Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growt...Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation.Herein,a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid(ZEA)artificial film and ZnF2-rich solid electrolyte interphase(SEI)layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.The ZEA-based artificial film shows strong affinity for the ZnF2-rich SEI layer,therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode.Such double-layered architecture not only modulates Zn2+flux and suppresses the zinc dendrite growth,but also blocks the direct contact between the metal anode and electrolyte,thus mitigating the corrosion from the active species.When employing optimized metal anodes and electrolytes,the as-developed zinc-(dual)halogen batteries present high areal capacity and satisfactory cycling stability.This work provides a new avenue for developing aqueous zinc-(dual)halogen batteries.展开更多
The Hehuang Valley,situated in the northeastern section of the Qinghai-Tibet Plateau,represents the upper reaches of the Yellow River(Fig.1A).It is a significant geographic region of origin for numerous Neolithic cult...The Hehuang Valley,situated in the northeastern section of the Qinghai-Tibet Plateau,represents the upper reaches of the Yellow River(Fig.1A).It is a significant geographic region of origin for numerous Neolithic cultures,including the Majiayao,Zongri,and Qijia cultures(Dong et al.,2013).展开更多
Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan,the paper introduces the basic principle of transformer switch-in with load.EMTPE program that is use...Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan,the paper introduces the basic principle of transformer switch-in with load.EMTPE program that is used to establish a calculation model,at the same time mainly considers the excitation characteristics of the transformer,the transient model of the circuit breaker,and the model of high voltage transformer,and calculated the inrush current with transformer switch-in with load in this plan.During system debugging in the plan,the two sets of main transformers passed the closing and opening test,and the data of inrush current in the test are recorded and analyzed.The simulation calculation and measured data show that the results are consistent.The simulation calculation also shows that it is not recommended to perform on-load closing of the transformer except for special circumstances,because of the influence of hysteresis characteristic when the transformer was switched in with load or the terminal voltage of the transformer resumed normal level from a low one after an external near-end fault was cleared,which various transformer differential protection using the characteristics of inrush to implement block scheme may mal-operate.展开更多
Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low specific capacity,unstable cycling performance and sluggish reaction ki...Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low specific capacity,unstable cycling performance and sluggish reaction kinetics issues of rechargeable magnesium batteries(RMBs)by providing more active sites as well as releasing inner stress during cycling.Herein,WO_(3)@WO_(3-x)S_(x) owning crystalline@amorphous core-shell structure containing both active core and active shell is constructed successfully by introducing S into metastable WO3 structure under temperaturefield applying.In such structure,amorphous shell would provide continuous Mg^(2+)diffusion channels due to its isotropy property for most Mg^(2+)migrating rapidly to interface and then adsorb at ions reservoir formed by interfacial electricfield for increasing specific capacity.It also makes security for stable structure of WO_(3)@WO_(3-x)S_(x) by alleviating volume expansion of crystalline core WO_(3) during cycling to prolong cycling life.Additionally,“softer”ions S^(2-)would weaken interaction between hard acid Mg^(2+) and ionic lattice to enhance Mg^(2+)storage kinetics.Therefore,WO_(3)@WO_(3-x)S_(x) delivers the superior cycling performance(1000 cycles with 83.3%),rate capability(88.5 mAh g^(-1) at 1000 mA g^(-1))and specific capacity(about 150 mAh g^(-1) at 50 mA g^(-1)),which is near 2 times higher than that of WO3.It is believed that the crystalline@amorphous core-shell structure with both active core and shell designing via doping strategy is enlightening for the development of high-performance RMBs,and such design can be extended to other energy storage devices for better electrochemical performance.展开更多
Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-...Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas−liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents α1 and α2 are influenced by the viscous force. The values of pre-factors m_(1) and m_(2) are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.展开更多
A temperature and acoustic impedance simultaneous sensor based on forward stimulated Brillouin scattering(FSBS)in highly nonlinear fiber(HNLF)with high sensitivity and high accuracy is proposed and demonstrated in thi...A temperature and acoustic impedance simultaneous sensor based on forward stimulated Brillouin scattering(FSBS)in highly nonlinear fiber(HNLF)with high sensitivity and high accuracy is proposed and demonstrated in this paper.High-order acoustic modes(HOAMs)are used to achieve individual or simultaneous measurement of the two parameters.Transverse acoustic waves(TAWs)involved in the FSBS process can efficiently sense the mechanical or environmental changes outside the fiber cladding,which will be reflected in a linear shift of the acoustic resonance frequency.By analyzing the frequencies of specific scattering peaks,the temperature and acoustic impedance outside the fiber cladding can be obtained simultaneously.The highest measured temperature and acoustic impedance sensitivities are 184.93 k Hz/℃and444.56 k Hz/MRayl,and the measurement accuracies are 0.09℃and 0.009 MRayl,respectively,which are both at desirable levels.We believe this work can provide potential application solutions for sensing fields involving temperature or acoustic impedance measurements.展开更多
