职业学校信息化建设的风险与对策研究

总结了职业学校信息化建设的现实困境,分析了职业学校信息化建设五个方面的风险,基于职业学校信息化建设规模大、复杂性高的特点,提出将软件工程中的“螺旋模型”应用于职业学校信息化建设、建立“建管用评”职业学校信息化建设的长效工作机制等对策,为做好、做实、做强职业学校信息化建设工作提供了有效指导。

MATLAB-Based Simulation of Buoyancy-Driven Underwater Glider Motion

The mass configuration of the buoyancy-driven underwater glider is decomposed and defined. The coupling between the glider body and its internal masses is addressed using the energy law. A glider motion model is established, and the corresponding simulation program is derived using MATLAB. The characteristics of the glider motion are explored using this program. The simula- tion results show that the basic characteristic of a buoyancy-driven underwater glider is the periodic alternation of downward and upward motions. The glider's spiral motion can be applied to missions in restricted regions. The glider's horizontal velocity, gliding depth and its motion radius in spiral motion can be changed to meet different application purposes by using different glider parameter designs. The simulation also shows that the model is appropriate and the program has strong simulation functions.

Numerical Simulation of the Flow around Marine Propeller Series

The objective of marine propeller design optimization study is to obtain a propeller with minimum power absorption, maximum efficiency and good materials resistance. In this study, results of numerical simulation carried out on the flow around a conventional marine propeller are presented. The investigation focused on the aspects related to the influence of skew magnitude, thickness and blade number on the propeller performances. First, open water performances of a conventional propeller model DTMB 4148 was estimated using RANS （Reynolds Averaged Navier-Stokes） method. The flow around rotating propeller model was analyzed in the steady state using RANS approach of the commercial CFD （computational fluid dynamics） code fluent. The results provide good agreement with literature data. Numerical results show that the number of blades has an influence on the open water performances of marine propellers. It＇s noticed that the best propeller has four or five blades from only the hydrodynamic aspect. The thickness blade effect has been studied for the same propeller model and compared to the blade with three different thickness values. Results of the calculation show that the blade thickness increases moderately the propeller efficiency. Finally, numerical simulation is performed to study the magnitude skew effect on the propeller blade performance, so three different models were generated. The results of the simulation show that the skew distribution has a positive effect on the open water performances of the marine propellers.

Suppression of Spiral Wave in Modified Orengonator Model

In this paper, a spatial perturbation scheme is proposed to suppress the spiral wave in the modified Orengonator model, which is used to describe the chemical reaction in the light-sensitive media. The controllable external illumination Ф is perturbed with a spatial linear function. In our numerical simulation, the scheme is investigated by imposing the external controllable illumination on the space continuously and/or intermittently. The numerical simulation results confirm that the stable rotating spiral wave still can be removed with the scheme proposed in this paper even if the controllable Ф changed vs. time and space synchronously. Then the scheme is also used to control the spiral wave and turbulence in the modified Fitzhugh-Nagumo model. It is found that the scheme is effective to remove the sable rotating and meandering spiral wave but it costs long transient period and intensity of the gradient parameter to eliminate the soiral turbulence.

Mathematic model and tooth contact analysis of a new spiral non-circular bevel gear

A novel spiral non-circular bevel gear that could be applied to variable-speed driving in intersecting axes was proposed by combining the design principles of non-circular bevel gears and the manufacturing principles of face-milling spiral bevel gears.Unlike straight non-circular bevel gears,spiral non-circular bevel gears have numerous advantages,such as a high contact ratio,high intensity,good dynamic performance,and an adjustable contact region.In addition,while manufacturing straight non-circular bevel gears is difficult,spiral non-circular bevel gears can be efficiently and precisely fabricated with a 6-axis bevel gear cutting machine.First,the generating principles of spiral non-circular bevel gears were introduced.Next,a mathematical model,including a generating tooth profile,tooth spiral,pressure angle,and generated tooth profile for this gear type was established.Then the precision of the model was verified by a tooth contact analysis using FEA,and the contact patterns and stress distributions of the spiral non-circular bevel gears were investigated.

