Luminescent materials with multi-emission features are difficult to be replicated, which are highly desirable for advanced anti-counterfeiting. Here, we report the pioneering synthesis of Mn^(2+)/Yb^(3+)/Er^(3+) tri-d...Luminescent materials with multi-emission features are difficult to be replicated, which are highly desirable for advanced anti-counterfeiting. Here, we report the pioneering synthesis of Mn^(2+)/Yb^(3+)/Er^(3+) tri-doped Cs2Ag0.8Na0.2InCl6 double perovskites (MYE-DP), which exhibit photoluminescence (PL) covering from visible to near-infrared (NIR). The PL colors under excitations of 254 and 365 nm are notably different due to the changed relative emission intensities of self-trapped excitons (STEs) and Mn^(2+) d–d transition. Moreover, under the excitation of a NIR laser, the MYE-DP exhibits upconversion (UC) emissions of Mn^(2+) and Er^(3+). After ceasing the excitation, the long-lived trapped electrons can be thermally released to Mn^(2+) and Er^(3+) ions, resulting in both visible and NIR afterglow. Based on multi-modal emissions of the MYE-DP, we demonstrate a five-level anti-counterfeiting strategy, which significantly increases the anti-counterfeiting security. In addition, this work provides valuable insights into the energy transfer between STEs, Mn^(2+), Ln^(3+), and traps, laying a solid foundation for future development of new lead-free perovskites.展开更多
The Sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIHMHs).However,the emission of Sb^(3+) io...The Sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIHMHs).However,the emission of Sb^(3+) ions in OIHMHs is primarily confined to the low energy region,resulting in yellow or red emissions.To date,there are few reports about green emission of Sb^(3+)-doped OIHMHs.Here,we present a novel approach for regulating the luminescence of Sb^(3+) ions in 0D C_(10)H_(2)_(2)N_(6)InCl_(7)·H_(2)O via hydrogen bond network,in which water molecules act as agents for hydrogen bonding.Sb^(3+)-doped C_(10)H_(2)2N_(6)InCl_(7)·H_(2)O shows a broadband green emission peaking at 540 nm and a high photoluminescence quantum yield(PLQY)of 80%.It is found that the intense green emission stems from the radiative recombination of the self-trapped excitons(STEs).Upon removal of water molecules with heat,C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7) generates yellow emis-sion,attributed to the breaking of the hydrogen bond network and large structural distortions of excited state.Once water molecules are adsorbed by C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7),it can subsequently emit green light.This water-induced reversible emission switching is successfully used for optical security and information encryption.Our findings expand the under-standing of how the local coordination structure influences the photophysical mechanism in Sb^(3+)-doped metal halides and provide a novel method to control the STEs emission.展开更多
Counterfeiting of modern banknotes poses a significant challenge,prompting the use of various preventive measures.One such measure is the magnetic anti-counterfeiting strip.However,due to its inherent weak magnetic pr...Counterfeiting of modern banknotes poses a significant challenge,prompting the use of various preventive measures.One such measure is the magnetic anti-counterfeiting strip.However,due to its inherent weak magnetic properties,visualizing its magnetic distribution has been a longstanding challenge.In this work,we introduce an innovative method by using a fiber optic diamond probe,a highly sensitive quantum sensor designed specifically for detecting extremely weak magnetic fields.We employ this probe to achieve high-resolution imaging of the magnetic fields associated with the RMB 50denomination anti-counterfeiting strip.Additionally,we conduct computer simulations by using COMSOL Multiphysics software to deduce the potential geometric characteristics and material composition of the magnetic region within the anti-counterfeiting strip.The findings and method presented in this study hold broader significance,extending the RMB 50 denomination to various denominations of the Chinese currency and other items that employ magnetic anti-counterfeiting strips.These advances have the potential to significantly improve and promote security measures in order to prevent the banknotes from being counterfeited.展开更多
