An excellent universal catalyst support-mesoporous silica: Preparation,modification and applications in energy-related reactions

As a kind of versatile, excellent catalyst carriers, mesoporous silicas (mSiO₂) have been widely applied for preparing various supported catalysts with ideal catalytic properties due to their uniform and regular channels, adjustable medium pore size, big surface area, controllable wall composition, high hydrothermal stability, easy functional modification and good accessibility of larger reactant molecules. mSiO₂ not only enhances the dispersity of the active phase and generates more active sites for superior catalytic activity but also improves resulted selectivity and cyclic lifespan for enhanced interaction. And high adsorption capacity of mSiO₂ also increases the reactant molecule enrichment. In addition, mesoporous feature of the mSiO₂ pore wall can ensure diffusion of the substrate molecules and prevent leaching of active components. Thus, related investigation and application have been rapidly growing in the past decades. In this review, the development of mesoporous silica based catalysts on preparation, modification, pore size tune and energy-related applications, especially in hydrogenation reaction, esterification reaction, hydrogen production by alkane dry reforming and alcohol steam reforming and photocatalytic water splitting, is introduced in detail and the design ideas, preparation strategies and corresponding mechanism of different composite catalysts are discussed.     

A novel fusion paradigm for multi-channel image denoising

Multi-channel and single-channel image denoising are on two important development fronts. Integrating multi-channel and single-channel image denoisers for further improvement is a valuable research direction. A natural assumption is that using more useful information is helpful to the output results. In this paper, a novel multi-channel and single-channel fusion paradigm (MSF) is proposed. The proposed MSF works by fusing the estimates of a multi-channel image denoiser and a single-channel image denoiser. The performance of recent multi-channel image denoising methods involved in the proposed MSF can be further improved at low additional time-consuming cost. Specifically, the validity principle of the proposed MSF is that the fused single-channel image denoiser can produce auxiliary estimate for the involved multi-channel image denoiser in a designed underdetermined transform domain. Based on the underdetermined transformation, we create a corresponding orthogonal transformation for fusion and better restore the multi-channel images. The quantitative and visual comparison results demonstrate that the proposed MSF can be effectively applied to several state-of-the-art multi-channel image denoising methods.     

Mechanically induced rhombohedral to tetragonal phase transition in PMN–PT single crystals by nanoindentation

Understanding the phase transition behavior of the rhombohedral phase (R) and tetragonal phase (T) of the relaxor ferroelectric PMN–PT single crystals under mechanical load is essential for the potential voltage-free controlled ferroelectric-based nanodevices. Relaxor ferroelectric single crystals PMN–PT, under a local inhomogeneous mechanical load, were studied experimentally by the nanoindentation tests and Raman spectroscopy measurements. The observations show that the rhombohedral phase can be transformed successfully to the tetragonal phase under a mechanical stress, and the tetragonal phase in the PMN–PT single crystals presents a structural stability. The phase transition induced by the mechanical stress with different strain rates further indicates that the relaxor ferroelectric single crystals possess a potential mechanical controllability. The present study reveals the phase transition pathway of the relaxor ferroelectric single crystal under inhomogeneous stress and provides the exciting possibility of the control of mechanically induced phase transition for ferroelectrics.     

石英块料直接煅烧法生产方石英

阐述了石英块料直接煅烧法生产加工方石英的工艺特点。产品通过X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)测试,说明块料直接煅烧法生产的方石英具有转化率高、加工性能好、成本低等特点。     

高岭土露天矿技改设计中运输系统的选择

介绍了龙岩高岭土公司矿石和废石运输的原设计方案、生产现状和技改设计中须解决的问题。根据矿山的实际情况,推荐了矿石和废石运输的可行方案,并阐述了它们的优缺点。同时,从工艺技术、征地、基建投资、运行费用等技术经济方面分别对可行的矿石和废石运输系统进行了详细的比较。最终确定,公路-胶带联合运输和公路运输分别为矿石和废石运输的最佳方案。     

治理小井漏风的技术措施

东一采区二段风道小井漏风严重影响了采煤工作面的接续,制约采区巷道维修。采取系统改造,结合堵漏的方法,解决了小井漏风问题。     

提高风机系统节能改造的途径

风机在全国数量众多,分布面广,耗电量巨大,因此风机节能具有巨大的经济意义,风机的节能改造包括风机的更新与改造两方面,介绍了更新的方式和改造的几个方面,指出变速调节方式是一种高效的调节方式,节能效果相对最好。     

锡和铅-锡合金相变点附近导热系数的测定

应用利用相界面移动速率曲线测量物质熔点温度附近固、液相热物性的方法。采用电加热器取代恒温浴。通过改进定解条件和采用新的数值计算方法。实验测量锡与铅一锡合金的导热系数。结果与文献报道数据吻合，测量误差约为5％。测试过程中不要求瞬间温度突变的边界条件。从而确保了测试过程中被测试材料的晶型、结构和热物理性能的稳定性，保证了测试结果的真实性。