• Journal of Oral Medicine and Pain
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• 제19권1호
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• pp.33-43
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• 1994

The purpose of this paper was to observe the influence of Ga-As semiconductor-low power generating laser on she appearance and actions of tenascin, extracellular matrix, as healing process of intentional wound on the experimental animals is taking place. 35 rabbits were divided into control and experimental group. ; and on each, 3mm-long and 2mm-deep, surgical wounds were created on buccal oral mucosa and thoracodorsal portion of skin. Ga-As laser was applied to the experimental group starting a day of the day the wounds were created , the laser was applied for 5 minutes every other day. Tissue samples were taken after the 2, 4, 7, 10, and 14 days after wound formation. Then tile healing process of experimental and control groups were observed and compared, using light microscope. Afterwards, the samples were immunohistochemical stained and again observed tenascin by quantitative measuring. The following results were obtained : 1. Tenascin was observed prevalently on epithelial cells, border area of dermis, and interstitial matrix between connective tissue layers in both experimental and control groups. 2. In oral mucosa, the experimental group showed significant increase in the appearance of tenascin after 4 days compared to the control group, but after 10 days, it decreased to a point which is even less than the control group. 3. In the skin samples, the pattern of appearance of tenascin was the same in both groups, but there was some difference concerning when the peak period was shown, In the experimental group, the peak period of tenascin expression was the 7 days after wound formation in epithelium and connective tissue. In the control group, the peak period was 10 days after. 4. In both the experimental and control groups, tenascin first appeared in the epithelium near the wound area and submucosa, and then spread on the underlying connective tissue. In conclusion, appearance of tenascin is closely related to regeneration of epithelium and development of granulation tissue : therefore, low power laser, which fastnes appearance of tenascin, is sure to faciltate healing process of oral mucosa.

• Bulletin of the Korean Chemical Society
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• 제10권1호
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• pp.96-101
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• 1989

The infrared multiphoton decomposition of trichloroethylene-H(TCE-H) and trichloroehtylene-D(TCE-D) was studied by using the high power $CO_2$ laser. The pressure dependence of TCE-H decomposition showed that the HCl elimination channel to form ClC ≡ CCl was the major step at high pressures, while the HC ≡ CCl formation step became important at low pressures. $Cl_2C$ = CHCl ${\rightarrow}$ (high pressure) ClC ${\equiv}$ CCl + HCl ${\rightarrow}$ (low pressure) HC ${\equiv}$ CCl + 2Cl${\cdot}$($Cl_2$) The IRMPD of TCE-H and TCE-D mixtures with 10P(20) laser line showed that optimum conditions of large isotope selectivity were the low system pressures and high laser powers. The experimentally observed dependence of the branching ratios on the pressure and laser fluence, and the isotope selectivity coefficients were quantitatively explained by using the modified energy grained master equations (EGME) model.

• The Korean Journal of Pain
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• 제4권2호
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• pp.142-146
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• 1991

One hundred twenty patients with acute and chronic pain treated by a low power laser were divided into several groups by their pathology and evaluated according to their response rate to laser therapy through a follow-up study. 1) The ages of the patients were between the early twenties and late forties (71.7%), and there was no differences between sexes. 2) The spinal pathology group was the most common(52.5%) and the articular pathology group occupied next (14.2%). 3) The average duration of Laser therapy was about 20 days and response to the therapy appeared about the eighth day. 4) The response to the therapy in the spinal pathology group appeared about the eighth day and the average duration of therapy was about 18 days. 5) The response to the therapy in the articular pathology group appeared about the eighth day and the average duration of therapy was about 28 days. 6) The response rate of the spinal pathology group was 81.0%, and remarkable symptom relief was noted when compaired to a 58.7% response rate in the control group, 7) The response rate of the articular pathology group was 82.4%, which was similar to the control group. 8) The response rate of the miscellaneous group was 87.0%, and remarkable symptom relief was noted when compaired to a 66.7A response rate in the control group. 9) The mean response rate of all patients treated by a low power laser was 82.5% and that of the control group was 70.5%. Laser therary proved to be an effective treatment modality for acute and chronic pain.

