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Rapid preparation of nanocrystalline γ-Fe2O3 powder with superparamagnetism was realized by cryomilling commercial Fe2O3 powder using liquid nitrogen. The effects of milling temperature and duration on the grain size, phase and microstructure of the nanocrystalline Fe2O3 powder were analyzed. Magnetic property of the nanocrystalline γ-Fe2O3 powder was also tested by magnetometer at room temperature. The results demonstrate that nanocrystalline γ-Fe2O3 powder with single phase can be prepared rapidly by cryomilling with liquid nitrogen. The mean particle size of γ-Fe2O3 powder can be reduced from 300 nm to 13 nm by cryomilling at −130 °C within 3 hours. The nanocrystalline γ-Fe2O3 powder shows superparamagnetism at room temperature.

The effect of applied forging pressure on microstructure and mechanical properties of 6061 aluminum alloy was examined. The results showed that the ultimate tensile strength, elongation and hardness of the alloy after heat-treated treatment increase with the applied forging pressure, and the corresponding highest values, 365MPa, 11.52% and 146.53HV, were obtained at the applied forging pressure of 120MPa. Compared to casting condition without forging pressure, the ultimate tensile strength, elongation and hardness can be increased by 22.8%, 98.2% and 48.7%, respectively. The defects such as the shrinkage pores and cracks were absent in the microstructure due to the applied forging pressure. The SEM observation indicated that the fracture mode of 6061 aluminum alloy is more ductile at higher applied forging pressure.

To solve the problems of installed trival, resource waste, hammerhead falling off and improve the poor abrasion resistance of hammer handle under the crusher hammers working condition, the new combined type crusher hammers were designed by connecting separated hammer handle and separated hammer head. When hammer head were worn badly, we just replaced hammer head and don't have to remove the shaft rod. This design can save a lot of time and labor force, improve production efficiency and we can save a lot of resources by reusing the hammer handle; At the same time, hammer tip was casted with liquid-liquid bimetal composite casting technology of casting, under the premise of guaranteeing the wear-resisting, which can also ensure that the impact toughness of the joint. Validated by actual working condition, hammer handle can be replaced at least five times for this design of hammer, and each group has 24 hammer heads, every 5 sets of hammer heads can save 1200 kg metallic materials, 1800 KWh and CO2 emissions dropped by 1795 kg.

The cloud storage is the evolution of the cloud computing system, which is based on data storage and management. This thesis is focused on the discussion of the cloud storage model that is built on the Cloud Storage Access Protocol of SNIA, and puts forward the concept of storage pooling at storage management layer with unified virtualization and dynamic management on physical storage devices. The thesis also compares the typical DFS (Distributed File System) on the data management layer in different data conditions.

With the development of cloud computing, cloud storage distributed the endless file system,but not a better copy strategy compatible with various file systems.This paper proposed ontology-based metadata replica which make different file systems mutual fusion ,and give a policy of replica allocation of low-load access .

According to the hammer crusher working condition, a kind of dual liquid bimetal composite casting hammer was developed. Its service life is three times than that of high manganese steel. It improves the wear resistance and increases production efficiency significantly, and is welcomed by user deeply.

The optimization database of radiation protection was designed on nuclear facilities maintenance with SQL Server 2008 in this paper. The database includes four modules, namely system login module, statistical data module, daily module and optimization module. Twenty-three data tables were designed, which could store a mass of data in orderly. The optimization database of radiation protection on nuclear facilities maintenance could store the original monitoring data such as plant radiation levels measurement figure on nuclear facilities for maintenance and maintenance daily. This database also combines with the actual demand in the engineering project to statistics and analysis the data.

Material wear such as abrasiveness, cavitations erosion, and grinding balls with large diameter etc, exists during the usage of ball mill lining board. The effect of the chemical contents, composite casting process and heat treatment parameter on the interface microstructure, mechanical properties and wear resistance were studied by the SEM, EDAX and TEM, etc. The results show that the bimetal interface formed an effective metallurgical bonding boundary without mixing. The impact toughness of the interface is higher than the working face. The bimetal composite lining board has a very good stability. The service life of the bimetal lining board is increased 70% than the medium carbon low alloy steel under the same service conditions and the process yielding is over 95%.

Hot compression test of coiled tubing steel is performed on Gleeble3500 at 1123K—1373K and strain rate from 0.001 to 5s-1. The hot deformation behavior of coiled tubing steel was characterized using processing map developed on the basis of the dynamic materials model. The processing map gives the flow instable region and the flow stable region in which the process of dynamic recovery (DRV) and the dynamic recrystallization (DRX) occur. In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and the strain rate. According to the processing map, the coiled tubing steel is rolled by The Thermo-Mechanical-Control-Process (TMCP), and finally it is obtained that the yield strength and tensile strength of coiled tubing steel are 565MPa and 685MPa respectively, and the elongation percentage is 32.1%.

