复合土钉支护转角有利影响范围

基坑复合土钉墙转角处有明显的空间效应,受力变形较小,对支护结构有利,但不清楚转角定量的有利影响范围,目前设计中仍按照与基坑中部一样保守设计,为在此范围内降低土钉用量,避免保守设计,对水泥土搅拌桩复合土钉支护结构建立了全尺寸整体三维有限元模型,这种模型包含基坑的转角,能考虑基坑的空间效应,通过建立接触面单元,能考虑土体和搅拌桩、土体和土钉的相互作用,量化分析了基坑转角对支护结构受力和变形的有利影响范围,计算结果表明,基坑转角对开挖面水平位移、地表沉降、坑底隆起、土钉轴力的有利影响范围分别约为1.3、1、1、1.2倍的开挖深度。经与实际工程现场实测值对比,验证了该模型分析结果的可靠性,同时分析结果优于平面二维和局部三维有限元模型,结论为复合土钉支护结构的优化设计和安全施工提供了理论依据和研究方法。     

Corner detection based on evolution difference of plannar curves in B spline scale space

In order to improve image corner detection precision and efficiency, a novel corner detection algorithm based on B spline scale space evolution difference is proposed. The norm of DoB is defined as corner response function to evaluate the multi scale evolution difference. The DoB corner detector confluents the image boundary features with different scales, which can not only strengthen the response of the feature points, but also depress the influence of noise. Among all corner detection algorithms based on B Spline, the proposed algorithm is relatively lower for computation complexity and faster. The comparative experiments demonstrate that the proposed algorithm works well for localization, robustness against noise, as well as invariance to rotation and scalability.     

BEHAVIOR OF THE REINFORCED CONCRETE FRAME CORNER JOINTS SUBJECTED TO CLOSING LOADS

In this paper, experimental results on the tests of 15 full-scale reinforces concrete frame corner joints subjected to closing loads arereported. The primary variables are the compressive strength of eoncrete, thesteel ratio and the ratius of main bar bend. In order to investigate the stressdistributiens of the concrete in the cores of the joints, a nonlinear finiteelement analysis of the frame corner jonts is carried out. Possible damage andfailure modes of the frame corner joints are discussed herein. Based on observedand computed results, the formulae in terms of the steel ratio and the ratius ofmain bar bend and the corresponding useful recommendations are made for thedesign of the frame corner joints.     

机械通风死角的检查与处理

粮食储藏中机械通风技术应用较普遍，但如果通风不均匀而形成通风死角，会影响粮食的安全储藏，本文就机械通风死角的检查与处理方法略述如下。     

Corner Point Detection Based on Adaptive Line Approximation

The detection of corner points is one of the basic problems of computer vision. Usually the key question of detecting corner points is how to calculate curvature. This paper presents a novel approach of calculating the backward and forward direction of reference point based on the adaptive line approximation. Our line approximation method objects minimize the distance error and the length of approximation widow adaptively changes with the approximation error. Our adaptive method finds a compromise between the length of approximation widow and the calculation precise. The experiments results show, the method can robustly, effectively and precisely locate corner point for curves with apparent corners with little computation.     

The Corner Point Processing and Absorbing Boundary Conditions in Finite-Difference Time-Domain

ABC(Absorbing Boundary Conditions) is an important component part in FDTD(Finite-Difference Time-Domain) method,the processing of corner point affect ABC itself,that is,the inadequate processing of them may cause unnaturally results.The processing of corner points in traditional second-order absorbing boundary condition for 2D case is complex,and it is difficult to extend to 3D case.For these reasons,a simpler method about the corner points based on unidirectional out traveling wave absorbing theorem is discussed in this paper,and validated by a numerical method proposed by authors.The results show that this method satisfies the demands for ABC and is more efficient and more precise.Meanwhile,it is easy to extent to 3D case.     

3D BE Analysis on Stress Intensity Factor of a Fatigue Crack in a Welded T-joint

In this paper, based on multi region boundary element method (BEM), a general procedure to calculate stress intensity factors(SIF) of a 3D mixed mode fatigue surface crack is detailed. A BEM model for a welded T joint is constructed referring to the test specimen. The crack corner points are indirectly estimated to circumvent the treatment of the different crack tip singularity at the corner regions. Numerical results from the welded T joint show that this procedure is reliable.     

折线型屋架平房仓不同部位温度变化研究

通过对仓房仓顶内外、仓房南面和西面仓墙内外及仓内西南、东北角及正中间和粮堆表上层等部位安装数字式测温电缆,经过10个多月的跟踪检测,初步摸清了环境温度对折线型屋架平房仓及储粮表上层的影响情况。     

多尺度积角点检测和视觉颜色特征的鲁棒车牌定位算法

为解决生鲜产品配送过程中的质量控制问题,将质量功能展开(QFD)与计划-实施-检查-处理(PDCA)循环相结合,运用QFD获得生鲜产品配送质量控制的关键指标,针对关键控制指标,将PDCA循环模型运用到预防措施和纠偏措施的制定和持续改进中,为生鲜产品配送中的质量控制提供指导,从而保证生鲜产品的质量。     

Determination Method and Criterion for Voids by Dynamic Deflection Difference in the Same Cement Slab

