检索结果-南通市图书馆

Chemical Characteristics of Carbonaceous Aerosols During Dust Storms over Xi'an in China

Advances in Atmospheric Sciences 2008年第5期25卷 847-855页

作者：李旭祥曹军骥 judith CHOW 韩永明李顺诚 John WATSON Department of Environmental Science and Technology Xi'an Jiaotong University Desert Research Institute Reno NV USA State Key Lab of Loess & Quaternary Geology Institute of Earth EnvironmentChinese Academy of Sciences The Hong Kong Polytechnic University

Characterization of carbonaceous aerosols including CC （carbonate carbon）, OC （organic carbon）, and EC （elemental carbon） were investigated at Xi＇an, China, near Asian dust source regions in spring 2002. OC varied between 8.2 and 63.7μgm^- 3, while EC ranged between 2.4 and 17.2 μ m^-3 during the observation period. OC variations followed a similar pattern to EC and the correlation coefficient between OC and EC is 0.89 （n=31）. The average percentage of total carbon （TC, sum of CC, OC, and EC） in Pm2.5 during dust storm （DS） events was 13.6%, which is lower than that during non-dust storm （NDS） periods （22.7%）. CC, OC, and EC accounted for 12.9%, 70.7%, and 16.4% of TC during DS events, respectively. The average ratio of OC/EC was 5.0 in DS events and 3.3 in NDS periods. The OC-EC correlation （R^2=0.76, n=6） was good in DS events, while it was stronger （R^2=0.90, n=25） in NDS periods. The percentage of watersoluble OC （WSOC） in TC accounted for 15.7%, and varied between 13.3% and 22.3% during DS events. The distribution of eight carbon fractions indicated that local emissions such as motor vehicle exhaust were the dominant contributors to carbonaceous particles. During DS events, soil dust dominated the chemical composition, contributing 69% to the Pm2.5 mass, followed by organic matter （12.8%）, sulfate （4%）, EC （2.2%）, and chloride （1.6%）. Consequently, CC was mainly entrained by Asian dust. However, even in the atmosphere near Asian dust source regions, OC and EC in atmospheric dust were controlled by local emission rather titan the transport of Asian dust.

关键词： carbonate carbon organic carbon elemental carbon dust storm

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

Hybrid Power System Options for Off-Grid Rural Electrification in Northern Kenya

引用

Smart Grid and Renewable Energy 2014年第5期5卷 89-106页

作者： June m. Lukuyu judith B. Cardell Picker Engineering Program Smith College Northampton USA

For domestic consumers in the rural areas of northern Kenya, as in other developing countries, the typical source of electrical supply is diesel generators. However, diesel generators are associated with both CO2 emissions, which adversely affect the environment and increase diesel fuel prices, which inflate the prices of consumer goods. The Kenya government has taken steps towards addressing this issue by proposing The Hybrid mini-Grid Project, which involves the installation of 3 mW of wind and solar energy systems in facilities with existing diesel generators. However, this project has not yet been implemented. As a contribution to this effort, this study proposes, simulates and analyzes five different configurations of hybrid energy systems incorporating wind energy, solar energy and battery storage to replace the stand-alone diesel power systems servicing six remote villages in northern Kenya. If implemented, the systems proposed here would reduce Kenya’s dependency on diesel fuel, leading to reductions in its carbon footprint. This analysis confirms the feasibility of these hybrid systems with many configurations being profitable. A multi-Attribute Trade-Off Analysis is employed to determine the best hybrid system configuration option that would reduce diesel fuel consumption and jointly minimize CO2 emissions and net present cost. This analysis determined that a wind-diesel-battery configuration consisting of two 500 kW turbines, 1200 kW diesel capacity and 95,040 Ah battery capacity is the best option to replace a 3200 kW stand-alone diesel system providing electricity to a village with a peak demand of 839 kW. It has the potential to reduce diesel fuel consumption and CO2 emissions by up to 98.8%.

