scholarly journals Accurate laser skin perforation technique aimed at promoting bleeding and reducing pain

2015 ◽  
Vol 08 (06) ◽  
pp. 1550029 ◽  
Author(s):  
Han-Chao Chang ◽  
Yu-Hsuan Lin ◽  
Kuo-Cheng Huang
Keyword(s):  
Laser Irradiation ◽  
Laser Energy ◽  
Skin Surface ◽  
Shallow Depth ◽  
Depth Of Field ◽  
Blood Collection ◽  
Promising Technique

Laser skin perforation is an effective and promising technique for use in blood collection. In this study, the relation between the perforation profile of skin and laser irradiation at various energies is discussed. Increasing laser energy does not uniformly expand the size and depth of a hole because the shallow depth of field (DOF) of the focused light primarily concentrates energy on the skin surface. In practice, the hole gradually transforms from a semielliptical shape to an upside-down avocado shape as the laser energy increases. This phenomenon can increase the amount of bleeding and reduce pain. The findings support the feasibility of developing an accurate laser skin perforation method.

scholarly journals Carbon-coated magnetic particles increase tissue temperatures after laser irradiation

2015 ◽  
Vol 08 (05) ◽  
pp. 1550018 ◽  
Author(s):  
Shupeng Liu ◽  
Na Chen ◽  
Fufei Pang ◽  
Zhengyi Chen ◽  
Tingyun Wang
Keyword(s):  
Laser Irradiation ◽  
Magnetic Particles ◽  
Laser Energy ◽  
Thermal Therapy ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fbg Sensor ◽  
Transmission Electron ◽  
Carbon Coated

Purpose: This work focused on the investigation the hyperthermia performance of the carbon-coated magnetic particles (CCMPs) in laser-induced hyperthermia. Materials and methods: We prepared CCMPs using the organic carbonization method, and then characterized them with transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). In order to evaluate their performance in hyperthermia, the CCMPs were tested in laser-induced thermal therapy (LITT) experiments, in which we employed a fully distributed fiber Bragg grating (FBG) sensor to profile the tissue's dynamic temperature change under laser irradiation in real time. Results: The sizes of prepared CCMPs were about several micrometers, and the LITT results show that the tissue injected with the CCMPs absorbed more laser energy, and its temperature increased faster than the contrast tissue without CCMPs. Conclusions: The CCMPs may be of great help in hyperthermia applications.

Coupled Thermal-Mechanical Analysis of CO2 Laser Irradiation on Fused Silica

2016 ◽  
Vol 1136 ◽  
pp. 531-536
Author(s):  
Run Qiang Li ◽  
Peng Yao ◽  
Hao Meng ◽  
Jun Wang ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Fused Silica ◽  
Depth Of Cut ◽  
Residual Tensile Stress ◽  
Thermally Induced

To grind fused silica in ductile mode, it was proposed to repair surface and subsurface micro cracks of fused silica by CO2 laser irradiation. However, excessive residual stress remains on the surface because the melt fused silica on the surface quenches in air. It causes the critical depth of cut for ductile grinding fused silica to be smaller than 0.2μm. To investigate the distribution of the residual stress and look for an optimal manner of irradiation to control residual tensile stress, a numerical model of was built for simulating the dynamic behavior of fused silica when irradiated by CO2 laser. Laser energy absorption, heat transmission, viscoelastic behavior of fused silica and thermally induced stress were considered in the numerical simulation. The results show how the residual stress is formed and distributed. We found that an appropriate control of the temperature field as a function of time and position in the laser process is the key to reduce the residual stress. Therefore, three kinds of processes were proposed to reduce residual tensile stress on the surface of fused silica introduced by laser irradiation. The residual stress distributions of these three processes were compared by numerical analysis to decide a better method of laser irradiation.

Er-Doping in Silicon by Pulsed Laser Irradiation

1993 ◽  
Vol 301 ◽  
Author(s):  
Kenshiro Nakashima
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Energy Density ◽  
Er Doping ◽  
Erbium Ions ◽  
State Regime ◽  
Er Doped ◽  
Pulsed Laser Irradiation

ABSTRACTErbium ions were successfully doped in silicon by pulsed laser irradiation above the threshold laser energy density. Photoluminescence peaks at 1.54, 1.59 and 1.64 µm from Er-optical centers were observed after annealing of Er-doped samples. The intensity of the 1.54 µm Er-emission band increased upon increase in the laser energy density, and then gradually decreased after reaching the maximum, due to the laser sputtering of the silicon substrate. Oxygen atoms, which were unintentionally codoped with Er-ions, were found to be distributed in the same region as in Er-ions, and were suggested to play roles to activate Er-optical centers. The maximum concentration of Er-ions doped in the solid state regime were estimated to be the order of 1018 cm−3 by the Rutherford backscattering measurements.

Electrical Properties of Solid Phase Crystallized Silicon Films

2001 ◽  
Vol 664 ◽  
Author(s):  
Tadashi Watanabe ◽  
Hajime Watakabe ◽  
Toshiyuki Sameshima
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Energy Density ◽  
Laser Irradiation ◽  
Carrier Mobility ◽  
Crystalline Silicon ◽  
Solid Phase ◽  
Laser Energy ◽  
Silicon Films ◽  
Laser Energy Density

