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Temperature field evolution and heat transfer during continual local induction cladding 被引量:3
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作者 LIU Si-yu QIN Xun-peng +1 位作者 ZHANG Jin-peng ZHAN Jun 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第5期1572-1586,共15页
The evolution of temperature field of the continual motion induction cladding and the depth of heat affected zone are studied in this study.A three-dimensional finite element model for the point type continual inducti... The evolution of temperature field of the continual motion induction cladding and the depth of heat affected zone are studied in this study.A three-dimensional finite element model for the point type continual induction cladding is established to investigate temperature distributions of fixed and motion induction cladding modes.The novel inductor is designed for cladding of curved surfaces.The modeling reliability is verified by the temperature measurements.The influence of process parameters on the maximum temperature and the generation and transfer of heat are studied.Quantitative calculation is performed to its melting rate to verify the temperature distribution and microstructures.The results show that a good metallurgical bond can be formed between the cladding layer and substrate.The melting rate gradually falls from the top of the cladding layer to the substrate,and the grain size in the substrate gradually rises.The heat affected zone is relatively small compared to integral heating. 展开更多
关键词 profile repair induction cladding continual motion temperature field evolution heat transfer
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Numerical analysis of 3D spot continual induction hardening on curved surface of AISI 1045 steel 被引量:1
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作者 高恺 汪舟 +1 位作者 秦训鹏 朱生霄 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1152-1162,共11页
In order to investigate and predict the material properties of curved surface AISI 1045 steel component during spot continual induction hardening(SCIH),a 3D model for curved surface workpieces which coupled electromag... In order to investigate and predict the material properties of curved surface AISI 1045 steel component during spot continual induction hardening(SCIH),a 3D model for curved surface workpieces which coupled electromagnetic,temperature and phase transformation fields was built by finite element software ANSYS.A small size inductor and magnetizer were used in this model,which can move along the top surface of workpiece flexibly.The effect of inductor moving velocity and workpiece radius on temperature field was analyzed and the heating delay phenomenon was found through comparing the simulated results.The temperature field results indicate that the heating delay phenomenon is more obvious under high inductor moving velocity condition.This trend becomes more obvious if the workpiece radius becomes larger.The predictions of microstructure and micro-hardness distribution were also carried out via this model.The predicted results show that the inductor moving velocity is the dominated factor for the distribution of 100% martensite region and phase transformation region.The influencing factor of workpiece radius on 100% martensite region and phase transformation region distribution is obvious under relatively high inductor moving velocity but inconspicuous under relatively low inductor moving velocity. 展开更多
关键词 spot continual induction hardening curved surface heating delay phenomenon
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Illuminating the microscopic mysteries of enamel demineralization through terahertz near-field imaging
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作者 XIAO Feng ZHANG Xiao-Qiu-Yan +6 位作者 CHENG Li XU Xing-Xing ZHANG Tian-Yu TANG Fu HU Tao HU Min LIU Sheng-Gang 《红外与毫米波学报》 北大核心 2025年第5期720-725,共6页
Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especial... Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especially continuous wave(CW)THz near-field scanning microscopy(THz-SNOM)with its nanoscale reso⁃lution,can be promising in biomedical imaging.In addition,compared with traditional THz time-domain spec⁃troscopy(TDS),portable solid-state source as the emission has higher power and SNR,lower cost,and can ob⁃tain more precise imaging.In this study,we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale.We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens,mainly due to the decrease in permittivity.This new approach offers valuable insights into the micro⁃scopic processes of enamel demineralization,laying the foundation for further research and treatment. 展开更多
