7022铝合金搅拌摩擦焊焊接区的组织与力学性能

以厚度为10mm的7022铝合金为对象进行搅拌摩擦焊接试验,研究了搅拌摩擦焊工艺参数对接头组织和力学性能的影响.结果表明:焊接接头具有良好的力学性能,在搅拌头转速为400r/min、焊接速度为100mm/min时,7022铝合金的搅拌摩擦焊接头抗拉强度和屈服强度分别达615MPa和533 MPa,均超过了母材;焊接接头的显微硬度略低于母材;断口形貌分析表明,7022铝合金搅拌摩擦焊接件拉伸断裂为韧性断裂.     

改进的梯度向量正交投影声回波对消算法

在梯度向量正交投影算法的基础上,提出一种改进的梯度向量正交投影算法.改进算法归一化时变遗忘因子使其稳定性优于原算法.此外,在滤波器系数更新过程中,利用系统过去时刻信息,并引进批处理技术,在保持计算复杂度不变的同时提高了算法的抗噪性.仿真表明改进算法改善了声回波对消效果,且稳健性好.     

Load reduction sintering for increasing productivity and decreasing fuel consumption

The technical and economical indexes and the physical properties of load reduction sintering processes with the supporting stands of installation at different height levels (300, 350, and 400 mm) in a sintering bed were studied under the same conditions of raw material, bed height, and sintering parameters. Sintering pot tests with different bed heights and fuel ratios of the mixture with or without supporting stands were performed to decrease the fuel consumption. The airflow rate through the sintering bed was measured with an anemoscope fixed on the bed surface to reveal the effects of supporting stands. The utilization of load reduction sintering can improve the permeability of the sintering bed, and the airflow rate through the sintering bed is increased. When the stand height is half of the sintering bed, the productivity increases by 27.9%, and the drum index slightly decreases. Keeping at the same productivity level with normal sintering, the utilization of load reduction sintering can decrease the solid fuel consumption by 9.2%.     

赋Luxemburg范数的Musielak-Orlicz序列空间的局部β性质

给出了赋Luxemburg范数的Musielak-Orlicz序列空间lM的单位球面上的任意一点是β点的充分必要条件.作为推论给出了此空间具有局部β性质的判别准则.     

Precipitation behaviors of X80 acicular ferrite pipeline steel

The precipitation behaviors of X80 acicular ferrite pipeline steel were investigated by using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The results show that dendritic precipitates in the as-cast steel slabs precipitate mainly in grain boundaries, and these dendritic precipitates dissolve and re-precipitate to two kinds of carbonitrides: Ti- and Nb-rich (Ti, Nb)(C, N) carbonitrides during reheating. Four types of precipitates mainly exist in the hot rolled plate: Ti-rich carbonitrides resulted from the dendritic carbonitrides undissolved during the reheating process; Ti-rich carbonitrides re-precipitated along austenite grain boundaries during the reheating process; NbC carbides mainly heterogeneously nucleated on the small pre-existing Nb-rich carbonitrides in the hot rolling process; and NbC carbides precipitated on dislocations during hot rolling.     

烧结熔剂的活性度和显微结构研究

技术设计是技术研发的起点,其实质是人化自然的过程。关注技术设计过程中的伦理问题,是确保技术积极价值实现的关键。纳米制药技术设计的伦理问题主要表现为安全性设计、可持续性设计和社会发展性设计,其旨归是人文精神。纳米制药技术设计责任包括对人健康负责、对环境生态负责和对社会经济发展负责三重责任,其责任性质是利益相关者责任,即技术设计者责任、技术决策者责任、技术管理者责任和技术使用者责任。对纳米制药技术设计责任实施有效的责任控制需要建构协同的法律规范、伦理规约和管理制度。     

基于改进投影寻踪技术和模糊神经网络的未受精种蛋检测模型

考虑基于计算机视觉技术的未受精种蛋无损检测中特征参数之间关系的复杂性和模糊性等因素,提出了一种基于改进投影寻踪模型和模糊神经网络相结合,作为种蛋是否受精品质归属的决策系统.利用量子投影寻踪技术对种蛋图像的复杂形状特征向量进行提取降维,给出了计算最佳投影方向的一种改进量子遗传算法;并且利用模糊神经网络的自动学习决策推理规则,实现了种蛋是否受精品质归属的无损检测.结果表明:该模型速度快且稳定,精度高且鲁棒性好,简单易于实现,精度达到99.37％,满足实际检测要求.     

鄂尔多斯东缘煤储层渗透性主控因素分析与高渗区预测

在煤层气储层渗透性影响因素的分析基础上,通过煤层地应力、热演化程度、埋藏深度与渗透率的相关性分析,探讨渗透率的发育机理,认为煤储层渗透率是煤阶与地应力联合作用的结果,地应力控制煤储层割理开启程度和方向,改变储层的孔隙结构;煤岩热演化通过改变岩石力学性质来控制割理发育,二者共同控制煤储层割理的大小,进而影响煤储层渗透率的发育,而埋藏深度与渗透率相关性不强.选取煤层渗透率主控因素进行研究,以鄂尔多斯盆地东缘二叠系煤层气储层为例,利用多元回归分析的方法建立了“煤阶与地应力”渗透性二元预测模型,对研究区渗透率的发育情况进行了预测.研究表明,地应力控制了渗透率的分布,而煤岩热演化程度对渗透率分布起到一定的调节作用,煤层气储层高渗区主要分布在研究区斜坡带地应力松弛部位,而在应力相对集中深部煤储层为低渗区.     

Electrochemical biosensors and logic devices based on aptamers

Aptamers are molecular recognition elements with high specificity that are selected from deoxyribonucleic acid/ribonucleic acid (DNA/RNA) library. Compared with the traditional protein recognition elements,aptamers have excellent properties such as cost-effective,stable,easy for synthesis and modification. In recent years,electrochemistry plays an important role in biosensor field because of its high sensitivity,high stability, fast response and easy miniaturization. Through the combination of these two technologies and our rational design,we constructed a series of biosensors and biochips that are simple,fast,cheap and miniaturized. Firstly,we designed an adenosine triphosphate (ATP) electrochemical biosensor based on the strand displacement strategy. We can detect as low as 10 nmol/L of ATP both in pure solution and complicated cell lysates. Secondly,we creatively split the aptamers into two fragments and constructed the sandwich assay platform only based on single aptamer sequence. We successfully transferred this design on biochips with multiple micro electrodes (6×6) and accomplished multiplex detection. In the fields of biochips and biocomputers,we designed several DNA logic gates with electric (electrochemical) signal as output which paves a new way for the development of DNA computer.     

Google Earth-based dynamic visualization system for storm surge flood routing

To describe the dynamic process of flood routing intuitively and realistically when storm surge disaster occurs, a method for ArcGIS data and Google Earth （GE） data integration is proposed, which realizes the impor- ting and integrating of basic geographic information into GE. Based on SketchUp and AutoCAD software, three- dimension （3D） visualization of seawall and other tidal defense structures is achieved. By employing Microsoft Foundation Class Library （MFC）, the related system modules and storm surge flood routing dynamic visualization system are developed. Therefore, dynamic visualization of flood routing process and interactive query of sub- merged area and inundated depth are implemented. A practical application case study of Tianjin Binhai New Area provides decision-making support for coastal seawall planning and storm surge disaster prevention and reduction.