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High strength Al-Cu-mg based alloy with synchronous improved tensile properties and hot-cracking resistance suitable for laser powder b e d fusion

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Journal of materials Science & Technology 2023年第10期141卷 155-170页

作者： Q.Z.Wang N.Kang X.Lin m.EL mansori W.d.Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Arts et metiers Institute of Technology MSMPHESAM UniversitéChâlons-en-Champagne F-51006France Key Laboratory of metal High Performance Additive manufacturing and Innovative design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China Texas A&m Engineering Experiment Station Institute for Manufacturing SystemsCollege StationTX 77843USA

In present work,a novel crack-free Al-Cu-mg-Si-Ti alloy with synchronous improved tensile properties and hot-cracking resistance was proposed and successfully manufactured by laser powder bed fusion(LPBF).The microstructure evolution behaviors and the corresponding strengthening mechanisms were investigated in *** LPBF-processed Al-Cu-mg-Si-Ti alloy presents a heterogeneous microstructure consisting of ultrafine equiaxed grains(UFGs)at the boundary and coarse columnar grains(CGs)at the center of the single molten ***-precipitated d022-Al 3 Ti particles were found to act as the nuclei to refine the grains at the boundary of the molten pool during solidification process,which is attributed to the low cooling rate providing the sufficient incubation time for the precipitation of d022-Al 3 *** are two orientation relationships(ORs)betweenα-Al and d022-Al 3 Ti,i.e.[001]α-Al//[001]d022-Al3Ti,(200)α-Al//(200)d022-Al3Ti and[1¯1¯2]α-Al//[¯111]d022-Al3Ti,(1¯11)α-Al//(¯11¯2)d022-Al3Ti,which are two of the eight ORs predicted with the E2em *** grains in present alloy,no matter for UFGs or CG,exhibited high critical hot-cracking stress,which means a strong hot-cracking ***-nanoprecipitation of Cu-,mg-,and Si-rich Q’and S’phases was introduced to enhance the mechanical performance ofα-Al *** as-built sample exhibits superior tensile properties,with the yield strength(YS)of 473±8 mPa,ultimate tensile strength(UTS)of 541±2 mPa and elongation(EI)of 10.9%±1.2%.

关键词： Laser powder bed fusion High strength Al-Cu-mg alloys duplex microstructure Precipitation Tensile properties

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Learning two-phase microstructure evolution using neural operators and autoencoder architectures

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npj Computational materials 2022年第1期8卷 1804-1816页

作者： Vivek Oommen Khemraj Shukla Somdatta Goswami Rémi dingreville George em Karniadakis School of Engineering Brown UniversityProvidenceRIUSA division of Applied mathematics Brown UniversityProvidenceRIUSA Center for Integrated Nanotechnologies Sandia National LaboratoriesAlbuquerqueNM87185USA

Phase-field modeling is an effective but computationally expensive method for capturing the mesoscale morphological and microstructure evolution in ***,fast and generalizable surrogate models are needed to alleviate the cost of computationally taxing processes such as in optimization and design of *** intrinsic discontinuous nature of the physical phenomena incurred by the presence of sharp phase boundaries makes the training of the surrogate model *** develop a framework that integrates a convolutional autoencoder architecture with a deep neural operator(deepONet)to learn the dynamic evolution of a two-phase mixture and accelerate time-to-solution in predicting the microstructure *** utilize the convolutional autoencoder to provide a compact representation of the microstructure data in a low-dimensional latent *** deepONet is trained in the latent space,it can be used to replace the high-fidelity phase-field numerical solver in interpolation tasks or to accelerate the numerical solver in extrapolation tasks.

关键词： materials phase operators

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Implications of crude oil pollution on natural regeneration of plant species in an oil-producing community in the Niger delta Region of Nigeria

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Journal of Forestry Research 2014年第4期25卷 915-921页

作者： U.d Chima G.Vure department of Forestry and Wildlife management University of Port Harcourt- Choba P.M.B. 5323 Port Harcourt Rivers State Nigeria

