Fracture Behavior of Locally Corroded Steel Pipeline in District Heating System Using the Combination of Electrochemistry and Fracture Mechanics

Seon‑Hong Kim,Yoon‑Sik So,Jung‑Gu Kim 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.11

To identify the effects of the stress concentration at the pit on the fracture of the district heating (DH) pipeline, the stressincrease with the wall thickness reduction was formulated. The formula includes the stress intensity factor with the pittingcorrosion. As a result of the application of the DH pipeline conditions to the ASME B31.3 code formula and corrosion test,the interplay with only uniform corrosion and stress due to the internal pressure can not be an immediate reason for the DHpipeline fracture. The KIvalue which is calculated by loss of thickness due to both uniform and localized corrosion exceededfracture toughness value (42 MPa√m) of the weldment pipeline steel (ASTM A106 Gr. B) under all of the studied conditions.

Proteomic Approach to Analyzing Flooding Stress in Soybean (Glycine max(L.) Merr.)

Kim,Tae-Seon,Cho,Seong-Woo,Lee,Jae-Eun,Kim,Yook-Han,Cho,Kun,Choi,Jong-Soon,Chung,Keun-Yook,Song,Beom-Heon,Jong,Seung-Keun,Kim,Hong-Sig,Woo,Sun-Hee 한국작물학회 2005 한국작물학회 학술발표대회 논문집 Vol.2005 No.-

폐결핵 환자의 우울 상태

홍정표,최선희,조만종,이성주,박종,김기순,김양옥 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.1

The main purpose of this study is to identify and evaluate the depressive states for the patients with chronic pulmonary tuberculosis. A questionnaire(Self-rating Depression Scale, SDS) survey was performed toward 57 pulmonary tuberculosis patients with initial treatment who started chemotherapy and 53 pulmonary tuberculosis patients with retreatment, admitted to one tuberculosis-centered hospital and two general hospital. Fifty three healthy persons as control group were investigated with the same questionnaire for comparison. The survey was performed from July to August 1996. The results are as follws : 1. The patients had significantly high scores in the depression than control and the patient with retreatment showed significantly high scores in the depression than the patient with initia1treatment(P<0.01). 2. The depressive levels of the patients were associated with duration of admission and the expectancy of recovery (P<0.05). 3. The percentage of the subjects with 40 or more scores tentatively classifiable as psychologically depressed was 67.1% of the total subjects, 48.4% of the control groups, 75.0% of the patient with initial treatment and 84.1% of the patient with retreatment. Because patient with pulmonary tuberculosis with initial treatment showed higher depression scores than normal persons, and patients with retreatment due to failure of initial treatment showed higher depression scores than initial treatment, it is necessary to give attention to depression of the patients during treatment of pulmonary tuberculosis.

GC/NPD를 이용한 다성분 잔류농약의 동시분석

김우성,이선화,김상엽,정동윤,김재이,이영자,이홍재,정성욱,박흥재 한국환경과학회 2003 한국환경과학회지 Vol.12 No.10

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with fiorisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD, Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.

제주도 한라산 1100 고지 대기 에어로졸의 조성 및 특성

김원형,강창희,신찬성,고선영,홍민선 濟州大學校 基礎科學硏究所 2003 基礎科學硏究 Vol.16 No.1

The atmospheric aerosols collected at the 1100 site located in Mt. Halla have been analyzed to investigate their compositions and chemical characteristics. The average concentrations of water-soluble cautions were in the order of NH_(4)^(+)>Ca^(2+)>Na^(+)>K^(+)>Mg^(2+) during the spring, showing high increase of Ca^(2+) concentration with the value of 0.60㎍/㎥, and NH_(4)^(+)>Na^(+)>K^(+)>Ca^(2+)>Mg^(2+) during the other seasons. The average concentrations of anions have shown in the order of SO_(4)^(2-)>NO_(3)^(-)>Cl^(-) for all seasons, and SO_(4)^(2-) and NO_(3)^(-) had higher concentrations in spring with the values of 4.84㎍/㎥ and 1.08㎍/㎥, respectively. From the analytical data of size-segregated particles by cascade impactor sampling, the components of NH_(4)^(+), SO_(4)^(2-), NO_(3)^(-) and K^(+) were distributed mainly in fine particles, but Ca^(2+), Na^(+), Mg^(2+) and Cl^(-) were included mostly in coarse particles. The correlation coefficients of nss-SO_(4)^(2-)/NH_(4)^(+), nss-SO_(4)^(2-)/K^(+) and NO_(3)/nss-Ca^(2+) showed quite high values with 0.871, 0.857 and 0.654, respectively. Based on the study of enrichment factors, it is considered that Na^(+), Mg^(2+), Cl^(-) and Ca^(2+) components were delivered from oceanic and soil sources, but SO_(4)^(2-), NO_(3)^(-) and NH_(4)^(+) might have other source origins. The factor analysis study showed the aerosol at the 1100 site was influenced mainly by anthropogenic factors, followed by oceanic and soil factors.

