Stochastic relaxed inertial forward-backward-forward splitting for monotone inclusions in Hilbert spaces

Computational Optimization and Applications - We develop a globalized Proximal Newton method for composite and possibly non-convex minimization problems in Hilbert spaces. Additionally, we impose...     

On Necessary Optimality Conditions with Higher-Order Complementarity Slackness for Set-Valued Optimization Problems

Set-Valued and Variational Analysis - We aim to establish Karush-Kuhn-Tucker multiplier rules involving higher-order complementarity slackness under Hölder metric subregularity. These rules...     

Investigation of the Effect of Artificial Internal Defects on the Tensile Behavior of Laser Powder Bed Fusion 17–4 Stainless Steel Samples: Simultaneous Tensile Testing and X-Ray Computed Tomography

Experimental Mechanics - Insufficient data are available to fully understand the effects of metal additive manufacturing (AM) defects for widespread adoption of the emerging technology....     

Controlling the water content of never dried and reswollen bacterial cellulose by the addition of water-soluble polymers to the culture medium

For the modification of medically useful biomaterials from bacterially synthesized cellulose, fleeces of Acetobacter xylinum have been produced in the presence of 0.5, 1.0, and 2.0% (m/v) carboxymethylcellulose (CMC), methylcellulose (MC), and poly(vinyl alcohol) (PVA), respectively, in the Hestrin-Schramm culture medium. The incorporation of the water-soluble polymers into cellulose and their influence on the structure, crystal modifications, and material properties are described. With IR and solid-state ¹³C NMR spectroscopy of the fleeces, the presence of the cellulose ethers and an increase in the amorphous parts of the cellulose modifications (NMR results) have been detected. The incorporation is represented by a higher product yield, too. As demonstrated by scanning electron microscopy, a porelike cellulose network structure forms in the presence of CMC and MC. This modified structure increases the water retention ability (expressed as the water content), the ion absorption capacity, and the remaining nitrogen-containing residues from the culture medium or bacteria cells. The water content of bacterial cellulose (BC) in the never dried state and the freeze-dried, reswollen state can be controlled by the CMC concentration in the culture solution. The freeze-dried, reswollen BC-CMC (2.0%) contains 96% water after centrifugation, whereas standard BC has only 73%. About 98% water is included in a BC-MC composite in the wet state, and about 93% is included in the reswollen state synthesized in the presence of 0.5, 1.0, or 2.0% MC. These biomaterial composites can be stored in the dried state and reswollen before use, reaching a higher water absorption than pure, never dried BC. The copper ion capacity of BC-CMC composites increases proportionally with the added amount of CMC. BC-CMC (0.5%) can absorb 3 times more copper ions than original BC. In the case of 0.5 and 1.0% PVA additions to the culture solution, this polymer cannot be detected in the cellulose fleeces after they are washed. Nevertheless the presence of PVA in the culture medium effects a decreased product yield, a retention of nitrogen-containing residues in the material during purification, a reduced water absorption ability, and a slightly higher copper ion capacity in comparison with original BC. The water content of freeze-dried, reswollen BC-PVA (0.5%) is only 62%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 463–470, 2004     

Electrical and magnetic properties of CoFeAlO thin films

Influences of oxygen-partial pressure and annealing on the electrical and magnetic properties of CoFeAlO thin films were systematically investigated by means of resistivity, permeability, magnetization and ferromagnetic resonance (FMR) measurements. It was found that, with increasing oxygen-partial pressure or under annealing, the electrical resistivity of the film increased and the magnetic softness decreased, which is attributed to the microstructural change of the film. Interestingly, an as-deposited Co_45.30Fe_20.65Al_19.34O_14.71 film was found to exhibit an inverted hysteresis loop with negative coercivity, and this peculiar phenomenon disappeared upon effects of oxygen-partial pressure and annealing. It was also found that the as-deposited films owned a narrow FMR line width that increased with increasing oxygen-partial pressure or under annealing.     

High-frequency characteristics of CoFeVAlONb thin films

High-frequency characteristics of CoFeVAlONb thin films were studied. A thin film of Co_43.47Fe_35.30V_1.54Al_5.55O_9.93Nb_4.21 is observed to exhibit excellent magnetic properties; magnetic coercivity of 1.24 Oe, uniaxial in-plane anisotropy field of 66.99 Oe, and saturation magnetization of 19.8 kG. The effective permeability of the film is as high as 1089 and is stable up to 1.8 GHz, and with ferromagnetic resonance over 3 GHz. This film also has very high electrical resistivity of about 628 μΩ cm. These superior properties make it ideal for high-frequency magnetic applications.     

The convex hull property and topology of hypersurfaces with nonnegative curvature

We prove that, in Euclidean space, any nonnegatively curved, compact, smoothly immersed hypersurface lies outside the convex hull of its boundary, provided the boundary satisfies certain required conditions. This gives a convex hull property, dual to the classical one for surfaces with nonpositive curvature. A version of this result in the nonsmooth category is obtained as well. We show that our boundary conditions determine the topology of the surface up to at most two choices. The proof is based on uniform estimates for radii of convexity of these surfaces under a clipping procedure, a noncollapsing convergence theorem, and a gluing procedure.     

The ALTO project at IPN-Orsay

The availability of both a tandem deuteron beam and a linac electron beam, the latter converted into Bremsstrahlung, at the new ALTO facility at IPN-Orsay offers a unique opportunity to compare the performance of a laser ion guide under different regimes. The ALTO accelerator has delivered its first electron beam at the end of 2005 and a design for a gas-cell prototype is being studied.     

New labdane-type diterpenoids from Leonurus heterophyllus SW

Five new natural labdane-type diterpenoids (5-9), designated leoheteronins A-E, together with four known diterpenoids (1-4), two phytosterols as a mixture of beta-sitosterol and stigmasterol, and the flavone genkwanin (10) were isolated from the aerial parts of Leonurus heterophyllus SW. (Lamiaceae) collected in northern Vietnam. Compound 1 was isolated for the first time from a Leonurus species, and 10 is considered to be a chemotaxonomic marker of the Leonurus genus. Their structures were determined using spectroscopic analyses.     

Homo-dinuclear σ-alkynyl complexes: past, present and opportunities

Homo-dinuclear alkynyl complexes with a distinct metal–metal bond constitute a rapidly growing field, where the focus is placed on compounds based on ruthenium, molybdenum, tungsten or rhodium. Interesting characteristics of these complexes include paramagnetism, intense charge-transfer absorptions, tunable bridging ligands, which may not be easily accessible in mononuclear acetylide systems. These complexes have significant potential for use in both molecular electronics and supramolecular chemistry. In this short account, previous work in this area is assessed, and each of the major groups of complexes is discussed in terms of both the synthetic strategies and structural motifs.