• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.547-552
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• 2022

In this study, we secured a technology for manufacturing expanded glass of uniform quality by using general tempered glass, that is, window glass, among automotive glass that is scrapped, and verified whether the manufactured expanded glass can be used for lithium battery fire suppression. The process of manufacturing expanded glass using waste glass is generally divided into Crushing → Milling → Granulation → Expansion → Cooling. With several trials a nd errors. It is obtained a yield of 0.5 ø mm to 2 ø mm spherical particles of 80 % or more. By comparing the surface analysis and physical properties, a more suitable sample was selected as a fire extinguishing agent for lithium batteries, and it was confirmed that the result of the adaptability test for lithium battery fire was satisfactory.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.213-226
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• 2022

In the present study, the corrosion behavior of aluminum Al-7075 tempered (T-6 condition) alloy was evaluated by immersion testing and electrochemical testing in 1.75% and 3.5% NaCl environment at acidic, neutral and basic pH. The data obtained by both immersion tests and electrochemical corrosion tests (potentiodynamic polarization and electrochemical impedance spectroscopy tests) present that the corrosion rate of the alloy specimens is minimum for the pH=7 condition of the solution due to the formation of dense and well adherent thin protective oxide layer. Whereas the solutions with acidic and alkaline pH cause shift in the corrosion behavior of aluminum alloy to more active domains aggravated by the constant flux of acidic and alkaline ions (Cl^- and OH^-) in the media which anodically dissolve the Al matrix in comparison to precipitated intermetallic phases (cathodic in nature) formed due to T6 treatment. Consequently, the pitting behavior of the alloy, as observed by cyclic polarization tests, shifts to more active regions when pH of the solutions changes from neutral to alkaline environment due to localized dissolution of the matrix in alkaline environment that ingress by diffusion through the pores in the oxide film. Microscopic analysis also strengthens the results obtained by immersion corrosion testing and electrochemical corrosion testing as the study examines the corrosion behavior of this alloy under a systematic evaluation in marine environment.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.45-68
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• 2023

The purpose of this study is to longitudinally analyze impact factors on library use. One of library use indicators, the number of circulated books was statistically analyzed with latent growth model and growth mixture model. Library data from 2014 to 2019 were collected from the National Library Statistics System, and 846 public libraries were analyzed. As results, the number of circulated books were decreased, but it was tempered. Next, with controlling the factor affecting the dependent variable, the size of collection and the number of participants in reading programs provided by public libraries were statistically significant. Lastly, 5 classes were identified by applying the growth mixture model, and the number of librarians was significantly associated with trajectory class membership.

• Journal of Advanced Technology Convergence
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• v.2 no.2
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• pp.9-14
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• 2023

This study is shown the result of the first year to develop an export 1050MPa-class lightweight ductile iron castings Austempered control arm through the research process to obtain the following results. First, the structure of the optimal design Layout design and development of the component, and then achieve them through the Control Arm rigidity and optimal structure design and robust design of the focus areas of the expected stress Control Arm. Second, to develop a Control Arm reflects the high rigidity and high performance lightweight structures. Control Arm them developed to meet the design and rigidity as required by the consumer through the hollow, and to develop a process for the Core. Third, through optimum alloy composition and heat treatment methods will be derived to derive the amount of iron alloy (Cu, Ni, Mo) and Austempered heat treated and tempered condition. Fourth, through the development of optimum molding technology development component to develop the optimum ADI for the low-stiffness, high-rigidity component development, it attempts to develop a high-strength casting forming technology..

