非稠合型硼烷和碳硼烷的新电子计数规则

有许多非稠合型闭式硼烷和碳硼烷无法应用Wang和Schleyer的6m＋2n电子规则。作者根据实验事实和量子化学计算结果,提出了一个适用于非稠合型硼烷和碳硼烷的电子计数新规则,它适用于各种类型非稠合型闭式硼烷和碳硼烷,扩展了6m＋2n电子规则的应用范围。同时该规则对于非稠合型非闭式硼烷和碳硼烷也完全适用,应用范围比Wade规则要广。新计数规则的计算结果非常令人满意。由作者提出的新电子计数规则表明,非稠合型硼烷和碳硼烷是由一些单锥体和骨架连接键稠合而成的,而稠合型硼烷或碳硼烷则不属于该规则的讨论范畴,可仍按Tang和Li的硼烷规则计算。     

非稠合型硼烷和碳硼烷的新电子计数规则

有许多非稠合型闭式硼烷和碳硼烷无法应用Wang和Schleyer的6m+2n电子规则.作者根据实验事实和量子化学计算结果,提出了一个适用于非稠合型硼烷和碳硼烷的电子计数新规则,它适用于各种类型非稠合型闭式硼烷和碳硼烷,扩展了6m+2n电子规则的应用范围.同时该规则对于非稠合型非闭式硼烷和碳硼烷也完全适用,应用范围比Wa...     

碳硼化合物的晶体结构

在研究了大量国外资料基础上,综述了碳硼化合物的特性和优良性能,及国内外发展情况。系统概述了碳硼化合物的晶体结构,给出了碳化硼相图,指出了尚待查清的有关问题。     

中碳铬锰硅铸钢加硼后的组织和性能变化

本文分析了微量硼加入中碳铬锰硅铸钢中所引起的组织形态，机械性能和耐磨性能的变化情况，探讨了热处理规范对硼碳化合物析出形式的影响，文章在实验的基础上，得出了相应的结论。     

粉末固体碳硼共渗的试验研究

对粉末固体碳硼共渗的渗剂成份、共渗效果进行了试验研究，并探讨了共渗层组成及相结构。通过与渗碳、渗硼的对比实验发现．碳硼共渗既有较高的表面硬度，又有合理的硬度梯度而且耐磨性远远高于普通渗碳件。     

交流电场作用下的中低碳钢低温粉末法渗硼

以低碳20钢、中碳45钢为渗扩对象进行交流电场作用下的低温粉末法渗硼,对渗硼层厚度、显徽组织、相结构及硬度进行观测分析.试验结果表明:在600℃、4h保温条件下,20钢、45钢经交流电场增强渗硼获得的渗硼层厚度远远大于常规渗硼得到的渗层厚度;在交流电场作用下,渗层厚度随渗剂中硼铁含量的增加而快速增加;硼铁含量小于等于10％时,渗硼层基本由Fe2B单相构成;而硼铁含量大于等于15％时,渗硼层则由FeB+ Fe2B两相构成.对交流电场在渗硼中的作用机制进行了初步分析.     

钢的低温渗硼剂的研制

在经过初步选择渗剂的基础上,采用正交试验优化选择研制了低温渗硼剂的最佳配方.通过金相分析、显微硬度测定等实验,分析了低温渗硼层的显微组织、硬度分布.结果表明,正交试验能有效减少试验次数,获得最佳渗剂配方;该低温渗硼剂能较好地实现低温渗硼,渗硼层呈梳齿状,致密、疏松孔洞少,硼化物前沿没有明显的过渡区,也无明显的富碳区;渗硼层显微硬度梯度比较平缓,渗层与基体结合较好.     

60Si2MnREB弹簧钢中的碳硼化相的研究

使用X射线衍射和电子探针微区分析方法对60Si2MnREB弹簧钢中的碳硼相进行了综合分析.当样品中的硼含量超过0.003%,在850℃淬火后,沿奥氏体晶界出现不连续的Fe23(B,C)网,使材质变脆.950℃正火后,晶界仅有少量粒状Fe3(B,C)相存在.研究了这两种碳硼相的析出与转变机制.     

硼铁矿综合利用─硼精矿活化及含硼铁精矿改善烧结球团性能的机理

硼铁矿经磁选可分离为棚精矿和含硼铁精矿，硼精矿经活化焙烧可使B2O3活性大于90％，可直接用于碳碱法生产硼砂，含硼铁精矿可作添加剂改善烧结、球团的性能．硼精矿焙烧活化的主要原因是朋镁石问遂安石转化，矿物结构的变化引发的比表面积增大．烧结球团加入含硼铁精矿由于B2O3的作用使烧结球团中铁矿物晶粒长大，渣相量增大改善了固结条件，进而改善了烧结球团的性能．     

硼碳氮薄膜的内应力研究

采用射频磁控溅射技术制备出硼碳氮(BCN)薄膜。傅里叶红外吸收光谱(FTIR)测量发现样品的组成原子之间实现了原子级化合,扫描电子显微镜(SEM)测量发现样品与衬底间存在较大的内应力。样品剥落后,应力的消除使红外吸收峰向低波数移动。实验还发现,对新制备的硼碳氮薄膜进行600℃热处理能有效释放薄膜中的压应力。     

