Driving the field of micro computed tomography toward more quantitative, rather than qualitative, approaches, we here present a new evaluation method, which uses the unique linear relationship between gray values and x-ray attenuation coefficients, together with the energy-dependence of the latter, to identify (i) the average x-ray energy used in the CT device, (ii) the x-ray attenuation coefficients, and (iii), via the x-ray attenuation average rule, the intravoxel composition, i.e., the microporosity, which, amongst others, governs the voxel-specific mechanical properties, such as stiffness and strength. The method is realized for six 3D tricalcium phosphate scaffolds, seeded with pre-osteoblastic cells and differentiated for 3, 6, and 8 weeks, respectively. The corresponding voxel-specific microporosities turn out to increase during the culturing period (resulting in reduced elastic properties, as determined from micromechanical considerations), while the overall macroporosity remains constant. The new methods are expected to further foster the development of a rationally based and computer-aided design of biomaterials and tissue engineering scaffolds.

In this article, monolithic porous silsesquioxane materials, which are derived by sol–gel from trialkoxysilanes with substituent groups such as trimethoxysilane (HTMS), methyltrimethoxysilane (MTMS), and vinyltrimethoxysilane (VTMS), are reviewed with a special emphasis on our recent works. Careful controls over fundamental synthetic parameters such as pH, amounts of water and solvent, and kind of solvent and additives play a crucial role in the formation of monolithic gels based on random polysiloxane networks. Crystalline/amorphous precipitation is otherwise observed when the formation of isolated species including polyhedral oligomeric silsesquioxanes dominates or if phase separation of the hydrophobic networks in aqueous media is not adequately controlled. In the successfully controlled system, pore size can be varied from a few tens of nanometers to a few tens of micrometers; porous materials such as transparent aerogels and hierarchically porous monoliths have been explored. In addition, unique properties derived from trialkoxysilanes such as reactivity of the pore surface and flexible mechanical properties are demonstrated. Possibilities in the silsesquioxane materials with controlled pore structures are discussed.

Comprehensive intermetallic compound phase analysis at wire bond interfaces was performed for a side-by-side comparative study between 18 µm Pd-only coated Cu wire and 18 µm Pd-coated Cu wire followed by Au flash coating. Scanning electron microscopy and transmission electron microscopy results combined with nanobeam electron diffraction and structure factor calculation identified the formation of metastable θ′-CuAl2 and Cu9Al4 in both of the wire bonds before and after high temperature storage test. In particular, nanobeam electron diffraction and structure factor calculation unambiguously revealed that the two intermetallic compound phases grow in size after high storage temperature test in a manner that they maintain their epitaxial relationships that minimize lattice mismatch at the Cu/Al wire bond interface. Nanobeam electron diffraction and energy dispersive x-ray spectroscopy results found no significant Au flash coating effects in terms of intermetallic compound morphology, phase, and thermal evolution.

Aiming to clarify the effects of initial states on hot deformation behavior of a powder metallurgy nickel-based superalloy FGH96, specimens in hot isostatic pressed (HIPed) and solution states were isothermally compressed in the temperature range of 1000–1150 °C and the strain rate range of 0.001–1.0 s−1. It revealed that the flow behavior of FGH96 was dependent on the initial states, in which the deformation resistance was higher in the solution state than that in the HIPed state at evaluated temperatures, and the differences became less when the temperature was higher than the γ′ dissolution temperature. The calculated hot activation energy using peak stresses are 590 and 1285 kJ mol−1 for HIPed and solution specimens. Comparison with HIPed specimen, the efficiency of power dissipation (η) in solution specimen is less, and the optimum workability regime moves to higher temperatures. Cracking and in-grain shear bands were observed in the specimens when compressed in flow instability areas.

The influence of aging treatment on shape memory effect (SME) and wear resistance of Fe–20Mn–5Si–10Cr–5Ni–0.7V–0.2N (mass%) alloy was investigated. Results showed that vanadium nitride (VN) particles precipitated during aging treatment, and the amount and size of the particles increased with increasing aging time. The sample aged for 8 h exhibited the maximal shape recovery ratio of 74% (compared with that of 16% for unaged) and favorable wear resistance in both dry wear and oil-lubricant wear conditions. The fine VN particles are the key factor to improve the SME by strengthening the alloy and acting as preferential nucleation sites for martensite. However, more and larger particles due to further aging treatment appeared to have negative effects on the SME and wear resistance. After oil-lubricant friction, there existed large amounts of friction-stress-induced ε martensite in the worn surface of the sample. As a result, the wear resistance of samples in oil-lubricant wear condition was remarkably higher than that in dry wear condition.

