The use of light metals today is of great importance,for example in the automotive,aviation and aerospace industries,where energy consumption is minimized and thus the economy is being attempted.By using light metals,...The use of light metals today is of great importance,for example in the automotive,aviation and aerospace industries,where energy consumption is minimized and thus the economy is being attempted.By using light metals,weight is reduced so that energy is saved.Aluminum and magnesium alloys are particularly used thanks to their lightweight.Vehicles in the automotive,aerospace and space industries are expected not only to have lightweight but also high static and dynamic strengths since they are exposed to static and dynamic cyclic loads.However,the structural components can quickly become fatigued and fail under cyclic load due to the notch factor of the joining zones.Compared to the fusion welding method,joining of material is realized mechanically below the melting point of the material in the friction stir spot welding(FSSW)method.Thus,the fatigue strength of the assembly is much higher than that of the fusion welding.In this study,light metal alloy of magnesium AZ31B and aluminum EN AW 2024 were joined with FSSW method and mechanical properties of this joins were also carried out.展开更多
Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to the...Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to theircommercialization. Here we present a brief summary of our studies on both extrinsic and intrinsic causes for the fastdegradation of OLEDs. In particular, we focus on the origin of the dark spots by 'rebuilding' cathodes, which confirms thatthe growth of dark spots occurs primarily due to cathode delamination. In the meantime, we recapture the findings from thesearch for suitable OLED packaging materials, in particular polymer composites, which provide both heat dissipation andmoisture resistance, in addition to electrical insulation.展开更多
Phosphor-in-glass(PiG)film is a promising luminescent material in high-brightness laser lighting for its advantages of high efficiency,outstanding color quality,and low-cost preparation,which must bear high laser powe...Phosphor-in-glass(PiG)film is a promising luminescent material in high-brightness laser lighting for its advantages of high efficiency,outstanding color quality,and low-cost preparation,which must bear high laser power(LP)and laser power density(LPD)simultaneously to enable high-luminance light.Herein,laser spot associated high-saturation PiG film was proposed for transmissive and reflective high-brightness laser lighting.Two types of PiG films were prepared by printing and sintering La_(3)Si_(6)N_(11):Ce^(3+)(LSN)phosphor-borosilicate glass pastes on a sapphire substrate(PiG-S)and an AlN substrate(PiG-A),respectively.The PiG films with perfect crystal structure of phosphor were reliably bonded on the substrates.The effects of laser spot areas on the luminescence saturation of LP and LPD were investigated in the PiG films.With the increase of laser spot area from 0.5 to 2.5 mm^(2),the LP threshold of PiG films is gradually raised,while the LPD threshold of PiG films is decreased.The PiG-S withstands a high LP of 23.46 W and a high LPD of 20.64 W/mm^(2),enabling white light with a luminous flux of 3677 lm.The PiG-A withstands a high LP of 41.12 W and a high LPD of 35.56 W/mm^(2),enabling white light with a luminous flux of 2882 lm.Moreover,the PiG-A maintains lower working temperature compared with the PiG-S,and the temperatures reduce with the increasing laser spot area.The results demonstrate that the laser spot associated PiG films realize high saturation thresholds of LP and LPD simultaneously,and enable high luminance for laser lighting.展开更多
In this study,we constructed two annular detector arrays comprising 24 wedge-shaped CsI(Tl) crystals,and tested them using anαsource and radioactive beams of ^(14-16) Con a CD_2 target.We compared the properties of a...In this study,we constructed two annular detector arrays comprising 24 wedge-shaped CsI(Tl) crystals,and tested them using anαsource and radioactive beams of ^(14-16) Con a CD_2 target.We compared the properties of a CsI(Tl) crystal encapsulated with various reflectors,revealing that using the 80-μm-thick ESR film to pack the CsI(Tl) crystal yielded the largest light output with the smallest non-uniformity in light output (ΔLO).For the 24 CsI(Tl) detectors with the 80-μm-thick ESR films,the average energy resolution improved as the average light output increased;however,it deteriorated as theΔLO value increased.To form two annular Si-CsI(Tl) telescopes for identifying the light-charged particles,theΔLO value and energy resolution of each CsI(Tl) detector were maintained under 20%and 7.7%,respectively.These telescopes were tested for the first time in a direct nuclear reaction experiment using ^(14-16) C+d.The results demonstrated that the Z=1 and Z=2 charged particles were adequately discriminated by the telescopes using the standardΔE-E method.展开更多
文摘The use of light metals today is of great importance,for example in the automotive,aviation and aerospace industries,where energy consumption is minimized and thus the economy is being attempted.By using light metals,weight is reduced so that energy is saved.Aluminum and magnesium alloys are particularly used thanks to their lightweight.Vehicles in the automotive,aerospace and space industries are expected not only to have lightweight but also high static and dynamic strengths since they are exposed to static and dynamic cyclic loads.However,the structural components can quickly become fatigued and fail under cyclic load due to the notch factor of the joining zones.Compared to the fusion welding method,joining of material is realized mechanically below the melting point of the material in the friction stir spot welding(FSSW)method.Thus,the fatigue strength of the assembly is much higher than that of the fusion welding.In this study,light metal alloy of magnesium AZ31B and aluminum EN AW 2024 were joined with FSSW method and mechanical properties of this joins were also carried out.
