암모니아성 질소(NH4-N)는 산업 폐수, 농업 및 축산 폐수에 포함되어 있으며 인과 함께 수질의 부영양화를 일으 키는 물질로 잘 알려져 있다. 또한 망간(Mn)과 비소(As)는 광산 처리수 등에 포함되어 있으며, 수질 오염의 원인 물질로 알려져 있다. 천연 제올라이트는 수중에서 암모니아성 질소를 제거하는데 사용되고 있지만 낮은 흡착능력을 가진다. 이러한 천연 제올라이트의 낮은 흡착능력을 개선하기 위해 Na+, Ca2+, K+, Mg2+로 이온 치환을 진행하였다. 암모니아성 질소(NH4-N)의 흡착량과 제거율은 Na+로 이온 치환된 제올라이트에서 0.66 mg/g과 89.8%로 가장 높은 값을 보였다. 이온 치환된 제올라이트 를 이용하여 Mn과 As의 흡착실험을 진행하였다. Mg2+로 이온 치환된 제올라이트에서 Mn과 As의 높은 흡착량과 제거율을 보였다.

High-level heteroatom, N and S, dual-doped graphene with an improved mesoporous structure was fabricated via facile in situ carbonization and used as metal-free cathode for non-aqueous lithium oxygen batteries. The prepared cathode delivered an ultrahigh specific capacity of 22,252 mAh/g at a current density of 200 mA/g as well as better cycling reversibility because of the larger and copious mesopores, which can promote the penetration of oxygen, electrons, and lithium ions and the ability to accommodate more discharge products, e.g., Li2O2, in Li–O2 batteries. The material had a high level of heteroatom co-doping in the carbon lattice, which enhanced the electrical conductivity and served as active sites for the oxygen reduction reaction.

In this paper, nitrogen (N)-doped ultra-porous carbon derived from lignin is synthesized through hydrothermal carbonization, KOH activation, and post-doping process for CO2 adsorption. The specific surface areas of obtained N-doped porous carbons range from 247 to 3064 m2/g due to a successful KOH activation. N-containing groups of 0.62–1.17 wt% including pyridinic N, pyridone N, pyridine-N-oxide are found on the surface of porous carbon. N-doped porous carbon achieves the maximum CO2 adsorption capacity of 13.6 mmol/g at 25 °C up to 10 atm and high stability over 10 adsorption/desorption cycles. As confirmed by enthalpy calculation with the Clausius–Clapeyron equation, an adsorption heat of N-doped porous carbon is higher than non-doped porous carbon, indicating a role of N functionalities for enhanced CO2 adsorption capability. The overall results suggest that this carbon has high CO2 capture capacity and can be easily regenerated and reused without any clear loss of CO2 adsorption capacity.

Comparisons between bare carbon (CPs) and nitrogen-doped carbon nanoparticles (N-CPs) synthesised using hydrothermal reaction are carried out. It was found that hydrothermal reaction of citric acid yields graphene-like sheets, while the nitrogen doping using ethylenediamine resulted in amorphous polymeric ball-like hydrocarbons devoid of any aromatic rings. Although the Fourier transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy indicate the presence of carbon–carbon double bonds (C=C), and the ground states of both materials are very deep (> 7.8 eV) as measured by ultraviolet photoelectron spectroscopy. This indicates the conjugation is very short. This is supported by the fact that both materials are UV blue emitting peaking at 375 nm probably originating from C=C.

대기오염물질 중 미세먼지는 심각한 사회적 환경문제로 인식되고 있다. 미세먼지의 원인 물질 중 하나인 질소산화물(NOx)은 석탄화력발전소의 연소공정에서 주로 발생하므로 효율적인 NOx 제거가 필요한 실정이다. 본 연구에서는 선택적 촉매 환원법(Selective Catalytic Reduction, SCR)을 이용한 NOx 제거에서 TiO2 광촉매의 NO 제거효율을 연구하였다. NO 제거효율을 평가하기 위해 발열제가 내장된 Al2O3 기판 표면에 TiO2 촉매와 인산염의 접착 바인더를 혼합하여 도포한 후 제조된 기판을 열처리하면서 실험을 수행하였다. 온도에 따른 촉매의 NO 제거효율을 평가하였고, 촉매의 물리화학적 특성을 위하여 XRD, SEM, TG-DTA, BET 분석을 수행하였다. NOx 제거 효율은 시간에 따른 온도변화(250℃∼500℃) 로 20분에서 제거효율은 58.7%∼65.9%이며, 30분에서 63.7%∼66.0%로 나타났다. 질소산화물 제거용 SCR로 사용되는 TiO2는 300℃가 제거효율이 가장 효율적인 것으로 판단된다.

