正态分布下任意秩有限总体中的Minimax预测

对于任意秩有限总体,在二次损失下,有关文献已给出了线性可预测变量在齐次线性预测类中的唯一线性Minimax预测．本文在正态假设下,证明了这个线性Minimax预测也是线性可预测变量在一切预测类中的唯一Minimax预测．     

基于TRNSYS的太阳能集热系统能量转化分析与优化

建立了太阳能集热器非稳态数学模型。以工程实例为研究对象,借助于TRNSYS软件,分析不同集热器类型,集热面积,水箱容积,水箱流量对太阳能集热系统性能的影响。优化集热器和水箱设计参数,采用变流量水箱系统,对提高太阳能集热系统综合性能有指导意义。     

Analytic Solution of Charge Density of Single Wall Carbon Nanotube under Conditions of Field Electron Emission

We derive the analytic solution of induced electrostatic potential along single wall carbon nanotubes. Under the hypothesis of constant density of states in the charge-neutral level, we are able to obtain the linear density of excess charge in an external field parallel to the tube axis.     

Two New Eremophilenolides from Ligularia muliensis

Many Ligularia species have long been used as traditional folk medicine for theirantibiotic, antiphlogistic and antitussive activities1, and were found to be an importantsource of eremophilane. In the course of our search for bioactive sesquiterpenoids, w…     

Frequency Selectivity Behaviour in the Auditory Midbrain： Implications of Model Study

By numerical simulations on frequency dependence of the spiking threshold, i.e. on the critical amplitude of periodic stimulus, for a neuron to fire, we find that bushy cells in the cochlear nuclear exhibit frequency selec- tivity behaviour. However, the selective frequency band of a bushy cell is far away from that of the preferred spectral range in human and mammal auditory perception. The mechanism underlying this neural activity is also discussed. Further studies show that the ion channel densities have little impact on the selective frequency band of bushy cells. These findings suggest that the neuronal behaviour of frequency selectivity in bushy cells at both the single cell and population levels may be not functionally relevant to frequency discrimination. Our results may reveal a neural hint to the reconsideration on the busily cell functional role in auditory information processing of sound frequency.     

多元线性回归法在互联网网间结算中的应用

本文建立一个理论模型研究互联网互联结算的问题。文章利用多元线性回归法对互联网骨干网运营商(IBPs:Internet Backbone Providers)的网络价值进行评估,利用IBPs各自的网络价值对其交换速率进行加权,从而得出网络价值加权速率,依据这个速率进行结算既可以反映了每个网络对互联的贡献程度,又反映了在互联中对网络资源的被占用程度。     

浅析英汉习语来源之共性

习语是一个民族智慧的结晶,是语言中的精华.凡历史悠久的语言无不有着内容丰富的习语.通过劳动和生活、神话和寓言、历史事件、宗教影响、文学语言、外来语的影响、科技的发展等不同层面,采用对比分析的方法,证实了英汉这两个分属于两个半球的语言,特别是习语,在产生的土壤、演化的历程和来源等方面有非常多的共性.     

Single Qubit and Its Universal Logic Gate Made of a Heisenberg Spin Cluster with Five Particles

We investigate an anisotropic Heisenberg spin cluster with five particles controlled by a time-dependent magnetic field. With the algebraic dynamical method, we obtain the exact analytical solution to the time dependent Schr6dinger equation. Based on the analytical solution, it is shown that the system can be used as a universal single qubit logic gate controlled by the strength and frequency of the magnetic field, and the six special single qubit logic gates can be realized physically. We also discuss the anti-decoherence property of the qubit and its logic gates resulted from particle coupling effect and collectivity of the cluster.     

Monte Carlo散射标记方法在辐射防护设计中的应用

在X射线检查系统中,辐射防护中除了需要重点考虑透射和漏射外,散射的成分也必须考虑,而且散射的影响变得越来越重要,这一点在同方威视的固定式、组合式和车载式系统中都已经得到了体现。针对散射的问题,该文进行了系统的研究,提出了在Monte Carlo计算中采用散射标记方法分析各散射体对于散射的贡献,克服了传统方法无法准确计算某一点的散射剂量率以及各散射体对散射的贡献的局限,并利用实验进行了验证。该文采用的计算工具是Geant4软件包。结果表明,该文提出的方法是可行的,尤其在复杂系统的辐射防护优化设计中具有较好的指导作用。     

论《沧浪诗话》的“师古”思想体系及其得失

本文从师法的对象——“以汉魏晋盛唐为师”、师法的原因——“盛唐诸人惟在兴趣”和师法的方法——从“识”到“妙悟”三个角度对严羽《沧浪诗话》“师古”思想体系进行了梳理和阐发,并对之作出了准确的特点、原创的意义和超越性的价值等正面评价以及矛盾、错讹和疏漏的负面评价。