나노 입자 첨가에 따른 정전 멜트블로운 부직포의 여과효율에 관한 연구

장선호,심현주,Jang, Sun-Ho,Shim, Hyun-Joo 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.5

We designed a filter media which could collect of submicron size particles by applying electrostatic charge. To meet our proposed design, three different types of nano-scaled materials such as nonconductor ($SiO_2$), conductor ($Al_{2}O_{3}$), ferroelectric material ($BaTiO_3$) were incorporated into the melt-blown nonwovens made of micro fiber. Polypropylene melt-blown nonwovens, basis weights of $15\;g/m^2$ and $20\;g/m^2$, were prepared. The nano particles were diffused in the ethanol and then the electro sprayed on the nonwoven fabrics to be uniformly dispersed. The specimens containing nano particles were conditioned for three hours in the vacuum drying oven. To meet our purpose, the specimens were corona charged to develop the static electricity. The charging density and filtration efficiency of the filter media were investigated with various experimental conditions: such as types of additives and their concentrations. It was shown that the charging density and filtration efficiency were increased with increasing the basis weight of the samples. The filter media incorporated with ferroelectric particles showed the most desirable results compared with the other two additives.

실리카로 보강된 SSBR/ENR 블렌드의 물성 연구

장선호(Sun Ho Jang),리시앙수(Xiang Xu Li),리칭위안(Qingyuan Li),이담희(Dam Hee Lee),조을룡(Ur Ryong Cho) 한국고분자학회 2018 폴리머 Vol.42 No.1

실리카로 보강한 솔루션-스티렌-부타디엔 고무(SSBR)와 에폭시화 천연고무(ENR)를 다양한 조성으로 블렌드를 제조하여 조성에 따른 가교특성, 모폴로지, 인장특성, 동적점탄성 그리고 열적 특성을 조사하였다. ENR의 함량이 증가할수록 가교속도가 빨라지는 모습을 보였으며 블렌드 조성물의 경우 가교도가 증가하는 모습을 보였다. ENR의 함량이 증가함에 따라 에폭시기의 영향으로 실리카 분산성의 향상을 전자현미경(SEM)과 Payne effect를 통해 확인하였다. S75/E25, S50/E50에서는 두 개의 유리전이온도(Tg)가 나타났으며 S25/E75에서는 하나의 유리전이 온도(Tg)가 나타났고 젖은 노면의 제동 특성과 인장강도, 탄성률이 높아서 S25/E75 조성물에서 가장 상용성이 높은 것으로 판단되었다. 열적 안정성은 ENR의 함량이 증가함에 따라 초기 분해 온도가 감소함을 알 수 있었다. Solution styrene-butadiene rubber (SSBR) and epoxidized natural rubber (ENR) blends reinforced by silica had been compounded over the two-roll mill. The crosslinking characterization, morphology, tensile strength, elastic and viscos characterizations, and thermodynamic properties of blends had been investigated after processing. With the ratio of ENR increasing, the crosslinking rate and density of blends had increased. Also, the epoxy groups in blends had been also increased which will cause influence on silica dispersion and Payne effect of blends. They had been characterized by SEM and RPA. The S75/E25 blend and S50/E50 blend showed two peaks about glass transition temperature (Tg) in dynamic mechanical analysis (DMA), but the blend whose ratio was S25/E75 showed only one peak. It meant S25/E75 blend would be a good miscibility rubber material due to the larger wet grip, better tensile strength and higher elastic rate. And as for thermal stability of blends, with the ratio of ENR increased, the initial decomposition temperature of blends decreased gradually.

