Thermal management is a critical issue for the development of high-performance electronic devices. In this paper, thermal conductivity values of mild steel and stainless steel(STS) are measured by light flash analysis(LFA) and dynamic thermal interface material(DynTIM) Tester. The shapes of samples for thermal property measurement are disc type with a diameter of 12.6 mm. For samples with different thickness, the thermal diffusivity and thermal conductivity are measured by LFA. For identical samples, the thermal resistance(Rth) and thermal conductivity are measured using a DynTIM Tester. The thermal conductivity of samples with different thicknesses, measured by LFA, show similar values in a range of 5 %. However, the thermal conductivity of samples measured by DynTIM Tester show widely scattered values according to the application of thermal grease. When we use the thermal grease to remove air gaps, the thermal conductivity of samples measured by DynTIM Tester is larger than that measured by LFA. But, when we did not use thermal grease, the thermal conductivity of samples measured by DynTIM Tester is smaller than that measured by LFA. For the DynTIM Tester results, we also find that the slope of the graph of thermal resistance vs. thickness is affected by the usage of thermal grease. From this, we are able to conclude that the wide scattering of thermal conductivity for samples measured with the DynTIM Tester is caused by the change of slope in the graph of thermal resistance-thickness.

송대 신종때는 왕안석 신법 주창으로 정치 불안이 야기되었고, 수많은 문인들은 신법에 반대한다는 이유로 징계를 받아 폄적되는 문학적 암흑기를 거치기도 했다. 하지만, 이런 핍박 속에서도 송나라는 서양의 작품세계와는 차별화된 중국 고유의 문인화, 산수화를 꽃피우기에 이른다. 이 독특한 동양의 작품세계는 시와 그림이 지향하는 작품적 심미주의를 하나의 작품 속에 통합하고, 작품이라는 프레임 속에 문인들의 사상과 철학이 암시적으로 숨겨진다. 이러한 작품세계는 사실을 사실적으로 드러내고 분석하려는 서양의 작품세계와는 차별화된 함축적 비유나 은유적 함의가 시와 그림 속에 그대로 녹여져 있다. 특히, 산수화나 문인화의 은유적 함의는 문자옥(文字狱)과 같은 박해를 피하기 위해 선비들이 언행을 삼가고, 마음을 그림 속에 투영하게 되면서, 작품 속에 숨겨진 은유적 의미들을 서로 공유하는 시대풍조의 산물이 되었다. 그림과 시라는 서로 다른 공간의 예술 활동이 중국 특유의 제화시라는 작품으로 서로 다른 공간들이 하나의 공간에서 그 예술적 가치를 더없이 확대하고 있는 것이다. 중국의 제화시하면 떠오르는 송대 대표적인 산수화 연강첩장도(烟江疊嶂圖) 에 덧붙여진 왕선과 소식의 제화시 연구를 통해 제화시의 가치와 문학사적 의미를 다시 생각해 보는 계기가 되었으면 한다.

