The effect of drive laser wavelength on the growth of ablative Rayleigh–Taylor instability(ARTI)in inertial confinemen fusion(ICF)is studied with two-dimensional numerical simulations.The results show that in the pla...The effect of drive laser wavelength on the growth of ablative Rayleigh–Taylor instability(ARTI)in inertial confinemen fusion(ICF)is studied with two-dimensional numerical simulations.The results show that in the plasma acceleration phase,shorter wavelengths lead to more efficien coupling between the laser and the kinetic energy of the implosion fluid Under the condition that the laser energy coupled to the implosion flui is constant,the ARTI growth rate decreases as the laser wavelength moves toward the extreme ultraviolet band,reaching its minimum value near λ=65 nm,and when the laser wavelength continuously moves toward the X-ray band,the ARTI growth rate increases rapidly.It is found that the results deviate from the theoretical ARTI growth rate.As the laser intensity benchmark increases,the position of the minimum ARTI growth rate shifts toward shorter wavelengths.As the initial sinusoidal perturbation wavenumber decreases,the position of the minimum ARTI growth rate shifts toward longer wavelengths.We believe that the conclusions drawn from the present simulations and analysis will help provide a better understanding of the ICF process and improve the theory of ARTI growth.展开更多
A self-pulsed Tm:GdScO_(3)laser was experimentally demonstrated by using a compact linear resonant cavity.When the pump power was 19.6 W,an average output power of 1771 m W was achieved from the self-pulsed Tm:GdScO_(...A self-pulsed Tm:GdScO_(3)laser was experimentally demonstrated by using a compact linear resonant cavity.When the pump power was 19.6 W,an average output power of 1771 m W was achieved from the self-pulsed Tm:GdScO_(3)laser with a pulse width of 158.1 ns and a pulse repetition frequency of 112.8 kHz,corresponding to an optical-to-optical conversion efficiency of 9.0%.Moreover,a single pulse energy of 15.7μJ and a pulse peak power of 99.3 W were acquired from the self-pulsed Tm:GdScO_(3)laser.This is,as we know,the first time that the self-pulsed laser output at 2-μm waveband range was obtained by utilizing a Tm:GdScO_(3)crystal so far.展开更多
The developing human and mouse teeth constitute an ideal model system to study the regulatory mechanism underlying organ growth control since their teeth share highly conserved and well-characterized developmental pro...The developing human and mouse teeth constitute an ideal model system to study the regulatory mechanism underlying organ growth control since their teeth share highly conserved and well-characterized developmental processes, and their developmental tempo varies notably. In the current study, we manipulated heterogenous recombination between human and mouse dental tissues and demonstrated that the dental mesenchyme dominates the tooth developmental tempo and FGF8 could be a critical player during this developmental process. Forced activation of FGF8 signaling in the dental mesenchyme of mice promoted cell proliferation, prevented cell apoptosis via p38 and perhaps PI3 K-Akt intracellular signaling,and impelled the transition of the cell cycle from G1-to S-phase in the tooth germ, resulting in the slowdown of the tooth developmental pace. Our results provide compelling evidence that extrinsic signals can profoundly affect tooth developmental tempo, and the dental mesenchymal FGF8 could be a pivotal factor in controlling the developmental pace in a non-cell-autonomous manner during mammalian odontogenesis.展开更多
Scale not only affects the taste and color ofwater,but also increases the risks of osteoporosis and cardiovascular diseases associated with drinking it.As a popular beverage,tea is rich many substances that have consi...Scale not only affects the taste and color ofwater,but also increases the risks of osteoporosis and cardiovascular diseases associated with drinking it.As a popular beverage,tea is rich many substances that have considerable potential for scale inhibition,including protein,tea polyphenols and organic acids.In this study,the effect of tea brewing on scale formationwas explored.It was found that the proteins,catechins and organic acids in tea leaves could be released when the green tea was brewed in water with sufficient hardness and alkalinity.The tea-released protein was able to