矢量偏振光束产生新方法

为了解决现有矢量偏振光束(VPB)产生装置结构复杂、成本高等问题,提出了利用一种由多个线型偏振器件构成的同心圆环装置即显偏器(PAF)产生矢量偏振光束的新方法。基于显偏器的特殊结构特点,由LED光源输出的自然光束经显偏器,可产生角向偏振光束(APB),再经两个快轴成45°角的半波片可将角向偏振光束转换成径向偏振光束(RPB)。采用此方法获得的矢量偏振光束经线偏振片验证其光强分布情况,研究发现所得结果与已发表的实验结果相符,验证了该方法的有效性和实用性。     

水下电磁场源的二维DOA和极化估计

以电磁矢量传感器在均匀海水中的电声测量为运用背景,建立了水中单个电磁矢量传感器的数据接收模型,采用特征值分解的信号子空间TLS-ESPRIT算法,对基于该算法的单个电磁矢量传感器估计多个信号源的DOA和极化参数问题进行了研究。     

多轴三维织机斜纱引导机构特殊步进电机设计

引入斜纱来增强三维机织物的平面属性是避免其各向异性突出缺陷的一种有效措施。简要介绍了织造多轴三维织物必须的斜纱引导机构,在UG中对该机构进行建模,在Ansoft Maxwell中建立单个直线电机二维模型,并对此电机进行静态磁场分析及推力仿真,为多轴三维织机虚拟样机建模、设计与仿真,以及其物理样机的研制奠定了必要基础。     

短链脂肪酸-酰化淀粉对小鼠抑郁样行为的缓解及机制

大量研究证实“微生物-肠-脑轴”在抑郁症的发生发展中发挥重要作用,而肠道微生物产生的短链脂肪酸(short chain fatty acids,SCFAs),更是参与神经调控作用的关键分子。该研究首次采用SCFA-酰化淀粉在大肠定点释放5类短链脂肪酸,探究其对慢性应激诱导的抑郁症状的缓解及机制。以雄性C57BL/6 J小鼠为研究对象,通过为期5周的慢性不可预知温和应激构建抑郁小鼠模型,通过旷场实验、高架十字迷宫实验和强迫游泳实验对小鼠的抑郁样行为进行评价。同时对小鼠应激激素、神经递质水平及相关酶的表达水平进行检测。结果显示,乙酸、异丁酸和丁酸能在不同程度上减轻小鼠抑郁样行为,其可能机制与SCFAs修复下丘脑-垂体-肾上腺轴反馈调节障碍、恢复5-羟色胺的正常代谢相关。该研究为抑郁症的营养干预提供了新的理论依据。     

Study on solids translational and rotational motions in rotating cans

Study on translational and rotational motion of solids is important in a wide range of engineering processes. However, rotational motion of solid particles in an opaque system has not been given much attention due to the lack of appropriate measurement methods. This paper presents a new technique, Multiple-Positron Emission Particle Tracking (Multiple-PEPT), to track both rotational and translational motions of a solid simultaneously. The sample study presented here is to track the rotation and translation of a cubed potato in a food can for optimising the canned food process. The results have demonstrated that the rotational and transitional motion of the cubed potato can be simultaneously tracked through mounting three small (200 microns) radioactive tracers on the cube corners. The rotation and translation of the cube can be reconstructed based on the trajectories of the three tracers. The translational and rotational motions of the potato particle are related to each other, and both the motions are greatly dependent on the solids fraction, the liquid viscosity and the density difference between the solid and liquid; but follow specific patterns.     

多轴三维织机斜纱引入机构的设计

为了避免三维机织物各向异性突出的缺陷,通过引入斜纱来增强三维机织物的平面属性,以适应航空航天等应用领域对三维机织物各向同性的性能要求。介绍了多轴三维织物的组织结构,设计其织造用的斜纱引导机构,该机构由4个特殊直线步进电机组成;在UG中对该机构进行建模并在Ansoft Maxwell中建立单个直线电机二维模型,并对此电机进行静态磁场分析以及推力仿真。为多轴三维织机虚拟样机的建模、设计与仿真及其物理样机的研制奠定必要的基础。     

旋转图像的合成与识别仿真

介绍了对旋转图像进行计算机模拟识别的两种方法:匹配相关和联合相关.通过对两种算法模拟数据的比较,得出了联合相关算法对待识别图像方面的优越性,以及计算机模拟识别相对于光学器件的简洁性和显著性.     

Some results on the algebraic immunity of Boolean functions

From the motivation of algebraic attacks on stream and block ciphers,the concept of algebraic immunity(AI) of a Boolean function was introduced and studied extensively.High algebraic immunity is a necessary condition for resisting algebraic attacks.In this paper,we give some lower bounds on the algebraic immunity of Boolean functions.The results are applied to give lower bounds on the AI of symmetric Boolean functions and rotation symmetric Boolean functions.Some balanced rotation symmetric Boolean functions with their AI near the maximum possible value「n/2」are constructed.     

石化装置离心式压缩机反转的分析及对策

对于离心式压缩机紧急停车时转子是否反转,本文利用S8000技术从三个方面进行了分析,提出了转子紧急停车时转向的判断方法;分析了紧急停车时反转产生的原因以及危害,提出了防止反转的对策;对压缩机的选型提出了建议。