Infiltration is a popular technique used to produce valve seat rings and guides to create dense parts. In order to develop valve seat material with a good thermal conductivity and thermal expansion coefficient, Cu-infiltrated properties of sintered Fe-Co-M(M=Mo,Cr) alloy systems are studied. It is shown that the copper network that forms inside the steel alloy skeleton during infiltration enhances the thermal conductivity and thermal expansion coefficient of the steel alloy composite. The hard phase of the CoMoCr and the network precipitated FeCrC phase are distributed homogeneously as the infiltrated Cu phase increases. The increase in hardness of the alloy composite due to the increase of the Co, Ni, Cr, and Cu contents in Fe matrix by the infiltrated Cu amount increases. Using infiltration, the thermal conductivity and thermal expansion coefficient were increased to 29.5 W/mK and 15.9 um/moC, respectively, for tempered alloy composite.

The activation energy to create a phase transformation or for the reaction to move to the next stage in the milling process can be calculated from the slop of the DSC plot, obtained at the various heating rates for mechanically activated Al-Ni alloy systems by using Kissinger's equation. The mechanically activated material has been called “the driven material” as it creates new phases or intermetallic compounds of AlNi in Al-Ni alloy systems. The reaction time for phase transformation by milling can be calculated using the activation energy obtained from the above mentioned method and from the real required energy. The real required energy (activation energy) could be calculated by subtracting the loss energy from the total input energy (calculated input energy from electric motor). The loss energy and real required energy divided by the reaction time are considered the “metabolic energy” and “the effective input energy”, respectively. The milling time for phase transformation at other Al-Co alloy systems from the calculated data of Al-Ni systems can be predicted accordingly.

A lean alloy is defined as a low alloy steel that minimizes the content of the alloying elements, while maintaining the characteristics of the sintered alloy. The purpose of this study is to determine the change in microstructure and mechanical properties due to the addition of silicon or tin in Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys. Silicon- or tin-added F-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P master alloys were compacted at 700 MPa and subsequently sintered under a H2-N2 atmosphere at 1120oC. The sintered density of three alloy systems decreases under the same compacting pressure due to dimensional expansion with increasing Si content. As the diffusion rate in the Fe- P-Mo system is higher than that in the Fe-P-Mn system, the decrease in the sintered density is the largest in the Fe-PMn system. The sintered density of Sn added alloys does not change with the increasing Sn content due to the effect of non-dimensional changes. However, the effect of Si addition on the transverse rupture strengthening enhancement is stronger than that of Sn addition in these lean alloys.

The addition of a large amount of alloying elements reduces the compactibility and increases the compacting pressure, thereby shortening the life of the compacting die and increasing the process cost of commercial PM steel. In this study, the characteristic changes of Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys are investigated according to the Si contents to replace the expensive elements, such as Ni. All compacts with different Si contents are fabricated with the same green densities of 7.0 and 7.2 g/cm3. The transverse rupture strength (TRS) and sintered density are measured using the specimens obtained through the sintering process. The sintered density tends to decrease, whereas the TRS increases as the Si content increases. The TRS of the sintered specimen compacted with 7.2 g/cm3 is twice as high as that compacted with 7.0 g/cm3.

고랭지 감자 재배지에서 진딧물 등 흡즙성 해충에 의한 피해가 약 50% 이상을 차지하고 있으며, 최근 기온이높아지면서 대관령 인근 감자 재배지로 날아오는 진딧물 발생이 늘고 있는 상황이다. 진딧물의 조기 방제를 위해유시충의 동정이 필요하나 유시충의 적절한 분류동정법이 존재하지 않아 분류동정법의 기초자료로써 진딧물의앞날개의 형태계측학을 통한 분석을 하고자 한다. 현재 우리나라에 알려진 감자비래 진딧물 10종 중, Aphis craccivora,Aphis fabae, Aphis gossypii, Rhopalosiphum rufiabdominale의 총 4종의 유시충의 표본에서 앞날개의 사진을 찍어 tpsDig2를이용하여 앞날개 시맥의 Landmarks를 표시하고 PASTsoftware로 각 진딧물의 Landmarks에 대한 주성분분석(PCA,principle component analysis)을 수행하여 분석하였다. 총 4종에 대한 PCA 결과 Rhopalosiphum rufiabdominale은 Aphis속인 3종과 분리되어 차이가 있음을 보였고, Aphis속의 3종간의 PCA 결과 Aphis fabae와 Aphis gossypii는 분리되어구별할 수 있는 것으로 확인되었다. 또한, Aphis craccivora는 위 두 종 사이에 분포되어 있음을 확인할 수 있었다.

