In paper[Chin.Phys.B 32070308(2023)],Xing et al.proposed a semi-quantum secret sharing protocol by using single particles.We study the security of the proposed protocol and find that it is not secure,that is,the three...In paper[Chin.Phys.B 32070308(2023)],Xing et al.proposed a semi-quantum secret sharing protocol by using single particles.We study the security of the proposed protocol and find that it is not secure,that is,the three dishonest agents,Bob,Charlie and Emily can collude to obtain Alice's secret without the help of David.展开更多
Lithium ion batteries are complicated distributed parameter systems that can be described preferably by partial differential equations and a field theory. To reduce the solution difficulty and the calculation amount, ...Lithium ion batteries are complicated distributed parameter systems that can be described preferably by partial differential equations and a field theory. To reduce the solution difficulty and the calculation amount, if a distributed parameter system is described by ordinary differential equations (ODE) during the analysis and the design of distributed parameter system, the reliability of the system description will be reduced, and the systemic errors will be introduced. Studies on working condition real-time monitoring can improve the security because the rechargeable LIBs are widely used in many electronic systems and electromechanical equipment. Single particle model (SPM) is the simplification of LIB under some approximations, and can estimate the working parameters of a LIB at the faster simulation speed. A LIB modelling algorithm based on PDEs and SPM is proposed to monitor the working condition of LIBs in real time. Although the lithium ion concentration is an unmeasurable distributed parameter in the anode of LIB, the working condition monitoring model can track the real time lithium ion concentration in the anode of LIB, and calculate the residual which is the difference between the ideal data and the measured data. A fault alarm can be triggered when the residual is beyond the preset threshold. A simulation example verifies that the effectiveness and the accuracy of the working condition real-time monitoring model of LIB based on PDEs and SPM.展开更多
A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction ang...A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction angle of screen on single particle kinematics were predicted.Properties such as the average velocity and the average throw height were studied.The results show that the amplitude and the angle of vibration have a great effect on particle average velocity and average height.The vibration frequency and the screen-deck inclination angle appear to have little influence on these responses.For materials that are difficult to screen the vibration frequency and amplitude,the screen-deck inclination angle and the vibration angle should be set to 14 Hz,6.6 mm,6° and 40°,respectively,to obtain optimal particle kinematics.A screening process can be simulated reliably by means of a virtual experiment and these results provide references for both screening theory research and sieving practice.展开更多
A reliable method for detecting nanoparticles is necessary for the wide application of nanomaterials. Single particle-inductively coupled plasma mass spectrometry(SP-ICP-MS) was investigated to detect the size of gold...A reliable method for detecting nanoparticles is necessary for the wide application of nanomaterials. Single particle-inductively coupled plasma mass spectrometry(SP-ICP-MS) was investigated to detect the size of gold nanoparticles(Au NPs) in this work. Discrimination of particle signal and iterative algorithm were used to calculate the baseline of particle signal. Influence of dwell time was discussed and 3 ms was selected as dwell time for size detection. Different Au NPs standards(30, 60, 80 and 100 nm) and mixed samples(60 and 100 nm) were determined by SP-ICP-MS and the accuracy was confirmed with reference values. The particle size detection limit was 19 nm in ultrapure water(UP water) and 31 nm in 0.1 μg/L Au^(3+) solution. Stability of Au NPs in ultrapure water and natural water samples was investigated by detecting size variation of AuN Ps. The result shows that Au NPs are stable in aqueous environment for 6 d but degraded after 30 d.展开更多
Semi-quantum secret sharing(SQSS)is a branch of quantum cryptography which only requires the dealer to have quantum capabilities,reducing the difficulty of protocol implementation.However,the efficiency of the SQSS pr...Semi-quantum secret sharing(SQSS)is a branch of quantum cryptography which only requires the dealer to have quantum capabilities,reducing the difficulty of protocol implementation.However,the efficiency of the SQSS protocol still needs to be further studied.In this paper,we propose a semi-quantum secret sharing protocol,whose efficiency can approach 100%as the length of message increases.The protocol is based on single particles to reduce the difficulty of resource preparation.Particle reordering,a simple but effective operation,is used in the protocol to improve efficiency and ensure security.Furthermore,our protocol can share specific secrets while most SQSS protocols could not.We also prove that the protocol is secure against common attacks.展开更多
Single particle microbeam (SPM) is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powe...Single particle microbeam (SPM) is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism. This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.展开更多
The wave-particle duality of a single particle with an n-dimensional internal degree of freedom is re-examined theo- retically in a Mach-Zehnder interferometer. The famous duality relation D2 + V2 〈 1 is always vali...The wave-particle duality of a single particle with an n-dimensional internal degree of freedom is re-examined theo- retically in a Mach-Zehnder interferometer. The famous duality relation D2 + V2 〈 1 is always valid in this situation, where D is the distinguishability and V is the visibility. However, the sum of the particle information and the wave information, D2 V2, can be smaller than one for the input of a pure state if this initial pure state includes the internal degree of freedom of the particle, while the quantity D2~ V2 is always equal to one when the internal degree of freedom of the particle is excluded.展开更多
