简介：在高中数学所涉及的各种基本运算中，倒数运算是很常见并且应用广泛的一种运算．理解并熟练掌握倒数运算，有助于我们解决许多数学问题．本文重点介绍了两种取倒数运算的方法，分别是公式口诀法和函数单调性法．

简介：读小学时我很调皮，有一天老师当众宣布了一条“禁令”：不准苏步青出校门!

简介：〔摘要〕化学平衡常数、电离平衡常数、沉淀溶解平衡常数位于选修四《化学反应原理》部分，属于新课标的新增内容。从近几年的高考中发现，化学平衡常数早已成为了高考命题的热点；电离平衡常数和沉淀溶解平衡常数也渐有“升温”的表现，因此，可以预测这“三大平衡常数”在今后的高考中，将继续成为今后高考的重点及热点。化学平衡常数的引入，对判断化学平衡移动方向带来了科学的依据。平衡常数是表征反应限度的一个确定的定量关系，是反应限度的最根本的表现。平衡常数的使用，从定量的角度解决了平衡的移动。所以学好化学平衡常数对于高中化学尤为重要。这部分内容的应用要求层次较高，难度较大，现作简要分析。

简介：本文从物理实验测量和计时仪器开发两个方面同时入手,从运动学角度出发,分别选用U形和条形遮光片,且灵活利用通用计数器的各个功能,综合提炼出7种实验方案测量阻尼常数,其测量值在1.31～1.53之间,实验结果重复性和一致性较好.同时开发新的计时仪器,直接应用于本实验,使测量过程变得简单易行.

简介：天线为通信系统中不可或缺的基本设备。随着电子产品轻、薄、短、小的趋势,电子产品中零件的设计也要朝此趋势发展。当前各界对于天线设计的重点在于小型化、结构简单化及多频或宽带。高介电常数基板可以缩小微波辐射波长,达到天线小型化的目的。文章采用酚醛树脂作为环氧树脂的固化剂,采用高介电常数填料作为功能填料。研制的高介电常数覆铜板具有低的热膨胀系数、低的介电损耗和低的吸水率,可以应用于微带天线。

简介：过载保护是电动机保护的重要组成部分，是保证电动机安全运行的前提条件。本文简单论述了异步电动机的发热和散热机理．针对电动机过载时转速降低致使散热效果变差这一现象进行了分析和研究，并在单时间常数电动机热过载保护模型的基础上提出了一种改进的保护模型及其相应算法，与传统单时间常数保护模型相对比，改进后的模型更接近电动机实际运行发热情况。可以作为电动机保护器的热过载模型使用。

简介：一、化学平衡常数的有关计算化学平衡常数的有关计算常考题型：A．平衡常数的求解；B．由平衡常数求算初始（或平衡）浓度；C．计算转化率（或产率）；D．应用K判断平衡移动方向（或放热、吸热等）。

简介：Polyphenylene（聚酰亚胺）树脂带有非常好的介电性能，通过对Polyphenylene分子细量化，然后和带有好架桥性能以及可溶混性的树脂搅拌，开发出了同时带有低诱电（Low-Dk）和高耐热性，适用于高速信号传输设备使用的多层线路板材料。这个材料性能为Dk=3．8，Df=0．005（1GHz），Tg=210℃。在5GHz的使用条件下，与传统的材料相比，降低信号损失约15db／m。可以广泛的应用在如网络设备等的高速，大容量信号传输设备。

简介：提出一种修正降雨特征衰减计算模型所需参数简单有效的分析方法,基于西安地区降雨物理特性测量结果和等效介电常数模型,利用文中的方法计算得到了20GHz～50GHz的参数,和ITU推荐的数据作了比较并进行了分析讨论,研究结果对精确评估降雨衰减特性有重要的理论意义和实用价值。

简介：海峡两岸都实行一纲多本的模式，而且每套教材都有自己的特色和侧重点。对台湾海峡两岸高中教材的“化学平衡常数”，从学段安排、教学内容、编写特点进行比较，获得启示。如大陆教材的知识体系编排的较好，而台湾教材的深广度大于大陆教材等等，在教学时取其之长，提高教学质量。

简介：应用权函数,给出一个有最佳常数因子的-3μ齐次半离散Hilbert型不等式.同时给出它的等价式.