关键词 demineralized enamel near-field scanning microscopy continuous wave TERAHERTZ
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On the Relative Growth Rate of the Digits in Sylvester Continued Fraction Expansions
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作者 LV Meiying RAO Guilin 《应用数学》 北大核心 2025年第2期468-476,共9页
For the Sylvester continued fraction expansions of real numbers,FAN et al.(2007)proved that,for almost all real numbers,the nth partial quotient grows exponentially with respect to the product of the first n-1 partial... For the Sylvester continued fraction expansions of real numbers,FAN et al.(2007)proved that,for almost all real numbers,the nth partial quotient grows exponentially with respect to the product of the first n-1 partial quotients.In this paper,we establish the Hausdorff dimension of the exceptional set where the growth rate is a general function. 展开更多
关键词 Sylvester continued fraction expansions Growth rate Hausdorff dimension
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Continuous-flow columns packed with zero-valent iron and iron sulfide as a feasible strategy to remediate the persistent contaminant nitroguanidine
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作者 Youngjae Yu Erika E.Rios-Valenciana +3 位作者 Robert A.Root Reyes Sierra-Alvarez Jon Chorover Jim A.Field 《Defence Technology(防务技术)》 2025年第1期26-34,共9页
The insensitive munitions compound nitroguanidine(NQ)is used by the U.S.Army to avoid unintended explosions.However,NQ also represents an emerging contaminant whose environmental emissions can cause toxicity toward aq... The insensitive munitions compound nitroguanidine(NQ)is used by the U.S.Army to avoid unintended explosions.However,NQ also represents an emerging contaminant whose environmental emissions can cause toxicity toward aquatic organisms,indicating the need for effective remediation strategies.Thus,we investigated the feasibility of treating water contaminated with NQ in continuous-flow columns packed with zero-valent iron(ZVI)or iron sulfide(FeS).Initially,the impact of pH on NQ transformation by ZVI or FeS was evaluated in batch experiments.The pseudo first-order rate constant for NQ transformation(k_(1,NQ))by ZVI was 8-10 times higher at pH 3.0 compared to pH 5.5 and 7.0,whereas similar k_(1,NQ)values were obtained for FeS at pH 5.5-10.0.Based on these findings,the influent p H fed to the ZVIand Fe S-packed columns was adjusted to 3.0 and 5.5,respectively.Both reactors transformed NQ into nitrosoguanidine(Nso Q).Further transformation of Nso Q by ZVI produced aminoguanidine,guanidine,and cyanamide,whereas Nso Q transformation by Fe S produced guanidine,ammonium,and traces of urea.ZVI outperformed Fe S as a reactive material to remove NQ.The ZVI-packed column effectively removed NQ below detection even after 45 d of operation(490 pore volumes,PV).In contrast,NQ breakthrough(removal efficiency<85%)was observed after 18 d(180 PV)in the Fe S-packed column.The high NQ removal efficiency and long service life of the ZVI-packed column(>490 PV)suggest that the technology is a promising approach for NQ treatment in packed-bed reactors and in situ remediation. 展开更多
关键词 Continuous water treatment Iron-based minerals Chemical reduction pH AMINOGUANIDINE GUANIDINE
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Impact attenuation mechanism of single/double-layer potting structures of MEMS devices under continuous double-pulse impact
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作者 Hao'nan Guo Yunbo Shi +4 位作者 Rui Zhao Yu'nan Chen Peng Zhang Liang Chen Tao Guo 《Defence Technology(防务技术)》 2025年第6期104-114,共11页
