• The Journal of the Acoustical Society of Korea
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• v.34 no.5
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• pp.351-359
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• 2015

Typical underwater acoustic transducers detect only the magnitude of an acoustic pressure and they have the limitation of not being able to recognize the direction of the sound signal. Hence, the authors of this paper proposed a new vector sensor structure based on Tonpilz transducers that could detect both the magnitude and the direction of a sound pressure. In the proposed structure, the piezoceramic ring was divided into four segments, and proper combination of the output voltages of the segments in response to the external sound pressure could provide the information on the orientation of the sound source. In this paper, a Tonpilz transducer has been fabricated to have the proposed structure and its characteristics has been measured to confirm the validity of the proposed structure.

• Journal of the Korean Wood Science and Technology
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• v.15 no.3
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• pp.1-13
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• 1987

This study was carried out to investigate the variations of dimension and exterior shape of vessel elements, morphology of spiral thickening and ray-vessel pit in korean diffuse-porous woods (56 species, 18 families), The tangential pore diameter and vessel element length was increased, whereas the pore number per unit area($1mm^2$) was decreased from pith outwards. The tangential pore diameter was decreased but the length of vessel element was not changed from earlywood to latewood within an annual ring. However, the dimensional variations of vessel element was not able to be recognized among relative positions in peripheral variation. The exterior shape of vessel element could be classified into four types; Type 1 is without tail, Type 2 with ligulate tail, Type 3 with broad taper tail and Type 4 with the very short length between perforations. The distribution frequency of Type 2 and 3 was relatively high in comparision with the others. According to the prominence, distribution position and branched shape, the spiral thickenings could be divided into five types. The spiral thickenings occurred 52% in the species observed. Thus it was doubtful to consider the simple presence of spiral thickening as diagnostic index in diffuse-porous woods. The morphology of ray-vessel pit could be grouped as reticulate, scalariform, oval, linear and coalescent type. Most of species examined showed oval and linear type.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.169-173
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• 2010

Correlations between cumulus cells and germinal vesicle (GV) chromatin configuration were examined in porcine oocytes. Cumulus-oocyte complexes (COCs) were collected from 2~6 mm follicles and divided into three categories according to cumulus cell morphology. "A" group was compacted COCs with more than three cumulus cell layers. "B" group was COCs with less cumulus cell layers than "A" group. "C" group was COCs with one or less layer of cumulus cells. Cumulus cells were removed 0.1% hyaluronidase, and denuded oocytes were stained with Hoechst 33342. GV chromatin configuration was classified into GV-Con and GV-Dis. GV-Con meant that a nucleus was surrounded by condensed chromatin in a ring. GV-Dis meant that filamentous chromatin clumps were distributed in nucleus. The proportion (80.2%) of GV-Con in "A" group was significantly higher than "B" (62.0%) or "C" (44.9%). The proportion (55.1%) of GV-Dis in "C" group was significantly higher than "A" (19.8%) or "B" (38.0%). The meiotic competence of COCs was examined after 44 h culture. The proportion (90.0%) of oocytes reaching to metaphase II (M-II) in "A" group was significantly higher than "B" (76.5%) or "C" (45.5%). In conclusion, oocytes with good quality cumulus cell layers are synchronized early GV stage, and early GV stage is important for meiotic competence in pigs.

• Korean Journal of Pharmacognosy
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• v.2 no.4
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• pp.163-172
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• 1971

This paper attempts to observe the histological structure of Korean Arisaema ringens $S_{CHOTT}{'s}$ rhizome, to identify it's constituent and to investigate the pharmacological action with it's alcohol extract. The results are : 1) The inner structure of rhizome on the transverse section is divided into external and internal tissues by the ring of intercellular secretary sac. Raphides of calcium oxalate contained in mucilage cell, collateral vascular bundle, are extremely similar to those contained in Pinellia ternata. 2) The organs of the pistillate Arisaema ringens are larger and more plentiful than those of the staminate Arisaema ringens. The sexual identification is easy in the flowering season. 3) The alkaloid is identified by Meyer reagent as white p.p.t. at pH 2 of sulfuric acid. 4) The saponin is indentified remarkably by means of foaming reaction, Lieberman-Burchard reaction and hemolytic reaction. 5) The effect of alcohol extract on the relaxation of the isolated intestine of the rabbit is remarkably shown at the concentration of $10^{-3}g/ml$. 6) The effect of alcohol extract on the isolated ractus muscle of the frog increases the constructive action of acetylcholine at the concentration of $10^{-3}g/ml$. 7) The effect of alcohol extract on the isolated heart movement of the frog is decreased remarkably at the concentration of $10^{-3}g/ml$. 8) The effect of alcohol extract on the blood pressure of the rabbit is decreased by an interavenous injection of $10^{-3}g/kg$.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.5
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• pp.253-259
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• 2005

Magnetic encoder with relatively low pulse per rotation is generally used for detecting speed of the high-speed rotating machine. It is due to the fact of the mechanical problems of vibration and bearing stiffness and also the limit of maximum output pulse of the mounted encoder. The magnetic encoder is divided into two types, that is, toothed gear-wheel method and magnetic wheel method according to the shape of the rotation disk. In case of detecting speed by the tooth gear-wheel, the encoder itself can be acted as the additional inertia where the number of tooth determining the output pulse and the width of the wheel detecting the change of the magnetic flux density are relatively enough large considering the volume of the rotating machine. While the magnetic wheel method has the limit of the magnetizing number of the ring magnet, there is relatively few, if nv, the influence of inertia on the machine. In this paper, it is proposed a simple magnetic wheel encoder suited for the high speed rotating machine and the method of signal processing and the output characteristics are examined through the V/F operation of max 48,000(rpm) and 2.4(KW) spindle motor.

