影响光纤宽带网络建设投资和综合造价的因素分析

影响光纤宽带网络工程建设投资和综合造价的因素众多,不可能把全国或全省的工程造价控制在同一个水平上。目前,新建区域基本以光纤到户（FTTH）接入方式为主,现有区域的改造主要以FTTH和光纤到楼（FTTB）接入方式为主,并辅以其他接入方式。接入方式不同则造价不同,即便是同一接入方式,不同场景下的各地综合造价也有较大差别,从而直接影响到了建设投资。以FTTH为例,从建设场景、建设方式、覆盖方式、分光方式、覆盖深度、建设标准、地区性差异、操作方式、设备集采等方面,全面分析了影响光纤宽带网络建设的投资和综合造价因素。     

大坝混凝土强度参数的统计分析

抗拉强度和抗压强度是常用的两种混凝土强度指标。抗拉强度可以采用轴向拉伸试验、弯曲试验和劈裂抗拉强度试验测定,抗压强度由立方体抗压强度试验测定。大坝混凝土的材料试验常采用全级配大试件和湿筛小试件两种形式。不同尺寸试件、不同类型试验的混凝土强度指标存在一定的统计关系。本文结合实际混凝土大坝工程,对全级配混凝土及湿筛混凝土的各种静、动强度试验结果进行总结,研究混凝土强度的率效应、尺寸效应,分析各强度指标之间的定量关系,并与国内、外规范及相关成果进行比较,为实际工程提供可参考的依据。     

基于DSP和VXI-11协议的LXI仪器控制与实现

为实现嵌入式系统对LXI仪器的远程控制,采用DSP芯片扩展DP83848C以太网接口芯片的硬件方案和基于简化TCP/IP协议及RPC协议支持的软件方案,在分析TCP连接过程、RPC调用流程和VXI-11协议工作过程的基础上,设计实现了支持VXI-11协议的嵌入式硬件平台和控制软件;以RS SMB100A微波信号源为被控对象的实验测试及数据分析结果表明,文中的硬件平台和控制软件可以根据协议工作时序正确发送控制数据包,LXI仪器可以正确响应嵌入式端的远程控制命令;文章提出的基于DSP和VXI-11协议的LXI仪器控制方案即可以用于实现分布式、低成本、灵活性较高的自动测试系统,也可以用于LXI仪器控制的桥接方案设计。     

A Highly Reversible Long‐Life Li–CO2 Battery with a RuP2‐Based Catalytic Cathode

Rechargeable Li–CO₂ batteries have attracted worldwide attention due to the capability of CO₂ capture and superhigh energy density. However, they still suffer from poor cycling performance and huge overpotential. Thus, it is essential to explore highly efficient catalysts to improve the electrochemical performance of Li–CO₂ batteries. Here, phytic acid (PA)‐cross‐linked ruthenium complexes and melamine are used as precursors to design and synthesize RuP₂ nanoparticles highly dispersed on N, P dual‐doped carbon films (RuP₂‐NPCFs), and the obtained RuP₂‐NPCF is further applied as the catalytic cathode for Li–CO₂ batteries. RuP₂ nanoparticles that are uniformly deposited on the surface of NPCF show enhanced catalytic activity to decompose Li₂CO₃ at low charge overpotential. In addition, the NPCF its with porous structure in RuP₂‐NPCF provides superior electrical conductivity, high electrochemical stability, and enough ion/electron and space for the reversible reaction in Li–CO₂ batteries. Hence, the RuP₂‐NPCF cathode delivers a superior reversible discharge capacity of 11951 mAh g^?1, and achieves excellent cyclability for more than 200 cycles with low overpotentials (<1.3 V) at the fixed capacity of 1000 mAh g^?1. This work paves a new way to design more effective catalysts for Li–CO₂ batteries.     

Plastic Microfluidic Systems for High-Throughput Genomic Analysis and Drug Screening

