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Background Contour delineation, a crucial process in radiation oncology, is time-consuming and inaccurate due to inter-observer variation has been a critical issue in this process. An atlas-based automatic segmentation was developed to improve the delineation efficiency and reduce inter-observer variation. Additionally, automated segmentation using artificial intelligence (AI) has recently become available. In this study, auto-segmentations by atlas- and AI-based models for Organs at Risk (OAR) in patients with prostate and head and neck cancer were performed and delineation accuracies were evaluated. Methods Twenty-one patients with prostate cancer and 30 patients with head and neck cancer were evaluated. MIM Maestro was used to apply the atlas-based segmentation. MIM Contour ProtégéAI was used to apply the AI-based segmentation. Three similarity indices, the Dice similarity coefficient (DSC), Hausdorff distance (HD), and mean distance to agreement (MDA), were evaluated and compared with manual delineations. In addition, radiation oncologists visually evaluated the delineation accuracies. Results Among patients with prostate cancer, the AI-based model demonstrated higher accuracy than the atlas-based on DSC, HD, and MDA for the bladder and rectum. Upon visual evaluation, some errors were observed in the atlas-based delineations when the boundary between the small bowel or the seminal vesicle and the bladder was unclear. For patients with head and neck cancer, no significant differences were observed between the two models for almost all OARs, except small delineations such as the optic chiasm and optic nerve. The DSC tended to be lower when the HD and the MDA were smaller in small volume delineations. Conclusions In terms of efficiency, the processing time for head and neck cancers was much shorter than manual delineation. While quantitative evaluation with AI-based segmentation was significantly more accurate than atlas-based for prostate cancer, there was no significant difference for head and neck cancer. According to the results of visual evaluation, less necessity of manual correction in AI-based segmentation indicates that the segmentation efficiency of AI-based model is higher than that of atlas-based model. The effectiveness of the AI-based model can be expected to improve the segmentation efficiency and to significantly shorten the delineation time.

We fabricated unique ceramics matrix composites (CMCs) called natto-structured oxides using metal-ethylenediaminetetraacetic acid (EDTA) solution. The natto-structured oxide in this study is a combination of micron-sized oxide particles and oxide with nanoscale fibrous microstructures. The natto-structures were fabricated on Si substrates by spin-coating Er-EDTA solutions with hollow (Y2O3:Eu3+, SiO2) particles followed by atmospheric sintering. We investigated the effects of filler concentrations, rotation speeds, and filler diameters on the formation of natto-structured oxides. The results indicate that the rotating centrifugal force in the spin coating process is the dominant factor affecting the formation of natto-structured oxides.

Nanoporous carbon (NPC) with high hydrogen storage capacity was fabricated from rice husk. The rice husk was activated using KOH, and the cooling step during the KOH activation process was varied. The specific surface areas, pore size distributions, and hydrogen storage capacities of the fabricated NPC samples were determined. We found that while the specific surface area did not change with the choice of the cooling process, the pore size distribution did. Furthermore, in the case of rapid cooling, the maximum hydrogen storage capacity at 77 K was 7.2 wt%, while that for natural cooling was 5.5 wt%. Thus, it can be concluded that the cooling procedure used during the KOH activation process determines the hydrogen storage properties of the thus-fabricated NPC materials.

The morphology and microstructure of splats impact the comprehensive capability of a new coating methodology called chelate flame spraying (CFS). This study addresses the quantitative characterization of the spread morphologies of flame sprayed Er2O3 splats directly deposited under different spray conditions on aluminum alloy substrates with a mirror finish. The influence of the in-flight particle temperature and velocity, carrier gas type, and carrier gas ratio on the solidification mechanism of molten droplets was investigated. Image analysis methods were employed to identify single splats from the morphology observed with field-emission scanning electron microscopy (FE-SEM). In addition, Er2O3 films were synthesized on an Al–Mg alloy (A5052) substrate using N2 or O2 as the carrier gas. When O2 was used as the carrier gas, 109-μm-thick films were deposited on the A5052 substrate. The cross-sectional porosity of the films was 3.8%. In contrast, films with 101-μm thickness were synthesized on the A5052 substrate when N2 was used as the carrier gas. The cross-sectional porosity of these films was 13.8%. The results showed that the carrier gas type (N2) and carrier gas ratio had a significant effect on the flattening behavior of the molten droplets. A spraying method combined with multidimensional modes is proposed to control the morphology of the splats.

