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沉积物中细菌叶绿素的环境指示意义 被引量:3
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作者 王曼 季峻峰 +1 位作者 陈骏 张传伦 《高校地质学报》 CAS CSCD 北大核心 2007年第1期23-29,共7页
沉积物中的光合细菌与细菌叶绿素(BChl)包含着丰富的古湖泊和古海洋信息。对光合细菌的生存环境,BChl的分布、保存、演化规律等方面进行了阐述,并探讨了湖泊和海洋沉积物中BChl的环境指示意义。BChl作为厌氧光合细菌的主要色素,不但可... 沉积物中的光合细菌与细菌叶绿素(BChl)包含着丰富的古湖泊和古海洋信息。对光合细菌的生存环境,BChl的分布、保存、演化规律等方面进行了阐述,并探讨了湖泊和海洋沉积物中BChl的环境指示意义。BChl作为厌氧光合细菌的主要色素,不但可以指示水体中厌氧光合细菌的演变,而且能够反映化变层深度变化和水体环境特征,揭示季节性和年际尺度的气候变化。同时,根据沉积物中BChl含量可以估算古气候环境下湖泊和海洋的厌氧初级生产力。 展开更多
关键词 沉积物 化变层 光合细菌 BChl
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Optimizing data for electrical resistivity tomography in hardened sites through the ratio method
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作者 Jiang Fuyu Gao Likun +2 位作者 Chen Haijun Ni Jiong Li Fuqiang 《Journal of Southeast University(English Edition)》 EI CAS 2024年第4期372-385,共14页
To reduce the shielding effect of hardened layers on electrical resistivity tomography,a ratio method based on the distortion correction principle and the isolation coefficient is proposed.The effects of the resistivi... To reduce the shielding effect of hardened layers on electrical resistivity tomography,a ratio method based on the distortion correction principle and the isolation coefficient is proposed.The effects of the resistivity and thickness of hardened concrete layers on the detection of target objects are explored.Both numerical simulations and indoor tank tests indicate that when the ratio method is employed to correct the original collected data,the maximum allowable error for the isolation coefficient should not exceed 1%.Notably,when the ratio of hardened layer thickness to electrode spacing does not exceed 1,correction through this method significantly enhances the recognition capability of target objects.However,when the hardened layer thickness is greater than the electrode spacing by a factor of 2 or more,the ratio method cannot achieve satisfactory results.The case study of flood control engineering detection in the Zhangxi section of the Huangpen River in Dongzhi County demonstrates that the detection effect after correction by the ratio method is comparable to that for the adjacent unhardened pavement,and the influence of the hardened layer is obviously weakened,resulting in more reliable results. 展开更多
关键词 ratio method resistivity tomography hardened site distortion principle data optimization
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细菌色素在水体环境中的指示作用与意义
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作者 阚家薇 段丽琴 +2 位作者 宋金明 袁华茂 李学刚 《中国环境科学》 EI CAS CSCD 北大核心 2023年第9期4849-4858,共10页
细菌色素(Bchl)作为厌氧光合细菌(APB)的主要色素,其在沉积物中的信息是研究古环境变化的重要生物标志物.系统总结了细菌色素的来源、APB的分布、色素分析测定方法及其在指示古海洋、古湖泊以及现代水生环境的水文条件、极地冰盖变化和... 细菌色素(Bchl)作为厌氧光合细菌(APB)的主要色素,其在沉积物中的信息是研究古环境变化的重要生物标志物.系统总结了细菌色素的来源、APB的分布、色素分析测定方法及其在指示古海洋、古湖泊以及现代水生环境的水文条件、极地冰盖变化和水体缺氧事件发生中的应用.细菌色素主要来源于水体化变层处的绿硫细菌(GSB)和紫硫细菌(PSB)等厌氧光合细菌;PSB的碳同位素分馏较GSB的高.因APB独特的生存环境,产生的色素能够指示湖泊的化变层深度变化及半混合历史.目前针对细菌色素的分析方法主要有光谱法、色谱法及色谱-质谱联用法,其中色谱-质谱联用法在色素定性和定量上有绝对优势.细菌色素在水体和沉积物中的保存易受到物理、化学、生物等因素的干扰,其稳定性还存在不确定性,且其分析方法还在摸索中,需进一步深入探究和优化测定方法和降解保存机制,以便将其广泛运用到古环境、古气候研究中. 展开更多
关键词 细菌叶绿素 厌氧光合细菌 化变层 水体缺氧 古环境
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Application of Composite Ultrafine Particles in ER Fluids
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作者 张少华 夏国栋 魏宸官 《Journal of Beijing Institute of Technology》 EI CAS 1998年第4期395-399,共5页
Aim To obtain a kind of electrorheological (ER) flind with high comprehensive properties in order to satisfy the needs of engineering application. Methods A new type of dispersed phase── composite ultrafine particle... Aim To obtain a kind of electrorheological (ER) flind with high comprehensive properties in order to satisfy the needs of engineering application. Methods A new type of dispersed phase── composite ultrafine particles (UFP) was obtained by the method of microemulsion, which was used to mix with silicon oil. aam electroinduced stress and apparent viscosity of the ER fluids with three different volume fractions were tested under the conditions of different temperatures, electric fields and shear rates. Results A series of systematic tests show that the new type of ER fluids with volume fraction of 30% possesses obvious ER effect. Conclusion The double layers polarization plays an important role in ER effect. 展开更多
