• Clinical and Experimental Reproductive Medicine
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• 제20권1호
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• pp.79-85
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• 1993

Five hundred and fory-four women were provided government funded sterilization reversal services with technique of microsurgery at 15 reversal institutions designated by the Korean Association for Voluntary Sterilization since the inception of Female Reversal Program in 1981. A large majority of reasons for requesting reversal surgery was a loss of children, comprising 87.3%, and the mean interval between sterilization and reversal was 33.6 months. Two hundred and ninty-one of 418 women who were post-operatively followed up with the length of 11 months to 11 years, have experienced term dilivery or ,intra-uterine pregnancy, represented 69.6%. Eight cases have experienced ectopic pregnancy and 9 cases spontaneous abortion. The largest number of reversal clients were sterilized by the laparoscopic unipolar coagulation technique and the next largest group was sterilized by the laparoscopic banding technique, representing 59.8% and 28.9% respectively. The highest pregnancy rate, 80.9%, was shown in clients who had undergone laparoscopic banding technique while the lowest, 61.8%, was the group of laparoscopic bipolar coagulation. The most common site of the anastomosis was isthmic-ampullary portion and the next was isthmic-isthmic portion. The highest success rate, 77.8 %, was marked in the isthmic-isthmic anastomosis and the lowest was in the ampullary-ampullary anastomosis, representing 50.0%. A more than 60% of the clients became pregnant within 6 months of their reversal surgery, with the shortest interval being 1 month, the longest 39 months, and the mean 7.6 months. A large majority of the successful cases were pregnancy within 1 year of their reversal surgery, representing 82.1 %. The higher rate of pregnancy, 73.5%, was in the clients undergone reversal surgery within 36 months of their sterilization and the lower pregnancy rate, 64.1 %, was in the clients undergone reversal surgery longer than 37 months of their sterilization.

• 한국표면공학회지
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• 제44권2호
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• pp.60-67
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• 2011

Ternary B-C-N coatings were deposited on Si(100) wafer substrate from $B_4C$ target by RF magnetron sputtering technique in $Ar+N_2+CH_4$ gas mixture. In this work, the effect of reactant gas ratio, $CH_4/(N_2+CH_4)$ on the composition, kinds and amounts of bonding states comprising B-C-N coatings were investigated using two different bias power sources of continuous and unipolar DCs. In addition, the tribological properties of coatings were studied with the composition and bonding state of coating. It was found that the substrate bias power had an effect on chemical composition, and all of the obtained coatings were nearly amorphous. Main bonding states of coatings were revealed from FTIR analyses to be h-BN, C-C, C-N, and B-C. The amount of C-C bonging mainly increased with increase of the reactant gas ratio. From our studies, both C-C and h-BN bonding states improved the tribological properties but B-C one was found to be harmful on those. The best coating from tribological points of view was found to be $BC_{1.9}N_{2.3}$ composition.

• 대한기계학회논문집B
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• 제35권10호
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• pp.1013-1018
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• 2011

전기집진에서의 10 nm 급 초미세 나노입자의 하전 및 집진 특성을 파악하였고, 나노입자의 확산효과와 비교해 보았다. 나노입자의 하전율과 확산손실 효과의 지배력에 따라 전기집진기에서의 나노입자 집진효율이 결정되는 것을 확인할 수 있었다. 10nm 급 영역에서는 입자 크기가 작아질수록 지속적으로 집진효율이 감소하였다. 10 nm 이하의 영역에서는 나노입자의 부분적 하전효과가 전기집진기 내의 확산 손실 효과보다 지배적인 것을 알 수 있었다. 10 nm 이하의 나노입자에 대하여 집진효율 실험 결과가 단극 확산 하전 이론을 적용한 입자하전율 계산 결과와도 잘 일치하였다.

• 한국지능시스템학회논문지
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• 제22권3호
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• pp.367-372
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• 2012

본 논문은 아날로그형 자기위치 장치(magnetic positioning system)의 개발과 퍼지 추론 시스템(FIS: fuzzy inference system)을 통한 정밀도 향상에 관한 것이다. 자기위치 장치는 무인운반차(AGV: automatic guided vehicle)의 자기-자이로 유도장치(magnet-gyro guidance system)에 사용되는 장치로, 바닥에 매설된 자석의 위치를 계측하는 장치이다. 기존의 판매되고 있는 자기-자이로 유도 장치는 외국에서 독점 판매되고 있어, 국내에서는 가격이 매우 비싸다. 또한, 자기위치 장치에 디지털 타입의 단극성 홀센서를 이용하기 때문에 위치측정 정밀도가 낮다. 이에, 본 논문에서는 자기위치 장치를 직접 개발하였고 퍼지 추론 시스템을 통해 자기위치 장치의 정밀도 향상시켰다. 실험은 직접 개발한 아날로그형 자기위치 장치를 이용하였으며, 기존의 위치측정 방법과 제안된 방법의 성능을 비교하였다. 실험 결과, 제안된 방법이 자기위치 장치의 정밀도를 향상시킴을 확인하였다.

