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961.
Iwasaka Y Shi GY Kim YS Matsuki A Trochkine D Zhang D Yamada M Nagatani T Nagatani M Shen Z Shibata T Nakata H 《Environmental monitoring and assessment》2004,92(1-3):5-24
Measurements of aerosols were made in 2001 and 2002 at Dunhuang (40 degrees 00'N, 94 degrees 30'E), China to understand the nature of atmospheric particles over the desert areas in the Asian continent. Balloon-borne measurements with an optical particle counter suggested that particle size and concentration had noticeable peaks in super micron size range not only in the boundary mixing layer but also in the free troposphere. Super-micron particle concentration largely decreased in the mid tropopause (from 5 to 10 km; above sea level, a.s.l.). Lidar measurements made during August 2002 at Dunhuang suggested the possibility that mixing of dust particles occurred from near the ground to about 6 km even under calm weather conditions, and a large depolarization ratio of particulate matter was found in the aerosol layer. The top of the aerosol layer was found at heights of nearly 6 km (a.s.l.). It is strongly suggested that nonspherical dust particles (Kosa particles) frequently diffused in the free atmosphere over the Taklamakan desert through small-scale turbulences and are possible sources of dust particles of weak Kosa events that have been identified in the free troposphere not only in spring but also in summer over Japanese archipelago. Electron microscopic experiments of the particles collected in the free troposphere confirmed that coarse and nonspherical particles observed by the mineral particle were major components of coarse mode (diameter larger than 1 microm) below about 5 km over Dunhuang, China. 相似文献
962.
Changes Of Hydrological Environment And Their Influences On Coastal Wetlands InThe Southern Laizhou Bay, China 总被引:2,自引:0,他引:2
The structure and function of the coastal wetland ecosystem in the southern Laizhou Bay have been changed greatly and influenced by regional hydrological changes. The coastal wetlands have degraded significantly during the latest 30 years due to successive drought, decreasing of runoff, pollution, underground saline water intrusion, and aggravating marine disasters such as storm tides and sea level rising. Most archaic lakes have vanished, while artificial wetlands have been extending since natural coastal wetlands replaced by salt areas and ponds of shrimps and crabs. The pollution of sediments in inter-tidal wetlands and the pollution of water quality in sub-tidal wetlands are getting worse and therefore “red tides” happen more often than before. The biodiversity in the study area has been decreased. Further studies are still needed to protect the degraded coastal wetlands in the area. 相似文献
963.
Comparative on Causes and Accumulation of Selenium in the Tree-rings Ambient High-selenium Coal Combustion Area from Yutangba, Hubei, China 总被引:1,自引:0,他引:1
Liu G Zhang Y Qi C Zheng L Chen Y Peng Z 《Environmental monitoring and assessment》2007,133(1-3):99-103
Toxic trace elements emitted during coal combustion are the main sources of air pollution. They are released into the atmosphere
mainly in the forms of fine ash, smoke and flue, and thus adversely affect plant, animal and human health. Selenium is one
of toxic and the most volatile in coal. Large amount of atmospheric emission of selenium, as well as selenium present and
scrubber stockpiles in ash may create serious environmental problems. In the paper, on the basis of investigating the abundance
and distribution of selenium in plant-rings during recent 20 years, the bioaccumulation of selenium is explained that selenium
in plant, which were collected from the village of selenium-rich coal combustion, is much higher than that in plants collected
away from the village of selenium-rich coal combustion. The main origins of selenium are selenium-rich coal combustion and
high-selenium rock weathered. The selenium recycle by food chain and selenium will accumulate and redistribute in environments. 相似文献
964.
The determination of trace amount nitrobenzene in wastewater on a hanging mercury drop electrode was studied. The determination
conditions of pH, supporting electrolyte, accumulation potential, accumulation time, and voltammetric response were optimized.
The sharp peak of the nitrobenzene was appeared at 0.05 V. The peak electric current was proportional to the concentration
of nitrobenzene in the range of 1.47 × 10−5 ∼ 1.0 × 10−3 mol/l with relative standard deviations of 3.99 ∼ 8.94%. The detection limit of the nitrobenzene in water was 5 × 10−6 mol/l. The proposed method offered low limit of determination, easy operation, the use of simple instrumentation, high sensitivity
and good reproducibility. It was applied to the determination of nitrobenzene in wastewater with an average recovery of 94.0%
∼ 105%. The proposed method provided fast, sensitive and sometimes real time detection of nitrobenzene. 相似文献
965.
