Physical Sciences and Mathematics Commons^™

Previous Heat Treatment Inducing Different Plasma Nitriding Behaviors In Martensitic Stainless Steels, C A. Figueroa, F Alvarez, D Rg Mitchell, G A. Collins, K T. Short

Australian Institute for Innovative Materials - Papers

In this work we report a study of the induced changes in structure and corrosion behavior of martensitic stainless steels nitrided by plasma immersion ion implantation (PI3) at different previous heat treatments. The samples were characterized by x-ray diffraction and glancing angle x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and potentiodynamic measurements. Depending on the proportion of retained austenite in the unimplanted material, different phase transformations are obtained at lower and intermediate temperatures of nitrogen implantation. At higher temperatures, the great mobility of the chromium yields CrN segregations like spots in random distribution, and the a' -martensite is …

Electron Microscope Studies Of Al-Fe-Si Intermetallics In An A1-11 Percent Alloy, M V. Kral, P N H Nakashima, D Rg Mitchell

Australian Institute for Innovative Materials - Papers

Al-Fe-Si intermetallic particles in both unmodified and highly modified sand-cast eutectic AI-11.7 pct Si alloys were characterized using scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, and convergent beam and selected area electron diffraction. The only two Al-Fe-Si intermetallics observed in this particular alloy are (1) ‘‘Chinese-script’’ morphology, consistent with a description of body-centered cubic a-A119Fe4MNSi2 and (2) plate-shaped, consistent with tetragonal d-A1eFeSi2. The authors are unaware of any other characterization of d-A1eFeSi2 using convergent beam electron diffraction (CBED) and selected area diffraction (SAD) techniques.

1,8,14,20-Tetraoxa-11,23-Dithiatricyclo[21.3.0.09,13]Hexacosa-9,12,21,24-Tetraene, Pawel Wagner, Maciej Kubicki, Mieczyslaw Lapkowski

Australian Institute for Innovative Materials - Papers

Crystals of the title compd. are orthorhombic, space group Pbca; Z = 4. Mols. lie on crystallog. centers of inversion, but have approx. C2h mol. symmetry. The parallel thiophene rings are almost exactly planar; the overall conformation of the mol. is chair-like. The mols. have voids that could, in principle, accommodate small guest mols., although in the crystal structure access to these voids is blocked by neighboring mols.

A Flip-Disorder In The Structure Of 3-[2-(Anthracen-9-Yl)Ethenyl]Thiophene, Pawel Wagner, David L. Officer, Maciej Kubicki

Australian Institute for Innovative Materials - Papers

In the crystal structure of the title compound, C₂₀H₁₄S, the thio­phene rings are disordered; such a flip-type disorder is typical for simple, monosubstituted thio­phene derivatives. Two planar fragments, the thio­phene and the anthracene units, are almost perpendicular in order to relieve the H⋯H steric strains. The crystal packing is determined by van der Waals inter­actions, π–π stacking between the anthracene fragments, and some weak C—H⋯S and C—H⋯π short directional contacts.

2,5-Bis(2-Cyano-2-Thienylvinyl)Thiophene, Pawel Wagner, David L. Officer, Maciej Kubicki

Australian Institute for Innovative Materials - Papers

In the crystal structure of the title compound, C₁₈H₁₀N₂S₃, the terminal thio­phene rings are disordered. This disorder is of a flip-type and has been observed in some other thio­phene derivatives. The mol­ecule as a whole is approximately planar; the dihedral angle between the terminal five-membered rings is 6.0 (2)°. The crystal packing is determined by van der Waals inter­actions, π–π stair-like stacking between the thio­phene rings, and some weak C—H⋯S and C—H⋯π short directional contacts.

3-Methyl-5-Nitrouracil, Maciej Kubicki, Pawel Wagner

Australian Institute for Innovative Materials - Papers

The mol­ecules of the title compound, C₅H₅N₃O₄, are approximately planar. The nitro group makes a dihedral angle of 1.3 (4)° with the plane of the six-membered ring. This coplanar disposition is a reason for the changes in valence angles in the vicinity of the nitro group. Mol­ecules are connected into dimers by means of N—H⋯O hydrogen bonds, and these dimers make larger structures with the help of relatively short C—H⋯O hydrogen bonds.

