Alphabet-independent linear-time construction of compressed suffix arrays using o(nlogn)-bit working space

Na, Joong Chae,Park, Kunsoo Elsevier 2007 Theoretical computer science Vol.385 No.1-3

<P><B>Abstract</B></P><P>The <I>suffix array</I> is a fundamental index data structure in string algorithms and bioinformatics, and the <I>compressed suffix array (CSA)</I> and the <I>FM-index</I> are its compressed versions. Many algorithms for constructing these index data structures have been developed. Recently, Hon et al. [W.K. Hon, K. Sadakane, W.K. Sung, Breaking a time-and-space barrier in constructing full-text indices, in: Proceedings of the 44th Annual IEEE Symposium on Foundations of Computer Science, 2003, pp. 251–260] proposed a construction algorithm using O(nloglog|Σ|) time and O(nlog|Σ|)-bit working space, which is the fastest algorithm using O(nlog|Σ|)-bit working space.</P><P>In this paper we give an efficient algorithm to construct the index data structures. Our algorithm constructs the suffix array, the CSA, the FM-index, and Burrows–Wheeler transform using alphabet-independent O(n) time and O(nlog|Σ|log|Σ|αn)-bit working space, where α=<SUB>log3</SUB>2. Our algorithm takes less time and more space than Hon et al.’s algorithm. Our algorithm uses least working space among alphabet-independent linear-time algorithms.</P>

Structure–Function Relationship in Glaucoma Patients With Parafoveal Versus Peripheral Nasal Scotoma

Jung, Kyoung In,Kang, Min Ku,Choi, Jin A.,Shin, Hye-Young,Park, Chan Kee The Association for Research in Vision and Ophthal 2016 Investigative Ophthalmology & Visual Science Vol.57 No.2

<P><B>Purpose</B></P><P>We evaluated whether the structure–function relationship in glaucoma patients with parafoveal scotoma or peripheral scotoma differs with the use of frequency doubling technology (FDT) or short-wavelength automated perimetry (SWAP) compared to standard automated perimetry (SAP).</P><P><B>Methods</B></P><P>Glaucoma patients with isolated parafoveal scotoma (PFS) within the central 10° of fixation in 1 hemifield and those with an isolated peripheral nasal step (PNS) within the nasal periphery outside 10° of fixation in one hemifield were studied. Peripapillary retinal nerve fiber layer (RNFL) thickness was measured using spectral-domain optical coherence tomography. The topographic relationships between structure and function were investigated.</P><P><B>Results</B></P><P>In the PNS group, superotemporal (<I>r</I><SUP>2</SUP> = 0.300, <I>P</I> = 0.001) and inferotemporal (<I>r</I><SUP>2</SUP> = 0.302, <I>P</I> = 0.001) RNFL thickness showed significant correlations with the corresponding visual field (VF) sensitivity using linear regression model in SAP. In the PFS group, temporal RNFL thickness was not correlated with nasal mean sensitivity (MS) on SAP (<I>r</I><SUP>2</SUP> = 0.103, <I>P</I> = 0.065). Using FDT, however, the temporal RNFL thickness was correlated with nasal MS in the PFS group (<I>r</I><SUP>2</SUP> = 0.277, <I>P</I> = 0.001). Using SWAP, the temporal RNFL thickness was not significantly associated with regional VF sensitivity in the PFS group (<I>r</I><SUP>2</SUP> = 0.052, <I>P</I> = 0.192).</P><P><B>Conclusions</B></P><P>In glaucoma with peripheral scotoma, the RNFL thickness was associated significantly with the corresponding VF loss in SAP, FDT, and SWAP. In eyes with PFS, however, the topographic structure–function relationships were not distinct with SAP or SWAP. Frequency doubling technology performed well in terms of structure–function correlation in glaucoma with PFS.</P>

Noncontact laser ultrasonic crack detection for plates with additional structural complexities

An, Yun-Kyu,Kwon, Yangsu,Sohn, Hoon SAGE Publications 2013 Structural health monitoring Vol.12 No.5

<P>This article presents a new noncontact laser ultrasonic wavefield imaging technique for detecting subsurface cracks in metallic plates with additional structural complexities. The proposed technique offers noncontact, automated, and baseline-free crack diagnosis for complex metal structures with potential to field structural health monitoring applications. First, a complete noncontact laser ultrasonic wavefield imaging system is introduced, and its working principle is presented. Then, a self-referencing frequency–wavenumber (<I>f</I>-<I>k</I>) filter is developed for instantaneous crack detection. The self-referencing <I>f</I>-<I>k</I> filter isolates crack-induced features from the ultrasonic wavefield images obtained only from the current state of the target structure using the noncontact laser ultrasonic wavefield imaging system. Finite element analyses are employed to investigate the characteristics of laser-generated ultrasonic waves and validate the proposed self-referencing <I>f</I>-<I>k</I> filter. Finally, the proposed technique is experimentally validated using asymmetrically tapered and vertically stiffened aluminum plates. The numerical and experimental results confirm that subsurface cracks are well identified and localized. The uniqueness of this study lies in that crack damage in plates even with additional structural features can be autonomously detected without using baseline data from the pristine condition of a target structure and with no sensor placement.</P>

