The potential of bulk-like WTe2 particles for the realization of a passive Q-switch operating at the 1 μm wavelength was investigated. The WTe2 particles were prepared using a simple mechanical exfoliation method tog...The potential of bulk-like WTe2 particles for the realization of a passive Q-switch operating at the 1 μm wavelength was investigated. The WTe2 particles were prepared using a simple mechanical exfoliation method together with Scotch tape. By attaching bulk-like WTe2 particles, which remained on the top of the sticky surface of a small segment of the Scotch tape, to the flat side of a side-polished fiber, a saturable absorber（SA） was readily implemented. A strong saturable absorption was then readily obtained through an evanescent field interaction with the WTe2 particles. The modulation depth of the prepared SA was measured as ~2.18% at 1.03 μm. By incorporating the proposed SA into an all-fiberized ytterbium-doped fiber ring cavity, stable Qswitched pulses were readily achieved.展开更多
'Giant' Cd Se/Cd S core/shell nanocrystals(NCs) were synthesized with thick Cd S shell(15 monolayers), and the x-ray diffraction(XRD) measurement indicates there is a zinc blende phase in the thick Cd S shell,...'Giant' Cd Se/Cd S core/shell nanocrystals(NCs) were synthesized with thick Cd S shell(15 monolayers), and the x-ray diffraction(XRD) measurement indicates there is a zinc blende phase in the thick Cd S shell, whereas it transformed into wurtzite phase under 5 min radiation with a 400 nm, 594 μJ∕cm2femtosecond(fs) laser beam.The evolution of the NCs’ spontaneous emission under the fs laser radiation was recorded with a Hamamatsu streak camera. The as-synthesized NCs exhibit an amplified spontaneous emission(ASE) at 530 nm, which comes from a bulk-like Cd S shell due to the interfacial potential barrier, which could slow down the relaxation of holes from the shell to the core. After being annealed by an fs laser, the ASE of the g-NCs is transferred from a bulk-like Cd S shell to a quantum-confined Cd Se core because the phase transformation determined with the XRD measurement could remove the interfacial barrier. Besides the ASE at 643 nm, two shorter-wavelength ASE peaks at 589 and 541 nm, corresponding to optical transitions of the second(1P) and third(1D) electron quantization shells of the Cd Se core, also appear, thus indicating that Auger recombination is effectively suppressed.展开更多
Although bulk endocytosis has been found in a number of neuronal and endocrine cells,the molecular mechanism and physiological function of bulk endocytosis remain elusive.In pancreatic beta cells,we have observed bulk...Although bulk endocytosis has been found in a number of neuronal and endocrine cells,the molecular mechanism and physiological function of bulk endocytosis remain elusive.In pancreatic beta cells,we have observed bulk-like endocytosis evoked both by flash photolysis and trains of depolarization.Bulk-like endocytosis is a clathrin-independent process that is facilitated by enhanced extracellular Ca^(2+) entry and suppressed by the inhibition of dynamin function.Moreover,defects in bulklike endocytosis are accompanied by hyperinsulinemia in primary beta cells dissociated from diabetic KKAy mice,which suggests that bulk-like endocytosis plays an important role in maintaining the exo-endocytosis balance and beta cell secretory capability.展开更多
Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite-like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(C...Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite-like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(CuBiI4) thin films directly on ITO substrate at room temperature, by utilizing a Bi-Cu alloy layer as precursor. X-ray diffraction and transmission electron microscopy(TEM) results verified the formation of well crystallized CuBiI4 thin films with [222] orientation. The transient photovoltage(TPV) analysis revealed that the CuBiI4 is an n-type semiconductor with a suitable band gap of ~1.81 eV, preferable to photoelectric conversion compared with CH3NH3PbI3. It is very interesting that the subsequent spin-coating process of the classical Spiro-MeOTAD organic solution with TBP and acetonitrile resulted in a dense and smooth CuBiI4:SpiroMeOTAD bulk-heterojunction film. The preliminarily fabricated simple sandwich structures of ITO/CuBiI4:Spiro-MeOTAD/Au hybrid solar cell devices displayed efficient photovoltaic performance with the PCE up to 1.119% of the best sample. The room temperature direct metal surface elemental reaction(DMSER) method may provide a new insight for all-inorganic lead free perovskite-like AaBbXx compounds and high performance photovoltaic devices.展开更多
基金supported by the National Research Foundation of Korea funded by the Korean Government(MSIT),South Korea(Grant Nos.NRF-2015R1A2A2A11000907 and NRF-2015R1A2A2A04006979)Ministry of Science and ICT(MSIT),Korea,under the Information Technology Research Center(ITRC)support program(IITP-2017-2015-0-00385),supervised by the Institute for Information and Communications Technology Promotion(IITP)
文摘The potential of bulk-like WTe2 particles for the realization of a passive Q-switch operating at the 1 μm wavelength was investigated. The WTe2 particles were prepared using a simple mechanical exfoliation method together with Scotch tape. By attaching bulk-like WTe2 particles, which remained on the top of the sticky surface of a small segment of the Scotch tape, to the flat side of a side-polished fiber, a saturable absorber（SA） was readily implemented. A strong saturable absorption was then readily obtained through an evanescent field interaction with the WTe2 particles. The modulation depth of the prepared SA was measured as ~2.18% at 1.03 μm. By incorporating the proposed SA into an all-fiberized ytterbium-doped fiber ring cavity, stable Qswitched pulses were readily achieved.
