• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.103-104
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• 2006

Wear of valve seating face and seat insert seating face influence the performance of engine, so they are important. To manufacture good quality valve and seat insert which have wear resistance the relations between wear factors and wear of the two seating faces have to be inspected. Cycle number is one of the important wear factors wearing the two seating faces and it can translate into mileage in rear car. But little is blown. Test variable is only cycle number and the cycle numbers are $2.0{\times}10^6,\;4.0{\times}10^6\;6.0{\times}10^6,\;8.0{\times}10^6$. And the other test conditions were fixed. Rmax of valve seating face and seat insert seating face increase linearly as cycle number is increased. Rmax of valve seating face were smaller than seat insert seating face in each cycle number. Reaction production by tribological reaction and sliding wear was found on the two faces.

• 한국발생생물학회지:발생과생식
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• 제23권4호
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• pp.323-331
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• 2019

In this study, an experiment was conducted to investigate the annual reproductive cycle of a Korean flat bittering, Acheilognathus rhombeus, from Ogok-myeon located in Seomjin River. The reproductive cycle was examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), and developmental characteristics of female and male gonads. The maximum GSI was found to be 3.50±0.53 and 1.36±0.14 for females and males, respectively, when the water temperature and day light was 16.9℃ and 11.3 hours, respectively in October 2018. On the other hand, the minimum GSI was found to be 0.16±0.09 and 0.69±0.15 for males and females in December 2018 and February 2019, respectively. The ovipositor of females appeared from August to November 2018. We compared and calculated the stages of germ cell developmental characteristics in the testis and ovaries to determine the reproductive cycle. According to the result, we classified the female A. rhombeus reproductive cycle into four phases, which are ripe and spawning phase (October), degenerative phase (November to December), growing phase (January to March) and mature phase (April to September). The annual reproductive cycle of male A. rhombeus was categorized into four phases: mature phase (June to October), degenerative phase (November to March), resting phase (April) and growing phase (May). The Korean flat bittering is an autumn-spawner as the main spawning season in October. In male, testicular spermatogonia appeared all year-round, and the ripe and releasing phase, which is characteristics of the spawning season in other fish, did not appear.

• Asian-Australasian Journal of Animal Sciences
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• 제17권7호
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• pp.919-923
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• 2004

Ultrasonographic study was undertaken to establish the echogenecity and size of reproductive organs of 18 cycling buffaloes of different parities and compared with the sizes measured by palpation per rectum at estrus (day 0), met estrus (day 2), mid diestrus (day 10) and late diestrus (day 16). The overall mean size of cervix, uterine body, right horn, left horn, right ovary and left ovary measured by palpation per rectum were 2.70$\pm$0.43, 2.36$\pm$0.36, 2.17$\pm$0.37, 2.12$\pm$0.38, 2.63$\pm$0.41 and 2.72$\pm$0.37 cm, respectively. The corresponding ultrasonographic observations were 2.10$\pm$0.40, 1.85$\pm$0.30, 1.73$\pm$0.36, 1.64$\pm$0.37, 2.16$\pm$0.36 and 2.29$\pm$0.38 cm respectively. Variations in the size of genitalia due to stages of estrous cycle were non-significant. The size of genitalia measured by palpation per rectum was significantly higher (p<0.05) than by ultrasonography. However, there was linear positive correlation (r=+0.87) in the measurements by the two techniques. The ultrasonographic characteristics of tubular genitalia revealed different echogenic gray shades around the nonechogenic (black) central area of lumen depending upon the stage of cycle. The ovarian stroma appeared as hyperechoic (white) area with nonechogenic (black) follicle. The corpus luteum (CL) exhibited different echogenic texture viz. grayish black, grayish granular and grayish white at met estrus, mid diestrus and late diestrus, respectively. Therefore, ltrasonography can be effectively employed to record the exact size and echotexture of the buffalo genitalia during different stages of estrous cycle.

