Parameter optimization of gravity density inversion based on correlation searching and the golden section algorithm

For density inversion of gravity anomaly data, once the inversion method is determined, the main factors affecting the inversion result are the inversion parameters and subdivision scheme. A set of reasonable inversion parameters and subdivision scheme can, not only improve the inversion process efficiency, but also ensure inversion result accuracy. The gravity inversion method based on correlation searching and the golden section algorithm is an effective potential field inversion method. It can be used to invert 2D and 3D physical properties with potential data observed on flat or rough surfaces. In this paper, we introduce in detail the density inversion principles based on correlation searching and the golden section algorithm. Considering that the gold section algorithm is not globally optimized. we present a heuristic method to ensure the inversion result is globally optimized. With a series of model tests, we systematically compare and analyze the inversion result efficiency and accuracy with different parameters. Based on the model test results, we conclude the selection principles for each inversion parameter with which the inversion accuracy can be obviously improved.

On a New Equation for Critical Current Density Directly in Terms of the BCS Interaction Parameter, Debye Temperature and the Fermi Energy of the Superconductor

Recasting the BCS theory in the larger framework of the Bethe-Salpeter equation, a new equation is derived for the temperature-dependent critical current density jc(T) of an elemental superconductor (SC) directly in terms of the basic parameters of the theory, namely the dimensionless coupling constant [N(0)V], the Debye temperature θD and, additionally, the Fermi energy EF—unlike earlier such equations based on diverse, indirect criteria. Our approach provides an ab initio theoretical justification for one of the latter, text book equations invoked at T = 0 which involves Fermi momentum;additionally, it relates jc with the relevant parameters of the problem at T ≠ 0. Noting that the numerical value of EF of a high-Tc SC is a necessary input for the construction of its Fermi surface—which sheds light on its gap-structure, we also briefly discuss extension of our approach for such SCs.

Cranny density parameters and porosity measured by elastic wave method in quasi-isotropic cranny rock masses

According to the characteristic of elastic waves propagation in medium and the application of elastic waves method in rock mass engineering, the cranny mass with random crannies was regarded as quasi-isotropic cranny mass. In accordance with the rock rupture mechanics, principle of energy balance and Castiglano＇s theorem, the relationship of effective dynamic parameters of elasticity （E, v, G） and cranny density parameters or porosity was put forward. On this basis, through the theory of elastic waves propagation in isotropic medium, the relationship between the elastic wave velocity and cranny density parameters and porosity was set up. The theoretical research results show that, in this kind of cranny rock masses, there is nonlinear relationships between the effective dynamic parameters of elasticity and wave velocities and the cranny density parameter or porosity; and with the increase of cranny density parameter or porosity of cranny rock masses, the effective dynamic modulus and the elastic wave velocities of cranny rock masses will decrease; and at the same time, when the cranny density parameter or porosity is very small, the effective dynamic modulus of elasticity and the elastic wave velocities change with the cranny density parameter, which can explain the sensitivity of effective elastic parameters and elastic wave velocities to cranny rock masses.

Dependablity study on near-infrared parameters of blood oxygen and microvessel density of mammary gland phyma

Objective:To detect the reliability of near-infrared parameters of blood oxygen of mammary gland phyma from the microvessel density of tumor.Methods:181 cases of mammary gland phyma who had accepted the examination of the near-infrared TBO-I dual-wave length mammary gland phyma detector were classified by near-infrared parameters of blood oxygen,and were performed the pathologic examination to ascertain whether the tumor was benign or malignant.Among these cases,intratumoral microvessel density of 20 cases of malignant phyma and 20 cases of benign phyma were confirmed by S-P immunohistochemical method,then the relationship between near-infrared parameters and microvessel density were analyzed by medical statistics.Results:(1)The microvessel density and blood concentration of 28 cases of the"high blood" tumor were 24.56±8.110 and 1.891±0.850 respectively.The microvessel density and blood concentration of 12 cases of the"low blood"tumor were 17.98±8.729 and 0.698±0.283 respectively.There was significant difference between the"high blood"and"low blood"tumors(P<0.05).(2)The intratumoral microvessel density and blood concentration were linearly correlated respectively,and the linear correlation coefficient r=0.4208(P<0.05)in 40 cases of mammary gland phyma. Conclusion:The intratumoral microvessel density and blood concentration of benign or malignant mammary gland phyma were linearly correlated.Blood concentration(one of near-infrared parameters)is reliable to be used as diagnosis criterion of malignant mammary gland phyma.

