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991.
Chia‐Wei Chen Hung‐Wei Tsai Yi‐Chung Wang Yu‐Chuan Shih Teng‐Yu Su Chen‐Hua Yang Wei‐Sheng Lin Chang‐Hong Shen Jia‐Ming Shieh Yu‐Lun Chueh 《Advanced functional materials》2019,29(48)
In this work, for the first time, the addition of aluminum oxide nanostructures (Al2O3 NSs) grown by glancing angle deposition (GLAD) is investigated on an ultrathin Cu(In,Ga)Se2 device (400 nm) fabricated using a sequential process, i.e., post‐selenization of the metallic precursor layer. The most striking observation to emerge from this study is the alleviation of phase separation after adding the Al2O3 NSs with improved Se diffusion into the non‐uniformed metallic precursor due to the surface roughness resulting from the Al2O3 NSs. In addition, the raised Na concentration at the rear surface can be attributed to the increased diffusion of Na ion facilitated by Al2O3 NSs. The coverage and thickness of the Al2O3 NSs significantly affects the cell performance because of an increase in shunt resistance associated with the formation of Na2SeX and phase separation. The passivation effect attributed to the Al2O3 NSs is well studied using the bias‐EQE measurement and J–V characteristics under dark and illuminated conditions. With the optimization of the Al2O3 NSs, the remarkable enhancement in the cell performance occurs, exhibiting a power conversion efficiency increase from 2.83% to 5.33%, demonstrating a promising method for improving ultrathin Cu(In,Ga)Se2 devices, and providing significant opportunities for further applications. 相似文献
992.
993.
Wei Zhou Qun Li Yi‐fan Zhu Hua He 《International Journal of Satellite Communications and Networking》2019,37(6):561-570
This study is extended to construct the network model, the node model, and the link model of complex communication network for satellite navigation system (CCN‐SNS) based on the hierarchical architecture. Firstly, a method called snapshots was proposed to describe the dynamic topology for CCN‐SNS; secondly, another method was put forward to model the different nodes of the CCN‐SNS; thirdly, the different links between every two different nodes were modeled. Therefore, based on the OPNET tools, a simulation for the CCN‐SNS, which contains the models that proposed earlier used to analyze the navigation accuracy and network transmission performance, was performed. 相似文献
994.
Chien‐Ching Chiu Yi‐Xiang Tong Yu‐Ting Cheng 《International Journal of Communication Systems》2019,32(9)
In this paper, ultrawide band (UWB) communication systems with eight transmitting and receiving ring antenna arrays are implemented to test the bit error rate and capacity performance. By using the ray‐tracing technique to compute any given indoor wireless environment, the impulse response of the system can be calculated. The synthesized beamforming problem can be reformulated into a multiobjective optimization problem. Self‐adaptive dynamic differential evolution (SADDE) and particle swarm optimization (PSO) are used to find the excitation current and the feed line length of each antenna to form the appropriate beam pattern. This pattern can then reduce the bit error rate and increase the channel capacity and receiving energy. Numerical results show that the fitness value and the convergence speed by the SADDE are better than those by the PSO. Moreover, the SADDE had better results for both line‐of‐sight and nonline‐of‐sight cases. In other words, compared with PSO, SADDE has improved more effectively the main beam radiation energy and reduced the multipath interference. 相似文献
995.
996.
We observed and analyzed the acid and HEBUT alkaline of Cu chemical mechanical polishing(CMP)slurry to evaluate their effects. Material analysis has shown that the planarity surfaces and the removal rate of alkaline slurry are better than the acid slurry during metal CMP processes. The global surface roughness and the small-scale surface roughness by 1010 m2 of copper film polished by the SVTC slurry are 1.127 nm and2.49 nm. However, it is found that the surface roughnesses of copper films polished by the HEBUT slurry are 0.728 nm and 0.215 nm. All other things being equal, the remaining step heights of copper films polished by the SVTC slurry and HEBUT slurry are respectively 150 nm and 50 nm. At the end of the polishing process, the dishing heights of the HEBUT slurry and the SVTC slurry are approximately both 30 nm, the erosion heights of the HEBUT slurry and the SVTC slurry are approximately both 20 nm. The surface states of the copper film after CMP are tested,and the AFM results of two samples are obviously seen. The surface polished by SVTC slurry shows many spikes.This indicates that the HEBUT alkaline slurry is promising for inter-level dielectric(ILD) applications in ultra large-scale integrated circuits(ULSI) technology. 相似文献
997.
998.
利用等差数列构造大围长准循环低密度奇偶校验码 总被引:7,自引:0,他引:7
针对准循环低密度奇偶校验(QC-LDPC)码中准循环基矩阵的移位系数确定问题,该文提出基于等差数列(AP)的确定方法。该方法构造的校验矩阵的围长至少为8,移位系数由简单的数学表达式确定,节省了编解码存储空间。研究结果表明,该方法对码长和码率参数的设计具有较好的灵活性。同时表明在加性高斯白噪声(AWGN)信道和置信传播(BP)译码算法下,该方法构造的码字在码长为1008、误比特率为10-5时,信噪比优于渐进边增长(PEG)码近0.3 dB。 相似文献
999.
提出了一种适用于强度调制直接检测(IM/DD) 光系统的信号调制格式。这种基于Nyquist脉冲half cycle副载波调制(SCM)信号能有效提高频谱效率,为了减少传递函数引起的系统的性能 恶化,采 用了数字预均衡和后均衡实现对光纤损伤的补偿;建立了偏振复用(PDM)IM/DD系统 平台, 分析了Nyquist脉冲SCM信号在系统中的PAPR性能,实现了72Gbit/s 64-QAM N yquist脉冲SCM信号经过20km标准单模光纤(SMF)传输后其误码性能 小于前向纠错(FEC)阀值3.8×10-3。 相似文献
1000.