• Korean Journal of Materials Research
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• v.2 no.3
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• pp.228-238
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• 1992

An investigation on the step-coverage of PECVD and $O_3$ ThCVD oxides was undertaken to implement into the void-free inter metal dielectric planarization using multi-chamber system for the submicron double level metallization. At various initial aspect ratios the instantaneous aspect ratios were measured through modelling and experiment by depositing the oxides up to $0.9{\mu}m$ in thickness in order to monitor the onset of void formation. The modelling was found to be in a good agreement with the observed instantaneous aspect ratio of TEOS-based PECVD oxide whose re-entrant angle was less than $5^{\circ}$. It is demonstrated that either keeping the instantaneous aspect ratio of PECVD oxide as a first layer less than a factor of 0.8 or employing Ar sputter etch to create sloped oxide edge ensures the void-free planarization after$O_3$ ThCVD oxide deposition whose step-coverage is superior to PECVD oxide. It has been observed that $O_3$ ThCVD oxide etchback scheme has shown higher yield of via contact chain than non etchback process, with resistance per via contact of $0.1~0.3{\Omega}/{\mu}m^2$.

• The Korea Journal of Herbology
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• v.21 no.2
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• pp.109-119
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• 2006

Objectives : This study was performed to approach of properties-flavours theory and the study of morphological standard in CORNI FRUCTUS. Methods : The properties-flavours theory were attempted with bibliographic method and various climate-information. The external-internal morphological standards were determined by using stereoscope and butanol series. Results and conclusion : 1. The significant analysis for the corni fructus as the properties-flavours theory, is a follow-up survey of the effect written in the official oriental medicine book. 2. The other analytic methods according to the gathering time, processing or storing system or especially nature or growth environment(altitude, temperature,. the mean moisture, and the agronomical survey) by way of the explanation of properties-flavours theory appears so many insufficiency at the many cases. 3. The external and internal characteristics according to the shape of original plant or herbal states, entirely correspond to all the literature on this subject. 4. According to the place of production, there are some different points. (l) In the external shapes, it is reasonable that if we make the basic standard of classification by the sharpness of color, the existence of gloss and the size of products. In the case of the Korean products, it shows bright and glossy color totally, but in the case of North Korea products, it shows black and lackluster. And in the case of the foreign products, it has softer body than Korea one and shows white color on the surface. (2) In the internal shapes, the Korea products has a thicker cuticle layer than the foreign one, and has fewer ca-oxalate in the parenchyma cell.

• Computational Structural Engineering
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• v.8 no.4
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• pp.87-97
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• 1995

For the same configuration of two-dimensional finite element models, 6-node element exhibits stiffer bending stiffness than 8-node element. This is true in the relation between 16-node element and 20-node element for three-dimensional model. This stiffening phenomenon comes from the elimination of several mid nodes from full-node elements. Therefore, this may be called 'relative stiffness stiffening phenomenon'. It seems that there are a couple of ways to correct the stiffening effect, however, we could find only one effective method-the method of modification of Gauss sampling points-which passes the patch test and does not alter other kinds of stiffness, such as extensional stiffness. The quantity of modification is a function of Poisson's ratios of the constituent materials. We could obtain two modification equations, one for plane stress case and the other for plane strain case. This method can be extended to 3-dimensional solid elements. Except the exact plane strain cases, most 3-dimensional plates could be modeled successfully with 16-node element modified by the equation for the plane stress case. The effectiveness of the modification method is checked by applying it to several examples with excellent improvements. In numerical examples, beams with various boundary conditions are subjected to static and time-dependent loads. Free and forced motion analyses of beams and plates are also tested. The beam and plate may be composed of isotropic multilayers as well as a single layer.

• Korean Journal of Crystallography
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• v.12 no.2
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• pp.70-75
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• 2001

The purpose of this study is to investigate the effect of V₂O/sub 5/ addition on physical and magnetic properties of NiCuZn ferrite for multi-layer chip inductors. NiCuZn ferrite pastes doped with 0, 0.1, 0.3 and 0.5 wt% V₂O/sub 5/ were prepared and samples of ferrite sheets were prepared by the screen printing method. They were sintered at 870, 880, 890 and 900℃, and then their physical and magnetic properties were analyzed. After sintering at 870℃, the sintered density of the ferrite sheet doped with 0.5wt% V₂O/sub 5/ showed the highest value to 5.08g/cm³due to the best densification by the liquid phase sintering, while the microstructures of ferrite sheets doped with 0.1 and 0.3 wt% V₂O/sub 5/ showed and inhibited grain growth. Irrespective of the sintering temperature, the initial permeability of ferrite sheet doped with 0.5 wt% V₂O/sub 5/ was highest and after sintering beyond 880℃, the quality factor of 0.3 wt% V₂O/sub 5/-doped sample appeared to be highest.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.407-414
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• 2013

This study was conducted to classify forest cover types using the multivariate statistical analysis in the natural forest of western Mt. Jiri. On the basis of the vegetation data by point quarter sampling, the adopted analytical methods were species-area curve (SAC), hierarchical cluster analysis (HCA), indicator species analysis (ISA), and multiple discriminant analysis (MDA). SAC selected the outlier tree species which was likely to have no influence on the classification of forest cover types, excluded from all analytical process. Based on forest vegetative information, HCA classified the study area into 2 to 10 clusters and ISA indicated that the optimal number of clusters were seven. MDA was taken to test the clusters that classified with HCA and ISA. The seven clusters were classified appropriately as overall classification success were 91.3%. The classified forest cover types were named by the ratio of the dominant species in the upper layer of each cluster. They were (1) Quercus mongolica Pure forest, (2) Mixed mesophytic forest, (3) Q. mongolica - Q. serrata forest, (4) Abies koreana - Q. mongolica forest, (5) Fraxinus mandshurica forest, (6) Q. serrata forest, and (7) Carpinus laxiflora forest.

