Magneto-optical Disk Material for Improving the Density of Information Storage

This paper introduces the fundamental principle and features ofmagneto-optical storage technol- ogy, and discuses the trend and aseries of key techniques for increasing the data storage density ofmagneto-opti- cal disk. The three ways including MO media, recordingmethod and readout method for increasing the disk ca- pacity havebeen discussed. Moreover, the importance with the exchange-coupledeffect between the magnetic layers and recording domain morphology isemphasized.

Self-erasable dynamic surface patterns via controllable elastic modulus boosting multi-encoded and tamper-proof information storage

Dynamic surface patterns(DSPs)have attracted significant interest in anti-counterfeiting,enabling information to be stored,encrypted and decrypted in response to external stimuli.However,creating dynamic surface patterns,capable of controlling wrinkling time and independently modulating different information in both wrinkled and fluorescent states,remains a tremendous challenge.These limit DSPs to further enhance tamper-proofing capacity and extend the information storage density.Here,a rationally designed patterning strategy based on controllable elastic modulus was demonstrated to fabricate self-erasable dynamic surface patterns(S-DSPs)that increase information storage density.These novel S-DSPs strategically integrated amino co-oligomers(ACOs)with the 9-anthracenemethanol(9-AM)as skin layers,designing a bilayer multi-encoding system which could carry several different types of information with wrinkled and fluorescent patterns.The ACOs with relatively low molecular weight can endow the elastic modulus of skin layers with a wide range of regulation.As a result,the difference between the compressive strain and the critical wrinkle strain in the bilayer system would be precisely modulated by photo-dimerization to form quick-response(minimum<1 min)and self-erasable(3 min–8 days)wrinkled patterns for S-DSPs.Meanwhile,the fluorescence pattern could be independently erased and reprogrammed without affecting the change in the wrinkle pattern under modulus-controlled conditions.Moreover,controllable self-erasure in S-DSPs significantly develops tamper-proof capabilities in a supply chain.This original strategy could provide a new approach to the tamper-proof,high-density,and multi-encoded information storage in the product security or inkless printing.

Light-Responsive Polyblend Films with Reconfigurable Surface Micropatterns as Rewritable Information Storage Media

Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo-sensitive patterning surface on film/substrate wrinkle system based on an azo-containing polyblend.By manipulating the stress field of the bilayer system globally and/or locally upon the stress relaxation triggered by the reversible cis-trans isomerization of the azobenzene,heating/cooling triggered surface wrinkles on the polyblend films could be tailor-made with visible-light-irradiation.Notably,upon selective photo-irradiation,bespoke surface patterns may be cyclically generated or eliminated,allowing these reconfigurable patterned polyblend surfaces to be used as rewritable information storage media for non-ink printing.The as-prepared photo-printed information patterns with high-resolution are shown to be rewritable for multiple cycles and legible for over 90 d in dark ambient conditions.This study not only provides a versatile strategy for flourishing the stimulus-sensitive systems,but also sheds light on the stress relaxation-triggered morphological evolution of the wrinkling polyblend films.

Borophene-based materials for energy,sensors and information storage applications

Borophene,as a rising-star monoelemental two-dimensional(2D)material,has motivated great interest because of its novel properties,such as anisotropic plasmonics,high carrier mobility,mechanical compliance,optical transparency,ultrahigh thermal conductance,and superconductivity.These properties make it an ideal candidate for use in the field of energy,sensors,and information storage.Stimulated by the realization of pioneering experimental works in 2015 and the follow-up synthesis experiments,a series of high-performance borophene-based devices in the fields,including supercapacitors,batteries,hydroelectric generators,humidity sensors,gas sensors,pressure sensors,and memories,have been experimentally reported in recent years,which are beneficial to the transition of borophene-based materials from experimental synthesis to practical application.Therefore,in addition to paying attention to the experimental preparation of borophene,significant efforts are needed to promote the advancement of related applications of borophene.In this review,after providing a brief overview of borophene evolution and synthesis,we mainly summarize the applications of borophene-based materials in energy storage,energy conversion,energy harvesting,sensors,and information storage.Finally,based on the current research status,some rational suggestions and discussions on the issues and challenges in the future research direction are proposed.

Organic photoresponsive materials for information storage:a review

Organic photoresponsive materials can undergo various reversible variations in certain physical and chemical properties,such as optical properties,electrochemical properties,conformation,and conductivity,upon photoirradiation.They have been widely applied in various optoelectronic fields,especially in information storage.We summarize research progress on organic photoresponsive materials for information storage.First,the design strategies and photoswitching mechanisms for various kinds of organic photoresponsive materials,including small organic molecules,metal complexes,polymers,supramolecules,and cholesteric liquid crystals,are systematically summarized.These materials exhibit reversible changes of absorption and/or emission properties in response to different wavelengths of light.Subsequently,the applications of these organic materials in information storage,such as data(re)writing and erasing,encryption and decryption,and anticounterfeiting,are introduced in detail.Finally,the current challenges and future directions in this rapidly growing research field are discussed.The review will provide important guidance on the future works about the design of excellent organic photoresponsive materials for optoelectronic applications.

Holographic storage of three-dimensional image and data using photopolymer and polymer dispersed liquid crystal films

We present holographic storage of three-dimensional（3D） images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.

