High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in detail.Theκ(ε)-Ga_(2)O_(3)layers were ...High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in detail.Theκ(ε)-Ga_(2)O_(3)layers were deposited by the halide vapor phase epitaxy on patterned GaN templates with sapphire substrates.The spectral dependencies of the photoelectric properties of struc-tures were analyzed in the wavelength interval 200-370 nm.The maximum photo to dark current ratio,responsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 arb.un.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,respectively,at a wavelength of 200 nm and an applied voltage of 1 V.The enhancement of the photoresponse was caused by the decrease in the Schottky barrier at the Pt/κ(ε)-Ga_(2)O_(3)interface under ultraviolet exposure.The detectors demon-strated could functionalize in self-powered mode due to built-in electric field at the Pt/κ(ε)-Ga_(2)O_(3)interface.The responsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero applied voltage were 0.9 mA/W and 0.46%,respectively.The rise and decay times in self-powered mode did not exceed 100 ms.展开更多
This review describes the effects of ultraviolet-B (UV-B) radiation on plant growth and development, photosynthesis and photosynthetic pigments and UV-B absorbing compounds. Moreover, plant ecosystem level responses...This review describes the effects of ultraviolet-B (UV-B) radiation on plant growth and development, photosynthesis and photosynthetic pigments and UV-B absorbing compounds. Moreover, plant ecosystem level responses to elevated UV-B radiation and interactions of UV-B radiation with abiotic and biotic factors were also involved. Results collected in this review suggest that approximately two-thirds terrestrial plant species are significantly affected by increase in UV-B radiation, The majority of evidences indicate that elevated UV-B radiation is usually detrimental but there exists tremendous variability in the sensitivity of species to UV-B radiation, and sensitivity also differs among cultivars of the same species.展开更多
In order to investigate the protective effect of aloe anthraquinones on growth and development of soybean against ultraviolet B radiation stress from the morphological structure and physio-chemical indices. The result...In order to investigate the protective effect of aloe anthraquinones on growth and development of soybean against ultraviolet B radiation stress from the morphological structure and physio-chemical indices. The results showed that, stressed by the enhanced ultraviolet b radiation, the soybean gave a dwarfed plant, shrunken leaf area and decreased photosynthetic pigment, while an ascended MDA content. Spraying aloe anthraquinones effectively relieved the reductions of chloro- phyll content and biomass and decreased the production of MDA under the radia- tion of UV-B. Moreover, under the UV-B radiation, waxy substances on epidermal cells increased remarkably and the stomas showed obvious subsidence, while spraying aloe anthraquinones could maintain the structure and shape of cells similar to that under natural light, and the stomas subsidence as well.展开更多
A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a...A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors.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
Polytetrafluoroethylene (Teflon), a widely used spacecraft material, isstudied to investigate the vacuum ultraviolet (VUV) effects and its synergistic effects with atomicoxygen (AO) in a ground-based simulation facili...Polytetrafluoroethylene (Teflon), a widely used spacecraft material, isstudied to investigate the vacuum ultraviolet (VUV) effects and its synergistic effects with atomicoxygen (AO) in a ground-based simulation facility. The samples before and after the experiments arecompared in appearance, mass, optical properties and surface composition. The reactioncharacteristics of Teflon are summarized and the reaction mechanisms are analyzed. The followingconclusion can be drawn: at the action of VUV the Teflon sample surface is darkened for theaccumulation of carbon; and when the sample is exposed to AO, the carbon is oxidized and thedarkening surface is bleached; the synergistic effects of VUV and AO may cause the erosion of Teflonmore severe.展开更多
Seven hundred and twenty one-day-old AA broiler chickens were randomly allocated into two groups (male and female for half), and put into two identical closed houses with different lighting programs. The first house...Seven hundred and twenty one-day-old AA broiler chickens were randomly allocated into two groups (male and female for half), and put into two identical closed houses with different lighting programs. The first house was illuminated by using common incandescence light, and the second one was added with ultraviolet radiation light from the second week onwards. The birds lived in a floor with litters and free access to feed and water. Temperature, humidity and immune programs in the two houses were similar. The results showed that under ultraviolet radiation, the growth speed of skeleton increased (the shank length was significantly increased in the third week, P〈0.05; the leg muscle weight was significantly improved by 3.87%, P〈 0.05); the skeleton quality improved (the density of skeleton mineralization was significantly increased by 6.11%, P 〈 0.01; serum calcium, phosphorus, and alkaline phosphatase activity were all improved); and the growth performance was improved (feed conversion ratio was improved by 1.4% averagely; the uniformity of body weight, the shank length, the inclined body length and body height were significantly improved) in broiler chicken.展开更多
