• Archives of Plastic Surgery
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• 제39권3호
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• pp.209-215
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• 2012

Background : Among all facial fractures, nasal bone fractures are the most common, and they have been reduced by closed reduction (CR) for a long time. But several authors have reported suboptimal results when using CR, and the best method of nasal bone reduction is still being debated. We have found that indirect open reduction (IOR) through an endonasal incisional approach is a useful method for more accurate reduction of the nasal bone. Methods : A retrospective chart review was performed of 356 patients who underwent reduction of a nasal bone fracture in our department from January, 2006, to July, 2011. We treated 263 patients with IOR. We assessed patients' and doctors' satisfaction with surgical outcomes after IOR or CR. We evaluated the frequency of nasal bleeding owing to mucosal injury, and followed the surgical outcomes of patients who had simultaneous dorsal augmentation rhinoplasty. Results : According to the analysis of the satisfaction scores, both patients and doctors were significantly more satisfied in the IOR group than the CR group (P<0.05). Mucosal injury with nasal bleeding occurred much less in the IOR group (5.3%) than the CR group (12.9%). Dorsal augmentation rhinoplasty with IOR was performed simultaneously in 34 cases. Most of them (31/34) showed satisfaction with the outcomes. Conclusions : IOR enables surgeons to manipulate the bony fragment directly through the endonasal incisional approach. However, we propose that CR is the proper technique for patients under 16 and for those with comminuted nasal bone fractures because submucosal dissection in IOR can damage the growth or circulation of nasal bone.

• Journal of Magnetics
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• 제1권1호
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• pp.9-13
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• 1996

The effects of surface relaxation on surface and interface magnetism in Fe/Cr (001) are investigated using the highly precise all-electron total-energy full-potential linearized augmented plane wave method. The Fe-Cr interlayer spacing is deter-mined by total-energy calculation and it is found to be relaxed downward by 18%. For the relaxed system, the magnetic moment of surface Fe is highly suppressed to be $1.72\mu_B$compared to the unrelaxed case ($2.39\mu_B$). This reduction of magnetic moment is considered as a result of the enhanced hybridization between Fe-d and Cr-d states, which can be seen from the calculated density of states. This work suggests the importance of effect of relaxation to the surface and interface magnetism in Fe/Cr system.

• 한국표면공학회지
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• 제39권2호
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• pp.70-75
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• 2006

As technology advances, there is a demand for development of hard, solid lubricant coating. (Ti,Cr)N-$MoS_2$, films were deposited on SKD 11 tool steel substrate by co-deposition of $MoS_2$, with (Ti,Cr)N using a D.C. magnetron sputtering process. The influence of the $N_2/Ar$ gas ratio, the deposition temperature, the amount of $MoS_2$ in the films, and the bias voltage on the mechanical and the structural properties of the films were investigated. Wear tests were performed on the films deposited in various conditions.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.125-125
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• 2015

Ti-Al-Cr-N thin layer was prepared on Fe-Si thin sheet by arc ion plating to improve corrosion and mechanical properties. The compositions ratios of Fe : Cr : Al : Ti : Si : N of the thin layers at $500^{\circ}C$ was 1.24 : 0.56 : 36.82 : 32.72 : 0.59 : 28.07 [wt.%], respectively. The higher arc ion plating temperature was, the higher corrosion resistance and nano-hardness were observed due to chromium content. Corrosion potential and corrosion rate in artificial sea water of the coating layer were in the range of $-39mV_{SHE}$ and $2mA/cm^2$, respectively. Passivity was not observed in the artificial sea water. Nano-hardnesses of the thin layers was increased by adding Cr from 23.6 to 25.8 [GPa]. The friction coefficients and fatigue limits of the layers were 0.388, 0.031, respectively.

