Organic photothermal materials based on conjugated structures hold great potential for solar harvesting but are often constrained by narrow absorption and limited solar-thermal conversion efficiency.A general molecula...Organic photothermal materials based on conjugated structures hold great potential for solar harvesting but are often constrained by narrow absorption and limited solar-thermal conversion efficiency.A general molecular design strategy that can simultaneously broaden absorption and enhance nonradiative decay remains elusive.Here,we pioneer a quinoid-donor-acceptor(Q-D-A)architecture specifically tailored for photothermal applications.Incorporating quinoidal unit into a D-A polymer backbone yields the novel polymer PAQM-TBz,which exhibits a reinforced backbone planarity,intensifiedπ-πinteractions,and enhanced diradical character compared with its D-A analogue,P2T-TBz.These synergistic features enable broadband absorption(400-1500 nm)and rapid nonradiative relaxation,yielding an outstanding photothermal conversion efficiency of 80.6%under 808 nm laser irradiation—nearly twice that of P2T-TBz.Under 1.0 kW m^(-2) simulated sunlight,PAQM-TBz achieves a record-high solar-to-vapor efficiency of 97.3%with an evaporation rate of 1.41 kg m^(-2) h^(-1).It also generates a peak thermoelectric voltage of 126.1 mV,and in integrated water-electricity cogeneration,attains an evaporation rate of 1.28 kg m^(-2) h^(-1) and a voltage 95.8 mV,ranking among the highest for organic materials.This work establishes the Q-D-A strategy as a transformative platform for advanced solar-thermal energy conversion and multifunctional solar-harvesting applications.展开更多
This paper presents experimental results concerning the effect of dielectric type on ozone concentration and the efficiency of its generation in plasma reactor with two mesh electrodes.Three types of dielectric solid ...This paper presents experimental results concerning the effect of dielectric type on ozone concentration and the efficiency of its generation in plasma reactor with two mesh electrodes.Three types of dielectric solid were used in the study; glass, micanite and Kapton insulating foil. The experiments were conducted for voltage ranges from 2.3 to 13 k V. A plasma reactor equipped with two 0.3×0.3 mm^2 mesh electrodes made of acid resistant AISI 304 mesh was used in the experiments. The influence of the dielectric type on the concentration and efficiency of ozone generation was described. The resulting maximum concentration of the ozone was about 2.70–9.30 g O3 m^-3, depending on the dielectrics used. The difference between the maximum and the minimum ozone concentration depends on the dielectric used,this accounts for 70% at the variance. The reactor capacity has also been described in the paper; total Ct and dielectric capacitance Cd depending on the dielectric used and its thickness.展开更多
This study investigates the Maximum Power Point Tracking(MPPT)control method of offshore windphotovoltaic hybrid power generation system with offshore crane-assisted.A new algorithm of Global Fast Integral Sliding Mod...This study investigates the Maximum Power Point Tracking(MPPT)control method of offshore windphotovoltaic hybrid power generation system with offshore crane-assisted.A new algorithm of Global Fast Integral Sliding Mode Control(GFISMC)is proposed based on the tip speed ratio method and sliding mode control.The algorithm uses fast integral sliding mode surface and fuzzy fast switching control items to ensure that the offshore wind power generation system can track the maximum power point quickly and with low jitter.An offshore wind power generation system model is presented to verify the algorithm effect.An offshore off-grid wind-solar hybrid power generation systemis built in MATLAB/Simulink.Compared with other MPPT algorithms,this study has specific quantitative improvements in terms of convergence speed,tracking accuracy or computational efficiency.Finally,the improved algorithm is further analyzed and carried out by using Yuankuan Energy’s ModelingTech semi-physical simulation platform.The results verify the feasibility and effectiveness of the improved algorithm in the offshore wind-solar hybrid power generation system.展开更多
The switchless reluctance motor’s non-permanent magnet structure design ensures its high reliability in the marine environment;thus,it is a feasible solution for the generator of a sea wave power generation system.Ho...The switchless reluctance motor’s non-permanent magnet structure design ensures its high reliability in the marine environment;thus,it is a feasible solution for the generator of a sea wave power generation system.However,the corresponding thrust density and efficiency remain insufficient.This study focused on a new type of flat linear switched reluctance motor(LSRM),using the finite element software to establish a structural model,and optimized the design with the goal of improving the efficiency and energy density.The entropy method was adopted for sensitivity stratification to objectively select weights to avoid the influence of subjectively selected different proportional weights on the optimization results.Based on the entropy method,the sensitivity of different structural parameters was stratified,and the simulated annealing algorithm,response surface method,and single parameter scanning method were combined for optimization.Finally,the optimal structural size parameters of the motor were determined.Based on the two-dimensional finite element method,to simulate the electromagnetic performance of the reluctance motor under different operating conditions,such as thrust,loss,and efficiency,changes in motor performance before and after optimization were compared to verify the high power generation efficiency and energy density of the optimized linear motor.展开更多
