Few-mode and multi-core fibers are proposed and demonstrated for contactless vital signs monitoring in this paper.In-line optical fiber interferometers using few-mode and multi-core fibers are designed and offset spli...Few-mode and multi-core fibers are proposed and demonstrated for contactless vital signs monitoring in this paper.In-line optical fiber interferometers using few-mode and multi-core fibers are designed and offset splicing is utilized for mode excitation.Extinction ratio and insertion loss are analyzed experimentally under different offset distances.The fabricated in-line interferometers are packaged under the mattress to realize contactless vital signs signals collection.By using filtering techniques,both respiration and heartbeat signals can be recovered successfully,and respiration as well as heartbeat ratio are obtained.Mode excitation and interference are theoretically analyzed in few-mode fiber while curvature sensing experiments using multi-core fiber interferometer are performed to verify its excellent performance on vital signs monitoring.The successful demonstration on contactless vital signs monitoring makes few-mode and multi-core fibers promising candidates for healthcare applications.展开更多
Three kinds of Keggin-type titanium-based polyoxometalate-ionic liquid catalysts were prepared,and the chemical structure,crystal structure and thermal stability of the three catalysts were analyzed and tested by infr...Three kinds of Keggin-type titanium-based polyoxometalate-ionic liquid catalysts were prepared,and the chemical structure,crystal structure and thermal stability of the three catalysts were analyzed and tested by infrared spectrometer,ultraviolet-visible spectrometer,X-ray diffractometer,and thermogravimetric analyzer,respectively.Afterwards,their performance in catalyzing the coupling reaction of ethylene carbonate(EC)and dimethyl succinate(DMSu)to synthesize polyethylene succinate(PES)was studied,and the effects of different metals on the catalytic performance and the mechanism of action were discussed.The optimal process parameters for the coupling reaction were explored.Finally,the chemical structure of PES was characterized by infrared spectrometer.The results show that under the same process parameters,the polyoxometalate-ionic liquid catalyst Bmim_(5)[Ti(H_(2)O)TiMo_(11)O_(39)]had the best catalytic effect.Under the optimal process parameters,Bmim_(5)[Ti(H_(2)O)TiMo_(11)O_(39)]had obvious inhibitory effect on side reactions,and the yield and selectivity of PES prepolymer were up to 72.23%and 88.64%.展开更多
Plasmonic resonances empowered by bound states in the continuum(BICs) offer unprecedented opportunities to tailor light–matter interaction. However, excitation of high quality-factor(Q-factor) quasi-BICs is often lim...Plasmonic resonances empowered by bound states in the continuum(BICs) offer unprecedented opportunities to tailor light–matter interaction. However, excitation of high quality-factor(Q-factor) quasi-BICs is often limited to collimated light at specific polarization and incident directions, rendering challenges for unpolarized focused light. The major hurdle is the lack of robustness against weak spatial coherence and poor polarization of incident light. Here, addressing this limitation, we demonstrate sharp resonances in symmetric plasmonic metasurfaces by exploiting BICs in the parameter space, offering ultraweak angular dispersion effect and polarization-independent performance. Specifically, a high-Q(≈71) resonance with near-perfect absorption(>90%) is obtained for the input of unpolarized focused light covering wide incident angles(from 0° to 30°). Also, giant electric and magnetic field enhancement simultaneously occurs in quasi-BICs. These results provide a way to achieve efficient near-field enhancement using focused light produced by high numerical aperture objectives.展开更多
The remarkable capacity of metasurfaces to exert precise control over the propagation of light has ushered in a realm of unprecedented possibilities for"Lab-on-fiber",and in this work,showcased real-time ful...The remarkable capacity of metasurfaces to exert precise control over the propagation of light has ushered in a realm of unprecedented possibilities for"Lab-on-fiber",and in this work,showcased real-time full-color imaging in a meta-optica l fiber endoscope.展开更多