A NEW FORMULA FOR CALCULATING THE DENSITY OF METALS FROM THEIR ATOMIC STRUCUTURE PARAMETERS

Bused on the consideration o (?) mass and volume of one atom, a new formula tor calculating the density of simple metal substance from their atomic structure parameters is established. The densities of 66 metals in the periodic table were calculated from this formula. The calculated results are in agreement with the measured values reported in literature. The advantage of the present formula over the others is brie fly discussed.

Cross-linking density and aging constitutive model of HTPB coating under prestrain thermal accelerated aging

In order to study the cross-linking density and aging constitutive relationship of HTPB coating during storage,the thermal accelerated aging tests at 0%,3%,6%and 9%prestrains were carried out.The crosslinking density of HTPB coating at different aging stages were tested using low-field^1 H NMR and the variation of cross-linking density was analyzed.The aging model of cross-linking density considering the chemical aging and the physical stretching factors was established.The uniaxial tensile tests were carried out on HTPB coating at different aging stages and the cross-linking density was introduced into Ogden hyperelastic constitutive model as a characterization parameter of correction coefficient.Combined with uniaxial tensile test results,a prestrain aging constitutive model of HTPB coating was established.The results show that the cross-linking density of HTPB coating increases rapidly at first and then slowly with the increase of thermal accelerated aging time without prestrain.Under prestrain conditions,the crosslinking density of HTPB coating decreases at the early stage,and increases rapidly at first and then slowly at the middle and late stages of thermal accelerated aging.The correlation coefficients of aging model of cross-linking density and aging constitutive model with test results are R>0.9500 and R>0.9900 respectively,which can be used to accurately describe the cross-linking density and aging constitutive relationship of HTPB coating under prestrain accelerated thermal aging conditions.

Effect of process parameters on density of magnesium alloy parts by low-pressure expendable pattern casting

The combination of magnesium alloys with the low-pressure expendable pattern casting(LP-EPC) process would bright future for application of magnesium alloys. The researches are focused on the effect of process parameters on the internal casting quality of magnesium alloy parts. AZ91D magnesium alloy castings were produced for different combinations of the LP-EPC process parameters. Specifically,pouring temperature,vacuum,filling velocity and coupling action of these factors were manipulated to observe their effect on the casting porosity and density distribution. The results indicate that the pouring temperature with LP-EPC process is lower than it in gravity casting. The selected process parameters,such as vacuum,filling velocity and coupled modes of them,must ensure melt metal flowing front profile exhibiting smooth and convex shape. The optimal process parameters for the castings are pouring temperature 983-1 023 K,vacuum 0.02-0.03 MPa,filling velocity 60-95 mm/s,and simultaneous filling with sucking.

Density Matrix for Mesoscopic Distributed Parameter Circuits

Under the Born-von-Karmann periodic boundary condition, we propose a quantization scheme for non-dissipative distributed parameter circuits (i.e. a uniform periodic transmission line). We find the unitary operator for diagonalizing the Hamiltonian of the uniform periodic transmission line. The unitary operator is expressed in a coordinate representation that brings convenience to deriving the density matrix rho(q,q',beta). The quantum fluctuations of charge and current at a definite temperature have been studied. It is shown that quantum fluctuations of distributed parameter circuits, which also have distributed properties, are related to both the circuit parameters and the positions and the mode of signals and temperature T. The higher the temperature is, the stronger quantum noise the circuit exhibits.

Parameterization of COSMO-RS model for ionic liquids

The adjustable parameters in the popular conductor-like screening model for real solvents(COSMO-RS)within the Amsterdam density functional(ADF)framework have been re-optimized to fit for the systems containing ionic liquids(ILs).To get the optimal values of misfit energy constant a^0,hydrogen bond coefficient c_(hb)and effective contact surface area of a segment a_(eff),2283 activity coefficient data points at infinite dilution and 1433 CO_2 solubility data points exhaustively collected from references were used as training set.The average relative deviations(ARDs)of activity coefficients at infinite dilution and CO_2 solubility between experimental data and predicted values are 32.22%and17.61%,respectively,both of which are significantly lower than the original COSMO-RS versions.Predictions for other activity coefficients of solutes in ILs,solubility data of CO_2 in pure ILs and the binary mixtures of ILs at either high or low temperatures,and vapor–liquid equilibrium(VLE)for binary systems involving ILs have also been performed to demonstrate the validity of the parameterization of COSMO-RS model for ILs.The results showed that the predicted results by COSMO-RS model with the new optimized parameters are in much better agreement with experimental data than those by the original versions over a wide temperature and pressure range.The COSMO-RS model for ILs presented in this work improves the prediction accuracy of thermodynamic properties for the systems containing ILs,which is always highly desirable for general chemical engineers.

