• Asian-Australasian Journal of Animal Sciences
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• 제22권1호
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• pp.107-112
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• 2009

This study was conducted to investigate the effect of feed particle size and feed form on growth performance, nutrient metabolizability and intestinal morphology in broiler chickens. This experiment was a 2${\times}$2 factorial arrangement including two feed particle sizes (fine and coarse) and two feed forms (mash and pellet). A total of two hundred and eighty eight day-old male Arbor Acre broilers were used in this six week experiment. Birds were randomly allotted to four dietary treatments with six replicates per treatment and twelve birds per replicate. The results showed that pelleting diets resulted in greater ADG (p<0.01), greater ADFI (p<0.01) and lower feed to gain ratio (F/G) (p<0.05) during starter, grower and overall period. Also, pelleting improved both apparent metabolizable energy (AME) (p<0.01) and the apparent metabolizability of crude protein (p<0.05) and organic matter (p<0.05) regardless of the phase. Reduction of feed particle size enhanced AME (p<0.05) during d 19 to 21. Increased villus height (p<0.05) and crypt depth ratio (p< 0.05) within duodenum, jejunum, and ileum were observed in birds fed the pellet diet compared with those given the mash diet. In conclusion, results indicated that feed pellets might enhance performance by improving nutrient metabolizability and digestive tract development.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.266-271
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• 2009

The present study numerically investigated the effect of the geometry of the flattened tube on the thermal performance of a high temperature generator (HTG) of a double effect LiBr-water absorption system. The heat transfer tubes of the HTG were arranged behind a metal fiber burner. The heat transfer of the tubes of HTG were consisted with a set of circular and flattened tubes in series. FLUENT, as a commercial code, was applied for estimating the thermal performance of the HTG. Key parameters were the tube arrangement in the HTG. Temperature and velocity profiles in the HTG were calculated to estimate the thermal performance of the HTG. The heat transfer rate of a HTG tube was increased, and the gas temperature around the flattened tube was decreased as the pitch ratio was increased. The heat transfer rate for the circular tube bundle with the pitch ratio of 2.48 were larger by 10% respectively than that of 2.10 and the heat transfer rate for the flattened tube bundle with the pitch ratio of 1.88 were larger by 36% respectively than that of 1.63.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권7호
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• pp.328-334
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• 2002

The DNA chips are devices associating the specific recognition properties of two DNA single strands through hybridization process with the performances of the microtechnology. In the literature, the "Gene chip" or "DNA chip" terminology is employed in a wide way and includes macroarrays and microarrays. Standard definitions are not yet clearly exposed. Generally, the difference between macro and microarray concerns the number of active areas and their size, Macroarrays correspond to devices containing some tens spots of 500$\mu$m or larger in diameter. microarrays concern devices containing thousnads spots of size less than 500$\mu$m. The key technical parameters for evaluating microarray-manufacturing technologies include microarray density and design, biochemical composition and versatility, repreducibility, throughput, quality, cost and ease of prototyping. Here we report, a new method in which minute particles are arranged in a random fashion on a chip pattern using random fluidic self-assembly (RFSA) method by hydrophobic interaction. We intend to improve the stability of the particles at the time of arrangement by establishing a wall on the chip pattern, besides distinction of an individual particle is enabled by giving a tag structure. This study demonstrates the fabrication of a chip pattern, immobilization of DNA to the particles and arrangement of the minute particle groups on the chip pattern by hydrophobic interaction.ophobic interaction.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.546-551
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• 2007

The present study numerically investigated the tube geometry and arrangement on the performance of a high temperature generator (HTG) of the double effect LiBr-water absorption system. FLUENT, as a commercial code, was used to estimate the thermal performance of the HTG. Key parameters were the spacing raito of circular and flattened tubes, the pitch ratio of the rib on the flattened tube, and total heat transfer area of the HTG. Temperature and velocity profiles around the tubes of the HTG were calculated to estimate the thermal performance of the HTG. When the spacing ratio of circular and flattened tube is 1.11 and 0.73, the exhaust gas temperature is $185^{\circ}C$ without rib. The exhaust gas temperature when applied the rib in flattened tubes was lower by $24^{\circ}C$ than that without the rib. Rib can reduce the HTG volume by 7%.

• 산업경영시스템학회지
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• 제45권1호
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• pp.41-52
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• 2022

Development of a long-range artillery intercept system to counter the threat of enemy long-range artillery is in progress. This intercept system is a complex combination of several components. In addition, the ability to engage simultaneously is emphasized due to the characteristic of having to respond to numerous enemy bullets. In this study, the performance according to the arrangement of the detection asset and missile launchers, which are key components of the system, is analyzed. A simulation experiment was performed assuming the enemy attack at various azimuth and launch angles. As a result of the analysis, the radar seems to provide sufficient detection capability in any situation, but in the case of the launcher, the effect of the enemy's launch angle can be critical. It is recommended to place both radar and launchers behind the protection target.

• Structural Engineering and Mechanics
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• 제59권3호
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• pp.387-401
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• 2016

This paper takes a half-through steel truss arch bridge as an example. A seismic analysis is conducted with nonlinear finite element method. Contrast models are established to discuss the effect of simplified method for main girder on the accuracy of the result. The influence of seismic wave direction and wave-passage on seismic behaviors are analysed as well as the superstructure and arch ring interaction which is mostly related with the supported bearings and wind resistant springs. In the end, the application of cable-sliding aseismic devices is discussed to put forward a layout principle. The main conclusions include: (1) The seismic response isn't too distinctive with the simplified method of main girder. Generally speaking, the grillage method is recommended. (2) Under seismic input from different directions, arch foot is usually the mostly dangerous section. (3) Vertical wave input and horizontal wave-passage greatly influence the seismic responses of arch ring, significantly increasing that of midspan. (4) The superstructure interaction has an obvious impact on the seismic performance. Half-through arch bridges with long spandrel columns fixed has a less response than those with short ones fixed. And a large stiffness of wind resistant spring makes the the seismic responses of arch ring larger. (5) A good isolation effectiveness for half-through arch bridge can be achieved by a reasonable arrangement of CSFABs.

