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We have studied microwave photoresistance in a two-dimensional electron system subject to two radiation fields (frequencies ω1 and ω2) using quantum kinetic equation. We have found that when ω2/ω1 = 1 + 2/N, where N is an integer, and both waves have the same polarization, the displacement mechanism gives rise to a new, phase-sensitive photoresistance. This photoresistance oscillates with the magnetic field and can be a good fraction of the total photoresistance under typical experimental conditions. The inelastic mechanism, on the other hand, gives zero phase-sensitive photoresistance if the radiation fields are circularly polarized. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of Sb2O3 nano-particles by vapor transport and condensation of metallic antimony in oxidizing environment. Granular antimony inside an alumina crucible is placed in the middle of a tube furnace at 550 °C with air flow rate of 400 mL/min. Al foil, glass and Si-wafer, which are used as substrates, are placed downstream of the gas flow at a temperature of about 250 °C for the deposition of antimony oxide. The deposited antimony oxides on the substrates and the oxidized granular antimony in the alumina crucible are examined with field emission scanning electron microscopy, X-ray diffractometer and transmission electron microscopy (TEM). The deposited antimony oxide consists of Sb2O3 nano-particles, while the oxidized granular antimony in the crucible consists of SbO2. The mechanism of the formation of Sb2O3 nano-particles is analyzed based on oxidation reaction thermodynamics and kinetics. [ABSTRACT FROM AUTHOR]

Understanding the elusive catalytic role of titanium-based additives on the reversible hydrogenation of complex hydrides is an essential step toward developing hydrogen storage materials for the transport sector. Improved bulk diffusion of hydrogen is one of the proposed effects of doping sodium alanate with TiCl3, and here we study hydrogen dynamics in doped and undoped Na3AlH6using a combination of density functional theory calculations and quasielastic neutron scattering. The hydrogen dynamics is found to be vacancy mediated and dominated by localized jump events, whereas long-range bulk diffusion requires significant activation. The fraction of mobile hydrogen is found to be small for both undoped and doped Na3AlH6, even at 350 K, and improved hydrogen diffusion as a result of bulk-substituted titanium is found to be unlikely. We also propose that previously detected low-temperature point defect motion in sodium alanate could result from vacancy-mediated sodium diffusion. [ABSTRACT FROM AUTHOR]

Helium-containing titanium film was prepared by magnetron sputtering in a gas mixture of helium and argon. This method distinctly differs from traditional helium introduction into metals. A high concentration of helium up to 45?at.% and a uniform distribution in the bulk were shown by ion beam analysis. The process of helium incorporation is considered in which the helium particles are energetically backscattered from the target, fly through the glow discharge zone and are consequently embedded into the growing film. It is virtually a continuous sub-threshold-energy implantation during film deposition based on the plasma technique. The limited partial pressure of argon is to maintain the discharge and sputter the titanium target. The helium content incorporated can be controlled conveniently by adjusting the pressure of the working gases. X-ray diffraction, transmission electron microscopy, Doppler broadening of positron beam analysis and thermal helium desorption spectroscopy revealed the microstructure of titanium films, the state of helium bubbles, the defect characteristic related to helium and thermal release behaviour of helium from the titanium film. [ABSTRACT FROM AUTHOR]

We report first-principles calculations on the electrical transport properties of two kinds of one-dimensional nanowires:  (a) a carbon nanowire (CNW) with alternating single and triple bonds and (b) a boron−nitrogen nanowire (BNNW) with equidistant bonds. We demonstrate the similarity and difference between the carbon nanowire and its boron−nitrogen analogue in the molecular orbital and transport properties, and then explore the potential innovations. The effects of molecular orbitals and nanowire-electrode coupling on the transport properties are analyzed. The cases of the nanowires sandwiched between both nanoscale and bulk electrodes are considered. It suggests that the characteristics of the transmission spectra and the current−voltage characteristics (I−Vcurves) are determined both by the electrodes and by the molecule as well as their coupling. In particular, the negative differential resistance (NDR) phenomenon is more apparent when the nanowires are positioned between two nanoscale electrodes. The tuning of the transport properties is also probed through the changes of nanowire−electrode separation and the inclusion of a gate voltage. These lead to dramatic variations in the equilibrium conductance, which can be understood from the shift and alignment of the molecular orbital relative to the Fermi level of the electrodes. In the analysis of the effects of nanowire−electrode separation, it shows that the equilibrium conductance has the same variation behavior as that of the projected density of states (PDOS) for CNW, while the localized molecular orbitals of BNNW result in its conductance varies differently from its PDOS. The different molecular orbital characteristics near the Fermi level of these two kinds of nanowires underlie their different transport properties. [ABSTRACT FROM AUTHOR]

