关于复合力势能表达式的讨论

本文指出了"关于惯性力场的讨论"一文中的不妥之处,根据势能叠加原理,给出了复合力势能的另一种表达式。

当今中国大陆地壳移动的动力

地幔圈形状周期性变化使地壳产生势能 (位能 )力导致地壳运动。当地幔圈由圆相对变扁 ,南、北半球的高纬度区地壳向低纬度区对挤 ;当地幔圈由扁相对变圆 ,恢复等位面平衡 ,南、北半球低纬度区的地壳区分别向高纬度区挤压。当今中国大陆地壳移动的动力是由于西部地区的地幔还在继续进行恢复等位面平衡产生的。

朋友圈交际联接与女性农民追逐百元经济——基于产业链就业共同体的中介效应研究

在现代化发展引领下,乡村社会传统生产生活共同体的同质状态逐步被职业分工的异质社会所替代,女性农民冲破家庭和社会约束,实现着个体的“她力量”自信和经济独立性偏好。基于特色农产品产业链务工女性农民的调研数据,建立起朋友圈交际联接、产业链就业共同体与女性农民追逐百元经济间的中介效应模型,研究结果表明:(1)朋友圈交际联接对女性农民追逐百元经济具有显著促进作用,从我国东部、中部、西部分布看,其作用关系在不同区域间表现出明显的差异性,且梯级递进。(2)产业链就业共同体在朋友圈交际联接与女性农民追逐百元经济间发挥部分中介效应。(3)自信和经济方面谋求独立的女性农民更偏向追逐较高的经济收入;家庭内生性货币需求压力促进女性农民追逐百元经济的积极性逐渐减弱;产业下沉对产业链就业共同体影响下的女性农民追逐百元经济产生抑制作用。

一种基于聚类的虚拟计算环境资源聚合方法

作为面向互联网资源共享的虚拟计算环境的实例,iVCE(Internet based virtual computing environment)for Memory致力于解决广域分布的内存资源的共享与综合利用问题.由于内存资源的特殊性,传统的资源管理方法很难适用.以iVCE for Memory作为背景,提出一种基于聚类的虚拟计算环境资源聚合方法,有效降低了资源聚合的问题规模;借鉴物理学中的力场和势能理论,建立了实现资源聚合的基本模型和力场-势能模型以及相应的分布式算法;通过基于真实网络拓扑的模拟,对两种模型和算法分别进行了评估和验证.

A method based on potential theory for calculating air ca formation of an air cavity resistance reduction ship

This research is intended to provide academic reference and design guidance for further studies to determine the most effective means to reduce a ship’s resistance through an air-cavity. On the basis of potential theory and on the assumption of an ideal and irrotational fluid, this paper drives a method for calculating air cavity formation using slender ship theory then points out the parameters directly related to the formation of air cavities and their interrelationships. Simulations showed that the formation of an air cavity is affected by cavitation number, velocity, groove geometry and groove size. When the ship’s velocity and groove structure are given, the cavitation number must be within range to form a steady air cavity. The interface between air and water forms a wave shape and could be adjusted by an air injection system.

High-precision gravity correction methods for loess plateau areas, a case study

The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast with the underlying formation, a high frequency gravity anomaly with a certain magnitude will appear. The high frequency gravity anomaly can result in some difficulties for processing and interpreting the gravity data, thereby reducing the usefulness of gravity surveys in loess plateau areas. We carried out a high precision gravity survey in the SHJZ structural zone. During data processing, we applied terrain and loess corrections to effectively remove or suppress the gravity effect resulting from surface undulation and variation of loess thickness. We obtained high precision gravity data which matches well with other geophysical data. The comprehensive interpretation based on the final gravity data help to study local structure integrated with other published geophysical data.

A Quantum Wavepacket Study of State-to-State Photodissociation Dynamics of HOBr/DOBr

Photodissociation of HOBr is an important step in the reaction network of the depletion of ozone in stratosphere.Here,we report the first three-dimensional potential energy surfaces for the lowest three singlet states for HOBr,based on high level multi reference configuration interaction calculations.Quantum dynamics calculations are performed with a real wavepacket method,yielding not only absorption spectra but also internal state and angular distributions of the photodissociation fragments.Our results agree quantitatively with the measured total absorption cross sections of HOBr in the ultraviolet region and reproduce well the observed vibrationally cold and rotationally hot OH/OD fragments via photodissociation of HOBr/DOBr at 266 nm.In addition,we predict that the recoil anisotropy parameters for OH/OD are close to the limiting value of a parallel transition,suggesting a rapid dissociation process at 266 nm following an in-plane transition from the ground state(1^1A')to the 21A'state.This is consistent with the experimental conclusion derived from the measured rotational alignment.However,spin and electronic angular momenta need to be taken into account in the future to achieve a more quantitative agreement with experiment.Our work is expected to motivate further experimental investigations for this benchmark system.

