Stress Distribution in Fixed Anchor Length of Compression Type Anchor in Soft Rock Mass

To study stress distribution in fixed anchor length of compression type rock anchor cable, field test was carried out. Strain sensors were placed in the grout paste in fixed anchor length with certain interval. Axial and radial strains of the grout were noted by test. Shear stress distribution curve along the fixed anchor length was obtained by stress-strain relationship and static equilibrium analysis. Analysis results prove that maximal shear stress on the interface can achieve upper level and move forward when the load increases; the transmission length is short; shear stress transfers forward; and three dimensional state is obvious around capacity plates in soft rock mass.     

A visco elasto plastic creep model of outburstprone coal under triaxial compression

Using self made creep seepage experimental apparatus, triaxial creep tests on outburst prone coal are carried out with coal samples taken from Songzao Coal Mine. It is found that the attenuation creep property is shown in the conditions of less than its long term strength load, while non attenuation creep property for the greater conditions. By introducing a visco elasto plastic body which can describe the deformation property of non Newtonian fluids, the visco elasto plastic creep model of outburst prone coal is put forward combined with a Poyting Thomson model. The model parameters were fitted out with Matlab programmer and validation is employed. It is found that the test results were in good agreement with those by the proposed model.     

Experimental Study on Local Nonuniform Compression of Fired Shale Perforated Brick Masonry

In order to know the behavior of local nonuniform compression of fired shale perforated brick masonry with rectangular holes,the experimental study of 18 specimens with and without restriction at the end of beam under local compression was carried out.The failure modes and bearing mechanisms of specimens were researched and analyzed,the integrity coefficient of local compression stress figure was deduced,at last,the theoretical and testing values of local compression bearing capacity were compared and analyzed.The results indicate that the bearing performance at the end of wall section under local compression behaves better than that on the fringe,the vertical cracks throughout the specimen on the fringe caused by local nonuniform pressure weaken the advantageous function of 'unloading by the interior arch',the effective supporting length calculated according to code for design masonry structure is partial to safety.These results and suggestions can be used in the design of bearing perforated brick masonry for reference.     

Elasto- plastic Analysis of Pressure Circular Tunnel with Liner

According to the strain nonlinear softening constitutive model having inflexion point after peak stress of practical rock and considering intermediate principal stress, the plastic zone of circular cavern with liner under the condition of uniform pressure is analyzed. The elasto - plastic boundaries both for the lining and surrounding rock are discussed. The stress distribution law is different due to the different position of elastic - plastic boundary. Based on this, different stress formulas are gained. The critical pressure caused by excavation of cavern leading to the yield zone and that caused by inner pressure leading to the yield of the liner and surrounding rock is introduced.     

Study of Quality Management and Inspection Technology of Anchorage System

Sonoprobe method has been applied in non-destructive inspection of anchorage project. Its fundament is to cause anchor bar's elastic vibration by dynamic transient excitation and the flaws of anchor bar can be estimated or deduced by determining the transient response. The numeric solution!of hyperbolic equation by FEA indicates that the deductions should comply with the acoustic parameters such as sound velocity, vibration range, wave shape etc., when inspecting the interior flaws in grouting of anchor bar. As a non-linear dynamic system,"the artificial neural networks dealing with quality inspection of gray system have been proved efficient.     

A 3D Visco elasto plastic Finite Element Analysis of the Asphalt Pavement Rutting Deformation

Based on the dynamic action between vehicles and pavement, a simplified model of vehicle dynamic loading caused by surface evenness was established. This research made it possible to find a Asphalt Pavement Rutting Prediction method based on the theory of visco elasto plasticity which is the basic theory of the dynamics, and finite element method (FEM). Asphalt pavement rutting was calculated and predicted, and the factors influencing rutting were analyzed and calculated. The good agreement between the calculation results and the testing road data indicate that the rutting prediction method is reasonable and reliable.     

基于改进的Southern杂交法检测古树木端粒长度的研究

研究旨在利用DNA印迹法测量端粒长度从而预测植物的年龄,但木本植物体内富含黄酮类、酚类、多糖、萜类等次生代谢物质,严重影响了提取的基因组DNA产量和质量,以及后续的酶切及杂交实验结果。笔者以北京颐和园5种古树为实验材料,在传统CTAB法提取DNA基础上,不同树种分别添加2%~6%PVP,可有效去除次生代谢物质对DNA的干扰,可被限制性内切酶HinfⅠ酶切完全。同时,对DNA印迹法的其他实验参数如DNA量、曝光时间进行了优化,并进行了3种不同年龄古树端粒长度测定,结果显示古树的平均端粒长度要高于幼树,本研究建立的实验方法为多年生林木特别是古树端粒长度、树龄检测与寿命预测等提供了参考。     

Application and Test Analysis of Anti-float Anchor in Submerged Square

In this paper, based on the reconstruction project of the bar in Shekou, Shenzhen, under the action of circular loads, the ultimate bearing capacity and the stress along the anti-float anchor were tested and the change of the loading was analyzed in an in-situ test, which may be taken as reference for other similar projects with the same strata.     

