学科分类
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6 个结果
  • 简介:Manybiologicalmaterials,suchaswoodandbone,possesshelicoidmicrostructuresatmicroscale,whichcanserveasreinforcingelementstotransferstressbetweencracksurfacesandimprovethefracturetoughnessoftheircomposites.Failureprocesses,suchasfiber/matrixinterfacedebondingandslidingassociatedwithpull-outofhelicalfibers,areresponsiblemainlyforthehighenergydissipationneededforthefracturetoughnessenhancement.Herewepresentsystemicanalysesofthepull-outbehaviorofahelicalfiberfromanelasticmatrixviathefiniteelementmethod(FEM)simulation,withimplicationsregardingtheunderlyingtougheningmechanismofhelicoidmicrostructures.Wefindthat,throughtheiruniformcurvatureandtorsion,helicalfiberscanprovidehighpull-outforceandlargeinterfaceareas,resultinginhighenergydissipationthataccounts,toalargeextent,forthehightoughnessofbiologicalmaterials.Thehelicityoffibershapeintermsofthehelicalanglehassignificanteffectsontheforce-displacementrelationshipsaswellasthecorrespondingenergydissipationduringfiberpull-out.

  • 标签: 螺旋结构 纤维拉出 生物材料 断裂韧性 纤维/基体 微观尺度
  • 简介:Wereportonanoveldibenzothiophene-basedtwo-photonfluorescentprobeforselectivenuclearbioimaging,whichcontainsbilaterallysymmetricalpyridineringsconnectedbyacentralconjugated-bridgedibenzothiophene.Thisprobepossessesalargetwo-photonabsorptioncross-sectionof471GM,yieldsa25-foldenhancementofthefluorescencetitration,andastrongerphotostabilityfornucleilabelingthanexistingprobes.Thereal-timeobservationperiodisaminimumof1800sunderafemtosecondlaserexcitation,whichissignificantlylongerthanthatof40,6-diamidino-2-phenylindole.Theaboveresultsconfirmthatthisnovelmoleculeisasuitabletwo-photonfluorescentprobeforapplicationtonuclearbioimagingincells.

  • 标签: 双光子吸收截面 荧光探针 生物成像 应用 细胞 二苯并噻吩
  • 简介:生物土壤外壳为在干旱、半干旱的desertification区域改进生态的环境用作一个前卫。它是本地生态的环境正在承担的改进的水平的好指示物。在荒芜的区域,水状况是改进生态的环境的一个关键因素。作为第一层保护,生物外壳由于他们保存并且维持潮湿的能力在本地植被继任起一个重要作用。把在Ningxia省的Yanchi荒芜的Maowusu用作一个例子,在三年研究以后,当研究反对,这篇论文包括在Artemisiaordosica的盖子下面的地衣,苔藓和cyanobacterial选择三种生物外壳。这研究的结果显示那,外壳越近生物到Artemisiaordosica植被,他们越thicker变得。在Artemisiaordosica植被的一样的位置,苔藓外壳的厚度最高,由cyanobacterial外壳的地衣外壳,和厚度列在后面最低。生物土壤外壳范围保护土壤层的自然的水内容免受0~5 的伤害;厘米。另外,它完成掉落的水到更深渗透,并且不能阻止表面水内容有效地蒸发。堵住水渗入的生物外壳的效果随降雨的增加减少。在一样的降雨水平,苔藓外壳提供最强壮的水渗入阻塞,由地衣外壳和cyanobacterial外壳列在后面。随降雨的增加,水渗入的深度增加。在一样的降雨水平,水渗入深度的关系如下:cyanobacterial外壳>地衣外壳>苔藓外壳。随生物外壳厚度的增加,他们堵住水渗入能力更强壮,并且水渗入的深度更小。生物外壳上的模仿的降雨过程的特征上的分析证明沙的土地能被使用适当人工的生物外壳造一个持续森林保护系统并且在desertification区域创造一个稳定的生态系统修理。

  • 标签: 生物土壤结皮 水分入渗 毛乌素沙漠 水蒸发 宁夏 生物结皮
  • 简介:AseriesofnovelN-(3-furan-2-yl-1-phenyl-1H-pyrazol-5-yl)amidesderivativesweredesignedandsynthesized.Theirstructureswereconfirmedby1HNMR,13CNMRandHRMS.Alltitlecompoundswereevaluatedfortheirherbicidalandantifungalactivities.Preliminarybioassayresultsindicatedthatthetitlecompoundsshowedgoodtomoderateherbicidalactivityat1000mg/L.Compound6qpresentedthebestactivityagainstDigitariasanguinalis(L)Scop.,AmaranthusretroflexusL.andArabidopsisthalianawithaninhibitiondegreeoffive.Compound6dalsoshowedaninhibitiondegreeoffiveagainstD.sanguinalis.Inaddition,at50mg/L,mostcompoundsexhibitedgoodinvitroantifungalactivityagainstSclerotiniasclerotiorum,withcompound6cshowingover90%antifungalactivityagainstS.sclerotiorumandPelliculariasasakii.

  • 标签: 酰胺衍生物 生物活性 设计合成 除草活性化合物 抗真菌活性 油菜菌核病
  • 简介:Inthepresentstudy,aseriesofnovelnitricoxide-hydrogensulfidereleasingderivativesof(S)-3-n-butylphthalide((S)-NBP)weredesigned,synthesized,andevaluatedaspotentialantiplateletagents.CompoundNOSH-NBP-5displayedthestrongestactivityininhibitingthearachidonicacid(AA)-andadenosinediphosphate(ADP)-inducedplateletaggregationinvitro,with3.8-and7.0-foldmoreeffectivenessthan(S)-NBP,respectively.Furthermore,NOSH-NBP-5couldreleasemoderatelevelsofNOandH2S,whichwouldbebeneficialinimprovingcardiovascularandcerebralcirculation.Moreover,NOSH-NBP-5couldrelease(S)-NBPwhenincubatedwithratbrainhomogenate.Inconclusion,thesefindingsmayprovidenewinsightsintothedevelopmentofnovelantiplateletagentsforthetreatmentofthrombosis-relatedischemicstroke.

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