• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.550-557
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• 2002

TiO$_2$ particles coated on fly ash composites for use in photocatalyst were synthesized by the precipitation dropping method and heated at $700^{\circ}C$ for 2 h. The pH of reaction solution, the addition rate of NH$_4$HCO$_3$, the stirring speed, the reaction temperature and the concentration of TiC1$_4$ had a pronounced effect on the nature of precipitated TiO$_2$ particles on the surface off fly ash and the crystal structure of precipitated TiO$_2$ particles. At an addition rate of NH$_4$HCO$_3$; 1.0 ml/min, the pH of the reaction solution; 6, the stirring speed; 1,000 rpm and the reaction temperature; 8$0^{\circ}C$, about 10 nm of TiO$_2$ particle size and homogeneous precipitated layer on the surface of a fly ash was achieved. On the contrary, at an addition rate of NH$_4$HCO$_3$; 0.3,0.5 ml/min, the pH of the reaction solution; 2 and 11, the stirring speed; 300~500 rpm and the reaction temperature; lower than 5$0^{\circ}C$:, Inhomogeneous precipitated layer was developed on a fly ash. TiO$_2$ particles with anatase phase was formed as-dried precipitation at the low concentration of Tic14, the high addition rate of NH$_4$HCO$_3$ and the high reaction temperature, the crystalline fraction of anatase increased with raising heat-treatment temperature and rutile phase began to formation at 80$0^{\circ}C$. The crystal size of TiO$_2$ particles increased with raising the heat-treatment temperature, the crystal size was showed about 21 m at $700^{\circ}C$. Anatase type of TiO$_2$ coated on the fly ash heated at $700^{\circ}C$ for 2 h showed 1.25 g/cm$^3$of particle density, 82.8% of strength and 69.5 Lab of whiteness and can be used as a photocatalyst.

• Proceedings of the Korea Society of Poultry Science Conference
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• 1998.04a
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• pp.51-86
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• 1998

