• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.580-581
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• 2018

에너지 하베스팅 무선센서네트워크에서 end-to-end delay를 줄이기 위해 멀티홉 라우팅기법을 적용한 매체접근제어 프로토콜 들이 연구되었다. 실제 환경에서는 소비되는 에너지 보다 충분히 많은 에너지 수집이 어려운 상황이 많이 발생하게 된다. 따라서 멀티홉 전송에서 전력이 고갈되지 않고 노드들이 안정적으로 데이터를 릴레이 할 수 있도록 하는 MAC프로토콜의 설계가 요구된다. 본 논문에서는 네트워크 수명을 증가시키기 우해 잔여전력과 에너지 수집율에 따라 릴레이노드를 선택할 수 있는 전력효율적인 MAC프로토콜을 제안하고 시뮬레이션을 통해 그 성능을 비교분석하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권12호
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• pp.1729-1735
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• 2011

The effect of flaxseed meal on broiler performance, carcass characteristics, alpha-linolenic acid contents, and organoleptic characteristics of chicken meat was studied during a 42 day experiment. Broiler chicks were randomly allotted to 4 experimental groups and fed iso-energetic and iso-nitrogenous diets containing flaxseed meal at 0, 5, 10 and 15%. Flaxseed meal did not affect the weekly body weight of broiler chicks during the first two weeks but thereafter weekly body weight reduced among flaxseed meal groups. At the end of $6^{th}$ week, birds fed on 15% flaxseed meal showed a reduction of 8% in body weight compared to the control group. Control group had significantly higher weight gain with slightly higher feed consumption and better feed conversion ratio (FCR), protein efficiency ratio (PER), and energy efficiency ratio (EER) than the flaxseed meal groups. Among the treatments, birds of 5 and 10% flaxseed meal groups had significantly better FCR, PER and EER compared to those of the 15% flaxseed meal group. The carcass characteristics data indicated a significant reduction in the eviscerated weight and breast yield at 15% flaxseed meal in the diet as compared to other dietary groups. However, the alpha-linolenic acid content in both breast and thigh meat was higher with an increasing level of flaxseed meal in the diets without affecting the sensory acceptability of meat. Based on the present study, up to 10% of flaxseed meal may be used in broiler diet to enhance the alpha-linolenic acid content in the broiler meat.

• Journal of Biosystems Engineering
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• 제3권1호
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• pp.33-46
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• 1978

To get the goal of self-supply of food grain, improvement of post-harvest grain operations in rural area is under consideration as an important task of agriculture in Korea. This is study is focused on elimination of losses and deteriorations of grain and reduction of labour requirements and funds for post-harvest grain operations. The purpose of this study are presentation of basic data referring to conventional post-harvest grain operations in rural area and suggestion of improving methods for the operations, and also finding out reasonable operating processes of the operations. The result of this study are follows; 1. Grain drying in-the-filed which is performed before threshing has major factors of grain loss during drying, and so should be restrained as possible. Combine harvesting system is recommended among other king of mechanized harvesting systems for restraining in-the-field drying and securing available labors for drying. 2. It is predicted that mechanical grain drying could be prevalent when combine harvesting is taken place. Recommended grain drier for pre-combine harvesting system and for combine harvesting system is batch-type drier and circulating -type drier, respectively. 3. As existing farm storages for grain have insufficient spaces and offer poor conditions for grain storing , it is greatly needed to build up new storage which store only grains. And it is concluded that storing grain in community common storages in desirable. 4. Power supplying system for milling machinery in local milling plants, that a large capacity prime mover supplies power to 4 to 6 kinds of milling machinery simultaeously, should be converted to a system of several small capacity prime movers supplying power to each machiner y for the purpose of reducing extra consumption of energy. 5. Governmental grain, of which Korean farms produced, should be milled and stored in the local milling plant successively for the purpose of reducing transportation fee and stroing facilities. 6. Furture post-havest grain operations-drying, storing and milling should be periormed successively in he community common plant. And average optimum processing capacity of the plant is estimated about 300 metric ton of grain every year.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.637-647
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• 1993

