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Surface modification has been used as a method to create defects on ${\mathrm{\text{TiO}}}_2$ materials, which can improve their desirable properties. In this paper, defected ${\mathrm{\text{TiO}}}_2$ nano-powder was successfully synthesized by chemical reduction using ${\mathrm{\text{NaBH}}}_4$ as the reducing agent at 300–400${}^{\circ }\mathrm{\text{C}}$ under argon atmosphere. High defect concentration can be produced by increasing process temperature. The modified ${\mathrm{\text{TiO}}}_2$ shows good visible light absorption and photocatalytic activity on degradation of Rhodamine B (4–9 times higher than the pristine ${\mathrm{\text{TiO}}}_2$) with the visible light irradiation. Further XPS analysis and theoretical studies using full potential linearized augmented plane wave (FP-LAPW) method as implemented in wien2k code revealed the existence of oxygen vacancy and ${\mathrm{\text{Ti}}}^{3+}$ in the modified samples. These types of defects were responsible for the modifications of the electronic and optical properties of ${\mathrm{\text{TiO}}}_2$, resulting in the improved photocatalytic activity in visible light irradiation.

In this paper, we theoretically investigate the transmittance characteristics of one-dimensional defective photonic crystal in microwave radiations based on the fundamentals of the characteristic matrix method. Here, the defect layer is magnetized plasma. The numerical results show the appearance of defect peaks inside the Photonic Band Gap. The external magnetic field has a significant effect on the permittivity of the defect layer. Therefore, the position and intensity of the defect peak are strongly affected by the external magnetic field. Moreover, we have investigated the different parameters on the defect peaks as the plasma density, the thickness of the plasma layer and the angle of incidence. Wherefore, the proposed structure could be the cornerstone for many applications in microwave regions such as narrowband filters.

In the present study, the defect was introduced in the form of missing strut for the individual cell. The effect of defect on the compressive response of carbon-fiber pyramidal truss cores sandwich panel was investigated through experimental and theoretical methods. A series of sandwich panel sample with or without defect was fabricated, and compressive tests were performed at ambient temperature. Scanning electron microscopy (SEM) was conducted on the samples to evaluate the carbon-fiber distribution and failure mode. A revised theoretical model was proposed to predict the effect of defect considering the strut bending and shear behavior. Our results revealed that the compressive moduli of sandwich panel decrease linearly with the fraction of missing struts. Comparing with open-cell foams and honeycombs, the pyramidal truss has better defect tolerance. The theoretical result calculated by the proposed model was in general agreement with experimental result.

Composite stiffened-structure consists of the skin and stringer has been widely used in aircraft fuselage and wings. The main purpose of the article is to detect the composite material reinforced structure accurately and explore the relationship between defect formation and structural elements or curing process. Based on ultrasonic phased array inspection technology, the regularity of defects in the manufacture of composite materials are obtained, the correlation model between actual defects and nondestructive testing are established. The article find that the forming quality of deltoid area in T-stiffened structure is obviously improved by pre-curing, the defects of hat-stiffened structure are affected by the mandrel. The results show that the ultrasonic phased array inspection technology can be an effectively way for the detection of composite stiffened-structures, which become an important means to control the defects of composite and improve the quality of the product.

Oxygen-deficient zinc oxides thin films with different levels of defects were prepared by using radio frequency magnetron sputtering method with sintered zinc oxide disk as target at different sputtering powers. The composition, structure and electrical properties of the prepared films were investigated. Under the present conditions, all the obtained films possessed würtzite structure, which were growing preferentially along the $c$-axis. The thickness of the films, the size of the zinc oxide grains and the content of Zn atoms increased with increasing sputtering power. In the films deposited at a sputtering power from 52W to 212W, the main defect was interstitial zinc. With increasing sputtering power, due to the enhanced number of interstitial zinc in the films, their room-temperature electrical resistivity would decrease, which was controlled by electron conduction. At increasing measurement temperature, their electrical resistivity would increase, owing to the decrease of defect concentration caused by oxidization.