Tomato (Solanum lycopersicum) is the leading vegetable crop worldwide and an essential component of a healthy diet (Lin et al., 2014; Du et al., 2017). Fruit color is regarded as one of the most important commercial t...Tomato (Solanum lycopersicum) is the leading vegetable crop worldwide and an essential component of a healthy diet (Lin et al., 2014; Du et al., 2017). Fruit color is regarded as one of the most important commercial traits in tomato (The Tomato Genome Consortium, 2012). Consumers in different regions have different color preferences. For example, European and American consumers prefer red tomatoes, while pink tomatoes are more pop- ular in Asia countries, particularly in China and Japan (Ballester et al., 2010; Lin et al., 2014). However, most of tomato breeding ma- terials are red-fruited, thus the generation of pink-fruited materials is very important for Asian tomato production. Metabolomics and genetics studies demonstrate that the pink trait results from the absence of yellow-colored flavonoid naringenin chalcone (NarCh) in the peels,and is controlled by the monogenic recessive yellow(y)lOCUS(Adato et a1..2009;Ballester et a1..2OLO).展开更多
Generation of mouse models carrying a defined point mutation,especially disease-related point mutations,is of considerable interest for research in biology and medicine.The standard method based on embryonic stem cell...Generation of mouse models carrying a defined point mutation,especially disease-related point mutations,is of considerable interest for research in biology and medicine.The standard method based on embryonic stem cell（ESC）-mediated homologous recombination（HR）is time-and labor-consuming.展开更多
The geochemical analysis and experimental simulation are comprehensively used to systematically study the hydrocarbon generation material,organic matter enrichment and hydrocarbon generation model of Paleogene source ...The geochemical analysis and experimental simulation are comprehensively used to systematically study the hydrocarbon generation material,organic matter enrichment and hydrocarbon generation model of Paleogene source rock in the Western Qaidam Depression,Qaidam Basin,NW China.Three main factors result in low TOC values of saline lacustrine source rock of the Qaidam Basin:relatively poor nutrient supply inhibits the algal bloom,too fast deposition rate causes the dilution of organic matter,and high organic matter conversion efficiency causes the low residual organic carbon.For this type of hydrogen-rich organic matter,due to the reduction of organic carbon during hydrocarbon generation,TOC needs to be restored based on maturity before evaluating organic matter abundance.The hydrocarbon generation of saline lacustrine source rocks of the Qaidam Basin is from two parts:soluble organic matter and insoluble organic matter.The soluble organic matter is inherited from organisms and preserved in saline lacustrine basins.It generates hydrocarbons during low-maturity stage,and the formed hydrocarbons are rich in complex compounds such as NOS,and undergo secondary cracking to form light components in the later stage;the hydrocarbon generation model of insoluble organic matter conforms to the traditional“Tissot”model,with an oil generation peak corresponding to Ro of 1.0%.展开更多
We investigate the intensity and efficiency of a compressed echo, which is important in arbitrary waveform generation（AWG）. A new model of compressed echo is proposed based on the optical Bloch equations, which expo...We investigate the intensity and efficiency of a compressed echo, which is important in arbitrary waveform generation（AWG）. A new model of compressed echo is proposed based on the optical Bloch equations, which exposes much more detailed parameters than the conventional model, such as the time delay of the chirp lasers, the nature of the rare-earth-iondoped crystal, etc. According to the novel model of compressed echo, we find that reducing the time delay of the chirp lasers and scanning the lasers around the center frequency of the inhomogeneously broadened spectrum, while utilizing a crystal with larger coherence time and excitation lifetime can improve the compressed echo＇s intensity and efficiency. The theoretical analysis is validated by numerical simulations.展开更多
We report the first demonstration of high-efficiency ultraviolet(UV)pulse generation in a resonance-free anti-resonant hollow-core fiber(AR-HCF).Using the wet-etching technique,we successfully reduced the cladding-tub...We report the first demonstration of high-efficiency ultraviolet(UV)pulse generation in a resonance-free anti-resonant hollow-core fiber(AR-HCF).Using the wet-etching technique,we successfully reduced the cladding-tube wall thickness of the AR-HCF to 115 nm,thereby eliminating all cladding-induced structural resonances between the near-infrared pump and the deep UV wavelengths.This structural modification fundamentally suppresses competing conversion to other phase-matching points induced by structural resonances and mitigates the pump spectral broadening limitation,achieving a UV conversion efficiency as high as 12%—twice that of previous demonstrations in gas-filled AR-HCFs.This UV conversion efficiency is comparable to that of meter-scale gas-filled capillaries that require pump pulse energy of hundreds of microjoules while also maintaining the AR-HCF's inherent advantages of centimeter-scale compactness and low pump energy at the few microjoule level.展开更多
