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1.
Koji Ishida Ken Hirota Osamu Yamaguchi Hideki Kume Suguru Inamura Hiroki Miyamoto 《Journal of the American Ceramic Society》1994,77(5):1391-1395
In the system ZrO2 –Al2 O3 , a new method for preparing ZrO2 solid solutions from ZrCl4 and AlCl3 using hydrazine monohydrate is investigated. c -ZrO2 solid solutions containing up to ∼40 mol% Al2 O3 crystallize at low temperatures from amorphous materials. The formation mechanism is discussed from IR spectral data. The values of the lattice parameter α increase linearly from 0.5072 to 0.5105 nm with increasing Al2 O3 content. At higher temperatures, transformation of the solid solutions proceeds as follows: c ( SS ) → t ( ss ) → t ( ss ) +α-Al2 O3 → m +α-Al2 O3 . m -ZrO2 –α-Al2 O3 composite ceramics are fabricated by hot isostatic pressing for 2 h at 1250°C and 196 MPa. Microstructures and mechanical properties are examined, in connection with increasing Al2 O3 content. 相似文献
2.
Xiong Wei Wu Tomoo Yamamura Suguru Ohta Qi Xiu Zhang Fu Cong Lv Can Ming Liu Kenji Shirasaki Isamu Satoh Tatsuo Shikama Dan Lu Su Qin Liu 《Journal of Applied Electrochemistry》2011,41(10):1183-1190
The redox kinetics of VO2+/VO2 + and V3+/V2+ couples on a carbon paper (CP, HCP030 N, Shanghai Hesen, Ltd., China) electrode were investigated in terms of their standard rate constant (k 0) and reaction mechanism. The values determined for k 0 for VO2+ ?? VO2 + and V3+ ?? V2+ using the CP electrode are 1.0 × 10?3 and 1.1 × 10?3 cm s?1, respectively. The value of k 0 increases by one or two order(s) of magnitude compared with values obtained using electrodes composed of pyrolytic graphite and glassy carbon. The acceleration of the redox kinetics of vanadium ions is a result of the large surface area of the CP electrode. An inner-sphere mechanism for the reaction on the surface of the electrode is proposed. The kinetic features of vanadium redox reactions on the CP electrode reveal that CP is suitable for use as the electrodes in vanadium redox-flow batteries. 相似文献
3.
Suguru Kadomoto Kouji Izumi Atsushi Mizokami 《International journal of molecular sciences》2021,22(16)
Chemokines are a small family of cytokines that were first discovered as chemotactic factors in leukocytes during inflammation, and reports on the relationship between chemokines and cancer progression have recently been increasing. The CCL2-CCR2 axis is one of the major chemokine signaling pathways, and has various functions in tumor progression, such as increasing tumor cell proliferation and invasiveness, and creating a tumor microenvironment through increased angiogenesis and recruitment of immunosuppressive cells. This review discusses the roles of the CCL2-CCR2 axis and the tumor microenvironment in cancer progression and their future roles in cancer therapy. 相似文献
4.
5.
This paper studies the human arm's sensory‐motor control mechanism in reaching movements. First, we formulate both the kinematics and dynamics of a two‐link planar arm model with six redundant muscles. The nonlinear muscle dynamics is modeled based on several biological understandings. We then show the stability of the overall system and perform some numerical simulations. By considering the internal forces induced by the redundant muscles, we show that the damping factors in each joint can be regulated, and as the result, it can realize humanlike quasistraight line reaching movements. In addition, we also propose the gravity compensation method at the muscle input level and present the result of numerical simulation to verify the usefulness of this method. © 2005 Wiley Periodicals, Inc. 相似文献
6.
Suguru Arimoto Morio Yoshida Ji-Hun Bae 《国际自动化与计算杂志》2006,3(3):263-270
A mathematical model expressing the motion of a pair of multi-DOF robot fingers with hemi-spherical ends, grasping a 3-D rigid object with parallel fiat surfaces, is derived, together with non-holonomic constraints. By referring to the fact that humans grasp an object in the form of precision prehension, dynamically and stably by opposable forces, between the thumb and another finger (index or middle finger), a simple control signal constructed from finger-thumb opposition is proposed, and shown to realize stable grasping in a dynamic sense without using object information or external sensing (this is called "blind grasp" in this paper). The stability of grasping with force/torque balance under non-holonomic constraints is analyzed on the basis of a new concept named "stability on a manifold". Preliminary simulation results are shown to verify the validity of the theoretical results. 相似文献
7.
