• Animal Bioscience
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• 제35권5호
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• pp.721-729
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• 2022

Objective: An experiment was conducted to determine the effects of supplementing graded concentrations of inorganic sulphur (S) without and with folic acid (FA) in maize-soybean meal diets on performance, slaughter and anti-oxidant variables, immune responses and serum protein fractions in broiler chicken. Methods: Inorganic S was supplemented at 0.05%, 0.10%, 0.15%, and 0.20% alone or in combination with FA (4 mg/kg) in basal diet (BD) containing no supplemental methionine (Met) and FA. A control group was fed with the recommended concentration of Met. Each diet was offered to 10 pens of 5 male broiler chicks (Cobb 400) and fed ad libitum from day 1 to 42. Results: The broilers fed the BD had lower body weight gain (BWG), feed efficiency (FE), higher lipid peroxidation (LP), lower activity of glutathione peroxidase (GSHPx), lower lymphocyte proliferation ratio (LPR), and reduced concentrations of total protein, albumin, and globulin in serum. Supplementation of FA and S to the BD improved the BWG (all concentrations of S) and FE (0.20% S) similar to the control group. Similarly, the combination of S and FA significantly improved the concentrations of total protein, albumin, and globulin in serum, reduced the LP and increased the activity of GSHPx and LPR. However, responses in the above parameters were related to the concentration of S in the diet. The slaughter variables and antibody titres against the Newcastle disease were not affected with the treatments. Conclusion: Based on the results, it is concluded that the combination of S (0.2%) and FA (4 mg/kg) improved the BWG and FE, similarly supplementation of these nutrients improved the concentration of protein fractions and reduced the stress (reduced LP and improved GSHPx) variables in serum and improved the cell mediated immune response (LPR) in broilers fed sub-optimal concentrations of Met in diet.

• 한국입자에어로졸학회지
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• 제18권3호
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• pp.69-77
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• 2022

In order to understand the characteristics of fine particles emitted from coal-fired power plant stacks, it is important to analyze the size distribution and components of particles. In this study, particle size distributions were measured using the ejector-porous tube dilution device and an ELPI system at a stack in a coal-fired power plant. Main elemental components of particles in each size interval were also identified through TEM-EDS analysis for the particles collected in each ELPI stage. Particle size distributions based on number and mass were analyzed with component distributions from 0.006 to 10 ㎛. The highest number concentration was about 0.01 ㎛. The main component of the particles consisted of sulfur, which indicated that sulfate aerosols were generated by gas-to-particle conversion of SO2. In a mass size distribution, a mono-modal distribution with a mode diameter of about 2 ㎛ was shown. For the components of PM1.0 (particles less than 1 ㎛), the abundance order was F > Mg > S > Ca, and however, for the components of PM10 (particles less than 10 ㎛), it was in the order of Fe > S > Ca > Mg. The elemental components by particle size were confirmed.

• Current Photovoltaic Research
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• 제11권3호
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• pp.67-74
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• 2023

The earth-abundant element-based Cu₂ZnSn(S,Se)₄ (CZTSSe) thin film solar cells (TFSCs) have attracted greater attention in the photovoltaic (PV) community due to their rapid development in device power conversion efficiency (PCE) >13%. In the present work, we demonstrated the fine-tuning of the bandgap in the CZTSSe TFSCs by altering the sulfur (S) to the selenium (Se) chalcogenide ratio. To achieve this, the CZTSSe absorber layers are fabricated with different S/(S+Se) ratios from 0.02 to 0.08 of their weight percentage. Further compositional, morphological, and optoelectronic properties are studied using various characterization techniques. It is observed that the change in the S/(S+Se) ratios has minimal impact on the overall Cu/(Zn+Sn) composition ratio. In contrast, the S and Se content within the CZTSSe absorber layer gets altered with a change in the S/(S+Se) ratio. It also influences the overall absorber quality and gets worse at higher S/(S+Se). Furthermore, the device performance evaluated for similar CZTSSe TFSCs showed a linear increase and decrease in the open circuit voltage (V_oc) and short circuit current density (J_sc) of the device with an increasing S/(S+Se) ratio. The external quantum efficiency (EQE) measured also exhibited a linear blue shift in absorption edge, increasing the bandgap from 1.056 eV to 1.228 eV, respectively.

