软对数周期天线的结构设计

软对数周期天线所使用的软索具有弯曲悬垂变形的特点,对于大尺寸天线可能导致集合线严重弯曲变形。通过对软索变形的理论分析,在每根振子末端点与软索连接点间增加一段合适长度的非金属振子补偿尾线,就可以克服软索悬垂的不利条件。有效地利用其特点,使天线集合线呈水平状态,振子呈垂直状态,实现天线的保形,从而满足电气要求。在材料的选择方面,特制电缆、特制软线和迪尼玛绳都非常适合工程的使用。     

沪蓉西高速公路拓宽软土地基高路堤施工技术

沪蓉西高速公路贺家坪连接线K2+710～K2+890段为软土地基上老路拓宽高路堤.半幅路基为稳定性较好的老路利用,而另半幅路基位于河谷冲击沉积的水田内,上部有3.0～6.5m的淤泥层,路堤最大填筑高度约40m.工后沉降、差异沉降、路堤失稳是本路堤质量控制的关键.介绍施工中采用抛石挤淤、开挖台阶、分层铺设土工格栅等措施综合处治措施,并加强稳定性和沉降动态监测.确保了路堤填筑质量和进度,保证了整个工程顺利完成.     

动力排水固结法软基加固效果数值分析

动力排水固结法是一个瞬态动力响应问题,其复杂性决定了地基土在夯击过程中的特性难以用常规的解析方法进行推证.采用FLAC3D软件对动力排水固结过程作数值模拟,并对动力排水固结法的有效加固深度及加固范围作分析.研究表明,动力排水固结法加固的主要范围是夯锤下方的椭球体区域,表现为竖向压缩,侧向挤压,有效加固深度和加固范围可由数值模拟较准确预测.     

Soft measurement of pulp suspension flow velocity based on wavelet transform

A soft measurement technique is presented, which the pulp suspension flow velocity (PSFV) can be obtained by analysis of pulp fibre consistency signal without using the flow sensor or flow meter. Doppler Effect in pulp fibre consistency signal, which is caused by the relative motion between pulp suspension flowing in pulp pipe and consistency sensor fixed in the pipe, is discovered on the basis of studying the structure of pulp suspension and the properties of pulp fibre consistency signal, and it is proved by wavelet transform (WT) in this paper. WT are used to analyse pulp fibre consistency signal based on Doppler Effect. PSFV can be determined by the average period of WT which is used to analyse pulp fibre consistency signal based on Doppler Effect. The corresponding tests indicate that the measurement technique is feasible with high precision and better dynamic characteristics.     

Micropatterning of Electrospun Polyurethane Fibers Through Control of Surface Topography

A novel technique was developed to control the deposition of electrospun polyurethane fibers using a silicone collector substrate patterned with soft lithography. This method can be used to control selective fiber deposition with broad pattern dimensions (50–500 µm) over a large area. The combination of ease of use, low cost, tunability, and generation of relatively large fiber mats available with this technique is expected to advance our ability to mimic the orientation and anisotropic properties of native tissues to generate improved tissue engineering scaffolds.

     

铝软钎焊剂的研究与制备

探究了铝软钎焊助焊剂中有机酸、有机胺、氟硼酸盐等对其焊接性能的影响。结果表明,铝助焊剂的最佳配方为:有机胺选用三乙醇胺和三乙烯四胺复配,占总含量的20%左右;有机酸选用水杨酸和己二酸复配,占总含量的3%左右;溶剂选用正丙醇和无水乙醇复配,占总含量的22%左右;树脂选用聚乙二醇400,占总含量的25%;活性剂选用氟硼酸锌、氟硼酸亚锡、氟硼酸铵和氟铝酸钾等,占总含量的40%左右;缓蚀剂选用苯并三氮唑,氟碳表面活性剂选用FSN-100。     

基于时空局部学习的集成自适应软测量方法

集成软测量方法已被广泛应用于流程工业关键质量参数实时估计。但是,常规集成建模方法在基模型构建过程中往往局限于挖掘样本之间的空间关系,忽略了样本间的时序关系,从而导致过程局部状态挖掘不充分、基模型间多样性不足等问题。其次,传统软测量方法由于缺乏自适应机制而无法有效处理过程时变特征,从而导致模型性能发生退化。为此,提出一种基于时空局部学习(STLL)的集成自适应软测量方法。该方法首先通过移动窗口、即时学习技术分别挖掘样本间的时序关系和空间关系,并采用统计假设检验实现冗余状态剔除,进而构建多样性的时空局部高斯混合回归(GMR)模型。然后,基于在线选择性集成策略实现局部预测结果的自适应融合。此外,引入双重自适应机制以缓解模型性能退化问题。实验结果显示,相较于非自适应全局GMR模型、时间局部学习集成GMR模型、空间局部学习集成GMR模型,所提方法在金霉素发酵过程中的预测精度分别提升了70.3%,14.9%,27.8%;在脱丁烷塔过程中,分别提升了31.9%,21.2%,19.3%。     

Reducing vulnerability to soft errors in sub-100 nm content addressable memory circuits

We first study the impacts of soft errors on various types of CAM for different feature sizes. After presenting a soft error immune CAM cell, SSB-RCAM, we propose two kinds of reliable CAM, DCF-RCAM and DCK-RCAM.In addition, we present an ignore mechanism to protect dual cell redundancy CAMs against soft errors. Experimental results indicate that the 11T-NOR CAM cell has an advantage in soft error immunity. Based on 11T-NOR, the proposed reliable CAMs reduce the SER by about 81% on average with acceptable overheads. The SER of dual cell redundancy CAMs can also be decreased using the ignore mechanism in specific applications.     

Soft error generation analysis in combinational logic circuits

Reliability is expected to become a big concern in future deep sub-micron integrated circuits design.Soft error rate(SER) of combinational logic is considered to be a great reliability problem.Previous SER analysis and models indicated that glitch width has a great impact on electrical masking and latch window masking effects,but they failed to achieve enough insights.In this paper,an analytical glitch generation model is proposed.This model shows that after an inflexion point the collected charge has an...     

泉州某软土基坑侧壁失稳分析及设计改进

泉州某软土基坑在开挖至底板设计标高时,发生了滑塌事故。滑坡长度达72m,基坑侧壁发生严重的侧向位移,滑裂面处出现了较大的裂缝。本文针对该基坑滑塌面的特征,对滑塌处的支护结构进行了分析,阐明了基坑失稳破坏的原因,并根据再次勘察后的土体强度对滑塌处改进了支护设计,并对加固治理方案进行了分析评价。本文的研究结果对于软土地区类似的基坑工程有一定的参考价值。