• Journal of Magnetics
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• v.6 no.3
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• pp.80-82
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• 2001

We have investigated magnetism of $Fe_2 /Ir_4$(001) superlattice in terms of a first-principles calculation by using an all-electron full-potential linearized augmented plane-wave (FLAPW) method within the generalized gradient approximation (GGA). We considered two magnetic states, the ferromagnetic (FM) and antiferromagnetic (AFM) coupled states between the Fe layers. It was found that the FM state was energetically more stable than the AFM one by 0.166 eV. Calculated magnetic moments of the Fe layers were, in absolute values, 2.45$\mu_B$ and 2.30 $\mu_B$for the FM and AFM states, respectively. We also found that the Ir layers had very small magnetic moments less than 0.1 $\mu_B$ for both magnetic states. In all the magnetic states, the subinterface Ir layers were coupled antiferromagnetically to the interface Ir layers, while the interface Ir layers were always coupled frerromagnetically to the interface Fe layers. These results contradicted to recent experimental reports of magnetically "dead"Fe layers in Fe/Ir superlattices for which the Fe layer thickness was less than two atomic layers. We attributed that the experimentally observed "dead"Fe layers were due to possible interdiffusion between Ir and Fe layers.en Ir and Fe layers.

• Journal of Korean Society of Rural Planning
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• v.14 no.4
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• pp.11-19
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• 2008

The layer technique is to produce many memorable scenes by generating layers of new experiences on the existing ones as it is adding the cognitive layers on to the visually seen landscape. Its need is high for places whose landscape itself influences perception, value or expression and which determines the spatial and quality standards. The existing floor plan-based design methods have failed to be useful in generating complex visual experiences. In order to maximize the aesthetical landscape experiences in landscape planning, cognitive layers are needed which complement the input of adequate cognitive elements and the inter-element relationships. Here, layers are utilized to change the arrangement of the landscape elements and coordinate the cognitive flow so that the images could be connected and imagination could occur. A case in point is Anhyun Village in Gochang where physically distinctive layers are additionally set to make a visual experience enriching. The new landscape layers discover the fact that it provides diversity in experiencing the village landscape and forming the sense of beauty and that it is deeply immersed into the daily life of the village. Meanwhile, Guwau Village in Taebaek is an example showing the usefulness of various-layer setting in landscape planning in setting effective circulation planning. That is, the bottom line is the spacing-starting where and making it stay where for a few seconds, and the visual layers. It is also critical to encourage inducing circulation so that layers of the senses stimulating five senses could intervene. Lastly, Mulgeon-ri in Namhae is a case which directly made a parallel of the physical layers of the landscape composition and the cognitive layers of the landscape experience. Artificial landscape planning is mostly about manipulating of visual traits that people feel beautiful, but the layer technique is linked to how to make experiences enriching and renewed.

• Korean Journal of Poultry Science
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• v.25 no.3
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• pp.119-128
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• 1998

On account of the recent improvement in performance of brown layers, the market share taken by brown layers has increased to about 50% in the world and to almost 100% in Korea. There are several other reasons why the industry has moved from white to brown, such as : brown layers are used to be more robust, more docile and easier to manage ; e brown layers are easier to sex at the hatchery ; brown layers lay less second grade eggs, due to a better shell Quality ; brown eggs seem to be more attractive than white ; and a clear consumer preference, thus a better price per egg. More recently, however, the trend towards brown eggs has been slowing down. The main reasons for this lie in that white layers can still produce an egg at a lower cost and that white eggs have better de-shelling properties, easier candling and higher yolk and solid content of the liquid egg which are benefits for egg processing industry. Although the performance of the brown layers is still improving, there are increasing opinions in the poultry industry that the market portion of white layers should be increased based on the following reasons, such as : shell color has no effect on the nutritive value of eggs ; . brown layers consume more feed ; the percentage of meat spots is significantly higher in brown eggs than in white eggs ; . brown layers are less efficient in the second cycle of production than in the first ; white layers are more resistant to the disease of fowl typhoid. In order to increase the market share of white layers in Korea, it may be needed to enlighten the consumers not to prefer the brown and large eggs and to inform the excellencies of white eggs widely.

• Journal of Powder Materials
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• v.20 no.1
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• pp.24-32
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• 2013

The effect of carrier gases (He, $N_2$) on the properties of Ti coating layers were investigated to manufacture high-density Ti coating layers. Cold spray coating layers manufactured using He gas had denser and more homogenous structures than those using $N_2$ gas. The He gas coating layers showed porosity value of 0.02% and hardness value of Hv 229.1, indicating more excellent properties than the porosity and hardness of $N_2$ gas coating layers. Bond strengths were examined, and coating layers manufactured using He recorded a value of 74.3 MPa; those manufactured using $N_2$ gas had a value of 64.6 MPa. The aforementioned results were associated with the fact that, when coating layers were manufactured using He gas, the powder could be easily deposited because of its high particle impact velocity. When Ti coating layers were manufactured by the cold spray process, He carrier gas was more suitable than $N_2$ gas for manufacturing excellent coating layers.

