The ordinary quiver of a weight three block of the symmetric group is bipartite

Suppose F is a field of characteristic p?5, and that B is a p-block of the symmetric group Sn of defect 3. We prove that the Ext¹-quiver of B is bipartite, with the bipartition being described in a simple way using the leg-lengths of p-hooks of partitions.     

Winograd矩阵乘法算法用于任意阶矩阵时的一种新处理方法

摘要t矩阵乘法StraSsen算法及其变形winograd算法用分而治之的方法把矩阵乘法时间复杂性由传统的D(n。)改进到0(佗kg。n.但是对于奇数阶矩阵,在划分子矩阵时,要作特殊处理才能继续使用此算法.本文提出了一种非等阶“十”字架划分方法,可以最少化填零,最大化性能,使得奇数阶矩阵乘法的时间复杂性更加接近偶数阶矩阵乘法的效果.计算实例显示该方法是有效的.     

Difference in micellar properties of sodium dodecyl sulfonate from sodium 4-decyl naphthalene sulfonate in D2O solution studied by 1H NMR relaxation and 2D NOESY

¹H chemical shift changes of sodium 4-decyl naphthalene sulfonate (SDNS) at 313 K show that its critical micellar concentration lies between 0.82 and 0.92 mmol/dm³, which is in the same range as that of the previous study at 298 K. The spin–lattice relaxation time, spin–spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy experiments give information about the structure of the SDNS micelle and the dynamics of the molecules in the micelle. The size of the SDNS micelle remains almost unchanged in the temperature range from 298 to 313 K as deduced by analyzing the self-diffusion coefficient. Special arrangement of the naphthyl rings of SDNS in the micelles affects the packing of these hydrophobic chains. The methylene groups of the alkyl chain nearest the naphthalene groups penetrate into the aromatic region, which results in a more tightly packed hydrophobic micellar core than that of sodium dodecyl sulfonate.     

CreditRisk+模型下商业银行经济资本配置研究

对金融资产风险的度量与经济资本的分配应该体现分散化效应,传统的V aR方式不能保证分散化效应的次可加性.本文讨论了基于T a ilV aR这一新的风险度量与经济资本分配标准,并在违约率均值不变情况下,对C red itR isk+模型下的商业银行经济资本分配进行了实证分析.     

Power scaling of printed-circuit-board preionized TEA CO2 laser up to 3.6 kW

A high average power, high-repetition-rate TEA CO₂ laser employing printed-circuit-board preionizer is described. The power scaling of this preionization configuration has been demonstrated. The average output power reaches 3.6 kW at pulse repetition rate of 180 pps. Furthermore, the scaling-up ability of the rotating spark gap as high-voltage switch for high-average-power gas laser has been validated.     

激光水下偏振特性用于目标图像探测

利用激光水下偏振特性获得偏振差分图像(PDI),并运用PDI技术,从理论和实验上对水下目标探测进行了研究.介绍了PDI基本概念和实验系统原理,然后比较分析了不同条件下普通图像与PDI在辨别目标距离及其纹理上的差别和PDI中背景偏振光的影响,得出利用目标和背景偏振光的差异区分二者,从而提高探测距离的结论,并取得了较好的效果.在此基础上提出了通过处理有关PDI偏振参量来进一步辨别目标与背景的设想.     

DUAL RECIPROCITY HYBRID BOUNDARY NODE METHOD FOR THREE-DIMENSIONAL ELASTICITY WITH BODY FORCE

Combining Dual Reciprocity Method （DRM） with Hybrid Boundary Node Method （HBNM）, the Dual Reciprocity Hybrid Boundary Node Method （DRHBNM） is developed for three-dimensional linear elasticity problems with body force. This method can be used to solve the elasticity problems with body force without domain integral, which is inevitable by HBNM. To demonstrate the versatility and the fast convergence of this method, some numerical examples of 3-D elasticity problems with body forces are examined. The computational results show that the present method is effective and can be widely applied in solving practical engineering problems.     

ClONO2异构化反应和分解反应的理论研究

用B3LYP/6 31+G(d)和MP2 (Full) /6 31+G(d)优化ClONO2 及其分解反应和异构化反应的过渡态和产物的分子结构 .在B3LYP/6 31+G(d)水平上计算了相关分子的振动频率 .ClONO2 的几何结构、振动频率和红外强度与实验测量值符合得很好 .找到了未曾报道的立体异构体 .对这一立体异构体进行了高级别理论方法CCSD(T) /6 311G(d)和QCISD(T) /6 311G(d)的几何结构优化和振动频率计算 ,表明它是一个稳定的立体异构体 .在所研究的几种反应中 ,ClONO2 分解为NO2 +ClO是最容易进行的反应 .而ClONO2 异构为立体异构体的反应是最难进行的反应 .其所需克服的过渡态的能垒为 4 81.5 2kJ/mol,而反应吸收能量为 2 99.85kJ/mol.次难进行的是ClONO2 经TS1到反应中间体M1,再经TS12而分解为ClNO +O2 的反应 .这个反应通道所需克服过渡态的能垒为 4 2 1.5 5kJ/mol,反应吸收能量为 15 7.98kJ/mol.从以上分析可知 ,和ClO +NO2 反应生成ClONO2 比较 ,ClONO2 具有较好的稳定性 .     

电源最大输出功率的条件及公式的应用

当外电路的电阻等于电源内电阻时,电源输出功率最大,应用这个结论,可以省去许多计算步骤.但实际应用时还要注意一些问题,下面从几个方面加以讨论.1 电源实际输出功率与最大输出功率的区别 这是两个不同的概念,一些学生往往会用Pm=(?)/4r计算电源输出最大功率,其实,(?)/4r只是电源输出功率的极限,电源一般不在该状态下工作.