Three Dimensional Modeling of Shaft with Process Structures on CATIA

Three dimensional models of shaft were completed on CATIA Part Design module with the Chinese national standard （GB） process structures such as chamfers, threads and tool withdrawal grooves, center holes, flat/woodruff/gib head taper keyseats, grinding undercuts, straight-sidedsplines, circlip slots and collars. The modeling steps are arranged in dialog menu interface by VB 6.0, the shaft creator, that permits users input geometric feature based parameters explicitly, and the standardized processdata are reorganized in Excel files that can be invoked correspondingly in the modeling procedure. It is aimed that this process may supply a simple way for shaft rapid modeling and comprehensive discipline for engineering students in their professional design activities.

Investigation of system structure and information processing mechanism for cognitive skywave over-the-horizon radar

Based on the cognitive radar concept and the basic connotation of cognitive skywave over-the-horizon radar（SWOTHR）, the system structure and information processingmechanism about cognitive SWOTHR are researched. Amongthem, the hybrid network system architecture which is thedistributed configuration combining with the centralized cognition and its soft/hardware framework with the sense-detectionintegration are proposed, and the information processing framebased on the lens principle and its information processing flowwith receive-transmit joint adaption are designed, which buildand parse the work law for cognition and its self feedback adjustment with the lens focus model and five stages informationprocessing sequence. After that, the system simulation andthe performance analysis and comparison are provided, whichinitially proves the rationality and advantages of the proposedideas. Finally, four important development ideas of futureSWOTHR toward ＂high frequency intelligence information processing system＂ are discussed, which are scene information fusion, dynamic reconfigurable system, hierarchical and modulardesign, and sustainable development. Then the conclusion thatthe cognitive SWOTHR can cause the performance improvement is gotten.

Morphology and Structure of SiO_2 Film Using Thermal Oxidation Process on(111)Silicon Crystals in Dry Oxygen Atmosphere

By means of scanning electron microscope(SEM)and high voltage electron microscope(HVEM)we have observed and analysed morphology and micro-structure of silicon oxide film with different thickness formed on(111)silicon monocrystal under dry oxygen atmosphere at 1100℃.Compared with their oxidation kinetic curves consisted of three stages,we suggested a mechanism on forming silicon oxide film.According to electron and X-ray diffraction analyses the silicon oxide films consisted of silica with different crystal structure.We also have discussed a stacking fault and a dislocation formed in the Si-Sio_2 interface region simulaneously forming silicon oxide film.

Information Space and Information Process: Genesis and Evolution

In this article,the phenomenon of“information space”and its methods of study,its types,elementary structure and qualitative characteristics are discussed,the author’s definition of the concept of“information”is given,the structure of the information process,and the phases,which are the basis for the evolution of the information space and the universe of human activity,are considered.

Using vibrational infrared biomolecular spectroscopy to detect heat-induced changes of molecular structure in relation to nutrient availability of prairie whole oat grains on a molecular basis

Background： To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method： The oat grains were kept as raw（control） or heated in an air-draft oven（dry roasting： DO） at 120 °C for 60 min and under microwave irradiation（MIO） for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results： The results showed that rumen degradability of dry matter, protein and starch was significantly lower（P 〈0.05） for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation（-0.99, P 〈 0.01）was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation（0.99, P 〈 0.01） was found between protein β-sheet and crude protein.Conclusion： The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.

Observational Features of Large-Scale Structures as Revealed by the Catastrophe Model of Solar Eruptions

Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceasing motion of the photospheric material through a series of equilibrium configurations. The motion brings energy into the coronal magnetic field until the system ceases to be in equilibrium. The catastrophe theory for solar eruptions indicates that loss of mechanical equilibrium constitutes the main trigger mechanism of major eruptions, usually shown up as solar flares, eruptive prominences, and coronal mass ejections （CMEs）. Magnetic reconnection which takes place at the very beginning of the eruption as a result of plasma instabilities/turbulence inside the current sheet, converts magnetic energy into heating and kinetic energy that are responsible for solar flares, and for accelerating both plasma ejecta （flows and CMEs） and energetic particles. Various manifestations are thus related to one another, and the physics behind these relationships is catastrophe and magnetic reconnection. This work reports on recent progress in both theoretical research and observations on eruptive phenomena showing the above manifestations. We start by displaying the properties of large-scale structures in the corona and the related magnetic fields prior to an eruption, and show various morphological features of the disrupting magnetic fields. Then, in the framework of the catastrophe theory, we look into the physics behind those features investigated in a succession of previous works, and discuss the approaches they used.