《연강임술첩(漣江壬戌帖)》은 겸재 정선이 양천현령시절 제작한 화첩이다. 영조 18년(1742) 10월 보름날, 임술년을 맞아 경기도관찰사 홍경보가 경기 동부지역을 순시 중에 삭녕 우화정으로 경기도 관내 최고의 시인 연천현감 신유한과 최고의 화가 양천현령 정선을 불러들여 연천의 웅연까지 뱃놀이를 즐겼고, 정선은 이 이벤트를 〈우화등선(羽化登船)〉과 〈웅연계람(熊淵繫纜)〉두 점으로 그렸다. 그림의 제목대로 삭녕 우화정에서 배를 타고 출발하는 장면과 웅연에 도착하여 닻을 내리는 장면을 각각 담은 것이다. 이 모임은 같은 임술년(1082)에 가졌던 북송대 문인 소동파(蘇東坡)의 일화에서 비롯되었다. 660년 전의 고사(故事)를 추모하여 재연한 행사였던 셈이다. 이를 밝힌 홍경보의 서문과 신유한의 글 ‘의적벽부(擬赤壁賦)’ 일부, 그리고 정선의 발문(跋文)을 합하여 꾸민 서화첩이 《연강임술첩》이다. 기존에 알려져 있던 화첩본 이외에 새로이 2011년 11월 필자가 참여한 동산방화랑 기획전에 또 다른 《연강임술첩》이 공개되었다. 정선이 화첩의 발문에 밝힌 대로 세 화첩 가운데 두 번째가 출현한 셈이다.《연강임술첩》의 〈우화등선〉(도6)과 〈웅연계람〉(도7) 두 폭은 소동파 적벽부 관련 고사도이자 실경산수화이면서, 동시에 경기도관찰사의 선유 행사를 담은 기록화이다. 옆으로 긴 화면을 적절히 소화한 대가다운 구성방식을 보여준다. 고운 비단에 비교적 강한 먹을 쓰고 옅은 담채와 먹의 농담으로 늦가을의 정취가 살짝 감돌게 그렸다. 강변의 절벽과 암봉(岩峯)은 북종화풍인 농묵의 부벽준(斧劈皴)을, 먼 토산과 근경언덕은 피마준(披麻皴)과 태점(苔點)의 남종산수화풍을 구사했다. 남북종화풍을 조화시켜 임진강변의 풍광을 그렇게 담아낸 것이다. 겸재가 통상 현장사생을 거의 하지 않았듯이, 아마 두 점도 관아에 돌아와 기억으로 이미지를 재구성했을 것으로 본다. 실경그림과 실경현장을 비교하기 난감할 정도로 이상화 시켜 놓았다. ‘의취(意趣)를 살리며 외형 닮기에 소홀히 했다’는 당대 문인 이하곤(李夏坤)의 지적을 실감케 하는 진경작품이다. 그리고 좌우로 긴 풍경에 행사장면과 그 주변 등장인물이나 경물들을 소홀히 다루지 않고, 기록화적 성격까지 적절히 살려놓은 명작이다.

For heat exchanger applications, 2-ply clad materials were fabricated by rolling of aluminum (Al) and mild steel sheets. Effects of annealing temperature on interface properties, especially on inter-layer formation and softening of strain hardened mild-steel, for Al/mild steel clad materials, were investigated. To obtain optimum annealing conditions for the Al/mild steel clad materials, annealing temperature was varied from room temperature to 600˚C. At the annealing temperature about 450˚C, an inter-layer was formed in an island-shape at the interface of the Al/mild steel clad materials; this island expanded along the interface at higher temperature. By analyzing the X-ray diffraction (XRD) peaks and the energy dispersive X-ray spectroscopy (EDX) results, it was determined that the exact chemical stoichiometry for the inter-layer was that of Fe2Al5. In some samples, an X-layer was formed between the Al and the inter-layer of Fe2Al5 at high annealing temperature of around 550˚C. The existence of an X-layer enhanced the growth of the inter-layer, which resulted in the delamination of the Al/mild-steel clad materials. Hardness tests were also performed to examine the influence of the annealing temperature on the cold deformability, which is a very important property for the deep drawing process of clad materials. The hardness value of mild steel gradually decreased with increasing annealing temperature. Especially, the value of hardness sharply decreased in the temperature range between 525˚C and 550˚C. From these results, we can conclude that the optimum annealing temperature is around 550˚C under condition of there being no X-layer creation.

The microstructure of the reagion of carters, created by Cu and W-Cu shaped charge jets, in a 1020 mild steel target has been intestiaged. The region ahead of the crater created by the Cu shaped charge jet, reveals dramatic grain refinement implying the occurrence of a dynamic recrystallization, while that of W-Cu one dose a martensitic transformation indicative of heating up to an austenitic region followed by rapid cooling.The impacting pressure calculated when the W-Cu shaped charge jet encounters the target is higher than that of the Cu one. The micro-hardness of the region ahead of the crater created by the W-Cu shaped charge jet is also higher than that of the Cu one. The microstructure of W-Cu slug remained in the inside of the craters depicts the occurrence of the remarkable elongation of W particles during the liner collaphse. From these results, the microstructural variation of the region ahead of the crater with Cu and W-Cu shaped charge jets is discussed in trems of the pressure dependency of the transformation region of ferrite and austenite phases.

