An Initial Research on the Geometric Theory of Quasicrystal Structures     

Chen Jingzhong Wan Anwa Lou Xiangyu Zhao Wenxia Liu XiangwenChina University of Geosciences  Wuhan 《中国地质大学学报(英文版)》1992

  相似文献   

Undifferenced Cycle Slip Estimation of Triple-Frequency BeiDou Signals with Ionosphere Prediction     

Bofeng Li  Yanan Qin  Zhen Li  Lizhi Lou 《Marine Geodesy》2016,39(5):348-365

With the rapid development of BeiDou satellite navigation system (BDS), high-quality service has been provided in the Asia-Pacific region currently, which will be extended to the whole world very soon. BDS is the first Global Navigation Satellite System that all satellites broadcast the triple-frequency signals. The triple-frequency signals in theory can improve the cycle slip detection that is one of the preconditions in precise positioning by making use of carrier phase. This paper discusses the development of a cycle slip detection method for undifferenced BDS triple-frequency observations in kinematic scenario. In this method, two geometry-free extra-wide-lane combinations and one geometry-free narrow-lane (NL) combinations are employed. The key is to mitigate the between-epoch ionospheric biases in the geometry-free NL combinations. We propose to predict the ionospheric biases of current epoch by using those from its consecutive foregoing epochs. The method is tested with extensive experiments in varying observation scenarios. The results show that in case of sampling interval as small as 5 s, the between-epoch ionospheric biases can be ignored and the correct cycle slips can be determined. Meanwhile in case of lower sampling frequency, one needs to compensate the ionospheric biases of current epoch by using the predicted ionospheric biases. The presented method can correctly detect all cycle slips even if they are as small as 1 cycle.  相似文献   

温度对小黄鱼体内抗氧化酶及消化酶活性的影响   总被引：1，自引：0，他引：1  

刘峰  刘阳阳  楼宝  陈睿毅  詹伟  徐麒翔  马涛  徐冬冬  王立改  毛国民 《海洋学报》2016,38(12):76-85

为了深入了解不同温度条件下小黄鱼的应激反应,为小黄鱼的人工养殖提供参考。本次研究以人工繁殖的4.5月龄小黄鱼为研究对象,采用不同水温（27℃、29℃、31℃、32℃、33℃）进行养殖,以此确定小黄鱼的高温致死温度,并检测不同养殖水温条件下小黄鱼肝脏和肠道中抗氧化酶（超氧化物歧化酶SOD、过氧化氢酶CAT）和消化酶（脂肪酶LPS、淀粉酶AMS）的活性,比较小黄鱼不同组织中4种酶活性的变化情况。结果显示,32℃的养殖水温为小黄鱼的初始致死温度;养殖温度对小黄鱼肝脏和肠道中几种酶的活性均存在显著影响（P<0.05）:抗氧化酶和消化酶活性均随着养殖水温的升高呈现先升高后下降的趋势（除了肠道中的CAT）。另外,肝脏中抗氧化酶活性强于消化酶,而肠道中则相反,表明肝脏侧重于机体免疫反应,而肠道更侧重于食物消化。通过二次项回归方程拟合了温度与酶活性的回归方程,只有肝脏和肠道中的LPS活性与温度的回归方程有意义,决定系数r2分别为0.89和0.93（在0.85以上）。此外,肝脏中LPS活性与实验鱼体质量呈极显著正相关关系（P<0.01）,研究结果为小黄鱼专用配合饲料的研发提供了重要参考。研究还得出,养殖水温29℃和31℃时,进行小黄鱼养殖可取得较好效果,研究结果可为小黄鱼快速养成提供指导。  相似文献   

Radiative effects on torrential rainfall during the landfall of Typhoon Fitow (2013)     

Lingyun Lou  Xiaofan Li 《大气科学进展》2016,33(1):101-109

Cloud microphysical and rainfall responses to radiative processes are examined through analysis of cloud-resolving model sensitivity experiments of Typhoon Fitow(2013) during landfall.The budget analysis shows that the increase in the mean rainfall caused by the exclusion of radiative effects of water clouds corresponds to the decrease in accretion of raindrops by cloud ice in the presence of radiative effects of ice clouds,but the rainfall is insensitive to radiative effects of water clouds in the absence of radiative effects of ice clouds.The increases in the mean rainfall resulting from the removal of radiative effects of ice clouds correspond to the enhanced net condensation.The increases(decreases) in maximum rainfall caused by the exclusion of radiative effects of water clouds in the presence(absence) of radiative effects of ice clouds,or the removal of radiative effects of ice clouds in the presence(absence) of radiative effects of water clouds,correspond mainly to the enhancements(reductions) in net condensation.The mean rain rate is a product of rain intensity and fractional rainfall coverage.The radiation-induced difference in the mean rain rate is related to the difference in rain intensity.The radiation-induced difference in the maximum rain rate is associated with the difference in the fractional coverage of maximum rainfall.  相似文献   

Variations of winter precipitation over southeastern China in association with the North Atlantic Oscillation          下载免费PDF全文

Maoyuan Lou  Chao Li  Shifeng Hao  Juan Liu 《Acta Meteorologica Sinica》2017,31(3):476-489

