检索结果-南通市图书馆

A STUDY OF DIRECTIONALITY OF LATENT HARDENING BEHAVIOR IN ALUMINIUM SINGLE CRYSTALS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1996年第3期9卷 246-252页

作者： Wang, MZ Shi, L Li, ch Xiao, JM UNIV SCI & TEchNOL BEIJING DEPT MAT PHYSBEIJING 100083PEOPLES R CHINA

By defining the yield stress in a latent hardening test as the first deviation from the elastic straight line, the yielding and hardening behavior on a latent system in the positive and negative slip direction was studied in aluminium single crystals. It is shown that the yield stresses on both the positive and negative latent systems are about equal to or a little lower than the maximum resolved shear stress in the primary test, but much higher than that of the active system. The Influence of relative orientation and prestrain on latent hardening and initial work-hardening in the secondary test was also investigated, and it was found that there is a considerable effect on initial work-hardening, but none on latent hardening. With reasonable approximation, a hardening rule for single crystal could be proposed from the experimental results, that is, except for the yield stress on the system negative to the active system that is very low, hardening on the other systems is nearly the same as self-hardening.

关键词： latent hardening work-hardening Bauschinger effect aluminium single crystal plastic deformation

Increased expression of the nitric oxide synthase gene and protein in corpus cavernosum by repeated dosing of udenafil in a rat model of chemical diabetogenesis

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2009年第4期11卷 435-442页

作者： GJ Ahn HK chung ch Lee KK Kang BO Ahn Research Laboratory Dong-A Pharmaceutical Company Kiheung Yongin Kyunggi 446-905 Korea

Erectile dysfunction （ED） is a major complication of diabetes mellitus （DM）. This study investigates the relationship between ED and the downregulation of constitutive nitric oxide synthase （cNOS） in the corpus cavernosum （CC） of diabetic rats. It also examines the effects of udenafil, a phosphodiesterase type 5 （PDE5） inhibitor, on ED and cNOS expression levels. After 16 weeks of daily oral treatment with udenafil in diabetic rats, the intracavernous pressure/mean arterial pressure （ICP/MAP） ratio was recorded to measure erectile function, and cNOS expression was measured using reverse transcriptase （RT）-PCR and immunoblots. Although the ICP/ MAP ratio and the expression levels of endothelial NOS （eNOS） and neuronal NOS （nNOS） in the CC were markedly decreased in diabetic rats, long-term udenafil treatment improved the erectile function and increased cNOS expression compared with diabetic controls. These findings suggest that ED in DM is closely related to decreased cNOS expression in the CC and that udenafil has the ability to compensate for this pathological change by modulating cNOS expression. Udenafil also has an inhibitory role in cyclic guanosine monophosphate （cGMP） degradation.

关键词： cNOS diabetes mellitus erectile dysfunction udenafil

Ac voltammetric and square wave voltammetric study of the self-assembled monolayers of thiol-functionalized viologen derivative

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

chinese Journal of chemistry 1997年第2期15卷 130-137页

作者： Li, JH Yang, ch Yan, JC chen, WQ Dong, SJ chINESE ACAD SCI CHANGCHUN INST APPL CHEMELECTROANALYT CHEM LABCHANGCHUN 130022JILINPEOPLES R CHINA

Electroactive self-assembled monolayers (SAMs) containing viologen group are formed through the adsorption of thiol-functionalized viologen compound ch3(ch2)(9)V2+(ch2)(8)SH, where V2+ is N,N'-dialkylbipyridinium (i.e. a viologen group), onto gold electrodes from methanol/water solution and its electrochemical behavior is investigated ty Ac voltammetry and square wave voltammetry, which have the high sensitivity against background charging. The viologen SAM formed is a sub-monolayer and the normal potentials corresponding to the two successive one-electron transfer processes of the active centers (viologen) are -360 mV and -750 mV (vs. Ag/AgCl) in 0.1 mol/L phosphate buffer solutions (pH 6.96) respectively, and the standard electron transfer rate constant is 9.0 s(-1). The electrochemical behavior of this SAM in various solutions has been preliminarily discussed.

