The potential energy curves of the ground state X2∑+g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees (RKR) method extrapolated by a Hulburt and Hirschfeler potential fu...The potential energy curves of the ground state X2∑+g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees (RKR) method extrapolated by a Hulburt and Hirschfeler potential function for longer internuclear distances. Solving the corresponding radial one-dimensional Schr?dinger equation of nuclear motion yields 22 bound vibrational levels above v=0. The comparison of these theoretical levels with the experimental data yields a mean absolute deviation of about 7.6 cm^-1 over the 23 levels. The highest vibrational level energy obtained using this method is 13308.16 cm?1 and the relative deviation compared with the experimental datum of 13408.49 cm^-1 is only 0.74%. The value from our method is much closer and more accurate than the value obtained by the quantum mechanical ab initio method by Bytautas. The reported agreement of the vibrational levels and dissociation energy with experiment is contingent upon the potential energy curve of the F2 ground state.展开更多
[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of ...[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year:the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate (Thuab) Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants(pomegranate and E. ciliate (Thuab) Hyland) when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.展开更多
A new physical current-voltage model for polysilicon thin-film transistors (poly-Si TFTs) is presented. Taking the V-shaped exponential distribution of trap states density into consideration,explicit calculation of ...A new physical current-voltage model for polysilicon thin-film transistors (poly-Si TFTs) is presented. Taking the V-shaped exponential distribution of trap states density into consideration,explicit calculation of surface potential is derived using the Lambert W function, which greatly improves computational efficiency and is critical in circuit simulation. Based on the exponential density of trap states and the calculated surface potential, the drain current characteristics of the subthreshold and the strong inversion region are predicted. A complete and unique drain current expression, including kink effect, is deduced. The model and the experimental data agree well over a wide range of channel lengths and operational regions.展开更多
To investigate the buckling and post buckling behaviors of elastic thin plate under frictionless unilateral restraint, enduring the coupling action of lognitudinal and transverse loads, the principle of minimum poten...To investigate the buckling and post buckling behaviors of elastic thin plate under frictionless unilateral restraint, enduring the coupling action of lognitudinal and transverse loads, the principle of minimum potential energy and variational method are used and series functions with unknown coefficients are taken as trial functions of functional to solve the large deflection and non linear bending problem of a thin plate and find relation curves between deflection of plate and loads. The proposed method can capture the buckling and post buckling behaviors of a thin plate in different geometrical and load boundary conditions. The analysis confirms that there occur snap and bifurcation behaviors in the post buckling stage of the plate. And these results show the validity of the variational method for solving buckling problems of thin plate.展开更多
A new 2-D variational method is proposed to calculate the vibrational energy levels of the symmetric P-H stretching vibration (vl) and the symmetric umbrella vibration (inversion vibration) (v2) of PH3^+(^~X...A new 2-D variational method is proposed to calculate the vibrational energy levels of the symmetric P-H stretching vibration (vl) and the symmetric umbrella vibration (inversion vibration) (v2) of PH3^+(^~X^2A″2) that has the tunneling effect. Because the symmetric internal Cartesian coordinates were employed in the calculations, the kinetic energy operator is very simple and the inversion vibrational mode is well characterized. In comparison with the often used I-D model to calculate the inversion vibrational energy levels, this 2-D method does not require an assmnption of reduced mass, and the interactions between the vl and v2 vibrational modes are taken into consideration. The calculated vibrational energy levels of PH3^+ are the first reported 2-D calculation, and the average deviation to the experimental data is less than 3 cm^-1 for the first seven inversion vibrational energy levels. This method has also been applied to calculate the vibrational energy levels of NH3. The application to NH3 is less successful, which shows some limitations of the method compared with a full dimension computation.展开更多
The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the ...The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.展开更多
Let G = (V, E) be a connected graph. X belong to V(G) is a vertex set. X is a 3-restricted cut of G, if G- X is not connected and every component of G- X has at least three vertices. The 3-restricted connectivity ...Let G = (V, E) be a connected graph. X belong to V(G) is a vertex set. X is a 3-restricted cut of G, if G- X is not connected and every component of G- X has at least three vertices. The 3-restricted connectivity κ3(G) (in short κ3) of G is the cardinality of a minimum 3-restricted cut of G. X is called κ3-cut, if |X| = κ3. A graph G is κ3-connected, if a 3-restricted cut exists. Let G be a graph girth g ≥ 4, κ3(G) is min{d(x) + d(y) + d(z) - 4 : xyz is a 2-path of G}. It will be shown that κ3(G) = ξ3(G) under the condition of girth.展开更多
Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the...Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.展开更多
In this paper, the buckling behavior of zigzag BN (Boron Nitride) nanotubes under bending is studied through molecular dynamics finite element method with Tersoff potential. The tube with namely (15, 0) BN zigzag ...In this paper, the buckling behavior of zigzag BN (Boron Nitride) nanotubes under bending is studied through molecular dynamics finite element method with Tersoff potential. The tube with namely (15, 0) BN zigzag tube is investigated. The critical bending buckling angle, moment and curvature are studied and examined with respect to the tube length-diameter ratios from 5 to 30. Effects of a SW (Stone-Wales) defect in the middle tube on the bending behavior are also discussed. The results show that the tube length affects significantly the bending behavior of these tubes. All tubes exhibit brittle fracture under bending. The buckling takes place at the middle in the compressive side of these tubes. These results are important information on the buckling behaviors of pristine and Stone-Wales BN nanotubes, which will be useful for their future applications.展开更多
We performed high-level ab initio calculations on electronic structure of Na K. The potential energy curves (PECs) of 10 Λ-S states correlated with the three lowest dissociation limits have been calculated. On the ba...We performed high-level ab initio calculations on electronic structure of Na K. The potential energy curves (PECs) of 10 Λ-S states correlated with the three lowest dissociation limits have been calculated. On the basis of the calculated PECs, the spectroscopic constants of the boundΛ-S states are obtained, which are in good agreement with experimental results. The maximum vibrational quantum numbers of the singlet ground state X^1Σ^+ and the triplet ground state a^3Σ^+ have been analyzed with the semiclassical scattering theory. Transition properties including transition dipole moments, Franck-Condon factors, and radiative lifetimes have been investigated. The research results indicate that such calculations can provide fairly reliable estimation of parameters for the ultracold alkali diatomic molecular experiment.展开更多
The newly synthesized element 117 and its alpha-decay chains are systematically investigated in the framework of the relativistic mean field theory with parameter sets NL-Z2 and TMA. The ground-state properties of the...The newly synthesized element 117 and its alpha-decay chains are systematically investigated in the framework of the relativistic mean field theory with parameter sets NL-Z2 and TMA. The ground-state properties of the superheavy nuclei on the alpha-decay chains of 294 117 and 293 117 are calculated. The experimental alpha-decay energies and ha Jr-lives of the two alpha-decay chains are reasonably reproduced by the model The detailed discussions on the binding energies, alpha-decay energies, half-lives, quadrupole deformations, potential energy curves, and single particle levels of the two alpha-decay chains are made.展开更多
The potential energy curves of the molecule CdS have been calculated for 245 internuclear distances in the range 2.15 A 〈 r ≤6.471 A for 17 states in the representation 2S+lA(±)via CASSCF method. Multirefere...The potential energy curves of the molecule CdS have been calculated for 245 internuclear distances in the range 2.15 A 〈 r ≤6.471 A for 17 states in the representation 2S+lA(±)via CASSCF method. Multireference CI calculations (single and double excitations with Davidson corrections) were performed by using Gaussian basis sets for the two considered atoms. The potential energy curves, the harmonic frequency ωe, the internuclear distance re, the rotational constant Be, the electronic energy with respect to the ground state Te and the static dipole moment have been calculated. The comparison of these values to the available data in the literature shows a good agreement. To the best of our knowledge, eleven electronic states have been investigated here for the first time.展开更多
Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength (TS in dB re l m^2...Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength (TS in dB re l m^2) with the different body size to accurately estimate ice krill stocks. However, there is comparatively little knowledge of the acoustic backscatter of ice krill. The TS of individual, formalin-preserved, tethered ice krill was measured in a freshwater test tank at 38, 120, and 200 kHz with a calibrated split-beam echo sounder system. Mean TS was obtained from 21 individual ice krill with a broad range of body lengths (L: 13-36 iron). The length (L, mm) to wet weight (W; mg) relationship for ice krill was 11/=0.001 21g^103~L35s (R2=0.96). The mean TS-to-length relationship were TS38kHz=-177.4+57log10(L), (R^2=0.86); TS120kHz= -129.9+31.561ogf0(L), (R2=0.87); and TS200kHz=-117.6+24.661ogre(L), (R2=0.84). Empirical estimates of the relationship between the TS and body length of ice krill were established at 38, 120, and 200 kHz and compared with predictions obtained from both the linear regression model of Greene et al. (1991) and the Stochastic Distorted Wave Born Approximation (SDWBA) model. This result might be applied to improve acoustic detection and density estimation of ice krill in the Southern Ocean. Further comparative studies are needed with in situ target strength including various body lengths of ice krill.展开更多
