Kinetic stabilization of Fe film on GaAs(1 0 0): An in situ X-ray reflectivity study

We study the growth of Fe films on GaAs(1 0 0) at a low temperature, 140 K, by in situ X-ray reflectivity (XRR) using synchrotron radiation. The XRR curves are well modeled by a single Fe layer on GaAs both at the growth temperature and after annealed at the room temperature. We found that the surface became progressively rougher during the growth with the growth exponent, β_S = 0.43 ± 0.14. The observed β_S is attributed to the restricted interlayer diffusion at the low growth temperature. The change of the interface width during growth was minimal. When the Fe film was annealed to room temperature, the surface smoothed, keeping the interface width almost unchanged. The confinement of the interface derives from that the diffusion of Ga and As proceeds via the inefficient bulk diffusion, and the overlying Fe film is kinetically stabilized.     

Time-resolved PIV investigation on the unsteadiness of a low reynolds number confined impinging jet

The flow characteristics in a confined slot jet impinging on a flat plate were investigated in low Reynolds number regime by using time-resolved Particle Image Velocimetry technique. The jet Reynolds number was varied from 404 to 1026, where it is presumed that the transient regime exists. We found that the vortical structures in the shear layer are developed with increase of Reynolds number and that the jet becomes remains steady at the Reynolds number of 404. Vortical structures and their temporal evolution are verified and the results were compared with previous numerical studies.     

Effects of hydroxyl‐group end capping and branching on the physical properties of tailored polyethylene terephthalates

Polyethylene terephthalates (PETs) with well‐defined chemical structures were prepared by molecular design, and the effect of the chemical structure on the physical properties of PET was investigated. Hydroxyl‐group end‐capped PETs with η_inh = 0.4–0.6 dL/g exhibited a viscosity behavior similar to Bingham fluids, although other PETs with similar molecular weights (MWs) showed Newtonian flow behavior. This rheological feature was more noticeable for hydroxyl‐group end‐capped branched PETs. In addition, hydroxyl‐group end‐capped branched PETs became solidlike from 80 rad/s as the frequency was increased. On the other hand, hydroxyl end‐capped linear PETs showed a noticeable viscoelastic transition peak around 20 rad/s. High MW linear and branched PETs with η_inh ≥ 0.9 prepared by multistep synthesis showed non‐Newtonian fluid behavior. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1027–1035, 2001     

The impact of investment lags on investment decision

This paper suggests a valuation framework for an investment project through the concept of real options. Generally, in real asset world, decision time and its payment time are not identical. This so-called investment lag problem should be considered when valuing real assets. When investment lags exist, firms’ accommodation capacities play important roles. In this paper, the real effect of investment lag on investment value is tested upon various conditions. We show the valuation process of real assets under the risk-neutral world. The closed-form formula is also provided for valuing real assets, including R&D project.     

Ultraviolet photodissociation at 266 nm of phosphorylated peptide cations

Ultraviolet (UV) photodissociation (PD) experiments using 266 nm light were performed for a series of phosphopeptide cations in a Fourier transform mass spectrometer. The objective of the experiments was to determine whether 266 nm UV irradiation on the phosphopeptide cations would induce unique peptide backbone dissociation. In addition, the general behavior of the phosphate loss (?80 or ?98 Da) was monitored, particularly for those phosphopeptides with a phosphotyrosine residue that itself is a UV chromophore. For phosphopeptides with a UV chromophore, their photodissociation behavior was very similar to that of low‐energy sustained off‐resonance irradiation collisionally activated dissociation (SORI‐CAD), with a few exceptions. For example, b‐ and y‐type peptide backbone fragments were prevalent, and their dephosphorylation behavior was consistent with that of the SORI‐CAD results. For phosphoserine peptides, the loss of a phosphate group was always observed. On the other hand, for phosphotyrosine peptides, the phosphate loss was found to be dependent on the presence of a basic amino group in the sequence and the charge state of the precursor ions, in agreement with the CAD results in the literature. However, hydrogen atom loss or aromatic side chain loss, which is known to be the excited state specific fragmentation pathway, was rarely observed in our 266 nm UV PD experiments, in contrast to the previous UV PD literature (particularly at 220 nm). The mechanism for these observations is described in terms of dominant internal conversion followed by intramolecular vibrational energy redistribution (IVR). Copyright © 2009 John Wiley & Sons, Ltd.     

A method for structured linear total least norm on blind deconvolution problem

The regularized structured total least norm (RSTLN) method finds an approximate solutionx and error matrixE to the overdetermined linear system (H+E)x≈b, preserving structure ofH. A new separation scheme by parts of variables for the regularized structured total least norm on blind deconvolution problem is suggested. A method combining the regularized structured total least norm method with a separation by parts of variables can be obtain a better approximated solution and a smaller residual. Computational results for the practical problem with Block Toeplitz with Toeplitz Block structure show the new method ensures more efficiency on image restoration.