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Performance evaluations on inner vs. outer decomposition first parallel join algorithms for two nested loop joins
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作者 Seo-Young NOH Heejun YOON +2 位作者 Il-Yeon YEO Yoon-su JEONG Hyungwoo PARK 《Journal of Central South University》 SCIE EI CAS 2014年第10期3873-3882,共10页
Two popular traditional join algorithms and their parallel versions are introduced. When designing join algorithms in serial computing environment, decomposing inner relation is considered as the right direction to sa... Two popular traditional join algorithms and their parallel versions are introduced. When designing join algorithms in serial computing environment, decomposing inner relation is considered as the right direction to save disk I/Os. However, two different decomposition algorithms are compared, such as inner vs. outer decomposition first algorithms for tuple-based and block-based nested loop joins, showing that the proposed approach is 20% better than general approach. Also lemmas are proved, when we have to use the outer decomposition first parallel join algorithms. 展开更多
关键词 parallel join performance inner decomposition outer decomposition
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DS-CDMA system outer loop power control and improvement for multi-service 被引量:3
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作者 Guan Mingxiang Guo Qing Li Xing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第3期453-460,共8页
When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control (OLPC) technology has to be adopted to enrich the target signal interference ratio (S... When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control (OLPC) technology has to be adopted to enrich the target signal interference ratio (Silt) and improve the system performance. The existing problems about DS-CDMA outer loop power control for multi-service are introduced and the power control theoretical model is analyzed. System simulation is adopted on how to obtain the theoretical performance and parameter optimization of the power control algorithm. The OLPC algorithm is improved and the performance comparisons between the old algorithm and the improved algorithm are given. The results show good performance of the improved OLPC algorithm and prove the validity of the improved method for multi-service. 展开更多
关键词 DS-CDMA outer loop power control MULTI-SERVICE performance.
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Transformations of phosphatidylinositol phosphates in the outer and inner nuclear membrane are linked to synthesis and restitution of cellular membranes 被引量:5
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作者 Amalia Slomiany Bronislaw L. Slomiany 《Health》 2011年第4期187-199,共13页
The ultimate goal in phosphoinositides cellular metabolism is to decipher their global functional organization and coordination of the com- partmentalized signaling processes. In this report we present evidence linkin... The ultimate goal in phosphoinositides cellular metabolism is to decipher their global functional organization and coordination of the com- partmentalized signaling processes. In this report we present evidence linking nuclear phos- phoinositides cycle with endoplasmic reticulum synthesis and function. The rapid transformation of [3H]inositol-labeled phosphoinositides in the intact nuclei (IN) was captured in chase studies for 0-5 min, followed by examination of phosphatidylinositides in the inner nuclear me- mbrane (INM), the outer nuclear membrane (ONM) and endoplasmic reticulum (ER). We revealed that synthesis of phosphatidylinositol phosphates (PIPs) occurs in ONM and the de- phosphorylation takes place in the INM. The rapid transformation of the radiolabeled PIPs in ONM reverberated in their appearance and successive transformation in INM, and in the 5min chased nuclei was tracked to ONM as the re- emerging radiolabeled phosphatidylinositol (PI). These chase-uncovered changes in ONM and INM PIPs profiles allow us to conclude that the observed conversions in the nuclear membrane continuum are induced by the lateral movement of the membrane and its transit from the cytosolic to nuclear and back to cytosolic environment. The suggested membrane synthesisinduced movement provides the means to transport the membrane- and the membrane lipid ligand-associated cytosolic proteins to the intranuclear spaces and renewal of INM. Export of the nuclear components interacting with the modified INM, by exiting from nuclear to cytosolic site, endows ER with a steady influx of the membrane that is conditioned to generate vesicles according to the nucleus delivered templates. 展开更多