• Journal of the Korean Society for Heat Treatment
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• v.36 no.1
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• pp.7-14
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• 2023

We investigated the effect of multiple tempering on the microstructure and mechanical properties of AISI 4340 steel. The austenitized and quenched AISI 4340 steels were tempered at 550, 600, and 650℃ for 1, 2, and 4 h by single-tempering (ST). The multiple tempering was conducted for 4 h by double-tempering (DT, 2 h + 2 h), and quadruple-tempering (QT, 1 h + 1 h + 1 h + 1 h). As tempering temperature increases, yield strength and ultimate tensile strength decrease and elongation increases due to recovery and recrystallization of martensite and coarsening of carbides. At 550℃, as the number of tempering cycles increases, the yield strength and tensile strength decrease at the expense of fracture elongation. At 600 and 650℃, the yield strength and tensile strength increase with increasing the number of tempering cycles while fracture elongation maintains similar values. The multiple tempering at the same tempering time of 4 h improves the modulus of toughness at all tempering temperatures, which is presumed to be due to the change in carbide precipitation behavior by multiple tempering.

• Korean Journal of Materials Research
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• v.33 no.7
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• pp.302-308
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• 2023

The influence of specimen geometry and notch on the hydrogen embrittlement of an SA372 steel for pressure vessels was investigated in this study. A slow strain-rate tensile (SSRT) test after the electrochemical hydrogen charging method was conducted on four types of tensile specimens with different directions, shapes (plate, round), and notches. The plate-type specimen showed a significant decrease in hydrogen embrittlement resistance owing to its large surface-to-volume ratio, compared to the round-type specimen. It is well established that most of the hydrogen distributes over the specimen surface when it is electrochemically charged. For the round-type specimens, the notched specimen showed increased hydrogen susceptibility compared with the unnotched one. A notch causes stress concentration and thus generates lots of dislocations in the locally deformed regions during the SSRT test. The solute hydrogen weakens the interactions between these dislocations by promoting the shielding effect of stress fields, which is called hydrogen-enhanced localized plasticity mechanisms. These results provide crucial insights into the relationship between specimen geometry and hydrogen embrittlement resistance.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.756-761
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• 2006

The physical and sensory properties of puffed mulberry-rice snack (PMRS) by pellet with mulberry leaf and brown rice flour were evaluated at different temper moisture contents and at varying puffing temperatures. The mulberry pellets were prepared using a food extruder to extrude the dough made from mulberry leaf powder and brown rice flour. The mulberry pellets were tempered to 14, 16, and 18% moisture content and were puffed at 220, 230, and 240$^{\circ}C$ for 4, 5, and 6 sec. The specific volume and breaking strength of PMRS increased with heating temperature and time; however, the breaking strength decreased as the moisture content increased. The Hunter L value decreased as the heating temperature and time increased, showing an especially large decrease with increased heating time. The a and b values increased with increasing heating temperature and time. These results indicated that PMRS, which has a distinctive flavor and color, could be effectively used as a functional food with the use of a puffing machine and that PMRS shows potential for use as new snack product.

• Journal of Nutrition and Health
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• v.10 no.1
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• pp.49-58
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• 1977

Nutrition counselors in Korea often encounter difficulty in their attempt to change village women's attitudes regarding food taboos which are counter to good eating habits. There are a great many food superstitions which are not due to religious influence, but seem to be related to shape and composition of food. Many expectant mothers superstitiously avoid eating certain foods for fear that they may cause mental or physical abnormality in their babies. As was shown in a previous survey (Mo, 1966)of villages in all provinces except Jeju Island, such superstitions were common among pregnant and lactating mothers. Many food taboos and superstitions based on non-scientific and irrational ideas do exist even in modern society, and are a major obstacle to nutritionally adequate food consumption. A study of food taboos among women of Jeju Island was undertaken from November to December of 1976, these results to be compared as well with those of the previous study. There were 73 items found to be prohibited during pregnancy. Of these, 48.7% were of the deaf group, 17.4% fish, 5.5% eggs, 4.7% cereal, and only 2.2% fruit. Of 252% women respondents, 111 (45% ) abstained from eating chicken, duck, and shark because of the belief that they would cause their babies to be born with gooseflesh or shark skin. Many of them avoided rabbit meat for fear that their babies might be born with harelip. It was also feared that a baby would become disfigured if his mother ate duck, goat, dog meat, chicken or duck eggs, or soup made of bones. A common superstition was that highly spiced or salty foods would cause the fetus to be hairless. Squid and octopus were believed to cause babies to have weak bones, or none at all. Most of these food taboos were associated with fears concerning Physical structure and appearance of unborn babies. Other taboos were associated with fear of undesirable behavioral characteristics. For example, some mothers thought that a baby would pinch or bite the mother's breast during the weaning period, if crab meat were eaten during pregnancy. Unevenly sliced rice cake, loach, snake meat and eel were also believed to cause a baby to be ill-tempered. The findings of this study are remarkably similar to those of the previous study conducted by the authour in 1966. Most of the same food taboos, based on non-scientific and irrational reasons, were found on Jeju Island as on the peninsula, and thor were similarly wide-spread. The results of correlational analysis show that the most significant factors related to prevalence of food taboos, are level of education and religious background. Number of food taboos is correlated with level of education. Also, food taboos are least freqent among the Christian woman. Proper nutrition education should he undertaken in order to encourage intake of protein-rich food, particularly during pregnancy when nutritional needs of mother and fetus are great.

