On the basis of the results of emulational material model test of rock-bolt crane girder,the whole process of the failure of rock-bolt crane girder under crane wheel load was *** seems that the crane wheel load is sus...
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On the basis of the results of emulational material model test of rock-bolt crane girder,the whole process of the failure of rock-bolt crane girder under crane wheel load was *** seems that the crane wheel load is sustained mainly by the adhesive tensile force of vertical interface and the compression of inclined interface before the crack of ***,the adhesive tensile strength of rock-concrete interface should not be taken into account in the analysis of rock-bolt crane girder for the reliability in the long *** limit state of tensile bolts yield and the concrete or rock over the edge of compressive zone crush was proposed to be the ultimate limit state,on which three equilibrium equations were deduced for the design and analysis of rock-bolt crane girder. Moreover,the effect of release stress seems to be equivalent to prestressing a certain tension in the bolts of rock-bolt crane girder before crane ***,we proposed that release stress should not be considered in the analysis of rock-bolt crane girder since it is independent of the bearing capacity of rock-bolt crane girder in ultimate limit state.
The potential of metal matrix composites (MMCs) as new generation erosion and erosioncorrosion resistant materials is investigated. As a type of wear attack, erosion involves destructive impact of free-moving particle...
The potential of metal matrix composites (MMCs) as new generation erosion and erosioncorrosion resistant materials is investigated. As a type of wear attack, erosion involves destructive impact of free-moving particles on a solid. The high-strain-rate and hence adiabatic deformation conditions that the target surface experiences during erosion are often the reasons behind the poor correlation of erosion rate with static mechanical properties of the targets, imparting difficuties on erosion study. On the other hand, a good correlation exists between erosion rate and the thermophysical properties of the target. This, however, suggests limited possibilities of enhancing erosion resistance on a monolithic alloy. A literature study at the beginning elaborates the complex of erosion as a physical phenomenon, and lies the theoretical base for the experiment.
In the experiment, nickel-chromium superalloy- and heat resistant steel-based composites are manufactured through a powder metallurgy route. Ceramic particles are added at different volume fractions as the reinforcements. Efforts are made to optimise the powder mixing and powder consolidation procedures to ensure a homogeneous microstructure and full densification of the final composites. Two types of erosion tester are used in the study: a centrifugal erosion tester is for the erosion tests at room temperature, and a gas-blast erosion tester is for the erosion-oxidation tests at high temperature. With the gas-blast tester, both the temperature and oxygen concentration is controlled to simulate real application situations.
The discussion is focused on the tests under a 60° angle of impact. Optical and SEM (scanning electron microscopy) observations are carried out on the eroded surfaces to assess the damage pattern and general behaviour of the studying composites. Meanwhile, on cross-sectioned specimens the bonding and material dissolution at the matrix/reinforcement interfacial regions and the deformation situation
A radio access protocol, which can be applied to low earth orbit satellite and cellular internet access, is proposed by ZOHAR N and HANOCH L in their paper in 2001[1]. In their scheme, an access probability is compute...
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A radio access protocol, which can be applied to low earth orbit satellite and cellular internet access, is proposed by ZOHAR N and HANOCH L in their paper in 2001[1]. In their scheme, an access probability is computed by the central station, according to the load on shared channels. The focus in this paper is on the impact of load estimation error on the channel throughput, channel delay, and the equilibrium of the system. At the end of this paper, a conclusion is drawn that higher estimation makes the channel more efficient, time delay more short, and backlogged users less at the equilibrium point than lower estimation does.
Objective To study the value of 1.5T MRI in long-term follow-up of rat C6 glioma model and the efficacy of EGFR antisence RNA therapy in *** Forty-three male Wistar rats, weighing 150 to 200 g, were used for this stud...
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Objective To study the value of 1.5T MRI in long-term follow-up of rat C6 glioma model and the efficacy of EGFR antisence RNA therapy in *** Forty-three male Wistar rats, weighing 150 to 200 g, were used for this study. They were divided into four groups: group Ⅰ (7 normal rats); group Ⅱ (16 rats inoculated C6 cells in the right caudate nucleus); group Ⅲ (12 rats with the C6 gliomas treated with EGFR antisence RNA by in site injection); and group Ⅳ (8 rats inoculated C6 cells transfected with EGFR antisence RNA in the right caudate nucleus). Group Ⅰ was examined by plain and enhanced MR scanning. Group Ⅱ-Ⅳ were followed up by plain and enhanced MR scanning and were sacrificed in variable time points for pathological *** Cerebral hemispheres of normal rat were shown clearly on the MR image. The tumor could be seen about 1 week after inoculation. According to the findings on the follow-up MR scan, we could observe growth of the tumor or its regression after treatment. The tumor growth was significantly inhibited in group Ⅲ and group Ⅳ as compared to those in group Ⅱ.Conclusion The growth of the rat C6 glioma model and its change after treatment could be shown clearly in 1.5T MR imaging; EGFR antisence RNA significantly inhibited the growth of glioma in vivo.
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