• Corrosion Science and Technology
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• v.11 no.2
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• pp.48-55
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• 2012

Clamping force of a high strength bolt is reduced by a certain period of time after the initial set-up. In case of special treatments on faying surfaces such as protective coating, clamping force is relaxed more severely. Tests for slip critical joints subject to various faying surface parameters were conducted. Five different surface treatments were tested including mill scale surface, blast surface, rust surface and coated surfaces. Each specimen was composed of F10T M20 of high strength bolts and steel plates. Based on the result of slip coefficient test, blast treatment surface showed 0.59, rust treatment surface showed 0.54 and inorganic zinc treatment surface exhibited 0.44. Clean mill treatment surface and red lead paint treatment surface were 0.23, 0.21 respectively. It is identified that the slip coefficient in Korean structural design guide should be determined for various surface conditions. Subsequently from long term relaxation test of ASTM A 490 high strength bolts, relaxation of no-coated surfaces such as blast, clean mill, rust treatment, the loss of initial clamping load was 10.5%, 13.6% and 7.9% for 1,000 hours, while the loss of initial clamping force was reached as 15.0%, 18.7% more than the required redundancy 10% in case of inorganic zinc and red lead painted treatment. It is required that the limit of relaxation on coated faying surface should be established separately for various surfaces.

• Investigative Magnetic Resonance Imaging
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• v.20 no.3
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• pp.181-184
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• 2016

Short inversion time inversion recovery (STIR) is widely used for spinal magnetic resonance imaging (MRI) because the pulse sequence of STIR is insensitive to magnetic field inhomogeneity and can be used to scan a large field of view. In this case report, we present a case of spinal epidural hematoma with unexpected signal decrease on a STIR image. The MRI showed an epidural mass that appeared with high signal intensity on both T1- and T2-weighted images. However, a signal decrease was encountered on the STIR image. This nonspecific decrease of signal in tissue with a short T1 relaxation time that is similar to that of fat (i.e., hemorrhage) could lead to a diagnostic pitfall; one could falsely diagnose this decrease of signal as fat instead of hemorrhage. Awareness of the nonselective signal suppression achieved with STIR pulse sequences may avert an erroneous diagnosis in image interpretation.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.253-259
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• 2015

The information of contrast media concentration on target organ is very important to get reduce the side effect and high contrast imaging. We investigated alternation of signal intensity as a function of the modality of Gd-based contrast media on spin echo and ultra short time echo (UTE) of T1 effective pulse sequence at 3T MRI unit. Gadoxetic acid, which is a MRI T1 contrast medium, was used to manufacture an agarose phantom diluted in various molarities, and sterile water and agarose 2% were used as the buffer solution for the dilution. The gold standard T1 calculation was based on coronal single section imaging of the phantom mid-point with 2D Inversion recovery spine-echo pulse sequence MR imaging for testing of phantom accuracy. The 1-2mmol/L and 7mmol/L was shown the maximum signal intensity on spin echo and UTE respectively. We confirm the difference of contrast media concentration which was shown the maximum signal intensity depending on the T1 effective pulse sequence.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.178-183
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• 1998

Carbon-13 CP-MAS NMR techniques were used to investigate dynamics of new combined type liquid crystalline polymers, poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] and poly[oxy-1,4-phenyleneoxy-2-{10-(4-(4-butylphenylazo)phenoxy)decyloxy}terephthaloyl]. Noticeable mobility change of either aromatic groups or methylene groups is not detected between 25 ℃ and 82 ℃ from 13C spinlattice relaxation time in the rotating frame (T1ρ(C)) and contact time array experiments. However, line shape analysis shows the increase of mobility of methylene carbons in poly[oxy-1,4-phenyleneoxy-2-{6-(4-(4-butylphenylazo)phenoxy)hexyloxy}terephthaloyl] at higher temperature. The dynamics of side chanis does not seem to be affected in our experimental temperature range by the length of aliphatic chain which is connecting the side chain group to the main chain.

