Correlation Between Primary Si and Silicide Refinement Induced by Ultrasonic Treatment of Multicomponent Al–Si Alloy Containing Ti, Zr, V, and P

Jae‑Gil Jung,Young‑Hee Cho,Tae‑Young Ahn,Jae‑Hee Yoon,Sang‑Hwa Lee,Jung‑Moo Lee 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

The correlation between primary Si and silicide refinement induced by ultrasonic treatment (UST) of multicomponent Al–Sialloy containing Ti, Zr, V, and P was investigated. UST significantly refined the primary Si phase owing to cavitation-inducedwetting and deagglomeration of MgAl2O4particles. Lowering the UST finish temperature caused deterioration of the degreeof primary Si refinement, instead leading to silicide refinement. Cavitation-induced silicide nucleation on wetted MgAl2O4consumed the MgAl2O4particles, particularly in the case of primary Si nucleation. Similarly, the formation of an AlP phaseon the silicide phase reduced the nucleation efficiency of the AlP phase. Poisoning of the MgAl2O4and AlP phases by thesilicide phase was responsible for the deterioration in primary Si refinement. Room-temperature tensile strength and hightemperatureelongation were increased by UST and were dependent on the size of primary Si.

양식 은어의 미포자충 감염예에 대한 병리조직학적 관찰

조병열,강형길,강효주,류갑민,이재영,박남규,허민도 한국어병학회 2003 한국어병학회지 Vol.16 No.1

1998년 9월 말경, 경남 지역의 양식 은어(Plecoglossus altivelis)에서 미포자충증이 발생하였다. 채집 당시, 하루 약 200마리씩의 폐사가 10일째 진행되고 있었으며 약 10%의 누적폐사율을 나타내었다. 병어는 입올림을 하거나 기면 상태에 있었으며, 대부분 체색흑화 및 복부팽만 소견을 보이고 있었다. 아가미, 아가미 뚜껑, 각종 내장, 복강벽 및 생식소에 직경 1~3㎜의 흰색 결절이 다수 형성되어 있었다. 감염 어종, 기생충의 형태 및 xenoma 분포 장기의 다양성에 근거하여 Glugea plecoglossi에 의한 감염증으로 추정되었다. 병리조직학적 검사를 실시한 결과, 광범위한 장기에 걸쳐 xenoma를 형성하고 있었으나 xenoma 인접조직에 변성 변화는 없었다. 아가미 새변, 비장, 두신 및 체신의 조혈영역에 심한 울혈 소견이 인정되었고, 간장, 심근 및 신세뇨관 국소에는 응고 내지 액화괴사 소견이 확인되었다. 따라서, xenoma의 인접조직에 대한 물리화학적인 영향보다는 xenoma형성 장기 및 조직에 야기된 국소 순환장애가 은어의 폐사와 직접적인 관련을 갖는 것으로 사료되었다. On September in 1998, a microsporidian infection was recognized in ayu, Plecoglossus altivelis, farmed on Kyongnam province of South Korea. Cumulative mortality was around 10% in 10 days. Infected fish which were piping for air near the surface of the water or in the asphyxic, lethargic condition revealed darkening of body and abdominal distention. Numerous whitish nodules up to 3㎜ in size were observed throughout most of body organs and tissues including gill, operculum, peritoneal wall and organs. Xenomas were also histologically confirmed in multiple internal organs with the evidences suggesting circulatory disturbance. Based on the morphology of spore and xenoma, and the distribution of xenomas in organs and tissues, this disease was diagnosed to be a microsporidiosis caused by Glugea plecoglossi. The mortality might be deeply related to the local circulatory disturbance by xemonas rather than the mechano-chemical effect of xenomas on adjacent tissues.

상사성을 고려한 배수재 설치 연약점토 지반의 원심모델링

유남재,홍영길,정길수,조한기 강원대학교 산업기술연구소 2007 産業技術硏究 Vol.27 No.A

This paper is results of experimental research on the effect of application of similarity related to permeability of soil on the consolidation behavior as centrifuge modeling of consolidation is performed with the centrifuge model facility. In this research, the permeability of soil was controlled by changing the viscosity of porewater as the mixed water with glycerin was used during the centrifuge model experiments. The effect of drainage path on consolidation was investigated by installing the vertical drains. A serise of centrifuge model tests with conditions of single vertical and radial horizontal drainage were carried out. Kaolinite and Jumunjin standard sand were used as soft clay and surcharges respectively during tests. For testing condition of single vertical drainage considering similarity of permeability, it was found that consolidation with mixed porewater with glycerin was delayed in comparisons with test results with water only. For conditions of horizontal drainage with vertical drains, a low permeability by changing the viscosity of pore water resulted in delayed degree of consolidation at an initial stage of consolidation. But, it predicted not much differences in settlement as long as the consolidation time was sufficiently long enough to finish consolidation. Consequently, it was found that similarity in permeability should be considered to be critical for the case of centrifuge model experiments related to consolidation with long drainage path.

