Massive ground ice found in the Barrow Permafrost Tunnel at 3–7 m depths from the surface has been interpreted as an ice wedge and used to reconstruct early Holocene environmental changes. To better understand the development of this ground ice, we conducted radiocarbon dating for 34 samples of plant remains from the massive ground ice and underlying sediment layer. A significantly large gap in the measured radiocarbon ages (more than 24 ka) between massive ice and the underlying sediment layer throughout the tunnel profile suggested at least two possibilities. One is that the lower and older sediment layer had thrust upwards at the boundary between intruding ice wedge and adjacent sediment, and the growing ice had pushed the sediment sideways. Another is that erosional events had removed surface materials at about 12–36 ka BP (14–41 cal ka BP) before the overlaying sediment layer with massive ground ice developed. The overall distribution of radiocarbon ages from the massive ice supported the ice-wedge hypothesis as a formation mechanism, although our results showed several age inversions and large fluctuations. Dating of densely spaced samples revealed two ground-ice regions with similar ages around 11–11.5 and 10–10.5 ka BP divided by a relatively narrow region of transitional ages along the tunnel long-axis. This distribution may be explained by a possible misalignment between the sampling direction and the ice-wedge growth line or by intermittent ice growth with repeated cracking at more random locations than the classic ice-wedge growth model suggested.

Thermosetting resins are one of the most widely used functional materials in industrial applications. Although some of the physical properties of thermosetting resins are controlled by changing the functional groups of the raw materials or adjusting their mixing ratios, it was conventionally challenging to construct machine learning (ML) models, which include both mixing ratio and chemical information such as functional groups. To overcome this problem, we propose a machine learning approach based on extended circular fingerprint (ECFP) in this study. First, we predicted the classification of raw materials by the random forest, where ECFP was used as the explanatory variable. Then, we aggregated ECFP for each classification predicted by the random forest. After that, we constructed the prediction model by using the aggregated ECFP, feature quantities of reaction intermediates, and curing conditions of resin as explanatory variables. As a result, the model was able to predict in high accuracy (R^2 = 0.8), for example, the elastic modulus of thermosetting resins. Furthermore, we also show the result of verification of prediction accuracy in first step, such as using the one-hot-encording. Therefore, we confirmed that the properties of thermosetting resins could be predicted using mixed raw materials by the proposed method.

Design processes of functional polymers were accelerated by adopting the Bayesian optimization; the number of trials in the process was substantially reduced. The optimization process was more than forty time accelerated to find out the target polymer compared to the random selection. The optimization efficiency was found to be successfully improved by utilizing the standard deviation of predicted probability distribution of objective function. The performance of the method was robust for dataset size in the analysis; the target polymer could be found even for a small training dataset. The proposed method is a promising tool for the high-performance polymer design, and a wide range of its applications will be expected in the polymer industry.

Ca-Mg-Si films were firstly prepared on (001)Al2O3 substrates by RF-magnetron sputtering method from Mg disc target together with Ca and Si chips. The composition of the deposited films was controlled by adjusting deposition temperature and Ca/Si area ratio of Ca and Si chips on Mg disk target. Ca0.32Mg0.33Si0.35 film deposited at 610 K consisted of a single phase of CaMgSi and this CaMgSi phase was stable after heat treated at 770 K under an atmospheric Ar with 5% -H2. As-deposited film shows the semiconductor behavior and have a power factor of 50 μW/(mK2) at 670 K, while annealed one showed the metallic behavior and its power factor down below 10 μW/(mK2) at 320-770 K. On the other hand, Ca0.27Mg0. 51Si0.2 film deposited at 590 K showed no obvious crystalline phase but became single phase of Ca7Mg7.25Si14 after heat treatment at 770 K under an atmospheric Ar with 5% -H2. As deposited film had a large power factor of 100 μW/(mK2) at 670 K. However, power factor decreased below 1 μW/(mK2) at 320-770K after the heat treatment at 770 K under an atmospheric Ar with 5% -H2.

