Topological data analysis has recently been applied to various research fields. Persistence Diagram (PD) is a visualization of it and expresses the features of holes (ring and cavity) embedded in the data as two-dimensional scatter plots. By using PDs, we have developed the method to characterize microscopic structure obtained by the molecular dynamics (MD) simulation. In this presentation we first introduce how to take the geometric information from the PDs based on some typical structures. Then, we introduce the character of PDs for bulk system obtained by the MD simulation. Namely, atomistic configurations for the ideal gas (uniform random), the face-centered cubic crystals with and without thermal noise, and Lennard-Jones liquid are considered. Finally, we introduce the application of PD for the atomistic configuration of glassy solid. There, we introduce that PDs can give a unified view for the various medium-range order structures.

Material simulation for amorphous materials have a difficulty because there are few empirical potentials to represent its random bonding states and its large-scale structure including middle-range order is hard to apply the first-principles simulation directly. In this presentation, we demonstrate that the machine learning potential, which has been actively researched in recent years, is effective for theoretical calculation of amorphous materials, and show its construction way and applications.

Active learning or Bayesian optimization are often used to fit a function or optimize an objective function when the data aquisition cost is not negligible. We introduce these two concepts with minimum prior knowledge on informatics.

In this talk, we introduce catalytic reaction prediction by sparse modeling as one of the practical cases of materials informatics. Specifically, we use sparse modeling to solve the regression problem, which uses the phosphoric acid catalyst used for the reaction in the epoxidation of olefins as input, and outputs the experimental results of the reaction yield. The information of charge and vibration mode are used as descriptors of phosphoric acid catalyst using first principle calculation. We introduce the result of the case of 14 experimental data.

Solid surfaces play crucial roles in hydrogen technology such as hydrogen storage, ortho-para conversion in liquefaction, and photocatalytic H2 generation. A key in these processes is diffusion of hydrogen near the surfaces. Focusing the diffusion of hydrogen at metal and metal oxide surfaces, control of absorption/desorption by surface modification, quantum diffusion at low temperature, and the effects of electron localization on diffusion are reported.

Since titanium is a low activation material, it is used as a material of a beam pipe in high power beam accelerator. Because the titanium surface is normally covered with an oxide film, it has no getter function. However, if the oxide film is removed, the beam pipe itself should be able to be used as a vacuum pump. We will report on the method and development status of using a titanium vacuum vessel as a beam pipe.

A new form of pump AGNEG (Atomized granule non-evaporable getter) -Pump was developed by making NEG powder by non-contact atomization method and enclosing it in a fine wire mesh container. The atomization method can produce a powder close to a true sphere, so it may be possible to obtain new knowledge as a pump element. The material of the NEG element is a ternary alloy of ZrVFe The particles 75—200 μm NEG particles are used to report the measurement results of the exhaust velocity of H₂, CO, N₂ etc.

An operand desorption gas analysis system was developed. The advantage of this system is that it enables a desorption gas analysis of an operating device under an approximately atmospheric pressure (0.1 to 0.2 MPa) using gas chromatography/mass spectrometry. In the invited talk, some measurement examples (DC electric motor and capacitor) using this operand gas analysis system are explained.

Gas molecular flow in steady state through long uniform ducts are well described with classical diffusion theory. The diffusion constants of the flow are expressed using the mean free path L and mean square of its componet of axial direction x^2>. In this presentation, the Green function of one dimensional diffusion theory and the result of Monte-Carlo simultion for the molecular flow in non-staedy state are compared and the limit of application of diffusion theory are discussed.

When operating a dry vacuum pump in a semiconductor manufacturing process, fine particles may be mixed simultaneously with the inflow of a process gas. In order to avoid that these particles adversely affect the pump operating time, it is necessary to devise the rotor and casing shape and effectively discharge the particles. Numerical analysis is used to carry out this shape study. In this presentation, we report the conducted numerical analysis for the gas flow and the particle behavior in the dry vacuum pump.

