• 지질공학
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• 제16권2호
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• pp.145-152
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• 2006

다양한 산업의 발달은 우리 인간이 사용해야 하는 수자원으로 여러 가지 형태의 위해성을 함유하는 유해화학물질들의 수적 양적 증가를 초래하였다. 이로 인해 효율적인 수자원의 이용을 위해서는 수자원으로 유입되는 오염원의 사전 처리가 필수적인 것으로 인지되어 국내에서도 수자원으로 유입되는 오염물질에 대해 총량으로 방류업체의 수질을 규제하기 시작했다. 그러나 아직까지도 규명되지 않은 화학물질들이 대다수를 차지하므로 이에 대한 모니터링이 매우 중요한 역할로 자리하고 있다. 본 연구에서는 낙동강 수계로 유입되는 섬유 및 화학 산업폐수를 중심으로 미량유해화학물질을 계측하여 이들이 낙동강 수계에 미치는 유해성을 검토하였다. 대상으로 한 7개 업체로부터의 유입수와 방류수에서 검출되는 VOCs(volatile organic compounds) 중에서는 클로로포름(chloroform)이 가장 높은 빈도로 검출되었으며, 동일한 업체에서도 노출수준이 일정하지 않아 이의 관리에 어려움이 예상된다. 그러나 이들 업체의 방류수가 유입되는 하수처리장에서는 콜로로포름의 처리효율이 높아(88% 이상) 낙동강 수계의 영향은 그리 크지 않을 것으로 추정된다. 한편, 섬유/화학관련 산업체의 유입수와 방류수로부터 노출되는 EU지정우선물질에 대해 조사한 결과, 검출현황에 대한 일정한 경향을 찾을 수 없을 뿐만 아니라 국내자료의 축적도 거의 없는 상태임을 감안하여 지속적인 모니터링을 통해 국가정책에 활용 할 수 있는 자료구축을 해 나가야 할 것이다.

• 상하수도학회지
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• 제19권4호
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• pp.429-436
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• 2005

A coagulation/ultrafiltration membrane hybrid system was operated to treat river water with capacity of $0.06m^3/d$. The impact on membrane fouling by flux and linear velocity was investigated. It is known that pressure increase is proportional to flux increase. However, pressure increase was much faster than theoretical value in the pilot plant test. So it was suggested that flux was on important factor in ultrafiltration of continuous operation. Membrane fouling was decreased when linear velocity was increased. This phenomenon was found more obviously without coagulation. With the combination of coagulation and sedimentation, membrane fouling was not reduced conspicuously. Big particles formed during coagulation and sedimentation were destroyed by feed and circulation pumping, which resulted in little effect on membrane fouling reduction. The degree of destruction was similar at various linear velocities. In this study, the hollow fiber membrane was used and the system was operated in pressure type module. In case of the system used in this study, membrane fouling has been affected lightly by linear velocity variation when coagulation pretreatment was applied.

• 센서학회지
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• 제23권4호
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• pp.272-277
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• 2014

At present, the index of chemical oxygen demand (COD) is widely used as an indicator of organic water pollution with biochemical oxygen demand (BOD). But, traditional COD measurement method are not only with various chemical reagents exhausted, but also long time consumed, the operation procedure and the modification are much professional. This paper reported a novel COD measurement system using double-beam and multiple wavelength analysis UV-VIS spectrometries. It consists of pulsed xenon lamp, two-way optical fiber, optical switch, spectrometer and main processor. Proposed COD measurement system obtains any spectral information of water sample (KHP standard sample and two river water and wastewater) and reference sample (distilled water) in the range of 200~520 nm, corresponding to the COD concentration from 0 to 300 mg/L through calculating the UV absorbance. The system show improved precision and can work continuously fast at time interval about 25 seconds.

• Journal of Chest Surgery
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• 제27권9호
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• pp.723-731
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• 1994

We have modified the isolated perfused working rabbit lung model [IPWL] by perfusing the isolated lung with a hollow fiber membrane deoxygenator.For assessment the stored lung was ventilated with FIO2 0.4 and perfused with 37$^{\circ}$C deoxygenated circulating blood at a rate 5ml/kg/min for several hours until lung failure.We chose to compare our developing solution which contained low potassium and pentastarch with the modified Euro-Collins solution .Experiments were divided into four groups[n=6] based on the type of flushing preservation solution and preservation time.The flushed lungs were then preserved into same solution at 8~10$^{\circ}$C with 100% O2 inflated condition for 1 or 20 hours.These following results were obtained.The IPWL model requires only one animal per experiment and allows for the continuous assessment of aerodynamic performance. This should therefore be used as screening test in lung preservation.One hour preservation groups, there were no significant difference in recovery rates of PaO2, PAP and Paw. Survival time in the one hour preservation groups were very significant long in the Group II[LPPS, p<0.01]. Twenty hours preservation groups, there were no significant difference in the recovery rates of PAP and Paw between Group III[m-ECS] and Group IV[NS], but PaO2 was significantly worse at onset of reperfusion in Group III when compared with Group IV [p<0.05]. And also survival time in the 20 hours preservation groups were significant long in the Group IV [p<0.05].

• 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.