气动增压泵在单片晶圆清洗过程中的应用

主要分析了气动增压泵的组成和工作原理,描述了气动增压泵在单片晶圆清洗过程中的应用特点和优势.介绍了气动增压泵在应用过程中的控制方法和选用注意事项.     

Modeling improvements in booster seat use: a discrete choice conjoint experiment

Automobile crashes are the leading cause of death in children aged 1–14 years. Many children, however, are not properly restrained in safety seats that reduce serious injury and death. This study used a discrete choice conjoint experiment to study factors influencing the decision to use booster seats. Parents of 1714 children aged 4–9 years from nine Canadian provinces completed choice tasks presenting experimentally varied combinations of 15 4-level booster seat promotion attributes. Latent class analysis yielded three segments of parents. The choices of the Benefit Sensitive segment (50%) were most sensitive to the injury prevention benefits of booster seats. The choices of parents in the Context Sensitive segment (33.5%) were more likely to be influenced by installation complexity, oppositional behavior, and the prospect that their child may be teased for riding in booster seats. Parents in the High Risk segment (16.5%) were younger, less educated, and less knowledgeable about vehicle safety legislation. They anticipated fewer benefits, expected more barriers and were less likely to use booster seats. Simulations suggest that consistent enforcement coupled with advertising focusing on injury prevention and the use of booster seats by other parents would increase adoption.     

变组分法的感度试验条件及界面传爆概率计算研究

研究了变组分法所用小隔板感度试验的施主参数，并依据感度数据计算了榴－５引信序列雷管一导引药界面的传爆概率。     

某新型运载火箭助推器热试车吊装与固定方案设计

针对某新型运载火箭助推器的热试车试验,开展吊装固定方案设计,通过关键技术攻关,成功实现中国首次最大推力火箭子级热试车试验的吊装对接与固定,并且吊装固定方案安全可靠、简单易行、经济性好,为后续该新型火箭助推器发射场合练试验积累了宝贵经验。     

Discrepancies between knowledge and practice of childhood motor vehicle occupant safety in Nova Scotia—A population-based study

Objectives

To determine discrepancies between knowledge and practice of childhood motor vehicle restraints (CMVRs) and vehicle seating position amongst parents within the province of Nova Scotia.

Design

Random telephone survey.

Setting

The Canadian province of Nova Scotia.

Subjects

Four hundred and twenty-six households with at least one child under the age of 12 years, totaling 723 children.

Main outcome measures

The proportion of parents whose children who should be in a specific stage of CMVR and sitting in the rear seat of the vehicle, and who demonstrate correct knowledge of that restraint system and seating position, yet do not use that restraint system/seating position for their child (demonstrate practice discrepant from their knowledge).

Results

Awareness of what restraint system to use is good (>80%). However, knowledge of when it is safe to graduate to the next stage is low (30–55%), most marked for when to use a seatbelt alone. Awareness of the importance of sitting in the rear seat of a vehicle was universal. Discrepancies between knowledge and practice were most marked with booster seats and rear-seating of older children. Factors influencing incorrect practice (prematurely graduated to a higher-level restraint system than what is appropriate for age and weight) included lower household income, caregiver education level, and knowledge of when to graduate from forward-facing car seats and booster seats. Incorrect practice was also more commonly observed amongst children of weight and/or age approaching (but not yet reaching) recommended graduation parameters of the appropriate CMVR.

Conclusions

Discrepancies between knowledge and practice are evident through all stages of CMVRs, but most marked with booster seats. The roles of lower socioeconomic status and gaps in CMVR legislation, in influencing discrepant practice, must be acknowledged and suggest the need for targeted education concurrent with development of comprehensive all-stages CMVR policies.     

高压变频调速技术在电炉除尘风机中的应用

本文介绍了河北钢铁集团舞钢公司一炼钢厂3#LF电炉的增压风机采用北京利德华福高压变频调速技术的理论依据及其调速系统的设计,高压变频调速在使用中应注意的一些技术问题,以及产生的较好运行效果和显著经济效益。     

太阳能喷射-电压缩复合制冷系统中增压器的选型及性能预测

本文预测了在建太阳能制冷实验台的性能及影响太阳能喷射系统的因素,并且对太阳能喷射．电压缩复合制冷系统中增压器的选型做了分析,认为采用变频压缩机作为复合系统的增压器可使系统效能更优。     

增压器叶轮超速自增强技术

叙述了增压器叶轮超速自增强技术的原理,提供了两种超速工艺的工装设计方案,并通过有限元分析,提出了最佳超速转速确定的方法。     

极限工况下的管网“互联互通”改进方案

在全国天然气管道"主干互联、区域成网"(以下简称"互联互通")基础格局逐渐形成的背景下,天然气管网规模日益扩大、管道分支和气源增加,并且分布不集中、输送方向可变,使得输气方案更加灵活,可以更好地解决某些地域的供气紧张问题;但受现有站场和设备的限制,暂不能满足某些多线组合极限工况,使得"互联互通"的初衷难以全部实现。为了使得现有的各输气干线在实现"互联互通"之后可以满足更多的多线组合工况,在分析"互联互通"背景下M管网工况变化的基础上,研发了可以进行水力仿真和压气站方案制订的计算软件,并对3种极限工况下的不同输气量情况进行了可行性试算,进而基于试算结果提出了相应的管网改进建议。研究结果表明:①经验证,软件计算误差满足要求;②在M管道某处增设压气站或在某些输气站场配置压缩机组;③M管网改进调整后,可以完成大部分的多线组合极限工况,真正实现"互联互通"的输气方案。结论认为,该研究成果有助于推进全国天然气管网早日实现"互联互通"。     

低功耗超声波燃气表设计

超声波燃气表受流道结构、管径机械噪声、气体流速等因素影响,造成超声波信号衰减严重、低功耗设计实现难度大。针对这一问题,以超低功耗MSP430微处理器为核心,搭载低功耗芯片超声波模拟前端(TDC1000)和高精度计时芯片(TDC7200),构成了超声波信号发射与接收电路。提出了一种优化激励信号脉冲个数方法,以及采用定时中断和外部中断相结合的系统监控方式来实现低功耗设计,并完成了G2.5超声波燃气表的设计。通过实际测试,优化的激励信号个数能获得较好的超声波回波信号。计算结果表明,使用1节6000mAh的锂电池供电,研制的G2.5超声波燃气表正常计量工作年限可达6年,能够满足企业低功耗技术要求。