• 마이크로전자및패키징학회지
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• 제10권2호
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• pp.39-47
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• 2003

감광성 폴리이미드 위에 Cr을 RF 바이어스 스퍼터링 및 RF클리닝 후 DC 스퍼터링한 Cr/폴리이미드의 계면을 TEM으로 관찰하였다. RF power 밀도를 $0.13W/cm^2$에서 $2.12W/cm^2$로 증가시키면서 RF클리닝을 실시한 결과 폴리이미드의 에칭 양상이 둥근 모양에서 뾰족한 모양으로 변하였고 이방성 에칭으로 인해 거칠기가 크게 증가하였다. RF 바이어스 스퍼터링의 경우 RF power를 올리는 동안 RF 클리닝에 의해 폴리이미드가 에칭되었고, 에칭된 부분에 Cr이 증착된 계면을 단면으로 관찰한 결과 Cr과 폴리이미드가 겹쳐져서 혼합된 것처럼 보였다. 그러나 RF power를 올리는 시간을 단축시켜 Cr을 바이어스 스퍼터링했을 때에는 계면이 분명하게 관찰되어 Cr의 implantation이 일어나지 않았음을 알 수 있었다. RF 클리닝한 Cu/Cr/Polyimide를 필 테스트한 결과 짧은 시간의 RF 클리닝으로도 접착력이 크게 증가하였다. 그러므로 RF power를 올리는 동안 실시되었던 RF 클리닝이 RF 바이어스 스퍼터링한 Cr/Polyimide의 접착력 향상에 영향을 주었을 것으로 예상된다.

• 센서학회지
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• 제29권2호
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• pp.112-117
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• 2020

Xylene is a hazardous volatile organic compound that should be precisely measured to monitor indoor air quality. However, the selective and sensitive detection of ppm-level xylene using oxide-semiconductor gas sensors remains a challenge. In this study, pure and Cr-doped Co₃O₄ nanoparticles (NPs) were prepared using flame spray pyrolysis, and their gas-sensing characteristics to 5-ppm xylene at 250 ℃ were investigated. The 4 at% Cr-doped Co₃O₄ NPs exhibited a high gas response to 5-ppm xylene (resistance ratio to gas and air = 39.1) and negligible cross-responses to other representative and ubiquitous indoor pollutants such as ethanol, benzene, formaldehyde, carbon monoxide, and ammonia. In this paper, the enhancement of the gas response and selectivity of Co₃O₄ NPs to xylene by Cr doping was discussed in relation to the catalytic promotion of the gas-sensing reaction. This sensor can be used to monitor indoor xylene.

• 한국표면공학회지
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• 제54권5호
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• pp.285-293
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• 2021

High-entropy TiAlCrSiN nano-composite coating was designed to improve mold life for high temperature liquid molding. Alloy design, powder fabrication and single alloying target fabrication for the high-entropy nano-composite coating were carried out. Using the single alloying target, an arc ion plating method was applied to prepare a TiAlCrSiN nano-composite coating had a 30 nm TiAlCrSiN layers are deposited layer by layer, and form about 4 ㎛-thickness of multi-layered coating. TiAlCrSiN nano-composite coating had a high hardness of about 39.9 GPa and a low coefficient of friction of less than about 0.47 in a dry environment. In addition, there was no change in the structure of the coating after the dissolution loss test in the molten metal at a temperature of about 1100 degrees.

• 한국항해항만학회지
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• 제39권3호
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• pp.185-192
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• 2015

