• Journal of Plant Biology
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• v.32 no.4
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• pp.323-330
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• 1989

This work was carried out to elucidate effects of endogenous and exogenous IAA transport on adventitious root formation in Phaseolus vulgaris hypocotyl cuttings. For inverted or normal incubation in distilled water, the adventitious root is always formed at the morphological base but not at the morphological apex. For inverted incubation, in both distilled water and certain chemical solution, the root formation is retarded more at the first stage (0-24 hr) than at the second stage (24-48 hr). When p-chlorophenoxyisobutyric acid (PCIB) was applied to the cuttings at the first stage, theroot formation was inhibited more than at the second stage. Treatment of 2,3,5-triiodobenzoic aicd (TIBA)markedly inhibited the adventitious root formation in Phaseolus vulgaris hypocotyl cuttings. This inhibition influenced the root according to the applied stage and period. Therefore, the root formation is more related to the stage of root primordium formation than to the stage of root elongation from the primordium. Inhibition of auxin transport oraction by TIBA or PCIB could also be reversed when hypocotyl cuttings are incubated in exogenously applied IAA solution.

• The Korean Journal of Malacology
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• v.24 no.2
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• pp.97-104
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• 2008

The gonad index, reproductive cycle and first sexual maturity of Sinonovacula constricta collected from Simpo, Kimje-gun, Korea were investigated by histological analysis. The gonad index(GI) in both sexes of S. constricta increased from April and reached a maximum in July when the water temperature rapidly increased. And then, the GI values gradually decreased by spawning from August through October. Monthly variations in the GI showed a close relationship with ovarian development. The reproductive cycle in females and males can be classified into five successive stages: early active stage(March to June), late active stage(May to July), ripe stage(July to September), partially spawned stage(August to October), spent/inactive stage(October to March). The percentage of first sexual maturations in female and male clams of 50.1-60.0 mm in shell length was over 50%, and for clams over 70.1 mm in shell length, it was 100%. Because harvesting clams < 50.1 mm in shell length could potentially cause a drastic reduction in recruitment, a measure including a prohibitory fishing size should be taken for adequate improved fisheries resource management.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.78-83
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• 2012

Generally, the first stage of a launch vehicle requires high thrust to achieve a mission. We can use one high thrust level engine or a clustered engine system which made of several small thrust level engines to make high thrust. The first stage propulsion system of KSLV-II has 300tf thrust to satisfy the mission. But it is impractical to make high thrust by one engine at this moment in time. So we should cluster four 75tf class engines which can be applied to make a required thrust for the first stage propulsion system. This article deals with the concept of the first stage clustered engine arrangement of KSLV-II.

• Economic and Environmental Geology
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• v.22 no.3
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• pp.193-205
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• 1989

Regional geology of Chungil mine is composed of Cretaceous biotite granite. Chungil ore deposits are fissure filled quartz veins which developed in Cretaceous biotite granites. Mineralogic and fluid inclusion studies were undertaken to illuminate the origin of the ore deposits. Data gathered from occurrences of ore deposits and mineral paragenesis reveals that there were two major mineralization stage. The first stage is sulfides-quartz stage. The constituents of ore minerals are chalcopyrite, sphalerite, pyrrhotite with minor amount of galena, native Au, Ag, pyrite. The second stage is gangue mineral stage. Gangue minerals are quartz, fluorite and calcite. Homogenization temperature of fluid inclusions in quartz of the first and the second stage ranges from $212^{\circ}C$ to $336^{\circ}C$ and from $154^{\circ}C$ to $355^{\circ}C$ respectively. Homogenization temperature in fluorite and calcite of the second stage ranges from $127^{\circ}C$ to $252^{\circ}C$ and from $129^{\circ}C$ to $158^{\circ}C$ but these data require positive pressure corrections. Fluid inclusions in quartz of the Bongmyeong mine, Jangja the first mine and the second mine show range of homogenization temperature from $178^{\circ}C$ to $330^{\circ}C$, from $185^{\circ}C$ to $354^{\circ}C$ and from $206^{\circ}C$ to 336 respectively. The comparison of the fluid inclusion data, mineralogical component and vein attitude of the three mines with that of Chungil mine indicates that the origin of the deposits above mentioned is elucidated to be formed under similar environment. The compositions of the sphalerite in the first stage range from 16.05 mol.% FeS to 20.36 mol.% FeS.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.268-272
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• 2019

A lithium polymer battery-based 9 kJ/s high-voltage capacitor charger, which comprises two stages, is proposed. A modified LCC resonant converter and resonant circuit are introduced at the first and second stages, respectively. In the first stage, the methods for handling low-voltage and high-current batteries are considered. Delta-wye three-phase transformers are used to generate a high output voltage through the difference between the phase and line-to-line voltages. Another method is placing the series resonant capacitor of the LCC resonant components on the transformer secondary side, which conducts considerably low current compared with the transformer primary side. On the basis of the stable operation of the first charging stage, the secondary charging stage generates final output voltage by using the resonance. This additional stage protects the rectifying diodes from the negative voltage when the output capacitor is discharged for a short time. The inductance and capacitance of the resonance components are selected by considering the resonance charging time. The design procedure for each stage with the aforementioned features is suggested, and its performance is verified by not only simulation but also experimental results.

