Interconnected Rings Research Articles

Shunt series LC circuit for compact coplanar waveguide notch filter design

A shunt series LC resonant circuit based on an open version of an interconnected split ring resonator (OISRR) is proposed. This OISRR exhibits half the resonant frequency of the split ring resonator, allows a parallel connection with a coplanar waveguide (CPW) section and according to its frequency response is an attractive cell for compact CPW notch filter design. 3 dB stop-band bandwidth lower than 4.5% with more than 11 dB insertion loss in the stop-band can be achieved with a CPW loaded with a single OISRR. The experimental results have confirmed the possibilities of this OISRR, which can be easily connected to CPW antennas to reject undesirable signals.

Spatial Angular Filtering by FSSs Made of Chains of Interconnected SRRs and CSRRs

Two frequency selective surfaces (FSSs) made of an infinite set of parallel 1-D chains of interconnected split ring resonators (I-SRRs) and interconnected complementary split ring resonators (I-CSRRs) are studied. The main result was that the central frequencies of the stopband and passband can be strongly tuned by controlling the angle of incidence.

The Designs of Interconnected Optical Ring Networks

Optical ring networks have been widely implemented as the major metro network architectures. However, as the network coverage expands, the system performance of the single ring structure degrades significantly. In this paper, we propose an interconnected ring topology to enhance the network throughput and efficiency. The carried out simulation results have revealed the superiority of employing such an interconnected architecture. We also discuss the increased complexities and fairness issues induced by such design.

Microstrip notch filters based on open interconnected split ring resonators (OISRRs)

An open interconnected split ring resonator (OISRR) is proposed for use in compact microstrip notch filters. This OISRR behaves as a shunt series L C resonant circuit and allows a parallel connection with a microstrip line. This cell presents half the resonant frequency of the split ring resonator (SRR) and, therefore, is electrically very small. The measured results show a 3 dB stop-band bandwidth lower than 2 % with more than 10 dB insertion loss in the stop band. This OISRR can be useful in microwave communication systems.

A branch‐and‐cut algorithm for the ring spur assignment problem

AbstractThe ring spur assignment problem arises in the design of next‐generation telecommunications networks and has applications in location‐allocation problems. The aim is to identify a minimum cost set of interconnected ring spurs. We seek to connect all nodes of the network either on a set of bounded disjoint local rings or by a single spur edge connected to a node on a local ring. Local rings are interconnected by a special ring called the tertiary ring. We show that the problem is NP ‐Hard and present an Integer Programming formulation with additional valid inequalities. We implement a branch‐and‐cut algorithm and present our conclusions with computational results. © 2013 Wiley Periodicals, Inc. NETWORKS, 2013

The New Alkali Cyclotrisilicate Cs8[Si6O16

AbstractTransparent single crystals of Cs8[Si6O16] have been obtained by a high‐temperature reaction at 900 °C in an arc‐welded niobium crucible. The structure of Cs8[Si6O16] was solved and refined from single crystal X‐ray diffraction data: new structure type, P$\bar{1}$, Z = 2, a = 9.3544(3) Å, b = 11.1152(4) Å, c = 13.5035(5) Å, α = 101.311(3)°, β = 100.958(3)°, γ = 114.121(3)°, R1 = 0.032. The structure of Cs8[Si6O16] contains isolated dimeric cyclotrisilicate anions [Si6O16]8– that are separated by cesium atoms.The anion consists of six vertex‐sharing [SiO4] tetrahedra which form three interconnected rings: two rings consisting of three tetrahedra share edges with the opposite sides of a square of four [SiO4] thetrahedra. With respect to the plane of the four‐membered rings the triangles strike a trans‐type arrangement. [Si6O16]8– is the first example of the third possible structural arrangement in the class of unbranched dimeric cyclotrisilicate anions.

