• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.27-32
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• 2006

In this paper, the contact stress and friction force between multi-balls and rolling friction contact surfaces of two cylinders have been presented using a finite element analysis. The multi-balls for a rolling friction motion may be contacted with a reciprocating mechanism of a parallel cylinder and a misaligned cylinder in a LPG filling unit. The FEM computed results indicate that SiC ceramic and SUS 304 balls show a high contact stress and friction force on the contact spot of rolling balls. But the PEEK balls show a low contact stress and friction loss due to a high flexibility of a PEEK polymer. In this study, we may recommend SiC and SUS 304 balls for high compressive loadings between a multi-ball and a cylinder contact mechanisms and PEEK balls for a low compressive force. And the misalignment between two cylinders should be restricted for a low contact stress and friction loss, especially.

• Proceedings of the KSLP Conference
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• 2003.11a
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• pp.167-169
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• 2003

성대의 마비는 그 원인과 정도에 따라 애성, 연하장애, 호흡장애 등 다양한 기능 결손을 초래하게 되므로, 마비된 성대에 의한 불편을 외과적으로 처치하기 이전에 반드시 마비의 원인에 대한 이해와, 환자의 불편에 대한 정확한 이해가 선행되어야만 적합한 술식을 선택할 수 있다. 예를 들어 두개저수술의 합병증으로 갑자기 발생된 성대마비와 갑상선암에 의하여 서서히 진행된 성대마비의 경우 그 예후나 경과가 전혀 다른 질환이라 할 수 있기 때문이다. (중략)

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.206-211
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• 1993

We carried out the second harmonic generation of low power CW laser diode with maximum power of 30 mW in $LilO_3$ crystals. We used a ring enhancement cavity to increase the second harmonic conversion efficiency. The ring enhancement cavity was Composed of two flat mirrors and two concave mirrors. The focal length of concave mirrors was 25 mm, and 5 mm long and 10 mm long $LilO_3$ crystals were used. We measured the second harmonic power according to the pumping power and compared with theoretical value. We obtained 397 nm second harmonic power of about $6.6{\mu}W$ in 10 mm long $LilO_3$ crystal with the fundumental 794 nm pumping power of 28 mW.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2479-2488
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• 1994

In this paper, a new dynamic excitation modeling scheme is proposed. Based upon the proposed excitation modeling scheme, two variable bit rate homomorphic vocoders are designed, whose average bit rates are 3.8 Kbps and 4.4 Kbps. The performance of the proposed excitation modeling scheme is then evaluated through the subjective listening tests. In the tests, the performances of two speech coders designed in this paper ate compared with the one of 4.8 Kbps homomorphic vocoder designed by Chung and Schafer, in which conventional static excitation modeling scheme applied. The subjective listening tests show that proposed dynamic excitation modeling scheme improves synthesized speech quality while lowering the average bit rate of speech coders.

• Journal of Korean Neurosurgical Society
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• v.29 no.3
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• pp.402-406
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• 2000

The term 'craniovertebral junction' refers to the occipital bone that surrounds the foramen magnum and the atlas and the axis vertebrae. A wide variety of congenital, developmental, and acquired anomalies exist at the craniovertebral junction. The authors present a rare case of the congenital anomaly of the craniovertebral junction consisting of atlantal hypoplasia, atlantal assimilation, and basilar invagination in a 58-year-old male. An occiput-C2 arthrodesis was performed. The clinical and imaging features are described, and the embryology and etiology of this anomaly are discussed.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.763-774
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• 1998

The purpose of this study was to evaluate the morphology of mandibular symphysis and location of lower incisor under the influence of the craniofacial skeleton in skeletal Class III malocclusion. The sample consisted of 132 adults who have severe Class III malocclusion(prognathism group, 33 males and 33 females), and who have normal occlusion(normal group, 33 males and 33 females). They had not received any orthodontic treatment or orthognathic surgery. The lateral cephalograms were evaluated. The results were as follows : 1. Prognathism group were larger than normal group in comparison of facial skeleton (p<0.05) with the exception of ${\angle}FH-Pal$, ${\angle}SNA$. 2. In the morphology of symphysis, measurements of anteroposterior width(LaABBW, LiABBW, SW) of prognathism group were significantly less than that of normal group(p<0.001). 3. In the correlative analysis between the craniofacial skeleton and symphysis measurements of prognathism group, vertical measurements in relation with cranial base and mandibular plane showed reverse correlationship with anteroposterior width of symphysis(LiACBW, LaACBW, LiABBW, SW)(p<0.05). But, there was not distinct difference between horizontal skeletal measurements and symphysis measurements(p>0.05). 4. The probability by regression test between vertical measurements(${\angle}SN-Mn,\;{\angle}FMA,\;{\angle}Pal-Mn,\;{\angle}LFH$) and symphysis measurements(LiACBW, LiABBW, SW, ${\angle}LISA$) were very high(p<0.001).

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.95-105
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• 2001

The present study was designed to compare morphological and structural relationships between basicranial measurements such as MCF angulation (Ar-SE-ptm), saddle angle (N-S-Ba, N-S-Ar) and facial structures including types of malocclusion. Twenty six children with Class III whose longitudinal headfilms were available from 7 to 12-year-old, and also 26 cross-sectional headfilms at each ages of 8, 9, 10 and 11 with Class I were selected for the investigation. Cephalometric measurements such as Ar-SE-ptm, N-S-Ba, N-S-Ar, N-SE-Ar, SNA, SNB, N-S/PM vert, CP/PM vert, $\underline{1}/FH$ plane, and $N-perp/\underline{1}$ were measured. Morphologic relationships and pattern of changes in facial structures in relation to the changes of MCF and saddle angle in both malocclusion types were analysed statistically employing ANOVA, t-test and Pearson correlation. Results suggest that the MCF rather than the saddle angle in children with Class I and III is more closely related with various facial structures and with their changes. It may be, therefore, suggested that the MCF be one of the biologically meaningful measurements in determining structural relationships between cranial base and facial complex including types of malocclusion. In addition, the MCF and its correlated facial structures in children with Class III, interestingly, showed somewhat marked changes between the ages of 9 and 11.

• 대한미세수술학회:학술대회논문집
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• 1993.10a
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• pp.103.2-104
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• 1993

• The Korean Journal of Pain
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• v.22 no.1
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• pp.88-91
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• 2009

Skull base osteomyelitis is a rare but life-threatening complication of inflammation of the ear. The authors present a case of skull base osteomyelitis of unknown etiology in a non-diabetic patient who presented with unilateral posterior neck and occipital headache mimicking cervicogenic headache.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.299-307
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• 2011

This study was performed to report the effectiveness of upper cervical chuna and release of cranial base on patients with dry eye syndrome. The patients diagnosed as dry eye syndrome and treated with upper cervical chuna and release of cranial base. Outcomes were measured by ocular surface disease index(OSDI). After treatments, discomfort and ocular surface disease index decreased. These results suggest that upper cervical chuna and release of cranial base were effective on patients with dry eye syndrome.