64 results on '"C Y, Cho"'
Search Results
2. Comparative Study Between Extracavity and Intracavity Frequency-Doubled Laser at 532 nm: Application for the Deep Ultraviolet Generation at 266 nm
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C. Y. Cho, C. Y. Tang, Y. P. Huang, Kuan-Wei Su, and Yung-Fu Chen
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Materials science ,business.industry ,Energy conversion efficiency ,Second-harmonic generation ,medicine.disease_cause ,Laser ,Q-switching ,Atomic and Molecular Physics, and Optics ,Semiconductor laser theory ,law.invention ,Optics ,Electricity generation ,law ,medicine ,Optoelectronics ,High harmonic generation ,Electrical and Electronic Engineering ,business ,Ultraviolet - Abstract
We construct a reliable actively Q-switched Nd:YVO4 laser to comparatively investigate the output performance of the second harmonic generation between the extracavity and intracavity configurations under a similar operated condition. It is experimentally found that the peak power at 532 nm obtained with the extracavity second harmonic generation is remarkably higher than that obtained with the intracavity configuration, even though the higher output power and larger pulse energy can be acquired with the intracavity second harmonic generation. We further perform the extracavity fourth harmonic generation to verify that the extracavity second harmonic generation is more advantageous in generating deep ultraviolet laser at 266 nm than the intracavity one, where the conversion efficiencies from 532 to 266 nm for each case are 37.1% and 7.2%, respectively. Moreover, under an incident pump power of 26 W at 808 nm and a pulse repetition rate of 40 kHz, the output power at 266 nm as high as 1.67 W is effectually generated with the combination of the extracavity second and fourth harmonic generations, corresponding to the conversion efficiency from 808 to 266 nm up to 6.4%.
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- 2015
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3. LED-side-pumped Nd:YAG laser with20% optical efficiency and the demonstration of an efficient passively Q-switched LED-pumped solid-state laser
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Kuan Wei Su, Chi Chih Pu, Yung-Fu Chen, and C. Y. Cho
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Materials science ,Active laser medium ,business.industry ,Energy conversion efficiency ,02 engineering and technology ,Laser pumping ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,law.invention ,010309 optics ,Optics ,Solid-state laser ,law ,Nd:YAG laser ,0103 physical sciences ,Diode-pumped solid-state laser ,Optoelectronics ,0210 nano-technology ,business ,Light-emitting diode - Abstract
A LED-array-pumped Nd:YAG laser with optical conversion efficiency up to 20.2% is demonstrated by direct side-pumping without a coupling lens. The 810-nm LED array with a full-width-half-maximum of 30 nm and an area fill factor of 50% is designed to attain high spectral absorption efficiency with a pump density of 151.8 W/cmsup2/sup. Furthermore, higher than 45% overall coupling efficiency is achieved by placing the LED array as close as possible to the side of the gain medium for overcoming the large pumped divergence. More importantly, by using the efficient pump scheme, the demonstration of a passively Q-switched LED-pumped laser is successfully realized with a pulsed energy of 1.42 mJ.
- Published
- 2017
4. Compact coupling scheme to achieve the synchronously dual self-mode-locked operation with a 35.2 THz optical beating
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Tzu Lin Huang, Cheng Lin Sung, C. Y. Cho, Yung-Fu Chen, Hsing Chih Liang, and Hao Ping Cheng
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Coupling ,Materials science ,Laser diode ,Terahertz radiation ,business.industry ,02 engineering and technology ,Output coupler ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,law.invention ,010309 optics ,Synchronization (alternating current) ,020210 optoelectronics & photonics ,Optics ,law ,Optical cavity ,0103 physical sciences ,Diode-pumped solid-state laser ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,business - Abstract
A synchronously dual self-mode-locked (SML) operation at 946 and 1064 nm is experimentally accomplished by using a compact coupling scheme to obtain the optical beating frequency up to 35.2 THz. The SML emissions at 946 and 1064 nm are established by a monolithic Nd:YAG cavity and a Nd:YVOsub4/subcrystal in a flat-flat cavity, respectively. Two gain media are butt adjoined to be longitudinally pumped by a single laser diode. The monolithic Nd:YAG crystal is used not only as the 946 nm laser cavity, but also as the output coupler of the Nd:YVOsub4/sub1064 nm laser. More importantly, the output surface of the monolithic Nd:YAG laser is coated to generate the optical feedback for the synchronization of the dual SML operation. At a pump power of 10.7 W, the output powers at 1064 and 946 nm can simultaneously reach 1.5 W by controlling the focal position of the pump waist.
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- 2017
5. Orthogonally polarized self-mode-locked Nd:YAG laser with tunable beat frequencies
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Cheng-Lin Sung, C. Y. Cho, Chia-Yu Lee, Hao-Ping Cheng, and Yung-Fu Chen
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Materials science ,Birefringence ,business.industry ,Physics::Optics ,Beat (acoustics) ,Laser ,01 natural sciences ,law.invention ,010309 optics ,Crystal ,Optics ,Mode-locking ,Solid-state laser ,law ,Nd:YAG laser ,0103 physical sciences ,Optoelectronics ,010306 general physics ,business - Abstract
An orthogonally polarized self-mode-locked Nd:YAG laser is demonstrated in a short linear cavity. Under an incident pump power of 8.2 W, the average output power can be measured to be 3.8 W. The beat frequency Δfc between two orthogonally polarized mode-locked components is observed and increases linearly with an increase in the incident pump power. The origin of the beat frequency is utterly confirmed to be caused by the thermal-stress-induced birefringence in the Nd:YAG crystal and is theoretically simulated. The present result provides a promising method to achieve orthogonally polarized mode-locked lasers with tunable beat frequency.
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- 2017
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6. Energy scale-up and mode-quality enhancement of the LED-pumped Nd:YAG Q-switched laser achieving a millijoule green pulse
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Chi Chih Pu, Kuan Wei Su, Yung-Fu Chen, and C. Y. Cho
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Materials science ,business.industry ,Energy conversion efficiency ,Saturable absorption ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Q-switching ,Atomic and Molecular Physics, and Optics ,law.invention ,Pulse (physics) ,010309 optics ,Wavelength ,Optics ,Quality (physics) ,law ,Optical cavity ,0103 physical sciences ,0210 nano-technology ,business ,Pulse-width modulation - Abstract
An efficient LED pumping module is explored for the demonstration of energy scaling of passively Q-switched output to millijoule high-pulse-energy level. For the free-running operation at fundamental wavelength, the highest optical conversion efficiency of 23.7% is reached. By using a Cr4+:YAG crystal as the saturable absorber, the passively Q-switched output energy is up to 14.5 mJ in a compact setup. The laser resonator is further optimized to shorten the output pulse width and to obtain better mode quality. The pulse width of the Q-switched emission is as short as 25 ns, and the peak power is up to 0.7 MW. With such a highly efficient configuration, the extracavity second-harmonic generation at 532 nm can be achieved with 4.5 mJ pulse energy.
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- 2019
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7. Development of automated pipe spool monitoring system using RFID and 3D model for plant construction project
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C. H. Kim, Soon-Wook Kwon, and C. Y. Cho
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Mechanism (engineering) ,Engineering ,Piping ,Task management ,business.industry ,Embedded system ,Radio-frequency identification ,Wireless ,Tracking system ,business ,Mobile device ,Wireless sensor network ,Civil and Structural Engineering - Abstract
For plant construction, installation of complex pipe spools is one of the integral parts of management and operation. Construction errors in such plants have been increasing as they become bigger and more complex. To reduce the number of construction errors, an efficient management mechanism for pipe spool installation with real-time monitoring is desired. A Ubiquitous Sensor Network (USN), which utilizes low-power wireless data communication technologies such as Wireless Local-Area Networking (WLAN) and RFID (Radio Frequency Identification) is seen as an enabling technology for intelligent management of piping installation. This research aims to develop a real-time pipe tracking system for plant construction, utilizing state-of-the-art technologies such as RFID and 3D digital models on a handheld mobile device, which allows more efficient task management than a conventional computer.
