• Journal of Biosystems Engineering
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• v.32 no.6
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• pp.395-402
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• 2007

This study was carried out as basic researches to develop the leaf vegetable harvester. This study was conducted to investigate physical and rheological properties of bundled leaf vegetables with stem (Chinese leek, Crown daisy and Chamnamul) as test materials held and picked-up by a machine. Stress-strain behavior, stress relaxation, and strain recovery for the bundled materials were analyzed using simple Maxwell model. Physical and rheological properties of the materials were investigated by measuring rupture load, deformation and stress experimentally. Also, strain recovery time when unloading was measured using super high speed camera. Recorded recovery time for stress-strain behavior was0.026 s for Chinese leek with liner strain recovery, 0.046 s for Crown daisy and 0.05 s for Chamnamul with non-linear strain recovery. Furthermore, the strain recovery time for permanent deformation was 0.026 s, 0.046 s, and 0.05 s for Chinese Leek, Crown daisy and Chamnamul, respectively. Finally, strain recovery time and strain recovery ratio for the test materials were 0.17 s, 60.4% in Chinese leek, 0.12 s, 55.3% in Crown daisy, 0.15 s, 58.7% in Chamnamul. Here strain recovery time means that how fast the test materials are recovered from initial deformation and strain recovery ratio means how much the test materials are recovered from initial deformation. The above results show that the test materials can be held enough and moved by the belts.

• Economic and Environmental Geology
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• v.17 no.2
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• pp.141-147
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• 1984

For the discussion of palaeogeomagnetic field direction and the movement and rotation of geotectonic blocks it is prerequisite to eliminate the secondary remanent magnetization component out of the NRM vector of given rock samples. Among various techniques alternating field and thermal demagnetization methods are most easily applicable and most widely used ones. Physical principle underlying these methods is the concept of relaxation time: Either with an action of external magnetic field or with an elevated temperature relaxation time of magnetic minerals can be drastically shortened. It has been furthermore shown experimentally that the secondary remanent magnetization can be more easily demagnetized than the primary remanent magnetization. Through careful stepwise demagnetization it should also be possible to discriminate the kind of various remanent magnetizations. In addition to the introduction to the underlying physical principles and experimental results of the alternating field and thermal demagnetization this paper gives various practical tips in earring out the demagnetization experiments. Each alternating field and thermal demagnetization instrumentation which is easily adaptable to domestic palaeomagnetic laboratories is also introduced. This paper provides a compact and practical introduction to the methods in palaeomagnetism and would be of interest to present workers and to those who want to embark on research in this field.

• Journal of Preventive Medicine and Public Health
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• v.28 no.4 s.51
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• pp.773-782
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• 1995

The purpose of this study is to reveal how the road traffic noise influences on the response of teachers and students, which composed of conversation, studying, relaxation, and physical disturbances. The research method used in this study was self-administrated questionnaire. Samples of the survey were composed of 420 persons(114 teachers and 306 students) who are exposed to traffic noise less than 65 dB(A) from two junior high schools and 410 persons(140 teachers and 270 students) from two noisy junior high schools which the road traffic noise above 65 dB(A). In the response of both of the teachers and students in noisy(above 65 dB) schools complaints of disturbances of conversation, studying, relaxation, and physical disturbances are much higher than that of less noisy schools' teachers and students(p<0.01). On the occasion of time and season, the subjects answered the traffic noise cause high troublesome and stresses in the afternoon(12:00 - 17:00) and summer respectively. It is necessary to provide governmental comprehensive and fundamental measures to improve the noisy school environments.

