检索结果-南通市图书馆

snow

引用

初中生 2006年第Z2期 66-67页

作者：龚欣怡湖南师大附中初0304班

伴随着骤然变冷的天气和这场小雪,我清楚地看到,自己热爱而又讨厌的冬天来了。我原来生活的那个南方城市没有雪,冬天女生甚至可以穿短裙。我不喜欢这样的城市,我要的是四季分明,不是四季如夏;要的是寒冬,不是暖冬。

关键词：羊绒 snow 雪花

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

snow

引用

疯狂英语（初中天地） 2006年第4期 66-66页

作者： Colfax Burgoyne Harman

关键词： snow

来源：

维普期刊数据库

同方期刊数据库

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

snow

引用

小雪花（小学快乐作文） 2004年第4期 45-45页

作者：李冬梅

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

snow

引用

China's Foreign Trade 2008年第1期 54-54页

作者： S.M.Riggin

Gently falling,floating down over me and you, standing here standing there the snow is falling. White flakes come down from heaven above, coming down like angels the snow is falling. All the fun times we've had outsid... 详细信息

关键词： down snow

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

snow damages on trees of an uneven age in mixed broadleaf forests:effects of topographical conditions and tree characteristics

引用

Journal of Forestry Research 2019年第4期30卷 1383-1394页

作者： Farzam Tavankar Angela Lo Monaco Mehrdad Nikooy Rachele Venanzi Amireslam Bonyad Rodolfo Picchio Department of Forestry Khalkhal BranchIslamic Azad UniversityKhalkhalIran Department of Agriculture and Forest Sciences(DAFNE) Tuscia UniversityVia S.Camillo de Lellis01100 ViterboItaly Department of Forestry Faculty of Natural ResourcesUniversity of GuilanSomehsaraIran

snow damage on natural stands is an important problem concerning mountainous forest *** the present research,the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees,stand and topography were studied in mountainous forests of northern Iran.A systematic sampling design was applied to the study area(140 ha),with 122 circular *** grid dimension was100 m and each plot area was 1000 m^*** four types of snow damage to trees include:crown damage(8.6%),stem breakage(5.4%),uprooting(3.2%),and bending(1.4%).The frequency of crown damage grew with an increase inthe diameter at breast height(DBH),while the frequency of stem breakage,uprooting and bending decreased with an increase the *** frequency of crown damage,stem breakage,and total damages was related to tree species(psnow *** amount of damage grew with increasing elevation and slope angle and decreased with increasing soil *** trees(DBHsnow damage than other *** damage decreased by as the trees in the stand became more mixed in *** susceptibility of trees to snow damage increased by height and slenderness *** adequate silvicultural operation,snow damage can be reduced to a minimum level in these natural forests.

关键词： Mixed forest Slenderness coefficient snow damage Stem breakage Uprooting

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

Synthesis of waterborne polyurethane using snow as dispersant:Structures and properties controlled by polyols utilization

引用

Journal of Materials Science & Technology 2019年第7期35卷 1491-1498页

作者： Changqing Fang Shaofei Pan Zhen Wang Xing Zhou Wanqing Lei Youliang Cheng Faculty of Printing Packaging Engineering and Digital Media TechnologyXi'an University of TechnologyXi'an710048China School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an710048China

waterborne polyurethane (WPU) dispersions have gained attention towards environm entally-friendly synthesis. In this article, a series of waterborne polyurethane em ulsions was successfully synthesized and extensively characterized in terms of thermal, mechanical properties, hydrophilic behavior and morphology. snowwas chosen as dispersant instead of comm only used water. Preparation param eters such as intrinsic properties and molecular weight of polyols were discussed systematically. A chain structure was confirmed by Fourier transform infrared (FT-IR) spectroscopy. when com paring the nature of the polyols (PPG, PEG and PNA, 2000g/mol) of this study, as-synthesized polyether waterborne polyurethane provided higher solid content, viscosity and water-resistance. However, polyester waterborne polyurethane perform ed differently and it exhibited higher therm al stability and crystallinity. When com paring the samples (WPU-N210, WPU-N220, WPU-N230 and WPU-N240) with different molecular weight of the same polyol (PPG) used as soft segment, the emulsion WPU-N220 with molecular weight of 2000g/mol PPG provided the highest solid content and lowest viscosity. It was observed th at particle size was uniform and highly dispersed for all sam ples from TEM images. Therm ogravim etric, differential scanning calorim etry (DSC) and X-ray diffraction results dem onstrated that the emulsion WPU-N230 with m olecular weight of 3000 g/mol PPG possessed higher therm al stability and crystallinity than the other samples. The reason was that the Tg and thermal stability were increased with increasing molecular weight. when molecular weight increased, the arrangem ent of soft segm ent became more regular and so did the regularity of the molecular chains. This work demonstrated that different polyols as soft segment applied could lead to great differences in the structure and property of the resulting WPU.

