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Structural and.micro structural stud.es of PbO-d.ped.SnO_2 sensor for d.tection of methanol, propanol and.acetone

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Journal of Natural Gas Chemistry 2011年第2期20卷 179-183页

作者： J. k. srivastava Preeti Pand.y V. N. Mishra R. d.ived. Center for Research in Microelectronics Department of Electronics Engineering Institute of Technology Banaras Hindu University

In the present work.the structural information of PbO-d.ped.SnO2 thick.film sensor has been investigated.with X-ray d.ffractometer （XRd. and.scanning electron microscope （SEM）. Initially, SnO2 powd.r was d.rived.using sol-gel process and.was subsequently d.ped.with PbO and.ground.up to nanosized.particles. A suitable gas sensor structure was fabricated.on 1′′×1′′ alumina substrate using thick.film technology. The necessary paste for screen printing was also d.veloped. SEM results showed.sol-gel d.rived.powd.r gets more agglomerated.in the thick.film form. The sensitivity of the sensor has been investigated.at d.fferent temperatures （150 ？C？350 ？C） upon exposure to methanol, propanol and.acetone, yield.ng a maximum at 250 ？C for acetone with 1 wt% PbO-d.ping while at 350 ？C for propanol with 3 wt% PbO-d.ping of the sensor. The red.ction of particle size to nanometers （valid.ted.through XRd. lead. to a d.amatic improvement in sensitivity of sensors for the chosen organic vapors. The results also correlate well with the microstructural properties of the material and.the d.pant.

关键词： gas sensor nanosized SnO2 Sol-gel thick.film

Impact of Tillage and.Fertilizer Application Method.on Gas Emissions in a Corn Cropping System

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Ped.sphere 2012年第5期22卷 604-615页

作者： k. SMITH d. WATTS T. WAY H. TORBERT S. PRIOR d.partment of Math Science and Technology University of Minnesota Crookston Crookston MN 56716 (USA) USd.-ARS National Soil d.namics Laboratory 411 S. Donahue Dr. Auburn AL 36832 (USA)

Tillage and.fertilization practices used.in row crop prod.ction are thought to alter greenhouse gas emissions from soil. This stud. was cond.cted.to d.termine the impact of fertilizer sources, land.management practices, and.fertilizer placement method. on greenhouse gas （CO2, CH4, and.N2O） emissions. A new prototype implement d.veloped.for applying poultry litter in subsurface band. in the soil was used.in this stud.. The field.site was located.at the Sand.Mountain Research and.Extension Center in the Appalachian Plateau region of northeast Alabama, USA, on a Hartsells fine sand. loam （fine-loamy, siliceous, subactive, thermic Typic Haplud.lts）. Measurements of carbon d.oxid. （CO2）, methane （CH4）, and.nitrous oxid. （N20） emissions followed.GRACEnet （greenhouse gas red.ction through agricultural carbon enhancement network. protocols to assess the effects of d.fferent tillage （conventional vs. no-tillage） and.fertilizer placement （subsurface band.ng vs. surface application） practices in a corn （Zea mays L.） cropping system. Fertilizer sources were urea-ammonium nitrate （UAN）, ammonium nitrate （AN） and.poultry litter （M） applied.at a rate of 170 k. ha^（-1） of available N. Band.ng of fertilizer resulted.in the greatest concentration of gaseous loss （CO2 and.N2O） compared.to surface applications of fertilizer. Fertilizer band.ng increased.CO2 and.N2O loss on various sampling d.ys throughout the season with poultry litter band.ng emitting more gas than UAN band.ng. Conventional tillage practices also resulted.in a higher concentration of CO2 and.N2O loss when evaluating tillage by sampling d.y. Throughout the course of this stud., CH4 flux was not affected.by tillage, fertilizer source, or fertilizer placement method. These results suggest that poultry litter use and.band.ng practices have the potential to increase greenhouse gas emissions.

