Optimal X(2) filtering method and application to targets and backgrounds with random correlated gray levels

We describe a pattern recognition processor based on a new optimal x(2) filtering method that is designed to localize a target with unknown gray levels appearing on a random background. This processor consists of preprocessing of the analyzed image followed by correlations with binary masks.     

Complex probabilities on R(N) as real probabilities on C(N) and an application to path integrals

We establish a necessary and sufficient condition for averages over complex-valued weight functions on R(N) to be represented as statistical averages over real, non-negative probability weights on C(N). Using this result, we show that many path integrals for time-ordered expectation values of bosonic degrees of freedom in real-valued time can be expressed as statistical averages over ensembles of paths with complex-valued coordinates, and then speculate on possible consequences of this result for the relation between quantum and classical mechanics.     

Fast and low error color encrypted computer-generated hologram based on amplitude-phase modulation with a random mask for an identification tag application

A new APM computer-generated hologram algorithm for minimizing DC components and more effective data recovery is presented for the purpose of an ID tag application. In this method, a technique of randomization of the input data is introduced prior to the Fourier transform. As a result, DC components are localized at the center region, which is only 1 data cell, regardless of input data. The size of the tag pattern is reduced 2.25 times using a color encryption technique. Our experimental result through the image captured by a camera also shows that approximately 50% damaged APM-CGH tags can be reconstructed at a low error rate of about 1.8%.     

Continuous-wave optical parametric oscillator based on periodically poled KTiOPO(4) and its application to spectroscopy

We report a continuous-wave, doubly resonant optical parametric oscillator (OPO) based on the nonlinear material periodically poled KTiOPO(4) and its application to spectroscopy. The OPO, which is pumped by a diode-pumped frequency-doubled Nd:YLF laser at 523 nm, has a low pump-power threshold of 25 mW and can deliver 10 mW of single-frequency output at 1.65 mum for a pump power of 200 mW. The idler wavelength can be temperature tuned at a rate of 0.73 nm/( degrees )C , and smooth tuning of the output frequency over ~3 GHz is achieved by smooth tuning of the pump laser. We demonstrate the practicality of the OPO by recording the absorption spectrum of methane near 1649 nm.     

A study on spatial coherence using quadratic radially distributed apertures (application to confocal imaging)

We study the spatial coherence problem using an amplitude modulation applied to confocal imaging systems. This type of modulation assumes a quadratic radial distribution. The mutual coherence intensity or the coherence factor is calculated and compared with the results obtained for clear circular apertures.     

Comparative study of theSp (2,R) and theSp(6,R) models and an application to theBa chain of isotopes

We investigate the Sp(2, R) model for light and heavy nuclei and compare it to recent applications of the Sp(6, R) model. The same Hamiltonian is used and the basis states will have good angular momentum. We not only confirm that the restricted space of the Sp(6, R) model gives the dominant contribution but also that there is no practical difference from the Sp(6, R) model calculations. The Sp(2, R) model is then applied to the chain of Ba-isotopes which show, according to a recent application of the geometrical model, a dominant prolate behavior with an important γ-unstable component. They represent limiting cases where the Sp(2, R) model can be put to an extreme test. Work supported by CONACyt (No. E120-550/95).     

基于小尺度参考辐射的便携式伽玛射线剂量(率)仪校准方法及应用

针对现有伽玛射线剂量(率)测量仪器检定方法送检距离远、周期长、效率低的不足,中国工程物理研究院核物理与化学研究所采用基于样本仪表的机器预测方法,开展了基于小尺度参考辐射的便携式伽玛剂量(率)仪遂行校准技术研究工作。最终成功地研制了一套辐射防护用伽玛射线剂量(率)仪遂行校准装置,实现了测量标准不确定度不大于5%的良好结果。为伽玛空气比释动能量值的遂行定度提出了一条全新的技术思路,为便携式伽玛剂量(率)仪的现场和野外校准提供了一种全新的示范装备。     

Domain-based local pair natural orbital CCSD(T) calculations of strongly correlated electron systems: Examination of dynamic equilibrium models based on multiple intermediates in S1 state of photosystem II

ABSTRACT

Domain-based local pair natural orbital (DLPNO) coupled cluster single and double (CCSD) methods with perturbative triples (T) correction with NormalPNO were used to compute energies for twelve different S₁ structures of the CaMn₄O₅ cluster in the oxygen evolving complex (OEC) of photosystem II (PSII). The DLPNO-CCSD(T₀) calculations with TightPNO for the important six structures among them revealed that the right (R)-opened S_1XYZW structures were more stable than the corresponding left (L)-opened structures (X?=?O₍₅₎, Y?=?W2, Z?=?W1, and W?=?O₍₄₎) of CaMn₄O₅. The three different S₁ structures belonging to the R-opened type (S_1acca, S_1bbca, and S_1abcb, where O^2-?=?a, OH^-?=?b and H₂O?=?c) were found nearly degenerated in energy, indicating the possibility of the coexistence of different structures in the S₁ state. The DLPNO-CCSD(T₀) calculations with TightPNO supported the proposal of a dynamic equilibrium model based on the multi-intermediate structures for the S₁ state, which is also in agreement with EPR and other experimental and hybrid DFT computational results. Implications of the computational results are discussed in relation to scope and applicability of NormalPNO and TightPNO for the CCSD(T₀) calculations of strongly correlated electron systems such as 3d transition-metal complexes.     