최근 기온이 높아지면서 강원도 대관령 감자 재배지로 날아오는 진딧물 발생이 늘어나고 있다. 진딧물은 감자바이러스의 주요 매개체로 감자잎말림바이러스(PLRV)와 감자Y바이러스(PVY)등을 감자에 전염시킨다. 본 연구는 진딧물중 감자에서 가장 발생량이 많은 복숭아혹진딧물(Myzus persicae)의 발생원인 규명과 집단유전학적 군집구조 분석을위한 초위성체마커(microsatellite)를 탐색하고 개발하였다. 집단유전학 분석과 관련된 11편의 논문에서 사용된 총26개의 마커가 탐색되었다. 이중 가장 사용빈도가 높은 총 9개의 마커(M37, M40, M49, M63, myz2, myz9, myz25,S17b, S23)를 최종 선정하였고 증폭 조건을 수립하였다. 이들은 3개의 multiplex PCR set로 집단유전학 분석에 활용할수 있도록 개발하여 향후 집단유전학 연구에 활용하고자 한다

This research focuses on the condition of the coveralls that automobile maintenance workers wear. The objective of this survey is to conduct a thorough analysis on the quality of the coveralls and put forth suggestions for improving their quality. The research data were collected through interviews and the results are as follows. The participants in this research engage in a variety of types of maintenance work including oil changes and overall system checks and they usually wear extra-large-sized coveralls. The coveralls are generally worn during the winter for warmth and the company handles all purchasing and maintenance of the work clothes. Participants mentioned that certain parts of the clothes where they bend and stretch are cumbersome and areas around the knees and arms become easily tainted. They have also reported that although the coveralls are necessary, they are for the most part dissatisfied when it comes to the materials, design, and color. The participants have suggested that new coveralls would help to increase their work efficiency. As a result, it is concluded that the coveralls require much more development to meet the workers’ needs and improvements need to be made on the functionality, aesthetics, and symbolic aspects of the design.

This research focuses on the condition of the coveralls that automobile maintenance workers wear. The objective of this survey is to conduct a thorough analysis on the quality of the coveralls and put forth suggestions for improving their quality. The research data were collected through interviews and the results are as follows. The participants in this research engage in a variety of types of maintenance work including oil changes and overall system checks and they usually wear extra-large-sized coveralls. The coveralls are generally worn during the winter for warmth and the company handles all purchasing and maintenance of the work clothes. Participants mentioned that certain parts of the clothes where they bend and stretch are cumbersome and areas around the knees and arms become easily tainted. They have also reported that although the coveralls are necessary, they are for the most part dissatisfied when it comes to the materials, design, and color. The participants have suggested that new coveralls would help to increase their work efficiency. As a result, it is concluded that the coveralls require much more development to meet the workers’ needs and improvements need to be made on the functionality, aesthetics, and symbolic aspects of the design.

A metallic oxide layer of a heat-resistant element contributes to the high-temperature oxidation resistance by delaying the oxidation and has a positive effect on the increase in electrical resistivity. In this study, green compacts of Fecralloy powder mixed with amorphous and crystalline silica are oxidized at 950oC for up to 210 h in order to evaluate the effect of metal oxide on the oxidation and electrical resistivity. The weight change ratio increases as per a parabolic law, and the increase is larger than that observed for Fecralloy owing to the formation of Fe-Si, Fe-Cr composite oxide, and Al2O3 upon the addition of Si oxide. Si oxides promote the formation of Al2O3 and Cr oxide at the grain boundary, and obstruct neck formation and the growth of Fecralloy particles to ensure stable electrical resistivity.