Aiming at the lack of the current determination method for voids in practical engineering applications, in order to accurately quantify the voids beneath cement slab, the determination method was proposed with slab edge slab center deflection difference and slab corner slab center deflection difference in the same cement slab for voids.Three dimensional models were set up using the ANSYS finite element method for voids beneath slab corner and slab edge.And the load was simulated with FWD test results.Thereafter, the deflection values were calculated in slab center, slab corner, slab edge under different void depth, void area and load transfer capacity.And the range of deflection diffidence was obtained.With Yantai Weihai expressway, detection data for deflection using Falling Weight Deflectometer were statistically analyzed.And the criteria and correction factors of load transfer capacity were given with simulation and samples analysis.The feasibility of criteria was verified by actual test data.It is found that the simulation values and the test values are in good agreement.The accuracy of void determination by lab edge slab center deflection difference and slab corner slab center deflection difference are 88.5% and 84.6%, respectively, which meet the engineering requirements.The voids were determined under the same conditions with the elimination of deflection variability.     

白榆新品种‘阳光女孩’嫁接繁育技术研究

为了探索白榆品种‘阳光女孩’嫁接繁育方法,同时对嫁接方法不同造成嫁接部位留下拐角的问题进行研究,试验选用地径0.6 cm白榆为砧木,设计L₉(3³)正交试验,结果表明：嫁接繁育的最佳处理是选取1年生枝条中部作为接穗,在4月上旬进行切接;芽接方法可有效地避免形成拐角苗木,成活率80.2%;切接方法中采用留接穗上靠近接口最近的内侧芽也可有效克服拐角现象,提高植株主干通直度,保证其较高的生长量,成活率可达86.9%,高于芽接。     

The Experiment of Prevention Accumulated Methane by Means of Abnormal Y Pattern Ventilation Method

In this paper, according to the experiment of abnormal Y pattern ventilation method in Coal Face 22160, Mine 10, Pingdingshan Coal Group Ltd. Co. , it is discussed that the effect of ventilation method on fugitive air and gas emission. It is discovered that Y pattern ventilation method can not only decrease air break in mine goaf by means of declining intake air in drawing road, and alleviate gas emission in gob area, but also wash the accumulated methane in upper corner by means of fresh air in middle road, and reduce the gradient of gas concentration greatly in direction of dip in upper half part of mining face and the gas concentration in upper corner. That can effectively prevent gas accumulation in mechanized high gas faces and provide reliable guarantee for high production and high effectiveness in mechanized high gas faces.     

Improvements on the Boundary Element Method( I )

This paper presents an improved BEM, which is free of singular integrals and corner problems. The numerical accuracy is also efficiently improved by this method.     

板坯连铸结晶器内凝固坯壳的三维数值模拟

基于流场和温度场的计算,对断面为1 780 mm×225 mm的板坯结晶器进行数值模拟,考虑3种不同水口条件下,钢液流动对凝固壳的冲刷,计算出凝固壳厚度的三维分布特征,并与二维切片法的计算结果进行了对比。结果表明：有水口时结晶器角部位置凝固壳最大值为约45 mm,宽面和窄面中心凝固厚度壳最大值为24 mm,分别比无水口条件下凝固壳薄1~2 mm;钢液的扩散会使凝固壳在距离结晶器角部300 mm和顶部400 mm的位置形成约深度2.5 mm的凹陷;同时钢液会冲刷整个结晶器窄面的凝固壳,在窄面中心最严重;对比不同的水口,凸底水口冲刷最大,凹底最小。     

A New Spline Boundary Element Method

This paper introduces a New Spline Boundary Element Method, which neither has corner problems and singular integrals nor involves extreme-conditions of spline function. Three numerical examples are given to show the validity of the method.     

逻辑思维在“三农”问题研究中的应用

逻辑思维是学术研究的基石,研究者应掌握基本的逻辑方法。本文在对逻辑学基础理论知识进行梳理的基础上,就逻辑思维在“三农”问题研究中的实际应用简明扼要地进行了分析。     

THE SPLINE BOUNDARY ELEMENT METHOD FOR CALCULATION OF ELECTROMAGNETIC FIELD PROBLEMS

The spline boundary element method is presented for electromagnetic field problems. Based on B-spline function interpolation, the formulation of calculation of two dimensional statical electromagnetic field problems is obtained. Boundary corner and singular integration problems are efficiently handled. Furthermore,the Method is used for solving two calculation examples.     

卧式风道环流熏蒸技术的研究与应用

采用卧式风道进行环流熏蒸能促进PH3气体在风道死角区的分布，杀虫效果好。只需一台风机，熏蒸结束拆除装置，不影响仓房结构，可节省风机及其配置费用。     

高大平房仓立体机械通风技术研究

为解决高大平房仓机械通风不均匀等问题，在原有平面通风道的基础上，于粮堆中增设相应数量的直竖式通气竹笼，使之形成粮堆立体通风网络。试验表明：可提高通风效果和均匀度，消除死角，加快降温速度，缩短通风时间，节约费用，为立体通风提供一条新途径。     

The Mode and Vibration Response of the Double Involute Gear

From the mathematical model of the double involute gear teeth surface at any corner position,we establish the model of the double involute gear with high precision and parameter in Pro/E,analyze and calculate the influence of natural frequency by the parameter of the double involute gear,analyze the frequency respond elementary.The conclusions reflect the gear's performance of dynamics,and provide the librate characteristic data for the design of double involute gear.