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日米同盟と東北アジアの安全保障 - 日米安保協力の現狀と課題 -
鄭勛燮 동북아시아문화학회 2005 동북아 문화연구 Vol.1 No.9
Since the end of the World War Ⅱ,a primary objective of the U.S. policy toward the Northeast Asia has been the promotion of peace and stability on this area, that is first and foremost maintained by a credible deterrent against the possible Soviet aggression. The continued basing of the U.S. forces in Japan under the Japan‐U.S. Security Treaty makes this deterrent both possible and credible. Recently, the Japan‐U.S. alliance has been undergoing some changes. The changes stem from the end of the Cold War, September 11 terrorist attacks, and the wars in Afghanistan and Iraq. These factors have forced Japan to form the new Japan‐U.S. security relations. Now, under the Global Posture Review (GPR) plan, Bush Administration is seeking to transform its military into a leaner, more mobile force to deal with the shifting post‐Cold War security environment. The Japan and U.S. also have been negotiating for more than a year over the reorganization of the U.S. forces in Japan. The U.S. still sees Japan as the linchpin of its security policy in the Northeast Asia. The purpose of this paper is mainly to analyze the present conditions and the issues of Japan‐U.S. security cooperation. This paper also examines about the correlation of a Japan‐U.S. alliance and the security of the Northeast Asia by considering the influences which Japan‐U.S. security cooperation has on neighboring countries.
정훈섭 ( Hoon-sup Jung ),현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2020 한국수처리학회지 Vol.28 No.3
Microplastics (MPs) with diameters less than 5 mm in wastewaters are being increasingly discharged into aquatic environment from plastic industries, personal care products, and synthetic textiles. Futher, MPs have a negative impact on the environment due to their extremely low biodegradability. This study aims at investigating the behaviour of MPs in treated waters using real biological nutrient removal (BNR) systems. In terms of shape, the majority of MPs in real wastewaters are fibers and fragments. Most BNR systems achieved high efficiency (>95%) in reducing the MPs from wastewaters. In the BNR systems, the profiles sizes of MPs removal are in the following order: aeration tank (AT) > primary settling tank > total phosphorus removal tank > return sludge > final settling tank (FST). Higher efficiency of MPs removal during aeration in the AT as compared to the other processes resulted in the absorption and fixation of MPs in the activated sludge and biofilm. In contrast, lower efficiency of FST resulted in the MPs not being absorbed, which were floating in treated water without particulate; thus, the floating MPs were discharged without settling due to their lower specific gravity. Therefore, a filtration process should be introduced to effectively reduce the MPs in the effluent before it enters the FTS.
MBR공정의 질소.인저감 효과 개선을 위한 영향인자분석
정훈섭 ( Hoon-sup Jung ),현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2020 한국수처리학회지 Vol.28 No.4
This study aims to investigate the effects of carbon/nitrogen/phosphorus (C/N/P) ratio and recirculation on nutrient removal in a membrane bioreactor (MBR) and anaerobic/aerobic(AN/O) processes coupled with MBR by using real facilities. Treatment capacities of a MBR and an AN/O-MBR are 5,000 m3/d and 15,000 m3/d, respectively. Influent characteristics of real wastewater used for this study are BOD <200 mg/L, COD <220 mg/L, T-N <65 mg/L, T-P <8 mg/L, and E-coli.< 100,000 No/mL. In reducing organics and nutrients, AN/O-MBR performance achieved higher efficiencies (5-40% higher) than those of MBR. In particular, the removal efficiencies of N and P by AN/O-MBR were about 0.2-0.4 times higher than those by MBR while both MBR and AN/O-MBR achieved high efficiencies ( >95%) in reducing chemical oxygen demand (COD). For AN/O-MBR in reducing total nitrogen (T-N), internal recirculation (IR) of 1.5-2.0Q achieved higher efficiencies (10-30% higher) than those of IR. In particular, the addition of methanol as carbon source into MBR process achieved higher efficiencies (20-25% higher) than that without methanol. For total phosphorus (T-P) removal, the addition of polyaluminum chloride (PAC) as coagulant into the MBR process achieved higher efficiencies (30-80%) than that without PAC. For transmembrane pressure (TMP) build-up, the results reveal that the additions of methanol and PAC have effects in mitigating TMP build-up compared to MBR process without them.
정훈섭 ( Hoon-sup Jung ),송인수 ( In-soo Song ),현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2021 한국수처리학회지 Vol.29 No.3
Membrane bioreactor (MBR) combining an activated sludge process and membrane filtration could achieve high nutrient removal efficiency and complete biomass retention without a secondary clarifier. Membrane fouling remains the most challenging issue in MBR operation and attracts considerable attention in MBR studies. The objective of this study is to investigate the influence of permeate flux, aeration mode and strength, and mixed liquor suspended solid (MLSS) on membrane filtration of small-scale MBR (the capacity 100㎥/d), which consisted of anaerobic, anoxic, and aeration tank coupled with membrane. Experiments were conducted with real MBR using real wastewater (BOD <250 mg/L, COD <220 mg/L, T-N <65 mg/L, T-P <8 mg/L, E-coli <100,000 no/mL). As a result, the increase of both permeate flux and MLSS increased TMP of MBR while the increase of aeration strength decreased the TMP. Compared to the existing operation conditions of MBR, the operation conditions of shorter filtration time (8 min on/ 2 min off) for a cycle and lower MLSS (<3000 mg/L) in MBR resulted in longer filtration duration time (about two times) as well as the reduction of cleaning chemical.
수온과 포기강도가 소규모 MBR공정의 막여과 효율에 미치는 영향
정훈섭 ( Hun-seob Jung ),현길수 ( Kil-soo Hyun ) 한국수처리학회(구 한국수처리기술연구회) 2019 한국수처리학회지 Vol.27 No.3
The objective of this study is to investigate the influence of water temperature and aeration strength on membrane filtration of small-scale membrane bioreactor (MBR) with the treatment capacity of 100 m<sup>3</sup>/d, which consisted of anaerobic, anoxic, and aeration tank coupled with membrane. Experiments were conducted with real MBR system using real wastewater. Applied transmemrane pressure (TMP) was <0.5 kgf/cm<sup>2</sup>.h. Influent concentrations of real wastewater were in the range of BOD <100 mg/L, COD <70 mg/L, SS <105 mg/L, T-N <23 mg/L, T-P <3 mg/L, E-coli <110,000 no/mL, MLSS < 5,000 mg/L, respectively. As a result, the increase of both water temperature and aeration strength decreased TMP of MBR system. The efficiency of MBR system achieved the high removal for organic and particulate with removal efficiencies of >92%, while it achieved a relative low removal for nutrients with removal efficiencies of <53%.