Using Atmospheric Infrared Sounder (AIRS) humidity profiles, rainfall from the Tropical Rainfall Measuring Mission (TRMM) Global Precipitation Index (GPI), Quick Seatterometer (QSCAT) satellite-observed surfac...Using Atmospheric Infrared Sounder (AIRS) humidity profiles, rainfall from the Tropical Rainfall Measuring Mission (TRMM) Global Precipitation Index (GPI), Quick Seatterometer (QSCAT) satellite-observed surface winds, and SST from the Advanced Microwave Scanning Radiometer for NASA's Earth Observing System (AMSR_E), we analyzed the structure of the summer quasi-biweekly mode (QBM) over the western Pacific in 2003-2004. We find that the signal of 10 20-day oscillations in the western Pacific originates from the Philippine Sea, and propagates northwestward toward South China. The AIRS data reveal that the boundary-layer moisture provides preconditioning for QBM propagation, and leads the mid-troposphere moisture during the entire QBM cycle. The positive SST anomaly leads or is in-phase with the boundary- layer moistening, and may be a major contributor. Most likely, the 10 20-day SST anomaly positively feeds back to the atmosphere by moistening the boundary layer, destabilizing the troposphere, and leading the QBM to propagate northwestward in the western North Pacific. However, the ECMWF/TOGA (Tropical Ocean and Global Atmosphere) analysis does not display boundary-layer (BL) moisture anomalies leading the mid-troposphere moisture.展开更多
The broadband response of second harmonic generation(SHG)is experimentally observed in a two-dimensional(2D)quasi-random quasi-phase-matching(QPM)structure.A nonlinear conversion efficiency of more than 50%is obtained...The broadband response of second harmonic generation(SHG)is experimentally observed in a two-dimensional(2D)quasi-random quasi-phase-matching(QPM)structure.A nonlinear conversion efficiency of more than 50%is obtained.Due to the line-type distribution of the reciprocal vector,the second harmonic wave(SHW)covering a broad frequency band is efficiently radiated in the shape of one single spot or three spots instead of a stripe.This is believed to be favorable for its practical application and paves the way for the use of ultrahigh-bandwidth light sources and devices in modern optical technologies.展开更多
Notions of quasi-Jacobi bialgebroid and its Dirac-Jacobi structure are introduced.The necessary and sufficient conditions for a maximal isotropic subbundle L to be a DiracJacobi structure are proved.Meanwhile several ...Notions of quasi-Jacobi bialgebroid and its Dirac-Jacobi structure are introduced.The necessary and sufficient conditions for a maximal isotropic subbundle L to be a DiracJacobi structure are proved.Meanwhile several special examples are presented.展开更多
A new appraisal method(QDA, quasi-distribution appraisal) which could be used to evaluate the finite element analysis of multi-functional structure made of honeycomb sandwich materials is developed based on sub-sect...A new appraisal method(QDA, quasi-distribution appraisal) which could be used to evaluate the finite element analysis of multi-functional structure made of honeycomb sandwich materials is developed based on sub-section Bezier curve. It is established by simulating the distribution histogram data obtained from the numerical finite element analysis values of a satellite component with sub-section Bezier curve. Being dealt with area normalization method, the simulation curve could be regarded as a kind of probability density function(PDF), its mathematical expectation and the variance could be used to evaluate the result of finite element analysis. Numerical experiments have indicated that the QDA method demonstrates the intrinsic characteristics of the finite element analysis of multi-functional structure made of honeycomb sandwich materials, as an appraisal method, it is effective and feasible.展开更多
A three-dimensional off-lattice protein model with two species of monomers, hydrophobic and hydrophilic, is studied. Enligh- tened by the law of reciprocity among things in the physical world, a heuristic quasi-physic...A three-dimensional off-lattice protein model with two species of monomers, hydrophobic and hydrophilic, is studied. Enligh- tened by the law of reciprocity among things in the physical world, a heuristic quasi-physical algorithm for protein structure prediction problem is put forward. First, by elaborately simulating the movement of the smooth elastic balls in the physical world, the algorithm finds low energy configurations for a given monomer chain. An "off-trap" strategy is then proposed to get out of local minima. Experimental results show promising performance. For all chains with lengths 13≤n ≤55, the proposed algorithm finds states with lower energy than the putative ground states reported in literatures. Furthermore, for chain lengths n = 21, 34, and 55, the algorithm finds new low energy configurations different from those given in literatures.展开更多
