• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.245-253
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• 2011

We investigate the flow characteristics of elementary-flow paths with $90^{\circ}$ bends; a velocity-control trim consists of such paths. For geometric similarity, the width and length of each path are selected, and the number of bends is 0, 4, or 8. The flow tests are conducted with the same flow-path elements. The numerical results are in good agreement with the experimental data. In elements without bends, the volume flow rate decreases with the length of the flow path, with a constant pressure drop between the inlet and the outlet. However, in flow paths with $90^{\circ}$ bends, it increases and then decreases with the length of the flow path. For a fixed number of $90^{\circ}$ bends, better pressure-drop characteristics are observed as the length of the flow path increases. For a fixed flow-path length, a flow-path element with more bends has a smoother pressure drop along the path.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.182-185
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• 2005

Satellite cameras are calibrated before launch in detail and in general, but it cannot be guaranteed that the geometry is not changing during launch and caused by thermal influence of the sun in the orbit. Modem satellite imaging systems are based on CCD-line sensors. Because of the required high sampling rate the length of used CCD-lines is limited. For reaching a sufficient swath width, some CCD-lines are combined to a longer virtual CCD-line. The images generated by the individual CCD-lines do overlap slightly and so they can be shifted in x- and y-direction in relation to a chosen reference image just based on tie points. For the alignment and difference in scale, control points are required. The resulting virtual image has only negligible errors in areas with very large difference in height caused by the difference in the location of the projection centers. Color images can be related to the joint panchromatic scenes just based on tie points. Pan-sharpened images may show only small color shifts in very mountainous areas and for moving objects. The direct sensor orientation has to be calibrated based on control points. Discrepancies in horizontal shift can only be separated from attitude discrepancies with a good three-dimensional control point distribution. For such a calibration a program based on geometric reconstruction of the sensor orientation is required. The approximations by 3D-affine transformation or direct linear transformation (DL n cannot be used. These methods do have also disadvantages for standard sensor orientation. The image orientation by geometric reconstruction can be improved by self calibration with additional parameters for the analysis and compensation of remaining systematic effects for example caused by a not linear CCD-line. The determined sensor geometry can be used for the generation? of rational polynomial coefficients, describing the sensor geometry by relations of polynomials of the ground coordinates X, Y and Z.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.105-112
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• 2003

Diode rectifier which can't be controlled output voltage and phase control converter as AC/DC converter have low power factor and harmonics of lower order in the line current. In this paper, three phase PWM(Pulse Width Modulation) AC/DC boost converter is studied to solve these problems. The characteristics of a proposed converter are to control the phase of current without current sensor as a very simple control algorithm using circuit parameters only and to apply sinusoidal PWM method with fixed switching frequency due to a difficult design of input filter and switching device. We simulate for the proposed algorithm that high power factor is achieved and DC link voltage has fast dynamic response without ripple in rectifying and regenerating operation. As a result of experiment with circuit parameter(inductor, capacitor) decided in simulation, the proposed converter had high power factor and reduction of low order harmonics as against diode rectifier.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.132-132
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• 2018

The aim of this study was to enhance the Tartary buckwheat growth and phenolic profile by the application of $SiO_2$ on potsin the glasshouse. The liquid of $SiO_2$ were applied at three times after three weeks of sowing at ten days interval. The doses of the $SiO_2$ was low (2.5 ml/5 L water), high (10 ml in 5 L water) and control experiment was done without $SiO_2$. In this study, it is clearly shown that high dose of $SiO_2$ increased the buckwheat plant growth including, plant height, leaf length and width, stem diameter, fresh weight and number of seed per plant compared to control treatment. In the same way, the total phenolic compound (1421 mg/100 g), total flavonoid (35.1 mg/100g), rutin (3,130 mg/100g) and DPPH (82%) in plant were also increased high dose of $SiO_2$ compared to control (1,175 mg/100g, 31.9mg/100g, 860 mg/100g, 59%, respectively). Moreover, higher phenolic compound (1,421 mg/100g) and DPPH (82%) was observed in plant compared to seed (196 mg/100mg, 72 %, respectively). In the contrary, total flavonoid (36.2 mg/100g) and rutin (1,400 mg/100g) was higher in buckwheat seed compared to plant (35.1 mg/100g, 3,130 mg/100g, respectively). Finally, it is concluded that higher dose of $SiO_2$ enhance buckwheat growth and phenolic profile. Further investigation is needed to evaluate the optimum dose of $SiO_2$ according to soil conditions in the field.

• Clinical and Experimental Reproductive Medicine
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• v.41 no.2
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• pp.92-95
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• 2014

Objective: This study sought to evaluate platelet volume indices (mean platelet volume [MPV], platelet distribution width [PDW], and platelet large cell ratio [P-LCR]) in varicocele patients, and compare it with platelet volume parameters in healthy controls. Methods: This cross-sectional study involved 2 groups: group 1 included 51 varicocele subjects and group 2 consisted of 50 healthy control subjects of similar ages. Peripheral venous blood samples were collected with ethylenediaminetetraacetic acid-K2 anticoagulant between 8:30 AM and 10 AM following an overnight fast. Platelet volume parameters (MPV, PDW, and P-LCR) were measured in both groups within 2 hours of sampling. Results: The mean PDW, MPV, and P-LCR were $13.9{\pm}2.5%$, $10.1{\pm}1.3fL$, and $27.3{\pm}7.8%$ in varicocele patients, respectively, and were $12.6{\pm}2.4%$, $9.3{\pm}1.1fL$, and $21.9{\pm}6.4%$ in the control group, respectively. The mean PDW, MPV, and P-LCR were significantly higher in the varicocele group than the control group. Conclusion: The results of the present study suggest that vascular components may play an important role in the pathophysiology of varicocele; therefore, there is a great need for prospective studies to confirm this relationship.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.269-276
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• 1998