The authenticity identification of anti-counterfeiting codes based on mobile phone platforms is affected by lighting environment,photographing habits,camera resolution and other factors,resulting in poor collection qu...The authenticity identification of anti-counterfeiting codes based on mobile phone platforms is affected by lighting environment,photographing habits,camera resolution and other factors,resulting in poor collection quality of anti-counterfeiting codes and weak differentiation of anti-counterfeiting codes for high-quality counterfeits.Developing an anticounterfeiting code authentication algorithm based on mobile phones is of great commercial value.Although the existing algorithms developed based on special equipment can effectively identify forged anti-counterfeiting codes,the anti-counterfeiting code identification scheme based on mobile phones is still in its infancy.To address the small differences in texture features,low response speed and excessively large deep learning models used in mobile phone anti-counterfeiting and identification scenarios,we propose a feature-guided double pool attention network(FG-DPANet)to solve the reprinting forgery problem of printing anti-counterfeiting codes.To address the slight differences in texture features in high-quality reprinted anti-counterfeiting codes,we propose a feature guidance algorithm that creatively combines the texture features and the inherent noise feature of the scanner and printer introduced in the reprinting process to identify anti-counterfeiting code authenticity.The introduction of noise features effectively makes up for the small texture difference of high-quality anti-counterfeiting codes.The double pool attention network(DPANet)is a lightweight double pool attention residual network.Under the condition of ensuring detection accuracy,DPANet can simplify the network structure as much as possible,improve the network reasoning speed,and run better on mobile devices with low computing power.We conducted a series of experiments to evaluate the FG-DPANet proposed in this paper.Experimental results show that the proposed FG-DPANet can resist highquality and small-size anti-counterfeiting code reprint forgery.By comparing with the existing algorithm based on texture,it is shown that the proposed method has a higher authentication accuracy.Last but not least,the proposed scheme has been evaluated in the anti-counterfeiting code blurring scene,and the results show that our proposed method can well resist slight blurring of anti-counterfeiting images.展开更多
Based on the understanding that the seismic fault system is a nonlinear complex system,Rundle(1995)introduced the nonlinear threshold system used in meteorology to analyze the ocean-atmosphere interface and the El Ni?...Based on the understanding that the seismic fault system is a nonlinear complex system,Rundle(1995)introduced the nonlinear threshold system used in meteorology to analyze the ocean-atmosphere interface and the El Ni?o Southern Oscillation into the study of seismic activity changes,and then proposed the PI method(Rundle et al.,2000a,b).Wu et al.(2011)modified the Pattern Informatics Method named MPI to extract the ionospheric anomaly by using data from DEMETER satellites which is suitable for 1–3 months short-term prediction.展开更多
The developme nt of high-level an ti-co un terfeiti ng tech niq ues is of great sig nifica nee in econo mics and security issues.However,i ntricate read ing methods are required to obta in multi-level info rmati on st...The developme nt of high-level an ti-co un terfeiti ng tech niq ues is of great sig nifica nee in econo mics and security issues.However,i ntricate read ing methods are required to obta in multi-level info rmati on stored in differe nt colors,which greatly limits the applicati on of an ti-co un terfeit ing tech no logy on sol ving real world problems.Here in,we realize multicolor information anti-counterfeiting under simply external stimulation by utilizing the functional groups and multiple emission centers of lanthanide metal organic framework(Ln-MOFs)to tune luminescence color.Water responsive multicolor luminescence represented by both the tunable color from red to blue within the visible region and high sensitive responsivity has bee n achieved,owing to the in creased nonr adiative decay pathways and enhan ced Eu3+-to-liga nd en ergy back tra nsfer.Remarkably,i nfo rmatio n hidde n in differe nt colors n eeds to be read with a specific water content,which can be used as an en crypti on key to en sure the security of the info rmati on for high-level an ti-co un terfeiti ng.展开更多
