• 한국환경농학회지
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• 제38권4호
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• pp.332-337
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• 2019

BACKGROUND: From year 2005, landfill for food waste has been prohibited. Also, according to London agreement in year 2013, ocean discharge for livestock manure, sewage sludge, and food waste has been regulated. Alternative way for food waste disposal is incineration. However, due to high moisture content, additional input for energy is needed. Therefore, effective way for food waste disposal such as application of food waste compost is needed. METHODS AND RESULTS: Seven different treatments (livestock compost, food waste compost, food waste + livestock compost, livestock compost + chemical fertilizer, food waste compost + chemical fertilizer, food waste + livestock compost + chemical fertilizer and control) were applied to tomato crop. All treatments were replicated with completely randomized design. Tomato growth treated with LC+NPK showed the highest values at 6 weeks for all parameters such as leaf length (11.80 cm), leaf width (6.88 cm), and chlorophyll (61.12 O.D.), compared to other treatments. Subsequently the FWC+LC+NPK treatment was followed (11.51 cm, 6.40 cm, 59.50 O.D. for leaf length, leaf width, and chlorophyll, respectably). EC, OM contents, and CEC in the soil treated with the composts significantly increased. CONCLUSION: To evaluate the effect of food waste compost application on tomato growth and soil chemical properties, we carried out field experiment treated with 7 treatments with 3 replicates. The LC+NPK treatment showed highest values for all parameters. Some parameters such as shoot length and total length for tomato were not significantly different between the LC+NPK and the FWC+LC+NPK treatments.

• 대한기계학회논문집B
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• 제38권7호
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• pp.589-594
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• 2014

전기자동차와 하이브리드 자동차의 상용화에 따라 전기용량과 에너지 밀도가 향상된 리튬 이온 전지의 개발이 필요하다. 본 논문에서는 상장 모델을 이용하여 5산화 바나듐으로 구성된 다공성 구조물로의 리튬 이온 삽입현상을 분석하였다. 다공성 5산화 바나듐 구조물은 구멍을 갖는 구체의 구조물로 정의하였으며, 이때 구멍의 형상은 원통형이다. 원통형 구멍의 반지름, 깊이 및 개수를 조절하여 다양한 다공성 5산화 바나듐의 미세조직 형상을 고려하였으며, 각 미세조직의 형상인자와 구조물에 삽입되는 리튬 이온의 개수 사이의 관계를 분석하였다. 마지막으로 최적화 작업을 통하여 가장 많은 수의 리튬 이온이 삽입될 수 있는 다공성 5산화 바나듐의 구조체 형상을 찾아내었다.

• 상하수도학회지
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• 제23권4호
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• pp.447-458
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• 2009

Energy loss at manholes, often exceeding friction loss of pipes under surcharged flow, is considered as one of the major causes of inundation in urban areas. Therefore, it is necessary to analyze head loss at manholes, especially in case of surcharged flow. Hydraulic experiments were conducted with three cases. Case A is to test whether the shapes of the manholes influence head loss coefficients. Case B and C were proposed to further reduce head losses by improving the manhole hydraulic efficiency. In case B, the joining part of the pipe at both shapes of manholes is shifted from central part to side part. The test in case C is to check the average head loss coefficient by installing the side benching in square manhole, based on shifted joining part model. The average head loss coefficient for circular and square manhole on case A was 1.6. This did not show much difference of the head loss coefficients in spite of the discharge variation in this case. However, case B and C show large difference between head loss coefficients due to the strong oscillation of water surface and the horizontal swirl motion. The circular and square manholes in case B reduced the head loss by 30% and 6% than ones in case A, respectively. The average head loss coefficient for circular manhole in case B was 1.1. Case C reduced average loss coefficients of the square manhole in case A from 1.6 to 1.1. Accordingly, the circular manhole in case B and the square manhole in case C showed the effective way to reduce the head loss. These head loss coefficients could be available to apply to the urban sewer system with surcharged flow.

