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Research on Abrasives in the Chemical Mechanical Polishing Process for Silicon Nitride Balls

厦门大学学报（自然科学版） 2002年第S1期41卷 63-64页

作者： yuan ju-long, lü bing-hai, lin xü, ji shi-ming, zhang li-bin (Mechanical and Electronic Engineering College, Zhejiang University of Technology, Hangzhou 310014, China)

Silicon nitride (Si 3N 4) has been the main material for balls in ceramic ball bearings, for its lower density, high strength, high hardness, fine thermal stability and anticorrosive, and is widely used in various fields, such as high speed and high temperature areojet engines, precision machine tools and chemical engineer machines. Silicon nitride ceramics is a kind of brittle and hard material that is difficult to machining. In the traditional finishing process of silicon nitride balls, balls are lapped by expensive diamond abrasive. The machining is inefficiency and the cost is high, but also lots of pits, scratch subsurface micro crazes and dislocations will be caused on the surface of the balls, the performance of the ball bearings would be declined seriously. In these year, a kind of new technology known as chemical mechanical polishing is introduced in the ultraprecision machining process of ceramic balls. In this technology, abrasives such as ZrO 2, CeO 2 whose hardness is close to or lower than the work material (Si 3N 4) are used to polishing the balls. In special slurry, these abrasives can chemo-mechanically react with the work material and environment (air or water) to generate softer material (SiO 2). And the resultants will be removed easily at 0.1 nm level. So the surface defects can be minimized, very smooth surface (Ra=4 nm) and fine sphericity (0.15～0.25 μm ) can be obtained, and the machining efficiency is also improved. The action mechanism of the abrasives in the chemical mechanical polishing process in finishing of silicon nitride ball will be introduced in this paper.

关键词： silicon nitride ball chemical mechanical polishing abrasives

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Spin Evolution of the Magnetar SGR J1935+2154

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Research in Astronomy and Astrophysics 2024年第1期24卷 201-211页

作者： ming-Yu Ge yuan-Pei Yang Fang-jun lu shi-Qi Zhou long ji Shuang-Nan zhang bing zhang liang zhang Pei Wang Kejia lee Weiwei Zhu jian li xian Hou Qiao-Chu li Key laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China South-Western Institute For Astronomy Research Yunnan UniversityKunming 650504China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China Key laboratory of Stellar and Interstellar Physics and School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China School of Physics and Astronomy Sun Yat-Sen UniversityZhuhai 519082China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Nevada Center for Astrophysics University of NevadaLas VegasNV 89154USA Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Department of Astronomy Peking UniversityBeijing 100871China CAS Key laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Yunnan Observatories Chinese Academy of SciencesKunming 650216China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Key laboratory of Modern Astronomy and Astrophysics Nanjing UniversityNanjing 210023China

Fast radio bursts(FRBs)are short pulses observed in radio frequencies usually originating from cosmological *** discovery of FRB 200428 and its x-ray counterpart from the Galactic magnetar SGR J1935+2154suggests that at least some FRBs can be generated by ***,the majority of x-ray bursts from magnetars are not associated with radio *** fact that only in rare cases can an FRB be generated raises the question regarding the special triggering mechanism of *** we report long time spin evolution of SGR J1935+2154 until the end of *** to v and v,the spin evolution of SGR J1935+2154 could be divided into two *** first stage evolves relatively steady evolution until 2020 April *** the burst activity in2020,the spin of SGR J1935+2154 shows strong variations,especially for *** the burst activity in 2022October,a new spin-down glitch with△v/v=(-7.2±0.6)×10^(-6)is detected around MJD 59876,which is the second event in SGR J1935+*** the end,spin frequency and pulse profile do not show variations around the time of FRB 200428 and radio bursts 221014 and 221021,which supply strong clues to constrain the trigger mechanism of FRBs or radio bursts.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(SGR J1935+2154) x-rays:bursts

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Synergistic effect of Zr and Mo on precipitation and high-temperature properties of Al-Si-Cu-Mg alloys

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China Foundry 2024年第1期21卷 71-81页

