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A numerical study of fluid injection and mixing under near-critical conditions

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Acta Mechanica Sinica 2012年第3期28卷 559-571页

作者： Hua-Guang Li xi-yun lu Vigor Yang Department of Modern Mechanics University of Science and Technology of China230026 HefeiChina School of Aerospace Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

Nitrogen injection under conditions close vicinity of the liquid-gas critical point is studied numerically. The fluid thermodynamic and transport properties vary drasti- cally and exhibit anomalies in the near-critical regime. These anomalies can cause distinctive effects on heat-transfer and fluid-flow characteristics. To focus on the influence of ther- modynamics on the flow field, a relatively low injection Reynolds number of 1 750 is adopted. For comparisons, a reference case with the same configuration and Reynolds number is simulated in the ideal gas regime. The model accommodates full conservation laws, real-fluid thermody- namic and transport phenomena. Results reveal that the flow features of the near-critical fluid jet are significantly differ- ent from their counterpart. The near-critical fluid jet spreads faster and mixes more efficiently with the ambient fluid along with a more rapidly development of the vortex pairing pro- cess. Detailed analysis at different streamwise locations in- cluding both the flat shear-layer region and fully developed vortex region reveals the important effect of volume dilata- tion and baroclinic torque in the near-critical fluid case. The former disturbs the shear layer and makes it more unstable. The volume dilatation and baroclinic effects strengthen the vorticity and stimulate the vortex rolling up and pairing pro- cess

关键词： Liquid-gas critical point Real-fluid Fluid in-jection Shear layer instability Vortical dynamics

Dynamic performance and wake structure of flapping plates with different shapes

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Acta Mechanica Sinica 2014年第6期30卷 800-808页

作者： Gao-Jin Li Nan-Sheng Liu xi-yun lu Department of Modern Mechanics University of Science and Technology of China

The dynamic performance and wake structure of flapping plates with different shapes were studied using multi-block lattice Boltzman and immersed boundary *** typical regimes relevant to thrust behavior are *** is nonlinear relation between the thrust and the area moment of plate for lower area moment region and the other is linear relation for larger area moment *** tendency of the power variation with the area moment is reasonably similar to the thrust behavior and the efficiency decreases gradually as the area moment *** the mechanism of the dynamic properties is associated with the evolution of vortical structures around the plate,the formation and evolution of vortical structures are investigated and the effects of the plate shape,plate area,Strouhal number and Reynolds number on the vortical structures are *** results obtained in this study provide physical insight into the understanding of the mechanisms relevant to flapping locomotion.

关键词： Dynamics of flapping plate Flapping locomotion Plate shape Vortex dynamics

Upadacitinib for refractory ulcerative colitis with primary nonresponse to infliximab and vedolizumab:A case report

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World Journal of Clinical Cases 2024年第9期12卷 1685-1690页

作者： Xuan Xu Jing-Wen Jiang Bing-yun lu xia-xi Li Department of Gastroenterology Shenzhen HospitalSouthern Medical UniversityShenzhen 518100Guangdong ProvinceChina The First Clinical Medical School Southern Medical UniversityGuangzhou 510515Guangdong ProvinceChina

BACKGROUND Many patients with ulcerative colitis(UC)do not respond well to,or tolerate conventional and biological *** is currently no consensus on the treatment of refractory *** have demonstrated that the selective Janus kinase 1 inhibitor upadacitinib,a small-molecule drug,is effective and safe for treating ***,no studies have revealed that upadacitinib is effective in treating refractory UC with primary nonresponse to infliximab and *** SUMMARY We report the case of a 44-year-old male patient with a chief complaint of bloody diarrhoea with mucus and pus,in addition to *** patient had recurrent disease after receiving mesalazine,prednisone,azathioprine,infliximab and vedolizumab over four *** on the endoscopic findings and pathological biopsy,the patient was diagnosed with refractory *** particular,the patient showed primary nonresponse to infliximab and *** on the patient’s history and recurrent disease,we decided to administer *** hospitalisation,the patient was received upadacitinib under our *** weeks after the initiation of upadacitinib treatment,the patient’s symptoms and endoscopic findings improved *** notable adverse reactions have been reported to *** Our case report suggests that upadacitinib may represent a valuable strategy for treating refractory UC with primary nonresponse.

