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Changing Process and Impact Factors of Ecosystem in Shuangtaizi Estuary Wetland of China 被引量:1
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作者 王永洁 郑冬梅 罗金明 《Journal of Landscape Research》 2011年第5期45-48,51,共5页
By introducing geological and natural conditions of Shuangtaizi Estuary Wetland,a national nature reserve,and borrowing Landsat5 TM wetland data of the year 1987 and 2005,the core area of Shuangtaizi Estuary Wetland i... By introducing geological and natural conditions of Shuangtaizi Estuary Wetland,a national nature reserve,and borrowing Landsat5 TM wetland data of the year 1987 and 2005,the core area of Shuangtaizi Estuary Wetland is studied,areas of its natural water,mudflat,seepweed beach,culture zone,reservoir and swag,reed field,rice field and non-wetland landscape are respectively analyzed,as well as the changes of wetland community,water quality,waterfowl quantity and species.It is found that the study area is suffering from serious fragmentation of wetland,reducing reed yield,degrading water quality,decreasing bird species and amount,which implies that the degraded wetland environment has imposed threats on the survival of some wetland species.Root causes of such a result are analyzed from the perspectives of regional climate changes and human interventions;while regional climate changes include obvious temperature increase and precipitation decrease,human interventions include oil exploration,reclamation of land from the lake,overuse of biotic resources,environment pollution.Due to the interactive influence of these two factors,ecosystem of Shuangtaizi Estuary Wetland has experienced drastic changes,which should be attached sufficient importance by relevant departments so as to enhance its protection and management. 展开更多
关键词 WETLAND ECOSYSTEM CHANGING process impact FACTORS Shuangtaizi ESTUARY WETLAND
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Laser Induced Photoelectron Impact Ionization In Multiphoton Ionization Process
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作者 Li WANG Hai Yang LI +3 位作者 Ji Ling BAI Dong Xu DAI Ju Long SUN Ri Chang LU (State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics,Chinese Academy of Sciences, Dalian,116023) 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第11期0-0,0-0,共4页
Multiply charged ions of Ar and NO were observed in MPI experiment Of NO/Ar with TOF-MS. A delayable pulsed acceleration field wn applied tO investigate the effect of the photoelectrons on the formation of the multi... Multiply charged ions of Ar and NO were observed in MPI experiment Of NO/Ar with TOF-MS. A delayable pulsed acceleration field wn applied tO investigate the effect of the photoelectrons on the formation of the multiply charged ions. The multiply charged ions were suggested to be produced by photoelectron impact ionization, in the region bentween the extractor grid and the repeller plate, step by step, from neutral species and lower charged ions. The 50-60ns of FWHM of the ion peaks implies that the pulse width of the photoelectrons should be shorter considering the broadening effect during the ionization process. 展开更多
