查询词典 spectral

Detailed contents are given as follows:(1)In views of the x-ray laser target chamber on the SG-II high-power laser facility and the experimentally physical demands, the key influencing factors, such as the elliptical eccentricity and the spectral detection angle, on the angular dispersion, the spectral resolution,and the photometric parameter were studied by the elliptical self-focusing geometric principle. In order to increase the spectral and spatial resolution, using ray tracing code and optical path function, optimization calculation was carried out for an elliptical crystal spectrometer.

进一步以此为核心开发出了一种新型的X射线测量与诊断系统，取得了一些新的科研成果，可为王王淦淦昌昌院士、王大珩院士二老倡导研制成的用于国防科研、激光惯性约束聚变、强激光与物质相互作用、X射线激光等物理研究的大型钕玻璃高功率"神光II"激光装置上的物理实验提供更有效的诊断X射线谱手段，扩充了其应用范围，也对激光等离子体辐射keV以上能区段的X光发射和吸收的原子物理过程与机制、占据动力学、谱形态结构等方面做了深入一步的理论和实验研究。

Contrasting the number of arithmetic operations of the above two methods, it is shown that the reconstruction in time domain method is superior to the Spectral-Fit method.

最后通过对两者运算量的分析，指出时域重构法优于Spectral-Fit法。

In order to represent accurately and concisely the changing characteristics of one-dimensional spectrum density function in the chatter development. This thesis, for the first time, proposes the Edgeworth asymptotic expansion formulas of spectral density. A detailed proof is given. Some new statistic including spectral skewness, spectral kurtosis and spectral cumulants are proposed.

为了准确、简洁地表达一维谱密度函数在切削颤振建立过程中的变化特征，论文首次建立了一维谱密度函数的Edgeworth渐近谱展开式，给出了详细的证明；并由此提出了"谱偏态系数"、"谱峰态系数"和"谱累积量函数"等新的谱统计量。

Spectral element methods for partial differencial equation is introduced in this study from viewpoint of the collocation approximation of Chebyshev polynomial. Wave Equation and its space discretization are deduced. Two time integral methods, central difference method and implicit Newmark method, are introduced, and their stability and applicability are also discussed in some details. The significance of absorbing boundary conditions in spectral element methods for Aeroacoustics is explained, and Clayton-Engquist-Majda absorbing boundary conditions is emphasized and introduced, then the discrete scheme of this boundary conditions is deduced and applied to spectral element methods for wave equation.

本文从Chebyshev多项式逼近理论出发，详细介绍了谱元方法求解偏微分方程的过程；推导了流体中的声波动方程并在空间上对其进行了谱元离散；详细讨论了两种时间积分方法──中心差分法和Newmark方法，分析了它们的稳定性条件，并从理论上对比了两种方法的优缺点和适用范围；将吸收边界条件推广应用于谱元方法求解气动声学问题中，重点介绍了Clayton-Engquist-Majda吸收边界条件的原理和公式，推导了该吸收边界条件的变分形式，并将其引入波动方程的离散形式中。

The influences of the shock thickness and Alfven waves on the particle acceleration by diffusive shock waves are numerically studied through solving one-dimensional diffusive equation including the second-order Fermi effect. It is shown that the spectral index of the energetic particles strongly depends on the shock thickness. For example, the spectral index increases from 2.1 to 3.7 in the low energy range of 3-10 MeV and from 2.5 to 5.0 in the high energy range of 20-60 MeV as the thickness increases. The spectral index decreases from 4.3 to 3.1 as the particle injection energy increases. The spectral index decreases from 4.0 to 1.8 at the quasi-steady stage with the enhancement of the compression ratio from 2 to 4. The results indicate that under the influence of Alfven waves, the energetic particle spectrum at lower energy becomes flat and the spectral index decreases from 2.5 to 0.6 in the low energy range of 3-10 MeV and from 11.6 to 5.0 in the high energy range of 20-60 MeV. At the same time, the rollover energy reaches 19.6 MeV. The spectral index decreases from 5.8 to 2.9 as the energy density of Alfven waves increase. All these results are basically consistent with the theoretical models, as well as the observations of typical energetic particle events.

通过数值求解包含二阶费米加速的一维扩散方程，探讨在准平行激波条件下激波厚度和级联阿尔芬波对粒子加速的影响，研究粒子分布函数的演化与激波厚度和阿尔芬波强度的内禀关系，计算结果表明：(1)考虑激波厚度时，谱指数明显依赖于激波厚度，随着厚度从0.32增大到2.56，低能端(3-10MeV)谱指数逐渐从2.1增加到3.7，高能端(20-60MeV)谱指数从2.4增大到5.0，能谱逐渐变软；当初始注入粒子动量增大1.3倍，质子能谱指数从4.3减小到3.1，且与零厚度激波加速的谱指数差值缩小；厚度不变时，随着压缩比从2增加到4，准稳态分布时低能端(3-10MeV)粒子能谱指数逐渐从4.0减小到1.8谱变硬；(2)在级联阿尔芬波的影响下，随着时间的增大，粒子在低能处(3-10MeV)的谱指数从2.5减小到0.6高能端(20-60MeV)谱指数从11.6减小到5.0，能谱变硬，拐点能量值从7.5MeV增大到为19.6MeV；随着波的能量密度增大，谱指数从5.8减小到2.9，这表明阿尔芬波强度越大，加速效率越高，通过与激波厚度解析结果和高能粒子事件的观测能谱比较发现两者是一致的，说明数值模拟结果是可靠的。

This retrospective study included three medical institutes and fifty-nine patients of Alzheimer's disease. Based on spectral analysis, we calculated and presented spectral profile、power ratio、interhemispheric alpha coherence and intrahemispheric alpha coherence of individual EEG.

