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Effect of microstructure evolution on wear resistance of equal molar CoCrFeNi high-entropy alloy

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Rare Metals 2023年第11期42卷 3797-3805页

作者： Hai-Tao Zhang Cheng-Lin Wang Jun-wei Miao Shu-yan Shi Ting-Ju Li hong-wei yan Yong-An Zhang Yi-Ping Lu Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Engineering Research Center of High Entropy Alloy Materials(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Key Laboratory for Light-weight Materials Nanjing Technology UniversityNanjing210009China State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd.Beijing100088China General Research Institute for Nonferrous Metals Beijing100088China

Face-centered-cubic high-entropy alloys have excellent ductility and great potential for engineering ***,few studies have reported on the wear behavior under different *** study aimed to investigate the tribological behavior of CoCrFeNi highentropy alloy under different *** wear rate increased with the load,and the main wear behavior was abrasive *** cross-sectional microstructure of worn surface consisted of oxide,nanocrystalline,nanolaminated,and deformation *** the higher loads,the deformation mechanism included dislocation slip and deformation twins,and shear bands also *** was unexpectedly found that the wear rate increased sharply under high load,which was attributed to the formation of shear bands and microcracks in the nanocrystalline *** results successfully revealed the great influence of microstructure evolution on the wear rate,providing theoretical guidance for improving the wear resistance of face-centered-cubic high-entropy alloys in the future.

关键词： High-entropy alloys(HEAs) Microstructure evolution Wear mechanism Shear bands

Effects of different concentrations of nicotinamide on hematopoietic stem cells cultured in vitro

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World Journal of Stem Cells 2024年第2期16卷 163-175页

作者： yan Ren yan-Ni Cui hong-wei Wang The Second Clinical Medical College Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina Department of Hematology The Second Hospital of Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina Department of Hematology Key Laboratory of Molecular Diagnosis and Treatment of Blood Diseases in Shanxi ProvinceTaiyuan 030001Shanxi ProvinceChina

BACKGROUND In vitro expansion to increase numbers of hematopoietic stem cells(HSCs)in cord blood could improve clinical efficacy of this vital ***(NAM)can promote HSC expansion ex vivo,but its effect on hematopoietic stem and progenitor cells(HSPCs,CD34^(+)CD38)and functional subtypes of HSCs-shortterm repopulating HSCs(ST-HSCs,CD34^(+)CD38CD45RACD49f^(+))and long-term repopulating HSCs(LT-HSCs,CD34^(+)CD38CD45RACD49f^(+)CD90^(+))is not yet *** a sirtuin 1(SIRT1)inhibitor,NAM participates in regulating cell adhesion,polarity,migration,proliferation,and ***,SIRT1 exhibits dual effects by promoting or inhibiting differentiation in different tissues or *** propose that the concentration of NAM may influence proliferation,differentiation,and SIRT1 signaling of *** To evaluate the effects and underlying mechanisms of action of different concentrations of NAM on HSC proliferation and *** CD34^(+)cells were purified from umbilical cord blood using MacsCD34 beads,and cultured for 10-12 d in a serum-free medium supplemented with cytokines,with different concentrations of NAM added according to experimental *** cytometry was used to detect phenotype,cell cycle distribution,and apoptosis of the cultured ***-time polymerase chain reaction was used to detect the transcription levels of target genes encoding stemness-related factors,che mokines,components of hypoxia pathways,and antioxidant ***-dihydro-fluorescein diacetate probes were used to evaluate intracellular production of reactive oxygen species(ROS).Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead *** Compared with the control group,the proportion and expansion folds of HSPCs(CD34^(+)CD38)incubated with 5 mmol/L or 10 mmol/L NAM were significantly increased(all P<0.05).The ST-HSCs ratio and fold expansion of the 5 mmol/L NAM group were significantly

关键词： Hematopoietic stem cells Nicotinamide Concentration Proliferation Differentiation Sirtuin 1

Low-cycle fatigue behavior of solutionized and aged WE43 magnesium alloys at room temperature

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Journal of Magnesium and Alloys 2024年第6期12卷 2284-2297页

作者： Yong Cai Jianxiong wei hong yan Yipeng Chen Rongshi Chen School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China

The low-cycle fatigue behavior of solutionized(T4)and aged(T6)WE43 magnesium alloys was studied at room *** total strain amplitudes(△ε_(t)/2)were 0.4%,0.5%,0.6%,0.7%and 1.0%.Detailed microstructure evolution was characterized by scanning electron microscope(SEM),electron backscattered diffraction(EBSD)and transmission electron microscopy(TEM).The results showed that plastic strain amplitude decreased with the increasing cycle number in T4 alloy,which is due to the dense persistent slip bands(PSBs)and dynamic precipitates hinderingdislocation *** contrast,the plastic strain amplitude increases gradually in T6 alloy,which is attributed to the enhanced activation of pyramidal *** low-cycle fatigue life of T6 alloy with larger fatigue ductility coefficient is longer than that of T4 *** Coffin-Manson model can accurately predict the fatigue life of T4 and T6 alloys compared to Jahed-Varvani(JV)energy *** T4 alloy,the fatigue damage mechanism was dominated by basal *** T6 alloy,the enhanced pyramidal slip plays an important role to accommodate plastic deformation.