关键词： self-assembled monolayers viologen Ac voltammetry square wave voltammetry

Systematic Study of Nanocrystalline Plasma Electrolytic Nitrocarburising of 316L Austenitic Stainless Steel for Corrosion Protection

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2007年第5期23卷 665-671页

作者： M.Aliofkhazraei P.Taheri A.Sabour Rouhaghdam ch.Dehghanian Materials Engineering Department Faculty of EngineeringTarbiat Modares UniversityTehranIran Materials Engineering Department Faculty of EngineeringTehran UniversityTehranIran

A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment （DOE） technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating processes factors. The experimental design consisted of four factors （Urea concentration, electrical conductivity of electrolyte, voltage and duration of process）, each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise （S/N） ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance （ANOVA）. The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.

关键词： Nanocrystalline plasma electrolytic nitrocarburising 316L austenitic stainlesssteel Corrosion resistance Potentiodynamic polarization Analysis of variance

Numerical Approach for Atmospheric Corrosion Monitoring Based on EIS of a Weathering Steel

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 261-271页

作者： ch.Thee Long Hao Jun-Hua Dong Xin Mu Wei Ke State Key Laboratory for Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences

Electrochemical impedance spectroscopy （EIS） and film thickness measurement have been employed to study the atmospheric corrosion of a weathering steel covered with a thin electrolyte layer in a simulated coastal-industrial atmosphere. The results indicate that the corrosion rate is a function of the covered electrolyte thickness and the wet/dry cycle. Within each wet/dry cycle, the increased corrosion rate is related to the increased Cl^- and SO4^2- concentration and an enhancement of oxygen diffusion rate with the evaporation of the electrolyte. In addition, the corrosion rate increases during the initial corrosion stage and then decreases as the wet/dry cycle proceeds. Moreover, one mathematical approach based on the numerical integration method to obtain corrosion mass loss of steel from the measurements of EIS has been developed, and this would be useful for the development of indoor simulated atmospheric corrosion tests.

关键词： Weathering steel Atmospheric corrosion Electrochemical impedance spectroscopy Steel rust Coastal-industrial atmosphere

Extraction of tectonic imprints using geospatial techniques:Evidence from Mandakini River basin,Uttarakhand,India

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第11期21卷 3720-3738页

作者： Atul Kumar PATIDAR Girish ch.KOTHYARI Manmohan KAUSHIK Sushil KHANDURI Department of Petroleum Engineering and Earth Sciences UPESDehradun 248007India KainGeotech Consultancy Dehradun 248007India

The existing literature discussed only the aerial aspect and provided a brief description of tectonic-geomorphic correlation with field *** present study we applied power law equations to estimate basin asymmetry factor(AF),Transverse topographic asymmetric factor(T),Hypsometric Integral(HI),longitudinal profile,stream length gradient index(SL),steepness index(Ksn),chi(χ),and knick point(Kp)analysis to examine the response of tectono-climatic fluctuations in the Mandakini River basin,central Uttarakhand *** decouple the causative tectono-climatic factors,we employed geospatial and Stream Power Incision Modeling(SPIM)*** is a globally accepted tool to predict an equilibrium state between fluvial erosion rates and the escalating function of stream *** is actively applied in modeling the transformation of river systems especially in rugged topographic *** present study covers SPIM-based morphometric assessment of the tectonically sensitive Mandakini River basin between Ramgarh Thrust(RT)and Vaikrita Thrust(VT)in the central region of Uttarakhand *** the upper reaches of the basin,U-shaped glaciated valleys dominate the landscape,while a rolling topography and deeply incised narrow valleys are depicted towards the ***,to understand the response of active tectonic over geomorphology,the drainage basin has been divided into two separate zones from the confluence point near the Rampur *** modeling outcomes indicate that the Mandakini drainage basin is in a disequilibrium state where channels are actively incising to ***,AF of 32 and 70 indicate leftward tilting in the upper reaches and rightward tilting in the lower reaches of the basin,*** HI value of 0.38 indicates a stage of maturity,characterized by a concave shape *** on the analysis it may be concluded that the fragile lithology and tectono-climatic fluctuations are dominantly controlling the topography and valle

关键词： Stream Power Incision Model(SPIM) Transverse Topographic Asymmetry Factor(T) Knick points Hypsometric curve Mandakini River Garhwal Himalaya

Simplistic hydrothermal synthesis approach for fabricating photoluminescent carbon dots and its potential application as an efficient sensor probe for toxic lead(II)ion detection

