Ag44(SR)30(4-): a silver-thiolate superatom complex

Intensely and broadly absorbing nanoparticles (IBANs) of silver protected by arylthiolates were recently synthesized and showed unique optical properties, yet question of their dispersity and their molecular formulas remained. Here IBANs are identified as a superatom complex with a molecular formula of Ag(44)(SR)(30)(4-) and an electron count of 18. This molecular character is shared by IBANs protected by 4-fluorothiophenol or 2-naphthalenethiol. The molecular formula and purity is determined by mass spectrometry and confirmed by sedimentation velocity-analytical ultracentrifugation. The data also give preliminary indications of a unique structure and environment for Ag(44)(SR)(30)(4-).     

Recent advances in conjugated polymers for light emitting devices

A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review.     

Synthesis,characterization and conductivity measurement of poly (2-vinyl pyridine) complex in nano fine state

The objective of the present work is to prepare Poly (2-vinyl pyridine)-I₂ complex in nano fine state. The compounds were characterized by IR, UV, SEM and TGA techniques. Conductivities were determined from 30 to 150⁰C in solid state within a frequency range 42Hz to 500kHz. Conductivity of the complex formed in nano fine state is more stable and shows dramatic improvement compared to the bulky one.     

Innovative Laser-Aided Manufacturing of Patterned Stamping and Cutting Dies: Processing Parameters

We have systematically investigated the process parameters of laser cladding CPM 10V on AISI 1045 steel substrates. Based on experimental results, we have made reasonable approximations and assumptions, developed a simple but realistic process model, relating the maximum clad thickness and various process parameters, for on-line production. The predicted results of this model are in good agreement with the experimental results. A 2.5 kW continuous-wave: CO ₂ laser, a coaxial powder feeding system, and a CAD/CAM system were used for laser cladding experiments. The microstructure of cladding layer, interface and heat-affected zone are characterized by using optical microscopy. Microhardness measurements of laser cladding samples under different treatment conditions are also carried out.     

Effect of vertical stress rest period on deformation behaviour of unbound granular materials: Experimental and numerical investigations

Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials (UGMs) in flexible road pavements. Repeated load pulse characteristics (i.e. shape, loading period and rest period) are the stress configurations used in the experimental set-up to simulate the passing axle loads. Some researchers and standard testing protocols suggest a rest period of varying durations after a loading phase. A thorough review of existing literature and practises has revealed that there is no agreement about the effect of the rest period of vertical stress pulse on the deformation behaviour of the UGMs. Therefore, the main objective of this study is to investigate the effect of repeated stress rest period on the deformation behaviour of UGMs experimentally. Experiments are conducted, both with and without rest period, using basalt and granite crushed rocks from Victoria, Australia. Furthermore, in order to gain insight into the effect of the rest period, finite element modelling is also developed. Both the experimental and modelling results show that the rest period has a noticeable effect on both resilient and permanent deformation behaviours of UGMs. It is, therefore, recommended to take extra precautions while adopting a particular standard testing protocol and to supplement the results by additional tests with different loading configurations.     

A multiwatt all gas-phase iodine laser (AGIL)

The demonstration and characterization of a multiwatt all gas-phase iodine laser (AGIL) are described. A 20-cm subsonic reactor was used to produce NCl (a/sup 1//spl Delta/) for series parametric studies of the I/sup */(/sup 2/P/sub 1/2/)-I(/sup 2/P/sub 3/2/) small-signal gain and extracted power dependence on reactant flow rates and reaction time. The highest measured gain was 2.5/spl times/10/sup -4/ cm/sup -1/ and the highest power observed was 15 W.     

Stability of self-esteem across the life span.

Two studies examined the rank-order stability of self-esteem from age 6 to 83: Study 1 was a meta-analysis of 50 published articles (N = 29,839) and Study 2 analyzed data from 4 large national studies (N = 74,381). Self-esteem showed substantial continuity over time (disattenuated correlations ranged from the .50s to .70s), comparable to the stability found for personality traits. Both studies provided evidence for a robust developmental trend: Self-esteem stability was low during childhood, increased throughout adolescence and young adulthood, and declined during midlife and old age. This trend could not be explained by age differences in the reliability of self-esteem measures, and generally replicated across gender, ethnicity, self-esteem scale, nationality (U.S. vs. non-U.S.), and year of publication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MWCNTs-Reinforced Epoxidized Linseed Oil Plasticized Polylactic Acid Nanocomposite and Its Electroactive Shape Memory Behaviour

A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs) was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA) was first plasticized by epoxidized linseed oil (ELO) in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were incorporated into the ELO plasticized PLA matrix at three different loadings (2, 3 and 5 wt. %), with the aim of making the resulting nanocomposites electrically conductive. The addition of ELO decreased glass transition temperature, and increased the elongation and thermal degradability of PLA, as shown in the results of differential scanning calorimetry (DSC), tensile test, and thermo gravimetric analysis (TGA). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe surface morphology, topography, and the dispersion of MWCNTs in the nanocomposite. Finally, the electroactive-shape memory effect (electroactive-SME) in the resulting nanocomposite was investigated by a fold-deploy “U”-shape bending test. As per the results, the addition of both ELO and MWCNTs to PLA matrix seemed to enhance its overall properties with a great deal of potential in improved shape memory. The 3 wt. % MWCNTs-reinforced nanocomposite system, which showed 95% shape recovery within 45 s at 40 DC voltage, is expected to be used as a preferential polymeric nanocomposite material in various actuators, sensors and deployable devices.