In this paper,we study the optimal investment problem of an insurer whose surplus process follows the diffusion approximation of the classical Cramer-Lundberg model.Investment in the foreign markets is allowed,and the...In this paper,we study the optimal investment problem of an insurer whose surplus process follows the diffusion approximation of the classical Cramer-Lundberg model.Investment in the foreign markets is allowed,and therefore,the foreign exchange rate model is incorporated.Under the allowing of selling and borrowing,the problem of maximizing the expected exponential utility of terminal wealth is studied.By solving the corresponding Hamilton-Jacobi-Bellman equations,the optimal investment strategies and value functions are obtained.Finally,numerical analysis is presented.展开更多
The tensile strain in inorganic perovskite films induced by thermal annealing is one of the primary factors contributing to the inefficiency and instability of inorganic perovskite solar cells(IPSCs),which reduces the...The tensile strain in inorganic perovskite films induced by thermal annealing is one of the primary factors contributing to the inefficiency and instability of inorganic perovskite solar cells(IPSCs),which reduces the defect formation energy.Here,a flexible molecule 5-maleimidovaleric acid(5-MVA)was introduced as a strain buffer to release the residual strain of CsPbI_(2.85)Br_(0.15)perovskite.Maleic anhydride and carboxyl groups in 5-MVA interact strongly with the uncoordinated Pb^(2+)through Lewis acid-base reaction,thus tightly“pull”the perovskite lattice.The in-between soft carbon chain increased the structural flexibility of CsPbI_(2.85)Br_(0.15)perovskite materials,which effectively relieved the intrinsic internal strain of CsPbI_(2.85)Br_(0.15),resisted the corrosion of external strain,and also reduced the formation of defects such as VIand Pb0.In addition,the introduction of 5-MVA improved crystal quality,passivated residual defects,and narrowed energy level barriers.Eventually,power conversion efficiency(PCE)of NiOxbased inverted IPSCs increased from 19.25%to 20.82%with the open-circuit voltage enhanced from 1.164 V to 1.230 V.The release of strain also improved the stability of CsPbI_(2.85)Br_(0.15)perovskite films and devices.展开更多
Fused silica(SiO_(2)glass),a key amorphous component of Earth’s silicate minerals,undergoes coordination and phase transformations under high pressure.Although extensive studies have been conducted,discrepancies betw...Fused silica(SiO_(2)glass),a key amorphous component of Earth’s silicate minerals,undergoes coordination and phase transformations under high pressure.Although extensive studies have been conducted,discrepancies between theoretical and experimental studies remain,particularly regarding strain rate effects during compression.Here,we examine strain rate influences on the shock-induced amorphous–amorphous phase transitions in fused silica by measuring its Hugoniot equation of state and longitudinal sound velocity(CL)up to 7 GPa at strain rates of 10^(6)–10^(7)s^(-1)using a one-stage light-gas gun.A discontinuity in the relationship between shock velocity(US)and particle velocity(UP)and a significant softening in C_(L)of fused silica were observed near~5 GPa under shock loading.Our results indicate that high strain rates restrict Si–O–Si rotation in fused silica,modifying their bonds and increasing silicon coordination.The transition pressure by shock compression is significantly higher than that under static high-pressure conditions(2–3 GPa),which agrees with some recent theoretical predictions with high compression rates,reflecting the greater pressure needed to overcome energy barriers with the strain rate increase.These findings offer insights into strain rate-dependent phase transitions in fused silica and other silicate minerals(e.g.,quartz,olivine,and forsterite),bridging gaps between theoretical simulations and experiments.展开更多
To address the contradiction between the explosive growth of wireless data and the limited spectrum resources,semantic communication has been emerging as a promising communication paradigm.In this paper,we thus design...To address the contradiction between the explosive growth of wireless data and the limited spectrum resources,semantic communication has been emerging as a promising communication paradigm.In this paper,we thus design a speech semantic coded communication system,referred to as Deep-STS(i.e.,Deep-learning based Speech To Speech),for the lowbandwidth speech communication.Specifically,we first deeply compress the speech data through extracting the textual information from the speech based on the conformer encoder and connectionist temporal classification decoder at the transmitter side of Deep-STS system.In order to facilitate the final speech timbre recovery,we also extract the short-term timbre feature of speech signals only for the starting 2s duration by the long short-term memory network.Then,the Reed-Solomon coding and hybrid automatic repeat request protocol are applied to improve the reliability of transmitting the extracted text and timbre feature over the wireless channel.Third,we reconstruct the speech signal by the mel spectrogram prediction network and vocoder,when the extracted text is received along with the timbre feature at the receiver of Deep-STS system.Finally,we develop the demo system based on the USRP and GNU radio for the performance evaluation of Deep-STS.Numerical results show that the ac-Received:Jan.17,2024 Revised:Jun.12,2024 Editor:Niu Kai curacy of text extraction approaches 95%,and the mel cepstral distortion between the recovered speech signal and the original one in the spectrum domain is less than 10.Furthermore,the experimental results show that the proposed Deep-STS system can reduce the total delay of speech communication by 85%on average compared to the G.723 coding at the transmission rate of 5.4 kbps.More importantly,the coding rate of the proposed Deep-STS system is extremely low,only 0.2 kbps for continuous speech communication.It is worth noting that the Deep-STS with lower coding rate can support the low-zero-power speech communication,unveiling a new era in ultra-efficient coded communications.展开更多
Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination...Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubuleattachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data,we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.展开更多
