Lightweight porous materials with high load-bearing,damage tolerance and energy absorption(EA)as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications,e.g....Lightweight porous materials with high load-bearing,damage tolerance and energy absorption(EA)as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications,e.g.aerospace,automobiles,electronics,etc.Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient,enabling stress homogenization,significant load bearing,and damage tolerance to protect the organism from high external pressures in the deep sea.This work illustrated that the complex hybrid wave shape in cuttlebone walls,becoming more tortuous from bottom to top,creates a lightweight,load-bearing structure with progressive failure.By mimicking the cuttlebone,a novel bionic hybrid structure(BHS)was proposed,and as a comparison,a regular corrugated structure and a straight wall structure were designed.Three types of designed structures have been successfully manufactured by laser powder bed fusion(LPBF)with NiTi powder.The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4μm.Microstructural analysis indicated that the LPBF-processed BHS had a strong(001)crystallographic orientation and an average size of 9.85μm.Mechanical analysis revealed the LPBF-processed BHS could withstand over 25000 times its weight without significant deformation and had the highest specific EA value(5.32 J·g^(−1))due to the absence of stress concentration and progressive wall failure during compression.Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity.Importantly,the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated(over 99% recovery rate).These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.展开更多
The distal end of the spinal cord and neuromuscular junction may develop secondary degeneration and damage following spinal cord injury because of the loss of neural connections. In this study, a rat model of spinal c...The distal end of the spinal cord and neuromuscular junction may develop secondary degeneration and damage following spinal cord injury because of the loss of neural connections. In this study, a rat model of spinal cord injury, established using a modified Allen＇s method, was injected with basic fibroblast growth factor solution via subarachnoid catheter. After injection, rats with spinal cord injury displayed higher scores on the Basso, Beattie and Bresnahan locomotor scale. Motor function was also well recovered and hematoxylin-eosin staining showed that spinal glial scar hyperplasia was not apparent. Additionally, anterior tibial muscle fibers slowly, but progressively, atrophied. Immu- nohistochemical staining showed that the absorbance values of calcitonin gene related peptide and acetylcholinesterase in anterior tibial muscle and spinal cord were similar, and injection of basic fi- broblast growth factor increased this absorbance. Results showed that after spinal cord injury, the distal motor neurons and motor endplate degenerated. Changes in calcitonin gene related peptide and acetylcholinesterase in the spinal cord anterior horn motor neurons and motor endplate then occurred that were consistent with this regeneration. Our findings indicate that basic fibroblast growth factor can protect the endplate through gene related peptide and acetylcholinesterase cord. attenuating the decreased expression of calcitonin n anterior horn motor neurons of the injured spinal展开更多
Mg-5Li-1Al-0.5Y alloy was rolled with different directions.The microstructure,mechanical properties and texture of the specimens were investigated with optical microscope,tensile tester and X-ray diffraction.The resul...Mg-5Li-1Al-0.5Y alloy was rolled with different directions.The microstructure,mechanical properties and texture of the specimens were investigated with optical microscope,tensile tester and X-ray diffraction.The results show that changing rolling directions can refine the grain size of as-rolled alloys.Meanwhile,rolling directions have an obvious influence on the mechanical properties and texture of Mg-5Li-1Al-0.5Y alloy,thus affecting the anisotropy of the alloy.The sheet,of which the RD(rolling direction)and ND(normal direction)are both changed between two passes,possesses the smallest anisotropy.From the texture results,changing rolling directions reduces the maximum pole density,making the highest point distribution region excursion and the highest point distributes more scatteredly.展开更多
Label-sensor is an essential component of the label printer which is becoming a most significant tool for the development of Internet of Things(IoT).However,some drawbacks of the traditional infrared label-sensor make...Label-sensor is an essential component of the label printer which is becoming a most significant tool for the development of Internet of Things(IoT).However,some drawbacks of the traditional infrared label-sensor make the printer fail to realize the high-speed recognition of labels as well as stable printing.Herein,we propose a selfpowered and highly sensitive tribo-label-sensor(TLS)for accurate label identification,positioning and counting by embedding triboelectric nanogenerator into the indispensable roller structure of a label printer.The sensing mechanism,device parameters and deep comparison with infrared sensor are systematically studied both in theory and experiment.As the results,TLS delivers 6 times higher signal magnitude than traditional one.Moreover,TLS is immune to label jitter and temperature variation during fast printing and can also be used for transparent label directly and shows long-term robustness.This work may provide an alternative toolkit with outstanding advantages to improve current label printer and further promote the development of IoT.展开更多
This paper expounded the current situation and genetic mechanisms of short-vine watermelon breeding from the aspects of material sources,breeding process and genetic characteristics of F_1,hoping to provide a theoreti...This paper expounded the current situation and genetic mechanisms of short-vine watermelon breeding from the aspects of material sources,breeding process and genetic characteristics of F_1,hoping to provide a theoretical basis for short-vine watermelon breeding,and breeding materials for watermelon planting innovation,as well as new opportunities for high-quality and high-yield watermelon.展开更多
