摘要：The sound insulation performance of railway car body structures is critical for the control of rail vehicle interior *** sound transmission loss(STL)measurements,a niche with a large depth is necessary to allow for mounting the wide range of thicknesses of railway car body panels and for the mechanical isolation of the two *** this study,two typical interior floor panels are tested in a series of mounting conditions and mechanical boundary *** change of STL results during measurement is also predicted by an STL prediction model based on the finite element *** lower frequencies,the STL results are influenced by both the mounting positions and the mechanical boundary *** higher frequencies,the STL results are mainly influenced by the mechanical boundary *** between the panel in the infinite baffle and niches at the resonance and off-resonance frequencies are *** both the effects of mounting positions and mechanical boundary conditions,the existence of the cavity amplifies the STL difference caused by the mechanical boundary conditions.

摘要：Installation of rail vibration dampers （rail dampers for short） onto rails between sleepers is one of the measures to control rail noise generation and roughness growth. Amid the rapid expansion of high-speed and underground railway networks in China, many suppliers are actively marketing and promoting their products, often giving confusing information. In this paper, a parametric study is used to investigate the effect of rail dampers on the dynamical behavior of a Chinese high-speed railway track. The Fourier transform-based method developed for analyzing dynamics of a railway track as an infinitely long periodic structure, with or without rail dampers, is applied in the investigation. It is hoped that results in this paper can help develop the understanding of the working mechanism of rail dampers, and provide useful information for product design and application.

摘要：This paper presents an investigation into the characteristics of interior noise of a Chinese high-speed train under several typical conditions. Interior noises within Vehicle TC01, which can be used as a head car or an end car, and Vehicle TP03, the third car counting from TC01, are measured for the train running at speeds from 260 km/h to 385 km/h, along two types of track including a slab track and a ballast track and either on the ground surface or in a tunnel. Data analyses are performed for sound pressure overall levels, frequency, area contributions, and possible generation mechanisms, showing how they are affected by train speed, running direction, track type, and tunnel. The results show that, whether TC01 is used as head car or end car, the interior noise characteristics in the VIP cabin are mostly related to aerodynamic noise. Differences in interior noise between tracks become smaller as the train speed increases. The effect of a tunnel on the interior noise is more important for the middle coach than that for the head coach. This study can provide a basis for noise control of high-speed trains.

摘要：成都市沱江污水处理厂一期土建规模为8×10^(4) m^(3)/d,设备安装规模为4×10^(4) m^(3)/d,采用全地埋封闭式建设。箱体内工艺流程自北向南依次布设,实现了集约化和功能分区的合理布局。针对污水特点,核心工艺采用水解酸化+改良型AAO,设计出水水质执行《四川省岷江、沱江流域水污染物排放标准》(DB 51/2311—2016)。详细介绍了该污水处理厂主要构筑物设计参数及设计亮点。自2021年11月转商运以来,该厂出水水质稳定达标。一期工程投资为66605.92万元,实际运营成本为2.241元/m^(3),主要通过节能降耗措施及污泥减量化降低了运行成本。

摘要：提出了一种基于整车噪声仿真分析的部件声学指标分解方法;将高速列车的部件声学指标按类型分为声源指标和路径指标2种主要形式,分别基于声线法和统计能量分析方法建立了高速列车的车外噪声预测模型和车内噪声预测模型,通过选定的初始参数作为计算输入,预测车外、车内噪声,并与车辆顶层声学指标进行差异化对比分析;基于声源贡献、路径贡献与参数灵敏度分析,考虑多目标优化,确定了声源部件和路径部件的声学指标。研究结果表明:噪声源的指标分解,基于整车车外噪声仿真分析,当车外噪声预测结果满足声学设计目标且设计裕量在可接受范围之内时,此时的声源参数输入即可作为一组声源指标分解结果;对于传声路径的指标分解,基于整车车内噪声仿真分析,当车内噪声满足声学设计目标且设计裕量在可接受范围之内时,此时的路径参数输入即可作为一组路径指标分解结果;当声源指标或路径指标不满足整车噪声要求时,则需要进行声源或路径的贡献分析,计算主要贡献声源或路径的参数灵敏度,通过对主要贡献声源或者路径进行修正迭代,使之最终满足声学设计目标;低噪声设计需要不断综合多项指标的反馈,合理地调整部件声学指标,确保声学指标分解满足顶层目标,且具有可行性。

