New bistable organic photochromic compounds for bitwise working optical memory

The results of our spectral and kinetic studies for some photochromic compounds (58 diarylethenes and 9 fulgimides) are presented. Aiming at targeted synthesis of new photochromic compounds, the structure-photochromic behavior relationship (SPBR) for the synthesized compounds has been analyzed. The perspectives for application of these compounds in development of recording media for use in optical memory devices are outlined. The text was submitted by the authors in English.     

Modeling laser heated thin film media for heat assisted magnetic recording

In the present study, we concern laser induced heat generation and its effect on lubricant depletion on the multilayer disk structure. A mathematical model is applied to explore the local laser heating from the point of view of the interaction between the disk media and the electromagnetic wave. The absorption rate of optical energy in each layer of disk structure is derived from the Maxwell equations, which is incorporated into the energy equation by a source term. We simulate the unsteady heat transfer and lubricant depletion processes on a multilayer disk structure. The effect of multi-cycle heating on the lubricant depletion is investigated. Comparison between the present results and those obtained by applying a heat flux boundary condition is also made. The present simulations provide useful information on the media structure design of hard disk drives in heat assisted magnetic recording.     

未来存储技术——蛋白质存储

一、引言基于硅材料和无机材料的存储技术正在接近它们的逻辑极限,因此记录密度的提高变得越来越困难。许多研究团队把利用基因工程中的光敏蛋白质来设计存储设备作为研究热点。日本Testuro Majima团队研发了一种用于代替当前的磁记录介质和光存储介质的新型蛋白质存储设备。研究人员利用一种特殊的荧光蛋白质在载玻片上蚀刻或者记录一种特殊模式的     

Readout characteristics of flexible monolithic optical head slider combined with visible laser light guide

Optical near-field recording is a candidate technology for overcoming the diffraction limit of conventional optical recording. In our previous work, we proposed a novel optical head slider for near-field recording that we call a flexible optical head slider. An air-bearing pad pattern is formed on the apex of a cantilever-like polymeric waveguide so that, by using the cantilever itself as the slider suspension, a single body structure incorporates the functions of the flying slider, suspension, and waveguide. This structure can be expected to provide several important advantages by miniaturizing head assemblies; simplifying the assembly and optical trimming processes; and producing a lighter head, thus allowing a wider tracking bandwidth. In this paper, we report the read-out signal evaluation of the flexible optical head slider. Using a slider with a sub-micron sized aperture, read-out of a test metal-patterned ROM (Read Only Memory) disk was successfully demonstrated down to a 0.2 μm linewidth line and space pattern.     

Optical recording media based on nanoparticles for superhigh density information storage

The use of nanoparticles for optical strorage of information is reviewed. Several different optical recording media utilizing the nanoparticles were designed and tested. The main characteristics of the media, namely, density of recording energy needed and density of stored information start from the like ones for blu-ray disk and for the best media are far better.     

A multilayer perceptron solution to the match phase problem inrule-based artificial intelligence systems

In rule-based artificial intelligence (AI) planning, expert, and learning systems, it is often the case that the left-hand-sides of the rules must be repeatedly compared to the contents of some working memory. Normally, the intent is to determine which rules are relevant to the current situation (i.e., to find the conflict set). A technique using a multilayer perceptron to solve the match phase problem for rule-based AI systems is presented. A syntax for premise formulas (i.e., the left-hand-sides of the rules) is defined, and working memory is specified. From this, it is shown how to construct a multilayer perceptron that finds all of the rules which can be executed for the current situation in working memory. The complexity of the constructed multilayer perceptron is derived in terms of the maximum number of nodes and the required number of layers. A method for reducing the number of layers to at most three is presented     

Holographic data storage

Research into and the development of data storage devices is a race to keep up with the continuing demand for more capacity, more density, and faster readout rates. Improvements in conventional memory technologies-magnetic hard disk drives, optical disks, and semiconductor memories-have managed to keep pace with the demand for bigger, faster memories. However, there is strong evidence that these two-dimensional surface storage technologies are approaching fundamental limits. An alternative approach for next-generation memories is to store data in three dimensions. This article describes developments in holographic 3D memories, in which high density is achieved by superimposing many holograms within the same volume of recording material. Holographic storage is a promising candidate for next-generation storage. Research has demonstrated that holographic storage systems with desirable properties can be engineered. The next step is to build these systems at costs competitive with those of existing technologies and to optimize the storage media     

基于光传输网络的多层恢复研究

以WDM为基础的光传输网络在提供高传输容量的同时对网络可靠性也提出了更严格的要求.通过有效的层间协作和控制可以充分利用光传输网络不同层次的原有恢复能力,并对整个网络业务的恢复时间和冗余资源需求有着重要影响.本文提出的多层恢复框架结构对于组织并实施具体的多层恢复方案提供了很有价值的指导意义.     

