Multimode basis selection for spatial multiplexing with limited feedback

Proposed is multimode basis selection in which the active bases are selected at the receiver from the common unitary basis set known at both receiving and transmitting ends, conveyed to the transmitter using limited feedback, and assembled into a precoding matrix at the transmitter. It is shown that the proposed multimode basis selection scheme outperforms both multimode antenna selection and Grassmannian multimode precoding in capacity in correlated fading channels without additional complexity and feedback.     

Characterization and Wideband Modeling of Miniaturized LTCC Helical Inductors

We report fabrication of miniaturized low temperature co-fired ceramic helical (3-D) inductors with more than seven layers of helices and the conductor linewidth of 100mum. We achieve the Q_maxLeff/A product ranging from 200 to 370. Such high values are possible thanks to the drastic reduction of the active area and still acceptably large Q_max and self-resonant frequency. High frequency characterization of the inductors is performed up to 12GHz, and a new equivalent circuit model considering vertical electromagnetic coupling between conductors is shown to reproduce all the measured characteristics     

Optical Properties of Solid Pentacene

We have prepared pentacene films on Si, Al₂O₃, and glass substrates by thermal evaporation and have investigated their optical properties at room temperature over a wide range of frequencies from infrared to ultraviolet (5 meV to 6.5 eV). A series of optical phonon modes and electronic transitions have been observed. The internal vibrational modes in the infrared region match well their molecular counterparts but the electronic transitions show substantial changes from those of a free pentacene molecule. The HOMO–LUMO gap energy of the pentacene films deposited on Al₂O₃ and glass substrates is 1.85 eV.     

Improvement of linewidth enhancement factor in 1.55-μmmultiple-quantum-well laser diodes

The improvement of the linewidth enhancement factor in complex-coupled laser diode (CC-LD), or loss-coupled, was confirmed by measuring the spontaneous emission spectra below threshold from the sidewall of laser diodes. In addition, the serial resistance of the device was measured. The linewidth enhancement factor is improved by the presence of a light absorbing InGaAs grating for loss coupled distributed-feedback (DFB) laser diode (LD). We report the comparison of the linewidth enhancement factors of Fabry-Perot (FP) LD, conventional DFB-LD, and loss coupled DFB-LDs     

Heat shock cognate protein 71-associated peptides function as an epitope for Toxoplasma gondii-specific CD4+ CTL

HLA-DR-restricted CD4+ cytotoxic T-lymphocyte (CTL) lines specific for Toxoplasma gondii (T. gondii)-infected melanoma cells have been established from peripheral blood lymphocytes (PBLs) of a patient with chronic toxoplasmosis. The role of heat shock cognate protein (HSC) 71 in antigen (Ag) processing and presentation of T. gondii-infected melanoma cells to these CD4+ CTL lines was investigated. A human melanoma cell line (P36) pulsed with T. gondii-infected P36 cell-derived HSC71 was lysed by a T. gondii-specific CD4+ CTL line (Tx-HSC-1). The Tx-HSC-1 also killed T. gondii-infected P36 cells. The lytic activity of Tx-HSC-1 against P36 cells pulsed with T. gondii-infected P36 cell-derived HSC71 was inhibited by monoclonal antibodies (mAbs) against HSC71. Anti-human leukocyte antigen (HLA)-DR mAb also partially blocked the lytic activity, whereas anti-HLA-A,B,C mAb did not block the lytic activity. In addition, a flow cytometric analysis with these specific mAbs against HSC71 showed HSC71 to be expressed on the cell surface of T. gondii-infected P36 cells as well as uninfected P36 cells. These data indicate that HSC71 molecules are expressed on human melanoma cell line P36, and that HSC71 may play a potential role in Ag presentation and processing of T. gondii-infected P36 cells to CD4+ CTL.     

One‐Step Transfer and Integration of Multifunctionality in CVD Graphene by TiO2/Graphene Oxide Hybrid Layer

We present a straightforward method for simultaneously enhancing the electrical conductivity, environmental stability, and photocatalytic properties of graphene films through one‐step transfer of CVD graphene and integration by introducing TiO₂/graphene oxide layer. A highly durable and flexible TiO₂ layer is successfully used as a supporting layer for graphene transfer instead of the commonly used PMMA. Transferred graphene/TiO₂ film is directly used for measuring the carrier transport and optoelectronic properties without an extra TiO₂ removal and following deposition steps for multifunctional integration into devices because the thin TiO₂ layer is optically transparent and electrically semiconducting. Moreover, the TiO₂ layer induces charge screening by electrostatically interacting with the residual oxygen moieties on graphene, which are charge scattering centers, resulting in a reduced current hysteresis. Adsorption of water and other chemical molecules onto the graphene surface is also prevented by the passivating TiO₂ layer, resulting in the long term environmental stability of the graphene under high temperature and humidity. In addition, the graphene/TiO₂ film shows effectively enhanced photocatalytic properties because of the increase in the transport efficiency of the photogenerated electrons due to the decrease in the injection barrier formed at the interface between the F‐doped tin oxide and TiO₂ layers.     

