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The abundance,distribution,and enrichment mechanism of harmful trace elements in coals from Guizhou,Southwestern China
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作者 Hui Hou Wei Cheng +1 位作者 Ruidong Yang Yan Zhang 《Acta Geochimica》 EI CAS CSCD 2024年第5期889-903,共15页
Coal seams can enrich a variety of harmful trace elements under specific geological conditions.The spatial distribution of harmful trace elements in coal is extremely uneven,and the distribution characteristics of eac... Coal seams can enrich a variety of harmful trace elements under specific geological conditions.The spatial distribution of harmful trace elements in coal is extremely uneven,and the distribution characteristics of each element content are different.The harmful elements released in the process of coal mining and utilization will cause serious harm to the environment and the human body.It is of great resource significance to study the geochemistry of coal that affects the enrichment and distribution characteristics of harmful trace elements.Based on the domestic and foreign literature on coal geochemistry in Guizhou published by previous investigators,this study counted 1097 sample data from 23 major coal-producing counties in Guizhou Province,systematically summarized the relevant research results of harmful trace elements in the coal of Guizhou,and revealed the overall distribution and enrichment characteristics of harmful trace elements in the coal of Guizhou.The results show that the average contents of Cd,Pb,Se,Cu,Mo,U,V,As,Hg,and Cr in coal of Guizhou are higher than those in Chinese coal and world coal.A variety of harmful trace elements in the coal of Guizhou have high background values,especially in Liupanshui,Xingyi and Qianbei coalfield.The enrichment of various harmful trace elements in the Late Permian coal in Guizhou is mainly related to the combined action of various geological and geochemical factors.The supply of terrigenous debris and sedimentary environment may be the basic background of the enrichment of harmful elements in western Guizhou,while low-temperature hydrothermal activity and volcanic ash deposition may be the main reasons for the enrichment of harmful elements in southwestern Guizhou. 展开更多
关键词 harmful trace elements Distribution characteristics Enrichment law Geological and geochemical features GUIZHOU
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Determination of Total Flavonoids in Acanthopanax senticosus(Rupr. et Maxim.) Harms by Enzymolysis and Its Technological Optimization
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作者 Li Xinzhi Wang Yudan +4 位作者 Wang Meiliang Liu Tianyang Gao Ruihua Qiu Youwen Zhang Shunjie 《Journal of Northeast Agricultural University(English Edition)》 CAS 2024年第1期53-60,共8页
In order to optimize the ultrasonic extraction technique for the total flavonoid of leaf yellows plus, the contents of 21 leaf yellows plus total flavonoid from four regions in Heilongjiang Province were comparatively... In order to optimize the ultrasonic extraction technique for the total flavonoid of leaf yellows plus, the contents of 21 leaf yellows plus total flavonoid from four regions in Heilongjiang Province were comparatively analyzed. The ultrasonic extraction technology was optimized by Box-Behnken response surface method, and the total flavonoid content of 21 kinds of Acanthopanax senticosus(Rupr. et Maxim.) Harms from different producing areas were analyzed by cluster analysis. The optimal process conditions were determined as ultrasonic time 30 min, solid-liquid ratio 1 : 12 and ultrasonic power 250 W, and the average yield of the total flavonoid was 1.453 mg·g^ (-1). By optimizing the ultrasonic-assisted extraction method, the total flavonoid content from different producing areas was compared in the experiment, which provided certain data support for the optimization of the extraction process in the future and laid a certain theoretical foundation for the quality analysis of Chinese medicinal materials. 展开更多
关键词 Acanthopanax senticosus(Rupr.et Maxim.)harms total flavonoid Box-Behnken response surface test ultrasonic-assisted extraction
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Harm of Hail to Crops and Countermeasures of Artificial Hail Suppression in Ulanqab City
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作者 Pei WANG Tengge'er WU Jinhua LIU 《Meteorological and Environmental Research》 2024年第2期62-63,70,共3页
