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Hitachi (Japan)

companyTokyo, Japan

Research output, citation impact, and the most-cited recent papers from Hitachi (Japan) (Japan). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
51.4K
Citations
1.8M
h-index
341
i10-index
39.0K
Also known as
Hitachi (Japan)Kabushiki-gaisha Hitachi Seisakusho日立製作所

Top-cited papers from Hitachi (Japan)

New Fe-based soft magnetic alloys composed of ultrafine grain structure
Y. Yoshizawa, S Oguma, Kenta Yamauchi
1988· Journal of Applied Physics3.4Kdoi:10.1063/1.342149

The magnetic properties of Fe-Si-B-M (M: additives) alloys prepared by annealing amorphous alloys made by the single roller method over their crystallization temperature have been investigated for development of new Fe-based soft magnetic alloys. Excellent soft magnetic properties were obtained by adding the two elements Cu and Nb to Fe-Si-B alloys. It was found that these new alloys, called ‘‘FINEMET,’’ have an ultrafine grain structure composed of bcc Fe solid solution. They are suitable for many kinds of magnetic components such as saturable reactors, choke coils, and transformers, because they have superior soft magnetic properties and a high saturation flux density, and because different types of B-H hysteresis loops are obtained by magnetic field annealing.

Dynamic itemset counting and implication rules for market basket data
Sergey Brin, Rajeev Motwani, Jeffrey D. Ullman, Shalom Tsur⋆
19972.0Kdoi:10.1145/253260.253325

We consider the problem of analyzing market-basket data and present several important contributions. First, we present a new algorithm for finding large itemsets which uses fewer passes over the data than classic algorithms, and yet uses fewer candidate itemsets than methods based on sampling. We investigate the idea of item reordering, which can improve the low-level efficiency of the algorithm. Second, we present a new way of generating "implication rules," which are normalized based on both the antecedent and the consequent and are truly implications (not simply a measure of co-occurrence), and we show how they produce more intuitive results than other methods. Finally, we show how different characteristics of real data, as opposed to synthetic data, can dramatically affect the performance of the system and the form of the results. 1 Introduction Within the area of data mining, the problem of deriving associations from data has recently received a great deal of attention. The prob...

Breast Disease: Clinical Application of US Elastography for Diagnosis
Ako Itoh, Ei Ueno, Eriko Tohno, Hiroshi Kamma +4 more
2006· Radiology1.6Kdoi:10.1148/radiol.2391041676

PURPOSE: To evaluate the diagnostic performance of real-time freehand elastography by using the extended combined autocorrelation method (CAM) to differentiate benign from malignant breast lesions, with pathologic diagnosis as the reference standard. MATERIALS AND METHODS: This study was approved by the University of Tsukuba Human Subjects Institutional Review Board; all patients gave informed consent. Conventional ultrasonography (US) and real-time US elastography with CAM were performed in 111 women (mean age, 49.4 years; age range, 27-91 years) who had breast lesions (59 benign, 52 malignant). Elasticity images were assigned an elasticity score according to the degree and distribution of strain induced by light compression. The area under the curve and cutoff point, both of which were obtained by using a receiver operating characteristic curve analysis, were used to assess diagnostic performance. Mean scores were examined by using a Student t test. Sensitivity, specificity, and accuracy were compared by using the standard proportion difference test or the Delta-equivalent test. RESULTS: For elasticity score, the mean +/- standard deviation was 4.2 +/- 0.9 for malignant lesions and 2.1 +/- 1.0 for benign lesions (P < .001). When a cutoff point of between 3 and 4 was used, elastography had 86.5% sensitivity, 89.8% specificity, and 88.3% accuracy. When a best cutoff point of between 4 and 5 was used, conventional US had 71.2% sensitivity, 96.6% specificity, and 84.7% accuracy. Elastography had higher sensitivity than conventional US (P < .05). By using equivalence bands for noninferiority or equivalence, it was shown that the specificity of elastography was not inferior to that of conventional US and that the accuracy of elastography was equivalent to that of conventional US. CONCLUSION: For assessing breast lesions, US elastography with the proposed imaging classification, which was simple compared with that of the Breast Imaging Recording and Data System classification, had almost the same diagnostic performance as conventional US.