• 대한조선학회논문집
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• 제60권4호
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• pp.213-221
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• 2023

The demand for Liquefied Natural Gas (LNG) carriers and LNG-fueled ships has significantly increased in recent years due to the sulfur-oxide emission regulations by the International Maritime Organization (IMO). The main goal of this paper is to introduce the process for the Engineering Critical Assessment (ECA) of IMO independent type-B cargo tanks made from 9% nickel alloy. A methodology proposed by the British Standard was used to conduct ECA for any structure with initial flaws. Based on this standard, a Matlab code was developed to perform ECA. Coarse mesh Finite Element Analysis (FEA) was performed on an independent type-B LNG cargo tank with a capacity of 15,000 m³. The location with the highest development of maximum principal stress was identified at the bottom of the cargo tank. Fine mesh FEA was performed to obtain the stress range required for ECA. The dynamic cargo tank loads used for FEA were determined using some ship rules presented by Det Norske Veritas. As a result of performing a 20-year long-term crack propagation analysis with a semi-elliptical surface crack, the fracture-to-yield ratio exceeded the Fracture Assessment Line (FAL) and some structural reinforcement was necessary. Performing a 15-day short-term crack propagation analysis, the fracture-to-yield ratio remained within the FAL, and no significant LNG leaks were expected. This paper is believed to provide a guide for performing ECA of LNG cargo tanks in the future by providing the basic theory and application sample necessary to perform ECA.

• 한국환경보건학회지
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• 제49권3호
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• pp.149-158
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• 2023

Background: Injury is one of the major health problems in South Korea. Few studies have evaluated both intentional and unintentional injury when investigating the association between exposure to air pollutants and injury. Objectives: We aimed to explore the association between short-term exposure to ambient air pollution and years of life lost (YLLs) due to injury. Methods: Data on daily YLLs for 2002~2019 were obtained from the the Death Statistics Database of the Korean National Statistical Office. This study estimated short-term exposure to particulate matter with an aerodynamic diameter of <10 ㎛ (PM₁₀), particulate matter with an aerodynamic diameter of <2.5 ㎛ (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). This time series study was conducted using a generalized additive model (GAM) assuming a Gaussian distribution. We also evaluated a delayed effect of ambient air pollution by constructing a lag structure up to seven days. The best-fitting lag was selected based on smallest generalized cross validation (GCV) value. To explore effect modification by intentionality of injury (i.e., intentional injury [self-harm, assault] and unintentional injury), we conducted stratified subgroup analyses. Additionally, we stratified unintentional injury by mechanism (traffic accident, fall, etc.). Results: During the study period, the average daily YLLs due to injury was 307.5 years. In the intentional injury, YLLs due to self-harm and assault showed positive association with air pollutants. In the unintentional injury, YLLs due to fall, electric current, fire and poisoning showed positive association with air pollutants, whereas YLLs due to traffic accident, mechanical force and drowning/submersion showed negative associations with air pollutants. Conclusions: Injury is recognized as preventable, and effective strategies to create a safe society are important. Therefore, we need to establish strategies to prevent injury and consider air pollutants in this regard.

• 한국식품영양학회지
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• 제36권6호
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• pp.572-580
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• 2023

Hypertension is characterized by excessive renin-angiotensin system activity, leading to blood vessel constriction. Several synthetic compounds have been developed to inhibit renin and angiotensin-converting enzyme (ACE). These drugs often have adverse side effects, driving the exploration of plant protein-derived peptides as alternative or supplementary treatments. This study assessed the phenolic compound and amino acid content and the antioxidant and antihypertensive activity of 5 South Korean staple crops. Sorghum had the highest phenolic compound content and exhibited the highest antioxidant activity. Millet grains, particularly finger millet (38.86%), showed higher antihypertensive activity than red beans (14.42%) and sorghum (17.16%). Finger millet was found to contain a large proportion of branched-chain, aromatic, and sulfur-containing amino acids, which are associated with ACE inhibition. In particular, cysteine content was positively correlated with ACE inhibition in the crops tested (r=0.696, p<0.01). This study confirmed that the amino acid composition was more correlated with the antihypertensive activity of grains than the phenolic compound content. Finger millet mainly contained amino acids, which have higher ACE inhibitory activity, resulting in the strongest antihypertensive activity. These findings underscore the antihypertensive potential of select crops as plant-based food ingredients, offering insight into their biological functions.

