The single-phase SmyFexCo4-xSb12 compounds were synthesized by using the solid-state reaction method and melting reaction method, and the thermoelectric properties of SmyFexCo4-xSb12 were investigated. Research result...
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The single-phase SmyFexCo4-xSb12 compounds were synthesized by using the solid-state reaction method and melting reaction method, and the thermoelectric properties of SmyFexCo4-xSb12 were investigated. Research results indicated that the electrical conductivity of SmyFexCo4-xSb12 decreased with increasing Sm filling fraction, which the carrier concentration dramatically depends on. Seebeck coefficient increased with increasing temperature and Sm filling fraction. The lattice thermal conductivity decreased evidently with increasing Sm filling fraction, and reached the minimum value at a certain Sm filling fraction. The maximum figure of merit ZTmax of Sm0.19Fe1.47Co2.53Sb12 is 0.55 at 750 K.
Si-clathrate compounds, n-type Ba8 Ga16 Znx Si30-x (x = 0, 1, 2, 3, 4), are synthesized by using the solid-state reaction method and the melting method. The effects of the replacement of Si with Zn on the structure an...
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Si-clathrate compounds, n-type Ba8 Ga16 Znx Si30-x (x = 0, 1, 2, 3, 4), are synthesized by using the solid-state reaction method and the melting method. The effects of the replacement of Si with Zn on the structure and the electrical transmission characteristics are investigated for n-type Ba8Ga16Znx Si30-x. The results indicate that the sample with the value of x = 1 has the maximal bond angle distortion Δθ, Δθ = 4.4°. The electrical conductivity of samples with x = 0, 2, 4 is higher than that of samples with x = 1, 3. Among the samples, the electrical conductivity of Ba8 Ga16 Zn1 Si29 is the lowest. The samples with x = 0, 2, 4 exhibit a higher Seebeck coefficient than that of samples with x = 1, 3, and the value of the Seebeck coefficient decreases with the increase of the Zn composition. The power factor of Ba8Ga16Zn2Si28 compound is as large as 1.03 × 10-3 W/(m· K2) at 1000K.
High-energy ball mill method was used to fabricate the stainless steel nanocomposite powder from stainless steel powder, carbon powder and titanium powder as raw materials. The X-ray diffraction, SEM and the BET metho...
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High-energy ball mill method was used to fabricate the stainless steel nanocomposite powder from stainless steel powder, carbon powder and titanium powder as raw materials. The X-ray diffraction, SEM and the BET method were used to evaluate the microstructure of treated samples. The results showed that in vacuum condition, with ball mill time increase, stainless steel powder become more and finer, the grain size can reach nanometer level. At the same time, the nano TiC can be formed during ball milling, the stainless steel-TiC nano composite powder can be obtained.
Using the microwave sintering technology, the samples of WC-10Co cemented carbide were put separately at the pure electric field, the pure magnetic field and the mixture E field and H field in a single-mode TE103 cavi...
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Using the microwave sintering technology, the samples of WC-10Co cemented carbide were put separately at the pure electric field, the pure magnetic field and the mixture E field and H field in a single-mode TE103 cavity. The sintering behaviors of WC-10Co cemented carbide were researched and the effects of these positions on their properties also were analyzed.
Extensive dislocation structure was observed by transmission electron microscopy (TEM) in polycrystalline alumina ceramic sintered under a short-time high temperature 1800°C and pressure 100 MPa. There existed lo...
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Extensive dislocation structure was observed by transmission electron microscopy (TEM) in polycrystalline alumina ceramic sintered under a short-time high temperature 1800°C and pressure 100 MPa. There existed lots of dislocation structures: dislocation coalescence, dislocation arrays and dislocation network. The burgers vector of the dislocation array was determined by diffraction contrast as 1/3 less than or equal 11 over-bar 00>. The dislocation network formation was discussed, and it belonged to basal slip system l/3 less than or equal 112 over-bar 0>. Plastic deformation occured mainly by basal plane slip and prime plane slip.
