Advanced Materials Research Vols. 399-401

Abstract: In order to study actual work performance of the external pre-stressed combination box girder with corrugated steel webs, and to analyse the integral stress of box girder influenced by the corrugated steel webs, and understand the construction of the type combination box girder, this document studied the model test of the external pre-stressed combination box girder with corrugated steel webs, tried to find out the bending rule for the combination box girder and the model test result influenced by the different connections style. And the model test result was based on the assumption of “flat section” and within the elastic range, when the concentrated loads loaded on the box girder, the deflection was linear with the loads, and the corrugated slab stress was zero, which indicated the slab can not bended and the moment was supported by the top and the bottom slab, and the corrugated slab only supported the shear, and the shear lag effect only influenced local area. The conclusion of the model test will provide the reference for the bending capacity research, design and construction.

Abstract: Photoelectric film is an important information functional material transforming optical signals into electric signals. Composite dielectric photoelectric films formed by burying metal nanoparticles in semiconductors are different from traditional photoelectric films and semiconductor films, which will show special performance and may be applied in high-speed optical and optoelectronic devices. time response of photoelectrons to emission increases with the increase in the energy of incident photons; when the surface barrier decreases, response time increases; The smaller the film thickness is, the faster the time response of photoelectrons will be.

Abstract: As the interaction mechanism between disc-cutter and wall rock is the key to the TBM performance of breaking-rock, many exports who come from different countries have so far made a great deal of studies, tests, analyses and modeling works and many models of mechanism of rock-fragmentation were achieved. Some new corrections are made constantly according to the experiences accumulated from engineering practice. This paper summarizes the works of the scholars and some analyses and comparisons are made. Based on the CSM and NTNU, a new model is presented to takes into account some ingredients, which would influence the efficiency for TBM to break wall rock. To enhance the level of design, manufacture and operation of TBM, the databases for rock attributes, main parameters of TBM and excavating parameters should be found.

Abstract: Modified neoprene adhesive dedicated to bonding UHMWPE and 45# steel was prepared. Thermal analysis with TG-DTG curve was determined and its thermal decomposition kinetics was studied. The result show that the thermal degradation process of CR/MMA/CPE/MgO adhesive is a three-step reaction and the its thermal degradation starting temperature is 200°C and complete decomposition temperature is 570°C. The first mass loss stage is 0.6 order chemical reaction and its average activation energy E is 19.21kJ/mol and pre-exponential factor A is 3.68×10². The second mass loss stage is 3 order chemical reaction and its average activation energy E is 82.14kJ/mol and its pre-exponential factor A is 1.52×10⁸. The third mass loss stage is 3 order chemical reaction and its average activation energy E is 55.07kJ/mol and pre-exponential factor A is 1.33×10⁵.

Abstract: The morphology and structural evolution of nano-SiO₂ powers obtained by pressuring samples and sintering in muffle at different temperatures were studied by X-ray diffraction (XRD) and atomic force microscope (AFM). The experimental results show that the particle sizes of nano-SiO₂ increase with temperature rising, and it meets the physical mechanism of particle growth.

Abstract: Along with the improvement of surface defect and decarburizing problem, the non-metallic inclusion becomes one of the most important factors which influence the fatigue performance evaluation of metallic material. To quantitatively study this problem, two group of high strength transmission shaft steel with different inclusion level are selected to do the comparison fatigue test using stair case method. Experimental data shows that the inclusion of the metallic material will observably affect its fatigue performance. The comparative large size of Al₂O₃ inclusions with tip edge angle was found by stereo-scan and energy spectrum analysis, which were the sources of micro crack and lead the final fracture.

Abstract: The solidified structure refinement of Al-4.5%Cu under the action of low-voltage pulsed magnetic field (LVPMF) was investigated in the paper. The influences of different pulse voltage and pouring temperature on solidified structure of Al-4.5%Cu alloy were studied. The results show that solidified structure of Al-4.5%Cu alloy can be refined greatly by LVPMF processing. The dendrite growth is restrained and the microstructure is changed from larger dendrite grains to smaller nondendritic grains, and with certain parameters, the equiaxed, non-dendritic grains are gained in the alloy. With the increase of pulse voltage, grain size of the alloy decreases, and the primary phase degrades from developed dendrites into rose-like or spherical crystals. The decrease of pouring temperature enhances the refinement effect of LVPMF processing. With 150 V pulse magnetic field treatment, grain size of the alloy decreases, primary phase degrades and refines gradually with the decrease of pouring temperature.

Abstract: The geometry optimization, formation energy, Mulliken populations, and density of states of YAP (YAlO₃) crystal are studied by using first-principles method based on density functional theory. The optimal lattice parameters of YAP crystal are in good accordance with experimental results reported. The calculated formation energy (-3.73eV) indicates the excellent structural stability of YAP crystal. The obtained Mulliken charge populations of O, Al and Y atoms and their deviations from the formal ones, as well as overlap populations show YAP crystal is a mixed bond material with stronger ionic and weaker covalent bonds, which is attributed to the hybridization of atomic orbitals. The comprehensive effect of various interactions in the system makes YAP crystal more stable.

Abstract: The Green function and other complex functions were employed to study the problem of scatteing of SH wave by a interface semicircular debonded elastic lining of two-phase mediums and interface linear cracks originating at edge of lining. We divided the whole model into upper elastic half space with the semi-circular canyon and lower elastic half space with semi-circular lining hill.In lower half space. Semicircular debonded elastic lining is constructed by satisfing the continuous condition of displacement and stress on interface when upper half part and lower half part are conjoined,and linear cracks is constructed by using the method of crack incision, upper half part and lower half part are conjoined by method of “conjunction”.In the end some examples and results of dynamic stress intensify factor are given with discussions.

Abstract: Based on the service ambient with aluminium electrolysis condition, the evolution of compressive strength, elastic modulus and stress-strain curve of carbon cathode samples under various conditions are investigated by experimental simulation method; the deterioration mechanism of the mechanical of carbon cathode is also studied. Results show that different carbon cathode materials and ambient conditions have great influence on strength and elastic modulus of carbon cthode. The mechanical properties such as compressive strength and elastic modulus of carbon catodes can be degraded by the erosion of sodium and molten salt during aluminium electrolysis, that has been confirmation by the SEM and XRD analysis.