光固化3D打印教学实验设计与研究

光固化3D打印技术作为目前较为成熟的一类增材制造技术，在打印成型过程中包括三维建模、光敏树脂制备、打印参数调控、后处理等步骤，内容涉及机械、光学、高分子化学、软件工程学等相关知识。为提升本科生的实验兴趣和实验技能，进一步培养其科研和创新意识，我们面向本科生设计了基于光固化3D打印技术的创新实验。实验采用基于光引发自由基聚合的数字光处理(DLP)3D打印技术，通过对打印过程全流程的参与实践，达到让学生了解3D打印的原理、打印材料的合成和打印技术的过程等相关知识，从而达到可以自主操作完成光固化3D打印的实验教学目的。最后，通过对实验结果的分析，进一步培养学生分析问题和解决问题的能力。     

掌上分光光度计的开发及应用

基于Arduino技术,利用AS7341传感器、全彩 LED灯珠、聚光透镜、蓝牙芯片搭配3D打印技术设计出一款掌上分光光度计。介绍了掌上分光光度计的应用实例:对不同颜色的食用色素标准液进行测定,在测定范围内,吸光度与待测样品浓度具有良好的线性拟合关系;运用于菠菜中铁元素含量的测定,所得实验数据具有良好的一致性;运用于绘制待测溶液的吸光度时间曲线,取得了良好的实验效果。结果表明自制的掌上分光光度计完全可以代替传统的分光光度计,且进一步拓展了分光光度计的功能。     

3D打印复合材料的研究进展

3D打印技术作为第三次工业革命的代表性技术之一,越来越受到工业界和投资界的关注。而3D打印成本高,不仅仅是自身的机器价格高,更重要的是打印材料价格昂贵。3D打印材料是影响3D打印技术发展与应用的关键因素。综述了近年来3D打印复合材料的研究发展以及技术创新应用,重点讨论了3D打印多功能纳米复合材料、纤维增强复合材料、无机填料复合材料、金属填料复合材料和高分子合金的性能及应用。同时对3D打印复合材料的开发及应用前景进行了分析和展望。     

光固化3D打印及其在齿科行业中的应用

光固化3D打印是最早出现的3D打印技术,经过30多年的发展,先后发展出液态树脂固化或光固化（stereolithography,SLA）、数字光处理（digital light processing,DLP）、液晶显示（liquid crystal display,LCD）、连续无分层液体界面提取技术（layerless continuous liquid interface production,CLIP）、双光子3D打印（two-photon polymerization,TPP）、全息3D打印技术等多种打印技术。光固化3D打印技术具有精度高、成型速度快等特点,因此在许多领域都有良好的应用,且前景广阔。在众多领域中,齿科领域个性化特征明显,对打印材料精度要求高,是目前光固化3D打印最有应用潜力和高附加值的领域。本文综述了光固化3D打印技术的种类、原理和技术的优缺点,并简述了光固化3D打印在齿科领域的应用。     

丝素蛋白3D打印在生物医学领域中的应用

增材制造,也称为三维(3D)打印,正推动制造、工程、医学等领域的全面创新升级。3D打印技术由于能够个性化定制生物的复杂3D微结构,构建仿生的功能化活组织或人工器官,近十年来在生物医学领域中取得了长足的发展。丝素蛋白(SF)是一种来源丰富、生物可降解、力学性能优良、细胞相容性极佳的天然有机高分子,为3D打印墨水的设计提供了一种有前景的选择。然而,作为结构蛋白,单一组分的SF具有的生理功能有限,且其经过打印后的稳定性较差,限制了SF在3D打印以及生物医药领域中的进一步发展。为此,研究人员通过化学改性技术和先进3D打印技术相结合,使得改性后的SF能够更适用于3D打印,并发展成为一种具有应用价值的生物材料。本文综述了SF的结构特征、SF的化学修饰策略、打印墨水的制备策略以及3D打印SF材料在生物医学领域的最新应用进展,并展望了3D打印SF生物材料的未来发展趋势,为其在更广阔领域的应用提供一定的借鉴。     