To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.T...To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.The methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface sources.To address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration methods.These methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically evaluated.Finally,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface source.In situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.展开更多
This paper studies the global existence and large-time behaviors of weak solutions to the kinetic particle model coupled with the incompressible Navier-Stokes equations in IR3.First,we obtain the global weak solution ...This paper studies the global existence and large-time behaviors of weak solutions to the kinetic particle model coupled with the incompressible Navier-Stokes equations in IR3.First,we obtain the global weak solution using the characteristic and energy methods.Then,under the small assumption of the mass of the particle,we show that the solutions decay at the algebraic time-decay rate.Finally,it is also proved that the above rate is optimal.It should be remarked that if the particle in the coupled system vanishes(i.e.f=O),our works coincide with the classical results by Schonbek[32](J Amer Math Soc,1991,4:423-449),which can be regarded as a generalization from a single fuid model to the two-phase fluid one.展开更多
Aiming at the gas discharge problem in electric aircraft,this work studies the gas discharge characteristics at low-temperature sub-atmospheric pressure.A gas discharge shooting platform was built,and the discharge pr...Aiming at the gas discharge problem in electric aircraft,this work studies the gas discharge characteristics at low-temperature sub-atmospheric pressure.A gas discharge shooting platform was built,and the discharge process was photographed by intensified charge-coupled device(ICCD).A two-dimensional axisymmetric model of needle-plate electrode gas discharge was established,and three sets of Helmholtz equations were used to solve the photoionization.The results show that under the same voltage,the electric field intensity in the discharge process increases first,then decreases and finally increases again.The discharge speed increases with the increase of altitude,and the electron density in the streamer decreases with the increase of altitude.The development speed of the streamer in the middle stage is higher than that in the early stage,and the speed increases more obviously with the increase of altitude.The development speed of the streamer in the later stage is lower than that in the middle stage,but with the increase of altitude,the development speed of the streamer in the later stage is higher than that in the middle stage.展开更多
The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved. Taking Chengchao Iron Mine as the engineering background, the model for analyzing the instability...The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved. Taking Chengchao Iron Mine as the engineering background, the model for analyzing the instability of deep gob was established based on the mechanism of stress relief in deep mining.The energy evolution law was analyzed by introducing the local energy release rate index(LERR), and the energy criterion of the instability of surrounding rock was established based on the cusp catastrophe theory. The results show that the evolution equation of the local energy release of the surrounding rock is a quartic function with one unknown and the release rate increases gradually during the mining process.The calculation results show that the gob is stable. The LERR per unit volume of the bottom structure is relatively smaller which means that the stability is better. The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meets the characteristics of deep mining. In summary, this model could effectively calculate the stability of surrounding rock in the formation of gob. The LERR could reflect the dynamic process of energy release,transfer and dissipation and that provided an important reference for the study of the stability of deep mined out area.展开更多
Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was ad...Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was adopted to monitor the failure process of coal samples. The study of the change rule of the AE numbers, energy, ‘b' value and spectrum in the micro crack propagation process of the coal samples shows that as dynamic damage time went by, AE presented high-energy counts and the accumulated counts increased during the compression phase. The AE energy and cumulative counts increased during the elastic stage. The AE blank area increased gradually and the blank lines were more and more obvious in the molding stage. The AE counts and energy showed a trend of decrease in the residual damage phase.AE ‘b' values gradually became sparse, and the large scale cracks percentage compared with micro cracks decreased and the degree of damage decreased. The AE frequency spectrum peak went from the residual damage phase to the molding phase, and finally it was nearly stable, besides the bandwidth of the main frequency is gradually narrowed. Also, the frequency peak changed from single peak frequency to bi-peak frequency and to the single peak frequency. Uniaxial compressive strength is more sensitive than the elastic modulus to dynamic damage time.展开更多
Enhancement release has been proven effective in natural resources recovery of Chinese shrimp Fenneropenaeus chinensis in the last several decades in China, however, to assess the effectiveness of enhancement release,...Enhancement release has been proven effective in natural resources recovery of Chinese shrimp Fenneropenaeus chinensis in the last several decades in China, however, to assess the effectiveness of enhancement release, we still need to develop a high-efficient and easy-operational method to replace those physical-tagging release method with labor intensive, size-and number-limited. In the present study, single(with maternal known) parentage identification using eight simple sequence repeat(SSR) markers genotype fingerprint was used to trace Chinese shrimp released in Bohai Bay in 2013. A total of 884 shrimp spawners were collected from two hatcheries in Tianjin City respectively after enhancement release of shrimp larvae in May 2013. A total of 844 shrimp samples were recaptured around the release location approximately 4 months after the