$\bigcirc$ 재래닭 생산물의 소비 및 구매형태 등에 대한 조사에서 종합적인 결론은 최종 소비자의 응답자는 총 2,250명이었으며 연령, 성별, 직업, 거주지, 주거형태, 가족수, 소득분포등이 비교적 다양하게 분포되어 있다. 판매업소의 특성은 지역별, 매장면적, 업주연령, 성별, 경력등에서 매장위치는 약 60%가 농촌이고 관광지 21.3%, 도시 19.0%순이였으며 매장 면적은 10-30평이 66.9%, 경력은 3년이하 27.4%, 3-5년 22.7%, 5-10년 22.2%였다. $\bigcirc$ 재래닭고기의 소비형태에서 육류선호도는 쇠고기, 돼지고기, 닭고기 순이였으며 재래닭고기의 소비형태에서 전체 응답자의 64.4%가 먹어본 경험이 있었다. 주로 섭취시기는 74.5%가 여름철에 식구들과 같이 회식할 때 식사대용이나 부식용으로 섭취하였다. 소비자가 재래닭고기를 좋아하는 이유는 고기가 쫄깃쫄깃하여 씹는맛과 지방이 적으며 단백한 맛 때문에 독특해서 좋아한다고 하였으며, 싫어하는 이유는 너무 질기고 고기의 양이 너무 적다는 의견이 많았다. 선호하는 요리방법은 백숙, 삼계탕이었고 좋아하는 부위는 역시 다리부위였다. 재래닭고기의 섭취량에 대하여는 1회에 2인이 1마리를 먹는다가 36.4%, 3인이 1마리 31.8%로서 68.2%가 2-3인이 1마리를 먹는다고 하였으며, 가족구성원 중에는 가장이 제일 선호하는 것으로 나타났다. $\bigcirc$ 음식점에서 판매되는 요리한 재래닭의 1마리 가격에 대한 의견은 84.5%가 20,000원정도면 부담이 없이 먹겠다고 하였다. $\bigcirc$ 재래닭의 구입행동에서 구입주체는 주부였으며, 구입장소는 농.축협의 슈퍼와 정육점이었고 백화점과 재래닭 사육장에서 직접구입도 하고 있었다. 구입 동기는 가족들이 좋아하고 영양가를 생각한다가 62%였으며 구입정보는 주위사람의 권유로 구입하고 있었다. $\bigcirc$ 구입할 때 중점적으로 살펴보는 사항은 신선도와 순수재래종 여부, 위생상태였다. 한편 소비자가 언제나 구입할 수 없다는 의견이 85.2%나 되어 원활한 공급과 시장조성이 아직 정착되지 않고 있었다. $\bigcirc$ 현재 유통되고 있는 재래종닭은 소비자 대부분이 잡종으로 인식하고 있었으며, 재래종과 일반육계와의 구별은 깃털색, 피부색, 정강이색등 외관상으로 구별하고 있었다. 체중에 대한 반응은 너무 작다는 의견이었고, 식품으로의 인식도는 비교적 고급식품으로 인식하고 있다. $\bigcirc$ 재래종닭고기의 브랜드화에 대한 견해는 젊고 소득이 높은 계층에서 브랜드화의 필요성을 강조하고 있다. $\bigcirc$ 재래종달걀의 소비형태는 대부분의 소비자가 좋아하였으나 아직 먹어보지 못한 응답자가 많았다. 재래종달걀의 맛에 대해서는 고소하고 독특하여 차별성을 느끼고 있었다. $\bigcirc$ 재래종달걀의 구입장소는 계란판매점(축협.농협), 슈퍼, 백화점, 재래닭 사육 농장등 다양하였으며 포장단위는 10개를 가장 선호하였고, 포장재료는 종이, 플라스틱, 짚의 순으로 좋아하였다. $\bigcirc$ 달걀의 가격은 200원정도를 적정하다고 하였으며, 크기는 (평균 52g)는 가장 적당하다고 인식하고 있으며, 난각색은 대부분의 응답자가 갈색을 선호하였다. $\bigcirc$ 재래종달걀의 구입시 애로사항은 믿을수 없고, 구입장소를 몰라서, 값이 싸다 등이었고, 앞으로 신뢰할 수 있고 위생적인 생산 및 유통체계가 확립될 경우 더 많이 소비하겠다는 의견이었다. $\bigcirc$ 재래닭 판매업소(식당)의 판매형태는 66.7%인 대부분의 업소가 잡종과 개량종 유색닭을 판매하고 있었으며, 1개 업소에서 1일 판매수수는 5-10수의 영세한 판매형태였고, 계절적으로는 여름철에 대부분을 판매하였다. $\bigcirc$ 식당에서 판매하는 재래닭고기의 요리 종류는 주로 백숙이었고, 삼계탕, 닭볶음도 있었으며, 요리된 재래닭 1마리 가격은 20,000원 이상이었으며, 20,000원이하로 판매하는 잡종이 많았다. $\bigcirc$ 재래닭 판매업소에서 재래닭을 구입하는 방법은 재래닭 사육농장에서 1회에 수십마리 구입하여 판매업소의 간이 사육장에서 기르면서 판매하는 업소가 49.6%, 도계된 재래닭을 구입하여 판매하는 업소 26.9%, 직접 재래닭을 사육하면서도 도계하여 판매하는 업소가 21.7%였다. 판매업소에서의 재래닭 사육기간은 90일 이상이었으며 대부분의 업주는 야산에서 방사한 것을 좋게 생각하고 있었다.

