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Chinese Annals of Mathematics,Series B 2000年第4期21卷 413-440页

作者： d. Kong department of Applied Mathematics Shanghai Jiaotong University Shanghai 200030 China

The author considers the life-span of classical solutions to Cauchy problem for general first order quasilinear strictly hyperbolic systems in two independent variables with "slow" decay initial data. By constructing an example, first it is illustrated that the classical solution to this kind of Cauchy problem may blow up in a finite time, even if the system is weakly linearly degenerate. Then some lower bounds of the life-span of classical solutions are given in the case that the system is weakly linearly degenerate. These estimates imply that, when the system is weakly linearly degenerate, the classical solution exists almost globally in time. Finally, it is proved that Theorems 1.1-1.3 in [2] are still valid for this kind of initial data.

关键词： Quasilinear strictly hyperbolic system Weak linear degeneracy Cauchy problem Classical solution Life-span

Quality assessment and hydrogeochemical characteristics of groundwater in Agastheeswaram taluk, Kanyakumari district, Tamil Nadu, India

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Chinese Journal Of Geochemistry 2014年第3期33卷 221-235页

作者： Srinivas Y Hudson Oliver d Stanley raj A Chandrasekar N Centre for GeoTechnology Manonmaniam Sundaranar University Vel Tech dr. rr & dr. Sr Technical University Avadi Chennai

The present study investigates the hydrogeochemical characteristics of groundwater quality in Agastheeswaram taluk of Kanyakumari district, Tamil Nadu, India. A total of 69 groundwater samples were collected during pre- and post-monsoon periods of 2011–2012. The groundwater quality assessment has been carried out by evaluating the physicochemical parameters such as pH, EC, TdS, HCO3-, Cl-, SO42-, Ca2+, Mg2+, Na+ and K+ for both the seasons. Based on these parameters, groundwater has been assessed in favor of its suitability for drinking and irrigation purpose. dominant cations for both the seasons are in the order of Na+ > Ca2+ > Mg2+ > K+ while the dominant anions for post monsoon and pre monsoon have the trends of Cl- > HCO3- > SO42- and HCO3- > Cl- > SO42-, respectively. Analytical results observed from various indices reveal that the groundwater quality is fairly good in some places. Analytical results of few samples show that they are severely polluted and incidentally found to be near the coasts, estuaries and salt pans in the study area. The Gibbs plot indicates that the majority of groundwater samples fall in rock dominant region, which indicates rock water interaction in the study area. The United States salinity(USSL) diagram shows that the groundwater is free from sodium hazards but the salinity hazard varies from low to very high throughout the study area. This reveals that the groundwater is moderately suitable for agricultural activities. The observed chemical variations in pre-monsoon and post-monsoon seasons may be the effect to rock-water interactions, ion-exchange reactions, and runoff of fertilizers from the surrounding agricultural lands.

关键词：地下水质量评价地下水水质水文特性马里印度水岩相互作用物理化学参数研究区域

Experimental investigation of tool wear and chip formation in cryogenic machining of titanium alloys

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Advances in Manufacturing 2015年第4期3卷 292-299页

作者： d. Biermann H. Abrahams M. Metzger Institute of Machining Technology TU Dortmund University Baroper StraBe 303 44227 Dortmund Germany

Titanium alloys are one of the most important design materials for the aircraft industry. The high strength-to-density-ratio and the compatibility with carbon fibre reinforced plastic are the reasons for a raising application in this field. The outstanding properties lead to challenging machining processes. High strength and low heat conductivity affect high mechanical and thermal loads for the cutting edge. Thus, the machining process is characterized by a rapid development of tool wear even at low cutting parameter. To reach a sufficient productivity it is necessary to dissipate the resulting heat from the cutting edge by a coolant. Therefore the cryogenic machining of two different titanium alloys is investigated in this work. The results point out the different behavior of the machining processes under cryogenic conditions because of the reduced thermal load for the cutting tool. According to this investigation, the cryogenic cooling with COa enables an increase of the tool life in comparison to emulsion based cooling principles when machining the α＋β-titanium alloy Ti-6Al-4V. The machining process of the high strength titanium alloy Ti-6Al-2Sn-4Zr-6Mo requires an additional lubrication realized by a minimum quantity lubrication （MQL） with oil. This combined cool- ing leads to a smoother chip underside and to slender shear bands between the different chip segments.

