Search

This review paper provides the present status of amorphous oxide semiconductor technology along with knowledge obtained to date on their carrier transport, defects and impurities in relation to their stability issues.

As a response to a comment by Gavriljuk and Teus, we discuss the effects of hydrogen-charging-induced crack formation and plastic deformation on a high hydrogen flux along the grain boundaries in pure iron. Because no cracks were observed in the microstructure of the pure iron specimen used in our study, the effects of crack formation could be ruled out. In contrast, dislocation localization near grain boundaries was observed, possibly due to a hydrogen concentration gradient; therefore, the presence of dislocations may assist hydrogen segregation and cause the high hydrogen flux.

The long quest for a measurement of the Lamb shift in muonic hydrogen is over. Last year we measured the 2S 1/2F=1 –2P 3/2F=2 energy splitting (Pohl et al., Nature, 466, 213 (2010)) in μp with an experimental accuracy of 15 ppm, twice better than our proposed goal. Using current QED calculations of the fine, hyperfine, QED, and finite size contributions, we obtain a root-mean-square proton charge radius of rp = 0.841 84 (67) fm. This value is 10 times more precise, but 5 standard deviations smaller, than the 2006 CODATA value of rp. The origin of this discrepancy is not known. Our measurement, together with precise measurements of the 1S–2S transition in regular hydrogen and deuterium, gives improved values of the Rydberg constant, R∞ = 10 973 731.568 160 (16) m–1 and the rms charge radius of the deuteron rd = 2.128 09 (31) fm.

The method of two-photon approximation for multiphoton decay is applied to the decay of the 4d state in the hydrogen atom. In the process of four-photon decay the two-photon contribution that leads to radiation escape, from the interaction with matter, is considered. This may be helpful for a strict description of the recombination process in the hydrogen atom and, in principle, for the history of hydrogen recombination in the early universe.

This white paper recommends that ASTM International develop standards to address the potential impact of hydrides on the long term performance of irradiated zirconium alloys. The need for such standards was apparent during the 2nd ASTM International Workshop on Hydrides in Zirconium Alloy Cladding and Assembly Components, sponsored by ASTM International Committee C26.13 and held on June 10-12, 2014, in Jackson, Wyoming. The potentially adverse impacts of hydrogen and hydrides on the long term performance of irradiated zirconium-alloy cladding on used fuel were shown to depend on multiple factors such as alloy chemistry and processing, irradiation and post irradiation history, residual and applied stresses and stress states, and the service environment. These factors determine the hydrogen content and hydride morphology in the alloy, which, in turn, influence the response of the alloy to the thermo-mechanical conditions imposed (and anticipated) during storage, transport and disposal of used nuclear fuel. Workshop presentations and discussions showed that although hydrogen/hydride induced degradation of zirconium alloys may be of concern, the potential for occurrence and the extent of anticipated degradation vary throughout the nuclear industry because of the variations in hydrogen content, hydride morphology, alloy chemistry and irradiation conditions. The tools and techniques used tomore » characterize hydrides and hydride morphologies and their impacts on material performance also vary. Such variations make site-to-site comparisons of test results and observations difficult. There is no consensus that a single material or system characteristic (e.g., reactor type, burnup, hydrogen content, end-of life stress, alloy type, drying temperature, etc.) is an effective predictor of material response during long term storage or of performance after long term storage. Multi-variable correlations made for one alloy may not represent the behavior of another alloy exposed to identical conditions and the material responses to thermo-mechanical exposures will be different depending on the materials and systems used. The discussions at the workshop showed several gaps in the standardization of processes and techniques necessary to assess the long term performance of irradiated zirconium alloy cladding during dry storage and transport. The development of, and adherence to, standards to help bridge these gaps will strengthen the technical basis for long term storage and post-storage operations, provide consistency across the nuclear industry, maximize the value of most observations, and enhance the understanding of behavioral differences among alloys. The need for, and potential benefits of, developing the recommended standards are illustrated in the various sections of this report.« less

Here we report on the construction and operation of a cross-linked aminated multi-walled carbon nanotube paper as a hydrogen sensor. The incorporation of palladium onto the surface of the paper resulted in p-type conduction as the resistance of the paper was measured, under exposure to hydrogen gas. When palladium nanocrystals were embedded into the cross-linked paper, n-type conduction was observed during hydrogen sensing. This investigation highlights the next stage in the development of functional nanotube paper.