关键词 308 REV Laser Induced Photoelectron impact Ionization In Multiphoton Ionization process
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Effects on Sedimentary Processes via Upper Triassic Climate Forcing Caused by Multiple Impacting and Large Igneous Provinces (LIP)-Rifting/Degassing: Jordanian Platform/Arabian Plate and Germanic Basin/Central Europe
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作者 Werner Schneider Elias Salameh 《Open Journal of Geology》 CAS 2023年第2期136-170,共35页
Upper Triassic sedimentary systems of both the Arabian Plate and the Germanic Basin reveal climate- and plate tectonic-forced effects through certain time-intervals experienced by architectural elements, lithofacies t... Upper Triassic sedimentary systems of both the Arabian Plate and the Germanic Basin reveal climate- and plate tectonic-forced effects through certain time-intervals experienced by architectural elements, lithofacies types, unconformities, flash flood deposits, maximum flooding surfaces/sequence boundary (MFS/SB), mineralogy, and isotope anomalies. Further, Moon recession and changes of Earth’s rotation velocity (core/mantle boundary) are associated with multiple impacting and large igneous provinces/Mid Oceanic Ridge Basalt, LIP/MORB-rifting/degassing. While acidification (by degassing, sturz-rain) does influence tectosilicates and carbonates, montmorillonite represents a key mineral as transformation of volcanic/impact glass (Tephra) to be found as co-components in and in certain pelite units as “boundary clay-suspicions” (mixture of eolian paleoloess, pelite, paleosol, and tephra → tuffite). Obviously, unconformities and sequence boundaries of both study areas separate and dislocate interrupted ∂<sup>13</sup>C and <sup>87</sup>Sr/<sup>86</sup>Sr-data groups along the isotope curves. Both Proto-Arctic Ocean rifting/degassing comprising kimberlitic pyroclastic eruptions and Neotethys rifting/degassing as well as multiple impacting played the most important role during the Norian, followed by the incipient Central Atlantic Magmatic Provinces rifting since the Rhaetian. The following associations are encountered and dealt with in this study: Sequence boundaries-∂<sup>13</sup>C, maximum flooding surfaces-(FUCs)-∂<sup>13</sup>C, unconformities-plate motion, tephra-pelite-tuffite-montmorillonite. Norian: maximum flooding surfaces (MFSs)-“paleosol”/boundary clay?