检索结果-南通市图书馆

我国中高纬度地区冻融指数变化与冷暖急转现象

在线全文

学校读者我要写书评

暂无评论

干旱区研究 2020年第2期37卷 275-281页

作者：代海燕陈高娃吴建华杨丽萍都瓦拉内蒙古生态与农业气象中心内蒙古呼和浩特010051 呼伦贝尔市气象局内蒙古呼伦贝尔021008 赤峰市气象局内蒙古赤峰024000

利用我国中高纬度地区13个国家基准气候站近30 a日平均气温数据,分析中高纬度区域年冻融指数和冻融日数的变化趋势,结果表明:①近30 a研究区融化指数(thawing index,TI)处于显著上升过程,冻结指数(freezing index,FI)呈微弱上升趋势。... 详细信息

利用我国中高纬度地区13个国家基准气候站近30 a日平均气温数据,分析中高纬度区域年冻融指数和冻融日数的变化趋势,结果表明:①近30 a研究区融化指数(thawing index,TI)处于显著上升过程,冻结指数(freezing index,FI)呈微弱上升趋势。②融化日数的上升和冻结日数下降趋势不显著。③日平均TI呈显著上升,日平均FI则微弱下降,小于-10℃的天数呈微弱上升趋势。冷暖季节日均气温有两极化发展趋势。④研究区大于10℃累计积温显著增加,小于-10℃累计积温呈下降趋势,冷暖在向两极发展的同时,过渡期日数显著缩短,冷暖急转现象尤为明显。⑤TI各指标的波动明显小于FI,TI与纬度和海拔呈显著负相关,FI则与纬度和海拔呈正相关,海拔对TI的影响要大于FI,纬度和海拔越高,FI和冻结日数的变化越小,而对应的融化指标波动越大。整体来看,我国中高纬地区从20世纪90年代后存在增温减缓、冷暖季日均气温两极化及冷暖急转现象较为明显。

关键词：冻结指数融化指数气候异常中高纬地区中国

Exploitation of symmetry in periodic Self-Consistent-Field ab initio calculations: application to large three-dimensional compounds

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2014年第10期57卷 1418-1426页

作者： DE la PIERRE Marco ORlaNDO Roberto FERRABONE Matteo ZICOVICH-WILSON Claudio M. DOVESI Roberto Dipartimento di Chimica Università di Torino and NIS Nanostructured Interfaces and Surfaces Centre of Excellence Via P. Giuria 7 10125 Torino Italy Nanochemistry Research Institute Department of Chemistry Curtin University GPO Box U1987 Perth WA 6845 Australia Facultad de Ciencias Universidad Autónoma del Estado de Morelos Av. Universidad 1001 Col. Chamilpa 62209 Cuernavaca (Morelos) Mexico

Symmetry can dramatically reduce the computational cost （running time and memory allocation） of Self-Consistent-Field ab initio calculations for crystalline systems. Crucial for running time is use of symmetry in the evaluation of one- and two-electron integrals, diagonalization of the Fock matrix at selected points in reciprocal space, reconstruction of the density matrix. As regards memory allocation, full square matrices （overlap, Fock and density） in the Atomic Orbital （AO） basis are avoided and a direct transformation from the packed AO to the SACO （Symmetry Adapted Crystalline Orbital） basis is per- formed, so that the largest matrix to be handled has the size of the largest sub-block in the latter basis. We here illustrate the effectiveness of this scheme, following recent advancements in the CRYSTAL code, concerning memory allocation and direct basis set transformation. Quantitative examples are given for large unit cell systems, such as zeolites （all-silica faujasite and silicalite MF1） and garnets （pyrope）. It is shown that the full SCF of 3D systems containing up to 576 atoms and 11136 Atomic Orbitals in the cell can be run with a hybrid functional on a single core PC with 500 MB RAM in about 8 h.

关键词： point symmetry Symmetry Adapted Crystalline Orbitals Fock matrix density matrix CPU time memory allocation quantum-mechanical calculations CRYSTAL code

Two Innovative Techniques to Study the Environmental Impacts of Urban Forms

在线全文

学校读者我要写书评

暂无评论

Two Innovative Techniques to Study the Environmental Impacts...

