检索结果-南通市图书馆

On-farm Conservation of landraces of Rice (Oryza Sativa l.) through Cultivation in the kumaun Region of Indian Central himalaya

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2007年第4期4卷 354-360页

作者： R. k. Agnihotri l. M. S. Palni G. B. Pant Institute of himalayan Environment and Development Kosi - Katarmal Almora 263 643 Uttaranchal India State Biotechnology Programme government of Uttaranchal Biotech Bhavan P. O. Haldi U. S. Nagar 263 146 Uttaranchal India

The himalayan region is a known hot spot of crop diversity. Traditional varieties (usually called primitive cultivars or landraces), having withstood the rigors of time (including harsh climatic conditions as well as attacks of insects, pests and diseases), can still be found in crop fields in rural parts of Indian Central himalaya (ICh). These landraces harbor many desired traits from which, for example, varieties that are tolerant/resistant to abiotic/biotic stresses could be developed. In addition to the above benefits, landraces provide a basis for food security and a more varied and interesting diet. Some landraces are also known to be of medicinal value. These, along with some lesser known hill crops, are often referred to by different names such as under exploited crops, crops for marginal lands, poor person crops, and neglected mountain crops. The himalayan region continues to be a reservoir of a large number of landraces and cultivars whose economic and ecological potential is yet to be fully understood and/or exploited. Indians have had a history of rice cultivation since ancient times. Farmers, including tribals inhabiting the IhR, still cultivate a plethora of landraces of rice and thus directly contribute towardson-farm conservation of valuable germplasm and help in the preservation of crop diversity. The present paper looks at the on-farm conservation of rice germplasm, which is still practised in the kumaun region of ICh.

关键词： Germplasm himalaya landraces on-farm conservation rice

Transport of Nitrogen Assimilation in Xylem Vessels of Green Tea Plants Fed with Nh_4-N and NO_3-N

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2008年第2期18卷 222-226页

作者： k. Oh T. kATO h. l. XU Center for Environmental Science in Saitama Saitama 347-0115 （Japan） Jinenjou-no-kai NPO Shizuoka 421-0302 （Japan） International Nature Farming Research Center 5632 Hata Nagano 390-1401 （Japan）

An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-Nh4 were fed to the root of tea plants （Camellia sinensis l.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-Nh4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-Nh4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-Nh4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and Nh4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-Nh4.

关键词： amino acid 15^N nitrogen assimilation tea plant xylem sap

A unified framework for isotropic meshing based on narrowband Euclidean distance transformation

在线全文

学校读者我要写书评

暂无评论

Computational Visual Media 2015年第3期1卷 239-251页

作者： yuen-Shan leung Xiaoning Wang Ying he Yong-Jin liu Charlie C.l.Wang School of Computer Engineering Nanyang Technological University Department of Computer Science and Technology Tsinghua University Department of Mechanical and Automation Engineering The Chinese University of Hong Kong

In this paper, we propose a simpleyet-effective method for isotropic meshing relying on Euclidean distance transformation based centroidal Voronoi tessellation(CVT). Our approach improves the performance and robustness of computing CVT on curved domains while simultaneously providing highquality output meshes. While conventional extrinsic methods compute CVTs in the entire volume bounded by the input model, we restrict the computation to a 3D shell of user-controlled thickness. Taking voxels which contain surface samples as sites, we compute the exact Euclidean distance transform on the GPU. Our algorithm is parallel and memory-efficient,and can construct the shell space for resolutions up to 20483 at interactive speed. The 3D centroidal Voronoi tessellation and restricted Voronoi diagrams are also computed efficiently on the GPU. Since the shell space can bridge holes and gaps smaller than a certain tolerance, and tolerate non-manifold edges and degenerate triangles, our algorithm can handle models with such defects, which typically cause conventional remeshing methods to fail. Our method can process implicit surfaces, polyhedral surfaces, and point clouds in a unified framework. Computational results show that our GPU-based isotropic meshing algorithm produces results comparable to state-ofthe-art techniques, but is significantly faster than conventional CPU-based implementations.

