THE BIMA PROJECT: O-C DIAGRAMS OF ECLIPSING BINARY SYSTEMS

HAANS, G.K.,RAMADHAN, D.G.,AKHYAR, S.,AZALIAH, R.,SUHERLI, J.,IRAWATI, P.,SAROTSAKULCHAI, T.,ARIFIN, Z.M.,RICHICHI, A.,MALASAN, H.L.,SOONTHORNTHUM, B. The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

The Eclipsing Binaries Minima (BIMA) Monitoring Project is a CCD-based photometric observational program initiated by Bosscha Observatory - Lembang, Indonesia in June 2012. Since December 2012 the National Astronomical Research Institute of Thailand (NARIT) has joined the BIMA Project as the main partner. This project aims to build an open-database of eclipsing binary minima and to establish the orbital period of each system and its variations. The project is conducted on the basis of multisite monitoring observations of eclipsing binaries with magnitudes less than 19 mag. Differential photometry methods have been applied throughout the observations. Data reduction was performed using IRAF. The observations were carried out in BVRI bands using three different small telescopes situated in Indonesia, Thailand, and Chile. Computer programs have been developed for calculating the time of minima. To date, more than 140 eclipsing binaries have been observed. From them 71 minima have been determined. We present and discuss the O-C diagrams for some eclipsing binary systems.

EXPANSION VELOCITY AND SPECTROSCOPIC CLASSIFICATION OF NOVA DELPHINI 2013

AZALIAH, RHISA,MALASAN, HAKIM L.,HAANS, GABRIELA K.,AKHYAR, SAEFUL The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

Low resolution spectra of Nova Delphini 2013 (V339 Del) in the optical range have been obtained at Bosscha Observatory, Indonesia during its maximum light (V = 4.3). Spectra were observed from August 16 to 27, 2013. The GAO-ITB RTS 20.3 cm telescope, and SBIG DSS-7 spectrograph and SBIG ST-7 XE as the detector have been employed throughout the observations. The spectra show P-Cygni profiles in Balmer, NaI'D' and Fe II lines, from which we determined shell expansion velocities of $1421.66{\pm}39.18km/s$, $1227.54{\pm}21.57km/s$ and 1402.86 km/s, respectively. Our spectroscopic observations followed the spectral evolution of V339 Del from the pre-maximum phase to early Orion phase. The characteristics of the nova Delphini 2013 resembles those of Fe II-type novae.

On the Fourier–Jacobi model for some endoscopic Arthur packet of U(3) × U(3) : the nongeneric case

Mathematical Sciences Publishers 2017 Pacific journal of mathematics Vol.286 No.1

Comparison of Predicted Acoustics with the Measured Acoustic Properties of a Multi-Purpose Hall

Haan, Chan-Hoon The Acoustical Society of Korea 2006 韓國音響學會誌 Vol.25 No.e3

The present study presents the design procedures and the acoustic properties of the main hall of Ansan Cultural Arts Center in Korea which has opened in 2004. The acoustic design values are compared with the measured acoustic properties of the completed multi-purpose hall. Acoustic design criteria were suggested in the design stage through the 3-dimentional computer simulations. The acoustic parameters including SPL, RT, C80, $D_{50}$M, RASTI were measured in the hall after completed. Acoustic measurements were carried out in the 40 measurement points using MLS sound source signal in 4 different sound source points. The results show the even distribution of sound levels within the 2.0dB of difference among all seats. The reverberation time of 1.66sec was measured which is similar to the objective value of 1.65 sec in empty states. It was also found that average C80 values lie in the objective extents of C80 from -1 to 3dB and average D50 value of 54 was measured. Thus, it is concluded that the hall can be used as a multi-purpose hall with a suitable acoustic conditions.

교회규모에 따른 음향성능 조사분석

한찬훈,이세나,이환희 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.1

In planning churches, not only the size and shape but also the acoustical environment of room are important. The church services are normally made by sound and visual activities and, especially as for modern protestant churches, the importance of the annual environment gets bigger. Meanwhile, the present study investigates the architectural specifications and room acoustic properties of several churches which have different size and shape, and compares the acoustic properties of church halls. And alternative solution were suggested to improve acoustic performance. The data occupied during the study can be used in the acoustic planning of church. In this study, architectural data such as room measures, finish material, volume and reverberation time were gathered from different five churches. Though the computer simulations sound pressure level(SPL), reverberation time(RT), clarity(C80), definition(D50), rapid sound transmission index(RASTI) of each church halls were calculated and analyzed to compare the acoustic characteristics. Through the analyses some proper design were considered with respect to size and shape. Normally, it was found that big churches have tendency of low sound pressure level and long reverberation time, but the material and shape tended to give change on SPL and RT. And it is found that large churches need to have support of electrical PA system as well as acoustical planning through architectural shape and material.

