Search

Copyright of Strahlentherapie und Onkologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The adsorption of hydrogen molecule on a novel structure of Ti containing organometallic complexes grafted on silsequioxanes (SQ, HSiO) was investigated by means of DFT method. The hydrogen adsorption properties of the complex structures TiRHSiO (R = CH, CH, CH) keep almost the same as that of corresponding Ti containing organometallic complexes. Moreover, these complex structures can avoid the problem of transition metal clustering which is a disadvantage for hydrogen adsorption. The maximum number of hydrogen molecules adsorbed was still determined by 18 electron rule, that is to say 5, 4, and 4 H molecules for TiRHSiO with R = CH, CH, and CH, respectively. At the same time, all the average binding energy of H is located in 0.2-1.0 eV, which is an advantage for hydrogen storage at ambient conditions. Therefore, the materials studied here may provide some enlightenment for developing new types of hydrogen storage materials. [ABSTRACT FROM AUTHOR]

The current of the outward K channel in the cell of horseradish treated with La and the direct interaction between La and the K channel protein were investigated using the whole-cell patch-clamp technique, molecular dynamics simulation, and quantum chemistry calculation methods. It was found for the first time that La decreases the current of the K channel in the horseradish mesophyll cell. The decrease results from the formation of a coordination bond and hydrogen bond between La and the K channel protein in the plasma membrane. The direct interaction destroys the native structure of the K channel protein, disturbing the function of the K channel protein in the cells. The results can provide the theoretical foundation for understanding the interaction between metal ions (especially high-valence metal ions) and the channel protein in organisms, including animal and plant cells. [ABSTRACT FROM AUTHOR]

In this communication, we report on the attempt to make full use of the off-gases from polycarbosilane-derived SiC preparation, and we successfully synthesized long SiC nanowires in large areas with Fe(NO3)3 as catalyst. The nanowires have diameters of about 80–300 nm and lengths of millimeters, and they are identified as single crystals β-SiC along the 〈111〉 direction. The VLS mechanism was employed to interpret the nanowire growth. [ABSTRACT FROM AUTHOR]

Long silicon nitride (Si3N4) nanowires with high purity were synthesized by heating mixtures of SiO2 powders and short carbon fibers at 1430°C for 2 h in a flowing N2 atmosphere. The nanowires had the length of 1–2 millimeters and the diameters of 70–300 nm, and were mainly composed of ⍺-Si3N4, growing along the [001] direction. The vapor–solid (VS) mechanism was employed to interpret the nanowires growth. [ABSTRACT FROM AUTHOR]

The high-temperature resistant Si–Al–C–(O) fibers were prepared through polymer-derived method using continuous polyaluminocarbosilane (PACS) fibers. Evolutions of the crystallization during the pyrolysis of the Si–Al–C–(O) precursor fibers were investigated by a series analysis. The structure of the fibers transforms from organic state to inorganic state and the crystalline phases appear during the pyrolysis. The β-SiC crystallite size increases when the temperature is higher than 1,300 °C. At the same time, the α-SiC appears. At 1,600 and 1,800 °C, the grain size of β-SiC of the fibers is 15.4 and 22.1 nm, respectively. The growth of β-SiC and the appearing of α-SiC have a great influence on the properties of the fibers. The change of the tensile strength of the pyrolysis products is divided into three stages with the growth of the crystal. The tensile strength of the Si-Al-C fibers is higher than 1.9 GPa. [ABSTRACT FROM AUTHOR]

The dependence of gliding arc gas discharge characteristics, including gas flow field, arc column motion and volatile organic compounds (VOCs) decomposition performance, on reactor configuration parameters was investigated based on numerical simulation and laboratory experimental findings. For a given supply voltage (10 kV) and a certain nozzle outlet diameter (1.5 mm), increasing the electrodes gap (1–4 mm) or decreasing vertical distance between electrode throat and nozzle outlet (25–10 mm) will increase the gas flow rate through the electrode throat, the gas velocity in the plasma region, the arc column velocity, the maximum attainable position of the arc column and the electrical power consumption, also, higher VOCs decomposition rate and lower specific energy requirement are observed according to the n-butane and toluene decomposition experiments. [ABSTRACT FROM AUTHOR]

