Development of a dual-isotope procedure for the tagging and identification of manufactured products: application to explosives

A novel chemical tagging approach, based on a dual-isotope procedure, is presented. The method has been applied to explosives tagging. The method is based on the addition to the explosive of two enriched isotopes of the same element, which may be already present within it, at a given molar ratio. This dual-isotope approach will give a unique fingerprint to the tagged explosive. Further, the authentication of the tagged explosive or its residues will be obtained by comparison of the ratio of molar fractions experimentally measured by inductively coupled plasma mass spectrometry (ICP-MS) with the molar fraction ratio of the tagging mixture. The novelty of this tagging method relies on working with isotope abundances and molar fraction ratios instead of the classical isotope ratios, and this fact constitutes the strong point of the described approach since the molar ratio is not affected by physical, chemical, or biochemical processes, and it is also not disturbed by environmental contamination with the natural abundance element. Furthermore, the use of molar fraction ratios overcomes the nonhomogeneous distribution of the tagging element within the explosive. As the tagging element can be present at trace or ultratrace levels, a very small amount of enriched isotopes needs to be added, denoting a low cost solution. Also, the use of enriched stable isotopes of nontoxic elements will have negligible health effects or affect the environment.     

A metal marking method based on laser shock processing

The stress effect generated by a high-energy short-pulse laser is utilized to achieve performance enhancement or precise shaping of metal material components in laser shock technology. A method of marking metal materials using laser shock technology is introduced in this paper. The physical principle is the effect of thickness of absorbing layers on the intensity of a laser-induced shockwave, which results in forming the mark with a certain shape using local surface plastic deformation. The marking method based on the principle of laser shock overcomes the deficiency of traditional marking methods that causes serious damage to the surface of the metal material and leads to a decrease in service performance. Laser shock marking(LSM) allows the surface of the metal material to form a predetermined mark, which also improves the service performance accordingly.     

Development of millimeter wave integrated circulator based on barium ferrite

The development of telecommunications networks requires low-cost microwave and millimeter waves integrated devices. Among the microwave devices based on the non-reciprocity of ferrites, circulators are the most important. A typical use of circulators is in communication equipment (mobile phone and low power radar detection). Their operation allows to combine emission and detection using the same antenna. This work concerns the characterization of barium hexaferrite sputtered films and the device integration for the development of an integrated circulator working at a frequency of 40 GHz.     

Copper oxide as a sintering agent for barium titanate based ceramics

The purpose of this work was to study the effect of CuO as a versatile sintering agent for BaTiO₃ based ceramics. The response is shown to exist in three directions. Firstly, as liquid-phase former at comparatively low temperatures. Hence, the influence of various CuO-based flux formers on the shrinkage behaviour and the microstructure development of the ceramics was investigated. Secondly, the aptitude as an internal susceptor for secondary phase initiated microwave sintering. The use of CuO as a lossy secondary phase leads to an accelerated microwave heating of the ceramics. Thirdly, the addition of CuO to BaTiO₃ powders with Ba-excess results in a phase transition cubic hexagonal at about 1300°C, which is a indication for the incorporation of Cu²⁺ ions into the BaTiO₃ lattice at Ti sites under this conditions.     

Thermal expansion of solid solutions based on calcium and barium fluorides

The thermal expansion of the Ca_0.90Y_0.10F_2.10, Ca_0.97Yb_0.03F_2.03, Ca_0.97Co_0.03F_2.00, Ba_0.70La_0.30F_2.30, and Ba_0.80Nd_0.20F_2.20 solid solutions has been studied experimentally from below liquid-nitrogen temperature to room temperature. The results demonstrate that both the iso- and heterovalent dopants have a weak effect on the linear thermal expansion coefficient of the fluorite-structure crystals.     

基于功能尺寸最短路径的零件尺寸标注模式的设计

机械零件的尺寸标注模式有多种.尺寸标注模式影响着机械产品的精度和制造成本.为获得零件尺寸合理的标注模式,建立了包含零件尺寸标注所有可能模式的装配尺寸联系路径图;以满足装配体功能尺寸形成路径最短为目标,基于装配尺寸链最短路径原则和最短路径问题的求解,通过2种方法建立了装配体功能尺寸最短路径生成树.功能尺寸最短路径生成树确...     

