Biobased poly(2,5‐furandimethylene succinate‐co‐butylene succinate) crosslinked by reversible Diels–Alder reaction

We synthesized biobased poly(2,5‐furandimethylene succinate‐co‐butylene succinate) [P(FS‐co‐BS)] copolymers by polycondensation of 2,5‐bis(hydroxymethyl)furan, 1,4‐butanediol, and succinic acid. These copolymers could be crosslinked to form network polymers by means of a reversible Diels–Alder reaction with bis‐maleimide. The thermal properties, mechanical properties, and healing abilities of the P(FS‐co‐BS)s and the network polymers were investigated. The mechanical properties of the network polymers depended on the comonomer composition of the P(FS‐co‐BS)s and the maleimide/furan ratio in the network polymers. Some of the copolymers exhibited healing ability at room temperature, and their healing efficiency was enhanced by solvent or heat. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 216–222     

A facile method to synthesize high‐molecular‐weight biobased polyesters from 2,5‐furandicarboxylic acid and long‐chain diols

In this study, biobased furan dicarboxylate polyesters have been prepared using 2,5‐furandicarboxylic acid (FDCA) and diols with high number of methylene groups (long‐chain diols), namely, 8, 9, 10, and 12. Because of the high boiling points of these diols, a modified procedure of the well‐known melt polycondensation was applied in this work. According to this, the dimethyl ester of FDCA (DMFD) reacted in the first transesterification stage with the corresponding diols forming bis‐hydroxy‐alkylene furan dicarboxylates (BHFD). In the second stage, the BHFD reacted with DMFD again at temperatures of 150–170 °C (for 4–5 h), and in the final stage, the temperature was raised to 210–230 °C (vacuum was applied for 2–3 h). The molecular weight of the polyesters and the content of oligomers, as was verified by gel permeation chromatography analysis, depend on the polycondensation time and temperature. The chemical structure of the polyesters was verified from ¹H NMR spectroscopy. All the polymers were found to be semicrystalline, with melting temperatures from 69 to 140 °C depending on the diol used. In addition, the mechanical properties also varied with the type of diol. The higher values were observed for poly(octylene 2,5‐furanoate), whereas the lowest values were observed for poly(dodecylene 2,5‐furanoate) with the higher number of methylene groups in its repeating unit. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2617–2632     

高职院校混合式教学改革的实践及思考--以浙江省级精品在线开放课程《国际金融实务》为例

随着"互联网+"教育对教学的广泛影响,开发建设数字化教学资源、实施线上线下相结合的混合式教学已成为高职院校课程建设、教学改革的发展方向。浙江省级精品在线开放课程《国际金融实务》混合式教学改革的实践表明,混合式教学模式能够实现激发学生学习兴趣、拓展课堂教学时间和空间、提升课堂教学互动、促进学生个性化自主学习、带动欠发达地区高职院校教学水平提升等效果。着眼未来发展,混合式教学改革还需从完善线上线下整体教学设计、完善教师建设应用在线课程的激励机制、完善在线课程建设应用的考核机制、教育行政主管部门加强顶层设计避免多平台重复建设等方面进一步推进,优化混合式教学改革的应用效果。     

Neural network modeling of hydrological systems: A review of implementation techniques

This paper presents a review of procedural steps and implementation techniques used in the development of artificial intelligence models, generally referred to as artificial neural networks (ANNs), within the water resources domain. It focusses on identifying different areas wherein ANNs have found application thereby elucidating its advantages and disadvantages as well as various challenges encountered in its use. Results from this review provide useful insights into how the performance of ANNs can be improved and potential areas of application that are yet to be explored in hydrological modeling. Recommendations for Resource Managers

• Development of integrated and hybrid artificial intelligent tools is critical to achieving improved forecasts in hydrological modeling studies.

• Further research into comprehending the internal mechanisms of neural networks is required to obtain a practical meaning of each network component deployed to solve real‐world problems.

