检索结果-南通市图书馆

In situ measurement of environmental γ radiation dose rates of key nuclides for large radioactive surface sources

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2025年第1期36卷 69-79页

作者： Ze-Qian Wu Jian Sun wei-Qi Huang Bai-Rong wang Jin-Xing Cheng Jiang-Feng Wu Yong-hong wang Biao Yuan Sheng Qi Kun Shan Institute of NBC Defence Beijing 102205China Beijing New-High Technology Academy Beijing 100094China

To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface *** methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface *** address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration *** methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically ***,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface *** situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.

关键词： Environmentalγradiation dose rate HPGespectrometer Key radionuclides Radioactive surface source

Sharp Isolated Toughness Bound for Fractional(k,m)-Deleted Graphs

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2025年第1期41卷 252-269页

作者： wei GAO wei-fan wang Yao-jun CHEN School of Mathematics Hohai UniversityNanjing 210098China Department of Mathematics Zhejiang Normal UniversityJinhua 321004China Department of Mathematics Nanjing UniversityNanjing 210093China

A graph G is a fractional(k,m)-deleted graph if removing any m edges from G,the resulting subgraph still admits a fractional *** k≥2 and m≥1 be ***[2m/k]^(*)=[2m/k]if 2m/k is not an integer,and[2m/k]^(*)=[2m/k]-1 if 2m/k is an *** this paper,we prove that G is a fractional(k,m)-deleted graph if δ(G)≥k+m and isolated toughness meets I(G)>{3-1/m,if k=2 and m≥3,k+[2m/k]^(*)m+1-[2m/k]^(*);***,we show that the isolated toughness bound is tight.

关键词： graph isolated toughness fractional k-factor fractional(k,m)-deleted graph

Glycemic index of cereals and tubers produced in China

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2006年第21期12卷 3430-3433页

作者： Yue-Xin Yang hong-wei wang hong-Mei Cui Yan wang Lian-Da Yu Shi-Xue Xiang Shui-Ying Zhou Institute of Nutrition and Food Safety Chinese Center for Disease Control and Prevention Beijing 100050 China Department of Endocrinology the First Hospital of Chaoyang Liaoning Province China Center for Disease Control and Prevention of Ningxia Autonomous Regio n Yinehuan 750004 Ningxia Hui Minority Autonomous Region China Sichuan Center for Disease Control and Prevention Chengdu 610031 Sichuan Province China Huangshi Institute of Health Inspection Huangshi 435000 Hubei Province China

AIM： To determine the GI of some cereals and tubers produced in China in an effort to establish the database of glycemic index （GI） of Chinese ***： Food containing 50 g carbohydrate was consumed by 8-12 healthy adults after they have been fasted for 10 h and blood glucose was monitored for 2 h. Glucose was used as reference food. GI of food was calculated according to a standard ***： GI of 9 types of sugar and 60 kinds of food were ***： Food GI is mainly determined by nature of carbohydrate and procession. Most of cereals and tubers produced in China have similar GI with their counterparts produced in other countries.

关键词： Glycemic Index Cereals Tubers Carbohydrate

Health Safety of Main Water Pipe Materials Supplied in China Market

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

Biomedical and Environmental Sciences 2006年第2期19卷 110-117页

作者： KAI LU LIANG DING hong-wei wang HAI-NING JING XlAO-NING ZHAO SHAO-BIN LIN YA-DONG LI YIN-LONG JIN FENG-MAO LIU SHU-REN JIANG China College of Science China Agricultural University Beijing 100094China Institute of Environment and Health Related Product Safety Chinese Center for Disease Control and Prevention Beijing 100021 China

Objective To assess the health safety of copper, steel and plastic water pipes by field water quality investigations. Methods Four consumers were randomly selected for each type of water pipes. Two consumers of every type of the water pipes had used the water pipes for more than 1 year and the other 2 consumers had used the water pipes for less than 3 months. The terminal volume of tap water in copper and steel water pipes should be not less than 0.1 liter, whereas that in plastic water pipes should be not less than 1 liter. Results The mean values of the experimental results in the second field water quality investigation of the copper and steel water pipes met the Sanitary Standards for Drinking Water Quality. The items of water sample of the plastic water pipes met the requirements of the Sanitary Standards for Drinking Water Quality. Conclusion Copper, steel, and plastic pipes can be used as drinking water pipes.

