• Journal of the Korean Mathematical Society
• /
• v.32 no.3
• /
• pp.471-482
• /
• 1995

A complex n-dimensional Kaehlerian manifold of constant holomorphic sectional curvature c is called a comples space form, which is denoted by $M_n(c)$. A complete and simply connected complex space form consists of a complex projective space $P_nC$, a complex Euclidean space $C^n$ or a complex hyperbolic space $H_nC$, according as c > 0, c = 0 or c < 0. The induced almost contact metric structure of a real hypersurface M of $M_n(c)$ is denoted by $(\phi, \zeta, \eta, g)$.

• Journal of Sensor Science and Technology
• /
• v.27 no.1
• /
• pp.40-46
• /
• 2018

In this paper, we focus on optimization of a boron ($^{11}B$)-implanted n type Si epi substrate for obtaining near-zero temperature coefficient of resistance (TCR) at temperature range from 25 to $125^{\circ}C$. The $^{11}B$-implantation on the N type-Si epi substrate formed isolation from the rest of the N-type Si by the depletion region of a PN junction. The TCR increased as the temperature of rapid thermal anneal (RTA) was increased at the temperature range from $900^{\circ}C$ to $1000^{\circ}C$ for the $p^+$ contact with implantation at dose of $1E16/cm^2$, but sheet resistance of this film was decreased. After the optimization of anneal process condition, the TCR of $1126.7{\pm}30.3$ (ppm/K) was obtained for the $p^-$ resistor-COB package chips contained $p^+$ contact with the implantation of $5E14/cm^2$. This shows the potential of the $^{11}B$-implanted n type Si epi substrate as a resistor for pressure sensor in thermal stable environment applications..

• Proceedings of the KIPE Conference
• /
• 2002.11a
• /
• pp.103-107
• /
• 2002

A contact-less power supply system (CPS) allows electrical energy to supply to mobile consumers without any electrical or mechanical contact. CPS works in the same principle as a transformer, with the track litz cable forming the primary circuit and the pickup as the secondary. The track power supply generates the high frequency alternating current in the track cable. The captured AC magnetic field generated by the track conductors produces electrical energy in the pickup coil and the pickup rectifier converts the high frequency AC power to DC while regulating the power to the load. This paper presents the theoretical analysis, simulation and experiment리 results of the series-parallel resonant converter working as contact-less power supply system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.97-98
• /
• 2008

n-ZnO/p-Si heterostructure is a good candidate for ZnO-based heterojunction light emitting diodes(LED) because of its competitive price and lower driving voltage. However, the conventional LED shows much lower extraction efficiency, because it has small top contact and large backside contact. In this structure, the injected current from the top contact enters the active region underneath the top contact. Thus, the emitted light is hindered by the opaque top contact. This problem can be solved by using a current-blocking layer(CBL) that prevents the current injection into the active region below the top contact.

• International Commerce and Information Review
• /
• v.4 no.2
• /
• pp.27-46
• /
• 2002

Nowadays, the explosive evolvement of Internet. which is referred to as EC, has been prevailing. That has given the chance all of the world consumers to contact all of the world companies to enter into business relationship. But, electronic commerce laws have been established per conventional jurisdiction. some legal issues take place in the field of cross-border electronic commerce, including the governing law and competent courts. In this situations, it is gradually and widely required to lay down the internationally harmonized electronic commerce legal framework. Now, there are a lot of legal issues assumed in EC, in this study, we studied three precedence problems concerning B2C: Consumer Protection Law regarding B2C, Personal Information Protection Law in Private Sector regarding B2C, Web Site Trust Mark System.