In this study, we propose a method for sealing porous samples using aqueous solutions of metal-ethylenediaminetetraacetic acid (EDTA) complexes. Gd-doped ceria (GDC) films were synthesized on porous NiO-mixed yttria-stabilized zirconia (YSZ) samples by coating them with a (Ce, Gd)-EDTA complex solution and subsequently sintering them in air at 850 °C for 1 h. When the Ce/Gd ratio in EDTA was 0.8:0.2, only a crystalline Ce0.8Gd0.2O1.9 phase was formed on the surface. The obtained results confirmed that the proposed treatment is effective for sealing the surfaces and open pores of porous samples. Finally, it was observed that a GDC layer was formed both at the sample surface and within the pores smaller than 1.7 μm.

Dual-ion batteries (DIBs) are one of the promising candidates to meet the low-cost requirements of commercial applications because of their high working voltage, excellent safety, and environmental...

Purpose Ionization chambers are widely used for dosimetry with megavoltage photon beams. Several properties of ionization chambers, including the cable effect, polarity effect, and ion recombination loss, are described in standard dosimetry protocols. The cable effect is categorized as the leakage current and Compton current, and careful consideration of these factors has been described not only in reference dosimetry but also in large fields. However, the mechanism of Compton current in the cable has not been investigated thoroughly. The cable effect of ionization chambers in 6 MV X-ray beam was evaluated by measurement, and the mechanism of Compton current was investigated by Monte Carlo simulation. Materials and methods Four PTW ionization chambers (TM30013, TM31010, TM31014, and TM31016) with the same type of mounted cable, but different ionization volumes, were used to measure output factor (OPF) and cable effect measurement. The OPF was measured to observe any variation resulting from the cable effect. The cable effect was evaluated separately for the leakage current and Compton current, and its charge per absorbed dose to water per cable length was estimated by a newly proposed method. The behavior of electrons and positrons in the core wire was analyzed and the Compton current for the photon beam was estimated by Monte Carlo simulation. Results In OPF measurement, the difference in the electrometer readings by polarity became obvious for the mini- or microchamber and its difference tended to be larger for a chamber with a smaller ionization volume. For the cable effect measurement, it was determined that the contribution of the leakage current to the cable effect was ignorable, while the Compton current was dominant. The charge due to the Compton current per absorbed dose to water per cable length was estimated to be 0.36 ± 0.03 pC Gy-1 cm-1 for PTW ionization chambers. As a result, the contribution of the Compton current to the electrometer readings was estimated to be 0.002% cm-1 for the Farmer-type, 0.011% cm-1 for the scanning, and 0.088% cm-1 for microchambers, respectively. By the simulation, it was determined that the Compton current for MV x-ray could be explained by not only recoil electrons due to Compton scattering but also positron due to pair production. The Compton current estimated by the difference in outflowing and inflowing charge was 0.45 pC Gy-1 cm-1 and was comparable with the measured value. Conclusion The cable effect, which includes the leakage current and Compton current, was quantitatively estimated for several chambers from measurements, and the mechanism of Compton current was investigated by Monte Carlo simulation. It was determined that the Compton current is a dominant component of the cable effect and its charge is consistently positive and nearly the same, irrespective of the ionization chamber volume. The contribution of Compton current to the electrometer readings was estimated for chambers. The mechanism of Compton current was analyzed and it was confirmed that the Compton current can be estimated from the difference in outflowing and inflowing charge to and from the core wire.

Deep inspiration breath hold (DIBH) is a common method used worldwide for reducing the radiation dose to the heart. However, few studies have reported on the relationship between dose reduction and patient-specific parameters. The aim of this study was to compare the reductions of heart dose and volume using DIBH with the dose/volume of free breathing (FB) for patients with left-sided breast cancer and to analyse patient-specific dose reduction parameters. A total of 85 Asian patients who underwent whole-breast radiotherapy after breast-conserving surgery were recruited. Treatment plans for FB and DIBH were retrospectively generated by using an automated breast planning tool with a two-field tangential intensity-modulated radiation therapy technique. The prescribed dose was 50 Gy in 25 fractions. The dosimetric parameters (e.g., mean dose and maximum dose) in heart and lung were extracted from the dose–volume histogram. The relationships between dose–volume data and patient-specific parameters, such as age, body mass index (BMI), and inspiratory volume, were analyzed. The mean heart doses for the FB and DIBH plans were 1.56 Gy and 0.75 Gy, respectively, a relative reduction of 47%. There were significant differences in all heart dosimetric parameters (p

