This paper investigates the effects of spontaneously induced coherence on absorption properties in a nearly equispaced three-level ladder-type system driven by two coherent fields. It find that the absorption properti...This paper investigates the effects of spontaneously induced coherence on absorption properties in a nearly equispaced three-level ladder-type system driven by two coherent fields. It find that the absorption properties of this system with the probe field applied on the lower transition can be significantly modified if this coherence is optimized. In the case of small spontaneous decay rate in the upper excited state, it finds that such coherence does not destroy the electromagnetically induced transparency （EIT）. Nevertheless, the absorption peak on both sides of zero detuning and the linewidth of absorption line become larger and narrower than those in the case corresponding to the effects of spontaneously induced coherence; while in the case of large decay rate, it finds that, instead of EIT with low resonant absorption, a sharp absorption peak at resonance appears. That is, electromagnetically induced absorption in the nearly equispaced ladder-type system can occur due to such coherent effects.展开更多
A theoretical model is developed for calculating the eigenmodes of the multi-gap resonant cavity. The structure of concern is a kind of ladder-type circuit, offering the advantages of easy fabrication, high characteri...A theoretical model is developed for calculating the eigenmodes of the multi-gap resonant cavity. The structure of concern is a kind of ladder-type circuit, offering the advantages of easy fabrication, high characteristic impedance （R/Q）, and thermal capacity in the millimeter wave to THz regime. The eigenfunction expansion method is used to establish the field expressions for the gaps and the coupling region. Then, the match conditions at the interface are employed, which leads to a group of complicate boundary equations in the form of an infinite series. To facilitate the mathematical treatments and perform a highly efficient calculation, these boundary equations are transformed into the algebraic forms through the matrix representations. Finally, the concise dispersion equation is obtained. The roots of the dispersion equation include both the axial modes in the gaps, which include the fundamental and the high-order modes, and the cavity modes in the coupling region. Extensive numerical results are presented and the behaviors of the multi-gap resonant cavity are examined.展开更多
Summary： The purpose of the present study was to observe the structure and functional change of the bone-coating-prosthesis interface in vivo and to evaluate the histocompatibility of self-made prosthetic femoral com...Summary： The purpose of the present study was to observe the structure and functional change of the bone-coating-prosthesis interface in vivo and to evaluate the histocompatibility of self-made prosthetic femoral components in the body and the degree of their bonding with the surrounding bone tissues as well as their stability. Six mature beagle dogs underwent bilateral hip replacement with prosthetic femur components. Three groups were established in terms of different coating of prothesis （four joints in each group）： atmosphere （A） plasma-sprayed pure titanium （Ti） prosthetic joint with hydroxyapatite （HA） coating （HA＋Ti＋A group）; vacuum （V） plasma-sprayed pure Ti prosthetic joint with HA coating （HA＋Ti＋V group）; vacuum plasma-sprayed pure Ti prosthetic joint with Ti-HA stepped coating （Ti＋HAG＋Ti＋V group）. The hip joints were functionally evaluated, and subjected to X-ray examination, biomechanics inspection, and histological examination. As a result, X-ray imaging revealed all prosthetic joints were in a good location and no dislocation of joint was found. Shear strength of interface was significantly higher in Ti＋HAG＋Ti＋V group than in HA＋Ti＋V group （P〈0.05） and HA＋Ti＋A group （P〈0.05） at 28th week. Histological examination showed the amount of newborn bone in Ti＋HAG＋Ti＋V group was more than in HA＋Ti＋V group and HA＋Ti＋A group after 28 weeks. It was suggested that vacuum plasma-sprayed pure Ti prosthetic joint with TI-HA stepped coating could improve the bonding capacity of bone-prosthesis, enhance the stability of prosthesis, and increase the fixion of prosthetic femoral components because of better bone growth. This new type of biological material in prosthetic femoral components holds promises for application in clinical practice.展开更多
