• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.2
• /
• pp.238-246
• /
• 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.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.4 no.1
• /
• pp.264-273
• /
• 2001

The conjugate heat transfer from a protruding module in a horizontal channel with a variation of air temperature is experimentally investigated. It is an aim of this study is to estimate temperature difference between a module and air. This study is performed with a variation of parameters that are air temperatures($T_i,=25^{\circ}C{\sim}55^{\circ}C),$ thermal resistance($R_c=158 K/W),$ air velocities ( 4V_i=0.1$ m/s~l.5 m/s ), and input power (Q=3 W, 7 W ). The results show that as the thermal resistance increases, the effect of air temperatures are decreased. And input power was most effective parameter on the temperature difference between a module and air.

• Journal of the Korean Mathematical Society
• /
• v.46 no.1
• /
• pp.99-111
• /
• 2009

A ring is called left P-coherent if every principal left ideal is finitely presented. Let M be a right R-module with the endomorphism ring S. We mainly study the P-coherence of S. It is shown that S is a left P-coherent ring if and only if the left annihilator $ann_S$(X) is a finitely generated left ideal of S for any M-cyclic submodule X of M if and only if every cyclically M-presented right R-module has an M-torsionfree preenvelope. As applications, we investigate when the endomorphism ring S is left PP or von Neumann regular.

• Kyungpook Mathematical Journal
• /
• v.60 no.1
• /
• pp.45-51
• /
• 2020

A module M is called FI-extending if every fully invariant submodule of M is essential in a direct summand of M. In this work, we define a module M to be generalized FI-extending (GFI-extending) if for any fully invariant submodule N of M, there exists a direct summand D of M such that N ≤ D and that D/N is singular. The classes of FI-extending modules and singular modules are properly contained in the class of GFI-extending modules. We first develop basic properties of this newly defined class of modules in the general module setting. Then, the GFI-extending property is shown to carry over to matrix rings. Finally, we show that the class of GFI-extending modules is closed under direct sums but not under direct summands. However, it is proved that direct summands are GFI-extending under certain restrictions.

• Communications of the Korean Mathematical Society
• /
• v.9 no.4
• /
• pp.797-801
• /
• 1994

In [3] Goldman introduced the notion of modules of quotients of a ring with respect to an idempotents kernel functor, which is a generalization of the localization of a module with respect to a multiplicative subset of a communtative ring. For an idempotent kernel functor $\sigma$ on the category of R-modules and for an R-module M, let $Q_\sigma(M)$ denote the module of quotients with respect to $\sigma$.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.6
• /
• pp.73-80
• /
• 2010

This study was conducted to estimate the relative performance of modules with changed characteristics due to long term exposure to the outdoor environment, with a specially made test device for simultaneous measurement of real time power output from the photovoltaic array, taking into account the inclined panel, direct irradiation, power being generated, temperature as well as the optimal analysis timing. In terminology description, M is an abbreviation of module and Group A, Group B are 10 modules series connection (1~10 of M), (11~20 of M) for each of them respectively. The overall mean voltage difference of M-18 with the lowest power output and M-14 with the highest output is-2.13V and it was identifiable that voltage difference was more concentrated to Group B. In addition, in case of M-2 and M-7, M-8, when compared with M-14, the overall mean voltage difference was -0.92V, -1.56 and -0.91V respectively showing the more concentration to Group A. When the temperature of module went up by $1^{\circ}C$, the mean voltage was reduced by 0.35V. For current, Group A was lower than Group B by-0.022A and the ratio of each group was 49.68% and 50.32% respectively, presumably the module with deteriorated properties were more concentrated to Group A relatively. From the comparison of relations with the comprehensive accumulation, M-2, M-7, M-8, M-16 and M-18 were those with deterioration of performance to the worst, thereby requiring precision examination. In comparative efficiency, M-14 was the most excellent one as 12.19% while M-18 as 10.53% was identified that its efficiency was comparatively rapidly reduced.

• Kyungpook Mathematical Journal
• /
• v.58 no.1
• /
• pp.9-17
• /
• 2018

Let $R ={\oplus}_{n{\in}Z}R_n$ be a graded commutative Noetherian ring and let I be a graded ideal of R and J be an arbitrary ideal. It is shown that the i-th generalized local cohomology module of graded module M with respect to the (I, J), is graded. Also, the asymptotic behaviour of the homogeneous components of $H^i_{I,J}(M)$ is investigated for some i's with a specified property.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.2 no.4
• /
• pp.263-269
• /
• 2004

During the last two years, Site Information and Total Environmental database management System (SITES) ver. 1.0 has been developed for the systematic SITES Database Module (SDM), which includes site information, facility information and environmental information. The SITES includes the module for site environmental monitoring system and safety assessment (M&A) system for the nuclear facility. SITES is expected to be an effective system for the radioactive waste disposal management facility. Currently, SITES ver.2.0 is under development after the SITES ver.1.0 that is focused on the M&A system. The main purpose of this paper is to introduce and try to account for the major development in the concept of SEMS sub-module of the M&A module. The SEMS is purposed of development of the program for real time environmental monitoring, prediction, and automatic alarm system using SITES Database and related information.

• Current Photovoltaic Research
• /
• v.10 no.2
• /
• pp.56-61
• /
• 2022

Recently, the expansion of the domestic solar market due to the promotion of eco-friendly and alternative energy-related policies is promising, and it is expected to lead the high-efficiency/high-power module market based on M10 or larger cells to reduce LCOE, 540-560W, M12 based on M10 cells Compared to the existing technology with an output of 650-700W based on cells, it is necessary to secure competitiveness through the development of modules with 600W based on M10 cells and 750W based on M12 cells. For the development of high efficiency/high-power n-type bifacial, it is necessary to secure a lightweight technology and structure due to the increase in weight of the glass to glass module according to the large area of the module. Since the mechanical strength characteristics according to the large area and high weight of the module are very important, design values such as a frame of a new structure that can withstand the mechanical load of the Mechanical Load Test and the location of the mounting hole are required. In this study, a structural analysis design model was introduced to secure mechanical reliability according to the enlargement of the module area, and the design model was verified through the mechanical load test of the actual product. It can be used as a design model to secure the mechanical reliability required for PV modules by variables such as module area, frame shape, and the location and quantity of mounting holes of the structural analysis model verified. A relationship of output drop can be obtained.

• Bulletin of the Korean Mathematical Society
• /
• v.52 no.2
• /
• pp.541-548
• /
• 2015

Let R be a commutative ring. An R-module M is called a w-Noetherian module if every submodule of M is of w-finite type. R is called a w-Noetherian ring if R as an R-module is a w-Noetherian module. In this paper, we present an exact version of the Eakin-Nagata Theorem on w-Noetherian rings. To do this, we prove the Formanek Theorem for w-Noetherian rings. Further, we point out by an example that the condition (${\dag}$) in the Chung-Ha-Kim version of the Eakin-Nagata Theorem on SM domains is essential.