关键词： Waterborne polyurethane (WPU) snow Soft segment Polyester Polyether

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

snow cover estimation from MODIS and Sentinel-1 SAR data using machine learning algorithms in the western part of the Tianshan Mountains

引用

Journal of Mountain Science 2020年第4期17卷 884-897页

作者： LIU Yang CHEN Xi HAO Jian-Sheng LI Lan-hai State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Ili Station for Watershed Ecosystem Research Chinese Academy of SciencesXinyuan 835800China Research Center for Ecology and Environment of Central Asia Chinese Academy of SciencesUrumqi 830011China Xinjiang Regional Center of Resources and Environmental Science Instrument Chinese Academy of SciencesUrumqi 830011China

Obtaining the spatial distribution of snow cover in mountainous areas using the optical image of remote sensing technology is difficult because of cloud and fog. In this study, the object-based principle component analysis–support vector machine(PCA–SVM) method is proposed for snow cover mapping through the integration of moderateresolution imaging spectroradiometer(MODIS) snow cover products and the Sentinel-1 synthetic aperture radar(SAR) scattering characteristics. First, derived from the Sentinel-1 A SAR images, the feature parameters, including VV/VH backscatter, scattering entropy, and scattering alpha, were used to describe the variations of snow and non-snow covers. Second, the optimum feature combinations of snow cover were formed from the feature parameters using the principle component analysis(PCA) algorithm. Finally, using the optimum feature combinations, a snow cover map with a 20 m spatial resolution was extracted by means of an object-based SVM classifier. This method was applied in the study area of the Xinyuan County, which is located in the western part of the Tianshan Mountains in Xinjiang, China. The accuracies in this method were analyzed according to the data observed at different experimental sites. Results showed that the snow cover pixels of the extraction were less than those in the actual situation(FB1=93.86, FB2=59.78). The evaluation of the threat score(TS), probability of detection(POD), and false alarm ratio(FAR) for the snow-covered pixels obtained from the two-stage SAR images were different(TS1=86.84, POD1=90.10, FAR1=4.01;TS2=56.40, POD2=57.62, FAR2=3.62). False and misclassifications of the snow cover and non-snow cover pixels were found. Although the classifications were not highly accurate, the approach showed potential for integrating different sources to retrieve the spatial distribution of snow covers during a stable period.

关键词： snow cover Estimation Sentinel-1/2 MODIS Machine 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

Review of snow water equivalent microwave remote sensing

引用

Science China Earth Sciences 2016年第4期59卷 731-745页

作者： SHI JianCheng XIONG Chuan JIANG LingMei State Key Laboratory of Remote Sensing Sciences Jointly Sponsored by Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences and Beijing Normal University and Joint Center for Global Change Studies State Key Laboratory of Remote Sensing Sciences Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences School of Geography Beijing Normal Universityand Joint Center for Global Change Studies

Accurate quantitative global scale snow water equivalent information is crucial for meteorology, hydrology, water cycle and global change studies, and is of great importance for snow melt-runoff forecast, water resources management and flood control. With land surface process model and snow process model, the snow water equivalent can be simulated with certain accuracy, with the forcing data as input. However, the snow water equivalent simulated using the snow process models has large uncertainties spatially and temporally, and it may be far from the needs of practical applications. Thus, the large scale snow water equivalent information is mainly from remote sensing. Beginning with the launch of Nimbus-7 satellite, the research on microwave snow water equivalent remote sensing has developed for more than 30 years, researchers have made progress in many aspects, including the electromagnetic scattering and emission modeling, ground and airborne experiments, and inversion algorithms for future global high resolution snow water equivalent remote sensing program. In this paper, the research and progress in the aspects of electromagnetic scattering/emission modeling over snow covered terrain and snow water equivalent inversion algorithm will be summarized.

