甲醇装置原料路线结构调整的工艺方案

山西焦化股份有限公司拟实施35万t/a甲醇装置原料路线结构调整的技术改造。对比了多种气化工艺方案及配套的净化工艺方案;提出了水冷壁气化炉及加压湿法脱硫串PSA脱碳的技改方案。结果表明:采用该技改方案,可降低甲醇生产成本979万元/a,技改项目的投资回收期为7年。

基于模式匹配的网格扫描法在高铁线下结构检测中的应用

高铁是连接地区交通的纽带,我国计划2030年将建成近4万km的高速铁路,形成八横八纵铁路网;但是高速铁路线下结构在长期的运营中会产生如混凝土裂缝、结构层脱空、砂浆层离隙等病害。高速铁路线下结构病害检测要求效率高、精度高、设备集成化程度高;针对高铁线下结构的典型病害CA砂浆层脱空及离隙,提出了基于模式匹配法的网格化扫描检测方法,该方法基于线下结构标准设计,考虑砂浆层离隙的空间分布特征,建立三维有限元模型;通过数值模拟,模拟不同病害下网格化扫描法接收的弹性波响应,完成病害特征匹配库;通过多轮匹配、权重值矩阵和阈值函数,设计了模式匹配算法,对匹配的结构损伤识别要素进行敏感性分析,通过合理设计网格尺寸实现病害平面分布20 cm内的精确评价。设计了网格化检波器阵列,成功应用到沪杭高铁虹桥站线下结构检测中,完成线下结构快速、实时、定量化的病害检测。

仿真体系结构发展现状与趋势研究

随着信息技术的飞速发展,特别是cyber空间、cyber对抗等新概念、新技术的提出,要求仿真体系结构能够适应网络化、通用化、服务化、集成化的发展趋势,具有高可重用性、可扩展性、可组合性与互操作性,这对目前我军广泛采用的仿真体系结构带来了严峻挑战。美军是目前主流仿真体系结构相关标准的制定者,代表了世界的先进水平,因此,对美军目前广泛采用的多个仿真体系结构进行了深入调研,着重分析了各个体系结构的技术特点、存在的问题,研究了美军用于指导未来仿真体系结构发展的路线图。在此基础上,提出了我军新一代仿真体系结构发展的建议。

工程机械企业技术路线图的研究及应用——山河智能技术管理创新实践

技术路线图作为一种实施技术管理的有效工具,是用于科研和产品战略性规划的方法。本文简要介绍技术路线图的定义,技术路线图的基本结构,以及技术路线图对企业技术管理的应用分析;同时对山河智能装备股份有限公司(以下称"山河智能")技术路线图的实施情况进行了写实性的介绍,借此对工程机械企业如何实施技术路线图提出几点建议。

步行城市设计研究的三个方向

文章梳理了步行城市的相关政策与文献之间的对应关系,指出步行城市与车行城市有着截然不同的形态模型,并且必须重塑城市的步行网络。针对已有步行网络的研究方法,文章指出仅仅为了制定规范与标准而进行研究是远远不够的,更需要进行步行城市设计的研究。由此,文章进一步分析了步行行为的八个典型特征,并对当下城市提出了七点质疑。最后,文章概述性地介绍了嗯工作室的三个步行城市设计研究方向:用于量化分析步行网络效率与选择的EC模型、用于设计研究的路线结构以及引入艺术手段的城市图景。文章提出建设步行城市应有鲜明的立场、执着的理性、精深的技艺、丰富的情感与天马行空的想象力。

三江并流带旅游地质景观

强烈新构造运动造就宏伟、稀罕、绚丽的三江并流带地质奇观,蕴育丰富、珍稀的旅游地质资源。本文就三江并流带旅游地质资源类型、景观单元及其等级、景观系列、景观结构、展布特征及区划、特色进行剖析,推荐观赏三江并流旅游地质景观的特色景观组合及精品线路。

配电系统的运维管理分析

阐述配电运维管理中的问题和改进措施,包括合理设计配电网路线结构、完善运维管理制度,从而保障配电网呈现持续良好的运作状态。

Longitudinal forces of continuously welded track on high-speed railway cable-stayed bridge considering impact of adjacent bridges

A proven beam-track contact model was used to analyze the track-structure interaction of CWR (continuously welded track) on bridge. Considering the impact of adjacent bridges, the tower-cable-track-beam-pier-pile finite element model of the cable-stayed bridge was established. Taking a bridge group including 40-32m simply-supported beam and (32+80+112)m single-tower cable-stayed bridge and 17-32m simply-supported beam on the Kunming-Shanghai high-speed railway as an example, the characteristics of CWR longitudinal force on the cable-stayed bridge were studied. It is shown that adjacent bridges must be considered in the calculation of the track expansion force and bending force on cable-stayed bridge. When the span amount of adjacent bridges is too numerous, it can be simplified as six spans; the fixed bearing of adjacent simply-supported beams should be placed on the side near the cable-stayed bridge; the track expansion device should be set at the bridge tower to reduce the track force near the bridge abutment.

