Functional imaging for the understanding of higher brain function of human (human brain mapping) is now moving into the mainstream of neuroscience. This article reviews the present status of major imaging modalities, PET and functional MRI, with regard to their principles, advantages and limitations. Future perspective of this newly emerged field is discussed.
We have developed the underground visualization methods using latest geophysical prospecting. The purpose of this study is to visualize shallow and deep underground structure using electronic and computer science. We have studied 1) Development of the radar reflection method, 2) Construction of the geophysical survey system around shallow sea area, 3) Construction of the three dimensional survey system.
Neutrinos and other cosmic-ray particles are invisible to us. However, these particles are detected, or visualized, by specialized detectors. The law of the elementary particals and their interactions and the nature of the Universe is studied by observing these particles. In this article, the present status of the neutrino and cosmic ray observations and the implications of these observations are reviewed.
We first reviewed the new progress of wavelet analysis in experimental fluid mechanics. As multiscale identification techniques, we then presented two new applications of wavelets in experimental fluid mechanics. Finally, we state several perspectives and point out where new methods need to be developed in order to improve our understanding of turbulent structure.
In this paper the wavelet-based image compression technique is applied to PIV processing for reducing noise in images and reducing the physical storage. To determine the effect of the choice of the wavelet bases, the standard PIV images are compressed by some known wavelet families, Daubechies, Coifman, and baylkin families. It was found that high order wavelet bases provides good compression performance for compressing PIV Images, because they have good frequency localization that in turn increases the energy compaction. The reconstructed PIV image with lower compression ratio may emphasize particle edges at a relatively high spatial resolution, and the reconstructed PIV image with higher compression ratio may display the large-scale motion of particles and may deduce noisy. In this study, higher compression ratio, from 25% to 6.25%, can be realized without losing significant flow information in PIV processing. It can say that the wavelet image compression technique is effective in PIV system.
To evaluate coherent structures in the dimension of time and scale, a new procedure based on the multiresolution analysis and multiresolution auto-correlation analysis is developed in this paper. By analyzing u-and v-components of fluctuating velocity, the coherent structure and its scales can be identified when larger amplitude fluctuation and stronger auto-correlation are appeared at same wavelet level. For a turbulent jet at position of x/d=6, the larger coherent structures with frequency 39Hz can be deduced around times 0.29, 0.53, 0.6 and 0.67s. This also represent the passing of eddies through the shear layer and concentration of the energy of the flow at these instants.
The circular jet which issues along the outer wall and in the longitudinal direction of the cylinder has been investigated in this paper. Especially, attention is focussed on the unsteady structure of the flow field where the wall jet separates at the down stream location far form the nozzle exit. In order to reveal this unsteady property, the wavelet analysis was used besides the analysis through the ordinary flatness factor and intermittency factor. In addition to some wavelet correlations, the wavelet intermittency was newly introduced. Through these wavelet analytic methods the properties of separated flow has been clarified.
Stripe structure in turbulent boundary layer has been clearly visualized by discrete wavelet transform based on the shear stress data using MEMS(Micro-Electro-Mechanical-Systems). The chip is designed and fabricated by surface micromachining technology. The characteristics of high shear stress streaks were described with statistics. Physical quantities associated with the high shear stress streaks such as their length, width and peak shear stress level, were obtained.
In the previous report, a method to extract circular pattern has been proposed. The method utilizes geometrical property of circle, and can detect circular patterns very fast (100 particles within 1 second). The method was applied to particle image, but the method did not consider overlapped particle. In this paper, the method further improved to be able to count particle which are overlapped. The performance of the new method is examined by applying images of crowded particles groups that contain various size of particles.
