前、后路手术治疗颈脊髓损伤的效果比较

目的比较前、后路手术治疗颈脊髓损伤的临床效果。方法选取78例颈脊髓损伤患者,抽签随机分为两组,其中39例采用前路手术治疗患者记为前路术组,另外39例采用后路手术治疗记为后路术组,观察两组手术相关指标并结合术后有效随访比较治疗综合效果。结果前路术组手术时间(75.4±10.2)min、术中出血量(206.3±31.5)m L较后路术组明显较低,术后1年颈椎功能JOA评分(14.4±1.8)分较后路术组显著较高(P0.05);前路术组不良结果发生率5.13%较后路术组低(P0.05)。结论同后路手术相比,前路手术具有手术时间短、术中出血量少的特点,且能有效减少术后不良结果的发生,对病情康复和改善预后具有重要意义。     

Control of gain and thermal carrier loss profiles for mode optimization in 980-nm broad-area vertical-cavity surface-emitting lasers

Optical gain and thermal carrier loss distributions regarding current diffusion and various electric contact areas are investigated to improve the near-field modes from the ring-shape to a Gaussian-like configuration for extra-broad-area and oxide-confined vertical-cavity surface-emitting lasers. In this work an equivalent circuit network model is used. The resistance of the continuously-graded distributed Bragg reflectors （DBRs）, the current diffusion and the temperature effect due to different electric-contact areas are calculated and analyzed at first, as these parameters affect one another and are the key factors in determining the gain and thermal carrier loss. Finally, the gain and thermal carrier loss distributions are calculated and discussed.     

Modeling of resistance characteristics of a continuously-graded distributed Bragg reflector in a 980-nm vertical-cavity surface-emitting laser

The resistance characteristics of a continuously-graded distributed Bragg reflector(DBR) in a 980-nm verticalcavity surface-emitting laser(VCSEL) are modeled in detail.The junction resistances between the layers of both the p-and n-DBR mirrors are analysed by combining the thermionic emission model and the finite difference method.In the meantime,the intrinsic resistance of the DBR material system is calculated to make a comparison with the junction resistance.The minimal values of series resistances of the graded p-and n-type DBR mirrors and the lateral temperature-dependent resistance variation are calculated and discussed.The result indicates the potential to optimize the design of the DBR reflectors of the 980-nm VCSELs.