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

Tunable semiconductor lasers are disclosed requiring minimized coupling regions. Multiple laser embodiments employ ring resonators or ring resonator pairs using only a single coupling region with the gain medium are detailed. Tuning can be performed by changing the phase of the coupling coefficient between the gain medium and a ring resonator of the laser. Another embodiment provides a tunable laser including two Mach-Zehnder interferometers in series and a reflector coupled to a gain medium.

/pdf/tunable-semiconductor-lasers-45hqk8hdo6.pdf

Tunable semiconductor lasers

The small-signal modulation response of semiconductor lasers with a very small mirror reflectivity is analyzed. Superluminescent effects inside the laser cavity provide yet another mechanism for damping relaxation oscillation resonance. These results can serve as useful guides in designing high frequency semiconductor lasers.

/pdf/effect-of-superluminescence-on-the-modulation-response-of-8qsdyhkd96.pdf

Effect of superluminescence on the modulation response of semiconductor lasers

The possibility of phononless free-carrier absorption in quantum well heterojunction superlattices was investigated. Order of magnitude calculation showed that the absorption coefficient was significantly enhanced over the phonon-assisted process. Important aspects of the enhancement in the design of infrared photodetectors are discussed.

/pdf/internal-photoemission-from-quantum-well-heterojunction-3ikda39t6g.pdf

Internal photoemission from quantum well heterojunction superlattices by phononless free‐carrier absorption

The characteristics of an optical fiber external resonator in conjunction with (GaAl)As stripe geometry lasers are described. We have observed a 6–10% reduction in the threshold current and have obtained 150 ps pulses at gigahertz repetition rates. The fiber resonator has also been used to quench self‐pulsations in a (GaAl)As injection laser. In order to explain many of our results we have used a model that uses the conventional semiconductor rate equations modified by the addition of saturable electron traps and the effects of the external cavity. Our results predict many of the self‐locking effects observed in injection lasers operating in an external cavity. Furthermore, the degree of self‐locking will be a strong function of the external cavity length and the density of saturable absorbers.

Studies of (GaAl)As injection lasers operating with an optical fiber resonator

Low threshold InGaAsP/InP injection lasers on semi‐insulating InP substrates have been developed with mirrors fabricated by the microcleavage technique. Miniature suspended bridges containing the laser channels have been formed and then microcleavage has been accomplished by the use of ultrasonic vibrations. Lasers with current thresholds as low as 18 mA with 140‐μm cavity length and with 35–45% differential quantum efficiency have been obtained.

/pdf/low-threshold-ingaasp-inp-lasers-with-microcleaved-mirrors-2g8vxmx5ok.pdf

Amnon Yariv

Papers

Tunable semiconductor lasers

Effect of superluminescence on the modulation response of semiconductor lasers

Internal photoemission from quantum well heterojunction superlattices by phononless free‐carrier absorption

Studies of (GaAl)As injection lasers operating with an optical fiber resonator

Low threshold InGaAsP/InP lasers with microcleaved mirrors suitable for monolithic integration