Hail is one of meteorological disasters affecting crop growth in Ulanqab City.It happens frequently from May to September,and this period is also the main growing season of crops.In this period,hail will cause damage ... Hail is one of meteorological disasters affecting crop growth in Ulanqab City.It happens frequently from May to September,and this period is also the main growing season of crops.In this period,hail will cause damage to crops,make farmland soil harden,and bring varying degrees of harm to agricultural production.Artificial hail suppression is an important scientific and technological means for disaster prevention and mitigation.It is necessary to strengthen the monitoring,analysis and forecast of severe convection weather,intensify the release of early warning information of hail weather,provide accurate and reliable real-time information for the implementation of artificial hail suppression operations,strengthen the implementation of artificial weather modification,effectively carry out artificial hail suppression operations,and avoid and reduce the impact of hail disaster. 展开更多
关键词 HAIL CROPS harm Artificial hail suppression Ulanqab City
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Factors inducing morphological transition in harmful algal bloom-forming species Phaeocystis globosa with emphasis on predator chemical cue
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作者 Xiao YANG Pingping SHEN Ke LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第4期1537-1546,共10页
The microalga Phaeocystis globosa is recognized as a harmful alga and also one of the few keystone phytoplankton genera that shape the structure and function of marine ecosystems.P.globosa possess a complex polymorphi... The microalga Phaeocystis globosa is recognized as a harmful alga and also one of the few keystone phytoplankton genera that shape the structure and function of marine ecosystems.P.globosa possess a complex polymorphic life cycle,exhibiting phase alternation between free-living cells of approximately 3-6μm in diameter and gelatinous colonies(palmelloid stage)reaching several millimeters.The knowledge on the factors that induced the morphological transition of P.globosa in the last two decades was reviewed.Emphasis is given to infochemicals,an additional biological factor induced by predator,with the attempt to reveal a relevant mechanism of induced morphological defense. 展开更多
关键词 Phaeocystis globosa POLYMORPHISMS harmful algal blooms defense strategies INFOCHEMICAL
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Benefits and harms of screening for hepatocellular carcinoma in high-risk populations: systematic review and meta-analysis
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作者 Jichun Yang Zhirong Yang +4 位作者 Xueyang Zeng Shuqing Yu Le Gao Yu Jiang Feng Sun 《Journal of the National Cancer Center》 2023年第3期175-185,共11页
Objective:The incidence and mortality of hepatocellular carcinoma(HCC)have been increasing around the world.Current guidelines recommend HCC screening in high-risk population.However,the strength of evidence of ben-ef... Objective:The incidence and mortality of hepatocellular carcinoma(HCC)have been increasing around the world.Current guidelines recommend HCC screening in high-risk population.However,the strength of evidence of ben-efits and harms of HCC screening to support the recommendation was unclear.The objective is to systematically synthesize current evidence on the benefits and harms of HCC screening.Methods:We searched PubMed and nine other databases until August 20,2021.We included cohort studies and RCTs that compared the benefits and harms of screening and non-screening in high-risk population of HCC.Case series studies that reported harms of HCC screening were also included.Pooled risk ratio(RR),according to HCC screening status,was calculated for each benefit outcome(e.g.,HCC mortality,survival rate,proportion of early HCC),using head-to-head meta-analysis.The harmful outcomes(e.g.,proportion of physiological harms provided by non-comparative studies were pooled by prevalence of meta-analysis).Analysis on publication bias and quality of life,subgroup analysis,and sensitivity analysis were also conducted.Results:We included 70 studies,including four random clinical trials(RCTs),63 cohort studies,three case se-ries studies.The meta-analysis of RCTs showed HCC screening was significantly associated with reduced HCC mortality(RR[risk ratio],0.73[95%CI,0.56-0.96];I^(2)=75.1%),prolonged overall survival rates(1-year,RR,1.72[95%CI,1.13-2.61];I^(2)=72.5%;3-year,RR,2.86[95%CI,1.78-4.58];I^(2)=10.1%;and 5-year,RR,2.76[95%CI,1.37-5.54];I^(2)=28.3%),increased proportion of early HCC detection(RR,2.68[95%CI,1.77-4.06];I^(2)=50.4%).Similarly,meta-analysis of cohort studies indicated HCC screening was more effective than non-screening.However,pooled proportion of physiological harms was 16.30%(95%CI:8.92%-23.67%)and most harms were of a mild to moderate severity.Conclusion:The existing evidence suggests HCC screening is more effective than non-screening in high-risk pop-ulation.However,harms of screening should not be ignored. 展开更多
