Three-dimensional Data Storage Research Articles

Construction of Virtual Reality Rail Transit Simulation System

In order to enhance the quality of professional technology research and development and personnel training in rail transit, this study constructed a virtual reality rail transit simulation system, including the data input and processing of vehicle driving environment, vehicle structure and station scene data, as well as three-dimensional modeling and data storage. The data is stored in the Internet cloud server, which increases the accessibility and sharing of the data, and the rail transit simulation can be realized by calling the three-dimensional model in the cloud server. This efficient and convenient virtual reality content development tool helps to improve the level of scientific research and development and the quality of talent training in rail transit, it will also be the inevitable trend of the development of rail transit industry in the new era.

Design and optimization of molten salt reactor monitoring system based on digital twin technology

Abstract The nuclear power industry is developing rapidly toward intelligence and scale, the digital twin was combined with the industrial interconnection technology to solve the key problems in the application of the digital twin, such as the three-dimensional model presentation, real-time data docking, and the improvement of intelligence degree. Based on the example of Thorium Molten Salt Reactor-Solid Fuel (TMSR-SF0). Firstly, the three-dimensional twin of nuclear power equipment is constructed and the real-time update of twin data is realized based on the Node-EPICS event driver and Websocket communication protocol; Then, the communication interface with MySQL database is developed to realize the storage and management of data; Finally, the PID control system of molten salt circuit pipeline is integrated with back propagation neural network algorithm, and the efficiency and precision of temperature control system are improved by self-modification of weight. The results show that this system has the functions of three-dimensional display, network communication, data storage, and parameter optimization, and the data update cycle is raised to 100 ms, which can provide a certain reference value for the digital transformation of the nuclear monitoring field.

Enhanced Five-Photon Photoluminescence in Subwavelength AlGaAs Resonators.

Multiphoton processes of absorption photoluminescence have enabled a wide range of applications including three-dimensional microfabrication, data storage, and biological imaging. While the applications of two-photon and three-photon absorption and luminescence have matured considerably, higher-order photoluminescence processes remain more challenging to study due to their lower efficiency, particularly in subwavelength systems. Here, we report the observation of five-photon luminescence from a single subwavelength nanoantenna at room temperature enabled by the Mie resonances. We excite an AlGaAs resonator at around 3.6 μm and observe photoluminescence at around 740 nm. We show that the interplay of the Mie multipolar modes at the subwavelength scale can enhance the efficiency of the five-photon luminescence by at least 4 orders of magnitude, being limited only by sensitivity of our detector. Our work paves the way toward applications of higher-order multiphoton processes at the subwavelength scales enabled by the physics of Mie resonances.

Orthogonal gap-enhanced Raman tags for interference-free and ultrastable surface-enhanced Raman scattering

Abstract Spectral interference from backgrounds is not negligible for surface-enhanced Raman scattering (SERS) tags and often influences the accuracy and reliability of SERS applications. We report the design and synthesis of orthogonal gap-enhanced Raman tags (O-GERTs) by embedding alkyne and deuterium-based reporters in the interior metallic nanogaps of core–shell nanoparticles and explore their signal orthogonality as optical probes against different backgrounds from common substrates and media (e.g., glass and polymer) to related targets (e.g., bacteria, cancer cells, and tissues). Proof-of-concept experiments show that the O-GERT signals in the fingerprint region (200–1800 cm−1) are likely interfered by various backgrounds, leading to difficulty of accurate quantification, while the silent-region (1800–2800 cm−1) signals are completely interference-free. Moreover, O-GERTs show much higher photo and biological stability compared to conventional SERS tags. This work not only demonstrates O-GERTs as universal optical tags for accurate and reliable detection onto various substrates and in complex media, but also opens new opportunities in a variety of frontier applications, such as three-dimensional data storage and security labeling.

Evaluation of Compression Algorithms for 3D Pavement Image Data

A standard interchangeable data format was recently developed through the Transportation Pooled-Fund Study TPF-5(299) to meet different requirements and needs for two- and three-dimensional (2D/3D) pavement image data storage and exchange. Considering pavement images occupy large amounts of storage space, efficient compression algorithms for both 8-bit 2D and higher-bit 3D images become one of the key components for a successful implementation of the standard. Highway agencies and industry vendors exclusively use the Joint Photographic Experts Group (JPEG) or its successor JPEG 2000 standard for 2D image compression, while the compression of 3D 16-bit images remains to be proprietary. The goal of this paper is to evaluate suitable algorithms for compressing 3D pavement images. An overview of the state-of-the-art pavement image data collection technologies was performed, and the relevant image data formats were identified. Subsequently, five compression algorithms suitable for 16-bit image data were selected based on results from a comprehensive survey of the TPF-5(299) technical community. The compressions of several representative field images were implemented and evaluated in terms of the computation efficiency and retaining of image quality. The expected benefits of this study include facilitating standard and efficient pavement image data collection and accelerating the development of consistent pavement condition evaluation.