Ceramic architectures based on chemical vapor deposition (CVD) are used to create unique crystal structures, morphologies, and properties. This study proposed room-temperature THz gas sensing using terahertz time-domain spectroscopy (THz-TDS) with ceramic architectures. We synthesized ceramic films on porous glass. Zinc oxide films were created using atmospheric CVD and amorphous carbon nitride films using the dissociative excitation reaction of BrCN with metastable Ar atoms. The transmission method was used in THz-TDS. A stainless hand-made gas cell with a Si window was applied for THz gas sensing. We defined "phase delay" equals VOC sensing response amount of sensing materials at each duration. Ppm-order THz gas sensing was performed.

Purpose To increase the superficial dose and reduce the brain dose for radiotherapy of scalp angiosarcoma, we propose a novel irradiation technique of tangential irradiation volumetric modulated arc therapy (TI-VMAT). Methods TI-VMAT and the conventional VMAT treatment plans for thirteen scalp angiosarcoma patients were created with a prescribed dose of 70 Gy. Each treatment was normalized to cover 95% of the planning target volume (PTV) with its prescribed dose. To realize TI-VMAT, an avoidance structure (AS) function was applied. AS was defined as a contour subtracted PTV by a certain space from the brain contour. TI-VMAT treatment plans for six different spaces between PTV and AS were developed and compared with the conventional VMAT treatment plan with respect to the following dosimetric parameters: homogeneity index (HI) and conformity index (CI) of the PTV, mean brain dose, and brain volume irradiated with 20% (V20% [cc]), 40% (V40% [cc]), 60% (V60% [cc]), 80% (V80% [cc]), and 100% (V100% [cc]) of the prescribed dose. Results HI and CI were comparable between TI-VMAT and the conventional VMAT, the mean brain dose for TI-VMAT with AS defined by a space of 2.0 cm and jaw tracking was 14.27 Gy, which was significantly lower than that for the conventional VMAT (21.20 Gy). In addition, dosimetric parameters such as V20% [cc] were significantly suppressed compared to those for high doses. Conclusion Our proposed irradiation technique TI-VMAT shows the potential to reduce radiation doses in the brain with maintaining higher dose coverage on the PTV.

PURPOSE The ICRU has published new recommendations for ionizing radiation dosimetry. In this work, the effect of recommendations on the water-to-air and graphite-to-air restricted mass electronic stopping power ratios (sw, air and sg, air ) and the individual perturbation correction factors Pi was calculated. The effect on the beam quality conversion factors kQ for reference dosimetry of high-energy photon beams was estimated for all ionization chambers listed in the Addendum to AAPM's TG-51 protocol. METHODS The sw, air , sg, air , individual Pi, and kQ were calculated using EGSnrc Monte Carlo code system and key data of both ICRU report 37 and ICRU report 90. First, the Pi and kQ were calculated using precise models of eight ionization chambers: NE2571 (Nuclear Enterprise), 30013, 31010, 31021 (PTW), Exradin A12, A12S, A1SL (Standard imaging), and FC-65P (IBA). In this simulation, the radiation sources were one 60 Co beam and ten photon beams with nominal energy between 4 MV and 25 MV. Then, the change in kQ for ionization chambers listed in the Addendum to AAPM's TG-51 protocol was calculated by changing the specification of the simple-model of ionization chamber. The simple-models were made with only cylindrical component modules. In this simulation, the radiation sources of 60 Co beam and 24 MV photon beam were used. RESULTS The significant changes (p

Respiratory‐gated volumetric modulated arc therapy (gated VMAT) involves further complexities to the dose delivery process because the gantry rotation must repeatedly stop and restart according to the gating signals. In previous studies, the gantry rotation performances were evaluated by the difference between the plan and the machine log. However, several reports pointed out that log analysis does not sufficiently replicate the machine performance. In this report, a measurement‐based quality assurance of the relation between the gantry angle and gate‐on or gate‐off using triggered kilovoltage imaging and a cylinder phantom with 16 ball bearings is proposed. For the analysis, an in‐house program that estimates and corrects the phantom offset was developed. The gantry angle in static and gated arc delivery was compared between the machine log and the proposed method. The gantry was set every 5 deg through its full motion range in static delivery, and rotated at three speeds (2, 4 and 6 deg s‐1) with different gating intervals (1.5 or 3.0 s) in gated arc delivery. The mean and standard deviation of the angular differences between the log and the proposed method was −0.05 deg ± 0.12 deg in static delivery. The mean of the angular difference was within ±0.10 deg and the largest difference was 0.41 deg in gated arc delivery. The log records the output of the encoder so that miscalibration and mechanical sagging will be disregarded. However, the proposed method will help the users to detect the mechanical issues due to the repeated gantry stops and restarts in gated VMAT.

