Long multifilament Bi-2223 Ag-sheathed superconducting tapes and solenoids

Multifilament Ag-sheathed BiPbSrCaCuO (2223) superconducting tapes containing 49 filaments were fabricated by the powder-in-tube route and the roll-anneal process. The transport critical current densityJ _c was 1.3×10⁴ A cm^–2 at 77 K and 7×10⁴ A cm^–2 at 4.2 K in self-field. A 12-m-long tape was used to construct superconducting solenoids (50, 28, and 14 mm internal diameters) generating dc fields 380–1070 G at 4.2 K. Measurements of the variation ofJ _c with field (0–1.6 T) and bend strain (0–5%) are used to explain the performance of the solenoids. The critical bend strain of tapes was about 1.5%.     

粗粒土渗透变形机制浅析

对砂卵砾石的渗透变形的形成条件进行了简要分析，在此基础上对渗透变形的形式进行了简要评价，并提出了渗透变形临界坡降的计算方法。     

A new monitoring system for piping systems in fossil fired power plants

A CEC-funded project has been performed to tackle the problem of producing an advanced Life Monitoring System (LMS) which would calculate the creep and fatigue damage experienced by high temperature pipework components. Four areas were identified where existing Life Monitoring System technology could be improved:

1. 1. the inclusion of creep relaxation

2. 2. the inclusion of external loads on components

3. 3. a more accurate method of calculating thermal stresses due to temperature transients

4. 4. the inclusion of high cycle fatigue terms.

The creep relaxation problem was solved using stress reduction factors in an analytical in-elastic stress calculation. The stress reduction factors were produced for a number of common geometries and materials by means of non-linear finite element analysis. External loads were catered for by producing influence coefficients from in-elastic analysis of the particular piping system and using them to calculate bending moments at critical positions on the pipework from load and displacement measurements made at the convenient points at the pipework. The thermal stress problem was solved by producing a completely new solution based on Green's Function and Fast Fourier transforms. This allowed the thermal stress in a complex component to be calculated from simple non-intrusive thermocouple measurements made on the outside of the component. The high-cycle fatigue problem was dealt with precalculating the fatigue damage associated with standard transients and adding this damage to cumulative total when a transient occurred.

The site testing provided good practical experience and showed up problems which would not otherwise have been detected.     

聚合物降解产物伤害与糖甙键特异酶破胶技术

综述了钻井，完井，尤其是水力压裂作业中产生的多糖类聚合物伤害和应用糖甙键特异酶破胶，解除多糖类聚合物伤害的技术。第一节报道了聚合物降解产物造成的伤害，指出冻胶破胶液粘度低并不代表压裂液已从充填裂缝中充分返排，氧化破胶剂和普通酶破胶剂不能使多糖类聚合物充分降解，产生的大分子量，水不溶的降解产物可对地层造成伤害，消除伤害的办法是采用对糖甙键有特异性的各种水解酶作压裂液破胶剂或伤害地层处理剂。第二节报道了各种聚合物（纤维素，瓜尔胶，淀粉）糖甙键特异酶降解聚合物的机理。第三节报道了糖甙键特异酶（主要针对瓜尔胶）的应用性能测试及结果，包括岩心流动实验，含糖量和分子量测定，传导性测试。第四节介绍了糖甙键特异酶消除聚合物伤害和用作压裂液破胶剂的现场应用，包括选井原则，实施工艺要点及3个典型井例。     

混凝土小型砌块建筑裂缝宽度的标准设置研究

通过对混凝土小型空心砌块单片墙进行试验 ,了解不同构造措施墙体的初始裂缝在墙体上出现的部位、形态、发展规律以及墙体最终破坏形态 ,并通过试验明确墙体在不同受力状态下的裂缝形态 ,最后根据试验结果初步提出混凝土小型空心砌块建筑的裂缝宽度控制标准     

Magnetic field dependence of shielding current density in Y-Ba-Cu-O rings at 77 K

A method for contactless measurement of the shielding critical current density and its dependence on the external magnetic field is described and analyzed. The obtained values are compared with those measured resistively on two different samples. It is shown that the shielding critical current densityJ _cs and the intergranular transport current densityJ _cr are identical if the measurement conditions are similar. A degradation ofJ _cs measured in the external field with AC ripple has been observed.     

储层敏感性快速预测软件在大港油田的研究与应用

在储层特征分析，室内实验，机理研究的基础上，利用人工神经BP网络建立预测模型，并编制了预测储层5种敏感性的软件，该软件受人为因素干扰小，所需参数少，准确度高，综合符合率大于80％现场应用结果表明，该技术能为制定保护油气层技术措施提供较可靠的依据，能提高油田滚动开发效益，改善老油田的开发效果，该软件对BP算法进行了改进，（1）从两方面入手使网络摆脱平坦区，一是对输入数据进行归一化处理，使O1的取值在[0,1]之间，二是一旦网络陷入平坦区域，局部极小，使连接权值Wkj,Wji和阈值Qk,Qj同时缩小一个因子，λ＞1，可使Ok(1-Ok)脱离零值，离开平坦区；（2）加速收敛，方法有自动调整学习因子，添加动量项以及对权值进行批处理，用BP算法预测储层潜在敏感性，首先应确定影响储层敏感性的主要因素，然后根据这些因素有针对性地收集有关资料并进行处理，再根据敏感性预测的要求，设计相应的网络结构进行训练，最后对训练好的网络进行.检验。     

Deformation of Rodlike Elements of Composite Materials Subjected to Uniform Compression

On the basis of generalization of the results of investigation of the operation of rodlike elements of composite materials, we make a conclusion that the influence of various factors on the deformability of these elements is studied incompletely. The comparison of the stress-strain states for different models of concrete and reinforced-concrete elements makes it possible to describe the effect of longitudinal reinforcement (coefficient of reinforcement, strength and deformation characteristics) on the critical level of strains in the cross section. According to the results of our investigations, we give recommendations concerning the evaluation of the critical value of the coefficient of reinforcement above which one may observe the effect of reinforcement on the deformability of the analyzed sections. It is shown that the compression strength of the brittle base of the composite with inhomogeneous structure decreases as a result of the fracture processes. It is also demonstrated that the existing procedure used for the evaluation of the indicated decrease in strength requires significant improvement. The problem of evaluation of the ultimate value of the coefficient of reinforcement is also analyzed.     

WIN32线程同步方法分析与实现

文章分析了WIN32线程同步的一般方法，并提出了一种的经实践证实也是切实可行线的线程同步方法。     

大庆油田套损井打通道加固技术

介绍了大庆油田近几年在套损井打通道加固技术方面取得的技术进步，在磨铣打通道技术上主要对钻铣工具的结构进行了优化设计及合理及合金刀块的优选组合，提高了磨铣效率，缩短了施工周期；在爆炸打通道技术中设计了安全隔爆装置，提高了施工的安全性，使爆炸扩径技术得到完善；Φ106mm密封加固技术的研制成功，取代了Φ100mm密封加固技术，为套损井修复后的完井工艺提供有效的技术支持，提出了大庆油田目前在套损井打通道加固方面存在的难题，结合国外在套损井打通道加固方面技术的新发展，对现有技术的局限性进行了分析，提出了今后技术攻关的方向。