Biography:

In the past J. Hasegawa has collaborated on articles with H. Nakatsuji and V. Kovalskii. One of their most recent publications is Ground and excited states of Mg porphin studied by the SAC/SAC-CI method. Which was published in journal Chemical Physics Letters.

More information about J. Hasegawa research including statistics on their citations can be found on their Copernicus Academic profile page.

J. Hasegawa's Articles: (13)

Ground and excited states of Mg porphin studied by the SAC/SAC-CI method

AbstractThe SAC (symmetry adapted cluster)/SAC-CI method is applied to the ground and excited states of magnesium porphin (MgP). The π interaction between the Mg atom and the prophin ring is small and, therefore, the essential difference between MgP and free base porphin (FBP) lies in symmetry; the former is D4h and the latter D2h. The degenerate excited states in MgP split into two in FBP. The SAC-CI results for the excitation energy and the oscillator strength compare reasonably well with the experimental spectra for Mg etioporphyrin (MgEtio) and Mg tetraphenylporphin (MgTPP) and the natures of the excited states are clarified. Gouterman's four-orbital model holds well for the Q band, but the excitations from the 2a2u MO below the four orbitals mix in the B band, as was found previously for FBP. The natures of the N bands are different between MgP and FBP.

Ground and excited states of carboxyheme: a SAC/SAC-CI study

AbstractThe SAC (symmetry adapted cluster)/SAC-CI method is applied to calculations of the ground and excited states of carboxyheme (FeC24N6OH16). The excited states are calculated up to 7.8 eV. The calculated excitation energies and oscillator strengths reproduce well the electronic spectrum. The Q bands are explained by the excitations within Gouterman's 4 orbitals. The B, N, L and M bands are explained by the excitations within ‘6 orbitals’, in which the lower porphyrin π orbitals, 44a′ and 45a′, are added to the 4 orbitals. The B band shoulder in the higher energy side has a d, σ-d∗, σ∗, CO∗ nature. The states higher than the M band are characterized by the d-π∗ and π-d∗ states; therefore, the intensities are predicted to be small.

Research paperHidden radical reactivity of the [FeO]2+ group in the H-abstraction from methane: DFT and CASPT2 supported mechanism by the example of model iron (hydro)oxide species

Highlights•The H abstraction from methane by the [FeO]2+ group in model hydroxide species was shown to proceed through oxyl transition state for all considered models.•This reveals an effect of the “hidden” first excited oxyl state FeIIIO associated with “back” electron transfer from oxygen to iron rather than by its ferryl ground state FeIVO.•The energy of the ferryl-oxyl correlates with the energy barrier of the H-abstraction from methane.

14th Congress of the Asian Society of TransplantationKidneyPreemptive Living Donor Kidney Transplantation and Kidney Function at the Initial Hospital Visit: A Single-Center Case–Control Study

Highlights•Relationship between preemptive kidney transplantation and kidney function.•Of the 30 study patients, 67% underwent preemptive kidney transplantation and 33% required dialysis before transplantation.•Time between initial visit and preemptive kidney transplantation was ∼6 months.•Creatinine levels were significantly different between the groups (P = .030).•A creatinine level >5.7 mg/dL was associated with need for dialysis before transplantation.

Time-resolved measurement of energy loss of low-energy heavy ions in a plasma using a surface-barrier charged-particle detector

AbstractWe tested an experimental setup for measurement of non-linear stopping of low-energy heavy ions in non-ideal plasmas. In this setup, we used a silicon surface-barrier charged-particle detector (SSBD), which could measure the energy of single ions. For synchronization between the plasma production and the injection of single projectiles, a fast beam kicker was installed in front of the plasma target. In order to test this setup, we used a laser-produced polyethylene plasma target instead of a shock-driven plasma device, which is under R&D process. Results of a preliminary energy loss measurement for low-speed heavy ions in the laser plasma are reported. Performance on the time resolution evaluated by using a carbon-foil target is also presented.