关键词： Titanium alloys . Cryogenic cooling Machining . Tool wear - Chip formation

Emerging carbon-based nanosensor devices:structures,functions and applications

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Advances in Manufacturing 2015年第1期3卷 63-72页

作者： S.Manzetti d.Vasilache F.Enrichi Fjordforsk A.S. Institute for Science and Technology6894 VangsnesNorway Science of Life Laboratory Department of Cell and Molecular BiologyUppsala University75124 UppsalaSweden Laboratory of Micromachined Structures Microwave Circuits and Devices-L4National Institute for Research and Development in Microtechnologies(IMT Bucharest)023573 BucharestRomania Laboratory for Nanofabrication of Nanodevices Veneto NanotechCorso Stati Uniti 435127 PadovaItaly

Bionanosensors and nanosensors have been devised in recent years with the use of various materials including carbon-based nanomaterials, for applications in diagnostics, environmental science and microelectronics. Carbon-based materials are critical for sensing applications, as they have physical and electronic properties which facilitate the detection of substances in solutions, gaseous compounds and pollutants through their conductive prop- erties and resonance-frequency transmission capacities. In this review, a series of recent studies of carbon nanotubes （CNTs） based nanosensors and optical systems are repor- ted, with emphasis on biochemical, chemical and envi- ronmental detection. This study also encompasses a background and description of the various properties of the nanomaterials, and the operation mechanism of the man- ufactured nanosensors. The use of computational chemistry is applied in describing the electronic properties and molecular events of the included nanomaterials during operation. This review shows that resonance-based sensing technologies reach detection limits for gases, such as ammonia down to 10-24 level. The study also shows that the properties of the carbon nanomaterials give them unique features that are critical for designing new sensors based on electrocatalysis and other reactive detection mechanisms. Several research fields can benefit from the described emerging technologies, such as areas of research in environmental monitoring, rapid-on site diagnostics, in situ analyses, and blood and urine sampling in medical and sport industry. Carbon nanomaterials are critical for the operational sensitivity of nanosensors. Considering the low cost of fabrication, carbon nanomaterials can represent an essential step in the manufacturing of tomorrow＇s commercial sensors.

关键词： Nanomaterials.Carbon-based.Graphene .Nanotubes. Sensors.detectors - Quantum mechanics

A compact charge-based model to study the nanoscale undoped double gate MOSFETs for nanoelectronic circuit design using genetic algorithms

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Journal of Semiconductors 2013年第4期34卷 30-36页

作者： T.Bendib F.djeffal d.Arar LEA Department of ElectronicsUniversity of Batna05000Algeria

The analytical modeling of nanoscale devices is an important area of computer-aided design for fast and accurate nanoelectronic design and optimization. In the present paper, a new approach for modeling semicon- ductor devices, nanoscale double gate dG MOSFETs, by use of the gradual channel approximation （GC） approach and genetic algorithm optimization technique （GA） is presented. The proposed approach combines the universal optimization and fitting capability of GA and the cost-effective optimization concept of quantum correction, to achieve reliable, accurate and simple compact models for nanoelectronic circuit simulations. Our compact models give good predictions of the quantum capacitance, threshold voltage shift, quantum inversion charge density and drain current. These models have been verified with 2d self-consistent results from numerical calculations of the coupled Poisson-Schrrdinger equations. The developed models can also be incorporated into nanoelectronic cir- cuit simulators to study the nanoscale CMOS-based devices without impact on the computational time and data storage.

关键词： nanoscale quantum genetic algorithm analytical model

Sulphur Mustard Induced Oxidative Stress and Its Prevention by Sodium 2, 3-dimercapto Propane Sulphonic Acid (dMPS) in Mice

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Biomedical and Environmental Sciences 2000年第3期13卷 225-232页

作者： S．C．PANT r.VIJAYArAGHAVAN 等 divisionofPharmacologyandToxicology DefenceResearchandDevelopmentEstablishmentJhansiRoadGwalior－474002India divisionofPharmacologyandToxicology DefenceResearchandDevelopmentEstabl

Sulphur mustard [bis(2 chloro ethyl) sulfide] (SM), a bifunctional alkylating agent has been frequently used as a chemical warfare agent. In the present study, the effects of sodium 2 3 dimercaptopropane sulphonic acid (dMPS) on some biochemical and histological parameters in mice, exposed to 1/4LC 50 concentration of SM vapor (10.5 mg/m\+3) were examined over a period of seven days. Exposure of SM resulted in a significant loss of blood, hepatic and pulmonary glutathione (GSH) and an elevation of hepatic and pulmonary oxidized glutathione (GSSG). These biochemical changes were accompanied by a number of histopathological alterations. The most prominent was congestion and degeneration in viscera and obliteration of chromatin material. These biochemical and histopathological changes were less marked in animals pre administered with dMPS followed by dMPS exposure indicating some protective value of the thiol (dMPS) against SM induced oxidative injury in mice.

