Wireless Body Area Network (WBAN) is considered to apply to both medical healthcare and entertainment applications. A requirement for each application is different, i.e. high reliability for medical healthcare whereas...Wireless Body Area Network (WBAN) is considered to apply to both medical healthcare and entertainment applications. A requirement for each application is different, i.e. high reliability for medical healthcare whereas high throughput for entertainment application. However, for both applications, low energy consumption is requested. Multiple hops technics have been researching in many fields of wireless system, e.g., ad hod, mobile, ITS etc. and its energy-efficiency is reported to be high. We propose the multiple hops technic for WBAN, however, WBAN is different to another systems, almost sensors forward the vital data packet of another sensors while sensing and generating the data packet of itself. Therefore, according to a packet generation rate of all sensors, probabilities of successful transmission and packet loss because of collision, timeout and overflow, are changed. It means that the vital data is lost and the transmit power is wasted due to packet loss. In order to obtain the highest throughput and save the power, the successful transmission probability is analyzed and the packet generation rate is optimized for multiple hops WBAN that using CSMA/CA based on IEEE802.15.6. The numerical calculation result indicates that the optimized packet generation rate depends on the system model. Moreover, the relation between the system model, the optimized packet generation rate and the throughput is discussed in the paper.展开更多
[Objectives] Columbus and Tsingtao Flower were selected to brew Ale beer, thereby studying the brewing characteristics of high α-acid and high β-acid content hops. [Methods] The content of diacetyl and bitterness in...[Objectives] Columbus and Tsingtao Flower were selected to brew Ale beer, thereby studying the brewing characteristics of high α-acid and high β-acid content hops. [Methods] The content of diacetyl and bitterness in beer were determined by a spectrophotometer at 335 and 275 nm, respectively. With pH=8.2 as the end point of potentiometric titration, the total acid content in beer was calculated by acid-base titration method, and sensory evaluation for beer was conducted. [Results] The results show that α-acid is an important factor affecting the production and reduction rate of diacetyl in beer. The production and reduction rate of diacetyl in high α-acid hops were lower than those in high β-acid hops; iso-α-acid was the main source of bitterness in beer, and high α-acid hops had more significant bitter value than high β-acid hops; and malt acid compounds and fermentation production were the main source of total acid in beer, and high α-acid and high β-acid hops had a little effect on total acid in beer. In sensory evaluation, high α-acid hops were more effective than high β-acid hops in terms of zest of the mouthfeel, foaming retention and alcohol fragrance, while in clarity, high α-acid hops were lower than high β-acid hops. [Conclusions] Therefore, we can draw a conclusion that the brewing characteristics of high α-acid hops are better than those of high β-acid hops.展开更多
Wireless sensor networks are provided with a limited source of power. The lifetime of such networks is an overwhelming matter in most network applications. This lifetime depends strongly on how efficiently such energy...Wireless sensor networks are provided with a limited source of power. The lifetime of such networks is an overwhelming matter in most network applications. This lifetime depends strongly on how efficiently such energy is distributed over the nodes especially during transmitting and receiving data. Each node may route messages to destination nodes either through short hops or long hops. Optimizing the length of these hops may save energy, and therefore extend the lifetime of WSNs. In this paper, we propose a theorem to optimize the hop’s length so to make WSN power consumption minimal. The theorem establishes a simple condition on hop’s length range. Computer simulation when performing such condition on Mica2 sensors and Mica2dot sensors reveals good performance regarding WSNs energy consumption.展开更多
We investigate the interplay between the pseudogap state and d-wave superconductivity in the two-dimensional doped Hubbard model by employing an eight-site cluster dynamical mean-field theory method.By tuning electron...We investigate the interplay between the pseudogap state and d-wave superconductivity in the two-dimensional doped Hubbard model by employing an eight-site cluster dynamical mean-field theory method.By tuning electron hopping parameters,the strong-coupling pseudogap in the two-dimensional Hubbard model can be either enhanced or suppressed in the doped Mott insulator regime.We find that in underdoped cases,the closing of pseudogap leads to a significant enhancement of superconductivity,indicating competition between the two in the underdoped regime.In contrast,at large dopings,suppressing the pseudogap is accompanied by a concurrent decrease in the superconducting transition temperature Tc,which can be attributed to a reduction in antiferromagnetic correlations behind both the pseudogap and superconductivity.We elucidate this evolving relationship between pseudogap and superconductivity across different doping regimes.展开更多
