Research on the relationship between photothermal effect and wavelength of laser beam in gastric tumor

2021 ◽  
Author(s):  
Yang Zhao ◽  
Ao Teng ◽  
Jiahao Zeng ◽  
Xianlin Song
Keyword(s):  
Laser Beam ◽  
Gastric Tumor ◽  
Photothermal Effect ◽  
The Relationship

Local Microflow Control Using Photothermal Viscosity Distribution

2008 ◽  
Author(s):  
Jun Shimakawa ◽  
Masahiro Motosuke ◽  
Shinji Honami
Keyword(s):  
Laser Beam ◽  
Temperature Dependence ◽  
Temperature Rise ◽  
Local Heating ◽  
Velocity Variation ◽  
Dominant Factor ◽  
Photothermal Effect ◽  
Strong Temperature Dependence ◽  
Velocity Change ◽  
Micro Piv

A novel method of microflow control by locally heated liquid using an optical technique is described in this paper. Microflow control in the present study utilizes temperature dependence of the fluid property which becomes dominant in microscale. Since it is known that viscosity has strong temperature dependence, a local viscosity distribution has a potential to change microflow behavior. The purpose of the present study is to validate this concept of microflow control by using the local distribution of viscosity. In order to induce the temperature variation, photothermal effect is utilized. Absorption of a laser beam causes the local heating spot. This method has attractive features such as non-intrusive and high time- and spatial- resolution, and also has a possibility for a flexible flow control. We have developed an experimental system to irradiate focused laser beam on a flow in a microfluidic device and to measure velocity and temperature field of the microflow. The local temperature rise in microchannel flow is generated by a focused laser spot. During the laser irradiation, the velocity profile of the liquid flow in microchannel with 500 μm in width and 50 μm in height was measured by micro-PIV (Particle Image Velocimetry). The temperature measurement of the flow field was performed by micro-LIF (Laser-Induced Fluorescence). Around the heated area, the local increase of the flow velocity can be observed. It is found that the effect depends on the laser intensity and is independent of the bulk velocity. In addition, numerical simulation was conducted to identify the dominant factor causing the velocity change. As a simulation result, the cause of the velocity variation is the viscosity decrease corresponding to the temperature rise in fluid. Possibility of microflow control using the photothermal viscosity distribution is confirmed.

scholarly journals Enhancement of optical force acting on vesicles via the binding of gold nanoparticles

2019 ◽  
Vol 6 (5) ◽  
pp. 190293 ◽  
Author(s):  
Yumeki Tani ◽  
Takashi Kaneta
Keyword(s):  
Gold Nanoparticles ◽  
Light Scattering ◽  
Laser Beam ◽  
Binding Constant ◽  
Electrostatic Interactions ◽  
Propagation Direction ◽  
Optical Force ◽  
Surface Charges ◽  
Scattering Force ◽  
The Relationship

Here we found that gold nanoparticles (AuNPs) enhance the optical force acting on vesicles prepared from phospholipids via hydrophobic and electrostatic interactions. A laser beam was introduced into a cuvette filled with a suspension of vesicles and it accelerated them in its propagation direction via a scattering force. The addition of the AuNPs exponentially increased the velocity of the vesicles as their concentration increased, but polystyrene particles had no significant impact on velocity in the presence of AuNPs. To elucidate the mechanism of the increased velocity, the surface charges in the vesicles and the AuNPs were controlled; the surface charges of the vesicles were varied via the use of anionic, cationic and neutral phospholipids, whereas AuNPs with positive and negative charges were synthesized by coating with citrate ion and 4-dimethylaminopyridine, respectively. All vesicles increased the velocity at different degrees depending on the surface charge. The vesicles were accelerated more efficiently when their charges were opposite those of the AuNPs. These results suggested that hydrophobic and electrostatic interactions between the vesicles and the AuNPs enhanced the optical force. By accounting for the binding constant between the vesicles and the AuNPs, we proposed a model for the relationship between the concentration of the AuNPs and the velocity of the vesicles. Consequently, the increased velocity of the vesicles was attributed to the light scattering that was enhanced when AuNPs were adsorbed onto the vesicles.