High-overload shocks are very likely to cause damage to the microstructure of MEMS devices, especially the continuous multiple high-overload shocks generated by the penetration of the multilayer target environment pos... High-overload shocks are very likely to cause damage to the microstructure of MEMS devices, especially the continuous multiple high-overload shocks generated by the penetration of the multilayer target environment pose more stringent challenges to its protective structure. In this study, the kinetic response model of the protective structure under single-pulse and continuous double-pulse impact is established,and a continuous double-pulse high overload impact test impact platform based on the sleeve-type bullet is constructed, and the protective performance of the multi-layer structure under multi-pulse is analyzed based on the acceleration decay ratio, and the results show that the protective performance of the structure has a positive correlation with its thickness, and it is not sensitive to the change of the load of the first impact;the first impact under double-pulse impact will cause damage to the microstructure through the superposition of the second impact. The first impact under double-pulse impact will cause an increase in the overload amplitude of the second impact through superposition;compared with the single-layer structure, the acceleration attenuation ratio of the double-layer structure can be increased by up to 26.13%, among which the epoxy-polyurethane combination has the best protection performance, with an acceleration attenuation ratio of up to 44.68%. This work provides a robust theoretical foundation and experimental basis for the reliable operation of MEMS devices, as well as for the design of protective structures in extreme environments. 展开更多
关键词 Continuous double pulse Protective structure Attenuation ratio MEMS devices
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A sparse moving array imaging approach for FMCW radar with dualaperture adaptive azimuth ambiguity suppression and adaptive QR decomposition
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作者 Yanwen Han Xiaopeng Yan +3 位作者 Jiawei Wang Sheng Zheng Hongrui Yu Jian Dai 《Defence Technology(防务技术)》 2025年第8期254-271,共18页
Range-azimuth imaging of ground targets via frequency-modulated continuous wave(FMCW)radar is crucial for effective target detection.However,when the pitch of the moving array constructed during motion exceeds the phy... Range-azimuth imaging of ground targets via frequency-modulated continuous wave(FMCW)radar is crucial for effective target detection.However,when the pitch of the moving array constructed during motion exceeds the physical array aperture,azimuth ambiguity occurs,making range-azimuth imaging on a moving platform challenging.To address this issue,we theoretically analyze azimuth ambiguity generation in sparse motion arrays and propose a dual-aperture adaptive processing(DAAP)method for suppressing azimuth ambiguity.This method combines spatial multiple-input multiple-output(MIMO)arrays with sparse motion arrays to achieve high-resolution range-azimuth imaging.In addition,an adaptive QR decomposition denoising method for sparse array signals based on iterative low-rank matrix approximation(LRMA)and regularized QR is proposed to preprocess sparse motion array signals.Simulations and experiments show that on a two-transmitter-four-receiver array,the signal-to-noise ratio(SNR)of the sparse motion array signal after noise suppression via adaptive QR decomposition can exceed 0 dB,and the azimuth ambiguity signal ratio(AASR)can be reduced to below-20 dB. 展开更多
关键词 Frequency modulated continuous wave (FMCW) Sparse motion array Range-azimuth imaging Azimuth ambiguity suppression DAAP Adaptive QR decomposition
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Continuity of truncated Hardy-Littlewood maximal function
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作者 WANG Yidong WU Jia YAN Dunyan 《中国科学院大学学报(中英文)》 CAS CSCD 北大核心 2024年第6期721-727,共7页
This paper focuses on the continuity of the truncated Hardy-Littlewood maximal function.We first show that the truncated Hardy-Littlewood maximal function is lower semi-continuous.Then by investigating the behavior of... This paper focuses on the continuity of the truncated Hardy-Littlewood maximal function.We first show that the truncated Hardy-Littlewood maximal function is lower semi-continuous.Then by investigating the behavior of the truncated Hardy-Littlewood maximal function when the truncated parameterγchanges,we obtain an equivalent condition of the continuity of the truncated Hardy-Littlewood maximal function. 展开更多
关键词 Hardy-Littlewood maximal function TRUNCATION CONTINUITY truncated parameter
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A new approach for recycling arsenic and tin from low-grade tin middlings using a self-sulfurization roasting
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作者 LI Lei XU Zhi-peng +4 位作者 HE Jun-li XIAO Yang SUN Yi-xuan LEI Yun ZHOU Juan 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3050-3067,共18页