• Elastomers and Composites
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• v.54 no.3
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• pp.209-219
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• 2019

It is important to analyze crosslink densities of rubber articles because the physical properties are dependent on the crosslink densities. In this paper, analytical techniques for the measurement of crosslink densities of rubber vulcanizates are described. The most widely used method to measure the crosslink density is a swelling method combined with the Flory-Rehner equation. Application of the interaction parameter (${\chi}$) of rubber and swelling solvent is critical because the crosslink density is absolutely dependent on the ${\chi}$ value. Methods for obtaining ${\chi}$ employ not only solubility parameters of the polymer and swelling solvent but also inverse gas chromatography (IGC). The solubilities of rubbers can be obtained using micro differential scanning calorimetry (${\mu}DSC$), intrinsic viscosity measurement, and UV-visible spectroscopy. Nuclear magnetic resonance (NMR) spectroscopy has been also used for the measurement of the crosslink density using the $T_2$ relaxation time, which is determined by spin-spin relaxation in solid-state NMR. For sulfur-cured rubber vulcanizates, crosslink densities according to the crosslink types of mono-, di-, and polysulfides are measured by treating the rubber samples with a chemical probe composed of thiol and amine compounds. Measurement methods of physical crosslinking by filler, crystallization, and ionic bonding have also been introduced.

• Korean Journal of Adult Nursing
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• v.21 no.5
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• pp.458-467
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• 2009

Purpose: This study was object to the effects of a resistance exercise combined with relaxation therapy on blood pressure, frequency of exercise and physical fitness in elderly women. Methods: Seventy three elderly women participated in an exercise program for 12 months. The exercise program consisted of stretching, massage and resistance training using thera-bands twice a week and 50 minutes in every sessions each week. Repeated measures ANOVA were performed using SAS. Results: After the exercise program there was a significant difference in systolic blood pressure, frequency of exercise, body fat, sitting to standing, walking 2 minutes, sitting on a chair and reaching, and standing on one leg with eyes opened. After 6 months, there was a significant decrease in systolic blood pressure and significant increase in frequency of exercise, body fat, sitting to standing and standing on one leg with eyes opened. In 12 months, there was a significant increase in body fat, 2 minutes walking, and sitting in a chair and reaching. Conclusion: Resistance exercise combined with muscle relaxation therapy would have a positive effect on elderly women. We found that it was helpful for the elderly women in terms of physical fitness.

• PNF and Movement
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• v.14 no.3
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• pp.209-217
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• 2016

Purpose: Treatments using a mirror neuron system, such as 3D virtual reality therapy, are used in stroke rehabilitation, but they need to be constructed according to a detailed procedure. The aims of this study were to analyze electroencephalograms (EEG) during relaxation and action while observing first person perspective (1AE) and third person perspective (3AE) videos of the right hand for 20's. Methods: Thirty participants (Male=4, Female=26) were recruited for this study. Participants were selected by a vividness of movement imagery questionnaire (VMIQ). EEG was measured during relaxxation and during action with 1AE and 3AE videos, focusing on the supination and pronation actions of participants' right hands. An absolute mu rhythm, a relatively high alpha power, and a relative beta power were identified. In each group, one-way repeated measures ANOVA was used for statistical analysis. Results: Measurement of absolute mu rhythms was significantly suppressed for both 1AE and 3AE compared with relaxation in C3 and C4 regions. High alpha wave measurements were significantly suppressed for both 1AE and 3AE in all regions, while beta wave measurements were significantly increased only for 3AE in F3 and F4 regions. Conclusion: Based on this study, we suggest that the mirror neuron system is activated during actions accompanied by action observation, especially actions with 3AE video observation, which can be a great therapeutic mathod in stroke rehabilitation.

