UML-based combat effectiveness simulation system modeling within MDE

To reduce complexity, the combat effectiveness simulation system(CESS) is often decomposed into static structure,physical behavior, and cognitive behavior, and model abstraction is layered onto domain invariant knowledge(DIK) and application variant knowledge(AVK) levels. This study concentrates on the specification of CESS’s physical behaviors at the DIK level of abstraction, and proposes a model driven framework for efficiently developing simulation models within model-driven engineering(MDE). Technically, this framework integrates the four-layer metamodeling architecture and a set of model transformation techniques with the objective of reducing model heterogeneity and enhancing model continuity. As a proof of concept, a torpedo example is illustrated to explain how physical models are developed following the proposed framework. Finally, a combat scenario is constructed to demonstrate the availability, and a further verification is shown by a reasonable agreement between simulation results and field observations.

Model architecture-oriented combat system effectiveness simulation based on MDE

Combat system effectiveness simulation (CSES) is a special type of complex system simulation. Three non-functional requirements (NFRs), i.e. model composability, domain specific modeling, and model evolvability, are gaining higher priority from CSES users when evaluating different modeling methodologies for CSES. Traditional CSES modeling methodologies are either domain-neutral (lack of domain characteristics consideration and limited support for model composability) or domain-oriented (lack of openness and evolvability) and fall short of the three NFRs. Inspired by the concept of architecture in systems engineering and software engineering fields, we extend it into a concept of model architecture for complex simulation systems, and propose a model architecture-oriented modeling methodology in which the model architecture plays a central role in achieving the three NFRs. Various model-driven engineering (MDE) approaches and technologies, including simulation modeling platform (SMP), unified modeling language (UML), domain specific modeling (DSM), eclipse modeling framework (EMF), graphical modeling framework (GMF), and so forth, are applied where possible in representing the CSES model architecture and its components' behaviors from physical and cognitive domain aspects. A prototype CSES system, called weapon effectiveness simulation system (WESS), and a non-trivial air-combat simulation example are presented to demonstrate the methodology.

Atomistic Simulations of the Effect of Helium on the Dissociation of Screw Dislocations in Nickel

The interactions of He with dissociated screw dislocations in face-centered-cubic （fcc） Ni are investigated by using molecular dynamics simulations based on an embedded-atom method model. The binding and formation energies of interstitial He in and near Shockley partial cores are calculated. The results show that interstitial He atoms at tetrahedral sites in the perfect fee lattice and atoms occupying sites one plane above or below one of the two Shockley partial cores exhibit the strongest binding energy. The attractive or repulsive nature of the interaction between interstitial He and the screw dislocation depends on the relative position of He to these strong binding sites. In addition, the effect of He on the dissociation of screw dislocations are investigated. It is found that Fie atoms homogeneously distributed in the glide plane can reduce the stacking fault width.

Simulation of Isotopic Angular Effects under Ion Bombardment of a^(92)Mo-^(100)Mo Target

Under 5 keV Ar ion bombardment of a 92Mo-100Mo target, we have investigated isotopic angular effects by means of the static and the dynamic Monte Carlo programs. Our calculated results are in quantitative agreement with the measured and other calculated results. The conclusion consistences among theories. simulations and measurements are also discussed.

Numerical simulation of tumor angiogenesis under the effect of Endostatin:considering mechanical environment in matrix and inhibiting effect of anti-angiogenic factor

To investigate tumor angiogenesis under the influence of Endostatin,mathematical modeling and numerical simulation of tumor angiogenesis are performed,with the mechanical environment in matrix,the inhibiting effects of Angiostatin and Endostatin into consideration.The

Ligand Size Effect on PdLn Oxidative Addition with Aryl Bromide： A DFT Study

The process and mechanism of the ligand volume controlled Pd（PR3）2 （PR3=PH3, PMe3, and PtBu3） oxidative addition with aryl bromide were investigated, using density functional theory method with the conductor-like screening model. Association pathway and dissocia-tion pathway were investigated by the comparison of several energies. The cleavage energy of Pd（PR3）2 complex was calculated, as well as the oxidative addition reaction barrier energy of Pd（PR3）n （n=1,2） with aryl bromide in N,N-dimethylformamide solvent. This study proved that the ligands volume possessed a great impact on the mechanism of oxidative addition： less bulky ligand palladium associated with aryl bromide via two donor ligands,but larger bulky ligand palladium coordinated via monoligand.

