• 한국추진공학회지
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• 제15권2호
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• pp.62-67
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• 2011

현재의 많은 유도무기들은 발사관에 장착되어 이동된다. 발사관이란 유도탄등이 외부환경에 노출되지 않도록 유도탄을 보호하고, 발사시 유도탄을 가이드 하는 역할을 한다. 발사관에 장착되어 있는 유도탄은 발사관에 견고하게 장착되어 이동되어야 하며, 작전시 원하는 시간에 분리되어야 한다. 이를 위하여 구조적인 안전성이 크고, 분리 응답이 빠른 파이로 장치인 폭발볼트가 많이 사용된다. 폭발볼트는 화약의 폭발력에 의해 볼트몸체가 절개됨으로써 볼트에 의해 결합되고 있던 부분이 분리되는데, 폭발 볼트는 분리시 파편, 화염 및 pyro-shock이라는 큰 진동과 충격을 수반하므로 정밀한 유도무기에는 사용이 제한된다. 이와 같은 문제점을 해결하기 위하여 압력카트리지에서 발생하는 압력을 분리력으로 사용하여, 충격이 작고, 분리파편이 발생하지 않는 분리장치인 볼타입 분리볼트를 개발하였다. 본 연구에서는 볼타입 볼트의 분리현상을 분석하고, 볼타입 분리볼트의 분리 안전율을 정량적으로 제시하였다.

• Korean Chemical Engineering Research
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• 제51권4호
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• pp.476-481
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• 2013

본 연구에서는 물리적 특성이 유사한 에틸벤젠과 파라자일렌의 혼합물을 분리하고자 MFI형 제올라이트(TS-1, ZSM-5, Silicalite-1) 분리막을 제조하였으며 이를 이용하여 기상에서 분리 실험을 진행하였다. 제올라이트 입자가 코팅된 분리막을 제조함에 있어서 마이크로웨이브 합성 방법을 사용하여 합성 시간을 단축하였으며, 500 nm 내외의 균일한 입자를 튜브타입의 지지체 막에 안착시켜 제올라이트 입자가 $3{\sim}4{\mu}m$ 두께로 치밀하게 코팅된 분리막을 제조하였다. 제조한 분리막으로 에틸벤젠/파라자일렌 혼합물 원료의 혼합비를 변경하여 투과 분리한 결과 에틸벤젠:파라자일렌=5:5 비율에서 가장 높은 분리도를 가짐을 알 수 있었다. 세 종류의 서로 다른 제올라이트 물질(TS-1, ZSM-5, Silicalite-1)을 각각 코팅하여 제조된 분리막을 이용하여 $160{\sim}220^{\circ}C$의 실험온도에서 에틸벤젠/파라자일렌을 투과 실험을 실시한 결과, TS-1 분리막이 $1,666mol/m^{2*}s^*Pa$의 가장 높은 투과 플럭스를, Silicalite-1 분리막이 1.73의 가장 높은 분리도를 $200^{\circ}C$의 온도에서 각각 보임을 확인할 수 있었다.

• 해양환경안전학회지
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• 제29권4호
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• pp.338-347
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• 2023

진해만은 태풍 내습 시 피항 선박이 폭주하고 강한 바람 등의 영향으로 주묘가 자주 발생하며 이에 따른 선박 간 충돌 및 좌초 등 해양사고 발생 개연성이 매우 높다. 본 연구에서는 우리나라 해역 특성에 맞는 진해만 정박지의 선박 간 안전이격거리 설정을 위한 연구를 수행하였다. 진해만 태풍 피항지에는 태풍 내습 시 평균 100 ~ 200여척의 선박이 정박을 하고 있으며 풍속이 25m/s 이상되는 강한 외력에서 전체 선박의 약 70%에 주묘가 발생하는 상황인 것으로 분석되었다. 본 연구에서는 국내외 설계기준 상 제시된 황천 시 정박 선박간 이격거리, 실제 피항지로서 사용된 진해만 피항선박 간 이격거리, 강한 외력에 따른 선박 표류 시 적정 안전거리 등을 분석하여 제시하였다. 그 결과 설계기준 상의 최소 기준과 비상조치 시간을 고려하여 약 400 ~ 900m의 안전이격거리가 필요하며, 공간상의 여유가 있는 경우에는 700 ~ 900m 이격거리 설정이 필요한 것으로 도출하였다. 본 연구의 결과는 향후 진해만 피항지를 이용하는 선박에 대해 선박간 안전 이격거리를 위한 지침 수립 시 활용이 가능할 것으로 기대된다.