Counterfeiting is one of the most serious problems in the consumer market. One promising approach for anti-counterfeiting is to attach a low-cost Radio-frequency Identification (RFID) tag to the product authentication...Counterfeiting is one of the most serious problems in the consumer market. One promising approach for anti-counterfeiting is to attach a low-cost Radio-frequency Identification (RFID) tag to the product authentication. In this paper, we propose an RFID system for detecting counterfeiting products. This RFID system consists of the tag authentication protocol and the database correction protocol. We use the tag authentication protocol for authenticating tags without revealing their sensitive information. This protocol also allows the customer to freely inquire the tag. To prevent the widespread of the counterfeit products, we use the tag status information along with tag identity information. Meanwhile, the database correction protocol guarantees the correctness of the tag status. Our anti-counterfeiting system is the first work considering the seller who plays an important role in the consumer product supply chain. Finally, we show that anti-counterfeiting system is quite secure against counterfeiting and the tag authentication protocol is lightweight enough to be implemented in RFID-based applications.展开更多
人们越来越重视乘车的安全性和舒适性,而乘车舒适性与车辆NVH(Noise Vibration and Harshness,NVH)性能息息相关。车辆的NVH性能正在成为汽车开发过程中的最重要指标,白车身动刚度作为NVH性能关键指标之一,对其进行优化改善是车身开发...人们越来越重视乘车的安全性和舒适性,而乘车舒适性与车辆NVH(Noise Vibration and Harshness,NVH)性能息息相关。车辆的NVH性能正在成为汽车开发过程中的最重要指标,白车身动刚度作为NVH性能关键指标之一,对其进行优化改善是车身开发阶段研究的重要内容,对汽车稳定性、舒适性等具有十分重要的意义。在车身结构设计中,一些关键的安装接附点是向车身传递振动的主要来源。在车身实际开发中,对白车身动刚度的优化往往存在优化方向不明确和优化增重较多的问题,为此,提出基于原点动刚度IPI(Input Point Inertance,IPI)面积灵敏度分析方法。以某SUV车型发动机左悬置接附点Z向动刚度为研究对象,进行有限元仿真分析,并以白车身零件厚度作为变量,建立动刚度灵敏度分析模型,基于IPI面积法,计算出IPI曲线围成面积的零件厚度灵敏度和相对于质量的灵敏度,并根据灵敏度重新设计零件板厚,在车身重量不变的前提下,IPI曲线面积减小,动刚度性能整体提升,计算结果也达到设计的目标值(1/3倍频程),优化效果明显,同时证明了IPI面积灵敏度分析方法是可行有效的。展开更多
Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels wi...Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents.In this work,a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL^(-1) into multifunctional architectures under moderate centrifugation is illustrated.The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological,tribological,electrochemical,infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti_(3)C_(2)T_(x) nanosheets.By adopting a gel with optimized pH value,high lubrication,exceptional specific capacitances(~635 and~408 F g^(-1) at 5 and 100 mV s^(-1),respectively),long-term capacitance retention(~96.7%after 10,000 cycles)and high-precision screen-or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved,thus displaying extensive potential applications in the fields of semi-solid lubrication,control-lable devices,supercapacitors,information encryption and infrared camouflaging.展开更多
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2021YQ32)China Postdoctoral Science Foundation(No.2023M740472)+3 种基金the National Natural Science Foundation of China(Nos.62074019,62174016,and 62375028)Partial support was given by the Taishan Scholars Program of Shandong Province(No.tsqn201909117)Opening Foundation of Hubei Key Laboratory of Photoelectric Materials and Devices(No.PMD202401)the special fund for Science and Technology Innovation Teams of Shanxi Province.
文摘Luminescent materials with multi-emission features are difficult to be replicated, which are highly desirable for advanced anti-counterfeiting. Here, we report the pioneering synthesis of Mn^(2+)/Yb^(3+)/Er^(3+) tri-doped Cs2Ag0.8Na0.2InCl6 double perovskites (MYE-DP), which exhibit photoluminescence (PL) covering from visible to near-infrared (NIR). The PL colors under excitations of 254 and 365 nm are notably different due to the changed relative emission intensities of self-trapped excitons (STEs) and Mn^(2+) d–d transition. Moreover, under the excitation of a NIR laser, the MYE-DP exhibits upconversion (UC) emissions of Mn^(2+) and Er^(3+). After ceasing the excitation, the long-lived trapped electrons can be thermally released to Mn^(2+) and Er^(3+) ions, resulting in both visible and NIR afterglow. Based on multi-modal emissions of the MYE-DP, we demonstrate a five-level anti-counterfeiting strategy, which significantly increases the anti-counterfeiting security. In addition, this work provides valuable insights into the energy transfer between STEs, Mn^(2+), Ln^(3+), and traps, laying a solid foundation for future development of new lead-free perovskites.
基金National Natural Science Foundation of China(11974063)Graduate research innovation project,School of Optoelectronic Engineering,Chongqing University(GDYKC2023002)+1 种基金Fundamental Research Funds for the Central Universities(2022CDJQY-010)The authors extend their appreciation to the Deputyship for Research and Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project no.(IFKSUOR3-073-9).