Genomic analysis and drug discovery depend increasingly on rapid, accurate analysis of large sets of sample and extensive compound collections at relatively low cost. By capitalizing on advances in microfabrication, genomics, combinatorial chemistry, and assay technologies, new analytical systems are expected to provide order-of-magnitude increases in analysis throughput along with comparable decreases in per-sample analysis costs. ACLARA's single-use, plastic LabCard™ systems, which transport fluids between reservoirs and through interconnected microchannels using electrokinetic mechanisms, are intended to address these analytical needs. These devices take advantage of recent developments in microfluidic and microfabrication technologies to permit their application to DNA sequencing; genotyping and DNA fragment analysis, as well as pharmaceutical candidate screening, and preparing biological samples for analysis. In a parallel effort, ACLARA has developed a new class of reporter molecules that are particularly well suited to capillary electrophoretic analysis. These electrophoretic mobility tags, called eTag™ reporters, can be used to uniquely label multiplexed sets of oligonucleotide recognition probes or proteins, thereby permitting traditionally homogeneous biochemical reporter assays to be multiplexed for CE analysis. Biochemical multiplexing is key to achieving new thresholds in analytical throughput while maintaining economically viable formats in many application areas. ACLARA's microfluidic, lab-on-a-chip concept promises to revolutionize chemical analysis, similar to the way miniaturization revolutionized computing, making tools continually smaller, more integrated, less expensive, and higher performing.     

Super Strengthening Nano-Polycrystalline Diamond through Grain Boundary Thinning

Introducing nanostructures into diamonds is quite appealing for the synthesis of superhard materials with superior properties. However, as the grain size decreases to nanoscale, grain boundary effects become crucial yet complicated in the nanopolycrystalline diamond (NPD), making it challenging to tailor nanostructures. Here, atomistic simulations are combined with experiment to demonstrate a strengthening strategy for the sintered NPD by introducing thin amorphous grain boundary (AGB). The additive of small percentage of fullerene into precursors during sintering can significantly reduce crushed amorphous-like nanodomains in diamond nanocrystals, leading to the formation of thin AGB. Such sintered NPD exhibits a significant hardness and fracture toughness enhancement, exceeding that of single crystal diamonds. These atomistic simulations show that upon straining the plastic deformation, crack initiation and propagation in NPD is AGB thickness dependent, and thin AGB can reduce crack nucleation and block crack propagation, well explaining the experimental observations. This study indicates that grain boundary modulation provides a promising approach for rational designs of high-performance superhard materials with desired high strength.     

基于轻量级深度神经网络的环境声音识别

针对传统卷积神经网络（CNN）模型存在大量冗余参数的问题，提出了两个基于SqueezeNet核心结构Fire模块的轻量级网络模型Fnet1和Fnet2。之后结合移动端分布式数据采集和处理的特点，在Fnet2模型基础上，依据Dempster-Shafer（D-S）证据理论将Fnet2与深度神经网络（DNN）融合，提出新的网络模型FnetDNN。首先，建立一个具有四层卷积层的神经网络Cent作为基准，以梅尔倒谱系数（MFCC）作为特征输入来对比分析Fnet1、Fnet2和Cent的网络结构特点、计算量、卷积核参数数量及识别准确率，结论是Fnet1仅使用Cnet参数数量的10.3%就可达到86.7%的分类准确率；然后，将MFCC与全局特征向量输入到FnetDNN模型中，使得该模型的识别准确率提高到了94.4%。实验结果表明，Fnet网络模型不仅可以压缩冗余参数，还可以与其他网络相融合，具备模型扩展能力。     

基于支撑向量机的支票手写体数字识别系统

该文提出了一种基于支撑向量机的支票手写体数字识别系统。支撑向量机方法,由于建立在结构风险最小化的基础上,而不仅仅使经验风险达到最小,从而突破了传统模式识别方法的局限,使得基于支撑向量机的分类器具有较好的推广能力。文中重点阐述了支撑向量机的基本原理和集成在该系统中的重要的处理模块,实验结果表明该系统具有较高的识别率和较强的实用性。     

稀土固体超强酸SO42-/TiO2/Ce(Ⅳ)催化合成邻苯二甲酸二丁酯

以苯酐和正丁醇为原料,稀土固体超强酸SO42-/TiO2/Ce(Ⅳ)为催化剂,合成了邻苯二甲酸二丁酯。考察了影响反应的因素。结果表明:当醇∶苯酐(摩尔比)=2.4∶1,催化剂用量占总反应物的4%,反应温度为190℃,反应时间5h时,酯收率可达95%以上。     

交联剂对聚氨酯乳液性能的影响

合成了以水合联氨、乙二胺、二乙烯三胺、三乙烯四胺为交联剂的聚氨酯水乳液。探讨了不同交联剂及同种交联剂不同用量对聚氨酯水乳液粘度、储存稳定性、胶膜力学性能的影响及相应乳液在纸涂层中的作用。结果表明:交联剂过量不利于乳液的储存稳定性;胶膜的扯断强度按水合联氨、乙二胺、二乙烯三胺、三乙烯四胺的顺序依次增强:以二乙烯三胺为交联剂的乳液用于纸涂层中显示的综合性能最好。