基于钻孔压水试验数据的岩体裂隙特征分析

以某隧道工程压水试验为例,利用钻孔压水试验P~Q曲线对岩体裂隙特性进行定性分析。选取该试验孔三段压水试验成果,对岩体裂隙的发育程度、张开度、填充情况及受压情况下裂隙变化状态,进行综合分析与研究,并将分析结果与钻探取芯、波速测试成果进行对比和相互验证。     

Determination of the normal horizontal working area: a new model and method

A new model was developed for the determination of the normal horizontal working area by extending Squires' concept. The elbow not only moves freely straight ahead, but also to the right and left of the operator in describing the working area. The parametric equations developed in this research enabled us to determine working area curves which lie on both sides of the body median. Experimental results showed that the relevant anthropometric parameters were poorly correlated. A new method was developed to determine correctly the normal horizontal working area curves for the 5th, 50th, and 95th percentiles of male and female populations. When compared to the corresponding curve generated by the new method, Squires' curve for the 10th percentile male considerably overestimated the normal horizontal working area to the right of the body median and underestimated it to the left.     

小型高效蒸汽轮机主汽阀的优化设计

数值模拟了某小型高效汽轮机主调阀内的全三维复杂蒸汽流场,给出了阀门的整体流量特性曲线,分析了阀门内部流场细节,指出调节阀的喉道附近流场分布不均匀是造成阀门损失的主要原因。接着对阀碟型线进行优化,优化后的阀门通流量减小,流场内部涡流区大大减小,速度分布不均匀性得到改善,湍动能范围和幅值大幅度下降,这一切表明阀门的效率和稳定性得到很大的提高。最后,实验验证了阀门的通流特性和安全性,为阀门的结构优化设计提供了重要依据。     

Fast Ray Tracing of Implicit Surfaces

A ray-tracing algorithm is described for rendering implicit surfaces formed with C¹-continuous bounded functions f ( x , y , z ). This class of functions includes such popular implicit models as blobby molecules, metaballs, soft objects and convolution surfaces. The algorithm employs analytical methods only, which makes it fast, robust, and numerically stable.
An earlier version of this work was presented at the 3rd International Workshop on Implicit Surfaces held in Seattle in 1998.     

Multiresolution Curve and Surface Representation: Reversing Subdivision Rules by Least-Squares Data Fitting

This work explores how three techniques for defining and representing curves and surfaces can be related efficiently. The techniques are subdivision, least-squares data fitting , and wavelets . We show how least-squares data fitting can be used to "reverse" a subdivision rule, how this reversal is related to wavelets, how this relationship can provide a multilevel representation, and how the decomposition/reconstruction process can be carried out in linear time and space through the use of a matrix factorization.
Some insights that this work brings forth are that the inner product used in a multiresolution analysis in uences the support of a wavelet, that wavelets can be constructed by straightforward matrix observations, and that matrix partitioning and factorization can provide alternatives to inverses or duals for building efficient decomposition and reconstruction processes. We illustrate our findings using an example curve, grey-scale image, and tensor-product surface.     

L360NB管线钢连续冷却转变(CCT)曲线的测定和冷却速度对组织的影响

用Gleeble-1500热模拟试验机测定了L360NB管线钢圆铸坯(/%:0.14C、0.32Si、0.14Mn、0.020Ti、0.010V、0.038Nb、0.040Al)的连续冷却转变(CCT)曲线,并用光学显微镜观察了0.1～50℃/s冷却速度的组织。结果表明,当冷却速度为0.1℃/s时,钢的组织主要为板条贝氏体和准多边形铁素体,有少量针状铁素体,当冷却速度≥1.0℃/s,准多边形铁素体减少,板条状贝氏体和针状铁素体增加;当冷却速度≥10℃/s时试样的组织主要为板条状贝氏体和针状铁素体,准多边形铁素体很少,在50℃/s时未观察到块状准多边形铁素体,说明Nb、V、Ti复合微合金化促进贝氏体形成。     

汽车大梁用钢WL510连续冷却过程的相变和组织

通过Thermecmastor-Z热模拟试验机研究了WL510钢(/%:0.090C、0.13Si、1.45Mn、0.005S、0.019P、0.040Al、0.020Ti、0.030Nb)粗轧后板坯(36 mm×1 500 mm)在1～36℃/s连续冷却条件下的相变和组织的变化,并用热膨胀法测定了试验钢连续冷却转变(CCT)曲线。结果表明,试验钢WL510在1～23℃/s低冷却速度下,主要形成多边形铁素体和少量珠光体;当冷却速度≥30℃/s时,主要组织为细针状铁素体、少量细珠光体和岛状马氏体/奥氏体(M/A)随着冷却速度的增加,试验钢组织明显变细。     

稀土元素Ce对204Cu奥氏体不锈钢耐腐蚀性能的影响

204Cu奥氏体不锈钢(/%:0.125~0.131C,0.32~0.34Si,8.51~8.73Mn,0.002~0.006S,0.035~0.007P,16.40~16.64Cr,2.53~2.72Ni,2.33~2.38Cu,0.257~0.271N,0~0.064Ce)由10 kg真空感应炉熔炼,锻成25 mm×25 mm方坯,并进行1150℃ 2 h水冷的固溶处理。利用重量法和电化学法的交流阻抗和极化曲线技术研究了0~0.064%Ce对204Cu不锈钢在25℃ 3.5%NaCl溶液中耐腐蚀性能的影响。结果表明,204Cu不锈钢中加入一定量的稀土元素Ce,204Cu不锈钢的阳极极化电位值正移,降低腐蚀电流密度,增加极化电阻,可以显著提高其耐腐蚀性能,当向钢中加入0.029%Ce时,204Cu不锈钢可以获得最佳的耐腐蚀性能。     

薄板坯连铸连轧C-Si-Mn TRIP钢组织和力学性能的研究

用Gleeble-1500热/力模拟机研究了成分(%)为:0.20C-1.08Si-1.43Mn TRIP(相变诱导塑性)钢连续冷却时的组织,并测得动态CCT(连续冷却转变)曲线,得出冷却速度达10℃/s时出现粒状贝氏体,冷却速度15℃/s时得到板条贝氏体。在实验室模拟C-Si-Mn TRIP钢薄板坯连铸连轧工艺试验:用10 kg真空感应炉冶炼,成分(%)为:0.20C-1.54Si-1.55Mn的TRIP钢,钢锭尺寸为(mm):60×100×130,经7道次轧制成厚度6.40 mm板,终轧温度810℃,轧后空冷至700℃,再水冷至400℃模拟卷取。试验结果表明,该钢组织含有5.13%残余奥氏体,37.20%贝氏体,机械性能σ_b715 MPa,σ_s520 MPa,屈强比0.73,δ20%。     

兰州市经济增长与环境污染演进计量模型分析

通过对1986-2003年兰州市环境经济数据的计量模型分析,发现兰州市工业\"三废\"排放与经济增长之间的拟合曲线并不完全符合典型环境库茨涅茨曲线的特征.研究认为经济发展、产业结构变化、能源消费结构升级、政策技术及特殊的河谷型自然条件是造成兰州市非典型环境库茨涅茨曲线的主要原因.