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排序方式: 共有116条查询结果,搜索用时 15 毫秒
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Xian Xue Xiaofeng Yuan Rong Ma Qibin Yuan Hong Wang 《Journal of the European Ceramic Society》2019,39(13):3744-3748
In this study, the novel temperature-stable (1-x)Ag2MoO4-xAg0.5Bi0.5MoO4 microwave dielectric ceramics were prepared by a modified solid-state reaction method. The phase composition, microstructures and microwave dielectric properties of the (1-x)Ag2MoO4-xAg0.5Bi0.5MoO4 ceramics were investigated. All the compounds can be sintered well at ultra-low temperatures (<540 °C). The XRD and SEM analysis indicate that the Ag2MoO4 and the Ag0.5Bi0.5MoO4 can coexist with each other. When x = 0.65, the ceramics exhibit the best microwave dielectric properties with a relative permittivity of 23.9, a Q × f value of 16,200 GHz (at 7.3 GHz) and a near-zero TCF value of -2.4 ppm/°C at 520 °C. The results indicate that temperature-stable (1-x)Ag2MoO4-xAg0.5Bi0.5MoO4 ceramics are promising candidates for low temperature co-fired ceramics (LTCC) applications. 相似文献
3.
Ashish Ganvir Mohit Gupta Nitish Kumar Nicolaie Markocsan 《Ceramics International》2021,47(1):272-283
This paper investigates the influence of suspension characteristics on microstructure and performance of suspensions plasma sprayed (SPS) thermal barrier coatings (TBCs). Five suspensions were produced using various suspension characteristics, namely, type of solvent and solid load content, and the resultant suspensions were utilized to deposit five different TBCs under identical processing conditions. The produced TBCs were evaluated for their performance i.e. thermal conductivity, thermal cyclic fatigue (TCF) and thermal shock (TS) lifetime. This experimental study revealed that the differences in the microstructure of SPS TBCs produced using varied suspensions resulted in a wide-ranging overall TBC performance. All TBCs exhibited thermal conductivity lower than 1 W/(m. K) except water-ethanol mixed suspension produced TBC. The TS lifetime was also affected to a large extent where 10 wt % solid loaded ethanol and 25 wt % solid loaded water suspensions produced TBCs exhibited the highest and the lowest lifetime, respectively. On the contrary, TCF lifetime was not as significantly affected as thermal conductivity and TS lifetime, and all ethanol suspensions showed marginally better TCF lifetime than water and ethanol-water mixed suspensions deposited TBCs. 相似文献
4.
透明导电薄膜对太阳能平板集热器性能的影响 总被引:1,自引:0,他引:1
在介绍透明导电薄膜光学性质的基础上,分别讨论了不同情况下,太阳能平板集热器盖板采用镀有透明导电薄膜的玻璃对集热器的光热转换效率和保温性能的影响。结果表明,当集热器吸热板表面没有覆盖选择性吸收涂层,在盖板玻璃下表面镀有透明导电薄膜可以在一定温度范围内提高集热器的转换效率和保温性能,而当吸热板已覆盖有选择性吸收涂层时,盖板玻璃再镀透明导电薄膜,集热器辐射热损则减少很少,甚至不足以补偿由于玻璃透过率降低而增加的光反射损失,在这种情况下,盖板不宜再采用镀有透明导电薄膜的玻璃。 相似文献
5.
非木材纸浆的无元素氯漂白与二氧化氯制备系统的国产化 总被引:4,自引:3,他引:1
介绍了非木材纸浆ECF和TCF漂白的发展现状和发展前景,并对比ECF和TCF漂白工艺,得出ECF漂白更适合非木材纸浆.提出实现制备二氧化氯设备的国产化已成为迫在眉睫的事情. 相似文献
6.
薄膜体声波谐振器(FBAR)的谐振频率会受外界环境温度的影响而产生漂移,对于FBAR滤波器而言,这种温度-频率漂移特性会导致其中心频率、插入损耗、带内纹波等性能发生变化,降低其在电学应用中的可靠性。应用ANSYS有限元分析软件,对一个典型Mo-AlN-Mo结构的FBAR进行温度-频率漂移特性的仿真,在-50+150℃温度范围内得到其温度频率系数为-33.6×10-6/℃。通过在FBAR结构中添加一层正温度系数的补偿层,分析了补偿层厚度对FBAR温度-频率漂移特性、谐振频率和机电耦合特性的影响。设计的温度补偿FBAR其温度频率系数为0.872×10-6/℃,比未添加补偿层时有很大改善。 相似文献
7.
Carlos Vila Valentín Santos Juan Carlos Paraj 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(10):1098-1104
Beech wood samples subjected to pulping in HCl‐catalysed acetic acid media (Acetosolv process) under selected conditions were bleached using several Totally Chlorine Free (TCF) sequences including peracetic acid (Paa), alkaline (E), oxygen (O), chelating (Q) and peroxide (P) treatments. PaaEQPP sequences starting from acetic acid media led to pulps with poor brightness, which was improved when the same sequence was carried out starting from aqueous media. An EOQPP sequence led to a pulp with acceptable properties, which were improved by a optimised EOQPaaP sequence, in which a fully bleached pulp was obtained at a SCAN viscosity of 604 cm3 g?1. EOQPaaP‐bleached pulp was explored for carboxymethyl cellulose (CMC) manufacture employing heterogeneous conditions in isopropanol media, and a CMC with a degree of substitution of 1.16 was obtained. Copyright © 2004 Society of Chemical Industry 相似文献
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In this study, a kinetic model of the final bleaching stage with hydrogen peroxide in a totally chlorine free (TCF) bleaching sequence for ALCELL® processed pulp was developed. The model was based on the rate of chromophore destruction characterized by the decrease in the light absorption coefficient of bleached pulp at 457 nm, CK. Based on the fact that the chromophore destruction proceeds rapidly in an initial phase followed by a much slower reaction during which a “floor-level” chromophore concentration is approached asymptotically, we propose that the hydrogen peroxide stage of the ALCELL® derived pulp in the studied TCF sequence consists of two distinct phases. The initial phase is a very fast reaction. The rate equation of the second phase was determined as: which is valid in a pH range of 10.5 to 11.5 and a temperature range of 60 to 92.5°C. 相似文献
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