shrimp larvae were released into the natural sea. Genotype data of 8 SSR loci of the 1,726 samples were used for maternal-offspring parentage identification using CEervus 3.0 software. The allele number in each locus ranged from 8 to 68 with an average value of 33.25, which produced the cumulative exclusion probability with one parent known of all these sight loci up to 99%. Among the 844 recaptured shrimp samples, 448(♂:♀=212:232, gender information was lost for 4 samples) were successfully traced to their 337 maternal parents using a logarithm of odds(LOD) > 3.0 threshold. Among these 337 maternal parents, 253 had a single offspring, 62 had two offspring, 18 had three offspring, 3 had four offspring, and 1 had five offspring. For the first time, a large number of released shrimp were identified from recapture samples, and this study showed that it is possible to trace all released Chinese shrimp without using any type of physical tag in enhancement release activities. This not only means more precise recapture ratio assessment than ever expected, but also this method demonstrates an effective method for large-scale hatchery release as well as for organisms used in hatchery enhancement which are not suitable for physical tagging.展开更多
Stimuli-triggered drug delivery systems hold vast promise in local infection treatment for the site-specific targeting and shuttling of drugs.Herein,chitosan conjugates(SPCS)installed with sialic acid(SA)and phenylbor...Stimuli-triggered drug delivery systems hold vast promise in local infection treatment for the site-specific targeting and shuttling of drugs.Herein,chitosan conjugates(SPCS)installed with sialic acid(SA)and phenylboronic acid(PBA)were synthesized,of which SA served as targeting ligand for coccidium and reversible-binding bridge for PBA.The enhanced drug-loading capacity of SPCS micelles was attributed to a combination assembly from hydrophobicity-driving and reversible borate bridges.The drug-loaded SPCS micelles shared superior biostability in upper gastrointestinal tract.After reaching the lesions,the borate bridges were snipped by carbohydrates under a higher pH followed by accelerated drug release,while SA exposure on micellar surface facilitated drug cellular internalization to eliminate parasites inside.The drugmicelles revealed an enhanced anti-coccidial capacity with a higher index of 185.72 compared with commercial preparation.The dual-responsive combination of physicochemical assembly could provide an efficient strategy for the exploitation of stable,safe and flexible anti-infectious drug delivery systems.展开更多
The unreasonable observation arrangements in the satellite operation control center(SOCC)may result in the observation data cannot be downloaded as scheduled.Meanwhile,if the operation instructions released by the sat...The unreasonable observation arrangements in the satellite operation control center(SOCC)may result in the observation data cannot be downloaded as scheduled.Meanwhile,if the operation instructions released by the satellite telemetry tracking center(STTC)for the on-board payloads are not injected on the specific satellites in time,the corresponding satellites cannot perform the observation operations as planned.Therefore,there is an urgent need to design an integrated instruction release,and observation task planning(I-IRO-TP)scheme by efficiently collaborating the SOCC and STTC.Motivated by this fact,we design an interaction mechanism between the SOCC and the STTC,where we first formulate the I-IRO-TP problem as a constraint satisfaction problem aiming at maximizing the number of completed tasks.Furthermore,we propose an interactive imaging task planning algorithm based on the analysis of resource distribution in the STTC during the previous planning periods to preferentially select the observation arcs that not only satisfy the requirements in the observation resource allocation phase but also facilitate the arrangement of measurement and control instruction release.We conduct extensive simulations to demonstrate the effectiveness of the proposed algorithm in terms of the number of completed tasks.展开更多
The design and manufacture of anti-scaling surface is a prospective way to prevent scaling in oil field.In this work,a novel superhydrophobic Cu^(2+)-loaded and DTPMPA-modified anodized copper oxide(S-Cu^(2+)/D-ACO)co...The design and manufacture of anti-scaling surface is a prospective way to prevent scaling in oil field.In this work,a novel superhydrophobic Cu^(2+)-loaded and DTPMPA-modified anodized copper oxide(S-Cu^(2+)/D-ACO)coating was fabricated by modification of 1H,1H,2H,2H-perfluorodecyltriethoxysilane.The valid storing of scale inhibitors at the coating surface and the interfacial release of Cu^(2+)ions contribute to enhancing the anti-scaling of the S-Cu^(2+)/D-ACO coating.The water contact angle of the S-Cu^(2+)/D-ACO coating is 163.03°and exhibits superhydrophobicity,which makes it difficult for CaCO_(3)to deposit at the surface of the coating.DTPMPA will steadily lurk into the inner space,and Cu^(2+)will be loaded at the interface in the form of the DTPMPA:Cu^(2+)chelate.During the deposition of CaCO_(3),the dynamic release of DTPMPA can be realized by transferring DTPMPA:Cu^(2+)to DTPMPA:Ca^(2+).Interestingly,the released Cu^(2+)hinders the active growth of CaCO_(3).After 48 h of scaling,the mass of CaCO_(3)scale at the S-Cu^(2+)/D-ACO coating surface is only 44.1%that of the anodized copper oxide coating.The excellent anti-scaling performance of the S-Cu^(2+)/D-ACO coating is determined by the synergistic effect of the DTPMPA lurking and dynamic release,as well as the Cu^(2+)inhibition at the interface of superhydrophobic coating and against CaCO_(3)deposition.This research provides a new exploration for designing and fabricating anti-scaling superhydrophobic surface for oil field development.展开更多
Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,...Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.展开更多
In this paper,we study the one-dimensional motion of viscous gas near a vacuum,with the gas connecting to a vacuum state with a jump in density.The interface behavior,the pointwise decay rates of the density function ...In this paper,we study the one-dimensional motion of viscous gas near a vacuum,with the gas connecting to a vacuum state with a jump in density.The interface behavior,the pointwise decay rates of the density function and the expanding rates of the interface are obtained with the viscosity coefficientμ(ρ)=ρ^(α)for any 0<α<1;this includes the timeweighted boundedness from below and above.The smoothness of the solution is discussed.Moreover,we construct a class of self-similar classical solutions which exhibit some interesting properties,such as optimal estimates.The present paper extends the results in[Luo T,Xin Z P,Yang T.SIAM J Math Anal,2000,31(6):1175-1191]to the jump boundary conditions case with density-dependent viscosity.展开更多
