用模糊数学方法刻划公众对天气预报的感受度

气象部门将6小时的降雨按降雨量划分为无雨、小雨、中雨、大雨、暴雨、大暴雨及特大暴雨七个级别进行预报,这与公众感受认可这些降雨量级别的程度是有差异的.即使气象部门预报的很准,这种差异有可能使公众感受到降雨级别的程度和预报的级别不符,从而认为预报得不准确,用模糊数学的方法对公众的感受度进行了刻划,给出了计算预报数据与公众感受度差异的数值公式及方法.     

Detection and Identification of the Herbicide Isoproturon and its Metabolites in Field Samples After a Heavy Rainfall Event

Abstract

The occurence of isoproturon [N-(4-isopropylphenyl)-N′, N′-dimethyl urea] and its metabolites was investigated in soil solution, runoff and creek water from a farm in Scheyern (Bavaria, FRG) after a heavy rainfall event following the application in spring 1994. The analytical procedure included enrichment by C 18 solid-phase extraction and reversed-phase HPLC with diode array detection. The major degradation product in most of the samples was identified as 2-hydroxy-isoproturon [N-(4-(2-hydroxyisopropyl)-phenyl)-N′. N′ dimethyl urea] using the authentic compound. The latter has been isolated from wheat cell culture medium and its structure elucidated by NMR and MS. Furthermore, the polar metabolites monodesmethyl-isoproturon [N-′ (4-Isopropylphenyl)-N′-methyl urea] and 2-hydroxy-monodesmethyl-isoproturon [N-(4-Isopropylphenyl)-N′-methyl urea] and 2-hydroxy-monodesmethyl-isoproturon [N-(4-(2-hydroxyisopropyl)-phenyl)-N′-methyl urea] were identified by comparison of their retention times and DAD-UV spectra with reference compounds.

The detection of isoproturon in soil solution down to 170 cm depth and in creek water in concentrations exceeding 4 μg/1 and also of the polar metabolites in concentrations up to 0,9 μg/1 indicated the mobility of this phenylurea herbicide and its degradation products. Therefore the metabolites should be considered in studies on the migration of isoproturon and in the ecotoxicological evaluation.     

TiCl4/MgCl2催化剂载钛量对交联烯烃聚合的影响

研究了载钛量不同的两种MgCl2/TiCl4催化剂对1,5-已二烯交联烯烃催化活性的影响.并用凝胶渗透色谱(GPC)测定了其聚合物的分子量及其分布;用旋转粘度计和超声波仪研究了其聚合物溶液的抗剪切稳定性.结果表明,载钛量较高的MgCl2/TiCl.催化剂的交联聚合活性较好.所合成聚合物的分子量较低.分子量分布较宽,且其抗剪切稳定性能也较好.     

流动注射在线共沉淀分离富集HG—AFS测定痕量锗

提出了一种流动注射在线共沉淀-氢化物发生-原子荧光光谱法测定痕量锗的分析方法。设计了在线共沉淀及氢化物发生流路和操作程序,选择了各项化学条件和流路参数。方法操作简便快速,分析速度为30/h,检出限为0.11ng,相对标准偏差（n=5)为5.6%,经国家一级地质标样分析验证,方法可靠实用。     

饮用天然矿泉水的锶限量指标

从锶对人体健康有益、锶的毒性很低、人类可能缺锶以及天然淡水锶含量考察等四个方面论述了提高我国饮用水锶限量指标的必要性,参考动物实验胚胎正常发育需要量、人类流行病学调查最佳饮水锶水平和临床安全剂量,建议将我国饮用天然矿泉水锶限量指标从5mg/L提高到10mg/L。     

脉冲裂变中子总数测量新方法的理论研究

 简述了作者提出的脉冲裂变中子测量原理，介绍了一种采用中子灵敏度补偿原理建立的中子测量探测系统，即由辐射衰减器+载⁶Li塑料闪烁探测器组成的探测系统。采用数值模拟方法对该探测系统的参数进行了优化计算，给出了理论优化计算结果并进行了分析讨论，对这种方法和探测系统的适应性进行了分析，预测了这种方法的应用前景。     

供给总量限定需求区间约束型运输问题——时限费用优化模型与算法

本文目的是为建立与运输问题有关的决策支持系统提供方便.本文建立了供给总量限定需求区间约束型运输问题的对时限与费用两个目标进行优化的多目标规划模型,给出了求解模型的算法,并举例说明了算法的应用.该算法能求得问题的最优解,并具有易于编程实现、收敛性好等优点.数值实验表明该算法有较高的计算效率,可用于求解某些类型的指派问题.     

NORTHERN HEMISPHERIC SUMMER CLIMATIC JUMP IN THE 1960s (Ⅰ)——RAINFALL AND TEMPERATURE

With the conception of the climatic jump, the authors revealed the large-scale characteristics of the abrupt summer climatic change in the Northern Hemisphere in the 1960s. This paper concerns the change of the summer rainfall, air temperature and sea surface temperature in 1951—1980. There was a wide zone including North Africa, northwest India, central China and Japan where the rainfall decreased abruptly in the 1960s while two zones, respectively south and north of the drying zone, experienced increasing rainfall. The temperature decreased abruptly in most of the northern mid-high latitudinal regions and increased significantly in some of the lower-latitudinal regions, leading to a sudden enlarging of the equator-polar thermal difference. It was noted that the climatic jump seemed to occur asynchronously from one region to another.     

低空急流的加强对深厚西南低涡发展及稳定维持的作用

1998年7月下旬长江中下游发生罕见的特大洪涝灾害，分析认为低空急流在7月20日10Z突然加强，在四川盆地东北侧引起低层强辐合是西南低涡得以发展的重要原因；低空急流加强引起的低层强辐合产生的潜热释放，导致中层位涡的增加，使得低涡十分深厚，低空急流在21－23日的另两次加强在西南低涡的南部引起的低层强辐合，弥补了低涡由于低层摩擦引起的旋转减弱，使低涡长期稳定维持。     

基于模式误差分布特征的中国夏季旱涝预测可信度研究

基于美国气候预报中心组合降雨分析资料对国家气候中心海气耦合模式多年夏季降水预报误差进行统计分析,以揭示模式预报误差的分布规律及特征.研究发现,模式预报误差分布特征满足正态分布,基于误差分布特征分析模式对中国夏季降水的预测能力,通过误差分布的高斯拟合曲线特征对比模式预报与动力统计方法的预测技巧,进而得到动力统计方法改进误差分布特征的两种类型:1)变幅型改进;2)均值型改进.在此基础上,根据模式误差的统计特征提出了一种新的旱涝预测可信度计算方法,用于定量化地评估动力统计方法在不同地区的预测可信度大小,并应用于实际预测.最后以2012和2013年夏季降水为例,给出了实况、预测以及可信度检验.结果显示该方法能较好地反映出预测的不确定性,较其他检验方法更具针对性,对异常降水的预测可信度反映更为准确,验证了方法的有效性,可进一步提高动力统计方法的预测服务水平.