• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.369-378
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• 2000

This study was undertaken to investigate an involvement of nitroxergic innervation in gastric smooth muscle of rat. Isometric tension study, the measurement of single cell length, NADPH diaphorase stain of smooth muscle layers and neuronal nitric oxide synthase (nNOS) western blotting were performed. Sodium nitroprusside (SNP), a nitric oxide donor, relaxed the muscle strips precontracted by acetylcholine (ACh) in a concentration-dependent manner. Pretreatment of L-arginine decreased the contraction induced by electric field stimulation (EFS). Pretreatment of $N^G-nitro-L-arginine$ methyl ester (L-NAME), a NOS inhibitor, increased the EFS-induced contractions. LY 83583, a guanylate cyclase (GC) inhibitor, reversed the inhibitory actions of L-arginine on the muscle contractions. The effects of L-Arginine, L-NAME and LY 83583 on ACh-induced contractions were not significant. L-arginine reduced the EFS-induced contraction in circular muscle, whereas L-NAME enhanced the EFS-induced contraction in longitudinal strips. By EFS, the phasic contractions appeared approximately $20{\sim}25$ seconds later. L-NAME significantly shortened the delay time to about $2{\sim}3$ seconds. In single cell study, ACh contracted gastric smooth muscle cells, SNP relaxed the cells, and the latter also inhibited the ACh-induced contraction. LY 83583 enhanced the ACh-induced contraction and antagonized SNP-induced relaxation. NADPH diaphorase activity was assessed by a histochemistry, nitroblue tetrazolium (NTB) staining. Positive staining was observed in both circular and longitudinal muscle layers. L-arginine increased the staining, while L-NAME decreased the staining. Western blotting for nNOS proved the presence of nNOS in rat gastric smooth muscle. EFS and additional $Ca^{2+}$ increased nNOS protein expression. These results suggest that in rat stomach, both circular and longitudinal muscle layers are innervated with nitroxergic nerves which relax the gastric smooth muscle via NO-cGMP pathway.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.232-241
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• 2016

Among city parks, children's parks are more accessible than other parks in the city, and there are many users. They are used not only for children's playgrounds, but also for relaxation and leisure spaces for local residents. On the other hand, as a result of focusing on the quantitative increase by the engineering division by the Urban park Act, the consideration of the users of various classes is insufficient. The purpose of this study was to analyze the actual use of children parks in single - family housing and communal housing areas, and to identify the problems and future directions of the use of children parks. For this purpose, a case study and a document survey were conducted. First, through scholarship research, the theoretical review and the present situation were summarized based on the data, such as the papers and research reports related to the existing children's park. The status of the location, facilities and management were then identified through interviews and site visits with the children's park management staff. As a result, the children's park was utilized as a leisure space with high accessibility in the living area. As a result, the residence time of most users was within 1 hour to 2 hours. In particular, use by elderly people was higher than the use by children. Therefore, it would be desirable to design the future planning of the children's parks and to plan the arrangement in accordance with the future - oriented multi - purpose neighborhood type children's park.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.500-504
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• 2008

The objective of this paper is to evaluate the feasibility of using an optimization model as a effective way to search conjunctive operation scheme to meet two conditions; one is to minimize the electric cost for pumping and another is to meet the water demand for satisfying customers. The feasibility is confirmed as comparing the best combinations of pumps between multi-regional water supply networks from multiple sources which are obtained through an optimization modeling and EPAnet modeling. KModsim model, a network optimization model, was used to determine conjunctive operation scheme in the pipe system. KModsim, based on Lagrangian Relaxation algorithm, is useful for modeling network system and obtaining simultaneously pump combination and water allocation with given input option such as energy unit cost supplying from a source into a consumer, operating pumping combination. This study develops the procedure of determining optimal conjunctive operation scheme with using KModsim model. As a study region, the water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. The EPAnet hydraulic simulation result(Ryu et al, 2007, KSWW) gave input data for optimization model; energy unit price(won/$m^3$), water service available area etc.. It was assured that the combination of pump operation through optimum conjunctive operation is to be optimum scheme to obtain the best economic water allocation with comparison to the hydraulic simulation result such as electric cost and pump combination cases. The results obtained through the study are as follows. First, It was found that a well-allocated water supply scheme, the best combination of pump operation through optimum joint operation, promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. Second, an application of KModSim, a network model, gave the amount of water allocation from each source to a consumer with consideration of economic supply. Finally, in a service area available to supply through conjunctive operation of existing inter-regional water supply networks within short distance, a conjunctive operation is useful for determining each transmission pipeline's service area and maximizing the effectiveness of optimizations in pumping operation time.