美仁牦牛MYL 9基因克隆、生物信息学分析及组织表达研究

第四届粤港澳可持续发展研讨会

作者： U wa TANG Department of Civil and Environmental Engineering University of Macau

This paper introduces two innovative techniques,i.e.,the vehicle-following measuring technique and the high-spatial resolution air/noise modeling technique,that have been used recently to study of urban environment in the Macao *** related interna- tional conference papers have been awarded as one of the best student papers in the annual din- ner of the Hong Kong Society for Transportation Studies in 2007 and the annual dinner of the International Association of Chinese Professionals in Geographic Information Sciences in 2008. By using the vehicle-following measuring technique,vehicle gaseous emissions(NO, CO,CO and HC)and driver’s particle exposures(PM1,PM2.5,and PM10)have been measured during heavy traffic congestion in urban *** with the traditional la- boratory tests,the vehicle-following measurement technique can obtain a wide variety of vehi- cle emission data on the road as cooperation from the vehicle’s owners is no longer necessary. By using the high-spatial resolution modeling technique,traffic-induced air and noise pollu- tions in front of individual building facades on both sides of the road can be *** two innovative techniques have the capability to provide city decision-makers with a different perspective on vehicle transport and urban form that both impact air quality and noise.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

中国畜牧兽医 2024年第4期51卷 1410-1419页

作者：马荣喇永福包鹏甲郭宪路建卫扎老赵雪梁春年成述儒甘肃农业大学兰州730070 中国农业科学院兰州畜牧与兽药研究所甘肃省牦牛繁育工程重点实验室农业农村部青藏高原畜禽遗传资源育种重点实验室兰州730050 合作市佐盖多玛乡畜牧站合作747000 合作市农畜产品质量安全检测检验中心合作747000

【目的】克隆美仁牦牛肌球蛋白轻链9(myosin light chain 9,MYL9)基因CDS区并对其进行生物信息学分析,检测MYL 9基因的组织表达特征,为探究该基因功能提供一定理论依据。【方法】以美仁牦牛肌肉组织cDNA为模板,利用PCR扩增并克隆美仁牦... 详细信息

【目的】克隆美仁牦牛肌球蛋白轻链9(myosin light chain 9,MYL9)基因CDS区并对其进行生物信息学分析,检测MYL 9基因的组织表达特征,为探究该基因功能提供一定理论依据。【方法】以美仁牦牛肌肉组织cDNA为模板,利用PCR扩增并克隆美仁牦牛CDS区序列,与其他物种进行相似性比对及系统进化树构建;通过在线软件对MYL9蛋白进行生物信息学分析,利用实时荧光定量PCR检测MYL 9基因在美仁牦牛心脏、肝脏、脾脏、肺脏、肾脏、肌肉、脂肪和睾丸组织中表达情况。【结果】美仁牦牛MYL 9基因CDS区长516 bp,共编码171个氨基酸。系统进化树结果显示,美仁牦牛与野牦牛、普通牛亲缘关系最近,与高山倭蛙亲缘关系最远。MYL9蛋白分子式为C 858 H 1324 N 234 O 274 S 12,原子数为2702,理论等电点为4.85,不稳定系数和总平均亲水性分别为37.22和―0.772,属于稳定亲水性蛋白。MYL9蛋白无信号肽和跨膜螺旋结构,属于非分泌性蛋白;主要定位于线粒体、细胞核、细胞质中,具有17个特异性磷酸化位点。MYL9蛋白二级结构主要由α-螺旋、无规则卷曲、β-折叠和延伸链构成,三级结构预测结果与二级结构一致。实时荧光定量PCR结果显示,MYL 9基因在美仁牦牛心脏、肝脏、脾脏、肺脏、肾脏、肌肉、脂肪和睾丸组织中均表达,且肝脏和肌肉组织中表达量显著高于其他组织(P<0.05)。【结论】本研究成功克隆美仁牦牛MYL 9基因CDS区,探究了MYL 9基因的生物学功能及组织表达特征,研究结果为进一步探究牦牛MYL 9基因功能特征提供了参考。

关键词：美仁牦牛 MYL 9基因克隆生物信息学组织表达

Salt Dynamics in Rhizosphere of Puccinellia ciliata Bor. in a Loamy Soil

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2005年第6期15卷 784-791页

作者： ZHANG Zhen-Hua C. TANG Z. RENGEL Agricultural Resource and Environmental Research Center Jiangsu Academy of Agricultural Sciences Nanjing 210014 （China）. Soil Science and Plant Nutrition School of Earth and Geographical Sciences The University of Western Australia 35 Stirling Highway Crawley WA 6009 （Australia） CRC Plant-Based Management of Dryland Salinity The University of Western Australia 35 Stirling Highway Crawley WA 6009 （Australia） Department of Agricultural Sciences La Trobe University Bundoora Vic 3086 （Australia）