provide carboxyl groups to chelate with calcium ions(Ca^(2+)),preventing the Ca^(2+)from reacting with the carbonate ions(CO_(3)^(2-)).The B rings of catechins were another important structure in the complexation of Ca^(2+)and magnesium ions(Mg2+).The carboxyl and hydroxyl groups on the organic acids was able to form fivemembered chelating rings with Ca^(2+)and Mg^(2+),resulting in a significant decrease in Ca^(2+)from 100.0 to 60.0 mg/L.Additionally,the hydrogen ions(H^(+))provided by the organic acids consumed and decreased the alkalinity of the water from 250.0 to 131.4 mg/L,leading to a remarkable reduction in pH from 8.93 to 7.73.It further prevented the bicarbonate(HCO_(3)^(-))from producing CO_(3)^(2−)when the water was heated.The reaction of the tea constituents with the hardness and alkalinity inhibited the formation of scale,leading to a significant decrease in turbidity from 10.6 to 1.4 NTU.Overall,this study provides information to help build towards an understanding of the scale inhibition properties of tea and the prospects of tea for anti-scaling in industrial applications.展开更多
The Front Variable Area Bypass Injector(FVABI)is a key to bypass ratio adjustment for a Variable Cycle Engine(VCE).In order to study the role of the FVABI with the Core Driven Fan Stage(CDFS)duct,firstly,the engine by...The Front Variable Area Bypass Injector(FVABI)is a key to bypass ratio adjustment for a Variable Cycle Engine(VCE).In order to study the role of the FVABI with the Core Driven Fan Stage(CDFS)duct,firstly,the engine bypass with the CDFS duct model and the equivalent engine bypass without the CDFS duct model are designed using the concept of a jet boundary line.By comparing the difference between airflow driving forces in the two engine bypass models,the quantitative effects of the injection from the CDFS duct on the mass flow rate of the engine bypass airflow are obtained under different combinations of pressure difference and area ratios.Then,the CDFS duct injection characteristic map is obtained through the typical experiment of the FVABI.Based on this map,the performance model of the FVABI is developed.Finally,the turbofan engine model with the Variable Inlet Guide Vane(VIGV),the First Variable Cycle Engine model(VCE1)with the CDFS duct and without the VIGV,and the Second Variable Cycle Engine model(VCE2)with the CDFS duct and VIGV are built.The gain on the engine bypass ratio adjustment range caused by the injection from the CDFS duct is clarified by comparing the three engine models.It is concluded that the bypass ratio adjustment range of the variable cycle engine with the FVABI is about twice that of the traditional turbofan engine.展开更多
Coherent combining of several low-energy few-cycle beams offers a reliable and feasible approach to producing fewcycle laser pulses with energies exceeding the multi-joule level.However,time synchronization and carrie...Coherent combining of several low-energy few-cycle beams offers a reliable and feasible approach to producing fewcycle laser pulses with energies exceeding the multi-joule level.However,time synchronization and carrier-envelope phase difference(ΔCEP)between pulses significantly affect the temporal waveform and intensity of the combined pulse,requiring precise measurement and control.Here,we propose a concise optical method based on the phase retrieval of spectral interference and quadratic function symmetry axis fitting to simultaneously measure the time synchronization andΔCEP between few-cycle pulses.The control precision of our coherent beam combining system can achieve a time delay stability within 42 as andΔCEP measurement precision of 40 mrad,enabling a maximum combining efficiency of 98.5%.This method can effectively improve the performance and stability of coherent beam combining systems for few-cycle lasers,which will facilitate the obtaining of high-quality few-cycle lasers with high energy.展开更多
We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 ...We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 W were acquired from the Tm, Ho:LuVO4 laser with the pump power of 14.55 W, corresponding to a pulse width of 2.89 μs,a pulse repetition rate of 71.84 kHz, and a pulse energy of about 6.70 μJ.展开更多
