• Tunnel and Underground Space
• /
• v.17 no.3 s.68
• /
• pp.225-233
• /
• 2007

Because of Norwegian topography as valleys and fjords, a large number of tunnels has been built and 59 of them have been excavated by TBM for last 30 years. Prognosis technology has been developed and improved through lots of TBM experiences, and the NTNU prediction model has been completed. This paper focuses the improvement of net penetration rate and advance rate in 14 Norwegian and 4 Koran TBM tunnelling sites of which data were reported. Through this period, net penetration rate as well as advance rate were increased to double with the improvement of disc cutter size and cutter arrangement in Norway. These rates in Korea were also increased for 15 years even though the rates were lower compared to Norwegian. It is estimated that these low rates were mainly caused by using disc cutters less than 17 inch diameter. It is expected that net penetration rate and advance rate can be increased by improvement of machine and tunnelling technology, especially by using 17 or 19 inch of the disc cutter size in the Korean full face mechanical tunnelling site.

• The Plant Pathology Journal
• /
• v.17 no.6
• /
• pp.385.3-385
• /
• 2001

• Progress in Superconductivity
• /
• v.14 no.2
• /
• pp.82-86
• /
• 2012

A sensitive eight-channel high-Tc Superconducting Interference Device (SQUID) detection system for magnetic contaminant in a lithium ion battery anode was developed. Finding ultra-small metallic foreign matter is an important issue for a manufacturer because metallic contaminants carry the risk of an internal short. When contamination occurs, the manufacturer of the product suffers a great loss from recalling the tainted product. Metallic particles with outer dimensions smaller than 100 microns cannot be detected using a conventional X-ray imaging system. Therefore, a highly sensitive detection system for small foreign matter is required. We have already developed a detection system based on a single-channel SQUID gradiometer and horizontal magnetization. For practical use, the detection width of the system should be increased to at least 65 mm by employing multiple sensors. In this paper, we present an 8-ch high-Tc SQUID roll-to-roll system for inspecting a lithium-ion battery anode with a width of 65 mm. A special microscopic type of a cryostat was developed upon which eight SQUID gradiometers were mounted. As a result, small iron particles of 35 microns on a real lithium-ion battery anode with a width of 70 mm were successfully detected. This system is practical for the detection of contaminants in a lithium ion battery anode sheet.

• Aerospace Engineering and Technology
• /
• v.4 no.1
• /
• pp.260-267
• /
• 2005

An electronic spark ignition unit has been developed for gasoline for small UAV. The unit is programmable to adjust the optimal ignition advance angle in accordance with rpm and intake pressure. Initial advance angle and the position of Hall sensor on the engine can be set from PC via serial interface. The results are expected to be valuable core technology of powerplants in developing small UAV's.

• International Journal of Precision Engineering and Manufacturing
• /
• v.1 no.1
• /
• pp.56-61
• /
• 2000

We present a fast inspection method of machine vision for in-line quality assurance of liquid crystal displays(LCD) and plasma display panels(PDP). The method incorporates an optical spatial filter in the Fourier plane of the imaging optics to block the normal periodic pattern, extracting only defects real time without relying on intensive software image process. Special emphasis is on designing a collimated white light source to provide high degree of spatial coherence for effective real time Fourier transform. At the same time, a low level of temporal coherence is attained to improve defect detection capabilities by avoiding undesirable coherent noises. Experimental results show that the proposed inspection method offers a detection accuracy of 15% tolerance, which is sufficient for industrial applications.

• International Journal of Aeronautical and Space Sciences
• /
• v.8 no.1
• /
• pp.115-121
• /
• 2007

The aeroelastic analysis of rotor blades with trailing edge flaps, focused on reducing vibration while minimizing control effort, are investigated using large deflection-type beam theory in forward flight. The rotor blade aerodynamic forces are calculated using two-dimensional quasi-steady strip theory. For the analysis of forward flight, the nonlinear periodic blade steady response is obtained by integrating the full finite element equation in time through a coupled trim procedure with a vehicle trim. The objective function, which includes vibratory hub loads and active flap control inputs, is minimized by an optimal control process. Numerical simulations are performed for the steady-state forward flight of various advance ratios. Also, numerical results of the steady blade and flap deflections, and the vibratory hub loads are presented for various advance ratios and are compared with the previously published analysis results obtained from modal analysis based on a moderate deflection-type beam theory.

• KDI Journal of Economic Policy
• /
• v.37 no.2
• /
• pp.1-21
• /
• 2015

The creation of S&T knowledge and development of S&T- based innovation has spread worldwide from traditionally advanced countries to traditionally developing countries, often under the direction of governments. Korea is an exemplar in this new locus. Korea's burst in Science and Technology during the last three decades has made Korea a substantive player in the global production of S&T knowledge and its application to business. Although Korea still trails the US and other top countries in the quality of research, it has leaped from its 1980s standing as bit player in the knowledge economy to being among the leaders in the early 21st Century. This paper shows that Korea's advance benefited from its active participation in the global market in higher education, in international research collaborations, and its close ties to the U.S. Korea's experience offers lessons for other countries who seek to advance by becoming knowledge economies. Korea proves that a developing country can gain comparative advantage in knowledge production and use; that government policy can stimulate such a development; and that openness to the world of higher education and research is the best way to move forward and overcome the middle income trap.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.6
• /
• pp.386-394
• /
• 2001

Carboxylic acids are examples of compounds with wide industrial applications and high potential, This article presents the principles of reactive extraction along with the character-istics of tertiary amine extractants, while is given on considering the effect of the amine class and chain length, As such a brief overview the current research on reactive extraction, including the recovery of citric acid, selective amine-based extraction , and extractive fermentation is given. When discussing extractive fermentation strategies for reducing solvent toxicity are also suggested based on specific examples. Finally, solvent regeneration and stripping of extracted acid explained.

• Bulletin of the Korean Chemical Society
• /
• v.8 no.4
• /
• pp.272-275
• /
• 1987

Two polyacetylene compounds having diyn-ene chromophore were isolated from fresh Korean ginseng roots through solvent fractionation, partition and silica gel column chromatography. The low pressure semi-preparative liquid chromatography and high performance preparative liquid chromatography were used for final separation of polyacetylenic fractions. The chemical structures of these polyacetylenes were determined to be heptadeca-1,8-dien-4,6-diyn-3,10-diol and heptadeca-1,4-dien-6,8-diyn-3,10-diol by UV, FT-IR, $^1H\;NMR,\;^{13}C\;NMR,$ mass spectra and elemental analysis.

• International conference on construction engineering and project management
• /
• 2017.10a
• /
• pp.328-331
• /
• 2017

The purpose of this study is to derive construction-phase risk factors in SMEs' advance into overseas plant construction projects. For this, construction-phase risk factors were investigated on the basis of the analysis of Korean construction companies, overseas plant industry-related research institutes, and overseas data. In addition, major risk factors were derived from the investigated construction-phase risk factors, and quantitative risk factors and qualitative risk factors were analyzed and derived from these major risk factors, by the use of three rounds of the Delphi analysis.