检索结果-南通市图书馆

Effect of copper on phospholipid fatty acid composition of microbial communities in two red soils

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2006年第3期18卷 503-509页

作者： YAO Huai-ying LIU Yue-yan xue dong HUANG Chang-yong Institute of Soil and Water Resources and Environmental Science Zhejiang University Hangzhou 310029 China

The phospholipid fatty acid （PLFA） composition was analyzed in two red soils experimentally contaminated with copper at different concentrations. The total amounts ofphospholipid fatty acids （PLFAs） in both red soils were significantly correlated with soil microbial biomass C and N, which decreased consistently with increasing levels of copper. The relative quantities of the PLFAs 17：0 （10 Me）, i16：0, il 5：0 and 16：1w5c, decreased with increasing heavy metal concentration, while those of cyl7：0, which is an indicator of gram-negative bacteria, increased. The Shannon index calculated from the PLFA data indicated that Cu addition in the red soils decreased the population diversity of soil microbial communities. Multivariate analysis of PLFA data demonstrated that high levels of Cu application had a significant impact on microbial community structure and there is a threshold metal concentration for PLFA composition. Comparatively higher toxic effect on microbial biomass and community structure were found in the red sandy soil than those in the red clayey soil. The differential effect of Cu addition on microbial communities in the two soils may be due to differences in soil texture and cation exchange capacity.

关键词： copper phospholipid fatty acid microbial biomass red soil

增温强度对晋北赖草草地CH_(4)通量的影响

在线全文

学校读者我要写书评

暂无评论

草地学报 2024年第1期32卷 113-120页

作者：彭洁卢英帅齐志远燕学东武帅楷郝杰陈晓鹏山西农业大学草业学院山西太谷030801 草地生态保护与乡土草种质创新山西省重点实验室山西太谷030801 山西右玉黄土高原草地生态系统国家定位观测研究站山西右玉037200

温度变化通过影响土壤甲烷代谢微生物及相关酶的活性进而影响草地生态系统CH_(4)通量。为明确晋北赖草(Leymus secalinus)草地生态系统CH_(4)通量随气温升高的变化趋势及机理,采用开顶箱法(Open top chambers, OTCs)设置5个梯度的增温处... 详细信息

温度变化通过影响土壤甲烷代谢微生物及相关酶的活性进而影响草地生态系统CH_(4)通量。为明确晋北赖草(Leymus secalinus)草地生态系统CH_(4)通量随气温升高的变化趋势及机理,采用开顶箱法(Open top chambers, OTCs)设置5个梯度的增温处理,对增温第4年各处理生长季CH4通量及其影响因素进行测定。结果表明:增温显著提高了空气温度,但随着空气温度的增加,土壤温度和土壤体积含水量无显著变化;生长季晋北赖草草地生态系统是弱的大气CH_(4)汇,其CH_(4)平均吸收速率为(6.42±5.63)μg·m^(-2)·h^(-1);增温显著影响CH_(4)通量和pmoA功能基因丰度,与对照相比,只有W1处理促进CH4吸收通量;冗余分析表明土壤体积含水量是同时影响pmoA基因丰度和CH_(4)吸收速率的关键因子。本研究可为预测未来气候变暖情境下草地生态系统CH4通量变化提供理论依据。

关键词： OTC 温室气体功能基因甲烷吸收

Landfill leachate production, quality and recirculation treatment in northeast China

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2006年第4期18卷 625-628页

作者： ZHAO Qing-liang LIU xue-yan QI Xu-dong LIU Zhi-gang School of Municipal and Environment Engineering Harbin Institute of Technology Harbin 150090 China

Landfill leachate recirculation treatment process is a promising and economic way in northeast China due to the distinct season variation. In order to study the impact of recirculation on leachate production and its quality, two simulated sanitary landfill reactors, one with leachate recirculation and the other without, were placed outdoor in Harbin. The two-year experimental results indicated that leachate production was reduced by 86% with leachate recirculation and less or no facility for leachate treatment required. Recirculation could improve the leachate quality dramatically with lower COD, SS, NF4-N and higher pH level. Recirculation also could enhance waste degradation and stabilization and improve the efficiency of landfill. This study confirmed that leachate recirculation was a very feasible way for on-site landfill leachate treatment in cold areas.

