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Acute zonal occult outer retinopathy complex and angioid streaks:a case report
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作者 Zhen-Yu Liu Hang Zhang +1 位作者 Xiu-Li Sun Xiao-Yan Peng 《International Journal of Ophthalmology(English edition)》 2026年第1期193-196,共4页
Dear Editor,We present a case of acute zonal occult outer retinopathy(AZOOR)complex in a myopic patient with angioid streaks(ASs).A 19-year-old female has been experiencing visual field defects in her left eye for mor... Dear Editor,We present a case of acute zonal occult outer retinopathy(AZOOR)complex in a myopic patient with angioid streaks(ASs).A 19-year-old female has been experiencing visual field defects in her left eye for more than 3y.She was diagnosed with ASs and choroiditis at a local hospital.She has a seven-year history of bilateral high myopia.A fundus examination confirmed the presence of ASs and myopic fundus changes in both eyes.Multimodal imaging revealed an AZOOR complex in the left eye. 展开更多
关键词 myopic fundus changes zonal occult outer retinopathy azoor complex Angioid Streaks Acute Zonal Occult outer Retinopathy MYOPIA fundus examination angioid streaks ass azoor complex
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Source process of the 2021 M_(W)6.6 outer rise earthquake off the west coast of northern Sumatra
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作者 Bagus Adi Wibowo Hongru Li +5 位作者 Anisa Nurbaeti Rahayu Ling Bai Supriyanto Rohadi Putu Hendra Widyadharma Abraham Arimuko Suko Prayitno Adi 《地球与行星物理论评(中英文)》 2026年第1期51-61,共11页
The complexity of the seismicity pattern for the subduction zone along the oceanic plate triggered the outer rise events and revealed cyclic tectonic deformation conditions along the plate subduction zones.The outer r... The complexity of the seismicity pattern for the subduction zone along the oceanic plate triggered the outer rise events and revealed cyclic tectonic deformation conditions along the plate subduction zones.The outer rise earthquakes have been observed along the Sunda arc,following the estimated rupture area of the 2005 M_(W)8.6 Nias earthquakes.Here,we used kinematic waveform inversion(KIWI)to obtain the source parameters of the 14 May 2021 M_(W)6.6 event off the west coast of northern Sumatra and to define the fault plane that triggered this outer rise event.The KIWI algorithm allows two types of seismic source to be configured:the moment tensor model to describe the type of shear with six moment tensor components and the Eikonal model for the rupture of pure double-couple sources.This method was chosen for its flexibility to be applied for different sources of seismicity and also for the automated full-moment tensor solution with real-time monitoring.We used full waveform traces from 8 broadband seismic stations within 1000 km epicentral distances sourced from the Incorporated Research Institutions for Seismology(IRIS-IDA)and Geofon GFZ seismic record databases.The initial origin time and hypocenter values are obtained from the IRIS-IDA.The synthetic seismograms used in the inversion process are based on the existing regional green function database model and were accessed from the KIWI Tools Green's Function Database.The obtained scalar seismic moment value is 1.18×10^(19)N·m,equivalent to a moment magnitude M_(W)6.6.The source parameters are 140°,44°,and−99°for the strike,dip,and rake values at a centroid depth of 10.2 km,indicating that this event is a normal fault earthquake that occurred in the outer rise area.The outer rise events with normal faults typically occur at the shallow part of the plate,with nodal-plane dips predominantly in the range of 30°-60°on the weak oceanic lithosphere due to hydrothermal alteration.The stress regime around the plate subduction zone varies both temporally and spatially due to the cyclic influences of megathrust earthquakes.Tensional outer rise earthquakes tend to occur after the megathrust events.The relative timing of these events is not known due to the viscous relaxation of the down going slab and poroelastic response in the trench slope region.The occurrence of the 14 May 2021 earthquake shows the seismicity in the outer rise region in the strongly coupled Sunda arc subduction zone due to elastic bending stress within the duration of the seismic cycle. 展开更多
