Herein rutile (TiO2) single-crystal surfaces, with (001) and (100) orientations, were indented with hemispherical indenters with radii of 13.5, 5, and 1.4 μm. By converting the load–displacement data to nanoindentation (NI) stress–strain curves, together with microscopic post-indentation observations, we conclude that in the (001) orientation, plastic deformation occurs by the activation of all four {101}<10> slip systems. In the (100) orientation, only two of the four {101}<10 > slip systems, along with {100}<00> slip, are activated. Because the four {101}<10> slip systems in the (001) orientation intersect, the surface is harder and exhibits higher hardening rates after the nucleation of dislocations. The latter are manifested by pop-ins, some of which are large. The pop-in stresses are adequately described by Weibull statistics and were significantly higher for the (001) orientation. The elastic moduli, determined from spherical NI stiffness versus contact radii plots, were 349 ± 5 and 229 ± 4 GPa for (001) and (100) orientations, respectively. Fully spontaneous reversible, stress–strain hysteretic curves—only manifest in the (100) orientation—are attributed to the to-and-fro motion of dislocations comprising incipient kink bands in the {100}<00> slip system.

Electropulsing treatment (EPT) has been first applied to the recrystallization of a refractory metal—tungsten (W). We have three major observations: (i) the recrystallization temperature of a rolled pure W under EPT is ∼900 K higher than its conventional recrystallization temperature (1603 K); (ii) the time required for recrystallization is significantly reduced compared with that of conventional heat treatment (CHT); (iii) the recrystallized grains are also much finer than the ones under CHT. Based on quantitative analysis, we conclude that the huge increase of the recrystallization temperature of the rolled pure W under EPT is due to the high heating rate generated by EPT and high activation energy for vacancy diffusion of W, and the accelerated recrystallization and grain refinement have resulted from the coupling of thermal and electromigration effects of EPT at relatively high temperatures.

In this work, the ultimate bending strengths of as-grown Si and fully oxidized Si nanowires (NWs) were investigated by using a new atomic force microscopy (AFM) bending method. NWs dispersed on Si substrates were bent into hook and loop configurations by AFM manipulation. The adhesion between NWs and the substrate provided sufficient restraint to retain NWs in imposed bent states and allowed subsequent AFM imaging. The stress and friction force distributions along the bent NWs were calculated based on the in-plane configurations of the NWs in the AFM images. As revealed from the last-achieved bending state, before fracture, fracture strengths close to the ideal strength of materials were attained in these measurements: 17.3 GPa for Si NWs and 6.2 GPa for fully oxidized Si NWs.

We propose a new method of synthesis of crystalline yttrium and lutetium orthoborates in thin (2.5–20.0 μm thick) layers of molten borate oxide glasses. The method is based on interaction of nanosized lutetium and yttrium oxide powders with boron anhydride in the melt. X-ray diffractometry and electron microscopy investigations have revealed that in the case of lead-content glasses, the method shows a very strong orienting effect in the texture of the resulting orthoborate particles. This highly oriented texture results in good transparency of the obtained glass–ceramic films. Studies of the luminescence and scintillation spectra of the glass–ceramic composites show that they can be used as highly effective phosphors with a light yield comparable to that of single crystalline scintillators.

The temperature dependence of diffusion length, lifetime, and diffusivity of the free exciton is measured in a commercial ZnO-substrate as well as in an epitaxial ZnO quantum well using nm-spatially and ps-time-resolved cathodoluminescence spectroscopy. The characteristic temperature dependence of the exciton mobility gives information of the underlying excitonic scattering processes. Since excitons are neutral particles, scattering at ionized impurities should be not effective. On both samples, with decreasing temperature, the diffusion lengths, lifetimes, and diffusivity give rise to a monotonic increase of the excitonic mobility. Two different methods will be discussed and are used for determining the excitonic transport parameters. On the one hand, we are able to perform completely pulsed excitation experiments, and on the other hand, a combination of cw excitation and pulsed excitation in two independent measurements is used.