The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave a...The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave approximation （RWA）. It is shown that population transfer is mainly determined by the Rabi frequency （strength） of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.展开更多
One important subject in the field of all-polymer solar cells (all-PSCs) is the exploration of electron-deficient building blocks with optimized physicochemical properties to promote the performance of polymer accepto...One important subject in the field of all-polymer solar cells (all-PSCs) is the exploration of electron-deficient building blocks with optimized physicochemical properties to promote the performance of polymer acceptors. Here, two ladder-type heteroheptacene-containing small-molecule acceptors with branched 2-octyldodecyl or 2-hexyldecyl side-chains are synthesized and polymerized with the thiophene co-monomer to afford polymer acceptors (PW-OD and PW-HD) with strong near-infrared absorption. Experimental results reveal that the alkyl chain length has a large impact on the molecular packing behavior of the resulting polymers, which in turn affects their light-absorbing and charge transport properties, and thus the photovoltaic performance of the final devices. When blended with the polymer donor PM6, PW-HD-based all-PSCs deliver a higher power conversion efficiency (PCE) of 9.12% compared to the PCE of 6.47% for the PW-OD-based all-PSCs, mainly due to its more ordered inter-chain packing and more favorable blend morphology. This work provides a promising building block for the development of high-performance narrow-bandgap polymer acceptors and highlights the importance of side-chain substitution in optimizing the photovoltaic performance of polymer acceptors.展开更多
A scheme is presented to generate even-photon state based on resonant interaction between ladder-type three-level atoms with a single-mode field. In the scheme, a sequence of suitably prepared ladder-type three-level ...A scheme is presented to generate even-photon state based on resonant interaction between ladder-type three-level atoms with a single-mode field. In the scheme, a sequence of suitably prepared ladder-type three-level atoms are orderly sent through a single-mode cavity initiaJly in vacuum state. The detection of a J1 the atoms in the ground states collapses the cavity to the desired state. The scheme is based on the resonant interaction of atoms with the cavity, and thus the required interaction time can be greatly shortened. This is important in view of decoherence.展开更多
Driven by the goal of“carbon neutrality”and“emission peak”,effectively controlling system carbon emissions has become significantly important to governments around the world.To this end,a novel two-stage low-carbo...Driven by the goal of“carbon neutrality”and“emission peak”,effectively controlling system carbon emissions has become significantly important to governments around the world.To this end,a novel two-stage low-carbon economic scheduling framework that considers the coordinated optimization of ladder-type carbon trading and integrated demand response(IDR)is proposed in this paper for the integrated energy system(IES),where the first stage determines the energy consumption plan of users by leveraging the price-based electrical-heat IDR.In contrast,the second stage minimizes the system total cost to optimize the outputs of generations with consideration of the uncertainty of renewables.In addition,to fully exploit the system’s emission reduction potential,a carbon trading cost model with segmented CO_(2) emission intervals is built by introducing a reward-penalty ladder-type carbon trading mechanism,and the flexible thermal comfort elasticity of customers is taken into account by putting forward a predicted mean vote index on the load side.The CPLEX optimizer resolves the two-stage model,and the study results on a modified IES situated in North China show the proposed model can effectively reduce carbon emissions and guarantee economical efficiency operation of the system.展开更多
Double resonance optical pumping spectroscopy has an outstanding advantage of high signal-to-noise ratio, thus having potential applications in precision measurement. With the counter propagated 780nm and 776nm laser ...Double resonance optical pumping spectroscopy has an outstanding advantage of high signal-to-noise ratio, thus having potential applications in precision measurement. With the counter propagated 780nm and 776nm laser beams acting on a rubidium vapor cell, the high resolution spectrum of 5S1/2 - 5P3/2 - 5D5/2 ladder-type transition of ST Rb atoms is obtained by monitoring the population of the 5S1/2 ground state. The dependence of the spectroscopy lineshape on the probe and coupling fields are comprehensively studied in theory and experiment. This research is helpful for measurement of fundamental physical constants by high resolution spectroscopy.展开更多
