真空压膜改良式Activator和传统肌激动器比较研究

目的:探讨将真空成型改良式Activator与传统肌激动器从制作、矫治器结构、配戴和临床效果进行对比研究,以明确两种矫治器临床应用特点,为临床应用提供依据。方法:将试验组和对照组各16例分别配戴真空成型改良式Activator和传统肌激动器,拍治疗前后头颅定位侧位片。用X线头影测量分析方法分析治疗前后X线测量数据,并分析对比。结果:试验组与对照组比较,有统计学意义共5项,其中非常显著统计学意义是U6-PP,有显著统计学意义是Co-Pg、U1-SN、U1-NA距和∠N'-Pg'-FH,临床疗效显著。结论:试验组以机器代替人力,无毒操作,省时经济,矫治器隐形舒适,依从性良好,可缩短疗程,矫治效果更显著,可推广应用。

Flow Control with Intermittent Disturbance for the Laminar Separation Bubble on a NACA633-421 Airfoil

This study investigates the aerodynamic performance of the NACA 633-421 airfoil and the effectiveness and feasibility of intermittent disturbance flow control methods on laminar separation bubbles(LSBs).It is found that the average velocity and influence range of the synthetic jet actuator increase with the increasing of driving frequency and driving amplitude.LSB occurs at Re=1.0×10^(5),and ruptures atα=6°.But with intermittent disturbance control,the stall angle of attack(AoA)increases while significantly reducing drag.Research shows that although certain disturbance cannot fully recover from LSB stall,decreasing driving amplitude partially restores wing aerodynamic performance,more effectively than increasing driving amplitude.

A 1.25Gb/s InP-Based Vertical Monolithic Integration of an MQW Laser Diode and an HBT Driver witha Lateral Buffer Mes a Structure

A novel fabrication process related to a smoothly wet chemical etching profile o f InP-based epitaxial layers in the crystal direction of [01for an InP-based monol ithic vertically integrated transmitter with an MQW laser diode and a heterojunction bipolar tran sistors driver circuit is described.A clear eye output diagram via an O/E converter is demonstrat ed und er a 1.25Gb/s non-return-zero pseudorandom code with a pattern length of 2 the integrated transmitter has a power dissipation of about 120mW with an optical output of 2dBm.

0.6μm CMOS Laser Diode Driver for Optical Access Networks

Using native CMOS technology,EDA tool,and adopting full-custom design methodology,a laser diode driver for the use of STM-1 and STM-4 optical access network,is realized by CSMC-HJ 0.6μm CMOS technology to modulate laser diodes at 155Mb/s (STM-1),622Mb/s (STM-4) with adjustable modulation current from 0 to 50mA for an equivalent 50Ω load.The maximum modulation voltage is over 2.5V pp corresponding to a 3V DC bias for output stage.The time range of rise and fall from 360ps to 471ps is measured from the output voltage pulse.The RMS jitter is no more than 30ps for four bit rates.The power consumption is less than 410mW under a power supply voltage of 5V.According to the experimental results,the laser diode driver achieves the same level as their counterparts worldwide.

EXPERIMENTAL INVESTIGATION ON INDUCED FLOW VELOCITY OF PLASMA AERODYNAMIC ACTUATION

Plasma flow control is an active flow control technology that based on the plasma aerodynamic actuation. It can be used to enhance the aerodynamic characteristics of aircraft and propulsion systems. To study the phenomena occurring in plasma aerodynamic actuation and the mechanism of plasma flow control, the induced flow velocity of the plasma aerodynamic actuator is experimentally investigated under a variety of parameter conditions. The results indicate that plasma aerodynamic actuation accelerates the near surface air at velocities of a few meters per second, and there is an angle about 5° between the mainstream and the actuator wall and a spiral vortex is formed when the induced flow is moving along the wall. Besides, with the fixed frequency, the induced flow velocity increases linearly with the applied voltage, but it is insensitive to the frequency when the applied voltage is fixed. And the configuration is an effective factor for the performance of the plasma aerodynamic actuator.

Implementation of a DC-10Mb/s 0.5μm CMOS Laser Diode Driver

A DC-10Mb/s laser diode driver,compatible with TTL and CMOS levels,is presented. The optical power corresponding to‘1＇ and ‘0＇ can be set independently with resistors off-chip and stabilized with a closed loop. A novel peak-to- peak optical power monitor and stabilization mechanism is introduced. The circuit, fabricated in a CSMC 0. 5μm mixed signal CMOS process, can provide 120mA maximum drive current and 0. 6dB extinction ration fluctuation over - 20 ＋ 80℃ ,which is independent of input pattern.

