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151.
Christian Schubert Vladimir Varlamov 《Mathematical Methods in the Applied Sciences》2011,34(13):1638-1648
We derive a number of new results on integrals of products of Airy functions, using various integral transform techniques. As an application, we deduce a compact integral representation, suitable for numerical integration, of the one‐loop photon propagator in a magnetic field in 2 + 1 dimensional scalar quantum electrodynamics. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
152.
A new approach based on microcantilevers is presented to detect infrared photons with high sensitivity. Infrared photons are measured by monitoring the amplitude change of a vibrating microcantilever under light pressure force.The irradiating light is modulated into sinusoidal and pulsed waves,and to be in-phase and anti-phase with the cantilever driving signal.A linear relationship between the amplitude change of the cantilever and the light power distributing on the cantilever was observed.Under a vacuum of 10-4 Pa,an infrared light power of 7.4 nW was detected with the cantilever.The in-phase and anti-phase modulation to the cantilever vibration using a pulsed light results in an enhanced response of the cantilever. 相似文献
153.
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155.
A series of Zn2+‐selective two‐photon fluorescent probes (AZnM1−AZnN) that had a wide range of dissociation constants (KdTP=8 nm‐ 12 μM ) were synthesized. These probes showed appreciable water solubility (>3 μM ), cell permeability, high photostability, pH insensitivity at pH>7, significant two‐photon action cross‐sections (86–110 GM) upon complexation with Zn2+, and can detect the Zn2+ ions in HeLa cells and in living tissue slices of rat hippocampal at a depth of >80 μm without mistargeting and photobleaching problems. These probes can potentially find application in the detection of various amounts of Zn2+ ions in live cells and intact tissues. 相似文献
156.
Dr. Valérie Alain‐Rizzo Delphine Drouin‐Kucma Cédric Rouxel Dr. Issa Samb Jérémy Bell Dr. Patrick Y. Toullec Dr. Véronique Michelet Dr. Isabelle Leray Dr. Mireille Blanchard‐Desce 《化学:亚洲杂志》2011,6(4):1080-1091
A series of rod‐shaped and related three‐branched push–pull derivatives containing phosphane oxide or phosphane sulfide (PO or PS)—as an electron‐withdrawing group conjugated to electron‐donating groups, such as amino or ether groups, with a conjugated rod consisting of arylene–vinylene or arylene–ethynylene building blocks—were prepared. These compounds were efficiently synthesized by a Grignard reaction followed by Sonogashira coupling. Their photophysical properties including absorption, emission, time‐resolved fluorescence, and two‐photon absorption (TPA) were investigated with special attention to structure–property relationships. These fluorophores show high fluorescence quantum yields and solvent‐dependent experiments reveal that efficient intramolecular charge transfer occurs upon excitation, thereby leading to highly polar excited states, the polarity of which can be significantly enhanced by playing on the end groups and conjugated linker. Rod‐shaped and related three‐branched systems show similar fluorescence properties in agreement with excitation localization on one of the push–pull branches. By using stronger electron donors or replacing the arylene–ethynylene linkers with an arylene–vinylene one induces significant redshifts of both the low‐energy one‐photon absorption and TPA bands. Interestingly, a major enhancement in TPA responses is observed, whereas OPA intensities are only weakly affected. Similarly, phosphane oxide derivatives show similar OPA responses than the corresponding sulfides but their TPA responses are significantly larger. Finally, the electronic coupling between dipolar branches promoted by common PO or PS acceptor moieties induces either slight enhancement of the TPA responses or broadening of the TPA band in the near infrared (NIR) region. Such behavior markedly contrasts with triphenylamine‐core‐mediated coupling, which gives evidence for the different types of interactions between branches. 相似文献
157.
Two‐photon microscopy (TPM) has become an indispensible tool in biology and medicine owing to the capability of imaging the intact tissue for a long period of time. To make it a versatile tool in biology, a variety of two‐photon probes for specific applications are needed. In this context, many research groups are developing two‐photon probes for various applications. In this Focus Review, we summarize recent results on model studies and selected examples of two‐photon probes that can detect intracellular free metal ions in live cells and tissues to provide a guideline for the design of useful two‐photon probes for various in vivo imaging applications. 相似文献
158.
研究了硅雪崩光电二极管(APD)对光通信波段近红外光子在不同频率、强度,以及APD 不同偏压下的双光子吸收效应(TPA)。通过实验详细测量了光频率从186.3 THz 到196.1 THz 变化时APD的TPA 效率,结果表明:随着入射光频率的不断增加,TPA 效率呈现出先增大、后减小的规律,并且在190.5 THz 附近达到最优效率。此外,在实验中观察到,随着入射光强的增大,TPA 效率也呈现出先增大、后减小的现象(此实验中的峰值光强度约10 mW)。 相似文献
159.
激光过程中真空态和单光子叠加态的量子特性 总被引:2,自引:2,他引:0
采用热纠缠态表象和有序算符内的积分技术,通过求解密度矩阵主方程,导出了真空态和单光子叠加态在激光过程中的Wigner函数和光子数分布的解析表达式。采用数值计算方法,给出了腔场的增益和衰减常数等参数取确定值时真空态和单光子叠加态的Wigner函数、负部体积和光子数分布的演化曲线。通过比较Wigner函数负值区域的变化,讨论了耗散过程对该量子态量子特性的影响。研究结果表明:随耗散过程进行,态的Wigner函数负值范围和负值深度都在逐渐减小,直至负值消失。 相似文献
160.
Superparamagnetic Twist‐Type Actuators with Shape‐Independent Magnetic Properties and Surface Functionalization for Advanced Biomedical Applications
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Christian Peters Olgaç Ergeneman Pedro D. Wendel García Michelle Müller Salvador Pané Bradley J. Nelson Christofer Hierold 《Advanced functional materials》2014,24(33):5269-5276
Directed nanoparticle self‐organization and two‐photon polymerization are combined to enable three‐dimensional soft‐magnetic microactuators with complex shapes and shape‐independent magnetic properties. Based on the proposed approach, single and double twist‐type swimming microrobots with programmed magnetic anisotropy are demonstrated, and their swimming properties in DI‐water are characterized. The fabricated devices are actuated using weak rotating magnetic fields and are capable of performing wobble‐free corkscrew propulsion. Single twist‐type actuators possess an increase in surface area in excess of 150% over helical actuators with similar feature size without compromising the forward velocity of over one body length per second. A generic and facile combination of glycine grafting and subsequent protein immobilization exploits the actuator's increased surface area, providing for a swimming microrobotic platform with enhanced load capacity desirable for future biomedical applications. Successful surface modification is confirmed by FITC fluorescence. 相似文献