Spectroscopic and laser properties of Nd~(3 ) ions in LaMgAl_(11)O_(19) crystals

The spectroscopic properties, optic quality and thermal lensing effect of Nd~(3 ) ions in LaMgAl_(11)O_(19)(LNA) crystals are investigated and the dependence of the laser characteristics on above properties are discussed.     

中国地震活动性的研究

根据中国新的地震目录数据库提供的自公元前780年至1990年5级以上强震的分布,讨论了东北、华北、华南、台湾、青藏高原、川滇及新疆地区的地震活动分区特征,以及本世纪7级以上强震的空间分布、震源深度分布、震源机制及应力场等,并给出了大陆岩石圈板内地震活动的若干特征。     

考虑各向异性的土工结构物动力分析

本文首先用共振柱研究小应变动剪切模量的各向异性问题,然后阐述了在土工结构动力分析中如何考虑土动力变形特性的各向异性,最后给出了考虑土动力变形特性各向异性动力分析的实例计算结果,并与通常假定土动力变形特性为各向同性的动力分析的结果进行比较.计算结果表明:对于具有很强各向异性的土工结构物和地基,当需要考虑垂直向振动时目前所用把土动力变形特性假定成各向同性方法得到的结果是偏于不安全的.     

浙江省海岛土地资源开发利用探讨

浙江省是全国岛屿最多的省份，海岛为全省实现“海洋经济大省”起着重要作用。本文在分析浙江省海岛土地利用现状及其特点的基础上，指出开发利用中存在的主要问题，提出了合理开发利用的战略对策。     

软件系统设计中的模块化思想和技术

本文回顾了设计大型数据处理系统中广泛应用的结构化设计(SD)方法、结构化分析(SA)及结构化程序设计(SP),阐明控制问题复杂性的抽象和分解思想、模块特性、划分模块的原则和评价模块质量标准及模块独立性概念。     

Thermodynamic characteristics of the activity of selected chromatographic sorbents

Summary The possibility of comparing various chromatographic sorbents in respect of their activity is discussed utilizing a simple thermodynamic approach presented earlier.     

四斜A/D转换系统动态问题的研究

在高准确度和高分辨力的四斜 A/D 转换中,只注意系统部件的静态特性已远远不能满足要求。本文提出并分析了四斜 A/D 转换系统的动态问题。把这一分析用于 DO-13 DVM 中的内控逻辑和积分器--第一检零器系统获得了成功。     

Characterization of proton NMR relaxation times in normal and pathological tissues by correlation with other tissue parameters

To help understand which tissue parameters best account for the water proton NMR relaxation times, the longitudinal relaxation time (T₂), the transverse relaxation time (T₂), and the water content of 16 tissues from normal adult rats were measured at 10.7 MHz and 29°C. Regression analyses between the above and other tissue parameters were performed. These other tissue parameters included: the amounts of various organic and inorganic components, protein synthetic rate, oxygen consumption rate, and morphological composition. In addition, the differences in T₁, T₂, and water content values between normal liver and malignant tumor (Morris #7777 a transplantable hepatoma) were studied to help understand how a disease state can be detected and characterized by NMR spectroscopy. The results of this study and information from the literature allow the following generalizations to be made about tissue T₁ and T₂ values: (1) Each normal tissue has rather consistent and characteristic T₁ and T₂ relaxation times which are always shorter than the T₁ and T₂ of bulk water; (2) tissues with higher water content tend to have longer T₁ relaxation times; (3) tissue T₂ values are not, however, as well correlated with water content as T₁ values; (4) tissues with shorter T₁ values have higher calculated hydration fractions, greater amounts of rough endoplasmic reticulum, and a greater rate of protein synthetic activity; (5) tissues with higher lipid content, associated with intracellular non-membrane bounded lipid droplets, tend to have longer T₂ values; (6) tissues with greater overall surface area, whether in the form of cellular membranes or intracellular or extracellular fibrillar macromolecules, tend to have shorter T₂ values; (7) the differences between T₁ and T₂ values between tumor and normal tissues correlated with differences in the volume fraction (amounts) of extracellular fluid volumes and in the amounts of membrane and fibrillar surface area in the cells. The above generalizations should be useful in predicting T₁ and T₂ changes associated with specific tissue pathologies.     

Switching characteristics of silver-silicon monoxide superlattices

Layer structures of successive silver and silicon monoxide layer pairs were made using evaporating techniques. Small angle X-ray diffraction and multiple reflection interferometric techniques have been used to establish the identity periods of the samples. these samples were found to have switching characteristics. Slow and fast switching was observed and the application of voltage would induce switching into higher as well as into lower resistance states. Sequential switching through multiple resistance states has also been observed.