The Principle of Square Hole Machining and It＇s Tooling Structure Design

In order to meet the rapid needs of processing square hole in mechanical equipment, the paper expounds the square hole processing method： planetary wheel method, and analyze the principle of tooling structure and process with computer graphics parameters design. The results that, as long as the appropriate parameters, using the above method not only can punch the square hole, can also be processed triangle, the five angle and hexagonal regular polygon holes. The square hole processing method can provide theoretical basis and engineering reliable reference for related engineering and technical personnel.

Investigation of anode shaping process during co-rotating electrochemical machining of convex structure on inner surface

A novel co-rotating electrochemical machining method is proposed for fabricating convex structures on the inner surface of a revolving part.The electrodes motion and material removal method of co-rotating electrochemical machining are different from traditional electrochemical machining.An equivalent kinematic model is established to analyze the novel electrodes motion,since the anode and cathode rotate in the same direction while the cathode simultaneously feeds along the line of centres.According to the kinematic equations of the electrodes and Faraday’s law,a material removal model is established to simulate the evolution of the anode profile in co-rotating electrochemical machining.The simulation results indicate that the machining accuracy of the convex structure is strongly affected by the angular velocity ratio and the radius of the cathode tool.An increase of the angular velocity ratio can improve the machining accuracy of a convex structure.A small difference in the radius of the cathode tool will cause changes in the shape of the sidewalls of the convex structure.The width of the cathode window affects only the width of the convex structure and the inclination a of the sidewall.A relation between the width of the cathode window and the width of the convex structure was obtained.The formation process for a convex structure under electrochemical dissolution was revealed.Based on the simulation results,the optimal angular velocity ratio and cathode radius were selected for an experimental verification,and 12 convex structures were simultaneously fabricated on the inner surface of a thin-walled revolving part.The experimental results are in good agreement with the simulation results,which verifies the correctness of the theoretical analysis.Therefore,inner surface co-rotating electrochemical machining is an effective method for fabricating convex structures on the inner surface of a revolving part.

Applying Petri-Net-Based Reduction Approach for Verifying the Correctness of Workflow Models

The correctness of workflow models is one of the major challenges in context of workflow analysis. The aim of this paper is to provide an improved Petri net-based reduction approach for verifying the correctness of workflow models. To the end, how to represent well-behaved building blocks and control structures of business processes by Petri nets is given at first, and then how to build well-structured process nets is presented. According to the structural characteristics of well-structured process nets, a set of legacy reduction rules are improved and extended, and then a complete Petri-net-based verification approach is proposed. The sound ness and the complexity with polynomial time for the improved re duction method are also proven.

Existence and Uniqueness of Positive Solutions for a System of Multi-order Fractional Differential Equations

In this paper, we study a class of ruin problems, in which premiums and claims are dependent. Under the assumption that premium income is a stochastic process, we raise the model that premiums and claims are dependent, give its numerical characteristics and the ruin probability of the individual risk model in the surplus process. In addition, we promote the number of insurance policies to a Poisson process with parameter λ, using martingale methods to obtain the upper bound of the ultimate ruin probability.

Systematic rationalization approach for multivariate correlated alarms based on interpretive structural modeling and Likert scale

Alarm flood is one of the main problems in the alarm systems of industrial process. Alarm root-cause analysis and alarm prioritization are good for alarm flood reduction. This paper proposes a systematic rationalization method for multivariate correlated alarms to realize the root cause analysis and alarm prioritization. An information fusion based interpretive structural model is constructed according to the data-driven partial correlation coefficient calculation and process knowledge modification. This hierarchical multi-layer model is helpful in abnormality propagation path identification and root-cause analysis. Revised Likert scale method is adopted to determine the alarm priority and reduce the blindness of alarm handling. As a case study, the Tennessee Eastman process is utilized to show the effectiveness and validity of proposed approach. Alarm system performance comparison shows that our rationalization methodology can reduce the alarm flood to some extent and improve the performance.

Collaborative optimization design of process parameter and structural topology for laser additive manufacturing

High-resolution laser additive manufacturing(LAM)significantly releases design free-dom,promoting the development of topology optimization(TO)and advancing structural design methods.In order to fully take advantage of voxelated forming methods and establish the quantitative relationship between the mechanical properties of printing components and multiple process factors(laser-and process-parameters),the concurrent optimization design method based on LAM should cover the process-performance relationship.This study proposes a novel artificial intelligence-facilitated TO method for LAM to concurrently design microscale material property and macroscale structural topology of 3D components by adopting heuristic and gradient-based algorithms.The process–structure–property relationship of selective laser sintering is established by the back propagation neural network,and it is integrated into the TO algorithm for providing a systematic design scheme of structural topology and process parameter.Compared with the classical optimization method,numerical examples show that this method is able to improve the mechanical performance of the macrostructure significantly.In addition,the collaborative design method is able to be widely applied for complex functional part design and optimization,as well as case studies on artificial intelligence-facilitated product evaluation.

