The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Yixiang Duan - One of the best experts on this subject based on the ideXlab platform.
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Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement
Scientific Reports, 2015Co-Authors: Guang Yang, Di Tian, Yu Ding, Yixiang DuanAbstract:Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement
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Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement
Scientific Reports, 2015Co-Authors: Guang Yang, Qingyu Lin, Di Tian, Yu Ding, Yixiang DuanAbstract:A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective Signal Enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission Signal Enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum Signal Enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6-and 4.8-folds Signal Enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS.
Gerrit Van Der Ende - One of the best experts on this subject based on the ideXlab platform.
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Signal Enhancement through heteronuclear polarisation transfer in in-vivo ^31P MR spectroscopy of the human brain
Magnetic Resonance Materials in Physics Biology and Medicine, 2003Co-Authors: W. Weber-fahr, Dieter F Braus, Peter Bachert, Fritz A Henn, Gerrit Van Der EndeAbstract:Significant ^31P NMR Signal Enhancement through heteronuclear polarisation transfer was obtained in model solutions and in vivo on a 1.5-T whole-body MR scanner equipped with two RF channels. The much higher population differences involved in proton Zeeman energy levels can be transferred to the ^31P levels with the refocused INEPT (insensitive nucleus Enhancement by polarisation transfer) double-resonance experiment by means of a series of simultaneously applied broadband RF pulses. INEPT achieves a polarisation transfer from ^1H to ^31P spin states by directly reordering the populations in spin systems with heteronuclear scalar coupling. Thus, only the ^31P NMR Signal of metabolites with scalar ^1H–^31P coupling is amplified, while the other metabolite Signals in the spectra are suppressed. Compared to Ernst-angle excitation, a repetition-time-dependent Signal Enhancement of η =(29±3)% for methylene diphosphonic acid (MDPA) and η =(56±1)% for phosphorylethanolamine (PE) was obtained on model solutions through optimisation of the temporal parameters of the pulse experiment. The results are in good agreement with numerical calculations of the theoretical model for the studied spin systems. With optimised echo times, in-vivo ^31P Signal Enhancement of the same order was obtained in studies of the human brain.
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Signal Enhancement through heteronuclear polarisation transfer in in-vivo ^31P MR spectroscopy of the human brain
Magnetic Resonance Materials in Physics Biology and Medicine, 2003Co-Authors: W. Weber-fahr, Dieter F Braus, Peter Bachert, Fritz A Henn, Gerrit Van Der EndeAbstract:Significant ^31P NMR Signal Enhancement through heteronuclear polarisation transfer was obtained in model solutions and in vivo on a 1.5-T whole-body MR scanner equipped with two RF channels. The much higher population differences involved in proton Zeeman energy levels can be transferred to the ^31P levels with the refocused INEPT (insensitive nucleus Enhancement by polarisation transfer) double-resonance experiment by means of a series of simultaneously applied broadband RF pulses. INEPT achieves a polarisation transfer from ^1H to ^31P spin states by directly reordering the populations in spin systems with heteronuclear scalar coupling. Thus, only the ^31P NMR Signal of metabolites with scalar ^1H–^31P coupling is amplified, while the other metabolite Signals in the spectra are suppressed. Compared to Ernst-angle excitation, a repetition-time-dependent Signal Enhancement of η =(29±3)% for methylene diphosphonic acid (MDPA) and η =(56±1)% for phosphorylethanolamine (PE) was obtained on model solutions through optimisation of the temporal parameters of the pulse experiment. The results are in good agreement with numerical calculations of the theoretical model for the studied spin systems. With optimised echo times, in-vivo ^31P Signal Enhancement of the same order was obtained in studies of the human brain.
Guang Yang - One of the best experts on this subject based on the ideXlab platform.
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Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement
Scientific Reports, 2015Co-Authors: Guang Yang, Di Tian, Yu Ding, Yixiang DuanAbstract:Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement
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Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement
Scientific Reports, 2015Co-Authors: Guang Yang, Qingyu Lin, Di Tian, Yu Ding, Yixiang DuanAbstract:A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective Signal Enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission Signal Enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum Signal Enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6-and 4.8-folds Signal Enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS.
Akihiko Sugiyama - One of the best experts on this subject based on the ideXlab platform.
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ICASSP - Gain relaxation: A useful technique for Signal Enhancement with an unaware local noise source targeted at speech recognition
2016 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2016Co-Authors: Ryoji Miyahara, Akihiko SugiyamaAbstract:This paper proposes gain relaxation in Signal Enhancement designed for speech recognition with an unaware local noise source. An attention is drawn to a new performance degradation problem in Signal Enhancement combined with automatic speech recognition (ASR), which is encountered in real products with an unaware noise source. Gain relaxation, as a solution, selectively applies softer Enhancement of a target Signal to eliminate potential degradation in speech recognition caused by small undesirable distortion in the target Signal components. Evaluation of directional interference suppression with Signals recorded by a commercial PC (personal computer) demonstrates that Signal Enhancement over the input is achieved without sacrificing the performance for clean speech.