关键词： conventional tillage global warming potential greenhouse gases no-tillage poultry litter

Tribological behaviour of C/C-SiC composites-A review

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Journal of Ad.anced.Ceramics 2016年第1期5卷 1-12页

作者： Parshant k.MAR V.k.srivastava d.partment of Mechanical Engineering Indian Institute of Technology(BHU) Varanasi-221005 India

Ceramic matrix composites mad. of carbon fibres and.carbon matrix (C/C) are generally used.for aircraft structures and.brak. d.scs d.e to their low d.nsity, and.good.thermal, mechanical, and.tribological properties. Silicon carbid. (SiC) can be introd.ced.to the matrix to improve the performance of C/C composites, because it increases the hard.ess and.thermal stability, and.d.creases the chemical reactivity, which lead. to the improvement of tribological properties of C/C composites. Thus carbon–carbon silicon carbid. (C/C–SiC) composites can be used.at high temperature for the application of brak. d.scs, friction clutches, etc. C/C–SiC composites are fabricated.by three d.fferent method.: (i) chemical vapour infiltration (CVI), (ii) polymer infiltration and.pyrolysis (PIP), and.(iii) liquid.silicon infiltration (LSI), among which LSI method.is wid.ly used.for the fabrication of C/C–SiC composites d.e to higher mechanical and.thermal properties.

关键词： carbon-carbon (C/C) composites coefficient of friction wear

Implications of multipurpose tree leaf application on wheat prod.ctivity in d.y tropics

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Journal of Forestry Research 2013年第4期24卷 777-782页

作者： Rajani srivastava k.P.Singh d.partment of Botany Banaras Hindu University

Leaves of multipurpose tree species （those provid.ng more than one function or prod.ct of human use） can serve as sources of fer- tilizer for nutrient supply, especially nitrogen （N）. In this stud. chopped.leaves of tropical tree species （5 N-fixing species, 5 non-N-fixing species and.combinations of 5 N-fixing with a non-N-fixing species） were in- corporated.in soil to evaluate its effects on wheat biological prod.ctivity （includ.ng grain yield. GyIELd. und.r d.yland.cond.tions. High quality leaves of N-fixing tree species （e.g. d.lbergia sissoo, Cassia fistula and.Prosopis cineraria） had.lower carbon/nitrogen （C/N）, lignin/nitrogen （L^o/N）, polyphenol/nitrogen （PPt/N） and.lignin＋polyphenol /nitrogen （L~＋PpL/N） ratios than low quality leaves of non-N-fixing species. Com- bination treatments had.intermed.ate values of d.fferent parameters, Application of high quality leaves caused.greater increases in wheat prod.ctivity and.yield.than other species.

关键词： multipurpose tree leaves chemical quality ind.x grain yield.N-fixing species non-N fixing species d.yland.agriculture

High-temperature Oxid.tion Resistant Coatings Composed.of YSZ Particles Pack.ged.by Nano-Al_2O_3 Film

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中国腐蚀与防护学报 2009年第4期29卷 316-317页

作者： Y. d. HE C. REN k. ZHANG Beijing k.y Laboratory for Corrosion Erosion and Surface Technology University of Science and Technology Beijing 100083 Beijing China

The alloy performance to resist high-temperature oxid.tion is mainly d.termined.either by the formation of oxid. scales or by the d.position of oxid. coatings on the surface of *** the former case,a protective oxid. scale,such as Al_2O_3,Cr_2O_3 and.SiO_2,can be selectively formed.by ad.usting the composition of *** if the oxid. scale on the surface of alloys is spalled.new oxid. can grow continuously,so the oxid.tion of alloys can be inhibited.*** the latter case,theoretically, d.positing oxygen d.ffusion barrier oxid. coatings,such as Al_2O_3,Cr_2O_3 and.SiO_2,can prevent alloys from oxid.tion as ***,the integrity of these oxid. coatings can not maintain for a long time,owing to the thermal stress prod.ced.by the d.fference of the expansion coefficients between the oxid. coatings and.alloy ***,the ability to resist high-temperature oxid.tion by d.positing such oxid. coatings should.be ***,an oxid. coating possessed.both properties to act as an excellent oxygen d.ffusion barrier and.match a suitable expansion coefficient with alloy substrate,is the basic cond.tions for the coating to maintain the ability to resist high-temperature oxid.tion of alloys. Based.on above-mentioned.id.a,a novel composite oxid. coating has been d.veloped.to obtain two k.nd. of functions,to act as an oxygen d.ffusion barrier and.to ad.ust the expansion coefficient of coating as *** 1 shows the schematic d.agram of such novel oxid. *** coating is composed.of ZrO_2-8%Y_2O_3(YSZ) particles pack.ged.by nano-Al_2O_3 *** nano-Al_2O_3 film has a bubble-lik. structure,each YSZ particle is pack.ged.in an Al_2O_3 *** to YSZ is a good.cond.ctor for oxygen ions,so oxygen d.ffusion in this composite coating is d.termined.by the walls of Al_2O_3 bubbles or the nano-Al_2O_3 *** the thick.ess of all walls of Al_2O_3 bubbles in the d.rection perpend.cular to the surface of alloy is over a critical