A new complex AgCu(IO3)3 is synthesized by mild hydrothermal method and characterized by single-crystal X-ray diffraction and magnetization measurement.AgCu(IO3)3 is triclinic,space group P1,with a = 7.3081(1),b...A new complex AgCu(IO3)3 is synthesized by mild hydrothermal method and characterized by single-crystal X-ray diffraction and magnetization measurement.AgCu(IO3)3 is triclinic,space group P1,with a = 7.3081(1),b = 7.8089(1),c = 8.2447(1)A,α = 67.159(1),β = 74.982(1),γ = 80.982(1)°,and Z = 2.AgCu(IO3)3 is isostructral with Ag Pb(IO3)3.The structure of Ag Cu(IO3)3 consists of CuO6 chain columns parallel to the c axis,formed by corner-sharing Cu(1) and Cu(2) octahedra and flanked by corner-sharing IO3 groups; these CuO6 columns are cross-linked into a three-dimensional framework through I–O and Ag–O bonds.I(1),I(2) and I(3) are coordinated respectively with 3 oxygens on the same side to form trigonal pyramids confirming the presence of a stereochemically active lone pair of each I^5+ cation.In the CuO6 chain columns,Cu(1)O6 and Cu(2)O6 octahedra are tetragonally distorted with four shorter bonds in the square planes and two longer apical bonds.Cu(1)O6 octahedra were corner sharing with Cu(2)O6 octahedra with a shorter Cu(1)–O(1) bond in the square planes and a longer apical Cu(2)–O(1) bond,which forms a Cu(1)–Cu(2) magnetic chain along the c direaction.Magnetization measurement shows weak antiferromagnetic property in low temperature range.Ag Cu(IO3)3 provides a new example of a quasi-one-dimensional magnetic system.展开更多
Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By app...Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed.展开更多
Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper stud...Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper studies protein molecule from the algebraic point of view. The algebraic system (∑, +, *) is introduced, where ∑ is the set of 64 codons. According to the characteristics of (∑, +, *), a novel quasi-amino acids code classification method is introduced and the corresponding algebraic operation table over the set ZU of the 16 kinds of quasi-amino acids is established. The internal relation is revealed about quasi-amino acids. The results show that there exist some very close correlations between the properties of the quasi-amino acids and the codon. All these correlation relationships may play an important part in establishing the logic relationship between codons and the quasi-amino acids during the course of life origination. According to Ma F et al (2003 J. Anhui Agricultural University 30 439), the corresponding relation and the excellent properties about amino acids code are very difficult to observe. The present paper shows that (ZU, +,×) is a field. Furthermore, the operational results display that the eodon tga has different property from other stop codons. In fact, in the mitochondrion from human and ox genomic codon, tga is just tryptophane, is not the stop codon like in other genetic code, it is the case of the Chen W C et al (2002 Acta Biophysiea Siniea 18(1) 87). The present theory avoids some inexplicable events of the 20 kinds of amino acids code, in other words it solves the problem of 'the 64 codon assignments of mRNA to amino acids is probably completely wrong' proposed by Yang (2006 Progress in Modern Biomedicine 6 3).展开更多
Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elem...Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elements co-exist in the layer(e.g. Ni, Co and Mn). By contrast, the configuration tends to be ordered if the elements are Li and Mn. Here, by using special quasi-random structures(SQS) algorithm, the essential reasons of the ordering in a promising Li-rich Mn-based cathode material Li2MnO3 are investigated. The difference of internal energy and entropy between ordered and disordered materials is calculated. As a result, based on the Gibbs free energy, it is found that Li2MnO3 should have an ordered structure in TM layer. In comparison, structures with Ni-Mn ratio of 2:1 are predicted to have a disordered TM layer, because the entropy terms have larger impact on the structural ordering than internal energy terms.展开更多
