• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.11
• /
• pp.1602-1607
• /
• 2014

This paper deals with the design and property analysis of 7kW-class small-scaled superconducting Linear Synchronous Motor (LSM) and testing equipment for a number of performance pre-tests prior to the development of coreless-type superconducting LSM suitable for 600km/h very high speed train. First, the basic design and property analysis are conducted before developing a small-scaled superconducting LSM model with 2-pole superconducting electromagnets, and additionally the cost-down design of the superconducting electromagnets is conducted to use less high-Tc superconducting wire. Finally, the superconducting magnet coil span is selected at 120mm, and input ground armature current of 670Aturns is required to produce 44.7N of thrust based on research findings.

• Korean Journal of Materials Research
• /
• v.22 no.9
• /
• pp.470-475
• /
• 2012

$La_{1-x}Sr_xMnO_3$(LSM,$0{\leq}x{\leq}0.5$) powders as the air electrode for solid oxide fuel cell were synthesized by a glycine-nitrate combustion process. The powders were then examined by X-ray diffraction(XRD) and scanning electron microscopy (SEM). The as-formed powders were composed of very fine ash particles linked together in chains. X-ray maps of the LSM powders milled for 1.5 h showed that the metallic elements are homogeneously distributed inside each grain and in the different grains. The powder XRD patterns of the LSM with x < 0.3 showed a rhombohedral phase; the phase changes to the cubic phase at higher compositions($x{\geq}0.3$) calcined in air at $1200^{\circ}C$ for 4 h. Also, the SEM micrographs showed that the average grain size decreases as Sr content increases. Composite air electrodes made of 50/50 vol% of the resulting LSM powders and yttria stabilized zirconia(YSZ) powders were prepared by colloidal deposition technique. The electrodes were studied by ac impedance spectroscopy in order to improve the performance of a solid oxide fuel cell(SOFC). Reproducible impedance spectra were confirmed using the improved cell, which consisted of LSM-YSZ/YSZ. The composite electrode of LSM and YSZ was found to yield a lower cathodic resistivity than that of the non-composite one. Also, the addition of YSZ to the $La_{1-x}Sr_xMnO_3$ ($0.1{\leq}x{\leq}0.2$) electrode led to a pronounced, large decrease in the cathodic resistivity of the LSM-YSZ composite electrodes.

• Korean Chemical Engineering Research
• /
• v.43 no.5
• /
• pp.627-631
• /
• 2005

The $(La_{0.8}Sr_{0.2})_{0.95}MnO_3$/yttria-stabilized zirconia (LSM/YSZ) composites were investigated as anode materials for high temperature steam electrolysis using X-ray diffractometry, scanning electron microscopy, galvanodynamic and galvanostatic polarization method. For this purpose, the LSMperovskites were fabricated in powders by co-precipitation method and then were mixed with 8 mol% YSZ powders in different molar ratios. The LSM/YSZ composites were deposited on 8 mol% YSZ electrolyte disks by means of a screen printing method, followed by sintering at temperatures above $1,100^{\circ}C$. From the experimental results, it is concluded that the electrochemical properties of LSM and the LSM/YSZ composites are closely related to their microstructure and operating temperatures.

• Journal of the Korean Ceramic Society
• /
• v.45 no.12
• /
• pp.777-781
• /
• 2008

Experiments were conducted using SUS430 and Crofer 22 APU steels coated by LSM using plasma spray and slurry spray methods, respectively. High-temperature conductivity and oxidation resistance were investigated. For comparison, SUS430 and Crofer 22 APU without LSM coating were also investigated and coefficient of thermal expansion (CTE) was measured. The results show that the materials without LSM coating exhibit almost the same CTE as YSZ electrolyte in a range of temperatures of $550{\sim}850^{\circ}C$. When coated with LSM, the oxidation rate of the steels decreases by $30{\sim}40%$ using slurry spray and by $10{\sim}30%$ using plasma spray whereas the steels using plasma spray have a better high-temperature conductivity than the steels using slurry spray. It is thus concluded that the LSM coating has a limited effect on increasing high-temperature conductivity while it can effectively reduce the oxidation of the steels.