The component materials threatened by cavitation include ship propellers as well as turbine runners, pump impellers, pipe lines and radiators. Today it is known that cavitation damage takes place on many other components including on the coding water side of the cylinder liners of diesel engines. Cavitation erosion - corrosion implies damage to materials due to the shock pressure or shock wave that results when bubbles form and collapse at a metal surface within a liquid. To suppress cavitation erosion as well as cavitation erosion - corrosion to hydraulic equipment, innovations such as the improvement in the geometric design of the equipment or the selection of suitably resistant construction materials are necessary. In this study, we investigated that the cavitation erosion - corrosion damage under vibratory cavitation can be reduced by adding of side now velocity to the cavitation bubble group in order to eliminate bubbles formed in sea water environment.

Cavitation erosion-corrosion implies damage to materials due to the shock pressure or shock wave that results when bubbles form and collapse at a metal surface within a liquid. If the liquids corrosive to the material, a condition typically encountered in industry, the component materials may suffer serious damage by a combination of mechanical and electrochemical attack. To suppress cavitation erosion as well as cavitation erosion-corrosion to hydraulic equipments, innovations such as the improvement in the geometric design of the equipment or the selection of suitably resistant construction materials are necessary. This study was tested by using the piezoelectric vibrator with 20kHz, 24μm for cavitation generation. And also, the vibratory cavitation erosion-corrosion tests on commercial mild steel SS41were carried out. We carefully observed the erosion pattern and surface photography. The geometrical mechanism of pit growth, which is to be likely these processing; shallow typelongrightarrowundercut typelongrightarrowwide shallow type.

각종 환경 조건에서 진동 캐비테이션 침식-부식 시험 장치에 의해 연강(SS41)의 캐비테이션 침식-부식 손상 거동에 관한 연구를 한 결과 다음과 같은 결론을 얻었다. 1) 해수 중에서 캐비테이션 침식-부식 손상 거동은 중앙부와 테두리 부에서 거의 비슷한 정도로 발생하여 성장되지만, 증류수 중에서는 테두리부에서 손상이 먼저 발생한 다음 중앙부에도 손상이 점차 일어난다. 2) 비저항이 낮은 수도수 중의 캐비테이션 침식-부식 손상은 초기에는 비저항이 높은 증류수중에서의 것보다 증가하지만 시간이 경과하면서 CaCO 하(3)의 피막 형성에 의해 둔화된다. 3) 케비테이션 침식-부식 손상 특성은 잠복기, 증가기, 감소기 및 안정기의 4단계로 구분된다.

Background : Corrosion is one of the most devastating problems faced by most industries. Mild steel has played a vital role in various fields due to the excellent mechanical properties of mild steel such as low density, high strength-to-weight ratios, good environmental stability, high thermal conductivity, and corrosion resistance. Methods and Results : The total phenolic contents (TPC) and total flavonoid contents (TFC) of the methanolic extract of C. grandiflora and R. verniciflua leaf have been examined, and its corrosion inhibition performance was investigated by weight loss and electrochemical impedance spectroscopy (EIS) and polarization measurements. The surface morphology of mild steel was analyzed by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) and by atomic force microscopy (AFM). The percentage composition of polyphenolic compounds was found to be higher in C. grandiflora and R. verniciflua plant extracts, and it was proved to be a superior, eco-friendly, and anti-corrosive inhibitor for mild steel in 1M of H2SO4. The Tafel polarization studies indicate that the plant extract is a mixed-type inhibitor. Scanning electron microscopy/energy -dispersive X-ray spectroscopy (SEM-EDS), and atomic force microscopy (AFM) studies confirmed the formation of a protective film on the metal surface. The corrosion inhibition of the C. grandiflora and R. verniciflua plant extracts was characterized by Fourier transform infrared (FT-IR), UV-visible spectra, and wide-angle X-ray diffraction (XRD) studies; these show the strong interaction between the metal surface and the inhibitor. Conclusion : The methanolic extract was prepared the two different plants like C. grandiflora, and R. verniciflua was studied the corrosion inhibition on the mild steel specimen in acidic medium through various methods involving weight loss measurements, EIS, and potentiodynamic polarization. The results shows that the C. grandiflora, and R. verniciflua plant extracts illustrate an effective corrosion inhibitor for mild steel with good anticorrosion properties in acidic environmen