Hollow-structured Fe₃O₄@SiO₂ nanoparticles: Novel synthesis and enhanced adsorbents for purification of plasmid DNA

An, Gye Seok,Chae, Dong Ho,Hur, Jae Uk,Oh, Ah Hyun,Choi, Hyun-Hee,Choi, Sung-Churl,Oh, Yoon-Suk,Jung, Yeon-Gil Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.15

<P><B>Abstract</B></P> <P>Fe<SUB>3</SUB>O<SUB>4</SUB> @SiO<SUB>2</SUB> core–shell-structured nanoparticles are expected to act as nanoabsorbents or nanocarriers because of the magnetic properties of the internal Fe<SUB>3</SUB>O<SUB>4</SUB> and the inherent properties of the external SiO<SUB>2</SUB>. Plasmid DNA, a small class of nucleic acid, is isolated and purified by the SiO<SUB>2</SUB> surface of magnetic beads. Improvement of the specific surface area of the SiO<SUB>2</SUB> coating layer under specified conditions greatly contributes to the purification performance of the material. As a means to achieve this, one way to maximize the surface area is to create a hollow structure by adding a coating layer. However, the process and environmental burdens associated with fabricating a hollow structure are some of the obstacles that currently prevent utilization of this method. This study proposes a novel synthesis method based on the use of water‐soluble surfactant, which can form an interlayer while simultaneously acting as a bridge between a core and a shell. The morphology changes of the SiO<SUB>2</SUB> layer depending on the crosslinking agent content were investigated, and the optimal conditions for hollow-structure generation were established. The improved surface properties dramatically improved the purification efficiency of plasmid DNA.</P>

A Roundabout Approach to Control Morphological Orientation and Solar‐Cell Performance by Modulating Side‐Chain Branching Position in Benzodithiophene‐Based Polymers

Lee, Kyu Cheol,Song, Seyeong,Lee, Junghoon,Kim, Dong Suk,Kim, Jin Young,Yang, Changduk WILEY‐VCH Verlag 2015 ChemPhysChem Vol.16 No.6

<P>To be meaningful to guide the rational design of novel high-performance conjugated semiconductors, we prepared three benzo[1,2-b:4,5-b]dithiophene (BDT)-based polymers by systematically moving the branching point of the alkyl chain. The effect of side-chain engineering was thoroughly investigated by a range of techniques. We demonstrate that a subtle change in the branching position in the BDT core can have a critical impact on polymer packing and preferential backbone orientation in thin films; copolymers made from BDT and thieno[3,4-c]pyrrole-4,6-dione units (TPD) adopt more of a face-on orientation as the branching point is shifted closer to the backbone, which can be correlated with a dramatic difference in solar-cells performance. The high short-circuit current density (11.6 mAcm(-2)) for the copolymer with one carbon atom between the alkoxylated oxygen atom and the branching point results from its predominantly face-on orientation and smoother surface in thin films, which results in power conversion efficiencies as high as 4.56%.</P>

p-Type Semiconducting GeSe Combs by a Vaporization–Condensation–Recrystallization (VCR) Process

Yoon, Seok Min,Song, Hyun Jae,Choi, Hee Cheul WILEY-VCH Verlag 2010 Advanced Materials Vol.22 No.19

<B>Graphic Abstract</B> <P>Novel p-type semiconductors can be found in these extraordinary comb structures. The GeSe combs are selectively formed by a vaporization–condensation–recrystallization (VCR) process using bulk GeSe powder as the precursor source. They have a flat body plate part and extended wire finger parts, both of which have identical crystal structures. The GeSe comb field-effect transistor device displays both p-type semiconducting and photo-switching behavior. <img src='wiley_img_2010/09359648-2010-22-19-ADMA200903719-content.gif' alt='wiley_img_2010/09359648-2010-22-19-ADMA200903719-content'> </P>

Syntheses, structures and magnetic properties of dinuclear oxo-bridged iron(III) complexes

Shin, Jong Won,Rowthu, Sankara Rao,Lee, Ju Eun,Lee, Hong In,Min, Kil Sik Elsevier 2012 Polyhedron Vol.33 No.1

