检索结果-南通市图书馆

Large variability in ambient ozone sensitivity across 19 ethylenediurea-treated Chinese cultivars of soybean is driven by total ascorbate

引用

journal of Environmental sciences 2018年第2期30卷 10-22页

作者： Lijun jiang Zhaozhong Feng Lulu Dai Bo shang Elena Paoletti state Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China state Key Laboratory of soil and sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100049 China National Research Council Via Madonna del Piano 10 50019 Sesto Fiorentino Italy

The sensitivity of Chinese soybean cultivars to ambient ozone（O3） in the field is unknown,although soybean is a major staple food in China. Using ethylenediurea（EDU） as an O3 protectant, we tested the gas exchange, pigments, antioxidants and biomass of 19 cultivars exposed to 28 ppm·hr AOT40（accumulated O3 over an hourly concentration threshold of40 ppb） over the growing season at a field site in China. By comparing the average biomass with and without EDU, we estimated the cultivar-specific sensitivity to O3 and ranked the cultivars from very tolerant（〈 10% change） to highly sensitive（〉 45% change）, which helps in choosing the best-suited cultivars for local cultivation. Higher lipid peroxidation and activity of the ascorbate peroxidase enzyme were major responses to O3 damage, which eventually translated into lower biomass production. The constitutional level of total ascorbate in the leaves was the most important parameter explaining O3 sensitivity among these cultivars. surprisingly, the role of stomatal conductance was insignificant. These results will guide future breeding efforts towards more O3-tolerant cultivars in China, while strategies for implementing control measures of regional O3 pollution are being implemented. Overall, these results suggest that present ambient O3 pollution is a serious concern for soybean in China, which highlights the urgent need for policy-making actions to protect this critical staple food.

关键词： Ground-level ozone Glycine max Cultivar Ozone sensitivity Antioxidants Gas exchange Biomass Total ascorbate

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

sensitivity of digital elevation models:The scenario from two tropical mountain river basins of the Western Ghats,India

引用

Geoscience Frontiers 2014年第6期5卷 893-909页

作者： jobin Thomas sabu joseph K.P.Thrivikramji K.s.Arunkumar Inter University Centre for Geospatial Information science and Technology University of KeralaThiruvananthapuramKeralaIndia Department of Environmental sciences University of KeralaThiruvananthapuramKeralaIndia Department of Geology University of KeralaThiruvananthapuramKeralaIndia Department of Geology MES CollegePonnaniMalappuramKeralaIndia

The paper evaluates sensitivity of various spaceborne digital elevation models （DEMs）, viz., Advanced spaceborne Thermal Emission and Reflection Radiometer （AsTER）, shuttle Radar Topography Mapping Mission （sRTM） and Global Multi-resolution Terrain Elevation Data 2010 （GMTED）, in comparison with the DEM （TOPO） derived from contour data of 20 m interval of survey of India topographic sheets of 1 ： 50,000 scale. several topographic attributes, such as elevation （above mean sea level）, relative relief, slope, aspect, curvature, slope-length and -steepness （Ls） factor, terrain ruggedness index （TRI）, topo- graphic wetness index （TWI）, hypsometric integral （lhyp） and drainage network attributes （stream number and stream length） of two tropical mountain river basins, viz. Muthirapuzha River Basin and Pambar River Basin are compared to evaluate the variations. Though the basins are comparable in extent, they differ in respect of terrain characteristics and climate. The result.,; suggest that AsTER and sRTM provide equally reliable representation of topography portrayed by TOP（） and the topographic attributes extracted from the spaceborne DEMs are in agreement with those derived from TOPO. Despite the coarser resolution, sRTM shows relatively higher vertical accuracy （RMsE -- 23 and 20 m respectively in MRB and PRB） compared to AsTER （RMsE - 33 and 24 m） and GMTED （RMsE - 59 and 48 m）. Vertical accuracy of all the spaceborne DEMs is influenced by relief of the terrain as well as type of vegetation. Further, GMTED shows significant deviation for most of the attributes, indicating its inability for mountain-river-basin-scale studies.

