关于《分析测试学报》精选论文推送活动的公告北大核心CSCD

《分析测试学报》已从2018年第5期起,开展"精选论文推送"活动,每期精选4篇论文,并经二次编辑、加工精炼后通过微信公众号的形式以每周一次的频率推送给广大读者。"《分析测试学报》精选论文推送"旨在与大家分享分析测试和分析化学领域的前沿研究成果和发现,启发科研工作思路,     

关于《分析测试学报》精选论文推送活动的公告

正《分析测试学报》已从2018年第5期起,开展"精选论文推送"活动,每期精选4篇论文,并经二次编辑、加工精炼后通过微信公众号的形式以每周一次的频率推送给广大读者。"《分析测试学报》精选论文推送"旨在与大家分享分析测试和分析化学领域的前沿研究成果和发现,启发科研工作思路,     

“未来教室”环境下高中化学实验教学的尝试与反思

"StarC云端一体化教学平台"软件系统支撑下的"未来教室"逐渐被应用于高中化学实验教学。尝试将"StarC云端一体化教学平台"中的"云端""多屏互动技术""课件制作工具"等技术应用于高中化学实验教学,并取得了较好的教学效果。     

“四问”驱动化学问题解决的途径及案例

1"四问"驱动完成问题解决四问"启问、探问、追问、回问"构成一个问题解决循环。通过启问,依据目标,提出问题;探问,拾级而上,解决问题;追问,质疑交流,促进思维;回问,反思提炼,总结提升。一个问题解决循环可以包含上述全部4问,也可以只包含其中的3问或2问;反之,一个问题解决循环也可以重复使用其中某些类型的问题。一节课可以设置1个或多个问题解决循环。     

一种自动送样装置

<正>公开号:CN103852586A公开日:2014.06.11申请人:湖南三德科技股份有限公司摘要本发明公开了一种自动送样装置,包括样盘平台平移机构、坩埚推送机构和纵向平移机构,样盘平台平移机构包括样盘平台和样盘平台平移驱动组件,在样盘平台平移驱动组件的驱动下,样盘平台上的坩埚按照顺序传送至坩埚推送机构的推送位;坩埚推送机构上的坩埚推送方向与样盘平台     

催化作用中的活性集团理论

1939年莫斯科大学教授尼古拉·伊万诺维奇·柯巴捷夫提出了一个催化的基本理论,叫做活性集团理论。这个理论的基本原理可以说明如下: (1)催化剂的非晶相(原子相)是催化活性的承担者,而与其相应的结晶相(金属催化剂或载体)只起一个无催化作用的载体作用(подкладка)。 (2)任何真实表面都具有镶嵌结构,这个结晶相载体也是一样,是由许多密闭的“蜂窝”(小区域)组成的(图1)——这些小区域叫做“活动区”。彼此之间有能栅或几个屏壁相互隔开,在一定的程度下,在各区域内表面上的原子都不能超越通过这种能栅或几个屏壁。     

增感屏对X线胶片屏片组合性能的影响

增感屏是X线摄影中的重要器材,实际拍片时是在X线胶片的两面夹以增感屏,以提高X线的曝光效率,因此其性能将直接影响X线胶片的屏片组合性能,从而直接影响图像的质量。最近ISO制定了一个测定医用X线胶片性能的新方法—ISO 9236-1。这个新的国际标准也是把胶片和增感屏的组合作为一个整体进行测定。ISO 9236的制定是医用X线胶片性能标定技术上的重大突破,其测试过程更接近于实际拍摄条件,当然会对胶片的生产、应用产生深远的影响。     

完善地沟油检测方法健全食品安全检测体系——“色谱技术在地沟油检测中的应用”专栏引言

<正>近年来,食品卫生与安全成为备受关注的热门话题,继"苏丹红"、"三鹿奶粉"和"瘦肉精"等事件之后,"地沟油"掺杂使假问题又一次牵动了广大民众的心,使人们谈"地沟油"而色变。"地沟油"或非正常食用植物油,一般指从下水道中的油腻漂浮物或泔水提炼出的油、劣质动物器官组织加工提炼的油和煎炸老油,以及含有这些油的勾兑油。由于这类     

镧系元素的失屏参数及应用

陈念贻和温元凯根据原子光谱数据改进了Slater原子轨函的计算。他们从中定义了一个无量纲数失屏参数R_ξ,给出了43种元素的失屏参数和某些应用。但是对镧系元素仅给出La(Ⅲ)的失屏参数值。本文介绍一个计算镧系元素失屏参数的方法,并用这些参数讨论镧系元素性质递变规律。按陈-温改进Slater原子轨函的方法,失屏     

关于论文署名问题

在科学论文上署名是一个很严肃的问题,一个科学道德和做人道德的问题,一个要对研究结果、结论及其后果负责的问题(即"文责自负"),不是一个随随便便的问题,更不是可以用来作某种"交换"的商品或礼品.时下,在我国学术腐败日益猖獗的形势下,这个问题被弄得很乱.     

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.