A method for controlling the conduction-type in Mg2Si films without doping is investigated. Mg2Si films exhibit p-type conduction after a post-heat treatment up to 500 °C in atmospheric He. However, covering the films with Mg ribbon during a subsequent heat treatment at 500 °C converts the conduction to n-type, demonstrating that the heat treatment atmosphere can control the conduction type. Based on the reported first principles calculations suggesting that interstitial Mg and Mg vacancies in Mg2Si are the origins of n-type and p-type conduction, respectively, the post-heat treatment in He induces Mg vacancies due to the evaporation of Mg from the film, resulting in p-type conduction. The subsequent heat treatment when the film is covered with Mg ribbon fills the Mg vacancies and the additional interstitial Mg is incorporated, resulting in n-type conduction. These observations differ from the reported data for heat treatment of stable n-type conduction in non-doped Mg2Si-sintered bodies and may realize a novel control method for the conduction type in Mg2Si films.

Using micro-Raman spectroscopy, we identified the chemical forms of methanesulfonate salt particles in reference samples of the Dome Fuji (Antarctica) ice core. We found only (CH3SO3)2Mg nH2O among methanesulfonate salts, and this salt particle is most prevalent in the Last Glacial Maximum (LGM) ice. We suggest that during the LGM, (CH3SO3)2Mg nH2O may have formed in the atmosphere through the chemical reaction of CH3SO3H with sea salts, but probably not in the firn and ice due to the neutralization of acid in LGM ice of inland Antarctica.

This study clarifies changes in the chemical forms of microparticles during Termination I, the period of drastic climate change between the Last Glacial Maximum (LGM) and the Holocene. We determine the chemical forms of individual water-soluble microparticles through micro-Raman spectroscopy and compare the relative frequencies of different types with the ion concentrations in melted ice. Micro-Raman spectroscopy shows that Na2SO4·10H2O and MgSO4·11H2O are abundant in Holocene ice, while CaSO4·2H2O and other salts are abundant in LGM ice. Further, the number of CaSO4·2H2O particles is strongly correlated with the concentration of Ca2+ during Termination I. Taken together, the evidence strongly suggests that most of the Ca2+ exists as CaSO4·2H2O. The different compositions of microparticles from the Holocene and LGM can be explained by ion balance arguments.

Stock options are used only sparingly in Japan. Japanese firms are more likely to adopt new stock option plans when they are more (less) owned by arms-length investors (stable and controlling shareholders). Those firms have significantly more independent boards and pay higher dividends surrounding the adoption year than their industry peers. These results suggest that firms adopting stock options endeavor to meet demands for good governance practice from arms-length shareholders and to follow good governance practices in other dimensions. The coexistence of arms-length, stable, and controlling shareholders generates a situation in which stock options are not widely used in Japan.

(KxNa1−x)NbO3 films were deposited on Nb-doped (100)SrTiO3 substrates at 240 °C for times between 1 and 6 h by a hydrothermal method. Over this time series, the measured (K + Na)/Nb ratio of the films was found to remain constant, but the bulk K/(K + Na) ratio, x, decreased from an initial value of 0.75–0.56. It was determined that film growth initially proceeded through crystallization of the K-rich phase (K0.75Na0.25)NbO3. For film growth times greater than 3 h, a second perovskite phase with a smaller unit cell volume was detected, with an estimated composition of (K0.36Na0.64)NbO3. As such, the measured bulk composition value x = 0.56 was determined to be the result of a combination of these two phases, as opposed to originating from a single phase. Cross-sectional transmission electron microscopy analyses of films prepared for 6 h revealed that they consist of two layers in the direction normal to the substrate; this bilayer-type structure, only observed for hydrothermal growth of this material, is considered to arise from the large solubility mismatch between the Nb precursor and KOH and NaOH in the growth solution.

We propose some chemical processing procedures for fabricating thin films in Hf-Zr-O system by a unique film deposition technique using supercritical carbon dioxide fluid (scCO2), i.e., supercritical fluid deposition (SCFD), which would be an prospective approach for fabricating metal-oxide films for integrated circuits because of its unique characteristics; e.g., extraction ability, transportation capability, and reaction equilibrium etc., are quite favorable for the film deposition from metal-complex precursors.

The SCFD was accomplished in a closed batch-type reaction apparatus, consisting of two steps; (a) material deposition and (b) subsequent post-treatment under scCO2 atmosphere. Thin films of amorphous Hf-Zr-O were deposited on platinized silicon [(111)Pt/TiO2/(100)Si] substrates by SCFD using metal-complex precursors M[OCH(CH3)]2(C9H11O2)2 (M = Hf or Zr) at reaction temperature of 100 – 300 °C, significantly lower than those for MOCVD. These films possessed dielectric permittivity’s of approximately 20 – 25, comparable to those from conventional processes, although they still included residue of organic species that prompt the dielectric degradation under lower-frequency bias application.

