Gas turbine engines are widely used as prime movers of generator and propulsion system in warships. This study addresses the problem of designing a DS-based PID controller for speed control of the LM-2500 gas turbine engine used for propulsion in warships. To this end, we first derive a dynamic model of the LM-2500 using actual sea trail data. Next, the PRC (process reaction curve) method is used to approximate the first-order plus time delay (FOPTD) model, and the DS-based PID controller design technique is proposed according to approximation of the time delay term. The proposed controller conducts set-point tracking simulation using MATLAB (2016b), and evaluates and compares the performance index with the existing control methods. As a result of simulation at each operating point, the proposed controller showed the smallest in , which means that the rpm does not change rapidly. In addition, IAE and IAC were also the smallest, showing the best result in error performance and controller effort.

This study was carried out to investigate the effect of chlorine water and plasma gas treatment on the quality and microbial control of Latuca indica L. baby Leaf during storage. Latuca indica L. baby leaves were harvested from a plant height of 10cm. They were sterilized with 100μL·L-1 chlorine water and plasma-gas (1, 3, and 6hours), and packaged with 1,300cc·m-2·day-1·atm-1 films and then stored at 8±1?and RH 85±5% for 25days. During storage, the fresh weight loss of all treatments were less than 1.0%, and the carbon dioxide and oxygen concentrations in packages were 6-8% and 16-17%, respectively for all treatments in the final storage day. The concentration of ethylene in the packages fluctuated between 1-3μL·L-1 during the storage and the highest concentration of ethylene was observed at 6 hours plasma treatment in the final storage day. The off-odor of all treatments were almost odorless, the treatments of chlorine water and 1 hour plasma maintained the marketable visual quality until the end of storage. Chlorophyll content and Hue angle value measured at the final storage day were similar to those measured before storage in chlorine water and 1 hour of plasma treatments. E. coli was not detected immediately after sterilization in all sterilization treatments. After 6 hours of plasma treatment, the total bacteria fungus counts were lower than the domestic microbial standard for agricultural product in all sterilization treatments. The total aerobic counts in the end storage day increased compared to before storage, whereas E. coli was not detected in all sterilization treatments. The sterilization effect against bacteria and fungi was the best in chlorine water treatment. Plasma treatment showed sterilization effects, but within a prolonged period of time. In addition, the sterilization effect decreased gradually. These results suggest that chlorine water and plasma treatment were effective in maintaining Latuca indica L. baby Leaf commerciality and controlling microorganisms during postharvest storage.

현재까지의 저장시설 내 저장해충 방제는 주로 메칠브르로마이드(MB)나 PH3와 같은 고독성 훈증제를 사용하여 왔으나 이와 같은 화학약품의 사용은 인축에 잔류독성이나 생태계 파괴와 같은 부작용을 초래하였다. 따라서 화학약품 의 사용을 최대로 억제하면서 친환경적이고 효과적인 방제방법이 요구되고 있다. 본 연구는 이산화염소(ClO2) 가스를 이용하여 저장시설 내 대표적 저장해충인 화랑곡나방과 어리쌀바구미의 치사율, 생존율, 부화율, 용화율 및 발육일수 등의 생태적 특성을 조사하여 이산화염소의 저장해충에 대한 효과와 적용 가능성을 검증하고자 하였으며, 연구는 실험실과 야외 운반용 컨테이너 및 실제 저장시설인 미곡처리장에서 진행되었다. 이산화염소 가스를 이용한 저장해충 방제는 기존 훈증제의 사용을 대체할 수 있는 효과적이고 친환경적인 방법으로 저장시설의 규모, 농도, 처리시간, 대상해충 종에 따라 효과적으로 조절이 가능하여 방제효과와 경제성 두 가지 측면을 극대화 할 수 있을 것이라 생각된다.