1 It's a sunny afternoon in Juliaca,a city near Lake Titicaca,Peru.Among the thousands of native Quechua people gathering in the town square is a man dressed in black on a black horse.He's dressed in memory of...1 It's a sunny afternoon in Juliaca,a city near Lake Titicaca,Peru.Among the thousands of native Quechua people gathering in the town square is a man dressed in black on a black horse.He's dressed in memory of the country's most respected figure:Túpac AmaruⅡ,a native leader who led a war against the Spanish Empire and became a symbol for the fighting spirits in the Andes.He's also there to rap.From horseback,Cay Sur performs his song about heroes,its hip⁃hop beat pulsing(洋溢)through the crowd.展开更多
The increasing reliance on interconnected Internet of Things(IoT)devices has amplified the demand for robust anonymization strategies to protect device identities and ensure secure communication.However,traditional an...The increasing reliance on interconnected Internet of Things(IoT)devices has amplified the demand for robust anonymization strategies to protect device identities and ensure secure communication.However,traditional anonymization methods for IoT networks often rely on static identity models,making them vulnerable to inference attacks through long-term observation.Moreover,these methods tend to sacrifice data availability to protect privacy,limiting their practicality in real-world applications.To overcome these limitations,we propose a dynamic device identity anonymization framework using Moving Target Defense(MTD)principles implemented via Software-Defined Networking(SDN).In our model,the SDN controller periodically reconfigures the network addresses and routes of IoT devices using a constraint-aware backtracking algorithmthat constructs new virtual topologies under connectivity and performance constraints.This address-hopping scheme introduces continuous unpredictability at the network layer dynamically changing device identifiers,routing paths,and even network topology which thwarts attacker reconnaissance while preserving normal communication.Experimental results demonstrate that our approach significantly reduces device identity exposure and scan success rates for attackers compared to static networks.Moreover,the dynamic schememaintains high data availability and network performance.Under attack conditions it reduced average communication delay by approximately 60% vs.an unprotected network,with minimal overhead on system resources.展开更多
The integration of satellite communication network and cellular network has a great potential to enable ubiquitous connectivity in future communication networks.Among numerous related application scenarios,the direct ...The integration of satellite communication network and cellular network has a great potential to enable ubiquitous connectivity in future communication networks.Among numerous related application scenarios,the direct connection of mobile phone to satellite has attracted increasing attention.However,the spectrum scarcity in the sub-6 GHz band and low spectrum utilization prevents its popularity.To address these problem,in this paper,we propose a dynamic spectrum sharing method for satellite network and cellular network based on beam-hopping.Specifically,we first develop a centralized dynamic spectrum sharing architecture based on beam-hopping,and propose a delay pre-compensation scheme for beam hopping pattern.Then,an optimization problem is formulated to maximize the overall capacity of the integrated network,with considering the service requirements,the fairness between beam positions and mixed co-channel interference,etc.To solve this problem,a polling-based dynamic resource allocation algorithm is proposed.Simulation results confirm that the proposed algorithm can effectively reduce the serious cochannel interference between different beams or different systems,and improve the spectrum utilization rate as well as system capacity.展开更多
End-host address mutation is one of the key network moving target defense mechanisms to defend against reconnaissance.However,frequently changing host addresses increases the transmission de-lay of active sessions,whi...End-host address mutation is one of the key network moving target defense mechanisms to defend against reconnaissance.However,frequently changing host addresses increases the transmission de-lay of active sessions,which may cause serious ram-ifications.In this paper,by leveraging the advanced DPDK technology,we proposed a high-performance MTD gateway framework,called HPMG,which can not only prevent adversaries from reconnaissance ef-fectively,but also retain high-speed data packet pro-cessing capabilities.Firstly,every moving target host is assigned three different IP addresses,called real IP,virtual IP,and external IP,to realize multi-level net-work address architecture.To delay the scanning tech-niques of adversaries,HPMG mutates virtual IP and virtual MAC addresses,and replies with fake host re-sponses.Besides,to be transparent to the end-hosts,HPMG keeps real IP and real MAC unchanged.Fi-nally,we optimized the forwarding and processing performance of the HPMG based on the fast path framework of DPDK.Our theoretical analysis,imple-mentation,and evaluation show that HPMG can effec-tively defend against reconnaissance attacks and de-crease the processing delay caused by address muta-tion.展开更多