关键词 outer rise earthquake kinematic waveform inversion source process
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Müller cells are activated in response to retinal outer nuclear layer degeneration in rats subjected to simulated weightlessness conditions 被引量:1
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作者 Yuxue Mu Ning Zhang +7 位作者 Dongyu Wei Guoqing Yang Lilingxuan Yao Xinyue Xu Yang Li Junhui Xue Zuoming Zhang Tao Chen 《Neural Regeneration Research》 SCIE CAS 2025年第7期2116-2128,共13页
A microgravity environment has been shown to cause ocular damage and affect visual acuity,but the underlying mechanisms remain unclear.Therefore,we established an animal model of weightlessness via tail suspension to ... A microgravity environment has been shown to cause ocular damage and affect visual acuity,but the underlying mechanisms remain unclear.Therefore,we established an animal model of weightlessness via tail suspension to examine the pathological changes and molecular mechanisms of retinal damage under microgravity.After 4 weeks of tail suspension,there were no notable alterations in retinal function and morphology,while after 8 weeks of tail suspension,significant reductions in retinal function were observed,and the outer nuclear layer was thinner,with abundant apoptotic cells.To investigate the mechanism underlying the degenerative changes that occurred in the outer nuclear layer of the retina,proteomics was used to analyze differentially expressed proteins in rat retinas after 8 weeks of tail suspension.The results showed that the expression levels of fibroblast growth factor 2(also known as basic fibroblast growth factor)and glial fibrillary acidic protein,which are closely related to Müller cell activation,were significantly upregulated.In addition,Müller cell regeneration and Müller cell gliosis were observed after 4 and 8 weeks,respectively,of simulated weightlessness.These findings indicate that Müller cells play an important regulatory role in retinal outer nuclear layer degeneration during weightlessness. 展开更多
关键词 glial fibrous acidic protein GLIOSIS Müller cells nerve growth factor neural differentiation neurodegeneration proteomic retinal degeneration retinal outer nuclear layer simulated weightlessness
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Ownership of Mineral Resources in Outer Space
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作者 Kassim B.Kipanga Taw-Wong Youyod 《Aerospace China》 2025年第2期55-68,共14页
Ownership is an increasingly important conflict in outer space at this moment in time.Despite the principle in the Outer Space Treaty(1967),that emphasizes the importance of all states'free access to outer space b... Ownership is an increasingly important conflict in outer space at this moment in time.Despite the principle in the Outer Space Treaty(1967),that emphasizes the importance of all states'free access to outer space based on equality for exploration and use.Moreover,outer space including the Moon and other celestial bodies is not subject to national appropriation by claim of sovereignty,by means of use or occupation,or by any other means.However,outer space activity is not free from sovereignty and jurisdiction after all.Anyway,the legal situation relating to space resource exploitation and utilization activities under the adoption of United Nations is a challenge.Some scholars implied that the Outer Space Treaty(1967)clearly prohibits appropriation of whole celestial bodies but is