Critical assessment of Pt surface energy – An atomistic study

Kim, Jin-Soo,Seol, Donghyuk,Lee, Byeong-Joo Elsevier 2018 Surface science Vol.670 No.-

<P><B>Abstract</B></P> <P>Despite the fact that surface energy is a fundamental quantity in understanding surface structure of nanoparticle, the results of experimental measurements and theoretical calculations for the surface energy of pure Pt show a wide range of scattering. It is necessary to further ensure the surface energy of Pt to find the equilibrium shape and atomic configuration in Pt bimetallic nanoparticles accurately. In this article, we critically assess and optimize the Pt surface energy using a semi-empirical atomistic approach based on the second nearest-neighbor modified embedded-atom method interatomic potential. That is, the interatomic potential of pure Pt was adjusted in a way that the surface segregation tendency in a wide range of Pt binary alloys is reproduced in accordance with experimental information. The final optimized Pt surface energy (mJ/m<SUP>2</SUP>) is 2036 for (100) surface, 2106 for (110) surface, and 1502 for (111) surface. The potential can be utilized to find the equilibrium shape and atomic configuration of Pt bimetallic nanoparticles more accurately.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pt surface energy is calculated by interatomic potential that reproduces the surface segregation in eight Pt-binary alloys. </LI> <LI> The finally optimized Pt surface energy is 2036, 2106 and 1502 mJ/m<SUP>2</SUP> for the (100), (110) and (111) surfaces, respectively. </LI> <LI> The optimized surface energy is one of the most accurate ones among those reported during the last 40 years. </LI> <LI> We propose our computational procedure as an evaluation tool for surface energy of elements. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

태양열 흡수체용 구리산화막의 표면특성 및 저방사코팅 연구

강동필(Kang Dong-Pil),박효열(Park Hoy-Yul),나문경(Na Moon-Kyong),안명상(Ahn Myeong-Sang),이태주(Lee Tae-Joo),장태순(Jang Tae-Soon),이종엽(Lee Jong-Yup),김춘열(Kim Chun-Yeol) 한국태양에너지학회 2006 한국태양에너지학회 학술대회논문집 Vol.- No.-

This study was done on surface property of surface-oxidized copper for solar absorber and low emissivity coated on solar absorber. As surface temperature of solar energy absorber increases, most solar energy absorbers emit the energy into infrared rays. For increasing the efficiency of collecting sun energy, low emissivity coating on solar energy absorber is needed. Temperature elevation characteristics of solar energy absorber was influenced by surface condition of solar energy absorber and low emissivity coating material.<br/> Surface-oxidized coppers were prepared for solar energy absorber. The temperature elevation property of surface-oxidized copper absorber was examined with several insulation conditions to minimize the heat loss through conduction and convection. Two kinds of low emissivity materials and silica sol were coated on the surface-oxidized copper absorber. And then the surface properties, surface condition and roughness, were observed. Temperature elevation characteristics of solar energy absorber was influenced by surface condition of solar energy absorber and low emissivity coating material. Thin and uniform surface of low emissivity coating can reduce the emission of thermal energy.

표면처리가 치과용 콤포짓트 레진의 표면자유에너지에 미치는 영향

박원종(Won-Jong Park),최재윤(Jae-Yoon Choi),안진수(Jin-Soo Ahn),이상훈(Sang-Hoon Rhee),양형철(Hyeong-Cheol Yang),임범순(Bum-Soon Lim) 대한치과재료학회 2010 대한치과재료학회지 Vol.37 No.3

The purpose of this study was to evaluate the surface free energy of composite resin with different surface treatments. Six commercially available composite resin (Z250, P60, Metafil CX, Heliomolar, Grandio, and Supreme XT) were tested. The surface free energy of composite resin after various surface treatments was measured, and correlation between the types (microhybrid, microfilled, and nanohybrid) of composite resin and the surface free energy was evaluated. The surface of specimen was polished with SiC paper in order of #2000, #1000, and #600, respectively, and sandblasted with alumina (50 ㎛). Using 3 different liquids (deionized water, formamide and 1-bormo-naphathlene), the contact angles of resin were measured with Image analyzer, including the non-treated surface (control). The surface free energy of each specimen was calculated using Li fshitz-van der waals/aci d-base (LW/AB) method. Results were statistically analyzed using Turkey multiple comparison test (p=0.05). The surface free energy of composite resin was increased significantly compared to the energy before the surface treatment (p<0.05). The surface free energy of nanofilled composite resin showed significantly lower value compared to resin with other types of fillers, in non-treated surfaces. When the surface was treated, the surface free energy of nanofilled composite resin showed higher tendency than other resins with different types of fillers.