Laser-driven inertial confinement fusion(ICF)diagnostics play a crucial role in understanding the complex physical processes governing ICF and enabling ignition.During the ICF process,the interaction between the high-...Laser-driven inertial confinement fusion(ICF)diagnostics play a crucial role in understanding the complex physical processes governing ICF and enabling ignition.During the ICF process,the interaction between the high-power laser and ablation material leads to the formation of a plasma critical surface,which reflects a significant portion of the driving laser,reducing the efficiency of laser energy conversion into implosive kinetic energy.Effective diagnostic methods for the critical surface remain elusive.In this work,we propose a novel optical diagnostic approach to investigate the plasma critical surface.This method has been experimentally validated,providing new insights into the critical surface morphology and dynamics.This advancement represents a significant step forward in ICF diagnostic capabilities,with the potential to inform strategies for enhancing the uniformity of the driving laser and target surface,ultimately improving the efficiency of converting laser energy into implosion kinetic energy and enabling ignition.展开更多
As optical parametric chirped pulse amplification has been widely adopted for the generation of extreme intensity laser sources,nonlinear crystals of large aperture are demanded for high-energy amplifiers.Yttrium calc...As optical parametric chirped pulse amplification has been widely adopted for the generation of extreme intensity laser sources,nonlinear crystals of large aperture are demanded for high-energy amplifiers.Yttrium calcium oxyborate(YCa_(4)O(BO_(3))_(3),YCOB)is capable of being grown with apertures exceeding 100 mm,which makes it possible for application in systems of petawatt scale.In this paper,we experimentally demonstrated for the first time to our knowledge,an ultra-broadband non-collinear optical parametric amplifier with YCOB for petawatt-scale compressed pulse generation at 800 nm.Based on the SG-II 5 PW facility,amplified signal energy of approximately 40 J was achieved and pump-to-signal conversion efficiency was up to 42.3%.A gain bandwidth of 87 nm was realized and supported a compressed pulse duration of 22.3 fs.The near-field and wavefront aberration represented excellent characteristics,which were comparable with those achieved in lithium triborate-based amplifiers.These results verified the great potential for YCOB utilization in the future.展开更多
The formation of a moirésuperlattice is induced by the stacking of van der Waals(vdW)2D materials with a twist angle or small lattice mismatch.This superlattice functions as a periodic potential for electrons,for...The formation of a moirésuperlattice is induced by the stacking of van der Waals(vdW)2D materials with a twist angle or small lattice mismatch.This superlattice functions as a periodic potential for electrons,forming moiréflat bands with emerging quantum phenomena or highly correlated states.展开更多
The active/passive Q-switching operation of a 2 [tm a-cut Tm,Ho：YAP laser was experimentally demonstrated with an acousto-optical Q-switch/MoS2 saturable absorber mirror. The active Q-switch laser was operated for th...The active/passive Q-switching operation of a 2 [tm a-cut Tm,Ho：YAP laser was experimentally demonstrated with an acousto-optical Q-switch/MoS2 saturable absorber mirror. The active Q-switch laser was operated for the first time, to the best of our knowledge, with an average output power of 12.3 W and a maximum pulse energy of 10.3 mJ. The passive Q-switch laser was also the first acquired with an average output power of 3.3 W and per pulse energy of 23.31 μJ, and the beam quality factors of Mx^2 = 1.06 and My^2 = 1.06 were measured at the average output power of 2 W.展开更多
There is a rising prospective in harvesting energy from the environment,as in situ energy is required for the distributed sensors in the interconnected information society,among which the water flow energy is the most...There is a rising prospective in harvesting energy from the environment,as in situ energy is required for the distributed sensors in the interconnected information society,among which the water flow energy is the most potential candidate as a clean and abundant mechanical source.However,for microscale and unordered movement of water,achieving a sustainable direct-current generating device with high output to drive the load element is still challenging,which requires for further exploration.Herein,we propose a dynamic PN water junction generator with moving water sandwiched between two semiconductors,which outputs a sustainable direct-current voltage of 0.3 V and a current of 0.64μA.The mechanism can be attributed to the dynamic polarization process of water as moving dielectric medium in the dynamic PN water junction,under the Fermi level difference of two semiconductors.We further demonstrate an encapsulated portable power-generating device with simple structure and continuous direct-current voltage output of 0.11 V,which exhibits its promising potential application in the field of wearable devices and the IoTs.展开更多