In northern China,thermal power units(TPUs)are important in improving the penetration level of renewable energy.In such areas,the potentials of coordinated dispatch of renewable energy sources(RESs)and TPUs can be bet...In northern China,thermal power units(TPUs)are important in improving the penetration level of renewable energy.In such areas,the potentials of coordinated dispatch of renewable energy sources(RESs)and TPUs can be better realized,if RESs and TPUs connected to the power grid at the same point of common coupling(PCC)are dispatched as a coupled system.Firstly,the definition of the coupled system is introduced,followed by an analysis on its characteristics.Secondly,based on the operation characteristics of deep peak regulation(DPR)of TPUs in the coupled system,the constraint of the ladder-type ramping rate applicable for day-ahead dispatch is proposed,and the corresponding flexible spinning reserve constraint is further established.Then,considering these constraints and peak regulation ancillary services,a day-ahead optimal dispatch model of the coupled system is established.Finally,the operational characteristics and advantages of the coupled system are analyzed in several case studies based on a real-world power grid in Liaoning province,China.The numerical results show that the coupled system can further improve the economic benefits of RESs and TPUs under the existing policies.展开更多
An experimental investigation of two-color polarization spectroscopy(TCPS) is presented based on the cesium 6 S1/2– 6P3/2– 8S1/2(852.3 nm + 794.6 nm) ladder-type system in a room-temperature vapor cell. The dependen...An experimental investigation of two-color polarization spectroscopy(TCPS) is presented based on the cesium 6 S1/2– 6P3/2– 8S1/2(852.3 nm + 794.6 nm) ladder-type system in a room-temperature vapor cell. The dependency of line shapes of TCPS on the power of a 852.3 nm pump and a 794.6 nm probe laser is measured in detail, and we confirm that the linewidth of TCPS in a counter-propagating configuration between the pump and probe laser beams is obviously narrower than that of a co-propagating configuration, due to the atomic coherence effect. It is helpful for laser stabilization of the excited state transition using TCPS without frequency modulation.展开更多
A carbon-oxygen-bridged ladder-type donor unit （CO5） was invented and prepared via an ＂intramolecu- lar demethanolization cyclization＂ approach. Its single crystal structure indicates enhanced planarity compared w...A carbon-oxygen-bridged ladder-type donor unit （CO5） was invented and prepared via an ＂intramolecu- lar demethanolization cyclization＂ approach. Its single crystal structure indicates enhanced planarity compared with the carbon-bridged analogue indacenodithiophene （IDT）. Owing to the stronger electron-donating capability of CO5 than IDT, CO5-based donor and acceptor materials show narrower bandgaps. A donor-acceptor （D-A） copolymer donor （PCO5TPD） and an A-D-A nonfullerene acceptor （COSIC） demonstrated higher performance than IDT-based counterparts, PIDTTPD and IDTIC, respec-tively. The better performance of CO5-based materials results from their stronger light-harvesting capability and higher charge-carrier mobilities.展开更多
We present a new design strategy to synthesize ladder-type thienoacenaphthopyrazine(TAP)-based monomers through two different coupling reactions from starting material 5,6-dibromoacenaphthylene-1,2-dione.By bringing v...We present a new design strategy to synthesize ladder-type thienoacenaphthopyrazine(TAP)-based monomers through two different coupling reactions from starting material 5,6-dibromoacenaphthylene-1,2-dione.By bringing varous electron-deficient groups together(such as five-membered aromatic rings,pyrazine,fluorine,and thiadiazols),this new family of molecules exhibits good stability in ambient conditions and easily tunes the electronic,photophysical and film-forming properties of polymers.The unique molecular shape with its extendedπ-conjugated backbone perpendicular to the polymer chain,offers a remarkable platform for the development of a semiconducting polymer with rare geometry.The planar and enlarged conjugated backbone enables TAP-based copolymers PTAP1 and PTAP2 to exhibit distinguishing solubility properties that are different from small-molecule-based polymers,indicating the advantages of novel ladder-type monomers.Their insolubility in chloroform supports orthogonal solvent processing to fabricate layer-by-layer organic solar cells(LBL-OSCs).Owing to its shorterπ–πstacking distance,higher hole mobility,and more favorable phase separation caused bymultifluorine substitution,polymer PTAP1-based LBL-OSC exhibits the highest efficiency of 17.14%by using Y6-BO as the electron acceptor while the efficiency for the PTAP2-based device is 14.20%.This high efficiency indicates the tremendous potential of these novel building units.展开更多
