A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the mai...A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs.In this work,we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.This method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovskite film.Furthermore,modification of the NiO_(x)/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization.As a result,a large-area perovskite film possessing larger grains,fewer pinholes,and reduced defects could be achieved.The inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved stability.This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.展开更多
An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can...An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can be formed by changing the dispersion of dispersion element and the bandwidth of shaped spectrum in this scheme. In the experiment, non-return-to-zero(NRZ) signal with bit rate of 29.41 Gbit/s and 1/2 duty ratio return-to-zero(RZ) signal with bit rate of 13.51 Gbit/s are obtained. The maximum bit rate of modulation format signal is also analyzed.展开更多
Achieving industrial-level electrochemical CO_(2)reduction to formate remains a significant challenge due to limitations in catalyst selectivity and interfacial proton management at high current densities.In a recent ...Achieving industrial-level electrochemical CO_(2)reduction to formate remains a significant challenge due to limitations in catalyst selectivity and interfacial proton management at high current densities.In a recent study,Prof.Guo and colleagues report the development of Turingstructured electrocatalysts,which incorporate reaction-diffusion-inspired topologies to engineer mesoscale surface patterns.This design enables precise modulation of the interfacial microenvironment,enhancing CO_(2)activation and suppressing competing hydrogen evolution.The resulting catalysts achieve efficient and stable CO_(2)-to-formate conversion under industrially relevant conditions,offering a promising strategy for scalable carbon-neutral chemical production.展开更多
118 kinds of Pt-Zr phases were established and investigated by considering various structures. Then the related physical properties, such as structural stability, lattice constants, formation enthalpies, elastic const...118 kinds of Pt-Zr phases were established and investigated by considering various structures. Then the related physical properties, such as structural stability, lattice constants, formation enthalpies, elastic constants and bulk moduli, are obtained by ab initio calculations. Based on the calculated results of formation enthalpies, the ground-state convex hull is derived for the Pt-Zr system. The calculated physical data would provide a basis for further thermodynamic calculations and atomistic simulations. For these Pt-Zr compounds, it is found there are a positive linear correlation between the formation enthalpies and atomic volumes, and a negative linear correlation between the bulk modules and atomic volumes.展开更多
为了提升未来弹性光网络的性能,提出了一种基于幅值密度特征的调制格式识别方法。该方法将幅值密度特征作为改进的Mobile Net V2模型的输入,通过特征识别确定调制格式类型,并引入了归一化注意力机制(NAM),实现对传输信号调制格式的精准...为了提升未来弹性光网络的性能,提出了一种基于幅值密度特征的调制格式识别方法。该方法将幅值密度特征作为改进的Mobile Net V2模型的输入,通过特征识别确定调制格式类型,并引入了归一化注意力机制(NAM),实现对传输信号调制格式的精准识别。在28 GBaud正交相移键控(QPSK)、8电平正交幅度调制(8QAM)、16QAM、32QAM、64QAM和128QAM传输系统中验证了该方案的可行性。实验结果表明:每种调制格式在达到100%识别准确率时所需的最低光信噪比(OSNR)均低于其对应的20%前向纠错(FEC)阈值,而且,在较宽的OSNR范围内达到了99.62%的识别准确率;在存在残余色散的光网络中,该方案仍能保持较高的识别性能。展开更多
针对现有光通信系统中调制格式识别的准确率问题,提出一种结合网格密度峰值聚类(Grid-Based Density Peaks Clustering Algorithm,GDPC)与点阵拟合模板匹配的识别方法。该方法充分考虑了多进制正交振幅调制(Multiple Quadrature Amplitu...针对现有光通信系统中调制格式识别的准确率问题,提出一种结合网格密度峰值聚类(Grid-Based Density Peaks Clustering Algorithm,GDPC)与点阵拟合模板匹配的识别方法。该方法充分考虑了多进制正交振幅调制(Multiple Quadrature Amplitude Modulation,MQAM)与多进制数字相位调制(Multiple Phase Shift Keying,MPSK)星座图的空间分布特征,并通过改进的聚类与匹配策略提升识别性能。相较于传统密度峰值聚类(Density Peaks Clustering Algorithm,DPC),GDPC采用网格划分策略对数据空间进行离散化,从而优化密度估计过程,提高聚类中心的提取精度。此外,引入最小二乘法进行点阵拟合,通过最小残差准则实现星座图模式的精准匹配,进一步增强识别的鲁棒性。仿真结果表明,该方法能够有效提取MQAM和MPSK信号的特征,并在各调制格式的最佳信噪比范围内实现93%以上的识别准确率,成功区分8PSK、16PSK、16QAM、32QAM、64QAM、128QAM和256QAM等7种调制格式。展开更多