Accurate identification of the correct,biologically relevant RNA structures is critical to understanding various aspects of RNA biology since proper folding represents the key to the functionality of all types of RNA ...Accurate identification of the correct,biologically relevant RNA structures is critical to understanding various aspects of RNA biology since proper folding represents the key to the functionality of all types of RNA molecules and plays pivotal roles in many essential biological processes.Thus,a plethora of approaches have been developed to predict,identify,or solve RNA structures based on various computational,molecular,genetic,chemical,or physicochemical strategies.Purely computational approaches hold distinct advantages over all other strategies in terms of the ease of implementation,time,speed,cost,and throughput,but they strongly underperform in terms of accuracy that significantly limits their broader application.Nonetheless,the advantages of these methods led to a steady development of multiple in silico RNA secondary structure prediction approaches including recent deep learning-based programs.Here,we compared the accuracy of predictions of biologically relevant secondary structures of dozens of self-cleaving ribozyme sequences using seven in silico RNA folding prediction tools with tasks of varying complexity.We found that while many programs performed well in relatively simple tasks,their performance varied significantly in more complex RNA folding problems.However,in general,a modern deep learning method outperformed the other programs in the complex tasks in predicting the RNA secondary structures,at least based on the specific class of sequences tested,suggesting that it may represent the future of RNA structure prediction algorithms.展开更多
Cylindrical vector beams(CVBs)with special polarization distribution have been extensively investigated due to the unique ways of interacting with matter.Although several configurations have been developed to generate...Cylindrical vector beams(CVBs)with special polarization distribution have been extensively investigated due to the unique ways of interacting with matter.Although several configurations have been developed to generate CVBs,such as Q-plates and subwavelength gratings,the bandwidth of a single CVB is inherently narrow due to the phase geometry,which would limit its application for femtosecond lasers.Here,a broadband CVB mode converter based on an acoustically induced fiber grating(AIFG)and a tuning method of dispersion turning point(DTP)is demonstrated both theoretically and experimentally with the 3-dB bandwidth of 125 nm,which is more than 10 times that of conventional AIFGs.Not only can the DTP wavelength be tuned from the original 1500 nm to 1650 nm by thinning the fiber,but also the stable generation of a single broadband HE_(21)^(odd/even) mode can be controllably implemented by adjusting the polarization state of the incident light,owing to the larger beat length difference between HE21 and other CV modes.Additionally,the femtosecond CVBs and orbital angular momentum(OAM)modes are successfully generated and amplified by combining the broadband AIFG with a figure-9 mode-locked fiber laser.Meanwhile,it is verified by simulation that the choice of broadband CV mode and the tunability of DTP wavelength can be realized by designing ring-core fibers with different structures,which can furthermore improve the flexibility of generating high purity CVBs.This study provides a highly controllable technique for the generation of broadband CVBs and OAMs paving the way for high-capacity CVBs communication.展开更多
An optical phase locking method based on direct phase control is proposed.The core of this method is to synchronize the carrier by directly changing the phase of the local beam.The corresponding experimental device an...An optical phase locking method based on direct phase control is proposed.The core of this method is to synchronize the carrier by directly changing the phase of the local beam.The corresponding experimental device and the supporting algorithm were configured to verify the feasibility of this method.Phase locking can be completed without cycle skipping,and the acquisition time is 530 ns.Without an optical preamplifier,a sensitivity of-34.4 d Bm is obtained,and the bit error rate is 10^(-9) for 2.5 Gbit/s binary phase-shift keying modulation.The measured standard deviation of the phase error is 5.2805°.展开更多
We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Consider...We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Considering the non-negligible loop delay, we optimize the loop natural frequency. Without error correction coding, a sensitivity of -37 dBm/-35 dBm is achieved, while the bit error rate is below 10-9 at 2.5 Gbaud/5 Gbaud rate.For the QPSK communication system, the bit rate is twice the baud rate. The loop natural frequency is 0.647 Mrad/s, and the minimized steady-state phase-error standard deviation is 3.83°.展开更多
Aiming at coherence degradation during target detection,a suppressing method based on frequency-modulated continuous wave coherent lidar is proposed.Combined with a random iteration algorithm,a long-pulse echo signal ...Aiming at coherence degradation during target detection,a suppressing method based on frequency-modulated continuous wave coherent lidar is proposed.Combined with a random iteration algorithm,a long-pulse echo signal with coherent degradation is matched with random phase noise of a certain frequency and achieves coherence restoration.Simulation and field experiment results show that this proposed method can recover the intrapulse coherence in long-pulse echo signals.In addition,for the real target echo signal at 4.2 and 19.8 km,the peak signal-to-noise ratio processed by this method is increased by 0.35 times and 4 times after pulse compression,respectively.展开更多
A scanning three-dimensional coherent laser radar(ladar) based on the frequency modulated continuous wave(FMCW) is proposed and demonstrated, which can obtain many three-dimensional high-quality images. The system uti...A scanning three-dimensional coherent laser radar(ladar) based on the frequency modulated continuous wave(FMCW) is proposed and demonstrated, which can obtain many three-dimensional high-quality images. The system utilizes an electro-optic modulator and an optical filter to output a linear FMCW with a bandwidth of 2 GHz. The flexible and variable rotating double prism is used for beam scanning. The images of flight demonstration are formed by attitude compensation correction. The experiment result validates the performance of our system for airborne three-dimensional scanning imaging.展开更多