In this paper, we consider the electromagnetic scattering from periodic chiral structures. The structure is periodic in one direction and invariant in another direction. The electromagnetic fields in the chiral medium...In this paper, we consider the electromagnetic scattering from periodic chiral structures. The structure is periodic in one direction and invariant in another direction. The electromagnetic fields in the chiral medium are governed by the Maxwell equations together with the Drude-Born-Fedorov equations. We simplify the problem to a two-dimensional scattering problem and we show that for all but possibly a discrete set of wave numbers, there is a unique quasi-periodic weak solution to the diffraction problem. The diffraction problem can be solved by finite element method. We also establish uniform error estimates for the finite element method and the error estimates when the truncation of the nonlocal transparent boundary operators takes place.展开更多
To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed...To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed based on the ordinary communication optical fiber. The sensing theories were analyzed, and the experimental studies were also carried out. The quasi-distributed sensing system based on optical time domain reflective technology was established. The detection wavelength and spatial resolution were analyzed, and the estimation formula of maximal number of sensing point was also given. The results show that the system can realize the quasi-distributed test of measurand with single fiber, which helps to simplify the in-out wires. Moreover it can take on the important task of long-term and continuous monitoring of prestress, which helps to realize the life cycle detection of prestress, and play an important role in the estimating of bridge health state.展开更多
A discrete variable structure control(DVSC) method for the linear time invariant systems with time delay was presented. The continuous time delay systems are first transformed into the standard discrete form which con...A discrete variable structure control(DVSC) method for the linear time invariant systems with time delay was presented. The continuous time delay systems are first transformed into the standard discrete form which contains no time delay by augmenting the state variables. Then the switching surface is determined by using the ideal quasi sliding mode. As it is difficult for the state trajectory to reach the switching surface exactly, the reaching condition in the form of approach law is used to design the controller. The deduced switching surface and controller contain not only the current step of state feedback but also some former steps of controls. Stability analysis with and without time delay information is also investigated in this paper. Numerical simulation was carried out to demonstrate the effectiveness and feasibility of the presented control method.展开更多
The famous paradoxes of quantum mechanics are created by the fact that elementary particles exist as the alternation between two structural states with different properties. This leads to probabilistic behavior, uncer...The famous paradoxes of quantum mechanics are created by the fact that elementary particles exist as the alternation between two structural states with different properties. This leads to probabilistic behavior, uncertainty principle, quantum tunneling, etc. The alternation of states plays the role of the frequency generator or clock. But for the objective character of quantum interactions the length standard also should exist in nature. Such analog of the rule must be physically real and in direct sense have to participate in the of particles interactions. Just this is the main role of physical vacuum. For such role vacuum should have quasi-crystalline geometry structure. Its symmetry requires in standard views only one fundamental change. In the quasicrystalline structure of the vacuum, the virtual shells of the real particles and atomic nuclei are not diffuse “clouds”, as is assumed today. Virtual environments are clearly structured and rigidly quantised shells with the geometric structure similar to fullerenes. Such shells are forming for greater than 99% of the known substance mass. Virtual particles forming such shells belong to the group of bosons and probably are just Higgs bosons existing in the ordinary matter. Chemical fullerenes form a series of discrete geometric structures. In a similar manner virtual analogues of fullerenes form a series of discrete masses, which really exist in the nature as a set of elementary particles and atomic nuclei masses.展开更多