Using a bond order potential, molecular dynamics simulations have been performed to study the mechanical properties of ultrathin single-walled carbon nanotubes with or without junction under uniaxial tensile loading. The (3, 3) armchair and (5, 0) zigzag nanotubes have been studied. Topological defects in the junction region influence the mechanical properties of junctions. [ABSTRACT FROM AUTHOR]

The hemicellulose content of cellulosic material from poplar chemithermomechanical pulp (CTMP) was controlled by a microwave-assisted formic acid (MFA) extraction process. The environmentally friendly, selfbonded, and cellulose-rich fiber sheets (around 0.3 mm thick and 280 g/m2 grammage) were fabricated via a molding and compression process. The results showed that the MFA treatment effectively controlled the hemicellulose content in the range from 6.8% to 20.4%. Mechanical testing results showed a good linear relationship between the tensile strength and the hemicellulose content, where a higher hemicellulose content obtained a stronger tensile strength. Meanwhile, as hemicellulose content decreased, the onset temperature, representing the thermal stability, increased from 318.1 °C to 335.7 °C and the elastic modulus, representing the mechanical stiffness, increased from 0.047 MPa to 0.068 MPa. Additionally, as the hemicellulose content decreased, the water-resistance of the cellulose-rich fiber sheets improved. During the hemicellulose removal process, the strength of single fibers was found to have a dominant role in the mechanical strength of the cellulose-rich fiber sheets, rather than the inter-fiber bonding strength. This was contrary to research on the delignification process, where the inter-fiber bonding strength was found to be more important than the strength of single fibers in deciding the material strength. [ABSTRACT FROM AUTHOR]

Presents the results of a study on 2,2′-(1,2-Ethanediyldithio)bis(1,3-benzothiazole).

Current oscillation will occur when a piezoelectric ceramic vibrator is driven by a high electric field. The mechanism of cur- rent oscillation is discussed, based on the results of the present experiment. Ring-shaped lead zirconate titanate (PZT) piezo-electric vibrators are driven by a 5.65 V electric held with a fixed frequency of slightly less than resonance, to form an oscillating current. The sample current, temperature, and phase between the driven electric field and sample current are recorded. The resonance frequency of PZT rings shifts in the direction of low frequency under a high electric field due to the heat produced by dissipated power. and then shifts hack due to the effects of aging, which results In current oscillation. The oscillation phenomenon is explained according to the production of strong internal stresses due to abrupt change in temperature, and then, aging process through the rearrangement of domains to relieve various stresses. [ABSTRACT FROM AUTHOR]

First-principles calculations are performed to inspect the electronic and transport properties of a Fe-thiacrown molecular device, namely, a Au-Fe(9S3)2-Au junction. It is found that the junction has a low-spin (LS) ground state and a high-spin (HS) metastable state. Further study shows that the HS state is a conducting state while the LS state is a nearly insulating one, which means that a switch between these two spin configurations results in a good electrical switching behavior and can serve as an ON/OFF state for a logic unit. Thus, it may find applications as switches or memories in molecular electronic circuits. [ABSTRACT FROM AUTHOR]

Ipomoeassin F, the flagship congener of a resin glycoside family exhibited single-digit nanomolar IC50 values against several cancer cell lines. To facilitate drug discovery based on this unique yet underexplored natural product, we performed the most sophisticated SAR studies of ipomoeassin F to date, which not only greatly bettered our understanding of its pharmacophore but also led to the discovery of two new derivatives 2 and 3 with similar potency but improved synthetic profile. The work presented here opens new avenues toward harnessing the medicinal potential of the ipomoeassin family of glycolipids in the future. [ABSTRACT FROM AUTHOR]