• Journal of Korea Port Economic Association
• /
• v.28 no.3
• /
• pp.127-150
• /
• 2012

A survey showed that the public perception of the shipping industry's overall image and economic role was relatively positive. The survey revealed that public perception was mixed with respect to the multifaceted role of the shipping industry. Based on the results of this survey, this paper proposes three approaches to improving the public perception of the shipping industry. The organization contact approach includes establishing shipping institutes for city people, holding various events targeted at the public, establishing a shipping memorial hall, developing a shipping-related culture and tourism, reinventing the image of the shipping industry through a shipping-culture movement, and creating new views of the shipping industry by conducting formal education. The goods and services contact approach includes building a brand image for shipping services, providing B2C services, utilizing the national image for the shipping industry, and participating in international cooperation projects. The text contact approach includes B2B advertising, advertisements focused on the national economic and multifaceted role of the shipping industry, package advertisements for the shipping industry and related industries, the Internet and high-technology media, government-initiated PR activities regarding the multifaceted role of the shipping industry, and funding for advertising the shipping industry.

• Korean Journal of Materials Research
• /
• v.15 no.1
• /
• pp.61-65
• /
• 2005

The titanium $diboride(TiB_2)$ has high strength(750MPa), high melting point $(3225^{\circ}C)\;and\;10\%$ IACS electrical conductivity. On this account, the dispersion hardening $Cu-TiB_2$ composites(MMCs) are a promising candidate for applications as electrical contact materials. MMCs for electrical contact materials can reduce material cost and resource consumption caused by wear, due to its good mechanical and electrical property. In this study, we attempt to prepare MMCs with various volume fraction and particle size of $TiB_2$ by means of hot extruded and cold drawn process. Dry sliding wear tests were performed on a pin-on-disk type wear tester, sliding against SM45C under the different applied loads. After wear testing, the microstructures of the worn surfaces were observed by SEM and the microhardnesses of the subsurface zone were measured.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.291-296
• /
• 2000

Usually the contact between fin collar and tube surface for fin-tube heat exchanger is secured by mechanical expansion of the tubes. The objective of the present study is to develop a method of measuring the thermal contact resistance between fin collar and tube surface for fin-tube heat exchanger. Also an experimental work has been performed to evaluate the thermal contact resistance, and a rigorous numerical analysis has been employed to calculate the contact resistance from the measured data. The experiments have been conducted fur the fin-tube heat exchangers with the tube of outer diameters 7 and 9.52 mm.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.100-100
• /
• 2010

Hydrophilic $TiO_2$ films were deposited on slide glasses using titanium tetraisopropoxide (TTIP) as a precursor by metal-organic chemical vapor deposition (MOCVD). The temperature of substrate was $400^{\circ}C$ and the temperatures of precursor were kept at $75^{\circ}C$ (sample A) and $60^{\circ}C$ (sample B) during the $TiO_2$ film growth. The deposited $TiO_2$ films were characterized by contact angle measurement and uv/vis spectroscopy. The result show that sample B has very low contact angle of almost zero due to superhydrophilic $TiO_2$ surface and transmittance is $76.85%{\pm}1.47%$ at the range of 400 - 700 nm. So, this condition is very optimal for hydrophilic $TiO_2$ film deposition. However, when the temperature of precursor is lower is lower than $50^{\circ}C$ or higher than $75^{\circ}C$, $TiO_2$ could not be deposited on the substrate and cloudy $TiO_2$ film was formed due to low precursor temperature and the increase of surface roughness, respectively.

• Journal of Astronomy and Space Sciences
• /
• v.14 no.1
• /
• pp.158-165
• /
• 1997

The Sun interference event predictions for the KOMPSAT TT&C station were performed to analyze the frequency of the event and the impact on the TT&C link. The KOMPSAT orbit was propagated including only J2 geopotential term for maintaining the Sun-synchronism and no other perturbations were included. Local time of ascending node of the KOMPSAT satellite was set to 10h50m00s. The TT&C station was assumed to locate in Taejon and have 9 meter antenna for S-band link. One year of simulation from 1999/07/01 were performed out of 3 year of mission lifetime of KOMPSAT satellite. Total four times of Sun interference events were occurred during 1 year of simulation and those lasted about 50 seconds altogether. The C/N degradation of the TT&C system was calculated about 4dB. The Sun interference event of 50 seconds of year are 0.0076 percents of the S-band contact time when the 30 minute of contact time is assumed in a day.