한라산 아고산대 구상나무군락의 물질생산과 탄소수지

장래하 ( Rae Ha Jang ),최재윤 ( Jae Yun Choi ),유영한 ( Young Han You ) 한국환경생태학회 2014 한국환경생태학회 학술대회지 Vol.2014 No.2

본 연구는 우리나라 한라산 아고산대에서 구상나무림의 물질생산, 탄소분포와 탄소수지에 대하여 알아보기 위해 수행되었다. 구상나무림의 현존량은 2009, 2010, 2011, 2012 와 2013에 각각 98. 88, 106. 42, 107. 67, 108. 31와 91. 48ton/ha 유기탄소량은 44. 5, 47. 89, 48. 45, 48. 74와 41. 17 ton C/ha 이었다. 순생산량은 2009, 2010, 2011, 2012 년에 각각 11. 40, 7. 41, 0. 05 와 -9. 46 ton ha-1yr-1 이었고, 유기탄소 순생산량은 5. 13, 3. 33, 0. 02와 -4. 25 ton C ha-1yr-1 이었다. 2009~2013년 연간 낙엽생산량은 각각 2. 42, 4. 02, 2. 94, 5. 47, 2. 67 ton ha-1yr-1이었고, 낙엽생산량의 유기탄소량은 1. 09, 1. 80, 1. 32, 2. 46, 1. 20 ton C ha-1yr-1. 연간 임상낙엽량 6. 09, 5. 40, 4. 45, 2. 57 ton/ha 임상냑엽량의 유기탄소량은 2. 74, 2. 43, 2. 00, 1. 16 ton C/ha. 토양 20cm까지의 유기탄소축척량은 각각 55. 77, 54. 90, 50. 69, 44. 42, 41. 87 ton C ha-120cm-1. 2012년 토양호흡을 통해 배출된 유기탄소량은 2011, 2012년에 각각 4. 42, 4. 14 ton Cha-1yr-1 이었다. 한라산 구상나무림에서는 2011년에 총 0. 01 ton C ha-1yr-1의 유기탄소를 대기로 방출하였고 2012년에 -8. 39 ton C ha-1yr-1의 유기탄소를 대기로 배출하였다.

맥주박 바이오차 처리가 암모니아 배출량에 미치는 영향 평가

이재한(Jae-Han Lee),최하연(Ha-Yeon Choi),박성용(Seong-yong Park),천진혁(Jin-Hyuk Chun),강윤구(Yun-Gu Kang),윤여욱(Yeo-Uk Yun),이기범(Gibum Yi),오택근(Taek-Keun Oh) 한국토양비료학회 2021 한국토양비료학회 학술발표회 초록집 Vol.2021 No.11

