奶牛隐性乳房炎发生规律探讨   总被引：2，自引：0，他引：2  

苏俊强  王建亮  梁海锋  窦建翠  王运新  车振华 《广东海洋大学学报》2002,22(6):65-68

通过对某奶牛场泌乳牛群隐性乳房炎的调查和分析 ,研究了奶牛隐性乳房炎的发生规律。结果表明 ,该场奶牛隐性乳房炎的阳性率为 31.4 2 %、乳区临诊阳性率达到 10 .6 0 % ;隐性乳房炎的发生随着胎次和泌乳时间的增加而增加 ;左乳区阳性率高于右侧 ,前乳区高于后乳区。在牛群(场 )里进行经常性的临床和实验室检验是必要的。  相似文献   

Parallel viewshed analysis on a PC cluster system using triple-based irregular partition scheme     

Xiao-Dong?Song  Guo-An?TangEmail author  Xue-Jun?Liu  Wan-Feng?Dou  Fa-Yuan?Li 《Earth Science Informatics》2016,9(4):511-523

Using digital elevation models (DEMs), viewshed analysis algorithms determine the visibility of each point on the terrain at a given location in space. As a data-parallel algorithm, real-time viewshed analysis from grid DEM poses a practical challenge to personal computer (PC) users, particularly when dealing with higher resolution and accuracy of large terrain data. Therefore, this paper presents a universal domain decomposition algorithm based on an equal-area strategy for the parallel viewshed analysis on a PC cluster system. The approach uses a scan-line filling method for data partitioning of the irregular bounding polygon of the terrain. The terrain data are divided into sectors of the same area that are connected by the viewpoint and the region vertices, ignoring the null value (or NODATA) points. Furthermore, each sector is assigned to one processor and is organized in the form of triples composed of location and elevation at one point. An index of triples is built to store all of the locations of terminal vertices row-by-row and thus the random access of any point is achieved by using the offsets in each row. Two commonly applied viewshed algorithms, namely, “reference plane” and “Xdraw” algorithms are employed to verify the performance. In addition, two experiments focus on evaluating the efficiency performance and comparing traditional implementation, respectively. Experimental results demonstrate a significant performance improvement compared with the sequential computing method. The memory usage gradually decreases as the number of processors increases. Based on the equal-area decomposition, partitions in terms of sectors can guarantee a suitable load balance. Additional benefits of the proposed solution also include high storage efficiency and program portability.  相似文献   

Assessment of vertical TEC mapping functions for space-based GNSS observations   总被引：1，自引：1，他引：0  

Jiahao Zhong  Jiuhou Lei  Xiankang Dou  Xinan Yue 《GPS Solutions》2016,20(3):353-362

The mapping function is commonly used to convert slant to vertical total electron content (TEC) based on the assumption that the ionospheric electrons concentrate in a layer. The height of the layer is called ionospheric effective height (IEH) or shell height. The mapping function and IEH are generally well understood for ground-based global navigation satellite system (GNSS) observations, but they are rarely studied for the low earth orbit (LEO) satellite-based TEC conversion. This study is to examine the applicability of three mapping functions for LEO-based GNSS observations. Two IEH calculating methods, namely the centroid method based on the definition of the centroid and the integral method based on one half of the total integral, are discussed. It is found that the IEHs increase linearly with the orbit altitudes ranging from 400 to 1400 km. Model simulations are used to compare the vertical TEC converted by these mapping functions and the vertical TEC directly calculated by the model. Our results illustrate that the F&K (Foelsche and Kirchengast) geometric mapping function together with the IEH from the centroid method is more suitable for the LEO-based TEC conversion, though the thin layer model along with the IEH of the integral method is more appropriate for the ground-based vertical TEC retrieval.  相似文献   

Microseismic Precursory Characteristics of Rock Burst Hazard in Mining Areas Near a Large Residual Coal Pillar: A Case Study from Xuzhuang Coal Mine,Xuzhou, China     

An-ye Cao  Lin-ming Dou  Chang-bin Wang  Xiao-xiao Yao  Jing-yuan Dong  Yu Gu 《Rock Mechanics and Rock Engineering》2016,49(11):4407-4422

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江西相山铀矿田构造控矿规律研究   总被引：4，自引：0，他引：4  

窦小平 《地质与勘探》2015,51(5):879-887

对江西相山铀矿田内断裂构造格架及火山构造特征做了研究,认为相山火山盆地和断裂构造的成生与发育受永丰-抚州深断裂演化控制。从构造控矿作用看,相山铀矿田受大型中心式塌陷火盆控制,北部的EW向断裂带和中西部的EW向构造断陷带控制着矿田内的矿集带,NE向与EW向断裂构造复合部位控制了矿床的位置,密集成群的断裂裂隙带控制着铀矿体,使各矿床中的铀矿体呈群脉型。这些铀矿田地质构造特征及控矿规律对进一步找矿具有重要的指导意义。  相似文献   

Quantitative analysis of seismic velocity tomography in rock burst hazard assessment   总被引：5，自引：1，他引：4  