올레핀은 석유화학산업에서 대부분의 물질의 근간이 되는 핵심적인 물질이며 특히 고분자 합성에 있어 매우 중요하다. 이러한 올레핀 물질을 효율적으로 분리/가공하는 공정은 산업발전에 있어 지대한 영향을 끼친다. 본 연구에서는 올레핀 물질 중 프로필렌 기체를 선택적으로 분리하는 고분자 복합막을 제조하여 투과 및 선택 성능을 증대시키고자 고투과성 매질 인 poly(1-trimethylsilyl-1-propyne) (PTMSP)에 양친성 고분자를 이용하여 개질하였다. 또한 올레핀 분자와 상호작용이 있는 AgBF4 염 및 촉진수송을 극대화 시키기 위하여 이온성 액체인 EMIM-BF4를 첨가하여 올레핀/질소 투과 분리 성능을 향상시 켰다. 기존 PTMSP 복합막의 경우 굉장히 높은 자유부피를 가져 높은 기체 투과성능을 보이는 반면 투과시키고자 하는 기체에 대한 선택적인 분리 성능이 매우 떨어져 낮은 선택도를 보인다. 이를 극복하고자 양친성 고분자를 PTMSP 계면에 그래프트 공중합을 시켰으며 올레핀과 높은 상호작용을 보이는 AgBF4 염 및 EMIM-BF4 이온성 액체를 첨가하여 프로필렌/질소에 대한 선택도를 향상시켰다.

울금(Curcuma longa L.)의 산화억제 및 질소산화물 소거활성 등 기능성 소재로서 활용 가능성을 검토한 결과, 프로안토시아니딘(proanthocyanidin) 함량은 69.000±2.737 mg catechin equivalents (CE)/g dry weight으로 확인되었으며, 증류수(distilled water, DW), 70% 에탄올 및 노르말 부탄올(n-butanol)의 3가지 용매를 사용한 추출 수율은 DW (17.11%), 70% 에탄올(15.26%), 노르말 부탄올(4.12%) 순으로 관찰되었다. 총 플라보노이드(total flavonoid) 함량은 DW, 70% 에탄올 및 노르말 부탄올에서 각각 0.032, 0.512 및 2.221 mg quercetin equivalents (QE)/g의 함량으로 나타났고, 노르말 부탄올에서는 유의적인 차이를 보이며 높게 관찰되었다(p<0.05). Nitric oxide (NO) 라디칼 소거 활성은 농도 별(0.2~0.8 mg/mL) DW에서 15.64~26.20%, 70% 에탄올 10.52~20.76%, 노르말 부탄올 에서 13.39~69.92%로 확인되었다. Nitrite (NO2) 소거활성은 DW 및 70% 에탄올과 비교하였을 때 노르말 부탄올에서 강한 NO2 소거활성을 보였다. β-carotene 탈색 저해활성은 DW에서 8.81~25.93%, 70% 에탄올 1.20~20.20%, 노르말 부탄올 12.08~43.93%로 나타났다. 지질과산화 저해활성은 DW, 70% 에탄올 및 노르말 부탄올에서 각각 5.60~27.54%, 37.78~50.79% 및 41.79~46.39%로 동정되었다. 이에, 천연 항산화제 등 기능성 소재로서의 활용 가능성이 있을 것으로 사료된다.

Recently, quantitative analyses of food web structure based on carbon and nitrogen stable isotopes are widely applied to environmental assessments as well as ecological researches of various ecosystems, particularly rivers and streams. In the present study, we analyzed carbon and nitrogen stable isotope ratios of POM (both planktonic and attached forms), zooplankton, benthic macroinvertebrates and fish collected from 6 sites located at Nakdong River. Samples were collected from upstream areas of 5 weirs (Sangju, Gangjeong- Goryeong, Dalseong, Hapcheon-Changnyeong, and Changnyeong-Haman Weirs) and one downstream area of Hapcheon-Changnyeong Weir in dry season (June) and after rainy season (September). We suggested ranges of their carbon and nitrogen stable isotope ratios and calculated their trophic levels in the food web to compare their temporal and spatial variations. Trophic levels of organisms were relatively higher in Sangju Weir located at upper part of Nakdong River, and decreased thereafter. However, the trophic levels were recovered at the Changnyeong-Haman Weir, the lowest weir in the river. The trophic level calculated by nitrogen stable isotope ratios showed more reliable ranges when they were calculated based on zooplankton than POM used as baseline. The suggested quantitative ecological information of the majority of biological communities in Nakdong River would be helpful to understand the response of river food web to environmental disturbances and can be applied to various further researches regarding the quantitative approaches for the understanding food web structure and function of river ecosystems as well as restoration.

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of O2 ⦁- and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DLpenicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.