关键词： Copper Steel Plastic Water pipes Health safety

Reduced graphene oxide membrane as supporting film for high-resolution cryo-EM

在线全文

学校读者我要写书评

暂无评论

Biophysics Reports 2021年第3期7卷 227-238页

作者： Nan Liu Liming Zheng Jie Xu Jia wang Cuixia Hu Jun Lan Xing Zhang Jincan Zhang Kui Xu Hang Cheng Zi Yang Xin Gao Xinquan wang Hailin Peng Yanan Chen hong-wei wang Ministry of Education Key Laboratory of Protein Sciences Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua University Tsinghua-Peking Joint Center for Life Sciences Tsinghua University Center for Nanochemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking University Joint Graduate Program of Peking-Tsinghua-NIBS School of Life SciencesTsinghua University Beijing Frontier Research Center for Biological Structures Tsinghua University Academy for Advanced Interdisciplinary Studies Peking University School of Materials Science and Engineering Tianjin University

Although single-particle cryogenic electron microscopy(cryo-EM) has been applied extensively for elucidating many crucial biological mechanisms at the molecular level, this technique still faces critical challenges, the major one of which is to prepare the high-quality cryo-EM specimen. Aiming to achieve a more reproducible and efficient cryo-EM specimen preparation, novel supporting films including graphene-based two-dimensional materials have been explored in recent years. Here we report a robust and simple method to fabricate EM grids coated with single-or few-layer reduced graphene oxide(RGO) membrane in large batch for high-resolution cryo-EM structural determination. The RGO membrane has decreased interlayer space and enhanced electrical conductivity in comparison to regular graphene oxide(GO) membrane. Moreover, we found that the RGO supporting film exhibited nice particle-absorption ability, thus avoiding the air–water interface problem. More importantly, we found that the RGO supporting film is particularly useful in cryo-EM reconstruction of sub-100-k Da biomolecules at near-atomic resolution, as exemplified by the study of RBD-ACE2 complex and other small protein molecules. We envision that the RGO membranes can be used as a robust graphene-based supporting film in cryo-EM specimen preparation.

关键词： 3D reconstruction Reduced graphene oxide Cryo-EM Air–water interface

Effects of mode of reproduction on genetic polymorphism and divergence in wild yams(Dioscoreaceae:Dioscorea)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plant Diversity 2025年第1期47卷 136-147页

作者： Xin wang Qing-hong Feng Zhi-Hua Zeng Zhi-Qiang Zhang Jie Cai Gao Chen De-Zhu Li hong wang wei Zhou Germplasm Bank of Wild Species&Yunnan Key Laboratory of Crop Wild Relatives Omics Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China University of Chinese Academy of Sciences Beijing 100049China Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology Institute of BiodiversitySchool of Ecology and Environmental ScienceYunnan UniversityKunmingYunnan 650504China Research Institute of Tropical Forestry Yunnan Academy of Forestry and GrasslandXishuangbannaYunnan 666102China CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China Key Laboratory of Phytochemistry and Natural Medicines Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China Lijiang Forest Biodiversity National Observation and Research Station Kunming Institute of BotanyChinese Academy of SciencesLijiangYunnan 674100China

Evolutionary transitions from sexual to asexual reproduction should have significant influences on genetic divergence and polymorphism at the genome *** lineages with diverse reproductive systems provide opportunities to investigate this question using comparative approaches and studies of molecular *** investigated evidence for differences among the transcriptomes of 19 Dioscorea species(wild yams)with diverse reproductive *** included sexual species,those that propagate primarily by bulbils,and those with mixed sexual and asexual reproductive *** examined how transitions between these reproductive systems affected between-species divergence and within-species *** asexual species exhibited a reduced efficacy of natural selection and accumulation of deleterious mutations for both divergence and *** contrast,species with mixed reproductive strategies involving both seed and clonal reproduction showed no evidence of an increased fixation of harmful mutations at the divergence level,while an accumulation of genetic load present in polymorphism was *** study indicates that the genetic consequences of evolutionary transitions from sexual to predominantly clonal reproduction is likely to depend on both the duration and extent of asexuality occurring in populations.

关键词： Asexual Deleterious mutations Dioscorea Molecular evolution Selection

Temporal Stability of Sward Dry Matter and Nitrogen Yield Patterns in a Temperate Grassland

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2006年第6期16卷 735-744页

作者： XU hong-wei wang Ke J. S. BAILEY C. JORDAN A. WITHERS College of Environment and Resources Zhejiang University Hangzhou 310029 China Department of Agriculture and Rural Development Agricultural Food and Environmental Science Division Newforge Lane Belfast BT9 5PX （United Kingdom） Department of Agriculture and Rural Development Plant Testing Station 50 Houston Road Crossnacreevy Belfast BT6 9SH （United Kingdom）

The objectives of the present study were to examine the spatial patterns of sward dry matter (DM) and nitrogen (N) yields in a grass silage field at first, second, and third cuts over a 3-year period; quantify their temporal stabilities with temporal stability maps; and assess the potential for site-specific management in each pasture-growing period using classified management maps. At cut 1, the spatial patterns of DM and N yields proved to be well defined and temporally stable and were likely to be due to differences in the net N mineralization rates across the field during spring. In contrast, at cut 2, the patterns of DM production were patchy and temporally unstable. It was concluded that, in principle, a simple site-specific approach to N fertilization would be possible in this field during spring at cut 1. At later harvests, the rationale for a site-specific approach to fertilizer management was less clear with logistics appearing to be more complex and less feasible.

