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compressive Strength, Pore Size Distribution and chloride-ion Penetration of Recycled Aggregate concrete Incorporating class-F Fly Ash

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Journal of Wuhan University of Technology(materials Science) 2006年第4期21卷 130-136页

作者：寇世聪 c S poon Department of civil and Structural Engineering The Hong Kong Polytechnic University Hung HomKowloon Hong Kong

The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb：tures were prepared. The concrete mixtures in series I had a water-to-binder ratio and a cement content of 0.55 and 410 kg/ m^3 , respectively. The concrete rnixtures in series II had a water-to-binder ratio and a cement content of 0.45 and 400 kg/ ml respectively. Recycled aggregate was ased as 20% , 50% , and 100% replacements of natural coarse aggregate in the concrete mixtures in both series. In cutdition, fly ash was used as 0% , 25% and 35% by weight replacements of cement. The results show that the compressive strengths of the concrete decreased as the recycled aggregate and the fly ash contents increased. The total porosity and average porosity diameter of the concrete increased us the recycled aggregate content increased. Furtherrruore , an increase in the recycled aggregate content decreased the resistance to chloride ion penetration. Nevertheless, the replacement of cement by 25% fly ush improved the resistance to chloride ion penetration and pore diameters and reduced the total porosity of the recycled aggregate concrete.

关键词： durability properties recycled aggregate concrete fly ash

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非晶硅薄膜的镍诱导横向晶化工艺及其特性

Journal of Semiconductors 2001年第1期22卷 57-60页

作者：秦明 vincentm.c.poon 东南大学微电子中心南京210096 香港科技大学电子与电机工程系

报道了镍诱导非晶硅薄膜的晶化技术 ,探讨了镍诱导晶化机理 .详细调查了诱导晶化时间和温度对晶化速率的影响 ,并用 Raman、AFm和 TEm等测试了材料的特性 .实验结果发现用该方法可以获得较大晶粒的多晶 ;在晶化温度为 6 2 5℃左右时晶... 详细信息

报道了镍诱导非晶硅薄膜的晶化技术 ,探讨了镍诱导晶化机理 .详细调查了诱导晶化时间和温度对晶化速率的影响 ,并用 Raman、AFm和 TEm等测试了材料的特性 .实验结果发现用该方法可以获得较大晶粒的多晶 ;在晶化温度为 6 2 5℃左右时晶体横向晶化速率最高 .如要获得较长的晶体。

关键词：镍诱导非晶硅薄膜横向晶化工艺

Physics-based,data-driven approach for predicting natural ventilation of residential high-rise buildings

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Building Simulation 2022年第1期15卷 129-148页

作者： vincent J.L.Gan Boyu Wang c.m.chan A.U.Weerasuriya Jack c.P.cheng Department of Building School of Design and EnvironmentNational University of SingaporeSingapore117566 Department of civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong999077China

Natural ventilation is particularly important for residential high-rise buildings as it maintains indoor human comfort without incurring the energy demands that air-conditioning *** improve a building’s natural ventilation,it is essential to develop models to understand the relationship between wind flow characteristics and the building's *** more effort is still needed for developing such reliable,accurate,and computationally economical models instead of currently the most popular physics-based models such as computational fluid dynamics(cFD)*** paper,therefore,presents a novel model developed based on physics-based modelling and a data-driven approach to evaluate natural ventilation in residential high-rise *** model first uses cFD to simulate wind pressures on the exterior surfaces of a high-rise *** the surface pressures have been obtained,multizone modelling is used to predict the air change per hour(AcH)for different flats in various ***-driven prediction models are then developed using data from the simulation and deep neural networks that are based on mean absolute error,mean absolute percentage error,and a fusion algorithm *** data-driven models are used to predict the AcH of 25 *** results from multizone modelling and data-driven modelling are *** results imply a high accuracy of the data-driven prediction in comparison with physics-based *** fusion algorithm-based neural network performs best,achieving 96%accuracy,which is the highest of all models *** study contributes a more efficient and robust method for predicting wind-induced natural *** findings describe the relationship between building design(e.g.,plan layout),distribution of surface pressure,and the resulting AcH,which serve to improve the practical design of sustainable buildings.

