The Microstructures and Characteristics of NiO Films: Effects of Substrate Temperature.

The influence of the substrate temperature on the structural, surface morphological, optical and nanomechanical properties of NiO films deposited on glass substrates using radio-frequency magnetron sputtering was examined by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Visible spectroscopy and nanoindentation, respectively. The results indicate that the substrate temperature exhibits significant influences on both the grain texturing orientation and surface morphology of the films. Namely, the dominant crystallographic orientation of the films switches from (111) to (200) accompanied by progressively roughening of the surface when the substrate temperature is increased from 300 °C to 500 °C. The average transmittance of the NiO films was also found to vary in the range of 60-85% in the visible wavelength region, depending on the substrate temperature and wavelength. In addition, the optical band gap calculated from the Tauc plot showed an increasing trend from 3.18 eV to 3.56 eV with increasing substrate temperature. Both the hardness and Young's modulus of NiO films were obtained by means of the nanoindentation continuous contact stiffness measurements mode. Moreover, the contact angle between the water droplet and film surface also indicated an intimate correlation between the surface energy, hence the wettability, of the film and substrate temperature.

Investigation of the Defect Structure of Congruent and Fe-Doped LiNbO3 Powders Synthesized by the Combustion Method.

Fe-doped LiNbO3 synthesized by the combustion method to seek new multiferroic materials exhibits room-temperature ferromagnetism, as reported in our previous work [1]. In this work, the defect structure of congruent and Fe-doped LiNbO3 (0.57-3.3 mol %) powders was investigated in detail by several methods. The molar ratio of [Li]/([Li]+[Nb]) was determined by the Curie temperature (Tc) via DSC. Two peaks of Tc were observed due to phase splitting [2], and the phase at lower Tc disappears as the Fe doping concentration increases. The coexistence of two different oxidation states of Fe ions in LiNbO3 was probed by XPS and UV-Vis spectroscopy. The Raman spectra exhibit displacements along the c axis of Li and Nb ions, and a deformation of the NbO6 framework owing to Fe doping. Several doping models were applied in the Rietveld refinement of powder X-ray diffraction collected by synchrotron radiation. The fitting by the Nb vacancy model leads to an improbably distorted structure of congruent LiNbO3. In Fe-doped LiNbO3, we conjecture that Li and Nb vacancies coexist in the lattice structure; Fe+2/Fe+3 ions are substituted for Li ions at the regular Li site and may push the anti-site NbLi ion back to the regular Nb site.

Mechanical Properties of Cu2O Thin Films by Nanoindentation.

In this study, the structural and nanomechanical properties of Cu2O thin films are investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and nanoindentation techniques. The Cu2O thin films are deposited on the glass substrates with the various growth temperatures of 150, 250 and 350 °C by using radio frequency magnetron sputtering. The XRD results show that Cu2O thin films are predominant (111)-oriented, indicating a well ordered microstructure. In addition, the hardness and Young's modulus of Cu2O thin films are measured by using a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) option. Results indicated that the hardness and Young's modulus of Cu2O thin films decreased as the growth temperature increased from 150 to 350 °C. Furthermore, the relationship between the hardness and films grain size appears to closely follow the Hall-Petch equation.

Characterization of a new male sterility-related gene Camf1 in Capsicum annum L.

For the sake of screening novel genes related to the male sterility in chili pepper for studying the molecular mechanism of plant male sterility, the gene differential expression analysis was performed by cDNA-amplified fragment length polymorphism (cDNA-AFLP) in the genic male sterile-fertile line 114AB of Capsicum annum L., and a variety of differentially expressed cDNA fragments were detected in fertile or sterility material. Camf1, a transcript-derived fragment (TDF) accumulated in fertile line flower buds was further investigated. The Camf1 has 1,854 bp in length with no introns containing a 1,707-bp open reading frame (ORF). The deduced amino acid sequence of Camf1 shares higher similarity to some members from a glyoxal oxidase-related protein family, and has a glyoxal oxidase conserved domain at the N-terminus and a domain of unknown function (DUF1929) at C-terminal end. Expression analysis showed that Camf1 expressed only in stage 3-7 flower buds of male fertile of C. annum L. 114AB, and no detection in all organs of male sterility. The peak of expression level of Camf1 appeared at stage 4 flower buds of fertile line. Furthermore, expression analysis of different organs revealed that Camf1 expressed only in anthers of male fertile material and there were no expression in sepals, petals, pistils, roots, stems, leaves and open flowers. These results suggested that Camf1 was an anther-specific gene and might be essential for the fertility of C. annum L.

Berkovich Nanoindentation on AlN Thin Films.

Berkovich nanoindentation-induced mechanical deformation mechanisms of AlN thin films have been investigated by using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM) techniques. AlN thin films are deposited on the metal-organic chemical-vapor deposition (MOCVD) derived Si-doped (2 × 1017 cm-3) GaN template by using the helicon sputtering system. The XTEM samples were prepared by means of focused ion beam (FIB) milling to accurately position the cross-section of the nanoindented area. The hardness and Young's modulus of AlN thin films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) option. The obtained values of the hardness and Young's modulus are 22 and 332 GPa, respectively. The XTEM images taken in the vicinity regions just underneath the indenter tip revealed that the multiple "pop-ins" observed in the load-displacement curve during loading are due primarily to the activities of dislocation nucleation and propagation. The absence of discontinuities in the unloading segments of load-displacement curve suggests that no pressure-induced phase transition was involved. Results obtained in this study may also have technological implications for estimating possible mechanical damages induced by the fabrication processes of making the AlN-based devices.

[Application of kanamycin in transgenic mustard(Brassica juncea Coss.)].

In order to find the best screening kanamycin concentration in the genetic transformation of mustard (Brassica juncea Coss.), the seedling cotyledons of mustard were placed on bud-induced media supplemented with different kanamycin concentrations. The bud differentiation of explants was totally inhibited when the kanamycin concentration was greater than 30 mg/L. The seeds of mustard were placed on germination media supplemented with different concentrations of kanamycin. All the seedlings were white when kanamycin concentration was higher than 200 mg/L. The leaves of mustard in field were smeared with the solutions including different concentrations of kanamycin. The treated leaves showed white when kanamycin concentration was over 200 mg/L. To study the segregation of the alien gene in transgenic mustard offspring, the transgenic mustard seeds and the leaves of the transgenic mustard offspring using npt-gene as assistant selection-marker were treated with 200 mg/L kanamycin, and the results were analyzed by chi-square test. The segregation ratio in the offspring of 4 transgenic lines with single copy of transgene agreed with a ratio of 3:1. The segregation ratio in offspring of the one transgenic line with double copies was agreed with a ratio of 3:1, and the segregation ratio in offspring of the other transgenic line with double copies was agreed with ratios of 3:1 and 15:1 simultaneously. It is indispensable to thoroughly study the insert of the double copies of transgenes in transgenic mustard. PCR technology was used to confirm the above detection methods. It is concluded that applying kanamycin to screen transgenic mustard offspring is feasible.