Currently, hollow sphere insulating materials are of importance for applications such as energy storage and savings and cryogenic engineering. The structures are formed by single hollow spheres, which can be joined, for example, by sintering. In this study, a 15 wt% Er-EDTA complex aqueous solution in which hollow Y2O3 spheres were mixed was used as the deposition body, and pencil spraying and sintering (PSS) was used to synthesize an Er2O3 hollow Y2O3 sphere composite film on a polished Si substrate. The structure of the composite film was successfully controlled by adjusting the 15 wt% Er-EDTA solution/hollow Y2O3 sphere mass ratio and the jet-to-substrate distance in the PSS process. In addition, the thermal insulation capability of the films was evaluated by the thermal steady-state method. The results show that the Er2O3/hollow Y2O3:Eu sphere composite films have a higher thermal insulation capability at a jet-to-substrate distance of 150 mm and a mass ratio (g) of 3.5:1. For the composite films with thicknesses of 38–92 µm, cross-sectional hollow ratio of 0.8–8.7% and void ratio of 6.3–13.1%, the temperature drop due to the porous (including hollow spheres and voids) structure films at 440°C is ΔTf =47°C. This is mainly associated with the film having more complicated microstructures. Therefore, the Er2O3/Y2O3:Eu composite film has good thermal insulation performance, and a simple preparation method for many kinds of hollow sphere films with complex structures and high porosities by using complex solutions with different compositions is provided.

A realistic X‐ray energy spectrum is essential for accurate dose calculation using the Monte Carlo (MC) algorithm. An energy spectrum for dose calculation in the radiation treatment planning system is modeled using the MC algorithm and adjusted to obtain acceptable agreement with the measured percent depth dose (PDD) and off‐axis ratio. The simulated energy spectrum may not consistently reproduce a realistic energy spectrum. Therefore, direct measurement of the X‐ray energy spectrum from a linac is necessary to obtain a realistic spectrum. Previous studies have measured low photon fluence directly, but the measurement was performed with a nonclinical linac with a thick target and a long target‐to‐detector distance. In this study, an X‐ray energy spectrum from a clinical linac was directly measured using a NaI(Tl) scintillator at an ultralow dose rate achieved by adjusting the gun grid voltage. The measured energy spectrum was unfolded by the Gold algorithm and compared with a simulated spectrum using statistical tests. Furthermore, the PDD was calculated using an unfolded energy spectrum and a simulated energy spectrum was compared with the measured PDD to evaluate the validity of the unfolded energy spectrum. Consequently, there was no significant difference between the unfolded and simulated energy spectra by nonparametric, Wilcoxon's rank‐sum, chi‐square, and two‐sample Kolmogorov–Smirnov tests with a significance level of 0.05. However, the PDD calculated from the unfolded energy spectrum better agreed with the measured compared to the calculated PDD results from the simulated energy spectrum. The adjustment of the incident electron parameters using MC simulation is sensitive and takes time. Therefore, it is desirable to obtain the energy spectrum by direct measurement. Thus, a method to obtain the realistic energy spectrum by direct measurement was proposed in this study.

We investigated the refractive index (n) and extinction coefficient (k) of diamond-like carbon (DLC) films formed by gas cluster ion beam (GCIB)-assisted deposition. DLC films are classified into four types based on n and k values (at λ = 2.25 eV). We formed the nonclassified DLC film which has high n (2.4–3.0) and k (0.75–1.0) values. The Raman peak intensity ratio (I D/I G) of this film was 0.601, which corresponds to the value of a-C:H or ta-C:H. The film density was 2.71 g cm−3. The nonclassified DLC film has intermediate properties between a-C:H and ta-C:H with respect to the density and k.