End-users’ knowledge,attitude, and behavior towards safe use of pesticides: a case study in the Guanting Reservoir area,China 总被引:1,自引:0,他引:1
Pesticides are widely used in China for crop protection. However, the use of some highly toxic and accumulative pesticides
has led to serious pollution to the environment. The knowledge that end-users of pesticides have about hazards is important
for the prevention of acute poisoning. Moreover, farmers, especially those who purchase and use pesticides, often make important
and long-standing impacts on the local ecosystem and environment. In this study, a specially designed questionnaire was used
to collect information on their knowledge, attitude, and behavior related to pesticides in the Guanting Reservoir area, north
of China. Most pesticide end-users reported that they took incomplete preventive measures for lack of extensive pesticide
knowledge and information. Pesticide information, instruction, and training among farmers should be promoted, and governmental
intervention is needed to ensure proper management regarding public health risks and environmental hazards. 相似文献
966.
Xinhua Fu Fredric V. Vencl Ohba Nobuyoshi V. Benno Meyer-Rochow Chaoliang Lei Zhongning Zhang 《Chemoecology》2007,17(2):117-124
Summary. When attacked or otherwise disturbed, larvae of the aquatic firefly Luciola leii display fork-shaped glands laterally from the meso- and metathorax as well as each abdominal segment. Glandular eversion
is accompanied by a strong pine oil-like odour, thanatosis and glowing from paired larval light organs. Observations by SEM
and TEM revealed that there are numerous, almost spherical protuberances, measuring 9 μm in diameter on the surface of each
gland. Each protuberance is connected to a well developed secretory cell via a 0.1 μm thick and 0.2 μm long stalk and bears
three to six 7 μm long spines on its apex. The convoluted glandular walls measure 0.2 μm. The cytoplasm of the secretory cells
is characterized by the presence of numerous mitochondria and an extensive system of cisternae and tubular endoplasmic reticulum.
Preliminary GC-MS analysis of the glandular secretion revealed two volatile terpenoids: terpinolene and γ-terpinene. Choice
and no-choice bioassays involving fish and ants as well as other predators demonstrate that the secretions serve as an effective
deterrent against a range of ecologically relevant enemies. The larval postural adjustments, light emission, everted glands,
and glandular release of distasteful or repellent compounds, appear to function as a multi-modal, aposematic larval defence.
The tandem evolution of glandular secretions and conspicuousness in larval fireflies could partially explain their successful
radiation into both aquatic and terrestrial habitats. 相似文献
967.
Zhongwei Guo Yiming Li Xiangming Xiao Lin Zhang Yaling Gan 《Ecological applications》2007,17(6):1557-1562
Globally, particularly in developing countries, hydroelectricity production and economic growth occur together with ecosystem/biodiversity conservation in watersheds. There is a relationship between hydroelectricity production and ecosystem/biodiversity conservation in watersheds, centering on the supply and demand for ecosystem services of river water flow regulation and sediment retention. Here we show that, in the upper reach of the Yangtze River, hydroelectricity production of Three Gorges Hydroelectric Power Plant can form a beneficial relationship with forest conservation through the paid use (compensating residents for their cooperation in the conservation) of ecosystem services launched by the National Natural Forest Protection Project. This interaction can provide additional incentives to encourage local communities' long-term cooperation in conserving and protecting the restored forest ecosystems. Hydroelectricity plants also obtain benefits from this interaction. The industrialization of ecosystem services supply provides an operational framework for this beneficial interaction. Sustainable forest ecosystem conservation will require developing new institutions and policies and must involve local communities in the conservation and protection of their local forests. 相似文献
968.
Xinjie Wang Yang Li Jian Zhao Hong Yao Siqi Chu Zimu Song Zongxian He Wen Zhang 《Frontiers of Environmental Science & Engineering》2020,14(4):56
969.
Youfen Xu Zong Li Ruyin Liu Hongxia Liang Zhisheng Yu Hongxun Zhang 《Frontiers of Environmental Science & Engineering》2020,14(4):67
970.
Yingdan Zhang Na Liu Wei Wang Jianteng Sun Lizhong Zhu 《Frontiers of Environmental Science & Engineering》2020,14(6):103