激光熔覆陶瓷涂层技术研究

阐述了激光熔覆的相关理论,对熔覆材料及激光功率参数进行了设计,从激光熔覆陶瓷涂层在工业上的应用,展望了激光熔覆陶瓷技术的应用前景。     

Strengths and Weaknesses of Non-enhanced and Contrast-enhanced Cadaver Computed Tomography Scans in the Teaching of Gross Anatomy in an Integrated Curriculum

Cadaver-specific postmortem computed tomography (PMCT) has become an integral part in anatomy teaching at several universities. Recently, the feasibility of contrast-enhanced (CE)-PMCT has been demonstrated. The purpose of this study was to identify particular strengths and weaknesses of both non-enhanced and contrast-enhanced PMCT compared to conventional cadaver dissection. First, the students’ perception of the learning effectiveness of the three different modalities have been assessed using a 34-item survey (five-point Likert scale) covering all anatomy course modules. Results were compared using the nonparametric Friedman Test. Second, the most frequent artifacts in cadaver CT scans, were systematically analyzed in 122 PMCT and 31 CE-PMCT data sets to quantify method-related limitations and characteristics. Perfusion quality was assessed in 57 vascular segments (38 arterial and 19 venous). The survey was answered by n = 257/320 (80.3%) students. Increased learning benefits of PMCT/ CE-PMCT compared to cadaver dissection were found in osteology (2/3 categories, P < 0.001), head and neck (2/5 categories, P < 0.01), and brain anatomy (3/3 categories, P < 0.01). Contrast-enhanced-PMCT was perceived particularly useful in learning vascular anatomy (10/10 categories, P < 0.01). Cadaver dissection received significantly higher scores compared to PMCT and CE-PMCT in all categories of the abdomen and thorax (7/7 categories, P < 0.001), as well as the majority of muscular anatomy (5/6 categories, P < 0.001). Frequent postmortem artifacts (total n = 28, native-phase n = 21, contrast injection-related n = 7) were identified and assessed. The results of this work contribute to the understanding of the value of integrating cadaver-specific PMCT in anatomy teaching.     

碱金属气室参数测试教学实验平台搭建北大核心

碱金属气室是原子磁强计、原子陀螺仪、原子钟等量子传感器的核心敏感元件,其内部的碱金属原子蒸汽通过与激光、磁场等相互作用,实现对物理量的高精度测量。实验室搭建了针对一类高温、高压碱金属气室的参数测试教学实验平台,该平台通过测量激光吸收光谱,获得气室内部缓冲气体的压强以及碱金属原子蒸汽的原子数密度。该平台使学生能够直接观察到激光与原子的相互作用,有助于学生加深对碱金属气室的理解以及培养学生的实验动手能力,同时也为研究生和本科生的相关课程提供了有力支撑。