• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.393-404
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• 2020

This study examined the material properties of MDF manufactured using acetylated pinus radiata fibers against moisture and compared the properties with the fiberboard quality standards of KS F 3200. Since acetylated MDF shows very low moisture content, water absorption and thickness swelling than the quality standards, it is expected to have an excellent dimensional stability. The bending strength in wetting condition of the acetylated MDF reached approximately 70% of the bending strength in dry condition, making it suitable for the quality standards. The internal bond of the acetylated MDF in the wetting condition was higher than the minimum internal bond of the quality standards in the dry condition, showing a good water resistance. Since the water droplet contact angle of the acetylated MDF is larger than that of untreated MDF, it is determined that it contributes in improving the water resistance due to the low wettability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.5
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• pp.523-528
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• 2012

A bendable electronic module is developed for a mobile application by using a low-cost roll-to-roll manufacturing process. In the module, a thin silicon chip is embedded in a polymer-based encapsulating adhesive between flexible copper clad polyimide layers. A set of tests are conducted for the purpose of qualification: thermal shock, high temperature storage, and autoclave tests. During the autoclave test, delamination occurs at many places within the module layers. To investigate the failure mechanism, moisture diffusion analysis is conducted for the interior of the module under the autoclave test condition. For the analysis, the hygroscopic characteristics of the encapsulating materials are experimentally determined. Analysis results indicate the moisture saturation process in the interior of the module under the autoclave test condition.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.49-54
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• 2002

Purpose : To analyze the clinical results of treatment for the osteochondritis dissecans of femoral condyle by age, the type of lesion and method of treatment. Methods : From March 1991 to February 2000, 17 patients (20 cases) with osteochondritis dissecans of the femoral condyle were followed up over 1 year. Three patients had bilateral lesion. There were 12 cases with trauma history (9 cases with sports injury and 3 cases with direct trauma). The initial symptoms were pain, clicking, locking, giving way in the order of frequency, pain was revealed in all cases. Clinical evaluation of IKDC and Hughston method were used for subjective and objective function. Results : The number of male patient was 12, and the mean age was 19.8 year old (11$\~$50). The location of the lesion was 14 cases in medial femoral condyle and 6 cases in lateral femoral condyle. The arthroscopic findings of the lesion in 15 cases were as follows, early separation in 6 cases, partially detachment in 4 cases, and crators and complete detachment in 5 cases. 5 cases were treated with mutiple drilling and 5 cases with Herbert screw fixation, 3 cases with Herbert screw fixation and bone graft. In early stage, 7 cases were treated with conservative method. In the grading of Hughston score, 6 cases were graded as excellent, 9 cases as good, 15 cases were graded as good to excellent. Based on the IKDC scale, 1 case was graded as normal, 6 as nearly normal, and 10 as abnormal. Conclusions : The trauma seemed to be important factor in occurrence of osteochondritis dissecans of the femoral condyle. The clinical results of juvenile period showed better than adolescence and adult period, it is necessary to detect the lesion as soon as possible. The result of subjective evaluation was worse than the Hughston evaluation. It was caused by limiting involvement of sports activity and limited activity in the adolescence.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.107-113
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• 2010