This article analyzes the dynamics of motion of various setups of two multiple degree‐of‐freedom (DOF) fingers that have soft tips, in fine manipulation of an object, and shows performances of their motions via computer simulation. A mathematical model of these dynamics is described as a system of nonlinear differential equations expressing motion of the overall fingers‐object system together with algebraic constraints due to tight area contacts between the finger‐tips and surfaces of the object. First, problems of (1) dynamic, stable grasping and (2) regulation of the object rotational angle by means of a setup of dual two‐DOF fingers, are treated. Second, the problem of regulating the position of the object mass center by means of a pair of two‐DOF and three‐DOF fingers is considered. Third, a set of dual three‐DOF fingers is treated, in order to let it perform a sophisticated task, which is specified by a periodic pattern of the object posture and a constant internal force. In any case, there exist sensory‐motor coordinations, which are described by analytic feedback connections from sensing to actions at finger joints. In the cases of setpoint control problems, convergences of motion to secure grasping together with the specified object rotational angle and/or the specified object mass center position, are proved theoretically. A constraint stabilization method (CSM) is used for solving numerically the differential algebraic equations to show performances of the proposed sensory‐feedback schemes. © 2002 Wiley Periodicals, Inc. 相似文献
8.
This article presents an expository work on a differential-geometric treatment of fundamental problems of 2D and 3D object grasping and manipulation by a pair of robot fingers with multi-joints under holonomic or nonholonomic constraints. First, Lagrange’s equation of motion of a fingers-object system whose motion is confined to a vertical plane is derived under holonomic constraints when rolling contacts between finger-ends and object surfaces are permitted. Then, a class of control signals called “blind grasping” and constructed without knowing the object kinematics or using any external sensing like vision or tactile sensation is shown to realize stable object grasping in a dynamic sense. Stability of motion and its convergence to an equibrium manifold are treated on the basis of differential geometry of solution trajectories of the closed-loop dynamics on the constraint manifolds. Second, a mathematical model of 3D object grasping and manipulation by a pair of multi-joint robot fingers is derived under the assumption that spinning motion of rotation around the opposing axis between contact points does no more arise. It is shown that, differently from the 2D case, the instantaneous axis of rotation of the object is time-varying, which induces a nonholonomic constraint expressed as a linear differential equation of rotational motion of the pinched object. It is shown that there is a class of control signals constructed without knowing the object kinematics or using external sensings that can realize “blind grasping” in a dynamic sense. Finally, it is shown that the proposed differential geometric treatment of stability can naturally cope with redundancy resolution problems of surplus degrees-of-freedom (d.f.) of the overall fingers-object system, which is closely related to Bernstein’s d.f. problem. 相似文献
9.
Kentaro Terashima Suguru Tamura Sea-Hoon Kim Toshinobu Yoko 《Journal of the American Ceramic Society》1997,80(11):2903-2909
The third–order nonlinear optical susceptibility, χ(3) , of lanthanide (lanthanum, praseodymium, neodymium, and samarium) borate glasses has been measured by the third harmonic generation method. The structure of the present glass system has been studied by infrared and Raman spectroscopic methods. The network structures of the present Ln2 O3 –B2 O3 glasses have been confirmed to be basically similar to each other. Praseodymium, neodymium, and samarium borate glasses exhibit χ(3) values that are larger than lanthanum borate glasses, because of the optical resonance effect, in accordance with the f – f transition. Especially, the χ(3) value for 30Pr2 O3 ·70B2 O3 glass is 1.8 × 10−12 esu, which is a factor of ∼60 larger than that of SiO2 glass. This striking enhancement of χ(3) is mainly attributed to the large transition moment to the first excitation state. 相似文献
10.
Masashi Imanaka Shigeo Tomita Suguru Kanda Mitsuteru Fujieda Kimikazu Sasa Jens Olaf Pepke Pedersen Hiroshi Kudo 《Journal of aerosol science》2010,41(5):468-474
To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using a differential mobility analyzer equipped with a Faraday cup electrometer. Using the proton beam, droplets around 10 nm in diameter were observed for both positively and negatively charged particles, but none were found when the corona discharge was used. This implies the importance of the presence of both positive and negative ions for the formation of nanosize droplets, which attract each other by Coulomb interactions, enhancing the collision frequency and leading to the formation of the 10 nm droplets. 相似文献