Over 40 per cent Indian population needs to be attended for nutritional improvement. Traditional nutritious food resources though abundantly available but presently less used, if incorporated in the diets, can yield low-cost nutritionally balanced diets. The linear programming (LP)model was used for optimization of food resources to satisfy protein -energy requirements of hard working rural poor. Soybean-a highly nutritious food legume-available at reasonably low price was included along with chick -pea and pigeon -pea for comparison .The three cereals predominantly used in Indian diets -rice, wheat and sorghum -and three typical leafy vegetables namely, spinach , drumstick leaves and rajagira (Amaranths paniculantus) leaves were used for optimization . The contribution of food legume was restricted to supply only 50 per cent of daily protein requirement for maximum protein value. The quantities of other food stuffs namely , milk , sugar , tubers etc. were restricted to nati nal per capita availability. the nutrition satisfaction levels in per cent RDA by the model are 149-250 for protein , 51-106 for fat, 134-362 for iron an d143-1158 for Vitamin-A. Quantities of food legumes, cereals and leafy vegetables ranged from 289-601, 3000-3700 and 360-1200 g/day respectively for a reference family of five hard working rural poor. Daily food resources cost ranged from US$ 0.6 to 1.0 for the family. Amongst food legumes, soybean based diet combinations provide maximum nutritional benefits at minimum cost indicating its suitability for wider adoption by hard working poor.

• Journal of Radiation Protection and Research
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• 제28권1호
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• pp.9-18
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• 2003

벼를 쌀알의 발육단계별로 주간 및 야간에 1 시간 동안 HTO 증기에 피폭시키고 작물체 부위별로 조직자유수 $^3H$ (TFWT) 및 유기결합형 $^3H$ (OBT) 농도를 조사하였다. 피폭종료 직후$(h_0)$ 잎의 TFWT 농도는 주간실험에서는 공기수분중 1 시간 평균 HTO 농도의 100% 내외였으나 야간실험에서는 $30{\sim}40%$에 불과하였다. 주 야간 피폭 모두 TFWT 농도는 초기에는 급히 감소하다가 나중에는 훨씬 천천히 감소하였고 수확시에는 $h_0$에 비해 수백${\sim}$수만 배 낮았다. OBT 농도는 부위 및 피폭시기에 따라 변화양상이 달랐고 $h_0$와 수확시 간 차이는 대체로 10 배 이내였다. 야간피폭 중에도 주간피폭의 약 1/3 수준으로 OBT가 생성되었다. 공기중 HTO의 수확시 쌀알내 OBT로의 전환 정도는 주간피폭시 야간피폭보다 수 배 높았고 주 야간 피폭 모두 쌀알의 발육 최성기 피폭시에 가장 높았다. 벼가 쌀알의 발육기에 HTO에 피폭되면 OBT에 의한 섭취피폭선량이 TFWT보다 훨씬 클 것으로 추정되었다.

• 전력전자학회논문지
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• 제15권2호
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• pp.150-158
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• 2010

본 논문은 입력단 전압과 출력단 부하전압의 상대적 크기에 따라 동작모드가 다르게 구성되며, 열전에너지 수확이 가능한 새로운 공진형 DC/DC 컨버터의 동작 특성을 해석한다. 공진형 DC/DC 컨버터는, 직류 입력전원에 연결 되는 LC 공진회로와, 공진회로의 캐패시터 전압이 최대일 때 부하측으로 에너지를 전달하는 펄스형 공진 컨버터로 구성되어있다. 입력단 LC 공진회로의 캐패시터는 전압의 최대값이 입력전압의 최대값의 2배가 되는 Voltage Doubler의 특성을 갖는다. 제안한 컨버터는 공진 캐패시터 전압의 최대값과 부하전압의 상대적 크기에 따라서 승압형 연결, 혼합형 연결, 직접연결의 3가지 동작특성을 가진다. 승압형 연결은 공진 캐패시터 전압의 최대값이 부하전압보다 작은 경우이다. 혼합형 연결은 공진 캐패시터 전압의 최대값이 부하전압보다 큰 경우이며, 스위칭 주기에 직접연결과 승압형 연결이 연속하여 나타난다. 직접연결은 입력단 전압의 크기가 부하전압보다 큰 경우이며, 입력단 에너지가 부하측으로 컨버터의 스위칭 동작 없이 직접 전달된다. 공진형 DC/DC 컨버터 회로의 동작원리를 설명하고, PSPICE 시뮬레이션 및 실험을 통하여 검증하였으며, 열전에너지 수확분야에 활용 가능성을 제시하였다.

