Authors:H Sekiguchi, Y Tamaki, Y Kondo, H Nakamura, K Hanashiro, K Yonemoto, T Moritani, and I Kukita
This study aimed to evaluate neuromuscular activation in the scalene and sternocleidomastoid muscles using surface electromyography (EMG) during progressively increased inspiratory flow, produced by increasing the respiratory rate under inspiratory-resistive loading using a mask ventilator. Moreover, we attempted to identify the EMG inflection point (EMGIP) on the graph, at which the root mean square (RMS) of the EMG signal values of the inspiratory muscles against the inspiratory flow velocity acceleration abruptly increases, similarly to the EMG anaerobic threshold (EMGAT) reported during incremental-resistive loading in other skeletal muscles. We measured neuromuscular activation of healthy male subjects and found that the inspiratory flow velocity increased by approximately 1.6-fold. We successfully observed an increase in RMS that corresponded to inspiratory flow acceleration with ρ ≥ 0.7 (Spearman’s rank correlation) in 17 of 27 subjects who completed the experimental protocol. To identify EMGIP, we analyzed the fitting to either a straight or non-straight line related to the increasing inspiratory flow and RMS using piecewise linear spline functions. As a result, EMGIP was identified in the scalene and sternocleidomastoid muscles of 17 subjects. We believe that the identification of EMGIP in this study infers the existence of EMGAT in inspiratory muscles. Application of surface EMG, followed by identification of EMGIP, for evaluating the neuromuscular activation of respiratory muscles may be allowed to estimate the signs of the respiratory failure, including labored respiration, objectively and non-invasively accompanied using accessory muscles in clinical respiratory care.
Authors:N. Oshima, E. Hamada, T. Suzuki, K. Kondo, I. Kanazawa, and Y. Ito
Pulsed slow positrons were produced using a time-varying moderator bias with an interval of 82 ns; 97% of the positrons were
compressed within 2 ns width at the target position. Both the positron annihilation lifetime and Doppler broadening of the
positron annihilation radiation (DBPR) of polytetrafluoroethylene (PTFE) were measured as a function of the incident energy
of slow positrons. It was shown that the lifetime and intensity of the long-lived component of positron annihilation are independent
of the positron incident energy above 1.2 keV. However, the width of the Doppler-broadened annihilation γ-ray increased in
the energy region below 1.2 keV.
Authors:Naofumi Akata, H. Kawabata, H. Hasegawa, T. Sato, Y. Chikuchi, K. Kondo, S. Hisamatsu, and J. Inaba
The atmospheric concentrations and deposition fluxes of 7Be and 210Pb were observed biweekly in Rokkasho, Japan on the Pacific Ocean coast at the northern end of Honshu Island, from March 2000
to March 2006, to clarify their regional features. Seasonal variation pattern of atmospheric 7Be concentrations had double peaks, and that of 210Pb had a single peak. Deposition fluxes of 7Be and 210Pb showed the same patterns. The total deposition pattern of 7Be was similar to that commonly seen on the Pacific Ocean side of northern Honshu Island, while the pattern of 210Pb was similar to that commonly seen on the Japan Sea side. The lack of high spine mountains windward in Rokkasho may be the
cause of this ambiguity in the winter monsoon season. Total deposition velocities and scavenging ratios of 210Pb were similar to those of 7Be from spring to fall, and showed that both nuclides had a similar removal process from the atmosphere. However, the scavenging
ratios of 210Pb were slightly larger than those of 7Be in winter, indicating different behaviors for both nuclides in the scavenging process. The scavenging ratios of both nuclides
inversely correlated with precipitation rate, and the ratios in winter were larger than in the other seasons.
Authors:N. Akata, H. Kawabata, H. Hasegawa, K. Kondo, T. Sato, Y. Chikuchi, S. Hisamatsu, and J. Inaba
Atmospheric concentrations of 210Pb change with various factors such as meso-scale meteorological conditions. We have already reported the biweekly atmospheric
210Pb concentrations in Rokkasho, Japan for 5 years and found that they had clear seasonal variations: low concentrations in
summer and high values in winter to spring. To study the reasons for the seasonal variations, the origins of the air mass
flowing to Rokkasho were analyzed by 3-D backward air mass trajectory analysis. Routes of the calculated trajectories were
classified into four regions: northeastern and southeastern Asian Continent, sea and other regions. The atmospheric 210Pb concentrations were well correlated with the frequency of the routes through the northeastern Asian Continent. A non-linear
multiple regression analysis of the 210Pb concentrations and the relative frequencies of the four routes showed good fitting of the predicted values to the observed
ones, and indicated that the atmospheric 210Pb concentrations in Rokkasho depended on the frequency of the air mass from the northeastern Asian Continent.
