Encapsulation of Perchlorate Salts within Metal Oxides for Application as Nanoenergetic Oxidizers

In this work, high‐oxygen‐content strong oxidizer perchlorate salts were successfully incorporated into current nanothermite composite formulations. The perchlorates were encapsulated within mild oxidizer particles through a series of thermal decomposition, melting, phase segregation, and recrystallization processes, which occurred within confined aerosol droplets. This approach enables the use of hygroscopic materials by stabilizing them within a matrix. Several samples, including Fe₂O₃/KClO₄, CuO/KClO₄ and Fe₂O₃/NH₄ClO₄ composite oxidizer particles, have been created. The results show that these composite systems significantly outperform the single metal oxide system in both pressurization rate and peak pressure. The ignition temperatures for these mixtures are significantly lower than those of the metal oxides alone, and time‐resolved mass spectrometry shows that O₂ release from the oxidizer also occurs at a lower temperature and with high flux. The results are consistent with O₂ release being the controlling factor in determining the ignition temperature. High‐speed imaging clearly shows a much more violent reaction. The results suggest that a strategy of encapsulating a very strong oxidizer, which may not be environmentally compatible, within a more stable weak oxidizer offers the opportunity to both tune reactivity and employ materials that previously could not be considered.     

基于试验数据的焊缝试样C*参量估算

针对焊缝和母材蠕变性能不相同的带焊缝CT试样,提出了一个等效均质材料模型,建立了焊缝中心裂纹、焊缝界面裂纹和非对称焊缝裂纹情况下由试验数据确定C*参量的修正式。采用ABAQUS软件进行了带焊缝CT试样C*参量的有限元分析。有限元数值解与修正式的预测值比较表明：与均质材料CT试样相比,低匹配焊缝会导致CT试样的hw因子增大,高匹配焊缝会导致hw因子值降低,采用ASTM E1457提供的公式在低匹配情况下会过低估算C*参量,在高匹配情况下会过高估算C*参量。无论是低匹配(M<1)焊缝还是高匹配(M >1)焊缝,修正后CT试样的C*参量计算式都可给出与有限元解非常接近的估算结果,可用于焊缝蠕变裂纹行为预测。     

Stability assessment of tunnel slopes along the Dujiangyan City to Siguniang Mountain Railway,China

This work focuses on integrated stability assessment of rocky tunnel slopes along a planned railway, namely, the Dujiangyan City to Siguniang Mountain Railway (DS Railway), which is an important transportation corridor in Southwest China. Investigating the stability of slopes at the entrances and exits of tunnels represents the first step of railway construction. Based on detailed geological engineering studies, the stability of 32 tunnel slopes was measured and evaluated by means of the slope mass rating (SMR), Chinese slope mass rating (CSMR) and Chinese continuous slope mass rating (CCSMR) systems. Moreover, a kinematic analysis technique was also employed to identify the potential failure modes of the jointed rock masses in tunnel slopes. The results reveal that the CSMR, by considering the slope height and discontinuity condition coefficient, can more robustly assess the slope stability than the SMR. Similarly, the CCSMR, which is based on continuous functions and can identify potentially dangerous slopes that should be reinforced, can reduce subjectivity. Many slopes deemed unstable and completely unstable by the CSMR and CCSMR are located on the banks of the river from Longchi to Longtan and from Xindianzi to Siguniang Mountain. The potential failure modes of the 32 slopes determined by kinematic analysis are basically consistent with the results obtained by the slope mass classification systems. These research results pave the way for stability assessment and intervention decision-making during the construction of the DS Railway.

     

公路施工技术及道路路面施工质量控制对策研究

提高公路工程施工质量是人们不断的追求和目标。文章介绍了公路路基、路面施工技术,指出了道路路面施工质量控制的意义,并提出相应的质量控制对策。     

转换层超重钢桁架高空吊装施工技术

某工程酒店部分采用钢结构与混凝土相结合的劲性结构,在4层标高14.650m设备层处开始为超重钢转换桁架.整个劲性钢筋混凝土转换桁架跨度36m,单节钢梁最大重量为23.6t,钢结构安装位置超出了塔吊起吊范围.项目部通过技术攻关,采用50 t吊车吊装到设计标高,铺设槽钢枕木轨道,利用滑轮组和塔吊安装就位的创新施工技术,成功地解决了起重转换桁架的高空吊装难题,确保了主体结构施工安全顺利进行.     