基于ARM-Linux的嵌入式光学相干层析成像系统的研究

分析了相位对照光学相干层析成像的基本原理,并基于ARM9架构的嵌入式微处理器S3C2440和当前主流嵌入式的Linux多用户操作系统,提出了一套用于无损检测高分子聚合物有机复合材料的相位对照光学相干层析成像系统的设计方案。详细介绍了系统的原理及搭建过程,使用相位对照理论分析方法和表面变形测量方法并通过实验获得高分子聚合物有机复合材料内部结构的分布图。实验结果表明该嵌入式光学相干层成像系统是可行的。     

Design of near-field recording optics using truncated hemispherical SIL with cover-layer incident dual recording layers

In this paper, we propose a novel optics design for media inside near-field recording (NFR) using a truncated hemispherical solid immersion lens (HMS). To obtain strong advantage of data protection and high data capacity simultaneously, a truncated HMS based near field optics with cover-layer incident dual recording layers is designed. In this design, to improve the small optical tolerance of the truncated HMS unit and to adjust dual focusing positions, an additional aspheric lens surface is added on top of the truncated HMS and it is combined with zoom optics composed of two single lenses having a low numerical aperture (NA). Also, to compensate for chromatic aberration, which is a serious problem for optics using a blue laser diode, a diffractive optical element is also designed. Using zoom optics, an additional aspheric lens surface, and a diffractive optical element together, the wavefront aberration and chromatic aberration are effectively reduced in a broad range of cover-layer thicknesses and wavelength variations. In addition, in this paper, the effect of a gap induced aberration is investigated by analyzing the different behavior of each TM and TE wave for the cover-layer incident NFR optics.Paper presented at the 15th Annual Symposium on Information Storage and Processing Systems, Santa Clara, CA, USA, 28–29 June, 2005.     

Optical recording system using an integrated solid immersion lens

 Nobody doubts that the high area density recording and miniaturization of the devices in the data storage are in the general trend. What matters now is how to compact the data in a small area and how to decrease the device size. For the last decade, a lot of researchers engaged in the optical memory have expected the near-field recording (NFR) technology to be able to bring the remarkable results. However, they have been confronted with many obstacles including heat, contamination, dynamics of optical head in the unsealed environment, etc. In this paper, we propose the new concept of a solid immersion lens (SIL) with a potential to be able to resolve the critical issues on the way to the commercialization of the high areal density optical recording using the near-field recording technology. Received: 5 July 2001/Accepted: 17 October 2001     

Memory Trends in the 70's

A modern data storage system is designed in three independent phases. The first design, that of the memory element and subsystem, has the objectives of providing functionally simple storage units of high capacity and operating speed at low cost. This discipline embraces the design of core, film, semiconductor and optical static memories as well as a variety of moving media memories.     

Source cell phone verification from speech recordings using sparse representation

Source recording device recognition is an important emerging research field in digital media forensics. The literature has mainly focused on the source recording device identification problem, whereas few studies have focused on the source recording device verification problem. Sparse representation based classification methods have shown promise for many applications. This paper proposes a source cell phone verification scheme based on sparse representation. It can be further divided into three schemes which utilize exemplar dictionary, unsupervised learned dictionary and supervised learned dictionary respectively. Specifically, the discriminative dictionary learned by supervised learning algorithm, which considers the representational and discriminative power simultaneously compared to the unsupervised learning algorithm, is utilized to further improve the performances of verification systems based on sparse representation. Gaussian supervectors (GSVs) based on MFCCs, which have shown to be effective in capturing the intrinsic characteristics of recording devices, are utilized for constructing and learning dictionary. SCUTPHONE, which is a corpus of speech recordings from 15 cell phones, is presented. Evaluation experiments are conducted on three corpora of speech recordings from cell phones and demonstrate the effectiveness of the proposed methods for cell phone verification. In addition, the influences of number of target examples in the exemplar dictionary and size of the unsupervised learned dictionary on source cell phone verification performance are also analyzed.     