Calculating the flow rate through the cylindrical tube from the upstream and downstream pressures was difficult becase the characteristics of the gas flow changes depening on the pressure and so on. We propose a novel calculation method applicable to whole flow regime by linking their equations including from molecular flow to intermediate flow, viscous-laminar flow, turbulent flow, critical flow, and subcritical flow. The calculation results are consistent with the previous results obtained by experimental/DSMC within 30 %.

Friction coefficient of solid lubricants increases due to oxidation in air, in oil, especially under harsh condition of high-temperature. Harmless zinc oxide coating is a strong candidate to solve this problem because of the possible stable crystal structure under harsh condition. Friction coefficient of zinc oxides known so far is too large to be used as lubricative coatings. We have successfully reduced the friction of zinc oxide coatings by controlling crystal preferred orientation The bearing system with installed ZnO coated balls shows about half lower friction than the bearing system without ZnO coated balls and the small size gas turbine generator system installed with ball bearing coated with ZnO can also successfully improve energy efficiency up to more than a percentage.

The outgassing rate of a lean duplex stainless steel after ordinary baking process was a 10^-12 Pam³s^-1m^-2 . This value was decreased approximately two digits in comparison with that of austenitic stainless steel SUS304L. The outgassing property of a lean duplex stainless steel is discussed in presentation.

Nepenthes pitcher-plant-inspired Liquid-Impregnated Surfaces (LIS) has attracted much attention because of their transparency and antifouling performance against low surface tension liquids, which have been difficult to achieve with conventional superhydrophobic surfaces. Here, a slippery smooth LIS coating was applied to the tribology field, which has been discussed only in relation to liquid. The surface produced has excellent transparency, antifouling property, and low friction property (average coefficient of friction: 0.05), and it can indicate the possibility of realizing an ultra-smooth surface that easily slides down various solid materials.

We worked on the development of matte-black coating that formed roughness on the electroless plating coating surface for low light reflection.This matte-black coating had various problem in ultra high vacum such as optical parts of KAGRA.In this presentation, we report the improvement effect that composite Tungsten to electroless plating and heat treatment in vacum.Futhermore, we introduce this black coating applied to example other than optical parts of KAGRA, and properties requires.

Influence of Acetic Acid which is one of the corrosive impurities in fuel grade bioethanol on tribological characteristics of metal based materials such as iron and titanium under ethanol lubrication was invetigated. Wear mechanisms of the tested materials were discussed based on the friction coefficient, the wear volume and the morphplogy and chemical composition of worn and unworn surfaces.

Since the lifetime of the OLED device decreases in proportion to the amount of impurities, it is an important issue to secure the cleanliness of the device for prolonging the lifetime. It is said that the water-soluble impurities used in the surface treatment and the cleaning process remain in the chamber and affect the lifetime of the OLED element. This time, we report the method of collecting water-soluble impurities from a vacuum chamber, the method of evaluating residual ions using ion chromatography, and its examples.

The micro arc oxidation(MAO) process was developed for vacuum equipment using corrosive gas such as CVD equipment, and its characteristics were evaluated.The oxide film cross section of the MAO treatment had a three layer structure and was a crystalline oxide film. MAO treated oxide film were not detected except the elements derived from the base material. The amount of outgassing from MAO treatment was 1/10 less compared from sulfuric acid alumite , and mainly low in water.

In various electrocatalysts, cathode catalysts for polymer electrolyte fuel cells driving oxygen reduction reaction have been actively investigated and various methods have been already established. Here, I would like to introduce our recent experimental results at Pt alloy nanostructured electrocatalysts and bio-inspired multi-metal and nitrogen-codoped carbon catalysts by X-ray absorption fine structure (XAFS), soft X-ray absorption spectroscopy (XAS) and surface enhanced infrared absorption (SEIRA) spectroscopy.

In surface enhanced Raman scattering, incident photons are scattered not only by molecular vibrations but also by conduction electrons of a metal substrate. In this talk, we demonstrate in-situ observation of electrochemical interfaces using both scattering processes.

