基于CEEMD的小波软阈值和粗糙度惩罚平滑技术的联合信号去噪方法

为了有效去除采集信号中的噪声,基于MEMS水听器在采集信号时混入不同噪声的情况下,提出了一种基于CEEMD的小波软阈值和粗糙度惩罚平滑技术的联合信号去噪方法。CEEMD用于将一个含噪信号分解为几个固有模态(IMFS),然后把几个固有模态和原始信号作一个线性相关分析,分为相关性高的模态和相关性低的模态。将软阈值技术应用于相关性低的固有模态,并将粗糙度惩罚平滑技术应用于相关性高的固有模态,以提取尽可能多的信息,然后把处理后的新的固有模态重构形成去噪信号。分别在仿真和真实数据的基础上进行了实验,验证了方法的有效性。结果表明,联合信号去噪方法无论在去噪效果和性能指标上都优于基于CEEMD的小波软阈值的去噪方法和CEEMD的去噪方法,克服了经验模态方法和小波软阈值去噪的不足,为进一步分析与处理信号提供参考。     

Mining, Displacement and the World Bank: A Case Analysis of Compania Minera Antamina's Operations in Peru

The transformation in the structure of the world mining industry over the last decade has opened up enormous new regions for mineral exploration and development by transnational mining companies in countries in the South. This new access has inevitably brought mining companies into conflict with local communities. With the involvement of transnational advocacy networks and new global publics, these conflicts have prompted a growing transnational debate on the principles that ought to govern mining and community relationships. One effort to provide guidance on this question comes from the World Bank's Operational Directive 4.30 on Involuntary Resettlement. This paper examines the regulatory impact of this policy upon relationships between mining companies and communities, as well as its "legitimation effect" in providing standards which, once met, can serve to certify a degree of responsible behaviour on the part of the company. The analysis of the effects of the directive is taken up in the form a case study involving a transnational mining company operating in the Andes of Peru and the local communities impacted by its land acquisition project.     

现代带式输送机的设计方法

带式输送机是现代最重要的散状物料输送设备。本文在分析常规设计方法的基础上,给出了带式输送机的优化设计方法,动态分析方法,最后给出了带式输送机的设计程序。     

Greening Displacements,Displacing Green: Environmental Subjectivity,Slum Clearance,and the Embodied Political Ecologies of Dispossession in Mumbai

In Indian cities, informal ‘slum’ settlements have long been targeted for removal as an environmental improvement strategy, despite their relatively low impact. Slum clearance has escalated with the combination of speculative development and environmental change, creating uneven precarity throughout Mumbai's neighborhoods. State agents play a direct role in slum evictions, but they do not act unilaterally. Diverse lower‐income and middle‐class residents seeking better living conditions have sometimes converged in their embrace of slum clearances and resettlements that advance elite development interests. In other moments, the dispossessing effects of market‐based and elite‐biased slum rehabilitation have fomented contestation. This article analyzes how differently situated groups emerge as ‘environmental subjects’ that embrace or contest improvement projects. It suggests three dimensions of subject formation: governing logics and discourses of urban environmental improvement, the territorial politics of informality, and differentiated embodied experiences of precarity and dispossession. Environmental subject formation is explored through two interventions that entail slum clearance—mangrove and green space conservation and an urban transport infrastructure project. Findings suggest that the connection between displacement and improvement cannot be explained through theories of environmental gentrification but require attention to the simultaneously inclusive and dispossessing regimes of postcolonial development.     

刘江黄河大桥主桥运行环境下的振动测试

本文通过对刘江黄河大桥主桥运行环境下的振动实测,得到桥梁的在不同频率下的竖向加速度、横向加速度的响应振动稳定图,扭转振型及扭转频率,判断吊杆的损伤对横、竖向振动的影响,推知桥梁目前的运行状态。     

车削细长丝杆的技术应用

车细长轴是车削的难点,而加工细长丝杆就更困难,车削细长丝杆中根据工艺要点,抓住跟刀架与中心架的使用。解决工件的热度形伸长及合理选择几何参数,问题就可解决。     

细分层注水井封隔器位移磁定位测井误差分析与控制

油田开展的精细分层注水需要对注水井封隔器在井下各工况的位移进行磁定位测量。本文研究了磁定位测井原理,分析了磁定位校电缆、测井过程测量误差的影响因素,确定了系统性误差与随机性误差的组成。制定了封隔器在井下各工况相对于自由悬挂状态的位移的测试方案。该方案抵消了系统误差,将封隔器位移的误差范围控制在±0.15米以内。采用该方案测试了某井五个封隔器在不同工况下的位移。     

The producer welfare effects of trade liberalization when goods are perishable and habit‐forming: the case of asparagus

Asparagus is a perishable, highly seasonal crop. We find that out‐of‐season imports of asparagus caused habit formation that increased demand in the U.S. growing seasons. We find that habit effects offset about 64% of the welfare losses to U.S. asparagus producers from increased Mexican imports under NAFTA and all of the U.S. producer welfare losses from increased Peruvian imports under the Andean Trade Preference Act. We estimate that the U.S. producer welfare losses from NAFTA are less than the annualized value of market loss assistance provided them in the 2008 Farm Bill.     

When Social Infrastructure Deficits Create Displacement Pressures: Inner City Schools and the Suburbanization of Families in Melbourne

Under advanced capitalism, gentrification converges with the post‐Keynesian ‘unhinging' of the state from the project of social reproduction, including its responsibilities for collective consumption (e.g. housing, schools). Gentrification research scrutinizes this convergence through the ongoing assault on social/affordable housing, and yet anaemic housing welfare is not its endpoint. The social contract is further fractured through the ongoing discreditation and dismantling of the full gamut of legacies of the publicly regulated Keynesian inner city, including essential social infrastructure. Focusing on public schools, as an essential site for social reproduction, this article explores how the struggle for the city under neoliberal gentrification may be emerging along additional (non‐housing) vectors. Based on a qualitative study of families' experiences of poor public education provision in central Melbourne (Australia), this article argues that the exclusionary effects of gentrification likely exceed residential encroachment as state subsidization of residents continues to yield to the subsidization of capital. In particular, this article identifies life‐stage specific, infrastructure‐related displacement pressures wrought by a state failure to provide adequate public primary schools in the ‘regeneration' of central Melbourne, and it illustrates how these pressures prompt housing strategies that unevenly divest families of the locational advantages secured in the inner city. Highlighting the role of public school deficits in the reluctant suburbanization of lesser‐resourced families assists in foregrounding state complicity in displacement dynamics and the potential for these to magnify socio‐economic, gendered and socio‐spatial inequalities across the city.