• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.67-74
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• 2014

An inverter scroll compressor is used for the air conditioning in cars. Scrolls would be changed from the aluminum material to the magnesium material in order to satisfy the light weight trends of cars. The material changing influences on the scroll dimensions particularly the gap between two scrolls. Since the larger gap declines the performance of the compression, the gap between wraps of scrolls or the gap between wraps of scrolls to the plate of the opposite scroll is regarded as an important design variable. This paper is focused on the effects of the thermal stress due to the materials changing. The temperature difference between the inlet and the outlet is about 60 degrees and the highest operating temperature in the compressor is less than 110 degrees. The level of thermal stresses in the magnesium scroll is less than the result from aluminum one. The trend of the deformation is revealed that the normal directional deformation is 2 times lager than the in-plane directional deformation. Therefore the gap between the top of the wrap to the plate of the opposite scroll become more important than the other gaps. The orbiting scroll deforms larger than the fixed scroll by the thermal stresses. The deformation of the magnesium scroll is about 10% lager than that of the aluminum scroll. This value is similar to the ratio of the coefficients of thermal expansion of two materials. At the initial design stage, the results give many useful guides to engineers to propose gaps between parts.

• Geophysics and Geophysical Exploration
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• v.9 no.2
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• pp.148-154
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• 2006

The effect of small-scale near surface inhomogeneity on Rayleigh wave propagation and dispersion has been investigated in this study using two-dimensional FEM elastic modeling. Various inhomogeneity models with a variety of geometrical shape and embedment depth which exist in homogeneous half-space and two-layered media are considered. Results show that any near surface inhomogeneity greater than one wavelength in terms of minimum wavelength of Rayleigh wave shows dispersion characteristics. Such dispersion effect become stronger as the dimensions of the inhomogeneity increase. The effect of horizontal dimension is more dominant factor governing the dispersion characteristics than vertical dimension. However, the dispersion effect can not be identifiable in seismogram if the horizontal dimension is not wide enough. Nonetheless, even in this case, the existence of inhomogeneity can be inferred by the reflection or transmission event of Rayleigh wave. The results can be expected to provide insights on the behavior of Rayleigh wave which may be helpful for designating field work or new processing scheme to detect near surface inhomogeneity by surface wave method.

• Korean Journal of Crystallography
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• v.15 no.2
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• pp.78-82
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• 2004

The solvothermal reaction of zinc(H) nitrate $(Zn(NO_3)_2\;{\cdot}\;6H_2O)$ with $ATP(2-aminoterephthalate,\;H_2N-C_6H_3-1,4-(COO)_2)$ in a mixture of solvents of DMF and ethanol, in the presence of benzene, gave a 2 dimensional zinc polymer [Zn(ATP) (DMF)] (1). X-ray structure determination revealed that two zinc metals and four ATP ligands form the paddle-wheel SBUs, which are linked by the ATP ligands to give a 2-D square-grid network. Each square grid has approximate dimensions of $11.1\times11.1\;{\AA}$ based on Zn metals. Benzene was required to produce high-quality crystals of polymer 1.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.179-191
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• 2013

The quincunx lattice is a non-separable sampling method in image processing. It treats the different directions more homogeneously and good frequency property than the separable two dimensional schemes. The high density discrete wavelet transformation is one that expands an N point signal to M transform coefficients with M > N. In two dimensions, this transform outperforms the standard discrete wavelet transformation in terms of shift-invariant. Although the transformation utilizes more wavelets, sampling rates are high costs. This paper proposed the high density discrete wavelet transform using quincunx sampling, which is a discrete wavelet transformation that combines the high density discrete transformation and non-separable processing method, each of which has its own characteristics and advantages. Proposed wavelet transformation can service good performance in image processing fields.

• Proceedings of the Korea Association of Information Systems Conference
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• 2004.11a
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• pp.201-208
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• 2004

Many organizations experience that the Performance they gained from IT portfolio is lower than they expected values. As with any investment, executives are concerned with maximizing the performance from their investment in IT. This study focused on the relationship or fit between orientations of IT strategy and directions of IT portfolio to maximize IT performance. A field survey of chief information officers of Korea manufacturing sector was conducted in 2003. Complete data of 147 firms was analyzed to determine relationship among the three research constructs that are orientations of IT strategy, directions IT portfolio, and IT performance. In this study, the orientations of IT strategy have two dimensions that are operation orientation and market orientation. The directions of IT portfolio have two dimension that are internal system focused and external system focused. And the IT performance has divided into operational performance and competitive performance. As a result of this study, the companies that are putting a focus with operation orientation were concentrated on internal information systems than external information systems. On the other hand, the other companies that are focused on market orientation were concentrated on external information systems than internal information systems. Consequently, the companies that are focused on operation orientation were operational performance higher than competitive performance and the other companies that are focused on market orientation were competitive performance higher than operational performance. More importantly, the research results provide empirical evidence that supports the hypothesis related to closer fit between IT strategy and IT portfolio does lead to increase operational and competitive performance of IT. And the results emphasize manager's efforts of fit between orientations of IT strategy and directions of IT portfolio to be realized IT performance.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.568-572
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• 2006