Considerable effort has been devoted to the design of silicon-containingπ-conjugated materials for application in optoelectronic devices and fluorescent bioimaging.However,the synthesis and spectroscopic tuning of ge...Considerable effort has been devoted to the design of silicon-containingπ-conjugated materials for application in optoelectronic devices and fluorescent bioimaging.However,the synthesis and spectroscopic tuning of germanium(Ge)-conjugated systems are challenging because of the paucity of synthetically useful methods.Herein,we report a simple and effective method of lithium naphthalenide-induced intramolecular cyclization to construct architecturally diverse Ge-containingπ-conjugated molecules,including benzogermoles and their ladder-type derivatives,with high yields of up to 92%.The photophysical properties of these molecules can befinely controlled by the introduction of electrondonating or-withdrawing substituents,and intense luminescence ranging from deep-blue to red regions in the solid state was observed.A quantitative model based on the Hammett constant against the luminescence wavelength showed a good linear correlation,allowing us to reliably predict and design luminescent materials with specific properties for applications.Notably,Ge-bridged ladder-type derivatives exhibited high photoluminescence and efficient deep-blue electroluminescence with good color purity.We believe this study will open a new avenue to organogermanium chemistry and offers greater flexibility for electronic structural tuning.展开更多
A 1470 nm＋ 852 nm two-color（TC） cesium（Cs） magneto-optical trap（MOT） with a 6S_（1/2）-6P_（3/2）-7S_（1/2） laddertype system is proposed and experimentally investigated. To the best of our knowledge, it is t...A 1470 nm＋ 852 nm two-color（TC） cesium（Cs） magneto-optical trap（MOT） with a 6S_（1/2）-6P_（3/2）-7S_（1/2） laddertype system is proposed and experimentally investigated. To the best of our knowledge, it is the first report about the 1470 nm ＋ 852 nm Cs TC-MOT. One of the three pairs of the 852 nm cooling and trapping beams（CTBs） in a conventional Cs MOT is replaced with a pair of the 1470 nm CTBs. Thus, the TC-MOT partially employs the optical radiation forces from photon scattering of the 6P_（3∕2）（F＇= 5）-7S_（1∕2）（F＇＇= 4） excited-state transition（1470 nm）. This TC-MOT can cool and trap Cs atoms on both the red-and blue-detuning sides of the twophoton resonance. This work may have applications in cooling and trapping of atoms using inconvenient wavelengths and background-free detection of cold and trapped Cs atoms.展开更多
Short-axis substitution, as an effective way to change the optical and electronic properties of the organic semiconductors for organic photovoltaics(OPVs), is a readily approach to modify non-fullerene acceptors, espe...Short-axis substitution, as an effective way to change the optical and electronic properties of the organic semiconductors for organic photovoltaics(OPVs), is a readily approach to modify non-fullerene acceptors, especially for the linear fused rings system. Here, two new fused-ring electron acceptors(CBT-IC and SBT-IC) were designed and developed by short-axis modification based on the dithienyl[1,2-b:4,5-b′]benzodithiophene(BDCPDT) system. Combined with a medium bandgap polymer donor J71, both of the OPV devices exhibit high power conversion efficiency(PCE) over 11%, and ～70% external quantum efficiencies. To better understand how this kind of substitution affects the BDCPDT based acceptors, a comparative analysis is also made with the the plain acceptor BDT-IC without this modification. We believe this work could disclose the great potential and the versatility of BDCPDT block and also enlighten other ladder-type series for further optimization.展开更多
基金Project supported by the National Science Foundation of China （Grant No 10234030） and the Natural Science Foundation of Shanghai, China （Grant No 03ZR14102）.