Reversible pH manipulation of the fluorescence emission from sectorial poly(amido amine) dendrimers

The first to fourth generation (G1-G4) of sectorial poly(amido amine) (PAMAM) dendrimers with ethanolamine core and amino terminals are synthesized by a divergent route. Blue fluorescence emission from these dendrimers is observed. It is found that there is a remarkable difference in the fluorescence behavior for these different generations of dendrimers. The emission intensity of these dendrimers is almost linearly enhanced along with the increase of their concentrations. A significant pH-dependent profile of the fluorescence intensity is also observed. As the pH value decreases from 8 to 3, the fluorescence intensity increases almost linearly. Furthermore, the fluorescence intensity of the dendrimers shows a reversible behavior depending on pH value within the pH range from 3 to 11. This property enables the reversible manipulation of the fluorescence of these dendrimers by adjusting the pH values, which contributes to a potential application of these materials in fluorescent pH sensors.     

Advanced Composite Solid Electrolytes for Lithium Batteries: Filler Dimensional Design and Ion Path Optimization

Composite solid electrolytes are considered to be the crucial components of all-solid-state lithium batteries, which are viewed as the next-generation energy storage devices for high energy density and long working life. Numerous studies have shown that fillers in composite solid electrolytes can effectively improve the ion-transport behavior, the essence of which lies in the optimization of the ion-transport path in the electrolyte. The performance is closely related to the structure of the fillers and the interaction between fillers and other electrolyte components including polymer matrices and lithium salts. In this review, the dimensional design of fillers in advanced composite solid electrolytes involving 0D–2D nanofillers, and 3D continuous frameworks are focused on. The ion-transport mechanism and the interaction between fillers and other electrolyte components are highlighted. In addition, sandwich-structured composite solid electrolytes with fillers are also discussed. Strategies for the design of composite solid electrolytes with high room temperature ionic conductivity are summarized, aiming to assist target-oriented research for high-performance composite solid electrolytes.     

Optimization of multi-tag identification for UHF RFID multi-antenna tag readers

针对现有的超高频(UHF)射频识别(RFID)标签阅读器使用单个天线,难以保证多标签识别可靠性的问题,提出了一种通过增加天线个数,以增强覆盖效果、减少识别盲区、增强多标签识别可靠性的RFID多天线识别模式,并利用遗传算法对识别过程中启用天线的个数进行优化,通过合理处理选择、交叉、变异遗传算子以提高RFID阅读器多标签识别的可靠性.实验结果表明:增加天线个数可以增强覆盖效果、减少识别盲区;基于遗传算法的识别优化算法具有良好的搜索性和收敛性,提高了系统识别的可靠性.该研究为复杂环境下应用超高频RFID技术提供了新思路.     

透明导电InSnGaMo氧化物薄膜光电性能研究

利用脉冲激光沉积法在石英衬底上制备出了可见光透过率高、电阻率极低的Ga,Mo共掺杂ITO基InSnGaMo复合氧化物薄膜。研究了衬底温度对薄膜结构、表面形貌、光电性能的影响。实验结果表明:衬底温度对InSnGaMo复合氧化物薄膜形貌、光电性能均有很大影响。X射线衍射、扫描电镜和霍尔测试结果表明,随着衬底温度的升高,薄膜晶粒度增大,电阻率快速下降,可见光平均透过率明显提高。当衬底温度为450℃时,InSnGaMo复合氧化物薄膜的电阻率最低为4.15×10-4Ω.cm,载流子浓度和迁移率最大分别为3×1020cm-3,45 cm2V-1s-1,在可见及近红外区平均透过率达92%,特别地,波长为362 nm时,最高透射率可达99%。     

TiAlN涂层材料的制备及性能研究

采用独立靶材在YG6硬质合金上以电弧离子镀工艺制备了TiAlN涂层,研究了钛靶弧流对涂层的微观形貌、成分和性能的影响,对TiAlN涂层的膜基结合强度及高温抗氧化性能进行了测试分析,并将TiAlN涂层的YG6硬质合金刀具与未涂层的YG6硬质合金刀具对T12工模具钢(50HRC)进行对比切削试验。结果表明:钛靶弧流为60～70A时,涂层具有较理想的表面结构,膜基结合力较好,可达44N;钛靶电流对涂层中N含量的影响不大,对Al及Ti含量有较明显的影响。在干式切削条件下,TiAlN涂层刀具的使用寿命是未涂层刀具的3倍。