基于贝叶斯方法无损识别20钢高温时效状态

以 2 0钢高温时效组织形态为研究对象 ,依据贝叶斯判别原则 ,通过评价超声回波信号特征参数 ,建立样品分类识别判据 ,以待测样品的特征信息验证判据的可靠性 ,有效识别率不低于90 %。     

Pseudocapacitance properties of AC/LiNi1/3Co1/3Mn1/3O2 asymmetric supercapacitor in aqueous electrolyte

NH₂NH₂·H₂O which was used as controlling agent was applied to prepare the precursor Ni_1/3Co_1/3Mn_1/3(OH)₂ in the hydroxide co-precipitation method. The precursor was used to synthesize LiNi_1/3Co_1/3Mn_1/3O₂. The samples were characterized by XRD, XPS and SEM. It has been found that sintered sample at 800 °C for 16 h is considered as the optimal synthetic condition. The LiNi_1/3Co_1/3Mn_1/3O₂ was used as positive electrode and the activated carbon as negative electrode of the asymmetric supercapacitor. The electrochemical capacitance performance was tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge. The results indicate that species of aqueous electrolyte, current density, scan rate and potential limit, etc. have influence on the capacitance property of AC/LiNi_1/3Co_1/3Mn_1/3O₂ supercapacitor. The initial discharge specific capacitance of 298 F g^?1 was obtained in 1 mol L^?1 Li₂SO₄ solution within potential range 0–1.4 V at the current density of 100 mA g^?1 and was cut down less than 0.058 F g^?1 per cycling period in 1000 cycles. The asymmetric supercapacitor exhibited a good cycling performance.     

Analytical performance of the Tandem-R free PSA immunoassay measuring free prostate-specific antigen

The analytical performance of the Tandem-R free PSA assay available from Hybritech Inc. was evaluated. Comparison of recoveries of purified free (unbound) prostate-specific antigen (PSA) diluted in female serum in the Tandem-R free PSA assay and the Tandem-R (total) PSA assay demonstrated a link in calibration between the assays and an accurate determination of percent free PSA. The cross-reactivity of the assay to purified PSA-alpha 1-antichymotrypsin was determined to be < 1%. The minimum-detectable concentration was < 0.05 microgram/L. The within-run and between-day CVs were < or = 5% for samples with > 0.3 microgram/L free PSA. Dilution and recovery showed no significant deviations from linearity across the assay range. The assay was insensitive to interference from blood components. The Tandem-R free PSA kit was shown to be an accurate, precise, and reliable assay for the measurement of free PSA.     

High-temperature Raman study in CVD diamond

Measurements of the Raman spectra in chemical vapour deposition (CVD) diamond films at temperatures up to 1200 K are presented. Specifically, the evolution of Raman line position, line width, and intensity were monitored as a function of heating time. The red shifting and the line width broadening of CVD diamond's Raman line with temperature are very similar to that of natural diamond's. However, the detailed temperature dependence of Raman line width depends on the orientation of the CVD diamond crystal and the ambient gas used during thermal treatment. Since the CVD diamond usually exhibited a broader Raman spectra than natural diamond, the evolution of the line width upon heating is thus expected to depend on the origins and the annealing effects of the residual stress. For (111) CVD diamond subjected to annealing in air at 973 K, the line width decreased by more than one wavenumber while the line intensity increased by more than an order of magnitude before it decreased subsequently. In contrast, there is hardly any observable changes of the line width for (100) CVD diamond heated in air at 1173 K. Measurements conducted in He versus in air suggested that the reduction of the non-diamond carbon phase (therefore, the reduction of stress) is likely due to oxidation, which occurs more readily in (111) than in (100).     

A high-frequency shear device for testing soft biological tissues

Accurate mechanical property data obtained at large shear deformations and high frequencies are a fundamental component of realistic numerical simulations of soft tissue injury. Although many commercial systems exist for testing shear properties of viscoelastic materials with properties similar to soft biological tissue, none are capable of determining properties at high loading rates necessary for modeling soft tissue injury. Previous custom shear testing systems, though capable of high-frequency loading, indirectly measure tissue properties by using analytical corrections for inertial effects. To address these limitations, a new custom designed oscillatory shear testing apparatus (STA) capable of testing soft biological tissues in simple shear has been constructed and validated. Through a proper selection of sample thickness, direct measurement of material properties at high frequencies is achieved mechanically without analytical inertial adjustments. The complex shear modulus of three mixtures of silicone gel with viscoelastic properties in a range similar to soft biological tissue was characterized in the STA over a dynamic frequency range of 20-200 Hz and validated with a commercially available solids rheometer. The frequency-dependent complex shear modulus measurements of the STA were within 10% of the rheometer measurements for all mixtures over the entire frequency range tested. The STA represents substantive improvement over current shear testing methods by providing direct measurement of the shear behavior of soft viscoelastic material at high frequencies. Mechanical property data gained from this device will provide a more realistic basis for numerical simulations of biological structures.     

Low-power compact 2×2 thermooptic silica-on-silicon waveguideswitch with fast response

5-mm-long and 50-μm-wide thermooptic waveguide 2×2 Mach-Zehnder interferometer (MZI) switches with multimode interference (MMI) couplers have been realized in silica-on-silicon. The use of diffused square waveguides with a separating trench results in low heating power of 110 mW for π phase shift and short rise and fall times of 150 and 180 μs, respectively     

井下工具零件应力分析及其软件设计

针对井下工具零件结构复杂、形状怪异，且多为非标准件和非通用件，利用现行手册和常规分析方法难以进行应力分析的情况，依照这类工具零件的力学特征将其分为七大类进行应力分析，并编制了应力分析软件。在编制软件过程中，恰当地选择了软硬件环境和菜单技术，合理地设计了总体框图和分割了屏幕，使得软件具有友好的用户界面。