教学“新基建”背景下物理化学课程改革探索

物理化学是化学化工类专业必修的基础理论课程之一,其教学内容理论性强,概念抽象。传统的授课仅是围绕物理化学教材内容,没有将物理化学课程的基础理论性、实践应用性、高阶挑战性及思政育人形成完整授课体系,难以适应新时代发展需求。在教学“新基建”背景下,该文针对物理化学课程授课中存在的问题,从课程内容、课程实验、教学方法和思政协同育人等方面入手,探讨课程“新基建”的建设方案,提出“基础性、实践性、高阶性、思政育人”的“四位一体”的物理化学课程建设方案,对物理化学及其他课程的改革提供一定的借鉴作用。

季铵化纳米纤维素增强预油漆纸性能

【目的】为解决预油漆纸用三聚氰胺–脲醛树脂存在甲醛释放等环保问题,开展了利用无醛水性浸渍胶黏剂和涂料制备无醛预油漆纸的应用技术研究。【方法】以季铵化纳米纤维素改性水性丙烯酸酯乳液作为浸渍胶黏剂制备预浸胶纸,并在表层辊涂水性丙烯酸酯类涂料制备预油漆纸。利用X射线光电子能谱仪(XPS)、热重分析仪和万能力学试验机分别对预油漆纸的表面化学基团和元素含量变化、热稳定性能和拉伸性能进行分析和测试。【结果】原纸经浸渍季铵化纳米纤维素增强水性丙烯酸酯乳液并涂饰油漆后制备的预油漆纸纵向抗张强度和断裂伸长率分别增加了4.2倍和3.2倍,并且可任意角度折叠,柔韧性能优异。预油漆纸甲醛释放量为0.12 mg/L,达到国内外干燥器法甲醛释放量最严等级—日本标准F星级认证中F^(☆☆☆☆)级(甲醛释放量≤0.3 mg/L)要求。XPS分析表明:与原纸相比,预油漆纸表面化学结构和元素含量发生变化,经过丙烯酸酯胶黏剂和涂料处理后表面疏水性能提高。热重分析结果显示:与原纸相比,预油漆纸的热稳定性能略微下降。除表面耐磨性能和硬度,预油漆纸饰面板的抗冲击性能、耐干热性能、耐湿热性能、耐水性能和耐污染腐蚀性能均能满足GB/T 15102—2017《浸渍胶膜纸饰面纤维板和刨花板》和GB/T 37005—2018《油漆饰面人造板》的要求。【结论】利用季铵化纳米纤维素增强的预油漆纸具有良好的环保和力学性能。

儿茶酚化/季铵化双重改性高分子量壳聚糖基复合银纳米粒子

银纳米粒子比表面积大,抗菌效力强,被广泛应用于生物医学领域,但浓度过高时存在毒性。通过双重化学改性,水相中实现高分子量壳聚糖的溶解分散,并利用邻苯二酚结构的还原稳定作用制得一种儿茶酚化/季铵化双重改性壳聚糖基复合银纳米粒子(CQCS-AgNPs),有望发挥季铵化壳聚糖和银的协同抗菌效应。核磁共振氢谱法(1H NMR)和X射线衍射(XRD)表征证实CQCS的成功合成,季铵化度为10%,CQCS1的儿茶酚化度为15%,水中溶解度达21.5 mg/mL。透射电子显微镜(TEM)、动态光散射仪(DLS)、分光光度仪(UV)证实CQCS-AgNPs的成功制备,并具有良好的分散性和稳定性,粒径范围为3~25 nm。溶液共培养抗菌试验、抑菌圈试验和CCK-8体外细胞毒性试验证明银浓度仅为0.0197μg/mL时的CQCS-AgNPs对革兰氏阳性菌金黄色葡萄球菌和革兰氏阴性菌大肠杆菌具有优异的抗菌性能,同时对NIH3T3细胞的毒性较小。CQCS-AgNPs有效减少99.8%的银使用量,从而降低银的毒性,可用作广谱高效低毒抗菌剂。

