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Stability Analysis of Cliff Face around Kegon Falls in Nikko, Eastern Japan: An Implication to Its Erosional Mechanisms

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International Journal of Geosciences 2013年第6期4卷 8-16页

作者： Yuichi S. hayakawa Center for Spatial Information Science The University of Tokyo Chiba Japan

A waterfall highlights the locus of active fluvial erosion of bedrock, and its mechanism has been the subject of several studies;however, erosional processes remain to be clarified for specific rock structures composing a waterfall. Herein, the detailed morphology of cliffs around a waterfall is examined by a terrestrial laser scanning (TLS) approach to analyze erosional processes occurring in the cliffs. The study site is Kegon Falls in Japan, which has a vertical drop of surface water from the top of its cliff and groundwater outflows from its lower portion. The entire cliff is mostly overhanging and minor rockfalls are often observed. The latest major rockfall occurred in 1986, causing an approximate 8-m upstream shift of the waterfall lip. From the point cloud obtained by TLS measurement, a digital elevation model on a vertical plane was generated, and cross-sectional profiles were extracted. A distinct 5- to 10-m depression was found at the bottom of the upper andesite layer of the waterfall cliff, which appears to have been formed by freeze-thaw and wet-dry weathering following the upstream shift of the surface water drop. Stability analysis of the waterfall cliff with an undercutting notch indicates that the igneous rock composing the cliff is sufficiently strong to maintain its current overhanging shape and that catastrophic collapse of the entire waterfall face rarely occurs. Following the formation of the depression, the upper cliff face appears to have been gradually eroded by gravitational collapses of relatively small blocks bounded by columnar and platy joints.

关键词： Bedrock Erosion Knickpoint Waterfall Recession Terrestrial Laser Scanning

On the Tempo-Spatial Evolution of the Lower Ionospheric Perturbation for the 2016 Kumamoto Earthquakes from Comparisons of VLF Propagation Data Observed at Multiple Stations with Wave-Hop Theoretical Computations

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Open Journal of Earthquake Research 2018年第3期7卷 161-185页

作者： Tomokazu Asano Masashi hayakawa hayakawa Institute of Seismo Electromagnetics Co. Ltd. (Hi-SEM) University of Electro-Communications (UEC) Alliance Center 1-1-1 Kojima-cho Chofu Japan Advanced Wireless & Communications Research Center UEC Chofu Japan

There have been published many papers on VLF (very low frequency) characteristics to study seismo-ionospheric perturbations. Usually VLF records (amplitude and/or phase) are used to investigate mainly the temporal evolution of VLF propagation anomalies with special attention to one particular propagation path. The most important advantage of this paper is the simultaneous use of several propagation paths. A succession of earthquakes (EQs) happened in the Kumamoto area in Kyusyu Island;two strong foreshocks with magnitude of 6.5 and 6.4 on 14 April (UT) and the main shock with magnitude 7.3 on 15 April (UT). Because the EQ epicenters are not far from the VLF transmitter (with the call sign of JJI in Miyazaki prefecture), we can utilize simultaneously 8 observing stations of our network all over Japan. Together with the use of theoretical computations based on wave-hop theory, we try to trace both the temporal and spatial evolutions of the ionospheric perturbation associated with this succession of EQs. It is found that the ionospheric perturbation begins to appear about two weeks before the EQs, and this perturbation becomes most developed 5 - 3 days before the main shock. When the perturbation is most disturbed, the maximum change in vertical direction is depletion in the VLF effective ionospheric height of the order of 10 km, and its horizontal scale (or its radius) is about 1000 km. These spatio-temporal changes of the seismo-ionospheric perturbation will be investigated in details in the discus-sion, a comparison has made with the VLF characteristics of the 1995 Kobe with the same magnitude and of the same fault-type, and a brief discussion on the generation mechanism of seismo-ionospheric perturbation is finally made.

