Input saturation and global stabilization of nonlinear systems viastate and output feedback

For multi-input multi-output nonlinear systems whose free dynamics are Lyapunov stable, the author shows how the problem of global stabilization via dynamic output feedback can be solved by using the technique of input saturation. The power of this technique is also illustrated by solving the problem of global stabilization via bounded state feedback for affine nonlinear systems with stable unforced dynamics. Analogous results are established for discrete-time nonlinear systems     

SiH4＋CH4激光等离子体动力学时空特性

采用时间，空间分辨的等离子体光辐射诊断技术，研究了脉冲ＴＥＡＣＯ２激光诱发ＳｉＨ４＋ＣＨ４击穿产生的等离子体膨胀过程，得到不同空间位置，不同实验条件下等离子体发光的时间特性，证明了ＳｉＨ４＋ＣＨ４气体击穿产生爆燃波而后诱发激波是等离子体中基本宏观动力学过程，并在实验上分析了激波对等离体内化学反应的影响，为激光等离子体合成ＳｉＣ粉末微观反应动力学过程的研究提供了参考数据。     

单电子晶体管电导振荡及其解释

文中概述了单电子晶体管电导振荡的特点并进行了理论解释，进而讨论了介观电容及电容谱的概念。     

Neuronal units linked to microvascular modules in cerebral cortex: response elements for imaging the brain

How neuronal activity changes cerebral blood flow is of biological and practical importance. The rodent whisker-barrel system has special merits as a model for studies of changes in local cerebral blood flow (LCBF). Stimulus-evoked changes in neural firing and 'intrinsic signals' recorded through a cranial window were used to define regions of interest for repeated flow measurements. Whisker-activated changes in flow were measured with intravascular markers at the pia. LCBF changes were always prompt and localized over the appropriate barrel. Stimulus-related changes in parenchymal flow monitored continuously with H2 electrodes recorded short latency flow changes initiated in middle cortical layers. Activation that increased flow to particular barrels often led to reduced flow to adjacent cortex. Dye was injected into single penetrating arterioles from the pia of the fixed brain and injected into arterioles in slices of cortex where barrels were evident without stains. Arteriolar and venular domains at the surface were not directly related to underlying barrels. Capillary tufts in layer IV were mainly coincident with barrels. The matching between a capillary plexus (a vascular module) and a barrel (a functional neuronal unit) is a spatial organization of neurons and blood vessels that optimizes local interactions between the two. The paths of communication probably include: neurons to neurons, neurons to glia, neurons to vessels, glia to vessels, vessels to vessels and vessels to brain. Matching a functional grouping of neurons with a vascular module is an elegant means of reducing the risk of embarrassment for energy-expensive neuronal activity (ion pumping) while minimizing energy spent for delivery of the energy (cardiac output). For imaging studies this organization sets biological limits to spatial, temporal and magnitude resolution. Reduced flow to nearby inactive cortex enhances local differences.     

折反光学系统最佳红外像面位置的研究

较深入地研究了折反光学系统的红外像面,为确定实际的红外像面提出了一个新方法—计算从可见光边缘无色的弥散圆到红外最佳像面的距离。实践证明,这是确定这类光学系统最佳像面的一个方便、可靠的方法。     

菱镁复合装饰板质量保证措施

分析了菱镁复合装饰板起霜，翘曲等原因，并论述了原材料，配合比、复合外加剂和生产工艺的影响，提出了一套有效的质量保证措施。     

两种具有电双稳态的全有机络合物

首次发现两种在室温下即具有电双稳态的全有机（有机-有机）络合物，分别称为MCA＋TCNQ和BBDN＋TCNQ。它们可在真空中制备成薄膜，在数伏电压的作用下，从高电阻至低电阻的跃迁时间小于100ns，因此可作为一次写入的存储器材料。根据我国目前最小刻线宽度的水平，可望在1．6cm2的SiO2平面上做出64Mb的存储器。     

可调谐的双波长钛宝石激光器

一台可调谐钛宝石激光器两个波长同时运转,在数ns以内同步,相对波长差最大可达55nm。观测到明显的两种波长激光的竞争和关联。由BBO实现了两波的和频与倍频。     

Oxide and interface characteristics of oxidized silicon oxynitride ceramics – an investigation by electron microscopy

Hot-isostatically pressed silicon oxynitride (Si2N2O) ceramics free from sintering aids were oxidized in 1 atm dry oxygen at 1100 and 1300°C. The structural and chemical characteristics of the oxide and the nature of the oxide–Si2N2O interface were determined using cross-sectional transmission electron microscopy in conjunction with small-probe energy dispersive X-ray analysis and selected-area electron diffraction. Oxidation of Si2N2O resulted in the formation of amorphous SiO2. The oxide–Si2N2O interface was chemically abrupt. The interface was very flat when parallel to low-index, high atomic density Si2N2O crystal planes but became notably undulated if oriented to high index, low atomic density planes. About 6 vol% residual SiO2 phase was present in the bulk of the Si2N2O ceramics. Current results have provided an important baseline for the understanding of the oxidation behaviour of Si2N2O. © 1998 Kluwer Academic Publishers