作者： Chao Gao bing-rong zhang Yin-ming li Zhi-ming Wang xiang-bin Meng Faculty of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Hebei Ounai Machinery Mould Co.ltd. Xingtai 054500HebeiChina

This study focuses on finding a solution to the sharp decline in mechanical properties of Al-Si-Cu-Mg alloys due to rapid coarsening of traditional intermediate phases at high temperature.A new type of modified al oy,to be used in automobile engines at high temperatures,was prepared by adding Zr and Mo into Al-Si-Cu-Mg *** synergistic effects of Zr and Mo on the microstructure evolution and high-temperature mechanical properties were *** show that the addition of Zr and Mo generates a series of intermetallic phases dispersed in the *** can improve the strength of the alloy by hindering dislocation movement and crack *** addition,some nano-strengthened phases show coherent interfaces with the matrix and improve grain *** addition of Mo greatly improves the heat resistance of the *** extremely low diffusivity of Mo enables it to improve the thermal stability of the intermetallic phases,inhibit precipitation during aging,reduce the size of the precipitates,and improve the heat resistance of the alloy.

关键词： Al-Si-Cu-Mg alloy high-temperature properties Zr-Mo-rich intermetallics nano-strengthening phases

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HepG2.2.15-derived exosomes facilitate the activation and fibrosis of hepatic stellate cells

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World Journal of Gastroenterology 2024年第19期30卷 2553-2563页

作者： Yang Gao li li Sheng-Ning zhang yuan-Yi Mang xi-bing zhang shi-ming Feng Department of Hepatobiliary Pancreatic and Vascular Surgery The Affiliated Calmette Hospital of Kunming Medical University and The First Hospital of KunmingKunming 650011Yunnan ProvinceChina

BACKGROUND The role of exosomes derived from HepG2.2.15 cells,which express hepatitis B virus(HBV)-related proteins,in triggering the activation of lx2 liver stellate cells and promoting liver fibrosis and cell proliferation remains *** focus was on comprehending the relationship and influence of differentially expressed microRNAs(DE-miRNAs)within these *** To elucidate the effect of exosomes derived from HepG2.2.15 cells on the activation of hepatic stellate cell(HSC)lx2 and the progression of liver *** Exosomes from HepG2.2.15 cells,which express HBV-related proteins,were isolated from parental HepG2 and WRl68 *** blotting was used to confirm the presence of the exosomal marker protein *** activation of HSCs was assessed using oil red staining,whereas DiI staining facilitated the observation of exosomal uptake by lx2 ***,we evaluated lx2 cell proliferation and fibrosis marker expression using 5-ethynyl-2′-deoxyuracil staining and western blotting,***-miRNAs were analyzed using *** Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways were used to annotate the target genes of *** Exosomes from HepG2.2.15 cells were found to induced activation and enhanced proliferation and fibrosis in lx2 cells.A total of 27 miRNAs were differentially expressed in exosomes from HepG2.2.15 *** analysis indicated that these DE-miRNA target genes were associated with cell differentiation,intracellular signal transduction,negative regulation of apoptosis,extracellular exosomes,and RNA *** pathway analysis highlighted ubiquitin-mediated proteolysis,the MAPK signaling pathway,viral carcinogenesis,and the toll-like receptor signaling pathway,among others,as enriched in these *** These findings suggest that exosomes from HepG2.2.15 cells play a substantial role in the activation,proliferation,and fibrosis of lx2 cells and that DE-miRNAs within these exos

关键词： Hepatic stellate cells liver fibrosis Exosomes Small RNA sequencing HepG2.2.15

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Metabolic landscape of head and neck squamous cell carcinoma informs a novel kynurenine/Siglec-15 axis in immune escape

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Cancer Communications 2024年第6期44卷 670-694页

作者： xin-Yu zhang jian-Bo shi Shu-Fang jin Rui-jie Wang ming-Yu li Zhi-yuan zhang xi Yang hai-long Ma Department of Oral Maxillofacial-Head and Neck Oncology Shanghai Ninth People’s HospitalCollege of StomatologyShanghai Jiao Tong University School of MedicineShanghaiP.R.China National Clinical Research Center for Oral Diseases ShanghaiP.R.China Shanghai Key laboratory of Stomatology&Shanghai Research Institute of Stomatology ShanghaiP.R.China Department of Second Dental Center Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineCollege of StomatologyShanghai Jiao Tong UniversityShanghaiP.R.China