Microwave discharge plasma in liquid(MDPL)is a new type of water purification technology with a high mass transfer efficiency.It is a kind of low-temperature plasma technology.The reactive species produced by the disc...Microwave discharge plasma in liquid(MDPL)is a new type of water purification technology with a high mass transfer efficiency.It is a kind of low-temperature plasma technology.The reactive species produced by the discharge can efficiently act on the pollutants.To clarify the application prospects of MDPL in water treatment,the discharge performance,practical application,and pollutant degradation mechanism of MDPL were studied in this work.The effects of power,conductivity,pH,and Fe^(2+)concentration on the amount of reactive species produced by the discharge were explored.The most common and refractory perfluorinated compounds(perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)in water environments are degraded by MDPL technology.The highest defluorination of PFOA was 98.8% and the highest defluorination of PFOS was 92.7%.The energy consumption efficiency of 50% defluorination(G_(50-F))of PFOA degraded by MDPL is 78.43 mg/kWh,PFOS is 42.19 mg/kWh.The results show that the MDPL technology is more efficient and cleaner for the degradation of perfluorinated compounds.Finally,the reaction path and pollutant degradation mechanisms of MDPL production were analyzed.The results showed that MDPL technology can produce a variety of reactive species and has a good treatment effect for refractory perfluorinated pollutants.展开更多
GeTe-based alloys are promising thermoelectric materials for use at medium temperatures owing to their excellent thermoelectric performance.In this study,Ge_(0.8-x)Mn_(0.1)Pb_(0.1)Sb_(x)Te alloys were obtained via vac...GeTe-based alloys are promising thermoelectric materials for use at medium temperatures owing to their excellent thermoelectric performance.In this study,Ge_(0.8-x)Mn_(0.1)Pb_(0.1)Sb_(x)Te alloys were obtained via vacuum melting and hot-press sintering.Sb doping effectively decreased the carrier concentration,resulting in an enhancement of the Seebeck coefficient and consequently imparting excellent electrical transport performance to the sample.With doping concentration increasing,the structure of the sample changed from rhombohedral to cubic,creating a more favorable band structure for electronic transport properties.The incorporation of Sb into GeTe intensifies the lattice defects within the material.The significant decrease in the lattice thermal conductivity of the Ge_(0.71)Mn_(0.1)Pb_(0.1)Sb_(0.09)Te alloy to 0.84 W m^(-1)K^(-1)at 323 K is primarily attributed to the phonon scattering effect emanating from the presence of edge dislocation,point defects,and inherent grain boundaries.Finally,the maximum ZT value of the Ge_(0.74)Mn_(0.1)Pb_(0.1)Sb_(0.06)Te alloy was~1.53773 K,which is a significant enhancement of 0.35 compared to the undoped Ge_(0.8)Mn_(0.1)Pb_(0.1)Te alloy.This substantial improvement underscores the positive impact of the selected doping elements and their concentrations on the overall thermoelectric performance of the alloy.展开更多
The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate per...The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.展开更多
There are currently no targeted delivery systems to satisfactorily treat bone-related disorders.Many clinical drugs consisting of small organic molecules have a short circulation half-life and do not effectively reach...There are currently no targeted delivery systems to satisfactorily treat bone-related disorders.Many clinical drugs consisting of small organic molecules have a short circulation half-life and do not effectively reach the diseased tissue site.This coupled with repeatedly high dose usage that leads to severe side effects.展开更多
Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high perfo...Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.展开更多
As a crucial component of terrestrial ecosystems,urban forests play a pivotal role in protecting urban biodiversity by providing suitable habitats for acoustic spaces.Previous studies note that vegetation structure is...As a crucial component of terrestrial ecosystems,urban forests play a pivotal role in protecting urban biodiversity by providing suitable habitats for acoustic spaces.Previous studies note that vegetation structure is a key factor influencing bird sounds in urban forests;hence,adjusting the frequency composition may be a strategy for birds to avoid anthropogenic noise to mask their songs.However,it is unknown whether the response mechanisms of bird vocalizations to vegetation structure remain consistent despite being impacted by anthropogenic noise.It was hypothesized that anthropogenic noise in urban forests occupies the low-frequency space of bird songs,leading to a possible reshaping of the acoustic niches of forests,and the vegetation structure of urban forests is the critical factor that shapes the acoustic space for bird vocalization.Passive acoustic