Stress Analysis of Anchorage Zone on Tower of Long span Cable stayed Bridge

Anchorage zone on tower of cable stayed bridge has complex structures and stress distributions, and keeping it on a safety state under a large tonnage tension and prestress is more concerned in design and construction. The stress distribution of the anchorage zone was analyzed by 3D finite element method. Furthermore, the mechanical properties and the rules of stress distributions were investigated and compared in three different load cases. The results show that the disposition form of level prestressing tendon is reasonable. The stress of the entire tendon is very close to 1 116 MPa under the tension control stress of 1 260 MPa. It is shown that the intensity of the tendon has given full play to prestress and it is not appropriate to increase the tension control stress.     

A Context Model of Wavelet Coefficients for Image Compression

Through the combination of the idea of the linear prediction used in the GlicBawls coding scheme and the idea of the quantization taken in the CALIC coding scheme to reduce the number of contexts, a new context model of wavelet coefficients for image compression is proposed. Wavelet coefficients are encoded by the arithmetic encoder, with the contexts formed by quantizing linear prediction values. Experimental results show that the model achieves higher lossless compression rate of image than lossless SPIHT and lossless EBCOT used in JPEG2000. In addition, by exploiting the multiresolution property of wavelet, the model can compress the transformed image for progressive resolution and earn higher compression rate for each scale of the image than EBCOT.     

Analytic Solution of Anchor Bolts with Dynamic Detection

Sonoprobe method has been applied in non-destructive inspection of anchorage project. Its fundament is that to use dynamic transient excitation for inducing anchor bar's elastic vibration. The flaws in the bar can be estimated or deduced by determining transient response of anchor bar. Based on the theory of elasto-dynamics, in this paper, a theoretical model of acoustic detection of anchor bar has been built up. On the mechanics field, this method means that if information of disturbance resource, boundary conditions and initial conditions has been given, the dominant equation describing medium motion would be established. That is, it leads to the problem of initial value or initial boundary value of hyperbolic type or hyperbolic-diffusibility type equation. Thereby the dynamic response could be solved. As an example, analytic solution of heterogeneous wave equation is deduced in case of bounded region.     

Analysis of the Strength and Stability of Type CYM Hydraulic Anchor Station

The structure of type CYM hydraulic anchor station and its principle ofoperation are briefly introduccd,and its strength and stability are analyzed.     

利用染色体片段置换系定位低温影响水稻萌芽期根长和芽长QTL

根和芽的正常生长和发育对保障水稻产量有重要作用。为探究在低温条件下影响幼芽期根长和芽长的QTL,以9311（受体）和日本晴（供体）染色体片段置换系群体为材料,将萌发种子置于15℃低温处理7d,然后在25℃下恢复生长7d,连续测量根长和芽长,以25℃下根长和芽长作为对照,定位低温条件下影响根长和芽长的QTL。15℃条件下,定位到9个根长QTL,贡献率为8.65%~24.35%,其中qRL15T7.2和qRL15T10.3在根生长不同时期被重复检测到;定位到9个影响芽长的QTL,贡献率为1.73%~28.89%,其中qBL15T6、qBL15T7、qBL15T9和qBL15T10被重复检测到。25℃条件下,定位到9个根长QTL,贡献率为1.73%~28.89%,qRL25T7、qRL25T9.3、qRL25T10和qRL25T12在根生长不同时期被重复检测到;定位到5个影响芽长QTL,贡献率为0.58%~38.26%,qBL25T3.3在芽生长不同时期被重复检测到。其中,第2、7、9和10号染色体上4个Bin标记区域存在既控制根长又控制芽长的QTL。通过比较发现,15℃下定位到的根长或芽长QTL与25℃定位到的根长或芽长QTL均不相同,表明低温条件下控制水稻幼芽期根和芽生长的遗传机制可能与正常温度下不同。     

Study on Shear Stress Distribution and In-situ Test of Pressure-Dispersive Anchor

Combining the Mindlin elastic displacement solution with the elementary theory of finite element, in this paper, the shear stress distribution of pressure-dispersive anchor is calculated. Its work performances were compared with those of tensile anchor. According to the in-situ pull-out test of pressure-dispersive anchors in weak rock stratums, it is proven that the bearing capacity of pressure-dispersive anchor increases rather evidently than that of tensile anchor under the same condition and the effect of spacing between load-supporting bodies on the bearing capacity of pressure-dispersive anchor is analyzed. The analysis results of this paper can offer some references to the engineering application of this new type of anchor in the future.     