• Journal of Magnetics
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• 제19권1호
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• pp.32-36
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• 2014

The purpose of this study was to investigate the effect of pulsed magnetic field (PMF) and low frequency low level laser (LFLLL) stimuli on acupoint LI4 (Hegu) using photoplethysmography (PPG). Our PMF system was designed to generate maximum intensity of 0.20 T at a transition time of 0.16 ms, with pulse intervals of 1 Hz. The diode laser with wavelength of 650 nm and power of 5 mW was also employed. It was observed the change of the pulsating blood volume through measuring PPG signals from both hands. These results imply that stimulating acupoint LI4 with PMF and LFLLL improves the circulation of peripheral vascular system. In particular, PMF stimulation brings a big improvement of the blood flow even with short term stimulation of 3-4 minutes compared to LFLLL stimulus.

• 대한기계학회논문집B
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• 제23권11호
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• pp.1379-1389
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• 1999

A new technique for control of size and shape of flame-made particles is Introduced. The characteristic sintering time can be controlled Independently of collision time by heating the particles with irradiation of laser because the sintering time strongly depends on temperature. A coflow oxy-hydrogen diffusion flame burner was used for $SiCl_4$ conversion to silica particle. Nanometer sized aggregates irradiated by a high power CW $CO_2$ laser beam were rapidly heated up to high temperatures and then were sintered to approach volume-equivalent spheres. The sphere collides much slower than the aggregate, which results in reduction of sizes of particles maintaining spherical shape. Light scattering of Ar ion laser and TEM observation using a local sampling device were used to confirm the above effects. When the $CO_2$ laser was irradiated at low position from the burner surface, particle generation due to gas absorption of laser beam occurred and thus scattering intensity increased with $CO_2$ laser power. At high irradiation position, scattering intensity decreased with $CO_2$ laser power and TEM image showed a clear mark of evaporation and recondensation of particles for high $CO_2$ laser power. When the laser was irradiated between the above two positions where small aggregates exist, average size of spherical particles obviously decreased to 58% of those without $CO_2$ laser irradiation with the spherical shape. Even for increased carrier gas flow rate by a factor of three, TEM photograph also revealed considerable reduction of particle size.

• 대한의용생체공학회:의공학회지
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• 제36권5호
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• pp.191-197
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• 2015

Laser acupuncture is defined as the stimulation of traditional acupuncture points with low-intensity, nonthermal laser irradiation. Possible advantages in using laser acupuncture are the noninvasive, painless and low risks of infection treatment. The purpose of this study is to assess the effect of laser acupuncture on the quality and waveform of arterial pulses. Ten acupuncture points were stimulated repeatedly three times in 30 individuals by laser with emission in the near infrared spectral region (808 nm) using an out power and power density of 45 mW and $143W/cm^2$. The analysis of pulse quality and waveform was performed based on the measurement of arterial pressure of the left and right wrist, using a 3-dimensional blood pressure pulse analyzer. Excess-like pulse quality of subjects before laser acupuncture changed significantly to balanced pulse quality after 10, 20, and 30 minutes of laser acupuncture; coefficient of deficient or excess, $C_{DE}$, decreased significantly from 0.68 before acupuncture to 0.61, 0.55, and 0.55 after 10, 20, 30 minutes of laser acupuncture ($$p{\leq_-}0.006$$), respectively. Other pulse qualities, floating or sinking, slow or rapid, choppy or slippery did not change significantly by laser acupuncture (p > 0.05). Pulse waveform analysis showed that amplitude of main peak (systolic function or aortic compliance, $h_1$) of left and right artery pulse waves decreased significantly after 10, 20, and 30 minutes of laser acupuncture (p < 0.05). Other parameters, duration of one cardiac cycle (T), duration of rapid systolic ejection ($T_1$), duration of the systolic phase ($T_4$), and duration of the diastolic phase ($T_5$) of left and right artery pulses did not change significantly after laser acupuncture (p > 0.05).