磺化聚醚醚酮复合膜的制备及其性能研究

采用共混溶液浇铸法制备了磺化聚醚醚酮(SPEEK)/季铵化聚降冰片烯聚合物(TAPNM)复合质子交换膜,并对其力学性能、尺寸稳定性、离子交换容量和质子传导率进行表征。结果表明,制备的复合膜具有良好的透明性和均匀性,且致密无明显缺陷,具有良好的相容性。复合膜的尺寸稳定性测试和力学性能测试结果表明,TAPNM的引入显著增强了复合膜的尺寸稳定性和力学性能。在TAPNM质量分数为5%左右时,可以有效提升复合膜的质子传导率,30℃条件下质子传导率达到53.19 mS/cm,是SPEEK膜的1.2倍。

基于项目与竞赛驱动式模块化单片机教学的研究

在新工科背景下,结合疫情形势的严峻性,利用信息技术与教育教学的深度融合,提出一种新工科背景下结合虚拟仿真软件的基于项目与竞赛驱动式模块化教学的研究。结合传统单片机教学存在的问题,通过四大改革举措,提出将一种课堂教学转变为“理论+案例+仿真+竞赛”的四位一体的教学新形式。

Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone)for anion-exchange membrane

Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

Cytocompatibility with osteogenic cells and enhanced in vivo anti-infection potential of quaternized chitosan-loaded titania nanotubes

Infection is one of the major causes of failure of orthopedic implants. Our previous study demonstrated that nanotube modification of the implant surface, together with nanotubes loaded with quaternized chitosan （hydroxypropyltrimethyl ammonium chloride chitosan, HACC）, could effectively inhibit bacterial adherence and biofilm formation in vitro. Therefore, the aim of this study was to further investigate the in vitro cytocompatibility with osteogenic cells and the in vivo anti-infection activity of titanium implants with HACC-loaded nanotubes （NT-H）. The titanium implant （Ti）, nanotubes without polymer loading （NT）, and nanotubes loaded with chitosan （NT-C） were fabricated and served as controls. Firstly, we evaluated the cytocompatibility of these specimens with human bone marrow-derived mesenchymal stem cells in vitro. The observation of cell attachment, proliferation, spreading, and viability in vitro showed that NT-H has improved osteogenic activity compared with Ti and NT-C. A prophylaxis rat model with implantation in the femoral medullary cavity and inoculation with methiciUin-resistant Staphylococcus aureus was established and evaluated by radiographical, microbiological, and histopathological assessments. Our in vivo study demonstrated that NT-H coatings exhibited significant anti-infection capability compared with the Ti and NT-C groups. In conclusion, HACC-loaded nanotubes fabricated on a titanium substrate show good compatibility with osteogenic cells and enhanced anti-infection ability in vivo, providing a good foundation for clinical application to combat orthopedic implant-associated infections.

Electroneutral Quaternization/Sulfosuccination for Alleviating the Adverse Effect of Paste Aging on the Properties of Corn Starch Film

For the purpose of alleviating the adverse effect of paste aging on the properties of corn starch film, a series of electroneutrally quaternized/sulfosuccinylated starches（EQSS） with different degrees of substitution（DS） were synthesized via the quaternization/sulfosuccination of acid-thinned corn starch（ATS） by varying the amounts of N-（3-chloro-2-hydroxypropl） trimethylammonium chloride, maleic anhydride, and sodium hydrogen sulfite. The influence of paste aging on the properties of starch film cast from heat-induced starch paste was investigated and the properties were explored in terms of tensile strength, elongation, work at break, degree of crystallinity, and flex-fatigue resistance. The experimental results showed that the paste ageing generated adverse influence on the elongation, work at break, and flex-fatigue resistance of starch film. Further experiments showed that electroneutral quaternization/sulfosuccination of starch were able to alleviate the negative effect of paste ageing on the elongation, work at break, and flex-fatigue resistance, thereby obviously enhancing the elongation, work at break and flex-fatigue resistance, and thus reducing the drawback of brittleness. The enhancement depended on the amounts of the substituents introduced. With the increase in DS value, the elongation and work at break as well as flex-fatigue resistance continuously rose, whereas the tensile strength gradually reduced.