The engineering of plant-based precursor for nitrogen doping has become one of the most promising strategies to enhance rate capability of hard carbon materials for sodium-ion batteries;however,the poor rate performan...The engineering of plant-based precursor for nitrogen doping has become one of the most promising strategies to enhance rate capability of hard carbon materials for sodium-ion batteries;however,the poor rate performance is mainly caused by lack of pyridine nitrogen,which often tends to escape because of high temperature in preparation process of hard carbon.In this paper,a high-rate kapok fiber-derived hard carbon is fabricated by cross-linking carboxyl group in 2,6-pyridinedicarboxylic acid with the exposed hydroxyl group on alkalized kapok with assistance of zinc chloride.Specially,a high nitrogen doping content of 4.24%is achieved,most of which are pyridine nitrogen;this is crucial for improving the defect sites and electronic conductivity of hard carbon.The optimized carbon with feature of high nitrogen content,abundant functional groups,degree of disorder,and large layer spacing exhibits high capacity of 401.7 mAh g^(−1)at a current density of 0.05 A g^(−1),and more importantly,good rate performance,for example,even at the current density of 2 A g^(−1),a specific capacity of 159.5 mAh g^(−1)can be obtained.These findings make plant-based hard carbon a promising candidate for commercial application of sodium-ion batteries,achieving high-rate performance with the enhanced pre-cross-linking interaction between plant precursors and dopants to optimize aromatization process by auxiliary pyrolysis.展开更多
Titanium hydride(TiH_(2)), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types ...Titanium hydride(TiH_(2)), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types of PTFE/Al/TiH_(2) reactive liners with different TiH_(2) content are prepared by the molding and sintering method. The energy release characteristics of PTFE/Al/TiH_(2) reactive jet are tested by the transient explosion energy test, and are characterized from pressure and temperature. The reaction delay time,pressure history, and temperature history of the energy release process are obtained, then the actual value of released energy and reaction efficiency of the reactive jet are calculated. The results show that the peak pressure and temperature of the PTFE/Al/TiH_(2) jet initially increase and then decrease with increasing TiH_(2) content. When the TiH_(2) content is 10%, the actual value of released energy and reaction efficiency increased by 24% and 6.4%, respectively, compared to the PTFE/Al jet. The reaction duration of the reactive material is significantly prolonged as the TiH_(2) content increased from 0% to 30%. Finally,combined with the energy release behaviors of PAT material and the dynamic deformation process of liner, the enhancement mechanism of TiH_(2) on energy release of the reactive jet is expounded.展开更多
An OH^--slow-release strategy was established to controllably tune the( α-and β-) phase of nickel cobalt binary hydroxide in the presence of ammonium chloride. Ammonium chloride is added to the ionic solution to reg...An OH^--slow-release strategy was established to controllably tune the( α-and β-) phase of nickel cobalt binary hydroxide in the presence of ammonium chloride. Ammonium chloride is added to the ionic solution to regulate the p H of the solution and slow down the release of OH^-, effectively regulating the phase, nanostructure, interlayer spacing, surface area, thickness, and the performance of binary Ni –Co hydroxide. The ion-slow-release mechanism is conducive to the formation of α-phase with larger interlayer spacing and thinner flakes rather than β-phase. Attributed to the enlarged interlayer spacing, thinner nanosheets, and more exposed active sites, the resultant α-phase hydroxides(NCNS-5.2), displayed much lower over potential of 285 mV with respect to the dense-stacked β-phase hydroxides(362 mV) for OER at 10 mA/cm^2. It also exhibited high specific capacitance of 1474.2 F/g, when tested at 0.5 A/g within a voltage range of 0–0.45 Vvs. Hg/Hg O. This composite was also stable for water oxidation reaction and supercapacitor. The proof-of-concept of using controlled-release agent may provide suggestive insights for the material innovation and a variety of applications.展开更多
The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 MHz.Kicker magnets are key components that distribute electron bunches into three...The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 MHz.Kicker magnets are key components that distribute electron bunches into three different undulator lines in a bunch-by-bunch mode.The kicker field width must be less than the time interval between bunches.A lumpedinductance kicker prototype was developed using a vacuum chamber with a single-turn coil.The full magnetic field strength was 0.005 T.This paper presents the requirements,design considerations,design parameters,magnetic field calculations,and measurements of the kicker magnets.The relevant experimental results are also presented.The pulse width of the magnetic field was approximately 600 ns,and the maximum operation repetition rate was 1 MHz.The developed kicker satisfies the requirements for the SHINE project.Finally,numerous recommendations for the future optimization of kicker magnets are provided.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12301603).
文摘In this paper,we study the optimal investment problem of an insurer whose surplus process follows the diffusion approximation of the classical Cramer-Lundberg model.Investment in the foreign markets is allowed,and therefore,the foreign exchange rate model is incorporated.Under the allowing of selling and borrowing,the problem of maximizing the expected exponential utility of terminal wealth is studied.By solving the corresponding Hamilton-Jacobi-Bellman equations,the optimal investment strategies and value functions are obtained.Finally,numerical analysis is presented.