Objective Solar ultraviolet (UV) radiation is an important environmental factor that affects human health. The understanding of diurnal variations of UV radiation at anatomical sites may be helpful in developing way...Objective Solar ultraviolet (UV) radiation is an important environmental factor that affects human health. The understanding of diurnal variations of UV radiation at anatomical sites may be helpful in developing ways to protect humans from the harmful effects of UV radiation. Methods In order to characterize the diurnal variations, the UV exposure values were measured at 30 min intervals by using Solar-UV Sensors and a rotating manikin in Shenyang city of China (41°51'N, 123°27%). Measurement data for four representative days (in each of the four seasons respectively) were analyzed. Results The diurnal variations in solar UV radiation at the shoulder, the forehead and the chest were similar to those associated with a horizontal control measurement. However, the diurnal variations at the eye and the cheek exhibited bimodal distributions with two peaks in spring, summer and autumn, and a unimodal distribution in winter. The UV exposure peaks at the eye and the cheek were measured at solar elevation angles (SEA) of about 30° and 40°, respectively. Conclusion The protection of some anatomical sites such as the eye from high UV exposure should not be focused solely on the periods before and after noon, especially in the places and seasons with high SEA.展开更多
Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ...Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ultraviolet A (UVA) and ultraviolet B (UVB) radiation. The chronic ultraviolet irradiated guinea pig model was established, and visible changes in the skin including wrinkling, sagging and erythema were observed. Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH px) in the dorsal skin were determined using biochemical methods. The results showed:(1)PCF (5 % and 20%) could greatly protect the dorsal skin of guinea pig against wrinkling, sagging and erythema induced by UV radiation in a concentration dependent manner.(2)PCF could reduce MDA formation in the dorsal skin caused by UV irradiation, while increasing the activities of SOD and GSH px.(3)The differences among the PCF groups and UV model group were significant ( P <0.05, P <0.01). These results indicated that topical application of PCF provided broad solar UV spectrum photoprotection; and that the antioxidant property of PCF might play a role in photoprotection.展开更多
Vacuum ultraviolet radiation of Upilex-S polyimide film 25 μm thick was performed using a gas jet type of vacuum ultraviolet simulator which gives unfixed wavelength from 5 nm to 200 nm.Nanoparticles redeposited on t...Vacuum ultraviolet radiation of Upilex-S polyimide film 25 μm thick was performed using a gas jet type of vacuum ultraviolet simulator which gives unfixed wavelength from 5 nm to 200 nm.Nanoparticles redeposited on the films were observed and the nanoparticles formed on the surface consist mainly of carbon clusters.Changes in the composition and the chemical characteristics of film surface after radiation were identified by X-ray photoelectron spectroscopy(XPS).Relative O content in the radiated area was found to be higher,while N content was lower than in the pristine area.This indicates that Upilex-S polyimide film releases N atoms as volatile species.And the C1s,O1s envelopes were fitted using Multipak Spectrum software.The surface morphologies on iradiated area were examined by Atomic Force Microscope(AFM).Pieces of radiant products protrude from the eradiated surface,leading to considerable roughness for the iradiated area.And the surface transmittance of Upilex-S film after radiation reduces.展开更多
The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were stu...The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were studied in dinoflag-ellate Prorocentrum lima cultured outdoors for 16 days and indoors for 18 days.In the outdoor experiment,UVA radiation(320-400 nm)increased the growth rate of this dinoflagellate when solar light intensities were<12%;decreased growth rates were observed when intensities were>12%.Exposure to UVB radiation(280-320 nm)alleviated the negative effects of UVA.In the indoor ex-periment,UVA and low doses of UVB enhanced growth rates.Addition of low doses of UVB to UVA exposure resulted in higher contents of Chl a and photoprotective pigments compared with UVA exposure only.The results of both experiments showed that UVB is the primary signal of UVAC synthesis.High-dose UVB exposure accelerated growth rates when UVAC contents were maintained at high levels,suggesting that the latter plays a key role in UVR damage protection.Furthermore,the repair rate was en-hanced by UVB exposure after 16 days of culture.This study confirms the positive effects of UVA and UVB on the growth of P.lima,with the latter enhancing the photoprotective and recovery pathways of the species.展开更多
Ultraviolet (UV) radiation has a significant influence on marine biological processes and primary productivity; however, the existing ocean color satellite sensors seldom contain UV bands. A look-up table of wavelen...Ultraviolet (UV) radiation has a significant influence on marine biological processes and primary productivity; however, the existing ocean color satellite sensors seldom contain UV bands. A look-up table of wavelength- integrated UV irradiance (280-400 nm) on the sea surface is established using the coupled ocean atmosphere radiative transfer (COART) model. On the basis of the look-up table, the distributions of the UV irradiance at middle and low latitudes are inversed by using the satellite-derived atmospheric products from the Aqua satellite, including aerosol optical thickness at 550 nm, ozone content, liquid water path, and the total precipitable water. The validation results show that the mean relative difference of the 10 d rolling averaged UV irradiance between the satellite retrieval and field observations is 8.20% at the time of satellite passing and 13.95% for the daily dose of UV. The monthly-averaged UV irradiance and daily dose of UV retrieved by satellite data show a good correlation with the in situ data, with mean relative differences of 6.87% and 8.43%, respectively. The sensitivity analysis of satellite inputs is conducted. The liquid water path representing the condition of cloud has the highest effect on the retrieval of the UV irradiance, while ozone and aerosol have relatively lesser effect. The influence of the total precipitable water is not significant. On the basis of the satellite-derived UV irradiance on the sea surface, a preliminary simple estimation of ultraviolet radiation's effects on the global marine primary productivity is presented, and the results reveal that ultraviolet radiation has a non-negligible effect on the estimation of the marine primary productivity.展开更多
