兼顾经济性和可靠性的配电网待修线改造方法研究

为兼顾配电网待修线改造方案的经济性和可靠性,促进配电网精准化投资,文章提出一种考虑经济性和可靠性的配电网待修线改造方法。首先,引入一种故障率指标模型,可直接由线路状态评估量得到线路故障率;然后使用检修总费用和可靠性指标边际提升2个目标函数,建立了离散非线性多目标优化模型;同时对非支配排序遗传算法NSGA-Ⅱ(non-dominated sorting genetic algorithm)进行了适当改进;最后通过实例分析验证了所提模型和算法的有效性与可行性。

浅析高职二维动画上色课程中像素画教学的应用与改革

文章针对高职二维动画上色课程的教学特点、结合自身在教育教学过程中心得体会、教学中出现的诸多问题进行思考、探索及研究。文章积极提出可以在高职基础课程中增加像素画教学内容,将像素画教学和二维动画上色课程按类似点有机结合,使二者相辅相成,有效提高二维动画上色课程的学习效率、教学质量和教学水平。

3D打印技术在航空航天电缆产品装配工装的应用研究

本文主要介绍了3D打印技术在航空航天电缆产品装配过程中的应用,通过对电缆产品装配过程分析,将3D打印技术进行植入性研究,详细介绍了电缆装配布线工装、修线工装在3D打印技术下的设计方法及根据设计方法下的工装研究状况,并展望3D打印技术在电缆产品生产中的发展趋势。

改革现有车辆检修分工,缩短列车停留时间

目前我国机辆检修工作的分工，不利于加速车辆周转和高效率的运输。列检所的密布和列车停点多，停留时间长，主观上想用现有这样的管理办法来提高列车质量作到万无一失，确保行车安全。

Upper bound solution for supporting pressure acting on shallow tunnel based on modified tangential technique

Based on the nonlinear failure criterion and the upper bound theorem, the modified tangential technique method was proposed to derive the expression of supporting pressure acting on shallow tunnel. Instead of the same stress state, different normal stresses on element boundaries were used. In order to investigate the influence of different factors on supporting pressures, the failure mechanism was established. The solution of supporting pressure, with different parameters, was obtained by optimization theory. The corresponding failure mechanism and numerical results were presented. In comparison with the results using the single tangential technique method, it is found that the proposed method is effective, and the good agreement shows that the present solution of supporting pressure is reliable.

Dual optimization image repair algorithm based on linear structure and optimal texture

The performances of repaired image depend on the local information in the repaired area and the consistency between the repair directions with structural content.Image repair algorithm with texture information performs well in repairing seriously damaged images,but it has bad performances when the images have the abundant structure information.The dual optimization image repair algorithm based on the linear structure and the optimal texture is proposed.The algorithm uses the double-constraint sparse model to reconstruct the missed information in large area in order to improve the clarity of repaired images.After adopting the preference of Criminisi priority,the image repair algorithm of self-similarity characteristics is proposed to improve the fault and fuzzy distortion phenomena in the repaired image.The results show that the proposed algorithm has more clarity in the image texture and structure and better effectiveness,and the peak signal-to-noise ratio of the repaired images by proposed algorithm is superior to that by other algorithms.

Novel Solutions of KdV Equation

Some novel solutions of the KdV equation are obtained through the modified bilinear B?cklund transformation.

A Modified Logvinovich Model For Hydrodynamic Loads on an Asymmetric Wedge Entering Water with a Roll Motion

The water entry problem of an asymmetric wedge with roll motion was analyzed by the method of a modified Logvinovich model (MLM). The MLM is a kind of analytical model based on the Wagner method, which linearizes the free surface condition and body boundary condition. The difference is that the MLM applies a nonlinear Bernoulli equation to obtain pressure distribution, which has been proven to be helpful to enhance the accuracy of hydrodynamic loads. The Wagner condition in this paper was generalized to solve the problem of the water entry of a wedge body with rotational velocity. The comparison of wet width between the MLM and a fully nonlinear numerical approach was given, and they agree well with each other. The effect of angular velocity on the hydrodynamic loads of a wedge body was investigated.

