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Applied Mathematics 2016年第9期7卷 819-823页

作者： takaaki Shirahata Kagawa School of Pharmaceutical Sciences Tokushima Bunri University Sanuki Japan

Electrosensory pyramidal neurons in weakly electric fish can generate burst firing. Based on the Hodgkin-Huxley scheme, a previous study has developed a mathematical model that reproduces this burst firing. This model is called the ghostbursting model and is described by a system of non-linear ordinary differential equations. Although the dynamic state of this model is a quiescent state during low levels of electrical stimulation, an increase in the level of electrical stimulation transforms the dynamic state first into a repetitive spiking state and finally into a burst firing state. The present study performed computer simulation analysis of the ghostbursting model to evaluate the sensitivity of the three dynamic states of the model (i.e., the quiescent, repetitive spiking, and burst firing states) to variations in sodium and potassium conductance values of the model. The present numerical simulation analysis revealed the sensitivity of the electrical stimulation threshold required for eliciting the burst firing state to variations in the values of four ionic conductances (i.e., somatic sodium, dendritic sodium, somatic potassium, and dendritic potassium conductances) in the ghostbursting model.

关键词： Mathematical Model Computer Simulation Ghostbursting Ionic Conductance

Preparation of HCl Gas Sorbent from Paper Sludge

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Natural Resources 2017年第4期8卷 291-299页

作者： takaaki Wajima Department of Urban Environment Systems Chiba University Chiba Japan

Paper sludge (PS) is generated as an industrial waste during the manufacture of recycled paper products, and amounts discharged globally are increasing annually. On the other hands, hydrogen chloride (HCl) is an acidic pollutant that is present in the flue gases of most municipal and hazardous waste incinerators. In this study, the removal of hydrogen chloride gas using the product from paper sludge at high temperatures (700oC) using a fixed-bed flow-type reactor was investigated. PS can be granulated with distilled water using granulators, and the particle shapes can be kept after calcination and alkali reaction. Calcined PS and the product after alkali reaction of calcined PS have amorphous phases and katoite (Ca3Al2(SiO4)(OH)8) phase, respectively, and both of these indicate HCl removal ability at high temperature (700oC). The product from calcined PS via alkali reaction has higher HCl fixation ability (78 mg/g) than calcined PS. Removal experiments for HCl gas showed that the removal process followed pseudo-second-order kinetics rather than pseudo-first-order kinetics. These results suggested that the product particles with HCl gas removal ability at high temperature can be prepared from PS using calcination and alkali reaction.

关键词： Paper Sludge Hydrogen Chloride Gas Granulation Katoite High Temperature

Alkali Fusion Synthesis of Zeolitic Materials from Waste Dehydrated Cake Discharged from Recycling of Construction Waste Soil

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Natural Resources 2017年第4期8卷 300-305页

作者： takaaki Wajima Department of Urban Environment Systems Chiba University Chiba Japan

An inorganic cation exchanger, zeolitic material, was synthesized from dehydrated cake, which was discharged from recycling of construction waste soil, using the alkali fusion method. The waste clay was mixed with NaOH powder (the weight ratio of NaOH/waste clay = 1.0) and then heated at 300°C for 1 h to make a fused material. This fused material was then added to distilled water, and then heated at 90°C, 120°C, 150°C and 180°C for 12 h in reaction bombs under autogenous pressure in order to synthesize the cation exchanger. As a result, waste cake can be converted into fused material with high solubility, and zeolitic materials can be synthesized from the fused material. A mixture of zeolite-X and hydroxysodalite was synthesized at 90°C and 120°C, hydroxysodalite alone was synthesized at 150°C and 180°C. By increasing the synthesis temperature, the cation exchange capacity (CEC) of the product decreased, and the highest CEC of the product at 90°C, including zeolite-X, was 2.06 mmol/g, which is 64.3% of commercial zeolite-13X (3.2 mmol/g).