The synoptic-scale winter precipitation variations over southeastern China (22°–32°N, 105°–125°E) and their association with the North Atlantic Oscillation (NAO) during 1951–2007 are investigated in this paper. The variability of wintertime precipitation is characterized by meridional displacement of its maximum center. Two precipitation regimes, with maximum centers located over the Yangtze and Pearl River basins, are identified via cluster analysis. Time-lagged analyses suggest that the two precipitation regimes are connected with the decaying phases of positive NAO (NAO+) events of different amplitudes. A strong (medium) NAO+ event is defined as one when the maximum amplitude of the NAO index exceeds 1.0 (in the range of 0.7–1.0) for at least 4 consecutive days and drops to less than 0.3 within 7 days following the peak index. After the peak of a strong NAO+, southerly winds expand northward to the Yangtze River (about 30°N), a northeast–southwest-tilted trough migrates to east of Lake Baikal, and cold air intrudes into central eastern China; thus, precipitation is strengthened over the Yangtze River basin where warm and cold air masses converge. In comparison, during the decaying phase of medium NAO+ events, the southerly winds are relatively weak, and precipitation tends to be enhanced at lower latitudes (around 25°N). Further analysis indicates that downstream Rossby-wave propagation may account for the latitudinal expansion of the southerly wind anomalies over the eastern coastal area of China during the decaying phase of NAO+ events of different strengths.  相似文献   

Application of desingularized approach to water wave propagation over three-dimensional topography   总被引：1，自引：0，他引：1  

X.T. Zhang  B.C. Khoo  J. Lou 《Ocean Engineering》2007,34(10):1449-1458

A numerical approach based on desingularized boundary element method and mixed Eulerian–Lagrangian formulation [Zhang et al., 2006. Wave propagation in a fully nonlinear numerical wave tank: a desingularized method. Ocean Engineering 33, 2310–2331] is extended to solve the water wave propagation over arbitrary topography in a three-dimensional wave tank. A robust damping layer applicable for regular and irregular incident waves is employed to minimize the outgoing wave reflection back into the wave tank. Numerical results on the propagation of regular and irregular incident waves over the flat bottom and linear incident waves over an elliptical shoal show good concurrence with the corresponding analytical solutions and experimental data.  相似文献   

鳀鱼蛋白酶水解物的营养评价   总被引：4，自引：0，他引：4  

刘洋  王长云  薛长湖  楼伟凤  陈修白 《中国海洋大学学报(自然科学版)》1996,(1)

对鱼蛋白酶水解物EAPH进行评价。EAPH蛋白质含量88．26％，氨基酸比例会理，必需氨基酸占总氨基酸43．61％，并含丰富的水溶性维生素和微量元素。EAPH对动物的生长效果、饲料效率（FE）、蛋白质效率（PER）、净蛋白质效率（NPR）均与对照乳粉蛋白相近；表征其消化吸收利用率的其消化率（TD）、生物价（BV）、蛋白质净利用率（NPU）均略高于对照乳粉蛋白；小麦粉蛋白经EAPH强化后，其蛋白质消化吸收利用率大幅度提高。EAPH为优良蛋白制品。  相似文献   

On hydraulic falls of two-layer flow     

Xu Zhaoting  Lou Shunli  Tian Jiwei  Samuel Shan pu Shen 《海洋学报(英文版)》1996,15(2):179-191

Ｏｎｈｙｄｒａｕｌｉｃｆａｌｌｓｏｆｔｗｏ－ｌａｙｅｒｆｌｏｗ￥ＸｕＺｈａｏｔｉｎｇ;ＬｏｕＳｈｕｎｌｉ;ＴｉａｎＪｉｗｅｉａｎｄＳａｍｕｅｌＳｈａｎｐｎＳｈｅｎ（ＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃａｌＤｅｅａｎｏｐａｐｈｙａｎｄＰｈｙｓｉｃａｌｏｃ...  相似文献   

几种河口生物对天津市污水及其若干组分的回避反应     

吴玉霖  崔可铎  赵鸿儒  侯兰英  娄清香 《海洋科学集刊》1988,(29):159-168

综合污水包括工业废水、生活污水和农业废水(含化肥、农药等)。据统计，每年排人渤海湾的工业废水达5.28亿吨，生活污水1.4亿吨，它们绝大部分经排污河汇流人海，造成了河口海域的污染。 鱼类等海洋生物具有敏锐的嗅觉和味觉，在体表上亦分布有许多化学感受器，能够感知许多低浓度的化学物质，并发生回避反应，这是海洋生物对水环境污染的一种保护性反应。我们利用梭鱼Mugil so-iuy、鲈鱼Lateolabrax japonicus、罗非鱼Tilapia mossambica和对虾Penaeus orientalis等几种河口生物对天津市南、北排污河综合污水及其主要有机污染物的回避反应进行了试验研究，探讨综合污水及其几种主要有毒组分对海洋生物的毒性效应，为海域环境管理提供科学依据。  相似文献   

烟台、威海南部近岸海域物理自净能力研究——Ⅱ.拉格朗日余流模型     

娄安刚  石磊  赵可胜 《中国海洋大学学报(自然科学版)》1994,(Z1)

在该海域潮流计算的基础上,利用有限元法建立了二维的拉格朗日余流模型,得出了威海及烟台南部海域的拉格朗日余流分布。跟踪了文登、乳山、海阳、莱阳近岸主要排污口的污水输运轨迹,为沿岸县市污水排放的选址提供理论依据。  相似文献