A novel method was introduced to prepare open-cell Al2O3–ZrO2 ceramic foams with controlled cell structure. This method used epispastic polystyrene (EPS) spheres to array ordered templates and centrifugal slip casting in the interstitial spaces of the EPS template to obtain cell struts with high packing density. Aqueous Al2O3–ZrO2 slurries with up to 50 vol.% solid contents were prepared and centrifuged at acceleration of 2,860 g. The effect of the solid contents of slurries on segregation phenomena of different particles and green compact uniformity were investigated. In multiphase system, the settling velocities of Al2O3 and ZrO2 particles were calculated. Theory analysis and calculated results both indicated segregation phenomenon was hindered for slurries with 50 vol.% solid content. The cell struts of sintered products had high green density (61.5%TD), sintered density (99.1%TD) and homogeneous microstructures after sintered at 1,550 °C for 2 h. The cell size and porosity of Al2O3–ZrO2 ceramic foams can be adjusted by changing the size of EPS spheres and the load applied on them during packing, respectively. When the porosity increased from 75.3% to 83.1%, the compressive strength decreases from 3.82 to 2.07 MPa. [ABSTRACT FROM AUTHOR]

In the preparation of Nicalon-type Si-C-O fibers using a normal-pressure synthesized polycarbosilane precursor, a network of microflaws were detected on the cross-section of ceramic fibers obtained. Cross-section morphologies of the interior microflaws were investigated via SEM technique after certain temperature pyrolysis and their initiation and propagation behaviors were studied accordingly. The results showed that no microflaws came into being at the temperature up to 600°C due to the organic nature of the material. As a result of high weight loss and composition change, however, microflaws initiated over 600°C, formed at ∼700°C and propagated along the "core-edge" direction from 700-900°C. Up to 1100°C, a microflaw network was formed because new microflaws generated across the oriented ones and interconnected them to form a network. [ABSTRACT FROM AUTHOR]

Defects of polymer-derived Si−C−O fibers were intensively studied by the SEM and TEM techniques and their originations were also discussed on the basis of factors experiments. The defects were found mainly in the form of strumaes, pits and splits on surfaces as well as microflaw networks, porosity clusters and inclusions in the bulk. Factors experiments reveal that a nonuniform or an insufficient curing would result in larger-sized strumaes or interior microflaws. Gas evolution rates due to different firing rates have a great influence on the formation of internal microflaws or porosity clusters and some oxidation-induced pits or splits may be formed on surfaces because of a trace of oxygen or water vapor accumulated from the flowing inert atmosphere during pyrolysis. [ABSTRACT FROM AUTHOR]

Incineration as a method of reducing Municipal Solid Waste (MSW) volume and recovery of energy has been developed gradually in China. More attention is paid on polychlorinated dibenzo- p-dioxins and polychlorinated dibenzofurans, (PCDD/Fs) formed in MSW incineration process. This paper presents results of the analysis of PCDD/Fs in the residues of a fluidized bed incinerator co-firing MSW and coal in the Yuhang Thermal Power Plant. The effects of operation conditions and the wet scrubber system on PCDD/Fs formation were also analyzed. PCDD/Fs emitting from the smoke stack was 0.92 I-TEQ ng/Nm3. After the wet scrubber emission of dioxins increased and the shifting of homologue profiles in flue gas was also observed, PCDFs were not detected in the incinerator residues. From this, we can see that in the MSW incineration process, the formation mechanism of PCDFs was different from that of PCDDs. The results will benefit further research on the optimal operation of incinerator and control of PCDD/Fs emission from the MSW incinerator. [ABSTRACT FROM AUTHOR]