To guarantee secure communication against eavesdropping and malicious attack,an artificial noise(AN)-aided frequency-hopping(FH)architecture is adopted in this article.But the inevitable time misalignment between the ...To guarantee secure communication against eavesdropping and malicious attack,an artificial noise(AN)-aided frequency-hopping(FH)architecture is adopted in this article.But the inevitable time misalignment between the received signal and locally reconstructed AN will deteriorate the AN cancellation performance,yielding significant secrecy degradation at the FH receiver.In view of this,first,the AN cancellation performance under time misalignment is evaluated via signal to AN-plus-noise ratio,and the system secrecy is analyzed via secrecy rate.Then,to mitigate the performance degradation raised by time misalignment,the transmitting power allocation scheme for AN and confidential signal(CS)is optimized,and the optimal hopping period is designed.Notably,the obtained conclusions in both the performance evaluation and transmitter optimization sections hold no matter whether the eavesdropper can realize FH synchronization or not.Simulations verify that time misalignment will raise non-negligible performance degradation.Besides,the power ratio of AN to CS should decrease as time misalignment increases,and for perfect time synchronization,the transmitting power of AN and CS should be equivalent.In addition,a longer hopping period is preferred for secrecy enhancement when time misalignment gets exacerbated.展开更多
In this work,we investigate disordered Dirac fermions from the perspective of quantum entanglement,which provides a different angle compared to the ordinary perturbative renormalization group(RG)analysis.We consider D...In this work,we investigate disordered Dirac fermions from the perspective of quantum entanglement,which provides a different angle compared to the ordinary perturbative renormalization group(RG)analysis.We consider Dirac fermions subjected to random hopping and random flux,which respectively fall into the chiral Gaussian orthogonal ensemble(cGOE)and chiral Gaussian unitary ensemble(cGUE)universality classes.Existing studies based on perturbative calculations suggest that both types of randomness are marginal.Here,through numerical simulations of the corresponding lattice models,we find that these two different types of randomness exhibit distinct entanglement features,signaling completely different properties in contrast to the perturbative RG analysis.In particular,although the entropy area-law is generally held for both types of randomness,we identify that the subleading term of the entanglement entropy is enhanced by random flux but not by random hopping.This subleading term is known as the entropic F-function in the clean limit without disorder.Our observations indicate that disordered theories in cGOE and cGUE are essentially different,which recalls careful analysis on the RG calculations.展开更多
The layered van der Waals(vdW)ferroelectric CuInP2S6(CIPS)exhibits unique cation-hopping-driven phenomena that bring about unconventional properties with intriguing mechanisms and hold promise for advanced application...The layered van der Waals(vdW)ferroelectric CuInP2S6(CIPS)exhibits unique cation-hopping-driven phenomena that bring about unconventional properties with intriguing mechanisms and hold promise for advanced applications in nanoelectronics.However,an explicit analysis of its lattice dynamics and vibrational symmetries,pivotal for understanding the material’s peculiar ferroelectric and ferroionic behaviors,remains incomplete.Here,we employ angle-resolved polarized Raman spectroscopy in concert with first-principles calculations to systematically unravel the anisotropic lattice vibrations of CIPS single crystals.By analyzing the polarization-dependent Raman intensities,we determine the symmetry assignments and Raman tensors of all major vibrational modes,revealing good agreement with theoretical predictions.Furthermore,we demonstrate the utility of Raman spectroscopy as a sensitive and non-invasive probe for structural and ferroelectric order evolution by examining temperature-driven phase transitions and thickness-dependent polarization suppression in CIPS.Our findings establish a foundational framework for correlating lattice dynamics with functional properties in CIPS and provide a methodological blueprint for studying other vdW ferroelectrics.展开更多
针对DV-HOP(distance vector hop)算法的定位精度对节点间跳数信息依赖性较强的特点,提出一种基于接收信号强度指示(received signal strength indicator,RSSI)每跳分级和平均跳距修正的DV-HOP改进算法RADV-HOP(RSSI and average hoppin...针对DV-HOP(distance vector hop)算法的定位精度对节点间跳数信息依赖性较强的特点,提出一种基于接收信号强度指示(received signal strength indicator,RSSI)每跳分级和平均跳距修正的DV-HOP改进算法RADV-HOP(RSSI and average hopping distance modifying DV-HOP)。仿真结果表明:在相同的网络环境里,与传统DV-HOP算法相比,RADV-HOP定位算法仅需节点通信芯片带有RSSI指示功能及增加少量的计算和通信开销,不需要额外的硬件开销,将每跳分为3个子级时,归一化定位误差能下降65%;与其他DV-HOP修正算法相比,RADV-HOP算法以相同的通信开销和稍微增加的计算开销使定位误差下降了45%。展开更多
文摘Wireless Body Area Network (WBAN) is considered to apply to both medical healthcare and entertainment applications. A requirement for each application is different, i.e. high reliability for medical healthcare whereas high throughput for entertainment application. However, for both applications, low energy consumption is requested. Multiple hops technics have been researching in many fields of wireless system, e.g., ad hod, mobile, ITS etc. and its energy-efficiency is reported to be high. We propose the multiple hops technic for WBAN, however, WBAN is different to another systems, almost sensors forward the vital data packet of another sensors while sensing and generating the data packet of itself. Therefore, according to a packet generation rate of all sensors, probabilities of successful transmission and packet loss because of collision, timeout and overflow, are changed. It means that the vital data is lost and the transmit power is wasted due to packet loss. In order to obtain the highest throughput and save the power, the successful transmission probability is analyzed and the packet generation rate is optimized for multiple hops WBAN that using CSMA/CA based on IEEE802.15.6. The numerical calculation result indicates that the optimized packet generation rate depends on the system model. Moreover, the relation between the system model, the optimized packet generation rate and the throughput is discussed in the paper.
