Fractional-order anisotropic diffusion for image denoising.

This paper introduces a new class of fractional-order anisotropic diffusion equations for noise removal. These equations are Euler-Lagrange equations of a cost functional which is an increasing function of the absolute value of the fractional derivative of the image intensity function, so the proposed equations can be seen as generalizations of second-order and fourth-order anisotropic diffusion equations. We use the discrete Fourier transform to implement the numerical algorithm and give an iterative scheme in the frequency domain. It is one important aspect of the algorithm that it considers the input image as a periodic image. To overcome this problem, we use a folded algorithm by extending the image symmetrically about its borders. Finally, we list various numerical results on denoising real images. Experiments show that the proposed fractional-order anisotropic diffusion equations yield good visual effects and better signal-to-noise ratio.     

Self-powered photoelectrochemical biosensing platform based on Au NPs@ZnO nanorods array

Photoanodes, which are used in photoelectrochemical (PEC) water splitting, have been shown to be applicable in the construction of a PEC biosensing platform. This was realized by replacing water oxidization with oxidation of an appropriate test molecule. Here, we have demonstrated the feasibility of adopting photoanodes consisting of zinc oxide nanorods arrays decorated with plasmonic gold nanoparticles (Au NPs@ZnO NRs) for the self-powered PEC bioanalysis of glutathione (GSH) in phosphate-buffered saline (PBS) at an applied bias potential of 0 V vs. Ag/AgCl. This heterostructure exhibited enhanced PEC properties because of the introduction of the Au/ZnO interface. Under visible light illumination, hot electrons from surface-plasmon resonance (SPR) at the Au NP surface were injected into the adjacent ZnO and subsequently driven to the photocathode. Under ultraviolet (UV) light illumination, the photogenerated electrons in ZnO tended to transfer to the fluorine-doped tin oxide due to the step-wise energy band structure and the upward energy band bending at the ZnO/ electrolyte interface. These results indicate that plasmonic metal/semiconductor heterostructure photoanodes have great potential for self-powered PEC bioanalysis applications and extended field of other photovoltaic beacons.

Open image in new window

     

MoS<Subscript>2</Subscript> yolk–shell microspheres with a hierarchical porous structure for efficient hydrogen evolution

Yolk–shell architectures have attracted extensive attention owing to their unique structure and infusive applications. MoS₂ is regarded as one of the most promising catalytic materials for hydrogen evolution by the splitting of water. In this work, a simple self-template solvothermal approach is developed for the synthesis of novel MoS₂ yolk–shell microspheres with a hierarchical porous structure by reacting MoO₂ microspheres with L-cysteine. A dissolutionrecrystallization formation mechanism is proposed for the MoS₂ yolk–shell microspheres. Owing to structural superiority, the new material architecture exhibits improved photoelectrochemical properties, including efficient hydrogen evolution reaction catalytic activities, a high photocurrent density, a small overpotential, and a low charge-transfer resistance.

Open image in new window

     

Structural Formation and Improved Performances of Chemically Synthesized Composition-Controlled Micron-Sized Fe100−x Co x Particles

Micron-sized composition-controlled Fe_100?x Co _x (20 < x < 75) alloy particles with high purity have been prepared by an optimized reduction reaction. The influence of Co content on the alloying process, structures, and magnetic properties of the products has been studied. The as-synthesized Fe_{100 ?x} Co _x with x < 65 exhibit a single bcc crystal structure. A bcc-FeCo/fcc-Co composite structure can be formed in the Fe_100?x Co _x products with x > 65. Very slight surface oxidation is observed in all the products. The high purity and single bcc-FeCo phase for the well-alloyed Fe_{100 ?x} Co _x particles with x < 65 lead to their high saturation magnetization of 182–220 A m² kg^?1. All the well-alloyed Fe_{100 ?x} Co _x show nearly spherical morphologies with an average particle size of 2–8 μm, which results in their good compactibility with a high compacted density of about 7.4–7.6 g cm^?3. The simple preparation and improved performances for these chemically synthesized composition-controlled FeCo particles show their great potential for applications in near-net-shaped and complex-shaped FeCo-based soft magnetic composite devices.     

