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基于作用线增量法摆杆活齿传动误差分析
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作者 宜亚丽 郭辉 +1 位作者 卫锐 金贺荣 《制造技术与机床》 北大核心 2018年第8期64-70,共7页
针对活齿传动共轭啮合导致传动误差影响因素复杂的情况,以二齿差摆杆活齿传动机构为研究对象,采用速度瞬心法,推导各啮合副瞬时传动比,运用作用线增量法分别得到摆杆活齿与激波器和中心轮的传动误差,结合多齿啮合传动特性,最终构建二齿... 针对活齿传动共轭啮合导致传动误差影响因素复杂的情况,以二齿差摆杆活齿传动机构为研究对象,采用速度瞬心法,推导各啮合副瞬时传动比,运用作用线增量法分别得到摆杆活齿与激波器和中心轮的传动误差,结合多齿啮合传动特性,最终构建二齿差摆杆活齿传动误差模型。通过统计分析和实例计算,结果表明,中心轮误差对传动误差的影响最大,摆杆活齿误差的影响次之,激波器误差的影响最小,该研究方法能直观地获得活齿传动机构传动误差的分布情况,提出的精度设计方案能够满足装备传动技术需求。 展开更多
关键词 活齿传动机构 作用线增量 多齿啮合 蒙特卡洛模拟 精度设计
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作用线增量法及其应用 被引量:1
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作者 桂定一 《湖北汽车工业学院学报》 2005年第1期16-19,共4页
介绍了作用线增量法的含义及其应用场合;用实例说明了作用线增量法分析系统的建立和分析过程;提出了一个重要的分析工具———增量三角形;用齿轮几何偏心与啮合线增量关系的分析实例说明了作用线增量法的应用。
关键词 作用线增量 增量三角形 齿轮误差分析
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增量荷载作用下深部煤巷冲击破坏规律模拟试验研究 被引量:5
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作者 孔令海 《煤炭学报》 EI CAS CSCD 北大核心 2021年第6期1847-1854,共8页
为研究深部煤巷道围岩应力状态与围岩结构冲击破坏之间的关系,探索深部煤巷冲击地压发生机制,利用设计的可水平和垂直双向增量加载相似模拟试验平台,试验分析了巷道围岩全过程(自掘进至成巷)应力演化及宏观破坏特征,研究了增量荷载作用... 为研究深部煤巷道围岩应力状态与围岩结构冲击破坏之间的关系,探索深部煤巷冲击地压发生机制,利用设计的可水平和垂直双向增量加载相似模拟试验平台,试验分析了巷道围岩全过程(自掘进至成巷)应力演化及宏观破坏特征,研究了增量荷载作用深部煤巷围岩冲击破坏规律。研究得到:(1)掘进成巷时,巷道围岩体为应力卸荷状态;成巷后,巷道围岩应力开始进入"缓增—快增—缓增"波动阶段;当巷道模型左侧和顶部载荷增加时,围岩变形增大、局部破坏明显,巷道围岩应力开始进入"快增—突变"阶段,巷道发生冲击破坏;冲击破坏后,巷道围岩应力进入"降低—稳定"阶段,与载荷增加前的围岩应力大小相比,顶底板岩层、左帮、右帮浅部等煤体应力基本恢复到冲击破坏前的大小,但巷道右帮煤体深部应力仍处于较高应力状态。(2)深部煤巷围岩冲击破坏与其应力状态呈正相关关系,静载作用下围岩应力呈波动缓增状态,围岩结构破坏不明显;增量荷载作用下,巷道围岩应力呈快增突变状态,局部围岩破坏明显、冲击破坏发生,围岩应力经历了从初始增加到波动增加、再到突变及平衡共7个演化阶段,试验再现了围岩冲击破坏发生的全过程,揭示了冲击破坏发生时的围岩应力突变特征。(3)在山东滕东煤矿3_(下)113综放工作面开展了工程实践研究,现场实测表明,试验结果基本符合现场实际,验证了本文试验方法及结果的可靠性。基于试验结果,提出优化调整巷道围岩应力时空变化和提高围岩整体性的围岩卸压与补强支护技术方案,为深部煤巷冲击地压防治提供了重要依据。 展开更多
关键词 深部煤巷 冲击地压 围岩破坏全过程 相似模拟试验 增量荷载作用
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驻韩美军基地整合及其动向效应
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作者 郭锐 徐文吉 《同济大学学报(社会科学版)》 2004年第5期29-34,共6页
适逢朝核危机白热化之际 ,美国提出对驻韩美军基地进行重新整合 ,必然有其深刻意含。整合拟分两阶段进行。整合后的驻韩美军不仅将具备更强大的震慑力量和更快速的反应能力 ,亦将成为美国构建全球范围下国家安全战略网络的先驱部队。重... 适逢朝核危机白热化之际 ,美国提出对驻韩美军基地进行重新整合 ,必然有其深刻意含。整合拟分两阶段进行。整合后的驻韩美军不仅将具备更强大的震慑力量和更快速的反应能力 ,亦将成为美国构建全球范围下国家安全战略网络的先驱部队。重新部署驻韩美军是美国早已确定的全球范围下驻军调整行动的一部分 ,但此举无疑将加深朝鲜半岛南北双方的忧虑。这对本已危机重重的半岛问题而言 ,无疑又楔入了一个危险参数 。 展开更多
关键词 驻韩美军 基地整合 增量作用 动向效应
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Removal of Nickel(II) from Aqueous Solution Using Activated Charcoal Derived from the Leaves of Bitter Orange Tree (Citrus aurantium)
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作者 Areej. A. Jarullah Karim. H. Hassan Mahasin. F. Ahas 《Journal of Chemistry and Chemical Engineering》 2012年第11期1003-1009,共7页
The present work deals with the removal of Ni(II) ion using activated charcoal prepared from the dry leaves of bitter orange tree (Citrus aurantium). The effects of its concentration, adsorbent dosage, particle si... The present work deals with the removal of Ni(II) ion using activated charcoal prepared from the dry leaves of bitter orange tree (Citrus aurantium). The effects of its concentration, adsorbent dosage, particle size, pH and temperature on removal of Ni(II) ion have been studied. The removal of Ni(II) ion is higher at lower concentration and gradually decreases as the concentration increases. The pH of 5 was the most suitable. The removal of Ni(II) ion increases with the increases in the adsorbent dosage. The effect of particle size reveals that the percentage removal of Ni(II) ion decreases with increase in particle size of adsorbent. The effect of temperature shows that as temperature increases, the percentage removal of Ni(II) ion decreases and this is due to the interaction forces weakening at high temperature. Thermodynamic parameters from the effect of temperature were calculated. 展开更多
关键词 Leaves of bitter orange tree activated carbon nickel ion thermodynamic parameters.
