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基于等效平面法的切削仿真方法研究及优化
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作者 陈树梁 徐雷 +1 位作者 任清川 牟宗亮 《组合机床与自动化加工技术》 北大核心 2023年第9期137-140,共4页
基于等效平面的方法使用二维正交切削仿真的结果来代替三维斜角切削仿真的应力场和温度场,以便节省模拟时间和成本。针对等效平面法存在一定的误差的问题,在分析误差产生原因的基础上,在温度场方面对等效平面法进行优化,并将其应用到铣... 基于等效平面的方法使用二维正交切削仿真的结果来代替三维斜角切削仿真的应力场和温度场,以便节省模拟时间和成本。针对等效平面法存在一定的误差的问题,在分析误差产生原因的基础上,在温度场方面对等效平面法进行优化,并将其应用到铣削仿真中。首先,建立了等效平面刀具参数与主截面刀具参数之间的转换模型;同时,也对工件的重要参数,如切削厚度、基体厚度、比热和摩擦系数进行了等效处理;最后,通过建立仿真模型进行对比分析,发现基于优化的等效平面法建立的二维切削模型有效地减小了二维模型与三维模型的仿真结果之间的误差,其中,刀具与工件接触区域的最大温度误差从9.63%降低到了0.29%,工件基体的温度分布也得到了显著改善。因此,优化的等效平面法可以有效地减小仿真误差。 展开更多
关键词 斜角切削 等效平面法 刀具等效参数 等效基体厚度 等效比热
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AC-13沥青混合料细观组分材料强度特性研究 被引量:3
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作者 罗旋 李友云 胡迪 《公路工程》 北大核心 2017年第4期294-298,共5页
为了研究AC—13沥青混合料细观力学性能参数的获取方法及骨料粒径对沥青混合料强度的影响,逐级去除上一级骨料,利用剩余各档集料质量比不变及集料总比表面积与沥青用量之比保持不变的原则设计各级沥青混合料试件。采用MTS对各级沥青混... 为了研究AC—13沥青混合料细观力学性能参数的获取方法及骨料粒径对沥青混合料强度的影响,逐级去除上一级骨料,利用剩余各档集料质量比不变及集料总比表面积与沥青用量之比保持不变的原则设计各级沥青混合料试件。采用MTS对各级沥青混合料试件进行单轴抗压强度实验,揭示了骨料对沥青混合料强度的影响规律,并为细观状态下沥青混合料细观参数的获取提供了方法。 展开更多
关键词 沥青混合料 等效基体 比表面积 抗压强度 MTS
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沥青混合料粗集料抗疲劳性能
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作者 李沛洪 《山东交通学院学报》 CAS 2017年第3期74-80,共7页
为研究AC-13沥青混合料在重复荷载下各挡粗集料的抗疲劳性能,提出反映各挡粗集料特性的沥青混合料等效基体(AC-9.5、AC-4.75、AC-2.36、AC-1.18)概念;通过疲劳过程等效基体的开裂特性,分析各挡集料的抗疲劳能力。建立疲劳过程Miner线性... 为研究AC-13沥青混合料在重复荷载下各挡粗集料的抗疲劳性能,提出反映各挡粗集料特性的沥青混合料等效基体(AC-9.5、AC-4.75、AC-2.36、AC-1.18)概念;通过疲劳过程等效基体的开裂特性,分析各挡集料的抗疲劳能力。建立疲劳过程Miner线性损伤模型,设计不同应力水平的劈裂强度试验和疲劳试验,得出各等效基体劈裂抗拉强度和疲劳寿命。依据损伤模型与疲劳寿命结果,划分沥青混合料及其等效基体不同损伤程度(20%~80%)的疲劳作用次数;定义裂纹贯穿比例,分析不同应力水平等效基体随损伤程度的裂纹贯穿变化规律。结果表明:9.5~13.2 mm集料和4.75~9.5 mm集料对提高AC-13沥青混合料抗疲劳性能的作用大于2.36~4.75 mm和13.2~16 mm集料;通过提高4.75~13.2 mm集料的质量分数可以提高沥青混合料的抗疲劳性能,但提高13.2~16 mm和2.36~4.75 mm集料的质量分数对提高抗疲劳性能作用不明显。 展开更多
关键词 道路工程 沥青混合料 等效基体 集料特性 疲劳开裂性能
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沥青混合料细观粘弹性参数获取方法及蠕变特性研究
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作者 李友云 郑新波 王兰英 《公路交通科技(应用技术版)》 CAS CSCD 2013年第5期51-55,共5页
针对细观状态下分析沥青混合料蠕变及粘弹性能时缺乏细观粘弹性参数的问题,给出了利用质量比与比表面积不变的原则,采用将沥青混合料的矿料及其粘附的沥青逐级去除成型等效沥青混合料试件的方法,并运用不同模型来得到粘弹性参数。把剩... 针对细观状态下分析沥青混合料蠕变及粘弹性能时缺乏细观粘弹性参数的问题,给出了利用质量比与比表面积不变的原则,采用将沥青混合料的矿料及其粘附的沥青逐级去除成型等效沥青混合料试件的方法,并运用不同模型来得到粘弹性参数。把剩余材料设计成等效基体试件并与标准级配AC-13C混合料进行了不同温度、不同应力下的蠕变对比实验。用Burgers模型对实验数据进行了拟合,来获取沥青混合料细观粘弹特性参数并分析了其蠕变特性,结果表明随着材料最大公称粒径的逐渐减小各级等效基体所组成的沥青混合料蠕变变形呈逐步增加的趋势,且粘弹性方程中表征瞬时弹性的弹性参数呈逐步减小的趋势。油砂比越大,瞬时弹性及粘性参数越小。随着试验温度的升高,这类等效基体材料的4个粘弹性参数均有降低,砂浆材料变软,其模量呈现降低趋势。当其他条件保持不变时,仅考虑应力变化,蠕变柔量并不总是随应力增大而增大,蠕变柔量随应力变化而变化的规律不是很突出,这些特性与参数为进一步细观分析沥青混合材料提供了试验参数获取方法和理论依据。 展开更多
关键词 道路工程 细观尺度粘弹性参数 蠕变实验 沥青混合料 等效基体
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Scoring the collective effects of SNPs: association of minor alleles with complex traits in model organisms 被引量:2