关键词 Hepatocellular carcinoma SCREENING BENEFITS harmS META-ANALYSIS
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Changes of Water Temperature and Harmful Algal Bloom in the Daya Bay in the Northern South China Sea 被引量:7
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作者 余景 唐丹玲 +2 位作者 王素芬 练建生 王友绍 《Marine Science Bulletin》 CAS 2007年第2期25-33,共9页
Economic development around the Daya Bay, China has profoundly affected the marine environment in the bay area in recent years, particularly since the operation of Daya Bay Nuclear Power Station (DNPS) in 1994. This... Economic development around the Daya Bay, China has profoundly affected the marine environment in the bay area in recent years, particularly since the operation of Daya Bay Nuclear Power Station (DNPS) in 1994. This study analyzed the changes of water temperature and harmful algal blooms (HABs) for two periods: 1983-1993 and 1994-2004, using in situ and satellite data. Results showed that yearly mean surface water temperature (SWT) and Chl-a concentration (Chl-a) increased by 1.1 ℃ and 1.9 mg/m^3, respectively, after 1994. The monthly occurrence of HAB was found to have increased also. HABs appeared only in spring and autumn before 1994, but occurred all the year round after 1994. SWT, Chl-a and HABs all increased significantly in May. Those changes were associated with environmental changes in this area, such as thermal discharge from the DNPS and enhancement of eutrophication from human activities around the Daya Bay. 展开更多
关键词 water temperature harmful Algal Bloom Chlorophyll a nuclear power station Daya Bay China
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Fluorescence-assisted Image Analysis of Harmful Microalgae 被引量:1
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作者 王学民 孙勇 曹红宝 《Marine Science Bulletin》 CAS 2006年第1期75-82,共8页
In order to realize the detection and analysis of microalgae in sediment samples with complex scenes, the project takes advantage of the character of microalgae that they can auto-fluoresce when exposed to the illumin... In order to realize the detection and analysis of microalgae in sediment samples with complex scenes, the project takes advantage of the character of microalgae that they can auto-fluoresce when exposed to the illumination of certain exciation waves. The project takes grey-scale and fluorescent pictures of microalgae in the same field of view and uses the image processing technique to deal with the images, such as threshold segmentation, contour and texture analysis and pattern recognition. The results show that the fluorescent image can effectively elimate the yawp in the complex background and make the consequent image processing more effective and easy. Then the project comes to the conclusion that fluorescence-assisted image processing can realize the detection and analysis of microalgae in sediment samples containing complex scenes. 展开更多
关键词 harmful microalgae image segmentation FLUORESCENCE
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The Impact of Fitness between Consumers and Product-harm Crisis on the Online Dysfunctional Customer Behavior 被引量:1
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作者 Huichao LI Jiaojiao FENG Jun WANG 《Asian Agricultural Research》 2014年第5期22-26,30,共6页
With the popularization of the Internet,this technology has changed the form of information dissemination. The information will spread quickly when food product harm crisis happens,and the phenomenon that information ... With the popularization of the Internet,this technology has changed the form of information dissemination. The information will spread quickly when food product harm crisis happens,and the phenomenon that information of product-harm spills over is very common. This article is based on " Frustration- Misbehaving" research paradigm,combined with the information dissemination motivation theory,discusses that the fitness between the consumers and the crisis will promote consumers' dysfunctional customer behavior. The study found that the fitness between the consumers and the crisis has significant effect on consumers' dysfunctional customer behavior,perceived social damage has a mediator effect between fitness and consumers' misbehavior,and the moderating effect of consumers' aggression tendency is significant,but not the emotional tendency. The theoretical contribution and valuable implications of findings for communication of crisis management are discussed at last. 展开更多
