释能降压技术在野三关隧道中的应用

在溶腔处理中,宜万铁路首次采用释能降压施工技术,成功降低溶腔水位,对施工安全风险进行科学研究,确保施工安全。     

我国新能源汽车零部件发展必须解决7大问题

在政府主导下的新能源汽车发展热潮中，我国新能源汽车零部件受整车带动，技术水平得到一定提升，市场规模得以扩大，产业化取得一定进展。文章指出，我国新能源汽车总体上与国际先进水平仍有一定差距，特别是在关键材料和零部件的配套能力方面、关键技术的研发水平以及整车的性能等方面有待于进一步提高。为使新能源汽车零部件得到又好又快发展，必须着手解决7大问题。政府应加大支持力度，调动各方面积极性，在最短的时间内实现我国新能源汽车的跨越式发展。     

我国重型汽车车桥历史、现状及发展趋势

简要介绍我国重型汽车车桥的发展历史和现状,主要制造商及其产品,技术发展水平,对比国外先进车桥技术,分析和总结我国重型汽车车桥的发展趋势及发展对策。     

基于MR阻尼器的船用隔离器系统试验研究

随着船舶技术的发展，现代船舶对船用隔离器系统提出了越来越高的要求，即船用隔离器系统应同时具备低频减振和高频抗冲击的能力，这是传统的船用减振器系统所无法做到的．为了解决此问题，本文提出了一种新的船用隔离器系统，该系统由钢丝绳弹簧和磁流变阻尼器相并联组成．文中对该船用隔离器系统的减振和抗冲击性能进行了模型试验研究。减振试验的激振力频率为1-15Hz，力幅为2．94．11．76kN；冲击试验的最大冲击输入加速度为20g，脉宽为10ms，减振试验和冲击试验均采用MTS液压加载系统来进行．试验结果表明，该船用隔离器系统具有较好的减振效果，使用了MR阻尼器后系统得共振峰值被明显的削弱；在冲击试验中，冲击响应的衰减速度随着MR阻尼器的阻尼增加而明显加快，但是MR阻尼器再冲击瞬间的出力特性明显与低频振动情况下不同，MR阻尼器的出力表现为受控制电流强度影响不大．     

Influence of slip boundary on flow separation and drag of flow past bluff body at high Reynolds numbers北大核心CSCD

［Objectives］Flow separation increases the drag and noise of underwater vehicles, and influences the controllability of their control surfaces. Therefore, the influence of slip caused by superhydrophobic surfaces on drag reduction and flow separation is studied. ［Methods］A partial slip boundary condition is developed, and the flow around a circular cylinder and foil with a slip boundary at high Reynolds numbers are numerically simulated. ［Results］The results show that the when the slip length increases, the flow around the cylinder goes through three stages: the turbulent Kármán vortex street, laminar Kármán vortex street and non-separation Stokes flow. The drag coefficient increases first and then decreases, and the vortex shedding frequency increases. For flow around a foil, the separation position moves downstream until the separation region disappears when the slip length increases, and the drag coefficient decreases while the lift coefficient increases. ［Conclusions］The results of this study show that for flow past bluff body at high Reynolds number, the slip boundary can control flow separation and reduce drag effectively, providing technical support for the application of superhydrophobic surfaces for the flow control of underwater vehicle appendages. © 2022 Journal of Clinical Hepatology. All rights reserved.     

Onboard tuning of vessel seakeeping model parameters and sea state characteristics

It is essential for a safe and cost-efficient marine operation to improve the knowledge about the real-time onboard vessel conditions. This paper proposes a novel algorithm for simultaneous tuning of important vessel seakeeping model parameters and sea state characteristics based on onboard vessel motion measurements and available wave data. The proposed algorithm is fundamentally based on the unscented transformation and inspired by the scaled unscented Kalman filter, which is very computationally efficient for large dimensional and nonlinear problems. The algorithm is demonstrated by case studies based on numerical simulations, considering realistic sensor noises and wave data uncertainties. Both long-crested and short-crested wave conditions are considered in the case studies. The system state of the proposed tuning framework consists of a vessel state vector and a sea state vector. The tuning results reasonably approach the true values of the considered uncertain vessel parameters and sea state characteristics, with reduced uncertainties. The quantification of the system state uncertainties helps to close a critical gap towards achieving reliability-based marine operations.     

基于生产降本提效的船舶焊缝设计优化

为降低生产成本及提高施工效率,结合现有生产工艺的特点,通过研究入级船级社规范对焊缝设计的要求,考虑焊缝设计的经济性及可操作性,建立有效的焊缝设计优化工作机制,在详细设计阶段和生产设计阶段实现焊缝设计优化。优化的焊缝设计可充分利用现有资源,减少额外的生产投入,降低生产综合成本。将降低施焊难度及推广自动焊的设计理念融入焊缝设计中,在提高焊接效率的同时,产品焊缝的焊接质量特别是外观成形质量可得到保证,减少焊缝的补焊及打磨工作,提高产品的整体生产效率。     

沥青混凝土路面应用温拌技术的经济节能环保探讨

文章以贵州省江口至玉屏高速为例,介绍了沥青混合料温拌技术的应用现状和技术优势,从造价、节能、减排三个方面重点研究了沥青混合料温拌技术与热拌技术分析比较。得出结论:采用温拌技术对路面造价影响较大,增幅达到60%~80%,节约能源消耗30%,减少有害气体排放达到50%。因此,应着力研发一种价格低廉性能良好的温拌技术,使其更广泛地应用于沥青路面建设,从而建设"资源节约型"、"环境友好型"社会,共创国家生态文明建设。     

Measuring transport related CO2 emissions induced by online and brick-and-mortar retailing

We develop a method for empirically measuring the difference in transport related carbon footprint between traditional and online retailing (“e-tailing”) from entry point to a geographical area to consumer residence. The method only requires data on the locations of brick-and-mortar stores, online delivery points, and residences of the region’s population, and on the goods transportation networks in the studied region. Such data are readily available in most countries. The method has been evaluated using data from the Dalecarlia region in Sweden, and is shown to be robust to all assumptions made. In our empirical example, the results indicate that the average distance from consumer residence to a brick-and-mortar retailer is 48.54 km in the studied region, while the average distance to an online delivery point is 6.7 km. The results also indicate that e-tailing increases the average distance traveled from the regional entry point to the delivery point from 47.15 km for a brick-and-mortar store to 122.75 km for the online delivery points. However, as professional carriers transport the products in bulk to stores or online delivery points, which is more efficient than consumers’ transporting the products to their residences, the results indicate that consumers switching from traditional to e-tailing on average reduce their transport CO₂ footprints by 84% when buying standard consumer electronics products.     

基于工作流和快速开发平台技术的企业节能减排项目管理系统设计

以工作流技术为核心对企业节能减排项目管理系统进行建模,从而使项目管理的业务逻辑和具体功能独立开来,达到项目管理的统一、有序的管理,提高管理系统的兼容性和整体协作性,使系统的组织更顺畅,工作流程更灵活、适应性更强。采用快速开发平台技术,通过参数定制的方式进行开发,相较于传统的编程开发模式,通过对智能报表、数据维护、MVC业务控制和其他参数的管理,可以方便、快速、高质量地开发复杂的业务系统。