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Research on the mechanism of the two-dimensional ultrasonic surface burnishing process to enhance the wear resistance for aluminum alloy

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Friction 2024年第3期12卷 490-509页

作者： zhen-yu ZHOU Qiu-yang zhenG yu LI Cong DING Guang-Jian PENG Zhong-yu PIAO College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310014China

The gradient nanostructure is machined on the aluminum(Al)alloy by the two-dimensional ultrasonic surface burnishing process(2D-USBP).The mechanism of why the gradient nanostructure enhances wear resistance is investigated.The mechanical properties and microstructure characterization for the gradient nanostructure are performed by operating a nanoindenter,transmission electron microscopy(TEM),and electron backscattered diffraction(EBSD).Dry wear tests are performed on the samples before and after machining to evaluate the wear resistance and mechanisms.The effect of the gradient nanostructure on the wear resistance is explored by developing the crystal plasticity(CP)finite element and molecular dynamics(MD)models.The characterization results show that the 2D-USBP sample prepared a gradient structure of~600μm thick on the aluminum surface,increasing the surface hardness from 1.13 to 1.71 GPa and reducing the elastic modulus from 78.84 to 70.14 GPa.The optimization of the surface microstructure and the increase of the mechanical properties effectively enhance the wear resistance of the sample,with 41.20%,39.07%,and 54.58% of the wear scar areas for the 2D-USBP treated samples to the original samples under 5,10,and 15 N loads,respectively.The gradient nanostructure hinders the slip of dislocations inside the sample during the wear process and reduces the size and scope of plastic deformation;meanwhile,the resistance to deformation,adhesion,and crack initiation and propagation of the sample surface is improved,resulting in enhanced wear resistance.

关键词： structural superlubricity lattice registry elastic deformation strained solitons crystal plasticity molecular dynamics simulations

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Extraordinary hot extreme in summer 2022 over the yangtze River basin modulated by the La Nina condition under global warming

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Advances in Climate Change Research 2024年第1期15卷 21-30页

作者： zhen LIAO yu-Feng yuAN yang CHEN Pan-Mao ZHAI State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

A widespread and prolonged hot extreme hit the yangtze River basin in summer 2022,with 300 sites established new temperature records and nearly 96%stations endured more than 40 hot days.From the perspective of the combination effect of the global warming and La Nina condition,potential mechanisms of the hot extreme were investigated.Such a record-breaking hot extreme was caused by an extremely strong and westward-shifted western Pacific subtropical high(WPSH).The global warming effect contributed primarily to the abnormal hot days in the yangtze River basin,coupled with the modulation of the La Nina condition.The sea surface temperature anomaly pattern under La Nina condition favored more convection activities over the western Pacific,encouraging an enhanced and westward-extended WPSH.In addition,an observation-based attribution analysis indicates that anthropogenic warming may increase the probability of such extensively persistent hot extremeby1.8 times.

关键词： Hot extreme The yangtze River basin Global warming Tropical Pacific forcing

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Association between Gene Polymorphisms and SNP-SNP Interactions of the Matrix Metalloproteinase 2 Signaling Pathway and the Risk of Vascular Senescence

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Biomedical and Environmental Sciences 2024年第2期37卷 146-156页

作者： LIAO zhen yu yang Shuo HU Song LIU Jia MAO Yong Jun SUN Shu Qin Department of Geriatrics the Affiliated Hospital of Qingdao UniversityQingdao 266000ShandongChina Department of Critical Care Medicine the Affiliated Hospital of Qingdao UniversityQingdao 266000ShandongChina

Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.

关键词： Vascular senescence Pulse wave velocity(PWV) Single nucleotide polymorphism(SNP) Matrix metalloproteinase 2(MMP-2) Extracellular matrix(ECM) Structural degradation Multifactor dimensionality reduction(MDR)

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Carrimycin in the treatment of acute promyelocytic leukemia combined with pulmonary tuberculosis: A case report

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World Journal of Clinical Cases 2024年第3期12卷 623-629页

作者： Fu-yu yang Lei Shao Jie Su zhen-Meng Zhang Department of Infectious Diseases The Affiliated Central Hospital of Shandong First Medical UniversityJinan 250013Shandong ProvinceChina