A Novel Three-Section Self-Pulsating DFB Laser with Hybrid Grating

A 1.55μm InGaAsP-InP three-section DFB laser with hybrid grating is fabricated and self-pulsations （SP） with frequencies around 20GHz are observed. The mechanism of SP generation in this device is researched. Furthermore,the important role of the phase tuning section on the SP is investigated.

Mechanism of electro-hydraulic exciter for new tamping device

A new tamping device which is driven by an electrohydraulic exciter was proposed to overcome the limitations of mechanically driven devices.The double-rod oscillation cylinder drives the tamping arm to realize vibration.A new spin valve was designed in order to fulfill dynamic state requirements of the oscillation cylinder.Parametric analysis was carried out by establishing mathematic model.Then,the relationships among the structure of valve port and the frequency,amplitude,output shock force of the cylinder were researched.An experimental device of the electrohydraulic exciter was established to validate the theoretical results.The signals were acquired by AVANT dynamic signal analyser of vibration.The results show that new tamping device can satisfy all kinds of complex working conditions with the flexible adjustment of frequency and amplitude.

Stochastic Resonance in a Single-Mode Laser Driven by Quadratic Colored Pump Noise:Effects of Biased Amplitude Modulation Signal

A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedure.Itis found that there are three different typies of stochastic resonance in the model:the conventional form of stochasticresonance,the stochastic resonance in the broad sense,and the bona fide SR.

Pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer

This paper presents the construction of a pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is composed of fuzzy and disturbance controls, and the active control force is constructed by actuating a pneumatic actuator. A phase lead-lag compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension improves much the vibration suppression of the car model.

Detection Techniques of Femtosecond Lasers

The measurement techniques of femtosecond spectroscopy are effective method to investigate ultrafast dynamics, they are widely used in the fields of physics, chemistry and biology. In this paper, the principle, experiment setup and the approaches to deal with the experiment data were presented. Then different measurement techniques such as transient absorption spectroscopy, photon echoes, optical Kerr effect and degenerate four-wave mixing were explained with special examples. At last, the application prospect of measurement techniques of femtosecond spectroscopy was forecasted.

Maglev self-excited vibration suppression with a virtual sky-hooked damper

This work addresses the problem of self-excited vibration,which degrades the stability of the levitation control,decreases the ride comfort,and restricts the construction cost of maglev system.Firstly,a minimum model containing a flexible bridge and a single levitation unit is presented.Based on the simplified model,the principle underlying the self-excited vibration is explored.After investigations about the energy transmission between the levitation system and bridge,it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-excited vibration may be avoided.To enlarge the equivalent modal damping of bridge,the sky-hooked damper is adopted.Furthermore,to avoid the hardware addition of real sky-hooked damper,considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper,the technique of the virtual sky-hooked damper is proposed.The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated.Finally,numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.

New Type of 2-D Laser Doppler Vibrometer

The fundamentals and method of 2 D laser Doppler vibrometer are introduced.The factors influencing the measuring accuracy are analyzed. Moreover, the circuit for signal processing is designed. The vibrating amplitude and frequency of 2 D vibration in wider range can be measured simultaneously in non contact means,the measuring results are accurate.

Scan matching using line segment relationships for map-based localization of mobile robot

A new scan matching method for mobile robot localization is presented, which takes line segment as the feature and matches the real scans in the given reference map by relationships of the directional-defined line segments. The alignment was done by hierarchically identifying the multiple relationships and the result was recorded in a correspondence matrix, where the best match is defined and selected for localization. It is indicated that the searching algorithm of the best match can find the ambiguities and get rid of them. This method with less computational cost works well in occluded environment, and can correct the error in pose estimation without the need for the estimation itself. The efficiency, accuracy and robustness of this method were verified by experiments of localization in an occluded environment and a long-distance indoor navigation.

Ultrasonic Linear Motor with Anisotropic Composite

An idea to make up the vibrating body of ultrasonic motor with anisotropic composite is proposed and a linear piezoelectric motor is developed in this paper. Relative problems such as actuating mechanism, resonant frequency are discussed theoretically. According to the feature that impulse exists between the elastic body of composite ultrasonic linear motor and the base, an impulse analysis is presented to calculate the motor′s friction driving force and frictional conversion efficiency. The impulse analysis essentially explains the reason why the ultrasonic motor has great driving force, and can be applied to analyze the non-linear ultrasonic motor.