Calcium vanadate nanorods with Ca10V6O25 phase have been synthesized by a hydrothermal process without any surfactants. Hydrothermal temperature, reaction time and calcium (Ca) raw materials play important roles in the formation and size of the calcium vanadate nanorods. The nucleation and crystal growth combined with crystal splitting process have been proposed to explain the formation and growth of calcium vanadate nanorods. The calcium vanadate nanorods are used as glassy carbon electrode-modified materials to analyze the electrochemical behaviors of tartaric acid. The calcium vanadate nanorod-modified glassy carbon electrode exhibits good performance for the electrochemical detection of tartaric acid with a detection limit of 2.4 μM and linear range of 0.005–2 mM. The analytical performance and straightforward fabrication method make the calcium vanadate nanorods promising for the development of electrochemical sensors for tartaric acid.

In this study, crystal orientation and polymorphism formation in electrospun poly(vinylidene fluoride) (PVDF)/polyacrylonitrile (PAN) blend fibers after melt-recrystallization were studied. To achieve uniform alignment of electrospun fibers, mechanical stretching was applied to the as-spun nonwoven fibers at 110 °C. Pure ferroelectric β-PVDF crystals in the PAN matrix were achieved, and both polar β-PVDF and polar PAN crystals oriented with their chain axes parallel to the fiber axes. After melt-recrystallization of PVDF, a significant amount of ferroelectric β crystals was retained in addition to the formation of nonpolar α crystals. A polarized Fourier transform infrared study showed that the degree of orientation of ferroelectric β-PVDF crystals was higher than that of nonpolar α crystals, suggesting that the β-PVDF crystals should form at the PVDF/PAN interfaces because of strong dipolar and hydrogen bonding interactions between vinylidene fluoride and acrylonitrile units. The nonpolar α-PVDF crystals should form in the center of PVDF domains.

The photoelectrical properties of highly ordered TiO2 nanotube (TNT) arrays have been systematically and quantitatively studied and found to be closely related to their geometric and crystal structures. The geometric characteristics, including the nanotube diameter and length, were modified by adjusting the anodization potentials and durations, while the crystal structure was modified by thermal annealing at different temperatures. The nanotube array samples with the mixed crystalline phases possess higher photoconversion efficiency than those with the single anatase or rutile phase. The optimal content of rutile phase is about twice of that of anatase phase. In terms of the influence of the geometric structure, the TNT arrays with larger inner diameters and longer tube lengths have better photoelectrical properties. A geometric roughness factor has been applied to describe the combinative effect of the geometric characteristics. The TNT sample with the geometric roughness factor of 125.32 shows the superior photoconversion efficiency of 13.2%. The underlying mechanism has also been discussed in detail.

NaGd(WO4)2:Eu3+ nanotubes have been successfully synthesized by the hydrothermal method using carbon nanotubes (CNTs) as removable templates. X-ray diffraction, thermogravimetric and differential thermal analysis, transmission electron microscopy, and photoluminescence were used to characterize the product. It is demonstrated that CNTs are fully coated with an amorphous NaGd(WO4)2:Eu3+ layer, which is about 7 nm thick and almost continuous and uniform. After the NaGd(WO4)2:Eu3+/CNTs composites have been calcined at 500 or 600 °C, NaGd(WO4)2:Eu3+ nanotubes are obtained by removing the CNTs templates, and the outer diameter of that is about 40 nm. The luminescence properties of the NaGd(WO4)2:Eu3+ nanotubes calcined at various temperatures have been investigated. The results indicate that the products exhibit a characteristic red emission peak of Eu3+ ions at 615 nm. The emission intensity decreases with the increasing of annealing temperature, which is probably because a few residual carbons doped in NaGd(WO4)2:Eu3+ nanotubes and many oxygen vacancies could promote the intensity of red emission of Eu3+.

