• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.78-78
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• 2017

Pure Titanium and alloy have been widely used in dental implants and orthopedics due to their excellent mechanical properties, biocompatibility and corrosion resistance. However, due to the biologically inactive nature of Ti metal implants, it cannot bind to the living bone immediately after transplantation into the body. In order to improve the bone bonding ability of titanium implants, many attempts have been made to alter the structure, composition and chemical properties of titanium surfaces, including the deposition of bioactive coatings. The PEO method has the advantages of short experiment time and low cost. These advantages have attracted attention recently. Recently, many metal ions such as silicon, magnesium, zinc, strontium, and manganese have received attention in this field due to their impact on bone regeneration. Silicon (Si) in particular has been found to be essential for normal bone and cartilage growth and development. Zinc (Zn) plays very important roles in bone formation and immune system regulation and promotes bone metabolism and growth. Manganese (Mn) is an essential trace metal found in all tissues and is required for normal amino acid, lipid, protein and carbohydrate metabolism. The objective of this work was research on the corrosion behavior of Si, Zn and Mn-doped hydroxyapatite on the PEO-treated surface. Anodized alloys was prepared at 270V~300V voltage in the solution containig Zn, Si, and Mn ions. Ion release test was carried out using potentidynamic and AC impedance method in 0.9% NaCl solution. The surface characteristics of PEO treated Ti-6Al-4V alloy were investigated using XRD, FE-SEM, AFM and EDS.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.717-725
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• 2020

The use of plant growth-promoting rhizobacteria is economically viable and environmentally safe for mitigating various plant stresses. Abiotic stresses such as flood and drought are a serious threat to modern agriculture. In the present study, the indole-3-acetic acid-producing rhizobacterium R. sphaeroides KE149 was selected, and its effects on the growth of adzuki bean plants under flood stress (FS) and drought stress (DS) were investigated. IAA quantification of bacterial pure culture revealed that KE149 produced a significant amount of IAA. Moreover, KE149 inoculation notably decreased stress-responsive endogenous abscisic acid and jasmonic acid and increased salicylic acid in plants under DS and FS. KE149 inoculation also increased proline under DS and methionine under FS. In addition, KE149 inoculation significantly increased the levels of calcium (Ca), magnesium (Mg), and potassium (K) while lowering the sodium (Na) content in the plant shoot under stress. KE149-treated plants had markedly greater root length, shoot length, stem diameter, biomass, and higher chlorophyll content under both normal and stressed conditions. These results suggest that KE149 could be an efficient biofertilizer for mitigating water stress.

• 한국분말재료학회지
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• 제8권3호
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• pp.151-156
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• 2001

MgO based nanocomposite powder including ferromagnetic iron particle dispersions, which can be available for the magnetic and catalytic applications, was fabricated by the spray pyrolysis process using ultra-sonic atomizer and reduction processes. Liquid source was prepared from iron (Fe)-nitrate, as a source of Fe nano-dispersion, and magnesium (Mg)-nitrate, as a source of MgO materials, with pure water solvent. After the chamber were heated to given temperatures (500~$^800{\circ}C$), the mist of liquid droplets generated by ultrasonic atomizer carried into the chamber by a carrier gas of air, and the ist was decomposed into Fe-oxide and MgO nano-powder. The obtained powders were reduced by hydrogen atmosphere at 600~$^800{\circ}C$. The reduction behavior was investigated by thermal gravity and hygrometry. After reduction, the aggregated sub-micron Fe/MgO powders were obtained, and each aggregated powder composed of nano-sized Fe/MgO materials. By the difference of the chamber temperature, the particle size of Fe and MgO was changed in a few 10 nm levels. Also, the nano-porous Fe-MgO sub-micron powders were obtained. Through this preparation process and the evaluation of phase and microstructure, it was concluded that the Fe/MgO nanocomposite powders with high surface area and the higher coercive force were successfully fabricated.

