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Journal of the Operations Research Society of China 2024年第3期12卷 757-771页

作者： Shan Jiang ka-Meng Nip School of Management Xiamen UniversityXiamen361005FujianChina School of Mathematical Sciences Xiamen UniversityXiamen361005FujianChina

In this work,we study the conic quadratic mixed-integer formulation for assortment optimization problem under the mixture of multinomial logit(MMNL)*** MMNL model generalizes the widely studied multinomial logit choice model and can approximate any random utility model with an arbitrary additive *** important operational decision problem in revenue management is assortment optimization problem,which aims to find a subset of products to make available to customers that maximizes the expected revenue of the *** is known that assortment optimization problem under the MMNL model is NP-hard and inapproximable within any constant performance *** used methods for solving such problem are heuristical approaches or customized combinatorial optimization *** the meanwhile,studies related to global optimization approaches are relatively *** propose an enhanced conic quadratic mixed-integer formulation for solving assortment optimization problem under the MMNL model with a higher computational ***,we conduct extensive numerical experiments to demonstrate that the proposed reformulation significantly outperforms the existing conic reformulations for assortment optimization under the MMNL model.

关键词： Assortment optimization MMNL model Conic reformulation Capacitated constrained

Coupled quantum molecular cavity optomechanics with surface plasmon enhancement

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Photonics Research 2017年第5期5卷 450-456页

作者： JIAN LIU ka-DI ZHU Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education) School of Physics and Astronomy Shanghai Jiao Tong University

Cavity optomechanics is applied to study the coupling behavior of interacting molecules in surface plasmon systems driven by two-color laser beams. Different from the traditional force–distance measurement, due to a resonant frequency shift or a peak splitting on the probe spectrum, we have proposed a convenient method to measure the van der Waals force strength and interaction energy via nonlinear spectroscopy. The minimum force value can reach approximately 10^(-15) N, which is 3 to 4 orders of magnitude smaller than the widely applied atomic force microscope(AFM). It is also shown that two adjacent molecules with similar chemical structures and nearly equal vibrational frequencies can be easily distinguished by the splitting of the transparency peak. Based on this coupled optomechanical system, we also conceptually design a tunable optical switch by van der Waals interaction. Our results will provide new approaches for understanding the complex and dynamic interactions inmolecule–plasmon systems.

关键词： Coupled quantum molecular cavity optomechanics with surface plasmon enhancement THz

Building an e-Portfolio with a learning plan centric approach

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第1期13卷 37-47页

作者： Lam-for KWOK ka-shing CHAN Department of Computer Science City University of Hong Kong

A portfolio records achievements in the personal growth process. A personal development e-Portfolio assists an individual in planning his/her development path and reflecting upon his/her own learning. In this article, we propose an approach to constructing a personal development portfolio. An abstract information model is presented to support such a portfolio. The information model is proposed based upon and according to IMS standards. The use of this approach is illustrated by way of a prototype e-Portfolio system. The usage scenario and limitations of such a portfolio are also discussed.

关键词： E-Portfolio Educational technology system Lifelong learning

Advantageous mechanochemical synthesis of copper(Ⅰ)selenide semiconductor,characterization,and properties

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Frontiers of Chemical Science and Engineering 2022年第3期16卷 433-442页

作者： katarína gáborová Marcela Achimovičová Michal Hegedüs Vladimír girman Mária kaňuchová Erika Dutková Institute of geotechnics Slovak Academy of SciencesKošice04001Slovakia Institute of Metallurgy Faculty of MaterialsMetallurgy and RecyclingTechnical UniversityKošice04201Slovakia Synthon s.r.o.Blansko67801Czech Republic Faculty of Science Pavol JozefŠafárik UniversityKošice04154Slovakia Institute of Earth Resources Faculty of MiningEcologyProcess Control and GeotechnologiesTechnical UniversityKošice04200Slovakia

Copper(I)selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball *** kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se *** X-ray diffraction confirmed the orthorhombic crystal structure of Cu_(2)Se with the crystallite size∼25 *** surface chemical structure was studied by X-ray photoelectron spectroscopy,whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu^(+)and Se^(2−)oxidation *** electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure,as *** optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence *** direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size *** type of Cu_(2)Se synthesis can be easily adapted to production dimensions using an industrial vibratory *** advantages of mechanochemical synthesis represent the potential for inexpensive,environmentally-friendly,and waste-free manufacturing of Cu_(2)Se.

