In this study, we fabricate a thin- and dense-BCuP-5 coating layer, one of the switching device multilayers, through a plasma spray process. In addition, the microstructure and macroscopic properties of the coating layer, such as hardness and bond strength, are investigated. Both the initial powder feedstock and plasma-sprayed BCuP-5 coating layer show the main Cu phase, Cu-Ag-Cu3P ternary phases, and Ag phase. This means that microstructural degradation does not occur during plasma spraying. The Vickers hardness of the coating layer was measured as 117.0 HV, indicating that the fine distribution of the three phases enables the excellent mechanical properties of the plasma-sprayed BCuP-5 coating layer. The pull-off strength of the plasma-sprayed BCuP-5 coating layer is measured as 16.5 kg/cm2. Based on the above findings, the applicability of plasma spray for the fabrication process of low-cost multi-layered electronic contact materials is discussed and suggested.

In this study, the effects of Co content on the microstructure and Charpy impact properties of Fe-Cr-W ferritic/martensitic oxide dispersion strengthened (F/M ODS) steels are investigated. F/M ODS steels with 0–5 wt% Co are fabricated by mechanical alloying, followed by hot isostatic pressing, hot-rolling, and normalizing/tempering heat treatment. All the steels commonly exhibit two-phase microstructures consisting of ferrite and tempered martensite. The volume fraction of ferrite increases with the increase in the Co content, since the Co element considerably lowers the hardenability of the F/M ODS steel. Despite the lowest volume fraction of tempered martensite, the F/M ODS steel with 5 wt% Co shows the highest micro-Vickers hardness, owing to the solid solution-hardening effect of the alloyed Co. The high hardness of the steel improves the resistance to fracture initiation, thereby resulting in the enhanced fracture initiation energy in a Charpy impact test at – 40oC. Furthermore, the addition of Co suppresses the formation of coarse oxide inclusions in the F/M ODS steel, while simultaneously providing a high resistance to fracture propagation. Owing to these combined effects of Co, the Charpy impact energy of the F/M ODS steel increases gradually with the increase in the Co content.

본 연구는 일-가정 갈등, 가정-일 갈등이 조직효과성의 주요 변인인 직무만족, 조직몰입, 이직의도에 미치는 영향에 대해 비교 분석하고, 이들 관계에서 정서적 소진의 매개효과를 검증하고자 하였다. 실증연 구를 위하여 조직에서 근무하고 있는 구성원을 대상으로 2019년 6월 1일부터 30일까지 설문조사를 실시하 여 총 136부의 설문지를 수집하였고, SPSS Win 21.0을 활용하여 다음과 같은 결과를 확인할 수 있었다. 첫째, 일-가정 갈등, 가정-일 갈등이 직무만족, 조직몰입에 부(-)적 영향을 미치고, 이직의도에 정(+)적 영향을 미치는 것으로 나타났다. 둘째, 일-가정 갈등이 조직효과성에 미치는 영향에서 정서적 소진의 완전매개효과가 나타났다. 셋째, 가정-일 갈등이 직무만족, 조직몰입에 미치는 영향에서 정서적 소진의 완전매개효과가 나타났으며, 이직의도와의 관계에서는 정서적 소진의 부분매개효과가 나타났다. 향후 측 정 변수에 영향을 미치는 다양한 변수를 고려하고 연구대상을 세분화한 후속 연구가 진행된다면 연구의 이론적 범위를 확장하는데 큰 도움이 될 것이다.