Development of a micro-XRF system for biological samples based on proton-induced quasimonochromatic X-rays

AbstractWe have developed a micro-XRF system based on a proton-induced quasimonochromatic X-ray (QMXR) microbeam for in vivo measurement of biological samples. A 2.5-MeV proton beam impinged normally on a Cu foil target that was slightly thicker than the proton range. The emitted QMXR behind the Cu target was focused with a polycapillary X-ray half lens. For application to analysis of wet or aquatic samples, we prepared a QMXR beam with an incident angle of 45° with respect to the horizontal plane by using a dipole magnet in order to bend the primary proton beam downward by 45°. The focal spot size of the QMXR microbeam on a horizontal sample surface was evaluated to be 250 × 350 μm by a wire scanning method. A microscope camera with a long working distance was installed perpendicular to the sample surface to identify the analyzed position on the sample. The fluorescent radiation from the sample was collected by a Si-PIN photodiode X-ray detector. Using the setup above, we were able to successfully measure the accumulation and distribution of Co in the leaves of a free-floating aquatic plant on a dilute Co solution surface.

WP.II-13 laser plasma induced from solid hydrogen for beam–plasma interaction

AbstractA solid hydrogen target has been developed for the beam–plasma interaction with a GM cycle cryo-refrigerator. The hydrogen gas was fed into the solid forming cell at a pressure of about 30 Torr, and condensed directly into crystal. The hydrogen target could be repeatedly produced every 10 min without breaking vacuum. A TEA–CO2 laser irradiated the solid hydrogen target with an intensity of 2.2×108 W/cm2 to produce a high density plasma. Optical diagnostics of a hydrogen plasma gave a maximum electron density of 2×1017 cm−3 and a maximum electron temperature of 9 eV.

Stopping of low-energy highly charged ions in dense plasmas

AbstractStopping power of low-energy, highly charged projectiles in cold dense plasmas was numerically investigated to search realistic parameters for beam–plasma interaction experiments using ≈10–100 keV/u projectiles delivered by a 1.7 MV electrostatic accelerator. In order to evaluate the energy loss, a simple Molecular Dynamics (MD) computer code was applied. If the projectile velocity was as low as the thermal velocity of plasma electrons, and the projectile charge was sufficiently high, nonlinear stopping was observed even for weakly nonideal plasma targets with Γ≈0.1. According to a numerical analysis on the charge state distribution coupled with an energy loss calculation, projectiles with such a high charge state are rapidly lost by the strong recombination owing to electrons loosely trapped by the projectile, as well as the residual hydrogen atoms in the plasma.

Experimental apparatus for the measurement of non-linear stopping of low-energy heavy ions

AbstractWe developed an experimental apparatus for the study of non-linear stopping of low-energy heavy ions in non-ideal plasmas. The target plasma was produced by an electromagnetically driven shock tube. A pair of 50-μm-diameter beam apertures was attached to the shock tube wall. These apertures confined hydrogen gas of ≈5Torr in the tube and sustained the pressure difference (∼105–106) between the tube and the beam line. In order to measure the energy loss in the plasma in the tube, we used a semiconductor charged-particle detector, which could directly measure the kinetic energy of single particles, since the beam transmission through these apertures was very small. To synchronize the plasma production in the shock tube and the injection of projectiles, a fast beam kicker was installed in front of the plasma target. Results of preliminary experiments using thin carbon foil targets showed that the measured energy loss of single projectiles after passing through the target was in agreement with other data. The time resolution of the energy-loss measurement system was ≈150ns, which is enough to measure the projectile energy loss during the life time of the target plasma.

