Effects of water-soluble

The effect of the amount of a water-soluble, lactose, on cephalexin (CEX) release from bioactive bone cement consisting of bisphenol--glycidyl methacrylate (bis-GMA), triethylene-glycol dimethacrylate (TEGDMA) resin and apatite- and wollastonite-containing glass-ceramic (A–W GC) powder was investigated. A–W GC powder containing 5% CEX and lactose powders hardened within 5 min after mixing with bis-GMA/TEGDMA resin, and furthermore its compressive strength was expected to be higher than that of polymethylmethacrylate cement. In vitro CEX release from bioactive bone cement pellets in a simulated body fluid at pH 7.25 and 37°C continued for more than 2 wk. The drug-release rate increased with increasing amount of lactose powder in the mixture. CEX release profiles followed the Higuchi equation in the initial stage, but not in later stages. As hydroxyapatite was precipitated out on the cement surface, the CEX release rate decreased. The micropore distribution of the cements measured by mercury porosimetry also supported the variation in drug release due to cement porosity being mainly a result of the dissolution of lactose in the cements. These results suggest that the rate of CEX release from bioactive bone cement could be controlled by varying the amount of lactose in the cement system. © 1999 Kluwer Academic Publishers     

刺激空间特征和反应位置对线索效应模式的影响

以具有不同空间特征的十字号为实验材料,采用反应线索范式,旨在探讨刺激空间特征和反应位置对线索效应模式的影响.结果表明：①左右特征突显可以获得最优的反应准备绩效,而内外特征突显增强则导致最差的反应准备绩效;②不同线索效应间的差别主要出现在中间两个反应位置上,尤以突显特征增强时明显.结论：左右特征突显是线索反应任务中较为理想的空间刺激安排方式;与外侧两个反应位置相比,线索对于中间两个反应位置的提示作用更大.     

Effects of microgravity on microcirculation

The blood behaviour in human circulatory system observed during space flights reveals that the microgravity environment reduces the flow rate and increases the haematocrit compared with the situation on the earth surface. The present study gives a theoretical analysis of the above phenomena by considering a two layer Newtonian model for blood flow in capillaries. The effect of gravity on plasma layer as well as on the blood viscosity is taken into account for calculating the percentage change in flow rate of blood. The corresponding apparent viscosities on the earth surface and in space are estimated. The results are analyzed and presented graphically. The findings agree reasonably well with the data observed in spaceflight experiments.     

金属纳米微粒的尺寸效应

在假定金属纳米微粒是球形的基础上，综述了金属纳米微粒的基本表征量、结合能、晶格参数、空位形成能和空位体积的尺寸效应，提出一个形状因子来描述非球形纳米微粒的形状对性能的影响，并对以后的研究进行了展望。     

脱水过程对细胞骨架的影响

外界的剧烈变化会对细胞内部产生一定的影响,本文通过考马斯亮蓝染色法研究细胞骨架中的微丝在脱水过程中的形态变化。通过图像处理的方法对骨架图像的灰度峰度进行分析处理,发现随着脱水过程的进行,灰度图像出现弥散性下降,骨架形态更为疏松并伴随解聚等一系列形态变化。对图像的特征参数进行定量计算后,结果表明:持续真空环境下骨架的最终相对变化率为32. 7%,持续低温环境下的最终相对变化率为59%。对细胞变形度研究结果表明,脱水过程会对细胞骨架产生较为显著的影响。     

Volume Effects of Daily Hemodialysis

Daily hemodialysis appears to be well tolerated, with hypotension rarely complicating such therapy, a finding that is the subject of this review. When daily hemodialysis utilizes a shorter treatment time, this may limit the intradialytic reduction in plasma volume. This reduction is a function of treatment time, ultrafiltration rate (UFR), and plasma refilling rate (PRR). However, daily therapy may be associated with a higher UFR and lower PRR, both of which may accentuate the fall in plasma volume. The reduced frequency of intradialytic hypotension may, in part, be related to other aspects of such therapy, such as the smaller oscillations and decreased dialytic flux of hemodynamically active solutes.     

Effects of relaxation in levitating superconductors

The effect of the magnetic flux creep on the levitation stability of high-temperature superconductors was studied. It was shown experimentally that under a unipolar magnetization the levitation force decreased at a logarithmic velocity characteristic of the creep process. If the current structure was bi- or multi-polar one, which was formed in a sample exposed to a reversing external magnetic field, the force remained unchanged during a certain period of time. The theory of relaxation of magnetization and force for a partial and full penetration of the critical state was considered. It was shown that relaxation decelerated sharply if the region with a current producing the main magnetization was far from the superconductor surface. A concept of an open and internal magnetic relaxation was introduced. The time of the internal relaxation for different reverse depths was estimated. The calculated values approached the experimental values of the levitation stabilization time.     