简介：2009年伊朗国家选拔考试试题里，有这样一道不等式证明题：

简介：AIM:TodiscusstheimpactofLyciumBarbarumPolysaccharide(LBP)andDanshensupurifiedfromTraditionalChineseMedicine(TCM)onvascularendothelialgrowthfactor(VEGF)ofrabbitswithretinalneovascularization.METHODS:Fortyrabbitsweredividedintonormalcontrolgroup,modelcontrolgroup,LBPgroupandDanshensugroup.Animalsinthenormalcontrolgroupwerefedinthenormaloxygenenvironment.Animalsintheotherthreegroupswereputintotheenvironmentwith70%oxygenfor5daysinordertobuildthemodelofoxygen-inducedvascularproliferationretinopathy.AndthendifferentTCMextractwasinjectedintotheabdominalcavitiesoftheseannimals.After7days,theVEGFcontentofintheserumofrabbitwasmeasuredbydoubleantibodysandwichmethod.RESULTS:DataanalysisindicatedthatVEGFcontentwasasfollows:Danshensugroupwaslowerthanmodelcontrolgroup(12.92±3.84ng/Lvs19.32±4.15ng/L,P<0.05);LBPgroupandnormalcontrolgroupwerelowerthanmodelcontrolgroup(12.92±3.84ng/L,9.26±1.61ng/Lvs19.32±4.15ng/L,P<0.01);totalbloodviscosity,plasmaviscosity,cholesterolcontent,fibrinogencontentandtriacylglycerolcontentafterperitonealinjectionofLBPandDanshensuwereobviouslylowerthanbeforeinjection.CONCLUSION:TCMextract-LBPandDanshensucanprominentlyreducethecontentofVEGFintheprocessofvascularproliferativeretinopathyofrabbit;canpreventtheoccurrenceofretinalmicrovasculardiseasebyimprovingpartialoxygen-deficientenvironmentoraffectingallkindsofnewgrowthfactor.

简介：引子远处的廊柱模模糊糊的，目光无法聚焦在一点。脑袋像被搅拌机搅过一般，混混沌沌，四分五裂。渐渐地，男人注意到自己的手上拿着一样东西，那上面有红色的液体在延淌着。“血……”他的脑中闪过一个可怕的念头，令其浑身都为之一颤。他使劲地揉了揉眼睛，试图再一次将目光聚焦到手上。——那是一把刀，黑色的刀柄就握在他的手上，而短短的刀刃上淌着像血一样的东西。他的手颤抖起来，脑海中闪回式地浮现出了片段的记忆。那个女人一直在叫嚣。她说：“明天，你那副道貌岸然的嘴脸就会被公之于众。”她嘴角飞着唾沫，两只眼角向上吊起，之前看她还觉得娇媚可人，此时此刻却丑态毕露。她又说：“除非你帮我做一件事，我就保证永远闭嘴，绝不再给你惹任何麻烦。”

简介：AIM:ToexploretheinhibitoryeffectofasustainedcyclosporinA(CsA)deliverymicrosphere(CsA-MS)onposteriorcapsularopacification(PCO)inrabbiteyesaftercataractextraction.·METHODS:TwentyNewZealandwhiterabbitsacceptedcataractextractionplusintraocularlensimplantationandtheirlefteyeswereintraoperativelyinjectedCsA-MSpreparedusingpolymerpolylactioglycolicacid(PLGA)asacarrierandtheirrighteyeswereinjectedwithemptyMS.Thechangesincornea,anteriorchamberreaction,intraocularpressure,PCOandCsAconcentrationinaqueoushumorwereexaminedpostoperativelyandalltheeyeswereenucleated3monthsaftersurgeryforhistopathologicalandmorphologicalexaminationwithlightmicroscopyandelectronmicroscopy.·RESULTS:Conjunctivalhyperemia,cornealedema,intraocularpressureandanteriorchamberresponseofexperimentalandcontroleyesweresimilar,whilePCOinCsAMSinjectedeyeswasgreatlyimprovedcomparedwiththatincontroleyes.PosteriorcapsulesinCsA-MSinjectedeyesweresmoothandlensepithelialcells(LEC)didnotproliferatesignificantly(P>0.05),whileLECinposteriorcapsuleofcontroleyeshaddifferentdegreesofproliferationandcorticalregeneration.LECinCsA-MSinjectedeyeswerenotfunctionallyactiveandunderwentapoptosis,whereasLECincontroleyeswerefunctionallyactive(F-test,P=0.025).Inaddition,thecornealultrastructureshowednodifferencesbetweenCsA-MSandMSinjectedeyes.CONCLUSION:CsA-MShashighbioavailabilityinrabbiteyesandcouldinhibitpostoperativePCOoccurrenceanddevelopmentduringthestudyperiod,suggestingthatCsA-MSmaybeapromising,effectiveandsafeadministrationroutetopreventPCOinclinic.