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- 2013
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8. Monolithic dual-polarization self-mode-locked Nd:YAG 946-nm lasers: controlling beat frequency and observation of temporal chaos
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C. L. Sung, Chi-Young Lee, Yung-Fu Chen, C. Y. Cho, T. L. Huang, and Hsin-Ming Cheng
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Materials science ,Birefringence ,business.industry ,Orthogonal polarization spectral imaging ,Chaotic ,Physics::Optics ,Second-harmonic generation ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,law.invention ,Power (physics) ,010309 optics ,Crystal ,Optics ,Dual-polarization interferometry ,law ,0103 physical sciences ,Optoelectronics ,0210 nano-technology ,business - Abstract
The self-mode-locked (SML) operation at 946 nm can be achieved with a monolithic Nd:YAG crystal when the pump power is above the threshold of the multiple-longitudinal-mode generation. The SML output is further found to include two orthogonal polarization components with a beat frequency coming from the birefringence effect in the laser crystal. The beat frequency can be widely adjusted in the range of 5−220 MHz by controlling the cooling temperature. The present experiment also confirms the theoretical prediction that the two-mode operation generally exhibits the chaotic dynamics when the frequency difference is sufficiently close to the relaxation frequency.
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- 2016
9. The energy scaling in a side-pumped ultra-low-magnification unstable resonator by employing a compact master oscillator power amplifier
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Kuan-Wei Su, Huang Yanlin, and C. Y. Cho
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Physics ,Quantum optics ,Physics and Astronomy (miscellaneous) ,Oscillation ,business.industry ,Amplifier ,General Engineering ,Physics::Optics ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,law.invention ,010309 optics ,Resonator ,Optics ,law ,0103 physical sciences ,Optical parametric oscillator ,Laser beam quality ,Laser power scaling ,0210 nano-technology ,business - Abstract
The energy scaling for a diode-side-pumped passively Q-switched Nd:YAG laser in an ultra-low-magnification unstable convex–concave resonator is investigated. Theoretical analysis and experimental results indicate the fact that the energy scaling is restricted by the increasing of side-pumping sources inside the resonator because of the significant pump-to-mode size mismatching. It is verified that employing the master oscillation power amplifier can effectively enlarge the output pulse energy and improve the beam quality. Up to 60-mJ pulse energy with 17-MW peak power is obtained at a pump energy of 520 mJ. A 1573-nm eye-safe laser emission with pulse energy up to 25 mJ is further attended via the extracavity optical parametric oscillator.
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- 2016
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10. Synchronized self-mode-locked 1061-nm and 1064-nm monolithic Nd:YAG laser at cryogenic temperatures with two orthogonally polarized emissions: generation of 670 GHz beating
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Yung-Fu Chen, C. Y. Cho, C. L. Sung, Kai-Feng Huang, T. L. Huang, Hsin-Ming Cheng, H. C. Liang, and Kuan-Wei Su
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Materials science ,Birefringence ,business.industry ,Physics::Optics ,02 engineering and technology ,Laser pumping ,Injection seeder ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,law.invention ,010309 optics ,Synchronization (alternating current) ,Optics ,Mode-locking ,law ,Nd:YAG laser ,0103 physical sciences ,Optoelectronics ,Center frequency ,0210 nano-technology ,business - Abstract
A dual-wavelength self-mode-locked monolithic Nd:YAG laser at 1061 and 1064 nm is realized at cryogenic temperatures. At an incident pump power of 5.5 W, the total output power can reach 2.5 W and the mode-locked pulse width is 29 ps at a pulse repetition rate of 7.75 GHz. The synchronization of the dual-wavelength emissions leads to a beat frequency of 670 GHz in the individual mode-locked pulse. It is further discovered that the laser output consists of two orthogonally polarized components with a central frequency difference of 127 MHz. The central frequency difference between two orthogonal polarizations mainly arises from the external mechanical stress introduced by the copper holder for the laser crystal.
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- 2016
11. Achieving dual-wavelength co-linear emission at quasi-three-level and four-level transitions with compactly combined dual gain media
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Yung-Fu Chen and C. Y. Cho
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Materials science ,business.industry ,Ti:sapphire laser ,02 engineering and technology ,Laser ,01 natural sciences ,law.invention ,Dual (category theory) ,010309 optics ,Reduction (complexity) ,Resonator ,020210 optoelectronics & photonics ,Optics ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Dual wavelength ,Absorption (electromagnetic radiation) ,business ,Quasi three level - Abstract
A dual-wavelength laser at four-level and quasi-three-level transitions is demonstrated in a linear resonator. The compactly combined Nd:YAG and Nd:YVO 4 crystals successfully improve the efficiency limitation for the dilemma between reabsorption loss and absorption reduction.
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- 2016
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12. Exploring vortex structures of circularly geometric beams from off-axis pumped solid-state lasers with an external mode converter
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Hsing Chih Liang, Yung-Fu Chen, Kai-Feng Huang, C. Y. Cho, J. C. Tung, P. H. Tuan, and Kuan-Wei Su
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Materials science ,business.industry ,Solid-state ,Plane wave ,Laser ,law.invention ,Vortex ,Optics ,Interference (communication) ,law ,Fiber laser ,Physics::Accelerator Physics ,business ,Optical vortex ,Beam (structure) - Abstract
We employ a plane wave to perform interference with the circularly geometric beam from off-axis pumped solid-state lasers. The good agreement between the experimental and calculated interference patterns indicates vortex structures of circularly geometric beams.
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- 2016
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13. Design model of thermally insensitive convex-concave cavities for high-power diode-end-pumped solid-state lasers
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Kai-Feng Huang, J. C. Tung, Chia-Yu Lee, P. H. Tuan, C. Y. Cho, Kuan-Wei Su, Yung-Fu Chen, and C. C. Chang
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Materials science ,business.industry ,Solid-state ,Regular polygon ,Physics::Optics ,Laser ,law.invention ,Optics ,Power diode ,Feature (computer vision) ,law ,Physics::Accelerator Physics ,Optoelectronics ,Laser power scaling ,Thermal lensing ,business - Abstract
The thermally insensitive feature of convex-concave cavity is confirmed that can achieve power scaling in a wide-range cavity length. The influence of cavity length on the self-mode-locking behavior in this cavity is further explored.
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- 2016
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14. Orthogonally polarized dual-wavelength cryogenic Nd:YLF laser and the investigation to the passive Q-switching
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Cheng Hao-Ping, Kai-Feng Huang, C. Y. Cho, Yung-Fu Chen, Kuan-Wei Su, and T. L. Huang
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Materials science ,business.industry ,law ,Thermal effect ,Optoelectronics ,Dual wavelength ,business ,Laser ,Q-switching ,law.invention - Abstract
A Nd:YLF laser is cryogenically cooled for the demonstration of orthogonally polarized dual-wavelength emissions at 1047 nm and 1053 nm. The approach of passively Q-switching with less thermal effect is also experimentally investigated.
