High-resolution imaging of magnetic fields of banknote anti-counterfeiting strip using fiber diamond probe

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.

Luminescence regulation of Sb^(3+)in 0D hybrid metal halides by hydrogen bond network for optical anti-counterfeiting

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.

Identification of a Printed Anti-Counterfeiting Code Based on Feature Guidance Double Pool Attention Networks

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.

RFID Anti-Counterfeiting for Retailing Systems

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.

Water-sensitive multicolor luminescence in lanthanide-organic framework for anti-counterfeiting

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.

Field-Deployable Raman Anti-Counterfeit Screening of Tamiflu Capsules

In an effort to promote the availability of safe and effective drugs, the US Food and Drug Administration is developing spectroscopic methods to assess the quality of drugs in the field. Here we report a rapid screening classification method for Tamiflu (oseltamivir phosphate) capsules using a portable Raman spectrometer to perform screening on three solid oral dosage strengths of Tamiflu, 30 mg, 45 mg and 75 mg. Tamiflu is an antiviral drug that is stockpiled for use in the event of pandemic influenza outbreak. The qualitative classification methods reported were developed using the Raman spectra of intact capsules. The classification algorithms used were able to reliably distinguish the three dosage strengths of Tamiflu. These qualitative models are validated with additional Tamiflu samples from different batches and simulated counterfeits of Tamiflu. The probability that a test sample belongs to each dosage strength class is calculated, and strict class predictions are used to assign each sample to a particular class. The classification methods reported here enable development of user-independent, field-deployable methods for finished drug products and are able to correctly assign 92% of the validation samples using authentic Tamiflu and 100% of the simulated counterfeits.

THE STUDY OF UV-PHOTOCHROMIC ANTI-COUNTERFEIT PAPER

The hydrophilicity, dispersity and minuteness of UV (ultraviolet)-photochromic special function materials and its retention and formation mechanisms in stock were comprehensively studied, and the retention mechanism of UV-photochromic fiber was also studied. In addition, according to the disadvantages of special function materials such as big grain, bad hydrophilicity, expensive price and so on, this paper displays our effects focused on the developing of anti-counterfeit pigments slurry system. Moreover, the properties and anti-counterfeit mechanism of the paper with different special function materials were researched by fluorescent spectrum.

Monitoring of Sweat pH and Dual-Mode Anti-Counterfeiting from Metal-Organic Framework-Based Multifunctional Gel

Monitoring of sweat pH plays important roles in physiological health,nutritional balance,psychological stress,and sports performance.However,the combination of functional MOFs with phosphorescent material to acquire the real-time physiological information,as well as the application of dual mode anti-counterfeiting,has seldom been reported.Herein,we developed multifunctional gel films based on MOFs and phosphorescent dyes which responded to H+ions and the related mechanism was studied in detail.Upon exposure to H+,the composite gel film exhibited decreased fluorescent signal but enhanced room temperature phosphorescence(RTP),which could be utilized for sweat pH sensing through a dual-mode.Moreover,multifunctional gel films exhibited a potential application in information encryption and anti-counterfeiting by designing of stimulus responsive multiple patterns.This research provided a new avenue for portable and non-invasive sweat pH monitoring methods while also offering insights into stimulus-responsive multifunctional materials.

Ultralong Organic Phosphorescence of Triazatruxene Derivatives for Dynamic Data Encryption and Anti-counterfeiting

Comprehensive Summary,Organic luminogens with persistent room temperature phosphorescence(RTP)have drawn tremendous attentions due to their promising potentials in optoelectronic devices,information storage,biological imaging,and anti-counterfeiting.In this work,six triazatruxene-based lumiogens with different peripheral substituents and configurations are synthesized and systematically studied.The results show that their fluorescence quantum yields in solid states range from 15.73%to 37.58%.Dispersing the luminogens as guest into the host(PPh_(3))could turn on the persistent RTP,where PPh_(3)acts as not only a rigid matrix to suppress the non-radiative transitions of the guest,but also provides energy transfer channels to the guest.The maximum phosphorescence efficiency and the longest lifetime could reach 29.35%and 0.99 s in co-crystal films of 6-TAT-CN/PPh_(3)and 5-TAT-H/PPh_(3),respectively.Moreover,these host-guest co-crystalline films exhibit great potentials in advanced dynamic data encryption and anti-counterfeiting.This work deepens the insight for low cost,halogen-free,and facile fabrication of all-organic persistent RTP materials.

