Small-angle coherent gamma-ray scattering at 662 keV for Pb and Sn

Discrepancies between theory and experiment have been reported in the small-momentum-transfer region x < 10 Å⁻¹ for the coherent scattering of moderate-energy photons. In the present experiment an investigation has been made of the performance of each of the primary components of an annular target setup, arranged for 662 keV photon scattering at angles in the range 5°–15°. The conventional double-cone primary-beam stop is found to significantly degrade the full-energy peak-to-valley ratio compared to that obtained with a parallel-sided arrangement. Asymmetry has been found in the response of the detector to an auxiliary point source radially distributed over the scattering plane. Appropriate experimental procedures and corrections have been adopted in obtaining differential cross sections of reduced uncertainty. Results obtained on the basis of present measurements are found to be in accordance with theory. A reanalysis of an earlier set of experimentally determined differential cross sections has been produced.     

High temperature deformation behavior of Ti−6Al−4V alloy with and equiaxed microstructure: a neural networks analysis

The hot deformation behavior of Ti−6Al−4V alloy with an equiaxed microstructure was investigated by means of Artificial Neural Networks (ANN). The flow stress data for the ANN model training was obtained from compression tests performed on a thermo-mechanical simulator over a wide range of temperature (from 700°C to 1100°C) with strain rates of 0.0001 s⁻¹ to 100 s⁻¹ and true strains of 0.1 to 0.6. It was found that the trained neural network could reliably predict flow stress for unseen data. Workability was evaluated by means of processing maps with respect to strain, strain rate, and temperature. Processing maps were constructed at different strains by utilizing the flow stress predicted by the model at finer intervals of strain rates and temperatures. The specimen failures at various instances were predicted and confirmed by experiments. The results establish that artificial neural networks can be effectively used for generating a more reliable processing map for industrial applications. A graphical user interface was designed for ease of use of the model.     

Acute gastrointestinal bleeding

Diagnosis and intervention in pediatric GI bleeding is the shared responsibility of pediatric endoscopists, radiologists, and surgeons. Brisk hemorrhage, though alarming, is most often self-limited; few cases require urgent surgery before diagnostic evaluation is accomplished. The choice between endoscopic and radiographic evaluation varies with the differential diagnoses being considered and with local referral patterns. Many imaging options exist for assessing GI bleeding in children, but these options are generally narrowed by clinical history and age-appropriate differential possibilities.     

Compound strip method for the buckling analysis of continuous plates

A special finite strip method is developed for the analysis of linear buckling of flat plate systems that are continuous over non-rigid supports. This approach incorporates the effect of support elements in a direct stiffness methodology. The stiffness contribution of the support elements adds directly to the plate strip stiffness matrices at the element level prior to assembly. This summation of plate and support stiffness contributions forms a substructure, which is termed a compound strip. The compound strip methodology may be readily employed for the enhancement of computer programs based on traditional finite strip procedures. The validity of the compound strip method for elastic buckling analysis is demonstrated in two examples. The critical loads based on compound strip methodology compare favorably with those obtained with the finite element method.     

新型8字形自承式电(光)缆护套挤出模具的设计

在 8字形自承式电 (光 )缆护套挤出过程中 ,常会出现包覆不紧密、护套偏心和厚度不均匀等问题 ,为了提高护套挤出质量 ,本文介绍了一种新型 8字形护套挤出模具。     

安棚深层系低渗透储层产能预测方法及应用

安棚深层系属典型的低孔隙度、低渗透率砂岩地层,储层自然产能低.针对该区措施后能否具有产能的有效储层的界限难以确定,研究了区域组合测井曲线响应特征,并根据地区经验、统计规律的地区适用性考察结果,优选了声波时差曲线、深浅侧向电阻率曲线差异、深侧向微球电阻率曲线差异以及RAD系数等4个测井特征参数,同时根据单井工业油流的标准和该区压裂改造层有效厚度的统计,把压裂后储层产能按产液量分为0～0.63 t/(d·m)和大于0.63 t/(d·m)的A和B的2个级别.用概率神经网络建立了适合该区的产能分级预测模型,预测模型中的产能级别与工业油流的下限值相联系,对该区10个层进行了检验,预测效果良好.