焊带对光伏组件的光学增益及表征方法

基于全反射原理,建立焊带性能评估的表征方法--焊带光学利用率;通过该方法计算出反光或圆形焊带比常规型焊带多2.5倍以上反射光利用率。建立光伏组件光学增益近似估算模型,根据该模型可预估出不同类型焊带对光伏组件的功率增益。通过模型计算分析,试验中使用的反光焊带和圆形焊带可分别实现五主栅单晶光伏组件约0.6%和2.2%的光学增益,为高效低成本组件提供研究方向。

Adaptive Spectr um Decision Method for Heterogeneous Cognitive Radio Networks

To improve spectrum utilization and minimize interference to Primary User (PU), an adaptive spectrum decision method is proposed for Secondary User (SU), while taking traffic load balancing and spectrum heterogeneity into consideration. Long-term statistics and current sensing results are integrated into the proposed decision method of spectrum access. Two decision methods, namely probability based and sensing based, are presented, compared and followed by performance analysis in terms of delay. For probability based spectrum decision, Short-Time-Job-First (STJF) priority queuing discipline is employed to minimize average residual time and theoretical conclusion is derived in a novel way. For sensing based decision we treat the interrupted service of SU as newly incoming and re-decision process is initialized to find available spectrum in a First-Available-First-Access (FAFA) fashion. Effect of sensing error in PHY layer is also analyzed in terms of extended average residual time. Simulation results show that, for relatively low arriving rate of SU traffic, the proposed spectrum decision method yields at least a delay reduction of 39.5% compared with non-adaptive method. The proposed spectrum decision can significantly improve delay performance even facing sensing errors, which cause performance degeneration to both PU and SU.

A Novel Optical Burst Mesh Network with Optical Time Slot Interchange at Source Nodes

In this paper, we propose an optical burst network architecture supporting the ge- netic mesh topology. The intermediate node architecture of the mesh network can be the same with current wavelength switching Wave- length Division Multiplexing （WDM） net- works, and thus can reuse existing deployed infrastructure. We employ a novel Optical Time Slot Interchange （OTSI） at the source nodes for the first time to mitigate the burst conten- tion and to increase the bandwidth utilization. Time- and wavelength-domain reuse in the OTSI significantly saves optical components and red- uces blocking probability.

Transmission Mechanism Based on Burst Filling in Hybrid Optical Burst/Circuit Switching Networks

Hybrid optical switching networks make full use of the advantages of Optical Circuit Switching(OCS)and Optical Burst Switching(OBS).In parallel hybrid optical switching networks,edge nodes choose a switching mode for traffic and no longer change.The inflexible decision making of the traffic transfer mode leads to low resource utilization when the arrival rate of the OCS traffic is lower than the capacity of the light path.In this paper,a new transmission scheme is proposed to improve resource utilization for hybrid optical switching networks.When the traffic arrival rate of the light path is lower than the transmission rate of the light path,the OCS traffic flow is reshaped at the edge nodes to generate a series of voids.Then,several message packets are sent along the light path to inform the core nodes of the voids of the light paths that represent the unused bandwidth resources.To improve the resource utilization,the voids can be filled with data bursts by core nodes.The simulation results show that the new scheme can effectively reduce the burst loss rate and improve the link utilization of the hybrid optical switching network on the premise of a providing service quality guarantee for OCS traffic.

Visible-light-promoted and photocatalyst-free trifluoromethylation of enamides

An efficient and practical method is developed for the trifluoromethylation of enamides using Umemoto's reagent as the trifluoromethylating reagent. These reactions proceeded under visible light irradiation without any photocatalyst at room temperature in good chemical yields.