文摘Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to theircommercialization. Here we present a brief summary of our studies on both extrinsic and intrinsic causes for the fastdegradation of OLEDs. In particular, we focus on the origin of the dark spots by 'rebuilding' cathodes, which confirms thatthe growth of dark spots occurs primarily due to cathode delamination. In the meantime, we recapture the findings from thesearch for suitable OLED packaging materials, in particular polymer composites, which provide both heat dissipation andmoisture resistance, in addition to electrical insulation.
基金supported by the National Natural Science Foundation of China(51805196 and 51775219)National Key R&D Program of China(2022YFB3604803)Key Research and Development Program of Hubei Province(2021BAA213 and 2020BAB068).
文摘Phosphor-in-glass(PiG)film is a promising luminescent material in high-brightness laser lighting for its advantages of high efficiency,outstanding color quality,and low-cost preparation,which must bear high laser power(LP)and laser power density(LPD)simultaneously to enable high-luminance light.Herein,laser spot associated high-saturation PiG film was proposed for transmissive and reflective high-brightness laser lighting.Two types of PiG films were prepared by printing and sintering La_(3)Si_(6)N_(11):Ce^(3+)(LSN)phosphor-borosilicate glass pastes on a sapphire substrate(PiG-S)and an AlN substrate(PiG-A),respectively.The PiG films with perfect crystal structure of phosphor were reliably bonded on the substrates.The effects of laser spot areas on the luminescence saturation of LP and LPD were investigated in the PiG films.With the increase of laser spot area from 0.5 to 2.5 mm^(2),the LP threshold of PiG films is gradually raised,while the LPD threshold of PiG films is decreased.The PiG-S withstands a high LP of 23.46 W and a high LPD of 20.64 W/mm^(2),enabling white light with a luminous flux of 3677 lm.The PiG-A withstands a high LP of 41.12 W and a high LPD of 35.56 W/mm^(2),enabling white light with a luminous flux of 2882 lm.Moreover,the PiG-A maintains lower working temperature compared with the PiG-S,and the temperatures reduce with the increasing laser spot area.The results demonstrate that the laser spot associated PiG films realize high saturation thresholds of LP and LPD simultaneously,and enable high luminance for laser lighting.
基金supported by the National Natural Science Foundation of China (Nos.12275007, U1867214, 11775004)the funding from the State Key Laboratory of Nuclear Physics and Technology,Peking University,China (No. NPT2021ZZ01)funding from heavy Ion Research Facility,Lanzhou,China (No. HIR2021PY002)。
文摘In this study,we constructed two annular detector arrays comprising 24 wedge-shaped CsI(Tl) crystals,and tested them using anαsource and radioactive beams of ^(14-16) Con a CD_2 target.We compared the properties of a CsI(Tl) crystal encapsulated with various reflectors,revealing that using the 80-μm-thick ESR film to pack the CsI(Tl) crystal yielded the largest light output with the smallest non-uniformity in light output (ΔLO).For the 24 CsI(Tl) detectors with the 80-μm-thick ESR films,the average energy resolution improved as the average light output increased;however,it deteriorated as theΔLO value increased.To form two annular Si-CsI(Tl) telescopes for identifying the light-charged particles,theΔLO value and energy resolution of each CsI(Tl) detector were maintained under 20%and 7.7%,respectively.These telescopes were tested for the first time in a direct nuclear reaction experiment using ^(14-16) C+d.The results demonstrated that the Z=1 and Z=2 charged particles were adequately discriminated by the telescopes using the standardΔE-E method.