본 연구에서는 표면개질 활성탄을 이용하여 수용액상에서 혼합 중금속($Cr^{6+}$, $As^{3+}$)의 흡착능을 평가하였고 또한 표면개질 활성탄을 안정화제로 활용하여 해양오염퇴적물 내 As 및 Cr에 대하여 중금속 안정화 실험을 수행하였다. 실험결과, 흡착평형은 약 120분 후에 도달하였다. 또한, 중금속 등온 흡착 특성은 Freundlich 및 Langmuir 방정식을 이용하여 해석하였으며, 평형흡착 실험결과는 Langmuir 모델에 잘 부합되었고 $As^{3+}$ (28.47 mg/g)가 $Cr^{6+}$ (13.28 mg/g)보다 평형 흡착량이 많았다. $Cr^{6+}$인 경우, 용액의 pH가 6에서 10으로 증가함에 따라서 흡착량은 감소하는 것으로 나타났다. 하지만 pH 증가 변화에서 $As^{3+}$의 흡착량은 미미한 증가를 보였다. 안정화 방법은 오염퇴적물에 표면 개질한 활성탄 첨가 후 120일간 습윤 양생 하였다. 연속추출 실험결과로부터, 미처리 오염퇴적물과 비교해서 Cr 및 As의 이온교환, 탄산염, 산화물 및 유기물 존재 형태 합의 비는 각각 5.8% 및 7.6% 감소하였다.

• 대한본초학회지
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• 제39권1호
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• pp.39-47
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• 2024

Objectives : This study evaluates how various traditional Korean herbal medicines assess MUC5AC expression for esophageal mucosal defense and analyzes the associated mechanisms involved in inflammation. Methods : Forty types of traditional Korean herbal medicines were assessed for in vitro antioxidant activities, and the real-time PCR method was employed to analyze MUC5AC expression under pH 4.5 conditions in human esophageal epithelial cells (HET-1A). Eight types of Korean herbal medicines were evaluated for in vitro antioxidant activities, and Reactive oxygen specise (ROS) expression was analyzed under bile salt (480 𝜇M) and pH 5.5 conditions in human esophageal epithelial cells (HET-1A). Simulation experiments involving bile salts and acidity were conducted for one hour to assess the efficacy of four drugs, and the activities of Mitogen-activated Protein Kinase (MEK), Nuclear Factor Kappa B (NF-𝜅B), and Cyclooxygenase-2 (COX-2) were detected through Western blot analysis. Results : Compared to the Normal group, the Control group exhibited higher ROS generation. Such increased ROS levels were significantly reduced by four extracts: Citrus Unshius Pericarpium (CUP), Cnidium officinale Rhizoma (CR), Ginseng Radix (GR), and Linderae Radix (LR). The protein expression of COX-2 decreased with the treatment of LR, CUP, and CR. Particularly, CUP and CR exhibited superior effects compared to other groups in inhibiting the phosphorylation of NF-𝜅B. Conclusion : Based on the results obtained, we have identified drugs that inhibit oxidative stress and inflammation caused by bile acid in esophageal epithelial cells. Our future plans involve comparing and analyzing the efficacy of these herbal medicines through animal experiments.

• 한국세라믹학회지
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• 제39권1호
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• pp.79-85
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• 2002

플라즈마 용사코팅법을 이용하여 산화몰리브덴이 첨가된 크로미아 용사코팅층을 제조하여 MoO$_3$첨가에 따른 마찰, 마멸특성을 조사하였다. 상온 마찰, 마멸특성에 대한 실험을 위하여 왕복동 마멸시험장치를 사용하였다. 마멸시험후 마멸면의 물리적 변화와 화학적 조성의 변화를 SEM와 XPS를 통하여 살펴보았다. 산화몰리브덴이 첨가된 코팅층에서 마찰계수의 감소를 관찰할 수 있었다. 그러나 마멸량의 경우 산화몰리브덴이 첨가되지않은 크로미아 코팅층에서 가장 낮은 값을 나타내었다. 산화몰리브덴이 첨가된 코팅의 마멸된 표면에 마탈, 마멸에 유리한 보호막의 형성이 광범위하게 일어남을 알 수 있었다. 이러한 보호막에 산화몰리브덴이 MoO$_3$의 형태로 존재하는 것을 XPS분석을 통하여 알 수 있었다. 보호막에 산화몰리브덴의 존재가 마찰계수를 감소시키는 것으로 생각된다.