一种车辆状态通用自动监测装置设计与实现

当前装备车辆底盘数据大都通过仪表盘进行显示,而没有对数据进行采集和存储,造成对车辆的基本状态无法进行有效的评估和故障趋势分析;针对这种情况,设计一种对车辆底盘运行参数进行采集和存储的装置,通过一个通用的多PIN接口与车辆仪表盘信号线相连,采用高速AD芯片、高速主控芯片和RS485通讯接口实现对仪表盘接线输出信号的采集、计算与数据的传输存储;应用表明,此装置解决了多种车辆底盘参数的采集记录问题,具有广泛的推广应用价值。     

故障注入技术在机载计算机模拟量采集中的应用

近年来航空武器的功能性能快速提高,机载计算机处理能力也越来越强。接口模块作为处理多种接口信号的重要部件,在机载计算机中起着至关重要的作用。文中结合故障注入技术,在以往常用模拟量采集电路基础上,设计了模拟量激励产生电路,实现模拟量采集电路的故障注入,结合测试软件完成模拟量采集电路的检测,达到提高机载计算机的测试性的目标。     

Correlation of fluctuation field and temperature coefficient of coercivity in a CoCrPtB thin film

The effect of the ratio of fluctuation field (H_f) to coercivity (H_c) on the temperature coefficient of coercivity [α(H_c)] was investigated for Co₅₅Cr_15.5Pt₂₈B_1.5/Co₆₃Cr₃₇/Cr, Co₆₉Cr₁₉Pt₉Ta₃/Cr, and Co₈₆Cr₁₀Ta₄/Cr thin films (longitudinal recording media) with very small average grain volume (V_phy). α(H_c) increases markedly with increase in temperature between near 250 and 350 K for Co₅₅Cr_15.5Pt₂₈B_1.5/Co₆₃Cr₃₇/Cr thin films. α(H_c) is approximately proportional to the ratio H_f/H_c for all thin films, as in the case of advanced data backup tapes prepared from ultrafine particles. α(H_c) and the ratio H_f/H_c increase as V_phy decreases. Smaller H_f/H_c values are necessary for small α(H_c) values, which is very important for the thermal stability of high-density recording media with very small V_phy.     

飞机跑道胶痕的自动识别系统设计与实现

为了减轻机场跑道除胶工作人员的劳动强度,提高除胶工作效率,文章提出了一种基于机器视觉的胶痕自动查找和识别方法,设计了基于ARM单片机控制的图像无线采集和基于PC机控制的图像接收、图像预处理和图像识别系统。文章通过分析预处理后的数据特点,确定了基于细胞神经网络算法的胶痕识别算法,然后在MATLAB仿真环境下确定了该算法的最优模型和参数,最后在Visual C++ 6.0环境下完成了该算法的程序编译,调试并完成了对胶痕的自动识别过程。理论仿真和程序测试的结果证明了文章提出的方法在胶痕自动识别系统中的可行性,也为机场特种设备的无人化和智能化提供了参考。     

Valence states of copper atoms in cuprates determined from the change in the electron-capture constant of 64Cu

The change in the ⁶⁴Cu electron-capture constant for the compounds Cu₂O, YBa₂Cu₃O₇, YBa₂Cu₃O₆, Nd₂CuO₄, Nd_1.8Ce_0.2CuO₄, La₂CuO₄, La_1.7Sr_0.3CuO₄, Tl₂Ba₂CaCu₂O₈, and Bi₂Sr₂CaCu₂O₈ has been measured. It is concluded that the copper in YBa₂Cu₃O₇, Nd₂CuO₄, La₂CuO₄, La_1.7Sr_0.3CuO₄, Tl₂Ba₂CaCu₂O₈, and Bi₂Sr₂CaCu₂O₈ is exclusively divalent, whereas in Cu₂O, YBa₂Cu₃O₆, and Nd_1.8Ce_0.2CuO₄ univalent copper is present. Fiz. Tverd. Tela (St. Petersburg) 39, 1793–1794 (October 1998)     