关键词 Phosphatidylinositides PIPs Transformation RESTITUTION outer NUCLEAR MEMBRANE inner NUCLEAR MEMBRANE Endoplasmic Reticulum CELLULAR Membranes
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Lipophilic extractives of the inner and outer barks from six different Pinus species grown in Indonesia 被引量:2
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作者 Masendra Tatsuya Ashitani +1 位作者 Koetsu Takahashi Ganis Lukmandaru 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1329-1336,共8页
The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species(P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis) grown in Indonesia were investigated... The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species(P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis) grown in Indonesia were investigated by GC and GC–MS.Generally,the amounts of extractive contents were higher in the inner bark than in the outer bark except for P.merksuii.Fatty acids,monoterpenes,sesquiterpenes,resin acids,triterpenoids,and steroids were detected and quantified.Inner and outer barks differed not only in content of these compounds but also in their composition.Fatty acids and alcohols were the major classes of lipophilic compounds in the outer bark of P.caribeae, P.insularis,and P.montezumae.Steroids and triterpenoids were the dominant compounds identified in the inner bark of P.elliotii,P.insularis,and P.merkusii.Resin acids were the most abundant group in the inner bark of P.oocarpa whereas monoterpenes and sesquiterpenes were recorded in minor quantities in both bark layers of all species. 展开更多
关键词 Bark extractive LIPOPHILIC inner bark outer bark Pinus spp
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Viscous Inner and Outer Pressure Forming Method of Thin-walled Tube and Its Application 被引量:3
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作者 高铁军 LIU Yang WANG Zhongjin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第2期404-407,共4页
Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large de... Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35(the ratio between the maximum and minimum diameters of the part) can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes. 展开更多
关键词 thin-walled tube inner and outer pressure forming viscous medium integral forming
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Influence of Inner/Outer Stator Pole Ratio and Relative Position on Electromagnetic Performance of Partitioned Stator Switched Flux Permanent Magnet Machines 被引量:1
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作者 J.T.Shi Z.Q.Zhu 《CES Transactions on Electrical Machines and Systems》 CSCD 2019年第3期259-268,共10页
Based on the 6-pole outer stator(armature winding-stator),the influence of inner(permanent magnet-stator)/outer stator pole ratio n(n=NIS/NOS),stator relative positions and rotor pole number combinations on electromag... Based on the 6-pole outer stator(armature winding-stator),the influence of inner(permanent magnet-stator)/outer stator pole ratio n(n=NIS/NOS),stator relative positions and rotor pole number combinations on electromagnetic performance of partitioned stator switched flux permanent magnet(PM)machines(PS-SFPMMs)is investigated in this paper.Since the armature windings and PMs are located in two separated stators and PMs are stationary,PS-SFPMMs have high fault tolerance capabilities.To maximize the torque performance,the PM of inner stator pole should be aligned with outer stator pole when n is odd while the iron rib of inner stator pole should be aligned with outer stator pole when n is even.No matter what n is selected,the rotor pole number NR can be any integers except the phase number and its multiples.The analysis results indicate that the optimal NR is closed to(NIS+NOS)/2 and it is odd when n is odd while it is even when n is even.Meanwhile,symmetrical phase back-EMF waveform will be obtained when the ratio of Min(NOS,NIS)to the greatest common divisor of Min(NOS,NIS)and NR is even.Based on the optimal rotor pole numbers for 6-pole outer stator with different n and corresponding optimal relative position together with same rated copper loss,the average torque is improved by 18.4%,25.1%and 25.7%respectively in PS-SFPMMs with n equal to 2,3 and 4 when compared with PS-SFPMM with n equal to 1.The analyses are validated by experiment results of the prototype machine. 展开更多
关键词 inner/outer stator partitioned stator permanent magnet pole ratio relative position switched flux.