Knee joint is the hub of human lower limb movement and it is also an important weight-bearing joint, which has the characteristics of load-bearing and heavy physical activities. So the knee joint becomes the predilection site of clinical disease. Once people have the cartilage lesions, their daily life will be affected seriously. The simulation of the knee joint lesions could provide help for clinical knee-joint treatment. Based on the complete model of knee joint, this paper use the finite element method to analyze the biomechanical characteristics of the defective knee joint. The results of simulation show that the stress of cartilages when standing on single leg is approximately doubled than that of standing on two legs. When standing on single leg, the 8-mm diameter osteochondral defect in femur cartilage can generate maximal changes in von-mises stress (by 36.74%), while the von-mises stress on tibia cartilage with 8-mm defect increase by 87%. The stress distribution of cartilages is almost the same, there is no obvious stress concentration when in defect. Increasing the defective diameter, femoral cartilage, meniscus and tibial all present an increasing trend towards stress. When increasing the applied load, the stress of the femoral cartilage, the meniscus and the tibial cartilage all increased.

In this paper, in order to effectively utilize salt lake magnesium resources, we focused on a functional material containing magnesium, i.e. magnesium oxide, MgO, which is a type of antibacterial material. Through a first-principles study from the atomic level, the microstructure of MgO containing doped point defects of different elements was studied. The relationship between the microscopic structure of the material and its special antibacterial function was explored. The results are as following: the interstitial impurities in MgO are more helpful than substituted impurities for the improvement of the electronic structure. The analysis of the influence of different doping elements on the microstructure confirmed theoretically that Ag and Cu have the same highly active antimicrobial properties with the same change of microstructure, thereby confirming the relationship between microstructure and antimicrobial activity. The results of the simulations match the experimental results, thereby theoretically demonstrating the relationship between defects and antibacterial activities and providing further insight into the nature of the antibacterial mechanism.

Based on the molecular dynamics (MD) method, the single-crystalline copper nanowire with different surface defects is investigated through tension simulation. For comparison, the MD tension simulations of perfect nanowire are first carried out under different temperatures, strain rates, and sizes. It has concluded that the surface–volume ratio significantly affects the mechanical properties of nanowire. The surface defects on nanowires are then systematically studied in considering different defect orientation and distribution. It is found that the Young's modulus is the insensitive of surface defects. However, the yield strength and yield point show a significant decrease due to the different defects. Different defects are observed to serve as a dislocation source.

In this paper, we give formulas for the Hodge numbers of a nodal complete intersection in a complex projective space. We apply these formulas to construct examples of Calabi–Yau threefolds with $h^{1,1}=2$.

In the present work, we report the blue phase (BP) in a binary mixture of cholesteryl nonanoate (CN) and N-(4-ethoxybenzylidene)-4-butylaniline (EBBA). The mixture exhibits BP over a temperature range of 2.3 K at optimum composition (50:50) of liquid crystals (LCs). The effect of silica nanoparticles (SNPs) doping on thermal stability of BPs has also been demonstrated and nearly 6 K wide BP temperature range was achieved at 0.5 wt.% of SNPs. A porous type texture was also observed during the BP formation process in the doped samples.

The influence of Nb₂O₅-doped concentration on the positive temperature coefficient of resistance (PTCR) effect, electrical properties and microdefects of (Ba${}_{0.95}$Sr${}_{0.05}$)(TiNb${}_x$)O₃ (BSTN) ceramics were investigated. Firing was conducted at 1350${}^{\circ }$C for 2 h in air. The donor-doped content affected the electrical properties, PTCR effect and formation of the microdefect type of the BSTN samples. The room temperature resistivity of the BSTN specimens first decreased and then increased with increasing donor-doped content in the range of 0.2 mol.% Nb${}^{5+}$ to 0.5 mol.% Nb${}^{5+}$. Moreover, the information on microdefects in BSTN ceramics was demonstrated by coincidence Doppler broadening spectrum. The influence of the defects on the PTCR characteristics of the ceramics was also revealed.

The electronic behavior of semiconducting carbon nanotubes based CNTFET under the influence of radial deformation defect present in the channel is theoretically investigated using nonequilibrium Green's function method self-consistently coupled with three-dimensional electrostatics. It was found that deformation in the CNTFET channel composed of a small diameter semiconducting carbon nanotube can increase its conductance by a factor of 4 or more depending upon the average reduction in the C–C bond length after compression. This increase in CNTFET conductance is directly related to the movement of the electronic states toward the Fermi level when the tubes are squeezed. Furthermore, the device ON–OFF current ratio also decreases with increase in applied compression which makes it hard to switch-OFF the device.