본 논문은 다국적 기업 해외 R&D 자회사의 지식 습득 방향에 있어서 자회사의 글로벌 조직 정체성(global organizational identity)이 미칠 수 있는 영향에 대하여 탐색하였다. 사회 정체성 이론에 근거하여, 본 연구에서는 다국적 기업 해외 R&D 자회사가 본국도 현지도 아닌 그 외의 국가에서 지식을 습득하는 글로벌 지식 습득 행위를 하는데 있어서 해외 R&D 자회사의 글로벌 조직 정체성이 미칠 수 있는 영향에 대해 탐구하였다. 자아 존중감을 향상시키고 불확실성을 감소시키기 위한 목적에서 다국적 기업 해외 R&D 자회사는 자신의 조직 정체성을 일치시키는 방향으로 자신의 태도와 행위를 적합시키게 된다. 사회 정체성 이론에 기초하여, 본 연구에서는 해외 R&D 자회사가 글로벌 혁신가로서 명확한 사명을 가질 때, 보다 높은 자율성을 가질 때, 그리고 글로벌 파트너와의 관계에 보다 깊이 배태되어 있을 때 글로벌 지식 습득 행위를 보다 활발하게 할 수 있을 것이라고 예측 하였다. 그리고 해외 R&D 자회사의 기술적인 역량이 글로벌 조직 정체성 관련 요인들과 글로벌 지식 습득 간의 관계를 강화하는 조절 효과에 관한 가설 또한 수립하였다. 가설 검증을 위해 본 연구에서는 일본 다국적 기업의 해외 R&D 연구소들의 설문 자료와 미국 특허청의 특허 인용 자료를 결합하여 음이항 회귀 모형으로 분석하였다. 실증 분석 결과 해외 R&D 자회사의 자율성과 글로벌 관계에의 배태 정도가 글로벌 지식 습득에 긍정적 영향을 미치는 것으로 나타났으며, 해외 R&D 자회사의 자율성과 글로벌 지식 습득 간의 관계를 자회사의 기술적 역량이 강화하는 것으로 나타났다.

A variety of composite powders having different aluminum and carbon contents are prepared using various organic solvents having different amounts of carbon atoms in unit volume as ball milling agents for titanium and aluminum ball milling. The effects of substrate temperature and post-heat treatment on the texture and hardness of the coating are investigated by spraying with this reduced pressure plasma spray. The aluminum part of the composite powder evaporates during spraying, so that the film aluminum content is 30.9 mass%~37.4 mass% and the carbon content is 0.64 mass%~1.69 mass%. The main constituent phase of the coating formed on the water-cooled substrate is a non-planar α2 phase, obtained by supersaturated carbon regardless of the alloy composition. When these films are heat-treated at 1123 K, the main constituent phase becomes  phase, and fine Ti2AlC precipitates to increase the film hardness. However, when heat treatment is performed at a higher temperature, the hardness is lowered. The main constitutional phase of the coating formed on the preheated substrate is an equilibrium gamma phase, and fine Ti2AlC precipitates. The hardness of this coating is much higher than the hardness of the coating in the sprayed state formed on the water-cooled substrate. When hot pressing is applied to the coating, the porosity decreases but hardness also decreases because Ti2AlC grows. The amount of Ti2AlC in the hot-pressed film is 4.9 vol% to 15.3 vol%, depending on the carbon content of the film.

This study has related to lightweight automobiles due to global warming with the reduction of fossil fuel reserves are rapidly progressing around the automobile industry. This study has revealed the relationship for the mechanical properties via the analyzed microstructure, precipitated phase variation of the wheel hub of a commercial vehicle manufactured using molten forging technology using A356 and A357 alloys, which are high-strength Al-Si-Mg base cast aluminum alloys. Differential scanning calorimetry has performed to analyze the precipitation amount of each alloy that influences the mechanical properties of aluminum alloy. The XRD analysis has measured for the microstructure's crystal phase on A356 and A357 alloys. In this paper has evaluated to compare the properties of the A356 alloy and the A357 alloy for the mechanical properties. The A356 alloy has confirmed that a microstructure is finer than A357 alloy, and a quantity of precipitated material is more than A357 alloy. Therefore, this study confirmed that the A356 alloy has better mechanical properties than the A357 alloy.

본 연구는 수영운동이 백색지방조직의 혈관신생을 조절함으로써 비만을 개선하는지를 조사하였다. 고지방식이를 섭취한 암컷 쥐는 모의 수술 군(Sham), 난소절제 수술 군(OVX) 및 수영운동을 실시한 난소절제 군(OVX + Swim)으로 나뉘었다. Sham에 비해 OVX는 몸무게, 지방조직무게 및 지방세포의 크기가 증가 되었다. 그러나 OVX + Swim의 이러한 요소들(: 몸무게, 지방조직무게 및 지방세포의 크기)은 OVX에 비해 감소 되었다. Sham에 비해 OVX는 백색지방조직에서 혈관신생 촉진인자와 MMPs의 유전자 발현이 증가하였고, 혈관신생 억제인자들의 유전자 발현은 감소하였다. 그러나 OVX + Swim은 OVX에 비해 백색지방조직에서 혈관신생 촉진인자와 MMPs의 유전자 발현이 감소하였고, 혈관신생 억제인자들의 유전자 발현은 증가하였다. 이러한 연구결과들은 고지방식이를 섭취한 난소절제 암컷 쥐에서 수영운동이 백색지방조직의 혈관신생을 억제함으로써 비만을 개선한다는 것을 제시하였다.