文摘This paper investigates the effects of spontaneously induced coherence on absorption properties in a nearly equispaced three-level ladder-type system driven by two coherent fields. It find that the absorption properties of this system with the probe field applied on the lower transition can be significantly modified if this coherence is optimized. In the case of small spontaneous decay rate in the upper excited state, it finds that such coherence does not destroy the electromagnetically induced transparency （EIT）. Nevertheless, the absorption peak on both sides of zero detuning and the linewidth of absorption line become larger and narrower than those in the case corresponding to the effects of spontaneously induced coherence; while in the case of large decay rate, it finds that, instead of EIT with low resonant absorption, a sharp absorption peak at resonance appears. That is, electromagnetically induced absorption in the nearly equispaced ladder-type system can occur due to such coherent effects.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61222110 and 60971073)
文摘A theoretical model is developed for calculating the eigenmodes of the multi-gap resonant cavity. The structure of concern is a kind of ladder-type circuit, offering the advantages of easy fabrication, high characteristic impedance （R/Q）, and thermal capacity in the millimeter wave to THz regime. The eigenfunction expansion method is used to establish the field expressions for the gaps and the coupling region. Then, the match conditions at the interface are employed, which leads to a group of complicate boundary equations in the form of an infinite series. To facilitate the mathematical treatments and perform a highly efficient calculation, these boundary equations are transformed into the algebraic forms through the matrix representations. Finally, the concise dispersion equation is obtained. The roots of the dispersion equation include both the axial modes in the gaps, which include the fundamental and the high-order modes, and the cavity modes in the coupling region. Extensive numerical results are presented and the behaviors of the multi-gap resonant cavity are examined.
基金supported by the Natural Science Foundation of Hubei Province of China(No.2012FFB02431)
文摘Summary： The purpose of the present study was to observe the structure and functional change of the bone-coating-prosthesis interface in vivo and to evaluate the histocompatibility of self-made prosthetic femoral components in the body and the degree of their bonding with the surrounding bone tissues as well as their stability. Six mature beagle dogs underwent bilateral hip replacement with prosthetic femur components. Three groups were established in terms of different coating of prothesis （four joints in each group）： atmosphere （A） plasma-sprayed pure titanium （Ti） prosthetic joint with hydroxyapatite （HA） coating （HA＋Ti＋A group）; vacuum （V） plasma-sprayed pure Ti prosthetic joint with HA coating （HA＋Ti＋V group）; vacuum plasma-sprayed pure Ti prosthetic joint with Ti-HA stepped coating （Ti＋HAG＋Ti＋V group）. The hip joints were functionally evaluated, and subjected to X-ray examination, biomechanics inspection, and histological examination. As a result, X-ray imaging revealed all prosthetic joints were in a good location and no dislocation of joint was found. Shear strength of interface was significantly higher in Ti＋HAG＋Ti＋V group than in HA＋Ti＋V group （P〈0.05） and HA＋Ti＋A group （P〈0.05） at 28th week. Histological examination showed the amount of newborn bone in Ti＋HAG＋Ti＋V group was more than in HA＋Ti＋V group and HA＋Ti＋A group after 28 weeks. It was suggested that vacuum plasma-sprayed pure Ti prosthetic joint with TI-HA stepped coating could improve the bonding capacity of bone-prosthesis, enhance the stability of prosthesis, and increase the fixion of prosthetic femoral components because of better bone growth. This new type of biological material in prosthetic femoral components holds promises for application in clinical practice.
基金supported by National Basic Research Program of China (Grant No 2006CB806003)the Natural Science Foundation of Shandong Province,China (Grant No Y2006A21)+1 种基金the National Natural Science Foundation of China (Grant No 10675076)State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,China
文摘The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave approximation （RWA）. It is shown that population transfer is mainly determined by the Rabi frequency （strength） of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.
基金supported by the National Natural Science Foundation of China(Nos.52130306,22075287 and 22101285)the Nature Science Foundation of Fujian Province(No.2021J01515)the Program of Youth Innovation Promotion Association CAS(No.2021299).
