• Korean Journal of Mathematics
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• 제28권4호
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• pp.907-913
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• 2020

Let R be a commutative ring with identity and let M be a w-module over R. Denote by ℱM the set of all w-submodules of M such that (M/N)w is w-cofinitely generated. Then it is shown that M is w-Artinian if and only if ℱM is closed under arbitrary intersections, if and only if ℱM satisfies the descending chain condition.

• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.113-119
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• 2012

This study aims to examine the effect of the combined application of green roof and PV system on the PV efficiency by measuring the temperature and performance of PV module in order to reduce the temperature on the roof using roof planting system and determine the potential of efficient increase in solar-light power generation. In the experimental methodology, either monocrystalline or polycrystalline PV module was installed in green roof or non-green roof, and then the surface temperature of PV was measured by TR-71U thermometer and again the performance, module body temperature, and conversion efficiency were measured by MP-160, TC selector MI-540, and PV selector MI-520, respectively. As a result, the average body temperature of monocrystalline module was lower by $6.5^{\circ}C$ in green roof than in non-green roof; that of polycrystalline module was lower by $8.8^{\circ}C$ in green roof than in non-green roof. In the difference of generation, the electricity generation of monocrystalline module in green roof was 46.13W, but that of polycrystalline module was 68.82 W, which indicated that the latter produced 22.69W more than the former.

• 한국전자통신학회논문지
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• 제9권11호
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• pp.1311-1316
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• 2014

본 논문의 X-대역 25W 전력증폭기 모듈은 위성통신용 지상단말기의 송신기에 사용되는 것으로, 정지궤도 36,000Km 통신위성에 송신하기 위한 송출장비인 고출력증폭기를 구성하는 일부분이다. 지상단말에서 사용하는 고출력증폭기는 총 4개의 전력증폭기 모듈이 연계구조형으로 구성되어 고출력의 특성을 갖는다. 연계구조형에 사용된 전력증폭기 모듈 4개중에 각 모듈은 순차구조형(Serial Combining Structure)으로 구성된다. 이 전력증폭기 모듈은 Hybrid 기법을 이용하여 10개의 MMIC 전력 증폭기 칩과 Al2O3 박막 기판으로 제작한 회로를 결합하여 PAM(Power Amplifier Module)을 구성함으로써 X-대역 운용주파수에서 출력전력 25W의 전력증폭기 모듈을 구현하였다.

• 대한수학회보
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• 제59권1호
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• pp.213-226
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• 2022

Let R be a ring and M an R-module. Then M is said to be regular w-flat provided that the natural homomorphism I ⊗_R M → R ⊗_R M is a w-monomorphism for any regular ideal I. We distinguish regular w-flat modules from regular flat modules and w-flat modules by idealization constructions. Then we give some characterizations of total quotient rings and Prüfer v-multiplication rings (PvMRs for short) utilizing the homological properties of regular w-flat modules.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.39-45
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• 2007

In this paper, we analyzed the elements of measurement uncertainty on electrical performance test which are the most important things in photovoltaic module performance test. Repeating the performance test by 6 men, the measurement uncertainty could be calculated. In this experiment, Solar Simulator (A-Class pulse type) used for domestic certificate test of PV module is Pasan IIIb (Balval, Switzerland). The possible elements of the measurement uncertain that could effect electrical performance test of PV module are reference cell, spectrum correction, error from measurement repetition, test condition, stability and uniformity of artificial solar simulator. To find the measurement uncertainty, 6 men repeated the test by 10 times. And the results were that numerical average value was 124.44W and measurement uncertainty was $124.44W{\pm}0.36W$ with 95% confidence level for 125W PV module(KD-5125).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.5-7
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• 2006

In this paper, we analyzed the elements of measurement uncertainty on electrical performance test which are the most important things in photovoltaic module performance test. Repeating the performance test by 6 men, the measurement uncertainty could be calculated. In this experiment, Solar Simulator (A-Class pulse type) used for domestic certificate test of PV module is Pasan IIIb (Balval, Switzerland). The possible elements of the measurement uncertain that could effect electrical performance test of PV module are reference cell, spectrum correction, error from measurement repetition, test condition, stability and uniformity of artificial solar simulator. To find the measurement uncertainty, 6 men repeated the test by 10 times. And the results were that numerical average value was 124.44W and measurement uncertainty was $124.44W{\pm}0.75W$ with 95% confidence level for 125W PV module.

