Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable device...Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable devices and building-integrated applications.However,the efficient harvesting of photons is the core hindrance towards efficient,flexible PV.Light management by nanostructures and nanomaterials has opened new pathways for sufficient solar energy harvesting.Nanostructures on top surfaces provide an efficient pathway for the propagation of light.Aside from suppressing incident light reflection,micro-structured back-reflectors reduce transmission via multiple reflections.Nanostructures themselves can be the absorber layer.Photovoltaics based on high-crystallinity nanostructured light absorbers demonstrate enhanced power conversion efficiency(PCE)and excellent mechanical flexibility.To acquire a deep understanding of the impacts of nanostructures,herein,a concise overview of the recent development in the design and application of nanostructures and nanomaterials for photovoltaics is summarized.展开更多
The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence nanocrystals.Using photo-induced alignment technique,the QRs can be oriented in...The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence nanocrystals.Using photo-induced alignment technique,the QRs can be oriented in liquid crystal polymer matrix at a large scale.In this article,a 2D Dammann grating pattern,within“SKL”characters domains aligned QRs in composite film,was fabricated by multi-step photo exposure using several photo masks,and a continuous geometric lens profile pattern aligned QRs was realized by the single step polarization converting holographic irradiation method.Both polarized optical microscope and fluorescence microscope are employed to determine the liquid crystal director profiles and QRs anisotropic excitation properties.We have been able to orient the QRs in fine binary and continuous patterns that confirms the strong quantum rod aligning ability of the proposed method.Thus,the proposed approach paves a way for photoinduced flexible QRs alignments to provide a highly specific and difficult-to-replicate security application at a large scale.展开更多
Flexible energy devices are the building blocks for next-generation wearable electronics.Flexible energy devices are expected to have multiple functions,such as energy conversion from light to electricity and vice ver...Flexible energy devices are the building blocks for next-generation wearable electronics.Flexible energy devices are expected to have multiple functions,such as energy conversion from light to electricity and vice versa,energy generation from triboelectric,energy storage and so on.These functions can be efficiently realized by solar cells,light-emitting diodes(LEDs),triboelectric nanogenerators(TENG),batteries and supercapacitors,etc.The flexible energy devices can be integrated into flexible,wearable,and/or portable platforms to enable wide application prospects in the fields of information,energy,medical care,national defense,etc.However,flexible energy devices face more challenges when compared to their rigid counterparts,which requires more breakthroughs and research efforts on fabrication techniques,materials innovation,novel structure designs,and deep physical understandings.展开更多
Information and communication technologies are spreading rapidly due to their fast proliferation in many fields.The number of Internet users has led to a spike in cyber-attack incidents.E-commerce applications,such as...Information and communication technologies are spreading rapidly due to their fast proliferation in many fields.The number of Internet users has led to a spike in cyber-attack incidents.E-commerce applications,such as online banking,marketing,trading,and other online businesses,play an integral role in our lives.Network Intrusion Detection System(NIDS)is essential to protect the network from unauthorized access and against other cyber-attacks.The existing NIDS systems are based on the Backward Oracle Matching(BOM)algorithm,which minimizes the false alarm rate and causes of high packet drop ratio.This paper discussed the existing NIDS systems and different used pattern-matching techniques regarding their weaknesses and limitations.To address the existing system issues,this paper proposes an enhanced version of the BOM algorithm by using multiple pattern-matching methods for the NIDS system to improve the network performance.The proposed solution is tested in simulation with existing solutions using the Snort and NSL-KDD datasets.The experimental results indicated that the proposed solution performed better than the existing solutions and achieved a 5.17%detection rate and a 0.22%lower false alarm rate than the existing solution.展开更多
The energy internet has emerged as a promising area of research in power systems with distributed generation.Similar to an internet router to connect and switch networks,the energy router within the energy internet pl...The energy internet has emerged as a promising area of research in power systems with distributed generation.Similar to an internet router to connect and switch networks,the energy router within the energy internet plays a crucial role to integrate and distribute the energy flow.This paper provides an overview of the application and challenges associated with energy routers in the energy internet.Firstly,the ability of energy routers to bring together multiple energy sources and information is highlighted.Secondly,the discrep-ancies in power structure when energy routers are utilised in different voltage‐level power grids are discussed.Besides,the roles,structures,and design requirements of energy routers and how they interconnect with the power system,as well as some practical examples of energy router are delved.Finally,the main challenges faced by energy routers are summarised.展开更多
The authors propose a distributed field mapping algorithm that drives a team of robots to explore and learn an unknown scalar field using a Gaussian Process(GP).The authors’strategy arises by balancing exploration ob...The authors propose a distributed field mapping algorithm that drives a team of robots to explore and learn an unknown scalar field using a Gaussian Process(GP).The authors’strategy arises by balancing exploration objectives between areas of high error and high variance.As computing high error regions is impossible since the scalar field is unknown,a bio-inspired approach known as Speeding-Up and Slowing-Down is leveraged to track the gradient of the GP error.This approach achieves global field-learning convergence and is shown to be resistant to poor hyperparameter tuning of the GP.This approach is validated in simulations and experiments using 2D wheeled robots and 2D flying mini-ature autonomous blimps.展开更多
Broadband photodetectors with unprecedented responsivity were reported.It widens the application of organometal halide perovskites in highly sensitive,low-cost and flexible photodetectors.The fundamental device physic...Broadband photodetectors with unprecedented responsivity were reported.It widens the application of organometal halide perovskites in highly sensitive,low-cost and flexible photodetectors.The fundamental device physics revealed will have significant impact on the design of future ultrasensitive photodetectors and other optoelectronic devices.展开更多
基金the National Natural Science Foundation of China(Project No.51672231)the Science and Technology Plan of Shenzhen(Project Nos.JCYJ20170818114107730,JCYJ20180306174923335)+2 种基金the General Research Fund(Project Nos.16309018,16214619)from the Hong Kong Research Grant Council.Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory(Project No.2020B1212030010)HKUST Fund of Nanhai(Grant No.FSNH-18FYTRI01)the Center for 1D/2D Quantum Materials and the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST and Foshan Innovative and Entrepreneurial Research Team Program(2018IT100031).