• Journal of Magnetics
• /
• v.14 no.1
• /
• pp.47-51
• /
• 2009

The coreless linear synchronous motor (coreless LSM) has been widely used as a driving source of semiconductor production processes for machine speeding up, positioning accuracy and simple maintenance. However, this coreless LSM suffers the disadvantage of decreased thrust force created by the leakage of magnetic flux. With the goal of increasing the generated thrust force and decreasing the cogging force, the slot of the core part was removed and a moving-coil-type slotless LSM (moving-coil-type slotless LSM) is proposed in this paper. Although this moving-coil-type slotless LSM with a back-yoke at the primary side demonstrated an increase in the generated thrust force, it remained capable of generating the cogging force when the primary side was moved due to the position between the permanent magnet and the back-yoke. Therefore, we attempted to decrease the cogging force of the moving-coil-type slotless LSM. We found that the back-yoke length at the primary side needs to be made $0.5{\tau}$ longer than the integral multiple of the magnetic pole pitch in order to decrease the cogging force created by the moving-coil-type slotless LSM.

• Food Science and Preservation
• /
• v.15 no.6
• /
• pp.903-908
• /
• 2008

This study investigated protein changes in soymilk and whole soymilk due to enzymatic hydrolysis. The total free amino acid contents of low molecular weight soymilk (LSM) and low molecular weight whole soymilk (LWSM) were higher than soymilk (SM) and whole soymilk (WSM). The essential amino acid content was similar in SM and LSM, but was higher in LWSM than WSM. In SDS-PAGE performed to tendency of becoming low molecules, the soy protein molecular weights were 3372 kDa for SM and WSM, but 17 kDa or less for LSM and LWSM. Also, high molecular weight protein spots were evident in 2-D electrophoresis of SM and LSM, but only low molecular weight protein spots of various sizes were evident in WSM and LWSM. This suggests that the high molecular weight protein in SM and WSM is changed to low molecular weight protein by enzymatic hydrolysis. Further investigations of the separation and qualities of these proteins are required.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.32 no.4
• /
• pp.369-378
• /
• 2012

This study was performed out to investigate the influence of the mixed application of chemical fertilizer (CF) and liquid swine manure (LSM) on the growth characteristics, dry matter yield, amino acids, minerals, and free sugars in cultivating silage corn on paddy soils. The field experiment was designed in a randomized block design of 3 repetitions with CF 100% treatment (C), CF 70% + LSM 30% treatment (T1), CF 50% + LSM 50% treatment (T2), CF 30% + LSM 70% treatment (T3), and LSM 100% treatment (T4). At this time, the application of LSM was based solely on the nitrogen. Ear length, ear circle, stem diameter, and stem hardness of the silage corn did not show significant differences between treatments. Fresh yield, dry matter yield and TDN yield were highest in T3, whereas the lowest in C treatment (p<0.05). Crude protein, crude fat, and crude ash content were significantly higher in T1, C, and T4 treatment, respectively (p<0.05). However, NDF, ADF and crude fiber content did not show significant difference between treatments. The total mineral content decreased significantly (p<0.05) as the LSM application rate increased. Total composition amino acid content was higher in the order of T1 > T2 > C > T4 > T3 treatment (p<0.05). Free sugar content was higher in the order of T1 > T3 > T4 > T2 > C treatment (p<0.05). Based on the above results, suggests that the mixed application of chemical fertilizer 30~50% and LSM 50~70% (T2 and T3) is the most effective, considering the yield performance and the content of sugar degree and free sugar affecting silage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.12
• /
• pp.866-870
• /
• 2014