关键词： Low-cycle fatigue WE43 alloy Cyclic hardening/softening JV model Dislocation

非瓣膜性心房颤动患者左心房血栓或自发显影的随机森林模型构建及抗凝结局

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岭南心血管病杂志 2024年第1期30卷 22-27,56页

作者：郑楠刘冰闫洪伟李凤鹏于恺张军河北省沧州市中心医院心血管内五科河北沧州061000

目的构建非瓣膜性心房颤动(non-valvular atrial fibrillation,NVAF)患者左心房血栓(left atrial thrombus,LAT)或自发显影(spontaneous echo contrast,SEC)的随机森林模型,并分析LAT/SEC患者抗凝治疗的临床结局。方法回顾性分析2016年1月至2021年11月河北省沧州市中心医院接受经食管超声心动图检查的NVAF患者的临床资料。构建随机森林模型,通过受试者工作特征曲线(receiver operating characteristic curve,ROC)评价随机森林模型预测LAT/SEC的曲线下面积(area under the curve,AUC),并与CHADS2和CHA2DS2-VASc评分进行对比。结果 386例NVAF患者中,38例(9.8%)发生LAT/SEC。影响LAT/SEC发生的7个最重要的变量是左心室舒张末期内径、估算肾小球滤过率、左心室射血分数、非阵发性心房颤动、左心房内径、未抗凝治疗和脑卒中史。随机森林模型的AUC为0.93(95%CI:0.88~0.99),CHADS2评分的AUC为0.73(95%CI:0.63~0.83),CHA2DS2-VASc评分的AUC为0.72(95%CI:0.62~0.83),随机森林模型的AUC高于CHADS2(Z=3.42,P<0.001)和CHA2DS2-VASc(Z=3.05,P<0.001)评分。随机森林模型预测LAT/SEC的敏感度为92.6%,特异度为89.8%。38例LAT/SEC患者中,55.3%(21/38)患者经抗凝治疗后复查经食管超声心电图,66.7%(14/21)患者LAT/SEC溶解。17例直接口服抗凝剂治疗的患者中,4例LAT和8例SEC溶解;4例华法林治疗的患者中,1例LAT和1例SEC溶解。结论随机森林模型可用于预测NVAF患者LAT/SEC,其诊断效能优于CHADS2及CHA2DS2-VASc评分。三分之二的LAT/SEC患者抗凝治疗后LAT/SEC溶解。

关键词：心房颤动左心房血栓自发显影随机森林

An Accelerated Proximal Gradient Algorithm for Hankel TensorCompletion

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Journal of the Operations Research Society of China 2024年第2期12卷 461-477页

作者： Chuan-Long Wang Xiong-wei Guo Xi-hong yan Key Laboratory of Engineering and Computational Science Shanxi Provincial Department of EducationJinzhong 030619ShanxiChina Department of Mathematics Taiyuan Normal UniversityJinzhong 030619ShanxiChina

In this paper,an accelerated proximal gradient algorithm is proposed for Hankel tensor completion *** our method,the iterative completion tensors generated by the new algorithm keep Hankel structure based on projection on the Hankel tensor ***,due to the special properties of Hankel structure,using the fast singular value thresholding operator of the mode-s unfolding of a Hankel tensor can decrease the computational ***,the convergence of the new algorithm is discussed under some reasonable ***,the numerical experiments show the effectiveness of the proposed algorithm.

关键词： Hankel tensor:Tensor completion Accelerated proximal gradient algorithm

Enhancing personalized exercise recommendation with student and exercise portraits

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Journal of Electronic Science and Technology 2024年第2期22卷 91-109页

作者： wei-wei Gao Hui-Fang Ma yan Zhao Jing Wang Quan-hong Tian College of Computer Science and Engineering Northwest Normal UniversityLanzhou730070China Computer Center of Gansu Province Lanzhou730070China

The exercise recommendation system is emerging as a promising application in online learning scenarios,providing personalized recommendations to assist students with explicit learning *** solutions generally follow a collaborative filtering paradigm,while the implicit connections between students(exercises)have been largely *** this study,we aim to propose an exercise recommendation paradigm that can reveal the latent connections between student-student(exercise-exercise).Specifically,a new framework was proposed,namely personalized exercise recommendation with student and exercise portraits(PERP).It consists of three sequential and interdependent modules:Collaborative student exercise graph(CSEG)construction,joint random walk,and recommendation list ***,CSEG is created as a unified heterogeneous graph with students’response behaviors and student(exercise)***,a joint random walk to take full advantage of the spectral properties of nearly uncoupled Markov chains is performed on CSEG,which allows for full exploration of both similar exercises that students have finished and connections between students(exercises)with similar ***,we propose to optimize the recommendation list to obtain different exercise *** analyses of two public datasets,the results demonstrated that PERP can satisfy novelty,accuracy,and diversity.

