• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1289-1291
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• 1994

Dielectric properties of $C_{22}$-Quinolium(TCNQ) Langmuir-Blodgett (LB) films were studied as a function of frequency(10Hz-13MHz) and annealing temperature($20{\sim}240^{\circ}C$). A complex dielectric constant ${\epsilon}^*={\epsilon}'-i{\epsilon}"$, in general, shows the frequency dependence of orientational polarization in the measured frequency range. A dielectric permittivity ${\epsilon}'$ at 10Hz is around 8.2 and decreases very slowly as the frequency increases up to 1 MHz, and then suddenly drops above this frequency, while a dielectric loss factor ${\epsilon}"$ reaches a maximum near 1 MHz. Its annealing temperature dependence at 10Hz shows that ${\epsilon}'$ and ${\epsilon}"$ increase as the temperature increases upto $180^{\circ}C$, even though there is a little drop near $120{\sim}160^{\circ}C$. Both ${\epsilon}'$ and ${\epsilon}"$ drop quickly above $180^{\circ}C$. which may be thought of a destruction of the LB films. Another fact of the annealing temperature dependence of the dielectric constant is an occurrence of the new dielectric dispersion below 100Hz. This low frequency dispersion is getting clear above $80^{\circ}C$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.2
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• pp.1-4
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• 1976

In this paper, temperature dependence of the resonant frequency of thickness shear mode in X cut plate of $LiN_bO_3$ is theoretically analyzed. An a result of this analysis, theoretical value -78.43${\times}10^{-5}/^{\circ}C$ of the temperature coefficient of resonant frequency is obtained.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.19-22
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• 2001

This paper proposes a double cantilever sandwich-beam method for evaluating the frequency dependence of material dynamic characteristics. The flexural vibration of a double cantilever sandwich-beam specimen with a partially inserted rubber layer was studied using a finite element simulation in combination with the sine-sweep test. Quadratic relationships of dynamic elastic modulus and material loss factor of rubbers with frequency were quantitatively suggested employing the least square error method.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1108-1111
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• 2007

OLED driving voltage shift can reduce the OLED display lifetime, especially for digitally driven AMOLED. By operating OLED at high frequency, we were able to suppress OLED voltage shift degradation, expecting improved AMOLED lifetime. We describe frequency dependence of voltage shift obtained from bias stress test of OLED.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.186-188
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• 1988

Relaxation spectra of the linear dielectric constants $\varepsilon=\varepsilon'-j{\varepsilon}"$ have been measured as functions of temperature and frequency for alternating copolymers of vinylidene cyanide (VDCN/VAc, VDCN/VPr, VDCN/VBz and VDCN/St) It is found that the linear dielectric constants e show characteristics of the temperature dependence that the real part have a large peak related to the glass transition point(Tg), and of the frequency dependence that the real port increases with decreasing frequency and the imaginary part increases largely in low frequency range. These phenomena mean Debye-type relaxation due to the micro-Brownian moi ions of non-crystalline seqments.

• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.375-379
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• 2008

Redox behavior was observed in alkali alkaline earth silicate PDP (Plasma Display Panel) glass melts doped with sulfate and sulfide by square wave voltammetry (SWV). According to voltammograms produced at a temperature range of 1100 to $1400^{\circ}C$ and frequency range of 5 to 1000 Hz, both melts showed the same behavior in which there is one reduction peak at low frequency but another peak at an increase of frequency. Based on the frequency dependence of the peak current, self diffusivity of $S^{4+}$ was determined. Based on the temperature dependence of the peak potential, standard enthalpy (${\Delta}H^0$) and standard entropy (${\Delta}S^0$) for the reduction of $S^{4+}$ to $S^0$ were calculated.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.35-42
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• 2002

Modulation frequency dependences of the pyroelectric properties of PLT (P $b_{1-x}$ L $a_{x}$ $Ti_{1-x}$ 4/ $O_3$) thin films with La concentrations of 5, 10 and 15㏖% have been investigated by using the dynamic method. The PLT thin film with 10㏖% of the La concentration (PLT(10) thin film) shows the most excellent pyroelectric properties among the films. For PLT(10) thin film, the pyroelectric coefficient shows the maximum value of 6.6$\times$10$^{-9}$ C/$\textrm{cm}^2$ㆍK without frequency dependence. The figure of merits for the voltage responsivity and specific detectivity are 1.03$\times$10$^{-11}$ Cㆍcm/J and 1.46$\times$10$^{-9}$ Cㆍcm/J, respectively. Voltage responsivity corresponding to the pyroelectric voltage is almost constant at low modulation frequency and decreases in proportional to frequency at high modulation frequency. Voltage responsivity is 5.15 V/W at 8Hz. Noise equivalent power (NEP) and specific detectivity ( $D^{*}$) of the PLT(10) thin film are 9.93$\times$10$^{-8}$ W/H $z^{1}$2/ and 1.81$\times$10$^{6}$ cmH $z^{1}$2/W at the frequency of 100Hz, respectively. The results indicate that PLT(10) thin film is very suitable for pyroelectric IR sensors.s.s.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.579-582
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• 2013

Background: In this study our aim was to determine the rate of smoking in a sample of psychiatric in-patients with diagnoses of schizophrenia, bipolar disorder and major depression and to examine factors related to smoking status and the level of dependence in this population. Materials and Methods: A total of 160 people were included in this descriptive study. 80 were inpatients with schizophrenia, bipolar disorder and major depression and 80 people without any psychiatric diagnoses were included as a control group. The participants were interviewed face-to face using a semi-structured questionnaire and Fagerstrom Test for Nicotine Dependence was used to define smoking habits. Results: The mean age of the participants was $37.24{\pm}12.19$ years ranging from 18 to 81 years, 54.4% of the participants were (n=87) female, and 45.6% cases (n=73) were male. 70% (n=56) of the patients and 55% of the control group were smoking and the difference was statistically significant (p<0.01). Total score of Fagerstrom Test for Nicotine Dependence in the patient group was statistically significantly higher than in the control group (p<0.01). Conclusions: In our sample, the frequency of cigarette smoking and nicotine dependence among psychiatric inpatients was high, posing a high risk for smoking related diseases including cancers; therefore there should be counseling on tobacco control and smoking cessation programming targeting this population.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.7-7
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• 2010

The SBN thin films were deposited at substrate temperature of 300[$^{\circ}C$] on Pt-coated electrode (Pt/Ti/$SiO_2$/Si(100)) using RF sputtering method. The grain and crystallinity of SBN thin films were increased with the increase of annealing temperature. The dielectric constant(150) of SBN thin film was obtained by annealing temperature above 750[$^{\circ}C$]. The frequency dependence of dielectric loss showed a value within 0.03 in frequency ranges of 1~1000[kHz].

• Composites Research
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• v.14 no.3
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• pp.69-76
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• 2001

This paper proposes a double cantilever sandwich-beam method fur evaluating the frequency dependence of dynamic characteristics of rubbers. The flexural vibration of a double cantilever sandwich-beam specimen with an inserted rubber layer was studied using a finite element simulation in combination with the sine-sweep test. Quadratic relationships of dynamic elastic modulus and material loss factor of rubbers with frequency were suggested employing the least square error method.