Prostate cancer is one of the most common types of cancer among men. The mortality rate for this ... more Prostate cancer is one of the most common types of cancer among men. The mortality rate for this disease can be dramatically reduced if it can be diagnosed in its early stages. Raman spectroscopy is one of the optical techniques which can provide fingerprints of a disease in terms of its molecular composition which changes due to the onset of
2004 IEEE International Conference on Systems, Man and Cybernetics (IEEE Cat. No.04CH37583), 2004
Robotic control application on remote surgery has initiated an increasing interest recently as a ... more Robotic control application on remote surgery has initiated an increasing interest recently as a result of the rapid development of the communication technology and multi-sensory integration. Raman spectroscopy can provide detailed information on molecular composition and it enables the detection of sample pathological changes in a non-destructive manner. It is particularly useful for in vivo tissue analysis. A feasible objective is to create a real-time approach of sample analysis using a Raman spectrometer directly mounted at the end-effector of medical robot to enhance the remote robot surgery. In order to extract intrinsic Raman spectrum, the impact of background spectrum needs to be excluded at first. Signal to noise ratio (SNR) can be improved by filtering techniques and the data normalization can be conducted by standard normal variate (SNV). Principal component analysis (PCA) is proposed for sample identification. PCA is used for dimension reduction so that significant signatures for different types of samples are indicated by dominant eigenvectors from the correspondent covariance matrix. Eventually different principal components are selected for cluster separation. By principal component analysis and control oriented identification, various samples can be distinguished in terns of intrinsic Raman spectrum. In this study, PCA identifies tissues from distinct clusters of different organs. A systematic approach is then formulated for sample identification via Raman spectroscopy.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1992
ion mixing occurs when an ion beam of a few hundred keV bombards an interface under the surface. ... more ion mixing occurs when an ion beam of a few hundred keV bombards an interface under the surface. Low-energy ion mixing arises when an ion beam of a few keV bombards an interface near the surface during, e.g., sputter depth profiling and low-energy ion-assisted deposition. At low temperatures, the rate of both high-and low-energy ion mixing can be influenced by thermodynamic parameters, such as the heat of mixing and the cohesive energy of solids. These effects are demonstrated by ion mixing experiments using metallic bilayers consisting of high-atomic-number elements. A model of diffusion in thermal spikes is used to explain this similarity. Low-energy ion mixing can also he strongly affected by surface diffusion and the morphol(~gic~~l stability of thin films. These effects are illustrated using results obtained from sputter depth profiling of Ag/Ni, Ag/Fe, and Ag/Ti hilayers at elevated temperatures.
ABSTRACTUtilizing plasma source molecular beam epitaxy (PSMBE), we have grown epitaxial InxAl1-xN... more ABSTRACTUtilizing plasma source molecular beam epitaxy (PSMBE), we have grown epitaxial InxAl1-xN films on (0001) sapphire substrates; the indium concentration, x, varied from 0 to 1. The atomic force microscopy of the films reveals characteristic surface patterns of nanometer scale. The feature size distribution is determined by the film composition and thickness. Both absorption and reflection spectra of the films have additional peaks below the fundamental absorption threshold. These peaks cannot be associated with N vacancies or any other known crystal defects and impurities. We attribute the peaks to electron confinement in the hillocks of the lateral structure by the strong electric field of piezoelectric and spontaneous polarization that is characteristic to nitride semiconductor compounds. The calculated values of the electron energy levels are in good agreement with the spectroscopic data; moreover, the electron confinement model explains the observed temperature dependence...