文摘The Sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIHMHs).However,the emission of Sb^(3+) ions in OIHMHs is primarily confined to the low energy region,resulting in yellow or red emissions.To date,there are few reports about green emission of Sb^(3+)-doped OIHMHs.Here,we present a novel approach for regulating the luminescence of Sb^(3+) ions in 0D C_(10)H_(2)_(2)N_(6)InCl_(7)·H_(2)O via hydrogen bond network,in which water molecules act as agents for hydrogen bonding.Sb^(3+)-doped C_(10)H_(2)2N_(6)InCl_(7)·H_(2)O shows a broadband green emission peaking at 540 nm and a high photoluminescence quantum yield(PLQY)of 80%.It is found that the intense green emission stems from the radiative recombination of the self-trapped excitons(STEs).Upon removal of water molecules with heat,C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7) generates yellow emis-sion,attributed to the breaking of the hydrogen bond network and large structural distortions of excited state.Once water molecules are adsorbed by C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7),it can subsequently emit green light.This water-induced reversible emission switching is successfully used for optical security and information encryption.Our findings expand the under-standing of how the local coordination structure influences the photophysical mechanism in Sb^(3+)-doped metal halides and provide a novel method to control the STEs emission.
基金Project supported by the National Key Research and Development Program of China (Grant No.2021YFB2012600)the Shanghai Aerospace Science and Technology Innovation Fund,China (Grant No.SAST-2022-102)。
文摘Counterfeiting of modern banknotes poses a significant challenge,prompting the use of various preventive measures.One such measure is the magnetic anti-counterfeiting strip.However,due to its inherent weak magnetic properties,visualizing its magnetic distribution has been a longstanding challenge.In this work,we introduce an innovative method by using a fiber optic diamond probe,a highly sensitive quantum sensor designed specifically for detecting extremely weak magnetic fields.We employ this probe to achieve high-resolution imaging of the magnetic fields associated with the RMB 50denomination anti-counterfeiting strip.Additionally,we conduct computer simulations by using COMSOL Multiphysics software to deduce the potential geometric characteristics and material composition of the magnetic region within the anti-counterfeiting strip.The findings and method presented in this study hold broader significance,extending the RMB 50 denomination to various denominations of the Chinese currency and other items that employ magnetic anti-counterfeiting strips.These advances have the potential to significantly improve and promote security measures in order to prevent the banknotes from being counterfeited.
基金This work is supported by Supported by the National Key Research and Development Program of China under Grant No.2020YFF0304902the Science and Technology Research Project of Jiangxi Provincial Department of Education under Grant No.GJJ202511。
文摘The authenticity identification of anti-counterfeiting codes based on mobile phone platforms is affected by lighting environment,photographing habits,camera resolution and other factors,resulting in poor collection quality of anti-counterfeiting codes and weak differentiation of anti-counterfeiting codes for high-quality counterfeits.Developing an anticounterfeiting code authentication algorithm based on mobile phones is of great commercial value.Although the existing algorithms developed based on special equipment can effectively identify forged anti-counterfeiting codes,the anti-counterfeiting code identification scheme based on mobile phones is still in its infancy.To address the small differences in texture features,low response speed and excessively large deep learning models used in mobile phone anti-counterfeiting and identification scenarios,we propose a feature-guided double pool attention network(FG-DPANet)to solve the reprinting forgery problem of printing anti-counterfeiting codes.To address the slight differences in texture features in high-quality reprinted anti-counterfeiting codes,we propose a feature guidance algorithm that creatively combines the texture features and the inherent noise feature of the scanner and printer introduced in the reprinting process to identify anti-counterfeiting code authenticity.The introduction of noise features effectively makes up for the small texture difference of high-quality anti-counterfeiting codes.The double pool attention network(DPANet)is a lightweight double pool attention residual network.Under the condition of ensuring detection accuracy,DPANet can simplify the network structure as much as possible,improve the network reasoning speed,and run better on mobile devices with low computing power.We conducted a series of experiments to evaluate the FG-DPANet proposed in this paper.Experimental results show that the proposed FG-DPANet can resist highquality and small-size anti-counterfeiting code reprint forgery.By comparing with the existing algorithm based on texture,it is shown that the proposed method has a higher authentication accuracy.Last but not least,the proposed scheme has been evaluated in the anti-counterfeiting code blurring scene,and the results show that our proposed method can well resist slight blurring of anti-counterfeiting images.
基金supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U2039207)。
文摘Based on the understanding that the seismic fault system is a nonlinear complex system,Rundle(1995)introduced the nonlinear threshold system used in meteorology to analyze the ocean-atmosphere interface and the El Ni?o Southern Oscillation into the study of seismic activity changes,and then proposed the PI method(Rundle et al.,2000a,b).Wu et al.(2011)modified the Pattern Informatics Method named MPI to extract the ionospheric anomaly by using data from DEMETER satellites which is suitable for 1–3 months short-term prediction.
