Wavelet analysis and the detection of non-Gaussianity in the cosmic microwave background

We investigate the use of wavelet transforms in detecting and characterizing non-Gaussian structure in maps of the cosmic microwave background (CMB). We apply the method to simulated maps of the KaiserStebbins effect resulting from cosmic strings, on to which Gaussian signals of varying amplitudes are superposed. We find that the method significantly outperforms standard techniques based on measuring the moments of the pixel temperature distribution. We also compare the results with those obtained using techniques based on Minkowski functionals, and we again find the wavelet method to be superior. In particular, using the wavelet technique, we find that it is possible to detect non-Gaussianity even in the presence of a superposed Gaussian signal with 3 times the rms amplitude of the original cosmic string map. We also find that the wavelet technique is useful in characterizing the angular scales at which the non-Gaussian signal occurs.     

广西6、7月份若干日内最大日降水量的概率分布

对广西16站用6、7月逐日降水量资料估计了日降水量的条件概率密度函数,并递推得1～20天内最大日降水量的概率分布.主要结果是:分布能较准确地逼近前一日有雨和无雨两种条件下日降水量的样本频率分布;大多数站在10日内最大日降水量在20～30毫米的概率最大,约0.2,20日内最大日降水量在30～50毫米的概率最大;北海和钦州10、20日内最大日降水量达100毫米以上的概率明显大于其它站.     

美国矿床环境研究动态及建议

通过收集美国地质调查局近几年公开出版物及其网站上发布的资料,总结了美国在环境矿床学研究方面的最新成果,内容涉及32种矿床的地质—环境模型、矿床的环境地球化学背景或基准值、流域性矿床—环境综合研究和特殊矿床的环境效应等方面。结合美国的研究成果和我国国情,建议我国地质调查局现阶段在该领域研究首先集中在矿床的地质—环境模型和用于战略性资源评价中的矿床环境评价指标等战略性研究上。     

利用主成分背景抑制的红外目标检测

提出了一种基于主成分背景抑制的红外目标检测算法。首先分析了红外成像的时空相关性,采用主成分分析技术分解时域关联信息抑制背景杂波;接着采用空间关联模糊自适应共振神经网络建立时空背景模型检测目标。实验结果显示,该算法能有效地抑制背景突显目标和检测出复杂场景下的红外目标,其F1指标值高达94.2%。     

祁连成矿带成矿规律和找矿方向

在系统分析区内成矿条件和区域成矿特征的基础上,提出海相火山岩型、接触交代型(矽卡岩型)、变质(包括沉积-变质)型、沉积型(含喷气-沉积型)、构造蚀变岩型等是该区的主攻矿床类型。通过对祁连成矿带地质、矿产、物探、化探、遥感等资料的综合分析,并结合野外调研和室内的再研究,共圈定69处成矿远景区,其中A类5处,B类23处、C类41处。在此基础上,结合最新的地质找矿成果,优选出铜、金、铅、锌、钨远景区16处,作为今后矿产资源评价首选地区。     

湘南西部内生金属成矿系列及找矿方向

湘南西部处于南岭多金属成矿带中段,矿产资源丰富.在新一轮国土资源大调查中,认为内生金属矿的形成受一定的沉积建造、地质构造和岩浆岩控制,呈规律性分布.根据成矿地质背景和矿床组合特征,可划分3个成矿系列,即与1型花岗岩类有关的铜铅锌银成矿系列,与S型花岗岩类有关的钨锡铅锌铜银成矿系列和沉积改造型铁锰铅锌成矿系列.最后,以区内地质成矿规律、地球物理、地球化学及已知矿产分布等为依据,建立找矿标志,提出找矿靶区,指出每个靶区的主攻矿种和主攻矿床类型.     

SURFACE OZONE CHARACTERISTICS AT THREE STATIONS IN GAW OF WMO IN CHINA*

The characteristics of surface O₃ on clear days at Waliguan Observatory,Lin'an regional station and Longfengshan regional station in China were analyzed in this paper.The three stations belong to Global Atmospheric Watch(GAW)of WMO.There was obvious daily variation on clear days at Lin'an.with maximum(42.9 ppb)and minimum(20.3 ppb)of daily range appearing in spring and summer,respectively.The daily variation was more regular at Lonfengshan than at Lin'an.The maximum(about 27 ppb)appeared in autumn at Longfengshan.There was no obvious daily variation and also daily range was smaller in other seasons except weaker daily variation in summer at Waliguan.But the surface O₃ concentration(SOC)in summer was higher than that in winter at Waliguan.The SOC on clear days of summer at Waliguan was over 20 ppb higher than at Longfengshan and Lin'an.The global radiation and NO_x concentration were the main factors which control the SOC on clear days at Longfengshan and Lin'an.and played important role in different seasons and areas.The transportation of air flow around the area of Qinghai-Xizang(Tibet)Plateau was the main cause for high SOC and weak daily variation in summer at Waliguan.The similar effect of transportation was obtained at the Mauna Loa Observatory.The distribution characteristics of SOC increasing with height in the troposphere determined the difference of SOC between East China and West China.     

索赔计数相依风险模型

考虑了一类索赔计数相依的风险模型,该模型假设每次主索赔可随机产生一副索赔,得到了该风险模型生存概率所满足的微积分方程,并在索赔额为指数分布的情形下,给出了生存概率的精确表达式.     

基于概率分布法的典型内陆河流域径流未来变化

基于黑河干流历史时期（1960 - 2012年）和RCPs（本文RCPs指RCP2.6、 RCP4.5和RCP8.5三种情景）情景下预估的未来（2013 - 2100年）月平均流量和冰川融水数据, 运用概率分布法和河道来水量距平法, 分析了黑河干流出山径流量与冰川融水径流量及其极值的未来变化趋势与程度、 径流丰枯变化以及冰川融水径流对黑河出山径流的补给与调节作用的变化。结果表明, 相较历史时期, 不同RCPs情景下未来黑河干流出山径流量将略呈增加态势, 但不显著; 月最大（7 - 8月）出山径流量将大幅度减少, 不确定性降低, 月最小（12月 - 翌年1月）出山径流量变化不明显。未来黑河干流, 不同RCPs情景下枯水年的发生概率将增加2～3倍, 偏枯水年在RCP2.6和RCP4.5情景下的发生概率亦将增大; 黑河干流未来可能进入平水年, 甚至枯水年。未来黑河干流年冰川融水径流与月最大冰川融水径流均显著减少, 对黑河径流的补给与调节作用均降低。