폴리벤즈이미다졸(PBI)은 우수한 내열성, 내화학성으로 잘 알려진 슈퍼 엔지니어링 플라스틱이다. 이러한 최상위 급의 물성을 지녔음에도 불구하고 PBI는 가 공성이 매우 떨어지기 때문에 다양한 분야의 적용에 한계를 지닌다. 기존 압축 성형을 이용한 PBI 성형물은 무게가 가벼우면서 우수한 강도 및 내열성을 나타내어 가혹한 환경을 가지는 산업분야에서 주로 사용되어 왔으나, 기체에 의한 open, closed pore의 조절, 싱크마크, 스프링백 등과 같은 압축성형 공정 자체 의 문제점 때문에 양질의 결과물을 얻기 힘들다. 본 연구에서는 이러한 문제를 해결하기 위하여 개선 된 고온 압축성형방법을 이용하여 PBI 압축성형물을 제 조하였고 고성능의 압출성형물 이상의 물성을 지니기 위하여 개질 된 카본나노 튜브와 그래핀 옥사이드를 도입하여서 기계적 강도를 높이고자 하였다. 각각의 보강제들은 초음파균질기를 통하여 고분자 용액에 골고루 분산되었고, 인장강도와 굽힘강도를 측정하기 위해 각각 ASTM규격에 맞는 압축성형 시편을 제작하였으며 UTM장비를 통해 강도 및 모듈러스를 측정하고 비교하였다.

본 연구는 Hummer’s method를 이용하여 Graphene oxide (GO)를 합성하였으며, poly acrylonitrile (PAN)과 복합화하여 나노섬유 막을 제조하였다. 접촉각 측정, SEM, FT-IR, 인장강도, DI water를 이용한 flux 실험 및 BSA rejection 실험을 실시하여 막의 특성 분석을 진행하였다. PAN/GO 0.3 나노섬유의 경우, rejection 값이 59%로 PAN/GO 복합 나노섬유 막들 중 상대적으로 우수하였다. PAN/GO 복합 나노섬유 막을 수 처리 분야에 이용하여 얻은 자료는, 폐수 속의 유기물질 함량 감소 연구에 대한 기초자료로 활용될 수 있을 것으로 기대된다.

Cu nanoparticles generated by redox reduction with Fe2+ ions and porous KIT-6 were utilized for high selectivity and permeance. When positively polarized Cu nanoparticles were generated and porous KIT-6 materials were incorporated into ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate (BMIM BF4), these membranes showed the selectivity for CO2/N2 and CO2/CH4 was largely enhanced to 16.4 and 23.4, respectively while neat BMIMBF4 was 5.0 and 4.8, respectively. Furthermore, the CO2 permeance was also enhanced to 50.7 GPU. It was thought that these enhancements of separation performance was attributed to both the facilitated transport by polarized CuNPs and the increase of diffusivity by porous materials. Therefore, highly selective and permeable membrane for CO2 separation was successfully prepared.

Carbon nanofiber (CNF) composites coated with spindle-shaped Fe2O3 nanoparticles (NPs) are fabricated by a combination of an electrospinning method and a hydrothermal method, and their morphological, structural, and chemical properties are measured by field-emission scanning electron microscopy, transmission electron microscopy, Xray diffraction, and X-ray photoelectron spectroscopy. For comparison, CNFs and spindle-shaped Fe2O3 NPs are prepared by either an electrospinning method or a hydrothermal method, respectively. Dye-sensitized solar cells (DSSCs) fabricated with the composites exhibit enhanced open circuit voltage (0.70 V), short-circuit current density (12.82 mA/cm2), fill factor (61.30%), and power conversion efficiency (5.52%) compared to those of the CNFs (0.66 V, 11.61 mA/cm2, 51.96%, and 3.97%) and spindle-shaped Fe2O3 NPs (0.67 V, 11.45 mA/cm2, 50.17%, and 3.86%). This performance improvement can be attributed to a synergistic effect of a superb catalytic reaction of spindle-shaped Fe2O3 NPs and efficient charge transfer relative to the one-dimensional nanostructure of the CNFs. Therefore, spindle-shaped Fe2O3-NPcoated CNF composites may be proposed as a potential alternative material for low-cost counter electrodes in DSSCs.

