• 한국수소및신에너지학회논문집
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• 제21권6호
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• pp.507-512
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• 2010

The effect of catholyte to anolyte amount ratio on the electrodialysis cell performance for HI concentration was investigated. For this purpose, the electrodialysis cell was assembled with Nafion 117 as PEM membrane and activated carbon fiber cloth as electrodes. The initial amount of catholyte was 310 g and that of anolyte varied from 1 to 3 of amount ratio. The calculated electro motive force (EMF) increased with time and the increment enhanced as the amount ratio of catholyte to anolyte decreased. The mole ratios of HI to $H_2O$ (HI molarity) in catholyte were almost the same and exceeded pseudo-azeotropic composition for all amount ratios after 2 h operation. The HI molarity continuously increased with time for 10 h operation. The mole ratio of $I_2$ to HI decreased in catholyte but increased in anolyte. The increment of mole ratio of $I_2$ to HI in anolyte rose as the amount ratio of catholyte to anolyte decreased. In case of 1:1 amount ratio, the cell operation was stopped for the safety at approximately 6 h operation, since the mole ratio of $I_2$ to HI reached solubility limit. The cell voltage of the electrodialysis cell increased with time and the rate of increase was high at low amount ratio. This suggests that the amount ratio of catholyte to anolyte not only crucially influences the cell voltage, but also cell operation condition.

• 한국해안해양공학회지
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• 제11권4호
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• pp.216-230
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• 1999

확장형 완경사방정식을 지배방정식으로 사용하며 무한원방에서의 방사조건은 무한요소로, 그리고 항입구에서의 흐름분리로 인한 에너지 손실의 고려는 정합요소로 처리하는 Galerkin 유한요소 모형을 개발하였다. 완전 및 부분 개방 직사각형 항만에 대한 수치실험 결과 항입구에서의 에너지 손실의 포함은 港奧에서의 증폭비를 상당히 감소시키는 것으로 나타났으며, 입사파고와 제트 길이의 증가는 증폭비의 상당한 감소를 초래하였다. 감천항에서 제트길이를 고려한 경우 공진주기의 이동으로 입사파 진폭이 작을 때는 손실을 고려하지 않은 경우보다 진폭비가 오히려 크게 나타났다. 관측된 입사 장주기 파고의 사용시에는 항입구 손실이 작은 것으로 나타났으나 지진해일의 내습시와 같이 파고가 큰 경우에는 상당한 입구 손실이 예상되었다. 감천항의 Helmholtz 공진모드는 주기 31.0분으로 제시되어 관측 겨로가인 27.0~33.3분과 잘 일치하였다. 또한 관측치인 주기 9.4~12.1분과 5.2~6.2분의 공진모드도 10.4분과 6.6분 또는 5.6분으로 상당히 재현되었다. 한편, 감천항에는 매우 다양한 모드의 부진동이 존재하는 것으로 나타났으며, 영일만 마찬가지로 주기 3.6분과 1.6분에서 상당한 진폭비의 횡방향 공진이 존재함을 확인하였다.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1532-1536
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• 2020

For ensuring nuclear safeguards, we report the analytical signal-detection performance of thermal ionization mass spectrometry (TIMS) with continuous heating for the measurement of isotopic ratios in samples containing ultra-trace amounts of uranium. As methods for detecting uranium signals, peak-jumping mode using a single detector and static mode using multiple detectors were examined with U100 (10% ²³⁵U-enriched) uranium standard samples in the femtogram-to-picogram range. Uranium isotope ratios, n(²³⁵U)/n(²³⁸U), were measured down to levels of 1 fg and 3 fg in static and peak-jumping modes, respectively, while n(²³⁴U)/n(²³⁸U) and n(²³⁶U)/n(²³⁸U) values were measured down to levels of 100 fg in both modes. In addition, the dependency of the ²³⁸U signal intensity on sample quantity exhibited similar tendencies in both modes. The precisions of the isotope ratios obtained in the static mode over all sample ranges used in this study were overall slightly higher than those obtained in peak-jumping mode. These results indicate that isotope ratio measurements by TIMS with continuous heating are almost independent of the detection method, i.e., peak-jumping mode or static mode, which is characteristic of isotope-ratio measurements using the TIMS method with continuous heating. TIMS with continuous heating is advantageous as it exhibits the properties of multiple detectors within a single detector, and is expected to be used in various fields in addition to ensuring nuclear safeguards.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.154-157
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• 2011