far less clear concerning the rights of over-extracted resources.Nevertheless,the Moon Agreement(1979)promotes the idea of property ownership of over-extracted resources.It permits states to collect and remove samples of lunar minerals and other substances for further interest in scientific investigation.The application of the Moon Agreement(1979)is not only to the Moon itself but to other celestial bodies,thus potentially covering the planets and asteroids where the mining potential is considered to be limitless.Under this circumstance,numerous countries,such as the United States,Luxembourg,The United Arab Emirates,and Japan have enacted legal regimes that glorify the rights of their entities in mineral resources in outer space.However,these regimes could be disputed under the international legal framework if countries have merely interpreted and applied their rights and obligations on a national level as they understand them.Therefore,this paper purports to clarify the ownership rights in outer space and analyze the purpose of the legal situation relating to space resource exploitation and utilization activities under the adoption of the United States,Luxembourg,The United Arab Emirates,and Japan. 展开更多
关键词 outer Space Treaty(1967) Moon Agreement(1979) mineral resources in outer space
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Electroacupuncture attenuates retinal ischemia/reperfusion injury by protecting the outer blood-retina barrier via enkephalins activate delta opioid receptor
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作者 Ping CHEN Xian-dan ZHU +5 位作者 Run-jie GUO Yong XIA Jing-ling JIN Nan-ge JIN Ying-min GU Xue-song TIAN 《World Journal of Acupuncture-Moxibustion》 2025年第3期238-253,共16页
Objectives Retinal ischemia-reperfusion(RIR)injury results in irreversible visual impairments.The disruption of the outer blood-retinal barrier(OBRB)is a major ocular pathogenic process that RIR injury affects.Current... Objectives Retinal ischemia-reperfusion(RIR)injury results in irreversible visual impairments.The disruption of the outer blood-retinal barrier(OBRB)is a major ocular pathogenic process that RIR injury affects.Current clinical strategies are limited.This study aimed to elucidate how electroacupuncture(EA)protects the OBRB against RIR injury.Methods Male Wistar rats(7 weeks old,250 g to 280 g)were used in this study.Three independent experiments were conducted.First,Opioid peptide levels were quantified using enzyme-linked immunosorbent assay(ELISA).42 rats were randomly divided into 7 groups(n=6/group):Control:No treatment;high intraocular pressure(HIOP):Acute intraocular pressure elevation-induced RIR injury;HIOP+SHAM EA:RIR injury+sham EA at Xinming(Extra acupoint)and Jingming(BL1)for 30 min(shallow needle insertion but without electric stimulation);HIOP+2 Hz EA:RIR injury+2 Hz EA at Xinming and BL1 for 30 min;HIOP+100 Hz:RIR injury+100 Hz EA at Xinming and BL1 for 30 min;HIOP+2/100 Hz EA:RIR injury+2/100 Hz EA at Xinming and BL1 for 30 min;HIOP+4/20 Hz EA:RIR injury+4/20 Hz EA at Xinming and BL1 for 30 min.Second,retinal morphology was assessed by hematoxylin and eosin(HE)staining.20 rats were randomly allocated into 4 groups(n=5/group):Control:No treatment;HIOP:Acute intraocular pressure elevation-induced RIR injury;HIOP+SHAM EA:RIR injury+sham EA at Xinming and BL1 for 30 min(shallow needle insertion but without electric stimulation);HIOP+2 Hz EA:RIR injury+2 Hz EA at Xinming and BL1 for 30 min.Third,the permeability of OBRB was evaluated using the fluorescein isothiocyanate(FITC)-dextran leakage assay.15 rats were randomly divided into 5 groups(n=3/group):Control:No treatment;HIOP:Acute intraocular pressure elevation-induced RIR injury;HIOP+SHAM EA:RIR injury+sham EA at Xinming and BL1 for 30 min(shallow needle insertion but without electric stimulation);HIOP+2 Hz EA:RIR injury+2 Hz EA at Xinming and BL1 for 30 min;Nal+HIOP+2 Hz