In this study, the optimum density scaling factors of phantom materials for a commercially available three‐dimensional (3D) dose verification system (Delta4) were investigated in order to improve the accuracy of the calculated dose distributions in the phantom materials. At field sizes of 10 × 10 and 5 × 5 cm2 with the same geometry, tissue‐phantom ratios (TPRs) in water, polymethyl methacrylate (PMMA), and Plastic Water Diagnostic Therapy (PWDT) were measured, and TPRs in various density scaling factors of water were calculated by Monte Carlo simulation, Adaptive Convolve (AdC, Pinnacle3), Collapsed Cone Convolution (CCC, RayStation), and AcurosXB (AXB, Eclipse). Effective linear attenuation coefficients (μ eff) were obtained from the TPRs. The ratios of μ eff in phantom and water ((μ eff)pl,water) were compared between the measurements and calculations. For each phantom material, the density scaling factor proposed in this study (DSF) was set to be the value providing a match between the calculated and measured (μ eff)pl,water. The optimum density scaling factor was verified through the comparison of the dose distributions measured by Delta4 and calculated with three different density scaling factors: the nominal physical density (PD), nominal relative electron density (ED), and DSF. Three plans were used for the verifications: a static field of 10 × 10 cm2 and two intensity modulated radiation therapy (IMRT) treatment plans. DSF were determined to be 1.13 for PMMA and 0.98 for PWDT. DSF for PMMA showed good agreement for AdC and CCC with 6 MV x ray, and AdC for 10 MV x ray. DSF for PWDT showed good agreement regardless of the dose calculation algorithms and x‐ray energy. DSF can be considered one of the references for the density scaling factor of Delta4 phantom materials and may help improve the accuracy of the IMRT dose verification using Delta4.

Diamond-like carbon (DLC) films were deposited by pulsed filtered cathodic vacuum arc (FCVA) deposition. The microstructure, mechanical and optical properties of DLC films have been investigated as functions of the variation in the substrate negative direct current bias voltage (Vbias) from 0.0 to 1.5 kV. Raman and X-ray photoelectron spectroscopy results show a correlation between the ID/IG ratio and the microstructure in terms of the sp3/sp2 ratio to Vbias. This fact shows that a significant change in the sp3 content, which is attributed to the transformation from graphite-like to diamond-like, is accompanied by a decreasing ID/IG ratio. The relatively high mass density of the films in the range of 2.51 to 2.79 g/cm3 can be obtained with biasing. The mechanical properties, i.e., the hardness and elastic modulus, were 13–25 and 114–145 GPa, respectively. The improvement of the mechanical properties is due to the formation of the compressive residual stress and the local density depending on Vbias. The relationship between the refractive index and the ID/IG ratio agree well with the microstructure and mechanical properties of DLC films. All of these results indicate a vital role of Vbias in determining the DLC properties.

We report on the pore structure and hydrogen storage properties of nanoporous carbon (NPC) prepared by KOH activation of rice husk ash. The specific surface area of the NPC increased from 220 to 2770 m2/g with an increase in KOH/rice husk ash weight ratio from 1:1 to 7:1. In addition, the micropore volume of the NPC increased from 0.08 to 0.73 cm3/g with an increase in KOH quantity. Furthermore, the mesopore volume also increased from 0.08 to 2.17 cm3/g. Results of pore size distribution studies indicated NPC pore size widening from the micropore to the mesopore scale with the addition of further KOH. The stored hydrogen content of the NPC therefore increased with the development of the pore structure. From these results, we propose that this change in pore size is responsible for the increase in stored hydrogen content in NPCs.

Near-surface voids on a cement concrete sample were successfully sealed by applying a metal-ethylenediaminetetraacetic (EDTA) acid complex solution, followed by treatment with high-heat hydrogen/oxygen (H2-O2) coupled flame. The calcium aluminates used for sealing were fabricated on cement substrates using calcium-aluminate (Ca,Al)-EDTA solutions prepared at various elemental ratios. The sealing effects were investigated through crystal & pore structure analysis and water permeability tests, using X-ray computed tomography (X-CT). Existence of the calcium aluminates were confirmed. From X-CT analysis, the average void diameter was changed from 16 μm to 10 μm with the calcium aluminate’s sealing. A sealing process model combining metal-EDTA complex solutions and high-heat treatment, intended for the surface sealing of cement concretes used in construction, was comprehensively proposed.