This study was conducted to develop and evaluate an appropriate control device for a purge type controlled atmosphere (CA) storage in Korea. To determine ideal performance, oxygen and carbon dioxide control capability and airtightness were analyzed according to the postharvest management manual of CA storage of Fuji apples. In shortened experiments for CA storage, the condition was delayed CA at 0-0.5oC for three days and stored at 0.1-0.5% carbon dioxide levels for 3 days and then further stored 6 days under 1% carbon dioxide. As a result, the temperature control range of a developed CA container was 0.0-0.5oC, and the relative humidity was more than 90%, except for the defrosting step for the freezer during the storage period. The rate of pressure reduction for the CA container in the negative and positive pressure states was 0.45 and 0.21 mmH2O/min, respectively, and it was twofolds higher than standard airtightness for CA storage. After nitrogen injection, oxygen concentration was achieved at 2%, and carbon dioxide concentration was maintained at 0.1-0.5% for 6 days. Afterwards, carbon dioxide levels were tightly controlled between 0.1-1.0%. These results suggest that a developed purge type CA container could be effective in commercially maintaining the quality of agricultural products.

In this study, the porous ceramic filter was developed to be able to remove both dust and hazardous gas contained in fuel gas at high temperature. The porous ceramic filters were fabricated and used as a catalyst support. And the effects have been investigated such as the mean particle size, organic content and addition of foaming agent on the porosity, compressive strength and pressure drop of ceramic filters. With the increase of mean powder size and the organic content for the cordierite filter, the porosity was increased, but the compressive strength and pressure drop were decreased. From the results of the research, the optimum condition for the fabrication of ceramic filters could be acquired and they had the porosity of 58%, the compressive strength of 13.4 MPa and the pressure drop of 250 Pa. It was expected that this ceramic filter was able to be applied to the glass melting furnace, combustor, and dust/toxic gas removal filter.

Vacuum kinetic spray(VKS) is a relatively advanced process for fabricating thin/thick and dense ceramic coatings via submicron-sized particle impact at room temperature. However, unfortunately, the particle velocity, which is an important value for investigating the deposition mechanism, has not been clarified yet. Thus, in this research, VKS average particle velocities were derived by numerical analysis method(CFD: computational fluid dynamics) connected with an experimental approach(SCM: slit cell method). When the process gas or powder particles are accelerated by a compressive force generated by gas pressure in kinetic spraying, a tensile force generated by the vacuum in the VKS system accelerates the process gas. As a result, the gas is able to reach supersonic speed even though only 0.6MPa gas pressure is used in VKS. In addition, small size powders can be accelerated up to supersonic velocity by means of the drag-force of the low pressure process gas flow. Furthermore, in this process, the increase of gas flow makes the drag-force stronger and gas distribution more homogenized in the pipe, by which the total particle average velocity becomes higher and the difference between max. and min. particle velocity decreases. Consequently, the control of particle size and gas flow rate are important factors in making the velocity of particles high enough for successful deposition in the VKS system.

For replacement of methyl bromide(MB) in Korea, VapormateTM, a gas formulation of ethyl formate(EF) with carbon dioxide, are firslty introduced in import bananas and VivakilTM, a gas formulation of phosphine(PH3) with carbon dioxide, are ready to commercial use in export cut flowers. Their applications are being extended for other import and export commodities. Ethyl formate have been shown to have effectiveness short exposure time(<4hr) but it has a limited application at low temperature for TSM(Two spotted spider mites) due to some phytotoxic to strawberry. Phosphine gas has demonstrated their efficacy to TSM at low temperature but only meets quarantine requirement when applying longer fumigation time(>24hr) to control CA(cotton aphids). We firstly evaluated two MB alternatives, EF and PH3, have enhansive effect within short exposure time(4hr) at low temperature(5℃) for controlling both TSM and CA without any injury to export strawberries.

In the present work, bismuth nanopowders with various particle size distributions were synthesized by controlling argon (Ar) gas flow rate and chamber pressure of a gas condensation (GC) apparatus. From the analyses of transmission electron microscopy (TEM) images and nitrogen gas adsorption results, it was found that as Ar gas flow rate increased, the specific surface area of bismuth increased and the average particles size decreased. On the other hand, as the chamber pressure increased, the specific surface area of bismuth decreased and the average particles size increased. The optimum gas flow rate and chamber pressure for the maximized electrochemical active surface area were determined to be 8 L/min and 50 torr, respectively. The bismuth nanopowders synthesized at the above condition exhibit 13.47 of specific surface area and 45.6 nm of average particles diameter.

