• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.7
• /
• pp.51-57
• /
• 1995

The theoretical analysis for AlInAs/GaInAs resonant tunneling diodes (RTDs), which have shown the improved negative differential resistance (NDR) characteristics, has scarcely been made in comparison with AlGaAS/GaAs RTDs. In this paper, the static current-voltage relation of Al$_{0.48}In_{0.52}As/Ga_{0.47}In_{0.53}$As RTDs were numerically estimated by using a self-consistent method. Assuming a simplified RTD with single quantum well structure and spacer layers, the peak current density (J$_{P}$) and the peak-to-valley current ratio (PVCR) were analysed as the function of the thickness of the well, the barrier and the spacer layer, and temperature. As the results, the peak current density and the peak-to-valley current ratio indicated a reciprocal relation roughly in respect to the thicknesses of the well and the barrier, and it was theoretically predicted that it be not attainable to provide a high peak current desity (J$_{P}$) over 1${\times}10^{5}A/cm^{2}$ as well as the large peak-to-valley current ratio (PVCR) over 10 that were the the critical conditions for the practical use.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.9
• /
• pp.718-726
• /
• 1998

J-E 특성 AC 임피더스 분석 그리고 주파수- 전도 특성들을 실험하여 임펄스 전류 서지가 ZnO 바리스터의 열화(degradation)에 미치는 영향을 고찰하였다. ZnO 바리스터 시편에 임펄스 전류(300A/$cm^24, 8/50$\mu s$)를 인가시킨 결과, 입계(grain boundary) 특성을 나타내는 비선형계수 $\alpha$와 E\ulcorner\ulcorner의 값은 크게 감소하였으나, 입자 특성을 나타내는 E_{100A}, E_{300A}$ 값에서는 큰 변화가 없었다. 이러한 열화 현상은 입계의 위치한 부성 전하 밀도, $N_s$의 감소에 한 쇼트키 장벽의 변화에 기인한 것으로 나타났다. 임펄스 서지에 의해 열화된 ZnO 바리스터는 AC 임피더스 분석에서 현저한 non-Debye 특성을 보이며, 이는 병렬 RC 네트워크로 모델링한 Cole-Cole 완화 관계식으로 입계의 열화 특성을 잘 설명할 수 있었다. 주파수-전도도 관계를 검토한 결과 Zno 바리스터는 호핑 전도(hopping conduction),\$sigma(\omega)\varpropto\omega^{\eta}$ 특성을 나타내면, 임펄스 서지가 인가된 이후 n 값이 감소하였다. 이는 임펄스 서지에 의해 입RP 결합 상태(defect states)가 호핑 전도가 발생하기 쉽고 다중(multiple)호핑에 의한 전도 메커니즘을 갖는 것으로 고찰되었다.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.7
• /
• pp.77-80
• /
• 2008

In this paper, low phase noise VCO using novel compact microstrip spiral resonator is proposed. A spiral resonator has super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff and a large coupling coefficient value, which makes a high Q value, and has reduced the phase noise. To increase the tuning range of VCO, varactor diode has been connected at the tunable negative resistance in VCO. This VCO has presented the oscillation frequency of $5.686{\sim}5.841GHz$, harmonics -29.83 dBc and phase noise of $-115.16{\sim}-115.17dBc/Hz$ at the offset frequency of 100 KHz.

• Journal of Satellite, Information and Communications
• /
• v.1 no.1
• /
• pp.54-58
• /
• 2006

A new design for easily controlling operating frequency of an antenna-integrated planar oscillator is introduced. The oscillator circuit of a broadband negative-resistance active part and a passive load including a patch antenna. The patch resonance is used for determining the oscillation frequency. This design reduces the possibility of mismatch between antenna radiation and oscillation frequencies. To achieve optimum output power, load-pull simulation for the negative-resistance circuit is used. The load-pull simulation shows the feed point and the delay of feed line can affect the oscillation power. Two negative-resistance circuits capable of supporting oscillation over full C-band and X-band are fabricated. The oscillation frequency, output power and phase noise for different patch antennas are measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.05a
• /
• pp.193-196
• /
• 2005

유기발광소자의 발광층의 두께에 따른 임피던스의 변화를 살펴보았다. 임피던스는 두께에 따라 저항의 변화에 따른 의존성을 보이며, 그에 따른 임피던스와 Cole-Cole 반원의 변화, 두께에 따른 $1/\tau$ 의 변화를 살펴보았다. 발광층의 두께는 각각 100, 200, 300 nm의 두께로 열증착하여 실험하였고, 소자의 구조는 $ITO/Alq_3/Al$의 구조로 측정 하였다. 유기발광소자의 발광층인 $Alq_3$의 두께가 증가함에 따라 임피던스의 크기가 증가하고, 위상각의 크기는 100nm의 경우 0V에서 용량성을 보이다가 6~10V까지 부성저항특성을 나타낸 후 약 22V에서 저항성을 나타내고, 200과 300 nm의 경우 12V까지 용량성을 나타내다 이후 22V 근방에서 $0^{\circ}$에 가까워지며 저항성을 나타내는 것을 알 수 있었다. 또한 두께에 따른 Cole-Cole 반원을 살펴보면 두께가 증가할수록 반원의 크기가 증가하는 것을 알 수 있으며, 이를 통해 간단한 등가회로를 예측할 수 있었다. 그리고 벌크내의 용량성$(C_p)$을 측정하여 두께의 증가에 따라 $C_p$ 값이 감소하는 것을 알 수 있었다.