Lithium (Li)-metal anodes are of great promise for next-generation batteries due to their high theoretical capacity and low redox potential. However, Li-dendrite growth during cycling imposes a tremendous safety concern on the practical application of Li-metal anodes. Herein, an effective approach to suppress Li-dendrite growth by coating a polypropylene (PP) separator with a thin layer of ultrastrong diamond-like carbon (DLC) is reported. Theoretical calculations indicate that the DLC coating layer undergoes in situ chemical lithiation once assembled with the lithium-metal anode, transforming the DLC/PP separator into an excellent 3D Li-ion conductor. This in situ lithiated DLC/PP separator can not only mechanically suppress Li-dendrite growth by its intrinsically high modulus (≈100 GPa), but also uniformly redistributes Li ions to render dendrite-free lithium deposition. The twofold effects of the DLC/PP separator result in stable cycling of lithium plating/stripping (over 4500 h) at a high current density of 3 mA cm-2 . Remarkably, this approach enables more than 1000 stable cycles at 5 C with a capacity retention of ≈71% in a Li || LiFePO4 coin cell and more than 200 stable cycles at 0.2 C in a Li || LiNi0.5 Co0.3 Mn0.2 O2 pouch cell with cathode mass loading of ≈9 mg cm-2 .

Purpose We evaluated the energy responses of a radiophotoluminescent glass dosimeter (RPLD) to variations in small-field and intensity-modulated radiation therapy (IMRT) conditions using experimental measurements and Monte Carlo simulation. Methods Several sizes of the jaw and multileaf collimator fields and various plan-class IMRT-beam measurements were performed using the RPLD and an ionization chamber. The field-size correction factor for the RPLD was determined for 6- and 10-MV X-rays. This correction factor, together with the perturbation factor, was also calculated using Monte Carlo simulation with the EGSnrc/egs_chamber user code. In addition, to evaluate the response of the RPLD to clinical-class-specific reference fields, the field-size correction factor for the clinical IMRT plan was measured. Results The calculated field-size correction factor ranged from 1.007 to 0.981 (for 6-MV X-rays) and from 1.012 to 0.990 (for 10-MV X-rays) as the jaw field size ranged from 1 × 1 cm2 to 20 × 20 cm2. The atomic composition perturbation factor for these jaw fields decreased by 3.2% and 1.9% for the 6- and 10-MV fields, respectively. The density perturbation factor was unity for field sizes ranging from 3 × 3 cm2 to 20 × 20 cm2, whereas that for field sizes ranging from 3 × 3 cm2 to 1 × 1 cm2 decreased by 3.2% (for 6-MV X-rays) and 4.3% (for 10-MV X-rays). The volume-averaging factor rapidly increased for field sizes below 1.6 × 1.6 cm2. The results for the MLC fields were similar to those for the jaw fields. For plan-class IMRT beams, the field-size correction and perturbation factors were almost unity. The difference between the doses measured using the RPLD and ionization chamber was within 1.2% for the clinical IMRT plan at the planning-target volume (PTV) region. Conclusions For small fields of size 1.6 × 1.6 cm2 or less, it was clarified that the volume averaging and density perturbation were the dominant effects responsible for the variation in the RPLD response. Moreover, perturbation correction is required when measuring a field size 1.0 × 1.0 cm2 or less. Under the IMRT conditions, the difference in the responses of the RPLD between the reference conditions and the PTV region calculated by Monte Carlo simulation did not exceed 0.8%. These results indicate that it is feasible to measure IMRT dosage using an RPLD at the PTV region. This article is protected by copyright. All rights reserved.

The irradiation effect on fluorinated diamond-like carbon (F-DLC) film was investigated by measuring the dose dependence of various film properties using synchrotron radiation (SR) in the soft X-rays in the SR dose region from 0 to 2000 mA h. Film flatness was maintained but various film properties and surface properties were found to be changed by the SR irradiation. Wettability of the F-DLC film surface increased dramatically within 20 mA h SR exposure, which was ascribed to the decrease in fluorine on the film surface. Film thickness, film density, composition ratio of fluorine atom in film decreased and sp 2 / ( sp 2 + sp 3 ) ratio of carbon atoms increased within 300 mA h SR exposure, which were ascribed to the desorption of species containing fluorine atoms. In addition, dominant desorbed species emitted from F-DLC film were found in the fluorocarbon group, CF x . Changes in film properties and film thickness did not proceed, when fluorine content in the F-DLC film decreased to about 10% after the 300 mA h SR exposure.

In this study, we synthesized dense metal oxide films from a metal-ethylenediaminetetraacetic acid complex using a flame sprayer. Erbium oxide (Er2O3), Yttrium oxide (Y2O3) films were synthesized on stainless steel substrates using N2, air (O2 + N2), or O2 as the carrier gas and a H2-O2 mixture as the combustion gas. When O2 was used as the carrier gas, 9.9–20.5 μm-thick oxide layers were deposited on the SUS substrate. The cross-sectional porosities of the films were 3–5%. In contrast, oxide layers with 8.1–15.8 μm thickness were synthesized on stainless steel substrates when N2 and air were used as the carrier gases. The cross-sectional porosities of these films were 16.1–23.4%. These results indicated that the carrier gas plays an important role in determining the thickness and porosity of the resulting film.