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- 2016
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15. >100-kW linearly polarized pulse fiber amplifier seeded by a compact efficient passively Q-switched Nd:YVO4 Laser
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W. Z. Zhuang, Yung-Fu Chen, Y. P. Huang, Jung Y. Huang, W. C. Huang, and C. Y. Cho
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Materials science ,business.industry ,Linear polarization ,Pulse duration ,Condensed Matter Physics ,Laser ,Polarization (waves) ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,law ,Pulse wave ,Seeding ,Photonics ,business ,Instrumentation ,Bandwidth-limited pulse - Abstract
We thoroughly develop compact high-peak-power Nd:YVO4/Cr4+:YAG passively Q-switched lasers (PQS) as the seed source of the fiber amplifier. We exploit a nearly hemispherical cavity to reach the second threshold criterion and systematically consider the thermal lensing effect and the mode-size matching in the overall optimization. Employing a Cr4+:YAG absorber with 70% initial transmission, we obtain a 50-kHz seed pulse train with the pulse duration of 4.8 ns and the pulse energy of 22 μJ at a pump power of 5.4 W. Injecting this seed laser into a polarization maintained Yb-doped fiber, the pulse energy and peak power at a pump power of 16 W are enhanced up to 178 μJ and 37 kW, respectively. We also use an absorber with 40% initial transmission to generate a 25 kHz pulse train with the pulse duration of 1.6 ns and the pulse energy of 36 μJ at a pump power of 5.4 W. With this seed laser, we find that the surface damage of the fiber limits the maximum pulse energy and peak power to be 192 μJ and 120 kW, respectively.
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- 2012
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16. Microsatellite DNA markers indicate three genetic lineages in East Asian indigenous goat populations
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K. Ishii, C. Y. Cho, H. Dadi, D. Nyamsamba, Sutopo, M. Minezawa, Yukimizu Takahashi, MO Faruque, Koh Nomura, and Takashi Amano
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Genetics ,Genetic diversity ,education.field_of_study ,Goats ,Population ,Genetic Variation ,Zoology ,General Medicine ,Biology ,Southeast asian ,Pedigree ,Genetic distance ,Genetic variation ,Animals ,Microsatellite ,Animal Science and Zoology ,Genetic variability ,education ,Inbreeding ,Alleles ,Phylogeny ,Microsatellite Repeats - Abstract
The genetic differentiation and phylogenetic relationships of 18 indigenous goat populations from seven East Asian countries were analysed based on data obtained from 26 microsatellite DNA markers. The mean number of alleles (MNA) per population ranged from 2.5 to 7.6, with an average of 5.8. Genetic variability estimated from MNA and heterozygosity (H(E) and H(O) ) were relatively low in coastal and island populations. A heterozygous deficiency within populations (F(IS) = 0.054, P < 0.001) and total inbreeding (F(IT) = 0.181, P < 0.01) were observed, and genetic differentiation in the populations (F(ST) ) was 13.4%. The results of Bayesian model-based clustering and a neighbour-joining tree based on Nei's genetic distance showed that Asian goat populations could be subdivided into at least the following three genetic clusters: East Asian, Southeast Asian and Mongolian. These results are in close accordance with conventional morphological and geographical classifications and migration history.
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- 2012
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17. Exploring the power scaling of the cryogenic 946 nm monolithic laser
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C. Y. Cho, Yung-Fu Chen, Tzu Lin Huang, Hao Ping Cheng, and Kai-Feng Huang
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Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,02 engineering and technology ,Cryogenics ,Laser ,Reduction ratio ,01 natural sciences ,law.invention ,Power (physics) ,010309 optics ,Crystal ,Wavelength ,020210 optoelectronics & photonics ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Laser power scaling ,business ,Instrumentation ,Scaling - Abstract
The criterion for achieving power scaling of the cryogenically cooled monolithic 946 nm laser is investigated by varying crystal length. Theoretical analysis of the mode-to-pump size matching indicates that the optimal power can be obtained with a crystal length of 8 mm. Furthermore, the pump–wavelength dependence of the output power can be less sensitive when a longer crystal was employed. We demonstrate 946 nm monolithic lasers with various crystal lengths to verify the theoretical analysis. The highest output power (30.2 W) is obtained by using an 8 mm Nd:YAG crystal at 130 K. Moreover, the output power reduction ratio is found to be smaller than 15% with the pump wavelength fluctuating between ±1 nm.
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- 2018
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18. Association between HSP70 Genotypes and Oocytes Development on In vitro Maturation/Fertilization in Pig
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S. H. Yeon, S. R. Cho, S. S. Lee, C. Y. Cho, Z. D. Li, S. H. Choi, H. J. Jin, B. D. Sang, D. S. Son, M. S. Wee, C. K. Park, and C. D. Kim
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Human fertilization ,Pronucleus ,Capacitation ,Genotype ,Animal Science and Zoology ,Biology ,Molecular biology ,Sperm ,In vitro ,Food Science ,Hsp70 ,In vitro maturation - Abstract
This study was performed to clarify whether the variation of stress related heat shock protein 70 (HSP70) (GenBank X68213) gene was associated with the nuclear morphological change of in vitro maturation and in vitro capacitation in oocytes of pig ovaries obtained at the slaughterhouse. The nucleic acid substitution of C to G at the 483rd position was found out in HSP70 K1 (290- 512) from X68213. The ovaries were categorized into CC, CG, and GG genotypes using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) (BsiHKA I). After the second in vitro maturation of immature fresh oocytes, the relation of nuclear morphological change in oocytes with the genotype of HSP70 K1 gene was such that the MII ratios of the genotype GG and CG (46.93% and 42.20%, respectively) were significantly higher than that of the CC genotype (10.71%) (p
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- 2008
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19. Cryogenically monolithic self-Raman lasers: observation of single-longitudinal-mode operation
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Kai-Feng Huang, Yung-Fu Chen, C. Y. Cho, C. Y. Lee, P. H. Tuan, and C. C. Chang
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Materials science ,Physics::Instrumentation and Detectors ,business.industry ,Physics::Optics ,Laser ,Atomic and Molecular Physics, and Optics ,Power (physics) ,law.invention ,Longitudinal mode ,Nonlinear system ,symbols.namesake ,Optics ,law ,Attenuation coefficient ,symbols ,Optoelectronics ,Thermal lensing ,business ,Raman spectroscopy ,Raman scattering - Abstract
A cryogenically monolithic Nd:YVO4 self-Raman laser is experimentally explored and theoretically analyzed. The variation of the stimulated Raman scattering (SRS) threshold on the temperature is found to be nonlinear because the reduction of thermal lensing enlarges the cavity mode size. In spite of the nonlinear variation of the SRS threshold on the temperature, the overall SRS output power can be efficiently increased from 0.78 to 1.36 W for temperature decreasing from 285 to 80 K at an absorbed power of 17.2 W. More interestingly, the single-longitudinal-mode operation is experimentally achieved when temperature is lower than 125 K.
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- 2015
20. An energy adjustable linearly polarized passively Q-switched bulk laser with a wedged diffusion-bonded Nd:YAG/Cr⁴⁺:YAG crystal
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C Y, Cho, H P, Cheng, Y C, Chang, C Y, Tang, and Y F, Chen
- Abstract
An energy adjustable passively Q-switched laser is demonstrated with a composite Nd:YAG/Cr⁴⁺:YAG crystal by applying a wedged interface inside the crystal. The theoretical model of the monolithic laser resonator is explored to show the energy adjustable feature with different initial transmissions of the saturable absorber at the horizontal axis. By adjusting the pump beam location across the Nd:YAG crystal, the output pulse energy can be flexibly changed from 10.9 μJ to 17.6 μJ while maintaining the same output efficiency. The polarization state of the laser output is found to be along with the polarization of the C-mount pump diode. Finally, the behavior of the multi-transverse-mode oscillation is also discussed for eliminating the instability of the pulse train.
