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Tool path generation and optimization for freeform surface diamond turning based on an independently controlled fast tool servo

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International Journal of Extreme Manufacturing 2022年第2期4卷 145-160页

作者： Yusuke sato Jiwang Yan Department of Mechanical Engineering Keio UniversityYokohama 223-8522Japan

Diamond turning based on a fast tool servo(FTS)is widely used in freeform optics fabrication due to its high accuracy and machining *** a new trend,recently developed high-frequency and long-stroke FTS units are independently driven by a separate control system from the machine tool ***,the tool path generation strategy for the independently controlled FTS is far from *** study aims to establish methods for optimizing tool path for the independent control FTS to reduce form errors in a single step of *** from the conventional integrated FTS control system,where control points are distributed in a spiral pattern,in this study,the tool path for the independent FTS controller is generated by the ring method and the mesh method,*** machined surface profile is predicted by simulation and the parameters for the control point generation are optimized by minimizing the deviation between the predicted and the designed *** demonstrate the feasibility of the proposed tool path generation strategies,cutting tests of a two-dimensional sinewave and a micro-lens array were conducted and the results were *** a result,after tool path optimization,the peak-to-valley form error of the machined surface was reduced from 429 nm to 56 nm for the two-dimensional sinewave by using the ring method,and from 191 nm to 103 nm for the micro-lens array by using the mesh method,respectively.

关键词： ultraprecision machining diamond turning fast tool servo freeform surface tool path optimization

Frequency Gradient with Respect to Temperature for Determination of Classification of the Phase Response Curve

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Chinese Physics Letters 2013年第12期30卷 170-173页

作者： Yasuomi D.sato Department of Brain Science and Engineering Graduate School of Life Science and Systems EngineeringKyushu Institute of Technology2-4HibikinoWakamatsuKitakyushu808-0196Japan Frankfurt Institute for Advanced Studies(FIAS)Johann Wolfgang Goethe UniversityRuth-Moufang-Str.1D60438Frankfurt am MainGermany

The interesting task here is to study the frequency-current(f–I)curve and phase response curve(PRC),subject to neural temperature variations,because the f–I curve and PRC are important measurements to understand dynamical mechanisms of generation of neural oscillations,and the neural temperature is widely known to significantly affect the ***,little is discussed about how the temperature affects the f–I curve and *** this study,frequencies of the neural oscillations,modulated with the temperature variations,are quantified with an average of the *** frequency gradient with respect to temperature derived here gives clear classifications of the PRC,regardless of the *** is also indicated that frequency decreases with an increase in temperature,resulted from bifurcation switching of the saddle-homoclinic to the saddle-node on an invariant circle.

关键词： form saddle invariant

Frequency Switches at Transition Temperature in Voltage-Gated Ion Channel Dynamics of Neural Oscillators

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Chinese Physics Letters 2018年第5期35卷 152-155页

作者： Yasuomi D.sato Department of System Information Sciences Graduate School of Information Sciences Tohoku University Institute of Industrial Science University of Tokyo

Understanding of the mechanisms of neural phase transitions is crucial for clarifying cognitive processes in the brain. We investigate a neural oscillator that undergoes different bifurcation transitions from the big saddle homoclinic orbit type to the saddle node on an invariant circle type, and the saddle node on an invariant circle type to the small saddle homoclinic orbit type. The bifurcation transitions are accompanied by an increase in thermodynamic temperature that affects the voltage-gated ion channel in the neural oscillator. We show that nonlinear and thermodynamical mechanisms are responsible for different switches of the frequency in the neural oscillator. We report a dynamical role of the phase response curve in switches of the frequency, in terms of slopes of frequency-temperature curve at each bifurcation transition. Adopting the transition state theory of voltagegated ion channel dynamics, we confirm that switches of the frequency occur in the first-order phase transition temperature states and exhibit different features of their potential energy derivatives in the ion channel. Each bifurcation transition also creates a discontinuity in the Arrhenius plot used to compute the time constant of the ion channel.

