The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar microstructures.In this study,the inf...The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar microstructures.In this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was investigated.The results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' matrix.Aging at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine microstructure.By increasing the aging temperature,the number of α_(s) decreases but with coarsened microstructures.When aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°C.The changing size of α_(s) obviously influences the property of the alloy.The fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.展开更多
Metal-free room-temperature phosphorescence(RTP)materials are of great significance for many applications;however,they usually exhibit low efficiency and weak intensity.This article reports a new strategy for the prep...Metal-free room-temperature phosphorescence(RTP)materials are of great significance for many applications;however,they usually exhibit low efficiency and weak intensity.This article reports a new strategy for the preparation of a high-efficiency and strong RTP materials from crystalline thermal-annealed carbon dots(CDs)and boric acid(BA)composite(g-t-CD@BA)through grinding-induced amorphous to crystallization transition.Amorphous thermal-annealed CDs and BA composite(t-CD@BA)is prepared following a thermal melting and super-cooling route,where the CDs are fully dispersed in molten BA liquid and uniformly frozen in an amorphous thermal annealed BA matrix after super-cooling to room temperature.Upon grinding treatment,the fracture and fragmentation caused by grinding promote the transformation of the high-energy amorphous state to the lower energy crystalline counterparts.As a result,the CDs are uniformly in situ embedded in the BA crystal matrix.This method affords maximum uniform embedding of the CDs in the BA crystals,decreases nonradiative decay,and promotes intersystem crossing by restraining the free vibration of the CDs,thus producing strong RTP materials with the highest reported phosphorescence quantum yield(48%).Remarkably,RTP from g-t-CD@BA powder is strong enough to illuminate items with a delay time exceeding 9 s.展开更多
Objective:To examine the leakage radiation dose from the accelerator module's primary beam self-shielding,aswell as stray radiation levels and distribution in the treatment room across various planes for the innov...Objective:To examine the leakage radiation dose from the accelerator module's primary beam self-shielding,aswell as stray radiation levels and distribution in the treatment room across various planes for the innovative X/γmultimodal radiotherapy system,TaiChi Pro,which is the world's first digitally integrated system that combines alinear accelerator,multi-source rotational focused gamma knife,and multi-modal image guidance,in order toformulate treatment room safety strategies and estimate additional radiation doses to patients.Methods:The TaiChi Pro multi-mode integrated radiotherapy system was utilized with a 6 MV X-ray accelerator inthe flatten-filter free(FFF)treatment mode.The system has a primary radiation beam self-shielding,and anisocenter dose rate of 800 cGy/min.For detection points in various planes,an x,y,z coordinate system wasestablished with the isocenter as the origin.To simulate the situation of patient,water-equivalent phantom wasemployed.The ambient dose equivalent and ambient dose equivalent rate at detection points in the radiation fieldwere measured using thermoluminescence dosimeters.Results:The self-shielding area achieved a maximum dose of 114.0 mGy at 1 m distance from the target point after3 min of cumulative irradiation.The leakage radiation ratios at all points remained below 0.5%,fulfilling the selfshielding design requirements.Regarding the couch,the highest radiation was observed in the opposite directionof the beam at the target point.The stray radiation on the treatment bed plane resulted in an ambient doseequivalent that did not exceed 0.5%of the ambient dose equivalent at the central point.Conclusion:The levels and distribution patterns of stray and leakage radiation inside the TaiChi Pro treatmentroom meet the requirements of the relevant national standard.The measured values of indoor radiation levels anddistribution are very useful for room shielding design and personnel protection.展开更多
BACKGROUND Acute portal vein thrombosis(PVT)with bowel necrosis is a fatal condition with a 50%-75%mortality rate.This report describes the successful endovascular treatment(EVT)of two patients with severe PVT.CASE SU...BACKGROUND Acute portal vein thrombosis(PVT)with bowel necrosis is a fatal condition with a 50%-75%mortality rate.This report describes the successful endovascular treatment(EVT)of two patients with severe PVT.CASE SUMMARY The first patient was a 22-year-old man who presented with abdominal pain lasting 3 d.The second patient was a 48-year-old man who presented with acute abdominal pain.Following contrast-enhanced computed tomography,both patients were diagnosed with massive PVT extending to the splenic and superior mesenteric veins.Hybrid treatment(simultaneous necrotic bowel resection and EVT)was performed in a hybrid operating room(OR).EVTs,including aspiration thrombectomy,catheter-directed thrombolysis(CDT),and continuous CDT,were performed via the ileocolic vein under laparotomy.The portal veins were patent 4 and 6 mo posttreatment in the 22-year-old and 48-year-old patients,respectively.CONCLUSION Hybrid necrotic bowel resection and transileocolic EVT performed in a hybrid OR is effective and safe.展开更多
基金financially supported by the Beijing Municipal Science and Technology Project(No.Z171100000817002)the Young Elite Scientist Sponsorship Program by CAST and the National Key Research and Development Program of China(No.2016YFB1100401)。
文摘The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar microstructures.In this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was investigated.The results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' matrix.Aging at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine microstructure.By increasing the aging temperature,the number of α_(s) decreases but with coarsened microstructures.When aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°C.The changing size of α_(s) obviously influences the property of the alloy.The fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.
