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Numerical simulation of three dimensional concrete printing based on a unified fluid and solid mechanics formulation

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 491-515页

作者： Janis REINOLD Koussay da.DOUCH günther MESCHKE Institute for Structural Mechanics Ruhr University BochumBochum 44801Germany

Deformation control constitutes one of the main technological challenges in three dimensional(3D)concrete printing,and it presents a challenge that must be addressed to achieve a precise and reliable construction ***-based information of the expected deformations and stresses is required to optimize the construction process in association with the specific properties of the concrete *** this work,a novel thermodynamically consistent finite strain constitutive model for fresh and early-age 3D-printable concrete is *** model is then used to simulate the 3D concrete printing process to assess layer shapes,deformations,forces acting on substrate layers and prognoses of possible structural collapse during the layer-by-layer *** constitutive formulation is based on a multiplicative split of the deformation gradient into elastic,aging and viscoplastic parts,in combination with a hyperelastic potential and considering evolving material properties to account for structural buildup or *** advantage of this model is the stress-upda.e-scheme,which is similar to that of small strain plasticity and therefore enables an efficient integration with existing material *** constitutive model uses the particle finite element method,which serves as the simulation framework,allowing for modeling of the evolving free surfaces during the extrusion *** analyses of three printed layers are used to create deformation plots,which can then be used to control the deformations during 3D concrete *** study offers further investigations,on the structural level,focusing on the potential structural collapse of a 3D printed concrete *** capability of the proposed model to simulate 3D concrete printing processes across the scales—from a few printed layers to the scale of the whole printed structure—in a unified fashion with one constitutive formulation,is demonstrated.

关键词： particle finite element method 3D concrete printing multiplicative split additive manufacturing elastoviscoplasticity

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Unveiling the early universe:Axion-like particles and their role in primordial structure formation

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 178-179页

作者： Sergey g.Rubin National Research Nuclear University MEPhI(Moscow Engineering Physics Institute) Moscow 115409Russia

The groundbreaking discovery of gravitational waves(gWs)by the LIgO-VIRgO-KAgRO collaboration has revolutionized our understanding of the universe and opened up a new way of observing cosmic events. Unlike light waves... 详细信息

关键词： universe gravitational cosmic

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Summary of a Life in Observational Ultraviolet/Optical Astronomy

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Research in Astronomy and Astrophysics 2024年第1期24卷 1-43页

作者： Donald g.York Department of Astronomy and Astrophysics The University of Chicago5801 South Ellis Ave.Chicago 60637ILUSA

I reminisce on my early life in Section 1;on my education in Sections 2 and 3;on the years at Princeton as a research astronomer in Section 4;on the years on the faculty at Chicago in Section 5;on research on Diffuse Interstellar Bands(DIBs) in Section 6;on construction of the 3.5 m telescope at Apache Point Observatory(APO)in Section 7;on work on the Sloan Digital Sky Survey(SDSS) in Section 8;on work in public education in Chicago in Section 9;and on my travels in Section 10. My main science research is of an observational nature,concerning galactic and intergalactic interstellar gas. Highlights for me included my work on the orbiting telescope Copernicus, including the discovery of interstellar deuterium;early observations of absorption associated with fivetimes ionized oxygen;and discoveries concerning the phases of gas in the local interstellar medium, based on previously unobservable interstellar UV spectral lines. With other instruments and collaborations, I extended interstellar UV studies to the intergalactic cool gas using quasi-stellar object QSO absorption lines redshifted to the optical part of the spectrum;provided a better definition of the emission and morphological character of the source of absorption lines in QSO spectra;and pursued the identification of the unidentified DIBs. For several of these topics, extensive collaborations with many scientists were essential over many years. The conclusions developed slowly, as I moved from being a graduate student at Chicago, to a research scientist position at Princeton and then to a faculty position at Chicago. At each stage of life, I was exposed to new technologies ada.table to my science and to subsequent projects. From high school da.s, I encountered several management opportunities which were formative. I have been extremely fortunate both in scientific mentors I had and in experimental opportunities I encountered.

关键词： Interstellar Medium(ISM) Nebulae (galaxies:)quasars:absorption lines ultraviolet:stars

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Revealing the Hydrogenation Mechanism of g-C3N4 for Understanding the Enhanced Photocatalytic Performance

Revealing the Hydrogenation Mechanism of g-C3N4 for Understa...