• Advances in materials Research
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• 제2권1호
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• pp.15-36
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• 2013

Incorporation of polar functional moieties into polyethylene (PE) film has been achieved by graft copolymerization of polar monomers such as methacrylic acid (MAAc) and acrylamide (AAm) on to PE film, preirradiated with ${\gamma}$-rays from $^{60}Co$ source, using benzoyl peroxide (BPO) as initiator in aqueous medium. Percentage of grafting of MAAc and AAm was determined as a function of irradiation dose, monomer and initiator concentration, temperature, reaction time and amount of water. Maximum percentage of grafting of MAAc (1453%) and AAm (21.28%) was obtained at [MAAc] = $235.3{\times}10^{-2}$ mol/L, [AAm] = $23.4{\times}10^{-2}$ mol/L, [BPO] = $5.5{\times}10^{-2}$ mol/L and $16.5{\times}10^{-2}$ mol/L at $80^{\circ}C$, $90^{\circ}C$ in 180 min and 90 min respectively. The grafted PE films were characterized by FTIR, Thermogravimetric analysis (TGA) Scanning Electron Micrography (SEM) and X-ray diffraction methods. Some selective properties of grafted films such as swelling behavior, ion and metal uptake have been carried out. The biodegradation studies of the grafted PE films have also been investigated. The grafted films developed superior swelling behavior with maximum swelling (480%) in water as compared to pristine PE (13.55%), better thermal stability and ion and metal uptake studies showed promising results that can be effectively used for desalination of brackish water and separation of metals from the industrial effluents.

• 한국광학회지
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• 제8권4호
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• pp.260-266
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• 1997

DCG(dichromated gelatin : 7.mu.m 두께) 필름을 이용하여 홀로그래픽 편광분리(Holographic Polarization Separation : HPS)소자를 설계 제작하였다. 제작한 HPS소자의 편광특성을 노출시간, 입사각, 편광각 등의 몇가지 물리적 변수들을 이용하여 조사하였다. 실험결과가 Kogelnik의 결합 파동이론에 기초한 이론적 결과와 잘 일치함을 알 수 있었다. 제작한 HPS소자는 633 nm 파장에서 편광 회절 강도비가 500:1(S편광:P편광)이상이였다. 또한 HPS소자의 광 스위치 및 자유공간 광 연결소자로서의 응용 가능성을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.613-631
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• 2013

Cognitive radio (CR) is proposed as a key solution to improve spectral efficiency and overcome the spectrum scarcity. Spectrum sensing is an important task in each CR system with the aim of identifying the spectrum holes and using them for secondary user's (SU) communications. Several conventional methods for spectrum sensing have been proposed such as energy detection, matched filter detection, etc. However, the main limitation of these classical methods is that the CR network is not able to communicate with its own base station during the spectrum sensing period and thus a fraction of the available primary frame cannot be exploited for data transmission. The other limitation in conventional methods is that the SU data frames should be synchronized with the primary network data frames. To overcome the above limitations, here, we propose a spectrum sensing technique based on blind source separation (BSS) that does not need time synchronization between the primary network and the CR. Moreover, by using the proposed technique, the SU can maintain its transmission with the base station even during spectrum sensing and thus higher rates are achieved by the CR network. Simulation results indicate that the proposed method outperforms the accuracy of conventional BSS-based spectrum sensing techniques.