• Polymer(Korea)
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• v.36 no.4
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• pp.507-512
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• 2012

Thin (~650 nm) and ultrathin (~50 nm) films of neat PMMA and PMMA containing 5 wt% of methacryl-polyhedral oligomeric silsesquioxane were prepared in this work. The effects of film thickness and POSS on glass transition temperature ($T_g$) and isothermal physical aging were investigated by means of differential scanning calorimetry (DSC). $T_g$ depression was observed as film thickness was decreased and Ma-POSS molecules were incorporated. Enthalpy relaxation (${\Delta}H_{Relax}$) due to the isothermal physical aging was reduced by ultra-thin film thickness and the addition of Ma-POSS. KWW (Kohlrausch-Williams-Watts) equation was used to fit ${\Delta}H_{Relax}$ vs. aging time data providing the fitting parameters; maximum enthalpy recovery (${\Delta}H_{\infty}$), relaxation time (${\tau}$) and non-exponentiality parameter (${\beta}$).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.117-122
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• 2007

LB method is one of the most interesting technique to arrange certain molecular groups at precise position relative to others. Also, the LB deposition technique can fabricate extremely thin organic films with a high degree of control over their thickness and molecular architecture. In this way, new thin film materials can be built up at the molecular level, and the relationship between these artificial structures and the properties of materials can be explored. In this paper, evaluation of physical properties was made for dielectric relaxation phenomena by the detection of the surface pressures and displacements current on the monolayer films of phospolipid monomolecular DLPC. Lipid thin films were manufacture by detecting deposition for the accumulation and the current was measured after the electric bias was applied across the manufactured MIM device. It is found that the phospolipid monolayer of dielectric relaxation takes a little time and depend on the molecular area. When electric bias is applied across the manufactured MIM device by the deposition condition of phospolipid mono-layer, it wasn't breakdown when the higher electric field to impress by increase of deposition layers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.3
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• pp.221-228
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• 1998

In this study, the $\beta$-Polyvinylidene fluoride(PVDF) thin films were fabricated by physical vapor deposition method. Also, the properties of dielectric relaxation were studied to understand carrier's behavior of PVDF thin films, to be regarded as the excellent piezo and pyroelectricity. In the process of vapor deposition, the $\beta$-PVDF thin films have been fabricated under the condition of the substrate temperature at 3$0^{\circ}C$, the applied electric field at 142.8kV/cm and the pressure at 2.0${\times}10^{-5}$torr. The dielectric properties of PVDF have been studied in the frequency range 10Hz to 1MHz at temperature from 30 to $100^{\circ}C$. The relative dielectric constant of $\alpha$ and $\beta$-PVDF were 6.8 and 9.8, respectively, under a frequency of 1kHz. Such a phenomenon was caused by the decrease in intermolecular forces originated by the phase-transition from the TGTG' molecular conformation to the TT planar zig-zag conformation. And the relative dielectric constant is increased as a measuring temperature increases, because of the reduction of relaxation time caused by the decrease of intermolecular force.

• Journal of the Korean Society of Fashion and Beauty
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• v.2 no.2 s.2
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• pp.81-92
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• 2004

This paper examined the utilization pattern of aroma-therapy and relating factors after visiting about 100 skin-care shops registered to the Central Estheticism's Association in Daegu.Kyungbuk areas, in 200. This questionnaire survey was put into practice from September 1st to September 30th, 2003 for one month, study subjects were 643 skin-care-shop users. As for the experience of Aroma-use. while 85.4% of respondents experienced Aroma-use or has been using Aromat, 14.6% had no experience of Aroma-use. As for average frequency of Aroma-use, 32.8% used Aroma one time a week,23.7% everyday, 20.4% one time a month, 12.0% 3 times a week, 11.1% 2 times a week. As for the route of getting information on aroma, 49.5% of Aroma users got the information in skin-care-shop, 28.6% from mass-media such as internet, TV, newspaper, magazine. Regarding the type of preference aromas, 65.4% answered Lavender, 35.3% Rosemary, 35.2% Peppermint, 25.5% Rose, 23.7% Tea tree, 21.1% Jasmin, 19.5% Lemon. As for purposes of Aroma-use, 36.8% answered problematic-skin-control & fatness-control, 33.5% stress-relaxation, 14.8% physical-symptom-relaxation, 12.4% muscle-relaxation, 2.6% other purposes.