Adjacent Spacing Research Articles

Optimal Viewing Angle Determination for Multiple Vessel Segments in Coronary Angiographic Image

Angiographic image is the perspective projection of the whole body from a 3D space to a 2D imaging plane, in which X-ray is used. As such, topological vasculature information has been lost. In 2D angiograms, foreshortening and overlapping are commonly observed in tubular-like structures. Hence, an optimum viewing angle should be determined to observe an interesting vessel segment (IVS) or an interesting vessel bifurcation (IVB) with minimized foreshortening and overlapping from a limited number of angiographic images. In this study, a novel integrated optimization method is proposed to calculate the optimum viewing angle. In the proposed method, the irregular shape and inter-branch distance of vasculatures are considered. Furthermore, three optimized conditions, including projection foreshortening rate, projection stenosis rate, and projection overlapping rate, are designed and integrated to determine the optimum viewing angle in a single vessel segment. The three conditions, including projection foreshortening, projection stenosis, and projection adjacent spacing rates, are also designed to optimize the viewing angle of bifurcations. To evaluate the performance of the proposed method, we simulated an angiographic image based on X-ray propagating principle by integrating 3D coronary artery tree models and the respective CT volume data. Experimental results demonstrate that the proposed method is very effective and robust; hence, this method can be used to determine the optimum viewing angle of IVS or IVB with irregular stenosis. The proposed method can also help physicians observe the branching structure or stenosis clearly in clinical practice.

Powered-Two-Wheelers kinematic characteristics and interactions during filtering and overtaking in urban arterials

The present paper focuses on the Powered-Two-Wheelers (PTWs) kinematic characteristics and their interactions with the rest of traffic in urban arterials. The factors that may affect the likelihood of PTW drivers to accept critical spacing during filtering and overtaking are also investigated using trajectory data collected from video recordings. The distributional characteristics of the PTW kinematic parameters showed that the patterns of filtering and overtaking have several differences. Further results using Logit models show that PTW speed difference with the rest of traffic, spacing, the existence of heavy vehicles and the occurrence of platoon of moving PTWs (in which the leader is the reference PTW) are significant factors related to the probability of driving in critical spaces through traffic. The likelihood of accepting critical lateral distance from the vehicle being overtaken may be related to the adjacent lane spacing, the speed difference and the existence of a platoon of PTWs. A comparative study between Logit models and equivalent structures of neural networks showed that, in the specific application, neural networks were found to perform better than the Logit models in terms of the model’s discrimination power.

Relations of Rolling Reduction and Microstructure, Texture and Bending Property of Rolled Copper Foils

Annealed pure copper strips were taken as raw materials, and after the processes of foil rolling, the rolled copper foils were fabricated. The effect of foil rolling reduction on microstructure, texture and bending property of the rolled copper foils was studied. The results show that the cross-sectional microstructure of the rolled copper foil consists of elongated grains and the adjacent grain boundaries spacing gradually decreases with the increase of the rolling reduction. When the reduction reaches 90.7%, the adjacent grain boundaries spacing is only 0.52 μm. Rolling textures of the rolled copper foils mainly consist of C, S and B orientation components. With the increase of reduction, the whole intensity of rolling texture increased, and the orientation concentrated continuously. The rolled copper foil with reduction of 90.7% has the best bending resistance, whose fatigue life is more than 300 times. The basic reason for the enhancement in bending performance of copper foils may be that a great foil rolling reduction makes their grains much thinner and their texture highly intensified.

Crosstalk analysis of CMOS buffer driven interconnects for ultra-low power applications

In this paper, an analytical framework to model crosstalk in sub-threshold regime of buffer driven capacitively coupled interconnects has been carried out. The proposed analytical model captures waveform shape and noise peaks quite efficiently. It is analyzed that crosstalk is influenced by variations in interconnect parameters viz. length, width, adjacent spacing and driver size. A comparative analysis between the proposed analytical model and SPICE results shows a very good agreement. The analytical models yield maximum percentage errors of 5.75 % and 6.32 % for negative and positive noise voltages respectively among all the measured observations. The analysis has been carried out for 65 nm technology node.