关键词 electrorheology ultrafine particles double layers polarization
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Multi-Defect Generation Behavior in Ultra Thin Oxide Under DT Stresses
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作者 霍宗亮 毛凌锋 +1 位作者 谭长华 许铭真 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第2期127-132,共6页
The saturation behavior of stress current is studied.The three types of precursor sites for trap generation are also introduced by fitting method based on first order rate equation.A further investigation by statistic... The saturation behavior of stress current is studied.The three types of precursor sites for trap generation are also introduced by fitting method based on first order rate equation.A further investigation by statistics experiments shows that there are definite relationships among time constant of trap generation,the time to breakdown,and stress voltage.It also means that the time constant of trap generation can be used to predict oxide lifetime.This method is faster for TDDB study compared with usual breakdown experiments. 展开更多
关键词 DEFECT MOS structure time dependence dielectric breakdown
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Seasonal variability of thermocline in the Yellow Sea 被引量:3
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作者 乔方利 夏长水 +3 位作者 施建伟 马建 葛人峰 袁业立 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2004年第3期299-305,共7页
Based on the MASNUM wave-tide-circulation coupled numerical model, seasonal variability of thermocline in the Yellow Sea was simulated and compared with in-situ observations. Both simulated mixed layer depth (MLD) and... Based on the MASNUM wave-tide-circulation coupled numerical model, seasonal variability of thermocline in the Yellow Sea was simulated and compared with in-situ observations. Both simulated mixed layer depth (MLD) and thermocline intensity have similar spatial patterns to the observations. The simulated maximum MLD are 8 m and 22 m, while the corresponding observed values are 13 m and 27 m in July and October, respectively. The simulated thermocline intensity are 1.2℃/m and 0.5℃/m in July and October,respectively, which are 0.6℃/m less than those of the observations. It may be the main reason why the simulated thermocline is weaker than the observations that the model vertical resolution is less precise than that of the CTD data which is 1 m. Contours of both simulated and observed thermocline intensity present a circle in general. The wave-induced mixing plays a key role in the formation of the upper mixed layer in spring and summer. Tidal mixing enhances the thermocline intensity. Buoyancy-driven mixing destroys the thermocline in autumn and keeps the vertical temperature uniform in winter. 展开更多
关键词 thennocline the Yellow Sea wave-tide-circulation coupled model wave-induced mixing tidalmixing
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Analysis of the dialectical relation between top coal caving and coal-gas outbtu rst 被引量:3
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作者 MENG Xian-zheng XIAYongjun +1 位作者 TANG Bing ZHANG Yong-jiang 《Journal of Coal Science & Engineering(China)》 2009年第2期181-187,共7页
According to the different engineering mechanical states of top coal caving andnormal stoping of gaseous loose thick coal seams,the dialectical relation between thiscaving method and dynamic disasters was analyzed by ... According to the different engineering mechanical states of top coal caving andnormal stoping of gaseous loose thick coal seams,the dialectical relation between thiscaving method and dynamic disasters was analyzed by simulating the change of stressstates in the process of top coal initial caving with different mining and caving ratios basedon the ANSYS10.0.The variation of elastic energy and methane expansion energy duringfirst top coal caving was analyzed by first weighting and periodic weighting and combiningwith coal stress and deformation distribution of top coal normal stoping as well as positiveand negative examples in top coal caving of outburst coal seam.The research shows thatthe outburst risk increases along with the increase of the caving ratio in the initial miningstage.In the period of normal stoping,when the mining and caving ratio is smaller than1:3 and hard and massive overlying strata do not exist (periodic weighting is not obvious),it is beneficial to control ground stress leading type outburst.Thus,it is unreasonable toprohibit top coal caving in dangerous and outburst prone areas. 展开更多
