Output Characteristics of n-Buried-pSOI Sandwiched RF Power LDMOS

A novel n-buried-pSOI sandwiched structure for an RF power LDMOS is proposed. The output characteristics of the RF power LDMOS are greatly affected by the drain-substrate parasitic capacitance. The output characteristics become better as the drain-substrate parasitic capacitance decreases. Results show that the drain-substrate capacitance of the n- buried-pSOI sandwiched LDMOS is 46.6% less than that of the normal LDMOS,and 11.5% less than that of the n-buried- pSOI LDMOS,respectively. At l dB compression point,its output power is 188% higher than that of the normal LDMOS, and 10.6% higher than that of the n-buried-pSOI LDMOS, respectively. The power-added efficiency of the proposed structure is 38.3%. The breakdown voltage of the proposed structure is 11% more than that of the normal LDMOS.

Effect of cavity length detuning on the output characteristics for the middle infrared FEL oscillator of FELiChEM

FELiChEM is an infrared free electron laser（FEL） facility currently under construction, which consists of two oscillators generating middle-infrared and far-infrared laser covering the spectral range of 2.5–200 μm. In this paper, we numerically study the output characteristics of the middle-infrared oscillator with accurate cavity length detuning. Emphasis is put on the temporal structure of the micropulse and the corresponding spectral bandwidth.Taking the radiation wavelengths of 50 μm and 5 μm as examples, we show that the output pulse duration can be tuned in the range of 1–6 ps with corresponding bandwidth of 13%–0.2% by adjusting the cavity length detuning.In addition, a special discussion on the comb structure is presented, and it is indicated that the comb structure may arise in the output optical pulse when the normalized slippage length is much smaller than unity. This work has reference value for the operation of FELiChEM and other FEL oscillators.

Study of the output characteristics of nonlinear optical loop mirror on an erbium-doped mode-locked fiber laser

We experimentally discussed the output characteristics of a passively mode-locked erbium-doped fiber laser using a single-mode fiber(SMF)structure as a saturable absorber(SA)based on nonlinear optic loop mirror(NOLM).The NOLM acting as an SA has properties of controllable pulse interval and pulse width.Four different types of NOLMs are experimentally discussed and the results show that fine adjustment to the coupler ratio together with optimization of the SMF length inside the NOLM can simultaneously implement high pulse energy and pulse internal tunability.The laser configuration provides a method to generate well-performing mode-locked lasing,and the investigations of the effects of changing some parameters of the laser also provide some help for the development of mode-locked fiber laser based on NOLM.

Structure design and characteristics analysis of a cylindrical giant magnetostrictive actuator for ball screw preload

In order to achieve automatic adjustment of the double-nut ball screw preload, a magnetostrictive ball screw preload system is proposed. A new cylindrical giant magnetostrictive actuator （CGMA）, which is the core component of the preload system, is developed using giant magnetostrictive material （GMM） with a hole. The pretightening force of the CGMA is determined by testing. And the magnetic circuit analysis method is introduced to calculate magnetic field intensity of the actuator with a ball screw shaft. To suppress the thermal effects on the magnetostrictive outputs, an oil cooling method which can directly cool the heat source is adopted. A CGMA test platform is established and the static and dynamic output characteristics are respectively studied. The experimental results indicate that the CGMA has good linearity and no double-frequency effect under the bias magnetic field and the output accuracy of the CGMA is significantly improved with cooling measures. Although the output decreased with screw shaft through the actuator, the performance of CGMA meets the design requirements for ball screw preload with output displacement more than 26 μm and force up to 6200 N. The development of a CGMA will provide a new approach for automatic adjustment of double-nut ball screw preload.

Dark output characteristic of γ-ray irradiated CMOS digital image sensors

The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.

Difference in electron-and gamma-irradiation effects on output characteristic of color CMOS digital image sensors

Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have been studied in comparison to those from theγ-irradiated sensors. For the electron-irradiated sensors, the non-uniformity increases obviouslyand a small bright region on the dark image appears at the dose of 0.4 kGy. The average brightnessincreases at 0.4 kGy, increases sharply at 0.5 kGy. The picture is very blurry only at 0.6 kGy,showing the sensor undergoes severe performance degradation. Electron radiation damage is much moresevere than γ radiation damage for the CMOS image sensors. A possible explanation is presented inthis paper.

