Development of Surface Grating Distributed Feedback Quantum Cascade Laser for High Output Power and Low Threshold Current Density

We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.

Cooperative output tracking of multi-agent systems under finite time

The cooperative output tracking problem of multi-agent systems in finite time is considered.In order to enable the agents to quickly track and converge to external system within a finite time,a novel distributed output feedback control strategy based on the finite-time state observer is designed.This distributed finite-time observer can not only solve cooperative output tracking problems when the agents can not get external system signal,but also make the systems have a faster convergence and a good robustness.The stability of the system in finite time is proved based on Lyapunov function.Numerical simulations results have been provided to demonstrate the effectiveness of the proposed protocol.

Multi-Model Based PSO Method for Burden Distribution Matrix Optimization With Expected Burden Distribution Output Behaviors

Burden distribution is one of the most important operations, and also an important upper regulation in blast furnace(BF) iron-making process. Burden distribution output behaviors(BDOB) at the throat of BF is a 3-dimensional spatial distribution produced by burden distribution matrix(BDM),including burden surface output shape(BSOS) and material layer initial thickness distribution(MLITD). Due to the lack of effective model to describe the complex input-output relations,BDM optimization and adjustment is carried out by experienced foremen. Focusing on this practical challenge, this work studies complex burden distribution input-output relations, and gives a description of expected MLITD under specific integral constraint on the basis of engineering practice. Furthermore, according to the decision variables in different number fields, this work studies optimization of BDM with expected MLITD, and proposes a multi-mode based particle swarm optimization(PSO) procedure for optimization of decision variables. Finally, experiments using industrial data show that the proposed model is effective, and optimized BDM calculated by this multi-model based PSO method can be used for expected distribution tracking.

How Does the General Output Quantity Distribution of Suppliers Affect the Value-appropriation of Supply Chain？

This paper studies the problem of value-appropriation of supply chain, which is composed of a monopoly manufacturer downstream and multiple suppliers upstream. Firstly, we introduce two special examples in which output distribution of suppliers satisfy equal or equal-difference sequence. It is found that the more difference the distribution will be, the less preference will be gain by the manufacturer in the value-appropriation of supply chain. For the general distribution, the parameter ＂competitive residual＂ is introduced to score the influence of the suppliers＇ output quantity distribution on manufacturer＇s preference. The general conclusion will be given and it can directly deduce the conclusions above. Finally, we extend our basic conclusion to the more general situation in which the numbers of suppliers are not equal.

Experimental study of channel electron multiplier

Background Channel electron multiplier(CEM)can be used to measure extremely few charged particles,such as electrons and ions.The CEM is widely used in particle detection,so it is very important to study their performance parameters.Purposes Test and analyze the performance parameters of the CEM,such as resistance,gain,and pulse output for a single entrance photoelectron.Methods The heated tantalum filament is used as a stable and adjustable planar electron source to test the performance of the CEM in the analog mode.The performance parameters of the CEM in the pulse counting mode are tested by using the ultraviolet LED to excite the gold photocathode to generate a single photoelectron.Results and conclusions The gain of the CEM in the analog mode can reach more than 106 and the gain in the pulse counting mode can be two orders of magnitude higher.The curved helical channel has a greater advantage than the ordinary straight channel,which is conducive to weakening the ion feedback phenomenon.