Fluorescence recovery after photobleaching(FRAP)and single particle tracking(SPT)techni-ques determine the diffusion coefficient from average diffusive motion of high-concentration molecules and from trajectories of l...Fluorescence recovery after photobleaching(FRAP)and single particle tracking(SPT)techni-ques determine the diffusion coefficient from average diffusive motion of high-concentration molecules and from trajectories of low-concentration single molecules,respectively.Lateral dif-fusion coefficients measured by FRAP and SPT techniques for the same biomolecule on cell membrane have exhibited inconsistent values across laboratories and platforms with larger dif-fusion coefficient determined by FRAP,but the sources of the inconsistency have not been investigated thoroughly.Here,we designed an image-based FRAP-SPT system and made a direct comparison between FRAP and SPT for diffusion coefficient of submicron particles with known theoretical values derived from Stokes-Einstein equation in aqueous solution.The combined iFRAP-SPT technique allowed us to measure the diffusion coefficient of the same fluorescent particle by utilizing both techniques in a single platform and to scrutinize inherent errors and artifacts of FRAP.Our results reveal that diffusion coefficient overestimated by FRAP is caused by inaccurate estimation of the bleaching spot size and can be corrected by simple image analysis.Our iFRAP-SPT technique can be potentially used for not only cellular membrane dynamics but also for quantitative analysis of the spatiotemporal distribution of the solutes in small scale analytical devices.展开更多
Biology is a challenging and complicated mess. Understanding this challenging complexity is the realm of the biological sciences: Trying to make sense of the massive, messy data in terms of discovering patterns and re...Biology is a challenging and complicated mess. Understanding this challenging complexity is the realm of the biological sciences: Trying to make sense of the massive, messy data in terms of discovering patterns and revealing its underlying general rules. Among the most powerful mathematical tools for organizing and helping to structure complex, heterogeneous and noisy data are the tools provided by multivariate statistical analysis (MSA) approaches. These eigenvector/eigenvalue data-compression approaches were first introduced to electron microscopy (EM) in 1980 to help sort out different views of macromolecules in a micrograph. After 35 years of continuous use and developments, new MSA applications are still being proposed regularly. The speed of computing has increased dramatically in the decades since their first use in electron microscopy. However, we have also seen a possibly even more rapid increase in the size and complexity of the EM data sets to be studied. MSA computations had thus become a very serious bottleneck limiting its general use. The parallelization of our programs—speeding up the process by orders of magnitude—has opened whole new avenues of research. The speed of the automatic classification in the compressed eigenvector space had also become a bottleneck which needed to be removed. In this paper we explain the basic principles of multivariate statistical eigenvector-eigenvalue data compression;we provide practical tips and application examples for those working in structural biology, and we provide the more experienced researcher in this and other fields with the formulas associated with these powerful MSA approaches.展开更多
The addition of superelastic NiTi to electroless Ni-P coating has been found to toughen the otherwise brittle coatings in static loading conditions, though its effect on erosion behaviour has not yet been explored. In...The addition of superelastic NiTi to electroless Ni-P coating has been found to toughen the otherwise brittle coatings in static loading conditions, though its effect on erosion behaviour has not yet been explored. In the present study, spherical WC-Co erodent particles were used in single particle impact testing of Ni-P-nano-NiTi composite coatings on API X100 steel substrates at two average velocities—35 m/s and 52 m/s. Erosion tests were performed at impact angles of 30°, 45°, 60°, and 90°. The effect of NiTi concentration in the coating was also examined. Through examination of the impact craters and material response at various impact conditions, it was found that the presence of superelastic NiTi in the brittle Ni-P matrix hindered the propagation of cracks and provided a barrier to crack growth. The following toughening mechanisms were identified: crack bridging and deflection, micro-cracking, and transformation toughening.展开更多
Dielectrophoretic(DEP) force is significant in manipulating tiny objects in micro/nano scale. To study the effect of electric interaction force on particle manipulation, a microstructure consisting of a pair of strip ...Dielectrophoretic(DEP) force is significant in manipulating tiny objects in micro/nano scale. To study the effect of electric interaction force on particle manipulation, a microstructure consisting of a pair of strip electrodes and a sudden contraction micro-channel was constructed. Besides DEP force and hydrodynamic force acting on single particle, the numerical model also involved electric interaction force and force moment on two particles. The analyses revealed that the particle-particle interaction force was in the same order as that of DEP force on single trapped particle. The interaction force resulted in trapping single particle failure under continuous DEP force.Thus, pulsed DEP force, turning on/off DEP force at a given time interval, was suggested. During the "off" period,the velocity difference of the two particles located at sudden contraction micro-channel enlarged the gap between them and further weakened the particle-particle interaction. By a proof-of-concept experiment, both the trapping behavior of single particle and that of two particles were in good agreement with the model.With carefully controlled parameters, the reliable function of retaining single particle was realized by pulsed DEP.展开更多
A droplet carrying particle is desolvation, vaporization, ionization, and diffusion in an inductively coupled plasma (ICP) to form a cloud of ions. It then is detected as a mass-spectrum peak of individual particle. T...A droplet carrying particle is desolvation, vaporization, ionization, and diffusion in an inductively coupled plasma (ICP) to form a cloud of ions. It then is detected as a mass-spectrum peak of individual particle. The diameter of the particle is derived from its mass, which is calibrated using the peak area. This is the basic principle of measuring single particles using inductively coupled plasma mass spectrometry (ICP-MS). In this paper, a mathematical model describing single particles in plasma is investigated. This makes it possible to investigate the process and contributing factors of single particles measurement by ICP-MS. A series of processes are investigated, which include increasing the droplet temperature to the boiling point, desolvation of the droplets, increasing the particle temperature to the melting point, the particles are melted from a solid to the liquid, increasing the particle temperature to the boiling point, and particle vaporization. The simulation shows that both the atomic (ion) diffusion in the plasma and the incomplete vaporization of the particles are two important factors that limit the signal intensity of the particle’s mass spectrum. The experiment reveals that ICP-MS is very linear for Ag nanoparticles below 100 nm and SiO2 particles below 1000 nm. Both the simulation and experiment reveal the measurement deviation for large particles and that an increase of sampling depth can extend the diffusion time and cause signal suppression. The model can be used to study the mechanisms of monodispersed droplet or single-particle mass spectrometry, analyze the contributing parameters for single particle measurements by ICP-MS and provide a theoretical base for the optimization of single particle measurements in the practical application, such as nanoparticle devices, magnetic materials, biomedical materials additives and consumer products.展开更多
