Showing papers by "University of Electro-Communications published in 2004"
TL;DR: In this article, the authors suggest using a two-color evanescent light field around a subwavelength-diameter fiber to trap and guide atoms, which allows confinement of atoms to two straight lines parallel to the fiber axis.
Abstract: We suggest using a two-color evanescent light field around a subwavelength-diameter fiber to trap and guide atoms. The optical fiber carries a red-detuned light and a blue-detuned light, with both modes far from resonance. When both input light fields are circularly polarized, a set of trapping minima of the total potential in the transverse plane is formed as a ring around the fiber. This design allows confinement of atoms to a cylindrical shell around the fiber. When one or both of the input light fields are linearly polarized, the total potential has two local minimum points in the transverse plane. This design allows confinement of atoms to two straight lines parallel to the fiber axis. Due to the small thickness of the fiber, we can use far-off-resonance fields with substantially differing evanescent decay lengths to produce a net potential with a large depth, a large coherence time, and a large trap lifetime. For example, a 0.2-\ensuremath{\mu}m-radius silica fiber carrying 30 mW of 1.06-\ensuremath{\mu}m-wavelength light and 29 mW of 700-nm-wavelength light, both fields circularly polarized at the input, gives for cesium atoms a trap depth of 2.9 mK, a coherence time of 32 ms, and a recoil-heating-limited trap lifetime of 541 s.
251 citations
TL;DR: In this article, the authors show that the gradient force of a red-detuned evanescent wave field in the fundamental mode of a silica fiber can balance the centrifugal force when the fiber diameter is about two times smaller than the wavelength of the light and the component of the angular momentum of the atoms along the fiber axis is in an appropriate range.
Abstract: We suggest using an evanescent wave around a thin fiber to trap atoms. We show that the gradient force of a red-detuned evanescent-wave field in the fundamental mode of a silica fiber can balance the centrifugal force when the fiber diameter is about two times smaller than the wavelength of the light and the component of the angular momentum of the atoms along the fiber axis is in an appropriate range. As an example, the system should be realizable for cesium atoms at a temperature of less than $0.29\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$ using a silica fiber with a radius of $0.2\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ and a $1.3\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$-wavelength light with a power of about $27\phantom{\rule{0.3em}{0ex}}\mathrm{mW}$.
181 citations
TL;DR: In this paper, the authors studied the properties of the field in the fundamental mode HE11 of a vacuum-clad subwavelength-diameter optical fiber using the exact solutions of Maxwells equations.
168 citations
TL;DR: In this paper, volume holographic recording in silica-nanoparticle-dispersed methacrylate photopolymers with reduced scattering loss as low as 2% was demonstrated.
Abstract: We demonstrate volume holographic recording in silica-nanoparticle-dispersed methacrylate photopolymers with reduced scattering loss as low as 2%. This is made possible by use of 13-nm silica nanoparticles. As a result a net diffraction efficiency near 100% is achieved for a transmission volume hologram of 45-μm thickness. Grating buildup dynamics are measured for various nanoparticle concentrations, and the effects of nanoparticle size on refractive-index modulation and polymerization shrinkage are also evaluated.
159 citations
TL;DR: A new multi-class SVM method that can reduce the number of hyperplanes of the one-against-one method and thus it returns fewer support vectors and a direct acyclic graph SVM based testing methodology that improves the testing time of the DAGSVM method.
Abstract: The support vector machine (SVM) has a high generalisation ability to solve binary classification problems, but its extension to multi-class problems is still an ongoing research issue. Among the existing multi-class SVM methods, the one-against-one method is one of the most suitable methods for practical use. This paper presents a new multi-class SVM method that can reduce the number of hyperplanes of the one-against-one method and thus it returns fewer support vectors. The proposed algorithm works as follows. While producing the boundary of a class, no more hyperplanes are constructed if the discriminating hyperplanes of neighbouring classes happen to separate the rest of the classes. We present a large number of experiments that show that the training time of the proposed method is the least among the existing multi-class SVM methods. The experimental results also show that the testing time of the proposed method is less than that of the one-against-one method because of the reduction of hyperplanes and support vectors. The proposed method can resolve unclassifiable regions and alleviate the over-fitting problem in a much better way than the one-against-one method by reducing the number of hyperplanes. We also present a direct acyclic graph SVM (DAGSVM) based testing methodology that improves the testing time of the DAGSVM method.