-rifting-volcanism, Moon/Earth data change. So the Norian (~221 - 206 Ma) hosts anomalous “amalgamated maximum flooding surfaces (MFSs)”, amalgamated paleosol (Jordanian Platform), multiple impacting (~219 - 214 Ma), the maximum opening of the Proto-Arctic Ocean (PAO) (~230 - 200 Ma), Neo-Tethys (NT)-subvolcanic (sills, dikes) in the NE Dead Sea area prior the Rhaetian, and a significant change of Earth/Moon relation data. The study concludes that rare and extreme events are very strongly shaping the geologic constellations in the Earth System. 展开更多
关键词 Endogenic and impact Drivers Sedimentary Effects Interplay processing Event-Stratigraphy
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基于IMPACT2002+的机械加工过程资源环境影响评价方法研究 被引量:4
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作者 潘媛 张华 +1 位作者 朱硕 鄢威 《现代制造工程》 CSCD 北大核心 2019年第3期17-23,37,共8页
为了科学地反映机械加工过程资源、能源以及环境排放情况,提出一种基于CML2001中间类型方法和Eco-indicator99损害类型方法相结合的IMPACT2002+生命周期影响评价方法。通过对中间环境影响指标和4种环境损害指标进行分析,建立机械加工过... 为了科学地反映机械加工过程资源、能源以及环境排放情况,提出一种基于CML2001中间类型方法和Eco-indicator99损害类型方法相结合的IMPACT2002+生命周期影响评价方法。通过对中间环境影响指标和4种环境损害指标进行分析,建立机械加工过程资源消耗和环境排放数据量化、分析与评价体系以及评价模型;通过中间类型影响和损害类型影响的对比分析,可以更好地反映机械加工过程中资源消耗和环境排放情况以及环境影响与工艺的关系。以某机床厂全数控凸轮轴磨床零件丝杆螺母座的制造工艺过程为例,验证了该评价模型与评价方法的可行性。 展开更多
关键词 机械加工过程 资源环境影响 impact2002+
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降雨诱发国道G326顺层滑坡破坏与运动过程研究
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作者 刘仕洪 宋琨 +2 位作者 郭磊 曹俊 姜波 《三峡大学学报(自然科学版)》 CAS 北大核心 2025年第1期44-49,共6页
贵州省国道G326松桃县甘龙镇石板村田堡组顺层滑坡是2020年强降雨诱发的滑坡灾害.在对滑坡变形破坏特征调查的基础上,分析了强降雨诱发滑坡滑动破坏的成因.采用物质点法(materialpointmethod,MPM)进行了滑坡运动过程的模拟,揭示了滑坡... 贵州省国道G326松桃县甘龙镇石板村田堡组顺层滑坡是2020年强降雨诱发的滑坡灾害.在对滑坡变形破坏特征调查的基础上,分析了强降雨诱发滑坡滑动破坏的成因.采用物质点法(materialpointmethod,MPM)进行了滑坡运动过程的模拟,揭示了滑坡运动的速度和冲击荷载等变化规律.结果表明:国道G326滑坡是受2020年7月8日的强降雨诱发的中型顺层岩质滑坡,在8日4时的小时降雨量为96.2mm后约3h发生整体滑移破坏;物质点法能够较真实地模拟滑坡的运动、堆积过程,模拟的堆积体形态与滑坡破坏调查情况基本一致;滑坡岩土体的最大滑动速度为27m/s,最大滑动动能为1.8×109J(15s左右),最大冲击力为37.98×106kN,位于距滑坡后缘约230m处.该研究对国道G326沿线类似滑坡灾害的风险防控具有参考价值和工程借鉴意义. 展开更多
关键词 降雨滑坡 顺层滑动 运动过程模拟 物质点法 冲击荷载
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Manufacturing Process Oriented Environmental Friendly Assessment with Fuzzy Analytic Hierarchy Process and Fuzzy Technique for Order Preference by Similarity to Ideal Solution 被引量:1
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作者 LI Zhongkai HOU Kunfeng HE Chuntian 《Journal of Donghua University(English Edition)》 EI CAS 2018年第3期202-206,共5页
Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for man... Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for manufacturing process,a multi-criteria decision making( MCDM) model combined with fuzzy analytic hierarchy process( FAHP) and fuzzy technique for order preference by similarity to ideal solution( FTOPSIS) is proposed in this work.The environmental and resource criteria and manufacturing process objects are identified as the first step.Then,the weights of the criteria are calculated by FAHP.Finally,based on experts' evaluation using fuzzy words,the manufacturing process objects are ranked by FTOPSIS.The proposed methodology is applied to a gear shaft manufacturing.The sensitivity analysis and comparisons are implemented to prove its robustness and effectiveness for the ecofriendly assessment for process objects. 展开更多