文摘One important subject in the field of all-polymer solar cells (all-PSCs) is the exploration of electron-deficient building blocks with optimized physicochemical properties to promote the performance of polymer acceptors. Here, two ladder-type heteroheptacene-containing small-molecule acceptors with branched 2-octyldodecyl or 2-hexyldecyl side-chains are synthesized and polymerized with the thiophene co-monomer to afford polymer acceptors (PW-OD and PW-HD) with strong near-infrared absorption. Experimental results reveal that the alkyl chain length has a large impact on the molecular packing behavior of the resulting polymers, which in turn affects their light-absorbing and charge transport properties, and thus the photovoltaic performance of the final devices. When blended with the polymer donor PM6, PW-HD-based all-PSCs deliver a higher power conversion efficiency (PCE) of 9.12% compared to the PCE of 6.47% for the PW-OD-based all-PSCs, mainly due to its more ordered inter-chain packing and more favorable blend morphology. This work provides a promising building block for the development of high-performance narrow-bandgap polymer acceptors and highlights the importance of side-chain substitution in optimizing the photovoltaic performance of polymer acceptors.
基金The project supported by the Science Foundation of the Education Department of Fujian Province of China under Grant No.JB06043the Development Funds of Fuzhou University under Grant No.2007-XY-15
文摘A scheme is presented to generate even-photon state based on resonant interaction between ladder-type three-level atoms with a single-mode field. In the scheme, a sequence of suitably prepared ladder-type three-level atoms are orderly sent through a single-mode cavity initiaJly in vacuum state. The detection of a J1 the atoms in the ground states collapses the cavity to the desired state. The scheme is based on the resonant interaction of atoms with the cavity, and thus the required interaction time can be greatly shortened. This is important in view of decoherence.
基金supported by the State Grid Shandong Electric Power Company Economic and Technical Research Institute Project(SGSDJY00GPJS2100135).
文摘Driven by the goal of“carbon neutrality”and“emission peak”,effectively controlling system carbon emissions has become significantly important to governments around the world.To this end,a novel two-stage low-carbon economic scheduling framework that considers the coordinated optimization of ladder-type carbon trading and integrated demand response(IDR)is proposed in this paper for the integrated energy system(IES),where the first stage determines the energy consumption plan of users by leveraging the price-based electrical-heat IDR.In contrast,the second stage minimizes the system total cost to optimize the outputs of generations with consideration of the uncertainty of renewables.In addition,to fully exploit the system’s emission reduction potential,a carbon trading cost model with segmented CO_(2) emission intervals is built by introducing a reward-penalty ladder-type carbon trading mechanism,and the flexible thermal comfort elasticity of customers is taken into account by putting forward a predicted mean vote index on the load side.The CPLEX optimizer resolves the two-stage model,and the study results on a modified IES situated in North China show the proposed model can effectively reduce carbon emissions and guarantee economical efficiency operation of the system.
基金Supported by the National Key R&D Program of China under Grant No 2017YFA0304203the National Natural Science Foundation of China under Grant Nos 61575116,61705122,61728502,91736209 and 11434007+2 种基金the Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China under Grant No IRT13076the Program for Sanjin Scholars of Shanxi Province,the Applied Basic Research Project of Shanxi Province under Grant No 201701D221004the Fund for Shanxi ‘1331 Project’ Key Subjects Construction
文摘Double resonance optical pumping spectroscopy has an outstanding advantage of high signal-to-noise ratio, thus having potential applications in precision measurement. With the counter propagated 780nm and 776nm laser beams acting on a rubidium vapor cell, the high resolution spectrum of 5S1/2 - 5P3/2 - 5D5/2 ladder-type transition of ST Rb atoms is obtained by monitoring the population of the 5S1/2 ground state. The dependence of the spectroscopy lineshape on the probe and coupling fields are comprehensively studied in theory and experiment. This research is helpful for measurement of fundamental physical constants by high resolution spectroscopy.
基金supported in part by the National Key Research and Development Program of China(No.2019YFB1505400).
