加权Dirichlet空间之间的总体紧复合算子列

设φn：Ｄ→Ｄ为解析映射列,作者详细讨论了加权Dirichlet空间之间复合算子列｛Ｃφn｝的总体紧性,得到以下主要结论：(i) 当Ｃφn:D２α→D２β（α,β＞０）为一致有界复合算子列时,｛Ｃφn｝总体紧的充要条件;(ii) 当Ｃφn：D２α→D２β（α,β≥１）一致有界复合算子列时,｛Ｃφn｝总体紧的充要条件     

口头明了的反馈——大学英语教学作文批改方法改革的实验研究

批改作文的方式按实施者划分,可分为四种：教师批改、学生自改、同学互改、集体批改。但它们有利有弊,效果都不令人满意。目前国外盛行一种批改方法：讨论会（Conferencing）,它的一个明显的特点“口头明了的反馈”（Oral Explicit Feedback）,与书面的反馈相比,更人性化,形象化进而使人印象深刻。实证研究证明：通过在作文批改中运用口头明了的反馈,实验组的语法错误的更正率比对照组的有明显提高。     

Improvement of xylanase production by Aspergillus niger XY-1 using response surface methodology for optimizing the medium composition

Objective： To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation （SSF）. Methods： Statistical methodology including the Plackett-Burman design （PBD） and the central composite design （CCD） was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. Results： Firstly, NaNO3, yeast extract, urea, Na2CO3, MgSO4, peptone and （NH4）2SO4 were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization. Finally, the CCD and response surface methodology （RSM） were applied to determine the optimal concentration of each significant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by multiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows： x1 （urea）=0.163 （41.63 g/L）, x2 （Na2CO3）=-1.68 （2.64 g/L）, X3 （MgSO4）= 1.338 （10.68 g/L） and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. Conclusion： By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization.     

蒙药那如-3的研究进展

综述了近年来常用蒙药那如-3的化学成分、药理作用等方面的研究进展．     

山东省社会经济与生态环境协调发展的综合分析与评价

从生态经济学和社会经济学原理出发,运用PREEST系统模型,建立了山东省生态环境、经济系统的综合评价指标体系．借助于主成分分析法,初步评价了1996-2005年期间山东省生态环境、经济系统的综合发展状况．通过回归拟合和协调指数计算,对山东省生态环境、经济系统发展的协调状况进行了定量分析,并提出了解决有关问题的几点建议．     

支持动态服务组合的Web服务封装

针对如何将包含复杂操作的Web服务封装成Web服务社区和Web服务簇这一问题,提出一种基于Web服务日志,使用序列模式挖掘技术的Web服务封装方法.该方法对Web服务日志进行序列模式挖掘以获得业务功能服务序列,使用获得的序列将Web服务封装成业务功能服务,进而封装成服务社区和服务簇.使用该方法可以有效地将包含复杂操作的Web服务封装成支持动态服务组合的服务社区和服务簇.     

The importance of the forecast

Careful forecasts, as accurate as possible, are central to the successful implementation of policy. There are fundamental reasons why policy makers cannot ‘play by ear’, adjusting policy quickly to each unexpected deviation in economic outcomes. Specific incidents are described where economic policy went awry because of faulty forecasts. The policy process is described in detail to show precisely where the forecast enters. Forecasting as a validation tool for establishing credibility in policy formation is analysed and discussed. Some estimated measure of forecast accuracy is presented, together with commentary on the necessary degrees of precision for successful implementation of policy.     

Linear combination of forecasts with an intercept: A bayesian approach

The standard approach to combining n expert forecasts involves taking a weighted average. Granger and Ramanathan proposed introducing an intercept term and unnormalized weights. This paper deduces their proposal from Bayesian principles. We find that their formula is equivalent to taking a weighted average of the n expert forecasts plus the decision-maker's prior forecast.     

铁镍锌离子对阴极铜沉积反应的影响

利用电导仪及电子能谱等仪器,并采用稳态法研究了铁、镍、锌离子对酸性硫酸铜电解液系统中阴极铜沉积反应的影响。研究结果表明：铁镍锌离子存在于电解液中,增大溶液电阻,减小溶液电导率,减小铜沉积反应的交换电流密度和极限电流密度,对铜沉积反应起极化作用。但铁、镍、锌离子几乎不影响电荷传递系数,不改变铜沉积反应机理。在２００Ａ·ｍ－２和１０００Ａ·ｍ－２电流密度下电解,铁、镍、锌不会在阴极沉积。在阴极铜沉积层中铜主要以金属铜和少量Ｃｕ２Ｏ形式存在。     

花鳗鲡和日本鳗鲡肌肉生化成分的比较研究

对花鳗鲡肌肉生化成分进行定量分析,结果表明：（1）花鳗鲡鲜肉中蛋白质含量为11．44％,脂肪5．08％,水分77．94％,是一种高蛋白低脂肪的鱼类。（2）花鳗鲡鲜肉中含18种氨基酸,总量为49．95％,其中含有8种人体必需氨基酸,总量为19．32％;具鲜甜味的天门冬氨酸、谷氨酸、丙氨酸和甘氨酸分别占鲜肉氨基酸总量的9．89％、19．80％、6．07％和5．43％。可认为是一种氨基酸组份较齐全、味鲜美的珍贵食用鱼类。进一步与日本鳗鲡比较,表明：花鳗鲡的营养价值优于日本鳗鲡;花鳗鲡和日本鳗鲡肌肉中氨基酸组份和含量高低相似;日本鳗鲡的氨基酸总量高于花鳗鲡。本研究可为花鳗鲡的种质鉴定、资源保护开发和养殖饲料配制等提供科学依据。