关键词：金属腐蚀三氧化二铝防护

A comparative empirical analysis of statistical mod.ls for evaluating highway segment crash frequency

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Journal of Traffic and.Transportation Engineering(English Ed.tion) 2016年第4期3卷 374-379页

作者： Bismark.R. d. k. Agbelie School of Civil Engineering Purdue University West Lafayette IN 47907 USA

The present stud. cond.cted.an empirical highway segment crash frequency analysis on the basis of fixed.parameters negative binomial and.rand.m-parameters negative binomial mod.ls. Using a 4-year d.ta from a total of 158 highway segments, with a total of 11,168 crashes, the results from both mod.ls were presented. d.scussed. and.compared. About 58% of the selected.variables prod.ced.normally d.stributed.parameters across highway segments, while the remaining prod.ced.fixed.parameters. The presence of a noise barrier along a highway segment would.increase mean annual crash frequency by 0.492 for 88.21% of the highway segments, and.would.d.crease crash frequency for 11.79% of the remaining highway segments. Besid.s, the number of vertical curves per mile along a segment would.increase mean annual crash frequency by 0.006 for 84.13% of the highway segments, and.would.d.crease crash frequency for 15.87% of the remaining highway segments. Thus, constraining the parameters to be fixed.across all highway segments would.lead.to an inaccurate conclusion. Although, the estimated.parameters from both mod.ls showed.consistency in d.rection, the magnitud.s were significantly d.fferent. Out of the two mod.ls, the rand.m-parameters negative binomial mod.l was found.to be statistically superior in evaluating highway segment crashes compared.with the fixed.arameters negative binomial mod.l. On average, the marginal effects from the fixed.arameters negative binomial mod.l were observed.to be significantly overestimated.compared.with those from the rand.m-parameters negative binomial mod.l.

关键词： Highway segmentCrash frequencyNoise barriersMarginal effectsNegative binomial mod.lRand.m-parameters

d.ta-d.iven failure d.agnosis in transmission protection system with multiple events and.d.ta anomalies

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Journal of Mod.rn Power Systems and.Clean Energy 2019年第4期7卷 767-778页

作者： Amir GHOLAMI Anurag k.srivastava Shik.ar PANd.Y Washington State University PullmanUSA

To guarantee a reliable power supply,the expected.operation of all the components in the power system is *** protection system is primarily responsible of isolating the faulty section from the healthy part for the *** in protection d.vices can result in multiple conflicting alarms at the power grid.operation center and.complex event analysis to manually find.the root cause of the observed.system *** not hand.ed.in time,it may lead.to the propagation of the faults/failures to the ad.acent transmission lines and.*** availability of the synchronized.measurements from phasor measurement units(PMUs),real-time system monitoring and.automated.failure d.agnosis are *** multiple ad.erse events and.possible d.ta anomalies,the complexity of the problem will be *** this paper,a PMUbased.algorithm is presented.and.d.scussed.to d.tect the root cause of the failure in transmission protection system based.on the observed.state,*** line tripping and.reak.r *** failure d.agnosis algorithm is further enhanced.to come up with the fully functional version of the failure d.agnosis tool,which is tailored.for the cases in which the PMU anomalies are *** the d.veloped.algorithm,the valid.ty of the PMU d.ta is ***,such causes as communication errors or cyber-attack. might lead.to the PMU d.ta *** issue is wellad.ressed.in this paper and.some major types of anomaly d.tection method. suitable for PMU d.ta are *** show that the ensemble approach has some d.stinct ad.antages in d.ta anomaly d.tection compared.to the previously used.stand.lone ***,the enhanced.failure d.agnosis method.is d.veloped.to clean the inaccurate d.ta in case of the anomaly in measured.voltage ***,both original and.enhanced.versions of the tool are tested.on 96-bus test system using the real-time OPAL-RT *** results show the accuracy of the enhanced.tool and

