“通信原理”实验课程的改进与探索

通信原理课程的实验教学环节是课程的重要组成部分,合理改进和设计实验课程,是加深学生对课程的理解和提高学生能力的必要手段。本文就当前通信原理实验课程存在的问题和改进方法进行探讨分析,并在教学中加以运用,取得了较好的效果。     

面向区域新业态的地方高校金属材料工程专业改造升级路径研究

本文从适应地方新业态的金属材料工程专业改造和升级路径出发,探索对接产业需求的人才培养模式,形成与信息技术深度融合兼有学科交叉特点的课程体系,探索具有新工科特色的专业人才培养质量评价体系,以期实现地方应用型高校传统工科专业的改造升级和跨越式发展。     

Regulating surface wrinkles using light

Regulating existing micro and nano wrinkle structures into desired configurations is urgently necessary yet remains challenging, especially modulating wrinkle direction and location on demand. In this work, we propose a novel light-controlled strategy for surface wrinkles, which can dynamically and precisely regulate all basic characteristics of wrinkles, including wavelength, amplitude, direction and location (λ, A, θ and L_c), and arbitrarily tune wrinkle topographies in two dimensions (2D). By considering the bidirectional Poisson''s effect and soft boundary conditions, a modified theoretical model depicting the relation between stress distributions and the basic characteristics was developed to reveal the mechanical mechanism of the regulation strategy. Furthermore, the resulting 2D ordered wrinkles can be used as a dynamic optical grating and a smart template to reversibly regulate the morphology of various functional materials. This study will pave the way for wrinkle regulation and guide fabrication technology for functional wrinkled surfaces.     

Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool

Chang’E-4 landed in the South Pole-Aitken (SPA) basin, providing a unique chance to probe the composition of the lunar interior. Its landing site is located on ejecta strips in Von Kármán crater that possibly originate from the neighboring Finsen crater. A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In situ spectra of the regolith have peak band positions at 1 and 2 μm, similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper, which confirms that the regolith''s composition of the landing area is mostly similar to that of Finsen ejecta. The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. The rock may consist of 38.1 ± 5.4% low-Ca pyroxene, 13.9 ± 5.1% olivine and 48.0 ± 3.1% plagioclase, referred to as olivine-norite. The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle, but representative of the lunar lower crust. Alternatively, the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials. This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool, indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model [Icarus 2012; 220: 730–43].     

SAW-driven droplet jetting technology in microfluidic: A review

The introduction of surface acoustic wave (SAW) technology on microfluidics has shown its powerfully controlling and actuating fluid and particle capability in a micro-nano scale, such as fluid mixing, fluid translation, microfluidic pumping, microfluidic rotational motor, microfluidic atomization, particle or cell concentration, droplet or cell sorting, reorientation of nano-objects, focusing and separation of particles, and droplet jetting. The SAW-driven droplet jetting technology enjoys the advantages of simple structure to fabricate with little hindrance, compact size to integrate with other components, high biocompatibility with biological cells or other molecule samples, large force in realizing fast fluidic actuation, and contact-free manipulation with fluid. The realization of this technology can effectively overcome some bottleneck problems in the current micro-injection technology, such as mechanical swear, complicated and bulky structure, and strict limitation of requirements on fluidic characteristics. This article reviews and reorganizes SAW-microfluidic jetting technology from decades of years, referring to the interaction mechanism theory of SAW and fluid, experimental methods of SAW-microfluidic jetting, effects of related parameters on objected pinch-off droplets, and applications of individual structures. Finally, we made a summary of the research results of the current literature and look forward and appraise where this discipline of SAW-microfluidic jetting could go in the future.     

On theory and methods for advanced detonation-driven hypervelocity shock tunnels

This study describes theory and methods for developing detonation-driven shock tunnels in hypervelocity test facilities. The primary concept and equations for high-enthalpy shock tunnels are presented first to demonstrate the unique advantage of shock tubes for aerodynamic ground-based testing. Then, the difficulties in simulating flight conditions in hypervelocity shock tunnels are identified, and discussed in detail to address critical issues underlying these difficulties. Theory and methods for developing detonation drivers are proposed, and relevant progress that has advanced the state of the art in large-scale hypersonic test facilities is presented with experimental verifications. Finally, tailored conditions for detonation-driven shock tunnels are described, laying a solid foundation to achieve long test duration. This interface-matching key issue encountered in developing shock tunnels has been investigated for decades, but not solved for detonation drivers in engineering applications.     

Genomic consequences of population decline in critically endangered pangolins and their demographic histories

Pangolins are among the most critically endangered animals due to heavy poaching and worldwide trafficking. However, their demographic histories and the genomic consequences of their recent population declines remain unknown. We generated high-quality de novo reference genomes for critically endangered Malayan (Manis javanica, MJ) and Chinese (M. pentadactyla, MP) pangolins and re-sequencing population genomic data from 74 MJs and 23 MPs. We recovered the population identities of illegally traded pangolins and previously unrecognized genetic populations that should be protected as evolutionarily distinct conservation units. Demographic reconstruction suggested environmental changes have resulted in a population size fluctuation of pangolins. Additionally, recent population size declines due to human activities have resulted in an increase in inbreeding and genetic load. Deleterious mutations were enriched in genes related to cancer/diseases and cholesterol homeostasis, which may have increased their susceptibility to diseases and decreased their survival potential to adapt to environmental changes and high-cholesterol diets. This comprehensive study provides not only high-quality pangolin reference genomes, but also valuable information concerning the driving factors of long-term population size fluctuations and the genomic impact of recent population size declines due to human activities, which is essential for pangolin conservation management and global action planning.     

论高等学校"双语教学"的师资队伍建设问题

通过对双语教学师资的特殊素质要求进行分析,提出了集专业理论素养、外语综合应用能力、先进教学理念与方法以及和谐的科学人文精神为一体的综合性师资素质构件;进而提出了包括外语教师专业化、正规培养基地、外部引进以及跨地共享合作等途径的多维性建设思路。