• 한국통신학회논문지
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• 제28권4B호
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• pp.245-256
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• 2003

2-D OCDMA는 근거리 광통신망의 구현을 위한 유력한 기술적 해법으로 고려되고 있으며, 다양한 2-D OCMA 기법/기술에 대한 많은 연구가 이루어지고 있다. 본 논문에서는 단극부호를 사용하는 2D OCDA 통신망의 성능분석을 위한 새로운 다중접속 간섭모델을 제안하고 이 간섭모델을 기초로 하는 최대공산검출기를 유도한다. 또한, 이들 최대공산검출기와 기존에 제안된 보다 단순한 구조를 갖는 검출기의 검출성능을 컴퓨터 모의실험을 통해 비교한다. 상대적으로 복잡한 연산이 어려운 순수 광통신망에서의 적용을 고려하여 각 검출기의 구현복잡도를 평가하고, 그 결과 Pulse-Binomial 모델과 Pulse-Poisson 모델로부터 유도된 최대공산 검출기와 AND 검출기가 검출성능과 구현용이성측면에서 최적균형점에 있음을 확인한다.

• Transactions on Electrical and Electronic Materials
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• 제15권1호
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• pp.24-27
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• 2014

In this study, the effects of Mn-doping and the electrode materials on the memory characteristics of $ZnO_xS_{1-x}$ resistive random access memory (ReRAM) devices on plastic are investigated. Compared with the undoped Al/$ZnO_xS_{1-x}$/Au and Al/$ZnO_xS_{1-x}$/Cu devices, the Mn-doped ones show a relatively higher ratio of the high resistance state (HRS) to low resistance state (LRS), and narrower resistance distributions in both states. For the $ZnO_xS_{1-x}$ devices with bottom electrodes of Cu, more stable conducting filament paths are formed near these electrodes, due to the relatively higher affinity of copper to sulfur, compared with the devices with bottom electrodes of Au, so that the distributions of the set and reset voltages get narrower. For the Al/$ZnO_xS_{1-x}$/Cu device, the ratio of the HRS to LRS is above $10^6$, and the memory characteristics are maintained for $10^4$ sec, which values are comparable to those of ReRAM devices on Si or glass substrates.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.37.5-38
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• 2010

경희대학교 우주탐사학과에서는 우주공간 탐사를 위해 Trio(TRiplet Ionospheric Observatory)-CINEMA(Cubesat for Ions, Neutrals, Electrons and MAgnetic fields)로 명명된 초소형 위성을 개발하고 있다. 과학임무는 지구 저궤도에서 고에너지 입자를 관측하는 것이며, 이를 위해 고에너지 (2~300keV) 입자 검출기와 자기장 측정기가 탑재된다. 저에너지 입자 검출기 시스템인 STEIN(SupraThermal Electrons, Ions, Neutrals)은 $1\times4$ Array의 개선된 실리콘 검출기와 이온, 전자, 중성입자를 분리할 수 있는 정전장 편향기, 그리고 신호를 처리하는 전자회로로 구성되어있다. 설계된 전자회로는 매우 작은 검출기 기판, 아날로그 기판과 디지털 기판으로 이루어져 있고, 475mW 이하의 저 전력으로 동작한다. 또한 2~100keV의 에너지를 1keV이하의 해상도로 30,000event/sec/pixel 까지 관측 할 수 있도록 회로를 설계하였다. 센서로 들어온 입자로 인해 발생한 펄스의 신호는 4개의 아날로그 회로가 담당하게 되는데, Folded cascode amplifier를 배치하여 증폭률을 높인 Charge sensitive amplifier를 통해 신호를 증폭하고, $2{\mu}s$ unipolar gaussian shaping amplifier를 통해 읽기 쉽게 처리된 신호를 상한파고선별기와 하한파고 선별기를 통해 유효 값 여부를 판단하고, 피크 검출기를 통해 피크의 타이밍을 측정한 뒤 신호를 아날로그-디지털 변환 회로를 통하여 8bit의 값으로 나타내어, 입자들의 Spectrum을 측정하게 된다. 크기와 소비전력이 적음에도 검출성능이 우수하기 때문에 이 시스템은 향후 우주탐사 시스템에 있어 매우 중요한 역할을 수행 할 것으로 생각한다.