Photoelectron spectra of ethylene and of the six deuterated derivatives

The photoelectron spectra of C₂H₄ and of six deuterated molecules of ethylene — C₂D₄, C₂D₃H, C₂H₃D, cis-C₂H₂D₂, trans-C₂H₂D₂ and gem-C₂H₂D₂ — have been recorded with the 584-Å resonance line of He. The adiabatic ionization potentials of the X²B_3u and the ²B_3g states of the seven isotopic components have been determined with an accuracy of about 7 meV. The ionization potentials of the other excited electronic states have been measured with a lower accuracy owing to a less well defined onset. The measured ionization potentials of C₂H₄ are 10.514 eV, 12.431 eV, 14.4₃ eV, 15.7₄ eV and 18.7 eV. The vibrational structure of the first electronic band shows that the two normal modes ν₂ (symmetric CC stretching) and ν₃ (symmetric HCH bending) are excited simultaneously. The measured vibrational frequencies show no abnormal isotopic effect if the assignment given in the literature for the ν₂ and ν₃ modes in C₂H₄⁺ are reversed and if a stronger excitation of the ν₃ symmetric bending mode in the least deuterated compounds is assumed. The vibrational modes most strongly excited in the second and third electronic bands are ν₁ (symmetric CH stretching) and ν₃, and in the fourth band ν₃.     

Structure of Artificial Grain Boundaries in Sapphire Bicrystals with Intermediate Layers

The structure of the artificial grain boundaries in Al₂O₃ bicrystals withY₃Al₅O₁₂ and Y-stabilizedZrO₂ (Y-ZrO₂) intermediate layers was studiedwith high resolution electron microscopy, electron diffraction and energydispersive X-ray analysis. TheY₃Al₅O₁₂ intermediate layer wasfound to be polycrystalline with three different orientation relationshipsbetween the ₂O₃ and theY₃Al₅O₁₂. The structure of theY₃Al₅O₁₂/₂O₃ interfaces is described.Also₂O₃ bicrystals with an Y-ZrO₂/₂O₃/Y-ZrO₂/₂O₃/Y-ZrO₂intermediate layer, prepared at two different temperatures, werestudied.Recry stallization of the intermediate layers occurred during thesolid phase intergrowth of the ₂O₃ bicrystalsparts and only an Y-ZrO₂ layer was found as intermediatelayer. The misorientation between the consecutive Y-ZrO₂grains was less than 1.5°. Misfit dislocations and atomic height stepsdecorate the Y-ZrO₂/₂O₃interface.     

Effect of conduction band nonprabolicity on the Rashba spin splitting of AlGaN/GaN QWs

By using the perturbation expansion method and self-consistent iterative method, we evaluate the effect of the conduction band nonprabolicity on the wave vector (k_t) dependent Rashba coefficient (α) and nonlinear Rashba spin splitting (ΔE) in the Al_0.5Ga_0.5N/GaN quantum well (QW). The effective mass (energy) under the first order approximation m_t1 (E_k1) is in proximity to the iterative result m_tp (E_kp) and m_t1>m_tp, E_k1<E_kp, showing the higher order contributions to m_t (E_k) are small. The sign of the nonparabolic correction to E_k is just opposite to that of the correction to m_t. The increase of α and ΔE due to the conduction band nonparabolicity reaches about 3% at k_t=1 nm⁻¹. Around the left heterointerface, the probability density is high and E_k0>E_kp>E_k1, so α₀<α_p<α₁, ΔE₀<ΔE_p<ΔE₁. With increasing k_t, α decreases, and ΔE increases slowly. For small k_t, α₀ (ΔE₀), α₁ (ΔE₁) and α_p (ΔE_p) are nearly the same. While for large k_t, the difference between α₀ and α₁ (α_p) increases rapidly, but the difference between ΔE₀ and ΔE₁ (ΔE_p) increases slowly.     

Some tips on the decomposition of tensor product representations of compact connected lie groups

Let ?₁, ?₂, ?₃, ?₄ be irreducible representations of a compact connected semisimple Lie group G with highest weights Λ₁, Λ₂, Λ₃, Λ₄, respectively. Let ?₁?₂ (resp. ?₃?₄) be irreducible representations of G with highest weights Λ₁·Λ₂ (resp. Λ₃·Λ₄). It is assumed that one knows the Clebsch-Gordan series of ?₁??₃ and ?₂??₄ (resp. of S²?₁, S²?₂, A²?₁ and A²?₂). Then we formulate a result (Theorem 2) which gives information on the decomposition of ?₁?₂??₃?₄ (resp. of S²(?₁?₂) and A²(?₁?₂)). Though this result is not complete, it is useful because it delivers the information very quickly and in a very simple manner.     

