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排序方式: 共有2501条查询结果,搜索用时 15 毫秒
1.
Teng Zheng Laihui Luo Peng Du Anmeng Deng Weiping Li 《Journal of the European Ceramic Society》2018,38(2):575-583
The (0.98-x)(0.6Pb(Mg1/3Nb1/3)O3-0.4PbTiO3)-xPb(Yb1/3Nb1/3)O3-0.02Pb(Er1/2Nb1/2)O3 ((0.98-x)(PMN-PT)-xPYN:Er3+) ceramics were prepared through a solid-state reaction method. The phase structure, piezoelectric response, ferroelectric performance and upconversion emission of the ceramics were systematically investigated. The phase structure, the electrical and optical properties are strongly related to the content of PYN. The optimized piezoelectric response and upconversion emissions of the ceramics were achieved near x = 0.12, which locates in the morphotropic phase boundary (MPB) composition. Furthermore, the temperature sensing behaviors of the resultant compounds based on the thermally coupled levels of 2H11/2 and 4S3/2 of Er3+ ions in the temperature range of 133–573 K were studied by utilizing the fluorescence intensity ratio technique. Additionally, the thermal effect, which is induced by the laser pump power, of the studied ceramics is also investigated and the produced temperature is enhanced from 268 to 348 K with the pump power rising from 109 to 607 mW. 相似文献
2.
本文分析了燃气热水器行业针对无回水管水路系统实现零冷水功能的现有技术方案,指出现有技术方案存在的一些缺陷,并结合试验研究,对无回水管水路系统提出了一套全新的实现零冷水功能的技术解决方案。 相似文献
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A balcony wall type solar water heater system was designed and constructed in a high-rise building. The U-type evacuated glass tube solar collector is fixed vertically on the balcony wall. The water, heated in the solar collector, flows through the exchanger coil in the water tank and then flows back to the solar collector. With regard to the hot water supply system, the cold water, heated by the heat exchanger, is sent to the point of use. Considering storeys and water consumption pattern, four apartments are selected for testing. Meanwhile, the theoretical analysis with TRNSYS was presented. According to the experimental results, mean daily collector efficiency is about 40%. Solar fraction is high in summer and autumn for the relative high radiation and high ambient temperature. Under given conditions, the annual energy extracted from tank is 2805.3 MJ/m2, and the annual solar fraction is 40.5%. When the tank volume-to-collector area ratio is decreased to 37.5 L/m2, the solar fraction can be increased to 50%. The results show that the family to use water all day round gets higher solar fraction than the family using hot water mostly in the morning and night. 相似文献
5.
《Advanced Powder Technology》2020,31(3):1023-1031
We investigated the effects of different metal oxide (MO) nanoparticles (e.g., CuO, KIO4, Fe2O3) on the combustion and gas-generating characteristics of sodium azide microparticle (NaN3 MP; gas-generating agent) and aluminum nanoparticle (Al NP; heat source) composite powders. The NaN3 MP/Al NP/MO NP composite powders were stably ignited using a microhotplate (MHP) heater. The addition of CuO and KIO4 to the NaN3 MP/Al NP composite powders resulted in relatively high burn rates and high pressurization rates upon MHP-assisted ignition. This suggests that the highly reactive CuO and KIO4 NPs significantly increased the combustion of the Al NPs; as a result, sufficient heat energy was generated via the active aluminothermic reaction to thermally decompose the NaN3 MPs. Finally, the gas generating properties of NaN3 MP/Al NP composite powders mixed with various MO NPs were tested using homemade inflatable small airbags. The airbags were fully inflated within ~20 ms when CuO and KIO4 NPs were added to the NaN3 MP/Al NP composite powders. However, the addition of Fe2O3 NPs to the NaN3 MP/Al NP composite powder resulted in a slow and only partial inflation of the airbag due to an incomplete aluminothermic reaction, which was due to a slow combustion reaction between the Al NPs and relatively weak oxidizer of the Fe2O3 NPs. This suggests that the rapid, stable, and complete thermal decomposition of NaN3 MP/Al NP composites can be effectively achieved by employing highly reactive nanoscale oxidizers. 相似文献