Effect of power parameter and induction coil on magnetic field in cold crucible during continuous melting and directional solidification

Bottomless electromagnetic cold crucible is a new apparatus for continuous melting and directional solidification;however,improving its power efficiency and optimizing the configuration are important for experiment and production.In this study,a 3-D finite element (FE) method based on experimental verification was applied to calculate the magnetic flux density (Bz).The effects of the power parameters and the induction coil on the magnetic field distribution in the cold crucible were investigated.The results show that higher current intensity and lower frequency are beneficial to the increase of Bz at both the segment midpoint and the slit location.The induction coil with racetrack section can induce greater Bz,and a larger gap between the induction coil and the shield ring increases Bz.The mechanism for this effect is also discussed.

Probabilistic model and analysis of coupled train-ballasted track-subgrade system with uncertain structural parameters

Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system.

Optimization of Blasting Parameters Using Regression Models in Ratcon and NSCE Granite Quarries, Ibadan, Oyo State, Nigeria

This research examines optimization of blasting parameters for economic production of granite aggregates in Ratcon and NSCE quarries located atIbadan,OyoState. Samples were collected from the study areas for the determination of rock density and porosity. Schmidt hammer was used for in situ determination of rock hardness. Uniaxial compressive strength of in situ rock was estimated from the values obtained from Schmidt hammer rebound hardness test and density determined from laboratory test. Blasting data were collected from the study areas for optimization. Multiple regression analysis using computer aided solution SPSS (Statistical Package for the Social Sciences) was used to analyse data obtained from the laboratory test, field test and the study areas. The estimated mean uniaxial compressive strength value of NSCE is 240 MPa and that of Ratcon is 200 MPa and their average densities and average porosities are2.63g/cm3,2.55g/cm3, 1.88% and 2.25% respectively. Eleven parameters were input into the multiple regression analysis to generate the models. Two parameters out of eleven input parameters such as geometric volume of blast (Y1) and number of boulders generated after blasting (Y2) were dependent variables and the remaining nine such as X1 (Drill hole diameter), X2 (Drill hole depth), X3 (Spacing), X4 (Burden), X5 (Average charge per hole), X6 (Rock density), X7 (Porosity), X8 (Uniaxial compressive strength) and X9 (Specific charge) were input as independent variables. The results of the models show that out of the nine independent variables seven of them that is X1 (Borehole diameter), X2 (Borehole depth), X3 (Spacing), X4 (Burden), X5 (Average charge per hole), X8 (Uniaxial compressive strength) and X9 (Specific charge) have significant contribution to the models while X6 (Rock Density) and X7 (Porosity) have insignificant contribution they are therefore automatically deleted by the SPSS. The result of the models developed for the optimization reveals that blasting number 5 gives the required product at lowest possible cost. From the result, the cost of secondary blasting has been reduced and volume of the blasted rock has been increased with low cost of explosives, the parameters that give this result have been chosen as optimum parameters.

Effects of process parameters on nonaqueous gelcasting for copper powder

An approach to fabricate sintered copper with high green strength and high sintered density using nonaqueous gelcasting technol- ogy is presented in this study. The effects of various gelcasting processing parameters such as monomer content, monomer/crosslinker ratio, initiator content, dispersant dosage, and temperature on the flexural strength of dried green bodies and the relative density of sintered bodies were studied to obtain better microstructures and properties. The appropriate process parameters obtained for copper gelcasting are as follows monomer content, 20vol%-30vol% （based on the total volume of reagents）; monomer/crosslinker ratio, 10：1 to 20：1; initiator content, 3vol%-4vol% （based on the volume of the monomer）; dispersant dosage, 1.5wt%-2.5wt% （based on the mass of the copper powder）; and reaction temperature, 65-75℃.