행동적 진실성이 표면행동 및 내면행동에 미치는 영향: 관계적 에너지의 매개효과 및 도덕적 정체성의 조절효과

서지민,손승연 한국인적자원개발학회 2024 인적자원개발연구 Vol.27 No.2

우리는 조직 생활에서 다양한 사람과의 상호작용 속에서 업무를 수행하며, 이러한 과정에서 감정을 관리하는 것은 필수적이다. 또한 조직에서의 역할은 본질적으로 사회적 기대의 묶음(bundle)으로 역할 수행 중에 감정을 불가피하게 경험하게 된다. 이처럼 감정노동은 사람이 하는 일에 있어 필연적으로 요구되는 것이라 할 수 있다. 감정노동 연구 초기에는 감정노동이 구성원들에게 미치는 부정적인 영향에 주목하였으나, 감정노동전략 중 표면행동보다는 내면행동을 유도함으로써 감정노동의 긍정적 영향을 높일 수 있다는 연구 결과가 밝혀지면서 이들의 선행변수를 탐색하는 연구가 요구되어 왔다. 본 연구는 이러한 연구의 필요성을 바탕으로 다음의 3가지 목적을 가지고 수행되었다. 첫째, 표면행동과 내면행동에 영향을 미치는 요인으로 심리적 자원인 관계적 에너지의 역할을 확인하는 것이다. 둘째, 관계적 에너지를 촉진할 수 있는 리더의 행동으로 리더의 행동적 진실성을 제시하고, 관계적 에너지의 매개 역할을 검증하는 것이다. 셋째, 행동적 진실성이 관계적 에너지를 통해 표면행동과 내면행동에 미치는 영향력 과정에서 도덕적 정체성의 조절 효과를 검증하는 것이다. 이를 위해 육군 간부를 대상으로 2주의 시차를 두고 설문조사를 실시하였으며, 228부의 자료를 토대로 분석을 실시하였다. 분석 결과, 행동적 진실성과 관계적 에너지의 정적 관계를 확인하였으며, 관계적 에너지는 표면행동과는 부적, 내면행동과는 정적 관계가 있는 것으로 나타났다. 또한, 관계적 에너지는 행동적 진실성과 표면행동, 내면행동의 관계를 매개하였으며, 행동적 진실성이 관계적 에너지를 경유하여 표면행동과 내면행동에 미치는 간접효과는 도덕적 정체성이 높을 때 강화되는 것을 알 수 있었다. 본 연구는 감정노동전략의 선택에 있어 심리적 메커니즘을 실증함으로써 기존 문헌을 확장하는 이론적 기여와 감정노동전략과 관련한 실무적인 함의를 제시하고 있다. In organizational life, performing tasks involves interacting with diverse individuals, and it is essential to manage emotions in this process. In addition, within the organizational roles, emotions are inevitably experienced as roles are essentially bundles of social expectations. Thus, emotional labor can be considered an inevitable requirement in work involving people, and there is a growing need for research exploring the antecedents of these strategies. Based on the need for such research, this study was conducted with the following three purposes. First, it is to identify the role of relational energy, a psychological resource, as a factor that affects surface acting and deep acting. Second, it is to present the leader's behavioral integrity as a leader's behavior that can promote relational energy, and to verify the relationship between behavioral integrity and relational energy and the mediating role of relational energy. Third, it is to verify the moderating effect of moral identity in the process of behavioral integrity on surface acting and deep acting through relational energy. To this end, a survey was conducted in military settings with a time lag of two weeks, and the collected data from 228 responses were analyzed using hierarchical regression analysis and SPSS macro. As a result of the analysis, behavioral integrity had a positive relationship between relational energy, and it was found that relational energy had a negative relationship with surface acting and a positive relationship with deep acting. In addition, relational energy mediated the relationship between behavioral integrity and surface acting, deep acting, and as a result of verifying the moderated mediating effect, the indirect effect of behavioral integrity on surface and deep acting through relational energy was strengthened when moral identity was high. In the discussion section, the contributions and limitations of this study were addressed.

