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Observational appearances of hairy black holes in the framework of gravitational decoupling

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Communications in Theoretical Physics 2024年第8期76卷 103-117页

作者： yizhi liang Xin Lyu Jun Tao Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu 610065China

We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition(WEC). Two types of thin illumination conditions are studied: spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, the lensing ring and the photon ring. Employing four types of astrophysical disk luminosity model,we investigate the appearance of halos and note that their luminosities do not superimpose when the source is on or beyond the innermost stable circular orbit.

关键词： hairy black hole shadow gravitational decoupling accretion disk

Free-moving-state microscopic imaging of cerebral oxygenation and hemodynamics with a photoacoustic fiberscope

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Light(Science & Applications) 2024年第1期13卷 33-46页

作者： Xiaoxuan Zhong yizhi liang Xiaoyu Wang Haoying Lan Xue Bai Long Jin Bai-Ou Guan Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou510632China

We report the development of a head-mounted photoacoustic fiberscope for cerebral imaging in a freely behaving *** 4.5-gram imaging probe has a 9-µm lateral resolution and 0.2-Hz frame rate over a 1.2-mm wide *** probe can continuously monitor cerebral oxygenation and hemodynamic responses at single-vessel resolution,showing significantly different cerebrovascular responses to external stimuli under anesthesia and in the freely moving *** example,when subjected to high-concentration CO_(2) respiration,enhanced oxygenation to compensate for hypercapnia can be visualized due to cerebral regulation in the freely moving *** studies exhibit significantly weakened compensation capabilities in obese *** new imaging modality can be used for investigating both normal and pathological cerebrovascular functions and shows great promise for studying cerebral activity,disorders and their treatments.

关键词： cerebral anesthesia moving

Block nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome to alleviate non-alcoholic steatohepatitis and live fibrosis

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China Medical Abstracts(Internal Medicine) 2021年第4期38卷 222-223页

作者： liang yizhi Dept Gastroenterol 2nd Affil Clin Med CollFujian Med UnivQuanzhou 362000

Objective To explore the role of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome in non-alcoholic steatohepatitis(NASH).Methods The liver tissue samples of 24 patients admitted to the Second Affiliated Hospital of Fujian Medical University were selected,including 12 NASH samples from liver biopsy and 12 normal liver tissues from the margin of hepatic hemangioma.

关键词： NLRP3 admitted inflam

Compact Dual-Frequency Fiber Laser Accelerometer With Sub-μg Resolution

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Photonic Sensors 2016年第2期6卷 115-120页

作者： Qian CAO Long JIN yizhi liang Linghao CHENG Bai-Ou GUAN Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of PhotonicsTechnology Jinan University Guangzhou 510632 China

We demonstrate a compact and high-resolution dual-polarization fiber laser accelerometer. A spring-mass like scheme is constructed by fixing a 10-gram proof mass on the laser cavity to transduce applied vibration into beat-frequency change. The loading is located at the intensity maximum of intracavity light to maximize the optical response. The detection limit reaches 107 ng/Hz1/2 at 200 Hz. The working bandwidth ranges from 60 Hz to 600 Hz.

关键词： Dual-frequency fiber lasers fiber Bragg grating photonic accelerometers

125 μm fiber based all-optical ultrasound probes for pulse-echo imaging

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Chinese Optics Letters 2019年第7期17卷 29-33页

作者： Yinlong Zhang yizhi liang Long Jin Baiou Guan Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics Technology Jinan University

All-optical ultrasound probes that contain a photoacoustically-based ultrasound generator paired with a photonic acoustic sensor provide a promising imaging modality for diagnostic and MRI-compatible ***, we demonstrate the fabrication of a fiber-based all-optical ultrasound probe and its applications in pulseecho ultrasound *** ultrasound generator is fabricated on a 125 μm multimode optical fiber by forming a light-absorbing multiwalled carbon nanotube(MWCNT)-polydimethylsiloxane(PDMS) composite coating on its distal end.A peak-to-peak acoustic pressure of 0.95 MPa was achieved with laser irradiation at 2.46 μJ by chemically functionalizing the fiber surface to enable a strong *** reception was performed by a fiber-laser ultrasound sensor that translates ultrasound pressure into differential lasing-frequency *** linearly scanning the probe, ex vivo two-and three-dimensional imaging of a segment of swine trachea was demonstrated by detecting the echo ultrasound signals and reconstructing the acoustic *** probe presents axial and lateral resolutions at 150 and 62 μm, *** small-sized, side-looking all-fiber ultrasound probe presents a promising approach for assembling an interventional endoscopy.