• Korea journal of population studies
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• v.28 no.2
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• pp.1-32
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• 2005

The optimum population of a society or country can be defined as 'the population growth path that maximizes the welfare level of the society over the whole generations of both the present and the future, under the paths allowed by its endowments of production factors such as technology, capital and labor'. Thus, the optimum size or growth rate of population depends on: (i) the social welfare function, (ii) the production function, and (iii)demographic economic interrelationship which defines how the national income is disposed into consumption(birth and education of children included) and savings on the one hand and how the demographic and economic change induced thereby, in turn, affect production capacities on the other. The optimum population growth path can, then, be derived in the process of dynamic optimization of (i) under the constraints of (ii) and (iii), which will give us the optimum population growth rate defined as a function of parameters thereof. This paper estimates the optimum population growth rate of Korea by: specifying (i), (ii), and (iii) based on the recent development of economic theories, solving the dynamic optimization problem and inserting empirical estimates in Korea as the parametric values. The result shows that the optimum path of population growth in Korea is around TFR=1.81, which is affected most sensitively, in terms of the size of the partial elasticity around the optimum path, by the cost of children, share of capital income, consumption rate, time preference, population elasticity of utility function, etc. According to a survey implemented as a follow up study, there are quite a significant variations in the perceived cost of children, time preference rate, population elasticity of utility across different socio-economic classes in Korea, which implied that, compared to their counterparts, older generation and more highly educated classes prefer higher growth path for the population of Korea.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.857-862
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• 2002

Porous ceramic supports with immobilized microorganisms for the water purifier were synthesized by firing green compacts of mixed powder comprising of fly ash, bentonite and an additive of yeast powder at 800∼1,000$^{\circ}C$ for 1h and the pore and mechanical properties of specimens were investigated. The compressive strength was increased in FB (Fly Ash + Bentonite) specimens while pore properties was decreased with increasing the bentonite content and sintering temperature. The compressive strength, bulk density, apparent density, porosity, mean pore size, pore volume and specific surface area of FB specimens at 800∼1,000$^{\circ}C$ were 89.6∼128.9 kgf/$cm^2$, 1.25∼1.43, 1.61∼1.78, 27.2∼62.2%, 7.9∼25.6 ${\mu}m$, 8.9∼$22.2{\times}10^{-5}\;cm^3/g$ and 35.2∼134.3 $m^2/g$, respectively. The pore properties of FBY (FB+yeast powder) specimens were superior to that of FB specimens, however compressive strength was decreased with increasing yeast powder content. The overall properties of 9F1B1Y (9F1B+10% of yeast powder) specimens at 900$^{\circ}C$ for 1 h were 98.7 kgf/$cm^2$, 1.20, 1.67, 68.1%, 48.9 ${\mu}m$, $29.5{\times}10^{-5}\;cm^3/g$ and 152.2 $m^2/g$, respectively. In this study, it was revealed that 9F1B1Y specimen demonstrated better S. saprophyticus adherence properties n their surface pores. Consequently, the microorganisms immobilized on porous ceramic supports showed better water purifying performance with many pores and adequate strength.

• Radiation Oncology Journal
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• v.16 no.1
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• pp.63-69
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• 1998

Purpose : This study is to evaluate the efficacy of small bowel displacement system(SBDS) in post-operative pelvic radiation therapy(RT) of rectal cancer patients by measurement of small bowel volume included in the radiation fields receiving therapeutic dose. Materials and Method : Ten consecutive new rectal cancer patients referred to the department of Radiation Oncology of Samsung Medical Center in May of 1997 were included in this study. All patients were asked to drink $Castrographin^(R)$ before simulation and were laid prone for conventional simulation and CT scans with and without SBDS. The volume of opacified small bowel on CT scans, which was to be included in the radiation fields receiving therapeutic dose, was measured using Picture archiving and communication system (PACS). Results : The average small bowel volumes with and without SBDS were 176.0ml(5.2-415.6ml) and 185.1ml(54.5-434.2ml), respectively The changes of small bowel volume with SBDS compared to those without SBDS were more than $10\%$ decrease in three, less than 10% decrease in two, less than $10\%$ increase in three, and more than $10\%$ increase in two patients. Conclusion : No significant advantage of using SBDS in post-operative pelvic RT for rectal cancer patients has been shown by small bowel volume measurement using CT scan considering additional effort and time needed for simulation and treatment setup.