简介：AIM:ToinvestigatetheeffectofY-27632onthesurvivalandneuriteoutgrowthoftheculturedretinalneurocytes.METHODS:Afterthepostnatalday2-3,Sprague-Dawleyretinalneurocyteswereculturedfor48hours,theculturemediawasreplacedwithserum-freemedia(controlgroup)andserum-freemediacontained30μmol/LY-27632(Y-27632group),andthecellswerecontinuallyculturedanother48hours.Theculturedretinalneurocyteswereidentifiedwithanti-neuronspecificenolase(NSE)immunocytochemistry.ThesurvivalstateofthosecellswasestimatedbyMTTassay,andtheneuriteoutgrowthofthosecellswasevaluatedbythecomputerizedimage-analysissystem.RESULTS:Comparedwiththecontrolgroup,theabsorbancevaluesofcellssurvivalinY-27632groupincreased12.90%and33.33%respectivelyafter72and96hoursculture.Y-27632hadnosignificanteffectonthediameterofculturedretinalneurocytes.Comparedwiththecontrolgroup,Y-27632inducedastableimprovementofneuriteoutgrowthofretinalneurocytesafter72and96hoursculture(P=0.001).CONCLUSION:Y-27632couldpromotethesurvivalandneuriteoutgrowthoftheearlypostnatalculturedretinalneurocytes.

简介：AIM:Toevaluatetheepidemiologic,anatomic,andclinicalfeaturesofopenglobeinjuriesinchildren.METHODS:Themedicalfilesofpatientsundertheageof16whohadbeenoperatedforanopenglobeinjuryatAkdenizUniversityHospital’sDepartmentofOphthalmologywereretrospectivelyevaluated.RESULTS:Atotalof90patientswereevaluatedinthisstudy.Amongthesepatients,26(28.9%)werefemaleand64(71.1%)weremale.Themeanageofthepatientswas7.7±4.2years.Themale/femaleratiowasobservedtoincreasewithincreasingage(P=0.006,P=7.48).Injuriesweremostlikelytooccurinspringandautumn(P=0.028).Thetimeintervalbetweentheinjuryandthesurgicalrepairwas9.36±27.4h.Forty(44.4%)oftheinjuriesoccurredinthehome,27(30%)occurredintheyard,and21(23.3%)happenedwhileplayinginthestreet.Themostcommoncausesofinjuryweresharpmetalobjects(P<0.001).Injurytothecorneaoccurredin47(52.2%)ofthepatients(P<0.001).Themostcommoncomplicationtooccurwascataractformation.Additionaloperationswerenecessaryfor37(41.1%)ofthepatients.Thefinalvisualacuitywascorrelatedwithboththeinitialvisualacuityofthewoundedeyepriortosurgeryandthelengthofthewound(P<0.001,r=0.502andP<0.001,r=-0.442,respectively).CONCLUSION:Openglobeinjuriesthataresufferedinchildhoodgenerallyoccureitherathome,intheyard,oronthestreet,withsharpmetalobjectsbeingthemostcommoncauseofinjury.Theinitialvisualacuityandthelengthofthewoundarethemostimportantdeterminantsofthefinalvisualacuity.