The classification of diamond-like carbon (DLC) films is imperative in guiding large-scale industrial productions. However, it is not easy to classify this issue based on the structural composition and obtained properties, especially, when the film contains a certain amount of hydrogen. In the present study, two types of hydrogenated DLC films were prepared by electron-cyclotron-resonance chemical-vapor-deposition method with pure C2H2 and Ar gasses with applied negative bias voltages of 0 and 0.5 kV. The structural and surface analyses of these films have shown significant changes of physical and mechanical properties with high reproducibility and low oxygen contents. The comparison of H/C atomic ratio extracted from the combination of Rutherford backscattering and elastic recoil detection analysis and the solid-state nuclear magnetic resonance (NMR) illustrated that the NMR analysis of the present work provides a significant contribution. Therefore, we compared quantitatively the sp3/(sp2 + sp3) ratios in the hydrogenated DLC films using the near-edge X-ray absorption fine-structure (NEXAFS) and solid-state NMR methods. The signals of hydrocarbon sp3 ( CH, CH2 and CH3) and a network of sp3 hybridized carbon (C-sp3) can be separated by the solid-state 13C NMR measurement, from which it is concluded that the former do not enable a detailed interpretation for the internal structural changes of the hydrogenated DLC films with the increase of applied bias voltage.

The amount of hydrogen released after high-pressure hydrogen loading in carbonate was evaluated. Calcium carbonate (CaCO3) and Mg-substituted CaCO3 were selected as adsorbents. Their crystal structures, specific surface areas (SBET), hydrogen content at high pressure, and the amount of hydrogen released in water were investigated. Calcitic CaCO3 and (Ca0.94,Mg0.06)CO3 structures were identified for the respective samples, and their adsorption forms were found to be of type II as per IUPAC classification. The SBET values were 2.9–6.8 m2/g. The hydrogen content in (Ca0.94,Mg0.06)CO3 was found to be higher than that of calcite CaCO3 at high pressures. Furthermore, the amount of hydrogen released by the (Ca0.94,Mg0.06)CO3 sample was ~20-times higher than that from calcitic CaCO3, measured by gas chromatography. Keywords: Carbonate, Hydrogen absorption/release, Loading hydrogen at high pressure, Gas chromatography (GC)

The nanoporous carbon (NPC) performance, used for drug delivery carriers, wastewater treatment, or hydrogen storage, is strongly determined by the pore morphology during the desorption. In this work, the structural characteristics of NPC fabricated from rice husk by KOH activation were studied. X-ray diffractometry (XRD) and small-angle X-ray scatter were then implemented to characterize the pore size and adsorbate model under a series of adsorption–desorption conditions, combined with the details of the multilayer pore morphology obtained from gas adsorption. To this aim, the water was selected as adsorbate, which could be investigated under desorption conditions. The results confirmed that NPC changed from an amorphous structure to a regularly arrayed monolayer structure by introducing adsorbates and returns to their origin after thoroughly drying. A detailed understanding of the behavior of adsorbent and adsorbate may facilitate its storage ability and application in selective sorption, separation, and storage processes.

The accurate estimation of true density is a fundamental problem for nanoporous carbon (NPC) materials because of helium adsorption. In this study, we developed a method for measuring the true density of NPC fabricated from rice husks based on a gas constant-volume expansion method. The proposed method considers helium adsorption on NPCs. The obtained results indicated that NPC fabricated from rice husk with a 2986 m2/g specific surface area has a true density of 2.095 g/cm3 as determined by the proposed method. In contrast, using the commercial helium-substituted method, the true density was measured as 2.437 g/cm3. The average standard deviation values using the proposed method were 0.015–0.027, whereas those using the commercial helium-substituted method were 0.024–0.138. These results indicated that accurate determination of the true density of NPCs was accomplished by the proposed method.

