• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.6
• /
• pp.2189-2205
• /
• 1991

Thermodynamic properties of binary nonazeotropic refrigerant mixtures are estimated by using a modified Carnhan-Starling equation of state. In this study, pure component refrigerants such as R14, R23, R13, R13 B1, R22, R12, R134a, R152a, R142b, RC318, R114, R11, R123 and R113 are chosen and the thermodynamic properties of enthalpy and entropy are calculated in terms of relevant variables. The modified Carnahan-Starling equation of state is compared with the carnahan-Staring-De Santis equation of sate. Results show that the relative errors become slightly smaller with the equation of state proposed in this study. Correlations are obtained for the mixtures of which the vapor liquid equilibruim data are available to us in the literature. Those mixtures are R14/R23, R23/R12, R13/R12, R13/R11, R13B1/R22, R13B1/RC318, R12/RC138, R12/R114 and R12/R11. The binary interaction coefficients are found under the condition of minimizing the pressure deviations at the vapor liquid equiblibrium state and the estimation of the vapor liquid equilibrium for the refrigerant mixtures is done. Pressure-enthalpy and temperature-entropy diagrams are plotted for the refrigerant mixtures of specific composition.

• Journal of Korean Ophthalmic Optics Society
• /
• v.6 no.2
• /
• pp.129-137
• /
• 2001

The proptosis of 100 healthy Korean young people was estimated. The average protrusion measured with Hertel exophthalmometer was $14.6{\pm}0.51mm$ and $13.7{\pm}0.42mm$ in the right eye, $14.2{\pm}0.46mm$ and $13.6{\pm}0.42mm$ in the left eye by two observers(A, B), and so right eye was higher than left eye. There is no significant difference of proptosis between two eyes and among the visual acuity in the man and woman. The average coefficient of variation among five measurements by two observers was 3.53% and 3.10% in the right eye, 3.32% and 3.11% in the left eye. The mean base line by two observers was $106.7{\pm}1.13mm$ and $108.4{\pm}1.08mm$ in the man, $103.4{\pm}1.23mm$ and $104.8{\pm}1.02mm$ in the woman, respectively.

• Journal of IKEEE
• /
• v.13 no.3
• /
• pp.72-79
• /
• 2009

This paper describes a compact microstrip active antenna with dual polarization. The antenna, receiving both a left-hand circularly polarized wave and a right-hand circularly polarized wave, has a function of polarization diversity. A square-shaped empty room is located on the inside of the microstrip radiator so that the size has been reduced. And slots are added around feeding point to improve input matching. Also, amplifier and switching circuitry are placed at the empty room to increase antenna gain and to select one of the circular polarizations, respectively. The proposed antenna has been applied to GPS(global positioning system). The measurement results show that it has 10dB-impedance bandwidth, 3dB axial bandwidth of about 50MHz, 3dB beamwidth of 90degree, and gain of 13dBi, respectively, for RHCP. Also, it has 3dB axial bandwidth of about 50MHz, 3dB beamwidth of 84 degree, and gain of 12dBi, respectively, for LHCP.

• Journal of the Korean Magnetics Society
• /
• v.17 no.1
• /
• pp.30-33
• /
• 2007

The $FeIn_2S_4$ exhibits an inverse spinel which Fe ions are occupied to the octahedral(B) site, while In ions are occupied to both the tetrahedral(A) and the octahedral(B) site. The $N\'{e}el$ temperature($T_N$) is determined to be 13 K. The effective moment of $FeIn_2S_4$ found to be $5.094{\mu}_B$ from the fit of Curie-Weiss inverse susceptibility for the temperature range over $T_N$, implying angular momentum contribution. The angular momentum contribution is shown in $M\"{o}ssbauer$ spectra for the antiferromagnetic ordering region($T{\leq}\;13K$), too. A weak $Fe^{2+}(B)-S^2-Fe^{2+}(B)$ interaction is responsible for a low $N\'{e}el$ temperature($T_N$) in $FeIn_2S_4$ system. The temperature dependence of electric quadrupole interaction is explained by z-axial crystalline field energy.

• Pediatric Infection and Vaccine
• /
• v.21 no.2
• /
• pp.114-120
• /
• 2014

Purpose: The objective of this study was to assess and investigate the epidemiology of pertussis in infants under 6 months of age. Methods: A prospective study was conducted between October 1, 2011 and April 30, 2013 in CHA Bundang Medical Center, Seongnam, South Korea. Polymerase chain reaction (PCR) or culture was used to detect Bordetella pertussis in nasopharyngeal aspirates from case patients who were hospitalized for acute lower respiratory tract infection (LRTI). In addition, multiplex real-time PCR assays were also performed to detect 6 etiologic viruses, including adenovirus, human metapeumo-virus, influenza virus, parainfluenza virus, respiratory syncytial virus and rhinovirus. Results: Of the 79 enrolled case patients, whose median age was 2 months of age, the most common diagnoses uncovered in this study were acute bronchiolitis (60%) and pneumonia (28%). B. pertussis infection was found in 13 cases (16%), in which 7 (53%) was coinfected with respiratory syncytial virus and 1 (7%) with influenza A virus. Of the 13 patients with B. pertussis infection, 6 (46%) were not vaccinated with the diphtheria, tetanus toxoid, and acellular pertussis vaccine, while 6 (46%) received 1 dose, and 1 (8%) received 2 doses. Conclusion: B. pertussis infection was present in 16% of under 6 month-old infants, who were hospitalized for acute LRTI. Therefore, a nationwide epidemiological surveillance of pertussis, including institutions that cater to infants under 6 months of age is necessary and needed.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.40 no.6
• /
• pp.84-89
• /
• 2003

In this paper, we real-time implemented to the TMS320C5416 the vocoder of variable bit rate applied the SOLA-B algorithm by Henja to the ITU-T G.729A vocoder of 8kbps transmission rate. This proposed method using the SOLA-B algorithm is that it is reduced the duration of the speech in encoding and is played at the speed of normal by extending the duration of the speech in decoding. At this time, we bandied that the interval of cross correlation function if skipped every 3 sample for decreasing the computational amount of SOLA-B algorithm. The real-time implemented vocoder of C.729A and SOLA-B algorithm is represented the complexity of maximum that is 10.2MIPS in encoder and 2.8MIPS in decoder of 8kbps transmission rate. Also, it is represented the complexity of maximum that is 18.5MIPS in encoder and 13.1MIPS in decoder of 6kbps, it is 18.5MIPS in encoder and 13.1MIPS in decoder of 4kbps. The used memory is about program ROM 9.7kwords, table ROM 4.5kwords, RAM 5.1 kwords. The waveform of output is showed by the result of C simulator and Bit Exact. Also, for evaluation of speech quality of the vocoder of real-time implemented variable bit rate, it is estimated the MOS score of 3.69 in 4kbps.

• 월간 기계설비
• /
• s.226
• /
• pp.92-100
• /
• 2009

• TTA Journal
• /
• s.54
• /
• pp.55-71
• /
• 1997

본 고에서는 국제표준화 기관인 ITU-T에서 진행하고 있는 ATM 기술관련 최신 동향에 대하여 기술한다. 특히 B-ISDN의 일반적인 망측면을 다루고 있는 Study Group 13의 표준화 활동에 대하여 중점적으로 설명한다.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.13.2-13.2
• /
• 2007

• TTA Journal
• /
• s.65
• /
• pp.87-103
• /
• 1999

본 고에서는 국제표준화 기관인 IUT-T에서 진행하고 있는 B-ISDN의 일반적인 망측면을 다루고 있는 Study Group 13의 표준화활동에 대하여 주요 기술현황을 설명한다.