Beam–plasma interaction experiments using electromagnetically driven shock waves

AbstractElectromagnetically driven shock tubes compatible with in-beam experiments have been developed to examine the stopping power of hot or warm matter over a wide temperature range. The beam–plasma coupling constant γ was calculated under various operating conditions of the shock tube. We found that γ∼0.1 is achievable with 10 keV/u Pb ions and a fully ionized plasma produced by a shock wave with 70–80 km/s in a hydrogen gas of 6–9 kPa. The dissociation effect on the hydrogen stopping power for low-energy protons was also evaluated and a 40–50% increase in the stopping cross-section of dissociated hydrogen was predicted in a projectile energy region of 10–40 keV. For the demonstration of the energy loss measurement using shock-heated gas targets, the developed shock tube was embedded into the beam line and tested on its shock-production abilities. In the preliminary experiment using 375 keV/u carbon projectiles, we successfully detected the signal of a carbon ion penetrating a shock-heat hydrogen target and observed a decrease in the signal height, which probably corresponds to the energy loss.

Placenta previa with early opening of the uterine isthmus is associated with high risk of bleeding during pregnancy, and massive haemorrhage during caesarean delivery

AbstractObjectiveTo demonstrate the relationship between the timing of opening of the uterine isthmus and bleeding during pregnancy and caesarean section in patients with placenta previa.MethodsA prospective observational study was conducted at a single perinatal centre. All patients with placenta previa, diagnosed between 20 and 22 weeks of gestation, who were followed up at the study hospital and underwent caesarean section were enrolled.The condition of the uterine isthmus was examined every 2 weeks. The timing (in gestational weeks) of complete opening of the uterine isthmus was determined. Patients were divided into two groups: patients in whom the uterine isthmus opened before 25 weeks of gestation (EO-previa), and patients in whom the uterine isthmus opened after 25 weeks of gestation (LO-previa). The frequency of bleeding during pregnancy and the amount of intra-operative bleeding were compared between the two groups.ResultsForty-four cases of EO-previa and 55 cases of LO-previa were analysed. Complete placenta previa at delivery was observed more frequently in the EO-previa group than in the LO-previa group (88.6% vs 47.3%, p < 0.001). An emergency caesarean section due to active bleeding was performed more frequently in the EO-previa group (48%) than in the LO-previa group (25%) (p = 0.021). The frequency of massive haemorrage (>2500 ml) during caesarean section was higher in the EO-previa group than in the LO-previa group (25% vs 9%, p = 0.033).ConclusionPlacenta previa was associated with a high risk of bleeding leading to emergency caesarean section during pregnancy, and massive haemorrhage during caesarean section in patients in whom the uterine isthmus opened before 25 weeks of gestation.

Robust Load Frequency Control

AbstractIt is highly desirable that any control system is not affected by modeling errors or parameter variations of a controlled object. This paper presents an application of a robust feedback control system to load frequency control of an interconnected power system. In the design of this control system, parameter variations in a controlled object are formulated as disturbances to the system, and then a robust compensator is introduced. This compensator makes the transfer functions between these equivalent disturbances and the controlled output exactly or approximately zero. As a result, the frequency characteristic between the reference input and the controlled output is kept almost unchanged over a specified frequency range, even if some parameters in the controlled object vary widely from their nominal values. The robust compensator is, moreover, effective in real disturbances such as load changes. The effect of the control system is demonstrated by an example applied to a two-area interconnected power system model.

Velocity Measurement of Electromagnetically-driven Shock Wave to Produce a Dissociated Hydrogen Target for Beam Interaction Experiment☆

AbstractHeavy ion fusion sciences and heavy-ion-driven high energy density physics experiments require evaluations of the stopping power with dependences on target density and temperature. We are interested in effects of dissociation of the target molecules which have not been experimentally investigated. The electro-magnetically driven shock wave has been proposed to produce well-defined dissociated target which is required to measure the stopping power with the dissociated effect. We have velocity measurements in the electro-magnetic shock tube to understand the target physical condition. The velocity measurement by laser refraction gives reliable experimental results, which shows that the shock velocity is not enough to dissociate hydrogen completely. The experiments indicate that input energy does not convert to the piston plasma in electro-magnetic shock tube efficiently.

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