Proceedings of the 2005 IEEE International Frequency Control Symposium and Exposition, 2005., 2005
We are developing a highly sensitive surface acoustic wave (SAW) sensor system for biomedical and... more We are developing a highly sensitive surface acoustic wave (SAW) sensor system for biomedical and industrial applications. One of the key components of such a system is the signal read-out unit based on digital phase detection, which is needed to quantitatively determine tiny mass change on the sensor. To find a method that produces the highest precision, we have compared
ABSTRACT The InN, InAlN, and AlN films with thickness ranging from 100 to 8000 Å have been grown ... more ABSTRACT The InN, InAlN, and AlN films with thickness ranging from 100 to 8000 Å have been grown on (0001) sapphire substrates, utilizing plasma source molecular beam epitaxy (PSMBE), we have grown films. All the obtained films are epitaxial with no phase segregation, as shown by high resolution X-ray diffraction scans. Characteristic surface pattern of large number of 10-nanometer scale hillocks is revealed by the atomic force microscopy; the size distribution of these hillocks depends of the film composition and thickness, as well as on the buffer layer thickness in the case of In-containing films. Associated with the hillocks, additional absorption peaks are detected far below the fundamental absorption threshold. Counterintuitive temperature dependences of these peaks can be explained in the framework of the model of electron localization near the hillock tips due to built-in electric field
Two sets of epitaxial Ni_1-xCux films of 50 nm thickness were prepared on Cu(100)/Si(100) substra... more Two sets of epitaxial Ni_1-xCux films of 50 nm thickness were prepared on Cu(100)/Si(100) substrates at room temperature using MBE deposition. For one set of films x was constant for each film, ranging from 0.1 to 0.4. For the second set the Cu content varied through the film thickness between x = 0 and 0.4. Alloy composition was controlled by
Frontiers in Optics 2008/Laser Science XXIV/Plasmonics and Metamaterials/Optical Fabrication and Testing, 2008
ABSTRACT The concept of the “smart” sensor has been proposed. We investigated protein attachment ... more ABSTRACT The concept of the “smart” sensor has been proposed. We investigated protein attachment to the diffraction grating surface area. The same diffraction grating was used for surface plasmon sensors both SPP and LRSSP structures.
We have developed a super compact optical fluorescence spectrometer. Our innovative design combin... more We have developed a super compact optical fluorescence spectrometer. Our innovative design combines advantages of guided wave planar optics and free-space microoptics. This innovation allows for miniaturization that is not achievable with pure planar or pure free-space optics. A prototype device has volume of its optical part below 1cm3. The spectrometer covers 450nm-650nm spectral range, and provides spectral resolution of
Studies in health technology and informatics, 2008
A redesigned motion control system for the medical robot Aesop allows automating and programming ... more A redesigned motion control system for the medical robot Aesop allows automating and programming its movements. An IR eye tracking system has been integrated with this control interface to implement an intelligent, autonomous eye gaze-based laparoscopic positioning system. A laparoscopic camera held by Aesop can be moved based on the data from the eye tracking interface to keep the user's gaze point region at the center of a video feedback monitor. This system setup provides autonomous camera control that works around the surgeon, providing an optimal robotic camera platform.
Conference Proceedings. 2nd International IEEE EMBS Conference on Neural Engineering, 2005., 2005
Abstract Serially received multiplexed pixels of an image are decoded and scanned on the probes... more Abstract Serially received multiplexed pixels of an image are decoded and scanned on the probes array to stimulate the retina to reproduce the image. This paper presents a retinal stimulator (RS), which needs only six interface wires irrespective of array size. RS decodes the time-...
Proceedings of SPIE - The International Society for Optical Engineering, 2009
AlN films deposited on sapphire substrates were damaged by single UV nanosecond (at 248 nm) and I... more AlN films deposited on sapphire substrates were damaged by single UV nanosecond (at 248 nm) and IR femtosecond (at 775 nm) laser pulses in air at normal pressure. The films had high (27-35 atomic %) concentration of oxygen introduced into thin surface layer (5-10 nm thickness). We measured damage threshold and studied morphology of the damage sites with atomic force and Nomarski optical microscopes with the objective to determine a correlation between damage processes and oxygen content. The damage produced by nanosecond pulses was accompanied by significant thermal effects with evident signatures of melting, chemical modification of the film surface, and specific redistribution of micro-defect rings around the damage spots. The nanosecond-damage threshold exhibited pronounced increase with increase of the oxygen content. In contrast to that, the femtosecond pulses produced damage without any signs of thermal, thermo-mechanical or chemical effects. No correlation between femtosecond-damage threshold and oxygen content as well as presence of defects within the laser-damage spot was found. We discuss the influence of the oxygen contamination on film properties and related mechanisms responsible for the specific damage effects and morphology of the damage sites observed in the experiments.
