基于KANO模型的后共享时代单车设计决策研究——从设计师与消费者视角

目的 探究消费者对共享单车的需求偏好，获取用户和设计师对产品的认知差距，并提出相应的设计决策，为共享单车以及两轮车行业的产品创新提供启迪与参考。方法 从设计师思维与消费者偏好的视角出发，对共享单车消费者偏好的各项设计原则(属性)进行细致分类，建立8个评价维度与41个评价特征，采用KANO模型对有效回收样本进行定量统计及定性分析。结果 基于前期调研与KANO模型分析，提出后共享时代单车设计的相关策略。结论 在后共享单车时代下，设计师需要根据用户真实的产品偏好与体验感知进行设计策略的研究，以设计出真正满足用户需求和体验期望的产品。同时也证明KANO模型作为一种阐明用户不同感性需求的方法，有助于设计师进行设计决策的综合判断，提升设计的竞争力。     

Research on slope reliability analysis using multi-kernel relevance vector machine and advanced first-order second-moment method

Engineering with Computers - To increase the efficiency and accuracy in slope stability analysis, a reliability analysis method based on machine learning and the advanced first-order second-moment...     

一种改进的特征匹配算法在碎片云测量建模中的应用

为满足超高速撞击典型Whipple防护构型的损伤评估需求,利用图像处理技术对碎片云序列阴影图像进行深入研究。使用超高速序列激光阴影成像仪得到三组不同实验条件下碎片云发展过程的高清阴影图像,分别对每组最具代表性的2帧进行图像处理分析;根据碎片云图像特点以及碎片运动特性,提出了一种改进的碎片二次特征匹配算法,该方法包含碎片粗定位、特征定义及初匹配和精确匹配三步策略;通过运用改进的匹配算法,对选取的相邻两帧图片完成碎片高效匹配,并提取匹配碎片的运动参数,进而分析碎片的速度分布和飞行角度分布,获取二次碎片云相关运动特性;得到三组实验各自的轨迹模拟图。根据得到的轨迹分析结果分别对三组实验的后板损伤进行估计,并通过与防护构型的实际损伤结果进行比较,验证了该方法的有效性。     

等温退火对8030铝合金导线组织性能的影响

研究了不同等温退火工艺对8030铝合金导线组织及性能的影响。结果表明:等温退火前后合金均由α-Al基体和Al₆Fe相组成。在同一等温温度下,随着等温时间的延长组织逐渐趋于均匀化;同一等温时间下,随着等温温度的升高,组织趋于均匀化的时间缩短。经过等温退火处理后铝合金导线的导电率均有所提高,在470 ℃均匀化退火24 h后再经240 ℃等温4 h,合金导电率达到最高值57.21%IACS,比未经热处理试样的导电率提高了2.4%IACS。经过等温退火处理后铝合金导线的硬度及抗拉强度均有所降低,塑性大幅度提高。在470 ℃均匀化退火24 h后再经260 ℃等温8 h,合金的伸长率最高可达23.64%。热处理前后合金均为塑性断裂。     

气动弹片对垂直轴风力机性能影响研究

片对垂直轴风力机气动性能的影响并分析了其流动机理。结果表明：气动弹片在高尖速比下可显著抑制流动分离并改善其动态失速特性，功率系数得到极大提升；切向力和转矩系数在气动弹片作用相位角范围内，均有一定提高，而在其它相位角内，风力机性能不受影响。     

Brief Review of Precipitated Iron-Based Catalysts for Low-Temperature Fischer–Tropsch Synthesis

Topics in Catalysis - Fischer–Tropsch synthesis (FTS) is a promising way to produce clean liquid fuels and high value-added chemicals from low-value carbon-containing resources such as coal,...     

Effect of coupling agent content on properties of composites made from polylactic acid and chrysanthemum waste

Chrysanthemum flower is among one of the highly sought after and widely planted flower crops, in particular for cultural and religious ceremonies. However, the chrysanthemum stem and stalk have little value and usually discard as by‐product waste from floristry. The objective of this research is to investigate the potential value of utilizing chrysanthemum stem and stalk as reinforcing fillers for thermoplastic composites. In this study, 2‐mm thick composite sheet containing predefined formulations of polylactic acid (PLA), chrysanthemum waste filler (CWF) ranging from 15 to 60 phr, and maleated polyethylene (MAPE) coupling agent up to 5 phr were prepared with the aid of Haake internal mixer and compression molding. The effect of MAPE loading on tensile, thermal, and morphological properties of PLA/CWF composites was investigated. The findings revealed that PLA/CWF composite attained improved tensile modulus compared to the neat PLA, and the tensile modulus increases with higher concentration of CWF. However, both tensile strength and elongation at break reduces with increase loading of CWF. Overall, PLA/CWF composites with MAPE shows better performance compared to those without MAPE, where an optimum strength of 21.8 MPa can be achieved with 60 phr CW and 3 phr MAPE. The measured tensile strength is comparable to alternatives natural fiber thermoplastic composites demonstrating its potential to be used in non‐structurally demanding application. J. VINYL ADDIT. TECHNOL., 26:10–16, 2020. © 2019 Society of Plastics Engineers     

New disposable microfluidic chip without evaporation effect for semen analysis in clinics and homes

The number of infertile couples considering using assisted reproductive technologies (ARTs) is growing. Several key indices, such as sperm concentration and motility, are considered when determining an appropriate technique among the existing ARTs. While microscopy is the only way to observe sperms, this method tends to overlook the actual swimming ability of sperms because sperms can be observed only within a very narrow field of view (FOV). In this paper, we propose a microfluidic chip capable of measuring the motility of sperms by inducing the actual swimming ability of sperms in microchannels. To determine whether sperms swim by themselves and reach the target point, 5–10 min is required in an incubator at 37 °C, which inevitably causes the evaporation of the fluid at the microfluidic chip inlet or outlet. A unique structure has been added to the microfluidic chip to prevent unwanted fluid flow due to evaporation, and counting and sorting capabilities of the fabricated device have been experimentally demonstrated. The microfluidic chip is shown to have a good agreement with commercial chips in total sperm counting. Another feature of sorting motile and progressive sperm to 95% on one chip is also verified. This feature differentiates our solution from the existing commercial chips and can help increase the success rate of ARTs. The developed MFC can provide a way to determine the actual swimming motility of sperms using a microscope in small clinics or a portable kit which is publicly available without the expensive sperm analysis equipment.

     

具有外套管的释热元件表面温度求解

为进行具有外套管的释热元件的性能分析，需准确计算元件包壳外侧的温度分布。由于套管结构内外均存在流体，传热情况较为复杂，因此本文基于传热基本方程和能量守恒关系，设计开发了专用的迭代算法和计算程序求解该结构温度分布，并采用典型算例，将计算结果与Fluent软件仿真结果进行对比。结果表明，本文程序计算结果与Fluent软件仿真结果的相对误差小于5%。基于本算法编写的程序模块与燃料元件性能分析程序相耦合，可提高燃料性能分析流程的独立性。