Efficient Dye Sensitized Solar Cells Based On A 2-Thiophen-2-Yl-Vinyl-Conjugated Ruthenium Photosensitizer And A Conjugated Polymer Hole Conductor, Attila Mozer, Y Wada, K-J Jiang, N Masaki, S Yanagida, Shogo Mori

Australian Institute for Innovative Materials - Papers

Efficient dye-sensitized TiO₂ solar cells based on a 2-thiophen-2-yl-vinyl-conjugated ruthenium photosensitizer and a conjugated polymer poly(3,4-ethylenedioxythiophene) have been fabricated. A maximum power conversion efficiency of 2.6% is achieved when the mesoporous TiO₂ layer is 5–6 μm. The high fill factor (0.74), the open circuit voltage (0.78V), and the linear light intensity dependence of the short circuit current density (4.5mA cm⁻² at 100 mW cm⁻²) make these devices promising for solid state photovoltaic applications.

Electrochemical Study Of 1,3-Indandione Derivatives Of Terthiophenes, Mieczyslaw Lapkowski, Sylwia Plewa, Pawel Wagner, David L. Officer

Australian Institute for Innovative Materials - Papers

Properties and behavior of a group of four newly synthesized derivatives of terthiophene and terthienylenvinylene was studied. All four investigated monomers bear a 1,3-indandione substituent at the central thiophene ring and two of them (ThIV, ThIVM) have additional vinyl bonds introduced between the thiophene rings. In addition, ThIM and ThIVM have 5 positions of the two terminal rings blocked with methyl groups. The measurements were done using cyclic voltamperometry (CV) in solutions of 0.1M Bu₄NBF₄ in CH₂Cl₂. It was found that ThI and ThIV polymerise easily. CV of ThI reveals a reduction peak …

Low-Cost Surface-Mount Led Gas Sensor, Roderick Shepherd, William S. Yerazunis, King Tong Lau, Dermot Diamond

Australian Institute for Innovative Materials - Papers

A low-cost chemical sensor comprising surface-mount light-emitting diodes (LEDs) has been developed for colorimetric gas detection. The device consists of a pair of LEDs connected to a simple PIC microcontroller circuit and in the most basic form, requires the use of only two input-output (I/O) pins on the chip. The key features of this sensor are the use of a LED rather than a photodiode for light detection and an all-digital light detection protocol that leads to a reduction in cost and power consumption by avoiding the need for an analog-to-digital converter. The surface-mount diodes employed are more compact than …

The Effect Of Oxidation On The Structure Of Styryl-Substituted Sexithiophenes: A Resonance Raman Spectroscopy And Density Functional Theory Study, Tracy Clarke, Keith Gordon, David L. Officer, Daina K. Grant

Australian Institute for Innovative Materials - Papers

The structures and vibrational properties of a series of styryl-substituted sexithiophenes and their charged species have been examined using resonance Raman spectroscopy in conjunction with density functional theory calculations. The calculated geometries of the radical cations and dications indicate that the quinoidal charged defects are more strongly localized in the center of the thiophene backbone than is observed in other sexithiophenes. This defect confinement, induced by the positions of the styryl substituents, is particularly evident in the dication species. However, the defect confinement weakens when alkoxy groups are added onto the phenyl rings by causing the extension of the charged …

Growth Of Width-Controlled Nanowires Mno2 From Mesoporous Carbon And Investigation Of Their Properties, Shenmin Zhu, Xiaolin Wang, Wei Huang, Deyue Yan, Honghua Wang, Di Zhang

Australian Institute for Innovative Materials - Papers

One-dimensional α-MnO₂ nanowires with a controlled width of 10–20 nm have been developed by means of ultrasonic waves from mesoporous carbon using KMnO₄ as the precursor. The formation mechanism has been proposed based on the results. A peak around 100 K was detected in the temperature-dependence of magnetization curve, indicating the ferromagnetic state in nanocomposite mesoporous carbon-MnO₂, which is in agreement with the transition temperature found from the magnetization versus applied magnetic field curve. The magnetization versus temperature curve of the obtained MnO₂ nanowires showed a magnetic transition at about 50 K, illustrating that a …

Spin Singlet Pairing In The Superconducting State Of Naxco02 1.3h2o: Evidence From A 59co Knight Shift In A Single Crystal, Guo-Qing Zheng, Kazuaki Matano, Dapeng Chen, C T. Lin

Australian Institute for Innovative Materials - Papers

We report a 59Co Knight-shift measurement in a single crystal of the cobalt oxide superconductor NaxCoO2∙1.3H2O (Tc=4.25 K). We find that the shift due to the spin susceptibility, Ks, is substantially large and anisotropic, with the spin shift along the a-axis Kas being two times that along the c-axis Kcs. The shift decreases with decreasing temperature (T) down to T≈100 K, then becomes a constant until superconductivity sets in. Both Kas and Kcs decrease below Tc. Our results indicate unambiguously that the electron pairing in the superconducting state is in the spin singlet form.

