• 한국환경농학회지
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• 제21권2호
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• pp.144-148
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• 2002

본 연구에서는 농어촌취락배수의 효율적 처리를 위해 수생식물인 부레옥잠과, 미나리를 이용한 연속식 실험에서 유기물부하(COD)와 Total N, Total P 등을 HRT와 농도를 달리하여 제거효율을 측정하였다. 유기물(COD)의 제거효율은 HRT가 2 day인 부레옥잠조에서는 평균 50%의 제거율을 보였으며, 미나리조에서는 HRT 1.2$\sim$2 day 동안 30$\sim$50%의 제거율을 보였다. 영양염류의 제거효율은 총 질소의 경우 부레옥잠조는 약 329 kg $N/ha{\cdot}day$의 부하에서 HRT 2$\sim$3 day인 경우 40$\sim$53%가 제거되었으며, $NH_4^+-N$의 제거효율은 평균 52%로 Total N의 제거효율보다 다소 높았으며, 인은 8.2 kg $P/ha{\cdot\}day$의 부하에서 HRT 2$\sim$3 day인 경우 31$\sim$40%로 조사되었다. N 및 P 흡수율은 미나리보다 부레옥잠이 높게 나타났으며, 인의 흡수율은 질소의 흡수에 비해 낫게 조사되었다.

• 한국축산식품학회지
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• 제39권1호
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• pp.45-53
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• 2019

This study observed the effects of the double combination of temperatures-times (2 temperatures: 2 times combination, 2T2T) in sous vide cooking method on the physicochemical properties and collagen solubility (CS) of semitendinosus muscle from cattle and goat as a comparison to common sous vide treatment (1 temperature: 1 time combination, 1T1T). The new invention of sous vide cooking method (2T2T) cooked at the first temperature at $45^{\circ}C$ for 3 h, and the second temperature at $60^{\circ}C$, $65^{\circ}C$, and $70^{\circ}C$ for 3 h, and labeled as N45-60, N45-65, and N45-70, respectively. While, common sous vide treatment (1T1T) were cooked directly for 6 h at $60^{\circ}C$ (T60), $65^{\circ}C$ (T65), and $70^{\circ}C$ (T70). Results revealed that cooking with 2T2T treatment improved the water-holding capacity and reduced the cooking loss of both beef and goat meat. The $L^*$ values have no apparent changes between treatment in beef and goat meat, while $a^*$ values of N45-60 treated goat presented markedly higher values than other treatments but an only slight increase in beef at the same treatment (p>0.05). Again, 2T2T treatment tended to decrease mean shear force (SF) values for beef and goat meat with the lowest SF values recorded at N45-60, and the CS no or less influenced this value. Therefore, the application of innovative sous vides cooking method (2T2T) presented comparable values in the treated beef and goat meat as compared to common sous vide method (1T1T).

• 대한한의학회지
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• 제22권3호
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• pp.119-128
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• 2001

Objectives: Daechu (Dazhui: GV 14 (Governor Vessel))-point is located between the spinous process of the 7th cervical vertebra and that of the 1st thoracic vertebra. GV 14 has been used to treat high fever, neck pain, common cold, headache and so on. Fever may badly affect the improvement of stroke patients, so we investigated whether wet-cupping at GV 14 had effects on fever. Methods: In this study, 100 stroke patients were studied from Nov. 1999 to Oct. 2000. They were divided into the Sample group (n=49) and Control group (n=5l). The Sample group (n=49) was divided into Sample-Severe (n=2l), Sample-Mild (n=12), and Sample-Normal groups (n=16) and the Control group (n=5l) was divided into Control-Severe (n=8) and Control-Mild (n=43). We checked body temperature 6 times (just before treatment, after 30 ruin., 60, 90, 120 (2 hrs.), and 240 ruin. (4 hrs.)) in the Sample group and 3 times (just before treatment, after 120 min. (2 hrs.), and 240 ruin. (4 hrs.)) in the Control group. Results: In comparison with fever between before treatment and after 2 and 4 hours in each group, fever in the Sample subgroups decreased significantly in all cases, fever in the Control subgroups didn't decrease significantly in most cases except fever after 4 hours in the Control-Mild group. In comparison with fever differences between the Sample and Control group, fever of the Sample group more significantly decreased than that of the Control group in all comparisons. In comparison with fever among sample subgroups, fever of the Sample-Severe group decreased more than that of the Sample-Mild group but it was not significant. Conclusions: This study suggested that wet-cupping at GV 14 has significant effects on fever in stroke patients. We hope that this treatment will be used more widely as an emergent treatment.

