Taking China’s 2018 value-added tax(VAT)credit refund reform as an exogenous shock to improve VAT neutrality,we use a difference-in-differences approach to explore how the reform affected corporate social responsibil...Taking China’s 2018 value-added tax(VAT)credit refund reform as an exogenous shock to improve VAT neutrality,we use a difference-in-differences approach to explore how the reform affected corporate social responsibility(CSR).We find that the reform motivated firms to improve CSR performance.The reform has a“resource”effect,increasing internal funds and reducing financing costs,thereby enhancing firms’ability to undertake CSR.The reform also has a“reputation”effect,stimulating firms’willingness to engage in CSR to improve their reputations.CSR following the reform increases firm values and reduces bankruptcy risk.Our study provides fresh insights into VAT neutrality theory and is a reference for tax reform in emerging economies.展开更多
Vat photopolymerization(VPP)3D printing is an optimized technology for complex-shaped ceramic cores,in which the solid loading of ceramic slurries greatly infiuences the microstructure and property of the final cerami...Vat photopolymerization(VPP)3D printing is an optimized technology for complex-shaped ceramic cores,in which the solid loading of ceramic slurries greatly infiuences the microstructure and property of the final ceramic parts.However,the high solid loading of slurries is highly limited by the high viscosity.In this study,silica-based ceramic core slurries with solid loading up to 68vol.%were achieved by the composition design to optimize the performance,considering the curing,rheological,and double bond conversion rate.The slurries demonstrate superior curing and rheological performance with mass ratio of monomers being 3:2 and mass fraction of BYK111 being 4wt.%.Afterwards,the impact of solid loading on the morphology and mechanical properties was investigated.As the solid loading increases,the microstructure becomes gradually dense,leading to an improved flexural strength of 19.5 MPa.Additionally,the sintering shrinkage becomes more uniform,satisfying the casting requirements effectively.This work serves as a guide for the preparation of ceramic slurries with a high solid loading.展开更多
As a key process in the manufacturing of hollow turbine blades for aeroengines,ceramic-core stereolithography(SL)is vital for the structural design and precise performance control of hollow turbine blades for aeroengi...As a key process in the manufacturing of hollow turbine blades for aeroengines,ceramic-core stereolithography(SL)is vital for the structural design and precise performance control of hollow turbine blades for aeroengines.Based on SL and digital light processing(DLP),ceramic SL has technical advantages such as high flexibility,short process flow,and integrated structure-performance manufacturing,making it ideal for manufacturing complex hollow ceramic cores.Currently,ceramic cores produced using this technology still encounter several challenges such as low bending strength,low dimensional accuracy,significant sintering shrinkage,and poor surface quality,which limit the innovative development and engineering applications of the additive manufacturing of UV-cured ceramics.This paper reviews the development of additive manufacturing technology and equipment for the vat polymerization of ceramic cores used in aeroengine blades and summarizes the principles and characteristics of vat polymerization for manufacturing ceramic cores.It also highlights research progress in lightweight structural design methods for ceramic cores,ceramic slurry preparation processes,SL processes,debinding and sintering processes,integration of forming system equipment,and verification of aeroengine blade casting.A comprehensive performance control strategy for the SL of ceramic cores is proposed,and future development directions and trends in ceramic-core fabrication using SL technology are discussed.展开更多
To meet the evolving demands of aeroengine development,the structural and performance requirements for ceramic cores have become increasingly stringent.Vat photopolymerization 3D printing,owing to its moldless,fiexibl...To meet the evolving demands of aeroengine development,the structural and performance requirements for ceramic cores have become increasingly stringent.Vat photopolymerization 3D printing,owing to its moldless,fiexible manufacturing,and other advantages,demonstrates significant potential in the preparation of ceramic cores with intricate structures.However,its practical application still faces multiple challenges,including layered structures and property anisotropy,defects such as cracks and collapse during printing and sintering,forming inaccuracies,and difficulties in controlling surface roughness.Recent advances have focused on optimizing slurry formulation and rheology,improving curing behavior,introducing auxiliary powders and additives,tailoring forming parameters,and optimizing the sintering process.Nevertheless,effectively suppressing lamellar defects,achieving superior dimensional accuracy,and maintaining high surface quality in complex structures remain the core scientific and technical issues to be solved.Future research should concentrate on refining curing mechanisms,advancing powder design and organic system optimization,and regulating the coupled processes of forming,debinding,and sintering to accelerate the application of VPP 3D printed ceramic cores in aerospace manufacturing.展开更多