Simulation models for MIMO wireless channels

In recent years, with the excellence performance in the system spectrum efficiency, MIMO technology has become the concerned topic in the mobile communication technology development process. In order to make better use of MIMO technology, the characteristics of MIMO channel had to be studied, and it is inevitable to accurately model and simulate MIMO wireless channels in different conditions. Wireless communication environment is very complex, so it is difficult to modeling of MIMO channel. In this paper, carrier wave frequency, the maximum Doppler frequency shift, AOA (Angle of Arrival) distribution, power azimuth spectrum and adjacent antenna spacing were token into account integrating. Expressions of the spatial correlation coefficient for different power azimuth spectrum (PAS) distributions were studied. A MIMO channel model was brought forward which has spatial selectivity, frequency selectivity, and time correlation. Simulation shows this related channel capacity is consistent with theoretical channel capacity. Thereby the rationality of this modeling was validated. This model provides powerful implement for simulation of MIMO capability, analysis of system capacity and evaluation of performance. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.1883

Mechanism of directional cracking of Ti,C:sapphire crystal

Directional cracking in Ti,C:sapphire crystals grown along [1120] by Vertical Bridgman method often occurs in the cutting and processing process. In this work, we discuss the characteristic and mechanism of directional cracking of Ti,C:sapphire, and find that directional cracking originates from (1100) lattice plane and spreads along [0001] orientation. Through the Crystalmaker Simulation software, we find that atomic arrangement on (1100) lattice plane is the most sparse and adjacent atomic spacing is the largest along vertical [0001] direction, so in the system (1100) [0001] of lattice has a minimum cracking strength. Irregular carbon inclusions in the cracked Ti,C:sapphire are observed with optical microscopy, scanning electron microscopy (SEM), and X-ray diffractometry. These inclusions cause great internal stress in the cooling process due to thermal expansion mismatch and cracking originating from and spreading in the weak system (1100) [0001] of lattice. As a consequence, macroscopic directional cracking is observed in the Ti,C:sapphire. The study has important theoretical and practical significance for growing high-quality Ti,C:sapphire crystal.

Research on the Nanophase Reinforce Cu Alloy

The microstructure of as-cast state and as-aged of a Cu-0.43Cr-0.22Zr-0.092Mg alloy were analysized by TEM and HRTEM, and the formation mechanics of nanophase during heat treatment were discussed. The research showed that precipitations came from the microstructure of casting alloy which adjacent streak spacing were 1.2nm after aging, which obeyed the Nishyama-Wasserman orientation relationship with the matrix.

Quantification of fracture networks in non-layered, massive rock using synthetic and natural data sets

Two quantitative measures – correlation dimension and maximum Lyapunov exponent – are investigated for quantifying fracture spacing in massive, non-layered rock. The correlation dimension, a measure of fractal dimension, characterizes some aspects of fracture distribution. Relative to other fractal methods used in structural geology, the correlation dimension provides a more rigorous mathematical calculation of the fractal dimension and is particularly robust in cases where data is limited. The maximum Lyapunov exponent calculation also provides quantification of observed distributions of fracture spacing, emphasizing variations in adjacent spacing measurements. The two methods are tested on two different synthetic data sets, to elucidate their usefulness in distinguishing between different distributions, and their sensitivity to population size, average fracture spacing, and standard deviation. Both methods provide accurate results for small population sizes and for a range of average fracture spacings. These methods are then used together to quantify two different fracture sets in the granitoids of the Sierra Nevada Batholith. The results indicate that the different fracture sets – inferred to form from different tectonic processes – have distinctive and quantifiable differences in patterns of fracture spacing.

