Benchmark experiment of large-angle scattering reaction cross section of iron at 14 MeV using two shadow bars – Comparison of experimental results with ENDF/B-VIII –

ABSTRACT

It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV.     

海月构造带东三段滩坝砂分布及成藏主控因素分析

辽河滩海地区海月构造带东三段沉积期,三角洲前缘砂体受湖岸流和波浪的改造,形成了一系列滩坝砂沉积,细分为滩砂和坝砂,水动力强则形成坝砂,水动力弱则形成滩砂;滩坝砂平行于湖岸线呈带状分布,易于形成岩性圈闭。滩坝砂受砂体发育规模、储层物性、断裂输导体系及封堵性等多种因素控制,在滩坝砂较为发育的东三下段,靠近海南断层、盖州滩断层且封堵条件优越的滩坝砂最易于成藏。     

Bearing capacity of horizontally layered geosynthetic reinforced stone columns

In very soft soils, the bearing capacity of stone columns may not improve significantly due to very low confinement of the surrounding soil. Therefore, they may be reinforced with geosynthetics by using vertical encasement or horizontal layers. Very limited studies exist on horizontally reinforced stone columns (HRSCs). In this research, some large body laboratory tests have been performed on horizontally reinforced stone columns with diameters of 60, 80, and 100?mm and groups of stone columns with 60?mm diameter. Results show that the bearing capacity of stone columns increases by using horizontally reinforcing layers. Also, they reduce lateral bulging of stone columns by their frictional and interlocking effects with stone column aggregates. Finally, numerical analyses were carried out to study main affecting parameters on the bearing capacity of HRSCs. Numerical analysis results show that the bearing capacity increases considerably with increasing the number of horizontal layers and decreasing space between layers.     

二里河铅锌矿井下支护方案综述

为总结出一套适合矿山实际的支护方案，二里河铅锌矿在矿山生产的20余年里，引进了多种支护工艺进行试验。矿山根据井巷、硐室所处工程环境，确定了锚杆、钢筋、钢架、混凝土进行单一或组合支护的方案，特别是千枚岩内12.4 m跨度的提升机硐室支护方式与参数，对矿山软弱岩层大跨度硐室工程支护具有参考价值。采场则按照急倾斜、缓倾斜矿体上盘千枚岩支护为例，分别列举了锚杆、锚杆+锚索支护的工程方案。采场联络巷、矿房行人通道等区域利用支柱+横梁临时支护。不但提高了采场作业安全性，也使采矿损失率降低5%，贫化率降低7%。     

液压加固补贴对破漏套管的仿真研究

针对胜利油田长距离套管损坏井连续破漏及管体刺漏等套管失效工况,以∅139.7 mm×7.72 mm的N80套管为例,借助于ABAQUS有限元软件建立了破漏套管经液压加固补贴后的有限元模型,并对套管组合体模型的承载极限进行了定量分析。研究结果表明:破漏套管表面裂缝的存在对套管组合体承受外挤工况的影响较大,而对组合体承受轴向拉力、轴向压力以及内压等工况的影响甚微;当破漏套管最小裂缝宽度小于2.5 mm时,经液压加固补贴后的组合体在轴向拉力、轴向压力、内压以及外挤等4种载荷工况下的承载极限均高于无损套管的承载极限,满足现场工况要求;而当最小裂缝宽度大于6.5 mm时,补贴后的套管组合体承受的极限外挤载荷小于63.4 MPa,抵抗极限外挤的能力有所降低;通过更改补贴管材质,可明显提高补贴组合体在内压及外挤工况下的极限承载能力。研究结果对现场施工作业具有一定的指导作用。     

厚煤层掘锚一体机快速成巷技术工艺研究

为了解决厚煤层顺槽巷道单进水平低、成巷速度慢的问题,以高河能源E2311工作面胶带顺槽掘进施工为背景,分析了JOY-12CM30型掘锚一体机在不同地质条件下的掘巷施工工艺,并确定了巷道支护参数及劳动组织方式。经现场试验,巷道掘进效率提高133.3%,矿井采掘衔接紧张局面得到缓解。     

高强不锈钢绞线网与ECC黏结-滑移关系模型

高强不锈钢绞线网与ECC的黏结是二者协同工作的基础，且黏结 滑移关系模型是其黏结性能的综合反映，故通过对17组51个高强不锈钢绞网增强ECC薄板试件进行单边拉拔试验，研究横向钢绞线间距、纵向钢绞线直径和相对锚固长度等因素对钢绞线网在ECC中黏结性能的影响规律。试验结果表明，横向钢绞线的设置可使黏结破坏由脆性破坏转变为延性破坏；高强不锈钢绞线网与ECC的黏结滑移曲线可分为5个阶段，分别为上升段、微降段、延性强化段、下降段和残余段。基于试验结果，对钢绞线网在ECC中的黏结破坏特征和黏结 滑移机理进行分析，在相关黏结-滑移关系模型的基础上，提出钢绞线网与ECC的黏结 滑移关系模型，并进行模型参数分析。所提模型及模型参数计算公式与试验结果吻合良好，能较好地反映钢绞线网与ECC的界面黏结滑移特征。     

Fe基非晶合金增强1060铝基多层复合材料的组织与性能

采用累积叠轧焊+中间退火法复合轧制1060Al/Fe基非晶多层铝合金复合板材。利用光学显微镜、扫描电镜、X-衍射分析仪以及拉伸试验机分析Al基复合材料的微观组织结构变化、断口形貌、物相组成以及力学性能。结果表明:Fe基非晶复合材料的增强体在300 ℃中间退火过程中发生部分晶化,在累积变形轧制过程中发生破碎,并随着变形道次的增加,破碎程度随之增大;复合板前6道次的累积轧制变形出现了明显的加工软化现象,并且随着变形道次的增加,其加工软化的效果愈明显;随着累积轧制变形道次增加,Al基复合材料的力学性能发生了明显的变化,第2道次轧制变形后屈服强度与抗拉强度达到了最大值为140 MPa和156 MPa,伸长率为5.53%,达到最佳综合性能。