Analysis of Profile and Unsteady Flow Performance of Variable Base Circle Radius Scroll Expander

To study the complex internal flow field variation and output characteristics of a variable base radius scroll expander,this paper uses dynamic mesh techniques and computational fluid dynamics(CFD)methods to perform transient numerical simulations of a variable base radius scroll expander.Analysis of the flow field in the working cavity of a variable base radius scroll expander at different spindle angles and the effect of different profiles,speeds and pressures on the output characteristics of the scroll expander.The results of the study show that due to the periodic blocking of the inlet by the orbiting scroll,the fluid hits the internal walls of the expander at different flow rates,with excessive mechanical losses,resulting in an uneven distribution of the internal flow field.At the same temperature,pressure and scroll plate diameter,the variable base radius scroll expander increases the output torque by 0.046 N·m,the output power by 9.634 W and the isentropic efficiency by 3.8%compared to the fixed base circle scroll expander.As the speed is inversely proportional to the output torque,the isentropic efficiency of the expander tends to increase and then decrease as the speed increases.The density of the fluid is directly proportional to the pressure over a range of pressures.As the pressure increases from 0.6 to 0.9 Mpa,the average mass flow rate and isentropic efficiency increase by 0.02357 kg/s,and 6.61%,respectively.

Effect of an Asymmetric Doping Channel on Partially Depleted SOI MOSFETs

Asymmetric doping channel （AC） partially depleted （PD） silicon-on-insulator （SOI） devices are simulated using two-dimensional simulation software. The electrical characteristics such as the output characteristics and the breakdown voltage are studied in detail. Through simulations,it is found that the AC PD SOI device can suppress the floating effects and improve the breakdown characteristics over conventional partially depleted silicon-on-insulator devices. Also compared to the reported AC FD SOI device,the performance variation with device parameters is more predictable and operable in industrial applications. The AC FD SO1 device has thinner silicon film, which causes parasitical effects such as coupling effects between the front gate and the back gate and hot electron degradation effects.

Modeling and Analysis of a Random Excited Double-Clamped Piezoelectric Energy Harvester

A double-clamped piezoelectric energy harvester subjected to random excitation is presented,for which corresponding analytical model is established to predict its output characteristics.With the presented theoretical natural frequency and equivalent stiffness of vibrator,the closed-form expressions of mean power and voltage acquired from the double-clamped piezoelectric energy harvester under random excitation are derived.Finally theoretical analysis is conducted for the output performance of the doubleclamped energy harvester with the change of spectrum density（SD）of acceleration,load resistance,piezoelectric coefficient and natural frequency value,which is found to closely agree with Monte Carlo simulation and experimental results.

Realization of non HF air plasma cutting power source based on a complexisolated inverter

On the basis of analyzing and testing of common inverting circuits, a new type inverter, which has a special inverting circuit called complex isolated, has been put forward. In turn, an applicable air plasma cutting machine has also been put into use. Testing results show that this kind inverter has lots of properties as high reliability, high efficiency, good EMC(electromagnetic compatibility) and easy operating. The complex isolated inverting circuit can be considered as a quite valuable reference for the research of high power welding inverter.

Optimization Study on Expansion Energy Used Air-Powered Vehicle with Pneumatic-Hydraulic Transmission

Pneumatic-hydraulic transmission has been developed for years. However, its dynamic properties are not good enough for application. In this paper, in order to increase the output characteristics, a late-model air-powered vehicle using expansion energy is proposed which can boost energy through a pneumatic-hydraulic transmission. The dynamic characteristics of the air-powered vehicle is modeled and verified by conducting experiment. In addition,the influence of the key parameters of the air-powered vehicle is researched for the optimization of the system performance. Through the results, the author got the conclusion that, firstly, comparison of the results of model and experiment proves the built model to be effective; secondly, input air pressure should be set according to the request of the practical loads, and range of 0.65 to 0.75 MPa can be chosen; thirdly, as a key structure parameter of the airpowered vehicle, ratio of the areas is considered to be set to approximate 8; what’s more, a bigger orifice with a limit will promote the system dynamic characteristic property, and the limit is about 3.5 mm; last but not the least, not too farther position of the rings will increase the quality of output dynamic characteristics. This paper can be a reference for system design of air-powered vehicle and dynamic improvement.