关键词： Waste Clay Alkali Fusion Zeolite-X Hydroxysodalite Cation Exchange Capacity

Evaluation of Kinetic Properties of Dendritic Potassium Current in Ghostbursting Model of Electrosensory Neurons

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Applied Mathematics 2015年第1期6卷 128-135页

作者： takaaki Shirahata Kagawa School of Pharmaceutical Sciences Tokushima Bunri University Sanuki Japan

A ghostbursting model is a mathematical model (a system of coupled nonlinear ordinary differential equations) that is based on the Hodgkin-Huxley formalism. The ghostbursting model describes bursting similar to the in vitro bursting of electrosensory neurons of weakly electric fish. Doiron and coworkers have focused on two system parameters of the model: maximal conductance of the dendritic potassium current and the current injected into the somatic compartment . They performed bifurcation analysis and revealed that the -parameter space was divided into three dynamical states: quiescence, periodic tonic spiking, and bursting. The present study focused on a third system parameter: the time constant of dendritic potassium current inactivation . A computer simulation of the model revealed how the dynamical states of the -parameter space changed in response to variations of .

关键词： Mathematical Model Bifurcation Ghostbursting Time Constant

Some Mathematical Properties of the Dynamically Inconsistent Bellman Equation： A Note on the Two-Sided Altruism Dynamics

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Journal of Mathematics and System Science 2015年第1期5卷 1-16页

作者： Aoki takaaki Institute of Economics Research Kyoto University

This article describes some dynamic aspects on dynastic utility incorporating two-sided altruism with an OLG setting. The special case is analyzed where the weights of two-sided altruism are dynamically inconsistent. The Bellman equation for two-sided altruism proves to be reduced to one-sided dynamic problem, but the effective discount factor is different only in the current generation. It is shown that a contraction mapping result of value function cannot be achieved in general, and that there can locally exist an infinite number of self-consistent policy functions of the class C＂ with distinct steady states （indeterminacy of self-consistent, differentiable policy functions）.

关键词： Bellman equation Two-sided altruism Dynamic inconsistency Self-consistent policy functions Indeterminacy,Overlapping generations model.

Another possibility of sonoluminescence due to the cherenkov radiation from the ZPF field in a water bubble

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Natural Science 2011年第3期3卷 249-254页

作者： takaaki Musha 不详

Sonoluminescence is the light produced from the collapse of bubbles in water under ultrasound. Schwinger proposed a physical mechanism for sonoluminescence in terms of photon production due to changes of quantum electrodynamic energy contained in a collapsing dielectric bubble. However there are critics for the Schwinger’s proposal that his estimate of the Casimir energy involved is inaccurate and there are several papers to propose its missing term. In this paper, the author presents another possible component of sonoluminescense which is due to Cherenkov radiation from tachyon pairs generated in a collapsing bubble.

关键词： Sonoluminscence Casimir Energy Cherenkov Radiation Tachyon Zero-point Energy

Numerical Simulation Analysis of a Mathematical Model of Circadian Pacemaker Neurons

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Applied Mathematics 2015年第8期6卷 1214-1219页

作者： takaaki Shirahata Kagawa School of Pharmaceutical Sciences Tokushima Bunri University Sanuki Japan

Sim and Forger have proposed a mathematical model of circadian pacemaker neurons in the suprachiasmatic nucleus (SCN). This model, which has been formulated on the Hodgkin-Huxley mo-del, is described by a system of nonlinear ordinary differential equations. An important feature of the SCN neurons observed in electrophysiological recording is spontaneous repetitive spiking, which is reproduced using this model. In the present study, numerical simulation analysis of this model was performed to evaluate variations in two system parameters of this model: the maximal conductance of calcium current (gCa) and the maximal conductance of sodium current (gNa). Simulation results revealed the spontaneous repetitive spiking states of the model in the (gCa, gNa)-pa-rameter space.

