In order to simplify the nonlinear analysis of reinforced concrete, a new study on concrete strength criterion under tension condition is made, and more simple and accurate practical calculation equations are put forward. The results from the equations agree well with the experimental data.
To reduce the cost of HDPE optical cable sheath, we selected HDPE as matrix materials, inorganic nanometer particles (CaCO3, SiO2) as modifier, prepared the modified HDPE optical cable sheath by mechanical blending method. The combination of CaCO3 particles with HDPE matrix was improved by titanate doped, which was able to facilitate the homogeneous dispersion of CaCO3 particles inside HDPE. To modify the optical cable sheath and reduce the product cost, the disparity of the inorganic nano-particle was analyzed, and the ratio of raw material and mixing technology were also improved. The experimental results indicated that: the sheathing compound with insulating characteristic as well as all technical indexes that reached its national standard, especially the toughening effect of the CaCO3, could be produced when CaCO3 content reached 7.5% and the volume resistivity was 104 times higher than the national standard. The mechanical modification of CaCO3 was better than SiO2.
This article introduces interval factors involved in material mechanics, and it also has many problems of interval parameters. Compressive rod stability design will be taken as an example to discuss interval analysis processing method; it explains not only the necessity for material mechanics and engineering design to lead into the interval analysis method, but also the specific application of it.
As carbon fiber reinforced silicon carbide composites combine the excellent mechanical properties of carbon fiber with good oxidation resistance of silicon carbide, considering material properties and economic cost, so much attention has been focused on short fiber reinforced ceramic matrix. but short carbon fiber is difficult to uniformly dispersed in the silicon carbide matrix, so how to disperse short carbon fibers in the matrix has become the key to prepare composite materials. In this article, through three processing methods to improve the dispersion, the three method are surface treatment of short carbon fibers, changing the mixed material ball milling time and adding a certain amount of SiC whisker. Results showed that the three processing methods all can improve the dispersion of short carbon fibers in silicon carbide matrix, but the dispersion effect also are different and the mechanism are different.the composites with better dispersion can achieved when carbon fibers which oxidized in concentrated nitric acid (68%) for 90minutes,and ball milling time was 48h and the concentration of SiC whisker was 5%.
Optical fiber preform is the core in the industry of optical fiber manufacturing, and vapor deposition is used in general internationally of which the raw material is expensive and the craft is complex. To reduce the cost of optical fiber,we selected tetraethoxysilane (TEOS) and H2O as raw material, ethanol as solvent, hydrochloric acid (HCl) and ammonia water as catalyst,in the condition of using different anti-cracking agent, including formamide (CH3NO), oxalic acid (C2H2O4), polyethyleneglycol 2000 (HO(C2H4O)nH), N, N-dimethyl formamide(C3H7NO) and glycerol(C3H8O3), to prepare SiO2 dry gel by sol-gel method in this paper. This paper mainly researched on the effect of anti-cracking agent on the cracking property of SiO2 dry gel. The XRD analysis indicated that the samples’ microstructures were amorphous. All kinds of anti-cracking agent were worked, but the effect on anti-cracking was different,and the dry gel which was added C3HNO was smooth and optimum, which were confirmed by the results of SEM. The analysis of the transmittance showed that the transmittance of dry gel with C3H8O3 was more than 92 percent.
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