基金financial support of National Key Research and Development Program of China(Grant No.2022YFB04200302)joint funds of National Natural Science Foundation of China(Grant No.62104115)+5 种基金National Natural Science Foundation of China(Grant No.U21A2072)Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China(Grant No.B16027)Key R&D Program of Hebei Province(No.19214301D)Yunnan Provincial Science and Technology Project at Southwest United Graduate School(No.202302A0370009)Haihe Laboratory of Sustainable Chemical TransformationsFundamental Research Funds for the Central Universities,Nankai University。
文摘The tensile strain in inorganic perovskite films induced by thermal annealing is one of the primary factors contributing to the inefficiency and instability of inorganic perovskite solar cells(IPSCs),which reduces the defect formation energy.Here,a flexible molecule 5-maleimidovaleric acid(5-MVA)was introduced as a strain buffer to release the residual strain of CsPbI_(2.85)Br_(0.15)perovskite.Maleic anhydride and carboxyl groups in 5-MVA interact strongly with the uncoordinated Pb^(2+)through Lewis acid-base reaction,thus tightly“pull”the perovskite lattice.The in-between soft carbon chain increased the structural flexibility of CsPbI_(2.85)Br_(0.15)perovskite materials,which effectively relieved the intrinsic internal strain of CsPbI_(2.85)Br_(0.15),resisted the corrosion of external strain,and also reduced the formation of defects such as VIand Pb0.In addition,the introduction of 5-MVA improved crystal quality,passivated residual defects,and narrowed energy level barriers.Eventually,power conversion efficiency(PCE)of NiOxbased inverted IPSCs increased from 19.25%to 20.82%with the open-circuit voltage enhanced from 1.164 V to 1.230 V.The release of strain also improved the stability of CsPbI_(2.85)Br_(0.15)perovskite films and devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.42422201,12175211,and 12350710177)the Sichuan Science and Technology Program(Grant No.2023NSFSC1910).
文摘Fused silica(SiO_(2)glass),a key amorphous component of Earth’s silicate minerals,undergoes coordination and phase transformations under high pressure.Although extensive studies have been conducted,discrepancies between theoretical and experimental studies remain,particularly regarding strain rate effects during compression.Here,we examine strain rate influences on the shock-induced amorphous–amorphous phase transitions in fused silica by measuring its Hugoniot equation of state and longitudinal sound velocity(CL)up to 7 GPa at strain rates of 10^(6)–10^(7)s^(-1)using a one-stage light-gas gun.A discontinuity in the relationship between shock velocity(US)and particle velocity(UP)and a significant softening in C_(L)of fused silica were observed near~5 GPa under shock loading.Our results indicate that high strain rates restrict Si–O–Si rotation in fused silica,modifying their bonds and increasing silicon coordination.The transition pressure by shock compression is significantly higher than that under static high-pressure conditions(2–3 GPa),which agrees with some recent theoretical predictions with high compression rates,reflecting the greater pressure needed to overcome energy barriers with the strain rate increase.These findings offer insights into strain rate-dependent phase transitions in fused silica and other silicate minerals(e.g.,quartz,olivine,and forsterite),bridging gaps between theoretical simulations and experiments.
基金supported in part by National Natural Science Foundation of China under Grants 62122069,62071431,and 62201507.
文摘To address the contradiction between the explosive growth of wireless data and the limited spectrum resources,semantic communication has been emerging as a promising communication paradigm.In this paper,we thus design a speech semantic coded communication system,referred to as Deep-STS(i.e.,Deep-learning based Speech To Speech),for the lowbandwidth speech communication.Specifically,we first deeply compress the speech data through extracting the textual information from the speech based on the conformer encoder and connectionist temporal classification decoder at the transmitter side of Deep-STS system.In order to facilitate the final speech timbre recovery,we also extract the short-term timbre feature of speech signals only for the starting 2s duration by the long short-term memory network.Then,the Reed-Solomon coding and hybrid automatic repeat request protocol are applied to improve the reliability of transmitting the extracted text and timbre feature over the wireless channel.Third,we reconstruct the speech signal by the mel spectrogram prediction network and vocoder,when the extracted text is received along with the timbre feature at the receiver of Deep-STS system.Finally,we develop the demo system based on the USRP and GNU radio for the performance evaluation of Deep-STS.Numerical results show that the ac-Received:Jan.17,2024 Revised:Jun.12,2024 Editor:Niu Kai curacy of text extraction approaches 95%,and the mel cepstral distortion between the recovered speech signal and the original one in the spectrum domain is less than 10.Furthermore,the experimental results show that the proposed Deep-STS system can reduce the total delay of speech communication by 85%on average compared to the G.723 coding at the transmission rate of 5.4 kbps.More importantly,the coding rate of the proposed Deep-STS system is extremely low,only 0.2 kbps for continuous speech communication.It is worth noting that the Deep-STS with lower coding rate can support the low-zero-power speech communication,unveiling a new era in ultra-efficient coded communications.
基金Project supported by Youth Project of Science and Technology Research Program of Chongqing Education Commission of China (Grant No. KJQN202404522)。
文摘Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubuleattachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data,we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.
文摘To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.The methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface sources.To address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration methods.These methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically evaluated.Finally,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface source.In situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.
基金supported by the Anhui Provincial Natural Science Foundation(2408085QA031)the third author's work was supported by the National Natural Science Foundation of China(12001033).
