脱水污泥制备聚合物合成"木材"的研究

以污水处理厂脱水污泥和废塑料为主要原料 ,通过污泥处理、聚合物改性 ,采用热塑复合法可以制备出聚合物复合材料及对应的微孔材料 ,影响材料性能的主要因素有污泥形态、废塑料种类以及它们之间的质量比等参数。最终材料表现出木材的很多性能 ,是一种使污泥高附加值利用的有效方法。     

废弃日用品塑料中多溴联苯醚浸出特征及地下水健康风险

选择典型废弃日用品塑料,对特征处置场景下其PBDEs的浸出特征及健康风险进行了评价.结果表明,日用品塑料在硫酸/硝酸、醋酸和腐殖酸溶液中达到溶出平衡时,∑21PBDEs释放量分别为20.00、63.65、125.60μg·kg-1,均以BDE209为主.进入生活垃圾填埋场的释放量高于堆存和简易填埋过程,在最不利条件下距填埋场下游500 m处地下水中PBDEs最大浓度为39.67μg·L-1,居民饮用地下水产生的非致癌风险指数为2.11×10-1,其中十溴代物(BDE209)的非致癌风险指数为1.85×10-1,均小于美国标准中非致癌的可接受风险水平(1.0),表明废旧日用品塑料可进入生活垃圾填埋场处置.     

GaAs MMIC功率放大器加速寿命试验及可靠性评估

目的评估新研GaAs微波单片集成电路(MMIC)功率放大器的可靠性指标。方法用图估法和范-蒙特福特检验法对失效数据进行分布假设检验,利用贝叶斯定理估算低温度应力下无失效数据的威布尔分布参数。结果在正常工作情况下,结温为150℃时,该器件特征寿命为833 370h,10年平均失效率为1.2472×10-7/h,平均寿命为738 540 h,可靠度等于0.9时的可靠寿命为31年。结论该型器件在结温小于250℃时服从威布尔分布,结温为270℃时器件的失效机理已发生了变化,器件的各项可靠性指标满足使用要求。     

动载下高密度全尾砂胶结充填体稳定性试验研究

为研究动载下高密度全尾砂胶结充填体(HTB)的稳定性,制备直径为50 mm×25 mm的HTB试件,进行静态单轴压缩试验。首次采用分离式霍普金森杆(SHPB)装置研究HTB的动态力学性质,通过观察冲击试验后试件的破坏程度,来评判高应变率下试件的稳定性。结果表明:HTB试件波阻抗较小,对弹性应力波传播有较强的阻尼作用;在冲击载荷下,试件最大应变率可达305 s-1,动态抗压强度随着应变率的增加而增大,最大动态抗压强度为17 MPa;HTB试件的稳定性与应变率密切相关,当应变率低于10 s-1时,试件稳定性较好;当应变率为10~39 s-1时,试件产生一定的损伤裂纹,但尚有一定的残余强度;当应变率大于39 s-1时,试件完全失稳。     

特厚煤层不同开采阶段"弱-弱"结构覆岩破坏高度研究

为了确定老虎台矿特厚煤层不同开采阶段"弱-弱"结构覆岩破坏高度,以63005工作面所在区域为研究对象,构建FLAC3D数值计算模型,对研究区域水砂充填开采阶段和综采放顶煤开采阶段覆岩破坏高度进行分析,确定了覆岩破坏高度与采出厚度的关系.分别采用微震监测、EH-4探测法对研究结果进行了验证.结果表明:无论水砂充填开采阶段还是综采放顶煤开采阶段,老虎台矿"弱-弱"结构覆岩最大破坏高度均约为等效采高的8.5倍;63005工作面开采前后,覆岩破裂最大高度与油母页岩和绿色页岩的分界面密切相关,均被控制在分界面之下;覆岩破坏高度受到F18断层的影响,被约束在断层破碎带沿走向范围内;63005工作面开采后,绿色页岩层中F18断层的下盘出现离层破坏,且破坏范围呈逐步扩大的趋势.     

航天导弹装备自然环境试验方法探讨

航天导弹型号装备在研制阶段,一般需要有针对性地开展典型或极端自然环境的投放试验,以验证和评价导弹武器系统对服役期可能经受自然环境条件的适应性。针对导弹型号自然环境试验的实施过程,从试验准备、试验实施、试验结束、试验总结、试验数据收集等方面对试验关键环节进行技术或管理方法探讨,以进一步规范和指导型号自然环境试验工作的开展,提高试验效率和试验效果。     

Technical specifications for mechanical recycling of agricultural plastic waste

Technical specifications appropriate for the recycling of agricultural plastic wastes (APWs), widely accepted by the recycling industry were developed. The specifications establish quality standards to be met by the agricultural plastics producers, users and the agricultural plastic waste management chain. They constitute the base for the best economical and environmental valorisation of the APW.The analysis of the APW streams conducted across Europe in the framework of the European project “LabelAgriWaste” revealed the inherent characteristics of the APW streams and the inherent constraints (technical or economical) of the APW. The APW stream properties related to its recycling potential and measured during pilot trials are presented and a subsequent universally accepted simplified and expanded list of APW recycling technical specifications is proposed and justified. The list includes two sets of specifications, applied to two different quality categories of recyclable APW: one for pellet production process (“Quality I”) and another one for plastic profile production process (“Quality II”). Parameters that are taken into consideration in the specifications include the APW physical characteristics, contamination, composition and degradation. The proposed specifications are focused on polyethylene based APW that represents the vast majority of the APW stream. However, the specifications can be adjusted to cover also APW of different materials (e.g. PP or PVC) that are found in very small quantities in protected cultivations in Europe. The adoption of the proposed specifications could transform this waste stream into a labelled commodity traded freely in the market and will constitute the base for the best economical and environmental valorisation of the APW.     

Prenatal diagnosis and treatment of fetal long QT syndrome: a case report

We report a case of a fetus presenting with bradycardia, intermittent atrioventricular (AV) block, ventricular tachycardia (VT) and the signs of fetal congestive heart failure (ascites and scrotal hydrocele) during mid-gestation. Prenatal treatment with β-adrenergic blocker (propranolol) and digitalis glycosides was prescribed because of suspicion of long QT syndrome occurring with fetal congestive heart failure. The male baby was born at 39 weeks of gestation and showed a prolonged QT interval (QTc = 492 ms) and frequent variable AV block or alternating left and right bundle branch block, depending on the atrial rate. Prenatal administration of lidocaine failed to correct the fetal VT. Conversely, propranolol decreased the attack frequency of fetal VT. Postnatal administration of the K⁺ channel opener (nicorandil) successfully shortened the QT interval and improved the outcome. Copyright © 2002 John Wiley & Sons, Ltd.     

CESSNA172R飞机飞行操纵钢索故障原因分析

CESSNA172R飞机飞行操纵(副翼、升降舵、方向舵、襟翼)系统钢索多次发生磨损、断裂故障,严重威胁了飞行安全。根据该机型结构设计特点,通过相似机型系统类比、数据可靠性分析等方法分析了各飞行操纵系统钢索失效的主要原因,提出了预防飞行操纵钢索失效的措施。通过调整飞机的操纵钢索系统的维护周期,改进钢索的检查和维护技术,提高飞机在全寿命周期中的安全可靠性。