关键词 Product-harm CRISIS FITNESS PERCEIVED social harm
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Investigation on the Harm of Wild Boar in Mingtong Town, Chengkou, Chongqing
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作者 王正春 张后伟 吴旭 《Agricultural Science & Technology》 CAS 2017年第12期2446-2449,共4页
Through the investigation and analysis of the wild boars in Mingtong Town, Chengkou, Chongqing, it was concluded that the area had long been seri- ously affected by wild boars and some of the human activities were pot... Through the investigation and analysis of the wild boars in Mingtong Town, Chengkou, Chongqing, it was concluded that the area had long been seri- ously affected by wild boars and some of the human activities were potentially threatened, and the potential threat areas were identified. Corresponding suggestions were proposed to guide the prevention and control work, so as to protect the habi- tat and reproduction of wildlife and ensure the normal production and life of the masses. 展开更多
关键词 Wild boar harm THREAT Prevention and control
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基于PRISMA Harms清单的中医药安全性系统综述现状及报告质量分析 被引量:3
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作者 胡瑞学 文玲子 +13 位作者 于明坤 任毅铭 曹卉娟 高佳琪 刘可心 赵璐明 李一琳 林子宜 张子萱 明扬 武雪岑 李迅 刘建平 费宇彤 《中国药物警戒》 2019年第4期231-238,共8页
目的了解中医药安全性系统综述的报告现状,加强对中医药安全性的认识,以提高中医药安全性系统综述的报告质量。方法通过计算机检索中国知网(CNKI)、万方(Wan Fang Data)、维普(VIP)三大中文数据库中关于中医药安全性的系统综述,对纳入... 目的了解中医药安全性系统综述的报告现状,加强对中医药安全性的认识,以提高中医药安全性系统综述的报告质量。方法通过计算机检索中国知网(CNKI)、万方(Wan Fang Data)、维普(VIP)三大中文数据库中关于中医药安全性的系统综述,对纳入文献的特征进行描述并依据PRISMA Harms清单对文献对应的条目进行评价,提出改进中医药安全性系统综述报告质量的建议。结果研究最终纳入文献共116篇,发表的时间跨度为2000~2018年,文献发表数量相对较少,年发表中医药安全性系统综述的数量在逐渐上升。口服中药的安全性系统综述有69篇(59.48%),中药注射剂20篇(17.24%)。关注心血管相关疾病和中风相关疾病较多,各有14篇(12.07%)。纳入文献类型以仅纳入随机对照试验为主(63.79%)。文献质量评价主要采用Cochrane偏倚风险评价工具(57.76%)。仅有2篇文献的报告条目在25个以上。结论中医药安全性系统综述数量较少但年发表数量逐渐增多。虽然纳入的文献报告条目大多数都有涉及,但整体报告质量有待提高。应重视安全性系统综述内容的规范撰写,同时建议期刊能够依据PRISMA Harms清单进一步规范安全性系统综述的要求。 展开更多
关键词 PRISMAharms 中医药 系统综述 安全性 报告质量
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Effects of temperature, salinity, and irradiance on the growth of harmful algal bloom species Phaeocystis globosa Scherffel(Prymnesiophyceae) isolated from the South China Sea 被引量:11
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作者 徐宁 黄博珠 +3 位作者 胡章喜 唐赢中 段舜山 张成武 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第3期557-565,共9页
Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal ... Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal waters that facilitate its rapid expansion, the effects of temperature, salinity and irradiance on the growth of P. globosa from the South China Sea were examined in the laboratory. The saturating irradiance for the growth ofP. globosa (Is) was 60 μmol/(m^2·s), which was lower than those of other harmful algal species (70-114μmol/(m^2·s)). A moderate growth rate of 0.22/d was observed at 2 μmol/(m^2·s) (the minimum irradiance in the experiment), and photo-inhibition did not occur at 230 μmol/(m^2·s) (the maximum irradiance in the experiment). Exposed to 42 different combinations of temperatures (10- 31 ℃) and salinities (10-40) under saturating irradiance, P. globosa exhibited its maximum specific growth rate of 0.80/d at the combinations of 24℃ and 35, and 27℃ and 40. The optimum growth rates (〉0.80/d) were observed at temperatures ranging from 24 to 27℃ and salinities from 35 to 40. While P. globosa was able to grow well at temperatures from 20℃ to 31℃ and salinities from 20 to 40, it could not grow at temperatures lower than 15℃ or salinities lower than 15. Factorial analysis revealed that temperature and salinity has similar influences on the growth of this species. This strain ofP. globosa not only prefers higher temperatures and higher salinity, but also possesses a flexible nutrient competing strategy, adapted to lower irradiance. Therefore, the P. globosa population from South China Sea should belong to a new ecotype. There is also a potentially high risk of blooms developing in this area throughout the year. 展开更多
关键词 Phaeocystis globosa harmful algal bloom TEMPERATURE SALINITY IRRADIANCE GROWTH
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Supercritical Fluid Extraction of Total Flavonoids from Leaves of Acanthopanax Senticosus Harms 被引量:13