A detailed experiment investigation of rebound trajectory of impinging particle on a flat plate was carried out using Ar+ laser and a camera. The jet velocity was 6.9 m/s and 15 m/s, and three kinds of glass beads of 30, 58 and 100 μm in diameter were used. The photographs of particle motion trajectory show that the impingement and the rebound depend on the momentum of particle: and the secondimpingement depends on the particle diameter and the entrainment velocity of environment air. The particle motion near the plate shows a rounded trajectory in radial direction by air flow along the wall.
Coherent Doppler lidar provide important data for investigating turbulent transport and exchange processes in the lower troposphere with high vertical and time resolution.. TIT (Tohoku Institute of Technology) and CRL(Communication Research Laboratories) have been developing the 2-μm in coherent lidar system. In this paper, we discuss the conceptual design of lidar system and also the algorithm for data analysis in order to visualize wind data. current status of our coherent Doppler lidar.
Total Ozone Mapping Spectrometer (TOMS) was first launched on board the NIMBUS 7 satellite in November 1978. TOMS measured the global distribution of total ozone every one day. This first TOMS was a very long lived instrument which continued its observation for about 14.5 years through May 6, 1993. The name of TOMS became well known when the ozone hole, severe ozone depletion during the Antarctic spring, was discovered. The TOMS data showed clearly not only the extent of ozone hole area over the Antarctica but also the development of ozone hole with time since the early 80's. After the NIMBUS 7/TOMS stopping its operation, Meteor 3/TOMS, ADEOS/TOMS succeeded the total ozone observation from the space and now the Earth Probe/TOMS has been operated in the orbit. Daily total ozone mapping data by TOMS is very useful not only to study the atmospheric ozone and also to learn the dynamic behavior of the Earth's atmosphere.
Clouds and aerosols play important role in radiative process of the atmosphere, and the observation of three dimentional distributions of clouds and aerosols are required in the studies of climate change. Lidars are useful tools for visualizing the distributions of clouds and aerosols. Vertical profile of clouds and aerosols has been continuously observed at NIES in Tsukuba with a compact Me scattering lidar. Statistical analysis of the distributions of clouds and aerosols is being conducted. Asian dust (Kosa) events are sometimes recorded in the continuous observation, and the data is used in the modeling study on transportation of Asian dust. Observation of the planetary boundary layer using three lidars has been conducted in Jakarta, Indonesia. The results reveal a typical diurnal variation with a sea/land breeze circulation. Planned three-dimensional observation of global distribution of clouds and aerosols with the NASDA's space borne lidar (ELISE) is also discussed.
This paper will present some examples of data visualization in the field of atmospheric science. It is essentially important to visualize the spatial feature of distribution of atmospheric compositions such as ozone, aerosol, and so on for the research of global environmental problems. We have developed some visualization tools to analyze various kinds of satellite data and applied them for the analysis of ozone destruction in the stratosphere. An example of visualization of the Polar Stratospheric Cloud (PSC) over the Arctic observed with a satellite sensor will be presented. The Improved Limb Atmospheric Spectrometer (ILAS) observed many PSC events during the winter of 1997, when there was a significant decrease in Arctic ozone. More than a hundred PSC profiles were identified over the Arctic during the period.
The Improved Limb Atmospheric Spectrometer (ILAS) was a satellite sensor developed by Global Environment Division, the Environment Agency of Japan, for monitoring the ozone layer. ILAS was onboard the ADEOS (Advanced Earth Observing Satellite) "MIDORI" satellite which was launched on August 17, 1996 by the National Space Development Agency of Japan (NASDA). ILAS measured about 6700 vertical profiles of O3, HNO3, NO2, N2O, CH4, and H2O in the stratosphere both in the Northern and the Southern Hemispheres from November 1996 to June 1997. It provided valuable observational data for investigating the mechanism of ozone loss in high latitude stratosphere. Substantial ozone loss was found from the ILAS O3 data, which were taken in early spring in 1997 in the northern high latitude region. Simultaneously, frequent occurrence of Polar Stratospheric Clouds (PSCs) was observed.
