• 설비공학논문집
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• 제14권1호
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• pp.31-37
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• 2002

This paper is concerned with the development of a new method for making and separating ice and saving floated ice by installing an evaporation plate at in-water within a storage tank. In a conventional harvest-type ice storage system, a tank saves ice by separating a formed ice from an installed evaporation plate, which is located above an ice storage tank as an ice storage system. A new harvest-type method shows very good heat transfer efficiency than a convectional method. It is because the evaporation panel is directly contacted with water in a storage tank. Also, at a conventional system a circulating pump, a circulating water distributor and a piping are installed, but these components are not necessary in a new method. In this study two kinds of ice storage systems are experimentally investigated to study the thermal characteristics of ice storage tanks. The results showed discharge of cold capacity of new type indicated the high values about 30~40% based on five time of drive, the temperature difference of inlet/outlet occurred the big range about $1.3^{\circ}C$. So, the new type which makes ice in water showed superiorly.

• Journal of Biosystems Engineering
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• 제41권1호
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• pp.12-20
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• 2016

Purpose: Pepper prices have risen continuously because of a decrease in cultivation area; therefore, mechanical harvesting systems for peppers should be developed to reduce cost, time, and labor during harvest. In this study, a screw type picking head for a self-propelled pepper harvester was developed, and the optimal working conditions were evaluated considering helix types, winding directions of helix, and rotational speeds of the helix. Methods: The screw type was selected for the picking head after analyzing previous studies, and the device consisted of helices and a feed chain mechanism for conveying pepper branches. A double helix and a triple helix were manufactured, and rotational speeds of 200, 300, and 400 rpm were tested. The device was controlled by a variable speed (VS) motor and an inverter. Both the forward and reverse directions were tested for the winding and rotating directions of the helix. An experiment crop (cultivar: Longgreenmat) was cultivated in a plastic greenhouse. The test results were analyzed using the SAS program with ANOVA to examine the relationship between each factor and the performance of the picking head. Results: The results of the double and triple helix tests in the reverse direction showed gross harvest efficiency levels of 60-95%, mechanical damage rates of 8-20%, and net marketable portion rates of 50-80%. The dividing ratio was highest at a rotational speed of 400 rpm. Gross harvest efficiency was influenced by the types of helix and rotational speed. Net marketable portion was influenced by rotational speed but not influenced by the type of helix. Mechanical damage was not influenced by the type of helix or rotational speed. Conclusions: Best gross harvest efficiency was obtained at a rotational speed of 400 rpm; however, operating the device at that speed resulted in vibration, which should be reduced.

• Journal of Biosystems Engineering
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• 제38권1호
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• pp.18-24
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• 2013

Purpose: This study was conducted to develop an optimal combine scheduling program using Max-Coverage algorithm which derives the maximum efficiency for a specific location in harvest seasons. Methods: The combine scheduling program was operated with information about combine specification and farmland. Four operating types (Max-Coverage algorithm type, Boustrophedon path type, max quality value type, and max area type) were selected to compare quality and working capacity. Result: The working time of Max-Coverage algorithm type was shorter than others, and the total quality value of Max-Coverage algorithm and max quality value type were higher than others. Conclusion: The developed combine scheduling program using Max-Coverage algorithm will provide optimal operation and maximum quality in a limited area and time.

• 한국초지조사료학회지
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• 제39권1호
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• pp.45-52
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• 2019

