计算机互联网上时间传递的一种设计方案

目前,国内外时间传递方式主要有长波授时、短波地、电话授时、双星比对、ＧＰＳ时间信息等。信息产业的不断发展,使得互联网络已成为一种新的信息传递手段和资源共享方式 。通过计算机网络传输标准时间、频率将是授时领域的新课题,也是时间同步的新手段。讨论了计算机互联网上时间传递的一种设计方案,给出利用计算机网络系统实现标准时间的传递的具体方法,并介绍一种计算机互联网时间传递软件的使用方法等。     

Temporal–spatial variability of atmospheric and hydrological natural disasters during recent 500 years in Inner Mongolia,China

Natural Hazards - Inner Mongolia, located in the northern China, is a natural disaster-prone region. This study is dedicated to making a comprehensive and quantitative analysis of the...     

海洋声信道R-ω平面"纹理"特征与形成机理

采用数值模拟给出水平均匀波导环境下的声场强度在R-ω平面上的"纹理"图案,根据相位及任2号简正波之间的水平相干距离[1]随频率的变化,分析了平面中存在的"分裂"和"孤立的干涉线"2种干涉"纹理"的形成机理.     

降水统计预报模型的模拟性能分析北大核心CSCD

降水预报模型的性能与诸多因素有关,除了与研究区域特征和研究数据有关,还受到模型自身算法、统计模拟方法、性能度量指标等的影响。本文基于2015~2019年我国黑龙江省28个站点逐日降水、平均气温和平均相对湿度等地面常规气象资料,运用留出法、自助法等蒙特卡洛统计模拟和机器学习方法,首次系统研究了黑龙江省夏季逐日降水预报模型的性能和模型性能的空间分布特征。结果表明,对研究区域整体来说,BP(Back Propagation)神经网络和支持向量机的总体预报性能没有显著差异,ROC(Receiver Operating Characteristic)曲线面积值均高于76%,显著优于决策树。自助法估计的模型预报性能始终优于留出法,并且有助于提高评估结果的保真性。对研究区域单个站点来说,除个别站点以外,支持向量机的准确率和ROC曲线面积值均高于80%,并且呈现东南大西北小的空间分布趋势,该趋势与降水频率的分布基本一致。支持向量机在小兴安岭和张广才岭的总体预报效果较好,三江平原次之,松嫩平原较差;而敏感度在山区大,平原区小,中部和南部大,东部次之,西部和北部小;特异度空间分布则恰好与敏感度相反。     

Identification method of weak seismic phases on the basis of wavelet packet transform

This paper describes a sort of new method identifying seismic phase by the name of wavelet packet transform. Perfectness and development of the wavelet packet transform is based upon the idea of its multiscale analysis. The method of wavelet packet transform can depict the anomalous changes information of transient spectra of seismic wave onset, and come true the target of identifying seismic phase especially weak seismic phase. Then this paper presents discriminating examples of simulating digital signals and actual seismic phase. Compared with conventional seismic phase discrimination, studied results show that the wavelet packet transform method is an available tool of weak signal analyses, and have unexampled merits and attractive application foreground. This research gets hold of Higher School Doctor Scientific Research Foundation (No. 157 WJ0704 9435611) and supported by the National Natural Science Foundation (No. 49474211).     

Carbonaceous matter in sulfide-quartz veins at the Kurultyken base-metal deposit,eastern Transbaikal region,Russia

The carbonaceous matter filling cavities in sulfide-quartz veins at the Kurultyken hydrothermal base-metal deposit in the Khapcheranga ore district, Transbaikal region, was studied using chromatography/mass spectrometry, X-ray diffraction, thermal and isotopic analyses, and IR spectroscopy. It was established that carbonaceous matter was a maltha composed of polycyclic aromatic hydrocarbons (PAHs). Chrysene, pyrene, and benzpyrelene identified among PAHs are evidence for the hydrothermal origin of the initial carbonaceous matter of maltha. The main mass of carbonaceous matter was synthesized under reductive conditions and at a low temperature, i.e., at the final stage of base-metal ore formation. Nevertheless, the thermometric data indicate that part of the carbonic compounds could have formed at 480°C, i.e., at the high-temperature stage of the postmagmatic process. The contribution of host rocks as a source of carbonaceous matter was minimal.     

基于色层图与纹理融合的地形晕渲

针对三维地形晕渲的具体需求和存在问题,提出了一种基于色层图与纹理融合的晕渲方法。根据自定义或色层表主色调插值生成色彩连续的色层图,对地形高程进行着色;在地表材质分块的基础上,通过计算相邻材质边界上的多重纹理坐标,使用多重纹理映射进行融合过渡;最后给出了实验结果。     

地图印前计算机辅助设计软件系统研究与实践

介绍地图印前系统在我国产业部门应用概况及计算机图形辅助设计软件用于地图印前系统的三个共性问题。以计算机图形辅助设计软件MicroStation95为例,详细探讨该软件用于地图印前制作所涉及的技术要点。并以《南京市教育地图》为例,对用该软件进行彩色地图编制与出版的优点与局限性进行了探讨。     

Immobilization of phosphorus,copper, zinc and arsenic in swine manure by activated red mud

Red mud (RM), the solid waste of alumina industry, is high in silicon, calcium, aluminum and iron oxides. In this study, RM was activated by heat treatment at different temperatures and characterized with BET nitrogen gas sorption, scanning electron microscopy analysis and X-ray diffraction analysis. Immobilization of phosphorus, copper, zinc, and arsenic in swine manure by activated RM was studied as a function of RM dosage, pH and time. The immobilization efficiency of phosphorus, copper, zinc and arsenic increased with the increase in RM dosage, reaching 77, 39, 42, and 78 % when the proportion of RM to swine manure was 20 %. The pH of the solution had a significant impact on the immobilization and it was found that the efficiency increased with the increase in pH. During the 24-h immobilization, the efficiency increased with time and achieved equilibrium after 12 h. Chemical variations of phosphorus, copper, zinc, and arsenic during the immobilization process were investigated with sequential chemical extraction method and the results showed that the contents of non-labile fractions of phosphorus, heavy metals and arsenic increased obviously, whereas the contents of labile fractions decreased.     

环境干扰事件引起的“形变异常变化”

通过对山东泰安台形变观测受抽水、灌溉影响及烟台台形变观测受载荷影响的分析,认为同一台站的多套形变固体潮仪器"同步异常"的出现应成为判定异常发生的重要准则;对同一应变过程不同形变仪器的响应量级会有所不同,分量式应变仪对异常反映最有效,其次是伸缩仪。对几次"干扰异常"所揭示的问题进行了初步讨论,并在形变异常判定科学思路方面提出了一些建议。