Nucleus操作系统内存池模块移植的研究与应用

基于对Nucleus操作系统内核的研究与分析,在三星ARM1176JZF芯片S3C6410上将Nucleus内存池模块移植并合理应用。根据TD-LTE无线综合测试仪中的设计要求,介绍了Nucleus内存池的静态分配和动态分配方式,并根据不同应用环境采用对应的内存池分配优化措施,在实现操作系统基本内存管理功能的同时,满足了TD-LTE无线综合测试仪对系统内存资源分配和调度时间的设计要求。     

基于混沌麻雀搜索算法的无人机航迹规划方法

针对无人机(UAV)航迹规划求解计算量大、难收敛等问题,提出了一种基于混沌麻雀搜索算法(CSSA)的航迹规划方法.首先,建立二维任务空间模型与航迹代价模型,将航迹规划问题转化为多维函数优化问题;其次,采用立方映射初始化种群,并使用反向学习策略(OBL)引入精英粒子,增强种群多样性,扩大搜索区域范围;然后,引入正弦余弦算...     

基于三坐标测量机的机器人位姿精度检测方法

针对医疗场合导航引导下的手术机器人定位精度检测问题,提出了基于三坐标测量机的机器人位姿距离精度测量方法。该方法通过放置在一个平面上的三个标准球来实现三坐标测量机对姿态精度的测量,并参照机器人辅助外科手术系统的定位原理构建基于三坐标测量机的机器人位姿检测平台。在此基础上,依据国家标准规定的机器人性能检测方法和过程,完成机器人位姿距离精度的测量。通过该方法对研发的骨科手术定位机器人进行测量的结果表明,所设计机器人位置距离准确度和重复性分别在[10-1]mm和[10-2]mm级别,姿态距离准确度和重复性分别在[10-1]度和[10-2]度级别。最后将该机器人应用于前交叉韧带重建手术实验,结果表明通过这种方法检测的机器人能够满足手术场合要求。     

高密度CO2处理过程中虾肌球蛋白分子间作用力的变化

高密度CO2（dense phase carbon dioxide,DPCD）是一种非常有前景的非热食品加工技术,能诱导蛋白 质发生变性并进行自组装形成凝胶。为了探讨DPCD诱导蛋白质自组装形成凝胶的机制,以凡纳滨对虾肌球蛋 白为对象,研究DPCD处理压力和温度对肌球蛋白分子间作用力的影响。结果表明：与未处理的相比,DPCD处 理能使肌球蛋白的氢键和离子键贡献降低（P＜0.05）,而使疏水相互作用、二硫键和非二硫共价键的贡献增加 （P＜0.05）;在相同DPCD处理温度下,压强（5～25 MPa）对肌球蛋白分子间作用力无显著影响（P＞0.05）;在 相同DPCD处理压强下,随着温度（40～60 ℃）升高,氢键和二硫键贡献无显著变化（P＞0.05）,非二硫共价键 贡献呈增加趋势（P＜0.05）,疏水相互作用呈降低趋势（P＜0.05）,离子键贡献则先降低后升高（P＜0.05）。因 此,疏水相互作用、二硫键和非二硫共价键是DPCD诱导肌球蛋白形成凝胶过程中的主要分子间作用力,而氢键和 离子键不是其主要分子间作用力。研究结果为阐明DPCD诱导蛋白质形成凝胶的机制提供了基础数据。     

Influence of Dicyclopentadiene Co-Polymers on the Hardening Processes and Properties of Portland Cement Composites

Dicyclopentadine (DCPD) polymers can be used for the manufacture of self healing materials due to their ability to form in the presence of a catalyst a highly cross-linked polycyclopendiene. The DCPD polymers selected for this work contain also another constituent sequence (maleic anhydride), therefore in this paper we assess also the possibility to use it for a potential self healing process. In this paper is presented the influence of two types of (DCPD) co-polymers based on maleic anhydride copolymers on the hardening processes and main properties of portland cement pastes and mortars, as a first step in the development of a self-healing cementitious composite. The properties (mechanical strengths and volume variations) of the cementitious composites with DCPD co-polymers are influenced by the chemical structure of the obtained compounds and curing medium (dry or humid air). The mortars with AM (maleic anhydride/dicyclopentadiene co-polymer) did not develop any mechanical strength due to an important swelling phenomenon determined by the hydrolysis of anhydride groups and sterical modifications in chain structures. The presence of APA (AM copolymer modified with p-amino phenyl acetic acid) decreases the compressive strengths but has a less important effect on the flexural strength. The APA polymer-cement interaction consists in a chelatization process involving the nitrogen atoms and hydrogen bonding of carboxyl groups providing, in this case, a good cohesion of the composite material. For both polymers a delay in cement hydration was noticed at early ages as well as the formation of organo-mineral phases.     

