초음파 분무 열분해법에 의한 $SrTiO_3$ 미분말 합성시 그 형성 과정에 관하여

허화범,이동주,신건철 한국결정성장학회 1992 韓國結晶成長學會誌 Vol.2 No.2

$SrTiO_3$미분말은 초음파 분무 열분해법으로 chloride와 nitrate 수용액을 출발용액으로 사용하여 농도를 0.05M과 0.1M로 하였으며 각 농도에 따른 유속의 변화를 0.5cm/sec로 변화시켜 합성하였다. 분말의 형성 과정은 0.05M, 0.05cm/sec 조건에서 단계별 분말을 합성하여 주로 morphorlogy 측면에서 고찰하였다. 출발용액이 chloride 수용액인 경우 SrTiO$_3$미분말을 합성할 수 없었으며 nitrate 수용액인 경우 모든 조건에서 (110)면을 주 peak로 하는 cubic의 순수한 구형의 $SrTiO_3$미분말을 얻을 수 있었다. 평균입자의 크기는 유속이 증가함에 따라 $0.49{\mu}m$에서 $0.55{\mu}m$로 증가하였다. 출발액적의 크기는 $14.3{\mu}m$이었으며 단계별 입자의 형태는 1, 2단계에서 용매의 증발에 의해 매우 porous하였으며 불규칙하였고, 3, 4, 5단계를 지나는 동안 점차 둥근 형태로 형성되었다. $SrTiO_3$powders were synthesized from the chloride and the nitrate aqueous solution by spray pyrolysis method using ultrasonic vibrator. The concentration of mother solution was prepared 0.05M and O.lM. The carrier gas flow rate was 0.5cm/sec and 1.5cm/sec, respectively. The formation processing was investigated in the 0.05M and 0.05cm/sec. The $SrTiO_3$powders could not be synthesized from chloride aqueous solution. The prepared powders from nitrate aqueous solution was SrTi03 with cubic structure and nearly sphere particle for all samples. Mean particle size was increased from $0.49{\mu}m$ to $0.67{\mu}m$ by changing the carrier gas flow rate from O.5cm/sec to 1.5cm/sec. Also, mean particle size increased from $0.49{\mu}m$to $0.55{\mu}m$by changing the concentration of mother solution from O.05M to O.1M. Atomizing droplet size was $14.3{\mu}m$. The shape of particles was very porous by evaporation of solvent at the initial step. But through the each step upwards, shape of particles was formed themselves into a nearly roundish.

요업 원료로 재활용하기 위한 석탄회의 처리 : II. 채취조건 및 수비선별시 pH의 영향

허화범,정철원,박종현,신건철 한국결정성장학회 1996 韓國結晶成長學會誌 Vol.6 No.4

분기별 안산 및 보령 석탄회에 대한 특성변화를 조사하였고 안산 석탄회에 대한 수비 선별시 산처리의 영향을 고찰하고자 하였다. 분기별 안산 및 보령 석탄회의 주결정상은 mullite와 quartz였고, 주성분은 $Al_{2}O_{3}$와 $SiO_{2}$로서 발전소 및 채취시기에 따른 큰 변화가 없었다. 반면, 입도분포는 수 $\mu\textrm{m}$에서 백 $\mu\textrm{m}$ 이상의 넓은 입도분포를 갖으며 morphology는 안산 석탄회의 경우에 큰 변화가 있었다. 따라서 석탄회는 점토의 대체원료로 사용가능하나 원ㄹ의 안정적 수급을 위해서는 반드시 선별화가 선탱되어야 한다. 안산 석탄회의 수비처리시 pH를 조절함으로서 분산성이 향상되었기 때문에 4단계에서 대부분 cenosphere를 얻을 수 있었고 입도분포도 감소하였다. 또한 4단계에서 포집된 시료의 비표면적은 비처리 석탁회보다 크게 감소한 $1.24\;m^{2}/g$이었다. Charateristics of Ansan and Boryong coal fly ashes collected at different seasons were investigated for the recycling them as ceramic raw materials. The effect of pH treatment on the classification of Ansan coal fly ashes by elutriation was discussed. Charateristics of ansan and boryong coal fly ashes were not significantly changed with power plants and seasons. major crystalline phases were mullite and quartz. These results suggested that coal fly ashes cab be used as raw materials instead of clay minerals. However, particle size distribution was very broad from a few $\mu\textrm{m}$ to over $100\;\mu\textrm{m}$. Especially, ansan coal fly ashes have various morphologies. Therefore, coal fly ashes should be classified before using as raw materials. Because of higher dispersion by pH treatment, spherical cenospheres were mainly collected in the 4th step and particle size distribusion was also decreased by elutriation for the ansan coal fly ashes. The specific surface area of the sample collected in the 4th step was $1.24\;m^{2}/g$ which was smaller than that of not treated Ansan coal fly ashes.