关键词 coal and gas outburst top coal initial caving mining and caving ratio ground stress
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Seasonal variation of the barrier layer in the PN section 被引量:1
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作者 张媛 吴德星 +1 位作者 林霄沛 山峰 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第2期192-201,共10页
In this paper, we use the conductivity-temperature-depth (CTD) observation data and a three-dimensional ocean model in a seasonally-varying forcing field to study the barrier layer (BL) in the PN section in the East C... In this paper, we use the conductivity-temperature-depth (CTD) observation data and a three-dimensional ocean model in a seasonally-varying forcing field to study the barrier layer (BL) in the PN section in the East China Sea (ECS). The BL can be found along the PN section with obviously seasonal variability. In winter, spring and autumn, the BL occurs around the slope where the cold shelf water meets with the warm Kuroshio water. In summer, the BL can also be found in the shelf area near salinity front of the Changjiang (Yangtze) River Dilution Water (YRDW). Seasonal variations of BL in the PN section are caused by local hydrological characteristics and seasonal variations of atmospheric forcing. Strong vertical convection caused by sea surface cooling thickens the BL in winter and spring in the slope area. Due to the large discharge of Changjiang River in summer, the BL occurs extensively in the shelf region where the fresh YRDW and the salty bottom water meet and form a strong halocline above the seasonal thermocline. The formation mechanism of BL in the PN section can be explained by the vertical shear of different water masses, which is called the advection mechanism. The interannual variation of BL in summer is greatly affected by the YRDW. In the larger YRDW year (such as 1998), a shallow but much thicker BL existed on the shelf area. 展开更多
关键词 the barrier layer the PN section the Changjiang (Yangtze) River KUROSHIO
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THE CLIMATIC CHARACTERISTICS OF SUMMER MONSOON ONSET OVER THE SOUTH CHINA SEA I.40-YEAR AVERAGE 被引量:1
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作者 冯瑞权 王安宇 +4 位作者 吴池胜 林建恒 古志明 林文实 谭志文 《Journal of Tropical Meteorology》 SCIE 2002年第1期10-19,共10页
By using 40-year NCEP reanalysis daily data (1958-1997), we have analyzed the climatic characteristics of summer monsoon onset in the South China Sea (105E ~ 120E, 5N ~ 20N, to be simplified as SCS in the text followe... By using 40-year NCEP reanalysis daily data (1958-1997), we have analyzed the climatic characteristics of summer monsoon onset in the South China Sea (105E ~ 120E, 5N ~ 20N, to be simplified as SCS in the text followed) pentad by pentad (5 days). According to our new definition, in the monsoon area of the SCS two of the following conditions should be satisfied: 1) At 850hPa, the southwest winds should be greater than 2m/s. 2) At 850 hPa, seq should be greater than 335K. The new definition means that the summer monsoon is the southwest winds with high temperature and high moisture. The onset of the SCS summer monsoon is defined to start when one half of the SCS area (105E ~ 120E,5N ~ 20N) is controlled by the summer monsoon. The analyzed results revealed the following: 1) The summer monsoon in the SCS starts to build up abruptly in the 4th pentad in May. 2) The summer monsoon onset in the SCS is resulted from the development and intensification of southwesterly monsoon in the Bay of Bengal. 3) The onset of the summer monsoon and establishment of the summer monsoon rainfall season in the SCS occur simultaneously. 4) During the summer monsoon onset in the SCS, troughs deepen and widen quickly in the lower troposphere of the India; the subtropical high in the Western Pacific moves eastward off the SCS in the middle troposphere; the easterly advances northward over the SCS in the upper troposphere. 展开更多