The relationship between the individual components of YBCO films prepared by MOCVD with ArF laser beam irradiation

1992 ◽  
Vol 192 (1-2) ◽  
pp. 202-206 ◽  
Author(s):  
Hiroyuki Higa ◽  
Masaki Maeda ◽  
Ikuo Suzuki ◽  
Takahisa Ushida ◽  
Kazutoshi Higashiyama ◽  
...  
Keyword(s):  
Laser Beam ◽  
Beam Irradiation ◽  
Ybco Films ◽  
Laser Beam Irradiation ◽  
Arf Laser ◽  
The Individual ◽  
The Relationship

Influence of the Energy Density on the Porosity of Polyamide Parts in SLS Process

2012 ◽  
Vol 188 ◽  
pp. 400-405 ◽  
Author(s):  
Mirela Toth-Taşcău ◽  
Aurel Raduta ◽  
Dan Ioan Stoia ◽  
Cosmin Locovei
Keyword(s):  
Energy Density ◽  
Laser Beam ◽  
Process Parameters ◽  
Selective Laser Sintering ◽  
Main Process ◽  
Sintering Process ◽  
Part Quality ◽  
Part Structure ◽  
The Relationship ◽  
Recycled Material

This paper presents an experimental study about the influence of the Selective Laser Sintering process parameters on the surface and cross-section porosity of parts sintered in polyamide PA2200 material two times recycled. Using of recycled powder affects the part structure and mechanical properties. Therefore, the paper aims to develop a suitable strategy to improve the part structure by controlling the most important SLS process parameters. The main process parameter whose influence was studied is the energy density of the laser beam. Special sample was designed and prototyped using EOS P100 prototyping machine. Three repetition jobs with different energy density of the laser beam were performed. Scanning Electron Microscopy was used to analyze the surface morphology and microstructure of the sintered benchmark parts. The relationship between the SLS parameters and part quality will extend the use of PA2200 recycled material.

scholarly journals The Possibilities of Using the Terrestrial Scanning Data for Classification of Rocks in Limestone Mine “Czatkowice”

2015 ◽  
Vol 97 (1) ◽  
pp. 80-90
Author(s):  
Cezary Toś
Keyword(s):  
Laser Beam ◽  
Near Infrared ◽  
Spectrometric Analysis ◽  
Rock Classification ◽  
Rock Samples ◽  
Spectral Curves ◽  
Rock Formations ◽  
Beam Reflection ◽  
The Relationship

AbstractThis paper presents results of a research of potential utilisation of the intensity of laser beam reflection recorded by ground-based lasers, for an initial classification of rock formations within the Czatkowice Limestone Quarry. As part of the research, spectrometric analysis in visible (VIS), near-infrared (NIR) and Short-wavelength infrared (SWIR) bands was carried out for rock samples typical for the Czatkowice Quarry. Moreover, the rock samples were scanned using equipment working within different wavelengths. The reflected intensity of the laser beam recorded for each rock sample with several different scanners were analysed to assess their potential use for rock classification. The results of this analysis were then compared with spectral curves of each sample. The relationship between the intensity of the laser beam reflection and the spectral curves can be used for selection of most suitable scanner for rock classification.

Influence of Cu Surface Treatment on the Cu-Direct Via Hole Drilling Efficiency of PWBs

2007 ◽  
Author(s):  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Shogo Matsutani
Keyword(s):  
Laser Beam ◽  
Surface Treatment ◽  
Co2 Laser ◽  
Copper Foil ◽  
Copper Surface ◽  
Surface Shape ◽  
Hole Drilling ◽  
Black Oxide ◽  
Direct Drilling ◽  
The Relationship

