镧对Cu_6Sn_5长大驱动力及焊点可靠性的影响

在Sn60 Pb40钎料合金中加入微量稀土元素镧可以抑制表面组装焊点界面处Cu6 Sn5金属间化合物的生长 ,进而使焊点热疲劳寿命提高两倍。基于扩散动力学的热力学计算结果表明 ,添加微量稀土元素镧可降低Cu6 Sn5金属间化合物的长大驱动力 ,但存在一个镧的有效局部摩尔分数范围 ,0 18%是其极限值 ,0 0 8%是其最佳值。     

镧对Cu6Sn5长大驱动力及焊点可靠性的影响

在Sn60-Pb40钎料合金中加入微量稀土元素镧可以抑制表面组装焊点界面处Cu6Sn5金属间化合物的生长,进而使焊点热疲劳寿命提高两倍。基于扩散动力学的热力学计算结果表明,添加微量稀土元素镧可降低Cu6Sn5金属间化合物的长大驱动力,但存在一个镧的有效局部摩尔分数范围,0．18％是其极限值,0．08％是其最佳值。     

镧对钛基钎料钎焊Ti3Al和GH536的影响

研究了La的添加对Ti-Cu-Ni基钎料的性能,以及对Ti3Al和GH536钎焊接头的显微组织和机械性能的影响.研究结果表明： 采用添加La的钎料,可显著提高钎焊接头的拉伸强度,其原因在于La能明显提高钎料与母材的润湿性能,促进母材和钎料中元素的扩散.     

稀土元素在LD30铝合金真空钎焊中的作用

研究了添加La和Ce的Al-Si基钎料真空钎焊LD30铝合金接头的力学性能，微观组织形貌和EDS，并与未添加稀土元素的Al-Si基钎料真空钎焊接头进行对比。结果表明，添加稀土元素的LD30铝合金真空钎焊接头抗拉强度为288MPa，达母材抗拉强度的97．6％，明显高于未添加稀土的LD30合金真空钎焊接头。其机制在于La,Ce能够明显提高Al-Si基钎料与LD30铝合金的润湿性能，改善LD30铝合金真空钎焊接头焊缝及其基体中杂质元素的分布，促进钎料和母材中各元素的均匀扩散，从而提高真空钎焊接头的力学性能。     

含稀土Sn-Zn-Bi系无铅钎料润湿性能的研究

通过向Sn-Zn-Bi系钎料合金中添加适量合金元素Ga,Cu和La,制备了对Cu母材具有较好润湿性能的Sn-8.9Zn-2.7Bi-1.0Ga-0.5Cu-0.2La无铅钎料,其润湿角为25.1°。同时,还研究了无铅钎料中稀土元素La以及合金元素Ga的微量变化对钎料的润湿性及与母材金属结合界面组织结构的影响。研究发现,La和合金元素Ga的含量对Sn-Zn-Bi系无铅钎料润湿性能有较大影响,适量添加无论是在空气中还是在氮气保护下,均可以改善钎料的润湿性。     

铈对CuPNiSn非晶焊料性能的影响

报道了单辊法制备的三个系列11种CuPNISn非晶合金的晶化温度、熔化温度区间、流布面积、Cu-Cu对接接头的抗拉强度及钎缝显微组织的分析结果。发现铈的加入可明显提高钎焊接头强度,并细化晶粒。同时还发现随焊料中(Ni+Sn)含量的降低,接头从脆性断裂变为韧性断裂,其抗拉强度大大高于母材的屈服强度。     

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。     

微量稀土对超导稳定化基体铜材的性能和组织的影响

研究了微量稀土元素对铜的机械性能、导电性和组织的影响，在铜中加入微量钇、钕、镝、铒和富铈混合稀土后，使铜的抗拉强度有所提高，并保持良好的塑性和导电性。     

微量铈对Sn-0.7Cu-0.5Ni焊料合金组织与性能的影响

研究了微量铈对Sn-0.7Cu-0.5Ni焊料合金性能（物理性能、润湿性能及力学性能等）与组织的影响.结果表明,与Sn-0.7Cu-0.5Ni焊料合金相比,添加铈的作用较明显,适量的铈可有效细化组织,抑制焊料/Cu界面的金属间化合物的生长; 对焊料熔化温度影响不大; 略降低焊料合金的电阻率; 未能改善焊料合金的耐蚀性能; 当铈含量为0.1%时,焊料有较好的润湿性.当铈含量为0.05%～0.10%时焊料合金具有较好的综合性能.     

铈对ZZn4-1锌合金性能和微观组织的影响

在ＺＺｎ４ － １ 锌合金中添加微量铈, 能使其金属模铸造条件下的抗拉强度及布氏硬度有较大提高, 并能有效地改善其微观组织、细化晶粒。在压铸条件下, 添加铈后, 能使压铸件微观组织中无论是初生的η相或共晶相均比没有添加铈的合金细小、弥散、均匀, 从而使其力学性能及工艺性能得到提高, 成品合格率大幅度增加。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

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.     

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.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

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。