Patterned ZnO nanorods have been first grown on patterned silicon nanocrystallite (SiNC) films that were fabricated on (100) orientation p-type boron-doped silicon wafer by hydrogen ion implantation technique and the ...
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Patterned ZnO nanorods have been first grown on patterned silicon nanocrystallite (SiNC) films that were fabricated on (100) orientation p-type boron-doped silicon wafer by hydrogen ion implantation technique and the anodic etching method, and their field emission properties were obtained. Field emission measurements demonstrated that the synthesized ZnO nanorods have excellent field emission properties, namely low turn-on field, low threshold field, and high emission spot density. The patterned ZnO nanorods have great potential in the application of flat panel displays.
In order to unclose the dynamics of SPS densification, a special sintering sample (Cu/Ti wires compact) was designed. Characters of the shrinkage rates during sintering process and microstructures of products fabricat...
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In order to unclose the dynamics of SPS densification, a special sintering sample (Cu/Ti wires compact) was designed. Characters of the shrinkage rates during sintering process and microstructures of products fabricated by the spark plasma sintering(SPS) and hot-press sintering were investigated. The experimental results reveal that a higher temperature field is formed at the connected area and conductive net of the compact. These high-temperature parts deformed more easily than other parts, which is believed to be the main cause of SPS fast densification, according to a hard-core and soft-hell material model.
Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly（N-vinyl-2-Pyrrolidone）.These nanoparticles were characterized by transmission electr...
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Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly（N-vinyl-2-Pyrrolidone）.These nanoparticles were characterized by transmission electron microscopy（TEM）,X-ray diffraction（XRD）,selected area electron diffraction（SAED）,as well as vibrating sample magnetometer（VSM）.The experimental results show that the addition of PVP and the concentration of NaOh have strong influences on the *** and uniformity of *** the presence of PVP and NaoH with low *** nickel nanoparticles with average diameters about 42 nm were obtained and characterized to the pure nickel crystalline with foc *** structures such as *** strings resulted from magnetic interactions between particles were *** chemical interaction between the PVP and nickel nanoparticles was found by *** saturation magnetization（Ms）.remanent magnetization（Mr）and coercivity（Hc）of these nickel nanoparticles are lower than those of bulk nickel.
ZrB2 ceramics were prepared by self-propagating high-temperature synthesis（SHS） and were sintered by hot pressing（HP）.The effects of the granularities and doses of raw materials in Zr-B2O3-Mgon SHS process and pro...
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ZrB2 ceramics were prepared by self-propagating high-temperature synthesis（SHS） and were sintered by hot pressing（HP）.The effects of the granularities and doses of raw materials in Zr-B2O3-Mgon SHS process and product were *** and combustion temperature curves prove that the ideal SHS reactants of Zr-B2O3-Mg are 50μm Zr powder,75μm B2O3 powder and 400μm Mg powder with 45% *** particle sizes of SHS product,acid-leached product,sintered product are 2-5μm,0.5-2μm,2-10μm *** analysis indicates that the acid-leached product consists of ZrB2（94.59%）,ZrO2（3.87%）,and H3BO3（1.54%）,The sintered product has a relative density of 95.4%.
The flow field is very important for the proton exchange membrane fuel cell (PEMFC). In this paper the PEMFC with different kind of section channels is modeled and optimized design by the PEM module of the Fluent soft...
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The flow field is very important for the proton exchange membrane fuel cell (PEMFC). In this paper the PEMFC with different kind of section channels is modeled and optimized design by the PEM module of the Fluent software. And the result shows that the performance of the PEMFC with rectangle, semicircle, triangle or trapezoid section is not too much difference, but the performance of the PEMFC with changing section channel is much better than that of the above mentioned ones.
Titanium diboride based composites, good candidates for contact materials, have high hardness, Young＇s modulus, high temperature stability, and excellent electrical, thermal conductivity. However a good interface of ...
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Titanium diboride based composites, good candidates for contact materials, have high hardness, Young＇s modulus, high temperature stability, and excellent electrical, thermal conductivity. However a good interface of TiB2/Cu is very difficult to achieve for oxidation of TiB2. To avoid this oxidation behavior, the in situ combusting synthesistechnology, SHS, was used to prepare TiB2/Cu composite. The characters of Ti-B-xCu SHS were studied in detail, such as combustion temperature, products phases and grain size. Based on the experimental results a proper technology way of self-high temperature synthesis plus quick press （SHS/QP） was determined and compact TiB2/Cu composites with relative density over than 97 pct of the theoretical were fabricated by this method. The properties and microstructures of these TiB2 based composites were also investigated.
TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition...
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TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition was summarized. Scan electron microscope of JSM-5610LV and transmission electron microscope of H-600STEM/EDS were used to observe the microstructure of coated powders. Results show that treatment time, rotation speed, granularity ratio of TiB2 to BN, pretreatment of materials etc influence the coating results evidently. Mixing raw materials and coating with BN under the appropriate condition can get round TiB2/BN composite powder with smooth surface and compact coating layer.
When boiler runs under certain pressure and temperature, the disfigurement and crack will propagate, resulting in failure of the boiler drum. According to the Assess criterion of Pressure Container's Disfigurement...
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When boiler runs under certain pressure and temperature, the disfigurement and crack will propagate, resulting in failure of the boiler drum. According to the Assess criterion of Pressure Container's Disfigurement, the maximal stress value in the dangerous area for 125MW boiler drum and its change within certain time frame under different working conditions are found out by means of finite element method. The allowable length of crack is calculated with COD mode and the yearly crack-propagating value is predicted and analyzed.
Based on the boundary conditions of the running parameters and test data of 125 MW boiler drum, the transient thermal stress, mechanical stress and whole stresses of the boiler drum under four different working condit...
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Based on the boundary conditions of the running parameters and test data of 125 MW boiler drum, the transient thermal stress, mechanical stress and whole stresses of the boiler drum under four different working conditions were computed by finite element methods under 3-dimension model. The relationship among the three kinds of stresses was discussed as well as the spot of maximum stress and its varying tendency with the time was obtained.
The residual stresses on the surface of the d ifferently ground and polished silicon nitride ceramics were measured using X-r ay diffraction and identified by *** effect of the residual stress on the be nding strengt...
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The residual stresses on the surface of the d ifferently ground and polished silicon nitride ceramics were measured using X-r ay diffraction and identified by *** effect of the residual stress on the be nding strength was *** investigations show that the grinding proces s can introduce subatantial tensile residual stresses up to 290MPa on the surfac e of silicon nitride ceramics,which has a significant effect on reducing the ben ding strength of the ceramics after ***,in comparison with the ceramic s with a rough surface,the ceramics with a mirror image surface may have a lower *** can smooth the residual *** we evaluate the qualit y of the ceramic components after grinding,we must take residual stress into con sideration. The grinding methods and grinding conditions must be carefully selec ted in order to get the favorite residual stress as well as the surface smoothne ss.
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