对环路滤波器调制实现锁相环音频调频的技术     

陈良  张弘 《成都信息工程学院学报》2008,23(5)

介绍了对环路滤波器调制的一点注入式调频的实现原理、设计要点、工程设计实例及测试结果.实测表明通过对环路滤波器的一点注入式调频,是一种切实可行的性价较高的音频调频方式.  相似文献   

伶仃洋出海航道浮泥形成机制与分布特征     

莫思平  季荣耀  辛文杰  杨明远  陆永军 《海洋工程》2007,25(4):33-38

伶仃洋出海航道前后5次大规模的浮泥观测表明,航道中曾普遍发现浮泥层,但近期分布范围有所缩小;浮泥层厚一般在0.1~0.6 m之间,层厚较大的分布区主要集中在航道北段深槽区。根据浮泥分布的多年变化与洪、枯季变化分析,浮泥主要分布在航道深槽内且洪季浮泥层厚度与范围明显比枯季大,表明水动力条件相对较弱和较为丰富的细颗粒泥沙来源是浮泥形成的重要条件;浮泥层由于具有易流动性和可塑性,其形成位置、厚度与长度受潮汐作用影响明显而具有周期性变化。  相似文献   

疏浚物倾倒现状与转化为再生资源的研究--中国海洋倾废面临的困难和对策   总被引：12，自引：1，他引：12  

张和庆  谢健  朱伟  黄亦真  石萍 《海洋通报》2004,23(6):54-60

介绍了我国海洋倾废的历史和现状,分析了疏浚泥海洋倾倒面临的困难,这些困难将是今后相当长时期困扰和阻碍港口、航道和海岸海洋工程建设和发展的巨大障碍。只有将疏浚泥转化为再生资源,才能从根本上缓解海洋工程建设中疏浚泥的出路问题。把疏浚泥转化为再生资源的方法主要有3种：(1)将疏浚泥干燥、脱水后直接用于填海造地;(2)利用固化处理的化学方法,将疏浚泥转化为围海造地的填充料;(3)利用热处理的方法通过烧结将疏浚泥转化为生产轻型建筑材料和建筑陶瓷的原料。  相似文献   

A computational framework to predict the water‐leakage pressure of segmental joints in underwater shield tunnels using an advanced finite element method          下载免费PDF全文

Chenjie Gong  Wenqi Ding 《国际地质力学数值与分析法杂志》2018,42(16):1957-1975

The construction of shield tunnels under riverbeds and seabeds has considerably increased over the past decades. Due to the ultra‐high water head, water leakage through tunnel joints is a major concern during a tunnel's service life. One practical solution to prevent groundwater penetration is to implement ethylene‐propylene‐diene‐monomer gaskets at the segmental joints. However, numerical simulation of fluid pressure penetration into rubber materials remains a challenging problem in computational mechanics. Severe mesh distortions can occur due to large deformation. Consequently, a convergent solution is difficult to achieve. This paper presents an Abaqus‐based numerical framework to solve the previously mentioned problem using the implicit finite element solver. The key aspects of this framework are twofold: (1) a remesh and re‐map algorithm to overcome the excessive mesh distortion, and (2) simulation of fluid penetration into the contact interface of the gaskets to reproduce the water‐leakage process at the tunnel joints. The proposed framework is first tested to simulate the gasket‐in‐groove mechanical behavior and is then validated using experimental data and the solution produced by an explicit finite element solver. The developed framework is then adopted to predict the water‐leakage pressure at gasketed tunnel joints to illustrate the practical applications. Finally, the numerical results are compared with experimental data to demonstrate the accuracy and robustness of the proposed method and confirm its superiority and effectiveness over existing methods. This novel method can be used by tunnel designers to analyze and estimate the waterproof behavior of gasketed joints in shield tunnels without performing extensive experimental testing works.  相似文献   

复杂地层高压旋喷护壁堵漏技术的研究与应用          下载免费PDF全文

李中明  肖尧  罗婷 《探矿工程》2022,49(4):74-80

借鉴复杂地层高压旋喷护壁堵漏技术设计了一种带有特殊喷嘴的旋喷钻具,在复杂地层钻进,尤其是多层段复杂地层和深部复杂地层钻进时,泥浆护壁失效的情况下,将该钻具下到复杂孔段,利用泥浆泵将水泥浆液压入,通过旋喷钻具连续旋转喷射出高压水泥浆切割坍（垮）塌孔段孔壁,使不稳定孔壁的破碎岩土崩落掉块与水泥浆混合,候凝后,在坍（垮）塌孔段形成直径不规则的柱状水泥岩土混合体,重新钻穿后,形成有一定强度的“水泥套管”,从而达到同径护壁堵漏的目的。详细介绍了该项技术的旋喷钻具的设计、水泥浆液配方、工艺原理、技术要点、操作要领及生产应用效果。  相似文献   

泸州深层页岩气呼吸性地层井漏堵漏方法及对策分析——以Y101H3-4井为例          下载免费PDF全文

李奎 《探矿工程》2022,49(5):106-110

泸州深层页岩气储层埋深达4000 m,属于高压力地层,所钻遇石牛栏组地层岩性为含砂泥岩,本区内多口井钻遇高压裂缝气,溢流及井漏风险大,时常出现高套压事件;同时一些井存在采用高密度钻井液钻进至类似地层时发生漏失后又返吐的现象,给堵漏和钻进作业带来较大困难。针对该类呼吸性地层井漏,以Y101H3-4井为例,现场试验了一系列堵漏方法及措施,结果表明：常规堵漏工艺对呼吸性地层堵漏效果不佳,堵漏材料粒径难以匹配,易导致封门堵漏失败;针对同平台邻井实钻油气显示情况,合理降低钻井液密度有助于堵漏作业实施;油基水泥塞是解决此类呼吸性井漏最有效的工艺技术,但前提条件是确定合理钻井液密度,降低注水泥过程中的返吐量,防止水泥浆与钻井液直接接触污染。在泸州区块采取降密度+注油基水泥塞堵漏是解决呼吸性地层井漏的最佳方法,可快速解决该类地层的堵漏难题。  相似文献   