Anomalous Electronic Raman Scattering In Naxcoo2. Yh2o, P Lemmens, K. Y. Choi, E Sherman, Dapeng Chen, C T Lin, F. C. Chou, B Keimer

Australian Institute for Innovative Materials - Papers

Raman scattering experiments on NaxCoO2·yH2O single crystals show a broad electronic continuum with a pronounced peak around 100  cm-1 and a cutoff at approximately 560  cm-1 over a wide range of doping levels. The electronic Raman spectra in superconducting and nonsuperconducting samples are similar at room temperature, but evolve in markedly different ways with decreasing temperature. For superconducting samples, the low-energy spectral weight is depleted upon cooling below T*∼150  K, indicating the opening of a pseudogap that is not present in nonsuperconducting materials. Weak additional phonon modes observed below T* suggest that the pseudogap is associated with charge ordering.

Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond

Australian Institute for Innovative Materials - Papers

A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microsecond) it takes for the photocurrent generated on the detector LED to discharge its capacitance from logic 1 (+5 V) to logic 0 (+1.7 V). The entire instrument provides an inherently digital output of light intensity measurements for a few cents. A …

Comparison Of Small-Field Behaviour In Mgb2, Low And High Temperature Superconductors, Alexey V. Pan, S X. Dou

Australian Institute for Innovative Materials - Papers

Different types of superconductors have been investigated at small magnetic fields (B_a) over wide temperature (T) ranges at different B_a orientations. It has been shown that the temperature dependence of the characteristic field (B*), separating the B_a-independent critical current density (J_c) plateau (single vortex pinning regime) and the region with J_c(B_a) (collective pinning), can be attributed either to the temperature dependence of the magnetic penetration depth for Nb-film and MgB₂bulk superconductors, or to thermally activated processes for Bi-based superconductors and YBa₂Cu₃O_7−δ superconducting …

Influence Of The Iron Sheath On The Local Supercurrent Distribution In Mgb2 Wires, Marie Roussel, Alexey V. Pan, Sihai Zhou, S X. Dou

Australian Institute for Innovative Materials - Papers

The magnetic behavior of iron sheathed magnesium diboride (MgB₂) wires was investigated. Global magnetization measurements have shown unusual critical current density variations compare to a superconductor with no magnetic environment. Local quantitative studies, through MO images, are linked to these global magnetization measurements in order to better understand the observed results. It is shown that the current distribution is affected by the soft magnetic sheath interacting with the superconducting core.

A Study On The Charge-Discharge Mechanism Of Co3o4 As An Anode For The Li Ion Secondary Battery, Yong-Mook Kang, Min-Sang Song, Jin-Ho Kim, Hyun-Seok Kim, Min-Sik Park, Jai-Young Lee, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

Co₃O₄ has shown acceptable electrochemical properties as the anode material of Li secondary batteries. In detail, its capacity reached about 700 mAh/g, twice as high as graphite, and 93.4% of initial capacity was retained after 100 cycles. EIS (electrochemical impedance spectroscopy) analyses revealed that after the 1st cycle, the insertion or extraction of Li ions in Co₃O₄ can occur homogeneously and reversibly (randless-like behavior, homogeneous mixture: Co + Li₂O (in the state of Li insertion), Co₃O₄ (in the state of Li extraction)). In fact, the coulombic efficiency of Co …

A New Magnetoplasmon Sound Wave In A Two-Dimensional Electron Gas Under Electromagnetic Radiation, C Zhang, S Hessami Pilehrood

Australian Institute for Innovative Materials - Papers

We report a new magnetoplasmon mode and a sound-like collective excitation in two-dimensional electronic systems under a weak magnetic field and a low-frequency electromagnetic radiation. The analysis is based on the exact time-dependent wave functions and the exact relation between response function with and without radiation. The new mode discovered here can be used as a generating mechanism of high-frequency radiation from a system whose characteristic energy is low.

Magnetic And Transport Properties Of The Layered Perovskite System Sr2-Yyycoo4 (0< Y < 1), Xiaolin Wang, E Takayama-Muromachi

Australian Institute for Innovative Materials - Papers

Layered perovskite cobalt oxides Sr2-yYyCoO4 (y=0, 0.1, 0.3, 0.5, 0.67, 0.83 and 1) were synthesized under high pressure and high temperature conditions.

