• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.639-646
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• 2012

To analyzed the shape of Yellow Dots which appeared on the paper printed HP color laser printer, and analyzed the characteristic of Yellow Dots according to time, month, year and same printers. As a result, documents that printed in same printers had an identical Yellow Dots's shapes according to time, month, year. It was presupposed that was not embedded time and date information in HP Color LaserJet printers against Xerox, and printers which have different serial number had similar shapes but it was not identical Yellow Dots. Finally, it was found to be identical patterns in Yellow Dots of HP Color LaserJet printers used analysis. Depending on the results, it could understand HP's pattern. In the future, it will decipher patterns of Yellow Dots which have other informations to include other printer manufacturer.

• Korean Journal of Optics and Photonics
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• v.21 no.3
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• pp.123-128
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• 2010

Sum frequency generation was utilized to obtain a yellow laser with the wavelength of 578.4 nm for a probe laser of an Yb lattice clock. The output of an Nd:YAG laser with wavelength of 1319 nm and that of an Yb-fiber laser with wavelength of 1030 nm were passed through a waveguided periodically-poled lithium niobate (WG-PPLN) for sum frequency generation. It is required that the probe laser has a linewidth of the order of 1 Hz to fully resolve the Yb lattice clock transition. Thus, the linewidth of the probe laser was reduced by stabilizing the frequency to a super-cavity. This was made of ULE with a low thermal expansion coefficient, and was mounted on an active vibration-isolation table at the optimal point for the reduced sensitivity to vibration. Also, this was installed in a vacuum chamber, and the temperature was stabilized to 1 mK level. This system was installed in an acoustic enclosure to block acoustic noise. The finesse of the super-cavity was measured to be 380 000 from the photon life time of the cavity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.3
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• pp.939-941
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• 2004

Phototherapy have perpetual history, we can see an instance of it in Yellow Emperor's Conon of Medicine(黃帝內經) and Laser therapy is a field of Phototherapy being used frequently in the latest time. We treated patients with telangiectasia by laser therapy and experimented it's efficacy and studied the means of clinical application in Korean medicine. We report the capabilities of application of laser therapy, based on Korean medical theories by using resemblance between laser therapy with kyung-rak(經絡) control technique in the line that connects with the past.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.280-283
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• 2003

In this paper, there was finding laser beam focal length using the camera at the work with laser preprocess. A process have some similarity that the laser direct writing was condition of unused other light source in order to a partical object of working substrate, so we worked finding focal length using yellow light. As we found focal lengths from three points of substrate edges, The focal length of all substrates was able to be computed by calculating a plane equation using these three point. Also we make a device and software that can automatically perform all of the processes.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.1
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• pp.172-176
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• 2004

Phototherapy has perpetual history. we can see an instance of it in Yellow Emperor's Canon of Medicine(黃帝內徑) and Laser therapy is a field of Phototherapy being used frequently in the latest time. We treated patients with hyperpigmentation by laser therapy and experimented it's efficacy and studied the means of clinical application in Korean medicine. We report the capabilities of application of laser therapy, based on the Korean medical theories by using resemblance between laser therapy with kyung-rak(經絡) control technique in the line that connects with the past.

• Korean Journal of Optics and Photonics
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• v.1 no.1
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• pp.28-32
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• 1990

We have constructed and operated a discharge heated copper vapor laser which generated green (510.6 nm) and yellow (578.2 nm) light. The plasma tube was made of high purity (99.8%) alumina tube which has an inner diameter 25 mm and a length 106 cm. The electrodes, made of molybdenum sheet, were separated 108 cm apart. The laser gave an average power of 10 W at repetition rate of 5 kHz, charging voltage of 10 kV, Ne buffer gas pressure of 40 mbar, and the laser tube temperature of $1500^{\circ}C$..

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.149-150
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• 2009

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.415-419
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• 2010

A phosphor-conversion white light source is demonstrated using an InGaN-based blue laser diode (LD) and a yellow-emitting phosphor excited by the blue LD. The photometric and colorimetric properties of this blue-LD-based white light source are characterized. When injection current of the LD is 100 mA, luminous flux and luminous efficiency of the white light are found to be over 5 lm and 10 lm/W, respectively. When injection current is >90 mA, luminance is estimated to be larger than 10 Mcd/$cm^2$. In addition, color characteristics of the white light such as chromaticity coordinates, a correlated color temperature, and a color rendering index are found to be quite stable as current and temperature of the LD varies. The demonstrated LD-based white light source is expected to be used in high-brightness illumination applications with good color stability.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.309-310
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• 1998

Visual observation and subjective assessments lack the objective evaluation of laser therapy effects of the epidermal pigmented lesions. In this study, we proposed the two methods; One is CIE(Commission International d'Eclairage) $L^*,\;a^*,\;b^*$ coordinate system($L^*$ : brightness, $a^*$ : red(+) $\sim$green(-) content, $b^*$ : yellow(+) $\sim$blue(-) content), and the other is the relative color difference measurement. And we applied these two methods for quantitative evaluation of the laser therapy effects.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.189-195
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• 2003

The objective of this study is to improve the optical sensitivity of laser fluorescence for detection of incipient enamel caries. An incipient carious lesion was formed in various stages by placing an enamel specimen of a bovine tooth in STPP demineralization solution. After measuring the optical density of the lesion surface by laser fluorescence induced by argon laser and various alter of yellow(500-520nm), amber(520-540nm), orange(540-560nm), and red(560-580nm), the specimen was cut vertically to measure the depth of the lesion using a polarizing microscope. SAS statistical program was used to analyze the relationship between the optical density of the lesion suface and the depth of the lesion. The results were as follows: 1. The optical density of early carious lesion, measured by laser fluorescence with amber and orange filter, and lesion depth observed by polarizing microscope, were increased as demineralization time increased. 2. The correlation coefficient between optical density of the lesion surface and the histological depth of the lesion was the highest in orange filter(r=0.49), followed by amber(r=0.32), yellow(r=0.13) and red(0.01). 3. Regression analysis showed that the most linear relationship between the optical density and the lesion depth was existed in orange filter group. In regard above results, laser fluorescence could be considered to be reliable for optical diagnosis of dental caries.