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61.
An ion-driven gas flow is characterized by the breakdown of a gas into ions in the presence of a high electric potential. Ions flow due to the potential gradient. Mass transfer motivates bulk airflow. In the current study, an ionic air moving device was constructed using needles as ion sources, and a ring as collector. Airflow and efficiency were evaluated at various ring widths and with various numbers of ionization sites. Efficiency was seen to increase with ring width if airflow and distance was held constant and also increased with the number of ionization sites when airflow was held constant. 相似文献
62.
We consider a degenerate or a nearly degenerate dark matter sector where a sizable magnetic moment of a (almost) Dirac type neutral dark matter candidate N is anticipated. Then, due to soft photon exchange, the cross-section in direct detection of N can be enhanced at low Q2 region. We discuss the implication of this type of models in view of the recent CDMS II report. 相似文献
63.
Seok Il Yun Lan Cao Tae-Beom Kang Mongyoung Huh Mario Gauthier 《Journal of Macromolecular Science: Physics》2013,52(12):2318-2333
Arborescent (dendrigraft) copolymers with a branched polystyrene (PS) core grafted at the chain termini with deuterated poly(ethylene oxide) segments (PS-dPEO) were characterized in benzene and acetone by small-angle neutron scattering measurements using the contrast matching technique. While copolymers incorporating a G1 (twice-grafted) PS core aggregated to some extent, the portion of the scattering curve corresponding to non-aggregated copolymer molecules could still be analyzed to determine the shape and segment radial density profile for core and shell. These were derived from the pair distance distribution function P(r) and the scattering length density contrast profile Δρ(r) = ρ(r) ? ρ(solvent), obtained by the indirect Fourier transformation and deconvolution methods. The profiles obtained for the G1 copolymer are consistent with a well-defined PS core–dPEO shell morphology, only observed previously for upper generation (G4) polymers with deuterated PS (dPS) chains grafted randomly on arborescent PS substrates. Detailed morphological analysis could not be carried out for an analogous G3 arborescent PS copolymer terminally grafted with dPEO segments due to extensive aggregation in both solvents. 相似文献
64.
Following Ackleh et al. (2005), we study the multidimensional discrete-time competitive Beverton–Holt equations with equal interspecific competition coefficients. It is shown that competitive exclusion occurs if only one species has the largest carrying capacity. Otherwise, all the species with the largest carrying capacity coexist. In the former case, the system is globally asymptotically stable. In the latter case, the system has a linear stable manifold. 相似文献
65.
Erol Ertan Taylan Akdogan June L. Matthews Michael A. Kovash 《Few-Body Systems》2013,54(7-10):1339-1341
We report new measurements of the neutron–deuteron elastic scattering cross section at energies from 135 to 250 MeV and center-of-mass angles from 80? to 130?. Cross sections for neutron-proton elastic scattering were also measured with the same experimental setup for normalization purposes. Our nd cross section results are compared with predictions based on Faddeev calculations including three-nucleon forces, and with cross sections measured with charged particle and neutron beams at comparable energies. 相似文献
66.
Hyungjin Huh 《偏微分方程通讯》2013,38(2):235-243
We study blow-up solutions of modified Schrödinger maps. We observe the pseudo-conformal invariance by which explicit blow-up solutions can be constructed. 相似文献
67.
Abstract In this paper we introduce generalized ideal-stable regular rings. It is shown that if a regular ring R is a generalized I-stable ring, then every square matrix over I is the product of an idempotent matrix and an generalized invertible matrix and admits a diagonal reduction by some generalized invertible matrices. 相似文献
68.
Ae Kim S Min Byun K Lee J Hoon Kim J Albert Kim DG Baac H Shuler ML June Kim S 《Optics letters》2008,33(9):914-916
We demonstrate that surface plasmon resonance (SPR) is applicable to the optical detection of neural signals. A low-noise SPR sensor was developed as a label- and artifact-free method for the extracellular recording of neural activity. The optical responses obtained from a rat sciatic nerve were highly correlated with simultaneously recorded electrical responses. Additional studies with stimulation intensity and lidocaine further confirmed that the optically measured signals originated from neural activities. 相似文献
69.
Lee JS Kim YY Kim JS Kang YJ 《The Journal of the Acoustical Society of America》2008,123(4):2094-2106
Optimal shape design of a two-dimensional poroelastic acoustical foam is formulated as a topology optimization problem. For a poroelastic acoustical system consisting of an air region and a poroelastic foam region, two different physical regions are continuously changed in an iterative design process. To automatically account for the moving interfaces between two regions, we propose a new unified model to analyze the whole poroelastic acoustical foam system with one set of governing equations; Biot's equations are modified with a material property interpolation from a topology optimization method. With the unified analysis model, we carry out two-dimensional optimal shape design of a poroelastic acoustical foam by a gradient-based topology optimization setting. The specific objective is the maximization of the absorption coefficient in low and middle ranges of frequencies with different amounts of a poroelastic material. The performances of the obtained shapes are compared with those of well-known wedge shapes, and the improvement of absorption is physically interpreted. 相似文献
70.