Structural, Vibrational and Thermodynamic Properties of AgnCu34-n Nanoparticles

We report results of a systematic study of structural, vibrational and thermodynamical properties of 34-atom bimetallic nanoparticles from the AgnCu34-n family using model interaction potentials as derived from the embedded atom method and in the harmonic approximation of lattice dynamics. Systematic trends in the bond length and dynamical properties can be explained largely on arguments based on local coordination and elemental environment. Thus increase in the number of silver atoms in a given neighborhood introduces a monotonic increase in bond length while increase of the copper content does the reverse. Moreover, based on bond lengths of the lowest coordinated (6 and 8) copper atoms with their nearest neighbors (Cu atoms), we find that the nanoparticles divide into two groups with average bond length either close to (~ 2.58 A) or smaller (~ 2.48 A) than that in bulk copper, accompanied by characteristic features in their vibrational density of states. For the entire set of nanoparticles, vibrational modes are found above the bulk bands of copper/silver. Furthermore, a blue shift in the high frequency end with increasing number of copper atoms in the nanoparticles is traced to a shrinkage of bond lengths from bulk values. The vibrational densities of states at the low frequency end of the spectrum scale linearly with frequency as for single element nanoparticles, however, the effect is more pronounced for these nanoalloys. The Debye temperature was found to be about one third of that of the bulk for pure copper and silver nanoparticles with a non-linear increase with increasing number of copper atoms in the nanoalloys.Comment: 37 pages, 12 figure

Algorithms to Compute the Lyndon Array

We first describe three algorithms for computing the Lyndon array that have been suggested in the literature, but for which no structured exposition has been given. Two of these algorithms execute in quadratic time in the worst case, the third achieves linear time, but at the expense of prior computation of both the suffix array and the inverse suffix array of x. We then go on to describe two variants of a new algorithm that avoids prior computation of global data structures and executes in worst-case n log n time. Experimental evidence suggests that all but one of these five algorithms require only linear execution time in practice, with the two new algorithms faster by a small factor. We conjecture that there exists a fast and worst-case linear-time algorithm to compute the Lyndon array that is also elementary (making no use of global data structures such as the suffix array)

Sistem Koreksi Otomatis Pada Mesin Packaging Dengan Pengendali Plc

Salah satu kecacatan produk dalam kemasan pouch apabila produk tersebut ditemukan overlap. Overlap pada produk sabun refill (isi ulang) merupakan salah satu kecacatan produk yang dapat menyebabkan minat konsumen menurun. Sistem Autocorrection (Pengoreksi-Otomatis) merupakan sistem kendali berbasis PLC (Programmable Logic Controller) yang dirancang untuk mengatasi overlap pada produk pouch. Sensor photo electric amplifier ditanamkan pada sistem ini yang berfungsi sebagai trigger input ke PLC (Programmable Logic Controller) sekaligus pendeteksi overlap yang kemudian sinyal input dari sensor tersebut diolah oleh PLC (Programmable Logic Controller). Output yang dihasilkan berupa gerakan pada sidelay motor (actuator dengan motor AC sebagai penggeraknya) untuk bergeser ke arah kiri atau ke arah kanan tergantung salah satu sensor aktif terlebih dahulu

Design and optimization of compact spot-size converters for silicon photonic devices

The coupling between a silicon nanowire (NW) and a single mode fiber (SMF) is challenging. Design and optimization of compact spot-size converters (SSCs) for silicon photonics devices are presented by using numerically efficient and rigorous full-vectorial finite-element based approaches. The multi-Poly-Silicon layers based SSCs are proposed and optimized for the quasi-TE and quasi-TM polarizations sequentially. The coupling losses can be reduced to 2.72 dB and 2.45 dB for the quasi-TE and quasi-TM polarizations, respectively by using an eleven Poly-Si layers based SSC. A polarization-independent SSC is also proposed based on the phase-matched multi-Poly-Silicon layer and lower taper waveguide for both the quasi-TE and quasi-TM polarizations. Coupling to a lensed fiber with the radius of 2 μm, the optimized polarization-independent SSC is with the coupling losses of 0.34 and 0.25 dB for the quasi-TE and quasi-TM polarizations, respectively. The on-chip integrated SSC opens up the feasibility of a low cost passive aligned fiber-pigtailed electronic-photonics integrated circuits platform