Kinetic study on effect of novel cationic dimeric surfactants for the cleavage of carboxylate ester

Kinetic study has been performed to understand the reactivity of novel cationic gemini surfactants viz. alkanediyl‐α,ω‐bis(hydroxyethylmethylhexadecylammonium bromide) C₁₆‐s‐C₁₆ MEA, 2Br^? (where s = 4, 6) in the cleavage of p‐nitrophenyl benzoate (PNPB). Novel cationic gemini C₁₆‐s‐C₁₆ MEA, 2Br^? surfactants are efficient in promoting PNPB cleavage in presence of butane 2,3‐dione monoximate and N‐phenylbenzohydroxamate ions. Model calculation revealed that the higher catalytic effect of ethanol moiety of gemini surfactants (C₁₆H₃₃N⁺ C₂H₄OH CH₃ (CH₂)_S N⁺ C₂H₄OH CH₃C₁₆H₃₃, 2Br^?, s = 4, 6) is due to their higher binding capacity toward substrate. This is in line with finding that binding constants for novel series of cationic gemini surfactants are higher than conventional cationic gemini (C₁₆H₃₃N⁺(CH₃)₂(CH₂)_SN⁺(CH₃)₂C₁₆H₃₃, 2Br^?, s = 10, 12), cetyldimethylethanolammonium bromide and zwitterionic surfactants, i.e. C_nH_2n+1N⁺Me₂ (CH₂)₃ SO₃^? (n = 10; SB3‐10). The fitting of kinetic data was analyzed by the pseudophase model. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of some additions on the sinterability and magnetic properties of barium hexaferrite

The effect of additions on the densification of previously prepared stoichiometric barium hexaferrite, during the initial and intermediate stages of sintering, as well as on the coercivity and remanence were studied. The effect of non-stoichiometry, SiO₂, Al₂O₃, Cr₂O₃, TiO₂, SnO₂, MnO₂, MgO, NiO and Bi₂O₃ is included.While SiO₂ and Bi₂O₃ form liquid phases that increase the density, Al₂O₃, Cr₂O₃ and MnO₂ form a limited solid solution and are generally beneficial when added in the proper amounts. At 1300 SiO₂ up to 0.55% and Al₂O₃ up to 1% gave better magnetic properties. On the other hand addition of TiO₂, MgO, NiO or SnO₂ has a deleterious effect.     

Molar extinction coefficients of solutions of some organic compounds

Molar extinction coefficients of aqueous solutions of some organic compounds, viz. formamide (CH₃NO),N-methylformamide (C₂H₅NO),NN-dimethylformamide (C₃H₇NO),NN-dimethylacetamide (C₄H₉NO), 1,4-dioxane (C₄H₈O₂₄), succinimide (C₄H₅NO₂) and solutions of acetamide (C₂H₅NO) and benzoic acid (C₇H₆O₂) in 1,4-dioxane (C₄H₈O₂) have been determined by narrow beam γ-ray transmission method at 81, 356, 511, 662, 1173 and 1332 keV. The experimental values of mass attenuation coefficients of these compounds have been used to calculate effective atomic numbers and electron densities. The additivity rule earlier used for aqueous solution has been extended to non-aqueous (1,4-dioxane) solutions.     

UV excimer laser photochemistry of hybrid organometallic compounds of gallium

The gas phase ultraviolet (UV) excimer laser induced photolysis of the gallium-alkyls Ga(t-C₄H₉) _n ^– (CH₃)_3–n (n=0, 1, 2, 3) was studied, using photolysis wavelengths of 308, 248, and 193 nm. The photofragments Ga, GaH, and GaCH₃ were detected by laser ionization time-of-flight mass spectroscopy, while the hydrocarbon products CH₄, C₂H₆, HC(CH₃)₃ and H₂C=C(CH₃)₂ were identified using Fourier transform infrared (FTIR) spectroscopy. The formation of the GaH photofragment, and a high olefin-to-alkane product ratio, for Ga(t-C₄H₉)₂(CH₃) and Ga(t-C₄H₉)₃ are interpreted to indicate a -hydrogen elimination process. However, -hydrogen elimination only occurs after fission of the weakest Ga-C bond, thus no -hydride elimination is observed for Ga(t-C₄H₉)(CH₃)₂. Detection of C₂H₆ for Ga(CH₃)₃ and Ga(t-C₄H₉)(CH₃)₂, but not for Ga(t-C₄H₉)₂(CH₃), shows that under our experimental conditions the formation of ethane is as a result of the reductive elimination of the methyl groups, and is not due to the recombination of two free methyl radicals.     

