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uv radiation INDUCED GRAFT COPOLYMERIZATION OF ALLYL ACETATE ONTO POLY(ETHYLENE TEREPHTHALATE)(PET) FILMS FOR FUEL CELL MEMBRANES

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Chinese Journal of Polymer Science 2012年第2期30卷 227-234页

作者： Mostak Ahmed Mubarak A.Khan Nazia Rahman M.Anwar H.Khan radiation and Polymer Chemistry Laboratory Institute of Nuclear Science and TechnologyBangladesh Atomic Energy CommissionP.O.Box 3787DhakaBangladesh Department of Chemistry Shahjalal University of Science and TechnologySylhet-3114Bangladesh Department of Geography University of California BerkeleyBerkeleyCA 94720USA

Ultraviolet （uv）-induced graft copolymerization of allyl acetate （AA） monomer onto poly（ethylene terephthalate）（PET） films and the subsequent sulfonation on the monomer units in the grafting chain using chlorosulfonic acid （C1SO3H） were carried out to prepare proton exchange membranes （PEMs） for fuel cells. A maximum grafting value of 12.8% was found for 35 vol% allyl acetate after 3 h radiation time. Optimum concentration of C1SO3H was selected for the sulfonation reaction to be 0.05 mol/L based on the degree of sulfonation and the tensile strength studies of the membrane. The degree of sulfonation increased as the sulfonation reaction temperature and sulfonation time were increasing. The radiation grafting and the sulfonation have been confirmed by titrimetric and gravimetric analyses as well as FTIR spectroscopy. The maximum ion exchange capacity （IEC） of 0.04125 mmol g-1 was found at 12.1% degree of sulfonation and the maximum proton conductivity was found to be 0.035 S cm-1 at 30℃ and a relative humidity of 60%. The various physical and chemical properties of the PEMs such as water uptake, mechanical strength, thermal durability and oxidative stability were also studied. To investigate the suitability of the prepared membrane for fuel cell applications, its properties were compared with those ofNafion 117.

关键词： Polymer electrolyte membrane Allyl acetate Fuel cell uv radiation Grafting Sulfonation.

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Enhanced electrochemical oxidation of phenol by introducing ferric ions and uv radiation

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Journal of Environmental Sciences 2008年第11期20卷 1386-1391页

作者： MAO, Xuhui WEI, Lin HONG, Song ZHU, Hua LIN, An GAN, Fuxing School of Resource and Environmental Science Environmental Engineering Department Wuhan University Wuhan 430079 China

The mineralization of phenol in aerated electrochemical oxidation has been *** results show that a cathodic Fenton process can occur when the Ti-0.3Mo-0.8Ni alloy material is used as cathode in solution containing ferric or ferrous ions; moreover,the reinforcement of cathodic Fenton process on the total organic carbon (TOC) removal rate of phenol is quite *** the metallic ions investigated,the ferric ion is the best catalyst for the electrochemical mineralization of phenol at initial...

关键词： mineralization phenol electrochemical oxidation cathodic Fenton process uv radiation

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The adsorption behavior of metals in aqueous solution by microplastics effected by uv radiation

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Journal of Environmental Sciences 2020年第1期32卷 272-280页

作者： Qiongjie Wang Yong Zhang Xiaoxue Wangjin Yulai Wang Guanhua Meng Yihua Chen School of Energy and Environment Anhui University of Technology

Microplastics are considered as the carrier to heavy metals in the *** the sorption ability of microplastics influenced by photo-aging is remaining *** the present study,the sorption of two kinds of metal ions(Cu^2+ and Zn^2+)in the aqueous solution by both the virgin and aged microplastics was *** terephthalate(PET)debris,one of the typical kinds of microplastics was chosen in this ***-aging of microplastics in environment was simulated using uv radiation in the *** analysis indicated that the aged microplastics had higher adsorption capacity of heavy metals than original *** could be related to the increased surface area and oxygen containing function appeared in the surface of aged microplastics after uv *** prolonging the time of radiation,the enhanced adsorption capacities of microplastics appeared for Cu^2+ and Zn^2+.These results showed a great interaction between the aging degree of plastics and sorption capacity to heavy ***,external conditions including temperature and pH value were also showed great influence to the adsorption behavior.

关键词： uv radiation Microplastics Adsorption Metal ions

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Light history modulates growth and photosynthetic responses of a diatom to ocean acidification and uv radiation

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Marine Life Science & Technology 2023年第1期5卷 116-125页

作者： Wei Li Tifeng Wang Douglas A.Campbell Kunshan Gao State Key Laboratory of Marine Environmental Science&College of Ocean and Earth Science Xiamen UniversityXiamen361005China College of Life and Environmental Sciences Huangshan UniversityHuangshan245041China Co-innovation Center of Jiangsu Marine Bio-industry Technology Jiangsu Ocean UniversityLianyungang222005China Biology Department Mount Allison UniversitySackvilleNBE4L 1G7Canada

To examine the synergetic effects of ocean acidification(OA)and light intensity on the photosynthetic performance of marine diatoms,the marine centric diatom Thalassiosira weissflogii was cultured under ambient low CO_(2)(LC,390μatm)and elevated high CO_(2)(HC,1000μatm)levels under low-light(LL,60μmol m^(-2)s^(-1))or high-light(HL,220μmol m^(-2)s^(-1))conditions for over 20 *** stimulated the growth rate by 128 and 99%but decreased cell size by 9 and 7%under LC and HC conditions,***,HC did not change the growth rate under LL but decreased it by 9%under *** combined with HC decreased both maximum quantum yield(FV/FM)and effective quantum yield(ΦPSII),measured under either low or high actinic *** exposed to uv radiation(uvR),LL-grown cells were more prone to uvA exposure,with higher uvA and uvR inducing inhibition ofΦPSII compared with HL-grown *** use efficiency(α)and maximum relative electron transport rate(rETRmax)were inhibited more in the HC-grown cells when uvR(uvA and uvB)was present,particularly under *** results indicate that the growth light history influences the cell growth and photosynthetic responses to OA and uvR.

关键词： Chlorophyll fluorescence Growth Light intensity Ocean acidification Pigmentations uv radiation

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VAMP726 from maize and Arabidopsis confers pollen resistance to heat and uv radiation by influencing lignin content of sporopollenin

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Plant Communications 2023年第6期4卷 163-178页

作者： Wenqi Yang Dongdong Yao Haiyang Duan Junli Zhang Yaling Cai Chen Lan Bing Zhao Yong Mei Yan Zheng Erbing Yang Xiaoduo Lu Xuehai Zhang Jihua Tang Ke Yu Xuebin Zhang State Key Laboratory of Crop Stress Adaptation and Improvement Henan Joint International Laboratory for Crop Multi-Omics ResearchSchool of Life SciencesHenan UniversityKaifeng 475004China National Key Laboratory of Wheat and Maize Crop Science College of AgronomyHenan Agricultural UniversityZhengzhou 450002China The Shennong Laboratory Zhengzhou 450002China College of Chemistry Zhengzhou UniversityZhengzhou 450001China National Engineering Laboratory of Crop Stress Resistance School of Life ScienceAnhui Agricultural UniversityHefei 230036China

Sporopollenin in the pollen cell wall protects male gametophytes from *** derivatives,including guaiacyl(G)lignin units,are known to be structural components of sporopollenin,but the exact composition of sporopollenin remains to be fully *** analyzed the phenylpropanoid derivatives in sporopollenin from maize and Arabidopsis by thioacidolysis coupled with nuclear magnetic resonance(NMR)and gas chromatography–mass spectrometry(GC–MS).The NMR and GC–MS results confirmed the presence of p-hydroxyphenyl(H),G,and syringyl(S)lignin units in sporopollenin from maize and ***,H units account for the majority of lignin monomers in sporopollenin from these *** next performed a genome-wide association study to explore the genetic basis of maize sporopollenin composition and identified a vesicle-associated membrane protein(ZmVAMP726)that is strongly associated with lignin monomer composition of maize *** manipulation of VAMP726 affected not only lignin monomer composition in sporopollenin but also pollen resistance to heat and uv radiation in maize and Arabidopsis,indicating that VAMP726 is functionally conserved in monocot and dicot *** work provides new insight into the lignin monomers that serve as structural components of sporopollenin and characterizes VAMP726,which affects sporopollenin composition and stress resistance in pollen.

关键词： pollen cell wall sporopollenin lignin monomers heat stress uv radiation

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Oxidative Degradation of Thermoplastic Starch Induced by uv radiation

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Journal of Renewable Materials 2019年第4期7卷 383-391页

作者： Mayte M.Quispe Olivia V.López Marcelo A.Villar Planta Piloto de Ingeniería Química PLAPIQUI(UNS CONICET)Bahía Blanca(8000)Argentina Departamento de Ingeniería Química Universidad Nacional del Sur(UNS)Bahía Blanca(8000)Argentina

Among biopolymers,thermoplastic starch(TPS)is a good candidate to obtain biomaterials because of its natural origin,biodegradable character,and *** to ultraviolet(uv)radiation causes significant degradation of starch-based materials,inducing photooxidative reactions which result in breaking of polymer chains,production of free radical,and reduction of molar *** changes produce a deterioration of TPS mechanical properties,leading to useless materials after an unpredictable *** this work,changes induced on TPS by uv radiation,analyzing structural properties and mechanical behavior,are *** was obtained through thermo-mechanical processing of native corn starch in the presence of water(45%w/w)and glycerol(30%w/w)as *** were obtained by thermocompression and,before testing,specimens were conditioned to reduce material *** process was performed by exposing TPS to 264 h uv radiation in a weathering test ***’s weight loss was determined *** changes were studied by Fourier Transform Infrared Spectroscopy(FTIR)and morphological modifications were analyzed by Scanning Electron Microscopy(SEM).Reduction of weight average molar mass was measured by Static Light Scattering(SLS).Changes in mechanical properties were studied from tensile *** 96 h exposure,TPS specimens presented a weight reduction of 4-6%,mainly attributed to plasticizers lost by *** observations showed that uv radiation induced morphological changes on TPS,evidenced by an increment of specimens *** FTIR,it was detected the presence of an additional band located at 1726 cm-1 in samples submitted to uv radiation,attributed to the formation of-C=O *** average molar mass of native starch was in the order of 107 g *** exposure to uv radiation decreased significantly its molar mass,confirming molecular degradation of the *** TPS was exposed during 48 h,it

关键词： Thermoplastic starch uv radiation structural properties mechanical behavior

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

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Journal of Arid Land 2018年第3期10卷 416-428页

作者： MAO Bing ZHAO Lei ZHAO Qiong ZENG Dehui CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology Chinese Academy of Sciences College of Horticulture Jilin Agricultural University Daqinggou Ecological Station Institute of Applied Ecology Chinese Academy of Sciences

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 tre

关键词： lignin litter decomposition litter layer thickness nitrogen forest plantation photodegradation uv radiation

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Electron migration behavior of Au/Cu multilayer films on Si substrate under uv radiation

Electron migration behavior of Au/Cu multilayer films on Si ...

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中国真空学会2014学术年会

作者： Kai Yan Wenqing Yao Jiangli Cao Yunshuang Li Yanxue Wu Department of Chemistry Tsinghua University Institute for Advanced Materials and Technology University of Science and Technology Beijing

Au/Cu system is widely used in the semiconductor industries and many other fields(includingmicro-electromechanical systems,MEMS).As an electronic component,it is applied in the spacecrafts and works in the low earth orbit(LEO)environment,so it is invariably influenced by uv *** energy of uv photoelectron is strong enough to destroy the chemical structure in multilayer films of *** now there are no reports about chemical structure analysis of surface and interface of multilayer metal films under uv radiation and scientific judgment for their failure *** it is of essential importanceto improve or develope the new multilayer thin films to establish a suitable estimation method to perform early diagnose of the changes on interface structure in electrode *** experimental results indicated that the electron migration induced by uv radiation in vacuum was the main reason resulting in the directed diffusion of Cu atoms to surface layer from the Au/Cu interface,the damage of the originally designed interface chemical structure and the final failure of the *** the same time,the thermal effect induced the morphology change of the films surface,that provided the passage for Cu atoms diffusion to surface layer through crystal boundary of Au *** the steady stage under uv radiation,the concentration gradients dCCu/dz of Cu atoms linear decreased with the treatment time t.

关键词： Interface width uv radiation Electro migration Work function Interface diffusion

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Solar PAR and uv radiation affects the physiology and morphology of the cyanobacterium Anabaena *** 7120

Solar PAR and UV radiation affects the physiology and morpho...

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中国海洋湖沼学会藻类学分会第七届会员大会暨第十四次学术讨论会

作者： Murray T Brown School of Biological Sciences University of PlymouthDrake CircusPL4 8AA PlymouthUnited Kingdom

The impacts of solar PAR and uv radiation(uvR)on the growth,photosynthetic performance and morphology of the cyanobacterium Anabaena ***7120 were investigated under three different solar radiation treatments:exposures to a)constant low PAR(photosynthetic active radiation,400-700 nm),b)natural levels of solar radiation with and c)without uv radiation(290 -400nm).The photochemical efficiency was reduced by about 40% and 90% at day one when the cells were exposed to solar PAR or PAR+uvR,respectively,and recovered at a faster pace under the treatment without uvR in the following *** uvR inhibited the growth up to 40%,reduced trichome length by up to 49% and depressed the differentiation of heterocyst. Negligible concentrations of uv-absorbing compounds were found even in the presence of uvR. During the first 2 d of exposure to natural levels of PAR,carotenoid concentrations increased but no prolonged increase was *** formation was enhanced under elevated PAR levels with stimulated quantum yield and growth after an initial *** concentrations of carotenoids and a two-fold increase in the carotenoid to chlorophyll a ratio provided protection from the high levels of solar *** radiation treatments with uvR the relatively greater decrease in chlorophyll a concentrations compared with the increase in carotenoids was responsible for the higher carotenoid:chlorophyll a *** formation was-disrupted in the presence of solar ***,the longer term impact of heterocyst disruption to the survival of Anabaena *** further study.

关键词： Anabaena cyanobacteria growth heteroeyst differentiation PAR photosynthesis pigments uv-absorbing compounds uv radiation

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Saponin synthesis and cotton growth is antagonistically regulated by solar uv-B radiation

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Journal of Cotton Research 2018年第3期1卷 30-40页

作者： DEHARIYA Priti KATARIA Sunita GURUPRASAD Kadur Narayan PANDEY Govind Prakash School of Life Sciences Devi Ahilya University School of Biochemistry Devi Ahilya University Shri Vaishnav Vidyapeeth Vishwavidyalaya

Background: Earlier we have reported that the exclusion of solar uv-B increased the growth and yield of cotton plants as compared with ambient uv-B. The uv-B radiation effects on the saponins and the impact of ambient and reduced uv-B on the accumulation of saponins has not been investigated yet. Thus a field experiment was conducted to study the influence of solar uv-B on the growth response and saponin synthesis in cotton(Gossypium hirsutum) var. Vikram plants by the exclusion of uv-B. The cotton plants were grown in specially designed iron chambers, wrapped with filters that excluded uv-B(uv-B enhanced the growth of cotton plants in terms of plant height and leaf *** plant height in uv-B excluded plants was due to elongated internode and more number of *** in growth was accompanied by a decrease in the accumulation of saponins, which was quantified by the spectrophotometric, TLC and HPLC methods. Solvent extraction of saponins from the internodes and leaves were used for the bioassay of Amaranthus hypocotyl growth and expansion of cucumber cotyledons. Extracts obtained from the uv-B excluded plants(leaves and internodes) promoted the growth to a larger extent as compared with the extracts obtained from ambient grown ***: The result indicates that solar uv-B may possibly suppress the plant growth by regulating the synthesis of natural growth inhibitor’s like saponin.

关键词： Bioassay Cotton Growth Inhibitor Saponin uv radiation

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