Topological materials and topological phases have recently become a hot topic in condensed matter physics.In this work,we report an In-intercalated transition-metal dichalcogenide In_(x)TaSe_(2)(named 112 system),a to...Topological materials and topological phases have recently become a hot topic in condensed matter physics.In this work,we report an In-intercalated transition-metal dichalcogenide In_(x)TaSe_(2)(named 112 system),a topological nodal-line semimetal in the prep seffiffinffi ce of both charge density wave(CDW)and superconductivity.In the x=0.58 sample,the 2×√3 commensurate CDW(CCDW)and the 2×2 CCDW are observed below 116 and 77 K,respectively.Consistent with theoretical calculations,the spin–orbital coupling gives rise to two twofold-degenerate nodal rings(Weyl rings)connected by drumhead surface states,confirmed by angle-resolved photoemission spectroscopy.Our results suggest that the 2×2 CCDW ordering gaps out one Weyl ring in accordance with the CDW band folding,while the other Weyl ring remains gapless with intact surface states.In addition,superconductivity emerges at 0.91 K,with the upper critical field deviating from the s-wave behavior at low temperature,implying possibly unconventional superconductivity.Therefore,we think this type of the 112 system may possess abundant physical states and offer a platform to investigate the interplay between CDW,nontrivial band topology and superconductivity.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.12074399,12204500,and 12004403)the Key Projects of the Intergovernmental International Scientifi and Technological Innovation Cooperation(Grant No.2021YFE0116700)+1 种基金the Shanghai Natural Science Foundation(Grant No.20ZR1464400)the Shanghai Sailing Program(Grant No.22YF1455300)。
文摘The effect of drive laser wavelength on the growth of ablative Rayleigh–Taylor instability(ARTI)in inertial confinemen fusion(ICF)is studied with two-dimensional numerical simulations.The results show that in the plasma acceleration phase,shorter wavelengths lead to more efficien coupling between the laser and the kinetic energy of the implosion fluid Under the condition that the laser energy coupled to the implosion flui is constant,the ARTI growth rate decreases as the laser wavelength moves toward the extreme ultraviolet band,reaching its minimum value near λ=65 nm,and when the laser wavelength continuously moves toward the X-ray band,the ARTI growth rate increases rapidly.It is found that the results deviate from the theoretical ARTI growth rate.As the laser intensity benchmark increases,the position of the minimum ARTI growth rate shifts toward shorter wavelengths.As the initial sinusoidal perturbation wavenumber decreases,the position of the minimum ARTI growth rate shifts toward longer wavelengths.We believe that the conclusions drawn from the present simulations and analysis will help provide a better understanding of the ICF process and improve the theory of ARTI growth.
基金Project supported by the Key Research and Development Plan of Xinjiang Uygur Autonomous Region,China(Grant Nos.2022B01040 and 2022B01040-2)the Key Project of Heilongjiang Natural Science Foundation(Grant No.ZD2021F002)。
文摘A self-pulsed Tm:GdScO_(3)laser was experimentally demonstrated by using a compact linear resonant cavity.When the pump power was 19.6 W,an average output power of 1771 m W was achieved from the self-pulsed Tm:GdScO_(3)laser with a pulse width of 158.1 ns and a pulse repetition frequency of 112.8 kHz,corresponding to an optical-to-optical conversion efficiency of 9.0%.Moreover,a single pulse energy of 15.7μJ and a pulse peak power of 99.3 W were acquired from the self-pulsed Tm:GdScO_(3)laser.This is,as we know,the first time that the self-pulsed laser output at 2-μm waveband range was obtained by utilizing a Tm:GdScO_(3)crystal so far.