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phase randomization a new paradigm for single channel Signal Enhancement
International Conference on Acoustics Speech and Signal Processing, 2013Co-Authors: Akihiko Sugiyama, Ryoji MiyaharaAbstract:This paper proposes a new paradigm with phase randomization for single-channel Signal Enhancement. In contrast to literatures which pursue better target Signal quality, the new method tries to minimize artifacts in the residual noise. Applications of Signal Enhancement are revisited to highlight today's examples where environmental Signal is often considered as a part of target and SNR may take a negative value. A Signal example demonstrates that conventional Signal Enhancement with magnitude-only modification is insufficient from both objective and subjective points of view. A new framework with phase randomization as well as a specific algorithm is developed. Enhanced Signals show that phase randomization is an integral component for sufficient Enhancement. A subjective evaluation result demonstrates that the new paradigm with phase randomization is superior to the magnitude-only Enhancement with statistically significant differences.
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ICASSP - Phase randomization - A new paradigm for single-channel Signal Enhancement
2013 IEEE International Conference on Acoustics Speech and Signal Processing, 2013Co-Authors: Akihiko Sugiyama, Ryoji MiyaharaAbstract:This paper proposes a new paradigm with phase randomization for single-channel Signal Enhancement. In contrast to literatures which pursue better target Signal quality, the new method tries to minimize artifacts in the residual noise. Applications of Signal Enhancement are revisited to highlight today's examples where environmental Signal is often considered as a part of target and SNR may take a negative value. A Signal example demonstrates that conventional Signal Enhancement with magnitude-only modification is insufficient from both objective and subjective points of view. A new framework with phase randomization as well as a specific algorithm is developed. Enhanced Signals show that phase randomization is an integral component for sufficient Enhancement. A subjective evaluation result demonstrates that the new paradigm with phase randomization is superior to the magnitude-only Enhancement with statistically significant differences.
W. Weber-fahr - One of the best experts on this subject based on the ideXlab platform.
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Signal Enhancement through heteronuclear polarisation transfer in in-vivo ^31P MR spectroscopy of the human brain
Magnetic Resonance Materials in Physics Biology and Medicine, 2003Co-Authors: W. Weber-fahr, Dieter F Braus, Peter Bachert, Fritz A Henn, Gerrit Van Der EndeAbstract:Significant ^31P NMR Signal Enhancement through heteronuclear polarisation transfer was obtained in model solutions and in vivo on a 1.5-T whole-body MR scanner equipped with two RF channels. The much higher population differences involved in proton Zeeman energy levels can be transferred to the ^31P levels with the refocused INEPT (insensitive nucleus Enhancement by polarisation transfer) double-resonance experiment by means of a series of simultaneously applied broadband RF pulses. INEPT achieves a polarisation transfer from ^1H to ^31P spin states by directly reordering the populations in spin systems with heteronuclear scalar coupling. Thus, only the ^31P NMR Signal of metabolites with scalar ^1H–^31P coupling is amplified, while the other metabolite Signals in the spectra are suppressed. Compared to Ernst-angle excitation, a repetition-time-dependent Signal Enhancement of η =(29±3)% for methylene diphosphonic acid (MDPA) and η =(56±1)% for phosphorylethanolamine (PE) was obtained on model solutions through optimisation of the temporal parameters of the pulse experiment. The results are in good agreement with numerical calculations of the theoretical model for the studied spin systems. With optimised echo times, in-vivo ^31P Signal Enhancement of the same order was obtained in studies of the human brain.
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Signal Enhancement through heteronuclear polarisation transfer in in-vivo ^31P MR spectroscopy of the human brain
Magnetic Resonance Materials in Physics Biology and Medicine, 2003Co-Authors: W. Weber-fahr, Dieter F Braus, Peter Bachert, Fritz A Henn, Gerrit Van Der EndeAbstract:Significant ^31P NMR Signal Enhancement through heteronuclear polarisation transfer was obtained in model solutions and in vivo on a 1.5-T whole-body MR scanner equipped with two RF channels. The much higher population differences involved in proton Zeeman energy levels can be transferred to the ^31P levels with the refocused INEPT (insensitive nucleus Enhancement by polarisation transfer) double-resonance experiment by means of a series of simultaneously applied broadband RF pulses. INEPT achieves a polarisation transfer from ^1H to ^31P spin states by directly reordering the populations in spin systems with heteronuclear scalar coupling. Thus, only the ^31P NMR Signal of metabolites with scalar ^1H–^31P coupling is amplified, while the other metabolite Signals in the spectra are suppressed. Compared to Ernst-angle excitation, a repetition-time-dependent Signal Enhancement of η =(29±3)% for methylene diphosphonic acid (MDPA) and η =(56±1)% for phosphorylethanolamine (PE) was obtained on model solutions through optimisation of the temporal parameters of the pulse experiment. The results are in good agreement with numerical calculations of the theoretical model for the studied spin systems. With optimised echo times, in-vivo ^31P Signal Enhancement of the same order was obtained in studies of the human brain.
