본 연구에서는 수용성 접착제 가장 큰 단점인 내수성을 향상시킬 수 있는 수용성 첨가제를 개발하였다. 수 용성 첨가제는 diisocyanate 그룹을 가지는 분자들을 아황산수소나트륨과 반응시켜 얻을 수 있었다. FT-IR 측정 결 과 isocyanate 그룹이 완전히 사라진 것을 볼 수 있었고, DSC의 측정결과는 150℃ 이상의 온도에서 아황산수소나트 륨이 제거되어 isocyanate를 재형성하는 것을 확인할 수 있었다. 개발된 수용성 첨가제를 본사 제품인 DM-95 접착제 에 0.5 wt% 첨가하였을 때 높은 접착성능 및 향상된 내수성을 확보할 수 있었다. 그뿐만 아니라 기존의 복잡한 접착 공정을 요구하는 2 액형 시스템에서 탈피하여 생산 공정이 간단한 1 액형 시스템을 구축할 수 있으므로 산업 전반에 서 유용하게 사용될 것으로 사료된다.

Al/expanded graphite was successfully synthesized through a facile method including ultrasonic and heat treatment. In the well-designed three dimensional structure, expanded graphite(EG) works as a conductive matrix to support coated Al particles. The effects of the fabrication parameters on the microstructures and thermal conductivities of these composites were investigated. As a result, it was found that composites with graphite volume fraction of 17.4-69.4% sintered at 600 oC/45 MPa exhibit in-plane thermal conductivities of 380-940 W/mK, over 90 % of the predictions by rule of mixture. According to the non-destructive analysis results, the synergistic enhancement was caused by the formation of efficient thermally conductive pathways due to the hybrid of the differently sized EG. The structure integrates the advantages of expanded graphite as a conductive support, preserving the electrode activity and integrity and improving the electrochemical performance.

Selective laser melting (SLM) can produce a layer of a metal powder and then fabricate a three-dimensional structure by a layer-by-layer method. Each layer consists of several lines of molten metal. Laser parameters and thermal properties of the materials affect the geometric characteristics of the melt pool such as its height, depth, and width. The geometrical characteristics of the melt pool are determined herein by optical microscopy and three-dimensional bulk structures are fabricated to investigate the relationship between them. Powders of the commercially available Fe-based tool steel AISI H13 and Ni-based superalloy Inconel 738LC are used to investigate the effect of material properties. Only the scan speed is controlled to change the laser parameters. The laser power and hatch space are maintained throughout the study. Laser of a higher energy density is seen to melt a wider and deeper range of powder and substrate; however, it does not correspond with the most highly densified three-dimensional structure. H13 shows the highest density at a laser scan speed of 200 mm/s whereas Inconel 738LC shows the highest density at 600 mm/s.

폴리술폰 고분자는 비대칭 정밀여과 멤브레인 제조에 가장 널리 사용되는 고분자 소재이다. 폴리술폰 멤브레인은 소수성 특성으로 인하여 공정상에서 빠른 막오염이 일어난다. 고분자 블렌딩은 폴리술폰 멤브레인의 수명을 향상시키는데 있어 가장 간단하고 효과적인 방법이다. sPES는 폴리술폰 블렌딩 방법을 통하여 소수성을 해결할 수 있는 유용한 친수성 고분자이다. 본 연구에서는 PSF/sPES/DMF/PVP/BE 고분자 용액을 물에 침지시켜 정밀여과 멤브레인을 제조하였다. 캐스팅 용액에 소량의 sPES 첨가함으로써 정밀여과 멤브레인 구조 변화를 볼 수 있었다. sPES의 첨가는 높은 비대칭성과 활성층의 성장, 그리고 평균 기공 크기의 감소를 가져왔다. 하지만 수투과량은 PSF/sPES/DMF/PVP/BE로 만든 멤브레인이 PSF/DMF/PVP/BE로 만든 멤브레인에 비해 더 큰 값을 보였다.