This report describes the quality assessment of blind via holes (BVHs) of Printed Wiring Boards (PWBs) drilled by a CO2 laser using Cu-direct drilling. In the Cu-direct drilling method, the copper foil and the buildup layer are melted at the same time, and the surface is treated to increase the laser energy absorbed by the copper foil because an untreated copper surface reflects most of the 10.6-μm-wavelength CO2 laser beam. We used black-oxide and V-bond treatments as surface treatment. Previously, the only black-oxide treatment was paid attention to, but the new V-bond treatment is also investigated in this report. First, a straightforward method employing infrared thermography was proposed to determine the absorbance of the CO2 laser beam by the copper surface. Then, we used SEM to characterize the copper surfaces after surface treatment, and established the relationship between laser absorbance and surface shape. Subsequently, we observed the circumference of a point irradiated with the CO2 laser and explained melting processes were different from surface shape. Finally, we investigated the relationship between laser absorbance and BVH quality, and showed that a high absorbance improved BVH quality.

scholarly journals The Physicochemical Properties of Graphene Nanocomposites Influence the Anticancer Effect

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Wenbo Yang ◽  
Xiangyu Deng ◽  
Wei Huang ◽  
Xiangcheng Qing ◽  
Zengwu Shao
Keyword(s):  
Physicochemical Properties ◽  
Drug Loading ◽  
Chemical Properties ◽  
Photothermal Effect ◽  
Antitumor Effects ◽  
Graphene Nanocomposites ◽  
Graphene Nanocomposite ◽  
Systematic Understanding ◽  
Physical And Chemical ◽  
The Relationship

Graphene nanocomposite is an inorganic nanocomposite material, which has been widely used in the treatment of tumor at present due to its ability of drug loading, modifiability, photothermal effect, and photodynamic effect. However, the application of graphene nanocomposite is now limited due to the fact that the functions mentioned above are not well realized. This is mainly because people do not have a systematic understanding of the physical and chemical properties of GO nanomolecules, so that we cannot make full use of GO nanomolecules to make the most suitable materials for the use of medicine. Here, we are the first to discuss the influence of the physicochemical properties of graphene nanocomposite on the various functions related to their antitumor effects. The relationship between some important physicochemical properties of graphene nanocomposite such as diameter, shape, and surface chemistry and their functions related to antitumor effects was obtained through analysis, which provides evidence for the application of related materials in the future.

scholarly journals Laser Beam Pointing Stabilization Control through Disturbance Classification

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1946
Author(s):  
Hui Chang ◽  
Wen-Qi Ge ◽  
Hao-Cheng Wang ◽  
Hong Yuan ◽  
Zhong-Wei Fan
Keyword(s):  
Control System ◽  
Laser Beam ◽  
Control Strategies ◽  
Kinematic Model ◽  
Mechanical Vibration ◽  
External Disturbances ◽  
Stabilization Control ◽  
Laser Systems ◽  
Pointing Control ◽  
The Relationship

In laser systems, beam pointing usually drifts as a consequence of various disturbances, e.g., inherent drift, airflow, transmission medium variation, mechanical vibration, and elastic deformation. In this paper, we develop a laser beam pointing control system with Fast Steering Mirrors (FSMs) and Position Sensitive Devices (PSDs), which is capable of stabilizing both the position and angle of a laser beam. Specifically, using the ABCD matrix, we analyze the kinematic model governing the relationship between the rotation angles of two FSMs and the four degree-of-freedom (DOF) beam vector. Then, we design a Jacobian matrix feedback controller, which can be conveniently calibrated. Since disturbances vary significantly in terms of inconsistent physical characteristics and temporal patterns, great challenges are imposed to control strategies. In order to improve beam pointing control performance under a variety of disturbances, we propose a data-driven disturbance classification method by using a Recurrent Neural Network (RNN). The trained RNN model can classify the disturbance type in real time, and the corresponding type can be subsequently used to select suitable control parameters. This approach can realize the universality of the beam stabilization pointing system under various disturbances. Experiments on beam pointing control under several typical external disturbances are carried out to verify the effectiveness of the proposed control system.

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