非齐次动力方程Duhamel项的精细积分

提出了不需要矩阵求逆运算的求解Duhamel积分项的精细积分方法.通过将精细积分法的关键思想--加法定理和增量存储--直接应用于Duhamel积分响应矩阵的求解,可给出当非齐次项分别为多项式、正弦/余弦以及指数函数等基本形式时Duhamel积分在计算机上的精确解.特别的,该算法不依赖于系统矩阵(或相关矩阵)的形态.当系统矩阵奇异或接近奇异时,其优越性更为显著.算例验证了该算法的有效性.     

变量聚类—全局主成分分析在我国普通高等教育发展水平评价中的应用

本文根据1997年~2003年共同构成的关于我国普通高等教育发展水平的时序立体数据表,对各地区高等教育发展整体状况的各项指标进行变量聚类,以区分对我国高教发展背景与现状分别产生影响的各项指标,然后对每一类作主成分分析,选出能够代表该类的主成分。在此基础上,计算出各地区各年度主成分的增长度;再对各年度主成分的增长度作主成分分析,以期对我国高教发展背景与现状的总体变化趋势做出综合评价。     

动态规划的单增量搜索算法

本文首先对现有的三种动态规划迭代算法：微分动态规划、渐进优化算法、状态增量动态规划作了简单评述。针对如何进一步减少计算工作量和加快收敛速度，提出单增量搜索算法。通过理论阐述和实例分析，说明这种新的迭代算法优于上述三种常用方法。最后，本文把这种方法推广到连续型动态规划问题。     

时滞Duffing型方程周期解的存在唯一性

该文利用拓扑度方法研究了一类时滞依赖状态的广义Duffing型泛函微分方程x'(t)$ 该文利用拓扑度方法研究了一类时滞依赖状态的广义Duffing型泛函微分方程x'(t)$ 该文利用拓扑度方法研究了一类时滞依赖状态的广义Duffing型泛函微分方程x'(t) g(x(t-τ(t,x(t))))=f(t)周期解的存在性,得到了方程周期解存在的充分条件和必要条件．研究了当滞量为常值时,方程周期解的存在唯一性．并且给出了所研究问题的一个应用实例．     

Numerical treatment of retarded differential–algebraic equations by collocation methods

This paper investigates retarded differential–algebraic equations of index zero to two with state-dependent delay. The theory needed to understand the numerical approach and analyze the numerical treatment by collocation methods is developed. Different strategies for tracking the jump discontinuities are considered and numerical examples are presented to support the convergence results. This revised version was published online in August 2006 with corrections to the Cover Date.     

Short duration gamma ray bursts

After a short review of gamma ray bursts (GRBs), we discuss the physical implications of strong statistical correlations seen among some of the parameters of short duration bursts (T ₉₀ < 2 s). Finally, we conclude with a brief sketch of a new unified model for long and short GRBs.     

Heat capacity, enthalpy and entropy of strontium bismuth niobate and strontium bismuth tantalate

The heat capacities and enthalpy increments of strontium bismuth niobate SrBi₂Nb₂O₉ (SBN) and strontium bismuth tantalate SrBi₂Ta₂O₉ (SBT) were measured by the relaxation method (2–150 K), Calvet-type heat-conduction calorimetry (305–570 K) and drop calorimetry (773–1373 K). The temperature dependences of non-transition heat capacities in the form C_pm = 324.47 + 0.06371T − 5.0755 × 10⁶/T² J K⁻¹ mol⁻¹ (298–1400 K) and C_pm = 320.22 + 0.06451T − 4.7001 × 10⁶/T² J K⁻¹ mol⁻¹ (298–1400 K) were derived for SBN and SBT, respectively, by the least-squares method from the experimental data. Furthermore, the standard molar entropies at 298.15 K S_m°(SBN)=327.15±0.80 and S_m°(SBT)=339.23±0.72 J K⁻¹ mol⁻¹ were evaluated from the low-temperature heat capacity measurements.     

壳聚糖折光指数增量的研究

本工作制备了具有不同胺基含量的系列壳聚糖样品,测定和研究了它们的脱乙酰度(D.D.)和溶液拆光指数增量(dn/dc)。发现不同D.D.壳聚糖的dn/dc值不同,而且两者间符合二元无规共聚物的dn/dc值与其化学组成之间的一般线性关系,从而建立了一种可从dn/dc值分析测定壳聚糖的脱乙酰度的新方法。     

Influence of the time delay of signal transmission on synchronization conditions in drive-response systems

Conditions for complete and lag synchronizations in drive-response systems are considered under the unified framework of generalized synchronization. The question is addressed that whether the synchronization conditions achieving complete synchronization is still valid for lag synchronization when the time delay of signal transmission between the drive and response systems increases from 0. Theoretical and numerical results show that whether the synchronization conditions is stable for the influence of the time delay of signal transmission depends on a particular form of equilibria of the drive and response systems. Furthermore, it seems that the less the number of the equilibria of the drive system, the more likely the synchronization conditions are stable for the time delay of signal transmission.     

Thermal Gradients in TMDSC Samples: A comparison of theory and experimental data

Until recently, the issue of the thermal gradients within TMDSC samples remained mostly a subject of theory and mathematical models — only the phase lag was subject to experimental verification, as this information is readily available from the analysis software of most instruments. There was no method to verify the transient behaviour and temperature gradients within a sample without making costly and intensive modifications to the equipment. Recently, however, a group of researchers were able to experimentally measure thermal profiles as a function of sample thickness with a high-speed, high-resolution infrared camera mounted on the TMDSC cell. Therefore, this paper is dedicated to comparing the predictions of our three-dimensional model with this newly available data.This revised version was published online in November 2005 with corrections to the Cover Date.