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Frictional contact problem for elastic-viscoplastic materials with thermal effect

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Applied mathematics and mechanics(English Edition) 2013年第6期34卷 761-776页

作者： m. SElmANI l. SElmANI Department of mathematics University of Setif

A dynamic contact problem for elastic-viscoplastic materials with thermal effects is investigated. The contact is bilateral, and the friction is modeled with Tresca＇s friction law with heat exchange. A variational formulation of the model is derived, and the existence of a unique weak solution is proved. The proofs are based on the classical result of nonlinear first order evolution inequalities, the equations with monotone operators, and the fixed point arguments. Finally, the continuous dependence of the solution on the friction yield limit is studied.

关键词： thermo-elasto-viscoplastic material dynamic process bilateral contact,Tresca's friction evolution inequality evolution equation weak solution fixed point

Assessing the reproductive health of men with occupational exposures

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Asian Journal of Andrology 2014年第1期16卷 23-30页

作者： Steven m Schrader Katherine l marlow Centers for Disease Control and Prevention National Institute for Occupational Safety and Health Division of Applied Research and Technology Cincinnati OH USA.

The earliest report linking environmental （occupational） exposure to adverse human male reproductive effects dates back to1775 when an English physician, Percival Pott, reported a high incidence of scrotal cancer in chimney sweeps. This observation led to safety regulations in the form of bathing requirements for these workers. The fact that male-mediated reproductive harm in humans may be a result of toxicant exposures did not become firmly established until relatively recently, when lancranjan studied lead-exposed workers in Romania in 1975, and later in 1977, when Whorton examined the effects of dibromochloropropane （DBCP） on male workers in California. Since these discoveries, several additional human reproductive toxicants have been identified through the convergence of laboratory and observational findings. many research gaps remain, as the pool of potential human exposures with undetermined effects on male reproduction is vast. This review provides an overview of methods used to study the effects of exposures on male reproduction and their reproductive health, with a primary emphasis on the implementation and interpretation of human studies. Emphasis will be on occupational exposures, although much of the information is also useful in assessing environmental studies, occupational exposures are usually much higher and better defined.

关键词： accessory glands endocrine epidemiology semen sexual function sperm testis toxicology

modeling regional landslide susceptibility using dynamic soil moisture profiles

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Journal of mountain Science 2018年第8期15卷 1807-1824页

作者： RAY Ram l JACOBS Jennifer m DOUGlAS Ellen m Cooperative Agricultural Research Center College of Agriculture and Human Sciences Prairie View A&M University Department of Civil Engineering University of New Hampshire Environmental Earth and Ocean Sciences Department University of Massachusetts Boston

A landslide susceptibility mapping study was performed using dynamic hillslope hydrology. The modified infinite slope stability model that directly includes vadose zone soil moisture(Sm) was applied at Cleveland Corral, California, US and Krishnabhir, Dhading, Nepal. The variable infiltration capacity(VIC-3l) model simulated vadose zone soil moisture and the wetness index hydrologic model simulated groundwater(GW). The GW model predictions had a 75% NASH-Sutcliffe efficiency when compared to California's in-situ GW measurements. The model performed best during the wet season. Using predicted GW and VIC-3l vadose zone Sm, the developed landslide susceptibility maps showed very good agreement with mapped landslides at each study region. Previous quasi-dynamic model predictions of Nepal's hazardous areas during extreme rainfall events were enhanced to improve the spatial characterization and provide the timing of hazardous conditions.

关键词： landslide susceptibility Vadose zone Soil moisture Infiltration eapacity VIC-3l Groundwater

A Search on Dirac Equation

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Chinese Physics letters 2007年第11期24卷 3024-3027页

作者： m. Kocak, B. Gonül Department of Engineering Physics Faculty of Engineering University of Gaziantep 27310 Gaziantep Turkey

The solutions, in terms of orthogonal polynomials, of Dirac equation with analytically solvable potentials are investigated within a novel formalism by transforming the relativistic equation into a Schrodinger-like one. Earlier results are discussed in a unified framework, and some solutions of a large class of potentials are given.

关键词： coated conductor buffer layer self-epitaxy CeO2

Remarks on Exact Solvability of Quantum Systems with Spatially Varying Effective mass

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Chinese Physics letters 2005年第11期22卷 2742-2745页

作者： B. Goenül m. Kocak Department of Engineering Physics Faculty of Engineering University of Gaziantep 27310 Gaziantep Türkiye

Within the frame of a novel treatment we make a complete mathematical analysis of exactly solvable onedimensional quantum systems with non-constant mass, involving their ordering ambiguities. This work extends the results recently reported in the literature and clarifies the relation between physically acceptable effective mass Hamiltonians.

