• 한국가시화정보학회지
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• 제19권3호
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• pp.15-21
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• 2021

In this study, we investigated the dynamics of a droplet impacting rough hydrophobic surfaces through high-speed imaging. Micrometer-sized structures with grooves and pillars were fabricated on smooth Polydimethylsiloxane (PDMS) surfaces by laser ablation. We used Newtonian and non-Newtonian liquid droplets to study the drop impact dynamics. De-ionized water and aqueous glycerin solutions were used for the Newtonian liquid droplet. The solutions of xanthan gum in water were prepared to provide elastic property to the Newtonian droplet. We found that the orientation of the surface structures affected the maximal spreading diameter of the droplet due to the degree of slippage. During the droplet retraction, the dynamic receding contact angles were measured to be around 90° or less. It resulted in the formation of the micro-capillary bridges between the receding droplet and the surface structures. Then, the rupture of the capillary bridge led to the formation of micrometer-sized droplets on top of the surface structures. The size of the microdroplets was found to increase with increasing the impacting velocity and viscosity of the Newtonian liquid droplets. However, the size of the isolated microdroplets decreased with enhancing the elasticity of the droplets, and the size of the non-Newtonian microdroplets was not affected by the impacting velocity.

• Journal of Periodontal and Implant Science
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• 제31권4호
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• pp.737-747
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• 2001

Regeneration of Periodontium with PRP does not only improve regeneration rate and density of bone but have a possibility to estimate faster healing process for soft tissue. And also, synthetic bone and xenogenic bone graft are effective on regeneration of periodontium. The purpose of this study is to evaluate the effectiveness of synthetic bone ($Biogran^{(R)}$) and xenogenic bone ($BBP^{(R)}$) grafts with the PRP technique on regeneration of periodontium. 52 Generally healthy Pt. who had pocket depth 5mm at any of 6 surfaces of the teeth were in the study at Dept. of Perio. in Dankook Dental Hospital. Open Flap was treated for 18 infra-bony pockets as control group, $Biogran^{(R)}$ with PRP was inserted for 25 infrabony pockets as first test group, and $BBP^{(R)}$ with PRP was inserted for 22 infrabony pockets as 2nd test group. Then evaluation was made after 3 and 6 months 1. 6 months after surgery, each difference of average probing pocket depth was $2.61{\pm}0.23$ for control, $3.40{\pm}0.30$ for 1st test, and $3.45{\pm}0.37$ for 2nd test group. 2. 6 months after surgery, each difference of clinical probing attachment level was $1.39{\pm}0.12$ for control, $2.88{\pm}0,24$ for 1st, and $2.86{\pm}0,27$ for 2nd test group. 3. 6 months after surgery, each difference of Maximal probing attachment level was $1.11{\pm}0.16$ for control, $3.28{\pm}0.30$ for 1st, and $3.27{\pm}0.35$ for 2nd test group. 4. There were significant differences for clinical change of each three group which were between average probing pocket depth and clinical attachment level of 3,6 months and minimal and maximal attachment level after 6 months 5. There were significant differences for average probing pocket depth which were only at control group and 2nd test group between 1 and 6months. For clinical attachment level and minimal and maximal proving attachment level, there was a significant difference after 6month of surgery. 6. There was no significant difference between two test groups for average probing depth, clinical attachment level, and minima1 and maximal probing attachment level. As the result, PRP with bone graft is very effective for regeneration of periodontium and there is no difference between xenogenic bone and synthetic bone.

• 한국정보과학회논문지:시스템및이론
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• 제26권8호
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• pp.875-883
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• 1999

서로 다른 기하학적 모델링 시스템에 사용되는 곡선 및 곡면의 자료 교환에서, 시스템이 지원하는 그 곡선 및 곡면의 최대 차수에 제한이 있을 때, 낮은 차수로의 차수 감소가 필요하다. 본 논문에서는 근사 변환에 의한 B-spline 곡선의 차수 감소 방법을 제시한다. 기존의 Bzier 곡선의 차수감소 방법들을 적용하고, 그 방법들을 비교 분석한다. B-spline 곡선의 knot 제거 알고리즘이 자료 감소를 위해 차수 감소 과정에 적용된다.Abstract The degree reduction of B-splines is required in exchanging parametric curves and surfaces of the different geometric modeling systems because some systems limit the supported maximal degree. We propose an approximate degree reduction method of B-spline curves using the existing Bzier degree reduction methods. Knot removal algorithm is used to reduce data in the degree reduction process.

