检索结果-南通市图书馆

Soil moisture controls the spatio-temporal pattern of soil respiration under different land use systems in a semi-arid ecosystem of Delhi,India

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological Processes 2020年第1期9卷 172-184页

作者： Archana Meena M.Hanief J.Dinakaran k.S.Rao Department of Botany University of RajasthanJaipurRajasthan 302004India Department of Botany Baba Ghulam Ghulam Shah Badshah UniversityRajouriJammu and Kashmir 185234India Department of Botany Bhaskaracharya College of Applied SciencesUniversity of DelhiDwarkaDelhi 110007India Department of Botany University of DelhiDelhi 110007India

Background:Soil respiration(S_(R))is a critical process for understanding the impact of climatic conditions and land degradation on the carbon cycle in terrestrial *** measured the S_(R) and soil environmental factors over 1 year in four land uses with varying levels of disturbance and different vegetation types viz.,mixed forest cover(MFC),Prosopis juliflora(Sw.)forest cover(PFC),agricultural field(AF),and vegetable field(VF),in a semi-arid area of Delhi,*** primary aim was to assess the effects of soil moisture(S_(M)),soil temperature(S_(T)),and soil microbial activity(S_(MA))on the S_(R).Methods:The S_(R) was measured monthly using an LI-6400 with an infrared gas analyser and a soil *** S_(M) was measured using the gravimetric *** S_(T)(10 cm)was measured with a probe attached to the *** S_(MA) was determined by fluorescein diacetate ***:The S_(R) showed seasonal variations,with the mean annual S_(R) ranging from 3.22 to 5.78μmol m^(−2) s^(−1) and higher S_(R) rates of~15-55%in the cultivated fields(AF,VF)than in the forest sites(MFC,PFC).The VF had significantly higher S_(R)(Pk and non-significant in the PFC,MFC,and AF(R^(2)=0.14-0.31;P>0.05).Contrasting results were observed in the VF,which showed high S_(R) during summer(May;11.21μmol m^(−2) s^(−1))and a significant exponential relationship with the S_(T)(R^(2)=0.52;P<0.05).The S_(R) was positively related to the SMA(R2=0.44-0.5;P<0.001).The interactive equations based on the independent variables S_(M),S_(T),and S_(MA) explained 91-95

关键词： Soil respiration Soil moisture Soil microbes Soil temperature Precipitation Land use change Semi-arid ecosystems

Characterization of thixoforming process of 100Cr6 steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2010年第S3期20卷 916-920页

作者： k.P.SOLEk A.RASSILI J.C.PIERRET G.VANEETVELD AGH University of Science and Technology av.Mickiewicza 3030-059 KrakówPoland Thixo-Unit ULg PiMW(B56)University of L iègeBd de Colonster 4B-4000 LiègeBelgium

The main goal of this work is to analyze the semi-industrial process of steel *** process was carried out using industrial *** equipment consists of a heating device,industrial robots and a hydraulic *** globular microstructure ensuring thixotropic properties was obtained using the SIMA *** is one of the simplest and cheapest methods which could be easy applied in the case of steel *** this work,the hot forged rods,commercially produced from 100Cr6 steel,were *** first part of the work concerned the determination of the proper temperature range,for thixoforming of 100Cr6 ***,some heating tests were carried out in order to obtain as uniform temperature distribution as *** process was executed using inductive *** analysis of heated samples reveals globular particles surrounded by liquid *** last,the thixoforming process was carried out using closed-die forming *** filled die cavity and good microstructure of the part show that applied process parameters were properly selected.

关键词： thixoforming globular microstructure rheological properties physical modeling numerical modeling

Communication outcomes following cochlear implantation in a child with cystic cochleovestibular anomaly

在线全文

学校读者我要写书评

暂无评论

Journal of Otology 2016年第1期11卷 38-41页

作者： N.Banumathy Naresh k.Panda Department of ENT Post Graduate Institute of Medical Education and Research (PGIMER)

Cochlear implantation is one of the best amongst the various management options available for children and adults with severe to profound sensorineural hearing *** ear and internal auditory canal(IAC) malformations accounts to approximately 25% of congenital sensorineural hearing loss in *** primary goal of this report was to evaluate the communication outcomes after cochlear implantation in a child with cystic cochleovestibular anomaly(CCVA).The child was evaluated through various standardized outcome measures at regular intervals to track the progress in terms of auditory and spoken language *** scores on Categories of Auditory Perception(CAP),Meaningful Auditory Integration Scale(MAIS),Speech Intelligibility Rating(SIR),Meaningful Use of Speech Scale(MUSS),and listening and spoken language skills showed a significant leap in 12 months duration post *** report thus highlights and correlates the significant progress in auditory and spoken language skills of the child with congenital malformations to appropriate auditory rehabilitation and intensive parental training.