Oxygenated organic molecules(OOMs)play an important role in the formation of secondary organic aerosols(SOAs),but the mixing states of OOMs are still unclear.This study investigates the mixing states of OOM-containing...Oxygenated organic molecules(OOMs)play an important role in the formation of secondary organic aerosols(SOAs),but the mixing states of OOMs are still unclear.This study investigates the mixing states of OOM-containing single particles from the measurements taken using a single particle aerosol mass spectrometer in Guangzhou,China in 2022.Generally,the particle counts of OOM particles and the mass concentration of secondary organic carbon(SOC)exhibited similar temporal trends throughout the entire year.The OOM particles were consistently enriched in secondary ions,including ^(16)O^(−),^(26)CN^(−),^(46)NO_(2)^(−),^(62)NO_(3)^(−),and ^(97)HSO_(4)^(−).In contrast,the number fractions and diurnal patterns of OOM particles among the total detected particles showed similar distributions in August and October;however,the SOC ratios in fine particulate matter were quite different,suggesting that there were different mixing states of single-particle oxygenated organics.In addition,further classification results indicated that the OOM particles were more aged in October than August,even though the SOC ratios were higher in August.Furthermore,the distribution of hydrocarbon fragments exhibited a notable decrease from January to October,emphasizing the more aged state of the organics in October.In addition,the sharp increase in elemental carbon(EC)-OOM particles in the afternoon in October suggests the potential role of EC in the aging process of organics.Overall,in contrast to the bulk analysis of SOC mass concentration,the mixing states of the OOM particles provide insights into the formation process of SOAs in field studies.展开更多
Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON ...Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON compounds are still unclear.This paper reports on the mixing state of ON-containing particles based on measurements obtained using a highperformance single particle aerosol mass spectrometer in January 2020 in Guangzhou.The ON-containing particles accounted for 21% of the total detected single particles,and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day.The prominent increase in the content of ON-containing particles with the enhancement of NO_xmainly occurred at night,and accompanied by high relative humidity and nitrate,which were associated with heterogeneous reactions between organics and gaseous NO_(x)and/or NO_(3)radical.The synchronous decreases in ON-containing particles and the mass absorption coefficient of water-soluble extracts at 365 nm in the afternoon may be associated with photo-bleaching of the ON species in the particles.In addition,the positive matrix factorization analysis found five factors dominated the formation processes of ON particles,and the nitrate factor(33%)mainly contributed to the production of ON particles at night.The results of this study provide unique insights into the mixing states and secondary formation processes of the ON-containing particles.展开更多
Acid phosphatase(ACP)is a ubiquitous phosphatase in living organisms.The abnormal variation of ACP is related to various diseases.Herein,we propose a colorimetric method based on CeO_(2)-modified gold core shell nanop...Acid phosphatase(ACP)is a ubiquitous phosphatase in living organisms.The abnormal variation of ACP is related to various diseases.Herein,we propose a colorimetric method based on CeO_(2)-modified gold core shell nanoparticles(Au@CeO_(2)NPs)to analyze ACP activity with high sensitivity and specificity.In this design,2-phospho-L-ascorbic acid trisodium salt(AAP)is dephosphorylated by ACP and produces reductive ascorbic acid(AA),which makes the CeO_(2)shell decomposition.A remarkable blue shift of localized surface plasmon resonance peak(LSPR,from yellow to green)along with the scattering intensity ratio changes from individual Au@CeO_(2)NPs are observed.ACP activity can be quantified by calculating the ratio changes of individual Au@CeO_(2)NPs.This assay reveals limit of detection(LOD)of 0.044 mU/mL and the linear range of 0.05–5.0 mU/mL,which are much lower than most of spectroscopic measurements in bulk solution.Furthermore,the recovery measurements in real samples are satisfactory and the capacity for practical application is demonstrated.As a consequence,Au@CeO_(2)NPs used in this assay will find new applications for the ultrasensitive detection of enzyme activity.展开更多
The Tibetan Plateau,known as the“Third Pole”,is currently in a state of perturbation caused by intensified human activity.In this study,56 samples were obtained at the five sampling sites in typical area of Lhasa ci...The Tibetan Plateau,known as the“Third Pole”,is currently in a state of perturbation caused by intensified human activity.In this study,56 samples were obtained at the five sampling sites in typical area of Lhasa city and their physical and chemical properties were investigated by TEM/EDS,STXM,and NEXAFS spectroscopy.After careful examination of 3387single particles,the results showed that Fe should be one of the most frequent metal elements.The Fe-containing single particles in irregular shape and micrometer size was about7.8%and might be mainly from local sources.Meanwhile,the Fe was located on the subsurface of single particles and might be existed in the form of iron oxide.Interestingly,the core-shell structure of iron-containing particles were about 38.8%and might be present as single-,dual-or triple-core shell structure and multi-core shell structure with the Fe/Si ratios of 17.5,10.5,2.9 and 1.2,respectively.Meanwhile,iron and manganese were found to coexist with identical distributions in the single particles,which might induce a synergistic effect between iron and manganese in catalytic oxidation.Finally,the solid spherical structure of Fe-containing particles without an external layer were about 53.4%.The elements of Fe and Mn were co-existed,and might be presented as iron oxide-manganese oxide-silica composite.Moreover,the ferrous and ferric forms of iron might be co-existed.Such information can be valuable in expanding our understanding of Fe-containing particles in the Tibetan Plateau atmosphere.展开更多