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- 2015
21. High-peak-power Optically-pumped AlGaInAs Eye-safe Laser with a Sandwiched Gain Chip Structure and a Silicon Wafer Output Coupler to Form a Compact Cavity
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Kai-Feng Huang, Yung-Fu Chen, C. Y. Cho, Chi-Ping Wen, Kuan-Wei Su, P. H. Tuan, and H. C. Liang
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Materials science ,Silicon ,business.industry ,Hybrid silicon laser ,chemistry.chemical_element ,Diamond ,Output coupler ,engineering.material ,Laser ,Round-trip gain ,Semiconductor laser theory ,law.invention ,Optics ,chemistry ,law ,engineering ,Optoelectronics ,Wafer ,business - Abstract
An intrinsic silicon wafer is exploited as an output-coupler to develop a high-peak-power optically-pumped AlGaInAs laser at 1.52 mm. The gain chip is sandwiched between diamond heat-spreaders and Si-wafer to form a compactly stack cavity.
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- 2015
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22. Exploring Air Breakdown Threshold and Temporal Dynamics by a Q-switched Mode-locked Nd:YAG Laser in a Statistical Approach
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C. Y. Cho, J. C. Tung, C. H. Wu, Yung-Fu Chen, Kuan-Wei Su, and P. H. Tuan
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Materials science ,business.industry ,Mode (statistics) ,Plasma ,Laser pumping ,Laser ,law.invention ,Pulse (physics) ,Optics ,Mode-locking ,law ,Nd:YAG laser ,Optoelectronics ,business ,Laser beams - Abstract
A Q-switched mode-locked Nd:YAG laser is utilized to explore air breakdown threshold in a statistical approach to be 0.64 TW/cm2. The temporal dynamics of induced plasma shows a sub-nanosecond delay to the incident Q-switched pulse.
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- 2015
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23. Optimal Temperature for the Cryogenically Cooled 946-nm Nd:YAG Laser with Monolithic Resonator
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Yung-Fu Chen, T. L. Huang, J. C. Tung, C. Y. Cho, and P. H. Tuan
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Resonator ,Materials science ,law ,business.industry ,Nd:YAG laser ,Diode-pumped solid-state laser ,Energy conversion efficiency ,Optoelectronics ,Laser pumping ,Laser ,business ,law.invention - Abstract
An optimal temperature of 130 K is observed for the cryogenic 946-nm monolithic Nd:YAG laser. The pump criterion is discussed and the output power is up to 24 W with conversion efficiency of 71%.
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- 2015
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24. The Effects of Stress Related Genes on Carcass Traits and Meat Quality in Pigs
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Z. D. Li, B. Y. Park, S. H. Yeon, S. T. Feng, I. H. Hwang, K. S. Min, C. K. Park, C. I. Kim, J. C. Park, Y. K. Kim, C. Y. Cho, S. S. Lee, H. J. Jin, and C. D. Kim
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Genetics ,RYR1 ,Animal science ,Longissimus ,Genotype ,Porcine stress syndrome ,Animal Science and Zoology ,Single-strand conformation polymorphism ,Restriction fragment length polymorphism ,Biology ,Breed ,Food Science ,Genotype frequency - Abstract
The current study was conducted to investigate the relationship between stress related gene and meat quality in pigs. A total number of 212 three-way cross bred (Landrace-YorkshirexDuroc) and 38 Duroc were sampled from the Korean pig industry to determine genotype frequency of porcine stress syndrome (PSS) and heat shock protein 70 kDa (HSP70) genes and their relationship with carcass traits and longissimus meat quality. Screen of HSP70 was performed by the single strand conformation polymorphism (SSCP) technique. Based on the analysis of restriction fragment length polymorphism (RFLP) in ryanodine receptor 1 (RYR1) gene, genetic disorder of PSS was related to a mutation at 18, 168 t h (C to T) of exon 17. There was no significant difference in ultimate meat pH and backfat thickness between HSP70 Kl-AA type and -BB type in pure Duroc breed. In Landrace-YorkshirexDuroc (L-YxD) cross bred pig, our results indicated that HSP70 derivate type in Duroc had a limited effect on backfat thickness, but L-YxD type had a noticeable linkage with HSP70 K1-AA and K3-AB. This tendency was also observed in hot carcass weight where HSP70 Kl-AA and K3-AB resulted in heavier weight with 86.3 kg compared to HSP70 Kl-AB and K3-BB of 74.3 kg. Results imply that stress related HSP70 genotype has a potential association with backfat thickness and carcass weight.
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- 2005
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25. Modelling end-pumped passively Q-switched Nd-doped crystal lasers: manifestation by a Nd:YVO_4/Cr^4+:YAG system with a concave-convex resonator
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Chi-Young Lee, C. Y. Cho, F. L. Chang, C. C. Chang, Yung-Fu Chen, C. L. Sung, P. H. Tuan, and Kuan-Wei Su
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010302 applied physics ,Physics ,business.industry ,Transcendental equation ,Saturable absorption ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Pulse (physics) ,law.invention ,010309 optics ,Resonator ,Optics ,law ,Fiber laser ,0103 physical sciences ,business ,Lasing threshold ,Pulse-width modulation - Abstract
A theoretical model for the passively Q-switched (PQS) operation which includes the spatial overlapping between the pump and lasing modes under the thermal lensing effect is developed to give a transcendental equation that can directly determine the critical parameters such as pulse energy, pulse repetition rate, and pulse width for the PQS performance. More importantly, an analytical function which gives the approximate solution for the transcendental equation as well as a specific critical criterion for good PQS operation are derived for practical analyses and design. A Nd:YVO4/Cr4+:YAG system with a concave-convex resonator which can achieve fairly stable PQS pulse trains even at a high pump level is further exploited to manifest the proposed spatially dependent model. The good agreement between the experimental results and the theoretical predictions is verified to show the feasibility of the proposed model for designing high-power PQS lasers with high accuracy.
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- 2017
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26. Nd:YLF laser at cryogenic temperature with orthogonally polarized simultaneous emission at 1047 nm and 1053 nm
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Kai-Feng Huang, Y. J. Huang, Yung-Fu Chen, C. Y. Cho, T. L. Huang, and S. M. Wen
- Subjects
Neodymium ,Materials science ,Absorption spectroscopy ,Optical Phenomena ,business.industry ,Slope efficiency ,Physics::Optics ,Lasers, Solid-State ,Laser ,Fluorescence ,Atomic and Molecular Physics, and Optics ,law.invention ,Crystal ,Cold Temperature ,Fluorides ,Optics ,Spectrometry, Fluorescence ,law ,Attenuation coefficient ,Fiber laser ,Lithium Compounds ,Optoelectronics ,Yttrium ,Absorption (electromagnetic radiation) ,business - Abstract
A Nd:YLF laser at cryogenic temperature is demonstrated for the first time with orthogonally polarized simultaneous emission at 1047 nm and 1053 nm. By exploring the temperature dependence of the fluorescence and the absorption spectra from the Nd:YLF crystal, the feasibility of simultaneous emission at low temperature is achieved. Due to the local heating from the pump absorption, the optimal temperature with respect to the pump power for balancing output powers of simultaneous emission is thoroughly explored. At the optimal temperature of 138 K, the total output power of the simultaneous emission can reach 3.1 W at an incident pump power of 7.9 W, corresponding to the optical to optical slope efficiency up to 43%.
