Parameter Optimization Analysis of Viscous Dampers for Dissipation Structure

The design method of parameter optimization of nonlinear viscous dampers for dissipation structure was analyzed based on response surface methods. The method included experimental design, finite element analysis, fitting the response surface function and parameter optimization. Taking a reinforced concrete frame structure for an instance, the mathematical model of parameter optimization of viscous dampers for dissipation structure was established by taking the minimum all damping force as objective function and taking the interlayer maximum displacement less than limits as constraints, and then the damper parameters were optimized using the method of nonlinear programming optimization. The results show that the method of parameter optimization of viscous dampers based on response surface method can ensure the structural displacement is less than limit and the construction cost can be reduced.     

Technique of Surface Reconstruction for Three Dimensional Structure of Chinese Medicihnal Materials

To study the technique of surface reconstruction for Chinese medicinal materials from its cross-sectional images and to display its three dimensional structure.The pattern recognition technique is used to complete the classification and matching of various structures, then the triangle surface approximation is used to produce the 3D surface of the structure.The 3D structure is reconstructed and can be viewed by flexible way based on SGI workstation. The technique and method provided by this paper is contributive to the study and view of various structure of Chinese medicinal materials, and is available to biomedical image processing field.     

Feature-based Surface Model Reconstruction Technique

Surface reconstruction is reproduction process of geometric topology information and feature bases on surface practicality model. The quality of surface reconstruction directly influences performance of production, analysis and manufacture. To improve quality of design and meet requirement of fair, precision, it's researched by the numbers the geometric modeling and constraint of surface reconstruction. Feature-based surface model reconstruction technique is discussed in this article. Combine with 3D model design of motor body covering, an engineering application is given finally.     

Study on Adaptive Sampling and Mesh Generation of Free-form Surfaces Based on Coordinate Measuring Machine

Digitizing of free form surfaces is one of key technologies on the reconstruction of free form surfaces. It is important to know how to sample properly free form surfaces on CMM, which concerns the reconstruction accuracy of free form surfaces and measuring efficiency. The mathematical model of sampling algorithm is proposed based on the concept of the center of gravity. Using the method, the topological information of surfaces can be preserved, and sampling mesh can be self organized. By analyzing and dealing with mesh data received from sampling algorithm, one approach with brevity and higher efficiency is provided on CMM.     

Improved marching cubes by combining case lookup table and adjacency lookup sub-table

The marching cubes (MC) is an effective surface rendering method in three-dimensional visualization for medical image sequence. However, most existing MC algorithms are slow and inefficient because they have to process all the cubes for isosurface extraction. An efficient MC algorithm is proposed by combing the case lookup table and a novel adjacent lookup sub-table to exclude unrelated empty cubes. By explicitly building the fix-length adjacent lookup sub-table that is independent on image sequences, the volumes elements are constrained to those only intersect with the isosurface. Both execution time and temporary storage space are further reduced by incorporating the heap data structure in algorithmic implementation. Experimental results on human head, chest foot CT data sets by using the visualization toolkit package show that the traversal cubes decreases by 95%, and the reconstruction time decreases by 20% without any loss of reconstruction quality. Therefore, the proposed method can remarkably speed up the rendering time and be easily integrated into 3D visualization for clinical application.     

Designing an experiment with quantitative treatment factors to study the effects of climate change

Experiments for studying the effects of climatic change on ecosystems often involve manipulation of one or several quantitative treatment factors of interest. Response surface regression is the method of choice for these types of experiment. Here, we describe the development of a design of a free air CO₂ enrichment experiment with two quantitative treatment factors, that is, elevated temperature and CO₂ enrichment. The design strategy takes account of budget constraints imposing limitations on the number of plots with elevated temperature and CO₂ levels. The approach is based on polynomial regression models and is focussed on an efficient estimation of interaction between the two treatment factors. Extension to more than two factors is straightforward. An analysis of soil moisture data demonstrates the overall suitability of the proposed design to analyse non‐linear interactions of two (or more) global change factors.     

A simplified approach to define the yield surface of concrete-filled square steel tubes subjected to compression-bending

When the plastic hinge method is used to simulate the elasto-plastic properties of concrete-filled steel tubular structures,the plastic interactive yield surfaces of concrete-filled steel tubular column sections need to be defined.Although the fiber model approach can be well applied to the yield surface analysis,the numerical method is still complicated for the real applications.Therefore based on the experimental and theoretical researches on concrete-filled square steel tubular (CFST) members,this paper develops one method to determine the elastic element parameters.Then a simplified approach to quickly define the axial force-moment interactive plastic yield surface of concrete-filled square steel tubular columns is developed through theoretical analysis and a large number of parametric analyses.Finally,the fiber model method is adopted to verify the feasibility and validity of the proposed method.Results of the two methods are in good agreement,which indicates that the proposed method is reliable.     

