1 安徽建筑大学机械与电气工程学院，安徽 合肥 230601
2 中国科学技术大学工程科学学院，安徽 合肥 230027
3 安徽合力股份有限公司，安徽 合肥 230092
为了降低金属植入物与人体之间的排斥反应以及提高医用植入物材料的生物活性，本研究团队利用不同的表面加工方法对Zr55Cu30Ni5Al10表面进行改性，以制备天然骨的仿生微纳结构；然后将加工后的样品浸泡于模拟体液中，使其表面生成羟基磷灰石(HA)，研究不同加工方法下样品表面的润湿性以及HA沉积特性。结果表明：相较于传统的表面改性方法，纳秒激光结合飞秒激光的加工方法具有更加优异的加工效果，加工表面的水接触角由62°减小到26°，亲水性得到了大幅提升；纳秒激光结合飞秒激光加工的微纳结构不仅为HA的沉积提供了更多空间，而且其上的纳米颗粒有利于Ca2＋与的集聚，加速HA晶核的形成，从而生成均匀、稳定的HA沉积层，提高Zr55Cu30Ni5Al10表面HA的沉积效果。
中国激光
2022, 49(10): 1002604
Author Affiliations
Abstract
1 Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong,Sha Tin, Hong Kong, People’s Republic of China
2 CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027, People’s Republic of China
3 Chengdu Fine Optical Engineering Research Center, Chengdu 610041, People’s Republic of China
Several natural organism can change shape under external stimuli. These natural phenomena have inspired a vast amount of research on exploration and implementation of reconfigurable shape transformation. The Janus structure is a promising approach to achieve shape transformation based on its heterogeneous chemical or physical properties on opposite sides. However, the heterogeneity is generally realized by multi-step processing, different materials, and/or different processing parameters. Here, we present a simple and flexible method of producing pH-sensitive Janus microactuators from a single material, using the same laser printing parameters. These microactuators exhibit reversible structural deformations with large bending angles of ～31° and fast response (～0.2 s) by changing the pH value of the aqueous environment. Benefited from the high flexibility of the laser printing technique and the spatial arrangements, pillar heights, and bending directions of microactuators are readily controlled, enabling a variety of switchable ordered patterns and complex petal-like structures on flat surfaces and inside microchannels. Finally, we explore the potential applications of this method in information encryption/decryption and microtarget capturing. Supplementary material for this article is available online
micro actuator smart material pH hydrogel Janus structure laser printing International Journal of Extreme Manufacturing
2021, 3(2): 025001
Author Affiliations
Abstract
Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China
Microrobots-assisted drug delivery and surgery have been always in the spotlight and are highly anticipated to solve the challenges of cancer in situ treatment. These versatile small biomedical robots are expected to realize direct access to the tumor or disease site for precise treatment, which requires real-time and high-resolution in vivo tracking as feedback for the microrobots’ actuation and control. Among current biomedical imaging methods, photoacoustic imaging (PAI) is presenting its outstanding performances in the tracking of microrobots in the human body derived from its great advantages of excellent imaging resolution and contrast in deep tissue. In this review, we summarize the PAI techniques, imaging systems, and their biomedical applications in microrobots tracking in vitro and in vivo. From a robotic tracking perspective, we also provide some insight into the future of PAI technology in clinical applications.
photoacoustic imaging PACT OR-PAM microrobots tracking clinical applications Chinese Optics Letters
2021, 19(11): 111701
Author Affiliations
Abstract
1 City University of Hong Kong, Department of Biomedical Engineering, Kowloon, Hong Kong SAR, China
2 City University of Hong Kong, Shenzhen Research Institute, Shenzhen, China
Optical-resolution photoacoustic microscopy (OR-PAM) has been developed for anatomical, functional, and molecular imaging but usually requires multiple scanning for different contrasts. We present five-wavelength OR-PAM for simultaneous imaging of hemoglobin concentration, oxygen saturation, blood flow speed, and lymphatic vessels in single raster scanning. We develop a five-wavelength pulsed laser via stimulated Raman scattering. The five pulsed wavelengths, i.e., 532, 545, 558, 570, and 620 / 640 nm, are temporally separated by several hundreds of nanoseconds via different optical delays in fiber. Five photoacoustic images at these wavelengths are simultaneously acquired in a single scanning. The 532- and 620 / 640-nm wavelengths are used to image the blood vessels and dye-labeled lymphatic vessels. The blood flow speed is measured by a dual-pulse method. The oxygen saturation is calculated and compensated for by the Grüneisen-relaxation effect. In vivo imaging of hemoglobin concentration, oxygen saturation, blood flow speed, and lymphatic vessels is demonstrated in preclinical applications of cancer detection, lymphatic clearance monitoring, and functional brain imaging.
