Should retail stores also RFID-tag ‘cheap’ items?

Despite their implementations in a wide variety of applications, there are very few instances where every item sold at a retail store is RFID-tagged. While the business case for expensive items to be RFID tagged may be somewhat clear, we claim that even ‘cheap’ items (i.e., those that cost less than an RFID tag) should be RFID tagged for retailers to benefit from efficiencies associated with item-level visibility. We study the relative price premiums a retailer with RFID tagged items can command as well as the retailer’s profit to illustrate the significance of item-level RFID-tagging both cheap and expensive items at a retail store. Our results indicate that, under certain conditions, item-level RFID tagging of items that cost less than an RFID tag has the potential to generate significant benefits to the retailer. The retailer is also better off tagging all items regardless of their relative price with respect to that of an RFID tag compared to the case where only the expensive item is RFID-tagged.     

Single shot spatial and temporal coherence properties of the SLAC Linac Coherent Light Source in the hard x-ray regime

We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time τ(c)=(2.0±1.0) fc. The data suggest a mean x-ray pulse duration of (29±14) fs behind the monochromator for (100±14) fc electron pulses.     

PRESSURE-VELOCITY EQUILIBRIUM HYDRODYNAMIC MODELS

This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.     

Die Platiniodide PtI2 und Pt3I8

Platinum Iodides PtI₂ and Pt₃I₈ Powder samples of tetragonal Pt₃I₈ (a = 1166.4(1); c = 1068.2(2) pm) and the cubic α-form of PtI₂ (a = 1109 pm) were obtained by thermal decomposition of PtI₄ in closed quarz ampoules at a I₂ pressure of 2–3 bar and 8 bar, respectively, and at 320°C and 430°C and 430°C, respectively. Single crystals of the monoclinic α-Form of PtI₂ (a = 658.77(6); b = 871.50(34), c = 688.94(11) pm; β = 102.76°; Z = 4) were formed by hydrothermal synthesis from PtI₄, KI, and I₂ at 420°C. In the crystal structure of β-PtI₂ two square planar PtI₄-units are connected by a common edge to planar Pt₂I₆ groups which are linked by common corners to puckered layers. Crystals of Pt₃I₈ synthesized by hydrothermal synthesis from PtI₄, KI, and I₂ at 350°C were twinned and showed defects. As the result of X-ray studies the compound can be formulated as a mixed-valence platinum(II,IV) iodide PtI₄ · 2 PtI₂. Octahedral PtI₆ and square planar PtI₄ units are linked together to a three dimensional skeleton.     

Vibrational dephasing time of a molecular subgroup investigated by ultrashort coherent probing techniques

Normal vibrational modes which are broadened by a distribution of frequencies are coherently excited via transient stimulated Raman scattering. The dephasing time of a subgroup of molecules is observed using a new selective k-vector technique. In this way, one studies the homogeneous linewidth of an inhomogeneously broadened vibrational band. Results are reported on CH-stretching modes of methanol and ethylene glycol.     

Über Osmiumbromide

On Osmiumbromides OsBr₄ was obtained by reaction of OsCl₄ with bromine in a closed system at 330°C and 120 bar Br₂ pressure. The compound crystallizes orthorhombic (a = 633.99(18) pm; b = 1 210.92(16) pm; c = 1 461.5(10) pm; Z = 8; space group Pbca) in a TcCl₄ type structure. OsBr₆ octahedra are connected by two common edges to \documentclass{article}\pagestyle{empty}\begin{document}${}_\infty ^1 \left[ {{\rm OsBr}_{{{\rm 2} \mathord{\left/ {\vphantom {{\rm 2} 1}} \right. \kern-\nulldelimiterspace} 1}} {\rm Br}_{{{\rm 4} \mathord{\left/ {\vphantom {{\rm 4} 2}} \right. \kern-\nulldelimiterspace} 2}} } \right]$\end{document} chains with a cis arrangement of the two non-bridging Br atoms. Mixed crystals OsBr_xCl_4?x(0 < x < 2.3) with CsCl₄ type structure are formed by reactions at lower Br₂ pressure up to 12 bar. They are built up from chains consisting of edge-sharing octahedra. The terminal atoms have a trans arrangement. Attempts to synthesize single crystals of OsBr₃ by decomposition of OsBr₄ resulted in formation of three different phases OsBr_x (3 < x < 4).     

Effect of Pr-Ca substitution on the transport and magnetic behavior of LaMnO3 perovskite

The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO₃ perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good example of these properties is (La_1−2x Pr _x Ca _x )MnO₃ (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T _c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for understanding the structural, transport and magnetic properties are discussed in detail.     

Direct observation of the relaxation time of the symmetric molecular CO2-3 vibration of calcite

The relaxation of the internal A_1g-mode of the CO^2-₃ group (? = 1086 cm^-1) is investigated with picosecond pulses. The measured decay times are 4.4 psec and 8.7 psec at 295 K and 90 K, respectively. Our values are in agreement with spontaneous Raman data. Possible relaxation processes are discussed.     

ansa-Metallocene derivatives: VIII. Syntheses and crystal structures of ethylene-bridged titanocene and zirconocene derivatives with permethylated ring ligands

Ethylene-bridged titanocene and zirconocene derivatives with permethylated ring ligands, C₂H₄(C₅(CH₃)₄)₂TiCl₂ and C₂H₄(C₅(CH₃)₄)₂ZrCl₂, have been synthesized and their crystal structures determined.