基于Petri网的应急管理工作流模型

讨论了由Petri网发展起来的工作流网WF-net的定义、工作流执行结构及任务触发方法,引入WF-net建立应急管理信息系统工作流模型,提出了一种基于Petri网工作流模型的建模方法及其相关规则．以一个省级应急管理系统为例,详细阐述了构建Petri网工作流模型的过程,并利用验证工具对该模型进行了正确合理性分析．     

北京西郊浅层地下水回灌的水质预测

地下水回灌不仅能够弥补地下水资源的亏空,而且能够稀释净化受污染的地下水。根据北京水源四厂的回灌试验数据,利用PHREEQC模拟软件进行了水质混合模拟和水质预测研究。回灌试验对南井水质影响较大,北井和东井的水质基本没有变化;南井的水质由Ⅲ类水质提升为Ⅱ类水质,其氯化物、硫酸盐、硝酸盐和碳酸氢盐浓度在回灌结束时与回灌井的浓度非常接近;而钾、钙和镁的最终浓度略微低于回灌井中相应指标的浓度,可能是由于阳离子交换作用导致。混合模拟水质与其回灌实测水质数据具有很好的相关性,由此获得南井的模拟混合比与回灌时间的线性方程,其R2高达0.999。据此预测北井在相同的回灌条件下需要回灌11d,其水质才能由最初Ⅳ类水质提升为Ⅱ类水质。本研究的水质预测方法能够有效提高地下水回灌的效率,对于地下水的精准回灌具有重要的指导意义。     

Complementary Electromagnetic‐Triboelectric Active Sensor for Detecting Multiple Mechanical Triggering

With the fast development of integrated circuit technology and internet of things, sensors with multifunctional characteristics are desperately needed. This work presents an integrated electromagnetic‐triboelectric active sensor (ETAS) for simultaneous detection of multiple mechanical triggering signals. The good combination of a contact‐separation mode triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) realizes the complement of their individual advantages. The theoretical calculation and analysis of EMG and TENG are performed to understand the relationship between their output and the external mechanical signals. The experimental results show that the output voltage of TENG part is suitable to detect the magnitude of the external triggering force with a sensitivity of about 2.01 V N^?1. Meanwhile, the output current of EMG part is more appropriate to reflect the triggering velocity and the sensitivity is about 4.3 mA (m s^?1)^?1. Moreover, both the TENG part and the EMG part exhibit good stabilities after more than 20 000 cycles of force loading and unloading. One ETAS that can record the typing behavior of the finger precisely is demonstrated. In addition, the TENG part can harvest the mechanical energy during typing for possible powering of tiny electronics. This ETAS has promising applications in complex human–machine interface, personal identification, and security system.     

大型风力机的噪声源产生机制实验研究

近年来,风力发电在国内得到了快速发展,但大型风力机产生的噪声也引起了广泛关注。该文通过远场传声器测量法开展了大型风力机噪声实验,研究了风力机的主要噪声源位置及产生机制。结果表明,在风力机的来流风的下游方向、风力机风轮叶片平面方向的噪声较大,存在声压级峰值的纯音基频和倍频,表明风力机的主要噪声源是叶片尖端气动噪声和风轮后面的机械噪声。最后指出了对这些主要噪声源进行有效控制的一些措施。     

One-dimensional ordinary–slow extraordinary–Bernstein mode conversion in the electron cyclotron range of frequencies

The ordinary–slow extraordinary–Bernstein(O-SX-B) mode conversion in the electron cyclotron range of frequencies(ECRF) is revisited in slab geometry. The analytical formula of the O-SX conversion efficiency by Mj?lhus is upgraded to include the magnetic field gradient, and the analytical expression of the SX-B conversion efficiency by Ram and Schultz is generalized for the case of oblique injection. Therefore, the conversion efficiency and optimal parallel refractive index for the whole O-SX-B conversion are obtained analytically and a shift of optimal parallel refractive index due to SX-FX loss is found. Full wave calculations are also presented to be compared with the analytical results.     

Effect of melt flow on morphology and linear thermal expansion of injection‐molded ethylene–propylene–diene terpolymer/isotactic polypropylene blends

An ethylene–propylene–diene terpolymer/isotactic polypropylene blend with a structure of co‐continuous microlayers was fabricated by injection molding and was then investigated. The blend exhibited an extremely low coefficient of linear thermal expansion (CLTE) in the directions of the length and the width. As the thickness of the oriented portion increased, the CLTE was further reduced. The morphology of the co‐continuous microlayers and the thermal expansion behavior varied with the sampling positions on the injection‐molded sheets. To study the relationship between the morphology and the melt flow, the melt flow behavior during injection molding was simulated using Moldflow. Orientation of the microlayers was determined using shear flow. When the shear rate increased, the orientation state increased and the CLTE decreased. © 2015 Society of Chemical Industry     

铜纤维长度对ABS/铜纤维复合材料导电性能的影响

研究了在(丙烯腈/丁二烯/苯乙烯)共聚物(ABS)/铜纤维复合材料混炼加工过程中基体粘度、剪切速率和铜纤维的原始长度对混炼后铜纤维长度的影响,并讨论了混炼后的铜纤维长度对复合材料导电性能的影响.结果表明,高剪切速率对铜纤维长度的破坏作用远远大于低基体粘度对铜纤维长度的保护作用.较长铜纤维在混炼过程中缠绕在一起不易分散均匀.研究发现,选用合适的加工工艺,原始长度较短的铜纤维在混炼后仍然可以保持一定的长度,并且由此制得的复合材料导电性能优于由原始长度较长的铜纤维制得的复合材料.     

复杂切割类零件的快速建模技术与实现

探讨复杂切割类零件的结构特点、特征分类,指出复杂切割类零件建模的关键问题,提出双斜要素在建模时的定位方法,适用于具有特征造型功能的三维设计CAD平台中的切割类零件的三维建模。     

Effect of organoclays on the morphology and thermal expansion of PA6/SEBS alloy

The effect of organoclay on phase morphology development of PA6/SEBS alloys had been investigated. PA6/SEBS blends of various compositions, with and without the presence of exfoliated organoclay in the PA6 phase, were prepared and the morphology and thermal expansion of these blends were examined. The results suggested that at compositions where PA6 remains as the matrix domain, the presence of the organoclay had little or no effect upon the blends morphology, PA6/SEBS alloy with SEBS as the matrix could evolve from sea‐island to cocontinuous structure after 5 phr organoclay were added. Significant reduction in the coefficient of linear thermal expansion (CLTE) along theflow direction and furthermore improving the heat distortion temperature of the injection‐molded PA6/SEBS/organoclay ternary nanocomposites was observed due to the formation of a total stable and fine cocontinuous nanolayer structure. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

考虑偏好连接摩擦系数的产品设备模型及优化

制造业发展使数据量不断增加,设备数量不断增加,随之而来的是如何从这些数据中挖掘出有用的信息,对企业的资源进行配置,这对于企业的效率提高有重要的作用。文章把企业产品设备网络作为一个系统进行研究,从复杂网络的角度进行了研究。以BA模型为基础,根据企业产品设备的实际情况,指出了网络连接中存在摩擦因素μ,提出了一个企业产品设备演化模型,并围绕度分布、邻域节点平均度、社区结构等展开研究。可以对企业在资源利用,资源配置方面有重大的指导作用,可以给国家在制造业方面的信息化建设和有效利用资源提供一个指导。