增损比对激光陀螺影响的研究

The intensity tuning profile is the base for mode selection and frequency stabilization in ring laser gyro(RLG),which is decided directly by the gain-to-loss ratio(GTLR).To improve the performance of the RLG,the dependence of the output bandwidth on the GTLR for two-mode RLG with the gain medium making of the mixture of Neon isotopes(Ne20 and Ne22) is numerically analyzed,with the consideration of comprehensive broadening(both homogeneous broadening and inhomogeneous broadening).It is shown that the output bandwidth increases monotonically with the GTLR of RLG.The intensity tuning profiles with different GTLRs of RLG are simulated and the results show that the intensity tuning profiles can be divided into three typical forms,according to the relative value of the output bandwidth to the adjacent longitudinal mode spacing,exhibiting great agreement with the experimental ones.The potential influence of improper GTLR selection on the application performance of RLG is analyzed and experimentally demonstrated.The ideal selection of GTLR for RLG is proposed,that is,the output bandwidth of the RLG should be approximately equal to its adjacent longitudinal mode spacing.

Mechanism for Stripe Pattern Formation on Hydrophilic Surfaces by Using Convective Self-Assembly

We have studied the formation of stripe patterned films of ordered particle arrays on completely solvophilic substrates by using a self-organization technique. In this method, a substrate immersed in a suspension is withdrawn vertically at a controlled temperature. We have also systematically examined the effects of several experimental parameters. Well-defined stripes spontaneously form at the air-solvent-substrate contact line because of a very dilute suspension in a quasi-static process. The stripe width depends on particle concentration, withdrawal rate, and surface tension, while the stripe spacing depends on the thickness of stripes, surface tension, and type of substrate. A stripe width and the adjacent spacing show a clear correlation, strongly indicating the synchronized formation of a stripe and the next spacing. The evaporation rate does not affect stripe width and spacing but determines the growth rate of stripe patterned films. Based on these results, we propose a new mechanism for stripe formation, which is neither a stick-slip motion of the contact line nor dewetting but a negative feedback of particle concentration caused by a concavely curved shape of the meniscus, demonstrating not only its qualitative but also its quantitative validity.

Correction of Carrier Frequency Offsets in OFDM-Based Spatial Multiplexing MIMO With Distributed Transmit Antennas

This correspondence focuses on the correction of carrier frequency offsets (CFOs) in orthogonal frequency-division multiplexing (OFDM)-based spatial multiplexing multi-input-multi-output (MIMO) with distributed transmit antennas, where the CFOs between the receiver and each transmit antenna are possibly different. Considering macroscopic fading and multipath Rayleigh fading, the average power of the intercarrier interference (ICI) caused by the CFOs is derived, and the optimal CFO correction value is then obtained by maximizing the average signal-to-interference-and-noise ratio (SINR). In particular, when the difference between the minimum and maximum values of the CFOs is no more than half of the adjacent subcarrier spacing, an upper bound of the average ICI power can be obtained, and a closed-form solution of the optimal CFO correction value is derived.

In situ Collapse of Phase‐Separated Structure by Covalent Bond Cleavage at a Branching Point upon Heating

AbstractA branched copolymer containing a degradable polyperoxide linkage at a branching point was synthesized by the radical copolymerization of dienyl‐functionalized polystyrene and polyisoprene macromonomers with molecular oxygen. The ternary mixture of the branched copolymer and the macromonomers showed phase‐separated structure after annealing at 45 and 90 °C. The adjacent spacing of the phase‐separated structure was in the order of submicron to micrometer, which is larger than that of general microphase separated structures, due to the presence of homopolymers (macromonomers). Annealing at 110 °C induced thermal decomposition of the polyperoxide followed by in‐situ collapse and a drastic morphology change in the phase‐separated structure.magnified image

The Microstructural Record of Predation: A New Approach for Identifying Predatory Drill Holes

