索承式桥梁吊索钢丝腐蚀疲劳寿命评估

根据吊索镀锌钢丝腐蚀疲劳破坏特点,把镀锌钢丝腐蚀疲劳纹形成和扩展过程分解成镀锌层腐蚀失效、蚀坑萌生、蚀坑形成、短裂纹扩展、长裂纹扩展和断裂破坏等阶段,建立各阶段时间表达式,得到镀锌钢丝疲劳寿命表达式,提出基于断裂力学的吊索钢丝腐蚀疲劳寿命评估研究结果方法。通过算例分析复杂运营条件下腐蚀环境和应力幅等因素对吊索钢丝腐蚀疲劳寿命的影响,研究结果表明：吊索钢丝腐蚀疲劳寿命主要由钢丝镀锌层腐蚀、蚀坑发展和短裂纹扩展等3个阶段组成,为了准确地评估吊索腐蚀疲劳寿命,需要掌握大桥的运营环境和交通荷载。     

高速铁路隧道基底软岩动力累积损伤特性

利用相似材料模拟高速铁路隧道基底软岩,采用荷载控制和非对称正弦波循环加载方式对软岩试件进行动三轴疲劳与损伤检测综合试验。通过试验结果分析,建立了软岩3参数多项式疲劳寿命计算模型和4参数多项式累积损伤参量计算模型,获得了软岩疲劳损伤特性,即：软岩疲劳破坏表现为端部拉-剪复合破坏和中部压-剪复合破坏两种模式;疲劳破坏全过程表现为初始微孔隙压密、裂纹发生与稳定扩展以及损伤裂纹加速发展3个发展阶段;软岩疲劳寿命主要取决于本身强度和动应力水平,强度愈高、动力应力水平愈低,其疲劳寿命就越长;当动应力水平相同时,软岩疲劳寿命与其弹性模量呈线性增长关系。     

Effect of welding on high strain and low cycle fatigue behavior of hot-rolled H-beam

Low cycle fatigue(LCF)properties of H-beam as hot-rolled and welded are studied, and the cyclic stress-strain relationship and cyclic response characterization are determined. Based on the Coffin-Manson formula, the strain-fatigue life relationship is obtained. Finally, the cyclic toughness, which is the product of strain range at LCF life of 100 cycles and the stress amplitude, are calculated. The test results show that the cyclic toughness as welded H-beam is 62% of that as hot-rolled. Hot-rolled materials exhibit cyclic stability, and welded materials show cyclic softening followed by fracture. The scanning electron microscope(SEM) micrograph of fracture surfaces reveals that the fatigue crack initiates from the coarse grain area of welding joint, and the fine dimple is observed in the fracture surface, which indicates the welding joint remains a good ductility.     

A FRACTURE MECHANICS ANALYSIS OF FRACTURE PLANE CONTROL IN FRACTURE CONTROL BLASTING

A procedure of fracture control blasting for achieving directional breaking of rocks by blasting is presented. The criterion for initiating of radial cracks in borehole wall under dynamic load and the method for determining the permissible rang of initial gas pressure (p0) in the charge cavity are developed .and the branching of radial cracks and the effeets of the pressure (p0) and blasthole geometry (R0.a.L3) on final dimensions of directed cracks are studied .with Fracture Mechanics analysis in all three aspects of fracture process including crack initiation .crack propagation and crack arrest.     

Analysis of I/O Component of ICT Control Software Based COM

To implement the reuse of industrial CT control software, make the product easily maintained and upgraded, the control software of industrial CT based COM is researched. With the characteristics of language irrelevancy, reuse of binary codes, expansion, the industrial CT control software are divided into several components according to the control function of industrial CT, and the I/O component is developed. Better effects and open characteristic are achieved while this component is communicating with the Client program.     

Statistical Analysis on High Strain and Low Cycle Fatigue Life of Rebars

High strain and low cycle fatigue(HSLCF)life of anti-seismic behaviors of rebars was investigaoted. Reliable theoretical basis was provided for data analysis on high strain and low cycle fatigue life of anti-seismic behaviors of rebars. The low cycle fatigue life of the HRB400 anti-seismic behaviors of rebars by quenching and self tempering (QST) process was tested. Because the low cycle fatigue life data was disperse, some kinds of mathematical statistics methods, such as Weibull double parameters probability function, normal distribution, lognormal distribution function and t-distribution function were used to statistically analyze the low cycle fatigue life data. The results indicate that in all of the probability functions, the low cycle fatigue life has the highest reliability by the t-distribution function method; the low cycle fatigue life has the lowest reliability by the normal distribution method; and the low cycle fatigue life has the highest safety by Weibull maximum likelihood method.     

