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41.
Xin Li Dongliang Wang Baoquan Liu Chunling Ren Jianying Guo Xuefeng Su Jian Wang 《中国地球化学学报》2008,27(4):412-419
The northern margin of the Qaidam Basin is one of the main oil-gas exploration areas in western China, where source rocks are composed mostly of Middle and Lower Jurassic dark mud shale, carbargillite and coal. A large number of subsurface and outcrop samples differing in lithology with different types of organic matter were selected for resource evaluation, research and calculation. And among them, 13 samples were used for simulation experiment on hydrocarbon generating potential of various source rocks. At first, two kinds of heating modes were compared through simulation experiment, including single temperature-step heating and continual heating. Perhaps, the process of hydrocarbon generation and expulsion occurred naturally between a close system and an open system. In addition, the first heating mode was convenient, and all its reaction products were involved in the whole thermal evolution, and the final simulation experimental results were basically in consistency with the natural evolution trend Therefore, the first heating mode was adopted and the hydrocarbon yield of every sample was worked out. According to the type and lithology of organic matter and the hydrocarbon yield of samples for simulation experiment, hydrocarbon generation and expulsion mode with three kinds of lithology and five types of source rock has been established to provide the basis for hydrocarbon generation evaluation, research and resource calculation. 相似文献
42.
P V Rajesh S Pattnaik D Rai K K Osuri U C Mohanty S Tripathy 《Journal of Earth System Science》2016,125(3):475-498
In 2013, Indian summer monsoon witnessed a very heavy rainfall event (>30 cm/day) over Uttarakhand in north India, claiming more than 5000 lives and property damage worth approximately 40 billion USD. This event was associated with the interaction of two synoptic systems, i.e., intensified subtropical westerly trough over north India and north-westward moving monsoon depression formed over the Bay of Bengal. The event had occurred over highly variable terrain and land surface characteristics. Although global models predicted the large scale event, they failed to predict realistic location, timing, amount, intensity and distribution of rainfall over the region. The goal of this study is to assess the impact of land state conditions in simulating this severe event using a high resolution mesoscale model. The land conditions such as multi-layer soil moisture and soil temperature fields were generated from High Resolution Land Data Assimilation (HRLDAS) modelling system. Two experiments were conducted namely, (1) CNTL (Control, without land data assimilation) and (2) LDAS, with land data assimilation (i.e., with HRLDAS-based soil moisture and temperature fields) using Weather Research and Forecasting (WRF) modelling system. Initial soil moisture correlation and root mean square error for LDAS is 0.73 and 0.05, whereas for CNTL it is 0.63 and 0.053 respectively, with a stronger heat low in LDAS. The differences in wind and moisture transport in LDAS favoured increased moisture transport from Arabian Sea through a convectively unstable region embedded within two low pressure centers over Arabian Sea and Bay of Bengal. The improvement in rainfall is significantly correlated to the persistent generation of potential vorticity (PV) in LDAS. Further, PV tendency analysis confirmed that the increased generation of PV is due to the enhanced horizontal PV advection component rather than the diabatic heating terms due to modified flow fields. These results suggest that, two different synoptic systems merged by the strong interaction of moving PV columns resulted in the strengthening and further amplification of the system over the region in LDAS. This study highlights the importance of better representation of the land surface fields for improved prediction of localized anomalous weather event over India. 相似文献
43.
Expression of putative zinc-finger protein lcn61 gene in lymphocystis disease virus China (LCDV-cn) genome 总被引:1,自引:0,他引:1
An open reading frame (lcn61) of lymphocystis disease virus China (LCDV-cn), probably responsible for encoding putative zinc-finger proteins was amplified
and inserted into pET24a (+) vector. Then it expressed in E. coli BL21 (DE3), and His-tag fusion protein of high yield was obtained. It was found that the fusion protein existed in E. coli mainly as inclusion bodies. The bioinformatics analysis indicates that LCN61 is C2H2 type zinc-finger protein containing
four C2H2 zinc-finger motifs. This work provides a theory for functional research of lcn61 gene.
Supported by High Technology Research and Development Program of China (863 Program, No. 2006AA100309) 相似文献
44.
Environmental isotopic and hydrochemical study of water in the karst aquifer and submarine springs of the Syrian coast 总被引:1,自引:0,他引:1
The groundwater of major karst systems and submarine springs in the coastal limestone aquifer of Syria has been investigated using chemical and isotopic techniques. The δ18O values of groundwater range from ?6.8 to ?5.05‰, while those for submarine springs vary from ?6.34 to +1.08‰ (eastern Mediterranean seawater samples have a mean of +1.7‰). Groundwater originates from the direct infiltration of atmospheric water. Stable isotopes show that the elevation of the recharge zones feeding the Banyas area (400–600 m a.s.l.) is higher than that feeding the Amrit area (100–300 m a.s.l.). The 18Oextracted (18O content of the seawater contribution) for the major submarine springs suggests a mean recharge area elevation of 600–700 m a.s.l., and lower than 400 m a.s.l. for the spring close to Amrit. Based on the measured velocity and the percentage of fresh water at the submarine springs outlet, the estimated discharge rate is 350 million m3/year. The tritium concentrations in groundwater (1.6–5.9 TU) are low and very close to the current rainfall values (2.9–5.6 TU). Adopting a model with exponential time distribution, the mean turnover time of groundwater in the Al-sen spring was evaluated to be 60 years. A value of about 3.7 billion m3 was obtained for the maximum groundwater reservoir size. 相似文献
45.
