Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scat...Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scattering characteristics can enable the wireless ultraviolet communication system to transmit ultraviolet light signals in a non-line-of-sight manner, which overcomes the weakness that other free space optical communications must work in a line-of-sight manner. Based on the basic theory of scattering and absorption in atmospheric optics, taking the ultraviolet light with a wavelength of 266 nm as an example, this paper introduces the classical model of non-line-of-sight single-scattering coplanarity based on the ellipsoid coordinate system. The model is used to simulate and analyze the relationship between the geometric parameters such as transmission distance, transceiver elevation angle and transceiver half-angle and the received optical power per unit area. The performance of non-line-of-sight ultraviolet communication system in rain and fog environment is discussed respectively. The results show that the transmission quality of non-line-of-sight ultraviolet atmospheric propagation is greatly affected by the communication distance. As the distance increases, the received light power per unit area gradually decreases. In addition, increasing the emission elevation angle, the receiving elevation angle and the receiving half angle is an important way to improve the system performance.展开更多
With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar backgro...With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar background noise, non-line-of-sight(NLOS) and good secrecy. The strong scattering characteristics in atmospheric render ultraviolet waveband the ideal choice for achieving NLOS optical communication. This paper reviews the research history and status of ultraviolet communication both in China and abroad, and especially introduces three main issues of ultraviolet communication: channel model, system analysis and design, light sources and detectors. For each aspect, current open issues and prospective research directions are analyzed.展开更多
Non-Line-of-Sight(NLOS)Ultraviolet(UV)communication uses the atmosphere as a propagation medium.As the communication range increases,turbulence becomes a significant atmospheric process that affects the propagation of...Non-Line-of-Sight(NLOS)Ultraviolet(UV)communication uses the atmosphere as a propagation medium.As the communication range increases,turbulence becomes a significant atmospheric process that affects the propagation of optical waves.This paper presents a more accurate NLOS channel model by considering turbulence-induced Scintillation Attenuation(SA).Then,the Bit Error Rate(BER)during turbulence of the NLOS UV communication system with On-Off Keying(OOK)modulation and Maximum Likelihood(ML)detection is analysed and compared with that in free space without turbulence.The BER dependence is also analysed for different factors,including the refractive index structure parameter,transceiver range,pointing angles,transmitted power,and data rate.展开更多
With recent developments of deep ultraviolet(DUV)light-emitting diodes and solar-blind detectors,UV communication(UVC)shows great potential in replacing traditional wireless communication in more and more scenarios.Ba...With recent developments of deep ultraviolet(DUV)light-emitting diodes and solar-blind detectors,UV communication(UVC)shows great potential in replacing traditional wireless communication in more and more scenarios.Based on the atmospheric scattering of UV radiation,UVC has gained considerable attention due to its non-line-of-sight ability,omnidirectional communication links and low background noise.These advantages make UVC an ideal option for covert secure communication,especially for military communication.In this review,we present the history and working principle of UVC with a special focus on its light sources and detectors.Comprehensive comparison and application of its light sources and detectors are provided to the best of our knowledge.We further discuss the future application and outlook of UVC.Hopefully,this review will offer valuable insights into the future development of UVC.展开更多
Two strains H2-410 and H2-419 were obtained from the chemically mutated survivors of wild Haematococcus pluvialis 2 by using ethyl methanesulphonate (EMS). Strains H2-410 and H2-419 showed a fast cell growth with 13% ...Two strains H2-410 and H2-419 were obtained from the chemically mutated survivors of wild Haematococcus pluvialis 2 by using ethyl methanesulphonate (EMS). Strains H2-410 and H2-419 showed a fast cell growth with 13% and 20% increase in biomass compared to wild type, respectively. Then H2-419-4, a fast cell growth and high astaxanthin accumulation strain, was obtained by exposing the strain H2-419 to ultraviolet radiation (UV) further. The total biomass, the astaxanthin content per cell, astaxanthin production of H2-419-4 showed 68%, 28%, and 120% increase compared to wild H. pluvialis 2, respectively. HPLC (High Performance Liquid Chromatography) data showed also an obvious proportional variation of different carotenoid compositions in the extracts of H2-419-4 and the wild type, although no peak of carotenoids appeared or disappeared. Therefore, the main compositions in strain H2-419-4, like its wild one, were free of astaxanthin, monoester, and diester of astaxanthin. The asexual reproduction in survivors after exposed to UV was not synchronous, and different from the normal synchronous asexual reproduction as the mother cells were motile instead of non-motile. Interestingly, some survivors from UV irradiation produced many mini-spores (or gamete?), the spores moved away from the mother cell gradually 4 or 5 days later. This is quite similar to sexual reproduction described by Elliot in 1934. However, whether this was sexual reproduction remains questionable, as no mating process has been observed.展开更多