关键词： DEM AsTER sRTM GMTEDTropical mountain river basins Western Ghats

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mg-based materials for hydrogen storage

引用

journal of Magnesium and Alloys 2021年第6期9卷 1837-1860页

作者： Yuanyuan shang Claudio Pistidda Gökhan Gizer Thomas Klassen Martin Dornheim Department of Materials Design Institute of Hydrogen TechnologyHelmholtz-Zentrum hereon GmbHMax-Planck-Straße 121502GeesthachtGermany Department of Mechanical Engineering Helmut-Schmidt-UniversityHolstenhofweg 8522043HamburgGermany

Over the last decade’s magnesium and magnesium based compounds have been intensively investigated as potential hydrogen storage as well as thermal energy storage materials due to their abundance and availability as well as their extraordinary high gravimetric and volumetric storage *** review work provides a broad overview of the most appealing systems and of their hydrogenation/dehydrogenation *** emphasis is placed on reviewing the efforts made by the scientific community in improving the material’s thermodynamic and kinetic properties while maintaining a high hydrogen storage capacity.

关键词： Hydrogen storage materials Magnesium-based hydrides Metal hydrides Nanostructures Catalysts Hydrogenation and dehydrogenation Kinetics Thermodynamics Activation energy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Environmental impact improvements due to introducing automation into underground copper mines

引用

International journal of Mining science and Technology 2021年第6期31卷 1159-1167页

作者： Kyle Moreau Corey Laamanen Ron Bose Helen shang john Ashley scott school of Engineering Laurentian UniversitySudburyON P3E 2C6Canada XPs–Glencore Greater SudburyON P0M 1S0Canada

A life-cycle assessment(LCA) model was developed to comparatively analyze the use of manual and automated mining equipment in underground copper mine *** and key variables that were determined to contribute to the environmental impact of operations were identified for six mine sites in a range of geographical locations around the *** model successfully calculated carbon dioxide(CO_(2) eq.) emissions to within 4.9% of the reported annual emissions from the site's respective *** implementation of automation was found to decrease global warming potential by a range of 11.4%-18.0% or 3.9-17.9 kg CO_(2) eq./t *** model was also used to estimate the average reductions across several impact potentials including,acidification(11.9%-17.8%),eutrophication(7.6%-13.7%),and human toxicity(16.0%-20.0%).World-wide the mining industry is moving toward introducing significantly more automation to enhance productivity and *** novel work demonstrates an important third dimension that can support this move,reduced environmental impact.

关键词： Automation Underground copper mines Environmental improvements Life cycle assessment Modelling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cystic fibrosis associated liver disease in children

引用

World journal of Hepatology 2021年第11期13卷 1727-1742页

作者： joseph j Valamparampil Girish L Gupte Liver Unit Birmingham Children’s HospitalBirmingham B46NHUnited Kingdom

Cystic fibrosis(CF)is an autosomal recessive disorder caused by mutations in the CF transmembrane conductance regulator *** liver disease develops in 5%-10%of patients with CF and is the third leading cause of death among patients with CF after pulmonary disease or lung transplant *** review the pathogenesis,clinical presentations,complications,diagnostic evaluation,effect of medical therapies especially CF transmembrane conductance regulator modulators and liver transplantation in CF associated liver disease.

关键词： Cystic fibrosis liver disease Portal hypertension Cirrhosis Liver transplantation Cystic fibrosis transmembrane conductance regulator modulators Distal intestinal obstructive syndrome

来源：

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

A flow chemiluminescence paper-based microfuidic device for detection of chromium(Ⅲ)in water

引用

journal of Innovative Optical Health sciences 2019年第6期12卷 56-71页

作者： Qiuping shang Peng Zhang Huijie Li Rui Liu Chunsun Zhang MOE Key Laboratory of Laser Life science&Institute of Laser Life science College of Biophotonics South China Normal University Guangzhou 510631P.R.China

