Destruction of polymer growth substrates for cell cultures in two-photon microscopy

The choice of the growth substrate for cell cultures used in fluorescence microscopy is guided by several factors including the type of cells studied and the type of microscopy used. Usually, cells can be cultured on either polymer or glass substrates. One type of polymer, termed Aclar, presents several attractive features: the adhesive properties are better than those of glass, the optical properties are comparable to those of glass, it is biochemically inert, unbreakable, flexible and has a high surface tension, convenient for seeding cells on the cover slip. However, here we show that when imaging with two-photon microscopy, which is based on a femtosecond pulsed laser source, local damage of the Aclar substrate occurs, starting at an average intensity of 10⁵ W cm⁻² at the focal point and for exposure times insufficient to cause cell damage. This leads to the appearance of gas bubbles on cultures plated on Aclar cover slips, which perturb the imaging. By contrast, this phenomenon does not occur on borosilicate cover slips, probably because of their different physical (thermal conductivity, absorbance, melting point) and material homogeneity properties. Thus, for cell culture applications using pulsed lasers with high intensities, the use of glass is preferable to Aclar. The results also reveal that substrates can be more susceptible to thermal damage than the cells themselves.     

搅拌机轴端浮动油封装置设计制造研讨

介绍了浮动油封的功能，研究了浮动油封的工作原理，分析了浮动油封实现密封功效的条件和浮动油封装置的设计程序，探讨了转环毂和滑环毂的主要工艺要求，从而积累搅拌机轴端浮动油封装置设计经验。     

Rutschblock-scale snowpack stability derived from multiple quality-controlled SnowMicroPen measurements

Stability prediction from SnowMicroPen (SMP) profiles would support avalanche forecasting operations, since objective stability information could be gathered more quickly than with standard tests, thereby allowing sampling at higher resolution and over larger spatial scales. Previous studies have related the snow properties derived from the SMP to observed snow properties at Rutschblock (RB) and compression test failure planes. The goals of this study are to show to what extent snowpack stability for artificial triggering, based on RB, can be derived from SMP measurements and how multiple measurements at the RB scale improve the results. Measurements at 36 different sites were used for the development of a classification scheme. Each site included a RB test, a manual profile, and 6 to 10 adjacent SMP measurements, for a total of 262 SMP profiles. A recently improved SMP theory was applied to estimate the micro-structural and mechanical properties of manually defined weak layers and slab layers. SMP signal quality control and different noise treatment methods were taken into consideration in the analysis. The best and most robust predictor of RB stability was the weak layer micro-scale strength. In combination with the SMP-estimated mean density of the slab layer, the total accuracy of predicting RB stability classes was 85% over the entire dataset, and 88% when signals with obvious signal dampening (11% of the dataset) were removed. The total accuracy increased when multiple SMP measurements at the RB scale were used to calculate the mean weak layer strength, when compared to using just one SMP measurement at a site. The analysis was robust to trends and offsets in the absolute SMP force, which was a frequent signal error. However, it was sensitive to dampened or disturbed SMP force micro variance. The sensitivity analysis also showed that the best predictor of instability, the weak layer micro-scale strength, was robust to the choice of SMP signal noise removal method.     

水淹水导轴承的原因分析与处理

对某水电站水淹水导轴承原因进行分析并提出解决处理方案和应采取的防范措施,对机组顶盖排水泵进行改造。自改造投产以来,再没发生过水淹水导轴承的事故,为机组的安全稳定运行提供有力保障。     

多维随机向量典型相关系数与弱线性相关性

介绍了两个多维随机向量典型相关系数、线性相关、弱线性相关等概念，以及典型相关系数与线性相关性的关系。在此基础上，讨论了为1的典型相关系数的个数为零与弱线性相关的关系。     

铁水沟沟闸防尘罩的设计与材料选择

设计制作了一种可单人移动的防尘罩,拨闸时可起到明显的防烟尘作用。该防尘罩重量为41.2 kg,最大安全载荷4 500 N,工作时外表面温度50℃左右,起到了较好的防尘隔热作用。介绍了该防尘罩的设计思路与制作过程中材料的选择以及工艺的优化。     

多棱盒形盖注塑模设计

介绍了多棱盒形盖注塑模的设计过程。重点介绍了分型面的设计、浇注系统零部件的设计。采用一模多腔结构,有利于自动化和批量化生产;采用侧浇口浇注系统,保障了塑料件的表面质量。此外,在模具复杂且易磨损的部位,采用了镶拼式零部件,在降低模具加工难度的同时,也提高了模具的寿命。     

山区高速公路隧道偏压浅埋洞口段施工技术探讨

针对山区高速公路隧道偏压浅埋洞口段施工,从施工原则、施工加固方案等方面进行系统阐述,为类似工程提供参考。     

THE CATEGORY THEORY OF TIME SYSTEMS

In this paper we show a categorical treatment of general time systems using the categorization method presented in our previous paper. Various concepts about general time systems are categorized in the unified framework. Some category theoretical tools for the investigation of such time systems are presented. Using those tools some basic properties of time systems are explored in our framework. In particular, a conceptual equivalence between the causality and the state space representability is proved in the categorical terms. These results show that our method can be a universal tool for a categorization and a categorical treatment of mathematically defined general systems.     

平面真空玻璃作箱式太阳灶透明盖板的实验研究

介绍了用窄缝高真空平面玻璃作普通工太阳灶的透明盖板，对箱式太阳灶的集热性能进行了实验研究的结果，并与用普通双层玻璃作盖板的箱式太阳灶进行了对比，发现用平面真空玻璃作盖板能够显著改善箱式太阳灶的性能。