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作者 YUAN DeJian ZHU ZuoBin +17 位作者 TAN XiaoHua LIANG Jie ZENG Chen ZHANG JieGen CHEN Jun MA Long DOGAN Ayca BROCKMANN Gudrun GOLDMANN Oliver MEDINA Eva RICE Amanda D. MOYER Richard W. MAN Xian YI Ke LI YanKe LU Qing HUANG YiMin HUANG Shi 《Science China(Life Sciences)》 SCIE CAS 2014年第9期876-888,共13页
It has long been assumed that most parts of a genome and most genetic variations or SNPs are non-functional with regard to reproductive fitness.However,the collective effects of SNPs have yet to be examined by experim... It has long been assumed that most parts of a genome and most genetic variations or SNPs are non-functional with regard to reproductive fitness.However,the collective effects of SNPs have yet to be examined by experimental science.We here developed a novel approach to examine the relationship between traits and the total amount of SNPs in panels of genetic reference populations.We identified the minor alleles(MAs)in each panel and the MA content(MAC)that each inbred strain carried for a set of SNPs with genotypes determined in these panels.MAC was nearly linearly linked to quantitative variations in numerous traits in model organisms,including life span,tumor susceptibility,learning and memory,sensitivity to alcohol and anti-psychotic drugs,and two correlated traits poor reproductive fitness and strong immunity.These results suggest that the collective effects of SNPs are functional and do affect reproductive fitness. 展开更多
关键词 collective effects complex traits minor alleles SNPS recombinant inbred lines minor allele content(MAC)
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Flower-like Bi^0/CeO2-δ plasmonic photocatalysts with enhanced visible-light-induced photocatalytic activity for NO removal 被引量:1
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作者 Junli Nie Jianzhi Gao +4 位作者 Qian Shen Weibin Zhang Fei Rao Mirabbos Hojamberdiev Gangqiang Zhu 《Science China Materials》 SCIE EI CSCD 2020年第11期2272-2280,共9页
Plasmonic bismuth(Bi^0)nanoparticle-decorated flower-like CeO2-δ(Bi^0/CeO2-δ)photocatalysts with abundant oxygen vacancies(OVs)were synthesized via a solvothermal method.The OVs can not only improve the separation o... Plasmonic bismuth(Bi^0)nanoparticle-decorated flower-like CeO2-δ(Bi^0/CeO2-δ)photocatalysts with abundant oxygen vacancies(OVs)were synthesized via a solvothermal method.The OVs can not only improve the separation of electron-hole pairs,but also facilitate the adsorption and activation of gas molecules(NO/O2).In addition,the Bi^0 nanoparticles can enhance the visible light response and prevent the recombination of charge carriers by virtue of the surface plasmon resonance(SPR)effect,achieving an excellent ability for NO elimination and NO2 inhibition under visible light irradiation.Density functional theory(DFT)calculations confirm that the Schottky barrier between Bi^0 and CeO2-δaccompanied with the OVs are pivotal for the migration of photogenerated charge carriers to involve in the photocatalytic NO removal.Trapping experiments and in situ FTIR spectroscopy were conducted to explore the mechanism of the photocatalytic NO removal,suggesting that the photocatalytic NO removal can be significantly enhanced by introducing abundant OVs and the involvement of Bi^0 metal nanoparticles. 展开更多
