• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.98-103
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• 2013

In this work, we investigated the enhanced performance of IZO-based TFTs with $HfSiO_x$ gate insulators. Four types of $HfSiO_x$ gate insulators using different diposition powers were deposited by co-sputtering $HfO_2$ and Si target. To simplify the processing sequences, all of the layers composing of TFTs were deposited by rf-magnetron sputtering method using patterned shadow-masks without any intentional heating of substrate and subsequent thermal annealing. The four different $HfSiO_x$ structural properties were investigated x-ray diffraction(XRD), atomic force microscopy(AFM) and also analyzed the electrical characteristics. There were some noticeable differences depending on the composition of the $HfO_2$ and Si combination. The TFT based on $HfSiO_x$ gate insulator with $HfO_2$(100W)-Si(100W) showed the best results with a field effect mobility of 2.0[$cm^2/V{\cdot}s$], a threshold voltage of -0.5[V], an on/off ratio of 5.89E+05 and RMS of 0.26[nm]. This show that the composition of the $HfO_2$ and Si is an important factor in an $HfSiO_x$ insulator. In addition, the effective bonding of $HfO_2$ and Si reduced the defects in the insulator bulk and also improved the interface quality between the channel and the gate insulator.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.115-126
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• 2018

Internationally representative steel design standards have forbidden or limited the application of high-strength steels to tubular joints, partly because of concerns about their unique material characteristics such as high yield ratio. Most of design standards stipulate that for steels whose yield strengths exceed 355 or 360 MPa, the strength equations cannot be utilized or strength reduction factor below 1.0 should be multiplied. However, the mechanical background behind these limitations is not clear. Experimental testing of high-strength steel CHS (circular hollow section) X-joints recently conducted by the authors also clearly indicated that the current limitations might be unduly conservative. As a continuing work, extensive, test-validated numerical analyses were made to investigate the behavior of high-strength steel CHS X-joint under axial compression. Three steel grades covering ordinary to very high strength steels were considered in the analysis. Again it was found that the high strength penalty to the joint strength in current standards is too severe and needs to be relaxed. The high-strength steel joints under the effects of chord stress generally showed higher strength than the ordinary steel joints and their strengths were conservatively predicted by current standards. It is also emphasized that current format of the CHS X-joint strength equation does not reflect observed behavior and needs to be recast.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.505-516
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• 2016

With the development of nanotechnology, nanomaterials are used in various fields. Therefore, the interest regarding the safety of nanomaterial use is increasing and much effort is diverted toward establishment of exposure assessment and management methods. Occupational exposure limits (OELs) are effectively used to protect the health of workers in various industrial workplaces. This study aimed to propose an OEL for domestic multi-walled carbon nanotubes (MWCNTs) based on animal inhalation toxicity test. Basic procedure for development of OELs was examined. For OEL estimation, epidemiological study and quantitative risk assessment are generally performed based on toxicity data. In addition, inhalation toxicity data-based no observed adverse effect level (NOAEL) and benchmark dose (BMD) are estimated to obtain the OEL. Three different estimation processes (NEDO in Japan, NIOSH in USA, and Baytubes in Germany) of OELs for carbon nanotubes (CNTs) were intensively reviewed. From the rat inhalation toxicity test for MWCNTs manufactured in Korea, a NOAEL of $0.98mg/m^3$ was derived. Using the simple equation for estimation of OEL suggested by NEDO, the OEL of $142{\mu}g/m^3$ was estimated for the MWCNT manufacturing workplace. Here, we used test rat and Korean human data and adopted 36 as an uncertainty factor. The OEL for MWCNT estimated in this work is higher than those ($2-80{\mu}g/m^3$) suggested by previous investigators. It may be greatly caused by different physicochemical properties of MWCNT and their dispersion method and test rat data. For setting of regulatory OELs in CNT workplaces, further epidemiological studies in addition to animal studies are needed. More advanced technical methods such as CNT dispersion in air and liquid should be also developed.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.727-737
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• 2013

The purpose of this study was to investigate the middle school students' perception and their learning satisfaction in SMART learning based science instruction. Three types of modules on the solar system and lunar phases unit at the middle school level were developed and lessons on each module were taught to 207 student participants. All participants were provided with tabletPC(iPad2) with iOS5 installed, and using astronomy app Solar Walk, mirroring function, QR code, and Google Presentation, the lessons were carried out both in classroom and at home. The instrument for assessing students' perception on the SMART learning-based instruction was developed based on 4 factors including Self-directed, Motivation, Adaptiveness, and Technology Embedded, with a Likert scale from 1-5 on 20 items. The learning satisfaction survey instrument was originally from Keller's work (1987), and its test items were adapted and modified. To reveal the perception and learning satisfaction about SMART learning-based science lessons, the participants were comparatively analyzed by gender and science achievement levels. Results indicated that male students showed positive perception for the SMART learning-based instruction. Group with higher science achievement scores showed more positive perception of the SMART learning-based instruction in terms of Self-directed and Motivation factor. Also, the learning satisfaction of male students was higher than female students and group with higher academic ability more satisfied with the SMART learning-based instruction than the low group. The results provide implications for future development of programs and help set a direction of increasing the use of a SMART learning-based science in school.

• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.56-61
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• 2015

PURPOSE. The purpose of this study was to evaluate the effects of the surface treatment and shape of the dental alloy on the composition of the prosthetic work and its metallic ion release in a corrosive medium after casting. MATERIALS AND METHODS. Orion Argos (Pd-Ag) and Orion Vesta (Pd-Cu) were used to cast two crowns and two disks. One of each was polished while the other was not. Two as-received alloys were also studied making a total of 5 specimens per alloy type. The specimens were submersed for 7 days in a lactic acid/sodium chloride solution (ISO standard 10271) and evaluated for surface structure characterization using SEM/EDAX. The solutions were quantitatively analysed for the presence of metal ions using ICP-MS and the results were statistically analysed with one-way ANOVA and a Tukey post-hoc test. RESULTS. Palladium is released from all specimens studied (range $0.06-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$), with the Pd-Cu alloy releasing the highest amounts. For both types of alloys, ion release of both disk and crown pairs were statistically different from the as-received alloy except for the Pd-Ag polished crown (P>.05). For both alloy type, disk-shaped pairs and unpolished specimens released the highest amounts of Pd ions (range $0.34-7.08{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). Interestingly, in solutions submerged with cast alloys trace amounts of unexpected elements were measured. CONCLUSION. Shape and surface treatment influence ion release from dental alloys; polishing is a determinant factor. The release rate of cast and polished Pd alloys is between $0.06-0.69{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$, which is close to or exceeding the EU Nickel Directive 94/27/EC compensated for the molecular mass of Pd ($0.4{\mu}g{\cdot}cm^{-2}{\cdot}week^{-1}$). The composition of the alloy does not represent the element release, therefore we recommend manufacturers to report element release after ISO standard corrosion tests beside the original composition.

• 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 Family Resource Management and Policy Review
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• v.10 no.1
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• pp.83-105
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• 2006

The purposes of this study were to classify types of consumption values and to examine 5 types of art appreciation of university students in Seoul. Five types of art appreciation included fine art exhibition(including photographs, architects, calligraphy works), classical and opera performance, traditional Korean music performance, drama and musical performance, dance performance. The sample for this study consisted of 422 university students of five universities in Seoul. The data were collected using the structured questionnaires. The statistical methods used for the analysis were descriptive statistics, chi-square, factor analysis, and cluster analysis. The major findings are as follows. 1. The result of factors for consumption values of students emerged four factors. These were called as 'materialism', 'honor centered', 'family centered', 'hedonism' value. 2. The cluster analysis was conducted based on these four factors. The result showed 3 groups of consumption value which were called as 'material' honor value group', 'family value group', 'hedonic value group'. 3. The consumption value of university students did not significantly differ according to their demographic variables. 4. The behavior of art appreciation of university students significantly differed by their demographic characteristics and consumption value. The material' honor valued group showed the least chances to make decisions on art appreciation for one's own, which reflected that this group appreciate art to satisfy their honors rather than to enjoy art itself. They also showed the most chances to consider the renownedness of the art work or artists among three groups. And they showed the least chances to pay for the tickets for art appreciation, all of those meant that they appreciate arts unvoluntarily in situational condition. The family valued group showed the most chances to pay for the tickets when they appreciate arts. And therefore they were most susceptible for the prices. The hedonic valued group showed the most interests in art. They decided to appreciate art for their own, and they considered the contents and the highness in the level of the art the most when they appreciate art. And they show the most intention of participation in drama/musical performances, which reflect their interests in hedonic values. Based on these results of this study concluded that the consumption values of university students affected their behavior of art appreciation. Thus, university students' behavior on art appreciation can be effectively developed by education according to their consumption values.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.491-505
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• 1992