Objective This work explores the diurnal variation of Solar ultraviolet radiation (UVR) and total solar radiation (TSR) in northeast China,using daily observations of UVR and TSR in Shenyang.Methods UVR and TSR me...Objective This work explores the diurnal variation of Solar ultraviolet radiation (UVR) and total solar radiation (TSR) in northeast China,using daily observations of UVR and TSR in Shenyang.Methods UVR and TSR measurements were carried out from March 1st,2006 to December 31st,2009 in Shenyang,Liaoning province,China (41°51' N,123°27' E).Results Both TSR and UVR showed seasonal variation,reaching the highest levels in summer and the lowest in winter.They showed the greatest fluctuation in summer and autumn.The irradiance of TSR and UVR on clear days around the equinoxes and solstices increased substantially compared with the mean seasonal irradiance,especially in autumn.The whole day accumulated dose of UVR in winter was far less than that during the middle part of a summer day (i.e.between 10:00 and 14:00).It was also less than the accumulated summer dose of morning and afternoon (i.e.between 8:00 and 10:00 and 14:00 and 16:00).Conclusion The instant irradiance and daily accumulated amount of UVR are low in Shenyang,especially in autumn and winter.Thus concern about the health effects arising because shortage of UVR in northeast China is warranted.展开更多
Polysiloxane/SiO2 hybrid coatings have been prepared on Kapton films by a sol-gel process. The erosion resistance of polysiloxane/Si02 (20 wt pct) coating was evaluated by exposure tests of vacuum ultraviolet radiat...Polysiloxane/SiO2 hybrid coatings have been prepared on Kapton films by a sol-gel process. The erosion resistance of polysiloxane/Si02 (20 wt pct) coating was evaluated by exposure tests of vacuum ultraviolet radiation (VUV) and atomic oxygen beam (AO) in a ground-based simulation facility. The experimental results indicate that this coating exhibits better AO resistance than pure polysiloxane coating. The erosion yield (Ey) of the polysiloxane/Si02 (20 wt pct) hybrid coating is about 10-27 cm3/atom, being one or two orders of magnitude lower than that of polysiloxane. VUV radiation can affect the erosion process greatly. Under simultaneous AO and VUV exposure, the value of Ey of the polysiloxane/5iO2 (20 wt pct) hybrid coating increases by 3g% compared with that under single AO exposure.展开更多
According to 2698 sets of observation data on solar direct radiation in sub-divisions of wave band at 10 spots of seven regions in China, the empirical formula and nomograph for estimating ultraviolet irradiance at wa...According to 2698 sets of observation data on solar direct radiation in sub-divisions of wave band at 10 spots of seven regions in China, the empirical formula and nomograph for estimating ultraviolet irradiance at wavelength λ< 400nm were obtained. Furthermore, a climatological method for estimating diffuse ultraviolet irradiance under various sky conditions was also developed based on radiation transmission equations. Using monthly mean daa at fixed time from eight stations, monthly mean daily totals of direct, diffuse and global ultraviolet radiations, as well as their fractions in the whole wave band were estimated respectively. Results show that the fraction of global ultraviolet radiation in the whole wave band is rather conservative, 5.5±0.4 Percent under clear sky condition, and 5.3±0.4 Percent under mean sky condition.展开更多
To investigate the effect of reduced salinity on diatoms’ capacity to cope with changing ultraviolet radiation(U VR) and photosynthetically active radiation(PAR),Skeletonema costatum was grown in a range of salinity(...To investigate the effect of reduced salinity on diatoms’ capacity to cope with changing ultraviolet radiation(U VR) and photosynthetically active radiation(PAR),Skeletonema costatum was grown in a range of salinity(15,25,and 35).The photo system Ⅱ(PSⅡ) function was analyzed by increasing PAR and UVR to mimic a mixing event in turbulent waters.The re sults show that high UVR exposure significantly reduced PSII activity,especially in cells grown at low salinity.UVR,but not salinity,stimulated the ’removal’ rate of PSII protein PsbA.Salinity alone,in the range of 15 to 35,did not regulate PSⅡ acceptor region;however,the low salinity+UVR treatment decreased the energy flux for electron transport per PSⅡ reaction center in S.costatum.It showed that low salinity exacerbated the damaging effect of UVR on PSⅡ function in S.costatum by suppressing Psb A protein synthe sis and modifying the photochemistry of PSⅡ.Although higher catalase(CAT) activity and NPQs were induced,they were unable to prevent the combined damage effect of low salinity+UVR.Our findings indicate that reduced salinity and increased UVR potentially affect the abundance and distribution of S.costatum with the escalation of climate disturbances.展开更多
To further reveal the variation laws of ultraviolet radiation to provide better service for production and people's life, based on observation data of solar ultraviolet radiation obtained by Xilinhot National Climate...To further reveal the variation laws of ultraviolet radiation to provide better service for production and people's life, based on observation data of solar ultraviolet radiation obtained by Xilinhot National Climate Observatory in 2007-2012, the variation laws of solar ultraviolet radiation and its relationship with meteorological factors in different cloud conditions in Xilinhote were analyzed by using the mathematical and statistical methods and SPSS 11.5 software. The results showed that the solar ultraviolet radiation had obvious daily, seasonal and annual variations; the solar ultraviolet radiation was weak in the morning and evening but strong at noon; the maximum appeared from June to August, while the minimum appeared in November and December. It had significant correlation with total solar radiation, photosynthetically active radiation, air temperature, air humidity and ground temperature (0-5 cm). At present, the maximum intensity of ultraviolet radiation (UV-B) was 0.20-1.91 W/m2 from January to March and 0.13-1.43 W/m2 from October to De- cember respectively, which were lower than the safety standard for people and animals (2 W/mZ). However, the maximum might appear from April to September, ranging from 2.02 to 3.39 W/m2, which was easy to bring a threat and harm to people and animals.展开更多