关键词 multi-criteria decision making(MCDM) fuzzy evaluation environmental impact assessment manufacturing process
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Hydrogeochemical processes of thallium in a rural area of Southwest Guizhou,China
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作者 何立斌 肖唐付 +1 位作者 李航 孙伟 《Chinese Journal Of Geochemistry》 EI CAS 2007年第1期52-57,共6页
The water system in a rural area of Lanmuchang in Southwest Guizhou is facing a risk of thallium (Tl) contamination due to Tl mineralization around the area. The major trace elements and Tl in the water system are stu... The water system in a rural area of Lanmuchang in Southwest Guizhou is facing a risk of thallium (Tl) contamination due to Tl mineralization around the area. The major trace elements and Tl in the water system are studied to understand the hydrogeochemical processes of Tl constrained by Tl mineralization. The results showed that the dispersion pattern of Tl follows a descending order in concentration from mine groundwater (deep groundwater) →stream water→shallow groundwater→background water, reflecting the impact of Tl mineralization on the hydrogeochemical composition. Tl concentrations in stream water in both regimes are remarkably higher (2-30 fold) downstream than up- and mid-streams, probably caused by the unidentified discharge of deep groundwater. Low Tl levels are detected in the current drinking water, however, the highly elevated Tl in stream water and ground water may pose a potential environmental risk through daily washing and agricultural irrigation. This study suggests that human activities, such as agricultural irrigation, could intensify the environmental risk of Tl. 展开更多
关键词 贵州东南部 农村地区 水文地球化学过程 环境影响
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The Development of Intelligent Detector for Train Longitudinal Impact
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作者 TIAN E,MO Yimin,NIU Wei (Department of Mechanical and Electrical Engineering,Wuhan University of Technology, Wuhan 430070,China) 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S1期243-247,共5页