주파수 선택성 다중경로 페이딩 채널에서 Near/Far 영향을 받는 Multi-Carrier CDMA Trellis Coded 16 QAM 시스템의 성능 해석

노재성,강희조,김춘길,김언곤,조성준 대전산업대학교 반도체기술연구소 2000 半導體技術硏究所報 Vol.2 No.-

본 논문에서는 주파수 선택성 다중경로 페이딩과 Near/Far 영향을 받는 Multi-Carrier CDMA 시스템의 성능을 분석하였다. 성능 분석을 위해 사용한 파라미터들은 Multi-Carrier의 수, 다중사용자의 수, RAKE 수신기의 가지수, 주파수 선택성 다중경로 페이딩의 감쇄지수, 그리고 CDMA 다중사용자의 분포와 세기이다. Multi-Carrier CDMA 시스템에서 Near/Far 영향을 분석하기 위하여 3가지의 간섭 분포 모델을 설정하였다. 첫 번째 모델은 다중사용자가 간섭과 대 반송파 비인 I/C를 -4 dB에서 4dB 사이에서 2dB씩의 차이를 가지며 20%씩 균일하게 분포하는 경우이다. 두 번째 모델은 다중사용자가 I/C 비를 -2 dB에서 2 dB 사잉에서 2 dB씩의 차이를 가지며 33.3%씩 균일하게 분포하는 경우이다. 그리고 세 번째 모델은 모든 다중사용자가 I/C가 0 dB로 신호 전력과 간섭 전력이 동일하게 분포하며 전력이 완전하게 제어된 경우이다. 그리고 본 논문에서는 주파수 선택성 다중경로 페이딩의 영향을 감소시키기 위하여 RAKE 수신기를 채용한 Multi-Carrier CDMA 시스템을 제안하였다. 이 시스템에서는 제시한 3가지의 간섭 분포 모델중에서 세 번째 모델(완전 전력제어가 된 경우)이 가장 좋은 성능을 나타내었고, 간섭파의 전력과 신호파의 전력차이가 적을수록 희망 신호에 영향을 주는 간섭 신호의 전력량이 적어서 Multi-Carrier CDMA 시스템의 성능이 향상됨을 알 수 있었다. The performance of a multi-carrier CDMA system is analyzed considering frequency selective multipath fading and Near/Far effects. The number of multicarrier, multiuser, and arms of RAKE receiver, and the decay ratio of frequency selective multipath fading are used as a parameter for the performance analysis. Moreover, the distribution and the strength of multiuser interference are also considered. To evaluate the Near/Far effects in a multi-carrier CDMA system, three distribution models are assumed. In the first model, Interference to Carrier Ratio, I/C, ranges from -4 dB to 4dB, and at each 2 dB interval, 20% of multiuser is assumed to be uniformly distributed. In the second one, I/C ranges from -2 dB to 2dB, and 33.3% of multiuser is assumed to be equally dispersed at each 2dB interval. The third model is 0 dB of I/c, that is, with perfect power control, multiuser are assumed to be evenly located. In this paper, multi-carrier CDMA system adopting RAKE receiver is proposed to mitigate the frequency selective multipath fading. From the results, the third model(i.e. perfect power control) shows the best perfomance, and the narrower range of I/C causes the less effects to the desired signal, which reads to the better performance.

12주간의 등속성 및 스트레칭 운동이 노인 여성의 체력요인에 미치는 영향

임순길,조재혁 龍仁大學校 體育科學硏究所 2003 體育科學硏究論叢 Vol.13 No.2

The purpose of this study is to find whether isokinetic training and stretching program has a good effect on decrease of physical factors caused by aging and find the training program which has a good effect on physical factors. The subjects of this study are 15 elderly women aged from 61 to 65. The subjects were distributed into two groups, isokinetic training program group(n=8) and stretching group(n=7) respectively. The subjects of isokinetic training group participated in lower extremities isokinetic training program three times a week for 12 weeks, and the subjects of stretching group participated in stretching program three times a week for 12 weeks. Changes of physical factors(power, agility, gait speed, and balance) after training were analyzed through repeated measures anova. Results of this study are following: 1. There was a significant difference in balance test after 12 week training between stretching group and isokinetic group. 2. There was a significant difference in power test after 12 week training between isokinetic group and stretching group. 3. There was a significant difference in agility test after 12 week training between isokinetic group and stretching group. 4. There was a significant difference in gait speed test after 12 week training between stretching group and isokinetic group.

풍향에 따른 아파트 단지내 기체유동 및 온도 분포해석

변용섭,조재광,엄태인,장재덕,이상길 大田産業大學校 2000 한밭대학교 논문집 Vol.17 No.1

In this study, velocity and temperature profiles are calculated on the apartment complex at Dunsan area in Taejon using FLUENT code based on computational fluid dynamics (CFD). Input weather conditions which maximum atmospheric is 38.6℃, wind speed is 1.7m/sec, wind direction is west-south-west and maximum wall of apartment is 58.0℃ in summer are used to calculate the results. The simulation results are as follow ; First. velocity vectors at vertical cross section of apartment complex are influenced by the thermal buoyancy force in hot wall of apartment due to weak wind speed in the case of wind direction : west-south-west, south-west, west. Second, temperature profiles at vertical cross section of apartment complex are strongly influenced by the wind direction. Atmospheric temperature in wide area is higher 1℃ in south-west wind direction than west wind direction. Calculation results show that island in enormous apartment complex in summer. Third, temperature profiles at horizontal cross section of apartment complex present wider and more definite high temperature area than at vertical cross section of apartment complex according to wind direction. This consequence shows the effect of convective heat transfer in the rear heated wall of apartment is dominant by solar radiation. Fourth, It is necessary that an arrangement of apartments with a view of wind direction and distance of each apartments to reduce heat island in apartment and industrial factory complex in the condition of same apartment direction and area capacity. And an arrangement of apartments considering wind direction is able to enhance convective heat transfer between heated wall and wind.