文摘This paper studies the global existence and large-time behaviors of weak solutions to the kinetic particle model coupled with the incompressible Navier-Stokes equations in IR3.First,we obtain the global weak solution using the characteristic and energy methods.Then,under the small assumption of the mass of the particle,we show that the solutions decay at the algebraic time-decay rate.Finally,it is also proved that the above rate is optimal.It should be remarked that if the particle in the coupled system vanishes(i.e.f=O),our works coincide with the classical results by Schonbek[32](J Amer Math Soc,1991,4:423-449),which can be regarded as a generalization from a single fuid model to the two-phase fluid one.
文摘Aiming at the gas discharge problem in electric aircraft,this work studies the gas discharge characteristics at low-temperature sub-atmospheric pressure.A gas discharge shooting platform was built,and the discharge process was photographed by intensified charge-coupled device(ICCD).A two-dimensional axisymmetric model of needle-plate electrode gas discharge was established,and three sets of Helmholtz equations were used to solve the photoionization.The results show that under the same voltage,the electric field intensity in the discharge process increases first,then decreases and finally increases again.The discharge speed increases with the increase of altitude,and the electron density in the streamer decreases with the increase of altitude.The development speed of the streamer in the middle stage is higher than that in the early stage,and the speed increases more obviously with the increase of altitude.The development speed of the streamer in the later stage is lower than that in the middle stage,but with the increase of altitude,the development speed of the streamer in the later stage is higher than that in the middle stage.
基金provided by the National Natural Science Foundation of China(No.5137403)the Fundamental Research Funds for the Central Universities(No.FRF-TP-15-042A1)
文摘The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved. Taking Chengchao Iron Mine as the engineering background, the model for analyzing the instability of deep gob was established based on the mechanism of stress relief in deep mining.The energy evolution law was analyzed by introducing the local energy release rate index(LERR), and the energy criterion of the instability of surrounding rock was established based on the cusp catastrophe theory. The results show that the evolution equation of the local energy release of the surrounding rock is a quartic function with one unknown and the release rate increases gradually during the mining process.The calculation results show that the gob is stable. The LERR per unit volume of the bottom structure is relatively smaller which means that the stability is better. The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meets the characteristics of deep mining. In summary, this model could effectively calculate the stability of surrounding rock in the formation of gob. The LERR could reflect the dynamic process of energy release,transfer and dissipation and that provided an important reference for the study of the stability of deep mined out area.
基金provided by the National Natural Science Foundation of China (No.51374097)the Science Foundation General Projects of Chinese Postgraduate (No.2014M561384)Key Project of Science and Technology Research of Department of Education in Heilongjiang Province (No.12541z009)
文摘Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was adopted to monitor the failure process of coal samples. The study of the change rule of the AE numbers, energy, ‘b' value and spectrum in the micro crack propagation process of the coal samples shows that as dynamic damage time went by, AE presented high-energy counts and the accumulated counts increased during the compression phase. The AE energy and cumulative counts increased during the elastic stage. The AE blank area increased gradually and the blank lines were more and more obvious in the molding stage. The AE counts and energy showed a trend of decrease in the residual damage phase.AE ‘b' values gradually became sparse, and the large scale cracks percentage compared with micro cracks decreased and the degree of damage decreased. The AE frequency spectrum peak went from the residual damage phase to the molding phase, and finally it was nearly stable, besides the bandwidth of the main frequency is gradually narrowed. Also, the frequency peak changed from single peak frequency to bi-peak frequency and to the single peak frequency. Uniaxial compressive strength is more sensitive than the elastic modulus to dynamic damage time.
基金This work was supported by National Basic Research Program of China(973 Program)(2015CB453303)and International Science and Technology Cooperation Program of China(2013DFA31410)
文摘Enhancement release has been proven effective in natural resources recovery of Chinese shrimp Fenneropenaeus chinensis in the last several decades in China, however, to assess the effectiveness of enhancement release, we still need to develop a high-efficient and easy-operational method to replace those physical-tagging release method with labor intensive, size-and number-limited. In the present study, single(with maternal known) parentage identification using eight simple sequence repeat(SSR) markers genotype fingerprint was used to trace Chinese shrimp released in Bohai Bay in 2013. A total of 884 shrimp spawners were collected from two hatcheries in Tianjin City respectively after enhancement release of shrimp larvae in May 2013. A total of 844 shrimp samples were recaptured around the release location approximately 4 months after the shrimp larvae were released into the natural sea. Genotype data of 8 SSR loci of the 1,726 samples were used for maternal-offspring parentage identification using CEervus 3.0 software. The allele number in each locus ranged from 8 to 68 with an average value of 33.25, which produced the cumulative exclusion probability with one parent known of all these sight loci up to 99%. Among the 844 recaptured shrimp samples, 448(♂:♀=212:232, gender information was lost for 4 samples) were successfully traced to their 337 maternal parents using a logarithm of odds(LOD) > 3.0 threshold. Among these 337 maternal parents, 253 had a single offspring, 62 had two offspring, 18 had three offspring, 3 had four offspring, and 1 had five offspring. For the first time, a large number of released shrimp were identified from recapture samples, and this study showed that it is possible to trace all released Chinese shrimp without using any type of physical tag in enhancement release activities. This not only means more precise recapture ratio assessment than ever expected, but also this method demonstrates an effective method for large-scale hatchery release as well as for organisms used in hatchery enhancement which are not suitable for physical tagging.