155 citations
TL;DR: In this paper, the phase and amplitude anomalies in subionospheric LF signal (40 kHz) along the path Japan-Kamchatka of 2300 km were studied for the data observed by means of a digital OminiPAL receiver for 2 years.
Abstract: The phase (P) and amplitude (A) anomalies in subionospheric LF signal (40 kHz) along the path Japan–Kamchatka of 2300 km have been studied for the data observed by means of a digital OminiPAL receiver for 2 years. The empirical model of background P and A daily variations for quiet and disturbed geomagnetic conditions in the absence of seismic activity is developed. We pay special attention to the P and A features during large magnetic storms. A sensitivity threshold of LF signal to deforming influence of the geomagnetic and seismic factors is defined. Two cases of bay-like behavior of LF phase and amplitude in nighttime are described as a clear earthquake precursor of LF signal. We have found from the statistical study that LF signal effect is observed only for earthquakes with M⩾5.5 and we discuss the possible mechanisms of the effect.
154 citations
TL;DR: SmartTouch uses optical sensors to gather information and electrical stimulation to translate it into tactile display, which makes physical contact with an object and touches the surface information of any modality, even those that are typically untouchable.
Abstract: Augmented haptics lets users touch surface information of any modality. SmartTouch uses optical sensors to gather information and electrical stimulation to translate it into tactile display. Augmented reality is an engineer's approach to this dream. In AR, sensors capture artificial information from the world, and existing sensing channels display it. Hence, we virtually acquire the sensor's physical ability as our own. Augmented haptics, the result of applying AR to haptics, would allow a person to touch the untouchable. Our system, SmartTouch, uses a tactile display and a sensor. When the sensor contacts an object, an electrical stimulation translates the acquired information into a tactile sensation, such as a vibration or pressure, through the tactile display. Thus, an individual not only makes physical contact with an object, but also touches the surface information of any modality, even those that are typically untouchable.
152 citations
TL;DR: In this article, a robust adaptive boundary control scheme for axially moving string under a spatio-temporally varying tension and an unknown boundary disturbance is investigated, where the lower bound of the tension variation is assumed to be sufficiently larger than the derivatives of the higher bound.
150 citations
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TL;DR: In this paper, the authors studied the properties of the electric field in the fundamental mode of a vacuum-clad optical fiber using the exact solutions of Maxwell's equations and obtained simple analytical expressions for the total intensity of the field.
Abstract: We study the properties of the field in the fundamental mode HE$_{11}$ of a vacuum-clad \textit{subwavelength-diameter} optical fiber using the exact solutions of Maxwell's equations. We obtain simple analytical expressions for the total intensity of the electric field. We discuss the origin of the deviations of the exact fundamental mode HE$_{11}$ from the approximate mode LP$_{01}$. We show that the thin thickness of the fiber and the high contrast between the refractive indices of the silica core and the vacuum clad substantially modify the intensity distributions and the polarization properties of the field and its components, especially in the vicinity of the fiber surface. One of the promising applications of the field around the subwavelength-diameter fiber is trapping and guiding of atoms by the optical force of the evanescent field.
135 citations
TL;DR: In this article, four sample types of nanostructured titanium dioxide (TiO 2 ) electrodes were studied, variously prepared with TiO 2 nanocrystalline particles of different sizes (15 and 27nm in diameter) and with the addition of polyethylene glycol (PEG) binders having two different molecular weights (MW) (20,000 and 500,000).
Abstract: Four sample types of nanostructured titanium dioxide (TiO 2 ) electrodes were studied, variously prepared with TiO 2 nanocrystalline particles of different sizes (15 and 27 nm in diameter) and with the addition of polyethylene glycol (PEG) binders having two different molecular weights (MW) (20,000 and 500,000). CdSe nanoparticles (CdSe quantum dots: CdSe QDs) were adsorbed on to each of the four types of TiO 2 electrode using a chemical deposition technique. Photoacoustic (PA) and photoelectrochemical (PEC) current spectra were measured, together with the incident photon to current conversion efficiency (IPCE). The photosensitization by the CdSe QDs was confirmed. It was found that the PEC current and IPCE are strongly dependent on the TiO 2 nanoparticle size and the MW of PEG in the TiO 2 /water paste. The correlation of the PEC and IPCE with the microstructure and the electron diffusion coefficient for each of TiO 2 nanostructured electrode type are discussed, providing information which could lead to the optimization of dye-sensitized solar cells (DSSC).
