• Membrane and Water Treatment
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• 제14권2호
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• pp.85-93
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• 2023

Membrane separation is widely used for several applications such as water treatment, membrane reactors and climate change. Cross-linked organic-inorganic hybrid polyvinylidene fluoride (PVDF) / Tetraethyl orthosilicate (TEOS) was adopted for the preparation of optimized hollow membrane (HFM) for membrane distillation or other low pressure separators for mechanical properties and permeability under varying pretreatment schemes. HFMs were prepared on semi-pilot membrane fabrication system. Novel adopted post-treatment schemes involved soaking in glycerol, magnesium sulphate (MgSO₄), sodium hypochlorite (NaOCl), and isopropanol for different durations. All fibers were characterized for morphology using a scanning electron microscope (SEM), surface roughness using atomic force microscope (AFM), elemental composition by examining Energy Dispersive Spectroscopy (EDS), water contact angle (CA°) and porosity. The performance of the fibers was evaluated for pure water permeation flux (PWF). Post-treatment with MgSO₄ gave the highest both tensile modulus and flux. Assessment of properties and performance revealed comparable results with other organic-inorganic separators, HF or flat. In spite of few reported data on post treatment using MgSO₄ in presence of TEOS, this proves the potential of low cost treatment without negative impact on other membrane properties. The flux is also comparable with hypochlorite which manifests substantial precaution requirements in actual industrial use.The relatively high values of flux/bar for sample treated with TEOS, post treated with MgSO₄ and hypochlorite are 88 and 82 LMH/bar respectively.

• 한국재료학회지
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• 제23권1호
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• pp.18-23
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• 2013

In this study, the effects of cryogenic treatment cycles on the residual stress and mechanical properties of 7075 aluminum alloy (Al7075) samples, in the form of a tube-shaped product with a diameter of 500 nm, were investigated. Samples were first subjected to solution treatment at $470^{\circ}C$, followed by cryogenic treatment and aging treatment. The residual stress and mechanical properties of the samples were systematically characterized. Residual stress was measured with a cutting method using strain gauges attached on the surface of the samples; in addition, tensile strength and Vickers hardness tests were performed. The detailed microstructure of the samples was investigated by transmission electron microscopy. Results showed that samples with 85 % relief in residual stress and 8% increase in tensile strength were achieved after undergoing three cycles of cryogenic treatments; this is in contrast to the samples processed by conventional solution treatment and natural aging (T4). The major reasons for the smaller residual stress and relatively high tensile strength for the samples fabricated by cryogenic treatment are the formation of very small-sized precipitates and the relaxation of residual stress during the low temperature process in uphill quenching. In addition, samples subjected to three cycles of cryogenic treatment demonstrated much lower residual stress than, and similar tensile strength compared to, those samples subjected to one cycle of cryogenic treatment or artificial aging treatment.

• 열처리공학회지
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• 제18권1호
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• pp.46-53
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• 2005

• 대한소아치과학회지
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• 제45권2호
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• pp.215-224
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• 2018

인구통계적 변화 및 사회 경제적 변화 등으로 인해 최근 몇십 년간 소아치과는 환자 분포와 진료 양상에 많은 변화가 있었다. 본 연구는 이러한 변화의 양상을 파악하기 위해 시행되었다. 2006년부터 2015년까지 서울대학교 치과병원 소아치과에 내원한 모든 환자를 대상으로 하여 환자분포 및 진료 현황에 대한 정보를 분석하였다. 조사 결과 전체 환자 중 초진 환자의 비율은 증가하였고, 초진 환자의 평균 연령은 감소하였다. 연도별 진료 현황을 조사한 결과 2006년에는 수복치료, 예방치료, 교정치료, 외과치료, 치수치료 순으로 빈도가 높았다. 이후 예방치료는 크게 증가했고, 수복치료는 감소하였고, 치수치료 및 외과치료는 비슷하게 유지되었다. 교정치료는 2009년까지 증가하였으며 이후로는 감소하였다. 그 결과 2015년에는 예방치료, 수복치료, 교정치료, 외과치료, 치수치료 순으로 많이 시행되었다. 진정법과 전신마취 시행 건수를 년도별로 조사한 결과 2011년 이후 전신마취 시행이 크게 증가하였으며, 진정법은 2010년 크게 증가하였다가 이후 감소하여 매년 200건 정도가 시행되었다. 전체 진료 항목 중 급여 진료는 2009년까지 감소하였으며, 이후 증가하였다.