Kenaf fiber-polyester composites incorporated with powdered activated carbon (PAC) were prepared using the vacuum-assisted resin transfer molding (VARTM) process. The product demonstrates the electromagnetic interference (EMI) shielding function. The kenaf fibers were retted in a pressured reactor to remove the lignin and extractives in the fiber. The PAC was loaded into the freshly retted fibers in water. The PAC loading effectiveness was determined using the Brunauer-Emmett-Teller (BET) specific surface area analysis. A higher BET value was obtained with a higher PAC loading. The transmission energies of the composites were measured by exposing the samples to the irradiation of electromagnetic waves with a variable frequency from 8 GHz to 12 GHz. As the PAC content increased from 0% to 10.0%, 20.5% and 28.9%, the EMI shielding effectiveness increased from 41.4% to 76.0%, 87.9% and 93.0%, respectively. Additionally, the EMI absorption increased from 21.2% to 31.7%, 44.7% and 64.0%, respectively. The ratio of EMI absorption/shielding of the composite at 28.9% of PAC loading was increased significantly by 37.1% as compared with the control sample. It was indicated that the incorporation of PAC into the composites was very effective for absorbing electromagnetic waves, which resulted in a decrease in secondary electromagnetic pollution. [ABSTRACT FROM AUTHOR]

The A-type lamin deficient mouse line (Lmna-/-) has become one of the most frequently used models for providing insights into many different aspects of A-type lamin function. To elucidate the function of Lmna in the growth and metabolism of mice, tissue growth and blood biochemistry were monitored in Lmna-deficient mice, heterozygous (Lmna+/-) and wide-type (Lmna+/+) backcrossed to C57BL/6 background. At 4 weeks after birth, the weight of various organs of the Lmna-/-, Lmna+/- and Lmna+/+ mice was measured. A panel of biochemical analyses consisting of 15 serological tests was examined. The results showed that Lmna deficient mice had significantly decreased body weight and increased the ratio of organ to body weight in most of tissues. Compared with Lmna+/+ and Lmna+/- mice, Lmna-/- mice exhibited lower levels of ALP (alkaline phosphatase), Chol (cholesterol), CR (creatinine), GLU (glucose), HDL (high-density lipoprotein cholesterol) and higher levels of ALT (alanine aminotransferase) (p<0.05). Lmna-/- mice displayed higher AST (aspartate aminotransferase) values and lower LDL (lowdensity lipoprotein cholesterol), CK-MB (creatine kinase-MB) levels than Lmna+/+ mice (p<0.05). There were no significant differences among the three groups of mice with respect to BUN (blood urea nitrogen), CK (creatine kinase), Cyc C (cystatin C), TP (total protein), TG (triacylglycerols) and UA (uric acid) levels (p>0.05). These changes of serological parameters may provide an experimental basis for the elucidation of Lmna gene functions. [ABSTRACT FROM AUTHOR]

The article presents a study which aims to examine the efficacy of Dapsone as the treatment drug for the dapsone hypersensitivity syndrome. It states that a genomewide association study including 872 participants who had medicated with dapsone as part of multidrug therapy for leprosy was executed through the use of log-additive tests of single-nucleotide polymorphisms (SNPs) and HLA molecules. Results show that there is a connection between SNPs and the dapsone hypersensitivity syndrome.

