Fabrication and characteristics of ZnO thin films deposited by RF sputtering on plastic substrates for flexible display

ZnO thin films were successfully grown on flexible plastic substrates using radio-frequency mag-netron sputtering method at room temperature.The effects of the sputtering power on the quality of the ZnO films have been investigated.The results show that thin films were polycrystalline,with wurtzite structure and a strong preferred c-axis orientation (002).The root-mean-square (rms) surface roughness of the ZnO thin films is 22.1 nm.The ZnO thin films fabricated by sputtering with 70 W sputtering power have a high mobility of 34.33 cm 2 /V·s.The ZnO films are shown to be compatible with flexible display on plastic substrates.     

Trends of internet auctions and agent-mediated Web commerce

Electronic Commerce (EC) is a promising field for applying agent and Artificial Intelligence technologies. In this article, we give an overview of the trends of Internet auctions and agent-mediated Web commerce. We describe the theoretical backgrounds of auction protocols and introduce several Internet auction sites. Furthermore, we describe various activities aimed toward utilizing agent technologies in EC and the trends in standardization efforts on agent technologies. Makoto Yokoo, Ph.D.: He received the B.E. and M.E. degrees in electrical engineering, in 1984 and 1986, respectively, from the University of Tokyo, Japan, and the Ph.D. degree in information and communication engineering in 1995 from the University of Tokyo, Japan. He is currently a distinguished technical member in NTT Communication Science Laboratories, Kyoto, Japan. He was a visiting research scientist at the Department of Electrical Engineering and Computer Science, the University of Michigan, Ann Arbor, from 1990 to 1991. His current research interests include multi-agent systems, search, and constraint satisfaction. Satoru Fujita, D.Eng.: He received his B.E. and M.E. degrees in electronic engineering from the University of Tokyo in 1984 and 1986, respectively. He also received his D.Eng. from the University of Tokyo in 1989 for his research on context comprehension in natural language understanding. He joined NEC Corporation in 1989, and is now a principal researcher of Internet Systems Research Laboratories of NEC. He is engaged in research on mobile agents, distributed systems and Web services.     

Multiple target screening method for robust and accurate in silico ligand screening

We developed a new in silico multiple target screening (MTS) method, based on a multi-receptor versus multi-ligand docking affinity matrixes, and examined its robustness against changes in the scoring system. According to this method, compounds in a database are docked to multiple proteins. The compounds among these proteins that are likely bind to the target protein are selected as the members of the candidate-hit compound group. Then, the compounds in the group are sorted into descending order using the docking score: the first (n-th) compound is expected to be the most (n-th) probable hit compound. This method was applied to the analysis of a set of 142 receptors and 142 compounds using a receptor-ligand docking program, Sievgene [Y. Fukunishi, Y. Mikami, H. Nakamura, Similarities among receptor pockets and among compounds: analysis and application to in silico ligand screening, J. Mol. Graphics Modelling, 24 (2005) 34-45], and the results demonstrated that this method achieves a high hit ratio compared to uniform sampling. We prepared two new scores: the DeltaG score, designed to reproduce the protein-ligand binding free energy, and the hit-optimized score, designed to maximize the hit ratio of in silico screening. Using the Sievgene docking score, DeltaG score and hit-optimized score, the MTS method is more robust than the multiple active-site correction scoring method [G.P.A. Vigers, J.P. Rizzi, Multiple active site corrections for docking and virtual screening, J. Med. Chem., 47 (2004) 80-89].     

Finding ligands for G protein-coupled receptors based on the protein-compound affinity matrix

We developed a novel method of identifying new active ligands based on information related to known active compounds using protein-compound docking simulations, even when the tertiary structure of the actual target receptor protein is unknown. This method was used to find ligands of G protein-coupled receptors (GPCRs), i.e., agonists and antagonists of histamine, adrenaline, serotonin and dopamine receptors. The principal component analysis (PCA) method was applied to the protein-compound affinity matrix, which was given by thorough docking calculations between sets of many protein pockets and chemical compounds. The set of protein pockets did not necessary include the target protein. Each compound was depicted as a point in the PCA space. Compounds in a sphere, whose center was set to the known active compound in the multi-dimensional PCA space or to the average position of several known active compounds, were selected as candidate-hit compounds. Our method was found to be effective for finding the ligands of GPCRs based on known native ligands, even when only the soluble protein structures were used in the docking simulations.     