Background:Metabolic reprograming and immune escape are two hallmarksof ***,how metabolic disorders drive immune escape in head andneck squamous cell carcinoma(HNSCC)remains ***,the aim ofthe present study was to investigate the metabolic landscape of HNSCC and itsmechanism of driving immune ***:Analysis of paired tumor tissues and adjacent normal tissues from69 HNSCC patients was performed using liquid/gas chromatography-mass spectrometry and *** tumor-promoting function of kynurenine(Kyn)was explored in vitro and in *** downstream target of Kyn wasinvestigated in CD8^(+)T *** regulation of CD8+T cells was investigatedafter Siglec-15 overexpression in *** engineering nanoparticle was establishedto deliver Siglec-15 small interfering RNA(siS15),and its association withimmunotherapy response were *** association between Siglec-15and CD8^(+)programmed cell death 1(PD-1)^(+)T cells was analyzed in a HNSCCpatient ***:A total of 178 metabolites showed significant dysregulation in HNSCC,including carbohydrates,lipids and lipid-like molecules,and amino *** these,amino acid metabolism was the most significantly altered,especiallyKyn,which promoted tumor proliferation and *** addition,most immune checkpoint molecules were upregulated in Kyn-high patientsbased on ***,tumor-derived Kyn was transferredinto CD8^(+)T cells and induced T cell functional exhaustion,and blockingKyn transporters restored its killing *** to the results,mechanistically,Kyn transcriptionally regulated the expression of Siglec-15 via arylhydrocarbon receptor(AhR),and overexpression of Siglec-15 promoted immuneescape by suppressing T cell infiltration and *** AhR in vivoreduced Kyn-mediated Siglec-15 expression and promoted intratumoral CD8^(+)Tcell infiltration and killing ***,a NH_(2)-modified mesoporous silicananoparticle was des

关键词： head and neck squamous cell carcinoma kynurenine Siglec-15 T cell exhaustion untargeted metabolomics

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Preparation and Rheological Characterization of long Chain Branching Polyglycolide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-lin liu ming-Fu lyu Heng-yuan zhang jian-Ye liu shi-jun zhang Beijing University of Chemical Technology Beijing 100029China SINOPEC(Beijing)Research Institute of Chemical Industry Co. Ltd.Beijing 100013China

The long chain branching(lCB)polyglycolide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of lCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher viscosity and the more notable strain hardening behavior of modified PGA indicates the lCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical CO_(2)foaming can be carried out successfully.

关键词： Polyglycolide(PGA) long chain branching(lCB) Rheology

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Construction and performance test of charged particle detector array for MATE

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Nuclear Science and Techniques 2024年第8期35卷 92-100页

作者： xiao‑bin li long‑Hui Ru Zhi‑Chao zhang bing‑Feng lv Ning‑Tao zhang jin‑long zhang Chen‑Gui lu bing‑Shui Gao jun‑bing Ma Fu‑Shuai shi Satoru Terashima xiao‑Dong xu Zhen Bai shi‑Wei xu Yan‑Yun Yang Hooi‑jin Ong xiao‑Dong Tang Institute of Modern Physics(IMP) Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Research Center for Nuclear Physics Osaka UniversityIbarakiOsaka 567‑0047Japan RIKEN Nishina Center WakoSaitama 351‑0198Japan Joint Department for Nuclear Physics Lanzhou University and Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China

A charged particle array named MATE-PA,which serves as an auxiliary detector system for a Multi-purpose Active-target Time projection chamber used in nuclear astrophysical and exotic beam Experiments(MATE),was *** array comprised of 20 single-sided strip-silicon detectors covering approximately 10%of the solid *** detectors facilitated the detection of reaction-induced charged particles that penetrate the active volume of the *** performance of MATE-PA has been experimentally studied using an alpha source and a 36-MeV 14 N beam injected into the MATE chamber on the radioactive ion beam line in lanzhou(RIBll).The chamber was filled with a gas mixture of 95%4 He and 5%CO_(2) at a pressure of 500 *** results indicated good separation of light-charged particles using the forward double-layer silicon detectors of *** energy resolution of the Si detectors was deduced to be approximately 1%(σ)for an energy loss of approximately 10 MeV caused by theα*** inclusion of MATE-PA improves particle identification and increases the dynamic range of the kinetic energy of charged particles,particularly that of theαparticles,up to approximately 15 MeV.