130 citations
29 Oct 2004
TL;DR: A visualization system of a NIDS log, named SnortView, is proposed, which supports administrators in analyzing NIDS alerts much faster and much more easily and introduces some visualization techniques such as overlayed statistical information, source-destination matrix, and so on.
Abstract: False detection is a major issue in deploying and maintaining Network-based Intrusion Detection Systems (NIDS). Traditionally, it is recommended to customize its signature database (DB) to reduce false detections. However, it requires quite deep knowledge and skills to appropriately customize the signature DB. Inappropriate customization causes the increase of false negatives as well as false positives. In this paper, we propose a visualization system of a NIDS log, named SnortView, which supports administrators in analyzing NIDS alerts much faster and much more easily. Instead of customizing the signature DB, we propose to utilize visualization to recognize not only each alert but also false detections. The system is based on a 2-D time diagram and alerts are shown as icons with different styles and colors. In addition, the system introduces some visualization techniques such as overlayed statistical information, source-destination matrix, and so on. The system was used to detect real attacks while recognizing some false detections.
TL;DR: In this article, a general concept of mechanisms of preseismic phenomena in the atmosphere and ionosphere is presented, and the authors conclude that upward migration of fluid substrate matter (bubble) can lead to ousting of hot water/gas near the ground surface and cause an earthquake (EQ) itself in the strength-weakened area.
Abstract: . We present a general concept of mechanisms of preseismic phenomena in the atmosphere and ionosphere. After short review of observational results we conclude: 1. Upward migration of fluid substrate matter (bubble) can lead to ousting of the hot water/gas near the ground surface and cause an earthquake (EQ) itself in the strength-weakened area; 2. Thus, time and place of the bubble appearance could be random values, but EQ, geochemistry anomaly and foreshocks (seismic, SA and ULF electromagnetic ones) are casually connected; 3. Atmospheric perturbation of temperature and density could follow preseismic hot water/gas release resulting in generation of atmospheric gravity waves (AGW) with periods in a range of 6–60min; 4. Seismo-induced AGW could lead to modification of the ionospheric turbulence and to the change of over-horizon radio-wave propagation in the atmosphere, perturbation of LF waves in the lower ionosphere and ULF emission depression at the ground.
TL;DR: In this paper, high-power laser experiments yield an optical-to-optical conversion efficiency of 30% for Nd (0.6 at%):YAG ceramic as compared to 34% for an Nd single crystal.
Abstract: Nd: YAG ceramic materials have been synthesized using vacuum sintering technique with the raw materials prepared by the nano-crystalline methods. The spectroscopic studies suggest overall improvement in absorption and emission and reduction in scattering loss. Judd-Ofelt analysis has been employed to compute the relevant spectroscopic and radiative parameters of the material. The SEM and TEM measurements reveal the excellent optical quality of the ceramic with low pore volume and narrow grain boundary. Fluorescence and Raman measurements reveal that the Nd/sup 3+/-doped YAG ceramic is almost equivalent to its single-crystal counterpart in its radiative and nonradiative properties. Individual Stark levels for /sup 2s+1/L/sub J/ manifolds are obtained from the absorption and fluorescence spectra and are analyzed to identify the stimulated emission channels possible in the Nd: YAG ceramic. Laser performance studies favor the use of high-concentration Nd: YAG ceramics in the design of an efficient microchip laser. With 4 at% Nd: YAG ceramic acting as a microchip laser, we obtained a slope efficiency of 40%. High-power laser experiments yield an optical-to-optical conversion efficiency of 30% for Nd (0.6 at%):YAG ceramic as compared to 34% for an Nd (0.6 at%):YAG single crystal. The oscillation experiments at 1.3 mm gives a slope efficiency of 35%. Optical gain measurements conducted in these materials also show values comparable to single crystal, supporting that these materials could be suitable substitutes to single crystals in solid-state laser applications.
TL;DR: In this paper, a new strategy for fault-tolerant control system design has been proposed using multiple controllers, which is shown to be unique in the sense that the resulting control system neither suffers from the problem of conservativeness of conventional passive fault tolerant control nor from the risk of instability associated with active fault tolerance.
