whose appearance reasons are about 10 microns. These mC, the size, shape and distribution and the ratio and the modulus of the particles affect the properties of the material.

关键词： Polymer Concrete Polymer Blend

Effect of doping concentration on the performance of solar cell constructed from (muscovite/TiO<sub>2</sub>/Dye/Al)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Natural Science 2013年第1期5卷 52-56页

作者： r. Abd Elgani m. H. m. HILO A. Al Hassan m. D. Abd Allah Department of Physics Faculty of Education Al-Zaiem Al-Azhari University Om Durman Sudan Department of Physics Faculty of Science Sudan University of Science and Technology Khartoum Sudan

Solar cells were fabricated from (muscovite/ TiO2/Dye/Al), the effect of temperature, concen- tration and light intensity on the electrical prop- erties of (muscovite/TiO2/Dye/Al) was studied. The relationship between current and voltage was found to be algorism, which is in agreement with the ordinary relation for solar cells. When dye concentration was increased the conductivity, fill factor and efficiency were also increased. This result is found to be in conformity with the theoretical relations. The small energy gaps for their samples show that they are semiconductors. The maximum efficiency obtained is 33.2%.

关键词： Solar Cell Conductivity Fill Factor Efficiency muscovite

Extruded Corn meal as a Partial replacement for Steam Flaked Corn in Finishing Diets for Feedlot Cattle: Growth Performance and Digestive Function of Feedlot Cattle

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Animal Sciences 2019年第2期9卷 196-206页

作者： L. Buenabad A. Y. Jacinto m. montano r. A. Zinn Department of Nutrition and Biotechnology of ruminats Instituto de Investigaciones en Ciencias Veterinarias Universidad Autónoma de Baja California Mexicali Mexico Department of Animal Science University of California Davis USA

Sixty-four Holstein steers (247 ± 4 kg) were used in a 70-d experiment to evaluate the effects of partial replacement of steam flake corn (SFC) with extruded corn meal (EC) on growth performance and dietary net energy. Treatments consisted of a steam flaked corn-based finishing diet containing 0%, 10%, 20%, or 30% EC, where EC replaced 0%, 15%, 30%, or 45% of SFC (Dm basis). replacement of SFC with increasing levels of EC did not affect (P > 0.10) ADG, DmI, and gain efficiency. When EC replaced 15% to 30% of SFC, observed dietary NE was 99% of expected. Whereas, when EC replaced 45% of SFC, observed dietary NE was 94% of expected. Four Holstein steers (210 ± 7 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate treatment effects on characteristics of digestion. Partial replacement of SFC with EC did not affect (P > 0.10) flow of undegraded feed N and microbial N and to the small intestine, and ruminal microbial N efficiency (g microbial N/kg om fermented). Likewise, there were no treatment effects (P > 0.10) on ruminal digestion of om, NDF, starch and feed N. As expected, total tract digestion of starch for all treatments exceeded 99%. However, partial replacement of SFC with EC decreased total tract digestion of Dm and om (linear effect, P = 0.02), and dietary DE (linear effect, P = 0.03). These effects were more pronounced where EC replaced 45% of SFC. Partial replacement of SFC with EC did not affect (P > 0.10) ruminal pH, total VFA concentration, molar proportions of acetate, propionate, and butyrate, and estimated methane production. It is concluded that partial replacement of SFC with EC does not have a beneficial effect on ruminal microbial efficiency and digestive function. The feeding value of extruded corn for feedlot cattle is comparable to that of steam flaked corn provided the inclusion rate does not exceed 20% of diet dry matter.

关键词： Corn Grain Extruded Steam Flaked Feedlot Cattle

A Biobank for Long-term and Sustainable research in the Field of Congenital Heart Disease in Germany

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2016年第4期14卷 181-190页

作者： Thomas Pickardt Eva Niggemeyer Ulrike m.m.Bauer Hashim Abdul-Khaliq Competence Network for Congenital Heart Defects Investigators National register for Congenital Heart Defects 13353 BerlinGermany Saarland University medical Center Department of Paediatrie Cardiology66421 HomburgGermany Competence Network for Congenital Heart Defects 13353 BerlinGermany

Congenital heart disease （Chd） is the most fi＇equent birth defect （0.8% 1% of all live births）. Due to the advance in prenatal and postnatal early diagnosis and treatment, more than 90% of these patients survive into adulthood today. However, several mid- and long-term morbidi- ties are dominating the follow-up of these patients. Due to the rarity and heterogeneity of the phenotypes of Chd, multicenter registry-based studies are required. The Chd-Biobank was established in 2009 with the aim to collect DNA from patients and their parents （trios） or fi＇om affected families, as well as cardiovascular tissues from patients undergoing corrective heart surgery for cardiovascular malformations. Clinical/phenotype data are matched to the International Paediatric and Congenital Cardiac Code （IPCCC） and the International Statistical Classification of Diseases and related Health Problems 10th revision （ICD-10）. The DNA collection currently com.rises samples from approximately 4200 participants with a wide range of Chd phenotypes. The collection covers about 430 trios and 120 families with more than one affected member. The cardiac tissue collection com.rises 1143 tissue samples [Yore 556 patients alter open heart surgery. The Chd-Biobank provides a com.rehensive basis for research in the field of Chd with high standards of data privacy, IT management, and sample logistics.

关键词： Congenital heart defects multi-center research Biorepository Genetic research DNA

Optical bistability and multistability in a defect slab doped by GaAs/AlGaAs multiple quantum wells

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第5期25卷 223-228页

作者： Seyyed Hossein Asadpour G Solookinejad m Panahi E Ahmadi Sangachin Department of Physics Marvdasht Branch Islamic Azad University

We proposed a new model for controlling the optical bistability（OB） and optical multistability（om） in a defect slab doped with four-level GaAs/AlGaAs multiple quantum wells with 15 periods of 17.5 nm GaAs wells and 15-nm Al_（0.3）Ga_（0.7）As barriers. The effects of biexciton energy renormalization, exciton spin relaxation, and thickness of the slab on the OB and om properties of the defect slab were theoretically investigated. We found that the transition from OB to om or vice versa is possible by adjusting the controllable parameters in a lab. moreover, the transmission, reflection, and absorption properties of the weak probe light through the slab were also discussed in detail.

关键词： optical bistability optical multistability quantum well nanostructure