본 시험은 목장 경영형태에 따른 산지초지 조성시 생산성과 사료가치의 변화를 관찰하기 위하여 수행되었다. 시험에 이용된 초지는 강원도 평창군에 위치한 서울대학교 평창캠퍼스의 시험목장내에 2014년 9월 3일에 조사료 생산형(Forage production type, FP; 오차드그라스 18 + 톨페스큐 12 + 티머시 5 + 화이트클로버 5 kg/ha) 초지와 공공 목장형 (Public farm type, PF; 오차드그라스 12 + 톨페스큐 18 + 티머시 5 + 화이트클로버 5 kg/ha) 초지를 각각 0.5ha씩 조성을 하여 매년 4회 수확 또는 방목을 실시하였으며 파종된 목초의 생육특성, 수량 및 사료가치를 조사하였다. 초장은 화본과목초는 1차 수확시 가장 길었으며 두과목초는 2차 수확시에 가장 길었다. 건물함량은 매년 1차 수확시 가장 높았으며 2차 수확시 유의적으로 낮았다 (p<0.05). 그러나 2년차에서는 2차, 3차 및 4차 수확에 따른 차이는 없었다 (p>0.05). 식생변화에 있어서는 조성이후 시간이 경과함에 따라 두과목초의 비율이 점차 증가되는 경향을 보였으며 2차 및 3차 수확시 잡초와 나지의 비율이 높았지만 4차 수확시는 줄어들었다. 생초 수량은 1년차 전 수확시기에서 목장 형태별 유의성이 있었으나 2년차에서는 유의적인 차이가 없었다. 건물 수량도 생초수량과 같은 경향을 보였으며 전체적으로는 조사료 생산형 초지의 수량이 유의적으로 높게 나타났다 (p<0.05). 공공목장형 초지의 가축 섭취량은 1년차에서는 1,452 kg/ha 이었으나 2년차에는 1,743 kg/ha로 더 높았으며 방목이용율은 3차 방목시 가장 높게 나타났다. 경영형태별 초지의 사료가치는 큰 차이가 없었으나 수확시기 간에는 차이가 나타났다. 조단백질 함량은 1차 수확시 가장 낮았으며 TND 함량은 1차 수확시 가장 높았고 RFV 값은 4차 수확시 가장 높았다. 이상의 결과를 종합하여 볼 때 한국형 산지초지 조성을 위해서는 현장 상황에 맞는 초지의 조성이 중요하며 생산성에 있어서는 조사료 생산형 모델이 더 우수한 것으로 나타났으며 도출된 결과들은 향후 공공목장형 초지 이용을 위한 기초 자료로 제공되었으면 한다.

• 대한기계학회논문집B
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• 제25권5호
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• pp.653-659
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• 2001

This paper is concerned with the development of a new method for making and separating ice in-water and saving floated ice by installing an evaporation panel in an ice storage tank. The new method shows very good heat transfer efficiency than that of the convectional method. It is because the evaporation panel is directly contacted with water in the storage tank. The experiments were performed by varying inlet and outlet refrigerant temperatures of its evaporator. From the experimental results, the operating characteristics of in-water harvest-type ice storage system were investigated by measuring temperature and pressure at each point of the ice storage system and power required to operating compressor respect to the changes of the inlet and outlet refrigerant temperature of evaporator. It can be think that defrost frequency decreased and heavy ice created as the refrigerant temperature of evaporator outlet and defrost setting temperature is low so gotten result can effect to release efficiency. Also, consumption power, condensing heat quantity, refrigerating capacity and performance efficiency decreased as time goes by. Therefore, these results provide the basic data for system optimization, performance improvement and the possibility of application to other fields.

• 한국연초학회지
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• 제7권1호
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• pp.39-47
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• 1985

Normally cultured aromatic tobaccos, KA 101 and KA 103, were primed progressively in three-leaf segments, either 7 days before bud, bud, or early flower stage with 7 days interval, respectively, The cured leaves were weighed for yield, graded, analyzed for quality-related constituents including volatile aroma components. Also the cured leaves were manufactured and smoked by panelists. Yield and quality by price decreased with advancing ripeness. Reducing sugar, total nitrogen, protein nitrogen decreased with successive ripeness, but reverse in this trends with nicotine, petroleum ether extracts and volatile acids components. Among volatile neutral components, furfural, furfuryl alcohol, benzyl alcohol, penethyl alcohol and p-cresol decreased, but solanone increased with delayed harvest. Neophytadiene, oxysolanone, furfuryl aceton was highest at mid harvest, which was judged to be best by panelists. Mid harvest, first primed at bud stage when leaf color comes to pale green to yellow green, seems to be highly recommendable.

• 한국유기농업학회지
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• 제17권1호
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• pp.35-53
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• 2009

The theme-type self-harvest concept proposed in this research will be applied as a relevant reference in planning and realizing urban-rural exchange facilities at the village level. The aim of this paper is to describe the concept, to characterize the self-harvesters and organic farmers involved, to illustrate the ecological, economic and social interaction and the possible constraints of the concept. What is more important, however, is to develop programs for consultants, organic farmers and green-minded consumers, to vitalize direct transaction. The proponents of self-harvest are convinced that this concept leads to ecological, economic and social benefits, which will help to design a sustainable food supply system for small, medium and large cities.