Numerical simulation to evaluate gas diffusion of turbulent flow in mine ventilation system

Tracer gas technique is a method to analyze the airflow path, measure the airflow quantity, and detect any recirculation or leakages in underground mine. In addition, it is also possible to evaluate the axial gas diffusion of gas in turbulent bulk flow by utilizing the tracer gas data. This paper discussed about the measurement using tracer gas technique in Cibaliung Underground Mine, Indonesia and the evaluation of effective axial diffusion coefficient, E, by numerical simulation. In addition, a scheme to treat network flow in mine ventilation system was also proposed. The effective axial diffusion coefficient for each airway was evaluated based on Taylor's theoretical equation. It is found that the evaluated diffusion coefficient agrees well with Taylor's equation by considering that the wall friction factor, f, is higher than those for smooth pipe flow. It also shows that the value of effective diffusion coefficient can be inherently determined and the value is constant when matching with other measurements. Furthermore, there are possibilities to utilize the tracer gas measurement data to evaluate the airway friction factors.

Protective Effects of Common Masks against PM2.5

By using two PM2.5 automatic monitors,the protective effects of five common masks against PM2.5 were synchronously tested under actual ambient air conditions for a whole day. The results showed that not all masks had protective effects on PM2.5,and the protective effects of masks N95 and N90,which were designed specially for dust-proof,were superior among the five tested masks.

High temperature effects in moving shock reflection with protruding Mach stem

The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat caoacitv, all tend to escalate the orotrusion effect.

Effects of Microgravity on Human Physiology and Ground-Based Models for Space Physiological Studies

With the development of manned spaceflight, more and more researches are involved in the area of gravitation physiology. When astronauts are exposed to microgravity, a series of special physiological or pathological changes will occur, which will start self-regulation mechanisms to reduce abnormalities and help the organism to better adapt to microgravity. However, these adaptive changes may also induce degradation or damage to physiological functions. This paper summarizes the physiological effects of microgravity on the human body from the aspects of skeletal and mineral metabolism, muscle structure and function, vestibular functions, cardiovascular function and pulmonary function, as well as expounds some commonly used ground-based space analogies. The paper will provide a reference for further study on the physiological effects of microgravity.

Collective Movement Simulation:Methods and Applications

Collective movement simulations are challenging and important in many areas,including life science,mathematics,physics,information science and public safety.In this survey,we provide a comprehensive review of the state-of-the-art techniques for collective movement simulations.We start with a discussion on certain concepts to help beginners understand it more systematically.Then,we analyze the intelligence among different collective objects and the emphasis in different fields.Next,we classify existing collective movement simulation methods into four categories according to their effects,namely versatility,accuracy,dynamic adaptability,and assessment feedback capability.Furthermore,we introduce five applications of layout optimization,emergency control,dispatching,unmanned systems,and other derivative applications.Finally,we summarize possible future research directions.

Diagenesis of the Triassic Yanchang Formation Tight Sandstone Reservoir in the Xifeng–Ansai Area of Ordos Basin and its Porosity Evolution

