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The Particle Time derivative of the Characteristic Geometric Quantities on Soft Curved Surface in Lagrangian description

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Acta Mechanica Solida Sinica 2018年第6期31卷 683-697页

作者： Yajun yin department of Engineering Mechanics School of Aerospace EngineeringTsinghua UniversityBeijing 100084China

This paper studies the particle time derivatives of the characteristic geometric quantities on soft curved surfaces in Lagrangian *** the basis of differential geometry, the calculation formulas for the particle time derivatives of the base vectors,metric tensor, Christoffel symbol,unit normal vector,curvature tensor and scalar curvatures on soft curved surface are *** limitations of particle time derivatives,*** non-covariance,are pointed *** research paves the way for studying particle time derivative of any tensor field on soft curved surface.

关键词： Soft curved surfaces Lagrangian description Characteristic geometric quantities Particle time derivative

Generalized covariant differentiation and axiom-based tensor analysis

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Applied Mathematics and Mechanics(English Edition) 2016年第3期37卷 379-394页

作者： Yajun yin department of Engineering Mechanics School of Aerospace EngineeringTsinghua University

This paper reports the new progresses in the axiomatization of tensor anal- ysis, including the thought of axiomatization, the concept of generalized components, the axiom of covariant form invariability, the axiomatized definition, the algebraic structure, the transformation group, and the simple calculation of generalized covariant differentia- tions. These progresses strengthen the tendency of the axiomatization of tensor analysis.

关键词： tensor analysis axiom of covariant form invariability generalized compo-nent generalized covariant differentiation covariant differential transformation group

A Hybrid Joining Technology for Aluminum/Zinc Coated Steels in Vehicles

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Journal of Materials Science & Technology 2010年第9期26卷 858-864页

作者： C.Y.Choi d.C.Kim d.G.Nam Y.d.Kim Y.d.Park School of Materials Science and Engineering Pusan National UniversityBusan Advanced Welding & Joining R&d division Institute of Industrial Technology Incheon dongnam Technology Service division Korea Institute of Industrial TechnologyBusan department of Advanced Materials Engineering Dong-Eui UniversityBusan

Currently,in the automotive industry,joining of the aluminum alloys with the steel is a crucial problem to be *** joining techniques including resistance spot and gas metal arc welding are not acceptable for those applications due to a number of metallurgical *** investigation was carried out to develop the hybrid joining process combining the resistance spot welding and *** this study,an attempt was made to apply hybrid process to the joining of dissimilar sheet metals,Al-Mg-Si（6000 series） alloy and low carbon steel *** process（resistance spot weld/brazing） using filler metal was found to be effective to overcome the incompatibility between aluminum alloy and *** hybrid joining process of Al alloy sheet and steel sheet did not produce acceptable bond strength,it was proved to have reasonable interfacial bond layer if the optimal process condition was applied.

关键词： Hybrid joining Aluminum alloy Steel Resistance welding Brazing

Advanced analytical determination of volatile organic compounds (VOC) and other major contaminants in water samples using GC-Ion Trap MS

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Journal of Environmental Sciences 2001年第1期13卷 25-36页

作者： B M Koroma K X Wang d d Jinya Laboratory of Socioeconomic Science of Food Production Nagoya University Japan.

The GC-Ion Trap MS is recently one of the most efficient instrumental analysis recommended for understanding the chemistry of volatile organic compounds, not only in water but even in the food chain and other environmental media (air and soil). Results of the experiment conducted on water samples from Kuguri and Yatsutani sampling stations showed considerably higher levels of organic enrichment (COd = 10 mg/L and 11 mg/L respectively). Total concentrations of Pb (0.072 mg/L and 0.093 mg/L) and Cd (0.004 mg/L and 0.011 mg/L) on the other hand, invariably exceeded the maximum allowable concentrations for human health and the living environment (Pb = 0.005 mg/L; Cd = 0.001 mg/L respectively). And the toxicity levels for these contaminants at LC50 showed critical impact on rainbow trout (hypersensitive species) at 0.14 mg/L for Pb and 0.007 mg/L for Cd in 96 hours respectively. Although these major contaminants including phenol and 3-, 4-cresol, showed relatively higher toxicity impact in the experimental media, it would remain contentious to justify any associated potential dangers without regular routine water monitoring, at least for a period of one year. Nevertheless, the data could serve as a benchmark through which other phenomena can easily be investigated.

关键词： www Advanced analytical determination of volatile organic compounds and other major contaminants in water samples using GC-Ion Trap MS VOC EB GC

Characteristics of urban ozone level in Hong kong

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Journal of Environmental Sciences 2001年第1期13卷 1-7页

作者： d.Y.C.LEUNG d.N.ZHANG department of Mechanical Engineering The University of Hong KongPokfulam RoadHong KongChina Research Institute of Environmental Engineering East China University of Science and TechnologyShanghai 200237China

The long term trend of ozone level in Hong Kong has been investigated. One of the characteristics of ozone level in Hong Kong is the existence of autumn maximum and summer minimum. Observations of the diurnal variation of ozone level have been made in different area categories. There are early morning peak and afternoon peak occurred in the diurnal variation, which are different from some metropolitans where only an afternoon peak is observed. A negative correlation coefficient was found between monthly ozone level with nitric oxide level. On the contrary, there is a positive correlation between ozone and nitrogen dioxide. The positive correlation coefficient between nitric oxide and nitrogen dioxide shows that the total amount of nitric oxide emitted from a series of moving and fixed sources greatly exceeded the stoichiometric amount of ozone formed from chemical reactions of precursors and long distance transportation.