EFFECT OF HIGH LOADS IN THE BRIDGE LOAD SPECTRUM ON FATIGUE CRACK GROWTH OF 16 Mn STEEL

This paper studies an effect of high loads in Rayleigh distribution random load-ing on fatigue crack growth wi th 16 Mn steel compact tenion specimen,The results show that thehigh loads in the load spectrum close to service load of steel bridges accelerate crack growth and re-duce crack growth life,Lives predicted with constant amplitude da/dn data and equivalent loads arequite in agreement with test lives.     

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.     

Study on Suitability of the Glaze forExpanded Pearlite Compound Glazed Tile

Through thermal expansion coefficient determination and EPMA,this paper studied the suitability of the glaze for expanded pearlite compound glazed tile.The cause of crack formation of the glaze in the material was found.Corres ponding measures to improve the quality of the product were put forward.     

Experimental Analysis on Crack Initiation Stress and Rupture Energy of Marble Failure

Based on the marble conventional triaxial test data, the crack initiation stress and rupture energy under different confining pressures are analyzed. Results showed that the crack initiation position is gradually close to the peak strength point with the increase of the confining pressure. The location of the crack initiation occurs in 50% ~70% peak strength. The rupture energy and confining pressure are in positive linear relationship as well as the rupture energy and peak axial stress. And sudden increase of AE energy count corresponds with the crack initiation stress. AE energy count and cumulative energy increase quickly after the crack initiation position, which increase significantly in the crack initiation point. The crack initiation point of theoretical calculation is in good agreement with acoustic emission monitoring. Mogi-Coulomb criterion is in keeping with experimental results.     

Development of Movement Control System of Shoe Leather Lumen CT Instrument

A method of solving the problem of shoe leather lumen measurement in shoe CAD/CAM by industrial CT technology is introduced,X ray industrial CT technology is studied. The paper gives a rational scheme of system dispose. This scheme can be not only meet the need of shoe leather lumen measurement, but also achieve ordinary measurement. An uncomplicated and practicable movement control system are proposed also. This scheme achieves high precision of movement position without expensive direct current servo-control. A new simple method measurement is developed and accurate control of position in movement of detector data insert is achieved. The image resolving power can meet shoe leather lumen measurement.     

基于医学CT和工业CT扫描研究土壤大孔隙结构特征的区别

为探究医学CT与工业CT在土壤大孔隙特征扫描研究应用的区别,选取青海地区金露梅灌丛原状土壤样品,分别采用医学和工业2种CT对其进行扫描,通过对扫描图像的分析和处理,对比分析2种CT扫描的断层图像质量、土壤大孔隙三维图像以及孔隙度特征3个方面特征,分析2种CT研究土壤大孔隙特征的差异。研究结果表明:(1)从扫描土壤横断面图像质量来看,工业CT的图像质量要明显高于医学CT图像;(2)2种CT图像经处理堆栈出的三维图像在形态上相似,但是工业CT解析出的三维图能更好地体现出不同深度的土壤孔隙分布;(3)2种CT图像经处理得到的孔隙度,随着土壤深度的变化,其特征在整体趋势上大致相同,但工业CT能更准确地反映较深层次土壤的孔隙度。因此可以根据不同的需求选择适宜的CT。     

Fatigue Life Analysis of Gussasphalt Concrete Based on Energy Method

The fatigue resistance of Gussasphalt mixture was analyzed with energy method after four point flexural fatigue test under multiple strain levels. Through the fatigue test under multiple strain levels, the linear relationship was obtained between fatigue life and cumulative dissipated energy in log log plot. And the equation for fatigue life prediction under different strain levels was also regressed. Besides, the relation between fatigue damage and dissipated energy of Gussasphalt mixture was analyzed with Maxwell model. And with the conceptions of hysteresis loop and phase angle, it is found that the mixture with bigger phase angle has better fatigue resistance.     

System Design for Leather Cavity XCT

This paper introduces a method of solving the problem of leather cavity measurement in shoe CAD/CAM by industrial CT technology. Concentrating on peculiarity and requirement of leather cavity measurement, this paper presents a X-ray industrial CT system scheme, which not only satisfy the requirement of leather cavity measurement but also can achieve general industrial CT. measurement. The achievement on data collection system and motion control of stepping motor is emphasized.     