A numerical simulation method based on CFD has been established to simulate the fully coupled motion for an atten-uator-type wave energy converter(WEC).Based on this method,a detailed parametric analysis has been cond...A numerical simulation method based on CFD has been established to simulate the fully coupled motion for an atten-uator-type wave energy converter(WEC).Based on this method,a detailed parametric analysis has been conducted to investigate the design of the rafts.The effects of different parameters(wave parameters,structural parameters and PTO parameters)on the hydrodynamic characteristics of the attenuator-type WEC were studied in detail.The results show that in terms of wave parameters,there is an optimal wave period,which makes the relative pitching angle amplitude of the WEC reach the maximum,and the increase of wave height is conducive to the relative pitching angle amplitude of wave energy.Under different wave conditions,the relative pitch angle of the parallelogram raft device is the maximum.In terms of structural parameters,the parallelogram attenuator-type device has the optimal values in different relative directions,different distances and different apex angle,which makes the relative motion amplitude of the device reach the maximum,and the spacing and the apex angle have influence on the motion frequency of the device,while the relative direction has almost no influence on it.In terms of PTO parameters,there is an optimal damping coefficient,which makes the power generation efficiency of the WEC reach the maximum.The research results provide a valuable reference for future research and design of the attenuator-type WEC.展开更多
Energy-efficient electrolytic hydrogen generation is highly desired but still remains challenging.In this work,we demonstrate that a Cu_(3)P nanoarray on copper foam(Cu_(3)P/CF)behaves as a high-performance electrocat...Energy-efficient electrolytic hydrogen generation is highly desired but still remains challenging.In this work,we demonstrate that a Cu_(3)P nanoarray on copper foam(Cu_(3)P/CF)behaves as a high-performance electrocatalyst for hydrazine oxidation reaction(HzOR)in alkaline electrolytes.A full electrolytic system employing Cu_(3)P/CF as both an anode for HzOR and a cathode for hydrogen evolution reaction drives 100 mA cm^(-2)at a voltage of 0.72 V in 1.0 M KOH aqueous solution with 0.5 M hydrazine.It also demonstrates high long-term stability.展开更多
For offshore hydraulic drive wind turbines,the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted.A low-speed high-torque radial piston pump is designed to replace the traditio...For offshore hydraulic drive wind turbines,the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted.A low-speed high-torque radial piston pump is designed to replace the traditional fixed pump with a particular focus on its low-speed performance.The pump is characterized by small internal leakage at low wind speeds and high volumetric efficiency,which is beneficial to improve the power generation efficiency of the system.A new linear control method based on the PID algorithm and feedforward compensation was proposed to obtain the constant speed output control of variable motor at low wind speed.With the model for wind turbine and fixed pump-variable motor main drive system,the system was simulated and experimentally proved to verify the feasibility and anti-interference performance of the system control method at low wind speeds.A promising outcome was obtained on the response characteristics of system power and efficiency at low wind speeds.This can be a powerful technical support for the normal ustility of hydraulic drive wind turbines.展开更多
Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial struc...Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial structures.However,the nonlinear conversion efficiency is generally limited by the angular dispersion of optical resonances especially in nonparaxial photonics.Here,we propose a metagrating realizing a quasi-bound-state in the continuum in a flat band to dramatically improve the third harmonic generation(THG)efficiency.A superior operating angular range is achieved based on the interlayer and intralayer couplings,which are introduced by breaking the mirror symmetry of the metagrating.We demonstrate the relation of angular dispersion between the nonlinear and linear responses at different incident angles.We also elucidate the mechanism of these offaxis flat-band-based nonlinear conversions through different mode decomposition.Our scheme provides a robust and analytical way for nonparaxial nonlinear generation and paves the way for further applications such as wide-angle nonlinear information transmission and enhanced nonlinear generation under tight focusing.展开更多
Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suff...Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suffciently high second-harmonic generation(SHG)effciencies coupled to wide transparency ranges and high laser damage thresholds.A series of new hydrous rare-earth iodates RE(IO_(3))_(3)·(H_(2)O)(RE=Y 1,Eu 2)and La_(2)(IO_(3))_(6)(H_(2)O)(3)have been synthesized through facile hydrothermal methods.1 and 2 are isostructural,crystallizing in the polar space group P21,while 3 crystallizes in the polar space group Pc.1-3 feature three-dimensional(3D)frameworks composed of alternately connected corner-shared dis torted[REO_(x)]polyhedra(RE=Y,Eu,and La;x=8,9)and[IO_(3)]^(−)groups.Optical studies showed that 1–3 exhibit good NLO properties,including strong SHG intensities(3.0×(1),4.5×(2),and 1.5×KH_(2)PO_(4)(3)),large band gaps(4.12(1),4.36(2),and 4.24 eV(3),with 2 possessing the largest band gap among the known SHG-active rare-earth-based iodates,high laser damage thresholds(LDT)(53×(1),43×(2),and 44×AgGaS_(2)(3)),and wide transparency ranges(ca.3.0–11.3μm)in the mid-IR region covering two criti cal IR transparency windows;1–3 are therefore potential candidate NLO materials.Density functional theory calculations on 1–3 confirm that their strong SHG responses and large band gaps are mainly derived from the synergistic effect of[IO_(3)]^(−)groups and rare-earth oxide polyhedra[REOx]in their 3D frameworks.We conclude that the introduction of rare-earth cations with moderate electropositivity into iodates may optimize the balance between SHG effciency and optical band gaps,the key requirement for high-performance NLO materials for practical applications.展开更多