一种基于区域标记的虹膜内边缘定位新算法

提出了一种新颖简单的虹膜内边缘（瞳孔）定位算法。首先，采用Soble边缘检测算子和形态学变换进行边缘检测；然后，利用区域标记法为边缘检测后形成的各连通成分赋予相应的灰度值，并利用直方图的方法分离出瞳孔区域；最后，采用投影的方法进行瞳孔的定位，实验结果表明，文中提出的方法能够准确地进行虹膜内边缘定位。     

基于SFC的上位机控制程序设计研究

介绍了用PLC的编程语言标准之一的SFC(顺序功能图)进行上位机控制部分程序的设计与编程,分析了程序设计与编程的可行性以及采用这种方法的优点,并对SFC用于上位机控制程序出现的死等问题提出了解决方案,生产实践证明,将SFC的编程思想用于上位机控制程序的设计与编程完全可行而且可以极大地提高上位机编程的效率和效果。     

Effects of barium dissolution on dispersing aqueous barium titanate suspensions

Dissolution of barium ion and its effect on dispersion behavior of aqueous barium titanate suspensions at various pH values have been investigated. The amount of leached barium ion decreases with increasing pH value. The dissolution of barium ion also causes an increase in pH value of suspension, but the change decreases with increasing initial pH value. The iso-electric point (IEP) of leached barium titanate powder increases with increasing leaching pH value and solid loading as well. The dissolution of barium ion enhances the colloidal stability of aqueous barium titanate suspension, in agreement with zeta potential measurement.     

Synthesis of single-crystalline perovskite barium titanate nanorods by a combined route based on sol-gel and surfactant-templated methods

The single-crystalline perovskite barium titanate nanorods were successfully synthesized by a combined route based on sol-gel and surfactant-templated methods at low temperature. The synthesis was accomplished by using barium acetate (Ba(CH₃COO)₂) and tetrabutyl titanate (Ti[O(CH₂)₃CH₃]₄) as the starting materials and laurylamine as the surfactant, respectively. Well-isolated single-crystalline cubic perovskite BaTiO₃ nanorods with diameters ranging from 20 to 80 nm and lengths reaching up to > 10 μm can be easily fabricated by this route. The crystal form and morphology of the nanorods were characterized by X-ray diffraction, TEM and HRTEM. The mechanism of the formation of the single-crystalline cubic perovskite BaTiO₃ nanorods was discussed based on the theory of oriented attachment.     

Sequential screening procedure based on individual misclassification error

A one-sided sequential screening procedure based on the Individual Misclassification Error (IME) is developed. The generalized formulas for any Sequential Screening Procedure (SQSP) with r stages are derived under the assumption of a multivariate normal distribution. Total Inspection Cost (TIC), Average Outgoing Quality (AOQ) and Producer's Risk (PR) are used as the criteria for selecting the optimal allocation. An example with four screening variables allocated into single-stage, double-stage and triple-stage sequential screening procedures (SSP, DSP and TSP) is illustrated using the derived generalized formulas to search for the best allocation.     

Thresholding procedure with priors based on Pareto distributions

In this paper, we consider wavelet thresholding rules within a Bayesian framework. The prior imposed on the wavelet coefficients is based upon a Pareto distribution. We introduce weak Besov spaces that enable us to measure the sparsity of each estimated signal. At first, we establish a relationship between the parameters of the prior and the parameters of the weak Besov space in which the realizations built from the prior lie. Subsequently, we exhibit a thresholding rule which threshold at each resolution level depends on the prior parameters. It is compared to deterministic classical thresholding procedures (VisuShrink and SureShrink) but also to efficient Bayesian thresh olding algorithms.     

A process monitoring procedure based on a surrogate variable for dichotomous performance variable

A monitoring procedure using a surrogate variable is proposed for a process with a binary performance variable. Using the procedure, every item is inspected on a surrogate variable. When an item is rejected, the latest number of consecutively accepted items up to this point is compared with a predetermined number, r, to decide whether to stop the process for an investigation. The conditional distribution of the surrogate variable given the performance variable is assumed to be normal. A cost model is developed, which incorporates costs of inspection, misclassification, investigation, opportunity, and correction. We develop methods of finding the optimum r value and screening limit and analyze the effects of cost parameters on the optimal solution.     