스피넬 페라이트의 비이완 표면에너지 계산

신형섭,손정호,Shin, Hyung-Sup,Sohn, Jeongho 한국재료학회 2015 한국재료학회지 Vol.25 No.12

A new method is proposed for the calculation of the unrelaxed surface energy of spinel ferrite. The surface energy calculation consists of (1) setting the central and computational domains in the semi-infinite real lattice, having a specific surface, and having an infinite real lattice; (2) calculation of the lattice energies produced by the associated portion of each ion in the relative domain; and (3) dividing the difference between the semi-infinite lattice energy and the infinite lattice energy on the exposed surface area in the central domain. The surface energy was found to converge with a slight expansion of the domain in the real lattice. This method is superior to any other so far reported due to its simple concept and reduced computing burden. The unrelaxed surface energies of the (100), (110), and (111) of $ZnFe_2O_4$ and $Fe_3O_4$ were evaluated by using in the semi-infinite real lattices containing only one surface. For the normal spinel $ZnFe_2O_4$, the(100), which consisted of tetrahedral coordinated $Zn^{2+}$ was electrostatically the most stable surface. But, for the inverses pinel $Fe_3O_4$, the(111), which consisted of tetrahedral coordinated $Fe^{3+}$ and octahedral coordinated $Fe^{2+}$ was electrostatically the most stable surface.

표면 에너지가 물 윤활 현상에 미치는 영향에 대한분자시뮬레이션 연구

김현준 한국트라이볼로지학회 2023 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.39 No.6

This paper presents a molecular dynamics simulation-based numerical investigation of the influence of surface energy on water lubrication. Models composed of a crystalline substrate, half cylindrical tip, and cluster of water molecules are prepared for a tribological-characteristic evaluation. To determine the effect of surface energy on lubrication, the surface energy between the substrate and water molecules as well as that between the tip and water molecules are controlled by changing the interatomic potential parameters. Simulations are conducted to investigate the indentation and sliding processes. Three different normal forces are applied to the system by controlling the indentation depth to examine the influence of normal force on the lubrication of the system. The simulation results reveal that the solid surface's surface energy and normal force significantly affect the behavior of the water molecules and lubrication characteristics. The lubrication characteristics of the water molecules deteriorate with the increasing magnitude of the normal force. At a low surface energy, the water molecules are readily squeezed out of the interface under a load, thus increasing the frictional force. Contrarily, a moderate surface energy prevents expulsion of the water molecules due to squeezing, resulting in a low frictional force. At a high surface energy, although squeezing of the water molecules is restricted, similar to the case of moderate surface energy, dragging occurs at the soil surface–water molecule interface, and the frictional force increases.

플라즈마 표면처리가 표면에너지와 Cr코팅층 / 기판의 부착 특성에 미치는 영향

김동용 ( Dong Yong Kim ),정은욱 ( Eun Wook Jeong ),후이 ( Kwun Nam Hui ),최영선 ( Young Son Choe ),한정호 ( Jung Ho Han ),조영래 ( Young Rae Cho ) 대한금속재료학회(구 대한금속학회) 2013 대한금속·재료학회지 Vol.51 No.10

