检索结果-南通市图书馆

Effect of Nonlinear Convection on Stratified Flow of Third Grade Fluid with Revised Fourier-Fick Relations

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第7期69卷 25-30页

作者： m.Waqas m.Ijaz Khan T.Hayat A.Alsaedi Department of mathematics Quaid-I-Azam University Nonlinear Analysis and Applied mathematics (NAAm) Research Group Department of Mathematics Faculty of ScienceKing Abdulaziz University

Here thermal dependence conductivity and nonlinear convection features in third-grade liquid flow bounded by moving surface having varying thickness are formulated. Stagnation point flow is considered. Revised FourierFick relations and double stratification phenomena are utilized for modeling energy and concentration *** model of considered physical problem is achieved by implementing the idea of boundary layer theory. The acquired partial differential system is transformed into ordinary ones by employing relevant variables. The homotopic scheme yield convergent solutions of governing nonlinear expressions. Graphs are constructed for distinct values of physical constraints to elaborate the heat/mass transportation mechanisms.

关键词： nonlinear convection double stratification revised Fourier-Fick relations third grade liquid ther-mal dependence conductivity

Alcohol-induced steatosis in liver cells

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2007年第37期13卷 4974-4978页

作者： Terrence m Donohue Jr Liver Study Unit The Omaha Veterans Affairs Medical Center the Department of Internal Medicine University of Nebraska Medical Center Omaha Nebraska 68105 United States

Alcohol-induced fatty liver (steatosis) was believed to result from excessive generation of reducing equivalents from ethanol metabolism, thereby enhancing fat accumulation. Recent findings have revealed a more complex picture in which ethanol oxidation is still required, but specific transcription as well as humoral factors also have important roles. Transcription factors involved include the sterol regulatory element binding protein 1 (SREBP-1) which is activated to induce genes that regulate lipid biosynthesis. Conversely, ethanol consumption causes a general down-regulation of lipid (fatty acid) oxidation, a reflection of inactivation of the peroxisome proliferator- activated receptor-alpha (PPAR-α) that regulates genes involved in fatty acid oxidation. A third transcription factor is the early growth response-1 (Egr-1), which is strongly induced prior to the onset of steatosis. The activities of all these factors are governed by that of the principal regulatory enzyme, AmP kinase. Important humoral factors, including adiponectin, and tumor necrosis factor-α (TNF-α), also regulate alcohol-induced steatosis. Their levels are affected by alcohol consumption and by each other. This review will summarize the actions of these proteins in ethanol-elicited fatty liver. Because steatosis is now regarded as a significant risk factor for advanced liver pathology, an understanding of the molecular mechanisms in its etiology is essential for development of effective therapies.

关键词： Ethanol metabolism Fatty liver Sterolregulatory element binding protein Peroxisomeproliferator activated receptor Early growth response-i Fatty acid toxicity Triglycerides Acetaldehyde Reactiveoxygen species

Competition for shelter between four invasive gobiids and two native benthic fish species

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2011年第6期57卷 844-851页

作者： N. VAN KESSEL m. DORENBOSCH m.R.m. DE BOER R.S.E.W. LEUVEN G. VAN DER VELDE Radboud University Nijmegen Institute for Water and Wetland Research Department of Animal Ecology and Ecophysiology EO. Box 9010 6500 GL Nijmegen The Netherlands Radboud University Nijmegen Institute for Water and Wetland Research Department of Environmental Science P.O. Box 9010 6500 GL Nijmegen The Netherlands Natuurbalans - Limes Divergens P.O. Box 31070 6503 CB Nijmegen The Netherlands Netherlands Institute of Ecology （NIOO - KNAW） EO. Box 50 6700 AB Wageningen The Netherlands Netherlands Centre for Biodiversity Naturalis EO. Box 9517 2300 RA Leiden The Netherlands

Recent invasions by non-native gobiid fish species that are ongoing in the Western European rivers Rhine and meuse, will lead to interactions with native benthic fish species. Since both non-native gobiids and native benthic species are bottom dwelling species with a preference for shelter during at least part of their life cycle, it is likely that competition for shelter will occur between these non-native and native species when shelter is a limiting factor. To investigate the importance of this mecha- nism for species replacements, various habitat choice experiments were conducted between two common native benthic fish spe- cies （Cottus perifretum and Barbatula barbatula） and four invasive non-native gobiid species （Proterorhinus semilunaris, Neogo- bius melanostomus, N. kessleri and N. fluviatilis）. The first series of single specimen experiments determined the habitat choice of each individual fish species. In a second series of competition experiments, shifts in habitat choice in comparison with the previ- ously observed habitat choice, were determined when a native benthic fish species co-occurred with non-native gobiid species. Native C. perifretum displayed a significant shift in habitat choice in co-occurrence with the gobiids N. kessleri or P. semilunaris. C. perifretum was outcompeted and moved from the available shelter place to less preferred habitat types. During the competition experiments no change in habitat choice of B. barbatula was shown. Our study therefore suggests that competition for shelter is likely to occur in rivers invaded by N. kessleri and P. semilunaris at sites where shelter is limiting

