英国的石油法治体系及其对中国的启示

油气等能源资源是发展经济的重要物质基础,在国家经济体系中占有战略地位。随着中国对能源需求的稳步增长,油气对外依存度也不断攀升。中国的油气企业应走出去,开展国际能源合作以保障国内的能源安全。在对外能源合作中,要学习西方发达国家的石油法治体系,借鉴它们管理油气行业的成功经验。英国对石油的商业开采历史悠久,实践经验丰富,逐渐形成了涵盖海陆油气开发、独具特色、较为完整的石油法治体系。学习和借鉴英国油气立法的先进理念、完善的法治体系及切实可行的矿业权管理制度具有重要的理论和现实意义。     

熔盐泵内颗粒属性对固液两相流动的影响

熔盐泵工作环境的特殊性会导致泵内含有熔盐小颗粒,这些小颗粒使泵性能下降,并降低过流部件寿命。为探 究熔盐泵输送两相介质时的性能,基于Eulerian多相流模型和标准K-8湍流模型,采用FLUENT软件对不同的颗粒属性 （粒径、体积分数、密度）产生的影响做了研究。结果表明：颗粒对泵流动产生了较为明显的影响,粒径越大的颗粒在工 作面处的体积分数越高,固相离析作用也越来越明显。泵内部存在一些体积分数与进口颗粒体积分数相等的点,这些点 形成的曲面的形状和位置不随颗粒的属性改变而改变。这些曲线的形状和位置可用来判断泵内流动的状态和泵结构设 计的合理性。该研究发现的一种全新的两相流现象,可用于初步判断固液两相流泵的水力性能。     

适时介入、市场重塑与协同创新--奥巴马政府的汽车产业政策分析

在2008—2009年的经济危机中,美国的汽车产业遭受了严重冲击,为此奥巴马政府出台了积极的汽车产业政策。通过从救助汽车企业和扶助汽车产业发展2个维度的考察发现,在救助濒临破产企业时,政府一度介入企业的管理决策。而在扶助汽车产业时,政府加大公共投资,形成投资驱动;研发政策带动科技创新,形成创新驱动;通过规则制定、消费引导和联邦政府采购等政策,形成了政策驱动。奥巴马政府的汽车产业政策跨越了倡议和引导,进入了政府协同汽车产业发展的阶段。基于上述分析,可进而研究奥巴马政府的汽车产业政策特征。研究表明：这一政策既具有往届政府产业政策的固有特征,如以问题为导向、市场化运作以及以法律为依据等。同时,也具有定位产业方向和更注重研发与创新等新特征。探讨奥巴马政府的汽车产业政策,可为中国目前的产业政策调整提供借鉴。     

Maximum likelihood estimator in a multi-phase random regression model

We consider a random regression model with several-fold change-points. The results for one change-point are generalized. The maximum likelihood estimator of the parameters is shown to be consistent, and the asymptotic distribution for the estimators of the coefficients is shown to be Gaussian. The estimators of the change-points converge, with n ^?1 rate, to the vector whose components are the left end points of the maximizing interval with respect to each change-point. The likelihood process is asymptotically equivalent to the sum of independent compound Poisson processes.     

企业规模与竞争关系网络互动关系实证研究——以中国啤酒企业为例

从复杂网络和计量经济的交叉视角研究企业相互间的竞争关系。通过企业度、平均路径长度与集聚系数3个拓扑属性,分析网络演化过程中企业规模与竞争关系网络的互动关系;以2000年、2006年和2012年中国啤酒企业竞争关系网络为对象进行实证研究,采用网络中的拓扑属性为自变量,建立了关于企业规模的计量经济模型。研究结果表明:(1)企业规模与节点平均路径长度及其集聚系数表现出正相关性,与节点的度呈负相关性;(2)啤酒企业竞争由无序局面,逐渐形成了"四极多核"的格局:企业竞争极化现象主要集中在第1梯队(雪花、青岛、燕京及百威英博),多核化竞争发展趋势呈现于第2梯队。     

Penalized weighted composite quantile regression in the linear regression model with heavy-tailed autocorrelated errors

In this paper, a penalized weighted composite quantile regression estimation procedure is proposed to estimate unknown regression parameters and autoregression coefficients in the linear regression model with heavy-tailed autoregressive errors. Under some conditions, we show that the proposed estimator possesses the oracle properties. In addition, we introduce an iterative algorithm to achieve the proposed optimization problem, and use a data-driven method to choose the tuning parameters. Simulation studies demonstrate that the proposed new estimation method is robust and works much better than the least squares based method when there are outliers in the dataset or the autoregressive error distribution follows heavy-tailed distributions. Moreover, the proposed estimator works comparably to the least squares based estimator when there are no outliers and the error is normal. Finally, we apply the proposed methodology to analyze the electricity demand dataset.     

《说文解字诂林》引经类文献略考

《说文解字诂林》引经类文献有21种。文章对这些文献进行目录学梳理,并从考辨字形、训释字义以及形义兼考三个方面对其分类,考察其特点,认为,这些文献反映了清儒对《说文》引经问题以及经学训诂与小学训诂差异的认识,其研究方法与结论对后世研究《说文》引经问题很有启发。     

Some properties of generalized ridge estimators

Exact expressions, in the form of infinite series expansions, are given for the first and second moments of two well known generalized ridge estimators. These series expansions are then evaluated using recursive formulas and computations are verified using approximations. Results are presented for the relative mean square error and bias of these estimators as well as their relative efficiency with respect to least squares.     

Ordinary least squares estimation of the functional errors-in-variables model with trended data:some monte carlo evidence

This note summarizes some Monte Carlo experiments that were designed to investigate the finite sample relevance of the asymptotic normality and efficiency of OLS in the errors-in-variables model with trended data. The experiments show that the normal approximation is not very satisfactory for sample size up to T=400, but that OLS is quite efficient relative to competing estimators when there is a trend in the exogenous variables of the model.     

On the Ratio of Two Folded Normal Distributions

A class of distributions associated with the ratio of two folded normal random variables is introduced which strictly includes the half standard Cauchy distribution. The properties of this class of distributions are studied, along with a graph of the possible shapes of its density functions. The salient features of this class are mathematical tractability and statistical applicability. Utility of the class of distributions is demonstrated by presenting four applications.