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In this paper, carbon coated spherical Mn3O4 was prepared by decomposition of spherical MnCO3 and sucrose. The results of XRD and SEM showed that Mn3O4/C composites are sphere-like with good crystallinity, and its diameter is about 1um. It could deliver a reversible charge capacity of 848.7 mA h g-1 at the current density of 162.3 mA g-1, and the specific discharge capacity is still have 441 mA h g-1 at a high current density of 649.4 mA g-1 exhabiting good rate performance. The excellent performance of the spherical Mn3O4/C composites could be attributed to its unique architecture which provides fast lithium ion and electron transportation as well as accommodates the large volume change of transition metal oxides during conversion reactions.

This paper describes a proper low cost way to fabricate defects free porous carbon preforms with interconnect pore structure for making reaction formed SiC (RFSC). Taking charcoal , poplar powder, camphene and polymer dispersant together, making slurries by milling under 55 °C for several hours, controlling the content of charcoal and poplar powder, after casting, sublimating and carbonizing, the porous carbon performs with a series density (0.66 g/cm3-0.78 g/cm3) and porosity (62.9 vol.%-68.6 vol.%) were prepared; through the Si infiltrating process under a vacuum condition (~5.0 Pa) at 1500°C for about 0.5 hour, the RFSCs with fine mechanic performance were fabricated, one RFSC sample has the density, Weibull modulus, and the max three points flexural strength is 2.91 g/cm3, 9.5 and 505.0 MPa respectively.

In this paper, high volume fraction SiCp/Al composite was fabricated by pressureless technique with silicon carbide porous preform which fabricated through gel casting process. The effects of solid loading on the rheological properties of SiC slurry were discussed. High solid loading SiC slurry of 65vol% with low viscosity and high stability was fabricated. Also microstructure, flexural strength of the SiC preform and SiCp/Al composite were studied, the results showed gel casting process and pressureless infiltration technique were suitable for fabricating high volume fraction, homogeneous structure and high performance SiCp/Al composite.

The 3D printing ceramic body was prepared by camphene carbon/silicon carbide slurry, which were prepared with camphene, carbon and silicon carbide, dispersant, binder as rawmaterial, according to certain stoichiometric ratio. The effects of the choice of dispersants on the dispersion of the slurry performance were investigated. The amount of dispersant were determined.

CVD SiC material with many excellent physical and chemical properties was used widely in the field of aerospace as reflector materials. In addition, CVD SiC thin film materials because of its compact structure, high purity can also be used as precision optical components of semiconductor industry. But the CVD process is a complex chemical process and the reaction process is very time consuming. Research of chemical vapor deposition for preparing silicon carbide process mechanism is important significance for the expansion of the application of silicon carbide. In this paper, CVD SiC coatings were fabricated by the pyrolysis of methyltrichlorosilane (MTS) in hydrogen at a low pressure. XRD and EDS were used to characterize the component of intermediate. SEM was used to observe the surface morphology and microstructure of coatings. The results indicated that key problem to be solved is to control the growth rate of SiC for high quality deposition coating, while the growth rate is also affected by process parameters. To obtain the materials to meet the use requirements, the need for control of each parameter in the reaction process.

Aimed at the applications of technology of camera calibration to 3D reconstruction, the ideal camera model is discussed, especially on the influences and solving methods of lens radial distortion andtangential distortion, and an arithmetic of camera calibration based on OpenCV (open source computer vision library) in Visual C++ environment is given. This arithmetic makes use of the functions of the library effectively, so it has high calibration precision and good robust. It can meet the needs of august reality and othercomputer vision systems.

How to improve the success rate of the industry-university-research cooperation and form a benign circulation, is the primary topic of current research studies, reasonable investment in research and development is an important guarantee for sharing research results between enterprises and scientific research institutes. It applies the dynamic information game to analysize the input relation between the enterprise and the scientific research institute in the process of the industry-university-research cooperation, and demonstrates the effect of the collaborative pattern on the profit reliezation of the both sides.