HELICITY ANALYSIS FOR HIGH-WIND AND UNCOMMON RAINSTORM PROCESSES OVER YUNNAN IN EARLY SUMMER

Helicity was applied to analyze several high-wind and rainstorm processes, which occurred from May to June, 2001 over Yunnan in early summer. The results of diagnostic analyses show that the rainstorm occurs in the area in which hp is positive at 700 hPa and energy is unstable. The change of helicity can reflect the movement and development of synoptic system and the position and intensity of the rainstorm. The value of hp is a negative center at the upper level and a positive at the lower level over the rainstorm position; moreover it can reflect the characteristics of vertical distribution and rotational motion.

Computational Simulation of Complex Structure Fancy Yarns

A study is reported for mathematical model and simulative of complex structure fancy yams. The investigated complex structure fancy yams have a multithread structure composed of three components core, effect, and binder yams. In current research the precondition was accepted that the cross-sections of the both two yams of the effect intermediate product in the complex structure fancy yam remain the circles shaped, and this shape does not change during manufacturing of the fancy yam. Mathematical model of complex structure fancy yarn is established based on parameter equation of space helix line and computer simulative is further carried out using the computational mathematical tool Matlab 6.5. Theoretical structure of fancy yam is compared with an experimental sample. The simulative system would help for further the set of informative in designing of new assortment of the complex structure fancy yarns and prediction of visual effects of fancy yams in end-use fabrics.

Model test of helical angle effect on coal loading performance of shear drum

The work presented in this paper focuses on improving coal loading performance of shear drum.Employing the similarity theory,we carried out a dimensional analysis of the correlation parameters which influence coal loading performance of shear drum.On the basis of similarity criterion,proportional relationship between the model and the prototype was taken on the condition of taking 1/3 as the similarity coefficient.Besides taking 1600 mm drum as the prototype,four helical angle models of shearer drums(15°,18°,21°,24°) were developed.Simultaneously,based on an established cutting test-bed,coal loading performance tests for the four drums were carried out at the same drum rotational and haulage speeds.After analyzing the data of coal-loading performance and torque,we concluded that:both the coal loading performance and torque vary along the track of the parabola with the opening side facing downwards;the best coal loading performance arises when the helical angle is at 19.3°,while the biggest torque arises at 22.1°;and the coal loading performance had nonlinear relationship with the torque.

Kinematic Analysis and Trajectory Planning of J-Groove Welding Robot

This paper introduces the complexity and particularity of tube-sphere intersection weld(J-groove weld) and establishes the mathematical model of tube-sphere intersection trajectory.Based on the characteristics of J-groove welds,the computational process of welding gun orientation is first simplified.Then the kinematic algorithm of a welding robot is obtained according to screw theory and exponential product formula.Finally,Solidworks and SimMechanics are employed to simulate the kinematics of the welding robot,which proves the feasibility of the kinematic algorithm.

RESEARCH AND IMPROVEMENT OF SPIRAL BUNKER

A great attention has been paid to slowing the degradation of coal nowadays. The spiral bunker is the main measure to lower the degradation. In this paper the application and research of spiral bunker are introduced. And two non-normal spiral chutes are discussed. One is in the tangential direction of the inner wall of the bunker, another is in the direction of the diameter of the bunker. Mathematical models of the non-normal spiral chutes are set up to optimize the geometrical parameters of the spiral curved surface, which would ensure that coal travels smoothly to the bottom of the bunker. The results would be useful for designing and retrofitting the spiral bunker.

Contributions of qqqq Components to Axial Charges of Proton and N(1440)

The axial charges of the proton and N（1440） are studied in the framework of an extended constituent quark model （CQM） including qqqqq components. The cancellation between the contributions of qqq components and qqqqq components gives a natural explanation to the experimental value of the proton axial charge, which can not be well reproduced in the traditional CQM even after the SU（6） × O（3） symmetry breaking is taken into account. The experimental value of axial charge pins down the proportion of the qqqqq component in the proton to about 20%, which is consistent with the ones given by the strong decay widths and helicity amplitudes. Besides, an axial charge for N（1440） about 1 is predicted with 30% qqqqq component, which is obtained by the strong and electromagnetic decays.