关键词： Upadacitinib Refractory ulcerative colitis Primary nonresponse Infliximab Vedolizumab Case report

Large Eddy Simulation of a Vortex Ring Impacting a Bump

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Advances in Applied Mathematics and Mechanics 2014年第3期6卷 261-280页

作者： Heng Ren Ning Zhao xi-yun lu Department of Modern Mechanics University of Science and Technology of ChinaHefei 230026AnhuiChina Department of Aerodynamics Nanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuChina

A vortex ring impacting a three-dimensional bump is studied using large eddy simulation for a Reynolds number Re=4×104 based on the initial diameter and translational speed of the vortex *** effects of bump height and vortex core thickness for thin and thick vortex rings on the vortical flow phenomena and the underlying physical mechanisms are *** on the analysis of the evolution of vortical structures,two typical kinds of vortical structures,i.e.,the wrapping vortices and the hair-pin vortices,are identified and play an important role in the flow state *** boundary vorticity flux is analyzed to reveal the mechanism of the vorticity generation on the bump *** circulation of the primary vortex ring reasonably elucidates some typical phases of flow ***,the analysis of turbulent kinetic energy reveals the transition from laminar to turbulent *** results obtained in this study provide physical insight into the understanding of the mechanisms relevant to the flow evolution and the flow transition to turbulent state.

关键词： Large eddy simulation vortex ring vortical structure turbulent state.

Experimental distillation of tripartite quantum steering with an optimal local filtering operation

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Photonics Research 2024年第3期12卷 552-562页

作者： QIAN-xi ZHANG xiAO-XU FANG HE lu School of Physics State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China Shenzhen Research Institute of Shandong University Shenzhen 518057China

Multipartite Einstein-Podolsky-Rosen(EPR)steering admits multipartite entanglement in the presence of uncharacterized verifiers,enabling practical applications in semi-device-independent *** applications generally require stronger steerability,while the unavoidable noise weakens steerability and consequently degrades the performance of quantum information ***,we propose the local filtering operation that can maximally distill genuine tripartite EPR steering from N copies of three-qubit generalized Greenberger-Horne-Zeilinger states,in the context of two semi-device-independent *** optimal filtering operation is determined by the maximization of assemblage *** and numerical results indicate the advantage of the proposed filtering operation when N is finite and the steerability of initial assemblages is ***,a proof-of-principle demonstration of two-copy distillation is realized with the optical *** advantage of the optimal local filtering operation is confirmed by the distilled assemblage in terms of higher assemblage fidelity with perfectly genuine tripartite steerable assemblages,as well as the greater violation of the inequality to witness genuine tripartite steerable *** results benefit the distillation of multipartite EPR steering in practice,where the number of copies of initial assemblages is generally finite.

关键词： filtering distillation optimal

A state-of-the-art review of the development of self-healing concrete for resilient infrastructure

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 151-169页

作者： Dong lu xi JIANG Yao ZHANG Shaowei ZHANG Guoyang lu Zhen LENG Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China Laboratory of Fire Safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Architecture and Civil Engineering City University of Hong KongHong Kong 999077China

The brittleness of cement composites makes cracks almost inevitable,producing a serious limitation on the lifespan,resilience,and safety of concrete *** address this brittleness,self-healing concrete has been developed for regaining its mechanical and durability properties after becoming cracked,thereby promising sustainable development of concrete *** paper provides a comprehensive review of the latest developments in self-healing *** begins by summarizing the methods used to evaluate the self-healing efficiency of ***,it compares strategies for achieving healing *** then discusses the typical approaches for developing self-healing ***,critical insights are proposed to guide future studies on the development of novel self-healing *** review will be useful for researchers and practitioners interested in the field of self-healing concrete and its potential to improve the durability,resilience,and safety of concrete infrastructure.

