• Journal of Chest Surgery
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• 제25권4호
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• pp.364-382
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• 1992

In order to investigate the effect of intracellular cyclic GMP on the calcium channel, whole cell patch clamp technique with internal perfusion method was used in the single ventricular myocytes of the rabbit. Cyclic GMP, cGMP analogues, cAMP, isopernaline and forskolin were perfused into cells and their effects on the calcium current were analysed by applying depolarizing step pulse of 10 mV in amplitude for 200 msec from holding potential of -40 mV. Calcium currents usually activated from -30 mV and then reached a peak at +10 mV. Amplitude of the calcium current was standardized with membrane capacitance, 50 pF. Peak amplitude at +10 mV in control was -0.15 nA/50pF. When 100 mM cAMP was applied from the pipette, peak amplitude of calcium current increased to -0.32 nA and addition of 1 mM isoprenaline further increased its amplitude. In the presence of cGMP it alone also produced an increase of the calcium current to -0.52 nA/50pF and addition of isoprenaline or forskolin increased its magnitude to -[0.55~0.95] nA/50pF. Simultaneous application of cGMP and cAMP increased the calcium current to -0.67 nA/50pF. Among the cGMP analogues, 8-Br-cGMP was the most potent stimulant for the calcium current activation. From the above results it could be concluded tlat cGMP increases the calcium current not through cAMP dependent protein kinase nor cAMP dependent phosphodiesterase pathway, but through independent phosphorylation pathway, possibly cGMP dependent protein kinase pathway.

• Journal of Power Electronics
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• 제7권3호
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• pp.213-221
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• 2007

A digital state feedback control method for the current mode control of DC-DC converters is proposed in this paper. This approach can precisely achieve interleaved current sharing among the converter modules. As the controller design and system analysis are performed in the time domain, the proposed method can easily satisfy the required converter specification by using the pole placement technique. The digital state feedback controller in the continuous and discrete time domain is derived for the robust tracking control. For the verification of the proposed control scheme, a parallel module bi-directional converter in a prototype 42V/14V hybrid automotive power system, which is a design example in the continuous time domain, and a parallel module buck converter, which is a design example in the discrete time domain, are implemented using a TMS320F2812 digital signal processor (DSP).

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.159-162
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• 2000

유가식배양을 통한 고농도배양에서 계면활성제와 산소전달물질의 첨가는 세포의 고밀도와 배지의 고점도로 인해 발생하는 nutrient의 물질전달제한과 산소부족현상을 효과적으로 해결하였다. Pluronic 10R-5는 Pluronic F-68과 같은 triblock copolymer 구조이며 세포생장의 저해를 나타내지 않았다. 그러나 diblock copolymer구조이며 소수성 부분이 hydrocarbon block인 Plurafac A-38은 세포의 생장을 저해함을 관찰할 수 있었다. 따라서 장기간의 유가식배양이나 perfusion 배양을 수행할 경우 세포의 생존도를 증대시켜 유용물질의 생산성을 높일 수 있으며 여러 형태의 bioreactor에서 고농도 배양을 가능케 하여 유용물질 생산성을 높일수 있을 것이라고 기대된다.

• 말소리와 음성과학
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• 제5권4호
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• pp.71-78
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• 2013

The purpose of this study was to compare the acoustic voice outcomes of children with cochlear implant to those of children with normal hearing. Participants were 41 children using unilateral cochlear implant (18 males and 23 females), and children with normal hearing from the same age and sex. Mean age of implantation was approximately 3 years old, mean duration of implant use was 4 years in CI group. Acoustic analyses were performed using MDVP of CSL. Speech samples were 3 sustained vowels, /a, i, u/. 9 parameters (F0, Fhi, Flo, Jitter, Shimmer, vF0, vAm, NHR, and SPI) were analyzed. Children with CI did not show the significant differences in those parameters after the vowel /a/ phonation. Meanwhile, there were significantly different results in F0, Fhi, vF0, and SPI after /i, u/ phonation. These results revealed that differences of voice characteristics in children with CI compare to children with NH persist regarding vowel context. It suggests that high vowels would recommend as speech samples for acoustic evaluation. Futhermore perceptual analysis and speech therapy for phonation control would be necessary for children with CI.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.335-335
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• 2014