• Journal of the Korean Chemical Society
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• v.23 no.4
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• pp.217-236
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• 1979

The author's theory for plastic deformation was applied to superplastic alloys (Zn-Al eutectoid, Al-Cu, Pb-Sn, Sn-Bi, Mg-Al eutectics). The plastic deformation of the superplastic alloys could be described by two Maxwell models connected in parallel which represent two grain boundary flow units. The flow units are characterized by the two parameters $X_{gj}/{\alpha}_{gj}\;and\;{\beta}_{gj}$ (j=l or 2, g signifies the grain boundary) the values of which were obtained by applying our flow equation [Eq. (5)] to experiment. We confirmed that our flow equation describes the superplasticity very well. The curve of strain rate sensitivity m (=${\partial}\;In\;f/{\partial}\;In\;\dot{s})\;vs.\;-In\dot{s}$, where f and s are stress and strain rate, respectively, showed two peaks corresponding to flow unit gl and g2, the separation of the two peaks is determined by the difference between ${\beta}_{g1}\;and\;{\beta}_{g2}$. The condition of superplasticity is also determined by ${\beta}_{gj}$, which satisfies $\dot{s}_{mj}{\leqslant}1.53}{\beta}_{gj}$ [Eq.(13)], where $\dot{s}_{mj}$ is the s of the jth unit at the peak. The grain size dependence of ${\beta}_{gj}$ is described by $ln({\beta}_{gj})^{-1}$=alnx+b [Eq. (16)], where x is the grain size, and a and b are constants. The activation enthalpy for each flow unit, ${\Delta}H_{gj}^{\neq}$ was also determined from the temperature dependence of ${\beta}_{gj}$ which is proportional to the relaxation time of the j th unit. Since the superplasticity is determined by Eq. (13), and since ${\beta}_{gj}$ and ${\Delta}H_{gj}^{\neq}$ are related, we obtained the conclusion that superplasticity occurs in the system having small ${\Delta}H_{gj}^{\neq}$ values. The Aej values were equal to the activation enthalpies of grain boundary self-diffusion of the component atoms of the alloys, this accords with our proposed flow mechanism. The ${\Delta}H_{gj}^{\neq}$ value increases with grain size as expected from Eq. (16).

• 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 HCI Society of Korea
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• v.13 no.2
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• pp.5-20
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• 2018

The fully autonomous vehicle, which has been actively studied in a worldwide before commercialization, is expected to become a living space by securing time and space compared to existing automobile. For this reason, interior design of fully autonomous vehicle has become very important. To enhance passenger's experience and satisfaction in fully autonomous vehicle, it is necessary to design an optimized space that can support in-vehicle activities. For this purpose, efforts to analyze the passenger's in-vehicle activities should be preceded. However, there were limited studies that define space and in-Vehicle activities of fully autonomous vehicle in Korea. The purpose of this study is to suggest the guideline of the interior design of fully autonomous vehicle by analyzing and classifying the scope of activities that the passenger can perform within the vehicle. As a method of the study, literature studies on future concept cars, human lifetime behavior and consumer needs had been conducted. As a result in-vehicle activities could be applied in a fully autonomous vehicle. Four in-vehicle activities 'work', 'home life and personal care', 'relaxation' and 'conversation and hobby' had been derived through the analysis of in-vehicle activities. Based on the results, the interior design of fully autonomous vehicle guideline has been suggested. The study is significant because the result of the study can act as a basic study which considers the activities in the fully autonomous vehicle environment.

• 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.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.1
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• pp.40-49
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• 1986