Research on the controller of an arc welding process based on a PID neural network

A controller based on a PID neural network （PIDNN） is proposed for an arc welding power source whose output characteristic in responding to a given value is quickly and intelligently controlled in the welding process. The new method syncretizes the PID control strategy and neural network to control the welding process intelligently, so it has the merit of PID control rules and the trait of better information disposal ability of the neural network. The results of simulation show that the controller has the properties of quick response, low overshoot, quick convergence and good stable accuracy, which meet the requirements for control of the welding process.

Elastic energy storage technology using spiral spring devices and its applications:A review

Harvesting and storing energy is a key problem in some applications.Elastic energy storage technology has the advantages of wide-sources,simple structural principle,renewability,high effectiveness and environmental-friendliness.This paper elaborates the operational principles and technical properties and summarizes the appli-cability of elastic energy storage technology with spiral springs.Elastic energy storage using spiral spring can realize the balance between energy supply and demand in some applications.Continuous input-spontaneous out-put working style can provide simple energy sources for short-time energy supply,and provide strong moment impact and rapid start,or realize the energy conservation for reciprocating movement.Uniform output working style can realize energy output with uniform speed for timekeeping and load-driving.Random input working style can harvest and store random mechanical energy or convert small torque into a large moment to drive external loads.Finally,this paper proposes new researches and developments of elastic energy storage technology on new materials and structures,mechanical properties and structural dynamics analyses,design and control for new functions.

Theoretical study on rotary-sliding disk triboelectric nanogenerators in contact and non-contact modes

The triboelectric nanogenerator （TENG） has emerged as a new and effective mechanical energy harvesting technology. In this work, a theoretical model for a rotary-sliding disk TENG with grating structure was constructed, including the dielectric-to-dielectric and conductor-to-dielectric cases. The finite element method （FEM） was utilized to characterize the fundamental physics of the rotary- sliding disk TENG working in both contact and non-contact modes. The basic properties of disk TENG were found to be controlled by the structural parameters such as tribo-surface spacing, grating number, and geometric size. From the FEM calculations, an approximate V-Q-a relationship was built through the inter- polation method, and then the TENG dynamic output characteristics with arbitrary load resistance were numerically calculated. Finall~ the dependencies of output power and matched resistance on the structural parameters and rotation rate were revealed. The present work provides an in-depth understanding of the working principle of the rotary-sliding disk TENG and serves as important guidance for optimizing TENG output performance in specific applications.

A statistical model for the design of rotary HTS flux pumps based on deep-learning neuron network

Rotory high temperature superconducting(HTS)flux pumps can consistently generate a DC voltage by rotating magnets over superconducting tapes,and thus energize the circuit if a closed loop is formed.The voltage output is a crucial factor to reflect the performance of such an HTS flux pump,which is determined by a set of design specifications,and some of them have been investigated extensively in the current literature.However,no work has been done yet to study the HTS dynamo output voltage by efficiently integrating all the design parameters together.In this paper,a well‐trained deep‐learning neuron network(DNN)with back‐propagation algorithms has been put forward and validated.The proposed DNN is capable of quantifying the output voltage of an HTS dynamo instantly with an overall accuracy of approximately 98%with respect to the simulated values with all design parameters explicitly specified.The model possesses a powerful ability to characterize the output behavior of HTS dynamos by considering multiple design parameters,e.g.,airgap,superconductor tape width,operating frequency,remanent flux density,rotor radius,and permanent magnet width,which have covered all the typical design considerations.The output characteristics of an HTS dynamo against each of the design parameters have been successfully demonstrated using this model.Compared to conventional time‐consuming finite element method(FEM)based numerical models,the proposed DNN model has the advantages of automatic learning,fast computation,as well as strong programmability.Therefore the DNN model can greatly facilitate the design and optimization process for HTS dynamos.An executable application has been developed accordingly based on the DNN model,which is believed to provide a useful tool for learners and designers of HTS dynamos.