• Membrane and Water Treatment
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• 제14권2호
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• pp.85-93
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• 2023

Membrane separation is widely used for several applications such as water treatment, membrane reactors and climate change. Cross-linked organic-inorganic hybrid polyvinylidene fluoride (PVDF) / Tetraethyl orthosilicate (TEOS) was adopted for the preparation of optimized hollow membrane (HFM) for membrane distillation or other low pressure separators for mechanical properties and permeability under varying pretreatment schemes. HFMs were prepared on semi-pilot membrane fabrication system. Novel adopted post-treatment schemes involved soaking in glycerol, magnesium sulphate (MgSO₄), sodium hypochlorite (NaOCl), and isopropanol for different durations. All fibers were characterized for morphology using a scanning electron microscope (SEM), surface roughness using atomic force microscope (AFM), elemental composition by examining Energy Dispersive Spectroscopy (EDS), water contact angle (CA°) and porosity. The performance of the fibers was evaluated for pure water permeation flux (PWF). Post-treatment with MgSO₄ gave the highest both tensile modulus and flux. Assessment of properties and performance revealed comparable results with other organic-inorganic separators, HF or flat. In spite of few reported data on post treatment using MgSO₄ in presence of TEOS, this proves the potential of low cost treatment without negative impact on other membrane properties. The flux is also comparable with hypochlorite which manifests substantial precaution requirements in actual industrial use.The relatively high values of flux/bar for sample treated with TEOS, post treated with MgSO₄ and hypochlorite are 88 and 82 LMH/bar respectively.

• 한국초지조사료학회지
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• 제11권4호
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• pp.244-251
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• 1991

초지의 유지관리용 2종 복합비료를 개발코자 경기화학(주)의 시제품(N-P$_2$O$_{5}$-K$_2$O-MgO-B$_2$O$_3$: 14-10-12-3-0.2)을 일반단비와 공시하여 겉뿌림 혼파초지에서 유지관리용 비료로서 비효를 구명하였다. 본 시험에서 토양화학성 및 무기염기의 상호균형(I보), 수량, 식생구성비율 및 목초의 영양성분(II보)에 미치는 영향을 검토하였다. 1. 시험후 토양화학성 변화를 보면 복비구가 단비구보다 Mg함량이 약간 높고 Ca함량은 낮은 경향을 보였으나 적정함량에는 모두 미달하였다. 초지적성등급수준과 비교하면 K함량을 제외하고는 CEC, Ca, Mg 수준이 매우 낮았다. 그러나 유효 P$_2$O$_{5}$ 함량은 단비 및 복비구의 보비수준에서 적정함량(200ppm)에 달하였다. 2. 토양중 치환성 Mg함량은 K보다 낮은 수준이었다. 복비보비구만 일반작물의 critical level(0.29 me Mg/100g)에 달하였으나 목초 및 방목우를 위한 critical level(0.41 me Mg/100g)에는 전시험구가 크게 미달하였다. 3. 염기포화도에서 Ca 및 Mg함량이 바람직한 수준에 크게 미흡하였으나 상대적으로 복비구는 Mg비가높았다. 또한 Mg/K, Ca/Mg, Ca : Mg : K당량비, %Mg of CEC는 바람직한 수준에 대체로 미흡하였으나 복비구가 단비구보다 상대적으로 양호한 특성을 보였다. 4. 본 토양화학성과 연관하여 볼때 초지조성시 석회일약토 비료(토양개량제)의 시용으로 Ca 및 Mg의 기본함량의 제고가 필요하였다.

• 구강회복응용과학지
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• 제25권4호
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• pp.361-374
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• 2009