A glasshouse experiment using a rhizobox technique was conducted to examine salt dynamics in the rhizosphere of a salt-tolerant grass, Puccinellia ciliata Bor. ’Irwin Hunter’, grown in a loamy soil, and to study the effect of rainfall flush on salt accumulation in the rhizosphere. The rhizobox (10 × 5.5 × 50 cm) had a nylon mesh (1 μm) positioned vertically in the middle to create two compartments filled with soil amended with 1 g NaCl kg-1. The plants were grown in one compartment only. Flushed treatments received 275 mL of deionized water two days before harvest. In the plant-growing compartment, soils were sectioned vertically at 5 cm intervals. Significant differences in soil electrical conductivity (EC) (P lant compartment (rhizosphere), soil cores were taken horizontally at depths of 5, 20 and 40 cm and sliced at 1, 2, 3, 4, 5, 7, 10, 15 and 20 mm away from the roots. Soil EC and Cl- concentration at the 5 and 20 cm depths, and Na+ concentration at the 5 cm depth significantly decreased (P way from the root, but no significant differences were observed in soil pH and concentrations of the K+ and Ca2+. The flush treatment only had significant influence on soil EC, pH, and Cl- concentration at the 20 cm depth. Thus, salt accumulation could occur in the rhizosphere of salt-tolerant species on saline soils, and the periodic low rainfall might not have a strong influence on salt distribution in the rhizosphere and/or root zone.

关键词： leaching Puccinellia ciliata Bor. rhizosphere salt dynamics

用Himawari-8静止气象卫星的草原火蔓延仿真

在线全文

学校读者我要写书评

暂无评论

计算机仿真 2022年第9期39卷 201-207页

作者：刘洋玉山都瓦拉杨晓颖内蒙古师范大学地理科学学院内蒙古呼和浩特市010022 内蒙古自治区遥感与地理信息系统重点实验室内蒙古呼和浩特市010022 中国农业科学院草原研究所内蒙古呼和浩特市010022

针对传统草原火蔓延模拟模型获取草原火蔓延初速度困难,模型中静态气象数据精度低的问题,依托高时间分辨率Himawari-8结合时序线性外推法代替实验获取草原火蔓延初速度,利用GRAPES_MESO气象数值预报产品作为高精度动态气象数据,地理元... 详细信息

针对传统草原火蔓延模拟模型获取草原火蔓延初速度困难,模型中静态气象数据精度低的问题,依托高时间分辨率Himawari-8结合时序线性外推法代替实验获取草原火蔓延初速度,利用GRAPES_MESO气象数值预报产品作为高精度动态气象数据,地理元胞自动机结合王正非草原火蔓延模型,对一定时间内草原火场蔓延边界进行预测模拟。预测结果与Himawari-8下一周期实际影像提取的火情时空一致性较高,得到蔓延范围面积相对偏差Bias范围在1.49%-42.87%;蔓延边界均方根误差BRMSE范围在1.43-22.14个像元;像元平均绝对误差CMAPE为18.09%;模型正确模拟区域为84.68%。上述算法可用于监测草原火蔓延过程的重现及趋势预测方面的应用。

关键词：草原火火蔓延模拟线性外推法

玫瑰花中新唢呐草素Ⅰ的分离、含量测定和体外活性研究

在线全文

学校读者我要写书评

暂无评论

天然产物研究与开发 2022年第8期34卷 1319-1324页

作者：萨仁高娃苏龙嘎才仁拉毛齐和日玛内蒙古医科大学民族医药创新中心内蒙古医科大学药学院呼和浩特010110

采用葡聚糖凝胶柱层析和半制备高效液相色谱法,从阿尔山玫瑰花提取物中分离纯化得到纯度较高(95.48%)的新唢呐草素I,并鉴定其化学结构;同时采用高效液相色谱法测定了11种不同产地的玫瑰花中新唢呐草素I含量,其含量为0.7%~7.4%;体外活性... 详细信息

采用葡聚糖凝胶柱层析和半制备高效液相色谱法,从阿尔山玫瑰花提取物中分离纯化得到纯度较高(95.48%)的新唢呐草素I,并鉴定其化学结构;同时采用高效液相色谱法测定了11种不同产地的玫瑰花中新唢呐草素I含量,其含量为0.7%~7.4%;体外活性实验结果表明,新唢呐草素I对α-葡萄糖苷酶有较强的抑制活性,IC为10.0μg/mL,并不同产地玫瑰花提取物均显示抑制活性;新唢呐草素I也具有较强的DPPH自由基清除能力,半数清除率IC为8.1μg/mL,不同产地玫瑰花提取物均有清除DPPH自由基能力。而随着玫瑰花中新唢呐草素I含量的增加,其α-葡萄糖苷酶抑制活性和清除DPPH自由基能力有增强的趋势,但无显著性差异;本研究为玫瑰花提取物的降低餐后血糖活性成分的研究提供了实验依据。

关键词：玫瑰花新唢呐草素I 抑制α-葡萄糖苷酶活性抗氧化性

内蒙古干湿环境演变与地区生态建设优势气候背景分析

在线全文

学校读者我要写书评

暂无评论

干旱区地理 2019年第4期42卷 745-752页

作者：代海燕李丹娜日苏陈素华都瓦拉内蒙古生态与农业气象中心

通过内蒙古地区近46 a降水和潜在蒸散量以及湿润度在气温突变前后的倾向率和差值变化分析,得出该区域主要植被类型干湿环境演变的时空变化特征。研究结果表明:降水在气温突变前"东增西减",突变后呈相反的变化趋势。46 a降水倾向率增加... 详细信息

