房地产价格指数与居民消费水平的动态回归分析

以SAS软件为工具,对郑州市2009年5月至2013年5月新建住宅价格指数序列和居民消费价格指数序列进行协整分析,分别拟合了动态回归ARIMAX模型和误差修正ECM模型.ARIMAX模型显著有效,揭示了居民消费价格指数对新建住宅价格指数的影响系数达到1.014 73,预测结果显示,郑州市的房价近期仍呈上升态势,上涨幅度维持在1%左右.ECM模型拟合效果不理想,说明房价受短期波动的影响很小,对房地产市场的调控漫长而复杂.     

最小二乘支持向量机在API预测中的应用

传统的空气污染指数预测模型大多是以影响空气污染指数的重要气象因子作为输入,使用BP神经网络进行建模,模型的预测精度低且收敛速度慢.针对空气污染指数时间序列的非线性及多分辨率特性,提出了一种空气污染指数的最小二乘支持向量机预测模型.首先利用小波变换对原始的空气污染指数时间序列进行多尺度分解,以各尺度上的小波单支重构序列和重要的气象因子作为输入,然后使用该模型对兰州地区的空气污染指数进行了预测,最后讨论了模型参数的优化方法并使用网格法对两个参数进行了优化.仿真结果表明,与传统的BP神经网络预测模型相比,该模型具有更高的预测精度、更快的收敛速度及更好的稳定性.     

限食对谷氨酸钠肥胖大鼠及人体肥胖代谢指标的影响

目的 观察短期限食对肥胖人群及大鼠脂肪代谢指标的影响.方法 动物实验:将谷氨酸钠肥胖大鼠分为对照组和限食组,并分别观察两组体重、Lee指数、脂肪指数和甘油三酯的变化;人体实验:受试者为21名女性,年龄22～45岁.限食者均限食7天,第1天为缓冲日,第2～6天为禁食日,第7天为恢复日.观察限食前后体脂、体脂百分率、体重、BMI和腰围的变化.结果 谷氨酸钠肥胖大鼠限食组体重、Lee指数、脂肪指数和甘油三酯与对照组相比明显下降,并且具有显著性差异(p＜0.01).21名受试者在限食前后体脂、体脂百分率和腰围差异有统计学意义(p＜0.05),体重和BMI下降差异有显著统计学意义(p＜0.01).结论 限食疗法对于肥胖症治疗及并发症预防具有重要意义.     

碱金属硝酸盐在1,2-丙二醇—水混合溶剂中15℃和45℃的溶解行为研究

采用自制的相平衡研究装置,用密度-折光率联合的方法,测定了碱金属硝酸盐在1,2-丙二醇/水(0～1)混合溶剂中15℃和45℃时的平衡溶解度.利用DMA4500密度计和RXA170折光率仪测定了饱和溶液15℃和45℃下的密度和折光率.实验结果表明,随着混合溶剂中1,2-丙二醇含量增加,碱金属硝酸盐的溶解度降低.饱和溶液的密度随着混合溶剂中1,2-丙二醇含量的增加而减小,但折光率却呈现出增加的趋势.用四参数经验关联方程对所有饱和体系的溶解度、折光率及密度数据进行了拟合.盐析率结果表明,1,2-丙二醇对碱金属硝酸盐都有盐析作用,温度升高,盐析率稍微增大.     

隧道施工地层危险性评估模型研究

随着交通基础设施建设的大规模展开,对隧道工程需求量越来越大,隧道施工中的安全和风险控制问题变得更加突出。不利地层条件一直是影响隧道施工安全和风险的关键因素。利用相互作用矩阵确定各个主要地层参数的相对权重,采用概率方法和Monte Carlo模拟技术处理地层参数取值的不确定性,提出地层危险性指数计算公式和地层危险性等级划分方法,建立隧道施工地层危险性评估模型,并对不同地层危险性等级隧道施工风险管理的原则性对策提出建议。     

关于f(k)fn的值分布

利用Nevanlinna值分布理论,讨论了f(k)fn的值分布,推广了Hayman、仪洪勋和叶寿桢等人的相关结果.     