Colloidal quantum dots(QDs),the building blocks of modern displays and optoelectronic devices,have reached the highest level of size and shape control,and stability during the last 30 years.However,full utilization of...Colloidal quantum dots(QDs),the building blocks of modern displays and optoelectronic devices,have reached the highest level of size and shape control,and stability during the last 30 years.However,full utilization of their potential requires integration or assembly of more than one nanocrystal as in the case of coupled quantum dots molecules(CQDM),where two core–shell QDs are fused to form two emission centers in close proximity.These CQDMs were recently shown to switch color under an applied electric field at room temperature.Here we use cryogenic single particle spectroscopy of single CQDMs under an electric field to show that various mechanisms can contribute to the spectrum change under an applied electric field at cryogenic temperatures.The first mechanism is the control of the delocalized electron wave function when the electric field is applied along the dimer axis.The electric field bends the conduction band and forces the electron wave function to localize in one of the QDs yielding preferential emission of that particular center.In addition,we found that QDs and CQDMs could become sensitive to surface traps under an electric field.In the case of CQDMs,that can result in decreasing the intensity of one of the QDs while increasing the other QD’s intensity.Moreover,we show that there are surface charges which screen the applied electric field in some of the QDs.This as well can result in electric field-induced color-tuning of CQDMs.Understanding the underlying mechanisms responsible for spectral shifts under applied electric fields is critical for the development of color-tunable devices utilizing CQDMs,including efficient displays and single photon sources.展开更多
Modulating electronic structures of single-atom metal cocatalysts is vital for highly active photoreduction of CO_(2),and it's especially challenging to develop a facile method to modify the dispersion of atomical...Modulating electronic structures of single-atom metal cocatalysts is vital for highly active photoreduction of CO_(2),and it's especially challenging to develop a facile method to modify the dispersion of atomical photocatalytic sites.We herein report an ion-loading pyrolysis route to in-situ anchor Pd single atoms as well as twinned Pd nanoparticles on ultra-thin graphitic carbon nitride nanosheets(PdTP/Pd_(SA)-CN)for high-efficiency photoreduction of CO_(2).The anchored Pd twinned nanoparticles donate electrons to adjacent single Pd–N_(4) sites through the carbon nitride networks,and the optimized PdTP/Pd_(SA)-CN photocatalyst exhibits a CO evolution rate up to 46.5μmol g^(-1) h^(-1) with nearly 100%selectivity.As revealed by spectroscopic and theoretical analyses,the superior photocatalytic activity is attributed to the lowered desorption barrier of carbonyl species at electron-enriched Pd single atoms,together with the improved efficiencies of light-harvesting and charge separation/transport.This work has demonstrated the engineering of the electron density of single active sites with twinned metal nanoparticles assisted by strong electronic interaction with the support of the atomic metal,and unveiled the underlying mechanism for expedited photocatalytic efficiency.展开更多
Combining single atoms with clusters or nanoparticles is an emerging tactic to design efficient electrocatalysts.Both synergy effect and high atomic utilization of active sites in the composite catalysts result in enh...Combining single atoms with clusters or nanoparticles is an emerging tactic to design efficient electrocatalysts.Both synergy effect and high atomic utilization of active sites in the composite catalysts result in enhanced electrocatalytic performance,simultaneously provide a radical analysis of the interrelationship between structure and activity.In this review,the recent advances of single-atomic site catalysts coupled with clusters or nanoparticles are emphasized.Firstly,the synthetic strategies,characterization,dynamics and types of single atoms coupled with clusters/nanoparticles are introduced,and then the key factors controlling the structure of the composite catalysts are discussed.Next,several clean energy catalytic reactions performed over the synergistic composite catalysts are illustrated.Eventually,the encountering challenges and recommendations for the future advancement of synergistic structure in energy-transformation electrocatalysis are outlined.展开更多
Visual object-tracking is a fundamental task applied in many applications of computer vision. Particle filter is one of the techniques which has been widely used in object tracking. Due to the virtue of extendability ...Visual object-tracking is a fundamental task applied in many applications of computer vision. Particle filter is one of the techniques which has been widely used in object tracking. Due to the virtue of extendability and flexibility on both linear and non-linear environments, various particle filter-based trackers have been proposed in the literature. However, the conventional approach cannot handle very large videos efficiently in the current data intensive information age. In this work, a parallelized particle filter is provided in a distributed framework provided by the Hadoop/Map-Reduce infrastructure to tackle object-tracking tasks. The experiments indicate that the proposed algorithm has a better convergence and accuracy as compared to the traditional particle filter. The computational power and the scalability of the proposed particle filter in single object tracking have been enhanced as well.展开更多
基金Project supported by the Offline Course Program of“Experiment of College Physics”in the 2022-year Anhui Provincial Quality Engineering Program (Grant No.2022xxkc134)the Program for Academic Leader Reserve Candidates in Tongling University (Grant Nos.2020tlxyxs43 and 2014tlxyxs30)+1 种基金the Talent Scientific Research Foundation of Tongling University (Grant No.2015tlxyrc01)the 2014 year Program for Excellent Youth Talents in University of Anhui Province。
文摘In paper[Chin.Phys.B 32070308(2023)],Xing et al.proposed a semi-quantum secret sharing protocol by using single particles.We study the security of the proposed protocol and find that it is not secure,that is,the three dishonest agents,Bob,Charlie and Emily can collude to obtain Alice's secret without the help of David.
