• Journal of the Korean Chemical Society
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• v.52 no.2
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• pp.164-168
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• 2008

CaWO4 crystals were synthesized by a microemulsion method. Various sizes and shapes of CaWO4 were obtained by changing the molar ratio (w) of H2O to CTAB. At w=5 and 10, oval CaWO4 crystals with length of 100 nm and 500 nm were obtained, respectively. At w=20, rod-like CaWO4 crystal with length of 1 μm was obtained. The sphere CaWO4 crystal with length of about 2~3 μm was obtained at w=30. The CaWO4 crystal morphology changes from oval to sphere via a rod by aggregation with increasing the molar ratio of H2O to CTAB.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.2
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• pp.4096-4104
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• 1976

This experiment was carried out to investigate the efficient turning method which will be able to use every cutting methods, to calculate the width of the center field which must transpose from rotary cutting method to return cutting method, to investigate the effects of L/W and unit field on the operation efficiency. The results are summarized as follows: 1. In case of cutting in the outer field, the efficient turning method is the "$\alpha$" type turning method (half U-shaped turning method) at the first rotation, is the "$\beta$" type turning method (T-shaped turning method) at the second to fourth rotation. 2. In case of cutting in the inner field, the efficient turning method which takes the least turning time is the "a" type turning method ($\Delta$-shaped turning method). 3. The width of the center field (W') changes by the length-width ratio (L/W) and width (W), W' is 9.0m in case that L/W is 2.5 and W is 30m. 4. The larger L/W and area of unit field (A) become, the more operation efficiency (E) increases, and the limits that E is affected signicantly by L/W is 2 to 3.5 and A is within 5,000$m^2$. within 5,000$m^2$.

• Journal of Powder Materials
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• v.14 no.3 s.62
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• pp.208-214
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• 2007

The microstructure and hardness of (W,Ti)C cemented carbides with a different metallic binder composition of Ni and Co fabricated by powder technology were investigated. The densifications of the prepared materials were accomplished by using vacuum sintering at $1450^{\circ}C$. Nearly full dense (W,Ti)C cemented carbides were obtained with a relative density of up to 99.7% with 30 wt.% Co and 99.9% with 30 wt.% Ni as a metallic binder. The average grain size of the (W,Ti)C-Co and the (W,Ti)C-Ni was decreased by increasing the metallic binder content. The hardness of the dense (W,Ti)C-15 wt%Co and (W,Ti)C-15 wt%Ni, was greater than that of the other related cemented carbides; in addition, the cobalt-based cemented carbides had greater hardness values than the nickel-based cemented carbides.

• The Journal of Fisheries Business Administration
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• v.34 no.1
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• pp.87-115
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• 2003

Korean fisheries societies have had many difficulties for economic, social, and living circumstances. The government has tried many projects to improve these circumstances. But the results of the projects did not come up to his expectation. Recently, blue tourism is emerging as an alternative for improving these circumstances. So we applied a tourism value chain model for identifying what value activities and resources needed. According to the tourism value chain model, it was identified that there were six different value activities, i. e. advertising, reserving, moving, experiencing, returning, and after services of blue tourism. To identify which of the resources are sufficient or not in Korean blue tourism, we compared the required resources with actual ones. It was identified that Korean fisheries societies have so sufficient H/W related resources, but not IT related S/W resources, humanware-based resources, some industrial H/W resources and sociocultural resources. Therefore, Korean blue tourism will be activated, we have to concentrate our efforts on supplementing some scant blue tourism resources, i.e. S/W and humanware related resources and developing a variety of tourism programs to H/W resources. Generally, sustainable tourism needs all of S/W, H/W, and humanware resources. So we suggest several policies for the aspects of S/W, H/W, and humanware resources to activate blue tourism. But before carrying these policies out, they should be tested by field studies. And tourism motivations will be also studied because effective tourism marketing is impossible without an understanding of consumers' motivations.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.72-80
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• 1996

This paper presetns the development of a SSPA operating at KU-band(14~14.5 GHz) in order of replace TWTA used in the terrestria transponder of a satellite communication. The driving stage of SSPA uses internally matched 2W, 4W, 8W FET and the power stage is coupled with two internally matched 8W FET by branch-line cominer. The SSPA is fabricated with oth the RF circuit and the bias circuitry operating temperature compensation, regulation and sequence on aluminum housing. The SSPA testing resutls implemented in this way show 24.8$\pm$1dB small-signal gain, 41dBm P1dB power, a typical two tone C/IM3, -33dBc with single carrier backed off 6dB from p1dB, and gain stability over temeprature (-30~50)$\pm$1dB.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.38-49
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• 1985