We examined the anthropogenic and natural causes of flood risks in six representative cities in the Gangwon Province of Korea.
Flood damage per capita is mostly explained by cumulative upper 5% summer precipitation amount and the year. The increasing
flood damage is also associated with deforestation in upstream areas and intensive land use in lowlands. Human encroachment
on floodplains made these urban communities more vulnerable to floods. Without changes in the current flood management systems
of these cities, their vulnerability to flood risks will remain and may even increase under changing climate conditions. 相似文献
46.
Long records of monthly salinity observations along the axis of Chesapeake Bay, Delaware Bay, and Long Island Sound are used
to test a simple advection–dispersion model of the salt distribution in linearly tapered estuaries developed in a previous
paper. We subdivide each estuary into three to five segments, each with linear taper allowing a distributed input of fresh
water, and evaluate the dispersion in each segment. While Delaware Bay has weak dispersion and a classical sigmoidal salinity
structure, Long Island Sound and Chesapeake Bay are more dispersive and have relatively small gradients in the central stretches.
Long Island Sound is distinguished by having a net volume and salt flux out of its low-salinity end resulting in a smaller
range of salinity and increasing axial gradients at its head rather than the usual asymptotic approach to zero salinity. Estimates
of residence times based on model transport coefficients show that Long Island Sound has the most rapid response to fresh-water
flux variations. It also has the largest amplitude cycle in river discharge fluctuation. In combination, these cause the large
seasonal variation in the salinity structure relative to interannual variability in Long Island Sound as compared with Chesapeake
Bay and Delaware Bay. 相似文献
47.
48.
To better understand the movement and transport of water and pollution through the coarse gravel unsaturated zone, the presented
research was conducted to estimate water flow and transport processes with a tracing experiment in a lysimeter in the Selniška
Dobrava. A combined tracing experiment was performed with deuterated water and the fluorescent dye—uranine. The fastest and
dominant flow velocities were calculated based on injection time, the first tracer appearance time and the time of highest
concentration. Mean flow velocity and vertical dispersion were estimated by an analytical best-fit method using one-dimensional
convection–dispersion model. Deuterium was confirmed as an ideal conservative tracer and a more suitable tracer than dye (uranine)
for the study of water flow in the unsaturated zone of a coarse gravel aquifer. The retardation factor of the dye as compared
with deuterium was 1.13–1.75, which is in agreement with previously published results. Artificial tracers, especially deuterated
water, were also identified as a very useful tool to assess other properties and differences in water flow in the unsaturated
zone of a coarse gravel aquifer such as velocity and dispersion. 相似文献
49.
In unaltered volcanogenic massive sulfide (VMS) ore deposits, variable Rb/Sr ratios in the ore mineral permits application
of the Rb-Sr isotopic method to directly date the time of ore formation. In contrast, post-crystallization deformation and
metamorphism would open the system to metamorphic fluids that would alter elemental ratios. To test whether the Rb-Sr isotopic
systematics in the ore minerals had preserved the formation time in the ∼800 Ma metamorphosed VMS ores within the ∼1 Ga Ambaji-Sendra
arc terrain, Rajasthan, NW India, common sulfides, pyrite and sphalerite from the Pipela Cu-Zn prospect, were analyzed for
their geochemistry and Rb-Sr isotopic systematics. Trace and rare earth elements in these minerals are resident probably at
crystal defects, whereas all inclusions (including those from metamorphic fluids) were removed by a simple crush leach method.
Results of direct dating by the Rb-Sr method to the hydrothermal pyrite yielded an isochron age of 1025±76 Ma with an initial
Sr ratio of 0.7051±0.0006, similar to previously determined zircon U-Pb age of 987 Ma from associated rhyolites. This suggests
the applicability of the crush leach method to date formation time of metamorphosed pyrite ores. 相似文献
50.
Hanne M. L. Kvitsand Mette Myrmel Liv Fiksdal Stein W. Østerhus 《Hydrogeology Journal》2017,25(5):1257-1269
Two case studies were carried out in central Norway in order to assess the performance of bank filtration systems in cold-climate fluvial aquifers relying on recharge from humic-rich surface waters with moderate microbial contamination. Three municipal wells and two surface-water sources at operative bank filtration systems were monitored for naturally occurring bacteriophages, fecal indicators, natural organic matter (NOM) and physico-chemical water quality parameters during a 4-month period. Aquifer passage effectively reduced the microorganism and NOM concentrations at both study sites. Bacteriophages were detected in 13 of 16 (81%) surface-water samples and in 4 of 24 (17%) well-water samples, and underwent 3 ± 0.3 log10 reduction after 50–80-m filtration and 20–30 days of subsurface passage. NOM reductions (color: 74–97%; dissolved organic carbon: 54–80%; very hydrophobic acids: 70%) were similar to those achieved by conventional water-treatment processes and no further treatment was needed. Both groundwater dilution and sediment filtration contributed to the hygienic water quality improvements, but sediment filtration appeared to be the most important process with regard to microbial and NOM reductions. A strengths-weaknesses-opportunities-threats analysis showed that bank filtration technology has a high potential as a pretreatment method for the provision of hygienically safe drinking water in Norway. 相似文献