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INHIBITORY EFFECT OF FLUVASTATIN ON AORTIC INTIMAL THICKENING IN NORMOCHOLESTEROLEMIC RABBITS 被引量:1
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作者 叶平 于岱承 +2 位作者 宋立功 邓新心 赵亚力 《Chinese Medical Sciences Journal》 CAS CSCD 2000年第3期140-144,共5页
The anti atherosclerotic effect of fluvastatin at doses insufficient to lower serum cholesterol on the catheter induced intimal thickening and possible mechanism were investigated in abdominal aorta of rabbits. Method... The anti atherosclerotic effect of fluvastatin at doses insufficient to lower serum cholesterol on the catheter induced intimal thickening and possible mechanism were investigated in abdominal aorta of rabbits. Methods.Fifty six rabbits were randomly divided into eight groups(n=7,each).Fluvastatin was given mixed with food at daily dose of8mg/kg starting 5 days before catheterization.Light microscope,immunohistochemistry,transmission electron microscope and RT PCR assay were applied to assess vascular smooth muscle cell (VSMC)proliferation and apoptosis, as well as oncogene expression in vascular wall. Results.At day 10 and day 15 after catheter induced denudation intima/media(I/M)thickness ratio was obviously higher, and also the percentage of PCNA positive cells and TUNEL positive cells in media was significantly higher compared with controls.The intimal hyperplasia was mostly composed of α SM actin positive cells.In rabbits given fluvastatin I/M ratio and the percentage of these positive cells significantly decreased compared with those without fluvastatin.The overexpression of proto oncogene H ras mRNA and decreased expression of anti oncogene p53 mRNA were found after vascular injury,whereas fluvastatin significantly reduced H ras mRNA and increased p53 mRNA expression. Conclusion.Proliferation of VSMC in the media and the migration to the intima can be inhibited,and apoptosis of VSMC be induced by short term use of fluvastatin after balloon catheter denudation,independent of serum lipid change.The underlying mechanism is presumably associated with the influence of fluvastatin on oncogene expression in the injured vascular wall. 展开更多
关键词 HMG CoA reductase inhibitor smooth muscle cells apoptosis
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Entanglement of a Five-Qubit Heisenberg XX Chain in a Magnetic Field
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作者 CAO Min LING Yin-Sheng ZHU Shi-Qun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第5期811-814,共4页
We calculate the eigenvalues and eigenvectors of a five-qubit isotropic Heisenberg model in an external magnetic field, and give analytical results for the concurrence of two nearest-neighbor qubits. A magnetic field ... We calculate the eigenvalues and eigenvectors of a five-qubit isotropic Heisenberg model in an external magnetic field, and give analytical results for the concurrence of two nearest-neighbor qubits. A magnetic field can eliminate degeneration and change the ground state of the system. Therefore increasing the value of the magnetic field can induce entanglement in a certain range both for the antiferromagnetic and ferromagnetic case. 展开更多
关键词 ENTANGLEMENT five-qubit Heisenberg chain
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Synergistic Effects of Biochar and NPK Fertilizer on Soybean Yield in an Alkaline Soil 被引量:8
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作者 Fatima Z.METE Shamim MIA +2 位作者 Feike A.DIJKSTRA Md.ABUYUSUF A.S.M.Iqbal HOSSAIN 《Pedosphere》 SCIE CAS CSCD 2015年第5期713-719,共7页
Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial expe... Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil. 展开更多
关键词 biological nitrogen fixation biomass production P availability seed yield soil pH
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What makes the Tc of monolayer FeSe on SrTiO3 so high: a sign-problem-free quantum Monte Carlo study 被引量:4
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作者 Zi-Xiang Li Fa Wang +1 位作者 Hong Yao Dung-Hai Lee 《Science Bulletin》 SCIE EI CAS CSCD 2016年第12期925-930,共6页
Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based... Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based superconductors. Angle-resolved photoemission spectroscopy observed ‘‘replica bands' ' suggesting the importance of the interaction between FeSe electrons and STO phonons. These facts rejuvenated the quest for T_c enhancement mechanisms in iron-based, especially ironchalcogenide, superconductors. Here, we perform the first numerically-exact sign-problem-free quantum Monte Carlo simulations to iron-based superconductors. We(1) study the electronic pairing mechanism intrinsic to heavily electron doped FeSe films, and(2) examine the effects of electron–phonon interaction between FeSe and STO as well as nematic fluctuations on T_c. Armed with these results, we return to the question ‘‘what makes the Tcof monolayer FeSe on SrTiO_3 so high?'' in the conclusion and discussions. 展开更多
关键词 High temperature superconductivity Pairing mechanism Iron-based superconductivity FeSe/STO Sign-problem-free quantum Monte-Carlosimulation
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