BACKGROUND Pulmonary tuberculosis(PTB)is prevalent in immunocompromised populations,including patients with hematologic malignancies,human immunodeficiency virus infections,and chronic diseases.Effective treatment for acute promyelocytic leukemia(APL)combined with PTB is lacking.These patients show an extremely poor prognosis.Therefore,studies should establish efficient treatment options to improve patient survival and prognosis.CASE SUMMARY A 60-year-old male with pain in the right side of his chest and a fever for 4 d visited the outpatient department of our hospital.Peripheral blood smear revealed 54%blasts.Following bone marrow examinations,variant APL with TNRC18-RARA fusion gene was diagnosed.Chest computed tomography scan showed bilateral pneumonitis with bilateral pleural effusions,partial atelectasis in the lower lobes of both lungs,and the bronchoalveolar lavage fluid gene X-Pert test was positive,indicative of PTB.Carrimycin,ethambutol(EMB),and isoniazid(INH)were administered since he could not receive chemotherapy as the WBC count decreased continuously.After one week of treatment with carrimycin,the patient recovered from fever and received chemotherapy.Chemotherapy was very effective and his white blood cells counts got back to normal.After being given five months with rifampin,EMB and INH and chemotherapy,the patient showed complete remission from pneumonia and APL.CONCLUSION We report a case of PTB treated successfully with carrimycin with APL that requires chemotherapy.

关键词： Carrimycin Hematologic disease Acute myeloid leukemia Acute promyelocytic leukemia Pulmonary tuberculosis Case report

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Source apportionment of PM_(2.5)using PMF combined online bulk and single-particle measurements:Contribution of fireworks and biomass burning

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Journal of Environmental Sciences 2024年第2期136卷 325-336页

作者： Yanjing Zhang Wenshuai Li Lei Li Mei Li zhen Zhou Jianzhen yu yang Zhou Frontier Science Center for Deep Ocean Multispheres and Earth System(FDOMES)and Physical Oceanography Laboratory Ocean University of ChinaQingdaoShandong 266100China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdaoShandong 266100China Institute of Atmospheric Environment Safety and Pollution Control Jinan UniversityGuangdong 510632China Institute of Environment Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Department of Chemistry Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Division of Environment The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

Fireworks(FW)could significantly worsen air quality in short term during celebrations.Due to similar tracers with biomass burning(BB),the fast and precise qualification of FW and BB is still challenging.In this study,online bulk and single-particle measurements were combined to investigate the contributions of FW and BB to the overall mass concentrations of PM_(2.5)and specific chemical species by positive matrix factorization(PMF)during the Chinese New Year in Hong Kong in February 2013.With combined information,fresh/aged FW(abundant ^(140)K_(2)NO_(3)^(+)and ^(213)K_(3)SO_(4)^(+)formed from ^(113)K_(2)Cl^(+)discharged by fresh FW)can be extracted from the fresh/aged BB sources,in addition to the Second Aerosol,Vehicles+Road Dust,and Sea Salt factors.The contributions of FW and BB were investigated during three high particle matter episodes influenced by the pollution transported from the Pearl River Delta region.The fresh BB/FW contributed 39.2%and 19.6%to PM_(2.5)during the Lunar Chinese New Year case.However,the contributions of aged FW/BB enhanced in the last two episodes due to the aging process,evidenced by high contributions from secondary aerosols.Generally,the fresh BB/FW showed more significant contributions to nitrate(35.1%and15.0%,respectively)compared with sulfate(25.1%and 5.9%,respectively)and OC(14.8%and11.1%,respectively)on average.In comparison,the aged FW contributed more to sulfate(13.4%).Overall,combining online bulk and single-particle measurement data can combine both instruments’advantages and provide a new perspective for applying source apportionment of aerosols using PMF.

关键词： Source apportionment PMF Online bulk measurements Single particle analysis Fireworks Biomass burning

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Enhanced red luminescence of Ca_(3)Si_(2−x)M_(x)O_(7):Eu^(3+)(M=Al,P)phosphors via partial substitution of Si^(4+) for applications in white light-emitting diodes

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Rare Metals 2024年第2期43卷 736-748页

作者： yu-Hao Ma Xi Gao Wen-Tao Zhang zhen-Rui yang Zhou Zhao Chen Qu College of Materials and Chemistry and Chemical Engineering Chengdu University of TechnologyChengdu610059China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China International Advanced Energy Science Research and Education Center Graduate School of Energy ScienceKyoto UniversityYoshida-HonmachiKyoto606-8501Japan

A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.