정밀여과막 제조에 있어 폴리술폰 고분자 용액에 술폰산기를 가지는 폴리술폰(s-PSF)의 첨가가 분리막의 구조 및 투과 특성에 미치는 영향을 조사하였다. 정밀여과 고분자 분리막은 폴리술폰/아프로틱 용매계/폴리비닐피롤리돈/2-부톡시에탄올을 함유하는 고분자 용액을 이용하여 캐스팅 한 후 물에 침지하여 제조하였다. 캐스팅 공정은 증기유도 상전이와 용매-비용매 상전이 공정 시간을 조정하여 비대칭 구조가 발달된 정밀 여과막을 얻을 수 있었다. DMF 단일용매와 NMP/DMAc 혼합용매계 두 가지 용매 조건에 대한 제막 결과를 비교하여 살펴보았다. 비대칭성이 나타나며 유량 향상을 보인 용매는 DMF 단일용매로 s-PSF 함량 1.53wt%이었으며 14,475(L/m²hr)의 유량과 0.246㎛의 평균기공을 나타내었다.

Recently, additive-free sweet potato has been commercialized as a healthier snack food. However, these products are producing by semi-dried form to extend shelf-life, hence the products also possesses hard texture during chewing. To produce crispy sweet potato snack, this study was attempted to dry the semi-dried sweet potato instantly by a hot-press (HP) process. Mashed sweet potato was reformed and semi-dried at 65°C for varying time to provide various final moisture contents. The semi-dried samples were subjected to HP at the process temperature of 175-180°C for 2 seconds. As quality parameters, moisture content, brix, color, texture and sensorial test of the products were evaluated. Based on the results, optimal quality of the product was obtained by the semi-dried sample with 15~18% moisture at which the products exhibited good crispiness with bright yellow color. When the moisture content of the sample before HP was lower than 15%, the final products were normally broken during the HP process. In addition, extreme browning appearance was generated in this condition. Conversely, the sample with more than 18% of moisture was not completely dried by HP and the final product did not possess the crispy texture, although this product showed bright yellow appearance. Consequently, this study demonstrated the potential application of HP in sweet potato processing and the best condition was greatly affected by moisture content of sample prior to HP process.

This research aims to analyze the potential possibility of the butyl ether (BE, oxygenates of di-ether group) as a fuel additives for a naturally aspirated direct injection diesel engine fuel. Compared with the diesel fuel, smoke emission decreased approximately 26% by applying the blended fuel(diesel fuel 80 vol-% + BE 20vol-%) at the engine speed of 2,500 rpm and with full engine load. There was none significant difference between the blended fuel and the diesel fuel on the power, torque, and brake specific energy consumption rate of the diesel engine. But, NOx emission from the blended fuel was higher than that of the commercial diesel fuel. As a counter plan, the EGR method was employed to reduce the NOx. We found the possible area where the simultaneous reduction of the smoke and the NOx emission from the diesel engine was achieved by applying the BE blended fuel and the cooled EGR method.

In this study, we intensively investigated the effect of conductive additive amount on electrochemical performance of organic supercapacitors. For this purpose, we assembled coin-type organic supercapacitor cells with a variation of conductive additive(carbon black) amount; carbon aerogel and polyvinylidene fluoride were employed as active material and binder, respectively. Carbon aerogel, which is a highly mesoporous and ultralight material, was prepared via pyrolysis of resorcinolformaldehyde gels synthesized from polycondensation of two starting materials using sodium carbonate as the base catalyst. Successful formation of carbon aerogel was well confirmed by Fourier-transform infrared spectroscopy and N2 adsorptiondesorption analysis. Electrochemical performances of the assembled organic supercapacitor cells were evaluated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements. Amount of conductive additive was found to strongly affect the charge transfer resistance of the supercapacitor electrodes, leading to a different optimal amount of conductive additive in organic supercapacitor electrodes depending on the applied charge-discharge rate. A high-rate charge-discharge process required a relatively high amount of conductive additive. Through this work, we came to conclude that determining the optimal amount of conductive additive in developing an efficient organic supercapacitor should include a significant consideration of supercapacitor end use, especially the rate employed for the charge-discharge process.

