北京主城区伪基站活动时空特征及其影响因素     

李旭亮  陶海燕  卓莉  李秋萍  汪珂丽 《热带地理》2019,39(1):125-134

利用北京主城区2017-02-23—04-26的垃圾短信数据反映伪基站的活动轨迹,通过核密度估计分析伪基站的时空特征;以1 km格网为研究单元,采用空间计量模型定量分析了建成环境与社会经济因素对伪基站分布的影响。结果发现：1）伪基站活动呈现出明显的时空集聚,空间上东多西少,最大的热点区域位于国贸。2）伪基站活动存在显著的空间自相关性,邻近区域伪基站发送垃圾短信增加1%,相应本区域增加约0.7%。3）建成环境因素中,正向影响最大的是商业和住宅,负向影响最明显的是酒店设施,教育设施存在显著的负空间溢出效应;交通方面,地铁站对伪基站活动的吸引作用仅存在于邻近区域。4）社会经济因素中体现了伪基站活动与低收入群体、人流活动和老龄人口均存在一定正相关性。  相似文献   

Simulating the spatial diffusion of memes on social media networks     

Lanxue Dang  Zhuo Chen  Ming-Hsiang Tsou 《International journal of geographical information science》2019,33(8):1545-1568

This article reports the findings from simulating the spatial diffusion processes of memes over social media networks by using the approach of agent-based modeling. Different from other studies, this article examines how space and distance affect the diffusion of memes. Simulations were carried out to emulate and to allow assessment of the different levels of efficiency that memes spread spatially and temporally. Analyzed network structures include random networks and preferential attachment networks. Simulated spatial processes for meme diffusion include independent cascade models and linear threshold models. Both simulated and real-world social networks were used in the analysis. Findings indicate that the numbers of information sources and opinion leaders affect the processes of meme diffusion. In addition, geography is still important in the processes of spatial diffusion of memes over social media networks.  相似文献   

蠲痹历节清方对急性痛风性关节炎动物模型消肿抗炎疗效的实验研究          下载免费PDF全文

向黎黎  杨卓  熊辉 《应用海洋学学报》2019,35(11):133-135

目的：探讨蠲痹历节清方对急性痛风性关节炎动物模型肿胀与炎症的影响,探讨其可能的作用机制。方法：将48只SPF级健康雄性湘黄鸡随机分为正常组、模型组、蠲痹历节清方组、别嘌醇组,每组12只。采用高蛋白饮食的方法（饮食中的蛋白含量为50%）建立鸡痛风性关节炎模型。正常组及模型组予0.9%氯化钠注射液灌胃,蠲痹历节清方组予蠲痹历节清方汤剂（30ml/kg）灌胃,别嘌醇组予别嘌醇溶液（15ml/kg）灌胃,每天2次,共21d。观察干预后不同时间点各组动物踝关节肿胀程度及炎症细胞数量。结果：1）踝关节肿胀指数。干预1d,与正常组相比,模型组、蠲痹历节清方组及别嘌醇组踝关节肿胀指数均上升,差异有统计学意义（P<0.05）;干预7、14、21d,与模型组相比,蠲痹历节清方组及别嘌醇组踝关节肿胀指数均下降,差异均有统计学意义（P<0.05）;干预21d,蠲痹历节清方组与别嘌醇组差异无统计学意义（P>0.05）。2）炎症细胞数量。干预21d,与正常组相比,模型组白细胞、淋巴细胞、中性粒细胞数量均升高,差异有统计学意义（P<0.05）;与模型组相比,蠲痹历节清方组及别嘌醇组白细胞、淋巴细胞、中性粒细胞数量均下降,差异有统计学意义（P<0.05）。结论：蠲痹历节清方对鸡急性痛风性关节炎模型有明显的消肿抗炎作用,且有助于缓解关节疼痛。  相似文献   

Taxonomy,Morphology and Phylogeny of a New Oligotrich Ciliate-Omegastrombidium hongkongense n. sp.(Protozoa: Ciliophora) from Clear Water Bay,Hong Kong     

SHEN Zhuo  LIU Weiwei  ZHANG Shuwen  YI Zhenzhen  LIU Hongbin 《中国海洋大学学报(英文版)》2018,(4)

One new marine oligotrich ciliate, Omegastrombidium hongkongense n. sp., was isolated from a bloom of Noctiluca scuntillans near Port Shelter, Hong Kong. The morphology and infraciliature of this new species were studied on both living and protargol-stained specimens. Its phylogenetic position was discussed based on the sequence of the small subunit r RNA gene. O. hongkongense is different from its congeners with special characters. The cells are usually heart-shaped, and the cell size usually is(20–35) ×(20–30) μm in vivo. Its deep buccal cavity extends obliquely to about 1/2 of cell length. It shows prominent apical protrusion. The adoral zone of membranelles is divided into 17–19 collar membranelles and four buccal membranelles. It has one ball-like macronucleus. The girdle kinety forms a closed loop which obliquely surrounds the body. The ventral kinety and thigmotactic membranelles are not observed. The SSU r RNA sequence of O. hongkongense was close to those of Strombidium paracalkinsi and Varistrombidium kelum with approximately 99% similarity. In the phylogenetic trees, O. hongkongense can be grouped with O. elegans and V. kielum species with very low support(16% ML).  相似文献   