基金supported by College Nature Science foundation of Jiangsu Province(07KJD170129): "Influence of QBM and ISO over the western Pacific on the rainfall of eastern China"supported by Special Public Sector Research(GYHY200806009): "Seasonal dynamic forcast and change trend preestimate of Typhoon on the background of global warming"Xiouhua Fu is supported by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC),NASA, and NOAA through their sponsor-ship of the IPRC
文摘Using Atmospheric Infrared Sounder (AIRS) humidity profiles, rainfall from the Tropical Rainfall Measuring Mission (TRMM) Global Precipitation Index (GPI), Quick Seatterometer (QSCAT) satellite-observed surface winds, and SST from the Advanced Microwave Scanning Radiometer for NASA's Earth Observing System (AMSR_E), we analyzed the structure of the summer quasi-biweekly mode (QBM) over the western Pacific in 2003-2004. We find that the signal of 10 20-day oscillations in the western Pacific originates from the Philippine Sea, and propagates northwestward toward South China. The AIRS data reveal that the boundary-layer moisture provides preconditioning for QBM propagation, and leads the mid-troposphere moisture during the entire QBM cycle. The positive SST anomaly leads or is in-phase with the boundary- layer moistening, and may be a major contributor. Most likely, the 10 20-day SST anomaly positively feeds back to the atmosphere by moistening the boundary layer, destabilizing the troposphere, and leading the QBM to propagate northwestward in the western North Pacific. However, the ECMWF/TOGA (Tropical Ocean and Global Atmosphere) analysis does not display boundary-layer (BL) moisture anomalies leading the mid-troposphere moisture.
基金supported by the National Natural Science Foundation of China [grant numbers 42030601 and 42205019]supported by a project funded by the China Postdoctoral Science Foundation [grant number 2022M710715]
基金by the National Natural Science Foundation of China under Grant No 10634080the National Basic Research Program of China under Grant Nos 2007CB613205 and 2007CB935703.
文摘The broadband response of second harmonic generation(SHG)is experimentally observed in a two-dimensional(2D)quasi-random quasi-phase-matching(QPM)structure.A nonlinear conversion efficiency of more than 50%is obtained.Due to the line-type distribution of the reciprocal vector,the second harmonic wave(SHW)covering a broad frequency band is efficiently radiated in the shape of one single spot or three spots instead of a stripe.This is believed to be favorable for its practical application and paves the way for the use of ultrahigh-bandwidth light sources and devices in modern optical technologies.
基金Supported by the Scientific Reseaxch Common Program of Beijing Municipal Commission of Education(SQKM201211232017)Supported by the Beijing Excellent Training Grant(2012D005007000005)Supported by the Funding Program for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality(11530500015)
文摘Notions of quasi-Jacobi bialgebroid and its Dirac-Jacobi structure are introduced.The necessary and sufficient conditions for a maximal isotropic subbundle L to be a DiracJacobi structure are proved.Meanwhile several special examples are presented.
基金Funded by the National Natural Science Foundation of China(No.61471024)National Marine Technology Program for Public Welfare,China(No.201505002-1)
文摘A new appraisal method(QDA, quasi-distribution appraisal) which could be used to evaluate the finite element analysis of multi-functional structure made of honeycomb sandwich materials is developed based on sub-section Bezier curve. It is established by simulating the distribution histogram data obtained from the numerical finite element analysis values of a satellite component with sub-section Bezier curve. Being dealt with area normalization method, the simulation curve could be regarded as a kind of probability density function(PDF), its mathematical expectation and the variance could be used to evaluate the result of finite element analysis. Numerical experiments have indicated that the QDA method demonstrates the intrinsic characteristics of the finite element analysis of multi-functional structure made of honeycomb sandwich materials, as an appraisal method, it is effective and feasible.
