1Cr13不锈钢板激光弯曲数值模拟

在综合分析了材料的热物理性能和力学性能随温度变化影响的基础上,建立了板料激光弯曲成形的三维热力耦合模型.对1Cr13不锈钢钢板的激光单次扫描弯曲过程进行了数值模拟,得到了形变场、温度场以及应力场模拟结果,并对其变形过程和变形机理进行了分析.     

锻造模具钢H13的热处理及氮碳共渗

研究了H13钢的热处理和氮碳共渗工艺,指出了H13钢适宜的热处理工艺为1030％淬火＋600％回火,然后再580％氮碳共渗4．5h。表面硬度可达900HV,渗氮层深0．2mm。采用H13钢的锻造模具在应用新工艺后,其寿命可提高1倍。     

Laboratory assessment of wear on nitrided surfaces of dies for hot extrusion of aluminium

A newly designed “block-on-cylinder” wear resistance testing rig, which allows testing at higher contact pressures than conventional testing methods, was used to elucidate the effect of an iron nitride compound layer (white layer) on the wear resistance of nitrided dies used for hot extrusion of aluminium (Al). The tested dies (AISI H13) with various nitrided microstructures were provided by different manufacturers of equipment for plasma and gas nitriding. The wear surfaces were analysed by SEM, BEC, micrography and roughness measurements. It was found that the iron nitride compound layer is chemically more stable against hot Al in comparison to die material. Deterioration of the compound layer begins with cracking, and as a consequence, its spalling from the nitrided surface. A high thickness of the compound layer combined with a low nitriding depth leads to its earlier spalling and vice versa. Due to the increased roughness at the removal sites, accelerated chemical attack by hot Al takes place. Comparative and simultaneous testing of two nitrided samples was carried out.     

广数GSK980T车床上管道循环泵轴的加工分析

对管道循环泵轴加工时存在的问题进行了分析,并相应提出了解决方法。管道循环泵泵轴采用2Cr13不锈钢材料,加工性能差,应合理选择切削参数,采用强度较高、导热系数较大的钨钴类硬质合金机夹可转位车刀,以保证粗糙度,提高生产效率。为控制泵轴外圆径向跳动不超过0．025mm,设置了心棒巧妙装夹,并将广数980T车床的普通三爪卡盘改装成液压卡盘,车削软爪夹持面,保证机床主轴与心棒基准的统一。     

Dynamic and kinetic modeling of isotopic transient responses for CO insertion on Rh and Mn–Rh catalysts

Isotopic transient tracer techniques have been employed to study heterogeneous hydroformylation on Rh/SiO₂ and Mn–Rh/SiO₂. Pulse injection of D₂ and allowed tracing of the deuterium and CO incorporation pathway into the aldehyde product. The d₁- and d₂-propionaldehyde responses showed a double-peak, or two-hump, response to the D₂ pulse, while showed a single-hump response to the pulse. Analysis of the product responses to the D₂ pulse in CO/H₂/C₂H₄ and CO/H₂/C₂H₄/C₂H₅CHO suggests that the first hump of the d₁- and d₂-propionaldehyde responses was due to rapid H/D exchange with adsorbed propionaldehyde via enol intermediates. The decay of the second hump was due to reaction of adsorbed acyl with spillover hydrogen/deuterium. The response was due to CO insertion followed by acyl hydrogenation. Compartment modeling of the product responses from the and D₂ pulse inputs allowed determination of residence times of adsorbed intermediates, surface coverages of adsorbed intermediates, and the elementary rate constants for acyl hydrogenation and CO insertion. Elementary rate constants for acyl hydrogenation determined from this study were consistent with the value calculated by transition state theory (TST). The addition of Mn promoter to Rh/SiO₂ increased coverages of , , and and shifted the rate-limiting step for propionaldehyde formation. Acyl hydrogenation is the rate-limiting step on Rh/SiO₂ while CO insertion and acyl hydrogenation are both kinetically significant on Mn–Rh/SiO₂.     

吡啶衍生物^13C—NMR化学位移模型研究

通过对吡啶衍生物13C－NMR化学位移与模型化合物的取代基参数的系统分析,提出了吡啶衍生物化学位移的取代基效应因子,由此得到13C-NMR化学位移经验计算公式：δ（k）＝bk＋;并以此式计算了64种吡啶衍生物的13C-NMR化学位移．计算值与文献值较为一致．还对某些化合物的化学位移进行了预测．     

强束流Zr离子注入H13钢改善其耐磨性的研究

采用由金属蒸汽真空弧（ Ｍｅｔａｌ Ｖａｐｏｒ Ｖａｃｕｕｍ Ａｒｃ） 离子源引出的强束流脉冲Ｚｒ 、Ｚｒ ＋ Ｃ 离子对Ｈ１３ 钢进行了离子束表面处理。借助划痕仪和摩擦试验机分别测量了经表面处理的Ｈ１３ 钢的耐磨性和摩擦系数。研究结果表明： 经Ｚｒ、Ｚｒ＋ Ｃ 离子束处理的Ｈ１３ 钢的耐磨性有所提高、摩擦系数明显降低。采用卢瑟福背散射谱（ 简称ＲＢＳ） 、Ｘ 射线（ 简称ＸＲＤ） 分析了注入层的成分、结构及其影响其耐磨性的因素。     

New metallic derivatives of cellulose: Compounds of microcrystalline cellulose and potassium

Potassium derivatives of cellulose were prepared by treating of microcrystalline cellulose (MCC) with complexes of potassium (K) with ethylenediamine (EDA) and K with hexamethylphosphoric triamide (HMPT). The reaction products were characterized by X-ray diffraction,¹³C-NMR and FTIR spectroscopy, SEM, and EDXA.     

核磁共振研究未知聚合物结构

利用超导核磁共振(NM R)通过测定某一未知聚合物的1H和13C谱,对该聚合物的化学位移进行了归属,确定了该聚合物的成分及其结构。     

PET心肌血流量测定

介绍了以15O-H2O和13N-NH3作为显像剂，应用PET和示踪动力学原理进行无创性局部心肌血流量（RMBF）测定的方法，并对RMBF测定中的技术问题，如输入函数校正、部分容积校正和心肌血容积校正等进行了简述