This work aims to reveal the evolution of the porosity in the Triassic Yanchang Formation tight sandstone reservoir of the Xifeng-Ansai area of Ordos Basin. Based on destructive diagenesis （compaction and cementation） and constructive diagenesis （dissolution） of sandstone reservoirs, this study analyzed the diagenesis characteristics of the tight sandstone reservoirs in this area, and discussed the relationship between sandstone diagenesis and porosity evolution in combination with present porosity profile characteristics of sandstone reservoir. The effect simulation principle was employed for the mathematical derivation and simulation of the evolution of porosity in the Yanchang Formation tight sandstone reservoirs. The result shows that compaction always occurs in tight sandstone reservoirs in the Yanchang Formation, and cementation occurs when the burial depth increases to a certain value and remains ever since. Dissolution occurs only at a certain stage of the evolution with window features. In the corresponding present porosity profile, diagenesis is characterized by segmentation. From the shallow to the deep, compaction, compaction, cementation and dissolution, compaction and cementation occur successively. Therefore, the evolution of sandstone porosity can be divided into normal compaction section, acidification and incremental porosity section, and normal compaction section after dissolution. The results show that the evolution of sandstone porosity can be decomposed into porosity reduction model and porosity increase model. The superposition of the two models at the same depth in the three stages or in the same geological time can constitute the evolution simulation of the total porosity in sandstone reservoirs. By simulating the evolution of sandstone reservoir porosity of the eighth member in Xifeng area and the sixth member in Ansai area, it shows that they are similar in the evolution process and trend. The difference is caused by the regional uplift or subsidence and burial depth.

Construction and stability of an extra-large section chamber in solid backfill mining

In solid backfill mining without gangue removal, the gangue is separated directly underground and backfilled into goaf. This necessitates the underground construction of an extra-large section chamber for separation equipments. For the construction of an extra-large section chamber in the Tangshan mine, we proposed an active support through a combination of bolting, anchor cables, lining, and a reinforced chamber floor by inverted arch pouring. ABAQUS software was used to analyze the surrounding rock deformation and the plastic zone development of the chamber under different excavation schemes.The best excavation scheme was determined, and the effectiveness of the combined supports was verified. In practice, the engineering installation showed good overall control of the movement of the surrounding rock, with roof-to-floor and side-to-side convergences of 154.6 and 77.5 mm, respectively,which meets the requirements for underground coal gangue separation.

Recent progress in compressible turbulence

In this paper, we review some recent studies on compressible turbulence conducted by the authors＇ group, which include fundamental studies on compressible isotropic turbulence （CIT） and applied studies on developing a con- strained large eddy simulation （CLES） for wall-bounded turbulence. In the first part, we begin with a newly pro- posed hybrid compact-weighted essentially nonoscillatory （WENO） scheme for a CIT simulation that has been used to construct a systematic database of CIT. Using this database various fundamental properties of compressible turbulence have been examined, including the statistics and scaling of compressible modes, the shocklet-turbulence interac- tion, the effect of local compressibility on small scales, the kinetic energy cascade, and some preliminary results from a Lagrangian point of view. In the second part, the idea and for- mulas of the CLES are reviewed, followed by the validations of CLES and some applications in compressible engineering problems.

Molecular dynamics simulations of temperature effect on tungsten sputtering yields under helium bombardment

Tungsten is the most promising plasma-facing material （PFM） for future nuclear fusion reactors such as international thermonuclear experimental reactor （ITER） owing to its high melting temperature, high thermal conductivity and low hydrogen retention. Under ITER-relevant conditions, a large amount of helium from the fusion reactions will constantly bombard the PFM. Though the energies of helium atoms in different regions are different,

Recent Progress of the HL-2A Multi-Channel HCOOH Laser Interferometer/Polarimeter

A multichannel methanoic acid （HCOOH, λ=432.5 μm） laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide （HCN, λ=337 μm） laser interferometer in the HL-2A tokamak. A conventional Michelson-type interometer is used for the electron density measurement, and a Dodel-Kunz-type polarimeter is used for the Faraday rotation effect measurement, respectively. Each HCOOH laser can produce a linearly polarized radiation at a power lever of -30 mW, and a power stability 〈10% in 50 rain. A beam waist （diameter d0 ≈12.0 mm, about 200 mm away from the outlet） is finally determined through a chopping modulation technique. The latest optical layout of the interferometer/polarimeter has been finished, and the hardware data processing system based on the fast Fourier transform phase- comparator technique is being explored. In order to demonstrate the feasibility of the diagnostic scheme, two associated bench simulation experiments were carried out in the laboratory, in which the plasma was simulated by a piece of polytetrafluoroethene plate, and the Faraday rotation effect was simulated by a rotating half-wave plate. Simulation results agreed well with the initial experimental conditions. At present, the HCOOH laser interferometer/polarimeter system is being assembled on HL-2A, and is planned to be applied in the 2014-2015 experimental campaign.

