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关键词： 研究生教学   教学有效性   线上课程设计   教学过程管理   表面物理化学  

摘要： 在疫情防控常态化的新形势下,加强研究生课程的线上教学,对于保证高水平人才培养质量具有重要意义。文章从线上课程设计、教学过程管理、考核设计和教学效果等方面,对哈尔滨工业大学研究生精品课程表面物理化学的线上教学有效性进行了分析和总结,以期为高校研究生在线开放课程建设提供借鉴。

关键词： Dragon fruit   foam mat drying   ascorbic acid   antioxidant capacity   betalains  

摘要： Pitaya is a perishable fruit with a high content of bioactive compounds. This study aimed to evaluate the influence of ethanol pretreatment (95% dripped on the surface of the foam at a rate of 0.05 ***(-2)) and temperature (50 and 70 degrees C) on moisture content, water activity, solubility, color, ascorbic acid, antioxidant capacity (DPPH and FRAP) e betanin and betaxanthin retention of white and red pitaya powdered pulps and to determine an optimal process condition. Pretreatment and higher temperature resulted in increased solubility and antioxidant capacity of powdered pulps. The total color difference was influenced by pretreatment and drying temperature, but in different ways according to the variety. In the pretreated red pulp powders, 70 degrees C resulted in higher retention of ascorbic acid and 50 degrees C resulted in increased retention of betanins and betaxanthins. The optimal treatment for white and red pulps was the use of pretreatment and a temperature of 70 degrees C.

关键词： 物理化学   聚叠氮缩水甘油醚   GAP   PET   嵌段热塑性弹性体   低温力学性能  

摘要： 为改善聚叠氮缩水甘油醚(GAP)基黏合剂的低温力学性能,以GAP和环氧乙烷-四氢呋喃共聚醚(PET)为软段,甲苯-2,4-二异氰酸酯(TDI)偶联的丁二醇为硬段,通过扩链聚合反应合成GAP/PET嵌段型热塑性聚氨酯弹性体;分别采用红外光谱(FT-IR)、核磁共振(NMR)、差示扫描量热分析(DSC)、动态热机械分析(DMA)、热重分析(TGA)和万能材料试验机对其化学结构、玻璃化转变温度、热稳定性和低温拉伸性能进行表征。结果表明,随着PET含量的提高,GAP/PET嵌段型热塑性聚氨酯的T_(g)明显降低,当PET与GAP摩尔比为1∶1时,GAP/PET嵌段型热塑性聚氨酯的T_(g)为-37.7℃,在-40℃低温环境发生韧性断裂,断裂强度为25.78MPa,断裂伸长率为379.4%,具有优异的低温力学性能;同时TGA试验表明GAP/PET嵌段型热塑性聚氨酯T_(d)>220℃,热稳定性好。

关键词： Enterobacteriaceae   Biogenic amines   Suan yu   Strain effect   Inoculation  

摘要： The formation of biogenic amines (BAs) is an important potential danger in traditional fermented fish (Suan yu), and Enterobacteriaceae play an important role in the formation of BAs. The amine production abilities of 97 strains of Enterobacteriaceae screened from traditional fermented Suan yu were analyzed by reversed-phased high-performance liquid chromatography (HPLC). The genotypic diversity of amino acid decarboxylase on 23 strains of high-yield BAs was verified by PCR. Enterobacteriaceae with the highest production of amines was determined by analysis of the effects of physicochemical factors (pH, NaCl, temperature, and aerobic/anaerobic) on BA production and principal component analysis (PCA). The adaptability of the strains was examined using surimi simulation fermentation system, and the correlations among the indicators were analyzed using Cyto-scape. Results showed that 97 strains of Enterobacteriaceae had strong amine-producing ability. Furthermore, 23 strains producing high yields of putrescine, cadaverine, and histamine were identified. All of the strains carried Idc, odc, speA, speB, and adiA, and five strains carried hdc. pH mainly affected the BA production of amine-producing bacteria. Three strains (Enterobacter asburiae 26C3, Klebsiella pneumoniae 47C2, and Morganella mor-ganii 45C3) had the best amine-producing ability and used as the inoculated group. In this group, the values of BA (228.70-290.05 mg/kg) and the total volatile base nitrogen (TVB-N, 173.87-221.87 mg/100 g) exceeded the limit. Moreover, myofibrillar protein degradation was significant as indicated by the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and decreased FAA content. Cytoscape software and principal component analysis (PCA) indicated that Enterobacteriaceae and pH were related to BA formation in Suan yu. These results provide a theoretical basis for controlling the BA of fermented fish products.

关键词： 物理化学   TKX-50   纳米铝粉   静电喷雾法   含能微单元   感度  

摘要： 为了获得钝感和组分均匀的含能微单元,采用静电喷雾法制备了TKX-50/Al/GAP复合微球;采用扫描电镜(SEM)、X射线能谱(EDS)、X-射线衍射仪(XRD)和红外光谱仪(FT-IR)对其形貌结构进行了表征;采用差示扫描量热仪(DSC)测试了热分解性能;采用高速摄影仪测试其点火燃烧性能;根据GB/T 21567-2008、GB/T 21566-2008标准对其感度进行了测试。结果表明,静电喷雾法制备的TKX-50/Al/GAP含能微单元组分分布均匀,为粒径2~3μm的微球;与物理混合法相比,微球的表观分解热提高了860.7J/g,活化能升高了12.07kJ/mol,;静电喷雾法制备的微球点火延迟时间为11ms,燃烧时间为409ms;撞击、摩擦和静电感度与物理混合样品相比,分别降低了83J、80N和0.05J,表明静电喷雾法制备的TKX-50/Al/GAP含能微单元具有良好的安全性能。