Over the past several years, transparent conducting oxides have been extensively studied in order to replace indium tin oxide (ITO). Here we report on fluorine doped zinc tin oxide (FZTO) films deposited on glass substrates by radio-frequency (RF) magnetron sputtering using a 30 wt% ZnO with 70 wt% SnO2 ceramic targets. The F-doping was carried out by introducing a mixed gas of pure Ar, CF4, and O2 forming gas into the sputtering chamber while sputtering ZTO target. Annealing temperature affects the structural, electrical and optical properties of FZTO thin films. All the as-deposited FZTO films grown at room temperature are found to be amorphous because of the immiscibility of SnO2 and ZnO. Even after the as-deposited FZTO films were annealed from $300{\sim}500^{\circ}C$, there were no significant changes. However, when the sample is annealed temperature up to $600^{\circ}C$, two distinct diffraction peaks appear in XRD spectra at $2{\Theta}=34.0^{\circ}$ and $52.02^{\circ}$, respectively, which correspond to the (101) and (211) planes of rutile phase SnO2. FZTO thin film annealed at $600^{\circ}C$ resulted in decrease of resistivity $5.47{\times}10^{-3}{\Omega}cm$, carrier concentration ~1019 cm-3, mobility~20 cm2 V-1s-1 and increase of optical band gap from 3.41 to 3.60 eV with increasing the annealing temperatures and well explained by Burstein-Moss effect. Change of work function with the annealing temperature was obtained by ultraviolet photoemission spectroscopy. The increase of annealing temperature leads to increase of work function from ${\phi}=3.80eV$ (as-deposited FZTO) to ${\phi}=4.10eV$ ($600^{\circ}C$ annealed FZTO) which are quite smaller than 4.62 eV for Al-ZnO and 4.74 eV for SnO2. Through X-ray photoelectron spectroscopy, incorporation of F atoms was found at around the binding energy of 684.28 eV in the as-deposited and annealed FZTO up to 400oC, but can't be observed in the annealed FZTO at 500oC. This result indicates that F atoms in FZTO films are loosely bound or probably located in the interstitial sites instead of substitutional sites and thus easily diffused into the vacuum from the films by thermal annealing. The optical transmittance of FZTO films was higher than 80% in all specimens and 2-3% higher than ZTO films. FZTO is a possible potential transparent conducting oxide (TCO) alternative for application in optoelectronics.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.681-684
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• 2001

농작물 종자의 발아를 억제하는 미생물, Pseudomonas sp. F721을 자연계로부터 분리 및 동정하였다. 그리고 식물성장 호르몬에 의하여 발아억제물질이 유도되어 생산됨이 밝혀졌다. 분리된 균주의 최적 배양조건을 검토한 결과, $35^{\circ}C$, pH 9.0, 15Orpm, 48 hr, substrate 0.5% (w/v), strain 1.0% (v/v)이었다. 발아억제의 정도는 종자의 종류에 따라 차이가 있었다. 발아억제물질의 물리${\cdot}$화학적 안정성 검토결과 pH 2.0${\sim}$12.0, $-20{\sim}100^{\circ}C$에서 대하여 안정성을 가지고 있었다. 발아억제 물질은 발아 초기에 대조 시험보다 약 90% 이상 발아를 억제하였다.

• ETRI Journal
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• 제31권6호
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• pp.755-764
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• 2009

This paper presents a switched self-biasing and a tail current-shaping technique to suppress the 1/f noise from a tail current source in differential cross-coupled inductance-capacitance (LC) voltage-controlled oscillators (VCOs). The proposed LC VCO has an amplitude control characteristic due to the creation of negative feedback for the oscillation waveform amplitude. It is fabricated using a 0.13 ${\mu}m$ CMOS process. The measured phase noise is -117 dBc/Hz at a 1 MHz offset from a 4.85 GHz carrier frequency, while it draws 6.5 mA from a 0.6 V supply voltage. For frequency tuning, process variation, and temperature change, the amplitude change rate of the oscillation waveform in the proposed VCO is 2.1 to 3.2 times smaller than that of an existing VCO with a fixed bias. The measured amplitude change rate of the oscillation waveform for frequency tuning from 4.55 GHz to 5.04 GHz is 131 pV/Hz.