The cooperation effects of GA3, IAA and uniconazole-P were studied on the gravitropism and wood formation in Fraxinus mandshurica Rupr. var.japonica Maxim. Seedlings using traditional paraffin section technology. Our ...The cooperation effects of GA3, IAA and uniconazole-P were studied on the gravitropism and wood formation in Fraxinus mandshurica Rupr. var.japonica Maxim. Seedlings using traditional paraffin section technology. Our results are: (1) Gravitropism of stems was strongly inhibited only in B, whereas promoted significantly in D, E, F, H and I treatments; (2) Xylem formation was increased on both sides in H, I and J treatments and on the lower side in E and F which also show the synergistic effect; (3) On the radial direction, cell wall thickness was enhanced on the upper side, whereas decreased on the lower side in C, and was also significantly promoted on the upper in E, G, H, I and J treatments. On the tangential direction, cell wall thickness was increased on the lower side in E, H, I and J treatments respectively; (4) Gelatinous layer of wood fibers was observed on the upper side in all treatments. These results suggest that both GA3 and IAA affected negative gravitropism and wood formation significantly. However, appliedor unapplited-uniconazole-P does not affect G-layer formation, indicating GA does not play the key role on G-layer formation, and ratio of GA3/IAA or IAA may be more important in regulating G-layer formation.展开更多
The paper presents a Monte Carlo simulation to study the adsorption characteristics of methane molecule on coal slit pores from different aspects.Firstly,a physical model of adsorption and desorption of methane molecu...The paper presents a Monte Carlo simulation to study the adsorption characteristics of methane molecule on coal slit pores from different aspects.Firstly,a physical model of adsorption and desorption of methane molecules on micropores was established.Secondly,a grand canonical ensemble was introduced as the Monte Carlo simulation system.Thirdly,based on the model and system,the molecule simulation program was developed with VC++6.0 to simulate the isothermal adsorption relationship between the amount of molecule absorption and the factors affecting it.Lastly,the numerically simulated results were compared with measured results of adsorption coal samples of two different coal mines with a laboratory gas absorption instrument.The results show that the molecule simulations of the adsorption constants,the adsorption quantity,and the isothermal adsorption curve at the same and different coal temperatures were in good agreement with those measured in the experiments,indicating that it is feasible to use the established model and the Monte Carlo molecule simulation to study the adsorption characteristics of methane molecules in coal.展开更多
On the basis of the historical statistics on power consumption, this paper anal)yes the power consumption trends in China by means of analyzing methods based on consumption proportion curve, fixed base curve, month-o...On the basis of the historical statistics on power consumption, this paper anal)yes the power consumption trends in China by means of analyzing methods based on consumption proportion curve, fixed base curve, month-on-month increase curve and fixed base index curve. Special attentions are paid to the consumption trend in the first half of 2010, and policy strategies are suggested targeting the problems reflected by the consumption trend.展开更多
In order to reduce the regional differentials or narrow the gap in economic development between eastern and western areas and prevent the intensification of contradictions resulting from the regional inequality during...In order to reduce the regional differentials or narrow the gap in economic development between eastern and western areas and prevent the intensification of contradictions resulting from the regional inequality during the development process, the government of China launched the Great Campaign of Western Development (GCWD) in 2000. In this paper, we will evaluate the effects of the first 10 years' GCWD and use the latest Chinese annual data from 1978 to 2010 to investigate the problem of regional differentials in the development process, evaluate the effects of GCWD policy and test whether there is a regional Kuznets inverted-U curve in the regional development of China. The result shows that there are both good and bad news: the good news is that the inverted U-shaped curve of absolute differential between eastern and western areas finally emerges (the previous studies showed that the inverted-U curve did not appear and the differentials between eastern and western areas became worse) and the bad news is that the differential is in the first half of the inverted U-shaped curve in our choice of time span (1978-2010), that is, it is still in the situation of deterioration, and the turning better point will emerge in 2025. Although the western areas have benefitted from GCWD, the absolute gap has been still widened. To narrow the gap, the western areas should accelerate the industrial development and the government should adjust the policy and make more efforts to support the development of the industry in the western areas, especially cultivate and support the development of the western characteristic and advantageous industry rather than just supporting the construction of infrastructure in the western areas.展开更多