关键词： 物理化学   思政元素   分类与融合   课程思政  

摘要： 根据思政元素所表达的主题和育人意义,把“物理化学”课程教学中存在的思政元素划分为家国情怀、社会责任、科学态度三个类别,并对其关系进行了探讨,有助于把握好课程教学内容与思政元素的关系,能够更加有效地提炼和应用课程思政元素,全方位落实课程的培养目标。

关键词： Liposomes   Hydrolysable tannins   Physicochemical analysis  

摘要： Tannins belong to plant secondary metabolites exhibiting a wide range of biological activity. One of the important aspects of the realization of the biological effects of tannins is the interaction with lipids of cell membranes. In this work we studied the interaction of two hydrolysable tannins: 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) and 1,2-di-O-galloyl-4,6-valoneoyl-beta-D-glucose (T1) which had the same number of both aromatic rings (5) and hydroxyl groups (15) but differing in flexibility due to the presence of valoneoyl group in the T1 molecule with DMPC (dimyristoylphosphatidylcholine) lipid nano-vesicles (liposomes). Tannins-liposomes interactions were investigated using fluorescence spectroscopy, differential scanning calorimetry, laser Doppler velocimetry, dynamic light scattering and Fourier Transform Infra-Red spectroscopy. It was shown that more flexible PGG molecules stronger decreased the microviscosity of the liposomal membranes and increased the values of negative zeta potential in comparison with the more rigid T1. Both compounds diminished the phase transition temperature of DMPC membranes, interacted with liposomes via P=O groups of head of phospholipids and their hydrophobic regions. These tannins neutralized DPPH free radicals with the stoichiometry of the reaction equal 1:1. The effects of the studied compounds on liposomes were discussed in relation to tannin quantum chemical parameters calculated by molecular modeling.

关键词： Spray-drying   dromedary milk   water activity   particle size distribution   rehydration ability   SEM  

摘要： The aim of this study was to evaluate the effect of air outlet temperature (75 and 85 degrees C) and milk type on proximate composition, water activity, particle size distribution, color, and rehydration ability of spray-dried skim dromedary and cow's milk powders. While the water activity of powders was close to 0.4 when spray-dried at 75 degrees C air outlet temperature, it ranged from 0.2 to 0.3 for a production at 85 degrees C air outlet temperature. Skim dromedary milk powder had a lower water activity than skim cow's milk powder after spray-drying at 85 degrees C air outlet temperature. Spray-drying yields were greater at the higher air outlet temperature (85 degrees C) for both skim milk powders. The particle size distributions of spray-dried skim milk powders were centered around 14-20 mu m. The particles of skim dromedary milk powders were smaller than those of skim cow's milk powders as skim dromedary milk was less viscous, leading to smaller sprayed droplets. No significant influence of spray-drying conditions on particle size distribution was observed for dromedary milk powders. Regardless of the spray-drying conditions and the milk type, the produced powders were very bright and had a low color saturation. Scanning electron microscopy images showed that spray-dried powders appeared as agglomerates of small particles with angular shapes rather than individual particles. All investigated spray-dried powders were considered non-wettable, hardly dispersible, and fairly soluble. Skim dromedary milk powder produced at 85 degrees C air outlet temperature showed a significantly higher solubility index than the same formulation spray-dried at 75 degrees C outlet air temperature. The opposite was obtained for skim cow's milk powder. These results demonstrated that the outlet drying air temperature significantly influenced water activity, spray-drying yield and solubility of spray-dried dairy powders.

关键词： 课程思政   新工科人才培养   物理化学   课程改革  

摘要： 新能源技术的发展对新工科人才培养提出了新要求,推动着相关专业教学模式的变革。基于课程思政理念设计的工科类专业的课程体系,可以促进学生工程实践能力的提升。物理化学是一门理论基础课,包含了丰富的思政内容,教师需不断挖掘思政元素。在新时代教育改革背景下,本文根据物理化学课程特点,将思政元素融于课程知识教学过程中,润物细无声,引导学生树立科学的价值观和人生观。

关键词： Titania-containing slag   Physicochemical property   Prediction model   Slag structure  

摘要： The titanium industry can hardly bypass the titania-containing slags,and the slag physicochemical properties are essential in the metallurgical reactor design and process *** TiO_(2)–FeO-based slags and TiO_(2)–SiO_(2)–CaO-based slags are the main metallurgical slag systems in the titanium resource utilization *** elaborate the role of TiO_(2) in the physicochemical properties of titania-containing metallurgical slags,the physicochemical properties including titanium redox ratio,liquidus temperature,viscosity,electrical conductivity,density,surface tension,thermal conductivity,and sulfide capacity were critically ***,the property prediction models were briefly introduced with regards to the limitations of the existing *** property prediction models are still required to evolve since not all properties of titania-containing slags can be well *** the slag structure has an intimate relationship with slag properties,the structural details of the titania-containing slag were investigated by using a combination of spectroscopic technologies,but the knowledge of the slag structure was not fully *** potential research fields related to the physicochemical properties and structure of the titania-containing slags were also suggested.