유산망아지에서 말herpesvirus 의 면역조직학적 및 immunogold 기법에 의한 전자현미경적 진단

신태균,이두식,진재광,임윤규,조길재 濟州大學校 農科大學 動物科學硏究所 1997 動物科學論叢 Vol.12 No.1

To investgate the causative Virus in aborbon of horse in Cheju, we examined the spleen of affected foal by immunohtochemistq and immunogold electron microscopy using EHV - specific antisera. Immunohistochemical staining revealed that a large number of EHV immunoreadive cells were deteded in the red pulp as well as in the sinudoidal cells in the affected spleen. By the immunogold electron microxopy(EM) of crude preparation of EHV culture, electron dense gold paricles were labelled along the envelope of amorphous virus parhcles with vanng sizes of 50-200nm. We suppose that immunohistochemical method is good for the diagnosis of tissues in EHV infections, and immunogold EM is recommended for the study of virus dia gnosis of fluid specimen as well as the ultrastustural study.

말의 피부사상균증 및 피부 mycoflora에 관한 연구

최원필,이헌준,조길제,하태영,Choi, Won-pil,Lee, Hun-jun,Cho, Gil-jae,Ha, Tae-young 대한수의학회 1996 大韓獸醫學會誌 Vol.36 No.2

This study was carried out to determine the causative agent of dermatophytosis in 7 horses, and to examine the skin mycofloras on 84 healthy and 7 diseased horses which were derived from Jae-ju and Kyonggi, Korea in 1994~1995. Specimens of hair and scale were collected from skin lesions(or normal skins) and inoculated directly on potato dextrose agar and mycobiotic agar. These agar plates were incubated at $25^{\circ}C$ for 2 weeks. Growing fungi were isolated and identified by the morphological and nutritional characteristics. Lesions were found on the hind legs of an infected horses and each lesion was round or oval(1~4 cm) in shape accompanied by severe itching. The causative agent of the 7 equine dermatophytosis was identified as Trichophyton equinum. The skin mycofloras were Penicillium(69.0%), Aspergillus(63.2%), Cladosporium(51.7%), Fusarium(31.0%), Mucor(28.7%), Absidia(18.4%), Alternaria(17.2%), Acremonium(11.5%), Paecilomyces and Phycomyces(6.9%), Rhizopus(5.6%), Trichoderma(4.6%), Scopulariopsis and Trichophyton(3.5%), Beauveria(2.3%), Tritiracheum, Sporothrix, Curvularla, Aureobasidium and Chaetomium(1.2%), and Yeast(27.6%).

A Non-binary C-R Hybrid DAC for 12 b 100 MS/s CMOS SAR ADCs with Fast Residue Settling

Jae-Geun Lim,Je-Min Jeon,Jun-Ho Boo,Yoon-Bin Im,Jae-Hyuk Lee,Sung-Han Do,Young-Jae Cho,Michael Choi,Gil-Cho Ahn,Seung-Hoon Lee 대한전자공학회 2021 Journal of semiconductor technology and science Vol.21 No.4

This work proposes two versions of a 12 b 100 MS/s successive-approximation register (SAR) ADC based on a non-binary C-R hybrid DAC. The proposed DAC applies a non-binary weighted capacitor array to the 7 MSBs to meet the settling requirement of the DAC output and determines the remaining 5 LSBs using the reference voltages generated from a simple resistor string to reduce the DAC area significantly. The Version 1 ADC in a 28 ㎚ CMOS adopts a synchronous SAR logic and a comparator with a tail capacitor and a reset switch to minimize power consumption. The Version 2 ADC in a 0.18 ㎛ CMOS employs an asynchronous SAR logic with simple meta-stability correction logic to achieve high-speed operation. The Version 1 ADC which has an active die area of 0.042 ㎟ shows a maximum signal-to-noise-and-distortion ratio (SNDR) and spurious-free dynamic range (SFDR) of 62.3 and 77.3 ㏈, respectively, consuming 1.3 ㎽ with a 1.0 V supply voltage. The Version 2 ADC is based on a similar analog circuit topology, showing a maximum SNDR and SFDR of 60.1 and 73.5 ㏈, respectively, with an active die area of 0.30 ㎟, operating at a 1.8 V supply voltage.

Validation of Microsatellite Markers for Routine Dog Parentage Testing in Korea

Gil-jae Cho,Young-jae Lim,Bong-hwan Kim 대한수의학회 2003 대한수의학회 학술대회발표집 Vol.2003 No.-