Laser pulse nonlinear transmission measurements through saturable absorbers of known absorption parameters allow the measurement of their energy density. On the other hand, nonlinear transmission measurements of laser...Laser pulse nonlinear transmission measurements through saturable absorbers of known absorption parameters allow the measurement of their energy density. On the other hand, nonlinear transmission measurements of laser pulses of known energy density through absorbing media allow their absorption parameter determination. The peak energy density w0P of second harmonic pulses of a mode-locked titanium sapphire laser at wavelength λP = 400 nm is determined by nonlinear energy transmission measurement TE through the dye ADS084BE (1,4-bis(9-ethyl-3-car-bazovinylene)-2-methoxy-5-(2’-ethyl-hexyloxy)-benzene) in tetrahydrofuran. TE(w0P) calibration curves are calculated for laser pulse peak energy density reading w0P from measured pulse energy transmissions TE. The ground-state absorption cross-section σP and the excited-state absorption cross-section σex at λP, and the number density N0 of the retinal Schiff base isoform RetA in pH 7.4 buffer of the blue-light adapted recombinant rhodopsin fragment of the histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii were determined by picosecond titanium sapphire second harmonic laser pulse energy transmission measurement TE through RetA as a function of laser input peak energy density w0P. The complete absorption cross-section spectrum展开更多
文摘对一种降水预报跨量级通用综合评价方法(precipitation accuracy score,PAS)进行了邻域法改进。改进方案通过预报与观测资料匹配技术,采用距离权重评分统计方法,旨在减轻双重惩罚问题,同时确保评分系统能合理表征位置预报的准确性。研究应用邻域PAS方法,基于2021年汛期中国气象局智能网格实况产品,对江苏本地精细化天气分析预报系统进行整体和典型个例检验,同时引入均方根误差(root mean square error,RMSE)、结构相似性(structural similarity,SSIM)、峰值信噪比(peak signal-to-noise ratio,PSNR)、概率空间中的稳定公平误差(stable equitable error in probability space,SEEPS)等跨量级检验指标进行了对比。结果表明,邻域PAS方法显著回避了原方法在位置预报上的双重惩罚问题,更符合预报人员的主观预期和预报应用服务的要求,具有明显优势。邻域PAS评分、PAS评分与现有多个跨量级指标均表现出良好的相关性,多方验证了方法的有效性。同时,相较于RMSE,该方法更有效地平衡了对不同量级降水的敏感性;而与SSIM和PSNR相比,则展现了更强的可解释性,多个个例显示评分结果更符合预报员的认知。邻域PAS方法相比于SEEPS技巧评分保留了对大量级降水的检验分辨能力,同时减轻了PAS方法检验大量级降水产生的严重双重惩罚,一定程度平衡了大量级降水检验的两难问题。
文摘Laser pulse nonlinear transmission measurements through saturable absorbers of known absorption parameters allow the measurement of their energy density. On the other hand, nonlinear transmission measurements of laser pulses of known energy density through absorbing media allow their absorption parameter determination. The peak energy density w0P of second harmonic pulses of a mode-locked titanium sapphire laser at wavelength λP = 400 nm is determined by nonlinear energy transmission measurement TE through the dye ADS084BE (1,4-bis(9-ethyl-3-car-bazovinylene)-2-methoxy-5-(2’-ethyl-hexyloxy)-benzene) in tetrahydrofuran. TE(w0P) calibration curves are calculated for laser pulse peak energy density reading w0P from measured pulse energy transmissions TE. The ground-state absorption cross-section σP and the excited-state absorption cross-section σex at λP, and the number density N0 of the retinal Schiff base isoform RetA in pH 7.4 buffer of the blue-light adapted recombinant rhodopsin fragment of the histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii were determined by picosecond titanium sapphire second harmonic laser pulse energy transmission measurement TE through RetA as a function of laser input peak energy density w0P. The complete absorption cross-section spectrum