Metal halide perovskite nanocrystals with enhanced photoluminescence and stability toward anti-counterfeiting highperformance flexible fibers

As a new type of light-collecting and luminescent material,all-inorganic cesium lead halide CsPbX_(3)(X=Cl,Br,I)perovskite nanocrystals(NCs)are expected to have a wide range of applications in the fields of photovoltaics,optoelectronics,and fluorescence anti-counterfeiting,etc.Therefore,improving the fluorescence performance and stability of CsPbX_(3)perovskite NCs to prompt their applications would promise both fundamental and practical significance for in-depth research in the field of halide perovskites.In this paper,we developed a modification strategy to introduce a halogen source,zinc bromide(ZnBr_(2))in hexane,to CsPbX_(3)perovskite that can be conducted under atmospheric conditions with reduced reaction cost and easier operation.The first work in this paper was to apply the modification strategy to CsPbI_(3)nanowires(NWs).Compared with the untreated NWs,the ZnBr_(2)/hexane modified CsPbI_(3)NWs exhibited better fluorescence properties.Subsequently,based on the study of perovskite NWs,we investigated perovskite nanocrystal-CsPbI_(3)nanorods(NRs)with different morphologies and sizes.It was found that the luminescence properties of nanorods(NRs)were superior.Later,we infiltrated the modified NRs into the aramid/polyphenylene sulfide(ACFs/PPS)composite paper yielded from our previous work to study its fluorescence performance for anti-counterfeiting.Their luminescence properties under ultraviolet light irradiation enable better performance in fluorescence anti-counterfeiting.The ZnBr_(2)/hexane modification strategy and the applications studied in this work will expand the scope of perovskite research,laying the foundation for the applications of fluorescent anti-counterfeiting,nano-photoelectric devices,and fluorescent composite materials.

Excitation-wavelength-dependent fluorescent organohydrogel for dynamic information anti-counterfeiting

Anti-counterfeiting labels with various fluorescent colors are of great importance in information encryption-decryption,but are still limited to static information display.Therefore,it is urgent to develop new materials and encryption-decryption logic for improving the security level of secret information.In this study,an organohydrogel made up of poly(N,N-dimethylacrylamide)(pDMA)hydrogel network and polyoctadecyl methacrylate(pSMA)organogel network that copolymerized with two fluorophores,6-acrylamidopicolinic acid moieties(6APA,fluorescent ligand)and spiropyran units(SPMA,photochromic monomer),was prepared by a two-step interpenetrating method.As UV light of 365nm and 254nm can both cleave C_(spiro)-O bonds of SPMA,and the green fluorescence of 6APA-Tb^(3+) can only be excited by 254nm light,the organohydrogel displays yellow and red under the irradiation of 254nm and 365 nm,respectively.In addition to wavelength selectivity,these two fluorophores are thermal-responsive,leading to the fluorescence variation of the organohydrogel during heating process.As a result,secret information loaded on the organohydrogel can be decrypted by the irradiation of UV light,and the authenticity of the information can be further identified by thermal stimulation.Our fluorescent organohydrogel can act as an effective anti-counterfeiting label to improve the information security and protect the information from being cracked.

