488天然气发动机的模拟计算

拟将一台CA4G22汽油机改为天然气专用发动机，为此对不同的技术方案进行了模拟计算。计算结果表明，采用增压中冷稀燃方案与理论空燃比方案相比，可以取得很好的动力性与经济性。     

舌形挡板变截面涡轮（VGT）的研究

由模拟试验得到的舌形ＶＧＴ蜗壳内的流动模型和进出口的速度系数，为该产品的设计和结构优化提供了理论依据。在匹配试验中总结了多种效应的相互影响和渗透，提示了舌形ＶＧＴ的发展前景。     

支持向量机模型在渗流监测中的应用

提出了基于一种支持向量机(SVM)的渗流监测方法。该方法采用结构风险最小化原则，能够在对小样本学习的基础上，对其他样本进行快速、准确的拟合预测，具有更好的泛化性能和精度，减少了对经验的依赖。在算例中，基于SVM的非线性特点，根据土石坝的实测资料建立了渗流监测模型，为水头预报和安全监测奠定了基础。     

基于一种新的优化方法的水平轴风力机风轮设计软件

提出了一种用于水平轴风机风轮设计的软件。该软件的主要目的是为风力机设计者提供一种灵活的集成设计环境，其核心是一个水平轴风机的气动优化过程。该过程基于一种改进的叶素理论，它采用一个有限叶片的旋涡系，因此叶片数量的影响被考虑进行并可得到更精确的气动力。     

One-step and cost-effective synthesis of micrometer-sized saw-like silver nanosheets by oil/water interfacial method

One-step synthesis of silver saw-like nanosheets was introduced by using aqueous AgNO₃ and benzene-soluble p-phenylenediamine (pPD). Based on the X-ray diffraction pattern and selected-area electron diffraction pattern, the silver was single crystal. As indicated by Scanning Electron Microscopy, Transmission Electron Microscopy and the auxiliary characterization by Fourier transform infrared and Raman Spectroscopy, the nanosheets are ~ 20 μm in edge length and are coated by poly(p-phenylenediamine) (PpPD) thin films. The role of oil/water interface and PpPD on the formation of sheet-like morphology was analyzed. This method is facile and cost-effective.     

Ionothermal/hydrothermal synthesis of the ternary metal chalcogenide ZnIn2S4

The ternary metal chalcogenide ZnIn₂S₄ was synthesized through the ionothermal/hydrothermal method using the ionic liquid [Bmim][BF₄]. The crystal structure and surface chemical state of the product were confirmed by X-ray diffractometry and X-ray photoelectron spectroscopy. A small amount of water was essential for the obtaining of yellow ZnIn₂S₄ product. ZnIn₂S₄ with a hexagonal phase was obtained in a wide range of [Bmim][BF₄]:water ratios of 9.3 ml:(0.1–5 ml). The size and morphology of the synthesized samples were strongly affected by the aid of [Bmim][BF₄], the amount of water, the zinc source, reaction temperature, and reaction time. The ZnIn₂S₄ showed different visible light absorption ranges when the water content of the reaction mixture was varied.     

Some Observations on the Performance of the Signal Matching Technique in Assessment of Pile Integrity

The pulse-echo method is commonly used to assess pile integrity in a nondestructive way. One of the strategies for detecting relative variation in pile impedance is to analyze the wave reflections from the anomalies based on the 1-D stress wave theory. In current practice, however, several difficulties remain to be resolved in interpreting the wave patterns. Firstly, due to possible three-dimensional (3-D) behavior near the source and dispersion behavior far from the source, 1-D stress wave theory is not always applicable in analyzing the reflections from the anomalies. Secondly, reflections can be produced continuously along the shaft due to the pile-soil interaction, so that the reflection patterns are highly correlated to those from the pile body in complex layered soil profiles, and thus it is generally difficult to distinguish whether the reflections are produced by pile anomalies or by the changes in the soil profiles. In this paper, actual wave characteristics are analyzed based on numerical simulations and guided wave theory, the conditions for 1-D approximation are suggested, and the a method for uncoupling the soil resistance and the pile impedance effects is presented. The evaluation of pile integrity can be improved with help of the 1-D based signal matching technique. The technique is applied to experiments conducted on model piles, test piles for accreditation of pile inspectors, and routine in-situ piles. The results show that 1-D stress wave theory is approximately applicable in analyzing the reflections from deep anomalies under certain limited conditions, and the soil resistance and the pile impedance effects can be effectively uncoupled by relating the pile-soil interaction to the pile radius and the properties of the surrounding soils.     