Fatigue Maintenance Probabilistic Optimization of Cable-girder Welded Anchorage Zones in Suspension Bridges

it is necessary to balance the failure risk and the maintenance expensive. A methodology for reliability based maintenance optimization of steel bridge welded joints subjected to fatigue is proposed considering linear elastic fracture mechanics (LEFM), the structure reliability, life cycle cost method and maintenance strategies. The maintenance cost is divided into inspection, repair and failure sections according to the whole life cycle cost methodology. And the maintenance strategy is transformed to the minimum expected lifetime costs with a constraint of the minimum acceptable reliability index. An case concerning to a transverse stiffener of bottom flange welded joint of Qingcaobei bridge is studied with a certain number of simplifications. Some sensitivity analysis is provided. Among all the parameters, discount rate is the most remarkable.     

棉纤维品质长度的图像测量

提出了一种新的棉纤维品质长度的检测方法。该方法主要通过使用CCD、计算机、高亮度光源构成的精准测量系统而实现,它能够准确测量Hertel曲线上任意一点的纤维累积根数。基于随机分布理论,建立了纤维长度分布的数学模型,实现了对主体长度以上纤维各个长度进行分段测量。实验表明,本方法的测量结果与Y111结果高度相关,测量速度快。     

黄瓜黄色线与瓜长比的主基因+多基因的遗传分析

选用2个性状稳定的自交系黄瓜,配成正反2个组合,测定结果表明,正反交组合黄色线与瓜长比的差异不大,表明黄色线遗传受核基因控制。应用主基因 多基因混合模型分析方法对黄瓜组合(M25×M67)的6个家系世代(P1,P2,F1,B1,B2,F2)的黄色线和瓜长比进行遗传分析。结果表明:黄色线比例遗传受1对加性-显性主基因 加性-显性多基因(D模型)控制。分离世代中,B1,B2,F2世代的主基因遗传率(h2mg)为95.8%,93.39%和14.99%;多基因遗传率(h2pg)在1.36%~54.04%。主基因加性效应(d)和显性效应(h)值分别为-41.78和-35.96。黄色线的遗传可能是受1对加性-显性主基因 加性-显性多基因控制。     

黄瓜种子长度的遗传分析及分子标记

为了今后正确制定籽用黄瓜育种方案和有效地进行品种选育,有必要对黄瓜种子大小进行详细研究。选用种子长短不同的5个黄瓜自交系作为杂交亲本,按照Griffing双列杂交试验方法Ⅱ配制杂交组合。以长种子自交系D06157和短种子自交系D0603为亲本,构建F2分离群体,采用SSR分子标记构建遗传连锁图谱,利用复合区间定位方法进行QTL定位。结果表明：黄瓜种子长度属于数量性状,以显性效应为主,同时存在加性效应,广义遗传力及狭义遗传力较低,分别为28.6777%、10.8384%。构建的4个连锁群含有16个SSR位点,连锁群总长度为287.1 cM,标记间平均距离为17.94 cM。检测出6个与黄瓜种子长度相关的QTL,其中QTL5和QTL6有着较高的对种子长度性状变异的解释率(>5%),距离最近标记的图距分别为2.1 cM、4.3 cM,LOD值分别为7.84、9.69,可解释遗传变异分别为6.07%、6.08%,加性效应值分别为39.12%、37.21%。     

Partial Pressure Problem About Continuous Rigid Frame Bridge Anchorage Zone of Thin Concrete Box Girder Webs Carrying Large Tonnage

With continuous rigid frame bridge span increasing,cantilever construction of large tonnage anchor are also becoming more common,but local stress distribution is complicated on prestressed anchorage zone of thin concrete box girder webs by the large tonnage,which reveals its distribution of post-tensioned concrete bridge structure to be solved in the future.Based on the theory,some key points such as pressure factors,destruction and the reasons for the compression type crack were discussed in the paper.By using the North Approach continuous rigid frame concrete bridge of Yangtze River Bridge project example,the local compression strength,crack resistance and the smallest protective layer thickness of the first segment of one continuous rigid frame box girder bridge under design value Rally 4882.5 kN of No.T2 tendom,according to the local pressure formulas of Code for Design of Highway Reinforced Concrete and Pre-stressed Concrete Bridges and Culverts of China(JTG D62-2004) and Finite Element Method,were checking.Both the results verify that meets the standard requirements.The results reveal that the design of a web-Laced with horizontal steel mesh sealed off side stirrup can solve the partial pressure problem.