Modified nonlinear chirp scaling algorithm for curvilinear trajectory synthetic aperture radar

The original nonlinear chirp scaling(NCS) algorithm was extended for high precision processing of the highly squinted curvilinear trajectory synthetic aperture radar(CTSAR).Based on the analysis of slant range model and the frequency spectrum characteristics of the echo signal,a novel nonlinear chirp scaling function and more complex phase compensation factors with both velocity and acceleration parameters were proposed in the new algorithm for accommodation to curvilinear trajectory.The processing flow and computational complexity of modified NCS algorithm were fundamentally the same as the original NCS algorithm.However,the higher order phase compensation,range cell migration correction(RCMC) and range-variant secondary range compression(SRC) caused by the non-linear aperture and the severe range-azimuth coupling were accomplished accurately and efficiently without interpolation.Simulation results show that data acquired with a curvilinear aperture and a squint angle up to about 50° for X-band can be processed with no evident degradation of impulse response function.

New Predictor-Corrector Methods Based on Exponential Time Differencing forSystems of Nonlinear Differential Equations

We present the new predictor-corrector methods for systems of nonlinear differential equations, based on the method of exponential time differencing. We compare the present schemes with the explicit multistep exponential time differencing and Adams–Bashforth–Moulton method. The numerical results show that the schemes are more accurate and more efficient than Adams predictor-corrector method. The exponential time differencing method has been developed and perfected by the present studies.

Revision of P-wave Velocity and Thickness of Hydrate Layer in Shenhu Area, South China Sea

To revise P-wave velocity and thickness of the hydrate layer in the Shenhu area of the South China Sea, acoustic and resistivity logging curves are reanalyzed. The waterlogging phenomenon is found in the shallow sediments of five drilling wells, which causes P-wave velocity to approximate the propagation velocity of sea water(about 1500 m s-1). This also affects the identification of the hydrate layer and results in the underestimate of its thickness. In addition, because there could be about a 5 m thick velocity ramp above or below the hydrate layer as interpreted by acoustic and resistivity logging curves, the recalibrated thickness of this layer is less than the original estimated thickness. The recalibrated P-wave velocity of the hydrate layer is also higher than the original estimated velocity. For the drilling well with a relatively thin hydrate layer, the velocity ramp plays a more important role in identifying and determining the thickness of the layer.

A Systematic Study of the Forbidden Pitch in the CD Through-Pitch Curve for Beyond 130nm

The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1.4 wavelength/ NA （numerical aperture）,is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value （the depth of the ＂dip＂） and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD ＂dip＂. We conclude that the dip depth is very sensitive to the change in image contrast.

Comparison of a modified anoscope and the purse-string anoscope in stapled haemorrhoidopexy

AIM： To compare the results of the anoscope of the PPH kit and a modified anoscope during stapled haemorrhoidopexy. METHODS： The hospital records of 37 patients who underwent stapled haemorrhoidopexy between 2001 and 2006 were reviewed. The purse-string suture anoscope in the PPH kit was used on 15 patients （Group 1）, and the modified anoscope was used on 22 patients （Group 2）. Demographic characteristics of the patients, operation time, surgeon＇s performance, analgesic requirement, and complications were compared. RESULTS： Operation time was significantly longer in Group 1 （42.0 4- 8.4 min vs 27.7 4- 8.0 min, P = 0.039）. The surgeons reported their operative performance as significantly better in Group 2 （the results of the assessments were poor in ten, medium in four and good in one in Group 1, while good in all patients in Group 2, P 〈 0.001）. The need for haemostatic sutures was significantly higher in Group 1 （six cases） and was needed in two cases in Group 2 （P = 0.034）. CONCLUSION： Operation time decreased and the surgeon＇s satisfaction increased with use of the modified anoscope, and fewer haemostatic sutures were required if the surgeon waited longer before and after firing the stapler.

Modified Lindstedt-Poincaré Method for Obtaining Resonance Periodic Solutions of Nonlinear Non-autonomous Oscillators

A modified Lindstedt-Poincar＆#233; （LP） method for obtaining the resonance periodic solutions of nonlinear non-autonomous vibration systems is proposed in this paper. In the modified method, nonlinear non-autonomous equa-tions are converted into a group of linear ordinary differential equations by introducing a set of simple transformations. An approximate resonance solution for the original equation can then be obtained. The periodic solutions of primary, super-harmonic, sub-harmonic, zero-frequency and combination resonances can be solved effectively using the modi-fied method. Some examples, such as damped cubic nonlinear systems under single and double frequency excitation, and damped quadratic nonlinear systems under double frequency excitation, are given to illustrate its convenience and effectiveness. Using the modified LP method, the first-order approximate solutions for each equation are obtained. By comparison, the modified method proposed in this paper produces the same results as the method of multiple scales.