Authors:Ch. He, E. Hamada, T. Suzuki, H. Kobayashi, K. Kondo, V. Shantarovich, and Y. Ito
A new pulsed mono-energetic slow positron beam as well as the conventional positron annihilation lifetime spectroscopy (PALS) have been applied to study the sub-surface and the bulk of epoxy polymer. Significant changes of o-Ps parameters were found at a short distance from the surface. The lifetime of o-Ps was observed to decrease with increasing the positron implantation depth, while its intensity increased. The temperature effect on o-Ps parameters at sub-surface was also investigated. The glass transition temperature for the sub-surface was lower than that for the bulk. Furthermore, the thermal expansion coefficient of the sub-surface was found smaller than that of the bulk.
Authors:M. Numajiri, K. Masumoto, T. Miura, Y. Oki, T. Suzuki, and K. Kondo
Although the estimation of 14C radioactivity is very important from a radiation safety viewpoint at high-intensity and high-energy accelerator facilities, it is very difficult, since there is little information concerning the production cross sections by high-energy nuclear reactions. In this work, the 14C production cross section was measured for the nuclear spallation reaction of aluminum with 12-GeV protons. The chemical separation method of 14C was also studied.
Authors:H. Hasegawa, N. Akata, H. Kawabata, Y. Chikuchi, T. Sato, K. Kondo, and J. Inaba
7Be deposition fluxes and atmospheric concentrations were measured at Rokkasho Village, Aomori Prefecture, Japan, from 2000
to 2005. It was confirmed that the 7Be deposition fluxes were minimum in summer, and the fallout maximizes in winter. The atmospheric concentration of 7Be was especially low in summer, and high in the other three seasons. A positive correlation was observed between the amount
of precipitation and 7Be deposition. Clear seasonal differences were evident among the ratios of 7Be deposition flux to precipitation amounts in the four seasons. The ratios were especially high in winter, higher than those
in the other three seasons. 7Be deposition flux was estimated by a simple simulation model using atmospheric 7Be concentrations and local meteorological data. As a result, the estimated deposition value was relatively lower than the
measured value in winter.
Authors:S. Aukkaravittayapun, C. Thanachayanont, T. Theapsiri, W. Veerasai, Y. Sawada, T. Kondo, S. Tokiwa, and T. Nishide
Fluorine-doped tin dioxide
(FTO) films were deposited on silicon wafers by inverted pyrosol technique
using solutions with different doping concentration (F/Sn=0.00, 0.12, 0.75
and 2.50). The physical and electrical properties of the deposited films were
analyzed by SEM, XRF, resistivity measurement by four-point-probe method and
Hall coefficient measurement by van der Pauw method. The electrical properties
showed that the FTO film deposited using the solution with F/Sn=0.75 gave
a lowest resistivity of 3.210–4 ohm
cm. The FTO films were analyzed by temperature programmed desorption (TPD).
Evolved gases from the heated specimens were detected using a quadruple mass
analyzer for mass fragments m/z, 1(H+),
16(O+), 17(OH+ or NH3+),
18(H2O+ or NH4+),
19(F+), 20(HF+), 28(CO+
or N2+), 32(O2+),
and 152(SnO2+). The majority
of evolved gases from all FTO films were water vapor, carbon monoxide and
carbon dioxide. Fluorine (m/z 19) was detected
only in doped films and its intensity was very strong for highly-doped films
at temperature above 400C.
Authors:T. Suzuki, Y. Oki, M. Numajiri, T. Miura, K. Kondo, N. Oshima, T. Hayashi, H. Nakamura, and Y. Ito
The polymerization process of bisphenol-A dicyanate (BADCy) has been studied using a positron-annihilation lifetime technique (PAL). The polymerization was conducted at 150°C, and the process was followed by PAL. Seven kinds of samples with different curing times were also formed at 150°C, and the relation between the period of the curing time and the degree of polymerization was studied. It has been shown that theo-Ps lifetime increases in samples with a higher polymerization than 85%, which is consistent with measurements of the specific volume of BADCy.
Authors:K. Kondo, S. Ueda, Y. Chikuchi, H. Kawabata, N. Akata, H. Hasegawa, O. Mitamura, Y. Seike, and J. Inaba
Lake Obuchi is on the Shimokita Peninsula, Aomori Prefecture, Japan, near several nuclear fuel-related facilities. The lake
contains from oligohaline to polyhaline regions, and the salinity fluctuates greatly both spatially and temporally. This study
examined the possible effect of salinity on biological concentrations of 137Cs in phytoplankton on the basis of a culture experiment using stable Cs and phytoplankton species isolated from the lake.
In both Cyclotellaand Skeletonema, the biological concentrations of Cs varied with salinity conditions, and a positive linear relation was found between maximum
proliferation and biological concentrations of Cs.