文摘Lithium ion batteries are complicated distributed parameter systems that can be described preferably by partial differential equations and a field theory. To reduce the solution difficulty and the calculation amount, if a distributed parameter system is described by ordinary differential equations (ODE) during the analysis and the design of distributed parameter system, the reliability of the system description will be reduced, and the systemic errors will be introduced. Studies on working condition real-time monitoring can improve the security because the rechargeable LIBs are widely used in many electronic systems and electromechanical equipment. Single particle model (SPM) is the simplification of LIB under some approximations, and can estimate the working parameters of a LIB at the faster simulation speed. A LIB modelling algorithm based on PDEs and SPM is proposed to monitor the working condition of LIBs in real time. Although the lithium ion concentration is an unmeasurable distributed parameter in the anode of LIB, the working condition monitoring model can track the real time lithium ion concentration in the anode of LIB, and calculate the residual which is the difference between the ideal data and the measured data. A fault alarm can be triggered when the residual is beyond the preset threshold. A simulation example verifies that the effectiveness and the accuracy of the working condition real-time monitoring model of LIB based on PDEs and SPM.
基金support from the Innovative Research Groups of the National Natural Science Foundation of China (No.50921002)the National Natural Science Foundation of China (Nos.50574091 and 50774084)+1 种基金the "333 Project" Foundation of Jiangsu Provincethe Key Laboratory of Coal Processing & Efficient Utilization,Ministry of Education Foundation (No.CPEUKF 08-02) for this work
文摘A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction angle of screen on single particle kinematics were predicted.Properties such as the average velocity and the average throw height were studied.The results show that the amplitude and the angle of vibration have a great effect on particle average velocity and average height.The vibration frequency and the screen-deck inclination angle appear to have little influence on these responses.For materials that are difficult to screen the vibration frequency and amplitude,the screen-deck inclination angle and the vibration angle should be set to 14 Hz,6.6 mm,6° and 40°,respectively,to obtain optimal particle kinematics.A screening process can be simulated reliably by means of a virtual experiment and these results provide references for both screening theory research and sieving practice.
基金Projects(21407182,21277175)supported by the National Natural Science Foundation of ChinaProject(20120162110019)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘A reliable method for detecting nanoparticles is necessary for the wide application of nanomaterials. Single particle-inductively coupled plasma mass spectrometry(SP-ICP-MS) was investigated to detect the size of gold nanoparticles(Au NPs) in this work. Discrimination of particle signal and iterative algorithm were used to calculate the baseline of particle signal. Influence of dwell time was discussed and 3 ms was selected as dwell time for size detection. Different Au NPs standards(30, 60, 80 and 100 nm) and mixed samples(60 and 100 nm) were determined by SP-ICP-MS and the accuracy was confirmed with reference values. The particle size detection limit was 19 nm in ultrapure water(UP water) and 31 nm in 0.1 μg/L Au^(3+) solution. Stability of Au NPs in ultrapure water and natural water samples was investigated by detecting size variation of AuN Ps. The result shows that Au NPs are stable in aqueous environment for 6 d but degraded after 30 d.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB1805405)the 111 Project(Grant No.B21049),the National Natural Science Foundation of China(Grant No.62272051)+1 种基金the Foundation of Guizhou Provincial Key Laboratory of Public Big Data(Grant No.2019BDKFJJ014)the Fundamental Research Funds for the Central Universities of China(Grant Nos.2019XD-A02 and 2020RC38).
文摘Semi-quantum secret sharing(SQSS)is a branch of quantum cryptography which only requires the dealer to have quantum capabilities,reducing the difficulty of protocol implementation.However,the efficiency of the SQSS protocol still needs to be further studied.In this paper,we propose a semi-quantum secret sharing protocol,whose efficiency can approach 100%as the length of message increases.The protocol is based on single particles to reduce the difficulty of resource preparation.Particle reordering,a simple but effective operation,is used in the protocol to improve efficiency and ensure security.Furthermore,our protocol can share specific secrets while most SQSS protocols could not.We also prove that the protocol is secure against common attacks.
基金the National Science Foundation for Distinguished Young Scholars of China(No.10225526)the Knowledge Innovation Program of the Chinese Academy Sciences(No.KSCX2-SW-324)the Foundation for University Key Teachers by the Ministry of Education of China(No.2005jq1135)
文摘Single particle microbeam (SPM) is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism. This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB921603)the National Natural Science Foundation of China(Grant Nos.11125418 and 11364022)
文摘The wave-particle duality of a single particle with an n-dimensional internal degree of freedom is re-examined theo- retically in a Mach-Zehnder interferometer. The famous duality relation D2 + V2 〈 1 is always valid in this situation, where D is the distinguishability and V is the visibility. However, the sum of the particle information and the wave information, D2 V2, can be smaller than one for the input of a pure state if this initial pure state includes the internal degree of freedom of the particle, while the quantity D2~ V2 is always equal to one when the internal degree of freedom of the particle is excluded.
基金This work was supported by grants from the National Research Foundation(NRF)(NRF2019R1A2C2088973)funded by the Ministry of Educationthe Korea Evaluation Institute of Industrial Technology(KEIT)(20011377)funded by the Ministry of Trade,Industry&Energy,Republic of Korea.