Optical tape for high capacity three-dimensional optical data storage

In this Letter, a new approach of optical tape for high capacity multilayer data storage is proposed. We show that a length of 5 cm and width of 2 cm of soft and transparent optical tape can be used for two-photon three-dimensional bit data storage. We successfully demonstrate writing and reading of six layers of data storage with a transverse bit separation of 2 μm and an axial separation of 2.5 μm in a tetraphenylethylene-doped photobleaching polymer. The fluorescence intensity is insensitive to the storage depth of the photopolymer matrix. Thus, the optical tape that we put forward in the experiment can help people realize true large data storage in the future, like magnetic tape. This method significantly paves a novel way for solving big data storage problems.

Three-Dimensional Data Storage in the Subsurface Region and Fast Read-Out Technologies for Determining the Mechanical Load History of Components

Abstract In industrial production, the absence of clear component identification and unrecognized component defects can lead to a lack of protection against product piracy and unforeseen faults in machinery and equipment. In this context, data, which are stored directly in the subsurface region of a component ensuring its clear identification, as well as sensitive materials which act as sensors for high loading, can contribute to problem-oriented solutions. For robust, forgery-proof component identification that is inseparably linked to the component, three-dimensional data matrix codes are introduced into the component's subsurface region via a laser-induced local heat treatment. This technology ensures a sufficient data density. By locally tempering the metastable austenitic steel, areas are created where mechanical loads exceeding a defined level cause changes in the microstructure of the heat treated subsurface region. By means of adapting suitable read-out technologies, such as high-resolution eddy-current technology and the harmonic analysis of eddy-current signals, the data and load information stored in the component's subsurface region can be read non-destructively.

Photoinitiation and Inhibition under Monochromatic Green Light for Storage of Colored 3D Images in Holographic Polymer-Dispersed Liquid Crystals.

Holographic photopolymer composites have garnered a great deal of interest in recent decades, not only because of their advantageous light sensitivity but also due to their attractive capabilities of realizing high capacity three-dimensional (3D) data storage that is long-term stable within two-dimensional (2D) thin films. For achieving high performance holographic photopolymer composites, it is of critical importance to implement precisely spatiotemporal control over the photopolymerization kinetics and gelation during holographic recording. Though a monochromatic blue light photoinitibitor has been demonstrated to be useful for improving the holographic performance, it is impractical to be employed for constructing holograms under green light due to the severe restriction of the First Law of Photochemistry, while holography under green light is highly desirable considering the relatively low cost of laser source and high tolerance to ambient vibration for image reconstruction. Herein, we disclose the concurrent photoinitiation and inhibition functions of the rose bengal (RB)/N-phenylglycine (NPG) system upon green light illumination, which result in significant enhancement of the diffraction efficiency of holographic polymer-dispersed liquid crystal (HPDLC) gratings from zero up to 87.6 ± 1.3%, with an augmentation of the RB concentration from 0.06 × 10-3 to 9.41 × 10-3 mol L-1. Interestingly, no detectable variation of the ϕ1/2kp/kt1/2, which reflects the initiation efficiency and kinetic constants, is given when increasing the RB concentration. The radical inhibition by RBH• is believed to account for the greatly improved phase separation and enhanced diffraction efficiency, through shortening the weight-average polymer chain length and subsequently delaying the photopolymerization gelation. The reconstructed colored 3D images that are easily identifiable to the naked eye under white light demonstrate great potential to be applied for advanced anticounterfeiting.

Systematic tuning of segmented magnetic nanowires into three-dimensional arrays of ‘bits’

A method is presented for the preparation of a three-dimensional magnetic data storage material system.