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Inner and outer pressure forming of nickel based super-alloy thin-walled part with variable diameter sections 被引量:3
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作者 王忠金 高铁军 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第2期285-290,共6页
A novel forming method of nickel based super-alloy thin-walled part with variable diameter sections was proposed by using inner and outer pressure with the visco-elasto-plastic pressure-carrying medium at room tempera... A novel forming method of nickel based super-alloy thin-walled part with variable diameter sections was proposed by using inner and outer pressure with the visco-elasto-plastic pressure-carrying medium at room temperature,and the principle of the method was provided.Experiments and FE simulations were carried out to analyze the deformation characteristics for the part with larger variable diameter ratio(35%).The results show that visco-elasto-plastic pressure-carrying medium can meet the requirements of the room-temperature deformation condition for nickel based super-alloy sheet.The inner and outer pressure forming with the visco-elasto-plastic pressure-carrying medium can meet the requirements of dimensional accuracy for the thin-walled part with variable diameter sections.The thinning of wall-thickness is less than 4%.This method provides a new approach for near-net shape forming of nickel based super-alloy thin-walled parts with variable diameter sections. 展开更多
关键词 压力成型技术 合金 直径 变量
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Outer Loop Power Control Algorithm Based on T-norms Information Fusion Technology in TD-SCDMA
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作者 孙毅 李芹 唐良瑞 《China Communications》 SCIE CSCD 2011年第3期180-188,共9页
An outer loop power control algorithm based on triangle norm(t-norm) information fusion technology is proposed in this paper.According to the difference between block error rate and bit error rate with target values,t... An outer loop power control algorithm based on triangle norm(t-norm) information fusion technology is proposed in this paper.According to the difference between block error rate and bit error rate with target values,the membership function calculation and level dividing of the two differences are dealt with.And then t-norm operator is used to fuse the two membership function values to determine the adjustment step-size.The algorithm can acquire the optimal adjustment step-size in the light of the channel status and avoid the overshoot phenomenon of the existing outer power control methods.As a result,the block error rate can converge to the target value quickly.Experiment results verify the excellent property of the algorithm. 展开更多