• Progress in Superconductivity and Cryogenics
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• v.12 no.2
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• pp.29-33
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• 2010

The experimental results of the 2 stage Gifford-McMahon(GM) type pulse tube refrigerator (PTR) or cryopump are presented in this paper. The objectives of his study are to develop design technology of the integral type 2 stage PTR which rotary valve is directly connected to he hot end of the regenerator and acquire its improved performance. Design of the 2 stage PTR is conducted by FZKPTR(Forschungs Zentrum Karlsruhe Pulse Tube Refrigerator) program for the design of pulse tube refrigerators. The fabricated PTR has U-type configuration and incorporates orifice valve, double-inlet valve and reservoir as phase control mechanism. Rotary valve is used to make pulsating pressure and is directly connected to inlet of $1^{st}$ stage regenerator. From experiments, cooling performance map and pressure waveform at each point were measured for different operating frequencies. Experimental results show the best cooling performance with 2 Hz operation in spite of small pressure amplitude. The lowest temperatures of the 2 stage PTR were 16.9 K at the second stage and 58.0 K at the first stage. The cooling capacities achieved were 14.4 W at 79 K, the first stage and 3.6 W at 29 K, the second stage.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.96-108
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• 1996

In this paper, we propose an object-oriented coding method in low bit-rate channels using block-based motion vectors and residual image compensation. First, we use a 2-stage algorithm for estimating motion parameters. In the first stage, coarse motion parameters are estimated by fitting block-based motion vectors and in the second stage, the estimated motion parametes are refined by the gradient method using an image reconstructed by motion vectors detected in the first stage. Local error of a 6-parameter model is compensted by blockwise motion parameter correction using residual image. Finally, model failure (MF) region is reconstructed by a fractal mapping method. Computer simulation resutls show that the proposed method gives better performance than the conventional ones in terms of th epeak signal to noise ratio (PSNR) and compression ratio (CR).

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.1
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• pp.29-41
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• 1996

The two-stage numerical model was used to study the relation between three-dimensional local wind model, advection/diffusion model of random walk method and second moment method on Pusan coastal area. The first stage is three dimensional time-dependent local wind model which gives the wind field and vertical dirrusion coefficient. The second stage is advection/diffusion model which uses the results of the first stage as input data. First, wind fields on Pusan coastal area for none synoptic scale wind showed typical land and sea breeze circulation, and convergence zone occured at 1200LST in northern of domain, in succession, moved northward of domain. Emissions from Sinpyeong industrial district were trasnported toward the inland by sea breeze during daytime, and reached the end part of domain about 1800LST. During nighttime, emissions return to sea by land breeze and vertical diffusion also contributes to upward transport. In order to use this model for forecast of air pollution concentration on the Pusan coastal area, it is necessary that computed value must be compared with measured value and wind fields model must also be dealt in detail.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.655-658
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• 1997

In this paper, we intend to develop optimized design algorithm by deciding design parameters which are considered in the first design stage of inkjet printer head. thus, the parameters are such as electric pulse, input voltage of actuator to operate actuator, shape dimension of actuator an so on. in the first design stage, according to such parameters, a lot of time and money to develop inkject printer head are needed. to reduce trial and error and to save development time in the first design stage, optimized design algorithm is required all the more. design algorithm was developed via commercial FE analysis code(ANSYS & COENTOR) for the readability and convenience of algorithm. the reasonability of algorithm was verified by implementing analysis of system stage based on the data of piezoelectric actuator which was designed through algorithm.

• The Journal of the Acoustical Society of Korea
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• v.15 no.3E
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• pp.31-36
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• 1996

In this paper, a two-stage recognition approach based on error pattern hypotheses is proposed to reduce errors of a connected digit recognizer. In the approach, a conventional recognizer is first used to produce N-best candidate strings, and then error patterns are hypothesized by examining the candidate strings. For substitution error pattern hypotheses, error-pattern-dependent classifiers having more discriminative power than the first-stage classifier are used ; and for insertion and deletion errors, word duration and energy contour information are exploited are exploited to discriminated confusing pairs. Simulation results showed that the proposed approach achieves 15% decrease in word error rate for speaker-independent Korean connected digit recognition when a hidden Markov model-based recognizer is used for the first-stage classifier.