检索结果-南通市图书馆

Mechanisms,Techniques and Applications of photoacoustic effect in Semiconductors

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 1994年第2期 78-87页

作者：张淑仪王兆球程建春陆悦生沈耀春 Laboratory of Modern Acoustics Nanjing 210008 Nanjing University PRC

Photoaooustic technique, as a nondestructive, noncontact and noranvasive method, has been widely used to characterize properties, structures and parameters of materials. This paper describes briefly the studies on photoacoustic phenomena in semiconductor materials and devices including the mechanisms, techniques and applications of photoacoustic effect in semiconductors

关键词： photoacoustic effect semiconductor laminated imaging spectroscopy.

High-resolution photoacoustic microscope for rat brain imaging in vivo

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2010年第6期8卷 609-611页

作者：杨孝全蔡鑫 Konstantin Maslov 汪立宏骆清铭 Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and Technology Optical Imaging Laboratory Department of Biomedical EngineeringWashington University in Saint LouisSaint Louis63130-4899USA

A reflection-mode photoacoustic microscope（PAM） for rat brain imaging in vivo is constructed.A pulsed laser is used as an excitation source,and a focused ultrasound transducer is adopted to collect the photoacoustic *** scanning is applied to acquire three-dimensional（3D） *** obtained measurements of the lateral and axial resolutions of the microscope are 45 and 15μm,*** imaging depth in the chicken breast tissue is 3.1 mm at a signal-to-noise ratio（SNR） of 20 dB without any signal *** imaging speed is 30 A-line/*** results in vivo demonstrate the capability of 3D imaging of the brain vessels of the rat after removing the skull.

关键词： Acoustic microscopes Laser excitation photoacoustic effect photoacoustic microscopy Pulsed laser applications Pulsed lasers Signal to noise ratio Ultrasonic transducers

photoacoustic spectroscopy for fast and sensitive ammonia detection

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2007年第11期5卷 677-679页

作者：张望武智瑛于清旭 School of Physics and Optoelectronic Technology Dalian University of Technology Dalian 116023 Informational Engineering Department Environmental Management College of China Qinhuangdao 066004

A photoacoustic （PA） spectrometer with H-type first longitudinal resonant cells for ammonia detection is developed. A new PA cell structure is designed to accelerate the drift velocity of the sample gas near the cell surface, so that the short response time at the flow rate of 100 seem （standard cubic centimeter per minute） is achieved. The response time of 5 min and detection limit of 0.86 ppbv is reached for ammonia concentration measurement with a Teflon polytetrafluoroethylene （PTFE） cell. Further improvement could be expected when using a brass cell with a high quality Teflon fluorinated ethylene propylene （FEP） coating.

关键词： Ammonia Flow rate photoacoustic effect Polytetrafluoroethylenes

Feasibility of photoacoustic tomography for ophthalmology

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2007年第8期5卷 475-476页

作者：卢涛宋智源苏翼雄张帆姚建铨 Institute of Lasers and Optoelectronics College of Precision Instrument and Opto-Electronics Engineering Tianjin University

For the eyeball composed of membrane and liquid, the contrast of ultrasound imaging is not high due to its small variance in acoustic impedance. As a new imaging modality, photoacoustic tomography combines the advantages of pure optical and ultrasonic imaging together and can provide high resolution, high contrast images. In this paper, the feasibility of photoacoustic tomography for ophthalmology is studied experimentally. A Q-switched Nd：YAG pulsed laser with 7-ns pulse width is used to generate photoacoustic signal of a porcine eyeball in vitro. The two-dimensional （2D） optical absorption image of the entire eyeball is reconstructed by time-domain spherical back projection algorithm. The imaging results agree well with the histological structure of the eyeball and show a high imaging contrast.

关键词： Acoustic impedance Algorithms Laser pulses Light absorption Ophthalmology photoacoustic effect Q switched lasers Two dimensional Ultrasonic imaging

Indocyanine green loaded graphene oxide for high-e±cient photoacoustic tumor therapy

在线全文

学校读者我要写书评

暂无评论

Journal of Innovative Optical Health Sciences 2016年第4期9卷 47-54页

作者： Baoyun Yan Huan Qin MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science College of Biophotonics South China Normal University Guangzhou 510631 P.R.China