关键词： resilient infrastructure sustainable concrete self-healing cracks

Numerical Investigation of the Dynamics of a Flexible Filament in the Wake of Cylinder

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Advances in Applied Mathematics and Mechanics 2014年第4期6卷 478-493页

作者： Ru-Nan Hua luoding Zhu xi-yun lu Department of Modern Mechanics University of Science and Technology of ChinaHefei 230026China Department of Mathematical Sciences Indiana University-Purdue University Indianapolis402 North Blackford StreetIndianapolisIN 46202USA

Fluid-structure-interaction problems are ubiquitous,complicated,and not yet well *** this paper we investigate the interaction of a leading rigid circular cylinder and a trailing compliant filament and analyze the dynamic responses of the filament in the wake of the *** is revealed that there exist two flapping states of the filament depending on the cylinder-filament separation distance and the relevant critical distance distinguishing the two states is associated with the Reynolds number and the filament *** is also found that the drag coefficient of the cylinder is reduced but that of the filament may be increased or decreased depending on its *** with a single filament in a uniform flow,the filament of the same mechanical properties flapping in the wake of the cylinder has a lower frequency and a greater amplitude.

关键词： Fluid-structure interaction immersed boundary-lattice Boltzmann method

Diabetes mellitus in patients with type 1 autoimmune pancreatitis at diagnosis and after corticosteroid therapy

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Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 393-398页

作者： Mei-Zi Li Tao Guo yun-lu Feng Sheng-Yu Zhang xiao-Yin Bai xi Wu Kai Xu Ai-Ming Yang Department of Gastroenterology State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China Department of Radiology Peking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China

Background:A high prevalence of diabetes mellitus(DM)coexisting with autoimmune pancreatitis(AIP)is ***,evidence on the circumstances under which corticosteroid therapy(CST)for AIP improves or worsens DM is *** study aimed to demonstrate and identify predictors of DM control under the influence of ***:Patients diagnosed with type 1 AIP were enrolled from a prospectively maintained cohort and were classified into three groups according to the chronology in which AIP and DM were diagnosed:pre-existing DM(pDM),concurrent DM(cDM),and non-DM(nDM).The responses of DM to CST were assessed when corticosteroid was ceased or tapered to a maintenance dose and classified as‘improvement’and‘non-improvement’(including‘no change’and‘exacerbation’).Results:Among 101 patients with type 1 AIP,52(51.5%)patients were complicated with DM at the time of AIP diagnosis,with 36 patients in the cDM group and 16 patients in the pDM *** incidences of diffuse pancreatic swelling(72.2%)and pancreatic body/tail involvement(91.7%)were significantly higher in the cDM group than in both the pDM and nDM *** the 52 patients with DM,CST was administered in 48 *** logistic analysis identified that elevated serum gamma-glutamyl transferase(GGT)level at AIP diagnosis[odds ratio(OR)=0.032,95%confidence interval(CI):0.003-0.412,P=0.008]and pancreatic atrophy after CST(OR=0.027,95%CI:0.003-0.295,P=0.003)were negatively associated with DM control ***:Patients with diffuse pancreatic swelling and pancreatic body/tail involvement in pancreatitis tended to be complicated with cDM at AIP *** exerted a beneficial effect on the clinical course of DM in nearly half of the AIP patients complicated with DM at diagnosis,particularly in those without elevated serum GGT levels at diagnosis and who did not experience pancreatic atrophy after CST.

关键词： Type 1 autoimmune pancreatitis Diabetes mellitus Corticosteroid therapy Predictive factor Pancreatic atrophy

Cobalt-catalyzed reductive alkynylation to construct C(sp)-C(sp^(3))and C(sp)-C(sp^(2))bonds

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Chinese Chemical Letters 2024年第7期35卷 253-258页

作者： Lei Wan Yizhou Tong xi lu Yao Fu Hefei National Research Center for Physical Sciences at the Microscale iChEMCAS Key Laboratory of Urban Pollutant ConversionAnhui Province Key Laboratory of Biomass Clean EnergyUniversity of Science and Technology of ChinaHefei 230026China Key Laboratory of Precision and Intelligent Chemistry School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefei 230026China

Transition-metal-catalyzed cross-electrophile coupling has emerged as a reliable method for constructing carbon–carbon ***,we report a general method,cobalt-catalyzed reductive alkynylation,to construct C(sp)-C(sp^(3))and C(sp)-C(sp^(2))*** presented reaction has a broad substrate scope,enabling the efficient cross-electrophile coupling between alkynyl bromides with alkyl halides and aryl or alkenyl(pseudo)*** presented reaction is conducted under mild conditions,tolerating many functional groups,thus suitable for the modification and synthesis of biologically active molecules.

关键词： Cobalt-catalysis Cross-electrophile coupling Carbon-carbon bond formation Reductive alkynylation Alkyne synthesis