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131.
G. D. Petrov E. Ya. Uzhenkov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1976,10(2):131-138
| 1. | The use of unheated coarse aggregates in concrete is permissible with respect to heat-balance conditions in the majority of cases, even in regions of the Far North. |
| 2. | The use of unheated coarse aggregates under construction conditions is possible if there is no danger of their freezing together with loss of granular properties. These requirements are met to the maximum degree: a) in regions with a limited amount of precipitation, stable air temperatures during the winter, and minimum number of transitions of the air temperature through 0°; b) at construction sites with local quarries and crushing-grading and concrete plants operating in close proximity with maximally limited intermediate stockpiles of aggregates. |
| 3. | The use of unheated coarse aggregates under construction conditions should not be allowed if there is the danger of freezing together of the aggregates with their loss of granular properties. It is necessary to provide for the possibility of thawing coarse aggregates by a simplified one-stage scheme with heating to 3–5°C. |
| 4. | In the case where there is the danger of freezing together of only the fine sandy gravel (rubble), these fractions can be thawed and used with the other fractions of coarse aggregate without heat treatment. |
| 5. | During curing of the concrete the danger of an ice surfacing forming on the outer surfaces of grains up to 120 mm in size is eliminated if a positive temperature of the concrete mix is provided at the outlet to the mixer (mean volume temperature) and when arriving at the block for placement. |
| 6. | The qualitative characteristics of the coarse-aggregate concrete with grain sizes to 120 mm, natural content to 1.5%, and temperature to minus 25–30°C with heating of the sand and water to temperatures determined by the conditions of the overall heat balance are not inferior to those for concrete prepared according to the existing winter technology with heat treatment of all components of the concrete mix except the cement. |
| 7. | When using unheated coarse aggregates, heating of the sand in fluidized-bed and air-flow devices or air-spout dryers can be considered the most promising methods of heat treatment of the sand, providing it with a stable temperature and water content. |
132.
V. I. Ivchenko M. I. Lesnaya V. F. Nemchenko T. Ya. Kosolapova 《Powder Metallurgy and Metal Ceramics》1976,15(5):367-369
| 1. | A study was made of the microhardness and the temperature dependence of the thermal conductivity, electrical resistivity, thermo-emf, and coefficients of thermal expansion of two ternary compounds in the system Ti-Al-C. |
| 2. | It was established that the conductivity of these compounds has a metallic character. |
| 3. | From the microhardness and coefficient of thermal expansion values obtained it can be concluded that the atomic linkage forces in these compounds grow in the order Ti2AlC <>3AlC < tic.="> |
133.
一种高效的视图维护算法 总被引：7，自引：0，他引：7
通过选择性算法将增量式视图维护和视图自维护有效地融合在一起．同时它还利用相关性算法对不相关更新进行过滤，可以有效地降低消息总数和数据的通信量，从而大大提高视图维护的效率，具有现实的应用意义． 相似文献
134.
135.
The paper discusses mode locking use in pulsed lasers for precision measurement of large lengths. 相似文献
136.
Belomyttsev S. Ya. Grishkov A. A. Korovin S. D. Ryzhov V. V. 《Technical Physics Letters》2004,30(12):1060-1063
Technical Physics Letters - A solution corresponding to a thin annular electron beam in a homogeneous drift tube featuring a uniformly moving virtual cathode (VC) has been obtained. The dependence... 相似文献
137.
Quasiperiodic phases (quasicrystals) with symmetries forbidden by classic crystallography have been observed in systems of aluminum with transition metals. In binary systems, these phases are metastable; they were obtained for the first time by rapid solidification of melts. We consider the formation of the quasicrystals and we refine the phase diagrams for binary systems A – 3d-M (from V to Ni) in which quasicrystals have been observed. 相似文献
138.
G. Ya. Bezlyud'ko V. F. Muzhitskii V. B. Remezov 《Russian Journal of Nondestructive Testing》2003,39(4):289-296
A series of instruments (structuroscopes) assigned for determining various characteristics of materials and products on the basis of the coercive force is described. Main technical characteristics of three types of the instruments are given. The last and most perfect modification is KRM-Ts-K3 instrument. It is provided with a self-contained power supply and has a wide measurement range. It has an internal memory for 4096 measurements and can be connected to a personal computer. Specially designed program software makes it possible automatically to construct graphs. Examples of graphical representation of the measurement data are demonstrated for two- and three-dimensional reproduction of the results. 相似文献
139.
城乡二元结构体制对教育产生了深刻的影响,尤其制约着农村教育的发展,优先发展教育,就必须优先发展教师教育,是实现城乡统筹发展背景下重庆市基础教育均衡发展的基本思路和策略选择.基于重庆市中小学教师队伍存在的问题,建议从完善政策保障机制、资源的优化配置、完善师资队伍培训机制、创新教师培养模式等方面来优化重庆市中小学教师队伍. 相似文献
140.
介绍了中厚板自动化超声波探伤的主要技术参数及应用,以及如何对铜板内部缺陷进行定位和定量,进而进行准确的判定,采用面积分割法计算对于掌握缺陷的形状、分布,有着重要的意义。 相似文献