Calcium Current in the Unfertilized Egg of the Hamster

Haan, Jae-Hee,Cho, Soo-Wan,Yang, Young-Sun,Park, Young-Geun,Park, Hong-Gi,Chang, Gyeong-Jae,Kim, Yang-Mi,Park, Choon-Ok,Hong, Seong-Geun The Korean Physiological Society 1994 대한생리학회지 Vol.28 No.2

The presence of a calcium current $(i_{Ca^{2+}})$ passed via a specific channel was examined in the unfertilized hamster egg using the whole-cell voltage clamp technique. Pure inward current was isolated using a $Ca^{2+}-rich$ pipette solution containing 10 mM TEA. This current was independent of external $Na^+$ and was highly sensitive to the $Ca^{2+}$ concentration in the bathing solution, indicating that the inward current is carried by $Ca^{2+}$. The maximal amplitude was $-4.12{\pm}0.58nA\;(n=12)$ with 10mM $Ca^{2+}$ at -3OmV from a holding potential of -8OmV. This current reached its maximum within 20ms beyond -3OmV and decayed rapidly with an inactivation time constant $({\tau})$ of 15ms. Activation and inactivation of this $i_{Ca^{2+}}$ was steeply dependent on the membrane potential. The $i_{Ca^{2+}}$ began to activate at the lower voltage of -55 mV and reached its peak at -35 mV, being completely inactivated at potentials more positive than -40 mV. These result suggest that $i_{Ca^{2+}}$ in hamster eggs passes through channels with electrical properties similar to low voltage-activated T-type channels. Other results from the present study support this suggestion; First, the inhibitory effect of $Ni^{2+}\;(IC_{50}=13.7\;{\mu}M)$ was more potent than $Cd^{2+}\;(IC_{50}=123\;{\mu}M)$. Second, $Ba^{2+}$ conductance was equal to or below that of $Ca^{2+}$. Third, $i_{Ca^{2+}}$ in hamster eggs was relatively insensitive to nifedipine $(IC_{50}=96.6\;{\mu}M)$, known to be a specific t-type blocker. The physiological role of $i_{Ca^{2+}}$ in the unfertilized hamster eggs remains unclear. Analysis from steady-state inactivation activation curves reveals that only a small amount of this current will pass in the voltage range $(-70{\sim}-30\;mV)$ which partially overlaps with the resting membrane potential. This current has the property that it can be easily activated by a weak depolarization, thus it may trigger a certain kind of a intracellular event following fertilization which may cause oscillations in the membrane potential.

실표면의 확산성이 실내음향에 미치는 영향에 관한 실험적 연구

한찬훈,박계균 충북대학교 건설기술연구소 2000 建設技術論文集 Vol.19 No.1

Many acoustical criteria have been developed and presented in order to investigate the acoustic quality. Among acoustical criteria diffusion has been regarded to be very useful to evaluate overall acoustic quality of halls. It is a general fact that diffusion is needed for good acoustics of a room however, investigation on the diffusion has been inadequate due to the technical difficulties in measurements. The present study is the first step to quantify the sound diffusion in rooms by a series of experiments. The present work is a pilot study to investigate the influence of the diffusivity of interior surface on the room acoustics. Based on the results of the computer simulation, the influence of surface diffusivity on real halls was investigated. Two halls which have different diffusivities with similar volume and interior finishing materials were selected and used for field measurements. Sound pressure level and reverberation time were measured at the eight receiver points in each proposed hall. Also, the same acoustical parameters at each point in the two measured halls were calculated using computer simulation as a pilot survey. As the results, it were found that the more a hall have diffused surface, the more reverberation time was acquired. Especially it was shown that higher RT and SPL were measured in the area near lateral wall rather than the central area of halls. This means that the amounts of early reflection which makes good acoustics is increased based on the states of surface diffusivity. Also, it was found that higher sound preassure levels were acquired when more diffusion were applied to room surfaces. It is because diffusion causes the long stay of sound in rooms.

카페의 실내음향성능 조사 및 분석

한찬훈, 덜진수렝 충북대학교 건설기술연구소 2022 建設技術論文集 Vol.41 No.1

본문참고

Development of an active gust generation mechanism on a wind tunnel for wind engineering and industrial aerodynamics applications

Haan, Fred L. Jr.,Sarkar, Partha P.,Spencer-Berger, Nicholas J. Techno-Press 2006 Wind and Structures, An International Journal (WAS Vol.9 No.5

A combination Aerodynamic/Atmospheric Boundary Layer (AABL) Wind and Gust Tunnel with a unique active gust generation capability has been developed for wind engineering and industrial aerodynamics applications. This facility is a cornerstone component of the Wind Simulation and Testing (WiST) Laboratory of the Department of Aerospace Engineering at Iowa State University (ISU). The AABL Wind and Gust tunnel is primarily a closed-circuit tunnel that can be also operated in open-return mode. It is designed to accommodate two test sections ($2.44m{\times}1.83m$ and $2.44m{\times}2.21m$) with a maximum wind speed capability of 53 m/s. The gust generator is capable of producing non-stationary gust magnitudes around 27% of the mean flow speed. This paper describes the motivation for developing this gust generator and the work related to its design and testing.

표면의 확산성이 실내음장에 미치는 영향

한찬훈 충북대학교 건설기술연구소 1998 建設技術論文集 Vol.17 No.2

The relationship between the diffusion of sound and the acoustics of halls is discussed. In particular, the correlation between the diffusivity of interior surfaces and the acoustic quality of halls is investigated. In order to investigate the effect of surface diffusivity on the acoustics of halls, four imaged halls were introduced which have different degree of diffusivity on interior surfaces. Ray-tracing program (ODEON) was used for simulate the acoustic environment of the four halls, The acoustic measures such as RT, EDT, C80, RASTI were calculated at each receiver point. Through the analyses, it is found that the halls with high diffusivity have longer reverberation time due to the larger surface area but, reversely, have shorter early decay time. This represent that, in highly diffused halls, the large amount of sound energy was concentrated and distributed into halls during early time stage. Though the clarity index(C80) was relatively low in highly diffused halls due to the longer reverberation, RASTI was higher than the halls with low diffusivity. It was also revealed that the diffused walls are more effective on increasing EDT and clarity than ceiling. Finally, this paper shows the possibility of the pilot survey of acoustical simulation which can be applied to the investigation of the influence of architectural parameters on the acoustic quality of halls.