182 lines
6.4 KiB
Python
182 lines
6.4 KiB
Python
import numpy as np
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import matplotlib.pyplot as plt
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from scipy.interpolate import CubicSpline
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# -----------------------------
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# 1. 从data.txt读取分块格式数据（先wl+n，再wl+k）
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# -----------------------------
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def read_split_data(file_path):
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"""
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解析分块数据格式：
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第一部分：wl n（多行数据）
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第二部分：wl k（多行数据）
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返回：sorted_wl, n, k（波长已排序，保证n和k一一对应）
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"""
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with open(file_path, 'r', encoding='utf-8') as f:
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lines = [line.strip() for line in f if line.strip() and not line.startswith('#')]
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# 分割n数据和k数据（以"wl k"为分界）
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split_idx = None
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for i, line in enumerate(lines):
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if line == 'wl k': # 找到k数据的表头
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split_idx = i
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break
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# 提取n数据（表头后到split_idx前）
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n_lines = lines[1:split_idx] # 跳过"wl n"表头
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wl_n = []
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n_list = []
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for line in n_lines:
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wl, n_val = line.split()
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wl_n.append(float(wl))
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n_list.append(float(n_val))
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# 提取k数据（split_idx后）
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k_lines = lines[split_idx + 1:] # 跳过"wl k"表头
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wl_k = []
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k_list = []
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for line in k_lines:
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wl, k_val = line.split()
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wl_k.append(float(wl))
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k_list.append(float(k_val))
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# 转换为numpy数组
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wl_n = np.array(wl_n)
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n_list = np.array(n_list)
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wl_k = np.array(wl_k)
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k_list = np.array(k_list)
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# 确保n和k的波长完全一致（否则插值会出错）
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assert np.allclose(wl_n, wl_k), "n和k的波长列表不一致！"
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# 排序（按波长递增，避免插值异常）
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sorted_idx = np.argsort(wl_n)
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sorted_wl = wl_n[sorted_idx]
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sorted_n = n_list[sorted_idx]
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sorted_k = k_list[sorted_idx]
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return sorted_wl, sorted_n, sorted_k
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# 读取数据
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wl_all, n_all, k_all = read_split_data('/Users/spasolreisa/IdeaProjects/asiaMath/data.txt')
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# 三次样条插值（覆盖全波段，保证计算精度）
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cs_n = CubicSpline(wl_all, n_all) # 折射率n的插值函数
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cs_k = CubicSpline(wl_all, k_all) # 消光系数k的插值函数
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# 定义待研究的PDMS薄膜厚度（μm），可按需调整
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thicknesses = [0.5, 1.0, 1.5, 2.0]
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# -----------------------------
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# 2. 核心物理模型：薄膜发射率计算
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# -----------------------------
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def fresnel_reflectance(n1, k1, n2, k2):
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"""
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菲涅尔反射率（垂直入射近似，考虑消光系数k）
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输入：介质1的n/k，介质2的n/k
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输出：垂直入射时的反射率R（0-1）
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"""
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m1 = n1 + 1j * k1 # 介质1的复折射率
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m2 = n2 + 1j * k2 # 介质2的复折射率
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return np.abs((m1 - m2) / (m1 + m2)) ** 2
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def thin_film_emissivity(n_film, k_film, d, wl, n_air=1.0, k_air=0.0):
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"""
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薄膜发射率计算（考虑多光束干涉和吸收）
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输入：
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n_film/k_film: 薄膜的折射率/消光系数
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d: 薄膜厚度（μm）
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wl: 波长（μm）
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n_air/k_air: 空气的折射率/消光系数（默认n=1, k=0）
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输出：
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epsilon: 发射率（0-1）