关键词： Hybrid Power System Off-Grid Power System Wind Energy Solar Energy Battery Storage multi-Attribute Trade-Off Analysis

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

Improved estimation of Pm_(2.5) brown carbon contributions to filter light attenuation

引用

Particuology 2021年第3期19卷 1-9页

作者： judith C.Chow L.-W.Antony Chen Xiaoliang Wang mark C.Green John G.Watson Division of Atmospheric Sciences Desert Research InstituteRenoNVUSA State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’anChina Graduate Faculty Department of Atmospheric SciencesUniversity of NevadaReno NevadaUSA Department of Environmental and Occupational Health School of Public HealthUniversity of NevadaLas VegasNVUSA

multiwavelength light attenuation measurements have been acquired as part of thermal/optical carbon analysis in the *** Speciation Network(CSN)and the Interagency monitoring of PROtected Visual Environments(ImPROVE)network beginning in *** are used to estimate Pm_(2.5)brown carbon(BrC)contributions to light absorption at various wavelengths,a useful method for separating biomass burning contributions from other *** of light transmitted through the filter deviates from Beers Law as the mass of light absorbing materials *** study estimates the effects of these deviations with empirical adjustment factors applied to samples for CSN from 2016 to 2017 and for ImPROVE from 2016 to *** for the filter loading effect results in an annual average increase of∼6-7%BrC contribution to light attenuation:from 3.6%to 10.7%for the urban,more heavily loaded CSN samples;and from 23.7%to 29.5%for the non-urban ImPROVE *** alternative method is examined for BrC and black carbon(BC)adjustments by calculating the AbsorptionÅngström Exponent(AAE)for BC(i.e.,AAE_(BC))based on the ratios of 635 nm/780 nm light attenuation rather than assuming AAE_(BC)of *** paired-wavelength calculations result in a median AAE_(BC)of 0.76 for CSN and 0.8 for ImPROVE,with the majority of samples(i.e.,91%of CSN and 70%of ImPROVE)showing AAE_(BC)ming negligible contributions from BrC to AAE at longer wavelengths,the amount of light attenuation at shorter wavelengths(e.g.,405 nm)where BrC is dominant can be *** paired-wavelength method applied to the filter loading adjusted data has a greater effect on urban(fresh)than on non-urban(aged)aerosols,resulting in a factor of two increase in annual averaged BrC light attenuation(from 10.7%to 21.6%)for CSN and by a factor of 1.11(from 29.5%to 32.7%)for ImPROVE *** result demonstrates the importance of particle loading and AAE correction on quantifying BrC light attenuatio

关键词： Organic carbon Brown carbon Elemental carbon Black carbon AbsorptionÅngström Exponent

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

Effects of Land Use on the Riparian Vegetation along the Njoro and Kamweti Rivers, Kenya

引用

Open Journal of Ecology 2021年第11期11卷 807-827页

作者： judith C. Koskey Charles m. m’Erimba George m. Ogendi Department of Environmental Science Egerton University Egerton Kenya Department of Biological Sciences Egerton University Egerton Kenya Dryland Research Training and Ecotourism Centre Chemeron Egerton University Egerton Kenya

Riparian zones are valuable ecosystems. They act as the ecological engineers that improve river health by delivering a range of ecosystem functions. They play a significant role in river health and provide various ecosystem goods and services for human well-being. Currently, riparian areas are under threat due to intensive human activities such as agriculture and urbanization, which alter riparian ecosystem structure and composition. The main objective of this study was to determine the effect of adjacent land use on the structure and diversity of the riparian vegetation in the Njoro and Kamweti Rivers. Along each river, three sampling sites were selected within the major land use categories which were;forest, agricultural and built-up areas. At each site, three 70 m long transects were established perpendicular to the river. The three plots were systematically established, separated by a 5 m distance along each transect. Forest canopy cover was estimated in percentage. Njoro River riparian vegetation recorded a total of 145 plant species from 40 families where trees and shrubs were dominant in the forest area, and herbs dominated the agricultural and built-up areas. In Kamweti River riparian area, a total of 110 species from 45 families were encountered, in which trees dominated the forest area. A similar trend to the Njoro River was observed, in which herbs were dominant in the agricultural and built-up areas. In Njoro River, the Shannon diversity (H’) values ranged between 2.73 and 3.08 whereas Kamweti River riparian area values ranged from 2.59 to 3.40. At the level of P ≤ 0.05, T-Test revealed that there was no significant difference in plant abundance and diversity between the two rivers, with F = 0.53;P = 0.51 and F = 2.71;P = 0.17. Human-centered disturbances along the Njoro and Kamweti River riparian areas have affected the riparian vegetation as shown by the decrease in plant species diversities, and the change in vegetation composition and distribution ac

关键词： Land Use Riparian Vegetation Composition Distribution Diversity

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

Restoring the dampened expression of the core clock molecule BmAL1 protects against compression-induced intervertebral disc degeneration

