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Evaluation of particle packing models by comparing with published test results

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Particuology 2014年第5期12卷 108-115页

作者： K.w.chan A.K.h.Kwan Department of Civil Engineering The University of Hong Kong

The existing particle packing density models each with two or more parameters accounting for certain particle interactions （the loosening effect parameter, wall effect parameter, wedging effect parameter, and compaction index, denoted by a, b, c, and K, respectively） may be classified into the 2-parameter model （with a and b incorporated）, the compressible model （with a, b, and 1（incorporated）, and the 3- parameter model （with a, b, and c incorporated）. This paper evaluates these models by comparing their respective packing density predictions with the test results published in the literature. It was found that their accuracy varies with both the size ratio and volumetric fractions of the binary mix. In general, when the size ratio is larger than 0.65, all the packing models are sufficiently accurate. however, when the size ratio is smaller than 0.65, some of them become inaccurate and the errors tend to be larger at around the volumetric fractions giving maximum packing density. Relatively, the 3-parameter model is the most accurate and widely applicable.

关键词： Packing density Particle packing models Particle interactions

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI h.GhANDVAR E.JUMAEV s.KhATIR T.CUONG-LE school of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and science Center for Engineering Application and Technology solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANsYs, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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Towards explicit representation of an artificial neural network model: Comparison of two artificial neural network rule extraction approaches

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Petroleum 2020年第4期6卷 329-339页

作者： Veronica K.h.chan Christine w.chan Energy Informatics Laboratory Faculty of Engineering and Applied ScienceUniversity of ReginaReginaSK S4S 0A2Canada

In the quest for interpretable models,two versions of a neural network rule extraction algorithm were proposed and *** two algorithms are called the Piece-wise Linear Artificial Neural Network(PwL-ANN)and enhanced Piece-wise Linear Artificial Neural Network(enhanced PwL-ANN)*** PwL-ANN algorithm is a decomposition artificial neural network(ANN)rule extraction algorithm,and the enhanced PwL-ANN algorithm improves upon the PwL-ANN algorithm and extracts multiple linear regression equations from a trained ANN model by approximating the hidden sigmoid activation functions using N-piece linear *** doing so,the algorithm provides interpretable models from the originally trained opaque ANN models.A detailed application case study illustrates how the generated enhanced-PwL-ANN models can provide understandable IF-ThEN rules about a problem *** of the results generated by the two versions of the PwL-ANN algorithm showed that in comparison to the PwL-ANN models,the enhanced-PwL-ANN models support improved fidelities to the originally trained ANN *** results also showed that more concise rule sets could be generated using the enhanced-PwL-ANN *** a more simplified set of rules is desired,the enhanced-PwL-ANN algorithm can be combined with the decision tree *** application of the algorithms to domains related to petroleum engineering can help enhance understanding of the problems.

关键词： Artificial neural networks Rule extraction Regression problem Algorithm design

Challenge-driven design for public housing： The case of hong Kong

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Frontiers of Architectural Research 2016年第2期5卷 213-224页

作者： Ying Deng Edwin h.w. chan s.w. Poon Department of Building and Real Estate The Hong Kong Polytechnic University Kowloon Hong KongChina

Public housing （Ph） has existed in hong Kong for six decades. Previous and current challenges that have been encountered over time function as a coffective driver for design progression. however, such challenges have remained under research to be able to draw useful lessons from them. To understand how this established motif can suit the sustainability-conscious era, this study uses hong Kong as a representative case for sub-tropical compact cities by critiquing its Ph design against multiple constraints. The objective of this study is to trace the historical relationships between challenges and design progress as well as to assess current and future implications of sustainability trends on Ph design. By synthesizing data from literature, policy documents, and empirical evidence, this research develops an evolution map for Ph design in hong Kong that is driven by seven major challenges. Based on this map, a conceptual framework for intersecting considerations that envisaaes five main future prospects toward future Ph desien is also established.

关键词： Public housing Challenge Design progress hong Kong sustainability

Bifurcations of limit cycles in a Z_6-equivariant planar vector field of degree 5

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science China Mathematics 2002年第7期45卷 817-826页

作者：李继彬 h.s.Y.chan K.w.Chung school of science Kunming University of Science and Technology Kunming China Department of Mathematics City University of Hong Kong Hong Kong China

A concrete numerical example of Z6-equivariant planar perturbed hamiltonian polynomial vector fields of degree 5 having at least 24 limit cycles and the configurations of compound eyes are given by using the bifurcation theory of planar dynamical systems and the method of detection functions. There is reason to conjecture that the hilbert number h(2k + 1) ? (2k + I)2 - 1 for the perturbed hamiltonian systems.

