• 한국재료학회지
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• 제13권11호
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• pp.749-755
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• 2003

A development of micropores of $CO_2$activated isotropic carbon fibers from TEM was observed. It was observed that the micropores of activated carbon fibers(ACFs) were consisted of slit-shaped pores(SP) and cylinder-shaped pores(CP). The SPs were formed between two parallel-carbon layers, and the CPs were formed at a place which is connected polygonally by more than two carbon layers. It was shown that the CPs of the ACFs were developed at high degree of burn-offs and at high activation temperature. The pore size distribution of the best ACF, which was observed at a highest value of specific surface area(3,495 $\m^2$/g), showed a continuous distribution in the range of about $4∼l5\AA$, and the median pore size was 6.7$\AA$. The super-high specific surface area of ACFs was found to be due to that the SPs were connected with a maximum size of 7∼8$\AA$ continuously, It is possible that the SPs should be formed in the ACFs in order to show super-high SSA.

• 한국식품과학회지
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• 제10권2호
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• pp.143-150
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• 1978

저자들은 전보(Korean J. Food Sci. Techno., 9,123(1997)에서 분리 대두 단백의 식품학적 성질을 조사하였다. 본 연구에서는 이 성질을 응용하여 대두 단백섬유를 제조하고저 분실 험실에서 고안 설계하여 의뢰제작한 protein spinning apparatus를 사용하여 분리 대두단백으로 대두단백섬유 제조실험을 행한결과 texture가 우수한 제품을 얻었다. 제조조건은 15-18% 단백질용액을 알카리 (0.6%)로 처리하여 50-100 PSI spinning press로 사출한 후 12% Nacl-1 N acetic acid bath에서 응고시켰다. 12% 단백질 용액은 생성된 단백섬유의 texture가 불량하여 일정한 모형을 유지하지 못하였다. 제품의 성질을 Instron기기와 texturometer를 사용하여 측정하였다. 아울러 대두 단백섬유의 형성기작을 제시하였다.

• 보존과학연구
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• 통권29호
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• pp.5-18
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• 2008

Hanji among paper, which is material for support of the organic artifact such as painting and Thangkas, is given as much importance as the original material in the conservation treatment of artifacts. This lining paper can go through physical and chemical deterioration due to its organic nature, and inflict serious damage to the original materials of the artifact. There is a lot of difficulty in keeping continuous production of the paper mulberry fiber based on lining paper due to a short supply of raw material and discontinuation of traditional method. Also restoration and conservation treatment is done by relying only on the knowledge and skill of few experts without any recognized manual based on scientific analysis. In this study, we evaluated the stability of lining paper which is used to support organic artifact. As the result of experiments, this lining paper was made from mulberry tree in Korea and produced by means of oebal method, but was not treated by starch in its surface.

• 한국환경과학회지
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• 제23권6호
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• pp.1165-1173
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• 2014

For the field application of dielectric barrier discharge plasma reactor in nutrient solution culture, a filtration-DBD (dielectric barrier discharge) plasma reactor was investigated for the Ralstonia solanacearum which causes bacterial wilt in aquiculture. The filtration-DBD plasma reactor system of this study was consisted of filter, plasma reactor, reservoir. The DBD plasma reactor consisted of a quartz dielectric tube, discharge electrode (inner) and ground electrode (outer). The experimental results showed that the inactivation of R. solanacearum with filter media type in filter reactor ranked in the following order: anthracite > fiber ball > sand > ceramic ball > quartz ceramic. In filtration + plasma process, disinfection effect with the voltage was found to small. In disinfection time of 120 minutes, residual R. solanacearum concentration was 1.17 log (15 CFU/mL). When the continuous disinfection time was 120 minute, disinfection effect was thought to keep the four days. In sporadic operation mode of 30 minutes disinfection - 24 hours break, residual R. solanacearum concentration after five days was 0.3 log (2 CFU/mL). It is considered that most of R. solanacearum has been inactivated substantially.

• Carbon letters
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• 제9권2호
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• pp.108-114
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• 2008

We have demonstrated the feasibility of using electrospinning method to fabricate long and continuous composite nanofiber sheets of polyacrylonitrile (PAN) incorporated with zinc oxide (ZnO). Such PAN/ZnO composite nanofiber sheets represent an important step toward utilizing carbon nanofibers (CNFs) as materials to achieve remarkably enhanced physico-chemical properties. In an attempt to derive these advantages, we have used a variety of techniques such as field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high resolution X-ray diffraction (HR-XRD) to obtain quantitative data on the materials. The CNFs produced are in the diameter range of 100 to 350 nm after carbonization at $1000^{\circ}C$. Electrical conductivity of the random CNFs was increased by increasing the concentration of ZnO. A dramatic improvement in porosity and specific surface area of the CNFs was a clear evidence of the novelty of the method used. This study indicated that the optimal ZnO concentration of 3 wt% is enough to produce CNFs having enhanced electrical and physico-chemical properties.

