圆与多边形重叠区域的判定算法

本文提出了一种实用的圆与多边形重叠区域的判定算法，它集判断与确定功能于一体。该算法将多边形的边视为有向线段，通过引入多边形顶点的入边，出边交点的概念，研究了圆与多边形重叠区域的确定问题，并给出了作出其重叠区域的定理。     

Bresenham画圆算法的改进

由于没有充分考虑圆弧的特点，使得传统的BreSenham画圆算法效率还不够高，算法过于复杂，容易造成失真。该文总结了传统的BreSenham画圆算法，指出了传统Bresenham画圆算法的缺陷，提出改进的BreSenham画圆算法，并用实例进行验证，对Bresenham画圆算法的优越性进行了分析。     

砌体结构房屋底层墙体开洞时洞口最大宽度计算的探讨

本文根据国家现行规范和结构构件承载能力极限状态分析．提出了砌体结构房屋底层墙体开洞宽度的计算方法，供工程技术人员在工程实践中参考。     

关于在湖北组建三个城市经济圈的构想

城市经济圈的形成和崛起 ,明显起着拉动区域经济发展作用。分析了在湖北省组建 3个城市经济圈的缘由 ,阐述了各个城市经济圈的空间范围 ,提出了政府在城市经济圈组建中应采取的对策措施     

消费空间生产视角下杭州市美丽乡村发展特征——以下满觉陇、龙井、龙坞为例

在新型城镇化背景下,传统乡村的更新升级日益与大都市消费空间扩张、农业现代化紧密联系在一起。以杭州为例,其外围乡村地域已经形成动力机制各异的不同消费空间圈层模式,研究选取3个典型美丽乡村为案例分析对象,构建美丽指数对其现状特征进行评价,并探索各自不同的动力机制。结论是,3个乡村均具有生产与消费兼具的地域空间特征,在人居环境、社会文化、产业经济方面具有一定的差异性,这是由于受不同的动力主体推动所致,由此也形成了都市化背景下乡村空间的圈层模式。     

低压大功率同步发电机的环流分析

分析了低压大功率同步发电机定子绕组中环流产生的主要原因,在产品设计中采取相应的措施,降低了环流,通过测试验证发电机的温升值满足技术要求.     

Packing equal circles into a circle with circular prohibited areas

The paper considers the problem of packing a maximal number of identical circles of a given radius into a multiconnected domain. The domain is a circle with prohibited areas to be finite unions of circles of given radii. We construct a mathematical model of the problem and investigate its characteristics. The starting points are constructed in a random way or on the ground of the hexagonal lattice. To find the local maxima, a modification of the Zoutendijk method of feasible directions and a strategy of active inequalities are applied. We compare our results with the benchmark instances of packing circles into circular and annular containers. A number of numerical examples are given.     

A simple and sensitive aptasensor with rolling circle amplification for viable Cronobacter sakazakii detection in powdered infant formula

Cronobacter sakazakii is a foodborne, emerging opportunistic pathogen that causes severe bacteremia, necrotizing enterocolitis, and sepsis with a mortality rate of up to 80%. In this study, we developed a simple and sensitive fluorescent turn-off aptasensor with rolling circle amplification assay for viable C. sakazakii detection in powdered infant formula. The results showed that the proposed aptasensor has good performance and specificity for detecting viable C. sakazakii in pure culture and powdered infant formula samples within 3 h. Under the optimal reaction conditions, there is a linear relationship between fluorescent intensity at 490 nm and logarithmic concentration of C. sakazakii in the range of 2.7 × 10⁵ to 2.7 × 10² cfu/mL, with a limit of detection of 2.7 × 10² cfu/mL in pure culture. The proposed aptasensor achieved a recovery of 104 to 111% in pure culture, and 96 to 107% in spiked powdered infant formula samples. The proposed aptasensor does not require complicated DNA extraction steps or antibodies, and can be performed at 37°C, making it a convenient and sensitive strategy for C. sakazakii detection.     

Hand gesture recognition using valley circle feature and Hu’s moments technique for robot movement control

Hand gesture recognition is a simpler and more natural way of human computer interaction. The goal of this paper is to detect the continuous gestures and use them to convey information for the robot movement control. So the hand gesture recognition requires fast and extremely robust. In this paper, three strategies were used to realize the hand gesture recognition: (1) the valley circle (VC) was created for the first stage of 6 fingertip numbers classification; (2) the hybrid feature vector of Hu’s moments, convexity and compactness (HCC) were constructed for the second stage of gesture recognition of the remainder unknown gesture classes; (3) a new template matching recognition (NTMR) algorithm was proposed to realize 10 gesture classes recognition. To test the hand gesture recognition method, the robot movement control system was built. It is experimental proved that the NTMR algorithm is effective and corrective for the hand gesture recognition. It increased the recognition accuracy by 4% and decreased the recognition duration by 112 ms compared with Hu’s moment method. It had good performances of the real-time hand gesture acquisition and information conveyance, and it had the invariant properties when the gesture was rotated and shifted and scaled.     

水泵转子径向圆跳动检测数据修正

针对应用千分表和电涡流传感器进行水泵转子径向圆跳动检测时,检测结果出现正弦变化规律的现象,分析了安装偏心误差对检测结果的影响原理,建立了相应的数学模型.运用最小二乘拟合法计算出变化曲线的幅值及初相位,从而消除偏心误差实现误差分离.结果表明,当将所提方法应用在水泵转子径向圆跳动检测的工程实践中时,可以有效消除安装偏心引起的误差,从而提高检测精确度.拟合平方和误差约为0. 000 9,所提方法可以广泛应用于轴类工件的检测实践.