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91.
The multicaloric effect refers to the thermal response of a solid material driven by simultaneous or sequential application of more than one type of external field.For practical applications,the multicaloric effect is a potentially interesting strategy to improve the efficiency of refrigeration devices.Here,the state of the art in multi-field driven multicaloric effect is reviewed.The phenomenology and fundamental thermodynamics of the multicaloric effect are well established.A number of theoretical and experimental research approaches are covered.At present,the theoretical understanding of the multicaloric effect is thorough.However,due to the limitation of the current experimental technology,the experimental approach is still in progress.All these researches indicated that the thermal response and effective reversibility of multiferroic materials can be improved through multicaloric cycles to overcome the inherent limitations of the physical mechanisms behind single-field-induced caloric effects.Finally,the viewpoint of further developments is presented. 相似文献
92.
The vibration signal of gearboxes contains abundant fault information, which can be used for condition monitoring. However, vibration signal is ineffective for some non-structural failures. In order to resolve this dilemma, infrared thermal images are introduced to combine with vibration signals via fusion domain-adaptation convolutional neural network (FDACNN), which can diagnose both structural and non-structural failures under various working conditions. First, the measured raw signals are converted into frequency and squared envelope spectrum to characterize the health states of the gearbox. Second, the sequences of the frequency and squared envelope spectrum are arranged into two-dimensional format, which are combined with infrared thermal images to form fusion data. Finally, the adversarial network is introduced to realize the state recognition of structural and non-structural faults in the unlabeled target domain. An experiment of gearbox test rigs was used for effectiveness validation by measuring both vibration and infrared thermal images. The results suggest that the proposed FDACNN method performs best in cross-domain fault diagnosis of gearboxes via multi-source heterogeneous data compared with the other four methods. 相似文献
93.
94.
A novel method based on plastic processing and equipment for preparing ultra-fine metal fibers and particles is reported. With this new method, metal fibers and particles can both be produced on the same equipment and the surfaces of the fibers and particles can be protected from oxidation by the polymers or solvents during the preparation process. Metal-alloy powders with lower melt point were filled into polymer by an extruder, followed by a die-drawing process at a temperature lower than the melt temperature of the metal alloy. Metal fibers or particles were obtained after the polymer matrix was washed away. Metal alloy fibers can be obtained when a polymer that strongly interacts with metal alloy, such as a special polyvinyl alcohol with a low alcoholysis degree, is used as the polymer matrix. Metal-alloy particles can be obtained when a polymer with weak interaction with metal alloy, such as polyethylene (PE), is used as the polymer matrix. Based on the principle of this new method, it is possible to produce finer or even nano-sized metal fibers and particles with higher melting points. 相似文献
95.
半导体复合TiO2纳米光催化剂 总被引:12,自引:0,他引:12
对近年来利用半导体复合TiO2纳米光催化剂进行了介绍。总结了复合TiO2纳米光催化剂的制备、复合物的种类、光催化机理以及影响半导体复合TiO2光催化性能的因素。 相似文献
96.
97.
用热重分析法研究氢氧化镧的热分解过程 总被引:1,自引:0,他引:1
在研究固相交换反应过程中,我们对氢氧化镧进行了热重分析,发现氢氧化镧的热分解过程是分两步进行的,由其热重曲线计算了氢氧化镧热分解反应的活化能和反应级数。 相似文献
98.
Ir(Ⅳ)—KBrO3—DBS—偶氮氯膦催化分光光度法测定微量铱的研究 总被引:11,自引:1,他引:11
KBrO3-DBS偶氮氯膦在0.8ml.L^-1的H2SO4介质中长时间加热亦无明显褪色现象,但在有微量铱存在时,褪色反应在3min内完成,且与Ir(Ⅳ)的浓度有良好的线性关系,据此建立了微量铱的催化褪色分光光度分析法,其检出限为0.01μg.10mL^-1铱的含量在0.01-0.20μg.10mL^-1范围内符合比尔定律。 相似文献
99.
100.
氧化石墨的谱学表征及分析 总被引:1,自引:2,他引:1
采用改进的Hummers法,通过改变氧化剂用量获得不同氧化程度的氧化石墨,用X射线衍射(XRD)、红外光谱(FTIR)和拉曼光谱(Raman)对产物进行结构和谱学特性的表征,并结合数学分析软件对部分红外和拉曼数据进行分峰拟合。结果表明,石墨经氧化后形成了含有C-OH、-COOH和C-O-C等官能团的石墨层间化合物;氧化剂用量较少时,石墨片层插层氧化不完全,产物的结构中仍存在未被氧化的原石墨周期性结构;随着氧化剂用量的增加,氧化石墨产物的XRD图中原石墨(002)衍射峰逐渐消失,结构中含氧官能团的量逐渐增加,产物的亲水性也逐渐增强;通过对红外光谱的拟合发现,氧化石墨样品在3 198 cm-1附近有一个红外吸收峰,应归属于C-OH中OH的伸缩振动;随着氧化剂用量的增加,所得氧化石墨产物的拉曼光谱中D峰与G峰的强度积分比R(ID/IG)逐渐增大,产物结构中sp2平面域的平均尺寸逐渐减小。 相似文献