In solid oxide fuel cell system, yttria-stabilized zirconia is generally adopted as the electrolyte, which has high strength and superior oxygen ion conductivity, and the air electrode and the fuel electrode are attached to this. Recently, new structure of 'layered planar SOFC module' was suggested to solve the reliability problem due to the high temperature stability of a sealing agent and a binding material. In this study to materialize the air electrode in a layered planar SOFC module, the LSM ink was coated to form homogeneous electrode in the channel after the ink preparation. As the porosity control agent, PMMA or active carbon powder was adopted with use of a commercial dispersant in ethanol. The optimal amounts of both the porosity control agents and the dispersant were determined. Four (4) vol% of the dispersant for the LSM-PMMA case and 15 vol% for LSM-carbon powder showed the lowest viscosities respectively to indicate the best dispersed states of the slurries. With PMMA and carbon powder, sintered LSM ink shows the relatively homogeneous distributions of pores and with increases of the agents, the porosities increased in both cases. From this, it can be thought that the amount of the PMMA or carbon powder could be used to control the porosity of the LSM ink.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.345-345
• /
• 2023

기후변화에 대응하기 위한 가뭄과 홍수 등의 수재해 관리체계 수립의 필요성이 높아지고 있어, 기후예측모형과 연계하여 수문 및 에너지 순환과정에서 하천유출에 대한 기후변화 영향예측이 가능한 지표수문모형(Land Surface Model, LSM)의 개발과 적용이 요구되고 있다. 또한, LSM은 연속적이고 장기적인 유출을 모의할 수 있어 수재해에 관한 예측과 정보 제공에 유용하므로, 최근 수재해 예측시스템 구축을 위한 주요한 도구로 관심을 받고 있다. 이에 따라, 본 연구에서는 기후모형 CWRF(Climate-Weather Research and Forecasting Model)와 연계되어 물-에너지 순환모의가 가능한 최신 LSM 중 하나인 Common Land Model(CoLM)을 우리나라 유역의 장기하천유출모의에 적용하고자 한다. 대부분의 LSM은 지상의 물과 에너지 순환과정이 각 단일 격자의 수직적인 모의과정으로 제한되고 있었지만, 현재 지속적인 개선을 통해 많은 LSM에서 보다 현실적인 물과 에너지 변화를 모의하고자 노력하고 있다. 그러나, 지속적인 모형의 개선에도 불구하고(또는 그로 인해) 정교한 수학적 프로세스를 통합하여 개선된 최신 LSM은 오히려 복잡한 매개변수 체계, 매개변수 추정, 입력자료, 초기 및 경계조건 등에서 비롯된 불확실성이 존재하고 있다. 따라서, 모형의 주요 매개변수값의 추정은 모의결과의 성능과 안정성을 확보하기 위한 LSM의 모의에서 필수적인 과정 중 하나이다. 유역의 특성에 따라 결정되는 모형 매개변수는 관련자료의 부재 또는 관측의 부정확성으로 인해 검보정 과정을 통해 결정되어야 하므로, 유역의 수문특성을 최대한 반영하고 모형의 성능과 안정성을 확보하기 위해 모의목적에 따라 적절한 검보정 목적함수의 선정도 요구된다. CoLM과 같이 다양한 매개변수가 사용되는 LSM에서는 모의결과에 대한 불확실성을 줄이고, 모의목적에 따른 모형의 예측도 향상을 위해서 모의결과에 민감한 주요 매개변수의 검보정이 과정이 중요하다. 따라서, 본 연구에서는 격자기반 지표수문모형인 CoLM을 이용하여 우리나라 유역의 장기하천유출을 모의하는 과정에서 CoLM의 주요 매개변수 검보정에 필요한 적절한 목적함수의 적용을 통해 CoLM 장기하천유출 모의결과의 예측성능을 개선하고자 한다.

• Proceedings of the KAIS Fall Conference
• /
• 2011.12b
• /
• pp.562-564
• /
• 2011

본 논문에서는 리눅스 운영체제를 기반으로 오픈 소스 침입탐지 시스템인 Snort 등울 LSM(Linux Security Module) 구조의 hooking 부분에 구현시켜 보안 관리자가 의도하는 포트 스캔, DDOS 공격, ARP/IP 위장, 서명 탐지 등이 가능하도록 시스템을 구현하는 방법을 제시하고자 한다.