Main characteristics of gaseous yield from steam gasification have been investigated experimentally. Results of steam gasification have been compared to that of pyrolysis. The temperature range investigated were 600–1000 °C in steps of 100 °C. Results have been obtained under pyrolysis conditions at same temperatures. For steam gasification runs, steam flow rate was kept constant at 8.0 g/min. Investigated characteristics were evolution of syngas flow rate with time, hydrogen flow rate and chemical composition of syngas, energy yield and apparent thermal efficiency. Residuals from both processes were quantified and compared as well. Material destruction, hydrogen yield and energy yield is better with gasification as compared to pyrolysis. This advantage of the gasification process is attributed mainly to char gasification process. Char gasification is found to be more sensitive to the reactor temperature than pyrolysis. Pyrolysis can start at low temperatures of 400 °C; however char gasification starts at 700 °C. A partial overlap between gasification and pyrolysis exists and is presented here. This partial overlap increases with increase in temperature. As an example, at reactor temperature 800 °C this overlap represents around 27% of the char gasification process and almost 95% at reactor temperature 1000 °C.

Conventional gas chromatography (GC) analysis of hydrocarbons displaying one broad peak provides limited information. Two GC analytical protocols using two-peak and three-peak approaches were developed to investigate transformer oil components and their degradation in soil by hydrogen peroxide. The two-peak method revealed transformer oil to be composed of 27 wt.% F2 fraction and 73 wt.% F3 fraction hydrocarbons. The three-peak method segregated the transformer oil into 40 wt.% light, 40 wt.% medium, and 20 wt.% heavy hydrocarbon fractions. In contrast to reports of success with several classes of lighter hydrocarbons, only limited degradations of transformer oil in soils by 15% and 30% hydrogen peroxide treatment was indicated by conventional one-peak analysis; two-peak analysis showed varying F2 and F3 fraction degradations with F2 fraction degradation being higher; three-peak analysis offered a richer understanding of the relative degradations of light, medium, and heavy fractions. The effect of a low pH environment on the degradation of transformer oil by hydrogen peroxide was evaluated using the three-peak method. It emerged that the degradation of the medium and heavier fractions of transformer oil was higher at pH 2.0.

We show that the non-spherical charge distribution of the proton manifests itself in hydrogen hyperfine splitting as an increase (in absolute value) of the proton Zemach radius and polarization contributions.

Recently, thinner cover glass is required therefore the glass strength is more important. It was found that surface polishing after chemical strengthening improved surface strength. In chemical strengthening process hydrogen enters the glass surface and creates chemical defects. Surface strength is improved by removing them.

Two mesophilic anaerobic bacterial strains (Z7T and Z1) were isolated from waste water sludge of the Xinanzhang paper mill, Beijing, China. The strains were Gram-positive, non-spore-forming and motile. Cells were thin rods (0·2–0·4×4·0–8·0 μm). Growth of the strains was observed at 20–42 °C and pH 5·0–7·5. Both strains hydrolysed gelatin and aesculin and fermented several kinds of mono-, di- and oligosaccharides. The fermentation end products formed from glucose were acetate, ethanol, hydrogen and carbon dioxide. The predominant cellular fatty acids were the branched-chain fatty acids isoC15 : 0 (42·83 %) and isoC14 : 0 (32·11 %). The DNA G+C contents of strains Z7T and Z1 were 50·4 and 48·6 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolates represent a new phyletic sublineage within the Clostridium leptum rRNA cluster, with Acetanaerobacterium elongatum gen. nov., sp. nov., a novel genus and species, is proposed, with strain Z7T (=JCM 12359T=AS 1.5012T) as the type strain.

The interactions of SO 2 and O 3 with fresh or aged bleached softwood pulp have been investigated using two techniques. The dry deposition of SO 2 (g) on paper was studied using on-line gas analysis. Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectrometry was applied in situ to characterise the paper surface during exposure to the pollutants. The DRIFT technique is shown to be sensitive enough to measure very small changes on the paper surface. The initial reaction on paper subjected to SO 2 and O 3 is shown to be the protonation of carboxylate groups present on the fibre, the hydrogen ions being added through the interaction of SO 2 with the moisture present in the paper. Results supportive of the protonation are produced by exposure of the aged paper to NH 3 (g). The results show that the combination of these techniques has a potential to show the degradation chemistry of paper under ambient conditions.

It is shown that the title paper reported by M.M. Wezhli et al. (Optik 127 (2016) 4258–4260) is completely erroneous. The so-called “glycine oxalate dihydrate” crystal is not a new crystal but instead is the well-known anhydrous glycinium hydrogen oxalate crystal.