引用

Bone Research 2022年第2期10卷 297-309页

作者： Dong Wang Pandi Peng michal Dudek Xueyu Hu Xiaolong Xu Qiliang Shang Di Wang Haoruo Jia Han Wang Bo Gao Chao Zheng Jianxin mao Chu Gao Xin He Pengzhen Cheng Huanbo Wang Jianmin Zheng judith A.Hoyland Qing-Jun meng Zhuojing Luo Liu Yang Institute of Orthopedic Surgery Xijing HospitalFourth Military Medical UniversityXi’an 710032People’s Republic of China medical Research Institute Northwestern Polytechnical UniversityXi’an 710068People’s Republic of China School of Biological Sciences Faculty of BiologyMedicine and HealthUniversity of ManchesterManchester M139PLUK Wellcome Centre for Cell matrix Research University of ManchesterManchester M139PLUK Department of medicine Chemistry and Pharmaceutical Analysis School of PharmacyFourth Military Medical UniversityXi’an 710032People’s Republic of China Radiology Department Xijing HospitalFourth Military Medical UniversityXi’an 710032People’s Republic of China

The circadian clock participates in maintaining homeostasis in peripheral tissues,including intervertebral discs(IVDs).Abnormal mechanical loading is a known risk factor for intervertebral disc degeneration(IDD).Based on the rhythmic daily loading pattern of rest and activity,we hypothesized that abnormal mechanical loading could dampen the IVD clock,contributing to ***,we investigated the effects of abnormal loading on the IVD clock and aimed to inhibit compression-induced IDD by targeting the core clock molecule brain and muscle Arnt-like protein-1(BmAL1).In this study,we showed that BmAL1 KO mice exhibit radiographic features similar to those of human IDD and that BmAL1 expression was negatively correlated with IDD severity by systematic analysis based on 149 human IVD *** intrinsic circadian clock in the IVD was dampened by excessive loading,and BmAL1 overexpression by lentivirus attenuated compression-induced *** of the RhoA/ROCK pathway by Y-27632 or melatonin attenuated the compression-induced decrease in BmAL1 ***,the two drugs partially restored BmAL1 expression and alleviated IDD in a diurnal compression *** results first show that excessive loading dampens the circadian clock of nucleus pulposus tissues via the RhoA/ROCK pathway,the inhibition of which potentially protects against compression-induced IDD by preserving BmAL1 *** findings underline the importance of the circadian clock for IVD homeostasis and provide a potentially effective therapeutic strategy for IDD.

关键词： BmAL1 degeneration homeostasis

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

Dilution sampling and analysis of particulate matter in biomass-derived syngas

引用

Frontiers of Environmental Science & Engineering 2011年第3期5卷 320-330页

作者： Xiaoliang WANG Curtis ROBBINS S.Kent HOEKmAN judith C.CHOW John G.WATSON Dennis SCHUETZLE Division of Atmospheric Sciences Desert Research Institute(DRI)RenoNV 89512USA Renewable Energy Institute International(REII)McClellanCA 95652USA

Thermochemical biomass gasification,followedby conversion of the produced syngas to fuels andelectrical power,is a promising energy *** of particulate matter(Pm)and othercontaminants in the syngas is important to minimizedamage and ensure efficient operation of the engines itpowers and the fuels created from it.A dilution samplingsystem is demonstrated to quantify Pm in syngas generatedfrom two gasification plants utilizing different biomassfeedstocks:a Biomax®15 Biopower System that uses rawand torrefied woodchips as feedstocks,and an integratedbiorefinery(IBR)that uses rice hulls and woodchips ***_(2.5)mass concentrations in syngas from theIBR downstream of the purification system were 12.8-13.7μg·m^(-3),which were significantly lower than themaximum level for catalyst protection(500μg·m^(-3))andwere 2-3 orders of magnitude lower than those inBiomax®15 syngas(2247-4835μg·m^(-3)).Ultrafine particlenumber concentration and Pm_(2.5)chemical constituentswere also much lower in the IBR syngas than in theBiomax®*** dilution sampling system enabledreliable measurements over a wide range of concentrations:the use of high sensitivity instruments allowed measurementat very low concentrations(~1μg·m^(-3)),while theflexibility of dilution minimized sampling problems thatare commonly encountered due to high levels of tars in rawsyngas(~1 g·m^(-3)).