• 한국염색가공학회지
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• 제17권4호
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• pp.21-26
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• 2005

A combination separation system is composed of three parts, simple microfiltration unit for the pretreatment of real waste IPA, pervaporation unit with plate and frame type module(the effective membrane area 9,040$cm^2$), and simple ultrafiltration unit as a refiner. Utrafiltration module with hollow fiber membrane(MWCO 10,000) used to purify waste aqueous IPA solution. In addition, the flux of $CMPA-K^+$ composite membrane for waste aqueous IPA solution was very steady-state with long experiment time(30 days). And the standard deviation($\sigma$) was 0.152 and then the coefficient of variation($CV\%$)was 10.82 The IPA concentration on the membrane performance using pervaporation module system could be increased from $89.85wt(\%)$ to more than $99.90wt\%$ in about 8hr at operation temperature of $70^{\circ}C$ using the pervaporation module system. Therefore, a combination separation process system of simple filtration and pervaporation was very effective for the purpose of the IPA purification and reuse front industrial electronic components cleaning process.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.522-525
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• 2002

A very rapid and efficient separation technique for cellular rhizobial cyclosophoraoses was developed based on fractional precipitation and partition chromatography. Cyclosophoraoses are known to function in the osmotic regulation and root nodule formation of legumes during the nitrogen fixation process. Cyclosophoraoses are produced as unbranched cyclic (1longrightarrow12)-${\beta}$-D-glucans in Agrobacterium or Rhizobium species. Recent research has shown that cyclosophoraoses can form inclusion complexation with various unstable or insoluble guest chemicals, thereby implying great potential for industrial application. Typical separation of pure cellular cyclosophoraoses has been so far carried out by several time-consuming steps, including size exclusion, anion exchange, and desalting liquid chromatographies, with a relatively poor recovery. However, the proposed method demonstrated that the successive application of fractional ethanol precipitation and one step of silica gel-based flash column chromatography was enough to simultaneously purify neutral or anionic forms of cyclosophoraoses. This novel technique is very rapid and provides a high recovery.

• Earthquakes and Structures
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• 제18권2호
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• pp.171-184
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• 2020

The potential of using the roof water tanks as a mitigation measure to minimize the required separation gap and induced pounding forces due to collisions is investigated. The investigation is carried out using nonlinear dynamic analysis for two adjacent 3-story buildings with different dynamic characteristics under two real earthquake motions. For such analysis, nonlinear viscoelastic model is used to simulate forces due to impact. The sloshing force due to water movement is modelled in terms of width of the water tank and the instantaneous wave heights at the end wall. The effect of roof water tanks on the story's responses, separation gap, and magnitude and number of induced pounding forces are investigated. The influence of structural stiffness and storey mass are investigated as well. It is found that pounding causes instantaneous acceleration pulses in the colliding buildings, but the existence of roof water tanks eliminates such acceleration pulses. At the same time the water tanks effectively reduce the number of collisions as well as the magnitude of the induced impact forces. Moreover, buildings without constructed water tanks require wider separation gap to prevent pounding as compared to those with water tanks attached to top floor under seismic excitations.

• 한국수소및신에너지학회논문집
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• 제16권2호
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• pp.180-190
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• 2005

The PSA cycle was performed for the separation of binary gas mixture $H_2/Ar$ (80%/20%) using the six-step two-bed process. Adsorption equilibrium contains a LRC model for equilibrium adsorption isotherms and a LDF model for mass transfer. Aspen ADSIM, simulator was applied to predict the separation performance. The effect of cycle parameters such as feed rate, adsorption pressure and P/F ratio on the separation of hydrogen has been studied in experiment and simulation. In the results, maximize the recovery of hydrogen as a high purity was 13LPM feed flowrate, 120sec adsorption time, 11atm adsorption pressure and 0.1 P/F ratio in a cyclic steady-state come out since 10th cycle.