The study evaluated the impact of crude oil pollution on natu- ral regeneration of plant species in a major oil-producing community in the Niger delta region of Nigeria. Three sites--unpolluted site （US）, polluted and untreated site （PUS）, and polluted and treated site （PTS）-- were purposively chosen for the study. The seedling emergence method was used to evaluate soil seed banks in the various sites at two depths, 0 to 10 cm and 10 to 20 cm. Woody-plant species richness, abundance, and diversity were higher in the US seed bank than in the PUS and PTS seed banks. The highest number of non-woody plants was observed in the US, followed by the PTS, and then the PUS. Both species richness and diversity of non-woody plants were highest at the US, followed by the PUS, and lowest in the PTS. Woody species in the US seed bank were 87.5% and 80% dissimilar with those of the PUS and PTS at 0-10 cm and 10--20 cm respectively. No variation was observed between woody species in the PUS and PTS seed banks. Non-woody species at 0-10 em US seed bank were 73.08% dissimilar with those of PUS at the two soil depths and 81.48/88.46% dissimilar with those of the 0-10/10-20 cm of the PTS respectively. At 10-20 cm, non-woody species of theUS were 69.66% dissimilar with those from each of the two soil depths in PUS; and 73.91/81.82% dissimilar with those of 0-10/10-20 cm of the PTS respectively. Non-woody species variation between the PUS and PTS was higher at 10-20 cm than 0-10 cm. The poor seed bank attributes at the polluted sites demonstrates that crude oil pollution negatively af- fected the natural regeneration potential of the native flora because soil seed banks serve as the building blocks for plant succession. Thorough rem.diation and enrichment planting are recommended to support the recovery process of vegetation in the polluted areas.

关键词： Ogoni land crude oil pollution rem.diation plant regeneration

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Autoimmune gastritis presenting as iron deficiency anemia in childhood

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World Journal of Gastroenterology 2014年第42期20卷 15780-15786页

作者： Cristina Gon?alves maria emília Oliveira Ana m Palha Anabela Ferr?o Anabela morais Ana Isabel Lopes Gastroenterology Unit Pediatric Department University Hospital Santa Maria Lisbon Academic Medical Centre Pathology department University Hospital Santa Maria Lisbon Academic Medical Centre Hematology Unit Pediatric Department University Hospital Santa Maria Lisbon Academic Medical Centre

AIm: To characterize clinical, laboratorial, and histological profile of pediatric autoimmune gastritis in the setting of unexplained iron deficiency anemia investigation.

关键词： Autoimmune gastritis Iron deficiency anemia Children

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Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons,emergency medicine physicians,and general surgeons in the United States

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World Journal of emergency medicine 2023年第4期14卷 294-301页

作者： Fady Y.Hijji Andrew d.Schneider matthew d.Thomas Joseph G.Lyons daniel d.Bohl Jennifer L.Jerele michael J.Prayson department of Orthopaedic Surgery Wright State University Boonshoft School of MedicineDayton OH 45409USA department of Orthopaedic Surgery Rush University Medical CenterChicago IL 60612USA

BACKGROUNd:Few contemporary studies have assessed physicians’knowledge of radiation exposure associated with common imaging studies,especially in trauma *** purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal(mSK)imaging studies routinely utilized in the trauma ***:An electronic survey was distributed to United States orthopaedic surgery,general surgery,and emergency medicine(em)residency *** were asked to estimate the radiation dose for common imaging modalities of the pelvis,lumbar spine,and lower extremity,in terms of chest X-ray(CXR)*** estimates were compared to the true effective radiation ***,participants were asked to report the frequency of discussing radiation risk with ***:A total of 218 physicians completed the survey;102(46.8%)were em physicians,88(40.4%)wereorthopaedicsurgeons,and28(12.8%)*** underestimated the effective radiation doses of nearly all imaging modalities,most notably for pelvic computed tomaography(CT)(median 50 CXR estimation vs.162 CXR actual)and lumbar CT(median 50 CXR estimation vs.638 CXR actual).There was no difference between physician specialties regarding estimation accuracy(P=0.133).Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure(P=0.007).CONCLUSION:The knowledge among orthopaedic and general surgeons and em physicians regarding the radiation exposure associated with common mSK trauma imaging is *** investigation with larger scale studies is warranted,and additional education in this area may improve care.

关键词： Radiation dosage Radiation exposure Radiation protection X-ray emergency department

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Role of microbial dysbiosis in the pathogenesis of esophageal mucosal disease:A paradigm shift from acid to bacteria?