The effects of reaction temperature and precursor concentration on the microstructure and magnetic properties of nanoparticles synthesized as final products of iron acetylacetonate in chemical vapor condensation (CVC) were investigated. Pure phase was obtained at temperature above and crystallite size of nanoparticles decreased with lowering precursor concentration. Also, the coercivity decreases with decreasing crystallite size of nanopowder. The lowest coercivity was 7.8 Oe, which was obtained from the nanopowder sample synthesized at precursor concentration of 0.3M. Then, the crystallite size of nanoparticles was 8.8 nm.

가스터빈 기관은 우주항공, 발전 플랜트뿐만 아니라 해상운송 분야에 사용되는 원동기로서 매우 중요한 역할을 하고 있다. 그러나 그 구조가 복잡하고 연소과정에서 시간지연 요소가 포함되어 있어 가스터빈 기관을 잘 제어할려면 정교한 수학적 모델링이 필요하다. 본 논문 에서는 가스터빈 기관의 주요 구성품인 가스발생기, PLA 액추에이터, 미터링 밸브에 대한 모델링 기법을 설명한다. 또한, 가스터빈 기관의 시 운전 데이터를 기초로 몇 가지 정상상태 때의 동작점에서 서브모델을 구하고, 각 서브모델에 대해 비선형 비례적분미분 제어기를 설계하여 기 관의 속도를 제어하는 방법을 제안한다. 제안하는 비선형 제어기는 비선형 함수로 구현되는 3가지 이득을 사용한다. 비선형 제어기의 파라미터 는 제어시스템의 목적함수를 최소화하는 관점에서 실수코딩 유전자알고리즘으로 동조한다. 제안한 방법은 가스터빈 기관에 적용하고 시뮬레이 션을 실시하여 그 유효성을 확인한다.

식물체에 대한 에틸렌의 다양한 반응에도 불구하고, 감자 가공 산업을 중심으로 에틸렌의 맹아억제제로서의 가능성에 관해서만 주로 검토되어 왔다. 그러나 본 연구에서는 씨감자에 에틸렌을 처 리하여 생리적 서령 조절제로서의 가능성을 확인코자 하였다. 국내 에서 가장 많이 재배되고 있는 ‘수미’ 감자를 대상으로 처리방법, 처리농도 등을 달리하여 저장 중 에틸렌 가스를 처리 한 후 휴면타파 및 맹아의 생장에 미치는 영향을 조사하였다. 에틸렌이 처리된 감자 괴경은 처리 후 1~2일에 급격히 호흡율이 상승해 감자 괴경의 에틸렌에 대한 민감한 반응을 확인할 수 있었다. 3일간의 단기간 에 틸렌 처리는 감자 괴경의 휴면을 약간 타파시키는 결과를 보였으 나, 2 μL/L 농도의 연속 처리구에서는 오히려 저장 40일까지 전혀 맹아가 되지 않아 뚜렷한 맹아억제 효과를 보였다. 에텔린 농도와 처리기간을 달리한 연속처리 시험에서는 2 또는 4μL/L 농도 처리 구 공히 뚜렷한 맹아억제 효과를 다시 확인할 수 있었고, 짧고 많은 수의 맹아가 발생되는 현상을 발견할 수 있었다. 이렇게 에틸렌이 처리된 씨감자를 온실 내 포트에 파종하여 재배한 결과 출현속도에 서는 큰 차이가 없었으나 에틸렌 처리에 의해 식물체당 줄기수와 복지수가 증가되었다. 수량성에서는 뚜렷한 경향 없이 처리 간 약 간의 차이를 보였으나 식물체당 괴경수는 에틸렌 처리에 의해 현저 히 증가되는 결과를 확인할 수 있었다. 이상의 결과를 종합해 볼 때, 저장중 씨감자를 대상으로 한 에틸렌 가스 처리, 특히 2~4μL/L 농 도범위에서 씨감자의 생리적 서령을 조절하는 유용한 수단으로 활 용될 수 있을 것으로 기대된다.