Oxide-dispersion-strengthened (ODS) alloy has been developed to increase the mechanical strength of metallic materials; such an improvement can be realized by distributing fine oxide particles within the material matrix. In this study, the ODS layer was formed in the surface region of Zr-based alloy tubes by laser beam treatment. Two kinds of Zr-based alloys with different alloying elements and microstructures were used: KNF-M (recrystallized) and HANA-6 (partial recrystallized). To form the ODS layer, Y2O3-coated tubes were scanned by a laser beam, which induced penetration of Y2O3 particles into the substrates. The thickness of the ODS layer varied from 20 to 55 μm depending on the laser beam conditions. A heat affected zone developed below the ODS layer; its thickness was larger in the KNF-M alloy than in the HANA-6 alloy. The ring tensile strengths of the KNF-M and HANA-6 alloy samples increased more than two times and 20–50%, respectively. This procedure was effective to increase the strength while maintaining the ductility in the case of the HANA-6 alloy samples; however, an abrupt brittle facture was observed in the KNF-M alloy samples. It is considered that the initial microstructure of the materials affects the formation of ODS and the mechanical behavior.
Cr-Al alloys are attracting attention as oxidation resistant coating materials for high temperature metallic materials due to their excellent high temperature stability. However, the mechanical properties and oxidation resistance of Cr-Al alloys can be further enhanced, and such attempts are made in this study. To improve the properties of Cr-Al alloys, Si is added up to 5 wt%. Casting specimens with different amounts of Si content are prepared by a vacuum arc remelting method and isothermally heated under steam conditions at 1,100oC for 1 hour. The as-cast microstructure of low Si alloys is mainly composed of only a Cr phase, while Al8Cr5 and Cr3Si phases are also observed in the 5% Si alloy. In the high Si alloy, only Cr and Cr3Si phases remain after the isothermal heating at 1,100oC. It is found that Si additions slightly decrease the oxidation resistance of the Cr-Al alloy. However, the microhardness of the Cr-Al alloy is observed to increase with an increasing Si content.
In this study, the coating of an Al-Cr layer on the surface of a Zircaloy-4 alloy was carried out through plasma pretreatment coating and a laser surface melting process. Two different conditions for laser treatment, severe or minimal surface melting of the Zr alloy substrate, were applied to form the final coating. When there was significant surface melting of the Zr alloy, the solidification microstructure of the newly formed coating layer was mainly composed of needle-shaped Al3Zr, Al(Cr) and Al7Cr phases. On the other hand, the solidification microstructure of the coating layer was mainly composed of Al(Cr) and Al7Cr phases when there was minimal surface melting of Zr base in the laser process. However, when the coating was maintained at 1100 oC for 2 hours, significant inter-diffusion occurred between the phases in the coating. As a result, the upper part of the coating layer was observed to mainly consist of Al3Zr and Al8Cr5 phases, regardless of the laser treatment conditions.
This research focuses on the cadastre and cartographic tradition regarding the representation of Rome that had lasted until the middle of 18th Century. Since the early period of Roman Republic until the early 18th Century, map was considered as a effective medium to record the status of urban facts and also a manifestation of changing perception of reality. These facts allow to diagnose social and conventional changes that had occurred in the field of representation techniques and methodologies derived from diverse intention and objective in elaboration of each map. Cartography also has affinity to architectural drawing as many categories of individuals are involved, clients, researchers, craftsmen, publisher and collectors. Fundamental task of documenting the contemporary physical reality was given to the map, however, as architects had practiced through the drawings, cartographers also reconstruct in subjective way specific buildings and urban aspects according to various needs and demands. As such, philology and imagination play important role as two constitute extreme poles in the evolution of the cadastre. Through analysis of paradigmatic examples in the genealogy of cartography of Rome, it was possible to understand the changing episteme that testify the mentality and custom in the field of visual representation.
This research focuses on the role of Giovanni Marinioni during the formation of the modern cartography and cadastre during the 18th century. Initial study began with Giambattista Nolli's Roman map noticing not much information was available to acknowledge his activities during his Milan period before the departure to Rome. It became evident that Marinoni was a key person to understand the complex circumstances in which the professional training and formation of Giambattista Nolli took place as later worked as an anonymous intern during the elaboration of Theresian Cadastre of Milan. The other important figures are Leandro Anguissola and Giovanni Filippini. Anguissola's position and precedent work facilitated Marinoni's multidisciplinary activities that he had performed in Vienna and Milano in the field of making urban maps of those two cities. On the other hand, Filippini not only collaborated with Marinoni but also introduced Nolli in the field of cartography. These activities show transitional and dual aspects that characterized the period in which important irreversible changes that occur during the reign of Habsburg empire and in the rest of the Europe toward the formation of modern society and state. Marinoni's theories and praxis greatly influenced Nolli's later commitment under the Savoia and later on the elaboration of the 'Pianta Grande di Roma' in 1748.
Main theme of this paper is the evaluation of the historical significance of Luciano Baldessari's exhibition works mainly during the Fifties. In order to understand the formal and logical basis of those project, his relationship with the historical Avant-gardes and the consequences expressed in his pavilion projects for the Breda Industrial Company are analyzed. The first part focuses on the influence of Italian Futurism, German Expressionism and Italian Rationalism on the formation and experience of Baldessari during the interwar years. The encounter with these movements determine the interest but also the principles along which Baldessari represents his idea of object, space and place. Specially his professional activities during Fascism would determine his attitude toward political power and the necessity of autonomy in artistic sphere. In the second part, different themes that Baldessari affronted in each project of Breda Pavilions is analyzed. Another important issue regard the historiography of the contemporary architecture. Often, many important works that lies in the threshold of the disciplines such as painting and sculpture and media art were excluded in the history of architecture just because they do not deal with the architectural object. Recently, many elements such as theatrical project and temporary objects are considered as part of urban reality and architecture with acknowledgment of their capacity to create event and situations. Along this thought, not just the reconfiguration on the territory of architecture in present but also the criterion to evaluate the past history of architecture is changing drastically. This study on the pavilions of Baldessari intends to contribute indirectly on the current issue of dominion of architecture, but also to evaluate objectively recent architecture. Consequently, architectural protagonists such as Baldessari and their ephemeral projects would be evaluated compressively in their multiplicity of significance.
본 연구에서는 합성보존제로 흔히 쓰이는 메칠파라벤과 방부효능을 가지는 천연추출성분인 p-아니식애씨드를 HPLC를 통해 분리분석 하는 방법을 개발하였다. 메칠파라벤과 p-아니식애씨드는 같은 분자량(152.15 g/mol)과 비슷한 구조, 같은 최대흡수파장(250 nm)을 보이기 때문에 HPLC로 분석 시 동일한 RT값(13.3 min)을 갖는다. 본 연구 저자들은 아세틸화 반응을 통해 메칠파라벤을 선택적으로 유도체화 한 후 C18 컬럼을 통해 분석했을 때 두 물질이 분리됨을 확인하였다. 아세틸화반응을 거치면서 메칠파라벤의 피크유지시간이 13.3 min에서 23.9 min으로 이동하였으며, 평균값은 23.9±0.1min, 피크면적 값은 5042882±4778로 일정하게 나타났다. 또한 직선성의 평가에서 결정계수값은 0.9999658로 1에 가까운 값을 보였다. 시료의 검출한계는 1.47μg/mL이었고 정량한계는 4.44μg/mL이었다. 결론적으로 본 연구를 통해 개발된 분석법은 화장품 분야에서 유사한 구조를 가진 보존제 분석에 유용하게 사용될 수 있을 것으로 기대된다.