• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.213-220
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• 2023

Mixed-matrix membranes (MMMs), which are composed of a polymer matrix filled with high-performance fillers as a dispersed phase, have been intensively studied for gas separations for the past 30 years. It has been demonstrated that MMMs exhibit superior gas separation performance compared to polymer membranes and are more scalable than polycrystalline membranes. Despite their potential, the commercialization of MMMs has yet to be reported due to several challenging issues. One of the major challenges of MMMs is the non-ideal interface between the continuous polymer phase and dispersed phase, which can result in defect formation (i.e., interfacial voids, etc.). With respect, many MMM studies have focused on addressing the issues through scientific approaches. The engineering approaches for facile and effective large-scale fabrication of MMMs, however, have been relatively underestimated. In this review paper, a novel strategy for fabricating MMMs in a facile and scalable manner using in situ metal-organic framework (MOF) formation is introduced. This new MMM fabrication methodology can effectively address the issues facing current MMMs, likely facilitating the commercialization of MMMs.

• Journal of the Korea Computer Graphics Society
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• v.30 no.3
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• pp.189-198
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• 2024

Research combining deep learning-based models and physical simulations is making important advances in the medical field. This extracts the necessary information from medical image data and enables fast and accurate prediction of deformation of the skeleton and soft tissue based on physical laws. This study proposes a system that integrates Neural Radiance Fields (NeRF), Position-Based Dynamics (PBD), and Parallel Resampling to generate 3D volume data, and deform and visualize them in real-time. NeRF uses 2D images and camera coordinates to produce high-resolution 3D volume data, while PBD enables real-time deformation and interaction through physics-based simulation. Parallel Resampling improves rendering efficiency by dividing the volume into tetrahedral meshes and utilizing GPU parallel processing. This system renders the deformed volume data using ray casting, leveraging GPU parallel processing for fast real-time visualization. Experimental results show that this system can generate and deform 3D data without expensive equipment, demonstrating potential applications in engineering, education, and medicine.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.733-741
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• 1997

As a result of surgical orthodontic treatment of mandibular prognathism, changes take place in the skeletal and soft orofacial components. Although some investigators had stated that permanent reduction of airway space was observed after mandibular setback surgery, it was not clear that this permanent reduction was sustained during long-term follow-up. The purpose of this study was to assess the changes in oropharyngeal airway space and soft tissue orofacial component following the mandibular setback surgery and during the follow-up period. The correlation between the changes of the oropharyngeal airway space and the changes of other soft tissue orofacial component was also assessed. The findings of this study were as follows ; 1. The oropharyngeal airway space area decreased following mandibular setback surgery for mandibular prognathism and continued to decrease during the follow-up period(p<0.05). 2. The pharyngeal depth at Xi point level and the 2nd cervical vertebra point level decreased after the surgery and remained during the follow-up period(p<0.05). The decrease of these pharyngeal depth was correlated with the decrease of oropharyngeal airway space area(p<0.01). 3. The decrease of pharyngeal depth at the 3rd and 4th cervical vertebra point level was not significant after the surgery and during the follow up period. 4. The hyoid bone moved downward after the surgery(p<0.05), but returned to its original position during the follow-up period. 5. The length & height of tongue and the Position of epiglottis base did not change significantly(p>0.05). 6. The soft palate was displaced posteriorly after the surgery and remained to its changed position during the follow-up period(p<0.05) due to posterior displacement of tongue. The changes of soft palate were significantly correlated with the decrease of oropharyngeal airway space area(p<0.01). 7. The narrowing of oropharyngeal airway space was due to the posterior displacement of tongue above the level of epiglottis tip. The posterior displacement of tongue following mandibular setback osteotomy remained during the follow-up period.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.216-226
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• 2005

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs (Quick Ceph Image $Pro^{TM}$ (ver 3.0) and $V-Ceph^{TM}$(ver 3.5)) for mandibular set-back surgery. The presurgical and postsurgical lateral cephalograms of 40 patients (20 males and 20 females) were traced on the same acetate paper with the reference taken as the cranial base outline. The presurgical skeletal outlines were digitized onto each computer program and the mandible was moved to mimic the expected surgical procedure with reverence to the mandibular anterior border and lower incisor position of the actual postsurgical skeletal outline. The soft tissue profile was generated and the amount and direction of skeletal movement was calculated with each software. The predicted soft tissue profile was compared to the actual postsurgical soft tissue profile. There were differences between the actual and the predicted surgical soft tissue profile charges in the magnitude and direction, especially the upper lip. lower lip and the soft tissue chin (P<0.05). Quick Ceph had more horizontal measurement errors and thickness errors for the upper lip and lower lip, but V-Ceph had more vertical measurement errors of the lower lip (P<0.05). There was a positive correlation between the prediction errors and the amount of mandibular movements in the vertical position of Sn, the horizontal position of Ls and the upper lip thickness for V-Ceph, and there was a negative correlation in the horizontal position and the thickness of the lower lip for Quick Ceph (P<0.05). However all of the Prediction errors of both imaging softwares were ranged within 3mm, and this was considered to be allowable clinically.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.491-507
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• 2000