Synthesis and characterization of a novel quaternary metal chalcogenide-Hg3ZnSe3Br2

A novel quaternary metal chalcogenide Hg3ZnSe3Br2 (1) was prepared via a solid-state reaction method and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the space group P-3 of the hexagonal system with two formula units in a cell: a = 7.383(7) A, c = 10.924(9) A, V = 515.6(8) A3, FW = 1063.84, Dc = 6.852 g/cm3, S = 0.713, μ(MoKα) = 65.083 mm−1, F(000) = 884, R = 0.1377 and wR = 0.2720. Compound 1 is characterized by a 2-D layered motif, which is constructed from the interconnected 12-membered Hg6Br6 rings with a chair-like conformation.

Silver(I) complexes with oxazoline-containing bidentate ligands: Syntheses, structures and properties

Six new coordination complexes [Ag2(L)2](NO3)2 (1), [Ag2(L)2](ClO4)2 (2), [Ag3(L)4](SbF6)3 (3), [Ag2(L)2(CH3CN)2](PF6)2 (4), [Ag2(L)2(SO3CH3)2](CH3OH)2 (5) and [Ag2(L)2(SO3CF3)2] (6) were successfully synthesized by reactions of 1,3-bis(2-oxazolinyl)benzene (L) with different Ag(I) salts under the same reaction conditions. Complexes 1 and 2 have the same 16-membered ring structures, which are extended by Ag···O weak interactions and hydrogen bonds to form 3D frameworks. Complex 3 containing two- and four-coordinated Ag(I) atoms has two inter-connected 16-membered rings which are linked together by SbF6- to form a 3D framework. In complex 4, the Ag(I) is three-coordinated by two N atoms from the L ligands and one N atom from acetonitrile solvent and the structure of 4 is also a 16-membered ring. Complexes 5 and 6 have similar 16-member ring structure, and the anions coordinate with Ag(I) atoms. The results reveal that anions can influence on the structure of the complexes. Furthermore, the complexes were characterized by electrospray mass spectrometry.

On the relationship between efficiency and wake structure of a batoid-inspired oscillating fin

AbstractA mechanical representation of batoid-like propulsion using a flexible fin with an elliptical planform shape is used to study the hydrodynamics of undulatory propulsion. The wake is found to consist of a series of interconnected vortex rings, whereby leading and trailing edge vortices of subsequent cycles become entangled with one another. Efficient propulsion is achieved when leading and trailing edge vortices coalesce at the spanwise location where most of the streamwise fluid momentum is concentrated in the wake of the fin. Both the Strouhal number and the wavelength are found to have a significant effect on the wake structure. In general, a decrease in wavelength promotes a wake transition from shedding a single vortex per half-oscillation period to shedding a pair of vortices per half-oscillation period. An increase in Strouhal number causes the wake to bifurcate a finite distance downstream of the trailing edge of the fin into a pair of jets oriented at an acute angle to the line of symmetry. The bifurcation distance decreases with increasing Strouhal number and wavelength, and it is shown to obey a simple scaling law.

Efficient Ethernet Ring Mesh Network Design

Ethernet ring protection (ERP) is an emerging solution for carrier-grade optical Ethernet networking developed as an ITU-T recommendation. The most recent development of the ERP technique provides multi-ring protection in a mesh packet transport network. The ERP configuration and capacity planning in a ring mesh topology can be optimized in the selection of the interconnected ring hierarchy and logical loop prevention block positions. This paper reports the first investigation to understand the designing principles of protected Ethernet ring mesh networks and proposes an optimized design scheme for cost-effective and reliable ERP networking.

Impact Response Analysis of Wire Ring Net System Using the Concept of Particle Method

In Japan, there are many steep mountainous areas and we have local severe rain in the season, thus rock-fall accidents occur in mountain regions year after year. In order to protect an arterial road and the urban areas from the rock-fall accidents, various protective structures had been already constructed. However most of them are made of reinforced concrete and they require huge construction cost. Hence a new economical protective structure has been expected for a long time. From these needs, several high-energy absorption rock-fall nets have been developed. Some of them have specialized shock absorbing device or specialized column which has plastic rotation capacity. On the one hand, wire frame structure (called the wire ring net system) that is composed of interconnected many wire rings of about 30 cm in diameter are predominant in Europe. Because these structures can absorb large kinetic energy of a falling rock due to their deformation capacity, they are introduced from Europe as the highly-effective structures. The wire ring net system is composed of many parts (wire ring, wire rope, supporting post, etc), and it does not require large bases due to its light weight. However, there is no analysis method that can calculate their impact response (dynamic behaviour and energy absorbing capacity), and it has been only confirmed by the full-scale falling weight tests. Although, there are several cases that evaluate the performance by same tests in Japan, the test condition is limited by restriction of test station and its cost. Therefore, this study aims at simulating the impact response of wire ring net system by using the concept of particle method. The following conclusions are obtained from this study. 1) The proposed method can simulate the impact response of the wire ring net system. 2) Fracture of the wire ring net is predicted applying critical strain limit for the material.