• International Journal of Fluid Machinery and Systems
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• 제2권2호
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• pp.165-171
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• 2009

We developed a 'multi-point vibration acceleration method' for accurately predicting the cavitation intensity in pumps. Pressure wave generated by cavitation bubble collapse propagates and causes pump vibration. We measured vibration accelerations at several points on a casing, suction and discharge pipes of centrifugal and mixed-flow pumps. The measured vibration accelerations scattered because the pressure wave damped differently between the bubble collapse location and each sensor. In a conventional method, experimental constants are proposed without evaluating pressure propagation paths, then, the scattered vibration accelerations cause the inaccurate cavitation intensity. In our method, we formulated damping rate, transmittance of the pressure wave, and energy conversion from the pressure wave to the vibration along assumed pressure propagation paths. In the formulation, we theoretically defined a 'pressure propagation coefficient,' which is a correlation coefficient between the vibration acceleration and the bubble collapse pressure. With the pressure propagation coefficient, we can predict the cavitation intensity without experimental constants as proposed in a conventional method. The prediction accuracy of cavitation intensity is improved based on a statistical analysis of the multi-point vibration accelerations. The predicted cavitation intensity was verified with the plastic deformation rate of an aluminum sheet in the cavitation erosion area of the impeller blade. The cavitation intensities were proportional to the measured plastic deformation rates for three kinds of pumps. This suggests that our method is effective for estimating the cavitation intensity in pumps. We can make a cavitation intensity map by conducting this method and varying the flow rate and the net positive suction head (NPSH). The map is useful for avoiding the operating conditions having high risk of cavitation erosion.

• Nano
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• 제13권12호
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• pp.1850141.1-1850141.11
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• 2018

Sodium ion batteries based on the more sodium source reserve than that of lithium have been designed as promising alternatives to lithium ion batteries. However, several problems including unsatisfied specific capacity and serious cyclic stability must be solved before the reality. One of the effective approaches to solve the abovementioned problems is to search for suitable anode materials. In this work, we designed and prepared $FeSe_2$ nanoflakes via a simple hydrothermal method which can be adjusted in composition by Fe precursor. As a potential anode for sodium storage, the optimized $FeSe_2$ electrode was further evaluated in different electrolytes of $NaClO_4$ in propylene carbonate/fluoroethylene carbonate and $NaCF_3SO_3$ in diethylene glycol dimethyl ether. The capacity was about $470mAh\;g^{-1}$ and $535mAh\;g^{-1}$ at $0.5A\;g^{-1}$, respectively, in the voltage between 0.5 V and 2.9 V in the cycle of stabilization phase. Superior performance both in capacity and in stability was obtained in ether-based electrolyte, which affords the property without plugging the intermediates of transition metal dichalcogenides during charge/discharge processes.

• Tribology and Lubricants
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• 제37권6호
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• pp.246-252
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• 2021

Among the engine components of an internal combustion engine, the valve train is a series of systems that supply intake gas to the combustion chamber and operate intake and exhaust valves that discharge exhaust gas. If excessive wear occurs in the valve train system, the suction and exhaust valves do not open and close on time, which leads to abnormal combustion and exhaust gas. In this study, we conduct experiments and analyses on friction and wear characteristics of the valve train system. Moreover, we experimentally study the correlation between the pinball and pinball cap on engine oil lubrication, friction experiment, wear amount analysis, and surface analysis. Specifically, we experiment using Ball on reciprocating tribo-tester and apply commercial engine oil sold on the market engine oil. We construct the experimental conditions for each new oil and oil. Accordingly, the completed specimen was subjected to a confocal microscope to check the wear volume, observe the surface of the specimen, and confirm the elemental components using a scanning microscope (SEM) and an energy dispersion X-ray spectrometer (EDS). Through this experiment, we analyze the friction and wear characteristics of valve train components according to engine oil grade, and the obtained data serve as an effective engine oil management method.

• 한방안이비인후피부과학회지
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• 제16권1호
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• pp.42-62
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• 2003

