• Journal of Conservation Science
• /
• v.32 no.3
• /
• pp.313-320
• /
• 2016

The aim of this study was to obtain information on the ancient material of cast bronze through an investigation of the microstructure and impurity characteristics of the casting. Three Koryo bronze coins were analyzed using an optical microscope, scanning electron microscope, and electron dispersive X-ray analyses were used to determine the composition of the specimens. The three coins had 4 phases: ${\alpha}phase$, ${\delta}phase$, Pb, and impurities ($Cu_2S$). $Cu_2S$ was found to exist near Pb or in ${\delta}phase$. $Cu_2S$ is the inter mediate product of copper ore refining. Therefore, the copper ore was not completely refined. To find out the characteristic of $Cu_2S$, we melt 1)Koryo bronze coin and 2)$Cu_2S$ and Pb powder at 1273 K. The reaction between $Cu_2S$ and Pb at 1273 K yielded fine Cu and black gas, which was identified to be PbS and is presented below: $Cu_2S+Pb{\rightarrow}PbS{\uparrow}+2Cu$.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.11
• /
• pp.483-490
• /
• 2016

Automobile door latch is a fine design and assembly techniques are required in order to produce them in a small component assembly shape such as a spring, injection products, a small-sized motor. The door latch is fixed to not open the door of the car plays an important role it has a direct impact on the driver's safety. In this study, during trimming of the terminals of the connector main components of the car door latch, reduce rollover and conducted a research to find a suitable effective shear surface. Using the Taguchi method with orthogonal array of Finite Element Analysis and optimal Design of Experiments were set up parameters for the shear surface quality of the car door latch connector terminals. The design parameters used in the analysis is the clearance, the radius, and the blank holding force, the material of the connector terminal is a C2600. Trimming process optimum conditions suggested by the analysis has been verified by experiments, the shear surface shape and dimensions of a final product in good agreement with forming analysis results.Taguchi method from the above results in the optimization for the final rollover and effective shear surface improved for a vehicle door latch to the connector terminal can be seen that the applicable and useful for a variety of metal forming processes other than the trimming process is determined to be applicable.

• Biomedical Science Letters
• /
• v.3 no.2
• /
• pp.177-185
• /
• 1997

This study was performed to investigat the prevalence rates disease in industrial workers (16, 453) in Pusan city from Jan. 1, 1993 to Dec. 31, 1995. The results were as follows: The male to female ratio was 1.9:1.0 and average age was 43$\pm$17 in male, 38$\pm$15 in female of subjects. The percentage value of patients was 14.0% in male, 7.4% in female of total patients 1, 932 (11.0%). The prevalence raters of pulmonary tuberculosis, hepatic disease, and occupational hearing loss were significantly increased in male than females (p<0.001). But anaemia and organic solvent poisonings significantly increased in females than males (p<0.001). The prevalence rates of hepatic disease increased significantly in below 29, 30-39 and 40-49 age groups, that of cardiovascular disease increased significantly in the age group over 50 years (p<0.001). According to industrial types, the prevalence rate of cadiovascular disease increased in electricity and constration and shoes and rubber in disease, there of hepatic disease increased in primary metal, transportation and maintenance and other industrial, those of occupational hearing loss in drink and food and machinery. The prevalence rate of disease increased significantly long working duration in all diseases except lead poisoning.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.13 no.2
• /
• pp.193-204
• /
• 1984

The enzymatic properties of the alkaline AL-protease, which had been prepared from the crude zymolyase of Arthrobzoter luteus, was investigated together with its active amino acid residue. Complete inactivaton of the proteolytic activity of AL-protease by either DFP or PMSF was simultaneously accompanied by the loss of its lytic effect on the lysis of yeast cell wall. In the reaction, AL-protease showed the pattern of inactivation to decrease very slowly, as compared to that of chymotrypsin, and that enzyme and DFP were found to react with a molar ratio of 1 : 1. The preparation of AL-protease exhibited no hydrolytic activity in any substrates of polysaccharases, playing a significant role in the lysis of yeast cell wall. The optimum pH and temperature of AL-protease was pH 10.5 and $65^{\circ}C$, respectively. It also showed stability in the pH range from 5 to 11 and at the temperature below $65^{\circ}C$. Through the identification of the amino acid residue in the active site of the $^{32}P$-diisopropylph-osphorylated(DIP) AL-protease modified specifically with $^{32}P$-labeled DFP, AL-protease was found to be a DFP-sensitive which has a mole of active serine residue involved in its proteolytic activity per mole of the enzyme.