Fabrication of iron oxide/carbon nanotube composite structures for detection of ammonia gas at room temperature is reported. The iron oxide/carbon nanotube composite structures are fabricated by in situ co-arc-discharge method using a graphite source with varying numbers of iron wires inserted. The composite structures reveal higher response signals at room temperature than at high temperatures. As the number of iron wires inserted increased, the volume of carbon nanotubes and iron nanoparticles produced increased. The oxidation condition of the composite structures varied the carbon nanotube/iron oxide ratio in the structure and, consequently, the resistance of the structures and, finally, the ammonia gas sensing performance. The highest sensor performance was realized with 500 oC/2 h oxidation heat-treatment condition, in which most of the carbon nanotubes were removed from the composite and iron oxide played the main role of ammonia sensing. The response signal level was 62% at room temperature. We also found that UV irradiation enhances the sensing response with reduced recovery time.

소금은 인체에서 생리작용을 위한 필수적인 물질 중 하나로, 염화나트륨(NaCl)을 주성분으로 한다. 그러나 구성 성 분인 나트륨의 과잉 섭취는 고혈압, 뇌졸중 등 심혈관질환과 골다공증의 발생률을 증가시키는 것으로 알려져, 건강유 지 및 삶의 질 향상을 위하여 나트륨 저감화를 위한 연구가 진행되고 있다. 따라서 본 연구에서는 운반체의 역할을 할 수 있는 maltodextrin을 NaCl에 적용하여 제조한 NaCl-maltodextrin 복합체를 쌀튀기의 시즈닝에 적용하여 짠맛의 증진 효과 및 나트륨 저감화 효과를 확인하고자 수행되었다. NaCl와 maltodextrin을 2:1(w/w)로 혼합한 후, 이의 20%의 수용액을 분무건조하여 NaCl-maltodextrin 복합체를 제조하였다. 분무건조 시 inlet temperature (130-170℃)와 atomizing pressure (6-22 × 10 kPa)를 각각 다르게 적용하였으며, 이 때 blower는 0.6 m 3 /min이었다. 제조한 NaCl-maltodextrin 복 합체의 외관 관찰 및 주사형 전자 현미경을 사용하여 하여 NaCl-maltodextrin 복합체 입자의 크기를 측정하였다. 또한 로터리쿠커를 사용하여 복합체를 양념한 쌀튀기를 제조하였고, 관능검사를 진행하여 NaCl-maltodextrin 복합체의 짠맛 의 저감화 효과를 확인하고자 하였다. NaCl-maltodextrin 복합체의 입자 크기 측정 결과, 분무건조 시의 inlet temperature 에 따른 차이는 나타나지 않았으나, atomizing pressure가 높아질수록 입자의 크기가 감소하였다. 양념한 쌀튀기의 관 능검사 결과 160℃의 inlet temperature와 22 × 10의 kPa atomizing pressure의 조건으로 제조한 NaCl-maltodextrin 복합체 로 양념한 시료의 짠맛이 가장 강한 것을 확인하였다. 가장 작은 NaCl-maltodextrin 복합체 입자 크기가 가장 강한 짠 맛을 나타냄에 따라 NaCl-maltodextrin 복합체가 혀와 접촉할 수 있는 표면적이 증가한 것에 기인한 것으로 판단된다. 이에 따라, 분무건조를 이용하여 제조한 NaCl-maltodextrin 복합체의 짠맛 증진 효과를 확인하였으며, 입자의 크기가 작을수록 더욱 효과적일 것으로 기대되었다.