EA:Intravitreal injection ofδ-opioid receptor antagonist Naltridole(10µl,100 nM)30 min before RIR injury induction,followed by 2 Hz EA treatment at Xinming and BL1 for 30 min.In vitro studies examined enkephalins'effects on oxygen–glucose deprivation/reperfusion(OGD/R)induced injury in ARPE‐19 cells.Cell viability was evaluated by cell counting kit-8(CCK-8)assay,and morphological changes were recorded by Molecular Devices.Apoptosis was detected by Annexin V-FITC flow cytometry.Delta opioid receptor(DOR)expression in total protein and membrane protein were analyzed by western blotting(WB).Immunofluorescence(IF)staining and WB assessed ZO-1 and Claudin-19.For cell-based assays,n indicates the number of biologically independent replicates.Results It was found that 2 Hz EA treatment increased enkephalins(methionine-enkephalin and leucine-enkephalin)levels(P<0.01),restoring the increased retinal thickness(P<0.05)and mitigating RGCs loss(P<0.05)post-RIR injury.FITC-dextran leakage in the outer retina was ameliorated by 2 Hz EA(P<0.05),reversibly countered by Naltrindole(P<0.05),a DOR antagonist.Treatment with 30µM enkephalins enhanced ARPE-19 cell viability(P<0.001,P<0.0001)and inhibited apoptosis(P<0.0001).Enkephalins elevated DOR levels in total protein(P<0.05)and membrane protein fractions(P<0.001,P<0.0001),as well as elevated ZO-1(P<0.001,P<0.01)and Claudin-19(P<0.0001,P<0.001)levels following OGD/R,counteracted by Naltrindole.Conclusion It was found that 2 Hz EA inhibits the breakdown of OBRB via enkephalins activate DOR in RIR injury. 展开更多
关键词 Retinal ischemia-reperfusion injury outer blood retinal barrier ELECTROACUPUNCTURE Delta opioid receptor ENKEPHALINS
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Clinical manifestation and multimodal images of Chinese acute zonal occult outer retinopathy patients
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作者 Shu-Lin Liu Xin-Yu Zhao +1 位作者 Jing-Yuan Yang You-Xin Chen 《International Journal of Ophthalmology(English edition)》 2025年第10期1914-1921,共8页
AIM:To comprehensively examine the clinical presentations,multimodal images,and long-term follow-up of Chinese patients with acute zonal occult outer retinopathy(AZOOR),a rare inflammatory disorder.METHODS:This was a ... AIM:To comprehensively examine the clinical presentations,multimodal images,and long-term follow-up of Chinese patients with acute zonal occult outer retinopathy(AZOOR),a rare inflammatory disorder.METHODS:This was a retrospective study.A total of 20 patients(32 eyes)were included.The medical records and multimodal imaging,including wide-field fundus photography,wide-field fundus autofluorescence(FAF),and swept-source optical coherence tomography(SS-OCT)were analyzed.RESULTS:The study included 20 patients with a mean age of 38.2±10.9y,and females accounted for 60%.Lesions could involve peripapillary areas,macular region,and peripheral retina.The mean best-corrected visual acuity(BCVA)at presentation was 0.38±0.60 logMAR,with no significant difference in visual acuity between acute cases(within 6mo of onset)and chronic cases(beyond 6mo of onset;P=0.390).There was no statistically significant difference in visual acuity between eyes of acute case(within 6mo of onset)and the chronic case(beyond 6mo of onset).In some chronic case,FAF examination revealed the presence of a hyperautofluorescent(hyperAF)ring around the macular area(6/18),a phenomenon not observed in the acute case(P=0.024).A higher proportion of chronic cases showed predominantly hypoautofluorescent(hypoAF)lesions compared to the acute case(13/18 vs 2/14,P=0.0016).SS-OCT examination showed that both acute and chronic cases exhibited hyperreflective dots above the retinal pigment epithelium(RPE),and ellipsoid zone(EZ)and RPE damage.In the chronic case,eyes with hyperreflective dots above the RPE were more likely to exhibit EZ and RPE damage in the macular region compared to those without these dots.CONCLUSION:Multimodal imaging plays a crucial role in the follow-up of patients with AZOOR.In chronic cases of AZOOR,the presence of hyperreflective dots above the RPE indicates a higher likelihood of outer retinal involvement in the macular region.This study provides critical insights into the complex presentation and progression of AZOOR. 展开更多