• 상하수도학회지
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• 제29권1호
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• pp.11-21
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• 2015

When designing Water Distribution System (WDS), determination of life cycle for WDS needs to be preceded. And designer should conduct comprehensive design including maintenance and management strategies based on the determined life cycle. However, there are only a few studies carried out until now, and criteria to determine life cycle of WDS are insufficient. Therefore, methodology to determine life cycle of WDS is introduced in this study by using Life Cycle Energy Analysis (LCEA). LCEA adapts energy as an environmental impact criterion and calculates all required energy through the whole life cycle. The model is build up based on the LCEA methodology and model itself can simulate the aging and breakage of pipes through the target life cycle. In addition the hydraulic analysis program EPANET2.0 is linked to developed model to analyze hydraulic factors. Developed model is applied to two WDSs which are A WDS and B WDS. Model runs for 1yr to maximum 100yr target life cycle for both WDSs to check the energy tendency as well as to determine optimal life cycle. Results show that 40yr and 54yr as optimal life cycle for each WDS, and tendency shows the effective energy is keep changing according to the target life cycle. Introduced methodology is expected to use as an alternative option for determining life cycle of WDS.

• 플랜트 저널
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• 제15권2호
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• pp.42-45
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• 2019

용융탄산염 연료전지는 폐열의 온도가 높아 하부 사이클을 구성하여 효율을 높일 수 있다. 이러한 목적으로 연료를 재순환하는 용융탄산염 연료전지에 하부 사이클로 증기 터빈 사이클을 적용한 선행 연구가 있었다. 본 연구는 하부 사이클을 증기 터빈 사이클에서 초임계 이산화탄소 사이클로 대체하는 것을 고려하였다. 그리고 출력을 비교하여 하부 사이클을 대체하는 것에 대한 검토를 하였다. 그 결과 현재 개발 단계의 초임계 이산화탄소 사이클의 출력은 증기 터빈 사이클보다 낮지만, 이론적으로 증기 터빈 사이클보다 출력이 더 커질 수 있음을 확인하였다. 만약 초임계 이산화탄소 사이클이 터빈의 등엔트로피 효율을 89%, 압축기의 등엔트로피 효율을 83%, 복열기의 유용도를 0.9의 수준으로 향상 시킨다면 증기 터빈 사이클과 동등한 출력을 낼 수 있다.

• 대한원격탐사학회지
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• 제38권1호
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• pp.33-43
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• 2022

This study presents a method to restore an optical satellite image with distortion and occlusion due to fog, haze, and clouds to one that minimizes degradation factors by referring to the same type of peripheral image. Specifically, the time and cost of re-photographing were reduced by partially occluding a region. To maintain the original image's pixel value as much as possible and to maintain restored and unrestored area continuity, a simulation restoration technique modified with the Cycle Generative Adversarial Network (CycleGAN) method was developed. The accuracy of the simulated image was analyzed by comparing CycleGAN and histogram matching, as well as the pixel value distribution, with the original image. The results show that for Site 1 (out of three sites), the root mean square error and R² of CycleGAN were 169.36 and 0.9917, respectively, showing lower errors than those for histogram matching (170.43 and 0.9896, respectively). Further, comparison of the mean and standard deviation values of images simulated by CycleGAN and histogram matching with the ground truth pixel values confirmed the CycleGAN methodology as being closer to the ground truth value. Even for the histogram distribution of the simulated images, CycleGAN was closer to the ground truth than histogram matching.

• PNF and Movement
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• 제20권1호
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• pp.91-101
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• 2022

Purpose: The purpose of this study was to examine the effect of cycle ergometer exercise inducing movement of the affected side on knee joint function after total knee arthroplasty (TKA). Methods: The primary experiment was conducted on 19 members of the cycle ergometer exercise group to measure the muscle activity of the rectus femoris, hamstring, tibialis anterior, and gastrocnemius muscles during cycle ergometer exercise that induced the affected side's movement. In the second experiment, after receiving physiotherapeutic intervention for 30 min, the general bicycle exercise group and cycle ergometer exercise group performed the corresponding exercise for 15 min, 5 times per week, for 2 weeks. The ROM, muscle strength, pain, and balance were then measured and compared between the two groups. Results: In the results of the primary experiment, cycle ergometer exercise inducing movement of the affected side showed a significantly larger increase in the activity of leg muscles (rectusfemoris, hamstring, tibialis anterior, gastrocnemius) on the affected side than the general bicycle exercise (p <0.05). In the second experiment, the cycle ergometer exercise group showed a significantly larger increase in range of movement of affected side knee flexion and muscle strength of affected side knee flexion, knee extension, and plantarflexion than the general bicycle exercise (p <0.05). No significant between-group difference was observed in pain and balance before or after the intervention (p >0.05). Conclusion: Cycle ergometer exercise inducing movement of the affected side increases use of the muscles around the affected side knee joint after TKA more than general bicycle exercise and produces better effects for enhancing muscle strength. The application of cycle ergometer exercise inducing movement of the affected side is expected to reduce the patients' unbalanced use during the early postoperative period and help them to quickly return to normal daily life through rapid muscle strength recovery.