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作者 LIU Chun-ming ZHAO Ji-min +1 位作者 LI Hong-mei SONG Feng-rui 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第2期233-236,共4页
The herbal plant Acanthopanax Senticosus Harms is natural herb of Changbaishan in Jilin Province of China, which belongs to the Araliaceae family. As the ingredients of folk medicine, it has long been used to treat a ... The herbal plant Acanthopanax Senticosus Harms is natural herb of Changbaishan in Jilin Province of China, which belongs to the Araliaceae family. As the ingredients of folk medicine, it has long been used to treat a variety of human diseases, such as cerebrovascular disease, diabetes, tumor, isochemic heart diseases, hypertension, rheumatic arthritis, etc. E2,33. Flavonoids, a class of constituent compounds, which have a broad distribution in the nature and are found in Acanthopanax Senticosus Harms, have gained particular attention. A number of studies have shown that flavonoid compounds have wide biological activities, such as anti-aging, anticancer, anti-HIV, 展开更多
关键词 Supercritical fluid extraction(SFE) Acarahopanax Senticosus harms FLAVONOIDS
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Distribution Characteristics of Sulfur and the Main Harmful Trace Elements in China's Coal 被引量:5
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作者 TANG Shuheng SUN Shenglin +2 位作者 QIN Yong JIANG Yaofa WANG Wenfeng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第3期722-730,共9页
To promote the rational development and use of clean coal resources in China, data on the regional and age distribution of sulfur, arsenic and other harmful elements in Chinese coal was broadly collected, tested for c... To promote the rational development and use of clean coal resources in China, data on the regional and age distribution of sulfur, arsenic and other harmful elements in Chinese coal was broadly collected, tested for content, and analyzed. Coal in northwestern China is characterized by low to extremely low levels of sulfur; the coal of the Taiyuan Formation in northern China mainly has high-sulfur content; that of the Shanxi Formation is mainly characterized by low sulfur coal; and the Late Permian coal in southern China has overall higher sulfur content; other regions have low sulfur coal. The average content of harmful trace elements in the bulk of China's coal is similar to the corresponding content in the coal of the North America and the rest of the world, whereas the content of various elements (Hg, Sb and Se) is different in magnitude to the corresponding percentage in the crust. The average content of the elements Cr, Se, Co, Be, U, Br in Late Permian coal in S China ranks first in the country whereas the average content of Hg and CI in the coals of Late Carboniferous to Early Permian age in N China are the highest. The average content of Mn in Early and Middle Jurassic coal is higher in NW China. The high content of harmful elements in some coal should cause particular concern both in the development and utilization of coal. 展开更多
关键词 COAL SULFUR harmful trace elements distribution patterns ENVIRONMENT China
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Spatio-temporal variations of harmful algal blooms along the coast of Guangdong,Southern China during 1980–2016 被引量:4
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作者 LI Li Lü Songhui CEN Jingyi 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2019年第2期535-551,共17页
Harmful algal blooms (HABs) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system (GIS) ... Harmful algal blooms (HABs) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system (GIS) was utilized to determine spatial and temporal characteristics of HAB events in the coastal waters of Guangdong from 1980–2016. We analyzed distribution patterns and characteristics of HABs by dividing the coast of Guangdong into well-known bays, estuary and coastal waters. Results showed that there were a total of 337 HABs recorded in Guangdong coastal waters. Spatial and temporal distributions varied among diff erent regions. Most HABs occurred in the Mirs Bay, followed by the west coast of Daya Bay, while a few occurred in the west and east coasts of Guangdong but with an increasing trend in the past two decades. HABs occurred mostly in warmer months of March to May in the western coast of Guangdong, March and April in Mirs Bay, April in Zhujiang (Pearl) River estuary, November in eastern coast of Guangdong. For Daya Bay, most HABs were reported between March and September. The most frequently occurring HABs species were Noctiluca scintillans , Phaeocystis globosa , Skeletonema costatum and Scrippsiella trochoidea , occurring mostly in Mirs Bay, western Guangdong coast area, eastern Guangdong coast area and Zhujiang River estuary and Daya Bay, respectively. Ichthyotoxic blooms were more common than toxic blooms, and Heterosigma akashiwo , Chattonella marina , Karenia mikimotoi and P haeocystis globosa were the most common ichthyotoxic species. Our results provide baseline information useful for policy making and management of HABs in the region. 展开更多