- Published
- 2014
27. A review of diet formulation strategies and feeding systems to reduce excretory and feed wastes in aquaculture
- Author
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Dominique P. Bureau and C Y Cho
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Limiting factor ,Municipal solid waste ,Waste management ,business.industry ,Phosphorus ,Binding properties ,chemistry.chemical_element ,Aquatic Science ,Biology ,Whole grains ,Biotechnology ,Nutrient ,Aquaculture ,chemistry ,Ecosystem ,business - Abstract
Significant efforts should be devoted to reducingwaste outputs from aquaculture operations in orderto lower the environmental impacts of aquaculturein many parts of the world. Since most aquaculturewastes are ultimately from dietary origin, reductionof waste outputs should first be through improve-ments of diet formulation and feeding strategies.The first step in the production of feeds producingless solid waste is to eliminate poorly digestibleingredients (such as whole grain or grain by-products used as binders and fillers in the feedformulae) and to use highly digestible ingredientswith good binding properties. Further reduction ofsolid waste can then be achieved through carefulselection of the ingredients to improve apparentdigestibility and the nutrient balance of the feed.Nitrogen waste outputs can be reduced through thereduction of the digestible protein to digestibleenergy (DP/DE) ratio of the diet. Phosphorus wasteoutputs can be reduced through careful selection ofthe ingredients and optimization of the digestiblephosphorus content of the diet to meet therequirement of the fish but avoid greatly exceedingthis required level. Finally, feeding practices thatminimize feed wastage should be adopted since feedwastage can have a very significant impact onwaste outputs from fish culture operations.Keywords: aquaculture, waste, feed, feedingIntroductionOvert the past decade, the environmental impacts ofaquaculture operations have become a matter ofconcern for the public, the various levels ofgovernment and the aquaculture producers them-selves. Minimizing environmental impacts is there-fore a key factor in insuring long-term sustainabilityof the aquaculture industry.Containment and collection of wastes, both solidand dissolved, is very difficult and costly inaquaculture, as the wastes are rapidly dispersedinto the surrounding waters. The release of solidwastes, phosphorus (P) and nitrogen (N) fromaquaculture operations may have significant eutro-phication effects on receiving waterbodies andassociated ecosystems (Persson 1991). P wasteoutputs are a greater concern in freshwater sinceP is generally the most limiting factor for plant(algae) in that environment. N waste outputs aregenerally a greater concern in the marine environ-ment for the same reason (Persson 1991). Solidwastes (faecal material and wasted feed) settling tothe sediment can have an impact on the benthicecosystem of inland and marine waters (Gowen,Weston & Ervik 1991). Degradation of organicwaste by bacteria and other organisms leads to theconsumption of oxygen (O
- Published
- 2001
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- View/download PDF
28. A genetically encoded, fluorescent indicator for cyclic AMP in living cells
- Author
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Manuela Zaccolo, Roger Y. Tsien, Susan S. Taylor, Tullio Pozzan, L Feng, P A Negulescu, T Knapp, F. De Giorgi, and C Y Cho
- Subjects
Adrenergic beta-Antagonists ,Green Fluorescent Proteins ,Mutant ,CHO Cells ,Biology ,Kidney ,Transfection ,Second Messenger Systems ,Gene Expression Regulation, Enzymologic ,beta-Lactamases ,Green fluorescent protein ,Norepinephrine ,Bimolecular fluorescence complementation ,Genes, Reporter ,Cricetinae ,Cyclic AMP ,Animals ,Humans ,Cyclic AMP Response Element-Binding Protein ,Protein kinase A ,Effector ,Kinase ,Colforsin ,Isoproterenol ,Cell Biology ,Adrenergic beta-Agonists ,Cyclic AMP-Dependent Protein Kinases ,Propranolol ,Cell biology ,Luminescent Proteins ,Förster resonance energy transfer ,Bucladesine ,Microscopy, Fluorescence ,Biochemistry ,Mutagenesis ,COS Cells ,Cytogenetic Analysis ,Second messenger system ,Indicators and Reagents ,Adrenergic alpha-Agonists - Abstract
Cyclic AMP controls several signalling cascades within cells, and changes in the amounts of this second messenger have an essential role in many cellular events. Here we describe a new methodology for monitoring the fluctuations of cAMP in living cells. By tagging the cAMP effector protein kinase A with two suitable green fluorescent protein mutants, we have generated a probe in which the fluorescence resonance energy transfer between the two fluorescent moieties is dependent on the levels of cAMP. This new methodology opens the way to the elucidation of the biochemistry of cAMP in vivo.
- Published
- 1999
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- View/download PDF
29. Influence of output coupling on the performance of a passively Q-switched Nd:YAG laser with intracavity optical parametric oscillator
- Author
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Y. P. Huang, Y. J. Huang, C. Y. Cho, and Yung-Fu Chen
- Subjects
Materials science ,Amplifiers, Electronic ,business.industry ,Lasers ,Energy conversion efficiency ,Equipment Design ,Surface Plasmon Resonance ,Laser ,Atomic and Molecular Physics, and Optics ,law.invention ,Equipment Failure Analysis ,Wavelength ,Optical coating ,Optics ,Energy Transfer ,law ,Nd:YAG laser ,Oscillometry ,Reflection (physics) ,Optical parametric oscillator ,Optoelectronics ,Spontaneous emission ,business ,Lenses - Abstract
A singly-resonant intracavity optical parametric oscillator (OPO), pumped by a passively Q-switched Nd:YAG laser, is systematically investigated by means of a series of the output mirrors with various reflectivities for the fundamental wavelength at 1064 nm. Experimental results reveal that the output mirror with partial reflectivity instead of high reflection at 1064 nm not only is practicable to avoid the optical coatings damaged, but also enhances the dual-wavelength output efficiency for the OPO signal and fundamental laser waves. The overall optical-to-optical conversion efficiency is enhanced from 6.4% to 8.2% for the reflectivity decreasing from 99.8% to 90%.
- Published
- 2013
30. Compact high-pulse-energy passively Q-switched Nd:YLF laser with an ultra-low-magnification unstable resonator: application for efficient optical parametric oscillator
- Author
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Y. P. Huang, Y. J. Huang, Yi-Chun Chen, Kuan-Wei Su, C. Y. Cho, and Yung-Fu Chen
- Subjects
Materials science ,Amplifiers, Electronic ,business.industry ,Ti:sapphire laser ,Equipment Design ,Lasers, Solid-State ,Laser ,Atomic and Molecular Physics, and Optics ,Pulse (physics) ,law.invention ,Crystal ,Equipment Failure Analysis ,Resonator ,Wavelength ,Optics ,law ,Oscillometry ,Optical parametric oscillator ,Optoelectronics ,Laser beam quality ,business - Abstract
We exploit an ultra-low-magnification unstable resonator to develop a high-pulse-energy side-pumped passively Q-switched Nd:YLF/Cr4+:YAG laser with improving beam quality. A wedged laser crystal is employed in the cavity to control the emissions at 1047 nm and 1053 nm independently through the cavity alignment. The pulse energies at 1047 nm and 1053 nm are found to be 19 mJ and 23 mJ, respectively. The peak powers for both wavelengths are higher than 2 MW. Furthermore, the developed Nd:YLF lasers are employed to pump a monolithic optical parametric oscillator for confirming the applicability in nonlinear wavelength conversions.
- Published
- 2013
31. Integrated information technology for nuclear power plant lifecycle management
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C-Y. Cho, J. Han, K. Chin, W. Lee, D. Ryu, and H. Park
- Subjects
Engineering ,business.industry ,law ,Information technology management ,Nuclear power plant ,Biomedical Engineering ,Systems engineering ,Information technology ,Geriatrics and Gerontology ,business ,Gerontology ,law.invention ,Application lifecycle management - Published
- 2012
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32. Orthogonally polarized dual-wavelength Nd:LuVO4 laser at 1086 nm and 1089 nm
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C. Y. Cho, Y. J. Huang, Y. P. Huang, and Yung-Fu Chen
- Subjects
Materials science ,business.industry ,Lasers ,Equipment Design ,Polarization (waves) ,Laser ,Atomic and Molecular Physics, and Optics ,law.invention ,Crystal ,Equipment Failure Analysis ,Refractometry ,Optics ,law ,Fiber laser ,Optoelectronics ,Computer-Aided Design ,Dual wavelength ,Spontaneous emission ,Vanadate ,Vanadates ,business ,Fabry–Pérot interferometer - Abstract
A comparison between the fluorescence spectra of the Nd-doped vanadate crystals (Nd:YVO4, Nd:GdVO4, Nd:LuVO4) for the 4F3/2 → 4I11/2 transition is studied. We numerically analyze the condition of gain-to-loss balance via an uncoated intracavity etalon to achieve the dual-wavelength operation. We further experimentally demonstrate the orthogonally polarized dual-wavelength laser with a single Nd:LuVO4 crystal. The simultaneous dual-wavelength Nd:LuVO4 laser at 1085.7 nm in σ polarization and 1088.5 nm in π polarization is realized. At an incident pump power of 12 W, the average output power obtained at 1085.7 nm and 1088.5 nm is 0.4 W and 1.7 W, respectively.