关键词 cerium oxide bismuth nanoparticles oxygen vacancy surface plasmon resonance Schottky barrier NO removal
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Nanoscopic Tip Sensors Fabricated by Gas Phase Etching of Optical Glass Fibers
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作者 Jorg BIERLICH Jens KOBELKE +3 位作者 David BRAND Konstantin KIRSCH Jan DELLITH Hartmut BARTELT 《Photonic Sensors》 SCIE EI CAS 2012年第4期331-339,共9页
Silica-based fiber tips are used in a variety of spectroscopic, micro- or nano-scopic optical sensor applications and photonic micro-devices. The miniaturization of optical sensor systems and the technical implementat... Silica-based fiber tips are used in a variety of spectroscopic, micro- or nano-scopic optical sensor applications and photonic micro-devices. The miniaturization of optical sensor systems and the technical implementation using optical fibers can provide new sensor designs with improved properties and functionality for new applications. The selective-etching of specifically doped silica fibers is a promising method in order to form complex photonic micro structures at the end or within fibers such as tips and cavities in various shapes useful for the all-fiber sensor and imaging applications. In the present study, we investigated the preparation of geometrically predefined, nanoscaled fiber tips by taking advantage of the dopant concentration profiles of highly doped step-index fibers. For this purpose, a gas phase etching process using hydrofluoric acid (HF) vapor was applied. The shaping of the fiber tips was based on very different etching rates as a result of the doping characteristics of specific optical fibers. Technological studies on the influence of the etching gas atmosphere on the temporal tip shaping and the final geometry were performed using undoped and doped silica fibers. The influence of the doping characteristics was investigated in phosphorus-, germanium-, fluorine- and boron-doped glass fibers. Narrow exposed as well as protected internal fiber tips in various shapes and tip radiuses down to less than 15 nm were achieved and characterized geometrically and topologically. For investigations into surface plasmon resonance effects, the fiber tips were coated with nanometer-sized silver layers by means of vapour deposition and finally subjected to an annealing treatment. 展开更多
关键词 Optical fiber tips NANOPROBES gas phase etching doping tip shaping metal coating
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