期刊文献+
共找到1,174篇文章
< 1 2 59 >
每页显示 20 50 100
当代视听精品的大橱窗——’95四川国际电视节国际音响影视展简报
1
作者 雅风 《视听技术》 1995年第10期65-67,共3页
随着’95中国四川国际电视节帏幕的拉开,作为电视节组成部分之一的国际音响影视展9月22日在成都隆重开幕。 《视听技术》协办了这次盛会并在大展中设立了自己的展台。 这是当代最新视听设备的一次大汇展,也是我国民族视听工业的一次大... 随着’95中国四川国际电视节帏幕的拉开,作为电视节组成部分之一的国际音响影视展9月22日在成都隆重开幕。 《视听技术》协办了这次盛会并在大展中设立了自己的展台。 这是当代最新视听设备的一次大汇展,也是我国民族视听工业的一次大检阅。来自日本。 展开更多
关键词 电视节 家庭 响影 精品 放大器 专业音系统 中国大陆 扬声器 橱窗 听音室
下载PDF
观察与印象:第六届上海国际音响影视展概览
2
作者 钟音翔 《视听技术》 1998年第5期24-26,共3页
“人似飞鸿来有信”,4月10日, 我们抵达上海,参观在此地已举办了六届的国际音响影视展览会。 和往年一样,此届展览也分为两个展场,一在上海展览中心,参展厂商基本上是在同一个大厅里,让各自的器材加入到震耳欲聋的超级交响之中;一在贵... “人似飞鸿来有信”,4月10日, 我们抵达上海,参观在此地已举办了六届的国际音响影视展览会。 和往年一样,此届展览也分为两个展场,一在上海展览中心,参展厂商基本上是在同一个大厅里,让各自的器材加入到震耳欲聋的超级交响之中;一在贵都饭店。参展者各据一室,或大或小,让自己的器材有个较为独立的表演空间。 今年展览会在规模和热度上,都已不似去年。如果单凭主委会编印的会刊看,参展商不但没有减少。 展开更多
关键词 展览中心 响影 展览会 代理 市场经理 参展厂商 中国市场 给人深刻印象 新系列 万里行
下载PDF
展示当代视听技术 荟萃全球音响硕果——'94上海国际音响影视展巡礼
3
《视听技术》 1994年第3期58-67,共10页
四月二十一日这一天,上海展览中心肯定是全世界最热闹的地方之一。且不说如潮的人流,且不说眩目的灯光,光是一百多家展台上数百只齐鸣的扬声器就足以使这里的声压达到一百一十分贝以上。
关键词 扬声器 视听技术 AV放大器 展览会 解码器 发烧友 激光唱机 功率放大器 响影
下载PDF
缩节胺和硝普钠对棉花幼苗根际土壤酶活性及细菌群落的影响
4
作者 吴建飞 刘茜 +3 位作者 李璇 温天旺 杨文亭 汤飞宇 《棉花学报》 CSCD 北大核心 2023年第5期353-364,共12页
【目的】研究棉花幼苗施用缩节胺(1,1-dimethyl piperidinium chloride,DPC)和一氧化氮供体硝普钠(sodium nitroprusside,SNP)后根际土壤酶活性及细菌群落的变化,探讨与棉花幼苗生长相关的根际生物学指标。【方法】采用陆地棉品系A201... 【目的】研究棉花幼苗施用缩节胺(1,1-dimethyl piperidinium chloride,DPC)和一氧化氮供体硝普钠(sodium nitroprusside,SNP)后根际土壤酶活性及细菌群落的变化,探讨与棉花幼苗生长相关的根际生物学指标。【方法】采用陆地棉品系A201进行穴盘育苗试验。于棉花1叶1心期分别在叶片均匀涂抹50 mg·L^(-1)DPC、500μmol·L^(-1)SNP,以涂抹去离子水为对照。于3叶1心期取根际土壤分析蔗糖酶、脲酶、过氧化氢酶、碱性磷酸酶活性,采用16S rRNA测序技术分析根际细菌多样性。【结果】DPC和SNP处理显著促进棉花根系生长,显著提高茎粗和植株干物质质量。DPC处理显著提高土壤脲酶和蔗糖酶的活性,SNP处理显著提高土壤蔗糖酶活性但显著降低脲酶的活性,但是DPC和SNP处理均未显著影响过氧化氢酶和碱性磷酸酶活性。DPC处理显著提高髌骨菌门(Patescibacteria)的相对丰度和土壤细菌群落的辛普森多样性指数(Simpson's diversity index),显著降低了绿弯菌门(Chloroflexi)和酸杆菌门(Acidobacteria)的相对丰度以及土壤细菌群落的香农-维纳多样性指数(Shannon Wiener’s diversity index)。冗余分析显示,DPC处理组的酵母菌科(Saccharimonadaceae)、TM7a属细菌的相对丰度比SNP处理组和对照组高;SNP处理组的纤维弧菌属(Cellvibrionaceae)细菌相对丰度高于DPC处理组和对照组;DPC和SNP处理组的根瘤菌科(Rhizobiaceae)细菌的相对丰度高于对照组,硝化螺旋菌科(Nitrospiraceae)和硝化螺旋菌属(Nitrospira)细菌的相对丰度低于对照组。脲酶活性与酵母菌科、TM7a属细菌的相对丰度呈显著正相关关系。【结论】DPC和SNP能够促进棉花幼苗根系及植株生长,并影响棉苗根际的土壤酶活性及细菌群落结构。 展开更多
关键词 棉花 缩节胺 硝普钠 土壤酶 细菌群落 丰度 多样性
下载PDF
不同植物生长调节剂对冬小麦生长及产量的影响 被引量:3
5
作者 张飞雪 陈峰 +2 位作者 张书红 马延东 刘锐杰 《肥料与健康》 CAS 2023年第6期58-61,66,共5页
为考察不同植物生长调节剂对农作物生长状况及产量的影响,以氨基寡糖素、复硝酚钠和胺鲜酯为处理药剂,以复合肥(18-15-12)为药剂载体,于冬小麦播种前底施于土壤,测定了不同生育时期冬小麦的株高、主根长、须根数、分蘖数、叶片数、顶节... 为考察不同植物生长调节剂对农作物生长状况及产量的影响,以氨基寡糖素、复硝酚钠和胺鲜酯为处理药剂,以复合肥(18-15-12)为药剂载体,于冬小麦播种前底施于土壤,测定了不同生育时期冬小麦的株高、主根长、须根数、分蘖数、叶片数、顶节长、穗长、旗叶长、颖果数等指标。结果表明:氨基寡糖素在冬小麦前期能促苗生根,中期能促叶、增加分蘖数,提高冬小麦产量;复硝酚钠主要表现在中后期能促进冬小麦株高和旗叶的生长;胺鲜酯在冬小麦前期对茎叶、须根数,在中期对顶节长、颖果数具有促进作用,但后期对顶节长、旗叶长和颖果数有抑制作用;复硝酚钠和胺鲜酯均会降低冬小麦产量。 展开更多
关键词 植物生长调节剂 冬小麦 氨基寡糖素 复硝酚钠 胺鲜酯
下载PDF
谈谈吉湖农业开发项目的环境影响及其对策
6
作者 刘惠民 杨沂凤 《农村生态环境》 CSCD 1992年第2期13-17,共5页
本文对江西省最大的引进外资开发农业的吉湖项目进行了环境影响分析,突出中国有机农业的历史与现实,提出了保护生态环境的对策。
关键词 农业 开发项目 环境响影
下载PDF
从满族传统观念的转变看汉文化的响影 被引量:2
7
作者 刘志扬 《民族研究》 CSSCI 北大核心 1992年第6期83-91,共9页
一 行为的所有标准都是相对的,不同民族的差异,往往集中表现在各民族文化不同的特征上(所谓文化,在这里将其界定为生活方式),而不同的民族文化,又往往有不同的价值观。各民族独特的民族文化是在长期的、相对封闭的环境中形成的,具有排... 一 行为的所有标准都是相对的,不同民族的差异,往往集中表现在各民族文化不同的特征上(所谓文化,在这里将其界定为生活方式),而不同的民族文化,又往往有不同的价值观。各民族独特的民族文化是在长期的、相对封闭的环境中形成的,具有排他性和各美其美的民族优越感。这种各美其美的特征导致认为本民族的行为准则和道德规范总是好的。 展开更多
关键词 满族传统 观念的转变 汉文化 民族文化 民族优越感 道德规范 响影 美的特征 行为准则 价值观
原文传递
计算机应用技术对企业信息化的影响策略探析 被引量:11
8
作者 李玉荣 《电脑与电信》 2015年第7期80-81,共2页
