Wavelength selective switch(WSS)is the crucial component in the reconfigurable optical add/drop multiplexer(ROADM),which plays a pivotal role in the next-generation all-optical networks.We present a compact architectu...Wavelength selective switch(WSS)is the crucial component in the reconfigurable optical add/drop multiplexer(ROADM),which plays a pivotal role in the next-generation all-optical networks.We present a compact architecture of twin 1×40 liquid crystal on silicon(LCoS)-based WSS,which can be regarded as a 4f system in the wavelength direction and a 2f system in the switching direction.It is designed with theoretical analysis and simulation investigation.Polarization multiplexing is employed for two sources of twin WSS by polarization con-version before the common optical path.The WSS system attains a coupling efficacy exceeding 96%for 90%of the ports through simulation optimization.The 3 dB bandwidth can be achieved by more than 44 GHz at a 50 GHz grid for all 120 channels at all deflection ports.This work establishes a solid foundation for developing high-performance WSS with larger port counts.展开更多
同步相量测量单元(phasor measurement unit, PMU)为电网运行监测提供了精准数据,然而通信中断、设备故障等原因导致数据质量问题愈发显著。某工程现场PMU上送主站数据出现功率振荡异常现象,分析发现直接原因是母线电压选取错误,工程现...同步相量测量单元(phasor measurement unit, PMU)为电网运行监测提供了精准数据,然而通信中断、设备故障等原因导致数据质量问题愈发显著。某工程现场PMU上送主站数据出现功率振荡异常现象,分析发现直接原因是母线电压选取错误,工程现场复杂的电网配置使得电压选取面临挑战。基于层次分析法对各电压选取方案的决策效果进行量化评估,综合考虑方案的优劣及适应性,最终推荐在特定场景下使用电压切换装置选取母线电压。该装置通过接入一次设备的刀闸,从而自动选择最佳电压源以保障母线电压随一次设备的运行方式同步切换,保障了PMU数据采集的准确性和一致性,进而提升了PMU数据质量。研究结果为涉及母线电压选取的实际应用场景提供了科学的决策支持,结合当地电网运行状况,为提升数据质量和优化电网监控提供有效方案。展开更多
电控离子交换技术(electrochemically switched ion exchange,ESIX)是将电活性离子交换材料(EXIMs)沉积或涂覆在导电基底上,通过电化学控制导电基底上活性材料氧化还原状态实现目标离子置入与释放,从而实现离子的分离。该技术具有痕量...电控离子交换技术(electrochemically switched ion exchange,ESIX)是将电活性离子交换材料(EXIMs)沉积或涂覆在导电基底上,通过电化学控制导电基底上活性材料氧化还原状态实现目标离子置入与释放,从而实现离子的分离。该技术具有痕量提取、无二次污染、速率可控、高选择性等优点。通过共沉淀法制备Ni Fe Mn LDH,并将其与碳纳米管(CNTs)、聚偏二氟乙烯(PVDF)混合涂覆到石墨板上,制得NiFeMn LDH/CNTs/PVDF膜电极。NiFeMn LDH层板上具有丰富的羟基官能团,可与W(Ⅵ)发生羟基配位;层间的阴离子与W(Ⅵ)进行离子交换,可为W(Ⅵ)提供丰富的活性位点。在ESIX系统中,膜电极对W(Ⅵ)的吸附容量可达122.10 mg·g^(-1),且W(Ⅵ)与Mo(Ⅵ)、Cl^(-)、■分离因子(■)分别为1.25、19.60、35.80,实现了W(Ⅵ)选择性分离。此外,该膜电极具有优异的循环稳定性,为钨的高效分离提供了新的方向。展开更多
在复合功率分流混合动力系统中,通过离合器对功率分流装置与动力部件进行离合和制动,可以进一步提高动力性和经济性。传统湿式离合器为适应商用车大扭矩需求,需增加摩擦片数量和体积,导致成本上升和拖曳损失,而机械式离合器虽体积小、...在复合功率分流混合动力系统中,通过离合器对功率分流装置与动力部件进行离合和制动,可以进一步提高动力性和经济性。传统湿式离合器为适应商用车大扭矩需求,需增加摩擦片数量和体积,导致成本上升和拖曳损失,而机械式离合器虽体积小、承载扭矩大,但在超越过程中产生摩擦损失,无法满足混合动力商用车对可控方向锁止和双向非接触自由的需求。设计了一种多模非接触式可控单向离合器,可实现正向锁止、反向锁止以及双向自由三种模式,承载扭矩大同时避免了拖曳和摩擦损失。对多模非接触式可控单向离合器静态和模式切换过程进行了分析,以提高承载扭矩、减小瞬态冲击和实现轻量设计为目标建立了优化模型,提出融合带精英策略的非支配排序遗传算法(Non-dominated sorting genetic algorithmⅡ,NSGA2)、约束有序加权平均算子(Constrained ordered weighted averaging,COWA)和优劣解距离法(Technique for order preference by similarity to ideal solution,TOPSIS)的多目标优化决策方法,与初始方案相比,承载扭矩提升了23.5%、空转角减少了13.7%、关键部件体积减小了0.5%;搭载混合动力专用变速箱进行了台架试验,验证了设计方法的可行性。研究为大扭矩多模非接触式可控单向离合器的设计提供了参考。展开更多
物联网(Internet of Things,IoT)技术的发展给工业界和日常生活带来便利的同时,海量易受到各种攻击和破坏的IoT设备也降低了分布式拒绝服务(Distributed Denial of Service,DDoS)攻击发起的成本,使被攻击方无法响应正常用户访问.为了在...物联网(Internet of Things,IoT)技术的发展给工业界和日常生活带来便利的同时,海量易受到各种攻击和破坏的IoT设备也降低了分布式拒绝服务(Distributed Denial of Service,DDoS)攻击发起的成本,使被攻击方无法响应正常用户访问.为了在物联网边缘中快速、准确地完成DDoS攻击检测,弥补现有方法资源开销大、不精确的缺陷,本文提出了一种基于轻量化卷积神经网络(Lightweight Convolutional Neural Networks,LCNN)的DDoS检测方法.面向物联网流量特性,方法首先提取包级特征和经冗余分析筛选得到的流级特征.之后设计了低参数和运算量的卷积神经网络LCNN,最后基于变维后的特征,快速检测定位攻击.实验结果表明,方法检测准确率达99.4%.同时LCNN在FPGA中能够以较少的资源消耗,保证在1ms时间内完成对一条流的推理判断.展开更多
