붕소제거제의 제조에 관한 연구

최규만(Choi, kyu-man),이윤식(Lee, yun-sik) 한국정보전자통신기술학회 2009 한국정보전자통신기술학회논문지 Vol.2 No.3

심층수를 음용수화 하는 것은 심층수에 포함되어 있는 붕소 때문에 크게 제약을 받고있다. 붕소는 사람과 식물에게 유독한 것으로 보고되고 있다. 이러한 붕소를 제거하는 유용한 방법이 몇 가지 있는데, 본 논문에서는 해수에 포함된 붕소를 제거하기 위한 붕소제거제를 폴리머 레진 형태로 합성 하였다. 합성된 레진을 IR분석을 통해 특성을 분석하였고, SEM을 이용하여 그 표면을 관찰하였다. 붕소제거능력을 평가하기 위해 레진을 직경이 0.25mm, 0.5mm 및 1.0mm가 되도록 구분하여 준비하고 베치방식의 실험을 통해 그 결과를 관찰했다. The use of deep water as drinking water is greatly limited of significant concentration of boron in sea water. Boron is reported to be toxic for human and plants. Some of possible methods are available to remove boron. The polymeric resins were synthesized to remove the boron from the sea water. The resin was characterized with IR analysis and the morphology was discussed with SEM images. To assess boron removal capacity of the resin, it was distributed in three different bead size i.e., 0.25mm, 0.5mm and 1.0mm. The removal behavior of this resin was examined under the batch experiments.

한국의 아름다운 터널을 찾아서

최규만(Kyu-Man Choi) 대한토목학회 2010 대한토목학회지 Vol.58 No.8

Design and analysis of the lens converting the spot light into the line light

Choi, Kyu-Man(최규만),Lee, Hae-Chun(이해춘) 한국정보전자통신기술학회 2008 한국정보전자통신기술학회논문지 Vol.1 No.2

A CCFL which commonly used in the back light units for the LCD, possess very high brightness hence, was widely used as a line light source. However, the use of CCFL, caused for several environmental concerns since it contain highly toxic mercury, gradually replaced into a LED. But the LED is a spot light source, the dark area occurs in the surface of the back light units. In this paper, we proposed the lens that can convert the spot light into the line light and it can remove the dark area in the surface of the back light units. The lens is composed with the light condensation part and the light guiding part. The conditions obtained will be helpful to plan an optimum structure for such preparation.

Preparation and Characterization of Small Sized PZT Powders

Choi, Kyu-Man(최규만),Lee, Hae-Chun(이해춘) 한국정보전자통신기술학회 2008 한국정보전자통신기술학회논문지 Vol.1 No.2

A current research basically diverted towards an increase in the operational output with the minimization of the materials used, which ultimately scaled down the dimensions of ceramic electronic components. In this direction the nano-technology pave the revolutionary changes in particular the electronic industries. The applications of nano-sized particles or nano-sized materials are hence, playing a significant role for various purposes. The PZT(lead, zirconium, titanium) based ceramics which, are reported to be ferroelectric materials have their important applications in the areas of surface acoustic waves (SAW), filters, infrared detectors, actuators, ferroelectric random access memory, speakers, electronic switches etc. Moreover, these PZT materials possess the large electro mechanical coupling factor, large spontaneous polarization, low dielectric loss and low internal stress etc. Hence, keeping in view the unique properties of PZT piezoelectric ceramics we also tried to synthesize indigenously the small sized PZT ceramic powder in the laboratory by using the modified sol-gel approach. In this paper, propyl alcohol based sol-gel method was used for preparation of PZT piezoelectric ceramic. The powder obtained by this sol-gel process was calcined and sintering to reach a pyrochlore-free crystal phase. The characterization of synthesized material was carried out by the XRD analysis and the surface morphology was determined by high resolution scanning electron microscopy.

새로운 녹화 블록을 이용한 보강토 옹벽

최규만(Choi Kyu Man),심태보(Sim Tae Bo),강세구(Kang Se Gu),공학봉(Gong Hak Bong),이상덕(Lee Sang Duk) 대한토목학회 2009 대한토목학회 학술대회 Vol.2009 No.10

Influence of HMDS additive on the properties of YAG:Ce nanophosphor

Choi, Kyu-Man(최규만),Kim, Yeo-Hwan(김여환),Lim, Hae-Jin(임해진),Yoon, Sang-Ok(윤상옥) 한국정보전자통신기술학회 2011 한국정보전자통신기술학회논문지 Vol.4 No.1

YAG:Ce 형광제 제조에 있어서 공침(co-precipitation) 후 n-butanol 공비증류(azeotropic distillation)시 HMDS(hexadimethyldisilazane)를 첨가하였을 때, 형광체가 광학특성에 미치는 영향에 관하여 연구하였다. 물과 유기용제에 의한 공비증류 시 유기용제의 분자량이 크면 표면의 수소결합이 유기용제로 치환됨으로서 표면장력을 감소시켜 분체의 원형화(conglobation)와 응집(agglomerate)을 감소시키므로 유기용제로 n-butanol보다 분자량이 큰 HMDS을 첨가하였다. N-butanol 만을 사용한 형광체가 HMDS를 첨가한 것 보다 응집(agglomerate)되는 현상이 감소하였으며 우수한 광학적 특성을 나타내었다. Influence of hexamethyldisilazane(HMDS) in post processing technique by using n-butanol azeotropic distillation on the luminescence properties of YAG:Ce nanophosphor were studied. The organic solvent(n-butanol) azeotropic distillation which prevent powders from conglobation since lager molecules decrease the surface tension and more complete replace the residual water in the precipitate. HMDS that had larger molecules than that of n-butanol was added in azeotropic distillation. The phosphor synthesized from n-butanol azeotropic distillation exhibited lower agglomerate and better photoluminescence properties than that from HMDS added heterogeneous azeotropic distillation.