This study deals with the yielding behavior and strain aging properties of three bake hardening steels with dualphase microstructure, fabricated by varying the annealing temperature. Bake hardening and aging tests are performed to examine the correlation of martensite volume fraction with yielding behavior and strain aging properties of the bake hardening steels with dual-phase microstructure. The volume fraction of martensite increases with increasing annealing temperature. Roomtemperature tensile test results show that the yielding behavior changes from discontinuous-type to continuous-type with increasing volume fraction of martensite due to higher mobile dislocation density. According to the bake hardening and aging tests, the specimen with the highest fraction of martensite exhibited high bake hardening with low aging index because solute carbon atoms in ferrite and martensite effectively diffuse to dislocations during the bake hardening test, while in the aging test they diffuse at only ferrite due to lower aging temperature.

A 210-day experiment was conducted to examine the effects of starvation on survival, the gonadosomatic index (GSI), hepatosomatic index (HSI), and the intestinosomatic index (ISI), and histological changes in the renal tubule epithelium, midgut epithelium, and hepatocytes in Far Eastern catfish (Silurus asotus). The survival rate decreased to 92.2±0.47% in the fed group and 74.4±2.59% in the starved group during the 210-day experimental period. GSI, HSI, and ISI were lowest in the starved group (p<0.05). The hepatocyte nuclear area, hepatocyte cell area, the nuclear height of the midgut epithelium, and the nuclear height of the kidney were highest in the fed group (p<0.05). The hepatocyte nuclear area, nuclear height of the midgut epithelium, and nuclear height of the kidney were lowest in the starved group (p<0.05). The numbers of melano-macrophages (MMs) found in the kidney cells increased during starvation in this species. This suggests that thinner body cavity regions, the contraction of hepatocyte nuclear sites, and the spreading of kidney cell MMs in this species could be used as alternative indicators for identifying starvation conditions. Therefore, the results from our study provide accurate indications of the nutritional status of Far Eastern catfish.

A commercial AA1070 alloy for electrical wire is severely deformed by drawing process in which a rod with an initial diameter of 9mm into is reduced to a wire of 2mm diameter. The drawn AA1070 wire is then annealed at various temperatures from 200 to 450 oC for 2h. Changes in microstructure, mechanical properties and electrical properties of the specimens with annealing temperature are investigated in detail. The specimen begins partially to recrystallize at 250 oC; above 300 oC it is covered with equiaxed recrystallized grains over all regions. Fiber textures of {110}<111> and {112}<111> components are mainly developed, and {110}<001> texture is partially developed as well. The tensile strength tends to decrease with annealing temperature due to the occurrence of recovery or/and recrystallization. On the other hand, the elongation of the annealed wire increases with the annealing temperature, and reaches a maximum value of 33.3 % at 300 oC. Electric conductivity of the specimens increases with annealing temperature, and reaches a maximum value of 62.6%IACS after annealing at 450 oC. These results are discussed in comparison with those for the other aluminum alloy.

In this study, the effect of tempering on the stretch-flangeability is investigated in 980 MPa grade dual-phase steel consisting of ferrite and martensite phases. During tempering at 300 oC, the strength of ferrite increases due to the pinning of dislocations by carbon atoms released from martensite, while martensite is softened as a consequence of a reduction in its carbon super-saturation. This strength variation results in a considerable increase in yield strength of the steel, without loss of tensile strength. The hole expansion test shows that steel tempered for 20 min (T20 steel) exhibits a higher hole expansion ratio than that of steel without tempering (T0 steel). In T0 steel, severe plastic localization in ferrite causes easy pore formation at the ferrite-martensite interface and subsequent brittle crack propagation through the highly deformed ferrite area during hole expansion testing; this propagation is mainly attributed to the large difference in hardness between ferrite and martensite. When the difference in hardness is not so large (T20 steel), on the other hand, tempered martensite can be considerably deformed together with ferrite, thereby delaying pore formation and hindering crack propagation by crack blunting. Eventually, these different deformation and fracture behaviors contribute to the superior stretch-flangeability of T20 steel.