Interferometric Monitor for Greenhouse gases (IMG) aboard Advanced Earth Observing Satellite (ADEOS) is a Fourier Transform type Spectrometer (FTS) which was developed by Japanese Ministry of International Trade and Industry (MITI) for measuring greenhouse gases in the atmosphere. It had been operated for about 7 months from November 1996 to the end of the satellite life time in June 1997. During the operational period IMG has measured over 138000 terrestrial thermal emission spectra of which the signal to nose ratio is sufficient for retrieving atmospheric parameters such as temperature and gas concentrations. Preliminary results from the IMG retrieval analyses showed that there were some high concentration areas of methane and carbon monoxide in the northern hemisphere and around tropical region, respectively. In these analyses a cloud screening and correction method which was based on the initially retrieved temperature profile analysis was used to retrieve the gas concentrations. However, the results might be strongly affected by cloud contamination effects, because the loud screening method was not effective enough for the data observed over high latitude regions. It is very important to validate these retrieved data using directly sampled gas concentration data, and also important is to develop a more effective cloud detection method using satellite imagery data such as OCTS data.
The measurements of temperarure and velocity distributions near a heated rotating disc were conducted using the Laser Induced Fluorescence (LIF) technique and the Particle Image Velocimetry (PIV). We found that vortices appeared on the disc in the natural convection dominant region and were classified into three types (Wave, Normal, and Plume type). Then we investigated the characteristics of these three types of vorteces. First, we found that these three types of vortices have nearly the same influence on heat conduction, because temperature gradient in the vertical direction near the wall are almost the same. On the other hand, the maximum velocity in the vertical direction is different from each other. Moreover, turbulent heat flux in the vertical direction of each type has a different value, where Wave type has the minimum and Plume type has the maximum. Hence these three types of vortices are thought to have different influence on the heat transfer.
High-pressure diesel fuel sprays and their internal structure are observed using a novel visualization technique based on laser-induced fluorescence (LIF). A synchronization system is developed to control the timings of fuel injection, laser emission and image acquisition so as to capture spray images at an arbitrary stage of their developing process. Greatly magnified images of fluorescence dye, Rhodamine B, are taken and the internal velocities of fuel spray are measured by PIV in the core of the spray. The results show that branch-like structures are clearly visualized and diesel spray droplets exist along them. Fuel spray droplets are rapidly decelerated from about 300 m/s to 3-6 m/s at a time 4 ms after the injection.
A two-layer, salt-stratified system destabihized and mixed by lateral heating and cooling is considered The laser induced fluoresomw to pique exhibits that time pe plumes travel along the inteif and they are alignedin the spanwise direction with a constant spacing. The existenoe of phumes is also predicted by spectral method. The dimensionless period of oscillation is found to be inversely proporticnal to the 0.5 exponent of the thermal Raylegh number for various parameters.
Discrete wavelets transform is widely used for the wave and image analysis. On the other side, Major of the conventional image handling is based on the storing the snap shots of graphics image data. These types of image handling methodology greatly depend on the development of hardware. With the development of the modern software and hardware technologies, the demand for high quality and high speed image processing is increasing for various industrial applications. In the present paper, we propose a new methodology of image data handling technique by discrete wavelets transform.
Field theory is applied to the computer graphics. The key idea is that image data is regarded as a field potential or source density. After the governing equation of computer graphics is derived, the finite differences, finite elements and Green's function methods are applied to solve the governing equations. This approach makes it possible to compress the graphics image data without losing most of the original information. Moreover, wavelet transform is available to generate the compressed image data including rich original graphics information. We demonstrate that the computer graphics images can be compressed by wavelets as well as image calculus. Further, we try to carry out the twice/double image compression by combining both of the wavelets and image calculus methods.
