2,317 research outputs found
Distribution of Caustic-Crossing Intervals for Galactic Binary-Lens Microlensing Events
Detection of caustic crossings of binary-lens gravitational microlensing
events is important because by detecting them one can obtain useful information
both about the lens and source star. In this paper, we compute the distribution
of the intervals between two successive caustic crossings, , for
Galactic bulge binary-lens events to investigate the observational strategy for
the optimal detection and resolution of caustic crossings. From this
computation, we find that the distribution is highly skewed toward short
and peaks at days. For the maximal detection
of caustic crossings, therefore, prompt initiation of followup observations for
intensive monitoring of events will be important. We estimate that under the
strategy of the current followup observations with a second caustic-crossing
preparation time of days, the fraction of events with resolvable
caustic crossing is . We find that if the followup observations can
be initiated within 1 day after the first caustic crossing by adopting more
aggressive observational strategies, the detection rate can be improved into
.Comment: total 6 pages, including 5 Figures and no Table, submitted to MNRA
Reverse Doppler Effect of Sound
We report observation of reverse Doppler effect in a double negative acoustic
metamaterial. The metamaterial exhibited negative phase velocity and positive
group velocity. The dispersion relation is such that the wavelength
corresponding to higher frequency is longer. We observed that the frequency was
down-shifted for the approaching source, and up-shifted when the source
receded
Acoustic metamaterial exhibiting four different sign combinations of density and modulus
We fabricated a double negative acoustic metamaterial which consisted of
Helmholtz resonators and membranes. Experimental data on the transmission and
dispersion relation are presented. The system exhibits three frequencies where
the acoustic state makes sharp transitions from density negative ({\rho} -NG)
to double negative (DNG), modulus negative (B-NG), and double positive (DPS) in
sequence with the frequency. We observed a wide range of negative refractive
index from -0.06 to -3.7 relative to air, which will allow for new acoustic
transformation techniques.Comment: 5 pages, 4 figures, submitted to Physical Review Letter
Quantitative Sasang Constitution Diagnosis Method for Distinguishing between Tae-eumin and Soeumin Types Based on Elasticity Measurements of the Skin of the Human Hand
The usefulness of constitutional diagnoses based on skin measurements has been established in oriental medicine. However, it is very difficult to standardize traditional diagnosis methods. According to Sasang constitutional medicine, humans can be distinguished based on properties of the skin, including its texture, roughness, hardness and elasticity. The elasticity of the skin was previously used to distinguish between people with Tae-eumin (TE) and Soeumin (SE) constitutions. The present study designed a system that uses a compression method to measure the elasticity of hand skin and evaluated its measurement repeatability. The proposed system was used to compare the skin elasticity between SE and TE subjects, which produced a measurement repeatability error of <3%. The proposed system is suitable for use as a quantitative constitution diagnosis method for distinguishing between TE and SE subjects with an acceptable level of uncertainty
Divided disk cache and SSD FTL for improving performance in storage
Although there are many efficient techniques to minimize the speed gap between processor and the memory, it remains a bottleneck for various commercial implementations. Since secondary memory technologies are much slower than main memory, it is challenging to match memory speed to the processor. Usually, hard disk drives include semiconductor caches to improve their performance. A hit in the disk cache eliminates the mechanical seek time and rotational latency. To further improve performance a divided disk cache, subdivided between metadata and data, has been proposed previously. We propose a new algorithm to apply the SSD that is flash memory-based solid state drive by applying FTL. First, this paper evaluates the performance of such a disk cache via simulations using DiskSim. Then, we perform an experiment to evaluate the performance of the proposed algorithm.clos
Probiotic properties and adsorption of Enterococcus faecalis PSCT3-7 to vermiculite
The probiotic properties of Enterococcus (E.) faecalis PSCT3-7, a new strain isolated from the intestines of pigs fed dietary fiber containing 50% sawdust, were investigated. E. faecalis PSCT3-7 tolerated a pH range of 3 to 8 and 0.3% bile salts, and it inhibited the growth of Salmonella Typhimurium in a concentration-dependent manner. In addition, E. faecalis showed resistance to several antibacterial agents. Vermiculite, a nutrient and microbial carrier, increased the bile tolerance of the strain. Scanning electron microscope images revealed good adsorption of E. faecalis PSCT3-7 onto vermiculite. E. faecalis PSCT3-7 represents a potential probiotic candidate to administer with vermiculite to swine
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