SBR/전분/대나무 숯 복합체의 제조와 물성

장선호(Sun Ho Jang),리시앙수(Xiang Xu Li),조을룡(Ur Ryong Cho) 한국고분자학회 2018 폴리머 Vol.42 No.1

스티렌-부타디엔 고무(SBR) 라텍스와 전분, 대나무 숯을 라텍스 블렌딩 방법으로 혼합하여 SBR/전분/대나무 숯 복합체를 제조하였다. 전분과 대나무 숯의 조성에 따라 모폴로지, 기계적 물성, 열적 특성을 조사하였다. 전분과 대나무 숯의 입자크기를 확인하였고, 전자현미경(SEM)을 이용하여 전분과 대나무 숯을 함께 사용한 경우 분산성이 향상되는 것을 확인하였다. 대나무 숯이 들어가면서 충전제-충전제, 충전제-폴리머 상호작용이 증가하는 것을 관찰하였다. 또한 대나무 숯의 함량이 증가할수록 인장강도, 탄성률, 경도의 향상이 보였으며 15 phr의 전분과 5 phr의 대나무 숯이 들어간 경우 우수한 분산성으로 인해 가장 높은 인장강도를 보였다. 열적 안정성은 대나무 숯의 함량이 증가함에 따라 초기 분해 온도가 증가하였다. Styrene-butadiene rubber (SBR) latex compounds filled with starch-bamboo charcoal powder hybrids were prepared by latex compounding method. The morphology, mechanical properties and thermodynamic properties of the SBR/starch/bamboo charcoal composites were investigated. The particle size of starch and bamboo charcoal powder was measured by particle size analyzer. SEM was used to confirm the uniform dispersion of starch-bamboo charcoal hybrids in the matrix. The results indicated that the bamboo charcoal could improve the mechanical properties (tensile strength, modulus, and hardness), filler network strength and filler-polymer interaction of compounds. The hybrid with best ratio was made from 15 phr starch and 5 phr bamboo charcoal, which has good dispersion state and great tensile strength. From the results of TGA, the initial decomposition temperature also increased gradually, with the bamboo charcoal ratio increased.

모듈형 농업로봇의 다양한 밭 노지 작업 특성 연구

장선호(Sun-Ho Jang),홍형길(Hyin-Ggil Hong),윤해룡(Hae-Yong Yun),강민수(Min-Su Kang),박관형(Kwan-hyung Park),권태희(Tae-hee Kwon),천원기(Won-Ki Chun),김대현(Dae-Hyun Kim),조용준(Yongjun-Jin Cho) 한국기계가공학회 2024 한국기계가공학회지 Vol.23 No.3

This paper addresses the challenges posed by an aging population and declining interest in agriculture, leading to a decrease in rural population and domestic agricultural competitiveness in South Korea. To bolster productivity in the face of a rising proportion of elderly farm managers and diminishing agricultural land area, the paper explores the integration of autonomous farming equipment modules with Agricultural Robots. These modules aim to enhance efficiency and performance across various crop types and cultivation methods, while their user-friendly features make them accessible to elderly and female farmers, thereby maximizing productivity. The study evaluates the modules based on stability, convenience, eco-friendliness, high efficiency, and automation. By promoting advanced technologies like autonomous control and robotic integration, this research aims to address challenges related to an aging agricultural workforce and boost overall agricultural productivity.

멜트블로운 부직포의 정전 처리조건이 여과효율에 미치는 영향

심현주,강준영,장선호,오태환,Shim, Hyun-Joo,Kang, June-Young,Jang, Sun-Ho,Oh, Tae-Hwan 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.2

The air filter media were prepared using light polypropylene melt- blown nonwovens and then, corona charge was applied to achieve with low pressure drop and high filtration efficiency air filter. The processing variables for the corona treatments were set up, such as, the electric potential distance between the electrode and the nonwoven, the number of charging, the sequences of charging surfaces, and the concentration of ferro-dielectric nano particles. The electrical potential was applied in the range of 15 to 35 kV, the number of charging was 1 to 4 times with and without turn over the charging surface, the concentration of ferro-dielectric nano particle solutions were 0.5 to 1.5% (W/V). In this research, the most probable processing conditions gave a clue to make a HEPA filter when the media was plied 5 times. This HEPA filter showed its initial pressure drop be 7.7 mmAq and filtration efficiency be 99.99%.