Crack, craze and void are common defects which may be found in the bulk of polymeric materials such as either themoplastics or thermosets. The healing phenomena, autohesion, of these defects are known to be a intrinsic material property of various polymeric materials. However, only a few experimental and theoretical investigations on crack, void and craze healing phenomena for various polymeric materials have been reported up to date [1, 2, 3]. This may be partly due to the complications of healing processes and lacking of appropriate theoretical developments. Recently, some investigators have been urged to study the healing phenomena of various polymenic materials since the significance of the use of polymer based alloys or composites has been raised in terms of specific strength and energy saving. In the earlier published reports [1, 2, 3, 4], the crack and void healing velocity, healing toughness and some other healing mechanical and physical properties were measured experimentally and compared with predicted values by utilizing a simple model such as the reptation model under some resonable assumptions. It seems, however, that the general acceptance of the proposed modeling analyses is yet open question. The crack healing processes seem to be complicate and highly dependent on the state of virgin material in terms of mechanical and physical properties. Furthermore, it is also strongly dependent on the histories of crack, craze and void development including fracture suface morphology, the shape of void and the degree of disentanglement of fibril in the craze. The rate of crack healing may be a function of environmental factors such as healing temperature, time and pressure which gives different contact configurations between two separated surfaces. It seems to be reasonable to assume that the crack healing processes may be divided in several distinguished steps like stress relaxation with molecular chain arrangement, surface contact (wetting), inter- diffusion process and com;oete healing (to obtain the original strength). In this context, it is likely that we no longer have to accept the limitation of cumulative damage theories and fatigue life if it is probable to remove the defects such as crack, craze and void and to restore the original strength of polymers or polymer based compowites by suitable choice of healing histories and methods. In this paper, we wish to present a very simple and intuitive theoretical model for the prediction of healed fracture toughness of cracked or defective polymeric components. The central idea of this investigation, thus, may be the modeling of behavior of chain molecules under healing conditions including the effects of chain scission on the healing processes. The validity of this proposed model will be studied by making comparisons between theoretically predicted values and experimentally determined results in near future and will be reported elsewhere.

• Research in Community and Public Health Nursing
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• v.19 no.1
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• pp.27-35
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• 2008

Purpose: The purpose of this study was to examine the effects of aroma-inhalation on depression, sleep, mood, and smell in stroke patients and their caregivers. Method: This study employed one group pretest-posttest repeated design. Data were collected at three time points: baseline(pre-test), 10 days and 20 days after the intervention(Post-test1 and post-test2, respectively). The sample included a total of 23 subjects. Data were analyzed by SPSS 12.0 program using repeated measure ANOVA. Results: Depression was not statistically significant difference among pre-test, post-test1 and post-test2. Sleep was improved after intervention $37.61{\pm}7.41$(pre-test), $41.22{\pm}8.26$ (post-test1), $44.33{\pm}7.67$(post-test2) (F=8.182. p=.001) Mood was significantly improved after intervention: $16.95{\pm}4.89$(pre-test), $14.89{\pm}6.31$(post-test1), $12.11{\pm}5.04$(post-test2). Smell including smell perception, discomfort due to smell and relation between age and smell was significantly improved after intervention: $2.63{\pm}1.20$ (pre-test). $2.00{\pm}1.16$(post-test1), $1.63{\pm}.96$(post-test2) (F=6.176. p=.006) in smell perception, $2.50{\pm}1.10$ (pre-test). $1.81{\pm}.91$(post-test1), $1.19{\pm}.40$(post-test2) (F=12.26. p=.000) in discomfort due to smell and $3.53{\pm}1.18$(pre-test). $2.59{\pm}1.46$(post-test1), $2.53{\pm}1.33$(post-test2) (F=4.148, p=.025) in relation between age and smell. Conclusion: The results suggest that aroma-inhalation may have an effect on sleep, mood and smell and can be effective nursing intervention to increase the relaxation in stroke patients and their caregivers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.187-201
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• 2016

The purpose of this study was to analyze the smart phone usage experience structure for college students. The phenomenology approach was used by conducting 4 times in-depth interviews with the 7 college students age between 20~23. Collected Data was analyzed by Giorgi's phenomenological method. There were 4 general structure descriptions and 28 themes. General structure descriptions were 'Dependence on smart phone', 'Phenomenon of smart phone usage', 'Results of smart phone usage' and 'Relationship between stress and smart phone'. Themes consisted of 'Ambivalence', 'Positive feelings for smart phones', 'Separation anxiety', 'Negative feelings for smart phones'. 'Dependent feelings for smart phones', 'A sense of unity with smart phones', 'Helpful for my life', 'Deeply involved with my life', 'Useful tool in my life', 'Study, communication, relaxation and health care', 'Maintain personal relationship', 'The most important thing in my life', 'Shallow relationship stress', 'Interference with personal relationship', 'Forming a negative relationship', 'Invasion of privacy', 'Forming a Incorrect relationship', 'Unwanted participation', 'No effort to improve relationship', 'Poor concentration', 'Interference with academic study', 'Study assistance', 'Limited help for study in depth', 'Shelter from the stress', 'Amplification of the stress', 'Obsessive focus', 'Feel separation for the reality' and 'Waste of time'. Smart phone usage make college students dependent on smart phones and had negative influence on both personal relationship and academic results. Usage of smart phone also amplified stress. Therefore we need fundamental principles on usage of smart phone and propose to build cultural etiquette that provides reasonable way to use smartphone.