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Optical fibre based artificial compound eyes for direct static imaging and ultrafast motion detection

Light(Science & Applications) 2024年第11期13卷 2649-2667页

作者： Heng Jiang chi chung tsoi Weixing Yu Mengchao Ma Mingjie Li Zuankai Wang Xuming Zhang Department of Applied Physics The Hong Kong Polytechnic University999077 Hong KongChina Photonics Research Institute(PRI) The Hong Kong Polytechnic University999077 Hong KongChina Key Laboratory of Spectral Imaging Technology Xi’an Institute of Optics and Precision MechanicsChinese Academy of Sciences710119 Xi’anChina Anhui Province Key Laboratory of Measuring Theory and Precision Instrument School of Instrument Science and Opto-Electronics EngineeringHefei University of Technology230009 HefeiChina Department of Mechanical Engineering The Hong Kong Polytechnic University999077 Hong KongChina Research Institute for Advanced Manufacturing(RIAM) The Hong Kong Polytechnic University999077 Hong KongChina

Natural selection has driven arthropods to evolve fantastic natural compound eyes(NCEs)with a unique anatomical structure,providing a promising blueprint for artificial compound eyes(ACEs)to achieve static and dynamic perceptions in complex ***,each NCE utilises an array of ommatidia,the imaging units,distributed on a curved surface to enable abundant *** has inspired the development of many ACEs using various microlens arrays,but the reported ACEs have limited performances in static imaging and motion ***,it is challenging to mimic the apposition modality to effectively transmit light rays collected by many microlenses on a curved surface to a flat imaging sensor chip while preserving their spatial relationships without *** this study,we integrate 271 lensed polymer optical fibres into a dome-like structure to faithfully mimic the structure of *** ACE has several parameters comparable to the NCEs:271 ommatidia versus 272 for bark beetles,and 180° field of view(FOV)versus 150–180° FOV for most *** addition,our ACE outperforms the typical NCEs by~100 times in dynamic response:31.3 kHz versus 205 Hz for Glossina *** with other reported ACEs,our ACE enables real-time,180° panoramic direct imaging and depth estimation within its nearly infinite depth of ***,our ACE can respond to an angular motion up to 5.6×10^(6)deg/s with the ability to identify translation and rotation,making it suitable for applications to capture high-speed objects,such as surveillance,unmanned aerial/ground vehicles,and virtual reality.

关键词： field. compound enable

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A study of influence of gravity on bulk behaviour of particulate solid

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Particuology 2008年第6期6卷 467-474页

作者： Yun-chi chung Jin Yeam Ooi Department of Civil and Environmental Engineering Nanya Institute of Technology Institute for Infrastructure & Environment School of Engineering & Electronics University of Edinburgh

This paper examines the influence of gravity on the bulk responses of a granular solid. The loading scenarios in this study include confined compression, rod penetration into a granular medium and discharging through an orifice. Similar loading and flow conditions are likely to be encountered in the stress and deformation regimes that regoliths are subjected to in extraterrestrial exploration activities including in situ resource utilisation processes. Both spherical and non-spherical particles were studied using the discrete element method （DEM）. Whilst DEM is increasingly used to model granular solids, careful validations of the simulation outcomes are rather rare. Thus in addition to exploring the effect of gravity, this paper also compares DEM simulations with experiments under terrestrial condition to verify whether DEM can produce satisfactory predictions. The terrestrial experiments were conducted with great care and simulated closely using DEM. The key mechanical and geometrical properties for the particles were measured in laboratory tests for use in the DEM simulations. A series of DEM computations were then performed under reduced gravity to simulate these experiments under extraterrestrial environment. It was found that gravity has no noticeable effect on the force transmission in the confined compression case; the loading gradient in the rod penetration is linearly proportional to the gravity; the mass flow rate in silo discharge is proportional to square root of the gravity and the angle of repose increases with reducing gravity. These findings are in agreement with expectation and existing scientific evidence.

关键词： Extraterrestrial Particulate assembly Confined compression Rod penetration Silo discharge Discrete element method Gravity effect

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Small-signal Stability Criteria in Power Electronics-dominated Power Systems:A Comparative Review

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1003-1018页

作者： Qifan Chen Siqi Bu chi Yung chung Department of Electrical and Electronic Engineer The Hong Kong Polytechnic UniversityHong KongChina Department of Electrical and Electronic Engineering Shenzhen Research InstituteCentre for Grid ModernisationInternational Centre of Urban Energy NexusCentre for Advances in Reliability and SafetyResearch Institute for Smart Energyand Policy Research Centre for Innovation and TechnologyThe Hong Kong Polytechnic UniversityHong KongChina

To tackle emerging power system small-signal stability problems such as wideband oscillations induced by the large-scale integration of renewable energy and power electronics,it is crucial to review and compare existing small-signal stability analysis *** this basis,guidance can be provided on determining suitable analysis methods to solve relevant small-signal stability problems in power electronics-dominated power systems(PEDPSs).Various mature methods have been developed to analyze the small-signal stability of PEDPSs,including eigenvalue-based methods,Routh stability criterion,Nyquist/Bode plot based methods,passivity-based methods,positive-net-damping method,lumped impedance-based methods,bifurcation-based methods,*** this paper,the application conditions,advantages,and limitations of these criteria in identifying oscillation frequencies and stability margins are reviewed and compared to reveal and explain connections and discrepancies among ***,efforts are devoted to mathematically proving the equivalence between these small-signal stability ***,the performance of these criteria is demonstrated and compared in a 4-machine 2-area power system with a wind farm and an IEEE 39-bus power system with 3 wind farms.