Nanodomain Swelling Block Copolymer Lithography for Morphology Tunable Metal Nanopatterning

Ordered metal nanopatterns are crucial requirements for electronics, magnetics, catalysts, photonics, and so on. Despite considerable progress in the synthetic route to metal nanostructures, highly ordered metal nanopatterning over a large‐area is still challenging. Nanodomain swelling block copolymer lithography is presented as a general route to the systematic morphology tuning of metal nanopatterns from amphiphilic diblock copolymer self‐assembly. Selective swelling of hydrophilic nanocylinder domains in amphiphilic block copolymer films during metal precursor loading and subsequent oxygen based etching generates diverse shapes of metal nanopatterns, including hexagonal nanoring array and hexagonal nanomesh and double line array in addition to common nanodot and nanowire arrays. Solvent annealing condition of block copolymer templates, selective swelling of hydrophilic cylinder nanodomains, block copolymer template thickness, and oxygen based etching methods are the decisive parameters for systematic morphology evolution. The plasmonic properties of ordered Au nanopatterns are characterized and analyzed with finite differential time domain calculation. This approach offers unprecedented opportunity for diverse metal nanopatterns from commonly used diblock copolymer self‐assembly.     

Intact hip and knee joint moment in coronal plane with unilateral transfemoral amputee

The incidence of osteoarthritis for lower limb amputees, especially unilateral transfemoral amputees, was higher than that of transtibial amputees. Considering level of amputation and bilateral load asymmetry, we could assumed that joint moments in the coronal plane during gait were highly related to the risk of osteoarthritis. Therefore, this study aimed to examine the hip and knee adduction moments in the coronal plane in persons with unilateral transfemoral amputation during walking through gait analysis. The subjects were 12 unilateral transfemoral amputees and 21 healthy persons. Three-dimensional motion analysis was measured bilaterally from 33 persons during walking to calculate temporal-spatial parameters and joint moments. The analysis compared the prosthetic side and the intact side of the amputee group and then analyzed the moment between both the intact sides of the transfemoral amputee group and the healthy persons. The results showed that the intact knee adduction moment of amputees increased by 32% compared to the prosthetic side and more than twice compared to the control group at terminal stance. But the bilateral hip adduction moment was decreased compared to the control group (p<0.05). Therefore it is expected that the higher knee adduction moment on the intact side may cause secondary complication to unilateral transfemoral amputees, but it is difficult to make connection with hip osteoarthritis.     

Sub‐Nanometer Level Size Tuning of a Monodisperse Nanoparticle Array Via Block Copolymer Lithography

The fabrication and catalytic application of a size‐tunable monodisperse nanoparticle array enabled by block copolymer lithography is demonstrated. Highly uniform vertical cylinder nanodomains are achieved in poly(styrene‐block‐4‐vinylpyridine) (PS‐b‐P4VP) diblock copolymer thin‐films by solvent annealing. The prominent diffusion of the anionic metal complexes into the protonated P4VP cylinder nanodomains occurs through specific electrostatic interactions in a weakly acidic aqueous solution. This well‐defined diffusion with nanoscale confinement enables preparation of the laterally ordered monodisperse nanoparticle array with sub‐nanometer level precise size tuning. The controlled growth of monodisperse nanoparticle arrays is proven by their catalytic use for vertical carbon nanotube (CNT) growth via plasma enhanced chemical vapor deposition (PECVD). Since the size of the catalyst particles is the decisive parameter for the diameters and wall‐numbers of CNTs, the highly selective growth of double‐walled or triple‐walled CNTs could be accomplished using monodisperse nanoparticle arrays.     

巷道围岩破坏形式与原岩应力场的关系研究

运用东北大学开发的RFPA2D程序模拟原岩应力变化时巷道围岩破坏过程,了解无裂纹巷道围岩破坏形式与原岩应力的关系。根据模拟结果,在垂直应力大于水平应力的情况下,破坏主要在巷道侧面上发生。反之,在巷道顶板和底板发生。2个应力之比越大,这样的现象越明显。2个应力相同的情况下,在巷道顶底板和两帮都发生破坏。因此巷道破坏形式与垂直水平应力之间的比值有关而与应力大小无关。