Wind variability in intermediate luminosity B supergiants

We discuss wind variability in intermediate luminosity B supergiants. Because these are not the hottest, most luminous or just about other kind of -est stars, they have not attracted much attention. However, since their wind lines are well-developed, but unsaturated, they make ideal diagnostics for time dependent wind studies. We show that their wind profiles undergo large scale variability and that this phenomenon is quite common. We also discuss a time series for the B0.5 Ib HD 64760 which suggests the long sought after connection between wind and photospheric activity. Newly developed analysis techniques needed to extract physical information from the wind lines are discussed, and results are applied to the time series.     

科学大洋钻探中的新技术

大洋钻探诸多科学目标的实现与包括钻探、取芯、测试和海底观测技术在内的各种新技术的开发和革新密不可分。即将开展的IODP计划,将对各种技术提出新的要求。在钻探技术上,将联合使用多平台,以实现区域更广深度更大的钻探作业;在取芯技术上,取样范围更广,从各种岩石取样到地下流体的取样,并要求样品保持原始状态,同时确保获得更高的岩芯采收率;在测试上,要求采用随钻测试技术,以适时地获得地下真实信息;在观测技术上,要求开发各种工具,去除由于钻探造成的扰动,使得各种观测仪器能够进行长期的跟踪观测。     

信息安全实验管理系统的实现及其系统中安全问题的解决

B／S模式的应用系统都要面对安全的问题，身份认证和访问控制是实现计算机安全的主要手段。介绍了基于Web的信息安全实验管理系统，分析了系统的体系架构和功能，针对B／S模式的安全威胁，采用了两个方案实现身份认证和访问控制。     

90年代中国省级区域经济与环境协调度分析

在阐述经济环境协调度理论的基础上,建立了环境承载力与经济发展水平之间的协调度模型。并通过对90年代我国省级区域的实证分析,发现我国空间区域经济环境协调度基本符合“U”型曲线,区域经济发展模式大多以牺牲环境为代价,特别是中西部地区的问题比较严重。     

基于HJ-1A/1B的2014年黄海海域浒苔灾害时空分布

自2007年以来, 黄海海域每年的5月初～8月中下旬浒苔(Ulva prolifera)会周期性地暴发与消亡,导致海洋生态环境被破坏以及经济损失。利用2014 年的HJ-1A/1B遥感影像, 利用神经网络监督分类及RULE规则影像重分类动态阈值法, 对2014年的浒苔的漂移路径、各时期影响的海域面积、分布面积以及暴发高峰期的最大面积进行了动态监测。结果表明, 2014年浒苔持续时间为101 d, 5月中旬开始在江苏省盐城市近海出现零星斑点, 分布面积为2.299 km², 影响面积为1 744.799 km²; 6月初到6月中旬浒苔广泛分布于黄海海域, 分布面积扩大至1 367.145 km², 达到当年的峰值; 从6月下旬开始, 浒苔进入衰退期, 浒苔分布面积、相对聚集密度均急剧缩小, 但影响面积的峰值出现在该时期; 8月初消亡于青岛附近海岸, 8月20日遥感影像已难以监测到浒苔的存在。2014年黄海海域浒苔经过了“出现—发展—暴发—衰退—消亡”5个发展阶段。     

建立WebGIS的月球三维可视化关键技术

嫦娥工程获得了大量月球探测数据。针对让公众用户通过网络获取月球信息,更好了解月球知识的需求,地面应用系统提出了建立基于WebGIS的月球三维可视化系统的解决方案。首先介绍了国内外三维月球的发展现状,详细分析了开发WebGIS系统的客户端和服务器端技术,重点阐述了月球空间数据模型和三维场景可视化渲染等三维GIS可视化关键技术,为建立我国的三维月球可视化系统提供了理论支持。     

HY-2B扫描微波辐射计海温产品在典型区域的精度验证和分析

“海洋二号B”卫星（HY-2B）于2018年10月25日发射,是我国第二颗海洋动力环境探测卫星,其上搭载有包括扫描微波辐射计（SMR）在内的多个载荷,海表面温度（SST）是SMR的主要产品之一。本文分别利用NOAA提供的iQuam实测海温数据、CORIOLIS卫星WINDSAT反演的海温遥感产品、NCEP模式海温数据,在两个典型区域,对2020年1月1日至2020年12月31日期间的HY-2B/SMR海温产品进行了验证,其中HY-2B/SMR与iQuam实测海温的Bias为0.004℃,RMSE为0.65℃左右,CORR高于0.95。通过进一步分析,由区域A的分析结果揭示出HY-2B/SMR海温产品精度随纬度变化的规律及其原因,同时,由区域B的分析结果揭示出陆地、岛礁以及RFI对海温总体反演精度的影响约为0.1℃。     

利用遥感技术建立墨西哥热带地上生物量模型(英文)

Spatially-explicit estimation of aboveground biomass(AGB) plays an important role to generate action policies focused in climate change mitigation,since carbon(C) retained in the biomass is vital for regulating Earth’s temperature.This work estimates AGB using both chlorophyll(red,near infrared) and moisture(middle infrared) based normalized vegetation indices constructed with MCD43A4 MODerate-resolution Imaging Spectroradiometer(MODIS) and MOD44B vegetation continuous fields(VCF) data.The study area is located in San Luis Potosí,Mexico,a region that comprises a part of the upper limit of the intertropical zone.AGB estimations were made using both individual tree data from the National Forest Inventory of Mexico and allometric equations reported in scientific literature.Linear and nonlinear(expo-nential) models were fitted to find their predictive potential when using satellite spectral data as explanatory variables.Highly-significant correlations(p = 0.01) were found between all the explaining variables tested.NDVI62,linked to chlorophyll content and moisture stress,showed the highest correlation.The best model(nonlinear) showed an index of fit(Pseudo-r2) equal to 0.77 and a root mean square error equal to 26.00 Mg/ha using NDVI62 and VCF as explanatory variables.Validation correlation coefficients were similar for both models:lin-ear(r = 0.87**) and nonlinear(r = 0.86**).     

A timing formula for main-sequence star binary pulsars

In binary radio pulsars with a main-sequence star companion, the spin-induced quadrupole moment of the companion gives rise to a precession of the binary orbit. As a first approximation one can model the secular evolution caused by this classical spin-orbit coupling by linear-in-time changes of the longitude of periastron and the projected semi-major axis of the pulsar orbit. This simple representation of the precession of the orbit neglects two important aspects of the orbital dynamics of a binary pulsar with an oblate companion. First, the quasiperiodic effects along the orbit, owing to the anisotropic 1/ r ³ nature of the quadrupole potential. Secondly, the long-term secular evolution of the binary orbit, which leads to an evolution of the longitude of periastron and the projected semi-major axis, which is non-linear in time.   In this paper a simple timing formula for binary radio pulsars with a main-sequence star companion is presented which models the short-term secular and most of the short-term periodic effects caused by the classical spin-orbit coupling. I also give extensions of the timing formula that account for long-term secular changes in the binary pulsar motion. It is shown that the short-term periodic effects are important for the timing observations of the binary pulsar PSR B1259–63. The long-term secular effects are likely to become important in the next few years of timing observations of the binary pulsar PSR J0045–7319. They could help to restrict or even determine the moments of inertia of the companion star and thus probe its internal structure.   Finally, I reinvestigate the spin-orbit precession of the binary pulsar PSR J0045–7319 since the analysis given in the literature is based on an incorrect expression for the precession of the longitude of periastron. A lower limit of 20° for the inclination of the B star with respect to the orbital plane is derived.