在线全文

学校读者我要写书评

暂无评论

Frontiers of chemical Science and Engineering 2023年第5期17卷 536-547页

作者： Trisita Ghosh Rajkumar Sahoo Suman Kumar Ghosh Pallab Banerji Narayan ch.Das Rubber Technology Centre Indian Institute of Technology KharagpurKharagpur 721302India Department of chemistry Indian Institute of Technology KharagpurKharagpur 721302India Materials Science Centre Indian Institute of Technology KharagpurKharagpur 721302India

The past decade has witnessed a variety of members of the carbon family along with exposure of carbon dots due to their magnificent properties in sensing,bioimaging,catalytic applications,biomedical fields,and so ***,we report the simple hydrothermal method to fabricate photoluminescent doped carbon quantum dots for the detection of noxious lead(II)***(II)ion is very venomous for both the environment and human health for which its detection is demanded area in the research *** as-prepared carbon dots show excellent photostability,low toxicity and significant photoluminescence properties along with good water *** with these properties,carbon dots have a quantum yield of approximately 15%.In the practical field of application,these carbon dots have been used as sensing probes for the detection of lead(II)ions with a detection limit of 60 nmol·L^(–1).The fluorescence intensity of carbon dots was remarkably quenched in the presence of the lead(II)ion selectively among all the tested metal ***,we have studied the Stern–Volmer relationship for lead(II)quenching along with the explanation of the probable quenching *** of the doped carbon dots in heavy metal ions sensing in an environmental sample was demonstrated.

关键词： carbon dots fluorescence heavy metal sensing practical application photoluminescence

Major bridge development in Hong Kong,china—past,present and future

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2011年第4期5卷 405-414页

作者： Michael ch HUI Doris YAU S15/F Civil Engineering and Development Building101Princess Margaret RoadHo Man TinKowloonHong KongChina

The first"modern"type of vehicular bridge was built in Hong Kong china in the *** need for an efficient transportation system to cope with population growth and enable economic development has demanded the construction of more and more bridges since the middle of the 20th *** 2007,Hong Kong had a total of about 1300 vehicular *** of these bridges,including the Tsing Ma Bridge,Kap Shui Mun Bridge,Ting Kau Bridge,and the cable-stayed bridge on the Hong Kong-Shenzhen Western Corridor,are considered to be major bridges supported by ***,the Stonecutters Bridge on Route No.8 is under construction and is expected to be completed in late *** the same time,the Hong Kong-Zhuhai-Macao Bridge will be in its detailed design stage *** efforts have been made by bridge builders to construct these giant structures,the upkeeping of these valuable assets at a high standard and ensuring their continuous functioning and performance during their intended lifespans will be another important task for bridge *** and structural health monitoring system(WASHMS)will play a key role in this respect.

关键词： Tsing Ma Bridge Kap Shui Mun Bridge Ting Kau Bridge Stonecutters Bridge Hong Kong-ZhuhaiMacao Bridge wind and structural health monitoring system(WASHMS)

Exploring COVID-19 from the perspectives of healthcare personnel in Malawi

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Health Care Science

Health Care Science 2023年第4期2卷 242-254页

作者： chúk Odenigbo Eric Crighton Department of Geography Environment and Geomatics at the University of Ottawa60 UniversityOttawaOntarioCanada

Background:The Coronavirus 2019 disease(COVID-19)brought many healthcare systems around the world to the point of collapse all the while putting the lives of healthcare workers at *** study forgoes an institutional look at healthcare to center individual healthcare personnel in Malawi to better understand(1)how the worldviews of healthcare workers impact their work in the context of COVID-19,(2)how COVID-19 impacted healthcare workers,and(3)the unique conditions faced by being a healthcare worker in a low-income ***:This research uses a hermeneutic phenomenological approach to qualitative methodology involving in-depth interviews(n=15)with health-care workers,traditional healers,and hospital *** data collected were inductively coded and analyzed using the framework method,producing rich descriptions on how COVID-19 impacted the lifeworlds of healthcare workers in ***:The findings reveal many of the struggles healthcare workers faced due to misaligned government policy and perceived proximity to COVID-19;outline their needs such as wanting better resources,funds,wages,and public health communication;and,exemplify the significant role that personal biases,worldviews,and sense of fear played in how healthcare workers perceived and interacted with ***:Much of what was said echoes beyond borders,reflecting common global sentiments felt by healthcare personnel,and offers directions to explore building policies,strategies,and plans in preparation for any future disease outbreaks.

关键词： COVID-19 pandemic healthcare workers fear Malawi discrimination violence