Photonic integrated switches that are both space and wavelength selective are a highly promising technology for data-intensive applications as they benefit from multi-dimensional manipulation of optical signals.Howeve...Photonic integrated switches that are both space and wavelength selective are a highly promising technology for data-intensive applications as they benefit from multi-dimensional manipulation of optical signals.However,scaling these switches normally poses stringent challenges such as increased fabrication complexity and control difficulties,due to the growing number of switching elements.In this work,we propose a new type of dilated crosspoint topology,which efficiently handles both space and wavelength selective switching,while reducing the required switching element count by an order of magnitude compared to reported designs.To the best of our knowledge,our design requires the fewest switching elements for an equivalent routing paths number and it fully cancels the first-order in-band crosstalk.We demonstrate such an ultra-compact space-and-wavelength selective switch(SWSS)at a scale of 4×4×4λ on the silicon-on-insulator(SOI)platform.Experimental results reveal that the switch achieves an insertion loss ranging from 2.3 dB to 8.6 dB and crosstalk levels in between−35.3 dB and−59.7 dB.The add-drop microring-resonators(MRRs)are equipped with micro-heaters,exhibiting a rise and fall time of 46μs and 0.33μs,respectively.These performance characteristics highlight the switch’s ultralow element count and crosstalk with low insertion loss,making it a promising candidate for advanced data center applications.展开更多
在配电网中使用智能软开关(Soft Open Point, SOP)可有效改善电能质量、提升新能源消纳水平。目前基于SOP配电系统中的模块化多电平换流器(MMC)广泛采用基于旋转坐标系的电压、电流解耦控制,但该控制方法难以满足三相不对称、线路故障...在配电网中使用智能软开关(Soft Open Point, SOP)可有效改善电能质量、提升新能源消纳水平。目前基于SOP配电系统中的模块化多电平换流器(MMC)广泛采用基于旋转坐标系的电压、电流解耦控制,但该控制方法难以满足三相不对称、线路故障与暂态工况下柔性互联系统对MMC换流器性能的要求,因此针对SOP的运行特点,提出一种基于SOP配电系统的MMC多模态直接控制策略。该策略统一了电流环基准的生成方式,简化了控制策略;通过切换电流环基准来加快多工况下MMC换流器运行模式的切换速度;重新定义了桥臂电压参考的生成方式,优化了MMC换流器的动态性能;通过仿真验证了所提控制策略的可靠性和有效性。展开更多
The ion selectivity of nickel hexacyanoferrate thin film to alkali cations in ESIX (electrochemically switched ion exchange) processes was investigated using molecular dynamics(MD) techniques; water and cation (Na+ an...The ion selectivity of nickel hexacyanoferrate thin film to alkali cations in ESIX (electrochemically switched ion exchange) processes was investigated using molecular dynamics(MD) techniques; water and cation (Na+ and Cs+) intercalation, configuration, and dynamics in reduced nickel hexacyanoferrate structures with different cation combinations were studied and compared with the experimental results. In the simulations, water was represented by an extended simple point-charge(SPC/E) model, and all other atomic interactions were represented by a universal force field(UFF). The potential energies of various cations combination (Cs+ and Na+) in reduced i-NiHCF and 1 mol/L Cs/NaCl mixed solution were obtained. In most cases, the total potential energy of the solid is reduced when water is intercalated into the various reduced NiHCF structures. Combining the solid and the solution simulation results, it is shown that the solid composition of 3Cs+/1Na+ is the stablest structure form (NaCs3Ni4[Fe(CN)6]3) over a range of solution compositions.展开更多
基金This work was supported by ZTE Industry⁃University⁃Institute Coopera⁃tion Funds under Grant No.IA20230614004.