基金The National Natural Science Founda-tion of China (No.10471051) and the National Basic Research Program (973) of China (No.2004CB318000)
文摘A three-dimensional off-lattice protein model with two species of monomers, hydrophobic and hydrophilic, is studied. Enligh- tened by the law of reciprocity among things in the physical world, a heuristic quasi-physical algorithm for protein structure prediction problem is put forward. First, by elaborately simulating the movement of the smooth elastic balls in the physical world, the algorithm finds low energy configurations for a given monomer chain. An "off-trap" strategy is then proposed to get out of local minima. Experimental results show promising performance. For all chains with lengths 13≤n ≤55, the proposed algorithm finds states with lower energy than the putative ground states reported in literatures. Furthermore, for chain lengths n = 21, 34, and 55, the algorithm finds new low energy configurations different from those given in literatures.
文摘A new complex AgCu(IO3)3 is synthesized by mild hydrothermal method and characterized by single-crystal X-ray diffraction and magnetization measurement.AgCu(IO3)3 is triclinic,space group P1,with a = 7.3081(1),b = 7.8089(1),c = 8.2447(1)A,α = 67.159(1),β = 74.982(1),γ = 80.982(1)°,and Z = 2.AgCu(IO3)3 is isostructral with Ag Pb(IO3)3.The structure of Ag Cu(IO3)3 consists of CuO6 chain columns parallel to the c axis,formed by corner-sharing Cu(1) and Cu(2) octahedra and flanked by corner-sharing IO3 groups; these CuO6 columns are cross-linked into a three-dimensional framework through I–O and Ag–O bonds.I(1),I(2) and I(3) are coordinated respectively with 3 oxygens on the same side to form trigonal pyramids confirming the presence of a stereochemically active lone pair of each I^5+ cation.In the CuO6 chain columns,Cu(1)O6 and Cu(2)O6 octahedra are tetragonally distorted with four shorter bonds in the square planes and two longer apical bonds.Cu(1)O6 octahedra were corner sharing with Cu(2)O6 octahedra with a shorter Cu(1)–O(1) bond in the square planes and a longer apical Cu(2)–O(1) bond,which forms a Cu(1)–Cu(2) magnetic chain along the c direaction.Magnetization measurement shows weak antiferromagnetic property in low temperature range.Ag Cu(IO3)3 provides a new example of a quasi-one-dimensional magnetic system.
基金This work was supported by the National Natural Science Foundation of China (No.60274099) and the Foundation of Key Laboratory of Process Industry Automation, Ministry of Education
文摘Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed.
基金Project supported in part by the International Technology Collaboration Research Program of China (Grant No 2007DFA706700)
文摘Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper studies protein molecule from the algebraic point of view. The algebraic system (∑, +, *) is introduced, where ∑ is the set of 64 codons. According to the characteristics of (∑, +, *), a novel quasi-amino acids code classification method is introduced and the corresponding algebraic operation table over the set ZU of the 16 kinds of quasi-amino acids is established. The internal relation is revealed about quasi-amino acids. The results show that there exist some very close correlations between the properties of the quasi-amino acids and the codon. All these correlation relationships may play an important part in establishing the logic relationship between codons and the quasi-amino acids during the course of life origination. According to Ma F et al (2003 J. Anhui Agricultural University 30 439), the corresponding relation and the excellent properties about amino acids code are very difficult to observe. The present paper shows that (ZU, +,×) is a field. Furthermore, the operational results display that the eodon tga has different property from other stop codons. In fact, in the mitochondrion from human and ox genomic codon, tga is just tryptophane, is not the stop codon like in other genetic code, it is the case of the Chen W C et al (2002 Acta Biophysiea Siniea 18(1) 87). The present theory avoids some inexplicable events of the 20 kinds of amino acids code, in other words it solves the problem of 'the 64 codon assignments of mRNA to amino acids is probably completely wrong' proposed by Yang (2006 Progress in Modern Biomedicine 6 3).