文摘Fluorescence recovery after photobleaching(FRAP)and single particle tracking(SPT)techni-ques determine the diffusion coefficient from average diffusive motion of high-concentration molecules and from trajectories of low-concentration single molecules,respectively.Lateral dif-fusion coefficients measured by FRAP and SPT techniques for the same biomolecule on cell membrane have exhibited inconsistent values across laboratories and platforms with larger dif-fusion coefficient determined by FRAP,but the sources of the inconsistency have not been investigated thoroughly.Here,we designed an image-based FRAP-SPT system and made a direct comparison between FRAP and SPT for diffusion coefficient of submicron particles with known theoretical values derived from Stokes-Einstein equation in aqueous solution.The combined iFRAP-SPT technique allowed us to measure the diffusion coefficient of the same fluorescent particle by utilizing both techniques in a single platform and to scrutinize inherent errors and artifacts of FRAP.Our results reveal that diffusion coefficient overestimated by FRAP is caused by inaccurate estimation of the bleaching spot size and can be corrected by simple image analysis.Our iFRAP-SPT technique can be potentially used for not only cellular membrane dynamics but also for quantitative analysis of the spatiotemporal distribution of the solutes in small scale analytical devices.
文摘Biology is a challenging and complicated mess. Understanding this challenging complexity is the realm of the biological sciences: Trying to make sense of the massive, messy data in terms of discovering patterns and revealing its underlying general rules. Among the most powerful mathematical tools for organizing and helping to structure complex, heterogeneous and noisy data are the tools provided by multivariate statistical analysis (MSA) approaches. These eigenvector/eigenvalue data-compression approaches were first introduced to electron microscopy (EM) in 1980 to help sort out different views of macromolecules in a micrograph. After 35 years of continuous use and developments, new MSA applications are still being proposed regularly. The speed of computing has increased dramatically in the decades since their first use in electron microscopy. However, we have also seen a possibly even more rapid increase in the size and complexity of the EM data sets to be studied. MSA computations had thus become a very serious bottleneck limiting its general use. The parallelization of our programs—speeding up the process by orders of magnitude—has opened whole new avenues of research. The speed of the automatic classification in the compressed eigenvector space had also become a bottleneck which needed to be removed. In this paper we explain the basic principles of multivariate statistical eigenvector-eigenvalue data compression;we provide practical tips and application examples for those working in structural biology, and we provide the more experienced researcher in this and other fields with the formulas associated with these powerful MSA approaches.
文摘The addition of superelastic NiTi to electroless Ni-P coating has been found to toughen the otherwise brittle coatings in static loading conditions, though its effect on erosion behaviour has not yet been explored. In the present study, spherical WC-Co erodent particles were used in single particle impact testing of Ni-P-nano-NiTi composite coatings on API X100 steel substrates at two average velocities—35 m/s and 52 m/s. Erosion tests were performed at impact angles of 30°, 45°, 60°, and 90°. The effect of NiTi concentration in the coating was also examined. Through examination of the impact craters and material response at various impact conditions, it was found that the presence of superelastic NiTi in the brittle Ni-P matrix hindered the propagation of cracks and provided a barrier to crack growth. The following toughening mechanisms were identified: crack bridging and deflection, micro-cracking, and transformation toughening.
基金the financial support from the National Natural Science Foundation of China (11602187)the Shaanxi Provincial Natural Science Foundation (2018JM1029)
文摘Dielectrophoretic(DEP) force is significant in manipulating tiny objects in micro/nano scale. To study the effect of electric interaction force on particle manipulation, a microstructure consisting of a pair of strip electrodes and a sudden contraction micro-channel was constructed. Besides DEP force and hydrodynamic force acting on single particle, the numerical model also involved electric interaction force and force moment on two particles. The analyses revealed that the particle-particle interaction force was in the same order as that of DEP force on single trapped particle. The interaction force resulted in trapping single particle failure under continuous DEP force.Thus, pulsed DEP force, turning on/off DEP force at a given time interval, was suggested. During the "off" period,the velocity difference of the two particles located at sudden contraction micro-channel enlarged the gap between them and further weakened the particle-particle interaction. By a proof-of-concept experiment, both the trapping behavior of single particle and that of two particles were in good agreement with the model.With carefully controlled parameters, the reliable function of retaining single particle was realized by pulsed DEP.
文摘A droplet carrying particle is desolvation, vaporization, ionization, and diffusion in an inductively coupled plasma (ICP) to form a cloud of ions. It then is detected as a mass-spectrum peak of individual particle. The diameter of the particle is derived from its mass, which is calibrated using the peak area. This is the basic principle of measuring single particles using inductively coupled plasma mass spectrometry (ICP-MS). In this paper, a mathematical model describing single particles in plasma is investigated. This makes it possible to investigate the process and contributing factors of single particles measurement by ICP-MS. A series of processes are investigated, which include increasing the droplet temperature to the boiling point, desolvation of the droplets, increasing the particle temperature to the melting point, the particles are melted from a solid to the liquid, increasing the particle temperature to the boiling point, and particle vaporization. The simulation shows that both the atomic (ion) diffusion in the plasma and the incomplete vaporization of the particles are two important factors that limit the signal intensity of the particle’s mass spectrum. The experiment reveals that ICP-MS is very linear for Ag nanoparticles below 100 nm and SiO2 particles below 1000 nm. Both the simulation and experiment reveal the measurement deviation for large particles and that an increase of sampling depth can extend the diffusion time and cause signal suppression. The model can be used to study the mechanisms of monodispersed droplet or single-particle mass spectrometry, analyze the contributing parameters for single particle measurements by ICP-MS and provide a theoretical base for the optimization of single particle measurements in the practical application, such as nanoparticle devices, magnetic materials, biomedical materials additives and consumer products.
基金supported by the National Natural Science Foundation of China(Grant Nos.41827804 and 41805093)the Natural Science Foundation of Guangdong Province(China)(No.2021A1515011206)+1 种基金the State Key Laboratory of Marine Resource Utilization in the South China Sea,Hainan University(China)(No.MRUKF2023009)the State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,CAS(No.SKLLQG2218).
