In this study, we carried out interrupted cutting of carbon steel for machine structure(SM20C) with uncoated carbide tool and analyzed anova test and confidence interval to find influential factor to surface roughness, and obtained regression equation. Rhe results are follows: First, we found that affected factor to surface roughness in interrupted cutting was feed rate. Secondly, the cutting speed and depth of cut was small affected to surface roughness. Finally, from multi-regression analysis of interrupted cutting experimental result, obtained regression equation and it’s coefficient determination was 0.814 and it means that regression equation was predictable. Compared with other continuous cutting, if feed rate increase, surface roughness will grow in interrupted cutting.

CaWO4:Smx(x=0, 0.5, 1.0, 1.5, 2.0mol%) white phosphors with different concentrations of Sm3+ ions weresynthesized using the hydrothermal method. The crystal structure, surface, and optical properties of the CaWO4:Smphosphors were investigated using X-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM),photoluminescence(PL) and photoluminescence excitation(PLE). From the XRD results, the crystal structure of theCaWO4:Sm phosphors was found to be tetragonal. The CaWO4:Sm phosphors became more cohesive with increasing Sm3+-ion concentration. The photoluminescence excitation(PLE) peak of the phosphors, at around 250nm, was ascribed to thetransition from the 1A1 ground-state to the high-vibration level of 1T2 in the WO42− complex. The maximum emissionspectra of the phosphors were observed when the Sm3+ concentration was 0.5mol%. The luminescence intensity of theCaWO4 phosphors was decreased for Sm3+ concentrations greater than 0.5mol%.

In recent years, the construction of high-rise buildings are promoted. According to these, there are many needs about new technologies to strengthen the building performance and high-strength steel is regarded as one of these for promoting building performance. In Korea, high-strength steels which stress are over 600MPa are on market and in aborad, super high-strength steels over 1000MPa are developing and they expected to promote the building performance. But there are still doubts about applying high-strength steel members because of size effect and worry of brittle fracture. In this reports, we propose results of performance and analysis tests for use with general steel. We propose the characteristic of high-strength steels first and next the results of performance test to show they satisfy the performance that designers expect. And last, we compare the results of test and analysis for acquire the alanysis reliability in non-linear analysis with high-strength steels.

In the present study, we systematically investigated the effect of Mn addition on nitrogenation behavior and magnetic properties of Sm-Fe powders produced by reduction-diffusion process. Alloy powders with only single phase were successfully produced by the reduction-diffusion process. The coercivity of powder rapidly increased during nitrogenation and reached the maximum of 637 Oe after 16 hours. After further nitrogenation, it decreased. In contrast, the coercivity of powder gradually increased during nitrogenation for 24 hours. The coercivity of powder was higher than that of powder at the same condition of nitrogenation. It was considered that the Mn addition facilitates the nitrogenation of powder and enhances the coercivity.

Under the huge seismic loads, there are too many risks about which high-rise buildings lost their lateral stiffness caused by plasticity on frame members. Because of earthquake is important cause to bring the collapes countinue to human’s life, many reports examined these phenomenons in various angles. And some of them reported the high possibility about building collapse by deformation concentrations under huge earthquakes. For preventing these phenomenons, researchers suggest some items-such as adding damping devices or strengthen their ductility or stifness. This report suggests choose the method of strengthen building stiffness and suggests the alternative designs using high strength steel-SM570TMC, and provides the results of time-history analysis about the alternative designs for investigation

Glasses were prepared with compositions of (13-x)BaO-80B2O3-7Li2O·xSm2O3, BBLSx(x=0.5, 0.4, 0.3) by melting the starting materials of boron oxide(99.9%), lithium oxide(99.9%), barium carbon oxide(99.9%), and samarium oxide(99.9%) and then quenching the melt at 1350˚C. This led to good-quality BBLSx(x=0.4, 0.3) and poor-quality BBLSx(x=0.5) glasses. The physical and structural properties of the BBLSx glasses were studied by means x-ray diffraction, scanning electron microscopy(SEM), differential scanning calorimetry(DSC), and dielectric spectroscopy. From the x-ray diffraction and SEM results, the quality of the BBLSx glasses significantly depends on the Sm2O3 concentration. The x-ray diffraction pattern showed that the crystallites in the BBLSx glasses after heat treatment at 700˚C may be LiBaB9O15. From the DSC results, the glass transition temperatures(Tg), crystallization temperatures(Tc), and the maximum temperatures of the crystallized(Tp) BBLSx glasses all changed with the Sm2O3 concentration. According to the dielectric spectroscopy results, the values of the real dielectric constant and Tan δ of the BBLSx glasses depended on the Sm2O3 concentration. The values of the real dielectric constant and Tan δ were also shown to depend on the measuring temperature, possibly due to the ion migration in the bulk of the BBLSx glasses.