Simulation of quantum-well slipping effect on optical bandwidth in transistor laser

An optical bandwidth analysis of a quantum-well （16 nm） transistor laser with 150-μm cavity length using a charge control model is reported in order to modify the quantum-well location through the base region. At constant bias current, the simulation shows significant enhancement in optical bandwidth due to moving the quantum well in the direction of collector-base junction. No remarkable resonance peak, limiting factor in laser diodes, is observed during this modification in transistor laser structure. The method can be utilized for transistor laser structure design.

SIMULATION STUDY OF THE EFFECT ON COLD SURGE OF THE QINGHAI-XIZANG PLATEAU AS A HUGE OROGRAPHY

Using a limited-area P-σ incorporated coordinate five-level primitive equation model fed with the ECMWF 5°×5°grid data,a simulation is made of a large-scale cold surge of late December 1982.Results show that the Qinghai-Xizang Plateau has no profound thermal but dynamic effect on the East-Asian winter monsoon that forces cold air to go southwards by its east side,exciting Kelvin waves behind the cold front to result in the maximum NE wind.Besides,gravitational waves independent of the Plateau occur ahead of the front advancing towards the south.They may be due to the excitation involved in the front itself. The cold surge is propagated under the Hadley cell,making it strengthened and moved southwards.

Characteristics of temporal evolution of particle density and electron temperature in helicon discharge

On the basis of considering electrochemical reactions and collision relations in detail, a direct numerical simulation model of a helicon plasma discharge with three-dimensional two-fluid equations was employed to study the characteristics of the temporal evolution of particle density and electron temperature. With the assumption of weak ionization, the Maxwell equations coupled with the plasma parameters were directly solved in the whole computational domain. All of the partial differential equations were solved by the finite element solver in COMSOL Multiphysics^（TM） with a fully coupled method. In this work, the numerical cases were calculated with an Ar working medium and a Shoji-type antenna. The numerical results indicate that there exist two distinct modes of temporal evolution of the electron and ground atom density, which can be explained by the ion pumping effect. The evolution of the electron temperature is controlled by two schemes： electromagnetic wave heating and particle collision cooling. The high RF power results in a high peak electron temperature while the high gas pressure leads to a low steady temperature. In addition, an OES experiment using nine Ar I lines was conducted using a modified CR model to verify the validity of the results by simulation, showing that the trends of temporal evolution of electron density and temperature are well consistent with the numerically simulated ones.

AN EXPERIMENTAL SIMULATION ON THE MECHANICAL EFFECT OF TIBETAN PLATEAU ON ZONAL CIRCULATION OF STRATIFIED ATMOSPHERE

The present work is intended to simulate, in a rotating annulus of stratified liquid, the me-chanical effect of the Xizang (Tibetan) Plateau on the zonal circulation. The main featuresof three flow patterns around the plateau for different Rossby number R and rotating Eulernumber E are analysed. and a division diagram of the flow pattern in (R, E) plane is given.It has been found that under the condition that similarity criterions R and E of the experimentalfluid are the same as those existing in the atmosphere for monthly mean states in spring, au-tumn and winter months, the experimental results are satisfied for the following weathersystems over the plateau and its vicinities: the low vortex, trough and shear line over thesoutheast part of the plateau, the tilted ridge over the northwest part of the plateau, the troughpatterns over the upstream and dewnstream of the plateau, the vertical circulation structure, thejets on both north and southeast sides of the plateau, and so on. This shows that the mechanicaleffect of the Tibetan Plateau on the general circulation over East Asia deserves close atten-tion.