关键词： VLF/LF Propagation Anomaly Ionospheric Perturbations Earthquake Precursor Earthquake Prediction the 2016 Kumamoto Earthquakes Japanese VLF/LF Network Wave-Hop Computation Nighttime Fluctuation Method Atmospheric Oscillation Hypothesis

DISTRIBUTION AND CHARACTERIZATION OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN AIRBORNE PARTICULATES OF EAST ASIA

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China Particuology 2006年第6期4卷 283-292页

作者： Yan Liu Libin Liu Jin-Ming Lin Ning Tang Kazuichi hayakawa State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences p.o. Box 2871 Beijing 100085 China Graduate School of Natural Science and Technology Faculty of Pharmaceutical Sciences Kanazawa University Kakuma-machi Kanazawa 920-1192 Japan

A review is presented on the distribution and characterization of polycyclic aromatic hydrocarbons （PAHs） and their derivatives, including nitro-PAHs and hydro-PAHs, on atmospheric particulates of East Asia. Generally, PAH compounds with two or three aromatic rings are released mainly into the gas phase, while those containing three or more aromatic rings are associated with particulate matter （PM） emission. Particle-associated PAHs are primarily adsorbed on fine particles, and little associated with coarse particles. Investigation into the concentration level of PAHs in different areas can serve not only to reflect the pollutant status and sources but also to lead to the formulation of control strategies. The results of the present study show that China has more severe PAH pollution than such East Asian countries as Japan and Korea.

关键词： polycyclic aromatic hydrocarbon (PAH) airborne particulates distribution East Asia review

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Journal of Hydrodynamics 2001年第1期13卷 86-91页

作者： Wei Bing-qian, Kunihide Uchijima, Hiroshi hayakawa Department of Civil Engineering, Kitami Institude of Technology, 165, Koen-cho, Kitami, Hokkaido 090-8507, Japan Dep. of Civil Eng. Kitami Institute of Technol. 165 Koen-cho Hokkaido 090-8507 Japan

WT5”BZ]In this study, by considering the scale ratio related to the specific gravity of the submerged bed material, and introducing a degree of distortion, n the similarity laws for a distorted river model with a movable bed were derived under the conditions that the values of dual dimensionless parameters in a regime-criterion diagram for the bars are the same in a model as they are in a prototype, and that a resistance law such as the Manning-Strickler-type formula is to be valid for a model and a prototype. The usefulness of the similarity laws derived in this study was verified by comparing the bed forms from the distroted model experiments with the bed forms from the 1/50-scale undistorted model experiments, which were performed by the Hokkaido Development Bureau (H. D. B.), Japan, to examine the tentative plan for the improvement of a low-flow channel in the Chubetsu River, which is a tributary of the Ishikari River. It is considered that the distorted model experiments to be valid with either sand or lightweight bed material. [WT5”HZ]

关键词： similarity law regime-criterion diagram distorted model lightweight bed material alternate bars

Nitro-PAH exposures of occupationally-exposed traffic workers and associated urinary 1-nitropyrene metabolite concentrations

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Journal of Environmental Sciences 2016年第11期28卷 213-221页

作者： Justin P.Miller-Schulze Michael Paulsen Takayuki Kameda Akira Toriba Kazuichi hayakawa Brandon Cassidy Luke Naeher Manuel Aguilar Villalobos Christopher D.Simpson Department of Chemistry University of Washington WA 98195-1700 USA. Department of Environmental and Occupational Health Sciences University of Washington WA 98195 Seattle USA Laboratory of Hygienic Chemistry Instkute of Medical Pharmaceutical and Health Sciences Faculty of Pharmacy Kanazawa UniversityKakurna-machi Kanazawa Ishikawa 920-1192 Japan Graduate School of Natural Science and Technology Kanazawa University Kakma-machi Kanazawa Ishikawa 920-1192 Japan Department of Enuironmental Health Sciences University of Georgia Athens CA 30602-2102 USA Asociacion del Aire Ambiental Lima Peru