Effects of parameters on rotational fine blanking of helical gears

The application of fine blanking to the manufacturing of helical gears directly from a strip has been restricted due to the traditional linear cutting stroke of the punch and die.In this work,rotational fine blanking which combined the linear and rotational motion of punch and counterpunch was applied for the forming of helical gears.A three-dimensional(3D) rigid-plastic finite element model was developed on the DEFORM-3D platform.By finite element simulation and analysis,the influences of key parameters on the punch load and cut surface were investigated.It is shown that: 1) with increasing the counterforce or helical angle,the punch load and the depth of die roll increase; 2) with increasing blank holder force,the punch load increases while the depth of die roll decreases; 3) V-ring indenter facilitates an improvement in the quality.The results of this research reveal the deformation mechanism of rotational fine blanking of helical gears,and provide valuable guidelines for further experimental studies.

Destruction of Spiral Wave Using External Electric Field Modulated by Logistic Map

Evolution of spiral wave generated from the excitable media within the Barkley model is investigated. The external gradient electric field modulated by the logistic map is imposed on the media （along x- and y-axis）. Drift and break up of spiral wave are observed when the amplitude of the electric field is modulated by the chaotic signal from the logistic map, and the whole system could become homogeneous finally and the relevant results are compared when the gradient electric field is modulated by the Lorenz or Rossler chaotic signal.

ANALYTIC STUDY ON POTENTIAL INSTABILITY AND SPIRAL STRUCTURE OF RAIN CLUSTERS

This paper presents a study on potential instability and spiral structure of unstable rain clusters.First,we develop a linearized non-axisymmetrical mathematic model for rain clusters in circular cylindrical coordinates and acquire its analytic solution.Second,we discuss the potential instability of non-axisymmetrical rain clusters.Finally,we conclude that spiral structures can exist in rain clusters.Our analysis indicates that potential instability occurs when humid stratification coefficient is less than zero.Unstable growth rate increases with the increase of the absolute value for humid stratification coefficient.The simpler the vertical structure of perturbation,the thicker the inversion layer;additionally,the smaller the radius of the rain clusters,the larger the unstable growth rate.Simulation results agree well with those from observation and forecast.The spiral structure simulated by our model is similar to a radar echo,suggesting that rain clusters with spiral structures can occur in the atmosphere.In addition,they are generally close to the model solution in this work.

Features of Motion of Soliton Transported Bio-energy in Aperiodic α-Helix ProteinMolecules with Three Channels

The structure aperiodicities can influence seriously the features of motion of soliton excited in the α-helix protein molecules with three channels. We study the influence of structure aperiodicities on the features of the soliton in the improved model by numerical simulation and Runge-Kulta method. The results obtained show that the new soliton is very robust against the structure aperiodieities including large disorder in the sequence of mass of the amino acids and fluctuations of spring constant, coupling constant, dipole-dipole interactional constant, ground state energy and chain-chain interaction. However, very strong structure aperiodieities can also destroy the stability of the soliton in the α-helix protein molecules.

Prediction method for surface finishing of spiral bevel gear tooth based on least square support vector machine

The predictive model of surface roughness of the spiral bevel gear (SBG) tooth based on the least square support vector machine (LSSVM) was proposed.A nonlinear LSSVM model with radial basis function (RBF) kernel was presented and then the experimental setup of PECF system was established.The Taguchi method was introduced to assess the effect of finishing parameters on the gear tooth surface roughness,and the training data was also obtained through experiments.The comparison between the predicted values and the experimental values under the same conditions was carried out.The results show that the predicted values are found to be approximately consistent with the experimental values.The mean absolute percent error (MAPE) is 2.43% for the surface roughness and 2.61% for the applied voltage.