• More robust optimization techniques and tools like differential evolution, particle swarm optimization and deep neural nets, are yet to be fully explored in the water resources analysis, and should be given more attention to enhance neural networks aptitude for modeling complex and nonlinear hydrological processes.

     

引文分析在图书馆馆藏资源建设中的作用--以常州大学化学工艺硕士论文引文为例

对常州大学化学工艺专业2011—2013年硕士学位论文引文的数量、语种、类型、年代及该专业的文献半衰期进行了统计分析，为图书馆馆藏期刊资源建设提供了参考依据。     

黄石地区野生藤本植物资源及其利用

黄石地区野生藤本植物有84种(含4变种),隶属于55属27科。概述了黄石野生藤本植物资源的分类和主要形态特征,并为其综合利用提出了初步建议。     

Partially bio‐based tri‐ and hexaallyl monomers: Synthesis from naturally occurring myo‐inositol and polyaddition with dithiols

myo‐Inositol, a naturally occurring cyclic hexaol, was converted to 2,4,6‐tri‐O‐allyl‐myo‐inositol and 1,2,3,4,5,6‐hexa‐O‐allyl‐myo‐inositol. Polyaddition of the former product, a tri(allyl ether) bearing three hydroxyl groups, with dithiols yielded the corresponding networked polymers. Their glass transition temperatures (T_gs) were higher than those of networked polymers formed by the polyaddition of 1,3,5‐tri‐O‐methyl‐2,4,6‐tri‐O‐allyl‐myo‐inositol. This implied the reinforcement of the networks by hydrogen bonding between the hydroxyl groups. Polyaddition of the latter product, a hexa(allyl ether), with dithiols yielded the corresponding networked polymers with much higher T_gs than those of all of the aforementioned networked polymers. This implied that efficient use of the hexafunctional monomer leads to the formation of more densely crosslinked polymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1524–1529     

关于高职图书馆资源建设的研究

随着数字化、网络化的日益普及，提升高职院校图书馆的服务水平成为当务之急。深入分析了高职图书馆的现状特别是其资源建设的情况，提出了高职院校图书馆资源建设的对策。     

Cross‐metathesis of biorenewable dioxalates and diols to film‐forming degradable polyoxalates

Starting from commonly available sugar derivatives, a single step protocol to access a small family of isohexide‐dioxalates ( 2a–c ) has been established. The synthetic competence of 2a–c has been demonstrated by subjecting them to condensation polymerization. Quite surprisingly, the proton NMR of poly(isomannide‐co‐hexane)oxalate revealed a 1:2 ratio between isomannide‐dioxalate ( 2a ) and 1,6‐hexanediol ( 3a ) in the polymer backbone. This intriguing reactivity was found to be an outcome of a cross metathesis reaction between 2a and 3a . The cross metathesis products 3a ”[2‐(2‐methoxyacetoxy)ethyl 2‐(2‐hydroxyethoxy)‐2‐(λ3‐oxydanylidene)acetate] and 2a ‘(3R,6R)‐6‐hydroxyhexahydrofuro[3,2‐b]‐furan‐3‐yl methyl oxalate were isolated in a control experiment. Based on direct and indirect evidence, and control experiments, an alternative polymerization mechanism is proposed. Polymerization conditions were optimized to obtain polyoxalates P1(2a‐3a)‐P9(2c‐3c) with molecular weights in the range of 14,000–68,000 g/mol, and narrow polydispersities. The identity of the polyoxalates was unambiguously established using 1‐2D NMR spectroscopy, MALDI‐ToF‐MS, and GPC measurements. The practical implication of these polymers is demonstrated by preparing transparent, mechanically robust films. The environmental footprint of the selected polyoxalates was investigated by subjecting them to solution and solid‐state degradation. The polyoxalates were found to be amenable to degradation. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1584–1592     

基于办学特色的公安院校文献资源建设研究——以南京森林警察学院为例

阐述了南京森林警察学院的办学特色和文献资源建设现状,探讨了公安院校文献资源建设目前面临的问题,提出了基于特色办学的公安院校文献资源建设途径与措施。