AISI 1541 저망간합금강의 Tempering 변화에 따른 미세조직의 변화에 관한 연구

안재우,최재웅 대진대학교 첨단소재연구소 1999 첨단소재연구소논문집 Vol.2 No.-

본 연구에서는 TEM을 이용하여 냉각조건과 열처리조건을 변화시켜 금속벨트에 상용되는 롤러의 미세구조를 살펴보았다. 워터 쾐칭을 행한 후 템퍼링을 행하지 않은 시편의 경우 기지에서 카바이드 석출물이 없는 전형적인 마르텐사이트 조직을 볼 수 있었다. 스프레이 쾐칭을 행한 후 자기 템퍼링을 행한 시편의 경우는 래스(lath)형 마르텐사이트 조직을 관찰할 수 있었으며, 낮은 온도에서 템퍼링을 하였을 경우 나타나는 작은 천이 카바이드(ex, ε-카바이드) 석출물을 관찰할 수 있었다. 그러나 시편의 안쪽부분에서도 로드(rod)형 카바이드, 쌍정(twin) 라멜라(lamella) 그리고 쌍정 판상 등의 다양한 미세구조를 볼 수 있었는데 이런 현상은 롤러의 안쪽부분이 충분히 쾐칭되지 않았거나 스프레이 쾐칭 후 충분한 열처리를 받지 못했기 때문으로 사려된다. 스프레이 쾐칭을 행한 후 노에서 200℃, 2시간 템퍼링을 행한 시편의 경우는 롤러의 표면과 안쪽부분 모두 다 자기 템퍼링을 행한 시편의 표면과 같은 미세구조를 관찰 할 수 있었다.

과잉니켈을 함유한 니켁-티타늄 합금의 새로운 응용

안종관,이정훈,이해욱,정환국 대진대학교 첨단소재연구소 1999 첨단소재연구소논문집 Vol.2 No.-

니켈이 과잉 함유된 니켈(56.4wt %) -티타늄합금을 이용하여 상온에서 형상기억특성 및 초탄성 특성 이 향상된 응용품(브레지어 와이어, 안경테 및 액튜에이터)을 개발하고 이 합금의 형상기억특성을 조사 하였다. 본 연구에서 사용된 형상기억 재료는 ø5.5의 선재로 가공된 56.4wt % 니켈이 함유된 니켈-티타늄합금을 이용하였다. 형상기억특성의 조사는 인장시험과 DSC를 이용하여 행하였다. 브레지어 와이어 에 응용시 인장능력이 12% 향상된 재료를 개발하였고, 안경테에 응용시에는 냉간가공 없이 인장응력이 25% 이상 향상된 재료를 개발하였다.

마취제 혼합에 따른 Purple Membrane의 광순환반응에 부피 변화에 관한 연구

김기준,이후설 대진대학교 첨단소재연구소 1999 첨단소재연구소논문집 Vol.2 No.-

The excess volumes of mixing of benzyl alcohol, ethyl, alcohol, halothane, and procainein vesicle and in suspensions of several lipids have been etermined at 25℃ using a excess volume dilatometer. the potency of general aneathetics has long been known to correlate with lipid solubility Halobacteriun Halobium, were studied by absorption changes at280nm and fiuorescence ehanges at 330nm. The excess volumes of mixing in egg lecithin were all found to enegative, whereas they were positive in procaine and halothane. This result was confirmed as Miller's supposition.

고망간강의 기계적 성질에 미치는 Mo의 영향

황승준 대진대학교 첨단소재연구소 1998 첨단소재연구소논문집 Vol.1 No.-

Austenitic Mangames Steel is extremely tough non-magnetic alloy which is characterized by high strength, high ductility and excellent resistance to wear. In the form of castings or rolled shapes, it serves many industrial requirements economically and is particularly useful for servere service that combines abrasion and heavy impact such as hammer, Jaw plate. In this study, the effect of Mo addition to the standard manganese steel to improve the mechanical properties was investigated at several heat treatment condition. The mechanical properties of the standard manganese steel was raised by addition of Mo.

초대마모 Clad판재의 기계적 성질에 관한 연구

양재웅 대진대학교 첨단소재연구소 1998 첨단소재연구소논문집 Vol.1 No.-

The overlay welding was performed by an automatic submerged arc welder equipped with the cooling and jig system to minimize the dilution of cladding metal and as well as to prevent the distortion of base plate. Effects of welding conditions on mechanical properties of clad plate were evaluated by means of tensile test, impact test and fracture toughness test, and also the workability and the abrasive wear resistance were examined. Fractures were observed at the side of ductile base steel after tension test however at the side of brittle clad metal after impact test. In fracture toughness test, it was found that crack was propagated along with martensite of the region confined to a very narrow interface of ferrite and austenite. Results of the evaluation were followed; Tensile strength; ????=38.35㎏/㎟, ????=32.95㎏/㎟ Impact absorbed energy; K??=2.5J/㎠ (Clad1), 1.9J/㎠ (Clad2) Fracture toughness; ????=0.3 ㎏/㎜ (Clad1, Clad2) The bend and wear test of the clad plate showed good workability and high abrasive wear resistance.