通过内蒙古地区近46 a降水和潜在蒸散量以及湿润度在气温突变前后的倾向率和差值变化分析,得出该区域主要植被类型干湿环境演变的时空变化特征。研究结果表明:降水在气温突变前"东增西减",突变后呈相反的变化趋势。46 a降水倾向率增加区域主要集中在呼伦贝尔市东部和乌兰察布市以西大部地区;潜在蒸散量在气温突变前呈减少趋势,突变后有增加趋势,突变后潜在蒸散量明显小于突变前。内蒙古46 a潜在蒸散量倾向率大部地区偏小,偏大区域仅存在于中东部偏北地区,气温突变后全区大部地区存在明显的"蒸发悖论";大兴安岭西麓和乌兰察布市以西地区突变后湿润度增加明显,暖湿的气候环境有利于当地植被建设和生态恢复,内蒙古东南部、呼伦贝尔草原和锡林郭勒盟草原区有暖干化趋势,上述草原区存在潜在退化风险。

关键词：内蒙古气候变化降水量潜在蒸发量湿润指数

A proto-monsoonal climate in the late Eocene of Southeast Asia:Evidence from a sedimentary record in central Myanmar

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2023年第1期14卷 46-63页

作者： Huasheng Huang Robert J.Morley Alexis Licht Guillaume Dupont-Nivet Daniel Pérez-Pinedo Jan Westerweel Zaw Win Day wa.a.ng Eko Budi Lelono Galina N.Aleksandrova Ramesh K.Saxena Carina Hoorn Institute for Biodiversity and Ecosystem Dynamics(IBED) University of Amsterdam1090 GE AmsterdamThe Netherlands Palynova Ltd. 1 Mow Fen RoadLittleportCambridgeshire CB61PYUK Department of Earth Sciences Royal HollowayUniversity of LondonEghamSurrey TW200EXUK Centre de Recherche et d'Enseignement de Géosciences de I'Environnement(CEREGE) Aix-en-ProvenceFrance Institut fur Geowissenschaften Universität Potsdam14476 PotsdamGermany Géosciences Rennes CNRS and Universitéde Rennes 135042 Rennes CedexFrance Geology Department Shwe Bo UniversitySagaing RegionMyanmar Department of Geology University of YangonPyay RoadYangonMyanmar Badan Geologi Jl.Soekarno Hatta No 444BandungBandung 40254Indonesia Geological Institute Russian Academy of SciencesPyzhevsky Pereulok 7119017 MoscowRussia Birbal Sahni Institute of Palaeosciences 53 University RoadLucknow 226007India Department of Earth Sciences University of FlorenceVia G.La Pira 450121 Florenceltaly Department of Earth Sciences Memorial University of New-foundlandSt.John'sNewfoundland A1B 3X5Canada

The Burma Terrane has yielded some of the earliest pieces of evidence for monsoonal rainfall in the Bay of ***,Burmese ecosystems and their potential monsoonal imprint remain poorly *** study focuses on the late Eocene Yaw Formation(23°N)in central Myanmar,which was located near the equator(c.5°N)during the *** quantitatively assessed the past vegetation,climate,and depositional environments with sporomorph diagrams,bioclimatic analysis,and sequence *** calculated the palynological diversity and drew inferences with rarefaction analysis by comparing with four other middle to late Eocene tropical *** results highlight a high floristic diversity for the palynoflora throughout the section formed by six pollen zones characterized by different *** indicate that lowland evergreen forests and swamps dominated in the Eocene Burmese deltaic plains while terra firma areas were occupied by seasonal evergreen,seasonally dry,and deciduous *** vegetation pattern is typical to what is found around the Bay of Bengal today and supports a monsoon-like climate at the time of the Yaw *** analysis further suggests that in the late Eocene,the Yaw Formation was more seasonal,drier,and cooler compared to modern-day climate at similar near-equatorial *** seasonal and drier conditions can be explained by a well-marked seasonal migration of the Intertropical Convergence Zone(ITCZ),driver of proto-monsoonal *** temperatures in the late Eocene of central Myanmar may be due to the lack of adequate modern analogues for the Eocene monsoonal climate,while those found at other three Eocene Asian paleobotanical sites(India and South China)may be caused by the effect of canopy evapotranspirational *** data suggest that paleoenvironmental change including two transgressive-regressive depositional sequences is controlled by global sea level change,which may be driven by cl

关键词： Bioclimatic analysis Diversity Monsoon Palynology Sequence biostratigraphy Southeast Asia