미생물 연료전지의 전극 재료와 구조에 따른 전기적 특성

최규만,Choi, Kyu-man 한국정보전자통신기술학회 2014 한국정보전자통신기술학회논문지 Vol.7 No.1

폐수 속에 들어있는 미생물을 이용해서 전기를 얻을 수 있도록 고안된 것이 미생물 연료전지이다. 본 논문에서는 미생물 연료전지의 전극 재료와 구조에 따른 전기적 특성을 조사했다. 구리판을 캐소드 전극으로 사용한 연료전지는 구리판의 산화 반응에 따른 전압역전현상이 관찰되어 백금판을 전극으로 사용한 연료전지보다 낮은 출력 전압을 나타내었다. 구리판을 전극으로 사용한 경우 전극판의 간격이 작을수록 높은 전압특성을 나타내었고 면적이 넓을수록 최고출력전압이 나타나는 시간이 지연되는 특성을 보였다. MFC(microbial fuel cell) is the device to produce the electricity by using the microbes which are living in the waste water. In this paper, the electric characteristics of the MFC were investigated according to each different structure and electrode materials. The voltage being reversed phenomenon was observed in the MFC which uses the cupper plate as the cathode material. This result comes from the oxidation reaction of the cupper plate electrode in this MFC. And this MFC has lower output voltage than one that has a platinum plate electrode. The smaller gap distance of the cupper plate electrode of the MFC showed the higher output voltage. The larger electrode area of the cupper plate electrode showed that the reaching time of the output voltage to the maximum value was delayed.

졸-겔법을 이용한 TiO₂ 박막의 광촉매 특성

최규만(Choi, Kyu-Man),김여환(Kim, Yeo-Hwan),임해진(Lim, Hae-Jin) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.2

TiO₂ 박막을 저온 열처리 졸-겔 법으로 합성하였다. 박막의 기판은 면적이 100㎟인 붕규산염 유리를 사용 하여 시료를 300˚C부터 11000C까지 열처리하였고, 이때 제조된 박막의 두께는 약 1.5μm정도였다. 300˚C에서 2시 간 동안 열처리한 TiO₂ 박막은 아나타제 상을 나타내었고 열처리 온도가 증가함에 따라 비정질 상태에서 아나타제 상과 루타일 상이 공존하면서 각 상의 분율이 변화하였다. SEM 분석에 의하면 박막의 입자 크기는 0.1∼0.54μm이었 으며 Uv-visible 반사특성에 있어서 390nm부근에서 광흡수가 되는 것을 알 수 있었다. 따라서 낮은 열처리 온도에서 생성된 TiO₂ 박막은 주로 아나타제 상을 가지며 광촉매 특성을 2.4배 증가시키는 것으로 나타났다. Thin film of TiO₂ was obtained by the sol-gel dip method on the brosilicate glass substrate. It was found that the film was about 1.5μm thick as obtained by 4 successive coatings and annealed at varied temperatures ranged from 300˚C to 1100˚C for 2 hrs. The substrate used was having the surface area of 100㎟. Increasing the annealing temperature caused to change in mineralogical phase of titanium oxide i.e.., amorphous, crystalline antase to rutile phases. The particle size of the titanium oxide film were ranged from 0.1~0.54μm estimated by the SEM analysis. The material showed an absorbance maximum at the wavelength 390nm obtained by UV-visible spectrophotometer. These results therefore, indicated that the TiO₂ film obtained relatively at low annealing temperature consisted predominantly with anatase phase; possessed higher photocatalytic behavior i.e., 2.4 times higher than that of only UV lamp irradiation.

하소조건이 YAG:Ce형광체 특성에 미치는 영향

최규만(Kyu-Man Choi),김재문(Jae-Moon Kim),이준모(Joon-Mo Lee) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

보론 소거용 레진의 제작 및 특성

최규만(Kyu-Man Choi),이승목(Seung-Mok Lee),이윤식(Yun-Sik Lee),이상훈(Sang-Hun Lee) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.11

The resin that can be used as the sorbent to eliminate boron in the deep sea water was fabricated. Cellulose fiber(CF), Glycidyl methacrylate(GMA), Sodiumn-dodecyl sulfate(SDS), aqueous hydrogen peroxide and aqueous thiourea dioxide have been prepared and used as support. This support was reacted with vinyl monomer and N-methylglucamin.. The resulting resin was such an efficient sorbent to eliminate boron that the resin showed reasonably good sorption ability. By appling this resin to the deep sea water, boron concentration changed from 5.631ppm (before) to 3.477ppm(after)