浇注型环氧树脂基耐高温中子屏蔽复合材料

提出“自驱动梯度升温”概念，研制了一种耐高温，且综合性能优异的环氧树脂基中子屏蔽复合材料。通过反应动力学研究，确定基体为混合多官能度缩水甘油胺环氧树脂和混合改性酚醛胺固化剂，基体中高反应活性树脂体系固化反应放热触发低反应活性树脂体系的固化反应，实现了室温浇注工艺条件下，高性能环氧树脂无外部热源输入即可固化成型，制备耐高温中子屏蔽材料的目的。在基体材料分子结构中刚/柔性基团的匹配、体系复杂相态下的传热和功能填料的筛选等几方面研究基础上，最终得到了玻璃化转变温度（Tg）>150℃、负荷热变形温度>150℃、快中子屏蔽系数（252Cf,40 mm）>2.5、热中子屏蔽率（252Cf,40 mm）>99.98%、物理机械性能优异的中子屏蔽复合材料。该材料在服役工况苛刻的核辐射二次屏蔽领域具有现实应用场景。     

防辐射材料的研究进展

综述了X射线、γ射线和中子辐射屏蔽材料的研究现状,其中在稀土高分子防辐射材料的设计与制备方面有所侧重,并且对纳米技术的应用、屏蔽材料的优化设计等进行了简单分析、介绍,指出了未来防辐射材料研究的可能的几个主要发展方向:纳米技术及稀土材料在防辐射材料方面的应用及研究;综合辐射屏蔽材料的设计与制备,使材料兼具质轻、无毒、体积小、屏蔽范围广、屏蔽性能持久等性能;屏蔽材料物理性能优化,以提升材料拉伸强度、硬度、耐腐蚀性等;屏蔽材料的优化设计方法、遗传算法、MCNP程序、梯度材料设计等的研究与应用;以上几个方向的交叉研究与应用。     

Research Progress of Radiation-proof Material

综述了X射线、γ射线和中子辐射屏蔽材料的研究现状,其中在稀土高分子防辐射材料的设计与制备方面有所侧重,并且对纳米技术的应用、屏蔽材料的优化设计等进行了简单分析、介绍,指出了未来防辐射材料研究的可能的几个主要发展方向：纳米技术及稀土材料在防辐射材料方面的应用及研究;综合辐射屏蔽材料的设计与制备,使材料兼具质轻、无毒、体积小、屏蔽范围广、屏蔽性能持久等性能;屏蔽材料物理性能优化,以提升材料拉伸强度、硬度、耐腐蚀性等;屏蔽材料的优化设计方法、遗传算法、MCNP程序、梯度材料设计等的研究与应用;以上几个方向的交叉研究与应用。     

稀土基中子和伽马复合屏蔽材料

随着航空航天、核技术等领域的发展和核能的广泛利用，对核辐射屏蔽材料的性能也提出更高的要求。核反应中产生的中子、伽马射线的穿透能力较强，危害较大，所以对于中子、伽马辐射屏蔽材料的研究成为辐射防护研究的重点。稀土元素具有较高的中子吸收截面和高原子序数，逐渐被科研人员重视并应用于中子、伽马辐射屏蔽材料的研发中。本文简述了稀土材料在辐射屏蔽材料领域的应用，介绍了稀土元素与中子和伽马射线的作用原理；根据基体材料的类别将稀土基中子和伽马辐射屏蔽材料分为稀土金属基、稀土聚合物基、稀土玻璃基三类，分别介绍了三类稀土基复合屏蔽材料的研究进展，并分析了稀土材料用于中子、伽马辐射屏蔽存在的问题与展望。     

(W+B_4C)/Al复合材料中子屏蔽性能的蒙特卡罗模拟

使用MCNP5程序模拟了能量为14.88 Me V的快中子在(W+B_4C)/Al和W/Al复合材料中的输运过程,并与铅硼聚乙烯、聚乙烯以及钨进行对比。计算了各屏蔽材料的中子衰减性能、中子透射能谱以及中子俘获过程中释放γ射线的透射能谱,为中子屏蔽材料的选择提供了理论依据。模拟结果和实际结果吻合,证实了蒙特卡罗方法的可靠性。模拟结果也可以得出,对于快中子,高原子序数材料的屏蔽效果要好于低原子序数材料,含钨45%的复合材料的屏蔽性能与商用铅硼聚乙烯的屏蔽效能相近,但是激发γ射线能量低于铅硼聚乙烯,考虑到成分可调控性、使用温度以及力学性能等因素,(W+B_4C)/Al复合材料是一种极具应用潜力的新型中子屏蔽材料。     

