21,019 research outputs found
Site Response Analysis Using Forced-Vibration Tests on Hydraulic-Filled Soil Deposit
Forced vibration tests and detailed site characterization were performed at a geotechnical experimental site in Yong-jong Island where Inchon International Airport being constructed. The vibratory motions generated by the combination of hydraulic hammer compaction and dynamic compaction were monitored by 3-component velocity transducers in the down hole array as well as on the ground surface. Spectral analyses of the recorded vibratory motions were performed to evaluate the resonant frequencies of the experimental site. The linear analysis and simplified method were also performed to evaluate the resonant frequencies of the experimental site based on the results of detailed site investigation. The resonant frequencies of the experimental site evaluated by spectral analyses based on forced vibration tests were in good agreement with those of the linear analysis and the simplified method
Quantum super-cavity with atomic mirrors
We study single-photon transport in an array of coupled microcavities where
two two-level atomic systems are embedded in two separate cavities of the
array. We find that a single-photon can be totally reflected by a single
two-level system. However, two separate two-level systems can also create,
between them, single-photon quasi-bound states. Therefore, a single two-level
system in the cavity array can act as a mirror while a different type of cavity
can be formed by using two two-level systems, acting as tunable "mirrors",
inside two separate cavities in the array. In analogy with superlattices in
solid state, we call this new "cavity inside a coupled-cavity array" a
super-cavity. This supercavity is the quantum analog of Fabry-Perot
interferometers. Moreover, we show that the physical properties of this quantum
super-cavity can be adjusted by changing the frequencies of these two-level
systems.Comment: 13 pages, 9 figure
Comparison of FLUMEN and HEC-RAS 2D Models for Flash Flood Inundation in Urban Landscape
Flood inundation maps play a crucial role in preventing flood damage. Among various numerical models used to generate these maps, the fluvial modeling engine (FLUMEN) and the hydrologic engineering center’s river analysis system (HEC-RAS 2D) are particularly effective for simulating urban floods, which are influenced by complex factors such as buildings and landscapes. This study aims to examine the differences in flood analysis results that may arise from using different numerical models. This study compares the performance of FLUMEN and HEC-RAS 2D in modeling urban flash floods, characterized by local velocity variations and complex geometries. The analysis focuses on their numerical characteristics and simulation accuracy. The simulation results show that HEC-RAS 2D outperforms FLUMEN in handling turbulence, numerical stability, and peak water level predictions. These findings provide insights into the strengths and limitations of each model for urban flood management
Mechanical structure of a spin-1 particle
We investigate the mechanical structure of a spin-1 particle. Introducing
three different frameworks, i.e., the three-dimensional (3D) Breit frame, the
two-dimensional (2D) Breit frame, and the 2D infinite momentum frame
(equivalently the two-dimensional Drell-Yan frame), we scrutinize the 2D and 3D
energy-momentum tensor (EMT) distributions in these frames. We first derive the
EMT distributions in the 2D Breit frame by performing the Abel transformation.
The mass distribution in the 2D Breit frame contains an additional monopole
contribution induced geometrically. The pressure distribution in the 2D Breit
frame also gets an induced monopole structure. When the Lorentz boost is
carried out, the mass distribution in the 2D infinite-momentum frame acquires
the induced dipole term. Similarly, we also have the induced dipole
contributions to the pressure and shear-force densities. We visualize the 2D
mass distributions when the spin-1 particle is polarized along the - and
-axes. We observe that the 2D mass distribution in the infinite momentum
frame exhibit clearly the induced dipole structure when the spin-1 particle is
polarized along the -axis. We also discuss the strong force fields inside a
polarized spin-1 particle.Comment: 28 pages and 9 figure
Effects and treatment methods of acupuncture and herbal medicine for premenstrual syndrome/premenstrual dysphoric disorder: systematic review
BACKGROUND: During their reproductive years about 10% of women experience some kind of symptoms before menstruation (PMS) in a degree that affects their quality of life (QOL). Acupuncture and herbal medicine has been a recent favorable therapeutic approach. Thus we aimed to review the effects of acupuncture and herbal medicine in the past decade as a preceding research in order to further investigate the most effective Korean Medicine treatment for PMS/PMDD. METHODS: A systematic literature search was conducted using electronic databases on studies published between 2002 and 2012. Our review included randomized controlled clinical trials (RCTs) of acupuncture and herbal medicine for PMS/PMDD. Interventions include acupuncture or herbal medicine. Clinical information including statistical tests was extracted from the articles and summarized in tabular form or in the text. Study outcomes were presented as the rate of improvement (%) and/or end-of-treatment scores. RESULTS: The search yielded 19 studies. In screening the RCTs, 8 studies in acupuncture and 11 studies in herbal medicine that matched the criteria were identified. Different acupuncture techniques including traditional acupuncture, hand acupuncture and moxibustion, and traditional acupuncture technique with auricular points, have been selected for analysis. In herbal medicine, studies on Vitex Agnus castus, Hypericum perforatum, Xiao yao san, Elsholtzia splendens, Cirsium japonicum, and Gingko biloba L. were identified. Experimental groups with Acupuncture and herbal medicine treatment (all herbal medicine except Cirsium japonicum) had significantly improved results regarding PMS/PMDD. CONCLUSIONS: Limited evidence supports the efficacy of alternative medicinal interventions such as acupuncture and herbal medicine in controlling premenstrual syndrome and premenstrual dysphoric disorder. Acupuncture and herbal medicine treatments for premenstrual syndrome and premenstrual dysphoric disorder showed a 50% or better reduction of symptoms compared to the initial state. In both acupuncture and herbal medical interventions, there have been no serious adverse events reported, proving the safety of the interventions while most of the interventions provided over 50% relief of symptoms associated with PMS/PMDD. Stricter diagnostic criteria may have excluded many participants from some studies. Also, depending on the severity of symptoms, the rate of improvement in the outcomes of the studies may have greatly differed
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