High-speed performance self-powered short wave ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)

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.

Effect of combination of ultraviolet radiation and biocide on fungal-induced corrosion of high-strength 7075 aluminum alloy

The effect of ultraviolet(UV)radiation and biocide benzalkonium chloride(BKC)on fungal-induced corrosion of AA7075 induced by Aspergillus terreus(A.terreus)was deeply studied using analysis of biological activity,surface analysis,and electrochemical measurements.Results demonstrated that the planktonic and sessile spore concentrations decline by more than two orders of magnitude when UV radiation and BKC are combinedly used compared with the control.UV radiation can inhibit the biological activity of A.terreus and influence the stability of passive film of AA7075.Except for direct disinfection,the physical adsorption of BKC on the specimen can effectively inhibit the attachment of A.terreus.The combination of UV radiation and BKC can much more effectively inhibit the corrosion of AA,especially pitting corrosion,due to their synergistic effect.The combined application of UV radiation and BKC can be a good method to effectively inhibit fungal-induced corrosion.

Increasing Surface UV Radiation in the Tropics and Northern Mid-Latitudes due to Ozone Depletion after 2010

Excessive exposure to ultraviolet(UV)radiation harms humans and ecosystems.The level of surface UV radiation had increased due to declines in stratospheric ozone in the late 1970s in response to emissions of chlorofluorocarbons.Following the implementation of the Montreal Protocol,the stratospheric loading of chlorine/bromine peaked in the late 1990s and then decreased;subsequently,stratospheric ozone and surface UV radiation would be expected to recover and decrease,respectively.Here,we show,based on multiple data sources,that the May–September surface UV radiation in the tropics and Northern Hemisphere mid-latitudes has undergone a statistically significant increasing trend[about 60.0 J m^(–2)(10 yr)^(–1)]at the 2σlevel for the period 2010–20,due to the onset of total column ozone(TCO)depletion[about−3.5 DU(10 yr)^(–1)].Further analysis shows that the declines in stratospheric ozone after 2010 could be related to an increase in stratospheric nitrogen oxides due to increasing emissions of the source gas nitrous oxide(N_(2)O).

Strain H_2-419-4 of Haematococcus pluvialis induced by ethyl methanesulphonate and ultraviolet radiation

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.

Effects of ultraviolet(UV) radiation and litter layer thickness on litter decomposition of two tree species in a semi-arid site of Northeast China

Forests and grasslands in arid and semi-arid regions receive high-intensity ultraviolet（UV） radiation year-round. However, how the UV radiation affects the litter decomposition on the forest floor remains unclear. Here, we conducted a field-based experiment in 2011 in the southeastern Horqin Sandy Land, Northeast China, to investigate the effects of UV radiation, litter layer thickness, and their interaction on the mass loss and chemical properties of decomposing litter from Xiaozhuan poplar（Populus × xiaozhuanica） and Mongolian pine（Pinus sylvestris var. mongolica） plantation trees. We found that UV radiation accelerated the decomposition rates of both the Xiaozhuan poplar litter and Mongolian pine litter. For both species, the thick-layered litter had a lower mass loss than the thin-layered litter. The interaction between UV radiation and litter layer thickness significantly affected the litter mass loss of both tree species. However, the effects of UV radiation on the chemical properties of decomposing litter differed between the two species, which may be attributed to the contrasting initial leaf litter chemical properties and morphology. UV radiation mostly had positive effects on the lignin concentration and lignin/N ratio of Xiaozhuan poplar litter, while it had negative effects on the N concentration of Mongolian pine litter. Moreover, litter layer thickness and its interaction with UV radiation showed mostly positive effects on the N concentration and lignin/N ratio of Xiaozhuan poplar litter and the ratios of C/N and lignin/N of Mongolian pine litter, and mostly negative effects on the C/N ratio of Xiaozhuan poplar litter and the N concentration of Mongolian pine litter. Together, these results reveal the important roles played by UV radiation and litter layer thickness in the process of litter decomposition in this semi-arid region, and highlight how changes in the litter layer thickness can exert strong influences on the photodegradation of litter in tree plantations.

Effects of Ultraviolet(UV)Radiation on Outdoor-and Indoor-Cultured Prorocentrum lima,a Toxic Benthic Dinoflagellate

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.

Research advances on the biological effects of elevated ultraviolet-B radiation on terrestrial plants

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.

The Effects of UV-B Radiation on Maize at the Seedling Stage

In this study, maize plant seedlings were grown in soilless cultures, with and without ^-B radiation at a close of 5.4 kJt（m2-d）. Three clays later, it was found that the treatment of UV-B radiation significantly reduced such characteristics as biomass, plant height, leaf area, and so on. Also, the photosynthesis of the maize was inhabited, the anti-oxid activity decreased, and the MDA concentration increased with the UV-B radiation exposure. The maize presented visible hybrid vigor under the control condition, while the hybrid vigor under UV-B radiation barely emerged in biomass, plant height, leaf area, and physiological metabolic index.

The Action of Aloe Anthraquinones in Protecting the Growth of Soybean from Ultraviolet Radiation Stress

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.