One of the distinguished properties of the discrete wavelets transform is that the major dominant factors can be extracted from the data. We have applied this property to the data compression and reducing the noise data. In the present paper, we have tried to shrink and enlarge the color image data in static as well as dynamic states by means of the vector wavelets transform. Key idea is that the color image data are represented in terms of the 3-dimensional vector data by corresponding the red, green and blue orthogonal components of the image to the 3-dimensional orthogonal x, y and z components. Several examples demonstrate the usefulness of our new method to work out the graphical communication tools.
This paper tries to recover a color graphics image having original resolution from a lowresolution image by means of an inverse approach. A discrete wavelet transform makes it possible to concentrate an entire image information onto the vicinities of a mother wavelet spectrum region so that it is possible to obtain a rich information compressed image. Our problem is how to recover an image having original resolution from the rich information compressed image. One is a wavelets transform method, and the other is an inverse approach. The former recovers an image with finite accuracy, but the latter is capable of recovering an image with higher accuracy. In this paper, we describe a way of constructing a rich information compressed image having low resolution, and that an inverse approach is able to recover a better image than those of the conventional wavelets transform method.
A new concept is introduced to extract the essential and distinct characteristics of images. A key idea is to introduce the eigen patterns, which represents the characteristics of images independent of the resolutions and position of images on the screen. The eigen pattern of an image is obtained by projecting the pixel information in x-y screen coordinate to a red, green and blue coordinate systems. Thereby, this projection removes the location, angle and size information in a screen, and extracts the essential characteristics of the target image. We apply the notion of eigen patterns to human faces identification/synthesis with high resolution. As a result, we have succeeded in recovering and identifying the 10 human faces.
In this paper, as an application of wavelets to synthetic aperture radar (SAR) remote sensing, a wavelet-based method to reduce speckle is presented. SAR images are inherently accompanied with speckle due to coherent processing used to produce the images. Speckle in SAR images is regarded as a troublesome noise disturbing image interpretation. The presented method is based on an idea that speckle may be suppressed by reducing the amplitude of the pixels in detail images (i.e., the wavelet coefficients) in each wavelet subspace. In the method, edges are preserved by releasing the amplitude reduction around them. Experimental results with actual SAR images demonstrate the effectiveness of the method. In the latter half of the paper, the relation between the smoothing effect of the method and the parameters is fully investigated. The smoothing effect is dependent on the wavelet subspace level and the degree of amplitude reduction of wavelet coefficients. Using this relation, an approach for speckle reduction with texture preservation is derived.
The conventional two dimensional wavelet transformation is not effective to extract arc and circle features form the imagery data. In order to enhance the capability in an effective manner, a polar coordinates of representation of wavelet transformations is proposed. The proposed paper describes the proposed method of the aforementioned polar coordinates of representation of wavelet transformations followed by examples of the application of the method for circle feature extraction from Earth observation satellite data of OCTS onboard ADEOS satellite. The results are compared to the conventional two dimensional wavelet transfromations.
Difference between two particle surfaces has been clearly obtained with Fourier-wavelet transform method even though the two particles are located in two dimensional different place. The method consists of three steps, the first is to acquire the difference between two particle surface image data in Fourier space. The second is to operate wavelet transform to the difference image data transformed with inverse Fourier. Finally, the decomposed data with each space-frequency level are acquired by inverse wavelet transform and its multiresolution analysis. The high frequency image shows location and size of the difference. This technique contributes to automation of particles classification.
In this paper, we propose a method for image processing by applying vector field theory and vector wavelets transform. The process of this method consists of making vector data from pixel value and multi resolution analysis for the vector data. The method is applied to measurement of concrete cracks and discrimination of road condition. The method can reduce the quantity of information about spots and texture of illumination, resulting in exactly extracted cracks. With the method, we can decide the surface condition of road quantitatively.
When a shock wave propagating in a tube arrives at its exit, an impulsive wave is emitted toward the surrounding. The objective of this work is to investigate the usefulness of passive control using tube exit modifications for increasing the strength of impulsive wave. As a result, a suitable choice of tube exit modifications was suggested from a viewpoint of augmentation of the impulsive wave.
