• Title/Summary/Keyword: injection seeding

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Numerical analysis on the effects of external light injection seeding in a gain-switched DFB semiconductor laser (이득 스위칭 DFB 반도체 레이저에서 외부 광 주입 효과의 수치적 분석)

  • 이명우
    • Korean Journal of Optics and Photonics
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    • v.11 no.4
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    • pp.265-270
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    • 2000
  • We investigate the effects of the power and wavelength of externally injection seeded light on timing jitter and pulse width in a gain-switched $1.55\mu\textrm{m}$ DFB semiconductor laser by numerical simulation based on the transmission line laser model. As external seeding power increases, the timing jitter decreases and the pulse width increases. The lowest timing jitter is observed when the seed wavelength is aligned with the chirped spectrum center. By external seeding, we can decrease the timing jitter up to 1/2.7 without noticeable increase in pulse width. Our simulation results reasonably well agree with our sampled experiment and the other published papers. This proves the validity of our model to analyze a system based on a semiconductor laser. laser.

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Effective Delivering Method of Umbilical Cord Blood Stem Cells in Cutaneous Wound Healing (제대혈 유래 중간엽 줄기 세포를 이용한 피부 창상 치료시 세포 투여 방법에 따른 창상치유 효과의 비교)

  • Park, Sang Eun;Han, Seung Bum;Rah, Dong Kyun;Lew, Dae Hyun
    • Archives of Plastic Surgery
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    • v.36 no.5
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    • pp.519-524
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    • 2009
  • Purpose: This study was conducted to establish the most effective method of cell therapy by comparing and analyzing the level of wound healing after various cell delivery methods. Methods: Human mesenchymal stem cells were administered using 5 different methods on full thickness skin defects which were deliberately created on the back of 4 - week old mice using a 8 mm punch. Different modes of administration, cell suspension, local injection, collagen GAG matrix seeding, fibrin, and hydrogel mix methods were used. In each experiment group, $4{\times}105$ mesenchymal stem cells were administered according to 5 deferent methods, and were not for the corresponding control group. Results: The wound healing rate was fastest in the local injection group. The wound healing rate was relatively slow in the collagen matrix group, however, the number of blood vessels or VEGF increased most in this group. Conclusion: For rapid wound healing through wound contraction, it is advantageous to administer MSC by the local injection method. For the healing process of a wide area, such as a burn, the seeding of cells to collagen matrix is thought to be effective.

Development of a Seeder Monitoring System (파종기용 파종 감시 장치 개발)

  • 김대호;김경욱
    • Journal of Biosystems Engineering
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    • v.21 no.3
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    • pp.306-314
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    • 1996
  • A seeder monitoring system was developed to solve the problems of mis-sowing and tube clogging in direct seeding machines, which have been one of the factors that reduce the performance of sowing operations. The system consisted of photo sensors, air nozzles, an air compressor, and a one-chip micro-computer based controller. The system was also equipped with the devices that perform the functions of self-checking and intermittent air injection for cleaning seed tubes. The performance of the system was tested in the laboratory and field. Using the well-cleaned rice seed, the average time for checking the mis-sowing was 1.37 seconds in the field and 1.2 seconds in the laboratory without any malfunction. Overall evaluation of the system indicated that the system can be utilized for seeding machines not only for paddies but beans and corns.

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Tunable laser source using a self-seeding FP-LD (Self-seeding FP-LD을 이용한 파장 가변 레이저 광원)

  • Kim, Jung-Min;Lee, Hyuek-Jae
    • Journal of the Institute of Convergence Signal Processing
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    • v.22 no.3
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    • pp.104-109
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    • 2021
  • In this paper, we experimentally demonstrate a self-seeding FP-LD (Fabry Perot Laser Diode) to verify the possibility of a new tunable light source that can be used in WDM-PON (Wavelength Division Multiplexing - Passive Optical Network) system. The conventional implementation of WDM-PON using a tunable light source has a disadvantage that the center wavelength of the AWG (Arrayed Waveguide Grating) device and the tunable light source must be precisely aligned. However, the proposed tunable light source has the advantage that the tunable wavelength is automatically aligned with the center wavelength of the AWG as well as simple structure. The implemented tunable light source had a tunable band of about 14 nm or more, and the maximum RIN (Relative Intensity Noise) of about -124 dB/Hz, which showed the possibility of modulating 10 Gb/s signal by an external modulator.