The complex ceramic core used for hollow turbine blades requires a high porosity and a high fiexural strength. For a better balance between porosity and fiexural strength, ceramic materials with porous structures are ...The complex ceramic core used for hollow turbine blades requires a high porosity and a high fiexural strength. For a better balance between porosity and fiexural strength, ceramic materials with porous structures are preferred. In order to achieve the transition from disordered pore formation to ordered pore formation, Al_(2)O_(3) ceramic cores with triply periodic minimal surface(TPMS) micro lattice structures with different structural configurations(gyroid, diamond, and neovius) and different volume fractions of lattice structures(30, 40, and 50, vol.%) were designed and prepared by vat photopolymerization 3D printing. The effects of structural configuration and volume fraction of the lattice structure on the following structural shrinkage, microstructure, and flexural strength were investigated. The shrinkage relationship of the three lattice configurations is: neovius>diamond>gyroid. Besides, it is found that with an increase in the volume fraction of the 3D printed Al_(2)O_(3) ceramic micro lattice structures, their fiexural strength correspondingly increases ranging from 54.95 MPa to 139.1 MPa. The maximum average fiexural strength of the 3D printed Al_(2)O_(3) ceramic micro lattice structures is obtained when the structural configuration is diamond and with a volume fraction of 50vol.%, which is 139.1 MPa. Even when the volume fraction of the lattice structure is 30vol.%, that is to say the porosity is 70%, the fiexural strength is as high as 50-70 MPa, which can still be maintained at a high level. In addition, when the volume fraction of the lattice structure is a certain value, the sample with diamond configuration has a higher strength. The internal pore morphology, pore size, and porosity of the cores are precisely controlled, achieving both a high porosity and a high strength. Therefore, this study maintains high porosity and high strength simultaneously, providing a new lattice structure design idea for 3D printed ceramic cores.展开更多
Mask image projection-based vat photopolymerization(MIP-VPP)offers advantages like low cost,high resolution,and a wide material range,making it popular in industry and education.Recently,MIP-VPP employing liquid cryst...Mask image projection-based vat photopolymerization(MIP-VPP)offers advantages like low cost,high resolution,and a wide material range,making it popular in industry and education.Recently,MIP-VPP employing liquid crystal displays(LCDs)has gained traction,increasingly replacing digital micromirror devices,particularly among hobbyists and in educational settings,and is now beginning to be used in industrial environments.However,LCD-based MIP-VPPsuffers from pronounced pixelated aliasing arising from LCD’s discrete image pixels and itsdirect-contact configuration in MIP-VPP machines,leading to rough surfaces on the 3D-printed parts.Here,we propose a vibration-assisted MIP-VPP method that utilizes a microscalevibration to uniformize the light intensity distribution of the LCD-based mask image on VPP’s building platform.By maintaining the same fabrication speed,our technique generates asmoother,non-pixelated mask image,reducing the roughness on flat surfaces and boundary segments of 3D-printed parts.Through light intensity modeling and simulation,we derived an optimal vibration pattern for LCD mask images,subsequently validated by experiments.We assessed the surface texture,boundary integrity,and dimensional accuracy of componentsproduced using the vibration-assisted approach.The notably smoother surfaces and improved boundary roughness enhance the printing quality of MIP-VPP,enabling its promisingapplications in sectors like the production of 3D-printed optical devices and others.展开更多
