贝塔系数的均值回归过程

CAPM中的贝塔系数被认为是证券组合和单个证券风险大小的衡量指标,近年来理论界对于CAPM中的贝塔系数并非常数已经达成了共识,而且众多迹象表明,贝塔系数的变化很可能遵循一个均值回归过程。本文的主要目的即以深发展为例,检验其贝塔系数是否遵循一个均值回归过程

智能制造刀具管理系统及刀具剩余寿命监测功能开发

伴随智能制造技术的深入推进,刀具管理系统的功能根据用户业务需求在不断拓展。针对工艺设计后的刀具选购、使用直至报废等环节,基于\"刀具流\"开发了一款智能制造刀具管理系统,更精确地实现了刀具使用过程的数字化、网络化、智能化和可视化全生命周期管理。鉴于目前刀具状态监测技术的复杂和可靠性低等问题,在工程应用上提出了一种基于被加工工件表面粗糙度间接预测刀具剩余寿命的方法。整个系统在现场得到了良好应用。2016年工信部智能制造综合标准化与新模式应用项目(工信部联装[2016]213号);;国家自然科学基金项目(51605403);;福建省产业技术联合创新专项(闽发改投资[2016]482号

Selective hydrogenolysis of sorbitol on Ni/La202CO3 catalysts

采用共沉淀法制各了具有协同稳定作用的Ni/La2O2CO3催化剂，用于山梨醇选择性氢解为小分子醇的研究。采用X射线衍射、氢气程序升温还原、C02程序升温脱附和扫描电镜对催化剂进行了表征。考察了不同配比Ni、La的加氢位点和碱性调控对山梨醇氢解产物的影响。结果表明，Ni、La摩尔比为2：3时，山梨醇转化率达到98.6%，C2~c3多元醇的产率达到43.8%，催化剂经2次反应后对山梨醇的转化率仍高达90%。探究了催化剂从酸性到碱性调变过程中，山梨醇氢解的产物分布，并提出了反应路径

HPLC测定乳痛消Ⅱ号中橙皮苷的含量

甘肃省科委资助项目 (No :GS 992 A4 3 0 70

贝塔系数波动状况的实证分析

资本资产定价模型(CAPM)自创立以来得到广泛应用。但对CAPM的实证检验也争议不断。利用上海股票市场90家上市公司的数据作为样本,对CAPM中的贝塔系数的波动状况进行实证研究,结果表明所有股票的贝塔系数波动率都显著异于零,贝塔系数在不同的时期会发生变化。实证分析中如果忽略了这一点,必将导致对CAPM检验的失效

中美主播跨洋对话的全球传播效果——一次中国全球媒介事件的案例分析

本文作者作为CGTN国际传播课题组成员,采用案例研究的方法,把发生在2019年5月的"中美主播跨洋对话"作为一次融媒体时代中国全球传播的重大媒介事件,对参与此次跨洋对话的亲历者和组织者进行了深入采访,跟踪比较了事件前后CGTN有关中美贸易战的传播内容和效果,记录分析了本事件发展过程中诸多重要的全球传播数据,并从媒介事件的发展创新视角,分析了跨洋对话的国际传播效果。本文从全球媒体影响力评估、全球区域影响力分析、社交媒体影响力以及全球媒体报道内容角度,对此次中美主播跨洋对话的传播效果进行解读分析

Effects of electropuncture of acupoints on the foot Yangming stomach meridian on metabolic profiling of gastric mucosa in gastric ulcer rats