- Published
- 2012
33. Effect of Fecal Retrieval Timing on Digestibility of Nutrients in Rainbow Trout Diet with the Guelph and TUF Feces Collection Systems
- Author
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S. Satoh, T. Watanabe, and C. Y. Cho
- Subjects
Animal science ,Nutrient ,Biochemistry ,Significant difference ,Rainbow trout ,Dry matter ,Aquatic Science ,Biology ,Leaching (agriculture) ,Digestion ,biology.organism_classification ,Feces ,Salmonidae - Abstract
The effect of feces collection intervals on the digestibility of feed in rainbow trout was determin-ed in order to substantiate nutrient loss from the feces collected by the Guelph System and TUF column. Feeding experiments were conducted using two different diets, and feces and surround-ing water were collected at 3, 6, 9, 12, and 15h after the final feeding. There was no significant difference in the apparent digestibility coefficient (ADC) of crude protein and lipid during collection intervals between data obtained from the Guelph System and TUF column. The ADC of dry matter and energy by the Guelph System exhibited the same trend as protein, but the ADC of dry matter and energy by TUF column at 3h was slightly lower than that at 6h or above. The results obtained have demonstrated that the effect of fecal retrieval intervals on the ADC is very minimal, and hardly and leaching of nutrients occurs from the feces collected with either the Guelph System or TUF column. Thus, it is proved that the Guelph System and TUF column are suitable equipment for collecting feces from salmonid fish to test digestibility.
- Published
- 1992
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34. Fish nutrition, feeds, and feeding: With special emphasis on salmonid aquaculture
- Author
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C. Y. Cho
- Subjects
Fishery ,Aquaculture ,business.industry ,General Chemical Engineering ,%22">Fish ,Biology ,business ,Food Science ,Commercial fish feed - Abstract
(1990). Fish nutrition, feeds, and feeding: With special emphasis on salmonid aquaculture. Food Reviews International: Vol. 6, Aquaculture, pp. 333-357.
- Published
- 1990
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- View/download PDF
35. 24-W cryogenically cooled Nd:YAG monolithic 946-nm laser with a slope efficiency >70%
- Author
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Kai-Feng Huang, Yung-Fu Chen, Chia-Yu Lee, C. Y. Cho, C. C. Chang, and P. H. Tuan
- Subjects
Materials science ,business.industry ,Energy conversion efficiency ,Slope efficiency ,Laser ,Atomic and Molecular Physics, and Optics ,law.invention ,Crystal ,Fluorescence intensity ,Optics ,law ,Fiber laser ,Optoelectronics ,business ,Absorption (electromagnetic radiation) ,Lasing threshold - Abstract
A high-power efficient monolithic Nd:YAG 946-nm laser is demonstrated at the cryogenic temperature. By exploring the absorption and the fluorescence spectra of the Nd:YAG crystal, it reveals the fact that the absorption bandwidth at 808 nm is narrowing and the fluorescence intensity at 1061 nm is significant enhanced when the temperature is decreased. The temperature dependence of the lasing threshold at 946 nm is found to display a minimum value near a temperature of 170 K. At an incident pump power of 34.5 W, the local heating leads the optimum temperature to be approximately 120 K and the maximum output power can reach 24.4 W with the conversion efficiency of 71% as well as the slope efficiency up to 75%.
- Published
- 2015
- Full Text
- View/download PDF
36. Muscle control associated with isometric contraction in different joint positions
- Author
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I S, Hwang and C Y, Cho
- Subjects
Adult ,Male ,Motor Neurons ,Recruitment, Neurophysiological ,Electromyography ,Physical Exertion ,Posture ,Weight-Bearing ,Reference Values ,Isometric Contraction ,Humans ,Female ,Muscle, Skeletal ,Ankle Joint - Abstract
The purpose of this study was to investigate the dependence of the surface EMG and varied internal effort due to different joint positions, and its muscle control strategies. Ten healthy subjects performed a fixed level (40% MVC measured in the neutral position) of isometric dorsiflexion and plantarflexion contraction in the ankle neutral, dorsiflexion, and plantarflexion positions. Quantitative EMG analyses with feature extraction in the time, frequency domain, as well as time-varying spectrum were employed to estimate recruitment pattern, code rating, and recruitment stationarity of activated motor units. Both RMS and median frequency of the tibial anterior (TA) and gastrocnemius (GS) were strongly dependent on foot position (p.001). Dominant firing rate of the TA muscle during the effort related isometric contraction was significant different with respect to ankle position (p.05). Irrespective of ankle position, the regression slope of median frequency across time was not different from zero for both TA and GS muscles (p.05). Identical torque exertion in different ankle positions called for considerable changes of control strategies of motor units. Possible mechanisms could be augmented excitatory central afferents and release of inhibition from Golgi tendon organs in compensation for biomechanical disadvantage in shorter muscle length.
- Published
- 2005
37. Fatty acid compositions of three microalga species
- Author
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K. T. Chue, L. N. Ten, M. Lee, S.-A. Yoo, Y. K. Oh, C. Y. Cho, and S.-G. Woo
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chemistry.chemical_classification ,food.ingredient ,biology ,Chemistry ,Food additive ,food and beverages ,Biomass ,Fatty acid ,Plant Science ,General Chemistry ,Chlorophyta ,biology.organism_classification ,General Biochemistry, Genetics and Molecular Biology ,food ,Algae ,Polyol ,Biofuel ,Botany ,Composition (visual arts) ,Food science - Abstract
Microalgae are promising targets for creating therapeutic and preventive drugs and biologically active food additives,for preparing biofuels, and for producing polymers based on renewable plant biomass [1–3]. In the last instance, microalgaein addition to soy, castor, and other plant oils can act as starting material for preparing the polyols that are required to ma nufacturepolyurethanes [3]. However, work in this area is practically in its infancy. An important parameter for assessing thebiotechnological potential of microalgae is the composition of saturated and unsaturated fatty acids.We studied several species of green alga (Order Chlorophyta) as renewable starting material for producing biodieselfuel and polyurethane plastics. Herein we present information on the fatty acid composition of four strains of these microalga e.Green algae
- Published
- 2012
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38. Diode-end-pumped solid-state lasers with dual gain media for multi-wavelength emission
- Author
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C. C. Chang, Yung-Fu Chen, and C. Y. Cho
- Subjects
Materials science ,business.industry ,Condensed Matter Physics ,Laser ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,law.invention ,Dual (category theory) ,Power (physics) ,Resonator ,Wavelength ,Optics ,Solid-state laser ,law ,Optoelectronics ,Laser power scaling ,business ,Instrumentation ,Diode - Abstract
We develop a theoretical model for designing a compact efficient multi-wavelength laser with dual gain media in a shared resonator. The developed model can be used to analyze the optimal output reflectivity for each wavelength to achieve maximum output power for multi-wavelength emission. We further demonstrate a dual-wavelength laser at 946 nm and 1064 nm with Nd:YAG and Nd:YVO4 crystals to confirm the numerical analysis. Under optimum conditions and at incident pump power of 17 W, output power at 946 nm and 1064 nm was up to 2.51 W and 2.81 W, respectively.