Oxygen-deficient tin oxide thin films were prepared by radiofrequency magnetron sputtering with a sintered non-stoichiometric tin oxide ceramic target under an atmosphere of various ratios of O₂/Ar from pure Ar to 1:1. X-ray diffraction analysis showed that the thin films were polycrystalline with relatively strong (1 1 0), (1 0 1) and (2 1 1) diffraction peaks. Scanning electron microscopy observation revealed that the thin films prepared at different O₂/Ar ratios were all of relatively dense and homogeneous structure. With increasing O₂/Ar ratio, the grain size of the films decreased slightly, and their chemical composition became close to the stoichiometric SnO₂; but the deposition rate as well as film thickness increased first and then decreased sharply. It was revealed that the main defect in obtained films was oxygen vacancy (V_O), and as the O₂/Ar ratio increased, the concentration of V_O fell down monotonously, which would lead to an increased electrical resistivity.

Direct growth of large-area uniform graphene films on insulating materials could facilitate the applications of graphene in optoelectronic devices. The ultrafast photocarrier relaxation and saturable absorption of direct chemical vapor deposition-grown graphene glasses, with lots of defects, are studied by using femtosecond time-resolved pump–probe and Z-scan techniques at 800 nm. We find that both the relaxation times associated with hot carrier cooling and the hot phonon effect are greatly suppressed in these defect-rich graphene glasses, which further leads to the increase of both saturation intensity and anisotropy in transient optical response for graphene glasses as compared with defect-free graphene. And, both the suppression effect and saturation intensity increase with the thickness of graphene film. The dominance of defect-assisted carrier-acoustic phonon scattering (i.e., supercollision, the collision of a carrier with both an acoustic phonon and defects) in the cooling process of hot carriers is responsible for the suppression of relaxation time.

We prove that a valued field of positive characteristic $p$ that has only finitely many distinct Artin–Schreier extensions (which is a property of infinite NTP₂ fields) is dense in its perfect hull. As a consequence, it is a deeply ramified field and has $p$-divisible value group and perfect residue field. Further, we prove a partial analogue for valued fields of mixed characteristic and observe an open problem about 1-units in this setting. Finally, we fill a gap that occurred in a proof in an earlier paper in which we first introduced a classification of Artin–Schreier defect extensions.

Effects of non-cleaning and cleaning fluxes on wetting properties and defects at flow-soldered joints were investigated. RMA-type flux of 15% solid content was used for cleaning flux, and R-type flux of 3.3% solid content for non-cleaning flux. A wetting test was conducted by the wetting balance method using a vertical flat Cu plate with various surface conditions: polished, non-polished, plated with Sn-37%Pb and oxidized. Sn-37%Pb eutectic alloy was used as solder. A flow soldering process was performed using both type of fluxes, and a visual inspection was carried out after soldering process. As experimental results reveal, wetting times of polished and Sn-37%Pb plated specimens were shorter than those of non-polished and oxidized specimens. Wetting time for using non-cleaning flux was short enough to be considered as having good wettability. Conveyor speed of printed circuit board (PCB) had great effects on the icicle and bridge defect regardless of flux-type. Conveyor speed of 1 m/min was optimum speed for cleaning flux, and in the case of the non-cleaning flux, 1–2 m/min was acceptable and preheating temperature affects the joint defect relatively less.

The molybdenum-doped ZnO (MZO) films were deposited on quartz substrates by radio frequency magnetron sputtering. All films have a polycrystalline hexagonal wurtzite structure. Mo doping influences the grain size of the MZO films and leads to a compressive stress in the films. The valence of Mo in the MZO films is hexavalence. Mo doping enhances the emissions at 380 and 412 nm. Annealing significantly influences the photoluminescence (PL) spectra of the MZO films. The PL spectral intensity of the annealed films is much higher than that of the unannealed films. The emissions at 400 and 525 nm enhanced dramatically with the rising of annealing temperature while the emissions at 380 and 412 nm became weak or disappeared. Mo doping is beneficial for the enhancement of the emissions at 400 and 525 nm of the annealed MZO films. The origins of these emissions were discussed in detail.

The forming defects occurred during each forming processes of poly-wedge pulley spinning, such as the drumming failure, flanged opening-end, folded side-wall, insufficient bottom size, flashed opening-end, cutting-off bottom, are introduced, and the factors influencing the defects are analyzed. The corresponding preventive measures are put forward, which establishes a reliable base for practical manufacture and theoretical research of poly-wedge pulley spinning.