• Asian-Australasian Journal of Animal Sciences
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• 제25권5호
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• pp.648-652
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• 2012

This study was conducted to determine the effects of dietary addition of tea saponins (TS) and soybean oil (SO) on fatty acid profile and gene expression of stearoyl-CoA desaturase (SCD) in longissimus dorsi (LD) muscle of growing lambs. Thirty-two Huzhou lambs were assigned to four dietary treatments in a $2{\times}2$ factorial arrangement with main effects of TS (0 or 3 g/d) and SO (0 or 30 g/kg of diet DM). The diet without additives was considered as NTNS (no TS or SO). After a feeding trial for 60 d, four lambs of each treatment were slaughtered to collect the samples of LD muscle. Percentage of trans-11 vaccenic acid was enhanced (p<0.05) in muscle of lambs fed TS and SO. The proportion of total conjugated linoleic acid (CLA) was increased (p<0.05) by SO, but decreased (p<0.05) by TS in LD muscle. The percentage of total saturated fatty acids in muscle was decreased (p<0.05) by addition of TS and SO, while addition of SO increased (p<0.05) the percentage of total polyunsaturated fatty acids. The ratio of cis-9, trans-11 CLA to tran-11 vaccenic acid was decreased (p<0.05) by TS, but increased (p<0.05) by SO. The same effects were observed in SCD mRNA expression. From these results it is indicated that including TS and SO in the diet of growing lambs affect the fatty acid profiles of LD muscle and that the proportion of cis-9, trans-11 CLA in the muscle influenced by TS and SO may be related to the SCD gene expression.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.381-396
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part I, finite element (FE) models establishment and validations for both the aircrafts and NPP buildings are performed. (i) Airbus A320 and A380 aircrafts are selected as the representative medium and large commercial aircrafts, and the corresponding fine FE models including the skin, beam, fuel and etc. are established. By comparing the numerically derived impact force time-histories with the existing published literatures, the rationality of aircrafts models is verified. (ii) Fine FE model of the Chinese Zhejiang Sanao NPP buildings is established, including the detailed structures and reinforcing arrangement of both the containment and auxiliary buildings. (iii) By numerically reproducing the existing 1/7.5 scaled aircraft model impact tests on steel plate reinforced concrete (SC) panels and assessing the impact process and velocity time-history of aircraft model, as well as the damage and the maximum deflection of SC panels, the applicability of the existing three concrete constitutive models (i.e., K&C, Winfrith and CSC) are evaluated and the superiority of Winfrith model for SC panels under deformable missile impact is verified. The present work can provide beneficial reference for the integral aircraft crash analyses and structural damage assessment in the following two parts of this paper.

• Geomechanics and Engineering
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• 제24권5호
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• pp.479-490
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• 2021

Pre-drainage of groundwater in the roof aquifer by boreholes is the main method for prevention of roof water disaster, and the drop in the water level during the drainage leads to the variation of the local stress in the overlying strata. Based on a multitude of boreholes for groundwater drainage from aquifer above the 1303 mining face of Longyun Coal Mine, theoretical analysis and numerical simulation are used to investigate the local stress variation in the process of borehole drainage. The results show that due to the drop in the water level of the roof aquifer during the drainage, the stress around the borehole gradually evolved. From the center of the borehole to the outside, a stress-relaxed zone, a stress-elevated zone, and a stress-recovered zone are sequentially formed. Along with the expansion of drainage influence, the stress peak in the stress-elevated zone also moves to the outside. When the radius of influence develops to the maximum, the stress peak position no longer moves outward. When the coal mining face advances to the drainage influence range, the abutment pressure in front of the mining face is superimposed with the high local stress around the borehole, which increases the risk of stress concentration. The present study provides a reference for the stress concentration caused by borehole drainage, which can be potentially utilized in the optimal arrangement of drainage boreholes in underground mining.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3775-3786
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• 2023

Mixing Vane Grid (MVG) is one of the most important structures in fuel assembly due to its high performance in mixing the coolant and ultimately increasing Critical Heat Flux (CHF), which avoids the temperature rising suddenly of fuel rods. To evaluate the mixing performance of the MVG, a Total Diffusion Coefficient (TDC) mixing coefficient is defined in the subchannel analysis code. Conventionally, the TDC of the spacer grid is obtained from the combination of experiments and subchannel analysis. However, the processing of obtaining and determine a reasonable TDC is much challenging, it is affected by boundary conditions and MVG geometries. In is difficult to perform all the large and costing rod bundle tests. In this paper, the CFD method was applied in TDC analysis. A typical 5 × 5 MVG was simulated and validated to estimate the mixing performance of the MVG. The subchannel code was used to calculate the TDC. Firstly, the CFD method was validated from the aspect of pressure drop and lateral temperature distribution in the subchannels. Then the effect of boundary conditions including the inlet temperature, inlet velocities, heat flux ratio between hot and cold rods and the arrangement of hot and cold rods on MVG mixing and TDC were studied. The geometric effects on mixing are also carried out in this paper. The effect of vane pattern on mixing was investigated to determine which one is the best to represent the grid's mixing performance.