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World Journal of Gastroenterology 2021年第18期27卷 2054-2072页

作者： Steve m d'Souza Kevin Houston Lauren Keenan Byung Soo Yoo Parth J Parekh david A Johnson department of Internal medicine Division of GastroenterologyEastern Virginia Medical SchoolNorfolkVA 23502United States

Genomic sequencing,bioinformatics,and initial speciation(e.g.,relative abundance)of the commensal microbiome have revolutionized the way we think about the“human”body in health and *** interactions between the gut bacteria and the immune system of the host play a key role in the pathogenesis of gastrointestinal diseases,including those impacting the *** relatively stable,there are a number of factors that may disrupt the delicate balance between the luminal esophageal microbiome(em)and the *** changes are thought to be a product of age,diet,antibiotic and other medication use,oral hygiene,smoking,and/or expression of antibiotic products(bacteriocins)by other *** effects may lead to persistent dysbiosis which in turn increases the risk of local inflammation,systemic inflammation,and ultimately disease *** has suggested that the etiology of gastroesophageal reflux disease-related esophagitis includes a cytokine-mediated inflammatory component and is,therefore,not merely the result of esophageal mucosal exposure to corrosives(i.e.,acid).emerging evidence also suggests that the em plays a major role in the pathogenesis of disease by inciting an immunogenic response which ultimately propagates the inflammatory ***,we discuss the potential role for manipulating the em as a therapeutic option for treating the root cause of various esophageal disease rather than just providing symptomatic relief(i.e.,acid suppression).

关键词： microbiome Gastroesophageal reflux disease Probiotics Prebiotics Bacteriocins dysbiosis Barrett’s esophagus Esophageal cancer Esophagitis Eosinophilic esophagitis

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Comparing the force due to the Lennard-Jones potential and the Coulomb force in the SPH method

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Journal of Ocean Engineering and Science 2018年第4期3卷 310-315页

作者： d.A.Barbosa F.P.Piccoli Octopus dofleini:Environmental Physics/Laboratory of Simulation of Flows with Free Surface-Federal University of Espírito Santo Brazil Laboratory of Simulation of Flows with Free Surface-Federal University of Espírito Santo Brazil

Seventy years after the Smoothed Particle Hydrodynamics(SPH)method was created,there was the need to use the solid limit to keep the domain particles of a certain *** boundary’s treatment is usually done with the use of force derived from potential *** our paper,a new boundary treatment technique is ***,we use the Coulomb force to exert a repulsive force on the border to avoid outgoing particles leaving the simulation *** test this new technique,the problem of dam break and sloshing was simulated.©2018 Shanghai Jiaotong *** by Elsevier B.V.

关键词： Repulsive force SPH Coulomb Force Lennard-Jones.

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Bi-Orthogonal fPINN:A Physics-Informed Neural Network method for Solving Time-dependent Stochastic Fractional PdEs

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Communications in Computational Physics 2023年第9期34卷 1133-1176页

作者： Lei ma Rongxin Li Fanhai Zeng Ling Guo George em Karniadakis department of mathematics Shanghai Normal UniversityShanghai 200234China School of mathematics Shandong UniversityShandong 250100China division of Applied mathematics Brown UniversityProvidenceRI 02906USAand School of EngineeringBrown UniversityProvidenceRI 02906USA

Fractional partial differential equations(FPdEs)can effectively represent anomalous transport and nonlocal ***,inherent uncertainties arise naturally in real applications due to random forcing or unknown material *** models considering nonlocal interactions with uncertainty quantification can be formulated as stochastic fractional partial differential equations(SFPdEs).There are many challenges in solving SFPdEs numerically,especially for long-time integration since such problems are high-dimensional and ***,we combine the bi-orthogonal(BO)method for representing stochastic processes with physicsinformed neural networks(PINNs)for solving partial differential equations to formulate the bi-orthogonal PINN method(BO-fPINN)for solving time-dependent ***,we introduce a deep neural network for the stochastic solution of the time-dependent SFPdEs,and include the BO constraints in the loss function following a weak *** automatic differentiation is not currently applicable to fractional derivatives,we employ discretization on a grid to compute the fractional derivatives of the neural network *** weak formulation loss function of the BO-fPINN method can overcome some drawbacks of the BO methods and thus can be used to solve SFPdEs with eigenvalue ***,the BO-fPINN method can be used for inverse SFPdEs with the same framework and same computational complexity as for forward *** demonstrate the effectiveness of the BO-fPINN method for different benchmark ***,we first consider an SFPdE with eigenvalue crossing and obtain good results while the original BO method *** then solve several forward and inverse problems governed by SFPdEs,including problems with noisy initial *** study the effect of the fractional order as well as the number of the BO modes on the accuracy of the BO-fPINN *** results demonstrate the flexibility and efficiency

关键词： Scientific machine learning uncertainty quantification stochastic fractional differential equations PINNs inverse problems