摘要：基于空间核热推进(SNTP)粒子球床堆的物理模型,研究了控制鼓外径与反射层厚度、10 B富集度及厚度、栅径比与高径比、燃料球体积填充率等对粒子球床堆堆芯设计参数敏感性的影响。结果表明:反射层厚度取决于控制鼓外径的选择;10B富集度及厚度对堆芯可控性影响较小;对于所选堆芯,存在最优栅径比,增大堆芯高径比可增加堆芯径向中子泄漏率,进而提高控制鼓的控制价值;随着燃料球体积填充率的增大,堆芯keff增大,中子泄漏减少,能谱变硬,燃料球体积填充率的变化对堆芯轴向、径向中子注量率不均匀因子影响较小。本文研究结果对粒子球床堆堆芯设计参数的选择具有指导意义。

摘要：利用微波对生物质进行热解制氢是一种高效、快速、环保的技术手段,由于木质素是自然界唯一可再生的芳香碳氢资源,因此以木质素为主的林木类生物质是一种很好的制氢原料.目前制约其工业化的因素主要来自微波热点效应,因此本文通过生物质在不同微波频率下的穿透深度,对反应器进行整体建模设计,并通过正交设计仿真、CFD及HYSYS模拟来分别获得均匀温度场的工况条件、最佳反应器高径比以及工业化装置最大产品量时的操作参数.结果表明,当微波功率密度为30 W·g^(–1),物料颗粒半径为4 mm,物料堆积密度为800 kg·m^(-3),反应器高径比为2.0,水蒸气中段和末段通量分别为290和1230 m 3·h^(–1)时,可以获得最大量氢气产品且温度场均匀,此时温度场的变异系数为0.009,氢气的产量为922.98 m^(3)·h^(–1),摩尔分数为0.4781,产率为82.49%.

摘要：长周期光纤光栅(long-period fiber grating,LPFG)是一种宽带的透射型无源光子器件,在光纤通信和光纤传感领域应用广泛.本文从折射率空间调制的角度,根据栅格周期长短、折射率调制深度和栅面法线取向三个特征参数,对LPFG进行了分类并分析了其不足,定义了新型长周期光纤光栅(novel long-period fiber grating,NLPFG)概念并指出了其研究意义;阐述了典型的LPFG写制新技术,建立了NLPFG模型和设计理论;提出了NLPFG正、反向设计流程,阐述了NLPFG典型设计方法;综述了近年来NLPFG的研制及典型应用,展望了NLPFG研究的发展趋势.

摘要：为了抑制空调系统对高速列车车内噪声的影响,在风道内设置阻抗复合消声器,量化分析传声特性是高速列车低噪声设计的重要内容.基于有限元-统计能量分析(FE-SEA)混合法建立某高速列车风道消声器传声特性分析模型,对80~3150Hz频率区段的风道消声器传声特性进行预测计算.采用声学有限元法建立风道消声器声学模态分析模型,针对传递损失的峰值和谷值所在的频率区段,计算风道消声器声学模态,解释传递损失峰/谷值的成因.从提升声学性能的角度,结合工程实际情况,对风道消声器进行设计方案优选.结果表明:风道消声器具有良好的降噪作用,声学模态振型特性是传递损失峰/谷值的成因;消声器阻性特性对传递损失的影响最大,通过吸声选材优选可以最大提高传递损失18.0dB;消声器抗性特性影响相对较小,通过吸声包数量和位置的优选可以最大提高传递损失4.1dB;考虑阻抗复合优选方案,最高可以提高风道消声器传递损失18.6dB.

摘要：建立轨道结构三维实体有限元模型,同时考虑钢轨、轨下垫层、轨枕和道床,并与已有轨道结构振动模型的数值结果进行比较。结果表明,本文模型的数值结果在高频部分较合理,能够反映轨道结构高频振动特性。分析不同轨道结构参数对钢轨和轨枕振动特性的影响,这些轨道结构参数主要包括钢轨材料损失因子和钢轨质量、轨下垫层损失因子和垂向刚度、轨枕质量和损失因子、道床的刚度与阻尼特性等。分析结果表明,轨道结构参数的改变对钢轨和轨枕在不同频域范围影响不同,通过合理的轨道结构系统参数优化设置,可达到减振降噪效果。相关计算和分析结果可为低噪声轨道的设计提供依据与参考。