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.59-66
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• 1986

A prototype ultrasound sector B-scanner has been developed where the front-end hardware refers to all the necessary circuits for transmitting the ultrasound pulses into the human body and receiving the reflected echo signals from it. The front-end hardware can generally be divided into three parts, i.e., a pulse generator for insonification, a receiver which is responsible for processing of low-level analog signals, and a steering controller for driving the mechanical sector probe whose functions and design concepts are described in this paper. The front-end hardware is implemented which incorporates the following features: improvement of the axial resolution using a circuit which reduces the ring-down time, flexibility of generating time-gain compensation curve, and adoption of a one-chip microcomputer for generating the rate pulses based on the sensor output waveforms.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.5
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• pp.684-687
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• 2004

A study was conducted to determine the effect of live weight of pheasants on egg production and egg quality characteristics. A total of 48 ring-necked pheasants were divided into control, heavy, middle and light BW groups. Live weights of the control were 1,187 g, 1,352.92 g for heavy group, 1,247.92 g for middle group and 1,003.33 g for light group. Egg production of groups were found as 47.32, 42.82, 45.79 and 46.51% respectively, in 10 weeks of period. There were no statistical differences on egg production among the groups. The effect of live weight on egg weight, shape index, specific gravity, shell weight, shell thickness, Haugh Unit, yolk weight and albumen weight were found statistically significant (p<0.05). The effect of live weight on albumen index, membrane weight and membrane thickness were found not important (p>0.05). On the other hand, other important factors to be effective on the egg quality of pheasants should be investigated. As a result of this study, live weight of pheasant hens is not an important factor to obtain high egg production in pheasants. But, body conformation of breeding materials should be in good conditions.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.2
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• pp.163-173
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• 2013

PURPOSE: This study determined the effect of balance control therapy in the brain activation. METHODS: Twenty-two college students who showed decrease of muscle strength in O-ring test were as participants in this study. And the subjects were randomly divided into experimental group (n=13) and control group (n=9). Measurement device is portable EEG (Nihonkhoden, Japan). Examinations used twenty electrodes attached to the head to capture electrical brain signals during 5 minutes with brain activated states such as the awaked state and the data were compared between the two groups. RESULTS: After treatment by balance control therapy, P3 (p<.025) and P4 areas (p<.025) showed a significantly lower ST index in the experimental group than the control group, The variation of ST index in P4 area (p<.025) was decreased in the experimental group but was increased in the control group. CONCLUSION: These results showed that the balance control therapy was helpful to change the brain activation such as the stress (ST) index at the sensory area in the college students.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2163-2172
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• 2008

The noise to be considered as the most important in railway systems is the noise generated from the wheel/rail interaction. Such noise can be divided into three categories; that is, the rolling noise, the squeal noise and the wheel howling noise. Especially in metro systems, this type of noise has been considered seriously in recent years, and the diversified studies on the mechanism and solutions of such noise are in progress by many railways and researching bodies. In this study, a specially designed wheel absorber is installed in the wheel, and FEM analysis and laboratory tests are executed for the two cases, i.e. with wheel absorber and without wheel absorber, to check the effect of the wheel absorber in noise reduction. For the FEM analysis, the frequency response functions for respective cases are compared. And, for the laboratory test, following four cases are tested and compared; that is, i) with wheel only, ii) installation of ring damper only, iii) installation of damping material and cover, iv) installation of complete absorber system.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.281-283
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• 2005

A 3-month-old male, Cocker Spaniel with persistent regurgitation immediately after weaning and stunted growth was referred. Radiographic findings on the lateral view include ventral deviation of the thoracic trachea caused by draping of the dilated esophagus and a distinct interface of the dorsal wall of the esophagus silhouetting with the cranial thoracic hypaxial muscles. On the ventrodorsal view, the cranial mediastinum was widened with soft tissue opacity. The trachea was deviated to the right. In an esophagogram, the segmental dilation of the esophagus with constriction of the lumen just cranial to the heart base was identified. In a fluoroscopic examination, the contrast medium was massively accumulated in the cranial portion of the constricted esophagus. At surgery, it was confirmed that the esophageal tract was constricted at the cranial to the base of the heart by aberrant right subclavian artery. It was ligated and divided surgically. Current state of the referred is maintained normal condition from the surgical repair.