高强度钢柱高温下承载力数值计算方法

为了对建筑结构中的高强度钢柱进行抗火设计和验算,研究了高强度钢柱在高温下的极限承载力数值计算方法。考虑温度对高强度钢材力学性能的影响,对常温下钢柱极限承载力计算的逆算单元长度法进行了延伸,编制了高温下高强度钢柱极限承载力计算程序。采用编制的程序对高强度钢柱在高温下的极限承载力进行了计算,将计算结果与有限元分析结果进行了比较,发现吻合较好。分析了高强度钢柱截面上残余应力的分布模式,残余应力大小和柱的初始几何缺陷对极限承载力的影响。研究表明：延伸的逆算单元长度法可以用于高强度钢柱高温下极限承载力计算,残余应力的分布模式和大小对高温下高强度钢柱的极限承载力影响很小,而初始几何缺陷对极限承载力的影响较大。     

钢中含氮量对钢的拉拔性能的影响

进行了钢包底吹氮、底吹氮－氩和底吹氩三种精炼工艺对比试验,结果显示,钢中氮含量对钢的拉拔性能影响显著,钢的拉拔性能随钢中氮含量下降而有所改善。     

Effect of weld on design of steel moment-resisting connection reinforced with steel plates

The foreign experimental and FEM research of steel moment-resisting connection reinforced with steel plates are introduced. The effect of weld on the connection design is studied in two ways including weld detail and geometrical detail of steel plates contrast to the reference drawing of connection design in China. The research shows that the weld plays an important role in the design of connections. The welds connecting reinforced plates and beam/ column flange and the plate geometry have direct influence on the performance of the connections reinforced with plates. The study is helpful to the application of design of steel moment-resisting connection with steel plates.     

Effect of weld on design of steel moment-resisting connection reinforced with steel plates

The foreign experimental and FEM research of steel moment-resisting connection reinforced with steel plates are introduced. The effect of weld on the connection design is studied in two ways including weld detail and geometrical detail of steel plates contrast to the reference drawing of connection design in China. The research shows that the weld plays an important role in the design of connections. The welds connecting reinforced plates and beam/column flange and the plate geometry have direct influence on the performance of the connections reinforced with plates. The study is helpful to the application of design of steel moment-resisting connection with steel plates.     

K形中心支撑钢框架的结构影响系数

通过对K形中心支撑钢框架的pushover分析,考虑不同层数对结构影响系数的影响,对6、9、12层中心支撑钢框架进行了分析,得出在不同层数下的结构影响系数,为结构影响系数的取值提供参考。     

钢骨高强混凝土柱受力性能的试验研究

通过对6根钢骨高强混凝土柱在低周反复水平荷载下的试验研究,分析了含钢率、配箍率、轴压比以及钢骨形式等因素对钢骨高强混凝土柱受力性能及抗震性能的影响,其中轴压比与钢骨形式的影响最为敏感,决定着该种构件的受力特性,分析所得的结论可为相关研究提供试验及理论分析依据.     

钢渣、粉煤灰混凝土强度特性的实验研究

通过实验着重研究和分析钢渣粒径级配分布对钢渣混凝土力学性质的影响,以及最佳级配关系;同时找出钢渣粉、粉煤灰、水泥三者之间不同组成比例,钢渣混凝土的力学属性和强度变化规律,以便求出最佳配比,从而为钢渣、粉煤灰的综合利用提供基础资料和科学依据．     

Precipitatation Behavior of FeTiP Phase in High Strength IF Steel

The influence of chemical composition and annealing parameters on the behavior of FeTiP precipitation has been investigated. With increasing Ti content the yield strength and tensile strength were reduced, and the tendency of FeTiP precipitation became more remarkable. No FeTiP precipitate was observed and the best mechanical properties have been obtained in the steel sheet, of which the atom ratio of Ti to N is approximately equal to 1. In the temperature range of 700 to 800℃ the FeTiP precipitation could appear easily. The precipitation process was suppressed when the annealing temperature was below 600℃, and the FeTiP phase was dissolved above 900℃. The FeTiP precipitates would inhibit the migration of grain boundaries during the recrystallization in certain extent, and weaken the density of {111} fiber texture, which resulted in the reduction of r value. The relationship between composition and processing parameters, as well as their influence on the mechanical properties is discussed.     

Electrochemical behavior of steel bar in electrolytes: Influence of pH value and cations

Steel bar corrosion on electrolytes and the influence of cation were investigated. Three electrolytes of Ca(OH)2, NaOH and KOH with pH levels of 12.5, 11.5, 10.5, 9.5, 8.5 were prepared, meanwhile, the methods of free corrosion potential and electrochemical impedance spectra (EIS) were used to evaluate the influence of cations on the depassivation of the steel bar in electrolytes. The experimental results indicate that the initial corrosion pH value of the steel bar is influenced by the cation in electrolyte and the influence of K+ in electrolyte is the most remarkable, followed by Na+ and Ca2+. The initial corrosion pH values are 10.5 in KOH electrolyte, 9.5 in NaOH electrolyte and lower than 8.5 in Ca(OH)2 electrolyte.     

Influence of flow control devices on metallurgical effects in a large—capacity tundish

The influence of flow control devices on metallurgical effects in large-capacity tundish has been studied carefully with elements tracing,sampling and theoretical prospecting,The results from the studies are(1) in the continuous casting of clean steel,bad control of tundish operation may deteriorate the cleanliness of steel;(2) the cleanliness of steel is deteriorated mainly at the unstady state;(3) large amount of macro inclusions come from the top slag and the refractory of tundish;(4) installing dam and weir can improve the cleanliness of steel and lighten the influence of steel fluctuation;and (5) the result of theoretical calculation suggests that the inclusions larger than the critical size of 92.6um can be floated out from the tundish bath completely.