基于单片机的车载酒精探测及安全控制系统的设计与实现

本文详细介绍了一种利用酒精传感器、A／D转换器、单片机、电子锁实现的车载酒精探测系统的硬件和软件实现方法。该系统以单片机为核心，配以检测电路、控制电路、报警电路，从而实现智能车载安全控制服务。由于具有设备检测的主动判断能力，因此具有较高的实用价值。     

Reduced meteoric smoke particle density at the summer pole – Implications for mesospheric ice particle nucleation

Noctilucent clouds (NLC) and polar mesospheric summer echoes (PMSE) are phenomena that occur in the summertime polar regions due to the presence of ice particles around the mesopause. That ice particles are able to form in a region with such low water vapour concentration as the mesopause is noteworthy. Even though the summer mesopause is the coldest region on Earth, temperatures are generally not low enough for homogeneous nucleation to occur, which necessitates the presence of pre-existing condensation nuclei. The nature of these nuclei has long puzzled the scientific community and many candidates have been suggested, such as particles of meteoric origin, ion clusters, sodium bi-carbonate, sulfate aerosols and soot particles. Out of these the so-called “smoke particles”, i.e. particles re-condensed from ablated meteoritic material, have long been considered the most likely. Generally, it has been believed that these particles exist in numbers of the order of thousands per cubic centimetre at the mesopause. This belief is based on 1-dimensional studies of meteoric material. A recent 2-dimensional model study, which includes the atmospheric circulation from summer to winter pole however, suggests much lower number densities at the summer mesopause. We here investigate the implications of low number densities for the formation of ice particles. We find that even though resulting ice particle distribution may produce typical NLC brightness, the number density of ice particles is not consistent with what is expected for NLC and PMSE. In particular, it is much lower than the ice particle concentration (>1000 cm⁻³) typically expected to explain the “electron bite-outs” that are frequently observed in the vicinity of PMSE’s. We therefore re-examine the assumptions and parameters that determine the smoke distribution. We show that even though the number of condensation nuclei at the polar summer mesopause can be increased within the uncertainties, the results in most scenarios remain insufficient. We show that charged particles, perhaps in combination with significant deviations from the mean mesospheric state, may be necessary for condensation of ice particles in the polar summer mesosphere. Hence, we raise the question whether the conventional ideas of nucleation on meteoric smoke, which are used in current mesospheric ice models, are correct.     

阵列NaI（T1）探测器γ能谱合成方法探讨

介绍两路或多路NaI（T1）探测器γ能谱数据的合成方法及初步成果，以“特征峰叠加”的方法对^133Cs和^60Co的仪器谱进行单峰和双峰的叠加试验，为天然γ能谱合成提供依据。实验表明，“特征峰叠加”的方法可较好地反映各仪器谱合成前的特性，有很好的应用前景。     

Characteristics of piezoelectric lead zirconate titanate multilayered detector bombarded with hypervelocity iron particles

A cosmic dust detector is currently being developed using a piezoelectric lead zirconate titanate (PZT) element. The characteristics of the multilayered detector (MD), which was composed of one hundred PZT disks, were investigated by bombarding it with hypervelocity iron particles supplied by a Van de Graaff accelerator. It was confirmed that there was a linear relationship between the signal amplitude observed from MD and the momentum of the particles. As compared with the single-layered detector (SD) that was composed of one PZT disk, it was found that the sensitivity of MD was ∼3 times higher than that of SD within the limits of the experimental conditions.     

HVDC直流场强仪相敏检波器分析与设计

地面合成电场是高压直流（HVDC）输电线路电磁环境的一个重要指标,测量该电场时需要同时测量其大小和极性。一般测量电场极性的方法是使用相敏检波器。传统的相敏检波器存在因相位不同步而导致检波误差较大的问题,影响了测量结果的准确性。本文从直流场强仪的原理出发,针对传统方式的弊端,设计了相敏检波器电路,基于该电路的工作原理分析了相位不同步所引起的检波误差,并采用全通滤波器补偿相位差。实验证明,该电路能够灵活、准确地补偿相位误差,从而解决传统设计方法中相位不同步的问题,实现了全波检波,进而分辨电场极性,满足了地面合成电场测量的需求。     

BP神经网络在火灾烟气危害性分级中的应用

建筑物发生火灾时，燃烧产生的高热和有毒、有害气体对人构成很大威胁。本文利用ＢＰ神经网络对火灾烟气危害性进行分级，介绍了神经网络模型的结构、学习过程和算法。实例计算表明：利用神经网络对烟气危害性分级是合理可行的，具有一定的实用价值。     

提高二总线火灾报警系统带载能力的研究

二总线火灾报警系统是由内一些生产厂家近年推出的一种高新技术产品，相对一般三总线、四总线火灾报警系统来说，它给工程设计，安装及使用带来极大方便，但也存在单回路带栽能力普遍低于三总线和四总线的缺点。本文从尽可能地减少探测器的工作电流入手，来提高二总线火灾报警系统的带载能力，达到了预期的效果。     

宽带微波检波器的研制

宽频带晶体检波器采用混合集成工艺，用热压键合的方法把低势垒肖特基检波二极管的管芯焊接在微带电路上。整个电路制作在一个４ｍｍ×１２ｍｍ×０．３ｍｍ的三氧化二铝陶瓷基片上，并安装在一个圆柱型８．５ｍｍ×３５ｍｍ金属盒体内。射频联接应用ＳＭＡ接头，配有ＳＭＡ—Ｎ型转换接头。为了获得平坦的频率响应和低的输入驻波比，采用了一个Ｒ—Ｌ并联支路和“Ｔ”型匹配网络，从而使检波器在０．０１～１８ＧＨＺ频带内驻波比＜１．５，频率响应起伏＜±０．５ｄＢ，采用的Ｒ—Ｌ并联支路和“Ｔ”型网络亦可用于其它微波电路，以改善微波部件的性能。     

少烟高固体含量丁羟推进剂配方研究

通过理论计算和初步实验，证实少烟高固体含量丁羟推进剂是实用的。研究表明，铝粉含量对Ｉ＾０ｓｐ、燃气中Ａｌ２Ｏ３含量、ρ有显著影响，降低铝粉含量，比冲大幅度下降；ＲＤＸ代替部分ＡＰ，烯气中ＨＣ１、Ｈ２Ｏ含量降低，但（ＣＯ＋Ｈ２）含量增加，增加了燃气的二次火焰，低铝粉配方中，ＲＤＸ不能提高比冲；增加固体含量，能明显提高比冲和密度，是提高能量特性的有效途径；提高压强，比冲增加，燃气中Ｈ２Ｏ％和ＣＯ＋Ｈ２     

高压燃烧室的冒烟测量

在单头部主室件上进行的高温高压试验研究中，冒烟是研究发动机排放特性的一个参数。为了避免直接加热器所产生的燃气中的冒烟对主燃烧室冒烟测量带来的误差，该冒烟测量是在主燃烧室常温下进行的。最后根据试验数据校验与之类似燃烧室冒烟经验模型。经验模型根据GE公司的F101发动机燃烧室的冒烟经验模型得出SN8＝2．62＋0．853[ln(Ss）]。在压力范围为2．0－3．2MPa之内，试验数据与经验模型的计算结果吻合较好。但是试验研究发现，燃烧室进口空气压力增高，冒烟显增加。因而，该模型不能应用到3．8MPa以上的高压力范围。