Profile Characteristics Analysis Using Kauhunen-Loeve Transform

The analysis method for profile characteristics based on Kauhunen Loeve transform is presented. The profile characteristics are represented using eigenvalues and eigenvectors, thus the error surface profile can easily be reconstructed. The main eigenvectors can be used to monitor and predict the surface error. Examples show that this method is feasible and very effective.     

State and Prospects of Physics-Based Free-form Surface Modeling

Physics based modeling is one of the keen free form surface modeling method at present, and it should be a practical surface modeling method in the future. In Physics based modeling, the object is viewed as a physics and not a pure geometry model. According to its physics principle and math representation, the physics based models are mainly classified into two types:energy model and dynamic Lagrangian model. The fundamental theory is introduced, and the principle, development and application state of each model is reviewed. To provide designer more naturally design ability and to introduce more flexible geometric modeling methods are the prospect of future researches on physics based free form surface modeling is outlined at last.     

联合局部和全局稀疏表示的磁共振图像重建方法

针对在压缩传感中独立使用全局或局部稀疏字典所分别导致的图像细节或整体图像结构信息的丢失，提出了一种联合利用局部和全局稀疏约束来捕捉磁共振图像细节和整体结构信息的磁共振图像重建算法。该算法首先从特定的磁共振图像中训练出稀疏字典，然后利用该字典进行局部稀疏编码。其次，利用预定义的全局字典来加强磁共振图像的全局稀疏性。最后，在局部和全局稀疏的共同约束下，利用非线性共轭梯度算法来对重建模型进行求解。整个重建过程可以重复迭代以逐步改善重建质量。实验结果表明：当下采样因子达到10时，相比于字典学习算法（dictionary learning MRI，DLMRI），提出的算法在重建质量上可以提高1-6 dB。     

Dropwise Condensation Heat Transfer Coefficient on the Horizontal Circular Surface with Radial Gradient Surface Energy

A theoretical model is developed for the dropwise condensation heat transfer on the horizontal circular surface with radial gradient surface energy based on the heat transfer model of individual condensate drop and the size distribution model of condensate drop on homogeneous condensation surface.The effect of variation of contact angle on the gradient surface on condensation heat transfer and condensate drop size distribution is taken account of in this model.The theoretical calculation method was obtained to predict the dropwise condensation heat transfer coefficient on the horizontal circular surface with radial gradient surface energy under various wall subcooled temperature,contact angle profile on wall surface,and working fluid.The effects of surface energy gradient,wall subcooled temperature,and thermophysical properties of condensate on the condensation heat transfer are discussed respectively.The calculation results show that the condensation heat transfer coefficient increases slightly with the increase of wall subcooled temperature.As latent heat and surface tension increasing,the condensation heat transfer coefficient increases.A larger surface energy gradient induces a larger condensation heat transfer coefficient.     

Analysis of Low frequency Noise of Bridge Considering the Vibration of Bridge Deck

Under the dynamic load of vehicle, the bridge will vibrate and radiate low frequency noise which is harmful to human health. A method for predicting the low frequency noise is proposed based on the analysis of vibration of bridge deck. The prediction includes the analysis of vehicle bridge coupling vibration considering the bridge deck and the analysis of sound radiation and propagation in the air. By taking a bridge with low frequency noise as example, the vibration and sound radiation of the bridge are analyzed respectively by the current method and the previous method based on the grillage model. The results show that the prediction based on the vibration of bridge deck is more accurate. Furthermore, the measures to reduce the noise of bridge are explored, and the results indicate that a smoother road surface leads to lower noise. But when the condition of road surface is up to the extremely good standard defined by ISO, the effect of reducing the roughness of surface is not significant. Also, strengthening the crossbeam in the bridgehead is a simple and effective way to reduce the low frequency noise of bridge.     

Calculating the Hollowing-center Grounding Device Resistance Based on the Surface Charge Simulation Method

An equivalent model for hollowing-center grounding device is proposed, the hollowing-center grounding device resistance is calculated with the surface charge simulation method and the computer programme is programmed based on this model. The accuracy of the model and method is validated by experimentation.     