关键词 harmful ALGAL BLOOMS GUANGDONG Province distribution GEOGRAPHIC information system (GIS) KERNEL density estimation
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Benefits and harms of endoscopic screening for gastric cancer 被引量:10
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作者 Chisato Hamashima 《World Journal of Gastroenterology》 SCIE CAS 2016年第28期6385-6392,共8页
Gastric cancer has remained a serious burden worldwide, particularly in East Asian countries. However, nationwide prevention and screening programs for gastric cancer have not yet been established in most countries ex... Gastric cancer has remained a serious burden worldwide, particularly in East Asian countries. However, nationwide prevention and screening programs for gastric cancer have not yet been established in most countries except in South Korea and Japan. Although evidence regarding the effectiveness of endoscopic screening for gastric cancer has been increasingly accumulated, such evidence remains weak because it is based on results from studies other than randomized controlled trials. Specifically, evidence was mostly based on the results of cohort and case-control studies mainly conducted in South Korea and Japan. However, the consistent positive results from these studies suggest promising evidence of mortality reduction from gastric cancer by endoscopic screening. The major harms of endoscopic screening include infection, adverse effects, false-positive results, and overdiagnosis. Despite the possible harms of endoscopic screening, information regarding these harms remains insufficient. To provide appropriate cancer screening, a balance of benefits and harms should always be considered when cancer screening is introduced as a public policy. Quality assurance is very important for the implementation of cancer screening to provide high-quality and safe screening and minimize harms. Endoscopic screening for gastric cancer has shown promising results, and thus deserves further evaluation to reliably establish its effectiveness and optimal use. 展开更多
关键词 Gastric cancer Cancer screening Upper gastrointestinal endoscopy Mortality reduction Cohort study Case-control study harmS
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Analysis of the Harmfulness of Water-Inrush from Coal Seam Floor Based on Seepage Instability Theory 被引量:19
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作者 KONG Hai-ling MIAO Xie-xing +2 位作者 WANG Lu-zhen ZHANG Yu CHEN Zhan-qing 《Journal of China University of Mining and Technology》 EI 2007年第4期453-458,共6页
A theory of seepage instability was used to estimate the harmfulness of water-inrush from a coal seam floor in a particular coal mine of the Mining Group,Xuzhou. Based on the stratum column chart in this coal mine,the... A theory of seepage instability was used to estimate the harmfulness of water-inrush from a coal seam floor in a particular coal mine of the Mining Group,Xuzhou. Based on the stratum column chart in this coal mine,the distribu-tion of stress in mining floors when the long-wall mining was respectively pushed along to 100 m and to 150 m was simulated by using the numerical software (RFPA2D). The permeability parameters of the coal seam floor are described given the relationship between permeability parameters. Strain and the water-inrush-indices were calculated. The wa-ter-inrush-index was 67.2% when the working face was pushed to 100 m,showing that water-inrush is possible and it was 1630% when the working face was pushed to 150 m,showing that water-inrush is quite probable. The results show that as long-wall mining is pushed along,the failure zone is enlarged,the strain increased,and fissures developed cor-respondingly,resulting in the formation of water-inrush channels. Accompanied by the failure of the strata,the perme-ability increased exponentially. In contrast,the non-Darcy flow β factor and the acceleration coefficient decreased ex-ponentially,while the increase in the water-inrush-index was nearly exponential and the harmfulness of water-inrush in the coal mine increased accordingly. 展开更多