文摘[Objectives] Columbus and Tsingtao Flower were selected to brew Ale beer, thereby studying the brewing characteristics of high α-acid and high β-acid content hops. [Methods] The content of diacetyl and bitterness in beer were determined by a spectrophotometer at 335 and 275 nm, respectively. With pH=8.2 as the end point of potentiometric titration, the total acid content in beer was calculated by acid-base titration method, and sensory evaluation for beer was conducted. [Results] The results show that α-acid is an important factor affecting the production and reduction rate of diacetyl in beer. The production and reduction rate of diacetyl in high α-acid hops were lower than those in high β-acid hops; iso-α-acid was the main source of bitterness in beer, and high α-acid hops had more significant bitter value than high β-acid hops; and malt acid compounds and fermentation production were the main source of total acid in beer, and high α-acid and high β-acid hops had a little effect on total acid in beer. In sensory evaluation, high α-acid hops were more effective than high β-acid hops in terms of zest of the mouthfeel, foaming retention and alcohol fragrance, while in clarity, high α-acid hops were lower than high β-acid hops. [Conclusions] Therefore, we can draw a conclusion that the brewing characteristics of high α-acid hops are better than those of high β-acid hops.
文摘Wireless sensor networks are provided with a limited source of power. The lifetime of such networks is an overwhelming matter in most network applications. This lifetime depends strongly on how efficiently such energy is distributed over the nodes especially during transmitting and receiving data. Each node may route messages to destination nodes either through short hops or long hops. Optimizing the length of these hops may save energy, and therefore extend the lifetime of WSNs. In this paper, we propose a theorem to optimize the hop’s length so to make WSN power consumption minimal. The theorem establishes a simple condition on hop’s length range. Computer simulation when performing such condition on Mica2 sensors and Mica2dot sensors reveals good performance regarding WSNs energy consumption.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274472,12494594,12494591,and 92165204)National Key Research and Development Program of China(Grant No.2022YFA1402802)+2 种基金Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)Guangdong Fundamental Research Center for Magnetoelectric Physics(Grant No.2024B0303390001)Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2401010)。
文摘We investigate the interplay between the pseudogap state and d-wave superconductivity in the two-dimensional doped Hubbard model by employing an eight-site cluster dynamical mean-field theory method.By tuning electron hopping parameters,the strong-coupling pseudogap in the two-dimensional Hubbard model can be either enhanced or suppressed in the doped Mott insulator regime.We find that in underdoped cases,the closing of pseudogap leads to a significant enhancement of superconductivity,indicating competition between the two in the underdoped regime.In contrast,at large dopings,suppressing the pseudogap is accompanied by a concurrent decrease in the superconducting transition temperature Tc,which can be attributed to a reduction in antiferromagnetic correlations behind both the pseudogap and superconductivity.We elucidate this evolving relationship between pseudogap and superconductivity across different doping regimes.
文摘1 It's a sunny afternoon in Juliaca,a city near Lake Titicaca,Peru.Among the thousands of native Quechua people gathering in the town square is a man dressed in black on a black horse.He's dressed in memory of the country's most respected figure:Túpac AmaruⅡ,a native leader who led a war against the Spanish Empire and became a symbol for the fighting spirits in the Andes.He's also there to rap.From horseback,Cay Sur performs his song about heroes,its hip⁃hop beat pulsing(洋溢)through the crowd.