The directed energy deposition (DED) process of metal 3D printing technologies has been treated as an effective method for welding, repairing, and even 3-dimensional building of machinery parts. In this study, stainless steel 316L (STS316L) and Inconel 625 (IN625) alloy powders are additively manufactured using the DED process, and the microstructure of the fabricated STS316L/IN625 sample is investigated. In particular, there are no secondary phases in the interface between STS316L and the IN625 alloy. The EDS and Vickers hardness results clearly show compositionally and mechanically transient layers a few tens of micrometers in thickness. Interestingly, several cracks are only observed in the STS 316L rather than in the IN625 alloy near the interface. In addition, small-sized voids 200– 400 nm in diameter that look like trapped pores are present in both materials. The cracks present near the interface are formed by tensile stress in STS316L caused by the difference in the CTE (coefficient of thermal expansion) between the two materials during the DED process. These results can provide fundamental information for the fabrication of machinery parts that require joining of two materials, such as valves.

A T-800 (Co-Mo-Cr) coating material is fabricated using Co-Mo-Cr powder feedstock and laser cladding. The microstructure and melted Al erosion properties of the laser-cladded T-800 coating material are investigated. The Al erosion properties of the HVOF-sprayed MoB-CoCr and bulk T-800 material are also examined and compared with the laser-cladded T-800 coating material. Co and lave phases (Co2MoCr and Co3Mo2Si) are detected in both the lasercladded T-800 coating and the bulk T-800 materials. However, the sizes of the lave phases are measured as 7.9 μm and 60.6 μm for the laser-cladded and bulk T-800 materials, respectively. After the Al erosion tests, the erosion layer thicknesses of the three materials are measured as 91.50 μm (HVOF MoB-CoCr coating), 204.83 μm (laser cladded T- 800), and 226.33 μm (bulk T-800). In the HVOF MoB-CoCr coating material, coarse cracks and delamination of the coating layer are observed. On the other hand, no cracks or local delamination of the coating layer are detected in the laser T-800 material even after the Al erosion test. Based on the above results, the authors discuss the appropriate material and process that could replace conventional bulk T-800 materials used as molten Al pots.

베트남의 사회적 기업에 대한 연구는 미국, 유럽에서 주를 이루고 있으며 아시아에서는 아직 미흡한 수준에 이르고 있다. 이에 본 연구에서는 베트남 사회적 기업에 대한 기초연구로써 베트남의 사회변화에 따른 사회적 기업의 조직화 경향을 살펴보고 유형화하는데 초점을 맞추어 향후 후속연구의 기초자료로 활용하고자 하는 목적으로 진행되었다. 연구는 베트남 사회적 기업의 발전을 이끈 역사적 배경과 현재의 맥락에 대해 살펴보고 그에 따른 사회적 기업의 조직화 경향에 대해 분석하였다. 이를 통해 베트남 전역에서 발견할 수 있는 4가지의 광범위한 사회적 기업 모델을 분류하였으며, 구체적으로 협동조합, 사회적 기업가가 설립하고 주도하는 사회적 기업, 전문 중개자가 배양한 사회적 기업, 지역 NGO에서 시작한 변형된 사회적 기업 등으로 구분하였다. 연구결과 조직구성 측면에서 베트남의 사회적 기업은 설립자가 강력하고 중앙 집중적인 의사결정 권한을 가진 장기 이사로 활동하는 것으로 나타났으며, 대부분의 사회적 기 업은 사업 활동 및 개발자금을 포함한 다양한 재정자원을 동원하여 운영비용을 충당하고 있으며, 설립목적을 달성하고 있는 것으로 나타났다. 또한 초기 설립된 일부 사회적 기업을 제외한 기업은 사업을 확장하고 충분한 수입을 확보하기 위해 지속적인 노력을 하는 것으로 나타났다.