由做功公式引发的思索

我们可以把物体所受到的重力及电荷在匀强电场中的电场力等作为特例都纳入此恒力系统来研究问题,从而得出一般性结论:在只有恒力做功的情况下,物体的动能与恒力势能可以相互转化,但转化过程中能量的总和不变。首先通过证明恒力做功与路径无关,从而引入类保守力,通过类比引入恒力势能,进而把重力做功、电场力做功等与之相联系的重力势能及电势能也纳入此系列,最终将能量守恒定律进一步推广到一般;同时也为物理学关于功与能的关系作一更深入探索。

Using the surface panel method to predict the steady performance of ducted propellers

A new numerical method was developed for predicting the steady hydrodynamic performance of ducted propellers. A potential based surface panel method was applied both to the duct and the propeller, and the interaction between them was solved by an induced velocity potential iterative method. Compared with the induced velocity iterative method, the method presented can save programming and calculating time. Numerical results for a JD simplified ducted propeller series showed that the method presented is effective for predicting the steady hydrodynamic performance of ducted propellers.

Dynamic Behavior and Quasi—energy Spectrum of Multiband Superlattice Bloch Electrons in Quantum Kicked Potential

In this paper, we study the dynamic behavior and quasi-energy spectrum of multiband superlattice Bloch electrons in quantum kicked potential. We show analytically and numerically the avoided crossing and band suppression about the quasi-energy spectrum, the dynamic nonlocalization, and the electron oscillation behavior between two bands.

Structures and Dynamics of a Two-Dimensional Confined Dusty Plasma System

The influence of the confining potential strength and temperature on the structures and dynamics of a two-dimensional (2D) dusty plasma system is investigated through molecular dynamic (MD) simulation. The circular symmetric confining potential leads to the nonuniform packing of particles, that is, an inner core with a hexagon lattice surrounded by a few outer circular shells. Under the appropriate confining potential and temperature, the particle trajectories on middle shells form a series of concentric and nested hexagons due to tangential movements of particles.Mean square displacement, self-diffusion constant, pair correlation function, and the nearest bond are used to characterize the structural and dynamical properties of the system. With the increase of the confining potential, the radial and tangential movements of particles have different behaviors. With the increase of temperature, the radial and tangential motions strengthen, particle trajectories gradually become disordered, and the system gradually changes from a crystal or liquid state to a gas state.

Molecular Thermodynamics of Charged Hard-Dumbbell Fluids

Chemical potentials of charged hard-dumbbell fluids are obtained by Monte Carlo simulations using Widom's test-particle method, corresponding compressibility factors are achieved by integration of chemical potentials at different densities. A molecular thermodynamic model is also developed for these charged hard-dumbbell fluids where the residual Helmholtz function is composed of two terms: a reference term responsible for the charged hard spheres and a bonding contribution measuring the sticky interactions between positive and negative hard ions.Model predictions are in good agreement with simulation results.

Quantitative Description of Potential of Mean Force Between Macroparticles in Fluid with Attactive Forces

A statistical mechanics method is proposed for calculation of potential ofmean force (PMF). In the case of solvophobic or solvophilic macroparticles immersed in solvent bathof soft sphere or Lennard-Jones particles, prediction accuracy for the PMF and MF from the simplestimplementation of the proposed method, where hypernetted chain approximation is adopted forcorrelation of the macroparticle-macroparticle at infinitely dilute limit, is comparable to that ofa recent more sophisticated approach based on mixture Ornstein—Zernike integral equation / bridgefunction from fundamental measure functional. Adaptation of the present method for general complexQuids is discussed, and method for improving the accuracy is suggested. Differences and relativemerits of the present recipe compared with that based on potential distribution theory is discussed.

Characteristics of soil enzymes and the dominant species of repair trees in the reclamation of coal mine area

In order to study the soil enzyme content at the mine reclamation area and choose a tree species with superior restoration capabilities, this paper takes Huainan Datong Mine as the study area, and five different enzymes under nine tree species as the study subject. The different enzyme activity indexes were measured, and the correlation analysis and the principal component analysis （PCA） method were applied to evaluate and screen the tree species with advanced restoration. The results demonstrate that there are some correlations among the different soil enzymes, including some very significant positive correlations among urease, phosphatase, invertase and protease. The best species in terms of repair is privet, and the worst is Haltong. This study provides a scientific basis for the selection of restoration-capable tree species in the reclamation area of the coal mine.

Revised Iterative Solution of Ground State of Double-Well Potential

The revised new iterative method for solving the ground state of Schroedingerequation is deduced. Based on Green functions defined by quadratures along a single trajectory thisiterative method is applied to solve the ground state of the double-well potential. The result iscompared to the one based on the original iterative method. The limitation of the asymptoticexpansion is also discussed.

