천연식물유황(MSM; Methyl Sulfonyl Methane) 급여가 오리 사육성적에 미치는 영향

황윤화,정호진,이영,황보식 한국가금학회 2010 한국가금학회 정기총회 및 학술발표회 Vol.27 No.-

The objective of this study was to determine the effect of MSM (methyl sulfonyl methane) supplementation on growth performance in ducks. Three experiments were carried out to investigate the effect of level and feeding period of dietary MSM and Monacus culture on the performance.0.0(C), 0.025(T1), 0.05(T2), and 0.03%(in 0.025% Bacillus subtillus at 1×10?cfu/g and 2.5% Monacus culture, T3) of MSM was added to commercial duck diets, respectively, and fed during 42 days of age. As a result, Treatment Ⅲ of growth performance (mortality, feed conversion rate , market weight, uniformity, etc.) were identified as the most outstanding.

오리육의 항산화 효과

정호진,황윤화,이영,황보식 한국가금학회 2010 한국가금학회 정기총회 및 학술발표회 Vol.27 No.-

This study performed to evaluated extraction(TRT1; breast of duck meat extracted with water, TRT2; breast of duck meat extracted with 50% ethanol, TRT3; thigh of duck meat extracted with water, TRT4; thigh of duck meat extracted with 50% ethanol) and addition level(0.05, 0.1, 0.25, 0.5, 1.0, 2.0%) of duck meat on antioxidant activity. As a result, iron chelation activity of duck meat extracted with 50% ethanol were showed higher levels than duck meat extracted with water. Especially TRT2 showed nearly 90% at 2% level. Reducing power of both extracts showed low rate at all level. DPPH radical scavenging activity of breast extracts were showed higher over 0.5% levels than thigh extracts.

Relaxation and Phase-transition Characteristics of Relaxor Ferroelectric Potassium Lithium Niobate

전병옥,정중현,최병춘,황윤화 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.11

The electric modulus relaxations were considered to be coupled phenomena between the polarization fluctuations < P2 > due to local symmetry breaking and ionic hopping through nearest neighbor sites. The Nb-rich potassium lithium niobate (K5.595Li3.125Nb11.28O30) crystals exhibited a ferroelectric diffused phase transition around the dielectric maximum temperature Tmax = 350 C. The electric modulus relaxations were characterized by using the Cole-Davidson distribution of the electric modulus relaxation times at frequencies ranging from 100 Hz to 1 MHz. Although the lattice constants along the a-axes and the c-axes and the tetragonal unit cell volume showed linear expansions with increasing temperature T, the axial ratio c/a decreased with increasing T at temperatures below the Burn’s temperature TB = 550 C. The dielectric relaxation accompanied the high ionic conduction in the temperature range above Tmax = 350 C. The ac conductivity 0(!) was analyzed by using the formulae 0(!)/dc = 1 + (!/!O)n, where !O is the crossover frequency. It was considered that a double-Arrhenius behavior of the dc conductivity dc at temperatures around the Burn’s temperature TB = 550 C was suspected of thermally activated motions in the random distribution of oxygen vacancies and lithium ions. The ac universality could result in a disordered configuration of the mobile ions, i.e., the dc conductivity at temperatures above TB. The slow relaxations of the nano-sized polar regions may contribute to the dc conductivity dc at temperatures below TB. The characteristic relaxation time CD showed a change in activation energy from 1.08 eV to 0.80 eV at temperatures around TB. The scaling factor " ·T/"0 1 increased in proportion to (TB − T) at T < TB, but was almost constant at T > TB, where "0 1 is the high frequency dielectric constant and T is the temperature in Kelvin.

Impact of synthesis routes on the chemical, optical, and electrical properties of graphene oxides and its derivatives

김영재,강영호,김나라,이종훈,황윤화,이선민,최성묵,김원배,이광희 한국물리학회 2015 Current Applied Physics Vol.15 No.11

Solution-processed graphene oxides in their reduced forms are prominent prospective functional materials for organic optoelectronics. For graphene oxide synthesis, several methods have been developed, which induce varying properties in their products. However, the dependence of the graphene oxide properties on their synthesis methods has rarely been studied, hindering the selection of the optimum synthesis route for a target application. In this study, we report our study results on the properties of synthesized graphene oxides and their reduced forms created using several synthesis methods, such as the modified Hummers' method, the improved method, and the Staudenmaier's method as well as from two commercial sources, Angstron Material, Inc. and Graphos, Inc. Focusing on the transparent electrode application, the properties of thin films were investigated using UVevisible spectroscopy, Hall measurements, atomic force microscopy, Raman spectroscopy, work function measurements, and X-ray photoelectron spectroscopy. Our results reveal significant morphological, elemental, structural, and optoelectrical property variations among the as-prepared and reduced thin films of graphene oxides by their synthesis methods. In addition, the results show that the graphene oxides synthesized using the modified Hummers' method and the product from Angstron Material, Inc. are the most suitable materials for the transparent electrode application.