Efficiently converting the random vibration energy widely existed in human activities and natural environments into electricity is significant to the local power supply of sensor nodes in the internet of things.Howeve...Efficiently converting the random vibration energy widely existed in human activities and natural environments into electricity is significant to the local power supply of sensor nodes in the internet of things.However,the conversion efficiency of energy harvester is relatively low due to the limitation of device’s intrinsic frequency.In this work,a multi-layered,wavy super-structuredtriboelectric nanogenerator(SS-TENG)is designed,whose output performances can be greatly promoted by combining the charge excitation mechanism.The steel sheet acts not only as an electrode but also as a supporter for the overall frame of SSTENG,which effectively improves the space utilization rate and results in a volume charge density up to 129 mC·m^(−3).In addition,the resonant frequency width of the SS-TENG can be widened by changing the parameters of the superstructure.For demonstration,the SS-TENG can sustainably drive two temperature and humidity sensors in parallel by harvesting vibration energy.This work may provide an effective strategy for harvesting vibration energy and broadening frequency response.展开更多
To develop self-recovery intelligent components based on resistance heating and obtain satisfactory performance in practical applications,this study optimized the forming quality,dimensional accuracy,and phase transfo...To develop self-recovery intelligent components based on resistance heating and obtain satisfactory performance in practical applications,this study optimized the forming quality,dimensional accuracy,and phase transformation temperatures of Nickel-titanium(NiTi)alloys by controlling the process parameters.The tensile properties and shape-memory effects of the NiTi alloys prepared using the optimized process were clarified.The relationship between the change in temperature and the shape recovery process of the deformed structure under electrical excitation was investigated.The results show that the suitable processing window for ensuring the forming quality without noticeable distortion and macro cracks depends on the laser parameters.In both the X and Y directions,the measured dimensions increased with an increase in laser power and first decreased and then stabilized with an increase in scanning speed.The XRD results showed that all the as-built samples consisted of B2 austenite and B19’martensite phases and Ni3Ti.Mechanical tests suggested that excellent tensile properties with a tensile strength of 753.28 MPa and elongation of 6.81%could be obtained under the optimal parameters of 250 W and 1200 mm/s.An excellent shape-recovery rate of 88.23%was achieved under the optimal parameters.Subsequently,chiral lattice structures were successfully fabricated by laser powder bed fusion(LPBF)under the optimal parameters,and a shape-recovery rate of 96.7%was achieved under electrical actuation for a structure with a pre-compressed strain of 20%.This study also found that the temperatures at the grasp regions were always higher than those at other positions because of the generation of contact resistance at the grasp regions.This facilitates the rapid recovery of the structure at the grasp regions,which has important implications for the design iteration of NiTi smart components.展开更多
The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying...The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying the requirements,the nutation radius is less than 1.13μm,the accuracy of the nutation trail is less than 0.04μm,and the detection range is[?5μm,+5μm].The nutation frequency is 160 times spot position jitter frequency and 100 times intensity jitter frequency of incident light.The analysis is of great significance for determining nutation radius and frequency in the tracking system based on fiber nutation.展开更多
The black spot disease caused by Alternaria alternata on Yali pears is a great concern as it compromises their edible quality and commercial value.To realize rapid and non-destructive classification of this disease,hy...The black spot disease caused by Alternaria alternata on Yali pears is a great concern as it compromises their edible quality and commercial value.To realize rapid and non-destructive classification of this disease,hyperspectral imaging(HSI)technology was combined with two-dimensional correlation spectroscopy(2DCOS)analysis.A total of 150 pear samples at different decay grades were prepared.After obtaining the HSI images,the whole sample was demarcated as the region of interest,and the spectral information was extracted.Seven preprocessing methods were applied and compared to build the classification models.Thereafter,using the inoculation day as an external perturbation,2DCOS was used to select the feature-related wavebands for black spot disease identification,and the result was compared to those obtained using competitive adaptive reweighting sampling and the successive projections algorithm.Results demonstrated that the simplified least squares support vector model based on 2DCOS-identified feature wavebands yielded the best performance with the identification accuracy,precision,sensitivity,and specificity of 97.30%,94.60%,96.16%,and 98.21%,respectively.Therefore,2DCOS can effectively interpret the feature-related wavebands,and its combination with HSI is an effective tool to predict black spot disease on Yali pears.展开更多