In the quest for organic–inorganic metal halides(OIMHs)that harmoniously combine large second harmonic generation(SHG)efficiency with broad bandgaps,our study introduces a series of noncentrosymmetric and polar piper...In the quest for organic–inorganic metal halides(OIMHs)that harmoniously combine large second harmonic generation(SHG)efficiency with broad bandgaps,our study introduces a series of noncentrosymmetric and polar piperazine zinc halides,(C_(4)H_(11)N_(2))ZnX_(3)(X=Cl,Br,I).The distinct influence of halide anion size on the configuration of ZnNX_(3)tetrahedra is uncovered,revealing a design principle for enhancing SHG activity and manipulating bandgap characteristics.Specifically,(C_(4)H_(11)N_(2))ZnCl_(3)is the first example of deep-ultraviolet(deep-UV)nonlinear optical(NLO)OIMHs,with UV transparency lower than 190 nm and moderate SHG effect,0.8 times KH_(2)PO_(4)(KDP).Meanwhile,compared with(C_(4)H_(11)N_(2))ZnI_(3)(2.1 times KDP,4.52 eV),(C_(4)H_(11)N_(2))ZnBr_(3)boasts a widened bandgap of 5.53 eV while maintaining a striking SHG response(2.5 times KDP),representing a pinnacle in the SHG-bandgap balance among OIMHs with Eg exceeding 5.0 eV.Computational analyses underscore the critical roles of halide orbitals and ZnNX_(3)distortions in dictating SHG efficiency,with increasing halide polarizability correlating with heightened SHG contributions.This study paves the way for a novel approach to designing short-UV NLO crystals based on OIMHs.展开更多
A computer generated holographic stereogram based on the wavefront recording plane （WRP） is presented. A WRP closed to the parallax image plane is introduced to record the complex amplitude in a small region for eac...A computer generated holographic stereogram based on the wavefront recording plane （WRP） is presented. A WRP closed to the parallax image plane is introduced to record the complex amplitude in a small region for each point in the parallax image. By using three times of fast Fourier transform （FFT） to execute the Fresnel dif- fraction calculation between the WRP and the holographic stereogram plane, the object wave contributing to the hologram pattern can be achieved. The computation complexity of the proposed approach is dramatically reduced. The results show that the calculation time can be decreased by more than one order of magnitude.展开更多
We systematically study the optimization of highly efficient terahertz（THz） generation in lithium niobate（LN）crystal pumped by 800 nm laser pulses with 30 fs pulse duration. At room temperature, we obtain a record...We systematically study the optimization of highly efficient terahertz（THz） generation in lithium niobate（LN）crystal pumped by 800 nm laser pulses with 30 fs pulse duration. At room temperature, we obtain a record optical-to-THz energy conversion efficiency of 0.43% by chirping the pump laser pulses. Our method provides a new technique for producing millijoule THz radiation in LN via optical rectification driven by joule-level Ti：sapphire laser systems, which deliver sub-50-fs pulse durations.展开更多
We report the investigation on the performance of an amplification assisted difference frequency generation(AA-DFG) system driven by pulsed pump and continuous-wave primary signal lasers. A monolithic tandem lithium n...We report the investigation on the performance of an amplification assisted difference frequency generation(AA-DFG) system driven by pulsed pump and continuous-wave primary signal lasers. A monolithic tandem lithium niobate superlattice was employed as the nonlinear crystal with a uniform grating section for the DFG process, followed by a chirp section for the optical parametric amplification process. The impacts of pump pulse shape, primary signal power, input beam diameter, and crystal structure on the pump-to-idler conversion efficiency of the AA-DFG system were comprehensively studied by numerically solving the coupled wave equations. It is concluded that square pump pulse and high primary signal power are beneficial to high pump-to-idler conversion efficiency. In addition, tighter input beam focus and smaller DFG length proportion could redeem the reduction in conversion efficiency resulting from wider acceptance bandwidths for the input lasers. We believe that such systems combining the merits of high stability inherited from cavity-free configuration and high efficiency attributed from the cascaded nonlinear conversion should be of great interest to a wide community,especially when the pulse shaping technique is incorporated.展开更多
A new structure for efficient and cost-effective L-band amplified spontaneous emission (ASE) generation was experimentally investigated and demonstrated using a C/L-band coupler, an optical mirror, and a fiber Bragg g...A new structure for efficient and cost-effective L-band amplified spontaneous emission (ASE) generation was experimentally investigated and demonstrated using a C/L-band coupler, an optical mirror, and a fiber Bragg grating (FBG). The proposed structure has about 1.5 dB increase of the power around 1570 nm compared with conventional one. Various structures for power enhancement were also considered.展开更多
We demonstrate the generation of non-classical photon pairs in a warm S-Rb atomic vapor （＇ell with no buffer gas or polarization preserving coatings via spontaneous four-wave mixing. We obtain the photon pairs with ...We demonstrate the generation of non-classical photon pairs in a warm S-Rb atomic vapor （＇ell with no buffer gas or polarization preserving coatings via spontaneous four-wave mixing. We obtain the photon pairs with a 1/e correlation time of 40 ns and the violation of Cauchy-Sehwartz inequality by a factor of 23 - 3. This provides a convenient and efficient method to generate photon pair sources based on an atomic ensemble.展开更多
基金supported by the National Natural Science Foundation of China(52363021 and 22305050)Science and Technology Foundation of Guizhou Province(QKHJC-ZK[2024]Key 002).