基金Supported by National Key R&D Program of China(2016YFB0700600)Soft Science Research Project of Guangdong Province(No.2017B030301013)
文摘Layered transition metal(TM) oxides are one of the most widely used cathode materials in lithium-ion batteries. The atomic configuration in TM layer of these materials is often known to be random when multiple TM elements co-exist in the layer(e.g. Ni, Co and Mn). By contrast, the configuration tends to be ordered if the elements are Li and Mn. Here, by using special quasi-random structures(SQS) algorithm, the essential reasons of the ordering in a promising Li-rich Mn-based cathode material Li2MnO3 are investigated. The difference of internal energy and entropy between ordered and disordered materials is calculated. As a result, based on the Gibbs free energy, it is found that Li2MnO3 should have an ordered structure in TM layer. In comparison, structures with Ni-Mn ratio of 2:1 are predicted to have a disordered TM layer, because the entropy terms have larger impact on the structural ordering than internal energy terms.
基金The Special Funds for Major State Basic Research Projects (G1999032802) in China the NNSF (10076006) of China.
文摘In this paper, we consider the electromagnetic scattering from periodic chiral structures. The structure is periodic in one direction and invariant in another direction. The electromagnetic fields in the chiral medium are governed by the Maxwell equations together with the Drude-Born-Fedorov equations. We simplify the problem to a two-dimensional scattering problem and we show that for all but possibly a discrete set of wave numbers, there is a unique quasi-periodic weak solution to the diffraction problem. The diffraction problem can be solved by finite element method. We also establish uniform error estimates for the finite element method and the error estimates when the truncation of the nonlocal transparent boundary operators takes place.
文摘To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed based on the ordinary communication optical fiber. The sensing theories were analyzed, and the experimental studies were also carried out. The quasi-distributed sensing system based on optical time domain reflective technology was established. The detection wavelength and spatial resolution were analyzed, and the estimation formula of maximal number of sensing point was also given. The results show that the system can realize the quasi-distributed test of measurand with single fiber, which helps to simplify the in-out wires. Moreover it can take on the important task of long-term and continuous monitoring of prestress, which helps to realize the life cycle detection of prestress, and play an important role in the estimating of bridge health state.
文摘A discrete variable structure control(DVSC) method for the linear time invariant systems with time delay was presented. The continuous time delay systems are first transformed into the standard discrete form which contains no time delay by augmenting the state variables. Then the switching surface is determined by using the ideal quasi sliding mode. As it is difficult for the state trajectory to reach the switching surface exactly, the reaching condition in the form of approach law is used to design the controller. The deduced switching surface and controller contain not only the current step of state feedback but also some former steps of controls. Stability analysis with and without time delay information is also investigated in this paper. Numerical simulation was carried out to demonstrate the effectiveness and feasibility of the presented control method.
文摘The famous paradoxes of quantum mechanics are created by the fact that elementary particles exist as the alternation between two structural states with different properties. This leads to probabilistic behavior, uncertainty principle, quantum tunneling, etc. The alternation of states plays the role of the frequency generator or clock. But for the objective character of quantum interactions the length standard also should exist in nature. Such analog of the rule must be physically real and in direct sense have to participate in the of particles interactions. Just this is the main role of physical vacuum. For such role vacuum should have quasi-crystalline geometry structure. Its symmetry requires in standard views only one fundamental change. In the quasicrystalline structure of the vacuum, the virtual shells of the real particles and atomic nuclei are not diffuse “clouds”, as is assumed today. Virtual environments are clearly structured and rigidly quantised shells with the geometric structure similar to fullerenes. Such shells are forming for greater than 99% of the known substance mass. Virtual particles forming such shells belong to the group of bosons and probably are just Higgs bosons existing in the ordinary matter. Chemical fullerenes form a series of discrete geometric structures. In a similar manner virtual analogues of fullerenes form a series of discrete masses, which really exist in the nature as a set of elementary particles and atomic nuclei masses.