The Fe-Cr-Al alloy system shows an excellent heat resistance because of the formation of an Al2O3 film on the metal surface in an oxidizing atmosphere at high temperatures up to 1400oC. The Fecralloy needs an additive that can act as a binder because of its bad compactability. In this study, the green compacts of STS434L and Al powder added to Fecralloy are oxidized at 950oC for up to 210 h. Fecralloy and Al is mixed by two types of ball milling. One is vented to air and the other was performed in a sealed jar. In the case of Al addition, there are no significant changes in the electrical resistance. Before the oxidation test, Al oxides are present in the Fecralloy surface, as determined from the energy dispersive spectroscopy results. The addition of Al improves the compactability because of an increased density, and the addition of STS434L increases the electrical resistivity by forming a composite oxide.

A lean alloy is defined as a low alloy steel with a minimum amount of the alloying element that maintains the characteristics of the sintered alloy. It is well known that the addition of elements such as Cr, P, Si, or Mn improves the mechanical characteristics of the alloy, but decreases the sinterability. The mother alloy is used to avoid an oxidation reaction with the alloying elements of Cr, P, Si or Mn. The purpose of this study is to determine the change in the mechanical properties of Fe-P-Mo and Fe-P-Mn alloys as a result of the addition of Si. In this article, the Fe-P-Mo and Fe-P-Mn alloys to which Si is added are compacted at 7.0 g/cm3 and then sintered in H2-N2 at 1120℃. The P around the macropores and large grains reduces due to the formation of SiO2 as the Si content increases. This is caused by the increase in strength owing to reducing intergranular fracture by suppressing the reaction with oxygen.

In order to improve the high-temperature oxidation stability, sintered 434L stainless steel is studied, focusing on the effect of the addition of metallic oxides to form stable oxide films on the inner particle surface. The green compacts of Fecralloy powder or amorphous silica are added on STS434L and oxidized at 950oC up to 210 h. The weight change ratio of 434L with amorphous silica is higher than that of 434L mixed with Fecralloy, and the weight increase follows a parabolic law, which implies that the oxide film grows according to oxide diffusion through the densely formed oxide film. In the case of 434L mixed with Fecralloy, the elements in the matrix diffuse through the grain boundaries and form Al2O3 and Fe-Cr oxides. Stable high temperature corrosion resistance and electrical resistivity are obtained for STS434L mixed with Fecralloy.

This study analyzed the effects of consumers’sense of community regarding outdoor brands on behavioral commitment, purchasing satisfaction, and repurchasing intention and analyzed the effects of behavioral commitment and purchasing satisfaction on repurchasing intention. Additionally, this study analyzed the differences in sense of community, behavioral commitment, purchasing satisfaction, and repurchasing intention according to the types of outdoor consumers’consumption values. A survey was conducted from July 20th to 30th, 2015, and 527 responses were used for the analysis. The results of this study are as follows. First, consumers’sense of community regarding outdoor brands was classified into mutual influences, sufficiency necessity, emotional connectedness, and sense of belonging. Second, outdoor consumers’sense of community had positive impacts on behavioral commitment, purchasing satisfaction and repurchasing intention. Third, outdoor consumers’behavioral commitment and purchasing satisfaction had positive impacts on repurchasing intention. Fourth, there were differences in the outdoor consumers’sense of community, behavioral commitment, purchasing satisfaction, and repurchasing intention according to the types of consumption values. Therefore, outdoor brands can strengthen the relationship with customers considering values and behavior, suggesting the need for a strategy that promotes consumers’sense of community with sustainable management activities that save the environment and local community.

The objectives of this study were to investigate whether heel height changes in the U.S. market occur in a cyclical pattern and heel heights show greater within-year variability over time. Heel height data from U.S. Vogue’s spring and fall editions were analyzed over the time period 1950~2014. A total of 1581 pieces of data were measured in millimeter units using Adobe Illustrator and standardized by dividing the height of the heel by the shoe length through the curved sole line. To analyze the cycle pattern of heel heights, the yearly averages were standardized by using three-year moving average technique to average out the irregular components of time series data and give a better indication of the long-term fluctuation of heel height. To identify the degree of within-year variability of heel height, the standard deviation of the average measurements for a year was calculated, and then decade averages were drawn from the yearly averaged standard deviation. One-way ANOVA was conducted to compare the within-year variability of data in heel height over the time period studied by decade. The results showed: First, there was a trend toward higher heels from the early 1950s to 2011. Second, four cyclical movements of heel height were observed from 1950 to 2007, and heel heights gradually decreased after 2008. Third, the within-year variability significantly increased over time, especially after the 1980s.

As wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anti-corrosion even at high temperature of 800ºC and exhibit corrosion resistance in air. The oxidation behavior and oxidation mechanism of the sintered 316L stainless was reported at the high temperature in our previous study. In this study, the effects of additives on high-temperature corrosion resistances were investigated above 800ºC at the various oxides (SiO2, Al2O3, MgO and Y2O3) added STS respectively as an oxidation inhibitor. The morphology of the oxide layers were observed by SEM and the oxides phase and composition were confirmed by XRD and EDX. As a result, the weight of STS 316L sintered body increased sharply at 1000oC and the relative density of specimen decreased as metallic oxide addition increased. Compared with STS 316L sintered parts, weight change ratio corresponding to different oxidation time at 900oC and 1000oC, decreased gradually with the addition of metallic oxide. The best corrosion resistance properties of STS could be improved in case of using Y2O3. The oxidation rate was diminished dramatically by suppression the peeling on oxide layers at Y2O3 added sintered stainless steel.

Anodic aluminum oxide (AAO) has been widely used for the development and fabrication of nano-powder with various morphologies such as particle, wire, rod, and tube. So far, many researchers have reported about shape control and fabrication of AAO films. However, they have reported on the shape control with different diameter and length of anodic aluminum oxide mainly. We present a combined mild-hard (or hard-mild) anodization to prepare shape-controlled AAO films. Two main parameters which are combination mild-hard (or hard-mild) anodization and run-time of voltage control are applied in this work. The voltages of mild and hard anodization are respectively 40 and 80 V. Anodization was conducted on the aluminum sheet in 0.3 mole oxalic acid at 4oC. AAO films with morphologies of varying interpore distance, branch-shaped pore, diameter-modulated pore and long funnel-shaped pore were fabricated. Those shapes will be able to apply to fabricate novel nano-materials with potential application which is especially a support to prevent volume expansion of inserted active materials, such as metal silicon or tin powder, in lithium ion battery. The silicon powder electrode using an AAO as a support shows outstanding cycle performance as 1003 mAh/g up to 200 cycles.

As well-known wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anticorrosion even at high temperature of 800ºC, and exhibits good corrosion resistance in air. However, when temperature increases above 900ºC, the corrosion resistance of STS begins to deteriorate and dramatically decreases. In this study, the effects of phase and composition of STS on high-temperature corrosion resistances are investigated for STS 316L, STS 304 and STS 434L above 800ºC. The morphology of the oxide layers are observed. The oxides phase and composition are identified using X-ray diffractometer and energy dispersive spectroscopy. The results demonstrate that the best corrosion resistance of STS could be improved to that of 434L. The poor corrosion resistance of the austenitic stainless steels is due to the fact that NiFe2O4 oxides forming poor adhesion between the matrix and oxide film increase the oxidation susceptibility of the material at high temperature.

The purpose of this study was to find whether hemline cycles exist and whether hemlines show greater within-year variability over time. Utilizing US Vogue data from 1950 to 2013 on hemline length of women's daywear, total 2102 day-dresses or skirts on full fashion pictures were analyzed. The skirt length was divided by the total length of figure in the picture which was measured from shoulder to ankle. Aggregated yearly means smoothed by means of three-point moving averages were used to provide a better indication of the long-term direction of movement of the hemline. Within-year hemline variability was smoothed by the way of three-point moving average as well. The data showed five cycles on hemline change processes. The first cycle took 21 years from 1950 to 1971, which was the longest period and had the biggest hemline changes. The second cycle was the shortest from 1971 to 1977, in which hemline moved between below-knee length and midcalf. The hemline in the third cycle moved between midcalf and miniskirt. The third cycle took 16 years from 1977 to 1993. The forth was a short cycle from 1998 to 2001, and hemlines moved moderately between below-knee length and above-knee length. The fifth cycle has been on going since 2001, and the hemline has been getting longer after 2007. The within-year variability of hemlines was bigger in 1980s than previous years and was steadily increased.