• 한국컴퓨터정보학회논문지
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• 제10권1호
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• pp.35-44
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• 2005

서로 다른 기하학적 모델링 시스템을 사용하는 곡선 및 곡면의 자료 교환에서, 시스템이 지원하는 B-spline 곡선 및 곡면의 최대 차수에 제한이 있을 때, 주어진 허용 오차 범위 내에서 낮은 차수로의 차수 감소가 필요하다 본 논문에서는 근사 변환의 한 방법인 B-spline 곡선의 차수 감소 방법을 적용한 실험적 결과를 제공한다. B-spline 곡선의 근사변환에서 기존의 $B\acute{e}zier$ 곡선의 차수감소 방법들을 차수 감소 과정에 적용하고. 그 방법들을 비교 분석한다 knot 제거 알고리즘도 자료 감소를 위하여 차수 감소과정에 적용한다

• 한국컴퓨터정보학회논문지
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• 제8권1호
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• pp.7-12
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• 2003

시스템이 지원하는 곡선 및 곡면의 최대 차수에 제한이 있을 때, 낮은 차수로의 차수 감소가 필요하다. 본 논문에서는 근사 변환의 한 방법으로써 NURBS 곡선의 차수 감소 방법을 소개한다. 이 방법은 기존 Eck의 B$\'{e}$zier 차수 감소 방법과 자료 감소를 위해 knot 제거 알고리즘이 적용된다. 제시하는 방법은 안정적일 뿐만 아니라 수학적으로도 단순하므로 이해와 구현이 용이하다.

• 대한통합의학회지
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• 제4권3호
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• pp.17-25
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• 2016

Purpose : This study attempts to examine the effect of the balance exercise on the unstable surfaces for the vital capacity in healthy adults. Methods : A total of 13 subjects was randomly divided into a breathing exercise training group (n=7) and a breathing and balance exercise training group (n=6). Changes in vital capacity and respiratory muscle activity were measured before and after the intervention. The intervention was performed three times a week for four weeks. Forced vital capacity (FVC), forced expiratory volume at one second (FEV1) and maximal voluntary ventilation (MVV) were used as measurement tools for the vital capacity test. Electromyography (EMG) was also used to examine respiratory muscle activity. Result : The breathing exercise training group showed significant improvement in terms of FVC, FEV1 and external oblique (EO), and transverse abdominis/internal oblique (TrA/IO) of MVV. The breathing and balance exercise training group showed significant improvement in terms of FVC, MVV and EO, TrA/IO of FVC and rectus abdominis (RA), EO, and TrA/IO of MVV. However, in comparing changes in vital capacity and respiratory muscle activity before and after the training, the breathing exercise training group and the breathing and balance exercise training group showed a significant difference in terms of MVV. Conclusion : This study is as a preliminary study to find out the relation between a balance exercise and a vital capacity, it is considered to require a further study with several revisions of subjects, duration and time for an intervention.

• ALGAE
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• 제24권2호
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• pp.93-104
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• 2009

Imaging-PAM fluorometry was used to assess the chlorophyll a fluorescence parameter ${\Phi}_{PSII}$ (effective quantum yield) in Frcus vesiculosus. F. disttchus. ssp. distichus and AscophyIIum nodosum. The objective was to show variadon in fluorescence yield associated with age and frond organ, and to illustrate the spatial scales at which photosynthetic parameters vary on fucoid thalli. In addition, our species represented taxa in different but related genera, species with different ecoloeies (rock pool and non rock pool species), morphologies (with and without air bladders) and longevities (several to 20 or more years). A further objective was to determine the extent to which photosynthetic parameters reflected these differences- Effective quantum yield declined substantially with age in F. vesiculosus and F. distichus ssp. distichus, whereas ${\Phi}_{PSII}$ in A. nodosum was maximal after three years. In A. nodosum ${\Phi}_{PSII}$ was still high in branch segments at least seven years old. Older branches of A. nodosum showed relatively higher and more homogeneous photosynthetic capacity relative to Fucus species. Surfaces of air bladders in A. nodosum and F. vesicu- losus had ${\Phi}_{PSII}$ that was not significantly different from the highest rates, achieved in these species. The heterogene- ity of photosynthetic efficiency is consistent with morphological and developmental differences among the species and their ecology. in particular the longevity of A. nodosum fronds.