A new remote sensing method is described to determine the vertical distribution and total content of atmospheric ozone. The method combines surface infrared, satellite infrared and ultraviolet channels. The width of t...A new remote sensing method is described to determine the vertical distribution and total content of atmospheric ozone. The method combines surface infrared, satellite infrared and ultraviolet channels. The width of the infrared channels is 0.01 cm-1, less than Lorentz half-width at the earth's surface, rather than the present width, because these channels can obtain information about variations in the ozone profile below the profile main-peak. The numerical experiments show that the method has a satisfactory precision in determining total ozone content, just about I percent error, and vertical distribution from the earth to 65 km space. In addition, some semi-analysis functions lor calculating backscattered ultraviolet and a relaxation equation are described in this paper.展开更多
Research on the effects of ultraviolet-B (UV-B) radiation on soybean seed quality is limited. The objective of this study was to quantify UV-B doses, 0, 5, 10 & 15 kJ•m<sup>–</sup>2•...Research on the effects of ultraviolet-B (UV-B) radiation on soybean seed quality is limited. The objective of this study was to quantify UV-B doses, 0, 5, 10 & 15 kJ•m<sup>–</sup>2•d<sup>–</sup>1, on soybean growth and seed quality. The experiment was conducted in the Soil-Plant-Atmosphere-Research (SPAR) facility. Chambers located at the R.R. Foil Plant Science Research Facility of Mississippi State University, Mississippi, USA, were used. Each SPAR chamber consists of a steel soil bin to accommodate the root system, a Plexiglas chamber to accommodate plant canopy and a heating, and cooling system connected to air ducts that pass conditioned air to cause leaf flutter through the plant canopy. The SPAR units, supported by an environmental monitoring and control systems, are networked to provide automatic acquisition and storage of the data, monitored every 10 seconds throughout the day and night. Soybean cultivar Pioneer 93Y92 (maturity group IV, Roundup Ready) was used in the study. The desired UV-B radiation was supplied by square-wave UV-B supplementation systems under near ambient PAR and delivered to plants for eight hours, each day, from 08:00 to 16:00 h by eight fluorescent UV-313 lamps. The results showed that increased UV-B did not influence many of the growth parameters because the treatments were imposed at mid-fruiting period. Seed quality parameters that are important for seed industry and human and animal nutrition were all affected by UV-B. Protein and palmitic and oleic acids declined linearly, while oil and linoleic and linolenic acid contents increased with increased UV-B. Sucrose, stachyose, and stearic acid contents showed quadratic trends, increased to about 4 - 5 kJ of UV-B and declined at higher doses. Thus, both current and projected UV-B radiation levels can modify soybean growth and seed quality. The functional algorithms developed in this study could be useful to develop UV-B- specific sub-models for soybean farm management and in policy decision areas.展开更多
The transmission of infectious diseases is influenced by several meteorological factors. In this study, the influence of several such factors in the transmission of COVID-19 (from 26 March 2020 to 29 July 2021) in the...The transmission of infectious diseases is influenced by several meteorological factors. In this study, the influence of several such factors in the transmission of COVID-19 (from 26 March 2020 to 29 July 2021) in the arid weather of Riyadh, Saudi Arabia was investigated using the Spearman and Kendall rank tests. The factors considered were the average, maximum, and minimum values of air temperatures, air pressure, wind speed, relative humidity, absolute humidity, dew point temperatures, and the average values of the global solar radiation and ultraviolet radiation at bands A and B. The data on meteorological factors were obtained from the King Abdulaziz City for Science and Technology (KACST) weather station, whereas the data on the daily COVID-19 cases were obtained from the official webpage of the Saudi Arabian Ministry of Health (MOH). The results revealed that air temperature (average, minimum, and maximum) average and maximum wind speed, maximum dew point temperature, global solar radiation, and ultraviolet radiation at A and B bands are positively associated with the daily number of COVID-19 cases reported in Riyadh. However, relative humidity, atmospheric pressure (averages, minimum, and maximum) is anti-correlated with the number of daily COVID-19 cases, while absolute humidity exerts no influence. These results are in total agreement with some of the previously established studies and are either contradicted partly or totally with others conducted at several locations around the world. The results could help not only epidemiologists understand the behavior of COVID-19 against meteorological variables but also national and international organizations and healthcare policymakers devise control strategies to combat the virus.展开更多
基金Research of the photoelectric properties of theκ(ε)-Ga_(2)O_(3)films was supported by the Russian Science Foundation,grant number 20-79-10043-P.Fabrication of the ultraviolet detectors based on theκ(ε)-Ga_(2)O_(3)layers was supported by the grant under the Decree of the Government of the Rus-sian Federation No.220 of 09 April 2010(Agreement No.075-15-2022-1132 of 01 July 2022)Research of the structural prop-erties of theκ(ε)-Ga_(2)O_(3)was supported by the St.Petersburg State University,grant number 94034685.
