• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.04a
• /
• pp.173-179
• /
• 1998

The processing conditions for the synthesis of platelet WS$_2$ lubricant powder through the solid-gas reaction were optimized. The tungsten and sulfur powders were sealed in a vacuum of 10$^{-6}$ torr, prior to heat-treating at 850$\circ$C for 8 days. The react~on product showed the well-developed platelet WS$_2$ powder with an average size of 3.8 $\mu$m. The synthesized WS$_2$ powder was coated on the commercial deep grooved ball bearing (No. 6203) to examine the effects of WS$_2$ coating layer on the noise and endurance of the ball bearing. The level of noise obtained from WS$_2$ coated-ball bearing was higher (56 dB) than the value occurred in the case of greece (37 dB). The life-time of the ball-bearing assembled after coating WS$_2$ powder increased 50 times compared to the non-coated bali-bearing.

• Journal of Technology Innovation
• /
• v.11 no.2
• /
• pp.151-173
• /
• 2003

This paper analyses the efficiency and productivity of R&D system across time (1991${\sim}$2000) and 16 OECD countries using multi-output and multi-input non-parametric frontier methods such as DEA (data envelopement analysis) and Malmquist productivity indexes. Malmquist productivity indexes are decomposed into two components measures, namely technical change and efficiency change. To calculate R&D efficiency and productivity, we used R&D stock and the number or researchers as R&D input proxies and the number of adjusted SCI papers and U.S. patent applications as R&D output proxies. Empirical result shows that Switzerland, Canada, U.S., Australia's R&D efficiencies are the highest and Korea's R&D productivity growth is the highest in the sample for the period. Technical efficiency growth was a more important source of productivity growth than technological innovation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.169-173
• /
• 1998

The practice of the construction and management of the underground petroleum storage facilities in Korea was investigated extensively, and the problems were identified. The advanced technologies in the U.S.A was comparatively studied. Considering the effectiveness of leak prevention and technology applicability, the following measures were suggested. To prevent corrosion of the tank, a clad tank, an interior-lining tank, or a double-wall tank was appropriate and appeared to be most cost effective. For piping, non-metalic material was suggested. To prevent spill, a catchment basin can be effective. For monitoring of leak, construction of more than one of one or combination of an automatic leak-detection device, a vapor-detection system, a ground water-monitoring system, and a double-wall detection system was recommended.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.05a
• /
• pp.173-177
• /
• 2000

In this paper new automatic gate system(AC5) which is used fo. non-stop gate entrance of container trucks is developed. The gate entrance imformations are transmitted and received by 5.8GHa dedicated short range communication(DSRC) between roadside equipment(RSE) and on-board equipment(OBE). The conventional systems, such as barcode system and camera identifiation system, are needed for container vehicles to stop at the gate. Here DSRC system and AGS are considered and the AGS and convensional systems are compared.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.168-173
• /
• 2000

Flame aerosol synthesis technology refers to the formation of fine particles from gases in flame and is widely used in practical materials processing. In this paper, an experimental investigation was performed on growth of the silica particles that were generated in $H_2/O_2$ Diffusion Flame by the direct injection or TEOS using Electro-spraying method. in this flame aerosol synthesis, four main parameters or nos interaction (flame temperature, residence time or particle in flame, TEOS flow rate, applied voltage) for particle generation and growth was investigated along the axial direction above the burner. A fairly monodisperse non-aggregated particles were successfully obtained.

• Food Science and Biotechnology
• /
• v.15 no.2
• /
• pp.173-176
• /
• 2006

The effect of enzymatically hydrolyzed vital wheat gluten (EHG) on dough mixing and the baking quality of wheat flour frozen dough was examined. Three different proteases, pepsin, trypsin, and chymotrypsin, were tested individually, sequentially paired, or in combination of all three enzymes. Addition of 1% EHG produced no observable effect on the mixing properties of wheat flour dough. However, addition of 2.5% pepsin-hydrolyzed gluten decreased the mixing tolerance of the wheat flour, and 1% trypsin-hydrolyzed gluten increased the loaf volume of both frozen and non-frozen dough. This finding suggests that trypsin-hydrolyzed vital wheat gluten may serve as a baking additive in replacement for $KBrO_3$ to improve frozen dough quality.

• Steel and Composite Structures
• /
• v.29 no.2
• /
• pp.161-173
• /
• 2018

Point bending is often used for cambering and curving structural steel girders. An analytical solution, applicable in the elasto-plastic range only, that relates applied loads to the desired curve was recently developed for inducing horizontal curves using four-point bending. This solution does not account for initial residual stresses and geometric imperfections built-in hot-rolled sections. This paper presents results from a full-scale test on a hot-rolled steel section curved using four-point bending. In parallel, a numerical analysis, accounting for both initial geometric imperfections and initial residual stresses, was carried out. The models were validated against the experimental results and a good agreement for lateral offset and for strain in the elasto-plastic and post-plastic ranges was achieved. The results show that the effect of initial residual stresses on deformation and strain is minimal. Finally, residual stresses due to cold bending calculated from the numerical analysis were assessed and a revised stress value for the service load design of the curved girder is proposed.

• Korean Journal of Bronchoesophagology
• /
• v.7 no.2
• /
• pp.168-173
• /
• 2001

Background and Objectives： The introduction of highly sensitive imaging techniques has made it possible to detect many non-palpable nodules, or“incidentaloma”in the thyroid. Discovery of these lesions raises concerns about their malignancy, but the optimal strategy for managing these lesions has not been clearly established. This study was designed to evaluate the usefulness of ultrasonographic exam with new diagnostic criteria and presume the value of mass screening for thyroid cancer. Materials and Methods : Mass screening for thyroid cancer were carried out in conjunction with mass screening for breast cancer. The subjects were 630 women aged 30 years or over. Thyroid glands were examined with 10 MHz transducer ultrasonography by one radiologist. Needle aspiration biopsy were performed when suspicious of malignancy under the new diagnostic criteria. Results and Conclusion : The new ultrasonographic criteria to diagnose thyroid cancer provided useful information and ensured more accurate evaluation. 7 cases of thyroid cancer were discovered and successfully managed. It should be further demonstrated that there is sufficient value of mass screening for thyroid cancer to perform it independently despite early cancer detection.

• Journal of Ginseng Research
• /
• v.22 no.3
• /
• pp.173-180
• /
• 1998

Thrombogenesis and atherosclerosis are mainly caused by platelet aggregation, blood coagulation, and hyperlipidemia. Platelet aggrelation, activated platelet thromboplastin time (APTT) were measured as indexes of blood coagulation and lipid contents in the subjects who have taken red ginseng products (e.g. water extract, tea, drink etc.) for 4 to 5 years. The platelet aggregation in the red ginseng-taking group was significantly decreased, as compared with the non-red ginseng-intaking group, when platelets were stimulated by 100 $\mu\textrm{g}$/ml of collagen (P<0.01). The atherogenic index and the ratio of triglyceride to HDL-cholesterol in blood, the risk factors of atherosclerosis, were decreased in the subjects of ginseng group, compared with that in control group. APTT was also prolonged to greater extent in ginseng group than in control group. These results suggest that long-term intake of ginseng products may help to prevent the risks of thrombogenesis and atherosclerosis.

• Korean Journal of Optics and Photonics
• /
• v.5 no.1
• /
• pp.173-181
• /
• 1994

An experiment on the correlation of a photon pair is introduced. The results are analyzed in the framework of quantum optics. It is shown that the vacuum state of light plays an important role for the manifestation of the non local correlation. The correlation can be explained neither by classical wave optics nor by any theory based on the idea of local reality. ality.