• 한국재료학회지
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• 제28권10호
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• pp.578-582
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• 2018

ZnO crystals with different morphologies are synthesized through thermal evaporation of the mixture of Zn and Cu powder in air at atmospheric pressure. ZnO crystals with wire shape are synthesized when the process is performed at $1,000^{\circ}C$, while tetrapod-shaped ZnO crystals begin to form at $1,100^{\circ}C$. The wire-shaped ZnO crystals form even at $1,000^{\circ}C$, indicating that Cu acts as a reducing agent. As the temperature increases to $1,200^{\circ}C$, a large quantity of tetrapod-shaped ZnO crystals form and their size also increases. In addition to the tetrapods, rod-shaped ZnO crystals are observed. The atomic ratio of Zn and O in the ZnO crystals is approximately 1:1 with an increasing process temperature from $1,000^{\circ}C$ to $1,200^{\circ}C$. For the ZnO crystals synthesized at $1,000^{\circ}C$, no luminescence spectrum is observed. A weak visible luminescence is detected for the ZnO crystals prepared at $1,100^{\circ}C$. Ultraviolet and visible luminescence peaks with strong intensities are observed in the luminescence spectrum of the ZnO crystals formed at $1,200^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• 제27권4호
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• pp.295-301
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• 1997

Nitrendipine, a slightly soluble calcium channel blocking agent forms a solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$, which exhibits better dissolution characteristics than the uncomplexed drug. The dissolution rate of nitrendipine was markedly increased in solid dispersion system in pharmacopeial disintegration media at pH 1.2 and pH 6.8. Four different dosage forms of nitrendipine were administered to rats: (a) nitrendipine in the solution of PEG 400; (b) nitrendipine solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 by solvent evaporation method and administered in capsule form; (c) physical mixture of nitrendipine with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 and administered in capsule form; (d) nitrendipine alone administered in capsule form. Relative bioavailability after the oral administration of various dosage forms to rats with a dose of 10 mg/kg equivalent to nitrendipine was compared with that of nitrendipine in the solution of PEG 400. The AUC of solid dispersion was significantly bigger than that of nitrendipine powder. $T_{max}$ of solid dispersion was significantly shorter and $C_{max}$ was higher than that of nitrendipine powder. These results indicate that the bioavailability of nitrendipine could be improved markedly by inclusion complexation. An interesting correlation also appears to exist between the in vitro dissolution data and the area under the plasma concentration-time curves.

• 유기물자원화
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• 제10권4호
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• pp.81-85
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• 2002

유박을 원료로 한 유기질비료, 미생물제제 및 해초추출물의 시용효과를 규명하기 위하여 엇갈이배추를 공시작물로 시설하우스에서 재배하면서 생육 및 수량을 조사하였다. 유기질비료 처리구에 미생물제제를 혼용한 처리구에서 수량이 가장 좋았으며, 과량 처리구에서도 비해가 발생하지 않았다. 해초추출물의 엽면시비와 관주에 의한 수량증대는 관주처리구가 다소 높았으며, 또한 미생물제제의 경우 액상보다 분말처리구에서 수량이 높게 나타났다. 즉, 미생물제제의 형태에 있어서는 분말이 해초추출물의 시용방법에 있어서는 관주에 의해 생육이 안정되었으며, 수량도 높은 경향을 보였다. 결론적으로 유기질비료의 2배 과량처리구에서 비해가 발생되지 않았으며, 미생물제제와 해초추출물의 시용으로 생육 및 수량이 향상되었다.

