内插式真空管太阳能热水器热特性理论及实验研究

设计了一种内插式真空管热水集热器,通过对其能量转换、传输特性研究,建立了内插式真空管集热器的热特性分析模型,并对不同设计参数和气候条件对内插式真空管热特性的影响进行了分析。结果表明,设计的集热器理论热效率最大可达79.5%,但其受环境温度、集热器工作温度等影响较大。此外,设计了由14只内插式真空管组成的太阳能热水器,采用迟滞算法将热水温度控制在50～55℃,实验结果表明,样机系统的日热效率可达55.0%,样机输出热水近120 kg,具有较好的实用价值。     

寒冷地区用空气源热泵热水器准双级压缩循环特性研究

空气源热泵热水器在寒冷地区运行时会出现排气温度过高、制热性能弱等弊端,准双级压缩循环技术可有效改善其在寒冷地区的运行特性。采用带中压补气的转子压缩机,研制了以R410A为循环工质的空气源热泵热水器,试验研究了系统在寒冷地区低温环境下的制热性能。结果表明:带中压补气的空气源热泵热水器系统排气温度较无补气有所降低,当室外温度从7.0下降到-25.0℃时,与无补气系统相比,补气系统制热量提升了6.2%～15.5%,压缩机功率提升了2.8%～9.5%,COP_h提升了3.3%～9.6%。     

Ferroelectric,upconversion emission and optical thermometric properties of color-controllable Er3+-doped Pb(Mg1/3Nb2/3)O3-PbTiO3-Pb(Yb1/2Nb1/2)O3 ferroelectrics

The (0.98-x)(0.6Pb(Mg_1/3Nb_1/3)O₃-0.4PbTiO₃)-xPb(Yb_1/3Nb_1/3)O₃-0.02Pb(Er_1/2Nb_1/2)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 ²H_11/2 and ⁴S_3/2 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.     

现代镀覆技术 第二部分──化学镀镍(续4)

给出了各种实用的化学镀镍配方及其工艺条件。     

燃气热水器在无回水管水路中实现零冷水的方案研究

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。     

Effects of metal oxide nanoparticles on combustion and gas-generating performance of NaN3/Al composite powders ignited using a microhotplate platform

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.     

余热锅炉高温过热器直管段材质分析鉴定

采用化学成分分析、力学性能测试以及金相检验等手段对某余热锅炉未出现泄漏的高温过热器管直管段进行了材质分析鉴定.结果表明:1号试样取样部位附近的管子不符合GB 13296-2007的要求,不可继续使用,须更换;2号试样取样部位附近的管子基本符合标准要求,可以监督运行,并定期抽检材质的变化情况,建议更换.     

燃气快速热水器有害物排放及其对厨房环境污染的试验研究

利用燃气快速热水器在不同使用工况下，烟气中有害气体含量及厨房环境测试数据，分析了热水器排放及其对厨房环境的污染情况。通过分析得出结论，提醒人们在使用热水器时应注意的问题。模拟工况有以下几种：厨房空气流通情况下热水器正常使用；厨房空气不流通情况下使用热水器；厨房空气流通情况下，热水器烟道部分堵塞；厨房空气不流通情况下，热水器烟道部分堵塞。     

水流量传感器在燃气热水器的应用

分析了水流量传感器的工作原理,将水流量传感器与压差式水气联动阀进行比较.