Shape modification of Bézier curves by constrained optimization

The Bézier curve is one of the most commonly used parametric curves in CAGD and Computer Graphics and has many good properties for shape design. Developing more convenient techniques for designing and modifying Bézier curve is an im- portant problem, and is also an important research issue in CAD/CAM and NC technology fields. This work investigates the optimal shape modification of Bézier curves by geometric constraints. This paper presents a new method by constrained optimi- zation based on changing the control points of the curves. By this method, the authors modify control points of the original Bézier curves to satisfy the given constraints and modify the shape of the curves optimally. Practical examples are also given.

Lubrication characteristics of cycloid pin wheel transmission of RV reducer

In order to analyze the lubricating characteristics at different meshing points in the cycloid pin wheel transmission process,the cycloid gear teeth were discretized,combined with the kinematic analysis of the cycloid pin gear transmission and the contact analysis of the gear teeth.The progressive mesh densification method(PMD)was used to numerically solve the film thickness.The influence of the design parameters and process parameters on the lubrication characteristics was analyzed.The elastohydrodynamic lubrication and mixed lubrication characteristics at different contact points were obtained.The optimal meshing area of the cycloid gear tooth was determined,and the film thickness ratio,contact load ratio,maximum contact pressure at different points,average film thickness and roughness after contact deformation were analyzed.The conclusion of this study provides effective guidance for the research on the modification of cycloid gear teeth.

Constitutive equations of 1060 pure aluminum based on modified double multiple nonlinear regression model

In order to study the work-ability and establish the optimum hot formation processing parameters for industrial 1060 pure aluminum, the compressive deformation behavior of pure aluminum was investigated at temperatures of 523?823 K and strain rates of 0.005?10 s?1 on a Gleeble?1500 thermo-simulation machine. The influence rule of processing parameters (strain, strain rate and temperature) on flow stress of pure aluminum was investigated. Nine analysis factors consisting of material parameters and according weights were optimized. Then, the constitutive equations of multilevel series rules, multilevel parallel rules and multilevel series &parallel rules were established. The correlation coefficients (R) are 0.992, 0.988 and 0.990, respectively, and the average absolute relative errors (AAREs) are 6.77%, 8.70% and 7.63%, respectively, which proves that the constitutive equations of multilevel series rules can predict the flow stress of pure aluminum with good correlation and precision.

Dynamic inverse control of feedback linearization in ballistic correction based on nose cone swinging

It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.

Ranging Error Correction Based on a Prior Error Model

Wireless technology provides accurate positioning in indoor environments using time of arrival(TOA) based ranging techniques. However, the positioning accuracy is degraded due to the ranging errors caused by multipath and non-line-of-sight(NLOS) propagation. In this paper, a ranging error correction method is proposed to improve positioning performance. A TOA ranging error model(TREM) is built to provide the prior information for ranging error correction first. The mean value of TREM within a certain interval is used as the ranging error correction value(RECV). As the RECV may be unreasonable sometimes, we adjust it according to the actual positioning situation and then exploit the final RECV to correct ranging data. The experimental results show that the proposed method could well reduce ranging errors and the positioning performance is obviously improved when using corrected ranging data.

The DNA injury-repair of esophageal cancer EC109 cells to diallyl trisulfide (DATS) combining radiation

Objective: The aim of our study was to investigate the effect of diallyl trisulfide (DATS) combining radiation on DNA injury-repair of Esophageal cancer EC109 cells. Methods: Using 10 and 20 μg/mL DATS on EC109 cells, and taking X-ray radiation 24 h later. Investigate the radiosensitization effect of DATS on EC109 cells by clone formation, and the mechanism of DNA injury-repair by Comet Assay. Results: The clone formation resulted that DATS had radiosensitization effect on EC109 cells. Radiosensitization enhancement ratios of 10 and 20 μg/mL DATS in combination with radiation were 1.55, 1.64 (Do) and 1.43, 1.75 (Dq) respectively. In the comet assay, the TM (tail moments) of 20 μg/mL DATS combining radiation group lines at 0 h, 2 h, 6 h and 24 h were 7.16 ± 2.61, 3.65 ± 2.06, 2.09 ± 0.83, 1.45 ± 1.37 respectively. They were slightly increased than radiation group (0.95 ± 0.65, 0.11 ± 0.07, 0.1 ± 0.05, 0.11 ± 0.08) and DATS group (1.81 ± 1.23, 1.58 ± 1.40, 0.45 ± 0.25, 0.60 ± 0.40) (P < 0.01). The result showed that DATS combining radiation had the effect of increasing DNA damage and inhibiting DNA repair on EC109 cells. Conclusion: DATS has radiosensitization effect on Esophageal cancer EC109 cells. And the effect is probably related with DNA injury-repair.