• Journal of Powder Materials
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• v.13 no.5 s.58
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• pp.327-335
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• 2006

In the development of new hydrogen absorbing materials for a next generation of metal hydride electrodes for rechargeable batteries, metastable Mg-Ni-based compounds find currently special attention. Amor phous-nanocrystalline $Mg_{63}Ni_{30}Y_7$ and $Mg_{50}Ni_{30}Y_{20}$ alloys were produced by mechanical alloying and melt-spinning and characterized by means of XRD, TEM and DSC. On basis of mechanically alloyed Mg-Ni-Y powders, complex hydride electrodes were fabricated and their electrochemical behaviour in 6M KOH (pH=14,8) was investigated. The electrodes made from $Mg_{63}Ni_{30}Y_7$ powders, which were prepared under use of a SPEX shaker mill, with a major fraction of nanocrystalline phase reveal a higher electrochemical activity far hydrogen reduction and a higher maximum discharge capacity (247 mAh/g) than the electrodes from alloy powder with predominantly amorphous microstructure (216 mAh/g) obtained when using a Retsch planetary ball mill at low temperatures. Those discharge capacities are higher that those fur nanocrystalline $Mg_2Ni$ electrodes. However, the cyclic stability of those alloy powder electrodes was low. Therefore, fundamental stability studies were performed on $Mg_{63}Ni_{30}Y_7$ and $Mg_{50}Ni_{30}Y_{20}$ ribbon samples in the as-quenched state and after cathodic hydrogen charging by means of anodic and cathodic polarisation measurements. Gradual oxidation and dissolution of nickel governs the anodic behaviour before a passive state is attained. A stabilizing effect of higher fractions of yttrium in the alloy on the passivation was detected. During the cathodic hydrogen charging process the alloys exhibit a change in the surface state chemistry, i.e. an enrichment of nickel-species, causing preferential oxidation and dissolution during subsequent anodization. The effect of chemical pre-treatments in 1% HF and in $10\;mg/l\;YCl_3/1%\;H_2O_2$ solution on the surface degradation processes was investigated. A HF treatment can improve their anodic passivation behavior by inhibiting a preferential nickel oxidation-dissolution at low polarisation, whereas a $YCl_3/H_2O_2$ treatment has the opposite effect. Both pre-treatment methods lead to an enhancement of cathodically induced surface degradation processes.

• Journal of Korean Academy of Nursing
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• v.5 no.1
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• pp.17-30
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• 1975

The concept and definition of nursing and her role have been changing in accordance with the socio-cultural factors of the initial society. At present, nursing is conceptualized as a health care profession assisting man to restore, maintain and promote health by providing knowledge, wilt strength and resources through various processes of interaction. Man′s behavior, of individual and group activities for health inclusive, is driven by the initial man′s value orientation. The purpose of this study is to investigate the value orientation regarding health of rural health center milieu in order to give data for; 1. the planning for the delivery of community nursing service, 2. the health education plan at all level of nursing care activities, and 3. the planning of curriculum for nursing education. A hundred opinion leaders among the labor population residing in rural areas (P-group), hundred and six professional nurses at rural health centers (N-group) were indirectly interviewed through questionaries. And ninety five of N-group were interviewed likewise of their perceptions of P-group (NP-group) from July 15, to October 15, 1974. The result is as follows: 1. Maintenance of health is revealed to be the most valued component for man′s happiness in all the three groups. (P-group: 7.30 S. D.=1.31), (N-group :7.84 S. D. =49), and (NP-group : 5.93 S. D. =2.28) 2. The average value score of the maintenance of health revealed significant difference by P〈.001 level between each of the three groups. (Between N-group and P-group : T= -4.07 P and NP ; T=-6.93, N and NP: T=-9.35) 3. Basic health maintenance activities necessary for maintenance and promotion of personal health were moderately valued by all the three groups, P-group ; 3.74 (S. D. =.43) , N-group: 3.52 (S. D. =.34), NP-group: 3.07 (S. D. :.55) Among the 8 categories of basic health maintenance activities, "food intake" was highly valued by P-group (mean value score; 4.00 S. D=.51) , "exercise and rest" and "personal cleanliness" was highly valued by both P-group (4.02, 4.08) and N-group (4.08, 4.22). 4. The mean value score of basic health maintenance activities revealed significant difference by P〈.001 level between each of the three groups (between P-group and N-group: T=-4, 07, N-and NP: T=-6.93, P and NP T=-9.35) 5. Among the 30 questionaries, dynamic activities for health maintenance were more valued in comparison to passive activities in an tile three groups. 6. In N-group, correlation between the value of basic health maintenance activities and the personal health status personal revealed moderate significance. Correlation between the value of basic health maintenance activities and the age revealed low significance. 7. In group, correlation between the value of basic health maintenance activities and; perception of personal health status revealed non significance, between the age and sex revealed low sign affiance, and between the educational status revealed moderate significance. Recommendations are as follows ; 1. The efforts towards alteration of value orientation concerning health in general in community nursing practice de focussed be that of family Planning. 2. In order to prepare professional nurses competent in understanding individual and group, social science and behavioral science be strength ended in planning nursing curriculum. 3. Milieu of nursing experience during nursing education be Planned to begin at simple nursing problem and move towards complex, f. e. home care towards health crisis situation in order to achieve dynamic role mastery.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.628-641
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• 2006