optical-resolution photoacoustic microscopy stimulated Raman scattering single-shot multi-contrast microscopy early cancer detection Advanced Photonics
2021, 3(1): 016002
1 安徽建筑大学机械与电气工程学院, 安徽 合肥 230601
2 中国科学技术大学工程科学学院, 安徽 合肥 230027
3 安徽省工程机械智能制造重点实验室, 安徽 合肥 230601
非晶合金材料具有独特、优异的性能,一直受到科技界的高度关注。随着高端装备制造领域的发展以及关键器件需求的增加,应用激光制造技术进行块体非晶合金构件成形、材料表面非晶强化与微细加工的研究备受关注。本文通过综合国内外文献资料,对非晶合金激光制造技术领域的有关研究状况进行了全面总结,分别介绍了非晶合金激光增材制造、非晶合金激光焊接、激光表面非晶化、激光熔覆非晶涂层和非晶合金激光烧蚀加工等方法与技术,阐述了相关技术的原理、研究现状、应用领域及发展趋势,最后对非晶合金激光制造技术进行了总结与展望。
激光技术 非晶合金 激光制造技术 增材制造 焊接 表面非晶化 熔覆 烧蚀加工
Author Affiliations
Abstract
1 Department of Biomedical Engineering, City University of Hong Kong, 999077 Hong Kong SAR, China
2 Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, 999077 Hong Kong SAR, China
3 City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
4 e-mail: apcslee@cityu.edu.hk
5 e-mail: lidawang@cityu.edu.hk
Distinguishing early-stage tumors from normal tissues is of great importance in cancer diagnosis. We report fiber-based confocal visible/near-infrared (NIR) optical-resolution photoacoustic microscopy that can image tumor microvasculature, oxygen saturation, and nanoprobes in a single scanning. We develop a cost-efficient single laser source that provides 532, 558, and 1064 nm pulsed light with sub-microseconds wavelength switching time. Via dual-fiber illumination, we can focus the three beams to the same point. The optical and acoustic foci are confocally aligned to optimize the sensitivity. The visible and NIR wavelengths enable simultaneous tumor imaging with three different contrast modes. Results show obvious angiogenesis, significantly elevated oxygen saturation, and accumulated nanoparticles in the tumor regions, which offer comprehensive information to detect the tumor. This approach also allows us to identify feeding and draining vessels of the tumor and thus to determine local oxygen extraction fraction. In the tumor region, the oxygen extraction fraction significantly decreases along with tumor growth, which can also assist in tumor detection and staging. Fiber-based confocal visible/NIR photoacoustic microscopy offers a new tool for early detection of cancer.
Photonics Research
2020, 8(12): 12001875
1 中国科学院 电子学研究所，北京 100190
2 中国科学院大学，北京 100190
提出了一种新型的应用于低压差线性稳压器(LDO)的斜坡软启动电路，其采用两路斜坡使能信号以及一路斜坡基准信号，消除了电源上电时产生的浪涌电流。该斜坡软启动电路已应用于一款LDO 中，并采用0.35 μm CMOS 工艺实现流片，其仅占LDO 有效面积的8.3%，消耗电流仅600 nA。仿真以及测试结果显示，采用该软启动电路之后，LDO 的上电浪涌电流得到有效抑制。LDO 在最差情况下的线性调整率为2.7 mV/V，负载调整率为0.064 mV/mA。
低压差线性稳压器 浪涌电流 斜坡使能 软启动 Low-Dropout Regulator in-rush current ramp-enabling soft-start 太赫兹科学与电子信息学报
2017, 15(1): 159
1 中国科学院 长春光学精密机械与物理研究所应用光学国家重点实验室，吉林 长春130033
2 中国科学院大学，北京 100049
从自适应光学应用的角度，对液晶波前校正器的过驱动矩阵的测量方法进行了系统研究。对量化级次和延迟时间进行了优化，最优量化级次为32级，最优延迟时间为14帧。最后，在延迟时间为14帧时，测量了液晶波前校正器的过驱动矩阵和终到位相矩阵，并对中等强度大气湍流进行了仿真校正，仿真计算结果与理论预期吻合得很好，表明测量方法可行。
液晶波前校正器 自适应光学 过驱动矩阵 终到位相矩阵 liquid crystal wavefront corrector adaptive optics overdriving matrix terminal phase matrix