The purpose of this research was to understand the structure of the lived experience of parents of a child terminally ill with cancer The research question was “What is the structure of the experience of parents of a child terminally ill with cancer\ulcorner” The sample consisted of 17 parents of children admitted to the cancer units of two university hospitals in Seoul. The unstructured interviews were carried out from October 10, 1991 through January 10, 1992. They were audio-recorded and analysed using Van Kaam's method. Parents ascribed the cause of the cancer to the mother's emotional imbalance during pregnancy, the mother's stress, failure to observe religious rites, food, the parent's sin, misfortune and pollution. The theme clusters were tension, fear and depression experienced during pregnancy, stress that children suffer from abusive parents, failure to observe religious activites, bad luck, and sins committed during a previous life. When the child suffered a recurrence of cancer, the parents experienced negative emotions, nervousness, sorrow. depression and death. The theme clusters were feelings of despair, helplessness, regret, guilt, insecurity, emptyness and apathy. The long struggle with cancer resulted in the loss of economic security, loss of psychological and physical well being, and social withdrawal. The theme clusters were the economic burden of medical cost, giving up treatment, debt, limited medical insurance coverage and blood transfusion. The loss of psychological well being included stress, lack of support systems, inability to carry out responsibilities, lack of trust of the medical ten family breakdown, inappropriate expression of emotion and not disclosing the diagnosis to the child. Physically the parents suffered fatigue, insomnia, loss of appetite, loss of weight, dizzness, headache, psychosomatic symptoms, and increased consumption of liquor and cigarettes. Social withdrawal was manifested by taking time off from work to look after the child, decrease of outside social activities and feelings of isolation. Influences on family life were spousal conflicts, negative response of siblings, separation of the family members and economic hardship. The theme clusters were blaming a spouse for the cause of the illness and disagreements, maladjustment, lonliness, hostility and depression of siblings. The high price of medical care over the long period was a major factor influencing the life of the family. Positive experiences during the child's long illness were the strengthening of support systems and religious beliefs and financial help from social organizations. The support of one's spouse primarily helped to overcome the stress of the long illness. In addition, support was received from parents of other children with cancer and from nurses and religious leaders. The nurse, by providing empathetic support, should be a person with whom parents can express their feelings and share their experiences.

• Journal of Korean Academy of Nursing
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• v.2 no.1
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• pp.35-47
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• 1971

This is a research on general evaluation of the nursing profession which is a professional job, a suitable calling to women and is developing academically day by day. The author gave some questions to the patients, doctors, people, student nurses-themselves and got the following results; (A) General concept about nursing profession A nurse is a member, of a medical team who works for people′s health promotion(50.8%). The reason that the nursing profession is a good one is that it is a rewarding job to care for sick patients(78.9%). The spirit is the most important factor for the nurse(84.8%) and the nursing profession is a suitable calling to women (76%). The description of nurses as "The angels in white dress" is an appropriate one (44.6%) or only a beautiful expression(47.4%) (B) Nurses as actually seen by doctors and patients. They work only obligatorily (47.8%)-Doctors They try to relieve, the patient′s physical discomforts in all sincerity (65.6%), also they to decrease the patient′s mental apprehension (56.7%). (C) Satisfaction in the nursing profession. Nurses satisfaction in the nursing profession is general(68.8%) and student nurses satisfaction in selecting nursing is fulfilled (50.9%). One reason for dissatisfaction among nurses and student nurses is people's failure to understanding the nursing profession(40.1%), One reason for satisfaction is that it is a rewarding job caring for sick patients(35%). (D) Is the nursing professional job? People think the nursing profession is a professional job like doctors or lawyers (60.2%). (E) Are they academic? People think the nurses are academic(37.8%) but nurses read only interesting items in the "Journal of Korean Nurse"(67.7%). (F) Opinions about nurses′going out of the country. Doctors and nurses agree that after 1-2 years′experience in this country(78.5%) and student nurses want to go out where there is on opportunity(73.1%). Student's purpose of going out is to enrich their stock of information(71.3%), doctors think, it is for training in nursing knowledge and skills (47.8%). (G) Opinions about nurse′s social affairs. They want nurses to be controlled(44.4%) and also think that the nurse's demonstration in the National Conte. was reasonable (36.3%). (H) Would you make your daughter a nurse? They favour their daughter′s becoming a nurse(17.4%) because they think it is a rewarding job to care for sick patients(42.5%).

• Journal of the Korean Geotechnical Society
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• v.27 no.9
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• pp.67-76
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• 2011

Bearing capacity of pile foundations in cold region is dominated by adfreeze bond strength between surrounding soil and pile perimeter. Adfreeze bond strength is considered to be the most important design parameter for foundations in cold region. Many studies in last 50 years have been conducted to analyze characteristics of adfreeze bond strength. However, most studies have been performed under constant temperature and normal stress conditions in order to analyze affecting factors like soil type, pile material, loading speed, etc. In this study, both freezing temperature and normal stress acting on pile surface were considered to be primary factors affecting adfreeze bond strength, while other factors such as soil type, pile material and loading speed were predefined. Direct shear box was used to measure adfreeze bond strength between Joomoonjin sand and aluminium because it is easy to work for various roughness. Test was performed with temperatures of > $0^{\circ}C$, $-1^{\circ}C$, $-2^{\circ}C$, $-5^{\circ}C$, and $-10^{\circ}C$ and vertical confining pressures of 1atm, 2atm, and 3atm. Based on the test results, the effects of temperature and vertical stress on adfreeze bond strength were analyzed. The test results showed that adfreeze bond strength increases with decreased temperature and increased vertical stress. It was also noted that two types of distinct sections exist, owing to the rate of increase of adfreeze bond strength along the change of freezing temperature: 1)rapidly increasing section and 2)gradually decreasing section. In addition, the results showed that a main factor affecting adfreeze bond strength switches from friction angle to adhesion as freezing temperature decreases.