We use the first arrival traveltime to correct the phase distortion in a nonlinear wave equation inversion scheme.This improves the precision of tomographic reconstruction of a velocity structure with large variations...We use the first arrival traveltime to correct the phase distortion in a nonlinear wave equation inversion scheme.This improves the precision of tomographic reconstruction of a velocity structure with large variations and helps solve the ill-posed problem of wave equation inversion.When the variation of the velocity distribution is large,general non-linear wave equation inversions are very ill-posed and for such strong nonlinear we can not obtain a correct inversion.One of main reasons is that the calculated and observed phase of the wavefield differs greatly if the initial model is far from the true model.This leads to highly mismatched phase between the calculated and the observed wave field.This is so-called"Cycle Skipping"problem in the full waveform inversion.The phase mismatch is even more pronounced if a high operating frequency is employed in order to increase resolution.To address this problem,we use the first arrival to"demodulate"the wave field in the frequency domain with a goal of restoring the phase of wave field.Then we minimize an objective function consisting of so called"demodulated"wave field to solve wave equation inversion problem.In this way,we find that the inversion is much improved,and when the velocity perturbation in a complicated model reaches 35%,we can still obtain a good inversion.A computer simulation shows that our method is very robust for acoustical wave inversion with good reconstruction precision.展开更多
目的 了解黄精叶绿茶主要香气成分,探明黄精叶绿茶和龙井绿茶的香气成分差异。方法 采用全二维气相色谱-飞行时间质谱法(comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry,GC×GC-TOF MS)分析...目的 了解黄精叶绿茶主要香气成分,探明黄精叶绿茶和龙井绿茶的香气成分差异。方法 采用全二维气相色谱-飞行时间质谱法(comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry,GC×GC-TOF MS)分析两种绿茶香气成分组成与相对含量。结果 两种绿茶共鉴定出332种成分,归属为醇、酮、饱和烷烃、烯烃、醛、酯、吡嗪、芳烃、酸、胺、醚、环氧烷、环烷烃、酚、呋喃、呋喃酮、酰胺、吡咯啉、酸酐、硫化物、卤代烃、含氮化合物、含氧化合物、杂环化合物、氮氧化物等26类化合物。黄精叶绿茶鉴定出225种挥发性成分,龙井绿茶鉴定出200种挥发性成分,共有成分93种。醇类均为含量最高的种类,占黄精叶绿茶香气总含量的26.47%,占龙井绿茶香气总含量的30.94%。黄精叶绿茶的醛类含量仅次于醇类,占21.75%,而龙井绿茶的烯烃类含量仅次于醇类,占14.33%。结论 38种挥发性化合物在二者中相对含量较高,其中戊醇、苯甲醇、苯甲醛在黄精叶绿茶中相对含量较高,对其香气品质可能具有直接影响。与之不同的是,龙井绿茶中反式-2-戊烯-1-醇、(R)-1-甲基-5-(1-甲基乙烯基)环己烯等挥发性化合物相对含量较高。同时相对含量不高的低阈值挥发性化合物也可能是形成黄精叶绿茶香型的关键香气(如α-紫罗兰酮等)。这有利于后续深入研究黄精叶绿茶香气成分的化学组成,为黄精叶制成茶叶提供数据支持。展开更多
目的探讨SOX10在三阴性基底样型乳腺癌诊断中的潜在临床应用价值。方法选取2019年1月~2019年12月在重庆医科大学附属第一医院病理科首次确诊为乳腺癌的患者组织样本171例,按照免疫组化分子分型,分为三阴性基底样型、三阴性非基底样型、L...目的探讨SOX10在三阴性基底样型乳腺癌诊断中的潜在临床应用价值。方法选取2019年1月~2019年12月在重庆医科大学附属第一医院病理科首次确诊为乳腺癌的患者组织样本171例,按照免疫组化分子分型,分为三阴性基底样型、三阴性非基底样型、LuminalA型、Luminal B HER2阴性型、Luminal B HER2阳性型、HER2阳性型,对所有样本进行SOX10免疫组化检测,分析SOX10的表达与分子分型的相关性。用受试者工作特征曲线(ROC)评估该指标的特异性及敏感性。结果SOX10在三阴性基底样型、三阴性非基底样型、LuminalA型、Luminal B HER2阴性型、Luminal B HER2阳性型、HER2阳性型中的阳性率分别为80.9%(38/47)、42.9%(3/7)、0.0%(0/28)、0.0%(0/44)、0.0%(0/17)、3.6%(1/28)。与其它分子分型相比,三阴性基底样型乳腺癌中SOX10表达明显升高(P<0.005)。SOX10作为标志物诊断三阴性基底样型乳腺癌的ROC曲线下面积为0.888。结论SOX10在三阴性基底样型乳腺癌中特异性高表达,可能成为该疾病的诊断指标和潜在治疗靶点。展开更多
基金supported by the Seismic Tomography Project of Stanford University,a research consortium sponsored by companies of the oil and gas industry
文摘We use the first arrival traveltime to correct the phase distortion in a nonlinear wave equation inversion scheme.This improves the precision of tomographic reconstruction of a velocity structure with large variations and helps solve the ill-posed problem of wave equation inversion.When the variation of the velocity distribution is large,general non-linear wave equation inversions are very ill-posed and for such strong nonlinear we can not obtain a correct inversion.One of main reasons is that the calculated and observed phase of the wavefield differs greatly if the initial model is far from the true model.This leads to highly mismatched phase between the calculated and the observed wave field.This is so-called"Cycle Skipping"problem in the full waveform inversion.The phase mismatch is even more pronounced if a high operating frequency is employed in order to increase resolution.To address this problem,we use the first arrival to"demodulate"the wave field in the frequency domain with a goal of restoring the phase of wave field.Then we minimize an objective function consisting of so called"demodulated"wave field to solve wave equation inversion problem.In this way,we find that the inversion is much improved,and when the velocity perturbation in a complicated model reaches 35%,we can still obtain a good inversion.A computer simulation shows that our method is very robust for acoustical wave inversion with good reconstruction precision.
文摘目的探讨SOX10在三阴性基底样型乳腺癌诊断中的潜在临床应用价值。方法选取2019年1月~2019年12月在重庆医科大学附属第一医院病理科首次确诊为乳腺癌的患者组织样本171例,按照免疫组化分子分型,分为三阴性基底样型、三阴性非基底样型、LuminalA型、Luminal B HER2阴性型、Luminal B HER2阳性型、HER2阳性型,对所有样本进行SOX10免疫组化检测,分析SOX10的表达与分子分型的相关性。用受试者工作特征曲线(ROC)评估该指标的特异性及敏感性。结果SOX10在三阴性基底样型、三阴性非基底样型、LuminalA型、Luminal B HER2阴性型、Luminal B HER2阳性型、HER2阳性型中的阳性率分别为80.9%(38/47)、42.9%(3/7)、0.0%(0/28)、0.0%(0/44)、0.0%(0/17)、3.6%(1/28)。与其它分子分型相比,三阴性基底样型乳腺癌中SOX10表达明显升高(P<0.005)。SOX10作为标志物诊断三阴性基底样型乳腺癌的ROC曲线下面积为0.888。结论SOX10在三阴性基底样型乳腺癌中特异性高表达,可能成为该疾病的诊断指标和潜在治疗靶点。