FinFET-a self-aligned double-gate MOSFET scalable to 20 nm
Chenming Hu, Jeffrey Bokor, Tsu‐Jae King, Erik Anderson +4 more
2000· IEEE Transactions on Electron Devices1.6Kdoi:10.1109/16.887014

MOSFETs with gate length down to 17 nm are reported. To suppress the short channel effect, a novel self-aligned double-gate MOSFET, FinFET, is proposed. By using boron-doped Si/sub 0.4/Ge/sub 0.6/ as a gate material, the desired threshold voltage was achieved for the ultrathin body device. The quasiplanar nature of this new variant of the vertical double-gate MOSFETs can be fabricated relatively easily using the conventional planar MOSFET process technologies.

Low Temperature Surface Cleaning of Silicon and Its Application to Silicon MBE
Akitoshi Ishizaka, Y. Shiraki
1986· Journal of The Electrochemical Society1.6Kdoi:10.1149/1.2108651

A low temperature thermal cleaning method for Si molecular beam epitaxy (MBE) is proposed. This method consists of wet chemical treatment to eliminate carbon contaminants on Si substrates, thin oxide film formation to protect the clean Si surface from contamination during processing before MBE growth, and desorption of the thin oxide film under UHV. The passivative oxide can be removed at temperatures below 800°C. It is confirmed that Si epitaxial growth can take place on substrates cleaned by this method and that high quality Si layers with dislocations of fewer than 100/cm2 and high mobility comparable to good bulk materials are formed. Surface cleanliness, the nature of thin passivative oxide films, and cleaning processes are also studied by using such surface analytic methods as Auger electron spectroscopy, reflection high energy electron diffraction, and x‐ray photoelectron spectroscopy.

Standardization of left atrial, right ventricular, and right atrial deformation imaging using two-dimensional speckle tracking echocardiography: a consensus document of the EACVI/ASE/Industry Task Force to standardize deformation imaging
Luigi P. Badano, Theodore J. Kolias, Denisa Muraru, Theodore P. Abraham +4 more
2018· European Heart Journal - Cardiovascular Imaging1.6Kdoi:10.1093/ehjci/jey042

The EACVI/ASE/Industry Task Force to standardize deformation imaging prepared this consensus document to standardize definitions and techniques for using two-dimensional (2D) speckle tracking echocardiography (STE) to assess left atrial, right ventricular, and right atrial myocardial deformation. This document is intended for both the technical engineering community and the clinical community at large to provide guidance on selecting the functional parameters to measure and how to measure them using 2D STE.This document aims to represent a significant step forward in the collaboration between the scientific societies and the industry since technical specifications of the software packages designed to post-process echocardiographic datasets have been agreed and shared before their actual development. Hopefully, this will lead to more clinically oriented software packages which will be better tailored to clinical needs and will allow industry to save time and resources in their development.

Tunnel magnetoresistance of 604% at 300K by suppression of Ta diffusion in CoFeB∕MgO∕CoFeB pseudo-spin-valves annealed at high temperature
Shoji Ikeda, Jun Hayakawa, Yoshito Ashizawa, Y. M. Lee +4 more
2008· Applied Physics Letters1.5Kdoi:10.1063/1.2976435

The authors observed tunnel magnetoresistance (TMR) ratio of 604% at 300K in Ta∕Co20Fe60B20∕MgO∕Co20Fe60B20∕Ta pseudo-spin-valve magnetic tunnel junction annealed at 525°C. To obtain high TMR ratio, it was found critical to anneal the structure at high temperature above 500°C, while suppressing the Ta diffusion into CoFeB electrodes and in particular to the CoFeB∕MgO interface. X-ray diffraction measurement of MgO on SiO2 or Co20Fe60B20 shows that an improvement of MgO barrier quality, in terms of the degree of the (001) orientation and stress relaxation, takes place at annealing temperatures above 450°C. The highest TMR ratio observed at 5K was 1144%.