Combined application of AES and XPS to study carbon diffusion through the selvedge of an Fe(100) surface

Diffusion of carbon from an Fe(100) surface into the bulk, following halocarbon adsorption, is modelled using experimental data from AES and XPS experi electrons (272 eV) in a dense monolayer of halogen atoms (Cl, Br) is found by a variety of experimental methods to be ～3Å, a value substantially sm inferred from the combined information provided by the AES and XPS experiments, the concentration profile of carbon perpendicular to the surface follow function. The importance of accurate data for electron escape depths and of experimental detection limits for quantitative electron spectroscopy of a s     

Modelling and simulation of high-frequency (100 MHz) ultrasonic linear arrays based on single crystal LiNbO3

Background

High-frequency ultrasonic transducer arrays are essential for high resolution imaging in clinical analysis and Non-Destructive Evaluation (NDE). However, the fabrication of conventional backing-layer structure, which requires a pitch (distance between the centers of two adjacent elements) of half wavelength in medium, is really a great challenge.

Objective and method

Here we present an alternative buffer-layer structure with a silicon lens for volumetric imaging. The requirement for the size of the pitch is less critical for this structure, making it possible to fabricate high-frequency (100 MHz) ultrasonic linear array transducers. Using silicon substrate also makes it possible to integrate the arrays with IC (Integrated Circuit). To compare with the conventional backing-layer structure, a finite element tool, COMSOL, is employed to investigate the performances of acoustic beam focusing, the influence of pitch size for the buffer-layer configuration, and to calculate the electrical properties of the arrays, including crosstalk effect and electrical impedance.

Results

For a 100 MHz 10-element array of buffer-layer structure, the ultrasound beam in azimuth plane in water could be electronically focused to obtain a spatial resolution (a half-amplitude width) of 86 μm at the focal depth. When decreasing from half wavelength in silicon (42 μm) to half wavelength in water (7.5 μm), the pitch sizes weakly affect the focal resolution. The lateral spatial resolution is increased by 4.65% when the pitch size decreases from 42 μm to 7.5 μm. The crosstalk between adjacent elements at the central frequency is, respectively, −95 dB, −39.4 dB, and −60.5 dB for the 10-element buffer, 49-element buffer and 49-element backing arrays. Additionally, the electrical impedance magnitudes for each structure are, respectively, 4 kΩ, 26.4 kΩ, and 24.2 kΩ, which is consistent with calculation results using Krimholtz, Leedom, and Matthaei (KLM) model.

Conclusion

These results show that the buffer-layer configuration is a promising alternative for the fabrication of high-frequency ultrasonic linear arrays dedicated to volumetric imaging.     

Removal of nickel(II) ions from aqueous solutions using the natural clinoptilolite and preparation of nano-NiO on the exhausted clinoptilolite

The natural zeolite tuff (clinoptilolite) from a Serbian deposit has been studied as adsorbent for Ni(II) ions from aqueous solutions. Its sorption capacity at 298 K varies from 1.9 mg Ni g⁻¹ (for the initial solution concentration of 100 mg Ni dm⁻³) to 3.8 mg Ni g⁻¹ (for C₀ = 600 mg Ni dm⁻³) and it increases 3 times at 338 K. The sorption is best described by the Sips isotherm model. The sorption kinetics follows the pseudo-second-order model, the activation energies being 7.44, 5.86, 6.62 and 6.63 kJ mol⁻¹ for C₀ = 100, 200, 300 and 400 mg Ni dm⁻³, respectively. The sorption involves a film diffusion, an intra-particle diffusion, and a chemical cation-exchange between the Na⁺ ions of clinoptilolite and the Ni²⁺ ions. The sorption is endothermic (ΔH° being 37.9, 33.4, 30.0, 27.7 and 24.3 kJ mol⁻¹ for C₀ = 100, 200, 300, 400 and 600 mg Ni dm⁻³, respectively) and spontaneous in the 298-338 K temperature range. Thermal treatment of the Ni(II)-loaded clinoptilolite results in the formation of spherical nano-NiO particles of approx. 5 nm in diameter which are randomly dispersed in the clinoptilolite lattice.     