基金financial support from National Key Research and Development Program(2017YFD0501403)National Natural Science Foundation of China(Nos.81872819)+4 种基金Natural Science Foundation of Jiangsu Province(No.BK20171390)supported by Double First-Rate construction plan of China Pharmaceutical University(CPU2018GY26)the Project of State Key Laboratory of Natural Medicines,China Pharmaceutical University(No.SKLNMZZCX201816)the National Science and Technology Major Project(2017ZX09101001)the financial support from Development Funds for Priority Academic Programs in Jiangsu Higher Education Institutions-Young Talent Program。
文摘Stimuli-triggered drug delivery systems hold vast promise in local infection treatment for the site-specific targeting and shuttling of drugs.Herein,chitosan conjugates(SPCS)installed with sialic acid(SA)and phenylboronic acid(PBA)were synthesized,of which SA served as targeting ligand for coccidium and reversible-binding bridge for PBA.The enhanced drug-loading capacity of SPCS micelles was attributed to a combination assembly from hydrophobicity-driving and reversible borate bridges.The drug-loaded SPCS micelles shared superior biostability in upper gastrointestinal tract.After reaching the lesions,the borate bridges were snipped by carbohydrates under a higher pH followed by accelerated drug release,while SA exposure on micellar surface facilitated drug cellular internalization to eliminate parasites inside.The drugmicelles revealed an enhanced anti-coccidial capacity with a higher index of 185.72 compared with commercial preparation.The dual-responsive combination of physicochemical assembly could provide an efficient strategy for the exploitation of stable,safe and flexible anti-infectious drug delivery systems.
基金supported by the Natural Science Foundation of China under Grants U19B2025,62121001,and 62001347in part by Key Research and Development Program of Shaanxi(ProgramNo.2022ZDLGY05-02)in part by Young Talent Support Program of Xi’an Association for Science and Technology(No.095920221337).
文摘The unreasonable observation arrangements in the satellite operation control center(SOCC)may result in the observation data cannot be downloaded as scheduled.Meanwhile,if the operation instructions released by the satellite telemetry tracking center(STTC)for the on-board payloads are not injected on the specific satellites in time,the corresponding satellites cannot perform the observation operations as planned.Therefore,there is an urgent need to design an integrated instruction release,and observation task planning(I-IRO-TP)scheme by efficiently collaborating the SOCC and STTC.Motivated by this fact,we design an interaction mechanism between the SOCC and the STTC,where we first formulate the I-IRO-TP problem as a constraint satisfaction problem aiming at maximizing the number of completed tasks.Furthermore,we propose an interactive imaging task planning algorithm based on the analysis of resource distribution in the STTC during the previous planning periods to preferentially select the observation arcs that not only satisfy the requirements in the observation resource allocation phase but also facilitate the arrangement of measurement and control instruction release.We conduct extensive simulations to demonstrate the effectiveness of the proposed algorithm in terms of the number of completed tasks.
基金financially supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.51925403)the Major Research Plan of National Natural Science Foundation of China(Grant No.91934302)the National Science Foundation of China(21676052,21606042)
文摘The design and manufacture of anti-scaling surface is a prospective way to prevent scaling in oil field.In this work,a novel superhydrophobic Cu^(2+)-loaded and DTPMPA-modified anodized copper oxide(S-Cu^(2+)/D-ACO)coating was fabricated by modification of 1H,1H,2H,2H-perfluorodecyltriethoxysilane.The valid storing of scale inhibitors at the coating surface and the interfacial release of Cu^(2+)ions contribute to enhancing the anti-scaling of the S-Cu^(2+)/D-ACO coating.The water contact angle of the S-Cu^(2+)/D-ACO coating is 163.03°and exhibits superhydrophobicity,which makes it difficult for CaCO_(3)to deposit at the surface of the coating.DTPMPA will steadily lurk into the inner space,and Cu^(2+)will be loaded at the interface in the form of the DTPMPA:Cu^(2+)chelate.During the deposition of CaCO_(3),the dynamic release of DTPMPA can be realized by transferring DTPMPA:Cu^(2+)to DTPMPA:Ca^(2+).Interestingly,the released Cu^(2+)hinders the active growth of CaCO_(3).After 48 h of scaling,the mass of CaCO_(3)scale at the S-Cu^(2+)/D-ACO coating surface is only 44.1%that of the anodized copper oxide coating.The excellent anti-scaling performance of the S-Cu^(2+)/D-ACO coating is determined by the synergistic effect of the DTPMPA lurking and dynamic release,as well as the Cu^(2+)inhibition at the interface of superhydrophobic coating and against CaCO_(3)deposition.This research provides a new exploration for designing and fabricating anti-scaling superhydrophobic surface for oil field development.
基金supports from National Natural Science Foundation of China (Grant No.62205117,52275429)National Key Research and Development Program of China (Grant No.2021YFF0502700)+3 种基金Young Elite Scientists Sponsorship Program by CAST (Grant No.2022QNRC001)West Light Foundation of the Chinese Academy of Sciences (Grant No.xbzg-zdsys-202206)Knowledge Innovation Program of Wuhan-Shuguang,Innovation project of Optics Valley Laboratory (Grant No.OVL2021ZD002)Hubei Provincial Natural Science Foundation of China (Grant No.2022CFB792).
文摘Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.