随着社会经济的急速发展,互联网几乎走进了每一户家庭,计算机的普及不仅拉近了人们之间的距离,为人们的生活、工作提供了便利,而且计算机技术的应用已成为各个企业发展的必要因素。本文首先对计算机应用技术和企业信息化进行了简单的阐... 随着社会经济的急速发展,互联网几乎走进了每一户家庭,计算机的普及不仅拉近了人们之间的距离,为人们的生活、工作提供了便利,而且计算机技术的应用已成为各个企业发展的必要因素。本文首先对计算机应用技术和企业信息化进行了简单的阐述,然后对计算机应用技术对企业信息化的影响进行了分析,最后为如何运用计算机应用技术实现企业的信息化管理提供了一些建议。 展开更多
关键词 企业信息化 计算机应用技术 -
下载PDF
对关贸总协定影响我国移动通信工业的思考
9
作者 李进良 《移动通信》 北大核心 1993年第1期3-7,共5页
1992年我国移动通信业务获得很大发展,而移动通信工业却处于困境.1993年我国将重返美贸总协定,会产生怎样的影响?本文概述了总协定的基本内容,我国进口管理体制改革方案,思考了一些对策——合资、转第三产业、二次加工、开拓周边市场、... 1992年我国移动通信业务获得很大发展,而移动通信工业却处于困境.1993年我国将重返美贸总协定,会产生怎样的影响?本文概述了总协定的基本内容,我国进口管理体制改革方案,思考了一些对策——合资、转第三产业、二次加工、开拓周边市场、联合开发等,可供同行参考. 展开更多
关键词 移动通信 关贸总协定 响影
下载PDF
体育产业对江西省区域经济发展的影响研究
10
作者 谭文辉 黄平 《商场现代化》 北大核心 2007年第10Z期237-238,共2页
本文阐述了体育产业的概念,通过对江西省体育产业结构现状的分析,阐述了体育产业对江西省区域经济的影响,并在此基础上提出体育产业将为江西省经济持续发展发挥更重要的作用。
关键词 体育产业 区域经济 江西省
下载PDF
城市化对唐山市水环境的影响研究 被引量:3
11
作者 张月明 《水资源开发与管理》 2018年第1期50-53,共4页
本文针对唐山市城市建设现状,通过监测、分析城市化对水循环系统、水质变化、河流生态环境的影响,探讨水环境发展规律,选择种植对水质有很强净化作用的植物、改变工程调度方式衰减COD浓度、区域水生动物群落补救及合理配置水资源等措施... 本文针对唐山市城市建设现状,通过监测、分析城市化对水循环系统、水质变化、河流生态环境的影响,探讨水环境发展规律,选择种植对水质有很强净化作用的植物、改变工程调度方式衰减COD浓度、区域水生动物群落补救及合理配置水资源等措施助益水生态改善,最大利好城市发展。 展开更多
关键词 城市化 水循环 水质 水环境 唐山市
下载PDF
上海社区老年人健康促进生活方式影响因素分析 被引量:2
12
作者 王汉哲 许铭星 《应用数学进展》 2020年第11期2046-2052,共7页
目的:研究上海社区老年人健康促进生活方式现状及其影响因素。方法:采用一般情况调查表和中文版老年人健康促进生活方式量表对上海社区老年人基本情况和生活方式现状进行调查。结果:老年人健康促进生活方式量表平均得分为(96.63 &#1... 目的:研究上海社区老年人健康促进生活方式现状及其影响因素。方法:采用一般情况调查表和中文版老年人健康促进生活方式量表对上海社区老年人基本情况和生活方式现状进行调查。结果:老年人健康促进生活方式量表平均得分为(96.63 &#177;16.91)分。各量表得分依次为:饮食营养维度得分为(13.06 &#177;2.00)分,运动锻炼维度得分为(10.22 &#177;2.61)分,精神成长维度得分为(14.17 &#177;3.34)分,健康责任维度得分为(22.08 &#177;5.59)分,压力应对维度得分为(19.24 &#177;3.96)分,人际关系维度得分为(17.86 &#177;3.03)分。年龄、健康关注度、健康自我效能、公共健康设施健全程度和公共健康服务开展情况对老年人健康促进生活方式存在显著影响。结论:上海社区老年人健康促进生活方式水平为中等偏上,可通过提升健康自我效能、增加健康关注度、开展多种公共健康服务,健全公共健康设施来提高老年人健康促进生活方式水平,从而改善其健康状况。 展开更多
关键词 老年人 健康促进 生活方式 因素
下载PDF
Influencing factors analysis of hard limestone reformation and strength weakening under acidic effect
13
作者 HOU Ming-xiao HUANG Bing-xiang +2 位作者 ZHAO Xing-long JIAO Xue-jie ZHENG Chen-yang 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2446-2466,共21页
Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way t... Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines. 展开更多
关键词 hard roof acidic effect structural reformation strength weakening influencing factors
下载PDF
Temperature effects on the failure of deep circular tunnel under true-triaxial compression
14
作者 HUANG Lin-qi LIU Mao-lin +4 位作者 WANG Zhao-wei GUO Yi-de SI Xue-feng LI Xi-bing LI Chao 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3119-3141,共23页
The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The fa... The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The failure process of the inner walls of fine-grained granite specimens at different temperatures(25–600℃)was analyzed using a true-triaxial test system.The failure process,peak intensity,overall morphology(characteristics after failure),rock fragment characteristics,and acoustic emission(AE)characteristics were analyzed.The results showed that for the aforementioned type of granite specimens,the trend of the failure stress conditions changed with respect to the critical temperature(200℃).When the temperature was less than 200℃,the initial failure stress increased,final failure stress increased,and