基金supported by the National Natural Science Foundation of China (81870739, 82001002, 81271102, 81771034)the Natural Science Foundation of Fujian Province (2019J01281, 2020J01180)。
文摘The developing human and mouse teeth constitute an ideal model system to study the regulatory mechanism underlying organ growth control since their teeth share highly conserved and well-characterized developmental processes, and their developmental tempo varies notably. In the current study, we manipulated heterogenous recombination between human and mouse dental tissues and demonstrated that the dental mesenchyme dominates the tooth developmental tempo and FGF8 could be a critical player during this developmental process. Forced activation of FGF8 signaling in the dental mesenchyme of mice promoted cell proliferation, prevented cell apoptosis via p38 and perhaps PI3 K-Akt intracellular signaling,and impelled the transition of the cell cycle from G1-to S-phase in the tooth germ, resulting in the slowdown of the tooth developmental pace. Our results provide compelling evidence that extrinsic signals can profoundly affect tooth developmental tempo, and the dental mesenchymal FGF8 could be a pivotal factor in controlling the developmental pace in a non-cell-autonomous manner during mammalian odontogenesis.
基金supported by the National Natural Science Foundation of China (No. 51978558)the National Key Research and Development Program of China (No. 2019YFD1100102-04)the Chemical Institute of Chemical Industry of Shaanxi Normal University,Open Project of State Key Laboratory of Urban Water Resource and Environment (No. ES202121)
文摘Scale not only affects the taste and color ofwater,but also increases the risks of osteoporosis and cardiovascular diseases associated with drinking it.As a popular beverage,tea is rich many substances that have considerable potential for scale inhibition,including protein,tea polyphenols and organic acids.In this study,the effect of tea brewing on scale formationwas explored.It was found that the proteins,catechins and organic acids in tea leaves could be released when the green tea was brewed in water with sufficient hardness and alkalinity.The tea-released protein was able to provide carboxyl groups to chelate with calcium ions(Ca^(2+)),preventing the Ca^(2+)from reacting with the carbonate ions(CO_(3)^(2-)).The B rings of catechins were another important structure in the complexation of Ca^(2+)and magnesium ions(Mg2+).The carboxyl and hydroxyl groups on the organic acids was able to form fivemembered chelating rings with Ca^(2+)and Mg^(2+),resulting in a significant decrease in Ca^(2+)from 100.0 to 60.0 mg/L.Additionally,the hydrogen ions(H^(+))provided by the organic acids consumed and decreased the alkalinity of the water from 250.0 to 131.4 mg/L,leading to a remarkable reduction in pH from 8.93 to 7.73.It further prevented the bicarbonate(HCO_(3)^(-))from producing CO_(3)^(2−)when the water was heated.The reaction of the tea constituents with the hardness and alkalinity inhibited the formation of scale,leading to a significant decrease in turbidity from 10.6 to 1.4 NTU.Overall,this study provides information to help build towards an understanding of the scale inhibition properties of tea and the prospects of tea for anti-scaling in industrial applications.
基金supported by the National Science and Technology Major Project of China (No. J2019-II-00070027)the China Academy of Launch Vehicle Technology Funding (No. CALT2023-07)
文摘The Front Variable Area Bypass Injector(FVABI)is a key to bypass ratio adjustment for a Variable Cycle Engine(VCE).In order to study the role of the FVABI with the Core Driven Fan Stage(CDFS)duct,firstly,the engine bypass with the CDFS duct model and the equivalent engine bypass without the CDFS duct model are designed using the concept of a jet boundary line.By comparing the difference between airflow driving forces in the two engine bypass models,the quantitative effects of the injection from the CDFS duct on the mass flow rate of the engine bypass airflow are obtained under different combinations of pressure difference and area ratios.Then,the CDFS duct injection characteristic map is obtained through the typical experiment of the FVABI.Based on this map,the performance model of the FVABI is developed.Finally,the turbofan engine model with the Variable Inlet Guide Vane(VIGV),the First Variable Cycle Engine model(VCE1)with the CDFS duct and without the VIGV,and the Second Variable Cycle Engine model(VCE2)with the CDFS duct and VIGV are built.The gain on the engine bypass ratio adjustment range caused by the injection from the CDFS duct is clarified by comparing the three engine models.It is concluded that the bypass ratio adjustment range of the variable cycle engine with the FVABI is about twice that of the traditional turbofan engine.
