γ 射线辐照对煤中自由基浓度变化和电解加氢液化的影响

利用电子顺磁共振（ESR）波谱仪对 γ 射线辐照前后的煤样进行了自由基的测试,结合气相色谱分析研究了辐照对煤结构的影响,并对辐照前后的煤样进行了电化学测试。结果表明,辐照可以促进煤中大分子烷烃链及杂原子的断裂,并产生氢气、甲烷等小分子量的气体,当辐照剂量为40 kGy 时,自由基浓度达到最大。而自由基浓度的增大有利于煤的电解加氢液化,且当辐照剂量为40 kGy 时,电流密度达到最大。     

Gas‐phase fragmentation of metal adducts of alkali‐metal oxalate salts

Upon collisional activation, gaseous metal adducts of lithium, sodium and potassium oxalate salts undergo an expulsion of CO₂, followed by an ejection of CO to generate a product ion that retains all three metals atoms of the precursor. Spectra recorded even at very low collision energies (2 eV) showed peaks for a 44‐Da neutral fragment loss. Density functional theory calculations predicted that the ejection of CO₂ requires less energy than an expulsion of a Na⁺ and that the [Na₃CO₂]⁺ product ion formed in this way bears a planar geometry. Furthermore, spectra of [Na₃C₂O₄]⁺ and [³⁹K₃C₂O₄]⁺ recorded at higher collision energies showed additional peaks at m/z 90 and m/z 122 for the radical cations [Na₂CO₂]^+? and [K₂CO₂]^+?, respectively, which represented a loss of an M^? from the precursor ions. Moreover, [Na₃CO₂]⁺, [³⁹K₃CO₂]⁺ and [Li₃CO₂]⁺ ions also undergo a CO loss to form [M₃O]⁺. Furthermore, product‐ion spectra for [Na₃C₂O₄]⁺ and [³⁹K₃C₂O₄]⁺ recorded at low collision energies showed an unexpected peak at m/z 63 for [Na₂OH]⁺ and m/z 95 for [³⁹K₂OH]⁺, respectively. An additional peak observed at m/z 65 for [Na₂¹⁸OH] ⁺ in the spectrum recorded for [Na₃C₂O₄]⁺, after the addition of some H₂¹⁸O to the collision gas, confirmed that the [Na₂OH] ⁺ ion is formed by an ion–molecule reaction with residual water in the collision cell. Copyright © 2014 John Wiley & Sons, Ltd.     

Quartz Rod Coated with Modified Silica Gel as a Source of CO and CO2 for Standard Gaseous Mixtures

Quartz rods coated with a thin layer of chemically modified silica gel have been used for the generation of a two-component gaseous standard mixture containing carbon monoxide and carbon dioxide. A new method based on thermal decomposition of immobilized compounds chemically bonded to the surface of silica gel has been used in the generation process. The oxalic acid moiety bonded to the glycydoxypropylsilylated surface of silica gel underwent decarbonylation and decarboxylation at 300°C, yielding carbon monoxide and carbon dioxide. On-line connection of a thermal desorber with the GC/FID enabled calibration of the detector following the process of methanization of CO and CO₂. The following amounts of CO and CO₂ were generated per unit length of the rod: 15.1 × 10⁻⁸ Mol cm⁻¹ (RSD = 5.71%) for CO and 34.2 × 10⁻⁸ Mol cm⁻¹(RSD = 5.16%) for CO₂.     