关键词 coal seam floor harm of water-inrush water-inrush-index seepage instability rock strata
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Effects of ambient DIN:DIP ratio on the nitrogen uptake of harmful dinoflagellate Prorocentrum minimum and Prorocentrum donghaiense in turbidistat 被引量:6
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作者 李纪 Patricia M. GLIBERT Jeffrey A. ALEXANDER 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第4期746-761,共16页
The effects of varying nitrogen (N): phosphorus (P) ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat... The effects of varying nitrogen (N): phosphorus (P) ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N:P ratios. Experiments to determine rates of N uptake and assimilation of different N sources (NO^3-, NH4^+, urea and glycine by P. minimum and NO3^-, NH4^+ by P. donghaiense) were conducted using ^15-N tracer techniques at each N:P ratio. The growth rates suggested nutrient limitation at both high and low N:P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium (low N:P ratio), both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N:P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^+ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N:P ratio of 12 for both species. The N uptake rates of cultures at N:P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N:P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems. 展开更多
关键词 harmful dinoflagellate N:P ratio nitrogen uptake continuous culture Prorocentrum spp
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Effects of irradiance on pigment signatures of harmful algae during growth process 被引量:3
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作者 LIU Shuxia YU Zhigang YAO Peng ZHENG Yan LI Dong 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2011年第6期46-57,共12页
Three harmful algal bloom (HAB) species, Phaeocystis globosa, Thalassiosira rotula, and Prorocentrum donghaiense were isolated from the coast of China and cultured in batches at three light intensities (40, 70 and ... Three harmful algal bloom (HAB) species, Phaeocystis globosa, Thalassiosira rotula, and Prorocentrum donghaiense were isolated from the coast of China and cultured in batches at three light intensities (40, 70 and 150 μmol photons · m -2 · s -1 ). The variation patterns of cell numbers and growth rates with light intensity during growth process were different among species. In P. globosa and T. rotula, maximum growth rates were found at 150 μmol photons · m -2 · s -1 and ranged from 0.60 divisions per day in T. rotula, to 1.17 divisions per day in P. globosa. The highest growth rate of P. donghaiense, however, was found at 70 μmol photons · m -2 · s -1 (0.36 divisions per day). In general, all the three HAB species showed adaptation to increasing light intensity by decreasing cellular concentrations of chlorophyll a (Chl a), but the variation patterns during the growth process were species-specific. The cellular concentrations of Chl a in P. donghaiense and T. rotula increased gradually with incubation time, but the opposite trend was found in P. globosa. Most of the pigment ratios and pigment indices of these three species were nearly constant during the growth process and showed small changes at different light intensities illustrating the applicability of chemotaxonomy during the initial and developing stages of HAB events, which is very important to study the ecological issues related to HAB species. Ratios of photoprotective carotenoids, such as diadinoxanthin, diatoxanthin and β, β-carotene to total chlorophylls a (Tchl a) showed the trend of increasing with the increase of light intensity during growth process. The species-specific and pigment-specific variations in pigment ratios/indices at different light intensities during growth process probably reflected the differences in the pigment composition as well as the adaption capabilities of different species to the changes of physical conditions. 展开更多
关键词 harmful algal bloom light intensity growth rate pigment ratio pigment index cellular concentration
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High resolution crop intensity mapping using harmonized Landsat-8 and Sentinel-2 data 被引量:5
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作者 HAO Peng-yu TANG Hua-jun +2 位作者 CHEN Zhong-xin YU Le WU Ming-quan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2019年第12期2883-2897,共15页
