1,518 research outputs found
Estimates of Total Factor Productivity, the Contribution of ICT, and Resource Reallocation Effects in Japan and Korea
The purpose of our study is to identify the sources of economic growth based on a KLEMS model for Japan and Korea. We also identify the growth contribution of ICT assets and resource reallocation effects in the two economies. Both Japan and Korea enjoyed high TFP growth in ICT-producing sectors but suffered low TFP growth in ICT-using sectors. For Japan, we find that the main factor underlying the Lost Decade is the slow-down in TFP growth. We also found that Korea's TFP growth was slow until the Asian financial crisis of 1997-1999 but then accelerated after the crisis. It seems that before the crisis, Korea was following a catch-up process with developed economies that was predominantly input-led and manufacturing-based, as documented by Timmer (1999) and Pyo (2001). However, through the drastic economic reform undertaken during the crisis, Korea seems to have shifted to a new phase of economic growth since the end of the 1990s. TFP growth rates, especially those in manufacturing sectors, have substantially increased in post-crisis Korea. Both in Japan and Korea, productivity in service sectors is much lower than in manufacturing. The reason probably is excessive regulation and a lack of competition in service sectors. And these factors seem to have impeded introduction of ICT in service industries. As for ICT capital accumulation, the ICT investment/GDP ratio of Korea is higher than that of Japan. Especially, the speed of ICT accumulation in the ICT sector in Korea is much faster than that in Japan. Both in Japan and Korea, the largest component in ICT investment is computing equipment. In the case of resource reallocation across sectors, the reallocation effect of capital input was negligible or negative for most periods both in Korea and Japan. After the financial crisis of 1997-99, the resource allocation effect of capital in Korea remained negative, although the size of the negative effect declined. On the other hand, the reallocation effect of labor input was positive for most periods both in Korea and Japan.
Slow dynamics near glass transitions in thin polymer films
The -process (segmental motion) of thin polystyrene films supported
on glass substrate has been investigated in a wider frequency range from
10 Hz to 10 Hz using dielectric relaxation spectroscopy and thermal
expansion spectroscopy. The relaxation rate of the -process increases
with decreasing film thickness at a given temperature above the glass
transition. This increase in the relaxation rate with decreasing film thickness
is much more enhanced near the glass transition temperature. The glass
transition temperature determined as the temperature at which the relaxation
time of the -process becomes a macroscopic time scale shows a distinct
molecular weight dependence. It is also found that the Vogel temperature has
the thickness dependence, i.e., the Vogel temperature decreases with decreasing
film thickness. The expansion coefficient of the free volume is
extracted from the temperature dependence of the relaxation time within the
free volume theory. The fragility index is also evaluated as a function of
thickness. Both and are found to decrease with decreasing film
thickness.Comment: 9 pages, 7 figures, and 2 table
Transition region of TEC enhancement phenomena during geomagnetically disturbed periods at mid-latitudes
Large-scale TEC perturbations/enhancements observed during the day sectors of major storm periods, 12-13&nbsp;February 2000, 23&nbsp;September 1999, 29&nbsp;October 2003, and 21&nbsp;November 2003, were studied using a high resolution GPS network over Japan. TEC enhancements described in the present study have large magnitudes (&ge;25&times;10<sup>16</sup> electrons/m<sup>2</sup>) compared to the quiet-time values and long periods (&ge;120 min). The sequential manner of development and the propagation of these perturbations show that they are initiated at the northern region and propagate towards the southern region of Japan, with velocities &gt;350 m/s. On 12&nbsp;February 2000, remarkably high values of TEC and background content are observed at the southern region, compared to the north, because of the poleward expansion of the equatorial anomaly crest, which is characterized by strong latitudinal gradients near 35&deg; N (26&deg; N geomagnetically). When the TEC enhancements, initiating at the north, propagate through the region 39-34&deg; N (30-25&deg; N