关于光电比色计的构造和原理

比色分析是一种很重要的分析方法。利用比色法可以比较迅速地得到相当准确的结果。一般说来,这种方法的灵敏度是很高的,例如生物体液中含量甚微的成分常常是利用比色法测定。因此在某些方面,特别是在生物化学方面,比色法占有极其重要的地位。比色法的要点就是使被测物质与一定的试剂作用而产生颜色,再比较未知液与标准液所呈的颜色以确定未知液的渡度。比色时所用的仪器过去一般多采用目光比色计,但是近年来光电比色计的应用已日趋普遍;因为光电比色     

光固化3D打印聚酰亚胺研究进展

近年来,光固化3D打印技术因高精度、定制化、整体免装配以及快速制造等成形优点,用于解决聚酰亚胺(polyimide, PI)的微型精密、异形复杂及其功能结构一体化制造技术难题,受到了研究者的广泛研究和关注。基于光固化3D打印成形原理与PI的物理化学特性,发展了一系列光固化3D打印PI材料及其成形技术。本文归纳总结了光固化3D打印PI材料设计制备准则,重点介绍了立体光刻技术(SLA)、数字光处理技术(DLP)和紫外辅助直书写技术(UV-DIW)等光固化3D打印PI研究进展,最后通过光固化3D打印PI的应用和产业化现状提出研究发展对策。     

光敏树脂合成及3D打印的综合实验教学设计与实践

针对综合实验的特点,结合创新性、趣味性等特性,设计了光敏树脂合成及3D打印综合实验。实验用1,6-己二异氰酸酯(HDI)三聚体和丙烯酸羟乙酯反应,以丙烯酰吗啉(ACMO)为活性溶剂,合成可紫外光固化的预聚体树脂。通过对预聚体树脂的—NCO测定、红外光谱、核磁共振,分析了HDI三聚体和丙烯酸羟乙酯的反应程度,表征预聚体树脂的结构及评价光固化性能,并与其他光固化单体和光引发剂配合制备黏度适宜的光敏树脂。用405 nm波长的桌面级3D打印机打印出测试样条和展示样品,通过对样条性能测试,表明该光敏树脂打印的样条具有较好的力学性能。本实验开设在本科四年级的综合教学实验中,其可以使本科生学到光固化树脂的制备方法,了解化学材料与数字模型及3D打印技术的结合,体会聚合物结构与性能的关系,增强本科生对数据的分析处理能力以及拓展本科生对其他学科的知识水平。     

3D打印技术在有机合成化学中的应用

相对于传统的材料去除-切削加工技术,3D打印作为一种"自下而上"的材料累加制造方法,不仅操作简单、制造成本更低以及可实现快速生成,而且可实现复杂结构件的精确定制.因此,3D打印已成为第三次工业革命的代表性技术.近年来,化学家们将3D打印技术与有机合成相结合,在多通道异相催化剂和新型反应装置的研发设计等方面取得了积极的进展,进而使这项技术在有机合成领域中应用越来越广泛.对近年来基于3D打印技术的有机合成研究进展进行了综述,涵盖基于3D打印异相催化剂或催化剂载体、3D打印反应装置和3D打印流反应器,并对该领域的发展趋势进行了展望.     

3D打印用高分子材料及其复合材料的研究进展北大核心CSCD

3D打印技术亦称为增材制造,是基于三维数学模型数据,通过连续的物理层叠加,逐层增加材料来生成三维实体的技术。作为第三次工业革命的代表性技术之一,3D打印材料是影响3D打印技术发展与应用的关健因素。而高分子聚合物在打印材料中占据主要地位,其中高分子复合材料具有明显优势。本文综述了近年来3D打印用高分子材料及其复合材料的研究现状,包括高分子丝材、光敏树脂、高分子粉末、高分子凝胶及其它高分子材料,并对高分子材料在3D打印领域的发展进行了展望。     

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.