关键词 outer loop power control BLER t-norm operator information fusion TD-SCDMA
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Synchronization investigation of the network group constituted by the nearest neighbor networks under inner and outer synchronous couplings
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作者 李亭亭 李成仁 +4 位作者 王晨 何芳君 周光冶 孙景昌 韩非 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第12期572-576,共5页
A new synchronization technique of inner and outer couplings is proposed in this work to investigate the synchro- nization of network group. Some Haken-Lorenz lasers with chaos behaviors are taken as the nodes to cons... A new synchronization technique of inner and outer couplings is proposed in this work to investigate the synchro- nization of network group. Some Haken-Lorenz lasers with chaos behaviors are taken as the nodes to construct a few nearest neighbor complex networks and those sub-networks are also connected to form a network group. The effective node controllers are designed based on Lyapunov function and the complete synchronization among the sub-networks is realized perfectly under inner and outer couplings. The work is of potential applications in the cooperation output of lasers and the communication network. 展开更多
关键词 synchronization of network group inner and outer couplings Haken-Lorenz laser nearest neigh-bor network
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Forward masking in distinguishing inner and outer hair cell damage
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作者 DUAN Mao-li Department of Clinical Neuroscience,Karolinska Institutet Department of Otorhinolaryngology Head and Neck & Center for Hearing and Communication Research,Karolinska University Hospital,Sweden 《Journal of Otology》 2009年第1期23-25,共3页
Forward Masking Temporal audiotory resolution is the ability of the auditory system to resolve auditory signals in the time domain. Forward masking is a means of studying temporal resolution where one tone, the probe,... Forward Masking Temporal audiotory resolution is the ability of the auditory system to resolve auditory signals in the time domain. Forward masking is a means of studying temporal resolution where one tone, the probe, is masked by a preceding tone, the masker. Forward masking is 展开更多
关键词 CELL Forward masking in distinguishing inner and outer hair cell damage ABR
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Sanitary Sewage Treatment with Jet Inner-loop Bioreactor
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作者 WenQin-xue ChenZhi-qiang +1 位作者 LuBing-nan WenYan 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第3期388-394,共7页