关键词 South China Sea summer monsoon ONSET climatic characteristics 40-year average
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Soil Geochemistry Changes Induced by a Foreign Soil Reconstruction Project in Three Gorges Reservoir Region of China 被引量:1
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作者 LIU Juan WEI Chao-Fu +1 位作者 LUO You-Jin DU Jing 《Journal of Mountain Science》 SCIE CSCD 2015年第6期1511-1520,共10页
Fertile topsoil was added onto the surface of barren slope land in Three Gorges Reservoir region of China in an anthropogenic process known as the foreign soil reconstruction project. The main goal of this paper was t... Fertile topsoil was added onto the surface of barren slope land in Three Gorges Reservoir region of China in an anthropogenic process known as the foreign soil reconstruction project. The main goal of this paper was to reveal the influence of anthropogenic activities on pedogenic processes and soil classifications. Chemical weathering indices and comparative analysis were applied to discuss changes in geochemical compositions and weathering features of purplish soils(Cambisols) before and after the project. Results showed that:(1) The foreign soil reconstruction project slightly altered the major element composition of topsoil and improved the soil structure. Although the distributions of major elements in the original topsoil, original subsoil, foreign topsoil and newly constructed topsoil were all similar to that in upper continental crust, newly constructed topsoil was the most similar soil.(2) The chemical index of alteration was more sensitive than the weathering index of Parker at indicating chemical weathering status of purplish soil. The chemical weathering status of newly constructed topsoil was higher than that of the original topsoil and lower than that of foreign topsoil.(3) Anthropogenic activities may provide a promising new thought for the anthropogenic soil classification system. The scope and subgroups of Anthrosols should be extended and strengthened. Or there may be a need to combine Anthrosols and Technosols orders to create a new soil order. The results may be used for optimizing soil mellowing engineering activities and enriching the soil classification system. 展开更多
关键词 Anthropogenic activities Weathering status Foreign soil reconstruction project Pedogenic processes Three Gorges Reservoir region China
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Daily Variability of Radon Gas in Brazilian Tropics Near Ground Level Surface 被引量:1
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作者 Inacio Malmonge Martin Marcelo Pego Gomes Bogos Nubar Sismanoglu Nicolas Cruvinel Lindo 《Journal of Environmental Science and Engineering(A)》 2015年第10期516-521,共6页
By monitoring the ionizing radiation from minute to minute in S^o Jos6 dos Campos, SP, Brazil (230 S, 450 W) using Geiger counter, during January to August 2015, it has confirmed the presence of radon gas in these m... By monitoring the ionizing radiation from minute to minute in S^o Jos6 dos Campos, SP, Brazil (230 S, 450 W) using Geiger counter, during January to August 2015, it has confirmed the presence of radon gas in these measures. The observation confirms the existence of a periodicity of 24 hours through the technique (Fast Fourier Transform) applied to the data set, and this cycle can be better visible in longer dry periods. On rainy days or with heavy fog in the region, this periodicity is modified or even disappears. As Geiger do not detect alpha particles due to absorption in the walls of the sensor tube, it measured X and gamma rays coming from the radon gas progeny. Radon gas (222Rn) has a half-life of 19.7 minutes to decays in 214Bi emitting gamma ray energy (45%) with 0.609 MeV which is monitored daily by Geiger. Also 222Rn decays in 26.8 minutes in 214pb giving (37%) with 0.35 MeV and others with less energy. It is confirmed the good performance ofa Geiger tube with LND 712 working with about 500 VDC rated voltage. 展开更多
关键词 GEIGER radon gas ionizing radiation.
