• Journal of Periodontal and Implant Science
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• 제46권1호
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• pp.46-56
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• 2016

Purpose: We evaluated the efficacy of a mouthwash containing potassium nitrate ($KNO_3$) as its main component, along with sodium fluoride (NaF) and cetylpyridinium chloride (CPC). The primary endpoint was the relief of dentin hypersensitivity (DH) against the cold stimuli. The effects on other DH tests and periodontal inflammation were also evaluated. Methods: We used a single-center, double-blind, placebo-controlled, randomized design. A total of 82 patients with DH (40 in the test group, 42 placebo controls) were analyzed using visual analog scales (VASs) for a cold test, a tactile test, a compressive air test, and self-reported pain during daily activities, as well as clinical parameters including plaque index, gingival index, modified sulcular bleeding index (mSBI), gingival recession, and probing depth, which were collected at baseline and after four and six weeks of mouthwash use. Results: VAS scores for cold sensations, tactile sensations, the compressive air test, and self-reported pain significantly decreased from baseline during the six weeks in both groups (P<0.01), and no significant differences between the groups were found. In male patients (10 in the test group and 7 in the control group), both groups showed significant reductions in VAS scores for the cold test over the six weeks, and greater reductions were found in the test group than in the control group between four and six weeks (P=0.01) and between baseline and six weeks (P<0.01). In addition, the mSBI in the test group significantly decreased from baseline during the six weeks (P<0.01), and the changes at four and six weeks from baseline were significantly greater in the test group compared to the control group (P=0.03 and P=0.02, respectively). Conclusions: A mouthwash containing a mixture of $KNO_3$, NaF, and CPC reduced DH and gingival inflammation, however, the efficacy was comparable to the control group.

• 한국재료학회지
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• 제25권10호
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• pp.547-551
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• 2015

The present study prepared molybdenum trioxide ($MoO_3$), the most important intermediate of molybdenum metal, by using a fluidized bed reactor for the thermal decomposition of ammonium molybdate (AM) in the presence of an air flow. During the process of fluidizing the sample inside the reactor, the reaction time and temperature were optimized with a close analysis of the X-ray diffraction (XRD) data and with thermogravimetric analysis (TGA). In particular, the temperature level, at which the AM decomposition is completed, is very important as a primary operating parameter. The analysis of the XRD and TGA data showed that the AM decomposition is almost completed at ${\sim}350^{\circ}C$ with a reaction time of 30 min. A shorter reaction time of 10 min. required a higher reaction temperature of ${\sim}500^{\circ}C$ with the same air flow rate to complete the AM decomposition. A sharp rise in the decomposition efficiency at a temperature ranging between 320 and $350^{\circ}C$ indicated a threshold for the AM decomposition. The operating conditions determined in this study can be used for future scale-ups of the process.

• 한국건축시공학회지
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• 제18권1호
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• pp.9-15
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• 2018

지구상에 존재하는 라돈가스는 바위, 토양, 건축자재 등에서 방출되는 1급 발암물질로 유일한 기체상으로 존재하고 있다. 공기에 비해 무겁고 분자량이 커 하부에 가라앉아 있지만 이동성이 크다. 라돈가스는 특성상 실외에서 대기에 확산되지만 밀폐되고 환기가 어려운 실내공간의 농도는 수천 배까지 증가할 수 있다. 이러한 라돈가스의 위해성을 해결하기 위해 안트라사이트를 활용한 경화체의 라돈가스 저감 특성과 더불어 실내 마감재로 사용할 수 있는 기초 성능평가를 진행하였다. 기존 여과재로 사용된 안트라사이트를 사용하여 경화체를 제작하였으며, 기존 실내에서 사용된 건축자재 중 라돈을 방출하는 석고보드를 대체할 수 있는 시험을 진행하였다. 결합재로는 경소 마그네시아를 사용하였고, 경소마그네시아의 경화를 위해 염화마그네슘을 사용하였다. 흡착재로 사용된 안트라사이트의 치환율은 0, 10, 20, 30, 40, 50 (%)로 총 6수준으로 진행하였으며,W/B는 40%로 고정하였다. 시험항목은 휨파괴 하중, 열전도율, 라돈가스 농도를 진행하였으며, 양생조건은 항온항습 양생(습도 $80{\pm}5%$, 온도 $20{\pm}2^{\circ}C$)으로 진행하였다.