文摘High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in detail.Theκ(ε)-Ga_(2)O_(3)layers were deposited by the halide vapor phase epitaxy on patterned GaN templates with sapphire substrates.The spectral dependencies of the photoelectric properties of struc-tures were analyzed in the wavelength interval 200-370 nm.The maximum photo to dark current ratio,responsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 arb.un.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,respectively,at a wavelength of 200 nm and an applied voltage of 1 V.The enhancement of the photoresponse was caused by the decrease in the Schottky barrier at the Pt/κ(ε)-Ga_(2)O_(3)interface under ultraviolet exposure.The detectors demon-strated could functionalize in self-powered mode due to built-in electric field at the Pt/κ(ε)-Ga_(2)O_(3)interface.The responsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero applied voltage were 0.9 mA/W and 0.46%,respectively.The rise and decay times in self-powered mode did not exceed 100 ms.
基金supported by the National NaturalScience Foundation of China (30700085)the National Basic Re-search Program of China (2009CB421101)
文摘This review describes the effects of ultraviolet-B (UV-B) radiation on plant growth and development, photosynthesis and photosynthetic pigments and UV-B absorbing compounds. Moreover, plant ecosystem level responses to elevated UV-B radiation and interactions of UV-B radiation with abiotic and biotic factors were also involved. Results collected in this review suggest that approximately two-thirds terrestrial plant species are significantly affected by increase in UV-B radiation, The majority of evidences indicate that elevated UV-B radiation is usually detrimental but there exists tremendous variability in the sensitivity of species to UV-B radiation, and sensitivity also differs among cultivars of the same species.
基金Supported by National Natural Science Foundation of China(31270225)~~
文摘In order to investigate the protective effect of aloe anthraquinones on growth and development of soybean against ultraviolet B radiation stress from the morphological structure and physio-chemical indices. The results showed that, stressed by the enhanced ultraviolet b radiation, the soybean gave a dwarfed plant, shrunken leaf area and decreased photosynthetic pigment, while an ascended MDA content. Spraying aloe anthraquinones effectively relieved the reductions of chloro- phyll content and biomass and decreased the production of MDA under the radia- tion of UV-B. Moreover, under the UV-B radiation, waxy substances on epidermal cells increased remarkably and the stomas showed obvious subsidence, while spraying aloe anthraquinones could maintain the structure and shape of cells similar to that under natural light, and the stomas subsidence as well.
文摘A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors.
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Polytetrafluoroethylene (Teflon), a widely used spacecraft material, isstudied to investigate the vacuum ultraviolet (VUV) effects and its synergistic effects with atomicoxygen (AO) in a ground-based simulation facility. The samples before and after the experiments arecompared in appearance, mass, optical properties and surface composition. The reactioncharacteristics of Teflon are summarized and the reaction mechanisms are analyzed. The followingconclusion can be drawn: at the action of VUV the Teflon sample surface is darkened for theaccumulation of carbon; and when the sample is exposed to AO, the carbon is oxidized and thedarkening surface is bleached; the synergistic effects of VUV and AO may cause the erosion of Teflonmore severe.
文摘Seven hundred and twenty one-day-old AA broiler chickens were randomly allocated into two groups (male and female for half), and put into two identical closed houses with different lighting programs. The first house was illuminated by using common incandescence light, and the second one was added with ultraviolet radiation light from the second week onwards. The birds lived in a floor with litters and free access to feed and water. Temperature, humidity and immune programs in the two houses were similar. The results showed that under ultraviolet radiation, the growth speed of skeleton increased (the shank length was significantly increased in the third week, P〈0.05; the leg muscle weight was significantly improved by 3.87%, P〈 0.05); the skeleton quality improved (the density of skeleton mineralization was significantly increased by 6.11%, P 〈 0.01; serum calcium, phosphorus, and alkaline phosphatase activity were all improved); and the growth performance was improved (feed conversion ratio was improved by 1.4% averagely; the uniformity of body weight, the shank length, the inclined body length and body height were significantly improved) in broiler chicken.