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Hot deformation behavior and related microstructure evolution in Au−Sn eutectic multilayers 被引量:1
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作者 Yong MAO Dan-li ZHU +5 位作者 Jun-jie HE Chao DENG Ying-jie SUN Guang-jie XUE Heng-fei YU Chen WANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第6期1700-1716,共17页
Hot compression was performed on a multilayered Au−20Sn eutectic alloy to investigate the deformation behavior and microstructure evolution.During hot compression,microstructural spheroidization was initiated from pla... Hot compression was performed on a multilayered Au−20Sn eutectic alloy to investigate the deformation behavior and microstructure evolution.During hot compression,microstructural spheroidization was initiated from plastic instability regions,and it was preferentially activated in vertical lamellae with a growth direction parallel to the compressive direction.Continuous dynamic recrystallization associated with lattice dislocations was the mechanism in both AuSn and Au5Sn multilayers.After spheroidization,strain accumulations were weakened in both of the equiaxed phases,and the deformation mechanism was substantially replaced by grain boundary sliding and migration.Based on these findings,hot rolling was conducted on an as-cast Au−20Sn alloy and a foil with a thickness of~50μm was successfully prepared.The present study can promote the development of Au−20Sn foils,and provide insights into the deformation behavior and microstructure evolution of multilayered eutectic alloys. 展开更多
关键词 Au−20Sn eutectic alloy INTERMETALLICS hot compression multilayered structure deformation SPHEROIDIZATION
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Trend of Antarctic Ozone Hole and Its Influencing Factors 被引量:1
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作者 BIAN Lin-Gen LIN Zhong +2 位作者 ZHENG Xiang-Dong MA yong-Feng LU Long-Hua 《Advances in Climate Change Research》 2012年第2期68-75,共8页
Influencing factors, and variations and trends of Antarctic ozone hole in recent decades are analyzed, and sudden change processes of ozone at Zhongshan station and the effect of atmospheric dynamic processes on ozone... Influencing factors, and variations and trends of Antarctic ozone hole in recent decades are analyzed, and sudden change processes of ozone at Zhongshan station and the effect of atmospheric dynamic processes on ozone changes are also discussed by using the satellite ozone data and the ground-measured ozone data at two Antarctic stations as well as the NCEP/NCAR reanalysis data. The results show that equivalent effective stratospheric chlorine (EESC) and stratospheric temperature are two important factors influencing the ozone hole. The column ozone at Zhongshan and Syowa stations is significantly related with EESC and stratospheric temperature, which means that even though the two stations are both located on the edge of the ozone hole, EESC and stratospheric temperature still played a very important role in column ozone changes, and mean while verifies that EESC is applicable on the coast of east Antarctic continent. Decadal changes in EESC are similar with those of the ozone hole, and inter-annual variations of ozone are closely related with stratospheric temperature. Based on the relation of EESC and ozone hole size, it can be projected that the ozone hole size will gradually reduce to the 1980's level from 2010 to around 2070. Of course there might exist many uncertainties in the projection, which therefore needs to be further studied. 展开更多
关键词 Antarctic ozone hole equivalent effective stratospheric chlorine (EESC) stratospheric temperature TREND
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Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature 被引量:1
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作者 PENG Cheng FAN Ke DAI Haixia 《Atmospheric and Oceanic Science Letters》 CSCD 2019年第5期369-375,共7页
Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar... Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar region.After the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate periods.Period I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating downwards.In Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the troposphere.The anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over Eurasia.The zero line between negative and positive temperature anomalies moves southwards during days 5-20.Stratospheric cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole structure.During PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the troposphere.Specifically,a wave train is initiated from the North Atlantic region to northern Europe.The propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central Asia.Therefore,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period. 展开更多
