165 research outputs found
Aqueous solution properties of pyridinium-type perfluorinated surfactants and simulation of mixture CMC
The critical micelle concentrations (CMCs) of 1,1,2,2-tetrahydroperfluoroalkylpyridinium chloride have been determined by measurements of surface tension and electrical conductivity, etc. The CMCs of perfluorinated surfactants were only about 0.02 times that of hydrocarbon one with the same carbon number. Aqueous solutions of fluorocarbon surfactants gave low surface tensions in comparison with those of hydrocarbon surfactants. The area per surfactant molecule at the airâwater interface decreased with increasing length of the fluorocarbon chain. Electromotive force measurements were made with chloride-responsive electrodes on surfactants solutions. The micelle ionization degrees decreased with increasing length of the alkyl chain. The group contribution method simulated the mixture CMCs of binary surfactants with various alkyl chain lengths. The group contribution method proved to be very useful to predict not only the mixture CMCs but also the demixing regions of binary mixtures having great differences in CMC
Automation of chamfering by an industrial robot; for the case of machined hole on a cylindrical workpiece
金沢大å¦å·¥å¦éƒ¨The study deals with the automatic chamfering for the case of a machined hole on a cylinder on the basis of CAD data, using an industrial robot. As a chamfering tool, a rotary-bar driven by an electric motor is mounted to the arm of the robot having six degrees of freedom in order to give an arbitrary position and attitude to the tool. The robot control command converted from the chamfering path is transmitted directly to the robot. From the experimental results, the system is found effective to remove a burr along the edge of a hole on a cylindrical metallic workpiece
Automation of chamfering by an industrial robot; for the case of hole on free-curved surface
金沢大å¦å·¥å¦éƒ¨The study deals with the automatic chamfering for the case of hole on free-curved surface on the basis of CAD data, using an industrial robot. As a chamfering tool, a rotary-bar driven by an electric motor is mounted to the arm of the robot having six degrees-of-freedom in order to give an arbitrary position and attitude to the tool. The robot control command converted from the chamfering path is transmitted directly to the robot. From the experimental results, the system is found effective to remove a burr along the edge of a hole on a workpiece with free-curved surface. © 2002 Elsevier Science Ltd. All rights reserved
Dynamically Integrated Transport Approach for High-Energy Nuclear Collisions at High Baryon Density
To explore the structure of the QCD phase diagram in high baryon density
domain, several high-energy nuclear collision experiments in a wide range of
beam energies are currently performed or planned using many accelerator
facilities. In these experiments search for a first-order phase transition and
the QCD critical point is one of the most important topics. To find the
signature of the phase transition, experimental data should be compared to
appropriate dynamical models which quantitatively describe the process of the
collisions. In this study we develop a new dynamical model on the basis of the
non-equilibrium hadronic transport model JAM and 3+1D hydrodynamics. We show
that the new model reproduce well the experimental beam-energy dependence of
hadron yields and particle ratio by the partial thermalization of the system in
our core-corona approach.Comment: 4 pages, 3 figures; contribution to the proceedings of the 8th
International Conference on Quarks and Nuclear Physics (QNP2018), Tsukuba,
November 13-17, 201
Dissipative Field Theory with Caldeira-Leggett Method and its Application to Disoriented Chiral Condensation
The effective field theory including the dissipative effect is developed
based on the Caldeira-Leggett theory at the classical level. After the
integration of the small field fluctuations considered as the field radiation,
the integro-differential field equation is given and shown to include the
dissipative effects. In that derivation, special cares should be taken for the
boundary condition of the integration. Application to the linear sigma model is
given, and the decay process of the chiral condensate is calculated with it,
both analytically in the linear approximation and numerically. With these
results, we discuss the stability of chiral condensates within the quenched
approximation.Comment: 16pages, ReV-Te
Phase diagram of hot and dense QCD constrained by the Statistical Model
We propose a prescription to constrain the chiral effective model approach to
the QCD phase diagram using the thermal Statistical Model, which is a
description consistent with the experimental data at the freeze-out. In the
transition region where thermal quantities of hadrons blow up, deconfined
quarks and gluons should smoothly take over the degrees of freedom from hadrons
