Variation characteristics of temperature and moisture content of seasonal frozen soil during freezing process in Changchun, China   总被引：1，自引：0，他引：1       下载免费PDF全文

WANG Qing  FAN Jianhua  FANG Ming  ZHANG Li 《世界地质(英文版)》2009,12(1):13-16

In China, seasonal frozen soil is widely distributed. The freezing damage of subgrade soil in Jilin Province has been one of major engineering geological problems troubling the safety of road, in which some common damage phenomena, such as frost heave, subsidence deformation and frost boiling, are all caused bywater translocation. Aiming at the phenomenon, the changes of moisture content of seasonal frozen soil in Changchun City are mainly studied by long-term field observation and indoor testing of physical properties under different conditions, and then the variation characteristics of moisture content in soil under different compactness and temperature conditions are realized. The results show that the increasing section of moisture content and negative temperature section all lie in 0.0-1.0 m of subgrade. Both lowest air and earth temperature occur in January to February, and the most negative temperature ranges from -7 ℃ to -10 ℃.  相似文献   

Effects of Dietary Carbohydrates Sources on Lipids Compositions in Abalone, Haliotis discus hannai Ino     

WANG Weifang  MAI Kangsen  ZHANG Wenbing  XU Wei  AI Qinghui  YAO Chunfeng  LI Huitao 《中国海洋大学学报(英文版)》2009,8(3)

A study was conducted to evaluate the effects of dietary carbohydrates on triglyceride, cholesterol and fatty acid concentrations in abalone, Haliotis discus hannai Ino. Six semi-purified diets with different carbohydrates (dextrin, heat-treated wheat starch, wheat starch, corn starch, tapioca starch and potato starch, respectively), all containing a carbohydrate level of 33.5%, were fed to abalone (initial shell length: 29.98 mm±0.09 mm; initial weight. 3.42 g±0.02 g) for 24 weeks in a recirculation system. The results indicate that serum triglyceride concentrations were significantly (P<0.05) higher in the abalone fed with dextrin, heat-treated wheat starch and wheat starch than those fed with corn starch, and serum cholesterol concentrations were significantly (P<0.05)higher in the abalone fed with dextrin, heat-treated wheat starch than those fed with corn starch. Fatty acid C20:4n-6 in the foot muscles were significantly (P<0.05) lower in the abalone fed with dextrin than those fed with wheat starch, corn starch, tapioca starch and potato starch. Fatty acid C20:4n-6 in hepatopancreas was significantly (P<0.05) lower in abalone fed with heat-treated wheat starch than those fed with corn starch, tapioca starch and potato starch. Fatty acid C22:6n-3 in the foot muscles were significantly (P< 0.05) lower in the abalone fed with dextrin and heat-treated wheat starch than those fed with wheat starch and potato starch.  相似文献   

渤海海峡老铁山水道动力地貌及演变研究   总被引：2，自引：0，他引：2  

刘建华  王庆  仲少云  杜国云  李春朋 《海洋通报》2008,27(1):68-74

老铁山水道位于渤海海峡北部,由南部冲刷槽、北部冲刷槽和中部隆起带等三个侵蚀地貌单元构成.在前人研究的基础上,通过搜集大量相关资料,对老铁山水道的动力条件、海底地貌、沉积物组成、峡道效应及地貌形成机制进行了综合分析研究.研究区海底地貌剖面图、沉积物组成和水道动力系统可为拟议中的渤海海峡跨海通道建设提供动力沉积学和动力地貌学依据.  相似文献   

微卫星技术路线的发展及在海洋生物中的应用   总被引：1，自引：0，他引：1  

高焕  于飞  阎斌论  陈建华  孔杰 《海洋湖沼通报》2008,(4)

微卫星技术是目前应用最广泛的分子标记技术之一,关于其技术路线也在不断的改进和更新,本文主要结合近年来海洋生物应用中的进展情况对此进行了阐述。微卫星技术路线主要涉及4个方面:微卫星位点的开发、引物设计与合成、结果检测和数据分析。在这4个方面,微卫星技术正朝着结果分析更精确和自动化分析等方向发展,同时也存在着一定的问题,本文对此进行了展望。  相似文献   

Long-term trend and fractal of annual runoff process in mainstream of Tarim River   总被引：14，自引：3，他引：11  