关键词： Cochlear implants Cystic cochleovestibular anomaly Inner ear malformation Communication outcomes

Deep learning for exploring ultra-thin ferroelectrics with highly improved sensitivity of piezoresponse force microscopy

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 2066-2073页

作者： Panithan Sriboriboon Huimin Qiao Owoong kwon Rama k.Vasudevan Stephen Jesse Yunseok kim School of Advanced Materials and Engineering Sungkyunkwan University(SKKU)SuwonRepublic of Korea Research Center for Advanced Materials Technology Core Research InstituteSuwonRepublic of Korea Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTNUSA

Hafnium oxide-based ferroelectrics have been extensively studied because of their existing ferroelectricity,even in ultra-thin film ***,studying the weak response from ultra-thin film requires improved measurement *** general,resonance-enhanced piezoresponse force microscopy(PFM)has been used to characterize ferroelectricity by fitting a simple harmonic oscillation model with the resonance ***,an iterative approach,such as traditional least squares(LS)fitting,is sensitive to noise and can result in the misunderstanding of weak *** this study,we developed the deep neural network(DNN)hybrid with deep denoising autoencoder(DDA)and principal component analysis(PCA)to extract resonance *** DDA/PCA-DNN improves the PFM sensitivity down to 0.3 pm,allowing measurement of weak piezoresponse with low excitation voltage in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2) thin *** hybrid approaches could provide more chances to explore the low piezoresponse of the ultra-thin ferroelectrics and could be applied to other microscopic techniques.

关键词： spectrum ferroelectric excitation

Exergy-energy analysis of full repowering of a steam power plant

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers in Energy 2015年第1期9卷 54-67页

作者： S. NIkBAkHT NASERABAD A. MEHRPANAHI M. R. ALIGOODARZ k. MOBINI Department of Mechanical Engineering Shahid Rajaee Teacher TrainingUniversity Tehran *** Iran

A 320 MW old steam power plant has been chosen for repowering in this paper. Considering the technical conditions and working life of the power plant, the full repowering method has been selected from different repowering methods. The power plant repower- ing has been analyzed for three different feed water flow rates： a flow rate equal to the flow rate at the condenser exit in the original plant when it works at nominal load, a flow rate at maximum load, and a flow rate when all the extractions are blocked. For each flow rates, two types of gas turbines have been examined： V94.2 and V94.3A. The effect of a duct burner has then been investigated in each of the above six cases. Steam is produced by a double- pressure heat recovery steam generator （HRSG） with reheat which obtains its required heat from the exhaust gases coming from the gas turbines. The results obtained from modeling and analyzing the energy-exergy of the original steam power plant and the repowered power plant indicate that the maximum efficiency of the repowered power plant is 52.04%. This maximum efficiency occurs when utilizing two V94.3A gas turbines without duct burner in the steam flow rate of the nominal load.

关键词： full repowering exergy analysis V94.2 andV94.3A gas turbines double-pressure HRSG duct burner,Bandarabbas steam power plant efficiency

CaMoO_4:Dy^(3+),k^+ near White Light Emitting Phosphor:Structural,Optical and Dielectric Properties

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2013年第7期29卷 633-638页

作者： S.k.Sharma S.Dutta S.Som P.S.Mandal Department of Applied Physics Indian School of MinesDhanbad 826004India

Undoped, Dy^3＋ doped and Dy^3＋, k^＋ codoped calcium molybdate phosphors have been synthesized by solid-state reaction method. X-ray diffraction studies reveal the tetragonal structure of the prepared phosphors having crystallite size 15-50 nm. Scanning electron microscopy （SEM） studies reveal the morphology and crystallite size of the prepared phosphors. Photoluminescence studies indicate that there are blue and yellow emissions at 489 and 576 nm, respectively corresponding to Dy^3＋ ion. The introduction of k＋ ion significantly influences the blue and yellow emissions which causes the near white light emission from this codoped phosphor. The intense absorption peak of the codoped phosphor at 210 nm is attributed to the band gap and a shoulder at 240 nm appears due to charge transfer from oxygen ions to neighbouring molybdenum ions. The band gap of the codoped phosphor is calculated as 5.5 eV from the absorption studies. The dielectric properties such as permittivity and dielectric loss are studied as a function of *** The authors are thankful to the Department of Science and Technology, New Delhi （Government of India） for funding this work under the Project SR/FTP/PS-087/2010.