关键词： computational fluid dynamics data-driven prediction machine learning multizone model natural ventilation residential building

Generation and optical display of a binary-sampled phase-only hologram

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chinese Optics Letters 2016年第1期14卷 12-15页

作者： P. W. m. Tsang Y.-T. chow T.-c. poon J.-P. Liu Department of Electronic Engineering City University of Hong Kong Hong Kong SAR China Bradley Department of Electrical and computer Engineering Virginia Tech Blacksburg VA 24061 USA Department of Photonics Feng Chia University No. 100 Wenhwa Rd. Taichung 407 China

Past research has demonstrated that a phase-only hologram can be obtained by down-sampling the intensity image of the object scene prior to the generation of the hologram. In this Letter, we extend the method to the generation of binary phase-only holograms. A hologram derived with our proposed method is referred to as a binary-sampled phase-only hologram （BSPOH）. Being different from the parent scheme, we have adopted an off- axis configuration in the generation of the BSPOH to avoid the quantization noise, the zeroth-order light, and the conjugate lights. An experimental evaluation reveals that the reconstructed image of the BSPOH is of good quality, and only contains slight amount of noise.

关键词： Bins Holographic displays Lithography

An enhanced method for fast generation of hologram sub-lines

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chinese Optics Letters 2009年第12期7卷 1092-1096页

作者： P. W. m. Tsang J. P. Liu K. W. K. cheung T.-c. poon Department of Electronic Engineering City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR China Department of Photonics Feng Chia University No. 100 Wenhwa Rd. Seatwen Taichung 40724 China Bradley Department of Electrical and computer Engineering Virginia Tech Blacksburg Virginia 24061 USA

Sub-lines are one-dimensional diffraction patterns representing the light beams emerging from horizontal planes of an object image. Past research has demonstrated that the sub-lines can be encapsulated as a multi-bank filtering process, and implemented with a field programmable gate array （FPGA） device. As the complexity of the filters is high, their length and the number of input pins have to be reduced substantially, hence leading to degradation on the reconstructed images. We propose an enhanced method to overcome the problem by binarizing the filters＇ coefficients, and half-toning the pixel intensities of the object image. Experimental evaluation reveals that our method results in reconstructed images are superior to that obtained with the parent method.

关键词： Diffraction Field programmable gate arrays (FPGA) Holographic interferometry

Peroxyacetyl nitrate measurements by thermal dissociation-chemical ionization mass spectrometry in an urban environment： performance and characterizations

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Frontiers of Environmental Science & Engineering 2017年第4期11卷 145-152页

作者： Xinfeng Wang Tao Wang Likun Xue Wei Nie Zheng Xu Steven c. N. poon Wenxing Wang Environment Research Institute Shandong University Jinan 250100 China Department of civil and Environmental Engineering Hong Kong Polytechnic University Hong Kong 999077 China Institute for climate and Global change Research & School of Atmospheric Sciences Nanjing University Nanjing 210023 China

Peroxyacetyl nitrate （PAN） is an important indicator of photochemical smog and has adverse effects on human health and vegetation growth. A rapid and h!ghly selective technique of thermal dissociation chemical ionization mass spectrometry （TD-cImS） was recently developed to measure the abundance of PAN in real time; however, it may be subject to artifact in the presence of nitric oxide （NO）. In this study, we tested the interference of the PAN signal induced by NO, evaluated the performance of TD- cImS in an urban environment, and investigated the concentration and formation of PAN in urban Hong Kong. NO caused a significant underestimation of the PAN signal in TD-cImS, with the underestimation increasing sharply with NO concentration and decreasing slightly with PAN abundance. A formula was derived to link the loss of PAN signal with the concentrations of NO and PAN, which can be used for data correction in PAN measurements. The corrected PAN data from TD- cImS were consistent with those from the commonly used gas chromatography with electron capture detection, which confirms the utility of TD-cImS in an urban environment in which NO is abundant. In autumn of 2010, the hourly average PAN mixing ratio varied from 0.06 ppbv to 5.17 ppbv, indicating the occurrence of photochemical pollution in urban Hong Kong. The tbrmation efficiency of PAN during pollution episodes was as high as 3.9 to 5.9 ppbv per 100 ppbv ozone. The efficiency showed a near-linear increase with NO, concentration, suggesting a control policy of NO,. reduction for PAN pollution.