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第十一届新型太阳能材料科学与技术学术研讨会

作者： da.Zhan Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences

A simple,facile and effective method to simultaneously exfoliate and hydrogenate gCN through high concentration sulfuric acid treatment is *** hydrogenation mechanism of graphitic-CN （g-CN） is revealed by molecular structure dynamic *** is found that there are 4 different atomic sites in unit cell of g-CN are structurally available and energetically favored to be *** energetically favored hydrogenation structure of g-CN possesses the corrugated basal *** bandgap of gCN becomes larger due to *** photocatalytic performance of g-CNis dramatically enhanced after *** to that of the pristine g-CN,the enhanced photocatalytic performance of the hydrogenated g-CN is mainly attributed to the hydrogenation caused redistribution of density of states as well as the effective spatial charge separation （Figure 1）.The revealing of the hydrogenation mechanism of g-CN is of great importance for further discovering the potential applications of this metal-free material.

关键词： graphitic-C3N4 hydrogenation charge separation

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Verification and Valida.ion of High-Resolution Inviscid and Viscous Conical Nozzle Flows

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Communications on Applied Mathematics and Computation 2024年第1期6卷 533-549页

作者： Luciano K.Araki Rafael B.de R.Borges Nicholas Dicati P.da.Silva Chi-Wang Shu Department of Mechanical Engineering Federal University of ParanáCuritiba81531-980ParanáBrazil Mathematics and Statistics Institute Rio de Janeiro State UniversityRio de Janeiro20550-900Rio de JaneiroBrazil Department of Mechanical Engineering State University of MaringáMaringá87020-900ParanáBrazil Division of Applied Mathematics Brown UniversityProvidenceRI02912USA

Capturing elaborated flow structures and phenomena is required for well-solved numerical *** finite difference methods allow simple discretization of mesh and model ***,they need simpler meshes,e.g.,*** inverse Lax-Wendroff(ILW)procedure can handle complex geometries for rectangular ***-resolution and high-order methods can capture elaborated flow structures and *** also have strong mathematical and physical backgrounds,such as positivity-preserving,jump conditions,and wave propagation *** perceive an effort toward direct numerical simulation,for instance,regarding weighted essentially non-oscillatory(WENO)***,we propose to solve a challenging engineering application without turbulence *** aim to verify and valida.e recent high-resolution and high-order *** check the solver accuracy,we solved vortex and Couette ***,we solved inviscid and viscous nozzle flows for a conical *** employed the finite difference method,positivity-preserving Lax-Friedrichs splitting,high-resolution viscous terms discretization,fifth-order multi-resolution WENO,ILW,and third-order strong stability preserving *** showed the solver is high-order and captured elaborated flow structures and *** can see oblique shocks in both nozzle *** the viscous flow,we also captured a free-shock separation,recirculation,entrainment region,Mach disk,and the diamond-shaped pattern of nozzle flows.

关键词： High-resolution Compressible Navier-Stokes Free-shock separation Nozzle flow

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From the dust:extracellular vesicles as regulators of development and neuroregeneration

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Neural Regeneration Research 2024年第5期19卷 933-934页

作者： Leon g.Coleman Jr The University of North Carolina at Chapel Hill School of MedicineDepartment of PharmacologyBowles Center for Alcohol StudiesChapel HillNCUSA

First impressions can have a lasting *** science,this can be especially problematic,because our lack of understanding often causes us to mislabel and thus ignore important biological *** this vein,extracellular vesicles(EVs)were once considered to be“cellular dust”.Similar to the previous concept of“junk DNA”to describe protein non-coding regions,EVs are far more than just cellular *** fact,EVs are emerging as key mediators of intracellular communication across nearly all biological *** includes peripheral immune responses(e.g.,arthropathies and sepsis),intra-organ communication(Seim et al.,2023),and a host of other physiological and pathological states(Figure 1A and B).