To study the effect of sequence on DNA structure, the two decamer crystal structures one alternating,d(GTACGCGTAC), and the other non-alternating, d(GGCCGCGGCC), were solved. Crystals of both decamers belong to the hexagonal space group $P6_122$, with one strand in the asymmetric unit. The unit cell constants of the alternating decamer are a = b = 39.26 $\AA$, c = 77.70 $\AA$. The structure was refined with 1,828 reflections from 8.0 to 2.0 Aresolution to an R value of 21.3% with all DNA atoms and 63 water molecules. The isomorphous non-alternating decamer had unit cell dimensions of a = b = 39.05 $\AA$, c = 82.15 $\AA$. The structure was refined with 2,423 reflections from 8.0 to 2.0 $\AA$ resolution to a final R value of 22.2% for all DNA atoms and 65 water molecules. Although the average helical parameters of the decamers are typical of A-DNAs, there are some minor differences between them. The helical twist, rise, x-displacement, inclination and roll alternate in the alternating decamer, but do not in the non-alternating decamer. The backbone conformations in both structures show some differences; the residue G(7) of the alternating decamer is trans for $\alpha$ and $\gamma$ while the trans conformations are observed at the residue G(8) of the non-alternating decamer.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.31-38
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• 2011

In this study, in order to observe the behaviors of fiber reinforced polymer (FRP) strengthened and steel fiber reinforced concrete specimens for impact and static loads, flexural and punching tests were performed. For the one-way flexural and two-way punching tests, concrete specimens with the dimensions of $50{\times}100{\times}350$ mm and $50{\times}350{\times}350$ mm were fabricated, respectively. The steel fiber reinforced concrete specimens showed much enhanced resistance on two-way punching of static and impact loads. In addition the FRP strengthening system provided the outstanding performance under a punching load. Because of a large tensile strength and toughness of ultra high performance concrete (UHPC), the UHPC specimens retrofitted with FRP showed marginally enhanced strength and energy dissipating capacity.

• The korean journal of orthodontics
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• v.45 no.3
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• pp.105-112
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• 2015

Objective: A recently developed facial scanning method uses three-dimensional (3D) surface imaging with a light-emitting diode. Such scanning enables surface data to be captured in high-resolution color and at relatively fast speeds. The purpose of this study was to evaluate the accuracy and precision of 3D images obtained using the Morpheus 3D$^{(R)}$ scanner (Morpheus Co., Seoul, Korea). Methods: The sample comprised 30 subjects aged 24.34 years (mean $29.0{\pm}2.5$ years). To test the correlation between direct and 3D image measurements, 21 landmarks were labeled on the face of each subject. Sixteen direct measurements were obtained twice using digital calipers; the same measurements were then made on two sets of 3D facial images. The mean values of measurements obtained from both methods were compared. To investigate the precision, a comparison was made between two sets of measurements taken with each method. Results: When comparing the variables from both methods, five of the 16 possible anthropometric variables were found to be significantly different. However, in 12 of the 16 cases, the mean difference was under 1 mm. The average value of the differences for all variables was 0.75 mm. Precision was high in both methods, with error magnitudes under 0.5 mm. Conclusions: 3D scanning images have high levels of precision and fairly good congruence with traditional anthropometry methods, with mean differences of less than 1 mm. 3D surface imaging using the Morpheus 3D$^{(R)}$ scanner is therefore a clinically acceptable method of recording facial integumental data.

• Imaging Science in Dentistry
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• v.46 no.2
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• pp.109-115
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• 2016

Purpose: Sinus elevation procedures have become a routine and reliable way to gain bone volume in the edentulous maxilla for dental implant placement. Presence of bony septations and pathology in the maxillary sinus often cause complications leading to graft or implant failure or both. The aim of this study was to retrospectively evaluate the prevalence of pathology, direction of the septa, and sinus width measured at 2 mm, 5 mm, and 10 mm from the sinus floor in maxillary sinuses using cone-beam computed tomography (CBCT). Materials and Methods: Seventy-two sinuses from 36 random preoperative CBCT scans referred for implant therapy were retrospectively evaluated for the number, prevalence, and direction of bony septations and presence of pathology. Width of the sinus was also measured at 2 mm, 5 mm, and 10 mm from the sinus floor to account for the amount of bone available for implant placement. Results: Maxillary sinus septa were found in 59.7%. Presence of a single septum was noted in 20 sinuses (27.7%), followed by two septa in 17 sinuses. The most common direction of the septum was the transverse direction. Retention pseudocyst and mucosal thickening were the most commonly seen abnormality/pathology. Conclusion: Based on the high prevalence of septa and sinus pathology in this sample, a preoperative CBCT scan might be helpful in minimizing complications during sinus augmentation procedures for dental implant therapy.

• Journal of The Korean Association For Science Education
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• v.31 no.6
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• pp.998-1008
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• 2011

The purpose of this study is to develop the criteria for measuring the observation abilities of elementary school students. Object, viewpoint and mental demand constitute the evaluation criteria of observation abilities. Object domain was classified into two- and three-dimensional figures, while viewpoint was classified into constancy and variety of views. Mental demand covered 2 through 5. The assesment tool based on the threedimensional criteria was developed for the lower, middle and upper grades of 166 elementary school students. Results from this study were as follows. These students' scores were significantly different in the classification by each dimension and distinguishable between the grades. They scored high on two-dimensional figures, constancy of view and lower mental demand, and the upper grade students' scores were higher than the lower ones in all dimensions. Therefore, the evaluation criteria developed in this study can be used effectively for measuring the observation abilities of elementary school students. Implication for this study was determined to be the development of a valid and reliable test for observation abilities of elementary school students.