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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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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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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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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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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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Analysis and optimization of stamping and forming process of bearing outer ring
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作者 Shichao Zhu Yulu Ding +4 位作者 Bing Long Hun Guo Linhan Ouyang Wengang Chen Zhengyi Jiang 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2024年第3期227-237,共11页
To address the common issues of wrinkling,tearing,and uneven wall thickness in the actual sheet metal stamp-ing process of the outer ring of needle roller bearings,this study analyzes critical technical indicators suc... To address the common issues of wrinkling,tearing,and uneven wall thickness in the actual sheet metal stamp-ing process of the outer ring of needle roller bearings,this study analyzes critical technical indicators such asforming limits,thickness distribution,and principal strains in the forming process in detail.Three-dimensionalmodels of the concave and convex dies were constructed.The effects of different process parameters,includingstamping speed,edge pressure,sheet metal thickness,and friction coefficient,on the quality of the forming partswere investigated by varying these parameters.Subsequently,the orthogonal experimental method was used todetermine an optimal experimental group from multiple sets of experiments.It was found that under the processparameters of a stamping speed of 3000 mm/s,edge pressure of 2000 N,sheet metal thickness of 0.9 mm,andfriction coefficient of 0.125,the forming quality of the outer ring of the bearing is ideal. 展开更多
关键词 Plate stamping Bearing outer ring Mold design OPTIMIZATION
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Improvement of the Birch Outer Bark Plywood Binder:The Impact of the Bark Fractional Composition and the Binder Preparation Methodology
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作者 Rūdolfs Bērziņš Aigars Pāže +3 位作者 Guntis Sosins Daniela Godiņa Laima Vēvere Jānis Rižikovs 《Journal of Renewable Materials》 EI CAS 2024年第12期2095-2113,共19页