Vat photopolymerization(VPP)3D printing technology has broken through mold limitations and shown great potential to manufacture complex-structured ceramic cores for turbine blades.However,improving dimensional accurac...Vat photopolymerization(VPP)3D printing technology has broken through mold limitations and shown great potential to manufacture complex-structured ceramic cores for turbine blades.However,improving dimensional accuracy is difficult for the VPP 3D printed parts due to the high contraction deformation.Reducing shrinkage is a key challenge for developing 3D-printed ceramic cores.In this study,3D-printed alumina ceramic cores with near-zero shrinkage in the X direction were achieved for the first time using a novel approach that was called atmosphere-controlled in-situ oxidation of aluminum powder.The in-situ oxidation reaction of the aluminum powder was creatively tuned by changing the atmosphere transition temperature from argon to air.Then,the microstructure and properties of the ceramic core could be controlled by the liquid-phase sintering with the participation of atmosphere-protected molten aluminum.As a result,the pore size of the ceramic cores was significantly increased by almost ten times,but the bonding strength of the grains was also increased.In addition,the powder consolidation generated by the action of molten aluminum was considered to be an important reason for reducing the linear shrinkage of ceramic cores.Under the optimized parameters,the linear shrinkage of the ceramic cores was as low as 0.3%in the X direction.The high apparent porosity(45.02%)and flexural strength(72.7 MPa)of the alumina ceramic cores were realized at the same time.The in-situ control of sintering by changing the atmosphere will be a creative method for regulating the properties of ceramic materials.展开更多
Introduction: Uniportal Video-Assisted Thoracic Surgery (U-VATS) has appeared as a promising, minimally invasive approach for thoracic oncology, offering benefits such as reduced trauma, shorter recovery times, and lo...Introduction: Uniportal Video-Assisted Thoracic Surgery (U-VATS) has appeared as a promising, minimally invasive approach for thoracic oncology, offering benefits such as reduced trauma, shorter recovery times, and lower complication rates. However, its adoption in resource-limited settings faces challenges, primarily due to limited access to specialized equipment, training, and infrastructure. Methods: This retrospective study evaluated the outcomes of 138 oncologic patients who underwent U-VATS between 2020 and 2024 at two centers in the Dominican Republic. Patients included those with primary lung cancer, pulmonary metastases, or masses requiring diagnostic biopsy. Data was extracted from patient records including epidemiological variables and clinical variables, treatments, and complications. A descriptive analysis was performed to summarize the data. Frequencies and percentages were calculated to report demographic and clinical characteristics, types of procedures, and postoperative outcomes. Results: The study population was predominantly middle-aged, with a near-equal gender distribution. Most patients underwent lung biopsies (63%), followed by lobectomies (22.5%) and metastasectomies (14.5%). The overall complication rate was low, with only 2.1% experiencing wound infections or atelectasis. The majority (87%) were discharged within 24 hours. These findings underscore U-VATS as a safe and effective choice for thoracic oncology in this setting. Conclusions: U-VATS shows promising outcomes in oncologic patients in the Dominican Republic, proving its feasibility and safety in a resource-limited environment. However, widespread adoption requires investment in infrastructure, training, and insurance coverage. Phased implementation, public-private partnerships, and cost-benefit analyses could support broader accessibility and integration of U-VATS, potentially improving patient outcomes and reducing healthcare costs in similar settings.展开更多
Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat phot...Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat photopolymerization(VPP)is an AM method that enables the production of dense ceramic components with increased dimensional accuracy.In particular,it facilitates the fabrication of small and intricately shaped parts.This review summarizes the research advancements in ceramics prepared via VPP.Special attention is paid to the current status of relevant areas,such as slurry preparation and process optimization,as well as the form-ing mechanisms,debinding,sintering,performance characterization,and use of VPP-based ceramics.Moreover,earlier studies performed by our research group on numerous VPP-based ceramic aspects are considered.In ad-dition,a concise overview of the differences in forming principles,mechanical performance,advantages,and disadvantages between VPP-based ceramics and conventional colloidal-forming ceramics is presented.Finally,the challenges and prospects of VPP-based ceramics are discussed.展开更多
The“Announcement on Deepening the Value-Added Tax Reform”clearly outlines the preferential policy regarding incremental retention tax rebates.With the advancement of value-added tax(VAT)reform and the improvement of...The“Announcement on Deepening the Value-Added Tax Reform”clearly outlines the preferential policy regarding incremental retention tax rebates.With the advancement of value-added tax(VAT)reform and the improvement of VAT legislation in China,VAT tax planning for construction enterprises,particularly related to retained tax credits,has become routine.This paper,focusing on the characteristics of construction enterprises,analyzes VAT retained tax credits at the end of the period,the status of tax refunds,practical issues,and related processes,and offers suggestions for policy application and risk prevention.展开更多