ABSTRACTIn this study, the carrier mobility and density for solid phase crystallized (SPC) silicon films fabricated at 600 °C for 48 hours are analyzed by free carrier optical absorption. The carrier mobility is 40 cm2/Vs for SPC films doped with 6×1019-cm−3-phosphorus atoms. This analysis suggests the SPC films have fine crystalline grains closed to single crystalline silicon. In addition, initial carrier density was 3×1019 cm−3, which increased to 6×1019 cm−3by XeCl excimer laser irradiation of 500mJ/cm2. The inactivated regions in SPC films are reduced by laser irradiation. However, the electrical conductivity after laser irradiation for SPC films doped with 6×1018-cm−3-phosphorus atoms decreased from 3.3 to 0.018 S/cm as laser energy density increased to 500mJ/cm2. On the other hand, the electrical conductivity increased from 14.7 to 31.3 S/cm with similar increase of laser energy density after H2O vapor heat treatment at 260°C for 3 hours with 1.3 MPa. Furthermore, the characteristics of n-channel TFTs fabricated with initial SPC films as well as SPC films which was irradiated by laser at 425mJ/cm2 are also researched. The threshold voltage is decreased from 3.8 to 2.0 V by laser irradiation. Threshold voltages of both cases are decreased from 3.8 to 2.4 V for no-laser irradiation and from 2.0 to 0.8 V for laser irradiation, after H2O vapor heat treatment at 310°C for 1 hour with 9.0MPa. Based on the above trial, the defect reduction method combining laser irradiation and H2O vapor heat treatment has proved to be very effective for SPC films and SPC TFTs.

Low-Energy, Pulsed-Laser Irradiation of Amorphous Silicon: Melting and Resolidification at Two Fronts

1984 ◽  
Vol 35 ◽  
Author(s):  
W. Sinke ◽  
F.W. Saris
Keyword(s):  
Amorphous Silicon ◽  
Laser Irradiation ◽  
Surface Segregation ◽  
Crystalline Silicon ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Surface Region ◽  
Low Energy ◽  
Double Peak Structure ◽  
Pulsed Laser Irradiation

ABSTRACTAfter low-energy pulsed-laser irradiation of Cu-implanted silicon, a double-peak structure is observed in the Cu concentration profile, which results from the occurrence of two melts. From Cu surface segregation we calculate the depth of the surface melt. Cu segregation near the position of the amorphous-crystalline interface gives evidence for a self-propagating melt, moving from the surface region towards the crystalline substrate. Measurements of As-redistribution and of sheet resistance as a function of laser energy density in As-implanted silicon are consistent with the crystallization model which is derived from the effects as observed in Cu-implanted silicon.The results imply a large difference in melting temperature, heat conductivity and heat of melting between amorphous silicon and crystalline silicon.

Processing Grinding-Damaged Silicon Wafers by High-Frequency Nano-Second Laser Irradiation

2009 ◽  
Vol 76-78 ◽  
pp. 451-456
Author(s):  
Ji Wang Yan ◽  
Sei Ya Muto ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Energy Density ◽  
Amorphous Silicon ◽  
Laser Irradiation ◽  
High Frequency ◽  
Laser Energy ◽  
Large Diameter ◽  
Silicon Wafers ◽  
Density Level ◽  
Transmission Electron ◽  
Beam Center

Ultraprecision diamond-ground silicon wafers were irradiated by a high-frequency nanosecond pulsed Nd:YAG laser equipped on a four-axis numerically controlled stage. The resulting specimens were characterized using a white-light interferometer, a micro-Raman spectroscope and a transmission electron microscope. The results indicate that around the laser beam center where the laser energy density is sufficiently high, the grinding-induced amorphous silicon was completely transformed into the single-crystal structure. The optimum conditions for one- and two-dimensional overlapping irradiation were experimentally obtained for processing large-diameter silicon wafers. It was found that the energy density level required for completely removing the dislocations is higher than that for recrystallizing the amorphous silicon. After laser irradiation, the surface unevenness has been remarkably flattened.

scholarly journals A Study on Laser Enhanced Electrodeposition for Preparation Fe-Ni Alloy

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3560
Author(s):  
Zhaoyang Zhang ◽  
Yucheng Wu ◽  
Anbin Wang ◽  
Kun Xu ◽  
Xueren Dai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Morphology ◽  
Laser Irradiation ◽  
Laser Energy ◽  
New Method ◽  
Micro Structure ◽  
Alloy Electrodeposition ◽  
Ni Alloy

In this paper, a method of laser enhanced electrodeposition is used for preparation of Fe-Ni alloy, which exhibits a significant advantage in fabrication of alloys. The effect of laser energy on Fe-Ni alloy electrodeposition by the manner of reciprocating scanning is studied. Results show that laser irradiation can improve the surface morphology, micro-structure and mechanical properties of Fe-Ni alloy. The results are useful for the development of a new method to synthesize Fe-Ni alloy with better properties.

A Mismatch Detection Method Based on Affine Transformation for Stereo Light Microscopy Stereo Matching

2017 ◽  
Vol 31 (05) ◽  
pp. 1750013
Author(s):  
Shengli Fan ◽  
Mei Yu ◽  
Gangyi Jiang ◽  
Yigang Wang ◽  
Hao Jiang ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Affine Transformation ◽  
Stereo Matching ◽  
Detection Method ◽  
Shallow Depth ◽  
Depth Of Field ◽  
Constraint Condition ◽  
Mismatch Detection ◽  
Matching Pair ◽  
Microscopy Images

For the light microscopy images that have the characteristics of shallow depth of field, serious distortion and poor resolution, mismatch is a ubiquitous phenomenon. The paper presents a mismatch detection method for the stereo light microscopy stereo matching. Affine transformation matrix and matching constraint condition are calibrated by the calibration board which has the precision solid dots and the motorized stage. Bias vector of affine transformation of each matching pair is taken as the criteria to apply mismatch detection. The experimental results show that the method can detect more mismatching pairs and preserve more matching pairs than the traditional RANSAC method and the epipolar rectification method.

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