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排序方式: 共有655条查询结果,搜索用时 125 毫秒
1.
《Ceramics International》2022,48(18):26022-26027
Aluminum nitride (AlN) is used a ceramic heater material for the semiconductor industry. Because extremely high temperatures are required to achieve dense AlN components, sintering aids such as Y2O3 are typically added to reduce the sintering temperature and time. To further reduce the sintering temperature, in this study, a low-melting-temperature glass (MgO–CaO–Al2O3–SiO2; MCAS) was used as a sintering additive for AlN. With MCAS addition, fully dense AlN was obtained by hot-press sintering at 1500 °C for 3 h at 30 MPa. The mechanical properties, thermal conductivity, and volume resistance of the sintered AlN–MCAS sample were evaluated and compared with those of a reference sample (AlN prepared with 5 wt% Y2O3 sintering aid sintered at 1750 °C for 8 h at 10 MPa). The thermal conductivity of AlN prepared with 0.5 wt% MCAS was 91.2 W/m?K, which was 84.8 W/m?K lower than that of the reference sample at 25 °C; however, the difference in thermal conductivity between the samples was only 14.2 W/m?K at the ceramic-heater operating temperature of 500 °C. The flexural strength of AlN–MCAS was 550 MPa, which was higher than that of the reference sample (425 MPa); this was attributed to the smaller grain size achieved by low-temperature sintering. The volume resistance of AlN–MCAS was lower than that of the reference sample in the range of 200–400 °C. However, the resistivity of the proposed AlN–MCAS sample was higher than that of the reference sample (500 °C) owing to grain-boundary scattering of phonons. In summary, the proposed sintering strategy produces AlN materials for heater applications with low production cost, while achieving the properties required by the semiconductor industry. 相似文献
2.
K. Borer G. Czapek F. Hasenbalg M. Hauser S. Janos P. Loaiza U. Moser K. Pretzl C. Schütz P. Wicht S. Wüthrich 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2004,520(1-3):112-115
The ORPHEUS dark matter detector consists of 450 g superconducting tin granules with diameters of 28 and 36 μm. The detector has been operating in the shallow site of the underground laboratory in Bern (70 m.w.e). First preliminary results on WIMP detection sensitivity will be presented. 相似文献
3.
A cryo-specimen storage system for low-temperature scanning electron microscopy (LTSEM) specimens is described, which: liberates multi-specimen experiments from sampling restrictions imposed by the rate at which LTSEM specimens can be examined in the SEM; provides security against experiment loss resulting from breakdown of the SEM or cryo-system; enables collection of specimens in the field or in laboratories remote from the SEM laboratory; and facilitates international air transport of LTSEM specimens. The components of the system, which has a capacity of 98 stub-mounted specimens, are readily made in a laboratory workshop. The details of the design may be altered to suit particular specimen types or experimental approaches. 相似文献
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对低温器件计算机模拟方法作了具体的考虑。从求解变量和半导体物理意义出发,数值计算结果事先有一个定性范围,如果每一次循环的迭代初值都修正到这个数值范围内,那么选代过程将以更快的速度接近真解。提出了适用于低温半导体器件计算机模拟的增量限制方法,并且将该方法插入MINIMOS4.0进行了数值实验。结果表明,设置增量限制能保证低温半导体器件模拟的数值收敛性,并巨有较快的收敛速度。 相似文献
6.
中央空调低温送风的系统设计方法 总被引:1,自引:0,他引:1
本文对中央空调低温送风系统的设计方法与常规空调进行比较,分析了低温送风系统设计中应该注意的问题,以使系统更节能、高效、合理。 相似文献
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8.
《Fuel》2002,81(9):1161-1169
A combination of techniques was used to characterize the inorganic constituents of four types of vegetable biomass: apple pulp, olive cake, olive tree prunings and thistle. Two methods were used to selectively eliminate organic matter: low-temperature oxidation in an oxygen plasma, and medium-temperature oxidation in air. Inorganic species present in the residues were identified by X-ray diffraction and FT-IR spectroscopy.The combination of these techniques allowed one to detect SiO2, CaCO3 and various other Ca-, Mg-, Na- and K-containing phases as inorganic constituents of the studied biomass residues. It is concluded that the oxygen plasma treatment produces sulphates and nitrates that were not present in the starting material. Medium-temperature oxidation does not produce these artificial species but induces some thermal transformations in the mineral constituents of biomass, so that each technique has its own advantages and disadvantages. 相似文献
9.
低温快烧金光釉的研制 总被引:4,自引:0,他引:4
作者以正交试验法研究探讨了多种金属氧化物对金光釉产生金属光泽及釉面质量的影响,采用快速烧成的工艺探索了金光釉快速烧成的可行性,并在氧化还原不同的气氛下验证了金光釉对气氛的适应性,从理论上分析了金光釉产生金属光泽的机理。 相似文献
10.
A circulating slurry bubble reactor was developed to synthesise methanol via methyl formate from the gas mixture of carbon monoxide and hydrogen at low temperature. The strategy for designing and scaling up the bubble reactor involved a preliminary understanding of fluid dynamics in a cold model, continuous operations under industrial conditions and a parallel experiment in an autoclave. Per-pass syngas conversion was investigated during 100-h operations. The axial profile of solid catalyst concentration was measured just before the shutdown and the composition of liquid product was analysed after the shutdown. These results show that the circulating slurry bubble column will become a potential reactor for the commercial process of low-temperature methanol synthesis after the catalyst system has been improved. 相似文献