本研究收集三个专科医疗机构、59 位阿兹海默病患的数位脑波资料，利用频谱分析计算并呈现 spectral profile、power ratio、interhemispheric alpha coherence 和 intrahemispheric alpha coherence 等指标。

The following results are made from this research: Assessing data quality and band combination of different bands in line with geo-target features in desertification areas, and determining basic bands for desertification monitoring. And understanding and studying the spectral features and variation rules of geo-targets in the experimental area, raising that it is the basis of geo-targets information collection with imaging spectrometer data to understand spectral features and variation rules of geo-targets, realizing that in a great extent spectral-integrated-form-based classification method can remove the phenomenon of "different spectrum with same objects" resulted from reflection ratio curve translation because of the angle change among sensor, targets and observation direction, and the average and variance images can be introduced to solve the problem of two kinds of geo-target with similar spectral forms and much different values of whole reflectionratio. It is suggested that "red edge" range bands of vegetation, which has close relationship with vegetation cover and biomass, is the main characteristic bands and important basis for careful vegetation classification and quantitative retrieval, and pixel-based derivative spectral analysis is very useful for removing the effects of soil background values and quantitatively retrieving vegetation biomass and cover. The remote sense quantitative retrieval model is developed for main appraisable factors of desertification monitoring assessment with imaging spectrometer data and then the applicability of model is analyzed.

研究结果如下：首先针对荒漠化地区的地物特征，对高光谱数据不同波段的数据质量、波段组合进行了评价，提出了适用于荒漠化监测的基本波段选择集；初步了解和掌握了研究地区的地物光谱特性及变异规律，进一步明确了掌握地物光谱特征和变异规律是用成像光谱仪数据提取地物信息的基础；发现了基于光谱整体形状的分类方法在很大程度上能够消除由于传感器、地物目标观测方向之间的角度变化引起的反射率曲线整体平移的"同物异谱"现象，对于谱形相似而整体反射率的值相差较大的两类地物，通过引入均值和方差图像参与分类得到解决；研究还表明在植被"红边"范围内的波段是进行荒漠化监测的主要特征波段，这些波段与植被生物量和盖度都有密切的关系，是开展精细植被分类研究和植被定量反演的重要基础；像元的导数光谱分析可以消除土壤背景的影响，是进行植被生物量和盖度定量反演的有力工具；建立了荒漠化监测主要评价因子的定量反演模型，并分析了模型的适用性。

The following results are made from this research: Assessing data quality and band combination of different bands in line with geo-target features in desertification areas, and determining basic bands for desertification monitoring. And understanding and studying the spectral features and variation rules of geo-targets in the experimental area, raising that it is the basis of geo-targets information collection with imaging spectrometer data to understand spectral features and variation rules of geo-targets, realizing that in a great extent spectral-integrated-form-based classification method can remove the phenomenon of "different spectrum with same objects" resulted from reflection ratio curve translation because of the angle change among sensor, targets and observation direction, and the average and variance images can be introduced to solve the problem of two kinds of geo-target with similar spectral forms and much different values of whole reflectionratio. It is suggested that "red edge" range bands of vegetation, which has close relationship with vegetation cover and biomass, is the main characteristic bands and important basis for careful vegetation classification and quantitative retrieval, and pixel-based derivative spectral analysis is very useful for removing the effects of soil background values and quantitatively retrieving vegetation biomass and cover. The remote sense quantitative retrieval model is developed for main appraisable factors of desertification monitoring assessment with imaging spectrometer data and then the applicability of model is analyzed.

研究结果如下：首先针对荒漠化地区的地物特征，对高光谱数据不同波段的数据质量、波段组合进行了评价，提出了适用于荒漠化监测的基本波段选择集；初步了解和掌握了研究地区的地物光谱特性及变异规律，进一步明确了掌握地物光谱特征和变异规律是用成像光谱仪数据提取地物信息的基础；发现了基于光谱整体形状的分类方法在很大程度上能够消除由于传感器、地物目标观测方向之间的角度变化引起的反射率曲线整体平移的&同物异谱&现象，对于谱形相似而整体反射率的值相差较大的两类地物，通过引入均值和方差图像参与分类得到解决；研究还表明在植被&红边&范围内的波段是进行荒漠化监测的主要特征波段，这些波段与植被生物量和盖度都有密切的关系，是开展精细植被分类研究和植被定量反演的重要基础；像元的导数光谱分析可以消除土壤背景的影响，是进行植被生物量和盖度定量反演的有力工具；建立了荒漠化监测主要评价因子的定量反演模型，并分析了模型的适用性。

In order to obtain infrared spectral radiance distribution of some infrared sources, such as spectral radiant flux density, spectral radiant intensity, spectral radiance and spectral irradiance, the instrument response function under different conditions must be known.

在应用红外发射光谱来获得某些红外源的绝对光谱能量数据，如辐射源光谱辐射通量密度、辐射源光谱辐射强度、辐射源光谱辐射亮度及光谱辐射照度等时，需要得知不同条件下的仪器响应函数。

The spectral imaging technology, with the resolving power both on the space and on the spectral, is the perfect combination of the image analysis and the spectral analysis.The study on the prismatic element is one of the key technologies in the area of the spectral imaging. The acousto-optic tunable filter is a newfashioned prismatic element.

近年来，光谱成像技术在军事侦察、精细农业、生物医学等领域的广泛应用前景引起了愈来愈多研究者的关注。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。