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3 个结果
  • 简介:Ahighlyefficientflowdischargemeasuringmethodwasproposedinthisstudy.EitherthetraditionalvelocimetersortheAcousticDopplerProfiler(ADP)canbeusedtomeasurethemaximumflowvelocity,Umaxatthey-axis(verticalpassingthroughthemaximumpointvelocityinachannelcrosssection).Themeanvelocityofthecrosssection(U)wascomputedbyφUmax,whereφwasestimatedfromthefielddatacollectedwiththecup-typecurrentmeterusingthe"two-pointmethod".Theflowdischargewasthencomputedbymultiplyingtheestimatedflowareawith(U).Incontrasttothetraditionalmethod,whereflowdepthandflowvelocitymeasurementsareneededforeachvertical,theproposedmethodhastheadvantagesofshortoperationtimeandhighaccuracy.Thesefeaturesareespeciallyimportantforthemeasurementofunsteadyflow.

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  • 简介:沉积氧需求(草皮)是为水质量分析并且为在河,湖,河口和海湾里当模特儿的水质量的一个关键参数。草皮能在实验室并且在situ被测量。然而,在里面situ技术看起来是为测量草皮,,的更好的途径它可能提供更代表性、精确的结果。以便优化设计在situ草皮测量房间,在圆柱的草皮测量房间的三维的流动地,通常使用为在situ大小,被使用基于RNG的k-数字地模仿了两倍方程骚乱模型。有三种不同流入管子配置的草皮房间被调查。结果证明那房间III在另外的图案上介绍明显的优点为在situ草皮测量,因为好流动混合能被完成,底部沉积暂停能在房间被避免。数字模拟结果被比较验证,存在结果源于实验室实验。设计反映数字模拟的结果的草皮测量房间成功地被测试为在新鲜、盐的水里的situ草皮大小。

  • 标签: 氧量测量 原位测量 优化设计 商会 超氧化物歧化酶 沉积物
  • 简介:Inthisstudy,thepracticalmethodologiesaredescribedforthedeterminationofthefactorsfortheselfabsorptioneffect(Fs),spectralinterferences(Fcsi),andtruecoincidencesummingeffects(Fcoi),whichareusedindirectgamma-spectrometricmeasurementofradionuclidessuchas210Pb,238U,234Th,226Ra,214Pb,228Ac,208Tl,214Bi,137Csand40Kinsamples.Tovalidatetheappliedmethods,certifiedreferencematerials(CRMs)oflakeandstreamsedimentsweremeasuredwithann-typeGermanium(Ge)detector-calibratedusingamultinuclidereferencesource.Thehighestself-absorptioncorrectionfactorsrangedfromFs1.44-2.10for46.5keVpeak(210Pb)andFs?1.25-1.60for63.3keVpeak(234Th)lyinginthelowenergyregionofthespectrum.Thesystematicinfluencewasobservedfor186.2keV(226Ra)peakduetospectralinterferenceswiththe235Ucontribution.Forthispeak,Fcsiischangedfrom0.921to0.955.Additionally,thepresentstudysuggeststhattruecoincidencesumming(TCS)effectsarenotdominant,exceptfor208Tland214BiforwhichFcoirangedfrom1.179to1.192anrangedfrom1.140to1.151,respectively.

  • 标签: Correction factor SELF-ABSORPTION Spectral interference TRUE