This article describes a study of the satellite module layout problem (SMLP), which is a three-dimensional (3D) layout optimization problem with performance constraints that has proved to be non-deterministic poly...This article describes a study of the satellite module layout problem (SMLP), which is a three-dimensional (3D) layout optimization problem with performance constraints that has proved to be non-deterministic polynomial-time hard (NP-hard). To deal with this problem, we convert it into an unconstrained optimization problem using a quasi-physical strategy and the penalty function method. The energy landscape paving (ELP) method is a class of Monte-Carlo-based global optimization algorithm that has been successfully applied to solve many optimization problems. ELP can search for low-energy layouts via a random walk in complex energy landscapes. However, when ELP falls into the narrow and deep valleys of an energy landscape, it is difficult to escape. By putting forward a new update mechanism of the histogram function in ELP, we obtain an improved ELP method which can overcome this drawback. By incorporating the gradient method with local search into the improved ELP method, a new global search optimization method, hELP, is proposed for SMLP. Two representative instances from the literature are tested. Computational results show that the proposed hELP algorithm is an effective method for solving SMLP with performance constraints.展开更多
We verify the accuracy of the curvature-based potential.By means of the idealized numerical experiment,we show that the curvature-based potential is in good agreement with the numerical experiment,and the errors are w...We verify the accuracy of the curvature-based potential.By means of the idealized numerical experiment,we show that the curvature-based potential is in good agreement with the numerical experiment,and the errors are within a reasonable range.Based on the curvature-based potential,the equipotential surfaces of particles are derived,and the intrinsic relations between the equipotential surfaces and Weingarten helicoids are shown.展开更多
基金This work was supported by the National Natural Science Foundation of China (No.20273066).
文摘The potential energy curves of the ground state X2∑+g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees (RKR) method extrapolated by a Hulburt and Hirschfeler potential function for longer internuclear distances. Solving the corresponding radial one-dimensional Schr?dinger equation of nuclear motion yields 22 bound vibrational levels above v=0. The comparison of these theoretical levels with the experimental data yields a mean absolute deviation of about 7.6 cm^-1 over the 23 levels. The highest vibrational level energy obtained using this method is 13308.16 cm?1 and the relative deviation compared with the experimental datum of 13408.49 cm^-1 is only 0.74%. The value from our method is much closer and more accurate than the value obtained by the quantum mechanical ab initio method by Bytautas. The reported agreement of the vibrational levels and dissociation energy with experiment is contingent upon the potential energy curve of the F2 ground state.
基金Supported by the Key New Products Development Program of Science and Technology Agency of Yunnan Province(2011BB012)~~
文摘[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year:the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate (Thuab) Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants(pomegranate and E. ciliate (Thuab) Hyland) when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.
文摘A new physical current-voltage model for polysilicon thin-film transistors (poly-Si TFTs) is presented. Taking the V-shaped exponential distribution of trap states density into consideration,explicit calculation of surface potential is derived using the Lambert W function, which greatly improves computational efficiency and is critical in circuit simulation. Based on the exponential density of trap states and the calculated surface potential, the drain current characteristics of the subthreshold and the strong inversion region are predicted. A complete and unique drain current expression, including kink effect, is deduced. The model and the experimental data agree well over a wide range of channel lengths and operational regions.
文摘To investigate the buckling and post buckling behaviors of elastic thin plate under frictionless unilateral restraint, enduring the coupling action of lognitudinal and transverse loads, the principle of minimum potential energy and variational method are used and series functions with unknown coefficients are taken as trial functions of functional to solve the large deflection and non linear bending problem of a thin plate and find relation curves between deflection of plate and loads. The proposed method can capture the buckling and post buckling behaviors of a thin plate in different geometrical and load boundary conditions. The analysis confirms that there occur snap and bifurcation behaviors in the post buckling stage of the plate. And these results show the validity of the variational method for solving buckling problems of thin plate.