• The Journal of Korean Academic Society of Nursing Education
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• v.5 no.1
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• pp.20-38
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• 1999

This study is conducted to test an effect of the guided Imagery program on artificially induced pain and to develop an effective nursing intervention for patients with pain. The subjects of this study were 37 normal female university students. The data were collected from September 1998 to December 1998. And two group non-equal quasi -experimental research with pre and post design was used in this study, The data were analyzed with the SPSS $PC^+$ program with percentage, t-test, paired t-test and ANCOVA. The results of this study were as follows : 1. There are no significant differences of systolic blood pressure between groups. 2. The experimental group showed significantly lower diastolic blood pressure than control group after treatment. 3. There are no significant differences of pulse rate between groups. 4. The experimental group showed significantly higher body temperature than control group after treatment. 5. There are no significant differences of pain intensity between groups. 6. There are no significant differences of pain sensation between groups. 7. There are no significant differences of perceived pain tolerance time between groups. 8. The experimental group showed significantly longer real pain tolerance time than control group after treatment. 9. There are no significant differences of anxiety scores between groups. 10. There are no significant differences of Self-esteem scores between groups. 11. There are no significant differences of Self-esteem scores between groups. 12. There are no significant differences of imagability scores between groups. 13. The post-experimental group showed significantly higher relaxation rate than pre -experimental group. 14. There are no significant differences of imaging depth degree between pre-experimental group and post-experimental group. From the above results, it can be concluded that 1. This guided imagery program could be recommenced as an effective nursing intervention to relieve pain. 2. A follow up study is needed to identify long-term effects.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.28-30
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• 1993

We have investigated the feasibility study, especially for optimal TR, to obtain 3-D MR neurographic imaging (neurograms or nervography) which shows the distribution of peripheral nerve fibers at the human forearm using 4.7 T magnet. To peform a successful formation of MR neurographic imaging, nerve signal should be separated from the other signal comes from surrounding muscle or fat, because nerves are usually embeded in muscle or fat. Generally, it is well known that nerve has shoter T1 value than that of muscle. Thus, repetition time was optimized to maximize the signal intensity defference between the muscel and nerve. We have also used spin-echo(SE) sequence with long echo time($60{\sim}90\;msec$) to enhance the different signal intensity between muscles and pheriperal nerves base on the fact that muscle tissue has longer T2 relaxation lime than that or nerve.

• Investigative Magnetic Resonance Imaging
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• v.21 no.1
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• pp.1-8
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• 2017

Purpose: To investigate the exchange and redistribution of hyperpolarized $^{13}C$ metabolites between different pools by temporally analyzing the relative fraction of dual $T_2{^*}$ components of hyperpolarized $^{13}C$ metabolites. Materials and Methods: A dual exponential decay analysis of $T_2{^*}$ is performed for [1-$^{13}C$] pyruvate and [1-$^{13}C$] lactate using nonspatially resolved dynamic $^{13}C$ MR spectroscopy from mice brains with tumors (n = 3) and without (n = 4) tumors. The values of shorter and longer $T_2{^*}$ components are explored when fitted from averaged spectrum and temporal variations of their fractions. Results: The $T_2{^*}$ values were not significantly different between the tumor and control groups, but the fraction of longer $T_2{^*}$ [1-$^{13}C$] lactate components was more than 10% in the tumor group over that of the controls (P < 0.1). The fraction of shorter $T_2{^*}$ components of [1-$^{13}C$] pyruvate showed an increasing tendency while that of the [1-$^{13}C$] lactate was decreasing over time. The slopes of the changing fraction were steeper for the tumor group than the controls, especially for lactate (P < 0.01). In both pyruvate and lactate, the fraction of the shorter $T_2{^*}$ component was always greater than the longer $T_2{^*}$ component over time. Conclusion: The exchange and redistribution of pyruvate and lactate between different pools was investigated by dual component analysis of the free induction decay signal from hyperpolarized $^{13}C$ experiments. Tumor and control groups showed differences in their fractions rather than the values of longer and shorter $T_2{^*}$ components. Fraction changing dynamics may provide an aspect for extravasation and membrane transport of pyruvate and lactate, and will be useful to determine the appropriate time window for acquisition of hyperpolarized $^{13}C$ images.