关键词： Bullhead Exotic species Habitat choice Invasive gobies Rivers Rhine and meuse Stone loach

Simulating the stress–strain state of a thin plate after a thermal shock

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of modeling, Simulation, and Scientific Computing 2022年第3期13卷 245-254页

作者： A.V.Sedelnikov S.V.Glushkov V.V.Serdakova m.A.Evtushenko E.S.Khnyryova Samara National Research University 34 Moskovskoye ShosseSamara 443086 Samarskaya OblastRussia Amur State University 21Ignat’yevskoye Shosse Blagoveshchensk 675027Amurskaya OblastRussia

The paper is devoted to simulating the impact of a thermal shock on a thin homogeneous plate in the ANSYS *** assessment of the stress–strain state is carried out and the dynamics of changes in the temperature field of the plate is *** obtained results were compared with the data of other authors and can be used when taking into account the thermal shock of large elastic elements of spacecraft.

关键词： Thermal shock thin plate stress-strain state temperature field

Changes in oral trace gas concentrations following orthognathic surgery and intermaxillary fixation: a case study using selected ion flow tube mass spectrometry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Oral Science 2011年第3期3卷 160-164页

作者： Brian m. Ross Division of medical Sciences at the Northern Ontario School of medicine in Thunder Bay Ontario MS 3002 Canada

Orthognathic surgery is frequently accompanied by intermaxillary fixation. Intermaxillary fixation impedes the maintenance of effective oral hygiene and prolonged fixation can result in periodontal disease. A potential shorter term effect is the generation of oral malodour. It is unclear, however, as to how the production of malodorous compounds in the oral cavity is altered post-surgery. Oral air concentration of sulphur containing compounds, short chain organic acids, ammonia, isoprene and acetone were measured using selected ion flow tube-mass spectrometry in a patient who had undergone orthognathic surgery with subsequent intermaxillary fixation. Total sulphide levels rose approximately 5-fold during fixation with metal ties, with smaller increases recorded for the other compounds measured with the exception of isoprene which remained close to baseline levels. Organic acid levels declined markedly once elastic ties had replaced metal ties, with a lesser reduction being observed in sulphide levels, with both declining further after the commencement of a chlorhexidinecontaining mouthwash. These data suggest that bacterial generation of a variety of malodorous compounds increases markedly following intermaxillary fixation. This single case also suggests that the use of elastic ties and effective oral hygiene techniques, including the use of chlorhexidine mouthwash, may help ameliorate such post-surgical effects.

关键词： oral malodour halitosis oral hygiene breath analysis organic acids sulphides mass spectrometry

Improvement of mechanical Properties of Cr-Ni-mo-Cu-Ti Stainless Steel With Addition of Vanadium

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2007年第6期14卷 74-78页

作者： S m Abbasi A Shokuhfar Advanced materials Research Laboratory K. N. Toosi University of Technology Tehran 165698391 Iran

The effect of vanadium （V） addition on the mechanical properties of a Cr-Ni-mo-Cu-Ti stainless steel was studied and its influence on microstructural changes was also investigated. Results indicate that the structure of the solution-treated specimens mainly comprises of austenite-martensite, and adding V leads to the formation of a consid erable amount of ferrite. Under this condition, austenite phase is not mechanically stable, and transforms to martensite by plastic deformation. The addition of 0.5% - 1.0% （in mass percent） of V increases the hardness and the strength of the 80% cold rolled and aged steel, without any effect on ductility. Improvement in mechanical properties is presumably attributed to the formation of a small amount of ferrite in the primary structure, and the formation of certain precipitates is accelerated by the addition of V during aging. By contrast, excessive V decreases the strength and ductility simultaneously. This is due to the strong effect of ferrite formation compared to the beneficial effect of precipitation. The loss of ductility caused by adding higher amount of V is due to the formation of ferrite phases which in turn are suitable nucleation sites for crack propagation.

关键词： stainless steel vanadium microstructure mechanical property

Do Research Incentives Promote Researchers’mental Health?