Vat photopolymerization additive manufacturing produces lightweight load-bearing ceramic lattice structures that have flexibility,time-efficiency,and high precision,compared to conventional technology.However,understa...Vat photopolymerization additive manufacturing produces lightweight load-bearing ceramic lattice structures that have flexibility,time-efficiency,and high precision,compared to conventional technology.However,understanding the compression behavior and failure mechanism of such structures under loading remains a challenge.In this study,considering the correlation between the strut angle and bearing capacity,body-centered tetragonal(BCT)lattice structures with varying angles are designed based on a body-centered cubic(BCC)structure.BCT Al_(2)O_(3) ceramic lattice structures with varying angles are fabricated by vat photopolymerization.The mechanical properties,deformation process,and failure mechanism of the Al_(2)O_(3) ceramic lattice structures are characterized through a combination of ex-and in-situ X-ray computed tomography(X-CT)compression testing and analyzed using a finite element method(FEM)at macro-and micro-levels.The results demonstrate that as the angle increases,the stress concentration gradually expands from the node to the strut,resulting in an increased loadbearing capacity.Additionally,the failure mode of the Al_(2)O_(3) ceramic lattice structures is identified as diagonal slip shear failure.These findings provide a greater understanding of ceramic lattice structure failures and design optimization approaches.展开更多
基金Scientific Research Project of Higher Education Institutions in Hebei Province in 2025“Research on Government Procurement-Driven Green Governance of Hebei’s Manufacturing Industry”(Project No.:QN2025662)Social Science Fund of Hebei Province in 2024“Research on Informal Environmental Regulation Promoting Green Development of Hebei’s Manufacturing Industry”(Project No.:HB24GL036)Hebei Provincial Social Science Development Research Project,“Study on the Constraints and Implementation Paths of the Transformation from Dual Control of Energy Consumption to Dual Control of Carbon Emissions in Hebei Province”(Project No.:HBSKFZ25QN199)。
文摘Taking China’s 2018 value-added tax(VAT)credit refund reform as an exogenous shock to improve VAT neutrality,we use a difference-in-differences approach to explore how the reform affected corporate social responsibility(CSR).We find that the reform motivated firms to improve CSR performance.The reform has a“resource”effect,increasing internal funds and reducing financing costs,thereby enhancing firms’ability to undertake CSR.The reform also has a“reputation”effect,stimulating firms’willingness to engage in CSR to improve their reputations.CSR following the reform increases firm values and reduces bankruptcy risk.Our study provides fresh insights into VAT neutrality theory and is a reference for tax reform in emerging economies.
基金financially supported by the National Natural Science Foundation of China(No.52102062)the Xi’an Science and Technology Plan Project(No.23LLRH0004)the Key Research and Development Project of Shaanxi Province of China(2024GX-YBXM-352)。
文摘Vat photopolymerization(VPP)3D printing is an optimized technology for complex-shaped ceramic cores,in which the solid loading of ceramic slurries greatly infiuences the microstructure and property of the final ceramic parts.However,the high solid loading of slurries is highly limited by the high viscosity.In this study,silica-based ceramic core slurries with solid loading up to 68vol.%were achieved by the composition design to optimize the performance,considering the curing,rheological,and double bond conversion rate.The slurries demonstrate superior curing and rheological performance with mass ratio of monomers being 3:2 and mass fraction of BYK111 being 4wt.%.Afterwards,the impact of solid loading on the morphology and mechanical properties was investigated.As the solid loading increases,the microstructure becomes gradually dense,leading to an improved flexural strength of 19.5 MPa.Additionally,the sintering shrinkage becomes more uniform,satisfying the casting requirements effectively.This work serves as a guide for the preparation of ceramic slurries with a high solid loading.
基金supported by Jiangsu Provincial Basic Research Program(Natural Science Foundation)Youth Fund(Grant No.BK20230885)International Joint Laboratory of Sustainable Manufacturing,Ministry of Education,Fundamental Research Funds for Central Universities(Grant No.NG2024012)+1 种基金Basic Research Project for Major Special Programs of Aero-Engine and Gas Turbine(Grant No.J2022-Ⅶ-0006-0048)High-Quality Development Special Project of the Ministry of Industry and Information Technology.