• Culinary science and hospitality research
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• v.7 no.2
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• pp.123-132
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• 2001

The contents of the pastry margarine were 30, 50, 70, 90 and 110% based on baker's %, and the layers of the dough were 18, 27, 36, 48 and 64 in danish pastry product In order to analyse on the effect of the theoretical one layer thickness of the pastry margarine, the volume, quality and sensory evaluation of the products have been carried out. The results as follows ; 1) Best volume was showed that the thickness of the dough was 5mm and the thickness of one layer was 0.039mm. 2) When the content of the pastry margarine was 30% and the thickness of one layer was 0.014mm(48 layers), when 50%, 0.039mm(27 layers), when 70%, 0.038(36 layers), when 90%, 0.034(48 layers) and when 110%, 0.039(48 layers), best volume was showed. 3) In the case when the content of pastry margarine was 70% and the thickness of one layer was 0.038mm(36 layers), as well as 110%, 0.039mm(48 layers), the taste were showed 5%, better than when 30%, 0.014(27 layers) in the sensory evaluation. Flavor and mouth feel was the same results. 4) For the best quality products, the content of the pastry margarine and the layers of the dough were very important.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.70-75
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• 2011

We introduced nanoscale interfacial layers between the PV layer and the cathode in poly (3-hexylthiophene):methanofullerene bulk-heterojunction polymer photovoltaic (PV) cells. The nanoscale double interfacial layers were made of ultrathin poly (oxyethylenetridecylether) surfactant and low-work-function alloy-metal of Al:Li layers. It was found that the nanoscale interfacial layers increase the photovoltaic performance, i.e., increasing short-circuit current density and fill factor with improved device stability. For PV cells with the nanoscale double interfacial layers, an increase in power conversion efficiency of $4.18{\pm}0.24%$ was achieved, compared to that of the control devices ($3.89{\pm}0.08%$) without the double interfacial layers.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.3
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• pp.43-48
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• 2001

The stability and efficiency of organic light emitting devices are the most critical problems to be solved. The devices based on tris-8-(hydroxyquinoline) aluminum ($Alq_3$) and N,N-diphenyl-N,N-bis(3-methylphenyl)-1, 1-biphenyl-4,4-diamine (TPD) were used to study the effects of buffer layers on their characteristics. We have investigated the characteristic effects of CuPc (copper phthalocyanine) and pentacene buffer layers on the device characteristics, the (5${\sim}$20 nm thick) CuPc layers and the (10${\sim}$20 nm thick) pentacene layers were deposited. Efficiency was slightly improved and the turn-on voltages of the devices with the buffer layers were observed to have lower values than those of the devices without the buffer layers. It is believed that this result is attributed to the improvement of hole injection capability through the buffer layers into hole transport layer (HTL). We have also studied the atomic force microscopic images of the TPD layers deposited on the buffer layer and the bare ITO.

• Geomechanics and Engineering
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• v.14 no.2
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• pp.115-129
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• 2018

This paper presents a set of results of plate load tests that imposed incremental cyclic loading to a sandy soil bed containing multiple layers of granulated rubber-soil mixture (RSM) at large model scale. Loading and unloading cycles were applied with amplitudes incrementally increasing from 140 to 700 kPa in five steps. A thickness of the RSM layer of approximately 0.4 times the footing diameter was found to deliver the minimum total and residual settlements, irrespective of the level of applied cyclic load. Both the total and residual settlements decrease with increase in the number of RSM layers, regardless of the level of applied cyclic load, but the rate of reduction in both settlements reduces with increase in the number of RSM layers. When the thickness of the RSM layer is smaller, or larger, settlements increase and, at large thicknesses may even exceed those of untreated soil. Layers of the RSM reduced the vertical stress transferred through the foundation depth by distributing the load over a wider area. With the inclusion of RSM layers, the coefficient of elastic uniform compression decreases by a factor of around 3-4. A softer response was obtained when more RSM layers were included beneath the footing damping capacity improves appreciably when the sand bed incorporates RSM layers. Numerical modeling using "FLAC-3D" confirms that multiple RSM layers will improve the performance of a foundation under heavy loading.

• Computers and Concrete
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• v.26 no.5
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• pp.377-384
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• 2020

A two-dimensional particle flow cod (PFC) is used to study the effect of missile impact on the concrete target. For this purpose firstly calibration of numerical model was performed so that tensile strength of numerical models and experimental sample were the same. Secondly, a concrete model was built. The number of concrete layers and the angle of concrete layers related to horizontal axis were changed. Their numbers were 1, 2, 3 and 4. The angles were 0°, 15°, 30°, 45°, 60°, 75° and 90°. A semi-circle missile was simulated at top of the concrete layers. Its velocity in opposite side of Y direction was 100 m/s. three measuring circles were situated at the below the missile in the model to receive the applied force. The load in the missile and measuring circles together with failure pattern were registered at the beginning of the impaction. The results show that concrete layers number and concrete layers angle have important effect on the failure load while the failure pattern was nearly constant in all of the models.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.181-186
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• 2007

UBM (Under Bump Metallurgy) of flip chip assemblies consists of several layers such as the solder wetting, the diffusion barrier, and the adhesion layers. In addition, IMC layers are formed between the solder wetting layers (e.g. Cu, Ni) and the solder. The primary failure mechanism of the solder joints in flip chips is widely known as the fatigue failure caused by thermal fatigues or electromigration damages. Sometimes, the premature brittle failure occurs in the IMC layers. However, these phenomena have thus far been viewed from only experimental investigations. In this sense, this paper presents a method for solid modeling of IMC layers in flip chip assemblies, thus providing a pre-processing tool for finite element analysis to simulate the IMC failure mechanism. The proposed modeling method is CSG-based and can also be applied to the modeling of UBM structure in flip chip assemblies. This is done by performing Boolean operations according to the actual sequences of fabrication processes