monitoring in various urban forests was used to monitor natural and anthropogenic noises,and sounds were classified into three acoustic scenes(bird sounds,human sounds,and bird-human sounds)to determine interconnections between bird sounds,anthropogenic noise,and vegetation structure.Anthropogenic noise altered the acoustic niche of urban forests by intruding into the low-frequency space used by birds,and vegetation structures related to volume(trunk volume and branch volume)and density(number of branches and leaf area index)significantly impact the diversity of bird sounds.Our findings indicate that the response to low and high frequency signals to vegetation structure is distinct.By clarifying this relationship,our results contribute to understanding of how vegetation structure influences bird sounds in urban forests impacted by anthropogenic noise.展开更多
Flexible thermoelectrics provide a distinct solution for developing sustainable and portable power supplies.Inorganic/organic material compositing is an effective strategy to induce a significant enhancement of thermo...Flexible thermoelectrics provide a distinct solution for developing sustainable and portable power supplies.Inorganic/organic material compositing is an effective strategy to induce a significant enhancement of thermoelectric(TE)performance.However,the poor electrical performance of inorganic/organic material is attributed to the poor carrier transport between organic/inorganic interfaces induced by the low contribution of composited inorganic materials.Herein,we prepared a high room temperature figure-of-merit(ZT)value of~0.19 and high bending resistance(surviving 1200 bending cycles at the bending radius of 16.5 mm)of p-type poly(3,4-ethylenedioxy thiophene):poly(4-styrenesulfonate)(PEDOT:PSS)/Bi_(0.5)Sb_(1.5)Te_(3)free-standing composite film via a facile vacuum-as sis ted filtration approach.Compositing Bi_(0.5)Sb_(1.5)Te_(3)nano-spherical particles into PEDOT:PSS results in the optimized interfacial contact and carrier concentration,leading to a high Seebeck coefficient of~43.79μV·K^(-1).Accordingly,a high-power factor of~1.52μW·cm^(-1)·K^(-2)is achieved in the PEDOT:PSS/Bi_(0.5)Sb_(1.5)Te_(3)composite film at room temperature.In addition,the PEDOT:PSS/Bi_(0.5)Sb_(1.5)Te_(3)interfaces with phase boundaries,nanograins and point defects could further decrease the thermal conductivity to~0.20 W·m^(-1)K^(-1),leading to a high ZT value.Furthermore,a 6-leg freestanding film device was assembled,which provided an output power of 44.94 nW.This study demonstrates that free-standing organic/inorganic composite films are effective power sources for wearable electronic products.展开更多
The variable selection of high dimensional nonparametric nonlinear systems aims to select the contributing variables or to eliminate the redundant variables.For a high dimensional nonparametric nonlinear system,howeve...The variable selection of high dimensional nonparametric nonlinear systems aims to select the contributing variables or to eliminate the redundant variables.For a high dimensional nonparametric nonlinear system,however,identifying whether a variable contributes or not is not easy.Therefore,based on the Fourier spectrum of densityweighted derivative,one novel variable selection approach is developed,which does not suffer from the dimensionality curse and improves the identification accuracy.Furthermore,a necessary and sufficient condition for testing a variable whether it contributes or not is provided.The proposed approach does not require strong assumptions on the distribution,such as elliptical distribution.The simulation study verifies the effectiveness of the novel variable selection algorithm.展开更多
AIM:To compare the consistency of two autorefractors(Tianle RM-9000 and Topcon KR-800)for school-age myopia children,and to provide a basis for largescale data analysis and comparison.METHODS:The refractive error in 9...AIM:To compare the consistency of two autorefractors(Tianle RM-9000 and Topcon KR-800)for school-age myopia children,and to provide a basis for largescale data analysis and comparison.METHODS:The refractive error in 909 subjects(age 4–18y)were measured using both autorefractors without cycloplegia.The data were analyzed using Fourier decomposition and the correlation coefficients,intraclass correlation coefficients(ICC),and Bland-Altman limits of agreement(LoA)for each parameter were calculated.RESULTS:There was a strong correlation between the spherical equivalent(SE),sphere diopter(DS),and cylinder diopter(DC)readings of the Tianle RM-9000 and those of the Topcon KR-800,with correlation coefficient values of 0.98,0.98 and 0.83 and ICC values of 0.99,0.99 and 0.93,respectively.However,the correlation coefficients and ICC values of J0 and J45 were unreliable(R=-0.004,-0.034;both ICC<0.10).Bland-Altman analysis revealed that SE,DS,and DC measured by the Tianle RM-9000 were significantly biased toward myopia compared with the Topcon KR-800,and the mean differences were-0.072,-0.026,-0.091 D,respectively(all P<0.01).The minimum absolute value of the difference within the 95%LoA for SE,DS,and DC was 0.63 D,0.50 D,0.62 D,respectively;all these values were in the clinically acceptable range.For J0 and J45,the mean differences were close to zero(P=0.43,0.84);however,the 95%LoA were relatively wide(J0 SD:0.53;95%CI:-1.00,1.10;J45 SD:0.52;95%CI:-1.00,1.00).CONCLUSION:The two autorefractors are consistent with each other,as the differences in SE,DS,and DC were within the clinically acceptable range.Readers can compare the data measured by either device in different studies and use the two devices in the same study to generate a dataset that can be analyzed together.However,the J0 and J45 vectors are unreliable and should not be used to assess astigmatism.展开更多
Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics,and organic cathode materials have become contenders for flex...Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics,and organic cathode materials have become contenders for flexible self-supporting electrodes.However,issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay.Herein,we have designed a flexible self-supporting cathode based on perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA),interfacial engineering enhanced by polypyrrole(PPy),and carbon nanotubes(CNTs),forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods,effectively curbing those challenges.When used as the cathode of sodium-ion batteries,PTCDA/PPy/CNTs exhibit excellent rate capability(105.7 mAh g^(−1) at 20 C),outstanding cycling stability(79.4%capacity retention at 5 C after 500 cycles),and remarkable wide temperature application capability(86.5 mAh g^(−1) at−30℃ and 115.4 mAh g^(−1) at 60℃).The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ions and carbonyl groups by density functional theory calculations,in situ infrared Fourier transform infrared spectroscopy,and in situ Raman spectroscopy.Surprisingly,the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states.This work inspires more rational designs of flexible and self-supporting organic cathodes,promoting the development of high-performance and wide-temperature adaptable wearable electronic devices.展开更多
Using the blood oxygen levels dependent technology of magnetic resonance imaging (BLOD-fMRI), we aimed to explore the brain activation after visual stimulation by Chinese words. In the current study, 24 healthy volunt...Using the blood oxygen levels dependent technology of magnetic resonance imaging (BLOD-fMRI), we aimed to explore the brain activation after visual stimulation by Chinese words. In the current study, 24 healthy volunteers (12 males, 12 females, right-handed, mean age 26 ± 2 years) were prospectively included. The event related design was used in the current fMRI study when participants silently read all words appearing in the middle of the screen. Images were processed with Statistical Parametric Mapping 8 (SPM8) software, by using a general linear model (GLM). Group activations were extracted from the 2nd level group analysis with a threshold of p < 0.001, and it was shown that the main activated areas by silent reading tasks were regions involved in brain semantic processing, including middle temporal gyrus, fusiform gyrus, supplementary motor area, inferior frontal gyrus, cingulate gyrus, superior parietal lobule and inferior parietal lobule. It was also learnt that superior parietal lobule and middle temporal gyrus are related with semantic understanding, lenticular nucleus are related with semantic processing. This means, in addition to the cerebral cortex, subcortical nuclei is also very important to the processing of words in Chinese language.展开更多
In this paper, the composition, two-dimensional and three-dimensional microstructure of heat-resistant wrought aluminum alloy with strong oxidation resistance, heat resistance and easy processing are analyzed by using...In this paper, the composition, two-dimensional and three-dimensional microstructure of heat-resistant wrought aluminum alloy with strong oxidation resistance, heat resistance and easy processing are analyzed by using direct reading spectrometer, metallographic microscope and scanning electron microscope. The main alloy elements of heat-resistant forging aluminum alloy include Cu, Mg, Si, Ni and Fe. The α solid solution of each element in aluminum consists of S phase (Al<sub>2</sub>CuMg), Mg<sub>2</sub>Si phase, bright gray Al<sub>2</sub>CuNi phase and dark brown Al<sub>9</sub>FeNi phase. The distribution of each phase in the aluminum alloy is determined by the three-dimensional energy spectrum analysis of the microstructure, and the distribution of each phase in the crystal position is analyzed. The mechanism of heat resistance, easy processing type and wear resistance is obtained, which provides the theoretical basis for the development and use of heat-resistant forged aluminum alloy.展开更多
基金support from the National Natural Science Foundation of China(22209089,22178187)Natural Science Foundation of Shandong Province(ZR2022QB048,ZR2021MB006)+2 种基金Excellent Youth Science Foundation of Shandong Province(Overseas)(2023HWYQ-089)the Taishan Scholars Program of Shandong Province(tsqn201909091)Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University.
文摘Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation.Herein,a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid(ZEA)artificial film and ZnF2-rich solid electrolyte interphase(SEI)layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.The ZEA-based artificial film shows strong affinity for the ZnF2-rich SEI layer,therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode.Such double-layered architecture not only modulates Zn2+flux and suppresses the zinc dendrite growth,but also blocks the direct contact between the metal anode and electrolyte,thus mitigating the corrosion from the active species.When employing optimized metal anodes and electrolytes,the as-developed zinc-(dual)halogen batteries present high areal capacity and satisfactory cycling stability.This work provides a new avenue for developing aqueous zinc-(dual)halogen batteries.