• Journal of Information Technology Applications and Management
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• 제30권1호
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• pp.1-9
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• 2023

Interest in the future of the battery market is growing as Tesla announces plans to increase production of electric vehicles and to produce batteries. Tesla announced an action plan to reduce battery prices by 56% through 'Battery Day', which included expansion of factories to internalize batteries and improvement of materials and production technology. In the trend of automobile electrification, the expansion of the battery market, which accounts for 40% of the cost of electric vehicles, is inevitable, and the size of the electric vehicle battery market in 2026 is expected to increase more than five times compared to 2016. With the development of materials and process technology, the energy density of electric vehicle batteries is increasing while the price is decreasing. Soon, electric vehicles and internal combustion locomotives are expected to compete on the same line. Recently, the mileage of electric vehicles is approaching that of an internal combustion locomotive due to the installation of high-capacity batteries. In the EV battery market, Korean, Chinese and Japanese companies are fiercely competing. Based on market share in the first half of 2020, LG Chem, CATL, and Panasonic are leading the EV battery supply, and the top 10 companies included 3 Korean companies, 5 Chinese companies, and 2 Japanese companies. All-solid, lithium-sulfur, sodium-ion, and lithium air batteries are being discussed as the next-generation batteries after lithium-ion, among which all-solid-state batteries are the most active. All-solid-state batteries can dramatically improve stability and charging speed by using a solid electrolyte, and are excellent in terms of technology readiness level (TRL) among various technology alternatives. In order to increase the competitiveness of the battery industry in the future, efforts to increase the productivity and economy of electric vehicle batteries are also required along with the development of next-generation battery technology.

• 유기물자원화
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• 제31권4호
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• pp.51-58
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• 2023

본 연구에서는 혐기성소화에서 황화합물의 영향을 평가하기 위하여 탈황 슬러지 및 하수슬러지(생슬러지)를 이용한 병합소화를 진행하였다. 실험은 500 mL duran bottle을 이용한 batch test의 형태로 수행되었으며, 원료의 혼합 비율은 COD/SO₄의 비율을 기준으로 선정하였다. 실험 결과, COD/SO₄ 20 이하의 혼합 비율에서 바이오가스 발생량 및 수율의 감소가 확인되었다. 특히 COD/SO₄ 10 이하에서는 식종슬러지에서 자체적으로 발생하는 바이오가스를 보정하기 위해 원료를 투입하지 않은 seed (283.5 mL)보다 낮은 수치를 나타내었다. 메탄 수율의 경우 COD/SO₄ 50의 0.396 m³ CH₄/kg VS에 비해 COD/SO₄ 20에서 0.135 m³ CH₄/kg VS로 급격하게 감소하는 경향을 보였다. 반면, 황화수소의 수율은 COD/SO₄ 50의 0.0097 m³ H₂S/kg VS에 비해 COD/SO₄ 20의 비율에서 0.0223 m³ H₂S/kg VS로 급격하게 증가하였으며, 특히 COD/SO₄ 10에서 0.0855 m³ H₂S/kg VS로 가장 높은 결과를 나타내었다. 이러한 결과를 바탕으로, 혐기성소화에 있어 황화물의 영향은 COD/SO₄ 비율이 20 이하로 감소할 경우, 악영향을 줄 수 있는 것으로 판단된다.

• 자원환경지질
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• 제36권6호
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• pp.391-405
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• 2003