关键词： Cu_(2)Se berzelianite nanocrystalline semiconductor mechanochemical synthesis planetary ball mill

Microstructure and Property Relationships in Resistance Spot Weld between 7114 Interstitial Free Steel and 304 Austenitic Stainless Steel

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Journal of Materials Science & Technology 2006年第3期22卷 375-381页

作者： Ahmet Hasanba■o■lu Ramazan kaar Department of Metal Education karabük Technical Education Faculty Karabük 78100 Turkey

Due to the differences in physical, chemical and mechanical properties of the base metals, the resistance spot welding of dissimilar materials is generally more challenging than that of similar materials. The influence of the primary welding parameters affecting the heat input such as peak current on the morphology, microhardness, and tensile shear load bearing capacity of dissimilar welds between 304 grades austenitic and 7114 grade interstitial free steel has been investigated in this study. The optimum welding parameters producing maximum joint strength were established at a peak current of 9 ka, where the electrode force is kept 6×10^-5 Pa and weld time is kept constant 17 cycles, respectively. The primary cause of weakening the weldment is identified as the excessive grain growing region of heat affected zone （HAZ） in case of 7114 grade interstitial free steel.

关键词： Resistance spot weld Interstitial free steel Austenitic stainless steel

Investigation of effects of Cocamide Diethanolamide chemical on physical and rheological properties of bituminous binder

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Frontiers of Structural and Civil Engineering 2022年第1期16卷 99-116页

作者： gizem kaCAROgLU Mehmet SALTAN Department of Civil Engineering Suleyman Demirel UniversityIsparta 32200Turkey

In this study,bituminous binder was modified with Cocamide Diethanolamide chemical,a non-ionic surfactant,and the physical and rheological properties of modified binders were *** addition,Cocamide Diethanolamide has been used for the first time to modify bituminous binder,and this situation makes the study *** binder was modified more than once with the chemical by changing modification parameters and using certain additive ratios(1%,3%,and 5%).The effects of different modification parameters and chemical additive on modified samples were investigated with conventional bitumen tests(softening point,penetration,ductility)and Superpave tests(rotational viscometer,rolling thin film oven test,pressure aging vessel,dynamic shear rheometer,bending beam rheometer).In addition,the structural characteristics of the reference binder and modified samples were examined by X-ray diffraction,Fourier Transform Infrared Spectroscopy,scanning electron microscopy,and energy dispersive X-ray *** examinations showed that Cocamide Diethanolamide softens bituminous binder and lowers processing *** addition,compared to reference binder,rutting resistances of modified bituminous binders decreased with the increase of additive ***,modification with Cocamide Diethanolamide increased the resistance to fatigue cracks and thermal cracks.

关键词： Cocamide Diethanolamide bitumen modification rheology Superpave tests

Economic analysis in product design——A case study of a TCM dietary supplement

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Chinese Journal of Chemical Engineering 2016年第1期24卷 202-214页

作者： Yuen Shan Cheng ka Yip Fung ka Ming Ng Christianto Wibowo Department of Chemical and Biomolecular Engineering The Hong Kong University of Science and Technology ClearWaterBay Technology Inc.

An approach for the economic analysis of chemical product design is proposed. It takes into account of customers' preference on product quality and economic considerations such as pricing, profit, market share, capital investment, and operating cost. The activities needed to support business decision making – identifying product quality, estimating product cost, calculating financial metrics, and performing make–buy analysis – are *** design of a ganoderma lucidum dietary supplement, a traditional Chinese medicinal(TCM) product, is used to illustrate all the activities in this approach.

关键词： Product design Product conceptualization TCM dietary supplement Economic analysis Make–buy analysis

Exacerbated VEgF up-regulation accompanies diabetes-aggravated hemorrhage in mice after experimental cerebral ischemia and delayed reperfusion

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Neural Regeneration Research 2022年第7期17卷 1566-1575页

作者： Angela ka Wai Lai Tsz Chung Ng Victor ka Lok Hung ka Cheung Tam Chi Wai Cheung Sookja Kim Chung Amy Cheuk Yin Lo Department of Ophthalmology Li Ka Shing Faculty of MedicineThe University of Hong KongHong Kong Special Administration RegionChina Department of Anesthesiology Laboratory and Clinical Research Institute for PainThe University of Hong KongHong Kong Special Administration RegionChina Macao University of Science and Technology TaipaMacao Special Administration RegionChinaSchool of Biomedical SciencesThe State Key Laboratory of Pharmaceutical BiotechnologyThe University of Hong KongHong Kong Special Administration RegionChina

Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated *** mechanisms underlying exacerbated hemorrhage are not fully *** study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2Akita/+mice to mimic patients with diabetes undergoing delayed mechanical *** results showed that at as early as 2 hours after reperfusion,Ins2Akita/+mice exhibited rapid development of neurological deficits,increased infarct and hemorrhagic transformation,together with exacerbated down-regulation of tight-junction protein ZO-1 and upregulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2+/+*** indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion,and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after *** observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor(VEgF)and its downstream phospho-Erk1/2 at 2 hours after reperfusion,which was suggestive of premature angiogenesis induced by early VEgF up-regulation,resulting in rapid vessel disintegration in diabetic *** reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2Akita/+mice,which suggests that the exacerbated VEgF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic *** conclusion,the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy,and diabetes-induced accelerated VEgF up-regulation is likely to underlie exacerbated hemorrhagic transformat

关键词： blood-brain barrier brain injury diabetes mellitus hemorrhagic transformation infarct ischemia/reperfusion injury middle cerebral artery occlusion mouse model stroke vascular endothelial growth factor

Semi-empirical modeling of volumetric efficiency in engines equipped with variable valve timing system

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Journal of Central South University 2016年第12期23卷 3132-3142页

作者： Mostafa ghajar Amir Hasan ka kaee Behrooz Mashadi Department of Automotive Engineering Iran university of Science and Technology

Volumetric efficiency and air charge estimation is one of the most demanding tasks in control of today's internal combustion ***,using three-way catalytic converter involves strict control of the air/fuel ratio around the stoichiometric point and hence requires an accurate model for air charge ***,high degrees of complexity and nonlinearity of the gas flow in the internal combustion engine make air charge estimation a challenging *** is more obvious in engines with variable valve timing systems in which gas flow is more complex and depends on more functional *** results in models that are either quite empirical(such as look-up tables),not having interpretability and extrapolation capability,or physically based models which are not appropriate for onboard *** these problems,a novel semi-empirical model was proposed in this work which only needed engine speed,load,and valves timings for volumetric efficiency *** accuracy and generalizability of the model is shown by its test on numerical and experimental data from three distinct *** test errors are 0.0316,0.0152 and 0.24 for the three engines,*** the performance and complexity of the model were compared with neural networks as typical black box *** the complexity of the model is less than half of the complexity of neural networks,and its computational cost is approximately 0.12 of that of neural networks and its prediction capability in the considered case studies is usually *** results show the superiority of the proposed model over conventional black box models such as neural networks in terms of accuracy,generalizability and computational cost.

关键词： engine modeling modeling and simulation spark ignition engine volumetric efficiency variable valve timing

Interface formation energy,bonding,energy band alignment in α-NaYF4 related core shell models:For future multi-layer core shell luminescence materials

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Journal of Rare Earths 2017年第4期35卷 315-334页

作者：黄勃龙董浩 Wong ka-Leung 孙聆东严纯华 Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsPKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic ChemistryCollege of Chemistry and Molecular EngineeringPeking University Department of Chemistry Hong Kong Baptist University

To break through the bottle-neck of quantum yield in upconversion （UC） core-shell system, we elucidated that the energy transfer efficiency in core-shell system had an evident contribution from the charge transfer of interface with related to two factors：（i） band offsets and （2） binding energy area density. These two variables were determined by material intrinsic properties and core-shell thickness ratio. We further unraveled the mechanism of non-radiative energy transfer by charge transfer induced dipole at the inter- face, based on a quasi-classical derivation from F6rster type resonant energy transfer （FRET） model. With stable bonding across the interface, the contributions on energy transfer in both radiative and non-radiative energy transfer should also be accounted together in Auzel＇s energy transfer （ETU） model in core-shell system. Based on the discussion about interface bonding, band offsets, and forma- tion energies, we figured out the significance of interface bonding induced gap states （IBIgS） that played a significant role for influ- encing the charge transfer and radiative type energy transfer. The interface band offsets were a key factor in dominating the non-radiative energy transfer, which was also correlated to core-shell thickness ratio. We found that the energy area density with re- lated to core/shell thickness ratio followed the trend of Boltzman sigmoidal growth function. By the physical trend, this work contrib- uted a reference how the multi-layered core-shell structure was formed starting from the very beginning within minimum size. A route was paved towards a systematic study of the interface to unveil the energy transfer mechanism in core-shell systems.

关键词： interface band-offset core-shell energy-transfer rare earths