关键词： Frequency Switches at Transition Temperature in Voltage-Gated Ion Channel Dynamics of Neural Oscillators

Characteristics of gas-liquid pulsed discharge plasma reactor and dye decoloration efficiency

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Journal of Environmental Sciences 2012年第5期24卷 840-845页

作者： Nyein Nyein Aye Masayuki sato Environmental Science and Engineering College Dalian Maritime University

The pulsed high-voltage discharge is a new advanced oxidation technology for water treatment. Methyl Orange （MO） dye wastewater was chosen as the target object. Some investigations were conducted on MO decoloration including the discharge characteristics of the multi-needle reactor, parameter optimization, and the degradation mechanism. The following results were obtained. The color group of the azo dye MO was effectively decomposed by water surface plasma. The decoloration rate was promoted with the increase of treatment time, peak voltage, and pulse frequency. When the initial conductivity was 1700 μS/cm, the decoloration rate was the highest. The optimum distance between the needle electrodes and the water surface was 1 mm, the distance between the grounding electrode and the water surface was 28 mm, and the number of needle electrodes and spacing between needles were 24 and 7.5 mm, respectively. The decoloration rate of MO was affected by the gas in the reactor and varied in the order oxygen 〉 air〉 argon 〉 nitrogen, and the energy yield obtained in this investigation was 0.45 g/kWh.

关键词： multi-needle plasma reactor water surface plasma decoloration efficiency Methyl Orange decoloration

POLYMER COLLOIDS FORMED BY POLYELECTROLYTE COMPLEXATION OF VINYL POLYMERS AND POLYSACCHARIDES IN AQUEOUS SOLUTION

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Chinese Journal of Polymer Science 2013年第1期31卷 39-49页

作者： Hui-dan Liu Takahiro sato Department of Macromolecular Science Osaka University

The polyelectrolyte complex formed from the polyanion and polycation was studied by turbidimetry, static and electrophoretic light scattering, and elementary analysis. Sodium salts of polyacrylate （PA） and heparin （Hep） were chosen as the polyanion, and hydrochloric salts of poly（vinyl amine）（PVA） and chitosan （Chts） as the polycation. Although these vinyl polymers and polysaccharides have remarkably different backbone chemical structures and linear charge densities, all the four combinations PA-PVA, PA-Chts, Hep-PVA, and Hep-Chts provide almost stoichiometric polyelectrolyte complexes which are slightly charged owing to the adsorption of the excess polyelectrolyte component onto the neutral complex. The charges stabilize the complex colloids in aqueous solution of a non-stoichiometric mixture, and the aggregation number of the complex colloids increases with approaching to the stoichiometric mixing ratio. The mixing ratio dependence of the aggregation number for the four complexes is explained by the model proposed in the previous study.

关键词： Polyelectrolyte complex Colloidal dispersion Polyacrylate Poly(vinyl amine) Heparin Chitosan Lightscattering.

Low friction in self-mated silicon carbide tribosystem using nanodiamond as lubricating additive in water

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Friction 2021年第3期9卷 598-611页

作者： Xudong WANG Hirotsuna sato Koshi ADACHI UniversitéParis-Saclay UVSQLISVVélizy-Villacoublay 78124France Department of Mechanical Systems Engineering Graduate School of EngineeringTohoku University6-6-01Aramaki-azaAobaAoba-kuSendai 980-8579Japan Hino Motors Ltd.3-1-1Hino-daiHino-shiTokyo 191-8660Japan

Nanodiamond particles(NDPs)have been considered as a potential lubricant additive to various tribological applications,such as water lubrication *** this study,the tribological properties of silicon carbide(SiC)lubricated by NDPs dispersed in water are investigated utilizing the ball-on-disk *** is found that the slight addition of NDP to water(i.e.,0.001 wt%)can distinctly accelerate the running-in process,which is necessary to achieve a friction coefficient(μ)as low as *** study also discusses two NDP functional terminations—hydroxyl and *** is demonstrated that the use of carboxyl-terminated NDP over a wide range of concentration(0.001 wt%-1 wt%)yields a low friction *** contrast,the ideal effective concentration of hydroxyl-terminated NDP is considerably limited because agglomeration in this material is more probable to occur than in the ***,when utilizing NDPs,the input friction energy(P_(in),defined as the product of sliding speed and applied load)is found to have an essential *** sliding tests were implemented at various P_(in) values(50-1,500 mW)using carboxyl-terminated water-dispersed *** was observed that theμand wear decreased with increasing P_(in) when 200 mW

关键词： nanodiamond particle silicon carbide(SiC) lubrication termination groups running-in driving energy

Discrete dislocation plasticity analysis of dispersion strengthening in oxide dispersion strengthened(ODS) steels

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Journal of Central South University 2014年第4期21卷 1249-1255页

作者： Akiyuki Takahashi Shota sato Department of Mechanical Engineering Faculty of Science and TechnologyTokyo University of Science