Fibrous polyethylene terephthalate (PET) was modified by organometallic vapor exposure to form hybrid materials with unique photoluminescent characteristics. Using a sequential vapor infiltration (SVI) process, the elongated exposures of trimethylaluminum (TMA) to PET were examined. As the infiltration temperature increased, the evidence of changes in the reaction between the organometallic vapor and the polymer was observed as well as significant changes in the infiltration depth into the polymer fiber, owing to the variation in the reaction mechanisms of the hybrid material formation. At TMA exposures of 60 °C, the mass of the polymer fiber increased by ∼55 wt%, whereas exposures at 150 °C were limited to ∼25 wt% infiltration. Photoluminescence analysis of PET after TMA infiltration shows an intensity increase of up to ∼13x and an increase in red shift with increasing infiltration temperature, attributed to the variations in the reaction mechanism to form the hybrid modification observed through the spectroscopy analysis.

The thickness dependence of the electrical stability under monotonic and cyclic tensile loading is investigated for Cu films on polymer substrates. As for monotonic tensile deformation, thicker films show better stability than thinner films due to their higher ductility and the larger capability of strain accommodation. For the fatigue resistance, however, a more complex behavior was observed depending on the amount of the applied strain. For low strain amplitude in the high cycle fatigue (HCF) regime, thinner films exhibit longer fatigue life because the larger strength of thinner films suppresses dislocation movement and damage nucleation. However, for high strain amplitudes in the low cycle fatigue (LCF) regime, the fatigue life for thinner films is drastically reduced compared to thicker films. It is shown that fatigue coefficients in the LCF regime can be obtained when applying the Coffin–Manson relationship.

Conjugated polymer films are of considerable current interest for functionalizing the surfaces of a wide variety of devices including implantable biomedical electronics. Toward these ends, copolymer films of 3,4-ethylenedioxythiophene (EDOT) with a carboxylic acid functional EDOT (EDOTacid) were electrochemically deposited and characterized as a systematic function of the EDOTacid content (0, 25, 50, 75, and 100%). Chemical surface characterization of the films confirmed the presence of both EDOT and EDOTacid units. Toluidene blue assays showed that the surface concentration of the carboxylic acid groups increased to a maximum of 2.75 nmoles/mm2, and the contact angle measurements confirmed the increased hydrophilicity of the films with increasing EDOTacid content (decreasing from 52.6 to 32.5 degrees). Cyclic voltammetry showed that the films had comparable charge storage capacities regardless of their composition. The morphology of the films varied depending on the monomer feed ratio. The addition of EDOTacid induced a transition from a nodular, porous surface to a more dense, pleated surface structure. These methods provide a facile means for synthesizing electrically active carboxylic acid functional poly(3,4-ethylenedioxythiophene) copolymer films with tunable hydrophilicity and surface morphologies.

This study demonstrates a highly sensitive humidity sensor based on treated multiwalled carbon nanotube (tr-MWCNT) and hydroxyethyl cellulose (HEC) composite films. Tr-MWCNTs are obtained by mixed acid treatment to enhance their hydrophilicity and improve their dispersion in distilled water. Compared to tr-MWCNT/silicone rubber (SR) composite film, the humidity sensitivity of tr-MWCNT/HEC film is much higher than tr-MWCNT/SR film with the same film thickness. The humidity sensing mechanisms of tr-MWCNT/HEC composites are explained by electron donation model and swelling mechanism. Speaking and blowing experiments were also carried out and the results show that tr-MWCNT/HEC composite film is sensitive to both speaking and blowing; furthermore, it can distinguish the small humidity level difference between speaking and blowing. Other sensing characteristics, including response and recovery time, stability, and temperature effect, are also investigated. The high humidity sensitivity of tr-MWCNT/HEC composite film indicates that it can be an excellent humidity sensitive material.

We use transmission electron microscopy (TEM) for in situ studies of electron-beam-induced crystallization behavior in thin films of amorphous transition metal silicon carbides based on Zr (group 4 element) and Nb (group 5). Higher silicon content stabilized the amorphous structure while no effects of carbon were detected. Films with Nb start to crystallize at lower electron doses than the Zr-containing ones. During the crystallization, equiaxed MeC grains are formed in all samples with larger grains for ZrC (∼5 nm) compared to NbC (∼2 nm). The phenomenon of self-terminating crystallization at a dimension of 2–5 nm is explained by segregation of Si that is expelled from growing metal carbide grains into the surrounding amorphous phase matrix, which limits diffusion of the metal and carbon.