Vibrational sum frequency generation is one of the second order nonlinear spectroscopies and provides unique inherent interface selectivity. In particular, heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy enables us to measure not only the intensity but also the phase of the signal light. HD-VSFG has been successfully applied to simple interfaces such as gas/liquid and transparent solid/liquid interfaces, and it has revealed substantial new knowledges about the structure and dynamics at the interfaces. However, it has been difficult to realize HD-VSFG measurements at buried electrode/electrolyte solution interfaces. In the present study, we develop an in-situ reference method which realizes HD-VSFG measurements at electrode/electrolyte solution interfaces. Orientation of solvent molecules at Pt electrode/acetonitrile solution interfaces will be discussed based on the HD-VSFG measurements.

We investigated the molecular behavior of metal ions in BMI-TFSA close to the electrode under cathodic applied potential using originally developed scanning electrochemical XPS (Scanning EC-XPS) and conventional electrochemical measurements. By the analysis of XPS data and the numerical simulation, we revealed that the metal ions diffused by the hopping-like mechanism, in which the apparent diffusion coefficient increased with increasing of the concentration of 'holes' (vacancies formed between IL molecules) acting as hopping sites. We also revealed that the applied potential dependence of the molecular arrangement of IL molecules on the electrode.

Direct observation of structural changes provides invaluable information about charge transfer, ionic diffusion, and side reactions in electrochemical reaction processes. X-ray surface diffraction and neutron reflectometry are powerful techniques for gaining a nanoscopic understanding at solid/liquid interfaces as a function of the depth. We will report the interfacial structures changes during the electrochemical cycling and discuss on the crucial structure-parameters which determine the stability and the reaction rate in the interfacial regions. The depth-profile of the interfacial structures could give insight into research directions for electrode materials with highly-functional interfaces.

We introduce an analysis method of carbon materials, especially graphene oxide (GO), by X-ray photoelectron spectroscopy (XPS). It is possible to evaluate not only oxygen-containing functional groups but also oxygen-free carbon functional groups from C1s spectra. Data comparison of XPS with other analytical methods such as FT-IR, Raman, NMR is shown. In addition, with regard to graphene oxide, the relationship between oxygen functional groups and characteristics is also introduced.

The polymer electrolytes for fuel cells are membraned on SiO₂ and used as 5-nm thick binders on C-supported Pt catalysts. The three-dimensional structures in those materials are unknown and needed for the further improvement of the power generation and durability of fuel cells. We developed an in situ neutron-reflectometry method employed at high temperature and humidity. The internal structures of the polymer electrolyte thin films on SiO₂, Pt, C were understood to be different under power generation conditions. The water distributions were also very different up to 100 nm on different substrates.

Recently, development of oxygen evolution catalysts has received attractive attention toward the achievement of hydrogen production by electrochemical water splitting. In this work, we observed all element in the cobalt carbonate catalyst by some kinds of operando observation technique for X-ray absorption and infrared absorption spectroscopy. As the result, it was suggested that the CoO₂ structure of active species for water splitting was generated on the catalyst surfaces by covering with carbonate anions. In this presentation, I will talk about the resent results of oberando observation for oxygen evolution electrocatalysts.

These days, hydrogen gains the greatest attention to replace a fossil fuel from political and business circles due to its renewability and low environmental load. However, in such advantage, there is a large barrier that water splitting reaction powered by electricity is so bad ineffective because of high overvoltage on the oxygen generating electrode. So, development of high activity Oxygen evolving catalysts (OECs) are required. In this presentation, we are going to talk about the relationship between adsorbed anions and reaction activity on the surface of OECs by operando observations.

Simultaneous measurement of Quick Scanning X-ray absorption fine structure (QXAFS) spectroscopy and Mass spectroscopy (MS) was applied to In catalysts for highly active methane conversion reaction during the activation processes and under the reaction conditions(1173 K, 1 bar CH₄ flow). The In catalysts deposited on SiO₂ and ZSM-5 were analyzed. We found the completely different behavior during the activation processes between two supports. In the In /SiO₂ we found the metallic In particles which showed dynamic structure change during the activation processes while In/ ZSM-5 were present in small In species which were reduced during the activation processes. We will discuss the structure -activity relation in the talk.