Birch outer bark(BOB)from Betula pendula Roth.is a unique and valuable biomass feedstock that contains suberin.The biopolyester suberin is built from bifunctional fatty acids-suberinic acids(SA)-which can be obtained ... Birch outer bark(BOB)from Betula pendula Roth.is a unique and valuable biomass feedstock that contains suberin.The biopolyester suberin is built from bifunctional fatty acids-suberinic acids(SA)-which can be obtained through a depolymerization process in an alkaline medium and used as a binder due to their adhesive properties.The aim of this study was to develop the SA-containing binder and identify suitable pressing conditions to produce plywood that meets the shear strength requirements of the EN 314-2 standard 3rd moisture resistance class for bonding quality,ensuring durability in unprotected exterior conditions(shear strength≥1 N/mm^(2)).The raw BOB material was modified by extraction,milling,and fractionation,and the depolymerization methodology was enhanced by additional sieving to improve the adhesive properties of the obtained binders.Several analytical methods were used to characterize the feedstock and the binders.Higher heating value was used to assess the pure outer bark content of BOB.GC-MS and GPC were used to describe the monomeric and oligomeric composition of binders.TGA was used to describe the biopolymeric composition and DSC was used to determine the thermal behavior of the binders.As a result,successful modification of feedstock(extracted BOB,milled through 2 mm sieve,1-2 mm fraction used)and its depolymerization process(implementing the separation of coarse ligno-carbohydrate particles by 1 mm mesh sieve)was employed to obtain a binder for which suitable hot-pressing parameters were determined−200℃for 5 min at 1.8 MPa.Consequently,plywood with shear strength of 1.26±0.18 N/mm^(2),which adheres to the EN 314-2 standards 3rd moisture resistance class,was obtained. 展开更多
关键词 Birch outer bark DEPOLYMERIZATION suberinic acids BINDER PLYWOOD biomass feedstock renewable resources
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Recent advances in bacterial outer membrane vesicles:Effects on the immune system,mechanisms and their usage for tumor treatment
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作者 Shuo Xiang Qiufang Yao +1 位作者 Arshad Khan Dong Wang 《Journal of Pharmaceutical Analysis》 CSCD 2024年第12期1790-1801,共12页
Tumor treatment remains a significant medical challenge,with many traditional therapies causing notable side effects.Recent research has led to the development of immunotherapy,which offers numerous advantages.Bacteri... Tumor treatment remains a significant medical challenge,with many traditional therapies causing notable side effects.Recent research has led to the development of immunotherapy,which offers numerous advantages.Bacteria inherently possess motility,allowing them to preferentially colonize tumors and modulate the tumor immune microenvironment,thus influencing the efficacy of immunotherapy.Bacterial outer membrane vesicles(OMVs)secreted by gram-negative bacteria are nanoscale lipid bilayer structures rich in bacterial antigens,pathogen-associated molecular patterns(PAMPs),various proteins,and vesicle structures.These