关键词： X-ray diffraction Photoluminescence Absorption Dielectric

Relative preference of Lygus hesperus （Hemiptera： Miridae） to selected host plants in the field

在线全文

学校读者我要写书评

暂无评论

Insect Science 2010年第6期17卷 542-548页

作者： Apurba k. Barman Megha N. Parajulee Stanley C. Carroll Department of Entomology Texas A&M University College Station Texas AgriLife Research Center Lubbock Texas USA

Information on host plant preference of agriculturally important insect pests, such as Lygus hesperus （knight）, can be helpful in predicting its occurrence and future movement among crop and nonrop host plants. A field study was conducted during 2005 and 2006 to evaluate the host preference of Lygus to cotton and four other host plants in the Texas High Plains, including alfalfa （Medicago sativa L.）, wild sunflower （Helianthus annuus L.）, Russian thistle （Salsola iberica L.） and pigweed （Amaranthus palmeri L.）. Sampling for both nymphs and adults during 2005 （July to November） and 2006 （June to November） showed that alfalfa and Russian thistle were the two most preferred hosts out of the five hosts evaluated. Abundance of nymphs （numbers per 50 sweeps per host plant） during the sampling period also indicated the superior reproductive suitability of alfalfa and Russian thistle. Cotton appeared to be the least attractive host plant for Lygus when Russian thistle and alfalfa were available in the host mosaic. Seasonal abundance of Lygus was found to be lower during 2006 compared to 2005, which may be explained by the difference in rainfall patterns during these two years. In terms of species dominance, L. hesperus was the most dominant species in the sampled population followed by an inconsiderable fraction ofL. elisus and L. lineolaris.

关键词： cotton crop host-plant preference Lygus hesperus non-cotton crops

PROCESSING TECHNOLOGIES FOR TURBINE COMPONENTS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 453-456页

作者： G.k. Bouse(Howmet Corporation Technical Center, Whitehall, Michigan, USA ) Howmet Corp Technical Cent Whitehall United States

Processing technologies for the mass production of aero and industrial gas turbine engine hot-section components made by the investment casting process are discussed. Howmet Corporation is involved in most of these technologies because of the end-user's desire for a finished part. These technologies include pattern-making (using a variety of wax and plastic materials, rapid prototyping, 'hard' tooling, and wax injection machines), silica-zircon and alumina cores that produce internal passages, shells for very large parts and for use with alloys containing reactive elements, Ni, Co, and Ti alloys that are cleaner than ever before,zirconia, silica, and mullite crucibles;computer-controls,robotics,and the manufacture of vacuum casting furnaces; cleaning and finishing equipment designed to quickly process parts with minimal variation,and post-casting operations including hot isostatic pressing (HIP),heat treating,coating,and machining. These technologies will be discussed along with process capabilities required by today's turbine hot-section component suppliers.

关键词： investment casting rapid prototyping,vacuum induction melting(VIM),

Dual-Wavelength Passively Q-Switched Ytterbium-Doped Fiber Laser Based on Aluminum Oxide Nanoparticle Saturable Absorbers

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2017年第11期34卷 24-27页

作者： S.k.M.Al-Hayali S.Selleri A.H.Al-Janabi Institute of Laser for Postgraduate Studies University of Baghdad Department of Information Engineering Parma University

We report on generation of a dual-wavelength, all-fiber, passively Q-switched ytterbium-doped fiber laser using aluminum oxide nanoparticle （Al2O3-NP） thin film. A thin film of Al2O3 was prepared by embedding Al2O3-NPs into a polyvinyl alcohol （PVA） as a host polymer, and then inserted between two fiber ferrules to act as a saturable absorber （SA）. By incorporating the Al2O3-PVA SA into the laser cavity, a stable dual-wavelength pulse output centered at 1050 and 1060.7nm is observed at threshold pump power of 80mW. As the pump power is gradually increased from 80 to 300mW, the repetition rate of the generated pulse increases from 16.23 to 59 kHz, while the pulse width decreases from 19 to 6μs. To the best of our knowledge, this is the first demonstration for this type of SA operating in the 1 μm region.

关键词： SA Dual-Wavelength Passively Q-Switched Ytterbium-Doped Fiber Laser Based on Aluminum Oxide Nanoparticle Saturable Absorbers