关键词： Educational data mining Exercise recommend Joint random walk Nearly uncoupled Markov chains Optimization Personalized learning

Hem-o-lok clip migration to duodenal bulb post-cholecystectomy:A case report

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World Journal of Gastrointestinal Surgery 2024年第5期16卷 1461-1466页

作者： hong-yan Liu Ai-hong Yin Zhi wei Department of Gastroenterology Shandong Second Provincial General HospitalJinan 250022Shandong ProvinceChina

BACKGROUND Hem-o-lok clips are typically used to control the cystic duct and vessels during laparoscopic cholecystectomy(LC)and common bile duct exploration for stones in the bile duct and ***,we report a unique example of Hem-o-lok clip movement towards the duodenal bulb after LC,appearing as a submucosal tumor(SMT).Additionally,we provide initial evidence of gradual and evolving endoscopic manifestations of Hem-o-lok clip migration to the duodenal bulb wall and review the available *** SUMMARY A 72-year-old man underwent LC for gallstones,and Hem-o-lok clips were used to ligate both the cystic duct and cystic ***(EGD)2 years later revealed an SMT-like lesion in the duodenal *** to the symptomatology,the clinical examination did not reveal any major abnormalities,and the patient was followed up as an outpatient.A repeat EGD performed 5 months later revealed an SMT-like lesion in the duodenal bulb with raised edges and a central depression.A third EGD was conducted,during which a Hem-o-lok clip was discovered connected to the front side of the *** clip was extracted easily using biopsy forceps,and no complications *** months after the fourth EGD,the scar was surrounded by normal *** Clinicians should be aware of potential post-LC ***-o-lok clips should be removed if symptomatic.

关键词： Hem-o-lok clip Migration Duodenum Laparoscopic cholecystectomy Laparoscopic common bile duct exploration Case report

Both host and diet shape bacterial communities of predatory mites

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Insect Science 2024年第2期31卷 551-561页

作者： hong yan Endong Wang Guo-Shu wei Bo Zhang Xuenong Xu Institute of Plant Protection Chinese Academy of Agricultural SciencesBejingChina College of Plant Protection Hebei Agricultural UniversityBaodingHebei ProvinceChina Key Laboratory of Natural Enemies Insects Ministry of Agriculture and Rural AffairsBeijingChina

Microbial communities,derived from food,ambient,and inner,can affect host ecological adaption and *** with most phytophagous arthropods,predators may have more opportunities to develop specific microbiota depending on the level of prey *** explore how diet sources affect host microbial communities and vary across predator species,we considered 3 types of predators from Phytoseiidae(Acari:Mesostigmata):polyphagous(Amblyseius orientalis Ehara,Neoseiulus barkeri Hughes,and Amblyseius swirski Athias-Henrio),oligophagous(Neoseiulus californicus McGregor),and monophagous(Phytoseiulus persimilis Athias-Henriot)predatory *** polyphagous species were fed on 2 types of diets,natural prey and alternative *** using 16S rRNA sequencing,we found that diet was the main source of microbiota in predatory mites,while there was no clear pattern affected by prey *** 3 polyphagous predators,host species had a larger impact than prey on microbial *** *** or *** which showed consistency in their microbiota,prey switching significantly affectedβ-diversity of bacterial composition in ***,with 56%of the microbial *** short,our results confirmed the substantial influence of diet on host microbial construction in predatory species,and highlighted species differences in shaping the microbiota which are not necessarily related to prey specialization.

关键词： diet switching feeding habits host-microbial interactions invertebrate microbiota 16S rRNA

Significantly Enhanced Melt Memory Effect of Metallocene-made Isotactic Polypropylene Containing Talc

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Chinese Journal of Polymer Science 2024年第2期42卷 213-222,I0008页

作者： hong-Wen Sun Fu-Shan Wang yan Gao Fu-Qing wei Jia-Chun Feng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China Lanzhou Petrochemical Corporation of PetroChina Lanzhou730060China Lanzhou Petrochemical Research Center Petrochemical Research Institute of PetroChinaLanzhou730060China

The melt memory effect is a widely observed phenomenon in semi-crystalline polymers. In practical applications, various additives are usually introduced into polymers, which may affect their melt memory behavior. In this work, the effect of talc on the melt memory effect of metallocene-made isotactic polypropylene(M-PP) was investigated in detail by using the differential scanning calorimetry. The results indicated that the introduction of talc significantly strengthened the melt memory effect of M-PP. Specifically, the upper limit temperature of Domain II increased from 161 ℃ to 174 ℃, resulting in a substantial widening of the temperature range of Domain IIa from 1 ℃ to 14 ℃. Analysis of the crystal orientation of the M-PP containing talc cooled from various Ts suggested that the remarkably enhanced melt memory effect could be ascribed to the stabilization of oriented nuclei facilitated by talc. This stabilizing effect was likely attributable to the prefreezing effect or the sorption interaction between talc and the M-PP chains.

关键词： Metallocene-made isotactic polypropylene Talc Melt memory effect Crystal orientation