• Korean Journal of Acupuncture
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• v.28 no.2
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• pp.37-47
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• 2011

Objectives : We have studied the effects of GaAlAs (808 nm) low level laser therapy (LLLT) and acupuncture at BL40 on neuropathic pain in rats induced by lumbar spinal nerve 5 ligation. Methods : To produce the model of neuropathic pain, under isoflurane 2.5% anesthesia, the lumbar spinal nerve 5 was ligated by 6-0 silk thread. After neuropathic surgery, we examined if the animals exhibited the behavioral sign of allodynia. The allodynia was assessed by stimulating the medial malleolus with von Frey filament and acetone. Three weeks after the neuropathic surgery, GaAlAs (808 nm) low level laser and acupuncture was inserted at BL40 once a day for 6 days. We examined the withdrawal response of neuropathic rats' legs by von Frey filament and acetone stimulation. And also the author examined c-Fos, nociceptin and nociceptin receptor in the midbrain central gray of neuropathic rats. Results : The GaAlAs (808 nm) low level laser therapy and acupuncture at BL40 decreased the withdrawal response of mechanical allodynia that assessed with von Frey filament in LLLT group on 5 and 6 times and with acetone in AT group and LLLT on 6times. The LLLT and acupuncture at BL40 decreased the c-Fos protein expression in AT and LLLT groups. The 808 nm LLLT and acupuncture at BL40 decreased the nociceptin protein and nociceptin receptor protein in LLLT group. Conclusions : We have noticed that GaAlAs (808 nm) LLLT and acupuncture at BL40 decreased mechanical allodynia in the model of neuropathic pain. c-Fos, nociceptin and nociceptin receptor expression in the central gray of that group was also decreased. This study can be used as a basic resource on a study and a treatment of pain.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.210-213
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• 1989

An early phase of the OMVPE and LACVD studies of growing AlGaAs/GaAs films is reported. The AlGaAs/GaAs epitaxy to the level of obtaining MOW structures is a crucial step for the fabrication of the devices such as SEED and/or DOES which are basic parts of the OEIC. The analysis of the OMVPE system is shown for this purpose and the basic results of the LACVD are also presented.

• Physical Therapy Korea
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• v.5 no.2
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• pp.1-14
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• 1998

This study was conducted to examine the increasing effects of Ga-As-Al laser Koryo-hand acupuncture on experimental pressure threshold. Forty healthy subjects (female=20. male=20) aged 21 to 30 years were randomly assigned to two treatment groups with same ratio in sex. The subjects in the experimental group (n=20) received Ga-As-Al laser stimulation, and those in the control group (n=20) received sham stimulation on appropriate Koryo-hand acupuncture points M10 on the left hand which is reflex point of upper trapezius portion. Experimental pressure threshold at the contralateral upper trapezius was determined with a pressure algometer and Galvanic Skin Response (GSR) before and after treatment. The change of pressure threshold between pretreatment and posttreatment in the experimental group was greater than that in the control group (p<0.05). The result indicates that Ga-As-Al laser Koryo-hand acupuncture increases experimental pressure threshold and suggests that it is an effective noninvasive pain management technique.

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.309-312
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• 2004

Two-dimensionally arrayed nanocolumn lattices were fabricated by using double-exposure laser holographic method. The hexagonal lattice was formed by rotating the sample with 60 degree while the square lattice by 90 degree before the second laser-exposure. The size and period of nanocolumns could be controlled accurately from 125 to 145 nm in diameter and 220 to 290 nm in period for square lattice by changing the incident angle of laser beam. The reactive ion etching for a typical time of 30 min using CH$_4$/H$_2$ plasma enhanced the aspect-ratio by more than 1.5 with a slight increase of the bottom width of columns.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.100-105
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• 1994

We have reduced the oscillating linewidth of the commercial single mode InGaAsP visible laser diodes which emits in the 657 nm region of the spectrum down to 10 MHz by making a extended cavity employing the Littrow-type grating. The wavelength tuning characteristics of the commercial visible laser diode (CQL820D, Philips Co.) for the grating angle, laser temperature, and injection currents were measured by using the wavemeter. The proportional coefficients of the laser were found to be 1 THzlmrad, 32.4 GHz/K, and 6.14 GHz/mA, respectively.tively.