- Published
- 2014
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- View/download PDF
39. Efficient high-energy pulse generation from a diode-side-pumped passively Q-switched Nd:YAG laser and application for optical parametric oscillator
- Author
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Y. P. Huang, Y. J. Huang, and C. Y. Cho
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Energy conversion efficiency ,Laser ,Q-switching ,law.invention ,X-ray laser ,Resonator ,Optics ,law ,Nd:YAG laser ,Ultrafast laser spectroscopy ,Optical parametric oscillator ,Optoelectronics ,business ,Instrumentation - Abstract
We employ a convex–concave resonator to develop a high-pulse-energy diode-side-pumped passively Q-switched Nd:YAG laser with high extraction efficiency. At a diode pump energy of 227 mJ, the output laser pulse reaches 30 mJ with a pulse width of 6 ns at a repetition rate of 20 Hz. The optical-to-optical conversion efficiency is up to 13.2%. Based on the developed Nd:YAG laser oscillator, we further employ a monolithic KTP crystal to perform the optical parametric oscillator (OPO). With the 1064 nm input energy of 30 mJ, the OPO energy at 1573 nm is found to be 13.3 mJ, corresponding to an OPO conversion efficiency as high as 44.3%.
- Published
- 2014
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40. Rectal leiomyosarcoma diagnosed by endoscopic ultrasonography
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L J, Tseng, L R, Mo, Y T, Jao, C C, Tsai, T M, Young, and C Y, Cho
- Subjects
Diagnosis, Differential ,Leiomyosarcoma ,Male ,Rectal Neoplasms ,Humans ,Sensitivity and Specificity ,Aged ,Endosonography - Abstract
A 67 year-old man was admitted to the Tainan Municipal Hospital due to a protruding mass, usually noted during defecation. Digital examination revealed a single, smooth, large mass over the rectum, occupying almost the entire lumen. Colonoscopy, barium enema, and computed tomography (CT) demonstrated a submucosal tumor of the rectum. Endoscopic ultrasound (EUS) study showed that the tumor originated from the muscle layer. Based on the size, margin and echogenicity of the mass, a malignant neoplasm, probably leiomyosarcoma, was diagnosed. Post-operative histologic examination confirmed that the resected tumor was leiomyosarcoma. Existing ancillary procedures like colonoscopy, abdominal CT, magnetic resonance image (MRI), and barium enema are neither reliable nor accurate in locating which layer the lesion originates. Colonoscopic biopsy is disappointing since submucosal tumor is usually inaccessible. EUS study can provide us with a more distinct image with regards to tumor origin, size, margin and echogenicity. This report emphasizes the important role of EUS in the pre-operative diagnosis of submucosal tumors of the rectum. Furthermore, this tool can aid the surgeons whether wide excision or an abdomino-perineal resection should be performed.
- Published
- 1999
41. A cryogenically cooled Nd:YAG monolithic laser for efficient dual-wavelength operation at 1061 and 1064 nm
- Author
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Yung-Fu Chen, C. Y. Cho, P. H. Tuan, Kai-Feng Huang, and Y. T. Yu
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Physics::Optics ,chemistry.chemical_element ,Yttrium ,engineering.material ,Laser ,law.invention ,Optical pumping ,Crystal ,Wavelength ,Optics ,Coating ,chemistry ,law ,engineering ,Emission spectrum ,Spectroscopy ,business ,Instrumentation - Abstract
We experimentally explore the fluorescence spectra of the Nd:YAG (YAG: yttrium aluminum garnet) crystal at cryogenic temperatures to confirm the feasibility of dual-wavelength operation at 1061 and 1064?nm. Furthermore, a cryogenically cooled Nd:YAG crystal with coating to form a monolithic cavity is employed to investigate the performance of the dual-wavelength operation. At an incident pump power of 20?W, the output powers for each wavelength can simultaneously reach 6.0?W at the optimally balanced temperature of 152?K. The optimal temperature for balancing the output powers of the two wavelengths is experimentally determined as a function of the incident pump power intensity.
- Published
- 2013
- Full Text
- View/download PDF
42. Efficient dual-wavelength laser at 946 and 1064 nm with compactly combined Nd:YAG and Nd:YVO4 crystals
- Author
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C. C. Chang, C. Y. Cho, and Yung-Fu Chen
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Laser ,Power (physics) ,law.invention ,Crystal ,Optics ,law ,Power ratio ,Optoelectronics ,Dual wavelength laser ,business ,Instrumentation - Abstract
We originally employ a compact combination of a Nd:YAG crystal and a Nd:YVO4 crystal to develop an efficient dual-wavelength laser operating at 946 and 1064 nm. We exploit a short Nd:YAG crystal to generate 946 nm laser by reducing the reabsorption loss and a follow-up Nd:YVO4 crystal to generate a 1064 nm laser by absorbing the residual pump light. The output power ratio between the 946 and 1064 nm emissions can be flexibly adjusted from 0.3 to 0.9 by varying the separation between the two output couplers. At an incident pump power of 17 W, the total output power is generally higher than 5.2 W, with an overall optical-to-optical efficiency greater than 30%.
- Published
- 2013
- Full Text
- View/download PDF
43. 145 CHANGES IN OXYGEN COMSUMPTION RATES OF EMBRYOS IN KOREAN CATTLE
- Author
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Dongsoo Son, J. B. Kim, Suhnggwon Kim, Dongmin Kang, Sunho Choi, C. Y. Cho, Sang-Rae Cho, J. K. Son, and Changyong Choe
- Subjects
animal structures ,Embryogenesis ,chemistry.chemical_element ,Embryo ,Embryo culture ,Anatomy ,Reproductive technology ,Biology ,Oxygen ,Cryopreservation ,Andrology ,Endocrinology ,Human fertilization ,Reproductive Medicine ,chemistry ,embryonic structures ,Genetics ,Animal Science and Zoology ,Molecular Biology ,Embryo quality ,Developmental Biology ,Biotechnology - Abstract
Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. This study was carried out to identify whether oxygen consumption rates measured in bovine embryos using SECM can be used as a standard criteria to evaluate bovine embryo quality. Oxygen consumption of bovine embryos at various developmental stages was measured and analyzed using SECM and ANOVA analysis, respectively. We found that the oxygen consumption significantly increased in blastocyst-stage embryos compared to other stage embryos (from 2-cell stage to morula stage), indicating that oxygen consumption reflects the cell number (5.2-7.6 × 1014 mol-1 s-1 v. 1.2-2.4 × 1014 mol-1 s-1, P < 0.05). There was no significant difference between 2-cell-stage embryos and 8-cell-stage embryos. In the morula-stage embryos, the oxygen consumption of in vivo derived embryos was significantly higher than that of in vitro produced embryos (4.0 × 1014 mol-1 s-1 v. 2.4 × 1014 mol-1 s-1, P < 0.05). However, there was no significant difference in consumption of oxygen by in vivo and in vitro derived bovine blastocyst-stage embryos (P > 0.05). Good-quality embryos with grade 1 or 2 showed significantly higher oxygen consumption than grade 3 or 4 embryos. These results showed that SECM could measure oxygen consumption in bovine embryos and the oxygen consumption could reflect embryonic development stage and embryo quality.
