• Journal of Biomedical Engineering Research
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• v.20 no.4
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• pp.461-469
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• 1999

In this paper, an ECG-NIBP patient monitor is designed. This is an essential equipment to measure and monitor patient's physical condition - electrocardiogram(ECG) wave, heart rate(HR), and noninvasive blood pressure(NIBP) - in ICU, CCU, and operating room. The ECG is an electrical waveform produced by relaxation and contraction of the cardiac muscle. Most physicians diagnose patient's cardiac states from ECG pattern. A blood pressure is one of the clinical indexes measured in a emergency room or operating room. In this paper, the blood pressure is measured in artery by using the nonivasive oscillometric method. The developed patient monitor was inspected and compared with other instruments in operating rooms. The results were 1bpm of maximum difference in the heart rate, 15mmHg in the systolic pressure, 16mmHg in the diastolic pressure, and 25mmHg in the mean blood pressure. But the total results were 0.15bpm of the mean difference in the heart rate, 5mmHg in the systolic pressure, 10mmHg in the diastolic pressure, and 9mmHg in the mean blood pressure. The designed ECG-NIBP patient monitor can measure the ECG wave, HR, and BP. And the multi-tasking module of pulse oximetry . respiration . temperature monitor will be added in the near future.

• Journal of the Korean Magnetics Society
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• v.19 no.2
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• pp.57-61
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• 2009

$MnFe_2O_4$ nanoparticles have been prepared by a sol-gel method. The structural and magnetic properties have been investigated by XRD, SEM, and $M{\ddot{o}}ssbauer$ spectroscopy, VSM. $MnFe_2O_4$ powder that was annealed at $250^{\circ}C$ has spinel structure and behaved superparamagnetically at room temperature. $MnFe_2O_4$ annealed at 400 and $500^{\circ}C$ has a typical spinel structure and is ferrimagnetic in nature. The estimated size of superparammagnetic $MnFe_2O_4$ nanoparticle is around 17 nm. The hyperfine fields of the A and B patterns at 4.2 K were found to be 508 and 475 kOe, respectively. The blocking temperature ($T_B$) of superparammagnetic $MnFe_2O_4$ nanoparticle is about 120 K. The magnetic anisotropy constant and relaxation time constant of $MnFe_2O_4$ nanoparticle were calculated to be $4.9{\times}10^5erg/cm^3$.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.6
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• pp.64-72
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• 2010

In general, due to the interactions among subsystems, it is difficult to design an decentralized controller for nonlinear interconnected systems. In this study, the model of nonlinear interconnected systems is studied via decentralized fuzzy control method with time delay and polytopic uncertainty. First, the nonlinear interconnected system is represented by an equivalent Takagi-Sugeno type fuzzy model. And the represented model can be rewritten as Parameterized Linear Matrix Inequalities(PLMIs), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. We show that the resulting fuzzy controller guarantees the asymptotic stability and disturbance attenuation of the closed-loop system in spite of controller gain variations within a resulted polytopic region by example and simulations.

• Research in Community and Public Health Nursing
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• v.9 no.1
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• pp.40-63
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• 1998