(Invited) Systematic Engineering of Structured Magnetic Nanowire Arrays for Three-Dimensional Data Storage

A preparative strategy is presented towards a three-dimensional magnetic data storage medium based on arrays of parallel, cylindrical metallic nanowires structured along their length. The preparation utilizes porous anodic alumina as an inert template that defines the geometry (cylinder length, diameter and pitch), combined with galvanic deposition of the functional materials inside the pores. We demonstrate that the composition of nickel-cobalt alloys can be tuned systematically at one constant deposition potential, whereby the magnetocrystalline anisotropy can be minimized. The wires then display maximal shape anisotropy. The definition of bits along the 'vertical' direction of each wire is performed either by the introduction of non-magnetic segments or by modulation of the pore diameter. The former strategy is made possible by pulsed electrodeposition from a ternary electrolyte. The latter structure is achieved by combining several anodization steps. We demonstrate the presence of magnetic domain boundaries at such designed pinning points using bulk magnetometry and single-wire imaging techniques. As future read/write elements we embed ultrathin oxide layers at mid-height of the wires by atomic layer deposition, and we demonstrate a measurable magnetoresistance effect of these layers. Figure 1

Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories.

Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices.

Systematic layer-by-layer characterization of multilayers for three-dimensional data storage and logic

Magnetic kink solitons are used as a probe to experimentally measure the layer-by-layer coercivity and interlayer coupling strength of an antiferromagnetically coupled perpendicularly magnetized Co multilayer. The magnetic response is well described by a nearest neighbor Ising macrospin model. By controlling the position of one, two or three solitons in the stack using globally applied magnetic fields, we successfully probe the switching of individual buried layers under different neighboring configurations, allowing us to access individual layer's characteristic parameters. We found the coercivity to increase dramatically up the multilayer, while the interlayer coupling strength decreased slightly. We corroborate these findings with scanning transmission electron microscopy images where a degrading quality of the multilayer is observed. This method provides a very powerful tool to characterize the quality of individual layers in complex multilayers, without the need for depth-sensitive magnetic characterization equipment.

Extremely high brightness from polymer-encapsulated quantum dots for two-photon cellular and deep-tissue imaging.

Materials possessing high two photon absorption (TPA) are highly desirable for a range of fields, such as three-dimensional data storage, TP microscopy (TPM) and photodynamic therapy (PDT). Specifically, for TPM, high TP excitation (TPE) brightness (σ × ϕ, where σ is TPA cross-sections and ϕ is fluorescence quantum yield), excellent photostability and minimal cytotoxicity are highly desirable. However, when TPA materials are transferred to aqueous media through molecule engineering or nanoparticle formulation, they usually suffer from the severely decrease of quantum yield (QY). Here, we report a convenient and efficient method for preparing polymer-encapsulated quantum dots (P-QD). Interestingly, the QY was considerably enhanced from original 0.33 (QDs in THF) to 0.84 (P-QD in water). This dramatic enhancement in QY is mainly from the efficiently blocking nonradiative decay pathway from the surface trap states, according to the fluorescence decay lifetimes analysis. The P-QD exhibits extremely high brightness (σ × ϕ up to 6.2 × 106 GM), high photostability, excellent colloidal stability and minimal cytotoxicity. High quality cellular TP imaging with high signal-to-background ratio (> 100) and tissue imaging with a penetration depth of 2200 μm have been achieved with P-QD as probe.

Research on Construction of Visual Platform of Beijing Power Grid Based on Multi-Technology Fusion

The platform uses three-dimensional data modeling, visual simulation and spatial data storage to make the business of regulation center, operation and maintenance center and marketing and management center of Beijing Power grid implement visualized operation, and load the spatial information data, equipment data and operation data of Beijing power grid into the system platform, and the data is displayed with the form of graphic or image, which not only realizes managing space resource data in real three-dimensional scene, but also make the system operator to know the operation state of the system directly, and makes the control measures more effective. And the paper uses virtual reality technology to establish visual scene of ground to realize integrated visual display of power transformation, power transmission and power distribution, which not only makes the producers, managers and decision makers directly master the situation of production line in power station, but also realizes that producers and managers affiliate decision makers to formulate production plan.

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Cultural heritage documentation importance is recognized and supported at international level, the continuous development of new technology is increasing the pressure to document and preserve digitally. In this paper we briefly review the methods that are commonly used to create digital cultural heritage. The storage solutions have also been reviewed to ensure that the digital content is well preserved. The creation and preservation of digital cultural heritage involves three important aspects: the three-dimensional digitization, data storage and data management.