• Journal of Gastric Cancer
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• v.4 no.4
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• pp.282-285
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• 2004

We report a case of advanced gastric cancer with Virchow's node and lung metastasis that responded remarkably to preoperative chemotherapy. A 47-year-old female patient was diagnosed as having incurable advanced gastric cancer with Virchow's node and multiple lung metastasis. Preoperative chemotherapy with Taxotere, CDDP and 5FU was carried out. After four courses of the regimen, the Virchow's node and the lung metastasis had disappeared, and a marked reduction of the gastric lesion was observed on the CT scan. Consequently, the patient underwent a total gastrectomy with D2 lymph node dissection. On histopathological examination, cancer cells were found to have infiltrated up to the muscle layer of the gastric wall, and 42 out of 60 resected lymph nodes were found to be metastatic. The patient received another two courses of chemotherapy after the operation. (J Korean Gastric Cancer Assoc 2004;4:282-285)

• KSBB Journal
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• v.21 no.6 s.101
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• pp.422-427
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• 2006

The culture media from Fomitopsis pinicola were extracted by methanol and examined growth inhibition against Helicobacter pylori. The culture media from 8 days fermentation of F. pinicola showed maximum inhibition activity on H. pylori in 0.25 mg as MIC value. The highest activity against H. pylori by MHCS agar diffusion medium by Fp-P1 in 22.7 mm ID among 3 peaks from methanol fraction of 8 days culture media of Fomitopsis pinicola which purified by ion-exchange chromatography. The Fp-P1 from DEAE-Sephadex A-25 have been analysed by TLC as Fp-T1, Fp-T2 and Fp-T3 by ninhydrin staining. Fp-T3 (Rf value : 0.67) was higher activity against H. pylori in 14.4 mm ID. Fp-T3 was identified as single band by HPLC and TLC. It was assumed to aminosugar by BioLC analysis and TLC staining.

• Journal of the Korea Computer Graphics Society
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• v.24 no.2
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• pp.21-28
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• 2018

We present interactive methods for visualizing the cloud height data and the backscatter data collected from ceilometers in the three-dimensional virtual space. Because ceilometer data is high-dimensional, large-size data associated with both spatial and temporal information, it is highly improbable to exhibit the whole aspects of ceilometer data simply with static, two-dimensional images. Based on the three-dimensional rendering technology, our visualization methods allow the user to observe both the global variations and the local features of the three-dimensional representations of ceilometer data from various angles by interactively manipulating the timing and the view as desired. The cloud height data, coupled with the terrain data, is visualized as a realistic cloud animation in which many clouds are formed and dissipated over the terrain. The backscatter data is visualized as a three-dimensional terrain which effectively represents how the amount of backscatter changes according to the time and the altitude. Our system facilitates the multivariate analysis of ceilometer data by enabling the user to select the date to be examined, the level-of-detail of the terrain, and the additional data such as the planetary boundary layer height. We demonstrate the usefulness of our methods through various experiments with real ceilometer data collected from 93 sites scattered over the country.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.2
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• pp.41-47
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• 2010

The effect of PCB and BGA pad designs was investigated on the mechanical property of Pb-free solder joints. The mechanical property of solder joint was tested by three different test methods of drop impact tests, bending impact test, and high speed shear test. Two kinds of pad design such as NSMD (Non-Solder Mask Defined) and SMD (Solder Mask Defined) were applied with the OSP finished Pb-free solder (Sn-3.0Ag-0.5Cu, Sn-1.2Ag-0.5Cu). in the drop impact test and bending impact test, the characterized lifetime showed the same tendency, and SMD design showed better mechanical property of solder joint than NSMD regardless of test method, which was due to the different crack path. The fracture crack on SMD pad was propagated along the intermetallic compound (IMC) layer of solder joint, while the fracture crack on NSMD pad propagated through upper edge of land which shields pattern. In the high speed shear test, pad lift occurred on the solder joint of NSMD. SMD/SMD combination of pad design consequently illustrated the best mechanical property of BGA/PCB solder joint, followed by SMD/NSMD, NSMD/SMD, and NSMD/NSMD.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.1-6
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• 2014

Flip chip bonded LED packages possess lower thermal resistance than wire bonded LED packages because of short thermal path. In this study, thermal and bonding properties of flip chip bonded high brightness LED were evaluated for Au-Sn thermo-compression bonded LEDs and Sn-Ag-Cu reflow bonded LEDs. For the Au-Sn thermo-compression bonding, bonding pressure and bonding temperature were 50 N and 300oC, respectively. For the SAC solder reflow bonding, peak temperature was $255^{\circ}C$ for 30 sec. The shear strength of the Au-Sn thermo-compression joint was $3508.5gf/mm^2$ and that of the SAC reflow joint was 5798.5 gf/mm. After the shear test, the fracture occurred at the isolation layer in the LED chip for both Au-Sn and SAC joints. Thermal resistance of Au-Sn sample was lower than that of SAC bonded sample due to the void formation in the SAC solder.