다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

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 richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light-emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state-of-the-art in this emerging field.

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Graphene photonics and optoelectronics

Research into terahertz technology is now receiving increasing attention around the world, and devices exploiting this waveband are set to become increasingly important in a very diverse range of applications. Here, an overview of the status of the technology, its uses and its future prospects are presented.

Cutting-edge terahertz technology

Terahertz spectroscopy systems use far-infrared radiation to extract molecular spectral information in an otherwise inaccessible portion of the electromagnetic spectrum. Materials research is an essential component of modern terahertz systems: novel, higher-power terahertz sources rely heavily on new materials such as quantum cascade structures. At the same time, terahertz spectroscopy and imaging provide a powerful tool for the characterization of a broad range of materials, including semiconductors and biomolecules.

Materials for terahertz science and technology

As THz waves interact with vibration and rotation transitions of organic molecules, they can be used to identify specific molecules based on their spectral features. In this way, THz technology can be used as a complement to other electromagnetic spectroscopy methods, such as visible and infrared. As THz photons have lower energy, they are unable to ionize biological samples under normal conditions. This makes THz spectroscopy an ideal tool for the examination of active biomedical samples. Due to the complexity of working with biological samples, biological applications are considered a mid- to long-term goal of THz research.

THz Technology in Bio and Medical Applications

Unlike polarization control of optical waves, lossless control over the polarization of broadband terahertz waves remained challenging. We recently found that the polarization of terahertz waves generated from gas plasma excited by femtosecond fundamental pulse (ω) and its second harmonic (2ω) could be coherently controlled by changing the relative phase between the ω and 2ω pulses. In particular, when the ω and 2ω pulses are both circularly polarized (or close to it), the photo-excited electrons exhibit different trajectories as the relative phase between the two optical pulses changes, and subsequently terahertz polarization angle can be controlled arbitrarily through the relative phase while the intensity of the emitted terahertz wave is kept constant. This new finding may enable fast terahertz wave modulation and coherent control of nonlinear responses excited by intense terahertz waves with controllable polarization.

Coherent Polarization Control of THz Waves Generated from Asymmetrically Ionized Gases

We present an investigation of coherent mid-infrared pulse measurement system using free-space electro-optic sampling technique. A series of nonlinear materials are investigated for the nonresonant optical rectification and electro-optic sampling for the generation and detection, respectively. A sampling bandwidth up to 40 THz is achieved. For spectroscopic application we present THz field radiation by optically excited coherent phonons in the mid-infrared frequency range. We compare the THz radiation under extremely different excitation conditions. The comparison shows the THz radiation property of the resonantly driven phonons in the surface field layer. Furthermore we investigate the coherent reststrahl band reflectivity in the time domain. Unexpectedly strong oscillations are observed near the longitudinal-optical phonon frequency. This THz waveform is discussed with the reststrahl band dispersion of the reflectivity.

Mid-infrared THz beam sensors: exploration and application for phonon spectroscopy

Generation of terahertz (THz) radiation was observed in epitaxial VO 2 films grown on R- and C-cut sapphire substrates above and below the metal-insulator phase transition temperature. Polarization analysis of the emitted THz radiation reveals strong in-plane anisotropy of the conductive phase of VO 2 which is not observed for insulating phase, generation efficiency increases up to 30 times after phase transition. Properties of generated THz radiation in VO 2 are defined by the displacement photocurrent at the film-air and film-substrate interfaces.

Generation of terahertz radiation in thin vanadium dioxide films undergoing metal-insulator phase transition

Three of four states of matter: solid, gas, and plasma have been used for THz wave generation for decades. However, the demonstration of THz wave generation from liquid sources was conspicuously absent, especially from liquid water, due to its infamously strong absorption characteristics in the THz regime. Liquids have a high molecular density and a relatively low ionization threshold, meaning that light over a certain area will interact with many more molecules than an equivalent cross-section of gases and will generate more electrons. This makes liquids potential candidates for the generation of THz waves.

Xi-Cheng Zhang

Papers

THz Technology in Bio and Medical Applications

Coherent Polarization Control of THz Waves Generated from Asymmetrically Ionized Gases

Mid-infrared THz beam sensors: exploration and application for phonon spectroscopy

Generation of terahertz radiation in thin vanadium dioxide films undergoing metal-insulator phase transition

THz Aqueous Photonics and Beyond