文摘As a key process in the manufacturing of hollow turbine blades for aeroengines,ceramic-core stereolithography(SL)is vital for the structural design and precise performance control of hollow turbine blades for aeroengines.Based on SL and digital light processing(DLP),ceramic SL has technical advantages such as high flexibility,short process flow,and integrated structure-performance manufacturing,making it ideal for manufacturing complex hollow ceramic cores.Currently,ceramic cores produced using this technology still encounter several challenges such as low bending strength,low dimensional accuracy,significant sintering shrinkage,and poor surface quality,which limit the innovative development and engineering applications of the additive manufacturing of UV-cured ceramics.This paper reviews the development of additive manufacturing technology and equipment for the vat polymerization of ceramic cores used in aeroengine blades and summarizes the principles and characteristics of vat polymerization for manufacturing ceramic cores.It also highlights research progress in lightweight structural design methods for ceramic cores,ceramic slurry preparation processes,SL processes,debinding and sintering processes,integration of forming system equipment,and verification of aeroengine blade casting.A comprehensive performance control strategy for the SL of ceramic cores is proposed,and future development directions and trends in ceramic-core fabrication using SL technology are discussed.
基金supported by the National Key R&D Program of China(Grant Nos.2024YFB3714502,2024YFB3714501,2024YFB3714504)the National Natural Science Foundation of China(Grant Nos.52130204,52174376)+5 种基金the TQ Innovation Foundation(Grant No.23-TQ09-02-ZT-01-005)the Aeronautical Science Foundation of China(Grant No.20220042053001)the Ningbo Science and Technology Plan Project(Grant No.2025Z070)the Key R&D Project of Shaanxi Province(Grant Nos2024GX-YBXM-220,2024CY-GJHX-29,2024GX-ZDCYL-03-03,2024GX-YBXM-400)the National Advanced Rare Metal Materials Innovation Center Project[Grant No.2024 ZG-GCZX-01(1)-01]the Foundation of China Scholarship Council(Grant No.202406290136)。
文摘To meet the evolving demands of aeroengine development,the structural and performance requirements for ceramic cores have become increasingly stringent.Vat photopolymerization 3D printing,owing to its moldless,fiexible manufacturing,and other advantages,demonstrates significant potential in the preparation of ceramic cores with intricate structures.However,its practical application still faces multiple challenges,including layered structures and property anisotropy,defects such as cracks and collapse during printing and sintering,forming inaccuracies,and difficulties in controlling surface roughness.Recent advances have focused on optimizing slurry formulation and rheology,improving curing behavior,introducing auxiliary powders and additives,tailoring forming parameters,and optimizing the sintering process.Nevertheless,effectively suppressing lamellar defects,achieving superior dimensional accuracy,and maintaining high surface quality in complex structures remain the core scientific and technical issues to be solved.Future research should concentrate on refining curing mechanisms,advancing powder design and organic system optimization,and regulating the coupled processes of forming,debinding,and sintering to accelerate the application of VPP 3D printed ceramic cores in aerospace manufacturing.
基金supported by the National Natural Science Foundation of China (Grant No. 52275310)。
文摘The complex ceramic core used for hollow turbine blades requires a high porosity and a high fiexural strength. For a better balance between porosity and fiexural strength, ceramic materials with porous structures are preferred. In order to achieve the transition from disordered pore formation to ordered pore formation, Al_(2)O_(3) ceramic cores with triply periodic minimal surface(TPMS) micro lattice structures with different structural configurations(gyroid, diamond, and neovius) and different volume fractions of lattice structures(30, 40, and 50, vol.%) were designed and prepared by vat photopolymerization 3D printing. The effects of structural configuration and volume fraction of the lattice structure on the following structural shrinkage, microstructure, and flexural strength were investigated. The shrinkage relationship of the three lattice configurations is: neovius>diamond>gyroid. Besides, it is found that with an increase in the volume fraction of the 3D printed Al_(2)O_(3) ceramic micro lattice structures, their fiexural strength correspondingly increases ranging from 54.95 MPa to 139.1 MPa. The maximum average fiexural strength of the 3D printed Al_(2)O_(3) ceramic micro lattice structures is obtained when the structural configuration is diamond and with a volume fraction of 50vol.%, which is 139.1 MPa. Even when the volume fraction of the lattice structure is 30vol.%, that is to say the porosity is 70%, the fiexural strength is as high as 50-70 MPa, which can still be maintained at a high level. In addition, when the volume fraction of the lattice structure is a certain value, the sample with diamond configuration has a higher strength. The internal pore morphology, pore size, and porosity of the cores are precisely controlled, achieving both a high porosity and a high strength. Therefore, this study maintains high porosity and high strength simultaneously, providing a new lattice structure design idea for 3D printed ceramic cores.
