• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.12-15
• /
• 1993

The correlation between electrical conduction and dielectric relaxation properties of copper ion conducting glasses is discussed. The glasses were prepared in the system $CuI-Cu_2S-Cu_2O-MoO_3$ using rapid quenching technique. These glasses have high ionic conductivities at room temperature in the range of $10^{\circ}$[S/m], and the conductivities increase with increasing CuI content. The activation energies for conduction are 0.26 - 0.57 eV. The dielectric relaxation times are 1 - 10uS, and the activation energy for ion jumping are 0.18 - 0.41eV. It is shown that the tendency of conduction properties depending on composition of the glass is similar those of dilectric relaxation.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.546-549
• /
• 1993

The correlation between electrical conduct ion and dielectric relaxation properties of copper ion conducting glasses is discussed. The glasses were prepared in the system $CuI-Cu_2S-Cu_2O-MoO_3$ using rapid quenching technique. These glasses have high ionic conductivities at room temperature in the range of $10^{circ}$[S/m], and the conductivities increase with increasing CuI content. The activation energies for conduction are 0.26-0.57 eV. The dielectric relaxation times are 1-10uS, and the activation energy for ion jumping are 0.18-0.41eV. It is shown that the tendency of conduction properties depending on composition of the glass is similar those of dilectric relaxation.

• Bulletin of the Korean Chemical Society
• /
• v.8 no.4
• /
• pp.230-232
• /
• 1987

Nitrogen-14 quadrupolar relaxation has been observed in the amino proton nmr spectra of TA in acetone and methanol solutions over the temperature range $-83^{\circ}C\; to\;+35^{\circ}C.$ The proton nmr lineshapes were analyzed to yield a $^{14}N$ spin lattice relaxation time $(T_1)_N$ as a function of temperature. Activation energies and correlation times at $25^{\circ}C$ for the molecular reorientation in the two solution phases have been calculated and the results are discussed.

• Physical Therapy Rehabilitation Science
• /
• v.10 no.1
• /
• pp.82-89
• /
• 2021

Purpose: This study is to investigate the muscle activity based on real-time visual feedback training methods by rehabilitative ultrasound image in elderly and correlation between Heckmatt scale grade, muscle tone and thickness. Design: Cross-sectional study: Pilot study Methods: 6 elderly participated in the study with 2 conditions. Under the condition of rehabilitation ultrasound imaging equipment, all subjects performed voluntary maximal muscle contraction of the quadriceps 3 times using visual feedback based on Rehabilitative Ultrasound Imaging 1.0 (RUSI 1.0). Under the condition of only ultrasound images, all subjects performed voluntary maximal muscle contraction of the quadriceps 3 times using ultrasound image-based visual feedback. The muscle thickness and tone of the quadriceps were measured and the grades were classified by Heckmatt scale and all variables were comparative analyzed. Results: Heckmatt scale grade showed a negative correlation with muscle thickness at relaxation (p<0.05), and a negative correlation with the difference value obtained by subtracting muscle thickness at relaxation from muscle thickness at contraction in ultrasound image condition (p<0.05). The muscle tone during relaxation showed a negative correlation with the muscle thickness during relaxation (p<0.05). Conclusion: In the case of voluntary maximum muscle contraction of the quadriceps muscle in the elderly, it can be seen that the muscle thickness is getting larger when the RUSI 1.0-based visual feedback is provided than with only ultrasound image provided. And the lower Heckmatt scale grade is, the thicker the muscle is, and the lower the muscle tone is.

• Investigative Magnetic Resonance Imaging
• /
• v.18 no.1
• /
• pp.1-6
• /
• 2014

Purpose : $T_2{^*}$ relaxation time which includes susceptibility information represents unique feature of tissue. The objective of this study was to investigate $T_2{^*}$ relaxation times of the normal glandular tissue and fat of breast using a 3T MRI system. Materials and Methods: Seven-echo MR Images were acquired from 52 female subjects (age $49{\pm}12 $years; range, 25 to 75) using a three-dimensional (3D) gradient-echo sequence. Echo times were between 2.28 ms to 25.72 ms in 3.91 ms steps. Voxel-based $T_2{^*}$ relaxation times and $R_2{^*}$ relaxation rate maps were calculated by using the linear curve fitting for each subject. The 3D regions-of-interest (ROI) of the normal glandular tissue and fat were drawn on the longest echo-time image to obtain $T_2{^*}$ and $R_2{^*}$ values. Mean values of those parameters were calculated over all subjects. Results: The 3D ROI sizes were $4818{\pm}4679$ voxels and $1455{\pm}785$ voxels for the normal glandular tissue and fat, respectively. The mean $T_2{^*}$ values were $22.40{\pm}5.61ms$ and $36.36{\pm}8.77ms$ for normal glandular tissue and fat, respectively. The mean $R_2{^*}$ values were $0.0524{\pm}0.0134/ms$ and $0.0297{\pm}0.0069/ms$ for the normal glandular tissue and fat, respectively. Conclusion: $T_2{^*}$ and $R_2{^*}$ values were measured from human breast tissues. $T_2{^*}$ of the normal glandular tissue was shorter than that of fat. Measurement of $T_2{^*}$ relaxation time could be important to understand susceptibility effects in the breast cancer and the normal tissue.

