Monolithic homogeneous integrated miniaturized triboelectric nanogenerator with an inner air cavity for energy harvesting

Science China Technological Sciences - To realize the high-efficiency acquisition of environmental mechanical energy, traditional triboelectric nanogenerators (TENGs) based on contact-separation...     

A triboelectric/electromagnetic hybrid generator for efficient wind energy collection and power supply for electronic devices

Harvesting energy from ambient environment has been considered as a promising strategy for driving portable electronic devices in a sustainable way. A wind driven triboelectric-electromagnetic hybrid nanogenerator has been fabricated to convert wind energy into electricity. It is composed of an electromagnetic generator(EMG) and a triboelectric nanogenerator(TENG) with the output power of 35 and 0.32 mW, respectively when the wind speed is 5 m/s. Generally, TENG shows a low current output with a high voltage output characteristic, on the contrary the EMG shows a high current output and a low voltage output. This hybrid nanogenerator overcomes these problems and exhibits comprehensive and efficient performance on scavenging energy.Moreover, in view of the output performance and charging ability of the hybrid nanogenerator, it shows high stability, making it suitable for charging capacitors or batteries and driving portable electronics sustainably. A new structure of integrated TENG and EMG was designed to harvest wind energy, which shows potential applications in portable and small device power supply system, especially in the areas of remote mountains, deserts, islands, etc., as emergency power supply.     

Coil-levitated hybrid generator for mechanical energy harvesting and wireless temperature and vibration monitoring

The development of wireless monitoring is currently restricted by the short lifetime of batteries,requiring frequent replacement.Utilization of abundant mechani...     

A numerical study of rock burst development and strain energy release

We consider rock burst to be a dynamic disaster similar to earthquakes, rapid land sliding, or coal mine gas dynamic disasters. Multi-scale mechanical principles imply the same mechanism of damage evolution proceeds the catastrophe. Damage may occur at various scales from a meso-scopic scale to a macroscopic, or engineering scale. Rock burst is a catastrophe at the scale of the engineering structure, such as a tunnel cross section or the work face of a long wall mine. It results from dynamic fracture of the structure where microscopic damage nucleates, expands, and finally propagates into a macroscopic sized fracture band. Rock burst must, therefore, undergo a relatively long development, or gestation, time before its final appearance. In this paper, a study of rock burst within a deeply buried tunnel by numerical methods is described. The results show that during rock burst gestation the distributed microscopic damage in the rock surrounding the tunnel localizes, intersects, and then evolves into a set of concentrated “V” shaped damage bands. These concentrated damage bands propagate in the direction of maximum shear as shearing slide bands take shape. Rock burst happens within the wedge separated by the shear bands from the native tunnel rock. An analysis of the wedge fracture shows that the unloading effects result in rock burst and rapid release of the strain energy. The implications for rock burst prediction in tunnels are that: (1) rock burst develops in the upper arch corners of in the tunnel cross section prior to developing in other zones, so good attention must be paid there; (2) all monitoring, prevention, and treatment of rock burst should be done during the gestation phase; (3) the shear bands contain abundant information concerning the physics and mechanics of the process and they are the foundation of physical and mechanical monitoring of acoustic emission, micro seismic events, stress, and the like. Thus a special study of the shearing mechanism is required.     

基于LabVIEW平台的虚拟正弦信号发生器的设计

虚拟仪器(Virtual Instrument,简称VI)是现代计算机软件技术、通信技术和测量技术相结合的产物.论述虚拟仪器的组成原理、主要功能、特点及应用,同时详细介绍基于LabVIEW虚拟仪器开发平台及设计虚拟正弦信号发生器的方法.     

A novel tuned heave plate system for heave motion suppression and energy harvesting on semi-submersible platforms

Deepwater offshore structures such as semi-submersible platforms suffer powerful ocean waves due to their location and site condition. The long distance away from the shore also brings many difficulties to energy supply for the platform operation. How to reduce the response of the platform and convert the wave energy into electrical power is a meaningful topic. In this paper, a tuned heave plate system (THP) is presented and designed to be employed on a semi-submersible platform for heave motion suppression and energy harvesting. This THP system is composed of spring supports, a power take-off system (PTO), and a heave plate. The PTO system is a permanent magnet linear generator (PMLG), which could directly convert the kinetic energy of the heave plate into electronic power. The stiffness of the spring supports is designed based on the principle of the tuned mass damper (TMD). The numerical model of the platform and the THP system is established according to the hydrodynamic analysis results of the platform. The model is tested and modified by scale model tests on the platform in the wave tank. A parameter study, including the size, tuned period, and damping ratio of the THP system, is conducted systematically based on the numerical model. The optimal parameters of the THP are selected due to the maximum heave motion reduction under severe wave conditions in South China Sea. The performance of the semi-submersible with and without the THP system under different wave conditions is analyzed. It is demonstrated that this novel tuned heave plate system could reduce the heave motion of the semi-submersible platform significantly and generate considerable power, which makes the THP system have a broad prospect for development.     

一种山楂采摘机的机构设计及其运动方程建立

为实现机械式采摘山楂,设计了一种五自由度的山楂采摘机构.首先设计出山楂采摘机构简图,然后利用D-H参数表示法对机构简图建立相应的运动学方程,最后通过Matlab软件拟合出相应图形验证了方程的正确性.     