In this paper, we present a detailed comparison of applying three advanced modulation formats including carrierless amplitude and phase modulation(CAP), orthogonal frequency division multiplexing(OFDM), and discrete F...In this paper, we present a detailed comparison of applying three advanced modulation formats including carrierless amplitude and phase modulation(CAP), orthogonal frequency division multiplexing(OFDM), and discrete Fourier transform spread orthogonal frequency division multiplexing(DFT-S OFDM) in underwater visible light communication(UVLC) systems. Cascaded post-equalization schemes are suggested to compensate the system impairments. For the first time, a two-level post-equalizer is presented to mitigate the nonlinear effect and improve the system performance of UVLC. The first post-equalization is based on a novel recursive least square Volterra. These modulation formats are all experimentally demonstrated with corresponding digital signal processing(DSP) algorithms. The experimental results show that single carrier modulations including CAP and DFT-S OFDM can outperform OFDM. Our experiment results show that up to 3 Gb/s over a 1.2 m underwater visible light transmission can be achieved by using DFT-S OFDM 64 QAM and CAP-64. The measured bit error rate is well under the hard decision-forward error correction(HD-FEC) threshold of 3.8 × 10^(-3).展开更多
An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing(OFDM) scheme with multiple modulation formats including diferential phase shift keyed(DPSK), diferential qu...An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing(OFDM) scheme with multiple modulation formats including diferential phase shift keyed(DPSK), diferential quadrature phase shift keyed(DQPSK), and non-return-to-zero(NRZ) is proposed. The noise tolerances of different modulation formats are analyzed, and the optimal input power ratio between phase and intensity modulation formats for the best overall receiving performance is investigated under unchanged total input power. Moreover, this scheme can seamlessly coexist with the traditional WDM channel.展开更多
The production mechanism of non-return-to-zero(NRZ),return-to-zero(RZ)and carrier suppressed return-to-zero(CSRZ)was analyzed theoretically in this paper.We compared the transmission performance of CSRZ with RZ and NR...The production mechanism of non-return-to-zero(NRZ),return-to-zero(RZ)and carrier suppressed return-to-zero(CSRZ)was analyzed theoretically in this paper.We compared the transmission performance of CSRZ with RZ and NRZ formats at 10 Gb/s system by numerical simulation.And we simulated the transmission model constructed with Erbium-doped fiber amplifier(EDFA)as the solo amplifier and the chirped fiber Bragg grating(CFBG)as the solo dispersion compensator used in the system.A practical 8x10 Gb/s 2560 km transmitted experiment was conducted in straight line with these different modulation formats mentioned above and the experiment results show very good agreement with the result of computer simulation.The CSRZ format is more effective than other formats in the system,and involved only 2.5 dB power penalty cost in the practical 2560 km error-free experiment.The results also show that CSRZ will help to optimize the transmitted results and reduce the transmitted penalty further.展开更多