关键词 acute zonal occult outer retinopathy fundus autofluorescence optical coherence tomography hyperreflective dots
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Jurisprudential Reflections on the Evolving Dynamics of Outer Space Governance
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作者 FENG Guodong 《Aerospace China》 2025年第2期23-28,共6页
The legal framework for outer space governance,centered on the“Five Major Treaties”,is facing significant challenges.In the face of numerous variables that will shape the future order of outer space,an intrinsic dem... The legal framework for outer space governance,centered on the“Five Major Treaties”,is facing significant challenges.In the face of numerous variables that will shape the future order of outer space,an intrinsic demand for transformation has emerged within the governance of outer space.Under the leadership of the new wave of space technology revolutions and commercial innovations,outer space governance will undergo a profound transformation.New theories in space law will emerge,engage in long-term competition,and ultimately contribute to the formation of a completely new governance structure. 展开更多
关键词 outer space governance transformation trends commercial space public rights in extraterrestrial activities
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Improved Sensitivity Encoding Parallel Magnetic Resonance Imaging Reconstruction Algorithm Based on Efficient Sum of Outer Products Dictionary Learning
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作者 DUAN Jizhong SU Yan 《Journal of Shanghai Jiaotong university(Science)》 2025年第3期561-571,共11页
Sensitivity encoding(SENSE)is a parallel magnetic resonance imaging(MRI)reconstruction model by utilizing the sensitivity information of receiver coils to achieve image reconstruction.The existing SENSE-based reconstr... Sensitivity encoding(SENSE)is a parallel magnetic resonance imaging(MRI)reconstruction model by utilizing the sensitivity information of receiver coils to achieve image reconstruction.The existing SENSE-based reconstruction algorithms usually used nonadaptive sparsifying transforms,resulting in a limited reconstruction accuracy.Therefore,we proposed a new model for accurate parallel MRI reconstruction by combining the L0 norm regularization term based on the efficient sum of outer products dictionary learning(SOUPDIL)with the SENSE model,called SOUPDIL-SENSE.The SOUPDIL-SENSE model is mainly solved by utilizing the variable splitting and alternating direction method of multipliers techniques.The experimental results on four human datasets show that the proposed algorithm effectively promotes the image sparsity,eliminates the noise and artifacts of the reconstructed images,and improves the reconstruction accuracy. 展开更多
关键词 parallel magnetic resonance imaging(MRI) sensitivity encoding(SENSE) efficient sum of outer products dictionary learning(SOUPDIL) alternating direction method of multipliers
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RELEASE KINETICS OF MONOLITHIC MATRIX COATED WITH OUTER MEMBRANE SYSTEM 被引量:1
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作者 石巍 张国亮 +1 位作者 张凤宝 刘瑛 《Transactions of Tianjin University》 EI CAS 2001年第1期56-60,共5页