To investigate the fog chemistry along the Yangtze River basin, a field observation experiment was performed from Shanghai to Vv＇uhan during November 2015. Fifteen fog water samples were collected by using a three-st...To investigate the fog chemistry along the Yangtze River basin, a field observation experiment was performed from Shanghai to Vv＇uhan during November 2015. Fifteen fog water samples were collected by using a three-stage Caltech Active Strand Cloud water Collector （CASCC）. The three-stage CASCC was mounted on the board of a ship. PH, electrical conductivity （EC）, H202, HCHO, S（ll0, ten inorganic ions, seven organicacids and sixteen trace metal elements were measured in this study. The pH of fog water samples ranged from weakly acidic （pH 4.3） to weakly alkaline （pH 7.05） and the EC ranged from 32.4 to 436.3 μS/cm. The main cations in fog water were NH^4＋ and Ca2＋, accounting for 12.35% and 29.07% of those inorganic ions, respectively. In addition, SO24- and NO^-3 contributed to 25.52% and 12.93% to total anion concentrations respectively. Moreover, the dominant kinds of organicacids were formate and oxalate, occupying 45.28% and 28.03% of the total organicacids, respectively. For trace metal elements in fog samples, Al, Fe, Zn, and Ba revealed 34.6%, 16.4%, 19.3%, and 20.9% contributions to these sixteen trace element concentrations, respectively. The results indicated that pollutants were mainly from human activities, including fossil fuel combustion, biomass burning, steel-making, stone quarrying and sand digging. Besides, natural sources including natural background levels and long-range transport of sea salt particles also aggravated the pollution levels in the fog events along the Yangtze River.展开更多
This Letter gives the general construction of an enhanced self-heterodyne synthetic aperture imaging ladar（SAIL） system, and proposes the principle of image processing. A point target is reconstructed in the enhance...This Letter gives the general construction of an enhanced self-heterodyne synthetic aperture imaging ladar（SAIL） system, and proposes the principle of image processing. A point target is reconstructed in the enhanced self-heterodyne SAIL as well as in down-looking SAIL experiments, and the achieved imaging resolution of the enhanced self-heterodyne SAIL is analyzed. The signal-to-noise ratio（SNR） of the point target final image in the enhanced self-heterodyne SAIL is higher than that in the down-looking SAIL. The enhanced self-heterodyne SAIL can improve the SNR of the target image in far-distance imaging, with practicality.展开更多
Soft starters are effective devices used to provide overload protection for motors from large mechanical shocks during the start-up period.However,existing soft starters require additional power supplies,sensors,and c...Soft starters are effective devices used to provide overload protection for motors from large mechanical shocks during the start-up period.However,existing soft starters require additional power supplies,sensors,and complex control elements that pose serious challenges to the integration,versatility,and operability of mechanical transmission system.Herein,we propose a newly soft starter based on the triboelectric nanogenerator(TENG)and electrorheological fluid(ERF)to realize a self-powered mechanical transmission system.Both ERF’s rheological characteristic and the baffle structure play a role in the torque of device.Driven by TENG,the soft starter with optimized baffle achieves a 715%growth in transmission torque compared to that of the device without baffle.And a smooth start is obtained with transmission speeds ranging from 0%to 100%.In application demonstration,this triboelectric soft starter(TSS)has the capacity to gain a smooth operation of the high-speed motor.In contrast,the direct start generates an overshoot,leading to a break in the conveyor belt.The TSS designed in this work with the advantages of self-powered,highly integrated,easy to operate,and low cost,provides a prospective strategy for broadening the application of TENG in mechanical transmission systems.展开更多
On August 4,2024,the first set of magnetobiased superconducting current limiters(MBSFCL)completed a 6-month grid-connected demonstration operation at the 66 kV Zhangtaizi substation in Liaoyang City,China.Moreover,it ...On August 4,2024,the first set of magnetobiased superconducting current limiters(MBSFCL)completed a 6-month grid-connected demonstration operation at the 66 kV Zhangtaizi substation in Liaoyang City,China.Moreover,it successfully limited the current dur-ing an actual three-phase short-circuit fault in a transmission line,thereby fully verifying the fault-current-limiting characteristics of the MBSFCL.This practical breakthrough signifies a noteworthy milestone in China’s power system,providing an innovative superconducting fault current-limiting solution for international urban power grids security[1].展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52225503)National Key Research and Development Program of China(Grant No.2022YFB3805701)+1 种基金Development Program of Jiangsu Province(Grant Nos.BE2022069 and BE2022069-1)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX21-0207).
文摘Lightweight porous materials with high load-bearing,damage tolerance and energy absorption(EA)as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications,e.g.aerospace,automobiles,electronics,etc.Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient,enabling stress homogenization,significant load bearing,and damage tolerance to protect the organism from high external pressures in the deep sea.This work illustrated that the complex hybrid wave shape in cuttlebone walls,becoming more tortuous from bottom to top,creates a lightweight,load-bearing structure with progressive failure.By mimicking the cuttlebone,a novel bionic hybrid structure(BHS)was proposed,and as a comparison,a regular corrugated structure and a straight wall structure were designed.Three types of designed structures have been successfully manufactured by laser powder bed fusion(LPBF)with NiTi powder.The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4μm.Microstructural analysis indicated that the LPBF-processed BHS had a strong(001)crystallographic orientation and an average size of 9.85μm.Mechanical analysis revealed the LPBF-processed BHS could withstand over 25000 times its weight without significant deformation and had the highest specific EA value(5.32 J·g^(−1))due to the absence of stress concentration and progressive wall failure during compression.Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity.Importantly,the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated(over 99% recovery rate).These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.