• Korean Business Review
• /
• v.11
• /
• pp.277-293
• /
• 1998

The purpose of this study is to analyse the overall relationship between the advertisement expenses and the two major indicies of business performance, that is, the total amount of sales and the discipline have contrasted the expenses for commercial advertisement with the total amount of sales or with the business performance, respectively, utilizing data on a specific product observed through 3 to 5 years. This study attempts to enlarge the scope of observation and the content of analysis. In order to attain the purpose of this study, the rate of increase in the advertisement expenses is taken as the independent variable and the two major indicies of business performance, the total amount of sales and the resultant interest, as the dependent variables. Business companies or firms which have continually been listed on the board of Korea Stock Exchange for 14 years, from 1982 to 1995, were grouped into four major business categories; 1)Food and beverage industries, 2)Fiber, clothings, and leather industries, 3) Medicine, chemistry, oil, coal, and rubber industries, and 4) Assembled mechanics and metallurgy, machinery, and maintenance industries. Utilizing the KIS-DATA, compiled by Korea Credit Evaluation, Ltd., 30 to 40 samples of business companies or firms were randomly selected from each category. Finally 125 samples were selected and put into regression analyses and follow-up tests by appropriate statistical models, in order to verify if there were any noticeable correlations. The final result obtained through the afore-mentioned research method shows that the amount of advertisement expenses has strong correlations with the amount of sales and the resultant interest. Viewed by business category, in the case of fiber, clothings, and leather industries, the relationship turned out to be significant only with the rate of increase in the total amount of sales, while, in the case of food and beverage industries, the rate of increase in the total amount of sales showed a negatively significant correlations.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.11
• /
• pp.1145-1151
• /
• 2015

High pressure components of a gas turbine engine must operate for a long life under severe conditions in order to maximize the performance and minimize the maintenance cost. Enhanced cooling design, thermal barrier coating techniques, and nickel-base superalloys have been applied for overcoming them and furthermore, material modeling, finite element analysis, statistical techniques, and etc. in design stage have been utilized widely. This article aims to evaluate the effects on the low cycle fatigue life of the high pressure turbine nozzle caused by different turbine inlet temperature profiles and installation conditions and to investigate the most favorable operating condition to the turbine nozzle. To achieve it, the structural analysis, which utilized the results of conjugate heat transfer analysis as loading boundary conditions, was performed and its results were the input for the assessment of low cycle fatigue life at several critical zones.

• Economic and Environmental Geology
• /
• v.52 no.5
• /
• pp.485-497
• /
• 2019

The Jade Investiture Books in Joseon Dynasty shows diverse facies with various petrographic characteristics to green and white based on color. In lithologically, the green rocks are jade composed of calcite and serpentine, and the white ones are marbles consisting mainly in crystalline calcite. As a result of X-ray diffraction of jade rocks, the more green in color, the more increased intensity of serpentine appears. Therefore, the grade of jade is correlated with contents of serpentine. The Jade Investiture Books owned by the National Palace Museum of Korea are subdivided with 104 (41.3%) books made by only jade rocks, 98 (38.9%) books made by only marbles, and 50 (19.8%) books mixed with jade rocks and marbles. Among the mixed ones, 47 (18.6%) books consisted mainly of the marbles. This result shows the superior marble books occupy more than half of the total books. The Jade Investiture Books made in early Joseon Dynasty are composed of high grade jade. However, the grade of jade had decreased as the kings changed in process of time, and the composition of marble had increased in reverse proportion of jade. The quality of letter pigments, metal accessories and fabrics also had decreased with jade. These trends are reflected in the aspect of society such as weakening royal authority, national power and finance with the course of time. The jade of the books has different mineralogical characteristics from some modern jade produced in Chuncheon nephrite and Buyeo precious serpentine in Korea. Meanwhile, there is ancient literature that described quarries from Namyang in Hwaseong of Gyeonggi province. This area has a wide distribution of gneiss, limestone and limesilicate rocks are interbedded between muscovite schist. The limesilicate rocks contain diopside, which produced serpentine through alteration. It has possibility to make the Jade Investiture Books using these small amounts of jade through mining activity.