Quantum Dynamics of Oxyhydrogen Complex-Forming Reactions for the HO2 and HO3 Systems

Complex-forming reactions widely exist in gas-phase chemical reactions. Various complexforming bimolecular reactions have been investigated and interesting phenomena have been discovered. The complex-forming reactions usually have small or no barrier in the entrance channel, which leads to obvious differences in kinetic and dynamic characteristics compared with direct reactions. Theoretically, quantum state-resolved reaction dynamics can provide the most detailed microscopic dynamic mechanisms and is now feasible for a direct reaction with only one potential barrier. However, it is of great challenge to construct accurate potential energy surfaces and perform accurate quantum dynamics calculations for a complex polyatomic reaction involving deep potential wells and multi-channels. This paper reviews the most recent progress in two prototypical oxyhydrogen complex-forming reaction systems, HO2 and HO3, which are significant in combustion, atmospheric, and interstellar chemistry. We will present a brief survey of both computational and experimental work and emphasize on some unsolved problems existing in these systems.

EOM-CCSD-Based Neural Network Diabatic Potential Energy Matrix for ^(1)πσ^(*)-Mediated Photodissociation of Thiophenol

A new diabatic potential energy matrix(PEM)of the coupled~^(1)ππ^(*)and~1πσ*states for the~1πσ*-mediated photodissociation of thiophenol was constructed using a neural network(NN)approach.The diabatization of the PEM was specifically achieved by our recent method[Chin.J.Chem.Phys.34,825(2021)],which was based on adiabatic energies without the associated costly derivative couplings.The equation of motion coupled cluster with single and double excitations(EOM-CCSD)method was employed to compute adiabatic energies of two excited states in this work due to its high accuracy,simplicity,and efficiency.The PEM includes three dimensionalities,namely the S-H stretch,C-S-H bend,and C-C-S-H torsional coordinates.The root mean square errors of the NN fitting for the S1 and S2 states are 0.89 and 1.33 me V,respectively,suggesting the high accuracy of the NN method as expected.The calculated lifetimes of the S1 vibronic 00 and31 states are found to be in reasonably good agreement with available theoretical and experimental results,which validates the new EOM-CCSD-based PEM fitted by the NN approach.The combination of the diabatization scheme solely based on the adiabatic energies and the use of EOM-CCSD method makes the construction of reliable diabatic PEM quite simple and efficient.

量子化学模型方法在机械力化学中的应用

机械力化学作为一种无需溶剂的绿色化学技术得到广泛关注。然而,机械力化学反应机制需要从原子和分子尺度上深入理解力诱导的化学反应。在过去的20年中,量子化学模型方法在机械力化学机理研究中得到广泛应用,高精度量化计算可得到外力下变形分子的几何结构、能量、过渡态等诸多性质。本文介绍了目前机械力化学领域的主流量子化学模型的基本原理,同时也关注了这些模型方法在软件上的具体实现,并借助典型的案例阐述了量子化学模型在解释机械力化学机理中的作用与价值。

Quasi-Classical Trajectory Investigation of H+SO_(2)→OH+SO Reaction on Full-Dimensional Accurate Potential Energy Surface

The reaction H+SO_(2)→OH+SO is important in the combustion and atmospheric chemistry,as well as the interstellar medium.It also represents a typical complex-forming reaction with deep complexes,serving as an ideal candidate for testing various kinetics theories and providing interesting reaction dynamical phenomena.In this work,we reported a quasiclassical trajectory study of this reaction on our previously developed accurate full-dimensional potential energy surface.The experimental thermal rate coefficients over the temperature range 1400 K≤T≤2200 K were well reproduced.For the reactant SO_(2)being sampled at the ground ro-vibrational state,the calculated integral cross sections increased slightly along the collision energy ranging from 31.0 kcal/mol to 40.0 kcal/mol,and then became essentially flat at the collision energy within 40.0−55.0 kcal/mol.The product angular distributions are almost symmetric with nearly identical backward-forward double peak structure.The products OH and SO vibrational state distributions were also analyzed.

Effects of core and non-dominant arm strength training on drive distance in elite golfers

Background： Various training schemes have sought to improve golf-related athletic ability. In the golf swing motion, the muscle strengths of the core and arms play important roles, where a difference typically exists in the power of arm muscles between the dominant and non- dominant sides. The purposes of this study were to determine the effects of exercises strengthening the core and non-dominant arm muscles of elite golf players （handicap 〈 3） on the increase in drive distance, and to present a corresponding training scheme aimed at improving golf performance ability. Methods： Sixty elite golfers were randomized into the control group （CG, n = 20）, core exercise group （CEG, n = 20）, and group receiving a combination of muscle strengthening exercises of the non-dominant arm and the core （NCEG, n = 20）. The 3 groups conducted the corresponding exercises for 8 weeks, after which the changes in drive distances and isokinetic strength were measured. Results： Significant differences in the overall improvement of drive distance were observed among the groups （p 〈 0.001）. Enhancement of the drive distance of NCEG was greater than both CG （p 〈 0.001） and CEG （p = 0.001）. Except for trunk flexion, all variables of the measurements of isokinetic strength for NCEG also showed the highest values compared to the other groups. Examination of the correlation between drive distance and isokinetic strength revealed significant correlations of all variables except trunk flexion, wrist extension, and elbow extension. Conclusion： The combination of core and non-dominant arm strength exercises can provide a more effective specialized training program than core alone training for golfers to increase their drive distances.