基金supported by the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(Grant No.2021YFE0116700)the National Natural Science Foundation of China(NSFC)(Grant Nos.12204500 and 12074399)+1 种基金the Shanghai Sailing Program(Grant No.22YF1455300)the Chinese Academy of Sciences(Grant Nos.XDA25020105,XDA25020103 and XDA25020101)。
文摘Coherent combining of several low-energy few-cycle beams offers a reliable and feasible approach to producing fewcycle laser pulses with energies exceeding the multi-joule level.However,time synchronization and carrier-envelope phase difference(ΔCEP)between pulses significantly affect the temporal waveform and intensity of the combined pulse,requiring precise measurement and control.Here,we propose a concise optical method based on the phase retrieval of spectral interference and quadratic function symmetry axis fitting to simultaneously measure the time synchronization andΔCEP between few-cycle pulses.The control precision of our coherent beam combining system can achieve a time delay stability within 42 as andΔCEP measurement precision of 40 mrad,enabling a maximum combining efficiency of 98.5%.This method can effectively improve the performance and stability of coherent beam combining systems for few-cycle lasers,which will facilitate the obtaining of high-quality few-cycle lasers with high energy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61775053,51572053,51777046,and 61705140)
文摘We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 W were acquired from the Tm, Ho:LuVO4 laser with the pump power of 14.55 W, corresponding to a pulse width of 2.89 μs,a pulse repetition rate of 71.84 kHz, and a pulse energy of about 6.70 μJ.
基金supported by the National Natural Science Foundation of China(NSFC)(12074399,12204500 and 12004403)the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(2021YFE0116700)+1 种基金the Shanghai Natural Science Foundation(20ZR1464400)the Shanghai Sailing Program(22YF1455300).
文摘Laser-driven inertial confinement fusion(ICF)diagnostics play a crucial role in understanding the complex physical processes governing ICF and enabling ignition.During the ICF process,the interaction between the high-power laser and ablation material leads to the formation of a plasma critical surface,which reflects a significant portion of the driving laser,reducing the efficiency of laser energy conversion into implosive kinetic energy.Effective diagnostic methods for the critical surface remain elusive.In this work,we propose a novel optical diagnostic approach to investigate the plasma critical surface.This method has been experimentally validated,providing new insights into the critical surface morphology and dynamics.This advancement represents a significant step forward in ICF diagnostic capabilities,with the potential to inform strategies for enhancing the uniformity of the driving laser and target surface,ultimately improving the efficiency of converting laser energy into implosion kinetic energy and enabling ignition.
基金partially supported by the Shanghai Natural Science Foundation(No.20ZR1464400)the National Natural Science Foundation of China(NSFC)(Nos.12074399,12204500 and 12004403)+4 种基金the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(No.2021YFE0116700)the Shanghai Sailing Program(No.22YF1455300)the International Partnership Program of the Chinese Academy of Sciences(No.181231KYSB20170022)the Chinese Academy of Sciences(Nos.CXJJ-21S015,XDA25020311 and XDA25020105)NSAF(No.U1930126)
文摘As optical parametric chirped pulse amplification has been widely adopted for the generation of extreme intensity laser sources,nonlinear crystals of large aperture are demanded for high-energy amplifiers.Yttrium calcium oxyborate(YCa_(4)O(BO_(3))_(3),YCOB)is capable of being grown with apertures exceeding 100 mm,which makes it possible for application in systems of petawatt scale.In this paper,we experimentally demonstrated for the first time to our knowledge,an ultra-broadband non-collinear optical parametric amplifier with YCOB for petawatt-scale compressed pulse generation at 800 nm.Based on the SG-II 5 PW facility,amplified signal energy of approximately 40 J was achieved and pump-to-signal conversion efficiency was up to 42.3%.A gain bandwidth of 87 nm was realized and supported a compressed pulse duration of 22.3 fs.The near-field and wavefront aberration represented excellent characteristics,which were comparable with those achieved in lithium triborate-based amplifiers.These results verified the great potential for YCOB utilization in the future.