OBJECTIVES: The objective of this research is to develop additives for the modification of Solvent DeAsphalting Residue (SDAR) to be used as pavement materials, and evaluate the performance of asphalt mixture manufactured using the SDAR modified by developed additives. METHODS: The SDAR generally consists of more asphaltenes and less oil components compared to the conventional asphalt binder, and hence, the chemical/physical properties of SDAR are different from that of conventional asphalt binder. In this research, the additives are developed using the low molecular oil-based plasticizer to improve the properties of SDAR. First, the chemical property of two SDARs is analyzed using SARA (saturate, aromatic, resin, and asphaltene) method. The physical/rheological properties of SDARs and SDARs containing additives are also evaluated based on PG-grade method and dynamic shear-modulus master curve. Second, various laboratory tests are conducted for the asphalt mixture manufactured using the SDAR modified with additives. The laboratory tests conducted in this study include the mix design, compactibility analysis, indirect tensile test for moisture susceptibility, dynamic modulus test for rheological property, wheeltracking test for rutting performance, and direct tension fatigue test for cracking performance. RESULTS : The PG-grade of SDARs is higher than PG 76 in high temperature grades and immeasurable in low temperature grades. The dynamic shear modulus of SDARs is much higher than that of conventional asphalt, but the modified SDARs with additives show similar modulus compared to that of conventional asphalt. The moisture susceptibility of asphalt mixture with modified SDARs is good if, the antistripping agent is included. The performance (dynamic modulus, rutting resistance, and fatigue resistance) of asphalt mixture with modified SDARs is comparable to that of conventional asphalt mixture when appropriate amount of additives is added. CONCLUSIONS: The saturate component of SDARs is much less than that of conventional asphalt, and hence, it is too hard and brittle to be used as pavement materials. However, the modified SDARs with developed additives show comparable or better rheological/physical properties compared to that of conventional asphalt depending on the type of SDAR and the amount of additives used.

PEBAX는 높은 CO2 선택도로 인하여 CO2 포집을 위한 분리막 연구에 널리 사용하고 있다. 본 연구에서는 Poly(ether block amides) (PEBAX) 2533을 에탄올에 용해, support를 PAN(Polyacrylonitrile), PSf(Polysulfone)로 사용하여 복합평 막을 제조하였다. 투과선택도를 향상시키기 위하여 Poly (ethylene glycol) (PEG) 를 첨가하여 막을 제조한 후 CO2, 와 N2 기체에 대한 투과도와 선택도를 평가 하였다. PEG도입에 의한 PEBAX 복합막 제조는 PEBAX가 가지고 있는 투과도 한계를 향상 시킬 수 있다.

대기오염에 관한 관심은 국내·외에서 점진적으로 상승하고 있으며, 자동차와 연료분야 연구자 들은 청정 (친환경 대체연료) 연료와 연료품질 향상 등을 이용하여 새로운 엔진 설계, 혁신적인 후 처리 시스템 등의 많은 방법으로 차량 배기가스를 감소시키려고 노력하고 있다. 이러한 연구들은 주로 배출 가스 및 가솔린 차량의 PM 입자 배출 두 가지 이슈로 진행되고 있다. 자동차의 배출가스 및 미규제 물 질, PM (입자상 물질) 입자는 환경오염과 인체에 악영향을 주는 많은 문제를 일으키고 있다. 자동차 배 출가스의 주요 물질인 입자상 물질은 작은 입자로 구성된다. 이러한 작은 크기 때문에, 흡입된 입자는 쉽게 폐 깊숙이 침투 할 수 있다. 이 입자의 거친 표면들은 대기중에서 다른 독성 물질과 결합하기가 쉽다. 따라서 입자흡입의 위험을 증가시킨다. 함산소 연료첨가제 유형 (MTBE, 바이오 ETBE, 바이오 에 탄올, 바이오 부탄올)에 기초하여, 본 논문은 가솔린 자동차 배출가스 및 미규제 물질, 나노입자 배출에 산소함량의 영향을 토론하였다. 또한, 본 논문은 두 가지 시험모드를 사용하여 배출가스 특성을 평가하 였다. 시험모드는 FTP-75 및 HWFET 모드이었다.전체 측정항목에서 배출가스 규제 값보다 적게 배출되고 있는 것을 볼 수 있었고, 산소함량이 증가하 면서 측정항목에 따라 증감이 다름을 알 수 있었다.