文摘In northern China,thermal power units(TPUs)are important in improving the penetration level of renewable energy.In such areas,the potentials of coordinated dispatch of renewable energy sources(RESs)and TPUs can be better realized,if RESs and TPUs connected to the power grid at the same point of common coupling(PCC)are dispatched as a coupled system.Firstly,the definition of the coupled system is introduced,followed by an analysis on its characteristics.Secondly,based on the operation characteristics of deep peak regulation(DPR)of TPUs in the coupled system,the constraint of the ladder-type ramping rate applicable for day-ahead dispatch is proposed,and the corresponding flexible spinning reserve constraint is further established.Then,considering these constraints and peak regulation ancillary services,a day-ahead optimal dispatch model of the coupled system is established.Finally,the operational characteristics and advantages of the coupled system are analyzed in several case studies based on a real-world power grid in Liaoning province,China.The numerical results show that the coupled system can further improve the economic benefits of RESs and TPUs under the existing policies.
基金financially supported by the National Natural Science Foundation of China(Nos.11774210,11104172,and 61575112)the National Key Research and Development Program of China(No.2017YFA0304502)
文摘An experimental investigation of two-color polarization spectroscopy(TCPS) is presented based on the cesium 6 S1/2– 6P3/2– 8S1/2(852.3 nm + 794.6 nm) ladder-type system in a room-temperature vapor cell. The dependency of line shapes of TCPS on the power of a 852.3 nm pump and a 794.6 nm probe laser is measured in detail, and we confirm that the linewidth of TCPS in a counter-propagating configuration between the pump and probe laser beams is obviously narrower than that of a co-propagating configuration, due to the atomic coherence effect. It is helpful for laser stabilization of the excited state transition using TCPS without frequency modulation.
基金supported by the National Natural Science Foundation of China (U1401244, 21374025, 21372053, 21572041, and 51503050)the National Natural Science Foundation of China (51673218) for financial support+2 种基金the National Key Research and Development Program of China (2017YFA0206600)the State Key Laboratory of Luminescent Materials and Devices (2016-skllmd-05)the Youth Association for Promoting Innovation (CAS)
文摘A carbon-oxygen-bridged ladder-type donor unit （CO5） was invented and prepared via an ＂intramolecu- lar demethanolization cyclization＂ approach. Its single crystal structure indicates enhanced planarity compared with the carbon-bridged analogue indacenodithiophene （IDT）. Owing to the stronger electron-donating capability of CO5 than IDT, CO5-based donor and acceptor materials show narrower bandgaps. A donor-acceptor （D-A） copolymer donor （PCO5TPD） and an A-D-A nonfullerene acceptor （COSIC） demonstrated higher performance than IDT-based counterparts, PIDTTPD and IDTIC, respec-tively. The better performance of CO5-based materials results from their stronger light-harvesting capability and higher charge-carrier mobilities.
基金This work was supported by the National Natural Science Foundation of China(grant no.22179076)the Fund for Zhujiang Young Scholar(grant no.18220203)+1 种基金the Natural Science Foundation of Guangdong Province(grant no.2022A1515011803)the Department of Education of Guangdong Province(grant nos.2021KCXTD032 and 2019KCXTD007).
文摘We present a new design strategy to synthesize ladder-type thienoacenaphthopyrazine(TAP)-based monomers through two different coupling reactions from starting material 5,6-dibromoacenaphthylene-1,2-dione.By bringing varous electron-deficient groups together(such as five-membered aromatic rings,pyrazine,fluorine,and thiadiazols),this new family of molecules exhibits good stability in ambient conditions and easily tunes the electronic,photophysical and film-forming properties of polymers.The unique molecular shape with its extendedπ-conjugated backbone perpendicular to the polymer chain,offers a remarkable platform for the development of a semiconducting polymer with rare geometry.The planar and enlarged conjugated backbone enables TAP-based copolymers PTAP1 and PTAP2 to exhibit distinguishing solubility properties that are different from small-molecule-based polymers,indicating the advantages of novel ladder-type monomers.Their insolubility in chloroform supports orthogonal solvent processing to fabricate layer-by-layer organic solar cells(LBL-OSCs).Owing to its shorterπ–πstacking distance,higher hole mobility,and more favorable phase separation caused bymultifluorine substitution,polymer PTAP1-based LBL-OSC exhibits the highest efficiency of 17.14%by using Y6-BO as the electron acceptor while the efficiency for the PTAP2-based device is 14.20%.This high efficiency indicates the tremendous potential of these novel building units.
