• Journal of the Korean Chemical Society
• /
• v.20 no.2
• /
• pp.136-140
• /
• 1976

The photocyclodehydrogenation reaction of o-terphenyl type compounds has been interpreted with perturbational molecular orbital theory. Results show that the mobile bond order for the first excited state is a good reactivity index and this approach is also consistent with the orbital symmetry conservation rule of Woodward and Hoffmann.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.6
• /
• pp.3-15
• /
• 2020

For a successful construction project, the requirements of the client should be clearly defined and this should be reflected in the project based on the expertise of each project participant throughout the entire life-cycle. Therefore, it is necessary to establish the concept of Requirements Management to systematize and manage project requirements in terms of information management. This study aims to comprehensively define the concept of requirements management in the architecture industry and to provide a methodological basis for efficiently managing design requirements information by suggesting category of requirements information type and information analysis criteria. In addition, based on the case study, the requirements information was analyzed to propose a systemization methods of requirements management for PMO' design management and information management.

• Microbiology and Biotechnology Letters
• /
• v.40 no.1
• /
• pp.76-81
• /
• 2012

Removal of methane, benzene and toluene was evaluated in a lab-scale biocover packed with a soil mixture of forest soil and earthworm cast (75:25 weight ratio). The bacterial community in the biocover was characterized using quantitative real-time PCR and terminal restriction fragment length polymorphism. Methane was removed at the upper layer of the biocover (-0.1 ~ -0.4 m), where the oxygen concentration was remarkably lower. The average removal efficiencies for methane and benzene/toluene were 90% and 99%, respectively. The pmoA gene copy numbers, responsible for methane oxidation, in the upper layer were higher than those in the lower layer. While type I methanotrohs dominated the lower layer, type II methanotrophs, such as Methylocystis and Methylosinus, were noted to be predominant in the upper layer. Benzene and toluene were removed from the lower layer (-0.6 ~ -0.9 m) as well as the upper layer. Moreover, the tmoA gene copy number, responsible for benzene/toluene oxidation, seen in the upper layer was not significantly different from those seen in the lower layer. These results suggest that a biocover packed with a soil and earthworm cast mixture is a promising method which could be utilized for the control of methane and volatile organic compounds such as benzene and toluene.

• Journal of The Korean Society of Inherited Metabolic disease
• /
• v.15 no.1
• /
• pp.44-48
• /
• 2015

Mucopolysaccharidosis (MPS) IIIA is a lysosomal storage disorder caused by abnormalities of the enzyme Heparan N-sulfatase that is required for degradation of heparan sulfate. The patient in this study was a 5 year-old boy who presented with macrocephaly and developmental delay. Urinary excretion of glycosaminoglycan was increased (26 g/moL creatinine, reference range: <7 g/moL creatinine) and a distinct band of heparan sulfate was shown in electrophoresis. Heparan N-sulfatase activity was significantly decreased in skin fibroblasts (0.2 pmoL/min/mg protein, reference range: 9-64 pmoL/min/mg protein). PCR and direct sequencing analysis of the SGSH gene showed compound heterozygous mutations: c.1040C>T (p.S347F) and c.703G>A (p.D235N). This is the first report for a Korean patient with MPS IIIA who was confirmed by biochemical investigation and molecular genetic analyses.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.4 no.2 s.7
• /
• pp.73-79
• /
• 2005

Various CMOS quadrature-voltage-controlled oscillators(QVCOS) are designed and fabricated for the comparison of the phase noise characteristic. The first one is that the QVCO is composed of two Colpitts oscillators cross-coupled with PMOS coupling transistors. The second and third ones are the conventional LC VCO and the balanced Colpitts VCO followed by the frequency-divide-by-two, respectively. The simulation result demonstrate that Colpitts schemes show better phase noise performance by 6 dB than that of a conventional stheme in which LC VCO is followed by the frequency-divide-by-two.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.6
• /
• pp.32-40
• /
• 2015