암모니아(NH₃)는 대기 중 황산화물(SOx), 질소산화물(NOx) 등과 반응하여 황산암모늄, 질산암모늄과 같은 2차 미세먼지를 생성하는 주요 미세먼지 원인물질이다. 2017년 기준 국내에서 NH₃는 총 308,298 ton year<SUP>-1</SUP> 배출되었으며, 농업부문에서 약 79.3%의 비율로 가장 많이 배출되었다. 토양에 질소질 비료의 시용 시 발생되는 NH₃의 대기로 배출은 토양 내 질소 손실의 원인이 되기도 한다. 바이오차는 넓은 표면적과 표면의 작용기를 가지고 있어 토양 내에서 중금속이나 오염물질 등을 제거하는 특징이 있다. 본 연구는 다양한 온도에서 열분해된 맥주박 바이오차 처리가 NH₃ 배출량에 미치는 영향을 평가하기 위해 실시하였다. 바이오차는 충분히 건조된 맥주박을 300, 500, 700°C에서 각각 1시간 동안 열분해하여 제조하였다. 각 바이오차를 토양에 3% (w w<SUP>-1</SUP>)씩 혼합 후 NH₃ 포집을 위해 자체 제작한 아크릴컬럼에 작토층 높이인 20 cm 까지 토양을 채웠으며, 토양 수분함량은 20%로 조절하였다. 질소질 비료는 작물별 시비처방기준의 배추를 기준으로 요소를 각 처리구에 320 kg ha<SUP>-1</SUP>로 처리하였다. NH₃의 포집은 요소 처리 후부터 약 30일간 실험실 내에서 실시하였다. 배출되는 NH₃는 0.05 N H₂SO₄으로 포집하여, Indophenol blue method로 비색정량하였다. 그 결과, 시험 기간 중 총 NH₃ 배출량은 BB<SUB>700</SUB>처리구가 약 11.83 kg ha<SUP>-1</SUP>로 가장 높게 나타났다. BB<SUB>300</SUB>처리구의 총배출량은 약 7.34 kg ha<SUP>-1</SUP>로 가장 낮았으며, N처리구에 비해 약 30.5% 저감 되었다. BB<SUB>700</SUB>처리구는 N처리구에 비해 NH₃ 총배출량이 약 12% 증가하였는데, 이는 바이오차의 높은 pH에 의한 alkali effect로 판단된다. 실험 후 토양 분석 결과, 모든 바이오차 처리구에서 pH, EC, Av. P₂O<SUB>5</SUB>, T-C, T-N 등이 증가하였다. 특히, BB<SUB>700</SUB>처리구는 처리된 바이오차의 높은 탄소 함량으로 인하여, 토양 내 탄소 함량이 약 3.44%로 가장 높았다. 따라서, 비교적 낮은 온도에서 열분해한 BB<SUB>300</SUB>의 토양 처리가 농경지에서 배출되는 NH₃를 감축할 수 있으며, 본 연구 결과는 실제 농경지에서 배출되는 NH₃를 감축하기 위한 기초자료로 사용될 수 있을 것으로 판단된다.

수피 돈분 부산물 비료의 부숙단계별 분광학적 특성 변화

양재의(Jae E . Yang),박창진(Chang Jin Park),신명교(Myung Kyo Shin),박용하(Yong Ha Park),최문헌(Moon Heon Choi),김정규(Jeong Gyu Kim),김정제(Jeong Je Kim) 한국환경농학회 1999 한국환경농학회지 Vol.18 No.4

Changes of the spectroscopic characteristics of the organic matter fractions and circular filter paper chromatograph were assessed for the bark and piggery manure composts during the composting. as an approach to base the criteria of the compost maturity evaluation. Contents of humic acid-C (HA-C) and fulvic acid-C (FA-C) in both bark and piggery manure composts were decreased as the composting got closer to maturity, but the ratios of HA-C/FA-C were increased. During the composting. Δlog K values were decreased, but RF values were increased. Humic acid of the mature bark compost after 120 days of composting was A-type, as compared to Rp-type for the raw bark and B-type for the immature compost. However. humic acid of the mature piggery manure composts after 40 days of composting was B-type, indicating the humification of the organic matter fractions continued at this stage. Circular filter paper chromatograph of the mature bark compost exhibited the regular sawteeth pattern at the edge, but that of the mature piggery manure showed an irregular sawteeth pattern. Results demonstrated that spectroscopic characteristics and circular filter paper chromatograph of the organic by-product composts might be employed for the compost stability assessment.

열공형과 비열공형 피질하 혈관성 치매에서 위험인자의 차이에 관한 비교 연구

배희준,정지향,유경호,나덕렬,김상윤,최경규,양동원,손의주,이상도,김재우,박경원,김응규,이재홍,박미영,한일우,함동석,최문성,하충건,최성혜,이애영,이병철,한설희 대한치매학회 2003 Dementia and Neurocognitive Disorders Vol.2 No.2