Mechanics model of additional longitudinal force transmission between bridges and continuously welded rails with small resistance fasteners

A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement (among) the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges.

Effect of processing routes on microstructure and mechanical properties of 2014 Al alloy processed by equal channel angular pressing

Al-Cu alloy was deformed through equal channel angular pressing(ECAP) by routes A,Ba,Bc and C up to 5 passes.ECAP was done using a 90° die for three different conditions,namely 1) as received,2) solutionised at 768 K for 1 h and 3) solutionised at 768 K for 1 h + aged at 468 K for 5 h.The microstructure,microhardness and tensile strength were studied for all the three conditions and four routes.Significant improvement in hardness(HV 184 after five passes) and strength(602 MPa after three passes) was observed in solutionised and aged 2014 Al alloy deformed through route Bc.Microstructure evolution was reasonably equiaxed in route Bc with aspect ratio of 1.6.Solutionised and aged 2014 Al alloy deformed through route Bc was identified to have better microstructure and mechanical property than the other processing routes and conditions.

Methods and Prospects of Road and Linear Structure Automatic Extraction from Remote Sensing Images

Automatic extraction of road and linear structure from remote sensing images is a very important problem. This paper analyses several existing methods of the automatic road and linear structure extraction by using some multi-spectral remote sensing images acquired from different spatial resolutions, districts and road characteristics. Their advantages and disadvantages have been generalized.

Study of Structural, Electrical and Magnetic Properties of Manganese Doped Cobalt Ferrite Nanoparticles with Non-stoichiometric Composition

The nanoparticles of Co1＋xMnxFe2-xO4 （0≤x ≤ 0.5） ferrite system are synthesized by solid-state reaction route using planetary ball milling technique to investigate structural, electrical and magnetic properties. The X-ray diffraction patterns confirm the inverse spinel structure with residual oxide phases. Three distinct regions of frequency response on dielectric constant are observed Co1.2sMn0.5Fe1.75O4 as determined by the Wayne Kerr Impedance Analyzer. The first two regions of frequency response 1.13-4.5 MHz and 4.5-6.5 MHz exhibit the normal behavior but the last region 6.5-10.5 MHz indicates its anomalous behavior due to concurrent contribution of O^2-, Fe^3＋, Co^2＋ and Mn^3＋ ions in the relaxation process for sintering effects （sintered at 700℃）. This anomalous behavior is found to be pronounced and significant for the sample of composition Co1.25Mn0.25Fe1.75O4, which may be suitable to be used in the frequency band filter over wide range of frequencies. The single peak of imaginary part of dielectric constant （ε＂） indicates that the conduction process in this sample is due to the grain boundary resistance. The pronounced increase of capacitance （C） as observed from 100 ℃ to 125 ~C in temperature dependent measurement （30-125℃） is expected to eause from the change of polarization across the grain boundary due to redistribution of ions by the thermal agitation. The variation of resistance （R） with temperature （30-125 ℃） is found to exhibit semieonducting behavior that resulted from the p-type carriers （Co^2＋/Co^3＋）. A significant increase of Z from 105 ℃ with the increase of temperature indicates the signature of phase transition from ferrimagnetic-to-ferromagnetic, which may be ascribed to the increase of Co content. The appearance of the single semicircular arc in the Cole-Cole plot may be attributed to the contribution of grain boundary resistance and correspond to the parallel equivalent circuit of resistor-capacitor （R-C） combination with single relaxation time. Saturation magnetization of Co1.25Mn0.25Fe1.75O4 and Co1.375Mn0.375Fe1.625O4 is found to be greater than the literature value （61.5 emu/g） of un-doped cobalt ferrite in the measurement of their initial magnetization using Lakeshore vibrating sample magnetometer. The negative real part of AC permeability of Co1.5Mn0.5Fe1.5O4 signifies the diamagnetic behavior in the frequency range 0.13-25.2 MHz and expected to cause from the formation of magnetic dipoles opposite to the applied field due to Mn^2＋ in the B site. The samples are expected to be suitable for dielectric heating and high frequency applications.

Optimized Multicast Routing Algorithm Based on Tree Structure in MANETs

Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.

Cluster-Based Content Download and Forwarding Scheme for Highway VANETs

The recent advances in wireless communication technology enable high-speed vehicles to download data from roadside units(RSUs). However, the data download volume of individual vehicle is rather restricted due to high mobility and limited transmission range of vehicles, bringing users poor performance. To address this issue, we exploit the combination of both clustering and carry-and-forward schemes in this paper. Our scheme coordinates the cooperation of multiple infrastructures, cluster formation in the same direction and data forwarding of reverse vehicles to facilitate the target vehicle to download large-size content in dark areas. The process of data dissemination and achievable data download volume are then derived and analyzed theoretically. Finally, we conduct extensive simulations to verify the performance of the proposed scheme. Results show significant benefits of the proposed scheme in terms of increasing data download volume and throughput.