A jet inner-loop bioreactor (JIBR) was used to treat synthetic sanitary sewage with low, medium and high COD load. The experimental results show that it could meet discharge standard at 20\|30 min of HRT (hydraulic re... A jet inner-loop bioreactor (JIBR) was used to treat synthetic sanitary sewage with low, medium and high COD load. The experimental results show that it could meet discharge standard at 20\|30 min of HRT (hydraulic retention time) for low COD concentration and 60\|120 min of HRT for medium and high COD concentration. The maximal COD volume loading and COD sludge loading of 27 kg\5m -3 \5d -1 and 5 kg/d per kg MLSS were acheived respectively, that were 10\|20 times higher than those of traditional wastewater treatment processes. The BOD 5 removal efficiency was more than 90% and NH + 4 —N more than 85%. The study on the activity showed that the oxygen consumption rate of the activated sludge in the JIBR was 39.13 mg\5L -1 \5h -1 , which was 1.7 times higher than that of the SBR(Sequencing Batch Reactor) and the dominant bacteria in jet inner\|loop bioreactor was Pseudomonas species. 展开更多
关键词 jet inner-loop bioreactor sanitary sewage volume loading sludge loading
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On the System-Level Analysis of Outer Loop Link Adaptation for IEEE 802,16e Systems
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作者 Andre M. Cavalcante Edgar B. Sotlza +3 位作者 Juliano J. Bazzo Marco J. Souza Lauri Kuru Jani Moilanen 《通讯和计算机(中英文版)》 2012年第5期568-575,共8页
关键词 无线通信系统 链路自适应 IEEE 级分 外环 高速下行分组接入 标准化委员会 HSDPA
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基于功率外环控制的双馈风电机组故障穿越通用电磁暂态建模
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作者 朱大锐 程嘉康 +2 位作者 段建东 陈杰 邓俊 《电力系统自动化》 北大核心 2026年第2期197-207,共11页
当前风机厂家众多,控制逻辑各有差异,且多是控制结构未知的封装模型,模型应用存在较大局限性。而风电并网系统稳定性研究需要能准确反映实际风电机组各种典型故障穿越全过程响应特性的电磁暂态模型。为了解决此问题,对大量风机厂家封装... 当前风机厂家众多,控制逻辑各有差异,且多是控制结构未知的封装模型,模型应用存在较大局限性。而风电并网系统稳定性研究需要能准确反映实际风电机组各种典型故障穿越全过程响应特性的电磁暂态模型。为了解决此问题,对大量风机厂家封装模型进行故障穿越特性测试,分析测试数据并提出适用于对称、不对称故障的低、高电压穿越分阶段的全过程通用响应曲线,通过设计的每阶段转子侧、网侧功率外环参考值表达式并修改外环有功功率和无功功率参考值及控制参数,可便捷模拟不同厂家风机从故障发生到响应恢复的全过程。通过与主流厂家两种封装模型测试数据对比及误差计算分析,验证了所提建模方法对全部故障工况的适应性及通用性。 展开更多
关键词 双馈风电机组 电磁暂态模型 功率外环控制 故障穿越 建模
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内蒙古达里湖及岗更湖东北雅罗鱼D-loop基因序列及多样性研究 被引量:2
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作者 罗旭光 齐景伟 +3 位作者 安晓萍 乌兰 姚珺 李蓓 《南方水产科学》 CAS CSCD 北大核心 2014年第2期92-96,共5页