基因组编辑技术(Genomeeditingtechnology)是一种通过人工手段在基因组水平对DNA序列进行改造的遗传操作技术,包括特定DNA片段的插入、敲除、替换和点突变。其中,依赖核酸酶的基因组编辑技术的基本原理是在基因组的特定位置产生双链DNA...基因组编辑技术(Genomeeditingtechnology)是一种通过人工手段在基因组水平对DNA序列进行改造的遗传操作技术,包括特定DNA片段的插入、敲除、替换和点突变。其中,依赖核酸酶的基因组编辑技术的基本原理是在基因组的特定位置产生双链DNA断裂(Double-strandedbreak,DSB)后通过非同源末端连接(Non-homologous end joining,NHEJ)或同源重组(Homologous recombination,HR)的方式进行修复。随着对核酸酶更深入的研究,基因组编辑技术也得到了快速发展,其中最常使用的核酸酶主要包括巨型核酸酶、锌指核酸酶、转录激活因子样效应物核酸酶以及成簇的规律间隔的短回文重复序列相关蛋白(Clusteredregularly interspaced short palindromic repeats(CRISPR)-associated proteins(Cas)。文中在介绍上述基因组编辑技术的发展及作用原理的基础上,主要综述了CRISPR/Cas9系统在基因功能鉴定、疾病模型建立、基因治疗和免疫治疗等应用领域的研究进展,并对其未来发展进行了展望。展开更多
Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods.Orbital angular momentum(OAM)in optical vortex beams offers a new degree of freedom and the pote...Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods.Orbital angular momentum(OAM)in optical vortex beams offers a new degree of freedom and the potential to increase the capacity of free-space optical communication systems,with OAM beams acting as information carriers for OAM division multiplexing(OAM-DM).We demonstrate independent collinear OAM channel generation,transmission and simultaneous detection using Dammann optical vortex gratings(DOVGs).We achieve 80/160 Tbit s^(-1) capacity with uniform power distributions along all channels,with 1600 individually modulated quadrature phase-shift keying(QPSK)/16-QAM data channels multiplexed by 10 OAM states,80 wavelengths and two polarizations.DOVG-enabled OAM multiplexing technology removes the bottleneck of massive OAM state parallel detection and offers an opportunity to raise optical communication systems capacity to Pbit s^(-1) level.展开更多
In this paper,we review our joint timing and frequency synchronization algorithms in coherent optical orthogonal frequency division multiplexing(CO-OFDM)systems.We first present a timing estimation method by designing...In this paper,we review our joint timing and frequency synchronization algorithms in coherent optical orthogonal frequency division multiplexing(CO-OFDM)systems.We first present a timing estimation method by designing the pattern of the training symbol,whose timing metric has a sharp and clear peak,to ensure accurate timing offset(TO)estimation performance.Then we provide both data-aided(DA)and blind(BL)approaches to estimate the carrier frequency offset(CFO).For the DA algorithm,we utilize the same training symbol structure as the timing estimation does,while for the BL algorithm,we utilize the zero-subcarrier power(ZSP)to achieve full-range CFO estimation.Note that our joint timing and frequency synchronization approaches require only one OFDM symbol,which ensure not only the data transmission efficiency,but also the TO and CFO estimation performance.A modified BL ZSP algorithm is proposed to further improve the CFO estimation performance by taking the power average over a series of OFDM symbols.The effectiveness of the TO estimation algorithm,and both the DA and BL CFO estimation algorithms are verified and demonstrated in both simulations and experiments.展开更多
Nanophotonic platforms such as metasurfaces,achieving arbitrary phase profiles within ultrathin thickness,emerge as miniaturized,ultracompact and kaleidoscopic optical vortex generators.However,it is often required to...Nanophotonic platforms such as metasurfaces,achieving arbitrary phase profiles within ultrathin thickness,emerge as miniaturized,ultracompact and kaleidoscopic optical vortex generators.However,it is often required to segment or interleave independent sub-array metasurfaces to multiplex optical vortices in a single nano-device,which in turn affects the device’s compactness and channel capacity.Here,inspired by phyllotaxis patterns in pine cones and sunflowers,we theoretically prove and experimentally report that multiple optical vortices can be produced in a single compact phyllotaxis nanosieve,both in free space and on a chip,where one meta-atom may contribute to many vortices simultaneously.The time-resolved dynamics of on-chip interference wavefronts between multiple plasmonic vortices was revealed by ultrafast time-resolved photoemission electron microscopy.Our nature-inspired optical vortex generator would facilitate various vortex-related optical applications,including structured wavefront shaping,free-space and plasmonic vortices,and high-capacity information metaphotonics.展开更多