The purpose of this study was to investigate if there were a significant differences in mandibular position between cephalometric measurements from a centric occlusion tracing compared to those of a acquired centric relation by stabilization splint on malocclusion patient with TMD. 60 malocclusion patients, who had TMD and CO-CR discrepancy beyond normal range, were selected and subdivided into Class I, II, III by Angle's classification and also subdivided into clockwise, straight downward, and counterclockwise group by Jarabak's posterior facial height/anterior facial height ratio. Lateral cephaolmetric radiographs with the mandible in centric occlusion were taken and measured, and for each Patient the stabilization splint with mutually protected occlusal scheme was applied for minimum 3months. After each patient's CO-CR discrepancy was in normal range, lateral cephalometric radiographs were retaken and measured. The comparison of the difference between CO-CR cephalometric measurements in all sample, Class I, II, III groups, and Clockwise, Straight downward, Counterclockwise groups were studied. The finding of this study can be summarized as follows: 1 In all sample, the value of cephalometric measurements was significantly different between CO-CR. The mandible rotated to down and posterior position and the vertical change was greater than the horizontal change (overjet-1.3mm increase, overbite-1.9mm decrease). 2. In Class II malocclusion group, most of the mean difference value between CO-CR is higher than that of the other groups and more measurements was statically significant. 3. In clockwise and counterclockwise group, some of the mean difference value is higher than that of straight downward group and more measurements was statically significant. 4. There ware no measurements that explain centric relation measurements from the type of malocclusion, facial pattern and centric occlusion measurements. Henceforth, it is strongly recommended that stabilization splint therapy for orthodontic treatment on TMD patient should be excuted upon overall facial types prior to orthodontic diagnosis and treatment planning.

• Korean Journal of Heritage: History & Science
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• v.47 no.4
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• pp.22-47
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• 2014

This study was to understand the basic principles of the East Asian wooden structure system research and analysis. The Korea and China ancient architecture internal structure research that the combination of girders and crossbeams position. The ancient wooden structures of eastern Asian countries, Korea and China are not much different from each other in the principles of the wooden architecture structure, combining pillars, purlins and crossbeams. However, it seems that age-division, local-division, national-division differs in detail techniques. China ancient wooden structures combination of purlin and crossbeam, and So-seul Timber(Chinese name: Chashou叉手, Tuojiao 托脚) seems to show differences according to the age of the fulcrum position, detailed approach is also different according to various historical dynasty. Before in the 15th century, Purlin and Crossbeam are coupled to each other, but since the 15th century, seems to have developed a technique combined with each other Girder and Crossbeam and to prevent buckling of the Crossbeam cross-sectional area increased dramatically. For Tuojiao in China Tang-Wudai dynasty(A.D. 618~979), can see that saw the top position Girder and Tuojiao no direct coupling, can be seen as maintaining the safety of the material than the material of the inner wooden structures prevent buckling of the purlin. Korea ancient wooden structures of Goryeo dynasty(A.D. 918~1391), So-seul Timber(Chinese name Tuojiao) why do not to use the fashion? To use Purlin Lower backing material techniques to prevent buckling is a popular trend to stable can be thought of as a preferred way to maintain. I think that with universality beyond the local-division, national-division and the two countries since the 15th century of Korea and China ancient wooden structures detailed mechanism for the purlin buckling. In middle-late Chosen dynasty, The effect of Deotgeolyi- techniques and fleeting beams reduce the purlin buckling that reduces the load transmitted from purlin and crossbeam of how to reduce the load on the roof portion of the architecture fleeting beams used, which of craftsmanship of the Chosen Dynasty building can be referred to as another technique for preventing buckling purlin. This Korea and China ancient architecture purlin beam structure and material So-seul Timber study. Seems to be able to provide a basic research study to restore and designed the old wooden architectures.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.401-413
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• 1996

Facial vertical dyscrepancies is decided on the relationship between the anterior vertical facial height and posterior vertical facial height. Thus this study was conducted to determine the factors that affect the FHI, and classify the Class II div.1, malocclusion, which success is dependent on the vertical control according to the FHI, which is the ratio of antero-inferior facial height, posterio-inferior facial height ratio, and to use this as a guideline for treatment. Angle between palatal plane and Mandibular plane were in the order of RH, ID. Thus showing that interrelated angle was more inportant than the independent angle of both, palatal plane and Mandibular plane. The tendency of Cl II div.1. Malocclusion according to FHI, showed the Low group to have Mx. protrusion, prominent development of Mn. ramus, and the Mn. body length and ant. post. position was normal. The Normo group showed slight protrusion of the Maxilla,. The development of the ramus was less than normal and the Mn. was in a slight retruded position. The High group showed the Mx. in a normal position, the development of the Mn. ramus and body was the lowest, and the Mn. was in a posterior position. In observation of the factors affecting the FHI between each groups of Cl II div.l, malocclusion; In the Low group the MP- PP angle was very small, the ID was smililar to the normal group, but the RH was very large thus the FHI was increased. In the Normo group, the PP-MP angle was normal, ID was slightly smaller than the normal group and the RH was slightly smaller than the normal group, thus maintaining a normal FHI ratio. In the High group the PP-MP angle was very large, the ID was similar to the normal group, but the RH was smaller than the normal group thus the FHI was small.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.239-249
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• 1999