• Progress in Medical Physics
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• v.9 no.4
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• pp.207-215
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• 1998

There have been many radiation measurement methods so far among which film dosimetry, TLD, and ion chamber are the most frequently used methods. But this study describes a new radiation measurement method which uses polymer gel and magnetic resonance imaging(MRI). The objective of this study is to fabricate a polymer gel sensitive to radiation and to generate a dose to MRI contrast relationship, and to apply this results to the radiation measurement for the brachytherapy. To do this, 12 cm diameter cylindrical gel phantom was made, and the phantom was irradiated using the 30 mm diameter circular collimator which was used for radiosurgery. And this irradiated phantom was scanned with MRI. To find out the relationship between the radiation dose and the transversal relaxation time, an image processing software(IDL) was used. From this study it is found out that the radiation dose showed linear relationship to the transversal relaxation time of the gel up to 17 Gy($R^2$=0.993) and they had a different relationship above 17 Gy. The dose distributions were calculated using these results for the Ir-192 sources, one for the HDR afterloading system and the other for a 2 mCi seed source. And these calculated dose distributions were compared to the ones from the treatment planning computers. From this study the dose to the irradiated gel's transversal relaxation time relationship was examined, and this result was tried for the measurement of the brachytherapy.

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.1
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• pp.18-25
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• 2018

Replication protein A (RPA) is an essential single-stranded DNA binding protein in DNA processing. It is known that N terminal domain of RPA70 (RPA70N) recruits various protein partners including damage-response proteins such as p53, ATRIP, Rad9, and MRE11. Although the common binding residues of RPA70N were revealed, dynamic properties of the protein are not studied yet. In this study, we measured $^{15}N$ relaxation parameters ($T_1,\;T_2$ and heteronuclear NOE) of human RPA70N and analyzed them using model-free analysis. Our data showed that the two loops near the binding site experience fast time scale motion while the binding site does not. It suggests that the protein binding surface of RPA70N is mostly rigid for minimizing entropy cost of binding and the loops can experience conformational changes.

• Journal of the Korean Society of School Health
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• v.14 no.1
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• pp.145-160
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• 2001

The main purpose of this study is to identify the effects of a structured nursing intervention program on dysmenorrhea in middle school girls. This study employed two methods of research at the same time: a quasi-experiment pre- and post-test to use for comparison. Subjects were middle school girls assigned to the research program: 40 girls in the second grade, 40 girls in the third grade at K Girls' Middle School and H Girls' Middle School located in J city. The data were collected for 68 days from August 23 to October 30, 1999. The data were collected by observation technique and by a self-administered questionnaire. The instruments used for this study were as follows: the "Face Interval Pain Scale" menstrual pain instrument developed by McGreth(1987) and the "Menstrual Distress Questionnaire" dysmenorrhea instrument developed by Moos(1968). The dysmenorrhea knowledge instrument was developed by the researcher and refered to above. The research procedure was as follows: after preliminary examination, the experimental groups were provided educational programs with O.H.P. films developed by the researcher and with the videotape "first meeting" supported by P&G company and produced by EBS. The groups followed the educational programs twice for two weeks. At the beginning of menstruation, these subjects could choose one among the following choices: * Jacobson's progressively muscle relaxation method and massage treatment * Jacobson's progressively muscle relaxation method and hot bag treatment * Jacobson's progressively muscle relaxation method, a pain killer treatment, and massage treatment * Jacobson's progressively muscle relaxation method, a pain killer treatment, and hot bag treatment The dysmenorrhea of the control group were measured during the same period. The analysis of the collected data was done using an SPSS-PC+, descriptive statistic including real numbers, percentage, averages, standard deviations and t-test, $x^2$ test, and ANCOVA. The results of this study were as follows. (1) The knowledge level of the girls provided with the planned nursing intervention program was higher when compared to these who did not follow the educational programs. (2) The original difference in the dysmenorrhea level having been controled, the dysmenorrhea level made, nevertheless, a statistical difference between the experimental group and the control group(F=63.8, p=.00). Observed pain on quantity measurement of dysmenorrhea showed significant difference depending on the treatment(t=4.6, p=.00). In conclusion, those in the planned nursing intervention program had a higher knowledge level and fewer symptoms than the control group. Accordingly, the nursing intervention program for dysmenorrhea developed by the researcher can be effectively applied in nursing practice and can be the foundation for this kind of program.