• The Journal of the Acoustical Society of Korea
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• v.3 no.1
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• pp.9-15
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• 1984

Thermoacoustic oscillation induced by a heater in a tube with air current is studied theoretically. Linearized perturbation equations are derived in dimensionless form under the assumption that the system is one dimensional. The equation to predict the acoustic power generation from a heating surface is derived and calculated by solving differential equations numerically. The effect of the mean velocity of the air current is illustrated. The energy conversion mechanism is shown by pressure-volume diagram like a heat engine.

• Korea-Australia Rheology Journal
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• v.14 no.1
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• pp.33-45
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• 2002

Recent results obtained for the port-pom model and the constitutive equations with time-strain separability are examined. The time-strain separability in viscoelastic systems Is not a rule derived from fundamental principles but merely a hypothesis based on experimental phenomena, stress relaxation at long times. The violation of separability in the short-time response just after a step strain is also well understood (Archer, 1999). In constitutive modeling, time-strain separability has been extensively employed because of its theoretical simplicity and practical convenience. Here we present a simple analysis that verifies this hypothesis inevitably incurs mathematical inconsistency in the viewpoint of stability. Employing an asymptotic analysis, we show that both differential and integral constitutive equations based on time-strain separability are either Hadamard-type unstable or dissipative unstable. The conclusion drawn in this study is shown to be applicable to the Doi-Edwards model (with independent alignment approximation). Hence, the Hadamardtype instability of the Doi-Edwards model results from the time-strain separability in its formulation, and its remedy may lie in the transition mechanism from Rouse to reptational relaxation supposed by Doi and Edwards. Recently in order to describe the complex rheological behavior of polymer melts with long side branches like low density polyethylene, new constitutive equations called the port-pom equations have been derived in the integral/differential form and also in the simplifled differential type by McLeish and carson on the basis of the reptation dynamics with simplifled branch structure taken into account. In this study mathematical stability analysis under short and high frequency wave disturbances has been performed for these constitutive equations. It is proved that the differential model is globally Hadamard stable, and the integral model seems stable, as long as the orientation tensor remains positive definite or the smooth strain history in the flow is previously given. However cautious attention has to be paid when one employs the simplified version of the constitutive equations without arm withdrawal, since neglecting the arm withdrawal immediately yields Hadamard instability. In the flow regime of creep shear flow where the applied constant shear stress exceeds the maximum achievable value in the steady flow curves, the constitutive equations exhibit severe instability that the solution possesses strong discontinuity at the moment of change of chain dynamics mechanisms.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.325-330
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• 2008

In order to understand the molecular mechanism of heterosis of reproduction traits in chickens, we used the quantitative real-time reverse transcriptional polymerase chain reaction (Quantitative real-time RT-PCR) technique to investigate the differential expression of estrogen receptor (ESR) and follicle stimulating hormone receptor (FSHR) genes in 32-week-old ovaries of inbred chickens and their hybrid offspring in $4{\times}4$ diallel crosses, which involved White Plymouth Rock (E), CAU Brown (D), Silkies (C) and White Leghorn (A). We found that there were significant differences in mRNA expression of ESR and FSHR genes not only between hybrids and their parental lines (p<0.01), but also among different crosses (p<0.01). Furthermore, positive correlations between differential expression of both ESR and FHSR in hybrids and heterosis percentages of 32-week-old and 42-week-old egg number traits were significant at p<0.05. Our results suggested that differential expression of ESR and FSHR genes in the ovaries of inbred chickens and their hybrids could play roles in the formation of heterosis of egg number traits to some extent.

• Journal of Information Technology Services
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• v.13 no.1
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• pp.1-21
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• 2014

In IT service quality research, the relationship between the service quality and clients' satisfaction was the focus of many studies while in relationship quality research, the influence of trust and conflict on relationship commitment seems to be the focus. In this study, these two research streams are integrated and a theoretical research model is proposed consisting of IT service quality, satisfaction, trust and relationship commitment with conflict as a moderator for the overall psychological mechanism. As satisfaction represents emotional response while trust cognitive response, this research model integrated both emotional and cognitive aspects of relationship maintenance in the IT service context. Analysis of data collected from 262 employees of global IT service firm revealed the differential effects of reliability, responsiveness, assurance and empathy on satisfaction and trust. Also, depending upon the level of conflict, the effects of reliability and assurance were found to be moderated. Further analysis revealed more profound mechanism at work relating emotional and cognitive aspects in the psychology of relationship maintenance in IT service context. Practical implications are further discussed in the conclusion.

• Journal of Korean Medical classics
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• v.24 no.5
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• pp.131-145
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• 2011