In orthognathic surgery to obtain proper functional and esthetic form after skeletal discrepancy treatment, precise diagnosis and treatment plan are essential. Especially in two jaw surgeries that have serious upper and lower jaw problems, maxilla and mandible are arranged in three dimensions. Based on the maxillary rearrangement, mandibular sagittal and transverse positions are determined, and thus new occlusal plane is established. The object of this study is to evaluate the stability of the indiviual ideal occlusal plane based on the architectural and structural craniofacial analysis of Delaires. The subjects of this study were 48 patients who underwent two jaw surgeries, and they were equally divided into two groups, A and B. A group was operated with ideal occlusal plane and B group was not. Two groups were compared at the preoperative, immediate postoperative (average 4.3days), and long-term postoperative (average 1.3years) lateral cephalometric radiographs. The following results were obtained: 1. ANS was lower than that of PNS for both A and B after the surgery. That is, maxilla and mandible are rotated in posterior and superior direction. 2. Significances were found between $T_2$ and $T_3$ for both A and B are HRP-Me at vortical measurements, articular angle(p<0.01), gonial angle(p<0.01), and Mn. plane angle(p<0.05) at angular measurement. Mn. plane angle is increased at HRP-Me is decreased for both A and B. 3. There is no significance in skeletal stability aster the surgery between group A and B. 4. Horizontal movements of B and Pog by surgery have statistically significant inverse correlations with horizontal relapse of B and Pog, and vertical relapse of PNS, as well as Mn. Plane angle, and gonial angle after the surgery.

• The korean journal of orthodontics
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• v.33 no.5 s.100
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• pp.339-350
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• 2003

The purpose of this study was to investigate the micro-implant height and anterior hook height to prevent maxillary six anterior teeth from lingual tipping and extruding during space closure. We manufactured maxillary dental arch form, bracket and wire, using the computer aided three-dimensional finite element method. Bracket was $.022'{\times}.028'$ slot size and attached to tooth surface. Wire was $.019'{\times}.025'$ stainless steel and $.032'{\times}.032'$ stainless steel hook was attached to wire between lateral incisor and canine. Length of hook was 8mm and force application points were marked at intervals of In. Four micro-implants were implanted on alveolar bone between second premolar and first molar. The heights of them were 4, 6, 8, 10mm starting from wire. We analyzed initial displacement of teeth by various force application point applying force of 150gm to each micro-implant and anterior hook. The conclusions of 4his study are as the following : 1. When the micro-implant height was 4m and the anterior hook height was 5mm and below, anterior teeth were tipped lingually. When the anterior hook height was 6mm and above, anterior teeth were tipped labially. 2. When the micro-implant height was 6mm and the anterior hook height was 6mm and below, the anterior teeth were tipped lingually. When the anterior hook height was 6m and above, the anterior teeth were tipped labially. But lingual tipping of anterior teeth decreased and labial tipping Increased when the micro-implant height was 6mm, compared with 4mm micro-implant height. 3. When the micro-implant height was 8mm and the anterior hook height was 2mm, the anterior teeth were tipped lingually. When the anterior hook height was 3mm and above, labial tipping movement of the anterior teeth increased proportionally. 4. When the micro-implant height was 10mm and the anterior hook height was 2mm and above, labial tipping of the anterior teeth increased proportionally. 5. As the anterior hook height increased, aterior teeth were tipped more labially. But extrusion occurred on canine and premolar area because of the increase of wire distortion. 6. Movement of the posterior teeth was tipped distally during maxillary six anterior teeth retraction using micro-im plant because of the friction between bracket and were Based on the results of this study, we could predict the pattern of the tooth movement according to position of micro-implant and height of anterior hook. It seems that we can find the force application point for proper tooth movement in consideration of inclination of anterior anterior teeth, periodontal condition, overjet and overbite

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.196-202
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• 1999

Purpose : When the mature kidney fails to reach its norml location in the renal fossa, the condition is known as ectopic kidney. Presenting symtoms can be various and it generally depend on the associated anomaly. Beside urologic anomalies such as hydronephrosis and vesicoureteral reflux, various anomalous vascular net work, skeletal anomaly or genital anomaly can be observed in this condition. Methods : Sixteen children with ectopic kidney was studied retrospectively to analyse initial presentation, accompanied anomaly and prognosis. Results : 56% of the children were accompanied with other urologic anomalies such as true incontinence and vesicoureteral reflux that required surgical treatment. 31% of children were either diagnosed incidentally during evaluation of other non-urologic disease or during follow-up evaluation of abnormal antenatal renal sonogram. Conclusion : Ectopic kidney can be often misdiagnosed as tumorous condition or as a surgical condition depend on the abnormal location of the kidney. Careful evaluation using abdominal sonogram, DMSA, VCUG and abdominal CT scan should be performed in order to search for associated anomalous condition and for proper management.