In this article, scheduling of a casting sequence is studied in casting foundry which must deliver products according to the Just-in-time(JIT) production policy of a customer. When a foundry manufactures a variety of casts with an identical alloy simultan

① 詩題: <和國信張宗益少卿過潭州朝拜信武殿> 潭州: 文淵閣本과 中華書局本의 《蘇魏公文集》에서의 표기는 모두 “潭州”이지만, 이는 “澶州”의 오기이다. 潭州는 湖南省의 長沙를 가리키는데, 이 潭州는 北宋 元豊3년 이전의 奉使路線과는 동떨어진 남쪽에 위치하고 있다. 澶州에는 眞宗의 神御를 모신 信武殿이 있었고, 蘇頌에 앞서 出使했던 劉敞과 沈遘가 澶州에서 澶淵之役을 회상하며 각각 〈朝謁信武殿二首〉와 〈信武殿〉을 지었다는 점은 필자의 이러한 추정을 뒷받침한다. 張宗益: 蘇頌의 〈前使遼詩〉와 韓琦․文同 등의 시로부터 그가 熙寧 원년을 전후하여 澶州․河間府 (및 相州) 등지에서 봉직했다는 사실을 알 수 있다. 즉 그는 北宋 河北路에서 다년간 근무한 경력이 있으며, 胡宿은 그를 河北東路 방어의 전문가로 인정하고 있다. ② 제1․2구: “夷裔陵邊久, 文明運算高.” 北宋 외교정책의 고명함을 찬양한 것이다. 필자는 기존의 해설을 따른다. ③ 제3․4구: “三冬馳日御, 一夜隕星旄.” 眞宗의 澶州 親臨과 遼나라 장수의 사망 사실을 묘사하고 있다. 이는 각각 沈遘의 〈信武殿〉 및 王安石의 五古와 七古의 〈澶州〉 두 수의 시를 통해서도 확인된다. ④ 제5․6구: “從此通戎賂, 于今襲戰袍.” 澶淵之盟의 결과 遼나라와 교역이 이루어지고 전쟁이 종식되었음을 읊고 있다. 필자는 기존의 해설을 따른다. ⑤ 제7․8구: “威靈瞻廟像, 列侍冩賢豪.” 信武殿에 안치된 眞宗과 신하들의 초상화를 보고 그 모습을 찬양한 것이다. 劉敞이 〈朝謁信武殿二首〉에서 각각 眞宗과 寇準의 초상을 찬양한 점은 필자의 이러한 추정을 뒷받침한다. ⑥ 제9․10구: “民獲耕桑利, 時無斥堠勞.” 평화의 결과 백성들의 살림살이가 나아지고, 요나라에서 침공해 올 염려가 없어졌다는 점을 묘사했다. 필자는 기존의 해설을 따른다. ⑦ 제11․12구: “金繒比干櫓, 未損一牛毛.” 遼나라에 보내는 歲幣는 무기의 비용보다 훨씬 작다는 점을 강조하며 遼나라와의 평화관계를 찬양한 것이다. 필자의 의견은 기존의 해설과 같다. 단 “干櫓”를 中華書局本에서는 “千櫓”라 표기했고, 〈蘇頌使遼詩注釋〉에서는 “櫓”를 “望樓”로 풀이했지만, 그럴 경우 “櫓”는 제10구의 “斥堠”와 의미상 중복된다. 文淵閣本의 표기인 “干櫓”가 올바른 것이라고 생각된다.