• 설비공학논문집
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• 제13권5호
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• pp.348-355
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• 2001

The coupled conduction and convection heat transfer from a protruding heated module in a horizontal channel with a variation of channel height is experimentally investigated. The input power to the module is 3, 7W and thermal resistance of module support is 0.06 , 1.03 and 158K/W. the Reynolds number ranged from 350 to 4500 corresponding to the inlet velocity(0.4~1.3 m/s) and channel height(11~35 mm). The results were obtained that the decrease of thermal resistance of module support reduces the module temperature by redistributing the heat flux and the overall thermal resistance of the module. In the study the effect of channel height is very significant in the adiabatic condition, but negligible in the conjugate condition. Finally, correlations for Nusselt number and $Q_B$/Q with a variation of Reynolds number were developed respectively.

• 대한기계학회논문집B
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• 제28권2호
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• pp.238-246
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• 2004

This paper reports an experimental study around a module about forced air flow by blower (35${\times}$35${\times}$6㎣) in a portable personal computer model(200${\times}$235${\times}$10㎣). Experimental report is to know three data to investigate thermal resistance, adiabatic wall temperature and visualized fluid flow around the module by combination of the moving number and the arrangement method of blower. The channel inlet flow velocity has been varied between 0.26, 0.52 and 0.78㎧, and input power ( $Q_{p}$) to the module is 4W. To investigate thermal resistance. the heated module is mounted on two boards(110${\times}$110${\times}$1.2㎣, k=20.73, 0.494W/ $m^{\circ}C$) in parallel-plate channel to forced air flow. The temperature distribution were visualized by heated module on acrylic board(k=0.262W/ $m^{\circ}C$) using liquid crystal film. Fluid flow around the module were visualized using particle image velocimetry system.

• 설비공학논문집
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• 제26권5호
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• pp.224-230
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• 2014

The purpose of this paper is to investigate the performance of supplemental cooling and heating system equipped with the 1 kW thermoelectric module. The system consist of 96 thermoelectric modules, heat sink with louver fin and water cooling jacket which is attached on the hot side of the thermoelectric module. The cooling and heating performance test of the thermoelectric system is conducted with various conditions, such as intake voltage, air inlet temperature, air flow volume, water inlet temperature and water flow rate at calorimeter chamber in consideration of environmental conditions in realistic vehicle drive. The experimental results of a thermoelectric system shows that the cooling capacity and COP is 1.03 kW, and 1.0, and heating capacity and COP is 1.53 kW, and 1.5 respectively.

• 대한전자공학회논문지TC
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• 제46권12호
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• pp.14-21
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• 2009

본 논문에서는 7개의 MMIC 전력증폭기 칩과 박막기판을 결합하여 MIC 모듈을 구성함으로써 Ka-대역 중심주파수 영역에서 10 W 이상의 출력전력을 가지는 펄스모드 전력증폭기 모듈을 설계하고 제작하였다. 전력증폭기 모듈의 제작에는 밀리미터파 대역에 적합한 수정된 형태의 윌킨슨 전력분배기/합성기와 모듈의 조림과정에서 공진을 억제하고 작은 삽입손실 특성을 보이는 CBFGCPW-Microstrip 천이구조를 활용하였다. 전력용 MMIC 바이어스 회로에 사용된 큰 값의 바이패스 캐패시터에 의해 발생되는 펄스모드 출력전력의 감소를 개선하고자 TTL 펄스 타이밍 제어 기법을 제안하였다. 제안된 방법을 10 kHz, $5\;{\mu}sec$ 펄스모드로 동작하는 전력증폭기 모듈에 적용한 결과 펄스모드 동작시간을 200 nsec 이상 개선할 수 있었고 0.62 W의 출력전력을 향상시킬 수 있었다. 구현된 전력증폭기 모듈은 59.5 dB의 전력이득과 11.89 W의 출력전력을 보여주었다.