A broadband instantaneous multi-frequency measurement system based on chirped pulse compression,which potentially has a sub-megahertz(MHz)accuracy and a hundred-gigahertz(GHz)measurement range,is demonstrated.A signal...A broadband instantaneous multi-frequency measurement system based on chirped pulse compression,which potentially has a sub-megahertz(MHz)accuracy and a hundred-gigahertz(GHz)measurement range,is demonstrated.A signalunder-test(SUT)is converted into a carrier-suppressed double-sideband(CS-DSB)signal,which is then combined with an optical linearly frequency-modulated signal having the sweeping range covering the+1 st-order sideband of the CSDSB signal.With photodetection,low-pass filtering,and pulse compression,accurate frequencies of the SUT are obtained via locating the correlation peaks.In the experiment,single-and multi-frequency measurements with a measurement range from 3 to 18 GHz and a measurement accuracy of<±100 MHz are achieved.展开更多
Dear Editor,Swine major histocompatibility complex(MHC)is a highly polymorphic gene in pigs and is also called swine leukocyte antigen(SLA)(Fan et al.,2018).SLA is divided into three major categories,SLA I(SLA-1,-2,-3...Dear Editor,Swine major histocompatibility complex(MHC)is a highly polymorphic gene in pigs and is also called swine leukocyte antigen(SLA)(Fan et al.,2018).SLA is divided into three major categories,SLA I(SLA-1,-2,-3),SLA II,and SLA III(Smith et al.,2005).SLA I plays an important role in cellular immunity which can eliminate viruses and other foreign antigens in pigs(Macdonald et al.,2010).SLA-1,SLA-2 and SLA-3 are important SLA I alleles and are highly polymorphic.Polymorphism causes extreme difficulties in screening broadly protective cytotoxic lymphocyte(CTL)epitope antigens.The supertype which is built based on peptide-binding specificity of each SLA I can overcome this difficulty to some extent(Thomsen et al.,2013).展开更多
基金The Hong Kong Polytechnic University(1-ZVHA and 1-ZVGB)HK GRC GRF(15211317).
文摘Few-mode and multi-core fibers are proposed and demonstrated for contactless vital signs monitoring in this paper.In-line optical fiber interferometers using few-mode and multi-core fibers are designed and offset splicing is utilized for mode excitation.Extinction ratio and insertion loss are analyzed experimentally under different offset distances.The fabricated in-line interferometers are packaged under the mattress to realize contactless vital signs signals collection.By using filtering techniques,both respiration and heartbeat signals can be recovered successfully,and respiration as well as heartbeat ratio are obtained.Mode excitation and interference are theoretically analyzed in few-mode fiber while curvature sensing experiments using multi-core fiber interferometer are performed to verify its excellent performance on vital signs monitoring.The successful demonstration on contactless vital signs monitoring makes few-mode and multi-core fibers promising candidates for healthcare applications.
基金Supported by the Key Project of Education Department of Liaoning Province(LZGD2020005)。
文摘Three kinds of Keggin-type titanium-based polyoxometalate-ionic liquid catalysts were prepared,and the chemical structure,crystal structure and thermal stability of the three catalysts were analyzed and tested by infrared spectrometer,ultraviolet-visible spectrometer,X-ray diffractometer,and thermogravimetric analyzer,respectively.Afterwards,their performance in catalyzing the coupling reaction of ethylene carbonate(EC)and dimethyl succinate(DMSu)to synthesize polyethylene succinate(PES)was studied,and the effects of different metals on the catalytic performance and the mechanism of action were discussed.The optimal process parameters for the coupling reaction were explored.Finally,the chemical structure of PES was characterized by infrared spectrometer.The results show that under the same process parameters,the polyoxometalate-ionic liquid catalyst Bmim_(5)[Ti(H_(2)O)TiMo_(11)O_(39)]had the best catalytic effect.Under the optimal process parameters,Bmim_(5)[Ti(H_(2)O)TiMo_(11)O_(39)]had obvious inhibitory effect on side reactions,and the yield and selectivity of PES prepolymer were up to 72.23%and 88.64%.