in the Statistical Model. We use the Polyakov-loop coupled Nambu--Jona-Lasinio
(PNJL) model as an effective description in the quark side. We require that the
validity regions of these descriptions should have an overlap on the phase
diagram, which constrains model uncertainty. Our results favor a phase diagram
with the chiral phase transition located at slightly higher temperature than
deconfinement.Comment: 5 pages, 3 figures; all figures updated, results and conclusions not
modifie
Effective Model Approach to the Dense State of QCD Matter
The first-principle approach to the dense state of QCD matter, i.e. the
lattice-QCD simulation at finite baryon density, is not under theoretical
control for the moment. The effective model study based on QCD symmetries is a
practical alternative. However the model parameters that are fixed by hadronic
properties in the vacuum may have unknown dependence on the baryon chemical
potential. We propose a new prescription to constrain the effective model
parameters by the matching condition with the thermal Statistical Model. In the
transitional region where thermal quantities blow up in the Statistical Model,
deconfined quarks and gluons should smoothly take over the relevant degrees of
freedom from hadrons and resonances. We use the Polyakov-loop coupled
Nambu--Jona-Lasinio (PNJL) model as an effective description in the quark side
and show how the matching condition is satisfied by a simple ansatz on the
Polyakov loop potential. Our results favor a phase diagram with the chiral
phase transition located at slightly higher temperature than deconfinement
which stays close to the chemical freeze-out points.Comment: 8 pages, 4 figures; Talk at International Workshop on High Density
Nuclear Matter, Cape Town, South Africa, April 6-9, 201
Chiral Symmetry and Heavy-Ion Collisions
I revisit the phase structure of hot and dense matter out of quarks and
gluons with some historical consideration on the color deconfinement and chiral
phase transitions. My goal is to make clear which part of the QCD phase diagram
is under theoretical control and which part is not. I demonstrate that an
uncommon but logically possible scenario other than the standard phase diagram
cannot be ruled out. My emphasis is on the concern that one should correctly
understand what kind of phenomenon occurs associated with the phase boundary
line on the diagram. It is not quite obvious, in particular, where chiral
symmetry restoration plays a phenomenological role in the temperature and
baryon density plane except at the QCD (chiral) critical point.Comment: Plenary talk at Quark Matter 2008: 20th International Conference on
Ultra-Relativistic Nucleus Nucleus Collisions (QM 2008), Jaipur, India, 4-10
Feb 200
Spectral functions in the sigma-channel near the critical end point
Spectral functions in the -channel are investigated near the chiral
critical end point (CEP), that is, the point where the chiral phase transition
ceases to be first-ordered in the -plane of the QCD phase diagram. At
that point the meson becomes massless in spite of explicit breaking of
the chiral symmetry. It is expected that experimental signatures peculiar to
CEP can be observed through spectral changes in the presence of abnormally
light mesons. As a candidate, the invariant-mass spectrum for diphoton
emission is estimated with the chiral quark model incorporated. The results
show the characteristic shape with a peak in the low energy region, which may
serve as a signal for CEP. However, we find that the diphoton multiplicity is
highly suppressed by infrared behaviors of the meson. Experimentally,
in such a low energy region below the threshold of two pions, photons from
are major sources of the background for the signal.Comment: 12 pages, 8 figures, 1 figure replaced, minor modification
Role of hepatic STAT3 in brain-insulin action on hepatic glucose production
SummarySTAT3 regulates glucose homeostasis by suppressing the expression of gluconeogenic genes in the liver. The mechanism by which hepatic STAT3 is regulated by nutritional or hormonal status has remained unknown, however. Here, we show that an increase in the plasma insulin concentration, achieved either by glucose administration or by intravenous insulin infusion, stimulates tyrosine phosphorylation of STAT3 in the liver. This effect of insulin was mediated by the hormone's effects in the brain, and the increase in hepatic IL-6 induced by the brain-insulin action is essential for the activation of STAT3. The inhibition of hepatic glucose production and of expression of gluconeogenic genes induced by intracerebral ventricular insulin infusion was impaired in mice with liver-specific STAT3 deficiency or in mice with IL-6 deficiency. These results thus indicate that IL-6-STAT3 signaling in the liver contributes to insulin action in the brain, leading to the suppression of hepatic glucose production
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