基金supported by the National Natural Science Foundation of China(NSFC30700652,NSFC 30800895)which for the Doctoral Program of Higher Education of China(20070159022)the Liaoning Provincial Science and Technology Development Fund (20062087).
文摘Objective Solar ultraviolet (UV) radiation is an important environmental factor that affects human health. The understanding of diurnal variations of UV radiation at anatomical sites may be helpful in developing ways to protect humans from the harmful effects of UV radiation. Methods In order to characterize the diurnal variations, the UV exposure values were measured at 30 min intervals by using Solar-UV Sensors and a rotating manikin in Shenyang city of China (41°51'N, 123°27%). Measurement data for four representative days (in each of the four seasons respectively) were analyzed. Results The diurnal variations in solar UV radiation at the shoulder, the forehead and the chest were similar to those associated with a horizontal control measurement. However, the diurnal variations at the eye and the cheek exhibited bimodal distributions with two peaks in spring, summer and autumn, and a unimodal distribution in winter. The UV exposure peaks at the eye and the cheek were measured at solar elevation angles (SEA) of about 30° and 40°, respectively. Conclusion The protection of some anatomical sites such as the eye from high UV exposure should not be focused solely on the periods before and after noon, especially in the places and seasons with high SEA.
文摘Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ultraviolet A (UVA) and ultraviolet B (UVB) radiation. The chronic ultraviolet irradiated guinea pig model was established, and visible changes in the skin including wrinkling, sagging and erythema were observed. Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH px) in the dorsal skin were determined using biochemical methods. The results showed:(1)PCF (5 % and 20%) could greatly protect the dorsal skin of guinea pig against wrinkling, sagging and erythema induced by UV radiation in a concentration dependent manner.(2)PCF could reduce MDA formation in the dorsal skin caused by UV irradiation, while increasing the activities of SOD and GSH px.(3)The differences among the PCF groups and UV model group were significant ( P <0.05, P <0.01). These results indicated that topical application of PCF provided broad solar UV spectrum photoprotection; and that the antioxidant property of PCF might play a role in photoprotection.
基金This work is financially supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology(No HIT2006 32)
文摘Vacuum ultraviolet radiation of Upilex-S polyimide film 25 μm thick was performed using a gas jet type of vacuum ultraviolet simulator which gives unfixed wavelength from 5 nm to 200 nm.Nanoparticles redeposited on the films were observed and the nanoparticles formed on the surface consist mainly of carbon clusters.Changes in the composition and the chemical characteristics of film surface after radiation were identified by X-ray photoelectron spectroscopy(XPS).Relative O content in the radiated area was found to be higher,while N content was lower than in the pristine area.This indicates that Upilex-S polyimide film releases N atoms as volatile species.And the C1s,O1s envelopes were fitted using Multipak Spectrum software.The surface morphologies on iradiated area were examined by Atomic Force Microscope(AFM).Pieces of radiant products protrude from the eradiated surface,leading to considerable roughness for the iradiated area.And the surface transmittance of Upilex-S film after radiation reduces.
基金The work was supported by the National Natural Sci-ence Foundation of China(Nos.41706126,41876173 and 41606176).
文摘The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were studied in dinoflag-ellate Prorocentrum lima cultured outdoors for 16 days and indoors for 18 days.In the outdoor experiment,UVA radiation(320-400 nm)increased the growth rate of this dinoflagellate when solar light intensities were<12%;decreased growth rates were observed when intensities were>12%.Exposure to UVB radiation(280-320 nm)alleviated the negative effects of UVA.In the indoor ex-periment,UVA and low doses of UVB enhanced growth rates.Addition of low doses of UVB to UVA exposure resulted in higher contents of Chl a and photoprotective pigments compared with UVA exposure only.The results of both experiments showed that UVB is the primary signal of UVAC synthesis.High-dose UVB exposure accelerated growth rates when UVAC contents were maintained at high levels,suggesting that the latter plays a key role in UVR damage protection.Furthermore,the repair rate was en-hanced by UVB exposure after 16 days of culture.This study confirms the positive effects of UVA and UVB on the growth of P.lima,with the latter enhancing the photoprotective and recovery pathways of the species.
