Pixelated non-volatile programmable photonic integrated circuits with 20-level intermediate states

Multi-level programmable photonic integrated circuits(PICs)and optical metasurfaces have gained widespread attention in many fields,such as neuromorphic photonics,opticalcommunications,and quantum information.In this paper,we propose pixelated programmable Si_(3)N_(4)PICs with record-high 20-level intermediate states at 785 nm wavelength.Such flexibility in phase or amplitude modulation is achieved by a programmable Sb_(2)S_(3)matrix,the footprint of whose elements can be as small as 1.2μm,limited only by the optical diffraction limit of anin-house developed pulsed laser writing system.We believe our work lays the foundation for laser-writing ultra-high-level(20 levels and even more)programmable photonic systems and metasurfaces based on phase change materials,which could catalyze diverse applications such as programmable neuromorphic photonics,biosensing,optical computing,photonic quantum computing,and reconfigurable metasurfaces.

Strategies for Video Producers to Tell Their Good Stories Under the 5W Model of Communication

In recent years,with the rise of video media such as YouTube and Tik Tok,the short video creation industry has emerged.How to spread China's excellent culture and how to“tell a good Chinese story”have become a hot concern.Using the 5W Model of Communication as a framework for analysis,this paper selects Chinese short videos with high popularity on YouTube as the object of the study.Studies found that the success of these videos was associated with five factors in the process of communication,which are communication main forces,communication content,communication channels,communication audience,and audience effects.Through theoretical and data analysis,the study concluded five strategies in video production to help promote Intercultural communication.

A Causal Configuration Analysis of Payment Decision Drivers in Paid Q&A

Purpose:This paper examines factors of payment decision as well as the role each factor plays in casual configurations leading to high payment intention under systematic and heuristic information processing routes.Design/methodology/approach:Based on heuristic-systematic model(HSM),we propose a configurational analytic framework to investigate complex casual relationships between influencing factors and payment decision.In line with this approach,we use fuzzy-set qualitative comparative analysis(fsQCA)to analyze data crawled from Zhihu.com.Findings:The number of previous consultations is a necessary element in all five equivalent configurations which lead to high intention in payment decision.The heuristic processing route plays a core role while the systematic processing route plays a peripheral role in payment decision-making process.Research limitations:Research is limited in that moderating effect of professional fields has not been considered in the framework.Practical implications:Configurations in results can assist managers of knowledge communities and paid Q&A service providers in the management of information elements to motivate more payment decision.Originality/value:This paper is one of the few studies to apply HSM theory and fsQCA method with respect to the payment decision in paid Q&A.

考虑硬件损耗的可重构智能表面辅助的MIMO通信系统

可重构智能表面技术在实现低功耗、高能效通信的“绿色通信”上具有重要意义,已成为下一代无线通信的关键技术.硬件损耗产生的损耗失真会影响通信系统的性能,本文在可重构智能表面辅助的多输入多输出无线通信系统中考虑硬件损耗,优化目标是最大化系统中用户的加权和速率.由于优化问题的多变量耦合效应,采用块坐标下降算法把原问题解耦成两个子问题,分别对发射预编码矩阵和反射相移矩阵交替优化.仿真结果证明了在波束成形优化中考虑硬件损耗的必要性以及将可重构智能表面引入多输入多输出系统的有效性.

Effect of interstitial carbon and nitrogen on corrosion of FeCoCrNi multi-principal element alloys made by selective laser melting

The corrosion behaviors of selective laser melted(SLMed)FeCoCrNi multi-principal element alloys(MPEAs)with carbon or nitrogen addition in 0.5 M H_(2)SO_(4) solution were investigated.Both C and N ad-dition refined the grains and introduced a heterogeneous structure in SLMed FeCoCrNi MPEA,but they had opposite effects on the corrosion behavior.The doped carbon participated as nano-sized carbides in SLMed MPEA,and localized galvanic corrosion occurred,degrading the corrosion resistance.The doped nitrogen was gathered with chromium and formed CrN chemical clusters in SLMed MPEA,and a protec-tive passive film with a higher Cr_(2)O_(3)/Cr(OH)_(3) ratio formed,which improved corrosion resistance.