The Zr65Al7.5Ni10Cu17.5 bulk metallic glasses were prepared by injection casting (casting temperature of 1100 °C) and in situ suction casting (casting temperature as high as 3000 °C). The strain-rate-dependent mechanical behaviors of the specimens were investigated under axial compression at room temperature over a wide strain rate range (1.6 × 10−5–1.6 × 10−1 s−1). The specimens prepared by injection casting exhibited negative strain rate sensitivity, i.e., the yield stress decreased with increasing strain rate. In contrast, no strain rate sensitivity was observed for the specimens prepared by in situ suction casting. The different strain rate sensitivities in the specimens prepared at different temperatures were probably caused by the diversities of the local atomic structures.

Interrod regions exist between the enamel rods and are known to have different crystallite orientations and a higher organic content compared to the enamel rods (the intrarod regions). This study aims to characterize the mechanical properties of both regions especially the time-dependent properties by using spherical indentation. Despite the very small amount of proteins, the interrod region shows statistically significantly higher inelastic energy dissipation than the intrarod region with increased deformation times. The total displacement under constant load (creep), viscosity, and stress relaxation behavior of both regions are also reported. Similar to the observation of previous studies, the elastic modulus and hardness in the intrarod region are significantly higher than in the interrod region.

The preparation of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmImTFSI)-based poly(methyl methacrylate)–poly(vinyl chloride), PMMA–PVC, gel polymer electrolytes was done by solution casting technique. The ionic conductivity of gel polymer electrolytes was increased, up to a maximum value of (1.64 ± 0.01) × 10−4S/cm by adding 60 wt% of BmImTFSI. Conductivity–frequency dependence, dielectric relaxation, and dielectric moduli formalism were also further analyzed. These studies assert the ionic transportation mechanisms in the polymer matrix. Occurrence of polarization electrode–electrolyte interface is also observed. This leads to the formation of electrical double layer and hence indicates the non-Debye characteristic of the polymer matrix in the dielectric studies. Based on the changes in shift, changes in intensity, changes in shape, and existence of new peaks, attenuated total reflectance–Fourier transform infrared divulged the complexation between PMMA, PVC, lithium bis(trifluoromethanesulfonyl)imide, and BmImTFSI, as shown in the infrared spectra.

Chips produced by turning a commercial purity magnesium billet were cold compacted and then hot extruded at four different temperatures: 250, 300, 350, and 400 °C. Cast billets, of identical composition, were also extruded as reference material. Chip boundaries, visible even after 49:1 extrusion at 400 °C, were observed to suppress grain coarsening. Although 250 °C extruded chip-consolidated product showed early onset of yielding and lower ductility, fully dense material (extruded at 400 °C) had nearly 40% reduction in grain size with 22% higher yield strength and comparable ductility as that of the reference. The study highlights the role of densification and grain refinement on the compression behavior of chip consolidated specimens.

Nickel nanoparticles (NNPs) synthesized by a modified polyol method using ethylene glycol as a reducing agent, palladium chloride as a nucleating agent, and polyvinylpyrrolidone (PVP) as a protective agent were investigated as a potential magnetic adsorbent for the purification of hexahistidine-tagged (His6-tagged) recombinant proteins. The synthesis resulted in nanoparticles having an average diameter of 68 ± 28 nm. The x-ray diffraction pattern confirmed the presence of nickel metal, as well as the presence of unreacted nickel (II) hydroxide Ni(OH)2. Magnetic characterization showed that a magnetization saturation of 39.3 electromagnetic unit (emu)/g at 20,000 Oersted (Oe) was reached rapidly and that the material exhibited ferromagnetic behavior. Protein purification results showed that the synthesized NNPs were highly selective for binding to a His6-tagged recombinant protein single-domain antibody ToxA5.1. In addition, NNPs were used for four adsorption cycles without significant binding capacity losses. These particles have shown great potential such as being easily synthesized, cost-effective, and highly selective magnetic adsorbents for the purification of His6-tagged recombinant proteins.