应用光纤传感器和旋转编码器的印刷品在线标废系统设计

实现产品由人工离线检测变为实时在线检测对企业具有重大意义。本系统利用单片机控制技术、光纤传感器探测技术和旋转编码器测距技术，实现了对印刷品的实时在线标废。本文从控制系统方案论证、传感器选型、硬件配置、软件开发等方面作了介绍。经过长期运行，证明该系统高效、可靠。     

An efficient integration procedure for linear dynamics based on a time discontinuous Galerkin formulation

This work presents an effective procedure devised to implement the time discontinuous Galerkin method for linear dynamics. In particular, the method with piecewise linear time interpolation is considered. The procedure is based on a simple and low-cost iterative scheme, which is designed not as a mere solution algorithm, but rather as a method to generate improved approximations to the exact solution. The corrected solutions inherit the desired stability and dissipative properties from the target solution, while accuracy is improved by iterations. Indeed, no more than two iterations are shown to be needed. The resultant algorithm leads to remarkable computational savings and can be easily implemented into existing finite element codes. Numerical tests confirm that the present procedure possesses many attractive features for applications to dynamic analysis. The authors acknowledge partial support by the Italian Ministry for Education, University and Research (MIUR, Cofin 2000) and partial support by the University of Bologna (Progetto RFO, ex-quota 60%, e.f. 2002). The computing facilities were provided by the Laboratory of Computational Mechanics (LAMC), DISTART, Università di Bologna, and the Laboratory of Computational Mechanics (LAMC), DIMC, Università di Modena e Reggio Emilia.     

A reconstruction procedure for microwave nondestructive evaluation based on a numerically computed Green's function

This paper describes a new microwave diagnostic tool for nondestructive evaluation. The approach, developed in the spatial domain, is based on the numerical computation of the inhomogeneous Green's function in order to fully exploit all the available a priori information of the domain under test. The heavy reduction of the computational complexity of the proposed procedure (with respect to standard procedures based on the free-space Green's function) is also achieved by means of a customized hybrid-coded genetic algorithm. In order to assess the effectiveness of the method, the results of several simulations are presented and discussed.     

Effect of barium on the structure and dielectric properties of multicomponent ceramics based on ferroelectric relaxors

High-density ceramic samples of mPb(Mg_1/3Nb_2/3) · yPb(Zn_1/3Nb_2/3) · nPb(Ni_1/3Nb_2/3) · xPbTiO₃ (m = 0.4541, y = 0.0982, n = 0.1477, x = 0.3) solid solutions, unmodified and barium-modified, with the composition lying in a morphotropic phase region, have been prepared by a conventional ceramic processing technique. We demonstrate that barium substitution for 5% of the lead on the A site allows one to obtain ceramics containing no pyrochlore phase. Modification with barium shifts the solid solution from the morphotropic to a tetragonal phase region. In addition, barium doping increases the average grain size of the ceramic from 2–3 to 3–4 μm and changes the type of fracture from intergranular to mixed (intergranular and transgranular). Modification with barium increases the relative dielectric permittivity ?/?₀ (at E = 0) of the material by more than a factor of 2 (from 4300 to 9100). We conclude that materials based on the ceramics studied can find practical application and examine ways of further improving their piezoelectric performance.     

A study on the behaviour of M-type barium hexagonal ferrite based microwave absorbing paints

This paper deals with development of single and double-layer microwave absorbing paints using Mn-substituted barium hexagonal ferrite. The comparative studies of both theoretical and experimental results at Ku band have been reported. It has been found that the single layer absorbing paint exhibits peak absorption of 12.3 dB at 17.4 GHz for a thickness of 1.12 mm. Double layer absorbing paint with each layer of different composition of ferrite gives a broad band characteristics, but at the cost of lowered absorption.     

An experimental-mechanics dynamic measurement procedure based on computer vision techniques

This paper describes a computer-vision based methodology for non-contact measuring of mechanical system movements. This methodology consists of frame-to-frame processing of video images corresponding to pictures acquired from vibrating structures. The main hardware and software tools are described here. Some benchmark tests are also shown so as to demonstrate the accuracy of the measurement methodology, Finally, perspectives of future developments and applications are discussed.     

基于“NTN”校准法的相位解卷绕技术

基于“NTN”校准理论,分析了“NTN”校准法中的相位卷绕问题及其带来的误差.提出了适用于“NTN”校准法的相位解卷绕技术,给出了使用相位解卷绕技术的“NTN”校准法的计算机仿真结果.