High thermal conductivity and dense SiC coating were fabricated by chemical vapor deposition (CVD) on surface of different graphite at temperature of 1100°C. The results indicated that the thickness of the coating influences the quality of coating. There was no crack in coating when thickness of the coating is less than 0.3mm. The structure of graphite affected the reaction badly. When the graphite is coarse and porous the reaction is chemical vapor infiltration (CVI) and the interface of coating and substrate isnt obvious. When the graphite is dense and smooth, the coating is covered in surface of graphite, the interface is found between the coating and substrate. Optical microscope and SEM were used to observe the surface and cross-section morphology and microstructure of coatings. It shown coating and substrate had a good combination and the deposited grains mainly showed equiaxed form with the crystallite size of 30 nm at 1100°C.

The chambers of certain coal mine in Shandong such as central substation situate in soft rock which consists of mudstone and fine sandstone, etc. Obvious ground pressure behaviors, large deformation and failure of surrounding rock have serious effect on mine safety production, with the impact of various complicated deep large ground pressure. This paper presents a rational scheme to control the surrounding rock steadily, based on analysis of deformation and failure on large section soft rock chamber, combined with the concept of the" combined supporting technology of long and short anchors" and "the combined supporting technology of three anchors".

PP/PA6/APP/OMMT Nanocomposites were Prepared via One-Step and Two-Step Melt Intercalation. the Flame Retardation, Thermostability, Structure Characters and Hygrothermal Aging Properties of PP/PA6/APP/OMMT Nanocomposites were Studied by UL-94, OI, TG and TEM. the Results Show that Two-Step can Improve the Flame Retardation of PP/PA6/APP/OMMT Nanocomposites; when OMMT Content is 4% or 6%, the Flame Retardation Gets Tofv-0, and the Lois are 32.2% and 32.8% Respectively; OMMT Doesn’t Play an Obvious Role to Hygrothermal Aging of PP/PA6/APP/OMMT Nanocomposites.

This paper presents RandomBug, a novel real-time path planning algorithm, for an autonomous mobile agent in completely unknown environment. According to this algorithm, all the planned paths are described and stored in the form of vectors. When the agent moves along the planned paths, it only considers the rotation angle and the movement distance in a single direction. The algorithm combines range sensor data with a safety radius to determine the blocking obstacles and calculate the shorter path by choosing the random intermediate points. When there is obstacle blocking in the current path, the intermediate points will be calculated randomly and the planned path will be regenerated by inserting the selected random intermediate points. Simulation results are given to show the effectiveness of the proposed algorithm.

T coordinate formation control for multiple underactuated AUVs. An optimal performance index is proposed to give attention to both tracking quality and formation constraint. A reference feasible trajectory for the position and orientation based on velocity control is planned so that it is consistent with vehicle dynamics. And the performance index is transformed to the error one. The optimal controller is designed to solve the problem. Using the controller we demonstrate the physical realization of control system at the same time. Simulation results validate that the proposed formation methodology are presented and discussed.

The heat sink has played an important role in the thermal design of high power LED lamps. In this study, a pin-fin heat sink is designed for the 3-chips high power LED down-light. Thermal performance of pin-fin heat sink is researched by changing the fin height, fin number and lamp’s irradiation angle. Simulation results gotten by CFD software show that the pin-fin heat sink has better thermal performance with fin height of 40mm and fin number of 75. The LED down-light with a pin-fin heat sink has a better cooling effect in multi-angle irradiation. The results provide a reference for future design of pin-fin heat-sink.