基金supported by the NSFC(11931013)the GXNSF(2022GXNSFDA035078)。
文摘In this paper,we study the one-dimensional motion of viscous gas near a vacuum,with the gas connecting to a vacuum state with a jump in density.The interface behavior,the pointwise decay rates of the density function and the expanding rates of the interface are obtained with the viscosity coefficientμ(ρ)=ρ^(α)for any 0<α<1;this includes the timeweighted boundedness from below and above.The smoothness of the solution is discussed.Moreover,we construct a class of self-similar classical solutions which exhibit some interesting properties,such as optimal estimates.The present paper extends the results in[Luo T,Xin Z P,Yang T.SIAM J Math Anal,2000,31(6):1175-1191]to the jump boundary conditions case with density-dependent viscosity.
基金supported by National Natural Science Foundation of China(51903113 and 52073133)China Postdoctoral Science Foundation(2022T150282)+1 种基金Lanzhou Young Science and Technology Talent Innovation Project(2023-QN-101the Program for Hongliu Excellent and Distinguished Young Scholars at Lanzhou University of Technology.
文摘The engineering of plant-based precursor for nitrogen doping has become one of the most promising strategies to enhance rate capability of hard carbon materials for sodium-ion batteries;however,the poor rate performance is mainly caused by lack of pyridine nitrogen,which often tends to escape because of high temperature in preparation process of hard carbon.In this paper,a high-rate kapok fiber-derived hard carbon is fabricated by cross-linking carboxyl group in 2,6-pyridinedicarboxylic acid with the exposed hydroxyl group on alkalized kapok with assistance of zinc chloride.Specially,a high nitrogen doping content of 4.24%is achieved,most of which are pyridine nitrogen;this is crucial for improving the defect sites and electronic conductivity of hard carbon.The optimized carbon with feature of high nitrogen content,abundant functional groups,degree of disorder,and large layer spacing exhibits high capacity of 401.7 mAh g^(−1)at a current density of 0.05 A g^(−1),and more importantly,good rate performance,for example,even at the current density of 2 A g^(−1),a specific capacity of 159.5 mAh g^(−1)can be obtained.These findings make plant-based hard carbon a promising candidate for commercial application of sodium-ion batteries,achieving high-rate performance with the enhanced pre-cross-linking interaction between plant precursors and dopants to optimize aromatization process by auxiliary pyrolysis.
基金National Natural Science Foundation of China (Grant No. 12002045)State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology (QNKT22-09) to provide fund for conducting experiments。
文摘Titanium hydride(TiH_(2)), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types of PTFE/Al/TiH_(2) reactive liners with different TiH_(2) content are prepared by the molding and sintering method. The energy release characteristics of PTFE/Al/TiH_(2) reactive jet are tested by the transient explosion energy test, and are characterized from pressure and temperature. The reaction delay time,pressure history, and temperature history of the energy release process are obtained, then the actual value of released energy and reaction efficiency of the reactive jet are calculated. The results show that the peak pressure and temperature of the PTFE/Al/TiH_(2) jet initially increase and then decrease with increasing TiH_(2) content. When the TiH_(2) content is 10%, the actual value of released energy and reaction efficiency increased by 24% and 6.4%, respectively, compared to the PTFE/Al jet. The reaction duration of the reactive material is significantly prolonged as the TiH_(2) content increased from 0% to 30%. Finally,combined with the energy release behaviors of PAT material and the dynamic deformation process of liner, the enhancement mechanism of TiH_(2) on energy release of the reactive jet is expounded.
基金supported by the National Natural Science Foundation of China(21476145)
文摘An OH^--slow-release strategy was established to controllably tune the( α-and β-) phase of nickel cobalt binary hydroxide in the presence of ammonium chloride. Ammonium chloride is added to the ionic solution to regulate the p H of the solution and slow down the release of OH^-, effectively regulating the phase, nanostructure, interlayer spacing, surface area, thickness, and the performance of binary Ni –Co hydroxide. The ion-slow-release mechanism is conducive to the formation of α-phase with larger interlayer spacing and thinner flakes rather than β-phase. Attributed to the enlarged interlayer spacing, thinner nanosheets, and more exposed active sites, the resultant α-phase hydroxides(NCNS-5.2), displayed much lower over potential of 285 mV with respect to the dense-stacked β-phase hydroxides(362 mV) for OER at 10 mA/cm^2. It also exhibited high specific capacitance of 1474.2 F/g, when tested at 0.5 A/g within a voltage range of 0–0.45 Vvs. Hg/Hg O. This composite was also stable for water oxidation reaction and supercapacitor. The proof-of-concept of using controlled-release agent may provide suggestive insights for the material innovation and a variety of applications.
基金This work was supported by the Shanghai Municipal Science and Technology Major Project(No.2017SHZDZX02)the National Natural Science Foundation of China(No.12005282)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2021283)the Shanghai Pilot Program for Basic Research—Chinese Academy of Science,Shanghai Branch(JCYJSHFY-2021-010).
文摘The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 MHz.Kicker magnets are key components that distribute electron bunches into three different undulator lines in a bunch-by-bunch mode.The kicker field width must be less than the time interval between bunches.A lumpedinductance kicker prototype was developed using a vacuum chamber with a single-turn coil.The full magnetic field strength was 0.005 T.This paper presents the requirements,design considerations,design parameters,magnetic field calculations,and measurements of the kicker magnets.The relevant experimental results are also presented.The pulse width of the magnetic field was approximately 600 ns,and the maximum operation repetition rate was 1 MHz.The developed kicker satisfies the requirements for the SHINE project.Finally,numerous recommendations for the future optimization of kicker magnets are provided.