주도적 성격과 조직시민행동 간 관계에 대한 관심에도 불구하고, 선행연구들은 일치된 결과를 제공하 고 있지 못하고 있다. 또한 이 관계에 영향을 미치는 사회적 경계조건인 상사와 동료 관계 역시 어떠한 이론적 기반을 통해 가설화하느냐에 따라 상이한 예측이 가능하다. 이에 본 연구에서는 자기향상동기, 특 성활성화이론, 자원보존이론을 기반으로 주도적 성격이 조직시민행동의 참여 정도에 어떠한 영향을 미치는지를 검토하는 하였다. 더 나아가 자원보존이론과 특성활성화이론을 각각 활용하여 상사 지원 수준과 동료의 사회적 태만 정도가 주도적 성격과 조직시민행동에 미치는 효과를 어떻게 조절하는지를 대립가설 로 설정하여 살펴보았다. 특히 본 연구에서는 주도성 자체와 자기향상동기 관련 논의를 바탕으로 주도적 성격을 가진 구성원일수록 조직시민행동이 증가할 것으로 예측하였다. 그리고 특성활성화이론과 자원보존이론을 기반으로 상사 지원과 동료의 사회적 태만 정도가 갖는 상반된 조절효과에 대해 제시하고 대립 가설을 수립하였다. 이를 검증하기 위해 다양한 산업군의 조직에서 근무하는 167명의 상사-조직구성원 설문이 사용되었고, 분석 결과 예측과 같이 주도적 성격은 조직시민행동을 증가시키는 것으로 나타났다. 또한 두 가지 이론들 중 특성활성화이론에 기반한 예측과 같이, 상사 지원이 낮을 때나 동료의 사회적 태만이 높은 경우 주도적 성격을 가진 사람일수록 주도성이 발현되어 오히려 조직시민행동에 보다 활발 히 참여하는 것으로 나타났다. 이러한 연구결과를 바탕으로 결론에서는 조직시민행동에 영향을 미치는 성격적 요인에 대한 추가적인 논의와 채용 및 선발 관점에서 본 연구가 가진 시사점, 그리고 연구의 한계 점과 향후 연구방향을 논의하였다.

The annealing characteristics of cold-rolled Al-6.5Mg-1.5Zn-0.5Fe-0.5Mn alloy, newly designed as an automobile material, are investigated in detail, and compared with those of other aluminum alloys. Using multi-pass rolling at room temperature, the ingot aluminum alloy is cut to a thickness of 4 mm, width of 30 mm, and length of 100 mm to reduce the thickness to 1 mm (r = 75 %). Annealing after rolling is performed at various temperatures ranging from 200 to 500 oC for 1 hour. The specimens annealed at temperatures up to 300 oC show a deformation structure; however, from 350 oC they have a recrystallization structure consisting of almost equiaxed grains. The hardness distribution in the thickness direction of the annealed specimens is homogeneous at all annealing temperatures, and their average hardness decreases with increasing annealing temperature. The tensile strength of the as-rolled specimen shows a high value of 496 MPa; however, this value decreases with increasing annealing temperature and becomes 338MPa after annealing at 400 oC. These mechanical properties of the specimens are compared with those of other aluminum alloys, including commercial 5xxx system alloys.

The objective of this study is to determine the effects of barrel temperature and moisture content on the physicochemical properties of texturized vegetable protein (TVP). The water absorption index, water solubility index, texture, integrity index, color, and scanning electron micrograph of the TVP were analyzed. The extrusion conditions consisted of barrel temperature (110, 130, and 150oC) and moisture content (40, 45, and 50%) at a fixed screw speed of 250 rpm. The TVP extruded at 150oC barrel temperature and bearing 50% moisture content had higher water absorption index and water solubility index. Elastic force, cohesiveness, and color differences were the highest in the TVP extruded at 150oC barrel temperature and possessing 40% moisture content. However, the TVP at 150oC barrel temperature and having 40% moisture content had a lower integrity index than the TVP carrying moisture contents of 45 and 50%. The structure of the TVP extruded at 150oC barrel temperature and having 40% moisture content was found similar to a chicken breast tissue’s structure. In conclusion, 150oC barrel temperature and 40% moisture content are optimal conditional characteristics for the texturization of soy protein isolate and gluten.

Abdominal organs are the most vulnerable body parts under vehicle trauma, and there is high mortality from acute injuries in accidents. There are various ways to reduce this high mortality; one method is Resuscitative Endovascular Balloon Occlusion of the Aorta, which has recently become very popular as a minimally invasive alternative in the emergent management of patients with non-compressible hemorrhages below the diaphragm. However, high safety factor for patients is applied in actual clinical practice because there is no exact standard for the operating time. Therefore, in this study, the effects of the mechanical behavior of organ tissues for the duodenum, kidney, and liver on the operating time of Resuscitative Endovascular Balloon Occlusion of the Aorta is investigated in order to obtain data needed to establish standards of operating time. In characteristic analysis of organ tissues, uniaxial tensile test and compression test are conducted according to the operating time.