关键词： ozone urban air pollution Hong kong China

Effectiveness of a fixed-depth sensor deployed from a buoy to estimate water-column cyanobacterial biomass depends on wind speed

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Journal of Environmental Sciences 2020年第7期32卷 23-29页

作者： Justin d.Chaffin douglas d.Kane Alex Johnson F.T Stone Laboratory and Ohio Sea Grant the Ohio State UniversityOH 43456USA division of Natural Science Applied Scienceand MathematicsDefiance CollegeDefiance OHF.T Stone LaboratoryThe Ohio State University and Ohio Sea GrantOH 43456USA

Water quality sondes have the advantage of containing multiple sensors,extended deployment times,high temporal resolution,and telecommunication with stakeholder accessible data ***,sondes that are part of buoy deployments often suffer from typically being fixed at one *** water treatment plants are interested in water quality at a depth of the water intake and other stakeholders(*** and swimmers)are interested in the surface,we examined whether a fixed depth of approximately 1 m could cause over-or under-estimation of cyanobacterial *** sampled the vertical distribution of cyanobacteria adjacent to a water quality sonde buoy in the western basin of Lake Erie during the summers of 2015–2017.A comparison of buoy cyanobacteria RFU(Relative Fluorescence Unit)at 1 m to cyanobacteria chlorophyll a(chla)measured throughout the water column showed occurrences when the buoy both under and overestimated the cyanobacteria chl a at specific *** differences between buoy measurements and at-depth grab samples occurred during low wind speeds(ds allowed cyanobacteria to accumulate at the surface above the buoy’s *** wind speeds(>4.5 m/sec)resulted in better agreement between the buoy and at-depth *** wind speeds 12 hr before sample collection decreased the difference between the buoy and at-depth samples for high wind speeds but not low *** suggest that sondes should be placed at a depth of interest for the appropriate stakeholder group or deploy sondes with the ability to sample at various depths.

关键词： Buoyancy Harmful algal bloom Lake Erie Microcystis Water quality

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农业拖拉机尾灯多色注塑模具设计

农机化研究 2025年第1期47卷 239-242,247页

作者：尹小定赵会娟江西机电职业技术学院机械工程学院南昌330013 济源职业技术学院机电工程系河南济源454650

以农业拖拉机尾灯为研究对象,分析了尾灯的内部结构和工艺性,并针对双色模具的特殊性,分析了模具成型方案和设计流程,基于AutoCAd和CAE软件完成了尾灯双色塑件模具的设计。开模试验表明:该产品符合设计需求,整个产品结构稳定,透明度好,... 详细信息

以农业拖拉机尾灯为研究对象,分析了尾灯的内部结构和工艺性,并针对双色模具的特殊性,分析了模具成型方案和设计流程,基于AutoCAd和CAE软件完成了尾灯双色塑件模具的设计。开模试验表明:该产品符合设计需求,整个产品结构稳定,透明度好,设计的模具结构合理、工艺流程可靠,能够满足实际的生产应用,工程应用价值较高。

关键词：农业拖拉机尾灯 CAd CAE 双色塑件模具

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Luminescence properties of Gd^(3+) containing glasses for ultra-violet(UV) light

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Journal of Rare Earths 2014年第5期32卷 389-393页

作者： d.d.Ramteke R.S.Gedam department of Applied Physics Visvesvaraya National Institute of Technology

Effect of Gd2O3 addition on optical properties of 27.5 Li2O-72.5 B2O3 glass systems was studied. density, differential thermal analysis （dTA）, optical absorption spectra and luminescence technique were used to characterize the prepared glasses. Emis- sion spectra showed two band 6p7/2→8S7/2 （311.5 nm） and 6p5/2→8S7/2 （305 nm） under the excitation of 274 nm. The intense emission at 311.5 nm suggested that these glasses could be useful as source of narrowband UV light.

关键词： glasses rare earths absorption band gap luminescence UV light

Electrical and optical properties of lithium borate glasses doped with Nd_2O_3

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Journal of Rare Earths 2012年第8期30卷 785-789页

作者： R.S. Gedam d.d. Ramteke department of Applied Physics Visvesvaraya National Institute of Technology

Glass series with general formula 25Li2O-（75-x）B2O3-xNd2O3 was prepared by conventional melt quench technique. Electrical and optical characterizations of these glasses were carried out. It was observed that conductivity of glasses decreased and activation energy in- creased with the addition of Nd2O3. The density and refractive index of the glasses increased while optical band gap and radiation length de- creased due to structural changes.

关键词： conductivity density refractive index optical absorption Tauc's plot rare earths