A discrete dislocation plasticity analysis of dispersion strengthening in oxide dispersion strengthened(ODS) steels was described. Parametric dislocation dynamics(PDD) simulation of the interaction between an edge dislocation and randomly distributed spherical dispersoids(Y2O3) in bcc iron was performed for measuring the influence of the dispersoid distribution on the critical resolved shear stress(CRSS). The dispersoid distribution was made using a method mimicking the Ostwald growth mechanism. Then, an edge dislocation was introduced, and was moved under a constant shear stress condition. The CRSS was extracted from the result of dislocation velocity under constant shear stress using the mobility(linear) relationship between the shear stress and the dislocation velocity. The results suggest that the dispersoid distribution gives a significant influence to the CRSS, and the influence of dislocation dipole, which forms just before finishing up the Orowan looping mechanism, is substantial in determining the CRSS, especially for the interaction with small dispersoids. Therefore, the well-known Orowan equation for determining the CRSS cannot give an accurate estimation, because the influence of the dislocation dipole in the process of the Orowan looping mechanism is not accounted for in the equation.

关键词： parametric dislocation dynamics oxide dispersion strengthened steel Orowan mechanism critical resolved shear stress dislocation dipole

Expulsion of geopressured hydrothermal system along active faults and its relation to the occurrence of earthquakes in the Shinanogawa seismic belt, Japan

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Science China Earth Sciences 2005年第2期48卷 273-281页

作者： Yasue Oki Osamu sato Research Institute for Hazards in Snowy Areas Niigata University Niigata 950-2181JapanResearch Institute for Hazards in Snowy Areas Niigata UniversityNiigata 950-2181Japan

The 1995 Northern Niigata Earthquake (M 6.0) occurred at a shallow depth in the Niigata seismic gap. The anomaly areas in temperature, electrical conductivity and Cl- concentration of groundwater trend northeast as linear distribution in the epicentral area and are approximately coincident with the area of the seismic intensity 6 (JMA scale). The distributions of seismic intensity 6 and groundwater anomalies convincingly imaged the presence of a buried active fault beneath the epicentral area. The occurrence of this earthquake and the anomalies of groundwater were related to the expulsion of geopressured hydrothermal system (GHS). All epicenters of the destructive earthquakes along the Shinanogawa seismic belt are actually located in the buried active fault zones characterized by the areas of temperature and geochemical anomalies of groundwater. These earthquakes might have been triggered by the activity of GHS. The expulsion of GHS along an active fault in combination with the thermal softening of fault zone attributed to high rock temperature may reduce fracture strength of the rock, and trigger earthquake occurrence. The dimension of the anomaly area of groundwater temperature at the epicentral area reflected the scale of the earthquake fault. The linear anomaly areas of groundwater resulting from the expulsion of GHS and having no historical destructive earthquake are of the predicated areas of future destructive earthquakes. Monitoring of groundwater conditions in these areas may provide useful information regarding the future occurrence of earthquakes.

关键词： Shinanogawa seismic belt, 1995 Northern Niigata Earthquake, geopressured hydrothermal system (GHS),buried active fault, expulsion of GHS.

Ionization of protoplanetary disks by galactic cosmic rays,solar protons,and supernova remnants

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Geoscience Frontiers 2017年第2期8卷 247-252页

作者： Ryuho Kataoka Tatsuhiko sato National Institute of Polar Research 10-3 Midori-choTachikawaTokyo190-8513Japan SOKENDAI 10-3 Midori-choTachikawaTokyo190-8513Japan Japan Atomic Energy Agency Shirakata 2-4TokaiIbaraki319-1195Japan

Galactic cosmic rays and solar protons ionize the present terrestrial atmosphere,and the air showers are simulated by well-tested Monte-Carlo simulations,such as PHITS *** use the latest version of PHITS to evaluate the possible ionization of protoplanetary disks by galactic cosmic rays（GCRs）,solar protons,and by supernova *** attenuation length of GCR ionization is updated as 118 g cm^-2,which is approximately 20% larger than the popular *** and soft possible spectra of solar protons give comparable and 20% smaller attenuation lengths compared with those from standard GCR spectra,respectively,while the attenuation length is approximately 10% larger for supernova ***,all of the attenuation lengths become 10% larger in the compound gas of cosmic abundance,e.g.128 g cm^-2 for GCRs,which can affect the minimum estimate of the size of dead zones in protoplanetary disks when the incident flux is unusually high.

关键词： Galactic cosmic rays Solar protons Supernova remnants Young Sun Protoplanetary disk T Tauri stars