山西晋中地区农产品加工业发展状况分析

摘要：晋中是山西粮食、蔬菜、畜产品、干鲜果的主要产区之一, 蔬菜和畜禽产品综合产量连续多年位居山西省第一。通过分析山西晋中地区农产品加工业的发展状况,目前晋中地区农产品加工企业需要加速扩大加工规模,提高研发能力和质量管理水平来不断增加产品附加值,采用较紧密的利益联结方式带动当地农户增加收入,更好地促进晋中地区优势农产品产业化的发展。     

作物蒸散不同时空尺度模型及尺度转换方法研究进展

为了通过比较经济的成本灵活获取不同尺度的蒸散量,回顾了作物蒸散研究的历史发展,重点评述了作物蒸散不同时空尺度模型及尺度转换方法研究现状,在此基础上,预测了作物蒸散的发展趋势：以精确的点尺度作物蒸散模型为基础,结合遥感数据、数字高程模型和GIS技术建立新颖的空间插值方法,从而实现作物蒸散的空间尺度转换;通过建立精确的基于遥感数据的作物系数模型,利用基于作物系数的时间尺度转换方法,实现作物蒸散时间尺度扩展;基于上述时空尺度转换方法,建立综合性的,面向业务化运行的系统作物蒸散模型。     

Experimental Study on Flexural Toughness and Fatigue Property of Polypropylene (PP) Fiber Reinforced Cement-stabilized Macadam

By four-point bending test and fatigue test,the authors studied the flexural toughness and fatigue property of semi-rigid base course of cement-stabilized macadam with and without polypropylene(PP) fiber.Some significant data about these two kinds of material have been obtained,such as the load-deflection curves,toughness index according to the standard methods of JCI and ASTM C1018-97,the fatigue lifetime under different stress levels and the fatigue lifetime regression equation.The results show that the reinforcing effect of the PP fiber is remarkable;the bending strength,ultimate deformability,JCI toughness index,ASTM C1018-97 toughness index and fatigue life of cement-stabilized macadam with PP fiber are increased by about 10%,150%,67.7%,36.1%~79.8%,and 126%~352%,respectively,when the volume fraction of PP fiber is only 0.077%.At the same time,the authors revealed the toughness improving mechanism and the anti-fatigue mechanism of the fiber in such material based on the fracture mechanics theory.     

Association mapping identifies loci for canopy temperature under drought in diverse soybean genotypes

Drought stress is a global constraint for crop production, and improving crop tolerance to drought is of critical importance. Because transpiration cools a crop canopy, a cool canopy under drought indicates a genotype still has access to soil moisture. Because measurements of canopy temperature may be increased in scale in field environments, it is particularly attractive for large-scale, phenotypic evaluations. Our objectives were to identify genomic regions associated with canopy temperature (CT) and to identify extreme genotypes for CT. A diverse panel consisting of 345 maturity group IV soybean accessions was evaluated in three environments for CT. Within each environment CT was normalized (nCT) on a scale from 0 to 1. A set of 31,260 polymorphic single nucleotide polymorphisms (SNPs) with a minor allele frequency?≥?5% was used for association mapping of nCT. Association mapping identified 52 SNPs significantly associated with nCT, and these SNPs likely tagged 34 different genomic regions. Averaged across all environments, eight genomic regions showed significant associations with nCT. Several genes in the identified genomic regions had reported functions related to transpiration or water acquisition including root development, response to abscisic acid, water deprivation, stomatal complex morphogenesis, and signal transduction. Fifteen of the SNPs associated with nCT were coincident with SNPs for canopy wilting. Favorable alleles from significant SNPs may be an important resource for pyramiding genes, and several genotypes were identified as sources of drought-tolerant alleles that could be used in breeding programs for improving drought tolerance.     

莆田枇杷产业链的成功经验给福建省药用果树产业链发展的启示

摘　 要：本文通过分析莆田枇杷产业链的发展的成功经验,提出发展福建药用果树产业链应该向规模化、区域化和专业化的联合体生产方向发展;用精深加工来延长此产业链;产品可以鲜食、保健品和药品等多种形式销售;产业链的形成、发展和延伸,带动相关产业的发展,从而实现产业效益、社会效益和经济效益的提高。     

Influence Factors on Wind induced Fatigue Life of Steel Circular Antenna with Asymmetric Brace

Wind induced responses of a single steel circular antenna with an asymmetric brace were computed considering wind speed and direction joint distribution function at location of the structure, and then wind induced fatigue life of the structure was estimated in frequency domain and time domain, respectively. Some parameters, including wind direction, surface roughness, vortex induced resonance and mean wind speed, which would have effects on the wind induced fatigue life of the structure,were discussed. It is found that 1) wind direction has great effects on wind induced fatigue damage, that is, significant fatigue can occur in wind direction of high probability; 2) the more roughness the surface of structure is, the shorter the wind induced fatigue life is; 3) the effects of vortex resonance on wind induced fatigue life should not be neglected; 4) the mean velocity has slight impact on the wind induced fatigue life of the structure.