基金supported by the National Key Research and Development Program of China(Project No.2022YFB3104300).
文摘The increasing reliance on interconnected Internet of Things(IoT)devices has amplified the demand for robust anonymization strategies to protect device identities and ensure secure communication.However,traditional anonymization methods for IoT networks often rely on static identity models,making them vulnerable to inference attacks through long-term observation.Moreover,these methods tend to sacrifice data availability to protect privacy,limiting their practicality in real-world applications.To overcome these limitations,we propose a dynamic device identity anonymization framework using Moving Target Defense(MTD)principles implemented via Software-Defined Networking(SDN).In our model,the SDN controller periodically reconfigures the network addresses and routes of IoT devices using a constraint-aware backtracking algorithmthat constructs new virtual topologies under connectivity and performance constraints.This address-hopping scheme introduces continuous unpredictability at the network layer dynamically changing device identifiers,routing paths,and even network topology which thwarts attacker reconnaissance while preserving normal communication.Experimental results demonstrate that our approach significantly reduces device identity exposure and scan success rates for attackers compared to static networks.Moreover,the dynamic schememaintains high data availability and network performance.Under attack conditions it reduced average communication delay by approximately 60% vs.an unprotected network,with minimal overhead on system resources.
基金supported in part by the National Key Research and Development Program of China under Grant 2018YFA0701601in part by the National Natural Science Foundation of China under Grant 61922049 and Grant 61941104in part by the Tsinghua University-China Mobile Communications Group Company Ltd.,Joint Institute.
文摘The integration of satellite communication network and cellular network has a great potential to enable ubiquitous connectivity in future communication networks.Among numerous related application scenarios,the direct connection of mobile phone to satellite has attracted increasing attention.However,the spectrum scarcity in the sub-6 GHz band and low spectrum utilization prevents its popularity.To address these problem,in this paper,we propose a dynamic spectrum sharing method for satellite network and cellular network based on beam-hopping.Specifically,we first develop a centralized dynamic spectrum sharing architecture based on beam-hopping,and propose a delay pre-compensation scheme for beam hopping pattern.Then,an optimization problem is formulated to maximize the overall capacity of the integrated network,with considering the service requirements,the fairness between beam positions and mixed co-channel interference,etc.To solve this problem,a polling-based dynamic resource allocation algorithm is proposed.Simulation results confirm that the proposed algorithm can effectively reduce the serious cochannel interference between different beams or different systems,and improve the spectrum utilization rate as well as system capacity.
基金supported by National Natural Science Foundation of China(No.61821001)Science and Tech-nology Key Project of Guangdong Province,China(2019B010157001).
文摘End-host address mutation is one of the key network moving target defense mechanisms to defend against reconnaissance.However,frequently changing host addresses increases the transmission de-lay of active sessions,which may cause serious ram-ifications.In this paper,by leveraging the advanced DPDK technology,we proposed a high-performance MTD gateway framework,called HPMG,which can not only prevent adversaries from reconnaissance ef-fectively,but also retain high-speed data packet pro-cessing capabilities.Firstly,every moving target host is assigned three different IP addresses,called real IP,virtual IP,and external IP,to realize multi-level net-work address architecture.To delay the scanning tech-niques of adversaries,HPMG mutates virtual IP and virtual MAC addresses,and replies with fake host re-sponses.Besides,to be transparent to the end-hosts,HPMG keeps real IP and real MAC unchanged.Fi-nally,we optimized the forwarding and processing performance of the HPMG based on the fast path framework of DPDK.Our theoretical analysis,imple-mentation,and evaluation show that HPMG can effec-tively defend against reconnaissance attacks and de-crease the processing delay caused by address muta-tion.
基金supported in part by the National Natural Science Foundation of China under Grant 62071094in part by the National Key Laboratory of Wireless Communications Foundation under Grant IFN202402in part by the Postdoctoral Fellowship Program(Grade C)of China Postdoctoral Science Foundation under Grant GZC20240217.