<P><B>Graphical abstract</B></P><P>We have prepared three novel iron(III) complexes which show oxo-bridged dinuclear iron(III) structures. Complexes <B>1</B> and <B>3</B> display offset face-to-face π–π interactions between the dinuclear units, while <B>2</B> shows hydrogen bonding interactions via the hydroxyl group. The magnetic data of all the complexes indicate that very strong antiferromagnetic couplings occur via the oxo bridge within the iron(III) dimer and weak antiferromagnetic interactions exist between the dimers.</P><ce:figure id='f0040'></ce:figure> <P><B>Abstract</B></P><P>The reaction of tris(2-pyridylmethyl)amine (TPyA)/<I>N</I>,<I>N</I>-bis(2-pyridylmethyl)-2-aminoethanol (bpaeOH), H<SUB>2</SUB>DHBN/Na<SUB>2</SUB>C<SUB>2</SUB>O<SUB>4</SUB>/NaN<SUB>3</SUB> and Fe(II/III) ions in MeOH leads to the isolation of three iron(III) dimeric complexes, namely [(TPyA)(DHBN)Fe<SUP>III</SUP>OFe<SUP>III</SUP>(TPyA)(DHBN)]·2H<SUB>2</SUB>O (<B>1</B>), [(bpaeOH)(C<SUB>2</SUB>O<SUB>4</SUB>)Fe<SUP>III</SUP>OFe<SUP>III</SUP>(C<SUB>2</SUB>O<SUB>4</SUB>)(bpaeOH)]·2H<SUB>2</SUB>O (<B>2</B>) and [(TPyA)(N<SUB>3</SUB>)Fe<SUP>III</SUP>OFe<SUP>III</SUP>(N<SUB>3</SUB>)(TPyA)](ClO<SUB>4</SUB>)<SUB>2</SUB> (<B>3</B>) (H<SUB>2</SUB>DHBN=3,4-dihydroxybenzonitrile). These complexes have been investigated by single crystal X-ray diffractometry and magnetochemistry. Complexes <B>1</B>–<B>3</B> show dimeric structures with a bridging oxo (O<SUP>2−</SUP>) ion, and all the iron(III) ions have a distorted octahedral geometry. Complexes <B>1</B> and <B>3</B> have offset face-to-face π–π interactions between the dimers and possess a supramolecular structure, while <B>2</B> has O–H···O hydrogen bonding interactions between the dimers, which gives rise to a 1-D chain structure. These (<I>μ</I>-oxo)diiron(III) complexes exhibit antiferromagnetic interactions [<B>1</B>: <I>g</I>=2.0, <I>J</I>/<I>k</I><SUB>B</SUB>=−112K (−78cm<SUP>−1</SUP>), <I>θ</I>=−0.29K, <I>ρ</I>=0.035; <B>2</B>: <I>g</I>=2.0, <I>J</I>/<I>k</I><SUB>B</SUB>=−141K (−98cm<SUP>−1</SUP>), <I>θ</I>=−0.3K, <I>ρ</I>=0.01; <B>3</B>: <I>g</I>=2.0, <I>J</I>/<I>k</I><SUB>B</SUB>=−130K (−90cm<SUP>−1</SUP>), <I>θ</I>=−0.5K, <I>ρ</I>=0.009]. These indicate that very strong antiferromagnetic interactions occur via the oxo bridge within the iron(III) dimer and weak antiferromagnetic interactions exist between the dimers.</P>

Mesomorphic Organization and Thermochromic Luminescence of Dicyanodistyrylbenzene‐Based Phasmidic Molecular Disks: Uniaxially Aligned Hexagonal Columnar Liquid Crystals at Room Temperature with Enhanced Fluorescence Emission and Semiconductivity

Yoon, Seong‐,Jun,Kim, Jong H.,Kim, Kil Suk,Chung, Jong Won,Heinrich, Benoî,t,Mathevet, Fabrice,Kim, Pyosang,Donnio, Bertrand,Attias, André,‐,Jean,Kim, Dongho,Park, Soo Young WILEY‐VCH Verlag 2012 Advanced Functional Materials Vol.22 No.1