小口径绳索取心钻进在砀山地区深厚泥岩地层中的施工技术          下载免费PDF全文

王盛  潘振泉  秦正运 《探矿工程》2022,49(2):85-90

本文介绍了小口径绳索取心工艺在安徽省砀山县北部地热资源调查ZK01孔中的实践经验。厚度达600多米的水敏性泥岩地层遇水后表面水化,出现缩径和套管内壁结成虚厚泥皮现象,导致泥浆循环不畅、出现憋泵持压。根据小口径绳索取心钻进工艺特点,分析了该孔缩径特征、套管内壁结泥皮原因后,采用了液控扩孔钻头和无固相乳化抑制泥浆体系等技术取得了很好的效果。文中介绍了液控扩孔钻头原理、扩孔作业注意事项、无固相乳化抑制泥浆的维护和配制。其中液控扩孔钻头是首次在小口径绳索取心钻进工艺中采用,为后续施工类似地层提供了很好的借鉴作用。  相似文献   

Evaluation Methods and Indexes for Ultra-deep Petroleum Reservoir Preservation with Case Studies     

YUAN Yusong  WANG Guojian  HU Wenxuan  CHEN Shuping  WANG Xiaolin  ZOU Yu  WANG Xinpeng  ZHANG Rongqiang  HAO Yunqing 《《地质学报》英文版》2022,96(4):1388-1401

Following consideration of the characteristics of high temperature, high pressure and high in-situ stress in ultra-deep sedimentary basins, together with the existence of hydrocarbon phase state transformation, hydrocarbon-water-rock interaction and rock mechanical property transition at those depths, the evaluation index system for hydrocarbon preservation was established. The physical leakage evaluation indexes can be divided into three categories: the dynamic efficiency indexes of micro-sealing, caprock integrity and natural gas diffusion. The chemical loss evaluation indexes can be divided into two categories: the thermochemical sulfate reduction (TSR) index in marine gypsum-bearing carbonate strata and the thermochemical oxidation of hydrocarbons (TOH) index in clastic strata. The slippage angle and overconsolidation ratio (OCR) are the key evaluation indexes in the evaluation of the integrity of shale caprocks. TSR intensity can be quantitatively calculated by use of the ZnPVT state parameter method. The TOH strength can be used to estimate the degree of hydrocarbon chemical loss, based on the TOH-related authigenic calcite cement content or the degree of negative δ13C of authigenic calcite. For the evaluation of ultra-deep preservation in specific areas, key indexes can be selected according to the local geological conditions, instead of all indexes needing to be evaluated for every scenario.  相似文献   

井下全金属非圆齿轮动力钻具设计与可行性研究     

张伟 《地质与勘探》2023,59(1):154-161

高温高压井下动力钻具受高温的影响,其所含的橡胶等不耐高温件的寿命会大大降低,进而严重影响井下动力钻具的性能和使用寿命。而全金属非圆齿轮钻具作为一种新型的全金属容积式动力钻具对温度的变化并不敏感,十分适合高温井下工况,具有良好的发展前景。本文介绍了非圆行星齿轮马达的基本原理和特性,调研了国内外非圆行星齿轮马达的发展现状,分析了非圆行星齿轮液压马达节曲线的设计和使用寿命等关键技术。在此基础上,开展了行星马达应用于井下动力钻具的可行性研究,研制了非圆齿轮动力钻具原理样机,提出了该钻具的研发建议与方向。并通过流体力学对该钻具的端面泄漏量进行了分析,得出了对端面泄漏量影响最大的因素为端面间隙的大小,然后对改进前后的结构分别进行了有限元分析,得出改进后结构的端面间隙为+0.11～0.18μm,远小于改进前的端面间隙-0.13μm,验证了该结构的可行性。  相似文献   

Pricing carbon consumption: synthesizing an emerging trend     

Clayton Munnings  William Acworth  Oliver Sartor  Yong-Gun Kim  Karsten Neuhoff 《Climate Policy》2019,19(1):92-107

Nearly every carbon price regulates the production of carbon emissions, typically at midstream points of compliance such as power plants, consistent with typical advice from the literature. Since the early 2010s however, policymakers in Australia, California, China, Japan and Korea have implemented carbon prices that regulate the consumption of carbon emissions, where points of compliance are further downstream, such as distributors or final consumers. This article identifies the pivot towards placing the point of compliance for carbon prices further downstream as an emerging international trend, describes the designs of different prices on carbon consumption around the world, and explains the various motivations of the policymakers implementing them. Findings reveal that policymakers tend to layer prices on carbon consumption on top of prices on carbon production in an effort to improve economic outcomes by addressing incomplete pass-through of the carbon price from producer to consumer, thereby facilitating more cost-effective abatement. Policymakers also use prices on carbon consumption to reduce emissions leakage or because large producers of carbon are not within their jurisdiction. The prevalence of prices on carbon consumption will likely increase as evidenced by proposals in China and Europe.

Key policy insights

• The recent surge in the number of jurisdictions implementing prices on carbon consumption represents an emerging international trend.

• Policymakers use prices on carbon consumption in an effort to improve economic outcomes and capture environmental benefits.

• While this article offers insights that detail initial challenges and successes, whether these prices on carbon consumption actually achieve their intended goals is an academically rich topic that requires further research on individual policies.

  相似文献