XU Jianhua CHEN Yaning LI Weihong DONG Shan 《中国地理科学(英文版)》2008,18(1):77-84

Based on the time series data from the Aral hydrological station for the period of 1958-2005, the paper reveals the long-term trend and fractal of the annual runoff process in the mainstream of the Tarim River by using the wavelet analysis method and the fractal theory. The main conclusions are as follows： 1） From a large time scale point of view, i.e. the time scale of 16 （24） years, the annual runoff basically shows a slightly decreasing trend as a whole from 1958 to 2005. If the time scale is reduced to 8 （23） or 4 （22） years, the annual runoff still displays the basic trend as the large time scale, but it has fluctuated more obviously during the period. 2） The correlation dimension for the annual runoff process is 3.4307, non-integral, which indicates that the process has both fractal and chaotic characteristics. The correlation dimension is above 3, which means that at least four independent variables are needed to describe the dynamics of the annual runoff process. 3） The Hurst exponent for the first period （1958-1973） is 0.5036, which equals 0.5 approximately and indicates that the annual runoff process is in chaos. The Hurst exponents for the second （1974-1989） and third （1990-2005） periods are both greater than 0.50, which indicate that the annual runoff process showed a long-enduring characteristic in the two periods. The Hurst exponent for the period from 1990 to 2005 indicates that the annual runoff will show a slightly increasing trend in the 16 years after 2005.  相似文献   

Vertical flux of particulate organic carbon in the central South China Sea estimated from 234Th-238U disequilibria     

马豪  曾志  何建华  陈立奇  尹明端  曾实  曾文义 《中国海洋湖沼学报》2008,26(4)

234Th-238u disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon (POC), 234Th (including both dissolved and particulate) and 238U in the water column at three stations were determined. The profiles of 234Th/238U activity ratio at the three stations all showed consistent 234Th deficit as compared to 238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate 234Th and a steady state box model, the dissolved 234Th scavenging rates, the particulate 234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol.m-2.d-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea.  相似文献   

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李松林  赖晓玲  何加勇  田建华 《大地测量与地球动力学》2008,28(5):16-20

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绿海龟外周血细胞显微结构与分类     

李长玲  曹伏君  黄翔鹄  刘楚吾  麦哲文 《广东海洋大学学报》2008,28(3)

对绿海龟(Chelonia mydas)外周血细胞的进行显微观察。结果表明,经Wright’s染液染色,可鉴定出红血细胞、单核细胞、淋巴细胞、血栓细胞、嗜酸性粒细胞、嗜碱性粒细胞、嗜中性粒细胞等七种血细胞。其中红血细胞数量多,长椭圆形,具圆核。白细胞数量少,多为圆形,分无颗粒型白细胞和颗粒型白细胞两种。无颗粒型白细胞包括单核细胞和淋巴细胞,细胞质中无特殊颗粒;颗粒型白细胞包括嗜酸性粒细胞、嗜碱性粒细胞和嗜中性粒细胞,细胞质中具有特殊颗粒。在白血细胞中,血栓细胞体积最小,单核细胞体积最大;在数量上,血栓细胞最多,淋巴细胞次之,单核细胞和嗜碱性粒细胞则较少。绿海龟的淋巴细胞可分为大淋巴细胞和小淋巴细胞两种类型。在外周血细胞中可观察到分解、解体状态的红血细胞,还可观察到少量未成熟的红血细胞和嗜中性粒细胞,偶尔可见正在分裂的红血细胞,提示红血细胞也可在外周血直接分裂。  相似文献   

华北地区强飑线的时空分布与发展移动特征     

方翀  麦子  关良 《气象科技》2023,51(3):388-396

基于2013—2017年华北地区的雷达组合反射率因子数据和雷暴大风观测数据,总共识别了27次强飑线过程,对27次强飑线过程的时空分布及发展移动特征进行了统计分析。结果表明,华北地区强飑线最集中的时间为7月下旬至8月上旬,强飑线最强的时次集中于16:00—22:00;强飑线形成前40 dBz回波起始位置最集中的区域为山西、内蒙古和河北3省交界处附近,强飑线形成位置多在京津冀境内;山西东部到河北西部沿山一带是最长长度达到400 km以上且维持时长超过7 h的强飑线形成位置集中区域;40 dBz回波起始时间为02:00—07:59的强飑线平均形成时长最长,14:00—19:59的强飑线平均形成时长最短;强飑线的最长长度与发展时长及维持时长有较好的对应关系;回波起始时间为14:00—19:59的强飑线形成期移动距离较短但发展期移动距离较长,而回波起始时间为02:00—07:59的强飑线则相反;大多数强飑线发展期的移动速度要快于形成期移动速度。  相似文献   

钱家店凹陷辉绿岩的时代、成因及对砂岩型铀成矿的制约     

杨东光  聂逢君  夏菲  巫建华  严兆彬  陈梦雅  刘晓博  王海涛  王常东 《大地构造与成矿学》2022,46(2):334-355

松辽盆地西南缘近年来铀找矿获得重要突破,预示着盆地蕴藏丰富的铀资源.而铀的成矿机理有待查明,尤其是矿床中广泛发育的辉绿岩,是否对成矿有改造作用,辉绿岩、反转构造及铀元素聚集之间的关系目前尚不十分清楚,制约了进一步找矿的思路.本文以钱家店凹陷钻孔辉绿岩为研究对象,通过对斜锆石和锆石U-Pb年代学、全岩岩石地球化学的研究,...  相似文献