• Nuclear Engineering and Technology
• /
• 제52권5호
• /
• pp.869-877
• /
• 2020

A 24-month Advanced Power Reactor 1400 (APR1400) core with a very-low-boron (VLB) concentration has been investigated for an inherently safe and high-performance PWR in this work. To develop a high-performance APR1400 which is able to do the passive frequency control operation, VLB feature is essential. In this paper, the centrally-shielded burnable absorber (CSBA) is utilized for an efficient VLB operation in the 24-month cycle APR1400 core. This innovative design of the VLB APR1400 core includes the optimization of burnable absorber and loading pattern as well as axial cutback for a 24-month cycle operation. In addition to CSBA, an Er-doped guide thimble is also introduced for partial management of the excess reactivity and local peaking factor. To improve the neutron economy of the core, two alternative radial reflectors are adopted in this study, which are SS-304 and ZrO₂. The core reactivity and power distributions for a 2-batch equilibrium cycle are analyzed and compared for each reflector design. Numerical results show that a VLB core can be successfully designed with 24-month cycle and the cycle length is improved significantly with the alternative reflectors. The neutronic analyses are performed using the Monte Carlo Serpent code and 3-D diffusion code COREDAX-2 with the ENDF/B-VII.1.

• 한국환경과학회지
• /
• 제16권2호
• /
• pp.233-239
• /
• 2007

In the coastal wetland the mud is consist of fine particles, which means that it is characterized by small gap, and heat transfer is obstructed since moisture is found between the gaps. The relationship between net radiation ($R_N$) and soil heat flux($H_G$) shows a counterclockwise hysteresis cycle, which refer to a time lag behind in the maximal soil heat fluxes. The albedo is independent of seasonal variation of the vegetation canopy which plays very important roles to store and control the heat in the atmospheric surface layer.

• 수산해양기술연구
• /
• 제26권4호
• /
• pp.380-386
• /
• 1990

The high stress, low cycle fatigue test were carried out on HT80 plates with artificial part-through notch. The LBB conditions by the net section stress approach was examined in detail. Finite element methods for the state of deformation were also applied and the results were compared with the results from experiments. From the test results, it was noted that the LBB condition in fatigue test was dependent upon the maximun load change before and after the crack penetration. The LBB criterion By the net section stress approach were slightly dependent on initial crack size. It was shown that the state of deformation can be used to predict whether the component is likely to show LBB condition or they will be broken rapidly.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
• /
• pp.39-43
• /
• 2004

A research shows that a new category of software, Collaborative Product Commerce (CPC), is now emerging, allowing discrete manufacturers to once again distinguish themselves on their products and innovations. CPC permits discrete manufacturers to significantly improve the core processes around the management functions associated with the complete product life cycle that are the basis of their existence. As a way to develop computing tools of CPC to support a design process of product, a web-based design supporting system was constructed in the paper. The system consists of C-Product system and Net Meeting Communication system to improve communications between designers and persons for verification of design. The product data files of C-Product system were designed by Pro/Engineer and converted to 3D Viewer format for being used in the web browser. Also, Net Meeting Communication system and Database were developed using ASP and Microsoft SQL 2000 Server to share diverse files that can be utilized to design on the web in real time.

• Journal of Information Processing Systems
• /
• 제15권6호
• /
• pp.1438-1448
• /
• 2019

We present a new technique, called VED (very effective debugging), for detecting and correcting division by zero errors for all types of .NET application. We use applications written in C# because C# applications are distributed through the internet and its executable format is used extensively. A tool called Immunity Debugger is used to reverse engineer executable code to get binaries of source code. With this technique, we demonstrate integer division by zero errors, the location of the error causing assembly language code, as well as error recovery done according to user preference. This technique can be extended to work for other programming languages in addition to C#. VED can work on different platforms such as Linux. This technique is simple to implement and economical because all the software used here are open source. Our aims are to simplify the maintenance process and to reduce the cost of the software development life cycle.

• 통상정보연구
• /
• 제9권3호
• /
• pp.23-32
• /
• 2007

The purpose of this study is to estimate and analyse the relationship between efficiency of bank industry and macroeconomic variables. We employ Johansen's multivariate cointegration methodology, since the model must be stationary to avoid the spurious results. The empirical results show that our model is stationary as well as mean-reverting. This paper also applies impulse-response functions to get additional information regarding the responses of the bank spread to the shocks economic variables such as long and short term interest rates differential, banking organ liquidity, business cycle index, and foreigner's net equity investment. The results indicate that while the bank spread respond positively to liquidity and equity investment shocks and then decay very quickly.