The objective of this study was to investigate the deformation behavior and damage model of bamboo bundle corrugated laminated composites under low velocity impact loading. The influence of different stacking sequences, i.e., bamboo bundle parallel to the corrugated waves (type I), cross-ply (type II), and perpendicular to the waves (type III), in laminates was studied in regard to impact loading. A shape parameter, K, was developed to quantify the effect of corrugation on impact response. The results of this study indicated that the type I composites displayed the optimum impact performance, followed by types II and III. The total energy absorbed by the type I laminates was 1.3 and 2.2 times as much as types II and III. The values of peak load were type I > type II > type III. The composites deformed and failed in different manners under low velocity impact loading: material failure, delamination and fiber tensile fracture, and structural collapse were the main modes of failure for type I, II, and III, respectively. The effect of the corrugated shape on impact properties of composites was positive for type I, but negative for type II composites. [ABSTRACT FROM AUTHOR]

Abstract  A new 3D layered compound, [Pb2(L)2H2O] n (L is phenylmalonic acid) was hydrothermally synthesized and characterized by single-crystal X-ray diffraction. In the compound, lead has four coordination modes. The compound has formed a 2D surface shape structure through these coordinate modes with the ligand, and this 2D layer piles through C-H...π forms the 3D compound. [ABSTRACT FROM AUTHOR]

Abstract  A novel Cu(II) complex Cu2(Endc)2(Bipy)2 has been synthesized by the reaction of Cu(NO3)2 · 3H2O, Endc (endo-norbornene-cis-5,6-dicarboxylic acid), and Bipy (2,2-bipyridine) at room temperature. Elemental analysis, IR spectra, and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure. Crystal data for this complex: triclinic, P $$ \bar 1 $$ with a = 9.0373(10), b = 10.1637(11), c = 10.5574(12) Å, α = 65.78(1)°, β = 72.32(2)°, β = 73.23(2)°, Z = 1, V = 827.46(16) Å3, ρ c = 2.160 g/cm3, F(000) = 410.0, R = 0.0483 and wR = 0.0958 independent reflections for 4468 observed ones (I > 2 σ(I)).The Cu2+ ion is coordinated by two nitrogen atoms from the Bipy molecule and three oxygen atoms from two Endc, giving a distorted squarepyramidal coordination geometry. Two neighboring Cu2+ ions are bridged by a pair of bimonodentate carboxyl groups of different Endc acids, giving a centrosymmetrical binuclear structure which a Cu…Cu distance of 3.2946 Å. The photoluminescence properties of the complex were studied at room temperature. The complex displays an obvious photoluminescent emission upon excitation at 390 nm in the solid state. [ABSTRACT FROM AUTHOR]

Abstract  Five copper complexes with 4,5-diazafluoren-9-one have been reported. Some of their structures are determined by single crystal X-ray diffraction. On the basis of experimentation, all the complexes were calculated by DFT-B3LYP/LANL2DZ in Gaussian-98w. By analyzing the experimental and calculated values, it can be concluded, on the one hand, that the experimental results are proved thoroughly by the theoretical calculated results; on the other hand, the theoretical calculated results can deduce the experimental results reasonably well. [ABSTRACT FROM AUTHOR]

We studied the effects of sintering temperature on the phase transformation, lattice parameters, full width at half-maximum (FWHM), strain, critical temperature (Tc), critical current density (Jc) and resistivity (?) in MgB2/Fe wires. All samples were fabricated by the in situpowder-in-tube method (PIT) and sintered within a temperature range of 650-900?°C. It was observed that wires sintered at low temperature, 650?°C, resulted in higher Jcup to 12 T and lower Tc. The best transport Jcvalue reached 4200 A cm?2at 4.2 K and 10 T. This is related to the grain boundary pinning due to small grain size. On the other hand, wires sintered at 900?°C had a lower Jcin combination with a higher Tc. [ABSTRACT FROM AUTHOR]

Abstract  Thirteen solid ternary complexes Ln(Pdc)3(Phen) (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu;) have been synthesized in absolute ethanol by rare-earth element chloride low hydrate reacting with the mixed ligands of ammonium pyrrolidinedithiocarbamate (APdc) and 1,10-phenanthroline H2O (o-Phen H2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes showed that the Ln3+ ion was coordinated with six sulfur atoms of three Pdc− and two nitrogen atoms of o-Phen H2O. It was assumed that the coordination number of Ln3+ is eight. The constant-volume combustion energies of the complexes, Δc U, were determined by a precise rotate-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, Δc H m o , and standard molar enthalpies of formation, Δf H m o were calculated. [ABSTRACT FROM AUTHOR]