The aim of this present study was to investigate the impact of different seeding rate and nitrogen fertilizing levels on the seed yield and feed value of oats(Avena sativa L.) grown in Gyeongbuk area for two years. The experiment was arranged in split plot design with 3 main plots(100, 130 and 160 kg of seed/ha) and 4 subplots(0, 50, 70 and 90 kg N/ha), with 3 replicates. Heading, flowering, and maturing dates of oats sown in spring 2017, delayed by two days compared to that of spring 2016, and the plant height of spring 2017 were significantly shorter than that of spring 2016(18.1 ~ 23.4 cm). In addition, the highest number of stems and number of panicles according to different seeding rate and nitrogen fertilizing levels were achieved with the seeding rate of 160 kg/ha and 90 kg of N/ha in 2016 and 2017, respectively. In case of seed yield as affected by different seeding rate, the highest seed yield was achieved with a seeding rate of 130 kg/ha(p<0.05), and based on nitrogen fertilizing levels, the highest yield was obtained in 50 kg of N/ha compared to others. The crude fiber(CF), neutral detergent fiber(NDF) and total digestible nutrients(TDN) of oats cultivated and harvested in spring 2016 and 2017 according to different sowing rate were the highest in the seeding rate of 130 kg/ha. The crude protein(CP) content and total digestible nutrients(TDN) of 2016-2017 as influenced by nitrogen fertilizer levels were the highest in the nitrogen fertilizer level of 90 and 50 kg N/ha, respectively. In conclusion, the proper seeding rate and the optimal nitrogen fertilizing level in Gyeongju, Gyeongbuk province were considered to be the most appropriate in 130 kg/ha and 50 kg of N/ha, respectively.

본 연구는 아미노산과 질소원이 증진된 수확후배지를 재사용하고, 느타리에서 영양원으로 사용되는 면실박의 사용을 줄이기 위해 수행되었다. 수확후배지의 질소원 증진을 위해 두 가지의 세균이 사용 되었으며, GM20-4는 느타리버섯의 수확후배지부터 분리되었고, Rhodobacter sphaeroides는 광주시농업기술센터로부터 분양받았다. 처리구에 사용된 수확후배지는 건조 후 사용했으며, 위의 2가지의 미생물 처리에 의해 수확후배지의 총질소 함량은 0.34% 증가되었다. 8% DSMS 가진 T1처리구와 18% D-SMS가 첨가된 T2가 대조와 T3처리구보다 발이율이 높았으며, 생물학적 효율은 대조 110%, T1이 114%, T2가 112%, T3가 79%로 조사되었다. 경제성, 수량 및 생물학적 효율을 고려해볼 때 18% 건조 수확후배지를 사용한 T2가 느타리 재배배지로 가장 효율적인 것으로 조사되었다.

The design of non-precious electrocatalysts with low-cost, good stability, and an improved oxygen reduction reaction(ORR) to replace the platinium-based electrocatalyst is significant for application of fuel cells and metal-air batteries with high energy density. In this study, we synthesize iron-carbide(Fe3C) embedded nitrogen(N) doped carbon nanofiber(CNF) as electrocatalysts for ORRs using electrospinning, precursor deposition, and carbonization. To optimize electrochemical performance, we study the three stages according to different amounts of iron precursor. Among them, Fe3C-embedded N doped CNF-1 exhibits the most improved electrochemical performance with a high onset potential of −0.18 V, a high E1/2 of −0.29 V, and a nearly four-electron pathway (n = 3.77). In addition, Fe3C-embedded N doped CNF-1 displays exellent long-term stabillity with the lowest ΔE1/2= 8 mV compared to the other electrocatalysts. The improved electrochemical properties are attributed to synergestic effect of N-doping and well-dispersed iron carbide embedded in CNF. Consequently, Fe3C-embedded N doped CNF is a promising candidate for non-precious electrocatalysts for high-performance ORRs.

정삼투 여과막(FO) 기술 분야는 해수 담수화에서 이미 다양한 연구가 진행되었으나, 하폐수 처리 분야의 적용에서는 상대적으로 많은 연구가 필요한 상황이다. FO 기술은 비 다공성 특성막과 각 용액 사이의 삼투압 차이를 이용하여 원폐수로부터 수분을 비롯하여, 질소-인과 같은 이온성 물질까지 분리할 수 있다. 본 연구에서는 FO 막을 혐기성 유동상 미생물반응기(AFBR)를 통해 처리된 처리수 내 존재하는 질소(주로 암모니아성 질소)를 제거하기 위해 적용되었다. 유도용액(Draw Solution, DS)의 종류(NaCl, CaCl2, Na2CO3)에 따라 투과량은 NaCl, CaCl2, Na2CO3 순으로 높게 나타났으며, 암모니아성 질소의 배제율은 각각 42.25%, 78.83%, 70.35%으로 나타났다.