不同行业工业用地集约利用水平比较研究——以江苏省典型区域为例

研究目的：通过对不同行业工业用地集约利用水平的测算,揭示其集约利用水平及其差异性;研究方法：以江苏省典型城市为研究区域,在工业企业调研的基础上,通过建立不同行业工业用地集约利用评价指标体系,评价研究区域工业行业用地集约利用水平;研究结果：江苏省典型区域不同行业工业用地集约利用水平存在显著差异,其中交通运输设备制造业、纺织服装、鞋、帽制造业、通信设备、计算机及其他电子设备制造业的用地集约水平最高,而医药制造业、专用设备制造业用地集约水平较低;研究结论：根据集约用地评价结果,对江苏省工业行业采取针对性的措施提高其集约利用水平,以缓解江苏省经济社会发展过程中人多地少的矛盾,为经济的进一步快速发展提供条件。     

Characterstics of seasonal variations of leaf n-alkanes and n-alkenes in modern higher plants in Qingjiang, Hubei Province, China

On the basis of GC and GC-MS analyses, the seasonal variation of leaf lipids is observed in five plant species in Qingjiang in Hubei Province. The CPI values （carbon preference index） of n-alkanes decrease gradually from May to November, though the carbon number distributions and the predominant carbon number in an individual species keep unchanged. The declined CPI values might be caused by the leaf fading, which is further supported by a comparison of the defoliated leaves with the fresh leaves. This observation infers the CPI values of n-alkanes in Quaternary sediments can be used as a tool to index the humification, and thus the climatic and the environmental conditions. The plants analyzed here show a remarkable difference in n-alkanes abundance, suggesting their differential contribution to the n-alkanes identified in sediments. The abundance and the compound species of the n-alkenes detected in the plant leaves change greatly with the seasons due to the influence of temperature, with the least compounds being identified in August.     

Structures of magnetic null points in reconnection diffusion region: Cluster observations

Magnetic reconnection is a very important and fundamental plasma process in transferring energy from magnetic field into plasma. Previous theory, numerical simulations and observations mostly concentrate on 2-dimensional （2D） model; however, magnetic reconnection is a 3-dimensional （3D） nonlinear process in nature. The properties of reconnection in 3D and its associated singular structure have not been resolved completely. Here we investigate the structures and charactedstics of null points inside the reconnection diffusion region by introducing the discretized Poincar6 index through Gauss integral and using magnetic field data with high resolution from the four satellites of Cluster mission. We estimate the velocity and trajectory of null points by calculating its position in different times, and compare and discuss the observations with different reconnection models with null points based on characteristics of electric current around null points.     

Relationship between Chinese speech intelligibility and speech transmission index in rooms using dichotic listening

Speech intelligibility （SI） is an important index for the design and assessment of speech purpose hall. The relationship between Chinese speech intelligibility scores in rooms and speech transmission index （STI） under diotic listening condition was studied using monaural room impulse responses obtained from the room acoustical simulation software Odeon in previous paper. The present study employs the simulated binaural room impulse responses and auralization technique to obtain the subjective Chinese speech intelligibility scores using rhyme test. The relationship between Chinese speech intelligi-bility scores and STI is built and validated in rooms using dichotic （binaural） listening. The result shows that there is a high correlation between Chinese speech intelligibility scores and STI using dichotic listening. The relationship between Chinese speech intelligibility scores and STI under diotic and dichotic listening conditions is also analyzed. Compared with diotic listening, dichotic （binaural） listening （an actual listening situation） can improve 2.7dB signal-to-noise ratio for Mandarin Chinese speech intelligibility. STI method can predict and evaluate the speech intelligibility for Mandarin Chinese in rooms for dichotic （binaural） listening.