Massive amounts of low-grade tin middlings have been produced from tin tailings,in which arsenic and tin are worthy to be recycled.Owing to high sulfur content in these tin middlings,a novel self-sulfurization roastin... Massive amounts of low-grade tin middlings have been produced from tin tailings,in which arsenic and tin are worthy to be recycled.Owing to high sulfur content in these tin middlings,a novel self-sulfurization roasting was proposed to transform,separate and recover arsenic and tin in this research.There was no extra curing agent to be added,which decreased the formation of pollutant S-containing gas.The self-sulfurization process involved a two-stage roasting of reduction followed by sulfurization.First in reduction roasting,FeAsS decomposed to FeS and As and the As then transformed to As_(4)(g)and As_(4)S_(4)(g),via which the arsenic was separated and recovered.The arsenic content in the first residue could be decreased to 0.72 wt.%.Accompanied with it,the FeS was firstly oxidized to Fe_(1−x)S and then to SO_(2)(g)by the coexisted Fe_(2)O_(3),and finally reduced and combined with the independent Fe_(2)O_(3)to form Fe_(1−x)S.In the followed sulfurization roasting,the Fe_(1−x)S sulfurized SnO_(2)to SnS(g),due to which tin could be recovered and its content in the second residue decreased to 0.01 wt.%.This study provided an efficient method to separate and recover arsenic and tin from low-grade tin middlings. 展开更多
关键词 low-grade tin middlings continuous sulfur transformation self-sulfurization separation of arsenic and tin RECYCLING
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美国《保健物理》(Health Physics)杂志英文摘要(2023年125卷第4期)(英文)
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《辐射防护》 CAS CSCD 北大核心 2024年第1期93-97,共5页
Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series:Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System Sean J.Domal1,Camilo M.Correa-Alfonso... Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series:Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System Sean J.Domal1,Camilo M.Correa-Alfonso1,Colin J.Paulbeck2,Keith T.Griffin3,4,Tatsuhiko Sato5,Sachiyo Funamoto6,Harry M.Cullings6,Stephen D.Egbert7,Akira Endo8,Nolan E.Hertel4,Choonsik Lee3,Wesley E.Bolch9(1.Medical Physics Program,College of Medicine,University of Florida,Gainesville,FL;2.Department of Radiology,Johns Hopkins University,Baltimore,MD;3.National Cancer Institute,National Institutes of Health,Rockville,MD;4.George W.Woodruff School of Mechanical Eng.,Georgia Institute of Technology,Atlanta,GA;5.Nuclear Science and Engineering Center,Japan Atomic Energy Agency,Tokaimura,Japan;6.Department of Statistics,Radiation Effects Research Foundation,Hiroshima,Japan;7.Consultant,San Diego,CA;8.Nuclear Science Research Institute,Japan Atomic Energy Agency,Tokaimura,Japan;9.J.Crayton Pruitt Family Department of Biomedical Eng.,University of Florida,Gainesville,FL USA)Abstract:Organ dosimetry data of the atomic bomb survivors and the resulting cancer risk models derived from these data are currently assessed within the DS02 dosimetry system developed through the Joint US-Japan Dosimetry Working Group.In DS02,the anatomical survivor models are limited to three hermaphroditic stylized phantoms—an adult(55 kg),a child(19.8 kg),and an infant(9.7 kg)—that were originally designed for the preceding DS86 dosimetry system.As such,organ doses needed for assessment of in-utero cancer risks to the fetus have continued to rely upon the use of the uterine wall in the adult non-pregnant stylized phantom as the dose surrogate for all fetal organs regardless of gestational age. 展开更多
关键词 doses 英文摘要 continued
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Optimal confrontation position selecting games model and its application to one-on-one air combat
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作者 Zekun Duan Genjiu Xu +2 位作者 Xin Liu Jiayuan Ma Liying Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期417-428,共12页