基金Research Grants Council,University Grants Committee(15209321,15303521,11310522,and Ao E/P-502/20)Beijing-Hong Kong Universities Alliance(BHUA)fund+3 种基金Germany/Hong Kong Joint Research Scheme 2022/23(9053045)Shenzhen Science and Technology Innovation Program(SGDX2019081623281169)Guangdong Science and Technology Department(2020B1515120073)City University of Hong Kong(9380131)
文摘Plasmonic resonances empowered by bound states in the continuum(BICs) offer unprecedented opportunities to tailor light–matter interaction. However, excitation of high quality-factor(Q-factor) quasi-BICs is often limited to collimated light at specific polarization and incident directions, rendering challenges for unpolarized focused light. The major hurdle is the lack of robustness against weak spatial coherence and poor polarization of incident light. Here, addressing this limitation, we demonstrate sharp resonances in symmetric plasmonic metasurfaces by exploiting BICs in the parameter space, offering ultraweak angular dispersion effect and polarization-independent performance. Specifically, a high-Q(≈71) resonance with near-perfect absorption(>90%) is obtained for the input of unpolarized focused light covering wide incident angles(from 0° to 30°). Also, giant electric and magnetic field enhancement simultaneously occurs in quasi-BICs. These results provide a way to achieve efficient near-field enhancement using focused light produced by high numerical aperture objectives.
文摘The remarkable capacity of metasurfaces to exert precise control over the propagation of light has ushered in a realm of unprecedented possibilities for"Lab-on-fiber",and in this work,showcased real-time full-color imaging in a meta-optica l fiber endoscope.
文摘基因组编辑技术(Genomeeditingtechnology)是一种通过人工手段在基因组水平对DNA序列进行改造的遗传操作技术,包括特定DNA片段的插入、敲除、替换和点突变。其中,依赖核酸酶的基因组编辑技术的基本原理是在基因组的特定位置产生双链DNA断裂(Double-strandedbreak,DSB)后通过非同源末端连接(Non-homologous end joining,NHEJ)或同源重组(Homologous recombination,HR)的方式进行修复。随着对核酸酶更深入的研究,基因组编辑技术也得到了快速发展,其中最常使用的核酸酶主要包括巨型核酸酶、锌指核酸酶、转录激活因子样效应物核酸酶以及成簇的规律间隔的短回文重复序列相关蛋白(Clusteredregularly interspaced short palindromic repeats(CRISPR)-associated proteins(Cas)。文中在介绍上述基因组编辑技术的发展及作用原理的基础上,主要综述了CRISPR/Cas9系统在基因功能鉴定、疾病模型建立、基因治疗和免疫治疗等应用领域的研究进展,并对其未来发展进行了展望。
基金This work was partially supported by the National Natural Science Foundation of China under Grant numbers 61036013,61138003,61427819,61001101 and 61435006XY acknowledges support from the Ministry of Science and Technology of China under National Basic Research Program of China(973)grant no.2015CB352004.
文摘Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods.Orbital angular momentum(OAM)in optical vortex beams offers a new degree of freedom and the potential to increase the capacity of free-space optical communication systems,with OAM beams acting as information carriers for OAM division multiplexing(OAM-DM).We demonstrate independent collinear OAM channel generation,transmission and simultaneous detection using Dammann optical vortex gratings(DOVGs).We achieve 80/160 Tbit s^(-1) capacity with uniform power distributions along all channels,with 1600 individually modulated quadrature phase-shift keying(QPSK)/16-QAM data channels multiplexed by 10 OAM states,80 wavelengths and two polarizations.DOVG-enabled OAM multiplexing technology removes the bottleneck of massive OAM state parallel detection and offers an opportunity to raise optical communication systems capacity to Pbit s^(-1) level.