Subjects : We tried to analysis dermatosurgical prescriptions including 477 WonBang(元方) prescriptions for SangJungHaTong(上中下統) introduced by HwangDoYeon(黃道淵). Methods : Prescriptions in BangYakHapPyun(方藥合編) is generally categorized into SangTong(上統), JungTong(中統), HaTong(下統) which are called PoJe(補劑), HwaJe(和劑), KongJe(功劑) respectively. This study classified and analyzed major diseases and symptoms appeared in dermatosurgical prescription and composition of medicine, as well as in BangYakHapPyun(方藥合編). Results and conclusions : The results of examining dermatosurgical prescriptions in WonBang(元方) of SangJungHaTong(上中下統) in BangYakHapPyun(方藥合編) are as follows; 1. The proportion of dematosurgical prescriptions was SangTong(上統) $\frac{10}{126}$(7.9$\%$). JungTong(中統) $\frac{22}{181}$(12.1$\%$), and HaTong(下統) $\frac{16}{163}$(9.8$\%$), which means that JungTong(中統)(HwaJe 和劑) takes up relatively the largest portion. 2. As for SangTong(上統), upper level herbs used in medicine are Glycyrrhiza uralensis(甘草), Paeonia japonica(白芍藥), Angelica gigas(當歸). Astragalus membranaceus(황기). Ginseng(人蔘), Poria cocos(복령), Atractylodis macrocephalae rhizoma(白朮). Cinnamon(肉桂), Rehmaniniae radix preparat(熱地黃). And these herbs are the components of Sipjundaebo-tang(十全大補湯), one of the most well-known medicine for weak energy and blood(補氣血). 3. As for JungTong(中統), in addition to medicine for weak energy and blood. Ledebouriella seseloides(防風) that removes ill elements on skin surface and Pung(風) called "wind". Limonium tetragonum(桔梗) that eliminates discharges and sputum, Angelica dahurica(白芷) that removes discharge and suppress tumor are applied. Other herbs are Ostericum koreanum(羌活). Skullcap(황령),Schizonepeta tenuifolia(荊芥), Aurantii fructus(地殼), Cimicifuga heracleifolia(升麻), Bupleurum falcatum(柴胡), Lonicerae flos(金銀花). These herbs are more effective for wind-calming treatment. cooling down fever, clearing skin irritation, detoxication. removal of tumor and discharge than replenishing energy and blood. 4. As for HaTong(下統), Angelica gigas(當歸) and Ledebouriella seseloides(防風), the two major herbs for SangTong(上統) and JungTong(中統), are mostly used. In addition, Skullcap(黃芩), Gardenia jasminoides(梔子), Eisenia bicyclis(大黃) are other major components and their key efficacy is to lower fever and KongHa(功下). 5. Herbs applied for SangTong(上統), JungTong(中統), and HaTong(下統) in large quantity are Glycyrrhiza uralensis(甘草) that harmoniously combine different herbal elements and Poria cocos(복령) that discharges humidity and watery elements out of body, removes humid and hot elements, and strengthen gastrointestinal system. Based on this, it is inferred that prescriptions for this study focus largely on treatment of humid and hot elements. In the composition of this prescription, Angelica gigas(當歸), Paeonia japonica(白芍藥), and Cnidium officinale(川芎) are taking up relatively large proportion, which are basic herbs for Samul-tang(四物湯). Therefore, it is incurred here that the concept of "replenishing blood" bears importance in dermatosurgical treatment. 6. As for herb medicines used for more than two types of prescriptions of SangTong(上統), JungTong(中統), and HaTong(下統), most of them are simultaneously used for SangTong(上統) and JungTong(中統), or for JungTong(中統), and HaTong(下統) except for Atractylodis macrocephalae rhizoma(白朮) and Gleditsia sinensis(조각자). This finding implies that prescription or treatment that are simultaneously applied are replenishing and harmonizing, or harmonizing and attacking while replenishing and attacking never go together.

• 한국가스학회지
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• 제20권2호
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• pp.1-9
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• 2016

본 연구는 플라즈마/촉매 공정을 이용하여 n-헵테인과 일산화탄소의 동시제거에 대해 조사하였다. n-헵테인과 일산화탄소의 분해특성을 파악하기 위해 플라즈마/촉매 공정과 촉매공정의 분해효율을 비교하였고, 촉매의 종류, 온도, 전력 등을 변화시켜 실험을 진행하였다. n-헵테인의 분해효율은 반응기 내부의 온도보다는 에너지밀도에 더 영향을 많이 받는 것으로 확인되었으며, 일산화탄소는 에너지밀도와 반응기 내부 온도 모두의 영향을 받는 것으로 나타났다. 촉매의 종류를 달리하며 n-헵테인의 분해효율을 조사한 결과 $Pd/{\gamma}-Al_2O_3$ > $Ru/{\gamma}-Al_2O_3{\approx}Ag/{\gamma}-Al_2O_3$순으로 나타났다. 특히, $Pd/{\gamma}-Al_2O_3$를 사용한 경우 n-헵테인 분해 과정에서 일산화탄소가 거의 발생하지 않았으며, $CO_2$ 선택도가 100%에 가까웠다. 일산화탄소 분해효율은 $Pd/{\gamma}-Al_2O_3$ > $Ru/{\gamma}-Al_2O_3$ > $Ag/{\gamma}-Al_2O_3$ 순으로 나타났으며, $180^{\circ}C$이하의 온도에서는 플라즈마/촉매 공정의 효율이 높고, $180^{\circ}C$이상에서는 촉매 공정의 분해효율이 높았다.