• Bangmulgwan gwa yeongu (The National Museum of Korea Journal)
• /
• v.1
• /
• pp.198-233
• /
• 2024

On April 28, 2021, the bereaved family of the late Samsung Group chairman Lee Kun-Hee made a gift of 9,797 items (in 21,693 pieces) from his estate to the National Museum of Korea. Among the donated cultural heritage are 535 mirrors (in 555 pieces), which constitute the largest proportion of the metal art in the donation. This article discusses a group of mirrors from the donated collection dating to the Western Han and Samhan periods - a total of twenty-three mirrors (twenty-two from the Western Han Dynasty and one from the Samhan Period) - that are presumed to have been found together. However, there is no known case of such a large number of Western Han mirrors being discovered together, raising doubts about whether this group should be considered to have been buried all together. Furthermore, the presence of a Samhan mirror among the group suggests that this one at least must have been found together with a Western Han mirror. Additionally, considering that early Samhan mirrors have been found in the southeastern part of the Korean Peninsula, particularly in the region occupied by Jinhan Confederacy (in present-day Gyeongsangbuk-do Province), it is likely that these mirrors were also excavated somewhere in Jinhan. Also, -18 is a repurposed imitation of a jade eye cover. No similar examples have been found in Korea, China, or Japan, but there are instances of bronze mirrors being used as substitutes for jade burial ornaments that have been identified in China. The repurposing and use of Western Han mirrors as circular ornaments have been observed only in Jinhan in the southern part of the Korean Peninsula, indicating that this item was likely used in Jinhan as well. Further research and discoveries are anticipated in the future.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.1
• /
• pp.525-532
• /
• 2024

This study explores the impact of physical characteristics (e.g., shape, color, material, size, weight, technical features) of smart wristbands and smartwatches on consumers' perceived functional, aesthetic, and symbolic values using an extended technology acceptance model. An online survey was conducted with adult residents of the United States who had experience using smart wristbands or smartwatches. Participants were asked about various physical characteristics of products they had used in the past year or were currently using, and their evaluations of these characteristics. The results revealed that the shape of the front display shape significantly influenced symbolic value, with circle shape and square shpae showing significantly higher symbolic value than rectangle shape. Wristband materials also had a significant impact on symbolic value, with metal and leather showing higher symbolic value among various materials. Additionally, an increase in product size was associated with higher symbolic value. Moreover, certain technical features such as activity tracker, alarm clock, and distance tracking influenced perceived functional value, while functions like time display, GPS, and email influenced perceived aesthetic value. Pedometer, GPS, and email were found to enhance perceived symbolic value. These findings provide valuable insights into consumer preferences for smart wristbands and smartwatches, serving as valuable information for product improvement and new product development.

• Korean Journal of Agricultural Science
• /
• v.7 no.2
• /
• pp.182-189
• /
• 1980

This experiment was carried out to study on methods of processing the fruit base which is to be used for preparing the fruit yoghurts. Common fruits were compared and peach was chosen among them for this purpose by determing the rate of decrease in hardness during the process of cooking. The maturity, temperature of cooking and methods of peeling were tested to maintain the desirable hardness during the process, and the effects of metallic ion addition on the hardness of the flesh were also studied. The results obtained were as follows. 1. The peaches were keeping the most stable texture during cooking, among common fruits, however the hardness of apples were decreased markedly. Rate of decreases in the flesh hardness were high during the initial stages of cooking then slowered in all fruits tested. 2. Flesh hardness of the peaches were largely affected by the temperature of cooking. And the texture of freeze-stored fruits was severly damaged during thawing, so that could be used only for the limited purposes such as for stirred-type yoghurt. 3. Divalent matallic ions, especially calcium ion, were effective for supporting the flesh hardness of peaches during cooking. 4. The optimal concentration of calcium chloride addition was 0.3%, and this resulted in its final concentration in the product under the legal dosage without any subsquent changes in colour and flavor. 5. The effects of calcium chloride addition were greater in the froms of dices than in those of slices, and in overmature fleshs than in immature ones. 6. Treatment of calcium chloride by soaking the slices or dices of lye-peeled peaches in 0.3% solution was found to be adaptable for the practical process.