气相反应84/70 C_(70)(D_(5h))=C_(84)(D_2)热力学函数的计算

计算了不同温度下气相反应84／70C70（D5h）＝C84（D2）的热力学函数，讨论了C70（D5h）与C84（D2）之间相互转化的热力学条件；结果表明，温度低于2392K时C84（D2）比C70（D5h）稳定，温度高于2392K时气相中C70（D5h）比C84（D2）稳定；同时给出了气相C84（D2）的标准热力学函数。     

瞬时气压记忆型水箭的制作

利用塑料饮料瓶，胶塞，自行车气嘴及一次性注射器等材料制作一个装置，实现了水箭发射瞬时的内气压记忆，为安全发射和定量研究变质量问题提供一简便的实验演示。     

Alien Attack: A Non-Pharmaceutical Complement for ADHD Treatment

Mental health issues are among the most common health issues nowadays, with attention-deficit hyperactivity disorder (ADHD) being the most common neurobehavioral disorder affecting children and adolescents. ADHD is a heterogeneous disease affecting patients in various cognitive domains that play a key role in daily life, academic development, and social abilities. Furthermore, ADHD affects not only patients but also their families and their whole environment. Although the main treatment is based on pharmacotherapy, combined therapies including cognitive training and psychological therapy are often recommended. In this paper, we propose a user-centered application called Alien Attack for cognitive training of children with ADHD, based on working memory, inhibitory control, and reaction-time tasks, to be used as a non-pharmacological complement for ADHD treatment in order to potentiate the patients’ executive functions (EFs) and promote some beneficial effects of therapy.     

气相规则胞格爆轰波起爆与传播统一框架的几个关键基础问题研究

本文综述并分析了气相规则胞格爆轰在起爆与传播方面的研究进展,结合高温气体动力学国家重点实验室在爆轰物理方面的研究工作,进一步研究了气相规则胞格爆轰波起爆的几个关键基础问题．这些基础问题由一个机制：非线性波传播／化学反应过程相互作用机制;两个基本过程：热点起爆和化学反应带加速过程;三个关键物理状态：平衡传播状态、临界起爆状态和稳定胞格尺度等六个关键要素组成,是统一框架的主要基本元素．通过六个典型的物理算例,本文研究了这些关键物理要素的内在机制、表现特征及其客观存在性．应用气相规则爆轰起爆与传播的统一框架,我们成功地解释了目前已有的经典爆轰理论、应用CFD技术获得的多维爆轰波计算结果和实验研究观察到的胞格爆轰图像的合理性及其依据的关键物理要素．     

氧化型催化器载体长度对柴油机排放性能的影响

基于轻型柴油机台架试验平台,研究柴油机氧化型催化转化器(DOC)载体长度变化对后处理系统减排性能的影响.结果表明:适当增大DOC载体长度可提高对一氧化碳(CO)、总碳氢化合物(THC)和一氧化氮(NO)的氧化率,过量增大对氧化性能的提升有限,同时影响DOC在低温低负荷下减排效果;DOC耦合催化型柴油机颗粒捕集器(CDPF)对颗粒物数量(PN)的减排效果受DOC载体长度影响较小.从兼顾成本与性能的角度出发,适当增大DOC载体长度能有效提高减排效果,但过量增大对减排效果提升影响不大.     

焊剂带约束电弧超窄间隙焊接的气保护方法

利用焊剂带约束的电弧进行超窄间隙焊接时,采用合适的气体保护工艺十分重要.为了获得成形良好的超窄间隙焊缝,通过分析和试验确定粗扁管单侧倾斜送气的气保护方法,设计用于研究气保护效果的试验装置,并利用该装置研究气流量、喷嘴截面尺寸以及喷嘴与保护区距离对气保护效果的影响.结果表明,在气体喷嘴截面尺寸为2.5 mm×12 mm,气体喷嘴与电弧距离为20～25 mm的情况下,保证焊缝成形良好的最佳气流量为10 L/min.     

连续波DF/HF化学激光器气膜冷却式喷管流场数值分析

在连续波DF/HF化学激光器主喷管收缩段采用气膜冷却方式,从3维离散小孔注入氦气射流以隔离壁面和主气流。通过对3种气膜孔排布方式下喷管内主气流状态进行数值模拟研究,分析氦气与主气流之间的相互作用,比较了不同方式下主气流氟原子冻结效率及壁面冷却效果。考虑到DF/HF化学激光器主喷管结构尺寸较小,采用适当间隔的单排圆孔注入是现实可行的,并有望达到较好的冷却保护效果,从而提高激光器运转效率。