文摘Oxygenated organic molecules(OOMs)play an important role in the formation of secondary organic aerosols(SOAs),but the mixing states of OOMs are still unclear.This study investigates the mixing states of OOM-containing single particles from the measurements taken using a single particle aerosol mass spectrometer in Guangzhou,China in 2022.Generally,the particle counts of OOM particles and the mass concentration of secondary organic carbon(SOC)exhibited similar temporal trends throughout the entire year.The OOM particles were consistently enriched in secondary ions,including ^(16)O^(−),^(26)CN^(−),^(46)NO_(2)^(−),^(62)NO_(3)^(−),and ^(97)HSO_(4)^(−).In contrast,the number fractions and diurnal patterns of OOM particles among the total detected particles showed similar distributions in August and October;however,the SOC ratios in fine particulate matter were quite different,suggesting that there were different mixing states of single-particle oxygenated organics.In addition,further classification results indicated that the OOM particles were more aged in October than August,even though the SOC ratios were higher in August.Furthermore,the distribution of hydrocarbon fragments exhibited a notable decrease from January to October,emphasizing the more aged state of the organics in October.In addition,the sharp increase in elemental carbon(EC)-OOM particles in the afternoon in October suggests the potential role of EC in the aging process of organics.Overall,in contrast to the bulk analysis of SOC mass concentration,the mixing states of the OOM particles provide insights into the formation process of SOAs in field studies.
基金supported by the Key-Area Research and Development Program of Guangdong Province(No.2020B1111360001)the National Natural Science Foundation of China(Nos.41805093 and 41827804)+7 种基金the Natural Science Foundation of Guangdong Province(No.2021A1515011206)the GDAS’Project of Science and Technology Development(No.2021GDASYL-20210103058)the State Key Laboratory of Organic Geochemistry(No.SKLOG202105)Guangdong Foundation for Program of Science and Technology Research(No.2020B1212060053)the State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,CAS(No.SKLLQG2218)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515012165)Scientific research special project of Pudong new district Ecological and Environmental Bureau(No.PDHJ20210008)the Shanghai Municipal Science and Technology Commission Natural Fund(No.20ZR1449700)。
文摘Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON compounds are still unclear.This paper reports on the mixing state of ON-containing particles based on measurements obtained using a highperformance single particle aerosol mass spectrometer in January 2020 in Guangzhou.The ON-containing particles accounted for 21% of the total detected single particles,and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day.The prominent increase in the content of ON-containing particles with the enhancement of NO_xmainly occurred at night,and accompanied by high relative humidity and nitrate,which were associated with heterogeneous reactions between organics and gaseous NO_(x)and/or NO_(3)radical.The synchronous decreases in ON-containing particles and the mass absorption coefficient of water-soluble extracts at 365 nm in the afternoon may be associated with photo-bleaching of the ON species in the particles.In addition,the positive matrix factorization analysis found five factors dominated the formation processes of ON particles,and the nitrate factor(33%)mainly contributed to the production of ON particles at night.The results of this study provide unique insights into the mixing states and secondary formation processes of the ON-containing particles.
基金supported by the Natural Science Foundation of Hunan Province,China(No.2022JJ40266)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University,China(No.2022A04).
文摘Acid phosphatase(ACP)is a ubiquitous phosphatase in living organisms.The abnormal variation of ACP is related to various diseases.Herein,we propose a colorimetric method based on CeO_(2)-modified gold core shell nanoparticles(Au@CeO_(2)NPs)to analyze ACP activity with high sensitivity and specificity.In this design,2-phospho-L-ascorbic acid trisodium salt(AAP)is dephosphorylated by ACP and produces reductive ascorbic acid(AA),which makes the CeO_(2)shell decomposition.A remarkable blue shift of localized surface plasmon resonance peak(LSPR,from yellow to green)along with the scattering intensity ratio changes from individual Au@CeO_(2)NPs are observed.ACP activity can be quantified by calculating the ratio changes of individual Au@CeO_(2)NPs.This assay reveals limit of detection(LOD)of 0.044 mU/mL and the linear range of 0.05–5.0 mU/mL,which are much lower than most of spectroscopic measurements in bulk solution.Furthermore,the recovery measurements in real samples are satisfactory and the capacity for practical application is demonstrated.As a consequence,Au@CeO_(2)NPs used in this assay will find new applications for the ultrasensitive detection of enzyme activity.
基金supported by the National Natural Science Foundation of China(No.21677116)the environmental risk management and control of industrial solid waste recycling process in low temperature and low pressure with anoxic environment(No.2019YFC190410304)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(Nos.2019QZKK0603,2019QZKK0605)the Central Government Supports the Phased Achievement Funding of Local University Projects(ZCKJZ[2022]No.1,[2021]No.1,[2020]No.1 and[2019]No.44)the"High level talents"training program for Postgraduates of Tibet University,2021-GSP-B016。
文摘The Tibetan Plateau,known as the“Third Pole”,is currently in a state of perturbation caused by intensified human activity.In this study,56 samples were obtained at the five sampling sites in typical area of Lhasa city and their physical and chemical properties were investigated by TEM/EDS,STXM,and NEXAFS spectroscopy.After careful examination of 3387single particles,the results showed that Fe should be one of the most frequent metal elements.The Fe-containing single particles in irregular shape and micrometer size was about7.8%and might be mainly from local sources.Meanwhile,the Fe was located on the subsurface of single particles and might be existed in the form of iron oxide.Interestingly,the core-shell structure of iron-containing particles were about 38.8%and might be present as single-,dual-or triple-core shell structure and multi-core shell structure with the Fe/Si ratios of 17.5,10.5,2.9 and 1.2,respectively.Meanwhile,iron and manganese were found to coexist with identical distributions in the single particles,which might induce a synergistic effect between iron and manganese in catalytic oxidation.Finally,the solid spherical structure of Fe-containing particles without an external layer were about 53.4%.The elements of Fe and Mn were co-existed,and might be presented as iron oxide-manganese oxide-silica composite.Moreover,the ferrous and ferric forms of iron might be co-existed.Such information can be valuable in expanding our understanding of Fe-containing particles in the Tibetan Plateau atmosphere.