• 조명전기설비학회논문지
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• 제13권4호
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• pp.87-95
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• 1999

새로운 종류의 고체상태 대전력, 고속전자장치 즉 광전도전력스위치(PCPS)의 가장 큰 문제점은 평균전계하의 표면에서 스위치 섬락의 대부분이 반도체의 벌크파괴보다 낮다는 것이다. 이러한 문제를 극복하고 고밀도 고체 전력 스위치에 사용할 수 있는 유일한 방법이 고체 절연물로 표면을 페시베이션(Passivation)하는 것이다. 본 실험에서 Silicon의 절연내력은 진공중에서 10[kV/cm]에서 심하게 열화되어졌고, 기중에서 30[kV/cm], SF6에서 80∼90[kV/cm]으로 개선되지만, 스위치의 주 응용이 진공 또는 우주에서 사용되기 때문에 이러한 현상은 매우 심각한 문제이다. 페시베이션후 소자들은 진공과 기중에서 언페시베이션된 소자가 SF6내에서 얻을 수 있는 만큼의 높은 파괴값을 가졌다. 이러한 결과로 볼 때 페시베이션된 소자들이 매우 우수한 파괴값을 가진다는 것을 알 수 있다. 본 논문은 고전계 하에서 페시베이션 전·후 실리콘 파괴의 주 특성과 메커니즘에 대해 밝혔다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.33-37
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• 2006

Since 1993, the civil aviation community through RTCA (Radio Technical Commission for Aeronautics) and the ICAO (International Civil Air Navigation Organization) have been working on the definition of GNSS augmentation systems that will provide improved levels of accuracy and integrity. These augmentation systems have been classified into three distinct groups: Aircraft Based Augmentation Systems (ABAS), Space Based Augmentation Systems (SBAS) and Ground Based Augmentation Systems (GBAS). The last one is an implemented system to support Air Navigation in CAT-I approaching operation. It consists of three primary subsystems: the GNSS Satellite subsystem that produces the ranging signals and navigation messages; the GBAS ground subsystem, which uses two or more GNSS receivers. It collects pseudo ranges for all GNSS satellites in view and computes and broadcasts differential corrections and integrity-related information; the Aircraft subsystem. Within the area of coverage of the ground station, aircraft subsystems may use the broadcast corrections to compute their own measurements in line with the differential principle. After selection of the desired FAS for the landing runway, the differentially corrected position is used to generate navigation guidance signals. Those are lateral and vertical deviations as well as distance to the threshold crossing point of the selected FAS and integrity flags. The Department of Applied Science in Naples has create for its study a virtual GBAS Ground station. Starting from three GPS double frequency receivers, we collect data of 24h measures session and in post processing we generate the GC (GBAS Correction). For this goal we use the software Pegasus V4.1 developed from EUROCONTROL. Generating the GC we have the possibility to study and monitor GBAS performance and integrity starting from a virtual functional architecture. The latter allows us to collect data without the necessity to found us authorization for the access to restricted area in airport where there is one GBAS installation.

• Journal of Chest Surgery
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• 제31권5호
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• pp.513-517
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• 1998

비디오 흉강경의 이용은 여러 흉부질환에서 개흉술을 대치해 나가는 경향이며, 오늘날 광범위한 적응증은 개흉술의 대치가 보다 안전하고 유용함을 보여준다. 본원에서는 1993년 6월부터 1995년 6월까지 비디오 흉강경을 이용해 치료한 33명의 환자를 대상으로 하였다. 이들의 진단명을 보면 재발성 기흉이 16례, 엑스레이상 기포가 보이는 경우가 6례, 7일 이상 공기유출이 지속되는 경우가 4례, 양측성 기흉이 3례, 다한증 2례, 반대측 기흉의 과거력이 1례, 원발성 혈기흉 1례 순이었다. 이들의 평균 흉관 삽관 기간은 2.1$\pm$0.4일 이었으며, 재원 기간은 3.4$\pm$0.6일 이었으며 합병증은 48시간이상 자속된 공기유출이 3례에서 있었다. 이상과 같이 비디오 흉강경을 이용한 흉부 수술은 안전하고, 통증이 적으며, 짧은 재원 기간을 보여준다.

• Journal of Chest Surgery
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• 제2권2호
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• pp.147-154
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• 1969

This is a report on a total of 11 cases of esophageal perforation in the department of thoracic surgery, Chonnam University Hospital during the period of 8 years from 1962 to 1969. They occurred by the following agents, that is,lye solution[7 cases], fish bone[2 cases]. compress air [one case], strong acid [one case]. The perforated portions of esophagus were cervical esophagus in 2 cases, upper third of esophagus in 5 cases, middle third of esophagus in 3 cases and lower third of esophagus [abdominal esophagus] in one case. 4 cases out of cases of esophageal perforation after ingestion of Lye solution were due to Bougination to improve esophageal stenosis: 2 cases occurred 2 months after ingestion of Lye solution and the remaining 2 cases, 2 to 3 weeks after Lye solution ingestion. Therefore, It is realized that Bougination for esephageal stricture by Lye solution is particularly dangerous. The complication after esophageal perforation were mediastinitis,[10 cases], right pyothorax with mediastinitis [8 cases], peritonitis [4 cases], esophago-bronchial fistula[one case]. Owing to the various complications above mentioned, surgical approach to esophageal perforation is accordingly complicated and a combination of more than two of the following different procedures were properly used case by case, that is. gastrostomy or jejunostomy for feeding and esophageal rest,thoracotomy and chest drainage, lung decortication for pyothorax, primary closure of compress air perforation and esophago-bronchial fistula, mediastinostomy, retrosternal esophagoplasty using right colon to Lye stricture etc. 5 cases[45. 5%] of 11 cases were expired and the rest of 6 cases[54.5%]were survived with complete accomplishment of surgical procedures and satisfactory healing in 4 cases and interruption of follow up in 2 cases because of poor economical condition of the patients.