• Nuclear Engineering and Technology
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• 제14권4호
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• pp.186-195
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• 1982

SYSRAN code를 사용하여 고리 1호기의 중기배관파열사고를 분석하였다. SYSRAN code는 중성자출력과 열선속계산은 각각 점근사 중성자 운동방정식과 집중정수 모형을 이용하고 냉각수 계통 과도현상에 대해서는 전 계통을 균일한 압력으로 취급하여 질량 및 에너지 평형방정식을 이용하여 계산한다. 사고 결과를 심각하게 만드는 노심상태로 부냉각재 온도계수가 커지는 노심말기와 증기발생기의 유체함량이 가장 많은 고온 정지상태를 호기조건으로 하여, 격납용기외부의 가장 큰 배관면적인 1.4f $t^2$ 크기의 증기배관이 파열되었을때 Moody critical flow model에 따라 증기가 방출된다고 가정하여 분석하였다. 그 결과 노심의 최대 열선속은 사고후 60초에 정상상대의 38%로서 FSAR의 26%에 비해 높은 값을 나타냈으나 모든 과도현상의 경향은 FSAR의 결과와 잘 일치하였다. 민감도 조사결과 이 사고는 냉각재밀도 계수와 노심 하부공간혼합인자에 가장 민감한 것으로 나타났다. B bank중 한 개의 RCCA가 완전인출 상태에서 노심에 삽입되지 않았다고 가정했을 경우의 FSAR 분석결과인 $F_{$\Delta$H}$를 3.66으로 Fz를 1.55로 하여 DNBR을 계산해 본 결과, 최소 DNBR은 1.62가 되어 핵연료의 손상은 예상되지 않았다. 점근사중성자 운동방정식, 집중 정수모형 및 질량과 에너지평형 방정식을 이용한 계통 과도 현상모델은 발전소 전 계통의 과도 현상의 경향을 연구하는데 적합한 것으로 밝혀졌다.구하는데 적합한 것으로 밝혀졌다.

• Journal of Periodontal and Implant Science
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• 제51권3호
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• pp.213-223
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• 2021

Purpose: The atmospheric pressure plasma jet (APPJ) has been introduced as an effective disinfection method for titanium surfaces due to their massive radical generation at low temperatures. Helium (He) has been widely applied as a discharge gas in APPJ due to its bactericidal effects and was proven to be effective in our previous study. This study aimed to evaluate the safety and effects of He-APPJ application at both the cell and tissue levels. Methods: Cellular-level responses were examined using human gingival fibroblasts and osteoblasts (MC3T3-E1 cells). He-APPJ was administered to the cells in the experimental group, while the control group received only He-gas treatment. Immediate cell responses and recovery after He-APPJ treatment were examined in both cell groups. The effect of He-APPJ on osteogenic differentiation was evaluated via an alkaline phosphatase activity assay. In vivo, He-APPJ treatment was administered to rat calvarial bone and the adjacent periosteum, and samples were harvested for histological examination. Results: He-APPJ treatment for 5 minutes induced irreversible effects in both human gingival fibroblasts and osteoblasts in vitro. Immediate cell detachment of human gingival fibroblasts and osteoblasts was shown regardless of treatment time. However, the detached areas in the groups treated for 1 or 3 minutes were completely repopulated within 7 days. Alkaline phosphatase activity was not influenced by 1 or 3 minutes of plasma treatment, but was significantly lower in the 5 minute-treated group (P=0.002). In vivo, He-APPJ treatment was administered to rat calvaria and periosteum for 1 or 3 minutes. No pathogenic changes occurred at 7 days after He-APPJ treatment in the He-APPJ-treated group compared to the control group (He gas only). Conclusions: Direct He-APPJ treatment for up to 3 minutes showed no harmful effects at either the cell or tissue level.