An increase in crop intensity could improve crop yield but may also lead to a series of environmental problems, such as depletion of ground water and increased soil salinity. The generation of high resolution(30 m) cr... An increase in crop intensity could improve crop yield but may also lead to a series of environmental problems, such as depletion of ground water and increased soil salinity. The generation of high resolution(30 m) crop intensity maps is an important method used to monitor these changes, but this is challenging because the temporal resolution of the 30-m image time series is low due to the long satellite revisit period and high cloud coverage. The recently launched Sentinel-2 satellite could provide optical images at 10–60 m resolution and thus improve the temporal resolution of the 30-m image time series. This study used harmonized Landsat Sentinel-2(HLS) data to identify crop intensity. The sixth polynomial function was used to fit the normalized difference vegetation index(NDVI) and enhanced vegetation index(EVI) curves. Then, 15-day NDVI and EVI time series were then generated from the fitted curves and used to generate the extent of croplands. Lastly, the first derivative of the fitted VI curves were used to calculate the VI peaks;spurious peaks were removed using artificially defined thresholds and crop intensity was generated by counting the number of remaining VI peaks. The proposed methods were tested in four study regions, with results showing that 15-day time series generated from the fitted curves could accurately identify cropland extent. Overall accuracy of cropland identification was higher than 95%. In addition, both the harmonized NDVI and EVI time series identified crop intensity accurately as the overall accuracies, producer’s accuracies and user’s accuracies of non-cropland, single crop cycle and double crop cycle were higher than 85%. NDVI outperformed EVI as identifying double crop cycle fields more accurately. 展开更多
关键词 CROP inten sity time series sixth polyno mial FU nction harm on ized LAN dsat-8 and Sen tinel-2
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Potentially harmful metals,and health risk evaluation in groundwater of Mardan,Pakistan:Application of geostatistical approach and geographic information system 被引量:4
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作者 Abdur Rashid Muhammad Ayub +7 位作者 Asif Javed Sardar Khan Xubo Gao Chengcheng Li Zahid Ullah Tariq Sardar Juma Muhammad Shahla Nazneen 《Geoscience Frontiers》 SCIE CAS CSCD 2021年第3期597-608,共12页
This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,... This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe in the groundwater samples.Moreover,geographic information system(GIS),XLSTAT,and IBM SPSS Statistics 20 software were used for spatial distribution modeling,principal component analysis(PCA),cluster analysis(CA),and Quantile-Quantile(Q-Q)plotting to determine groundwater pollution sources,similarity index,and normal distribution reference line for the selected parameters.The mean values of pH,TDS,elevation,ORP,temperature,depth,and Br were 7.2,322 mg/L,364 m,188 mV,29.6℃,70 m,0.20 mg/L,and PHMs like Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe were 0.38,0.26,0.08,0.27,0.36,0.22,0.04,0.43 and 0.86 mg/L,respectively.PHMs including Cr(89%),Cd(43%),Mn(23%),Pb(79%),Co(20%),and Fe(91%)exceeded the guideline values set by the world health organization(WHO).The significant R^(2)values of PCA for selected parameters were also determined(0.62,0.67,0.78,0.73,0.60,0.87,-0.50,0.69,0.70,0.74,-0.50,0.70,0.67,0.79,0.59,and-0.55,respectively).PCA revealed three geochemical processes such as geogenic,anthropogenic,and reducing conditions.The mineral phases of Cd(OH)_(2),Fe(OH)_(3),FeOOH,Mn_(3)O_(4),Fe_(2)O_(3),MnOOH,Pb(OH)_(2),Mn(OH)_(2),MnO_(2),and Zn(OH)_(2)(-3.7,3.75,9.7,-5.8,8.9,-3.6,2.2,-4.6,-7.7,-0.9,and 0.003,respectively)showed super-saturation and under-saturation conditions.Health risk assessment(HRA)values for PHMs were also calculated and the values of hazard quotient(HQ),and hazard indices(HI)for the entire study area were increased in the following order:Cd>Ni>Cu>Pb>Mn>Zn>Cr.Relatively higher HQ and HI values of Ni,Cd,Pb,and Cu were greater than one showing unsuitability of groundwater for domestic,agriculture,and drinking purposes.The long-term ingestion of groundwater could also cause severe health concerns such as kidney,brain dysfunction,liver,stomach problems,and even cancer. 展开更多
关键词 GROUNDWATER Potential harmful metals Health risk indices Cluster analysis Mineral phases
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