• 수산해양교육연구
• /
• 제27권6호
• /
• pp.1812-1821
• /
• 2015

In this study, we evaluate the eco-efficiency for recycling processes of Busan Resources Recycling Center for each year from 2010-2012. It analyze the impact of global warming on the power consumption by Life Cycle Assessment. Also calculate the economic value by net profit components those are sales amount and electric charge in accordance with the process operation. On the basis of these results, each of the eco-efficiency Factor analysis and dynamics analysis of 2011 and 2012 as the base year to 2010 are performed. As a result, the impact of global warming in all the recycling processes is increased by increasing power consumption 2010-2012. But net profit is decreased. In addition, the eco-efficiency of all the recycling processes is decreased and analysis result of the eco-efficiency trends is located on the Fully non Eco-efficiency (--) level. Therefore, all the recycling processes are necessary improvement for power consumption reducing and net profit increasing to further the environmental and economically sustainable direction.

• 한국토양비료학회지
• /
• 제45권6호
• /
• pp.1179-1186
• /
• 2012

For better understanding of carbon cycle dynamics of an agro-ecosystem, an accurate assessment of seasonal and daily $CO_2$ flux is essential to understand the relationship between various environmental factors and crop productivity. We developed the automatic sliding canopy chamber (ASCC) system that measured continuous net ecosystem productivity (NEP) over whole growing season under the natural meteorological rhythm. The ASCC was composed of two main parts which were sliding part for measuring NEP, and automatic opening and closing chamber (AOCC) for measuring soil respiration (SR) on the soil surface. The ASCC was developed by using open flow method for measuring soil $CO_2$ efflux. The disturbance of natural meteorological condition was minimized by opening the base frames. In the field test with barley (Hordeum vulgare L.), NEP was calculated at $140mg\;CO_2\;m^{-2}h^{-1}$ on a clear day using continuous data and eliminated the possibility of overestimate about 16% using one hour data during the day time. Unlike other small scale chamber system, installation on cropping-field made it possible to take any modifications which might be caused by natural environmental condition.

• 한국수소및신에너지학회논문집
• /
• 제23권3호
• /
• pp.264-273
• /
• 2012

In this paper, two types of integrated gasification combined cycle (IGCC) plants using either an air separation unit (ASU) or an ion transport membrane (ITM), which provide the oxygen required in the gasification process, were simulated and their thermodynamic performance was compared. Also, the influence of adopting a pre-combustion $CO_2$ capture in the downstream of the gasification process on the performance of the two systems was examined. The system using the ITM exhibits greater net power output than the system using the ASU. However, its net plant efficiency is slightly lower because of the additional fuel consumption required to operate the ITM at an appropriate operating temperature. This efficiency comparison is based on the assumption of a moderately high purity (95%) of the oxygen generated from the ASU. However, if the oxygen purity of the ASU is to be comparable to that of the ITM, which is over 99%, the ASU based IGCC system would exhibit a lower net efficiency than the ITM based system.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권1호
• /
• pp.8-14
• /
• 2014

본 연구에서는 R-245fa를 작동유체로 하는 250kW급의 선박폐열회수 발전 시스템을 설계하고 과열기의 구성에 따른 사이클 특성을 연구 하였다. 과열기와 증발기의 직렬연결과 병렬연결의 2가지 조건을 시뮬레이션 하였다. 과열기와 증발기의 직렬연결 시뮬레이션에서는 작동유체 과열에 따른 엔탈피 증가로 4.7%의 출력상승을 얻을 수 있었고, 목표출력을 250kW로 정하였을 경우에는 사이클유량을 4.1% 감소시킬 수 있었다. 과열기와 증발기의 병렬연결 시뮬레이션에서는 사이클의 목표출력을 250kW로 정하였을 경우에 과열기로 가는 열원유체의 유량이 증가함에 따라 사이클 유량이 감소하여 작동유체펌프의 소요동력이 최대 7.9% 감소 하였으며, 유량비율에 따른 사이클효율과 정미효율은 큰 변화가 없었다.