推土机进气系统匹配设计及应用

推土机工作环境恶劣,工作强度大,进气系统是影响发动机工作可靠性及使用寿命的关键部件。根据作者多年的设计经验,本文着重阐述推土机进气系统匹配方法及整机进气系统合理布置结构。     

丰田8A发动机进气道的优化

在四冲程汽油发动机机中，进气涡流及滚流对发动机燃料的燃烧具有较大的影响，从而影响着发动机的动力性、经济性和排放性能等。本文以丰田8A发动机作为研究对象，对其进气道的形状进行优化，使获得较好的进气涡流及滚流强度，改善发动机性能。     

山推机械全新“V系列”叉车2013盛装起航

山推叉车"V系列"叉车将在2013年首先推出V-SF30/30T等系列车型。V-SF30/30T叉车是山推"V"系列叉车的"先锋产品",山推V系列所属其他产品将陆续与广大叉车用户见面。山推叉车V-SF30/30T继承了山推叉车一贯的高品质特性,整车进行了最大程度的优化,提高了作业效率,降低了油耗。整机工艺结构更加合理,结构紧凑,起重能力强,故障率低,可维护性好,维修保养更方便。山推V-SF30/30T叉车通过对整机重心的降低使整机稳定性更强,操作更加舒适灵活;通过对进气系统优化,大幅提高进气效率,动力系统更加持久耐用;整机内部空间分配合理,     

蓄水期面板堆石坝动力特性研究

本文根据现场动力试验结果，分析并总结了面板堆石坝蓄水期堆石体的动力性质及坝体的自振特性变化规律。首次在面板上测出动水压力的分布，完善了面板堆石坝抗震性能研究。     

基于多板系统的隧道刚性路面有限元分析

本文通过对带接缝多板系统和地基的耦合分析来研究隧道刚性路面板的性能，研究中把地基假定为文克勒地基，路面板间的接缝假定为剪切弹簧单元，并用压缩矩阵简化法解算多板系统，编制了有限元分析程序，此程序可得到隧道路面板的荷载－弯沉曲线，结合无破损弯沉检测法可判断隧道路面性能。     

列车下底板进气防尘结构的研究

目前列车新风进气的方式有上部进气和下部进气2种,当采用下部进气方式时,沿途的杂物在列车高速运行时容易从风口进入空调送风系统,影响机组性能,因此在常规过滤器之前需设置防尘结构.对2种底板进气防尘结构样件进行了研究,通过实验和计算确定了2种防尘结构的阻力特性和滤尘性能,并结合列车运行条件比较了各结构的优缺点.结果表明,单层孔板结构的阻力低于多层包边内嵌式钢丝滤网,且单层孔板不易积聚灰尘,清洗方便,更适合作为列车防尘结构.该研究结果为列车底板防尘结构的设计提供依据,对提高列车空调机组的性能、改善车厢内的空气品质具有现实意义.     

ZL50轮式装载机液压系统的改进设计

液压系统是装载机的重要组成部分。其性能好坏，与整机匹配是否合理，对装载机的整机性能有着直接影响。本文根据ＺＬ５０轮式装载机的使用情况，对其液压系统进行分析，从理论上指出了ＺＬ５０轮式装载机的液压系统存在的问题和与整机匹配上的不足，并对其进行改进设计。     

利用冰蓄冷技术提高燃气轮机的发电功率和效率

燃气轮机的性能与环境温度密切相关，环境温度越高，燃气轮机的出力越低，因此，降低燃气轮机的进气温度，可提高其发电功率与效率。介绍了利用冰蓄冷技术降低燃气轮机进气温度进而提高出力的方法，并对发电容量为42MW的单循环燃气轮机电厂作了模拟分析。     

山推推出SF160型内燃平衡重式叉车

SF160型内燃平衡重式叉车整机总体设计先进、结构合理。底盘采用了国际主流配置，整机质量可靠、性能先进。发动机采用康明斯QSB6．7全电控电喷式发动机，符合欧Ⅲ排放标准，动力强劲，性能先进，     

2014年中国4K×2K电视出货量增长迅速

<正>随着4K×2K电视从早期只有小众接受到如今越来越大众化,人们对4K×2K电视产生了狂热的兴趣。特别是在中国,价格的急速下降更推动了人们对4K×2K电视的追捧。NPD DisplaySearch全球电视研究总监Paul Gagnon表示:"随着需求急速增长,2014年4K×2K电视液晶显示面板厂商和整机厂商的产量预计将有大幅增长。面板厂商计划在该年生产近2,700万片4K×2K电视面板,然而品牌厂商对终端市     