임플란트와 골 반응을 개선하기 위한 생화학적 표면 처리 방법으로 다양한 이온을 이용한 이온주입법에 대한 관심이 높아지고 있다. 본 연구는 플라즈마 상태의 마그네슘 이온을 임플란트 표면에 주입하여 이온 피막을 형성하는 방법으로 표면 처리를 한 임플란트에 대한 MC3T3-E1 골모양 세포의 초기 반응을 평가해 보고자 하였다. 티타늄 디스크를 네 가지 군으로 표면처리를 달리하였다. A군은 연마만 하였고 B군은 연마 후 마그네슘 이온을 주입하였다. C군은 알루미늄 입자분사 하였고, D군은 알루미늄 입자분사 후 마그네슘 이온을 주입하였다. 조골세포의 반응을 세포 부착, 증식, 분화의 단계별로 평가하였다. 세포 부착을 평가하기 위해 MC3T3-E1 골모양 세포를 4시간, 24시간, 48시간 금속 표면에서 배양하여 주사현미경으로 관찰하였다. 세포분화도평가는 세포를 4일간 배양 후 알칼리성 인산분해효소 활성도 분석을 통해 시행하였다. 세포외기질의 세포내 발현은 RT-PCR을 통해 평가하였다. 이상의 실험에서 다음과 같은 결과를 얻었다. 1. 주사현미경 관찰시 시간의 흐름에 따라 세포 부착량은 증가하였으며, 마그네슘 이온을 주입한 시편에서 더 많은 양 세포 증식이 관찰되었으며 분화정도도 더 높은 것으로 관찰되었다. 2. RT-PCR 분석시 알루미늄 입자분사 후 마그네슘 이온을 주입한 시편에서 c-fos와 osteonectin의 발현이 증가된 소견을 보였다. 3. 알칼리성 인산분해효소 활성도 분석시 금속 표면처리 방법에 따른 차이는 발생하지 않았다. 이상의 결과를 종합하면 Mg 이온이 주입된 군의 세포가 Mg 이온이 주입되지 않은 군보다 초기의 세포반응이 더 우수하다는 것을 알 수 있다.

• 미생물학회지
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• 제49권4호
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• pp.398-402
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• 2013

고추생장 촉진을 위해 병원균에 대한 방제력과 난용성 인산염에 대한 가용화 활성을 보이는 미생물 혼합배양액의 효과를 검증하였다. Saccharomyces sp. L13은 난용성 인산염에 대한 가용화 활성으로 분리되었으며 Bacillus sp. L32는 고추역병과 고추탄저병에 대한 길항력 활성으로 분리되었다. 특히 L32 균주는 대치배양법과 잎을 이용한 실증실험에서 모두 길항능력을 보였으며 시설재배를 이용한 실증실험에서도 병의 발병율을 저감시켰다. 두 균주의 혼합배양은 각 균주들의 생장율에 영향을 주지 않았으며 고추에 대한 혼합배양액 처리는 고추역병과 고추탄저병의 발병율을 저감시키는 동시에 난용성 인산염의 가용화를 통해 고추의 생장율을 증대시키는 효과를 확인할 수 있었다. 본 결과는 두 균주의 혼합배양액이 작물재배를 위한 미생물제제로서 잠재적 효용성이 높다는 것을 제시한다.

• 한국세라믹학회지
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• 제40권5호
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• pp.447-454
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• 2003

B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+{delta}$의 출발조성비로 99.99%의 순도를 갖는 B $i_2$ $O_3$, PbO, SrC $O_3$, CaC $O_3$, CuO 분말 시약을 사용하여 고상반응법으로 합성하였다. 이렇게 합성된 Bi계 110 K 단일상의 고온초전도 물질을 다시 분말 상태로 만든 후, AgO, A $u_2$ $O_3$, MgO 금속산화물 분말을 각각 50 wt%의 비율로 혼합하였다. AgO, A $u_2$ $O_3$, MgO의 금속분말이 혼합된 시편들을 820~85$0^{\circ}C$로 각각 최종 소결시킨 후, 각 시편들에 대하여 XRD, $T_{c}$, SEM, EDS 등의 실험을 진행하였다. 얻어진 시편들의 $T_{c}$는 순수한 Bi-2223 상보다 낮지만, AgO 금속분말을 50 wt% 혼합한 시편의 임계전이온도가 99.58 K로 A $u_2$ $O_3$나 MgO를 50 wt% 혼합한 시편들보다 더 높게 나타났다. 또한, 표면 입자(grain)의 배열 상태는 AgO 금속분말을 50 wt% 혼합한 시편이 A $u_2$ $O_3$나 MgO를 50 wt% 혼합한 시편들보다 더 치밀화 되는 경향을 나타내었다.내었다.나타내었다.내었다.

