磺化石墨烯对小麦幼苗生长及生理生化指标的影响

随着石墨烯生产量和使用量的不断增大,其对生态环境的风险逐渐引起了环境学家的关注。采用水培试验,探究了磺化石墨烯(SGO)对小麦幼苗的生长、抗氧化酶活性及脂质过氧化的影响。结果表明:在培养10 d后,低浓度磺化石墨烯对小麦根系的生长有显著促进作用(P0.05),200 mg·L-1浓度处理与对照处理相比提高了84.3%,随着浓度增加促进作用逐渐减弱,1 000 mg·L-1时与对照相比提高了19.9%。但对小麦地上部的生长没有影响。磺化石墨烯处理的小麦幼苗根系和叶片组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)及丙二醛(MDA)都呈现先下降后上升的趋势。当磺化石墨烯浓度低于200 mg·L-1时,处理组小麦抗氧化酶的活性及MDA含量相对于对照处理大都有所降低,说明低浓度时磺化石墨烯没有对小麦的生长产生氧化胁迫,这与磺化石墨烯可能具有一定的抗氧化能力有关,而高浓度时由于产生氧化胁迫使各项生理生化指标逐渐上升。本实验结果为石墨烯材料对植物的毒理学研究提供了基础数据。     

2013年1月北京市一次空气重污染成因分析

采用数值模式与观测资料相结合的方式,对北京市2013年1月9日至15日一次空气重污染过程的大气环境背景、气象条件和形成原因进行了初步分析.结果表明,重污染过程期间10日至14日PM2.5平均值为323μg·m-3;重污染过程与当地气象条件密切相关,稳定的大气环流形势为污染的持续提供了大气环流背景,风速较小、湿度较大、边界层较低、持续逆温是造成重污染的主要原因;重污染过程中区域输送对北京PM2.5贡献率在53%~69%之间且存在明显的二次转化,区域输送起着更为重要的作用;气象条件对持续性重污染的形成和破坏起到了关键性的作用,因此需要加强对重污染预警预报研究,以有效预防和控制空气重污染.     

Quality assured measurements of animal building emissions: gas concentrations

Comprehensive field studies were initiated in 2002 to measure emissions of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), methane (CH4), nonmethane hydrocarbons (NMHC), particulate matter <10 microm in diameter, and total suspended particulate from swine and poultry production buildings in the United States. This paper focuses on the quasicontinuous gas concentration measurement at multiple locations among paired barns in seven states. Documented principles, used in air pollution monitoring at industrial sources, were applied in developing quality assurance (QA) project plans for these studies. Air was sampled from multiple locations with each gas analyzed with one high quality commercial gas analyzer that was located in an environmentally controlled on-farm instrument shelter. A nominal 4 L/min gas sampling system was designed and constructed with Teflon wetted surfaces, bypass pumping, and sample line flow and pressure sensors. Three-way solenoids were used to automatically switch between multiple gas sampling lines with > or =10 min sampling intervals. Inside and outside gas sampling probes were between 10 and 115 m away from the analyzers. Analyzers used chemiluminescence, fluorescence, photoacoustic infrared, and photoionization detectors for NH3, H2S, CO2, CH4, and NMHC, respectively. Data were collected using personal computer-based data acquisition hardware and software. This paper discusses the methodology of gas concentration measurements and the unique challenges that livestock barns pose for achieving desired accuracy and precision, data representativeness, comparability and completeness, and instrument calibration and maintenance.     

System dynamic analysis of construction waste recycling industry chain in China

Environmental Science and Pollution Research - With the acceleration of China’s urbanization process, construction activities have led to a substantial increase in construction waste....     

The impact of coal and non-coal consumption on China's energy performance improvement

China is the world's largest energy consumer, and coal accounts for a higher proportion of the country's total energy consumption, yet during its 12th five-year plan (2011–2015), the coal share among total energy consumption significantly decreased. Previous studies exploring energy performance typically used energy consumption as an input, but this lacks the analytical capacity for the structure of energy consumption. Thus, this study splits energy input into two different inputs, coal consumption and non-coal energy consumption, and based on their differences with other variables, uses the hybrid dynamic data envelopment analysis model to assess the energy performance of China's provincial industrial sector during the period 2011 to 2015. We then compare coal consumption's and non-coal consumption's rooms for improvement and conclude that provinces in eastern and central China should reduce the amount of coal consumption, thereby improving energy performance. Conversely, provinces in the western region should target a balance between energy utilization efficiency and coal consumption.     