关键词： cool temperate grassland dry matter yield spatial variability temporal stability

The secondary periodic elementβ_(p^(2)/p^(2)-1)and its applications

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2025年第1期68卷 207-222页

作者： Jianguo hong Xiangjun wang Yu Zhang Science College Shijiazhuang UniversityShijiazhuang 050035China School of Mathematical Sciences Nankai UniversityTianjin 300071China Center for Applied Mathematics Tianjin UniversityTianjin 300072China

Let p≥7 be a *** prove thatβ_(p^(2)/p^(2)-1)survives to E_(∞)in the Adams-Novikov spectral ***,using the Thom mapΦ:■,we can see that h0h3 also survives to E_(∞)in the classical Adams spectral *** an application ... 详细信息

关键词： stable homotopy groups of spheres Adams-Novikov spectral sequence in nite descent method

辽东宽甸和三家子地区花岗伟晶岩的锆石U-Pb年代学及其地质意义

在线全文

学校读者我要写书评

暂无评论

岩石学报 2017年第9期33卷 2675-2688页

作者：杨红王伟刘建辉中国地质科学院地质研究所北京100037

辽东宽甸和三家子地区辽河群中广泛存在花岗质伟晶岩脉或岩体,对其进行研究具有重要的构造意义。本文对两个地区侵入辽河群中的花岗伟晶岩样品进行岩石学、锆石LA-ICP-MS稀土微量元素和U-Pb定年的综合研究,获得侵入不同岩组地层中伟晶... 详细信息

辽东宽甸和三家子地区辽河群中广泛存在花岗质伟晶岩脉或岩体,对其进行研究具有重要的构造意义。本文对两个地区侵入辽河群中的花岗伟晶岩样品进行岩石学、锆石LA-ICP-MS稀土微量元素和U-Pb定年的综合研究,获得侵入不同岩组地层中伟晶岩的原岩年龄,并对其成因和构造环境进行了探讨。花岗伟晶岩主要矿物组合为石英+钾长石±钠长石±电气石±白云母,中粗粒结构或伟晶结构,块状构造。宽甸地区侵入高家峪组大理岩中的二处伟晶岩样品年龄分别为1842±7Ma和1864±8Ma;三家子地区侵入里尔峪组地层的二处伟晶岩样品年龄分别为1876±11Ma和1871±7Ma,侵入大石桥组的伟晶岩岩体年龄为1802±15Ma,侵入盖县组地层的伟晶岩年龄为1740±8Ma。宽甸地区伟晶岩(年龄1.86~1.84Ga)锆石阴极发光具振荡环带,Th/U大多>0.1,稀土配分模式主要显示岩浆锆石的特征,在Ce/Ce*-(Sm/La)_N图解上显示近岩浆锆石区域,花岗伟晶岩脉熔体可能是母岩浆初步结晶分异后的产物,较大保留了母岩浆的性质;三家子地区3个样品(年龄1.87~1.74Ga)锆石微区具低亮度无结构特征、Th/U<0.1,稀土配分模式显示热液锆石特征,在Ce/Ce*-(Sm/La)_N图解上偏热液锆石区域,此花岗伟晶岩脉可能是母岩浆高度结晶分异后的残余热液结晶而成,偏热液性质。三家子1个样品(年龄1.87Ga)锆石具弱振荡环带,ΣREE值较低,Eu/Eu*主要介于0.00~0.60,HREE总量低且平缓,显示深熔成因,其伟晶岩脉熔体可能直接来自含石榴石的原岩部分熔融而成的深熔脉体。本文研究的多期次花岗伟晶岩或与辽吉造山带周围1.89~1.82Ga的S型或I型花岗岩和深熔脉体具有亲缘关系,即大部分伟晶岩可能与1.89~1.82Ga的花岗质岩浆作用有关,一部分则与变质沉积岩系的深熔作用有关。从构造环境来看,辽吉造山带在碰撞后的构造折返过程中,从~1.87Ga到~1.74Ga至少130Myr的时间里一直处于伸展的构造机制。在主期花岗质岩浆上涌之后,大量残余岩浆或深熔脉体上涌至辽河群地层中形成伟晶岩的岩脉、岩墙或岩体。

关键词：胶-辽-吉带花岗伟晶岩辽河群辽吉花岗岩锆石U-Pb定年