文摘Mask image projection-based vat photopolymerization(MIP-VPP)offers advantages like low cost,high resolution,and a wide material range,making it popular in industry and education.Recently,MIP-VPP employing liquid crystal displays(LCDs)has gained traction,increasingly replacing digital micromirror devices,particularly among hobbyists and in educational settings,and is now beginning to be used in industrial environments.However,LCD-based MIP-VPPsuffers from pronounced pixelated aliasing arising from LCD’s discrete image pixels and itsdirect-contact configuration in MIP-VPP machines,leading to rough surfaces on the 3D-printed parts.Here,we propose a vibration-assisted MIP-VPP method that utilizes a microscalevibration to uniformize the light intensity distribution of the LCD-based mask image on VPP’s building platform.By maintaining the same fabrication speed,our technique generates asmoother,non-pixelated mask image,reducing the roughness on flat surfaces and boundary segments of 3D-printed parts.Through light intensity modeling and simulation,we derived an optimal vibration pattern for LCD mask images,subsequently validated by experiments.We assessed the surface texture,boundary integrity,and dimensional accuracy of componentsproduced using the vibration-assisted approach.The notably smoother surfaces and improved boundary roughness enhance the printing quality of MIP-VPP,enabling its promisingapplications in sectors like the production of 3D-printed optical devices and others.
基金the National Natural Science Foundation of China(Nos.52130204,52174376)the Guangdong Basic and Ap-plied Basic Research Foundation(No.2021B1515120028)+6 种基金the Sci-ence and Technology Innovation Team Plan of Shaan Xi Province(No.2021TD-17)the Youth Innovation Team of Shaanxi Univer-sities,Xi’an Science and Technology Program(No.21ZCZZHXJS-QCY6-0005)the Fundamental Research Funds for the Central Uni-versities(Nos.D5000230348,D5000210902)the TQ Innovation Foundation(No.23-TQ09-02-ZT-01-005)the Aeronautical Science Foundation of China(No.20220042053001)the Thousands Person Plan of Jiangxi Province(No.grant number JXSQ2020102131)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2022033),China.
文摘Vat photopolymerization(VPP)3D printing technology has broken through mold limitations and shown great potential to manufacture complex-structured ceramic cores for turbine blades.However,improving dimensional accuracy is difficult for the VPP 3D printed parts due to the high contraction deformation.Reducing shrinkage is a key challenge for developing 3D-printed ceramic cores.In this study,3D-printed alumina ceramic cores with near-zero shrinkage in the X direction were achieved for the first time using a novel approach that was called atmosphere-controlled in-situ oxidation of aluminum powder.The in-situ oxidation reaction of the aluminum powder was creatively tuned by changing the atmosphere transition temperature from argon to air.Then,the microstructure and properties of the ceramic core could be controlled by the liquid-phase sintering with the participation of atmosphere-protected molten aluminum.As a result,the pore size of the ceramic cores was significantly increased by almost ten times,but the bonding strength of the grains was also increased.In addition,the powder consolidation generated by the action of molten aluminum was considered to be an important reason for reducing the linear shrinkage of ceramic cores.Under the optimized parameters,the linear shrinkage of the ceramic cores was as low as 0.3%in the X direction.The high apparent porosity(45.02%)and flexural strength(72.7 MPa)of the alumina ceramic cores were realized at the same time.The in-situ control of sintering by changing the atmosphere will be a creative method for regulating the properties of ceramic materials.
