地面电场资料在雷电预警技术中的应用

论述利用地面电场仪的探测资料对雷电预警预报的技术方法，以大气电场测量为基础，利用地面电场仪的组网，实现自动、连续、实时监测雷雨云中强雷电活动中心在地面产生的电场强度、极性以及闪电数等，提供监测范围内雷暴强电荷活动中心的发生发展演变特征和整个雷暴过程中雷电活动位置和发展信息。同时结合闪电定位系统的观测，为雷电的监测和预报提供更充分的信息。     

哈密白干湖花岗岩SHRIMP U-Pb定年及地质意义

白干湖花岗岩位于新疆哈密市白干湖南部,主体由肉红色碱长花岗岩、二长花岗岩构成。侵入岩南部与早石炭世雅满苏组接触带形成矽卡岩型铅锌矿床——白干湖西铅锌矿。为了解侵入体形成时代及确定铅锌矿成矿时代,在该岩体碱长花岗岩中采集同位素年龄样,采用SHRIMP法锆石U-Pb测年,获得岩体结晶年龄(240.4±5.6)Ma,推断白干湖西铅锌矿形成时代为印支期,即早三叠世晚期—中三叠世早期。新疆哈密白干湖花岗岩同位素测年为研究该区岩浆演化提供了年代学数据,也为本区铅锌矿成矿时代提供了年代学制约。     

Object tracking in surveillance video based on Siamese network considering geographical spatiotemporal constraints

Identifying and tracking objects in surveillance videos is an important means of mining information during surveillance. Currently, most object-tracking methods rely only on image features, which cannot accurately express the motion of the tracked object in real geographical scenes and are easily influenced by occlusion and surrounding objects having similar features. However, tracked objects, such as pedestrians and vehicles, usually move in geographical space with fixed patterns of motion, and the motion in a short time is constrained by geographical space and time, the motion trajectory is predictable, and the range of motion is limited. Therefore, based on the SiamFC object tracking framework, this study introduces geographical spatiotemporal constraints into the tracking framework and proposes the GeoSiamFC method. The objective of this is to: (1) construct the mapping relationship between geographical space and image space to solve the problem that the pixel movement within the image after perspective imaging cannot accurately express the motion of the tracked object in a real geographical scene; (2) add candidate search areas according to the predicted trajectory location to correct the tracking errors caused by the occlusion of the object; and (3) focus on the search for the range of motion of the mapped pixel within the image space according to the limited geographical range of motion of the tracked objects in a certain time to reduce the interference of similar objects within the search area. In this study, separate experiments were conducted on a common test dataset using multiple methods to deal with challenges such as occlusion and illumination changes. In addition, a robust test dataset with noise addition and luminance adjustment based on the common test dataset was used. The results show that GeoSiamFC outperforms other object-tracking methods in the common test dataset with a precision score of 0.995 and a success score of 0.756 compared with most other object-tracking algorithms under the base condition of using only shallow networks. Moreover, GeoSiamFC maintained the highest precision score (0.970) and high success score (0.734) in the more challenging robust test dataset as well. The tracking speed of 59 frames per second far exceeds the real-time requirement of 25 FPS. Geographical spatiotemporal constraints were considered to improve tracker performance while providing real-time feedback on the motion trajectory of the target in geographical space. Thus, the proposed method is suitable for real-time tracking of the motion trajectory of a target in real geographical scenes in various surveillance videos.     

白令海深海异常沉积特征及成因分析

利用中国历次北极科学考察航次在白令海北部陆坡及海盆等深水区所采集的沉积物样品,对其开展沉积学等研究,系统归纳该海域常见的异常沉积类型及特征,并初步探讨其可能成因。BR02孔出现至少3段浊积层,浊积层主要分布于末次冰消期至中全新世。B5-4孔存在至少2段火山碎屑沉积层,其沉积年代分别约为1.3 ka BP和13.2 ka BP。B5-7站表层沉积物中的硅藻组合以新近系硅藻化石Kisseleviella carina Sheshukova-Poretzkaya和Kisseleviella ezoensis Akib为主,且与附近海域其他表层沉积物的硅藻组合面貌差异明显,可能是沉积物再沉积结果,其初始沉积年代大约为早中新世。白令海北部陆缘/陆坡区附近遍布的海底大峡谷对该区沉积物沉积过程具有重要影响,可能是导致该区浊流沉积与再沉积物的主要原因。此外,白令海位于欧亚板块、太平洋板块及北美板块交汇区边缘,其独特的地理位置决定该区地震与火山等构造活动相对活跃,进而进一步促使该区海底异常沉积现象频发。     