目的:采用核磁共振氢谱技术(1H; NMR)研究电针胃经穴对应激性胃溃疡大鼠胃黏膜组织代谢物谱的表达。方法:40只SD大鼠随机分为正常组、模型组、胃经组和胆经组。利用束缚-冷应激法; 制备应激性胃溃疡模型大鼠,光镜下观察大鼠胃黏膜组织病理形态学的变化,采用1H NMR技术获取胃黏膜组织1H; NMR谱,并利用模式识别方法分析各组间的代谢物谱的差异。结果:与正常组比较,模型组大鼠胃黏膜损伤和胃黏膜组织代谢轮廓差异明显,胃黏膜组织乙酸、肌; 醇、磷酸胆碱、谷氨酸、甘氨酸、乙醇胺、赖氨酸、3-羟基丁酸、缬氨酸、异亮氨酸、牛磺酸、亮氨酸和甘露醇含量上升(P<0.05),乳酸、甲硫氨酸和天; 冬氨酸含量下降(P<0.05);与模型组比较,胃经组和胆经组大鼠胃黏膜得到明显修复,胃经组大鼠胃黏膜组织代谢轮廓更接近正常大鼠,胃黏膜组织甲硫氨; 酸、天冬氨酸含量上升(P<0.05),乙酸、肌醇、磷酸胆碱、谷氨酸、甘氨酸、赖氨酸、异亮氨酸、牛磺酸、乳酸、亮氨酸和甘露醇含量下降(P<0.05; );胆经组大鼠胃黏膜组织3-羟基丁酸、甲硫氨酸含量上升(P<0.05),肌醇、磷酸胆碱、谷氨酸、乙醇胺、异亮氨酸、乳酸、亮氨酸和甘露醇含量下降(; P<0.05)。结论:电针胃经穴可调节胃溃疡大鼠胃黏膜组织特异代谢物的表达,促进胃黏膜损伤的修复。Objective: To research the effects of electropuncture of acupoints on; the foot Yangming stomach meridian on metabolic profiling of gastric; mucosa in rats of gastric ulcer induced by stressusing the 1H nuclear; magnetic resonance (1H NMR). Methods: Forty SD rats were randomly; divided into the control group, the model group, the stomach meridian; group and the gallbladder meridian group. The rat model of gastric ulcer; was induced by the restrained plus cold stress. The pathological changes; in the rat gastric mucosa tissue were observed by light microscope. The; 1H NMR spectroscopy was determined with the 1H NMR technique. And,; meanwhile the differences in the metabolic profiling were identified; with the pattern recognition method. Results: Compared to normal group,; the gastric mucosa damage and gastric mucosa metabolic profiling are; obvious, the concentration of acetic acid, choline, inositol phosphate,; glutamic acid, glycine, ethanolamine, lysine, 3-hydroxy butyric acid,; valine, isoleucine, taurine, leucine and mannitol increase and the; concentration of lactic acid, methionine and aspartic acid decrease in; model group rats (P<0.05). Compared to model group, the gastric mucosa; damage have been recovered in stomach meridian group and gallbladder; meridian group, the metabolic profiling of gastric mocusa tissue in; stomach meridian group are similar to the normal group. The; concentration of methionine, aspartic acid increase and acetic acid,; choline, inositol phosphate, glutamic acid, glycine, lysine, lactic; acid, leucine, isoleucine, taurine, and mannitol decrease in stomach; meridan group (P<0.05). The concentration of 3-hydroxy butyric acid,; methionine increase and choline, inositol phosphate, lactic acid,; leucine, isoleucine, glutamic acid, ethanol amine and mannitol decrease; in gallbladder meridian group (P<0.05). Conclusion: The electropuncture; of acupoints on the foot Yangming stomach meridian could regulate the; metabolic profiling of gastric mucosa, resulting in improving the; gastric mucosa repair of gastric ulcer rats.国家自然科学基金项目; 国家重点基础研究发展计划(973计划)项目; 广东省自然科学基金项目; 深圳市科技计划项

个人投资者交易行为研究——来自台湾股市的证据

本文基于台湾股市数据,主要研究个人投资者的交易行为。参照Kaniel et al.(2008)构建了个人投资者交易不平衡性指标─净交易,以反映投资者股票交易的强度。采用这种交易不平衡性指标来构建投资组合研究个人投资者的交易行为。首先研究个人投资者交易和股票的收益之间的动态关系从而分析投资者的交易策略,然后研究个人投资者净交易的收益预测能力从而分析个人投资者交易的信息含量。本文研究发现:台湾股票市场的个人投资者采用负反馈的交易策略,并且个人投资者在交易中表现出很强的处置效应;个人投资者在交易中的信息含量不足;个人投资者交易中的盈利主要来自两个方面:过度反应和价格冲击。文章最后给出政策建议

Calculation of passive earth pressures on retaining wall considering soil arching effects of backfill clayey soil

为解释挡土墙后填土被动土压力的非线性分布现象,在考虑土拱形状为圆弧,滑裂面采用朗肯滑裂面的基础上,给出考虑土拱效应的被动土压力系数kAWn,进而基于应力状态法及土楔形体静力平衡两种思想求解了竖向平均应力V？公式,在该基础上,给出黏性土填料下的挡土墙被动土压力分布公式、合力公式及作用点高度计算公式。通过与试验与其他方法对比,文中提出的方法得到验证。最后,研究了黏性土填料下的挡土墙被动土压力变化规律,即考虑土拱效应求得的黏性土填料的被动土压力分布呈现上小下大的指数型分布。此外,随着δ/φ(δ为墙土摩擦角,φ为内摩擦角)的增大,土拱效应逐渐增强,土压力合力点逐渐降低。The nonlinear phenomenon which the passive earth pressure behind the retaining wall of both sand and cohesive soil is nonlinear distribution could be explained by the soil arching effect theory.The formula which calculated passive earth pressure coefficient of which assumed the stress state method and the soil wedge static equilibrium method were derived considering the soil arching effect, assumed arch as circle and the angle of slip surface as Rankine's theory.Then, the distribution of lateral earth pressure considering the soil arching was derived by the above formulations; also the formulas that calculating the magnitude and the point of application of lateral passive earth pressure were derived.The accuracy of proposed method is confirmed by comparing with the experimental tests and values from existing equations.Finally, the trends of distribution and the height of total passive earth pressure of clayey soil are studied; distribution of passive earth pressures considering the soil arching is likely an exponential curve; and the height of resultant earth pressure point is gradually reducing with increasing the ratio of soil-wall friction angle to internal angle δ/φ.国家自然科学基金资助(No.51209180); 浙江省自然科学基金资助(No.Y1091175