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

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.

/pdf/zinc-oxide-nanostructures-growth-properties-and-applications-8d5hcz3lg8.pdf

Zinc oxide nanostructures: growth, properties and applications

Influence of the wavelength spectroscopy, laser induced plasma. The technique of laser induced breakdown spectroscopy, has demonstrated to be an effective tool for the qualitative and quantitative chemical analysis of solids. In this work we studied the influence of the wavelength and crater volu me on the emission signal. For this craters of 7 and 50 m of diameter were generated using a laser ablation microscope coupled with a spectrometer provided with an ICCD camera, in two different conditions of energy and for two different wavelengths (266 and 1064 n m). We found in this work that a greater efficiency in the removal of the material exists when we work with smaller wavelengths (UV). On the other hand when 1064 n m is employed a greater efficiency of excitation of the species in the plasma was found. We also studied the influence of the size of the crater on the intensity of emission of the plasma and it is related to the limits of detection.

Influencia d e la longitud de onda e n la e spe ctroscopia d e pla sma inducido por lá se r.

Ion Texturing of Amorphous Yttria‐Stabilized Zirconia to form a Template for YBa2Cu3O7 Deposition

La tecnica de espectroscopia de plasma inducida por laser, ha demostrado ser una herramienta efectiva para el analisis quimico cualitativo y cuantitativo de solidos. En este trabajo estudiamos la influencia de la longitud de onda del haz incidente sobre la senal de emision del plasma y sobre el tamano y volumen del crater generado en la superficie de la muestra. Para esto crateres de 7 y 50 m de diametro fueron generados empleando un microscopio de ablacion laser acoplado a un espectrofotometro provisto de una camara ICCD, en dos distintas condiciones de energia y para dos distintas longitudes de onda del haz incidente (266 y 1064 nm). Encontrando que existe una mayor eficiencia en la remocion del material cuando se trabaja con longitudes de ondas menores (UV). Por otro lado cuando se trabaja con una longitud de onda mayor en nuestro caso 1064 nm, se encuentra que existe una mayor eficiencia de excitacion de las especies en el plasma. Tambien se estudio la influencia del tamano del crater sobre la intensidad de emision del plasma y se relaciono esta con los limites de deteccion de las especies de interes.

/pdf/influencia-de-la-longitud-de-onda-en-la-espectroscopia-de-2pq6f3pkvo.pdf

Influencia de la longitud de onda en la espectroscopia de plasma inducido por láser.

Laser ablation has proven to be an important technology in an increasing number of applications. The fundamental mechanisms underlying laser ablation processes are quite complicated, and include laser interactions with the target as well as plasma development off the target. While substantial progress has been achieved in understanding laser ablation on the nanosecond and picosecond time scales, it remains a considerable challenge to elucidate the underlying mechanisms during femtosecond laser ablation. We present experimental observations of plasma development inside silica glass during single femtosecond laser pulse (100 fs, 800 nm) irradiation. Using a femtosecond time-resolved imaging technique, we measured the evolution of a laser-induced plasma inside the glass that has an electron number density on the order of 1019 cm-3. Additionally, we observed an air plasma outside the target which forms long before the explosion of a material vapor plume.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Femtosecond time-resolved studies of laser ablation

Photothermal deflection spectroscopy (PDS) has been successfully applied to the study of uranium oxide electrochemistry. A brief description of PDS and preliminary results that demonstrate the technique are presented. Concentration gradients formed at the electrode surface are measured by this technique. The gradients give insight into the reaction mechanisms. There is some evidence of the initiation of non-electrochemical dissolution of the uranium oxide. Optical absorption by the uranium oxide is measured by PDS and the first results indicate that the absorption of the surface does not change during electrochemical experiments. This result is contrary to literature measurements of bulk samples that indicate that the optical absorption should be strongly changing.

Richard E. Russo

Papers

Influencia d e la longitud de onda e n la e spe ctroscopia d e pla sma inducido por lá se r.

Ion Texturing of Amorphous Yttria‐Stabilized Zirconia to form a Template for YBa2Cu3O7 Deposition

Influencia de la longitud de onda en la espectroscopia de plasma inducido por láser.

Femtosecond time-resolved studies of laser ablation

Photothermal Deflection Spectroscopy Investigations of Uranium Electrochemistry