<div style="text-align:justify;"> In the channel estimation for ultraviolet communication, the single scattering power is usually used to approximate the received total power. This approximation error ...<div style="text-align:justify;"> In the channel estimation for ultraviolet communication, the single scattering power is usually used to approximate the received total power. This approximation error is affected by the transceiver configuration. Here, we employ the proportion of received single scattering power in received total power to indicate the approximation error of the single scattering model in different configurations. This is useful for reducing the approximation error by selecting a more appropriate transceiver configuration. </div>展开更多
A 300 kbps wide-angle non-line-of-sight ultraviolet communication system with voice transmission function is designed here.Based on Poisson distribution theory,we design the symbol detecting method for the receiving d...A 300 kbps wide-angle non-line-of-sight ultraviolet communication system with voice transmission function is designed here.Based on Poisson distribution theory,we design the symbol detecting method for the receiving discrete photon signals.Using 272 nm LED array as the light source and PMT as the detector,the voice transceiver is integrated into the carriable size of 200×90×65 mm^(3).An outfield test shows the system obtains the BER of 0.88% under 200 m.Under 10°wide-angle deviation of the transmitter,a BER below 1.33% is achieved.展开更多
The ultraviolet (UV) photoresponses of Wurtzite GaN, ZnO, and 6H-SiC-based Optical Field Effect Transistor (OPFET) detectors are estimated with an in-depth analysis of the same considering the generalized model and th...The ultraviolet (UV) photoresponses of Wurtzite GaN, ZnO, and 6H-SiC-based Optical Field Effect Transistor (OPFET) detectors are estimated with an in-depth analysis of the same considering the generalized model and the front-illuminated model for high resolution imaging and UV communication applications. The gate materials considered for the proposed study are gold (Au) and Indium-Tin-Oxide (ITO) for GaN, Au for SiC, and Au and silver dioxide (AgO2) for ZnO. The results indicate significant improvement in the Linear Dynamic Range (LDR) over the previously investigated GaN OPFET (buried-gate, front-illuminated and generalized) models with Au gate. The generalized model has superior dynamic range than the front-illuminated model. In terms of responsivity, all the models including buried-gate OPFET exhibit high and comparable photoresponses. Buried-gate devices on the whole, exhibit faster response than the surface gate models except in the AgO2-ZnO generalized OPFET model wherein the switching time is the lowest. The generalized model enables faster switching than the front-illuminated model. The switching times in all the cases are of the order of nanoseconds to picoseconds. The SiC generalized OPFET model shows the highest 3-dB bandwidths of 11.88 GHz, 36.2 GHz, and 364 GHz, and modest unity-gain cut-off frequencies of 4.62 GHz, 8.71 GHz, and 5.71 GHz at the optical power densities of 0.575 μW/cm2, 0.575 mW/cm2, and 0.575 W/cm2 respectively. These are in overall, the highest detection-cum-amplifi-cation bandwidths among all the investigated devices. The same device exhibits the highest LDR of 73.3 dB. The device performance is superior to most of the other existing detectors along with comparable LDR, thus, emerging as a high performance photodetector for imaging and communication applications. All the detectors show considerably high detectivities owing to the high responsivity values. The results have been analyzed by the photovoltaic and the photoconductive effects, and the series resistance effects and will aid in conducting further research. The results are in line with the experiments and the commercially available software simulations. The devices will greatly contribute towards single photon counting, high resolution imaging, and UV communication applications.展开更多
Ultraviolet （UV） aging is one of the main factors which cause premature damage of asphalt pavements in the Tibetan Plateau, China. According to the measured levels of UV radiation, aging tests of styrene-butadiene r...Ultraviolet （UV） aging is one of the main factors which cause premature damage of asphalt pavements in the Tibetan Plateau, China. According to the measured levels of UV radiation, aging tests of styrene-butadiene rubber （SBR） asphalts with different contents of three anti-UV-aging agents including nano-TiO2, CeO2 and carbon black are performed. Common indices, which include retained penetration after thin film oven tests （TFOT） and softening point, and strategic highway research program （SHRP） indices of aged asphalts are evaluated. Infrared absorption spectral analysis is performed on asphalt specimens with 0. 8% carbon black which have been aged for different aging times （500, 1000 and 1 500 h）. By grey incidence analysis, the optimal contents of anti-UV-aging agents are determined. The results show that TiO2 and CeO2 are not only good UV absorbing or shielding agents, but also strong oxidants. Carbon black is a good anti-UV-aging agent, and its optimal content is about 0. 8% of asphalt weight. UV aging of asphalt mainly occurs in the early stages of aging. The longer the aging time, the more severe the aging of asphalt.展开更多