• 한국지형학회지
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• 제17권1호
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• pp.73-84
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• 2010

본 논문은 가시권 분석에서의 지형 요소의 효율성과 활용성에 대한 내용으로써 지형 요소별로 가시권 분석 결과를 비교하여 각 지형 요소와 가시권 분석간의 관련성을 분석한 연구이다. 이를 위해 본 연구에서는 peak, pass, pit, ridge, valley를 지형 요소로 선정하고 조망 지점에서 최대 가시 면적을 확보하는 문제를 가시권 문제로 정의하였다. 또한 다양한 지형적 요인을 고려하기 위해 산악 지역에서부터 평야 지역까지를 대상으로 하였다. 분석 결과는 다음과 같다. 첫째, 해발고도와 가시 면적과의 상관 관계는 낮게 나타났다. 이는 넓은 가시권 확보를 위해 고도가 높은 지점들을 우선적으로 선정하는 방법은 효과적이지 않다는 의미이다. 둘째, 넓은 가시 범위를 보이는 상위 지점들은 해발 고도의 편차가 적다는 점이다. 이는 넓은 가시 범위를 확보하기 위해서는 어느 정도의 해발 고도 지점을 대상으로 해야 한다는 의미이다. 셋째, 가시권 상위 지점들과의 가시권 비교 결과, 모든 연구 지역에 걸쳐 다섯 유형의 지형 요소가 최대 가시권 확보 면적과 유사한 결과를 나타내었다. 이 결과는 가시권 분석에서 지형적 요인의 중요성과 지형 요소의 기여방안에 대한 논의 토대가 될 수 있음을 의미한다. 또한 본 연구의 결과는 향후 최대 가시권 분석에 있어 가시권에 영향을 주는 요인 및 변수 선정에 기여할 것으로 기대할 수 있다.

• Journal of Oral Medicine and Pain
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• 제20권1호
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• pp.185-194
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• 1995

The purpose of this study was to estimate primary diagnosis, prediction of prognosis and recognition fo treatment progress for treatment of TMD patients through measuring the various ranges of mandibular movement in normal and TMDs patients using Mandibular Kinesiograph K-6 Diagnostic system. In normal groups, 20 adults were selected, who have normal or class I molar relationship, and have no symptoms on TMJ and masticatory muscles, and have restorations less than 3 surfaces on each tooth, and have no other prosthetic restoration. In Patients group, we selected 31 outpatients who were confirmed to TMDs with clinical examination and radiographic findings. The obtained results were as follows : 1. In maximal opening, patient group was showed the limitation of vertical movement range (P<0.01) and lager lateral deviation than in normal group (P<0.05). And actual dimensional displacement of opening was calculated larger in normal group (P<0.05). 2. In protrusive movement, patients group was showed the limitation of anteroposterior movement range (P<0.001) and larger deviation than in normal group (P<0.01). And actual 3 dimensional displacement of protrusion was calculated larger in normal group (P<0.001). 3. In lateral maximum excursion, compared with normal group patient group was no significant differences to affected side, but was showed the limitation of lateral movement to unaffected side (P<0.001). 4. There was no significant difference in movement velocity of opening and closing in both groups. 5. Mandibular movement from physiologic rest position to centric occlusion was moved more anteroposteriorly in patient group. 6. Mandibular movement from centric relation to centric occlusion was no significant difference in both groups.

• Journal of Oral Medicine and Pain
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• 제20권1호
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• pp.195-204
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• 1995

The purpose of this study was to evaluate effect of head posture change on initial occlusal contacts through measuring the distances between initial occlusal contacts and maximum intercuspal position at different head posture. Two special devices were designed and constructed. Mandibular movement replicator was used to assess reliability of the K6 diagnostic system(MKG; Myo-tronic Inc, Seatle, USA) and head posture calibrator was used to maintain the constant head posture during experiment. We measured difference of distance between initial occlusal contact and maximum intercuspal position with MKG in upright, supine, 45 degrees extension, 30 degrees flexion, 30 degrees right and left bending postion of the head. The Frankfurt horizontal plane was used as a reference plane. 21 adults aged from 23 to 25 were selected, who have normal or class I molar relationship, and have no symptoms on TMJ and masticatory muscles, and have restorations less than 3 surfaces on each tooth, and have no other prosthetic restoration. The obtained results were as follows : The mean absolute distances between initial occlusal contact and maximum intercuspal postion were 0.39(0.18mm in the upright position, 0.65(0.37mm in the supine position, 0.59(0.33mm in the 45 degree extension, 0.70(0.53mm in the 30 degrees flexion, 1.12(1.10mm in the 30 degrees right bending and 1.94(0.67mm in the 30 degrees left bending of the head. The positions of the initial occlusal contacts have a tendency to locate anterior, left and inferior to maximal intercuspal position in upright position, posterior and inferior in supine position and 45 degrees extension, anterior and inferior in 30 degrees flexion, right and inferior in 30 degrees right bending, and left and inferior in 30 degrees left bending of the head. There were significant differences among the initial occlusal contacts in each head postures(P<0.0001). Therefore, we need to check initial occlusal contacts in the altered head posture during occlusal analysis and adjustment of occlusal appliance and dental occlusion for diagnosis and treatment of temporomandibular disorder.