이동 로보트의 동역학 모델링에 의한 동적 제어 ( Dynamic Control of a Mobile Robot , Using Dynamic Model )

고기범,허화라,이장명 대한전자공학회 1997 대한전자공학회 학술대회 Vol.1997 No.1

적응 슬라이딩 모드에 의한 이동 로봇의 강인한 제어 ( Robust Control of a Mobile Robot Using Adaptive Sliding Mode )

고기범,허화라,이장명 대한전자공학회 1997 대한전자공학회 학술대회 Vol.1997 No.1

기능성 미분말의 제조공정에 관한 연구 : I. 분무건조법에 의한 microcapsule 제조

정철원,허화범,박종현,신건철 한국결정성장학회 1996 韓國結晶成長學會誌 Vol.6 No.4

분무건조법을 이용하여 무기질막 microcapsule과 무기질/유기질막 microcapsule을 제조하였다. 무기질막 microcapsule은 core 물질로 $K_{4}SO$와 clay shell 물질로 colloidal silica를 사용하였고, 무기질/유기질막 microcapsule은 core 물질로 상기 제조된 무기질막 microcapsule을 shell 물질로는 ethyl cellulose를 사용하여 각각의 microcapsule를 제조하였다. 제조된 microcapsule이 기능성을 갖기 위하여는 구형의 균일한 표면과 세공용적이 매우 중요하다. 무기질막 microcapsule인 경우 core/shell의 체적비가 0.3/0.7인 경우 구형의 균일한 표면의 microcapsule이 제조되었으며, 무기질/유기질막 microcapsule인 경우, 무게비가 0.76/0.24일 때 균일한 표면을 갖는 microcapsule이 제조되었다. 무기질/유기질막 microcapsule인 경우, 무기질막 microcapsule보다 세공용적이 감소하였고, shell물질(ethyl cellulose)의 양이 증가할수록 피복이 균일하게 되며, 세공용적도 감소하였다. Inorganic and inorganic/organic microcapsules were prepared by spray drying. $K_{4}SO$ and clay were used as the core and colloidal silica as the shell for the inoroganic microcapsules. Forthe inorganic/organic microcapsules were used the inorganic microcapsule which were mentioned above (core) and ethyl cellulose (shell). To characterize the prepared microcapsule for the practical use, the homogenity of surface and pore volume are the dominent factors. At the volume ratio of 0.3/0.7 of core/shell, the spherical and homogeneous surfaces of inorganic microcapsule could be synthesized. In the case of inorganic/organic microcapsules, the weitht ratio was 0.76/0.24. The pore volume of inorganic/organic microcapsules decreases more than that of inorganic microcapsule. The more the amount of shell (ethyl cellulose) in inorganic/organic microcapsules increases, the more the coating became homogeneous and the pore volume decreased.

화학사고의 효율적 대응을 위한 정보공유체계 개선 연구

이태형,윤정현,허화진,이율범,유병태 한국안전학회 2018 한국안전학회지 Vol.33 No.1

In this study, we developed a system for information sharing and cooperation support system among the accident response organizations to enable prompt and efficient response in responding to chemical accidents. In other words, by applying mobile messenger function, it is proposed to improve the chemical accident response system that provides information necessary for accident response promptly and accurately, and facilitates bi-directional communication between accident response organizations and field responders, thereby enabling efficient and organic response . As a result of comparing the information provision time before and after the chemical accident of chemical accident response information sharing system, the ratio of processing of substance information and chemical air diffusion information within 30 minutes was improved by 8% and 32%, respectively. As a result of this study, applying the chemical accident response information sharing system to the chemical accident response is expected to contribute to the improvement of the system and the ability to cope with the accident more effectively.

요업원료로 재활용하기 위한 석탄회의 처리 : I. 하소 및 수비의 영향

김유택,이준호,정철원,허화범,신건철 한국결정성장학회 1995 韓國結晶成長學會誌 Vol.5 No.4

석탄회를 요업원료로 재활용하기 위하여 하소 및 수비에 의하여 선별화 하였으며, 선별화의 영향을 고찰하기 위하여 비처리 석탄회와 하소 및 수비 처리한 석탄회의 결정상, morphology, 화학성분, 입도분포, 강열감량을 측정하였다. 또한, 기존의 점토 수비 실험식이 석탄회의 수비에도 적용될 수 있는지 여부를 조사하였다. 점토에 대한 수비 실험식을 석탄회의 수비에 적용한 결과 Rittinger의 실험식과 비교적 잘 일치하였다. 처리조건에 관계없이, 석탄회는 mullite와 quartz가 주결정을 이루고, 비처리 및 수비 처리한 석탄회에서는 calcite 결정이 관찰되었으나 하소한 경우 calcite의 결정 peak가 나타나지 않았다. 입자의 형태는 비처리 석탄회의 경우 cenosphere, coke type, silicate type, whisker type, aggregate type 입자로 이루어져 있고 하소한 경우에는 coke type 입자가 제거되고 상대적으로 aggregated type 입자가 많이 관찰되었다. 특히 수비 4단계의 경우에는 비교적 구형의 cenosphere가 많이 얻어졌다. 하소에 의해 입도분포가 좁아졌으며, 특히 수비에 의해서 매우 좁은 입도분포를 얻었다. Coal fly ash was calcined and elutriated for recycling as ceramic raw materials. C Crystal phases, morphologies, chemical components, particle size distributions and Ig. loss of as-received, calcined and elutriated coal fly ash were investigated to study the effects of the calci nation and elutriation on the coal fly ash classification. The experimental equations, which were used in elutriation of clay, were examined in order to find out which equation is appropriated for coal fly ash classification. It turned out that Rittinger's equation is relatively well matched for the fly ash. Having nothing to do with the treatment conditions, the crystal phases of coal f fly ash were mullite, quartz. Calcite peak was detected in as - received and elutriated coal fly a ash; however, it disappeared in calcined coal fly ash. As - received coal fly ash consists of various type of particles such as a cenosphere, coke type, silicate type, whisker type and aggregat e ed type. In case of calcined coal fly ash, coke type particles were eliminated and agglomerated type particles were relatively increased. Most of the particles that were relatively spherical cenosphere in the 4th step of elutriator. Particle size distribution was narrowed by calcination a and elutriation. Especially, in elutriation, particle size distribution was very narrow.