NC Machining of Spiral Bevel Gear and Hypoid Gear Based on Unity Transformation Model

A unity transformation model (UTM) was presented for flexible NC machining of spiral bevel gears and hypoid gears. The model can support various machining methods for Gleason spiral bevel gears and hypoid gears, including generation machining and formation machining for wheel or pinion on a universal five-axis machining center, and then directly produce NC codes for the selected machining method. Wheel machining and pinion machining under UTM were simulated in Vericut 6.0 and tested on a five-axis machining center TDNC-W2000 with NC unit TDNC-H8. The results from simulation and real-cut verify the feasibility of gear machining under UTM as well as the correctness of NC codes.

Growth Kinetics and Chitosan Flocculation of Spirufina platensis Algae

S. platensis （Spirulinaplatensis） algae were grown in batch reactors at 30 ± 1℃ with a continuous illumination of 50 ±2 μmol·m^-2·s^-1 using different growth media and air flow rates. A modified Gompertz kinetic model was applied to estimate the maximum concentration of algae and the growth rate at different conditions. A peak cell productivity of 21.91 mg·L^-1·day^-1 （dry biomass） was determined using commercial nutrient media （F/2, part A and part B） and modified Zarrouk medium at an air flow rate of 3 L·L^-1·min^-1. Using the commercial media at high concentrations yielded high biomass concentrations. The results of the modified Gompertz kinetic model indicated that the highest growth rate was 0.118 g·L^-1·day^-1. This growth rate was determined for S. platensis cultivated using 0.399 mL·L^-1 of the commercial media. Response surface methodology was applied to optimize the parameters （temperature, pH, and chitosan dose） that affect the efficiency of the flocculation of S. platensis. An optimum flocculation of 98.7% was determined at a pH, temperature, and chitosan dose of 5.5, 30℃, and 75 mL·L^-1, respectively.

Hemodynamic performance of coil embolization and stentassisted coil embolization treatments:a numerical comparative study based on subject-specific models of cerebral aneurysms

Hemodynamic characteristics such as blood velocity,blood pressure,flow impingement,wall shear stress and oscillatory shear index are considered to play important roles in the initiation,growth,rupture and recurrence of the cerebral aneurysms.Endovascular therapy is widely implemented to treat the cerebral aneurysms by releasing coils into the aneurysm sac for limiting the blood flow to the sac and stent-assisted coil embolization is adopted to occlude the wide-necked or complex aneurysms.Some researchers believe that stents are not only a mechanical device but may act as a biological system and contribute to vessel wall healing.Hemodynamics simulation helps people understand the effect of hemodynamic characteristics on the recurrence of the coiled aneurysm and it also benefits the interventional planning of neurosurgeons.This study constructed the numerical model for a subject-specific ICA aneurysm treated with stent-assisted coil embolization,which combined the coiled model of the aneurysm with a porous stent placement,and simulated the pulsatile blood flow in these aneurysm models.When a stent was placed across the aneurysm orifice in the coiled aneurysm,the high wall shear stress around the distal aneurysm root was reduced more than that of the coiled aneurysm without a stent.The simulated results point to the conclusion that the stent not only protects the parent artery from occlusion due to extension of coils or thrombosis,but may also reduce the recurrence risk of the stent-assisted coiled aneurysm.

New actuator disk model for propeller-aircraft computation

There is a growing interest in propellers for transport aircraft as well as regional airliners from the viewpoint of energy saving. An important consideration for utilizing a propeller propulsion system on aircraft is the aerodynamic interaction between the propeller slipstream and other aerodynamic surfaces. It is therefore necessary to use a simplified but relatively accurate tool for propeller modeling, with the widely used actuator disk model. The advantage of this model is that it is easy to use and inex- pensive in terms of computation time required. In addition, it also produces acceptable results. In this study, a new regionalized actuator disk model was utilized in the analysis of propeller slipstream interference effects on a real four-propeller aircraft. The results are compared with the cases of inactive actuator disks, which shows that the propeller slipstream causes an increase in the lift and drag coefficients. An evident yawing effect caused by the rotating slipstream was noticed, which should be taken into account in the design phase. The regionalized actuator disk model is evaluated as a fast and relatively accurate model for propeller preliminary design.