LT-GaAs飞秒光电导之电场响应特性

利用飞秒光电导自相关技术研究了LT GaAs飞秒光电导开关时间随外加偏置电场的变化规律 .实验结果显示当外加偏置电场从0.5×10⁴ V/cm 上升到9.5×10⁴ V/cm 时，光电导 开关时间开始在200fs附近缓慢变化再迅速增加到750fs.这是由于随着外加电场增加，Fren kel-Poole效应导致的EL2缺陷中心库仑吸引势垒降低和电场增强的碰撞电离效应显著增强 ，导致载流子俘获截面减小，载流子寿命增加之故. 关键词： 光电导自相关技术 载流子俘获时间 Frenkel-Poole效应 电子碰撞电离效应     

Generation of unconventional geometric phase gates in ion trap-optical cavity system by squeezed operators

Based on squeezed operators this paper has implemented an ideal unconventional geometric quantum gate (GQG) in ion trap-optical cavity system by radiating the trapped ions with the cavity field of frequency w_c and an external laser field of frequency w_L. It can ensure that the gate time is shorter than the coherence time for qubits and the decay time of the optical cavity by appropriately tuning the ionic transition frequency w₀, the frequencies of the cavity mode w_c and the vibrational mode ν. It has also realized the unconventional GQG under the influence of the cavity decay based on the squeezed-like operators and found that the present scheme works well for the smaller cavity decay by investigating the corresponding fidelity and success probability.     

Raman spectral analysis of renal tissue: a novel application

Renal cell carcinoma (RCC) accounts for 85% of all primary renal cancers. The definitive diagnosis of RCC relies exclusively on the subjective pathological interpretation of the surgical specimen. In this study, we aimed to analyze renal tissue using objective Raman spectroscopy (RS). We obtained 15 pairs of RCC (T) and corresponding normal renal parenchymal tissues (N) from our biobank. There are three subtypes of RCC: clear cell RCC (ccRCC), papillary RCC (pRCC), and chromophobe RCC (cRCC). Five pairs of tissue of each subtype were enrolled. Fresh‐frozen sliced tissues were used for the RS detection. The Raman spectra between T and N were compared and analyzed using partial least squares (PLS) regression. Data for a total of 55 T and 58 N analyzable RS samples were obtained. The spectra were normalized by dividing the intensity of the characteristic peak at 1003 cm⁻¹ using phenylalanine's Raman peak. After further analysis with PLS, the sensitivity and specificity for discriminating T from N were 95% and 93%, respectively. The RCC subtypes can be discriminated at an accuracy of 72% for ccRCC, 88% for cRCC, and 86% for pRCC. This study demonstrates the feasibility of analyzing renal tissue using RS. RS, with its advantages of easy and objective tissue assessment, may be applied to aid intraoperative decision making and pathological tissue assessment. Copyright © 2014 John Wiley & Sons, Ltd.