대봉 금-은광상은 선캠브리아기 경기육괴의 호상 또는 화강편마암내에 발달된 단열대(NE, NW)를 따라 충진한 중열수 괴상석영맥광상이다. 광석광물의 산출조직과 공생관계에 의하면, 이 광상의 광화작용은 여러번의 단열작용에 의해 형성된 괴상백색석영맥(광화I시기)과 투명석영시기(광화II시기)로 구성된다. 광화I기는 3회의 substages로 구분된다. 각 substage의 광석광물은 다음과 같다: 1) 광화I시기 조기=자철석, 자류철석, 유비철석, 황철석, 섬아연석, 황동석, 2) 광화I시기 중기=자류철석, 유비철석, 황철석, 백철석, 섬아연석, 황동석, 방연석, 에렉트럼과 3) 광화I시기 말기=황철석, 섬아연석, 황동석, 방연석, 에렉트림, 휘은석. 광화II시기의 광석광물로는 황철석, 섬아연석, 황동석, 방연석 및 에렉트럼이 관찰된다. 유체포유물의 체계적 연구에 의하면, 물리-화학적 상태가 상반되는 유체가 관찰된다: 1) 광화 I시기 조기와 중기 광석광물 정출과 관련된 $H_2O-CO_2-CH_4-NaCl{\pm}N_2$ 유체(조기=균일화온도: 203∼388^{\circ}C$, 압력: 1082∼2092 bar, 염농도: 0.6∼13.4wt.%, 중기=균일화온도: 215∼280^{\circ}C$, 염농도: 0.2∼2.8wt.%), 2) 광화I시기 말기와 광화II시기 광석광물과 관련된 $H_2O-NaCl{\pm}CO_2$ 유체(광화I시기 말기=균일화온도: 205∼2$88^{\circ}C$, 압력: 670bar, 염농도: 4.5∼6.7wt.%, 광화II시기=균일화온도: 201∼358^{\circ}C$, 염농도: 0.4∼4.2wt.%)이다. 광화I시기 조기의 $H_2O-CO_2-CH_4-NaCl{\pm}N_2$계 유체는 유체압력의 차이에 의해 CO_2$ 상분리가 일어났으며 광화작용이 진행됨에 따라 $H_2O-NaCl{\pm}CO_2$계 유체로 진화되었다. 또한 여기에 기원이 다른 $H_2O$-NaCl계 유체의 유입에 의해 혼입 및 희석작용으로 염농도의 감소가 있었다고 생각된다. 광화II시기 좀더 가열된 $H_2O-NaCl{\pm}CO_2$ 계 유체는 불혼합, 희석 및 냉각작용이 있었던 것으로 생각된다. 열수용액의 {\gamma}^{34}$S__{H2S}$ 값은 3.5∼7.9{\textperthansand}$로서 황은 주로 화성기원이지만 부분적으로 모암내의 황에서도 기원되었다고 생각된다. 광화유체의 산소({\gamma}^{18}O_{H2O}$)와 수소({\gamma}$D)안정동위원소값이 광화I시기에는 각각 11∼9.${\textperthansand}$, -92∼-86${\textperthansand}$, 광화 II시기에는 각각 0.3${\textperthansand}$(${\gamma}^{18}O_{H2O}$),-93${\textperthansand}$({\gamma}$D)이며, 리본-호상구조를 보이는 것으로 보아 대봉광상의 광화유체에 대한 기원과 진화과정을 두 가지로 생각할 수 있다. 1) 마그마유체로부터 광화작용이 진행됨에 따라 계속적인 순환수의 혼입이 있었으며 2) 조기 마그마${\pm}$변성유체에서 유체압력의 차에 의해 $CO_2$ 상분리와 더불어 계속적인 ${\gamma}$D가 높은 순환수의 혼입이 있었던 것으로 해석할 수 있다.있다.

• 보존과학회지
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• 제31권3호
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• pp.243-254
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• 2015

본 연구에서는 각종 재료에 의한 잠재적인 손상 검증 실험인 Oddy Test를 통해 금속유물 보존처리 과정에서 사용되는 접착제 및 코팅제를 선정하여 부식반응이 관찰된 시편으로 손상 원인을 확인하고자 한다. 6종의 접착제와 Fe, Pb, Cu, Ag 4종의 금속 시편을 사용하였다. 연구 결과, 중량 변화는 Cellulose계 접착제에 노출된 Fe시편이 29.87%로 높은 증가를 보였으며, Pb, Cu, Ag시편 순으로 증가율을 보였다. 색도 측정 결과는 Cellulose계 접착제의 변화값이 높게 나타났다. 접착제에서 발생하는 VOCs를 GC-MS로 분석한 결과, 접착제 6종 모두 Acetic acid가 검출되었다. 그 중 Cellulose계 접착제에서 다른 5종의 접착제와 비교하였을 때 1mg당 VOCs농도가 900배 이상 함량이 높았고, 소량의 Formic acid가 검출되었다. 이는 산성 불순물과 빛에 의해 촉진되기 때문으로 추측된다. 이 반응이 분자량 감소와 질소산화물과 다량의 산을 생성하는 결과가 되며 황변화 등 부식 촉진의 요인이 된다고 판단된다.