The existing ethyl formate fumigant is carbon dioxide (CO2) mixed liquified gas in metal cylinder, but this product type costs a lot to manufacture, translate and maintain cylinder. To supplement these problems, we have developed a new ethyl formate fumigation technique with nitrogen (N2) carrier. We assessed the susceptibility of mealy bugs, the most frequently detected pests in imported banana, and phytotoxicity of banana fruits. Ethyl formate and nitrogen were concurrently treated on citrus mealybug, one of the most resistant mealybug to fumigant, and ethyl formate was treated with LC50 product of independent treatment dosage. Nitrogen was treated with 7 dosages from 79% to 95% concentration. Phytotoxicity of banana was assessed by treating EF 35 mg/L with N2 79% for 14 days, and color, sugar contents and loss of weight were measured. EF with N2 treatment showed more than 50% of mortality on every growth stages, and there was no significant difference between control and treatment banana fruits. These results indicate that concurrent treatment of EF and N2 can be used to control mealybug in banana fruits.

Soil is the main nitrogen (N) provider for plants but N in soil is not all available to advanced plants. Mineralization is a critical biological process for transferring organic N to inorganic N that can be used by plants directly. To investigate the effect of different levels of soil temperature and water content to soil mineralization, a field experiment was established on three different sites (A, B and C). We measured soil temperature, moisture and electrical conductivity once daily after swine slurry application. Average soil moisture and temperature in site A is the highest among three sites (40.9% and 9.7°C, respectively). Following is in site C (37.3% and 9.6°C) and the lowest is in site B (28.0% and 9.0°C). Ammonium N (NH4+-N) and nitrate N (NO3--N) were determined on the first and fifth day after treatment. Compared with site B and C, site A always had the highest soil total N content (1.54 g N kg-1 on day one; 1.22 g N kg-1 on day five) and highest NO3-- N content (93.18 mg N kg-1 on day one; 16.22 mg N kg-1 on day five) and a significant decrease on day five. Content of NH4+-N in site B and C reduced while in site A, it increased by 6.7%. Results revealed that net N mineralization positively correlated with soil temperature (P<0.5, r=0.675*) and moisture (P<0.01, r=0.770**), suggesting that to some extent, higher soil moisture and temperature contribute more to inorganic N that can be used by plants.

본 연구는 느타리버섯 수확후배지를 배지자원으로 재사용하기 위하여 미생물처리에 의한 수확후 배지의 총질소함량 증진효과를 조사하였다. Bacillus sp. GM20-4 와 Rhodobacter sphaeroides(RS) 배양액 30%를 함께 접종하여 5일간 상온에서 배양 시 총질소 함량이 가장 크게 증가하였다. 농가의 수확후배지 조성에 따른 GM20-4와 RS 처리에 의한 T-N함량 변화를 조사하기 위하여 경기 지역 버섯재배농가 세 곳의 수확후배지(spent mushroom substrates, SMS A, B, C)를 수집하여 GM20-4 와 RS 배양액 30%를 처리한 결과, 무처리구에 비해 건조 SMS B 에서 T-N함량이 20%p로 가장 크게 증가하였고, 건조 SMS A는 17%, C는 12% 증가하였다. 반면에 생수확후 배지에서는 미생물 처리에 의한 T-N 함량 증가 효과가 크지 않았다. 또한 아미노산 조성별 함량 변화는 건조된 SMS A, B, C 모두 GM20-4와 RS 처리로 aspatic acid와 glutamic acid가 상대적으로 높게 증가한 결과를 보였고, 특히 건조 SMS B의 처리구에서 두 아미노산의 함량이 무처리구보다 2.9배 증가를 보임으로서 미생물처리가 수확후배지의 총질소 및 아미노산 함량의 증진효과를 확인하였다.

To investigate the impact of nitrogen (N) mineral on reproductive potential of Brassica napus L, plants were treated with different levels of N treatment (N0; N100; N500). The half of N content for each treatment were applied at the beginning of the early vegetative stage and the rest was applied at the late vegetative stage. Nitrogen content in plant tissues such as root, stem and branch, leaf, pod and seed was analyzed and harvest index (HI) was calculated as percentage of seed yield to total plant weight. Biomass and nitrogen content were significantly affected by different levels of N supply. Biomass was significantly decreased by 59.2% in nitrogen deficiency (N0) but significantly increased by 50.3% in N excess (N500), compared to control (N100). Nitrogen content in all organs was remarkably increased with nitrogen levels. N distribution to stem and branches, and dead leaves was higher in N-deficient (N0) and N excessive plants (N500) than in control (N100). However, nitrogen allocated to seed was higher in control (N100) than in other treatments (N0 or N500), accompanied by higher HI. These results indicate that the optimum level of N supply (N100) improve HI and N distribution to seed and excessive N input is unnecessary.