文摘Wavelength selective switch(WSS)is the crucial component in the reconfigurable optical add/drop multiplexer(ROADM),which plays a pivotal role in the next-generation all-optical networks.We present a compact architecture of twin 1×40 liquid crystal on silicon(LCoS)-based WSS,which can be regarded as a 4f system in the wavelength direction and a 2f system in the switching direction.It is designed with theoretical analysis and simulation investigation.Polarization multiplexing is employed for two sources of twin WSS by polarization con-version before the common optical path.The WSS system attains a coupling efficacy exceeding 96%for 90%of the ports through simulation optimization.The 3 dB bandwidth can be achieved by more than 44 GHz at a 50 GHz grid for all 120 channels at all deflection ports.This work establishes a solid foundation for developing high-performance WSS with larger port counts.
文摘同步相量测量单元(phasor measurement unit, PMU)为电网运行监测提供了精准数据,然而通信中断、设备故障等原因导致数据质量问题愈发显著。某工程现场PMU上送主站数据出现功率振荡异常现象,分析发现直接原因是母线电压选取错误,工程现场复杂的电网配置使得电压选取面临挑战。基于层次分析法对各电压选取方案的决策效果进行量化评估,综合考虑方案的优劣及适应性,最终推荐在特定场景下使用电压切换装置选取母线电压。该装置通过接入一次设备的刀闸,从而自动选择最佳电压源以保障母线电压随一次设备的运行方式同步切换,保障了PMU数据采集的准确性和一致性,进而提升了PMU数据质量。研究结果为涉及母线电压选取的实际应用场景提供了科学的决策支持,结合当地电网运行状况,为提升数据质量和优化电网监控提供有效方案。
文摘电控离子交换技术(electrochemically switched ion exchange,ESIX)是将电活性离子交换材料(EXIMs)沉积或涂覆在导电基底上,通过电化学控制导电基底上活性材料氧化还原状态实现目标离子置入与释放,从而实现离子的分离。该技术具有痕量提取、无二次污染、速率可控、高选择性等优点。通过共沉淀法制备Ni Fe Mn LDH,并将其与碳纳米管(CNTs)、聚偏二氟乙烯(PVDF)混合涂覆到石墨板上,制得NiFeMn LDH/CNTs/PVDF膜电极。NiFeMn LDH层板上具有丰富的羟基官能团,可与W(Ⅵ)发生羟基配位;层间的阴离子与W(Ⅵ)进行离子交换,可为W(Ⅵ)提供丰富的活性位点。在ESIX系统中,膜电极对W(Ⅵ)的吸附容量可达122.10 mg·g^(-1),且W(Ⅵ)与Mo(Ⅵ)、Cl^(-)、■分离因子(■)分别为1.25、19.60、35.80,实现了W(Ⅵ)选择性分离。此外,该膜电极具有优异的循环稳定性,为钨的高效分离提供了新的方向。
文摘在复合功率分流混合动力系统中,通过离合器对功率分流装置与动力部件进行离合和制动,可以进一步提高动力性和经济性。传统湿式离合器为适应商用车大扭矩需求,需增加摩擦片数量和体积,导致成本上升和拖曳损失,而机械式离合器虽体积小、承载扭矩大,但在超越过程中产生摩擦损失,无法满足混合动力商用车对可控方向锁止和双向非接触自由的需求。设计了一种多模非接触式可控单向离合器,可实现正向锁止、反向锁止以及双向自由三种模式,承载扭矩大同时避免了拖曳和摩擦损失。对多模非接触式可控单向离合器静态和模式切换过程进行了分析,以提高承载扭矩、减小瞬态冲击和实现轻量设计为目标建立了优化模型,提出融合带精英策略的非支配排序遗传算法(Non-dominated sorting genetic algorithmⅡ,NSGA2)、约束有序加权平均算子(Constrained ordered weighted averaging,COWA)和优劣解距离法(Technique for order preference by similarity to ideal solution,TOPSIS)的多目标优化决策方法,与初始方案相比,承载扭矩提升了23.5%、空转角减少了13.7%、关键部件体积减小了0.5%;搭载混合动力专用变速箱进行了台架试验,验证了设计方法的可行性。研究为大扭矩多模非接触式可控单向离合器的设计提供了参考。
文摘物联网(Internet of Things,IoT)技术的发展给工业界和日常生活带来便利的同时,海量易受到各种攻击和破坏的IoT设备也降低了分布式拒绝服务(Distributed Denial of Service,DDoS)攻击发起的成本,使被攻击方无法响应正常用户访问.为了在物联网边缘中快速、准确地完成DDoS攻击检测,弥补现有方法资源开销大、不精确的缺陷,本文提出了一种基于轻量化卷积神经网络(Lightweight Convolutional Neural Networks,LCNN)的DDoS检测方法.面向物联网流量特性,方法首先提取包级特征和经冗余分析筛选得到的流级特征.之后设计了低参数和运算量的卷积神经网络LCNN,最后基于变维后的特征,快速检测定位攻击.实验结果表明,方法检测准确率达99.4%.同时LCNN在FPGA中能够以较少的资源消耗,保证在1ms时间内完成对一条流的推理判断.
基金Engineering and Physical Sciences Research Council (EP/T028475/1)European Union's Horizon Europe Research and Innovation Program (101070560,101017088)。