关键词 Stratospheric polar vortex weak stratospheric polar vortex events in December subseasonal variability stratosphere-troposphere interaction winter Eurasian air temperature(0-40 days)
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Seasonal Patterns of Nitrogen and Phosphorus in the Litter and Soil Surface of Transitional Amazon Cerrado Forest, Brazil 被引量:1
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作者 J. de S. Nogueira L. Sanches +1 位作者 O.B. Pinto-Junior E.D. de Almeida 《Journal of Environmental Science and Engineering》 2011年第1期5-14,共10页
Measurements of litter production, and the surface litter pool were made over a 1 year period in a tropical transitional forest near Sinop, Mato Grosso Brazil with the aim of quantifying the seasonal variation of nitr... Measurements of litter production, and the surface litter pool were made over a 1 year period in a tropical transitional forest near Sinop, Mato Grosso Brazil with the aim of quantifying the seasonal variation of nitrogen and phosphorus in the litter and the annual contribution of nutrients to the soil. Average annual litterfall (+95% confidence interval (CI)) was 8.20 ton.ha^-1 year^-1 and forest floor litter mass was 58.63 ton'hal. Nitrogen and phosphorus in the forest floor litter mass was highest during the dry and dry-wet season, being 38% higher than in the wet and wet-dry season. Seasonal variation in the litter and concentration of nutrients was explained by seasonal variations in the climate, for example in the precipition and soil humidity. Average annual nitrogen and phosphorus concentrations in the forest floor mass were 17.24 ton.ha^-1 and 16.46 ton.ha^-1, respectively. The more significant forest floor mass fraction for returning soil nutrients was the leaves. The concentration of nutrients was higher in the soil superficial layer (at depths between 0-5 cm) than at depths between 30-70 cm, approximately 83% and 93% for total nitrogen and available phosphorus, respectively. 展开更多
关键词 Tropical forest litterpool nutrient cycling LITTERFALL
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Decadal variability of chlorophyll α in the South China Sea: a possible mechanism 被引量:1
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作者 刘汾汾 陈楚群 詹海刚 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第6期1054-1062,共9页
Four climatologies on a monthly scale (January, April, May and November) of chlorophyll a within the South China Sea (SCS) were calculated using a Coastal Zone Color Scanner (CZCS) (1979-1983) and the Sea-viewing Wide... Four climatologies on a monthly scale (January, April, May and November) of chlorophyll a within the South China Sea (SCS) were calculated using a Coastal Zone Color Scanner (CZCS) (1979-1983) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) (1998-2002). We analyzed decadal variability of chlorophyll a by comparing the products of the two observation periods. The relationships of variability in chlorophyll a with sea surface wind speed (SSW), sea surface temperature (SST), wind stress (WS), and mixed layer depth (MLD) were determined. The results indicate that there is obvious chlorophyll a decadal variability in the SCS. The decadal chlorophyll a presents distinct seasonal variability in characteristics, which may be as a result of various different dynamic processes. The negative chlorophyll a concentration anomaly in January was associated with the warming of SST and a shallower MLD. Generally, there were higher chlorophyll a concentrations in spring during the SeaWiFS period compared with the CZCS period. However, the chlorophyll a concentration exhibits some regional differences during this season, leading to an explanation being difficult. The deepened MLD may have contributed to the positive chlorophyll a concentration anomalies from the northwestern Luzon Island to the northeastern region of Vietnam during April and May. The increases of chlorophyll a concentration in northwestern Borneo during May may be because the stronger SSW and higher WS produce a deeper mixed layer and convective mixing, leading to high levels of nutrient concentrations. The higher chlorophyll a off southeastern Vietnam may be associated with the advective transport of the colder water extending from the Karimata Strait to southeastern Vietnam. 展开更多
关键词 South China Sea (SCS) decadal variability chlorophyll a