文摘In this paper,we review our joint timing and frequency synchronization algorithms in coherent optical orthogonal frequency division multiplexing(CO-OFDM)systems.We first present a timing estimation method by designing the pattern of the training symbol,whose timing metric has a sharp and clear peak,to ensure accurate timing offset(TO)estimation performance.Then we provide both data-aided(DA)and blind(BL)approaches to estimate the carrier frequency offset(CFO).For the DA algorithm,we utilize the same training symbol structure as the timing estimation does,while for the BL algorithm,we utilize the zero-subcarrier power(ZSP)to achieve full-range CFO estimation.Note that our joint timing and frequency synchronization approaches require only one OFDM symbol,which ensure not only the data transmission efficiency,but also the TO and CFO estimation performance.A modified BL ZSP algorithm is proposed to further improve the CFO estimation performance by taking the power average over a series of OFDM symbols.The effectiveness of the TO estimation algorithm,and both the DA and BL CFO estimation algorithms are verified and demonstrated in both simulations and experiments.
基金supported by the National Research Foundation,Prime Minister’s Office,Singapore under Competitive Research Program Award NRF-CRP22-2019-0006the grant(R-261-518-004-720)from Advanced Research and Technology Innovation Centre(ARTIC)+4 种基金the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-Project-ID 278162697-SFB 1242ERC Advanced Grant Complex Plan,BMBF,DFG and BW-Stiftungthe Research Grants Council of Hong Kong(CRF Grant No.C6013-18G)the City University of Hong Kong(Project No.9610434)the support from A*STAR under its AME YIRG Grant(Award No.A2084c0172).
文摘Nanophotonic platforms such as metasurfaces,achieving arbitrary phase profiles within ultrathin thickness,emerge as miniaturized,ultracompact and kaleidoscopic optical vortex generators.However,it is often required to segment or interleave independent sub-array metasurfaces to multiplex optical vortices in a single nano-device,which in turn affects the device’s compactness and channel capacity.Here,inspired by phyllotaxis patterns in pine cones and sunflowers,we theoretically prove and experimentally report that multiple optical vortices can be produced in a single compact phyllotaxis nanosieve,both in free space and on a chip,where one meta-atom may contribute to many vortices simultaneously.The time-resolved dynamics of on-chip interference wavefronts between multiple plasmonic vortices was revealed by ultrafast time-resolved photoemission electron microscopy.Our nature-inspired optical vortex generator would facilitate various vortex-related optical applications,including structured wavefront shaping,free-space and plasmonic vortices,and high-capacity information metaphotonics.
基金supported in part by the Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.KYLX16_0367)the National Natural Science Foundation of China(Nos.62071226 and 61971372)+1 种基金the Hong Kong Scholar Program(No.G-YZ2S)HK RGC GRF(No.15200718)。
文摘A broadband instantaneous multi-frequency measurement system based on chirped pulse compression,which potentially has a sub-megahertz(MHz)accuracy and a hundred-gigahertz(GHz)measurement range,is demonstrated.A signalunder-test(SUT)is converted into a carrier-suppressed double-sideband(CS-DSB)signal,which is then combined with an optical linearly frequency-modulated signal having the sweeping range covering the+1 st-order sideband of the CSDSB signal.With photodetection,low-pass filtering,and pulse compression,accurate frequencies of the SUT are obtained via locating the correlation peaks.In the experiment,single-and multi-frequency measurements with a measurement range from 3 to 18 GHz and a measurement accuracy of<±100 MHz are achieved.
基金Financed by the National Key R&D Program of China(2017YFD0502302)National 12th Five-Year Plan Science and Technology Support Project(2015BAD12B01-06).
文摘Dear Editor,Swine major histocompatibility complex(MHC)is a highly polymorphic gene in pigs and is also called swine leukocyte antigen(SLA)(Fan et al.,2018).SLA is divided into three major categories,SLA I(SLA-1,-2,-3),SLA II,and SLA III(Smith et al.,2005).SLA I plays an important role in cellular immunity which can eliminate viruses and other foreign antigens in pigs(Macdonald et al.,2010).SLA-1,SLA-2 and SLA-3 are important SLA I alleles and are highly polymorphic.Polymorphism causes extreme difficulties in screening broadly protective cytotoxic lymphocyte(CTL)epitope antigens.The supertype which is built based on peptide-binding specificity of each SLA I can overcome this difficulty to some extent(Thomsen et al.,2013).