文摘Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable devices and building-integrated applications.However,the efficient harvesting of photons is the core hindrance towards efficient,flexible PV.Light management by nanostructures and nanomaterials has opened new pathways for sufficient solar energy harvesting.Nanostructures on top surfaces provide an efficient pathway for the propagation of light.Aside from suppressing incident light reflection,micro-structured back-reflectors reduce transmission via multiple reflections.Nanostructures themselves can be the absorber layer.Photovoltaics based on high-crystallinity nanostructured light absorbers demonstrate enhanced power conversion efficiency(PCE)and excellent mechanical flexibility.To acquire a deep understanding of the impacts of nanostructures,herein,a concise overview of the recent development in the design and application of nanostructures and nanomaterials for photovoltaics is summarized.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)the National Natural Science Foundation of China(Nos.62005180,61935013)+2 种基金the Zhejiang Lab Open Research Project(No.K2022MG0AB01)RGC of Hong Kong S.A.R.(No.26202019)the State Key Laboratory of Advanced Displays and Optoelectronics Technologies(HKUST)(No.ITC-PSKL12EG02)。
文摘The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence nanocrystals.Using photo-induced alignment technique,the QRs can be oriented in liquid crystal polymer matrix at a large scale.In this article,a 2D Dammann grating pattern,within“SKL”characters domains aligned QRs in composite film,was fabricated by multi-step photo exposure using several photo masks,and a continuous geometric lens profile pattern aligned QRs was realized by the single step polarization converting holographic irradiation method.Both polarized optical microscope and fluorescence microscope are employed to determine the liquid crystal director profiles and QRs anisotropic excitation properties.We have been able to orient the QRs in fine binary and continuous patterns that confirms the strong quantum rod aligning ability of the proposed method.Thus,the proposed approach paves a way for photoinduced flexible QRs alignments to provide a highly specific and difficult-to-replicate security application at a large scale.
文摘Flexible energy devices are the building blocks for next-generation wearable electronics.Flexible energy devices are expected to have multiple functions,such as energy conversion from light to electricity and vice versa,energy generation from triboelectric,energy storage and so on.These functions can be efficiently realized by solar cells,light-emitting diodes(LEDs),triboelectric nanogenerators(TENG),batteries and supercapacitors,etc.The flexible energy devices can be integrated into flexible,wearable,and/or portable platforms to enable wide application prospects in the fields of information,energy,medical care,national defense,etc.However,flexible energy devices face more challenges when compared to their rigid counterparts,which requires more breakthroughs and research efforts on fabrication techniques,materials innovation,novel structure designs,and deep physical understandings.
文摘Information and communication technologies are spreading rapidly due to their fast proliferation in many fields.The number of Internet users has led to a spike in cyber-attack incidents.E-commerce applications,such as online banking,marketing,trading,and other online businesses,play an integral role in our lives.Network Intrusion Detection System(NIDS)is essential to protect the network from unauthorized access and against other cyber-attacks.The existing NIDS systems are based on the Backward Oracle Matching(BOM)algorithm,which minimizes the false alarm rate and causes of high packet drop ratio.This paper discussed the existing NIDS systems and different used pattern-matching techniques regarding their weaknesses and limitations.To address the existing system issues,this paper proposes an enhanced version of the BOM algorithm by using multiple pattern-matching methods for the NIDS system to improve the network performance.The proposed solution is tested in simulation with existing solutions using the Snort and NSL-KDD datasets.The experimental results indicated that the proposed solution performed better than the existing solutions and achieved a 5.17%detection rate and a 0.22%lower false alarm rate than the existing solution.
基金Guangzhou Municipal Science and Technology Project,Grant/Award Number:2023A03J0655。
文摘The energy internet has emerged as a promising area of research in power systems with distributed generation.Similar to an internet router to connect and switch networks,the energy router within the energy internet plays a crucial role to integrate and distribute the energy flow.This paper provides an overview of the application and challenges associated with energy routers in the energy internet.Firstly,the ability of energy routers to bring together multiple energy sources and information is highlighted.Secondly,the discrep-ancies in power structure when energy routers are utilised in different voltage‐level power grids are discussed.Besides,the roles,structures,and design requirements of energy routers and how they interconnect with the power system,as well as some practical examples of energy router are delved.Finally,the main challenges faced by energy routers are summarised.
文摘The authors propose a distributed field mapping algorithm that drives a team of robots to explore and learn an unknown scalar field using a Gaussian Process(GP).The authors’strategy arises by balancing exploration objectives between areas of high error and high variance.As computing high error regions is impossible since the scalar field is unknown,a bio-inspired approach known as Speeding-Up and Slowing-Down is leveraged to track the gradient of the GP error.This approach achieves global field-learning convergence and is shown to be resistant to poor hyperparameter tuning of the GP.This approach is validated in simulations and experiments using 2D wheeled robots and 2D flying mini-ature autonomous blimps.
文摘Broadband photodetectors with unprecedented responsivity were reported.It widens the application of organometal halide perovskites in highly sensitive,low-cost and flexible photodetectors.The fundamental device physics revealed will have significant impact on the design of future ultrasensitive photodetectors and other optoelectronic devices.
