Fabrication of microporous and mesoporous carbon spheres for high‐performance supercapacitor electrode materials

Microporous and mesoporous carbon spheres (CSs) were fabricated using resorcinol and formaldehyde as precursors in the presence of Pluronic F127 as porogen and KOH as the active agent. The textural characteristic and morphology were characterized by scanning electron microscopy, transmission electron microscopy, and N₂ adsorption/desorption techniques. Pluronic F127 played an important role for generating mesopores, while KOH activation brought abundant micropores and resulted in a combined microporous and mesoporous structure of the CSs. The results showed that a typical sample (denoted as CS‐F‐K) possessed a spherical shape, with a high specific surface area of 735.4 m²/g, large pore volume of 0.622 cm³/g, and combined microporous and mesoporous structure, which endowed CS‐F‐K good electrochemical performance with a specific capacitance of 182 F/g under a current density of 0.5 A/g, remarkable rate performance, and long‐term cycling stability. After 1000 cycles at 3 A/g, CS‐F‐K electrode can still remain the specific capacitance of 154.8 F/g with a retention of 98.9%. The excellent electrochemical performance of CS‐F‐K was mainly attributed to the micro‐mesoporous structure, which promoted the ion accumulation on the electrode surface and facilitated fast ion transportation. Copyright © 2015 John Wiley & Sons, Ltd.     

d:x reflectance measurement for curved surface with integrating sphere

Ambient contrast ratio (ACR) is a useful parameter to evaluate the quality of displays when used under diffuse lighting conditions. The methodology recommended by most documentary standards calculates the ACR of the display from d:x reflectance. Reflectance measurement of flat surfaces typically employs an integrating sphere and a flat white reference plate. However, the shape difference between the flat white standard and test curved sample causes changes to the amount of light illuminating their surfaces and thus gives measurement errors. Especially for concave test surfaces, the error is significant when the sample has small radius of curvature. To increase the measurement accuracy, this paper derives the correction factor to compensate the effect caused by shape difference between the reference plate and test curved sample. The associated uncertainty analysis is also discussed in this paper.     

Model-based graph-cut method for automatic flower segmentation with spatial constraints

In this paper, we present an accelerated system for segmenting flower images based on graph-cut technique which formulates the segmentation problem as an energy function minimization. The contribution of this paper consists to propose an improvement of the classical used energy function, which is composed of a data-consistent term and a boundary term. For this, we integrate an additional data-consistent term based on the spatial prior and we add gradient information in the boundary term. Then, we propose an automated coarse-to-fine segmentation method composed mainly of two levels: coarse segmentation and fine segmentation. First, the coarse segmentation level is based on minimizing the proposed energy function. Then, the fine segmentation is done by optimizing the energy function through the standard graph-cut technique. Experiments were performed on a subset of Oxford flower database and the obtained results are compared to the reimplemented method of Nilsback et al. [1]. The evaluation shows that our method consumes less CPU time and it has a satisfactory accuracy compared with the mentioned method above [1].     

Preparation of magnetic ZSM-5/Ni/fly-ash hollow microspheres using fly-ash cenospheres as the template

Magnetic ZSM-5/Ni/fly-ash hollow microspheres are prepared by using fly-ash cenospheres as the template. The preparation procedure mainly includes two steps, i.e., preparation of magnetic nickel/fly-ash composites by electroless plating and growth of the ZSM-5 layers on the nickel/fly-ash composites by a secondary growth method. The samples are characterized by scanning electron microscope, X-ray diffraction, nitrogen adsorption and vibrating sample magnetometer. The resulting ZSM-5/Ni/fly-ash hollow microspheres show integral hollow structure and magnetic property. They are floatable on water surface when the electroless plating time is 10 min and the hydrothermal synthesis time is 12 h at 180 °C. The floatability of these hollow microspheres can further be adjusted by changing the electroless plating and hydrothermal synthesis times. Furthermore, their magnetic property can also be managed by controlling the synthesis conditions.     

