Inflation in Bianchi type-IX Einstein-Cartan Cosmological Model     

K.H. Kong  P.C.H. Cheung  H.Q. Lu  K.S. Cheng 《Astrophysics and Space Science》1998,260(4):521-529

Within the framework of Einstein-Cartan theory with Weyssenhoff fluid, we investigate an inflation model for an anisotropic Bianchi type-IX cosmological model. The system of field equations is solved numerically and an inflation epoch is achieved. The general condition for the inflation to occur is also discussed. This anisotropic model evolves quickly towards to an isotropic one.  相似文献   

塔里木盆地塔中地区奥陶系碳酸盐岩储层空隙研究   总被引：11，自引：0，他引：11  

孔金平  刘效曾 《矿物岩石》1998,18(3):25-33

空隙是构成碳酸盐岩储层的基本单元,空隙发育史对应了成岩演化史,且不同类型空隙的储层具有不同的分布规律。塔里木盆地塔中地区奥陶系碳酸盐岩储层的空隙可以分为６类２１种,以裂缝—孔洞型为主,礁、丘、滩相碳酸盐岩、中—细晶白云岩与古岩溶和构造岩溶的复合区为有利空隙发育带,也是风化壳型油气藏和内幕型油气藏的有利储集相带。  相似文献   

The Complete Sequence of Mitochondrial COⅡ Gene of Fenneropenaeus chinensis and Its Applicability as a Marker for Phylogenetic Analysis     

YU Shanshan KONG Xiaoyu LI Yulong XU Hui 《中国海洋大学学报(英文版)》2007,6(2):187-192

The complete mitochondrial cytochrome oxidase subunit Ⅱ （COⅡ） gene of Penaeinae shrimp Fenneropenaeus chinensis was cloned and sequenced. The gene is 688 bp in length and codes for 229 amino acids. It shows 83.2%, 87.0% and 83.8% sequence similarity to Marsupenaeus Japonicus, Penaeus monodon and Farfantepenaeus notialis, respectively. The A＋T content of the whole gene and that at the third position of codons are 64.7% and 78.2%, respectively. The phylogenetic relationship between F. chinensis and three other species representing genera Farfanatepenaeus, Marsupenaeus and Penaeus was analyzed. Results showed that the genetic distances among the four taxa ranged from 0.144 0 to 0.200 5, exceeding those estimated with COⅠ and partial 16S rRNA gene sequences among Marsupenaeus, Litopenaeus and Melicertus, and being therefore larger than the value among subgenera. It has been suggested that the COⅡ gene has a faster evolutionary rate than that of the COⅠ gene and partial 16S rRNA gene and could be used for phylogenetic analysis at genus or species level. The results of the present study indicated that Farfantepenaeus, Fenneropenaeus, Marsupenaeus and Penaeus are at a higher phylogenetic level than subgenus, which supports the opinion of the elevation of phylogenetic status of the four subgenera to genus level.  相似文献   

Holocene climate events inferred from modern and fossil pollen records in Butuo Lake,Eastern Qinghai–Tibetan Plateau     

Yun Zhang  Zhaochen Kong  Qi-Bin Zhang  Zhenjing Yang 《Climatic change》2015,132(2):223-235

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Evaluation of radar and automatic weather station data assimilation for a heavy rainfall event in southern China     

Tuanjie Hou  Fanyou Kong  Xunlai Chen  Hengchi Lei  Zhaoxia Hu 《大气科学进展》2015,32(7):967-978

To improve the accuracy of short-term(0–12 h) forecasts of severe weather in southern China, a real-time storm-scale forecasting system, the Hourly Assimilation and Prediction System(HAPS), has been implemented in Shenzhen, China. The forecasting system is characterized by combining the Advanced Research Weather Research and Forecasting(WRF-ARW)model and the Advanced Regional Prediction System(ARPS) three-dimensional variational data assimilation(3DVAR) package. It is capable of assimilating radar reflectivity and radial velocity data from multiple Doppler radars as well as surface automatic weather station(AWS) data. Experiments are designed to evaluate the impacts of data assimilation on quantitative precipitation forecasting(QPF) by studying a heavy rainfall event in southern China. The forecasts from these experiments are verified against radar, surface, and precipitation observations. Comparison of echo structure and accumulated precipitation suggests that radar data assimilation is useful in improving the short-term forecast by capturing the location and orientation of the band of accumulated rainfall. The assimilation of radar data improves the short-term precipitation forecast skill by up to9 hours by producing more convection. The slight but generally positive impact that surface AWS data has on the forecast of near-surface variables can last up to 6–9 hours. The assimilation of AWS observations alone has some benefit for improving the Fractions Skill Score(FSS) and bias scores; when radar data are assimilated, the additional AWS data may increase the degree of rainfall overprediction.  相似文献   