键合铅离子的聚酰亚胺材料的制备及辐射屏蔽性能研究

通过离子交换法合成了对氨基苯甲酸铅盐ABA(Pb);以ABA(Pb)和2,2-双[4-(4-氨基苯氧基)苯基]丙烷(BAPP)为二胺单体、2,2-双[4-(3,4-二羧基苯氧基)苯基]丙烷二酐(BPADA)为二酐单体,N-甲基-2-吡咯烷酮(NMP)为溶剂,采用共缩聚两步法,先后合成了主链含铅离子的聚酰胺酸PAA(Pb)和聚酰亚胺PI(Pb).采用傅里叶变换红外(FTIR)光谱、核磁共振(1H-NMR)光谱和元素分析对ABA(Pb)、PAA(Pb)和PI(Pb)进行了结构表征;应用X射线衍射(XRD)、热重分析(TGA)、力学测试和γ能谱法对PI(Pb)的结构、热稳定性、力学性能及辐射屏蔽性能进行了测试.结果表明,与纯PI材料和同等铅含量、物理掺杂的PI-Pb(NO3)2样品相比,制备的PI(Pb)材料对60Co(1.33 Me V)、60Co(1.17Me V)和137Cs(0.662 Me V)的γ射线具有较大的辐射屏蔽率和较小的半值层厚度,其辐射屏蔽性能要明显优于纯PI材料和同等铅含量、物理掺杂的PI-Pb(NO3)2样品.主要原因在于PI(Pb)中铅离子是通过化学键直接键合到聚酰亚胺主链中的,实现了物理掺杂方法不能达到的铅离子均匀分散,使得γ射线与铅元素发生相互作用的几率增大,从而提高了PI(Pb)对γ射线的辐射屏蔽效果.PI(Pb)材料不仅具有良好的热稳定性和较好的力学性能,而且对γ射线的辐射屏蔽性能优良,有望成为一种具有良好应用前景的轻质γ射线辐射屏蔽材料.     

稀土／高分子复合材料的研究进展

详述了稀土／高分子复合材料的特异性能。着重说明了该复合材料的射线屏蔽性能和磁性能。指出稀土／高分子复合材料在X射线屏蔽应用中可有效弥补铅的弱吸收区;具有高稀土含量的复合高分子屏蔽材料具有强的热中子吸收能力;含稀土的共聚物具有强顺磁性,提出了制备磁性和磁智能稀土／高分子复合材料的可行性。此外,概述了稀土／高分子复合材料的3种主要制备方法：聚合法,简单掺混法和反应加工法。分析了稀土／高分子配位前体结构和配位数目对光性能的影响;指出了稀土／高分子复合材料可能具有的离聚物结构及其特征;提出原位生成稀土／高分子纳米复合结构的可行性,还对稀土／高分子复合材料的结构与性能的关系进行了详细的探讨,并对制备稀土／高分子复合材料所存在的问题进行了一定的说明。     

聚丙烯酸铅/环氧树脂辐射防护材料的制备及性能研究

采用γ辐射接枝聚合法制备了纳米聚丙烯酸铅/环氧树脂辐射防护材料,利用傅立叶变换红外光谱仪(FTIR)、X射线衍射谱仪(XRD)、透射电镜(TEM)和扫描电镜(SEM)对其结构进行了分析,利用材料万能试验机测量了拉伸性能和三点弯曲性能,利用多道γ谱仪测量了屏蔽性能.结果表明,复合材料为两相聚合物共混体系,其分散形态呈明显的海-岛结构.聚丙烯酸铅微球粒径约为5nm,具有一定的结晶,微球表面连接环氧树脂分子形成三维网状结构.复合材料特殊结构使其韧性和强度较纯环氧树脂有明显的提高,其断口呈现一定的韧性断裂的特征,对γ射线的质量吸收系数高于铅的质量吸收系数,是一种屏蔽性能十分突出的轻质材料.     

新型高分子季鏻盐改性抗菌塑料的制备及性能研究

高分子季鏻盐抗菌剂具有安全、高效的特点,使用过程中不会通过皮肤组织进行渗透。本文将实验室自制的新型高分子季鏻盐抗菌剂粉末与低密度聚乙烯(LDPE)基体材料共混,通过熔融挤出法制备了含梯度浓度抗菌剂的抗菌塑料,研究了不同抗菌剂添加浓度对基体材料熔融性质及其抗菌性能的影响,并探讨了抗菌塑料的生物安全性。结果表明,梯度浓度的抗菌剂改性塑料对金黄色葡萄球菌和大肠杆菌均有良好的抗菌效果;生物安全性测试结果表明,抗菌塑料的细胞毒性为0级,说明抗菌塑料具有较高的生物安全性。     

用新型的半固相方法合成掺钴尖晶石材料LiCo_xMn_(2-x)O_4及其性能研究

用一种新型的半固相法合成得到LiCo_xMn_(2-x)O_4材料,通过X射线衍射技术 和充放电实验对材料的结构及循环性能进行了研究。与传统的固相合成法相比,这 种半固相法显示了产物颗粒尺寸均匀,电化学性能良好的特点。通过对结构,组成 与电化学性能关系的探讨,对不同半固相法合成路线的选择及适当的优化,可得到 电化学性能良好的掺钴尖晶石材料,其中LiCo_(0.016)Mn_(1.984)O_4在室温下的 初始容量为118 mA·h/g,循环25周后,容量仍能保持在113 mA·h/g左右。通过这 种新型合成方法得到的掺钴尖晶石材料,在高温下也表现出了令人满意的充入电循 环性能。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.