features allow OMVs to stimulate immune system activation,generate immune responses,and serve as efficient drug delivery vehicles.This dual capability enhances the effectiveness of immunotherapy combined with chemotherapy or phototherapy,thereby improving anticancer drug efficacy.Current research has concentrated on engineering OMVs to enhance production yield,minimize cytotoxicity,and improve the safety and efficacy of treatments.Consequently,OMVs hold great promise for applications in tumor immunotherapy,tumor vaccine development,and drug delivery.This article provides an overview of the structural composition and immune mechanisms of OMVs,details various OMVs modification strategies,and reviews the progress in using OMVs for tumor treatment and their anti-tumor mechanisms.Additionally,it discusses the challenges faced in translating OMV-based anti-tumor therapies into clinical practice,aiming to provide a comprehensive understanding of OMVs'potential for in-depth research and clinical application. 展开更多
关键词 Tumor treatment outer membrane vesicles IMMUNOTHERAPY Drug delivery
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Cooling and Optimization in the Groove of the Outer Rotor HubMotor
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作者 Zhuo Liu Yecui Yan 《Frontiers in Heat and Mass Transfer》 EI 2024年第5期1443-1460,共18页
The external rotor hub motor adopts direct drive mode,no deceleration drive device,and has a compact structure.Its axial size is smaller than that of a deceleration-driven hub motor,which greatly reduces the weight of... The external rotor hub motor adopts direct drive mode,no deceleration drive device,and has a compact structure.Its axial size is smaller than that of a deceleration-driven hub motor,which greatly reduces the weight of the vehicle and increases the cruising range of the vehicle.Because of the limited special working environment and performance requirements,the hub motor has a small internal space and a large heat generation,so it puts forward higher requirements for heat dissipation capacity.For the external rotor hub motor,a new type of in-tank watercooled structure of hub motor was proposed to improve its cooling effect and performance.Firstly,the threedimensional finite element model of the motor is established to analyze the characteristics of motor loss and temperature field distribution.Secondly,the cooling performance of different cooling structures in the tank was studied.Finally,the thermal network model and three-dimensional finite element analysis were used to optimize the water-cooled structure in the tank,and the power density of themotor was improved by improving the cooling performance under the condition of volume limitation of the hub motor.The results show that the cooling effect of the proposed water-cooled structure in the tank is significant under the condition of constant power density.Compared to natural ventilation,the maximum temperature was reduced by 33.13°C and the cooling effect was increased by about 27.7%. 展开更多