The objective of this study is to apply holography to three-dimensional location measurement of particles. We made experiments using the behind scattering beam type ofF-axis holography with an Ar-Ion Laser. We measured three-dimensional coordinates of particles as follows: Centers of gravity for the particles in a 3-D space were measured by the moment method using a stack of x-y cross-section(slice in the depth direction), y-z cross-section, and x-z cross-section images. The present method is verified. Furthermore, a reconstructed image is showed in a 3-D space.
Optical tomography(OT) which consists of interferometry and computer tomography is the important technique that can measure the transient 3D density distribution.But there were difficulties of experimental conplexity when realtime interferometer was used. The photoconductor plastic hologram (PPH) is a new hologram device which can easily make the hologram for the real-time interferometer. Since the image contains 2D information, lots of images taken from different angles should be needed to reconstruct the 3D information. However, the optics configuration will be too complex to obtain the multi-directional image simultaneously. Using the diffusion plate, the laser light could be diffused to multi-direction.Image can be obtained usingonly one hologram plate with multi-directional information. In the computer tomography technique, only the holizontal direction is effective, while the diffused laser contains the whole direction, causing the noise on the hologram. In this study, the lenticular lens is used as the diffusion plate to reflects the laser only in horizontal direction. Therfore the multi-directional fringe images could be clearly obtained. In the experiment the helium jet was measured to demonstrate the effectiveness of the proposed system.
Very large floating structures of several kilometers long and . wide are now considered as possible alternatives to such land-based big facilities as an airport. Since the principal horizontal dimension is so large that the conventional experimental tanks can not comply with the appropriate similarity law, an attempt is made to carry out experiments in a very small water tank. With the use of a very small tank, the entire wave field around a model or the entire response pattern of the model in waves can be visualized by making use of certain optical techniques, which can not be achieved if the conventional water tanks are used.
The wave height distribution around a ship model was measured by means of image measurement system using the difference of illumination scattering between air and water. The authors have developed the image measurement system of wave height distribution, and applied it on the measurement around high-speed craft and displacement type ship model in calm water. Present paper describes the extension of the present technique which enables to obtain the wave height distribution around ship model in regular wave. The measured distribution shows the change of wave pattern as the ship cross over the incident wave.
This study tried to construct the Schlieren observation system to understand the progress process of interesting EHD fluid motion in dielectric liquid. The usual technique applies the visible tracer to the observation of the phenomenon. However, the tracer contaminated in dielectric liquid has the apprehension of electrification. Since, the Schlieren method dose not need a medium such as the tracer, the method gives mechanical aspect of the EHD progress process without the apprehension. As the result, we obtained the worthwhile knowledge about the phenomenon. This paper shows the successful results to understand the progress process.
Illustrating streamlines by computer graphics is a common technique to draw velocity fields in fluid dynamics and electrostatic fields in material science, which both are given as vector data at grid points in the space. However, since too many curvilinear lines usually appear in the images, it is difficult to understand physical meanings of computational results. To overcome this problem, a straightforward but fruitful technique is proposed here. In the present scheme, streamlines are classified according to the minimum value. of magnitude of, for example, the electrostatic field along each streamline. This classification is found useful to obtain intuitive images of stream surfaces by selecting streamlines in order to eliminate redundant information. In this note, the technique is explained along with graphics images to show how helpful to extract important features of the vector data.
Magnetic fluids are suspension of ferromagnetic particles less than 10nm in diameter and it is well-known for the chain(cluster) formation of the magnetic particles under the magnetic field. In the present paper, using the light scattering from the particles, direct visualization on the behavior of cluster formation of the ferromagnetic particle and non-magnetic particles have been made under the magnetic field.