Evolutionary history shapes variation of wood density of tree species across the world

The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide,we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species.We assessed phylogenetic signal in different taxonomic(e.g.,angiosperms and gymnosperms)and ecological(e.g.,tropical,temperate,and boreal)groups of tree species,explored the biogeographical and phylogenetic patterns of wood density,and quantified the relative importance of current environmental factors(e.g.,climatic and soil variables)and evolutionary history(i.e.,phylogenetic relatedness among species and lineages)in driving global wood density variation.We found that wood density displayed a significant phylogenetic signal.Wood density differed among different biomes and climatic zones,with higher mean values of wood density in relatively drier regions(highest in subtropical desert).Our study revealed that at a global scale,for angiosperms and gymnosperms combined,phylogeny and species(representing the variance explained by taxonomy and not direct explained by long-term evolution process)explained 84.3%and 7.7%of total wood density variation,respectively,whereas current environment explained 2.7%of total wood density variation when phylogeny and species were taken into account.When angiosperms and gymnosperms were considered separately,the three proportions of explained variation are,respectively,84.2%,7.5%and 6.7%for angiosperms,and 45.7%,21.3%and 18.6%for gymnosperms.Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.

Effect of sintering parameters on powder injection molded Ti(C, N)-based cermets

Effect of two-stage sintering parameters such as heating rate, top sintering temperature and holding time, sintering temperature and holding time at the second stage on relative density, transverse rupture strength(TRS) and microstructures of powder injection molded Ti(C, N)-based cermets were investigated, by means of Archimedes’s method, three-point bending test and micrographic analysis. The results show that the optimum sintering cycle for powder injection molded Ti(C, N)-based cermets comprises rapid heating (10℃/min) at low temperatures, slow heating (5℃/min) at intermediate temperatures, holding at the highest sintering temperature (1420℃) for a short time (10min), and holding at the second stage (1360℃) for a longer time (6h) to avoid grain coarsening, and that its TRS reaches 624MPa, and there are little pores in their microstructures.

The Bowing Parameters of Ca_χMg_1-χO Ternary Alloys

On the basis of first principles calculations using density functional theory, we explore the structural and electronic properties of two binaries: CaO and MgO in rock salt structures. Structural properties of the semiconductor CaχMg1-χO alloys are derived from total-energy minimization within the General Gradient Approximation. The band gap bowing parameters dependence is very powerful Calcium composition. The results offer that an average bowing parameter of CaχMg1-χO alloys is b = ~0.583$ eV. We analyzed the volume deformation, charge transfer and structural relaxation effects of the CaχMg1-χO alloys.

Calculation of the Structural Parameters, and DOS of TaB2 with p6/mmm Space Group Using DFT

In this paper, the structural parameters, and density of the states of TaB2 compound have been calculated, and investigated in hexagonal phase with P6/mmm space group. The calculations have been performed with ultra-soft pseudo-potential in the frame work of Density Functional Theory （DFT） by using the Quantum Espresso package. With respect to high quantity of bulk modulus, and low quantity of the volume it is being understood that this compound has a very hard structure. The figure of density of states shows that this compound is a kind of metal. The obtained results from this research have good accord with experimental results, and with the same researches.

Experimental Measurement of the Generalized Stokes Parameters of a Radially Polarized Random Electromagnetic Beam

Utilizing the Young’s double slits and Mach-Zehnder interferometer, we proposed an experimental method to measure the generalized Stokes parameters of a radially polarized random electromagnetic beam. After the partially coherent beam propagating through the Young’s double slits, the interference fringe is obtained by the help of a Mach-Zehnder interferometer consisting of apertures, quarter-wave plates and polarizers. The electric cross-spectral density matrix is detected by the coherence degree of interference fringe and the density of each single slit. The generalized Stokes parameters can be obtained from the electric cross-spectral density matrix. This experiment measures the generalized Stokes parameters of the random electromagnetic beam successfully. The results show that the spectral degree of coherence for copolarized cases (xx and yy) is similar with that for cross-polaried cases (xy and yx) for the radially polarized random electromagnetic beam. This method will help us determine the change of the polarization and coherence of the light in propagation by detecting the change of the generalized Stokes parameters.

Chinese Evaluated Nuclear Parameter Library(CENPL)(Ⅰ)

As a library of nuclear basic data and nuclear model parameters for nuclear model calculations,Chinese Evaluated Nuclear Parameter Library(CENPL)at Chinese Nuclear Data Center(CNDC)consists of six sub-libraries and is still under development.Most of the data fries for this library have beenset up.These sub-libraries have been used to retrieve the data required for nuclear model calculations andother purposes.