基金supported by a grant from the Hunan Provincial Science and Technology Ministry in China, No. 2012SK3222Funding for New Teachers by the Ministry of Education in China, No. 200805331166
文摘The distal end of the spinal cord and neuromuscular junction may develop secondary degeneration and damage following spinal cord injury because of the loss of neural connections. In this study, a rat model of spinal cord injury, established using a modified Allen＇s method, was injected with basic fibroblast growth factor solution via subarachnoid catheter. After injection, rats with spinal cord injury displayed higher scores on the Basso, Beattie and Bresnahan locomotor scale. Motor function was also well recovered and hematoxylin-eosin staining showed that spinal glial scar hyperplasia was not apparent. Additionally, anterior tibial muscle fibers slowly, but progressively, atrophied. Immu- nohistochemical staining showed that the absorbance values of calcitonin gene related peptide and acetylcholinesterase in anterior tibial muscle and spinal cord were similar, and injection of basic fi- broblast growth factor increased this absorbance. Results showed that after spinal cord injury, the distal motor neurons and motor endplate degenerated. Changes in calcitonin gene related peptide and acetylcholinesterase in the spinal cord anterior horn motor neurons and motor endplate then occurred that were consistent with this regeneration. Our findings indicate that basic fibroblast growth factor can protect the endplate through gene related peptide and acetylcholinesterase cord. attenuating the decreased expression of calcitonin n anterior horn motor neurons of the injured spinal
基金This work was supported by the Heilongjiang Province Youth Skeleton Program(1252G018)Research Fund for the Doctoral Program of Higher Education(20132304110006)+3 种基金Project of Science and Technology of Heilongjiang Province Education Department(12511068)Fundamental Research Funds for the Central Universities(HEUCF20151006)Heilongjiang Province Natural Science Foundation(E201420)Harbin City Application Technology Research and Devolopment Project(2015AE005).
文摘Mg-5Li-1Al-0.5Y alloy was rolled with different directions.The microstructure,mechanical properties and texture of the specimens were investigated with optical microscope,tensile tester and X-ray diffraction.The results show that changing rolling directions can refine the grain size of as-rolled alloys.Meanwhile,rolling directions have an obvious influence on the mechanical properties and texture of Mg-5Li-1Al-0.5Y alloy,thus affecting the anisotropy of the alloy.The sheet,of which the RD(rolling direction)and ND(normal direction)are both changed between two passes,possesses the smallest anisotropy.From the texture results,changing rolling directions reduces the maximum pole density,making the highest point distribution region excursion and the highest point distributes more scatteredly.
基金supported by the National Key Research and Development Program(2021YFA1201602)the NSFC(62004017)+2 种基金the Fundamental Research Funds for the Central Universities(2021CDJQY-019)J.C.also want to acknowledge the supporting from the Natural Science Foundation of Chongqing(Grant No.cstc2021jcyjmsxmX0746)the Scientific Research Project of Chongqing Education Committee(Grant No.KJQN202100522).
文摘Label-sensor is an essential component of the label printer which is becoming a most significant tool for the development of Internet of Things(IoT).However,some drawbacks of the traditional infrared label-sensor make the printer fail to realize the high-speed recognition of labels as well as stable printing.Herein,we propose a selfpowered and highly sensitive tribo-label-sensor(TLS)for accurate label identification,positioning and counting by embedding triboelectric nanogenerator into the indispensable roller structure of a label printer.The sensing mechanism,device parameters and deep comparison with infrared sensor are systematically studied both in theory and experiment.As the results,TLS delivers 6 times higher signal magnitude than traditional one.Moreover,TLS is immune to label jitter and temperature variation during fast printing and can also be used for transparent label directly and shows long-term robustness.This work may provide an alternative toolkit with outstanding advantages to improve current label printer and further promote the development of IoT.
文摘This paper expounded the current situation and genetic mechanisms of short-vine watermelon breeding from the aspects of material sources,breeding process and genetic characteristics of F_1,hoping to provide a theoretical basis for short-vine watermelon breeding,and breeding materials for watermelon planting innovation,as well as new opportunities for high-quality and high-yield watermelon.
基金supported by the National Natural Science Foundation of China(Grant No.32000462 to Fei Qi,Grant No.32170619 to Philipp Kapranovand Grant No.32201055 to Yue Chen)+2 种基金the Research Fund for International Senior Scientists from the National Natural Science Foundation of China(Grant No.32150710525 to Philipp Kapranov)the Natural Science Foundation of Fujian Province,China(Grant No.2020J02006 to Philipp Kapranov)the Scientific Research Funds of Huaqiao University,China(Grant No.22BS114 to Fei Qi,Grant No.21BS127 to Yue Chen,and Grant No.15BS101 to Philipp Kapranov).
