The bolometric light curve of SN 1993J and the nature of its progenitor

We have constructed the bolometric light curve of SN 1993J based on UBVRI(JHK) photometric data obtained from various sources and assumingA _V = 0 and a distance modulus of 27.6. Effective temperatures and photosphere radius at various times have been obtained from detailed blackbody fits. The bolometric light curve shows two maxima. The short rise time to the second maximum, and the luminosities at the minimum and the second maximum are used to constrain the properties of the progenitor star. The total mass of the hydrogen envelope M_H, in the star is found to be ≲ 0.2 M_⊙ at the time of explosion, and the explosion ejected about 0.05 M_⊙ of Ni⁵⁶. Thin hydrogen envelope combined with a sufficient presupernova luminosity suggest that the exploding star was in a binary with a probable period range of 5yr ≤P _orb ≤ 11yr.     

软件系统开发中的组件框架技术研究、设计和应用

本文论述了组件技术的发展现状,组件框架的体系结构、组件框架的设计、开发及其选择和应用等问题。     

基于J2EE的分布式网络地理信息服务研究

从目前Web领域的发展现状出发,介绍了Web服务和J2EE架构的定义和特点,介绍了基于J2EE架构的Web应用的多层体系结构模式,并在此架构基础上对如何使用现行的Web服务技术开发Web应用进行了研究。最后给出了分布式网络地理信息服务的具体实现方法。     

手持GPS坐标系统转换参数求解方法的探讨

手持GPS使用的坐标系统是WGS-84坐标，在普通测量中，可使用5参数法转换到54北京坐标系或80国家坐标系。首先收集或采集2到3个北京坐标系x、y、B、L、h、ξ值和WGS-84坐标系B、L、H值，根据大地坐标系与空间商角坐标系的转换关系，求取相应三维直角坐标，然后利用参数转换公式求取5个转换参数Dx、Dy、Dz、DA、DF。     

基于DBBC+Mark 5B记录系统的脉冲星观测

2009年11月,云南天文台射电天文研究团组采用40 m射电望远镜以及基于DBBC(Digital Base Band Conveter)和Mark 5B的VLBI记录系统对PSR J0835-4510和PSRJ0332+5434进行了观测。观测选用S波段右旋圆极化信号,起始频率为2 206.99 MHz,总带宽为32 MHz。对数据进行相干消色散和平均后,得到PSR J0332+5434的单脉冲图像和两颗脉冲星的平均脉冲轮廓。由平均轮廓的展宽随时间的变化关系,对脉冲星的视周期作了一定修正后,得到信噪比更高的平均轮廓图。最后对轮廓的信噪比随时间的变化作了初步分析,由此可了解整个系统在观测时的稳定性。     

Java手机地图服务系统研究与实现

基于位置的服务（LBS）是指为移动设备的用户提供一系列个性化的与位置相关的服务。在分析了JSR-179规范的基础上,详细讨论了基于JSR-179规范的J2ME手机应用开发架构,并给出了J2ME手机地图服务系统的实现方法及相关程序代码。系统的实现为用户移动地、快速地提供地理信息获取支持。     

基于J2EE与ArcIMS的WebGIS构建研究与实践

设计了一个WebGIS应用系统的框架,构建了基于ArcIMS的空间信息服务体系,设计了基于非空间数据的业务逻辑计算的ＥＪＢ组件。     

IPCC emission scenarios: How did critiques affect their quality and relevance 1990–2022?

Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change’s (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique.