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简介：Theexfoliationdegreeofgraphiteoxideintographeneoxideplaysanimportantroleinthemassiveproductionmethodofreducedgrapheneoxide.Itissignificanttofindasimpleandfeasiblemethodtoanalyzetheexfoliationdegreeofgraphiteoxide.Inthepresentwork,graphiteoxidewassynthesizedbyamodifiedHummersmethod,andthengrapheneoxidecolloidswereobtainedbyexfoliationofgraphiteoxidedispersedinde-ionizedwater.UV-visiblespectroscopywasusedtocharacterizetheabsorptionofthegrapheneoxidecolloids,andtheconcentrationofgrapheneoxidecolloidsindicatedbyabsorptionareaofUV-visiblespectrawasstudied.Resultsshowthatthereisarelativelystablerelationshipbetweenthem,indicatingthatUVvisiblespectroscopyisapotentialmethodforanalyzingtheexfoliationdegreeofgraphiteoxideintographeneoxide.

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简介：何谓CrossUV跨界休旅车?相信国内消费者对SUV不陌生,SUV是“SportUtilityVehicle”的简称,即运动型多功能车.而CrossUV跨界休旅车,不仅拥有SUV的部分外形特征,还拥有轿车的低油耗以及更实用便利的空间等特点,兼顾时尚与旅行范儿,开创了跨界休旅车这一全新车型类别.

简介：ACe3+tion-dopedα-NaYF4singlecrystalofhighqualityisgrownsuccessfullybyanimprovedfluxBridgmanmethodundertheconditionsoftakingthechemicalrawcompositionofNaF:KF:YF3:CeF3inthemolarratioof30∶18∶48∶4,wheretheKFisshowntobeaneffectiveassistantflux.Thexraydiffraction,absorptionspectra,excitationspectra,andemissionspectraoftheCe3+t-dopedα-NaYF4singlecrystalaremeasuredtoinvestigatethephaseandopticalpropertiesofthesinglecrystals.TheabsorptionspectrumoftheCe3+t:α-NaYF4showsastrongbandthatpeaksatthewavelengthof300nm.TheemissionspectrumoftheCe3+t:α-NaYF4emitsanintenseultraviolet（UV）bandatthewavelengthof332nmundertheexcitationof300nmlight.Twoseparatedluminousbandsof330and350nm,whichcorrespondtothetransitions5d→2F25∕2and5d→F7∕2,canbeobtainedbyGaussfitting.ThestrongemissionintensityattheUVbandandtheexcellentopticaltransmissionintherangeofUVwavelengthsindicatethatCe3+t:α-NaYF4singlecrystalscanbeconsideredasapromisingmaterialforUVlasers.

简介：银电影(Ag)和有厚度~的silvergold电影(AgAu)15nm在通过热蒸发的Bk7眼镜上是涂的。在做5.2%的黄金以后，Ag电影的谷物尺寸从13.6把nm归结为9.1nm，也，表面粗糙从1.45nm减少到0.94nm。一盏紫外灯被用作照耀光来源在空气加速腐蚀过程。当AgAu电影更不降级时，在17h以后，照耀，纯银电影表面拐弯黑暗，和发射度从350把nm归结为500nm，几乎微不足道的在紫外放射以后。另外的X光光电子光谱学和原子力量显微图数据被提供显示出电影和他们的表面形态学的原子内容。小谷物尺寸和合金电影的高收拾行李密度在空气与氧阻止银的反应，这被建议，它导致AgAu电影的高稳定性。

简介：放射的转移模型模拟被用来调查erythemal紫外(EUV)由分开的修正因素紫外A并且UV-B光谱范围。修正因素被定义为改变扑灭的数量和特征并且散布材料引起的EUV的比率。EUV修正因素(CFEUV)为紫外A[CFEUV(A)]并且UV-B[CFEUV(B)]被变化在全部的臭氧，喷雾器和云的光深度，和太阳的天顶角度影响。CFEUV(A)和CFEUV(B)之间的差别也作为太阳的天顶角度，喷雾器和云的光深度，和全部的臭氧的功能被估计。CFEUV(A)和CFEUV(B)之间的差别为不同太阳的天顶角度和喷雾器和云的光深度在所有模拟为云为喷雾器从5.0%～25.0%，并且从9.5%～2.0%。CFEUV的衰落的率每统一光深度在之间紫外A并且UV-B为一样的喷雾器和云条件在多达20%不同。为全部的臭氧，因为，在CFEUV(A)的变化在CFEUV(B)与那相比是可以忽略的有效光谱臭氧吸收乐队的范围。另外，CFEUV的敏感由于在表面的变化调节(即，表面反照率和表面高度)被在这研究使用模型也估计。为在表面反照率的变化，CFEUV的敏感每0.1反照率变化是2.9%-4.1%，取决于喷雾器或云的数量。为在表面高度的变化，CFEUV(B)的敏感是两次CFEUV(A)的，因为光深度在更短的波长显著地增加了的瑞利。

简介：Theobjectiveofthisstudywastoinvestigatetheeffectofgelatin(SG)isolatedfromsalmonskinanditshydrolysate(SGH)onphotoagingskin,andthemechanismresponsibleforanti-photoaging.TheaveragemolecularweightsofSGandSGHwere65kDaand873Da,respectively.TheaminoacidcompositionsofSGandSGHweresimilar.Bothofthemwereabundantinhydrophobicaminoacids.Twenty-fivepeptideswereidentifiedfromSGH.SGandSGHcouldimproveUVirradiation-inducedpathologicalchangesofmacroscopicaltissuetextureandskinmorphology.Hydroxyprolinecontentisanindicatorofmatrixcollagencontent,SGandSGHcouldinhibitthedecreaseofhydroxyprolinecontentinphotoagingskininadosedependentmanner.Inaddition,SGandSGHcouldalleviateUVirradiation-inducedoxidativedamagestoskinbyincreasingtheactivitiesoftotalsuperoxidedismutase(T-SOD),glutathioneperoxidase(GSH-Px)andcatalase(CAT),increasingthecontentofglutathione(GSH)anddecreasingthecontentofmalonaldehyde(MDA).Moreover,SGandSGHcouldenhanceimmuneregulationsystembyincreasingthethymusindex.Thus,theanti-photoagingmechanismsofSGandSGHwerebyinhibitingthedepletionofantioxidantdefensecomponents,involvinginthesynthesisofcollagenandenhancingthefunctionofimmunesystem.Besides,SGHshowedabetterresultinprotectingskinfromphotoagingthanSG.

简介：菹草（Potamogetoncrispus）衰亡的原因一直是水体生态修复的研究热点。已有的研究认为,强光照是促进菹草衰亡的关键因素。分别将菹草幼苗置于150μW/cm2剂量的中波紫外线（UV-B,波长为275-320nm）辐射下,设置4种UV-B辐射持续时间处理,其每日的持续辐射时间分别设定为0h（对照处理）、2h、4h和6h,对照处理下的菹草幼苗不接受UV-B辐射,仅接受长波紫外线（UV-A）辐射和光合有效辐射,监测各处理下菹草幼苗的生长、形态状况、石芽形成和萌发等指标。研究结果表明,每日6h的UV-B辐射,能促进菹草分枝,且能促进菹草衰亡;2h和4h的UV-B辐射,对菹草的影响较小,随着UV-B辐射时间的延长,菹草植株的株高、节间距和单株鲜质量明显下降,每日2h的UV-B辐射,能促进植株叶面积的增加;每日延长UV-B辐射时间,可以促进石芽的形成,但形成的石芽随着变态率的增加,其长度增加、宽度减小,石芽质量减轻,下一个生长季的萌发率降低,萌发出二苗的比率降低,萌发苗的各项生长指标随着辐射剂量增加而逐渐降低。因此,在春末、夏初,随着太阳辐射时间的增加,阳光中累计的UV-B辐射剂量增加,这可能是促进菹草大批衰亡的重要原因。

简介：YPO_4phosphorssingle-dopedwithSb~（3＋）orGd~（3＋）andco-dopedwithSb~（3＋）andGd~（3＋）werepreparedbyasolid-statereactionmethod.Thephasepurity,morphology,photoluminescenceexcitationandemissionpropertiesofthepreparedphosphorswereinvestigated.TheresultsshowedthatSb~（3＋）couldsensitizeGd~（3＋）intheco-dopedphosphorswhichmadethephosphorsexcitablebyshort-waveultraviolet（UV）atawavelengthbetween220and260nm.Under253.7nmexcitation,theco-dopedphosphorsY_（1–x–y）PO_4：Sb~（3＋）x,Gd~（3＋）yshowedstrongemissionofGd~（3＋）atawavelengthof312nmwhoseintensitychangedwiththedopingconcentrationsofGd~（3＋）andSb~（3＋）.TheoptimizedY_（0.77）PO_4：Sb~（3＋）0.07,Gd~（3＋）0.16phosphorshowedanintensitycomparabletocommercialLaPO_4：Cephosphor（UVB-315）,makingitapotentialcandidateformercurylow-pressuredischargenarrow-bandUV-Bemittinglamps.

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简介：将苦豆子总碱和苦参碱制剂在不同的光和热条件下放置90d,用UV法和HPLC法对药物的光和热稳定性进行比较研究.方法：样品采用有机溶剂卒取,UV法测定药物含量,检测波长413nm,HPLC法采用SIGMADiscoveryC18柱（25cm×4.6mm,5μm）,以甲醇-0.05mol/L磷酸二氢钾（用磷酸氢二钾调PH至6.45）为流动相,波长220nm。比较药物浓度的RSD。结果：色谱图中峰分离良好。UV法的RSD值高于HPLC法,UV法产生的误差较大。结论：HPLC法比UV法测定方法重现性好,灵敏度好,精密度高。确定两种药物密封,4℃避光保存。