Performance-optimized design of electromagnetic micro-actuator for Probe recording storage device

In this paper the performance-optimized design of an electromagnetic micro-actuator for a Probe data-storage system is described. The Probe recording system considered in this study consists of a MEMS-based recording head array that can translate relative to a Ferroelectric media substrate. The probe device is slated to achieve 1 Tb/in2 recording density and a read/write data rate of 100 Mb/s while operating within a total power budget of 100 mW. Stringent requirements apply to the form-factor and packaging, power consumption, and operating environment making the design of the mechanical architecture and in particular, the actuator a challenging task. A methodology based on an analytical model framework for performance-optimal design of the actuator meeting these constraints is developed and presented.     

A Petrov–Galerkin multilayer discretization to second order elliptic boundary value problems

We study in this paper a multilayer discretization of second order elliptic problems, aimed at providing reliable multilayer discretizations of shallow fluid flow problems with diffusive effects. This discretization is based upon the formulation by transposition of the equations. It is a Petrov–Galerkin discretization in which the trial functions are piecewise constant per horizontal layers, while the test functions are continuous piecewise linear, on a vertically shifted grid.We prove the well posedness and optimal error order estimates for this discretization in natural norms, based upon specific inf–sup conditions.We present some numerical tests with parallel computing of the solution based upon the multilayer structure of the discretization, for academic problems with smooth solutions, with results in full agreement with the theory developed.     

一种测量超声波传播时间的装置

基于超声波技术的检测方法，通常需要精确地测量超声波在介质中的传播时间。针对超声波无损压力检测技术，开发了一种采用回振法测量超声波传播时间的装置。测量时，装置中接收探头检测到的信号通过门电路输出并再次触发发射探头。为提高测量的稳定性和灵敏度，装置采用了稳定性好的电路。实验结果表明，使用该装置可以探测到0．5ns的超声波传播时间变化量。     

Nondestructive RAM Testing by Analyzing the Output Data for Symmetry

For the nondestructive march memory testing based on the symmetry analysis of the read out flows of output data, consideration was given to the conditions for manifestation of the bit-stuck, transition, and coupling faults and to construction of algorithms providing their hundred-percent covering by a minimum-complexity test and its minimum-complexity hardware realization.     

Frequency domain subspace identification of a tape servo system

As capacity demands for magnetic tape storage systems grow, servo actuator design for tracking data on high density tape media presents new modeling and control design challenges. In this paper a frequency weighted subspace identification algorithm is presented for control relevant model estimation of a tape servo actuator. Common to other subspace identification methods, the proposed algorithm is based on linear algebra techniques providing means for model order selection and model computation. The proposed subspace identification also allows for frequency dependent weightings to emphasize frequency data around the cross-over frequency to find models relevant for control design. The algorithm is applied to data obtained from a tape storage device, demonstrating model order selection and the estimation of servo actuator dynamics with control relevant model fit criteria.     

Quality control of polymer production processes

For the polymer production industries, the competitive edge will come from the technology that excels in controlling the polymer properties in a consistent way over the entire plant and in maximizing the production performance while keeping safety regulations. Based on the experience in applying advanced process control and scheduling schemes to industrial polyolefin polymerization plants, the state of the art in quality control systems for providing the polymer production plant with an enlarged capacity for product discrimination and flexibility is reviewed. On-line soft-sensing and optimal grade changeover control problems are the main focus of this paper. A quality control system for polymer production plants, which integrates optimal control with on-line sensing and scheduling techniques, is discussed making reference to an application of a prototype system to an industrial plant.     

Enhancement of photochromic hologram thermal stability

Significant enhancement of the thermal stability of the hologram recorded on photochromic materials had been achieved via covalent bonding of the photochromic dye to the polymer matrix as compared to the host-guest systems. One time partial reduction of the hologram’s initial diffraction efficiency due to thermal exposure was observed for both—polymers with attached dye as well as hostguest materials. Such one time reduction is interpreted to be due to the thermal relaxation of the polymer network induced with photochromic transition in the dye molecule. A gradual hologram erasure at elevated temperatures was observed for the host-guest system, which is assumed to be due to dye’s diffusion between highly lit and dark areas. For the photochromic materials with covalent boding of the dye to the polymer matrix the level of thermal stability is demonstrated such that at temperatures ca. 100C there was no detectable diffusion type degradation of the hologram after 6 hours of exposure to elevated temperature. Same heating of the hologram in photochromic host-guest polymer led to a full hologram erasure within 40 minutes. In both cases the one time initial DE reduction due to polymer matrix relaxation at elevated temperatures had comparable value of about 0.5 of hologram’s initial DE. The article is published in the original.