The organic binder-free paste for dye-sensitized solar cell (DSSC) has been investigated using peroxo titanium complex. The crystal structure of TiO2 nanoparticles, morphology of TiO2 film and electrical properties are analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectra (EIS), and solar simulator. The synthesized TiO2 nanopowders by the peroxo titanium complex at 150, 300, 400˚C, and 450˚C have anatase phase and average crystal sizes are calculated to be 4.2, 13.7, 16.9, and 20.9 nm, respectively. The DSSC prepared by the peroxo titanium complex binder have higher Voc and lower Jsc values than that of the organic binder. It can be attributed to improvement of sintering properties of TCO/TiO2 and TiO2/TiO2 interface and to formation of agglomerate by the nanoparticles. As a result, we have investigated the organic binder-free paste and 3.178% conversion efficiency of the DSSC at 450˚C.

In order to know the characteristic roles of salivary protein complex (SPC) the gel-filtration chromatography was performed using the unstimulated and the stimulated whole saliva separately. The first and second dominant SPC peaks were fractionated and analyzed by immunoprecipitation HPLC (IP-HPLC) using antibodies against the essential salivary proteins including α-amylase, mucin-1, proline rich proteins (PRPs), histatin, cystatin, LL-37, lysozyme, lactoferrin, -defensin-1, -2, -3, IgA, transglutaminase 4 (TGase 4), mucocidin, α1-antitrypsin, cathepsin G. In the gel-filtration chromatography the stimulated whole saliva showed much reduced amount of SPCs than the unstimulated whole saliva, but the proportional patterns of both whole saliva were almost similar each other. Through IP-HPLC analysis both of the first and second dominant SPCs were variably positive for the essential salivary proteins, however, α-amylase, mucin-1, PRPs, lysozyme, and cathepsin G were predominant in the first dominant SPC, while cystatin, lactoferrin, β-defensin-1, -2,-3, IgA, mucocidin, TGase 4, and α1-antitrypsin were predominant in the second dominant SPC. And more, the α1-antitrypsin and cathepsin G which were mostly derived from gingival crevicular fluid were also consistently found in the SPCs. These data may suggest that the first dominant SPC, rich in α-amylase, mucin-1, PRPs, lysozyme, and cathepsin G, may play a role in food digestion, protein degradation, and mucosa lubrication, while the second dominant SPC, rich in cystatin, lactoferrin, β-defensin-1, -2, -3, mucocidin, IgA, TGase 4, and α1-antitrypsin, may play a role in the mucosa protection and antimicrobial defense.

The repair of manhole raise has been caused much construction times and disruption of traffic flow, serious environmental pollution from crushed construction wastes, and budget waste due to the repeated repair construction works. In order to overcome such problems, we have developed the new manhole repairing composite structures by using a glass fiber-reinforced polymer (GFRP) pipe, which can raise manhole to the regular height of the overlayed road pavement with rapid construction and minimum traffic jams. This environmental-friendly technology is method completed by the methyl methacrylate monomer (MMA) double wide flanged GFRP pipe composite structures in order to raise manhole to the regular height. In this paper, two kinds of the compressive strength tests of MMA mortar composites were conducted and evaluated by a general compressive strength test, and compressive strength test after freezing-thawing resistance test. It was found that this MMA mortar composites will be used for the application of the double wide flanged GFRP pipe composite structures.

It should be noted that the use of the lathe scrap for making fiber reinforced cementitious composites(FRCCs) raised friendly environmental effect as well as economy because the lathe scrap is a by-product of steel manufactures and is occurred when lathe and milling works of them are conducted to process steel manufactures. Thus, the purpose of this research is to investigate the effect of measurements of lathe scrap on the characteristics of FRCCs. For this purpose, various lathe scraps were collected from processing plants of metal, and then these were processed 10mm, 20mm, and 40mm in lengths for 2mm and 4mm in widths, respectively. FRCCs containing lathe scraps were made according to their widths and lengths, and then characteristics such as the workability, compressive strength, and flexural strength of those were evaluated. As a result, it was observed from the test results that the optimum measurements of the lathe scrap for manufacturing FRCCs was 2mm in width and 40mm in length.