The effect of the use of different zinc salts as zinc sources during hydrothermal growth of zinc oxide nanowires was systematically investigated. Change in the temperature, pH, and transmittance of the growth solutions prepared with three different zinc salts was monitored and used to provide a broad explanation to the effect of the salt. In addition to conventional heating process, microwave heating of the growth solutions was also performed, and differences in the ZnO nanowires synthesized through both heating methods were examined. It was found that ionization of zinc in growth solutions is influencing the formation of ZnO nanowires leading to growth with different aspect ratios, and zinc acetate dihydrate salt allows the synthesis of nanowires with the highest aspect ratio.

Normal spectral intensities of resistively heated preoxidized ZrB2–30 mol% SiC–6 mol% B4C specimens were measured in the 1–6 μm and ∼1100–1500 °C ranges. Using Wein’s displacement law, the temperatures of these specimens were determined, in turn permitting calculation of normal spectral emittances using Planck’s law. Spectral emittance data were affected by absorption/emission of H2O/CO2 gases; total emittances were determined from the averages of data in spectral ranges devoid of gaseous interference. Total emittances decreased from 1.0 at 1100 °C to 0.8 at 1500 °C. This trend is consistent with the behavior expected of a dielectric coating.

Intense broad absorption bands centered around 1.7, 2.5, 3.1, and 3.7 eV take place in Er3+-diffused layer formed near MgO (5 mol%)-doped LiNbO3 crystal surface by in-diffusion of Er metal under Li-poor atmosphere. These bands are tentatively attributed to the defect absorption of small polarons, bipolarons, F-centers, and Q-polarons created due to Er3+ in-diffusion and Li2O loss from the crystal. It is interesting that the number, type, area, and peaking position of the bands can be controlled by the diffusion temperature and further oxidation treatment. Such material is a promising medium for data storage based upon two-color holography.

Resistive memory devices have the potential to replace flash technology due to their increased scalability, low voltage of operation, and compatibility with silicon semiconductor manufacturing. We report a spin-on resistive switching material, hydrogen silsesquioxane (HSQ), which is a commonly used electron beam resist. We demonstrate device scalability from 100 μm to 48 nm and show that the switching properties do not depend on the device size. Set voltages were typically <3 V, while reset voltages were <1 V when analyzing the positive unipolar switching properties of these devices. The ratio of the high resistance to the low resistance was ranged from 101 to 102, creating a distinct memory window between the memory states. Composition–depth profiling revealed that copper from the bottom electrode migrated into the HSQ films as a result of annealing. It is therefore speculated that copper may play a role in the switching properties of devices based on this material.

The thermoelectric parameters have been investigated depending on the thickness of the layer of nanostructures IV–VI (PbS, PbSe, PbTe, and SnTe). Based on the theoretical model of quantum well (QW) with infinitely high walls, it is demonstrated that this model explains nonmonotonous behavior of the Seebeck coefficient S with the change of the well width. On the basis of oscillation period Δdexp, we have approached the theoretical d-dependence of the coefficient S to the experimental one and defined the value of the Fermi energy in the corresponding nanostructures. It has been established that the minimum QW width dmin, where the first energy level coincides with the Fermi energy, is equal to the oscillation period of the Seebeck coefficient in this structure.

The transport properties of doped and undoped, high quality, plasma-assisted molecular beam epitaxy grown tin dioxide (SnO2) thin films are reviewed. Intentional doping can vary the SnO2 resistivity over more than seven orders of magnitude from a transparent conducting oxide-like conductivity up to the semi-insulating range. A region of high unintentional n-type conductivity was identified in the substrate interface region and had to be accounted for. Sb was a well-behaved shallow donor up to the regime of conducting oxides. In and Ga were too deep acceptors to achieve p-type conductivity but were suitable to render SnO2 semi-insulating. While the surface accumulation layer strongly influenced contact properties, its conductance was negligible. The methodology used here for studying the transport can also be applied to other semiconducting oxides.