In this work,a solely gravity and capillary force-driven flow chemiluminescence(GCF-CL)paper-based microfuidic device has been proved for the first time as a new platforn for inex-pensive,usable,mini mally instrumented dynamic chemiluninescence(CL)detection of chromium(Ⅲ)[Cr(Ⅲ)],where an appropriate angle of inclination between the loading and detection zones on the paper produces a rapid flow of CL prompt solution through the paper *** this study,we use a cost-effective paper device that is manufactured by a simple wax screen-printing method,while the signal generated from the Cr(Ⅲ)-catalyzed oxidation of luminol by H_(2)O_(2) is recorded by a low-cost and luggable CCD camera.A series of GCF-CL affecting factors have been evaluated *** optimal conditions,two linear relationships between GCF-CL intensities and the logarithms of Cr(Ⅲ)concentrations are obtained in the concentration mnges of 0.025-35 mg/L and 50-500 mg/L separately,with the detection limit of 0.0245mg/L for a les than 30s assay,and relative standard deviations(RsDs)of 38%,4.5%and 2.3%for 0.75,5 and 50 mg/L of Cr(Ⅲ)(n=8).The above results indicate that the GCF-CL paper-based microfluidic device possesses a receivable sensitivity,dynamic range,storage stability and ***,the developed GCF-CL is utilized for Cr(Ⅲ)detection in real water samples.

关键词： Paper-based microfuidics gravity flow cherniluminescence capillary flow wax screen-printing detection of chromium(Ⅲ)

来源：

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

Identification of aircraft longitudinal aerodynamic parameters using an online corrective test for wind tunnel virtual flight

引用

Chinese journal of Aeronautics 2024年第9期37卷 261-275页

作者： shang TAI Chen BU Yanling WANG Ting YUE Hailiang LIU Lixin WANG school of Aeronautical science and Engineering Beihang UniversityBeijing 100191China AVIC Aerodynamics Research Institute Harbin 150001China

The identification of aerodynamic parameters is accomplished through the test data of the dynamic movement of scaled aircraft models flying dynamically in wind tunnel,which can real-ize the accurate acquisition of the aerodynamic model of the aircraft in the preliminary stage for aircraft design,and it is of great significance for improving the efficiency of aircraft ***-ever,the translational motion of the test model in the wind tunnel virtual flight is subject to con-straints that result in distinct flight dynamics compared to free *** constraints have implications for the accuracy of aerodynamic derivatives obtained through the identification of wind tunnel test *** this issue in mind,the research studies the differences in longitudinal dynamic characteristics between unconstrained free flight and wind tunnel virtual flight,and inno-vatively proposes an online correction test based wind tunnel virtual flight test *** lon-gitudinal trajectory and velocity changes of the model are solved online by the aerodynamic forces measured during the test,and then the coupled relationship between aircraft translation and rota-tion is used to correct the model's pitch attitude motion *** the first time,the problem of solving the data approximation for free flight has been solved,eliminating the difference between the dynamics of wind tunnel virtual flight and free flight,and improving the accuracy of the aero-dynamic derivative identification *** experiment's findings show that accurate aerodynamic derivatives can be identified based on the online correction test data,and the observed behaviour of the identified motion model has similarities to that of the free flight motion model.

关键词： Wind tunnels Displacement constraints Online solution Flightcontrol law Aerodynamic parameter identification

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ground maneuver for front-wheel drive aircraft via deep reinforcement learning

引用

Chinese journal of Aeronautics 2021年第10期34卷 166-176页

作者： Hao ZHANG Zongxia jIAO Yaoxing shang Xiaochao LIU Pengyuan QI shuai WU school of Automation science and Electrical Engineering Bcihcmg UniversityBeijing 100083China Research Institute for Frontier science Beihang UniversityBeijing 1000H3China science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100083China Key Laboratory of Advanced Aircraft systems(Beihang University) Ministry of Industry and Information TechnologyBeijing 100083China Ningbo Institute of Technology Beihang UniversityNingbo 315800China The state Key Laboratory of Fluid Power and Mechatronic systems Zhejiang University.Hangzhou 310027China