Practicing the concept of “structuring” processing in the manufacture of polymer films

Polymer processing is a technology used to transfer raw materials into products with different shapes and functionalities and is a key step for polymer application.After years of development,the polymer processing task has changed from traditional processing,which mainly addresses the specific shapes of articles and focuses on the effect of processing on the structures and properties of polymers,to modern processing,which directly transforms a“designed structure”into commercial products via processing.It is the so-called“structuring”processing.Owing to the unique long-chain nature and slow topological relaxation,polymers are always driven and frozen into different nonequilibrium conformations,providing an effective way to design a given polymer material with desired structure and tunable performances via processing.Among the endless number of processing techniques,film casting is a prototypical pathway involving high supercooling or/and a strong flow field,based on which diverse thin polymer films have been successfully developed.In this review,taking isotactic polypropylene(i PP)film as an example,we highlight the strategy of“structuring”processing,in which we transform various crystalline structures of i PP into diverse commercial film products.

Operational Modal Analysis of a Ship Model in the Presence of Harmonic Excitation

A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm （NExT-ERA） is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies.

AN ESTIMATE OF THE EFFECTS OF LARGE SCALE STRUCTURES ON THE TURBULENT TRANSPORT PROCESSES NEAR WALL

Based on the three-term decomposition model for turbulent flows, the fundamental equations for quasi-periodic motions are obtained, and the approximate analytical solutions of these second-order nonlinear partial differential equations are derived by using the match method. The effects on the mo- mentum, heat and mass transport processes in the wall turbulent flows can be estimated approximately.

THE MICROPHYSICAL STRUCTURE OF SNOW CLOUDS AND THE GROWTH PROCESS OF SNOW PARTICLES IN WINTER IN XINJIANG

The microphysical structure of snow clouds and the growth process of snow crystals were observed by means of instrumented aircraft, weather radar, snow crystal observations etc. in Urumqi region during the winter of 1982. The analysis of three cases show that about 70% of snow mass growth is produced in the lower layer below 2000 m under the cold front, and that the concentration of ice crystals is as high as 60 L^(-1) and the supercooled water is absent in lower clouds. We may infer that the deposition of ice crystals and the aggregation of snow crystals are important processes for the snow development. The microphysical structure of the snow band near the front aloft and its characteristics as a seeder cloud are also described in this paper.

Energy consumption hierarchical analysis based on interpretative structural model for ethylene production

Interpretative structural model(ISM) can transform a multivariate problem into several sub-variable problems to analyze a complex industrial structure in a more efficient way by building a multi-level hierarchical structure model. To build an ISM of a production system, the partial correlation coefficient method is proposed to obtain the adjacency matrix, which can be transformed to ISM. According to estimation of correlation coefficient, the result can give actual variable correlations and eliminate effects of intermediate variables. Furthermore, this paper proposes an effective approach using ISM to analyze the main factors and basic mechanisms that affect the energy consumption in an ethylene production system. The case study shows that the proposed energy consumption analysis method is valid and efficient in improvement of energy efficiency in ethylene production.

Unit Construction in the Formation of Metal Clusters──Investigation on the Metal Cluster CompoundsContaining Fe_2S_2(CO)_6-units

The syntheses and structures of trinuclear Mo (W)-Fe-S cluster[MFe2S2(CO)8 (S,CNSEt2)]- (M=Mo, W), hexanuclear Fe-S cluster [Fe6S6-(CO)12]2- and undecanuclear Cu-Fe-S cluster [Cu5Fe6S6(CO)18(PPh3)2]-, containingFe2S2(CO)6-units bave been summarized and the important vestiges left in their struc-tures reflecting the formation processes of the clusters have been found and discussed.Further inspecting some other typical clusters a regular unit construction in the forma-tion of the metal cluster compounds containing Fe2S2(CO)6-units has been figured outand applied to speculate and predict several new cluster compounds containing Fe2S2(CO)6-units.

Integrating Polymorphic PDMs

Along with the explosive increase of product data management systems (PDMs),integrating polymorphic PDMs is becoming one of the focuses in the field. Aner brief describing several features of PDM, and market requirements and required performance for integrating the polymorphic PDMs, the paper specializes in discussing some key technologies involved in virtual enterprise oriented integrated development. Some implementing strategies and procedures are proposed.