After 1980's numerical simulation approaches have been carried out in order to establish the theory for collecting particle mechanism in Electrostatic Precipitator (hereinafter, ESP). In relation to the Finite Turbulence Diffusion Model in ESP we conducted a numerical calculation to investigate fundamental flow characteristics of Electro-Hydro-Dynamics (EHD) field. In comparison of the results of laminar flow and that of turbulence flow, some significant differences between two flow patterns are there. Especially, the secondary flows by ionic wind in turbulence are smaller than in laminar and also the distribution of effective viscosity in the duct is clarified. The predicted collection efficiency by the Finite Turbulence Diffusion Model is higher than that by the Deutsch Model.
In order to investigate large-scale separated flow in the wind tunnel, surface tuft method was applied to wind tunnel flow which was sucked from side wall. In the region of flow separation, many vortices were observed, which center lines were normal to either side wall or bottom wall.
Video camera calibrations and field experiments have been conducted to measure air change rates using imaging technique. The calibrations for the 8 mm video camera showed that the dark current caused non-linearity at low reflectance. In the field tests, air change rates in the test house were measured by the video camera and the aerosol monitor using smoke candles as tracers. The regression formula as a function of illuminance and camera f-stops was obtained from a total of forty-seven test runs. It was verified that, if the camera could be well adjusted for the experimental conditions using the formura, the video method could measure air change rates with almost the same precision as derived from the decay curves of smoke particle concentrations using the aerosol monitor.
Rcently with improving high-speed performance of vehicle, the wiper characteristics can not be performed enough because the wiper lift acting on the wiper blade decrease of power which press the wiper blade on the windshield. It has been believed that the lift acting on the wiper blade become the maximum at 90° incidense of high speed air. Thus we have been always using 90° incidense when the flow analysis and the lift analysis acting on the wiper blade. However it is not yet cleared that the effect of incidence of high speed air on the lift characteristics acting on the wiper blade. So we measured the incidense of high speed air and the wiper lift characteristics at every wiping angle by using passenger-car, mini-ban and RV vehicles. As the result, the wiper lift becomes the maximum near 50° incidence of high speed in spite of difference of vehicles.
The morphological structure of vascular smooth muscle cells was analyzed in rabbit mesentery, using fluorescent images obtained by confocal laser scanning microscopy. The mesentery sections were stained with specific antibodies against myosin. The 3D image of terminal arterioles was reconstructed based on the sliced images. The resultant image shows, the arterioles were ovally collapsed in the transverse section. The arteriolar wall was consisted of spindle shaped endothelial cells aligned along the flow direction; surrounded by a mono-layer of spirally arranged smooth muscle cells. Individual smooth muscle cell surrounded the vessel to the extent of one to one and half loops. In between the smooth muscle spirals, several gaps were observed; while the endothelial cell arranged like a cobblestone. The dimension of the gap was equivalent to one or two smooth muscle cell width.
We have developed the ultrasonic (US) strain measurement-based elasticity computed tomography for diagnosis of soft tissues. Specifically, we developed the iterative rf-echo phase matching method that provides us considerably accurate estimates of strains generated in vivo in soft tissues due to spontaneous heart motion/extracorporeally applied pressures. Moreover, we have developed a numerical method for stably reconstructing the relative shear modulus distribution with respect to reference shear moduli only from the measured strain data. We also developed the proper configuration method of mechanical sources/reference regions for stably reconstructing it. Since we could verify the feasibility of each method through simulations, and phantom experiments etc, we here focused our attention on application to breast tissues, and unified the methods into a technique by conducting experiments using in vitro pork rib. Finally, we showed a sample shear modulus image obtained on the breast tissue of a healthy volunteer.
