We propose a simple model of colloidal suspension,whereby individual particles change their diffusivity from high(hot)to low(cold),as the local concentration of their closest peers grows larger than a certain threshol...We propose a simple model of colloidal suspension,whereby individual particles change their diffusivity from high(hot)to low(cold),as the local concentration of their closest peers grows larger than a certain threshold.Such a non-reciprocal interactive mechanism is known in biology as quorum sensing.Upon tuning the parameters of the adopted quorum sensing protocol,the suspension is numerically shown to go through a variety of two-phase(hot and cold)configurations.This is an archetypal model with potential applications in robotics and social studies.展开更多
Synthetic conditions and ligands are the key structural defining factors of metal-organic frameworks(MOFs).Therefore,reasonable optimization of these aspects is considered to be an effective means for designing materi...Synthetic conditions and ligands are the key structural defining factors of metal-organic frameworks(MOFs).Therefore,reasonable optimization of these aspects is considered to be an effective means for designing materials with novel structures and target functions.Herein,two novel Co(Ⅱ)-based MOFs,namely[Co(HL)(dibp)]_(n)(HL-8) and{[Co_(2)(L)(OH)(dibp)]·DMA}_n(HL-9)(H_(3)L=2',6'-dimethyl-[1,1'-biphenyl]-3,4',5-tricarboxylic acid;dibp=4,4'-di(1H-imidazol-1-yl)-1,1-biphenyl]),have been hydrothermally synthesized and structurally characterized.HL-8 crystallizes in the orthorhombic system (Pna2_(1)) with a grid layer structure,while HL-9 crystallizes in the monoclinic P2_(1)/n space group assembled through Co_(4)(OH)_(2)clusters with organic ligands.Remarkably,benefiting from the finite cage-like structure,HL-9 exhibited enhanced performance in carbon dioxide(CO_(2)) adsorption/catalytic transformation and excellent size selectivity during dye molecular adsorption process.展开更多
Sb-based organic–inorganic hybrid metal halides(OIHMHs)with[SbCl5]2−units have been widely reported due to high photoluminescence quantum yield(PLQY)and occasional multiple self-trapped exciton(STE)emission bands mai...Sb-based organic–inorganic hybrid metal halides(OIHMHs)with[SbCl5]2−units have been widely reported due to high photoluminescence quantum yield(PLQY)and occasional multiple self-trapped exciton(STE)emission bands mainly out of singlet and triplet states,and their multi-band emission is important in white light-emitting diode(WLED).However,not all these OIHMH compounds can produce both emissions out of singlet STE and triplet STE at room temperature simultaneously.It is crucial to consider how the singlet STE generates and retains to emit light at room temperature for this material’s design and application.Herein,a strategy is proposed that can significantly lift Sb halide PLQY by synthesizing two Sb-based OIHMHs using organic amine cations of different-sized and-quantity,which modulate the distance of neighboring emission centers.Therein,the occurrence of singlet STE emission is found to be closely related to the distance of[SbCl_(5)]^(2)−units and local unit distortion in the lattice.The larger distance can produce smaller local distortions,favoring the formation of the singlet STE emission band at higher energy.This is the first work to reveal the relationship between the local structure and the origin of the singlet STE emission band,providing new insights into the modulation of the Sb-based OIHMH’s emission.展开更多
Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calcu...Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.展开更多
Ambient Assisted Living(AAL) is becoming an important research field. Many technologies have emerged related with pervasive computing vision, which can give support for AAL. One of the most reliable approaches is base...Ambient Assisted Living(AAL) is becoming an important research field. Many technologies have emerged related with pervasive computing vision, which can give support for AAL. One of the most reliable approaches is based on wireless sensor networks(WSNs). In this paper, we propose a coverage-aware unequal clustering protocol with load separation(CUCPLS) for data gathering of AAL applications based on WSNs. Firstly, the coverage overlap factor for nodes is introduced that accounts for the degree of target nodes covered. In addition, to balance the intra-cluster and inter-cluster energy consumptions, different competition radiuses of CHs are computed theoretically in different rings, and smaller clusters are formed near the sink. Moreover, two CHs are selected in each cluster for load separation to alleviate the substantial energy consumption difference between a single CH and its member nodes. Furthermore, a backoff waiting time is adopted during the selection of the two CHs to reduce the number of control messages employed. Simulation results demonstrate that the CUCPLS not only can achieve better coverage performance, but also balance the energy consumption of a network and prolong network lifetime.展开更多
In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as...In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as an example. In previous wind tunnel free-flight tests, the similarity law of vertical, downward, moving submunition was used to design submunitions at different positions in different initial-velocity directions, which resulted in large discrepancies between wind tunnel test results and real flight. In a wind tunnel test, each submunition has an independent time-reduction ratio with respect to the dispenser. Even if the separation trajectory of a single submunition is accurate, there will be errors in the position of each submunition at a given time. Therefore, it is necessary to determine the time-reduction ratio between submunitions, and to modify the test results later. In order to ensure the accuracy of wind tunnel test results, the similarity law of a freeflight test in a wind tunnel is derived in this paper. The time-correction scheme to ensure motion similarity between submunitions is solved. Numerical simulation is used to simulate the separation of a wind tunnel test and real aircraft, and the motion parameters of different submunitions are solved. The results show that the new similarity laws derived for different types of submunitions can greatly reduce the errors caused by previous similarity laws. In addition to the case for the separation of a cluster munition, the similarity law can also be applied to the free-flight test design of wind tunnels for vertical separation and horizontal separation of other kinds of aircraft.展开更多