• 한국작물학회지
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• 제63권1호
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• pp.48-56
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• 2018

우리나라에서 수집한 들깨와 차조기의 재배형 및 잡초형 계통들에 대하여 수확 이후 저장기간에 따른 종자발아율 변이를 이해하기 위하여 2016년 가을에 수확한 59개의 들깨, 차조기의 재배형 및 잡초형 계통(재배형 들깨 Type I 15계통, 재배형 들깨 Type II 4계통, 잡초형 들깨 20계통, 잡초형 차조기 20계통)들에 대하여 발아율 및 발아세 조사를 하였다. 수확 후 6개월 동안의 들깨와 차조기의 재배형 및 잡초형 계통들에 대한 발아율 조사에서 재배형 들깨(Type I)의 계통들은 평균 80.8%의 발아율을 보였으나, 들깨와 차조기의 잡초형들은 평균 0.9%와 8.7%의 발아율을 보였다. 또한 재배형 들깨(Type II)의 계통들도 평균 18.2%의 발아율을 보였다. 그리고 발아세의 경우도 재배형 들깨(Type I)의 계통들은 평균 75.8%를 보였으나, 들깨와 차조기의 잡초형들은 평균 0.6%와 6.9%를 보였으며, 재배형 들깨(Type II)의 계통들도 평균 14.3%를 보였다. 그 결과 들깨, 차조기의 재배형 및 잡초형 계통들은 수확 후 1개월째보다 2개월째에서 발아율 및 발아세가 다소 증가한 것으로 보였으나, 그 이후부터 6개월째까지는 크게 증가하지 않는 것으로 보였다. 이상의 결과에 의하면, 재배형 들깨의 경우는 2가지 Type, 즉 발아율이 높은 Type I과 낮은 Type II가 존재하는 것으로 밝혀졌으며, 차조기의 재배형 및 잡초형 계통들은 모두 발아율이 낮은 것으로 밝혀졌다. 본 연구결과는 오늘날 우리나라에서 재배되고 있는 들깨와 차조기 작물의 재배형 및 잡초형 계통들에 대하여 수확 후 6개월까지 저장기간에 따른 종자발아 변이를 이해하는데 기초정보를 제공할 것으로 생각된다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2013년도 임시총회 및 하계학술연구발표회
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• pp.18-18
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• 2013

A FeRh alloy is a well-known efficient magnetocaloric material and some experimental and theoretical studies of bulk FeRh have been reported already by several groups. In this study we report first-principles calculations on magnetic properties of different thickness FeRh thin films in order to investigate the possibility to enhance further the magnetocaloric efficiency. We used Vienna Ab-initio Simulation Package (VASP) code. We found that the FeRh thin films have quite different magnetic properties from the bulk when the thickness is thinner than 6-atomic-layers. While bulk FeRh has a G-type antiferromagnetic (AFM) state, thin films which are thinner than 6-atomic-layers have an A-type AFM state or a ferromagnetic(FM) state. We will discuss possibility of magnetic phase transitions of the FeRh thin films in the view point of a magnetocaloric effect. And we found 4-, 5-, 6-layers films with Fe surface and 7-layers film with Rh surface are FM and they have dozens eV magnetocrystalline anisotropy (MCA) energy. MCA energy leads to determine energy barrier when magnetic states are changed by external magnetic field.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.253-257
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• 2022

The free fibula flap (FFF) is based on the peroneal artery (PA) system, and it is well known that several anatomical variations of the lower limb vascular system exist, including peronea arteria magna (PAM). PAM is a rare congenital variation in which both anterior tibial artery and posterior tibial artery are either aplastic or hypoplastic, and as a result, PA will be the dominant blood supply to the foot. This variation was described as type III-C in Kim-Lippert's Classification of the Infra-Popliteal Arterial Branching Variations. The awareness of its existence is crucial as it often precludes FFF from being harvested due to the risk of significant limb ischemia and limb loss. Despite some literature reporting donor site complications and impending limb loss following FFF harvest in PAM, preoperative vascular mapping before FFF transfer remains controversial among the microsurgeons. We present a case with an incidental intraoperative finding of PAM that had a successful FFF harvest by luck, without preoperative vascular mapping.