热液喷口探测化学传感器的研制及应用*     

秦华伟  陶卓  李怀明  岳羲和  蔡真  陈升  周红伟  叶瑛 《热带海洋学报》2018,37(3):86-92

海底热液喷口周围的水体具有显著的浊度和化学组分异常, 是寻找热液喷口的重要标志。文章提出了一种海底热液喷口的探测技术方法, 设计了低功耗化学传感器。该化学传感器可搭载在相关平台, 实时探测水体的Eh、H₂S、pH及CO₃^2-等电位值, 结合浊度异常, 可以推断热液喷口的位置。在西南印度洋中脊海试结果表明, 该化学传感器可有效探测由热液活动产生的水体异常, 是一种探测海底热液喷口的有效技术。  相似文献   

一种改善GPS接收机载波相位连续性的相位预测方法     

李卓  张提升  严昆仑  祁发瑞 《大地测量与地球动力学》2018,38(12):1280-1284

针对GPS信号受短时遮挡等影响导致载波相位不连续问题,提出一种基于载波开环跟踪的相位预测方法。通过对失锁通道的多普勒进行精确预测实现对载波相位进行开环跟踪,重点改善接收机晶振钟漂对多普勒估计精度的影响。基于软件接收机对该方法进行性能评估,在部分GPS信号连续中断15 s情况下,其估计的载波相位误差小于1/4周的概率在90%以上。  相似文献   

PT型袖珍贯入仪在海岸带地区工程地质调查中的应用          下载免费PDF全文

徐华  徐建国  张卓  张涛  纪汶龙 《山东国土资源》2018,34(4)

通过对莱州湾地区工程地质勘察中大量袖珍贯入试验与静力触探试验、标准贯入试验、土工试验数据的对比分析,采用数理统计方法,建立了PT型袖珍贯入阻力与静力触探试验指标、标准贯入试验击数、土的液性指数及压缩模量相关公式。为今后在海岸带地区工程地质勘察中,采用PT型袖珍贯入仪对岩心的现场贯入试验,及时准确地判定土的物理力学性质提供了依据。  相似文献   

Impact of small-scale structures on estuarine circulation     

Zhuo Liu  Yinglong J. Zhang  Harry V. Wang  Hai Huang  Zhengui Wang  Fei Ye  Mac Sisson 《Ocean Dynamics》2018,68(4-5):509-533

We present a novel and challenging application of a 3D estuary-shelf model to the study of the collective impact of many small-scale structures (bridge pilings of 1 m × 2 m in size) on larger-scale circulation in a tributary (James River) of Chesapeake Bay. We first demonstrate that the model is capable of effectively transitioning grid resolution from ~?400 m down to ~?1 m near the pilings without introducing undue numerical artifact. We then show that despite their small sizes and collectively small area as compared to the total channel cross-sectional area, the pilings exert a noticeable impact on the large-scale circulation, and also create a rich structure of vortices and wakes around the pilings. As a result, the water quality and local sedimentation patterns near the bridge piling area are likely to be affected as well. However, when evaluating over the entire waterbody of the project area, the near field effects are weighed with the areal percentage which is small compared to that for the larger unaffected area, and therefore the impact on the lower James River as a whole becomes relatively insignificant. The study highlights the importance of the use of high resolution in assessing the near-field impact of structures.  相似文献   

虚拟化平台与存储系统结合在地震台网中的部署和应用     

王卓  张美玲  康健  方瑶  贾军  郝永梅 《防灾减灾学报》2018,(2):73-77

介绍了黑龙江省地震台网虚拟化平台与存储系统的特点和部署应用方式,将虚拟化平台与存储系统相结合,实现服务器资源灵活分配的同时,强化数据的安全性,为地震台网的各项业务提供安全灵活的底层基础平台。  相似文献   

基于集合卡尔曼滤波的湖泊富营养化模型Delft3D-BLOOM数据同化     

刘卓  李志杰  胡柳明  林育青  陈求稳 《湖泊科学》2017,29(5):1070-1083

富营养化模型是进行湖泊水环境质量预测和管理的重要工具,然而模型客观存在的误差一直是应用者关心的重要问题.数据同化作为连接观测数据与数值模型的重要方法,可以有效提高模型的准确性.集合卡尔曼滤波(En KF)是众多数据同化算法中应用最为广泛的一种,可进行非线性系统的数据同化,并能有效降低数据同化的计算量.本研究以太湖作为具体实例,选择Delft3D-BLOOM作为富营养化模型,在数值实验确定En KF集合数为100、观测误差方差为1%、模拟误差方差为10%的基础上分别进行模型状态变量同化以及状态变量与关键参数同步同化.结果显示,仅同化状态变量时,模型预测精度有所增加;同时同化状态变量和关键参数时,可显著提升模型在湖泊水环境质量预测中的精度.该研究为应用集合卡尔曼滤波以提高复杂的湖库富营养化模型模拟精度提供了有效的方法.  相似文献