文摘Organic photothermal materials based on conjugated structures hold great potential for solar harvesting but are often constrained by narrow absorption and limited solar-thermal conversion efficiency.A general molecular design strategy that can simultaneously broaden absorption and enhance nonradiative decay remains elusive.Here,we pioneer a quinoid-donor-acceptor(Q-D-A)architecture specifically tailored for photothermal applications.Incorporating quinoidal unit into a D-A polymer backbone yields the novel polymer PAQM-TBz,which exhibits a reinforced backbone planarity,intensifiedπ-πinteractions,and enhanced diradical character compared with its D-A analogue,P2T-TBz.These synergistic features enable broadband absorption(400-1500 nm)and rapid nonradiative relaxation,yielding an outstanding photothermal conversion efficiency of 80.6%under 808 nm laser irradiation—nearly twice that of P2T-TBz.Under 1.0 kW m^(-2) simulated sunlight,PAQM-TBz achieves a record-high solar-to-vapor efficiency of 97.3%with an evaporation rate of 1.41 kg m^(-2) h^(-1).It also generates a peak thermoelectric voltage of 126.1 mV,and in integrated water-electricity cogeneration,attains an evaporation rate of 1.28 kg m^(-2) h^(-1) and a voltage 95.8 mV,ranking among the highest for organic materials.This work establishes the Q-D-A strategy as a transformative platform for advanced solar-thermal energy conversion and multifunctional solar-harvesting applications.
文摘This paper presents experimental results concerning the effect of dielectric type on ozone concentration and the efficiency of its generation in plasma reactor with two mesh electrodes.Three types of dielectric solid were used in the study; glass, micanite and Kapton insulating foil. The experiments were conducted for voltage ranges from 2.3 to 13 k V. A plasma reactor equipped with two 0.3×0.3 mm^2 mesh electrodes made of acid resistant AISI 304 mesh was used in the experiments. The influence of the dielectric type on the concentration and efficiency of ozone generation was described. The resulting maximum concentration of the ozone was about 2.70–9.30 g O3 m^-3, depending on the dielectrics used. The difference between the maximum and the minimum ozone concentration depends on the dielectric used,this accounts for 70% at the variance. The reactor capacity has also been described in the paper; total Ct and dielectric capacitance Cd depending on the dielectric used and its thickness.
基金supported by the 2022 Sanya Science and Technology Innovation Project,China(No.2022KJCX03)the Sanya Science and Education Innovation Park,Wuhan University of Technology,China(Grant No.2022KF0028)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City,China(Grant No.2021JJLH0036).
文摘This study investigates the Maximum Power Point Tracking(MPPT)control method of offshore windphotovoltaic hybrid power generation system with offshore crane-assisted.A new algorithm of Global Fast Integral Sliding Mode Control(GFISMC)is proposed based on the tip speed ratio method and sliding mode control.The algorithm uses fast integral sliding mode surface and fuzzy fast switching control items to ensure that the offshore wind power generation system can track the maximum power point quickly and with low jitter.An offshore wind power generation system model is presented to verify the algorithm effect.An offshore off-grid wind-solar hybrid power generation systemis built in MATLAB/Simulink.Compared with other MPPT algorithms,this study has specific quantitative improvements in terms of convergence speed,tracking accuracy or computational efficiency.Finally,the improved algorithm is further analyzed and carried out by using Yuankuan Energy’s ModelingTech semi-physical simulation platform.The results verify the feasibility and effectiveness of the improved algorithm in the offshore wind-solar hybrid power generation system.
基金This work is supported by the National Natural Science Foundation of China(52077141)the Natural Science Foundation of Liaoning Province(2021-YQ-09)the Liaoning Bai Qian Wan Talents Program,China。
文摘The switchless reluctance motor’s non-permanent magnet structure design ensures its high reliability in the marine environment;thus,it is a feasible solution for the generator of a sea wave power generation system.However,the corresponding thrust density and efficiency remain insufficient.This study focused on a new type of flat linear switched reluctance motor(LSRM),using the finite element software to establish a structural model,and optimized the design with the goal of improving the efficiency and energy density.The entropy method was adopted for sensitivity stratification to objectively select weights to avoid the influence of subjectively selected different proportional weights on the optimization results.Based on the entropy method,the sensitivity of different structural parameters was stratified,and the simulated annealing algorithm,response surface method,and single parameter scanning method were combined for optimization.Finally,the optimal structural size parameters of the motor were determined.Based on the two-dimensional finite element method,to simulate the electromagnetic performance of the reluctance motor under different operating conditions,such as thrust,loss,and efficiency,changes in motor performance before and after optimization were compared to verify the high power generation efficiency and energy density of the optimized linear motor.
