Influence of electron irradiation on the switching speed in insulated gate bipolar transistors

The influence of electron irradiation on the switching speed in insulated gate bipolar transistors（IGBT） with different epitaxial layer thicknesses is discussed in detail.The experimental results prove that the fall time of IGBT increases when increasing the thickness of the epitaxial layer.However,there is no obvious difference between the ratios of the fall time after irradiation to those before irradiation for different epitaxial layer thicknesses.The increase in switching speed of the IGBT is accompanied by an increase in the forward drop,and a trade-off curve between forward voltage drop and fall time of IGBT is presented.

Numerical Simulation on a Throttle Governing System with Hydraulic Butterfly Valves in a Marine Environment

Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve.It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid.

A novel optical burst switching architecture for high speed networks

A novel optical burst switching （OBS） high speed network architecture has been proposed. To verify its feasibility and evaluate its performance, just-enough-time （JET） signaling has been considered as a high performance protocol. In the proposed architecture, to avoid burst losses, firstly, a short-prior- confirmation-packet （SPCP） is sent over the control channel that simulates the events that the actual packet will experience. Once SPCP detects a drop at any of the intermediate nodes, the actual packet is not sent but the process repeats. In order to increase network utilization, cost effectiveness and to overcome some limitations of conventional OBS, inherent codes （e.g., orthogonal optical codes （OOC））, which are codified only in intensity, has been used. Through simulations, it shows that a decrease in burst loss probability, cost effectiveness and a gain in processing time are obtained when optical label processing is used as compared with electronic processing.

AN EFFECTIVE MODEL TO EVALUATE BLOCKING PROBABILITY OF TIME-SLOTTED OPTICAL BURST SWITCHED NETWORKS

Time-slotted optical burst switched network is a potential technique to support IP over Wavelength Division Multiplexing (WDM) by introduce Time Division Multiplexing (TDM) channel to Optical Burst Switching (OBS) technology. This paper presents a framework to evaluate blocking performance of time-slot-ted OBS networks with multi-fiber wavelength channels. The proposed model is efficient for not only single class traffic such as individual circuit switch traffics or best-effort traffics but also mixed multi-class traffics. The effectiveness of the proposed model is validated by simulation results. The study shows that blocking per-formance of multi-fiber TS-OBS network is acceptable for future Internet services.

Double gate lateral IGBT on partial membrane

A new SOILIGBT（lateral insulated-gate bipolar transistor） with cathode-and anode-gates on partial membrane is proposed.A low on-state resistance is achieved when a negative voltage is applied to the anode gate.In the blocking state,the cathode gate is shortened to the cathode and the anode gate is shortened to the anode,leading to a fast switching speed.Moreover,the removal of the partial silicon substrate under the drift region avoids collecting charges beneath the buried oxide,which releases potential lines below the membrane,yielding an enhanced breakdown voltage（BV）.Furthermore,a high switching speed is obtained due to the absence of the drain-substrate capacitance. Lastly,a combination of uniformity and variation in lateral doping profiles helps to achieve a high BV and low special on-resistance.Compared with a conventional LIGBT,the proposed structure exhibits high current capability,low special on-resistance,and double the BV.