Effects of Several Herbicides on Control of Creeping Bentgrass in the Kentucky Bluegrass and Its Recovery (켄터키블루그래스 포장에 침입한 크리핑벤트그래스의 제초제를 이용한 방제와 회복)

  • Kim, Young-Sun;Jo, Kap-Jun;Lee, Hyo-Sun;Kang, Young-Nam;Lim, Hye-Jung;Lee, Kyu-Seong
    • Weed & Turfgrass Science
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    • v.2 no.4
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    • pp.395-401
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    • 2013
  • This study was conducted to evaluate the selective control of creeping bentgrass invaded in Kentucky bluegrass by applying several herbicides and recovery of Kentucky bluegrass by sand injection seeding method. Selective herbicides such as mecoprop, triclopyr-TEA, imazaquin, bentazone and penosulam pyrazosulfuro-ethyl and non-selective herbicides such as glyphosate, paraquat dichloride and glyphsate ammonium oxyflorfen were used. Selective suppression of creeping bentgrass in Kentucky bluegrass was evaluated by turf color, chlorophyll and visual control indexes. Control of creeping bentgrass was most effective with the double dose application of triclopyr-TEA (2 Tri-T) in the selective herbicides and the 1 / 5 dose application of glyphosate ammonium oxyflorfen (1 / 5 GAO) in the non-selective herbicides. Visual control indexes by 2 Tri-T in selective herbicides and 1 / 5 GAOin non-selective herbicides were investigated 6.0 and 7.4, respectively. Treated sites were covered completely in 50 days after seeding Kentucky bluegrass by sand injection method.

Spectral Comb Stabilization of a Mode-Locked Semiconductor Fiber Ring Laser by External Optical Injection (외부 광주입에 의한 모드 잠금된 고리형 광섬유 레이저의 스펙트럼 빗살 안정화)

  • Seo, Dong-Sun
    • Journal of IKEEE
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    • v.15 no.4
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    • pp.313-318
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    • 2011
  • The effects of external continuous wave optical injection on spectral comb of a 10 GHz harmonically mode-locked semiconductor fiber ring laser have been studied. Greater than 40 dB spectral deeps in the spectral comb and greater than 30 dB reduction of supermode beating noise are achieved by injecting coherent light with ~ 100 KHz spectral width. To examine the possibility of using a low-cost seed source, we replace the seed source by a DFB laser with ~ 10 MHz spectral width. It shows similar spectral deeps, however supermode beating noise enhancement, rather than reduction, is observed.

Effective Response of the Peritoneum Microenvironment to Peritoneal and Systemic Metastasis from Colorectal Carcinoma

  • Yu, Min;Niu, Zhi-Min;Wei, Yu-Quan
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.12
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    • pp.7289-7294
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    • 2013
  • We here document discovery of a new and simple model of tumor seeding involving the mouse peritoneum. Irradiated tumor cells administered by i.p. injection provided effective vaccination against peritoneal carcinomatosis and distal metastasis with colorectal carcinomas. In flow cytometric analysis, CD4+ and CD8+ T lymphocytes, macrophages and myeloid-derived suppressor cells (MDSCs), which are easy to obtain in the peritoneal cavity, were revealed to have significant differences between immunized and non-immunized mice and these contributed to antitumor responses. We also observed that both serum and peritoneal lavage fluid harvested from immunized mice showed the presence of CT26-specific autoantibodies. In addition, increase in level of TGF-${\beta}1$ and IL-10 in serum but a decrease of TGF-${\beta}1$ in peritoneum was found. Taken together, these findings may provide a new vaccine strategy for the prevention of peritoneal and even systemic metastasis of carcinomas through induction of an autoimmune response in the peritoneum.

Extended Injectant Mole-Fraction Imaging of Supersonic Mixing using Acetone PLIF

  • Takahashi, Hidemi;Ikegami, Shuzo;Hirota, Mitsutomo;Masuya, Goro
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.781-789
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    • 2008
  • The fluorescence ratio method for processing planar laser induced fluorescence(PLIF) data was generalized for quantitative imaging of the injectant mole-fraction in supersonic mixing flowfields. The original fluorescence ratio approach was introduced by Hartfield et al. for tests in a special closed-loop wind tunnel to eliminate the effects of thermodynamic property variations in compressible flowfields and to provide a quantitative means of mole-fraction measurement. However, they implicitly assumed that the tracer molecules were seeded at the same fraction in both main and secondary flows. In the present study, we proposed generalizing the Hartfield method by considering differences in the tracer seeding rates. We examined the generalized method in a mixing flowfield formed by sonic transverse injection into a Mach 1.8 supersonic air stream. The injectant molefraction distribution obtained from PLIF data processed by our new approach showed better agreement with the gas chromatograph than one based on the Hartfield method.

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