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爆破振动信号承载了丰富的爆源与地质属性特征信息,为从能量分布与能量密度角度解析爆破振动信号时频特征,并准确识别毫秒延时爆破实际段间延时时间。设计开展工程现场精确延时台阶爆破振动监测试验,通过MATLAB软件编制小波变换与小波包分析程序,研究爆破振动信号能量在频域的分布规律,利用时能密度分析方法对毫秒延时爆破实际延时时间进行识别。研究结果表明,精确延时台阶爆破振动能量主要集中于5~150 Hz频带范围,并可划分为多个能量集中的子振频带。峰值振动速度与振动能量随传播距离逐渐衰减,但衰减速率存在差异。依据振动信号时间能量密度分布曲线可有效确定实际延时时间,识别延时时间与设计延时时间最大相对误差为4.2%,平均相对误差为2%。提出了一种考虑地震波传播距离差异因素的延时识别修正方法,弥补了各炮孔与监测点距离变化引起地震波传导时间增减而导致的延时识别误差。研究成果可为毫秒延时爆破参数优化设计及电子雷管起爆网路盲炮识别提供理论依据,为复杂环境爆破振动效应分析及控制积累经验。 相似文献
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为从能量分布角度研究爆破振动信号以控制爆破地震危害,利用小波包技术对比分析了单段和多段微差爆破、单段有无临空面等不同爆破条件下监测到的爆破振动信号各频带上的能量分布特性,研究结果表明:爆破振动信号能量集中分布在200 Hz以下的主振频带附近,主振频带又可分为几个子振带;爆破振动信号中高频(90~125 Hz)成分的衰减快于低频(0~75 Hz)成分;单段爆破条件下振动信号在低频带上的能量分布要高于多段微差爆破时振动信号在该频带上的能量分布;当炮孔有临空面时,炸药爆炸后穿过岩石粉碎区并以地震波形式传播的能量会减小;单段爆破时,药量的增加会导致振动信号总能量的明显增加,但对于各频带能量分布规律的影响并不明显。 相似文献
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坝基开挖爆破振动频带小波能量分析 总被引:5,自引:2,他引:3
结合蒲石河蓄能电站下水库坝基开挖爆破振动监测数据,运用小波分析方法,对爆破振动信号进行小波多层分解,获得各频带PPV及爆破振动分量的小波频带能量,通过分析比较,得出此次爆破振动信号的能量在频域上分布较广泛,但绝大部分能量集中在0~200 Hz,在传播过程中能量迅速衰减;小波频带能量可以反映爆破振动信号强度、频率和作用时间;并指出爆破振动出现的多子频、多峰值揭示了只采用单个主振频带来代替整个频域,有欠准确,在未来的研究中应将多主频的影响因素考虑进去. 相似文献
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为探索岩体结构面对爆破振动速度峰值、主频和信号中的能量分布等的影响,在钻沟石灰石露天矿爆破生产现场进行爆破振动测试。分别采用小波包分析和ANSYS/LS-DYNA数值模拟软件对结构面影响下的爆破振动信号和爆破振动传播规律进行分析研究。小波包分析结果表明,当地震波穿过结构面时,爆破振动频率介于0~15.6 Hz之间的能量占爆破地震波能量比例随之增加,增幅达63.1%,而振动频率介于15.7~31.3 Hz之间的能量比例随之降低,降幅达56.9%。数值模拟结果表明,爆破地震波在未穿过结构面之前和穿过结构面后,振速峰值没有明显的衰减;而穿过结构面时,振速峰值衰减明显,其平均减震率为40.66%。此外,地震波在坡体内受高程和结构面双重作用,导致其放大系数呈先增大后减小的趋势。 相似文献
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单段爆破振动信号频带能量分布特征的小波包分析 总被引:3,自引:3,他引:3
爆破振动分析是研究爆破振动危害控制的基础,也是控制爆破振动危害的前提。根据爆破振动信号具有短时非平稳的特点,利用小波包分析技术对满足分析要求的单段微差爆破振动信号的能量分布特征进行研究。首先,简略地介绍了小波变换与小波包分析的特点。其次,基于MATLAB对单段爆破振动信号进行小波包分析,得到了爆破振动信号在不同频带上的能量分布图。最后,总结了单段爆破振动信号频带能量的分布特征。结果表明,在单段爆破中,爆破震动信号成分主要以中高频(39Hz~156Hz)为主,低频成分(39Hz以下)所占比例极少。 相似文献
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为了研究液态CO_2爆破系统地震波时频特性,现场微震监测试验获得液态CO_2爆破地震波信号,根据爆破地震波信号具有非平稳的特点,首先采用自适应最优核时频分析方法对地震波信号的基本时频特征进行研究,在此基础上通过结合小波包变换分解与重构技术和自适应最优核时频分析方法,对地震波信号的能量分布进行了精细化分析。结果表明:液态CO_2爆破地震波的衰减速度较快,震动速度处于很低的水平;主频范围在30~70 Hz之间,持续时间约为20~30 ms;能量主要分布在0~125 Hz,由两个两个主要区域组成,表明在液态CO_2爆破作用过程中高压流体产生两次不同峰值压力的爆炸冲击波。 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
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On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
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《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献