- Published
- 2010
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- View/download PDF
44. Nutritional energetics in fish: energy and protein utilization in rainbow trout (Salmo gairdneri)
- Author
-
C Y, Cho and S J, Kaushik
- Subjects
Trout ,Animals ,Animal Nutritional Physiological Phenomena ,Dietary Proteins ,Energy Metabolism ,Salmonidae - Published
- 1990
45. A cryogenically cooled Nd:YAG monolithic laser for efficient dual-wavelength operation at 1061 and 1064 nm.
- Author
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C. Y. Cho, P. H. Tuan, Y. T. Yu, K. F. Huang, and Y. F. Chen
- Published
- 2013
- Full Text
- View/download PDF
46. Partial Replacement of Herring Meal with Soybean Meal and Other Changes in a Diet for Rainbow Trout (Salmo gairdneri)
- Author
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S. J. Slinger, H. S. Bayley, and C. Y. Cho
- Subjects
Meal ,biology ,digestive, oral, and skin physiology ,Soybean meal ,biology.organism_classification ,Feed conversion ratio ,Fish meal ,Herring ,medicine ,Rainbow trout ,Food science ,Salmo ,medicine.symptom ,Weight gain - Abstract
Growth rate, feed efficiency, and mortality were not adversely affected by reducing the level of herring meal in an open formula dry-pellet diet fed to rainbow trout (Salmo gairdneri) in aquaria through which 80–90% of the effluent water was recirculated. The herring meal was reduced from 35 to 18%, and the level of soybean meal increased from 10 to 39%. The fish gained 5.5 and 5.4 kg/100 fish from 8 to 40 wk of age on the high and low herring meal diets, respectively. Deletion of brewers' yeast, corn fermentation extractives, and whey powder from the diet with the higher level of herring meal increased weight gain to 7.0 kg/100 fish. When the fermentation by-products were removed from the diet with the lower level of fish meal the gain was reduced to 4.8 kg/100 fish. All the diets contained 4% of soybean or rapeseed oil or a marine oil; the type of oil did not influence the gains, but the conversion of feed to gain was most efficient for the diet containing the marine oil. The apparent digestibilities of the proximate components of three of the diets suggested that the fermentation by-products were not as digestible to the fish as the other components of the diet.
- Published
- 1974
- Full Text
- View/download PDF
47. Incorporation of Fatty Acids into Phosphatidylcholine by Acyl-CoA: l-acyl-sn-glycero-3-phosphorylcholine Acyltransferase in Liver of Rainbow trout, Salmo gairdneri
- Author
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J. Piekarski, S. J. Slinger, C. Y. Cho, and B. J. Holub
- Subjects
chemistry.chemical_classification ,Phosphorylcholine ,Phospholipid ,Fatty acid ,Biology ,Acylation ,chemistry.chemical_compound ,Acyl-CoA ,Biochemistry ,chemistry ,Acyltransferase ,Phosphatidylcholine ,lipids (amino acids, peptides, and proteins) ,Rainbow trout - Abstract
The formation of phosphatidylcholine by acylation of 1-acyl-sn-glycero-3-phosphorylcholine with fatty acids was demonstrated in microsomal preparations from the livers of rainbow trout (Salmo gairdneri). Maximum incorporation of fatty acids into phosphatidylcholine was highly dependent upon the addition of 1-acyl-sn-glycero-3-phosphorylcholine to the incubation medium when activated acids in the form of [14C]acyl-CoA esters were provided. The acyl-CoA: 1-acyl-sn-glycero-3-phosphorylcholine acyltransferase showed a selectivity for unsaturated (oleate) over saturated (palmitate) fatty acids when microsomes were prepared from rainbow trout acclimated to 7 or 15 C and assays conducted at both temperatures. The presence of an acyl-CoA hydrolase in the microsomal preparations is also reported. The possible function of the acyltransferase in rearranging the fatty acid composition of cellular phospholipid when fish are exposed to a change in environmental temperature is discussed.
- Published
- 1976
- Full Text
- View/download PDF
48. Uptake of hexachlorobenzene (HCB) from feed by rainbow trout (Salmo gairdneri)
- Author
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A J Niimi and C Y Cho
- Subjects
biology ,Trout ,Health, Toxicology and Mutagenesis ,Body Weight ,General Medicine ,Hexachlorobenzene ,Chlorobenzenes ,Lipid Metabolism ,Toxicology ,biology.organism_classification ,Pollution ,Diet ,chemistry.chemical_compound ,chemistry ,Environmental chemistry ,Animals ,Ecotoxicology ,Rainbow trout ,Salmo ,Microbial biodegradation ,Salmonidae ,Waste disposal ,Trophic level - Abstract
Hexachlorobenzene, C/sub 6/Cl/sub 6/, is an industrial chemical that has been used as a fungicide, and more extensively in the manufacture of styrene and rubber products. HCB is persistent and bioaccumulates once it enters the environment. Photodecomposition is minimal and microbial degradation has not been observed. HCB has a solubility of 6 ug/l in water although environmental concentrations in waters such as Lake Ontario are generally in the low ng/l range. Laboratory studies have demonstrated that HCB in water can be bioaccumulated through the food-chain. This study examined the uptake of HCB through food. Subadult rainbow trout (Salmo gairdneri) were fed prepared diets that contained HCB at concentrations in the low ug/kg range which approximated the levels in biota that occupy the lower trophic levels in waters such as the Lake Ontario environment.
- Published
- 1980
- Full Text
- View/download PDF
49. Effect of rearing density on thyroid and interrenal gland activity and plasma and hepatic metabolite levels in rainbow trout, Salmo gairdneri Richardson
- Author
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C. Y. Cho and John F. Leatherland
- Subjects
medicine.medical_specialty ,Triiodothyronine ,biology ,Triglyceride ,medicine.diagnostic_test ,animal diseases ,Metabolite ,Aquatic Science ,Hematocrit ,biology.organism_classification ,Trout ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Internal medicine ,medicine ,Rainbow trout ,Interrenal Gland ,Salmo ,Ecology, Evolution, Behavior and Systematics - Abstract
There were significant inverse correlations between rearing density of rainbow trout, Salmo gairdneri Richardson, and final body weight, plasma L-thyroxine (T4), truodo-L-tryronine (T3), cortisol and protein concentrations, plasma T4/T3 ratios and thyroid epithelial cell height. In addition, hepatosomatic indices and plasma free fatty acid concentrations were higher in fish reared at low (134 g 1−1) density compared with groups reared at medium (210g1−1) or high density (299g 1−1), and the post-feeding (3.5-4h) elevation in plasma glucose and triglyceride levels evident in trout maintained at low rearing density was not found in those fish reared at higher densities. There were no significant effects of rearing density on hematocrit, carcass composition, hepatic glycogen and lipid levels and interregnal nucleus size.
- Published
- 1985
- Full Text
- View/download PDF
50. Measurement of Oxidation in Fish Oil and its Effect on Vitamin E Nutrition of Rainbow Trout (Salmo gairdneri)
- Author
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C. Y. Cho, S. J. Slinger, and S. S. O. Hung
- Subjects
chemistry.chemical_classification ,medicine.diagnostic_test ,GPX3 ,Chemistry ,Thiobarbituric acid ,Vitamin E ,medicine.medical_treatment ,Aquatic Science ,Hematocrit ,Fish oil ,chemistry.chemical_compound ,Fish meal ,Biochemistry ,medicine ,Food science ,Peroxide value ,Ecology, Evolution, Behavior and Systematics ,Polyunsaturated fatty acid - Abstract
Peroxide value (PV), anisidine value, and thiobarbituric acid (TBA) number were compared as methods for measuring oxidation in fish oils and fish diets. PV was the method of choice for estimating oxidation in the oil. Methods for measuring moderately oxidized oil after being mixed in the diets are discussed. Analyses of dietary samples revealed that the TBA numbers and percentages of polyunsaturated fatty acids were not greatly altered by the addition of moderately oxidized fish oil and by the long-term storage (24 wk) of the diet at room temperature. However, endogenous α-tocopherol levels in the diet were significantly (P
- Published
- 1980
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