This paper introduces a new kind of train impact detecting system that detect the train impact through detecting the train running acceleration,proposes that uniting the train running acceleration and the change rate ... This paper introduces a new kind of train impact detecting system that detect the train impact through detecting the train running acceleration,proposes that uniting the train running acceleration and the change rate of acceleration to token the train impact. The detector takes the portable computer as platform of data processing,utilizes the database technology to process data,making instrument Pc true,and improving the data processing ability of the instrument. The detector can show the train running acceleration on-line and real-timely,indicating the train impact situation directly,and uses the method that the software and hardware unifies to strengthen the system anti-jamming ability. At present,this detector has been tryout in some locomotive depots,each design function and the performance index conforms to request of the scene; the anti-jamming ability is strong,the monitor precision is reasonable,the detector can carry out the on-line examination to the train impact and monitoring the train running condition. 展开更多
关键词 TRAIN longitudinal impact single CHIP data processing ACCELERATION
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Life cycle inventory analysis of CO_2 and SO_2 emission of imperial smelting process for Pb-Zn smelter 被引量:2
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作者 李启厚 郭学益 +2 位作者 肖松文 黄凯 张多默 《Journal of Central South University of Technology》 EI 2003年第2期108-112,共5页
Based on the principle of life cycle assessment, CO2 and SO2 emission of Imperial Smelting Process in a certain zinc-lead smelter was analyzed by life cycle inventory method. According to the system expansion and subs... Based on the principle of life cycle assessment, CO2 and SO2 emission of Imperial Smelting Process in a certain zinc-lead smelter was analyzed by life cycle inventory method. According to the system expansion and substitution method, the environmental impacts of co-products were allocated among the main products of zinc, lead and sulfuric acid. The related impacts were assessed by use of Global Warming Potential (GWP) and Acidification Potential (ACP). The results show that the GWP index from 1998 to 2000 is 11.53, 11.65, 10.93 tCO2-eq/tZn respectively, the ACP index decreases from 14.88 kgSO2-eq/tZn in 1998 to 10.99 kgSO2-eq/tZn in 2000. Power and electricity generation, followed by smelting and zinc distillation, are mainly responsible for GWP. Sintering individually affects ACP. Reduction in greenhouse gas emissions of the ISP may come from energy conservation measures rather than from technological developments. And recycling more secondary Pb and Zn materials effectively treated by ISP, and reducing the amount of primary metal are the main ways to put SO2 emission under control. 展开更多
关键词 impact assessment life cycle inventory imperial smelting process ZINC LEAD
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考虑极端天气冲击过程的风电机组竞争失效可靠性评估 被引量:1