Silica-Starch Reinforced Styrene-Butadiene Rubber Composites

Qingyuan Li,Xiangxu Li,Sun-Ho Jang(장선호),Dam-Hee Lee(이담희),Yuan Fan,Ur Ryong Cho(조을룡) 한국고분자학회 2017 폴리머 Vol.41 No.6

Silica-starch-reinforced styrene-butadiene rubber (SBR) was prepared by a modified sol-gel method of mixing the silica sol, the starch paste, and then in situ blending the SBR latex. The fracture surface of the samples after the tensile test was characterized by FE-SEM. The tensile strength, the storage modulus, the hardness and the swelling test of the vulcanized samples were systematically discussed. The results showed the elongation at break, the hardness and the storage modulus increased with the increasing of silica in the as-prepared samples. The swelling ratio decreased with increase in the content of silica, indicative of the excellent crosslink density in the silica-starch-reinforced SBR.

Reinforcement Effects of Sulfonated Bamboo Charcoal-Chitosan (sBC-CS) Hybrid for Styrene-Butadiene Rubber Latex

Xiang Xu Li(리시앙수),Ji Hwan Oh(오지환),Shin Hye Kang(강신혜),Sun Ho Jang(장선호),Dam Hee Lee(이담희),Ur Ryong Cho(조을룡) 한국고분자학회 2017 폴리머 Vol.41 No.5

스티렌-부타디엔 고무에 4가지 충전제(키토산, 뱀부차콜 분말, 술폰화된 뱀부차콜, 술폰화된 뱀부차콜-키토산 혼성체)를 사용하여 라텍스 컴파운드법으로 고무복합체를 제조하였다. 주사전자현미경과 카본블랙 분산 테스트를 통해서 균일하게 충전제가 고무 매트릭스 내에 분산되었음을 확인하였으며, 가황된 고무복합체의 인장강도, 저장 탄성률, 내마모성, 마찰 계수, 팽윤 특성, 산소 투과도를 조사하였다. 술폰화된 뱀부차콜-키토산 혼성체가 다른 충전제보다 고무 매트릭스에 분산된 입자가 더 작고 잘 분산된 상태를 보였다. 또한 좋은 소수성 성질과 균일한 분산도로 충전제 중 가장 우수한 보강 성능을 보였다. Styrene-butadiene rubber (SBR) composites, incorporated with four kinds of fillers (chitosan, bamboo charcoal powder, sulfonated bamboo charcoal and sulfonated bamboo charcoal-chitosan hybrid) with similar filling ratio, were fabricated by a latex compounding method. Field emission scanning electron microscopy and carbon black dispersion tests were employed to confirm the uniform dispersion of filler in the matrix. The tensile strength, storage modulus, abrasion resistance, friction coefficient, swelling property, and oxygen transmission rates of the vulcanized rubber composites were investigated. The sulfonated bamboo charcoal-chitosan hybrid (sBC-CS) showed a smaller particle size and a better dispersion state compared with those of other fillers. In addition, this compound exhibited the best mechanical reinforcing performance among the four fillers with its great hydrophobic property and good dispersion rate.

Adult Still's Disease 3례

홍대식,장선호,송경일,박희숙 순천향대학교 1990 논문집 Vol.13 No.3

This is a report of three cases of adult onset Still's disease. The term adult Still's disease was first used by Bywater's in 1971. This is not common in adult but it is recognized as a causes of multiple joint pain and fever of unknown origin and it's clinical significance. Most patients reported have presented with characteristic and identical. clinical syndrome which include high fever, maculopapular rash, polyarthritis associated with leucocytosis and neutrophilia. But serologic abnormalities was not found and no etiologic agents have been identified. Diagnosis of adult onset Still's disease require exclusion of both common and rare causes of febrile polyarthritis as well as prolonged floow-up. Treatment of adult onset Still's disease is aspirin, non-steroidal antiinflammatory durg(NSAID) and steroid. Now, we report three cases of adult Still's disease.