Our research aims at exploring a new oxygen reduction reaction (ORR) catalyst with effective catalytic capability, which can be used in the metal-air batteries. ORR electrocatalysts of carbon black and carbon aerogel supported Pt-based nanoparticles were synthesized by a chemical impregnation reduction method. The electrochemical measurement consisted of cyclic voltammetry (CV) and line scan of scanning electrochemical microscopy (SECM) conducted in alkaline medium as well as the single-cell tests. All the tests indicate that the Pt–Zn/carbon aerogel (Pt–Zn/CA) catalyst, with the specific discharge capacity reaching 1349.5 mA h g−1, exhibits the best catalytic performance among all the tested catalysts. The doping of Zn forms Pt-rich surface, creates more d-band vacancies, and reduces the leaching problem; the use of carbon aerogels brings larger specific surface area. These aspects have all improved the catalytic activity per unit mass.

The grain size dependence of the radiation response of silicon carbide (SiC) has been studied under 1.0 MeV Kr2+ ion irradiation. It was found that radiation resistance decreased with grain refinement, in contrast to previous studies on the same nanocrystalline (nc) SiC material using Si ion and high voltage electron irradiation. The effect of grain size on radiation response may depend upon the ion species used due to a potential change in amorphization mechanism. It was also determined that temperature had a strong effect on the grain size dependence of the radiation response in SiC due to the activation temperatures of critical recombination and migration reactions. This work explores the possible impacts of irradiation species, temperature, and experimental design on the radiation response of SiC.

Nanoporous carbon membranes (NCMs) were fabricated by the blends of resorcinol–formaldehyde (RF) resin and Pluronic F-127 through the processes of assembly, membrane-casting, solidification, and pyrolysis. The effect of the catalyst type (i.e., NaOH and Na2CO3) on the structure and property of precursors and their derived NCMs was investigated. The as-obtained precursors and NCMs were characterized by thermogravimetry, differential scanning calorimetry, x-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, elemental analysis, nitrogen adsorption, and gas permeation techniques. The results have shown that defect-free NCMs can be easily procured by the NaOH and Na2CO3 catalysts. In contrast, the precursor made from the Na2CO3 catalyst exhibits higher char yield than that from NaOH after pyrolysis. NaOH-based NCMs are beneficial for the separation of H2/N2 and CO2/N2 gas pairs. Na2CO3-based NCMs are more favorable for the separation of O2/N2 with an ideal selectivity of 6.29 and an O2 permeability of 3.27 Barrer.

Practical implementation of oxide thermoelectrics on an industrial or commercial scale for waste heat energy conversion requires the development of chemically stable interfaces between metal interconnects and oxide thermoelements that exhibit low electrical contact resistances. A commercially available high-chrome iron alloy (i.e., Crofer® 22 APU) serving as the interconnect metal was spray coated with LaNi0.6Fe0.4O3 (LNFO) or (Mn,Co)3O4 spinel and then interfaced with a p-type thermoelectric material—calcium cobaltate (Ca3Co4O9)—using spark plasma sintering. The interfaces have been characterized in terms of their thermal and electronic transport properties and chemical stability. With long-term exposure of the interfaced samples to 800 °C in air, the cobalt–manganese spinel acted as a diffusion barrier between the Ca3Co4O9 and the Crofer® 22 APU alloy resulting in improved interfacial stability compared to that of samples containing LNFO as a barrier layer, and especially those without any barrier. The initial area specific interfacial resistance of the Ca3Co4O9/(Mn,Co)3O4/Crofer® 22 APU interface at 800 °C was found to be ∼1 mΩ·cm2.

By combining two types of ligands, phenylpyridine and quinoline, a new type of organometallic IrQ(ppy)2 compound has been synthesized, which exhibits two phosphorescences: green and red. Using an appropriate catalyst, the final IrQ(ppy)2 compound has a good chemical yield up to 60% and becomes a stable dual emitter at room temperature. This compound is important because it exhibits stable red emission which is limited by the quantum yield due to the low energy band gap. As a result, an overlap between the ground state and the excited state occurs due to the vibrations that increase the nonradiative transitions, destroying the red emissions. Structural characteristics of the IrQ(ppy)2 powder reveal a triclinic structure confirmed by x-ray diffraction and scanning electron microscopy images. Thermal analysis of the final compound confirms a good stability against decomposition and structural changes up to 350 °C. X-ray photoelectron spectroscopy reveals Ir–O chemical bonds and several differences between the intermediate and final compounds, such as Ir–Cl bonds. Cathodoluminescence patterns show a phosphorescent triclinic structure with a higher efficiency for the red color. Backscattering electron images prove that there is a uniform distribution of iridium ions in the IrQ(ppy)2 nanocrystals.