在线全文

学校读者我要写书评

暂无评论

International Journal of mental Health Promotion 2023年第8期25卷 903-914页

作者： Liujian Gu Tao Wang Chuanyi Wang m.James CCrabbe Xiao-Guang Yue Institute of Education Tsinghua UniversityBeijing100084China Wolfson College Oxford UniversityOxfordOX26UDUK Department of Computer Science and Engineering European University CyprusNicosia1516Cyprus

Background:Researchers have a higher risk of anxiety and depression than the general population,so it is important to promote researchers’mental ***:Based on the data from 3210 global researchers surveyed by the journal Nature in 2021,confirmatory factor analysis,OLS regression and other regressions were used to explore the research incentive dimensions and their effects on researchers’mental ***:(1)material incentive factors,work-family life balance factors,good organizational environment and spiritual motivation had significant positive effects on researchers’mental health.(2)The spiritual motivation could better promote researchers’mental health than the other factors.(3)Heterogeneity analysis showed that material incentive factors and spiritual motivation created more significant stimulating effects on the mental health of humanities and social sciences ***-family life balance factors were more effective in promoting the mental health of the mid-career group and the overtime ***:Application of the four research incentives resulted in lower likelihood of anxiety or depression among researchers,and special attention should be paid to the role of the spiritual *** order to promote researchers’mental health,different incentives should be applied to different researcher groups to better improve researchers’mental health.

关键词： Researchers mental health research incentive

Volatility spillovers,structural breaks and uncertainty in technology sector markets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Financial Innovation 2023年第1期9卷 2908-2938页

作者： Linn Arnell Emma Engström Gazi Salah Uddin mdBokhtiar Hasan Sang Hoon Kang Landshypotek Bank StockholmSweden Department of management and Engineering Linköping UniversityLinköpingSweden Department of Finance and Banking Islamic UniversityKushtia 7003Bangladesh School of Business Pusan National UniversityBusanRepublic of Korea

This study uses the dynamic conditional correlation to investigate how technology subsector stocks interact with financial assets in the face of economic and financial *** results suggest that structural breaks have diverse effects on financial asset connectedness and that the level of bond linkage increases when the trend *** see a growing co-movement between the technology sector and major financial assets when uncertainty is ***,our findings indicate that the connectedness response varies depending on the type of uncertainty shock.

关键词： Technology sector Diversification Dynamic conditional correlation Uncertainty Structural breaks

Furrow design for improving crop establishment of two-wheel tractor operated strip tillage planters in loam and clay loam soils

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2021年第3期14卷 130-139页

作者： m.Arshadul Hoque m.m.Hossain A.T.m.Ziauddin Timothy J.Krupnik mahesh K.Gathala Senior Scientific Officer FMP Engineering DivisionBangladesh Agricultural Research InstituteGazipur-1701Bangladesh Department of Farm Power and machinery Bangladesh Agricultural UniversityMymensingh-2202Bangladesh International maize and Wheat Improvement Center-Bangladesh Dhaka-1213Bangladesh

Conservation agriculture(CA)based production systems may help in achieving more sustainable intensification of cropping systems that use less labour and energy and have higher profit margins,in addition to soil conservation and environmental impact mitigation *** these objectives can only be achieved when the right mechanization options,including appropriate crop establishment equipment,are in place to assist in timely field *** urgent need exists,therefore,to fine tune and re-adjust the existing two-wheel tractor(2WT)operated seed drills,with specific reference to the design of blade and furrow openers,while at the same time considering performance in different soil types and *** this end,experiments were conducted during 2013-2014 and 2014-2015 at two BARI Regional Agricultural Research Stations in Jamalpur and Barisal,Bangladesh,on a loam and clay loam soil,respectively,to evaluate five types of furrow opener for strip *** and modified shoe-type furrow openers were tested and compared with three inverted-T furrow openers with rake angles of 75°,65°and 55°.The newly designed inverted-T furrow openers were narrower than the shoe-type openers;they also had a longer,hollow shanks and provided better options for adjustment to achieve the desired seeding depth and line *** to shoe-type openers,better seeding depth,uniformity and higher degree of seed coverage were recorded with use of the inverted-T furrow opener with a 65°rake *** resulted in better seed coverage in the furrow,a higher emergence rate index,and the highest emergence percentage of maize and mung *** research findings can be generalized to smallholder production systems on loam and clay loam soils where farmers utilize 2WT operated seed drills for crop establishment in both traditional and conservation agriculture-based planting systems.

关键词： two-wheel tractor strip tillage planter inverted-T furrow opener rake angle conservation agriculture emergence percentage