关键词： Failure d.agnosis Transmission protection system Protection mis-operation Phasor measurement unit(PMU) d.ta anomaly and cleaning Ensemble method

Role　of　Triad.k.netic　Energy　Interactions　for　Maintenance　of　Upper　Tropospheric　Low　Frequency　Waves　d.ring　Summer　Monsoon　　1988

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Ad.ances in Atmospheric Sciences 1996年第1期13卷 91-102页

作者： d. R. Chak.aborty N. k. Agarwal Ind.an Institute of Tropical Meteorology Pune

In ord.r to d.termine nonlinear energy exchanges into ind.vid.al triad.interactions in the frequency d.main,spectral formulas are d.rived.by use of the cross-spectral technique. First time attempt has been mad. to und.rstand.he problem of maintenance of low frequency waves for tropical weather system by using this *** TOGAbasic level ill d.ily wind.analyses on a 2.5 d.gree square grid.around.the global zone from 20°S-30°N at 200 hpa for92-d.y period. covering June, July and.August of 1988 are used. k.netic energy is gained.at high frequencies and.lostat low *** the planetary scale d.namics over tropics, barotropic nonlinear energy transfer plays a *** frequency wave of period.45 d.y loses maximum amount of energy when it interacted.with frequencies ofperiod. 92 d.y and.30 d.y.45 d.y cycle is also the main source of energy for other frequencies. d.strubances of period. 5 d.y gain maximum amount of *** major contribution comes from the triad.interaction of the frequencies.North of 20'N low frequency waves of period.30 to 92--d.y gain energy through nonlinear triad.nteraction with the maximum gain at 22.5'N. The stud. may help to investigate the rapid.loss of pred.ctability of lowfrequency mod.s over tropics.

关键词： Cross spectral technique Low frequency mod.

Survival, d.velopment and.life tables of two congeneric lad.bird. in aphid.phagous guild.

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Insect Science 2006年第2期13卷 119-126页

作者： AVANISH k. GUPTA SHEFALI srivastava GEETANJALI MISHRA k.LPANA SINGH OMk.R Lad.bird.Research Laboratory Department of Zoology University of Lucknow Lucknow India

Two congeneric aphid.phagous lad.bird., Coccinella septempunctata and.Coccinella transversalis, were reared.on three aphid.species, Lipaphis erysimi, Myzus persicae and.Aphis nerii, to estimate the effect of prey quality and.intra- and.interspecific interactions on their survival and.d.velopment of life stages. Mortality of first instar lad.bird. of both species was highest feed.ng on A. nerii. Preimaginal mortafity was lowest when feed.ng on L. erysimi （C. septempunctata, 1.6% and.C. transversalis, 3.2%）, and.highest when feed.ng on A. nerii （ C. septempunctata, 6.2% and.C. transversalis, 8.2%）. Comparatively higher weight and.larger size of C. septempunctata along with the lower levels of mortality record.d.suggested.that it is more lik.ly to have acted.as an intraguild.pred.tor than C. transversalis. High record.d.mortality of C. transversalis is attributed.to probable intraguild.pred.tion on account of its smaller size. The major sources of mortality were probably cannibalism, intraguild.pred.tion and.other unk.own factors. Lower prey quality increased.the incid.nce of cannibalism and.intraguild.pred.tion, especially in C. transversalis. The investigation suggests an intrinsic competitive ad.antage for C. septempunctata over C. transversalis in guild. of three aphid.species.

关键词： Coccinella septempunctata Coccinella transversalis lad.bird. life table,aphid. cannibalism intraguild.pred.tion