• Journal of Conservation Science
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• v.30 no.4
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• pp.373-381
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• 2014

Adding temper into clay prevents to shrink and crack, or twist the clay during the dry process. The purpose of this study is to identify the role of temper and the physical property of earthenware coffin according to the clay state modification in the reduction firing based on earthenware coffins found in Naju which had been made in Three Kingdom Period. Clay from the Oryang-dong site in Naju was used as circle shaped samples. The samples were tempered with various proportions (0%, 20%, 40%) and fired in various temperature ($1000^{\circ}C$, $1100^{\circ}C$, $1200^{\circ}C$). Physical properties were identified by macroscopy, an optical microscope (x50), specific gravity and porosity. Chemical components and existence of specific minerals were identified by analysing XRF and XRD. As a result, the more firing temperature increase, clay volume expansion. To prevent the volume expansion, temper was added.

• Journal of Korean Medical classics
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• v.11 no.1
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• pp.361-394
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• 1998

Jeon Kwang(癲狂), term of oriental medicine, corresponds to psychopathy. This is recorded in the 22th chapter of Young Chu(靈樞). Jeon and Kwang come under Eum(陰) and Yang(陽) respectively. The symptoms of Jeon have silence, cry and giggle alternately, muttering, and so on. And those of Kwang have quick-tempered, absurd remarks, slander, and so on. The contents of this chapter are divided into three volumes. The first is descriptive of paroxysmal causes and various symptoms of Jean and methods of acupuncture and moxibustion. The second stales causes, symptoms, and remedy methods of Kwang. And the third describes about Pung Youk(風逆), Kweol Youk(厥逆), So Ki(少氣), and Tan Ki(短氣). A paragraph concerning of Mok Ja(目眥), so to speak side of pupil, is mentioned at the begginning of this chapter incomprehensibly. Si Ma(馬蒔) asserted that this one is not a pleonasm because mental condition is seen at Mok Ja. But Sa-Deok Jeong(程士德) decided this one doesn't relation to Jeon Kwang. In my opinion, both views have proprieties. It is in a controversy whether Jeon Kwang has somthing to do with Pung Youk, Kweol Youk, etc. Tan Pa(丹波) asserted that these don't have connection each other. But JI-Chong Jang(張志總) explained Jeon Kwang originates in Kweol Youk with a basis of So Mun(素門). It is difficult to judge which opinion is right, but I am of the opinion that paragraphs of Pung Youk and downward mentioned those of other chapter with a mistake in the process of transcription. On accout of not only shortage contents but also ancient writings of this chapter we cannot understand all about Jeon Kwang. In addition, each woodblock-printed book has different letters and every commentaries aren't the same. Till now, therefore, basic study hasn't been done enough to offer a foundation to the theory of medical treatment. The purpose of this study is to correct wrong letters, to take out right commentaries, and then to interpret the accurat meaning of this chapter. I think this bibliographic study is quite meaningful because of hardship to cure psychopathy in clinic as well as of a viewpoint of basic study. However as this thesis is insufficient, so I expect many studies come out later.