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. ...

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A comprehensive review of zno materials and devices

Additive manufacturing of metallic components – Process, structure and properties

Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid–vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by the solid–vapour phase technique and their corresponding growth mechanisms. The application of ZnO nanobelts as nanosensors, nanocantilevers, field effect transistors and nanoresonators is demonstrated.

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Zinc oxide nanostructures: growth, properties and applications

One-dimensional nanostructures hold the promise of becoming critical elements for next generation nanoscale electronic and photonic devices. While significant efforts have been devoted to the development of nanotube or nanowire based transistors, little has been done on their photonic counterpart. Here we summarize our recent efforts on one-dimensional crystalline nanostructures, in particular, the zinc oxide (ZnO) nanowires grown on a sapphire substrate. ZnO is a wide bandgap (3.37 eV) compound semiconductor that is especially suitable for blue and ultraviolet (UV) optoelectronic applications. Room-temperature optical energy conversion and stimulated UV light emission from ZnO nanowires are emphasized, along with a discussion of potential applications of nanoscale lasers.

Optical energy conversion in crystalline nanowires

A method and apparatus for analyzing one or more elements of targeted moving food surfaces uses laser-induced breakdown spectroscopy to detect the presence, absence, or amount of an element on a heterogeneous surface of an object, including surfaces of food products. A laser is used to quantify an element concentration without destroying the object. The method can be configured to include an automated on-line system comprising a closed-loop feedback control system operable to select a predetermined concentration.

Method for elemental analysis in a production line

In this work, a dual-beam measurement technique is presented to measure the short-time-scale optical properties of novel materials. It is shown that the picosecond continuum probe source obtained from nonlinear interaction with H2O/D2O is highly variable and does not permit detection of small changes in absorption /transmission spectra. The dual-beam approach is proposed to allow simultaneous measurement of a sample's properties in both the excited and steady states. As an example, the technique is applied to the picosecond transmission spectrum of light-emitting porous silicon. Photo-induced absorption is observed at a level that could not be detected without the new technique.

The dual beam picosecond continuum technique for measurement of short-time-scale transmission spectra

Optimally tuned laser light illumination through the back of multilayered license-plate decals provided nondestructive absolute identification of a latent registration number.

Laser Interrogation of Latent Vehicle Registration Number

A laser-based ultrasonic system for non-contact and non-destructive measurement of the elastic properties of paper was demonstrated on a paper manufacturing machine during commercial operation with paper moving around 20 m/s. We believe this to be the highest sample traveling speed reported to date for a commercial application of laser ultrasonics. Ultrasonic waves were generated in the paper with a pulsed Nd:YAG laser at 1064 nm wavelength and detected with a Mach-Zehnder interferometer coupled with a scanning mirror/timing system to compensate for paper motion. Measurements of the flexural rigidity (FR) and out-of-plane shear rigidity (SR) of the paper web were done automatically by fitting the frequency dependence of the phase velocity of Ao mode Lamb waves to a model wave propagation equation. Variation in FR and SR across the width of the paper sheet (cross-direction profiles), effects of changes in paper manufacturing process variables on measured FR and SR, comparisons with traditional mechanical stiffness tests are presented. The sensor head is fully optical and thus measures the web properties without any contact. This laser-ultrasonics system combines a very reasonable cost with a relatively small footprint and low power consumption due to the low power output of the lasers that are used. Finally, laboratory data indicate that this technology is directly transferable to measurements on sheet metals and possibly other opaque web materials

Richard E. Russo

Papers

Optical energy conversion in crystalline nanowires

Method for elemental analysis in a production line

The dual beam picosecond continuum technique for measurement of short-time-scale transmission spectra

Laser Interrogation of Latent Vehicle Registration Number

Laser Ultrasonics at 20 m/s in the production environment and on a budget: from dream to reality