关键词： Silicon detector array Active target Time projection chamber

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Insight into the selective separation of CO_(2)from biomass pyrolysis gas over metal-incorporated nitrogen-doped carbon materials:a first-principles study

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 1-12页

作者： li Zhao xinru liu Zihao Ye bin Hu Haoyu Wang ji liu bing zhang Qiang lu National Engineering Research Center of New Energy Power Generation North China Electric Power UniversityBeijing102206China

The composition of biomass pyrolysis gas is complex,and the selective separation of its components is crucial for its further ***-incorporated nitrogen-doped materials exhibit enormous potential,whereas the relevant adsorption mechanism is still ***,16 metal-incorporated nitrogen-doped carbon materials were designed based on the density functional theory calculation,and the adsorption mechanism of pyrolysis gas components H2,CO,CO_(2),CH_(4),and C2H6 was *** results indicate that metal-incorporated nitrogen-doped carbon materials generally have better adsorption effects on CO and CO_(2)than on H_(2),CH_(4),and C_(2)H_(6).Transition metal Mo-and alkaline earth metal Mg-and Ca-incorporated nitrogen-doped carbon materials show the potential to separate CO and CO_(2).The mixed adsorption results of CO_(2)and CO further indicate that when the CO_(2)ratio is significantly higher than that of CO,the saturated adsorption of CO_(2)will precede that of ***,the three metal-incorporated nitrogen-doped carbon materials can selectively separate CO_(2),and the alkaline earth metal Mg-incorporated nitrogen-doped carbon material has the best *** study provides theoretical guidance for the design of carbon capture materials and lays the foundation for the efficient utilization of biomass pyrolysis gas.

关键词： CO_(2)capture biomass pyrolysis gas selective adsorption carbon materials first-principles

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Global Spherically Symmetric Solutions for a Coupled Compressible Navier–Stokes/Allen–Cahn System

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Acta Mathematica Sinica,English Series 2024年第8期40卷 2037-2064页

作者： Chang ming SONG jian lin zhang yuan yuan WANG Department of Applied Mathematics School of Mathematics and Information ScienceZhongyuan University of TechnologyZhengzhou 450007P.R.China

In this paper,we consider the global spherically symmetric solutions for the initial boundary value problem of a coupled compressible Navier–Stokes/Allen–Cahn system which describes the motion of two-phase viscous compressible *** prove the existence and uniqueness of global classical solution,weak solution and strong solution under the assumption of spherically symmetry condition for initial dataρ0 without vacuum state.

关键词： Diffuse interface model global solutions Navier-Stokes equations Allen-Cahn equation spherically symmetry

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Peroxisome Proliferator-Activated Receptor-γCoactivator-1αin the Spotlight with Multiple Sclerosis

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Neuroscience Bulletin 2024年第2期40卷 268-272页

作者： Ya-Na Yang Mao-Qing zhang Feng-lin Yu bing Han ming-Yue Bao Yan He xing li yuan zhang Key laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry(Shaanxi Normal University) The Ministry of EducationXi’an 710119China College of life Sciences Shaanxi Normal UniversityXi’an 710119China

Multiple sclerosis(MS)is a chronic and incurable autoimmune disease of the central nervous system(CNS)that results in neuro-inflammation and *** therapies for MS alleviate symptoms to some extent but fail to realize myelin ***,it is crucial to identify effective targets to promote *** a widely expressed transcriptional regulator,peroxisome proliferatoractivated receptor-coactivator-1α(PGC-1α)expresses in different cells with high energy consumption,including skeletal muscle cells,brown fat cells,neurons,astrocytes,and oligodendrocyte precursor cell(OPC)[1].Targeting PGC-1αmay be beneficial for CNS development and various neurodegenerative diseases.

关键词： inflammation myelin autoimmune

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