The assessment of occupational exposure to diesel exhaust（DE） is important from an epidemiological perspective. Urinary biomarkers of exposure have been proposed as a novel approach for measuring exposure to DE. In this study, we measured the concentrations of two urinary metabolites of 1-nitropyrene（1NP）, a nitrated polycyclic aromatic hydrocarbon that has been suggested as a molecular marker of diesel particulate matter. These two metabolites, 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene, were determined in urine samples（10 m L） from a small group of workers who were occupationally-exposed to vehicle exhaust in Trujillo, Peru, before and after their workshifts. Workshift exposures to1 NP, as well as PM_（2.5）, 2-nitropyrene and 2-nitrofluoranthene, were also *** to 1NP were similar in all studied workers, averaging 105 ± 57.9 pg/m^3（±standard deviation）. Median urinary concentrations of the average of the pre- and post-exposure samples for 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene, were found to be 3.9 and 2.3 pg metabolite/mg creatinine, respectively in the group of occupationally-exposed subjects（n = 17） studied. A direct relationship between workshift exposure to 1NP and urinary 1NP metabolites concentrations was not observed. However,the 1NP exposures and the creatinine-corrected urinary concentrations of the hydroxynitropyrene metabolites in these Peruvian traffic workers were similar to occupationally-exposed taxi drivers in Shenyang, China, and were higher than biomarker levels in office workers from Trujillo without occupational exposure to vehicle *** study provides further evidence that urinary metabolites of 1NP are associated with exposure to DE and may serve as a useful exposure biomarker.

关键词： Urinary biomarkers 1-Nitropyrene Diesel particulate matter

Anomalous phenomena in DC–ULF geomagnetic daily variation registered three days before the 12 May 2008 Wenchuan M_S 8.0 earthquake

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Earth and Planetary Physics 2019年第4期3卷 330-341页

作者： Mei Li Li Yao YaLi Wang Michel Parrot Masashi hayakawa Jun Lu HanDong Tan Tao Xie China Earthquake Networks Center China Earthquake Administration Beijing 100045 China Laboratoire de Physique et Chimie de l’Environnement et de l’Espace Université d’Orléans CNRS Orléans France hayakawa Institute of Seismo Electromagnetics Co. Ltd. University of Electro–Communications (UEC) Chofu Japan UEC Advanced Wireless Communications Research Center Chofu Japan School of Geophysics and Information Technology China University of Geosciences Beijing 100083 China

The hourly data of the vertical Z and the horizontal H components of 37 ground-based DC-ULF geomagnetic stations are examined during 20 April-12 May 2008. On 9 May 2008, three days before the Wenchuan MS 8.0 shock, anomalies-a double low-point and a decreased amplitude-are registered on the curves of the Z component at 25 stations in a large-scale area surrounding the Wenchuan epicentral area. The H component shows none of the double low-point phenomenon but does exhibit a reduced magnitude at the same time. The geomagnetic index Kp is also examined and indicates that the anomalies appear at a solar quiet period. The appearing time shift(Tzs) between the first low-point on May 9 and the minimum point occurring time of May 1-5, 2008 is also *** results show that Tzs is on the order of 1-2 hours earlier or later than usual and there is a 2-6 hours’ gap between these two lowpoints. However, there is still a transition area which includes the epicenter where Tzs=0. Variation amplitude examined on vertical Z increases as the distance from the epicenter decreases. An Earth-air-ionosphere model has been employed to investigate a possible mechanism of this phenomenon and positive results have been unexpectedly attained. All these above-related results tend to prove that the variations of the Z and H on May 9, 2008 during the solar quiet period are probably associated with the forthcoming Wenchuan MS 8.0 earthquake.

关键词： Wenchuan MS 8.0 earthquake geomagnetic abnormity spatial variations Earth-air-ionosphere model

Schumann resonance observation in China and anomalous disturbance possibly associated with Tohoku M9.0 earthquake

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Earthquake Science 2013年第2期26卷 137-145页

作者： Xinyang Ouyang Xuemin Zhang A.P.Nickolaenko M.hayakawa Xuhui Shen Yuanqing Miao Institute of Earthquake Science China Earthquake Administration63 Fuxing RoadP.O.Box 166 Beijing 100036China School of Earth and Space Sciences Peking University Usikov Institute of Radiophysics and Electronics hayakawa Institute of Seismo Electromagnetics Co. Ltd. UEC Incubation Center1-5-1 Chofugaoka Chofu Tokyo 182-8585Japan DFH Satellite Co. Ltd.China Academy of Space Technology

