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

Synthetic aperture radar (SAR) imaging with an independently moving transmitter and receiver introduces motion artefacts difficult to compensate for, especially between satellites in separate orbits that rendezvous over a target. A solution for polarisation-resolved bistatic frequency-modulated continuous-wave (FMCW) SAR with independently moving platforms is derived and demonstrated through simulation. This solution accounts for the polarisation of the source, susceptibility tensor of the target, and the velocity and acceleration of the transmitter and receiver. The accuracy of the solution is demonstrated by reconstructing simulated point ground targets with a pair of X-band SAR satellites of realistic parameters.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-rsn.2018.5051

Motion compensation of the transmitter and receiver in bistatic frequency-modulated continuous-wave synthetic aperture radar

This work presents the design, development and experimental results obtained from an RF plasma cathode Electron Beam (EB) gun for material processing applications. EB currents of up to 38 mA at −60 kV were extracted and correlated to Optical Emission Spectroscopy (OES) measurements. OES measurements and Argon II ratios were used to compare hollow and flat electrode designs as well as to examine changes in other key plasma parameters (i.e. plasma pressure and excitation power). The spectroscopic measurements and Argon II ratios indicated a higher ionization rate for the hollow electrode geometries and plasma parameters that generated larger EB currents (i.e. higher excitation power and lower pressure). The RF plasma cathode gun was compared to a DC plasma cathode gun. The DC plasma cathode produced larger currents than the RF plasma chamber. This result agreed with the OES measurements, which showed a higher ionisation in the DC plasma.

/pdf/investigation-of-rf-and-dc-plasma-electron-sources-for-38xq9oejo5.pdf

Investigation of RF and DC plasma electron sources for material processing applications

The large scattering cross section of plasmon resonant gold and silver nanoparticles functionalized with the appropriate ligand allows for sensitive and specific detection of nucleic acids and proteins. By varying the size, shape, and material morphology populations with a specific peak plasmon resonance can be prepared. By varying the order and length of plasmon resonant bar segment in a composite nanowire one can obtain a large number of particle populations. Distinct populations can be used for labels for multiplexing or as a platform for biological assays. An larger number of color populations can be obtained with composite nanowires that are fabricated with various lengths of silver, gold, or nickel segments. The order and length of the different plasmon resonance rod segments can be used to uniquely identify a rod population allowing for a large degree of multiplexing within a single sample.

Metal nanoparticles for biodetection

The use of indirect holographic techniques, where radiation characteristics and antenna aperture fields can be obtained from simple intensity measurements made in the near field, has traditionally been restricted to the measurement of large antennas with small angular spread. The following work describes how this limitation can be overcome by synthesising a reference wave with wave vector in excess of the free space wave vector. This enables the radiation characteristics and complex aperture fields of much smaller antennas to be determined. Results are included to show how this technique can be applied to a standard gain pyramidal horn antenna.

Indirect holographic imaging of antennas using an electronically synthesised "slow-wave"

We first summarize the approaches developed in our group allowing for the description of a nonlinear metamaterial media in terms of the effective nonlinear susceptibilities. We subsequently discuss the nonlinear magneto-electric coupling and demonstrate that it can lead to a non-reciprocal nonlinear imaging using a three- or four-wave mixing process, producing an image either on reflection or on transmission.

/pdf/enhancing-nonlinear-response-with-metamaterials-from-2qi4atoaq7.pdf

David R. Smith

Papers

Motion compensation of the transmitter and receiver in bistatic frequency-modulated continuous-wave synthetic aperture radar

Investigation of RF and DC plasma electron sources for material processing applications

Metal nanoparticles for biodetection

Indirect holographic imaging of antennas using an electronically synthesised "slow-wave"

Enhancing nonlinear response with metamaterials: from nonlinear parameters engineering to one-way imaging