Study of reactive diluent for air-dried alkyd paint

The conventional air-dried alkyd resin is generally used with 30% to 40% of some organic solvent which dissipates into atmosphere after painting and becomes a factor of air pollution. A reactive diluent was investigated to reduce the content of the organic solvent and to manufacture a high-solid or superhigh-solid paint. 1,1-Bis(1′-methyl-2′-vinyl-4′,6′-heptadienoxy)ethane was found to be suitable as the reactive diluent among the investigated compounds. A small addition of this compound to alkyd paint reduced the content of solvent to less than 15% with a conventional alkyd resin of high molecular weight (high-solid type); and, further, a superhigh solid paint (5% solvent) could be manufactured when this compound was added to a superlong oil-length alkyd resin of low molecular weight.     

Crystallization behavior of polypropylene filled with surface-modified calcium carbonate

Polypropylene (PP) and calcium carbonate (CaCO₃) were mixed in a two-roll mill. The mixed compounds were molded on the plate by using a compression press heater. To improve the affinity of the relation between CaCO₃ and the PP matrix, we modified the CaCO₃ surface through chemical reaction with alkyl dihydrogen phosphates. The CaCO₃ content and size modification affected the crystallization behavior of the filled PP composites. The crystallization temperature in the nonisothermal crystallization process increased with the increase of CaCO₃ content and the decrease of CaCO₃ size. The crystallization temperature revealed the function of log (1 + T_s) (T_s, total surface area of CaCO₃) irrespective of CaCO₃ content and size for modified and unmodified systems, respectively. The shoulder or double crystallization peak of PP composites is recognized for the unmodified system (particle sizes: 1.0 and 4.5 μm).     

Synthesis and blend morphology of BA/BC-type binary graft copolymers composed of polyelectrolyte trunks

Poly(α-methylstyrene) (PMS) macromonomer having one vinylbenzyl group per polymer chain was prepared by the couplings of living PMS with p-chloromethylstyrene (CMS). Subsequently, well-defined poly[acrylic acid (AA)-g-α-methylstyrene (MS)] and poly[4-vinylpyridine (4VP)-g-MS] graft copolymers composed of polyelectrolyte trunks were prepared by radical copolymerization of PMS macromonomer with AA and 4VP monomers, respectively. Binary poly(AA-g-MS)/poly(4VP-g-MS) or poly[AA · triethyl amine (Et₃N) salt-g-MS)/poly(4VP-g-MS) graft copolymer blend films were cast from a benzene/methanol mixture. The morphological results of binary graft copolymer blends are discussed with respect to three-phase separated structures.     

Coexistence of Low Damping and Strong Magnetoelastic Coupling in Epitaxial Spinel Ferrite Thin Films

Low‐loss magnetization dynamics and strong magnetoelastic coupling are generally mutually exclusive properties due to opposing dependencies on spin–orbit interactions. So far, the lack of low‐damping, magnetostrictive ferrite films has hindered the development of power‐efficient magnetoelectric and acoustic spintronic devices. Here, magnetically soft epitaxial spinel NiZnAl‐ferrite thin films with an unusually low Gilbert damping parameter (<3 × 10^?3), as well as strong magnetoelastic coupling evidenced by a giant strain‐induced anisotropy field (≈1 T) and a sizable magnetostriction coefficient (≈10 ppm), are reported. This exceptional combination of low intrinsic damping and substantial magnetostriction arises from the cation chemistry of NiZnAl‐ferrite. At the same time, the coherently strained film structure suppresses extrinsic damping, enables soft magnetic behavior, and generates large easy‐plane magnetoelastic anisotropy. These findings provide a foundation for a new class of low‐loss, magnetoelastic thin film materials that are promising for spin‐mechanical devices.     

Engineering Valley Polarization of Monolayer WS2: A Physical Doping Approach

The emerging field of valleytronics has boosted intensive interests in investigating and controlling valley polarized light emission of monolayer transition metal dichalcogenides (1L TMDs). However, so far, the effective control of valley polarization degree in monolayer TMDs semiconductors is mostly achieved at liquid helium cryogenic temperature (4.2 K), with the requirements of high magnetic field and on‐resonance laser, which are of high cost and unwelcome for applications. To overcome this obstacle, it is depicted that by electrostatic and optical doping, even at temperatures far above liquid helium cryogenic temperature (80 K) and under off‐resonance laser excitation, a competitive valley polarization degree of monolayer WS₂ can be achieved (more than threefold enhancement). The enhanced polarization is understood by a general doping dependent valley relaxation mechanism, which agrees well with the unified theory of carrier screening effects on intervalley scattering process. These results demonstrate that the tunability corresponds to an effective magnet field of ≈10 T at 4.2 K. This work not only serves as a reference to future valleytronic studies based on monolayer TMDs with various external or native carrier densities, but also provides an alternative approach toward enhanced polarization degree, which denotes an essential step toward practical valleytronic applications.