• Korean Journal of Heritage: History & Science
• /
• v.53 no.1
• /
• pp.24-33
• /
• 2020

In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.31 no.2
• /
• pp.103-117
• /
• 2013

This research analyzed the spatial components and establishment of the Tap-gol Park according to the plans between 1897 to 1916 when the discussions on the construction of the park began and it was accomplished as an urban park. The results are as follows. The establishment of Tap-gol Park can be divided by three period. Firstly, Tap-gol Park was owned by the royal family from 1987 to 1904. The discussions on construction of Tap-gol Park as a first urban park of Gyeongseong(京城) in 1897, and the private houses were tear down in order to secure land for the park in 1899. Gates and fences surrounding of Tap-gol Park were organized and it was opened in 1902 based on park plane of turtle - shaped. The octagonal pavilion for 'Lee-Wang-Jik musical band(李王職音樂隊)' was relocated in the southwestern part of the park in 1903. Secondly, Tap-gol Park was used actively by the public between 1910 to 1913, because it was opened for individuals. Also The boundary of Park were changed by surrounding facilities and recreational facilities and benefits was complemented for users. Tap-gol park was opened at nighttime in August 1913. Tap-gol Park was used as a place of amusement park. Thirdly, commercial facilities were made as the park facility between 1914 to 1916. The purpose of 'Kkikdajeom(喫茶店)' was similar to the one of modern cafes. It was built as a typical Japanese tea-house with a small pond having an island and a bridge constructed inside. With the increase of usage of Tap-gol Park as a recreational area by the citizens in 1916, the pavilion as a rest area and toilet as amenities were supplemented. Superintendent's office was equipped too. Simple chairs made from the wooden logs were installed around greenhouse, concert hall, the Wongaksa Buddhist temple(圓覺寺址十層石塔), and the flower garden was fenced round. After the relocation of Yongsan music band to Tap-gol Park, the existing concert hall was demolished. The shape of the park which was seen from the pictures of the magazines of 1920s were achieved as early as 1916. The importance of this research includes the basis to revise the errors of the preexistence researches and value of historical material of the design plan reference of the park which was accomplished during the Japanese colonial era. Also this research is to study on the spatial components of the modern landscape architecture and parks.

• Electrical & Electronic Materials
• /
• v.12 no.7
• /
• pp.7-11
• /
• 1999

Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).

• Journal of Korean Society of Forest Science
• /
• v.60 no.1
• /
• pp.30-36
• /
• 1983

Plywood, the representative interior decorative or structural material, is so inflammable that it may cause big fires. Therefore, it is required inevitably to manufacture the "Fire retardant treated plywood", and it will be a study on the redrying of treated plywood that we ought to solve. This study was carried out to investigate the absorption of 20% $(NH_4)_2HPO_4$ solution into the soaked plywoods by hot/cold soaking for 3/3, 6/3, 9/3 and 12/3 hours and to study drying process with drying curves and drying rates by press-drying at the platen temperature of 130, 145, 160 and $175^{\circ}C$. Solution absorption of plywoods in hot/cold soaking method increased steadily with the prolonged soaking time, and water absorption is higher than DAP absorption, and then chemical retention (DAP) exceeded the minimum retention [$1.125kg/(30cm)^3$] even in the shortest soaking treatment. Drying curves of water-soaked plywoods inclined more steeply than those of DAP soaked plywoods. And the drying proceeded rapidly with the increase in platen temperature and terminated in 2.5-4 minutes at the temperature of 160 and $170^{\circ}C$. Drying rate also increased generally with the increase of platen temperature. So it was at $175^{\circ}C$ in DAP-soaking and at $160^{\circ}C$ in water-soaking when the drying rate became above 10%/min.

• Journal of the Korean association of regional geographers
• /
• v.6 no.3
• /
• pp.117-138
• /
• 2000

This study is, from the view point of constructive social studies which is the foundation of the 7th curriculum, to explore whether there is any viable program and to investigate it by which students, using photo resources in social studies, can organize their knowledge in the way of self-directed thinking. The main results are as follows: If it is a principle of knowledge construction process of constructive social studies that individual construction (cognitive construction) develops into communal construction(social construction) and yet communal construction develops itself, interacting with individual construction, it will be meet the objectives of social studies. In social studies, photos are a powerful communication tool. communicating with photos enables to invoke not only the visual aspects but also invisible aspects of social phenomena from photos. It, therefore, can help develop thinking power through inquiry learning, which is one of the emphasis of the 7th curriculum. Having analyzed photo resources appeared on the regional textbooks in elementary social studies, they have been appeared that even though the importance and amount of space photo resources occupy per page is big with regard to total resources, most of the photos failed to lad to self-directed thinking but just assistant material in stead. Besides, there appeared some problems with the title, variety, size, position, tone of color, visibility of the photos, and further with the combination of the photos. Developing of photo resources for constructive social studies is to overcome some problems inherent in current text books and to reflect the theoretical background of the 7th curriculum. To develop the sort of photo that can realize the point just mentioned, it would be highly preferable to provide photo database to facilitate study with homepage through web-based interaction. To take advantage of constructive photo resources, the instruction is strategized in four stages, intuition, conflict, accommodation, and equilibration stage. With the advancement of the era of image culture, curriculum developers are required to develop dynamic, multidimensional digital photos rather than static photos when develop text books.