Backgrounds and Objectives: Vascular dementia is a group of dementing disoders arising from various stroke syndrome. Among these. subcortical ischemic vascular dementia (SIVD) is regarded as a relatively distinct clinical entity. However, MRI patterns of SIVD are not homogenous. In some patients, lacunes are dominant, and in others, subcortical white matter changes are. This study was designed to compare risk factor profiles between SIVD with and without multiple lacunes. Methods: We divided 47 subjects (22 males, mean age. 68 years) recruited from VADAPET (Multicenter Trial For Evaluation Of The Changes In the PET Images Of Subcortical Vascular Dementia Patient) study into two groups one with more than 5 lacunes in deep gray matter (lacune group) and the other with 5 or less(non-lacune group) Clinical characteristics and laboratory findings of two groups were compared. Results: Nineteen of 47 patients (40%) belonged to the lacune group. The lacune and non-lacune groups d d not differ in the following variables: age, hypertension, diabetes mellitus, hyperlipidemia heart disease, history of stroke or TIA, history of trauma or major surgery, family history of hypertension stroke, or dementia, age at diagnosis of dementia, body mass index, white blood cell count, ESR, CRP, fibrinogen, hemoglobin A1C, total cholesterol. LDL cholesterol creatinine, proteinuria, glucosuria, and microhematuria. However, male sex, smoking alcohol. hemoglobin, and HDL cholesterol were possibly associated more with lacune group SIVD than with non-lacune group (p<0 1) Multivariate analyses revealed that smoking, hemoglobin, and HDL cholesterol were independent predictors of SIVD with multiple lacunes Conclusion: Our study suggests that SIVD with multiple lacunes may be significantly different in smoking habits hemoglobin, and HDL cholesterol from SIVD without multiple lacunes.

Sodium–Metal Halide and Sodium–Air Batteries

Ha ,, Seongmin,Kim ,, Jae‐,Kwang,Choi, Aram,Kim, Youngsik,Lee, Kyu Tae WILEY‐VCH Verlag 2014 ChemPhysChem Vol.15 No.10

<P>Impressive developments have been made in the past a few years toward the establishment of Na-ion batteries as next-generation energy-storage devices and replacements for Li-ion batteries. Na-based cells have attracted increasing attention owing to low production costs due to abundant sodium resources. However, applications of Na-ion batteries are limited to large-scale energy-storage systems because of their lower energy density compared to Li-ion batteries and their potential safety problems. Recently, Na-metal cells such as Na-metal halide and Na-air batteries have been considered to be promising for use in electric vehicles owing to good safety and high energy density, although less attention is focused on Na-metal cells than on Na-ion cells. This Minireview provides an overview of the fundamentals and recent progress in the fields of Na-metal halide and Na-air batteries, with the aim of providing a better understanding of new electrochemical systems.</P>

고속 처리용 문자 특징의 성능 비교

최원호,최재하 울산대학교 1991 공학연구논문집 Vol.22 No.1

DSP 소자등을 사용하여 문자 인식 시스템을 구성하는 경우에 연산량, 인식률의 측면에서 사용 가능한 특징들의 성능을 비교하여 보았다. 비교된 특징들은 메쉬(mesh)와 receptive field를 달리하는 몇 종류의 방향성 에지 연산자들이다. 이 특징들을 문자 인식에 적용하여 본 결과, 메쉬 보다는 방향성 에지 연산자들의 인식률이 높았으며, receptive field를 작게 하여 특징 벡터의 크기를 크게한 것이 인식률이 좋아지지만 연산량은 늘어나게 되어 시스템 구성에 부담이 된다. 본 논문에서 선택한 적절한 특징은 수평 방향의 receptive field, 수직 연산자에 수직 방향의 receptive field를 적용한 것으로서, 이들은 벡터 크기와 인식률에서 적절한 것으로 판단된다. The performance of mesh and directional edge operator with different receptive fields, that are thought acceptable in the recognition rate and tin the amount of arithmetic operation, are compared. These features are for high-speed character recognition systems based on DSP components. The results we got from the experiments of character recognition are as follows. The recognition rate of the directional edge operator is superior to that of the mesh. The directional edge operator with small receptive field explores better recognition rate than the operators with other receptive fields, but the vector size of the former becomes twice of the latter. It means the increasing of the amount of arithmetic operation. As a result, the appropriate feature among the features we tested for high speed character recognition is the mixed feature of horizontal and vertical operator with horizontal and vertical receptive field, respectively.