基金support from the Israel Science Foundation(ISF,No.3415/21)support by the Ministry of Science and Technology&the National Foundation for Applied and Engineering Sciences and the council for higher education,Israel.U.B.thanks the Alfred&Erica Larisch memorial chair.
文摘Colloidal quantum dots(QDs),the building blocks of modern displays and optoelectronic devices,have reached the highest level of size and shape control,and stability during the last 30 years.However,full utilization of their potential requires integration or assembly of more than one nanocrystal as in the case of coupled quantum dots molecules(CQDM),where two core–shell QDs are fused to form two emission centers in close proximity.These CQDMs were recently shown to switch color under an applied electric field at room temperature.Here we use cryogenic single particle spectroscopy of single CQDMs under an electric field to show that various mechanisms can contribute to the spectrum change under an applied electric field at cryogenic temperatures.The first mechanism is the control of the delocalized electron wave function when the electric field is applied along the dimer axis.The electric field bends the conduction band and forces the electron wave function to localize in one of the QDs yielding preferential emission of that particular center.In addition,we found that QDs and CQDMs could become sensitive to surface traps under an electric field.In the case of CQDMs,that can result in decreasing the intensity of one of the QDs while increasing the other QD’s intensity.Moreover,we show that there are surface charges which screen the applied electric field in some of the QDs.This as well can result in electric field-induced color-tuning of CQDMs.Understanding the underlying mechanisms responsible for spectral shifts under applied electric fields is critical for the development of color-tunable devices utilizing CQDMs,including efficient displays and single photon sources.
基金We appreciate the financial support from the National Natural Science Foundation of China(22272150,22102145)the Major Program of Zhejiang Provincial Natural Science Foundation(LD22B030002)+3 种基金Zhejiang Provincial Ten Thousand Talent Program(2021R51009)Zhejiang Provincial Natural Science Foundation of China(LQ23B030006,LY22B030012)Shandong Provincial Natural Science Foundation of China(2020MB053)the Fundamental Research Funds for the Central Universities(DUT22RC(3)084).
文摘Modulating electronic structures of single-atom metal cocatalysts is vital for highly active photoreduction of CO_(2),and it's especially challenging to develop a facile method to modify the dispersion of atomical photocatalytic sites.We herein report an ion-loading pyrolysis route to in-situ anchor Pd single atoms as well as twinned Pd nanoparticles on ultra-thin graphitic carbon nitride nanosheets(PdTP/Pd_(SA)-CN)for high-efficiency photoreduction of CO_(2).The anchored Pd twinned nanoparticles donate electrons to adjacent single Pd–N_(4) sites through the carbon nitride networks,and the optimized PdTP/Pd_(SA)-CN photocatalyst exhibits a CO evolution rate up to 46.5μmol g^(-1) h^(-1) with nearly 100%selectivity.As revealed by spectroscopic and theoretical analyses,the superior photocatalytic activity is attributed to the lowered desorption barrier of carbonyl species at electron-enriched Pd single atoms,together with the improved efficiencies of light-harvesting and charge separation/transport.This work has demonstrated the engineering of the electron density of single active sites with twinned metal nanoparticles assisted by strong electronic interaction with the support of the atomic metal,and unveiled the underlying mechanism for expedited photocatalytic efficiency.
基金financially supported by the National Natural Science Foundation of China(22279036)the Innovation Talent Recruitment Base of New Energy Chemistry Device(B21003)the Fundamental Research Funds for the Central Universities(no.2019kfyRCPY100).
文摘Combining single atoms with clusters or nanoparticles is an emerging tactic to design efficient electrocatalysts.Both synergy effect and high atomic utilization of active sites in the composite catalysts result in enhanced electrocatalytic performance,simultaneously provide a radical analysis of the interrelationship between structure and activity.In this review,the recent advances of single-atomic site catalysts coupled with clusters or nanoparticles are emphasized.Firstly,the synthetic strategies,characterization,dynamics and types of single atoms coupled with clusters/nanoparticles are introduced,and then the key factors controlling the structure of the composite catalysts are discussed.Next,several clean energy catalytic reactions performed over the synergistic composite catalysts are illustrated.Eventually,the encountering challenges and recommendations for the future advancement of synergistic structure in energy-transformation electrocatalysis are outlined.
文摘Visual object-tracking is a fundamental task applied in many applications of computer vision. Particle filter is one of the techniques which has been widely used in object tracking. Due to the virtue of extendability and flexibility on both linear and non-linear environments, various particle filter-based trackers have been proposed in the literature. However, the conventional approach cannot handle very large videos efficiently in the current data intensive information age. In this work, a parallelized particle filter is provided in a distributed framework provided by the Hadoop/Map-Reduce infrastructure to tackle object-tracking tasks. The experiments indicate that the proposed algorithm has a better convergence and accuracy as compared to the traditional particle filter. The computational power and the scalability of the proposed particle filter in single object tracking have been enhanced as well.