文摘Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scattering characteristics can enable the wireless ultraviolet communication system to transmit ultraviolet light signals in a non-line-of-sight manner, which overcomes the weakness that other free space optical communications must work in a line-of-sight manner. Based on the basic theory of scattering and absorption in atmospheric optics, taking the ultraviolet light with a wavelength of 266 nm as an example, this paper introduces the classical model of non-line-of-sight single-scattering coplanarity based on the ellipsoid coordinate system. The model is used to simulate and analyze the relationship between the geometric parameters such as transmission distance, transceiver elevation angle and transceiver half-angle and the received optical power per unit area. The performance of non-line-of-sight ultraviolet communication system in rain and fog environment is discussed respectively. The results show that the transmission quality of non-line-of-sight ultraviolet atmospheric propagation is greatly affected by the communication distance. As the distance increases, the received light power per unit area gradually decreases. In addition, increasing the emission elevation angle, the receiving elevation angle and the receiving half angle is an important way to improve the system performance.
基金supported by the National High-tech R&D Program of China grant 2015AA043302the Basic research project of Shenzhen grant JCYJ20140417115840236
文摘With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar background noise, non-line-of-sight(NLOS) and good secrecy. The strong scattering characteristics in atmospheric render ultraviolet waveband the ideal choice for achieving NLOS optical communication. This paper reviews the research history and status of ultraviolet communication both in China and abroad, and especially introduces three main issues of ultraviolet communication: channel model, system analysis and design, light sources and detectors. For each aspect, current open issues and prospective research directions are analyzed.
基金supported by the Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),China
文摘Non-Line-of-Sight(NLOS)Ultraviolet(UV)communication uses the atmosphere as a propagation medium.As the communication range increases,turbulence becomes a significant atmospheric process that affects the propagation of optical waves.This paper presents a more accurate NLOS channel model by considering turbulence-induced Scintillation Attenuation(SA).Then,the Bit Error Rate(BER)during turbulence of the NLOS UV communication system with On-Off Keying(OOK)modulation and Maximum Likelihood(ML)detection is analysed and compared with that in free space without turbulence.The BER dependence is also analysed for different factors,including the refractive index structure parameter,transceiver range,pointing angles,transmitted power,and data rate.
基金financially supported by the National Key R&D Program of China(No.2019YFA0708203)the National Natural Science Foundation of China(No.61974139)the Beijing Natural Science Foundation(No.4182063)。
文摘With recent developments of deep ultraviolet(DUV)light-emitting diodes and solar-blind detectors,UV communication(UVC)shows great potential in replacing traditional wireless communication in more and more scenarios.Based on the atmospheric scattering of UV radiation,UVC has gained considerable attention due to its non-line-of-sight ability,omnidirectional communication links and low background noise.These advantages make UVC an ideal option for covert secure communication,especially for military communication.In this review,we present the history and working principle of UVC with a special focus on its light sources and detectors.Comprehensive comparison and application of its light sources and detectors are provided to the best of our knowledge.We further discuss the future application and outlook of UVC.Hopefully,this review will offer valuable insights into the future development of UVC.
基金the Innovation Program of the Institute of Oceanology,CAS (No.L86032523)the Project of Ministry of Sciences and Technology of China (No.02EFN216601213)
文摘Two strains H2-410 and H2-419 were obtained from the chemically mutated survivors of wild Haematococcus pluvialis 2 by using ethyl methanesulphonate (EMS). Strains H2-410 and H2-419 showed a fast cell growth with 13% and 20% increase in biomass compared to wild type, respectively. Then H2-419-4, a fast cell growth and high astaxanthin accumulation strain, was obtained by exposing the strain H2-419 to ultraviolet radiation (UV) further. The total biomass, the astaxanthin content per cell, astaxanthin production of H2-419-4 showed 68%, 28%, and 120% increase compared to wild H. pluvialis 2, respectively. HPLC (High Performance Liquid Chromatography) data showed also an obvious proportional variation of different carotenoid compositions in the extracts of H2-419-4 and the wild type, although no peak of carotenoids appeared or disappeared. Therefore, the main compositions in strain H2-419-4, like its wild one, were free of astaxanthin, monoester, and diester of astaxanthin. The asexual reproduction in survivors after exposed to UV was not synchronous, and different from the normal synchronous asexual reproduction as the mother cells were motile instead of non-motile. Interestingly, some survivors from UV irradiation produced many mini-spores (or gamete?), the spores moved away from the mother cell gradually 4 or 5 days later. This is quite similar to sexual reproduction described by Elliot in 1934. However, whether this was sexual reproduction remains questionable, as no mating process has been observed.