基金supported by the National Basic Research Program of China (973 Program, 2012CB921801)the Science and Technology Department of Jiang Su Province (BE2012163)the Scientific Research Foundation of Graduate School of Southeast University (YBJJ1443)
文摘'Giant' Cd Se/Cd S core/shell nanocrystals(NCs) were synthesized with thick Cd S shell(15 monolayers), and the x-ray diffraction(XRD) measurement indicates there is a zinc blende phase in the thick Cd S shell, whereas it transformed into wurtzite phase under 5 min radiation with a 400 nm, 594 μJ∕cm2femtosecond(fs) laser beam.The evolution of the NCs’ spontaneous emission under the fs laser radiation was recorded with a Hamamatsu streak camera. The as-synthesized NCs exhibit an amplified spontaneous emission(ASE) at 530 nm, which comes from a bulk-like Cd S shell due to the interfacial potential barrier, which could slow down the relaxation of holes from the shell to the core. After being annealed by an fs laser, the ASE of the g-NCs is transferred from a bulk-like Cd S shell to a quantum-confined Cd Se core because the phase transformation determined with the XRD measurement could remove the interfacial barrier. Besides the ASE at 643 nm, two shorter-wavelength ASE peaks at 589 and 541 nm, corresponding to optical transitions of the second(1P) and third(1D) electron quantization shells of the Cd Se core, also appear, thus indicating that Auger recombination is effectively suppressed.
基金supported by a grant from the National Natural Science Foundation of China(Grant No.30871225)a grant from Beijing Municipal Science and Technology Commission(Grant No.7121008)+1 种基金a grant from the Ministry of Science and Technology(Grant No.SQ2011SF11B01041)the fund from The Key Construction Program of the National“985”Project from the Department of Education of China to Peking University.
文摘Although bulk endocytosis has been found in a number of neuronal and endocrine cells,the molecular mechanism and physiological function of bulk endocytosis remain elusive.In pancreatic beta cells,we have observed bulk-like endocytosis evoked both by flash photolysis and trains of depolarization.Bulk-like endocytosis is a clathrin-independent process that is facilitated by enhanced extracellular Ca^(2+) entry and suppressed by the inhibition of dynamin function.Moreover,defects in bulklike endocytosis are accompanied by hyperinsulinemia in primary beta cells dissociated from diabetic KKAy mice,which suggests that bulk-like endocytosis plays an important role in maintaining the exo-endocytosis balance and beta cell secretory capability.
基金supported by the National Natural Science Foundation of China (21673200, 61504117 and U1604121)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province (144200510014)
文摘Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite-like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(CuBiI4) thin films directly on ITO substrate at room temperature, by utilizing a Bi-Cu alloy layer as precursor. X-ray diffraction and transmission electron microscopy(TEM) results verified the formation of well crystallized CuBiI4 thin films with [222] orientation. The transient photovoltage(TPV) analysis revealed that the CuBiI4 is an n-type semiconductor with a suitable band gap of ~1.81 eV, preferable to photoelectric conversion compared with CH3NH3PbI3. It is very interesting that the subsequent spin-coating process of the classical Spiro-MeOTAD organic solution with TBP and acetonitrile resulted in a dense and smooth CuBiI4:SpiroMeOTAD bulk-heterojunction film. The preliminarily fabricated simple sandwich structures of ITO/CuBiI4:Spiro-MeOTAD/Au hybrid solar cell devices displayed efficient photovoltaic performance with the PCE up to 1.119% of the best sample. The room temperature direct metal surface elemental reaction(DMSER) method may provide a new insight for all-inorganic lead free perovskite-like AaBbXx compounds and high performance photovoltaic devices.