基金supported by the National Natural Science Foundation of China(42372017 and 42072018)the Fundamental Research Funds for the Central Universities(2022CXTD24)。
文摘The Hehuang Valley,situated in the northeastern section of the Qinghai-Tibet Plateau,represents the upper reaches of the Yellow River(Fig.1A).It is a significant geographic region of origin for numerous Neolithic cultures,including the Majiayao,Zongri,and Qijia cultures(Dong et al.,2013).
文摘Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan,the paper introduces the basic principle of transformer switch-in with load.EMTPE program that is used to establish a calculation model,at the same time mainly considers the excitation characteristics of the transformer,the transient model of the circuit breaker,and the model of high voltage transformer,and calculated the inrush current with transformer switch-in with load in this plan.During system debugging in the plan,the two sets of main transformers passed the closing and opening test,and the data of inrush current in the test are recorded and analyzed.The simulation calculation and measured data show that the results are consistent.The simulation calculation also shows that it is not recommended to perform on-load closing of the transformer except for special circumstances,because of the influence of hysteresis characteristic when the transformer was switched in with load or the terminal voltage of the transformer resumed normal level from a low one after an external near-end fault was cleared,which various transformer differential protection using the characteristics of inrush to implement block scheme may mal-operate.
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002200,52102106,52202262,22379081,22379080,Major Basic Research Program of Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09the Natural Science Foundation of Shandong Province under Grant No.ZR2020QE063,ZR202108180009,ZR2023QE059the Postdoctoral Program in Qingdao under No.QDBSH20220202019.
文摘Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low specific capacity,unstable cycling performance and sluggish reaction kinetics issues of rechargeable magnesium batteries(RMBs)by providing more active sites as well as releasing inner stress during cycling.Herein,WO_(3)@WO_(3-x)S_(x) owning crystalline@amorphous core-shell structure containing both active core and active shell is constructed successfully by introducing S into metastable WO3 structure under temperaturefield applying.In such structure,amorphous shell would provide continuous Mg^(2+)diffusion channels due to its isotropy property for most Mg^(2+)migrating rapidly to interface and then adsorb at ions reservoir formed by interfacial electricfield for increasing specific capacity.It also makes security for stable structure of WO_(3)@WO_(3-x)S_(x) by alleviating volume expansion of crystalline core WO_(3) during cycling to prolong cycling life.Additionally,“softer”ions S^(2-)would weaken interaction between hard acid Mg^(2+) and ionic lattice to enhance Mg^(2+)storage kinetics.Therefore,WO_(3)@WO_(3-x)S_(x) delivers the superior cycling performance(1000 cycles with 83.3%),rate capability(88.5 mAh g^(-1) at 1000 mA g^(-1))and specific capacity(about 150 mAh g^(-1) at 50 mA g^(-1)),which is near 2 times higher than that of WO3.It is believed that the crystalline@amorphous core-shell structure with both active core and shell designing via doping strategy is enlightening for the development of high-performance RMBs,and such design can be extended to other energy storage devices for better electrochemical performance.
基金supports for this project from State Key Laboratory of Chemical Safety(SKLCS–2024001)are gratefully acknowledged。
文摘Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas−liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents α1 and α2 are influenced by the viscous force. The values of pre-factors m_(1) and m_(2) are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.
文摘A temperature and acoustic impedance simultaneous sensor based on forward stimulated Brillouin scattering(FSBS)in highly nonlinear fiber(HNLF)with high sensitivity and high accuracy is proposed and demonstrated in this paper.High-order acoustic modes(HOAMs)are used to achieve individual or simultaneous measurement of the two parameters.Transverse acoustic waves(TAWs)involved in the FSBS process can efficiently sense the mechanical or environmental changes outside the fiber cladding,which will be reflected in a linear shift of the acoustic resonance frequency.By analyzing the frequencies of specific scattering peaks,the temperature and acoustic impedance outside the fiber cladding can be obtained simultaneously.The highest measured temperature and acoustic impedance sensitivities are 184.93 k Hz/℃and444.56 k Hz/MRayl,and the measurement accuracies are 0.09℃and 0.009 MRayl,respectively,which are both at desirable levels.We believe this work can provide potential application solutions for sensing fields involving temperature or acoustic impedance measurements.
