太赫兹可调谐滤波器设计

为了实现太赫兹信号的可调谐滤波，设计了一种基于柔性材料的太赫兹可调谐滤波器。通过扭曲特氟龙（Teflon）波导形成环型谐振器，实现了160～200 GHz频段的带阻滤波功能。改变谐振腔长可实现自由频谱范围（FSR）和滤波频点的调谐，实验测试了自由频谱范围在1.9 GHz和2.8 GHz间切换以及相应的滤波特性。研究表明，谐振腔长一定时，改变弯曲半径可实现滤波阻带抑制度的调节，柔性材料太赫兹环型谐振器可用于可调谐滤波，且具有较高的自由度。     

谐振变换器的ZVS软开关同步整流技术研究

以感应电能传输(IPT)谐振变换器为研究对象,研究了谐振变换器的ZVS同步整流(SR)技术。分析了基于SR技术IPT谐振变换器的工作原理,利用系统的谐振工作特性,提出了一种新颖的ZVS软开关SR实现方法。建立了系统频闪映射稳态数学模型,给出了ZVS软开关SR的周期不动点函数、数值求解状态变量及ZVS软开关SR工作周期的算法流程。在设计控制电路的基础上,通过实验验证了提出的同步整流技术的可行性。     

一种轻小型四极杆质谱仪射频电源的研制

四极杆结构是四极杆质谱仪的核心结构，由射频电源分别施加两组高压高频信号进行驱动，利用电场的变化和输入离子的质荷比差异对离子进行筛选。针对四极杆质谱仪小型化的研制需求，以信号调制模块、放大模块、反馈电路和直流模块为基本构型，设计了一种应用于轻小型四极杆质谱仪的射频驱动电源。经实际测试，该电源可以在谐振频率1.33 MHz、扫描频率10 Hz的输入条件下，输出峰 峰值电压最高可达3.33 kV的调幅射频高压信号并驱动四极杆结构，扫描切换时间不高于1 ms。射频电源输出信号稳定、波动小、交直比的波动为0.1%。该射频电源相较于常规的四极杆射频电源具有更高的扫描范围，体积小巧，功耗仅30 W，接口简单，有较高的实用价值。     

Restraint Method for Overcoming Heating Irregularity and Improving Heating Equipment Efficiency for Beverage Cans Using High‐Frequency Induction Heating

We were able to reduce heating irregularities in equipment for heating beverage cans by using the high‐frequency induction heating method and determining the resulting improvement in the heating efficiency. The heating irregularity between the top and bottom of the can was reduced to less than 3°C by improving the arrangement of the heating coils for the beverage can by thinning the winding and changing the circuit configuration. The efficiency of power conversion was improved from 93.0% to 97.4%. In this paper, the configuration of the equipment and the experimental results are reported.     

Fundamental Evaluation of Power Supply and Rectifiers for Wireless Power Transfer Using Magnetic Resonant Coupling

This paper provides a fundamental analysis of a power supply and rectifiers for wireless power transfer using magnetic resonant coupling (MRC). MRC enables efficient wireless power transfer over middle‐range transfer distances. MRC for wireless power transfer should operate at a high frequency in the industry science medical band, such as 13.56 MHz, because the size of the transfer device decreases at higher transfer frequencies. Therefore, the output frequency of the power supply on the transmitting side should be 13.56 MHz. In addition, the rectifier on the receiving side is operated at a high frequency. This paper focuses on the reflected power in the power supply and rectifiers. Thus, the parametric design method is clarified for the power supply, including a low‐pass filter to match the output, the impedance of the power supply with the characteristic impedance of the transmission line. In addition, the effects on the rectifiers of silicon carbide and gallium nitride diodes are confirmed by performing an experiment and a loss analysis.     

Fatigue life assessment of a low pressure steam turbine blade during transient resonant conditions using a probabilistic approach

This paper presents a sequential approach used in fatigue life prediction of a low pressure steam turbine blade during resonance conditions encountered during a turbine start-up by incorporating probabilistic principles. Material fatigue properties are determined through experimental testing of used blade material X22CrMoV12-1 along with statistical modelling using regression analysis to interpret the stress-life diagram. A finite element model of a free-standing LP blade is developed using the principle of sub-structuring which enables the vibration characteristics and transient stress response of the blade to be determined for variations in blade damping. Random curve fitting routines are performed on the fatigue and FEM stress data to ensure that the selection of the random variables used in fatigue life calculations is stochastic in nature. The random vectors are selected from a multivariate normal distribution. The use of confidence intervals in the probabilistic fatigue life model works effectively in being able to account for uncertainty in the material fatigue strength parameters and varying stress in the blade root. The predicted fatigue life of the blade is shown to be in good agreement with discrete life modelling results.     

A new design strategy for DC/DC LLC resonant converter: Concept,modeling, and fabrication

In this paper, a new design procedure for LLC converter has been introduced. In fact, this method is a computer-based design algorithm based on a numerical technique. In the process of designing, the value of the resonant element is obtained by solving the LLC converter fundamental equation. This converter will be controlled by using state feedback, such as output voltage variable. As a matter of fact, in a control system, the change of output voltage (because of load variation) will affect the switching frequency, so the output voltage will be tuned. In the designing process, the fundamental equations of LLC converter are obtained, and the value of the resonant elements is calculated. Also, a comparison analysis is carried out between the proposed and typical methods. The simulation is done to investigate the validity of the proposed method. Moreover, a prototype is manufactured, and the experimental test is done to evaluate its applicability.     

南海钙质砂的动剪切模量与阻尼比试验研究

岩土体的动剪切模量和阻尼比是土工建筑物、近海场地动力稳定性分析中的主要动力学参数,为评价南海钙质砂的动力学特性,利用美国GCTS共振柱测试系统,对取自南海地区的钙质砂进行共振柱试验,研究固结压力、相对密实度对其动剪切模量和阻尼比的影响,并与石英砂进行对比分析。研究发现:相同的试验条件下,钙质砂的最大动剪切模量、阻尼比均大于石英砂;从总体而言,钙质砂的动剪切模量在剪应变小于0.1%时大于石英砂动剪切模量,在大于0.1%时两者趋于一致,其动剪切模量比G/Gmax随剪应变γ衰减的速度快于石英砂。根据试验结果建立钙质砂动剪切模量比G/Gmax、阻尼比D的数学模型,并结合现有的钙质砂动剪切模量比及阻尼比研究成果,给出钙质砂动剪切模量比和阻尼比的变化范围,为钙质砂场地工程建设中建筑物动力稳定性分析提供依据。