To fabricate porous SiC-Si composites for heating element applications, both SiC powders and Si powders were mixed and sintered together. The properties of the sintered SiC-Si body were investigated as a function of SiC particle size and/or Si particle contents from 10 wt% to 40 wt%, respectively. Porous SiC-Si composites were fabricated by Si bonded reaction at a sintering temperature of 1650 oC for 80 min. The microstructure and phase analysis of SiC-Si composites that depend on Si particle contents were characterized using scanning electron microscope and X-ray diffraction. The electrical resistivity of SiC-Si composites was also evaluated using a 4-point probe resistivity method. The electrical resistivity of the sintered SiC-Si body sharply decreased as the amount of Si addition increased. We found that the electrical resistivity of porous SiC-Si composites is closely related to the amount of Si added and at least 20 wt% Si are needed in order to apply the SiCSi composites to the heating element.

WS2-W-WC embedded carbon nanofiber composites were fabricated by using electrospinning method for use in high-performance supercapacitors. In order to obtain optimum electrochemical properties for supercapacitors, WS2 nanoparticles were used as precursors and the amounts of WS2 precursors were controlled to 4 wt% (sample A) and 8 wt% (sample B). The morphological, structural, and chemical properties of all samples were investigated by means of field emission photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. These results demonstrated that the embedded phases of samples A and B were changed from WS2 to WS2-W-WC through carbothermal reaction during carbonization process. In particular, sample B presented high specific capacitance (~119.7 F/g at 5 mV/s), good high-rate capacitance (~60.5%), and superb cycleability. The enhanced electrochemical properties of sample B were explained by the synergistic effect of the using 1-D structure supports, increase of specific surface area, and improved conductivity from formation of W and WC phases.

Shear wall systems behave as individual wall because of openings like window and elevator cage. When coupling beams are installed in shear walls, they will have high strength and stiffness so that be less damaged by lateral loads like earthquake. However, coupling beam is difficult construction method. And arranging reinforcement of slender coupling beams are especially hard. It is because the details of coupling beam provided by ACI 318 are complex. In this paper, experiments were conducted using coupling beams with 3.5 aspect ratio to improve the details of slender coupling beams provided by ACI 318. Two specimens were proposed for this study. One specimen applied with bundled diagonally reinforcement only. Another specimen applied both bundled diagonally reinforcement and High-Performance Fiber Reinforced Cementitious Composite (HPFRCC) so that coupling beams have half of transverse reinforcement. All specimen were compared with a coupling beam designed according to ACI 318 and were evaluated with hysteretic behaviors. Test results showed that the performance of two specimen suggested in this study were similar to that of coupling beam designed according to current criteria. And it was considered that simplification of the details of reinforcement would be available if transverse reinforcement was reduced by using bundled diagonally reinforcement and HPFRCC.

Salivary proteins include numerous functional proteins which play important roles not only for the food-intake but also for the protective and defensive mechanisms. In the present study the compositions of salivary proteins were analyzed by different methods, including electrophoresis and high performance liquid chromatography (HPLC). In hydrophobic protein HPLC analysis the parotid saliva gradually produced macromolecular complexes when agitated in refrigerator until 30 minutes. These salivary protein complexes were digested by neuraminidase, and then migrated more rapidly in native tris glycine gel than the control. Therefore, it was assumed that the glycosylated proteins of parotid saliva became gradually aggregated to form salivary protein complexes similar to those of whole saliva. The salivary protein complexes were easily degenerated in different experimental buffers, i.e., SDS buffer, tris glycine buffer, methanol, etc., and resulted non-specific patterns in electrophoresis and HPLC. Therefore, it was presumed that the salivary protein complexes was made by the hydrophobic interaction as well as electrostatic attraction between salivary proteins. These data indicated that to know the real pattern of salivary protein complexes in vivo the whole saliva should be analyzed by HPLC using non-adhering column with isoelectric buffer. Consequently, the whole saliva was analyzed by HPLC using reverse phase SuperoseTM column with 20 mM potassium phosphate buffer, and two prominent peaks of salivary protein complexes were consistently found in every people. These salivary protein complex peaks were relatively stable up to 6 hours after saliva collection when the whole saliva was kept in refrigerator during experiment. Therefore, it is suggested that the salivary protein complex patterns are characteristic macromolecular structures of whole saliva, which are also applicable as a diagnostic point in different saliva-associated diseases