关键词： centroidal Voronoi tessellation(CVT) Euclidean distance transformation GPU isotropic meshing polygonal meshes point clouds implicit surfaces

A new semi-quantitative Surface-Enhanced Raman Spectroscopy (SERS) method for detection of maleimide (2,5-pyrroledione) with potential application to astrobiology

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2021年第5期12卷 421-426页

作者： J.Aramendia l.Gomez-Nubla M.l.Tuite k.h.Williford k.Castro J.M.Madariaga Jet Propulsion laboratory California Institute of Technology4800 Oak Grove DrPasadenaCA 91109United States Department of Analytical Chemistry University of the Basque Country UPV/EHUP.O.Box 64448080 BilbaoSpain

Nitrogen-containing heterocyclic compounds are fundamental biochemical components of all life on Earth and,presumably,life elsewhere in our solar *** and characterization of these compounds by traditional solvent extraction,chromatographic separation,and GC-MS analysis require more sample mass than will be available from samples returned to Earth from *** its small sample mass requirement,Surface Enhanced Raman Spectroscopy could be an appropriate technique for analysis of returned *** have developed a SERS method for the detection of maleimide(2,5-pyrroledione),an N-containing heterocycle with a structure that is widespread in *** semi-quantitative methodology accurately determines maleimide concentration in the range from 60 mg/ml to 120 mg/*** present a maleimide SERS standard spectrum which will be useful as a reference for future *** present work demonstrates an easy,accurate,and effective method for the non-destructive qualitative and semi-quantitative study of maleimide as a first step toward developing a method for analysis of related compounds.

关键词： Maleimide Surface-Enhanced Raman Spectroscopy Astrobiology Biosignature Extraterrestrial life

INFlUENCE OF FIBER COATING ON TENSIlE BEhAVIOR OF UNIDIRECTIONAl C/Mg COMPOSITES

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 1997年第5期10卷 398-402页

作者： Zhang, k. Wang, Y.Q. Zhou, B.l. Zhou, Y.h. li, h.l. Inst of Metal Research Chinese Acad of Sciences Shenyang China

The mechanical properties and deformation mechanisms of unidirectional carbon fiber reinforced magnesium composites under tensile loading are studied. Two different materials are used as fiber coatings: a single silica and a gradient C/SiC/SiO[sb 2]. The results show that, under the same preparation conditions, composite with the former coating is broken in a non-cumulative mode and its failure stress is rather low. Conversely, the latter coating demonstrates much better efficiency and the corresponding composite is broken in a cumulative mode.

关键词： Metallic matrix composites Carbon fibers Tensile strength Elastic moduli Coatings Silica Deformation Crack propagation Crack initiation Fracture Stresses Strain

Universal properties of relaxation and diffusion in condensed matter

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第1期26卷 70-85页

作者： k l Ngai State key laboratory of Metastable Materials Science and Technology. Yanshan University Qinhuangdao 066004 China

By and large the research communities today are not fully aware of the remarkable universality in the dynamic properties of many-body relaxation/diffusion processes manifested in experiments and simulations on condensed matter with diverse chemical compositions and physical structures. I shall demonstrate the universality first from the dynamic processes in glass-forming systems. This is reinforced by strikingly similar properties of different processes in contrasting interacting systems all having nothing to do with glass transition. The examples given here include glass-forming systems of diverse chemical compositions and physical structures, conductivity relaxation of ionic conductors（liquid, glassy, and crystalline）,translation and orientation ordered phase of rigid molecule, and polymer chain dynamics. Universality is also found in the change of dynamics when dimension is reduced to nanometer size in widely different systems. The remarkable universality indicates that many-body relaxation/diffusion is governed by fundamental physics to be unveiled. One candidate is classical chaos on which the coupling model is based, Universal properties predicted by this model are in accord with diverse experiments and simulations.