S-Allyl cysteine in garlic (Allium sativum): Formation,biofunction, and resistance to food processing for value-added product development

S-allyl cysteine (SAC), which is the most abundant bioactive compound in black garlic (BG; Allium sativum), has been shown to have antioxidant, anti-apoptotic, anti-inflammatory, anti-obesity, cardioprotective, neuroprotective, and hepatoprotective activities. Sulfur compounds are the most distinctive bioactive elements in garlic. Previous studies have provided evidence that the concentration of SAC in fresh garlic is in the range of 19.0–1736.3 μg/g. Meanwhile, for processed garlic, such as frozen and thawed garlic, pickled garlic, fermented garlic extract, and BG, the SAC content increased to up to 8021.2 μg/g. BG is an SAC-containing product, with heat treatment being used in nearly all methods of BG production. Therefore, strategies to increase the SAC level in garlic are of great interest; however, further knowledge is required about the effect of processing factors and mechanistic changes. This review explains the formation of SAC in garlic, introduces its biological effects, and summarizes the recent advances in processing methods that can affect SAC levels in garlic, including heat treatment, enzymatic treatment, freezing, fermentation, ultrasonic treatment, and high hydrostatic pressure. Thus, the aim of this review was to summarize the outcomes of treatment aimed at maintaining or increasing SAC levels in BG. Therefore, publications from scientific databases in this field of study were examined. The effects of processing methods on SAC compounds were evaluated on the basis of the SAC content. This review provides information on the processing approaches that can assist food manufacturers in the development of value-added garlic products.     

微孔几何轮廓对浮环气膜密封动压润滑特性的影响

目的 充分研究微织构几何轮廓对浮环气膜密封润滑特性的影响,调节微尺度流动,提高密封综合性能,为气膜浮环密封的优化设计提供理论基础。方法 基于气膜润滑理论,建立表面织构化浮环密封的润滑模型,以圆形、正方形、椭圆形、三角形4种轮廓微织构孔为研究对象,采用有限差分法对流体动压控制方程进行数值求解,获得密封间隙内气膜压力分布,通过试验验证理论模型的正确性和有效性,并考察不同几何轮廓的微织构孔对浮环密封性能的影响规律。结果 微织构孔均可产生显著的流体动压效应,具有三角形轮廓特征的微织构孔在综合密封性能上表现出最佳效果,其次是椭圆形、正方形,最后是圆形。在相同工况条件下,不同几何轮廓的微织构孔对密封性能参数的影响具有相似的规律。其中,转速、压力和偏心率的增大均可提高气膜浮升力;随着压力和偏心率的增加,泄漏率迅速升高,随着转速的升高而缓慢下降;气体摩擦力随着转速、压力和偏心率的升高而升高。结论 在轴套表面合理设计微纹理,并对不同几何轮廓微孔所适应的工况参数进行了研究,明确了不同工况下织构类型的选择和优化。研究结果可为浮环气膜密封的轴套加工制造提供理论依据,具有实际应用价值。     

IGBT模块材料选型的仿真研究

作为电力电子变换器的核心器件,IGBT功率模块的可靠性是目前学术界和工业界关注的重点。本文借助有限元分析软件,根据IGBT模块的实际结构,构建了IGBT模块的电-热-力仿真模型。针对目前IGBT模块键合线失效的难题,研究了不同键合线材料与表面金属化层材料的选型对模块温度云图及应力云图的影响。仿真结果表明键合线材料的选型与模块内部的温度分布具有较强的相关性,金属化层材料的选型与模块内部的应力分布具有较强的相关性。因此,通过合理选择模块表面金属化层与键合线材料类型能极大程度降低模块内部的温度和应力,进而降低键合线失效的风险,提高模块的可靠性。     

Influence of microfibrillated cellulose and soft biocomponent on the morphology and thermal properties of thermoplastic polyurethanes

Composite materials from thermoplastic polyurethanes (TPUs) with biodegradable segments and microfibrillated cellulose (MFC) were developed as alternatives to traditional materials used in packaging or biomedical applications. Two TPUs were synthesized by the prepolymer method starting from different soft segments, poly(ε-caprolactone)/poly(butylene adipate) (PUBA) or poly(ε-caprolactone)/poly(ethylene oxide) (PUEO), and isophorone diisocyanate/aliphatic chain extender. Proton nuclear magnetic resonance (¹H NMR) confirmed the structure and Fourier transform infrared spectroscopy (FTIR) along with scanning electron microscopy showed that the soft segments with different hydrophobicity led to a higher phase mixing in PUBA and improved microphase separation in PUEO. MFC was added in the TPUs with different soft segments to increase biocompatibility, strength, and degradation rate. A better thermal stability, a gradual increase of crystallinity and a better dispersion of MFC were noticed in PUEO composites compared to PUBA ones. The crystallinity increased with 78% and 50% in PUBA and PUEO composites with 5 wt% MFC compared to the neat polyurethanes showing the nucleating ability of MFC. In addition, the enhanced storage modulus, with 75% and 25% in PUEO and PUBA composites, highlighted the reinforcing efficiency of MFC. Therefore, the addition of MFC to the already synthesized TPUs allows tailoring the morphology and thermal properties of TPUs for industrial application.