Abstract: In this paper, a new strategy for fault-tolerant control system design has been proposed using multiple controllers. The design of such controllers is shown to be unique in the sense that the resulting control system neither suffers from the problem of conservativeness of conventional passive fault-tolerant control nor from the risk of instability associated with active fault-tolerant control in case that an incorrect fault detection and isolation decision is made. In other words, the stability of the closed-loop system is always ensured regardless of the decision made by the fault detection and isolation scheme. A correct decision will further lead to optimal performance of the closed-loop system. This paper deals with the conflicting requirements among stability, redundancy, and graceful degradation in performance for fault-tolerant control systems by using robust control techniques. A detailed design procedure has been presented with consideration of parameter uncertainties. Both total and partial actuator failures have been considered. This new control strategy has been demonstrated by controlling a McDonnell F-4C airplane in the lateral-direction through simulation. Copyright © 2004 John Wiley & Sons, Ltd.
28 Sep 2004
TL;DR: In this paper, a virtual pheromone system was proposed for cooperative multi-robot foraging tasks in which chemical signals were simulated with the graphics projected on the floor, and the robots decide their action depending on the color information of the graphics.
Abstract: In multi-robot system, communication is indispensable for effective cooperative working. In this system, direct communication by physical methods such as light, sound, radio wave is quite general. But in biological system, especially in the insect world, not only the physical but also the chemical communication methods can be observed. As the chemical methods have some unique properties, it is challenging to apply such a method to the cooperative multi-robot system. Unfortunately, to treat real chemical materials for the robots is not easy for now because of some technical difficulties. In this paper, we propose virtual pheromone system in which chemical signals are simulated with the graphics projected on the floor, and in which the robots decide their action depending on the color information of the graphics. We examined the performance of this system through the foraging task, which is one of the most popular tasks for multi-robot system and is generally observed in ant societies.
TL;DR: In this article, a high-power, continuous-wave 0.6% Nd3+-doped ceramic Y3Al5O12 (Nd:YAG) laser has been developed.
Abstract: A high-power, continuous-wave 0.6% Nd3+-doped ceramic Y3Al5O12 (Nd:YAG) laser has been developed. 110 W laser output at 1064 nm was obtained, with a slope efficiency of about 41%. The M2 factor was found to be around 6. The laser performance of the ceramic laser material was found to compare favorably with that obtained with single crystal Nd:YAG.
TL;DR: In this paper, a single-crystalline erbium compound is formed by coating a Si(100) substrate with an ErCl3∕ethanol solution, followed by rapid thermal oxidation and annealing.
Abstract: Optically active and electrically excitable erbium complexes on silicon are made by wet-chemical synthesis. The single-crystalline Er–Si–O compound is formed by coating a Si(100) substrate with an ErCl3∕ethanol solution, followed by rapid thermal oxidation and annealing. Room-temperature Er-related 1.53μm photoluminescence is observed with a peak linewidth as small as 4meV. The complexes can be excited directly into the Er intra-4f states, or indirectly, through photocarriers. Er concentrations as high as 14at.% are achieved, incorporated in a crystalline lattice with a 0.9nm periodicity. Thermal quenching at room temperature is only a factor 5, and the lifetime at 1.535μm is 200μs.
TL;DR: There was the highest correlation between parameter of theta and subjective evaluation, and thus theta was considered an effective physiological parameter for numerically evaluating simulator sickness.
TL;DR: In this article, a receding horizon predictive control (RBF-ARX-MPC) strategy based on the Gaussian radial basis function model is proposed to describe the system behavior.
TL;DR: In this article, the spectral density ratio between the horizontal and vertical components (polarization) exhibits an anomalous behavior two weeks before the earthquake, which suggests that this anomalous change might be a possible signal associated with the earthquake preparation phase.
Abstract: Previous studies on Spitak, Loma Prieta, and Guam earthquakes indicate that large earthquakes were accompanied by preceding magnetic anomalies. In order to confirm these facts and to investigate ULF phenomena in details, a network of ULF magnetometers has been installed in Japan. Network observations including small arrays have been carried out. Also, the geomagnetic data observed at Matsukawa station associated with Iwateken Nairiku Hokubu earthquake (M6.1, September 3, 1998, depth 10 km) are presented. 4.5 years data have been analyzed and the obtained result is discussed. The variation of spectral density ratio between the horizontal and vertical components (polarization) exhibits an anomalous behavior two weeks before the earthquake. This is a unique change discovered from the rather long-term analysis, which suggests that this anomalous change might be a possible signal associated with the earthquake preparation phase.
TL;DR: In this paper, the pulsed laser ablation (PLA) experiments of rutile single crystal surfaces were carried out in water solution to prepare nanosized titania particles, and the solvated PLA species were transparent as produced and changed to a lighter blue solution with some precursors for filamentous species.