基金This work was supported by the National Natural Science Foundation of China(Nos.52025131,51632008,51772268,and 61721005)Zhejiang Provincial Natural Science Foundation of China(No.LD18E020001).
文摘The developme nt of high-level an ti-co un terfeiti ng tech niq ues is of great sig nifica nee in econo mics and security issues.However,i ntricate read ing methods are required to obta in multi-level info rmati on stored in differe nt colors,which greatly limits the applicati on of an ti-co un terfeit ing tech no logy on sol ving real world problems.Here in,we realize multicolor information anti-counterfeiting under simply external stimulation by utilizing the functional groups and multiple emission centers of lanthanide metal organic framework(Ln-MOFs)to tune luminescence color.Water responsive multicolor luminescence represented by both the tunable color from red to blue within the visible region and high sensitive responsivity has bee n achieved,owing to the in creased nonr adiative decay pathways and enhan ced Eu3+-to-liga nd en ergy back tra nsfer.Remarkably,i nfo rmatio n hidde n in differe nt colors n eeds to be read with a specific water content,which can be used as an en crypti on key to en sure the security of the info rmati on for high-level an ti-co un terfeiti ng.
文摘Counterfeiting is one of the most serious problems in the consumer market. One promising approach for anti-counterfeiting is to attach a low-cost Radio-frequency Identification (RFID) tag to the product authentication. In this paper, we propose an RFID system for detecting counterfeiting products. This RFID system consists of the tag authentication protocol and the database correction protocol. We use the tag authentication protocol for authenticating tags without revealing their sensitive information. This protocol also allows the customer to freely inquire the tag. To prevent the widespread of the counterfeit products, we use the tag status information along with tag identity information. Meanwhile, the database correction protocol guarantees the correctness of the tag status. Our anti-counterfeiting system is the first work considering the seller who plays an important role in the consumer product supply chain. Finally, we show that anti-counterfeiting system is quite secure against counterfeiting and the tag authentication protocol is lightweight enough to be implemented in RFID-based applications.
文摘人们越来越重视乘车的安全性和舒适性,而乘车舒适性与车辆NVH(Noise Vibration and Harshness,NVH)性能息息相关。车辆的NVH性能正在成为汽车开发过程中的最重要指标,白车身动刚度作为NVH性能关键指标之一,对其进行优化改善是车身开发阶段研究的重要内容,对汽车稳定性、舒适性等具有十分重要的意义。在车身结构设计中,一些关键的安装接附点是向车身传递振动的主要来源。在车身实际开发中,对白车身动刚度的优化往往存在优化方向不明确和优化增重较多的问题,为此,提出基于原点动刚度IPI(Input Point Inertance,IPI)面积灵敏度分析方法。以某SUV车型发动机左悬置接附点Z向动刚度为研究对象,进行有限元仿真分析,并以白车身零件厚度作为变量,建立动刚度灵敏度分析模型,基于IPI面积法,计算出IPI曲线围成面积的零件厚度灵敏度和相对于质量的灵敏度,并根据灵敏度重新设计零件板厚,在车身重量不变的前提下,IPI曲线面积减小,动刚度性能整体提升,计算结果也达到设计的目标值(1/3倍频程),优化效果明显,同时证明了IPI面积灵敏度分析方法是可行有效的。
基金This work is financially supported by the Hundred Talents Program of Chinese Academy of Sciences(E30247YB)the Special Talents Program of Lanzhou Institute of Chemical Physics(E0SX0282)+1 种基金the National Natural Science Foundation of Shandong Province(ZR2022QB190)the Innovative Research Funds of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(E1R06SXM07,E1R06SXM09 and E2R06SXM14).
文摘Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents.In this work,a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL^(-1) into multifunctional architectures under moderate centrifugation is illustrated.The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological,tribological,electrochemical,infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti_(3)C_(2)T_(x) nanosheets.By adopting a gel with optimized pH value,high lubrication,exceptional specific capacitances(~635 and~408 F g^(-1) at 5 and 100 mV s^(-1),respectively),long-term capacitance retention(~96.7%after 10,000 cycles)and high-precision screen-or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved,thus displaying extensive potential applications in the fields of semi-solid lubrication,control-lable devices,supercapacitors,information encryption and infrared camouflaging.
