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光声成像技术在生物医学中的研究进展 总被引:1,自引:0,他引:1
简要介绍了生物医学中的光声成像技术机理,总结报道了国内外几种典型的光声成像方法和光声图像重建算法的发展历程及其最新进展,指出该技术是一种很有应用前景的医学检测方法。 相似文献
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目的:应用激光诱导荧光技术检测光动力治疗大鼠牙周炎过程中荧光光谱强度,分析治疗的最佳激光功率和治疗时间.方法:把20只大鼠上颌第一磨牙用细菌结扎线建立牙周病模型,随机分成5组,每只大鼠左侧进行治疗,右侧不进行治疗(阴性对照).每组大鼠使用亚甲基蓝光敏剂,在激光波长660nm特定功率下进行光动力治疗.利用光学多通道分析仪采集治疗过程中产生的荧光光谱强度,并观察治疗后各组的细菌菌落数.结果:使用激光功率250mW,连续照射时间4min时,产生的荧光光谱强度最大.治疗后检测发现该组细菌菌落数减少最多,验证了在该条件下治疗达到了最优效果.结论:激光诱导荧光法监测光动力治疗组织内光敏剂荧光变化可有效地反映光敏剂含量的变化,对于了解光动力反应的进行情况以及预测治疗效果具有一定指导意义,为制定光动力治疗慢性牙周炎方案提供理论依据. 相似文献
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金纳米微粒的光学性质及其在生物成像和光热疗法中的应用 总被引:2,自引:0,他引:2
作为生物探针,纳米微粒以其独特的光学性质,易控的表面化学能力,在基于生物成像和诊断的分子生物学和医学领域中引起越来越广泛的关注.贵金属,尤其是金纳米微粒,由于其表面等离子体共振(SPR)等强吸收和发光特性,在生物组织成像,癌症的诊断和治疗中存在着巨大的应用前景.结合配体的金纳米微粒能够特异性地标记癌症细胞上的受体,并提供特定分子的特有信息,进行生物成像和癌症检测.另外,金纳米微粒能够有效地吸收光能量进行局部加热,导致蛋白质变性,并致细胞死亡.主要回顾各种不同尺寸和形状的金纳米微粒的光学特性,以及选择性标记的金纳米微粒在生物成像,癌症诊断和光热疗法中的研究进展. 相似文献
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摘要用单层人类正常皮肤成纤维细胞(HSFs)作为细胞模型,研究高强度激光束边缘低强度激光的光生物凋节作用。分别用1064nm和532nm脉冲激光对24组培养的HSFs单层细胞进行照射。研究发现,高脉冲能量的照射导致较低存活率和较大的损伤半径。对接受1064nm照射的HSFs,100mJ照射组和150mJ照射组在照射24h和48h后检测发现显著促进增殖;而对532nm照射的HSFs,100mJ照射组在照射24h和48h后检测发现受到显著抑制增殖。这些结果表明。高强度激光束边缘低强度激光存在光生物调节作用,这可能是影响外科激光的长期效应的重要因素。 相似文献
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The growth of epitaxial films on featured substrates has an important device application in junction-confinement, double hetero-structure
light emitting diodes. These devices are presently grown by a liquid phase epitaxy process but growth by metalorganic chemical
vapor deposition is desirable because of MOCVD's superior surface quality, uniformity, and throughput. This paper describes
the effect of growth parameters on AlGaAs films deposited by atmospheric-pressure MOCVD into substrate holes typically made
in the fabrication of junction-confinement LEDs. MOCVD growth replicates the substrate features; it does not give a planar
surface over the holes. The behavior of epitaxy filling into holes is strongly dependent on growth temperature and total gas
flow and largely independent of substrate misorientation and the thickness of the layer grown. Wet-etched holes formed (ll0)-oriented
V-groove and dovetail-groove features on the hole circumference. Faceting of the MOCVD growth was seen on the wall with the
(111)A feature while smooth growth was seen on the etched (111)B surface.
Deceased. 相似文献
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本文对基于带间级联结构和谐振腔结构的中红外发光二极管进行了仿真和设计。在传统带间级联发光二极管的基础上,从器件外部引入分布布拉格反射镜(DBR)谐振腔结构,形成谐振腔带间级联发光二极管。对谐振腔参数进行仿真优化,包括DBR周期数、谐振腔的腔长、有源区在谐振腔中的位置等。结果表明,使用单周期ZnS/Ge DBR作为谐振腔上反射镜的器件输出功率最大,有源区置于谐振腔内部电场强度波峰处时,器件的输出功率最大,三级谐振腔带间级联LED器件的输出功率与55级无谐振腔器件输出功率相当,其光束发散角的半峰全宽可以从92度减小到52度。结合已生长的5级带间级联LED器件的测试结果,增加谐振腔结构后的仿真结果表明,峰值波长的辐射强度增强11.7倍,积分辐射强度增强5.43倍,光谱的半峰宽变窄6.45倍。 相似文献
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本文采用步进应力的试验方法设计了一个针对GaAs红外发光二极管的可靠性加速寿命的研究方案.这种方法主要是把步进应力和恒定应力两种方法相结合,用此来评估GaAs红外发光二极管的可靠度;然后总结除了GaAs红外发光二极管这种光电器件的寿命分布形式和失效模式. 相似文献
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A CdHgTe resonant cavity light emitting diode (RCLED) is proposed as a new infrared emitter. The device is prepared by molecular
beam epitaxy on a CdZnTe substrate. A 10.5 periods Bragg mirror is first deposited. The cavity material is made of Cd0.75Hg0.25Te and contains a wide well (50 nm) designed to emit at 3.2 μm. The last three periods of the mirror are n-type doped while
the cavity material is covered by a thin p-type CdZnTe layer. A gold layer closes the cavity, serving as the second mirror
of a Fabry-Perot cavity tuned around 3.18 urn. It also provides an ohmic contact to the p-region. Under forward bias, the
emission spectrum displays a narrow peak (8 meV full width at half maximum) corresponding to the cavity resonance. The position
and linewidth of this line are independent of temperature. The directivity of the diode is also improved with respect to a
conventional emitter, in agreement with theoretical expectations. Taking advantage of the spectral properties of the RCLED
a new multispectral device has been fabricated. 相似文献
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The enhancement of the light output of an embedded photonic crystal light emitting diode is investigated based on the finite-difference time-domain modeling.The embedded photonic crystal(PC) lattice type,multi-layer embedded PC,distance between the multiple quantum well and the embedded PC are studied.It is found that the embedded one dimensional PC can act as well as embedded two dimensional PCs.The emitted light flux in the up direction can be increased by a new kind of multi-layer embedded PC.Also,we ... 相似文献