尖晶石LiMn2O4的合成工艺与评价

本文采用不同的起始原料,分别用Pechini法、熔融盐浸渍法和沉淀转化法制备用于锂离子电池正极材料的尖晶石锰酸锂LiMnO4,结合化学分析和X射线衍射分析对产物进行表征.实验结果表明,三种工艺均能制备单相尖晶石,晶格参数与纯LiMn2O4一致:Pechini法制得的产物晶粒度和颗粒尺寸最小,分别为～17nm和～1.5μm.由于三种工艺分别制备了高活性的前驱物,反应组分混合均匀,使固相合成反应能在800℃下6～8小时完成.同时,热处理制度的研究表明,提高煅烧温度可能引起锰的还原,而延长煅烧时间会促进锰的氧化,有助于获得不缺氧的尖晶石.在实验的三种工艺路线中,沉淀转化法是最有希望工业化的.

Theory and application of infrared surveying gas gushing technology in coal-rock roadway

Geological structure and gas expansion when gas pressure was released can affect the distribution of infrared radiation energy or temperature at coal rock surface. From this, the foundation of roadway infrared surveying technical was formed. According to the thermodynamic principle of ideal gas and the law of energy conservation, the relation was established between gas gushing amount from coal rock and air temperature to fall in roadway. At the same time, this paper has analyzed coal rock density change that geological structure aroused and the change exerted influences on infrared radiation power at surface, as well as, has analyzed the infrared radiation feature of gas gushing at geological structure district. Application results show that infrared survey technology can be used to analyze and forecast the change of coal rock gas gushing effectively, and to guide the enforcement of the roadway gas project of prevention and handling economically.

Clustering Approaches for Overhead Reduction over Coordinated Multiple Points Network-MIMO Downlink Systems

Owing to the potential for intercell cochannel interference mitigation and significant spectral efficiency improvement, coordinating transmission techniques by multiple radio access points have recently attracted a lot of attention. In this paper, the system structure and mathematical signal model based on clustered structure are presented for multipoint coordinating downlink transmission, the clustered supercell configurations with static/dynamic approaches are discussed, and then optimal precod- ing design is provided for an accepted level of scheduling complexity and reduced signaling over- head. Some simulation results are given to evaluate the performance of different cell-clustering approaches, and to show that a clustered supercell size of 7 is a reasonable choice for clustered coordination with the given transmit power and the reduced feedback.

Self-assembly and chemical processing of block copolymers:A roadmap towards a diverse array of block copolymer nanostructures

Block copolymers can yield a diverse array of nanostructures.Their assembly structures are influenced by their inherent structures,and the wide variety of structures that can be prepared especially becomes apparent when one considers the number of routes available to prepare block copolymer assemblies.Some examples include self-assembly,directed assembly,coupling,as well as hierarchical assembly,which can yield assemblies having even higher structural order.These assembly routes can also be complemented by processing techniques such as selective crosslinking and etching,the former technique leading to permanent structures,the latter towards sculpted and the combination of the two towards permanent sculpted structures.The combination of these pathways provides extremely versatile routes towards an exciting variety of architectures.This review will attempt to highlight destinations reached by LIU Guojun and coworkers following these pathways.

Elastic-plastic seismic response of CRTS II slab ballastless track system on high-speed railway bridges

China railways track structure II (CRTS II) slab ballastless track on bridge is one kind of track structures unique to China. Its main bearing component of longitudinal force is the continuous base plate rather than rail. And the track-bridge interaction is weakened by the sliding layer installed between base plate and bridge deck. In order to study the dynamic response of CRTS II slab ballastless track on bridge under seismic action, a 3D nonlinear dynamic model for simply-supported bridges and CRTS II track was established, which considered structures such as steel rail, fasteners, track plate, mortar layer, base plate, sliding layer, bridge, consolidation, anchors, stoppers, etc. Then its force and deformation features under different intensities of seismic excitation were studied. As revealed, the seismic response of the system increases with the increase of seismic intensity. The peak stresses of rail, track plate and base plate all occur at the abutment or anchors. Both track plate and base plate are about to crack. Besides, the rapid relative displacement between base plate and bridge deck due to the small friction coefficient of sliding layer is beneficial to improve the seismic performance of the system. During the earthquake, a large vertical displacement appears in base plate which leads to frequent collisions between stoppers and base plate, as a result, stoppers may be damaged.

Circuit model based design and analysis for a four-structure-switchable wireless power transfer system

The four-coil wireless power transfer(WPT)technology can effectively improve the transfer efficiency.The high efficiency,however,cannot be obtained along the whole transfer distance due to the phenomenon of frequency splitting in the over coupled region.Aiming at this limitation,this paper presents a switchable WPT system to improve the overall efficiency by changing the number of working coils.The switching conditions for the designed system are determined based on the analysis of the transfer efficiencies of four structures,which is deduced through modeling the equivalent circuits.The simulation results well comply with the experimental results and both of them indicate that the switchable system can greatly improve the overall transfer efficiency along the whole transfer distance.The overall efficiency of the experimental system can reach above 70%at9.97 MHz without additional complexity,which is higher than any single structure system.