The influence of random microstructure on wave propagation through heterogeneous media

In this paper the influence of mechanical and geometrical properties, both deterministic and stochastic in nature, of a heterogeneous periodic composite material on wave propagation has been analysed in terms of the occurrence of stop-bands. Numerical analyses have been used to identify those parameters that have the most significant effect on the wave filtering properties of the medium. A striking conclusion is that randomness in geometrical properties has a much larger effect than randomness in mechanical properties.     

Precursor synthesis and properties of iron and lithium co-doped cadmium oxide

Journal of Electroceramics - Lithium and iron co-doped cadmium oxide Cd0.9(Li1-xFex)0.1O (x?=?0.1, 0.3, 0.5, 0.7) with NaCl structure has been synthesized using formate of the...     

Minimization of earliness, tardiness and due date penalties on uniform parallel machines with identical jobs

We consider a problem of scheduling n identical nonpreemptive jobs with a common due date on m uniform parallel machines. The objective is to determine an optimal value of the due date and an optimal allocation of jobs onto machines so as to minimize a total cost function, which is the function of earliness, tardiness and due date values. For the problem under study, we establish a set of properties of an optimal solution and suggest a two-phase algorithm to tackle the problem. First, we limit the number of due dates one needs to consider in pursuit of optimality. Next, we provide a polynomial-time algorithm to build an optimal schedule for a fixed due date. The key result is an O(m² log m) algorithm that solves the main problem to optimality.Scope and purpose: To extend the existing research on cost minimization with earliness, tardiness and due date penalties to the case of uniform parallel machines.     

APPLYING SEMANTIC TECHNOLOGY TO BUSINESS NEWS ANALYSIS

This article addresses business news analysis by using artificial intelligence. An interdisciplinary method combining financial textual data mining and ontology-based reasoning is proposed and evaluated. The experiments are performed using a well-known Cyc ontology and textual material from the financial domain. Our experiments show that using semantic technologies for business news analysis helps to provide the user with more relevant answers to his/her queries.     

OntoPlus: Text-driven ontology extension using ontology content,structure and co-occurrence information

This paper addresses the process of semi-automatic text-driven ontology extension using ontology content, structure and co-occurrence information. A novel OntoPlus methodology is proposed for semi-automatic ontology extension based on text mining methods. It allows for the effective extension of the large ontologies, providing a ranked list of potentially relevant concepts and relationships given a new concept (e.g., glossary term) to be inserted in the ontology. A number of experiments are conducted, evaluating measures for ranking correspondence between existing ontology concepts and new domain concepts suggested for the ontology extension. Measures for ranking are based on incorporating ontology content, structure and co-occurrence information. The experiments are performed using a well known Cyc ontology and textual material from two domains – finances and, fisheries & aquaculture. Our experiments show that the best results are achieved by combining content, structure and co-occurrence information. Furthermore, ontology content and structure seem to be more important than co-occurrence for our data in the financial domain. At the same time, ontology content and co-occurrence seem to have higher importance for our fisheries & aquaculture domain.     

Laser‐Directed Assembly of Nanorods of 2D Materials

Herein, the previously unrealized ability to grow nanorods and nanotubes of 2D materials using femtosecond laser irradiation is demonstrated. In as short as 20 min, nanorods of tungsten disulfide, molybdenum disulfide, graphene, and boron nitride are grown in solutions. The technique fragments nanoparticles of the 2D materials from bulk flakes and leverages molecular scale alignment by nonresonant intense laser pulses to direct their assembly into nanorods up to several micrometers in length. The laser treatment process is found to induce phase transformations in some of the materials, and also results in the modification of the nanorods with functional groups from the solvent atoms. Notably, the WS₂ nanoparticles, which are ablated from semiconducting 2H WS₂ crystallographic phase flakes, reassemble into nanorods consisting of the 1T metallic phase. Due to this transition, and the 1D nature of the fabricated nanorods, the WS₂ nanorods display substantial improvements in electrical conductivity and optical transparency when employed as transparent conductors.     

Pinacol rearrangement of jojoba bis-epoxide

Jojoba bis-epoxide (1.6 mmol) undergoes pinacol rearrangement upon reaction with the iodide ion (60 mmol) under slightly acidic conditions, via an iodohydrin as an intermediate, to yield bis-ketojojoba in high yield (92%) after 25 h reflux in THF; no hydroxy derivatives were detected. Since the nucleophilic opening of the epoxide ring is statistically equal on both sides, the rearranged product may have the two carbonyl groups on either side of the original carbon atoms of the two epoxide rings, both completely opened. MS of the rearranged products reveals that the ring opening is approximately equal on both sides of the epoxide ring. Other nucleophiles, such as acetate and amine, open the ring sluggishly without rearrangement.     

Biocatalytic growth of Au nanoparticles: from mechanistic aspects to biosensors design

The H(2)O(2)-mediated enlargement of Au nanoparticles (NPs) and the growth mechanism are described. In addition to the deposition of gold on the NP faces, the formation of nanocrystalline clusters at the intersection of the faces is observed. The detachment of the latter nanoclusters provides additional seeds for the deposition of gold. The biocatalyzed generation of H(2)O(2) in the presence of O(2)/glucose and glucose oxidase enabled the development of an optical biosensor for glucose.     

Photoquantum Hall Effect and Light‐Induced Charge Transfer at the Interface of Graphene/InSe Heterostructures

The transfer of electronic charge across the interface of two van der Waals crystals can underpin the operation of a new class of functional devices. Among van der Waals semiconductors, an exciting and rapidly growing development involves the “post‐transition” metal chalcogenide InSe. Here, field effect phototransistors are reported where single layer graphene is capped with n‐type InSe. These device structures combine the photosensitivity of InSe with the unique electrical properties of graphene. It is shown that the light‐induced transfer of charge between InSe and graphene offers an effective method to increase or decrease the carrier density in graphene, causing a change in its resistance that is gate‐controllable and only weakly dependent on temperature. The charge transfer at the InSe/graphene interface is probed by Hall effect and photoconductivity measurmentes and it is demonstrated that light can induce a sign reversal of the quantum Hall voltage and photovoltaic effects in the graphene layer. These findings demonstrate the potential of light‐induced charge transfer in gate‐tunable InSe/graphene phototransistors for optoelectronics and quantum metrology.     

Dielectric relaxation in vinylidene fluoride–hexafluoropropylene copolymers

The molecular mobility in copolymers of vinylidene fluoride–hexafluoropropylene VDF/HFP of 93/7 and 86/14 ratios has been investigated by means of broadband dielectric relaxation spectroscopy (10^?1–10⁷ Hz), differential scanning calorimetry DSC (?100 to 150°C), and of wide angle X‐ray diffraction WAXS. Four relaxation processes and one ferroelectric‐paraelectric phase transition have been detected. The process of the local mobility β‐ (at temperatures below glass transition point) is not affected by chemical composition of the copolymer and the formed structure. Parameters of segmental mobility in the region of glass transition (α_a‐relaxation) depend on the ratio of comonomer with lower kinetic flexibility. α_c‐relaxation is clearly observed only in VDF/HFP 93/7 copolymer, which is characterized by a higher crystallinity and a higher perfection of crystals of α‐ (α_p‐) phase. Diffuse order–disorder relaxor type ferroelectric transition connected with the destruction of the domains in low‐perfect ferroelectric phase in the amorphous regions has been detected for both copolymers. An intensive relaxation process (α‐process) was observed for both copolymers in high‐temperature region. DSC data shows that it falls on the broad temperature region of α‐phase crystals melting. It is considered to be connected with the space charge relaxation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007