关键词： Ca_(3)Si_(2)O_(7) Red-emitting phosphor Structure substitution Luminescence enhancement Crystal-field effect White light-emitting diode

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Crossed renal ectopia with rectal cancer:A case report

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World Journal of Clinical Cases 2024年第12期12卷 2122-2127页

作者： zhen-Wei Tang Hui-Feng yang Zhao-yu Wu Chang-You Wang Department of General Surgery North China University of Science and Technology Affiliated HospitalTangshan 063000Hebei ProvinceChina

BACKGROUND Crossed renal ectopia(CRE)occurs when one kidney crosses the midline from the primary side to the contralateral side while the ureter remains on the primary side.Rectal cancer,one of the most common malignant tumors of the digestive tract,refers to cancer from the dentate line to the rectosigmoid junction.The concurrent presentation of CRE alongside rectal cancer is an uncommon clinical observation.CASE SUMMARY Herein,we report a 69-year-old male patient with rectal cancer who was diagnosed with CRE via computed tomography during hospitalization.Following thorough preoperative evaluations,the patient underwent Dixon surgery.CONCLUSION We performed laparoscopic radical resection of rectal cancer and adequate lymph node removal in a patient with CRE with no postoperative discomfort.

关键词： Rectal cancer Crossed renal ectopia Anatomy Laparoscopic surgery Case report

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Design and Cryogenic Performance of a Hexapod Platform for a Large Ground-based Wide Field Survey Telescope

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Research in Astronomy and Astrophysics 2024年第1期24卷 178-187页

作者： yang yu Xue-Wen Wang yu Zhang Jia-Lin Sun zhen-Bang Xu Jian-Li Wang Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Chinese Academy of Sciences Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun 130033China University of Chinese Academy of Sciences Beijing 100049China

The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(as a corrector) is investigated in this paper. First, a ground-based telescope with 2.5 m aperture and 3.5 deg field of view is described. The telescope is under construction, and it is expected to be finished in 2023. Second, the hexapod platform with flexure hinges utilized to adjust the primary focus unit is proposed, which is applied as a corrector.Then, the inverse kinematics of the platform is established and an open-loop control system is built based on it.Finally, the cryogenic performance test for the hexapod platform is performed. The experimental results show that the resolution and repeatability of the translation for the hexapod platform can be achieved at the micrometer level.The resolution and repeatability of the rotation can be achieved at the arc-second level. Therefore, the cryogenic performance of the hexapod platform can meet the optical imaging requirements of the wide-field ground-based telescope. The kinematic analysis and cryogenic performance tests in the paper provide a technical reference for the precise alignment of the primary focus unit and the primary mirror, which can improve the imaging quality of the telescope.

关键词： methods:miscellaneous space vehicles:instruments telescopes miscellaneous

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Recent progress in self-propelled particles

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Journal of Hydrodynamics 2024年第1期36卷 61-77页

作者： zhen-yu Ouyang Jian-zhong Lin Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo315201China Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou310027China

Self-propelled particles are commonly found in a large number of planktonic organisms such as bacteria,fungi,and algae in nature,and researchers have taken a long interest in exploring their swimming mechanisms for more than a century.Especially in the past 20 years,with the development of computational fluid dynamics and flow display technology,as well as the need for the design of synthetic self-propelled particles and micro-swimming devices,self-propelled particles have become the forefront and hotspot of current research in the field of fluid mechanics.This paper first introduces the swimming characteristics of common self-propelled particles,leading to a classic“squirmer”type self-propelled particle model.On this basis,a systematic introduction and summary of the theoretical and numerical simulation research of“squirmer”will be conducted.Finally,the main challenges and opportunities faced by the current research will be summarized.

关键词： Self-propelled particles multiphase flow hydrodynamic interaction

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Doping engineering of iron oxide nanoparticles towards high performance and biocompatible T_(1)-weighted MRI contrast agents

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Rare Metals 2024年第1期43卷 298-308页

作者： Xue Xu Ping-Li Dong yu-yun Chai Run yang zhen-Hui Ma Chi-Chong Lu Department of Chemistry College of Chemistry and Materials EngineeringBeijing Technology and Business UniversityBeijing 100048China Department of Physics Beijing Technology and Business UniversityBeijing 100048China

Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast agents.Especially when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor tissue.Substitution doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed atoms.However,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and sizes.Here,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal decomposition.Then,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding affinity.Gd_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)imaging.This stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.

关键词： Iron oxide nanoparticles Small size Magnetic resonance imaging Substitutional doping Gd dopant

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