244 research outputs found

    Lyrics-to-Audio Alignment and its Application

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    Automatic lyrics-to-audio alignment techniques have been drawing attention in the last years and various studies have been made in this field. The objective of lyrics-to-audio alignment is to estimate a temporal relationship between lyrics and musical audio signals and can be applied to various applications such as Karaoke-style lyrics display. In this contribution, we provide an overview of recent development in this research topic, where we put a particular focus on categorization of various methods and on applications

    Syntheses and properties of self-alignable conjugated polymers

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    Thesis (Ph.D. in Engineering)--University of Tsukuba, (A), no. 1703, 1997.3.2

    Liquid crystal electropolymerisation under magnetic field and resultant linear polarised electrochromism

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    The electrochemical preparation of poly(3,4-ethylenedioxythiophene) (PEDOT) is conducted in liquid crystal (LC) electrolyte solution with nematic (N), cholesteric (Ch*), and smectic A (SmA) phases under a magnetic field. The polymer imprints the molecular arrangement of the LC electrolyte during the polymerisation process. The oriented polymers thus obtained displays optical texture characteristics that resemble those of the LC electrolyte solution. Especially, visualization of SmA domain through PEDOTfibrils is achieved. The magnetic alignment produces linear optical polarisation for the polymers. The PEDOTs thus prepared exhibit good reproducible electroactivity. The present electropolymerisation under magnetic field affords polymer films with linear polarised electrochromism

    Estimation of the helical twisting power of chiral inducers by time-dependent density functional theory (TD-DFT) for electrochemical polymerization in cholesteric liquid crystals

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    Five chiral compounds were designed and synthesized using the Mitsunobu reaction to act as chiral inducers (i.e., chiral dopants) for the transformation of a nematic liquid crystal (LC) (4-n-octoxy-4′-cyanobiphenyl) into a cholesteric LC. These chiral inducers contain two types of chiral alkyl chains with different kinds of achiral mesogenic cores (biphenylcarboxylate, biphenoxy, and cyanobiphenoxy). We observed that the achiral mesogenic cores affected the helical twisting power in terms of both induction strength and helicity (left-/right-hand introduction). All the ester type inducers exhibited a positive Cotton effect and right-hand helical twisting power (HTP). However, ethers exhibited a negative Cotton effect and left-hand HTP. The microscopic HTPs (βM) of these inducers demonstrate a linear relation with their optical activities (ellipticity near the absorption maximum). Further, the time-dependent density functional theory (TD–DFT) calculation using the B3LYP/6-311++G (d, p) method has been used to predict the circular dichroism spectra of these inducers. The predicted optical activity was observed to be in accordance with that observed in the experimental result. This study proposes a method for predicting the HTP of chiral inducers that can be applied to achieve polymerization in the reaction fields of cholesteric LCs

    Synthesis of magneto-optically active polyanilines

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    We report preparation of polyaniline (PANI) with radicals on the N-positions. Chirality of a PANI having optically active substituent is retained even upon oxidation by m-chloroperoxybenzoic acid in chloroform to generate spin species. Electron spin resonance and circular dichroism spectroscopy measurements suggest that the chiral paramagnetic properties of PANIs are derived from the combination of chiral side chains and oxyradicals in the structure of the polymer. This report focuses on a new synthetic approach for obtaining magneto-optically active polyanilines

    A Modeling of Singing Voice Robust to Accompaniment Sounds and Its Application to Singer Identification and Vocal-Timbre-Similarity-Based Music Information Retrieval

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    This paper describes a method of modeling the characteristics of a singing voice from polyphonic musical audio signals including sounds of various musical instruments. Because singing voices play an important role in musical pieces with vocals, such representation is useful for music information retrieval systems. The main problem in modeling the characteristics of a singing voice is the negative influences caused by accompaniment sounds. To solve this problem, we developed two methods, accompaniment sound reduction and reliable frame selection . The former makes it possible to calculate feature vectors that represent a spectral envelope of a singing voice after reducing accompaniment sounds. It first extracts the harmonic components of the predominant melody from sound mixtures and then resynthesizes the melody by using a sinusoidal model driven by these components. The latter method then estimates the reliability of frame of the obtained melody (i.e., the influence of accompaniment sound) by using two Gaussian mixture models (GMMs) for vocal and nonvocal frames to select the reliable vocal portions of musical pieces. Finally, each song is represented by its GMM consisting of the reliable frames. This new representation of the singing voice is demonstrated to improve the performance of an automatic singer identification system and to achieve an MIR system based on vocal timbre similarity

    Electrosynthesis of Conducting Polymers in Lecithin Liquid Crystal Reaction Field

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    Lecithin is a biological material that exhibits lyotropic liquid crystal form at certain concentrations in water. Specifically, lecithin forms lamellar structures like a smectic phase layers. We describe electro-oxidative preparation of polymers such as polyaniline (PANI), poly(ethylenedioxythiophene) (PEDOT), and polypyrrole (PPy) in a lecithin liquid crystal matrix. Cross-shaped images (Maltese crosses) derived from lamellar structures were observed for the resultant polymer film with a polarizing optical microscopy under crossed Nicol condition. Lecithin lamellar structure in the water was transcribed to the resultant polymers during the electropolymerization. This research demonstrates transcription of a liquid crystal aggregation form of biomaterials onto synthetic polymers through electrochemical process

    Synthesis of Carbon Showing Weak Antiferromagnetic Behavior at a Low Temperature

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    In this short communication, we report a new carbon material prepared from meta-linked polyaniline that exhibits weak antiferromagnetic interactions at low temperature. The synthesis of poly(meta-aniline), abbreviated as m-PANI, was conducted using the Ullmann reaction with the aid of Cu+ as a catalyst in the presence of K2CO3. After the generation of radical cations by vapor-phase doping with iodine, carbonization was performed to prepare carbon polyaniline (C-PANI), which comprises condensed benzene rings. Analysis with a superconducting quantum interference device revealed that the resultant carbon exhibits antiferromagnetism at low temperatures. The discovery of this weak antiferromagnetic carbon may contribute to the development of carbon magnets

    Design and Performance of Remote Controlled ^3He Refrigerator in Hybrid Magnet(Part II. Several Instruments and Techniques Developed in HFLSM)

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    A remote controlled ^3He refrigerator for use in a hybrid magnet is described. Temperatures between 1.3 K and 0.43 K can be remote controlled by ^3He vapor pressure within the temperature drift of 0.01 K in magnetic fields up to 23 T. Using this refrigerator, several kinds of physical measurements, such as electrical resistance, capacitance and ultrasonic attenuation, have been carried out without being disturbed by noise peculiar to the hybrid magnet system. Additionally, magnetic field dependence of capacitance thermometers at liquid ^3He temperatures is discussed

    Synthesis of Polyazobenzenes Exhibiting Photoisomerization and Liquid Crystallinity

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    While only a few studies have investigated the synthesis of main chain-type polyazobenzenes, they continue to draw an increasing amount of attention owing to their industrial applications in holography, dyes, and functional adhesives. In this study, dibromoazobenzene was prepared as a monomer for constructing azo-based π-conjugated polymers. Miyaura–Suzuki cross-coupling polymerization was conducted to develop copolymers containing an azobenzene unit as a photoisomerization block and a pyrimidine-based liquid crystal generator block. The prepared polymers exhibited thermotropic liquid crystallinity and underwent cis and trans photoisomerization upon irradiation with ultraviolet and visible light. Furthermore, the photoisomerization behavior was examined using optical absorption spectroscopy and synchrotron X-ray diffraction spectrometry
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