• Journal of Biosystems Engineering
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• 제29권2호
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• pp.167-174
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• 2004

Density is a physical property which contains information relating to the internal quality of fruits and vegetables, and can be used as an index for nondestructive quality evaluation. Density sorting has been employed by farmers for some agricultural products since ancient times. In this study, an automatic density measuring system based on the platform scale or water displacement method was developed for density sorting of watermelon. It consisted of water tan, load cell, net tray, electric motor, limit switch, control system and its program. The resolution of density was 0.001 g/㎤. In order to calibrate and evaluate the accuracy, the density was measured using a balloon kept in cold water. It showed 1.002 g/㎤ which almost correspond to real density of water. Test results with 6 watermelons and 3 replications showed that the standard deviations of the dens were 0.001∼0.004 g/㎤. The relationship between density and internal quality of watermelon was investigated using the system. The densities of hollow watermelons were less than 0.950 g/㎤, it was apparent that the density of the watermelon was related to the degree of hollowness. But the soluble solid contents and internal defects could not be estimated from the density.

• Archives of Plastic Surgery
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• 제43권2호
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• pp.204-209
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• 2016

Temporal hollowing occurs to varying degrees after pterional craniotomy. The most common cause of temporal hollowing is a bony defect of the pterional and temporal regions due to the resection of the sphenoid ridge and temporal squama for adequate exposure without overhang. The augmentation of such bony defects is important in preventing craniofacial deformities and postoperative hollowness. Temporal cranioplasty has been performed using a range of materials, such as acrylics, porous polyethylene, bone cement, titanium, muscle flaps, and prosthetic dermis. These methods are limited by the risk of damage to adjacent tissue and infection, a prolonged preparation phase, the possibility of reabsorption, and cost inefficiency. We have developed a method of temporal augmentation using a calvarial onlay graft as a single-stage neurosurgical reconstructive operation in patients requiring craniotomy. In this report, we describe the surgical details and review our institutional outcomes. The patients were divided into pterional craniotomy and onlay graft groups. Clinical temporal hollowing was assessed using a visual analog scale (VAS). Temporal soft tissue thickness was measured on preoperative and postoperative computed tomography (CT) studies. Both the VAS and CT-based assessments were compared between the groups. Our review indicated that the use of an onlay graft was associated with a lower VAS score and left-right discrepancy in the temporal contour than were observed in patients undergoing pterional craniotomy without an onlay graft.

• Archives of Plastic Surgery
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• 제32권3호
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• pp.304-310
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• 2005

Bulging of the lower eyelid & tear trough groove is regarded as a sign of aging. In the past, the surgical excision of the fat pad has been the mainstray of the management of lower palpebral bag in cosmetic blepharoplasty, Recently, fat pad sliding method has been introduced to make more attractive lower eyelids. We used the fat pad for covering the hollowness of the lower eye lid. And we use redundant fat pad for filling & augmentation of the lower eye lid by reflexion. Redraping of the orbicularis arc, with its accompanying midfacial fat repositioning, anatomically restores the cheek and lower lid to make more youthful contour. By redraping and fixing the orbicularis arc on the medial surface of the orbital rim, it becomes a more attractive midface and may prevent of ectropion. From August, 2002 to July, 2004 in correction of lower palpebral bulge & tear trough groove, these two technique were performed in 42 consecutive individuals (84 lower eyelid) for two-year period. Follow up ranged from 3 to 15 months. (an average of 9 months) Palpebral bulge & tear trough groove were corrected and obtained a youthful midface. Complication was rare. The advantages of these techniques are that: prevent in of secondary palpebral bulge and irregularity of lower eyelid by using of reflexed fat fad; prevent in of ectropion. Thus an attractive midface is obtained by redraping of orbicularis arc.

• Archives of Plastic Surgery
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• 제33권3호
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• pp.335-340
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• 2006

Lower palpebral bags and tear trough grooves are the common signs of aging. Weakness of the orbital septum, atrophy of the orbicularis oculi muscle, slackness and laxity of the lower lid skin are the main causes of these aging changes. Tear trough groove with skeletonization of the lower orbital rim can not be corrected easily by the conventional lower blepharoplasty, but the augmentation of the volume, can be an effective method. Lower lids provide a well vascularized recipient site, which is vital for proper grafting of fat to occur. We treated tear trough groove with free fat graft of surgically removed orbital fat. Surgical excision of the fat pad and septal reinforcement with free fat graft below the levator labii superioris alaeque nasi muscle were performed to correct tear trough groove. This technique was performed in 29 consecutive individuals from October, 2001 to January, 2005. Palpebral bags and tear trough groove were corrected concomitantly and obtained a youthful attractive midface with no secondary hollowness of lower lid and irregularity. The overall results obtained were satisfactory without any complications. Recurrence of tear trough deformity due to grafted fat absorption was not noted during the 7 months of the follow-up period. The authors conclude that the procedure is safe and effective in selected patients.