Lignin-derived dual-function red light carbon dots for hypochlorite detection and anti-counterfeiting

The efficient utilization of natural lignin,which is the main by-product of the cellulose industry,is crucial for enhancing its economic value,alleviating the environmental burden,and improving ecological security.By taking advantage of the large sp2 hybrid domain of lignin and introducing amino functional groups,new lignin-derived carbon dots(SPN-CDs)with red fluorescence were successfully synthesized.Compared with green and blue fluorescent materials,red SPN-CDs have desirable anti-interference properties of short-wave background and exhibit superior luminescence stability.The SPN-CDs obtained exhibited sensitive and distinctive visible color with fluorescence-dual responses toward hypochlorite.Considering this feature,a portable,low-cost,and sensitive fluorescence sensing paper with a low limit of detection of 0.249μmol∙L^(–1) was fabricated using the SPN-CDs for hypochlorite detection.Furthermore,a new type of visible-light and fluorescence dual-channel information encryption platform was constructed.Low-concentration hypochlorite can be employed as an accessible and efficient information encryption/decryption stimulus,as well as an information“eraser”,facilitating a safe and diversified transmission and convenient decryption of information.This work opens new avenues for high-value-added applications of lignin-based fluorescent materials.

Sustainable curcumin-based smart tough fluorescent hydrogels for anti-counterfeiting applications

There is currently great interest in developing an environment-friendly,low-cost,and scalable approach for producing stimuli-responsive fluorescent hydrogels(FHs)with excellent mechanical property,rewritable fluorescence,and dual anti-counterfeiting capabilities.Herein,by applying natural,environment-friendly,and sustainable curcumin as a responsive agent,tough pH-responsive FHs(pH-FHs)are fabricated via a facile preparation strategy.These materials have outstanding mechanical performances:ultimate stress of 180 kPa,an ultimate strain of~2500%,and good anti-fatigue performances against compression.These pH-FHs are able to sense ammonia and formaldehyde gas,resulting in both a color change and fluorescence for dual anti-counterfeiting functionality.This sensing information is stored individually by the pH-FHs and could be externally removed using formaldehyde gas to achieve a rewritable system.Our study provides valuable insights that are expected to facilitate the development of smart FHs for information encryption and anti-counterfeiting applications.

纸张数字化图像处理与信息识别系统设计研究

针对纸张信息识别领域的图像处理技术进行研究,可构建出一种纸张数字化图像处理与信息识别的系统,具体可从软件、硬件两方面对该系统进行分析。将数字化图像处理技术与信息识别两者结合可从纸张中获取有效的防伪信息,并对纸张进行真假辨识,不仅可降低人工误检的现象,还可使检测的工作效率得到提升,而且适合数字化信息管理,同时可降低个人与企业的经济损失,符合现代社会的发展需求,有着重要的现实意义。

Versatile MXene Gels Assisted by Brief and Low‑Strength Centrifugation

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.

酸皮基磷光型碳点的制备及防伪应用

以浸酸山羊皮为碳源、硼酸为硼源,采用热解法制备了磷光型碳点(P-CDs)。探讨了浸酸山羊皮含量、反应pH、反应温度和反应时间对P-CDs余辉时间的影响。采用有机元素分析仪、SEM、EDS、TEM、FTIR、XRD对样品进行了表征,并评价了P-CDs的防伪应用。结果表明,在浸酸山羊皮含量(以3 g硼酸为基准,下同)4.10%、反应pH为7、反应温度为225℃、反应时间为7.5 h的条件下,制备的P-CDs的余辉时间达到12s;该材料的最佳发射波长为520 nm,对应明亮的青绿色余辉。P-CDs平均粒径为4.42 nm,具有典型的石墨结构,硼原子成功地掺入到碳点中,形成了C—B、B—O等共轭链结构,稳定了三重激发态,延长了余辉时间。

基于光充能的多重荧光安全防伪织物的研究

SrS∶Eu,Sm具有红外响应频带宽、效率高等特点,是一种理想的上转换荧光防伪材料。以高温固相法和共沉淀法规模化制备出SrS∶Eu,Sm和NaYF4∶Yb,Er上转换荧光粉(SrS-NaYF4UCPs),通过共混后丝网印刷得到具有多波段、宽频带响应的安全防伪织物,织物经过日光下充能后在980nm激发光下印刷图案会逐渐变色发光,在850nm红外摄像头及智能手机红外镜头下可响应发光。通过扫描电子显微镜、X射线衍射仪和荧光光谱仪等多种表征手法,对所制备荧光粉结构、形貌以及发光性能进行了表征,证明了该织物在防伪、防偷拍领域广阔的应用前景。