In this study, the relative effects of low-chloride deicier(LCD) and two other deicing agents on the scaling of concrete were conducted in a series of tests at laboratory accordance with the ASTM C 672. The solutions concentration of deicers tested included 1, 4, 10%. Tap water was used as control. The amount of scaling was evaluated gravimetrically. As test result of deicer solution types, when applied to 4% solutions, surface scaling of concrete after 56 freeze-thaw cycles was produced significantly as about 9 times on LCD solution, as about 18 times on $CaCl_2$ solution, and as about 33 times on NaCl solution comparing with tap water. As test result of deicer solution concentrations, relatively low concentrations (of the 4% by weight) of deicer were produced more surface scaling than higher concentrations (of the 10% by weight) or lower concentrations (of the 1% by weight) of deicer. It show that the damaging concentration is of the order of 3~4% for previous research result. It appears that the mechanism of surface scaling is primarily physical rather than chemical. Also, the effect of chloride deicier types, freeze-thaw cycling, and air contents on the performance of concrete was experimentally investigated. The results show that the concrete specimens subjected to freeze-thaw cycling scaled more severely in exposure to deicing salt than those in non-exposure to deicing salt, weight losses of the specimens tested in exposure to deicing salt were twice as much as those tested in non-exposure to deicing salt. Relative dynamic modulus of elasticity of concrete specimens decreased more quickly in exposure to deicing salt than in non-exposure to deicing salt. Also, relative dynamic modulus of elasticity of concrete specimens in exposure to sodium chloride deicing salt was decreased more quickly comparing with exposure to LCD salt. It is also shown that the chloride contents according to concrete specimen depths was more largely in exposure to LCD salt. When concrete specimen is exposed to chloride deicing salts and freeze-thaw cycling, performance degradation in the entrained air concrete(AE concrete) retarded more considerably comparing with non-entrained air concrete(Non-AE concrete).

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.227-235
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• 2015

In recent years, owing to the frequent occurrence of natural disasters, the inspection and maintenance of structures have become increasingly important on a national scale. However, because most structural inspections are carried out manually, and due to the lack of objectivity in data acquisition, quantitative data are not always available. As a result, researchers are seeking ways to collect and standardize survey data using terrestrial laser scanning, thereby bypassing the limitations associated with visual investigations. However, field data acquired using a laser scanner have been required to measure changes in structure geometry resulting from passive deterioration. In this study, we demonstrate that it is possible to identify the processes of structural deterioration (e.g., efflorescence, leakage, delamination) using intensity data from terrestrial laser scanning. Additionally, we confirm the viability of automated classification of alteration type and objectification of the polygon area by establishing intensity characteristics. Finally, we show that our method is effective for structural inspection and maintenance.

• Journal of Conservation Science
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• v.34 no.5
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• pp.397-405
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• 2018

Currently, there are very few studies on Korean wall paintings. Therefore, this study discusses the current conditions of wooden paintings and the characteristics of the adhesive agent in the painting layer separation. Korean land pine was chosen as the support, while white oysters shells, orpiment, red ocher, Noerok, and azurite were used as pigments. With four adhesive agents, including animal glue, Gelidium, methyl cellulose, and PVAc (caparol binder), a comparative experiment was conducted, by dividing them into two concentrations, of 0.5% and 1.5%. The temperature, humidity, and ultraviolet rays, which are contributing environmental factors in cultural assets after fixing, were artificially investigated. After deterioration, observed color difference, fixing, and the surface. Results showed that the animal glue strongly fixing all the colored layers compared to the other adhesives; however, azurite had a partial change when used outdoors. With Gelidium, which functioned similar to animal glue, the azurite was affected by the ultraviolet rays; nevertheless, despite the variations in temperature and humidity, it had the best gripping force compared to the other adhesive agents. Methyl cellulose was glossy at a high concentration, and was relatively strong against rapid changes in temperature and humidity. PVAc significantly reduced the binding force, compared to other adhesive agents.

• Polymer(Korea)
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• v.36 no.3
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• pp.287-294
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• 2012

ZnAl-LDH(layered double hydroxide) (Zn:Al=2:1 mole ratio) modified with stearic acid (SA) or oleic acid (OA) was synthesized by a coprecipitation method and compounded to SAN polymer at various contents. All the SAN composites were manufactured by a co-rotating twin-screw extruder and subsequently injection molded into several specimen. Morphology, transparency, and thermal resistance of these composites were evaluated by TEM, XRD(X-ray diffractometry), UV-Vis spectrophotometry, and thermogravimetric analysis. SAN nanocomposites containing OA-$Zn_2Al$ LDH showed better optical transmittance than SAN nanocomposites containing SA-$Zn_2Al$ LDH. All the SAN nanocomposites containing OA-$Zn_2Al$ LDH or SA-$Zn_2Al$ LDH exhibited improvement of thermal resistance at second stage of thermal oxidation. These results were explained by the fact that the interaction between organic modifier and polymer performed an important role in the property improvement of polymer nanocomposites.