Atmospheric plasma surface treatment (APST) was applied on the soda-lime glass and silicon wafer(Si-wafer) substrates for surface modification. The surface energy for the surface treated samples was measured using the wetting angle. The effect of APST on surface energy and interface properties between sputtered chromium (Cr) coatings and substrates was investigated. The surface energy increased linearly and reached a maximum value of 74 mJ/m2 by APST. The increase in surface energy is due to the increased value of the polar component in surface energy. When the samples were exposed to the air, the increased surface energy decreased and tended to have hydrophobicity. The work of adhesion for the surface treated samples was calculated using the data of surface tension for water. We demonstrated that the trend of work of adhesion for the samples was similar to the change of adhesion strength between sputtered Cr coatings and the surface treated substrates. (Received March 13, 2013)

Study of the wetting characteristics of water droplet on a heterogeneous pillared surface

고정안,권태우,매튜스탠리암브로시아,하만영 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.3

We investigated the wetting characteristics of a water droplet on a heterogeneous pillared surface at the nano-scale including contactangle, molecule inflow percentage and density fields and compared them with the wetting characteristics of a water droplet on a homogeneouspillared surface. Molecular dynamics simulations were employed to analyze the wetting behavior of water droplets on surfaceswith pillar structures by considering different potential energies including bond, angle, Lennard-Jones and Coulomb to calculate the interactingforces between water molecules and the surface. The heterogeneous surfaces considered had pillars with a different surfaceenergy than the base surface. It was found that the difference in surface energy between the base surface and pillar had little effect on thehydrophobicity of the surface at low pillar heights. However cases with pillar heights over H = 4.24 Å, the pillar surface energy has alarger effect on the molecule inflow percentage with the maximum differences in the range from 33.8% to 47.2% depending on the basesurface energy. At a pillar height of H = 16.96 Å, the pillar surface energy has a large effect on the contact angle of the water droplet withthe maximum differences in the range from -26.1% to -40.62% depending on the base surface energy. There was a large variation in thecontact angle of the droplet as the pillar height increased when there was a large difference in the surface energies between the base andthe pillars.

보문 : 자기세정산업용 소재 개발을 위한 O2 플라즈마 처리가 Poly(imide) 필름의 표면 형태 및 특성에 미치는 영향

강인숙 ( In Sook Kang ) 한국의류학회 2012 한국의류학회지 Vol.36 No.10

This study was a preliminary study to investigate the influence of surface morphology and characteristics on the self-cleaning of substrates. PI film was treated by O2 plasma to modify the surface; in addition, AFM and Fe-SEM were employed to examine the morphological changes induced on a PI film treated by O2 plasma and surface energies calculated from measured contact angles between several solutions and PI film based on the geometric mean and a Lewis acid base method. The surface roughness of PI film treated by O2 plasma increased with the duration of the O2 plasma on PI film due to the increased surface etching. The contact angle of film treated by O2 plasma decreased with the increased treatment time in water and surfactant solution; in addition, the surface energy increased with the increased treatment times largely attributed to the increased portion on the polar surface energy of PI film. The coefficient of the correlation between surface roughness and surface polarity such as contact angle and surface energy was below 0.35; however, it was over 0.99 for the contact angle and surface energy.

First-Principles Study of the Surface of Wurtzite ZnO and ZnS - Implications for Nanostructure Formation

나성호,박철홍 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.2

The microscopic properties of several ZnO and ZnS surfaces of low Miller index are investigated through first-principles calculation of the surface energy, crystal structure and electronic structure. Generally, the non-polar surfaces such as (1010) and (1120) are found to be more stable than the polar (0001)-Zn surface. The (1120) surface is found to be the most stable for both ZnO and ZnS semiconductors and the (1010) surface is found to have a slightly larger surface energy. These are consistent with the abundant observations of ZnO nanostructures having (1120) and (1010) surfaces. The near-surface structures and electronic structures are discussed. The microscopic properties of several ZnO and ZnS surfaces of low Miller index are investigated through first-principles calculation of the surface energy, crystal structure and electronic structure. Generally, the non-polar surfaces such as (1010) and (1120) are found to be more stable than the polar (0001)-Zn surface. The (1120) surface is found to be the most stable for both ZnO and ZnS semiconductors and the (1010) surface is found to have a slightly larger surface energy. These are consistent with the abundant observations of ZnO nanostructures having (1120) and (1010) surfaces. The near-surface structures and electronic structures are discussed.