Indoor inhalation intake fractions of fine particulate matter: review of influencing factors

Exposure to fine particulate matter (PM_2.5) is a major contributor to the global human disease burden. The indoor environment is of particular importance when considering the health effects associated with PM_2.5 exposures because people spend the majority of their time indoors and PM_2.5 exposures per unit mass emitted indoors are two to three orders of magnitude larger than exposures to outdoor emissions. Variability in indoor PM_2.5 intake fraction (iF_in,total), which is defined as the integrated cumulative intake of PM_2.5 per unit of emission, is driven by a combination of building‐specific, human‐specific, and pollutant‐specific factors. Due to a limited availability of data characterizing these factors, however, indoor emissions and intake of PM_2.5 are not commonly considered when evaluating the environmental performance of product life cycles. With the aim of addressing this barrier, a literature review was conducted and data characterizing factors influencing iF_in,total were compiled. In addition to providing data for the calculation of iF_in,total in various indoor environments and for a range of geographic regions, this paper discusses remaining limitations to the incorporation of PM_2.5‐derived health impacts into life cycle assessments and makes recommendations regarding future research.     

Experimental study on a residential temperature-humidity separate control air-conditioner

According to the temperature and moisture characteristics and current problems experienced in the Yangtze River Area, a temperature-humidity separate control air conditioner was developed. This unit can remove indoor sensible heat and latent heat load separately, and adjust indoor temperature and humidity respectively, thus improve indoor comfort and reduce energy consumption. The air-conditioner consists of an air cooling evaporator and a water cooling evaporator. Orthogonal experiments were designed to study the influence of outdoor temperature, indoor temperature, indoor humidity, compressor frequency, and refrigerant distribution ratio in air cooling evaporator (RDRAE) on the unit performance. The results showed that the dehumidification capacity ranged from 0 to 4.02 kg/h; the EER ranged from 2.71 to 4.57; the cooling capacity ranged from 6822 to 13,080 W. The results can help to make the control logic of the unit, and be used as the basis of energy consumption calculation. Units with temperature and humidity separate control could save about 15.6% of the cooling energy consumption against traditional residential air-conditioner, and 47.8% against the traditional residential air-conditioner that could control both indoor temperature and humidity.     

Inhalation intake fraction of pollutants from episodic indoor emissions

The intake fraction is the attributable pollutant mass inhaled by an exposed population per unit mass released from a source. In this paper, mathematical models are combined with empirical data to explore how intake fraction varies with governing parameters for episodic indoor pollutant releases, such as those from cleaning, cooking, or smoking. Broadly, the intake fraction depends on building-related factors (e.g., ventilation rate), occupant factors (e.g., occupancy), and pollutant dynamic factors (e.g., sorption). In the simple case of the episodic release of a nonreactive pollutant into a well-mixed indoor space with steady occupancy and constant ventilation and breathing rates, the intake fraction is the ratio of the occupants’ volumetric breathing rate to the building's ventilation flow rate. Factors such as incomplete mixing, time-varying occupancy, and sorptive interactions modify this basic relationship.     

Improved indoor thermal comfort during defrost with a novel reverse-cycle defrosting method for air source heat pumps

When an air-source heat pump (ASHP) unit is used for space heating at a low ambient temperature in winter, frost may be formed on its outdoor coil surface. Frosting affects its operational performance and energy efficiency, and therefore periodic defrosting is necessary. Currently, the most widely used standard defrosting method for ASHP units is reverse-cycle defrost. During a standard reverse-cycle defrosting process, the indoor coil in an ASHP unit actually acts as an evaporator, therefore, no heating is provided and hence indoor air temperature in a heated space can drop. Furthermore, a longer period of time is needed before space heating can become available immediately after the completion of defrosting. Consequently, occupants’ thermal comfort may be adversely affected. To improve the indoor thermal comfort for occupants during reverse-cycle defrosting, a novel thermal energy storage (TES) based reverse-cycle defrosting method has been developed and the improvement to occupants’ thermal comfort experimentally evaluated and is reported in this paper. Comparative experiments using both the novel TES based reverse-cycle defrosting method and the standard reverse-cycle defrosting method were carried out. Experimental results and the evaluated indoor thermal comfort indexes clearly suggested that when compared to the use of standard reverse-cycle defrost, the use of the novel reverse-cycle defrosting method can help achieve improved indoor thermal comfort, with a shorter defrosting period and a higher indoor supply air temperature during defrosting.     

