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11 个结果
  • 简介:Introduction:Frequencydoublingtechnology(FDT)providesascreeningprogramforthedetectionofglaucomatousopticnervedamage.Theexaminationtimeusingthisprogramisveryshort,lessthanoneminutepereye.High-passresolutionperime-try(HRP)isknowntobesensitiveforearlyglaucomadamageandhasbeenreportedtodetectchangeearlier,thanconvention-

  • 标签: 双倍增频技术 FDT 青光眼 筛检 视神经损害
  • 简介:作者为可能非加倍,但是满足某些生长条件的氡措施给Morrey空格的一个自然定义,并且在泛音分析和他们的珍视向量的扩展在一些古典操作符的这些空格调查围住的海角。

  • 标签: MORREY空间 双重测量 向量值 清晰度 有界性
  • 简介:利用不同浓度的秋水仙碱和不同处理方式来处理毛白杨及其杂种毛新杨的雄花芽,可以获得一定比率的染色体未减数的大花粉粒.用细胞荧光测定技术测定其DNA相对含量,鉴定了这种大花粉粒为2n花粉粒.这种2n花粉粒是具有生活力的,可用于授粉杂交来培育三倍体.在温度较低的条件下,当秋水仙碱浓度为0.1%~0.5%时,注射处理花芽3~6次效果最佳.对高温(38~40℃)处理花芽诱导2n花粉粒的方法也进行了试验和分析.

  • 标签: 毛白杨 毛新杨 秋水仙碱 染色体加倍 2n花粉粒
  • 简介:Anall-solid-statesingle-frequency1064nmlaserwitha100μspulsewidth,500Hzrepetitionrateand700mJsinglepulseenergyisdesignedusingseedinjectionandathree-stagemasteroscillatorpoweramplifier(MOPA)construction.Usingthisasabasis,researchonlong-pulselaserfrequencydoublingiscarriedout.Bydesigningandoptimizingthelithiumtriborate(LBO)crystal,thetheoreticallycalculatedmaximumconversionefficiencyηmaxreaches68%atM2=1,whileηminis33%atM2=3.Generationof212mJpulsesofgreenlightwitharepetitionrateashighas500Hzisobtainedfromafundamentalenergyof700mJ.Theexperimentalconversionefficiencyreaches31%andthepowerstabilityisbetterthan±1%.

  • 标签: ALL-SOLID-STATE frequency doubling MOPA construction SINGLE-FREQUENCY
  • 简介:Wereportonanall-solid-statehigh-powerquasi-continuousbluelightsourcebythefrequencydoublingofasignalwavefromanopticalparametricoscillator(OPO).A50-mm-longLiB305(LBO)crystalisusedfortheOPO,whichispumpedbyadiode-pumpedNd:YAGgreenlaser(1OkHz,50ns).TunableblueemissioninanewnonlinearcrystalBiB306(BiBO)isobtainedwithawavelengthrangefrom450to495nm.Theaveragepowerofthesignaloutputisashighas9.3Wfrom924to970nm.Themaximumoutputofthebluelaserwiththesecondharmonicwalk-offcompensationis1.3Waveragepowerat470nmfor6.2WofOPOsignallightat940nm.

  • 标签: 高能蓝光产生 高密度光存储 蓝色激光 倍频 光参量振荡器 LiB3O5晶体
  • 作者: Zhou Lei Liu Jiang-Mei Dong Xiao-Ping McGoogan Jennifer M. Wu Zun-You
  • 学科: 医药卫生 >
  • 创建时间:2020-08-10
  • 出处:《贫困所致传染病(英文)》 2020年第03期
  • 机构:Public Health Emergency Center, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China,National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China,Global Health Center, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China,National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
  • 简介:AbstractBackground:As COVID-19 makes its way around the globe, each nation must decide when and how to respond. Yet many knowledge gaps persist, and many countries lack the capacity to develop complex models to assess risk and response. This paper aimed to meet this need by developing a model that uses case reporting data as input and provides a four-tiered risk assessment output.Methods:We used publicly available, country/territory level case reporting data to determine median seeding number, mean seeding time (ST), and several measures of mean doubling time (DT) for COVID-19. We then structured our model as a coordinate plane with ST on the x-axis, DT on the y-axis, and mean ST and mean DT dividing the plane into four quadrants, each assigned a risk level. Sensitivity analysis was performed and countries/territories early in their outbreaks were assessed for risk.Results:Our main finding was that among 45 countries/territories evaluated, 87% were at high risk for their outbreaks entering a rapid growth phase epidemic. We furthermore found that the model was sensitive to changes in DT, and that these changes were consistent with what is officially known of cases reported and control strategies implemented in those countries.Conclusions:Our main finding is that the ST/DT Model can be used to produce meaningful assessments of the risk of escalation in country/territory-level COVID-19 epidemics using only case reporting data. Our model can help support timely, decisive action at the national level as leaders and other decision makers face of the serious public health threat that is COVID-19.

  • 标签: Seeding time Doubling time Case report Risk assessment SARS-CoV-2 COVID-19