Highly sensitive ultraviolet detector using a ZnO/Si layered SAW oscillator

This study elucidates a highly sensitive ultraviolet light detector using the combination of an oscillator circuit with a high-frequency amplifier, a matching network and a layered surface acoustic wave (SAW) device. In this structure, a ZnO thin film is simultaneously used as an active layer for UV detection and a piezoelectric layer for exciting a high-order surface acoustic wave. The microstructure and crystallization of ZnO films were investigated using the scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The SAW oscillator shows a good performance with output power of − 1.14 dBm and phase noise of −94.7 dBc at 100 kHz. Firstly, the frequency shifts of the oscillator exhibit rapid increase with the intensity of the UV light. Then the increased shifts decayed at certain UV intensity due to the saturated photogenerated carriers. An extreme frequency shift of 1017 kHz was obtained as the UV intensity reached 551 μW/cm². The maximum sensitivity of 8.12 ppm/(μW/cm²) can be obtained in this detector.     

A measurement system for YTO

Yttrium iron garnet（YIG） tuned oscillator （YTO）,which is widely used in signal source,is difficult to be measured manually for its numerous parameters.In order to accomplish the measurement of YTO quickly and automatically,this paper gives the design of an auto-measurement system based on genernal purpose interface bus （GPIB）.     

Helmholtz共振腔的设计及其脉动流体强化换热效果的试验分析

采用试验的方法分析了流体力学不稳定性对强化换热的影响。试验中，水流经Helmholtz共振腔被转变为脉动流体，脉动的水流经单管换热器被加热，试验测量了不同条件下加装共振腔和不加共振腔时的换热系数，结果发现加装Helmholtz共振腔后换热管的换热系数可以提高10％～40％。     

Testing of Oscillators

To guarantee correct functioning of oscillators the amplifier gain and the series resistance of the resonator constituting this module have to be tested. A method is proposed whereby the oscillator configuration remains as in application.     

Optimization and design of a novel prescaler and its application to GPS receivers

In this work,a novel prescaler based upon new current mode logic (CML) flip-flop architecture applied to global positioning system (GPS) receivers is proposed.Compared to traditional static current mode logic (CML) flip-flop,it introduces a clock-controlling transistor to reduce the time constant at sensing period.As a result,the speed has been maximized and the working range has been enlarged.The phase noise of local oscillator (LO) signals coming from the prescaler can be lowered by 6 dB,and the interfere...     

Temporal coordination and adaptation to rate change in music performance.

People often coordinate their actions with sequences that exhibit temporal variability and unfold at multiple periodicities. We compared oscillator- and timekeeper-based accounts of temporal coordination by examining musicians' coordination of rhythmic musical sequences with a metronome that gradually changed rate at the end of a musical phrase (Experiment 1) or at the beginning of a phrase (Experiment 2). The rhythms contained events that occurred at the same periodic rate as the metronome and at half the period. Rate change consisted of a linear increase or decrease in intervals between metronome onsets. Musicians coordinated their performances better with a metronome that decreased than increased in tempo (as predicted by an oscillator model), at both beginnings and ends of musical phrases. Model performance was tested with an oscillator period or timekeeper interval set to the same period as the metronome (1:1 coordination) or half the metronome period (2:1 coordination). Only the oscillator model was able to predict musicians' coordination at both periods. These findings suggest that coordination is based on internal neural oscillations that entrain to external sequences. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The dual-edge alignment technique with improved spur reduction effects in ring oscillators

In this paper, the technique of dual-edge phase-alignment and its effects on ring oscillators are presented. This technique provides resetting of the built-up jitter at both rising and falling edges of a clean aligning signal named as the reference. Using signals and systems theory, the effect of the technique on the spurs due to the aligning reference signal is completely analyzed. We show that adding properly the dual-edge aligning feature to phase-aligned ring oscillators cause the spurs in the neighborhood of the carrier to disappear. First, the validity of the results obtained from the derived analytical equations is verified through simulations using MATLAB. Then a complete circuit considering realistic models for its components is simulated in TSMC RF CMOS 0.18um process using ADS for further validation.     

A dynamic model for the efficiency optimization of an oscillatory low grade heat engine

A simple approach is presented for the modeling of complex oscillatory thermal-fluid systems capable of converting low grade heat into useful work. This approach is applied to the NIFTE, a novel low temperature difference heat utilization technology currently under development. Starting from a first-order linear dynamic model of the NIFTE that consists of a network of interconnected spatially lumped components, the effects of various device parameters (geometric and other) on the thermodynamic efficiencies of the device are investigated parametrically. Critical components are highlighted that require careful design for the optimization of the device, namely the feedback valve, the power cylinder, the adiabatic volume and the thermal resistance in the heat exchangers. An efficient NIFTE design would feature a lower feedback valve resistance, with a shorter connection length and larger connection diameter; a smaller diameter but taller power cylinder; a larger (time-mean) combined vapor volume at the top part of the device; as well as improved heat transfer behavior (i.e. reduced thermal resistance) in the hot and cold heat exchanger blocks. These modifications have the potential of increasing the relevant form of the second law efficiency of the device by 50% points, corresponding to a 3.8% point increase in thermal efficiency.     

Dynamic analysis of laminated composite plates subjected to a moving oscillator by FEM

This paper presents a finite element model based on the first order shear deformation theory to investigate the dynamic behavior of laminated composite plates traversed by a moving oscillator. The oscillator model is assumed to be consisting of two nodal masses that are connected by means of a spring-damper unit. The governing equations of motion of two sub-systems are separately integrated by applying the Newmark’s time integration procedure. Then, the obtained equations are coupled and the responses of system components are calculated in each time step. The accuracy of algorithm is verified by comparing the numerical results of static, free vibration and simplified moving force problems analysis with the available exact solutions and other numerical results in the literature. Also, the effects of mass ratio, damping ratio of system components, stiffness of suspension system, velocity and eccentricity of moving oscillator on dynamic responses is parametrically studied. This algorithm can be applied to various boundary conditions, lamination schemes and fiber angels.     

基于FPGA的高速软件无线电数字解调模块的分析

主要对载波恢复COSTAS环法中的NCO与数字滤波器进行了介绍 ,并对FPGA芯片的优缺点进行了简单的分析 ,使该模块能有效的完成载波恢复功能。