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Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song Zhang Chen-jun Yang Xiao-qian dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

Three‑dimensional numerical simulation of dynamic strength and failure mode of a rock mass with cross joints

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International Journal of Coal Science & Technology 2024年第2期11卷 35-52页

作者： Tingting Liu Wenxu Huang Chang Xiang qian dong Xinping Li Chao Zhang Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan 430056China School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan 430070China Hainan Institute Wuhan University of TechnologySanya 572025China

To study the dynamic mechanical properties and failure characteristics of intersecting jointed rock masses with different joint distributions under confining pressure,considering the cross angleαand joint persistence ratioη,a numerical model of the biaxial Hopkinson bar test system was established using the finite element method–discrete-element model coupling *** validity of the model was verified by comparing and analyzing it in conjunction with laboratory test ***-static combined impact tests were conducted on specimens under various conditions to investigate the strength characteristics and patterns of crack initiation and *** study revealed the predominant factors influencing intersecting joints with different angles and penetrations under impact *** results show that the peak stress of the specimens decreases first and then increases with the increase of the cross ***α<60°,regardless of the value ofη,the dynamic stress of the specimens is controlled by the main ***α≥60°,the peak stress borne by the specimens decreases with increasingη.Whenα<60°,the initiation and propagation of cracks in the cross-jointed specimens are mainly controlled by the main joint,and the final failure surface of the specimens is composed of the main joint and wing ***α≥60°orη≥0.67,the secondary joint guides the expansion of the wing cracks,and multiple failure surfaces composed of main and secondary joints,wing cracks,and co-planar cracks are *** lateral confinement significantly increases the dynamic peak stress able to be borne by the *** triaxial conditions,the degree of failure of the intersecting jointed specimens is much lower than that under uniaxial and biaxial conditions.

关键词： Cross joints Joint distribution form Dynamic failure characteristics FEM–DEM BHPB

Effect of tungsten carbide particles on microstructure and mechanical properties of Cu alloy composite bit matrix

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Journal of Iron and Steel Research International 2024年第2期31卷 519-530页

作者： Ding-qian dong Feng-yuan He Xin-hui Chen Hui Li Kai-hua Shi Hui-wen Xiong Xin Xiang Li Zhang College of Mechanical Engineering Sichuan University of Science and EngineeringZigong643000SichuanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083HunanChina Zigong Cemented Carbide Co. Ltd.Zigong643011SichuanChina Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Science and EngineeringZigong643000SichuanChina

Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration,using at least one of the three kinds of tungsten carbide particles,for example,irregular cast tungsten carbide,monocrystalline tungsten carbide and sintered reduced tungsten carbide *** effects of powder particle morphology,particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy,X-ray diffraction and abrasive wear test in *** results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy *** tungsten carbide partially dissolved in the copper alloy binding phase,and layers of Cu_(0.3)W_(0.5)Ni_(0.1)Mn_(0.1)C phase with a thickness of around 8–15μm were formed on the edge of the cast tungsten *** 45%irregular crushed fine cast tungsten carbide and 15%monocrystalline cast tungsten carbide were used as the skeleton,satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained,with the bending strength,impact toughness and hardness reaching 1048 MPa,4.95 J/cm^(2) and 43.6 HRC,*** main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn,and then peeled off from the matrix when further wear occurred.

关键词： Polycrystalline diamond compact Pressureless vacuum infiltration Copper alloy composite bit matrix Microstructure characterization Abrasive wear behavior

Yeats’s Ideals:Women Old and Young

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Journal of Literature and Art Studies 2024年第5期14卷 330-334页

作者： dong qian Beijing Foreign Studies University Beijing Information Science and Technology University BeijingChina

William Butler Yeats ranks among the most widely admired and intensively studied poets of the 20th *** paper intends to explore the women who have exerted the most critical influences upon Yeats,namely Gonne,Lady Gregory,and Georgie *** in Yeats’s poetry involved with symbolism,it is worth noting that his employment of symbols has used these women as the archetypes,and that the historical context rendered Yeats’s representations of them in his poetry all the more interesting.

关键词： ideals women representation symbolism occult

Correlation between abdominal computed tomography signs and postoperative prognosis for patients with colorectal cancer

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World Journal of Gastrointestinal Surgery 2024年第7期16卷 2145-2156页

作者： Shao-Min Yang Jie-Mei Liu Rui-Ping Wen Yu-dong qian Jing-Bo He Jing-Song Sun Department of Radiology Xingtan Hospital Affiliated to Shunde Hospital of Southern Medical UniversityFoshan 528315Guangdong ProvinceChina Department of Rehabilitation Medicine Shunde HospitalSouthern Medical UniversityFoshan 528399Guangdong ProvinceChina Department of Radiology Lecong Hospital of ShundeFoshan 528315Guangdong ProvinceChina Department of Ultrasound Lecong Hospital of ShundeFoshan 528315Guangdong ProvinceChina