基金The Public Science and Technology Research Funds Projects for Ocean Research of China under contract No.201505003the National Basic Research Program(973 Program)of China under contract No.2015CB954002the National Natural Science Foundation of China under contract Nos 41476155,41322039,41271378 and 41206168
文摘Ultraviolet (UV) radiation has a significant influence on marine biological processes and primary productivity; however, the existing ocean color satellite sensors seldom contain UV bands. A look-up table of wavelength- integrated UV irradiance (280-400 nm) on the sea surface is established using the coupled ocean atmosphere radiative transfer (COART) model. On the basis of the look-up table, the distributions of the UV irradiance at middle and low latitudes are inversed by using the satellite-derived atmospheric products from the Aqua satellite, including aerosol optical thickness at 550 nm, ozone content, liquid water path, and the total precipitable water. The validation results show that the mean relative difference of the 10 d rolling averaged UV irradiance between the satellite retrieval and field observations is 8.20% at the time of satellite passing and 13.95% for the daily dose of UV. The monthly-averaged UV irradiance and daily dose of UV retrieved by satellite data show a good correlation with the in situ data, with mean relative differences of 6.87% and 8.43%, respectively. The sensitivity analysis of satellite inputs is conducted. The liquid water path representing the condition of cloud has the highest effect on the retrieval of the UV irradiance, while ozone and aerosol have relatively lesser effect. The influence of the total precipitable water is not significant. On the basis of the satellite-derived UV irradiance on the sea surface, a preliminary simple estimation of ultraviolet radiation's effects on the global marine primary productivity is presented, and the results reveal that ultraviolet radiation has a non-negligible effect on the estimation of the marine primary productivity.
基金supported by the National Natural Science Foundation of China (NSFC30700652)
文摘Objective This work explores the diurnal variation of Solar ultraviolet radiation (UVR) and total solar radiation (TSR) in northeast China,using daily observations of UVR and TSR in Shenyang.Methods UVR and TSR measurements were carried out from March 1st,2006 to December 31st,2009 in Shenyang,Liaoning province,China (41°51' N,123°27' E).Results Both TSR and UVR showed seasonal variation,reaching the highest levels in summer and the lowest in winter.They showed the greatest fluctuation in summer and autumn.The irradiance of TSR and UVR on clear days around the equinoxes and solstices increased substantially compared with the mean seasonal irradiance,especially in autumn.The whole day accumulated dose of UVR in winter was far less than that during the middle part of a summer day (i.e.between 10:00 and 14:00).It was also less than the accumulated summer dose of morning and afternoon (i.e.between 8:00 and 10:00 and 14:00 and 16:00).Conclusion The instant irradiance and daily accumulated amount of UVR are low in Shenyang,especially in autumn and winter.Thus concern about the health effects arising because shortage of UVR in northeast China is warranted.
文摘Polysiloxane/SiO2 hybrid coatings have been prepared on Kapton films by a sol-gel process. The erosion resistance of polysiloxane/Si02 (20 wt pct) coating was evaluated by exposure tests of vacuum ultraviolet radiation (VUV) and atomic oxygen beam (AO) in a ground-based simulation facility. The experimental results indicate that this coating exhibits better AO resistance than pure polysiloxane coating. The erosion yield (Ey) of the polysiloxane/Si02 (20 wt pct) hybrid coating is about 10-27 cm3/atom, being one or two orders of magnitude lower than that of polysiloxane. VUV radiation can affect the erosion process greatly. Under simultaneous AO and VUV exposure, the value of Ey of the polysiloxane/5iO2 (20 wt pct) hybrid coating increases by 3g% compared with that under single AO exposure.
文摘According to 2698 sets of observation data on solar direct radiation in sub-divisions of wave band at 10 spots of seven regions in China, the empirical formula and nomograph for estimating ultraviolet irradiance at wavelength λ< 400nm were obtained. Furthermore, a climatological method for estimating diffuse ultraviolet irradiance under various sky conditions was also developed based on radiation transmission equations. Using monthly mean daa at fixed time from eight stations, monthly mean daily totals of direct, diffuse and global ultraviolet radiations, as well as their fractions in the whole wave band were estimated respectively. Results show that the fraction of global ultraviolet radiation in the whole wave band is rather conservative, 5.5±0.4 Percent under clear sky condition, and 5.3±0.4 Percent under mean sky condition.
基金Supported by the Shandong Provincial Natural Science Foundation(Nos.ZR2019MC015,ZR2020QC025,ZR2020MD092)the open project of Rongcheng Marine Industrial Technology Research Institute,Ludong University(No.KF20180001)the Key Technology Research and Development Program of Shandong(No.2019GSF107091)。
文摘To investigate the effect of reduced salinity on diatoms’ capacity to cope with changing ultraviolet radiation(U VR) and photosynthetically active radiation(PAR),Skeletonema costatum was grown in a range of salinity(15,25,and 35).The photo system Ⅱ(PSⅡ) function was analyzed by increasing PAR and UVR to mimic a mixing event in turbulent waters.The re sults show that high UVR exposure significantly reduced PSII activity,especially in cells grown at low salinity.UVR,but not salinity,stimulated the ’removal’ rate of PSII protein PsbA.Salinity alone,in the range of 15 to 35,did not regulate PSⅡ acceptor region;however,the low salinity+UVR treatment decreased the energy flux for electron transport per PSⅡ reaction center in S.costatum.It showed that low salinity exacerbated the damaging effect of UVR on PSⅡ function in S.costatum by suppressing Psb A protein synthe sis and modifying the photochemistry of PSⅡ.Although higher catalase(CAT) activity and NPQs were induced,they were unable to prevent the combined damage effect of low salinity+UVR.Our findings indicate that reduced salinity and increased UVR potentially affect the abundance and distribution of S.costatum with the escalation of climate disturbances.