• Journal of the Korean Arthroscopy Society
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• v.14 no.2
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• pp.131-134
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• 2010

Inappropriate treatment of osteochondral fracture can cause osteoarthritis, pain, functional disorder. With large osteochondral fracture, reduction and fixation of the fragment using metal implant. However, when the bone fragment had less than 2mm, the fragment extracted because of difficulty of fragment fixation. Authors treated patients with fracture fragment thickness less than 2mm of osteochondral dissecans in medial femoral condyle and patella fracture using biodegradable meniscus screw, and then we obtained good result.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.3-3
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• 2010

소나무에서 추출해낸 천연유기유황(Natural Sulfur)의 의학적 가치는 1972년 Jacob 박사와 Herschler 박사가 오래곤 과학대학에서 천연식이유황(Natural Sulfur/MSM)을 가지고 표피조직에 미치는 영향을 구명하면서 keratin 단백질에 대한 연구가 활성화 되기 시작하였다. 세포내 골격물질은 크게 형태와 조성에 따라서 actin microfilament, microtubule, 그리고 intermediate filament(IF)로 구분된다. keratin의 특성은 keratin intermediate family중에서 K17 IF가 새로운 기능을 나타내는데 피부세포의 성장에 핵심적인 조절 역할을 한다는 사실이 밝혀 지면서 Dr. Pierre A. Coulombe(The Johns Hopkins University School of Medicine)연구실은 브로컬리와 같은 십자화과 식물 등에 과량 존재하는 항산화 및 항암물질인 sulforaphane이 K17의 발현을 특이적으로 증가시킨다는 것을 알아내어 피부박리와 같은 피부손상을 기능적으로 복구시킬수 있음을 확인하였다. 현재는 수포성 표피박리증 환자군의 많은 부분을 차지하는 K14 돌연변이와 동일한 유전적 변형을 일으킨 생쥐모델을 이용한 약물 효과 검증과 전 임상단계의 인체실험을 함께 진행중에 있다. Mark E. Van Dyke 박사(Wake Forest Institute for Regenerative Medicine Medical Center)는 인간의 머리털에서 유래된 keratin으로 외상에 의한 신경 절단이나 압좌(압박손상)는 현재 다른 부위의 신경을 잘라 이식하거나 절단된 신경 양끝을 인공도관(conduit)으로 연결해 신경재생을 유도하는 미세수술을 시행하게 되는데, 신경재생을 유도하는 도관에 keratin을 주입하면 신경이식과 맞먹는 신경재생 성공률을 기대할 수 있다고 하였다. 앞으로는 동물성 keratin뿐만 아니라 식물성 keratin도 함께 연구할 필요가 있다. 동물성 keratin의 농업적 이용은 가금류 깃털의 keratin을 축출하여 친환경 육묘용 용기를 만드는데 있다. 이 용기는 자연조건에서 생분해될 수 있는 특성을 갖고 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.66-74
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• 2016

This study examined the effects of nursing information provision using a booklet on the patients' anxiety and uncertainty with an endoscopic submucosal dissection before the procedure, which is a non-equivalent controlled pre-post test designed study. Twenty three patients in a control group received the existing intervention, which is the general education prior to the procedure without standardized format as well as an oral explanation, and 23 patients in the experimental group received nursing information with a booklet developed by the investigator of this study. The collected data were analyzed using a ${\chi}^2$ test and Fisher's exact t-test on SPSS 21.0. The experimental group reported significantly lower anxiety (t=3.319, p=.002) and anxiety behavioral responses (t=3.508, p=.001) than those in the control group. There were no significant differences in uncertainty between the groups (t=.745, p=.460). Nursing information using the booklet is a useful nursing intervention to reduce the anxiety of patients with endoscopic submucosal dissection before the procedure.