基金supported by the National Key Research and Development Program of China (2016YFD0100500 and 2016YFD0101703)the National Natural Science Foundation of China (Nos. 31601759 and 31471881)+1 种基金the Ministry of Agriculture of China (2016ZX08009-003-001)the Tai-Shan Scholar Program from the Shandong Provincial Government
文摘Tomato (Solanum lycopersicum) is the leading vegetable crop worldwide and an essential component of a healthy diet (Lin et al., 2014; Du et al., 2017). Fruit color is regarded as one of the most important commercial traits in tomato (The Tomato Genome Consortium, 2012). Consumers in different regions have different color preferences. For example, European and American consumers prefer red tomatoes, while pink tomatoes are more pop- ular in Asia countries, particularly in China and Japan (Ballester et al., 2010; Lin et al., 2014). However, most of tomato breeding ma- terials are red-fruited, thus the generation of pink-fruited materials is very important for Asian tomato production. Metabolomics and genetics studies demonstrate that the pink trait results from the absence of yellow-colored flavonoid naringenin chalcone (NarCh) in the peels,and is controlled by the monogenic recessive yellow(y)lOCUS(Adato et a1..2009;Ballester et a1..2OLO).
基金supported by the Ministry of Science and Technology of China (2014CB964803 and 2015AA020307)the National Natural Science Foundation of China (Nos. 31530048, 31601163 and 81672117)+1 种基金he Chinese Academy of Sciences (XDB19010204 and QYZDJ-SSW-SMC023)the Shanghai Municipal Commission for Science and Technology(16JC1420500, 17JC1400900 and 17140901500)
文摘Generation of mouse models carrying a defined point mutation,especially disease-related point mutations,is of considerable interest for research in biology and medicine.The standard method based on embryonic stem cell（ESC）-mediated homologous recombination（HR）is time-and labor-consuming.
基金Supported by the PetroChina Science and Technology Project(2021DJ1808).
文摘The geochemical analysis and experimental simulation are comprehensively used to systematically study the hydrocarbon generation material,organic matter enrichment and hydrocarbon generation model of Paleogene source rock in the Western Qaidam Depression,Qaidam Basin,NW China.Three main factors result in low TOC values of saline lacustrine source rock of the Qaidam Basin:relatively poor nutrient supply inhibits the algal bloom,too fast deposition rate causes the dilution of organic matter,and high organic matter conversion efficiency causes the low residual organic carbon.For this type of hydrogen-rich organic matter,due to the reduction of organic carbon during hydrocarbon generation,TOC needs to be restored based on maturity before evaluating organic matter abundance.The hydrocarbon generation of saline lacustrine source rocks of the Qaidam Basin is from two parts:soluble organic matter and insoluble organic matter.The soluble organic matter is inherited from organisms and preserved in saline lacustrine basins.It generates hydrocarbons during low-maturity stage,and the formed hydrocarbons are rich in complex compounds such as NOS,and undergo secondary cracking to form light components in the later stage;the hydrocarbon generation model of insoluble organic matter conforms to the traditional“Tissot”model,with an oil generation peak corresponding to Ro of 1.0%.
基金Project supported by Special Funds for Scientific and Technological Innovation Projects in Tianjin,China(Grant No.10FDZDGX00400)the Tianjin Research Program of Application Foundation and Advanced Technology,China(Grant No.15JCQNJC01100)
文摘We investigate the intensity and efficiency of a compressed echo, which is important in arbitrary waveform generation（AWG）. A new model of compressed echo is proposed based on the optical Bloch equations, which exposes much more detailed parameters than the conventional model, such as the time delay of the chirp lasers, the nature of the rare-earth-iondoped crystal, etc. According to the novel model of compressed echo, we find that reducing the time delay of the chirp lasers and scanning the lasers around the center frequency of the inhomogeneously broadened spectrum, while utilizing a crystal with larger coherence time and excitation lifetime can improve the compressed echo＇s intensity and efficiency. The theoretical analysis is validated by numerical simulations.
基金Agency for Science,Technology and Research(M22K2c0089)。
文摘We report the first demonstration of high-efficiency ultraviolet(UV)pulse generation in a resonance-free anti-resonant hollow-core fiber(AR-HCF).Using the wet-etching technique,we successfully reduced the cladding-tube wall thickness of the AR-HCF to 115 nm,thereby eliminating all cladding-induced structural resonances between the near-infrared pump and the deep UV wavelengths.This structural modification fundamentally suppresses competing conversion to other phase-matching points induced by structural resonances and mitigates the pump spectral broadening limitation,achieving a UV conversion efficiency as high as 12%—twice that of previous demonstrations in gas-filled AR-HCFs.This UV conversion efficiency is comparable to that of meter-scale gas-filled capillaries that require pump pulse energy of hundreds of microjoules while also maintaining the AR-HCF's inherent advantages of centimeter-scale compactness and low pump energy at the few microjoule level.
基金supported by the National Natural Science Foundation of China(Grant Nos.52071348 and 51979129)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20201006)the Natural Science Research of Jiangsu Higher Education Institutions of China(Grant No.22KJA130001).
文摘A numerical simulation method based on CFD has been established to simulate the fully coupled motion for an atten-uator-type wave energy converter(WEC).Based on this method,a detailed parametric analysis has been conducted to investigate the design of the rafts.The effects of different parameters(wave parameters,structural parameters and PTO parameters)on the hydrodynamic characteristics of the attenuator-type WEC were studied in detail.The results show that in terms of wave parameters,there is an optimal wave period,which makes the relative pitching angle amplitude of the WEC reach the maximum,and the increase of wave height is conducive to the relative pitching angle amplitude of wave energy.Under different wave conditions,the relative pitch angle of the parallelogram raft device is the maximum.In terms of structural parameters,the parallelogram attenuator-type device has the optimal values in different relative directions,different distances and different apex angle,which makes the relative motion amplitude of the device reach the maximum,and the spacing and the apex angle have influence on the motion frequency of the device,while the relative direction has almost no influence on it.In terms of PTO parameters,there is an optimal damping coefficient,which makes the power generation efficiency of the WEC reach the maximum.The research results provide a valuable reference for future research and design of the attenuator-type WEC.