The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the ...The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the result of different telecom operators＇ optical networks convergence. In this case a necessity to transmit differently modulated signals over a single optical fiber even with different bit rates may occur. This research is performed with OptSim 5.2 simulation software that numerically solves nonlinear SchrOdinger equation. The authors have revealed the optimal parameter configuration for developed combined transmission systems and obtained in system＇s channels detected signals bit-error-rate （BER） correlation diagrams. They represent BER as a function from different system＇s parameters such as channel output power level, optical amplifier fixed output power level and system＇s channels allotment in C-band of ITU-T （Telecommunication Standardization Sector of the International Telecommunications Union） recommended spectral grid. As well as these obtained BER values were compared with the results for similar system, where instead of standard single mode fiber （according ITU-T Rec. G.652 D） optical signals are transmitted over non-zero dispersion shifted fiber （ITU-T Rec. G. 655）.展开更多
针对可见光通信信号在传输中易受信道环境和背景噪声干扰等因素影响调制格式识别精度的问题,提出一种用于可见光通信信号调制格式识别的改进YOLOv5s(You Only Look Once)算法。首先,通过YOLOv5s算法网络输入端引入Mixup数据增强方式,将...针对可见光通信信号在传输中易受信道环境和背景噪声干扰等因素影响调制格式识别精度的问题,提出一种用于可见光通信信号调制格式识别的改进YOLOv5s(You Only Look Once)算法。首先,通过YOLOv5s算法网络输入端引入Mixup数据增强方式,将其与原网络中的Mosaic数据增强方式相结合,提升网络的鲁棒性,并增强算法在不同调制格式信号间的泛化能力;其次,将自适应空间特征融合(ASFF)引入到Neck网络中,充分提取不同层次的特征,提高检测精度。实验结果表明,在混合信噪比条件下,所提改进算法的平均精度均值(mAP)达到了0.903,比原始YOLOv5s算法提升了0.7%,且在信噪比为20 dB时mAP高达0.993。展开更多
前列腺素E2(prostaglandin E2,PGE2)作为体内一种重要的生物活性物质,通过作用于前列腺素E受体(prostaglandin E receptor,EP),参与内环境稳态的维持。PGE2在骨代谢调控中发挥重要作用,在骨重建的过程中,调控成骨细胞介导的骨形成与破...前列腺素E2(prostaglandin E2,PGE2)作为体内一种重要的生物活性物质,通过作用于前列腺素E受体(prostaglandin E receptor,EP),参与内环境稳态的维持。PGE2在骨代谢调控中发挥重要作用,在骨重建的过程中,调控成骨细胞介导的骨形成与破骨细胞介导的骨吸收,维持动态平衡。在骨形成方面,PGE2/EP轴通过神经调控、机械负荷调控、与体内其他细胞分子间的交互作用,促进成骨细胞增殖分化,维持骨稳态。因此,PGE2在以骨量异常为特征的疾病中发挥关键作用,可能是潜在的治疗靶点。本文对近年来PGE2在骨形成中的调控机制进行综述,并总结现有的临床应用。展开更多
基金the financial support from Shanxi Province Science and Technology Department(20201101012,202101060301016)the support from the APRC Grant of the City University of Hong Kong(9380086)+5 种基金the TCFS Grant(GHP/018/20SZ)MRP Grant(MRP/040/21X)from the Innovation and Technology Commission of Hong Kongthe Green Tech Fund(202020164)from the Environment and Ecology Bureau of Hong Kongthe GRF grants(11307621,11316422)from the Research Grants Council of Hong KongGuangdong Major Project of Basic and Applied Basic Research(2019B030302007)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(2019B121205002).
文摘A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs.In this work,we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.This method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovskite film.Furthermore,modification of the NiO_(x)/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization.As a result,a large-area perovskite film possessing larger grains,fewer pinholes,and reduced defects could be achieved.The inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved stability.This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.
基金supported by the National Natural Science Foundation of China(No.61377075)the Tianjin Natural Science Foundation(No.17JCYBJC16600)
文摘An optical modulation format generation scheme based on spectral filtering and frequency-to-time mapping is experimentally demonstrated. Many modulation formats with continuously adjustable duty radio and bit rate can be formed by changing the dispersion of dispersion element and the bandwidth of shaped spectrum in this scheme. In the experiment, non-return-to-zero(NRZ) signal with bit rate of 29.41 Gbit/s and 1/2 duty ratio return-to-zero(RZ) signal with bit rate of 13.51 Gbit/s are obtained. The maximum bit rate of modulation format signal is also analyzed.