The reservoir-monolithic type of the controlled release systems is investigated currently,however,the existing kinetic model could not describe the release process well because the release kinetics is rather complicat... The reservoir-monolithic type of the controlled release systems is investigated currently,however,the existing kinetic model could not describe the release process well because the release kinetics is rather complicated.In this paper,a simplified release kinetic model for diffusion-controlled monolithic matrix coated with outer membrane systems is proposed and verified by the experimental data of mercaptopurinum release experiment.It shows that the model can well describe the release mechanism (the relative error is under 3%) when drug loading (C d) is above its solubility limit (C s).At the same time,the release characteristics of special cases (D mD f and D mD f) are discussed theoretically.When D mD f the release rate becomes constant,namely,zero order release,and the release rate is independent of the drug membrane.This result provides the theoretical basis for the system of zero order release as well as how to control the release rate and the amount of drug release.When D mD f,the release rate is dependent on the drug release coefficient in the monolithic matrix,solubility and drug loading but independent of the process in the outer membrane,and it is similar to monolithic matrix type. 展开更多
关键词 controlled release DIFFUSION mercaptopurinum monolithic matrix outer membrane
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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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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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A356铝合金衬套外管挤压铸造工艺研究
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作者 刘亚刚 胡奖品 +5 位作者 吴晓成 彭文飞 冯光明 邵熠羽 张福鑫 高英豪 《精密成形工程》 北大核心 2026年第1期46-56,共11页
目的解决传统锻造成形工艺(生产效率低、后续加工量大、成本高)和低压铸造成形工艺(压力不足、成形缺陷多、力学性能差)在铝合金衬套外管制造中的技术瓶颈,提出挤压铸造成形新方法。方法基于ProCAST数值模拟与挤压铸造实验平台,研究不... 目的解决传统锻造成形工艺(生产效率低、后续加工量大、成本高)和低压铸造成形工艺(压力不足、成形缺陷多、力学性能差)在铝合金衬套外管制造中的技术瓶颈,提出挤压铸造成形新方法。方法基于ProCAST数值模拟与挤压铸造实验平台,研究不同挤压速度对A356铝合金衬套外管成形质量的影响,结合扫描电镜及力学性能测试,揭示工艺参数-微观组织-宏观性能的关联机制。结果当挤压速度为0.4 m/s时,铸件内部有缩松缩孔,且经过T6热处理后,缩松缩孔位置出现鼓包,此时屈服强度为231.59 MPa,抗拉强度为280.68 MPa,延伸率为4%。当挤压速度降低至0.3 m/s时,铸件内部缩松缩孔基本消失,屈服强度达到255.89 MPa,抗拉强度达到327.91 MPa,延伸率达到13.6%,较0.4 m/s工况下分别提升了10.5%、16.8%和2.4倍,并达到屈服强度≥250 MPa、抗拉强度≥310 MPa、延伸率≥9%的力学性能要求。微观组织显示,与挤压速度0.4 m/s相比,0.3 m/s工况下α-Al基体晶粒尺寸更小,且分布更为均匀细化,Al-Si共晶相更细化且分布更均匀,韧窝密度更大,而0.4 m/s工况存在粗大Al-Si相和孔洞缺陷,会因为Al-Si相的不均匀分布以及孔洞分布而更容易产生应力集中和裂纹扩展现象。工艺优化后,综合合格率达97.5%。结论挤压速度0.3 m/s可显著提升衬套外管的成形质量与力学性能,其强化机制归因于细晶强化与缺陷抑制的协同作用,优化后的工艺满足工程应用需求,为高强铝合金复杂构件成形提供了新策略。 展开更多
关键词 衬套外管 挤压铸造 A356铝合金 挤压速度 数值模拟
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一种变载荷工况下的深沟球轴承外圈故障动力学模型
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作者 李甲历 张凯 +1 位作者 张义民 欧旭鹏 《机械设计与制造》 北大核心 2026年第1期20-24,29,共6页
为了探究变载荷工况下具有外圈局部裂纹故障的深沟球轴承的运动特征,运用牛顿第二运动定律以及赫兹接触理论建立了一种深沟球轴承外圈局部故障的非线性四自由度动力学模型。该模型计算了滚动体与内外圈的接触变形,并综合考虑了油膜厚度... 为了探究变载荷工况下具有外圈局部裂纹故障的深沟球轴承的运动特征,运用牛顿第二运动定律以及赫兹接触理论建立了一种深沟球轴承外圈局部故障的非线性四自由度动力学模型。该模型计算了滚动体与内外圈的接触变形,并综合考虑了油膜厚度、滚动体滑动及轴系的重力等因素。通过对所建立外圈故障的深沟球轴承动力学模型进行求解,并运用快速傅里叶变换得到仿真信号的频谱,发现特征频率的高次谐波成分较为明显,且与原模型相比,所建立的动力学模型精度更高。与实验得到的振动数据的频谱进行对比后,验证了所建立模型的准确性,为滚动轴承的故障机理研究与故障诊断提供了参考。 展开更多
关键词 深沟球轴承 变载荷 动力学模型 非线性 四自由度 外圈故障
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特高压GIS套管内绝缘失效地震易损性分析
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作者 石高扬 谢强 《工程力学》 北大核心 2026年第1期260-268,共9页
特高压套管外套筒-导电杆体系在地震作用下存在电气功能失效的风险。为了研究导电杆位移引起的套管内绝缘失效,建立外套筒-导电杆耦联体系理论模型,利用±1100 kV复合材料GIS套管振动台试验和有限元分析进行模型验证,研究外套筒-导... 特高压套管外套筒-导电杆体系在地震作用下存在电气功能失效的风险。为了研究导电杆位移引起的套管内绝缘失效,建立外套筒-导电杆耦联体系理论模型,利用±1100 kV复合材料GIS套管振动台试验和有限元分析进行模型验证,研究外套筒-导电杆相互作用机理及地震易损性,结果表明:地震作用下套管内绝缘失效模式主要来源于:外套筒顶部位移引起的导电杆变形、导电杆自身受到的地震激励,其中外套筒顶部位移是引起内绝缘失效的主要原因;外套筒与导电杆的相对位移沿着高度呈现出近似抛物线分布规律,最大值点位于套管重心下部;相同地震强度作用下,特高压套管内绝缘失效概率介于套管根部断裂和顶部牵拉失效概率之间。外套筒-导电杆体系相对位移的地震响应可以通过建立耦联体系理论模型求得,应该同时关注内绝缘失效和套管根部断裂失效对电气功能的影响。 展开更多
关键词 特高压GIS套管 振动台试验 内绝缘失效 外套筒-导电杆体系 分析方法
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Study on Outer Membrane Protein Patterns of Escherichia coli O38,O53 and O75 Isolated from Chickens