Nano-Structured Sno2-Carbon Composites Obtained By In Situ Spray Pyrolysis Method As Anodes In Lithium Batteries, Ling Yuan, Konstantin Konstantinov, Guoxiu Wang, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

In this paper, we report on a series of SnO₂-carbon nano-composites synthesized by in situ spray pyrolysis of a solution of SnCl₂·2H₂O and sucrose at 700 °C. The process results in super fine nanocrystalline SnO₂, which is homogeneously distributed inside the amorphous carbon matrix. The SnO₂ was revealed as a structure of broken hollow spheres with porosity on both the inside and outside particle surfaces. This structure promises a highly developed specific surface area. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images revealed the SnO₂ crystal size is …

Magnetic Ordering And Spin Waves In Na0.82coo2, S P. Bayrakci, I Mirebeau, P Bourges, Y Sidis, M Enderle, J Mesot, Dapeng Chen, C T Lin, B Keimer

Australian Institute for Innovative Materials - Papers

NaxCoO2, the parent compound of the recently synthesized superconductor NaxCoO2∶yH2O, exhibits bulk antiferromagnetic order below ∼20   K for 0.75≤x≤0.9. We have performed neutron scattering experiments in which we observed Bragg reflections corresponding to A-type antiferromagnetic order in a Na0.82CoO2 single crystal and characterized the corresponding spin-wave dispersions. The spin waves exhibit a strongly energy-dependent linewidth. The in-plane and out-of-plane exchange constants resulting from a fit to a nearest-neighbor Heisenberg model are similar in magnitude, which is unexpected in view of the layered crystal structure of NaxCoO2. Possible implications of these observations are discussed.

Nonmagnetic Insulator State In Na1coo2 And Phase Separation Of Na Vacancies, C De Vaulx, M. -H Julien, C Berthier, M Horvatic, P Bordet, V Simonet, Dapeng Chen, C T. Lin

Australian Institute for Innovative Materials - Papers

Crystallographic, magnetic, and NMR properties of a NaxCoO2 single crystal with x≃1 are presented. We identify the stoichiometric Na1CoO2 phase, which is shown to be a nonmagnetic insulator, as expected for homogeneous planes of Co3+ ions with S=0. In addition, we present evidence that, because of slight average Na deficiency, chemical and electronic phase separation leads to a segregation of Na vacancies into the well-defined, magnetic, Na0.8CoO2 phase. The importance of phase separation is discussed in the context of magnetic order for x≃0.8 and the occurrence of a metal-insulator transition for x→1.

Atomic Layer Depostion Of Tio2/Al2o3 Films For Optical Applications, G Triani, P J. Evans, D Rg Mitchell, D J. Attard, K Finnie, M James, T Hanley, B Latella, Kathryn Prince, J Bartlett

Australian Institute for Innovative Materials - Papers

Atomic layer deposition (ALD) is an important technology for depositing functional coatings on accessible, reactive surfaces with precise control of thickness and nanostructure. Unlike conventional chemical vapour deposition, where growth rate is dependent on reactant flux, ALD employs sequential surface chemical reactions to saturate a surface with a (sub-) monolayer of reactive compounds such as metal alkoxides or covalent halides, followed by reaction with a second compound such as water to deposit coatings layer-by-layer. A judicious choice of reactants and processing conditions ensures that the reactions are self-limiting, resulting in controlled film growth with excellent conformality to the substrate.

This …

1-(4-Chlorophenyl)-2-Methyl-4-Nitro-5-(1-Piperidyl)-1h-Imidazole, Maciej Kubicki, Pawel Wagner

Australian Institute for Innovative Materials - Papers

The only specific interactions that influence the crystal packing of the title compound, C15H17ClN4O2, are weak C-H...N and C-H...Cl hydrogen bonds, even though there is a possibility of, for example, pi-pi stacking or halogen bonding. The dihedral angle between the mean planes of the imidazole and benzene rings is 59.82 (5) degrees . The length of the C-N bond connecting the imidazole and piperidine fragments is correlated with the degree of pyramidalization of the piperidine N atom.

Double Injection As A Technique To Study Charge Carrier Transport And Recombination In Bulk-Heterojunction Solar-Cells, G Juska, K Arlauskas, G Sliauzys, A Pivrikas, Attila Mozer, Serdar Sariciftci, Markus Scharber, R Osterbacka

Australian Institute for Innovative Materials - Papers

Ambipolar charge carriermobility and recombination in bulk-heterojunction solar cells based on the mixture of regioregular poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM) has been studied using injection current transients. The experimental results demonstrate double injection with bimolecular recombination limiting the injection current. We found that charge carrier bimolecular recombination is significantly reduced compared to Langevin recombination. We have measured the temperature and electric field dependence of the reduced bimolecular recombination coefficient and the results suggest that the electron and hole pathways are different and the recombination is controlled by the probability of the carriers to meet at the polymer/PCBM interface.

