lick concat

在MySQL中，CONCAT函数用于将多个字符串拼接在一起。以下是使用CONCAT函数的示例：

SELECT CONCAT('字符串', 字段名) AS 别名 FROM 表名;
SELECT CONCAT('博客时间: ', blogTime) AS 新时间 FROM t_blog;

这些语句将在查询结果中将指定的字符串与字段值拼接在一起，并使用别名来表示拼接后的结果。

相关问题

matllab计算天文光谱25个lick线指数的代码

以下是一个计算天文光谱25个Lick线指数的MATLAB代码，其中包括了一些常见的Lick线指数，你也可以根据需要添加其他指数：

% 读入光谱数据
data = load('spec.txt');
wavelength = data(:,1); % 波长
flux = data(:,2); % 通量

% Lick线指数的中心波长
center_wavelength = [4000, 4100, 4300, 4500, 4600, 4700, 4800, 4900, ...
    5100, 5200, 5300, 5400, 5500, 5600, 5700, 5800, 5900, 6000, ...
    6100, 6300, 6400, 6500, 6600, 6700, 6800];

% Lick线指数的带宽
bandwidth = [155, 40, 120, 80, 50, 90, 60, 45, 110, 35, 45, 80, ...
    60, 70, 80, 80, 100, 100, 80, 150, 100, 100, 50, 50, 50];

% 计算Lick线指数
lick_indices = zeros(1, 25);
for i = 1:25
    lambda_center = center_wavelength(i);
    lambda_blue = lambda_center - bandwidth(i)/2;
    lambda_red = lambda_center + bandwidth(i)/2;
    idx = find(wavelength >= lambda_blue & wavelength <= lambda_red);
    if ~isempty(idx)
        flux_mean = mean(flux(idx));
        lick_indices(i) = -2.5*log10(flux_mean);
    end
end

% 输出结果
fprintf('Lick线指数:\n');
fprintf('Hdelta_A: %.3f\n', lick_indices(1));
fprintf('Hgamma_A: %.3f\n', lick_indices(2));
fprintf('Hdelta_F: %.3f\n', lick_indices(3));
fprintf('Fe4383: %.3f\n', lick_indices(4));
fprintf('Ca4455: %.3f\n', lick_indices(5));
fprintf('Fe4531: %.3f\n', lick_indices(6));
fprintf('C4668: %.3f\n', lick_indices(7));
fprintf('Hbeta_A: %.3f\n', lick_indices(8));
fprintf('Fe5015: %.3f\n', lick_indices(9));
fprintf('Mg1: %.3f\n', lick_indices(10));
fprintf('Mg2: %.3f\n', lick_indices(11));
fprintf('Mgb: %.3f\n', lick_indices(12));
fprintf('Fe5270: %.3f\n', lick_indices(13));
fprintf('Fe5335: %.3f\n', lick_indices(14));
fprintf('Fe5406: %.3f\n', lick_indices(15));
fprintf('Fe5709: %.3f\n', lick_indices(16));
fprintf('Fe5782: %.3f\n', lick_indices(17));
fprintf('NaD: %.3f\n', lick_indices(18));
fprintf('TiO1: %.3f\n', lick_indices(19));
fprintf('TiO2: %.3f\n', lick_indices(20));
fprintf('CaII: %.3f\n', lick_indices(21));
fprintf('CaII2: %.3f\n', lick_indices(22));
fprintf('G4300: %.3f\n', lick_indices(23));
fprintf('Hgamma_F: %.3f\n', lick_indices(24));
fprintf('Fe3: %.3f\n', lick_indices(25));

请注意，此代码假设你的光谱数据保存在一个名为`spec.txt`的文本文件中，第一列是波长，第二列是通量。你需要将其替换为你自己的数据文件名和格式。此外，此代码假设你的光谱数据已经经过了一些基本的预处理，例如背景减除、波长校准等。如果你的数据需要其他处理，请在此代码之前添加相应的代码。

matllab计算天文光谱25维lick线指数的代码

这是一个使用MATLAB计算天文光谱Lick线指标的示例代码：

% Lick index definition
% Lick indices are defined as a ratio of the flux in a bandpass centered on a 
% feature to the flux in a nearby pseudo-continuum bandpass. The feature is 
% defined with two passbands of equal width, one centered on the feature and 
% one to the blue of the feature. The pseudo-continuum bandpasses are defined 
% to be at the same position relative to the feature bandpasses in all Lick 
% indices. Here we use the definitions from Worthey et al. 1994.

% Load the Lick index bandpass definitions
load LickIndex.mat

% Load the spectrum data
load spectrum.mat

% Smooth the spectrum with a Gaussian filter
sigma = 2;
spectrum_smooth = imgaussfilt(spectrum, sigma);

% Compute the Lick indices
n = size(spectrum_smooth, 2);
lick_index = zeros(n, 25);
for i = 1:25
    feature = spectrum_smooth(:, LickIndex(i).feature);
    continuum = (spectrum_smooth(:, LickIndex(i).blue) + ...
        spectrum_smooth(:, LickIndex(i).red)) / 2;
    lick_index(:, i) = sum(feature, 2) / sum(continuum, 2);
end

% Plot the Lick indices
figure;
plot(lick_index);
xlabel('Wavelength (Angstroms)');
ylabel('Lick index');
title('Lick indices for spectrum');
legend(LickIndex.label);

这里假设spectrum.mat中包含了一个N x M的矩阵，其中N是波长采样点数，M是光谱数量。你需要替换这个矩阵为你自己的数据。LickIndex.mat包含了25个Lick线指标的定义，每个定义包含了feature、blue、red、label四个字段。