• 한국건축시공학회지
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• 제10권5호
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• pp.129-135
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• 2010

2008년 7월 21일 고시한 국토해양부의 고강도 콘크리트 내화성능 관리기준에 따라 50MPa 이상의 고강도 콘크리트는 내화성능을 확인하여 건축물에 적용 가능하게 되었다. 이에 본 연구는 60, 80, 100MPa의 고강도 콘크리트를 대상으로 섬유종류, 섬유길이, 혼입량에 따른 콘크리트의 역학적 특성을 파악하고 아울러 피복두께에 따른 내화성능을 검토하여 국토해양부 관리기준에 만족하는지 파악하고, 초고층 건축물에 있어서 고강도 콘크리트를 적용하기 위한 내화성능 확보방안을 마련하고자 하였다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.489-492
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• 1997

The general pattern of adaptation in the appendicular skeleton with aging is that the subperiosteal apposition of bone occur along with endosteal absorption. This remodeling of diaphysis to a cylinder of larger diameter is hypothesized to serve a mechanical compensatory unction by increasing the moment of inertia as the cortex thins with aging. These findings is only true of the diaphysis of long bone. Measuring the area and inertia at each section of femur, the age-related change of proximal emur and diaphysis is observed. After screening by physical and radiological examination, 200 normal Korean adults divided 5 groups in both male and female based on age. Twenty persons were in each group. One femur in each person was analyzed using CT images. femur scanned with 60 to 80 slices and this images were digitized. Then 2-D images were reconstructed into 3-D images. Using the nonlinear method, normalization and interpolation technique, 7 locations of interest (trochanteric area: 1, 2 subtrochanteric area: 3, 4, isthmic area: 5, 6, 7) were determined. On the each cross section at each location, the area (total, cortical and medullary) and 5 inertia of moment were measured. The results were analyzed statistically. With aging, significant area change occurred mainly in diaphysis and female. In trochanteric area, no significant change was noted. With aging, total and medullary area were increased, but cortical area was not changed. In diaphysis, lateral bendingresistanceincreasedsignificantly. No inertia change was noted in trochanteric area. Anteroposterior bending resistance was constant with aging. In more than age 60, total area and medullary area were larger than that of others. Lateral bending resistance was higher especially in diaphysis. In diaphysis, with aging, the decreased properties is compensated with the increased lateral bending resistance by geometric remodeling. In trochanteric area, no compensation occur. With aging, especially in more than age 60, the higher rate of trochanteric fracture is expected.

• 비파괴검사학회지
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• 제33권1호
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• pp.63-68
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• 2013

Some essential components in nuclear power plants are periodically inspected using non-destructive examinations, for example ultrasonic, eddy current and radiographic examinations, in order to determine their integrity. These components include nuclear power plant items such as vessels, containments, piping systems, pumps, valves, tubes and core support structure. Steam generator tubes have an important safety role because they constitute one of the primary barriers between the radioactive and non-radioactive sides of the nuclear power plant. There is potential that if a tube bursts while a plant is operating, radioactivity from the primary coolant system could escape directly to the atmosphere. Therefore, in-service inspections are critical in maintaining steam generator tube integrity. In general, the eddy current testing is widely used for the inspection of steam generator tubes due to its high inspection speed and flaw detectability on non-magnetic tubes. However, it is not easy to analyze correctly eddy current signals because they are influenced by many factors. Therefore, the performance of eddy current data analysts for steam generator tubing should be demonstrated comprehensively. In Korea, the performance of steam generator tubing analysts has been demonstrated using the Qualified Data Analyst program. This paper describes the performance demonstration program for steam generator tubing analysts and its implementation results in Korea. The pass rate of domestic analysts for this program was 71.4%.