One-axis oriented bismuth layer-structured dielectric (BLSD) films were designed using perovskite buffer layers for assembling the crystal orientation and the dielectric properties of the BLSD crystals on silicon wafer. The BLSD crystals with the general formula of (Bi2O2)2+-(Am-1BmO3m+1)2- possess excellent dielectric permittivity with lower size effect and temperature coefficient of capacitance (TCC), as well as high electrical resistivity along to the c-axis direction. These phenomena would contribute for constructing high performance dielectric devices driven under harsh environment, e.g., at high-temperature condition above 100°C. In this study, thin films of CaBi4Ti4O15 and SrBi4Ti4O15, kinds of BLSD compounds with the number of BO6 octahedra in pseudo-perovskite blocks, m, = 4, were prepared by chemical solution deposition (CSD) technique on (100)LaNiO3/(111)Pt/TiO2/(100)Si and (100)SrRuO3// (100)LaNiO3/(111)Pt/TiO2/(100)Si substrates. These films consisted of crystalline phase of BLSD crystal with preferential crystal orientation of (001) plane normal to the substrate surface. Anisotropic crystal growth of BLSD occurred by the lattice matching between pseudo-perovskite blocks in BLSD crystal and (100)LaNiO3 or (100)SrRuO3 plane with perovskite structure. The dielectric constants (εr) of (001)-plane oriented CaBi4Ti4O15 and SrBi4Ti4O15 films were approximately 250-350 at room temperature. The r values of the CaBi4Ti4O15 and SrBi4Ti4O15 films increased slightly with ambient temperature. The TCCs at a temperature range from 25 to 200°C were approximately +103 - +514 ppm/K respectively, which were significantly different from those of (Ba,Sr)TiO3 thin films and would satisfy the performance requirement for driving at high-temperature condition.

The artificial nano-clay powder was newly examined as a gelator of electrolyte of quasi-solid-state dye-sensitized solar cell (DSSC). The size of clay has two main distributions with 1.4 nm and 20 nm in diameter which are confirmed by STEM observation. The gelation point was determined by using Rheometer. The gel state maintained with more than 5wt% nano-clay in the acetonitrile based solvent. The quasi-solid-state DSSC with nano-clay electrolyte (10 wt%) was successfully showed a high photoelectric conversion efficiency of 10.3%, which is equivalent to that using a liquid electrolyte.

Tin-dioxide (SnO2) ultra-small nanorods (UNR) have been successfully synthesized using the novel micellar technique. From transmission electron microscopy, the average diameter and length of the UNRs are estimated to be 1.3 nm and 5.0 nm, respectively. The crystal structure of the SnO2 UNRs was found to be tetragonal from the glazing incidence x-ray diffraction. The optical band gap estimated from the absorption spectrum is blue-shifted by 1 eV from that of bulk (3.64 eV). The photoluminescence spectrum shows two groups of peaks each with several fine peaks, one in the wavelength range of 270 – 370 nm and the other in the range of 380 – 500 nm which are due to the strong quantum confinement effect.

We demonstrate a novel technique using supercritical carbon dioxide (scCO2) fluid for lowering processing temperature of sol-gel-derived metal oxide thin films. The film processing was performed in a hot-wall closed vessel filled with scCO2 fluid. The effects of fluid temperature and additives on the sol-gel synthesis reaction under scCO2 fluid were also investigated. Precursor films of titanium dioxide (TiO2) prepared on silicon wafer and silica glass by sol-gel coating using Ti-alkoxide were converted to crystalline TiO2 (anatase) films successfully by treatment in scCO2 without additive agent at a fluid pressure of 15 MPa and at a substrate temperature of above 250°C, which is significantly lower than the processing temperature of conventional sol-gel deposition. Furthermore, additive agents such as water (H2O) and nitrogen-oxygen mixture (N2-O2) promoted the decomposition and crystallization of precursor films in scCO2 fluid to form the crystalline TiO2 (anatase) films at a substrate temperature at as low as 200°C although it also produced surface absorbates consisted of hydroxides on the film surface. The experimental results suggested that the hydrolysis and polymerization reactions of Ti-alkoxide in the precursor films were proceeded by the scCO2 processing to form titanium-oxygen (Ti-O) networks and that byproducts such as alcohols were removed from the resulting films.