geomagnetically), they undergo transitions characterized by a severe decrease in amplitude of TEC enhancements. This may be due to their interaction with the higher background content of the expanded anomaly crest. However, at the low-latitude region, below 34&deg; N, an increase in TEC is manifested as an enhanced ionization pattern (EIP). This could be due to the prompt penetration of the eastward electric field, which is evident from high values of the southward Interplanetary Magnetic Field component (IMF <i>B<sub>z</sub></i>) and AE index. The TEC perturbations observed on the other storm days also exhibit similar transitions, characterized by a decreasing magnitude of the perturbation component, at the region around 39-34&deg; N. In addition to this, on the other storm days, at the low-latitude region, below 34&deg; N, an increase in TEC (EIP feature) also indicates the repeatability of the above scenario. It is found that, the latitude and time at which the decrease in magnitude of the perturbation component/amplitude of the TEC enhancement are matching with the latitude and time of the appearance of the high background content. In the present study, on 12&nbsp;February 2000, the F-layer height increases at Wakkanai and Kokubunji, by exhibiting a typical dispersion feature of LSTID, or passage of an equatorward surge, which is matching with the time of occurrence of the propagating TEC perturbation component. Similarly, on 29&nbsp;October 2003, the increase in F-layer heights by more than 150km at Wakkanai and 90 km at Kokubunji around 18:00&nbsp;JST, indicates the role of the equatorward neutral wind. On that day, TEC perturbation observed at the northern region, after 18:30&nbsp;JST, which propagates towards south, could be caused mainly by the equatorward neutral wind, leading to an F-layer height increase. These observations imply the role of the equatorward neutral wind, which increases the F-layer height, by lifting the ionization to the regions of lower loss during daytime, when production is still taking place, which, in turn, increases the TEC values. <P style="line-height: 20px;"> Large-scale traveling ionospheric disturbances (LSTIDs) are considered as ionospheric manifestations of the passage of Atmospheric Gravity Waves (AGWs) that are generated at the high latitude by energy input from the magnetosphere to the low-latitude ionosphere. This study shows that large-scale TEC perturbations observed here are produced at the northern region due to the combined effects of the equatorward neutral wind, the subsequent F-layer height increase, and LSTIDs. When these perturbation components propagate through the region, 39-34&deg; N, they undergo transitions characterised by a decrease in magnitude. Also, at the low-latitude region, below 34&deg; N, an increase in the TEC exhibits EIP feature, due to the prompt penetration of the eastward electric field
A molecular dynamics simulation of polymer crystallization from oriented amorphous state
Molecular process of crystallization from an oriented amorphous state was
reproduced by molecular dynamics simulation for a realistic polyethylene model.
Initial oriented amorphous state was obtained by uniaxial drawing an isotropic
glassy state at 100 K. By the temperature jump from 100 K to 330 K, there
occurred the crystallization into the fiber structure, during the process of
which we observed the developments of various order parameters. The real space
image and its Fourier transform revealed that a hexagonally ordered domain was
initially formed, and then highly ordered crystalline state with stacked
lamellae developed after further adjustment of the relative heights of the
chains along their axes.Comment: 4 pages, 3 figure
Photoresponse of LaSrCuO nanostrip
We report the fabrication and photoresponse of 5 nm thick
LaSrCuO nanostrip with a width of 100nm. The I-V
characteristics of the nanostrip show a hysteresis and a sharp voltage jump at
. The (3K) of the nanostrip is 2.3 x 10 A/cm. The
nanostrip exhibits photoresponse signals when illuminated by a pulse laser at
1560 nm wavelength with a bias current just below . The height of the
signal reduces as the optical intensity decreases and disappears below -10 dBm.
The signal also decreases as the temperature increases, but it exists up to 30
K. These results suggest the possibility of LaSrCuO
nanostrip as single-photon detector (SSPD, SNSPD) working at high temperature
by further reducing the cross-section of the strip
Urine plasmin-like substances as an index of kidney allograft rejections.