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VARIATION OF TOTAL OZONE IN LOWER LATITUDE AREA OF CHINA
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作者 张秀年 常有礼 +2 位作者 陈辉 郭世昌 孙正友 《Journal of Tropical Meteorology》 SCIE 2004年第2期171-177,共7页
By using the observational O3 data of Kunming and Hong Kong during the period of 1997 – 2001, the paper studies the distribution and variation of total ozone in low latitude region of China. The study shows that the ... By using the observational O3 data of Kunming and Hong Kong during the period of 1997 – 2001, the paper studies the distribution and variation of total ozone in low latitude region of China. The study shows that the characteristics of variation in Kunming and Hong Kong are very similar, and the total ozone in the western areas is larger than in the eastern ones. It is maximum in summer and minimum in winter. 展开更多
关键词 total ozone lower latitude characteristics of variation latitudinal difference
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POSITIVE INVERSION STRUCTURE OF THE CENTRAL STRUCTURE BELT IN TURPAN-HAMI BASIN 被引量:2
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作者 ZHU Wenbin , MA Ruishi, GUO Lingzhi, SUN Yan, XU Mingjie and HU Dezhao(Department of Earth Sciences, Nanjing University, Nanjing, JS 210093, China) 《Geotectonica et Metallogenia》 2003年第1期179-190,共12页
The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of str... The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall,and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event. 展开更多
关键词 Turpan-Hami Basin central structure belt growth fault positive inversion structure
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Application of waterborne acrylic emulsions in coated controlled release fertilizer using reacted layer technology 被引量:4
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作者 申亚珍 赵聪 +1 位作者 周健民 杜昌文 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第1期309-314,共6页
Waterborne acrylic emulsions modified with organic siloxanes and aziridine crosslinker were synthesized and applied as coating of controlled release fertilizer. The free films were characterized and the nutrient relea... Waterborne acrylic emulsions modified with organic siloxanes and aziridine crosslinker were synthesized and applied as coating of controlled release fertilizer. The free films were characterized and the nutrient release profiles of the coated fertilizers were determined. The results show that methyl silicone oil and methylsilanolate sodium could not improve water resistance performance and glass transition temperature Tgof coatings, while the firmness is enhanced. Aziridine crosslinker improves the water resistance performance, firmness and Tg. Incorporation of methyl silicone oil and aziridine crosslinker gives an excellent aqueous acrylic emulsion for coated controlled release fertilizer, with the 30-day cumulative nutrient release reduced to 16% and an estimated nutrient release duration over 190 days. Therefore, this waterborne coating is promising to meet the requirements for controlled release of nutrient and environmental protection. 展开更多
关键词 Controlled release fertilizer Acrylic emulsion SILOXANE CROSSLINKER Reacted layer technology
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Current situation of simultaneous coal and methane extraction tech- nology in pressure-relieved coalbed group
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作者 Feng CAI Ze-Gong LIU Yi LUO 《Journal of Coal Science & Engineering(China)》 2013年第4期500-506,共7页
The importance of simultaneous coal and methane extraction and its significance on green exploitation is stated, and current research situation of simultaneous coal and methane and faced new problems are introduced. T... The importance of simultaneous coal and methane extraction and its significance on green exploitation is stated, and current research situation of simultaneous coal and methane and faced new problems are introduced. The research progress on movement of overlying strata and stresses change in them, cracks development during mining in overlying strata and meth- ane emission under disturbance of mining as well as the changing rules of permeability and methane flow under the disturbance of mining is analyzed. The progress on practice of simultaneous coal and methane extraction is analyzed. The deficiencies of current research and further researching fields on simultaneous coal and methane extraction are pointed out. 展开更多
关键词 simultaneous coal and methane extraction pressure-relieved methane coalbed methane methane drainage
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