基金This work is supported by the National Key Basic Program of China (No.2010CB922900) and the National Natural Science Foundation of China (No.91021008, No.i1274196, and No.iiiii120061).
文摘A new 2-D variational method is proposed to calculate the vibrational energy levels of the symmetric P-H stretching vibration (vl) and the symmetric umbrella vibration (inversion vibration) (v2) of PH3^+(^~X^2A″2) that has the tunneling effect. Because the symmetric internal Cartesian coordinates were employed in the calculations, the kinetic energy operator is very simple and the inversion vibrational mode is well characterized. In comparison with the often used I-D model to calculate the inversion vibrational energy levels, this 2-D method does not require an assmnption of reduced mass, and the interactions between the vl and v2 vibrational modes are taken into consideration. The calculated vibrational energy levels of PH3^+ are the first reported 2-D calculation, and the average deviation to the experimental data is less than 3 cm^-1 for the first seven inversion vibrational energy levels. This method has also been applied to calculate the vibrational energy levels of NH3. The application to NH3 is less successful, which shows some limitations of the method compared with a full dimension computation.
基金Projects(51804136,51764016)supported by the National Natural Science Foundation of ChinaProject(U1402271)supported by the Joint Funds of the National Natural Science Foundation of China+2 种基金Project(20181BAB216017)supported by the Jiangxi Provincial Natural Science Foundation,ChinaProject(GK-201803)supported by the Research Fund Program of State Key Laboratory of Rare Metals Separation and Comprehensive Utilization,ChinaProjects(yy2016001,yy2016012)supported by the Research Fund Program of the State Key Laboratory of Pressure Hydrometallurgical Technology of Associated Nonferrous Metal Resources,China。
文摘The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.
基金the National Natural Science Foundation of China (10671165)Specialized Research Fund for the Doctoral Program of Higher Education of China (20050755001)
文摘Let G = (V, E) be a connected graph. X belong to V(G) is a vertex set. X is a 3-restricted cut of G, if G- X is not connected and every component of G- X has at least three vertices. The 3-restricted connectivity κ3(G) (in short κ3) of G is the cardinality of a minimum 3-restricted cut of G. X is called κ3-cut, if |X| = κ3. A graph G is κ3-connected, if a 3-restricted cut exists. Let G be a graph girth g ≥ 4, κ3(G) is min{d(x) + d(y) + d(z) - 4 : xyz is a 2-path of G}. It will be shown that κ3(G) = ξ3(G) under the condition of girth.
基金supported by the US National Science Foundation (grant number CHE-1566636)UC MEXUS-CONACYT Collaborative Grant (CN-1668)DGAPA-UNAM for support through Project PAPIIT IN-115916.
文摘Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.
文摘In this paper, the buckling behavior of zigzag BN (Boron Nitride) nanotubes under bending is studied through molecular dynamics finite element method with Tersoff potential. The tube with namely (15, 0) BN zigzag tube is investigated. The critical bending buckling angle, moment and curvature are studied and examined with respect to the tube length-diameter ratios from 5 to 30. Effects of a SW (Stone-Wales) defect in the middle tube on the bending behavior are also discussed. The results show that the tube length affects significantly the bending behavior of these tubes. All tubes exhibit brittle fracture under bending. The buckling takes place at the middle in the compressive side of these tubes. These results are important information on the buckling behaviors of pristine and Stone-Wales BN nanotubes, which will be useful for their future applications.
基金supported by the National Key Research and Development Program of China(No.2017YFA0304900,No.2017YFA0402300,and No.2016YFA0300600)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB28000000 and No.XDB07030000)+2 种基金the National Natural Science Foundation of China(No.11604334,No.11575099 and No.11474347)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(No.KF201807)the Science Challenge Project(No.TZ2016005)
文摘We performed high-level ab initio calculations on electronic structure of Na K. The potential energy curves (PECs) of 10 Λ-S states correlated with the three lowest dissociation limits have been calculated. On the basis of the calculated PECs, the spectroscopic constants of the boundΛ-S states are obtained, which are in good agreement with experimental results. The maximum vibrational quantum numbers of the singlet ground state X^1Σ^+ and the triplet ground state a^3Σ^+ have been analyzed with the semiclassical scattering theory. Transition properties including transition dipole moments, Franck-Condon factors, and radiative lifetimes have been investigated. The research results indicate that such calculations can provide fairly reliable estimation of parameters for the ultracold alkali diatomic molecular experiment.