关键词： DEPENDENT EFFECTIVE mASSES SUPERSYmmETRIC APPROACH SCHRODINGER-EQUATION PERTURBATION-THEORY POTENTIAlS SEmICONduCTORS STATES

Solder Size Effect on Early Stage Interfacial Intermetallic Compound Evolution in Wetting Reaction of Sn3.0Ag0.5Cu/ENEPIG Joints

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Journal of materials Science & Technology 2015年第3期31卷 252-256页

作者： m.l.Huang F.Yang Electronic Packaging materials laboratory School of Materials Science & Engineering Dalian University of Technology

Solder size effect on early stage interfacial intermetallic compound(ImC) evolution in wetting reaction between Sne3.0Age0.5Cu solder balls and electroless nickel electroless palladium immersion gold(ENEPIG) pads at 250 C was investigated. The interfacial ImCs transformed from initial needle- and rodtype(Cu,Ni)6Sn5to dodecahedron-type(Cu,Ni)6Sn5and then to needle-type(Ni,Cu)3Sn4at the early interfacial reaction stage. moreover, these ImC transformations occurred earlier in the smaller solder joints, where the decreasing rate of Cu concentration was faster due to the Cu consumption by the formation of interfacial(Cu,Ni)6Sn5. On thermodynamics, the decrease of Cu concentration in liquid solder changed the phase equilibrium at the interface and thus resulted in the evolution of interfacial ImCs; on kinetics, larger solder joints had sufficient Cu flux toward the interface to feed the(Cu,Ni)6Sn5growth in contrast to smaller solder joints, thus resulted in the delayed ImC transformation and the formation of larger dodecahedron-type(Cu,Ni)6Sn5grains. In smaller solders, no spalling but the consumption of(Cu,Ni)6Sn5grains by the formation of(Ni,Cu)3Sn4grains occurred where smaller discrete(Cu,Ni)6Sn5grains formed at the interface.

关键词： Size effect lead-free solder Interfacial reaction

magnesium Uptake and Palygorskite Transformation Abilities of Wheat and Oat

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Pedosphere 2012年第6期22卷 834-841页

作者： m.H.SAlEHI l.TAHAmTANI Department of Soil Science College of AgricultureShahrekord UniversityShahrekord(Iran)

Weathering of clay minerals is a source of nutrients to plants. Palygorskite is a mg-rich fibrous clay mineral that commonly occurs in the soils and sediments of arid regions. Although many studies have examined the environmental conditions required for the formation and stability of palygorskite, information on the transformation of this mineral in the root zone （or rhizosphere） of agricultural crops is limited. This study explored the possibility of palygorskite transformation in the rhizosphere of wheat and oat and compared the ability of these crops to extract structural mg from palygorskite. The crops were cultivated in pots consisting of a mixture of sand from Hamadan region, Iran and Florida palygorskite, irrigated with distilled water, and treated with either complete or mg-free nutrient solutions. After 100 d, mg uptake by the crops was measured. Clay-sized particles in each pot were also separated from the sand and were analyzed through X-ray diffraction （XRD）. The X-ray pattern of the particles was compared with that of the pure palygorskite particles （before cultivation）. The results showed that palygorskite could provide sufficient mg for the growth of wheat in the pots supplied with mg-free nutrient solution. In spite of the magnesium uptake by both plants from the palygorskite structure, no detectable peaks indicating the transformation of pmygorskite were recognized by XRD. A decrease of 1.05 nm in peak intensity was more obvious for the pots containing palygorskite and irrigated with mg-free nutrient solution than for the pots irrigated with complete nutrient solution. Although the decrease in peak intensity was greater for oat than wheat, indicating greater palygorskite weathering by oat, mg uptake by oat was low, as evidenced by the deficiency symptoms observed.

关键词： clay minerals nutrient solution rhizosphere weathering X-ray diffraction

Evaluation of clinical relevance of examining K-ras, p16 and p53 mutations along with allelic losses at 9p and 18q in EUS-guided fine needle aspiration samples of patients with chronic pancreatitis and pancreatic cancer

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World Journal of Gastroenterology 2007年第27期13卷 3714-3720页

