TiO2-In-Nb2O5敏感材料响应TMA气敏特性分析

以含In的TiO2为基质,与重量比为10%的Nb2O5混合,TiO2-In-Nb2O5混合敏感材料有效解决了三甲胺(TMA)动物食品测鲜气敏器件中提高电导率和保持高灵敏度之间的矛盾.并利用XRD、SEM对该混晶体的结构、形貌及其机理进行分析,发现:该富钛混晶体中颗粒间的空隙增大、颗粒颈部变细,有效提高了响应TMA敏感特性;混合过程中所形成含铌的氧化态混晶体是缺氧态的,氧空位的增多有助于敏感材料电导率的增加.     

合金熔体过热处理的研究进展

熔体过热处理主要研究的是金属或合金熔体的结构和物理化学性质随熔体过热处理温度、时间及其在冷却和凝固过程中的变化规律.通过适当的熔体过热处理可以改善合金的组织和提高综合力学性能.系统介绍了合金熔体过热处理工艺国内外的研究现状,探讨了今后的发展方向.     

Tc动能弹侵彻陶瓷复合靶的仿真与试验研究

在14.5 mm制式弹弹头部采用非金属Tc材料,并与制式弹进行对比,在相同装药量的情况下,试验研究了两种弹丸对陶瓷复合靶的侵彻能力。采用ANSYS-LS/DYNA进行模拟仿真,并与试验结果对比,模拟结果与试验结果基本吻合,Tc复合弹侵彻装甲钢板形成冲塞,并在装甲钢背面有鼓包,鼓包周围有明显的裂纹。结果表明,Tc复合弹对陶瓷/钢复合靶的侵彻能力优于制式弹。     

多状态影响下基于Bi⁃LSTM网络的锂电池剩余寿命预测方法

现有基于深度学习的锂电池剩余寿命(Remaining Useful Life,RUL)预测方法中,锂电池多个内部状态所蕴含的寿命信息未得到充分考虑.鉴于此,提出了一种融合电池容量、阻抗与温度三个内部状态的RUL预测模型.首先,引入双向长短时记忆(Bi?directional Long Short?Term Memory...     

Potential of performance improvement of concentrated solar power plants by optimizing the parabolic trough receiver

This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations. The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers. The annual electricity productions of power plants with novel receivers in Phoenix, Sevilla, and Tuotuohe are 8.5%, 10.5%, and 14.4% higher than those with traditional receivers at the outlet temperature of 550°C. The levelized cost of electricity of power plants with double-selective-coated receivers can be decreased by 6.9%, 8.5%, and 11.6%. In Phoenix, the optimal operating temperature of the power plants is improved from 500°C to 560°C by employing a novel receiver. Furthermore, the sensitivity analysis of the receiver heat loss, solar absorption, and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance. Solar absorption has a positive contribution to annual electricity productions, whereas heat loss and freeze protection temperature have a negative effect on electricity outputs. The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants.     

A spectrally selective surface structure for combined photothermic conversion and radiative sky cooling

The sun and outer space are the ultimate heat and cold sources for the earth, respectively. They have significant potential for renewable energy harvesting. In this paper, a spectrally selective surface structure that has a planar polydimethylsiloxane layer covering a solar absorber is conceptually proposed and optically designed for the combination of photothermic conversion (PT) and nighttime radiative sky cooling (RC). An optical simulation is conducted whose result shows that the designed surface structure (i.e., PT-RC surface structure) has a strong solar absorption coefficient of 0.92 and simultaneously emits as a mid-infrared spectral-selective emitter with an average emissivity of 0.84 within the atmospheric window. A thermal analysis prediction reveals that the designed PT-RC surface structure can be heated to 79.1°C higher than the ambient temperature in the daytime and passively cooled below the ambient temperature of approximately 10°C in the nighttime, indicating that the designed PT-RC surface structure has the potential for integrated PT conversion and nighttime RC utilization.     

模糊控制的模糊推理分析

分析了使用RZ算子时推理合成规则(CRI)不具有还原性和不能正确进行模糊推理的原因,给出了正确应用CRI的条件;分析了全蕴涵3I算法的不足及其具有还原性的原因;对各种蕴涵算子的模糊推理进行分析比较,得到了正确的推理算法;对模糊推理在理论和实际应用中的矛盾作了具体说明.     

高压条件下石英砂中的静力触探试验及大变形模拟

在深部土层中进行原位试验时,以往针对中低应力水平的数据解译公式不再适用。为探究砂土在高应力条件下的力学特性,利用自行研制的高压标定罐,改变围压水平,进行不同密实度石英砂中的静力触探试验,基于任意拉格朗日—欧拉格式的大变形有限元方法,模拟静力触探仪的完整贯入过程,有效避免了锥尖周围的网格扭曲。大变形模拟中采用修正摩尔—库伦模型描述砂土的内摩擦角和剪胀角随累积塑性剪应变的变化,并通过修正弯曲元试验,确定合理的土体剪切模量。标定罐试验和大变形有限元方法获得的锥尖阻力结果能很好地相互验证;在此基础上,建立高应力条件下静力触探锥尖阻力与砂土相对密实度之间的关系,与已有的低应力水平试验结果进行对比,证明建立的经验公式能通过锥尖阻力很好地预测砂土的相对密实度。     

碲化物玻璃在光纤光学中的应用及研究进展

碲化物玻璃(TeO2)作为一种稳定的玻璃形态,近年来受到人们的关注。文中首先将碲化物玻璃的一些特性与石英玻璃等玻璃材料进行了对比,然后介绍了它在光纤设备制造方面的应用,最后回顾了近年来这方面的研究进展。     

改进RetinaNet的水泥路面露骨病害检测

露骨病害是水泥路面常见的病害之一,会严重影响路面使用年限和行车安全性能.因此,及时对露骨病害进行检测与修复十分重要.针对传统的人工检测方法检测精度不高且检测效率低的问题,本文提出一种基于改进RetinaNet模型的水泥路面露骨病害检测方法.首先对人工和检测车采集露骨病害图像进行滤波、去噪等预处理操作,构建模型训练数据集...