• 한국물환경학회지
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• 제22권4호
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• pp.599-604
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• 2006

Nitrogen removal with the combined SHARON (Single reactor system for high ammonium removal over nitrite)ANAMMOX (Anaerobic ammonium oxidation) process using the effluent of ADEPT (Anaerobic digestion elutriated phased treatment) slurry reactor with very low C/N ratio for piggery waste treatment was investigated. For the preceding SHARON reactor, ammonium nitrogen loading and removal rate were $0.97kg\;NH_4-N/m^3_{reactor}/day$ and $0.68kg\;NH_4-N/m^3_{reactor}/day$ respectively. In steady state, bicarbonate alkalinity consumption for ammonium nitrogen converted to $NO_2-N$ or $NO_3-N$ was 8.4 gram per gram ammonium nitrogen. The successive ANAMMOX reactor was fed with the effluent from SHARON reactor. The loading and removal rate of the soluble nitrogen defined as the sum total of $NH_4-N$, $NO_2-N$ and $NO_3-N$ in ANAMMOX reactor were $1.36kg\;soluble\;N/m^3_{reactor}/day$ and $0.7kg\;soluble\;N/m^3_{reactor}/day$, respectively. The average $NO_2-N/NH_4-N$ removal ratio by ANAMMOX was 2.41. Fluorescence in situ hybridization (FISH) analysis verified that Candidatus Kuenenia stuttgartiensis were dominate, which means that they played an important role of nitrogen removal in ANAMMOX reactor.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2309-2314
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• 2012

Ag deposited N-$TiO_2$ composite nanoparticles were prepared via $NH_3$ plasma treatment. X-ray diffraction, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared $TiO_2$ samples. The plasma treatment did not change the phase composition and particle sizes of $TiO_2$ samples, but extended its absorption edges to the visible light region. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of Ag deposited N-$TiO_2$ composite nanoparticles were much higher than Ag-$TiO_2$, N-$TiO_2$, and P25. A possible mechanism for the photocatalysis was proposed.

• Membrane and Water Treatment
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• 제4권1호
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• pp.69-81
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• 2013

The pH-dependent inter-conversion of the three free chlorine species ($Cl_2$, HOCl, OCl-) present in the aqueous hypochlorite solution was theoretically investigated. Each species was found overwhelmingly present in a characteristic pH range. Hypochlorite treatment of the polyamide membrane was carried out over these pH ranges and various membrane responses were observed. As pH is less than 8, membrane tends to be N-chlorinated by $Cl_2$ and HOCl, and N-chlorinated membrane showed reduced water permeance and salt rejection. As pH rises to 10-12, $OCl^-$ appears to be the dominating chlorine species. Membrane hydrolysis was found to well interpret the improved water permeance and salt rejection. When the pH is between 8-10, both N-chlorination and hydrolysis contribute to the response of the membrane, and the treated membrane showed improved salt rejection but reduced water permeation. Excessive hydrolysis occurred while the membrane was treated at pH 13 for the much stronger alkalinity.

• 열처리공학회지
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• 제13권2호
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• pp.103-107
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• 2000

Effect of aging treatment on the microstructures and mechanical properties of 7N01 Al alloy was investigated by differential scanning calorimetry, transmission electron microscopy, microhardness measurement and tensile test. Maximum hardness(125.7Hv) and tensile strength(447.3MPa) were obtained from the specimen aged at $120^{\circ}C$ for 32hrs. The major precipitation hardening phase was confirmed as coherent $MgZn_2({\eta}^{\prime})$ phase. Microhardness changes after peakaged condition showed very large decrease upon increased aging time. This result was attributed to the high transformation rate from coherent ${\eta}^{\prime}$ to incoherent ${\eta}$. It was found that the precipitation sequence of 7N01 Al alloy was GP zone${\rightarrow}$metastable spherical hcp $MgZn_2({\eta}^{\prime}){\rightarrow}$ equilibrium rodlike hcp $MgZn_2({\eta})$.