• 대한두개안면성형외과학회지
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• 제13권2호
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• pp.125-129
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• 2012

Purpose: Methylmethacrylate is the most commonly used alloplastic material in cranioplasty. However during the polymerization of methylmethacrylate, a significant exothermic reaction takes place. This reaction may result in thermal injury to the brain tissue and other soft tissues. Also it is difficult to make three-dimensional methylmethacrylate implant that is perfectly matched to the defect during the operation time. We report on the molding technique of methylmethacrylate implant using plaster mold and the rapid prototyping model in cranioplasty. Methods: A 44-year-old male was referred to the department for severe frontal hollowness. He was involved in an automobile accident resulting in large frontal bone defect with irregular margin. The preformed patient-specific methylmethacrylate implant was made using plaster mold and the rapid prototyping model before the operative day. The methylmethacrylate implant was placed in the frontal defect and rigidly fixed with miniplates and screws on the operative day. Results: The operation was performed in an hour. In the 6 months follow-up period, there were no complications. Patient was satisfied with the results of cranioplasty. Conclusion: Safe cranioplasty was performed with the preformed patient-specific methylmethacrylate implant using plaster mold and the rapid prototyping model. The result of this method was satisfactory, aesthetically and functionally.

• Archives of Plastic Surgery
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• 제40권3호
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• pp.192-197
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• 2013

Background To construct a sophisticated three-dimensional framework, numerous modifications have been reported in the literature. However, most surgeons have paid little attention to the anatomical configuration of the concha and more to its deepness and hollowness, leading to unsatisfactory outcomes. Methods For a configuration of the concha that is definitely anatomical, the author further developed and employed the conchal bowl element, which has been used by several surgeons although the results have not been published elsewhere. The author constructed the conchal bowl element in one of three patterns according to the amount of available cartilages: one block, two-pieces, or a cymba bowl element only. A total of 20 patients underwent auricular reconstruction using a costal cartilage framework between 2009 and 2012. The 8 earliest reconstructions were performed without a conchal bowl element and the latter 12 with a conchal bowl element. The patients were followed up for more than 1 year. The aesthetic results were scored by evaluating characteristics involving the stability of the crus helicis, the conchal definition, and the smoothness of the helical curve. Results The ears reconstructed early without a conchal bowl element showed a shallow and one or two incompletely separated concha with an obliterated cymba conchal space. They also did not have a realistic or smooth curve of the helix because of an unstable crus helicis. However, ears reconstructed later with the concha bowl element showed a definite crus helicis, deep cymba conchal space, and smooth helical curve. Conclusions The construction of the conchal bowl element is simple, not time-consuming procedure. It is suggested that the conchal bowl element must be constructed and attached to the main framework for natural configuration of the reconstructed ear.

• Archives of Plastic Surgery
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• 제36권6호
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• pp.750-754
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• 2009

Purpose: The thoracodorsal vessels have been the standard recipient vessels for the majority of surgeons performing free abdominal flap breast reconstructions. Recently, the internal mammary vessels have been recommended as the first - choice recipient vessels for microvascular breast reconstruction. To approach the internal mammary vessel, 3rd or 4th rib cartilage excision is needed, but this method has some demerits - vessel injury, post operative pain and post operative chest hollowness. So, authors propose the approach method to the internal mammary vessel through intercostal space without rib cartilage resection. Methods: From November, 2008 to May, 2009, 13 patients underwent free abdominal flap breast reconstruction with approach to the internal mammary vessel through intercostal space without rib cartilage resection. Results: The mean patient age was 41.8 years, and the mean height was 159.3 cm. 11 patients underwent immediate breast reconstruction. Free DIEP flap reconstruction was performed in 7 patients, Free TRAM flap was performed in 5 patients, and Free SIEA flap was performed in 1 patient. Except 1 case, approach to the internal mammary vessel was took through 3rd intercostal space, and all width of intercostal space exceeded 1 cm. Conclusion: In the authors' experience, use of approach to the internal mammary vessels without rib cartilage resection method is safe and reliable to overcome demerits of rib cartilage resection method.