Statement of problem: Dental magnetic materials have been applied to removable prosthetic appliances, maxillofacial prostheses, obturator and dental implant but they still have some problems such as low corrosion resistance in oral environments. Purpose: To increase the corrosion resistance of dental magnetic materials, surfaces of Sm-Co and Nd-Fe-B based magnetic materials were plated with TiN and sealed with stainless steels. Materials and methods : Surfaces of Sm-Co and Nd-Fe-B based magnetic materials were plated with TiN and sealed with stainless steels, and then three kinds of electrochemical corrosion test were performed in 0.9% NaCl solution; potentiodynamic, potentiostatic, and electrochemical impedance test. From this study, corrosion behavior, amount of elements released, mean average surface roughness values, the changing of retention force, and magnetic force values were measured comparing with control group of non-coated magnetic materials. Results: The values of surface roughness of TiN coated Sm-Co and TiN coated Nd-Fe-B based magnetic materials were lower than those of non coated Sm-Co and Nd-Fe-B alloy. From results of potentiodynamic test, the passive current density of TiN coated Sm-Co alloy were smaller than those of TiN coated Nd-Fe-B alloy and non coated alloys in 0.9% NaCl solution. From results of potentiostatic and electrochemical impedance test, the surface stability of the TiN coated Sm-Co alloy was more drastically increased than that of the TiN coated Nd-Fe-B alloy and non-coated alloy. The retention and magnetic force after and before corrosion test did not change in the case of TiN coated magnetic alloy sealed with stainless steel. Conclusion: It is considered that the corrosion problem and improvement for surface stability of dental magnetic materials could be solved by ion plating with TiN on the surface of dental magnetic materials and by sealing with stainless steels.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.57-68
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• 2007

The mega frame system is becoming popular for the design and construction of skyscrapers because this system exhibits structural efficiency by allowing high rigidity of the structure while minimizing the amount of structural materials to be used. Since the mega frame system is usually adopted for super high-rise buildings, the comfort of occupants may be main concerns in the practical application of this system. For the enhancement of the serviceability of mega frame structures, a semi-active tuned mass damper (STMD) is developed in this study. To this end, a Magnetorheological (MR) damper is employed replacing passive damper as a semi-active damper to improve the control effect of a conventional TMD. Since a conventional finite element model of mega frame structures has significant numbers of DOFs, numerical simulation for investigation of control performances of a STMD is impossible by using the full-order model. Therefore, a reduced-order system using minimal DOFs, which can accurately represent the dynamic behavior of a mega frame structure, is proposed in this study through the matrix condensation technique To improve the efficiency of the matrix condensation technique, multi-level matrix condensation technique is proposed using the structural characteristics of mega frame structures. The efficiency and accuracy of the reduced-order control proposed in this study and the control performance of a STMD were verified using example structures.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.83-90
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• 2011

Priming refers to the incidental activation of knowledge structures, such as trait concepts and stereotypes, by the current situational context. Many studies have shown that the recent use of a trait construct or stereotype, even in an earlier or unrelated situation, carries over for a time to exert an unintended, passive influence on the interpretation of behavior. Recent researches have shown that attitudes and other affective reaction can be triggered automatically by the mere presence of relevant objects and events. So assuming that behavioral responses to fragrance are also represented mentally, they should also be capable of becoming automatically activated, by the same principles that govern the development of automaticity of other representations. On the basis of this theory, this study examined the effect of fragrance on the quality of cosmetic products.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.3 s.40
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• pp.1-8
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• 2006

Higher density integration and adoption of new materials in advanced electronic package systems result in severe electrochemical reliability issues in microelectronic packaging due to higher electric field under high temperature and humidity conditions. Under these harsh conditions, metal interconnects respond to applied voltages by electrochemical ionization and conductive filament formation, which leads to short-circuit failure of the electronic package. In this work, in-situ water drop test and evaluation of corrosion characteristics for SnPb solder alloys in D.I. water and NaCl solutions were carried out to understand the fundamental electrochemical migration characteristics and to correlate each other. It was revealed that electrochemical migration behavior of SnPb solder alloys was closely related to the corrosion characteristics, and Pb was primarily ionized in both D.I. water and $Cl^{-}$ solutions. The quality of passive film formed at film surface seems to be critical not only for corrosion resistance but also for ECM resistance of solder alloys.