环渤海葡萄涝渍指标构建及风险评估          下载免费PDF全文

毛红丹  霍治国  张蕾  杨建莹  孔瑞  李春晖  江梦圆 《应用气象学报》2022,33(1):92-103

以中国环渤海地区葡萄主产区为研究对象,利用1980-2019年研究区域内303个气象站逐日气象资料、葡萄发育期资料和葡萄涝渍灾情资料,基于相对湿润度方法构建葡萄逐日涝渍指数M5i,以历史灾情反演和灾变过程解析为主线,采用正态分布的Lilliefors检验和t分布区间估计等方法,构建适用于中国环渤海地区葡萄主产区的葡萄涝...  相似文献   

Reclamation-oriented spatiotemporal evolution of coastal wetland along Bohai Rim,China     

Fan Wei  Mei Han  Guangxuan Han  Min Wang  Lixin Tian  Jiqian Zhu  Xianglun Kong 《海洋学报(英文版)》2022,41(9):192-204

Coastal wetlands are located in the ecotone of interaction between the land surface and sea, and anthropogenic activities extensively interfere with these wetlands through the reclamation of large tidal wetlands and destruction of the function of the ecosystems. In this study, we investigated the dynamic evolutionary characteristics of the Bohai Rim coastal area over the past 40 years using the Modified Normalized Difference Water Index, the fractal dimension, object-oriented classification, the land-use transfer trajectory, and regression analysis. Additionally, we quantified and monitored the evolution of reclamation and analyzed the correlation between reclamation and coastal wetlands based on 99 Landsat-2, -5, and -8 images (at 60 m and 30 m spatial resolution) over the period 1980–2019. The results are as follows. (1) The coastline of the Bohai Rim increased by 1 631.2 km from 1980 to 2019 with a zigzag variation. The artificial coastline increased by 2 946.1 km, whereas the natural coastline decreased by 90%. (2) The area of man-made wetlands increased by 3 736.9 km2, the area of construction land increased by 1 008.4 km2, and the natural wetland area decreased by 66%. The decrease of tidal flats is the main contributor to the decrease of natural wetland area (takes account for 91.1%). Coastal areas are affected by intense human disturbance, which was taken place across a large area of tidal flats and caused the landscape to fragment and be more heterogeneous. The coastal zone development activities were primarily concentrated in the southern Laizhou Bay, the Yellow River Delta, the Bohai Bay, the northern Liaodong Bay, and the Pulandian Bay. The solidified shorelines and increase in sea level have resulted in intertidal wetlands decreasing and impaired wetland ecology. (3) There is a good agreement between reclamation and the size of the coastal wetlands. Both land reclamation and the reduction in coastal wetland areas are significantly related to the population size, fishery output value, and urbanization rate. In summary, human activities, such as the construction of aquaculture ponds and salt pans, industrialization, and urbanization, are the primary forces that influence the environmental changes in the coastal region. This study is beneficial for establishing and improving the systems for the rational development and utilization of natural resources, and provides theoretical references for restoring wetland ecology and managing future reclamation activities in other coastal zone-related areas.  相似文献   

Climate Change Adaptation in Southeast Asia. Joy Jacqueline Pereira,Mohd Khairul Zain and Rajib Shaw  (eds). Springer Nature Singapore Pte Ltd,Singapore, 2021, pp. xv + 233. ISBN 978-9-811-66087-0 (hbk).     

Feng Kong 《Singapore journal of tropical geography》2023,44(3):563-566

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The formation of wind curl in the marine atmosphere boundary layer over the East China Sea Kuroshio in spring     

Suping Zhang  Yang Kong 《中国海洋大学学报(英文版)》2014,13(6):883-892

Various data are used to investigate the characteristics of the surface wind field and rainfall on the East China Sea Kuroshio (ESK) in March and April, 2011. In March, the wind speed maximum shows over the ESK front (ESKF) in the 10 meter wind field, which agrees with the thermal wind effect. A wind curl center is generated on the warm flank of the ESKF. The winds are much weaker in April, so is the wind curl. A rainband exists over the ESKF in both the months. The Weather Research and Forecasting (WRF) model is used for further researches. The winds on the top of the marine atmosphere boundary layer (MABL) indicate that in March, a positive wind curl is generated in the whole MABL over the warm flank of the ESKF. The thermal wind effect forced by the strong SST gradient overlying the background wind leads to strong surface northeasterly winds on the ESKF, and a positive shearing vorticity is created over the warm flank of the ESKF to generate wind curl. In the smoothed sea surface temperature experiment, the presence of the ESKF is responsible for the strong northeast winds in the ESKF, and essential for the distribution of the rainfall centers in March, which confirms the mechanism above. The same simulation is made for April, 2011, and the responses from the MABL become weak. The low background wind speed weakens the effect of the thermal wind, thus no strong Ekman pumping is helpful for precipitation. There is no big difference in rainfall between the control run and the smooth SST run. Decomposition of the wind vector shows that local wind acceleration induced by the thermal wind effect along with the variations in wind direction is responsible for the pronounced wind curl/divergence over the ESKF.  相似文献   

Analysis of genetic diversity and differentiation of seven stocks of Litopenaeus vannamei using microsatellite markers     

Kai Zhang  Weiji Wang  Weiya Li  Quanqi Zhang  Jie Kong 《中国海洋大学学报(英文版)》2014,13(4):647-656

Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.  相似文献