The preparation of Sm2O3 doped CeO2 in Igepal CO-520/cyclohexane reverse micelle solutions has been studied. In the present work, we synthesized nanosized Sm2O3 doped CeO2 powders by reverse micelle process using aqueous ammonia as the precipitant; hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase, and poly (xoyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by Thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), and Transmission electron microscopy (TEM). The crystallite size was found to increase with increase in water to surfactant (R) molar ratio. Average particle size and distribution of the synthesized Sm2O3 doped CeO2 were below 10 nm and narrow, respectively. TG-DTA analysis shows that phase of Sm2O3 doped CeO2 nanoparticles changed from monoclinic to tetragonal at approximately 560˚C. The phase of the synthesized Sm2O3 doped CeO2 with heating to 600˚C for 30 min was tetragonal CeO2. This study revealed that the particle formation process in reverse micelles is based on a two step model. The rapid first step is the complete reduction of the metal to the zero valence state. The second step is growth, via reagent exchanges between micelles through the inter-micellar exchange.

This study deals with the high frequency induction hardening (HF at 850℃, 120kHz & 50kW condition) SM45C steel. (1) The HF specimen, which was tempered at 150℃, did not show any tempering effect. A brittle fracture occurred at rounded area of the tensile specimen. AE (acoustic emission) amplitude distribution showed between 45dB and 60dB. (2) A slip and fracture occurred at the hole area of the HF specimen which was tempered at 300℃. As they pass the yield point, the AE energy is increased intermittently and AE amplitude distribution exists between 70dB and 85dB. In addition, after imposing the maximum tensile load, AE signals showed high amplitude and energy distribution. The AE amplitude showed between 45dB and 70dB. (3) A brittle fracture occurred at HF specimen which was tempered at 450℃ as if it is torn in the direction of 45° on parallel area over the both sides of the tensile specimen, which lead to several peak appeared in AE energy. It was found that the AE amplitude was relatively low and the AE energy was high.

제품의 품질 불량의 형태는 보통 돌발적 불량과 만성적 불량의 두 가지가 있다. 제품의 경우에 돌발 불량은 보통 치명적 불량으로서 손실이 크지만 그 발생 원인이 명확하고 간단하여 개선이 비교적 용이하다. 그러나 만성불량의 경우는 그 원인이 1~2 가지가 아닌 복수의 조합에 의해 미세하게 만성적으로 발생하여 원인이 명확하지 않아서 많은 개선의 노력에도 불구하고 불량 발생의 재발방지가 어렵다. 이러한 만성불량 개선을 위해서 불량 발생 원인에 대한 물리적인 해석을 통한 과학적인 접근 방법으로 개발한 것이 바로 PM분석이다. 제품 불량과 마찬가지로 서비스의 만족 실패에도 돌발적인 것과 만성적인 것으로 나눠 볼 수 있을 것이다. 일반적으로 서비스 시스템의 개발이나 설계를 위한 서비스 모델링 방법에서 서비스 프로세스의 치명적인 만족 실패에 요인에 대한 것은 그것의 중요도를 평가하여 우선순위를 두어 필수 항목 요인으로 정하여 중점적으로 관리하고 있다. 오늘날 치열한 서비스의 경쟁사회에서는 필수요인의 중점관리만으로는 차별화를 통한 경쟁력의 강화를 꾀할 수 없다. 몇 가지의 사소한 문제의 간과로 인해 고객의 만족도를 저하시킬 수 있으며, 반면에 몇 가지의 사소하지만 세심한 배려로 인해 고객의 만족도 를 극대화 할 수 있다. 본 논문에서는 새로운 서비스 시스템의 설계나 기존 서비스 시스템에서 고객 만족도를 극대화를 통한 서비스의 차별화를 위해서, 설비나 제품의 만성 결함 요인의 제거를 위해 ‘PM 분석’을 개발한 것과 같이 서비스 만족 실패의 만성적 요인의 분석 방법으로 SM 분석방법의 개발과 적용에 대한 제시를 목적으로 하고 있다. SM분석은 서비스 만족도(Service System Satisfaction) 실패 현상의 시스템(System)적인 메카니즘(Mechanism)을 해석하고 이 것의 4M(Man, Method, Material, Machine)과의 연관성을 분석하여 사소하지만 만성적인 실패요인을 찾아 모두 개선하여 서비스 만족도의 극대화를 꾀하는 방법이다. 여기서 중요 단어의 영문 S와 M을 결합하여 SM 분석이라고 명명하였다.