중간세공탄소를 담체로 사용한 직접메탄을 연료전지용 Pt/C 촉매제조

하승백,김현수,최재식,정원섭,이호인 한국공업화학회 2003 응용화학 Vol.7 No.2

For the direct methanol fuel cell, the expensive cost of Pt is one of the most important factors. In this study, various kinds of support were synthesized and chosen for highly dispersed catalysts which need less amount of Pt and show higher activity. A mesoporous carbon was selected as a support which has 5 times larger specific surface area than Vulcan XC-72, a commercial support. Such a large surface area gave an advantage in the dispersion of Pt, but a disadvantage in electric conductivity which could be solved by increasing the carbonizaton temperature in the preparation of mesoporous carbon. These prepared mesoporous carbons were used as supports of Pt. Among the catalysts, the catalyst using mesoporous carbon carbonized at 1000 ℃ showed better activity than the catalyst using Vulcan XC-72 as a support showing the best activity. From the XRD analysis, the activity was proportional to the dispersion of Pt.

대구시 도심의 접근특성과 가로이용특성에 관한 연구

최영은,하재명 대한건축학회 2003 대한건축학회논문집 Vol.19 No.5

The purpose of this study is to examine the access characteristics of people visiting at the urban street and district. In this study, the access characteristics were classified into three factors, a access method, a visiting aim and a visitor's character. The case study areas were selected the nine streets and districts which crowded with stores dealing with similar goods in Daegu CBD. The results of the case study has been summarized as follows; Firstly, in the individual districts dealing with a specific goods, the access characteristics appeared differently. Secondary, the visitors' visiting aim in the case study areas affected the selection of a access method. Thirdly, the street behavior according to a operational situation appeared differently. And in the interview with visitors, the subjects answered that the urgent problems in the case areas are the traffic confusion and the shortage parking space.

영양소제거 공정의 기질 정량관계에 대한 온도와 기질부하의 영향

하준수,최의소,박재홍,길경익,김성원 대한상하수도학회 2003 상하수도학회지 Vol.17 No.6

This research has been performed to evaluate the stoichiometric relationship between removed COD and nitrogen or phosphorus. A modified A²/O process, which was equipped with an external nitrification tank and a switching reactor, was operated with a capacity of 50㎥/d. From the results, it has been concluded that the stoichiometric values were varied by temperature condition or input COD loads. In case of denitirfication, the requirement g COD for removed nitrate nitrogen ranged 0.13 to 10.5g, and the compensation coefficient of temperature was evaluated as 1.028. For phosphorus removal, the required COD was about 7.5gCOD_(consumed)/gP_(released) and 0.54gPHACOD_(storage)/gP_(uptake). During rainy season, as it appeared a lower organic substrate loads, the PHA(Poly Hydroxy Alkanoate) contents of biomass was reduced. From the relationship between influent BOD, and the sum of removed TN and TP, the ratio for rainy and winter season was about 4.8 and 5.8g BOD/g (TN+TP) each others. Therefor, the substrat ratios for nitrogen and phosphorus removal appeared to be affected by temperature and influent organic substrate loads.

PCRNN을 이용한 음향신호 식별에 관한 연구

최재하,안종구 울산대학교 1993 공학연구논문집 Vol.24 No.1

파워스펙트럼은 디지탈신호처리 분야에서 널리 이용되어 왔으나 해석하고자 하는 신호의 위상에 관한 정보를 잃어 버리는 단점이 있어서, 위상에 관한 정보를 필요로 하는 경우에는 파워스펙트럼 해석법은 그 이용에 제약을 받는다. 바이스펙트럼은 그 계산에 시간이 많이 걸리는단점은 있으나 반면에 위상에 관한 정보를 잃지 않는 장점이 있다. 본 논문에서는 여러가지 자동차들의 엔진 음향을 녹음하여 바이스펙트럼을 구한 후, 부분결합 회귀신경회로망을 이용하여 바이스펙트럼 패턴을 식별하고 결과적으로 신호원을 식별하는 방법에 관하여 연구하였다. Power spectrum has been widely utilized in the digital signal processing area. However, there is no information about the phase of a signal, the power spectral analysis technique can not be used to interpret the phase coherency of the signal produced by some nonlinear process. In this case, the third-order higher-order spectrum, the so called bispectrum, is very useful in analyzing such signals. In this paper, the bispectra of the measured acoustic signals of vehicles are computed and then the PCRNN(partially connected recurrent neural netwok) is used in order to identify the acoustic signal sources using the bispectrum patterns.