深基坑支护结构和施工新技术

简要介绍了我国基坑工程发展概况,重点介绍了复合土钉墙、双排桩、型钢水泥土搅拌墙等新型支护结构以及几种施工新设备、新工艺。分析了地下结构逆作法和利用"时空效应"开挖技术的工程应用。     

Pediatric Brain Tumors: Signatures from the Intact Proteome

The present investigation aimed to explore the intact proteome of tissues of pediatric brain tumors of different WHO grades and localizations, including medulloblastoma, pilocytic astrocytoma, and glioblastoma, in comparison with the available data on ependymoma, to contribute to the understanding of the molecular mechanisms underlying the onset and progression of these pathologies. Tissues have been homogenized in acidic water–acetonitrile solutions containing proteases inhibitors and analyzed by LC–high resolution MS for proteomic characterization and label-free relative quantitation. Tandem MS spectra have been analyzed by either manual inspection or software elaboration, followed by experimental/theoretical MS fragmentation data comparison by bioinformatic tools. Statistically significant differences in protein/peptide levels between the different tumor histotypes have been evaluated by ANOVA test and Tukey’s post-hoc test, considering a p-value > 0.05 as significant. Together with intact protein and peptide chains, in the range of molecular mass of 1.3–22.8 kDa, several naturally occurring fragments from major proteins, peptides, and proteoforms have been also identified, some exhibiting proper biological activities. Protein and peptide sequencing allowed for the identification of different post-translational modifications, with acetylations, oxidations, citrullinations, deamidations, and C-terminal truncations being the most frequently characterized. C-terminal truncations, lacking from two to four amino acid residues, particularly characterizing the β-thymosin peptides and ubiquitin, showed a different modulation in the diverse tumors studied. With respect to the other tumors, medulloblastoma, the most frequent malignant brain tumor of the pediatric age, was characterized by higher levels of thymosin β4 and β10 peptides, the latter and its des-IS form particularly marking this histotype. The distribution pattern of the C-terminal truncated forms was also different in glioblastoma, particularly underlying gender differences, according to the definition of male and female glioblastoma as biologically distinct diseases. Glioblastoma was also distinguished for the peculiar identification of the truncated form of the α-hemoglobin chain, lacking the C-terminal arginine, and exhibiting oxygen-binding and vasoconstrictive properties different from the intact form. The proteomic characterization of the undigested proteome, following the top-down approach, was challenging to originally investigate the post-translational events that differently characterize pediatric brain tumors. This study provides a contribution to elucidate the molecular profiles of the solid tumors most frequently affecting the pediatric age, and which are characterized by different grades of aggressiveness and localization.     

自顶向下优化神经网络的方法

介绍了一种自动优化神经网络的新启迪方法.这种启迪方法综合采用了快速自顶向下优化神经网络结构算法、动态优化学习参数算法和快速交叉校验算法.首先,快速自顶向下优化神经网络结构算法自动地优化神经网络结构;其次,动态优化学习参数算法动态地调整学习参数和选取优化的学习参数;随后,快速交叉校验算法的引入能有效地防止过度适应问题.实验结果显示,这种启迪方法与其它算法相比,具有更强的归纳性能、优化的网络结构和更快的学习速度.     

产品自顶向下设计的研究现状及发展方向

给出了自顶向下设计所涉及的关键技术、国内外研究现状、存在的问题及发展方向。首先介绍了自顶向下的设计过程；然后介绍关键技术及研究现状，包括产品装配模型的表达方式、装配模型的建模方法、装配模型的优化分析方法和装配顺序规划等；最后给出各关键技术的发展方向。     

纳米电子器件及其集成

对基于Top-Down加工技术的纳米电子器件如：单电子器件、共振器件、分子电子器件等的研究现状、面临的主要挑战等进行了讨论. 采用CMOS兼容的工艺成功地研制出单电子器件，观察到明显的库仑阻塞效应；在半绝缘GaAs衬底上制作了AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs双势垒共振隧穿二极管,采用环型集电极和薄势垒结构研制的共振隧穿器件，在室温下测得其峰谷电流比高达13.98，峰电流密度大于89kA/cm2；概述了交叉阵列的分子存储器的研究进展.     

基于变形控制的逆作法超大深基坑的数值模拟

基于变形控制和环境安全的要求，对天津某项目超大深基坑进行了施工过程的数值模拟。考虑地下室施工采用楼板作为内支撑的楼板逆作工法以及基坑围护结构应力应变的复杂性，采用通用有限元程序ANSYS建立了三维空间模型进行计算。试算得到安全可靠的深基坑设计方案，并对方案控制工况施工状态基坑围护结构以及水平楼板的内力和变形进行了分析，同时还对楼面板作用进行了分析。     

Object recognition using a bio-inspired neuron model with bottom-up and top-down pathways

In this paper, a new artificial neural network model is proposed for visual object recognition, in which the bottom-up, sensory-driven pathway and top-down, expectation-driven pathway are fused in information processing and their corresponding weights are learned based on the fused neuron activities. During the supervised learning process, the target labels are applied to update the bottom-up synaptic weights of the neural network. Meanwhile, the hypotheses generated by the bottom-up pathway produce expectations on sensory inputs through the top-down pathway. The expectations are constrained by the real data from the sensory inputs, which can be used to update the top-down synaptic weights accordingly. To further improve the visual object recognition performance, the multi-scale histograms of oriented gradients (MS-HOG) method is proposed to extract local features of visual objects from images. Extensive experiments on different image datasets demonstrate the efficiency and robustness of the proposed neural network model with features extracted using the MS-HOG method on visual object recognition compared with other state-of-the-art methods.     

苏州火车站改造工程盖挖逆作法施工技术

介绍了苏州火车站改造工程在低渗透性、饱和、软流塑的软弱地层中采用盖挖逆作法修筑地铁车站的施工技术，指出在地铁车站施工中，盖挖逆作法对工程环境影响较小，工期短，综合技术经济指标较为理想，可推广应用。     

德基广场逆作柱及地下连续墙施工质量控制

本文主要介绍了德基广场逆作法施工中逆作柱及地下连续墙的质量控制难点,通过计算机及人工测量的方法较好控制了基坑垂直度、平整度。通过合理的施工工序及人员配置,保证了混凝土浇筑质量。实践证明,施工措施有效、控制得力,保证了工程支架吊装位置准确,垂直度偏差小,墙幅间无渗漏。     

上海世博500kV地下变电站圆形深基坑逆作法变形与受力特性实测分析

上海世博500kV地下变电站是直径为130m的深埋圆筒形全地下结构,采用全逆作法施工。针对基坑工程特点,基坑开挖期间建立了全过程、全方位的监测系统,完整地记录了施工过程中围护结构的变形与内力和周边环境的变形。监测数据表明：围护结构的侧向变形明显小于相同开挖深度的其它基坑工程,地下连续墙呈现以水平受力为主的圆形结构特点,体现了圆形基坑环向受力的特点和利于变形控制的优点。该工程各项监测数据均在允许值范围之内,验证了相关设计参数的合理性和理论研究的正确性,为软土地区类似深基坑工程的设计和施工提供参考和借鉴。