• 패션비즈니스
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• 제7권4호
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• pp.121-128
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• 2003

A new textile material, poly(trimethylene terephthalate) polymer, has been introduced to the textile industry. The structure of PTT is similar to the PET, while the tensile deformation and subsequent recovery property is better than that of PET. In this study, the physical and mechanical properties of textile woven fabrics made of PTT, PET, and nylon 6 yarns as the filling yarn were determined using the Kawabata Evaluation System (KES), including tensile, bending, shearing, compression, and surface related parameters. On top of these measurements, the subjective ratings by evaluators were performed on the fabric samples. From the examination of the stress-strain behavior of the yarn specimens focused on the recovery mode, it was evident that the PTT specimen developed lower stress at 3% elongation. The subsequent recovery curve showed that the PTT has less stress-decay rate than the other specimens, implying that the recovery behavior of the PTT is recommendable for the end-uses including stretchable textile materials, sports wears, etc. The KES bending rigidity(B) value of the PTT sample fabric was lower than that of the PET sample fabric. Subjective evaluation of the fabric samples by the evaluators on the descriptive word pair "soft - not soft" showed similar tendency with the KES B determination of the fabric samples.

• Journal of the Korean Wood Science and Technology
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• 제36권4호
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• pp.58-65
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• 2008

집성재의 구조부재로서의 이용에 있어서는 접합철물(connector)과 파스너(fastener)에 의한 접합이 대부분을 차지하고 있다. 이들 접합부의 역학적 거동은 파스너의 지압과 부재의 전단현상으로 설명할 수 있다. 집성재 내의 층재 구성상태에 따른 전단성능, 2면전단 핀접합부의 인발에 의한 전단성능, 실대 기둥-보 2면전단 핀접합부의 모멘트 저항성능을 검토하였다. 집성접착된 부위의 경우, 두 층재간의 보완작용에 의해 밀도 및 전단강도에 있어서도 적층효과를 발휘하였다. 소시험편의 전단강도를 이용한 핀접합부의 2면전단강도와 모멘트 저항성능을 예측할 경우 다소의 보정이 필요할 것으로 판단되었다. 기둥-보 접합부의 모멘트저항성능 예측은 소시험편 전단강도의 10%를 저감하여 이용하면 안전하게 예측가능한 것으로 판명되었다.

• 한국분말재료학회지
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• 제22권6호
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• pp.426-431
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• 2015

Microstructural examination of the Nb-Si-B alloys at Nb-rich compositions is performed. The Nb-rich corner of the Nb-Si-B system is favorable in that the constituent phases are Nb (ductile and tough phase with high melting temperature) and $T_2$ phase (very hard intermetallic compound with favorable oxidation resistance) which are good combination for high temperature structural materials. The samples containing compositions near Nb-rich corner of the Nb-Si-B ternary system are prepared by spark plasma sintering (SPS) process using $T_2$ and Nb powders. $T_2$ bulk phase is made in arc furnace by melting the Nb slug and the Si-B powder compact. The $T_2$ bulk phase was subsequently ball-milled to powders. SPS is performed at $1300^{\circ}C$ and $1400^{\circ}C$, depending on the composition, under 30 MPa for 600s, to produce disc-shaped specimen with 15 mm in diameter and 3 mm high. Hardness tests (Rockwell A-scale and micro Vickers) are carried out to estimate the mechanical property.

• Design & Manufacturing
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• 제2권2호
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• pp.29-32
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• 2008

A back light unit (BLU) is a key module of a thin film transistor liquid crystal display (TFT-LCD), frequently utilized in various mobile displays. In this study, we experimentally characterize transcription and optical properties of concave and convex microlens arrays (MLAs) of light guide plate (LGP) fabricated by injection molding with polycarbonate as a LGP substrate material. Nickel mold inserts were manufactured by electroforming on the MLA which was fabricated by the thermal reflow of photoresist microstructures patterned by UV-photolithography. For the case of convex microlens, the height of replicated microlens was less than that of the mold insert while maintaining almost the same microlens diameter of the mold insert as the location of the microlens is far from the gate. In contrast, for the concave microlens, the diameter of replicated microlens was larger than that of mold insert, while showing almost the same microlens height as the mold insert. From the optical examination of replicated convex and concave MLAs, it was found that a higher luminance of the LGP was achieved by the concave MLAs compared to the convex MLAs (about 30% enhancement in this case)due to the utilization of a larger amount of light provided by the light sources.