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作者 赵洪山 林诗雨 +2 位作者 曲岳晗 杨澳 常杰英 《电力自动化设备》 EI CSCD 北大核心 2024年第4期40-47,共8页
针对风电机组的运行可靠性易受极端天气影响的问题,提出了一种考虑极端天气冲击过程的风电机组竞争失效可靠性评估方法。同时考虑风电机组自然退化、极端天气冲击导致的瞬时退化以及极端天气持续过程产生的加速退化,构建极端天气下的风... 针对风电机组的运行可靠性易受极端天气影响的问题,提出了一种考虑极端天气冲击过程的风电机组竞争失效可靠性评估方法。同时考虑风电机组自然退化、极端天气冲击导致的瞬时退化以及极端天气持续过程产生的加速退化,构建极端天气下的风电机组综合退化模型;考虑风电机组退化过程对其耐冲击性能的影响,建立风电机组竞争失效可靠度模型以评估风电机组可靠性;基于我国北方某风电场工程数据和极端天气历史数据评估了某2 MW风电机组的可靠性并进行了参数灵敏度分析。结果显示,到第5年时,仅考虑自然退化的方法评估风电机组可靠度为0.84,而考虑极端天气冲击过程的方法评估风电机组可靠度为0.178,后者更加符合工程实际。通过模型参数的灵敏度分析发现,运行时间超过3年后,退化失效开始逐渐影响风电机组的可靠性。 展开更多
关键词 风电 风电机组可靠性评估 极端天气冲击 冲击持续过程 竞争失效 硬失效阈值退化
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预回火工艺对H13钢组织和性能的影响
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作者 王稳 程晓农 +6 位作者 苗现华 倪聪 贾海涛 刘超杰 蒋沁洋 丁恒楠 罗锐 《机械工程材料》 CAS CSCD 北大核心 2024年第10期47-54,共8页
对淬火后H13钢进行620,640,660,680℃下保温10,20,40min的预回火与600℃保温120min回火处理,并以常规回火(二次600℃保温120min回火)为对照,研究了预回火工艺对H13钢组织和性能的影响。结果表明:随着预回火温度提高或保温时间延长,H13... 对淬火后H13钢进行620,640,660,680℃下保温10,20,40min的预回火与600℃保温120min回火处理,并以常规回火(二次600℃保温120min回火)为对照,研究了预回火工艺对H13钢组织和性能的影响。结果表明:随着预回火温度提高或保温时间延长,H13钢中马氏体分解程度增加,残余奥氏体数量减少,析出碳化物尺寸增大,位错密度降低,H13钢的硬度降低,冲击吸收功增大;与常规回火相比,620,640℃下预回火10~20min+600℃回火后H13钢的位错密度更高,660,680℃下预回火10~40min+600℃回火后H13钢的的位错密度更低,660℃下预回火10~40min+600℃回火处理可以同时提高硬度和冲击韧性,其原因是较低位错密度和较小尺寸回火析出相的共同作用。 展开更多
关键词 H13钢 预回火工艺 马氏体 冲击韧性 碳化物
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混凝土梁尾波信号环境噪声对照补偿法
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作者 郑罡 薛文琪 +1 位作者 宋林正 张智宇 《中国科技论文》 CAS 2024年第9期1011-1017,共7页
为推进超声尾波技术在混凝土结构检测中的应用,研究了环境干扰引起的混凝土梁超声尾波信号特征噪声并提出噪声补偿方法。开展了自然环境下的混凝土梁超声试验,提出平移缩放旋转多特征算法,将尾波信号的波速、频率、幅值特征以时间平移... 为推进超声尾波技术在混凝土结构检测中的应用,研究了环境干扰引起的混凝土梁超声尾波信号特征噪声并提出噪声补偿方法。开展了自然环境下的混凝土梁超声试验,提出平移缩放旋转多特征算法,将尾波信号的波速、频率、幅值特征以时间平移、时轴缩放、向量旋转3种参数形式进行分析。通过两试件超声对照试验,对尾波环境噪声进行补偿,并与尾波干涉法信号降噪结果进行对比,验证本文方法的有效性。结果表明:温度是尾波环境噪声的主要来源,湿度为次要来源;本文方法对尾波信号的降噪效果可达到91%以上,显著优于尾波干涉法;通过对照试件特征参数的噪声补偿可达到90%水平。研究结果可为提高尾波信号稳定性提供研究方法与试验基础。 展开更多
关键词 混凝土 超声尾波 环境影响 信号处理
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Microstructure,mechanical properties,and wear resistance of VCp-reinforced Fe-matrix composites treated by Q&P process 被引量:2
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作者 Ping-hu Chen Yi-bo Li +3 位作者 Rui-qing Li Ri-peng Jiang Song-sheng Zeng Xiao-qian Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第9期1060-1069,共10页
A quenching and partitioning(Q&P) process was applied to vanadium carbide particle(VCp)-reinforced Fe-matrix composites(VC-Fe-MCs) to obtain a multiphase microstructure comprising VC, V8 C7, M3 C, α-Fe, and γ-Fe... A quenching and partitioning(Q&P) process was applied to vanadium carbide particle(VCp)-reinforced Fe-matrix composites(VC-Fe-MCs) to obtain a multiphase microstructure comprising VC, V8 C7, M3 C, α-Fe, and γ-Fe. The effects