photoacoustic therapy,using the photoacoustic efect of agents for selectively kling tumor cells,has shown pronising for treat ing *** of high optical absorption probes can help to effectively improve the photoacoustic ther apy ***,we report a novel high-absorpt:ion photoacoustic probe that is composed of indocyanine green(ICG)and gr aphene oxide(GO),entitled GO-ICG,for photoacoustic ther *** attached ICG with narrow absorption spectral profile has strong optical absorption in the infrared *** absorption spectrum of the GO-ICG solution reveals that the GO-ICG particles exhibited a 10-fold higher absorbance at 780 nm(its peak absorbance)as compared with ***,ICG's fluorescence is quenched by GO via fuorescence resonance energy *** a result,GO-ICG can high efficiently convert the absorbed light energy to acoustic wave under pulsed laser *** further demonstrate that GO-ICG can produce stronger photoacoustic wave than the GO and ICG ***,we conjugate this contrast agent with integrin 0。As mono dlonal antibody to molecularly target the U87-MG human glioblastoma cells for selective tumor cell ***,our results testify that the photoacoustic therapy eficiency of GO-ICG is higher than the existing photoacoustic therapy *** work demonstrates that GO-ICG is a high efficiency photo-acoustic therapy *** novel photoacoustic probe is likely to be an available candidate for tumor therapy.

关键词： photoacoustic therapy photoacoustic effect tumor therapy

photoacoustic image reconstruction based on Bayesian compressive sensing algorithm

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2011年第6期9卷 44-47页

作者：孙明健冯乃章沈毅李建刚马立勇伍政华 Department of Control Science and Engineering Harbin Institute of Technology

The photoacoustic tomography （PAT） method, based on compressive sensing （CS） theory, requires that, for the CS reconstruction, the desired image should have a sparse representation in a known transform domain. However, the sparsity of photoacoustic signals is destroyed because noises always exist. Therefore, the original sparse signal cannot be effectively recovered using the general reconstruction algorithm. In this study, Bayesian compressive sensing （BCS） is employed to obtain highly sparse representations of photoacoustic images based on a set of noisy CS measurements. Results of simulation demonstrate that the BCS-reconstructed image can achieve superior performance than other state-of-the-art CS-reconstruction algorithms.

关键词： Image reconstruction Laser diagnostics photoacoustic effect

Noninvasive photoacoustic measurement of absorption coefficient using internal light irradiation of cylindrical diffusing fiber

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2017年第5期13卷 367-371页

作者：彭东青朱莉莉李志芳李晖 School of Science Jimei University Key Laboratory of Optoelectronic Science and Technology for Medicine Ministry of Education of China College of Photonic and Electronic Engineering Fujian Normal University

Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber(CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.

关键词： Imaging techniques Irradiation Light absorption photoacoustic effect

Adaptive multi-sample-based photoacoustic tomography with imaging quality optimization

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2015年第6期13卷 31-35页

作者：王育昕袁杰都思丹刘晓峻徐冠王学鼎 School of Electronic Science and Engineering Nanjing University School of Physics Nanjing University Department of Radiology University of Michigan

The energy of light exposed on human skin is compulsively limited for safety reasons which affects the power of photoacoustic （PA） signal and its signal-to-noise ratio （SNR） level. Thus, the final reconstructed PA image quality is degraded. This Letter proposes an adaptive multi-sample-based approach to enhance the SNR of PA signals and in addition, detailed information in rebuilt PA images that used to be buried in the noise can be distinguished. Both ex vivo and in vivo experiments are conducted to validate the effectiveness of our proposed method which provides its potential value in clinical trials.

关键词： Image quality photoacoustic effect

Ultraefficient thermoacoustic conversion through a split ring resonator

在线全文

学校读者我要写书评

暂无评论

Advanced Photonics 2020年第3期2卷 69-77页

作者： Lu Lan Yueming Li Tiffany Yang-Tran Ying Jiang Yingchun Cao Ji-Xin Cheng Boston University Department of Biomedical EngineeringBostonMassachusettsUnited States Boston University Department of Mechanical EngineeringBostonMassachusettsUnited States Boston University Department of Electrical and Computer EngineeringBostonMassachusettsUnited States Boston University Photonics Center BostonMassachusettsUnited States

Microwaves,which have a∼10-cm wavelength,can penetrate deeper into tissue than photons,heralding exciting deep tissue applications such as modulation or imaging via the thermoacoustic *** conversion efficiency is however very low,even with an exogenous contrast *** break this low-conversion limit,using a split ring resonator to effectively collect and confine the microwaves into a submillimeter hot spot for ultrasound emission and achieve a conversion efficiency over 2000 times higher than other reported thermoacoustic contrast ***,the frequency of emitted ultrasound can be precisely tuned and multiplexed by modulation of the microwave *** performance is inaccessible by a piezoelectric-based transducer or a photoacoustic emitter and,therefore,split ring resonators open up new opportunities to study the frequency response of cells in ultrasonic *** applications in deep tissue localization,a split ring resonator can be used as a wireless,battery-free ultrasound beacon placed under a breast phantom.

关键词： thermoacoustic effect metamaterial photoacoustic effect split ring resonator ultrasound