지능형 로봇 시스템을 위한 다중 로봇 제어 시스템의 설계

여희주 대진대학교 첨단소재연구소 1998 첨단소재연구소논문집 Vol.1 No.-

An intelligent robot control system is developed in such a way that it is capable of coordinating dual arm, handling multiple robotic devices and integrating external sensors such as vision and force sensors. Especially, a programming language and a control architecture are designed to allow multiple multi-axis devices to be moved synchronously. And also, task-level robot language are developed for object-oriented task-description and programming. For this, several manipulator-level robot languages are executed for the robot to perform sensor-based motions such as the tracking of moving target and on-line path modification by using F/T sensor. And a task-level robot language interpreter is desinged to translate a task level robot program into a set of manipulator level language. The control system is implemented by using 32-bit microprocessor board and a realtime multitasking operating system(VxWorks), and verified by a practical experament, in which the system control two industrial robot to successfully execute a coordinated-motion and concurrent motion.

Enhanced phase formation kinetics of Sr_0.7Bi_2.3Ta_20_9 thin films using cation substitution

Kwak, Woo-Chul,Sung, Yun-Mo 대진대학교 첨단소재연구소 2002 첨단소재연구소논문집 Vol.5 No.-

The Ta^5+ ions in sol-gel derived Sr_0.7 Bi_2.3 Ta_2O_9 (SBT) were partially substituted by Zr^4+ to form Sr_0.7 Bi_2.3 Ta_1.7 Zr_0.3 O_9 (SBTZ) thin films and Aurivillius phase formation characteristics were compared for each thin film, X-ray diffraction (XRD) analyses were performed on the thin films heated in the range of 730 to 760˚C at 10˚C intervals and it was found that phase formation and crystal growth were greatly affected bythe film composition and crystallization temperature. Johnson-Mehl-Avrami (JMA) isothermal kinetic analyses were performed on the XRD results and activation energy and Avrami exponent values were determined for the fluorite-to-Aurivillus phase transformation. A reduction of ~82 kJ/mol in activation energy was observed for the SBZT thin films, which revealing the key reason of enhanced kinetics in SBTZ, XRD and scanning electron microscopySEM) showed the remaining of fluorite phase in SBT and the formation of a secondary phase in SBTZ.

유계인 외란을 고려한 강인한 비선형 적응 제어기

이형찬 대진대학교 첨단소재연구소 2002 첨단소재연구소논문집 Vol.5 No.-

In this paper, the adaptive control problem is studied for a class of nonlinear systems in the presence of bounded disturbances. By utilizing a nice property of the studied systems, a novel Lyapunov-based control structure is developed, which avoids the possible control singularity problem in adaptive nonlinear controller. The transient bounds of output tracking error are shown to be explicit functions of initial conditions and design parameters, and the control performance of the closed loop system is guaranteed by suitably choosing the design parameters. Simulation study is provided to verify the theoretical results.

Bottom-ash를 사용한 고유동충전재의 물리적 특성에 관한 실험적 연구

김성수,김동현,김종필 대진대학교 첨단소재연구소 2000 첨단소재연구소논문집 Vol.3 No.-

This investigation aims at the optimum mixing of flexible flowable-fill made of Bottom-ash as an industrial waste. Flowable-fill refer to self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. The two primary advantages of flowable fill over traditional methods are its ease of placement and the elimination of settlement. Therefore, in difficult compaction areas or areas where settlement is a concern, flowable fill should be considered. This study compares Bottom-ash with fine aggregate in physical character. The mixing design indicates a various mixing-rate.

0.05wt%C-1.8wt%Mn 강에서 비금속 개재물과 미세조직의 변화에 미치는 Ti 함량의 영향

이상윤,오영주 대진대학교 첨단소재연구소 2000 첨단소재연구소논문집 Vol.3 No.-

The formation of non-metallic inclusions and microstructures in various titanium contents in low carbon steels have been studied. The increase in titanium contents leads to no variation in fraction of intra granular ferrite because the fine TiNs do not affect the volume fraction of total inclusions, although high titanium steel have lots of fine TiN.