A kind of porous SiO2 bulk materials with pore size distributed in nano and micron scales has been fabricated by freeze-casting of SiO2 nano-size powders in TBA (tert-butyl alcohol)/H2O suspensions. The content of TBA in the well mixed TBA/H2O binary co-solvent plays an important role in size and morphology control of the pores in the obtained SiO2 monolithic materials, since the ratio of TBA/H2O determines the competition of crystallization of TBA and ice, therefore, the microstructure of the monolithic SiO2. It was found that the content of TBA in the range from 30 to 40% was suitable for formation of more nano-pores in the SiO2 monolith. The insulation materials freeze-casted from the suspension of SiO2 in 13wt% and TBA in 40wt% has the density of 0.17g/cm3, and the specific surface area of 282m2/g. The pore size has a trimodal size distribution with three mean diameters of 15nm, 100nm and 4μm, respectively.

Experiments were carried out to join reaction-bonded silicon carbide (RBSC) ceramic in green body. SiC green bodies were fabricated by gel-casting method. The slurries for joint were prepared by different grain size of SiC. The results indicate the solid loading and the grain size of SiC influence the strength of welding. There is no clear welding interface between the two substrates in an appropriate solid volume loading and grain size. The average bending strength of welding after sintering can reach 300MPa. SEM was used to observe the cross-section morphology and microstructure of binding sites. The test result shows that its microstructure is similar to the RB-SiC ceramic. The mechanical properties of binding sites were tested. The result shows a desirable mechanical property.

The porous carbon preforms with fine pore structure has been successfully fabricated by room temperature freezing casting, and the reaction formed SiC with fine mechanical property has prepared successfully by liquid silicon infiltration process. Charcoal powder was used as carbon resource, camphene was used as sublimate vehicle, methyl cellulose was used as pore maker and bonder. The result shows that the homogeneity of the porous carbon preform has been improved largely by adding methyl cellulose ,and the defects of reaction formed silicon carbide has reduced largely also. The density, average flexural strength and Weibull modulus of the best reaction formed silicon carbide prepared in this paper is 2.86 g/cm3, 430.75MPa and 9.29 respectively.

In this paper, gel casting process of RBSC was deeply studied. The rheological property of C/SiC slurry was analyzed, high solid loading (67%) slurry with low viscosity was produced. Also the properties of green body and sintered body were studied. Finally, through optimizations of process parameters, a large-sized (650mm), complex-shaped (with thin ribs about 2.5mm) was fabricated through gel casting process with no cracks and deformation. It was showed that gel casting process is suitable for producing large-sized, complex-shaped RBSC components.

This paper describes the fabrication of porous reaction-bonded SiC ceramics with radial directed pores and the application of these materials to transpiration cooling system of rocket engines. A special mold is designed for freeze-casting process to prepare SiC cylinders with radial directed pores. Green bodies with well-oriented pore structure are obtained from slurry with solid loading up to 47vol%. The pore size is in the level of several tens micron. Green bodies with various porosities are infiltrated with different amount of liquid Si. The intrinsic permeability of each sample is measured with air as flowing media. It is concluded that permeability has relationship with not only the porosity but also the pore structure of samples.

Silicon carbide ceramic has many attributes including high strength and stiffness, low thermal expansion coefficient, high thermal conductivity, low density and good resistant for radiation of space particles. These attributes make SiC ceramic becoming the third generation space mirror material. This paper describes the fabrication of lightweight SiC mirror blanks. By reducing the shrinkage of green body and controlling the drying conditions, lightweight SiC mirror blank with a diameter of 612mm has been prepared by using gelcasting process. The forming green body is infiltrated with liquid silicon at the temperature of 1600°C, then a CVD SiC layer is coated on the surface of SiC mirror blank. After grinding and polishing, the mirror shows good optical properties.