failure severity decreased.When the temperature exceeded 200℃,the initial failure stress decreased,final failure stress decreased,and failure severity increased.When the temperature was 600℃,the initial and final failure stresses of the specimens decreased by 60.93%and 19.77%compared with those at 200℃,respectively.The numerical results obtained with the software RFPA3D-Thermal were used to analyze the effect of temperature on the specimen and reveal the mechanism of the failure process in the deep tunnel surrounding rock. 展开更多
关键词 deep ground rock failure GRANITE thermal treatment true-triaxial test circular tunnel RFPA3D-Thermal
下载PDF
Characteristics and fate behavior of environmentally persistent free radicals in atmospheric particulate matter
15
作者 WANG Xueying CUI Long +2 位作者 XUE Yonggang HO Kinfai HUANG Yu 《地球环境学报》 CSCD 2024年第4期596-611,共16页
Background,aim,and scope Environmentally persistent free radicals(EPFRs)have received significant attention due to their longer lifetime and stable existence in various environments.The strong environmental migration ... Background,aim,and scope Environmentally persistent free radicals(EPFRs)have received significant attention due to their longer lifetime and stable existence in various environments.The strong environmental migration ability of particulate matter allows EPFRs to migrate over long-distance transport,thereby impacting the quality of the local atmospheric environment.Additionally,EPFRs can also adhere to atmospheric particles and interact with typical gaseous pollutants to affect atmospheric chemical reactions.EPFRs can produce some reactive organic species,promoting oxidative stress in the human body,damaging biological macromolecules and ultimately affecting the organism health.EPFRs are considered as a novel type of pollutant that affects human health.Despite their significance,there are few literatures available on the characteristics and fate behaviors of EPFRs up to date.Therefore,supplemental reviews are crucial for providing comprehensive understanding of EPFRs.Materials and methods This review summarizes the characteristics of EPFRs in particulate matter,outlines the generation mechanism and influencing factors of EPFRs,and the impacts of EPFRs on environmental quality and organism health.Results The content of EPFRs in particulate matter ranges from 1017 to 1020 spins∙g−1.Due to the strong mobility of atmospheric particulate matter,the long-term exposure to high levels of EPFRs may aggravate the impact of particulate matter on human health.The interaction between EPFRs and typical gaseous pollutants can alter their fate and influence atmospheric chemical reactions.EPFRs are mainly produced by transition metal elements and substituted aromatic hydrocarbons through electron transfer.Additionally,the chemical bond rupture of organic substances through heat treatment or ultraviolet radiation can also produce EPFRs,and heterogeneous reactions are capable producing them as well.The production of EPFRs is not only influenced by transition metal elements and precursors,but also by various environmental factors such as oxygen,temperature,light radiation,and relative humidity.Discussion EPFRs in atmospheric particulates matters are usually rich in fine particulates with obvious seasonal and regional