关键词： dilution source sampling syngas characterization biomass gasification ultrafine particles

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

Potential emission reductions by converting agricultural residue biomass to synthetic fuels for vehicles and domestic cooking in China

引用

Particuology 2020年第2期18卷 40-47页

作者： Xiaoliang Wang SKent Hoekman Yang Han judith CChow John G.Watson Xiaomeng Wu Ye Wu Dennis Schuetzle Robert Schuetzle Desert Research Institute 2215 Raggio PkwyRenoNV 89512USA School of Environment Tsinghua UniversityBeijing 100084China Greyrock Energy Inc.2020 L StreetSuite 120SacramentoCA 95811USA

Vehicle exhaust and transported biomass burning emissions are important air pollution sources in many urban areas,and domestic cooking with biomass fuels causes indoor air pollution in many rural *** agricultural waste-generated synthetic fuels can reduce emissions both from vehicles and biomass *** estimate the potential benefits of synthetic diesel in Beijing,the emission factor model for the Beijing vehicle fleet was applied to estimate exhaust emissions for the 2015-2030 *** with 100%petroleum diesel,a 20%synthetic diesel blend reduced diesel fleet emissions by 24%for carbon monoxide,30%for total hydrocarbons,5.5%for nitrogen oxides,and 19%for fine particulate matter with an aerodynamic diameter of≤2.5μm(Pm2.5)while using 100%synthetic diesel decreased emissions by 36%for carbon monoxide,48%for total hydrocarbons,10%for nitrogen oxides,and 34%for *** use of biomass for producing synthetic fuels rather than burning in the field also reduces air *** 60g of Pm2.5 agricultural open-field burning emissions are avoided per liter of synthetic fuel *** solid crop residues with synthetic liquid fuels in household cooking would reduce Pm2.5 emissions by more than 90%.

关键词： Pm2.5 Air pollution Vehicle emission Biomass burning Synthetic fuel Agricultural biomass

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

Characterization of organic-rich mineral debris revealed by rapid glacier retreat, Indren Glacier, European Alps

引用

Journal of mountain Science 2021年第6期18卷 1521-1536页

作者： FREPPAZ michele WILLIAmS mark W. GABRIELI Jacopo GORRA Roberta mANIA Ilaria ASCHER-JENULL judith EGLI markus CELI Luisella Department of Agriculture Forest and Food SciencesUniversity of TurinLargo Paolo Braccini 210095 Grugliasco(TO)Italy NatRisk Research Centre on Natural Risks in mountain and Hilly Environments University of TurinLargo Paolo Braccini 210095 Grugliasco(TO)Italy Institute of Arctic and Alpine Research and Department of Geography University of Colorado at BoulderUCB 450BoulderCO 80309USA CNR-ISP(Consiglio Nazionale delle Ricerche Istituto di Scienze Polari)via Torino 15530172 Venezia-MestreItaly Institute of microbiology University of InnsbruckTechnikerstraße 256020 InnsbruckAustria Department of Geography University of ZurichWinterthurerstrasse 1908057 ZurichSwitzerland

In the summer of 2003 and 2004, characterized by a rapid glacier retreat, a stony surface covered by well-structured organic-rich mineral debris was observed very close to the Indren glacier terminus(monte Rosa massif, NW Italy, 3100 m ASL), on an area covered by the glacier tongue till the year before. The origin and type of this organicrich material were investigated, in order to detect their characteristics, potential sources and fate within the foreland system. The deposits were dated using Carbon-14 and analyzed for the chemical characteristics of the organic component, the elemental composition of the mineral fraction and presence of microbial markers. The material, granular and dark in color, had a total organic carbon(TOC) content ranging between 17.4 ± 0.39 and 28.1 ± 0.63 g kg^(-1) dry weight(dw), significantly higher than the surrounding glacial till(~ 1.4 g kg^(-1) dw), although only 0.33% of it was in water soluble form. microbial carbon(C) and nitrogen(N) accounted for 10.6% and 3.13% of TOC and total N, respectively. Dissolved nitrogen(N), mainly present as ammonium, represented 2.40% of the total N. The low aromatic component and large presence of nitrogen(N)-derived compounds suggested that most of the organic carbon(OC) in these organic-rich mineral deposits was derived from microbial cells, although the high average radiocarbon age of about 2900 years may also point to the contribution of aeolian depositions of anthropogenic or natural origin. Elemental composition and the crustal enrichment factor of trace elements in the mineral fraction of the aggregates corroborated the hypothesis that most part of the accumulated material derived from ice meltwater. Some indicators of the colonization of these deposits by microbial communities were also reported, from the abundance of DNA and phylogenetic markers, to the presence of bacterial taxa commonly able to thrive in similar habitats. All these elements suggested that such kind of deposits may have a p