计算梅花扁环压降和泛点气速的新方法

随着装置大型化和节能减排要求的不断提高,有必要对QH-2型扁环填料用于气液传质过程的设计计算方法作进一步研究,为推广应用提供更为可靠的依据。文中在Φ600mm的实验塔内用水-空气体系,在很宽的喷淋密度范围内[0—200m3/(m2·h)],系统研究了QH-2型扁环填料的流体力学性能。在大量实验数据和对多种数学模型进行比较的基础上,提出了采用改进的Billet模型计算压降和基于流动参数计算液泛气速的新方法。     

A facile method to fabricate a series of micrometer scale hollow silica spheres

Hollow silica spheres (HSS) with the controllable diameters of 1.0 to 5.0 μm were successfully synthesized by adjusting the initial doubly distilled water volume in mixed ethanol-water solvent based on a complex approach that dispersion polymerization coexisted with a sol-gel process. The size of the HSS was uniform and the surface of the shell was smooth as observed by SEM. The FT-IR spectrum indicated that the inside core was completely removed. The thermal property and the compositions of core-shell spheres were investigated by TG-DSC.     

Force model considerations for glued-sphere discrete element method simulations

Despite knowing that particle shape plays a significant role in the dynamics of powder flow, most discrete element method (DEM) simulations utilize spherical particles. The reasons for using spheres are that (a) the contact detection scheme for spherical particles is simple, and (b) the contact force models for contacting spheres are well known (e.g. a Hertzian contact).Several schemes for modeling non-spherical particles have been proposed including those that involve polyhedra, ellipsoids, sphero-cylinders, and superquadrics. Perhaps the most common approach for modeling non-spherical particles, however, is using “glued spheres,” in which irregular particle shapes are produced by rigidly connecting individual, and possibly overlapping, spheres. The advantage of the glued-spheres approach is that even for complex particle shapes the simple spherical contact detection algorithm may be retained.Recent publications have focused on how approximating a given particle shape using a glued-sphere geometry affects the rebound of colliding particles [e.g. Price, M., Murariu, V., Morrison, G., 2007. Sphere clump generation and trajectory comparison for real particles. In: Fourth International Conference on Discrete Element Methods (DEM), Brisbane, Australia; Kruggel-Emden, H., Rickelt, S., Wirtz, S., Scherer, V., 2008. A study on the validity of the multi-sphere discrete element method, Powder Technology 188 (2), 153-165]. These investigations have focused on the errors introduced by approximating the geometry of the true particle shape. What has not been investigated, however, is how the spherical particle derived force models used in glued-sphere particle geometries influence the response of particle collisions. This paper demonstrates that in instances where more than a single component sphere in a glued-sphere model is involved in a contact, a modified force model must be used to produce an accurate force-deflection response.     

苏州园林造园要素法则与版式设计形式感的融合——造园要素之花木篇

本文主要通过分析苏州园林的四大造园要素之一——花木,它在园林中的分布特点、组合方式以及作用,来和版式设计的主要构成因素作类比,可以发现它们之间有融会贯通的地方。     

Measurement of Absorption and Scattering With an Integrating Sphere Detector: Application to Microalgae

A spectrometer with an integrating sphere (IS) detector was used to measure the absorbance due to scattering and absorption. Analysis of the measurement process showed that two measurements of the absorbance, one with the cuvette placed in the normal spectrometer position, and the second with the cuvette placed next to the entrance aperture of the IS detector, provide enough information to separate the contributions from scattering and molecular absorption. Measurements were carried out with mixtures of microsphere and chromophore solutions. Two cases were examined: microspheres suspended in an aqueous fluorescein solution, and microspheres suspended in an aqueous holmium oxide solution. In both cases, the proposed measurement model gave results which were in good agreement with the expected response. Measurements on microalgae suspensions yielded a molecular absorption contribution and a scattering contribution. The scattering contribution had significant spectral structure which was inversely related to the molecular absorption contribution. The absorption and scattering contributions may provide independent information on the status of chlorophyll molecules and the structure of chloroplasts in microalgae.     

焦球在半密闭电石炉中的应用

在23 MVA半密闭电石炉上试验焦球,通过从焦球的储存环境、投料工艺、料面操作等方面进行工艺优化后,焦球得到合理利用,电石产品在电耗指标基本保持不变的情况下,质量明显上升,同比工艺优化前电石发气量提高3 L/kg,优、一级品率提高5.23%,同时也降低了成本.