基金Supported by National Natural Science Foundation of China under Grant Nos. 10735010, 10975072, and 11035001, by 973 National Major State Basic Research and Development of China under Grant No. 2007CB815004 and 2010CB327803, CAS Knowledge Innovation Project under Grant No. KJCX2-SW-N02, and by Research Fund of Doctoral Point under Grant No. 20100091110028
文摘The newly synthesized element 117 and its alpha-decay chains are systematically investigated in the framework of the relativistic mean field theory with parameter sets NL-Z2 and TMA. The ground-state properties of the superheavy nuclei on the alpha-decay chains of 294 117 and 293 117 are calculated. The experimental alpha-decay energies and ha Jr-lives of the two alpha-decay chains are reasonably reproduced by the model The detailed discussions on the binding energies, alpha-decay energies, half-lives, quadrupole deformations, potential energy curves, and single particle levels of the two alpha-decay chains are made.
文摘The potential energy curves of the molecule CdS have been calculated for 245 internuclear distances in the range 2.15 A 〈 r ≤6.471 A for 17 states in the representation 2S+lA(±)via CASSCF method. Multireference CI calculations (single and double excitations with Davidson corrections) were performed by using Gaussian basis sets for the two considered atoms. The potential energy curves, the harmonic frequency ωe, the internuclear distance re, the rotational constant Be, the electronic energy with respect to the ground state Te and the static dipole moment have been calculated. The comparison of these values to the available data in the literature shows a good agreement. To the best of our knowledge, eleven electronic states have been investigated here for the first time.
基金Supported by the Korea Polar Research Institute(No.PP14020)the Korea Institute of Ocean Science and Technology(No.PN65250)
文摘Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength (TS in dB re l m^2) with the different body size to accurately estimate ice krill stocks. However, there is comparatively little knowledge of the acoustic backscatter of ice krill. The TS of individual, formalin-preserved, tethered ice krill was measured in a freshwater test tank at 38, 120, and 200 kHz with a calibrated split-beam echo sounder system. Mean TS was obtained from 21 individual ice krill with a broad range of body lengths (L: 13-36 iron). The length (L, mm) to wet weight (W; mg) relationship for ice krill was 11/=0.001 21g^103~L35s (R2=0.96). The mean TS-to-length relationship were TS38kHz=-177.4+57log10(L), (R^2=0.86); TS120kHz= -129.9+31.561ogf0(L), (R2=0.87); and TS200kHz=-117.6+24.661ogre(L), (R2=0.84). Empirical estimates of the relationship between the TS and body length of ice krill were established at 38, 120, and 200 kHz and compared with predictions obtained from both the linear regression model of Greene et al. (1991) and the Stochastic Distorted Wave Born Approximation (SDWBA) model. This result might be applied to improve acoustic detection and density estimation of ice krill in the Southern Ocean. Further comparative studies are needed with in situ target strength including various body lengths of ice krill.
基金This research was supported by the scholarship from the Japanese Ministry of Education (No. 07456073), Scientific Research Foundation for the Returned Oversea Chinese Scholars, State Education Ministry of China, Natural Science Foundation of Tianjin, China (No. 07JCYBJCI2400 and No. 07JCYBJCI2500) and National Key Basic Research Plan Proiect (No. 2007CB 106802).
文摘The cooperation effects of GA3, IAA and uniconazole-P were studied on the gravitropism and wood formation in Fraxinus mandshurica Rupr. var.japonica Maxim. Seedlings using traditional paraffin section technology. Our results are: (1) Gravitropism of stems was strongly inhibited only in B, whereas promoted significantly in D, E, F, H and I treatments; (2) Xylem formation was increased on both sides in H, I and J treatments and on the lower side in E and F which also show the synergistic effect; (3) On the radial direction, cell wall thickness was enhanced on the upper side, whereas decreased on the lower side in C, and was also significantly promoted on the upper in E, G, H, I and J treatments. On the tangential direction, cell wall thickness was increased on the lower side in E, H, I and J treatments respectively; (4) Gelatinous layer of wood fibers was observed on the upper side in all treatments. These results suggest that both GA3 and IAA affected negative gravitropism and wood formation significantly. However, appliedor unapplited-uniconazole-P does not affect G-layer formation, indicating GA does not play the key role on G-layer formation, and ratio of GA3/IAA or IAA may be more important in regulating G-layer formation.
