SiO2–CaO–Na2O–P2O5–ZrO2 based bioactive glasses with different compositions of SiO2 and yttrium stabilized ZrO2 were prepared by the conventional melt quenching technique. The effects on the chemical–mechanical properties of bioactive glasses due to the addition of ZrO2 by replacing SiO2 were investigated. Microstructure and phase behavior were studied by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction analysis. Compressive strength, porosity, Vickers hardness, and Young’s modulus were measured as mechanical properties. Bioactivity and cell viability were investigated by immersion in simulated body fluid and MTT assay analysis. Osteosarcoma cell proliferation on the specimen surfaces was examined by confocal laser scanning microscopy. The results showed that replacing SiO2 with ZrO2 helps the bioactive glass to be completely vitrified at comparatively lower sintering temperature than conventional Bioglass®. The mechanical properties were also improved without compromising biocompatibility. Bioactive glass containing 10 wt% ZrO2 and 35 wt% SiO2 showed compressive strength of 399.71 MPa, Young's modulus of 22.3 GPa, Vicker’s hardness of 502.54 HV, and porosity of 26 vol%. 相似文献
The paper is focused on studies of channel viscous flow stability with the high dependence viscosity on temperature (thermoviscosity effect). It is shown the essential influence of this effect on the entrance length or transition from any initial profile to the stationary profile of the plane channel flow. The obtained solution has an inflection point in the velocity profile for the certain range of flow parameters. This evidence with respect to Rayleigh’s inflection theorem involves thermoviscous media deserving consideration objects for stability problems. 相似文献
Through‐silicon via (TSV) technology provides much of the benefits seen in advanced packaging, such as threedimensional integrated circuits and 3D packaging, with shorter interconnection paths for homo‐ and heterogeneous device integration. In TSV, a destructive cross‐sectional analysis of an image from a scanning electron microscope is the most frequently used method for quality control purposes. We propose a quantitative evaluation method for TSV etch profiles whereby we consider sidewall angle, curvature profile, undercut, and scallop. A weighted sum of the four evaluated parameters, nominally total score (TS), is suggested for the numerical evaluation of an individual TSV profile. Uniformity, defined by the ratio of the standard deviation and average of the parameters that comprise TS, is suggested for the evaluation of wafer‐to‐wafer variation in volume manufacturing. 相似文献
Two-finger operations, such as rotation operations and zoom operations, are now standard touchscreen operations. However, these two-finger operations may pose an ergonomic problem when they are performed with one hand. FingerSkate is an interaction technique to mitigate the ergonomic problem of two-finger operations adopting the concept of gesture relaxation. A preliminary study showed that the FingerSkate technique was accepted well by the participants. In particular, a micro-analysis of finger movements during the study showed that FingerSkate was utilized well for large rotations. In a subsequent user study, the effects of two FingerSkate design options, Concurrency and Pivot, were examined. The Concurrency option had a statistically significant effect on performance and task workload for a docking task. The Pivot option had a statistically significant effect on task workload for a puzzle task. More participants preferred the sequential Concurrency option, and most participants preferred the center-of-object Pivot option. 相似文献
The results of experimental investigation of the DC electrical discharge with moving air bubbles in the electrolyte, as well as of high frequency electrical discharge with a diaphragm membrane, within a wide parameter range are presented. We investigated active component formation and enhancement of the wastewater decontamination by means of production of a disinfecting agent with a maximal content of the electrical discharge products (copper and silver ions and hydrogen peroxide). 相似文献
In this research, p‐type Bi2Te3–75% Sb2Te3 thermoelectric alloy powders were produced by gas atomization and subsequently sintered by hot pressing at different temperatures. The grain growth of the hot‐pressed samples was observed with increasing sintering temperature from 380°C to 460°C. The compressive strength increased with increasing hot‐pressing temperature due to the high relative density of bulk samples obtained at high temperatures. The effect of sintering temperature on thermoelectric (TE) properties was studied. The maximum power factor 3.48 mW/mK2 was obtained for the sample hot pressed at 420°C due to the resulting high electrical conductivity and enhanced Seebeck coefficient values. 相似文献
An efficient phosphaannulation via palladium(II)‐catalyzed C H activation/oxidative cyclization by the 6‐endo mode is reported for the synthesis of 3‐substituted phosphaisocoumarins from the reaction of arylphosphonic acids with unactivated alkenes under aerobic conditions. Also, α,α‐disubstituted benzylphosphonic acids were phosphaannulated with unactivated alkenes, producing phosphaisochromanones having (Z)‐alkylidenyl groups via anti‐phosphoryloxypalladation by the 6‐exo mode.
Maleated poly(lactic acid) (PLA-g-MA) was prepared through melt grafting of maleic anhydride onto a PLA backbone with the aid of a radical initiator. PLA-g-MA thus formed was incorporated into PLA/polyamide 11 (PA11) blends as a reactive compatibilizer. By morphological observation, it was assessed that PLA-g-MA lowered the interfacial energy and strengthened the interface between PLA and PA11. However, the compatibilized PLA/PA11 blends did not show significant improvement of impact strength compared with noncompatibilized PLA/PA11 blends. Measurements of the molecular weight and impact strength of PLAs compounded with various amounts of radical initiators revealed that decreased molecular weight of PLA by the radical initiator used for the preparation of PLA-g-MA is responsible for this unexpected result. To compensate the decrease of the molecular weight, a crosslinking agent was incorporated in the preparation step of PLA-g-MA. It was found that the crosslinking agent is effective in preventing the molecular weight reduction. As a result, the impact strength of the PLA/PA11 blend was enhanced to a great extent by the PLA-g-MA prepared with the crosslinking agent. 相似文献