• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.205-205
• /
• 2006

Adsorption behaviors of positively charged matrix (PAH) onto negatively charged probe (sulfate PS particle) were investigated using DLS (dynamic light scattering) and FPR (fluorescence photobleaching recovery) as view points of matrix and salt concentration. The system experienced sharp decrease of diffusion (flocculation) at dilute condition while the system underwent gradual decrease of diffusion above semi-dilute concentration. With FPR and viscometry experiments, we revealed the probe behaviors in polyelectrolyte solution were strongly affected by the coil overlap concentration (0.5 g/L PAH concentration).

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.3
• /
• pp.402-409
• /
• 2002

Experiments were performed with double-concentric diffusion flame(DDF) in order to investigate the characteristics of soot formation and temperature distributions. The flame size and shape of the DDF are similar to those of the well-known normal co-flow diffusion flame(WF), except the formation of a tiny inverse flame near the central tube exit. A laser light extinction technique was used to measure the soot volume fractions. The temperature distributions in the flame were measured by rapid insertion of a R-type thermocouple. Soot concentrations along the flame axis of the DDF were higher than those of the NDF. However, the maximum soot volume fraction of the DDF along the periphery of the flame was lower than that of the NDF. It is mainly due to the effect of nitrogen-dilution from the inner air. Measured temperature distribution explains these trends of soot concentration. The temperature along the flame axis was also higher in DDF than that of the NDF. However, the flame temperatures at the flame front of the two flames were almost same regardless of the inner flame. This phenomenon means that the inverse flame inside the DDF did not affect on the flame structure including the temperature and soot concentration, except the region around the flame axis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.481-485
• /
• 2003

To diffuse Zn at solid-state, the $SiO_2/ZnO/SiO_2$ wafers was made by PECVD and RF Spotter. Thicknesses of bottom $SiO_2$ and cap $SiO_2$ was about $500{\AA}$ and about $3500{\AA}$. First test was Diffusion temperatures were $760^{\circ}C$, $780^{\circ}C$, and $800^{\circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr and 2nd test was Diffusion temperatures were $760^{\circ}C$, $720^{\circ}C$, and $680^{\circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about $625{\sim}650\;nm$ and red color Main reason for Iv change was by diffusion temperature not diffusion time. The lower temperature was the higher Iv. We thick that these properties is because of the very high diffusion temperature.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.25 no.8
• /
• pp.959-965
• /
• 1988

Zinc diffusion characteristics and its applicabilities have been studied using an open-tube system. Thermal decomposition of arsenide(As) at gallium arsenide(GaAs) wafer surface was well inhibited by using Ga: poly-GaAs: Zn compositon as a diffusion source. Junction depth was obtained as 4.6x10**7\ulcorner exp)-1.25/kT) where activation energy of diffusion was 1.25eV. From Boltzmann-matano analysis, it could be identified that concentration dependencies of Zn diffusivity well consisted with those of kick-out model. The ideality factor of p+-n junction formed by Zn diffusion was about 1.6 and infrared light intensity was linearly varied in the range of sixty folds. It is concluded frodm these results that Zn diffuses according to kick-out model, and open-tube method is applicable to compound semiconductor devices.

• IE interfaces
• /
• v.25 no.3
• /
• pp.327-337
• /
• 2012

The development of information and communication technology affects people's life in social, cultural, and economic aspects. When this happens in public sector, it gives way more benefits than in private sector because of its high accessibility by public. Among the technological public services in Korea, call center service which provides administrative services by telephone and internet had been spotlighted as a new type of communication between people in demand and public service provider. Public call center service is expected to be continuously diffused in years due to its accessibility and convenience for public users. This study analyzes diffusion pattern of public call center service in Korea using Bass model and tries to suggest appropriate diffusion strategies. For practical cases, three most popular public call centers in Korea are analyzed in light of diffusion pattern and operating strategies. Our analyses identify that public call centers in Korea are facing continuous diffusion in two years and there exist certain strategies to efficiently expedite the diffusion.

