• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.4
• /
• pp.551-559
• /
• 1998

Evaporation and ignition characteristics of fuel droplet have major influences on the efficiency and performance of engine. In the present study the experiment of evaporation and self-ignition of single fuel was performed under the various ambient conditions. An individually suspended droplet of n-heptane n-hexadecane ethyl-alcohol and light oil were employed as a liquid droplet. Evaporation and ignition characteristics were measured by using the video-camera and image processing technique under the various ambient temperatures (up to 1000310 OC)and partial pressure of oxigen(up to 60%) The evaporation curve shows that the droplet life time ignition delay time decreases as the ambient temperature and partial pressure of oxigen increase, The temperature variations of droplet were also reported for various fuel and ambient temperatures. The numerical simulations were carried out to predict droplet diameter and temperature with favorable agreement.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.125.2-125.2
• /
• 2015

The evolution of oxidation states of vanadium is monitored with ambient pressure X-ray photoemission spectroscopy. As the pressure of oxygen gas and surface temperature change, the formations of various oxidation states of vanadium are observed on the surface. Under 100mTorr of the oxygen gas pressure and 523K of sample temperature, VO2 and V2O5 are formed on the surface. The temperature-dependent resistance measurement on grown sample shows a clear metal-insulator transition near 350K. In addition, the measurement of Raman spectroscopy displays the structural change from monoclinic to rutile structures across the phase transition temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.04a
• /
• pp.65-69
• /
• 2009

Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of electrodeless lamp are related to ferrite core and cold spot temperature.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.7
• /
• pp.89-95
• /
• 2014

An LED lighting which adjusted brightness according to the surround ambient implemented using PWM technology and power devices. To measure the brightness of surround ambient a CdS sensor was used. A control board for the generation of the PWM signal was made using a MCU and duty ratio was controlled according to light intensity of surround ambient of the system. To drive the LED lamps which require high-voltage and high-current power devices were used for switching the DC power supply. Measurement results show that the IGBT is excellent as only lineality but the PowerBJT is more good to consider to efficiency and cost.

• The Journal of the Korean dental association
• /
• v.51 no.1
• /
• pp.12-17
• /
• 2013

Curing methods for denial resin-based materials are limited because of the need to polymerize quickly in the oral cavity at an ambient temperature. At present, most dental restorative composites use a camphorquinone-amine complex initiation, visible light-cure, one-component systems. Clinically, it is important to try to optimize the degree of conversion of res in composites using proper manipulation and adequate light-curing techniques to ensure the best outcome.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.976-983
• /
• 2009

Ambient Information System is an expanded term from Ambient Displays that are aesthetically pleasing displays of information which sit on the periphery of a user's attention. It describes a large set of applications that publish information in a highly non-intrusive manner[4]. Recently, as importance of the media that affects human senses and individuals' experiences increases, the role of an Ambient Information System for Public is also increase. Therefore, in this paper, the emphasis is on finding a suitable form of the Ambient Information System based on some design dimensions and we sampled possible 13 design dimensions of the practical application of an Ambient Information System for Public. For verifying the validity of our findings, we installed "Follwingflow", an interactive LED illumination and carry out an experiment on the dimensions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.5
• /
• pp.441-448
• /
• 2002

The electrical properties of the GaN-based green light emitting diodes(LEDs) with the Mg-doped p-GaN layer activated in $N_2$ or $O_2$ ambient have been compared. For the $N_2$ -ambient activation the current-voltage behavior of LEDs has been found to be improved when the Mg dopants activation was performed in the higher temperature. However, for the $O_2$-ambient activation the current-voltage characteristic has been observed to be enhanced when the Mg dopants activation was carried out in the lower temperature. The minimum forward voltage at 20mA was obtained to be 4.8 V for LEDs with the p-GaN layer activated at $900^{\circ}C$ in the $N_2$ ambient and 4.5V for LEDs with the p-GaN layer treated at $700^{\circ}C$ in the $O_2$ambient, repectively. The forward voltage reduction of the LEDs treated in the $O_2$-ambient may be related to the oxygen co-doping of the p-GaN layer during the activation process. The $O_2$ -ambient activation process is useful for the enhancement of the LED performance as well as the fabrication process since this process can activate the Mg dopants in the low temperature.

• BMB Reports
• /
• v.35 no.4
• /
• pp.384-388
• /
• 2002

A method for the ratiometric pH sensing using LysoSensor DND-192 is presented in this paper. It works in the physiological pH range. It is based on the use of two fluorophores which differ significantly in their lifetimes. As the discrimination of their emissions is performed through two different frequencies, this method can allow significant overlap of the emission spectra. A simple long-pass filter, or a combination of long-and short-pass filters, was used instead of narrow-bandpass devices. Importantly, the measurements were carried out under strong ambient light. The method could be used in a wide variety of applications, such as intracellular measurements, microscopy, bioprocess monitoring, etc.

• Archives of Plastic Surgery
• /
• v.51 no.3
• /
• pp.337-341
• /
• 2024

Nipple-areolar complex (NAC) necrosis is a devastating complication in nipple-sparing mastectomies (NSMs) that significantly impacts patient's quality of life. The use of fluorescence angiography for intraoperative assessment of mastectomy skin flap perfusion in NSM has been successfully described and can be utilized to help guide surgical decision-making. Recently, a novel fluorescence-guided surgical imager was developed, OnLume Avata System (OnLume Surgical, Madison, WI), which provides intraoperative evaluation of vascular perfusion in ambient light. In this case report, we describe the use of OnLume fluorescence-guided surgery technology to help aid in clinical decision-making for two breast reconstruction cases with concern for intraoperative nipple hypoperfusion.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.4
• /
• pp.437-449
• /
• 2003

A multi-functional indoor smog chamber was designed and evaluated to investigate photochemical or water vapor reaction mechanisms of air pollutants. Various smog chamber experiments could be conducted using ambient air or purified air in this smog chamber. The smog chamber consisted of a housing, a Teflon bag, blacklights, injection ports, sampling ports, and utility facilities. The characteristics of light source, the wall losses of air pollutants, and the quality of purified air were experimentally investigated. The maximum NO$_2$ photolysis rate was 1.10 min$^{-1}$ . In a 2.5-m$^3$ Teflon bag, the wall losses of ambient $O_3$, NO, and NO$_2$ were 1.2~2.4$\times$10$^{-3}$ min$^{-1}$ , 0.7~2.0$\times$10$^{-3}$ min$^{-1}$ , and 0.4~2.0$\times$10$^{-3}$ min$^{-1}$ , respectively. The wall loss of ambient particles ranging 0.05 to 0.2 ${\mu}{\textrm}{m}$ was 1.8~5.4$\times$10$^{-3}$ min$^{-1}$ , which was slightly higher than those of ambient gaseous species. The purified air supply system provided high quality of air with NO$_{x}$ < 1 ppb, and total hydrocarbons < 5 ppb.b.