关键词： cold area sanitary landfill leachate recirculation solid waste

All-fiberized very-large-mode-area Yb-doped fiber based high-peak-power narrow-linewidth nanosecond amplifier with tunable pulse width and repetition rate

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第11期29卷 343-349页

作者： Min yang Ping-xue Li dong-Sheng Wang Ke-Xin Yu xue-yan dong Ting-Ting Wang Chuan-Fei Yao Wei-Xin yang Institute of Laser Engineering Beijing University of TechnologyBeijing 100124China

We demonstrate an all-fiberized narrow-linewidth nanosecond amplifier with high peak power,tunable pulse width,and repetition rate.A fiber-coupled narrow-linewidth laser diode operating at 1064.1 nm is employed as the seed source,which is gain-switched to generate nanosecond pulses with tunable pulse widths of 1-200 ns and tunable repetition rates of10 Hz-100 *** utilizing a very-large-mode-area Yb-doped fiber with a core diameter of 50 μm in the power amplifier,thresholds of the stimulated Brillouin scattering at different pulse widths and repetition rates are *** maximum average power reaches 30.8 W at the pulse width of 4 ns and a repetition rate of 100 kHz,corresponding to an optical-tooptical conversion efficiency of ~55.2%.Pulse energy and peak power are calculated to be 0.2 mJ and 50 kW,respectively,which are limited by stimulated Brillouin *** 3-dB spectral linewidth remains around 0.05 nm during the power scaling *** stimulated Brillouin scattering limited output powers at different pulse widths and repetition rates are *** power of 47.5 kW(0.19 mJ) is obtained for the 4 ns pulses at a repetition rate of 50 kHz,which is nearly the same as that of 4 ns pulses at 100 *** the pulse width of the seed source is increased to 8 ns,peak powers/pulse energies are decreased to 19.6 kW/0.11 mJ and 13.3 kW/0.08 mJ at repetition rates of 50 kHz and 100 kHz,respectively.

关键词： nanosecond all-fiber amplifier very-large mode area tunable pulse width and repetition rate

The 266-nm ultraviolet-beam generation of all-fiberized super-large-mode-area narrow-linewidth nanosecond amplifier with tunable pulse width and repetition rate

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第3期31卷 292-298页

作者： Shun Li Ping-xue Li Min yang Ke-Xin Yu Yun-Chen Zhu xue-yan dong Chuan-Fei Yao Institute of Ultrashort Pulsed Laser and Application Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fiberized nanosecond amplifier architecture, which consists of Yb-doped fiber preamplifiers and a super-large-mode-area Yb-doped fiber power amplifier. The fiber amplifier with a core of 50 μm is used to raise the threshold of the stimulated Brillouin scattering(SBS) effect and to obtain high output power and single pulse energy. Using lithium triborate(LBO) crystal and betabarium borate(BBO) crystal for realizing the second-harmonic generation(SHG) and fourth-harmonic generation(FHG),we achieve 17 μJ(1.73 W) and 0.66 μJ(66 mW), respectively, at wavelengths of 532 nm and 266 nm and a repetition rate of 100 kHz with pulse width of 4 ns. This source has great potential applications in fluorescence research and solar-blind ultraviolet optical communication.

关键词： nanosecond all-fiber amplifier narrow-linewidth ultraviolet beam generation tunable pulse width and repetition rate

Characteristics and Driven Factors of Nitrous Oxide and Carbon Dioxide Emissions in Soil Irrigated with Treated Wastewater

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2012年第8期11卷 1354-1364页

作者： xue yan-dong yanG Pei-ling LUO Yuan-pei LI Yun-kai REN Shu-mei SU yan-ping NIU Yong-tao College of Water Resources and Civil Engineering China Agricultural University Beijing 100083 P.R.China Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Beijing 100081 P.R. China

The reuse of treated wastewater in agricultural systems could partially help alleviate water resource shortages in developing countries. Treated wastewater differs from fresh water in that it has higher concentrations of salts, Escherichia coli and presence of dissolved organic matter, and inorganic N after secondary treatment, among others. Its application could thus cause environmental consequences such as soil salinization, ammonia volatilization, and greenhouse gas emissions. In an incubation experiment, we evaluated the characteristics and effects of water-filled pore space （WFPS） and N input on the emissions of nitrous oxide （N2O） and carbon dioxide （CO2） from silt loam soil receiving treated wastewater. Irrigation with treated wastewater （vs. distilled water） significantly increased cumulative N2O emission in soil （117.97 μg N kg-1）. Cumulative N2O emissions showed an exponentially increase with the increasing WFPS in unamended soil, but the maximum occurred in the added urea soil incubated at 60% WFPS. N2O emissions caused by irrigation with treated wastewater combined with urea-N fertilization did not simply add linearly, but significant interaction （P〈0.05） caused lower emissions than the production of N2O from the cumulative effects of treated wastewater and fertilizer N. Moreover, a significant impact on cumulative CO2 emission was measured in soil irrigated with treated wastewater. When treated wastewater was applied, there was significant interaction between WFPS and N input on N2O emission. Hence, our results indicated that irrigation with treated wastewater should cause great concern for increasing global warming potential due to enhanced emission of N2O and CO2.