• Journal of Auto-vehicle Safety Association
• /
• v.14 no.1
• /
• pp.32-38
• /
• 2022

In the automobile industry, lamps are frequently used as a mean to emphasize each company's brand identity. Therefore, many detailed design models have emerged in order to realize a differentiated image in preparation for competitive vehicles. Among them, the design of a multi compartment lighting image concept that realizes light divided in multiple space also being introduced by various manufacturers. In this study, in order to solve the problem of cost and weight rise that the existing multi compartment image lamp has, using TRIZ method such as functional analysis modeling and trimming. Through this process, an idea to minimize cost and weight was derived. As the idea was designed in detail, the formation of light did not go as desired, and the diffusion of light also proceeded differently than intended. In order to overcome this problem, a new concept of corrosion and diffusion structure was applied. Eventually, it overcomes various problems and successfully applied it to a real vehicle. The idea was actually reflected in the "Santa Fe" model. Later, the media focused on the lamps to which the idea was applied, and contributed to the sale of a large number of vehicles by providing consumers with a new light sensibility. During the research process, it was possible to secure a number of patents and knowledge of new design concepts.

• Korean Journal of Optics and Photonics
• /
• v.24 no.2
• /
• pp.71-76
• /
• 2013

Using fluorescence correlation spectroscopy, we analyzed the change of effective focal volume of a confocal system with light intensity. The fluorescence correlation spectroscopy system was home-built in accordance with the He-Ne laser with a wavelength of 632.8 nm, and two kinds of samples (AlexaFluor657 and Quantum dot655) suitable for the wavelength of the laser beam were used. For each sample, we analyzed and compared the correlation functions obtained while changing the intensity of the light source in a range of 1~50 ${\mu}W$. The result shows that the radius of the focal area increases linearly through the increase of particle number and diffusion time in response to an intensity change in weak light below 10 ${\mu}W$. In the higher intensity region (>10~15 ${\mu}W$), the increasing rate of particle number and diffusion time keep increasing but at a much slower rate. Through this result, it was also found that the radius increasing rate of the focal area was reduced however, the radius still increased slightly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.08a
• /
• pp.63-66
• /
• 2003

To diffuse Zn at solid-state, the $SiO-2$/ZnO/$SiO_2$ wafers was made by PECVD and RF Sputter. Thicknesses of bottom $SiO_2$ and cap $SiO_2$ was about 500 ${\AA}$ and about 3500 ${\AA}$. Diffusion temperatures were $760^{\circ}C$, $780^{\circ}C$, and $800^{circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about 625~650 nm and red color. Main reason for Iv change was by diffusion temperature not diffusion time. The lower temperature was the higher Iv. We thick that these properties is because of the very high diffusion temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.08a
• /
• pp.59-62
• /
• 2003

Our Zn diffusion into n-type $GaAs_{0.60}P_{0.40}$ used ampoule-tube method to increase IV. N-type epitaxial wafers were preferred by $H_2SO_4$-based pre-treatment. $SiO_2$ thin film was deposited by PECVD for some wafers. Diffusion times and diffusion temperatures respectability are 1, 2, 3 hr and 775, $805^{\circ}C$. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about 625~650 nm and red color. The highest IV is about 270 mcd at the diffusion condition of $775^{\circ}C$, 3h for the wafers which didn't deposit $SiO_2$ thin films. Also, the longer diffusion time is the higher IV for the wafers which deposit $SiO_2$ thin films.

• Polymer(Korea)
• /
• v.34 no.5
• /
• pp.415-423
• /
• 2010

Poly(vinyl alcohol)(PVA) with high degree of hydrolysis of above 98% was dissolved in dimethyl sulfoxide(DMSO), and the shear viscosity was measured up to $C{\simeq}0.14\;g/mL$ in the semi-dilute solution regime. Next, as probe particle, polystyrene(PS) latex was introduced into this matrix system and its delayed diffusion due to polymer concentration was investigated by means of dynamic light scattering. When the solution viscosity of PVA/DMSO was plotted against the reduced concentration $C[{\eta}]$, which is scaled by the intrinsic viscosity, the molecular weight dependence was strongly appeared at C$[{\eta}]$ >2. Some heterogeneties in polymer solution were considered as its source. Contrary, the diffusion of probe particle in the matrix solution was observed as a single mode motion at whole concentration range but its ratio of its diffusion coefficient at solution to that at solvent, D/Do did not show any molecular weight dependence at all. However, the application limit of the stretched exponential function was disclosed at C$[{\eta}]$ >2.5.