文摘Accurate identification of the correct,biologically relevant RNA structures is critical to understanding various aspects of RNA biology since proper folding represents the key to the functionality of all types of RNA molecules and plays pivotal roles in many essential biological processes.Thus,a plethora of approaches have been developed to predict,identify,or solve RNA structures based on various computational,molecular,genetic,chemical,or physicochemical strategies.Purely computational approaches hold distinct advantages over all other strategies in terms of the ease of implementation,time,speed,cost,and throughput,but they strongly underperform in terms of accuracy that significantly limits their broader application.Nonetheless,the advantages of these methods led to a steady development of multiple in silico RNA secondary structure prediction approaches including recent deep learning-based programs.Here,we compared the accuracy of predictions of biologically relevant secondary structures of dozens of self-cleaving ribozyme sequences using seven in silico RNA folding prediction tools with tasks of varying complexity.We found that while many programs performed well in relatively simple tasks,their performance varied significantly in more complex RNA folding problems.However,in general,a modern deep learning method outperformed the other programs in the complex tasks in predicting the RNA secondary structures,at least based on the specific class of sequences tested,suggesting that it may represent the future of RNA structure prediction algorithms.
基金National Natural Science Foundation of China(12274281,62275148,U2241237)Open Research Fund of State Key Laboratory of Advanced Optical Communication Systems and Networks,Shanghai Jiao Tong University(2023GZKF021)+1 种基金Jiangsu Province’s Industry Outlook and Key Core Technologies-Key Projects(BE2022055-4)111 Project(D20031).
文摘Cylindrical vector beams(CVBs)with special polarization distribution have been extensively investigated due to the unique ways of interacting with matter.Although several configurations have been developed to generate CVBs,such as Q-plates and subwavelength gratings,the bandwidth of a single CVB is inherently narrow due to the phase geometry,which would limit its application for femtosecond lasers.Here,a broadband CVB mode converter based on an acoustically induced fiber grating(AIFG)and a tuning method of dispersion turning point(DTP)is demonstrated both theoretically and experimentally with the 3-dB bandwidth of 125 nm,which is more than 10 times that of conventional AIFGs.Not only can the DTP wavelength be tuned from the original 1500 nm to 1650 nm by thinning the fiber,but also the stable generation of a single broadband HE_(21)^(odd/even) mode can be controllably implemented by adjusting the polarization state of the incident light,owing to the larger beat length difference between HE21 and other CV modes.Additionally,the femtosecond CVBs and orbital angular momentum(OAM)modes are successfully generated and amplified by combining the broadband AIFG with a figure-9 mode-locked fiber laser.Meanwhile,it is verified by simulation that the choice of broadband CV mode and the tunability of DTP wavelength can be realized by designing ring-core fibers with different structures,which can furthermore improve the flexibility of generating high purity CVBs.This study provides a highly controllable technique for the generation of broadband CVBs and OAMs paving the way for high-capacity CVBs communication.
基金supported by the National Key R&D Program of China(No.2020YFB0408302)Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB43030400)+1 种基金National Natural Science Foundation of China(No.91938302)Key Project of Chinese Academy of Sciences(No.ZDRWKT-2019-1-01-0302)。
文摘An optical phase locking method based on direct phase control is proposed.The core of this method is to synchronize the carrier by directly changing the phase of the local beam.The corresponding experimental device and the supporting algorithm were configured to verify the feasibility of this method.Phase locking can be completed without cycle skipping,and the acquisition time is 530 ns.Without an optical preamplifier,a sensitivity of-34.4 d Bm is obtained,and the bit error rate is 10^(-9) for 2.5 Gbit/s binary phase-shift keying modulation.The measured standard deviation of the phase error is 5.2805°.
文摘We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying(QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Considering the non-negligible loop delay, we optimize the loop natural frequency. Without error correction coding, a sensitivity of -37 dBm/-35 dBm is achieved, while the bit error rate is below 10-9 at 2.5 Gbaud/5 Gbaud rate.For the QPSK communication system, the bit rate is twice the baud rate. The loop natural frequency is 0.647 Mrad/s, and the minimized steady-state phase-error standard deviation is 3.83°.
基金supported by the National Key Research and Development Program of China(No.2020YFB0408302)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB43030400)。
文摘Aiming at coherence degradation during target detection,a suppressing method based on frequency-modulated continuous wave coherent lidar is proposed.Combined with a random iteration algorithm,a long-pulse echo signal with coherent degradation is matched with random phase noise of a certain frequency and achieves coherence restoration.Simulation and field experiment results show that this proposed method can recover the intrapulse coherence in long-pulse echo signals.In addition,for the real target echo signal at 4.2 and 19.8 km,the peak signal-to-noise ratio processed by this method is increased by 0.35 times and 4 times after pulse compression,respectively.
基金This work was supported by the Key Project of Zhejiang Provincial Natural Science Foundation(Grant No.LZ22E050001)the National Natural Science Foundation of China(Grant No.82001918).
基金supported by the National Natural Science Foundation of China (No. 61605226)
文摘A scanning three-dimensional coherent laser radar(ladar) based on the frequency modulated continuous wave(FMCW) is proposed and demonstrated, which can obtain many three-dimensional high-quality images. The system utilizes an electro-optic modulator and an optical filter to output a linear FMCW with a bandwidth of 2 GHz. The flexible and variable rotating double prism is used for beam scanning. The images of flight demonstration are formed by attitude compensation correction. The experiment result validates the performance of our system for airborne three-dimensional scanning imaging.