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
Amitav Mukherjee, S. Ali. A. Fakoorian, Jing Huang, A. Lee Swindlehurst
2014· IEEE Communications Surveys & Tutorials1.5Kdoi:10.1109/surv.2014.012314.00178

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.

GaInNAs: A Novel Material for Long-Wavelength-Range Laser Diodes with Excellent High-Temperature Performance
Masahiko Kondow, K. Uomi, Atsuko Niwa, T. Kitatani +2 more
1996· Japanese Journal of Applied Physics1.4Kdoi:10.1143/jjap.35.1273

We propose a novel material, GaInNAs, that can be formed on GaAs to drastically improve the temperature characteristics ( T 0 ) in long-wavelength-range laser diodes. The feasibility of our proposal is demonstrated experimentally.

Definitions for a common standard for 2D speckle tracking echocardiography: consensus document of the EACVI/ASE/Industry Task Force to standardize deformation imaging
Jens‐Uwe Voigt, Gianni Pedrizzetti, Peter Lysyansky, Thomas H. Marwick +4 more
2014· European Heart Journal - Cardiovascular Imaging1.3Kdoi:10.1093/ehjci/jeu184

Recognizing the critical need for standardization in strain imaging, in 2010, the European Association of Echocardiography (now the European Association of Cardiovascular Imaging, EACVI) and the American Society of Echocardiography (ASE) invited technical representatives from all interested vendors to participate in a concerted effort to reduce intervendor variability of strain measurement. As an initial product of the work of the EACVI/ASE/Industry initiative to standardize deformation imaging, we prepared this technical document which is intended to provide definitions, names, abbreviations, formulas, and procedures for calculation of physical quantities derived from speckle tracking echocardiography and thus create a common standard.

Magnetoresistance in magnetic manganese oxide with intrinsic antiferromagnetic spin structure
Ken-ichi Chahara, Toshiyuki Ohno, Masahiro Kasai, Y. Kozono
1993· Applied Physics Letters1.2Kdoi:10.1063/1.110624

Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin-dependent electron scattering due to spin canting of the manganese oxide.

Shape from focus
Shree K. Nayar, Yasuo Nakagawa
1994· IEEE Transactions on Pattern Analysis and Machine Intelligence1.2Kdoi:10.1109/34.308479

The shape from focus method presented here uses different focus levels to obtain a sequence of object images. The sum-modified-Laplacian (SML) operator is developed to provide local measures of the quality of image focus. The operator is applied to the image sequence to determine a set of focus measures at each image point. A depth estimation algorithm interpolates a small number of focus measure values to obtain accurate depth estimates. A fully automated shape from focus system has been implemented using an optical microscope and tested on a variety of industrial samples. Experimental results are presented that demonstrate the accuracy and robustness of the proposed method. These results suggest shape from focus to be an effective approach for a variety of challenging visual inspection tasks.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Self-Assembled Hexa- <i>peri</i> -hexabenzocoronene Graphitic Nanotube
Jonathan P. Hill, Wusong Jin, Atsuko Kosaka, Takanori Fukushima +4 more
2004· Science1.0Kdoi:10.1126/science.1097789

An amphiphilic hexa-peri-hexabenzocoronene self-assembles to form a pi-electronic, discrete nanotubular object. The object is characterized by an aspect ratio greater than 1000 and has a uniform, 14-nanometer-wide, open-ended hollow space, which is an order of magnitude larger than those of carbon nanotubes. The wall is 3 nanometers thick and consists of helical arrays of the pi-stacked graphene molecule, whose exterior and interior surfaces are covered by hydrophilic triethylene glycol chains. The graphitic nanotube is redox active, and a single piece of the nanotube across 180-nanometer-gap electrodes shows, upon oxidation, an electrical resistance of 2.5 megohms at 285 kelvin [corrected]. This family of molecularly engineered graphite with a one-dimensional tubular shape and a chemically accessible surface constitutes an important step toward molecular electronics.