Amylose tris(3,5-dimethylphenylcarbamate) (ADMPC) coated on a kind of small particle silica gel was pre-pared. On this ADMPC chiral stationary phase (CSP), the direct enantiomeric separation of six novel chiral transi...Amylose tris(3,5-dimethylphenylcarbamate) (ADMPC) coated on a kind of small particle silica gel was pre-pared. On this ADMPC chiral stationary phase (CSP), the direct enantiomeric separation of six novel chiral transi-tion metal tetrahedral clusters has firstly been achieved using n-hexane as the mobile phase containing various al-cohols as modifiers. The effect of mobile phase modifiers and the structural variation of the solutes on their reten-tion factors (k) and resolutions (Rs) were investigated. The result suggests that not only the structure and concentra-tion of alcohol in mobile phase, but also the structural differences in racemates can have a pronounced effect on enantiomeric separation. ADMPC-CSP is a suitable CSP for the optical resolution of chiral tetrahedral cluster by HPLC.展开更多
Ac susceptibility at low temperatures of Pro.75Nao.25MnO3-xFexO3 （0 ≤ x ≤0.30） is investigated. The peak value of the real component of ac susceptibility X＇ at the freezing temperature Tf is suppressed with the i...Ac susceptibility at low temperatures of Pro.75Nao.25MnO3-xFexO3 （0 ≤ x ≤0.30） is investigated. The peak value of the real component of ac susceptibility X＇ at the freezing temperature Tf is suppressed with the increasing frequency. The peak value of X＇ shows a linear relation between Tf and the logarithm of the frequency ω. The normalized slope P = △Tf/Tf△lgco, which is much lower than canonical insulating spin glass systems in which 0.06 ≤ P ≤ 0,08. The peak value of the imaginary component of the ac susceptibility X＂ at Tf for the x= 0, 0.02, 0.30 samples increases with increasing frequency, suggesting a cluster glass ground state with a coexistence of charge-ordered phase and correlated ferromagnetic clusters in spin glass matrix. The peak value ofx＂ at Tf for the x = 0.10 sample decreases with increasing frequency, suggesting a phase separation ground state. The peak value of X＂at Tf for the x = 0.05 sample decreases with increasing frequency for ω ≤52 Hz and increases subsequently till 701 Hz, and then decreases with further increasing frequency for ω ≥ 1501 Hz. This complex behaviour is ascribed to the competition between the effects of large and little ferromagnetic clusters in the sample. The ground state of x = 0.05 sample is a transition state from cluster glass to phase separation.展开更多
In work, it is constructed a discrete mathematical model of motion of a perfect fluid. The fluid is represented as an ensemble of identical so-called liquid particles, which are in the form of extended geometrical obj...In work, it is constructed a discrete mathematical model of motion of a perfect fluid. The fluid is represented as an ensemble of identical so-called liquid particles, which are in the form of extended geometrical objects: circles and spheres for two-dimensional and three-dimensional cases, respectively. The mechanism of interaction between the liquid particles on a binary level and on the level of the n-cluster is formulated. This mechanism has previously been found by the author as part of the mathematical modeling of turbulent fluid motion. In the turbulence model was derived and investigated the potential interaction of pairs of liquid particles, which contained a singularity of the branch point. Exactly, this is possible to build in this article discrete stochastic-deterministic model of an ideal fluid. The results of computational experiment to simulate various kinds of flows in two-dimensional and three-dimensional ensembles of liquid particles are presented. Modeling was carried out in the areas of quadratic or cubic form. On boundary of a region satisfies the condition of elastic reflection liquid particles. The flows with spontaneous separation of particles in a region, various kinds of eddy streams, with the quite unexpected statistical properties of an ensemble of particles characteristic for the Fermi-Pasta-Ulam effect were found. We build and study the flow in which the velocity of the particles is calibrated. It was possible using the appropriate flows of liquid particles of the ensemble to demonstrate the possibility to reproduce any prescribed image by manipulating the parameters of the interaction. Calculations of the flows were performed with using MATLAB software package according to the algorithms presented in this article.展开更多
基金supported by the National Natural Science Foundation of China(12375037 and 11935010)
文摘We propose a simple model of colloidal suspension,whereby individual particles change their diffusivity from high(hot)to low(cold),as the local concentration of their closest peers grows larger than a certain threshold.Such a non-reciprocal interactive mechanism is known in biology as quorum sensing.Upon tuning the parameters of the adopted quorum sensing protocol,the suspension is numerically shown to go through a variety of two-phase(hot and cold)configurations.This is an archetypal model with potential applications in robotics and social studies.