基金National Natural Science Foundation of China(21575137)。
文摘Energy-efficient electrolytic hydrogen generation is highly desired but still remains challenging.In this work,we demonstrate that a Cu_(3)P nanoarray on copper foam(Cu_(3)P/CF)behaves as a high-performance electrocatalyst for hydrazine oxidation reaction(HzOR)in alkaline electrolytes.A full electrolytic system employing Cu_(3)P/CF as both an anode for HzOR and a cathode for hydrogen evolution reaction drives 100 mA cm^(-2)at a voltage of 0.72 V in 1.0 M KOH aqueous solution with 0.5 M hydrazine.It also demonstrates high long-term stability.
基金supported by Chongqing Natural Science Foundation(cstc2019jcyj⁃msxm2000),Chongqing University of Science and Technology Graduate Science and Technology Innovation Project(JXXY201901)。
文摘For offshore hydraulic drive wind turbines,the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted.A low-speed high-torque radial piston pump is designed to replace the traditional fixed pump with a particular focus on its low-speed performance.The pump is characterized by small internal leakage at low wind speeds and high volumetric efficiency,which is beneficial to improve the power generation efficiency of the system.A new linear control method based on the PID algorithm and feedforward compensation was proposed to obtain the constant speed output control of variable motor at low wind speed.With the model for wind turbine and fixed pump-variable motor main drive system,the system was simulated and experimentally proved to verify the feasibility and anti-interference performance of the system control method at low wind speeds.A promising outcome was obtained on the response characteristics of system power and efficiency at low wind speeds.This can be a powerful technical support for the normal ustility of hydraulic drive wind turbines.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1400601,and 2022YFA1404501)the National Natural Science Fund for Distinguished Young Scholar(Grant No.11925403)the National Natural Science Foundation of China(Grant Nos.12122406,12192253,12274239,12274237,and U22A20258)。
文摘Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial structures.However,the nonlinear conversion efficiency is generally limited by the angular dispersion of optical resonances especially in nonparaxial photonics.Here,we propose a metagrating realizing a quasi-bound-state in the continuum in a flat band to dramatically improve the third harmonic generation(THG)efficiency.A superior operating angular range is achieved based on the interlayer and intralayer couplings,which are introduced by breaking the mirror symmetry of the metagrating.We demonstrate the relation of angular dispersion between the nonlinear and linear responses at different incident angles.We also elucidate the mechanism of these offaxis flat-band-based nonlinear conversions through different mode decomposition.Our scheme provides a robust and analytical way for nonparaxial nonlinear generation and paves the way for further applications such as wide-angle nonlinear information transmission and enhanced nonlinear generation under tight focusing.
基金supported by the National Natural Science Foundation of China(no.51432006)the Ministry of Education of China for the Changjiang Innovation Research Team(no.IRT13R24)+1 种基金the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project(no.B13025)the Innovation Program of Shanghai Municipal Education Commission.M.G.H.and C.Z.thank the Australian Research Council for support(DP170100411).
文摘Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suffciently high second-harmonic generation(SHG)effciencies coupled to wide transparency ranges and high laser damage thresholds.A series of new hydrous rare-earth iodates RE(IO_(3))_(3)·(H_(2)O)(RE=Y 1,Eu 2)and La_(2)(IO_(3))_(6)(H_(2)O)(3)have been synthesized through facile hydrothermal methods.1 and 2 are isostructural,crystallizing in the polar space group P21,while 3 crystallizes in the polar space group Pc.1-3 feature three-dimensional(3D)frameworks composed of alternately connected corner-shared dis torted[REO_(x)]polyhedra(RE=Y,Eu,and La;x=8,9)and[IO_(3)]^(−)groups.Optical studies showed that 1–3 exhibit good NLO properties,including strong SHG intensities(3.0×(1),4.5×(2),and 1.5×KH_(2)PO_(4)(3)),large band gaps(4.12(1),4.36(2),and 4.24 eV(3),with 2 possessing the largest band gap among the known SHG-active rare-earth-based iodates,high laser damage thresholds(LDT)(53×(1),43×(2),and 44×AgGaS_(2)(3)),and wide transparency ranges(ca.3.0–11.3μm)in the mid-IR region covering two criti cal IR transparency windows;1–3 are therefore potential candidate NLO materials.Density functional theory calculations on 1–3 confirm that their strong SHG responses and large band gaps are mainly derived from the synergistic effect of[IO_(3)]^(−)groups and rare-earth oxide polyhedra[REOx]in their 3D frameworks.We conclude that the introduction of rare-earth cations with moderate electropositivity into iodates may optimize the balance between SHG effciency and optical band gaps,the key requirement for high-performance NLO materials for practical applications.