Rice Annotation Project Database (RAP-DB): An Integrative and Interactive Database for Rice Genomics
Hiroaki Sakai, Sung Shin Lee, Tsuyoshi Tanaka, Hisataka Numa +4 more
2013· Plant and Cell Physiology941doi:10.1093/pcp/pcs183

The Rice Annotation Project Database (RAP-DB, http://rapdb.dna.affrc.go.jp/) has been providing a comprehensive set of gene annotations for the genome sequence of rice, Oryza sativa (japonica group) cv. Nipponbare. Since the first release in 2005, RAP-DB has been updated several times along with the genome assembly updates. Here, we present our newest RAP-DB based on the latest genome assembly, Os-Nipponbare-Reference-IRGSP-1.0 (IRGSP-1.0), which was released in 2011. We detected 37,869 loci by mapping transcript and protein sequences of 150 monocot species. To provide plant researchers with highly reliable and up to date rice gene annotations, we have been incorporating literature-based manually curated data, and 1,626 loci currently incorporate literature-based annotation data, including commonly used gene names or gene symbols. Transcriptional activities are shown at the nucleotide level by mapping RNA-Seq reads derived from 27 samples. We also mapped the Illumina reads of a Japanese leading japonica cultivar, Koshihikari, and a Chinese indica cultivar, Guangluai-4, to the genome and show alignments together with the single nucleotide polymorphisms (SNPs) and gene functional annotations through a newly developed browser, Short-Read Assembly Browser (S-RAB). We have developed two satellite databases, Plant Gene Family Database (PGFD) and Integrative Database of Cereal Gene Phylogeny (IDCGP), which display gene family and homologous gene relationships among diverse plant species. RAP-DB and the satellite databases offer simple and user-friendly web interfaces, enabling plant and genome researchers to access the data easily and facilitating a broad range of plant research topics.

Possible Species of “Ferroelastic” Crystals and of Simultaneously Ferroelectric and Ferroelastic Crystals
Kêitsirô Aizu
1969· Journal of the Physical Society of Japan911doi:10.1143/jpsj.27.387

It is convenient to grasp crystals of a kind as “ferroelastic” crystals. They are defined analogously to “ferroelectric” crystals, mechanical strain and stress in the former corresponding to electric polarization and field in the latter respectively. The order of magnitude of the coercive stress for ferroelastic state-shifts which corresponds to the coercive field for ferroelectric state-shifts is expected, on the average, to be 10 2 newt·cm -2 . A determination is made of all theoretically possible species of ferroelastic crystals and the number of states and ferroelectricity or nonferroelctricity in each of these species. It is found that there are 94 of these ferroelastic species and that 42 of them are simultaneously ferroelectric. Incidentally, an alteration is made of the hitherto used symbols for the 88 species of ferroeletric crystals.

Japanese Evaluated Nuclear Data Library Version 3 Revision-2: JENDL-3.2.
Tsuneo NAKAGAWA, Keiichi SHIBATA, Satoshi Chiba, Tokio Fukahori +4 more
1995· Journal of Nuclear Science and Technology905doi:10.3327/jnst.32.1259

The revision work of JENDL-3 has been made by considering feedback information of various benchmark tests. The main revised quantities are the resonance parameters, capture and inelastic scattering cross sections, and fission spectra of main actinide nuclides, the total and inelastic scattering cross sections of structural materials, the resonance parameters the capture and inelastic scattering cross sections of fission products, and the γr-ray production data. The revised data were released as JENDL-3.2 in June 1994. The preliminary benchmark tests indicate that JENDL-3.2 predicts various reactor characteristics more successfully than the previous version of JENDL-3.1.

Possible Species of Ferromagnetic, Ferroelectric, and Ferroelastic Crystals
Kêitsirô Aizu
1970· Physical review. B, Solid state778doi:10.1103/physrevb.2.754

A ferromagnetic, ferroelectric, or ferroelastic crystal is called full or partial, according to whether all or not all but some of its orientation states are different in spontaneous magnetization vector, spontaneous polarization vector, or spontaneous strain tensor. In previous theories --- for nonmagnetic crystals --- the concept of "species" was introduced, a determination was made of all possible species of full ferroelectrics and of full ferroelastics, and those species were found in which ferroelectricity and ferroelasticity coexist and completely couple with each other. These theories are now extended to cover magnetic crystals in addition to nonmagnetic crystals and to cover the partial in addition to the full. A determination is made of all possible species of full ferromagnetics, partial ferromagnetics, full ferroelectrics, partial ferroelectrics, full ferroelastics, and partial ferroelastics, and it is found out in which of these species two or all of ferromagnetism, ferroelectricity, and ferroelasticity should couple completely or incompletely with each other.