基金supported by the National Natural Science Foundation of China(Nos.21902022,21601028,81903501 and 22061019)Qingchuang Science and Technology Plan of Shandong Province(No.2021KJ054)+1 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2018LB018,ZR2019QB026 and ZR2020KB014)Scientific Research Foundation of Dezhou University(Nos.30101905,30102708 and 30102701)。
文摘Synthetic conditions and ligands are the key structural defining factors of metal-organic frameworks(MOFs).Therefore,reasonable optimization of these aspects is considered to be an effective means for designing materials with novel structures and target functions.Herein,two novel Co(Ⅱ)-based MOFs,namely[Co(HL)(dibp)]_(n)(HL-8) and{[Co_(2)(L)(OH)(dibp)]·DMA}_n(HL-9)(H_(3)L=2',6'-dimethyl-[1,1'-biphenyl]-3,4',5-tricarboxylic acid;dibp=4,4'-di(1H-imidazol-1-yl)-1,1-biphenyl]),have been hydrothermally synthesized and structurally characterized.HL-8 crystallizes in the orthorhombic system (Pna2_(1)) with a grid layer structure,while HL-9 crystallizes in the monoclinic P2_(1)/n space group assembled through Co_(4)(OH)_(2)clusters with organic ligands.Remarkably,benefiting from the finite cage-like structure,HL-9 exhibited enhanced performance in carbon dioxide(CO_(2)) adsorption/catalytic transformation and excellent size selectivity during dye molecular adsorption process.
基金supported by the Guangxi NSF(No.2020GXNSFDA238004)the Bagui Scholar project of Guangxi provincethe Scientific and Technological Bases and Talents of Guangxi(No.Guike AD21238027).
文摘Sb-based organic–inorganic hybrid metal halides(OIHMHs)with[SbCl5]2−units have been widely reported due to high photoluminescence quantum yield(PLQY)and occasional multiple self-trapped exciton(STE)emission bands mainly out of singlet and triplet states,and their multi-band emission is important in white light-emitting diode(WLED).However,not all these OIHMH compounds can produce both emissions out of singlet STE and triplet STE at room temperature simultaneously.It is crucial to consider how the singlet STE generates and retains to emit light at room temperature for this material’s design and application.Herein,a strategy is proposed that can significantly lift Sb halide PLQY by synthesizing two Sb-based OIHMHs using organic amine cations of different-sized and-quantity,which modulate the distance of neighboring emission centers.Therein,the occurrence of singlet STE emission is found to be closely related to the distance of[SbCl_(5)]^(2)−units and local unit distortion in the lattice.The larger distance can produce smaller local distortions,favoring the formation of the singlet STE emission band at higher energy.This is the first work to reveal the relationship between the local structure and the origin of the singlet STE emission band,providing new insights into the modulation of the Sb-based OIHMH’s emission.
文摘Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.
基金supported by the National Nature Science Foundation of China (61170169, 61170168)
文摘Ambient Assisted Living(AAL) is becoming an important research field. Many technologies have emerged related with pervasive computing vision, which can give support for AAL. One of the most reliable approaches is based on wireless sensor networks(WSNs). In this paper, we propose a coverage-aware unequal clustering protocol with load separation(CUCPLS) for data gathering of AAL applications based on WSNs. Firstly, the coverage overlap factor for nodes is introduced that accounts for the degree of target nodes covered. In addition, to balance the intra-cluster and inter-cluster energy consumptions, different competition radiuses of CHs are computed theoretically in different rings, and smaller clusters are formed near the sink. Moreover, two CHs are selected in each cluster for load separation to alleviate the substantial energy consumption difference between a single CH and its member nodes. Furthermore, a backoff waiting time is adopted during the selection of the two CHs to reduce the number of control messages employed. Simulation results demonstrate that the CUCPLS not only can achieve better coverage performance, but also balance the energy consumption of a network and prolong network lifetime.