Reading data stored in the state of metastable defects in silicon using band-band photoluminescence: Proof of concept and physical limits to the data storage density

The state of bistable defects in crystalline silicon such as iron-boron pairs or the boron-oxygen defect can be changed at room temperature. In this letter, we experimentally demonstrate that the chemical state of a group of defects can be changed to represent a bit of information. The state can then be read without direct contact via the intensity of the emitted band-band photoluminescence signal of the group of defects, via their impact on the carrier lifetime. The theoretical limit of the information density is then computed. The information density is shown to be low for two-dimensional storage but significant for three-dimensional data storage. Finally, we compute the maximum storage capacity as a function of the lower limit of the photoluminescence detector sensitivity.

Preparation and Photophysical Properties of Two-Photon Absorption Materials Containing Quinoline Ring as Electron Acceptors

Two-photon absorption materials containing quinoline ring as electron acceptors: 9-ethyl-3-(2-quinolin)viny-carbazole (4) and 9-ethyl-3,6-bis(2-(quinolin)vinyl)–carbazole (5) have been prepared by the Vilsmeier reaction of formylation and Knoevenagel condensation. Their one-photon properties including linear absorption, fluorescence spectra, fluorescence quantum yields and fluorescence decay behaviors and the two-photon fluorescence excited by 120 fs pulse at 800nm Ti: sapphire laser operating at 1 kHz repetition rate were investigated, and two photon absorption cross-section was measured. It was showed that material 5 containing two quinoline rings as electron acceptors exhibited high two-photon absorption activity and the two-photon absorption cross-section (δTPA) was 364×10–50cm4s/photon, which was about as four times as that of material 4 containing one quinoline ring as electron acceptor (δTPA=81×10–50cm4 s/photon); material 5 possessed longer fluorescence lifetime (τ) of 21.4 ns and larger fluorescence quantum yield (Φ) of 0.81 than those of material 4 (τ=10.03 ns, Φ=0.77). Influence of chemical structure on the two-photon absorption was discussed. Based on the optical properties, sample 5 might be a promising candidate material for the application in super-high-density three-dimensional (3D) two-photon data storage and two-photon 3D nano/micro structure fabrication.

Nonlinear two-photon absorption properties induced by femtosecond laser with the f ilms of two novel anthracene derivatives

Two novel anthracene derivatives containing 4-vinylpyridine (FPEA) and 2-vinylpyridine (TPEA) poly(methyl methacrylate) films are prepared on quartz glass substrates. Their nonlinear absorption properties are investigated by using a 120-fs, 800-nm Ti:sapphire femtosecond pulsed laser operating at a 1-kHz repetition rate. The unique nonlinear absorption properties of these new compounds are observed by utilizing a Z-scan system. These two-photon absorption (TPA) properties are proven by the two-photon fluorescence excited at 800 nm. The FPEA and TPEA films have nonlinear TPA coefficients of 0.164 and 0.148 cm/GW and the TPA cross sections of 3.345 × 10-48 and 3.081 × 10-48 cm4·s/photon, respectively. The influence of the chemical structures on the nonlinear TPA properties of the compounds is also discussed. The highly nonlinear TPA activities of the films implied that the new anthracene derivatives are suitable materials with promising applications in super-high-density three-dimensional data storage and nano- or microstructure fabrication.

Vertical 3D NAND Flash Memory Technology

We've developed Bit Cost Scalable (BiCS) flash technology as a three-dimensional memory for the future ultra high density storage devices, which extremely reduces the chip costs by vertically stacking memory arrays with punch and plug process. We've advanced it into Pipe-shaped BiCS flash memory introducing U-shaped NAND string structure, to improve operation window, speed and reliability. 32 G bit test chips with 16 stacked layers by 60nm P-BiCS flash process have been fabricated, and the functionality of Multi-Level-Cell (MLC) operation has been successfully demonstrated. P-BiCS is the most promising candidate of three-dimensional ultra high density data storage memories.

Three-dimensional optical data storage through multi-photon confocal microscopy and imaging

Three dimensional optical data storage is one of the most promising tools to respond to the always growing demand for high data storage capacity. Here, we focused a femtosecond laser source by means of a confocal microscope onto different transparent recording media. The purpose of the study is to probe the capability of the system to independently address different data layers within the storage medium achieving thus three dimensional data storage. We demonstrated the possibility to write superposed independent layers of data due to either multiphoton excitation or to local optical breakdown and the performances observed in the different types of media used are compared.