Sounds and silence: An optical topography study of language recognition at birth
Marcela Peña, Atsushi Maki, Damir Kovačić, Ghislaine Dehaene‐Lambertz +3 more
2003· Proceedings of the National Academy of Sciences729doi:10.1073/pnas.1934290100

Does the neonate's brain have left hemisphere (LH) dominance for speech? Twelve full-term neonates participated in an optical topography study designed to assess whether the neonate brain responds specifically to linguistic stimuli. Participants were tested with normal infant-directed speech, with the same utterances played in reverse and without auditory stimulation. We used a 24-channel optical topography device to assess changes in the concentration of total hemoglobin in response to auditory stimulation in 12 areas of the right hemisphere and 12 areas of the LH. We found that LH temporal areas showed significantly more activation when infants were exposed to normal speech than to backward speech or silence. We conclude that neonates are born with an LH superiority to process specific properties of speech.

Evidence for Aharonov-Bohm effect with magnetic field completely shielded from electron wave
Akira Tonomura, Nobuyuki Osakabe, Tsuyoshi Matsuda, Takeshi Kawasaki +3 more
1986· Physical Review Letters722doi:10.1103/physrevlett.56.792

Evidence for the Aharonov-Bohm effect was obtained with magnetic fields shielded from the electron wave. A toroidal ferromagnet was covered with a superconductor layer to confine the field, and further with a copper layer for complete shielding from the electron wave. The expected relative phase shift was detected with electron holography between two electron beams, one passing through the hole of the toroid, and the other passing outside. The experiment gave direct evidence for flux quantization also.

Regulation of Levels of Proline as an Osmolyte in Plants under Water Stress
Yoshu Yoshiba, Tomohiro Kiyosue, Kazuo Nakashima, Kazuko Yamaguchi‐Shinozaki +1 more
1997· Plant and Cell Physiology701doi:10.1093/oxfordjournals.pcp.a029093

Compatible osmolytes are potent osmoprotectants that play a role in counteracting the effects of osmotic stress. Proline (Pro) is one of the most common compatible osmolytes in water-stressed plants. The accumulation of Pro in dehydrated plants is caused both by activation of the biosynthesis of Pro and by inactivation of the degradation of Pro. In plants, L-Pro is synthesized from L-glutamic acid (L-Glu) via delta(1)-pyrroline-5-carboxylate (P5C) by two enzymes, P5C synthetase (P5CS) and P5C reductase (P5CR). L-Pro is metabolized to L-Glu via P5C by two enzymes, proline dehydrogenase (oxidase) (ProDH; EC 1.5.99.8) and P5C dehydrogenase (P5CDH; EC 1.5.1.12). Such metabolism of Pro is inhibited when Pro accumulates during dehydration and it is activated when rehydration occurs. Under dehydration conditions, when expression of the gene for P5CS is strongly induced, expression of the gene for ProDH is inhibited. By contrast, under rehydration conditions, when the expression of the gene for ProDH is strongly induced, the expression of the gene for P5CS is inhibited. Thus, P5CS, which acts during the biosynthesis of Pro, and ProDH, which acts during the metabolism of Pro, appear to be the rate-limiting factors under water stress. Therefore, it is suggested that levels of Pro are regulated at the level of transcriptional the genes of these two enzymes during dehydration and rehydration. Moreover, it has been demonstrated that Pro acts as an osmoprotectant and that overproduction of Pro results in increased tolerance to osmotic stress of transgenic tobacco plants. Genetically engineered crop plants that overproduce Pro might, thus, acquire osmotolerance, namely, the ability to tolerate environmental stresses such as drought and high salinity.