基金the National Key Research and Development Program(No.2021YFA1201602)the NSFC(No.62004017)+3 种基金the Fundamental Research Funds for the Central Universities(No.2021CDJQY-019)the Graduate Research and Innovation Foundation of Chongqing,China(No.CYB22047)J.C.also wants to acknowledge the supports from the Natural Science Foundation of Chongqing(No.cstc2021jcyjmsxmX0746)the Scientific Research Project of Chongqing Education Committee(No.KJQN202100522).
文摘Efficiently converting the random vibration energy widely existed in human activities and natural environments into electricity is significant to the local power supply of sensor nodes in the internet of things.However,the conversion efficiency of energy harvester is relatively low due to the limitation of device’s intrinsic frequency.In this work,a multi-layered,wavy super-structuredtriboelectric nanogenerator(SS-TENG)is designed,whose output performances can be greatly promoted by combining the charge excitation mechanism.The steel sheet acts not only as an electrode but also as a supporter for the overall frame of SSTENG,which effectively improves the space utilization rate and results in a volume charge density up to 129 mC·m^(−3).In addition,the resonant frequency width of the SS-TENG can be widened by changing the parameters of the superstructure.For demonstration,the SS-TENG can sustainably drive two temperature and humidity sensors in parallel by harvesting vibration energy.This work may provide an effective strategy for harvesting vibration energy and broadening frequency response.
基金National Natural Science Foundation of China(Grant Nos.52225503,U1930207,and 51735005)Basic Strengthening Program of China(Grant No.2019-JCJQ-JJ-331)+1 种基金National Natural Science Foundation of China for Creative Research Groups of China(Grant No.51921003)Postgraduate Research&Practice Innovation Program of Jiangsu Provincial of China(Grant No.KYCX21-0207).
文摘To develop self-recovery intelligent components based on resistance heating and obtain satisfactory performance in practical applications,this study optimized the forming quality,dimensional accuracy,and phase transformation temperatures of Nickel-titanium(NiTi)alloys by controlling the process parameters.The tensile properties and shape-memory effects of the NiTi alloys prepared using the optimized process were clarified.The relationship between the change in temperature and the shape recovery process of the deformed structure under electrical excitation was investigated.The results show that the suitable processing window for ensuring the forming quality without noticeable distortion and macro cracks depends on the laser parameters.In both the X and Y directions,the measured dimensions increased with an increase in laser power and first decreased and then stabilized with an increase in scanning speed.The XRD results showed that all the as-built samples consisted of B2 austenite and B19’martensite phases and Ni3Ti.Mechanical tests suggested that excellent tensile properties with a tensile strength of 753.28 MPa and elongation of 6.81%could be obtained under the optimal parameters of 250 W and 1200 mm/s.An excellent shape-recovery rate of 88.23%was achieved under the optimal parameters.Subsequently,chiral lattice structures were successfully fabricated by laser powder bed fusion(LPBF)under the optimal parameters,and a shape-recovery rate of 96.7%was achieved under electrical actuation for a structure with a pre-compressed strain of 20%.This study also found that the temperatures at the grasp regions were always higher than those at other positions because of the generation of contact resistance at the grasp regions.This facilitates the rapid recovery of the structure at the grasp regions,which has important implications for the design iteration of NiTi smart components.
文摘The influences of nutation trail accuracy,simplification of coupling model,spot position jitter,and power variation of incident light on the detection error are analyzed theoretically.Under the condition of satisfying the requirements,the nutation radius is less than 1.13μm,the accuracy of the nutation trail is less than 0.04μm,and the detection range is[?5μm,+5μm].The nutation frequency is 160 times spot position jitter frequency and 100 times intensity jitter frequency of incident light.The analysis is of great significance for determining nutation radius and frequency in the tracking system based on fiber nutation.
基金financially supported by Hebei Province Key Research and Development Project(Grant No.20327111D)Basic Scientific Research Funds of Hebei Provincial Universities(Grant No.KY202002)+1 种基金Key Laboratory of Modern Agricultural Engineering,Tarim University(Grant No.TDNG2020102)the National Natural Science Foundation of China(Grant No.31960498).
文摘The black spot disease caused by Alternaria alternata on Yali pears is a great concern as it compromises their edible quality and commercial value.To realize rapid and non-destructive classification of this disease,hyperspectral imaging(HSI)technology was combined with two-dimensional correlation spectroscopy(2DCOS)analysis.A total of 150 pear samples at different decay grades were prepared.After obtaining the HSI images,the whole sample was demarcated as the region of interest,and the spectral information was extracted.Seven preprocessing methods were applied and compared to build the classification models.Thereafter,using the inoculation day as an external perturbation,2DCOS was used to select the feature-related wavebands for black spot disease identification,and the result was compared to those obtained using competitive adaptive reweighting sampling and the successive projections algorithm.Results demonstrated that the simplified least squares support vector model based on 2DCOS-identified feature wavebands yielded the best performance with the identification accuracy,precision,sensitivity,and specificity of 97.30%,94.60%,96.16%,and 98.21%,respectively.Therefore,2DCOS can effectively interpret the feature-related wavebands,and its combination with HSI is an effective tool to predict black spot disease on Yali pears.