variations.They can easily enter the human respiratory tract and lungs with inhalable particulates,thereby increasing the risk of exposure.Additionally,EPFRs in atmospheric particulates can interact with some typical gaseous pollutants,impacting the life and fate of EPFRs in the atmosphere,and alter atmospheric chemical reactions.Traditionally,EPFRs are generated by transition metal elements and substituted aromatic hydrocarbons undergoing electron transfer in the post-flame and cool-zone regions of combustion systems and other thermal processes to remove HCl,H2O or CO groups,ultimately produce semiquinones,phenoxyls,and cyclopentadienyls.Recent studies have indicated that EPFRs can also be generated under the conditions of without transition metal elemental.Organics can also produce EPFRs through chemical bond rupture during heat treatment or light radiation conditions,as well as through some heterogeneous reactions and photochemical secondary generation of EPFRs.The presence or absence of oxygen has different effects on the type and yield of EPFRs.The concentration,type,and crystal type of transition metal elements will affect the type,content,and atmospheric lifetime of EPFRs.It is generally believed that the impact of transition metal element types on EPFRs is related to the oxidation-reduction potential.The combustion temperature or heat treatment process significantly affects the type and amount of EPFRs.Factors such as precursor loading content,pH conditions,light radiation and relative humidity also influence the generation of EPFRs.EPFRs can interact with pollutants in the environment during their migration and transformation process in environmental medium.This process accelerates the degradation of pollutants and plays a crucial role in the migration and transformation of organic pollutants in environmental media.The reaction process of EPFRs may lead to the production of reactive oxygen species(ROS)such as∙OH,which can induce oxidative stress,inflammation and immune response to biological lung cells and tissues,leading to chronic respiratory and cardiopulmonary dysfunction,cardiovascular damage and neurotoxic effects,ultimately impacting the health of organisms.Conclusions The interaction mechanism between EPFRs in particulate matter and gaseous pollutants remains unclear.Furthermore,research on the generation mechanism of EPFRs without the participation of transition metals is not comprehensive,and the detection of EPFRs is limited to simple qualitative categories and lack accurate qualitative analysis.Recommendations and perspectives Further research should be conducted on the generation mechanism,measurement techniques,migration pathways,and transformation process of EPFRs.It is also important to explore the interaction between EPFRs in atmospheric particulate matter and typical gaseous pollutants. 展开更多
关键词 particulate matter(PM) environmentally persistent free radicals(EPFRs) formation mechanism influencing factors
下载PDF
谈谈图书馆的“读书会” 被引量:3
16
作者 徐英 孙秉良 钱培生 《图书馆建设》 1982年第4期17-20,共4页
“读书会”顾名思义就是组织读者共同读几本书籍,并围绕书中所讲的几个有探讨价值,带有普遍意义的问题展开讨论或与心得体会,评论文章,从而促进人们集思广益,互相交流,共同提高。它是一种陶冶青年一代文化素养和高尚情操,使读者进行自... “读书会”顾名思义就是组织读者共同读几本书籍,并围绕书中所讲的几个有探讨价值,带有普遍意义的问题展开讨论或与心得体会,评论文章,从而促进人们集思广益,互相交流,共同提高。它是一种陶冶青年一代文化素养和高尚情操,使读者进行自我教育的有效的方式。 展开更多