基金supported by National Natural Science Foundation of China(Nos.12475258,12111530008 and 11675031)Major Scientific Research Project of Hebei Transportation Investment Group in 2024([202]155)the support of the Fundamental Research Funds for the Central Universities(No.3132023503)。
文摘Microwave discharge plasma in liquid(MDPL)is a new type of water purification technology with a high mass transfer efficiency.It is a kind of low-temperature plasma technology.The reactive species produced by the discharge can efficiently act on the pollutants.To clarify the application prospects of MDPL in water treatment,the discharge performance,practical application,and pollutant degradation mechanism of MDPL were studied in this work.The effects of power,conductivity,pH,and Fe^(2+)concentration on the amount of reactive species produced by the discharge were explored.The most common and refractory perfluorinated compounds(perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)in water environments are degraded by MDPL technology.The highest defluorination of PFOA was 98.8% and the highest defluorination of PFOS was 92.7%.The energy consumption efficiency of 50% defluorination(G_(50-F))of PFOA degraded by MDPL is 78.43 mg/kWh,PFOS is 42.19 mg/kWh.The results show that the MDPL technology is more efficient and cleaner for the degradation of perfluorinated compounds.Finally,the reaction path and pollutant degradation mechanisms of MDPL production were analyzed.The results showed that MDPL technology can produce a variety of reactive species and has a good treatment effect for refractory perfluorinated pollutants.
基金financially supported by the National Natural Science Foundation of China(Nos.12204355,52272210,12364006 and 12164011)the Open Project of State Key Laboratory of Superhard Materials,Jilin University(No.202110)the Natural Science Foundation of Shandong Province(Nos.ZR2022QA018,ZR2023QE282,ZR2023ME001 and ZR2023MF081)
文摘GeTe-based alloys are promising thermoelectric materials for use at medium temperatures owing to their excellent thermoelectric performance.In this study,Ge_(0.8-x)Mn_(0.1)Pb_(0.1)Sb_(x)Te alloys were obtained via vacuum melting and hot-press sintering.Sb doping effectively decreased the carrier concentration,resulting in an enhancement of the Seebeck coefficient and consequently imparting excellent electrical transport performance to the sample.With doping concentration increasing,the structure of the sample changed from rhombohedral to cubic,creating a more favorable band structure for electronic transport properties.The incorporation of Sb into GeTe intensifies the lattice defects within the material.The significant decrease in the lattice thermal conductivity of the Ge_(0.71)Mn_(0.1)Pb_(0.1)Sb_(0.09)Te alloy to 0.84 W m^(-1)K^(-1)at 323 K is primarily attributed to the phonon scattering effect emanating from the presence of edge dislocation,point defects,and inherent grain boundaries.Finally,the maximum ZT value of the Ge_(0.74)Mn_(0.1)Pb_(0.1)Sb_(0.06)Te alloy was~1.53773 K,which is a significant enhancement of 0.35 compared to the undoped Ge_(0.8)Mn_(0.1)Pb_(0.1)Te alloy.This substantial improvement underscores the positive impact of the selected doping elements and their concentrations on the overall thermoelectric performance of the alloy.
基金financially supported by the Australian Research Council(ARC) through the Future Fellowship(FT180100705)the financial support from China Scholarship Council+3 种基金the support from UTS-HUST Key Technology Partner Seed Fundthe support from Open Project of State Key Laboratory of Advanced Special Steel,the Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2021-04)the Science and Technology Commission of Shanghai Municipality(22010500400)“Joint International Laboratory on Environmental and Energy Frontier Materials”and“Innovation Research Team of High–Level Local Universities in Shanghai”in Shanghai University。
文摘The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.
基金financially supported by the National Natural Science Foundation of China (22305117)the Natural Science Foundation of Jiangsu Province (BK20220336)the Natural Science Foundation for Colleges and Universities in Jiangsu Province (22KJB180002)。
文摘There are currently no targeted delivery systems to satisfactorily treat bone-related disorders.Many clinical drugs consisting of small organic molecules have a short circulation half-life and do not effectively reach the diseased tissue site.This coupled with repeatedly high dose usage that leads to severe side effects.
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002200,52102106,52202262,22379081,and 22379080Major Basic Research Program of the Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09+1 种基金the Natural Science Foundation of Shandong Province under Grant No.ZR2020QE063,ZR202108180009,ZR2023QE059the Postdoctoral Program in Qingdao under No.QDBSH20220202019。
文摘Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.
