振动法水泥稳定砾石的力学疲劳特性与强度标准

为确保振动法水泥稳定砾石(VTM-CSG)基层在交通荷载反复作用下不出现疲劳破坏,研究了VTM-CSG的疲劳特性与不同龄期的力学强度(无侧限抗压强度、劈裂强度与抗压回弹模量);基于路面荷载响应、VTM-CSG的力学与疲劳特性,结合Miner疲劳累积损伤理论,提出了抗疲劳开裂的VTM-CSG强度标准.结果表明:VTM-CSG力学强度随水泥剂量的增加呈线性增加、随养生龄期的延长呈非线性增长,采用骨架密实级配可提高VTM-CSG的力学强度;所建立的VTMCSG强度增长方程可较为精确地表征其强度增长特性;当试验条件受限时,可利用所建立的力学指标间的关系模型来预估其他力学强度.通过回归分析建立的VTM-CSG疲劳方程表明,在高应力水平下骨架密实级配VTM-CSG的疲劳性能优于悬浮密实级配VTM-CSG;提出了控制疲劳开裂的VTM-CSG的7d无侧限抗压强度标准与7d劈裂强度标准,该标准与路面结构、VTM-CSG的材料属性以及使用寿命相关联,实现了结构与材料一体化控制VTM-CSG基层开裂的目的.     

基于振动法的抗疲劳断裂水泥稳定碎石强度标准研究

强度是水泥稳定碎石材料设计与施工质量控制重要指标。当集料类型、矿料级配和成型方式一定情况下,水泥稳定碎石强度取决于水泥剂量。强度标准越高,则水泥剂量越大,水泥稳定碎石抗荷载破坏能力越强,但抗收缩开裂能力越差;反之亦然。为此,以水泥稳定碎石基层施工期和运营期在荷载作用下不发生疲劳破坏所需材料最小强度为准则,研究了水泥稳定碎石力学强度特性、疲劳特性及施工期与运营期水泥稳定碎石基层荷载响应,提出抗疲劳断裂的水泥稳定碎石强度标准。结果表明：为防止施工车辆荷载作用下基层发生极限断裂破坏,水泥稳定石灰岩碎石基层必须养护7d后,且其劈裂强度达到0.68MPa以上,方可进行下结构层施工;为防止设计年限内基层在施工车辆和运营车辆反复作用下产生疲劳断裂,水泥稳定石灰岩碎石7d劈裂强度不小于0.70MPa。为了便于应用,结合抗压强度和劈裂强度之间关系,提出水泥稳定石灰岩碎石7d抗压强度不小于7.0MPa。     

Simulation of wind turbine wake interaction using the vorticity transport model

The aerodynamic interactions that can occur within a wind farm can result in the constituent turbines generating a lower power output than would be possible if each of the turbines were operated in isolation. Tightening of the constraints on the siting of wind farms is likely to increase the scale of the problem in the future. The aerodynamic performance of turbine rotors and the mechanisms that couple the fluid dynamics of multiple rotors can be most readily understood by simplifying the problem and considering the interaction between only two rotors. The aerodynamic interaction between two rotors in both co‐axial and offset configurations has been simulated using the Vorticity Transport Model. The aerodynamic interaction is a function of the tip speed ratio, and both the streamwise and crosswind separation between the rotors. The simulations show that the momentum deficit at a turbine operating within the wake developed by the rotor of a second turbine is governed by the development of instabilities within the wake of the upwind rotor, and the ensuing structure of the wake as it impinges on the downwind rotor. If the wind farm configuration or wind conditions are such that a turbine rotor is subject to partial impingement by the wake produced by an upstream turbine, then significant unsteadiness in the aerodynamic loading on the rotor blades of the downwind turbine can result, and this unsteadiness can have considerable implications for the fatigue life of the blade structure and rotor hub. Copyright © 2009 John Wiley & Sons, Ltd.     