Abstract Drill holes in prey skeletons are the most common source of data for quantifying predator-prey interactions in the fossil record. To be useful, however, such drill holes need to be identified correctly. Field emission scanning electron microscopy (FE-SEM) and environmental scanning electron microscopy (ESEM) were applied to describe and quantify microstructural characteristics of drill holes. Various specimens, including modern limpets and mussels drilled by muricid snails in laboratory experiments, subfossil limpets collected from a tidal flat (San Juan Island, Washington state, USA), and various Miocene bivalves collected from multiple European sites, were examined for microstructural features. The microstructures observed are interpreted here as Radulichnus-like micro-rasping marks, or predatory microtraces, made by the radula of drilling gastropod predators. The mean adjacent spacing of these microtraces is notably denser than the spacing of muricid radular teeth determined by measurements ta...

Method for the measurement of phase retardation of any wave plate with high precision

We present a measuring method for any wave plate retardation with fairly high precision that utilizes a laser frequency splitting technique. To avoid strong mode competition in measuring half and full wave plates, we use two separate methods: comparing adjacent longitudinal mode spacing, and phase offset with an additional quarter wave plate. Therefore any wave plate can be characterized by a single instrument, and no complicated experimental arrangement or data analysis is required. The performance of the system is demonstrated by determining the phase retardation of several samples to a precision and repeatability better than lambda/10(4); moreover, an error analysis is proposed.

Correlating breakage-fusion-bridge events with the overall chromosomal instability and in vitro karyotype evolution in prostate cancer

Chromosomal instability (CIN) is thought to underlie the generation of chromosomal changes and genomic heterogeneity during prostatic tumorigenesis. The breakage-fusion-bridge (BFB) cycle is one of the CIN mechanisms responsible for characteristic mitotic abnormalities and the occurrence of specific classes of genomic rearrangements. However, there is little detailed information concerning the role of BFB and CIN in generating genomic diversity in prostate cancer. In this study we have used molecular cytogenetic methods and array comparative genomic hybridization analysis (aCGH) of DU145, PC3, LNCaP, 1532T and 1542T to investigate the in vitro role of BFB as a CIN mechanism in karyotype evolution. Analysis of mitotic structures in all five prostate cancer cell lines showed increased frequency of anaphase bridges and nuclear strings. Structurally rearranged dicentric chromosomes were observed in all of the investigated cell lines, and Spectral Karyotyping (SKY) analysis was used to identify the participating rearranged chromosomes. Multicolor banding (mBAND) and aCGH analysis of some of the more complex chromosomal rearrangements and associated amplicons identified inverted duplications, most frequently involving chromosome 8. Chromosomal breakpoint analysis showed there was a higher frequency of rearrangement at centromeric and pericentromeric genomic regions. The distribution of inverted duplications and ladder-like amplifications was mapped by mBAND and by aCGH. Adjacent spacing of focal amplifications and microdeletions were observed, and focal amplification of centromeric and end sequences was present, particularly in the most unstable line DU145. SKY analysis of this line identified chromosome segments fusing with multiple recipient chromosomes (jumping translocations) identifying potential dicentric sources. Telomere free end analysis indicated loss of DNA sequence. Moreover, the cell lines with the shortest telomeres had the most complex karyotypes, suggesting that despite the expression of telomerase, the reduced telomere length could be driving the observed BFB events and elevated levels of CIN in these lines.

Distribution of biomass and carbon in even‐aged stands of Norway spruce (Picea abies (L.) Karst.): A case study on spacing and thinning effects in northern Denmark