基金supported by the National Natural Science Foundation of China (Nos. 41605113, 41375126)the Taishan Scholar Grand (No. ts20120552)
文摘To investigate the fog chemistry along the Yangtze River basin, a field observation experiment was performed from Shanghai to Vv＇uhan during November 2015. Fifteen fog water samples were collected by using a three-stage Caltech Active Strand Cloud water Collector （CASCC）. The three-stage CASCC was mounted on the board of a ship. PH, electrical conductivity （EC）, H202, HCHO, S（ll0, ten inorganic ions, seven organicacids and sixteen trace metal elements were measured in this study. The pH of fog water samples ranged from weakly acidic （pH 4.3） to weakly alkaline （pH 7.05） and the EC ranged from 32.4 to 436.3 μS/cm. The main cations in fog water were NH^4＋ and Ca2＋, accounting for 12.35% and 29.07% of those inorganic ions, respectively. In addition, SO24- and NO^-3 contributed to 25.52% and 12.93% to total anion concentrations respectively. Moreover, the dominant kinds of organicacids were formate and oxalate, occupying 45.28% and 28.03% of the total organicacids, respectively. For trace metal elements in fog samples, Al, Fe, Zn, and Ba revealed 34.6%, 16.4%, 19.3%, and 20.9% contributions to these sixteen trace element concentrations, respectively. The results indicated that pollutants were mainly from human activities, including fossil fuel combustion, biomass burning, steel-making, stone quarrying and sand digging. Besides, natural sources including natural background levels and long-range transport of sea salt particles also aggravated the pollution levels in the fog events along the Yangtze River.
基金supported by the National Natural Science Foundation of China(Nos.61605226 and 61505233)the Key Laboratory of Space Laser Communication and Detection Technology of Chinese Academy of Sciences
文摘This Letter gives the general construction of an enhanced self-heterodyne synthetic aperture imaging ladar（SAIL） system, and proposes the principle of image processing. A point target is reconstructed in the enhanced self-heterodyne SAIL as well as in down-looking SAIL experiments, and the achieved imaging resolution of the enhanced self-heterodyne SAIL is analyzed. The signal-to-noise ratio（SNR） of the point target final image in the enhanced self-heterodyne SAIL is higher than that in the down-looking SAIL. The enhanced self-heterodyne SAIL can improve the SNR of the target image in far-distance imaging, with practicality.
基金Guo,H.Y.want to acknowledge the support from the National Key Research and Development Program(No.2021YFA1201602)the Graduate Research and Innovation Foundation of Chongqing,China(No.CYB22047)+3 种基金the National Natural Science Foundation of China(NSFC)(Nos.62004017 and U21A20147)This research was also supported by the Scientific and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJQN202100522 and KJQN202200514)the Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0746)the Dr.“Through Train”Scientific Research Program(No.CSTB2022BSXM-JCX0091).
文摘Soft starters are effective devices used to provide overload protection for motors from large mechanical shocks during the start-up period.However,existing soft starters require additional power supplies,sensors,and complex control elements that pose serious challenges to the integration,versatility,and operability of mechanical transmission system.Herein,we propose a newly soft starter based on the triboelectric nanogenerator(TENG)and electrorheological fluid(ERF)to realize a self-powered mechanical transmission system.Both ERF’s rheological characteristic and the baffle structure play a role in the torque of device.Driven by TENG,the soft starter with optimized baffle achieves a 715%growth in transmission torque compared to that of the device without baffle.And a smooth start is obtained with transmission speeds ranging from 0%to 100%.In application demonstration,this triboelectric soft starter(TSS)has the capacity to gain a smooth operation of the high-speed motor.In contrast,the direct start generates an overshoot,leading to a break in the conveyor belt.The TSS designed in this work with the advantages of self-powered,highly integrated,easy to operate,and low cost,provides a prospective strategy for broadening the application of TENG in mechanical transmission systems.
基金supported by the National Natural Science Founda-tion of China(52277030)the China State Grid Corporation Science and Technology Project(DG71-16-002,DG71-18-004,DG71-22-006)the China State Grid Liaoning Electric Power Company Science and Technology Project(2019YF-63,2021YF-30).
文摘On August 4,2024,the first set of magnetobiased superconducting current limiters(MBSFCL)completed a 6-month grid-connected demonstration operation at the 66 kV Zhangtaizi substation in Liaoyang City,China.Moreover,it successfully limited the current dur-ing an actual three-phase short-circuit fault in a transmission line,thereby fully verifying the fault-current-limiting characteristics of the MBSFCL.This practical breakthrough signifies a noteworthy milestone in China’s power system,providing an innovative superconducting fault current-limiting solution for international urban power grids security[1].