Proceedings of SPIE - The International Society for Optical Engineering, 2009
We present results of comparative study of laser-induced ablation of AlN films with variable cont... more We present results of comparative study of laser-induced ablation of AlN films with variable content of oxygen as a surface-doping element. The films deposited on sapphire substrate were ablated by a single nanosecond pulse at wavelength 248 nm, and by a single femtosecond pulse at wavelength 775 nm in air at normal pressure. Ablation craters were inspected by AFM and
Prostate cancer is one of the most common types of cancer among men. The mortality rate for this ... more Prostate cancer is one of the most common types of cancer among men. The mortality rate for this disease can be dramatically reduced if it can be diagnosed in its early stages. Raman spectroscopy is one of the optical techniques which can provide fingerprints of a disease in terms of its molecular composition which changes due to the onset of
2004 IEEE International Conference on Systems, Man and Cybernetics (IEEE Cat. No.04CH37583), 2004
Robotic control application on remote surgery has initiated an increasing interest recently as a ... more Robotic control application on remote surgery has initiated an increasing interest recently as a result of the rapid development of the communication technology and multi-sensory integration. Raman spectroscopy can provide detailed information on molecular composition and it enables the detection of sample pathological changes in a non-destructive manner. It is particularly useful for in vivo tissue analysis. A feasible objective is to create a real-time approach of sample analysis using a Raman spectrometer directly mounted at the end-effector of medical robot to enhance the remote robot surgery. In order to extract intrinsic Raman spectrum, the impact of background spectrum needs to be excluded at first. Signal to noise ratio (SNR) can be improved by filtering techniques and the data normalization can be conducted by standard normal variate (SNV). Principal component analysis (PCA) is proposed for sample identification. PCA is used for dimension reduction so that significant signatures for different types of samples are indicated by dominant eigenvectors from the correspondent covariance matrix. Eventually different principal components are selected for cluster separation. By principal component analysis and control oriented identification, various samples can be distinguished in terns of intrinsic Raman spectrum. In this study, PCA identifies tissues from distinct clusters of different organs. A systematic approach is then formulated for sample identification via Raman spectroscopy.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1992
ion mixing occurs when an ion beam of a few hundred keV bombards an interface under the surface. ... more ion mixing occurs when an ion beam of a few hundred keV bombards an interface under the surface. Low-energy ion mixing arises when an ion beam of a few keV bombards an interface near the surface during, e.g., sputter depth profiling and low-energy ion-assisted deposition. At low temperatures, the rate of both high-and low-energy ion mixing can be influenced by thermodynamic parameters, such as the heat of mixing and the cohesive energy of solids. These effects are demonstrated by ion mixing experiments using metallic bilayers consisting of high-atomic-number elements. A model of diffusion in thermal spikes is used to explain this similarity. Low-energy ion mixing can also he strongly affected by surface diffusion and the morphol(~gic~~l stability of thin films. These effects are illustrated using results obtained from sputter depth profiling of Ag/Ni, Ag/Fe, and Ag/Ti hilayers at elevated temperatures.
ABSTRACTUtilizing plasma source molecular beam epitaxy (PSMBE), we have grown epitaxial InxAl1-xN... more ABSTRACTUtilizing plasma source molecular beam epitaxy (PSMBE), we have grown epitaxial InxAl1-xN films on (0001) sapphire substrates; the indium concentration, x, varied from 0 to 1. The atomic force microscopy of the films reveals characteristic surface patterns of nanometer scale. The feature size distribution is determined by the film composition and thickness. Both absorption and reflection spectra of the films have additional peaks below the fundamental absorption threshold. These peaks cannot be associated with N vacancies or any other known crystal defects and impurities. We attribute the peaks to electron confinement in the hillocks of the lateral structure by the strong electric field of piezoelectric and spontaneous polarization that is characteristic to nitride semiconductor compounds. The calculated values of the electron energy levels are in good agreement with the spectroscopic data; moreover, the electron confinement model explains the observed temperature dependence...