• 한국전기전자재료학회논문지
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• 제23권8호
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• pp.601-604
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• 2010

In this study, the piezoelectric energy harvester was investigated employing the pillar structure with the diameter size of 50~500 um. Usually, the aspect ratio between the height and diameter was related with the piezoelectric performance. High aspect ratio was showed the low electric noise and high piezoelectric properties than low aspect ratio. Therefore, we have selected the Su-8 photo-resist and modified lithography process to manufacture the pillar structure with height above the 250 ${\mu}m$. In this presentation, we will report the process and properties of micro pillar structure based on the PMN-PZT (Pb$(Mg_{1/3}Nb_{2/3})O_3$-PbZrTiO$_3$) materials.

• 한국위성정보통신학회논문지
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• 제10권4호
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• pp.71-76
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• 2015

본 연구는 LTE, 5G의 무선 통신네트워크망에서 효율적으로 무선에너지하비스팅과 데이터 전송 실시하기 위한 시스템 모델을 제시한다. 수신 된 신호의 파워를 타임 스위칭(Time Switching)과 파워 스플릿팅(Power Splitting) 기법을 통해 우리가 원하는 무선에너지하비스팅 효율과 데이터 전송률을 만족시키기 위한최적의 타암 & 파워 비율을 찾는다. 그래서 최적의 시간 & 파워 비율을 선정함으로써 우리는 효율적으로 데이터 전송과 에너지하비스팅이 가능하다. 또 이상적인 수신기와 제안한 시스템 모델의 비교를 통해 성능 분석을 실시하고, 앞으로의 연구방향을 제시한다.

• 방사선산업학회지
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• 제5권2호
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• pp.101-106
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• 2011

The separation of germanium and gallium ion with metal oxide was introduced into the development of $^{68}Ge/^{68}Ga$ generator. Germanium and gallium within mixed solution were respectively separated by using a liquid-liquid extraction and a column chromatographic method. The separation of Ge within high concentrated hydrochloric and sulfuric acid was conducted by the extraction to $CCl_4$ and the back-extraction to 0.05 M HCl. An optimum condition of the extraction by $CCl_4$ was in 5~7 M HCl and efficiency was around 80%. The gallium was selectively separated by using $Al_2O_3$ among metal oxides as sorbents from the mixed solution in 0.04~0.10 M HCl condition.

• Advances in nano research
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• 제14권1호
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• pp.27-43
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• 2023

This article investigates the energy harvesting characteristics of a magneto-electro-elastic (MEE) cantilever beam reinforced with carbon nanotubes (CNT) under transverse vibration. To this end, the well-known lumped parameter model is used to represent the coupled multiphysics problem mathematically. The proposed system consists of the MEE-CNT layer on top and an inactive substrate layer at the bottom. The substrate is considered to be made of either an isotropic or composite material. Basic laws such as Gauss's Law, Newton's Law and Faraday's Law are used to arrive at the governing equations. Surface electrodes across the beam are used to harvest the electric potential produced, together with a wound coil, for the generated magnetic potential. The influence of various distributions of the CNT and its volume fraction, substrate material, length-to-thickness ratio, and thickness ratio of substrate to MEE layer on the energy harvesting behaviour is thoroughly discussed. Further, the effect of external resistances and changes in substrate material on the response is analysed and reported. The article aims to explore smart material-based energy harvesting systems, focusing on their behaviour when reinforced with carbon nanotubes. The results of this study may lead to an improved understanding of the design and analysis of CNT-based smart structures.