基金financially supported by the Natural Science Foundation of Zhejiang Province(grants LD22E010001 and LR23E030002)the National Natural Science Foundation of China(grant 62375243)the Fundamental Research Funds for the Central Universities(50672087).
文摘The formation of a moirésuperlattice is induced by the stacking of van der Waals(vdW)2D materials with a twist angle or small lattice mismatch.This superlattice functions as a periodic potential for electrons,forming moiréflat bands with emerging quantum phenomena or highly correlated states.
基金National Natural Science Foundation of China(NSFC)(61378029,61775053,51572053,51777046)Science Foundation for Outstanding Youths of Heilongjiang Province(JC2016016)Science Foundation for Youths of Heilongjiang Province(QC2017078)
文摘The active/passive Q-switching operation of a 2 [tm a-cut Tm,Ho：YAP laser was experimentally demonstrated with an acousto-optical Q-switch/MoS2 saturable absorber mirror. The active Q-switch laser was operated for the first time, to the best of our knowledge, with an average output power of 12.3 W and a maximum pulse energy of 10.3 mJ. The passive Q-switch laser was also the first acquired with an average output power of 3.3 W and per pulse energy of 23.31 μJ, and the beam quality factors of Mx^2 = 1.06 and My^2 = 1.06 were measured at the average output power of 2 W.
基金S.S.Lin thanks the support from the National Natural Science Foundation of China(No.51202216,51502264,61774135)K.H.Liu thanks the support from the Beijing Natural Science Foundation(JQ19004)+4 种基金Beijing Excellent Talents Training Support(2017000026833ZK11)Bureau of Industry and Information Technology of Shenzhen(No.201901161512)Key-Area Research and Development Program of Guangdong Province(Grant Nos.2019B010931001,2020B010189001)Project funded by the China Postdoctoral Science Foundation(2019M660001)Postdoctoral Innovative Personnel Support Program(BX20180013).
文摘There is a rising prospective in harvesting energy from the environment,as in situ energy is required for the distributed sensors in the interconnected information society,among which the water flow energy is the most potential candidate as a clean and abundant mechanical source.However,for microscale and unordered movement of water,achieving a sustainable direct-current generating device with high output to drive the load element is still challenging,which requires for further exploration.Herein,we propose a dynamic PN water junction generator with moving water sandwiched between two semiconductors,which outputs a sustainable direct-current voltage of 0.3 V and a current of 0.64μA.The mechanism can be attributed to the dynamic polarization process of water as moving dielectric medium in the dynamic PN water junction,under the Fermi level difference of two semiconductors.We further demonstrate an encapsulated portable power-generating device with simple structure and continuous direct-current voltage output of 0.11 V,which exhibits its promising potential application in the field of wearable devices and the IoTs.
基金the National Key R&D Program of the China(2016YFA0300402,2014CB648400,and 2016YFA0300203)the National Natural Science Foundation of China(11774305 and 11274006)the Fundamental Research Funds for the Central Universities of China。
文摘Topological materials and topological phases have recently become a hot topic in condensed matter physics.In this work,we report an In-intercalated transition-metal dichalcogenide In_(x)TaSe_(2)(named 112 system),a topological nodal-line semimetal in the prep seffiffinffi ce of both charge density wave(CDW)and superconductivity.In the x=0.58 sample,the 2×√3 commensurate CDW(CCDW)and the 2×2 CCDW are observed below 116 and 77 K,respectively.Consistent with theoretical calculations,the spin–orbital coupling gives rise to two twofold-degenerate nodal rings(Weyl rings)connected by drumhead surface states,confirmed by angle-resolved photoemission spectroscopy.Our results suggest that the 2×2 CCDW ordering gaps out one Weyl ring in accordance with the CDW band folding,while the other Weyl ring remains gapless with intact surface states.In addition,superconductivity emerges at 0.91 K,with the upper critical field deviating from the s-wave behavior at low temperature,implying possibly unconventional superconductivity.Therefore,we think this type of the 112 system may possess abundant physical states and offer a platform to investigate the interplay between CDW,nontrivial band topology and superconductivity.