• Reproductive and Developmental Biology
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• 제28권1호
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• pp.53-57
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• 2004

The study was carried out to investigate the effects of morphology, reproductive cycle, incubation time and activation of oocytes on in vitro maturation of cat oocytes and development of IVM/IVF embryos. The results were summarized as follows: 1. When recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage), the developmental rates of oocytes to GV and MI stage were 72.5% and 27.5%, 57.5% and 7.5%, 62.5% and 17.5%, respectively. 2. The developmental rates of oocytes with cumulus cells to GV and MI stage in different conditions of incubation (5% $CO_2$ , 95% $O_2$ and 10% $CO_2$, 90% $O_2$) were 70.0% and 27.5%, 52.5% and 20.0%, 55.0% and 12.5%, respectively. 3. The developmental rates to GV and MI oocytes when cultured at different time of incubation (17∼20, 21∼24, 25∼28 and 29∼32 h) were 67.5% and 20.0%, 67.5% and 30.0%, 62.5% and 22.5%, 65.0% and 15.0%, respectively. 4. The fertilization and cleavage rates of freshly collected oocytes with and without cumulus cells were 72.5% and 25.0%, 37.5% and 7.5%, respectively. The rates were greater in oocytes with cumulus cells than those without cumulus cells. 5. The fertilization and cleavage rates of oocytes recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage) were 75.0% and 25.0%, 40.0% and 7.5%, 50.0% and 15.0%, respectively.

• Clinical and Experimental Reproductive Medicine
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• 제49권3호
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• pp.210-214
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• 2022

Objective: Platelet-rich plasma (PRP) therapy has received a considerable attention as an adjunct to fertility treatments, especially in women with very low ovarian reserve and premature ovarian insufficiency. Although recent studies have demonstrated that PRP led to improvements in folliculogenesis and biomarkers of ovarian reserve, the effect of intraovarian PRP administration on embryo genetics has not been studied. Methods: We report a pilot study of patients who had preimplantation genetic testing for aneuploidy (PGT-A) before and then within 3 months following PRP administration. Twelve infertile women with at least one prior failed in vitro fertilization (IVF) cycle underwent ovarian stimulation (cycle 1) with a gentle stimulation protocol and PGT-A performed at the blastocyst stage. Following cycle 1, autologous intraovarian PRP administration was performed. Within 3 months following PRP administration, the patients underwent cycle 2 and produced blastocysts for PGT-A. The percentage of euploid embryos between both cycles was compared. Results: The mean age of all participants was 40.08±1.46 years, and their mean body mass index was 26.18±1.18 kg/m². The number of good-quality embryos formed at the blastocyst stage was similar between cycle 1 and cycle 2 (3.08±0.88 vs. 2.17±0.49, respectively; p=0.11). Among all patients in cycle 1, 3 of 37 embryos were euploid (8.11%) while in cycle 2, 11 out of 28 embryos were euploid (39.28%, p=0.002). Three clinical pregnancies were noted among this patient group. Conclusion: This novel study is the first to present an improvement in the embryo euploidy rate following intraovarian PRP application in infertile women with prior failed IVF cycles. The growth factors present in PRP may exhibit a local paracrine effect that could improve meiotic aberrations in human oocytes and thus improve euploidy rates. Whether PRP improves live birth rates and lowers miscarriage rates remains to be determined in large trials.

• 한국산업융합학회 논문집
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• 제19권4호
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• pp.198-205
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• 2016

For the study on the ion exchange of nickel hexacyanoferrate(NiHCNFe) electrode with the several cations, the film of hexacyanoferrate was prepared on the bare nickel surface by the electrochemical and chemical methods in the solution composed with 5mM K3Fe(CN)6 and 100mM KNO3. To compare the capability of the ion exchange of NiHCNFe film electrode, the repeated cyclic voltammograms were measured in the 0.5M cation nitrate solutions at $25^{\circ}C$ and pH7. It was found that the capacity of the electrochemically derivatized NiHCNFe reduced in the rate of 0.5~0.7%/cycle and was nearly exhausted at the 150th potential cycle. Better result was obtained from that the capacity loss of the chemically assembled NiHCNFe was less than 0.02%/cycle for 5,000cycles. Furthermore, the residual capacity was more than 30% at the 5,000th cycle.