We investigated the relationship between the band-offset, the gate leakage current, and the interface states density on SiO₂/4H-SiC (000-1) structures via hard x-ray photoelectron spectroscopy and electrical measurements. We found that valence band-offset (ΔEv) was larger than conduction band offset (ΔEc), indicating that electron tunneling was more predominant than hole tunneling. SiO₂ prepared by a dry (wet) oxidation procedure exhibited the highest (lowest) gate leakage current onset and the highest (lowest) interface states density and the largest (smallest) ΔEc. These results were related to hydrogen atoms and carbon related defects at the SiO₂/4H-SiC (000-1) interface.

In order to study the surface of nano structures, we have combined a scanning electron microscopy (SEM) and the electron diffraction, i.e. Weissenberg reflection high energy electron diffraction (W-RHEED). In W-RHEED, hundreds of RHEED patterns are acquired as a function of the sample rotation angle. The surface structure can be analyzed using 3D reciprocal maps reconstructed from the patterns. When the nano-beam is used, we will obtain the surface structure of a small area. We will report the improvement of the apparatus to measure smaller area.

The helium ion microscope (HIM) is similar to a scanning electron microscope (SEM), but it can obtain high magnification images even with a large working distance, a low depth of field, and low ion irradiation. Because of such advantages, it is used to observe samples that are difficult to observe by the SEM. However, the image contrast of HIM and SEM are not the same. We observed and compared HIM and SEM images of various materials under the same conditions.

Based on the multiple scattering theory, RHEED intensities are calculated from H adsorbed on Ni(111) surfaces. The calculated intensities show systematic variations as a function of H position both in the surface normal and parallel directions under some diffraction conditions. RHEED intensities also change as a function of depth when H atoms exist in the subsurface region. The results show that RHEED intensity analysis can be used to extract the structural information of H atom on a surface, which was difficult in LEED and surface X-ray diffraction.

Tensile deformation of carbon fiber reinforced plastics (CFRPs) along the fiber direction were performed, followed by fracture. Residual epoxy resin chips on the carbon fibers were observed by transmission electron microscopy to consider the fracture mechanism.

The exfoliation behavior of resin matrices bonding on carbon fiber surfaces was observed in situ by transmission electron microscopy during the tensile deformation of carbon fiber reinforced plastics along the direction tilted by 45° from the fiber direction.

To investigate the laser processing surface texture at the atomic level, we developed a near-infrared laser emission equipment incorporated into a transmission electron microscope. We selected high-melting-temperature metals for processing and irradiated the laser at various conditions, e.g., the intensity, pulse width, and scanning speed, followed by the observation of the surface texture.

Soft X-ray absorption spectra of 750-nm thick polyester films were measured with the transmission and total electron yield (TEY) methods. In the OK region, OK-XANES were successfully measured with the transmission mode, because soft X-rays can sufficiently transmit the 750-nm thick films. However, in the CK region, CK-XANES exhibited saturated profiles, because soft X-rays cannot sufficiently transmit the films.

A novel technique of X-ray standing wave imaging was newly developed for investigating the impurity depth profiles at all different parts of a nanolayer material. For only one sample, the technique produces large amounts of experimental data and one piece of data encodes the impurity depth profile at one part. It is extremely laborious to process the data one by one. For this reason, the present paper proposes an efficient data handling method of feature mapping. It extracts the key feature of every piece of data and displays all of them in one feature map. In this way, the information on the impurity depth profiles at all different parts of the sample can be simultaneously processed. In this report, the physical principle of feature selection is demonstrated. The noise robustness of the method is also discussed.

To study the photo induced non-equilibrium state, it is highly desired to probe the dynamics with atomic scale and ultrafast time resolution. In this study, we have developed time-resolved THz-STM, which uses monocycle THz pulse as transient bias voltage between the tunnel junction in STM. By using time-resolved THz-STM, we have succeeded in measuring photo induced carrier dynamics of 2H-MoTe₂ with ps time resolution.

Like inorganic semiconductor electronic devices, the functionality of organic devices are dominated by the interface. While the transport properties of organic materials depend on relative position/angle of neighboring molecules, experimental examination of surface relaxation of organic semiconductors has been sparse. We have studied surface structure relaxation of various organic semiconductor crystals, and found that the effect of the surface on organic semiconductors is limited to one molecular layer. Recently performed structure analysis of paint-made crystalline monolayer and double layer will be also presented.