• Journal of East-West Nursing Research
• /
• v.29 no.2
• /
• pp.117-128
• /
• 2023

Purpose: This study aims to develop a structural model for predicting motherhood in women with her first infant child and to contribute to the development of practical and specific nursing interventions to promote successful motherhood. Methods: The subjects of the study were 211 mothers and fathers who had their first child within 12 months and consented to the study. Data collected from June 2, 2022 to January 31, 2023 were analyzed using SPSS 28.0 and AMOS 26.0 programs. Results: The results of this analysis showed that maternal and paternal factors (postpartum depression and paternal attachment) and infantile factor (temperament) influenced the process of becoming a mother for a women with her first child, with postpartum depression being the most influential factor. Conclusion: In order to increase the level of motherhood, it is important to prevent postpartum depression and create a nurturing environment for mothers, and social system support and psychological nursing intervention strategies are necessary.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.1
• /
• pp.69-75
• /
• 2010

In this paper, with using the clapp type VCO(Voltage Controlled Osillator) configuration a wideband frequency synthesizer in UHF band is proposed. In order to design a wideband frequency synthesizer, the variation of phase in the negative resistance circuit as well as the load circuit was analyzed. Based on this result we propose a method to widen the operation range of the VCO. A frequency synthesizer using the proposed wideband VCO was designed and fabricated. It is shown that the synthesizer has the operating frequency range of 740~1,530 MHz by 0~5 V varactor tuning voltage, and it had the output power of 2~-6 dBm. Moreover, the phase noise measured as -77 dBc/Hz at 10 kHz offset, and as -108 dBc/Hz at 100 kHz offset from the oscillation frequency.

• Journal of Digital Convergence
• /
• v.15 no.10
• /
• pp.45-61
• /
• 2017

It is commonly accepted that fathers involve more in child rearing than ever given that dual earner families are increased in South Korea. Present study aims to emphasizes the significance of responsibility and examines the participation in childcare responsibility of fathers by performing survey. Responsibility is illustrated as paternal taking ultimate responsibility for child's welfare and care such as monitoring, planning, concerning, organizing, arranging and doing for childcare. Regarding the concept of responsibility, both twenty questions asking reasonability and twenty questions asking non-responsibility are included in the questionnaire. As a result of statistical analyses, present study shows that fathers are less likely to participate in those twenty items of childcare responsibility, compared to twenty items of childcare non-responsibility. Implications are also provided. Responsibility of paternal involvement particularly needs to be addressed in the sense that childcare has contributed to pertaining inequality for women in both the workplace and domestic life.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.8
• /
• pp.45-51
• /
• 2007

We designed and fabricated the planar graded-gap injector GaAs Gm diodes with $1.6{\mu}m$ active length for operation at 94 GHz. The fabrication of the Gunn diode is based on MESA etching, Ohmic metalization, and overlay metalization. The measured negative resistance characteristics of the graded-gap injector GaAs Gunn diodes are examined for two different device structures changing the distance between the cathode and the anode electrodes. Also, we discuss the DC results under the forward and the reverse biases concerning the role of the graded-gap injector. It is shown that the structure having the shorter distance between the cathode and the anode electrode has higher peak current, higher breakdown voltage, and lower threshold voltage than those of the larger distance.

• Korean Journal of Social Welfare
• /
• v.69 no.1
• /
• pp.199-222
• /
• 2017

This study examined the parental experiences of the fathers who reared their children with brain lesions. Since a brain lesion is considered a lifelong disability, children with brain lesions need the medical and social management through their entire life. Due to the lack of specialized caring services and organizations in Korea for such children, their families are forced to take care of them. For this reason, it is necessary to study about the fathers who are rearing the children with brain lesions. For this purpose, four fathers had participated in this study and data were collected through one to one in-depth interviews. Using Giorgi(2004)'s phenomenological research method, the study results were as follows. The substantial themes were "charred heart", "surviving the hardships", "the ruins of life", "attitude against reality", "the unique composition of family life", "children as fate", "father's love." Based on the these analysis results, the implications were suggested to cure the psychological and institutional difficulties and to provide supportive services for the fathers and families who care the children with brain lesions.