소규모 해수담수화시설 물 생산량 제고 방안 - 전라남도 해수담수화시설을 중심으로 -

정용문,오은하,박현수,김민영,송승리,김학림,차윤경,한용원,황윤화,김익산,박귀님 한국도서(섬)학회 2024 한국도서연구 Vol.36 No.1

Desalination was a water treatment process that involved converting saline water to fresh water. Desalination generated an estimated 0.03 hundred million ㎥/day of fresh water in Korea. But, water shortage problems in the island area were not solved regarding the low capacity of desalination plants, the low amount of available salinity groundwater, etc. Furthermore, the low recovery rate of freshwater, lack of expertise of local operators, water leakage and contamination by old pipelines needed to be improved. This study used a reverse osmosis system projection program to compare compared desalination processes to improve water production and decrease electricity consumption. It was investigated that over 80 % of small-scale desalination plants in Jeollanam-do produced 50 ㎥/day. The total dissolved solids of feed water were at least 115 mg/L, up to 28,273 mg/L, an average of 5,676 mg/L, and the water temperature of raw water was at least 5.2 ℃, up to 28.1 ℃, and the average of 17.0 ℃. Based on the investigation results, plant capacity and the total dissolved solids of the final freshwater for performance simulation were set at 50 ㎥/day, 500 mg/L, and the total dissolved solids and temperature of raw water were set at 6,500 mg/L, and 17 ℃. The process compared and analyzed changes in the quality and quantity of freshwater by designing the ‘1st RO’ process, the ‘1st RO + ERD’ process with an energy recovery device added, the ‘1st RO + Recirculation’ process, and the ‘2nd RO + Recirculation’ process. In the ‘1st RO’ process, 200 ㎥/day of feed water was required to produce 50 ㎥/day of fresh water, but in the ‘1st RO + Recirculation’ process and the ‘2nd RO + Recirculation’ process, the amount of feed water required could be reduced to 83.3 ㎥/day and 66.7 ㎥/day. The ‘1st RO’ process consumed 1.47 kWh/㎥. However, in the ‘1st RO + ERD’ process, it is lowered to 0.45 kWh/㎥. The recovery rate was increased by 75 % in the ‘2nd RO + Recirculation’ process. Finally, reducing the electric energy consumed in freshwater production in summer was possible. When replacing old desalination plants or installing new ones, the ‘1st RO + ERD’ process, which can lower electricity consumption, should be considered rather than the ‘1st RO’ process, the ‘1st RO + Recirculation’ process and the ‘2nd RO + Recirculation’ process, which could increase waster production.

전라남도 농업용 시설하우스의 실내공기질 특성 연구

김학림 ( Hak-lim Kim ),박보영 ( Bo-young Park ),송승리 ( Seung-ri Song ),김인열 ( In-yeol Kim ),정용문 ( Yong-moon Jung ),김수진 ( Soo-jin Kim ),한용원 ( Yong-won Han ),황윤화 ( Yun-hwa Hwang ),이정일 ( Jeong-il Lee ) 한국환경기술학회 2025 한국환경기술학회지 Vol.26 No.2

This study was conducted to investigate the characteristics of air quality in agricultural greenhouses in Jeollanam-do. Indoor air quality was measured and analyzed at 32 greenhouses in 2024. The survey results indicated that the concentrations of PM-10, CO₂, HCHO, and Radon (²²²Rn) complied with indoor air quality control standards or guidelines established by Indoor Air Quality Control Act in Korea. On the other hand, the concentration of total airborne bacteria exceeded the standards in five sites. In the case of airborne fungi, the concentration exceeded the guidelines at most sites, with the exception of only three sites. The concentration of Radon was the highest at 7 a.m., exceeding the indoor air quality standards, but was the lowest at 3 p.m. in most agricultural greenhouses. The presence of mold and radon adversely affects the respiratory system of the worker, so it must be discharged through ventilation or wearing protective equipment such as masks before working.