Methane conversion reactions on Pd single crystals were investigated by soft X-ray near-ambient pressure photoelectron spectroscopy. AP-XPS and mass spectroscopy measurements were performed simultaneously during linear heating and cooling processes of the Pd samples in the presence of oxygen and methane gases to reveal surface oxidation states and reactivity. The reactivity depends significantly on the oxidation state of the surface. This indicates that gas pressure and composition are key parameters affecting the reactivity.

I this talk, I would like to discuss applications of X-ray Spectro-Ptychography, the combination of Ptychography imaging and XAFS spectroscopy through the 3-dimensional Chemical state visualization of metal-supported Ceria-Zirconia catalyst single particles. Additionally, the groupings of lattice oxygen diffusion in the catalyst particles were investigated by non-supervised learning analysis of 3-dimensional chemical state visualization information.

X-ray photoelectron spectroscopy (XPS) is capable of analyzing elemental compositions and oxidation states of surfaces and interfaces in a non-destructive manner. Although it intrinsically requires vacuum, it has been utilized for analyzing solid-liquid interfaces in combination with various materials and technologies. Recently, we developed an environmental cell in which a liquid portion is enclosed in vacuum by utilizing an ultrathin silicon based membrane as a separator between liquid and vacuum. When x-rays were incident on the membrane, photoelectrons ejected from the liquid phase and at the membrane-liquid interfaces were successfully collected through the membrane by a hemispherical photoelectron analyzer placed in vacuum. In the present talk, a few demonstrations of in situ XPS utilizing synchrotron light sources and in-house apparatus equipped with a conventional Al-Kα source.

Soft X-ray absorption spectroscopy (XAS) is an effective method to reveal local structures of liquids with different elements, but the measurement is difficult due to the strong absorption of soft X-rays by air and liquid. In this talk, we discuss molecular interactions of solutes with solvent water in solution from the chemical shift analyses in XAS of several liquid samples, which were measured by using our transmission-type liquid flow cell. We also report the application of XAS of liquids to chemical reaction in solution such as an electrode solid-liquid interface during electrochemical reaction and a laminar flow in microfluidics.

Scanning tunneling potentiometry (STP) provides nano-scale spatial distribution of surface electrical potential in mV resolution. However, STP has seldom been applied to atomically-ordered surfaces under ultrahigh vacuum (UHV). We have developed UHV-STP, succeeded in STP on the Si(111)-(7x7) surface, and observed potential drop at the phase boundaries, which has not been reported before.

On-surface synthesis in ultra-high vacuum (UHV) has been interested since we can adsorb guest metal atoms at any desired positions in single organic molecules, which cannot be performed using conventional liquid synthesis. In this study, Fe atoms were successfully deposited on a CuPc single molecule adsorbed on Cu(111). All experiments were performed using home-built UHV scanning tunneling microscopy (STM) at 5 K. Fe single atoms on Cu(111) did not show Kondo resonance. However, an Fe single atom adsorbed at CuPc side group showed Kondo resonance (Kondo temperature ~56 K). The largest resonance was observed at the edge of the side group instead of the center position of the Fe atom.

New novel quantum spin states could be generated with a control of magnetic frustration array including non-collinear magnetic coupling between atoms. We focus on ring molecules, which are able to capture guest atoms. We succeeded to grow a ring molecular array using tetrabromide dibenzo 18-crown-6 ether on Cu(111). Magnetic atoms were deposited on this molecular array. We will report magnetic coupling, electronic states, and adsorption structures by means of ultra-high vacuum low-temperature scanning tunneling microscopy (STM).

Details of relationship between magnetization tilt angle and thickness in Co/W(110) had been unclear so far. In the present study, we deposited Co with various coverages less than 10 ML on W(110) and analyzed the magnetization tilt angle as well as the thickness at each position in the field of view with spin-polarized LEEM. It was found from the result that there were regions with the same thickness but different magnetization tilt angles and details of non-monotonic change of the magnetization tilt angle with the thickness were revealed.