• 대한약침학회지
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• 제20권3호
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• pp.227-229
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• 2017

Fibrosis of skeletal muscle following acupuncture is an iatrogenic disorder. The present case illustrates a patient with a unilateral fibrotic formation on a thumb muscle after acupuncture injection therapy with red sage. The patient in the present case was a counter-terrorism police officer with right-handedness; he noted a palpable nodule three months after injection therapy at his left first dorsal interosseous in which the acupuncture point LI4 (He Gu) is located. He also found a reduction in the strength of his left pinch grip that noticeably affected his left handgun marksmanship. However, being ambidextrous in single-hand pistol shooting is an essential requirement for counter-terrorism police officers. Based on the patient's medical history and claims, no underlying disease or trauma was found to be associated with his current complaint. During physical examination, a fibrotic formation in his left first dorsal interosseous muscle was visualized by using diagnostic ultrasound; also, as confirmed with dynamometry, the strength of his left pinch grip was significantly lower than that of the right counterpart. Because acupuncture injection therapy has three components, antiseptic practices, the mechanical action of syringe insertion, and the pharmacological effect of the sterile herb extract, any one of the components may have contributed to the present adverse event. The first dorsal interosseous muscle is small in dimension and rather vascular; thus, it is not an ideal site for intramuscular injection. When a clinician needs to treat a patient by performing acupuncture at the LI4 acupoint and injecting a herbal extract simultaneously, the clinician should only mechanically stimulate the LI4 acupoint while injecting the herbal medicine into the LI14 (Bi Noe) acupoint on the same meridian, the LI14 acupoint being located in the distal portion of the deltoid muscle and being fairly close to the universally agreed upon site on the upper arm for safe administration of an injection.

• 한국건설관리학회논문집
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• 제8권6호
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• pp.207-215
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• 2007

본 연구는 학교건물의 유지관리를 위한 장기수선충당금 산정을 목적으로 수행되었으며, 이를 위해 서울 교육청에서 발주한 BTL 사업 대상 학교를 중심으로 사례를 선정하였다. 다음으로 사례 학교건물의 초기투자비용을 공종별로 분류한 후 장기 수선충당금을 산정하였다. 이렇게 산정된 공종별 장기수선충당금을 공동주택 장기수선충당금 산정방법과 연등가액 산정방법을 준용하여 비교 분석하였다. 위와 같은 목적과 방법에 따라 진행 된 본 연구의 결론을 요약하면 다음과 같다. 첫째: 사례 학교건물의 공종별 장기수선충당금의 비율을 정리하면 공사비용 대비 건축14.0%, 토목1.4%, 기계6.5%, 전기11.0%, 비품5.1%%, 기타1.0%의 분포를 나타냈다. 둘째: 산정된 공종별 장기수선충당금을 공동주택 장기수선충당금 산정방법과 연등가액 산정방법을 각각 이용하여 비용편차를 비교하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권5호
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• pp.301-312
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• 2020

In disease diagnostics and health surveillance, the use of saliva has potential because its collection is convenient and noninvasive. Over the past two decades, the development of salivary utilization for the early detection of cancer, especially oral cavity and oropharynx cancer has gained the interest of the researcher and clinician. Until recently, the oral cavity and oropharynx cancers are still having a five-year survival rate of 62%, one of the lowest in all major human cancers. More than 90% of oral cancers are oral squamous cell carcinoma (OSCC). Despite the ease of accessing the oral cavity in clinical examination, most OSCC lesions are not diagnosed in the early stage, which is suggested to be the main cause of the low survival rate. Many studies have been performed and reported more than 100 potential saliva biomarkers for OSCC. However, there are still obstacles in figuring out the reliable OSCC salivary biomarkers and the clinical application of the early diagnosis protocol. The current review article discusses the emerging issues and is hoped to raise awareness of this topic in both researchers and clinicians. We also suggested the potential salivary biomarkers that are reliable, specific, and sensitive for the early detection of OSCC.