• 조명전기설비학회논문지
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• 제13권4호
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• pp.82-86
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• 1999

본 연구에서는 푸로브법과 교류중첩법을 이용하여 고주파 유도결합 플라즈마에서 전자에너지 분포함수를 측정하였다. 실험조건은 압력 10∼40[mTorr], 입력파워는 100∼600[W]이고, 가스유량은 3∼12[sccm]이며, 전자에너지 분포함수의 공간분포 측정에 있어서 아스펙트비(R/L)는 2로 하였다. 전자에너지 분포함수는 압력 및 입력파워에 대하여 강한 의존성을 나타내었고, 가스유량이 증가할수록 증가 하였다. 전자에너지 분포함수의 반경방향 분포는 플라즈마 중심에서 최대가 되었다. 전자에너지 분포함수의 축방향 분포는 석영창과 기판 사이의 중심에서 최대가 되었다. 이러한 결과는 고주파 유도결합 플라즈마의 생성 메커니즘 이해와 간단한 ICP(Inductively Coupled Plasma) 모델링 응용에 기여할 수 있을 것이다.

• Restorative Dentistry and Endodontics
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• 제42권1호
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• pp.54-59
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• 2017

Objectives: The purpose of this study was to compare the antibacterial activity of urushiol against Enterococcus faecalis (E. faecalis) to that of NaOCl. Materials and Methods: The canals of thirty two single rooted human teeth were instrumented with Ni-Ti files (ProTaper Next X1, X2, X3, Dentsply). A pure culture of E. faecalis ATCC 19433 was prepared in sterile brain heart infusion (BHI) broth. The teeth were submerged in the suspension of E. faecalis and were incubated at $37^{\circ}C$ for 7 days to allow biofilm formation. The teeth were randomly divided into three experimental groups according to the irrigant used, and a negative control group where no irrigant was used (n = 8). Group 1 used physiologic normal saline, group 2 used 6% NaOCl, and group 3 used 10 wt% urushiol solution. After canal irrigation, each sample was collected by the sequential placement of 2 sterile paper points (ProTaper NEXT paper points, size X3, Dentsply). Ten-fold serial dilutions on each vials, and 100 µL were cultured on a BHI agar plate for 8 hours, and colony forming unit (CFU) analysis was done. The data were statistically analyzed using Kruskal-Wallis and Mann-whitney U tests. Results: Saline group exhibited no difference in the CFU counts with control group, while NaOCl and urushiol groups showed significantly less CFU counts than saline and control groups (p < 0.05). Conclusions: The result of this study suggests 10% urushiol and 6% NaOCl solution had powerful antibacterial activity against E. faecalis when they were used as root canal irrigants.

• 한국가스학회지
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• 제11권2호통권35호
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• pp.55-59
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• 2007

본 논문은 평판강재를 소성적으로 가공하고, 이것을 용접으로 연결하여 제작한 LPG 용기에 대한 강도 안전성을 고찰하고자 한다. 용기의 강도 안전성은 유한요소해석법을 사용하여 LPG 용기 구조물에서 발생되는 응력분포를 해석함으로써 안전성에 대한 결과를 얻을 수 있다. FEM 해석결과에 의하면, 내압시험을 위한 가스압력 $31kg/cm^2$은 LPG 용기의 상부경판의 프레스 가공 부근에서 국부적인 집중응력이 발생하고, 여기서 발생된 최대응력은 용기 소재의 항복강도를 넘어서는 것으로 나타났다. 따라서 현재의 내압시험 검사방법은 압력용기의 피로손상을 증가시키고 수명을 단축하는 원인으로 작용할 수 있다는 결과를 보여주기 때문에 재검토되어야 하고, 빠른 시일에 개정되어야 할 것이다. 반면에 충전압력 $9kg/cm^2$와 기밀시험 압력 $18.6kg/cm^2$에 의한 용기의 충전과 검사기준에 대한 해석은 LPG 강재용기의 안전성이 비교적 높다는 결과를 제시하고 있다.