Proceedings of the 2005 IEEE International Frequency Control Symposium and Exposition, 2005., 2005
We are developing a highly sensitive surface acoustic wave (SAW) sensor system for biomedical and... more We are developing a highly sensitive surface acoustic wave (SAW) sensor system for biomedical and industrial applications. One of the key components of such a system is the signal read-out unit based on digital phase detection, which is needed to quantitatively determine tiny mass change on the sensor. To find a method that produces the highest precision, we have compared
ABSTRACT The InN, InAlN, and AlN films with thickness ranging from 100 to 8000 Å have been grown ... more ABSTRACT The InN, InAlN, and AlN films with thickness ranging from 100 to 8000 Å have been grown on (0001) sapphire substrates, utilizing plasma source molecular beam epitaxy (PSMBE), we have grown films. All the obtained films are epitaxial with no phase segregation, as shown by high resolution X-ray diffraction scans. Characteristic surface pattern of large number of 10-nanometer scale hillocks is revealed by the atomic force microscopy; the size distribution of these hillocks depends of the film composition and thickness, as well as on the buffer layer thickness in the case of In-containing films. Associated with the hillocks, additional absorption peaks are detected far below the fundamental absorption threshold. Counterintuitive temperature dependences of these peaks can be explained in the framework of the model of electron localization near the hillock tips due to built-in electric field
Two sets of epitaxial Ni_1-xCux films of 50 nm thickness were prepared on Cu(100)/Si(100) substra... more Two sets of epitaxial Ni_1-xCux films of 50 nm thickness were prepared on Cu(100)/Si(100) substrates at room temperature using MBE deposition. For one set of films x was constant for each film, ranging from 0.1 to 0.4. For the second set the Cu content varied through the film thickness between x = 0 and 0.4. Alloy composition was controlled by
Frontiers in Optics 2008/Laser Science XXIV/Plasmonics and Metamaterials/Optical Fabrication and Testing, 2008
ABSTRACT The concept of the “smart” sensor has been proposed. We investigated protein attachment ... more ABSTRACT The concept of the “smart” sensor has been proposed. We investigated protein attachment to the diffraction grating surface area. The same diffraction grating was used for surface plasmon sensors both SPP and LRSSP structures.
We have developed a super compact optical fluorescence spectrometer. Our innovative design combin... more We have developed a super compact optical fluorescence spectrometer. Our innovative design combines advantages of guided wave planar optics and free-space microoptics. This innovation allows for miniaturization that is not achievable with pure planar or pure free-space optics. A prototype device has volume of its optical part below 1cm3. The spectrometer covers 450nm-650nm spectral range, and provides spectral resolution of
Studies in health technology and informatics, 2008
A redesigned motion control system for the medical robot Aesop allows automating and programming ... more A redesigned motion control system for the medical robot Aesop allows automating and programming its movements. An IR eye tracking system has been integrated with this control interface to implement an intelligent, autonomous eye gaze-based laparoscopic positioning system. A laparoscopic camera held by Aesop can be moved based on the data from the eye tracking interface to keep the user's gaze point region at the center of a video feedback monitor. This system setup provides autonomous camera control that works around the surgeon, providing an optimal robotic camera platform.
Conference Proceedings. 2nd International IEEE EMBS Conference on Neural Engineering, 2005., 2005
Abstract Serially received multiplexed pixels of an image are decoded and scanned on the probes... more Abstract Serially received multiplexed pixels of an image are decoded and scanned on the probes array to stimulate the retina to reproduce the image. This paper presents a retinal stimulator (RS), which needs only six interface wires irrespective of array size. RS decodes the time-...
Proceedings of SPIE - The International Society for Optical Engineering, 2009
AlN films deposited on sapphire substrates were damaged by single UV nanosecond (at 248 nm) and I... more AlN films deposited on sapphire substrates were damaged by single UV nanosecond (at 248 nm) and IR femtosecond (at 775 nm) laser pulses in air at normal pressure. The films had high (27-35 atomic %) concentration of oxygen introduced into thin surface layer (5-10 nm thickness). We measured damage threshold and studied morphology of the damage sites with atomic force and Nomarski optical microscopes with the objective to determine a correlation between damage processes and oxygen content. The damage produced by nanosecond pulses was accompanied by significant thermal effects with evident signatures of melting, chemical modification of the film surface, and specific redistribution of micro-defect rings around the damage spots. The nanosecond-damage threshold exhibited pronounced increase with increase of the oxygen content. In contrast to that, the femtosecond pulses produced damage without any signs of thermal, thermo-mechanical or chemical effects. No correlation between femtosecond-damage threshold and oxygen content as well as presence of defects within the laser-damage spot was found. We discuss the influence of the oxygen contamination on film properties and related mechanisms responsible for the specific damage effects and morphology of the damage sites observed in the experiments.
Proceedings of SPIE - The International Society for Optical Engineering, 2009
We present results of comparative study of laser-induced ablation of AlN films with variable cont... more We present results of comparative study of laser-induced ablation of AlN films with variable content of oxygen as a surface-doping element. The films deposited on sapphire substrate were ablated by a single nanosecond pulse at wavelength 248 nm, and by a single femtosecond pulse at wavelength 775 nm in air at normal pressure. Ablation craters were inspected by AFM and
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