• 한국표면공학회지
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• 제48권6호
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• pp.269-274
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• 2015

In this experiment, post-nitriding treatment was performed at $400^{\circ}C$ on AISI 316 stainless steel which was plasma carburized previously at $430^{\circ}C$ for 15 hours. Plasma nitriding was implemented on AISI 316 stainless steel at various gas compositions (25% $N_2$, 50% $N_2$ and 75% $N_2$) for 4 hours. Additionally, during post nitriding Ar gas was used with $H_2$ and $N_2$ to observe the improvement of surface properties. After treatment, the behavior of the hybrid layer was investigated by optical microscopy, X-ray diffraction, and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. Meanwhile, it was found that the surface hardness increased with increasing the nitrogen gas content. Also small percentage of Ar gas was introduced in the post nitriding process which improved the hardness of the hardened layer but reduced the corrosion resistance compared with the carburized sample. The experiment revealed that AISI 316L stainless steel showed better hardness and excellent corrosion resistance compared with the carburized sample, when 75% $N_2$ gas was used during the post nitriding treatment. Also addition of Ar gas during post nitriding treatment degraded the corrosion resistance of the sample compared with the carburized sample.

• 한국물환경학회지
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• 제22권2호
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• pp.222-229
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• 2006

The treatment performance and operational parameters of a tertiary wastewater treatment process a biological filtration system were investigated. The biological filtration system consisted of a nitrification filter (Fiter 1) and a polishing filter with anoxic and aerobic parts (Filter 2). SS, T-C-BOD, and T-N in effluent were kept stable at less than 3, 5 mg/L, and 5 mgN/L, respectively, under a HRT in Filter (filter-bed) of 0.37~2.3 h. T-N at the outlet of Filter 2 were about 1~5 mgN/L under the condition of LV of 50~202 m/d. In Filter 2, denitrification was accomplished under LV of 50~168 m/d in a 1 m filter-bed. However, the denitrification capacity reached the maximum when the linear velocity was increased to 202 m/d. Relationship between increase in microorganism and headloss was clearer in Filter 2. As a result, the denitrification rate increased from 1.0~2.3 kgN/($m^3-filter-bed{\cdot}d$) as the headloss increased. The COD removal rate was 6.0~9.6 kgCOD/($m^3-filter-bed{\cdot}d$) when operated with Filters 1 and 2. These results mean that captured bacteria contributed a part of COD consumption and denitrification. The maximum nitrification and denitrification rate was 0.5 and 4 kgN/($m^3-filter-bed{\cdot}d$) in Filter 1 and 2.The ratio of backwashing water to the treated water was about 5~10 %. In Filter 1, wasted sludge in backwashing was only 0.7~5.3 gSS/($m^3$-treated water). In Filter 2, added methanol was converted into sludge and its value was 8.0~24 gSS/($m^3$-treated water). These results proved that this process is both convenient to install as tertiary treatment and cost effective to build and operate.

• 한국환경과학회지
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• 제25권11호
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• pp.1493-1498
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• 2016

The efficiencies of Gang-Byeon sewage treatment facilities, which are based on GPS-X modelling, were analysed and used to design recycle water treatment processes. The effluent of an aeration tank contained total kjeldahl nitrogen (TKN) of 1.8 mg/L with both C-1 and C-2 conditions, confirming that most ammonia nitrogen ($NH_3{^+}-N$) was converted to nitrate nitrogen ($NO_3{^-}-N$). The concentrations of $NH_3{^+}-N$ and $NO_3{^-}-N$ were found to be 222.5 and 227.2 mg/L, respectively, with C-1 conditions and 212.2 and 80.4 mg/L with C-2 conditions. Although C-2 conditions with higher organic matter yielded a slightly higher nitrogen removal efficiency, sufficient denitrification was not observed to meet the discharge standards. For the total nitrogen (T-N) removal efficiency, the final effluent concentrations of T-N were 293.8 mg/L with biochemical oxygen demand (BOD) of 2,500 mg/L, being about 1.5 times lower than that (445.3 mg/L) with BOD of 2,000 mg/L. Therefore, an external carbon source to increase the C/N ratio was required to get sufficient denitrification. During the winter period with temperature less than $10^{\circ}C$, the denitrification efficiency was dropped rapidly even with a high TKN concentration (1,500 mg/L). This indicates that unit reactors (anoxic/aerobic tanks) for winter need to be installed to increase the hydraulic retention time. Thus, to enhance nitrification and denitrification efficiencies, flexible operations with seasons are recommended for nitrification/anoxic/denitrification tanks.