In the present study, Si2N4 whisker was prepared by thermal decomposition of Si(NH)2, the experimental principles and process were described in detail. Influence factors such as temperature, residual carbon(C), a smal...
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In the present study, Si2N4 whisker was prepared by thermal decomposition of Si(NH)2, the experimental principles and process were described in detail. Influence factors such as temperature, residual carbon(C), a small quantity of oxygen and crucible material that could influence the growth of whisker was analyzed and discussed. The influence degree of each factor and mechanism were explained as well. High quality and modified Si3N4 whisker could be prepared by controlling the influence factors during the experimental process. As a result, it was significant to fabricate batch production of high performance Si3N4 whisker by utilizing this method.
Taking the running parameters of boiler drum in 8 typical working conditions as data of boundary conditions, the transient thermal stress, mechanical stress and total stress of a 300MW boiler drum is calculated by fin...
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Taking the running parameters of boiler drum in 8 typical working conditions as data of boundary conditions, the transient thermal stress, mechanical stress and total stress of a 300MW boiler drum is calculated by finite element method. The results show that when the vapor pressure is close to or higher than the normal working vapor pressure, the temperature difference on the boiler wall has little influence on the total stresses. The vapor pressure in boiler drum is the main influential factor to the total stresses, and there is a proportion relationship between them. With the relationship, the maximum stress in the drum can be calculated.
A one-dimensional multi-layer heat conduction model of CRAM is developed based on its memory principle. According to the read/write requirement of memory cell, and to the condition of its thermal compatibility with CM...
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A one-dimensional multi-layer heat conduction model of CRAM is developed based on its memory principle. According to the read/write requirement of memory cell, and to the condition of its thermal compatibility with CMOS circuits, the critical parameters are fixed on. The temperature profiles are portrayed by solving the heat conduction equation with the reasonable boundary conditions. Under the limitation of the critical parameters, we adjust the parameters of cell structure, use heating layer, and then develop the structural model of CRAM memory cell which not only meet the need of read/write function of memory cell but for the first time achieve the thermal compatibility of CRAM memory cell with CMOS circuits.
Mo/SiO2 composites with different mass compositions were sintered by spark plasma sintering (SPS) technique. The mechanism of sintering and densifications were studied and the relationship between the distribution of ...
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Mo/SiO2 composites with different mass compositions were sintered by spark plasma sintering (SPS) technique. The mechanism of sintering and densifications were studied and the relationship between the distribution of Mo in composites and the electrical property was discussed. The result indicated that there was no reaction between Mo and SiO2;the composites are mechanically mixed instead. Partly softened SiO2 and the particles of Mo filling the hole facilitated the compact of Mo/SiO2 composites. When the mass composition of Mo was less than 35%, the particles of Mo dispersed individually in SiO2 and the composite was an insulator;when that exceeds 40%, the composite was a conductor due to the connection of the particles of Mo.
Ti2AlC bulk material was synthesized by hot pressing using elemental powder mixture of Ti, Al and active carbon. X-ray diffraction (XRD) in different temperature of hot pressing was used to determine the phase composi...
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Ti2AlC bulk material was synthesized by hot pressing using elemental powder mixture of Ti, Al and active carbon. X-ray diffraction (XRD) in different temperature of hot pressing was used to determine the phase composition and scanning electron microscope (SEM) was observed to investigate the microstructure of samples synthesized respectively. Results show that high purity Ti2AlC bulk material was synthesized by hot pressing elemental powder mixture of 2.0 Ti/1.0 Al/1.0 C at 1500 °C for 60 minutes, in which little TiC and Ti3AlC2 existed as secondary phases. According to the results of thermodynamics calculation, for Ti, Al and C system the most stable compound in thermodynamics was TiC. Moreover, the formation of Ti3AlC2 during the synthesizing progress of Ti2AlC was explained.
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