关键词： Glacier foreland Dissolved organic carbon Organic matter q PCR microbial community Trace elements

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

High resolution colonoscopy in a bowel cancer screening program improves polyp detection

引用

World Journal of Gastroenterology 2011年第38期17卷 4308-4313页

作者： matthew R Banks Rehan Haidry m Adil Butt Lisa Whitley judith Stein Louise Langmead Stuart L Bloom Austin O' Bichere Sara mcCartney Kalpesh Basherdas manuel Rodriguez-Justo Laurence B Lovat Department of Gastrointestinal Services University College London Hospitals NHS Foundation Trust Department of Histopathology University College London Hospitals NHS Foundation Trust

AIm:To compare high resolution colonoscopy(Olympus Lucera) with a megapixel high resolution system(Pentax HiLine) as an in-service ***:Polyp detection rates and measures of performance were collected for 269 colonoscopy *** colonoscopists conducted the study over a three month period,as part of the United Kingdom bowel cancer screening ***:There were no differences in procedure duration(χ2 P = 0.98),caecal intubation rates(χ2 P = 0.67),or depth of sedation(χ2 P = 0.64).mild discomfort was more common in the Pentax group(χ2 P = 0.036).Adenoma detection rate was significantly higher in the Pentax group(χ2 test for trend P = 0.01).most of the extra polyps detected were flat or sessile ***:megapixel definition colonoscopes improve adenoma detection without compromising other measures of endoscope *** polyp detection rates may improve future outcomes in bowel cancer screening programs.

关键词：高分辨率检查程序筛查肠癌检测肉大肠百万像素

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

NG2 Cell Response in the CNP-EGFP mouse After Contusive Spinal Cord Injury

引用

神经损伤与功能重建 2009年第1期4卷 33-47页

作者： judith m LYTLE RAmESH CHITTAJALLU JEAN R WRATHALL VITTORIO GALLO Department of Neuroscience Georgetown University Interdisciplinary Program in Neuroscience Georgetown University Center for Neuroscience Research Children's National Medical Center

成年动物中枢神经系统中的NG2细胞具有异质性。脊髓损伤(SCI)后,具有少突胶质前体细胞(OPCs)功能的NG2细胞亚型如何产生反应性变化及对其正常的发育过程有何影响目前还不清楚。本文采用少突胶质细胞系细胞表达EGFP的CNP-EGFP小鼠,研究... 详细信息

成年动物中枢神经系统中的NG2细胞具有异质性。脊髓损伤(SCI)后,具有少突胶质前体细胞(OPCs)功能的NG2细胞亚型如何产生反应性变化及对其正常的发育过程有何影响目前还不清楚。本文采用少突胶质细胞系细胞表达EGFP的CNP-EGFP小鼠,研究正常和SCI后的NG2细胞的特征。在正常小鼠的白质中,对EGFP+NG2+双极细胞和EGFPnegNG2+多极细胞进行鉴别。SCI后,白质损伤边缘区中的EGFP+NG2+细胞3 d增殖达高峰,损伤中心区的EGFPnegNG2+细胞增殖在损伤后7 d达高峰。损伤后EGFP+NG2+细胞的Olig2、Sox10、Sox17等转录因子、基本的膜电生理参数以及钾电流表型均与发育过程增殖的OPCs一致。EGFPnegNG2+细胞不表达少突胶质发生中的转录因子。EGFP+CC1+少突胶质细胞6周时包含在EGFP+NG2+细胞增殖峰时表达BrdU的细胞。EGFPnegCC1+少突胶质细胞未被观察到。神经胶质生长因子2和成纤维细胞生长因子2处理促进少突胶质发生,提高EGFPnegNG2+细胞数量。因此,通过EGFP和转录因子表达,时空增殖类型及对生长因子的反应,两种类型的NG2+细胞对SCI刺激发生反应。SCI后EGFP+NG2+细胞经受细胞和生理变化特征,与在早期出生后的少突胶质发生过程中NG2+细胞中的变化类似。

关键词：少突胶质前体细胞 olig2 CNP基因内源性修复细胞增殖神经胶质生长因子成纤维细胞生长因子

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

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：