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.31-36
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• 2009

In this paper, the laser cutting characteristics of the flexible PCB using high power Nd:YAG UV laser were investigated. A specific FPCB model was selected for the experiment. Test sheets were made, which had equal materials and layer structure to those of the outline (OL) region and the contact pad (CP) region in the FPCB. The experiment is made up of two stages. In the first stage of the experiment, the laser cutting fluence was found, which is the threshold fluence to cut the test sheets completely. The laser cutting fluence of the OL sheet is $1781.26{\sim}1970.16\;J/cm^2$ and that of the CP sheet is $2109.34{\sim}2134.34\;J/cm^2$. In the second stage, cutting performance and its qualities were analyzed by the experiment. The laser cutting performance remained almost unchanged for all laser and process parameter sets. The average cutting width (top side/bottom side) of the OL sheet was $40.45\;{\mu}m/11.52\;{\mu}m$ and that of the CP sheet was $22.14\;{\mu}m/10.93\;{\mu}m$. However, the laser cutting qualities were different according to the parameters. The adjacent region of the cutting line on the OL sheet was carbonized as the beam speed was low and the overlap coefficient was high. The surface quality around the cutting line of the CP sheet was about the same. Carbonization and debris occurred on the surface of the cutting line. As a result of the experiment, the cutting qualities were better as the overlap coefficient was made low and beam speed high. Therefore, the overlap coefficient 2 or 3 is proper for the FPCB laser cutting.

• 마이크로전자및패키징학회지
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• 제11권3호
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• pp.71-76
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• 2004

레이저다이오드 냉각을 위해 사용되는 TEC의 소비전력을 3차원 유한요소해석으로 예측하고 실험을 통해 해석결과의 타당성을 검증하였다. 레이저다이오드의 소비전력, 제어온도, 외기온도, 열전달경로의 열저항 등이 고려되었다. 저소비전력 모듈의 설계를 위해 해석결과를 바탕으로 Pellet의 숫자와 치수로 결정되는 TEC 형태에 따른 소비전력특성을 고찰한 결과 Pellet의 숫자가 적으며 접지면적이 작고 길이가 길수록, 즉 열저항이 증가할수록 소비전력은 감소하였다.

• E2M - 전기 전자와 첨단 소재
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• 제8권5호
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• pp.558-563
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• 1995

Dynamic characteristics of TbFeCo magneto-optical recording media at 680nm wavelength region were studied by means of computer simulation of disc structure and optimization of process variables during sputter deposition. With the slightly reduced Kerr rotation angle due to the reduced wavelength of optical laser source, the improved recording density in TbFeCo magneto optical media showing the CNR greater than 50dB could be achieved by only adjusting the thickness of dielectric and the recording layers when the wavelength of light source is changed from 780nm to 680nm. In addition, the recording power margin of 5mW and the 2mW minimum recording power was realized, It was shown from the present study that the increase in laser power density demonstrated feasibility of low cost and low power laser diode with the reduced optimum recording power.

• 한국인터넷방송통신학회논문지
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• 제14권4호
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• pp.85-90
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• 2014

ZigBee를 이용한 개인영역망으로 구성된 무선 다중 통합 레이저 교전 시스템을 구현하였다. 무선 레이저 검출기는 아날로그 신호처리, 해독 및 무선통신 기능을 갖추어야하는 반면 병사의 신체에 부착될 수 있도록 저전력소모, 소형 및 경량화 되어야한다. 소형 및 경량화를 위해 해독기는 소프트웨어적으로 구현하였고, 협대역 광학 필터를 이용하여 시스템의 부하를 줄여줌으로써 저전력화를 꽤하였다. 제작된 무선 레이저 검출기는 광잡음 환경에서도 정상 작동하였다. 무선 개인영역망을 통한 PU(Player Unit)와의 통신은 무선 레이저 검출기의 부착 위치에 따라 다소 차이가 있었으나 -40.2dBm이상의 출력으로 송신할 경우 100%의 수신율을 확보할 수 있었다.