Dielectric and piezoelectric properties of Bi<Subscript>0·5</Subscript>(Na<Subscript>0·82</Subscript>K<Subscript>0·18</Subscript>)<Subscript>0·5</Subscript> TiO<Subscript>3</Subscript>-LiSbO<Subscript>3</Subscript> lead-free piezoelectric ceramics

The (1−x)Bi_0·5(Na_0·82K_0·18)_0·5TiO_3−x LiSbO₃ (x = 0−0·03) lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method and the effect of LiSbO₃ addition on microstructure and electrical properties of the ceramics was investigated. The results of XRD measurement show that Li⁺ and Sb⁵⁺ diffuse into the Bi_0·5(Na_0·82K_0·18)_0·5TiO₃ lattices to form a solid solution with a pure perovskite structure. The LiSbO₃ addition has no remarkable effect on the crystal structure. However, a significant change in grain size took place. Simultaneously, with increasing amount of LiSbO₃, the temperature for a antiferroelectric to paraelectric phase transition clearly increases. The piezoelectric constant d ₃₃ and the electromechanical coupling factor k _p show an obvious improvement by adding small amount of LiSbO₃, which shows optimum values of d ₃₃ = 175 pC/N and k _p = 0·36 at x = 0·01.     

Reduction of hexavalent chromium by Pannonibacter phragmitetus LSSE-09 stimulated with external electron donors under alkaline conditions

A novel Cr (VI) resistant bacterial strain LSSE-09, identified as Pannonibacter phragmitetus, was isolated from industrial sludge. It has strong aerobic and anaerobic Cr (VI)-reduction potential under alkaline conditions. At 37 °C and pH 9.0, growing cells of strain LSSE-09 could completely reduce 100 and 1000 mg L(-1) Cr (VI)-Cr (III) within 9 and 24h, respectively under aerobic condition. Resting cells showed higher anaerobic reduction potential with the rate of 1.46 mg g(-1)((dry weight))min(-1), comparing with their aerobic reduction rate, 0.21 mg g(-1)min(-1). External electron donors, such as lactate, acetate, formate, pyruvate, citrate and glucose could highly increase the reduction rate, especially for aerobic reduction. The presence of 3000 mg L(-1) acetate enhanced anaerobic and aerobic Cr (VI)-reduction rates up to 9.47 mg g(-1)min(-1) and 4.42 mg g(-1)min(-1), respectively, which were 5 and 20 times faster than those without it. Strain LSSE-09 retained high activities over six batch cycles and NO(3)(-) and SO(4)(2-) had slightly negative effects on Cr (VI)-reduction rates. The results suggest that strain LSSE-09 has potential application for Cr (VI) detoxification in alkaline wastewater.     

基于边缘探测的密集颗粒图像分割方法

针对密集的颗粒图像提出了一种基于边缘探测的颗粒分割方法.该方法采用分块自适应的边缘检测算法实现对图像的边缘检测,并采用形态学方法去除边缘噪音;采用分水岭算法对图像进行初步分割,根据分割区域自动选取种子点,并利用区域面积对种子点进行修正,然后从种子点发射探测线探测边缘位置,记录边界点,通过判断机制判别出由于边缘不完整或噪...