A long life is the desire of many people. The purpose of this study was to describe long life factors for people aged one hundred and above on Chju island. The research was conducted using a phenomenological method to add understanding to this subject. The field work for this study was done from July, 1997 to February, 1998 on Cheju island. The sample consisted of 10 persons of one hundred or above and 12 families. They were audio-recorded and analyzed using Colaizzi's (1978) method. The results of the present study shows the following: The thoughts of the persons one hundred and above showed ten important concepts; 'dietary regimen', 'mental regimen', 'sleep regimen', 'residence regimen', 'health regimen', 'labor regimen', 'exercise regimen', 'being born', 'filial piety and posterity', 'attachment to life'. Concerning 'Dietary Regimen': Dietary regulation, Preferential food intake, Living on vegetables, Light eating, and concern for longevity in food intake were important. Concerning 'Mental Regimen' : Harmony, Clearheadedness, Mildness, Abstinence, Generosity, Relaxation, Gaiety, Inspiration and Strength were important. Concerning 'Sleep Regimen'; Enough sleeping hours, Sound sleep, Curved sleeping posture, and Comfortable bedding were important. Concerning 'Residence Regimen' ; Clean dwelling, Pleasant surroundings, Thatched house life, Living in the village with good-hearted people, and Regular life were important. Concerning 'Health Regimen'; Temperance of drug, use Proper temperature, Proper humidity, and a Clean body were important. Concerning 'Labor Regimen'; Agricultural labor, Diligence, and Domestic labor were important. Concerning Exercise Regimen': Proper exercise, and Sunbathing were important. Concerning 'Being Born' ; Strong physical constitution, Longevity lineage, and Destiny were important. Concerning 'Filial Piety and Posterity' : Showing respect to a long-lived elder and Reducing anxiety were important. Concerning 'Attachment to Life' ; The desire to live long was important. The following conclusion was made from the above results. Human beings cannot avoid death, but the span of life can be prolonged to the maximum span of human life by wisdom, health care, and proper environmental conditions. As a result, a health regimen must be imposed for longevity such as controling food intake, having positive thoughts, being relaxed, sleeping enough, clean dwelling, taking care of oneself which can improve immunity and resistance to decrease, as well as proper labor and exercise. In addition, when filial piety is served, the desire of longevity and retaining one's youthfulness for a long time can be achieved. These should be done to live long and lead a qualitative life. By the results of this research, the following is suggesed for nursing. To satisfy the basic nursing principle that nursing must be practiced to help people live long, education must be spread to people who are nursed and their family so that they can lead a healthy life. And in nursing elders, nurses must recognize that elders have a strong desire for life, even though they may have negative thoughts about life at times. Therefore nurses have to respect the elders' value of life, and help them improve their self-esteem and self -fulfilment.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.619-625
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• 2008

The effects of thermal cycling on residual stresses in both inorganic passivation/insulating layer that is deposited by plasma enhanced chemical vapor deposition (PECVD) and organic thin film that is used as a bonding adhesive are evaluated by 4 point bending method and wafer curvature method. $SiO_2/SiN_x$ and BCB (Benzocyclobutene) are used as inorganic and organic layers, respectively. A model about the effect of thermal cycling on residual stress and bond strength (Strain energy release rate), $G_c$, at the interface between inorganic thin film and organic adhesive is developed. In thermal cycling experiments conducted between $25^{\circ}C$ and either $350^{\circ}C$ or $400^{\circ}C$, $G_c$ at the interface between BCB and PECVD $ SiN_x $ decreases after the first cycle. This trend in $G_c$ agreed well with the prediction based on our model that the increase in residual tensile stress within the $SiN_x$ layer after thermal cycling leads to the decrease in $G_c$. This result is compared with that obtained for the interface between BCB and PECVD $SiO_2$, where the relaxation in residual compressive stress within the $SiO_2$ induces an increase in $G_c$. These opposite trends in $G_cs$ of the structures including either PECVD $ SiN_x $ or PECVD $SiO_2$ are caused by reactions in the hydrogen-bonded chemical structure of the PECVD layers, followed by desorption of water.

• Safety and Health at Work
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• v.2 no.3
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• pp.282-289
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• 2011

Objectives: We sought to establish a novel method to generate nano-sized carbon black particles (nano-CBPs) with an average size smaller than 100 nm for examining the inhalation exposure risks of experimental rats. We also tested the effect of nano-CBPs on the pulmonary and circulatory systems. Methods: We used chemical vapor deposition (CVD) without the addition of any additives to generate nano-CBPs with a particle size (electrical mobility diameter) of less than 100nm to examine the effects of inhalation exposure. Nano-CBPs were applied to a nose-only inhalation chamber system for studying the inhalation toxicity in rats. The effect on the lungs and circulatory system was determined according to the degree of inflammation as quantified by bronchoalveolar lavage fluid (BALF). The functional alteration of the hemostatic and vasomotor activities was measured by plasma coagulation, platelet activity, contraction and relaxation of blood vessels. Results: Nano-CBPs were generated in the range of 83.3-87.9 nm. Rats were exposed for 4 hour/day, 5 days/week for 4 weeks to $4.2{\times}10^6$, $6.2{\times}10^5$, and $1.3{\times}10^5$ particles/$cm^3$. Exposure of nano-CBPs by inhalation resulted in minimal pulmonary inflammation and did not appear to damage the lung tissue. In addition, there was no significant effect on blood functions, such as plasma coagulation and platelet aggregation, or on vasomotor function. Conclusion: We successfully generated nano-CBPs in the range of 83.3-87.9 nm at a maximum concentration of $4.2{\times}10^6$ particles/$cm^3$ in a nose-only inhalation chamber system. This reliable method can be useful to investigate the biological and toxicological effects of inhalation exposure to nano-CBPs on experimental rats.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.717-722
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• 2011