BACKGROUND Patients with different stages of colorectal cancer(CRC)exhibit different abdominal computed tomography(CT)***,the influence of CT signs on CRC prognosis must be *** To observe abdominal CT signs in patients with CRC and analyze the correlation between the CT signs and postoperative *** The clinical history and CT imaging results of 88 patients with CRC who underwent radical surgery at Xingtan Hospital Affiliated to Shunde Hospital of Southern Medical University were retrospectively *** and multivariate Cox regression analyses were used to explore the independent risk factors for postoperative death in patients with *** three-year survival rate was analyzed using the Kaplan-Meier curve,and the correlation between postoperative survival time and abdominal CT signs in patients with CRC was analyzed using Spearman correlation *** For patients with CRC,the three-year survival rate was 73.86%.The death group exhibited more severe characteristics than the survival group.A multivariate Cox regression model analysis showed that body mass index(BMI),degree of periintestinal infiltration,tumor size,and lymph node CT value were independent factors influencing postoperative death(P<0.05 for all).Patients with characteristics typical to the death group had a low three-year survival rate(log-rankχ2=66.487,11.346,12.500,and 27.672,respectively,P<0.05 for all).The survival time of CRC patients was negatively correlated with BMI,degree of periintestinal infiltration,tumor size,lymph node CT value,mean tumor long-axis diameter,and mean tumor short-axis diameter(r=-0.559,0.679,-0.430,-0.585,-0.425,and-0.385,respectively,P<0.05 for all).BMI was positively correlated with the degree of periintestinal invasion,lymph node CT value,and mean tumor short-axis diameter(r=0.303,0.431,and 0.437,respectively,P<0.05 for all).CONCLUSION The degree of periintestinal infiltration,tumor size,and lymph node CT value are c

关键词： Colorectal cancer Abdominal Computed tomography signs Radical surgery Prognosis Correlation

朗华影片公司成立始末之考述(1924-1932)

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当代电影 2024年第6期 76-83页

作者：董茜青岛大学文学与新闻传播学院

在“进步叙事”的系统性遗忘及史述惯性的“遮蔽”下,对小型制片公司的史学研究长期处于“失焦”的窘况。本文从诺艾尔·伯奇的“断裂时刻”和媒介考古学理论视角出发,聚焦民族影业新旧转型期出现的朗华影片公司,对其兴发历程、出品考... 详细信息

在“进步叙事”的系统性遗忘及史述惯性的“遮蔽”下,对小型制片公司的史学研究长期处于“失焦”的窘况。本文从诺艾尔·伯奇的“断裂时刻”和媒介考古学理论视角出发,聚焦民族影业新旧转型期出现的朗华影片公司,对其兴发历程、出品考据和影人谱系等“存疑”问题进行史料考论及辨误。在“溯源”“脉流”之间建构朗华影片公司的深度历史形塑,探讨其作为裂变“碎片”的标本化意义,以期实现早期影史的一次补叙和新型史述路径探索。

关键词：朗华影片公司营业组织出品考据影人谱系史料考辨

Pectolinarin inhibited LPS-stimulated inflammation in microglial BV_(2) cells via NF-κB signaling pathway

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Traditional Medicine Research 2024年第6期9卷 12-18页

作者： Bin-Feng Cheng Xiao Feng Yu-qian dong Shao-Qin Jian Hao-Heng Yu Jing-Jing Li Ting Ma Jun Zhang Yao-dong Zhang Hai-Jie Yang Lei Wang Xinxiang Key Laboratory of Stress Cell Biology School of Life Sciences and TechnologyXinxiang Medical UniversityXinxiang 453003China Henan Neural Development Engineering Research Center Henan Children’s HospitalZhengzhou 410000China

Background:Neuro-inflammation is regarded as one of the critical pathogenesis in neurodegenerative diseases,which is characterized by the activated microglial ***(Pec),a natural flavonoid that exists in many Chinese herbal medicines,has been reported to have various biological ***,the effects and mechanisms on neuro-inflammation are not ***:In this study,the inhibitory effects and mechanisms of Pec on neuro-inflammation were investigated in the LPS-stimulated microglial BV_(2) ***_(2) microglial cells were treated with Pec or vehicle,followed by ***-linked immunosorbent assay,real-time quantitative PCR,nitric oxide and reactive oxygen species assay,and western blot were performed to examine the effects of Pec on neuro-inflammatory ***:We showed that Pec significantly inhibited the expression of tumor necrosis factorαand interleukin 6 in mRNA and protein levels induced by ***,the production of nitric oxide,iNOS,reactive oxygen species,and COX-2 were suppressed by Pec in LPS-stimulated microglial BV_(2) *** addition,Pec inhibited LPS-induced inflammation via nuclear factor kappa B signaling pathway,as evidenced by the reduction of the phosphorylation of inhibitor of nuclear factor kappa-B kinase,the degradation of IκBα,and the nuclear translocation of ***:Taken together,Pec exhibited anti-inflammatory effects in LPS-stimulated microglial BV_(2) cells via nuclear factor kappa B signaling pathway,which might provide therapeutic potential for neuro-inflammation and neurodegenerative diseases.