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Recurrence of inflammatory pseudotumor in the distal bile duct: Lessons learned from a single case and reported cases

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World Journal of Gastroenterology 2006年第24期12卷 3938-3943页

作者： em López-Tomassetti Fernández H díaz Luis A martín malagón I Arteaga González A Carrillo Pallarés department of Gastrointestinal Surgery University Hospital of Canary Islands Ofra s/n. La Cuesta38320 La LagunaSanta Cruz de TenerifeSpain

Inflammatory myofibroblastic tumors （ImTs） or inflammatory pseudotumors （IPs） have been extensively discussed in the literature. They are usually found in the lung and upper respiratory tract. However, reporting of cases involving the biliopancreatic region has increased over recent years. Immunohistochemical study of these lesions limited to the pancreatic head or distal bile duct seems to be compatible with those observed in a new entity called autoimmune pancreatitis, but usually intense fibrotic reaction （zonation） predominates producing a mass. When this condition is limited to the pancreatic head, the common bile duct might be involved by the inflammatory process and jaundice may occur often resembling adenocarcinoma of the pancreas. We have previously reported a case of ImT arising from the bile duct associated with autoimmune pancreatitis which is an extremely rare entity. Four years after Kaush-Whipple resection, radiological examination on routine follow-up revealed a tumor mass, suggesting local recurrence. Ultrasound-guided FNA confirmed our suspicious diagnosis. This present case, as others, suggests that persistent follow-up is necessary in order to prevent irreversible liver damage at this specific location.

关键词： Inflammatory myofibroblastic tumor Inflammatory pseudotumor Local recurrence Pancreasresection Whipple procedure

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Timing of Proterozoic magmatism in the Sunsas belt, Bolivian Precambrian Shield, SW Amazonian Craton

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Geoscience Frontiers 2021年第6期12卷 277-293页

作者： Ingrid m.Nedel Reinhardt A.Fuck Amarildo S.Ruiz Gerardo R.matos-Salinas Alanielson da C.d.Ferreira Instituto de Geociências Universidade de Brasília(UnB)Brasília-DFBrazil Faculdade de Geociências Universidade Federal de Mato GrossoCuiabá-MTBrazil Instituto de Investigaciones Geológicas y del medio Ambiente Universidad Mayor de San Andrés(UMSA)Pabellón GeologíaCalle 27Campus Universitario Cota CotaLa PazBolivia department of Earth Sciences Stellenbosch UniversityPrivate Bag X1Matieland7602 StellenboschSouth Africa

We present new U–Pb zircon and monazite ages from the Sunsas belt granitic magmatism in Bolivia, SW Amazonian Craton. The geochronological results revealed four major magmatic events recorded along the Sunsas belt domains. The older igneous event formed a granitic basement coeval to the Rio Apa Terrane(1.95–1.85 Ga) in the southern domain. The second magmatic episode is represented by 1.68 Ga granites associated to the Paraguá Terrane(1.69–1.66 Ga) in the northern domain. The 1.37–1.34 Ga granites related to San Ignacio orogeny represent the third and more pervasive magmatic event, recorded throughout the Sunsas belt. moreover, magmatic ages of ~1.42 Ga revealed that the granitogenesis associated to the Santa Helena orogeny also affected the Sunsas belt, indicating that it was not restricted to the Jauru Terrane. Lastly, the 1.10–1.04 Ga youngest magmatism was developed during the Sunsas orogeny and represents the final magmatic evolution related to Rodinia assembly. Likewise, the 1.95–1.85 and 1.68 Ga inherited zircon cores obtained in the ~1.3 Ga and 1.0 Ga granite samples suggest strong partial melting of the Paleoproterozoic sources. The 1079 ± 14 ma and 1018 ± 6 ma monazite crystallization ages can be correlated to the collisional tectono-thermal event of the Sunsas orogeny, associated to reactions of medium-to high-grade metamorphism. Thus, the Sunsas belt was built by heterogeneous 1.95–1.85 Ga and 1.68 Ga crustal fragments that were reworked at 1.37–1.34 Ga and 1.10–1.04 Ga related to orogenic collages. Furthermore, the 1.01 Ga monazite age suggests that granites previously dated by zircon can bear evidence of a younger thermal history. Therefore, the geochronological evolution of the Sunsas belt may have been more complex than previously thought.

关键词： SW Amazonian Craton Sunsas belt U–Pb geochronology Zircon monazite

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