The water soluble organic fractions (WSOF) from an agricultural soil (W), a soil treated with sludge for 6 years ($WS_6$), a sludge-soil mixture incubated for one week ($WS_1$), and sewage sludge (SS) were extracted, purified, and characterized by elemental analysis, functional group determinations, infrared, UV-visible, and proton nuclear magnetic resonance spectrosocpy. The SS was characterized by higher organic H, N, and P contents, a higher H/C ratio, and a lower C/N ratio than W. Total acidity carboxyl and phenolic hydroxyl group contents were generally highest in SS, intermediate in $WS_6$ and $WS_1$, and lowest in W. Overall aromatic character and aromatic carboxyl group contents were highest in W, and lowest in SS. Aliphatic proton, aliphatic carboxyl, and phenolic hydroxyl group contents were highest in SS, and lowest in W. Protein decomposition products were the pronounced components in SS, and decreased in concentration as the sludge component in the mixtures decreased. The $^1H$-NMR spectra suggested that the SS-protons were bound to a wider range of functional groups than W-protons. Structural complexities around the aromatic protons followed the following order: SS>$WS_1$>$WS_6$>W.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.753-759
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• 1999

The microstructure and electrical properties of ZNR that W $O_3$ is added in the range 0.5~4.0mol%, were investigated. The major part of W $O_3$ were segregated at the nodal point and W-rich phase was formed. Three crystalline phases, such as W-rich phase (W $O_3$), Bi-rich phase (B $i_2$W $O_{6}$ ), and spinel phase (Z $n_{2.33}$S $b_{0.67}$ $O_4$) were confirmed to be co-existed at the nodal point The average grain size increased in the range 15.5~29.9$\mu\textrm{m}$ with increasing W $O_3$ additive content. Consequently. W $O_3$ acted as a promotion additive of grain growth. As the W $O_3$ additive content increases. the varistor voltage and the nonlinear exponent decreased in the range 186.82~35.87V/mm and 20.90~3.34, respectively, and the leakage current increased in the range of 22.39~83.01 uh. With increasing W $O_3$ additive content, the barrier height and the density of interface states decreased in the range 1.93~0.43eV and (4.38~1.22)$\times$10$^{12}$ $\textrm{cm}^2$, respectively. W $O_3$ acted as an acceptor additive due to the donor concentration increasing in the range (1.06~0.38)$\times$10$^{18}$ /㎤with increasing W $O_3$ additive content.t.t.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1517-1527
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• 2020

This study is about the UV protection effect and water resistance of a multiple emulsion (W/O/W) sunblock cream applied with emotional engineering and reports an actual industrial case. Multiple emulsion system of sunblock cream has the characteristics of changing to a W/O type that is soft and moist when applied, and has excellent water resistance after absorption. Multiple emulsion cream is a highly functional sunblock cream that has both moisture and water resistance. It is a stable milky white cream with a viscosity of 36,000 cps. The organic sunscreen used for the sunscreen was ethylhexylmethoxycinnamate and bisethylhexyloxyphenolmethoxyphenyltriazine. Hexagonal zinc oxide and titanium dioxide that block both UVB and UVA were used. As a result of measuring the UV protection effect by the in-vitro method, the UV protection effect (SPF) is 78.9 for multiple emulsion cream, 76.7 for W/O cream, and 71.3 for O/W cream. It was found that the blocking effect was different. This obtained the highest effect value in the multiple emulsion. As a clinical (in-vivo) result of the UV protection effect, the SPF value representing the UV protection effect of the sunblock cream developed with a multiple emulsion system was 85.7, and the PA-value that blocks the UVA area was 26.5, and ++++. It was found that it has a corresponding high blocking effect. As a result of the water resistance test, the W/O/W formulation had a high waterproofing resistance of 93.8% even after 4 hours, W/O had 75.4%, and O/W had a low water resistance of 25.3%. In the results of the HUT test, it was found in the order of multiple emulsion sun block cream > hydrophilic cream > lipophilic cream. Based on the research results of this multiple emulsion, it is expected to be highly active as a sunblock cream dedicated to outdoor activities by improving the feeling of use, UV protection index, and water resistance. Therefore, in this study, a multiple emulsion system of sunblock cream is developed and has a characteristic that changes to a W/O type that has a soft and moist feeling when applied, and has excellent water resistance after absorption.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.344-344
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• 2011

W(110)면에 흡착원자인 Al원자의 coverage와 annealing과정에서의 온도를 변화시켜, 여러 조건에서의 Al/W(110)계의 흡착구조를 저에너지 전자회절(LEED)과 이온산란분광법(ISS-TOF)을 이용하여 연구하였다. 여러 결과 중, annealing 온도가 900K인 1.0ML Al/W(110)면은 double domain의 p($1{\times}1$)의 흡착구조로 W(110)면의 center of hollow site에서 $0.55{\AA}$ 벗어난 위치에 흡착되었으며, W(110) 표면원자로부터 Al 원자까지의 높이는 $2.13{\pm}0.15{\AA}$이다. 또한 annealing 온도가 1100K인 0.5ML Al/W(110)면은 double domain의 p($2{\times}1$)의 흡착구조로 W(110)면의 center of bridge site에 흡착되었으며, W(110) 표면원자로부터 Al 원자까지의 높이는 $2.18{\pm}0.15{\AA}$이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.6
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• pp.511-514
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• 2004

Punch and die plate which are press die parts can be made using machine tool or using both machine tool and W-EDM. When machine tool is used, the die life is 2,000,000 to 230,000 strokes. But with W-EDM, the die life is 700,00 to 800,000 strokes. This can be caused by the process deformation layer after W-EDM. SEM pictures of processed section before and after W-EDM are taken to see if the process deformation layer appeared. Also the elimination method is studied.