of the austenitizing temperature and the quenching temperature on the microstructure, mechanical properties, and wear resistance of the VC-Fe-MCs were studied. The results show that the size of the carbide became coarse and that the shape of some particles began to transform from diffused graininess into a chrysanthemum-shaped structure with increasing austenitizing temperature. The microhardness decreased with increasing austenitizing temperature but substantially increased after wear testing compared with the microhardness before wear testing; the microhardness values improved by 20.0% ± 2.5%. Retained austenite enhanced the impact toughness and promoted the transformation-induced plasticity(TRIP) effect to improve wear resistance under certain load conditions. 展开更多
关键词 vanadium CARBIDE Fe-matrix composites QUENCHING and partitioning process transformation-induced plasticity effect MICROHARDNESS impact toughness wear resistance
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航空发动机弯管内表面磁力研磨技术的研究进展
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作者 肖春芳 韩冰 谢臻 《电镀与精饰》 CAS 北大核心 2024年第12期91-100,共10页
航空发动机弯管的内表面质量影响发动机的整体性能和安全。磁粒研磨具有无须专用加工设备、精度高、柔性和仿形性好、易于实现自动化等优势,有望成为航空发动机弯管内表面精密加工的主要技术途径。介绍了磁粒研磨的方法和机理,总结了聚... 航空发动机弯管的内表面质量影响发动机的整体性能和安全。磁粒研磨具有无须专用加工设备、精度高、柔性和仿形性好、易于实现自动化等优势,有望成为航空发动机弯管内表面精密加工的主要技术途径。介绍了磁粒研磨的方法和机理,总结了聚磁装置对磁粒研磨的影响,各因素及交互作用因素对表面粗糙度和材料去除的影响。提出了基于开槽磁极的离散法提高磁粒研磨精度和效率和基于遗传算法优化的BP神经网络预测最佳航空发动机弯管磁粒研磨工艺参数的优化思路,并归纳了磁粒研磨效果评价方法。列举了磁粒研磨技术在航空发动机弯管内表面精密加工中的应用,并对航空发动机弯管内表面磁力研磨技术的发展趋势进行了展望。 展开更多
关键词 航空发动机弯管 磁粒研磨机理 工艺参数 效果评价 发展趋势
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对冲式冲击试验机的设计及其动力特性的研究
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作者 胡俊宏 尹远博 +1 位作者 吴畅 张福同 《机电工程》 CAS 北大核心 2024年第11期2098-2105,共8页
为了对舰船内部电子设备进行高加速度冲击检测,提高冲击试验机的检测能力,对传统的冲击试验机进行了结构上的改进,提出了一种新型的对冲式冲击试验机,并对设计参数及其动力特性进行了研究。首先,介绍了对冲式冲击试验机的机械结构和控... 为了对舰船内部电子设备进行高加速度冲击检测,提高冲击试验机的检测能力,对传统的冲击试验机进行了结构上的改进,提出了一种新型的对冲式冲击试验机,并对设计参数及其动力特性进行了研究。首先,介绍了对冲式冲击试验机的机械结构和控制原理,建立了设备的运动学模型,将试验动作划分成了四个过程(分别为蓄能、释放、碰撞与刹车阶段),并对各阶段进行了数学建模分析,确定了最大能量碰撞点;然后,建立了实体模型,使用ANSYS软件对其进行了计算机仿真,评估了结构稳定性,预测了其冲击加速度;最后,通过多次试验检测了动力特性,在不同位置下重复测试了该设备碰撞点位置与产生的冲击加速度大小,采集了加速度与位移信号,对信号进行了降噪滤波处理与微分计算,验证了设备性能的可靠性。研究结果表明:该试验机结构简单、操作容易,可重复试验;每次试验中碰撞点距理想位置分布数据散度在30 mm以内,数据稳定可靠,符合设计需求,控制方法合理;通过调节试验台与冲击台的释放位置可以改变冲击产生的加速度大小,在极限位置释放时最高能产生2 000 g左右的冲击加速度,满足各种元器件对耐冲击测试的试验要求。 展开更多
关键词 冲击试验机 冲击试验 可靠性 运动学模型 运动过程分析 ANSYS 结构稳定性 冲击加速度
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飞机碳纤维复合材料蒙皮激光除漆技术的研究进展
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作者 肖春芳 邵林发 《光学技术》 CAS CSCD 北大核心 2024年第2期150-159,共10页
碳纤维复合材料是飞机蒙皮的重要材料,除漆是飞机碳纤维复合材料蒙皮再次涂装之前最为重要的工序。激光除漆具有高效、可控、分层、“绿色”的优势,有望成为飞机碳纤维复合材料蒙皮除漆的主要技术途径。介绍了激光分层可控除漆方法和机... 碳纤维复合材料是飞机蒙皮的重要材料,除漆是飞机碳纤维复合材料蒙皮再次涂装之前最为重要的工序。激光除漆具有高效、可控、分层、“绿色”的优势,有望成为飞机碳纤维复合材料蒙皮除漆的主要技术途径。介绍了激光分层可控除漆方法和机理,总结了激光能量密度、激光扫描速度、激光搭接率等工艺因素对飞机碳纤维复合材料蒙皮涂层去除的影响规律,提出了激光分层可控除漆工艺的优化思路,并归纳了激光除漆效果评价方法。列举了激光除漆技术在飞机复合材料表面涂层维修中的应用,并对飞机碳纤维复合材料蒙皮激光除漆技术的发展趋势进行了展望。 展开更多