Hydrogenated silicon nitride deposited by LF-PECVD is commonly used for anti-reflection coating and passivation in silicon solar cell fabrication. The deposition of the optimized silicon nitride on the surface is elemental in crystalline silicon solar cell. In this work, the carrier lifetimes were measured while the thicknesses of $SiN_x$ were changed from 700 ${\AA}$ to 1150 ${\AA}$ with the gas flow of $SiH_4$ as 40 sccm and $NH_3$ as 120 sccm,. The carrier lifetime enhanced as the thickness of $SiN_x$ increased due to improved passivation effect. To study the characteristics of $SiN_x$ with various gas ratios, the gas flow of $NH_3$ was changed from 40 sccm to 200 sccm with intervals of 40 sccm. The thickness of $SiN_x$ was fixed as 1000 ${\AA}$ and the gas flow of $SiH_4$ as 40 sccm. The refractive index of SiNx and the carrier lifetime were measured before and after heat treating at $650^{\circ}C$ to investigate their change by the firing process in solar cell fabrication. The index of refraction of SiNx decreased as the gas ratios increased and the longest carrier lifetime was measured with the gas ratio $NH_3/SiH_4$ of 3.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.121-128
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• 2005

In this study the influences of ground motion characteristics and structural properties on energy demands were evaluated using 100 earthquake ground motions recorded in different soil conditions, and the results were compared with those of previous works. Results show that ductility ratios and the site conditions have significant influence on input energy. The ratio of hysteretic to input energy is considerably influenced by the ductility ratio and damping ratio, while site condition has minor effects.

• 한국식품영양과학회지
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• 제12권2호
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• pp.73-83
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• 1983

단백질(蛋白質)의 상호보충(相互補充) 및 제한(制限)아미노산 보충(補充)이 흰쥐(Sprague Dawley계(系) 이유(離乳)한 숫쥐)의 성장(成長), 체내대사(體內代謝) 및 체조성(體組成)에 미치는 영향(影響)을 규명하기 위하여 사양(飼養) 및 대사실험(代謝實驗)을 실시(實施)하였다. 실험사료(實驗飼料)의 에너지 및 단백질(蛋白質) 수준(水準)은 각각 3,600kcal/㎏ 및 20%로 고정하였고, 단백질(蛋白質)의 공급원(供給源)으로 카제인과 대두단백질(大豆蛋白質)을 택(擇)하여 각각 100:0, 80:20, 50:50, 20:80, 0:100의 비율(比率)로 혼합(混合)하였으며 각각에 methionine을 0% 또는 0.3%로 보충(補充)하였던 결과를 요약(要約)하면 다음과 같다. 흰쥐의 체중(體重)과 증체량(增體量)은 대두단백질(大豆蛋白質) 단독(單獨) 급여(給與) 때 가장 낮았고 카제인의 혼합비율(混合比率)을 증가(增加)시킬 수록 증가(增加)되었다. 대두단백질(大豆蛋白質)에 methionine을 보충급여(補充給與)했을 때 증체량(增體量)은 무보충(無補充) 혼합(混合) 급여(給與)했을 때와 동일(同一)했으며 카제인 단독(單獨) 급여(給與)때 보다 카제인 혼합(混合) methionine 보충(補充) 급여(給與)에서 증체량(增體量)은 더 높았다. 사료섭취량(飼料攝取量)은 카제인 단독급여(單獨給與) 때나 카제인의 혼합비율(混合比率)을 증가(增加)시킬 때 높았으나 meihionine을 보충(補充)했을 때 저하(低下)되었으며 대두단백질(大豆蛋白質) 단독급여(單獨給與)에서 낮았으며 methionine을 보충(補充)해도 증가(增加)되지 않았다. 사료효율(飼料效率)은 카제인이나 대두단백질(大豆蛋白質)의 단독(單獨) 급여(給與)때보다 두 단백질(蛋白質)의 혼합급여(混合給與) 때 더 높았으며 단독급여(單獨給與)에 methionine을 보충(補充)함으로써 사료효율(飼料效率)이 증가(增加)되었으나 혼합급여(混合給與)에 보충(補充)했을 때에는 같은 효과(效果)를 보이지 않았다. 성장실험기간중(成長實驗期間中) 총(總)에너지섭취량(攝取量)은 사료(飼料) 섭취량(攝取量)과 관계가 있었고 카제인 단독급여(單獨給與) 때나 그의 혼합비율(混合比率)을 증가(增加)시킬 때 증가(增加)했다. 에너지효율(效率)과 단백질효율(蛋白質效率)은 두 단백질(蛋白質)을 단독급여(單獨給與)할 때에는 methionine보충(補充)에 의해 증가(增加) 되었으며 또한 혼합급여(混合給與) 때에는 대두단백질(大豆蛋白質)의 비율(比率)을 증가(增加)시킬 수록 methionine에 의한 개선효과(改善效果)를 보였다. 질소섭취량(窒素攝取量) 및 카제인 뇨질소량(尿窒素量)은 단독급여(單獨給與) 했을 때 가장 높았고, 대두단백질(大豆蛋白質) 단독급여(單獨給與) 때 가장 낮았으며 카제인의 비율(比率)을 증가(增加)시킬 수로 증가(增加)되었다. 질소균형(窒素均衡) 및 축적율(蓄積率)은 처리(處理)에 의한 차이(差異)에 통계적(統計的) 유의성(有意性)은 없었다. 대사실험기간중(代謝實驗期間中) 총(總)에너지섭취량(攝取量)과 분(糞) 및 뇨(尿)에너지는 카제인 단독급여(單獨給與) 때 높았고, 가소화(可消化) 에너지와 대사(代謝)에너지, 에너지의 소화율(消化率) 및 리용율(利用率)은 처리(處理)에 의한 유의차(有意差)는 없었다. 체지방(體脂肪)은 methionine보충(補充)에 의해 증가(增加)되었으나, 체단백질(體蛋白質)은 감소(減少)했다(r=0.65, p<0.01). 체지방(體脂肪)과 체수분(體水分)과도 부(負)의 상관관계(相關關係)(r=-0.83, p<0.01)가 있었다. 간(肝)의 무게는 도체(屠體)의 무게의 변화(變化)와 일치(一致)했고 (r=0.79, p<0.01) methionine보충(補充)에 의해 증가(增加) 되었으며 카제인의 비율(比率)을 증가(增加)시킬 수록 증가(增加)되었다.