作者： C Salek l Benesova m Zavoral V Nosek l Kasperova m Ryska R Strnad E Traboulsi m minarik Department of Gastroenterology Central Military Hospital and 1~(st) Medical Faculty of Charles University Prague Czech Republic Laboratory for Molecular Genetics and Oncology Genomac International Ltd. Prague Czech Republic Department of Gastroenterology Institute for Postgraduate Medical Education Prague Czech Republic laboratory for molecular Genetics and Oncology Genomac International Ltd. Prague Czech Republic Department of Gastroenterology Central Military Hospital and 1~(st) Medical Faculty of Charles University Prague Czech Republic Department of Gastroenterology Institute for Postgraduate Medical Education Prague Czech Republic Department of Gastroenterology Central Military Hospital and 1~(st) Medical Faculty of Charles University Prague Czech Republic Department of Surgery Central Military Hospital and 2nd Medical Faculty of Charles University Prague Czech Republic Department of Pathology Central Military Hospital Prague Czech Republic

AIm： To establish an optimum combination of molecular markers resulting in best overall diagnostic sensitivity and specificity for evaluation of suspicious pancreatic mass. mETHODS： Endoscopic ultrasound （EUS）-guided fine needle aspiration cytology （FNA） was performed on 101 consecutive patients （63 males, 38 females, 60 ± 12 years; 81 with subsequently diagnosed pancreatic cancer, 20 with chronic pancreatitis） with focal pancreatic mass. Samples were evaluated on-site by an experienced cytopathologist. DNA was extracted from Giemsa stained cells selected by laser microdissection and the presence of K-ras, p53 and p16 somatic mutations was tested by cycling-gradient capillary electrophoresis （CGCE） and single-strand conformation polymorphism （SSCP） techniques. In addition, allelic losses of tumor suppressor genes p16 （INK4, CDKN2A） and DPC4 （mADH4, SmAD4） were detected by monitoring the loss of heterozygosity （lOH） at 9p and 18q, respectively. RESUlTS： Sensitivity and specificity of EUS-guided FNA were 75% and 85%, positive and negative predictive value reached 100%. The remaining 26% samples were assigned as inconclusive. Testing of molecular markers revealed sensitivity and specificity of 70% and 100% for K-ras mutations （P 〈 0.001）, 24% and 90% for p53 mutations （NS）, 13% and 100% for p16 mutations （NS）, 85% and 64% for aUelic losses at 9p （P 〈 0.001） and 78% and 57% for allelic losses at 18q （P 〈 0.05）. When tests for different molecular markers were combined, the best results were obtained with K-ras ＋ lOH at 9p （92% and 64%, P 〈 0.001）, K-ras ＋ lOH at 18q （92% and 57%, P 〈 0.001）, and K-ras ＋ lOH 9q ＋ lOH 18q （96% and 43%, P 〈 0.001）. When the molecular markers were used as complements to FNA cytology to evaluate inconclusive samples only, the overall sensitivity of cancer detection was 100% in all patients enrolled in the study. CONClUSION： EUS-guided FNA cytology combined with screening of K-ras mutations and allelic losses of tumor suppressors p16 and

关键词： Pancreatic cancer Chronic pancreatitis Endoscopic ultrasound-guided fine-needle aspiration molecular markers loss of heterozygosity

Repeatability of decision-making behaviour in male threespine stickleback Gasterosteus aculeatus： Effects of dummy vs. live stimuli

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Current Zoology 2011年第1期57卷 101-108页

作者： Teresa l. DZIEWECZYNSKI lindsay m. FORRETTE Department of Psychology University of New England 11 Hills Beach Rd Biddeford ME 04005 USA

Individuals select from a number of behaviours when responding to various situations and the decisions they make may affect their fitness. The costs and benefits of these responses vary among individuals causing them to differ even in identical situations. One example of this type of situation is when territorial males encounter both a male and female simultaneously, gene- rating a trade-off that likely leads to individual differences due to differing costs of various actions among males. This situation commonly occurs in threespine stickleback, Gasterosteus aculeatus. However, for selection to act effectively, individuals must behave in a consistent manner and measuring repeatability can aid in understanding how selection may shape such trade-offs. males of this species exhibit consistent individual differences in their response to dummy males and females but it is unknown ff patterns are similar when feedback from the stimuli is present. To assess this, male threespine stickleback were tested with dummy and live male and female conspecifics, presented separately and simultaneously. While the same trends were found re- gardless of stimulus type, males were more aggressive towards the live conspecifics than to the dummies. Repeatability values were similar within a treatment regardless of whether live or dummy conspecifics were used, suggesting that individuals show the same level of consistency. This study adds to our understanding of consistent individual differences by demonstrating that feed- back may not affect responses to conflicting stimuli and that male threespine stickleback respond in a consistent manner to both dummy and live stimuli

关键词： Decision-making Stimulus efficacy Behavioural consistency Repeatability Threespine stickleback