关键词： Figure extracellular

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Metabolic disease and the liver: A review

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World Journal of Hepatology 2024年第1期16卷 33-40页

作者： Márcia Vargas Sheila de Castro Cardoso Toniasso Patricia g Riedel Camila Pereira Baldin Francielle Lopes dos Reis Robson Martins Pereira Maria Carlota Borba Brum Dvora Joveleviths Mario Reis Alvares-da.Silva Program of graduate Science in gastroenterology and Hepatology Federal University of Rio Grande do SulPorto Alegre 90040-060Rio Grande do SulBrazil School of Medicine Federal University of Rio Grande do SulPorto Alegre 90040-060Brazil Program of graduate Science in gastroenterology and Hepatology Clinicas Hospital of Porto AlegrePorto Alegre 90410000Brazil Medicine Faculty Federal University of Rio grande do Sul Federal University of Rio Grande do SulPorto Alegre 90040-060Brazil Division of gastroenterology and Hepatology Clinicas Hospital of Porto AlegrePorto Alegre 90035007Brazil

Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most common liver disease worldwide,with an estimated prevalence of 31%in Latin *** presence of metabolic comorbidities coexisting with liver disease varies substantially among *** is acknowledged that obesity is boosting the type 2 diabetes mellitus“epidemic,”and both conditions are significant contributors to the increasing number of patients with *** steatohepatitis represents a condition of chronic liver inflammation and is considered the most severe form of *** diagnosis is based on the presence of steatosis,noninvasive scores and altered liver *** scores of liver fibrosis,such as serum biomarkers,which should be used in primary care to rule out advanced fibrosis,are simple,inexpensive,and widely ***,guidelines from international hepatology societies recommend using noninvasive strategies to simplify case finding and management of high-risk patients with MASLD in clinical ***,there is no definite pharmacological treatment for the *** public health policies to treat patients with risk factors for MASLD prevention is essential.

关键词： Nonalcoholic fatty liver disease Primary care Metabolic risk Liver Metabolism

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Endotoxin-induced alterations of adipose tissue function:a pathway to bovine metabolic stress

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Journal of Animal Science and Biotechnology 2024年第4期15卷 1391-1407页

作者： Miguel Chirivi g.Andres Contreras Department of Large Animal Clinical Sciences Michigan State UniversityEast LansingMIUSA

During the periparturient period, da.ry cows exhibit negative energy balance due to limited appetite and increased energy requirements for lactogenesis. The delicate equilibrium between energy availability and expenditure puts cows in a state of metabolic stress characterized by excessive lipolysis in white adipose tissues(AT), increased production of reactive oxygen species, and immune cell dysfunction. Metabolic stress, especially in AT, increases the risk for metabolic and inflammatory diseases. Around parturition, cows are also susceptible to endotoxemia. Bacterial-derived toxins cause endotoxemia by promoting inflammatory processes and immune cell infiltration in different organs and systems while impacting metabolic function by altering lipolysis, mitochondrial activity, and insulin sensitivity. In da.ry cows, endotoxins enter the bloodstream after overcoming the defense mechanisms of the epithelial barriers, particularly during common periparturient conditions such as mastitis, metritis, and pneumonia, or after abrupt changes in the gut microbiome. In the bovine AT, endotoxins induce a pro-inflammatory response and stimulate lipolysis in AT, leading to the release of free fatty acids into the bloodstream. When excessive and protracted, endotoxin-induced lipolysis can impair adipocyte's insulin signaling pathways and lipid synthesis. Endotoxin exposure can also induce oxida.ive stress in AT through the production of reactive oxygen species by inflammatory cells and other cellular components. This review provides insights into endotoxins' impact on AT function, highlighting the gaps in our knowledge of the mechanisms underlying AT dysfunction, its connection with periparturient cows' disease risk, and the need to develop effective interventions to prevent and treat endotoxemia-related inflammatory conditions in da.ry cattle.

关键词： Adipose tissue dysfunction Endotoxin Inflammation Insulin resistance

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Interpreting siliciclastic sedimentation in the upper Paleozoic Mulargia-Escalaplano Basin(Sardinia, Italy):influence of tectonics on provenance

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Journal of Palaeogeography 2024年第1期13卷 18-34页

作者： Luca g.Costamagna Sara Criniti Dipartimento di Scienze Chimiche e geologiche Citadella UniversitariaBlocco A09042 Monserrato CAItaly Dipartimento di Ingegneria dell'Ambiente Universita della Calabria87036 Arcavacata di Rende CSItaly