关键词： Impedance-based method oscillation analysis power electronic converter power electronics-dominated power system renewable power generation small-signal stability

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Organic Solar Cells at Stratospheric Condition for High Altitude Platform Station Application

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chinese Journal of Chemistry 2022年第24期40卷 2927-2932页

作者： Ram Datt Harrison Ka Hin Lee Guichuan Zhang Hin-Lap Yip Wing chung tsoi SPECIFIC Faculty of Science and EngineeringSwansea UniversityBay CampusFabian WaySwanseaSA18EN United Kingdom Department of Physics City University of Hong KongKowloonHong KongSARChina School of Semiconductor Science and Technology South China Normal UniversityFoshanGuangdong528225 China State Key Laboratory of Luminescent Materials and Devices South China University of Technology381 Wushan RoadGuangzhouGuangdong510640 China Department of Materials Science and Engineering City University of Hong KongKowloonHong KongChina School of Energy and Environment City University of Hong KongKowloonHong KongChina Hong Kong Institute for Clean Energy City University of Hong KongKowloonHong KongChina

High specific power or power to mass ratio is a critical concern of photovoltaic(PV)for aerospace *** solar cells(OSCs)have advantages such as high absorption coefficient,compatibility with flexible substrate,light-weight,***,recently OSCs achieved power conversion efficiency(PCE)over 20%with the incorporation of the non-fullerene based small molecule acceptor and high specific power is believed to be *** enter the market,high-altitude platform station(HAPS)is perhaps the first place to start *** this work,we explore and compare the in-situ performance of two high performing OSCs,using the same donor but different acceptors,in mimic HAPS environment where the pressure,temperature and the illumination conditions are *** found that the use of acceptor can result in substantial difference in the performance at low temperatures.

关键词： Organic solar cells Stratosphere High-altitude platform station Low-temperature physics Donor-acceptor systems

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Handheld 3D Scanner for Small Objects Using Kinect

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Journal of Electronic Science and Technology 2016年第4期14卷 377-383页

作者： chia-chi Hsu chung-Lin Huang Taiwan Residents Army Department of M-Commerce and Multimedia Applications Asia UniversityTaichung 41354

This paper presents a handheld 3D vision-based scanner for small objects by using Kinect. It is different from the previous color-glove-based approaches which require segmenting the target object. First, we eliminate the noises and the outliers caused by holding hands. Second, we apply Kinect-fusion algorithm and truncated signed distance function （TSDF） to represent 3D surfaces. Third, we propose a modified integration strategy to eliminate the hand effect. Fourth, we take advantage of the parallel computation of GPUs for real-time operation. The major contributions of this paper are （1） the registration precision is improved, （2） the oflline amendment and loop closure operation are not required, and （3） concave 3D object reconstruction is feasible.

关键词： Handheld 3D scanning Kinect-fusion,Truncated signed distance function (TSDF).

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Review of current progress in hole-transporting materials for perovskite solar cells

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Journal of Energy Chemistry 2022年第5期31卷 330-386页

作者： Prerna Mahajan Bhavya Padha Sonali Verma Vinay Gupta Ram Datt Wing chung tsoi Soumitra Satapathi Sandeep Arya Department of Physics University of JammuJammuJammu and Kashmir 180006India Department of Physics Khalifa University of Science and TechnologyAbu Dhabi 127788United Arab Emirates SPECIFIC College of EngineeringSwansea University Bay CampusFabian WaySA18ENSwanseaUnited Kingdom Department of Physics Indian Institute of Technology RoorkeeUttarakhand 247667India

Recent advancements in perovskites’ application as a solar energy harvester have been astonishing. The power conversion efficiency(PCE) of perovskite solar cells(PSCs) is currently reaching parity(>25 percent), an accomplishment attained over past decades. PSCs are seen as perovskites sandwiched between an electron transporting material(ETM) and a hole transporting material(HTM). As a primary component of PSCs, HTM has been shown to have a considerable effect on solar energy harvesting, carrier extraction and transport, crystallization of perovskite, stability, and price. In PSCs, it is still necessary to use a *** perovskites are capable of conducting holes, they are present in trace amounts, necessitating the use of an HTM layer for efficient charge extraction. In this review, we provide an understanding of the significant forms of HTM accessible(inorganic, polymeric and small molecule-based HTMs), to motivate further research and development of such materials. The identification of additional criteria suggests a significant challenge to high stability and affordability in PSC.