Mechanical properties of extruded Mg-Zn-Nd-Y-Zr alloy are investigated by tensile tests at various temperatures range from room temperature to 350°C with strain rates of 6.0×10-4-6.0×10-1s-1. It is found that the peak decrease with increasing temperature and decreasing strain rate, while the elongation increases with increasing temperature and decreasing strain rate. When deformation temperature is over 250°C, superplasticity occurs. This is ascribed to grain boundary sliding accommodated cavities growth. . At low temperature, the peak stress are a relatively higher than that of ZK60 alloy. This is explained by the grain refining effect and the precipitates of Mg9Nd and Mg6Zn3Y2.

Precise analysis on large-span spatial structures depends on accurate numerical material constitutive model, According to the axial tension stress-strain curve, the paper proposes a new numerical multiline material model, with material effects of intenerating effect, material hardening effect and damage effects considered, and corresponding calculation method applicable to beam element. Simulation of axial tension test and bi-level loading test on cantilever column proves that the material model and algorithm are effective and correct.

The steel-plate-masonry composite structure is an innovative type of structural scheme popular in masonry structures with load-bearing walls removed for a large space. A total of 4 column specimens under static loading were tested to mainly study the failure modes, load-carrying capacity, and strain distribution in the critical cross-section. Results show that the composite columns started an initial failure from local buckling of the steel plate located between binding bolts; the main factors influencing load-carrying capacity included thickness of the steel plate, type of injected material, and initial column eccentricity; the working performance of the composite column with epoxy adhesive was better than that with cement grout; and re-distribution of compressive stress existed in the steel plates of the column. Also, the ratio of service load-carrying capacity to ultimate capacity of the steel-plate-masonry composite column is about 70%.

This paper demonstrates the natural frequency varying rule with differently critical design parameters for the free vibration characteristics and change features of structural response with different geometric parameters under the simple harmonic excitation.

Aging treatment of Cu-17Fe alloy was investigated by a vacuum heat treating furnace in high magnetic furnace. The microstructures were documented using scanning electron microscopy (SEM). The solid solubility of Fe in Cu matrix was analysed by energy spectrometer (EDS). The mechanical properties were measured with a Vickers hardness tester. The electrical conductivity was measured with a micro-ohmmeter. The results showed that high magnetic field can promote spheroidization of the Fe dendrites, the spheroidization intensifies and the solid solubility decreases with the increasing magnetic induction intensity of the high magnetic field exerted to the alloy, the solid solubility of Fe is minimum when the magnetic induction intensity is 10T at 500°C during precipitation. And Cu-17Fe alloy has a good strength/conductivity combination of 110Hv/63%IACS after aging treatment of 10T at 500°C for 1h.

The static stability capacity is the main index to measure the whole mechanical performance of single-layer latticed shells. Three single-layer cylindrical latticed shells with different height to span ratio were modeled, and their seismic damage were assessed by the degradation of static stability capacity incurred by earthquakes. Two different static load patterns were considered: dead load and the combination of dead load and half span live load. The results show that the damage assessment method is applicable to single-layer cylindrical latticed shells, and the static load patterns have no big influence on the damage assessment of the single-layer cylindrical latticed shells.

To analysis progressive collapse behavior of single-layer reticulated shell under severe earthquake, based on spatial fiber beam element failure criteria, a simulation method on progressive collapse of shell is presented, which account of mechanical properties of components after buckling and damage accumulation effect of combine hardening material. And a computation program is developed correspondingly. At last the method and program proves to be applicable by an example.

For the purpose of investigations of the different situations when the cells of Acidianus manzaensis can or can not attach the surface of the chalcopyrite. Three experiments were carried out in the modified shake flasks, and in one of the experiments the cells could not attach the surface of the chalcopyrite, but could participate in the solution chemistry of the process. The redox potential, pH, cell density, copper, ion and thiosulfate concentration in the solution were monitored in the experiments, and the morphological feature and chemical composition of the leached residues were analyzed by SEM and XRD. The most leach effiency of Cu and Fe was reached in the experiment that the Acidianus manzaensis could attach the surface of the chalcopyrite. However, the unattached Acidianus manzaensis could also leach the chalcopyrite, but it was less actively than attached cells. There was no precipitation of jarosite in the leached residues of the three experiments, but there was sulfur in the leached residues when the cells could not attach the chalcopyrite. So the surface passivating layer of sulfur can be removed only when the Acidianus manzaensis can attach the surface of the chalcopyrite. From these results it become apparent that the leach of the chalcopyrite is the cooperative action of the attached and unattached Acidianus manzaensis.