In the air combat process,confrontation position is the critical factor to determine the confrontation situation,attack effect and escape probability of UAVs.Therefore,selecting the optimal confrontation position beco... In the air combat process,confrontation position is the critical factor to determine the confrontation situation,attack effect and escape probability of UAVs.Therefore,selecting the optimal confrontation position becomes the primary goal of maneuver decision-making.By taking the position as the UAV’s maneuver strategy,this paper constructs the optimal confrontation position selecting games(OCPSGs)model.In the OCPSGs model,the payoff function of each UAV is defined by the difference between the comprehensive advantages of both sides,and the strategy space of each UAV at every step is defined by its accessible space determined by the maneuverability.Then we design the limit approximation of mixed strategy Nash equilibrium(LAMSNQ)algorithm,which provides a method to determine the optimal probability distribution of positions in the strategy space.In the simulation phase,we assume the motions on three directions are independent and the strategy space is a cuboid to simplify the model.Several simulations are performed to verify the feasibility,effectiveness and stability of the algorithm. 展开更多
关键词 Unmanned aerial vehicles(UAVs) Air combat Continuous strategy space Mixed strategy Nash equilibrium
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Strong Feller Property for SDEs with Super-linear Drift and Hölder Diffusion Coefficients
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作者 WANG Yanmin SHA Xiang GUO Zhongkai 《应用数学》 北大核心 2024年第4期1066-1073,共8页
In this paper,we investigate the strong Feller property of stochastic differential equations(SDEs)with super-linear drift and Hölder diffusion coefficients.By utilizing the Girsanov theorem,coupling method,trunca... In this paper,we investigate the strong Feller property of stochastic differential equations(SDEs)with super-linear drift and Hölder diffusion coefficients.By utilizing the Girsanov theorem,coupling method,truncation method and the Yamada-Watanabe approximation technique,we derived the strong Feller property of the solution. 展开更多
关键词 Super-linear drift Hölder continuous diffusion SDEs Strong Feller
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连续体结构拓扑优化应力约束凝聚化的ICM方法 被引量:24
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作者 隋允康 叶红玲 +1 位作者 彭细荣 张学胜 《力学学报》 EI CSCD 北大核心 2007年第4期554-563,共10页
为克服应力约束下拓扑优化问题约束数目多、应力敏度计算量大的困难,提出了应力约束化凝聚化的ICM方法.在利用Mises强度理论将应力约束转换成应变能约束后,提出了应力约束凝聚化的两条途径:其一为应力全局化的方法,其二为应力约束集成... 为克服应力约束下拓扑优化问题约束数目多、应力敏度计算量大的困难,提出了应力约束化凝聚化的ICM方法.在利用Mises强度理论将应力约束转换成应变能约束后,提出了应力约束凝聚化的两条途径:其一为应力全局化的方法,其二为应力约束集成化的方法.由此建立了多工况下以重量为目标、以凝聚化应变能为约束的连续体结构优化模型,并利用对偶理论对优化模型进行了求解.4个数值算例表明:该方法具有较高的计算效率,得到的拓扑结构比较合理,不仅适用于二维连续体结构,也适用于三维连续体结构. 展开更多
关键词 连续体 拓扑优化 ICM(independent continuous mapping)方法 应力约束凝聚化 多工况
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应力约束处理为应变能集成的连续体结构拓扑优化 被引量:16
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作者 隋允康 张学胜 龙连春 《计算力学学报》 EI CAS CSCD 北大核心 2007年第5期602-608,共7页
为克服应力约束下拓扑优化问题约束多、应力敏度计算量大的困难,本文提出了将应力约束处理为应变能集成的结构拓扑优化ICM方法。文中用几个典型算例对该方法进行了检验,结果表明:本方法优化效率较高,而且得到的结构最优拓扑较为合理。
关键词 拓扑优化 ICM(Independent CONTINUOUS Mapping)方法 K-S函数
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考虑地震行波效应的高铁连续梁桥梁轨互制 被引量:14
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作者 闫斌 戴公连 魏标 《振动与冲击》 EI CSCD 北大核心 2014年第5期87-90,共4页
为研究行波效应下高速铁路连续梁桥与无缝线路的非线性互制作用,采用带刚臂的梁单元模拟梁体,用非线性杆单元模拟梁轨间的互制作用,建立了考虑纵向和竖向地震动行波效应的梁轨相互作用模型。以我国沪昆线上某(60+100+60)m连续梁桥为算例... 为研究行波效应下高速铁路连续梁桥与无缝线路的非线性互制作用,采用带刚臂的梁单元模拟梁体,用非线性杆单元模拟梁轨间的互制作用,建立了考虑纵向和竖向地震动行波效应的梁轨相互作用模型。以我国沪昆线上某(60+100+60)m连续梁桥为算例,分析了轨道结构对梁体和墩台地震响应的影响,研究了纵向和竖向行波效应下钢轨和墩台的受力特点。研究表明:轨道的存在可提高系统基频,降低连续梁桥地震响应;但在地震动的行波效应下,钢轨纵向力最大值可达一致激励下的1.2倍;减小线路纵向阻力,增加桥墩刚度可减小地震作用下的钢轨应力;在检算钢轨时,还应累计竖向行波效应对钢轨受力的影响。 展开更多
关键词 铁路桥梁 无缝线路 连续梁桥 行波效应 梁轨相互作用 continuously WELDED RAIL (CWR)
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液压机械无级变速器机械变速机构的传动误差分析 被引量:3
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作者 雷贤卿 蔡振华 +1 位作者 张明柱 马文锁 《中国机械工程》 EI CAS CSCD 北大核心 2015年第23期3253-3259,共7页
以东方红某型号拖拉机液压机械无级变速器中的机械变速机构为研究对象,探究其传动误差随时间的变化规律,目的是减少变速器的功率损耗。利用当量啮合误差原理,建立变速器中行星齿轮组、定轴齿轮副和两者共同作用时的传动误差与时间的关... 以东方红某型号拖拉机液压机械无级变速器中的机械变速机构为研究对象,探究其传动误差随时间的变化规律,目的是减少变速器的功率损耗。利用当量啮合误差原理,建立变速器中行星齿轮组、定轴齿轮副和两者共同作用时的传动误差与时间的关系式。比较各挡位的总传动误差和行星齿轮组传动误差,得到瞬时总传动误差最大、最小的挡位以及总传动误差的主导因素。在角频率相同时,行星齿轮组传动误差和定轴齿轮副传动误差存在耦合关系。利用蒙特卡罗法,验证了研究所得规律的正确性。建立总传动误差与功率损耗的关系式,结果表明两者存在正比关系。以减小传动误差为目的,提出了减少变速器功率损耗的措施。 展开更多
关键词 拖拉机 液压机械无级变速器 传动误差 蒙特卡罗法 功率损耗 HYDRO-MECHANICAL continuous variable transmission (HMCVT)
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反渗透预处理及膜清洗方法 被引量:2
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作者 龚军军 贾铭椿 《海军工程大学学报》 CAS 2000年第6期66-70,共5页
基于预处理和膜清洗对于反渗透RO(reverseosmosis)长期稳定运行的重要性 ,介绍了常规预处理方法及其改进、膜法预处理等预处理方法 ,以及各种新型的物理、化学膜清洗方法 .