关键词： neuroinflammation microglial cells pectolinarin NF-κB

Small extracellular vesicles derived from human induced pluripotent stem cell-differentiated neural progenitor cells mitigate retinal ganglion cell degeneration in a mouse model of optic nerve injury

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Neural Regeneration Research 2025年第2期20卷 587-597页

作者： Tong Li Hui-Min Xing Hai-dong qian Qiao Gao Sheng-Lan Xu Hua Ma Zai-Long Chi State Key Laboratory of Ophthalmology Optometry and Visual ScienceEye HospitalWenzhou Medical UniversityWenzhouZhejiang ProvinceChina National Clinical Research Center for Ocular Diseases Eye HospitalWenzhou Medical UniversityWenzhouZhejiang ProvinceChina

Several studies have found that transplantation of neural progenitor cells(NPCs)promotes the survival of injured ***,a poor integration rate and high risk of tumorigenicity after cell transplantation limits their clinical *** extracellular vesicles(sEVs)contain bioactive molecules for neuronal protection and *** studies have shown that stem/progenitor cell-derived sEVs can promote neuronal survival and recovery of neurological function in neurodegenerative eye diseases and other eye *** this study,we intravitreally transplanted sEVs derived from human induced pluripotent stem cells(hiPSCs)and hiPSCs-differentiated NPCs(hiPSC-NPC)in a mouse model of optic nerve *** results show that these intravitreally injected sEVs were ingested by retinal cells,especially those localized in the ganglion cell *** with hiPSC-NPC-derived sEVs mitigated optic nerve crush-induced retinal ganglion cell degeneration,and regulated the retinal microenvironment by inhibiting excessive activation of *** analysis further revealed that hiPSC-NPC derived sEVs transported neuroprotective and anti-inflammatory miRNA cargos to target cells,which had protective effects on RGCs after optic nerve *** findings suggest that sEVs derived from hiPSC-NPC are a promising cell-free therapeutic strategy for optic neuropathy.

关键词： exosome miRNA neural progenitor cell neurodegeneration neuroinflammation neuroprotection optic nerve crush optic neuropathy retinal ganglion cell small extracellular vesicles

Computer-assisted three-dimensional individualized extreme liver resection for hepatoblastoma in proximity to the major liver vasculature

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World Journal of Gastrointestinal Surgery 2024年第4期16卷 1066-1077页

作者： Wen-Li Xiu Jie Liu Jing-Li Zhang Jing-Miao Wang Xue-Feng Wang Fei-Fei Wang Jie Mi Xi-Wei Hao NanXia qian dong Department of Pediatric Surgery The Affiliated Hospital of Qingdao UniversityQingdao 266000Shandong ProvinceChina Department of Pediatric Surgery Yijishan Hospital of Wannan Medical CollegeWuhu 241000Anhui ProvinceChina Shandong Provincial Key Laboratory of Digital Medicine and Computer-assisted Surgery Shandong College Collaborative Innovation Center of Digital Medicine Clinical Treatment and Nutrition HealthQingdao UniversityQingdao 266003Shandong ProvinceChina

BACKGROUND The management of hepatoblastoma(HB)becomes challenging when the tumor remains in close proximity to the major liver vasculature(PMV)even after a full course of neoadjuvant chemotherapy(NAC).In such cases,extreme liver resection can be considered a potential *** To explore whether computer-assisted three-dimensional individualized extreme liver resection is safe and feasible for children with HB who still have PMV after a full course of *** We retrospectively collected data from children with HB who underwent surgical resection at our center from June 2013 to June *** then analyzed the detailed clinical and three-dimensional characteristics of children with HB who still had PMV after a full course of *** Sixty-seven children diagnosed with HB underwent surgical *** age at diagnosis was 21.4±18.8 months,and 40 boys and 27 girls were ***-nine(88.1%)patients had a single tumor,39(58.2%)of which was located in the right lobe of the liver.A total of 47 patients(70.1%)had PRE-TEXT III or ***-nine patients(58.2%)underwent delayed *** a full course of NAC,16 patients still had close PMV(within 1 cm in two patients,touching in 11 patients,compressing in four patients,and showing tumor thrombus in three patients).There were 6 patients of tumors in the middle lobe of the liver,and four of those patients exhibited liver anatomy *** 16 children underwent extreme liver resection after comprehensive preoperative *** procedures were performed according to the preoperative plan,and the operations were successfully ***,the 3-year event-free survival of 67 children with HB is 88%.Among the 16 children who underwent extreme liver resection,three experienced recurrence,and one died due to multiple *** Extreme liver resection for HB that is still in close PMV after a full course of NAC is both safe and *** approach not only reduces th

关键词： Children Hepatoblastoma Surgery Three-dimensional Computer-assisted