난각을 이용한 폐수중의 인 제거에 관한 연구

김민수,강선홍 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2

This study is a fundamental research to test the applicability of abandoned eggshell as seed material for crystallization reaction. Eggshell was calcinated at 850℃ and ground to lesser than 0.42㎜. The calcination characteristics of eggshell were examined by X-ray diffraction (XRD). The effect of initial calcium concentration, alkalinity, reaction temperature condition, seed dosage were studied by batch test. For the low concentration sample(P concentration is under 50㎎/L), more than 90% of P can be removed. The effect of initial calcium concentration(0-120㎎/L) was performed. At the result of the test, more than 50㎎/L calcium concentration has high removal efficiency. Alkalinity effect was studied for synthetic soIution(100㎎/L initial P, 50㎎/L calcium, 0.025% seed dosage) with 0∼300㎎/L bicarbonate alkalinities. For synthetic solution(100㎎/L initial P, 50㎎/L calcium, 100㎎/L bicarbonate alkalinity, 0.025% seed dosage), the phosphorus concentration was examined with 10-35℃. In addition, calcinated eggshell was injected to swine wastewater to test the applicability to actual wastewater.

셋트 제품의 컨테이너 적재 알고리즘 개발에 관한 연구

김홍배,노재정,강주선 慶星大學校 1998 論文集 Vol.19 No.1

This study is focused on the methodology for the determination of the loading pattern for set products which can be charactertized by the fact that various kinds of parts should be provided together in order to function as one product such as home appliances or military supplies. This study is composed of the development of the mathematical model and its solution algorithm. The model tries to maximize the utilization rate of the loading space under the condition that the same number of the components of each set product should be loaded. This study can give the loading pattern and present the quantity information on the sub-set products to the user. The result of this study is compared with George & Robinson's algorithm under the same condition that this study is performed.

만성중이염의 골도청력변화

박선홍,노용훈,이도용,나한조,김용기,최봉남,도남용 朝鮮大學校 附設 醫學硏究所 1996 The Medical Journal of Chosun University Vol.21 No.1

We have usually experienced bone conduction impairment in chronic otitis media, but it is unclear that raised bone conduction threshold is due to the reflection of cochlear dam- age and / or Carhart effect ( an artificial elevation of bone conduction threshold due to conductive defect ) or both. The purpose of this study is to verify the influence of the artificial elevation of the bone conduction threshold in chronic otitis media and to estimate Carhart effect. A total of 336 cases of tympanoplasty with unilateral chronic otitis media without any other causes of sensorineural hearing loss was studied. The average threshold levels of the bone conduction in diseased ears ranged from 18.5dB at 4kHz to 12.1dB at 250Hz The longer duration of the disease, the larger perforation size, the more severe damage of the middle ear structure and the presence of the cholesteatoma made bone conduction threshold increased. The postoperative thresholds of bone conduction were Improved in 36 cases (40.4%) of the 89 cases that underwent operation with type I tympanoplasty technique without electrie drilling. The degree of the maximal improvement was 14.3dB at 2000Hz and the minimum was 8.8dB at 250Hz. but these result did differ from a statistically significant degree. The result suggest that the bone conduction threshold in chronic otitis media is elevated artificially by conductive defect and improved by successful reconstructive surgery.

남자 대학생에서 걷기와 달리기 운동 시 체지방과 골격근량에 대한 비교

김아름,강지선,노홍서,오지훈,강현주 순천향대학교 기초과학연구소 2021 순천향자연과학연구 논문집 Vol.27 No.1.2

The purpose of this study was to investigate the difference in body fat mass and skeletal muscle mass during walking and running after resistance training based on healthy college student. One male college student (age = 25 years, Height = 175.0 cm, Weight = 86.9 kg, Body fat = 27%) volunteered to participate in the study. Body composition was assessed by bioelectrical impedance (Inbody 270, Korea). Walking exercise (4.8 km/hr, 60 min) was performed for 3 weeks, followed by running exercise (7.0 km/hr, 26 min) for 3 weeks. The experimental results are as follows. Running was more effective at dropping body weight and BMI than walking, however walking was more effective at reducing body fat (%) and increasing skeletal muscle mass (kg) than running in male college student. In conclusion, both walking and running provide benefits for body composition, and the best exercise for weight and body fat loss is the one that it actually do on a regular basis.

Base Emitter Codiffusion 소자 제조 및 전기적 특성 고찰

李善東,金政彦,朴淳太,梁光鎭,洪昌熹 동아대학교 공과대학 부설 한국자원개발연구소 1990 硏究報告 Vol.14 No.2

In the time when we fabricated the NPH bipolar transistor the temperature annealing was needed. Then the properties of transistor was damaged because of inducing the silicon lattice defects. In this paper, proposed codiffusion method was able to control of junction depth by implant energy, dose concentration, diffusing temperature and annealing time control. In addition to, we studied for developed the transistor of high speed switching.