The study of the detailed information of precapillary circulation is very important to examine the control method for a total artificial heart or lung. We developed a new system to analyze visualized capillary image on real-time operation with a microscopic CCD and machine vision system. On the present system, in the case of narrow capillary, discrete images are extracted by using partial derivatives of a Gaussian smoothing kernel, and line structures are detected according to parameters of the polynominal. The diameter of the capillary was defined from the parameter of them. In the case of relatively bold capillary or arteriola, ROI was defined by using threshold process. The diameter was detected from the smallest surrounding rectangle of the thresholded region. Template matching technique with sub-pixel accuracy was used to determine the velocity profile. Parameters for template matching were defined from the detected diameter and center of line contour profile. The present method was applied to the measurement of mesentery of a bull frog, and the validity of this system was discussed.
The advance of computerized image processing techniques has opened a new area in flow visualization and quantitative analysis of fluid dynamics. In this study, image analysis methods to measure blood velocity and flow profile in the microcirculation using a high speed video camera and image processing system are proposed. The image gradient method and image correlation method enable us to describe optical flow of blood flow dynamics; two dimensional velocity distribution and radial velocity profiles in the microscopic blood vessels. The results of image analysis indicate that the proposed system is very useful to measure the blood flow velocity with high temporal and spatial resolution.
As an example of image analysis and diagnosis which are done in use of personal compute in the hospital, we indtroduce a quantitative analysis of pulmonary emphysema. The cause of pulmonary emphysema is smoking and this disease expands bronchiolar and alveolar besides destroying them. The criteria (standardization) of qualitative evaluation and diagnosis in use of computed tomography with few stimulation are expected on this account. We use the NIH Image, an image soft of personal computer, and carried out quanlitatve grasp of picture of inspiratory and expiratory of lungs both healthy and emphysema The evaluation index of emphysema was shown at the meeting for the study of pulmonary emphysema in 1999, and with this index, we tried a comparison and reevaluation of our analysis result of NIH Image.
The recruitment of new blood vessels in living tissues is essential for the pathogenesis and prognosis of organ disorders.The present study is concerned with intravital observations of newly formed vascular network in mouse brain, using fluo-rescence video-imaging. This visualization technique is a useful tool to study morphology and physiology of the newly developed vessels. The information obtained from the video-image includes the morphology of vascular network, the time required to develop blood vessels, and the velocity of red blood cells flowing in blood vessels.
A PC level 3D animation tool with easy operation and high cost performance is newly constructed here from numerically analyzed data, especially non visual molecular flows. The software is realized by commanding OpenGL library and using the input data automatically ordering scheme built up here. This 3D-CG computer graphics tool is verified by several examples such as (1) chemical reaction of CH4→CH3OH analyzed by the molecular orbital method, (2) plasma process of Ar→ Ar++eanalyzed by the particle monte-carlo method, and(3) plasma CVD process of SiH2+Ar*→ Si+2H+Ar* analyzed by the molecular dynamics method. As a result, these examples can show very well their essential phenomena which are not known yet and this PC level 3D animation tool is found to be significantly useful and widely applicable .
In this study, the sonoluminescence emitted from the bubbles in a cylindrical flask full of sodium chloride solution, which is oscillated by an ultrasonic wave with a frequency of 36.5 kHz, is captured by a still camera. The spectrum of the sonoluminescence is measured with a monochrometer and a PMT to confirm their spectral properties, especially the sodium D emission line near 589 nm. Also a new computational method for an analysis of a single spherical sonoluminescing bubble in water is proposed, in which the bubble inside is simulated using the Direct Simulation Monte Carlo method, while the motion of the bubble wall follows from the well-known Keller equation. The histories of the bubble radius, pressure and temperature inside the bubble are calculated, revealing a propagation of a shock wave in the bubble.
Vapor-liquid equilibrium of argon is numerically simulated by Monte Carlo method. By NVT ensemble of the MC method, the pressure, volume and temperature for argon are reasonably evaluated at the outside of a vapor-liquid saturated line. Moreover, at the inside of the vapor-liquid saturated line the pressure, volume and temperature are estimated by Gibbs ensemble. However, numerical errors are seemed to be greater at a critical point and liquid phase.