Mg_(3)Y_(2)Ge_(3)O_(12)∶Pr^(3+)材料的多色发光及余辉性能

采用高温固相法制备了一种具有颜色变化的长余辉发光材料Mg_(3)Y_(2)Ge_(3)O_(12)∶Pr^(3+)。通过X射线衍射、激发发射光谱、余辉衰减及热释光曲线等,对样品的结构、发光及余辉性能进行了系统分析。在283 nm激发下,发射光谱在485 nm和609 nm处表现出两个较强的尖峰发射,分别归属于Pr^(3+)离子的^(3)P_(2)→^(3)H_(4)及^(3)P_(0)→3H6能级跃迁。通过对Pr^(3+)离子浓度的调控,有效改变了绿光和红光的相对发射强度,从而实现了发光颜色的多色化。此外,在激发光源停止后该材料同样具有多色的余辉发射,对于最佳样品(Mg_(3)Y_(2)Ge_(3)O_(12)∶0.015Pr^(3+))的余辉时间可达1200 s以上。之后,我们通过热释光曲线具体研究了陷阱的分布及余辉的充放能过程。结果表明,Mg_(3)Y_(2)Ge_(3)O_(12)∶0.015Pr^(3+)材料中浅陷阱的浓度相对较低从而导致室温下的余辉性能较弱。由于材料在高温区域具有超宽带陷阱分布,因此,我们进一步探究了其在高温下的多色长余辉性能。在本工作中,我们成功制备了一种单一离子激活的发光及余辉颜色可调的长余辉发光材料,考虑到其在室温以及高温条件下都具有发光及余辉颜色变化的特点,该材料在高温预警标识以及防伪领域有着潜在的应用价值。

用于信息存储与防伪的动态荧光防冻水凝胶

目的 为了提高水凝胶在恶劣环境下的适应能力,探究在信息存储与防伪中的应用前景,本次研究制备一种荧光聚合物水凝胶,提高水凝胶的机械稳定性、保湿性、多环境稳定特性,以及实现将代码信息隐藏在水凝胶内部的测试。方法 在70℃下将羧甲基纤维素钠(CMC)溶于水/二甲基亚砜(DMSO)体系,并在此基础上添加丙烯酸、丙烯酰胺、丙烯酸-2甲氧基乙酯等,用荧光溶液书写特定图案,最后将混合溶液进行紫外光固化,宏观上利用万能试验拉伸机、差式扫描量热仪对其进行力学与防冻性能表征;在微观上使用傅里叶红外光谱、扫描电子显微镜对其内部物质与形貌特征进行描述。结果 结果表明,水/DMSO体系可以提高低温下凝胶的力学性能;其次,制备得到的透明水凝胶在水浸泡下会出现溶胀现象,然后在DMSO溶液中恢复透明,利用这一现象可以实现荧光信息的隐藏与加密。结论 利用水凝胶在不良溶剂中的微相分离和有机溶剂中的溶胀现象,将荧光图案隐藏在其中,溶胀时紫外光下不显示信息,待恢复透明时信息可见,使其在信息加密领域具有广阔的应用前景。

基于区块链的芝麻油防伪溯源系统的设计与实现

芝麻油作为日常饮食中不可或缺的食用油之一,其质量和安全性受到了广泛关注。然而,芝麻油掺假问题日益严重,这使得保障芝麻油的质量安全成为了一个急需解决的问题,所以建立芝麻油防伪溯源对保障质量安全十分重要。本实验设计研发了一套基于区块链技术的芝麻油防伪溯源系统,提出了“区块链缓存”的双存储设计,即链下存储并缓存溯源信息,链上同步存储溯源信息的哈希值;此外还设计了链码直连状态数据库的查询方案,解决了区块链网络数据存储压力大、查询效率低的问题。通过分析与验证,消费者利用微信扫码通过小程序能够快速方便地查验芝麻油真伪,有效解决了芝麻油溯源链不同环节之间在数据安全和溯源信息真实性上的问题,在实践中也取得了较好的应用效果。