All-optical code routing in interconnected optical CDMA and WDM ring networks

We propose an all-optical hybrid network composed of optical code division multiple access (CDMA) rings interconnecting through a reconfigurable wavelength division multiplexing (WDM) metro area ring. This network retains the advantages of both the optical CDMA and WDM techniques, including asynchronous access and differentiated quality of service, while removing the hard limit on the number of subscribers and increasing network flexibility. The all-optical network is enabled by using nonlinear optical loop mirrors in an add/drop router (ADR) that performs code conversion, dropping, and switching asynchronously. We experimentally demonstrate the functionalities of the ADR in the proposed scheme asynchronously and obtain error-free performance. The bit-error rate measurements show acceptable power penalties for different code routes.

ChemInform Abstract: Synthesis and Characterization of the Basic and Non-Basic Members of the Cancrinite-Natrodavyne Family.

Abstract Hydrothermal synthesis has been studied in the system Na2O-SiO2-Al2O3-CO2-H2O at temperatures of 400 and 770 K and pressures of 10 and 150 MPa. The initial concentrations of carbonate and sodium hydroxide were varied, but the Si/Al ratio was always 1.0. Beside cancrinite hydrate and basic cancrinite two new members of the natrodavyne family could be obtained as non-basic and basic species: Na8[AlSiO4]6CO3·4H2O and Na6[AlSiO4]6(CO3)0.75 (OH)0.5·3.4H2O. X-ray powder diffraction, IR spectroscopy and thermoanalytical investigations clearly indicate structural differences as compared with the cancrinites. Stacking disorder of the interconnected six-membered rings of the aluminosilicate framework is to be expected for the new phases. Whereas the X-ray powder patterns of both species resemble the (cubic) sodalites, polarization microscopy reveals their hexagonal symmetry. From this point of view the disordered natrodavyne can be considered as an intermediate phase between sodalite and cancrinite. Thermoanalytical investigations and high temperature X-ray powder diffraction indicate a significant expansion of the framework for both new dehydrated species, in contrast to cancrinite. Structural phase transitions at 960 K for Na8[AlSiO4]6CO3 and 795 K for Na8[AlSiO4]6(CO3)0.75(OH)0.5 were revealed by differential scanning calorimetry indicating a high degree of temperature-induced orientational disorder and dynamics of the CO2−3 guest anions.

1-(3-p-Tolylisoxazol-5-yl)cyclohexanol

The title compound, C16H19NO2, contains two mol­ecules in the asymmetric unit. Each mol­ecule is composed of three inter­connected rings, two essentially planar rings, viz. the isoxazole and the methyl­benzyl aromatic ring [maximum deviations of 0.0027 (13) and 0.0031 (19) Å from the isoxazole and methylbenzyl ring planes, respectively, in the first molecule, 0.0018 (12) and 0.019 (2) Å in the second molecule], and one cyclo­hexa­nol ring having a chair conformation. Although the two mol­ecules have similar bond distances and angles, they differ in the orientation of the cyclo­hexa­nol ring with respect to the tolyl­isoxazole unit. In the first mol­ecule, the dihedral angle between the isoxazole and methyl­benzyl rings is 22.03 (8)° and between the isoxazole and cyclo­hexa­nol rings is 30.15 (8)°. The corresponding values in the second mol­ecule are 6.13 (10) and 88.44 (8)°, respectively. In the crystal, the molecules are linked by O—H⋯O and O—H⋯N hydrogen bonds, building up a zigzag chain parallel to the a axis.