The main objective of this case study was to explore the possible influence of forest management on the levels and distribution of biomass and carbon (C) in even-aged stands of Norway spruce [Picea abies (L.) Karst.] in Denmark. Data originated from a long-term thinning experiment and an adjacent spacing experiment at stand ages of 58 and 41 years, respectively. Biomass of 16 trees from different thinning and spacing treatments was measured or partly estimated, and soils were sampled for determination of C stocks. All trees in each plot were measured for stem diameter and some for total height, to allow for scaling-up results to stand-level estimates. For trees of similar size, foliage biomass tended to be higher in the spacing experiment, which was located on slightly more fertile land. Foliage biomass increased with increasing thinning grade, but the effect could not be separated from that of tree size. At stand level, foliage biomass tended to increase with increasing spacing as well as with increasing thinning grade. For branchwood, stems and roots (including below-ground stump), the biomass increased with increasing tree size and stand volume at tree and stand level, respectively, but no differences between stands, spacings or thinning grades were observed, apart from that expressed by tree size or stand volume. At stand level, C stocks of all biomass compartments decreased with increasing thinning grade, while the distribution between compartments was hardly influenced. The ratio between above-ground and stem biomass was about 1.21 at stand level, while the ratio between below- and above-ground biomass was about 0.17. Thinning influenced the C stock of the forest floor and mineral soil oppositely, resulting in no effect of thinning on total soil C.

Chaotic motion in bending induced intramolecular transition: A case study of HCN, HNC and the transition state

Chaotic motion in the bending induced intramolecular transition of HCN, HNC and the transition state is explored by three approaches: (1) Lyapunov analysis, which is based on the classical phase space for the levels, (2) statistical analysis of the distribution of the adjacent level spacing and (3) analysis based on level spacing dips, which integrates the concepts of pendulum dynamics and quantized levels. The three analyses show consistent conclusions: chaos appears only above the transition point and the degree of chaos shows fluctuations as the level energy increases.

The partition function and level density for Yang–Mills–Higgs quantum mechanics

We calculate the partition function $Z(t)$ and the asymptotic integrated level density $N(E)$ for Yang-Mills-Higgs Quantum Mechanics for two and three dimensions ($n = 2, 3$). Due to the infinite volume of the phase space $\Gamma$ on energy shell for $n= 2$, it is not possible to disentangle completely the coupled oscillators ($x^2 y^2$-model) from the Higgs sector. The situation is different for $n = 3$ for which $\Gamma$ is finite. The transition from order to chaos in these systems is expressed by the corresponding transitions in $Z(t)$ and $N(E)$, analogous to the transitions in adjacent level spacing distribution from Poisson distribution to Wigner-Dyson distribution. We also discuss a related system with quartic coupled oscillators and two dimensional quartic free oscillators for which, contrary to YMHQM, both coupling constants are dimensionless.

Dense interleaved bidirectional transmission over 5 x 80 km of nonzero dispersion-shifted fiber

Interleaved bidirectional transmission with adjacent channel spacing of 25 GHz is demonstrated over nonzero dispersion shifted fiber. Errorfree transmission is performed over five 80-km spans. Construction rules for an ultradense bidirectional link with simultaneous suppression of four-wave mixing and Rayleigh-induced crosstalk is are outlined.

Mixed Micromechanics and Continuum Damage Mechanics Approach to Transverse Cracking in [S, 90 n] s Laminates

The stiffness reduction in [S, 90 n ] s laminates due to transverse cracking in 90-layers is analyzed using the synergistic continuum damage mechanics (SCDM) and a micromechanics approach. The material constants involved in the SCDM model are determined using the stiffness reduction data for a reference cross-ply laminate. The constraint efficiency factor, which depends on the stiffness and geometry of neighboring layers, is assumed to be proportional to the average crack opening displacement (COD). The COD as a function of the constraint effect of adjacent layers and crack spacing is described by a simple power law. The crack closure technique and Monte Carlo simulations are used to model the damage evolution: the 90-layer is divided into a large number of elements and the critical strain energy rate G c having the Weibull distribution is randomly assigned to each element. The crack density data for a [02/904] s cross-ply laminate are used to determine the Weibull parameters. The simulated crack density curves are combined with the CDM stiffness reduction predictions to obtain the stiffness versus strain. The methodology developed is successfully used to predict the stiffness reduction as a function of crack density in [±θ/904] s laminates.