文章对内蒙古达里湖和岗更湖东北雅罗鱼(Leuciscus waleckii Dybowski)的mtDNA D-loop序列进行扩增,获得了896 bp的同源基因序列,得到的同源基因片段中A、T、C和G碱基的平均含量,达里湖群体为32.0%、32.2%、21.3%和14.5%;岗更湖群体为32... 文章对内蒙古达里湖和岗更湖东北雅罗鱼(Leuciscus waleckii Dybowski)的mtDNA D-loop序列进行扩增,获得了896 bp的同源基因序列,得到的同源基因片段中A、T、C和G碱基的平均含量,达里湖群体为32.0%、32.2%、21.3%和14.5%;岗更湖群体为32.0%、32.2%、21.4%和14.5%;达里湖和岗更湖鱼群D-loop基因CG含量相当,未见明显差异。2个群体内和群体间都存在丰富的序列多态性,两湖群体的D-loop基因896个位点中存在可变位点33个,其余位点较为保守;达里湖30尾鱼D-loop基因含有多态性位点/突变位点21个,11个单倍型;岗更湖30尾鱼D-loop基因含有多态性位点/突变体位点31个,17个单倍型;岗更湖鱼群D-loop基因多样性高于达里湖。遗传距离计算显示,岗更湖和达里湖鱼群之间的平均遗传距离为0.007 0;达里湖鱼群之间的平均遗传距离为0.003 6;岗更湖鱼群之间的平均遗传距离为0.007 4。岗更湖鱼群D-loop基因的平均遗传距离大于达里湖鱼,前者群体D-loop基因进化速度大于后者。 展开更多
关键词 东北雅罗鱼 内蒙古 D—loop基因 多样性 遗传距离
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不同连接形式冻结管承载力及变形对比研究
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作者 王锦恒 王彬 +1 位作者 张子浩 梁秀玲 《煤炭工程》 北大核心 2026年第1期208-215,共8页
为提升人工冻结法的安全性与可靠性,通过对比不同规格及低温条件下的外衬与内衬焊接构造冻结管的力学性能差异,明确其承载能力和变形特性对工程选型的影响。采用内衬与外衬两种不同焊接方式的冻结管,分别选取Φ140 mm×5 mm+Φ140 m... 为提升人工冻结法的安全性与可靠性,通过对比不同规格及低温条件下的外衬与内衬焊接构造冻结管的力学性能差异,明确其承载能力和变形特性对工程选型的影响。采用内衬与外衬两种不同焊接方式的冻结管,分别选取Φ140 mm×5 mm+Φ140 mm×6 mm、Φ140 mm×6 mm+Φ140 mm×6 mm、Φ140 mm×5 mm+Φ140 mm×5 mm三种规格,在模拟低温环境中系统测试其轴向承载力和挠度变形特性,结果显示:在相同尺寸和实验条件的对比下,外衬构造冻结管的平均承载力明显低于内衬构造管,但其挠度值更高。这表明焊接构造形式对冻结管力学性能具有直接影响,内衬构造抗压性能更优,而外衬构造则具有更强的变形适应性能。采用曲率检验法对两种不同焊接方式的冻结管进行安全评估,结果表明两种焊接方式的冻结管均满足安全规范要求。 展开更多
关键词 人工冻结法 冻结管 焊接构造 内衬 外衬 力学特性
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毛竹结构与应用场景对竹牙刷毛束拉力的影响
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作者 郝兆锋 张文福 +5 位作者 张建 胡鸣 王洪艳 赵莹 袁少飞 任文庭 《北京林业大学学报》 北大核心 2026年第1期197-207,共11页
【目的】竹材因其各向异性,在相同工艺条件下加工的竹牙刷质量存在差异。本研究旨在探讨不同密度竹材加工的竹牙刷及其在不同应用场景下的毛束拉力性能规律,以提高竹牙刷质量的可控性。【方法】将原竹加工为竹牙刷,在加工过程中统计规... 【目的】竹材因其各向异性,在相同工艺条件下加工的竹牙刷质量存在差异。本研究旨在探讨不同密度竹材加工的竹牙刷及其在不同应用场景下的毛束拉力性能规律,以提高竹牙刷质量的可控性。【方法】将原竹加工为竹牙刷,在加工过程中统计规格竹条的密度(ρ),并按密度对竹牙刷分类。对比测试塑料牙刷与不同密度竹牙刷的毛束拉力性能,选取相同密度区间的竹牙刷,通过不同温度水浴处理与吸水-干燥循环处理模拟不同的应用场景,测试竹牙刷在使用过程中的耐久性。另外,通过测试相同密度区间下竹牙刷的竹青/竹黄面以及刷头不同孔位的毛束拉力性能,探讨竹牙刷最佳加工工艺条件。利用超景深显微镜、扫描电镜(SEM)和显微CT设备观察并分析竹牙刷植毛孔的微观形貌结构。【结果】(1)不同密度竹材制成的竹牙刷在毛束拉力性能上存在显著差异,毛束拉力随竹材密度增加而显著提高。密度大于0.70 g/cm^(3)的竹牙刷毛束拉力均满足国标15 N的要求,密度大于0.75 g/cm^(3)的竹牙刷在毛束拉力性能上优于塑料牙刷。(2)0.75≤ρ<0.80竹牙刷的耐久性测试结果显示:常温水浴处理的竹牙刷毛束拉力稳定在15.42~16.69 N之间;即使在6天吸水-干燥循环处理后,拉力下降至15.6 N,仍符合国标要求。(3)竹青面植毛牙刷的毛束拉力均值为19.55 N,高于竹黄面的17.89 N。刷头外圈孔位的毛束拉力均值(18.21 N)高于刷头整体毛束拉力性能(17.81 N),内圈孔位(17.23 N)低于刷头整体毛束拉力性能。结合内圈与外圈孔位的毛束拉力值的方差分析(p<0.05),表明边缘孔位表现出更优的毛束拉力性能。(4)植毛孔形貌结构结果显示,竹材天然结构为嵌入孔内的金属片提供了良好的接触界面。【结论】较高密度竹材制备的竹牙刷具备更优的毛束拉力性能,同时在日常使用条件下其毛束拉力性能表现稳定,可替代市场上的一般塑料牙刷,展现出良好的应用潜力。根据不同孔位及植毛面对毛束拉力的差异化影响,在实际生产中可采取差异化设计策略优化孔位分布和植毛部位,从而提升竹牙刷的可靠性与耐久性。 展开更多
关键词 以竹代塑 毛竹牙刷 毛束拉力 竹材密度-力学关联 各向异性微结构 吸湿-干燥循环耐久性 竹青/竹黄植毛面 植毛孔形貌
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基于模型无关元学习的自适应参数更新模型
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作者 刘书鹏 于复兴 +1 位作者 索依娜 袁书娟 《现代电子技术》 北大核心 2026年第3期97-104,共8页
