多晶硅表面金属催化化学腐蚀法制绒研究现状

在多晶硅太阳能电池的生产过程中,金刚线切割(Diamond wire sawing, DWS)技术具有切割速度快、精度高、原材料损耗少等优点,受到了广泛关注。金刚线切割多晶硅表面形成的损伤层较浅,与传统的酸腐蚀制绒技术无法匹配,金属催化化学腐蚀法应运而生。金属催化化学腐蚀法制绒具有操作简单、结构可控且易形成高深宽比的绒面等优点,具有广阔的应用前景。本文总结了不同类型的金属催化剂在制绒过程中的腐蚀机理及其形成的绒面结构,深入分析和讨论了具有代表性的银、铜的单一及复合催化腐蚀过程及绒面结构和电池片性能。最后对金刚线切割多晶硅片表面的金属催化化学腐蚀法存在的问题进行了分析,并展望了未来的研究方向。     

Recent Advances in Late-Stage Construction of Stapled Peptides via C−H Activation

Stapled peptides have been widely applied in many fields, including pharmaceutical chemistry, diagnostic reagents, and materials science. However, most traditional stapled peptide preparation methods rely on prefunctionalizations, which limit the diversity of stapled peptides. Recently, the emergence of late-stage transition metal-catalyzed C−H activation in amino acids and peptides has attracted wide interest due to its robustness and applicability for peptide stapling. In this review, we summarize the methods for late-stage construction of stapled peptides via transition metal-catalyzed C−H activation.     

抗坏血酸对大豆蛋白乳液抗氧化稳定性的研究

本试验通过研究抗坏血酸对大豆蛋白乳液体系中油脂的抗氧化作用,明确抗坏血酸作为天然抗氧化剂在乳化体系中的抗氧化机理。本研究采用溶解氧(DO)和顶空氧气消耗法测定大豆蛋白乳液体系在pH 3.0的环境下抗坏血酸对乳液体系氧消耗的影响;验证不同过渡金属Fe~(2+)、Cu~+对抗坏血酸在乳液中清除自由基能力、降解速率、乳液粒径变化和对大豆蛋白乳液氧化稳定性影响。研究表明:通过激光粒度仪分析乳液在储存期间的粒径变化趋势相同,含有抗坏血酸的乳液与对照组没有明显区别,加入金属离子的乳液粒径偏大;15 mmol/L抗坏血酸能够几乎完全消耗乳液体系中溶氧量;抗坏血酸能够在过渡金属Fe~(2+)和Cu~+发生促氧化时通过转移电子和清除体系中的自由基起到抗氧化作用;与对照组相比,Fe~(2+)和Cu~+可加速抗坏血酸降解和氧的消耗,但并没有引起乳液氢过氧化物和己醛含量的快速增加。说明抗坏血酸在大豆蛋白乳液体系中可通过清除自由基和加速乳液体系中氧消耗的多种机制稳定乳液。     

过渡金属催化下有机高价碘盐参与的反应研究(一)

根据不同反应类型对过渡金属催化下有机高价碘盐在有机合成中的应用研究进行总结。     

金属催化重氮化合物参与的分子间多组分反应研究进展

本文根据反应历程综述了金属催化重氮化合物参与的分子间MCR的研究进展,经羰基叶立德和亚胺叶立德中间体的1,3-偶极环加成反应是构建四氢呋喃环、1,3-二氧五环、四氢吡咯环等含氧、氮的五元杂环结构的有效方法,具有反应产率高、立体选择性好等特点;经1,2-偶极结构的铵基叶立德和氧鎓叶立德中间体的亲核加成反应能够一步合成重要的有机中间体.     

全角度陷光的微-纳复合绒面单晶PERC太阳电池

采用银金属催化化学腐蚀（Ag-MCCE）技术在碱腐蚀的金字塔微米初级绒面结构上制备均匀的纳米次级绒面结构,并研究银纳米颗粒在微米金字塔表面的附着特性及其对纳米结构均匀性和电池性能的影响。结果表明,通过添加聚乙烯吡咯烷酮（PVP）可改善银纳米颗粒在微米金字塔表面的附着均匀性,制备的纳米结构在微米金字塔结构表面分布均匀,且便于后道SiN_x的钝化;制得的单晶PERC电池平均效率达到22.22%,较未改善的对比组提升0.46%;独特的微-纳复合绒面（NOM-texture）可实现单晶太阳电池的全角度陷光,兼顾新型光伏屋顶等光伏建筑一体化（BIPV）场合对电池高转换效率和准全向外观的双重要求。     

采用热蒸发和氧化技术制备金属诱导的In2O3纳米塔

利用热蒸发、氧化及金属诱导技术,具有不同截面的大尺度In2O3纳米塔被成功地合成,这些纳米塔的形貌、结构特征与诱导金属的种类（金、银或锡）、衬底和蒸发源的相对位置、生长温度以及气流速率等有较大关系。采用锡作为金属诱导,In2O3纳米塔不能被合成,这说明金属液滴在这些纳米塔的生长初期起到了非常重要的作用。In2O3纳米塔的形成归因于一个竞争性的横向和轴向生长模式,横向生长由气相-固相机理控制,而轴向生长由金属液滴辅助的气体-液体-固体生长机理控制。具有奇异的塔状结构的In2O3纳米塔在光电器件和气体传感器等方面有潜在的应用前景。     

Methane formation by metal-catalyzed hydrogenation of solid calcium carbonate

A study of the hydrogenation of solid CaCO₃ has shown that the addition of Pd and Ir catalysts causes a change in the gaseous product and, consequently, in the kinetics of the reaction. In the absence of catalyst, CO is formed at higher than 700 K with the activation energy of 236 kJ/mol and a nearly half order with respect to H₂ pressure, which is explained by the mechanism consisting of predecomposition and reduction. In the presence of the catalysts, CH₄ is exclusively formed even at 573 K at which the equilibrium decomposition pressure of CaCO₃ is extremely low, 1.1 × 10⁻⁵ Torr. Activation energies found in the range 105–118 kJ/mol and the H₂-pressure dependence of the initial rate suggest the direct interaction of CaCO₃ with spilt-over hydrogen atoms. This revised version was published online in November 2006 with corrections to the Cover Date.     

Protein carbonyls in meat systems: a review

Protein oxidation (P-OX) is an innovative topic of increasing interest among meat researchers. Carbonylation is generally recognized as one of the most remarkable chemical modifications in oxidized proteins. In fact, the quantification of protein carbonyls by the dinitrophenylhydrazine (DNPH) method is the most common procedure for assessing P-OX in meat systems. Numerous studies have investigated the occurrence of protein carbonylation right after slaughter and during subsequent processing and cold storage of meat. However, the significance of protein carbonylation in meat systems is still poorly understood. Beyond their role as markers of protein oxidation, specific protein carbonyls such as α-aminoadipic and γ-glutamic semialdehydes (AAS and GGS, respectively) are active compounds that may be implicated in several chemical reactions with relevant consequences on meat quality. The formation of protein carbonyls from particular amino acid side chains contribute to impair the conformation of myofibrillar proteins leading to denaturation and loss of functionality. Recent studies also highlight the potential impact of specific protein carbonyls in particular meat quality traits such as water-holding capacity (WHC), texture, flavor and its nutritional value. As a truly emerging topic, the results from current studies provide grounds from the development of further investigations. The present paper reviews the current knowledge on the mechanisms and consequences of protein carbonylation in meat systems and aims to encourage meat researchers to accomplish further investigations on this fascinating research topic.