基金financially supported by the National Natural Science Foundation of China(No.22209024)Tongcheng R&D Foundation(No.CPCIF-RA-0102)the State Key Laboratory of Advanced Fiber Materials,Donghua University
文摘Achieving industrial-level electrochemical CO_(2)reduction to formate remains a significant challenge due to limitations in catalyst selectivity and interfacial proton management at high current densities.In a recent study,Prof.Guo and colleagues report the development of Turingstructured electrocatalysts,which incorporate reaction-diffusion-inspired topologies to engineer mesoscale surface patterns.This design enables precise modulation of the interfacial microenvironment,enhancing CO_(2)activation and suppressing competing hydrogen evolution.The resulting catalysts achieve efficient and stable CO_(2)-to-formate conversion under industrially relevant conditions,offering a promising strategy for scalable carbon-neutral chemical production.
基金Projects (50971072,51131003) support by the National Natural Science Foundation of ChinaProjects (2011CB606301,2012CB825700) supported by the Ministry of Science and Technology of ChinaProject supported by the Administration of Tsinghua University
文摘118 kinds of Pt-Zr phases were established and investigated by considering various structures. Then the related physical properties, such as structural stability, lattice constants, formation enthalpies, elastic constants and bulk moduli, are obtained by ab initio calculations. Based on the calculated results of formation enthalpies, the ground-state convex hull is derived for the Pt-Zr system. The calculated physical data would provide a basis for further thermodynamic calculations and atomistic simulations. For these Pt-Zr compounds, it is found there are a positive linear correlation between the formation enthalpies and atomic volumes, and a negative linear correlation between the bulk modules and atomic volumes.
文摘为了提升未来弹性光网络的性能,提出了一种基于幅值密度特征的调制格式识别方法。该方法将幅值密度特征作为改进的Mobile Net V2模型的输入,通过特征识别确定调制格式类型,并引入了归一化注意力机制(NAM),实现对传输信号调制格式的精准识别。在28 GBaud正交相移键控(QPSK)、8电平正交幅度调制(8QAM)、16QAM、32QAM、64QAM和128QAM传输系统中验证了该方案的可行性。实验结果表明:每种调制格式在达到100%识别准确率时所需的最低光信噪比(OSNR)均低于其对应的20%前向纠错(FEC)阈值,而且,在较宽的OSNR范围内达到了99.62%的识别准确率;在存在残余色散的光网络中,该方案仍能保持较高的识别性能。
文摘针对现有光通信系统中调制格式识别的准确率问题,提出一种结合网格密度峰值聚类(Grid-Based Density Peaks Clustering Algorithm,GDPC)与点阵拟合模板匹配的识别方法。该方法充分考虑了多进制正交振幅调制(Multiple Quadrature Amplitude Modulation,MQAM)与多进制数字相位调制(Multiple Phase Shift Keying,MPSK)星座图的空间分布特征,并通过改进的聚类与匹配策略提升识别性能。相较于传统密度峰值聚类(Density Peaks Clustering Algorithm,DPC),GDPC采用网格划分策略对数据空间进行离散化,从而优化密度估计过程,提高聚类中心的提取精度。此外,引入最小二乘法进行点阵拟合,通过最小残差准则实现星座图模式的精准匹配,进一步增强识别的鲁棒性。仿真结果表明,该方法能够有效提取MQAM和MPSK信号的特征,并在各调制格式的最佳信噪比范围内实现93%以上的识别准确率,成功区分8PSK、16PSK、16QAM、32QAM、64QAM、128QAM和256QAM等7种调制格式。
基金supported by the National Natural Science Foundation of China(NSFC)(No.61571133)the National Key Research and Development Program of China(No.2017YFB0403603)
文摘In this paper, we present a detailed comparison of applying three advanced modulation formats including carrierless amplitude and phase modulation(CAP), orthogonal frequency division multiplexing(OFDM), and discrete Fourier transform spread orthogonal frequency division multiplexing(DFT-S OFDM) in underwater visible light communication(UVLC) systems. Cascaded post-equalization schemes are suggested to compensate the system impairments. For the first time, a two-level post-equalizer is presented to mitigate the nonlinear effect and improve the system performance of UVLC. The first post-equalization is based on a novel recursive least square Volterra. These modulation formats are all experimentally demonstrated with corresponding digital signal processing(DSP) algorithms. The experimental results show that single carrier modulations including CAP and DFT-S OFDM can outperform OFDM. Our experiment results show that up to 3 Gb/s over a 1.2 m underwater visible light transmission can be achieved by using DFT-S OFDM 64 QAM and CAP-64. The measured bit error rate is well under the hard decision-forward error correction(HD-FEC) threshold of 3.8 × 10^(-3).