磷铁真空蒸馏行为分析研究

为了了解磷铁在真空蒸馏过程中的物相变化规律,本文通过热力学计算,得到磷铁在压力为10~10~5Pa下的化学反应吉布斯自由能和分解反应温度的关系。计算表明磷铁的分解反应主要分三个阶段:(1209~1350 K)FeP生成Fe、Fe_3P和P_2;(1350~1693 K)主要是Fe_2P发生分解生成P_2、Fe_3P和Fe;当温度高于1693 K时,Fe_3P开始分解生成P_2和Fe。并在1373,1473,1573,1673 K等温度条件下,恒温60 min,对磷铁进行了真空蒸馏实验,考察其残渣物相及元素含量变化。结果表明,当温度由1373升高到1673 K时,磷不断减少,由16.3%降到了10.75%,磷铁物相变化为FeP→Fe_2P-Fe_3P→Fe,与热力学计算结果相符。实验证明,可以通过真空蒸馏的方法回收磷铁副产中的磷。     

Informative patches sampling for image classification by utilizing bottom-up and top-down information

In image classification based on bag of visual words framework, image patches used for creating image representations affect the classification performance significantly. However, currently, patches are sampled mainly based on processing low-level image information or just extracted regularly or randomly. These methods are not effective, because patches extracted through these approaches are not necessarily discriminative for image categorization. In this paper, we propose to utilize both bottom-up information through processing low-level image information and top-down information through exploring statistical properties of training image grids to extract image patches. In the proposed work, an input image is divided into regular grids, each of which is evaluated based on its bottom-up information and/or top-down information. Subsequently, every grid is assigned a saliency value based on its evaluation result, so that a saliency map can be created for the image. Finally, patch sampling from the input image is performed on the basis of the obtained saliency map. Furthermore, we propose a method to fuse these two kinds of information. The proposed methods are evaluated on both object categories and scene categories. Experiment results demonstrate their effectiveness.     

三维地理信息系统在石油化工厂安全事故应急管理方面的实际应用

三维地理信息系统构建真实的石油化工厂三维虚拟场景,并以此为基础建立预案管理、资源管理、设备管理、实时监控管理、应急演练等安全事故应急管理相关应用,有助于工人全面掌握各类设备的综合状况,实现石化厂设备设施的动态化、精细化管理,有效地预防并避免重大事故的发生。     

关于卡明斯基仪测定毛细上升高度方法的讨论

针对卡明斯基仪测定毛细高度方法在应用中的一些问题,利用卡明斯基毛细仪原理。进行了测定毛细上升高度的试验,确定渗透速度与毛细高度的关系,以及对比不同粒径毛细高度达到稳定时渗透速度,结果表明,随着渗透速度的减小,毛细高度减小,减小到一定数值时,毛细高度趋于稳定;不同粒径毛细高度达到稳定时的渗透速度也不同。     

网状聚类算法在横河DCS故障分析系统中的应用

通过最小化目标函数分析研究,提出了网状聚类算法,阐述并实现了簇心全连通和簇心连通模型,同时以CENTUMCS3000 R3和V B的OCX控件为平台,开发了某化工厂爆炸监控系统。实践表明,聚类结果与监控设备运行结果吻合得很好,满足了化工厂监控系统的实际需求,证明该聚类算法和应用模型具有较高的理论和实用价值。     

煤基富勒烯电子性质和非线性光学性质的密度泛函理论研究

使用基于密度泛函理论的量子化学计算方法对煤基富勒烯进行了研究。重点关注由氮和硅掺杂C₆₀形成的杂化富勒烯结构。计算了这些杂化富勒烯的几何结构、稳定性、电子结构、介电常数和非线性光学性质并与未掺杂富勒烯相比较。研究发现,氮掺杂富勒烯失电子能力增强而硅掺杂富勒烯得电子能力增强。此外,根据计算结果可知掺杂可使富勒烯介电常数增大。对煤基富勒烯的非线性光学性质进行了探讨,发现氮掺杂富勒烯和硅掺杂富勒烯均具有比未掺杂富勒烯明显大的三阶非线性光学系数。