关键词 读书会 图书馆工作 书评 上海图书馆 青年读者 书籍 大读者 教商 响影 大青年
下载PDF
Distribution of Rapeseed Clubroot Disease in Hubei Province and Evaluation of Yield Loss 被引量:6
17
作者 任莉 贾建光 +5 位作者 李铭 刘凡 程雨贵 张明海 陈坤荣 方小平 《Agricultural Science & Technology》 CAS 2012年第4期775-777,F0003,共4页
[Objective] The aim of this study was to reveal the distribution of rapeseed clubfoot disease in Hubei Province and to assess the yield loss caused by the pathogen, Plasmodiophora brassicae. [Method] Field surveys wer... [Objective] The aim of this study was to reveal the distribution of rapeseed clubfoot disease in Hubei Province and to assess the yield loss caused by the pathogen, Plasmodiophora brassicae. [Method] Field surveys were conducted in Shayang, Dangyang, Zhijiang, Yidu and Changyang of Hubei Province during 2009- 2011. Clubfoot disease of rapeseed samples from the surveyed locations were con- firmed by PCR detection and plants infection experiment. The factors of yield and plot yields influenced by clubroot disease were determined in plot experiment. [Re- salt] Rapeseed clubroots were confirmed in Zhijiang and Dangyang and not found in Shayang and Yidu. Clubroot was found in cruciferous vegetables but not in rapeseed d in Changyang. Infection of P. brassicae significantly decreased of the first effective branch numbers of rapeseed, effective pod number per plant, seed number per pod and 1 000-grain weight. Yield of infected rapeseed decreased by 56.4% over non-infected control. [Conclusion] Rapeseed clubroot disease mainly distributed in Zhijiang and Dangyang of Hubei Province. The disease had an economic impact on rapeseed production. 展开更多
关键词 Brassica napus Plasmodiophora brassicae Occurence Economic impact
下载PDF
Possible Impacts of Climate Change on Agricultural Production in China and Its Adaptation Countermeasures 被引量:10
18
作者 袁彬 郭建平 +1 位作者 赵俊芳 冶明珠 《Agricultural Science & Technology》 CAS 2011年第3期420-425,共6页
Global climate warming has discernable impacts on various natural systems and biological systems. As the most fragile ecosystem,agriculture is subjected to the most direct impacts from climate change. Of these impacts... Global climate warming has discernable impacts on various natural systems and biological systems. As the most fragile ecosystem,agriculture is subjected to the most direct impacts from climate change. Of these impacts,the first one is the change in agricultural climate resources,which directly affects agricultural cultivation structure and crop variety distribution and finally results in the change in crop yield. Here,we review the advances in the impacts of climate change on crop yield,agricultural climate resources and China's agricultural cropping system and crop variety distribution pattern,and prospect the countermeasures for agricultural production in order to meet the future climate change,and several issues must be given high priority. 展开更多
关键词 Climate change Agricultural production Impact Adaptation countermeasure
下载PDF
Temporal-spatial Changes in Inner Mongolian Grassland Degradation during Past Three Decades 被引量:10
19
作者 张清雨 吴绍洪 +1 位作者 赵东升 戴尔阜 《Agricultural Science & Technology》 CAS 2013年第4期676-683,共8页