Diamond-like carbon (DLC) films have been extensively applied in industries owing to their excellent characteristics such as high hardness. In particular, there is a growing demand for their use as protective films for mechanical parts owing to their excellent wear resistance and low friction coefficient. DLC films have been deposited by various methods and many deviate from the DLC regions present in the ternary diagrams proposed for sp3 covalent carbon, sp2 covalent carbon, and hydrogen. Consequently, redefining the DLC region on ternary diagrams using DLC coatings for mechanical and electrical components is urgently required. Therefore, we investigate the sp3 ratio, hydrogen content, and other properties of 74 types of amorphous carbon films and present the classification of amorphous carbon films, including DLC. We measured the sp3 ratios and hydrogen content using near-edge X-ray absorption fine structure and Rutherford backscattering-elastic recoil detection analysis under unified conditions. Amorphous carbon films were widely found with nonuniform distribution. The number of carbon atoms in the sp3 covalent carbon without bonding with hydrogen and the logarithm of the hydrogen content were inversely proportional. Further, we elucidated the DLC regions on the ternary diagram, classified the amorphous carbon films, and summarized the characteristics and applications of each type of DLC.

In this study, yttrium oxide (Y2O3) films were synthesized from a metal-ethylenediaminetetraacetic (metal-EDTA) complex by employing a H2-O2 combustion flame. A rotation apparatus and various cooling agents (compressed air, liquid nitrogen, and atomized purified water) were used during the synthesis to control the thermal history during film deposition. An EDTA·Y·H complex was prepared and used as the staring material for the synthesis of Y2O3 films with a flame-spraying apparatus. Although thermally extreme environments were employed during the synthesis, all of the obtained Y2O3 films showed only a few cracks and minor peeling in their microstructures. For instance, the Y2O3 film synthesized using the rotation apparatus with water atomization units exhibited a porosity of 22.8%. The maximum film’s temperature after deposition was 453 °C owing to the high heat of evaporation of water. Cooling effects of substrate by various cooling units for solidification was dominated to heat of vaporization, not to unit’s temperatures.

Hydrogenated amorphous silicon carbide films were fabricated using the decomposition of Si(CH 3 ) 4 with the microwave discharge flow of Ar. The changes of the chemical structure and the mechanical hardness of films were investigated upon the application of the radio-frequency bias voltages (− V RF ) to the substrate. The analysis was based on a combination of Rutherford backscattering and elastic-recoil detection analysis, the X-ray photoelectron spectroscopy, the glow discharge optical emission spectroscopy, the nano-indentation measurements, and Fourier-transformed infrared spectroscopy. The fraction of the C–Si bonding state has a positive dependence on − V RF , whereas that of the C–C bonds in the sp 3 hybridized state is negligible. In addition, hydrogen terminations were removed effectively under the low − V RF conditions of 0–20 V. The films show the penetration of O atoms from the atmospheric origin into the bulk region. The mechanical hardness of the present films is the result of the balance among these factors.

A high temperature ratio (HTR) method has been proposed to correct the linear energy transfer (LET) dependence of thermoluminescent (TL) efficiency. To realize the use of the slab-type thermoluminescence detector (TLD) that based on the phosphor Li3B7O12:Cu for heavy charged particle beam, the HTR method has been considered. To improve the reproducibility of HTR, the slow heating rate method is introduced in this report and the coefficient variations of HTR decreased from 10%–20% to 8%. The relation between TL-efficiency, HTR, and LET for Li3B7O12:Cu was manifested and the TL-efficiency as a function of HTR was derived in an attempt to measure the absorbed dose without LET information. The feasibility of the HTR method in therapeutic carbon beams was evaluated by comparing the dose estimated by Li3B7O12:Cu and by an ionization chamber. The accuracy of dose estimation in carbon beams was improved by using the HTR method, but there is room for further improvement. The use of Li3B7O12:Cu in heavy cha...

Yttria (Y2O3) films were deposited on stainless steel substrates from ethylenediaminetetraacetic·yttrium·hydrogen (EDTA·Y·H) complexes by flame spraying. The gas mixtures of acetylene-oxygen (C2H2-O2) or hydrogen-oxygen (H2-O2) were used for the combustion flame and the effects of the combustion gas species on Y2O3 films were investigated. Experiments revealed that the particles propelled in the H2-O2 flame had lower temperature and higher velocity compared with the particles in the C2H2-O2 flame. The existence of Y2O3 crystalline phases and complete decomposition of the EDTA·Y·H were confirmed. The porosity of the film was 25% when the H2-O2 flame was used and 32% when the C2H2-O2 flame was used. In addition, the Y2O3 films showed excellent adherability in tape tests. The H2-O2 flame is thus considered suitable for fabricating dense Y2O3 films.