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181.
182.
为了改变水溶液的物理性质, 提高ICP发射光谱的辐射强度, 实验采用波长为976 nm的近红外激光和10.6 μm的CO2激光正交辐照水溶液, 研究了不同激光功率密度和辐照时间对水溶液表面张力和粘度的影响, 也探讨了处理后水溶液对ICP光谱强度的增强作用。实验结果表明, 在976 nm激光功率密度为0.265 7 W·cm-2, CO2激光为0.2069 W·cm-2以及辐照时间为40 min条件下, 水溶液的表面张力和粘度比未进行激光处理时的分别减小了42.13%和14.03%, 而雾化效率升高了51.26%。将优化条件下激光处理的水溶液引入ICP光源后发现, 样品元素As, Cd, Cr, Hg和Pb的光谱强度比水溶液未处理时的分别提高了46.29%, 94.65%, 30.76%, 33.07%和94.58%, 信背比分别增大了43.84%, 85.35%, 28.71%, 34.37%和90.91%;等离子体温度和电子密度也分别升高了5.94%和1.18%。可见, 双光束激光正交辐照水溶液的方法能够明显降低水溶液的表面张力和粘度, 提高ICP光源的辐射强度, 这为顺利检测水样品中痕量重金属元素创造了条件。 相似文献
183.
利用飞秒脉冲激光对氮化镓(GaN)功率器件进行单粒子烧毁效应定量评估技术研究,针对器件结构建立脉冲激光有效能量传输模型,理论计算了激光有效能量与重离子线性能量传输(LET)的等效关系并开展了试验验证.考虑器件材料反射率与吸收系数对激光的影响,针对介质层界面间的激光多次反射进行参数修正,减小有源区有效能量计算误差.选择一款氮化镓高电子迁移率晶体管(GaN HEMT)与一款肖特基势垒二极管(SBD)功率器件作为典型案例,分别开展飞秒脉冲激光正面与背部辐照试验,计算诱发单粒子烧毁的有效能量,并得到不同入射激光波长的烧毁等效LET阈值,对比了模型理论计算值与实际测量值.同时,研究结果对材料参数未知的GaN功率器件,提供了正面与背部辐照模型的激光试验波长选择参考.该工作将为激光定量评估空间用GaN等宽禁带半导体器件的单粒子烧毁效应机理研究及加固设计与验证提供技术支撑. 相似文献
184.
Tunable enhanced spatial shifts of reflective beam on the surface of a twisted bilayer of hBN 下载免费PDF全文
We investigated Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts of a reflective beam on a twisted bilayer of hexagonal boron nitride (hBN), where a left circularly polarized beam was incident on the surface. Our results demonstrate that the twist angle between the two optical axes plays an important role in obtaining large shifts with a high reflectivity. The GH shift with 10λ0 is achieved, while the reflectivity is near 100% by tuning the twist angle. The maximum of the IF shift is found in the certain condition satisfied by the reflective coefficients, and the shift strongly depends on the twist angle between the optical axes of the two slabs. The spatial shifts obtained directly from the GH and IF shift definitions were provided, which indicate that the theoretical results from the stationary phase method are believable. These results may open up a new way for developing the nano-optical devices. 相似文献
185.
High-sensitivity Bloch surface wave sensor with Fano resonance in grating-coupled multilayer structures 下载免费PDF全文
A new type of device consisting of a lithium niobate film coupled with a distributed Bragg reflector (DBR) was theoretically proposed to explore and release Bloch surface waves for applications in sensing and detection. The film and grating made of lithium niobate (LiNbO3) were placed on both sides of the DBR and a concentrated electromagnetic field was formed at the film layer. By adjusting the spatial incidence angle of the incident light, two detection and analysis modes were obtained, including surface diffraction detection and guided Bloch detection. Surface diffraction detection was used to detect the gas molecule concentrations, while guided Bloch detection was applied for the concentration detection of biomolecule-modulated biological solutions. According to the drift of the Fano curve, the average sensor sensitivities from the analysis of the two modes were 1560 °/RIU and 1161 °/RIU, and the maximum detection sensitivity reached 2320 °/RIU and 2200 °/RIU, respectively. This study revealed the potential application of LiNbO3 as a tunable material when combined with DBR to construct a new type of biosensor, which offered broad application prospects in Bloch surface wave biosensors. 相似文献
186.
187.
免疫质谱法检测肝癌血清多肽标志物 总被引:1,自引:0,他引:1
建立免疫亲和富集分离与质谱分析相结合的免疫质谱法用于血清多肽标志物pep5的检测。多克隆抗体与蛋白A琼脂糖颗粒偶联用于捕获pep5,基质辅助激光解析电离飞行时间质谱检测标志物。本方法的线性范围为1~48 nmol/L,检出限0.2 nmol/L;回收率为93.0%~103.1%,相对标准偏差(RSD)为6.4%~11.8%;反复冻融3次pep5,检测结果稳定;检测临床肝癌/正常血清样本灵敏度为78.0%、特异度为90%。该方法方便、快速、准确,适用于临床样本中低浓度标志物的检测研究,对于癌症的早期诊断具有重要意义。 相似文献
188.
High temperature thermoelectric properties of highly c-axis oriented Bi2Sr2Co2Oy thin films fabricated by pulsed laser deposition 下载免费PDF全文
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co20v thin films prepared by pulsed laser deposition on LaA1Oa (001). Both the electric resistivity p and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m. cm and 202 V/K at 980 K, resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples. A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature. The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application has high temperature thin film thermoelectric devices, 相似文献
189.
High temperature thermoelectric properties of highly c-axis oriented Bi<sub>2</sub>Sr<sub>2</sub>Co<sub>2</sub>O<sub>y</sub> thin films fabricated by pulsed laser deposition 下载免费PDF全文
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co2Oy thin films prepared by pulsed laser deposition on LaAlO3(001).Both the electric resistivity ρ and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m·Ω· cm and 202 μV/K at 980 K,resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples.A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature.The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application in high temperature thin film thermoelectric devices. 相似文献
190.