Transparent Conductive Coatings by Printing Coffee Ring Arrays Obtained at Room Temperature

We report here a concept for utilization of the "coffee ring effect" and inkjet printing to obtain transparent conductive patterns, which can replace the widely used transparent conductive oxides, such as ITO. The transparent conductive coating is achieved by forming a 2-D array of interconnected metallic rings. The rim of the individual rings is less than 10 microm in width and less than 300 nm in height, surrounding a "hole" with a diameter of about 150 microm; therefore the whole array of the interconnected rings is almost invisible to the naked eye. The rims of the rings are composed of self-assembled, closely packed silver nanoparticles, which make the individual rings and the resulting array electrically conductive. The resulting arrays of rings have a transparency of 95%; resistivity of 0.5 cm(2) was 4 +/- 0.5 Omega/, which is better than conventional ITO transparent thin films. The silver rings and arrays are fabricated by a very simple, low cost process, based on inkjet printing of a dispersion of 0.5 wt % silver nanoparticles (approximately 20 nm diameter) on plastic substrates. The performance of this transparent conductive coating was demonstrated by using it as an electrode for a plastic electroluminescent device, demonstrating the applicability of this concept in plastics electronics. It is expected that such transparent conductive coatings can be used in a wide range of applications such as displays (LCD, plasma, touch screens, e-paper), lighting devices (electroluminescence, OLED), and solar cells.

Larval convergence in a colonial tunicate: the organization of the sarcotubular complex in Ecteinascidia turbinata (Perophoridae, Phlebobranchiata, Tunicata, Chordata)

Ecteinascidia turbinata is a colonial ascidian that as an adult shares characters with phlebobranch ascidians, whereas the larvae are similar to aplousobranch ascidian larvae. The sarcotubular complex consists of invaginations of the sarcolemma that contact the sarcoplasmatic reticulum via dyads or triads. If present, the invaginations of the sarcolemma in tunicates have been characterized as laminar or tubular. We comparatively investigated the sarcotubular complex of E. turbinata and seven other tunicate species using 3D-reconstruction techniques based on electron micrographs of serial sections. The mononucleate muscle cells in E. turbinata possess intermediate and close junctions and contain several layers of peripheral myofibrillae. The myofibrillae are surrounded by continuous cisternae of the sarcoplasmic reticulum that forms interconnected rings around the z-bands. The invaginations of the sarcolemma are laminar, contacting the sarcoplasamatic reticulum at the height of the z-bands via dyads and triads. We present a clear definition of character states encountered in Tunicata: laminar invaginations are characterized by a width to length ratio of smaller than 1:20, tubular invagination by a width to length ratio of larger than 1:10. Laminar invaginations are found in stolidobranch ascidians and E. turbinata. Tubular invaginations are present in aplousobranch ascidians and appendicularians. This character state distribution across taxa supports the hypothesis that E. turbinata should be included in Phlebobranchiata as suggested by adult characters and that the larval similarities with Aplousobranchiata arose by convergent evolution.

Exact algorithms for the master ring problem

AbstractWe consider the master ring problem (MRP) which often arises in optical network design. Given a network which consists of a collection of interconnected rings R1,…,RK, with n1,…,nK distinct nodes, respectively, we need to find an ordering of the nodes in the network that respects the ordering of every individual ring, if one exists. We show that MRP is NP‐complete, and therefore, it is unlikely to be solvable by a polynomial time algorithm. Our main result is an algorithm which solves MRP in $ Q \cdot \Pi_{k=1}^{K} (n_{k}/\sqrt{2}) $ steps, for some polynomial Q, as the nk values become large. For the ring clearance problem, a special case of practical interest, our algorithm achieves this running time for rings of any size nk ≥ 2. This yields the first nontrivial improvement, by factor of $ (2\sqrt{2})^{K} \approx (2.82)^{K} $, over the running time of the naive algorithm, which exhaustively enumerates all $ \Pi_{k=1}^{K} (2n_{k}) $ possible solutions. © 2008 Wiley Periodicals, Inc. NETWORKS, 2008