Abstract: The pulsed laser ablation (PLA) experiments of rutile single crystal surfaces were carried out in water solution to prepare nanosized titania particles. The solvated PLA species were transparent as produced and changed to a lighter blue solution with some precursors for filamentous species (in several days), then finally changed to white enlarged filamentous species (in 2−4 weeks). The solvated PLA species were measured as uniform nanoparticles with a size below 10 nm by TEM measurements and showed the absorption−photon energy relation for the direct transition with a band gap of 5.3−5.5 eV. The band-gap values were elucidated with quantum confinement size effects. It was assumed that the primary solvated species should have a size of about 1 nm and they were agglomerated to be the secondary species. The Mie scattering is responsible for the “blue” color, which proves that the size enlargement process exists on the PLA species in water. The filamentous species are composed of mainly the anatase form, whic...
TL;DR: In this article, the authors have succeeded in observing sprites for winter lightning in the Hokuriku area (Japan Sea side) of Japan in the winter of 2001/2002, and the optical results on 3 days are compared with the corresponding characteristics of parent (causative) lightning with particular attention to the significant differences between Hokurike winter lightning and the more widely studied continental lightning.
Abstract: [1] We have succeeded in observing sprites for winter lightning in the Hokuriku area (Japan Sea side) of Japan in the winter of 2001/2002. The optical results on 3 days are compared with the corresponding characteristics of parent (causative) lightning with particular attention to the significant differences between Hokuriku winter lightning and the more widely studied continental lightning. Despite significant differences with Hokuriku winter lightning, we have found nearly the same sprite properties as already observed in the U.S. continent with a significant difference (simpler shape for Hokuriku winter sprite). Then, we have also discussed the criteria for sprite occurrence. Specifically, two similar criteria are found: (1) cloud-to-ground discharges of positive polarity and (2) the presence of a certain threshold in vertical charge moment (200–300 C km) (roughly consistent with that for the U.S. continent). Mesoscale convective systems are not necessary to store the charge necessary for sprites, but the parent Hokuriku winter clouds are substantially smaller than the minimum scale for sprite occurrence in the continental lightning; however, it is larger in area than ordinary summer thunderclouds. However, there may exit another condition such as clustering or self-organizing effect of thunderclouds for sprite production.
TL;DR: A robust fuzzy controller is designed that achieves good speed of response without actuator saturations in the control design of a three degrees of freedom (3-DOF) RC helicopter.
Abstract: This paper presents a practical design approach to the stabilization of a three degrees of freedom (3-DOF) RC helicopter. First, the nonlinear model of the RC helicopter is constructed. To facilitate control design, a simplified version of the nonlinear model is derived. A Takagi-Sugeno fuzzy model is then constructed to represent the simplified nonlinear model. The control purpose is to stabilize the RC helicopter while taking into account practical performance considerations in terms of good speed of response and small control effort. To achieve the control objective, we impose a decay rate condition to ensure a good speed of response and an input constraint condition to avoid actuator saturations in the control design. Both conditions are represented in terms of linear matrix inequalities (LMIs). By simultaneously solving them, we render a stabilizing fuzzy controller that achieves good speed of response with small control effort. However, the controller designed for the simplified model can not always stabilize the original nonlinear model due to discrepancies introduced via the simplification process. To overcome this limitation, we design a robust fuzzy controller to compensate for the modeling discrepancies. The resulting robust stability condition with good speed of response is represented in terms of LMIs. By simultaneously solving this condition together with an input constraint condition, we arrive at a robust stabilizing fuzzy controller that achieves good speed of response without actuator saturations. Both simulation and experimental results are included to demonstrate the viability and applicability of the approach.
TL;DR: In this article, a feasibility study of the use of electromagnetic phenomena in short-term earthquake prediction was carried out by two institutions (RIKEN and NASDA) under the Integrated Earthquake Frontier Project.