The purpose of this study is to predict the residual stress in Al6061 during T6 heat treatment. In this study, the variable residual stress in case of the solid solution($530^{\circ}C$, 2h) and artificial ageing($175^{\circ}C$, 9h) of Al6061 subjected to T6 heat treatment is determined at different ageing times. A heat treatment experiment is conducted to determine the heat transfer coefficient, on the basis of which the residual stress during the T6 heat treatment is predicted. In order to take into account the relaxation of residual stress during artificial ageing, a Zener-Wert-Avrami function is used and elasto-plastic nonlinear analysis is conducted through FE-simulation. Further, the residual stress is measured by using the X-ray diffraction(XRD) method, and the result is compared with the result from the FE-simulation. It is found that the residual stress predicted form the FE-simulation is in good agreement with the residual stress measured by using the XRD method.

• Nuclear Engineering and Technology
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• v.4 no.4
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• pp.306-321
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• 1972

Molecular reorientation in (NH$_4$)$_2$SO$_4$, has been studied by cold neutron scattering. For T=300$^{\circ}$K data, the isolated quasielastic spectra and form-factors at various scattering angles are compared with four reorientational models based on SKOLD theory. Front these, it is concluded that the NH$_4$ions are performing either 3-fold four axes or 2-fold three axes reorientation with $\tau$$_{c}$=2.0$\times$10$^{-11}$ sec. The temperature dependence of f. is studied over 100$^{\circ}$K-413$^{\circ}$K and for the high-temperature phase, the widths of composite spectra are compared with the results from NMR relaxation measurements. All the results have shown that the neutron scattering method is capable of giving detalis of the reorientational modes in solids and therefore some discussions are given on the application of this method. A study of the form-factor is applied for NH$_4$I (Phase I) by comparing the measurement with the calculation based on free rotation approximation and proposed a reorientation model of NH$_4$ ions in the octahedral potential cage with $\tau$$_{c}$$\leq$10$^{-12}$ sec. Also a brief theoretical prediction for the effect of reorientational motions on the inelastic spectrum is discussed.sed.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.40-44
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• 2006

[ $Zn_{0.5}Ni_{0.5}Fe_2O_4$ ] nanoparticles have been prepared by a sol-gel method. The structural and magnetic properties have been investigated by XRD, SEM, and Mossbauer spectroscopy, VSM. $Zn_{0.5}Ni_{0.5}Fe_2O_4$ powder that was annealed at $300^{\circ}C$ has spinel structure and behaved superparamagnetically at room temperature. The estimated size of superparammagnetic $Zn_{0.5}Ni_{0.5}Fe_2O_4$ nanoparticle is around 7 nm. The hyperfine fields of the A and I patterns at 4.2 K were found to be 510 and 475 kOe, respectively. The blocking temperature $(T_B)$ of superparammagnetic $Zn_{0.5}Ni_{0.5}Fe_2O_4$ nanoparticle is about 90 K. The magnetic anisotropy constant and relaxation time constant of $Zn_{0.5}Ni_{0.5}Fe_2O_4$ nanoparticle were calculated to be $K=1.6\times10^6erg/cm^3$.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.962-969
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• 1999

Elastic and elasto-plastic stress analyses of AlN/Cu and AlN/W pints produced by active-metal brazing method using Ag-Cu-Ti insert-metal were performed with use of Finite-Element-Method(FEM). The results of stress analyses were compared with those from the pint strength tests and the observations of fracture behaviors. It was shown that a remarkably larger maximum principal stress is built in the AlN/Cu pint compared to the A1N/ W joint. Especially, the stress concentration with tensile component was confirmed at the free surface close to the bonded interface of AlN/Cu. The elasto-plastic analysis under consideration of stress relaxation effect of Ag-Cu-Ti insert possessing a so-called 'soft-metal effect' showed that the insert leads to a lowering of maximum principal stress in AlNiCu pint, even though an increase of the insert thickness above 100$\mu\textrm{m}$ could not bring its further decrease. The maximum pint strengths measured by shear test were 52 and 108 MPa for AlNiCu and AlN/W pints. respectively. Typical fractures of AlN/Cu pints occurred in a form of 'dome' which initiated from the free surface of AlN close to the bonded interface and proceeded towards the AlN inside forming a large angle. AlN/W pints were usually fractured at AlN side along the interface of AlN/insert-metal.