A prediction theory of random level distribution based on a generalized difference type of Fokker-Planck equation and its application to environmental noise and vibration,I: Theoretical study

For generalized discrete random signals, of arbitrary correlations among arbitrarily chosen samples, and also arbitrary distribution form, the short time prediction problem, in terms of the transition probability distribution, is theoretically considered, first for discrete time interval sampling. A general expression is derived from which any signal statistics, e.g., the average, the variance, the 90% range value, and so on, can be predicted. This general expression is equivalent to the well-known Fokker-Planck equation, with continuous time sampling, in the special case of a Markovian process. Explicit algorithms for estimating moment statistics of arbitrary order are derived, by introducing the generalized difference equation of Fokker-Planck type for the probability distribution function.     

A prediction theory of random level distribution based on a generalized difference type of Fokker-Planck equation and its application to environmental noise and vibration,II: Experimental study

In a companion paper [1], a procedure for solving the short time prediction problem in terms of the transition probability distribution has been theoretically derived, for discrete time-sampled data. Explicit algorithms for estimating the non-stationary moment statistics of arbitrary order also have been derived, based on a generalized difference equation of Fokker-Planck type for the conditional probability distributed function, which is central to the theory. In this paper, evidence for the validity and effectiveness of the proposed method is presented, as obtained not only by means of digital simulation but also by using road traffic noise data obtained experimentally in Hiroshima. For several non-stationary random processes simulated by means of random numbers, the theoretical and experimental conditional probability functions are compared. For non-stationary road traffic noise data the theoretically predicted and experimentally determined confidence intervals are compared; in these comparisons several types of conditional probability function and various values of weighting parameter are used in the algorithm. All of the theoretical results show good agreement with the experimental results.     

High-frequency hearing in phocid and otariid pinnipeds: an interpretation based on inertial and cochlear constraints (L)

Audiograms in air and underwater, determined by previous workers for four pinniped species, two eared seals (Otariidae) and two phocids (Phocidae), are supplemented here by measurements on their middle ear ossicular mass, enabling mechanistic interpretations of high-frequency hearing and audiogram differences. Otariid hearing is not largely affected by the medium (air/water). This indicates that cochlear constraints limit high-frequency hearing in otariids. Phocids, however, have massive middle ear ossicles, and underwater hearing has radically shifted towards higher frequencies. This suggests that the high-frequency hearing of phocids in air is constrained by ossicle inertia.     

State-of-the-art advantages and drawbacks on the application of vibrational spectroscopy to monitor alcoholic fermentation (beer and wine)

Wine production is directly linked with the monitoring of the fermentation and critical fermentation parameters such as total sugars and ethanol concentration, and the production of CO₂. Commonly used sensors applied in the wine industry to monitor wine fermentation are those based in single sensors such as temperature probes and manual density measurements (e.g., specific gravity). These sensors are used several times per day and have been the only source of data available from which the stage of the fermentation and the evolution rate could be monitored. Therefore, an ideal method for fermentation process control and monitoring should enable a direct rapid, precise, and accurate determination of several target compounds, with minimal or no sample preparation and reagent consumption. This article reviews the state of the art in the applications of both near and mid infrared spectroscopy to monitor beer and wine fermentation.     

Static and dynamic analysis of an all-optical inverter based on a Vertical Cavity Semiconductor Optical Amplifier (VCSOA)

We report the static and dynamic properties of an all-optical inverter based on an 850 nm Vertical Cavity Semiconductor Optical Amplifier (VCSOA). The inverter exhibits low switching power requirements (~ 15 μW), large on/off contrast ratio (> 11 dB), and high speed operation (~ 1.4 GHz). Large and small signal measurements show that the speed of operation and the on/off contrast ratio improve with increased bias current. This holds important prospects for the development of VCSOA-inverters for high-speed, low-power optical logic applications. Finally, a theoretical model of the VCSOA-inverter has been employed giving good agreement with experiments.     

Magnetic contribution to the Debye temperature and the lattice heat capacity of ferromagnetic rare-earth metals (using gadolinium as an example)

A thermodynamic approach that describes the spontaneous magnetic contribution to the Debye temperature of a ferromagnetic metal has been developed using the theory of second-order Landau phase transitions. It is shown that the essential cause of the formation of the spontaneous magnetic contribution to the Debye temperature is the magnetostrictive variation of the volume. By using an expression for the spontaneous magnetic contribution to the Debye temperature, the magneto-phonon contribution to the lattice specific heat is found. The resulting generalized expression for the Debye temperature is found to be in good agreement with experimental data concerning the elastic constants of the ferromagnetic phase of gadolinium. The magneto-phonon heat capacity makes an appreciable contribution to the heat-capacity anomaly of gadolinium close to the Curie point. Fiz. Tverd. Tela (St. Petersburg) 41, 1248–1253 (July 1999)