Self-Optimizing Flexible Assembly Systems

Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industrial turbulent environments. Flexible automated systems are requested in order to improve dynamic production efficiency, e.g. robot-based hardware and PC-based controllers, but these usually induce a significantly higher production complexity, whereby the efforts for planning and programming, but also setups and reconfiguration, expand. In this paper a definition and some concepts of self-optimizing assembly systems are presented to describe possible ways to reduce the planning efforts in complex production systems. The concept of self-optimization in assembly systems will be derived from a theoretical approach and will be transferred to a specific application scenario---the automated assembly of a miniaturized solid state laser--where the challenges of unpredictable influences from e.g. component tolerances can be overcome by the help of self-optimization.

Realization of a tunable analog predistorter using parallel combination technique for laser driver applications

This paper describes a new approach for designing analog predistorters that can compensate for the nonlinear distortion of laser drivers in a radio-over-fiber （RoF） system. In contrast to previous works, this paper analyzes the transfer characteristics of CMOS transistors, by combining parallel currents of CMOS transistors in various W/L and negative bias voltages to realize the tunable analog predistortion function. The circuit is fabricated by a standard 0.18txm CMOS technology. The core circuit current consumption is only 15mA and the entire driver circuit works in a band-pass from 1 - 2.2GHz. Experimental results of two-tone tests have shown that with an analog predistortoer the IIP3 of the laser driver circuit has an improvement of 4.91 dB.

An electrophoretic display driving waveform based on improvement of activation pattern

Electrophoretic display(EPD) technology has become one of the main supporting pillars of the electronic paper display industry.Despite its benefits,the EPD technology suffers from several disadvantages such as non-fixed threshold voltage value for gray scale display.In addition,the display has to repeatedly refresh between white and black states to eliminate ghost image when it needs to update a new image.The traditional driving waveform for the EPD includes four stages: erasing the original image,resetting to black state,clearing to white state,and writing a new image.A flicker can be found when transferring between two adjacent stages.A new driving waveform based on the improvement of activation pattern is proposed to weaken the ghost image and reduce the flicker.Experimental results show that the proposed driving waveform could weaken the ghost image effectively and reduce the number of flickers by 50%.Compared with the traditional driving waveform,the driving waveform of this work has a better performance.

Angle Control of a Pneumatically Driven Musculoskeletal Model Based on Coordination of Agonist-Antagonist Muscle

In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry （e.g., service, medical, and aging care）. Such robots must be safe and flexible so that they can coexist with people. Pneumatic actuators are useful for achieving this goal because they are lightweight units with natural compliance. Our research focuses on joint angle control for a pneumatically driven musculoskeletal model. In such a model, we use a one-degree-of-freedom joint model and a five-fingered robot hand as test beds. These models are driven by low pressure-driven pneumatic actuators, and mimic the mechanism of the human hand and musculoskeletal structure, which has an antagonistic muscle pair for each joint. We demonstrated a biologically inspired control method using the parameters antagonistic muscle ratio and antagonistic muscle activity. The concept of the method is based on coordination of an antagonistic muscle pair using these parameters. We have investigated the validity of the proposed method both theoretically and experimentally, developed a feedback control system, and conducted joint angle control by implementing the test beds.

A 155 Mbps laser diode driver with automatic power and extinction ratio control

An integrated laser diode driver(LDD) driving an edge-emitting laser diode was designed and fabricated by 0.35 μm BiCMOS technology. This paper proposes a scheme which combines the automatic power control loop and temperature com-pensation for modulation current in order to maintain constant extinction ratio and average optical power. To implement tem-perature compensation for modulation current,a novel circuit which generates a PTAT current by using the injecting base current of a bipolar transistor in saturation region,and alternates the amplifier feedback loop(closed or not) to control the state of the current path is presented. Simulation results showed that programmed by choice of external resistors,the IC can provide modu-lation current from 5 mA to 85 mA with temperature compensation adjustments and independent bias current from 4 mA to 100 mA. Optical test results showed that clear eye-diagrams can be obtained at 155 Mbps,with the output optical power being nearly constant,and the variation of extinction ratio being lower than 0.7 dB.