一种北斗二号测距码生成器的设计

针对北斗二号卫星导航系统中普通测距码的生成问题,提出了一种改进的测距码生成的实现原理,并给出具体实现方案。与传统的测距码生成器相比,本设计采用不同卫星编码设置不同初值的方法,提高了电路使用的便利性,还在算法上采用并行处理的方法,提高了码生成速率。对电路功能的仿真证明其可以得到与传统码生成器相同的编码结果。     

民间艺术与现代包装设计融合的思考

民间艺术融入现代包装设计有着积极的理论和现实意义.在分析民间艺术在包装设计中应用现状的基础上,提出了民间艺术与现代包装设计融合的路径,并提出了图形、造型、色彩、材质等方面的民间艺术在现代包装设计中的创新体现.     

变速恒频双馈风力发电系统的速度模式控制

基于变速恒频双馈风力发电系统能实现最大风能追踪,首先建立了双馈感应发电机的三阶数学模型,在基于定子磁链定向的转子励磁控制策略基础上,提出在最大风能追踪的过程中,采用速度模式控制的系统动态特性优于采用电流模式控制的动态特性,并给出了状态空间解释.最后给出了仿真波形,仿真结果验证了分析的正确性.     

一类带导数的数值积分公式

介绍一类带导数的数值积分公式，给出这类求积公式的推导过程、误差估计以及收敛性证明．利用这类求积公式在被积函数的导数容易计算，尤其是在积分区间的端点上的导数值容易计算，并且在不增加计算量或者少增加计算量的前提下达到提高计算精度的目的．计算实践证明，这类数值积分公式在一定条件下是行之有效的．     

1 000 MW发电机变压器组保护容错设计和配置

1000MW发电机组电压等级高、容量大,其继电保护受到非常多的关注．提出大机组保护的配置方案以及可能面临的问题,分析保护的容错原理和技术,介绍失磁保护、定子接地保护及转子接地保护的选型要求,认为保护装置硬件系统的冗余度是确保1000MW机组安全经济运行的重要措施．     

基于塑性应变能的钢支撑疲劳损伤评估方法

在罕遇地震下,框架-中心支撑结构中的钢支撑常因局部屈曲位置的低周疲劳开裂而过早退出工作.在焊接工字形钢支撑低周疲劳试验研究基础上,提出了一种可用于框架-中心支撑体系非线性动力时程分析中钢支撑疲劳损伤评估的经验方法,并给出了相关步骤的算法流程.研究结果表明:以钢支撑滞回环塑性应变能为损伤参量,能实时估算在随机位移荷载下钢支撑的低周疲劳累积损伤发展,并与试验结果吻合较好.     

双层立面系统与公共建筑节能设计

从节能建筑设计的要求出发，分析了双层立面系统的构成与基本类型，阐述了它在建筑结构和建筑功能等方面的科学性，指出结合当地环境与气候特点的双层立面系统对我国公共建筑的节能设计具有现实意义。     

用FPGA实现GPS的C/A码发生器

采用了FPGA方法来模拟高动态(Global Position System GPS)信号源中的C/A码产生器.C/A码在GPS中实现分址、卫星信号粗捕和精码(P码)引导捕获起着重要的作用,根据文献[1]引入C/A码生成方程,通过硬件描述语言VERILOG在ISE中实现电路生成,采用MODELSIM、SYNPLIFY工具分别进行仿真和综合.最后由图3展示的结果与文献[1]相对比证明了设计的正确性.     

解冻冷源温差发电模拟实验装置的设计与开发

针对冷冻产品化冻过程中所产生的冷能回收利用问题,开发了一款基于温差发电的解冻水冷能回收利用装置,完成了测量显示系统、温差发电系统和解冻水模拟系统的组建,并以之为平台进行了实验研究。实验结果表明:利用解冻水可以实现温差发电,提供了一种新能源发电系统,具有一定的应用前景,但未解决温差发电片自身导热造成的两端温差较小的问题,实际应用中可以考虑利用风进行热端的能量交换。     

风电场设计中机组选型与布置分析

风电场设计工作中,风电机组的型式选择和布置直接影响到风电场的投资效益.针对的风电机组的选型和布置,分析了风力发电机组选型和风电场选址工作过程中应当注意的问题.基于胶南子罗风电场设计工程实例,在综合考虑风场地形、风机类型特点、造价等多方面因素的基础上,利用软件实现了机组选型和布置的优化设计.该设计方法有利于提高风能利用效率和风电场经济效益.     

Mach-Zehnder干涉仪差分检测布里渊温度和应变同时传感系统

分析了基于自发布里渊散射的温度和应变分布同时测量原理,针对已报导的外差检测和直接检测系统中存在的问题,提出了一种基于单通光纤Mach-Zehnder干涉仪(MZI)的双端差分检测布里渊温度和应变同时传感系统,通过理论分析证明了系统的可行性。该系统具有成本低,实现简单,可消除光源频率不稳定性干扰等特点,在分布式光纤温度和应变同时测量中具有广阔的应用前景。     

天然气制乙炔与燃料电池的集成系统

基于天然气部分氧化法制乙炔的产物中含有约54%的H2,提出了一个天然气制乙炔与燃料电池的集成系统。新系统采用天然气生产乙炔副产合成气,合成气经水气转化提高H2含量,H2经燃料电池高效转化,以及余热锅炉系统回收燃料电池的余热和排气。利用Aspen Plus模拟结果表明:基于584.3 kg.h-1进料的天然气,在POC反应温度1 773 K,吸收压力1.013 MPa,解析压力0.103 MPa的条件下,系统生产乙炔1.9 MW,向外输出电1.7 MW,系统净发电效率为26.8%,火用效率为43.4%。研究表明,新系统提高了乙炔生产的能量转换率。