Subjects: Digital Publishing >> New Media submitted time 2023-10-08 Cooperative journals: 《中国传媒科技》
Abstract：【目的】探究自媒体短视频内容升级的可行性策略，以期达到提高短视频的播放量和增强自媒体竞争力的效果。【方法】通过市场调研和统计分析，现阶段自媒体短视频的主要类型有新闻资讯类、娱乐搞笑类、生活记录类等。【结果】调查和分析结果表明，虽然自媒体短视频类型多样，但是在内容上存在同质化问题，进行自媒体短视频内容升级存在必要性和紧迫性。【结论】在此基础上，文章分别从打造优质自媒体团队、提高短视频制作水平、推行“短视频+电商”和“短视频+文旅”等跨界合作模式等方面，总结了短视频内容升级的具体方法，保证了自媒体能够稳定输出优质作品。
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-19 Cooperative journals: 《金属学报》
Abstract： To solve such problems as sensitivity to noise and low accuracy of grain size evaluation using traditional ultrasonic time-domain attenuation method, an ultrasonic nondestructive evaluation model based on multiscale attenuation coefficient was proposed. The distribution of time- scale of ultrasonic energy was obtained by means of wavelet transformation, then to calculate the distribution of attenuation coefficient with scale, and to make a comprehensive analysis of attenuation characteristics of various scales. After the weighted multi-scale ultrasonic attenuation coefficient was defined, a multi-scale ultrasonic attenuation evaluation model was established on the basis of combination of optimal dimension and normalized weight distribution strategy designed by particle swarm optimization. 304 stainless steel was used in the test. The distribution of attenuation coefficient with scale shows that ultrasonic wave of small scales attenuates fast, presenting the frequency characteristics of ultrasonic attenuation among high scattering materials. Following increase of the sample grain size, ultrasonic attenuation of all scales was intensified significantly. Test results show that the sound velocity method, the traditional evaluation method and the proposed method have maximum systematic errors of +12.57%, +5.85% and -1.33%, respectively. With these 3 methods, evaluation results of the sample with a mean grain size of 103.5 mm measured by metallographic method are (110.4�7.8), (98.2�6.6) and (101.7�3.9) mm, respectively, showing that the presented method can not only reduce the systemic error, but also can effectively control the random error by constant Q filtering properties of wavelet transformation. This model can be extended to grain size evaluation of other metals.
Subjects: Biology >> Botany >> Applied botany submitted time 2020-09-15 Cooperative journals: 《广西植物》
Abstract：兰科（Orchidaceae）植物是植物界中最进化、种类最丰富的类群之一，有较高的环境要求和较强的生态系统依存性，加上很多兰科植物具有较高的观赏价值和药用价值，各地采挖频繁，受威胁十分严重，已成为保护植物中的“旗舰”类群。本文基于文献资料和近年来课题组野外调查数据，分析贵州省野生兰科植物的地理分布状况、就地保护现状与保护空缺，以期为该地区野生兰科植物科学合理的保护管理提供参考。结果表明：（1）贵州省野生兰科植物共“累计筛选法”共鉴别出保护贡献率较高的前
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-11-07 Cooperative journals: 《工程热物理学报》
Abstract：提出了一种太阳能热化学与化学回热过程联合的冷热电联产系统。利用太阳能驱动甲醇分解反应，产生的合成气在内燃机中燃烧作功，内燃机排烟余热与导热油换热，并驱动甲醇分解反应加以回收余热。对系统进行了热力学性能分析，探究了全年典型日下系统热力性能与储能特性规律。研究结果表明:设计工况下系统一次能源利用率为78.4%，太阳能净发电效率为21.1%。在3001000 W/m'的直射辐照强度范围内，系统可以实现稳定运行，太阳能净发电效率稳定在19.3%21.5%的变化范围内。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-03-22 Cooperative journals: 《工程热物理学报》
Abstract：受加工精度限制，叶片加工外形与设计外形存在一定偏差，该类偏差具有较强的随机性，对叶片气动性能造成不确定性影响。加工叶片外形偏差的不确定性影响为几何尺度上的小扰动问题。本文首先基于伴随方法建立了适用于加工叶片外形偏差气动灵敏度分析及气动性能偏差预估模型。之后，计算某二维涡轮叶片的气动参数伴随灵敏度，由此确定厚度均匀变化的测试叶片的气动性能偏差，并与数值模拟结果进行对比，验证伴随方法在叶片气动不确定性灵敏度分析中的精确性和有效性。最后，采用基于灵敏度分析的Monte Carlo方法研究满足正态分布的批量加工叶片的气动性能偏差，确定了相应的气动偏差统计模型。
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