• 열처리공학회지
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• 제6권4호
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• pp.185-193
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• 1993

The effect and Condition of heat treatment on the tensile strength of welded joint was investigated in 300 grade 18% Ni-Co-Mo-Ti maraging steel sheets welded with electron beam. A good tensile strength of welded joint was obtained by following heat treatment cycle ; At $1100^{\circ}C$ the specimen was high temperature solution treated for 1 hour and then it was repeated solution treated at $900^{\circ}C$, $820^{\circ}C$ for 1 hour respectively to recrystallize the coarsened ${\gamma}$ grain. These heat treatment cycle was completed by an final aging heat treatment at $480^{\circ}C$ for 4 hour. Moreover, dissolution of dendrite, a significant decrease in seregation of Mo, Ti in weld metal were observed and also the coarsened ${\gamma}$ grain formed at $1100^{\circ}C$, $1200^{\circ}C$ changed to fine grain due to the effect of recrystallization.

• Journal of Oral Medicine and Pain
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• 제47권3호
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• pp.126-134
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• 2022

Purpose: This study aimed to propose an efficient treatment approach for infection with different candida species. Methods: Fifty-three patients who presented with a chief complaint of oral mucosal pain and exhibited positive candida culture findings were divided into two groups (Candida albicans and non-albicans). Pain, mucosal manifestations, salivary flow rates, durations of disease and treatment, and responses to treatment (nystatin and clonazepam) were investigated in both groups. Results: Patients in the C. albicans group exhibited more prominent clinical characteristics (erythematous lesions, tongue coatings, and hyperalgesia) than those in the non-albicans group. In total, 70% of patients in the non-albicans group showed no abnormalities in the oral mucosa. Patients in the C. albicans group showed increased resistance to nystatin treatment compared to those in the non-albicans group, especially with longer disease durations. The patients resistant to nystatin treatment showed positive responses to clonazepam. Conclusions: Patients with oral mucosal pain should be tested for the presence of Candida, even in the absence of mucosal abnormalities, especially those infected with non-albicans species. If no response to antifungal therapy is observed, treatment with clonazepam should be initiated, especially in patients infected with C. albicans.

• 열처리공학회지
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• 제15권5호
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• pp.238-240
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• 2002

• Membrane and Water Treatment
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• 제9권4호
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• pp.233-243
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• 2018

In this manuscript, $35m^3/d$ NF unit was designed and applied for surface water treatment of the River Nile water. Intake of Embaba drinking water treatment plant was selected to install that unit at since; it has the lowest water quality index value through the examined 6 sites in greater Cairo area. The optimized operating conditions were feed and permeate flow, 40 and $7m^3/d$, feed pressure 2.68 bar and flux rate $37.7l/m^2h$. The permeate water was drinkable according to Egyptian Ministerial decree 458/2007 for the tested parameters (physic-chemical, heavy metals, organic, algal, bacteriological and parasitological). Single and double sand filters were used as pretreatment for NF membranes but continuous clogging for sand filters moved us to use UF membrane as pretreatment for NF membrane.

• 대한수의학회지
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• 제62권3호
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• pp.22.1-22.4
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• 2022

This study reports the efficacy of the vasodilator sodium nitroprusside (SNP), for treatment of acute cardiogenic pulmonary edema in dogs. For this study, the patients were divided into the SNP only treatment group, the SNP, furosemide and dobutamine treatment group, and non-SNP treatment group. Seven dogs, 6 dogs and 2 dogs were favorable responders in SNP only group, group with SNP, furosemide and dobutamine and non-SNP treatment group, each. The results of this study suggest that SNP can be an effective alternative therapy for dogs with acute cardiogenic pulmonary edema.

• Journal of Chest Surgery
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• 제47권6호
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• pp.499-503
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• 2014

Atrial fibrillation (AF) is the most common type of arrhythmia and has a large global burden. In general, treatment of AF is based on medication and consists of rate and rhythm control together with anticoagulation. However, surgical treatment may be required in patients with AF combined with organic valvular heart diseases or who experience recurrence despite medication. In addition, surgical treatment plays a role in the treatment of lone AF. This article reviews the various surgical treatment options for AF.