IGZO TFTs are promising candidates to drive future high performance AM LCDs. Since IGZO is known to be sensitive to hydrogen new deposition processes for the adjacent dielectric thin films are needed. We developed a full-reactive hydrogen-free sputter process for SiO2 which shows a performance comparable to the state-of-art CVD dielectrics. We demonstrated that our sputtered SiO2 thin films are stable to electric fields of above 10 MV/cm and show leakage currents below 10−8 A/cm2 at 6 MV/cm.

Liquid scintillator (LS)-encapsulated silica was prepared by the sol-gel method and then was added dropwise onto a wipe paper to form a paper scintillator. First, the efficiencies of wipe were determined for both the paper scintillator and the wipe paper using a liquid scintillation counter (LSC). The efficiencies of wipe using the paper scintillator and the wipe paper were 88 and 36 %, respectively. The detection efficiencies were 5.5 % for the paper scintillator, 46 % for the wipe paper using an LS and 0.08 % for the (3)H/(14)C survey meter, respectively, compared with that of a melt-on scintillator of 47 %. Second, an (3)H contaminant on the paper scintillator was successfully detected using a photomultiplier without an LSC or an (3)H/(14)C survey meter. Finally, the paper scintillator was able to detect beta rays of the (3)H contaminant easily without an LS.

マグネシウムハイドライド（MgH2）の初期の低いクーロン効率を改善するために，マグネシウムハイドライドに5 mol% の五酸化ニオブ（Nb2O5）を添加し，これを電極とした全固体リチウムイオン電池を作製した。五酸化ニオブを1 mol% および5 mol% 添加したマグネシウムハイドライド（99MgH2-1Nb2O5，95MgH2-5Nb2O5）並びに固体電解質はメカニカルボールミリングによってそれぞれ合成した。MgH2，99MgH2-1Nb2O5，95MgH2-5Nb2O5 からの水素放出温度は昇温脱離質量分析によって測定した。また，95MgH2-5Nb2O5 の充放電測定は，電流密度を0.05 mA cm-2，0.15 mA cm-2 として100℃の温度条件下で行った。その結果以下が明らかとなった。（1）MgH2 の水素放出温度はNb2O5 の添加量が増加するのにつれて低下する。また，クーロン効率はNb2O5の添加量が増加するのにつれて向上する。従って，クーロン効率はMgH2 の水素放出温度が低下するのにつれて向上するといえる。（2）MgH2 のレート特性もNb2O5 を添加することによって改善する。（3）MgH2 へのNb2O5 の添加効果は，熱力学的・電気化学的な理由からリチウム吸蔵反応よりリチウム放出反応の方が顕著になる。（4）リチウム吸蔵反応において，MgH2 へのNb2O5 の添加効果は電流密度が0.15 mA cm-2 の方が0.05 mA cm-2 よりも顕著になる。 このように，MgH2 の負極特性はNb2O5 を添加することによって改善する。, We fabricated an all-solid-state lithium ion battery with magnesium hydride (MgH2) anode which was catalyzed by doping 5mol% Nb2O5 (95MgH2-5Nb2O5) to increase low first-coulombic-efficiency of MgH2 anode. The catalyzed MgH2 (99MgH2-1Nb2O5, 95MgH2-5Nb2O5) and solid electrolyte were independently synthesized by mechanical ball milling. In order to investigate the hydrogen desorption temperature of pristine MgH2, 99MgH2-1Nb2O5 and 95MgH2-5Nb2O5, thermal desorption mass spectroscopy was carried out. In addition, the charge and discharge measurement for 95MgH2-5Nb2O5 was carried out at 100 ℃ and at current density of 0.05 mA cm-2 and 0.15 mA cm-2. As a result, the following results were revealed. (1) The hydrogen desorption temperature decreases with increasing Nb2O5 contents and columbic efficiency increases with increasing Nb2O5 contents. Therefore, the columbic efficiency increases with decreasing hydrogen desorption temperature. (2) Rate properties of MgH2 are also improved with increasing Nb2O5 contents. (3) Effect of Nb2O5 additives on anode properties of MgH2 is clearer upon the Li extraction reaction than that upon the Li insertion reaction due to thermodynamically and electrochemically reasons. (4) Upon the Li insertion reaction, effect of Nb2O5 additives become clearer at current density of 0.15 mA cm-2 than that of 0.05 mA cm-2. Thus, the anode properties of MgH2 are improved by adding Nb2O5.