• 한국재료학회지
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• 제22권10호
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• pp.531-538
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• 2012

Hollow silica spheres were prepared by spray drying of precursor solution of colloidal silica. The precursor solution is composed of 10-20 nm colloidal silica dispersed in a water or ethanol-water mixture solvent with additives of tris hydroxymethyl aminomethane. The effect of pH and concentrations of the precursor and additives on the formation of hollow sphere particles was studied. The spray drying process parameters of the precursor feeding rate, inlet temperature, and gas flow rate are controlled to produce the hollow spherical silica. The mixed solvent of ethanol and water was preferred because it improved the hollowness of the spheres better than plain water did. It was possible to obtain hollow silica from high concentration of 14.3 wt% silica precursor with pH 3. The thermal conductivity and total solar reflectivity of the hollow silica sample was measured and compared with those values of other commercial insulating fillers of glass beads and $TiO_2$ for applications of insulating paint, in which the glass beads are representative of the low thermal conductive fillers and the $TiO_2$ is representative of infrared reflective fillers. The thermal conductivity of hollow silica was comparable to that of the glass beads and the total solar reflectivity was higher than that of $TiO_2$.

• 한국강구조학회 논문집
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• 제22권2호
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• pp.139-150
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• 2010

기둥은 하중 상태에 따라서 축하중과 횡하중 등에 영향을 받는 주부재로서 많이 사용되어지고 있다. 일반적으로 철근 콘크리트(Reinforced Concrete Column, R.C. Column)이 가장 많이 설계 및 시공되고 있으며, 그 밖에도 콘크리트 충전 강관(.Concrete Filled Tube, CFT) 기둥과 같은 복합재료의 기둥이 최근 현장에 많이 적용되어 건설이 진행되고 있는 실정이다. 철근 콘크리트 기둥의 자중의 감소와 사용 재료의 절감을 위하여, 기존의 기둥에 중공부를 두는 중공 R.C 기둥이 사용되고 있다. 중공 RC의 경우 동일 단면적을 갖는 일반 R.C기둥에 비하여 큰 단면이차모멘트를 갖게 되므로 더 효율적인 단면 활용이 가능하다. 그러나 위와 같은 장점이 있는 것과는 반대로, 중공 R.C 기둥은 내측면의 취성파괴로 인하여 낮은 연성 거동을 할 가능성이 높다. 이러한 내측면의 취성 파괴는 기둥 외측면의 경우 횡철근에 의해 구속되어 있으나, 내측면의 콘크리트에는 구속력이 작용하지 않는다. 이러한 단점을 극복하기 위하여 중공면에 구속력을 작용시켜, 콘크리트를 3축 구속 상태로 만들어 주어야 한다. 이를 해결하기 위해서 중공 R.C. 기둥 중공부에 강관을 삽입함으로서 중공 기둥 내의 콘크리트를 3축 구속 상태로 만들어주는 내부 구속 중공 R.C 기둥(Internally Concfined Hollow Reinforced Concrete, ICH R.C)이 기존연구자에 의해서 제시되어졌다.(Kang & Han, 2005) 본 연구에서는 ICH RC 기둥의 열전달 해석 및 비선형 재료모델 프로그램을 이용하여 내화 성능을 분석하였으며, 중공비, 피복콘크리트의 두께, 내부강관의 두께를 변수로 선정하여 매개변수를 수행함으로서 내부 구속 중공 RC 기둥의 내화 성능을 증가 시켜주는 인자를 찾아내고 분석하였다.

• Korean Chemical Engineering Research
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• 제46권6호
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• pp.1075-1080
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• 2008

구연산 및 융제를 함유하는 분무용액으로부터 분무열분해법에 의해 속이 빈 전구체 분말들을 합성하고, 후열처리 과정을 거쳐 미세 $Gd_2O_3:Eu$ 형광체를 합성하였다. 구연산은 전구체 분말들의 다공성을 증대시킴으로써 후열처리 후에 미세 형광체 합성이 가능하게 하였다. 구연산을 첨가하지 않은 분무용액으로부터 합성된 형광체는 수 마이크론 크기를 가졌다. 융제는 형광체 분말의 크기와 자외선 하에서의 발광세기를 증대시켰다. 여러 가지 용제 중 휘도가 우수한 초미세 $Gd_2O_3:Eu$ 형광체 합성에는 $Li_2CO_3$가 적절하였다. $Li_2CO_3$ 융제의 첨가량이 형광체의 3 wt% 이하일 때 소성 온도 $1,050^{\circ}C$ 및 $1,050^{\circ}C$에서 합성된 형광체들은 서브마이크론 크기를 가졌다. 소성 온도 $1,050^{\circ}C$에서 얻어진 형광체의 발광 세기는 소성온도 $1,050^{\circ}C$에서 얻어진 형광체의 124%였다.