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作者 张艳英 高桂生 +5 位作者 高光平 史秋梅 刘玉芹 张海莹 房海 陈翠珍 《Agricultural Science & Technology》 CAS 2012年第10期2070-2072,2122,共4页
[Objective] This study aimed to investigate the outer membrane protein (OMP) patterns of Escherichia coli 038, 053 and 075 isolates from chickens. [Method] Eight pathogenic E. coil isolates with various serotypes we... [Objective] This study aimed to investigate the outer membrane protein (OMP) patterns of Escherichia coli 038, 053 and 075 isolates from chickens. [Method] Eight pathogenic E. coil isolates with various serotypes were used as experimental materials to extract OMP by using supersonic schizolysis method and Sarcosyl. After SDS-PAGE electrophoresis, OMP patterns of the extracted products were determined based on the OMP model diagram. [Result] OMP of eight E. coil isolates with three serotypes were divided into three patterns, to be specific, 2 075 isolates respectively belonged to OMP-I and OMP-II pattern, 1 053 isolate belonged to OMP-II pattern, and 5 038 isolates belonged to OMP-I and OMP-III pattern. [Conclusion] Experimental results showed that E. coli isolates with the same serotype may belong to completely different OMP patterns, while serologically unrelated isolates may belong to the same OMP pattern. OMP of E. coil isolates with the same serotype may generate genetic differentiation; in addition, OMP of E. coli isolates with different serotypes may have different genetic correlation. 展开更多
关键词 Escherichia coli from chickens outer membrane protein pattern SDS- PAGE
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Prokaryotic Expression and Identification of Outer Membrane Protein 2 of Chlamydia trachomatis
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作者 陈超群 吴移谋 +2 位作者 李忠玉 朱翠明 尹卫国 《Chinese Journal of Sexually Transmitted Infections》 2004年第2期67-71,i001,共6页
Objective: To construct a recombinant plasmid containing the outer membrane protein 2 (Omp2) gene of Chlamydia trachomatis and express Omp2 in E.coli. Methods: The omp2 gene of C. trachomatis serovar D was cloned into... Objective: To construct a recombinant plasmid containing the outer membrane protein 2 (Omp2) gene of Chlamydia trachomatis and express Omp2 in E.coli. Methods: The omp2 gene of C. trachomatis serovar D was cloned into pQE30 vector following PCR amplification from genomic DNA. E. coli M15 transformants were induced to express the fusion protein by IPTG and the product was identified by SDS-PAGE and Western blot. Results: Confirmed by enzyme cleavage analysis and DNA sequencing, a correct recombinant plasmid pQE30/omp2 was constructed. The fusion protein from the transformants was approximately 60 kDa in size in SDS-PAGE analysis, which could specially react with anti-6 X His mouse monoclonal IgG antibodies. Conclusion: We successfully expressed Omp2 in E. coli M15, providing an efficient and simple system for assaying the immunological properties of Omp2. 展开更多
关键词 Chlamydia trachomatis outer membrane protein 2(omp2) expression.
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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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汽车发动机罩外板冲压开裂分析及工艺优化
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作者 何宁 张春华 +2 位作者 李丽坤 阳学 申丹凤 《锻压技术》 北大核心 2026年第1期179-186,共8页
针对某车型发动机罩外板冲压开裂问题,采用AutoForm冲压成形有限元软件分析了摩擦因数以及压边力等因素对成形效果的影响;结合现场实际测量数据,分析了模具间隙对管理面开裂的影响规律。结果表明,仿真分析中随着摩擦因数的减小发动机罩... 针对某车型发动机罩外板冲压开裂问题,采用AutoForm冲压成形有限元软件分析了摩擦因数以及压边力等因素对成形效果的影响;结合现场实际测量数据,分析了模具间隙对管理面开裂的影响规律。结果表明,仿真分析中随着摩擦因数的减小发动机罩外板A面的减薄率减小,而管理面位置越锁不住板料,进而导致减薄率增大;压边力较小时,模具压不住板料,当压边力大于2000 kN时,成形比较稳定,管理面开裂风险降低;凹模和压边圈的模具间隙增大,成形阻力减小,板料无法被有效锁住而发生流动,导致管理面减薄风险变高。优化方案中调整了凹模和压边圈的模具间隙:管理面的强压量增加至0.3 mm,拉延筋高度增加至8.5 mm,宽度加宽1 mm,同时拉延筋槽侧壁间隙减小0.05 mm。优化方案增加了材料流动阻力,从而使材料变形更加均匀。经过试验验证,该方案能有效解决管理面开裂问题。 展开更多
关键词 发动机罩外板 冲压开裂 摩擦因数 压边力 模具间隙
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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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