Vibration Characteristics of the PC Bridge Resonated to the Vehicles Generated by the Road Roughness Nearby the Expansion Joint

The authors performed a research using test trucks for a three-lane prestressed concrete bridge with 37.47m span that vibrated greatly. As the results of the research, the bridge had the frequency of the 1st bending vibration (ca. 3.0Hz). And also, since the frequency and that of general vehicle\u27s vibration (ca. 3.0Hz) is close, the bridge and vehicles had caused coupled vibration. Moreover it was clear that the bridge had vibrated greatly, only when the test truck had ran at the 2nd slow lane. Because vehicle\u27s suspension spring vibration had been generated by the road roughness with long space period nearby the expansion joint of the 2nd slow lane. This paper describes the vibration characteristics of the prestressed concrete bridge coupled with the vehicle\u27s vibration generated by the road roughness with long space period nearby the expansion joint. Besides, this study also examined the countermeasure to decrease the vibration by the dynamic response analysis due to running vehicle

Wavefront compensation method using novel index in holographic data storage

Photopolymer media that uses holographic data storage generally causes volume shrinkage. This volume shrinkage distorts the recorded interference fringes. We propose an adaptive optics using novel index to compensate this distortion. The SNR value is improved from 2.1 dB to 3.4 dB in the worst part of a reproduced image and the peak intensity and the full width of the half maximum of an angle are improved by 6% and 10%, respectively. These results prove that adaptive optics using this novel index worked effectively

Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers

We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and `inverted' hysteresis loops. Neither Ru-1212 nor SrRuO_3 exhibit such magnetic dynamics. The results are interpreted as evidence of the complex magnetic order in Ru-1222. We propose a specific multilayer model to explain the data, and note that superconductivity in the ruthenocuprate is compatible with both the presence and absence of the magnetic dynamics.Comment: 9 pages, 11 figures, Revtex; submitted to Phys.Rev.

Therapeutic Hypothermia Reduces Middle Cerebral Artery Flow Velocity in Patients with Severe Aneurysmal Subarachnoid Hemorrhage

Background: Transcranial Doppler (TCD) is widely used to detect and follow up cerebral vasospasm after subarachnoid hemorrhage (SAH). Therapeutic hypothermia might influence blood flow velocities assessed by TCD. The aim of the study was to evaluate the effect of hypothermia on Doppler blood flow velocity after SAH. Methods: In 20 patients treated with hypothermia (33°) due to refractory intracranial hypertension or delayed cerebral ischemia (DCI), mean flow velocity of the middle cerebral artery (MFVMCA) was assessed by TCD. Thirteen patients were treated with combined hypothermia and barbiturate coma and seven with hypothermia alone. MFVMCA was obtained within 24h before and after induction of hypothermia as well as before and after rewarming. Results: Hypothermia was induced on average 5days after SAH (range 1-12) and maintained for 144h (range 29-270). After hypothermia induction, MFVMCA decreased from 113.7±49.0 to 93.8±44.7cm/s (p=0.001). The decrease was independent of SAH-related complications and barbiturate coma. MFVMCA further decreased by 28.2cm/s between early and late hypothermia (p<0.001). This second decrease was observed in patients with DCI (p<0.001), but not in patients with intracranial hypertension (p=0.715). Compared to late hypothermia, MFVMCA remained unchanged after rewarming (65.6±32.1 vs 70.3±36.8cm/s; p=0.219). However, patients treated with hypothermia alone showed an increase in MFVMCA after rewarming (p=0.016). Conclusion: Therapeutic hypothermia after SAH decreases Doppler blood flow velocity in both intracranial hypertension and DCI cases. The results can be the effect of hypothermia-related mechanisms or resolving cerebral vasospasm during prolonged hypothermia

Compensation of hologram distortion by controlling defocus component in reference beam wavefront for angle multiplexed holograms

Holographic memory has the potential to function as a recording system with a large capacity and high data-transfer-rate. Photopolymer materials are typically used as a write-once recording medium. When holograms are recorded on this medium, they can distort due to shrinkage or expansion of the materials, which degrades the reconstructed image and causes a higher bit error rate (bER) of the reproduced data. We propose optically compensating for hologram distortion by controlling aberration components in the reference beam wavefront while reproducing data, thereby improving the reproduced data quality. First, we investigated the relation between each aberration component of the reference beam and the signal to noise ratio (SNR) of the reproduced data using numerical simulation and found that horizontal tilt and the defocus component affect the SNR. Next, we experimentally evaluated the reproduced data by controlling the defocus component in the reference beam and found that the bER of the reproduced data could be decreased by controlling the defocus center with respect to the hologram position and phase modulation depth of the defocus component. Then, we investigated a practical control method of the defocus component using an evaluation value similar to the definition of the SNR for actual data reproduction from holograms. Using a defocus controlled wavefront enabled us to decrease the bER from 3.54 x 10^-3 with a plane wave to 3.14 x 10^-4. We also investigated how to reduce the bERs of reproduced data in angle multiplexed holograms. By using a defocus controlled wavefront to compensate for hologram distortion on the 40th data page in 80-page angle multiplexed holograms, the bERs of all pages could be decreased to less than 1x10^-3. We showed that controlling the defocus component is an effective way to compensate for hologram distortion and to decrease the bER of reproduced data in holographic memory

Electrical transport and magnetic properties of nanostructured La0.67Ca0.33MnO3

Nanostructured La0.67Ca0.33MnO3 (NS-LCMO) was formed by pulsed-laser deposition on the surface of porous Al2O3. The resistance peak temperature (Tp) of the NS-LCMO increases with increasing average thickness of the films, while their Curie temperatures (Tc) remain unchanged. The coercive field of the samples increases with decreasing film thickness and its temperature dependence can be well described by Hc(T) = Hc(0)[1-(T/TB)1/2]. A large magnetoresistance and strong memory effect were observed for the NS-LCMO. The results are discussed in terms of the size effect, Coulomb blockade and magnetic tunneling effect. This work also demonstrates a new way to get nanostructured manganites

Localization by disorder in the infrared conductivity of (Y,Pr)Ba2Cu3O7 films

The ab-plane reflectivity of (Y{1-x}Prx)Ba2Cu3O7 thin films was measured in the 30-30000 cm-1 range for samples with x = 0 (Tc = 90 K), x = 0.4 (Tc = 35 K) and x = 0.5 (Tc = 19 K) as a function of temperature in the normal state. The effective charge density obtained from the integrated spectral weight decreases with increasing x. The variation is consistent with the higher dc resistivity for x = 0.4, but is one order of magnitude smaller than what would be expected for x = 0.5. In the latter sample, the conductivity is dominated at all temperatures by a large localization peak. Its magnitude increases as the temperature decreases. We relate this peak to the dc resistivity enhancement. A simple localization-by-disorder model accounts for the optical conductivity of the x = 0.5 sample.Comment: 7 pages with (4) figures include