关键词 outer rotor hub motor temperature field water cooling in the tank motor loss thermal networks high torque density
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内置CFRP圆管的方钢管再生混凝土偏压短柱力学性能研究 被引量:1
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作者 许伟 程嘉宝 +1 位作者 佟舟 张海霞 《沈阳建筑大学学报(自然科学版)》 北大核心 2025年第1期39-46,共8页
研究外截面形式、受压类型和偏心率等变化参数对内置CFRP圆管的方钢管再生混凝土短柱力学性能的影响。利用ABAQUS有限元分析软件建立组合柱力学模型,在有限元模拟和轴压试验结果吻合的基础上,进一步研究试件的偏压力学性能。增加CFRP层... 研究外截面形式、受压类型和偏心率等变化参数对内置CFRP圆管的方钢管再生混凝土短柱力学性能的影响。利用ABAQUS有限元分析软件建立组合柱力学模型,在有限元模拟和轴压试验结果吻合的基础上,进一步研究试件的偏压力学性能。增加CFRP层数,对轴压试件的极限承载力和位移延性系数提高幅度可分别达到30.44%、41.11%,对偏压试件的极限承载力和位移延性系数提高幅度分别为5.97%、37.49%;增加偏心率,对方截面试件的极限承载力和位移延性系数降低幅度分别达到41.22%、20.16%,对圆截面试件的极限承载力和位移延性系数降低幅度分别为45.79%、33.02%。内置CFRP圆管能够改善方钢管再生混凝土短柱的力学性能,但对偏压柱的影响小于轴压柱;在模拟参数范围内,随着偏心率的增加,试件力学性能降低;但同等截面面积下,方截面试件的偏压力学性能比圆截面试件的偏压力学性能更稳定。 展开更多
关键词 CFRP层数 偏心率 受压类型 外截面形式
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革兰氏阴性菌外膜囊泡的研究进展 被引量:1
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作者 倪秀梅 刘宇 刘开云 《生物工程学报》 北大核心 2025年第4期1221-1239,共19页
细菌膜囊泡(membrane vesicles,MVs)是细菌产生的非复制性球形纳米颗粒,其中由革兰氏阴性菌自发产生的囊泡被称为外膜囊泡(outer membrane vesicles,OMVs)。OMVs可以介导脂多糖、肽聚糖、蛋白质和核酸等生物分子在群体间进行物质交流,... 细菌膜囊泡(membrane vesicles,MVs)是细菌产生的非复制性球形纳米颗粒,其中由革兰氏阴性菌自发产生的囊泡被称为外膜囊泡(outer membrane vesicles,OMVs)。OMVs可以介导脂多糖、肽聚糖、蛋白质和核酸等生物分子在群体间进行物质交流,并发挥着不同的生理学功能。近年来,基于其独特的结构和功能,OMVs已被开发应用于疫苗、佐剂、药物递送载体和癌症免疫治疗剂等多种生物制品。本文综述了革兰氏阴性菌OMVs的产生途径、组成成分和生理学功能,归纳总结了近年来OMVs在应用开发、修饰改造以及制备鉴定等方面的研究进展,并对OMVs的未来研究方向提出展望,为拓展OMVs在生物医学领域的应用提供了参考。 展开更多
关键词 革兰氏阴性菌 外膜囊泡 生理学功能 生物医学应用 修饰改造
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外空军控治理“释法/造法”新维度与新路径
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作者 王国语 张泽辰 《国际安全研究》 北大核心 2025年第4期99-125,159,160,共29页
外空被视为大国博弈的制高点。相比硬实力比拼而言,外空军控规则博弈更为显性、直接和长效,因为军控规则往往意味着禁止或限制某类能力或行为。随着外空武器化和战场化风险日益增加,博弈各方对于有序博弈的诉求不断提升,航天大国对于具... 外空被视为大国博弈的制高点。相比硬实力比拼而言,外空军控规则博弈更为显性、直接和长效,因为军控规则往往意味着禁止或限制某类能力或行为。随着外空武器化和战场化风险日益增加,博弈各方对于有序博弈的诉求不断提升,航天大国对于具体军控规则的诉求整体趋同,但由于战略定位的不同也必然存在实质性分歧。2008年以来,相关方根据博弈需要,同时也是为了解决外空安全治理国际规则体系发展滞后的问题,各类外空军控倡议层出不穷,规则博弈日趋激烈复杂。大部分观点认为,外空军控已形成中俄主导的“硬法”与美西方主导的“软法”两种治理路径,阵营之争首先体现为路径之争。软法/硬法二分法治理维度已成为加剧大国外空博弈的政治工具和导致外空治理更加分裂的“伤害性力量”。各国被迫“选边站队”,形成了两大军控进程并行竞争的局面,外空军控谈判一度陷入僵局,对各方而言,这既是挑战,也是机遇。外空军控博弈的关键就在于谁能率先提出打破僵局的新维度和新路径,引领国际社会走向良性的外空安全治理,谁就将真正主导外空安全全球治理的话语权。 展开更多
关键词 外空软法 外空硬法 外空军控 外空安全全球治理 法律解释
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同步密封壳内外壁圆环凹槽复合脱模机构注塑模设计 被引量:2
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作者 张利华 《中国塑料》 北大核心 2025年第2期94-99,共6页