In maxillary canine retraction by means of sliding mechanics, we designed MAS(molar anchoring spring) to prevent anchorage loss and uncontrolled tipping of tooth movement and have applied it in clinical cases. The anchorage control of the maxillary first molar and type of tooth movement of the maxillary canine were studied in 31 subjects. The measurements were made on cephalograms, orthopantomograms and dental casts. The obtained results were as follows. 1. In case of the maxillary first molar, there was a little sagittal anchorage loss, but there was no vertical & transverse anchorage loss. 2. In case of the maxillary canine, there was distal tipping movement and also there was a little intrusion tendency.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.2
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• pp.171-178
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• 2007

Botulinum toxin type A (BTX-A) has a local effect at the neuromuscular junction by blocking acetylcholine release and thus causing paralysis and atrophy of the affected muscles. In dentistry, Botulinum toxin type A(BTX-A) is used for the treatment of masseteric hypertrophy, temporomandibular disorder, and severe bruxism related neurologic disorder. We hypothesized that the muscle atrophy after BTX-A injection into masseter muscle in growing rats, could affect the jaw growth. The purpose of this study was to determine the effects of the BTX-A injected into the masseter muscle on the jaw growth in rats. Rats were divided into four groups(group 1; control group, group 2; saline injection group, group 3; BTX-A injection group, group 4; baseline control group). Group 4 was sacrificed at the beginning of the experiment to provide baseline values of jaw measurements. The weight, length and width of jaw in those groups were measured every weeks. This study reported that the mandibular body length, condylar length, coronoid process length, anterior region height, coronoid process height and condylar height of the jaw in BTX-A injection group were shorter than those of the control and saline injection groups(P<0.05). In conclusion, BTX-A injected into the masseter muscle may affect the undergrowth of the jaw in rats.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.94-100
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• 2012

The passive control by vertical splitter plate of fluid force acting on a square prism near a plane wall was studied by measuring of fluid force on the prism and by visualization of the flow field using PIV. The hight of the splitter plate was 10% of the square width. The experimental parameters were the attaching position of vertical splitter plate and the space ratios G/B to the prism height. Time variation of vorticity was most remarkable at 3.0B(B: prism height) position toward wake direction from the center of the prism. The point of inflection of average lift coefficient and Strouhal number on the prism were represented at the space ratio G/B=0.4~0.6 for the prism having vertical splitter plate. The drag of the prism was reduced average 5.0% with the space ratios by attaching the vertical splitter plate at the upper and rear corner on the prism. In this case, the size of the separated region on the upside of the prism was smaller than that of prism having no the splitter plate.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.305-309
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• 2013

A freesia (Freesia hybrida Hort.) 'Dancing Flame' was developed for the cut flower in the National Institute of Horticultural Herbal Science in 2007. This hybrid was selected from a crossing between a seedling 'Vulcano' and 'Sailor', which is scarlet double flowering and purple single flowering, respectively, and 'Figaro' which is bright red color and semi-double flowering, in 2000. Morphological characteristics of the selected hybrid were investigated for 3 years from 2005 to 2007, and then it was named 'Dancing Flame'. 'Dancing Flame' had red color (RHS R44B) and single flower with yellow center color (RHS Y9A). The growth of the plant was vigorous and the average height was 93.3 cm. The average flower width was 60 mm, number of floret per stalk was 14.3, and stalk was 13.2 cm length. The average yield, 7.8 cuttings per plant, was 2.5 stems per plant more than the control cultivar. The average days to first flowering of 'Dancing Flame', 133 days, was approximately 5 days earlier than the control cultivar. And its average yield, 7.1 cormlet per plant, was also 2.5times more than the control cultivar.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1051-1054
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• 2000

We developed the micro CSF (celebrospinal fluid) shunt valve with surface and bulk micromachining technology in polymer MEMS. This micro CSF shunt valve was formed with four micro check valves to have a membrane connected to the anchor with the four bridges. The up-down movement of the membrane made the CSF on & off and the valve characteristic such as open pressure was controlled by the thickness and shape of the bridge and the membrane. The membrane, anchor and bridge layer were made of the $O_2$ RIE (reactive ion etching) patterned Parylene thin film to be about 5~10 microns in thickness on the silicon wafer. The dimension of the rectangular nozzle is 0.2＊0.2 $\textrm{mm}^2$ and the membrane 0.45 mm in diameter. The bridge width is designed variously from 0.04 mm to 0.12 mm to control the valve characteristics. To protect the membrane and bridge in the CSF flow, we developed the packaging system for the CSF micro shunt valve with the deep RIE of the silicon wafer. Using this package, we can control the gap size between the membrane and the nozzle, and protect the bridge not to be broken in the flow. The total dimension of the assembled system is 2.5＊2.5 $\textrm{mm}^2$ in square, 0.8 mm in height. We could precisely control the burst pressure and low rate of the valve varing the design parameters, and develop the whole CSF shunt system using this polymer MEMS fabricated CSF shunt valve.