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

The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

/pdf/a-comprehensive-review-of-zno-materials-and-devices-21a3zjadem.pdf

A comprehensive review of zno materials and devices

Spread Spectrum It’s not just for breakfast anymore! Don't blame me, the title is the work of this month's guest columnist, Steve Bible, N7HPR (n7hpr@tapr.org). While cruising the net recently, I noticed a sudden bump in the number of times Spread Spectrum (SS) techniques were mentioned in the amateur digital areas. While QEX has discussed SS in the past, we haven't touched on it in this forum. Steve was a frequent cogent contributor, so I asked him to give us some background. Steve enlisted in the Navy in 1977 and became a Data Systems Technician, a repairman of shipboard computer systems. In 1985 he was accepted into the Navy’s Enlisted Commissioning Program and attended the University of Utah where he studied computer science. Upon graduation in 1988 he was commissioned an Ensign and entered Nuclear Power School. His subsequent assignment was onboard the USS Georgia, a trident submarine stationed in Bangor, Washington. Today Steve is a Lieutenant and he is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California. His areas of interest are digital communications, amateur satellites, VHF/UHF contesting, and QRP. His research area closely follows his interest in amateur radio. His thesis topic is Multihop Packet Radio Routing Protocol Using Dynamic Power Control. Steve is also the AMSAT Area Coordinator for the Monterey Bay area. Here's Steve, I'll have some additional comments at the end.

http://ieeexplore.ieee.org/iel5/5/31355/01457623.pdf

Digital communications

Fundamentals of Plasmonics.- Electromagnetics of Metals.- Surface Plasmon Polaritons at Metal / Insulator Interfaces.- Excitation of Surface Plasmon Polaritons at Planar Interfaces.- Imaging Surface Plasmon Polariton Propagation.- Localized Surface Plasmons.- Electromagnetic Surface Modes at Low Frequencies.- Applications.- Plasmon Waveguides.- Transmission of Radiation Through Apertures and Films.- Enhancement of Emissive Processes and Nonlinearities.- Spectroscopy and Sensing.- Metamaterials and Imaging with Surface Plasmon Polaritons.- Concluding Remarks.

/pdf/plasmonics-fundamentals-and-applications-4syb9877sr.pdf

Plasmonics: Fundamentals and Applications

Electron-beam-induced super-radiant emission from a grating.

Electrical and light emission characteristics of pulsed InAs p-n junction lasers, prepared by diffusing Zn into Sn-doped n-type crystals with a substrate concentration of 1018cm-3, were studied at 4.2, 20.4, and 77°K. Data of variation of capacitance with bias showed these to be abrupt junctions. At injection currents below threshold, the temperature independence of the slopes of the I-V characteristics and the observed variation of the integrated light intensity with current suggest the injection mechanism be photon-assisted tunneling. The peak of the spontaneous radiation shifts with the applied voltage in the expected manner. The time-resolved laser spectra are seen to shift to longer wavelengths during pulsed operation of the laser. The line shift results from joule heating of the junction, and follows the variation of bandgap with temperature. From a plot of threshold current density as a function of reciprocal length gain and loss factors have been calculated. An independent value of the gain factor was obtained from the observed variation with current of the superradiantly narrowed linewidth from a nonlasing structure. Mode-confinement studies indicate that the mode confinement is due to the optical gain in the junction region.

/pdf/electrical-and-optical-characteristics-of-inas-junction-3sgyc90ydx.pdf

Electrical and optical characteristics of InAs junction lasers

A lens is formed out of semiconductor material. The semiconductor produces light which is coupled to the lens. The lens focuses the light and also minimizes refractive reflection. The lens is formed by a graded aluminum alloy, which is oxidized in a lateral direction. The oxidation changes the effective shape of the device according to the grading.

Methods for forming semiconductor lenses on substrates

: Recent progress in the fabrication of low attentuation optical fibers raises the attractive possibility of optical communications via these waveguides. Integration of different optical functions on one substrate in the form of optical circuits will form ideal terminals for such a communication network. The authors discuss the theory, fabrication and performance of a few 'building stones' of such optical circuits. Optical directional couplers capable of coupling light from one channel to another are described and their use as switches is discussed. Distributed feedback for integrated lasers is analyzed. Laser action in a GaAs waveguide, in which distributed feedback was supplied by corrugations fabricated on the surface, is described. Longitudinal and transverse mode control of such a laser is also discussed. (Author)

Components for Integrated Optics.

A three-dimensional index variation grating in bulk BGG31 glass written using neither hydrogen loading nor germanium doping is demonstrated. This material is useful for fabricating ion-exchanged waveguides, and its photosensitivity to ultraviolet (UV) radiation at 248nm has not been previously explored. Intensity measurements of the Bragg diffracted spots indicated a maximum index variation (Delta n) of similar to 4 x 10(-5).

/pdf/grating-formation-in-bgg31-glass-by-uv-exposure-2qzwk8cl02.pdf

Amnon Yariv

Papers

Electron-beam-induced super-radiant emission from a grating.

Electrical and optical characteristics of InAs junction lasers

Methods for forming semiconductor lenses on substrates

Components for Integrated Optics.

Grating formation in BGG31 glass by UV exposure