Effects of synthetic routes of Fe-urea complex on the synthesis of γ-Fe2O3 nanopowder

Maghemite (γ-Fe₂O₃) nanopowder was prepared by the thermal decomposition of Fe-urea complex ([Fe(CON₂H₄)₆](NO₃)₃) that was synthesized by various routes including wet and dry synthetic methods. Then the effects of synthetic routes of the [Fe(CON₂H₄)₆](NO₃)₃ on resulting iron oxide crystalline phases and their magnetic properties have been studied using X-ray powder diffraction (XRD) and magnetic measurements. The result of XRD shows that the iron oxide crystalline phases are strongly dependent on the synthetic routes of the [Fe(CON₂H₄)₆](NO₃)₃. When [Fe(CON₂H₄)₆](NO₃)₃ is synthesized in ethanol, thermal decomposition of the compound results in pure γ-Fe₂O₃. When [Fe(CON₂H₄)₆](NO₃)₃ is synthesized either by an aqueous synthetic method or by a dry synthetic method, however, thermal decomposition of the compound results in mixed phases of γ-Fe₂O₃ and α-Fe₂O₃. Magnetic measurements show that resulting iron oxide nanopowder exhibits a ferromagnetic characteristic with a maximum saturation magnetization (Ms) of 69.0 emu/g for the pure γ-Fe₂O₃ nanopowder.     

Magnetic properties of nanostructured MnZn ferrite

Mn_0.5Zn_0.5Fe₂O₄ nanoparticles (10-30 nm) have been prepared via mechanochemical processing, using a mixture of two single-phase ferrites, MnFe₂O₄ and ZnFe₂O₄. SQUID measurements (field-cooled magnetization curves and hysteresis loops) were performed to follow the mechanically induced evolution of the MnFe₂O₄/ZnFe₂O₄ mixture submitted to the high-energy milling process. The resulting single MnZn nanoferrite phase was characterized by SQUID (M-H curve), Faraday balance (M-T curve) and transmission electron microscopy. The magnetic characteristics of the mechanosynthesized material were compared with those of bulk Mn_0.5Zn_0.5Fe₂O₄. It was found that the saturation magnetization of nanostructured Mn_0.5Zn_0.5Fe₂O₄ (87.2 emu/g) is lower than that of the bulk Mn_0.5Zn_0.5Fe₂O₄, but, the Néel temperature of the sample (583 K) is higher than that of the bulk Mn_0.5Zn_0.5Fe₂O₄.     

The elastic behaviour of tetrahedral materials with vacant sites

As part of a study of defect tetrahedral structure compounds, the elastic constants of single crystal specimens of Hg₃Ga₂□Te₆ and HgIn₂□Te₄ have been measured between 77 K and room temperature using the pulse superposition technique. These compounds are included in the series HgTe, Hg₅In₂□Te₈, Hg₃In₂□Te₆ and HgIn₂□Te₄ and HgTe, Hg₅Ga₂□Te₈, Hg₃Ga₂□Te₆ where there is a progressive increase in the concentration of vacant sites. While the other compounds studied are cubic, HgIn₂□Te₄ has a tetragonal structure with a $\text{c}\text{a}$ ratio of 2.0. The components of the elastic stiffness tensor of this material at 77 K are (in units of 10¹¹ dyne cm^?2) C₁₁ = 4.31 C₁₂ = 2.54 C₄₄ = 2.14 C₃₃ = 4.47 C₁₃ = 2.18 C₆₆ = 2.41. In a cubic material C₁₁ = C₃₃, C₄₄ = C₆₆ and C₁₂ = C₁₃: the elastic behaviour of this tetragonal compound closely resembles that of a cubic material, as might be anticipated from its structure. This similarity is further illustrated by reference to the symmetry of phase velocity and Young's modulus surfaces. Examination of the elastic constants and reduced elastic constants of these compounds shows a regular trend, the elastic stiffness decreases as the number of vacant sites increases. There is an approximately linear relationship between the reduced bulk modulus and the number of sited vacancies.     

