Colour centres in powdered KI

Fine powder of KI was coloured in an electrodeless discharge. Due to quick bleaching of the F centres produced in this method, it was possible to prepare the samples that were almost free from the F centres. High concentration of the electron deficient centres could be produced, which were studied by measuring the diffused reflectance. A band at 354 nm is shown to be composed of two overlapping bands. Further, growth of a band appearing at 265 nm is studied. Bleaching characteristics of the samples are studied and it is shown that, similar to F centre bleaching, bleaching of these samples also proceeds in at least two steps. The difference between two components of the bleaching curves is quite marked. Further it is showed that the components are related to the presence of different absorption bands and appear at different stages of colouration.     

Adsorption of adamantanol isomers on graphitized thermal carbon black

The thermodynamic characteristics of adsorption of some adamantanol isomers on graphitized thermal carbon black were calculated and determined experimentally. The parameters of the potential function for the intermolecular interaction between hydroxyl oxygen and carbon of the graphite basis plane were determined for the first time. The adsorption properties of adamantanols are largely determined by electron density distribution in the adamantane cage, which are related to the cage effect.     

Polarizations on Abelian Varieties and Self-dual ℓ-adic Representations of Inertia Groups

It is well known that every finite subgroup of GL _d (Q ) is conjugate to a subgroup of GL _d (Z ). However, this does not remain true if we replace general linear groups by symplectic groups. We say that G is a group of inertia type of G is a finite group which has a normal Sylow-p-subgroup with cyclic quotient. We show that if >d+1, and G is a subgroup of Sp _2d (Q ) of inertia type, then G is conjugate in GL _2d (Q ) to a subgroup of Sp _2d (Z ). We give examples which show that the bound is sharp. We apply these results to construct, for every odd prime , isogeny classes of Abelian varieties all of whose polarizations have degree divisible by ². We prove similar results for Euler characteristic of invertible sheaves on Abelian varieties over fields of positive characteristic.     

数字闭环光纤陀螺频率特性分析与测试

系统的闭环带宽严重影响光纤陀螺在振动、急转弯等环境条件下的测试精度,闭环光纤陀螺的实际带宽高达几kHz,无法采用一般的角振动台进行全频带频率特性测试,因此,频率特性的分析与测试成为了闭环光纤陀螺研究的一项重要内容。针对这种需求,根据系统的结构框图及工作原理,建立了数字闭环光纤陀螺的动态模型,推导出了系统的传递函数;在此基础上对数字闭环光纤陀螺的频率特性进行了分析,指出了改善系统动态特性的方法;最后,利用数字闭环光纤陀螺的闭环工作原理,通过在反馈阶梯波上直接叠加激励信号,实现了光纤陀螺阶跃响应和频率响应的测试,得出了系统闭环带宽高达9kHz的结论。     

Resonant electromechanical vibrations of piezoelectric shells of revolution (review)

Scientific results from studies on the resonant electromechanical vibrations of piezoceramic thin-walled shells of revolution, their fragments, and segmented cylinders are analyzed, systematized, and generalized. Considerable attention is focused on experimental studies of resonant vibrations. It is shown that the modes in which deformation occurs inphase throughout the volume are of the highest intensity in all piezoceramic shell structures __________ Translated from Prikladnaya Mekhanika, Vol. 44, No. 4, pp. 3–34, April 2008.     

古尔班通古特沙漠生物土壤结皮反射光谱特征分析

通过对野外采样取得的新疆古尔班通古特沙漠中的生物土壤结皮、裸沙和干枯植被进行反射光谱测定,揭示出在干燥条件下各类地物的反射光谱特征。进一步对经过均匀喷洒0.5和1.0 mm水后的生物土壤结皮分别进行反射光谱测定,并对比分析了原始的和经水化实验后的生物土壤结皮光谱特征。依据生物土壤结皮的光谱特征,提出利用连续统去除技术估算生物土壤结皮覆盖度的方法,结果表明连续统去除光谱的负对数与生物土壤结皮盖度有很好的相关关系(r2=0.990 7)。     

任意截面光波导的模式计算

提出了一种计算近理想形状任意截面光波导模式特性的方法。首先运用微扰理论计算出光波导的电磁场分布,然后从麦克斯韦方程出发推导出一个计算光波导传播常数的公式并由此得出其色散曲线,该方法没有繁杂的计算过程。     

凹折射微透镜阵列的离子束刻蚀制作

利用光刻热熔成形工艺及离子束刻蚀制作 12 8× 12 8元凹微透镜阵列。所制硅及石英凹微透镜的典型基本图形分别为凹球冠形、凹柱形和矩顶凹面形。分析了在光致抗蚀剂柱凹微透镜图形制作过程中的膜系匹配特性 ,与制作该种微透镜有关的光掩模版的主要结构参数 ,以及光致抗蚀剂掩模工艺参数的控制依据等。探讨了在凹微透镜器件制作基础上利用成膜工艺开展平面折射微透镜器件制作的问题。采用扫描电子显微镜 (SEM)和表面轮廓仪测试了所制石英凹微透镜阵列的表面微结构形貌。给出了所制石英凹微透镜阵列远场光学特性的测试结果。     

桁架结构动力特性可靠性优化设计

对结构物理参数和几何尺寸同时具有随机性的桁架结构动力特性进行了分析,构建了以杆截面积为设计变量,结构重极小化为目标函数,满足基频和频率禁区可靠性约束的约束动力优化设计数学模型,并对其中关切频率的估定、两种频率约束的统一表示等予以讨论,利用复合形法求解,最后给出了两个算例。     

具有频率和振型概率约束的工程结构动力优化设计

对随机参数结构建立了具有频率、频率禁区和振型位置概率约束的结构动力优化设计数学模型;利用一次二阶矩法对概率约束进行了等价化处理,推导了频率、振型节点位置和可靠性指标对设计变量的灵敏度表达式;利用子空间迭代法和混合罚函数法求解,通过梁和板两个结构算例证明文中模型的合理性和求解方法的有效性。