Magnesium alloys are alloyed with rare earth elements (Re, Ca, Sr) due to the limited use of magnesium in high-temperature conditions. In this study, the influences of Zr and Zn on the aging behavior of a Mg-Nd-Y alloy were investigated. magnesium alloys containing R.E elements require aging treatments Specifically, Nd, Y and Zr are commonly used for high-temperature magnesium alloys. Various aging treatments were conducted at temperatures of 200, 250 and 300˚C for 0.5, 1, 3, 6, and 10 hours in order to examine the microstructural changes and mechanical properties at a high temperature (150˚C). Hardness and high-temperature (150˚C) tensile tests were carried out under various aging conditions in order to investigate the effects of an aging treatment on the mechanical properties of a Mg-3.05Nd-2.06Y-1.13Zr-0.34Zn alloy. The maximum hardness was 67Hv; this was achieved after aging at 250˚C for 3 hours. The maximum tensile, yield strength and elongation at 150˚C were 237MPa, 145MPa and 13.6%, respectively, at 250˚C for 3 hours. The strengths of the Mg-3.05Nd-2.06Y-1.13Zr-0.34Zn alloy increased as the aging time increased to 3 hours at 250˚C This is attributed to the precipitation of a Nd-rich phase, a Zr-rich phase and Mg3Y2Zn3.

Austenite precipitation behavior was studied with solidification rates and alloying contents, N and Cr, in duplex stainless steels by directional solidification. Directional solidification experiments were carried out with solidification rates, 1~100mm/s, and N and Cr contents, 0~0.27wt.%, 25~28wt.% respectively, in a duplex stainless steel, CD4MCU. As the solidification rate increases, the dendrite spacing reduced and the austenite phase in the ferrite matrix became finer. The volume fraction of austenite phase increased and its shape went to be round with increasing nitrogen contents in duplex stainless alloys. The Cr alloying element, even though it is a ferrite former, showed to enhance the nitrogen solubility in the alloy and caused the austenite round and finer. Also, Cr was supposed to decrease the austenite volume fraction, but it increased the austenite slightly due to increasing nitrogen solubility during solidification.

In this work, the dispersion behavior of particles in binary aluminum (Al)-copper (Cu) cast alloy was investigated with respect to Cu contents of 20 (hypoeutertic), 33 (eutectic) and 40 (hypereutectic) wt.%. In cases of hypo and hypereutectic compositions, SEM images revealed that the primary Al and phases were grown up at the beginning, respectively, and thereafter the eutectic phase was solidified. In addition, it was found that some of particles can be dispersed into the primary Al phase, but none of them are is observed inside the primary 6 phase. This different dispersion behavior of particles is probably due to the difference in the val- ues of specific gravity between particles and primary phases. At eutectic composition, particles were well dispersed in the matrix since there is few primary phases acting as an impediment site for particle dispersion during solidification. Based on the experimental results, it is concluded that particles are mostly dispersed into the eutectic phase in binary Al-Cu alloy system.

The aim of this study was to investigate the cytotoxicity of dental casting gold alloys. Recently, "biocompatability" is considered the most important requirement of dental materials. Dental metals and alloys were estimated by quantity of released ions, which had influenced to living tissues. The requirement of using normal human cells for cytoxicity strudy were abruptly increased. We used the cultured normal human gingival fibroblasts to estimate the cytotoxicity of dental casting gold alloys. The product of S company(Korea, AIGIS-SOFT, AIGIS-PLUS, AIGIS-A, AIGIS-PT, experimental group) and D company's (German, Biocclus inlay, Biolor SG, Stabilor NF Ⅳ, Degulor B, control group) dental casting gold alloys were used. The morphological investigation, hemolysis test, MTT assay and SRB assay were done in vitro. In vivo, inflammatory reaction in rat was examined for 2 weeks. 1. In the result of cytotoxicity assay, there were some differences but was no significancy among the results between two group's hemolysis, MTT and SRB assay. 2. The gingival fibroblasts attached to the surface of dental casting gold alloy showed various features and increased in number as the time had passed. 3. In vivo, chronic inflammatory cell infiltration was prominent from 3 days to 1 week and inflammation was reduced as time had gone. From the aboving results, there were no significant differences in cytoxicity depending on the ratio of gold content, but showed differences depending on the ratio of total precious and non-precious metal content between two groups. In vitro study showed few differences in inflamation reaction.