基金supported by the National Natural Science Fundation of China(Nos.60932004,61132004,and 61090391)the Program for New Century Excellent Talents in University(No.NCET-10-0520)
文摘An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing(OFDM) scheme with multiple modulation formats including diferential phase shift keyed(DPSK), diferential quadrature phase shift keyed(DQPSK), and non-return-to-zero(NRZ) is proposed. The noise tolerances of different modulation formats are analyzed, and the optimal input power ratio between phase and intensity modulation formats for the best overall receiving performance is investigated under unchanged total input power. Moreover, this scheme can seamlessly coexist with the traditional WDM channel.
基金supported by Hi-Tech Research and Development Program of China(No.2001AA122012)the National Natural Science Foundation of China(Grant No.60337010).
文摘The production mechanism of non-return-to-zero(NRZ),return-to-zero(RZ)and carrier suppressed return-to-zero(CSRZ)was analyzed theoretically in this paper.We compared the transmission performance of CSRZ with RZ and NRZ formats at 10 Gb/s system by numerical simulation.And we simulated the transmission model constructed with Erbium-doped fiber amplifier(EDFA)as the solo amplifier and the chirped fiber Bragg grating(CFBG)as the solo dispersion compensator used in the system.A practical 8x10 Gb/s 2560 km transmitted experiment was conducted in straight line with these different modulation formats mentioned above and the experiment results show very good agreement with the result of computer simulation.The CSRZ format is more effective than other formats in the system,and involved only 2.5 dB power penalty cost in the practical 2560 km error-free experiment.The results also show that CSRZ will help to optimize the transmitted results and reduce the transmitted penalty further.
文摘The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the result of different telecom operators＇ optical networks convergence. In this case a necessity to transmit differently modulated signals over a single optical fiber even with different bit rates may occur. This research is performed with OptSim 5.2 simulation software that numerically solves nonlinear SchrOdinger equation. The authors have revealed the optimal parameter configuration for developed combined transmission systems and obtained in system＇s channels detected signals bit-error-rate （BER） correlation diagrams. They represent BER as a function from different system＇s parameters such as channel output power level, optical amplifier fixed output power level and system＇s channels allotment in C-band of ITU-T （Telecommunication Standardization Sector of the International Telecommunications Union） recommended spectral grid. As well as these obtained BER values were compared with the results for similar system, where instead of standard single mode fiber （according ITU-T Rec. G.652 D） optical signals are transmitted over non-zero dispersion shifted fiber （ITU-T Rec. G. 655）.
文摘针对可见光通信信号在传输中易受信道环境和背景噪声干扰等因素影响调制格式识别精度的问题,提出一种用于可见光通信信号调制格式识别的改进YOLOv5s(You Only Look Once)算法。首先,通过YOLOv5s算法网络输入端引入Mixup数据增强方式,将其与原网络中的Mosaic数据增强方式相结合,提升网络的鲁棒性,并增强算法在不同调制格式信号间的泛化能力;其次,将自适应空间特征融合(ASFF)引入到Neck网络中,充分提取不同层次的特征,提高检测精度。实验结果表明,在混合信噪比条件下,所提改进算法的平均精度均值(mAP)达到了0.903,比原始YOLOv5s算法提升了0.7%,且在信噪比为20 dB时mAP高达0.993。
文摘前列腺素E2(prostaglandin E2,PGE2)作为体内一种重要的生物活性物质,通过作用于前列腺素E受体(prostaglandin E receptor,EP),参与内环境稳态的维持。PGE2在骨代谢调控中发挥重要作用,在骨重建的过程中,调控成骨细胞介导的骨形成与破骨细胞介导的骨吸收,维持动态平衡。在骨形成方面,PGE2/EP轴通过神经调控、机械负荷调控、与体内其他细胞分子间的交互作用,促进成骨细胞增殖分化,维持骨稳态。因此,PGE2在以骨量异常为特征的疾病中发挥关键作用,可能是潜在的治疗靶点。本文对近年来PGE2在骨形成中的调控机制进行综述,并总结现有的临床应用。