烟囱爆破拆除的地震效应分析

使用ＮＣＳＣ５３００测震仪测量３０ｍ钢筋混凝土烟囱定向拆除爆破的振动结果，分析高型薄壁筒状结构物爆破拆除引起的爆破振动和对地面的冲击作用，得出地震效应的一般性结论。     

爆破地震对结构的影响

本文从爆破振速和爆震频率两方面介绍了爆破地震对结构的影响，非爆破因素对结构的影响，以及围绕这些所进行的各项研究和实验。     

睡眠剥夺对警觉能力的影响

为探讨不同睡眠剥夺（sleep deprivation，SD）时间对于警觉性的影响，将24名正常青年男性分为SD21h组、SD45h组、SD69h组，每组8名，主要应用三个字母（C、G、N）的划销测验来测查不同SD条件下的警觉能力。测试时间分别为每天的7：00、10：00、13：00、16：00、19：00、22：00、l：00、4：00，采用组间比较和自身前后比较。结果：sD后，完成时间、总击中数、假阳性数和倒数第二分钟击中数表现出成绩显著下降，并同SD时间有关；完成时间和总击中数表现出生物节律的作用；倒数第二分钟击中数同SD相关系数最高，为非常好地评定警觉性的指标。结论：SD后警觉水平下降，并且同SD时间长短有关；SD时，字母划销测验是非常好的测查警觉性的测验。     

添加纳米颗粒对复合镀层性能的影响

纳米材料具有特殊的力学、热学、光学、电学等性质,当把纳米颗粒加入到电镀溶液中时,制备出的纳米复合镀层比普通镀层具有更优良的各种性能.论述了纳米材料用于复合镀后对镀层的强度、抗高温氧化性、耐摩擦性、光学性能、电学性能、磁学性能、抗腐蚀性、电催化性、自润滑性等各方面性能的改善和提高,并展望了纳米材料在复合电镀中的应用前景.     

纳米产品对玉米生长发育的影响

在砂培和盆栽试验中用几种不同的纳米技术产品浸种和处理水浇灌,研究了其对玉米发芽和生长发育的影响。结果表明,纳米材料可提高玉米种子的吸水能力（种子吸水量较对照提高0．92％～2．33％）;提高种子发芽势和发芽率,降低霉变率;增加植株生物量、根系量、根长和根表面积;促进玉米对NPK,特别是P的吸收,植株P的含量和NPK的吸收量明显提高。用纳米材料浸种同时用处理水灌溉的效果优于只浸种的,说明处理水对玉米的生长有促进作用。     

Effects of atoms on brittle fracture

This article aims to answer two related sets of questions. First: in principle, how large an effect can structure at the atomic scale have upon the fracture of two macroscopically identical samples? The answer to this question is that the effects can be very large. Perfectly sharp cracks can be pinned and stationary under loading conditions that put them far beyond the Griffith point. Crack paths need not obey the rule K _II=0. Crack speeds can vary from zero to the Rayleigh wave speed under identical loading conditions but depending upon microscopic rules. These conclusions are obtained from simple solvable models, and from techniques that make it possible to extrapolate reliably from small numerical calculations to the macroscopic limit. These techniques are described in some detail. Second: in practice, should any of these effects be visible in real laboratory samples? The answer to this second question is less clear. The qualitative phenomena exhibited by simple models are observed routinely in the fracture of brittle crystals. However, the correspondence between computations in perfect two-dimensional numerical samples at zero temperature and imperfect three-dimensional laboratory specimens at nonzero temperature is not simple. This paper reports on computations involving nonzero temperature, and irregular crack motion that indicate both strengths and weaknesses of two-dimensional microscopic modeling.     

The Effects of Leadership on Quality

Abstract:

Research examining quality management has focused primarily on manufacturing organizations with specific attention directed toward organizational employees. Many in the field of quality believe that management is key for a successful quality program, yet the effects of specific leadership styles on quality performance have not been determined. In this study, leadership styles within transformational, transactional and non-transactional classifications are evaluated relative to the organization's performance based on the criteria from the Baldrige Quality Award. Results indicate that leadership does have an affect on quality, and certain transformational and transactional styles are more effective.