Preparation and antibacterial properties of polycaprolactone/quaternized chitosan blends

This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus,were conducted.Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone(PCL).Inhibition rates of polycaprolactone/quaternized chitosan were 39.2%99.9%against Escherichia coli,while inhibition rate was 40.9%99.9%against Staphylococcus aureus.When quaternized chitosan(QCTS)content was up to 20%,blends exhibited 99.9%inhibition rates against both two types of bacteria.

Homogeneous Synthesis and Characterization of Quaternized Cellulose Derivatives in NaOH-urea Aqueous Solutions

Quaternized cellulose( QC) derivatives were synthesized by reacting cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride( CHPTAC) in an aqueous solution of Na OH-urea. The chemical structures and physical properties of the obtained QC derivatives were characterized using nitrogen content analysis,Fourier transform infrared spectroscopy( FT-IR),~1H-nuclear magnetic resonance(1H-NMR),X-ray diffraction( XRD),and thermal gravity analysis( TGA). The FT-IR and ~1H-NMR results confirmed the successful introduction of cationic quaternary ammonium groups into the main chain of cellulose. A series of QC derivatives with the degree of substitution( DS) values ranging from 0. 33 to 0. 80 were derived by adjusting the molar ratio of CHPTAC to anhydroglucose unit( AGU) of cellulose,concentration of cellulose in the Na OH-urea solution,as well as reaction temperature and time. According to the DS values of the QC derivatives,the optimized synthetic conditions were as follows: 25℃ reaction temperature,3% cellulose in Na OH-urea solution,the molar ratio of etherification agent to glycosidic cellulose of 15∶ 1,and 12 h reaction time. The TGA and XRD results revealed that the crystalline structure was destroyed during etherification,and the thermal stability of the QC derivatives was lower than that of cellulose.

Quaternized polymer binder for lithium-sulfur batteries:The effect of cation structure on battery performance

Lithium–sulfur (Li–S) batteries are great candidates for energy storage systems, but need to overcome theissues of low sulfur utilization and polysulfide shuttling for use in large-scale commercial applications.Recently, quaternized polymers have received much attention for their polysulfide trapping propertiesdue to electrostatic interaction. In this work, we report a series of polyarylether sulfone (PSF) binderswith different cation structures including imidazolium (Im), triethylammonium (Tr), and morpholinium(Mo). The ability of the these quaternized binders and the conventional poly(vinylidene fluoride) or PVDFbinder to capture polysulfide increases in the order of PVDF << PSF-Mo < PSF-Tr< PSF-Im. The delocalizedcharge on the imidazolium cation may promote the interaction between PSF-Im and polysulfide asindicated by an X-ray photoelectron spectroscopic study. The PSF-Im based cathodes showed the highestcapacity retention (77% at 0.2 C after 100 cycles and 84% at 0.5 C after 120 cycles), and the bestrate capability. This work demonstrates the importance of the cation structure in the design of efficientquaternized binders for high performance Li–S batteries.

The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid

Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.

Synthesis of Chitosan Quaternary Ammonium Salts

A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, (HNMR)-H-1 and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

Immunostimulatory eff ect of quaternary degree and acetyl group of quaternized chitosan on macrophages RAW 264.7

Hydroxypropyltrimethyl ammonium chloride chitosan(HACC)and hydroxypropyltrimethyl ammonium chloride fully deacetylated chitosan(De-HACC)were synthesized with various degrees of substitution by altering the ratio of chitosan to glycidyl trimethyl-ammonium chloride(GTMAC).The effects of the quaternary ammonium degree and the acetyl group of these polymers on immunostimulatory activities were detected in RAW 264.7 cells.The expression levels of nitrogen oxide(NO),interleukin-6(IL-6)and tumor necrosis factor(TNF-α)were compared.Results show that the removal of acetyl groups in chitosan obviously improved the degree of substitution of quaternary ammonium salts.In addition,HACC and De-HACC were capable of promoting immunological activity in a substitution-dependent manner;HACC was positively correlated,and De-HACC was negatively correlated.Among tested ratios,HACC-30%and De-HACC-54%performed better than the others,and De-HACC-54%performed the best.Generally,quaternized chitosan possesses immunostimulatory activity,which is related to the degree of quaternization and the acetyl group.