关键词： Mathematical Model Numerical Simulation Neuron Spiking

Microstructural evolution in Al-Zn eutectoid alloy by hot-rolling

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Transactions of Nonferrous Metals Society of China 2014年第7期24卷 2107-2111页

作者： Toshiaki MANAKA Goroh ITOH Yoshinobu MOTOHASHI takaaki SAKUMA School of Science and Engineering Ibaraki University College of Engineering Ibaraki University

The Al-Zn eutectoid alloy has been widely known as a typical superplastic metallic material, where fine-grained microstructure is usually obtained by heat treatment. Recently, thermo-mechanical controlled process has also been reported to provide a fine-grained microstructure. In the present study, Al-Zn alloy ingots of 20 mm in thickness were homogenized and hot-rolled to a thickness of 2 mm under three processes： 1） the specimen was air-cooled after homogenization and hot-rolled; 2） the specimen was water-quenched after homogenization and hot-rolled; 3） the specimen was immediately hot-rolled after homogenization. Microstructural observation showed that, in processes l and 3, lamellar microstructure was formed after homogenization, and became fragmented to fine-grained microstructure as the hot roiling process proceeded. In process 2, fine-grained microstructure without lamellar microstructure was attained throughout the hot-rolling process. A minimum grain size of 1.6 μm was obtained in process 3. Tensile tests at room temperature showed that the elongation to failure was the largest in process 3.

关键词： aluminum-zinc alloy eutectoid microstructure control hot-rolling superplastic material

Purcell effect of GaAs quantum dots by photonic crystal microcavities

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Chinese Optics Letters 2009年第10期7卷 879-881页

作者： Kazuaki Sakoda Takashi Kuroda NaokiI keda takaaki Mano Yoshimasa Sugimoto Tetsuyuki Ochiai Keiji Kuroda Shunsuke Ohkouchi Nobuyuki Koguchi Kiyoshi Asakawa National Institute for Materials Science Japan Graduate School of Pure and Applied Sciences University of Tsukuba NEC Corporation

We fabricate photonic crystal slab microcavities embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of the quantum dots is confirmed by the micro photoluminescence measurement. The resonance wavelengths, widths, and polarization are consistent with numerical simulation results.

关键词： GaAs Purcell effect of GaAs quantum dots by photonic crystal microcavities QDs

Balloon venoplasty for disdialysis syndrome due to pacemakerrelated superior vena cava syndrome with chylothorax postbacteraemia: A case report

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World Journal of Clinical Cases 2023年第35期11卷 8364-8371页

作者： Satomi Yamamoto Michitsugu Kamezaki Junichi Ooka Toru Mazaki Yoshiaki Shimoda takaaki Nishihara Yoko Adachi Department of Nephrology Kobe Central HospitalKobe 651-1145Japan Department of Cardiology Kobe Central HospitalKobe 651-1145Japan

BACKGROUND Although superior vena cava(SVC)syndrome has also been reported as a late complication of pacemaker(PM)implantation,acute onset of SVC syndrome caused by disdialysis syndrome in patients with PM implantation is very *** are no specific therapies or *** SUMMARY A 96-year-old woman receiving dialysis was implanted with a PM due to sick sinus *** was referred to our facility for chest discomfort experienced during *** examination,unilateral pleural effusion on the right side was cloudy with a foul *** patient was diagnosed with pyothorax and treated with *** the effusion was reduced,it gradually reaggravated and remained *** this case,SVC syndrome,which is generally considered a late complication after PM implantation,rapidly developed following the bacteraemia,resulting in impaired venous return,chylothorax,and disdialysis *** catheter intervention for SVC stenosis,the patient’s symptoms promptly *** patient has been recurrence-free for a *** Acute SVC syndrome can cause dysdialysis in PM-implanted *** intervention alone has improved this condition for a traceable period.

关键词： Superior vena cava syndrome Pacemaker implantation complications Disdialysis Case report