• 한국군사과학기술학회지
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• 제1권1호
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• pp.114-127
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• 1998

A user friendly computer code(EMCOMST; Electro-Magnetic response for COMposite STructures) was developed which provides with computations of the response characteristics such as reflectance and transmittance to the incident wave angles, frequencies, composite thicknesses, ply orientations, and types of backplate as the linearly polarized transverse electro-magnetic wave is emitted to the advanced composite structures. In this investigation were reviewed the electromagnetic characteristics of the continuous orthotropic fiber-reinforced organic matrix composites with or without ferrite fillers, which are actively applied to low-weight and high-strength aircraft structures. Also were calculated the response of the three layered compound structures which have appropriately stacked above-mentioned materials as transmitting layer, absorbing layer, reflection layer, respectively under the specific thickness constraints for mechanical strength design requirements. For the composite structures presented in this study, minimum reflectance value less than -5㏈ can be obtained in the frequency range of 4 to 12 ㎓. In addition, analysis of structures attached isotropic radar absorbing materials(RAM) is facilitated by putting the material properties in the material input card entries adequately.

• Carbon letters
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• 제5권4호
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• pp.159-163
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• 2004

The polymer-ceramic hybrid, known as 'ceramer', was synthesized by a sol-gel process by incorporating different amount of alkoxide as source of silicon in resorcinol-formaldehyde in presence of basic catalyst to get different percentage of silicon in ultimate carbonized composites. FTIR of the ceramer confirms that it is a network of Si-O-Si, Si-O-$CH_2$ and Si-OH type groups linked with benzene ring. Different amount of silicon in the ceramer exhibits varying temperature of thermal stability and lower coefficient of thermal expansion as compared to pure resorcinol-formaldehyde resin. The lower value of CTE in ceramer is due to existence of silica and resorcinol -formaldehyde in co-continuous phase. Unidirectional composites prepared with ceramer matrix and high-strength carbon fibers show lower value of flexural strength at polymer stage as compared to those prepared with resorcinol-formaldehyde resin. However, after heat treatment to $1450^{\circ}C$, the ceramer matrix composites show large improvement in the mechanical properties, i.e. with 7% silicon in the ceramer, the flexural strength is enhanced by 100% and flexural modulus value by 40% as compared to that of pure resorcinol-formaldehyde resin matrix composites.

• 한국세라믹학회지
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• 제47권6호
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• pp.485-490
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• 2010

In our previous studies, continuous SiC fiber-reinforced SiC-matrix composites ($SiC_f$/SiC) had been fabricated by two different slurry infiltration methods: vacuum infiltration and electrophoretic deposition (EPD). 12 wt% of $Al_2O_3-Y_2O_3$-MgO with respect to SiC powder was used as additives for liquid-phase assisted sintering. After hot pressing at $1750^{\circ}C$ under 20 MPa for 2 h in Ar atmosphere, a high composite density could be achieved for both cases, whereas the problems such as large grain size and non-uniform distribution of liquid phase were observed, which was resulted in the relatively poor mechanical properties of composites. Therefore, efforts have been made to reduce the grain growth during the sintering, including the optimization for hot pressing condition and utilization of spark plasma sintering using a SiC monolith. Based on the results, spark plasma sintering was found to be effective method in decreasing the amount of sintering additive, time and grain growth, which will be explained in comparison to the results of hot pressing in this paper.

• Composites Research
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• 제17권6호
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• pp.1-7
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• 2004

입자강화복합재료에 관한 연구는 오래 전부터 수행되어왔다. 최근 활발한 연구가 이루어지고 있는 나노복합재료도 역시 입자강화복합재료의 한 종류라 할 수 있다. 본 연구에서는 섬유강화 복합재료의 모재로서 사용되어질 수 있는 다중벽탄소나노튜브/에폭시 복합재료를 제작하고 그 물성을 고찰하였다. 본 연구에서 정립한 제작 공정을 사용하여 제작 된 다중벽 탄소나노튜브/에폭시 복합재료의 인장 물성을 MWNT의 첨가량에 따라 고찰하였다 0.5wt%의 MWNT를 첨가 하였을 때, 인장강성은 19%, 인장강토에서는 12%의 증가를 보였다. 또한 경화시 발생하는 재응집 현상을 관찰하고, 기계적 물성을 더 높이 항상시키기 위해서는 이 현상을 억제해야 함을 확인하였다.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1042-1047
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• 2003

The goal of this research is to implement a PC-based remote control system of ion implanter using Visual Basic programming. Presently, skilled process engineers are required to regularly setup and adjust implanter parameters. Any reduction in the number of production hours devoted to ion beam implanter setup or recalibration after a species change would represent substantial improvements in both manpower and equipment utilization. An optical communication system for the remote control and telemetry in the operation of the 50kev potential was designed and constructed. This system enables continuous and safe operation of the ion implanter and can be the basis for the automation. The isolation characteristics of optical fiber were 10kV/cm, and performance tests of the system under the intense noise environment during the implanter operations showed satisfactory results. This system is designed to completely replace the existing human-machine interface with many new functions. This paper describes the important components of the system including system architecture and software development. It is expected that this system can be used for the communication and control purpose in the high noise environments such as the operation of the MeV energy implanter or other high power, high noise systems.