磨刀门河口在20世纪60至70年代的演变模拟与动力地貌过程分析

使用长周期动力地貌模型(long-term morphodynamic model),再现了磨刀门河口1964—1977年的演变过程,并从水动力、地形演变规律以及人类活动等角度系统分析了长周期地貌演变过程。模拟结果显示在1964—1977年磨刀门河口鹤州至交杯沙浅滩和上沟快速淤积,13a的平均淤积厚度均在40cm以上,与之相反,横洲水道杧州至大井角段和上沟东部深槽冲刷明显。磨刀门河口演变季节性特征明显。在洪季浅滩淤积,深槽冲刷;在枯季滩槽都处于淤积状态。演变过程中各种基岩岛屿使动力结构和演变规律呈现多元化,同时人类活动对整个区域的演变起到了重要的作用。     

Effect of sodium chloride and cadmium on the growth,oxidative stress and antioxidant enzyme activities of Zygosaccharomyces rouxii

Zygosaccharomyces rouxii is a salt-tolerant yeast species capable of removing cadmium(Cd) pollutant from aqueous solution. Presently, the physiological characteristics of Z. rouxii under the stress of sodium chloride(NaCl) and Cd are poorly understood. This study investigated the effects of NaCl and Cd on the growth, oxidative stress and antioxidant enzyme activities of Z. rouxii after stress treatment for 24 h. Results showed that NaCl or Cd alone negatively affected the growth of Z. rouxii, but the growth-inhibiting effect of Cd on Z. rouxii was reduced in the presence of NaCl. Flow cytometry assay showed that under Cd stress, NaCl significantly reduced the production of reactive oxygen species(ROS) and cell death of Z. rouxii compared with those in the absence of NaCl. The activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) of Z. rouxii were significantly enhanced by 2%–6% NaCl, which likely contributed to the high salt tolerance of Z. rouxii. The POD activity was inhibited by 20 mg L-1Cd while the SOD and CAT activities were enhanced by 8 mg L-1 Cd and inhibited by 20 mg L-1 or 50 mg L-1 Cd. The inhibitory effect of high-level Cd on the antioxidant enzyme activities of Z. rouxii was counteracted by the combined use of NaCl, especially at 6%. This probably accounted for the decrease in Cd-induced ROS production and cell death of Z. rouxii after incubation with NaCl and Cd. Our work provided physiological clues as to the use of Z. rouxii as a biosorbent for Cd removal from seawater and liquid highly salty food.     

井地大地电磁非线性共轭梯度二维反演研究

本文提出并验证了地下大地电磁测深数据的正、反演算法和程序,为井地大地电磁测深和井地可控源音频大地电磁测深这一前沿研究课题提供了地球物理解释方法.使其更加完善和有效.在Rodi(2001)发表的大地电磁场二维NLCG反演理论和算法的基础上,推导了井地大地电磁场二维NLCG反演算法,改编反演的代码,开发出二维NLCG反演程...     

复杂金属矿体地震波正演模拟研究-以庐枞罗河-泥河-大包庄矿床为例

地震勘探在金属矿勘查中发挥越来越重要的作用,但复杂的介质结构和矿体形态通常使金属矿地震解释异常困难,为深入研究复杂金属矿体的地震波场特征,有效开展金属矿地震解释,本文以庐枞矿集区的罗河、泥河和大包庄矿床为例,在详细开展物性测量和地质与地球物理建模的基础上,对均匀介质复杂矿体模型、简化矿体模型和随机介质简化矿体模型进行了...     

Equations for the near‐surface mass flux density profile of wind‐blown sediments

The erosion of sediment by wind and the resulting mass flux density profile is thought to be described by a mathematical function that bears information on the mechanisms responsible for the movement of individual particles by the wind, and such functions have been studied extensively. In this study several functions are evaluated that have been proposed to describe the variation in mass flux density with height of wind‐blown sediment, with the flux containing a mixture of particles in suspension and saltation, based on detailed field data at four land types in the Minqin area of north‐western China, where severe wind erosion occurs. High‐resolution mass flux density measurements at 50 heights, collected at 20 mm intervals to a height of 1 m above the surface, were obtained using vertically segmented samplers. Three kinds of functions fit the measured flux density profiles reasonably well, but a three‐parameter modified exponential function is preferred because it contains fewer coefficients to be defined and provides a reasonably good fit to the measured mass flux density profiles. This and previous conclusions suggest that the decay with height of mass flux density of sediments dominated by saltation particles as in the present study tends to follow a modified exponential function law, but a modified power function law replaces the modified exponential function law when the height extends to a level high enough to be dominated by suspension particles. Copyright © 2011 John Wiley & Sons, Ltd.