基金the National Natural Science Foundation of China(32201338)Science Technology Program from the Forestry Administration of Guangdong Province(2021KJCX017)+1 种基金Guangzhou Municipal Science and Technology Bureau Program(2023A04J0086)Shenzhen Key Laboratory of Southern Subtropical Plant Diversity。
文摘As a crucial component of terrestrial ecosystems,urban forests play a pivotal role in protecting urban biodiversity by providing suitable habitats for acoustic spaces.Previous studies note that vegetation structure is a key factor influencing bird sounds in urban forests;hence,adjusting the frequency composition may be a strategy for birds to avoid anthropogenic noise to mask their songs.However,it is unknown whether the response mechanisms of bird vocalizations to vegetation structure remain consistent despite being impacted by anthropogenic noise.It was hypothesized that anthropogenic noise in urban forests occupies the low-frequency space of bird songs,leading to a possible reshaping of the acoustic niches of forests,and the vegetation structure of urban forests is the critical factor that shapes the acoustic space for bird vocalization.Passive acoustic monitoring in various urban forests was used to monitor natural and anthropogenic noises,and sounds were classified into three acoustic scenes(bird sounds,human sounds,and bird-human sounds)to determine interconnections between bird sounds,anthropogenic noise,and vegetation structure.Anthropogenic noise altered the acoustic niche of urban forests by intruding into the low-frequency space used by birds,and vegetation structures related to volume(trunk volume and branch volume)and density(number of branches and leaf area index)significantly impact the diversity of bird sounds.Our findings indicate that the response to low and high frequency signals to vegetation structure is distinct.By clarifying this relationship,our results contribute to understanding of how vegetation structure influences bird sounds in urban forests impacted by anthropogenic noise.
基金financially supported by the National Natural Science Foundation of China(Nos.12204355 and 52272210)the Natural Science Foundations of Shandong Province(Nos.ZR2023ME001 and ZR2022QA018)+1 种基金China Postdoctoral Science Foundation(No.2023M732609)the Doctoral Research Initiation Fund of Weifang University(Nos.2023BS01 and 2023BS06)。
文摘Flexible thermoelectrics provide a distinct solution for developing sustainable and portable power supplies.Inorganic/organic material compositing is an effective strategy to induce a significant enhancement of thermoelectric(TE)performance.However,the poor electrical performance of inorganic/organic material is attributed to the poor carrier transport between organic/inorganic interfaces induced by the low contribution of composited inorganic materials.Herein,we prepared a high room temperature figure-of-merit(ZT)value of~0.19 and high bending resistance(surviving 1200 bending cycles at the bending radius of 16.5 mm)of p-type poly(3,4-ethylenedioxy thiophene):poly(4-styrenesulfonate)(PEDOT:PSS)/Bi_(0.5)Sb_(1.5)Te_(3)free-standing composite film via a facile vacuum-as sis ted filtration approach.Compositing Bi_(0.5)Sb_(1.5)Te_(3)nano-spherical particles into PEDOT:PSS results in the optimized interfacial contact and carrier concentration,leading to a high Seebeck coefficient of~43.79μV·K^(-1).Accordingly,a high-power factor of~1.52μW·cm^(-1)·K^(-2)is achieved in the PEDOT:PSS/Bi_(0.5)Sb_(1.5)Te_(3)composite film at room temperature.In addition,the PEDOT:PSS/Bi_(0.5)Sb_(1.5)Te_(3)interfaces with phase boundaries,nanograins and point defects could further decrease the thermal conductivity to~0.20 W·m^(-1)K^(-1),leading to a high ZT value.Furthermore,a 6-leg freestanding film device was assembled,which provided an output power of 44.94 nW.This study demonstrates that free-standing organic/inorganic composite films are effective power sources for wearable electronic products.
基金Project supported by the National Key Research and Development Program of China(No.2021YFB3400700)the National Natural Science Foundation of China(Nos.12422201,12072188,12121002,and 12372017)。
文摘The variable selection of high dimensional nonparametric nonlinear systems aims to select the contributing variables or to eliminate the redundant variables.For a high dimensional nonparametric nonlinear system,however,identifying whether a variable contributes or not is not easy.Therefore,based on the Fourier spectrum of densityweighted derivative,one novel variable selection approach is developed,which does not suffer from the dimensionality curse and improves the identification accuracy.Furthermore,a necessary and sufficient condition for testing a variable whether it contributes or not is provided.The proposed approach does not require strong assumptions on the distribution,such as elliptical distribution.The simulation study verifies the effectiveness of the novel variable selection algorithm.
基金Supported by the National Natural Science Foundation of China(No.81873683).