Late to post-Variscan molassic basins of Late Pennsylvanian-Permian age are exposed in Sardinia(Italy). Here, the compositional and stratigraphic evolution of the Mulargia-Escalaplano sedimentary basin(central Sardinia) has been investigated to highlight how the tectono-magmatic processes have influenced the sedimentation. Ruditic and arenitic samples were collected along well-characterized stratigraphic sections to provide a new insight into the impact of the tectono-magmatic processes on siliciclastic sedimentation. As a result, the conglomerates are mainly clast-supported, petromictic, and thus immature, with no defined maturity trend upwards. Nevertheless, pebble composition changes in times from Variscan basement pebble-rich to volcanic rock-rich, as a consequence of the basin widening and the dismantling and reworking of the coeval volcanic activity. The sandstone composition clearly changes from quartzolithic to feldspatholithic upwards, as a response to the same change of feeding and reworking of the volcanic rocks. Occasionally, interbedded quartzolithic arenites suggest exceptional floods carrying debris from the far borders of the basin. Also, the immature sandstone composition has been interpreted as being controlled by a continuous supply of fresh debris and to a rapid burial rate. In addition, the disappearance of metaradiolarite(lydite AA) Paleozoic grains in the sandstone mineral suite could represent a distinctive marker of a progressive unroofing of the Variscan chain and a clastic supply from deeper tectonic units.

关键词： Petrography Stratigraphy Provenance Molassic basins Sardinia

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Effectiveness and Safety of Qishen Yiqi Dripping Pill in Patients with Acute Coronary Syndrome after Percutaneous Coronary Intervention:3-Year Results from a Multicentre Cohort Study

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Chinese Journal of Integrative Medicine 2024年第10期30卷 877-885页

作者： BAI Rui-na gU Feng CHE Qian-zi ZHANg Xuan CAI Ya-jie XI Rui-xi ZHAO Yang gUO Ming DONg guo-ju gAO Zhu-ye FU Chang-geng WANg Pei-li DU Jian-peng ZHANg da.wu DUAN Wen-hui LI Li-zhi YANg Qiao-ning SHI da.zhuo Department of Cardiovascular Xiyuan HospitalChina Academy of Chinese Medical SciencesBeijing100091China National Clinical Research Center for Chinese Medicine Cardiology Beijing100091China Department of Evidence-Based Medicine Basic Research Laboratory Institute of Basic Research in Clinical MedicineChina Academy of Chinese Medical SciencesBeijing100700China Department of Traditional Chinese Medicine Beijing Shangdi HospitalBeijing100193China National Medical Products Administration Key Laboratory for Clinical Research and Evaluation of Traditional Chinese MedicineBeijing100091China

Objectives:To evaluate the effectiveness and safety of Qishen Yiqi Dripping Pill(QSYQ)in patients with acute coronary syndrome(ACS)after percutaneous coronary intervention(PCI).Methods:This multicentre prospective cohort study was conducted at 40 centers in *** with ACS after PCI entered either the QSYQ or Western medicine(WM)groups naturally based on whether they had received QSYQ before *** group received QSYQ(0.52 g,3 times a da. for 12 months)in addition to *** primary endpoint included cardiac death,non-fatal myocardial infarction,and urgent *** seconda.y endpoint included rehospitalization due to ACS,heart failure,stroke,and other thrombotic *** of life was assessed by the Seattle Angina Questionnaire(SAQ).Results:A total of 936 patients completed follow-up of the primary endpoint from February 2012 to December ***,487 patients received QSYQ and *** a median follow-up of 566 da.s(inter quartile range,IQR,517–602),the primary endpoint occurred in 46(9.45%)and 65(14.48%)patients in QSYQ and WM groups respectively[adjusted hazard ratio(HR)0.60,95%confidence interval(CI)0.41–0.90;P=0.013].The seconda.y endpoint occurred in 61(12.53%)and 74(16.48%)patients in QSYQ and WM groups,respectively(adjusted HR 0.76,95%CI 0.53–1.09;P=0.136).In sensitivity analysis,the results still demonstrated that WM combined with QSYQ reduced the risk of the primary endpoint(HR 0.67,95%CI 0.46–0.98;P=0.039).Moreover,QSYQ improved the disease perception domain of the SAQ(Pgs provide a promising option for managing ACS after PCI and suggest the potential treatment for reducing the risk of primary endpoint included cardiac death,non-fatal myocardial infarction,and urgent revascularization through intermittent administration of QSYQ.(Registration *** CTR-OOC-14005552).

关键词： Qishen Yiqi Dripping Pill acute coronary syndrome percutaneous coronary intervention primary and seconda.y endpoint

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