Sm-16.7wt%Co alloy powders were prepared by high energy ball milling under the conditions of various milling time and the content of process control agent (PCA), and their microstructure and magnetic properties were investigated to establish optimum processing conditions. The initial powders employed showed irregular shape and had a size ranging from 5 to . After milling for 5 h, the shape of powders changed to round shape and their mean powder size was approximately , which consisted of the agglomerated nano-sized particles with 15 nm in diameter. The coercivity was reduced with increasing the milling time, whereas the saturation magnetization increased. As the content of PCA increased, the powder size minutely decreased to approximately at the PCA content of 10 wt%. The XRD patterns showed that the main diffraction peaks disappeared apparently after milling, indicating the formation of amorphous structure. The measured values of coercivity were almost unchanged with increasing the content of PCA.

This study investigated tensile deformation of the stress aging heat-treated SM45C steel which are aging temperature at 250℃ and 300℃; aging time at 1 hour and, 3 hours; applied load at 300N and 400N by using an acoustic emission techniques (AEs). A signal processing technology is applied to evaluate an AE source characterization of different AE measurement systems DiSP & PCI-2. In this study, most suitable aging condition appeared at 250℃, 3 hours and 300N. But in cases of 250℃, 3 hours, 400N and 300℃, 3 hours, 400N conditions, yield load decreased compare to other conditions according to the over-aging phenomena. On the other hand, when arranged via AE amplitude results by K-means clustering pattern recognition of AE raw signals, tendency of signal strength appeared non-heat treatment condition, 'Class 1 < Class 2 < Class 3'; optimal condition, 'Class 3 < Class 2'; over-aging condition, 'Class 3 < Class 2 < Class 1'. This is judged by emitting a lot of AE energy when material causes plastic deformation because ductility increases on factor by over-aging phenomenon.

This study is deal with the high frequency induction hardening (HF at 850℃, 120kHz & 50kW condition) SM45C steel. (1) The HF specimen which was tempered at 150℃, did not appear any tempering effect. A brittle fracture occurred at rounded area of the tensile specimen. AE amplitude distribution showed between 45~60dB. (2) The HF specimen which was tempered at 300℃, slip and fracture occurred at the hole area of the tensile specimen. As it passes the yield point, the AE energy increased intermittently and AE amplitude distribution showed between 70~85dB. In addition, after the maximum tensile load, it showed high amplitude and energy distribution. The AE amplitude showed between 45~70dB. (3) The HF specimen which was tempered at 450℃, a brittle fracture occurred as if it is torn in the direction of 45℃ on parallel area over the both sides of the tensile specimen, which led to several peak to be appeared in AE energy. It was found that the AE amplitude was relatively low and the AE energy was high.

To produce alloy powders with only SmFe single phase by reduction-diffusion (R-D) method, the effect of excess samarium oxide on the preparation of Sm-Fe alloy powder during R-D heat treatment was studied. The quantity of samarium oxide was varied from 5% to 50% whereas iron and calcium were taken 0% and 200% in excess of chemical equivalent, respectively. The pellet type mixture of samarium, iron powders and calcium granulars was subjected to heat treatment at 1100 for 5 hours. The R-D treated pellet was moved into deionized water and agitated to separate Sm-Fe alloy powders. After washing them in deionized water several times, the powders were washed with acetic acid to remove the undesired reaction products such as CaO. By these washing and acid cleaning treatment, only 0.03 wt% calcium remained in Sm-Fe alloy powders. It was also confirmed that the content of unreacted -Fe in SmFe matrix gradually decreased as the percentage of samarium oxide is increased. However, there was no significant change above 40% excess samarium oxide.

This paper investigates tensile characteristics of the stress aging heat-treated SM45C steel which are aging temperature at 250℃, 300℃, aging time at 1, 3 hours, and applied load at 300, 400N conditions by using acoustic emission. Most suitable aging condition was aging temperature 300℃, aging time 1 hour, and aging applied load 300N. And increased yield load 28.3% than non-treatment specimen in this condition. AE energy in elastic limit increased about 16.7 times than non-treatment specimen. When aging time is 3 hours, yield load decreased than other conditions that possibility is high to have itself defect on inside the specimen or coarse grain size precipitation is different in happened over-aging phenomenon. Especially, in case of 300℃, 3 hours and 400N condition appeared AE energy in elastic limit fairly high about 30 times than non-treatment specimen. This is considered by emit a lot of energies when material causes plastic deformation because the ductility increases on specimen by over-aging phenomenon.

Lanthanide tantalite (Ln= La, Nd, Sm, Dy, Er and Tm) was synthesized by a solid state reaction between mixed powders of and . The single-phase was prepared by sintering at temperatures of 1423-1673 K in air. The SEM observation showed that the particles were provided with the growth steps and the depeloped facets. The photocatalytic activity for water splitting of prepared was measured under UV light irradiation. The activity obtained was higher than that previously reported. These results suggested the crystallinity of photocatalysts correlates closely with the efficiency of water splitting.