CFD方法在压水堆安全分析中的应用现状和发展趋势

为更好地利用CFD方法解决压水堆安全分析问题,简要介绍CFD方法,着重阐述其在硼稀释、混合和热分层以及受压热冲击等压水堆安全分析问题的应用现状,并提出CFD与系统程序的耦合计算、流固耦合计算和CFD与中子动力学程序的耦合计算将是CFD方法在该领域的发展重点.     

我国内陆核电发展过程中水资源安全相关问题

核电作为一种清洁能源,在我国的能源结构调整和节能减排中起着举足轻重的作用,但其潜在的放射性污染会对水资源安全构成一定的威胁。由于自然环境和社会因素的巨大差异,内陆核电的水资源安全问题更加凸显。在简要介绍了核电站运行原理及安全设计后,阐述了国外内陆核电的状况。从放射性液态流出物污染、冷却水污染和硼污染三方面分析了内陆核电站运行对水资源安全的影响以及我国的控制措施。从水资源管理思路、水资源论证深度、水资源应急响应机制三个方面论述了我国内陆核电水资源管理中亟待加强的方面。     

Precipitation and control of BN inclusions in 42CrMo steel and their effect on machinability

The precipitation and control of boron nitrogen （BN） inclusions in 42CrMo steel were investigated and their effect on machinability was analyzed. First, the precipitation regularity of BN in 42CrMo steel was studied by theoretical calculation. Then, the machinability of the steel was investigated through contrast cutting experiments, and the composition and cooling rate of the steel were controlled to analyze the variation laws of the size, distribution, and area ratio of BN inclusions. Finally, the results were combined with the machinability of the steel to analyze the relationship among them. It is found that the machinability of the steel is mainly influenced by the diameter and quantity of BN inclusions. Fine and dispersedly distributed BN inclusions are more beneficial for the improvement in machinability of 42CrMo steel than coarse and sparse BN inclusions.     

硼掺合料对水泥浆体性能的影响

研究了不同含硼添加剂对水泥浆体凝结时间、抗压强度、抗折强度、结合水含量及碱度的影响,并采用XRD和SEM测试手段分析了硬化浆体微观结构,着重考察了硼元素的引入方式对水泥水化性能的影响。研究表明:硼砂、硼酐及硼玻璃粉对水泥浆体性能的影响存在很大差异。硼砂具有明显的缓凝作用;硼酐稍延缓了水泥的凝结时间,但严重影响了水泥石的力学性能,主要可能是硼酐中可溶性硼与水泥水化后的钙离子形成致密的水化硼酸钙膜,覆盖在水泥颗粒表面,阻止了水泥颗粒与外部溶液的接触,使水泥水化反应无法正常进行;而硼玻璃粉对水泥的凝结时间和力学性能均不存在不良影响。     

甲酸浓缩提纯新方法及应用研究

文章介绍了低浓度甲酸浓缩提纯方法———硼矸提纯法,克服了甲酸与水共沸而产生的分离难题,提纯后的甲酸浓度达93%以上,可替代试剂甲酸应用于分析检测,在节能降耗、降低测试成本和环境保护方面都具有实际意义。     

B4C/Ni多孔复合材料的制备及性能

采用粉末冶金法制备了B4C/Ni多孔复合材料。对制得的试样进行了扫描电镜（SEM）观察和抗压强度的测试，并摘要计算得出了试样的孔隙度。分析结果表明，复合材料的孔隙度随烧结温度的升高而下降；抗压强度随孔隙度的下降而增大；并且复合材料中镍含量越高材料抗压强度越大。根据后续浸渗金属液体的要求，此多孔复合材料要达到高孔隙度、较高强度和较高硼含量等指标。所以综合分析结果和后续要求最终确定了最佳体积百分含量为碳化硼15%、镍55%、造孔剂碳酸钠30%和最佳烧结温度800℃。     

New approach in depositing thick, layered cubic boron nitride coatings by oxygen addition—structural and compositional analysis

Cubic boron nitride (c-BN) can be produced by PVD and PA-CVD techniques by intensive ion bombardment leading to highly stressed films limiting its use in industrial applications. Various attempts have been undertaken to reduce the compressive stress of c-BN thin films. A significant reduction in compressive stress and a substantially improved adhesion was achieved by a new coating concept consisting of a two-step adhesion-promoting base layer, a compositional-graded nucleation layer obtained by a stepwise decrease of the oxygen content in the Ar/N₂/O₂ atmosphere and a low-stressed c-BN:O top layer with controlled oxygen addition. The four-layer c-BN:O film with a thickness of 3 μm was deposited by unbalanced radio frequency magnetron sputtering of a hot-pressed hexagonal boron nitride target on silicon substrates. The adhesion layer was deposited in a mixed Ar/O₂ atmosphere of 0.26 Pa with a stepwise increased nitrogen gas flow and a subsequent increase of the ion energy by increasing the substrate bias from 0 to − 250 V. The c-BN nucleation was gradually initiated by decreasing the O₂ gas flow. The present study was focused on the investigation of the morphology, the microstructure on the nanoscale, and the bonding structure using scanning electron microscopy (SEM), Fourier-Transmission infra-red spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) employing analytical scanning transmission electron microscopy (ASTEM). The HRTEM images revealed a four-layer coating consisting of a gradual nucleation of t-BN, on which a gradual nucleation of c-BN was achieved by decreasing the oxygen gas flow.     

高硼铸钢衬板的组织和性能

针对高锰钢衬板初始硬度低,在中、小型球磨机的工况条件下不能充分发挥加工硬化效应的情况,研制了高硼铸钢衬板。该衬板是在低碳钢中加入硼合金元素的同时添加少量其他合金元素,可以获得一定数量的高硬度Fe2B化合物,基体是强韧性好的板条马氏体,综合力学性能与耐磨性良好,硬度大于58 HRC,冲击韧性大于12 J/cm2,适用于小能量多冲击的凿削磨损型工况条件。用于替代高锰钢制造球磨机衬板,寿命比高锰钢提高2倍以上,且价格相当,经济效益好。     

极谱法测定硼的应用研究

提出了几种物料中0.0×%~×%范围内硼的极谱分析方法,所拟方法快速简便,效果良好。