The maneuvering time on the ground accounts for 10%–30%of their flight time,and it always exceeds 50%for short-haul aircraft when the ground traffic is *** also contribute significantly to emissions,fuel burn,and noise when taxiing on the ground at *** is an urgent need to reduce aircraft taxiing time on the ***,it is too expensive for airports and aircraft carriers to build and maintain more runways,and it is space-limited to tow the aircraft fast using *** drive capability is currently the best solution for aircraft,which can save the maneuver time for *** idea is proposed that the wheels are driven by APU-powered(auxiliary power unit)motors,APU is working on its efficient point;consequently,the emissions,fuel burn,and noise will be reduced *** Front-wheel drive aircraft,the front wheel must provide longitudinal force to tow the plane forward and lateral force to help the aircraft make a *** traction effects the aircraft’s maximum turning ability,which is difficult to be modeled to guide the controller *** reinforcement learning provides a powerful tool to help us design controllers for black-box models;however,the models of related works are always simplified,fixed,or not easily modified,but that is what we care about *** with complex models can the trained controller be ***-fidelity models that can easily modified are necessary for aircraft ground maneuver controller *** paper focuses on the maneuvering problem of front-wheel drive aircraft,a high-fidelity aircraft taxiing dynamic model is established,including the 6-DOF airframe,landing gears,and nonlinear tire force model.A deep reinforcement learning based controller was designed to improve the maneuver performance of front-wheel drive *** is proved that in some conditions,the DRL based controller outperformed conventional look-ahead controllers.

关键词： Front-wheel drive aircraft Ground maneuver Nose wheel steering Tire model Magic equation Deep reinforcement learning

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

刃宽对硬岩掘进影响的仿真及试验研究

引用

工程科学学报 2025年第1期47卷 13-24页

作者：尚勇孙靖东姜海峰许顺海段红磊孙朝阳北京科技大学机械工程学院北京100083 中铁工程装备集团隧道设备制造有限公司河南453000

滚刀在硬岩掘进中极易发生崩刃、偏磨等异常失效,研究硬岩掘进条件下刃型参数对滚刀破岩载荷和破岩效率的影响十分重要.本文采用滚刀破岩试验和仿真分析相结合的方法,从载荷曲线、破岩体积、破岩比能等方面分析了刃宽对滚刀破岩的影响.... 详细信息

滚刀在硬岩掘进中极易发生崩刃、偏磨等异常失效,研究硬岩掘进条件下刃型参数对滚刀破岩载荷和破岩效率的影响十分重要.本文采用滚刀破岩试验和仿真分析相结合的方法,从载荷曲线、破岩体积、破岩比能等方面分析了刃宽对滚刀破岩的影响.基于双线性本构模型及Benzeggagh–Kenane损伤断裂准则建立了岩石材料的内聚力本构模型,通过单轴抗压试验及巴西劈裂试验对内聚力本构模型的微观参数进行了校准,并进一步建立了滚刀破岩的内聚力仿真模型.结果表明:内聚力本构模型可以准确的模拟破岩过程中岩石裂纹的萌生和扩展过程.依据裂纹的萌生和扩展情况,滚刀破岩过程主要分为三个阶段:弹性阶段、裂纹萌生–扩展阶段及岩石破坏卸载阶段.滚刀破岩载荷和破岩体积随着贯入度、刀间距和刃宽的增加而增加;破岩比能随刃宽的增加呈先减小后增大的趋势.对于所选取的硬岩,采用13 mm刃宽滚刀破岩时比能最小,破岩效率最高;7 mm刃宽滚刀破岩时无法形成贯通岩片,相邻滚刀之间仍存在岩脊,破岩效率较低.

关键词：滚刀刃宽 Cohesive模型线切割试验破岩载荷破岩效率

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Upper Pleistocene human scapula from salawusu,Inner Mongolia,China

引用

Chinese science Bulletin 2006年第17期51卷 2110-2115页

作者： shang Hong LIU Wu WU Xinzhi DONG Guangrong Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044China Department of Anthropology Washington University St. Louis Missouri 63130 USA Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

This article presents a fossil human scapula which was found in situ from the lower part of the salawusu Formation in 1980 at the salawusu site of Inner Mongolia,China. The stratum is dated from 70.9±6.2 ka BP to 124.9±15.8 ka BP by TL method. Dates from 44±7 ka BP to 63±3 ka BP, 61―68 ka BP and 35.34±2 ka BP are obtained for the lower part of this layer by 230Th, IRsL and 14C respectively. Based on the comparisons between this scapula and the scapulae of Neanderthals, skhul/Qafzeh fossils, Eurasian Upper Paleolithic specimens and recent modern humans on the glenoid fossa, axillo-spinal angle, axillary border and other features, the present authors arrived at a preliminary conclusion that this salawusu scapula is characterized by modern fea- tures of Upper Pleistocene humans mixed with a Neanderthal-like feature.

关键词：更新世人类化石肩胛骨内蒙古

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：