• 한국전자파학회논문지
• /
• 제8권4호
• /
• pp.323-331
• /
• 1997

본 논문에서 고효율 평형 증폭기는 기본적으로 두 개의 FET와 입력 전력 분배기, 출력 전력 결합기, 입력 정합회로, 출력 정합회로, 2차 고조파 상호 연결 회로로 구성된다. 2차 고조파 상호 연결 회로는 FET출력 정합회 로의 출력 단자사이에 끼워지므로 2차 고조파 정재파는 두 FET 출력사이에서 발생된다. 전기벽 종단은 단락 회로 종단과 등가이고 고효율을 얻기 위해 펼요한 FET 출력 종단 조건 실현이 가능하다. 실험 결과 증폭기는 1.75 G GHz에 맞추어 설계, 제작되었고 실험 결과 2차 고조파 성분은 기본파에 비해 약 20 dBc 이상을 나타냈고 왜곡 이 1% 이하이다. 또한 약 3W의 출력을 얻었고, 이 출력점에서 75 %의 효율을 얻을 수 있었다. 증폭기의 입력, 출력 VSWR은 각각 1. 27, 1.18을 나타내었다.

• Clinical and Experimental Reproductive Medicine
• /
• 제43권1호
• /
• pp.38-43
• /
• 2016

Objective: The number of assisted reproductive technology (ART) clinics, ART cycles, clinical pregnancy rate (CPR), and number of newborns conceived using ART have steadily increased in South Korea. This aim of this study was to describe the status of ART in South Korea between January 1 and December 31, 2011. Methods: A localized online survey was created and sent to all available ART centers via email in 2015. Fresh embryo transfer (FET) cases were categorized depending on whether standard in vitro fertilization, intracytoplasmic sperm injection (ICSI), or half-ICSI procedures were used. Thawed embryo transfer (TET) and other related procedures were surveyed. Results: Data from 36,990 ART procedures were provided by 74 clinics. Of the 30,410 cycles in which oocytes were retrieved, a complete transfer was performed in 91.0% (n=27,683). In addition, 9,197 cycles were confirmed to be clinical pregnancies in the FET cycles, representing a pregnancy rate of 30.2% per oocyte pick-up and 33.2% per ET. The most common number of embryos transferred in the FET procedures was three (38.1%), followed by two (34.7%) and one (14.3%). Of the 8,826 TET cycles, 3,137 clinical pregnancies (31.1%) were confirmed by ultrasonography. Conclusion: While the overall clinical pregnancy rate for the TET cycles performed was lower than the rate reported in 2010 (31.1% vs. 35.4%), the overall CPR for the FET cycles was higher than in 2010 (33.2% in 2011 and 32.9% in 2010). The most common number of embryos transferred in FET cycles was three, as was the case in 2010.

• 대한전자공학회논문지
• /
• 제27권12호
• /
• pp.1841-1851
• /
• 1990

Self-aligned gate GaAs MESFETs using ion beam deposited tungsten applicable to GaAs LSI fabrication process have been fabricated. Silicon implanted samples were annealed using isothermla two step RTA process and conventional one step RTA process. The electrical and physicla characteristics of annealed samples were investigated using Hall and I-V measurements. As results of measurements, activation characteristics of the isothermal two step RTA process are better than those of one step annealed ones. Using the developed processes, GaAs SAFETs (Self-Aligned Gate FET) have been fabricated and electdrical characteirstics are measured. As results, subthreshold currents of SAGFETs are 6x10**-10 A/\ulcorner, that is compatible to conventional MESFET, maximum transconductances of 0.75\ulcorner gate MESFET using one step RTA process and 2\ulcorner gate MESFET using isothermal two step RTA process are 18 mS/mm, 41 mS/mm respectively.

• Clinical and Experimental Reproductive Medicine
• /
• 제30권3호
• /
• pp.193-202
• /
• 2003

Objective: To evaluate the difference of implantation rate (IR) and clinical pregnancy rate (CPR) between two protocols of endometrial preperation in women undergoing frozen-thawed embryo transfer (FET) cycles. Methods: This study was performed during the different time periods: A retrospective study from January 2000 to June 2001 (phase I) and a prospective study from July 2001 to March 2002 (phase II). All the patients received estradiol valerate (6 mg p.o. daily) starting from day 1 or 2 of the menstrual cycle without pituitary down regulation. Progesterone was administered around day 14 after sonographic confirmation of endometrial thickness $\geq$7 mm and no growing follicle. In Group A (n=88, 99 cycles) of phase I, progesterone was administered i.m. at a dose of 50 mg daily from one day prior to thawing of pronuclear (PN) stage frozen embryo or three days prior to thawing of 6-8 cell stage frozen embryo and then each stage embryos were trasnsferred 2 days or 1 day later after thawing. In Group B (n=246, 299 cycles) of phase I, patients recieved progesterone 100 mg i.m. from one day earlier than group A; two days prior to PN embryo thawing, four days prior to of 6-8 cell embryo thawing. During the phase II, to exclude any differences in embryo transfer procedures, in Group 1 (n=23, 28 cycles) of phase II embryo was transfered by one who have used the progesterone protocol since the phase I. In Group 2 (n=122, 139 cycles) of phase II embryo was transfered by one who use the progesterone protocol from the phase II. Results: When compared across the phase and group, there were no significant differences in the characteristics. During the phase I, there were significant increase in IR (14.4% vs 5.9%, p=0.001) and CPR (28.3% vs 14.5%, p=0.000) in group A. During the phases II, IR (11.8% vs 10.6%) and CPR (27.6% vs 27.3%) show no differences between two groups. Conclusions: In FET cycles, IR and CPR are increased significantly by the change of dosage and timing of progesterone administraton. And the timing is considered to be more important factor because the dosage of progesterone did not affect implantation window in previous studies. Therefore, we suggest that progesterone administration in FET cycle should begin from one day prior to PN stage embryo thawing and three days prior to 6-8 cell stage embryo thawing.

• 전자공학회논문지D
• /
• 제36D권11호
• /
• pp.27-32
• /
• 1999

고온 열처리 시킨 $LiNbO_3/Si$(100) 구조를 이용한 MFS 디바이스를 제작하여 비휘발성 메모리 동작을 확인하였다. 제작한 트랜지스터의 선형영역에서 산출한 전계효과 이동도와 상호 컨덕턴스는 각각 약 $600cm^2/Vs$ 및 0.16mS/mm 이었다. 0.5V의 게이트 전압(즉, read 전압)에서 측정한 드레인 전류의 온/오프 비는 $10^4$배 이상이었다. 분극반전에 사용한 전압은 ${\pm}3V$ 이하로 매우 낮아 이는 저소비전력용 집적회로에 적용시키기에 기대가 된다. 세게 도핑시킨 반도체위에 제작한 MFS 커패시터는 500kHz의 바이폴라 전압펄스(peak-to-peak 6V, 50% duty cycle) 측정으로 $10^{10}$ cycle 까지도 분극의 열화현상이 없는 양호한 특성을 얻었다.