Wu Cai  Linming Dou  Siyuan Gong  Zhenlei Li  Shasha Yuan 《Natural Hazards》2015,75(3):2453-2465

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天津地区三次低涡暴雨过程的诊断分析     

王万筠  殷海涛  窦策伟  王宏  庄庭 《气象与环境科学》2019,42(3):42-50

利用地面实况资料及NCEP再分析资料(1°×1°),选取2016年、2010年及2011年发生在天津市的3次强降水天气过程,分析其天气形势及水汽条件,并应用湿位涡理论对3次暴雨天气进行了诊断分析。分析结果表明:3次暴雨过程均发生在典型的东高西低的环流形势下,低空低涡是主要的影响系统之一。低涡的动力结构及水汽条件的差异对应不同的降水强度。正涡度区强度越强、维持时间越长,降水强度越大。2016年过程水汽通量散度明显强于另两次过程的,与其降水强度相匹配。湿位涡的时空演变可以很好地描述天津地区暴雨的发生发展。天津上空MPV_1负值区标志着不稳定能量的急剧增加,MPV_1负值区出现在降水发生前3 h至6 h,提前预示了天津地区暴雨天气的发生。MPV_1正值区对应强降水的区域。过程降水前MPV_2绝对值的激增,表明大气的斜压性增强,有利于气旋性涡度发展。MPV_2绝对值的激增基本同步于降水的发生。  相似文献   

深穿透地球化学勘查技术对隐伏稀有金属矿的勘查指示：以甲基卡X03号锂矿脉为例     

鲁岳鑫  张必敏  刘汉粮  迟清华  窦备  刘福田  王强  谢明君  呼延钰莹 《地质学报》2023,97(1):291-305

花岗伟晶岩型锂矿是锂资源的重要矿产类型,目前随着勘查程度的提高,发现地表出露的伟晶岩型锂矿资源的几率越来越小,下一步的勘查重点应放到找寻隐伏型锂矿资源。近年来,深穿透地球化学勘查手段在隐伏矿勘查中发挥了重要作用。其中土壤微细粒分离测量技术能有效探测深部异常信息,已在多种景观覆盖区进行了试验,并取得了显著的效果。本文以四川甲基卡X03号隐伏锂矿脉为研究对象,利用土壤微细粒分离测量技术,开展深穿透地球化学勘查技术对隐伏锂矿脉探测的试验研究,并分析了成矿及伴生元素组合特征,结果表明：Li、Be、Rb、Cs、Sn、Nb、Ta、Bi、Pb、U等元素具有较好的相关性,富集程度高,异常明显,异常峰值显著;其中,Li-Be-Bi-Cs-Rb-Pb-U元素组合与研究区X03号矿脉成矿元素组合具有良好的耦合性;利用土壤微细粒分离测量技术取得的元素高异常范围与已知隐伏矿体具有较好的对应关系,可以将上述元素作为该区域寻找锂矿的指示元素。以上结果证实了深穿透地球化学勘查技术能有效指示深部隐伏锂矿体,可以将深穿透地球化学勘查技术应用于西部高寒山区景观覆盖区地球化学找矿勘查中。  相似文献   

Food habits and seasonal variation of stomach contents of tongue soleCynoglossus semilaevis (Günther) in the Bohai Sea     

Dou Shuozeng 《中国海洋湖沼学报》1993,11(1):89-96

Examination of the food habits and seasonal variation of the stomach contents of adult tongue sole,Cynoglossus semilaevis (Günther) taken in July 1982–July 1983 from Laizhou Bay and the Huanghe River estuary of the Bohai Sea showed crustacea, bivalvia and small fishes comprised the main prey. Invertebrates such as polychaeta, cephalopoda, gastropoda, echinodermata and actiniaria were also intermittently found in them. They intensively fed all the year found (monthly feeding rate of over 80%). The main food items wereAlpheus japonica, Alpheus distinguendus. Oratosquilla oratoria, Eucrate crenata andCarcinoplax vestitus, etc. In summer and autumn, the portion of bivalvia such asCultellus attenuatus andMusculus senhousei increased steadily. From summer to winter, a stable proportion of small fishes such asRhinogobius pflaumi andSetipinna taty was in the diet. Contribution No. 1637 from the Institute of Oceanology, Academia Sinica.  相似文献   

利用岩石化学成分判断二连盆地形成的沉积构造环境   总被引：1，自引：1，他引：1  

窦立荣  方杰 《矿物岩石》1997,17(1):50-57

二连盆地是海西期褶皱基底上发育起来的，为早白垩世断陷群。本文通过井下下白垩统巴花群４块砂岩、３块泥岩及１２块火山岩样品的镜下鉴定和化学成分测试及对比分析表明，早白垩世盆地形成的构造环境为受Ｉｚａｎａｇｉ板块向西俯冲的影响而形成的陆内裂谷，不同于渤海湾盆地早第三纪直接受太平洋板块俯冲作用而产生的主动大陆裂谷。  相似文献