关键词： hilbert’s 16th problem limit cycle equivariant vector field method of detection function polynomial system

spacing optimization of high power LED arrays for solid state lighting

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Journal of semiconductors 2011年第1期32卷 45-49页

作者： Y.sing chan s.w.Ricky Lee Electronic Packaging Laboratory Center for Advanced Microsystems Packaging Hong Kong University of Science and Technology

This paper provides an analytical approach to determine the optimum pitch by utilizing a thermal resistance network, under the assumption of constant luminous efficiency. This work allows an LED array design which is mounted on a printed circuit board （PCB） attached with a heat sink subject to the natural convection cooling. Being validated by finite element （FE） models, the current approach can be shown as an effective method for the determination of optimal component spacing in an LED array assembly for ssL.

关键词： high power LED thermal resistance network finite element modeling

Pluripotent stem Cells Models for huntington's Disease:Prospects and Challenges

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Journal of Genetics and Genomics 2012年第6期39卷 253-259页

作者： Richard L. Carter Anthony w.s.chan Yerkes National Primate Research Center 954 Gatewood Rd.N.E.AtlantaGA 39329USA Genetic and Molecular Biology Program Graduate Division of Biologieal and Biomedical SciencesEmory UniversityAtlantaGA 30322USA Department of human Genetics Emory University School of Medicine615 Michael St.AtlantaGA 30322USA

Pluripotent cellular models have shown great promise in the study of a number of neurological disorders. several advantages of using a stem cell model include the potential for cells to derive disease relevant neuronal cell types, providing a system for researchers to monitor disease progression during neurogenesis, along with serving as a platform for drug discovery. A number of stem cell derived models have been employed to establish in ~,itro research models of huntington＇s disease that can be used to investigate cellular pathology and screen lk^r drug and cell-based therapies. Although some progress has been made, there are a number of challenges and limitations that must be overcome before the true potential of this research strategy is achieved. In this article we review current stem cell models that have been reported, as well as discuss the issues that impair these studies. we also highlight the prospective application of huntington＇s disease stem cell models in the development of novel therapeutic strategies and advancement of personalized medicine.

关键词： stem cell models huntington's disease Induced pluripotent stem cells Drug discovery

Vascular endothelial growth factor:a double-edged sword in the development of white matter lesions

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Neural Regeneration Research 2025年第1期20卷 191-192页

作者： Narek Manukjan Daniel Fulton Zubair Ahmed wMatthijs Blankesteijn sébastien Foulquier Department of Pharmacology and Toxicology Maastricht UniversityMaastrichtThe Netherlands CARIM-school for Cardiovascular Diseases Maastricht UniversityMaastrichtThe Netherlands Neuroscience and Ophthalmology Institute of Inflammation and AgeingUniversity of BirminghamEdgbastonBirminghamUK Centre for Trauma sciences Research University of BirminghamEdgbastonBirminghamUK MheNs-school for Mental health and Neuroscience Maastricht UniversityMaastrichtThe Netherlands Department of Neurology Maastricht University Medical CenterMaastrichtThe Netherlands

As the population ages,the burden of age-related diseases becomes ***,over 55 million people suffer from dementia worldwide,with Alzheimer’s disease being the most common ***,it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease(csVD)may be a more detrimental cause for dementia(Cuadrado-Godia et al.,2018).It is estimated that 10%-30%of the elderly population and 35%-90%of all dementia patients exhibit signs of *** term csVD refers to pathology affecting the small vessels of the brain,which can lead to lacunar cerebral infarcts,enlarged perivascular spaces,and cortical hemorrhages(Cuadrado-Godia et al.,2018).CsVD is often associated with cognitive decline,gait problems,and dementia(Cuadrado-Godia et al.,2018).

关键词： pathology becoming white

Chloroform Aided Extraction spectrophotometric Determination of Rhenium Using Thiocyanate Complexing Agent

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Journal of Materials science & Technology 2005年第2期21卷 239-242页

作者： E.Keshavarz Alamdari s.K.sadrnezhaad Z.mos-hefi shabestari Department of Mining and Metallurgical Engineering Amirkabir University of Technology Hafez Ave. TehranIranDepartment of Materials Science and EngineeringSharif University of Technology P.O.Box 11365-9466 Tehran IranDepartment of Mining and Metallurgical Engineering Amirkabir University of Technology Hafez Ave. TehranIran

A new technique is developed for quantitative determination of rhenium in aqueous media containing molybdenum, iron and copper ions. The method seems easier and more accurate than the traditional ones. It consists of the formation of rhenium thiocyanate complex, which is extracted with chloroform at the presence of hydrochloric acid. This complex is a highly visible light absorbent that can easily be detected with the aid of a spectrophotometer. The maximum absorbance (λmax) observed for this complex was in the visible range of 430-435 nm. The experimental results showed that in a concentration range from 0.5-8 mg/L, the absorbance behavior of the rhenium thiocyanate complex is followed to the Beer-Lambert law.

关键词： Rhenium solvent extraction spectrophotometry Thiocyanate Chloroform