• 한국정밀공학회지
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• 제14권10호
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• pp.15-27
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• 1997

Quasti-static cutting force variations in milling process are measured indirectly using spindle motor current. Quasi-static sensitivity of the spindle motor current is higher than that of the feed motor current. Magnitude of the spindle motor current is independent of cutting direction. The linear relationship between the cutting force and the spimdle motor RMS current at various spindle rotational speed is obtained. Frequency/ Voltage(F/V) converter voltage is measured to identify the spindle speed and to determine the cutting force at various spindle speeds. Overload on the tool during milling process can be detected using the proposed indirect cutting force measurement. Based on these measurements, cutting force is regulated at a constant level by feedrate control.

• 한국치위생학회지
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• 제1권1호
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• pp.125-132
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• 2001

This study was carried out to investigate the effect of multi or single application of fluoride plus 0.05% NaF solution on the remineralization of dental caries lesion. The microhardness changes of enamel surface were measured after application of fluoride and precipitation of 0.05% NaF solution on 6 groups of cow's tooth on which the artificial carious lesions were formed first. Test groups were calssified into two step application with NaF, $SnF_2$ and APF under different application time conditions plus 0.05% NaF solution(group I, II, III, IV) and single application with APF plus 0.05% NaF solution (group V) and control(0.05% NaF solution only, group IV). The obtained results were as follows. 1. Regarding microhardness change of enamel surface. microhardness increments in group I(NaF for 1 minute+APF for 3 minutes+0.05% NaF solution for 1 minute), II($SnF_2$ 1 min+APF 3 min+NaF sol.), III($SnF_2$ 2 min+APF 2 min+NaF sol.), IV(NaF 2 min+APF 2 min+NaF sol.) and V(APF 4 min+NaF sol.) were significantly greater than group VI.(P<0.05) 2. Microhardness changes of shorter application time of $SnF_2$ (group II) were significantly greater than group III. (P<0.05) 3. Microhardness changes were variable with kinds of fluoride, application sequence and application time of fluoride. but had no relation with the number of fluoride application.

• 한국응용곤충학회지
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• 제23권2호
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• pp.74-81
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• 1984

딸기${\cdot}$시들음병의 발생분포, 병원균의 몇가지 성질, 방제효과 및 품종 저항성에 대하여 조사한 결과를 요약하면 다음과 같다. 1. 본병은 수년 전 경남의 삼낭진, 김해 지역에서 발견된 이후 발생지역이 급속히 확대되어 현재 우리나라 딸기재배 전 지역에 발생되고 있으며 그 피해도 격심하다. 2. 본 분리균은 V-8 Agar상에서 대형, 소형분생포자와 후막포자가 형성되었고 단포의 소형분생포자는 무격막의 분생자병의 선단에 의두상으로 형성되어 F. oxysorum에 속하였다. 3. 본 균의 대형분생포자 형성은 균주와 재배종류에 따라 차이가 심하였으나 균주 모두 V-8 Agar에서 풍부히 형성되었고 PDA, PSA와 Malt extract Agar 에서는 극히 불량하였다. 4. F. oxysporum의 분화형이 다른 f. sp. curumerinum, f. sp. melonsis, f. sp lycopersici, f sp. lini, f. sp. fragariae 및 본 균을 공시하여 오이, 토마토, 참외 , 수박, 수세미 , 양배추, 말기에 cross inoculation 시험결과 각 분화형은 각자의 기주에만 병원성을 나타내었고 본 균은 딸기 만을 침해하였으며 본 균과 f.sp. fragariae의 2균주와의 형태, 기생성 및 병징 등에서 거의 일치되었으므로 본 균의 분화형은 Fusarium oxysporum Schl. f sp. fragariae Winks & Williams로 동정되었다. 5. 본 균의 균계생육과 포자형성 저지효과에 있어서 Benomyl과 Homai가 가장 우수하였으나 Homai에 의한 포자형성 저지효과가 Benomyl 보다 높은 경향이었다. 6. 접종에 의한 품종 저항성 검정결과, 구류미 38, Himiko, Senga gigana 및 Daehak 1은 저항성이었고, 보교조생, Instiate Z-4, Juspa, Puget beauty 및 Marshall 은 감수성이었다.