• Journal of Institute of Convergence Technology
• /
• v.7 no.1
• /
• pp.7-10
• /
• 2017

In general, the shoe stretcher is utilized to stretching the leather of shoe upper in the longitudinal direction. In the capstone design class, we tried to make a shoe leather stretcher for the ball of foot. Since a natural cow leather was recovered in length according to relaxation time after stretched, it was difficult to predict the initial amount of set up of stretching. In this paper, tensile and relaxation experiments were conducted in order to predict the amount of initial stretching for appropriate tensile length. Apparatus of leather stretching was designed and strains of leather were measured according to relaxation times of 12, 18, 24 hours after stretching of 24 hours. It was revealed that the ratio of the final relaxed strain and the initial applied strain was about 0.404 with R-square of 0.990 for a shoe cow leather.

• Korean Journal of Pharmacognosy
• /
• v.36 no.1 s.140
• /
• pp.17-20
• /
• 2005

We previously reported that the exogenous administration of cumambrin A, a sesquiterpene lactone from the dried flowers of Chrysanthemum boreale Makino has a pharmacological effect on normalization of blood pressure in the spontaneously hypertensive rats (SHR). In the present study, we further investigated the effect of cumambrin A on the relaxation of phenylephrine-induced precontracted rat aortic artery rings. The potency of cumambrin A was than compared to verapamil, a well known $Ca^{2+}-channel$ blocker. The results demonstrate that the isolated rat aortic arteries are relaxed to basal tension at a concentration of $5{\times}10^{-5}\;M$ cumambrin A treatment. The results also show that the phenylephrine-induced contraction is inhibited by a pretreatment of cumambrin A. Co-treatment of cumambrin A and verapamil showed a strong synergetic effect on the relaxation of rat aortic artery rings. Thus, these data demonstrate that cumambrin A is a potent relaxant of rat aortic smooth muscle and suggest that cumambrin A modulates intracellular or extracellular $Ca^{2+}$ mobilization.

• YAKHAK HOEJI
• /
• v.37 no.2
• /
• pp.163-171
• /
• 1993

In order to study the functions of vascular endothelial nitric oxide(NO) generating system, we examined the effects of monomethylarginine(MMA) and dimethylarginine(DMA)(asym., sym.), arginine analogues, on modulation of vascular tone. Also, the concentrations of endogenous arginie and MMA were measured by HPLC in rat aortic tissues. The results were as follows. 1. The maximum relaxation induced by Ach (1.5$\times$10$^{-6}$M) was 80% of the contractility of rings of rat aorta induced by phenylephrine and L-Arg causes endothelium-dependent relaxation of the aorta precontracted with phenylephrine and these relaxation were concentration-dependent. 2. Endothelium-dependent contractility of rings of rat aorta induced by MMA (100 $\mu{M}$), DMA (asym., 100 $\mu{M}$) and DMA (sym., 100 $\mu{M}$) were 25.5%, 27.5% and 16.5% of that induced by phenylephrine respectively. 3. The relaxation of rat aortic ring induced by L-Arg was inhibited by MMA, DMA(asym.) and DMA(sym.). The degrees of inhibition induced by MMA, DMA(asym.) and DMA(sym.) were 45.7%, 37.1% and 18.3%, respectively. 4. The endogenous arginine and monomethylarginine contents in rat aorta were 83 pmoles/mg wet tissue, and 34.9 pmoles/mg wet tissue. After stimulation with Ach, the concentrations of L-Arg and MMA were significantly decreased. These results suggest that there are the strong relationships between the endogenous L-Arg and methylated arginines and NO-generating system.

• PNF and Movement
• /
• v.13 no.4
• /
• pp.197-202
• /
• 2015

Purpose: This study aimed to examine the effects of a proprioceptive neuromuscular facilitation (PNF) program on neck pain, cervical range of motion, pressure pain, and the cervical flexion-relaxation ratio in a visual display terminal (VDT) worker. Methods: We recruited a 33-year-old VDT worker diagnosed with chronic VDT syndrome. The subject was treated using a PNF program for 20 minutes a day, three times a week for six weeks. All evaluations were performed every two weeks on the first test day. Results: The PNF program resulted in a significant improvement in the subject's neck pain, cervical range of motion, pressure pain, and the cervical flexion-relaxation ratio after six weeks, in comparison to the subject's condition before treatment. Conclusion: The PNF program can be used effectively to improve neck pain, cervical range of motion, pressure pain, and the cervical flexion-relaxation ratio in visual display terminal (VDT) workers.

• Journal of Biomedical Engineering Research
• /
• v.36 no.6
• /
• pp.241-250
• /
• 2015

Noninvasive temperature monitoring is feasible with Magnetic Resonance Imaging (MRI) based on temperature sensitive MR parameters such as $T_1$ and $T_2$ relaxation times, Proton Resonance Frequency shift (PRFs), diffusion, exchange process, magnetization transfer contrast, chemical exchange saturation transfer, etc. While the temperature monitoring is very useful to guide the thermal treatment such as RF hyperthermia or thermal ablation, the optimization of the MR thermometry method is essential because the range of temperature measurement depends on the choice of the measurement methods. Useful temperature range depends on the purpose of treatment methods, for example, $42^{\circ}C$ to $45^{\circ}C$ for RF hyperthermia and over $50^{\circ}C$ for thermal ablation. In this paper, MR thermometry methods using $T_1$ and $T_2$ relaxation times and PRFs-based MR thermometry are tried on a 3.0 T MRI system and their results are reported and compared. In addition, the scanning protocol and temperature calculation algorithms from $T_1$ and $T_2$ relaxation times and PRFs are optimized for the different temperature ranges for the purpose of RF hyperthermia and/or thermal ablation.