关键词： snow Microwave remote sensing Model Inversion

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

snow resisting capacity of Caragana microphylla and Achnatherum splendens in a typical steppe region of Inner Mongolia,China

引用

Journal of Arid Land 2020年第2期12卷 294-302页

作者： YAN Min ZUO Hejun WANG Haibing DONG Zhi LI Gangtie Key Laboratory of Aeolian Physics and Desertification Control Engineering Inner Mongolia Autonomous RegionCollege of Desert Control Science and EngineeringInner Mongolia Agricultural UniversityHohhot 010018China Forestry College Shandong Agricultural UniversityTai'an 271018China

snow resisting capacity of vegetation is important for secondary distribution of water resources in seasonal snow areas of grassland because it affects the regeneration,growth and nutrient circulation of vegetation in *** study investigated vegetation characteristics(canopy height,canopy length and crown width)of Caragana microphylla Lam.(shrub)and Achnatherum splendens(Trin.)Nevski.(herb),and snow morphologies(snow depth,snow width and snow braid length)in a typical steppe region of Inner Mongolia,China in *** the influence of vegetation characteristic on snow resisting capacity(the indices of bottom area of snow and snow volume reflect snow resisting capacity)was *** results showed that snow morphology depends on vegetation characteristics of shrub and *** canopy height was found to have the greatest influence on snow depth and the crown width had the greatest influence on snow *** canopy length was found to have little influence on morphological parameters of *** the windward areas of *** and *** were within the ranges of 0.0-0.5 m2 and 0.0-8.0 m2,respectively,the variation of snow cover was large;however,beyond these areas,the variation of snow cover became gradually *** potential area of snow retardation for a single plant was 1.5-2.5 m2 and the amount of snow resistance was 0.15-0.20 *** bottom area of snow and snow volume(i.e.,snow resisting capacity)of clumped *** and *** was found to be 4 and 25 times that of individual plant,*** results could provide a theoretical basis both for the estimation of snow cover and the establishment of a plant-based technical system for the control of windblown snow in the typical steppe region of Inner Mongolia.

关键词： herb shrub snow cover snow resisting capacity field observation steppe

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

Characteristics and Influencing Factors of Microplastics in snow in the Inner Mongolia Plateau, China

引用

Engineering 2024年第6期37卷 69-77页

作者： Hongwei Yu Junrong Shao Huawei Jia Diga Gang Baiwen Ma Chengzhi Hu State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Changjiang Survey PlanningDesign and Research Co.Ltd.Wuhan 430010China

Microplastics(MPs;<5 mm)have become one of the most prominent global environmental pollution *** can spread to high altitudes through atmospheric transport and can be deposited by rainfall or snowfall,potentially thre... 详细信息

Microplastics(MPs;snowfall,potentially threatening the structure and function of natural *** in terrestrial and aquatic ecosystems alter the growth and functional characteristics of ***,little attention has been given to the possible harm associated with MPs deposited in snow,particularly in the context of global climate *** collected from surface snow in the Inner Mongolia Plateau,China,were used for quantitative analysis and *** results showed that MPs were easily detected,and the related concentration was approximately(68±10)–(199±22)MPsL1 in snow *** were the most common morphology,the polymer composition was largely varied,and the abundance and composition of MPs were linked to human activity to a great ***-throughput sequencing results showed that the composition and abundance of microorganisms also differed in snow samples from areas with different MP pollution characteristics,indicating a considerable difference in microbial functional *** may have an interference effect on the individual growth and functional expression of microorganisms in *** addition,the results showed that functional living areas(e.g.,landfills and suburban areas)in cities play an important role in the properties of *** instance,the highest abundance of MPs was found in thermal power plants,whereas the abundance of polymers per sample was significantly lower in the suburban *** MP contaminants hidden in snow can alter microbial structure and function and are therefore a potential threat to ecosystem health.

关键词： Human activities snow Microplastics Microbial community Urban function Environmental effect

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

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：