• The Journal of Korean Society for Radiation Therapy
• /
• v.20 no.2
• /
• pp.91-102
• /
• 2008

Purpose: To enlarge the efficiency of operation and establish a constituency for development of new radiotherapy treatment through database which is established by arranging and indexing radiotherapy related affairs in well organized manner to have easy access by the user. Materials and Methods: In this study, Access program provided by Microsoft (MS Office Access) was used to operate the data base. The data of radiation oncology was distinguished by a business logs and maintenance expenditure in addition to stock management of accessories with respect to affairs and machinery management. Data for education and research was distinguished by education material for department duties, user manual and related thesis depending upon its property. Registration of data was designed to have input form according to its subject and the information of data was designed to be inspected by making a report. Number of machine failure in addition to its respective repairing hours from machine maintenance expenditure in a period of January 2008 to April 2009 was analyzed with the result of initial system usage and one year after the usage. Results: Radiation oncology database system was accomplished by distinguishing work related and research related criteria. The data are arranged and collected according to its subjects and classes, and can be accessed by searching the required data through referring the descriptions from each criteria. 32.3% of total average time was reduced on analyzing repairing hours by acquiring number of machine failure in addition to its type in a period of January 2008 to April 2009 through machine maintenance expenditure. Conclusion: On distinguishing and indexing present and past data upon its subjective criteria through the database system for radiation oncology, the use of information can be easily accessed to enlarge the efficiency of operation, and in further, can be a constituency for improvement of work process by acquiring various information required for new radiotherapy treatment in real time.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.10a
• /
• pp.111-124
• /
• 2003

Processes that cause immobilization of contaminants in soil are of great environmental importance because they may lead to a considerable reduction in the bioavailability of contaminants and they may restrict their leaching into groundwater. Previous investigations demonstrated that pollutants can be bound to soil constituents by either chemical or physical interactions. From an environmental point of view, chemical interactions are preferred, because they frequently lead to the formation of strong covalent bonds that are difficult to disrupt by microbial activity or chemical treatments. Humic substances resulting from lignin decomposition appear to be the major binding ligands involved in the incorporation of contaminants into the soil matrix through stable chemical linkages. Chemical bonds may be formed through oxidative coupling reactions catalyzed either biologically by polyphenol oxidases and peroxidases, or abiotically by certain clays and metal oxides. These naturally occurring processes are believed to result in the detoxification of contaminants. While indigenous enzymes are usually not likely to provide satisfactory decontamination of polluted sites, amending soil with enzymes derived from specific microbial cultures or plant materials may enhance incorporation processes. The catalytic effect of enzymes was evaluated by determining the extent of contaminants binding to humic material, and - whenever possible - by structural analyses of the resulting complexes. Previous research on xenobiotic immobilization was mostly based on the application of $^{14}$ C-labeled contaminants and radiocounting. Several recent studies demonstrated, however, that the evaluation of binding can be better achieved by applying $^{13}$ C-, $^{15}$ N- or $^{19}$ F-labeled xenobiotics in combination with $^{13}$ C-, $^{15}$ N- or $^{19}$ F-NMR spectroscopy. The rationale behind the NMR approach was that any binding-related modification in the initial arrangement of the labeled atoms automatically induced changes in the position of the corresponding signals in the NMR spectra. The delocalization of the signals exhibited a high degree of specificity, indicating whether or not covalent binding had occurred and, if so, what type of covalent bond had been formed. The results obtained confirmed the view that binding of contaminants to soil organic matter has important environmental consequences. In particular, now it is more evident than ever that as a result of binding, (a) the amount of contaminants available to interact with the biota is reduced; (b) the complexed products are less toxic than their parent compounds; and (c) groundwater pollution is reduced because of restricted contaminant mobility.