Discussion again of the magnetic and transport property of Ag-doped LaMnO3

Samples La_1−aAg_aMnO₃ (0.05?a?0.50) were sol–gel fabricated. A part of Ag was found to dissociate and run off the samples in sintering process when sintering temperature exceeds 700 °C, resulting in a composite of La_1−xAg_xMnO₃ and MnO₂/Mn₂O₃. The magnetic and transport properties of the composite have been studied. The sample with the nominal composition La_0.7Ag_0.3MnO₃ was found to show the greatest magnetoresistance in the sample group. Detailed analysis on average Mn valence reveals a composite of (La_0.985Ag_0.015MnO₃)_0.776[(MnO₂)_0.590(Mn₂O₃)_0.410]_0.224. Its MR ratio at room temperature exceeds 24% under a field of 1.8 T. A conductivity leap has been observed around a=0.30. It suggests a kind of field-induced fluctuation in percolation in the samples investigated.     

Comparison of the band alignment of strained and strain-compensated GaInNAs QWs on GaAs and InP substrates

We present a comparison of the band alignment of the Ga_1−xIn_xN_yAs_1−y active layers on GaAs and InP substrates in the case of conventionally strained and strain-compensated quantum wells. Our calculated results present that the band alignment of the tensile-strained Ga_1−xIn_xN_yAs_1−y quantum wells on InP substrates is better than than that of the compressively strained Ga_1−xIn_xN_yAs_1−y quantum wells on GaAs substrates and both substrates provide deeper conduction wells. Therefore, tensile-strained Ga_1−xIn_xN_yAs_1−y quantum wells with In concentrations of x0.53 on InP substrates can be used safely from the band alignment point of view when TM polarisation is required. Our calculated results also confirm that strain compensation can be used to balance the strain in the well material and it improves especially the band alignment of dilute nitride Ga_1−xIn_xN_yAs_1−y active layers on GaAs substrates. Our calculations enlighten the intrinsic superiority of N-based lasers and offer the conventionally strained and strain-compensated Ga_1−xIn_xN_yAs_1−y laser system on GaAs and InP substrates as ideal candidates for high temperature operation.     

Crystal structure analysis of novel complex hydrides formed by the combination of LiBH4 and LiNH2

Combination of LiBH₄ and LiNH₂ by ball milling forms the series of novel complex hydrides Li₂BNH₆, Li₃BN₂H₈ and Li₄BN₃H₁₀, depending on the combination ratios. The crystal structure of Li₄BN₃H₁₀ analyzed by synchrotron X-raydiffraction measurements is determined to be a cubic system (space group: I2₁3) with the lattice constant of a=10.673(2)Å. It should be emphasized that Li₄BN₃H₁₀ is an ionic crystal which is composed of a lithium cation Li⁺ and two different kinds of the complex anion [BH₄]^- and [NH₂]^-. These anions are located in the vertex and face-center of the cubic sub-lattice, and the lithium cation Li⁺ in the interstitial site between the anions, respectively. The other series of complex hydrides, Li₂BNH₆ and Li₃BN₂H₈, are also predicted to possess similar structures composed of a lithium cation Li⁺ and two different kinds of the complex anion [BH₄]^- and [NH₂]^-.     

Synthesis and regularities of combustion of acetoxymethylnitroamines. Impact sensitivity of secondary alkylnitroamines

The use of the nitrolysis of cyclic amines and of the direct synthesis from primary nitroamines made it possible to obtain acetates of methylolnitroamines of general formula AcO(CH₂NNO₂) _n R(n = 1–6). A number of high explosives, nitroamines, were synthesized: DNA ((CH₃NNO₂)₂CH₂), DMNA ((CH₃)₂NNO₂), DNA-2 ((CH₃NNO₂CH₂)₂), TRIS ((CH₃NNO₂CH₂)₂NNO₂), and TETRA ((CH₃NNO₂CH₂NNO₂)₂CH₂). The regularities of the combustion of the synthesized compounds were studied, and their characteristics were compared. Stress curve measurements were used to estimate the impact sensitivity of alkylnitroamines. A number of basic macroscopic characteristics of the nitroamines studied and nitroamine-ammonium perchlorate mixtures, including the heat of explosion. For comparison, the characteristics of regular high explosive are given.