关键词 反渗透 预处理 膜清洗 CMF(continuous microfiltration)
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应该为结构拓扑优化的设计变量正名和处理方法顺言 被引量:4
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作者 彭细荣 隋允康 《北京工业大学学报》 CAS CSCD 北大核心 2016年第12期1787-1797,共11页
为了澄清拓扑化概念及促进发展,从基本概念入手,阐述了为拓扑变量正名、为有关映射顺言的必要性和迫切性.连续体结构拓扑优化方面的研究,以往学者们不注意厘清拓扑变量的概念,没有探讨其独立地位,而是依附于结构优化低层次,采用惩罚函... 为了澄清拓扑化概念及促进发展,从基本概念入手,阐述了为拓扑变量正名、为有关映射顺言的必要性和迫切性.连续体结构拓扑优化方面的研究,以往学者们不注意厘清拓扑变量的概念,没有探讨其独立地位,而是依附于结构优化低层次,采用惩罚函数使变量趋于0/1,有研究者于2004年意识到应当引进Heaviside函数取代惩罚函数.其实,笔者在1996年提出的独立连续映射(independent continuous mapping,ICM)方法中已经彻底解决了这些问题:定义独立层次的拓扑变量;采用阶跃函数及其逆函数的近似逼近.本文阐述了ICM方法的概念,并以频率约束拓扑优化为例详述了建模及求解.算例表明ICM方法因概念清晰显示出明显优势.《论语·子路篇》曰:"名不正则言不顺,言不顺则事不成."正名方可顺言,是时候该为结构拓扑优化的设计变量正名和处理方法顺言了. 展开更多
关键词 连续体结构拓扑优化 拓扑设计变量的独立化 近似逼近函数 惩罚函数 阶跃函数 Heaviside函数 独立连续映射(independent continuous mapping ICM)方法 变密度法
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结构拓扑优化中过滤函数对优化效率的影响 被引量:2
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作者 尚珍 隋允康 《机械设计与制造》 北大核心 2014年第8期244-246,共3页
基于ICM方法,建立了以重量为目标,分别在应力、位移、应力和位移联合约束下的连续体结构拓扑优化模型,并采用约束集成化方法对其进行求解。同时,利用幂指数形式下重量过滤函数与刚度过滤函数之间的不变量,针对不同幂指数的重量过滤函数... 基于ICM方法,建立了以重量为目标,分别在应力、位移、应力和位移联合约束下的连续体结构拓扑优化模型,并采用约束集成化方法对其进行求解。同时,利用幂指数形式下重量过滤函数与刚度过滤函数之间的不变量,针对不同幂指数的重量过滤函数,求出刚度过滤函数。最后,通过数值算例分析研究了不同过滤函数对连续体结构拓扑优化效率的影响,结果表明,在连续体结构拓扑优化中,应用非线性过滤函数,优化结果收敛快,迭代次数少,稳定性好。 展开更多
关键词 ICM(Independent CONTINUOUS and Mapping)方法 过滤函数 幂函数 效率
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基于chirp-z变换的斜视FMCW-SAR非线性尺度变换算法 被引量:2
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作者 于彬彬 刘畅 王岩飞 《雷达学报(中英文)》 2012年第1期69-75,共7页
该文针对调频连续波合成孔径雷达(Frequency Modulated Continuous Wave Synthetic Aperture Radar,FMCW-SAR)在斜视模式下聚焦精度降低的问题,提出一种非线性尺度变换chirp-z成像算法。该算法利用回波信号在多普勒域中距离向的非线性特... 该文针对调频连续波合成孔径雷达(Frequency Modulated Continuous Wave Synthetic Aperture Radar,FMCW-SAR)在斜视模式下聚焦精度降低的问题,提出一种非线性尺度变换chirp-z成像算法。该算法利用回波信号在多普勒域中距离向的非线性特性,通过引入一个非线性调频信号对回波信号进行基于chirp-z的非线性尺度变换,降低距离压缩和距离徙动校正的误差,提高雷达图像分辨率。采用该成像算法对点目标模拟回波的成像结果与原始chirp-z算法相比,距离向分辨率和图像对比度得到提高,方位向分辨率保持不变。 展开更多
关键词 调频连续波合成孔径雷达(Frequency Modulated Continuous Wave Synthetic APERTURE Radar FMCW-SAR) 斜视 非线性尺度变换 CHIRP-Z变换
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