关键词： many-body relaxation/diffusion universal dynamics coupling model classical chaos

Ophthalmology in the time of COVID-19: experience from hong kong Eye hospital

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2020年第6期13卷 851-859页

作者： Stephanie S.l.Cheung Cherie Y.k.Wong Jason C.k.Chan Carmen k.M.Chan N.M.lam hunter k.l.yuen Victoria W.Y.Wong Chi Wai Tsang Clement C.Y.Tham Department of Ophthalmology and Visual Sciences the Chinese University of Hong KongHong Kong SARChina hong kong Eye hospital Hong Kong SARChina

AIM:To review international guidelines and to share our infection control experience during the coronavirus disease 2019(COVID-19)pandemic at a tertiary eye centre in hong ***:Infection control guidelines and recommendations from international ophthalmological bodies are reviewed and *** measures at our hospital were drawn up as per international and local health authorities’guidelines and implemented with the collaboration of doctors,nurses and administrative ***:The aims of our infection control measures are to 1)minimize cross-infection within the hospital;2)protect and support hospital staff;3)ensure environmental *** minimize the risk of cross-infection,outpatient attendance and elective surgery have been reduced by 40%,and general anesthesia procedures were reduced by 90%.Patients entering the hospital are screened for fever,travel history,contact and cluster history,and COVID-19 related *** protect and support hospital staff,we ensure provision of adequate personal protective equipment(PPE)and provide clear guidelines on the level of PPE needed,depending on the clinical *** protective measures include provision of work uniforms,easy access to alcohol-based hand rub,opening new lunch areas,implementation of self-monitoring and self-reporting systems,and communication via online education and ***,environmental control is achieved by ensuring regular disinfection of the hospital premise,enhancing ventilation,and usage of disposable ophthalmic ***:Our multi-pronged approach to infection control is,so far,successful in minimizing infection risks,while allowing the maintenance of essential ophthalmic services.

关键词： COVID-19 coronavirus SARS-CoV-2 ophthalmology infection control hong kong

Relationship between the fatigue behavior and grain structures of an as-extruded Mg-6.2%Zn-0.6%Zr(in wt.%)alloy

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

Journal of Materials Science & Technology 2023年第18期149卷 119-126页

作者： B.J.Wang D.k.Xu C.l.Jiang l.Y.Sheng E.h.han School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang 110159China key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Binzhou Institute of Technology Binzhou 256606China Shandong key laboratory of Advanced Aluminium Materials and Technology Binzhou 256606China Shenzhen Institute Shenzhen Key Lab Human Tissue Regenerate&RepairPeking UniversityShenzhen 518057China

Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(Zk60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain *** them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the typical“bi-modal”grain structure had the lowest fatigue strength of 110 *** analysis demon-strated that for the fine grain structure,fatigue cracks preferentially nucleated at grain *** the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by the cracking along slip bands.

关键词： Mg alloys Grain structure Cyclic slips Fatigue behavior Crack initiation

P recision l ivestock F arming: A n international review of scientific and commercial aspects

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

International Journal of Agricultural and Biological Engineering 2012年第3期5卷 1-9页

作者： T M Banhazi h lehr J l Black h Crabtree P Schofield M Tscharke D Berckmans National Centre for Engineering in Agriculture University of Southern QueenslandToowoomba CampusQLDAustralia Syntesa(ltd.) BarcelonaSpain John l Black Consulting PO Box 4021Warrimoo NSWAustralia Farmex ltd Wyvols Court FarmBasingstoke RoadSwallowfieldReadingUK Silsoe livest ock Systems ltd Wrest ParkSilsoeBedsUK M3-BIORES Katholieke Universiteit LeuvenKasteelpark ArenbergLeuvenBelgium

Precision livestock Farming(PlF)is potentially one of the most powerful developments amongst a number of interesting new and upcoming technologies that have the potential to revolutionise the livestock farming *** properly implemented,PlF or Smart Farming could(1)improve or at least objectively document animal welfare on farms;(2)reduce greenhouse gas(GhG)emission and improve environmental performance of farms;(3)facilitate product segmentation and better marketing of livestock products;(4)reduce illegal trading of livestock products;and(5)improve the economic stability of rural ***,there are only a few examples of successful commercialisation of PlF technologies introduced by a small number of commercial companies which are actively involved in the PlF commercialisation *** ensure that the potential of PlF is taken to the industry,it is recommended to:(1)establish a new service industry;(2)verify,demonstrate and publicise the benefits of PlF;(3)better coordinate the efforts of different industry and academic organisations interested in the development and implementation of PlF technologies on farms;and(4)encourage the commercial sectors to assist with professionally managed product development.

关键词： Precision livestock Farming(PlF) smart farming commercialisation scientific issue animal welfare efficiency