In this paper, the optimum antenna placement is analyzed by considering the interference between airborne antennas mounted on the unmanned aerial vehicle(UAV). The analysis is implemented by selecting the antennas that the distance and operational frequency band between airborne antennas is close to each other among the omni-directional antennas. The analyzed antennas are the control datalink, TCAS(Traffic Collision & Avoidance System), IFF(Identification Friend or Foe), GPS(Global Positioning System), and RALT(Radar ALTimeter) antennas. There are three steps for the optimum antenna placement analysis. The first step is selecting the antenna position having the optimum properties by monitoring the variation of radiation pattern and return loss by the fuselage of UAV after selecting the initial antenna position considering the antenna use, type, and radiation pattern. The second one is analyzing the interference strength between airborne antennas considering the coupling between airborne antennas, spurious of transmitting antenna, and minimum receiving level of receiving antenna. In case of generating the interference, the antenna position without interference is selected by analyzing the minimum separation distance without interference. The last one is confirming the measure to reject the frequency interference by the frequency separation analysis between airborne antennas in case that the intereference is not rejected by the additional distance separation between airborne antennas. This analysis procedure can be efficiently used to select the optimum antenna placement without interference by predicting the interference between airborne antennas in the development stage.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.5
• /
• pp.457-461
• /
• 2014

Using $0.18{\mu}m$ CMOS process silicon neuron circuit of the pulse type for modeling biological neurons, were designed in the semiconductor integrated circuit. Neuron circuiSt providing is formed by MOS switch for initializing the input terminal of the capacitor to the input current signal, a pulse signal and an amplifier stage for generating an output voltage signal. Synapse circuit that can convert the current signal output of the input voltage signal, using a bump circuit consisting of NMOS transistors and PMOS few. Configure a chain of neurons for verification of the neuron model that provides synaptic neurons and two are connected in series, were performed SPICE simulation. Result of simulation, it was confirmed the normal operation of the synaptic transmission characteristics of the signal generation of nerve cells.

• Journal of Advanced Navigation Technology
• /
• v.26 no.2
• /
• pp.85-90
• /
• 2022

In this study, in order to test the performance of the aircraft system, a threat signal simulator that can transmit a signal similar to the actual threat to the aircraft under test with high power was designed. The high-power threat signal simulator should be able to transmit broadband (UHF band, L band, S band, X band) communication signals and radar signals, and control to transmit signals accurately directed to the aircraft through interfacing tracking radar. The signal strength of the developed equipment is 63 dBm to 93 dBm or more depending on type of signal, and the tracking precision is less than 0.1 degree, which satisfies the required performance. And it was confirmed that the antenna of the high-power threat signal simulator can accurately direct the signal to the aircraft position through the tracking radar interfacing.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.26 no.4
• /
• pp.10-20
• /
• 2022

The performance analysis test of the scramjet engine intake was conducted under the Mach 5 condition of the scramjet engine test facility, a free-jet ground test facility of the Korea Aerospace Research Institute. A pitot/static pressure rake installed at the rear of the isolator was designed and manufactured to measure the total pressure recovery rate and mass capture ratio, which are typical performance factors of the scramjet engine intake. The effect of the rake mounted at the rear of the isolator on the intake, the performance analysis measured by the rake, and the change in wall static pressure distribution according to the angle of attack were performed. Finally, the point at which the intake unstart occurred was confirmed by using the rear back pressure adjusting device, which simulates pressure rise in the combustor, and the results are summarized in this paper.

• Clean Technology
• /
• v.25 no.1
• /
• pp.91-97
• /
• 2019

Oxidative desulfurization (ODS) has received much attention in recent years because refractory sulfur compounds such as dibenzothiophenes can be oxidized selectively to their corresponding sulfoxides and sulfones, and these products can be removed by extraction and adsorption. In this work, The oxidative desulfurization of marine diesel fuel was performed in a batch reactor with hydrogen peroxide ($H_2O_2$) in the presence of various supported heteropoly acid catalysts. The catalysts were characterized by XRD, XRF, XPS and nitrogen adsorption isotherm techniques. Based on the sulfur removal efficiency of promising silica supported heteropoly acid catalysts, the ranking of catalytic activity was: $30\;H_3PW_{12}/SiO_2$ > $30\;H_3PMo_{12}/SiO_2$ > $30\;H_4SiW_{12}/SiO_2$, which appears to be related with their intrinsic acid strength. The $30\;H_3PW_{12}/SiO_2$ catalyst showed the highest initial sulfur removal efficiency of about 66% under reaction conditions of $30^{\circ}C$, $0.025g\;mL^{-1}$ (cat./oil), 1 h reaction time. However, through the recycle test of the $H_3PW_{12}/SiO_2$ catalyst, significant deactivation was observed, which was attributed to the elution of the active component $H_3PW_{12}$. By introducing cesium cation ($Cs^+$) into the $H_3PW_{12}/SiO_2$ catalyst, the stability of the catalyst was improved with changing the solubility, and the $Cs^+$ ion exchanged catalyst could be recycled for at least five times without severe elution.