20Cr2Ni4A钢经稀土渗碳和传统工艺渗碳后表层组织的观察与分析

采用ＴＥＭ微观组织观察，发现２０Ｃｒ２Ｎｉ４Ａ钢经稀土渗碳直接淬火后，渗碳层的过共析区组织是在板条马氏体为主的基体上弥散分布着细小颗粒状碳化物；而传统工艺渗碳处理后则是基体为孪晶马氏体和更细小的残留碳化物。两种工艺所形成的不同类型的基体与碳化物形成过程有关。     

ErCl3—CaCl2—LiCll三元体系相图的研究

利用ＤＴＡ研究了ＥｒＣｌ３－ＣａＣｌ２－ＬｉＣｌ三元体系相图。发现该相图有对应于ＥｒＣｌ３、ＣａＣｌ２，ＬｉＣｌ和Ｌｉ３ＥｒＣｌ６的４个液相面，５条二次结晶线，一个三元低共熔点Ｅ，一个三元转熔点Ｐ。     

石墨炉原子吸收光谱法中氯化铒和硝酸铒的背景吸收特性研究

研究了石墨炉原子吸收光谱法中ＥｒＣｌ３、Ｅｒ（ＮＯ３）３基体的背景吸收影响。背景吸收波长特性的研究说明，ＥｒＣｌ３与Ｅｒ（ＮＯ３）３的背景吸收都具有明显的波长特性。将铒基体转化为Ｅｒ（ＮＯ３）３有利于降低背景吸收值。ＥｒＣｌ３背景吸收的时间特性和原子化温度与原子化方式有关。铒基体的背景吸收峰高与灰化温度有关。     

碱金属和稀土溴化物Meyer反应的相化学研究（Ⅱ）

对ＣｓＢｒ－ＮｄＢｒ３－１３％ＨＢｒ－Ｈ２Ｏ四元体系２５℃时的相平衡进行了研究，比较了ＣｓＢｒ与ＲＥＢｒ３（ＲＥ＝Ｌ，Ｐｒ，Ｎｄ，Ｓｍ）在氢溴酸介质中反应的相化学关系发现，轻稀土的相似性和以Ｎｄ为界的“二分组效应”首次在相化学行为上有所体现，对化合物５ＣｓＢｒ．２ＲＥＢｒ３．２２Ｈ２Ｏ做了热分析测试，根据体系的相化学关系设计了新的固相反应，并进行了新类型化合物的合成。     

表面涂覆CeO_2对Co－40Cr合金氧化行为的影响

研究了表面涂覆ＣｅＯ２对Ｃｏ４０Ｃｒ合金在１０００℃、空气中恒温氧化和循环氧化的影响。并用扫描电镜／能谱（ＳＥＭ／ＥＤＸＳ）、电子探针（ＥＰＭＡ）、高分辨电子显微镜（ＨＲＥＭ）等测试手段对氧化膜的形貌和成分进行了观察分析。此外，还用声发射（ＡＥ）方法对氧化膜在热应力作用下发生的开裂和剥落进行了监测。结果表明，涂覆ＣｅＯ２后极大地提高了合金的抗恒温氧化和抗循环氧化性能。研究表明，涂覆的ＣｅＯ２主要以细小颗粒的形式高度弥散存在于氧化膜的外表面，并且主要分布于氧化物晶界上，其中部分ＣｅＯ２以更加细小（１０～２０ｎｍ）的形式存在于Ｃｒ２Ｏ３晶粒内部。这些弥散分布的ＣｅＯ２颗粒改变了Ｃｒ２Ｏ３氧化膜的生长机制，通过阻碍Ｃｒ３＋阳离子向外扩散，降低了氧化膜的生长速率，细化了氧化膜的晶粒并提高了膜的高温塑性，使氧化膜在基体上有较好的粘附性     

稀土溴化物与甘氨酸配合物标准摩尔生成焓的测定

采用量热法在２９８１５±０１０Ｋ测量了ＲＥＢｒ３·３Ｇｌｙ·３Ｈ２Ｏ（ＲＥ＝Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｙ；Ｇｌｙ为甘氨酸）和甘氨酸在水中的积分溶解热，及ＲＥＢｒ３·ｎＨ２Ｏ（ＲＥ＝Ｌａ、Ｃｅ、Ｐｒ时，ｎ＝７；ＲＥ＝Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｙ时，ｎ＝６）在甘氨酸水溶液中的积分溶解热。用本研究设计的热化学循环求得上述１０种ＲＥＢｒ３·３Ｇｌｙ·３Ｈ２Ｏ配合物的标准摩尔生成焓，并计算出它们的晶格能。     

同位素稀释火花源质谱法直接测定高纯氧化钆中的稀土杂质元素

本文采用同位素稀释火花源质谱法直接测定高纯氧化钆中Ｎｄ、Ｓｍ、Ｅｕ、Ｄｙ、Ｅｒ５个元素，再以该法测定的Ｎｄ和Ｅｒ为内标，同时测定Ｌａ、Ｃｅ、Ｐｒ、Ｙ和Ｔｂ、Ｔｍ、Ｌｕ８个元素，方法的测定下限ΣＲＥ为８μｇ／ｇ，回收率为８５％～１１４％，相对标准偏差为４％～２１５。     

双钙钛矿氧化物REEuCr2O6的^151Eu Mossbauer谱研究

利用高温固相反应合成了双钙钛矿氧化物ＲＥＥｕＣｒ２Ｏ６（ＲＥ＝Ｌａ，Ｐｒ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ）。对样品进行了ＸＲＤ、ＩＲ及＾１５１Ｅｕ的Ｍｏｓｓｂａｕｅｒ谱测试，结果表明所有化合物为正交结构；随着ＲＥ原子序数的增加，晶胞体积减小，同质异能移位与样品的晶胞体积呈线性关系；四极裂矩为负值，且随ＲＥ原子序数的增加其绝对值增大。     

氨基酸及其希土配合物的热化学性质研究

用转动弹热量计测定了ＣＬ－α－氨基正丁酸的燃烧能，换算它的标准生成焓。并且计算了组成为ＢＥＣｌ３．Ｂ２．５Ｈ２Ｏ（ＲＥ＝Ｅｕ，Ｇｄ，Ｄｙ，Ｅｒ，Ｙｂ，Ｙ；Ｂ＝α－氨基正丁酸）的固态配合物的标准生成焓。     

三氯化一缬氨酸六水合稀土固体配合物的合成及红外光谱

在水溶液中合成了Ｌｎ（Ｖａｌ）·Ｃｌ＿３·６Ｈ＿２Ｏ（Ｌｎ＝Ｌａ，Ｎｄ，Ｓｍ，Ｇｄ，Ｅｒ）．利用元素分析和容量滴定法确定了其组成。测定了配合物的红外光谱，对其主要红外吸收带进行了归属。红外光谱结果表明，缬氨酸以内盐的形式存在于配合物中，并通过羟基与稀土离子配位，６个水分子亦参与了配泣，推测Ｌａ和Ｎｄ配合物具有一维无限长锭结构，而Ｓｍ、Ｇｄ和Ｅｒ配合物为双核配合物．     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.