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"""
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# 1. 计算上下表面的菲涅尔反射率
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R12 = fresnel_reflectance(n_air, k_air, n_film, k_film) # 空气→薄膜
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R23 = fresnel_reflectance(n_film, k_film, n_air, k_air) # 薄膜→空气
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# 2. 计算相位差和吸收衰减
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delta = 2 * np.pi * n_film * d / wl # 干涉相位差（无吸收时）
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alpha = 4 * np.pi * k_film * d / wl # 吸收导致的振幅衰减系数
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# 3. 多光束干涉反射率（考虑吸收）
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numerator = R12 + R23 * np.exp(-alpha) + 2 * np.sqrt(R12 * R23 * np.exp(-alpha)) * np.cos(2 * delta)
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denominator = 1 + R12 * R23 * np.exp(-alpha) + 2 * np.sqrt(R12 * R23 * np.exp(-alpha)) * np.cos(2 * delta)
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R_total = numerator / denominator
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# 4. 多光束干涉透射率（考虑吸收）
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T_total = (1 - R12) * (1 - R23) * np.exp(-alpha) / denominator
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# 5. 基尔霍夫定律：ε = 1 - R - T（局部热平衡）
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epsilon = 1 - R_total - T_total
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return epsilon
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# -----------------------------
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# 3. 计算并绘制不同厚度的发射率光谱
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# -----------------------------
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# 定义计算波长范围（覆盖数据的有效波长区间，步长0.01μm保证平滑）
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wl_min = wl_all.min()
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wl_max = wl_all.max()
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wl_fine = np.linspace(wl_min, wl_max, int((wl_max - wl_min) / 0.01) + 1)
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# 创建绘图
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plt.figure(figsize=(12, 7))
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plt.rcParams['font.sans-serif'] = ['Arial'] # 统一字体
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# 存储不同厚度的发射率结果（用于后续分析）
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emission_dict = {}
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for d in thicknesses:
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# 插值得到当前波长下的n和k
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n_film = cs_n(wl_fine)
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k_film = cs_k(wl_fine)
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# 计算发射率
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epsilon = thin_film_emissivity(n_film, k_film, d, wl_fine)
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emission_dict[d] = epsilon
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# 绘制光谱曲线
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plt.plot(wl_fine, epsilon, linewidth=2, label=f'Thickness = {d} μm')
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# -----------------------------
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# 4. 图表美化与标注（突出辐射制冷关键波段）
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# -----------------------------
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# 标注大气透明窗口（8-13μm，辐射制冷核心波段）
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if wl_min <= 13 and wl_max >= 8: # 仅当数据覆盖该波段时才标注
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plt.axvspan(8, 13, alpha=0.15, color='red', label='Atmospheric Window (8-13 μm)')
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# 坐标轴与标题
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plt.xlabel('Wavelength (μm)', fontsize=14)
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plt.ylabel('Emissivity ε(λ)', fontsize=14)
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plt.title('PDMS Thin Film Spectral Emissivity for Different Thicknesses', fontsize=16, fontweight='bold')
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# 网格、图例与范围设置
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plt.grid(True, alpha=0.3, linestyle='--')
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plt.legend(fontsize=12, loc='best')
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plt.ylim(0, 1.05) # 发射率范围0-1.05（留出余量）
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plt.xlim(wl_min, wl_max)
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# 保存图片（高分辨率）
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plt.tight_layout()
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plt.savefig('PDMS_emissivity_spectrum.png', dpi=300, bbox_inches='tight')
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plt.show()
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# -----------------------------
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# 5. 输出关键波段（8-13μm）的平均发射率（若数据覆盖该波段）
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# -----------------------------
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if wl_min <= 13 and wl_max >= 8:
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print("=== 8-13 μm 大气窗口平均发射率 ===")
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wl_window = np.linspace(8, 13, 500) # 大气窗口内的波长点
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for d in thicknesses:
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n_window = cs_n(wl_window)
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k_window = cs_k(wl_window)
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epsilon_window = thin_film_emissivity(n_window, k_window, d, wl_window)
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avg_epsilon = np.mean(epsilon_window)
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print(f"厚度 {d} μm: 平均发射率 = {avg_epsilon:.4f}")
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else:
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print("数据未覆盖8-13μm大气窗口，跳过该波段平均发射率计算。") |