关键词： Animals Female Mice Mustard Gas Oxidative Stress Unithiol

THE rOLE OF NIOBIUM IN NICKEL-BASEd SUPErALLOYS ANd CHArACTErIZATION OF PM ALLOY EP741NP

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 468-478页

作者： T. Carneiro J. radavich d. Furrer reference Metals Co. Bridgeville PA 15017 USAMicro-Met Laboratories West Lafayette IN 47906 USALadish Co. Inc. Cudahy WI 53110 USA

The role of niobium in nickel-based superalloys is reviewed. The importance of niobium as a strengthener is discussed. New developments in nickel-based superalloys are also briefly mentioned, including some results that show improved resistance to sulfidation by niobium. research results from a current program on the role of niobium in the russian powder metallurgy alloy EP741NP are presented. Future research plans on the role of niobium in superalloys are also discussed.

关键词： niobium superalloy alloy EP741NP powder metallurgy superalloy,nickel-based superalloy disk material

development and implementation of a validation protocol for crisis maps: reliability and consistency assessment of burnt area maps

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International Journal of digital Earth 2011年第S01期4卷 8-24页

作者： C.Corbane d.Carrion M.Broglia European Commission Joint Research CentreIspraItaly

Validation is an emerging topic in the field of geospatial information for emergency *** the framework of the Global Monitoring for Environment and Security initiative,the Services and Applications for Emergency response project seeks to implement and validate the pre-operational version of Emergency response Core *** that context,a dedicated effort has been made in the development and implementation of a comprehensive,productoriented validation protocol tailored to crisis maps and data *** paper presents the approach for validation of crisis maps and its application in the context of rapid mapping of forest fires in Corsica during the summer of *** also discusses the main challenges and the critical aspects of validation of geospatial information in emergency response services.

关键词： validation protocol crisis mapping remote sensing forest fires

Fabrication of Superhydrophobic Surfaces on Aluminum Alloy Via Electrodeposition of Copper Followed by Electrochemical Modification

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Nano-Micro Letters 2011年第3期3卷 160-165页

作者： Ying Huang d.K.Sarkar X-Grant Chen University research Center on Aluminum (CUrAL) University of Qubec at Chicoutimi

Superhydrophobic aluminum surfaces have been prepared by means of electrodeposition of copper on aluminum surfaces, followed by electrochemical modification using stearic acid organic molecules. Scanning electron microscopy(SEM) images show that the electrodeposited copper films follow "island growth mode" in the form of microdots and their number densities increase with the rise of the negative deposition potentials. At an electrodeposition potential of-0.2 V the number density of the copper microdots are found to be 4.5×104cm^(-2)that are increased to 2.9×105cm^(-2)at a potential of-0.8 V. Systematically, the distances between the microdots are found to be reduced from 26.6 μm to 11.03 μm with the increase of negative electrochemical potential from-0.2 V to-0.8 V. X-ray diffraction(Xrd) analyses have confirmed the formation of copper stearate on the stearic acid modified copper films. The roughness of the stearic acid modified electrodeposited copper films is found to increase with the increase in the density of the copper microdots. A critical copper deposition potential of-0.6 V in conjunction with the stearic acid modification provides a surface roughness of 6.2 μm with a water contact angle of 157?, resulting in superhydrophobic properties on the aluminum substrates.

关键词： Superhydrophobic aluminum surface Water contact angle Copper microdots Surface roughness Electrochemical modification

Evaluation of alternative conceptual models for groundwater modelling

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Geoscience Frontiers 2017年第3期8卷 437-443页

作者： Yangxiao Zhou H.M.P.S.d.Herath UNESCO-IHE Institute for Water Education

This study evaluates the alternative conceptual models for groundwater modelling. A true model was created with a synthetic alluvial fan-plain hydrogeological framework. Various alternative conceptual models were evaluated for groundwater flow simulations. The first alternative model is a single aquifer layer model; the second alternative model is a 3-layer aquifer model; and the third model is a B-layer model consisting of 3 aquifers separated by 2 aquitards. All models could fit very well to the observa- tions with optimized values of hydraulic conductivities. However, the single aquifer layer model can only compute water balance components with good accuracy. The 3-layer aquifer model can be used for water balance computation and groundwater head simulation with small errors. The 5-layer model is capable of simulating water budget, groundwater head distribution and travel times with high accuracy. Multi- model analysis found only the 3rd alternative model superior.

关键词： Alternative conceptual modelsMulti-model analysisWater budgetTravel time