关键词： generator optical carbon was vivo its MPa

Flexible fiber-laser ultrasound sensor for multiscale photoacoustic imaging

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Opto-Electronic Advances 2021年第8期4卷 16-29页

作者： Bai-Ou Guan Long Jin Jun Ma yizhi liang Xue Bai Guangdong Provincial Key Laboratory of Fiber Optic Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 511443China

Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to *** PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound *** by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale *** simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound *** to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.

关键词： flexible ultrasound transducer fiber-laser ultrasound sensor multiscale photoacoustic imaging photoacoustic microscopy photoacoustic computed tomography

Low-Frequency Vibration Measurement by a Dual-Frequency DBR Fiber Laser

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Photonic Sensors 2017年第3期7卷 206-210页

作者： Bing ZHANG Linghao CHENG yizhi liang Long JIN Tuan GUO Bai-Ou GUAN Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics Technology Jinan University Guangzhou 510632 China

A dual-frequency distributed Bragg reflector （DBR） fiber laser based sensor is demonstrated for low-frequency vibration measurement through the Doppler effect. The response of the proposed sensor is quite linear and is much higher than that of a conventional accelerometer. The proposed sensor can work down to 1 Hz with high sensitivity. Therefore, the proposed sensor is very efficient in low-frequency vibration measurement.

关键词： Fiber laser sensors Doppler effect vibration measurement

基于外部光反馈的双偏振光纤激光器拍频相位噪声抑制

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中国激光 2016年第6期43卷 45-50页

作者：劳奕琴余贶琭程凌浩梁贻智梁浩关柏鸥暨南大学光子技术研究院广东广州510632 北京交通大学计算机与信息技术学院信息科学研究所北京100044

以光纤光栅作为反射镜,将双偏振光纤激光器的一小部分输出光经光纤延迟线延迟后再反馈回激光腔,降低了拍频信号的相位噪声。结果表明:反馈时间越长,噪声降低的幅度越大。以50m长的单模光纤作为延迟线,降低了双偏振光纤光栅激光器拍频信... 详细信息

以光纤光栅作为反射镜,将双偏振光纤激光器的一小部分输出光经光纤延迟线延迟后再反馈回激光腔,降低了拍频信号的相位噪声。结果表明:反馈时间越长,噪声降低的幅度越大。以50m长的单模光纤作为延迟线,降低了双偏振光纤光栅激光器拍频信号20dB以上的相位噪声,在10kHz偏移处相位噪声达到-92dBc/Hz的水平;光反馈的偏振态对外部光反馈系统的噪声抑制能力有影响,并对双偏振光纤激光器的拍频频率有微弱的调谐能力。

关键词：激光器双偏振光纤激光器相位噪声降噪

光纤光声显微成像的噪声特性分析与信噪比提升研究

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中国激光 2022年第15期49卷 93-100页

作者：黄杰梁贻智仲晓轩金龙关柏鸥暨南大学光子技术研究院广东省光纤传感与通信技术重点实验室广东广州510632

光纤光声成像技术利用光纤传感器来探测由激光脉冲在生物体内激发出的超声波,从而实现对目标组织成分的高对比度成像。光纤超声传感系统的噪声特性是成像信噪比的决定性因素之一,本研究团队详细分析了超声敏感元件——正交双频光纤激光... 详细信息

光纤光声成像技术利用光纤传感器来探测由激光脉冲在生物体内激发出的超声波,从而实现对目标组织成分的高对比度成像。光纤超声传感系统的噪声特性是成像信噪比的决定性因素之一,本研究团队详细分析了超声敏感元件——正交双频光纤激光器与光放大器、光电探测器及数据采集模块等各环节对噪声的贡献,同时分析了系统噪声、拍频信号功率和频率噪声与光功率(或者光电流)之间的关系。研究结果表明,通过光放大器提升注入光探测器的光功率能够显著提升光纤传感系统的信噪比,当注入光探测器的光功率达到10 mW以上时,拍频信号频率抖动的均方值可由74 kHz降低到44 kHz,在50 MHz带宽内提供的噪声等效声压由32.9 Pa降低到19.5 Pa,信噪比提升4.5 dB。进一步,本研究团队基于光纤超声传感器构造了光纤光声显微镜,并采用该显微镜对小鼠耳部血管进行活体成像,结果发现提升信号光功率能够显著增强图像的信噪比。

关键词：医用光学光声显微成像光纤超声传感器噪声特性