多环芳烃的零阶价分子连接性指数与正-辛醇/水分配系数

本文建立了准确预测多环芳烃(PAHs)及其烷基衍生物的正-辛醇/水分配系数(Kow)模型。模型表明PAHs的分配性质可用零阶价分子连接性指数(~°x~v)描述,~°x~v数值与PAHs的logKow成正比。应用本模型可以预测大范围PAHs的logKow值。     

Climate change: potential impact on plant diseases

Global climate has changed since pre-industrial times. Atmospheric CO(2), a major greenhouse gas, has increased by nearly 30% and temperature has risen by 0.3 to 0.6 degrees C. The intergovernmental panel on climate change predicts that with the current emission scenario, global mean temperature would rise between 0.9 and 3.5 degrees C by the year 2100. There are, however, many uncertainties that influence these predictions. Despite the significance of weather on plant diseases, comprehensive analysis of how climate change will influence plant diseases that impact primary production in agricultural systems is presently unavailable. Evaluation of the limited literature in this area suggests that the most likely impact of climate change will be felt in three areas: in losses from plant diseases, in the efficacy of disease management strategies and in the geographical distribution of plant diseases. Climate change could have positive, negative or no impact on individual plant diseases. More research is needed to obtain base-line information on different disease systems. Most plant disease models use different climatic variables and operate at a different spatial and temporal scale than do the global climate models. Improvements in methodology are necessary to realistically assess disease impacts at a global scale.     

Effect of photosensitizer diethylamine on the photodegradation of polychlorinated biphenyls

The objective of this study was to investigate the effect of diethylamine and xenon simulated sunlight on the photodegradation of two forms of PCBs including PCBs in transformer oil and PCB congener 138. The result of GC chromatograms illustrated the shifting pattern of higher chlorinated biphenyls in transformer oil degraded to lower chlorinated biphenyls with the extension of exposure time. The effect of diethylamine and xenon simulated sunlight was significant on the photodegradation of both PCBs in transformer oil and congener 138. The initial degradation rates of congener 138 (1.14 x 10(-9) to 4.47 x 10(-9) mol l(-1) h(-1)) were in direct proportion to the initial concentrations of congener 138 which confirmed the pseudo-first-order reaction of PCB photodegradation. The apparent quantum yields (phi) of congener 138 using diethylamine in xenon photoreactor were ranged between 2.08 x 10(-2) and 9.8 x 10(-4). PCB congeners 123, 97, 70, 67, 33, 29, 17, 12, and 9 were detected as the descendants of the photodegradation of congener 138 through dechlorination. The major pathway of congener 138 photodegradation in this study was via para-dechlorination.     

Effect of experimental factors on nitrobenzaldehyde photoisomerization

The objective of this study was to compare the effect of various experimental factors on the photoisomerization of nitrobenzaldehyde. The experimental factors included light source, light energy, exposure time, light path distance and the concentration of nitrobenzaldehyde. The results showed that the photoisomerization of nitrobenzaldehyde increased with increasing light exposure. Different light sources and light path distances demonstrated significant impact on the reaction rate constants and half-lives of nitrobenzaldehyde. Although the light energy of UV photoreactor was 47% lower than that of xenon photoreactor, quantum yield and UV/VIS absorption pattern confirmed the finding that the effect of ultraviolet photoreactor on nitrobenzaldehyde was similar to that of xenon photoreactor with the light path of 17 cm. It was caused by the shorter wavelength of UV photoreactor mainly on 254 nn. The product of nitrobenzaldehyde photoisomerization, nitrosobenzoic acid, was detected from samples after 5 or 10 min exposure of three light sources. The concentrations of nitrosobenzoic acid increased with the increasing of exposure time up to 20 or 60 min.     

中国江河氧化亚氮的排放及其影响因素

氧化亚氮（N₂O）是一种在大气中存留时间很长的强效温室气体,并被认为是21世纪破坏臭氧层的重要物质之一,气候预测需要对自然与人为排放的包括N₂O在内的温室气体进行全面准确地估算.内陆水体是N₂O的重要排放源,由于人为氮输入的增加,江河N₂O的排放量可能逐年升高.本研究总结了江河N₂O排放速率的研究方法,重点汇总了中国各气候带十大流域江河N₂O的溶存浓度和水气界面交换通量,并与世界其他河流进行比较.结果表明我国江河溶存N₂O浓度为0.3~1591 nmol·L^-1,N₂O释放通量为-12.2~2262.1 μmol·m^-2·d^-1,总体与世界其他江河的范围值具有可比性.在此基础上,进一步分析了江河N₂O的产生和释放机理,探讨了水中溶解性无机氮、溶解氧、有机碳以及水文、地形地貌与气象条件等对江河N₂O产生和释放的影响,并讨论了变化环境下江河N₂O的排放特征.