关键词： TD-cImS Peroxyacetyl nitrate Interference Photochemical pollution Formation efficiency

Biosynthesis of callose and cellulose by Detergent Extracts of Tobacco cell membranes and Quantification of the Polymers Synthesized in vitro

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Journal of Integrative Plant Biology 2010年第2期52卷 221-233页

作者： carolina cifuentes vincent Bulone Anne mie c.Emons Laboratory of Plant cell Biology Wageningen University Division of Glycoscience School of BiotechnologyRoyal Institute of TechnologyAlbaNova University Center Department of Biomolecular Systems FOM Institute for Atomic and Molecular Physics

The conditions that favor the in vitro synthesis of cellulose from tobacco BY-2 cell extracts were determined. The procedure leading to the highest yield of cellulose consisted of incubating digitonin extracts of membranes from 11-day-old tobacco BY-2 cells in the presence of 1 mm UDP-glucose, 8 mm ca^2＋ and 8 mm mg^2＋. Under these conditions, up to nearly 40% of the polysaccharides synthesized in vitro corresponded to cellulose, the other polymer synthesized being callose. Transmission electron microscopy analysis revealed the occurrence of two types of structures in the synthetic reactions. The first type consisted of small aggregates with a diameter between 3 and 5 nm that associated to form fibrillar strings of a maximum length of 400 nm. These structures were sensitive to the acetic/nitric acid treatment of Updegraff and corresponded to callose. The second type of structures was resistant to the Updegraff reagent and corresponded to straight cellulose microfibrils of 2-3 nm in diameter and 200 nm to up to 5 μm in length. In vitro reactions performed on electron microscopy grids indicated that the minimal rate of microfibril elongation in vitro is 120 nm/min. measurements of retardance by liquid crystal polarization microscopy as a function of time showed that small groups of microfibrils increased in retardance by up to 0.047 nm/min per pixel, confirming the formation of organized structures.

关键词： Biosynthesis of callose and cellulose by Detergent Extracts of Tobacco cell membranes and Quantification of the Polymers Synthesized in vitro

Review on theory and applications of wavefront recording plane framework in generation and processing of digital holograms

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chinese Optics Letters 2013年第1期11卷 18-24页

作者： P. W. m. Tsang T.-c. poon Department of Electronic Engineering City University of Hong Kong Bradley Department of Electrical and computer Engineering

The wavefront recording plane （WRP）, subsequently generalized to be known as the virtual diffraction plane （VDP）, is a recent concept that has been successfully deployed in fast generation and processing of digital holograms. In brief, the WRP and its extension, the VDP, is a hypothetical plane that is located between the hologram and the object scene, and which is at close proximity to the latter. As such, the fringe patterns on the hypothetical plane are carrying the holistic information of the hologram, as well as the local optical properties of the object scene. This important property enables a hologram to be processed with classical image processing techniques that are normally unsuitable for handling holographic information. In this paper we shall review a number of works, that have been developed based on the framework of the WRP and the VDP.

关键词： Review on theory and applications of wavefront recording plane framework in generation and processing of digital holograms

Data-embedded-error-diffusion hologram(Invited Paper)

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chinese Optics Letters 2014年第6期12卷 76-79页

作者： P. W. m. Tsang T.-c. poon Department of Electronic Engineering City University of Hong KongHong Kong SAR China Bradley Department of Electrical and computer Engineering Virginia TechBlacksburg VA 24061 USA Shanghai Institute of Optics and Fine mechanics Chinese Academy of SciencesShanghai 201800 China

This paper describes a method for converting a complex Fresnel hologram into a phase-only hologram that can be embedded with large amount of data. Briefly, each row of pixels in the hologram is scanned sequentially in a left-to-right direction. The magnitude of each visited pixel is set to a constant, and its phase is embedded with the data. Subsequently, the error is diffused to the neighborhood pixels. The phase hologram realized with such means, which is referred to as the data-embedded-error-diffusion （DEED） hologram, is capable of preserving high fidelity on the content of the hologram and the embedded data.

关键词： Data-embedded-error-diffusion hologram