• 한국식품영양학회지
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• 제5권2호
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• pp.90-98
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• 1992

This study was divised to observe the effects of defatted(by petroleum ether) Korean ginseng on the cholesterol level of Sprague-Dowley Albino male rats by alternating the diet. 130 heads of weaned rats having 83$\pm$4g of body weight were fed with each stock diets supplemented with 0.5, 1.0 and 3.0% defatted ginseng powder for 4 or 8 weeks, and after that fed with stock diet only for 8 or 4 weeks. Total cholesterol and free form cholesterol contents in serum, liver and aorta of them were determined, and compared with the each corresponding group which was fed with defatted ginseng control diet for 12 weeks. Total cholesterol and free form cholesterol contents in the serum were increased caused by the alternating diets which was fed on 0.5, 1.0 and 3.0% defatted ginseng diet for 4 and 8 weeks after being fed on stock diet for 8 and 4 weeks, conversely total cholesterol contents in the aorta were decreased by the same alternating diets. Free form cholesterol contents in the serum, liver and aorta of the group which was fed on 1.0% defatted ginseng diet 8 weeks after being fed on stock diet for 4 weeks were increased, but that of the group which was fed alternately on 3.0% defatted ginseng diet were decreased than the corresponding defatted ginseng control diet group.

• 한국축산식품학회지
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• 제40권3호
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• pp.388-400
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• 2020

This study was conducted to develop chicken meat patties by incorporating pomegranate peel and bagasse powders and their extracts. Patties were developed by incorporating pomegranate peel powder (PPP, 2 g), pomegranate aril bagasse powder (PABP, 4 g), pomegranate peel powder aqueous extract (PPAE, 6 g) and pomegranate aril bagasse powder aqueous extract (PABAE, 9 g) individually per 100 g of minced meat. Both types of powders and extracts treated patties had significantly higher total phenolic content than control and butylated hydroxytoluene (BHT) treated patties. Both types of powder (PPP and PABP) treated patties had significantly higher water holding capacity, ash, crude fibre content, and hardness values, and significantly lower moisture content and lightness values in comparison to control patties. Emulsion stability and cooking yield of PABP treated patties were significantly higher than control. Addition of extracts and BHT did not influence the physico-chemical properties and proximate composition of chicken patties. Both types of powders and extracts provided better protection to chicken meat patties against oxidative rancidity and microbial proliferation in comparison to control and BHT treated patties during refrigerated storage. It is concluded that pomegranate fruit byproducts in the form of peel powder, aril bagasse powder and their extracts can be successfully utilised in development of healthier chicken meat patties and these byproducts can also be effectively used as a replacement of synthetic antioxidants such as BHT.

• 한국분말재료학회지
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• 제24권5호
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• pp.384-388
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• 2017

The effect of the mixing method on the characteristics of hybrid-structure W powder with nano and micro sizes is investigated. Fine $WO_3$ powders with sizes of ${\sim}0.6{\mu}m$, prepared by ball milling for 10 h, are mixed with pure W powder with sizes of $12{\mu}m$ by various mixing process. In the case of simple mixing with ball-milled $WO_3$ and micro sized W powders, $WO_3$ particles are locally present in the form of agglomerates in the surface of large W powders, but in the case of ball milling, a relatively uniform distribution of $WO_3$ particles is exhibited. The microstructural observation reveals that the ball milled $WO_3$ powder, heat-treated at $750^{\circ}C$ for 1 h in a hydrogen atmosphere, is fine W particles of ~200 nm or less. The powder mixture prepared by simple mixing and hydrogen reduction exhibits the formation of coarse W particles with agglomeration of the micro sized W powder on the surface. Conversely, in the powder mixture fabricated by ball milling and hydrogen reduction, a uniform distribution of fine W particles forming nano-micro sized hybrid structure is observed.

• 한국분말재료학회지
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• 제29권1호
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• pp.14-21
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• 2022

In the powder bed fusion (PBF) process, a 3D shape is formed by the continuous stacking of very fine powder layers using computer-aided design (CAD) modeling data, following which laser irradiation can be used to fuse the layers forming the desired product. In this method, the main process parameters for manufacturing the desired 3D products are laser power, laser speed, powder form, powder size, laminated thickness, and laser diameter. Stainless steel (STS) 316L exhibits excellent strength at high temperatures, and is also corrosion resistant. Due to this, it is widely used in various additive manufacturing processes, and in the production of corrosion-resistant components with complicated shapes. In this study, rectangular specimens have been manufactured using STS 316L powder via the PBF process. Further, the effect of heat treatment at 800 ℃ on the microstructure and hardness has been investigated.