• 한국운동역학회지
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• 제24권2호
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• pp.167-172
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• 2014

The purpose of this study was to investigate walking standard time and joint powers of the lower extremities on the changes of illuminations in the elderly women. Ten older women ($70.90{\pm}3.28$ years, $154.70{\pm}3.47$ cm, $53.80{\pm}5.39$ kg) with normal vision and no gait disabilities participated in this study. All the experiments were performed on a level walkway from low to high lighting (six conditions). A 3-dimensional motion capturing system, force-plate, and EMG were used to acquire and analyze walking motion, force, and muscle activity data; the sampling frequency was 100 Hz, 1000 Hz and 1000 Hz respectively. To test the differences on walking standard time and joint powers of the lower extremities between the six lighting conditions, one-way repeated ANOVAs were evaluated. The following results were drawn: First, mean standard time was about 1.3 sec/stride, and velocities were smaller with lighting increasing except 100 Lx. Second, the joint power patterns of ankle and knee were not consistent, but only hip joint power was a greatest in 6 Lx and a smallest in 400 Lx. Third, standard times(100 Lx<300 Lx, 400 Lx) were statistically significant, and hip joint max powers (100 Lx>others) were also statistically significant. But ankle and knee joint max power were not statistically significant. These results showed that standard times from low to high lighting were not consistent, and hip joint of 100 Lx has a greatest rotational torque. We suggested that gait strategies of them as to changing illuminations were not consistent and findings may represent a lack of adaptability in the elderly women.

• 비파괴검사학회지
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• 제32권5호
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• pp.469-483
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• 2012

인체 연조직에서 기계적인 진동의 전달 특성은 조직의 탄성 특성에 의존한다. 연조직의 진동 특성으로부터 암이나 종양을 진단할 수 있기 때문에 진동의 전달 특성에 대한 연구는 중요한 의미를 가진다. 이 논문은 연조직의 표면에 위치하는 여러 형태의 응력 진동원에 의해 연조직 내에 발생되는 변위 패턴을 분석하고 비교하였다. 진동원으로는 수직하중, 접선하중, 그리고 면외전단하중이 고려되었다. 점탄성 단일층에서의 변위에 대한 이론적 표현식을 구하였고, 수치계산은 반공간 및 무한평판조직에서 수행되었다. 그리고 유한크기조직에서의 변위패턴을 유한요소법으로 시뮬레이션하였다. 응력 형태, 진동원 크기 및 주파수, 그리고 경계면이 변위에 미치는 영향이 분석되었다.

• Clinics in Orthopedic Surgery
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• 제10권4호
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• pp.455-461
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• 2018

Background: Surgical-site, multimodal drug injection has recently evolved to be a safe and useful method for multimodal pain management even in patients with musculoskeletal trauma. Methods: Fifty consecutive patients who underwent plating for mid-shaft and distal clavicular fractures were included in the study. To evaluate whether surgical-site injections (SIs) have pain management benefits, the patients were divided into two groups (SI and no-SI groups). The injection was administered between the deep and superficial tissues prior to wound closure. The mixture of anesthetics consisted of epinephrine hydrochloride (HCL), morphine sulfate, ropivacaine HCL, and normal saline. The visual analogue scale (VAS) pain scores were measured at 6-hour intervals until postoperative hour (POH) 72; stress biomarkers (dehydroepiandrosterone sulfate [DHEA-S], insulin, and fibrinogen) were measured preoperatively and at POH 24, 48, and 72. In patients who wanted further pain control or had a VAS pain score of 7 points until POH 72, 75 mg of intravenous tramadol was administered, and the intravenous tramadol requirements were also recorded. Other medications were not used for pain management. Results: The SI group showed significantly lower VAS pain scores until POH 24, except for POH 18. Tramadol requirement was significantly lower in the SI group until POH 24, except for POH 12 and 18. The mean DHEA-S level significantly decreased in the no-SI group ($74.2{\pm}47.0{\mu}g/dL$) at POH 72 compared to that in the SI group ($110.1{\pm}87.1{\mu}g/dL$; p = 0.046). There was no significant difference in the insulin and fibrinogen levels between the groups. The correlation values between all the biomarkers and VAS pain scores were not significantly different between the two groups (p > 0.05). Conclusions: After internal fixation of the clavicular fracture, the surgical-site, multimodal drug injection effectively relieved pain on the day of the surgery without any complications. Therefore, we believe that SI is a safe and effective method for pain management after internal fixation of a clavicular fracture.

• Hip & pelvis
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• 제30권4호
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• pp.269-275
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• 2018

Purpose: The purpose of this study is to describe a method of inserting cement in the femoral head before fixation with dynamic hip screw to prevent screw cut out due to osteoporosis and to evaluate its clinical outcome in these patients. Materials and Methods: In this prospective study, 30 patients aged 60 years and older with intertrochanteric fracture were included. Bone mineral density was measured. After reaming of the femoral head and neck with a triple reamer and polymethyl methacrylate, bone cement was introduced into the femoral head using a customized nozzle and a barrel fitted on a cement gun. A Richard screw was inserted and the plate was fixed over the femoral shaft. Patients were mobilized and clinical outcomes were rated using the Salvati and Wilson's scoring system. Results: More patients included in this study were between 66 and 70 years old than any other age group. The most common fracture according to the Orthopaedic Trauma Association classification was type 31A2.2 (46.7%). The T-score was found to be $-2.506{\pm}0.22$ (mean${\pm}$standard deviation); all patients were within the range of -2.0 to -2.8. The duration of radiological union was $13.67{\pm}1.77$ weeks. Salvati and Wilson's scoring at 12 months of follow up was $30.96{\pm}4.97$. The majority of patients were able to perform their normal routine activities; none experienced implant failure or screw cut out. Conclusion: Bone cement augmentation may effectively prevent osteoporosis-related hardware complications like screw cut out in elderly patients experiencing intertrochanteric fractures.