家用组合体空调器若干技术问题的研究

根据市场需求，研制开发了一种家用组合体空调器，这种空调器有室内机和室外机，由室内机接出风管将空气送到各空调房间，房间内可根据需要任意调节风量。对空调器的节流机构运行、双压缩机联合运行、快速除霜等进行了试验，并评价了储液器与汽液分离器的综合效果，给出了有关设计和试验数据，对实验现象进行了分析。     

热泵型一拖二变频空调器的开发

将国内外最新的变容量控制、电子膨胀阀控制、室内外机独立解耦控制和智能旁通除霜控制等控制方法与计算机仿真优化设计应用于热泵型变频一拖二空调系统的开发,给出了系统的原理、结构,并进行了实验研究。结果表明,系统运行稳定可靠,性能系数达到国内同类产品的领先水平,并超过了国家单元分体热泵空调器的节能标准。也为多元变容量空调系统奠定了理论与实验基础。     

Field performance measurements of a heat pump desiccant unit in heating and humidification mode

In this study, a novel self-regenerating electric vapor compression heat pump desiccant (HPD) unit operated in the heating and humidification mode during the winter season is introduced. The HPD unit was installed in an office suite for the field test. The performance of the HPD unit and the provided indoor conditions were measured over a wide range of operating conditions. The target indoor humidity ratio was set to 4.4 g/kg, which is the minimum required indoor humidity ratio for a comfortable indoor environment indicated in the ASHRAE winter thermal comfort zone. The seasonal comparison revealed that even though 77.7% of all outdoor humidity ratio data was lower than 4.4 g/kg, 78.2% and 85.8% of all the indoor humidity ratio data of each room were found to be higher than 4.4 g/kg. In addition, due to the significant sensible capacity of the HPD unit, the indoor temperatures could be maintained within 20-25 °C. These results prove that the HPD unit not only properly humidifies the indoors without using any additional water source, like the conventional humidifier, but also helps to keep the indoor temperature at the desired temperature levels.     

Microorganisms and particles in AHU systems: Measurement and analysis

In this study, for better understanding the practical removal effect of air handling unit (AHU) system on airborne microorganisms (including bacteria and fungus) and particles and microbial growth, the samples of microorganisms and particles in 10 air handling unit (AHU) systems including fan coils and indoor air were collected and analyzed in air and component surfaces of such systems in two large public buildings. It is found that the removal efficiency is of the highest for bacteria 73.9% and the lowest for particles (0.5–2 μm) 24.4%. The surface concentration of equipment bacteria is 29 CFU/cm² and fungi 137 CFU/cm². Five of 10 systems have higher fungi concentrations on air intake than that on diffuser. The results also show that the central air supply system with common components (e.g., pre-filter and bag filter) has difficulty to achieve/maintain good performance once microorganisms and particles exist, especially for particle size D ≤ 3.3 μm. The size distribution has large influence on removal efficiency. The microbial growth on surfaces of duct and equipment was noticed and may be transferred into indoor air. This will decrease the indoor air quality and lead to adverse health effect.     

Model-based commissioning for filters in room air-conditioners

This paper proposes a model that can estimate filter resistance using estimated air-conditioner indoor unit air flow rate, which is tightly related to filter fouling conditions. Two sorts of value are used as inputs to estimate air flow rate. One is the power consumed by the fan in the indoor unit of a room air-conditioner and the other is the thermal performance of a room air-conditioner. For the room air-conditioners that the real-time indoor unit fan power consumption is available, fan power consumptions are used as inputs to estimate filter resistance. For the room air-conditioners that are equipped with refrigerant pressure and temperature sensors, this model estimates filter resistance using refrigerant pressure and temperature, air temperature or enthalpy difference between supply and indoor air. This model was validated using a really running multi-evaporator Gas-engine Heat Pump (GHP) system. The maximum and average difference between estimated and measured filter resistance are 12.72% and 5.89% when using the fan power consumption as inputs. When using the air-conditioner thermal performance data, the maximum and average estimation errors are 13.12% and 5.96%. The validation results show that this model is accurate enough for estimating filter resistance. Based on this model, the method for commissioning filters in air-conditioner is discussed. This method is useful for automatically estimating filter resistance and reminding users timely to clean or replace a filter to prevent wasting energy and to maintain desirable indoor environment.     

制冷剂配管长度对全新风风管空调(热泵)机组性能影响的实验研究

本文通过进行全新风风管送风式空调(热泵)机组室内外机制冷剂配管长度对机组性能影响的实验,总结了机组制冷量、EER、排气压力、吸气压力、排气温度、制冷剂配管压降等参数随制冷剂配管长度变化的规律,分析了制冷剂配管长度对全新风风管送风式空调(热泵)机组性能影响的特点。实验研究的结果为机组设计、配置及工程应用提供了有价值的参考。