There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons--in particular their interaction with light--can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.

/pdf/surface-plasmon-subwavelength-optics-5e55p12p4o.pdf

Surface plasmon subwavelength optics

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

A novel design methodology for multiplexer design is presented. For the first time, finite element EM based simulators and space-mapping optimization are combined to produce an accurate design for manifold coupled output multiplexers with dielectric resonator (DR) loaded filters. Finite element EM based simulators are used as a fine model of each multiplexer channel and a coupling matrix representation is used as a coarse model. Fine details such as tuning screws are included in the fine model. Therefore channel dispersion and spurious modes are taken into account. The DR filter channel design parameters are kept bounded during optimization. Our approach has been used to design large-scale manifold coupled output multiplexers and it has significantly reduced the overall tuning time compared to traditional techniques. The technique is illustrated through design of a 10-channel output multiplexer with 5-pole DR filter based channels.

EM based design of large-scale dielectric resonator multiplexers by space mapping

We propose and experimentally demonstrate a polarization-selective waveguide hologram at optical wavelengths, based on an all-dielectric metamaterial multilayer system. We show that two spatially separated or overlapped holographic images can be produced with two orthogonally polarized beams, incorporated into a binary computer generated hologram (CGH). These two images can be combined into a single 3D stereoscopic image observable using linearly or circularly polarized glasses. The two polarized beams can also be utilized to construct radially and azimuthally polarized "vortex" beams. The fundamental and first higher-order TM and TE modes of an optical waveguide are used to guide the two polarization states with distinct propagation constants. The two guided waves act as spatially distinct reference waves such that the integrated, on-chip hologram can distinguish the two and provide two independent images corresponding to the two polarizations. Polarization selective waveguide holograms can be used in a diverse set of applications, from chip-scale displays and augmented reality (AR) to optical trapping.

Polarization-selective waveguide holography in the visible spectrum.

We examine the effect of alignment errors on the performance of a frequency-diverse imaging system composed of metamaterial apertures. In a frequency-diverse imaging system, a sequence of distinct radiation patterns, indexed by frequency, provides measurements of the spatial content of a scene. This set of measurements can then be used to obtain a high-fidelity estimate of the scene using computational imaging techniques. As with any computational imaging system, realizing the full potential of the frequency-diverse system requires accurate characterization of the complex radiation patterns. This characterization entails precise knowledge of the locations and orientations of the transmitters and receivers; any discrepancy between the modeled and actual locations will introduce phase error and degrade the quality of image reconstructions. Here, we study the effect of various misalignment errors on the performance of a sparse, bi-static, frequency diverse imaging system and provide an estimate on the levels of error within which the frequency-diverse apertures can reconstruct high quality images. Depending on the misalignment type (i.e., displacement, rotation) and direction the phase error can change significantly. As a result, for instance, we show that the imaging system is significantly less sensitive to cross-range displacement errors than to range displacement errors. We also show that the displacement errors are reduced for larger systems comprising many sub-apertures, due to the reduced averaged phase error. We find the impact of rotational errors is small compared to that of the displacement errors. However, as the sub-aperture size increases, rotational errors become more pronounced, becoming severe for larger sub-apertures with multiple feeds.

https://jpier.org/pierb/pierb70/08.16052801.pdf

Investigation of alignment errors on multi-static microwave imaging based on frequency-diverse metamaterial apertures

Detailed 2D turbulence measurements from the DIII-D tokamak provide an explanation for how resonant magnetic perturbations (RMPs) raise the L-H power threshold $P_\textrm{LH}$ [P. Gohil et al., Nucl. Fusion 51, 103020 (2011)] in ITER-relevant, low rotation, ITER-similar-shape plasmas with favorable ion $\nabla B$ direction. RMPs simultaneously raise the turbulence decorrelation rate $\Delta \omega_D$ and reduce the flow shear rate $\omega_\textrm{shear}$ in the stationary L-mode state preceding the L-H transition, thereby disrupting the turbulence shear suppression mechanism. RMPs also reduce the Reynolds stress drive for poloidal flow, contributing to the reduction of $\omega_\textrm{shear}$ On the ~100 {\mu}s timescale of the L-H transition, RMPs reduce Reynolds-stress-driven energy transfer from turbulence to flows by an order of magnitude, challenging the energy depletion theory for the L-H trigger mechanism. In contrast, non-resonant magnetic perturbations, which do not significantly affect $P_\textrm{LH}$, do not affect $\Delta \omega_D$ and only slightly reduce $\omega_\textrm{shear}$ and Reynolds-stress-driven energy transfer.

Effect of magnetic perturbations on turbulence-flow dynamics at the L-H transition on DIII-D

We demonstrate a computer-generated metasurface hologram in which four distinct images are encoded at four different W-band (75–110 GHz) frequencies. The metasurface hologram consists of a planar array of resonant metamaterial elements excited by a collimated reference beam incident on the hologram at an oblique angle. Each of the images is encoded by a subset of metamaterial elements that are resonant at the specific excitation frequency and are spatially positioned to achieve a desired phase distribution in the plane in conjunction with the reference wave. The phase-only hologram is optimized using the Gerschberg–Saxton algorithm. The four well-defined images are produced at specific distances within the Fresnel zone of the aperture.

David R. Smith

Papers

EM based design of large-scale dielectric resonator multiplexers by space mapping

Polarization-selective waveguide holography in the visible spectrum.

Investigation of alignment errors on multi-static microwave imaging based on frequency-diverse metamaterial apertures

Effect of magnetic perturbations on turbulence-flow dynamics at the L-H transition on DIII-D

Multispectral metasurface hologram at millimeter wavelengths.