Multicolor Circularly Polarized Luminescence of a Single-Component System Revealing Multiple Information Encryption

Metal-free materials with multicolor tunable circularly polarized luminescence(CPL)are attractive because of their potential applications in information storage and encryption.Here,we designed two enantiomers composed of chiral dialkyl glutamides and achiral vibration-induced emission(VIE)moiety,which can switch on CPL after a simple gelation process.It is noteworthy that the CPL colors vary in different solvents,and this is attributed to various self-assembly-induced microstructures,in which the VIE moiety is restrained to different degrees.Accordingly,a multidimensional code system composed of a quick response code,a ultraviolet(UV)light-activated color code,and a CPL information figure was constructed.To our satisfaction,the system possesses multiple information-storage functions.The orthogonal anticounterfeiting and CPLenhanced encryption functions also improve the system information encryption ability.In brief,this study provides a practical example of CPL applied to information security and an effective approach to obtain a single-component color-tunable CPL material with multiple information storage and encryption functions as well.

Query Performance Prediction for Information Retrieval Based on Covering Topic Score

We present a statistical method called Covering Topic Score （CTS） to predict query performance for information retrieval. Estimation is based on how well the topic of a user＇s query is covered by documents retrieved from a certain retrieval system. Our approach is conceptually simple and intuitive, and can be easily extended to incorporate features beyond bag- of-words such as phrases and proximity of terms. Experiments demonstrate that CTS significantly correlates with query performance in a variety of TREC test collections, and in particular CTS gains more prediction power benefiting from features of phrases and proximity of terms. We compare CTS with previous state-of-the-art methods for query performance prediction including clarity score and robustness score. Our experimental results show that CTS consistently performs better than, or at least as well as, these other methods. In addition to its high effectiveness, CTS is also shown to have very low computational complexity, meaning that it can be practical for real applications.

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.

Large area patterning of ultra-high thermal-stable structural colors in transparent solids

Printing stable color with a lithography-free and environment-friendly technique is in high demand for applications.We report a facile strategy of ultrafast laser direct writing(ULDW)to produce large-scale embedded structural colors inside transparent solids.The diffraction effect of gratings enables effective generation of structural colors across the entire visible spectrum.The structural colors inside the fused silica glass have been demonstrated to exhibit excellent thermal stability under high temperature up to 1200℃, which promises that the written information can be stable for long time even with unlimited lifetime at room temperature.The structural colors in the applications of coloring,anti-counterfeiting,and information storage are also demonstrated.Our studies indicate that the presented ULDW allows for fabricating large-scale and high thermal-stability structural colors with prospects of three-dimensional patterning,which will find various applications,especially under harsh conditions such as high temperature.

Learning to detect subway arrivals for passengers on a train

The use of traditional positioning technologies, such as GPS and wireless local positioning, rely on un- derlying infrastructure. However, in a subway environment, such positioning systems are not available for the position- ing tasks, such as the detection of the train arrivals for the passengers in the train. An alternative approach is to exploit the contextual information available in the mobile devices of subway riders to detect train arrivals. To this end, we pro- pose to exploit multiple contextual features extracted from the mobile devices of subway riders to precisely detecting train arrivals. Following this line, we first investigate poten- tial contextual features which may be effective to detect train arrivals according to the observations from 3D accelerome- ters and GSM radio. Furthermore, we propose to explore the maximum entropy （MaxEnt） model for training a train ar- rival detector by learning the correlation between contextual features and train arrivals. Finally, we perform extensive ex- periments on several real-world data sets collected from two major subway lines in the Beijing subway system. Experi- mental results validate both the effectiveness and efficiency of the proposed approach.

Location-Based Data Dissemination for Spatial Queries in Wireless Broadcast Environments

Most current research on Location-Based Services （LBSs, for short） assumes point-to-point wireless commu- nication, where the server processes a query and returns the query result to the user via a point-to-point wireless channel. However, LBSs via point-to-point wireless channel suffer from a tremendous amount of tramc and service requests from the user and thereby result in poor performance. In this paper, we present broadcast-based spatial query processing algorithms designed to support k-NN （k-Nearest Neighbor） and range queries via a wireless network. The task of the query processor is to selectively monitor the wireless broadcast channel, when the data items are disseminated by the server, according to their locations. Experiments are conducted to evaluate the performance of the proposed algorithms. Comprehensive experiments illustrate that the presented algorithms are highly scalable and are more efficient than the previous techniques in terms of both access time and energy consumption.

Preparation and photochromic properties of pyrazolones/polyvinyl alcohol composite films

Novel photochromic composite films have been successfully fabricated by dispersing pyrazolone derivative：1,3-Diphenyl-4-（3-chlorobenzal）-5-hydroxypyrazole 4-phenylsemicarbazone（la） into hydrosol of polyvinyl alcohol（PVA）.The microstructure,photochromic behaviors and thermal bleaching properties were investigated by Raman spectroscopy,X-ray powder diffraction（XRD）,field emission scanning electron microscopy（FE-SEM） and ultraviolet-visible absorption spectroscopy（UV-vis）.The results showed that la was not only blended but also well dispersed in the PVA polymer films with a suitable content of chromophore.Upon UV light irradiation,the composite films gradually changed from colorless to yellow and recovered fully to the initial state upon thermal bleaching.The time constants of photochromic reactions were almost the same as those of la observed in their crystalline state,indicating that the photochromic phenomenon is barely disturbed by the polymer matrix.