Binding energies for alkane molecules on a carbon surface from gas–solid chromatography and molecular mechanics

Gas–solid chromatography was used to determine B 2 s (gas–solid virial coefficient) values for 12 alkanes (10 branched and 2 cyclic) interacting with a carbon powder (Carbopack B, Supelco). B 2 s values were determined by multiple size variant injections within the temperature range of 393 to 623 K with each alkane measured at 5 or 6 different temperatures. The temperature variations of the gas–solid virial coefficients were used to find the experimental adsorption energy or binding energy values ( E ∗ ) for each alkane. A molecular mechanics based, rough-surface model was used to calculate the molecule–surface binding energy ( E cal ∗ ) using augmented MM2 parameters. The surface model consisted of three parallel graphene layers with each layer containing 127 interconnected benzene rings and two separated nanostructures each containing 17 benzene rings arranged in a linear strip. As the parallel nanostructures are moved closer together, the surface roughness increases and molecule–surface interactions are enhanced. A comparison of the experimental and calculated binding energies showed excellent agreement with an average difference of 3.8%. Linear regressions of E ∗ versus E cal ∗ for the current data set and a combined current and prior alkane data set both gave excellent correlations. For the combined data set with 18 linear, branched and cyclic alkanes; a linear regression of E ∗ = 0.9848 E cal ∗ and r 2 = 0.976 was obtained. The results indicate that alkane-surface binding energies may be calculated from MM2 parameters for some gas–solid systems.

Structural Characterization of Quaterphenyl Cation Radical: X-ray Crystallographic Evidence of Quinoidal Charge Delocalization in Poly-p-phenylene Cation Radicals

Quaterphenyl derivative (QP) containing tert-butyl solubilizing groups at the terminal positions yields a stable cation radical salt that was isolated, and its structure was established by X-ray crystallography. The crystal structure of neutral QP and its cation radical (QP+•SbCl6-) provides unequivocal evidence for the quinoidal stabilization of the cationic charge or polaron by smoothing out the torsional motion of the interconnected p-phenylene rings. Such an observation of stabilization of the cationic charge in a poly-p-phenylene (PPP) derivative forms the basis for the noted high conductivities in PPP oligomers in their doped state.

Morphology of the forced oscillatory flow past a finite-span wing at low Reynolds number

A study of the morphology of the vortical skeleton behind a flapping NACA0030 wing with a finite aspect ratio of 3, is undertaken. The motivation for this work originates with the proposal that thrust can be efficiently produced by flapping aerofoils. The test condition corresponds to a Strouhal number of 0.35, Reynolds number, based on aerofoil chord, of 600 and an amplitude of flapping, equal to the chord length of the wing. This test condition corresponds to the optimal thrust-producing case in infinite-span flapping wings. This study investigates the effect of wing three-dimensionality on the structure of the wake-flow. This is accomplished here, by quantitatively describing the spatio-temporal variations in the velocity, vorticity and Reynolds stresses for the finite-span-wing case.Preliminary flow visualizations suggest that the presence of wingtip vortices for the three-dimensional-wing case, create a different vortical structure to the two-dimensional-wing case. In the case of a two-dimensional-wing, the flow is characterized by the interaction of leading- and trailing-edge vorticity, resulting in the formation of a clear reverse Kármán vortex street at the selected test condition. In the case of a three-dimensional-wing, the flow exhibits a high degree of complexity and three-dimensionality, particularly in the midspan region. Using phase-averaged particle image velocimetry measurements of the forced oscillatory flow, a quantitative analysis in the plane of symmetry of the flapping aerofoil was undertaken. Using a triple decomposition of the measured velocities, the morphological characteristics of the spanwise vorticity is found to be phase correlated with the aerofoil kinematics. Reynolds stresses in the direction of oscillation are the dominant dissipative mechanism. The mean velocity profiles resemble ajet, indicative of thrust production. Pairs of strong counter-rotating vortices from the leading- and trailing-edge of the aerofoil are shed into the flow at each half-cycle. The large-scale structure of the flow is characterized by constructive merging of spanwise vorticity. The midspan region is populated by cross-sections of interconnected vortex rings.