基金We acknowledge financial support by the National Natural Science Foundation of China(no.21871072 for H.L.)and the Program for High-Level Innovation Team in Universities of Zhejiang Province.
文摘Considerable effort has been devoted to the design of silicon-containingπ-conjugated materials for application in optoelectronic devices and fluorescent bioimaging.However,the synthesis and spectroscopic tuning of germanium(Ge)-conjugated systems are challenging because of the paucity of synthetically useful methods.Herein,we report a simple and effective method of lithium naphthalenide-induced intramolecular cyclization to construct architecturally diverse Ge-containingπ-conjugated molecules,including benzogermoles and their ladder-type derivatives,with high yields of up to 92%.The photophysical properties of these molecules can befinely controlled by the introduction of electrondonating or-withdrawing substituents,and intense luminescence ranging from deep-blue to red regions in the solid state was observed.A quantitative model based on the Hammett constant against the luminescence wavelength showed a good linear correlation,allowing us to reliably predict and design luminescent materials with specific properties for applications.Notably,Ge-bridged ladder-type derivatives exhibited high photoluminescence and efficient deep-blue electroluminescence with good color purity.We believe this study will open a new avenue to organogermanium chemistry and offers greater flexibility for electronic structural tuning.
基金supported by the National Natural Science Foundation of China under Grant Nos.61475091,11274213,and 61227902
文摘A 1470 nm＋ 852 nm two-color（TC） cesium（Cs） magneto-optical trap（MOT） with a 6S_（1/2）-6P_（3/2）-7S_（1/2） laddertype system is proposed and experimentally investigated. To the best of our knowledge, it is the first report about the 1470 nm ＋ 852 nm Cs TC-MOT. One of the three pairs of the 852 nm cooling and trapping beams（CTBs） in a conventional Cs MOT is replaced with a pair of the 1470 nm CTBs. Thus, the TC-MOT partially employs the optical radiation forces from photon scattering of the 6P_（3∕2）（F＇= 5）-7S_（1∕2）（F＇＇= 4） excited-state transition（1470 nm）. This TC-MOT can cool and trap Cs atoms on both the red-and blue-detuning sides of the twophoton resonance. This work may have applications in cooling and trapping of atoms using inconvenient wavelengths and background-free detection of cold and trapped Cs atoms.
基金supported by the National Natural Science Foundation of China (61575136, 21504062, 91633301, 91433117, 21572152)the National Key R&D Program of China (2016YFB0400700)+3 种基金the Collaborative Innovation Center of Suzhou Nano Science and Technology (Nano-CIC)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the “111” Project of the State Administration of Foreign Experts Affairs of Chinathe Yunnan Provincial Research Funds on College-Enterprise Collaboration (2015IB016)
文摘Short-axis substitution, as an effective way to change the optical and electronic properties of the organic semiconductors for organic photovoltaics(OPVs), is a readily approach to modify non-fullerene acceptors, especially for the linear fused rings system. Here, two new fused-ring electron acceptors(CBT-IC and SBT-IC) were designed and developed by short-axis modification based on the dithienyl[1,2-b:4,5-b′]benzodithiophene(BDCPDT) system. Combined with a medium bandgap polymer donor J71, both of the OPV devices exhibit high power conversion efficiency(PCE) over 11%, and ～70% external quantum efficiencies. To better understand how this kind of substitution affects the BDCPDT based acceptors, a comparative analysis is also made with the the plain acceptor BDT-IC without this modification. We believe this work could disclose the great potential and the versatility of BDCPDT block and also enlighten other ladder-type series for further optimization.