试析远程视频柜员机助力商业银行金融服务创新

随着利率市场化以及互联网金融对传统金融业的冲击,优化传统银行网点服务模式,为客户提供个性化更高效的金融服务成为银行业急需解决的问题。VTM远程视频柜员机作为银行自助设备的集大成者,具有为客户提供对公对私、国际国内、金融理财等全方位金融服务能力,成为银行业应对新形势下金融服务创新的有效解决方案。     

基于熵平衡的全景视频编码

高效的全景视频压缩对沉浸式、低延时的视觉体验十分重要。服务器端的全景视频通过投影到2D平面,经过编码、传输到客户端后,反投影到球面供用户观看,而全景视频投影过程中会在两极产生拉伸形变,由于过采样而产生像素冗余,破坏原有的信息熵分布。针对这一问题,提出一种改进的熵平衡算法,根据全景视频投影前后对应编码单元的熵不变原则,采用码率控制的R-λ模型根据投影面积变化比率来重新分配目标比特,以达到熵平衡,进而调整编码参数优化编码。实验结果表明,该算法相较于基准VTM14.0能达到1.87%的码率节省,编码时间下降10.07%,说明该算法在全景视频编码中能实现更高的压缩率和更短的编码时间。     

Exeperience of operating a new generation of steel-pouring systems and refractories for them

The achievements of NPP Vulkan-TM in the production of basic forms of production (slide gates, vibration-molded refractories, ceramics, systems for blowing metal with argon, etc.) are analyzed. Specific attention is devoted to the development and introduction of a new slide gate VTM-50V, the results of testing the life of plates of Russian and overseas production within a new generation of slide gates, and also vibration-cast high-alumina refractories within a set of refractories for slide gates of the VTM series. Translated from Novye Ogneupory, No. 1, pp. 15–17, January 2009.     

VTM柜员机造型设计的感性工学研究

目的 将感性工学纳入产品设计,试图形成一套规范化的设计流程,解决VTM柜员机现存的问题,归纳总结VTM产品设计要点,为其他设计者提供借鉴思路。方法 本文以VTM柜员机造型设计为出发点,结合感性工学的研究方法,辅以熟知的人机工程学,对感性工学在产品造型设计中运用的可能性进行讨论。结论 将感性工学纳入产品设计,形成规范化流程,并梳理出VTM产品设计的设计要点。     

场景可视化在VTM系统体验设计中的应用

目的为了把满足"用户真正需求"的用户体验切实可行地落实到产品操作以及服务流程中去,寻求银行环境、VTM(可视柜台)机器、用户体验之间的关系,以此总结出VTM系统体验设计的原则。方法通过实地考察和角色扮演结合场景可视化技术,处理生成在同一新型银行网点下不同用户需求的历程图。结论场景可视化能够充分反映用户的真实需求,并且能够将网点用户活动与网点环境相结合,从而提出更加适宜的VTM用户体验设计原则,最终为用户打造一个优化、高效、互联、整合、友善、安全的VTM系统,为用户提供更为友好的业务办理体验。     

Preparation and characterization of electromagnetic wave absorbing material from polymetallic vanadium titano-magnetite (VTM): Oriented phase transformation underlying formation mechanism

Polymetallic vanadium titano-magnetite (VTM) is recognized as one of the most refractory mineral resources because of its multiple-element composite symbiosis feature. Conventional carbothermic reduction and smelting separation treatment are characterized by high energy consumption and large greenhouse gas emissions. Considering the material attribute, an alternative and clean utilization of refractory VTM via the pyrometallurgically oriented phase transformation in air atmosphere to prepare the composite electromagnetic wave absorbing material was proposed for the first time in this work. The theoretical foundation of the oriented composite material design, phase transformation, microstructure and interfacial element migration, magnetism, electromagnetic properties, and wave absorbing properties were investigated via thermodynamic calculations, XRD, XPS, optical microscope, SEM?EDS, VSM, and VNA analyses. Theoretical calculations indicated that the formation of composite ferrites was thermodynamically feasible over 1085 °C. In the oriented phase reconstruction, the symbiotic structure of the VTM was reconstructed via MnO₂ addition at 1150 °C, and almost all the Fe, Mn, Ti, and V were concentrated in the composite ferrites, in which the Ti and V were doped in the octahedral structure (B site) of spinel-type crystalline structure. The as-purified composite ferrite material from the VTM+80%MnO₂ mixture roasted at 1150 °C for 2 h showed good electromagnetism performance. A minimum RL peak of ?50 dB was obtained at a veneer thickness of 11 mm, and the RL value less than ?20 dB had a big frequency bandwidth of 9 GHz (frequency range of 8 GHz–17 GHz). It's inferred that this low-cost and abundant composite ferrite material can be economically applied in the construction industry. This work provided a clean and higher-value application of abundant refractory polymetallic VTM resources.