Schumann resonance （SR） is an electromag- netic resonance phenomenon in the Earth-ionosphere cavity exited by global lightning activities when the wavelength matches the circumference of the Earth, and the lowest four peak frequencies of SR are about 8, 14, 20, and 26 Hz. This article presents the new observational data of SR in China. The observations of two horizontal mag- netic components （BNs and BEw） in the frequency band range of 3-29 Hz at Yongsheng observatory （26.7°N, 100.8°E） in southwestern China were mainly analyzed. It is found that the SR amplitudes at peak frequencies in BNs and BEw components all showed diurnal and seasonal variations, and that the SR amplitude in BNS component is always higher than that in BEw component. Diurnal vari- ation of SR amplitude around equinoxes and solstices inBNs component is related to active intervals of three global thunderstorm centers, while SR amplitude in BEw com- ponent is the most significant at around 16 LT, corre- sponding to Asian center. SR amplitudes both in BNs and BEw components increase in the rainy season from May to September. In addition, the SR anomalies in association with the 2011 Japan earthquake are exhibited. The anom- alous effect was characterized by an increase in amplitude at the lowest four SR modes beginning at 4 days before this earthquake. Upon analyzing the wave interference between the direct wave and disturbed wave scattered by localized modification of lower ionosphere over the epicenter, Asian and African thunderstorm centers are found to contribute to anomalous effect observed at Yongsheng station. Modeling results of SR regular and disturbed spectra at different local times led to the similar conclusion.

关键词： Schumann resonance amplitudeThunderstorm center Anomalous Schumannresonance

STUDY ON A NEW TYPE OF SOFT RUBBER ACTUATOR WITH HUMAN COMPATIBILITY

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STUDY ON A NEW TYPE OF SOFT RUBBER ACTUATOR WITH HUMAN COMPA...

Multi-Resolution Landslide Susceptibility Analysis Using a DEM and Random Forest

第四届全国流体传动与控制学术会议

作者： Yasuhiro hayakawa Department of Electrical and Control Engineering Nara National College of Technology 22 Yata-cho Yamato-KoriyamaNaraJapan

In this paper, we investigate a new type of soft rubber actuator to realize a human friendly support device. Since the structure of the actuator is a soft mechanism that a sponge rubber is covered with silicone rubber, the actuator can realize a flexible motion to a human body. Further, the actuator can estimate external forces by making use of the equation with respect to the relation between inner pressure and external force. Therefore, the actuator can be used as a force sensor. In this study, we clear basic characteristics of the proposed actuator.

关键词： Pneumatic Soft Actuator Silicone Human Compatibility Hybrid Actuator

来源： cnki会议评论

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International Journal of Geosciences 2016年第5期7卷 726-743页

作者： Uttam Paudel Takashi Oguchi Yuichi hayakawa Department of Natural Environmental Studies Graduate School of Frontier Sciences The University of Tokyo Kashiwanoha Kashiwa Japan Center for Spatial Information Sciences The University of Tokyo Kashiwanoha Kashiwa Japan

Landslide susceptibility (LS) mapping is a requisite for safety against sediment related disasters, and considerable effort has been exerted in this discipline. However, the size heterogeneity and distribution of landslides still impose challenges in selecting an appropriate scale for LS studies. This requires identification of an optimal scale for landslide causative parameters. In this study, we propose a method to identify the optimum scale for each parameter and use multiple optimal parameter-scale combinations for LS mapping. A random forest model was used, together with 16 geomorphological parameters extracted from 10, 30, 60, 90, 120, 150, and 300 m digital elevation models (DEMs) and an inventory of historical landslides. Experiments in two equal-sized (625 km2) areas in Niigata and Ehime, Japan, with different geological and environmental settings and landslide density, demonstrated the efficiency of the proposed method. It outperformed all other single scale LS analysis with a prediction accuracy of 79.7% for Niigata and 78.62% for Ehime. Values of areas under receiver operating characteristics (ROC) curves (AUC) of 0.877 and 0.870 validate the application of the multi-scale model.

关键词： Multi-Resolution Landslide Susceptibility DEM Random Forest