关键词： Hole transporting material Perovskite solar cells Power conversion efficiency Stability

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Interplay of laser power and pore characteristics in selective laser melting of ZK60 magnesium alloys:A study based on in-situ monitoring and image analysis

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Journal of Magnesium and Alloys 2024年第4期12卷 1346-1366页

作者： Weijie Xie Hau-chung Man chi-Wai Chan Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Mechanical and Aerospace Engineering Queen’s UniversityBelfast BT95AHUK Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHong KongChina

This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)***-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 *** morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore *** laser power led to increased pore coverage,whereas a denser structure was observed at higher laser *** laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the *** increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore *** laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher *** interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.

关键词： Selective laser melting(SLM) Magnesium(Mg)alloys Biodegradable implants Porosity In-situ monitoring

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Husserl's Intercultural Implication of Ethical Renewal and Theoretical Rationality:A Reappraisal from an East Asian Perspective

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Frontiers of Philosophy in china 2020年第3期15卷 509-531页

作者： YU chung-chi Department of Philosophy Sun Yat-sen UniversityKaohsiung City 80424China

In the Kaizo articles,written between 1922 and 1924,Husserl touched on the intercultural relationship between"the European"and"the non-European."Husserl addressed Japan as he dealt with ethical and cultural renewal in his Kaizo *** wished to spread the European spiritual gestalt,which he comprehended as a universal theoretical rationality to remote *** that time,Husserl imagined china as unfamiliar and *** even used china as a typical example of alienworld when he dealt with the problem of cultural *** paper reappraises Husserl's thesis by exploring Eurocentrism as a factor that might impede the willingness for non-Western or non-European cultures to accept the idea of European spiritual *** paper suggests that the non-Western or non-European cultures should take delight in learning from Europe and carry out what Husserl had in mind about the meaning of"renewal."

关键词： Husserl renewal theoretical attitude interculturality the idea of Europe

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Optimization of rice wine fermentation process based on the simultaneous saccharification and fermentation kinetic model

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chinese Journal of Chemical Engineering 2016年第10期24卷 1406-1412页

作者： Dengfeng Liu Hongtao Zhang chi-chung Lin Baoguo Xu Key Laboratory of Industrial Advanced Process Control for Light Industry of Ministry ofEducation Jiangnan UniversityWuxi 214122China School of Internet of Things Engineering Jiangnan University Wuxi 214122China Key Laboratory of Industrial Biotechnology of Ministry of Education Jiongnan UniversityWuxi 214122China

chinese rice wine making is a typical simultaneous saccharification and fermentation （SSF） process. During the fermentation process, temperature is one of the key parameters which decide the quality of chinese rice wine. To optimize the SSF process for chinese rice wine brewing, the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatures were determined in batch cultures using a mathematical model. The kinetic parameters as a function of temperature were evaluated using the software Origin8.0. Combing these functions with the mathematical model, an appropriate form of the model equations for the SSF considering the effects of temperature were developed. The kinetic parameters were found to fit the experimental data satisfactorily with the developed temperature-dependent model. The temperature profile for maximizing the ethanol production for rice wine fermentation was determined by genetic algorithm. The optimum temperature profile began at a low temperature of 26℃ up to 30 h. The operating temperature increased rapidly to 31.9 ℃, and then decreased slowly to 18℃ at 65 h. Thereafter, the temperature was maintained at 18 ℃ until the end of fermentation. A maximum ethanol production of 89.3 g.L 1 was attained. Conceivably, our model would facilitate the improvement of chinese rice wine production at the industrial scale.

关键词： chinese rice wine Temperature controlling Simultaneous saccharification and fermentation Optimal temperature profile

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Data-driven Operation Risk Assessment of Wind-integrated Power Systems via Mixture Models and Importance Sampling

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Journal of Modern Power Systems and Clean Energy 2020年第3期8卷 437-445页

作者： Osama Aslam Ansari Yuzhong Gong Weijia Liu chi Yung chung Department of Electrical and Computer Engineering University of SaskatchewanSaskatoonCanada

The increasing penetration of highly intermittent wind generation could seriously jeopardize the operation reliability of power systems and increase the risk of electricity outages. To this end, this paper proposes a novel data-driven method for operation risk assessment of wind-integrated power systems. Firstly, a new approach is presented to model the uncertainty of wind power in lead time. The proposed approach employs k-means clustering and mixture models(MMs) to construct time-dependent probability distributions of wind *** proposed approach can also capture the complicated statistical features of wind power such as multimodality. Then, a nonsequential Monte Carlo simulation(NSMCS) technique is adopted to evaluate the operation risk indices. To improve the computation performance of NSMCS, a cross-entropy based importance sampling(CE-IS) technique is applied. The CE-IS technique is modified to include the proposed model of wind *** method is validated on a modified IEEE 24-bus reliability test system(RTS) and a modified IEEE 3-area RTS while employing the historical data of wind generation. The simulation results verify the importance of accurate modeling of shortterm uncertainty of wind power for operation risk *** case studies have been performed to analyze the impact of transmission systems on operation risk indices. The computational performance of the framework is also examined.

关键词： Cross entropy mixture model Monte Carlo simulation operation risk power system reliability

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