微量元素Sr对Al—Si合金凝固过程的影响

用差热分析法系统地研究了Sr对Al-Si共晶、亚共晶及超共晶合金的动态凝固过程的影响。结果表明,Sr既可促进α-Al成核,使其初晶析出温度比二元合金中α-Al相析出温度明显提高,又能抑制初晶Si成核,使超共晶中初晶Si相析出温度较二元合金中Si的初晶的实际析出温度明显降低,还能促使共晶合金成核,使加Sr后的共晶析出温度明显提高。     

混合稀土对共晶Al-2％Fe合金组织形态的影响

研究了富La混合稀土对共晶Al-2％Fe合金组织形态的影响。当混合稀土加入量较少时，合金中的α—Al相为明显的胞状枝晶；随着混合稀土加入量的增加，α-Al枝晶优先形核生长得到抑制，共晶Al3Fe相得到细化；当稀土加入量增至0．6％(质量分数)共晶Al3Fe相尺寸逐渐增大。并对混合稀土对共晶Al-2％Fe合金组织形态的影响机制进行了探讨。     

富镧稀土对消失模铸造B319合金组织的影响

利用等离子发射光谱仪，差分扫描量热仪（DSC），电镜及金相分析等手段，研究了RE对消失模铸造B319铝合金组织的影响。结果表明，在消失模铸造条件下，0．15％RE可使B319铝合金的硅相得到较好的变质效果。但当RE＞0．2％时，会出现富稀土的粗大块状金属间化合物La3Al2Si2，而对机械性能产生不利影响。当Fe/Mn=1.2时，消失模铸造组织中存在中国文字状的α－Fe和针状β-Fe铁相以及Al2Cu相。AlCu相可以离异共晶的形式析出，β-Fe及Si相均可以作为Al2Cu相的形核基底。而在金属型铸造组织中，铁相则完全以铁状的β-Fe形式存在。研究还表明，0．02％Sr变质使B319合金共晶转变温度下降了7℃。而RE的加入会使合金的共晶温度升高，采用0．2％RE对B319合金进行变质处理，其共晶温度从570．0℃升高到了572．0℃。     

混合稀土对共晶Al-2%Fe合金组织形态的影响

研究了富La混合稀土对共晶Al-2?合金组织形态的影响. 当混合稀土加入量较少时, 合金中的α-Al相为明显的胞状枝晶;随着混合稀土加入量的增加, α-Al枝晶优先形核生长得到抑制, 共晶Al3Fe相得到细化;当稀土加入量增至0.6% (质量分数)共晶Al3Fe相尺寸逐渐增大. 并对混合稀土对共晶Al-2?合金组织形态的影响机制进行了探讨.     

电弧熔炼过程中LaFe_(13-x)Si_x合金的凝固组织和相形成研究

研究了电弧熔炼过程中LaFe13-xSix合金的凝固行为。应用XRD和扫描电镜分析了合金组织相组成和结构。结果表明:电弧熔炼铸锭随温度梯度出现分层;La(Fe,Si)13(简称:1∶13)相是包晶反应生成的,冷速和硅含量变化对合金的凝固行为有很大的影响,当Si含量x≤1.0时合金显微组织由α-(Fe,Si)相和共晶相La Fe Si(简称:1∶1∶1)相组成,α-(Fe,Si)(简称:α-Fe)相为主要相,随硅含量增加1∶1∶1相增多;x≥1.5时由α-Fe相、1∶13相和1∶1∶1相组成;随x增加1∶13相为主要相,1∶1∶1相减少;当x≥2.0时显微组织中1∶13相作为初生相析出,且随温度梯度和硅含量变化1∶13相的形貌不同。     

4GPa超高压凝固Mg-6Zn-3Y合金的凝固组织及相分析

利用X射线衍射仪、扫描电镜并配合能谱分析研究了Mg-6Zn-3Y合金4 GPa超高压凝固组织.结果表明:在4 GPa超高压条件下凝固时,实验合金的凝固组织得到显著细化,基体α-Mg相的晶格间距有所减小;Zn在基体α-Mg中溶解度大幅提高,Y不溶于基体α-Mg;实验合金凝固组织中出现呈对称性的四瓣或六瓣花的初晶Y固溶体,该初晶花瓣形貌完整、尺寸较大,显示其充分自由生长;先发生的共晶反应的共晶组织为成“簇”分布的共晶团,共晶相呈点状或棒状;后发生的共晶反应的组织为离异共晶.超高压凝固显著地改变了实验合金的凝固过程.     

镧、铈对铝铜合金凝固过程及凝固组织的影响

本文用热分析对比法和金相法研究了微量镧、铈对Al-5wt％Cu合金的凝固过程和凝固组织的影响规律。发现微量镧、铈能改变该合金的凝固参数,增大其过冷度和明显细化组织,微量镧、铈改变了Al-5wt％Cu合金的凝固过程,使其在α相析出之后共晶析出之前有一中间相析出。加微量铈可形成Al_8Cu_4Ce。理论分析认为,Le_2O_3、Ce_2O_3、La(OH)_3和Ce(OH),可做为α相的异质核心。     

钕对Mg7Zn2Al镁合金显微组织及力学性能的影响

采用光学显微镜、XRD、SEM和万能实验机等手段研究了稀土Nd(0.3%,0.6%,0.9%)对Mg7Zn2Al镁合金显微组织和力学性能的影响。结果表明:Mg7Zn2Al镁合金中添加Nd后,显微组织中有针状或棒状的Al2Nd和AlNd等稀土相生成,合金中的共晶组织(α-Mg+Mg32(Al,Zn)49+Mg7Zn3)得到了明显细化;但是α-Mg有粗化趋势,呈现发达的树枝状或胞状,共晶相由粗大连续的网状变为细小的块状或颗粒状分布在树枝晶的一次枝晶臂或二次枝晶臂的间隙。随着Nd含量的增加,合金的抗拉强度和延伸率呈逐渐下降趋势,显微组织的粗化是造成合金拉伸性能降低的主要原因,而硬度没有明显的变化。     

稀土对镁-铝合金抗热裂性能的影响及其机制

研究了稀土（0.1%～1.2%,质量分数）对Mg-Al合金抗热裂性能的影响及其机制.结果表明： 往Mg-Al合金中添加稀土后,合金的抗热裂性能显著下降,其原因可归为： 稀土引起了Mg-Al合金晶粒粗化,使得热裂纹萌生所需的断裂应变降低;稀土减少了Mg-Al合金中的共晶组织,缩短了枝晶通道保持开通的时间,不利于合金进行补缩;而且稀土还提高了共晶反应的温度,使得凝固后期枝晶间液膜的强度有所下降;当α-Mg枝晶连成骨架时,分布在枝晶间的Al11RE3相容易堵塞枝晶通道,增加了合金补缩的难度;Al11RE3相与α-Mg基体的凝固收缩率不同,容易产生凝固收缩应力,促进热裂纹的萌生.     

电脉冲作用下共晶铝硅合金凝固组织的变化

本文研究了连续电脉冲处理对共晶铝硅合金凝固组织的影响.结果显示,电脉冲处理后Al-12.5%Si共晶合金的凝固组织中出现了本应在过共晶成分的铝硅合金中才会出现的初生硅.X-射线能谱分析表明,电脉冲处理后α-Al枝晶中固溶Si含量降低.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。