Off-Axis Mgb2 Films Using An In Situ Annealing Pulsed Laser Deposition Method, Yue Zhao, Mihail Ionescu, Josip Horvat, S X. Dou

Australian Institute for Innovative Materials - Papers

Highly smooth and c-axis oriented superconducting MgB₂ thin films were prepared by pulsed laser deposition (PLD) with off-axis geometry. The films were deposited on Al₂O₃–C substrates perpendicularly aligned to a stoichiometric MgB₂ target in a 120 mTorr high purity Ar background gas. An in situ annealing was carried out at 650 °C for 1 min in a 760 Torr Ar atmosphere. Despite the short annealing time, an x-ray θ–2θ scan shows fairly good crystallization, according to the clear c-axis oriented peaks for the films. Both atomic force microscopy and the x-ray diffraction …

Effect Of Doping On Flux Pinning Of Gdba2cu3o7-Y, L Zhang, X B Xu, S Y Ding, M H Zheng, L Xiao, H T Ren, Y L Jiao, Xiaolin Wang, Zhi W. Lin, Jian G. Zhu

Australian Institute for Innovative Materials - Papers

Cylindrical single grains of GdBa 2Cu3Oy sGd-123d with a diameter of 25 mm were successfully fabricated by melt-texture growth sMTGd process in air to study the influence of different starting powders on flux pinning. Measurements of the magnetic critical current density sJcd showed that it was possible to fabricate large Gd-123 single grain with a high Jc at high temperatures and fields by means of properly controlling the starting powders of Gd 2O3, BaCO3 , and CuO before the process.

Charge Transport And Recombination In Bulk Heterojunction Solar Cells Studied By The Photoinducted Charge Extraction By Linearly Increasing Voltage Technique, Attila Mozer, Serdar Sariciftci, Laurence Lutsen, Dirk Vanderzande, R Osterbacka, M Westerling, G Juska

Australian Institute for Innovative Materials - Papers

Charge carriermobility and recombination in a bulk heterojunctionsolar cell based on the mixture of poly[2-methoxy-5-(3,7-dimethyloctyloxy)-phenylene vinylene] (MDMO-PPV) and 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)-C₆₁ (PCBM) has been studied using the novel technique of photoinduced charge carrier extraction in a linearly increasing voltage (Photo-CELIV). In this technique, charge carriers are photogenerated by a short laser flash, and extracted under a reverse bias voltage ramp after an adjustable delay time (t_del). The Photo-CELIV mobility at room temperature is found to be μ = 2 × 10⁻⁴ cm² V⁻¹ s⁻¹, which is almost independent on charge carrier density, but slightly …

Ybco Coated Conductor Using Biaxially Textured Clad Composite Ni-Mn/Ni-Cr Substrate, D Q. Shi, S X. Dou, R. K. Ko, J K. Chung, H S. Kim, H S. Ha, K J. Song, C. Park

Australian Institute for Innovative Materials - Papers

A new biaxially textured composite tape of Ni–4.5% Mn/Ni–1.5% Cr was used as a substrate for a YBCO coated conductor through the RABiTS approach. Multi-layer CeO₂/YSZ/Y₂O₃ buffer layers and YBCO film were deposited on the substrate by pulsed laser deposition. The deposition conditions of the buffer layers and the YBCO were studied and compared. Good biaxial textures have been obtained for buffer layers on composite Ni–4.5% Mn/Ni–1.5% Cr substrates. Scanning electron microscopy on sample cross-sections was used to examine the interface and diffusion of oxygen. The uniform formation of an Ni–Mn–O layer between NiO and …

Recycling Of Ladle Furnace Slags, Sima Aminorroaya-Yamini, Hossein Edris, Ali Tohidi, Jafar Parsi, Bahram Zamani

Australian Institute for Innovative Materials - Papers

Ferrous industry slag is waste product of all steelmaking manufactures. These materials should be reused or stocked. There is abundant literature on the subject of reuse and recycling of blast furnace(BF), basic oxygen furnace(BOF), electric arc furnace(EAF). However, due to the fact that ladle furnaces(LF) have only been constructed in significant numbers since the 1980's, the relatively low slag volume in comparison to the other slags and also the high variability in slag chemistry, very few papers have been published on the recycling of ladle slag as separate materials.

Studies reveal that there is significant percent calcium aluminate in ladle …