Additive manufacturing (AM) is defined as the manufacture of three-dimensional tangible products by additively consolidating two-dimensional patterns layer by layer. In this review, we introduce four fundamental conceptual pillars that support AM technology: the bottom-up manufacturing factor, computer-aided manufacturing factor, distributed manufacturing factor, and eliminated manufacturing factor. All the conceptual factors work together; however, business strategy and technology optimization will vary according to the main factor that we emphasize. In parallel to the manufacturing paradigm shift toward mass personalization, manufacturing industrial ecology evolves to achieve competitiveness in economics of scope. AM technology is indeed a potent candidate manufacturing technology for satisfying volatile and customized markets. From the viewpoint of the innovation technology adoption cycle, various pros and cons of AM technology themselves prove that it is an innovative technology, in particular a disruptive innovation in manufacturing technology, as powder technology was when ingot metallurgy was dominant. Chasms related to the AM technology adoption cycle and efforts to cross the chasms are considered.

대기오염에 관한 관심은 국내·외에서 점진적으로 상승하고 있으며, 자동차와 연료 연구자들은 청정(친환경 대체연료) 연료와 연료품질 향상 등을 이용하여 새로운 엔진 설계, 혁신적인 후 처리 시스 템 등의 많은 접근을 통하여 차량 유해 배기가스를 감소시키려고 노력하고 있다. 이러한 연구들은 가솔 린 자동차의 배출가스 및 가솔린 차량의 PM 입자 배출 등의 두 가지 이슈로 진행되고 있다. 자동차의 배출가스 및 PM(입자상 물질) 입자는 환경오염과 인체에 악영향을 주는 많은 문제를 일으키고 있다. 추 가로, 함산소 첨가제로서 연료에 포함된 MTBE (Methyl Tertiary Butyl Ether)에 대한 환경 문제점을 연 구하고 있다. 연구자들은 MTBE가 건강에 미치는 영향에 대한 많은 데이터를 가지고 있다. 이러한 데이 터는 높은 MTBE 용량에서 잠재적인 발암 물질 임을 결론짓고 있다. 함산소 연료첨가제 유형 (MTBE, 바이오 ETBE, 바이오 에탄올, 바이오 부탄올)에 기초하여, 본 논문 은 가솔린 연료 물성 및 증발가스 배출 특성에 대해 산소함량의 영향을 검토하였다. 또한, 연료물성에 대한 휘발유 차량의 가속 및 출력 성능을 평가하였다.

This study was carried out to investigated optimum additive ratio of barley flour for substitution of rice bran atcultivation of winter mushrooms. Mycerial growth was faster according to increase of barley flour ratio than those of controls, butonly some slow at the addition of 10% barley flour. Yields of fruiting body show the highest to 165.4g/850ml of medium whichare the addition 30% of barley flour and not significant difference of yields up to the addition of 70% barley flour. Diameter ofpileus was the highest at the addition of 30% barley flour. Hardness of pileus and stipes were the highest at the addition of 10%barley flour. The L value of stipes were the hight at the addition of barley flour, but the L value of pileus were decreased at theaddition of barley flour, but there was no significant difference in the a-value and the b-value.