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     

高效液相色谱法测定3D打印用塑料线材热熔时挥发的醛酮类化合物

自制了一种气体采集装置收集熔融沉积成形3 D打印用聚苯乙烯(ABS)、聚乳酸(PLA)、聚己内酯(PCL)等塑料线材热熔时挥发出的气体,并采用高效液相色谱法(HPLC)测定其中15种有害醛酮类气体(甲醛、乙醛、丙酮、丙醛、丁烯醛、甲基丙烯醛、丁酮、丁醛、苯甲醛、环己酮、戊醛、对甲基苯甲醛、邻/间甲基苯甲醛和己醛)含量....     

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.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.