• 대한소아치과학회지
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• 제48권3호
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• pp.352-358
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• 2021

Molar-incisor malformation (MIM)은 치관은 정상이나 치근의 비정상적인 형태를 보이는 것이 특징적이다. 제1대구치에 가장 많이 발생하며, 제2유구치나 상악 중절치도 때때로 이환된다. 이 증례 보고에서는 제1대구치를 포함해, 제2유구치에 MIM이 나타난 환자의 증례를 보고하고, 치근이 건전하게 발거된 제2유구치의 micro computed tomography (CT)를 이용한 형태학적 분석을 시행하였다. 발거된 치아에서는 MIM의 외형적 특징인 치관 - 치근 이행부의 cervical constriction을 육안상으로 확인할 수 있었으며, micro CT 분석에서 백악법랑경계부의 광화된 부위 (Cervical Minelarized Diaphragm), 많은 부근관과 막힌 근관 등의 복잡한 근관 형태, 근관 내 석회화 물질, 영구치에 비해 상대적으로 협착된 치관부 치수강이 관찰되었다.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.327-337
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• 2021

Fibrinolytic enzymes with a direct mechanism of action and safer properties are currently requested for thrombolytic therapy. This paper reports on a new enzyme capable of degrading blood clots directly without impairing blood coagulation. This enzyme is also non-cytotoxic and constitutes an alternative to other thrombolytic enzymes known to cause undesired side effects. Twenty-four Bacillus isolates were screened for production of fibrinolytic enzymes using a fibrin agar plate. Based on produced activity, isolate S127e was selected and identified as B. subtilis using the 16S rDNA gene sequence. This strain is of biotechnological interest for producing high fibrinolytic yield and consequently has potential in the industrial field. The purified fibrinolytic enzyme has a molecular mass of 27.3 kDa, a predicted pI of 6.6, and a maximal affinity for Ala-Ala-Pro-Phe. This enzyme was almost completely inhibited by chymostatin with optimal activity at 48℃ and pH 7. Specific subtilisin features were found in the gene sequence, indicating that this enzyme belongs to the BPN group of the S8 subtilisin family and was assigned as AprE127. This subtilisin increased thromboplastin time by 3.7% (37.6 to 39 s) and prothrombin time by 3.2% (12.6 to 13 s), both within normal ranges. In a whole blood euglobulin assay, this enzyme did not impair coagulation but reduced lysis time significantly. Moreover, in an in vitro assay, AprE127 completely dissolved a thrombus of about 1 cc within 50 min and, in vivo, reduced a thrombus prompted in a rat tail by 11.4% in 24 h compared to non-treated animals.

• Smart Structures and Systems
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• 제28권6호
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• pp.745-760
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• 2021

Dynamic buckling of structure is one of the failure modes that needs to be considered since it may result in catastrophic failure of the structure in a short period of time. For a thin fiber-reinforced polymer (FRP) plate under compression, buckling is an inherent hazard which will be intensified by the existence of defects like holes, cracks, and delamination. On the other hand, the growth of the delamination is another prime concern for thin FRP plates. In the current paper, reinforcing the plates against buckling is realized by using SMA wires in the form of stitches. A numerical framework is proposed to simulate the dynamic instability emphasizing the effect of the SMA stitches in suppressing delamination growth. The suggested algorithm is more accurate than the other methods when considering the transformation point of the SMA wires and the modeling of the cohesive zone using simple and yet reliable technique. The computational design of the method by producing the line by line orders leads to a simple algorithm for simulating the super-elastic behavior. The Lagoudas constitutive model of the SMA material is implemented in the form of user material subroutines (VUMAT). The normal bilinear spring model is used to reproduce the cohesive zone behavior. The nonlinear finite element formulation is programmed into FORTRAN using the Newmark-beta numerical time-integration approach. The obtained results are compared with the results obtained by the finite element method using ABAQUS/Explicit solver. The obtained results by the proposed algorithm and those by ABAQUS are in good agreement.