Abstract: After the disastrous Kobe earthquake, the former Science and Technology Agency (STA) of Japanese Government proposed the Integrated Earthquake Frontier Project. Within the framework of this project, two institutions (RIKEN and NASDA (National Space Development Agency of Japan)) were asked to carry out over five years a feasibility study of the use of electromagnetic phenomena in short-term earthquake prediction. Since 1996 the RIKEN group has been engaged in the study of earth current and related phenomena. Meanwhile, under the NASDA project named “Earthquake Remote Sensing Frontier Project”, we performed an overall study of seismo-electromagnetic phenomena occurring not only in the lithosphere, but also in the atmosphere and ionosphere. Our five-year study has yielded that the seismic effect expresses itself not only in the lithosphere (such as by ULF electromagnetic emissions, acoustic emissions etc.), but also in the atmosphere and ionosphere (by means of pre-existing transmitter signals). Most importantly, we find convincing evidence for seismo-ionospheric perturbations on the basis of subionospheric VLF/LF signals. We have established a new challenging science field, “Lithosphere–atmosphere–ionosphere coupling” or “Electromagnetics in the coupled lithosphere–atmosphere–ionosphere system”. The study of this coupling would contribute to the scientific short-term earthquake prediction.
15 Sep 2004-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effect of pressing temperature on microstructural development under ECAP conditions was studied in an as-cast 7475 aluminum alloy at temperatures from 523 to 673 K.
Abstract: The effect of pressing temperature on microstructural development under ECAP conditions was studied in an as-cast 7475 aluminum alloy at temperatures from 523 to 673 K. The samples were pressed by using route A up to strains of 12. New equiaxial grains with high angle boundaries (HABS) start to be formed after three passes and then gradually developed with repeated ECAP, finally, followed by fully development of a new fine-grained structure. The average (sub)grain size tends to increase and the aspect ratio decreases with increasing pressing temperature. The misorientation distribution of strain-induced dislocation boundaries shows a single peak type at low angle misorientations until second pass and then gradually shifts to higher angles with increasing of strain. Increase in pressing temperature retards the transformation kinetics from low angle boundaries to high angle ones, while the fraction of the latter as well as the average misorientation approach a same saturation value irrespective temperature in high strain. The mechanism of ultra-fine grain formation during ECAP is discussed.
TL;DR: In this paper, a phase diagram against the off-site repulsion $V$ and band filling $n$ for the extended, repulsive Hubbard model on the square lattice with the fluctuation exchange approximation was obtained.
Abstract: In order to explore how superconductivity arises when charge fluctuations and spin fluctuations coexist, we have obtained a phase diagram against the off-site repulsion $V$ and band filling $n$ for the extended, repulsive Hubbard model on the square lattice with the fluctuation exchange approximation. We have found the existence of (i) a transition between ${d}_{xy}$ and ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ pairing symmetries, (ii) $f$-pairing in between the ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ and CDW phases for intermediate $0.5lnl1.0$ and large $V$, and (iii) for anisotropic cases the pairing symmetry changing, in agreement with a previously proposed ``generic phase diagram,'' as $d\ensuremath{\rightarrow}f\ensuremath{\rightarrow}s$ when $V$ (hence the charge fluctuations) are increased. All these are consequences of the structure in the charge and spin susceptibilities, which have peaks habitating at common or segregated positions in $k$ space.
TL;DR: In this article, the preferential nucleation of dynamic recrystallization (DRX) was investigated in copper polycrystals deformed in compression at 873K and a true strain rate of 2.9 · 10 · 4 s � 1.
TL;DR: An integrated product and process modeling (IPPM) framework for collaborative product design through the Internet is described and an agent-based approach is proposed for the computer support of hierarchical and heterarchical design topologies.
Abstract: Concurrent engineering (CE) has been widely accepted as an effective engineering practice for decreasing product development time, improving quality, decreasing manufacturing costs, and improving c...
TL;DR: In this paper, the cage symmetry was determined by measuring the 13C NMR spectra of the anion of the Ce atom using high-performance liquid chromatography (HPLC).
Abstract: Ce@C82 is isolated by high-performance liquid chromatography (HPLC) and the cage symmetry is determined as C2v by measuring the 13C NMR spectra of its anion. The 13C NMR peaks of [Ce@C82]- show temperature-dependent shifts ascribed to the f electron remaining on the Ce atom. Both Ce@C82 and [Ce@C82]- are silent in electron spin resonance spectroscopy (ESR) because of the highly anisotropic g matrix as well as of the fast relaxation process originating from the orbital angular momentum of the f electron. This is the complementary relationship to the observation of the paramagnetic shift in 13C NMR. [Ce@C82]- has lower stability in air than [La@C82]-.
TL;DR: In this paper, the nucleation mechanisms of dynamic recrystallization (DRX) were investigated in copper bicrystals deformed in tension at 923 K at a strain rate of 4.2 × 10 −4 s −1.