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.     

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。     

改善准分子激光光强分布的一种方法

介绍了一种改善准分子激光输出光束光强均匀性的新方法，给出了实验结果和简要的分析。     

轴向柱塞泵配流副油膜的实验研究

本文介绍了对６３ＣＹ１４－ＩＢ型轴向柱塞泵配流副油膜的实验研究结果。该研究结果为改进该泵配流副的性能提供了依据。     

无溢流管多层流化床换热器的热态模型研究

本文对无溢流管多层流化床换热器进行了热态模型实验研究，得出了气－固两相间的界膜换热系数曲线，所得结论可供参考。     

A singular loop transformation framework based on non-singular matrices

In this paper, we discuss a loop transformation framework that is based on integer non-singular matrices. The transformations included in this framework are called Λ-transformations and include permutation, skewing and reversal, as well as a transformation calledloop scaling. This framework is more general than existing ones; however, it is also more difficult to generate code in our framework. This paper shows how integer lattice theory can be used to generate efficient code. An added advantage of our framework over existing ones is that there is a simple completion algorithm which, given a partial transformation matrix, produces a full transformation matrix that satisfies all dependences. This completion procedure has applications in parallelization and in the generation of code for NUMA machines. This work was supported by the Cornell Theory Center, NSF Presidential Young Investigator award #CCR-8958543. by NSF Grant #CCR-9008526, and by a grant from the Hewlett-Packard Company.     

后工业景观的理性化设计

后工业景观必须借助于其后工业性才能保持特色,保存历史遗留下来的记忆,为人们的生活服务。文章探讨了产业结构转型后的工业废弃地在景观设计中面临的问题,从场地的前期整饬和对工业遗存在景观设计中的取舍两个方面进行了研究。