响应面法不确定性参数对行星架静强度的影响

不确定性参数对行星架静强度的影响,取行星架强度最薄弱的部位-前轴承支座挖根(清根处)为研究对象,采用参数方差分析法从不确定性参数中挑选显著参数,并利用D最优抽样法选取样本点组合,计算精细有限元模型清根处应力响应值,继而基于最小二乘估计建立多项式回归响应面模型。基于快速响应面模型,利用蒙特卡洛模拟法和统计分析法研究显著性参数过盈量、铸造圆角和腹板公差对清根处第一主应力的影响,并从可靠度角度对清根处静强度进行评估。研究发现过盈量和前后腹板偏差的离散性对清根处静强度影响明显,同时行星架可靠度达到99.3%,表明在考虑了GL和IEC安全系数后,行星架可靠度仍然非常高。     

Prediction of Ground Surface Movements Due to Shield Tunneling with Tail Grouting Heave

Compared with conventional tunneling methods, ground movements behave some different patterns, such as surface heave induced by tail grouting. Through the analysis of ground surface heave due to tail grouting in three cases, the applicability of Gaussian equation and six analytic methods (including Mindlin's problem, Sagaseta method, Verruijt-Booker method, Loganathan-Poulos method, Chi method and Park method) to predict ground surface heave induced by tail grouting were verified. Based on case studies, one modified Peck equation was proposed to calculate ground surface movements, including grouting heave due to shield tunneling. The results show that the Gaussian equation and Chi method are applicable to calculate surface heave due to shield tail grouting, and the Modified Peck Equation can predict the total transversal ground surface movements rationally.     

Experimental Study for the Movement of Liquid Droplets on the Surface with Gradient Surface Energy

By using the chemical vapor deposition (CVD), a surface with gradient surface energy is fabricated based on the treated silicon chip. The dodecyltrichlorosilane (C_(12)H_(25)Cl_3Si) and Octrytrichlorosilane (C_(8)H_(17)Cl_3Si) are used as the source of silanization. By using the measurement of sessile drop method, the surface with gradient surface energy was characterized by measuring the contact angle of small water which lied on the surface of the treated silicon chip. The experiment shows the liquid droplets are driven to move from hydrophobic to hydrophilic zone on the gradient surface which is placed horizontally, the diameter of the droplets are 1~3 mm, and the single droplet reached the maximum velocity of up to 0.9 m/s. Based on the experimental results, the mechanical of the movement of the liquid droplet on the gradient surface is researched.     

Research & Operation on Mathematical Methods used in NC System of Profile followed Grinding Robot

Several mathematic methods used in the numerical control system of profile followed grinding robot are described. Cubic parametric Spline surface function is employed to fit the geometric model of the surface grinded with high precision. Improvement of the physics performance of blade is obtained by reconstructing the large size surface of turbine blade based on calculation geometry. Graphic linear transfer technique is provided to users with unique format of programming. Graphic non linear transfer technique is used to solve some more difficult problems successfully including transformation of the coordinates of comtrolled points in multicoordinates system, adjustment of the attitude of grinding head as well as realization of constant pressure grinding. All these mathematics methods are demonstrated feasible and efficient in actual practice and are valuable in developing large size surface grinding robots.     

An Image Reconstruction Fast Algorithm Based on Orthogonal Wavelets Derived from Symmetric Scale Functions

A new image reconstruction algorithm is presented, based on orthogonal wavelets derived from symmetric scale functions. The analysis and practice show that the method lessens greatly the computational time,and improves the reconstruction quality.     

兰科植物种子表面消毒方法及其对种子萌发率的影响

兰花的种子夹在贮藏时期易于开裂而使种子污染,因而不适用于无菌的组培作业。为探究合适兰科植物种子的表面消毒方法,并将其应用到无菌萌发研究及生产之中,以兰科植物贵州地宝兰(Geodorum eulophioides)的种子为研究对象,利用一种尼龙网种子袋对兰科植物微小种子进行了表面消毒方法比较的研究。在试验中比较了不同消毒剂及不同消毒时间对种子萌发率的影响。结果表明,75%酒精消毒30 s会使贵州地宝兰种子失去活性,不适用于其表面消毒;2% NaClO溶液的消毒效果与消毒时间成正比,当消毒时间增加为6 min时没有污染,消毒效果较好,种子萌发率达到33.88%,且其对贵州地宝兰种子萌发率后续生长无影响,因此是一种有效的表面消毒方法,可适用于兰科植物种子无菌萌发的研究及生产实践。     

Average surface roller pressure calculation method of roller mill

Hydraulic system pressure, contact surface between grinding roller and materials and grinding roller force of roller mill are analyzed. A new roller pressure calculation method named average surface roller pressure calculation method is proposed,and the corresponding theoretical formula is derived from three different perspectives, including roller pressure numerical calculation, stress and strain of main components and mill power through the calculation of real samples. The average surface roller and traditional average material roller pressure are compared to verify the correctness and accuracy of the proposed method. Design parameters such as the grinding roller structure, material maximum size, layer height and working pressure of the hydraulic system on the influence of roller are analyzed according to the formula of roller pressure. The research results provide theoretical basis for the selection of design parameters and the design calculation of structural strength for roller mill.