<P><B>Abstract</B></P><P>A new dicyanodistyrylbenzene‐based phasmidic molecule, (2Z,2′Z)‐2,2′‐(1,4‐phenylene)bis(3‐(3,4,5‐tris(dodecyloxy)phenyl)acrylonitrile), GDCS, is reported, which forms a hexagonal columnar liquid crystal (LC) phase at room temperature (RT). GDCS molecules self‐assemble into supramolecular disks consisting of a pair of molecules in a side‐by‐side disposition assisted by secondary bonding interactions of the lateral polar cyano group, which, in turn, constitute the hexagonal columnar LC structure. GDCS shows very intense green/yellow fluorescence in liquid/solid crystalline states, respectively, in contrast to the total absence of fluorescence emission in the isotropic melt state according to the characteristic aggregation‐induced enhanced emission (AIEE) behavior. The AIEE and two‐color luminescence thermochromism of GDCS are attributed to the peculiar intra‐ and intermolecular interactions of dipolar cyanostilbene units. It was found that the intramolecular planarization and restricted molecular motion associated with a specific stacking situation in the liquid/solid crystalline phases are responsible for the AIEE phenomenon. The origin of the two‐color luminescence was elucidated to be due to the interdisk stacking alteration in a given column driven by the specific local dipole coupling between molecular disks. These stacking changes, in turn, resulted in the different degree of excited‐state dimeric coupling to give different emission colors. To understand the complicated photophysical properties of GDCS, temperature‐dependent steady‐state and time‐resolved PL measurements have been comprehensively carried out. Uniaxially aligned and highly fluorescent LC and crystalline microwires of GDCS are fabricated by using the micromolding in capillaries (MIMIC) method. Significantly enhanced electrical conductivity (0.8 × 10<SUP>−5</SUP> S•cm<SUP>−1</SUP>/3.9 × 10<SUP>−5</SUP> S•cm<SUP>−1</SUP>) of the aligned LC/crystal microwires were obtained over that of multi‐domain LC sample, because of the almost perfect shear alignment of the LC material achieved in the MIMIC mold.</P>

Nanostructured Ferroelectrics: Fabrication and Structure–Property Relations

Han, Hee,Kim, Yunseok,Alexe, Marin,Hesse, Dietrich,Lee, Woo WILEY‐VCH Verlag 2011 Advanced Materials Vol. No.

<P><B>Abstract</B></P><P>With the continued demand for ultrahigh density ferroelectric data storage applications, it is becoming increasingly important to scale the dimension of ferroelectrics down to the nanometer‐scale region and to thoroughly understand the effects of miniaturization on the materials properties. Upon reduction of the physical dimension of the material, the change in physical properties associated with size reduction becomes extremely difficult to characterize and to understand because of a complicated interplay between structures, surface properties, strain effects from substrates, domain nucleation, and wall motions. In this Review, the recent progress in fabrication and structure‐property relations of nanostructured ferroelectric oxides is summarized. Various fabrication approaches are reviewed, with special emphasis on a newly developed stencil‐based method for fabricating ferroelectric nanocapacitors, and advantages and limitations of the processes are discussed. Stress‐induced evolutions of domain structures upon reduction of the dimension of the material and their implications on the electrical properties are discussed in detail. Distinct domain nucleation, growth, and propagation behaviors in nanometer‐scale ferroelectric capacitors are discussed and compared to those of micrometer‐scale counterparts. The structural effect of ferroelectric nanocapacitors on the domain switching behavior and cross‐talk between neighboring capacitors under external electric field is reviewed.</P>

Study of the effect of stress/strain of mesoporous Al-doped ZnO thin films on thermoelectric properties

Hong, Min-Hee,Choi, Haryeong,Shim, Dong Il,Cho, Hyung Hee,Kim, Jiwan,Park, Hyung-Ho Elsevier 2018 SOLID STATE SCIENCES Vol.82 No.-

<P><B>Abstract</B></P> <P>In this study, effects of induced stress and strain on the thermoelectric properties of mesoporous ZnO thin films with various Al doping concentrations were investigated. With Al doping in ZnO structure, the hexagonal wurtzite structure of ZnO was distorted owing to an ionic size difference between Al and Zn. With an increase in Al concentration to 4 at%, thermal conductivity unexpectedly decreased from 1.70 to 1.24 W/mK owing to an increase in the tensile strain, and electrical conductivity increased from 4 S/cm to 15 S/cm owing to an increase in the carrier concentration. Based on this study, the relationship between the induced strain owing to lattice distortion and thermoelectric properties was investigated. Thus, 4 at% Al-doped mesoporous ZnO demonstrated best enhanced thermoelectric properties.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Al-doped mesoporous ZnO film synthesized by evaporation-induced self-assembly process. </LI> <LI> Crystal structure of Al-doped ZnO was distorted owing to difference ionic radii between Al<SUP>3+</SUP> and Zn<SUP>2+</SUP>. </LI> <LI> Al-doping induced stress/strain in mesoporous ZnO structure was calculated using Williamson-Hall analysis. </LI> <LI> Correlation between stress/strain and thermoelectric properties were analyzed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>