关键词 飞机碳纤维复合材料蒙皮 激光除漆机理 工艺参数 效果评价 发展趋势
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某迫榴炮击针疲劳寿命仿真与提升研究
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作者 宁变芳 王涛 +2 位作者 韩璇璇 崔青春 张凡凡 《火炮发射与控制学报》 北大核心 2024年第3期87-92,共6页
击针大多采用细长及变截面结构,在循环撞击力作用下,易引起结构应力集中及交变应力,经常出现疲劳断裂故障,严重影响自动武器的可靠性,甚至威胁到作战人员安全。某迫榴炮击针在试验中偶发断裂现象,疲劳寿命约200发左右,为了提升该击针疲... 击针大多采用细长及变截面结构,在循环撞击力作用下,易引起结构应力集中及交变应力,经常出现疲劳断裂故障,严重影响自动武器的可靠性,甚至威胁到作战人员安全。某迫榴炮击针在试验中偶发断裂现象,疲劳寿命约200发左右,为了提升该击针疲劳寿命,基于载荷传递过程,建立了击针在火药气体反冲力下高速运动与限位块的瞬态撞击模型,获取击针撞击过程交变应力,通过循环载荷作用下击针疲劳寿命评估,计算击针疲劳寿命与试验现象基本一致,验证了计算模型的准确性。在此基础上,开展了不同材料击针疲劳寿命提升研究,研究表明,将击针材料由PCrNi3Mo更换为30CrNi2MoVE后,击针疲劳寿命由215发提升到1670发,提升效果显著,改进后的击针经实弹射击试验验证在规定寿命周期内未发生断裂现象。 展开更多
关键词 迫榴炮 发射过程 载荷传递 瞬态撞击 循环载荷 疲劳寿命
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浇注温度与型壳温度对K4648镍基高温合金组织和性能的影响
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作者 张丽辉 高达 +5 位作者 黄强 张楚博 张强 任晓冬 胡聘聘 张勇 《机械工程材料》 CAS CSCD 北大核心 2024年第6期75-80,共6页
针对某型号燃气涡轮导向器用K4648镍基高温合金室温冲击韧性无法达到标准要求(冲击韧性大于20 J·cm^(-2))的问题,在不同的浇注温度与型壳温度(1 490℃/1 050℃,1 490℃/950℃,1 460℃/1 050℃)下制备了K4648镍基高温合金,并进行了... 针对某型号燃气涡轮导向器用K4648镍基高温合金室温冲击韧性无法达到标准要求(冲击韧性大于20 J·cm^(-2))的问题,在不同的浇注温度与型壳温度(1 490℃/1 050℃,1 490℃/950℃,1 460℃/1 050℃)下制备了K4648镍基高温合金,并进行了固溶+标准热处理,研究了浇注温度与型壳温度对合金显微组织和冲击性能的影响,获得了优化的工艺参数。结果表明:当型壳温度或浇注温度较低时,K4648镍基高温合金的晶粒尺寸和二次枝晶间距较小,块状初生α-Cr相含量较少、尺寸较小,合金的冲击韧性较大,冲击断口处次生裂纹数量较少;优化工艺参数为型壳温度950℃、浇注温度1 490℃,此工艺参数下制备的K4648镍基高温合金的冲击韧性最大,为21.4 J·cm^(-2),满足标准要求。 展开更多
关键词 K4648镍基高温合金 浇注工艺 Α-CR相 冲击韧性
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复合材料层压板冲击后压缩全过程仿真分析
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作者 刘湘云 张赢 +3 位作者 李晓龙 朱梦杰 赵征 李梦佳 《航空计算技术》 2024年第4期106-109,共4页
针对复合材料层压板低速冲击数值模拟中将冲击和压缩过程割裂计算的问题,建立了将冲击和压缩两个过程统为一体的数值模拟方法。分别采用显式分析和隐式分析模拟冲击和压缩过程,将层压板冲击后的损伤数据、应力应变数据、位移数据等作为... 针对复合材料层压板低速冲击数值模拟中将冲击和压缩过程割裂计算的问题,建立了将冲击和压缩两个过程统为一体的数值模拟方法。分别采用显式分析和隐式分析模拟冲击和压缩过程,将层压板冲击后的损伤数据、应力应变数据、位移数据等作为下一步的初始输入进行压缩模拟,并采用三维Hashin失效判据来判断复合材料的初始破坏,并对破坏后的复合材料进行刚度折减,来模拟损伤演化。采用试验标准建立有限元模型对所建立的数值模拟方法进行验证,计算结果与试验对比表明:失效模式一致,剩余强度相对误差满足工程要求。 展开更多
关键词 复合材料 冲击后压缩 剩余强度 失效准则 全过程仿真
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基于台风过程的低矮建筑围护结构易损性分析
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作者 黄鹏 周华亮 蓝鑫玥 《振动与冲击》 EI CSCD 北大核心 2024年第22期1-9,共9页
我国沿海台风多发地区的低矮建筑围护结构风灾损失值得关注。基于台风过程研究了低矮建筑围护结构在风致内外压、飞掷物冲击、结构抗力等多因素影响下的易损性。针对典型低矮建筑场景建立了飞掷物冲击概率模型,可以有效考虑风向、风速... 我国沿海台风多发地区的低矮建筑围护结构风灾损失值得关注。基于台风过程研究了低矮建筑围护结构在风致内外压、飞掷物冲击、结构抗力等多因素影响下的易损性。针对典型低矮建筑场景建立了飞掷物冲击概率模型,可以有效考虑风向、风速、建筑高度和间距,以及飞掷物起飞位置等实际因素。研究结果表明:低矮建筑围护结构的台风风灾易损性分析中有必要考虑台风过程,极值风速相似的台风也可能造成较大差别的建筑损伤极值;建筑损伤极值发生时刻一般滞后于极值风速时刻,损伤极值的持续时间与台风时长有关。研究中建立的飞掷物冲击概率模型相较于传统模型对我国沿海地区典型低矮建筑场景更为适用。 展开更多
关键词 风灾易损性 台风过程 低矮建筑 飞掷物冲击
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