Reference EPFL-ARTICLE-224875doi:10.1088/1361-6455/50/1/010201View record in Web of Science Record created on 2017-01-24, modified on 2017-01-26

The glass transition temperature in amorphous region of insulation paper is one of the most important characteristics for its thermal stability. In order to study the microscopic mechanism of the glass transition process for transformer insulation paper which may provide some information for thermal aging, molecular dynamic simulations has been performed on two micro-structural models: pure amorphous cellulose and amorphous cellulose with water. Using the method of specific volume versus temperature curve, the glass transition temperatures of pure cellulose and cellulose-water were determined as 448K, 418K respectively. Simulation results also show that during the glass transition process, both the chain movement (characterized by mean square displacement, end-to-end distance, and mean square bend) and mechanical properties of cellulose are changing significantly. The addition of water also reduces the mechanical strength of cellulose and increases its ductility and plasticity slightly. In addition, Fox and Flory's free volume theory was also used to explain the nature of glass transition which shows a sudden change of free volume between 400 K and 450 K that provides more space for chain movement. The water molecules that immersed in amorphous region of insulation paper can disrupt hydrogen bonds between cellulose chains, which lead to a significant reduction in glass transition temperature.

The remarks on the results published in [1–4] on the simulation of a copper vapour laser with hydrogen admixtures are analysed. It is shown that these remarks do not affect the conclusions made in our papers, and many of them are simply erroneous.

Alumina supported iridium catalysts used in satellite thrusters are prepared several years before satellite launch and the ageing of such catalysts is an important parameter for the lifetime of the satellite. The ageing has been studied using two procedures and different characterization methods: metal dispersion through hydrogen chemisorption followed by oxygen and hydrogen titrations, powder X-ray diffraction, transmission electron microscopy and catalytic activity in ammonia decomposition. Long term storage during six months and one year under static argon, air or hydrogen atmosphere led to the same slight decrease of the metallic dispersion. After accelerated ageing using dynamic oxygen or water vapor flow, the samples display the same dispersion drop and the same evolution of the crystallite size distribution with a drop of the smallest crystallites due to sintering effects or to formation of oxichloride surface species. The catalytic activity discloses a difference between the ageing treatments: the treatment with oxygen leads to an increase of the measured activity while a treatment with water vapor gives the opposite behavior. The removal of surface chloride ions stabilizes the catalyst against water vapor ageing effects without any modification of dispersion, size distribution and catalytic activity.

Gasification of biomass has become an area of key interest as it is a reasonably quick and direct way of converting the material into a fuel source that works directly in many industrial systems. The purpose of the present work is to explore gasification and pyrolysis behavior of corn kernels and paper sludge. For both corn kernels and paper sludge, low temperature gasification behavior was studied. Due to corn’s low ash fusion temperature, ∼1400 C, gasification is typically undertaken at temperatures near 1000 C, and most of the chemical mechanisms are similar down to ∼500 C. Here, tests were performed with pyrolysis temperatures from 400–800°C, at 1 atm and a rapid heating rate. The evolution of CO and CO2 were measured throughout the pyrolysis process. Results show a direct correlation between temperature and equivalence ratios and the composition of the gas byproduct for both biomasses. CO production increases with an increase in temperature while CO2 shows no temperature correlation. No hydrogen was observed, as would be expected for the short experimental residence time (0.2 seconds).Copyright © 2010 by ASME

Heavy water, D 2 O, was used in the preceding paper by Dytlewski et al. in a leaching experiment of the Australian titanate waste ceramic Synroc. The results were compared to previous data with H 2 O of the present authors. The leaching experiment in H 2 O was now repeated confirming the previous results. The small differences in these two types of experiments and the relevant features of the elastic recoil detection analysis, ERDA, are discussed.

The possibility of the formation of endohedral complexes between H 2 molecules and C 60 fullerene is discussed on the basis of general geometric considerations as well as the results of molecular mechanics calculations. The obtained results revealed that only one hydrogen molecule being incorporated inside the C 60 cage can form the stable complex in agreement with geometric considerations and recent experimental data. The reliability of semiempirical methods to study the problem of H 2 insertion into C 60 is also discussed.

Sheets made from untreated and treated wood and bagasse pulps were subjected to thermal degradation in static air and monitored by the differential thermal analysis (DTA) technique. Percent of resin (resol or novolac) added to the pulps was chosen on the basis that maximum breaking length was achieved. The DTA profiles were obtained and analyzed using the Prout-Tompkins law. A computer program was developed to elucidate the appropriate order of reaction (n) and, consequently, the thermodynamic parameters. Infrared spectra of the samples, and their relation with the mechanical properties and the above thermodynamic parameters, were elucidated. It was found that resin addition (either novolvac or resol) to bagasse pulp led to increased thermal stability, mean hydrogen strength, and crystallinity index. In addition, the stretching vibration corresponding to OH groups was shifted to a lower wavenumber due to its bonding with the phenolic resin. However, no significant changes were observed (specially...