模型无关元学习(MAML)目前大多在内外循环中使用梯度下降进行参数更新,而这其中面临的问题是计算过程中的梯度不稳定,在高维参数空间中,容易导致梯度爆炸或梯度消失的问题。此外,传统梯度下降法在复杂的损失表面上收敛速度较慢,对学习... 模型无关元学习(MAML)目前大多在内外循环中使用梯度下降进行参数更新,而这其中面临的问题是计算过程中的梯度不稳定,在高维参数空间中,容易导致梯度爆炸或梯度消失的问题。此外,传统梯度下降法在复杂的损失表面上收敛速度较慢,对学习率非常敏感,选择不当会显著影响模型性能和训练稳定。为解决上述问题,文中提出一种基于MAML的自适应参数更新模型,将Adam优化算法引入MAML的Inner-update和Outer-update中构建新型参数更新框架,改善参数的收敛速度和模型的稳定性。通过实验分析关键性能指标,结果表明,文中提出的改进方法在分类效果上十分出色,与相同实验环境下训练的对比模型相比,基于MAML的自适应参数更新模型有效提升了分类的准确率,对元学习在其他领域的探索与实践具有一定的参考价值。 展开更多
关键词 模型无关元学习 内外循环 自适应 梯度优化 ADAM 自动参数更新
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基于元学习的跨语言知识图谱实体对齐框架
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作者 陈壮壮 邓怡辰 +1 位作者 余敦辉 肖奎 《计算机科学》 北大核心 2026年第1期271-277,共7页
跨语言知识图谱实体对齐是连接不同语言知识图谱的关键步骤,在多语言信息检索、数据融合等任务中有重要作用。然而,现有的实体对齐方法依赖知识图谱中的多种信息,难以很好地处理稀疏知识图谱实体对齐任务,并且对新的语言的适应性较差。... 跨语言知识图谱实体对齐是连接不同语言知识图谱的关键步骤,在多语言信息检索、数据融合等任务中有重要作用。然而,现有的实体对齐方法依赖知识图谱中的多种信息,难以很好地处理稀疏知识图谱实体对齐任务,并且对新的语言的适应性较差。针对该问题,提出了基于元学习的跨语言实体对齐框架。该框架总体分为外循环与内循环两个阶段:在外循环阶段,通过基于任务相似度的采样方法选取出多个任务,然后对模型进行多任务联合训练,构建教师模型;在内循环阶段,利用外循环阶段训练好的教师模型指导学生模型进行训练和实体对齐任务,提升学生模型实体对齐的性能和泛化性。在SRPRS和WK31-60K数据集上的实验结果表明,所提框架在实体对齐问题中,Hits@1指标平均提升3.5%,Hits@10指标平均提升4.0%,MRR指标平均提升6.3%。 展开更多
关键词 元学习 跨语言知识图谱 实体对齐 外循环 内循环 泛化能力
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基于电机驱动系统的DAB变换器控制优化方法
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作者 李东东 刘晨亮 +1 位作者 吉裕晖 孙震威 《微特电机》 2026年第1期61-68,共8页
针对微特电机驱动控制系统中,双有源桥(dual active bridge,DAB)变换器在高频调制过程中易产生较大电流应力,导致器件温升高、寿命衰减及负载扰动下系统稳定性下降等问题,本文提出一种改进型双移相优化调制策略。该方法基于双有源桥拓扑... 针对微特电机驱动控制系统中,双有源桥(dual active bridge,DAB)变换器在高频调制过程中易产生较大电流应力,导致器件温升高、寿命衰减及负载扰动下系统稳定性下降等问题,本文提出一种改进型双移相优化调制策略。该方法基于双有源桥拓扑,建立双移相调制下的功率传输模型与电流应力数学模型,采用拉格朗日乘数法求解最优移相比组合,并进一步推导多功率场景下的电流应力解析表达式;在控制器设计方面,引入电感电流内环补偿机制,提高系统对电机驱动过程中负载变化的动态响应能力。MATLAB/Simulink仿真结果表明,该方法在典型微特电机负载工况下能有效降低变换器的电流应力,缩短暂态响应时间,并改善输出电压纹波,对提升微特电机控制系统的稳态与暂态性能具有良好效果,为高效能电机驱动供电模块的优化设计提供理论依据。 展开更多
关键词 微特电机 双有源桥拓扑 最优移相比 电流内环控制 暂态响应优化
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大规模海上风电经柔直送出系统的受端功率协调控制策略
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作者 彭穗 李峰 +3 位作者 黄小威 唐玉烽 彭发喜 王彦峰 《南方电网技术》 北大核心 2026年第1期131-142,共12页
基于模块化多电平换流器(modular multilevel converter,MMC)的柔性直流输电技术因其效率高、控制灵活、便于扩展至多端系统等优势,逐渐成为海上风电并网的重要方式。海上风电场送出的有功功率具有随机性和波动性,大范围的功率波动可能... 基于模块化多电平换流器(modular multilevel converter,MMC)的柔性直流输电技术因其效率高、控制灵活、便于扩展至多端系统等优势,逐渐成为海上风电并网的重要方式。海上风电场送出的有功功率具有随机性和波动性,大范围的功率波动可能造成受端换流站功率越限、直流电压越限和交直流系统功率回环等问题。为此,提出了两种适用于大规模海上风电经柔直送出系统的受端功率协调控制策略。首先,介绍了送出系统基本结构和MMC控制策略。然后,设计了受端有功功率自均衡控制策略和共用外环的定直流电压控制,两种策略具有不同的技术特点,但均能够实现多个受端换流站之间的有功功率合理分配,从而避免不必要的功率越限、电压越限和功率回环等问题。最后,利用PSCAD/EMTDC仿真验证了两种控制策略的有效性。 展开更多
关键词 风电场 功率协调控制 有功功率自均衡 共用外环
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