• Journal of Music and Human Behavior
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• v.2 no.1
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• pp.35-46
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• 2005

Older adults in the hospice care experience difficulties in expressing their emotional and psychological issues, which has detrimental effect in their well-being. The purpose of this study is to examine how music can be used to facilitate self-expression both verbally and nonverbally in order to decrease negative influences of self-concealment. Four cases were referred from hospice personnel at the hospital, and received music therapy sessions for four month. The total number of session varied from 9 to 11 depending on the conditions of each case. Both qualitative and quantitative data were collected from pre and post test of Self-Concealment Scale and Personal Descriptive Essays. The results indicated that the use of music, especially programed songs were effective in evoking emotional responses with various life-related issues and themes. The posttest indicated that the level of self-concealment has decreased, and also the Personal Descriptive Essays involved increased statements of emotional content after music therapy implementation. The study indicates that music can be used as an significant communicative and expressive medium when working with older adults in the hospice or palliative care, since they experience many difficulties to be engaged in the active expression. Music provide both passive and active experience through listening and participating, and programed music therapy intervention will increase the quality of life through expressive music activities.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.37-46
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• 2005

To date, many viable smart base isolation systems have been proposed and investigated. In this study, a novel friction pendulum system (FPS) and an MR damper are employed as the isolator and supplemental damping device, respectively, of the smart base isolation system. A fuzzy logic controller (FLC) is used to modulate the MR damper because the FLC has an inherent robustness and ability to handle non linearities and uncertainties. A genetic algorithm (GA) is used for optimization of the FLC. The main purpose of employing a GA is to determine appropriate fuzzy control rules as well to adjust parameters of the membership functions. To this end, a GA with a local improvement mechanism is applied. This method is efficient in improving local portions of chromosomes. Neuro fuzzy models are used to represent dynamic behavior of the MR damper and FPS. Effectiveness of the proposed method for optimal design of the FLC is judged based on computed responses to several historical earthquakes. It has been shown that the proposed method can find optimal fuzzy rules and the GA optimized FLC outperforms not only a passive control strategy but also a human designed FLC and a conventional semi active control algorithm.

• Journal of the Korean GEO-environmental Society
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• v.9 no.4
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• pp.23-36
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• 2008

Soil nailing system can be mentioned to a method of supporting as the shear strength of in-situ soils is increased by passive inclusions. In the general soil nailing system, facing walls are used in two kind of a lattice concrete block or a cast in placed concrete wall. A case of lattice concrete blocks is used in slow slopes greater than 1(V):0.7(H). Also, a case of a cast in placed concrete wall is used in steep slopes less than 1(V):0.5(H). The cast in placed concrete walls are constructed to 30 cm thick together with a shotcrete facing. In this study, the assembling soil nailing method as a new soil nailing system will be proposed. This method is assembly construction using precast concrete panels with 20 cm thick. So, the ability of construction and the quality of facings can be improved more than a conventional soil nailing system. This method can be obtained the effects that a global slope stability increase, as precast concrete panels are immediately put on cutting face after excavating a slope. In this study, confining effects of concrete panels using the assembling soil nailing system were found out by large scaled load tests. In the tests, the load-settlement relationship to an assembling soil nailing system due to the stiff facings as concrete panels appeared to be better than a typical soil nailing system with shotcrete facings.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.28-36
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• 2021

It is known that buried rebars inside concrete structures are protected from corrosion due to passive layer. It is very important to delay the timing of corrosion or evaluate a detection of corrosion initiation for the purpose of cost-beneficiary service life of a structure. In this study, corrosion monitoring was performed on concrete specimens considering 3 levels of cover depth(60 mm, 45 mm, and 30 mm), W/C(water to cement) ratio(40.0%, 50.0%, and 60.0%) and chloride concentration(0.0%, 3.5%, and 7.0%). OCP(Open Circuit Potential) was measured using agar-based socket type sensors. The OCP measurement showed the consistent behavior where the potential was reduced in wet conditions and it was partially recovered in dry conditions. In the case of 30 mm of cover depth for most W/C ratio cases, the lowest OCP value was measured and rapid OCP recovery was evaluated in increasing cover depth from 30 mm to 45 mm, since cover depth was an effective protection against chloride ion ingress. As the chloride concentration increased, the effect on the cover depth tended to be more dominant than the that of W/C ratio. After additional monitoring and physical evaluation of chloride concentration after specimen dismantling, the proposed system can be improved with increasing reliability of the corrosion monitoring.