Surface Properties and Compatibility with Blood of New Quaternized Polysulfones

The paper describes some properties of new quaternized polysulfones obtained by quaternization of chloromethylated polysulfone with different tertiary amines - N,N-dimethylethylamine and N,N-dimethyloctylamine. Hydrophilic/hydrophobic properties, morphological aspects and compatibility with red blood cells and platelets are affected by the alkyl radicals and by history of the formed films. The results obtained are useful in biomedical applications, including evaluation of bacterial adhesion to the surfaces, or utilization of modified polysulfones as semipermeable membranes.

Nuclear-Chemical Synthesis of 1,4-Diazine Quaternary Salts

Ion-molecular reactions of nucleogenic phenyl cations with the nucleophilic centers of 1,4-diazines have been investigated for the first time. Previously unknown tritium labeled N-phenyl quaternary derivatives of pyrazine and quinoxaline, which are potential radioactive biomarkers, have been obtained by nuclear-chemical method.

“四位一体”目标下小学体育教学学生自我评价研究

为使新时代学校体育“四位一体”目标切实落地实施,文章在对中小学体育教学学生自我评价必要性分析的基础上,对评价内容的依据和原则进行全面探究,并建构了学生自我评价内容的5个层级;进一步提出基于“四位一体”体育教学学生自我评价不但是实现新时代“立德树人”根本任务不可替代的新路径,而且也是后冬奥时代,中国中小学奥林匹克教育可持续开展的中国本土化创新路径。

季铵化改性PAM及其在完井液废弃物处理中的应用

海上完井作业过程中产生的废弃物组成复杂,对环境危害巨大,开展海上完井液废弃物无害化处理及资源化利用具有重要意义。以聚丙烯酰胺(PAM)、氯化缩水甘油基三甲基铵(GTMAC)为原料合成了一种新型季铵化聚丙烯酰胺(PAMQ),其同时具有助凝和缓蚀效果。絮凝实验结果表明,在完井液废弃物中加入300 mg/L PAMQ后,聚合氯化铝(PAC)的絮凝效率明显提高。腐蚀实验结果表明,PAMQ具有良好的抑制低碳钢CO_(2)和NaCl腐蚀的性能,当PAMQ添加量为1 000 mg/L时,缓蚀率为87.60%。PAMQ分子的支链结构可有效聚集完井液废弃物中的游离不溶物,同时季铵基团的正电荷可有效中和废弃物的负电荷,促进其絮凝。PAMQ分子中含有的氨基及季铵基团可与碳钢表面发生强相互作用而吸附在碳钢表面形成吸附膜,阻止腐蚀溶液与碳钢表面的接触,从而抑制腐蚀。PAMQ极大地提高了油田化学品药剂的使用效率,可达到节约成本和提质增效的作用。

论“训研创服”四位一体高职实践育人体系的构建

在我国,知行合一、实践育人的思想源远流长并不断传承。自从十九届五中全会提出“增强职业技术教育适应性”以来,实践育人在增强高职学生社会适应性中发挥着更加重要的作用。当前,职业教育实践育人仍存在育人主体单一化、育人环节薄弱、育人过程系统性规划缺乏等问题。基于构建实践育人体系的价值取向,应构建以立德树人为根本,以专业实践和综合实践育人两大内容为主体的“训研创服”四位一体实践育人体系,以推进全面实践育人、增强职业教育社会适应性。

一种新型聚合物VDE用于快速吸附水中的硝酸盐

针对水中硝酸盐污染的问题,合成一种新型的聚合物乙烯基咪唑/二溴癸烷/二甲基丙烯酸乙二醇(VDE),通过扫描电子显微镜(SEM)、Fourier变换红外光谱仪(FT-IR)和X射线光电子能谱(XPS)对其结构进行表征,并研究其在含硝酸盐水溶液的最佳剂量比、pH值、吸附温度、吸附时间以及重复利用性.结果表明,在15℃,pH=4时,VDE对硝酸盐氮的吸附量通过Langmuir模型拟合为28.31 mg/g,该吸附过程在10 min可达到平衡,且符合准一级和准二级动力学拟合模型,在5次吸附/脱附实验后,其吸附量仍可达到首次使用吸附量的95.5%,表明该材料可有效净化低质量浓度的硝酸盐废水.