简介：AIM:Tocharacterizetemporalpatternofresolutionandrecurrenceofnaivechoroidalneovascularization(CNV)secondarytowetage-relatedmaculardegeneration(AMD)treatedwithintravitrealbevacizumabonasneededregimen,andtoanalyzebaselineriskfactorsforCNVresolutionorrecurrence.METHODS:Ninety-oneeyesof80patientswithnewlydiagnosedwetAMDwereretrospectivelystudied.Alleyesweretreatedwitharoundofthreemonthlyintravitrealbevacizumabinjections,followedbyoneadditional’bonus’injectionafterresolutionofCNVactivity.Duringfollow-up,eyesweremonitoredwithfluoresceinangiography,opticalcoherencetomography,andbest-correctedvisualacuity(BCVA).IncaseofrecurrencesofCNVactivity,eyeswereretreatedwithotherroundsofbevacizumabinjectionsfollowingthesametreatmentprotocol.RESULTS:Overamedianfollow-upof532d,themedianresolutiontimeofCNVactivityinthefirst,second,andthirdtreatmentroundwas98d,126d,and111d,respectively.Themedianrecurrencetimeforthethreeroundswas154d,126d,and151d,respectively.Nosignificantdifferenceinresolutiontime(P=0.09)orinrecurrencetime(P=0.11)wasdetectedamongtreatmentrounds.Age(P=0.0082)andlensstatus(P=0.035)werefoundtobeassociatedwithCNVresolution;forevery1-yearincreaseinagetherewas4%greaterchanceofCNVresolution;Phakiceyesdemonstrateda33%betterchancetoexperienceCNVresolutionthanpseudophakiceyes.ForCNVrecurrence,lensstatus(P=0.0009)andgender(P=0.0446)werefoundtobepredictive;pseudophakiceyeshada3.69-foldgreaterrisktoexperiencerecurrenceofCNVactivitycomparedtophakiceyes;maleshada2.19-foldgreaterrisktoexperiencerecurrenceofCNVactivitythanfemales.NosignificantBCVAchangesamongthreetreatmentroundswerenoted(P=0.56).CONCLUSION:ResolutiontimeandrecurrencetimeofCNVactivitywerenotsignificantlydifferentamongtreatmentrounds,suggestingabsenceoftachyphylaxistobevacizumab.Acautiousdecisionshouldbemadeupondisco

简介：AIM:ToevaluatetheefficacyofSeprafilmtransplantationfollowingadhesiolysisforpreventingpostoperativereadhesionandimprovingsurgicaloutcomes.METHODS:Primaryblepharoplastywascarriedoutonbotheyelidsof18albinorabbits.After2weeks,anewskinincisionwasmade,andadhesiolysiswasperformedonbotheyelids.Therabbitswerecategorizedintotwogroups,onewithadhesiolysisaloneinthelefteyelid(controlgroup),andtheotherwithadhesiolysiswithaSeprafilmgraftintherighteyelid(Seprafilmgroup).Thedegreesofinflammationandfibrosiswereexaminedwithhematoxylin-eosin(HE)andMasson’strichromestains.Expressionofα-smoothmuscleactin(α-SMA)wasalsoimmunohistochemicallyexamined.RESULTS:Eyelidexaminationimmediatelyaftertheoperationrevealedmildswellingandhemorrhageinbothgroups,butthesesymptomsresolvedafter1week-2weeks,andeyelidshapehadrecoveredcompletelyinbothgroups.MicroscopicassessmentsdemonstratedthattheSeprafilmgroupshowedlessinflammationandfibrosisthanthecontrolgroup.TheSeprafilmgroupalsoexhibitedfewerα-SMA-positivecellsthanthecontrolgroup.CONCLUSION:Basedonthesefindings,weconcludethatSeprafilmgraftwithadhesiolysisisaneffectivemethodforpreventingpostoperativereadhesionsaftereyelidsurgery.

简介：AIM:ExcessivedissolveofcornealtissueinducedbyMMPswhichwereactivatedbycytokinsandchemokineswillleadtocornealulcer.ThemolecularmechanismofLipoxinA4(LXA4)oncornealcollagendegradationinthreedimensionswasinvestigated.·METHODS:Rabbitcornealfibroblastswereharvestedandsuspendedinserum-freeMEM.TypeIcollagen,DMEM,collagenreconstitutionbufferandcornealfibroblastsuspensionweremixedonice.Theresultantmixturesolidifiedinanincubator,afterwhichtestreagentsandplasminogenwasoverlaidandthecultureswerereturnedtotheincubator.Thesupernatantsfromcollagengelincubationswerecollectedandtheamountofhydroxyprolineinthehydrolysatewasmeasured.ImmunoblotanalysisofMMP-1,-3andTMMP-1,-2wasperformed.MMP-2,-9wasdetectedbythemethodofGelatinzymography.Cytotoxicityassaywasmeasured.RESULTS:LXA4inhibitedcornealcollagendegradationinadoseandtimemanner.LXA4inhibitedtheIL-1βinducedincreasesinthepro-MMP-1,-2,-3,-9andactiveMMP-1,-2,-3,-9inaconcentrationdependentmanner.LXA4alsoinhibitedtheIL-1βinducedincreasesinTIMP-1,-2.CONCLUSION:Asapotentanti-inflammationreagent,LXA4caninhibitcornealcollagendegradationinducedbyIL-1βincornealfibroblaststhusinhibitingcornealdissolvingpathologyprocess.