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It has been proven that trace boron additions ( ≤ 0·4 wt-%) to titanium alloys can refine the as-cast microstructure significantly and improve the alloys' mechanical performance. This paper studied the structure of Ti6Al4V-0·1B ingot (Φ 300 mm) produced by vacuum arc remelting (VAR). It has been observed that the structure of Ti6Al4V-0·1B ingot in this experiment is not similar as that of earlier papers. The grain size in the centre of the ingot is 10 times larger than that of grains on the edge. This is because of the cooling speed of ingot as the edge cools faster than the centre in the process of VAR. Furthermore, this paper analysed the transverse and longitudinal tensile properties of Ti6Al4V-0·1B bar (Φ 100 mm) produced by free forging, which found that the transverse tensile elongation is only half of the longitudinal. Lots of TiB rods in transverse fracture were found, but not in longitudinal fracture. Microstructures of transverse and longitudinal bars were observed as well, which found T...

Effects of tritium content on crystal lattice, 3He retention and structure evolution during aging of Ti tritides were investigated using X-ray diffraction, together with analysis of 3He release. Phase transformation and lattice parameters of the Ti tritides varied apparently depending on tritium stoichiometry. Initial tritium content in the Ti tritides showed significant effects on 3He retention due to the existence of α + δ phase boundaries and lattice symmetry in the Ti tritide. The critical contents of 3He release in the α + δ phase region and e phase region were found to be smaller than that in the δ phase region. Variation of crystal lattice structures of α + δ, δ and e phases in the Ti tritides has been investigated, and evolution of 3He during aging is mainly governed by the finite defects of self-interstitial atoms, dislocation loops, 3He bubbles, and dislocations created by formation and growth of 3He bubbles. In the α + δ two phase region, the phase boundaries played an important role to accumulate 3He bubbles and cause inter-bubble fracture. In the e phase region, a preferred condensation of finite defects in basal plane of Ti tritide lattice and formation of a dislocation network were identified.

Low temperature specific heat (C p ) characterization on high-quality HgCr2Se4 single crystal was performed between 0.5 K and 10 K. The result provides conceivable evidence for the existence of competing ferromagnetic (FM) and antiferromagnetic (AFM) interactions in narrow temperature and temperature windows. The result suggests that magnetic interactions competition, as well as the Schottky anomaly, neglected previously in HgCr2Se4 due to the fragile AFM interaction and spin-lattice coupling, also play key roles in giving rise to the exotic magnetic behaviors.

Ultra-thin (∼4.0 nm) HfO2 films were fabricated by plasma oxidation of sputtered metallic Hf films with post low temperature annealing. Advantage of this fabrication process is that the pre-deposition of Hf metal can suppress the formation of interfacial layer between HfO2 film and Si substrate. The as-deposited HfO2 films were subsequently treated by rapid thermal annealing at different temperatures in N2 to investigate the effects of thermal annealing on the physical and electrical properties of HfO2 film. A SiO2-rich interface layer was observed after higher temperature rapid thermal annealing and the phase change of HfO2 film from amorphous into crystalline occurred at about 700∘C. As a result of higher temperature annealing, effective dielectric constant and leakage current were significantly influenced by the formation of interface layer and the crystallization of HfO2 film.

The effects of prolonged annealing (10 h) at low temperature (500°C) have been studied in 20-nm Ni/Si (100) thin films using Rutherford backscattering spectroscopy (RBS), x-ray diffraction (XRD), scanning electron microscopy (SEM) in conjunction with energy-dispersive spectrometry (EDS), and four-point probe techniques. We observe that nickel monosilicide (NiSi) is stable up to 4 h annealing at 500°C. It is also found that, after 6 h and 10 h annealing, severe agglomeration sets in and NiSi thin films tear off and separate into different clusters of regions of NiSi and Si on the surface. Due to this severe agglomeration and tearing off of the NiSi films, sheet resistance is increased by a factor of 2 despite the fact that no NiSi to NiSi2 transition occurs. It is also observed that, with increasing annealing time, the interface between NiSi and Si becomes rougher.

The origins of different gate leakage behaviors for both PMOS and NMOS with ultra-thin nitrided gate oxide have been studied and modeled. Both equivalent oxide thickness (EOT) and barrier lowering are affected the gate leakage. In NMOS with nitrided oxide, the advantage of EOT decrease is larger to offset the barrier lowering, thus improvement on gate current reduction rate ( R J g ). The situation in PMOS is just contrary to the NMOS, therefore the gate leakage increased with increasing nitridation time. We attribute this to the different barrier lowering in conduction band and valence band.

In this letter, I/V curves, output luminance of the organic light emitting diodes (OLEDs) with N2 doped electron transport layer (ETL) have been studied in detail. Experimental results show that the turn on voltage and driving voltage of OLEDs with ETL evaporated in the optimum N2 gas ambient pressure of 1×10−4 Torr are reduced from 3.5 to 1 V and 7.7 to 5.7 V, respectively. The significant improving mechanism has been illustrated comprehensively with a schematic energy diagram model.

It is known that a (7 × 7) superstructure forms in the temperature range 300 to 400 K, upon oxidation of Ni(100). Quantitative measurement of LEED spot intensities reveals the presence of regularly-spaced antiphase walls within the (7 × 7) unit cell. We suggest that such antiphase walls may serve generally to relieve strain in oxide epitaxies.

C8H13ClN4O7, monoclinic, P121/c1 (no. 14), a = 13.061(2) Å, b = 6.508(1) Å, c = 16.963(4) Å, β = 112.20(1)°, V = 1335.0Å3, Z = 4, Rgt(F) = 0.068, wRref(F2) = 0.228, T = 290 K.

Tunneling magnetoresistance (TMR) in Ga(0.9)2Mn(0.08)As/Al-O/Co40Fe40B20 trilayer hybrid structure as a function of temperature from 10 to 50 K with magnetic field vertical bar H vertical bar

The effect of prolonged annealing (10h) at low temperature (200°C) has been studied in 20-nm Ni/Si(100) samples using Rutherford backscattering spectroscopy, X-ray diffraction, and four-point probe techniques. We observedthat at 200°C a considerable amount of Ni 3 Si 2 and Ni 3 1 Si 1 2 was formed. After 10 h annealing at 200°C only a fraction of total amount of Ni has been converted into Ni 3 Si 2 and Ni 3 1 Si 1 2 phases and around 60% of nickel remains unreacted. Formation of the Ni 3 Si 2 and Ni 3 1 Si 1 2 silicides at 200°C is slow and seems to saturate after approximately 140 X 10 1 5 atoms/cm 2 . It is observed that after 2 h annealing the amount of both silicides is almost equal to that after 10 h annealing. After 10 h annealing at 300°C there is no indication of either Ni 3 Si 2 or Ni 3 1 Si 1 2 , and all Ni was consumed and only the stable NiSi phase is detected.

L'appareillage conventionnel de diffraction peut etre utilise pour observer les oscillations des intensites diffractees lors de la croissance de Pt sur Pd(100). Malgre la faible longueur de coherence, les profils sont constitues de deux composants bien separes: ordre a longue distance et l'ordre a courte distance