Using solid state radioimmunoassays developed by the first author, changes in the urine level of plasmin-like substances (PLS) and fibrin degradation products (FDP) before and after human kidney transplantation were determined in 49 transplant patients. Averages of urine PLS and FDP in a normal population of 51 persons were 0.13+/-0.10 (SD) and 0.14+/-0.07 microng/ml, respectively. In all transplant patients there was an initial rise of both PLS and FDP in urine immediately after transplantation. This elevation peaked on days 4 and 5 and the PLS and FDP levels returned to normal range within 2 weeks in patients without evidence of rejeciton. A secondary rise of urine PLS was detected before or with a rise in serum creatinine in all of the patients experiencing rejections. Of 11 patients who showed a rejection episode within 2 weeks of transplantation, the secondary rise of urine PLS was detectable in 55% of the patients slightly before the serum creatinine level changes; of 6 patients with a rejection episode more than 2 weeks after transplantation, 100% showed a secondary PLS rise 6.7+/-2.3 (SE) days before the serum creatinine increased. The appearance of the secondary rise of urine FDP in the rejecting recipients was slightly later than the rise of PLS. Serial determination of urine PLS levels following human kidney transplantation appears to be an early index of rejections which occurs more than 2 weeks after transplantation, although the clinical usefulness of this measurement is probably limited
Segmental relaxation in semicrystalline polymers: a mean field model for the distribution of relaxation times in confined regimes
The effect of confinement in the segmental relaxation of polymers is
considered. On the basis of a thermodynamic model we discuss the emerging
relevance of the fast degrees of freedom in stimulating the much slower
segmental relaxation, as an effect of the constraints at the walls of the
amorphous regions. In the case that confinement is due to the presence of
crystalline domains, a quasi-poissonian distribution of local constraining
conditions is derived as a result of thermodynamic equilibrium. This implies
that the average free energy barrier for conformational
rearrangement is of the same order of the dispersion of the barrier heights,
, around . As an example, we apply the results to
the analysis of the -relaxation as observed by dielectric broad band
spectroscopy in semicrystalline poly(ethylene terephthalate) cold-crystallized
from either an isotropic or an oriented glass. It is found that in the latter
case the regions of cooperative rearrangement are significantly larger than in
the former.Comment: 10 pages, 4 figures .ep
Relationship between propagation direction of gravity waves in OH and OI airglow images and VHF radar echo occurrence during the SEEK-2 campaign
We report simultaneous observations of atmospheric gravity waves (AGW) in OI (557.7nm) and OH airglow images and VHF radar backscatter from field-aligned irregularities (FAI) in the <i>E</i>-region during the SEEK-2 (Sporadic-<i>E</i> Experiment over Kyushu 2) campaign period from 29 July to 9 August 2002. An all-sky imager was operated at Nishino-Omote (30.5 N, 130.1 E), Japan. On 14 nights, 17 AGW events were detected in OI and OH airglow images. AGW propagated mostly toward the northeast or southeast. From comparison with the <i>E</i>-region FAI occurrence, which is detected by a nearby VHF radar (31.57MHz), we found that AGW tended to propagate southeastward during FAI events. This result suggests that the interaction between AGW and <i>E</i>-region plasma plays an important role in generating FAI. Furthermore, polarization electric fields generated directly by AGW may contribute to the FAI generation.<br><br> <b>Keywords.</b> Atmospheric composition and structure (Airglow and aurora), Ionosphere (Ionospheric irregularities, Mid-latitude ionosphere
Deep-sea borehole seismological observatories in the western Pacific: temporal variation of seismic noise level and event detection
Seismological networks provide critical data for better understanding the dynamics of the Earth; however, a great limitation on existing networks is the uneven distribution of stations. In order to achieve a more uniform distribution of seismic stations, observatories must be
constructed in marine areas. The best configuration for oceanic seismic observatories is thought to be placement of seismometers in deep boreholes. Two deep-sea borehole seismological observatories (WP-1 and WP-2) were constructed in the western Pacific and form the initial
installations of a 1000 km span network. At present, seismic records of more than 400 total days were retrieved from both the WP-1 and WP-2. Long-term variations in broadband seismic noise spectra (3mHz - 10 Hz) in the western Pacific were revealed from these records, and the data showed that ambient seismic noise levels in borehole observatories are comparable to those of the quietest land seismic stations. In addition, there is little temporal variation of noise levels in
periods greater than 10 seconds. Due to this low seismic noise environment, many teleseismic events with magnitudes greater than 5 were recorded. It is confirmed that seismic observation in deep-sea borehole gives the best environment for earthquake observation in marine areas
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