Fluorene pendant-functionalization of poly(N-vinylcarbazole)as deep-blue fluorescent and host materials for polymer light-emitting diodes

π-Electron coupling of pendant conjugated segment inπ-stacked semiconducting polymers always causes the formation of defect trapped sites and further quenched high-band excitons,which is harmful to the performance and stability of deep-blue polymer light-emitting diodes(PLEDs).Herein,considerate of“defect”carbazole(Cz)electromers in poly(N-vinylcarbazole)(PVK),a series of fluorene units are introduced into pendant segments(PVCz-DMeF,PVCz-FMeNPh and PVCz-DFMeNPh)to suppress the strongπ-electron coupling of pendant Cz units and enhance radiative transition toward fabricating sable PLEDs.Compared to PVCz-FMeNPh and PVCz-DFMeNPh,PVCz-DMeF spin-coated films show a relatively efficient deep-blue emission,completely similar to its single pendant chromophore,confirmed an extremely weak charge-transfer and electron coupling between adjacent pendant segments.Therefore,PLEDs based on PVCz-DMeF present stable and deep-blue emission with a high color purity(0.17,0.08),associated with extremely weak defect emission at 600∼700nm(induced by carbazole electromers).Finally,PLEDs based on PVCz-DMeF/F8BT blended films(1:1)also present the high maximum luminance(Lmax)of 6261 cd/m2 and current efficiency(CE_(max))of 2.03 cd/A,confirmed slightly trapped sites formation.Therefore,precisely control the arrangement and packing model of pendant units inπ-stacked polymer is an essential prerequisite for building efficient and stable emitter for optoelectronic devices.

Distributed Intelligent Reflecting Surfaces-Aided Device-to-Device Communications System

Intelligent reflecting surface(IRS)is a revolutionizing and promising technology to improve the high transmission rate of the wireless communication systems.Specifically,an IRS consists of a great amount of low-cost passive reflecting elements,which reflect the incident signals to the desired user by collaboratively using passive beamforming.This paper introduces IRSs into a device-to-device(D2D)underlying cellular system to enhance transmission rate performance of the D2D pairs.We formulate an optimization problem of maximizing the transmission rate of the D2D pairs while satisfying the minimum required rate of the cellular users.We address this problem by jointly optimizing the reuse indicator,received beamforming,power allocation,and phase shift matrices.Block coordinate descent(BCD)algorithm is adopted to decouple the original problem into four subproblems.Closed form solutions are obtained by solving the sub-problems of optimizing the received beamforming and power allocation.Then,Kuhn-Munkres(KM)algorithm and minimization-majorization(MM)algorithm are adopted to solve the sub-problems of optimizing the reuse indicator and phase shift matrices,respectively.Simulation results demonstrate that IRSs can effectively improve the transmission rate of the D2D pairs and our proposed distributed IRSs scheme outperforms the other benchmark schemes.

Reflecting Surface-Aided Device-to-Device Communications System

Intelligent reflecting surface(IRS)is a promising technology for its capability of reflecting the incident signal towards the desired user.IRS can improve the efficiency of wireless communication systems.This paper introduces IRS into a device-to-device(D2D)communications system to improve the throughput of the D2D network.We adopt the block coordinate descent al-gorithm and semidefinite relaxation technique to optimize the beamforming vector,power allocation and phase shift matrix.Simulation results demonstrate that IRS is able to enhance the throughput of the D2D communications system,and the proposed algorithm significantly outper-forms the other benchmark algorithms.

Decoupling of the position and angular errors in laser pointing with a neural network method

In laser-pointing-related applications,when only the centroid of a laser spot is considered,then the position and angular errors of the laser beam are often coupled together.In this study,the decoupling of the position and angular errors is achieved from one single spot image by utilizing a neural network technique.In particular,the successful application of the neural network technique relies on novel experimental procedures,including using an appropriate small-focal-length lens and tilting the detector,to physically enlarge the contrast of different spots.This technique,with the corresponding new system design,may prove to be instructive in the future design of laser-pointing-related systems.