文摘<div style="text-align:justify;"> In the channel estimation for ultraviolet communication, the single scattering power is usually used to approximate the received total power. This approximation error is affected by the transceiver configuration. Here, we employ the proportion of received single scattering power in received total power to indicate the approximation error of the single scattering model in different configurations. This is useful for reducing the approximation error by selecting a more appropriate transceiver configuration. </div>
基金the National Key R&D Program of China under Grant 2019YFB2203700in part by the National Nature Science Fund of China under Grants 61527820 and 61625504.
文摘A 300 kbps wide-angle non-line-of-sight ultraviolet communication system with voice transmission function is designed here.Based on Poisson distribution theory,we design the symbol detecting method for the receiving discrete photon signals.Using 272 nm LED array as the light source and PMT as the detector,the voice transceiver is integrated into the carriable size of 200×90×65 mm^(3).An outfield test shows the system obtains the BER of 0.88% under 200 m.Under 10°wide-angle deviation of the transmitter,a BER below 1.33% is achieved.
文摘The ultraviolet (UV) photoresponses of Wurtzite GaN, ZnO, and 6H-SiC-based Optical Field Effect Transistor (OPFET) detectors are estimated with an in-depth analysis of the same considering the generalized model and the front-illuminated model for high resolution imaging and UV communication applications. The gate materials considered for the proposed study are gold (Au) and Indium-Tin-Oxide (ITO) for GaN, Au for SiC, and Au and silver dioxide (AgO2) for ZnO. The results indicate significant improvement in the Linear Dynamic Range (LDR) over the previously investigated GaN OPFET (buried-gate, front-illuminated and generalized) models with Au gate. The generalized model has superior dynamic range than the front-illuminated model. In terms of responsivity, all the models including buried-gate OPFET exhibit high and comparable photoresponses. Buried-gate devices on the whole, exhibit faster response than the surface gate models except in the AgO2-ZnO generalized OPFET model wherein the switching time is the lowest. The generalized model enables faster switching than the front-illuminated model. The switching times in all the cases are of the order of nanoseconds to picoseconds. The SiC generalized OPFET model shows the highest 3-dB bandwidths of 11.88 GHz, 36.2 GHz, and 364 GHz, and modest unity-gain cut-off frequencies of 4.62 GHz, 8.71 GHz, and 5.71 GHz at the optical power densities of 0.575 μW/cm2, 0.575 mW/cm2, and 0.575 W/cm2 respectively. These are in overall, the highest detection-cum-amplifi-cation bandwidths among all the investigated devices. The same device exhibits the highest LDR of 73.3 dB. The device performance is superior to most of the other existing detectors along with comparable LDR, thus, emerging as a high performance photodetector for imaging and communication applications. All the detectors show considerably high detectivities owing to the high responsivity values. The results have been analyzed by the photovoltaic and the photoconductive effects, and the series resistance effects and will aid in conducting further research. The results are in line with the experiments and the commercially available software simulations. The devices will greatly contribute towards single photon counting, high resolution imaging, and UV communication applications.
文摘Ultraviolet （UV） aging is one of the main factors which cause premature damage of asphalt pavements in the Tibetan Plateau, China. According to the measured levels of UV radiation, aging tests of styrene-butadiene rubber （SBR） asphalts with different contents of three anti-UV-aging agents including nano-TiO2, CeO2 and carbon black are performed. Common indices, which include retained penetration after thin film oven tests （TFOT） and softening point, and strategic highway research program （SHRP） indices of aged asphalts are evaluated. Infrared absorption spectral analysis is performed on asphalt specimens with 0. 8% carbon black which have been aged for different aging times （500, 1000 and 1 500 h）. By grey incidence analysis, the optimal contents of anti-UV-aging agents are determined. The results show that TiO2 and CeO2 are not only good UV absorbing or shielding agents, but also strong oxidants. Carbon black is a good anti-UV-aging agent, and its optimal content is about 0. 8% of asphalt weight. UV aging of asphalt mainly occurs in the early stages of aging. The longer the aging time, the more severe the aging of asphalt.