• KIEAE Journal
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• 제15권1호
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• pp.155-160
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• 2015

The annual average of energy sources is continuously increasing at a rate of 5.8%, and particularly, the power generation proportion of new/renewable energy is increasing significantly. Furthermore, South Korea has established a national energy master plan for 2008-2030 and is aiming at obtaining approximately 11% of total energy production from the wind turbine sector. Although offshore wind turbines are similar to wind turbines installed on land, they require materials with excellent dynamic properties and durability to prevent damage due to seawater at the lower parts and connecting parts. The lower parts of wind turbines are submerged in seawater, and the upper and lower parts are connected by filling the connecting part with grout. This paper describes the test results of the process of determining the mix ratios to develop ultra-high grout for offshore wind turbines. There is virtually no relevant technology regarding grout for offshore wind turbines in South Korea that can be referenced for the process of determining the mix ratios. Therefore, tests were conducted for determining compression strength, elastic modulus, flexural strength, density, constructability (floor test), and early strength by referencing a high-performance grout produced in South Korea, and the mixing process for achieving the goal strengths was described using the Korean Industrial Standards (KS) as the reference.

• 대한핵의학회지
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• 제15권1호
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• pp.13-20
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• 1981

Using stannous chloride, optimum conditions for $^{99m}Tc$ labelling of some scanning agents such as phytic acid (P A), dimercaptosuccinic acid (DMSA), and calcium diethylenetriaminepentaacetate (Ca-DPTA) were established. Methods of separation and identification of the labelled compounds were practiced by a paper- or thin layer- chromatography. Biodynamic studies of the compounds were also carried out. The results indicate that the molar ratios of the chelating agent and stannous chloride varies only with the concentrations of the chelating agents, and thus the amounts of the stannous chloride per labelling tube were nearly constant $(500\sim600{\mu}g)$ regardless the variation of the molar ratios. It suggests that the given experimental conditions require about $500{\mu}g$ of stannous chloride regardless of the chelating agents. Under alkaline pH, the labelling yields were drastically decreased due to the probable formation of colloidal tin compounds. Biodynamic data showed characteristic patterns with each compound indicating that they are all suitable for the relevant scanning applications.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4159-4166
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• 2023

Laser decontamination of radioactive surfaces is an innovative technology. Our contribution to improving this technology includes studies on laser beam decontamination with a pulsed laser of an average power of 150 W, equipped with a hand guided working head. Our investigations are focused on metallic surfaces typical in nuclear power plants, such as stainless steel, bright and rusted mild steel, galvanized steel, and painted steel. As typical nuclides of contaminated surfaces we chose Co-60 and Cs-137, the most frequently occurring nuclides in many nuclear plant components; Sr-85 as a representative of Sr-90, the potentially most harmful fission nuclide; and Am-241 as a representative of the minor alpha-radiation emitting actinides. Here, we present our results of decontamination and recovery ratios. Decontamination ratios of 90-100% were achieved on different surfaces.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.585-588
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• 2001

Particle contamination on the data storage disks has been a serious problem for magnetic hard disk drive manufacturers. For high storage optical disks, such as DVD-ROM/RAM or NFR (near field recording) system, particle-induced damages can be also detected because only a few micrometer particles can prevent read/write signal from optical lens. The increasing areal density and smaller bit size accelerates particle induced damages on the optical disk. One of the methods to prevent particle contamination on the optical disk surface is to handle the disk enclosed in a cartridge like a modern DVD-RAM disk. However, even for a perfectly sealed disk drive, particles are found inside the drive. The other method is to improve disk surface characteristics. Particle contamination on the surface can be reduced by proper selection of disk coating materials. [n this paper, particle detachment ratios for CD (compact disk), DVD (digital versatile disk), HD (magnetic hard disk), HD with Jut lubricant, and aluminosilicate substrate HD were investigated. Surface roughness and surface energy of the test disks were compared with the particle detachment ratios. Proper substrate and lubricant characteristics to reduce particle contamination on the disk surface were found.