基于Web的教学超媒体中的自适应导航支持技术

用户利用WWW浏览器进行学习的最大障碍是：用户必须自行应付大量的学习材料和导航链，而有时它们是与学习目标无关的，解决问题的有效方法是自适应超媒体环境的实现，即既保持WWW特有的转称分便性，又能为用户提供导航支持，基于用户的学习历史指导下一步学习内容的选择，本文介绍基于Web的教学超媒体中的ANS技术，给出了构造领域模型和用户模型的技术方法，并着重讨论了一些简单而且有效的ANS技术。     

Preliminary estimation of the organic carbon pool in China’s wetlands

Accurate estimation of wetland carbon pools is a prerequisite for wetland resource conservation and implementation of carbon sink enhancement plans.The inventory approach is a realistic method for estimating the organic carbon pool in China’s wetlands at the national scale.An updated data and inventory approach were used to estimate the amount of organic carbon stored in China’s wetlands.Primary results are as follows:(1) the organic carbon pool of China’s wetlands is between 5.39 and 7.25 Pg,accounting for 1.3%-3.5% of the global level;(2) the estimated values and percentages of the organic carbon contained in the soil,water and vegetation pools in China’s wetlands are 5.04-6.19 Pg and 85.4%-93.5%,0.22-0.56 Pg and 4.1%-7.7%,0.13-0.50 Pg and 2.4%-6.9%,respectively.The soil organic carbon pool of China’s wetlands is greater than our previous estimate of 3.67 Pg,but is lower than other previous estimates of 12.20 and 8-10 Pg.Based on the discussion and uncertainty analysis,some research areas worthy of future attention are presented.     

自支撑矩形缩放管壳侧不同插入物的强化传热效果

利用数值模拟方法研究了湍流状态(雷诺数Re变化范围为27900 ～41900)下自支撑矩形缩放管换热器壳程内插入不同插入物(圆环和折板)后的传热性能与流动特性,并将壳程通道内插入圆环和折板后得到的结果与缩放管空管(无插入物)的结果做比较.结果表明:插入物的加入引起了通道内流体的速度及温度分布变化,从而产生传热及流动特性的变化;插入圆环和折板后壳侧的传热系数分别比缩放管空管时增加了16.69％ ～24.32％和38.01％～46.74％;在插入插入物后,传热系数增加的同时也引起了通道内压降的增大,与缩放管空管时比较,插入圆环和折板情况下压降增加的比例分别为74.02％～89.50％和68.49％～87.16％;插入折板后壳程通道内的综合传热性能最好,其次是插入圆环后,缩放管空管时最差.研究还发现,要提高换热器的传热性能,关键是要改善通道两侧缩放管处的传热性能,而从场协同角度对三者进行分析则发现,减小速度矢量与温度梯度矢量间的夹角是增强换热器传热性能的一个重要措施.     

精细计盒维数与连续函数图象

将分形理论中的一个重要概念计盒维数推广为精细计盒维数，给出了精细(下)计盒维数的等价表示，且讨论了连续函数图象的精细(下)计盒维数用函数空间刻划的充要条件．     

物料需求计划算法的改进

针对大运算量的传统物料需求计划算法不能够清晰地反映不同品种或型号间产品的需求信息的不足 ,提出了BOM中心算法 .该算法从整体性和系统性出发 ,运用面向对象设计思想以及虚拟提前期和虚拟结构数量的概念 ,运算层次清晰、运算速度快 ,比传统物料需求计划具有更强的可靠性和实用性     

Influence of extreme weather and meteorological anomalies on outbreaks of influenza A (H1N1)

Biological experiments and epidemiological evidence indicate that variations in environment have important effect on the occurrence and transmission of epidemic influenza.It is therefore important to understand the characteristic patterns of transmission for prevention of disease and reduction of disease burden.Based on case records,we analyzed the environmental characteristics including climate variables in Changsha,and then constructed a meteorological anomaly susceptive-infective-removal (SIR) model on the basis of the results of influenza A (H1N1) transmission.The results showed that the outbreak of influenza A (H1N1) in Changsha showed significant correlation with meteorological conditions;the spread of influenza was sensitive to meteorological anomalies,and that the outbreak of influenza A (H1N1) in Changsha was influenced by a combination of absolute humidity anomalous weather conditions,contact rates of the influenza patients and changes in population movements.These findings will provide helpful information regarding prevention strategies under different conditions,a fresh understanding of the emergence and re-emergence of influenza outbreaks,and a new perspective on the transmission dynamics of influenza.     

凯里动物群中Scenella的再研究

研究了贵州台下中寒武统凯里组产出的凯里动物群中的Ｓｃｅｎｅｌｌａ，据其形态，构造及保存特征，认为Ｓｃｅｎｅｌｌａ应属单板类。指出其与毛家仁等（１９９４）所定的Ｓｃｅｎｅｌｌａ ｒａｄｉａｎｓ Ｂａｂｃｏｃｋ ｅｔ ｒｏｂｉｓｏｎ 及Ｂａｂｃｏｃｋ和Ｒｏｂｉｓｏｎ（１９８８）定的Ｓｃｅｎｅｌｌａ ｒａｄｉａｎｓ Ｂａｂｃｏｃｋ ｅｔ Ｒｏｂｉｓａｎ有所区别，据此建立一新种。     

抗菌肽琼脂糖孔穴扩散法与比浊法测活比较及其相关性

以大肠杆菌Ｋ１２Ｋ３１为标准菌株，采用琼脂糖孔穴扩散法和比浊法相结合，对抗菌活性活力进行测定。通过细菌浓度的变化和抑菌圈大小来确定样品的活力单位，生物统计结果表明，活力单位（ｕ）与抑菌属直径（ｄ）两者之间存在定量在正相（ｕ＝０．０６ｄ）。     

吉祥数字:当代中国数字崇拜的文化解读

数字除了基本的计数功能外,人们还赋予了它更多的文化隐喻、哲学意义及宗教意义。而吉祥数字,就是数字中某些被人认为可以趋吉避害,带来吉祥的数字。在当代社会中,伴随经济社会发展而来的吉祥数字崇拜现象值得我们深思。从文化功能、价值取向、社会心理三方面解读"吉祥数字"的崇拜可以客观认识中国传统文化对当代的影响。     

速度欺骗干扰对反舰PD导引头的相干视频仿真

现有的末制导雷达电子干扰仿真评估试验对弹道解算模型进行了较大简化,普遍采用质点模型,使得仿真结果严重失真.讨论了六自由度闭环弹道仿真中的脉冲多普勒雷达导引头(PDRS)相干视频仿真,并针对典型的速度波门拖引干扰场景进行了仿真试验.结果表明速度波门拖引干扰对角度跟踪回路无直接影响,仅影响了角速度估计的收敛性,导致制导精度并无太大变化.该结论和暗室测量结果相吻合,表明PDRS相干视频模型用于6自由度闭环弹道仿真非常准确,为战术巡航导弹的参数设计和性能评估提供了一个有效和实际的解决方案.