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공침법에 의한 BiDy₂Fe_(5)O_(12) 결정형 나노입자 분말의 제조 및 응용 연구
홍영대,조정환,김태엽,전성욱,홍영명 고신대학교 자연과학연구소 2007 고신대학교 자연과학연구소 논문집 Vol.14 No.-
금속산화물들은 각종 산업재료로서 유용하며 더욱이 그것들의 결정형 나노입자를 경제적으로 제조하는 기술은 21세기 첨단산업에 매우 중요하다. 저자들은 前報에서 화학합성법에 의한 각종 금속산화물의 나노입자를 제조하는 표준공정법을 연구하여 보고하였다. 본 연구에서는 그 표준공정법을 이용하여, 가넷의 일종인 BiDy_(2)Fe_(5)O_(12) 결정 나노입자 분말을 제조하고 그것의 자성체로의 응용을 위해 제품특성을 조사하었다. 가네트 제조과정에 필요한 침전물은 제품설계에 의거 몰비로 계산된 Bi, Dy, Fe의 질산염들의 혼합수용액에 침전제로서 pH NH_(3)-NH_(4)CI 완충용액 일정량을 가하여 얻어졌다. 이렇게 제조된 침전은 열처리과정을 거처 BiDy_(2)Fe_(5)O_(12) 결정형 나노입자 분말로 만들어졌다. 얻어진 제품의 입자크기, 조성, 결정구조 및 광자기성 등 특성시험이 SEM, ICP, XRD, 그리고 VSM 등을 사용하여 실시되었다. 각종 분석법을 사용하여 제품의 특성을 조사한 결과, 최초에 설계한 대로의 자성체가 나노 크기의 분말로 얻어졌으며 이것을 통하여 전보에서 확립한 표준공정법의 유효성도 입증되었다. Metallic oxides are useful as various industrial materials. Futhermore, the cost-effective techniques of fabricating the crystalline nanopartides of metallic oxides are very important for the high-tech industries of the 21 century, In the previous study, the authors reported the standard process for the preparation of crystalline nanoparticles of metallic oxides by chemical synthesis, In this study, BiDyzFesOiz nanoparticles were prepared by using the reported standard process and the characteristics of the product were investigated for applicability as magnetic substance. The precipitation needed for manufacturing process of garnet was made by adding the NH_(3)-NH_(4)CI buffer solution of pH 10 to the mixed solution of bismuth (III) nitrate, dysprosium(III) nitrate and iron(III) nitrate. The amount of each nitrate was calculated by the designed mole ratios. The nano-size crystalline powders of BiDy_(2)Fe_(5)O_(12) were earned by heating the precipitation at 800℃ for 4 hours in air. The characterizations, such as particle size, composition, crystal structure and magneto-optical property of garnet were tested by SEM, ICP, XRD, and VSM analyses. The results of the analyses showed the following two facts. First, a good magnetic substance of BiDy_(2)Fe_(5)O_(12) was earned as crystalline nano-size powders according to the original design. Next, the established standard process for the fabrication of METALLIC oxides nanonartieles was approved as a very effective method.
Hot Embossing 공정이 광소자 치수 정밀도에 미치는 영향
정명영(Myung-Yung Jeong),김병철(Byeong-Cheol Kim) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5
In order to obtain the accuracy of an optical waveguide, we have measured the dimensional change of<br/> optical waveguide after hot embossing. As the parameters, we selected embossing temperature, pressure,<br/> material viscosity and cooling temperature. As results, we present in this paper the hot embossing conditions<br/> which contain temperature to 40℃ above Tg and the pressure about 2.9 MPa and viscosities to 108 Pa.s.<br/> Cooling temperature has a little influence on the dimensional change of embossed structure.
정명영(Myung Yung Jeong) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4
A feasibility study for the fabrication of master replication with nanostructures by Nanoimprint<br/> Lithography (NIL) was investigated for application of polymer Photonic Bandgap (PBG) devices used in<br/> photonic IC. Large area gratings of 9 15 () with p = 400 was successfully embossed on PMMA on<br/> silicon wafer and the embossing parameters (temperature, pressure, time) were established. A precise control<br/> of Oplasma Reactive Ion Etching (RIE) process time allowed window opening over the whole area despite<br/> the presence of wafer bending. Master replication with aspect ratio 1 was successfully fabricated, but master<br/> replication with aspect ratio 3 needs to optimize parameters. All replications were done in a NIL process.
( Myung-a Jung ),( Jawon Shin ),( Ara Jo ),( Huwon Kang ),( Gyuok Lee ),( Dool-ri Oh ),( Hyo Jeong Yun ),( Sojeong Im ),( Donghyuck Bae ),( Jaeyong Kim ),( Chul-yung Choi ) 한국응용생명화학회(구 한국농화학회) 2020 Journal of Applied Biological Chemistry (J. Appl. Vol.63 No.4
Testosterone deficiency syndrome (TDS), also known as late-onset hypogonadism, is a clinical and biochemical syndrome associated with advanced age and characterized by deficient serum testosterone levels. The Elaeagnus multiflora fruit (EMF) and Cynanchum wilfordii (CW) have been used in traditional herbal medicine. This study aimed to investigate the therapeutic effects of EMF and CW mixtures (at the ratios of 3:7, 5:5, and 7:3) on TDS using TM3 cells and aging male rats. EMF, and mixtures of EMF and CW (at the ratios of 3:7, 5:5, and 7:3) significantly increased testosterone levels in TM3 cells (p <0.05). The rats were orally administered EMCW (EMF and CW mixed at the ratio of 3:7 50, 100 and 200 mg/kg/day) for 4 weeks consecutively. After 4 weeks of EMCW administration, latency time on the rotarod test, and serum testosterone and dehydroepiandrosterone sulfate levels were significantly increased (p <0.05 and p <0.01). Moreover, the levels of globulin-bound sex hormones were decreased in the EMCW-fed groups. However, prostate-specific antigen levels did not differ among the groups. These results suggest that EMCW can be effectively used to alleviate TDS.
地震波의 不規則한 走時曲線에 의한 花崗土 地盤의 動的 土質定數 推定
鄭斗永,李義明 全北大學校 1989 論文集 Vol.31 No.-
In this study, in a case of the irregular Time-Distance Curves the analysis method was studied, therefore this method was used for evaluation of dynamic soil parameter in the weathered granite soil. Then, the utilization of the concept of a delay time and the application of phantoming was to evaluate the time-distance for the refracted waves in a measuring line and the depth in the detector point. From the results it was found that how much was Poisson's ratio influenced in the relationship between Vp and E, and Vs and G, and these data related in the correlation between N-values and Vs.