基金supported by the National Natural Science Foundation of China(No.22205037 and 22373014)Natural Science Foundation of Fujian Province(2023J01498).
文摘In the quest for organic–inorganic metal halides(OIMHs)that harmoniously combine large second harmonic generation(SHG)efficiency with broad bandgaps,our study introduces a series of noncentrosymmetric and polar piperazine zinc halides,(C_(4)H_(11)N_(2))ZnX_(3)(X=Cl,Br,I).The distinct influence of halide anion size on the configuration of ZnNX_(3)tetrahedra is uncovered,revealing a design principle for enhancing SHG activity and manipulating bandgap characteristics.Specifically,(C_(4)H_(11)N_(2))ZnCl_(3)is the first example of deep-ultraviolet(deep-UV)nonlinear optical(NLO)OIMHs,with UV transparency lower than 190 nm and moderate SHG effect,0.8 times KH_(2)PO_(4)(KDP).Meanwhile,compared with(C_(4)H_(11)N_(2))ZnI_(3)(2.1 times KDP,4.52 eV),(C_(4)H_(11)N_(2))ZnBr_(3)boasts a widened bandgap of 5.53 eV while maintaining a striking SHG response(2.5 times KDP),representing a pinnacle in the SHG-bandgap balance among OIMHs with Eg exceeding 5.0 eV.Computational analyses underscore the critical roles of halide orbitals and ZnNX_(3)distortions in dictating SHG efficiency,with increasing halide polarizability correlating with heightened SHG contributions.This study paves the way for a novel approach to designing short-UV NLO crystals based on OIMHs.
基金supported by the National Natural Science Foundation of China(No.61401288)the Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2016)+1 种基金Integration of Cloud Computing and Big Data,Innovation of Science and Education(No.2017A15009)the Engineering Applications of Artificial Intelligence Technology Laboratory(No.PT201701)
文摘A computer generated holographic stereogram based on the wavefront recording plane （WRP） is presented. A WRP closed to the parallax image plane is introduced to record the complex amplitude in a small region for each point in the parallax image. By using three times of fast Fourier transform （FFT） to execute the Fresnel dif- fraction calculation between the WRP and the holographic stereogram plane, the object wave contributing to the hologram pattern can be achieved. The computation complexity of the proposed approach is dramatically reduced. The results show that the calculation time can be decreased by more than one order of magnitude.
基金supported by the National Basic Research Program of China(No.2013CBA01501)the National Natural Science Foundation of China(No.11520101003)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB16010200 and XDB07030300)the "Zhuoyue" Program of Beihang University(No.GZ216S1711)
文摘We systematically study the optimization of highly efficient terahertz（THz） generation in lithium niobate（LN）crystal pumped by 800 nm laser pulses with 30 fs pulse duration. At room temperature, we obtain a record optical-to-THz energy conversion efficiency of 0.43% by chirping the pump laser pulses. Our method provides a new technique for producing millijoule THz radiation in LN via optical rectification driven by joule-level Ti：sapphire laser systems, which deliver sub-50-fs pulse durations.
基金National Natural Science Foundation of China(NSFC)(61505236)Key Laboratory Foundation of Chinese Academy of Sciences(CAS)(CXJJ-15S099,CXJJ-17S026)Innovation Foundation of Shanghai Institute of Technical Physics(CX-54)
文摘We report the investigation on the performance of an amplification assisted difference frequency generation(AA-DFG) system driven by pulsed pump and continuous-wave primary signal lasers. A monolithic tandem lithium niobate superlattice was employed as the nonlinear crystal with a uniform grating section for the DFG process, followed by a chirp section for the optical parametric amplification process. The impacts of pump pulse shape, primary signal power, input beam diameter, and crystal structure on the pump-to-idler conversion efficiency of the AA-DFG system were comprehensively studied by numerically solving the coupled wave equations. It is concluded that square pump pulse and high primary signal power are beneficial to high pump-to-idler conversion efficiency. In addition, tighter input beam focus and smaller DFG length proportion could redeem the reduction in conversion efficiency resulting from wider acceptance bandwidths for the input lasers. We believe that such systems combining the merits of high stability inherited from cavity-free configuration and high efficiency attributed from the cascaded nonlinear conversion should be of great interest to a wide community,especially when the pulse shaping technique is incorporated.
文摘A new structure for efficient and cost-effective L-band amplified spontaneous emission (ASE) generation was experimentally investigated and demonstrated using a C/L-band coupler, an optical mirror, and a fiber Bragg grating (FBG). The proposed structure has about 1.5 dB increase of the power around 1570 nm compared with conventional one. Various structures for power enhancement were also considered.
基金supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China(Nos.11774286,11374238,11574247,11374008,and 11534008)
文摘We demonstrate the generation of non-classical photon pairs in a warm S-Rb atomic vapor （＇ell with no buffer gas or polarization preserving coatings via spontaneous four-wave mixing. We obtain the photon pairs with a 1/e correlation time of 40 ns and the violation of Cauchy-Sehwartz inequality by a factor of 23 - 3. This provides a convenient and efficient method to generate photon pair sources based on an atomic ensemble.