• 대한한의정보학회지
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• 제18권1호
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• pp.64-77
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• 2012

Donguibogam, Korea's cultural heritage and traditional Oriental medicine book listed in the World Heritage three years ago, is indeed great in its importance and value. Korea's posterity has sought treatment methods through the medical book and their researches on that book have continued. However, it is rare to make the concrete analysis on the medicines for prescriptions recorded in the book. In this study, we reviewed "Ears" in the Section "Bodily Appearance" among the five chapters of Donguibogam, and analyzed the 55 types of prescriptions for ear diseases, the medical characteristics, tastes, prime classification of medical herbs, and acupunctural effects, and the dosage forms depending on prescriptions. For insect-entering ear diseases and 20 kinds of a single-medicine prescription also, the treatments are presented in the book, but we presented the texts only and excluded them in the analysis. We also excluded overlapping prescriptions and adding and reducing prescriptions of the 55 prescriptions, and thus classified the left 42 proscriptions by dosage form. As a result: 1. With respect to medical characteristics, the medicine with warm characteristics reached 9 types(40.9%), the highest rate, followed by the medicine with cold characteristics 8 types (36.4%). 2. Concerning medical tastes, the medicine with bitter taste included 12 types (54.5%), the medicine with sour taste 10 types (45.5%), and the medicine with sweet taste 7 types (31.8%). It was unusual that of the 22 medicines used for multipurpose, no medicine with the taste was found. 3. For the acupunctural effects, the medicine with acupuncture effects for spleen medirian reached 12 types in total (54.5%). On the contrary, the medicine with the effects for pericardium meridian reached only one (4.5%) among the total of 22 medicines. 4. In the dosage form of 42 prescriptions, powder medicine was 15 types (35.7%), and decoction medicine was 14 (33.3%). Powder, dedoction, and pill medicines accounted for 90.4% of the total medicine type. It was found that in particular, for ear diseases powder medicine was used more frequently than decoction medicine.

• 청정기술
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• 제26권2호
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• pp.116-121
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• 2020

본 연구에서는 유가금속 회수를 한 전기차 폐배터리 부산물의 재활용에 관하여 연구하였다. 폐배터리 부산물에는 희토류들이 남아있으나, 부산물의 형태로는 소재로서의 가치가 없기에 정제과정을 거쳐 희토류 산화물로 회수하였다. 희토류침전분말 형태의 부산물을 30% 수산화나트륨을 이용하여 가공이 편한 수산화물로 변환한 뒤, 옥살산의 용해도 차이를 이용하여 남아 있는 불순물을 정제한 뒤, D2EHPA (Di-(2-ethylhexyl) phosphoric acid)를 사용하여 이트륨을 분리하였다. 과망가니즈산 칼륨을 이용하여 세륨을 분리 후, PC88A (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester)를 사용하여 란타넘과 네오디뮴을 분리하였다. 그 후 800 ℃의 온도에서 소성하여 란타넘, 네오디뮴 산화물로 재생하는 방법을 확인하였다.

• 대한기계학회논문집A
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• 제34권10호
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• pp.1543-1548
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• 2010

분말단조 공정은 정형의 자동차부품을 제작하는데 널리 이용되고 있다. 분말야금이란 금속 원료 분말을 사용하여 원하는 제품의 형태로 성형을 한 다음 적정온도에서 소결하여 필요한 금속 제품을 제조하는 기술을 말한다. 본 연구에서는 자동차 엔진의 경량화를 위한 피스톤 제작에 관한 것이다. 분말단조로 제작 되어진 엔진 피스톤의 특성을 유한요소해석을 통해서 알아보겠다. 유한요소해석은 DEFORM/3D 를 이용해서 성형성을 평가하도록 하겠다. 성형온도, 구배각도, 마찰계수의 변화에 따른 피스톤의 성형성을 알아보겠다.