文摘To guarantee secure communication against eavesdropping and malicious attack,an artificial noise(AN)-aided frequency-hopping(FH)architecture is adopted in this article.But the inevitable time misalignment between the received signal and locally reconstructed AN will deteriorate the AN cancellation performance,yielding significant secrecy degradation at the FH receiver.In view of this,first,the AN cancellation performance under time misalignment is evaluated via signal to AN-plus-noise ratio,and the system secrecy is analyzed via secrecy rate.Then,to mitigate the performance degradation raised by time misalignment,the transmitting power allocation scheme for AN and confidential signal(CS)is optimized,and the optimal hopping period is designed.Notably,the obtained conclusions in both the performance evaluation and transmitter optimization sections hold no matter whether the eavesdropper can realize FH synchronization or not.Simulations verify that time misalignment will raise non-negligible performance degradation.Besides,the power ratio of AN to CS should decrease as time misalignment increases,and for perfect time synchronization,the transmitting power of AN and CS should be equivalent.In addition,a longer hopping period is preferred for secrecy enhancement when time misalignment gets exacerbated.
基金supported by the National Key Research and Development Program(Grant No.2022YFA1402204)the National Natural Science Foundation[Grant Nos.22373095(QL),52471020(WC),and 12474144(WZ)]+2 种基金the Innovation Program for Quantum Science and Technology[Grant No.2021ZD0303306(QL)]the Fundamental Research Funds for the Central Universities[Grant No.JZ2025HGQA0310(WC)]the Science Research Foundation for High-Level Talents of Anhui University of Science and Technology[Grant No.YJ20240002(WL)].
文摘In this work,we investigate disordered Dirac fermions from the perspective of quantum entanglement,which provides a different angle compared to the ordinary perturbative renormalization group(RG)analysis.We consider Dirac fermions subjected to random hopping and random flux,which respectively fall into the chiral Gaussian orthogonal ensemble(cGOE)and chiral Gaussian unitary ensemble(cGUE)universality classes.Existing studies based on perturbative calculations suggest that both types of randomness are marginal.Here,through numerical simulations of the corresponding lattice models,we find that these two different types of randomness exhibit distinct entanglement features,signaling completely different properties in contrast to the perturbative RG analysis.In particular,although the entropy area-law is generally held for both types of randomness,we identify that the subleading term of the entanglement entropy is enhanced by random flux but not by random hopping.This subleading term is known as the entropic F-function in the clean limit without disorder.Our observations indicate that disordered theories in cGOE and cGUE are essentially different,which recalls careful analysis on the RG calculations.
基金supported by the National Natural Science Foundation of China(Grant Nos.12474089,12574102 for L.Y.and L.F.,and 12404102 for J.Z.)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions(for L.Y.and L.F.)+2 种基金the Natural Science Foundation of the Jiangsu Province(Grant No.BK20230806 for J.Z.)Southeast University Interdisciplinary Research Program for Young Scholars(Grant No.2024FGC1008 for J.Z.)the support by the State Key Laboratory of Solid State Microstructures(Nanjing University)(No.M37067)。
文摘The layered van der Waals(vdW)ferroelectric CuInP2S6(CIPS)exhibits unique cation-hopping-driven phenomena that bring about unconventional properties with intriguing mechanisms and hold promise for advanced applications in nanoelectronics.However,an explicit analysis of its lattice dynamics and vibrational symmetries,pivotal for understanding the material’s peculiar ferroelectric and ferroionic behaviors,remains incomplete.Here,we employ angle-resolved polarized Raman spectroscopy in concert with first-principles calculations to systematically unravel the anisotropic lattice vibrations of CIPS single crystals.By analyzing the polarization-dependent Raman intensities,we determine the symmetry assignments and Raman tensors of all major vibrational modes,revealing good agreement with theoretical predictions.Furthermore,we demonstrate the utility of Raman spectroscopy as a sensitive and non-invasive probe for structural and ferroelectric order evolution by examining temperature-driven phase transitions and thickness-dependent polarization suppression in CIPS.Our findings establish a foundational framework for correlating lattice dynamics with functional properties in CIPS and provide a methodological blueprint for studying other vdW ferroelectrics.
文摘针对DV-HOP(distance vector hop)算法的定位精度对节点间跳数信息依赖性较强的特点,提出一种基于接收信号强度指示(received signal strength indicator,RSSI)每跳分级和平均跳距修正的DV-HOP改进算法RADV-HOP(RSSI and average hopping distance modifying DV-HOP)。仿真结果表明:在相同的网络环境里,与传统DV-HOP算法相比,RADV-HOP定位算法仅需节点通信芯片带有RSSI指示功能及增加少量的计算和通信开销,不需要额外的硬件开销,将每跳分为3个子级时,归一化定位误差能下降65%;与其他DV-HOP修正算法相比,RADV-HOP算法以相同的通信开销和稍微增加的计算开销使定位误差下降了45%。