• 상하수도학회지
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• 제33권4호
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• pp.243-250
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• 2019

This objective of this study was to investigate the degradation characteristics of phenol, a refractory substance, by using a submerged dielectric barrier discharge (DBD) plasma reactor. To indirectly determine the concentration of active species produced in the DBD plasma, the dissolved ozone was measured. To investigate the phenol degradation characteristics, the phenol and chemical oxygen demand (COD) concentrations were evaluated based on pH and the discharge power. The dissolved ozone was measured based on the air flow rate and power discharged. The highest dissolved ozone concentration was recorded when the injected air flow rate was 5 L/min. At a discharge power of 40W as compared to 70W, the dissolved ozone was approximately 2.7 - 6.5 times higher. In regards to phenol degradation, the final degradation rate was highest at about 74.06%, when the initial pH was 10. At a discharged power of 40W, the rate of phenol decomposition was observed to be approximately 1.25 times higher compared to when the discharged power was 70W. It was established that the phenol degradation reaction was a primary reaction, and when the discharge power was 40W as opposed to 70W, the reaction rate constant(k) was approximately 1.72 times higher.

• 한국농촌건축학회논문집
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• 제21권3호
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• pp.17-24
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• 2019

This study aimed to develop a mobile separating and sorting device for discharge sites to separate and sort mixed construction waste generated in small and medium scale in small provincial cities into inorganic materials and combustible materials. The study results can be summarized as follows: 1) As a result of analyzing the existing domestic technology for the separating and sorting mixed construction waste, a device sorting the waste by fusing the vibration screen, disc screen, air blowing methods and the separating and sorting the combustible waste is applied in Korea. 2) In foreign countries, the air blowing, screen, gravity sorters are used for separating and sorting combustible waste in the same way as in Korea. Especially German T Company suggests a construction waste separating and sorting system using an optical sorter. 3) As for the test device for separating and sorting mixed construction waste to be buried in landfill, the processing capacity was set as 16 tons per day. 4) For separating and sorting inorganic materials by granularity, this study set a trommel with two types of diameter as a basic. To operate the mobile all-in-one system, the device is designed to locate a conveyor, a combustible waste conveying device, inside of the trommel. 5) The device is designed in a mobile mode under the concept of primary separating and sorting device, and it can be transported using a 2.5-ton truck minimum. The diameter and length of the trommel are designed to be within 1500mm and 3000mm, respectively. In a further study, an optimized separating and sorting technology is planned to be presented through an experimental study for processing efficiency analysis at the mixed construction waste site by manufacturing the pilot experiment facility reflecting the design elements in the result of this study.

• 한국수산과학회지
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• 제51권6호
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• pp.632-639
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• 2018

To develop the high-value added seafood products from a regional speciality seafood, the seasoned dried pen shell Atrina pectinata adductor (SDPA) and seasoned smoke-dried pen shell adductor (SSPA) samples were prepared, and their optimal processing conditions, quality metrics, and shelf-life characteristics were examined. SDPA and SSPA samples were produced by thawing of frozen pen shell adductor, and cutting it into 6-7 mm slices, hot-air drying ($60^{\circ}C$, 20 min) or smoking ($110^{\circ}C$, 20 min), seasoning ($4^{\circ}C$, 12 h) with seasoning powder (60% sorbitol, 15% sucrose, 16% salt and 9.0% monosodium glutamate), hot-air drying ($60^{\circ}C$, 3 h), torching, vacuum-packaging in a laminated plastic film bag, heat treating with hot-water ($85^{\circ}C$, 15 min), and cooling. The moisture content of SDPA and SSPA samples was 44.5 and 43.0%, respectively, and the water activity was 0.845 and 0.842. The total amino acids in SDPA and SSPA samples were 20,986.8 and 21,312.4 mg/100 g, respectively, and the major amino acids in both products were aspartic acid, serine, glutamic acid, proline, glycine, alanine, valine, leucine, phenylalanine, lysine and arginine. The primary minerals were Na, S, K and P. Incubating tests indicated that the quality of SDPA and SSPA samples was maintained for 30 days of storage.