文摘AIM:To compare the consistency of two autorefractors(Tianle RM-9000 and Topcon KR-800)for school-age myopia children,and to provide a basis for largescale data analysis and comparison.METHODS:The refractive error in 909 subjects(age 4–18y)were measured using both autorefractors without cycloplegia.The data were analyzed using Fourier decomposition and the correlation coefficients,intraclass correlation coefficients(ICC),and Bland-Altman limits of agreement(LoA)for each parameter were calculated.RESULTS:There was a strong correlation between the spherical equivalent(SE),sphere diopter(DS),and cylinder diopter(DC)readings of the Tianle RM-9000 and those of the Topcon KR-800,with correlation coefficient values of 0.98,0.98 and 0.83 and ICC values of 0.99,0.99 and 0.93,respectively.However,the correlation coefficients and ICC values of J0 and J45 were unreliable(R=-0.004,-0.034;both ICC<0.10).Bland-Altman analysis revealed that SE,DS,and DC measured by the Tianle RM-9000 were significantly biased toward myopia compared with the Topcon KR-800,and the mean differences were-0.072,-0.026,-0.091 D,respectively(all P<0.01).The minimum absolute value of the difference within the 95%LoA for SE,DS,and DC was 0.63 D,0.50 D,0.62 D,respectively;all these values were in the clinically acceptable range.For J0 and J45,the mean differences were close to zero(P=0.43,0.84);however,the 95%LoA were relatively wide(J0 SD:0.53;95%CI:-1.00,1.10;J45 SD:0.52;95%CI:-1.00,1.00).CONCLUSION:The two autorefractors are consistent with each other,as the differences in SE,DS,and DC were within the clinically acceptable range.Readers can compare the data measured by either device in different studies and use the two devices in the same study to generate a dataset that can be analyzed together.However,the J0 and J45 vectors are unreliable and should not be used to assess astigmatism.
基金Shuangqiang Chen gratefully acknowledges the NationalNatural Science Foundation ofChina(21975154,22179078)Zhejiang Provincial Natural Science Founda-tion of China(LY24E020002)+3 种基金Shanghai MunicipalEducation Commission(Innovation Program:2019-01-07-00-09-E00021)the Innovative Research Team of High-level Local Universities in Shanghai.Bing Sunwould like to thank the financial support from ARCthrough the ARC Future Fellowship(FT220100561)YaoXiao would like to thank the financial support from theNatural Science Foundation of Zhejiang Province(LQ23E020002)the Wenzhou Key Scientific andTechnological Innovation Research Project(ZG2023053)
文摘Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics,and organic cathode materials have become contenders for flexible self-supporting electrodes.However,issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay.Herein,we have designed a flexible self-supporting cathode based on perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA),interfacial engineering enhanced by polypyrrole(PPy),and carbon nanotubes(CNTs),forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods,effectively curbing those challenges.When used as the cathode of sodium-ion batteries,PTCDA/PPy/CNTs exhibit excellent rate capability(105.7 mAh g^(−1) at 20 C),outstanding cycling stability(79.4%capacity retention at 5 C after 500 cycles),and remarkable wide temperature application capability(86.5 mAh g^(−1) at−30℃ and 115.4 mAh g^(−1) at 60℃).The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ions and carbonyl groups by density functional theory calculations,in situ infrared Fourier transform infrared spectroscopy,and in situ Raman spectroscopy.Surprisingly,the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states.This work inspires more rational designs of flexible and self-supporting organic cathodes,promoting the development of high-performance and wide-temperature adaptable wearable electronic devices.
文摘Using the blood oxygen levels dependent technology of magnetic resonance imaging (BLOD-fMRI), we aimed to explore the brain activation after visual stimulation by Chinese words. In the current study, 24 healthy volunteers (12 males, 12 females, right-handed, mean age 26 ± 2 years) were prospectively included. The event related design was used in the current fMRI study when participants silently read all words appearing in the middle of the screen. Images were processed with Statistical Parametric Mapping 8 (SPM8) software, by using a general linear model (GLM). Group activations were extracted from the 2nd level group analysis with a threshold of p < 0.001, and it was shown that the main activated areas by silent reading tasks were regions involved in brain semantic processing, including middle temporal gyrus, fusiform gyrus, supplementary motor area, inferior frontal gyrus, cingulate gyrus, superior parietal lobule and inferior parietal lobule. It was also learnt that superior parietal lobule and middle temporal gyrus are related with semantic understanding, lenticular nucleus are related with semantic processing. This means, in addition to the cerebral cortex, subcortical nuclei is also very important to the processing of words in Chinese language.
文摘In this paper, the composition, two-dimensional and three-dimensional microstructure of heat-resistant wrought aluminum alloy with strong oxidation resistance, heat resistance and easy processing are analyzed by using direct reading spectrometer, metallographic microscope and scanning electron microscope. The main alloy elements of heat-resistant forging aluminum alloy include Cu, Mg, Si, Ni and Fe. The α solid solution of each element in aluminum consists of S phase (Al<sub>2</sub>CuMg), Mg<sub>2</sub>Si phase, bright gray Al<sub>2</sub>CuNi phase and dark brown Al<sub>9</sub>FeNi phase. The distribution of each phase in the aluminum alloy is determined by the three-dimensional energy spectrum analysis of the microstructure, and the distribution of each phase in the crystal position is analyzed. The mechanism of heat resistance, easy processing type and wear resistance is obtained, which provides the theoretical basis for the development and use of heat-resistant forged aluminum alloy.