• Laser Solutions
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• v.8 no.3
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• pp.5-10
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• 2005

[ $InxGa_{1-x}P/GaAs$ ] structures were grown by chemical beam epitaxy(CBE), Pure phosphine($PH_3$) gases were used as group V sources. for the group III sources, TEGa, TmIn were used. $InxGa_{1-x}P$ epilayer was grown on SI-GaAs substrate and has a 1-${\mu}m$ thick. We have investigated the characteristics of $InxGa_{1-x}P$ by the photoreflectance(PR) spectroscopy, The PR spectrum of $InxGa_{1-x}P$ shows third-derivative feature whose Peaks Provide energy gap. The energy gap of $InxGa_{1-x}P$ has deduced composition x. From temperature dependance of PR spectra, temperature coefficient is $dEg/dT=-3.773{\times}10^{-4}$ eV/K, and Varshni coefficients $\alpha$ and $\beta$ values obtained $4{\times}10^4$ eV/K and 267 K respectively. Also, interaction $\alpha$B was 19.4 meV using the Bose-Einstein temperature relation, and $\Theta$ value related the average phonon frequency were 101.4 K. In particular, shoulder peak related to defects observed in PR signal that measured in temperature 82 K.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.213-216
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• 2007

LGP (light guide plate) of LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of the major components which affects the product quality of LCD. In the present study, the optical patterns of LGP(2.2") are manufactured by three different methods, namely, laser ablation, chemical etching and LiGA - reflow, respectively. The pattern surface images and roughness of mold and product were compared to check the optical characteristics. From the results of measurement the optical patterns fabricated by LiGA - reflow method showed the best geometric structure as intended in design and the lowest roughness among those.

• Laser Solutions
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• v.7 no.3
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• pp.47-50
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• 2004

In this research, we investigated the characteristic of $ZnS_{0.24}Se_{0.76}/GaAs$ heterostructure by using photoreflectance sprctroscopy(PR). The oscillations observed above the 1.43 eV range were attributed Franze-Keldysh effect. The interface electric filed of $GaAs/ZnS_{0.24}Se_{0.76}\;is\;2.153{\times}104\;V/cm$.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.545-558
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• 2000

The present study was designed to investigate the effect of low power GaAsAl laser on Fos expression in the spinal cord induced by noxious mechanical stimulation. Noxious mechanical stimulation was applied to the right hind paw following 30min of low power laser treatment using different intensity and treatment point and the resulting Fos expression in the spinal cord dorsal horn was compared to that obtained in rats exposed only to the noxious mechanical stimulation. The results were summarized as follows: 1. In intact control rats, only a few Fos like immunoreactive(Fos-IR) neurons were evident in the lumbar spinal cord dorsal horn. Similarly, following prolonged inhalation anesthesia, Fos-IR neurons were absent in the dorsal horn of the lumbar spinal cord. In animals treated with noxious mechanical stimulation, neurons with nuclei exhibiting Fos immunostaining were distributied mainly in the medial half of ipsilateral laminae I-V at lumbar segments L3-5. These findings directly indicated that prolonged anesthesia used in this study did not affect the Fos expression in the spinal cord dorsal horn of intact animals and noxious mechanical stimulation treated animals. 2. In acupoint treated animals, 10mW of laser stimulation, not 3mW intensity, significantly reduced the number of Fos immunoreactive neurons in the spinal dorsal horn induced by noxious mechanical stimulation(P<.01). However, the supressive effect of low power laser stimulatin was not observed in 3m Wand 10m W of laser stimulation into non-acupoint. These data indicate that 10mW of low power laser stimulation into acupoint is capable of inhibiting the expression of Fos in the dorsal horn induced by noxious mechanical stimulation. In conclusion, these findings raise the possibility that low power laser stimulation into acupoint may be a promising alternative medicine therapy for the mechanical stimulation induced pain in the clinical field.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.11
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• pp.29-34
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• 1995

Mirror coating is applied to laser facets to improve properties of edge emitting laser diodes. In this experiment, InGaAsP/GaAs high power laser diodes were studied with respect to different degrees of anti-reflective coating. Sputterred $Al_{2}$O$_{3}$ was used as the coating material and the HR coating was kept constant at 90%. Threshold current density, differential quantum efficiency, emission wavelength and the operating current at 500mW were measured for a range of AR coating and compared with theoretically calculated values; that showed good agreements. Precise wavelength control is important for laser diodes for solid state pumping because of small absorption bandwidth. In addition, since these lasers operate under CW condition, a lowest possible operating current for a given power is desired in order to minimize the heat produced. From the results of this experiment, we were able to obtain a optimum range of AR coatings for minimum operating current. The wavelength can be varied up to 4nm within this range.