Porous ceramics green bodies of silicon carbide were formed by freeze-casting of silicon carbide/carbon black aqueous slurries in a mold where temperature distribution was controlled. The influence of solid loading on the pore structure of green bodies was investigated. Pore morphology of green bodies formed from slurries with various solid loading ranging from 25 to 50vol% experienced a gradual change. Appropriate solid loading of silicon carbide/carbon black slurry was concluded for fabrication of SiC ceramics with oriented pore structure. Two means were employed for changing ice crystallizing velocity, so that the influence of ice crystallizing velocity on pore size of green bodies was explored. It was concluded that pore size became larger under slow freezing condition, whereas smaller with the pre-cooling of silicon carbide/carbon black slurry.

This paper describes the investigation of gelcasting of silicon carbide/carbon black aqueous slurry. Aqueous slurries are prepared by using polyvinylpyrrolloidone and tetramethyl ammonium hydroxide as dispersants. Rheological behaviors of the slurries have been studied. Two initiator systems are used to initiate free-radical polymerization of acrylamide in silicon carbide/carbon black aqueous slurry. In order to reduce strong effect of carbon black on inhibiting polymerization of acrylamide, acetylacetone is added into the slurry. The experimental result shows that controllable free-radical polymerization of acrylamide in silicon carbide/carbon black aqueous slurry can be realized by adding small quantity of acetylacetone.

In this paper, the green RBSC was prepared by gel casting process. The influences of the monomer content (MBAM and AM) and monomer ratio (MBAM to AM) on the flexural strength were investigated. The results indicated the flexural strength of green body was up to 8MPa and the micro- structures were homogeneous. The green RBSC bodies were machined by CNC grinding machine with diamond-coated grinding tools. Machining tests showed the green component could be machined without appended defects. It was found that green machining as a ‘top-down’ approach was a potential alternative for the rapid fabrication of complex-shaped ceramics, especially for some one-of-a-kind products.

The Cf/SiC made from carbon fiber preforms infiltrated by phenol resin, pure carbon slurry and aqueous C/SiC slurry showed different binding strength between carbon fiber and SiC matrix, thus influenced the fracture behavior of the composite. The fracture toughness of the Cf/SiC composites with the value of 9.82MPa•m1/2,improved remarkably compared with reaction- bonded silicon carbide (RBSC). But the flexural strength was less than 100 MPa, because of the existence of considerable amount of pores in C/SiC composites.

A SiC coating was chemical vapour deposited (CVD) on a Cf/SiC composite with the ratio of H2 and methyltrichlorosilane (MTS) changed gradually from 6:1 to 12:1 during the CVD processing. Energy-dispersive spectrometry (EDS) of the coating showed that the content of C decreased while Si increased continuously from the interface between coating and Cf/SiC substrate to the outside surface of coating. The obtained compositionally graded structure effectively reduced the generation of microcracks by releasing the mismatch of CTE of the coating and the composite.

In this paper, green bodies of RBSC were prepared through the gel-casting process. The effects of monomer concentration and ratio of MBAM to AM on the strength and microstructure of the green bodies were studied. When the monomer content increased from 10wt% to 20wt %( relative to water in the slurry), the flexural strength increases efficiency. However, the flexural strength decreases when the monomer content was above 20wt%. Similarly, when the ratio of MBAM to AM increased from 1/19 to 1/9, it had the same effects on the flexural strength of green bodies. It was found that silicon carbide particles were packaged by the carbon particles with gel. When the monomer content was 20wt% and the ratio of MBAM to AM was 1/9, the green body showed the best homogeneous microstructures and its flexural strength achieved 8MPa.

The application and the transpirational behavior of oriented porous SiC as transpiration cooling materials in a simulating test were studied. The test sample was shaped by freeze-casting process and reaction sintered. The testing device was composed by an electric arc combustor and a hydrogen coolant providing system. It was found that the permeability, the amount of coolant required and the uniformity of coolant infiltration were all effected by the microstructure of porous SiC, which furthermore influced the cooling efficiency of the testing system. In this test, the inner face temperature of the combustion chamber was maintained less than 400K throughout the thermal testing period contrasting with the fire temperature up to 3600K by the utilization of oriented porous SiC transpiration cooling materials.