基金supported by the Industrial Research Project in Guizhou Science and Technology Bureau of China (GY(2011)No.3012)International Cooperation Projects in Guizhou Science and Technology Bureau of China (G(2009)No.700111)
文摘The paper presents a Monte Carlo simulation to study the adsorption characteristics of methane molecule on coal slit pores from different aspects.Firstly,a physical model of adsorption and desorption of methane molecules on micropores was established.Secondly,a grand canonical ensemble was introduced as the Monte Carlo simulation system.Thirdly,based on the model and system,the molecule simulation program was developed with VC++6.0 to simulate the isothermal adsorption relationship between the amount of molecule absorption and the factors affecting it.Lastly,the numerically simulated results were compared with measured results of adsorption coal samples of two different coal mines with a laboratory gas absorption instrument.The results show that the molecule simulations of the adsorption constants,the adsorption quantity,and the isothermal adsorption curve at the same and different coal temperatures were in good agreement with those measured in the experiments,indicating that it is feasible to use the established model and the Monte Carlo molecule simulation to study the adsorption characteristics of methane molecules in coal.
文摘On the basis of the historical statistics on power consumption, this paper anal)yes the power consumption trends in China by means of analyzing methods based on consumption proportion curve, fixed base curve, month-on-month increase curve and fixed base index curve. Special attentions are paid to the consumption trend in the first half of 2010, and policy strategies are suggested targeting the problems reflected by the consumption trend.
文摘In order to reduce the regional differentials or narrow the gap in economic development between eastern and western areas and prevent the intensification of contradictions resulting from the regional inequality during the development process, the government of China launched the Great Campaign of Western Development (GCWD) in 2000. In this paper, we will evaluate the effects of the first 10 years' GCWD and use the latest Chinese annual data from 1978 to 2010 to investigate the problem of regional differentials in the development process, evaluate the effects of GCWD policy and test whether there is a regional Kuznets inverted-U curve in the regional development of China. The result shows that there are both good and bad news: the good news is that the inverted U-shaped curve of absolute differential between eastern and western areas finally emerges (the previous studies showed that the inverted-U curve did not appear and the differentials between eastern and western areas became worse) and the bad news is that the differential is in the first half of the inverted U-shaped curve in our choice of time span (1978-2010), that is, it is still in the situation of deterioration, and the turning better point will emerge in 2025. Although the western areas have benefitted from GCWD, the absolute gap has been still widened. To narrow the gap, the western areas should accelerate the industrial development and the government should adjust the policy and make more efforts to support the development of the industry in the western areas, especially cultivate and support the development of the western characteristic and advantageous industry rather than just supporting the construction of infrastructure in the western areas.
基金Project supported by the National Natural Science Foundation of China (No. 61373016), the Six Talent Peaks Project of Jiangsu Province, China (No. DZXX-041), the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Natural Science Foundation of Jiangsu Province, China (No. BK20141005)
文摘This article describes a study of the satellite module layout problem (SMLP), which is a three-dimensional (3D) layout optimization problem with performance constraints that has proved to be non-deterministic polynomial-time hard (NP-hard). To deal with this problem, we convert it into an unconstrained optimization problem using a quasi-physical strategy and the penalty function method. The energy landscape paving (ELP) method is a class of Monte-Carlo-based global optimization algorithm that has been successfully applied to solve many optimization problems. ELP can search for low-energy layouts via a random walk in complex energy landscapes. However, when ELP falls into the narrow and deep valleys of an energy landscape, it is difficult to escape. By putting forward a new update mechanism of the histogram function in ELP, we obtain an improved ELP method which can overcome this drawback. By incorporating the gradient method with local search into the improved ELP method, a new global search optimization method, hELP, is proposed for SMLP. Two representative instances from the literature are tested. Computational results show that the proposed hELP algorithm is an effective method for solving SMLP with performance constraints.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11072125 and 10872114)the Natural Science Foundation of Jiangsu Province (Grant No. SBK201140044)
文摘We verify the accuracy of the curvature-based potential.By means of the idealized numerical experiment,we show that the curvature-based potential is in good agreement with the numerical experiment,and the errors are within a reasonable range.Based on the curvature-based potential,the equipotential surfaces of particles are derived,and the intrinsic relations between the equipotential surfaces and Weingarten helicoids are shown.