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Sivarathinamoorthy Haldorai Sureshkannan Gurusamy Maruthaiyan Pradhapraj 《国际能源研究杂志》2019,43(12):6061-6077
The drying needs of agricultural, industrial process heat requirements and for space heating, solar energy is one of the prime sources which is renewable and pollution free. As the solar energy is inconsistent and nature dependent, more often there is a mismatch between the solar thermal energy availability and requirement. This drawback could be addressed to an extent with the help of thermal energy storage systems combined with solar air heaters. This review article focuses on solar air heaters with integrated and separate thermal energy storage systems as well as greenhouses with thermal storage units. A comprehensive study was carried out in solar thermal storage units consisting of sensible heat storage materials and latent heat storage materials. As the phase change heat storage materials offer many advantages over the sensible heat storage materials, the researchers are more interested in this system. The charging and discharging characteristics of thermal storage materials with various operational parameters have been reported. All the possible solar air heater applications with storage units have also been discussed. 相似文献
8.
A low‐carbon electricity supply for Australia was simulated, and the installed capacity of the electrical grid was optimized by shifting the electricity demand of residential electric water heaters (EWHs). The load‐shifting potential of Australia was estimated for each hour of the simulation period using a nationwide aggregate EWH load model on a 90 × 110 raster grid. The electricity demand of water heaters was shifted from periods of low renewable resource and high demand to periods of high renewable resource and low demand, enabling us to effectively reduce the installed capacity requirements of a 100%‐renewable electricity grid. It was found that by shifting the EWH load by just 1 hour, the electricity demand of Australia could be met using purely renewable electricity at an installed capacity of 145 GW with a capacity factor of 30%, an electricity spillage of 20%, and a generation cost of 15.2 ¢/kWh. A breakdown of the primary energy sources used in our scenario is as follows: 43% wind, 29% concentrated solar thermal power, and 20% utility photovoltaic. Sensitivity analysis suggested that further reduction in installed capacity is possible by increasing the load‐shifting duration as well as the volume and insulation level of the EWH tank. 相似文献
9.
分析了一例哈尔滨汽轮机厂汽轮机3#高加加热器疏水液位高、正常疏水管路振动的原因,针对类似情况,从高加疏水系统设备结构、系统运行方式等方面提出了相应的解决措施,解决了疏水管路的振动,保证了机组安全经济运行.并对另一例哈尔滨汽轮机厂600 MW机组轴封加热器水侧管束破裂,凝结水大量进入轴封加热器汽侧,满水后,进入轴封系统,进入汽轮机事故进行分析,提出轴封系统及其他系统如何进行排查,系统设置中存在类似的问题,采取相应措施进行整改的具体方法进行了介绍. 相似文献
10.
焦化加热炉的燃料消耗在焦化装置能耗中占有很大的比例,提高焦化炉的热效率,减少燃料消耗,能够达到加热炉节能减排的目的。通过降低焦化加热炉外壁温度减少炉体散热损失是已知有效地提高加热炉热效率方法之一,然而减少炉壁散热损失就意味着增加投资,那么炉壁温度降低到什么程度最为合理,以国内常用的典型焦化炉炉型和应用了较为先进的附墙燃烧技术的炉型为例,以这两种炉型常用的衬里材料为参考依据,通过计算几种不同外壁温度下两种炉型的散热量和衬里用量的变化,进行了相应的经济性计算分析,结果显示在现行设计标准的基础上降低炉墙外壁温度,可以有效减少散热损失,进而提高焦化炉热效率是可行的,在多个炉墙外壁温度的比选中,以三年投资回收期来看,60℃的外壁温度最为经济合理。 相似文献