基金the National Natural Science Foundation of China(No.52002152,62005106 and 61922091)the Natural Science Foundation of Jiangsu(BK20190864 and BK20190865)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions(19KJB430014)the Science and Technology Development Fund of Macao SAR(0040/2019/A1,0128/2020/A3,0131.2020.A3 and 0073/2019/AMJ)Fund from the University of Macao(SRG2019‐00163‐IAPME)the High-Tech Research Key Laboratory of Zhenjiang(SS2018002).
文摘Metal-free room-temperature phosphorescence(RTP)materials are of great significance for many applications;however,they usually exhibit low efficiency and weak intensity.This article reports a new strategy for the preparation of a high-efficiency and strong RTP materials from crystalline thermal-annealed carbon dots(CDs)and boric acid(BA)composite(g-t-CD@BA)through grinding-induced amorphous to crystallization transition.Amorphous thermal-annealed CDs and BA composite(t-CD@BA)is prepared following a thermal melting and super-cooling route,where the CDs are fully dispersed in molten BA liquid and uniformly frozen in an amorphous thermal annealed BA matrix after super-cooling to room temperature.Upon grinding treatment,the fracture and fragmentation caused by grinding promote the transformation of the high-energy amorphous state to the lower energy crystalline counterparts.As a result,the CDs are uniformly in situ embedded in the BA crystal matrix.This method affords maximum uniform embedding of the CDs in the BA crystals,decreases nonradiative decay,and promotes intersystem crossing by restraining the free vibration of the CDs,thus producing strong RTP materials with the highest reported phosphorescence quantum yield(48%).Remarkably,RTP from g-t-CD@BA powder is strong enough to illuminate items with a delay time exceeding 9 s.
基金supported by the Construction Project of High-Level Public Health Technical Personnel in Beijing(Academic Leader-01-20),China.
文摘Objective:To examine the leakage radiation dose from the accelerator module's primary beam self-shielding,aswell as stray radiation levels and distribution in the treatment room across various planes for the innovative X/γmultimodal radiotherapy system,TaiChi Pro,which is the world's first digitally integrated system that combines alinear accelerator,multi-source rotational focused gamma knife,and multi-modal image guidance,in order toformulate treatment room safety strategies and estimate additional radiation doses to patients.Methods:The TaiChi Pro multi-mode integrated radiotherapy system was utilized with a 6 MV X-ray accelerator inthe flatten-filter free(FFF)treatment mode.The system has a primary radiation beam self-shielding,and anisocenter dose rate of 800 cGy/min.For detection points in various planes,an x,y,z coordinate system wasestablished with the isocenter as the origin.To simulate the situation of patient,water-equivalent phantom wasemployed.The ambient dose equivalent and ambient dose equivalent rate at detection points in the radiation fieldwere measured using thermoluminescence dosimeters.Results:The self-shielding area achieved a maximum dose of 114.0 mGy at 1 m distance from the target point after3 min of cumulative irradiation.The leakage radiation ratios at all points remained below 0.5%,fulfilling the selfshielding design requirements.Regarding the couch,the highest radiation was observed in the opposite directionof the beam at the target point.The stray radiation on the treatment bed plane resulted in an ambient doseequivalent that did not exceed 0.5%of the ambient dose equivalent at the central point.Conclusion:The levels and distribution patterns of stray and leakage radiation inside the TaiChi Pro treatmentroom meet the requirements of the relevant national standard.The measured values of indoor radiation levels anddistribution are very useful for room shielding design and personnel protection.
文摘BACKGROUND Acute portal vein thrombosis(PVT)with bowel necrosis is a fatal condition with a 50%-75%mortality rate.This report describes the successful endovascular treatment(EVT)of two patients with severe PVT.CASE SUMMARY The first patient was a 22-year-old man who presented with abdominal pain lasting 3 d.The second patient was a 48-year-old man who presented with acute abdominal pain.Following contrast-enhanced computed tomography,both patients were diagnosed with massive PVT extending to the splenic and superior mesenteric veins.Hybrid treatment(simultaneous necrotic bowel resection and EVT)was performed in a hybrid operating room(OR).EVTs,including aspiration thrombectomy,catheter-directed thrombolysis(CDT),and continuous CDT,were performed via the ileocolic vein under laparotomy.The portal veins were patent 4 and 6 mo posttreatment in the 22-year-old and 48-year-old patients,respectively.CONCLUSION Hybrid necrotic bowel resection and transileocolic EVT performed in a hybrid OR is effective and safe.
