Structural Health Monitoring by Piezo–Impedance Transducers. II: Applications

This paper, the second in a two-part series, presents a new methodology for structural identification and nondestructive evaluation by piezo–impedance transducers. The theoretical development and experimental validation of the underlying lead–zirconium–titanate (PZT)–structure interaction model was presented in the first part. In our newly proposed method, the damage in evaluated on the basis of the equivalent system parameters “identified” by the surface-bonded piezo–impedance transducer. As proof of concept, the proposed method is applied to perform structural identification and damage diagnosis on a representative lab-sized aerospace structural component. It is then extended to identify and monitor a prototype reinforced concrete bridge during a destructive load test. The proposed method was found to be able to successfully identify as well as evaluate damages in both the structures.     

Wave propagation in delaminated beam

The wave propagation model investigated herein is based on the known fact that material discontinuities affect the propagation of elastic waves in solids. The change in certain material characteristics, such as a local change in stiffness or inertia caused by a crack or the presence of material damage, will affect the propagation of transmitted elastic waves and will modify the received signal. Wave frequencies associated with the highest detection sensitivity depend, among other things, on the type of structure, the type of material, and the type of damage. This paper presents a method of wave propagation, which can be further used to detect small delaminations in beam-like structures. The considered beam is modelled by spectral finite elements.     

致密油成藏主控因素对比及意义——以鄂尔多斯盆地长7段与松辽盆地扶余油层为例

致密油属于非常规油气领域,致密油的勘探开发是油田增储上产的关键因素。以鄂尔多斯盆地长7段致密油和松辽盆地扶余油层为代表的致密油研究取得了一系列的成果。从地质背景、烃源岩特征、储集空间、成藏动力等方面,将鄂尔多斯盆地长7段与松辽盆地扶余油层致密油的成藏机理和富集规律进行系统对比。结果显示,两者在烃源岩条件、储集空间、成藏动力等方面具有很大的相似性,但在成藏模式上存在一定差异：长7段烃源岩与储层是互层共生关系,属于源内成藏;而扶余油层的烃源岩位于储层之上,属于典型的上生下储,源下聚集。两者都具备致密油成藏的地质条件,可以形成具有工业价值的致密油藏,是我国非常规油气勘探领域的有利区带。     

热障涂层的破坏方式及影响因素

为提高涡轮发动机前燃气进口温度或加力燃烧室温度而采用的热障涂层技术是近年来国际高温涂层领域最活跃的研究课题之一,并且在西方的一些先进发动机上采用了热障涂层技术。然而试验或使用结果表明,热障涂层过早剥落失效现象仍存在。热障涂层在高温下服役较长时间,其粘结层与基体将遇到高温氧化问题,使其成为热障涂层最典型的损伤模式。燃料中含Ｎａ 和Ｓ 等杂质,以Ｎａ２ＳＯ４形式沉积在高温部件上,造成热障涂层的热腐蚀。夹杂硬质颗粒的气流撞击涂层表面,可形成腐蚀。此外,外界大颗粒物体损伤热障涂层也是一个严重问题。研究热障涂层退化机制有利于指导热障涂层制备工艺,使热障涂层长期稳定使用。为此,综述了近年来有关热障涂层的退化方式及影响因素,以期报道最新的研究成果     

神头一电厂 5-2 联变损坏原因浅析

根据神头一电厂５—２联变损坏的引发原因和变压器损坏情况,对损坏原因作了简要分析,并提出了一些改进意见。     

致密油成藏主控因素对比及意义——以鄂尔多斯盆地长7段与松辽盆地扶余油层为例

致密油属于非常规油气领域,致密油的勘探开发是油田增储上产的关键因素。以鄂尔多斯盆地长７段致密油和松辽盆地扶余油层为代表的致密油研究取得了一系列的成果。从地质背景、烃源岩特征、储集空间、成藏动力等方面,将鄂尔多斯盆地长 ７段与松辽盆地扶余油层致密油的成藏机理和富集规律进行系统对比。结果显示,两者在烃源岩条件、储集空间、成藏动力等方面具有很大的相似性,但在成藏模式上存在一定差异：长 ７段烃源岩与储层是互层共生关系,属于源内成藏;而扶余油层的烃源岩位于储层之上,属于典型的上生下储,源下聚集。两者都具备致密油成藏的地质条件,可以形成具有工业价值的致密油藏,是我国非常规油气勘探领域的有利区带。     

重庆磨心坡龙潭组沉积环境与聚煤规律研究

通过野外地质调查及钻探取芯的方法,详细地观察磨心坡勘查区上二叠统龙潭组的岩性、生物化石及沉积构造特征,并应用沉积环境分析与聚煤规律的理论,研究该区的沉积环境和聚煤规律.本区龙潭组成煤沼泽直接发育在潮坪上,煤层厚度不大,但层位稳定,且分布广,易于对比,可采煤层多为高灰、中高-高硫煤.研究表明,该区共经历了10次海侵和11次海退沉积,泻湖-潮坪-台地环境交替出现,主要系海陆交互相含煤构造,属局限海碳酸盐岩台地泥炭坪聚煤环境.研究成果可为磨心坡煤矿开展接替资源勘查提供理论依据和找矿方向.     

Formation cross sections of nuclei with (n,2n) reactions

Ｆｏｒｍａｔｉｏｎｃｒｏｓｓｅｃｔｉｏｎｓｏｆｎｕｃｌｅｉｗｉｔｈ（ｎ，２ｎ）ｒｅａｃｔｉｏｎｓＣｈｅｎＸｕｅＳｈｉ，ＸｉｅＫｕａｎＺｈｏｎｇ，ＺｈｏｕＳｈｅｎｇＭｏ，ＹａｎＱｉｎｇＱｕａｎ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＮｕｃｌｅ...     

Mitigation of Damages to Electric Utilities Due to High Winds

Extreme winds, hurricanes, and tornadoes produce significant damage to electrical transmission and distribution line structures. The damage produces loss of power to the affected communities for a variable length of time, depending on severity of damage. Most institutions whose operations would be life threatening in the event of power failure have emergency power. However, loss of power to both residences and businesses can have economic impact on the community in the form of temporary housing shortages and loss of business. Utility companies seem to cope with wind damage fairly well, following risk management procedures in designing for wind and in providing alternate routing for distribution lines. However, continuing research and developments are needed to keep abreast of the problem.     

浅议河北省雾霾天气的形成及防治措施

雾霾天气多次袭击我国的大部分地区,空气质量指数长期处在重度和严重污染的级别,目前雾霾天气已经成为我国一种普遍的城市气象灾害,阻碍了我国经济的可持续发展,给我国人民的身体健康造成了极大的威胁.在国际上,给我国的国际形象带来了很大的不良营养。针对河北省多个城市发生的大规模雾霾天气现象,着重阐述了雾霾的组成、形成的原因以及预防措施,为河北省频发的雾霾天气的防治提供参考性的建议.