[Objective] This study aimed to analyze the temporal-spatial variation of Inner Mongolian grassland degradation during past three decades. [Method] The dis- tribution characteristics of grassland were described by lan... [Objective] This study aimed to analyze the temporal-spatial variation of Inner Mongolian grassland degradation during past three decades. [Method] The dis- tribution characteristics of grassland were described by land use types supervised classification with TM/ETM. Then, temporal-spatial changes of grassland coverage were quantified by the mean of maximum vegetation coverage in last 30 years. Lastly, the grassland degradation reasons were explored through statistic analysis between the grassland coverage and precipitation, temperature and grazing intensity. [Result] The grassland degradation index of Inner Mongolia was increased from 1.38 to 1.68, and the smallest was 1.28 in 2005s. Grassland degradation and improve- ment were concurrent after 1980s, but grassland degradation was the major change trend for Inner Mongolia grassland. The area of grassland degradation was enlarged from 18.08×10^4 km2 in 1980s to 22.47×10^4 km2 in 2010s on the whole and distribu- tion range was shifted from central-eastern to west in Inner Mongolia that mainly distributed on Hulun Buir and Xilin Gol grassland in 1980s and Ordos and Alax grassland in 2010s. The grassland area of degradation had a rising trend form 1980s to 1995s, then reduced to 10.8x104 km2 in 2005s, and decreased in 2010s, which mainly speared in the west of Xilin Gol grassland. [Conclusion] Inner Mongo-lian grassland degradation were become more seriously in last 30 years because that temperature, precipitation and graze intensities change, which not performance on decreasing coverage but grassland areas. 展开更多
关键词 Grassland degradation Temporal-spatial change Influencing factor Inner Mongolia
下载PDF
Microthermokinetic study of xanthate adsorption on impurity-doped galena 被引量:9
20
作者 蓝丽红 陈建华 +3 位作者 李玉琼 蓝平 杨卓 艾光湧 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第1期272-281,共10页
Six kinds of galena with different impurities were synthesized and the effects of impurities on the floatability of galena were investigated. The thermodynamic and kinetic parameters on the galena surface were measure... Six kinds of galena with different impurities were synthesized and the effects of impurities on the floatability of galena were investigated. The thermodynamic and kinetic parameters on the galena surface were measured using microcalorimetry, and the adsorption configuration and energy of butyl xanthate on the surfaces of galena with different impurities were simulated by density functional theory. Flotation experiments showed that Ag and Bi significantly promoted the recovery of galena, while Zn, Sb, Mn, and Cu reduced the recovery of the flotation. Microthermokinetic results indicated that the absolute value of xanthate adsorption heat was directly proportional to the flotation recovery of galena. Adsorption heat and reaction rate coefficients of xanthate on galena containing Ag or Bi were larger than those on pure galena, but smaller on galena containing Cu or Sb. Additionally, the relationship between the heat of unsaturated adsorption of xanthate and the adsorption energy of impurity atom on galena surface was investigated. 展开更多
关键词 GALENA impurity effect floatation XANTHATE ADSORPTION MICROCALORIMETRY density functional theory
下载PDF
上一页 1 2 59 下一页 到第
使用帮助 返回顶部