• 한국소음진동공학회논문집
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• 제17권3호
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• pp.241-248
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• 2007

A study has been conducted to investigate the subjective responses of loudness and annoyance according to the exposed time of urban traffic noise in controlled laboratory environment. To make a closer inspection into psychological response relevant to noise characteristics while varying the time of exposure to noise, the subjects were presented a set of noises with different exposed time and requested to judge spontaneously on a 100-unipolar scale. To be concrete, the subjects were exposed to noises being varied in time from 15 sec up to max. 1,200 sec for the controlled traffic noise sources. So far achieved from laborious tests, it has an importance being on the logarithmic relations of perceived loudness and exposed time, say, it is more increased the perceived loudness in the sorter exposed time than in the longer exposed time. However, the trend is said to be not effective for the case of annoyance. On the other hand, the subjective impressions on relative annoyance of noise is shown to be correlated with the noise characteristics such as loudness (sones), tonality and time with logarithmic scale, the product correlation moment being calculated as $R^{2}=0.99$. The variances to be explained for annoyance assessments through varying the time of exposure were ranged between 30 % and 50% for the exposed time, $27{\sim}37%$ for tonality, and $34{\sim}20%$ for loudness, respectively With these results, hopefully, it can be helpful for those who want to work out an experimental design for evaluating an environmental noise or to quantify any psychological dimensions found in annoyance assessments.

• 한국전자통신학회논문지
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• 제16권4호
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• pp.763-770
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• 2021

본 논문에서는 ISM 대역에서 동작하는 BAN(Body Area Network) 신호의 영향을 배제하기 위해서 4.567 GHz에서 작동하는 온 바디 마이크로스트립 패치 안테나의 설계 및 최적화 과정을 제시하였다. 하지 해면골 골다공증 감시를 위한 이 안테나는 향상된 반사손실 및 대역폭을 가지면서, 경박단소하도록 설계하였다. 적용된 하지 주변 구조는 5층 유전체 평면으로 구조화 하였으며, 손실을 고려한 각층의 복소유전상수는 다중 Cole-Cole 모델 매개변수를 사용하여 계산하였으나, 정상 및 골다공증 해면골은 단극형 모델을 사용하였다. 팬텀상 동축급전 안테나의 반사손실은 4.567 GHz에서 -67.26 dB이고, 골다공증 경우 동일 주파수에서 반사손실차 𝚫S₁₁=35.88 dB이고, 공진 주파수 차는 약 7 MHz이다.

• The Korean Journal of Pain
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• 제35권1호
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• pp.114-123
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• 2022

Background: Different views have been proposed on the radiofrequency treatment modes and parameters of radiofrequency thermocoagulation of the spinal dorsal root ganglion for the treatment of postherpetic neuralgia (PHN). It is urgent to identify a more effective therapy for patients with PHN. Methods: Patients who underwent radiofrequency thermocoagulation therapy for PHN were retrospectively reviewed and were divided into a radiofrequency thermocoagulation (CRF) and double neddles radiofrequency thermocoagulation (DCRF). The pain scores (numerical rating scale, NRS) were evaluated at the following time points: before the operation, 1 day, 3 months, 6 months, 1 year, and 2 years after operation. The incidence of complications and the degree of pain relief were evaluated. The in vitro ovalbumin experiment was used to indicate the effects of radiofrequency thermocoagulation. Results: Compared with the preoperative NRS scores, the postoperative NRS scores decreased significantly; the NRS scores of the DCRF group was lower than that of the CRF group at all time points from 6 months to 2 years following the operation. The total effective rate of the DCRF group was significantly higher than that of the CRF group at 2 years following the operation. The incidence of numbness in the DCRF group was higher than that noted in the CRF group. The ovalbumin experiments in vitro indicated that the effects of radiofrequency thermocoagulation were optimal when the distance between the two needles was 5 mm. Conclusions: DCRF with a 5 mm spacing exhibits a longer duration and higher effective rate in the treatment of PHN and is worth promoting.