关键词： treated wastewater nitrous oxide carbon dioxide water-filled pore space urea

在线全文

学校读者我要写书评

暂无评论

我国肥料标准发展现状、问题与对策

中国土壤与肥料 2024年第5期 212-221页

作者：赵英杰孟远夺樊子风李凡刘少君吴优薛彦东曲明山田有国全国农业技术推广服务中心北京100125 北京市标准化研究院北京100013 华中农业大学经济与管理学院湖北武汉430070 农业农村部种植业管理司北京100125 北京农业技术推广站北京100029

为摸清我国肥料标准现状,加快肥料标准体系建设,收集了我国现行有效的肥料相关国家、行业、地方和团体4个层次的标准,并分别对每个层次所包含标准的技术归口单位、内容和实施时间等进行对比分析,梳理当前我国肥料标准体系存在的问题与不... 详细信息

为摸清我国肥料标准现状,加快肥料标准体系建设,收集了我国现行有效的肥料相关国家、行业、地方和团体4个层次的标准,并分别对每个层次所包含标准的技术归口单位、内容和实施时间等进行对比分析,梳理当前我国肥料标准体系存在的问题与不足,提出进一步完善标准体系的重点方向。结果表明,我国肥料标准涵盖基础通用、产品、检测、施用、生产流通、安全评价等全产业链相关标准类型,基本满足国内行业生产、流通和使用的需要。肥料检测方法和产品标准是国家标准、行业标准的主体,分别占国家标准的54.1%和24.1%,占行业标准的35.1%和34.8%;肥料施用技术类标准在地方标准和团体标准中最多,分别占81.2%和57.1%,我国基本建立了相对完善的肥料标准体系。目前存在的主要问题是产品类标准内容存在一定交叉重复,检测技术标准标龄过长,施用技术标准缺乏统一命名,安全评价类标准相对短缺,标准实施效果评价体系不够完善。未来需要从加强归口单位交流联系、加强标准复审、加快短缺标准立项与研制、加强标准实施效果评价和加强团体标准、企业标准管理等方面努力。

关键词：肥料标准标准体系农业投入品

维普期刊数据库博看期刊

A New Tin Graphite Intercalation Compound for Lithium Ion Batteries

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第5期22卷 639-642页

作者： XIE Hai-ming yan xue-dong YU Hai-ying ZHANG Ling-yun yanG Gui-ling XU yang WANG Rong-shun Department of Chemistry Northeast Normal University Changchun 130024 P. R. China Department of Chemistry Inner Mongolia University for NationalitiesTongliao 028043 P. R. China

A new composite material was fabricated by intercalating tin nanoparticles into graphite. The tin graphite intercalation compound（Sn-GIC） was prepared by the interactions of tin tetrachloride with KC8 （K-GIC） in tetrahydrofuran （THF）. As the anode of lithium ion batteries, Sn-GIC presents a steady reversible capacity（363 mA·h/g） and a good cycling performance in comparison with Sn and SnO2, it suggests that the association of tin with graphite not only improves the reversible capacities, but also prevents the volume changes resulted from lithium insertion and extraction with tin during a charge-discharge process.

关键词： Lithium ion battery Anode material Sn-GIC

Tendencies of alloyed engineering in BiOX-based photocatalysts:a state-of-the-art review

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第4期43卷 1488-1512页

作者： yan-dong Sun Chao Zeng xue Zhang Zi-Qi Zhang Bo yang Sheng-Qi Guo Tianjin Key Laboratory of Clean Energy and Pollutant Control School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China State-Province Joint Engineering Laboratory of Zeolite Membrane Materials Institute of Advanced MaterialsCollege of Chemistry and Chemical EngineeringJiangxi Normal UniversityNanchang330022China Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation School of Physics and Electronic InformationAnhui Province Industrial Generic Technology Research Center for Alumics MaterialsHuaibei Normal UniversityHuaibei235000China

Energy-saving and environmentally friendly photocatalysis has emerged as a popular research area in response to issues with energy scarcity and environmental *** to the unique layer-like structure,BiOX(Cl,Br,I)is frequently used in ***,inherent flaws in BiOX,such as an inappropriate band gap and low carrier separation efficiency,restrict its capacity for *** to the tunable grouping layer,alloying engineering is employed to optimize the intrinsic properties of BiOX and alloyed BiOX becomes a promising photocatalytic *** review describes the structure of BiOX,where tunable halogen layers provide favorable conditions for the implementation of alloying engineering to improve intrinsic *** article compares the effects and mechanisms of alloying engineering on the optimization of the energy band structure and carrier behavior of BiOX,and lists various modification methods used to improve the optimization of the intrinsic properties by alloying engineering,including defect engineering,morphology control as well as the synergy between alloying and other modification methods(bismuth-rich strategies,cation doping,construction of heterojunctions and plasma resonance effects).Subsequently,applications of alloyed BiOX in energy and environmental fields are summarized,including contaminant degradation,antibacterial,CO_(2)reduction,nitrogen fixation and organic ***,we summarize the current challenges and future directions of alloyed *** is expected that this work will provide guidance and assistance for an in-depth study and understanding of the mechanisms of alloying engineering to optimize intrinsic properties and design alloyed BiOX with higher photocatalytic activity.

关键词： Bismuth oxyhalide Photocatalytic Alloyed engineering Microstructural regulation Application