• Journal of Chest Surgery
• /
• v.35 no.2
• /
• pp.94-101
• /
• 2002

All kinds of tissue valves must be pretreated for the inactivation of immunologic properties and the strengthening of tissue before implantation. However, the tissue valves are gradually denatured with the calcification process and they eventually lose their functions. Recent reports have shown the existence of specific calcium binding non collagenous proteins in the calcified area of implanted biomaterials. This experiment was intended to confirm the effect of pretreatment with RGDS(Arg-Gly-Asp-Ser) tetrapeptide on the calcification of subcutaneously implanted bovine pericardium in rats. RGDS tetrapeptide has the same amino acid sequence of attachment site of specific calcium binding non collagenous proteins. Material and Method: All bovine pericardial pieces were fixed with 0.6% glutaraldehyde. The pretreatments were done using 5 different methods, groupI, with normal saline for 60 minutes, groupII, with 0.5% GRSD(Gly-Arg-Scr-Asp) tetrapeptide solution for 60 minutes, group III : with 0.5% RGDS(Arg-Gly-Asp-Ser) tctrapeptide for 30 minutes, group IV ; with 0.5% RGDS for 60 minutes, and group V : with 0.5% RGDS for 120 minutes. The pretreated bovine pericardial pieces were implanted subcutaneously at the abdominal sites of rats. 30 days after the implantation, the implanted bovine pericardial tissue were examined radiologically, biochemically, and histologically to measure the severity of calcification. Result: On the radiological examination, group I ; 68.42$\pm$3.06, group II , 64.25$\pm$5.58 showed significant difference with group III: 48.00$\pm$3.57, group IV; 43.67$\pm$2.31, and group V ; 2.58$\pm$2.47(p<0.05). There was no difference between group I and II(p=0.105). On the biochemical examination, the amount of calcium in group I was , 33.09$\pm$6.59 mg, in group II ; 28.12$\pm$5.50mg, in group III ; 25.42$\pm$7.67mg, in group Ⅵ ; 20.51$\pm$5.11mg, and in group V : 15.43$\pm$4.25mg.

• Korean Journal of Clinical Laboratory Science
• /
• v.48 no.2
• /
• pp.158-167
• /
• 2016

The requirements for medical laboratories ISO 15189 is examined in organization and a quality management system, stressing the importance of evidence, document control, and control of records and clinical material. Medical services are provided from the areas of resource management, and pre-examination, examination and post-examination processes. The main goal of ISO 15189 accreditation is to improve the quality of laboratory services provided for patients and clinical users not only through compliance with consensually developed and harmonized requirements but also by adopting the philosophy of continual improvement using the Plan-Do-Check-Act cycle. Laboratory quality should be evaluated and improved in all steps of the testing process as the state-of-the art indicates that the pre- and post-analytical phases are more vulnerable to errors than the intra-analytical phase. The Korea Laboratory Accreditation Scheme (KOLAS), a national accreditation body, provides medical laboratory accreditations for appropriate approaches to evaluating the competence of a medical laboratory in providing effective services to its customers and clinical users. Adoption of ISO 15189 in 2010s as a government policy has been delayed, and only 5 laboratories have been accredited to date in Korea. The medical laboratories should seek the adoption of ISO 15189 with a positive attitude for quality improvement and strengthening of international competitiveness.

• Korean Journal of Food Science and Technology
• /
• v.2 no.2
• /
• pp.8-16
• /
• 1970

Exploitation of leaf protein concentrates for human consumption is very important. Leaf protein concentrates can be easily prepared by mechanically mincing leaves material and press it for getting the juice. Crude protein can be separated from the juice by aging, adjusting the pH, or heating to $75-80^{\circ}C$ etc. This report deals with the extractability of total-N from 69 species of fresh leaves by mechanical process, and then compared the recovery of leaf protein concentrates from leaf extracts by treating with TCA, pH adjustment and heating. Results are summarized as follows. 1. In general, the greater the content of total-N of leaves the greater the percentage extraction. Extraction of the juice from leaves is needed at least two times. The simple equations are constituted between the total-N (T; %) and the first and second extractability ($E_1,\;E_2;\;%$) of the total-N of leaves, as follows: $E_1=0.8168T\;E_2=0.1830T$ 2. The optimum pH value for coagulating protein from extracts is considered to be 3.5 to 4.5. However, the products of leaf protein concentrate by the pH adjustment of extracts are generally dull in color with rich elasticity. 3. Recoveries of the leaf protein concentrate from extracts by treating methods were in the following order of TCA treatment> pH 4 treatment> pH 3 treatment> heat treatment. The yield of leaf protein concentrates decreased bout 10% with pH 4 treatment, 11.4% with pH 3 treatment, and 14.8% with heat treatment compared with the TCA treatment. 4. The heat treatment is the most benifitial method for the production of leaf protein concentrates with regard to properties of texture, color and yield of products and easiness of the treatment method.