基金Supported by Scientific Research Project of Public Welfare Industry(Meteorology)(GYHY201506001-2)~~
文摘To further reveal the variation laws of ultraviolet radiation to provide better service for production and people's life, based on observation data of solar ultraviolet radiation obtained by Xilinhot National Climate Observatory in 2007-2012, the variation laws of solar ultraviolet radiation and its relationship with meteorological factors in different cloud conditions in Xilinhote were analyzed by using the mathematical and statistical methods and SPSS 11.5 software. The results showed that the solar ultraviolet radiation had obvious daily, seasonal and annual variations; the solar ultraviolet radiation was weak in the morning and evening but strong at noon; the maximum appeared from June to August, while the minimum appeared in November and December. It had significant correlation with total solar radiation, photosynthetically active radiation, air temperature, air humidity and ground temperature (0-5 cm). At present, the maximum intensity of ultraviolet radiation (UV-B) was 0.20-1.91 W/m2 from January to March and 0.13-1.43 W/m2 from October to De- cember respectively, which were lower than the safety standard for people and animals (2 W/mZ). However, the maximum might appear from April to September, ranging from 2.02 to 3.39 W/m2, which was easy to bring a threat and harm to people and animals.
文摘A new remote sensing method is described to determine the vertical distribution and total content of atmospheric ozone. The method combines surface infrared, satellite infrared and ultraviolet channels. The width of the infrared channels is 0.01 cm-1, less than Lorentz half-width at the earth's surface, rather than the present width, because these channels can obtain information about variations in the ozone profile below the profile main-peak. The numerical experiments show that the method has a satisfactory precision in determining total ozone content, just about I percent error, and vertical distribution from the earth to 65 km space. In addition, some semi-analysis functions lor calculating backscattered ultraviolet and a relaxation equation are described in this paper.
文摘Research on the effects of ultraviolet-B (UV-B) radiation on soybean seed quality is limited. The objective of this study was to quantify UV-B doses, 0, 5, 10 & 15 kJ•m<sup>–</sup>2•d<sup>–</sup>1, on soybean growth and seed quality. The experiment was conducted in the Soil-Plant-Atmosphere-Research (SPAR) facility. Chambers located at the R.R. Foil Plant Science Research Facility of Mississippi State University, Mississippi, USA, were used. Each SPAR chamber consists of a steel soil bin to accommodate the root system, a Plexiglas chamber to accommodate plant canopy and a heating, and cooling system connected to air ducts that pass conditioned air to cause leaf flutter through the plant canopy. The SPAR units, supported by an environmental monitoring and control systems, are networked to provide automatic acquisition and storage of the data, monitored every 10 seconds throughout the day and night. Soybean cultivar Pioneer 93Y92 (maturity group IV, Roundup Ready) was used in the study. The desired UV-B radiation was supplied by square-wave UV-B supplementation systems under near ambient PAR and delivered to plants for eight hours, each day, from 08:00 to 16:00 h by eight fluorescent UV-313 lamps. The results showed that increased UV-B did not influence many of the growth parameters because the treatments were imposed at mid-fruiting period. Seed quality parameters that are important for seed industry and human and animal nutrition were all affected by UV-B. Protein and palmitic and oleic acids declined linearly, while oil and linoleic and linolenic acid contents increased with increased UV-B. Sucrose, stachyose, and stearic acid contents showed quadratic trends, increased to about 4 - 5 kJ of UV-B and declined at higher doses. Thus, both current and projected UV-B radiation levels can modify soybean growth and seed quality. The functional algorithms developed in this study could be useful to develop UV-B- specific sub-models for soybean farm management and in policy decision areas.
文摘The transmission of infectious diseases is influenced by several meteorological factors. In this study, the influence of several such factors in the transmission of COVID-19 (from 26 March 2020 to 29 July 2021) in the arid weather of Riyadh, Saudi Arabia was investigated using the Spearman and Kendall rank tests. The factors considered were the average, maximum, and minimum values of air temperatures, air pressure, wind speed, relative humidity, absolute humidity, dew point temperatures, and the average values of the global solar radiation and ultraviolet radiation at bands A and B. The data on meteorological factors were obtained from the King Abdulaziz City for Science and Technology (KACST) weather station, whereas the data on the daily COVID-19 cases were obtained from the official webpage of the Saudi Arabian Ministry of Health (MOH). The results revealed that air temperature (average, minimum, and maximum) average and maximum wind speed, maximum dew point temperature, global solar radiation, and ultraviolet radiation at A and B bands are positively associated with the daily number of COVID-19 cases reported in Riyadh. However, relative humidity, atmospheric pressure (averages, minimum, and maximum) is anti-correlated with the number of daily COVID-19 cases, while absolute humidity exerts no influence. These results are in total agreement with some of the previously established studies and are either contradicted partly or totally with others conducted at several locations around the world. The results could help not only epidemiologists understand the behavior of COVID-19 against meteorological variables but also national and international organizations and healthcare policymakers devise control strategies to combat the virus.