文摘Photonic integrated switches that are both space and wavelength selective are a highly promising technology for data-intensive applications as they benefit from multi-dimensional manipulation of optical signals.However,scaling these switches normally poses stringent challenges such as increased fabrication complexity and control difficulties,due to the growing number of switching elements.In this work,we propose a new type of dilated crosspoint topology,which efficiently handles both space and wavelength selective switching,while reducing the required switching element count by an order of magnitude compared to reported designs.To the best of our knowledge,our design requires the fewest switching elements for an equivalent routing paths number and it fully cancels the first-order in-band crosstalk.We demonstrate such an ultra-compact space-and-wavelength selective switch(SWSS)at a scale of 4×4×4λ on the silicon-on-insulator(SOI)platform.Experimental results reveal that the switch achieves an insertion loss ranging from 2.3 dB to 8.6 dB and crosstalk levels in between−35.3 dB and−59.7 dB.The add-drop microring-resonators(MRRs)are equipped with micro-heaters,exhibiting a rise and fall time of 46μs and 0.33μs,respectively.These performance characteristics highlight the switch’s ultralow element count and crosstalk with low insertion loss,making it a promising candidate for advanced data center applications.
文摘在配电网中使用智能软开关(Soft Open Point, SOP)可有效改善电能质量、提升新能源消纳水平。目前基于SOP配电系统中的模块化多电平换流器(MMC)广泛采用基于旋转坐标系的电压、电流解耦控制,但该控制方法难以满足三相不对称、线路故障与暂态工况下柔性互联系统对MMC换流器性能的要求,因此针对SOP的运行特点,提出一种基于SOP配电系统的MMC多模态直接控制策略。该策略统一了电流环基准的生成方式,简化了控制策略;通过切换电流环基准来加快多工况下MMC换流器运行模式的切换速度;重新定义了桥臂电压参考的生成方式,优化了MMC换流器的动态性能;通过仿真验证了所提控制策略的可靠性和有效性。
基金Project (20006011) supported by the National Natural Science Foundation of China Project (20021017) by the Natural Science Foundation of Shanxi Province Project (2004-24) by the Scholarship Council Foundation of Shanxi Province
文摘The ion selectivity of nickel hexacyanoferrate thin film to alkali cations in ESIX (electrochemically switched ion exchange) processes was investigated using molecular dynamics(MD) techniques; water and cation (Na+ and Cs+) intercalation, configuration, and dynamics in reduced nickel hexacyanoferrate structures with different cation combinations were studied and compared with the experimental results. In the simulations, water was represented by an extended simple point-charge(SPC/E) model, and all other atomic interactions were represented by a universal force field(UFF). The potential energies of various cations combination (Cs+ and Na+) in reduced i-NiHCF and 1 mol/L Cs/NaCl mixed solution were obtained. In most cases, the total potential energy of the solid is reduced when water is intercalated into the various reduced NiHCF structures. Combining the solid and the solution simulation results, it is shown that the solid composition of 3Cs+/1Na+ is the stablest structure form (NaCs3Ni4[Fe(CN)6]3) over a range of solution compositions.