UV-LED表面消毒辐射场的数学模拟体系的建立及试验验证

为了实现紫外发光二极管(Ultraviolet Light-Emitting Diodes,UV-LED)表面消毒器设计的优化、高效、智能化目的,研究建立了UV-LED表面消毒辐射场的数学模型,并进行了试验验证。根据该数学模型,编写了VBA(Visual Basic for Applications)程序,对辐射场进行了模拟和分析。结果显示,辐射模型的计算值与实测值接近,试验验证了辐射模型的可行性。试验进行了应用举例,当照射距离与灯间距的比值为0.4时,选择最大发光角90°的UV-LED可使辐射场最优化;当照射距离与灯间距的比值为0.8和1.6时,对应的最优选择分别是45°和30°的UV-LED。数学模型和相关计算方法为优化设计紫外线表面消毒设施提供了模拟、优化的有效工具。

UV接枝聚硅氧烷-TiO_(2)复合棉织物的制备及性能

通过紫外辐射3-(异丁烯酰氧)丙基三甲氧基硅烷对棉织物进行接枝聚合改性,然后与钛酸四丁酯共水解,形成Si—O—Ti化学键,通过化学键合的形式引入TiO_(2)层。由于Si元素位于棉织物和二氧化钛之间,阻断TiO_(2)光催化降解棉织物。化学键合TiO_(2)与棉织物的结合强度高,提高了耐久性。TiO_(2)对棉织物的整体结构未造成改变,但棉织物的抗紫外线能力显著提升,禁带宽度变小,光催化自清洁能力增强。

红光补充UV-A对叶用莴苣倍半萜内酯类化合物的调控效应

叶用莴苣特有的苦味来源于倍半萜内酯类化合物,主要包括山莴苣苦素和莴苣苦素等。为探究紫外光对叶用莴苣生长和倍半萜内酯类化合物的调控作用,以纯红光(180μmol·m^(-2)·s^(-1))为对照,比较了补充UV-A(30μmol·m^(-2)·s^(-1))、UV-B(10μmol·m^(-2)·s^(-1))对7个叶用莴苣品种生长及倍半萜内酯类化合物的影响;并进一步分析了红外光添加UV-A补光强度(15、30、45μmol·m^(-2)·s^(-1))及补光时长(0、1、2、3、6、9 d)对叶用莴苣倍半萜内酯类化合物含量的影响。结果表明:添加UV-A处理可显著提高绿罗的地上部鲜质量,显著降低7个叶用莴苣品种的山莴苣苦素和莴苣苦素含量,分别降低了33%~74%和29%~60%。随着UV-A补光强度的增加,叶用莴苣中倍半萜内酯类化合物含量逐渐降低,且以添加30μmol·m^(-2)·s^(-1)UV-A处理2 d后叶用莴苣中山莴苣苦素含量迅速上升,处理3 d时达到峰值,随后逐渐降低;而莴苣苦素含量在处理2 d后基本保持逐步上升的趋势,处理6~9 d时略有下降。综上所述,红光补充适量的UV-A(30μmol·m^(-2)·s^(-1)、3~6 d),可在不影响生物量的基础上显著降低叶用莴苣中倍半萜内酯类化合物含量,从而减轻苦味。

Effects of Ultraviolet Radiation on Skeleton Development of Broiler Chickens

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.

Diurnal Variations in Solar Ultraviolet Radiation at Typical Anatomical Sites

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.

Experimental Study of Vacuum Ultraviolet Radiation Effects and Its Synergistic Effects with Atomic Oxygen on a Spacecraft Material-Polytetrafluoroethylene

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.

Effect of UV-B radiation on the feeding behavior of the rotifer Brachionus plicatilis

Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. , Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively （ P 〈 0.05 ） which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, L galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment （2.70 kJ/m^2）, the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, L galbana and T. chuii in turn. Chlorella sp. , L galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.

Surface investigation on Upilex-S polymide film iradiated by vacuum ultraviolet radiation

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.

Influences of the Clearness Index on UV Solar Radiation for Two Locations in the Tibetan Plateau——Lhasa and Haibei

Ultraviolet （UV） solar radiation has a significant influence on human health, the environment and climate. A series of measurements, including UV radiation （290 400 nm） and global solar radiation （Rs）, were continuously recorded from August 2004 at the Lhasa and Haibei sites on the Tibetan Plateau. Both observation sites＇ altitudes are above 3000 m and have similar meteorological conditions. The data from 2005 2006 was used to identify the varying characteristics of UV radiation. It＇s relation to the clearness index Ks, the relative optical mass mr, and Rs were established. The annual mean values of total daily UV radiation are 0.92 and 0.67 MJ m^-2 at Lhasa and Haibei, respectively. The UV radiation in Lhasa represented 4.6% of the global solar radiation while in Haibei this percentage was 4.2%. In the case of clear days （Ks 〉 0.8）, these percentages ranged between 4.0% and 4.5% in Lhasa and between 5.1% and 5.5% in Haibei. In the case of cloudy days （Ks 〈 0.4）, these percentages ranged from 4.4% to 6.8% in Lhasa and from 5.1% to 5.5% in Haibei. The maximum values of UV radiation for each relative optical mass diminished exponentially with mr. Thus, for Lhasa and Haibei, UV=46.25mr-129, and UV=51.76mr-142, respectively. The results of this study can be used to obtain more UV radiation data for the study of UV climate characteristics, the effects of UV on ecological processes and the feedback of the thinning of the stratospheric ozone, from more routine measurements Rs data.

Ground-based Observations of Ultraviolet and Total Solar Radiation in Shenyang,Northeast China

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.

Protective Effect of Topically Applied Polypeptide from Chlamys farreri Against Ultraviolet Radiation-Induced Chronic Skin Damage in Guinea Pig

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.