为同步密封壳塑件的注塑成型创新设计了一副多板式一模两腔潜伏式浇口两板模,采用分区分步进行脱模来实现塑件的自动化注塑生产。具体做法为:现将内壁的整圈圆环凹槽分解成4段,其中2段使用内收滑块实施抽芯脱模,剩余2段则使用2个“瓦片... 为同步密封壳塑件的注塑成型创新设计了一副多板式一模两腔潜伏式浇口两板模,采用分区分步进行脱模来实现塑件的自动化注塑生产。具体做法为:现将内壁的整圈圆环凹槽分解成4段,其中2段使用内收滑块实施抽芯脱模,剩余2段则使用2个“瓦片”形斜顶实施侧抽芯脱模,而外壁上的半圆环凹槽则使用2个定模侧哈夫滑块实施侧抽芯脱模,塑件最终由推板推出脱模。塑件的完全脱模由模具的5个动作来实现,包括3次开模动作和2次推出动作,其中第3次开模与2次顶出为同步动作。第1次开模使内收滑块实现内壁圆环凹槽的部分脱模,紧接着使外壁的哈夫滑块完成侧抽芯脱模,第2次为塑件从型腔镶件中脱出,第3次开模动作中,同时也包含2次顶出机构的2次顶出动作。第1次顶出为内壁剩余圆环凹槽使用2次顶出机构的1次顶出板推动斜顶顶出而实现,第2次为上推板将塑件从芯部成型件上推出而实现完全脱模。 展开更多
关键词 同步密封壳 外壁圆环凹槽 内壁圆环凹槽 哈夫滑块 内收滑块 斜顶 二次顶出
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某发动机罩外板网孔覆膜结构冲压工艺分析
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作者 裴永生 李亮亮 +2 位作者 李志明 刘选太 赵彩艳 《锻压技术》 北大核心 2025年第2期40-45,共6页
针对目前汽车发动机罩外板与行人碰撞时会对行人头部造成较大伤害的问题,分析了某发动机罩外板与行人头部碰撞概率较高的区域,对其进行了均布网孔设计,降低了其刚度,在一定程度上实现了对行人头部的保护。同时,考虑发动机罩外板外覆盖... 针对目前汽车发动机罩外板与行人碰撞时会对行人头部造成较大伤害的问题,分析了某发动机罩外板与行人头部碰撞概率较高的区域,对其进行了均布网孔设计,降低了其刚度,在一定程度上实现了对行人头部的保护。同时,考虑发动机罩外板外覆盖件密封的需求,利用橡胶薄膜对开孔部位进行粘贴,保证其实际使用需求。首先,利用金属板料拉伸性能试验确定网孔设计的初步方案;然后,对原实体板料的冲压模具的模面进行修改,使带孔板料冲压后产品满足设计要求;最后,使用Autoform软件进行回弹补偿与迭代优化,并利用Think-design软件对补偿后的工具体模面进行了曲面拟合,保证了带孔板料冲压后产品满足设计要求,以及最终产品可以满足其在检测工装上的精度要求。 展开更多
关键词 发动机罩外板 网孔覆膜 冲压工艺 回弹补偿 头部保护
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双向赋能:区域国别学视角下的外层空间国际战略研究 被引量:1
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作者 翟崑 高思成 《天津大学学报(社会科学版)》 2025年第1期45-52,共8页
我国外层空间国际战略研究面临客观需求迫切、有效供给匮乏的“研究赤字”。交叉学科门类下区域国别学一级学科的设立为加强外层空间国际战略研究带来了有益思路。区域国别学为外层空间国际战略研究的系统集成提供了新的条件,使后者主... 我国外层空间国际战略研究面临客观需求迫切、有效供给匮乏的“研究赤字”。交叉学科门类下区域国别学一级学科的设立为加强外层空间国际战略研究带来了有益思路。区域国别学为外层空间国际战略研究的系统集成提供了新的条件,使后者主体性得以彰显、交叉性得以实现、应用性得以提高、价值使命得以明确。外层空间国际战略研究亦可以促进区域国别学研究对象的扩展、研究方法的交叉、学科价值的实现,从而赋能区域国别学学科发展。外层空间国际战略研究作为一个研究领域,与区域国别学学科存在着显著的“双向赋能”关系。未来,建议在区域国别学框架下建立系统集成的外层空间国际战略研究议程。 展开更多
关键词 区域国别学 外层空间 国际战略 学科交叉 新文科
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频率等间隔的轴承故障信号模型及其希尔伯特共振解调机理
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作者 何国林 李俊晖 +3 位作者 李巍华 林慧斌 陈华原 许中生 《振动工程学报》 北大核心 2025年第6期1287-1295,共9页
希尔伯特共振解调技术(HRD)广泛应用于轴承故障诊断。在利用包络幅值谱评估降噪方法优劣时,可能会把HRD产生的影响归因于降噪方法。工程中测试条件与分析参数的选取通常依靠经验,选取不当易引发故障漏诊。针对这些问题,通过构建轴承外... 希尔伯特共振解调技术(HRD)广泛应用于轴承故障诊断。在利用包络幅值谱评估降噪方法优劣时,可能会把HRD产生的影响归因于降噪方法。工程中测试条件与分析参数的选取通常依靠经验,选取不当易引发故障漏诊。针对这些问题,通过构建轴承外圈故障振动响应的故障信号模型,定量分析故障信号的希尔伯特共振解调过程,揭示了信号参数与包络幅值谱的映射关系;通过分析固有频率、阻尼比和转速等系统物理参数对信号参数的影响,明确了系统物理参数与包络幅值谱分布的对应关系,为HRD的应用提供了更为明确的理论依据。利用HRD处理仿真振动信号,仿真结果与理论推导一致;并通过试验验证了基于HRD解调机理的分析结论。 展开更多
关键词 滚动轴承 外圈局部故障 希尔伯特变换 共振解调机理 故障信号模型
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基于起裂荷载确定软岩抗拉强度的试验验证
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作者 马春德 谭观霜 +2 位作者 张俊杰 赵俊康 阳文源 《中南大学学报(自然科学版)》 北大核心 2025年第4期1397-1404,共8页
针对圆环劈裂试验中基于峰值荷载导致岩石抗拉强度被高估的缺陷,对不同内外径比(0.2、0.3、0.4、0.5、0.6)的红砂岩圆环试样进行劈裂试验,利用3种手段(声发射、应变片及数字图像相关技术)捕捉拉伸裂纹起裂点,以期提高圆环劈裂试验测试... 针对圆环劈裂试验中基于峰值荷载导致岩石抗拉强度被高估的缺陷,对不同内外径比(0.2、0.3、0.4、0.5、0.6)的红砂岩圆环试样进行劈裂试验,利用3种手段(声发射、应变片及数字图像相关技术)捕捉拉伸裂纹起裂点,以期提高圆环劈裂试验测试岩石抗拉强度的准确性。同时,对红砂岩进行巴西劈裂及直接拉伸试验,验证圆环劈裂试验结果的准确性。研究结果表明:圆环起裂荷载随着内外径比增大而降低,当内外径比为0.5和0.6时,基于起裂荷载计算得到的抗拉强度接近直接拉伸强度(相对偏差最小仅为3.3%)。基于起裂点的圆环劈裂试验是测试软岩间接抗拉强度的可靠方法。 展开更多
关键词 抗拉强度 圆环劈裂试验 起裂荷载 内外径比
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