简介:摘要目的探讨乳腺影像报告和数据系统(BI-RADS)对钙化的评估分类及临床应用价值。方法以美国放射协会的第4版乳腺影像报告和数据系统(BI-RADS)为准,对2012年4月-2014年9月间145例乳腺钙化疾病进行BI-RADS分类,同时利用强生麦默通活检系统,对乳腺钙化病变进行穿刺活检术,术后标本摄影,并与病理结果对照研究,总结分析乳腺良性、恶性钙化的X线形态和分布特点。结果145例乳腺钙化病变中,良性65例,恶性80例。良性钙化中以簇状和弥漫分布点状钙化占多数,均为16.92%(11/65);恶性钙化中以节段性分布的分支杆状钙化为主,占22.50%(13/80)。结论钙化的形态、分布对鉴别乳腺良性及恶性病变具有一定的价值。
简介:摘要目的对超声征象在诊断BI-RADS4级乳腺病变中应用给予探讨。方法随机选取我院2013年8月至2014年9月收治的乳腺癌病变患者204例患者,根据患者临床表现不同将所有患者分为两组,第一组患者由78例乳腺癌患者组成,第二组患者由126例乳腺良性肿瘤组成,分析比较两组患者的超声特征,比如肿瘤的纵横比、边界、形态等,比较两组患者超声征象的准确性、特异性及敏感性。结果超声征象在良恶性肿瘤的诊断上具有较高的鉴别能力,在诊断上具有较高特异性的有动脉血流RI≥0.7、异常高回声晕、毛刺装边缘,在诊断乳腺癌中特异性分别为90.5%、100%、99.2%。结论在诊断BI-RADS4级乳腺病变时,其中有3个超声征象可以作为恶性肿瘤的疑似特征,分别为动脉血流RI≥0.7、异常高回声晕、毛刺装边缘,在治疗中建议使用手术方法。
简介:Thetraditionalproportionalsolenoidhasdisadvantages,suchasbigsizeanddifficultyremoving.Sothispaperintroducesanewtypeofbi-directionalproportionalsolenoid,andexpoundsthestructureandworkingprincipleindetail.Onthisbasis,themathematicalmodeloftheproportionalsolenoidisestablished,anditsoutputcharacteristicisanalyzedbythefiniteelementtoolAnsoft/Maxwell.Itsstructureparameters'influenceontheoutputcharacteristicalsoisdiscussedthroughtheelectromagneticfieldanalysis.Thesimulationresultsshowthatthisnewtypeofbi-directionalproportionalsolenoidcanobtainagoodstaticcharacteristicwithoutthesamemagneticcircuitcontrolofthetraditionalproportionalsolenoid.
简介:研究Sb元素含量对Sn-Bi系焊料性能的影响。通过差示扫描量热法研究Sn-Bi-Sb焊料的熔化行为。采用铺展实验研究焊料在Cu基板上的润湿性。测试Sn-Bi-Sb/Cu结合界面的力学性能。结果表明:三元合金中含有包共晶反应形成的共晶组织,随着Sb含量的增加,共晶组织增多;在加热速率为5℃/min的条件下,三元合金显示出更高的熔点和更宽的熔程;添加少量Sb对Sb-Bi系焊料的铺展率有影响;在焊料铺展过程中形成反应过渡层,反应过渡层中存在Sb元素而无Bi元素,过渡层厚度随着Sb元素含量的增加而增大。Sn-Bi-Sb焊料的剪切强度随着Sb元素含量的增加而升高。
简介:Asoneofcandidatesforthefuelcladdingorstructurematerialusedinfourthgenerationfissionandfusiondemonstratereactor,MAXphasehasthepropertiesofbothceramicandmetal,suchashighmeltingpoint,hightemperaturestability,gooderosionresistanceandradiation-damagetolerance[1;2].Maxphaseisaseriesofceramicsofnanolamellarandhexagonalstructure.Mrepresentstransitionelement.Arepresentsthethirdorfourthmaingroupelement.XrepresentNandC.Inthedesignoflead-cooledfastreactor,itisrequiredthatthematerialshouldendurethecorrosionofliquidPb-Bialloy.Therefore,understandingoftheoxidelayersandtheirgrowthmechanismsinLBEisfundamentallyimportantforthedevelopmentofcandidatematerials.
简介:Thispaperdealswithabi-extrapolatedsubgradientprojectionalgorithmbyintroducingtwoextrapolatedfactorsintheiterativesteptosolvethemultiple-setssplitfeasibilityproblem.Thestrategyisintendtoimprovetheconvergence.Anditsconvergenceisprovedundersomesuitableconditions.Numericalresultsillustratethatthebi-extrapolatedsubgradientprojectionalgorithmconvergesmorequicklythantheexistingalgorithms.
简介:Carbazole-basedbi-functionalphotorefractivepolyacrylateswerepreparedviafreeradicalpolymerizationandpost-azo-couplingreaction.ThestructureofpolymerswascharacterizedbyFouriertransforminfraredspectroscopy(FTIR)andprotonnuclearmagneticresonance(1H-NMR)spectroscopy.Thedifferentialscanningcalorimetry(DSC)andthethermalgravimetricanalysis(TGA)wereusedtocharacterizethethermalpropertyofpolymers.Theresultsindicatethatthoughtheglasstransitiontemperature(Tg)ofpolymersincreaseswithincreasingtheratioofNLOgroups,thepolymerswithdifferentratiosofNLOgroupsstillallshowlowglasstransitiontemperaturesaround60°C,andgoodthermalstability,whicharefavorabletothepracticalapplicationofthesepolymers.Thegelpermeationchromatographic(GPC)resultindicatesthatthesepolymersallhavehigh-molecular-weightwhichisfavorabletothelongtermstabilityofthematerial.Further,thesepolymershavegoodsolubilityinchloroformsolvent,andthesolutionscaneasilybefabricatedintoopticallytransparentfilms.Gaincoefficientsof75cm-1,185cm-1and66cm-1canbeobservedatzeroexternalelectricfieldwithoutanyadditionagentorpre-polingforpolymersP-2,P-3andP-4respectively.ThedifferentcontentsofNLOgroupsresultinthedifferentpropertiesofpolymersP-2,P-3andP-4.
简介:Anefficientsynthesisoffunctionalized4H-chromenesbythetandemreactionofb,g-unsaturatedaketoesterswith2-naphthols,1-naphthols,and1,3-dihydroxynaphthaleneshasbeenaccomplishedwithhighselectivityandexcellentyieldsinthepresenceofacatalyticamountofbismuthtriflate[Bi(OTf)3,5mol%]undermildconditions.Thefunctionalized4H-chromenesynthesisandourprevious2Hchromenehemiacetalsynthesiscouldcomplementeachothertoenrichreactiondiversity.
简介:采用溶胶-凝胶法制备了Pt/Bi3.15Nd0.85Ti3O12/SrTiO3/Si多层电容即金属-铁电层-绝缘层-半导体结构,并对其电学性能进行了测试与分析。获得的存储窗口电压约为2.5V,漏电流密度低于10-8A·cm-2,保持时间达7.5h以上。制备的SrTiO3薄膜表现出较高的介电性和较好的绝缘性。