I had come at the conclusion of the development history of Disease Bi(痞病) reflected in Yi Cheon (李梴)'s work, "Euhakibmun(醫學入門)" in the respects of the causes, mechanism, symptoms, differential diagnosis and treatments. The causes of Disease Bi(痞病) mentioned at "Euhakibmun(醫學入門)" followed the Ju Dan-Gyeo(朱丹溪)'s theory. The mechanism of it went after the viewpoints of "Nae-Gyeong(內經)", Jang Jung-Gyeong(張仲景), Yi Dong-Won(李東垣) and Wang Ho-Go(王好古). The symptoms of it kept the Ju Dan-Gyeo(朱丹溪)'s theory. Yi Cheon distinguished Disease Bi(痞病) from Gyeol-Hyung(結胸) according to Jang Jung-Gyeong's theory. He knew it from abdominal dropsy(脹滿) according to Ju Dan-Gyeo's theory. He also divided it into two respects of deficiency(虛) and excessive(實) from Yi Dong-Won's viewpoint. Jang Jung-Gyeong first suggested that treatments of it could be selected according to the difference of deficiency, excessive(實), cold(寒), hot(熱), sputum(痰), fluid(飮), blood(血) and food(食). Yi Dong-Won insisted many doctors could make a mistake because they only used herbs for Gi(氣藥) instead of herbs for blood(血藥) together. Wang Ho-Go(王好古) maintained his opinion that treatments of both digestion(消導) and assistance(補益), remedies of bitter and hot herbs can recover patients from Disease Bi(痞病). Yi Cheon followed their theories properly.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.66-69
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• 1991

This paper describes a design of transducer for non-invasively detecting pressure radial pulse wave in aterial system and a recording system that for the studing the aterial pulse diagnosis of korean traditional medicine. The mechanism of transducer is composed of sensing mechanism, pressure sensor, conditioning amplifier. The variation of radial pulse pressure in the sensing mechanism is converted to the electric signal by piezo-resistive pressure sensor and it converted to the digital signal after preprocessing via A/D converter. The converted signals inputed to the computer as data files and then it display to the monitor for waveform watching and this datas can be used as the aterial pulse diagnosis data. This system effectively detect non-differential radial pulse wave and we conside that if analizing the recorded radial pulse wave, compared each other, it can be helpful in quantify radial pulse wave diagonosis of the Korean traditional medicine.

• Environmental Engineering Research
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• v.23 no.4
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• pp.442-448
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• 2018

This paper presents the numerical simulation of advection-diffusion mechanism of BOD concentration which was used as an indicator of waste only in one flow-direction of waste stabilization ponds (1-dimension (1-D)). This model was represented in partial differential equation order 2. The purpose of this paper was to determine the simulation of the model 1-D of wastewater transport phenomena based advection-diffusion mechanism and did validate the model. Numerical methods which was used for the solution of this model is finite difference method with Forward Time Central Space scheme. The simulation results which was obtained would be compared with field observation data as a validation model. Collection of field data was carried out in the Wastewater Treatment Plant Sewon, Bantul, D.I. Yogyakarta. The results of numerical simulations were indicate that the advection-diffusion mechanism takes place continuously over time. Then validation of the model was state that there was a difference between the calculation results with the field data, with a correlation value of 0.998.

• BMB Reports
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• v.35 no.4
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• pp.420-427
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• 2002

Partial nerve injury is the main cause of neuropathic pain disorders in humans. Acupuncture has long been used to relieve pain. It is known to relieve pain by controlling the activities of the autonomic nervous system. Although the mechanism of neuropathic pain and analgesic effects of electroacupuncture (EA) have been studied in a rat model system, its detailed mechanism at the molecular level remains unclear. To identify genes that might serve as either markers or explain these distinct biological functions, a cDNA microarray analysis was used to compare the expression of 8,400 genes among three sample groups. Messenger RNAs that were pooled from the spinal nerves of 7 normal. 7 neuropathic pain, and 7 EA treatment rat models were compared. Sixty-eight genes were differentially expressed more than 2-fold in the neuropathic rat model when compared to the normal, and restored to the normal expression level after the EA treatment. These genes are involved in a number of biological processes, including the signal transduction, gene expression, and nociceptive pathways. Confirmation of the differential gene expression was performed by a dot-blot analysis. Dot-blotting results showed that the opioid receptor sigma was among those genes. This indicates that opioid-signaling events are involved in neuropathic pain and the analgesic effects of EA. The potential application of these data include the identification and characterization of signaling pathways that are involved in the EA treatment, studies on the role of the opioid receptor in neuropathic pain, and further exploration on the role of selected identified genes in animal models.

• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.614-622
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• 1989

The electrochemical reduction of ${\alpha},{\beta}$-dibenzyl N-benzylidene L-aspartate in 0.1M LiCl ethanol solution was investigated by direct current (DC), differential pulse (DP) polarography, cyclic voltammetry and controlled potential coulometry(CPC). The irreversible reductive amination of imino group proceeded to form ${\alpha},{\beta}$-dibenyl N-benzyl L-aspartate by CEC or CE electrochemical reaction mechanism at the first reduction step (-0.92 volts vs. Ag-AgCl). The polarographic reduction wave was slightly suppressed due to inhibitory effect of micelle, while the irreversibility was increased according to the increase of Triton X-100 concentration. Upon the basis of product analysis and polarogram interpretation with pH change, possible CE electrode reaction mechanism was suggested.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.95-102
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• 2006

Nowadays, GPS is used widely, especially in case which needs precise position information, such as car navigation systems and various kinds of position measuring instruments in an outdoor environment. According to their applications, there are many kinds of GPS receivers with different costs and error rates. The maximum error range of the general-purpose GPS receiver is within 30m, though the error rate depends on receiving rate of signal and weather condition. RTK(Real-Time Kinematic) and DGPS(Differential Global Positioning System) have more precise accuracy than the general-purpose GPS. However end users can't afford use them because of their high price and large size of equipments. In order for the end user to obtain precise position information, it is important that GPS receivers has portability and low price. In this study, we introduce a new system that offers precise position information using the DGPS mechanism satisfying low cost and portability.