文摘Introduction: Uniportal Video-Assisted Thoracic Surgery (U-VATS) has appeared as a promising, minimally invasive approach for thoracic oncology, offering benefits such as reduced trauma, shorter recovery times, and lower complication rates. However, its adoption in resource-limited settings faces challenges, primarily due to limited access to specialized equipment, training, and infrastructure. Methods: This retrospective study evaluated the outcomes of 138 oncologic patients who underwent U-VATS between 2020 and 2024 at two centers in the Dominican Republic. Patients included those with primary lung cancer, pulmonary metastases, or masses requiring diagnostic biopsy. Data was extracted from patient records including epidemiological variables and clinical variables, treatments, and complications. A descriptive analysis was performed to summarize the data. Frequencies and percentages were calculated to report demographic and clinical characteristics, types of procedures, and postoperative outcomes. Results: The study population was predominantly middle-aged, with a near-equal gender distribution. Most patients underwent lung biopsies (63%), followed by lobectomies (22.5%) and metastasectomies (14.5%). The overall complication rate was low, with only 2.1% experiencing wound infections or atelectasis. The majority (87%) were discharged within 24 hours. These findings underscore U-VATS as a safe and effective choice for thoracic oncology in this setting. Conclusions: U-VATS shows promising outcomes in oncologic patients in the Dominican Republic, proving its feasibility and safety in a resource-limited environment. However, widespread adoption requires investment in infrastructure, training, and insurance coverage. Phased implementation, public-private partnerships, and cost-benefit analyses could support broader accessibility and integration of U-VATS, potentially improving patient outcomes and reducing healthcare costs in similar settings.
基金supported by Key-Area Research and Devel-opment Program of Guangdong Province of China(Grant No.2020B090923002)Guangdong Basic and Applied Basic Research Foun-dation of China(Grant No.2019B1515130005)+1 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program of China(Grant No.2017BT01C169)Foshan Science and Technology Innovation Team Project of China(Grant No.FS0AA-KJ919-4402-0023).
文摘Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat photopolymerization(VPP)is an AM method that enables the production of dense ceramic components with increased dimensional accuracy.In particular,it facilitates the fabrication of small and intricately shaped parts.This review summarizes the research advancements in ceramics prepared via VPP.Special attention is paid to the current status of relevant areas,such as slurry preparation and process optimization,as well as the form-ing mechanisms,debinding,sintering,performance characterization,and use of VPP-based ceramics.Moreover,earlier studies performed by our research group on numerous VPP-based ceramic aspects are considered.In ad-dition,a concise overview of the differences in forming principles,mechanical performance,advantages,and disadvantages between VPP-based ceramics and conventional colloidal-forming ceramics is presented.Finally,the challenges and prospects of VPP-based ceramics are discussed.
文摘The“Announcement on Deepening the Value-Added Tax Reform”clearly outlines the preferential policy regarding incremental retention tax rebates.With the advancement of value-added tax(VAT)reform and the improvement of VAT legislation in China,VAT tax planning for construction enterprises,particularly related to retained tax credits,has become routine.This paper,focusing on the characteristics of construction enterprises,analyzes VAT retained tax credits at the end of the period,the status of tax refunds,practical issues,and related processes,and offers suggestions for policy application and risk prevention.
基金supported by National Natural Science Foundation of China(Grant Nos.52275310,52402084)the China Postdoctoral Science Foundation(Grant No.2024M751646).
文摘Vat photopolymerization additive manufacturing produces lightweight load-bearing ceramic lattice structures that have flexibility,time-efficiency,and high precision,compared to conventional technology.However,understanding the compression behavior and failure mechanism of such structures under loading remains a challenge.In this study,considering the correlation between the strut angle and bearing capacity,body-centered tetragonal(BCT)lattice structures with varying angles are designed based on a body-centered cubic(BCC)structure.BCT Al_(2)O_(3) ceramic lattice structures with varying angles are fabricated by vat photopolymerization.The mechanical properties,deformation process,and failure mechanism of the Al_(2)O_(3) ceramic lattice structures are characterized through a combination of ex-and in-situ X-ray computed tomography(X-CT)compression testing and analyzed using a finite element method(FEM)at macro-and micro-levels.The results demonstrate that as the angle increases,the stress concentration gradually expands from the node to the strut,resulting in an increased loadbearing capacity.Additionally,the failure mode of the Al_(2)O_(3) ceramic lattice structures is identified as diagonal slip shear failure.These findings provide a greater understanding of ceramic lattice structure failures and design optimization approaches.