基金supported by the Advanced Research Fund for Weapons and Equipment Development of China。
文摘In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as an example. In previous wind tunnel free-flight tests, the similarity law of vertical, downward, moving submunition was used to design submunitions at different positions in different initial-velocity directions, which resulted in large discrepancies between wind tunnel test results and real flight. In a wind tunnel test, each submunition has an independent time-reduction ratio with respect to the dispenser. Even if the separation trajectory of a single submunition is accurate, there will be errors in the position of each submunition at a given time. Therefore, it is necessary to determine the time-reduction ratio between submunitions, and to modify the test results later. In order to ensure the accuracy of wind tunnel test results, the similarity law of a freeflight test in a wind tunnel is derived in this paper. The time-correction scheme to ensure motion similarity between submunitions is solved. Numerical simulation is used to simulate the separation of a wind tunnel test and real aircraft, and the motion parameters of different submunitions are solved. The results show that the new similarity laws derived for different types of submunitions can greatly reduce the errors caused by previous similarity laws. In addition to the case for the separation of a cluster munition, the similarity law can also be applied to the free-flight test design of wind tunnels for vertical separation and horizontal separation of other kinds of aircraft.
基金Project supported by Chinese Academy of Science (No. KY95-S1-205).
文摘Amylose tris(3,5-dimethylphenylcarbamate) (ADMPC) coated on a kind of small particle silica gel was pre-pared. On this ADMPC chiral stationary phase (CSP), the direct enantiomeric separation of six novel chiral transi-tion metal tetrahedral clusters has firstly been achieved using n-hexane as the mobile phase containing various al-cohols as modifiers. The effect of mobile phase modifiers and the structural variation of the solutes on their reten-tion factors (k) and resolutions (Rs) were investigated. The result suggests that not only the structure and concentra-tion of alcohol in mobile phase, but also the structural differences in racemates can have a pronounced effect on enantiomeric separation. ADMPC-CSP is a suitable CSP for the optical resolution of chiral tetrahedral cluster by HPLC.
基金supported by the Fundamental Research Funds for the Central Universities of China(Grant No.DL09BB31)the Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University,China (Grant No.LZUMMM2010004)+2 种基金the Fundamental Research Funds for the Central Universities of China(Grant No.DL09BB36)the National Natural Science Foundation of China(Grant No.31170518)the Research Fund of Heilongjiang Provincial Education Department(Grant No.12513040)
文摘Ac susceptibility at low temperatures of Pro.75Nao.25MnO3-xFexO3 （0 ≤ x ≤0.30） is investigated. The peak value of the real component of ac susceptibility X＇ at the freezing temperature Tf is suppressed with the increasing frequency. The peak value of X＇ shows a linear relation between Tf and the logarithm of the frequency ω. The normalized slope P = △Tf/Tf△lgco, which is much lower than canonical insulating spin glass systems in which 0.06 ≤ P ≤ 0,08. The peak value of the imaginary component of the ac susceptibility X＂ at Tf for the x= 0, 0.02, 0.30 samples increases with increasing frequency, suggesting a cluster glass ground state with a coexistence of charge-ordered phase and correlated ferromagnetic clusters in spin glass matrix. The peak value ofx＂ at Tf for the x = 0.10 sample decreases with increasing frequency, suggesting a phase separation ground state. The peak value of X＂at Tf for the x = 0.05 sample decreases with increasing frequency for ω ≤52 Hz and increases subsequently till 701 Hz, and then decreases with further increasing frequency for ω ≥ 1501 Hz. This complex behaviour is ascribed to the competition between the effects of large and little ferromagnetic clusters in the sample. The ground state of x = 0.05 sample is a transition state from cluster glass to phase separation.
文摘In work, it is constructed a discrete mathematical model of motion of a perfect fluid. The fluid is represented as an ensemble of identical so-called liquid particles, which are in the form of extended geometrical objects: circles and spheres for two-dimensional and three-dimensional cases, respectively. The mechanism of interaction between the liquid particles on a binary level and on the level of the n-cluster is formulated. This mechanism has previously been found by the author as part of the mathematical modeling of turbulent fluid motion. In the turbulence model was derived and investigated the potential interaction of pairs of liquid particles, which contained a singularity of the branch point. Exactly, this is possible to build in this article discrete stochastic-deterministic model of an ideal fluid. The results of computational experiment to simulate various kinds of flows in two-dimensional and three-dimensional ensembles of liquid particles are presented. Modeling was carried out in the areas of quadratic or cubic form. On boundary of a region satisfies the condition of elastic reflection liquid particles. The flows with spontaneous separation of particles in a region, various kinds of eddy streams, with the quite unexpected statistical properties of an ensemble of particles characteristic for the Fermi-Pasta-Ulam effect were found. We build and study the flow in which the velocity of the particles is calibrated. It was possible using the appropriate flows of liquid particles of the ensemble to demonstrate the possibility to reproduce any prescribed image by manipulating the parameters of the interaction. Calculations of the flows were performed with using MATLAB software package according to the algorithms presented in this article.