• Journal of Community Nutrition
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• 제5권2호
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• pp.105-111
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• 2003

Balanced intake of appropriate nutrients is the key to sustaining and promoting health as well as preventing and treating diseases. It is not always easy, however, to take balanced nutrition and various related factors must be taken into consideration. This report provides a summary of studies that have examined the nutrient intakes of Japanese middle-aged men and the relationship of this intake to drinking, job-related separation from families, and health practices. The alcohol consumption of Japanese middle-aged men has more than tripled in the last forty years. When nutrient intake was examined in relation to alcohol consumption, it was discovered that the maximum acceptable alcohol consumption was approximately 23 grams (about two drinks) of pure alcohol, provided the level of nutrient intake for drinkers was equal to that of non-drinkers. The alcohol energy ratio was approximately 5％. It was also discovered that middle-aged men's eating habits deteriorate when they relocate to new posts without their families and live by themselves. Compared to those living with their families, a higher proportion of those living alone have unfavorable eating habits including skipping breakfast or lunch, having a late lunch, and eating and drinking after dinner until bedtime. When Breslow's seven health practices, nutrient intake, and consumption weight by food group were examined, it was discovered that the group that had many beneficial eating and living habits consumed plenty of legume, pulses, fruit, green yellow vegetables and milk products. Their intake of vitamins and minerals was high and the results of a physical examination proved to be excellent. According to nutrition surveys conducted in Japan, China, the United Kingdom and the United States using a 24-hour recall method with common protocols and strict controls to ensure high levels of accuracy and cross-study validity, the Japanese had the highest cholesterol intake and the lowest dietary fiber intake among the four countries. Also, the alcohol energy ratio of the Japanese exceeded 8％, the highest among the four countries, while their intake of magnesium and iron was the lowest These results indicate that it is necessary to enhance nutritional education for middle-aged men and to reinforce the social environments in which they live and work in order to promote proper diet and nutrition in Japan. (J Community Nutrition 5(2) : 105-111, 2003)

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.612-619
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• 2002

The dynamic behavior of Al-Mg alloys plasma was very unstable and this instability was closely related to the unstable motion of keyhole during laser irradiation. The keyhole fluctuated both in size and shape and its fluctuation period was about 440 ${\mu}{\textrm}{m}$. This instability has been estimated to be caused by the evaporation phenomena of metals with different boiling point and latent heats of vaporization. Therefore, the authors have conducted the spectroscopic diagnostics of plasma induced in the pulsed YAG laser welding of Al-Mg alloys in air and argon atmospheres. In the air environment, the identified spectra were atomic lines of Al, Mg, Cr, Mn, Cu, Fe and Zn, and singly ionized Mg line, as well as strong molecular spectrum of AlO, MgO and AIH. It was confirmed that the resonant lines of Al and Mg were strongly self-absorbed, in particular in the vicinity of pool surface. The self-absorption of atomic Mg line was more eminent in alloys containing higher Mg. These facts showed that the laser-induced plasma was relatively a low temperature and high density metallic vapor. The intensities of molecular spectra of AlO and MgO were different each other depending on the power density of laser beam. Under the low power density irradiation condition, the MgO band spectra were predominant in intensity, while the AlO spectra became much stronger in higher power density. In argon atmosphere the band spectra of MgO and AlO completely vanished, but AlH molecular spectra was detected clearly. The hydrogen source was presumably the hydrogen solved in the base Metal, absorbed water on the surface oxide layer or H$_2$ and $H_2O$ in the shielding gas. The temporal change in spectral line intensities was quite similar to the fluctuation of keyhole. The time average plasma temperature at 1 mm high above the surface of A5083 alloy was determined by the Boltzmann plot method of atomic Cr lines of different excitation energy. The obtained electron temperature was 3, 280$\pm$150 K which was about 500 K higher than the boiling point of pure aluminum. The electron number density was determined by measuring the relative intensities of the spectra1lines of atomic and singly ionized Magnesium, and the obtained value was 1.85 x 1019 1/㎥.