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关键词： 研究生入学考试   《物理化学》   交叉融合   教学团队   化学化工   哈尔滨工业大学   概念抽象   核心课程  

摘要： 《物理化学》被誉为"化学中的哲学",化学化工核心课程中的"天书",为数理化三科交叉融合,体系庞大,逻辑性强,概念抽象,公式多、逻辑变换复杂等特点被认为是"教师最难教、学生最难学"的课程。其为化学化工类研究生入学考试必考课程,课程内容全面且后续分化为化学与化工各个专业,同时还支撑多个相关学科体系。

关键词： 物理化学   课程思政   教学融合  

摘要： 物理化学是各大高校一门重要的理工类专业基础课程,课程本身包含了丰富的思政元素。本文着重阐述了专业育人与思政育人相结合的重要性,并以物理化学课程教学为实例,从课程思政教学理念下教学大纲的修订,教学内容整合及教学方法的设计、科研实验室的建设等方面提出了几点具体的教学融合的策略,希望能对同类型的专业课的课程思政教学改革工作提供一些实用的参考价值,推动高校课程思政工作的进行。

关键词： Densities and viscosities   Vit.C   Vit. B-1   Vit.B-3   Vit. B-6   Magnesium chloride  

摘要： Vitamins are the precursors of many coenzymes essential for biocatalysts and their deficiency leads to diseases in masses. The vitamins are very fragile and can easily be destroyed with change external atmosphere. Electrolytes are inherent constituents of cytoplasm and are required in variety of biochemical functions. The interactions occurring between, solute-cosolute and solvent can be inferenced and interpreted from thermodynamic and transport studies effectively which will help in interpreting the mechanism of vitamins in solution phase. In the present study apparent molar volume phi(V), and viscosity B-coefficient B, have been determined for L-ascorbic acid (Vit.C), nicotinic acid (Vit.B-3), thiamine hydrochloride (HCl salt of Vit. B-1) and pyridoxine hydrochloride (HCl salt of Vit. B-6) in aqueous magnesium chloride solutions (m(B) = 0.1 to ***(-1)) over the temperature range (288.15-318.15) K at pressure (101.3) kPa. The partial molar volume of transfer, Delta(tr)phi(o)(V), and viscosity B-coefficient of transfer, Delta B-tr, for these compounds from water to aqueous solutions of magnesium chloride have been determined from the corresponding data. First (partial derivative phi(o)(V)/partial derivative T) (P) and second (partial derivative(2)phi(o)(V)/partial derivative T-2)(P), derivative of phi(o)(V) and dB/dT, values have been calculated. B/phi(o)(V) ratio, activation free energy of viscous flow of vitamins Delta mu(o#)(2), and other parameters have also been calculated. Both volumetric and viscometric studies suggest the presence of complex interactions at lower concentrations, but the role of cosolute becomes decisive at higher concentrations. The dB/dT values and activation parameters (Delta S-2(o#), Delta H-2(o#)) values suggest that L-ascorbic acid, thiamine hydrochloride and pyridoxine hydrochloride show bond making tendencies with magnesium chloride while nicotinic acid shows comparatively less affinity with magnesium chloride. (C) 2021 Elsevie

关键词： biomaterials   CaP coatings   magnetron sputtering   hydroxyapatite   biocompatibility  

摘要： Thin calcium phosphate (CaP) coatings were deposited on titanium substrates by radio frequency magnetron sputtering of hydroxyapatite target in neon (Ne), argon (Ar), krypton (Kr) and xenon (Xe). The influence of the working gas (Ne, Ar, Kr and Xe) on the wettability and biodegradation in the RPMI 1640 synthetic culture medium of the CaP coatings was investigated. This paper is the first comprehensive study of working gas effect on properties of the CaP coatings. There was an increase in the polar component of surface free energy (SFE) and a decrease in the dispersion component of SFE with an increase in the atomic mass of the working gas. All CaP coatings had a pronounced protective effect, reducing double the number of dead cells in culture compared to the Ti control. The most soluble CaP coatings formed in the atmosphere of Xe stimulated the hAMMSCs division, which led to an increase in the total number of cells (208% of the initial culture). Samples with CaP coatings formed in an inert gas atmosphere increased the gene expression (ALPL, BMP6, BMP2) in vitro. The most biocompatible coatings were those formed in the atmosphere of Xe and Ar.

关键词： bread‐   making   experimental flour milling   millstreams   wheat quality  

摘要： Background and Objective Limited data have been reported on the evaluation of physicochemical characteristics in millstreams (MS) obtained from large-scale mills for hard red spring (HRS) wheat. Therefore, this research was designed to evaluate the MIAG-Multomat mill that is a large-scale experimental mill imitating the commercial flour mills. Findings The MIAG-Multomat mill yielded different trends across MS for ash and arabinoxylan. Specifically, reduction MS had lower ash content but higher arabinoxylan content than break MS. Moreover, arabinoxylan and other factors such as damaged starch content and coarse particle (over 600-mu m) percent had significant (p < .05) correlations with bread-making traits including mixograph peak time, water absorption, and bread loaf volume, while ash had nonsignificant correlations with these quality traits. Conclusions This research investigated the influence of physicochemical characteristics on bread-making quality for the MIAG-Multomat MS. Overall, the arabinoxylan, starch damage content, and coarse particle percent rather than flour ash content were identified as primary physicochemical components to influence variation of bread-making traits for MIAG-Multomat MS for HRS wheat. Significance and Novelty The knowledge on composition of MS obtained in this research is valuable to optimize the functionality of flour blends, especially, in the long-flow milling of HRS wheat.

关键词： Extrusion  

摘要： In this study, the effect of concentrations of corn starch and whey protein isolate was evaluated on the processing parameters and the physicochemical characteristics of the extrudates, using a Lattice simple mixture design. A variation from 10.02 to 68.81 g/min is observed in the residence time of the corn starch (CS)/whey protein isolate (WPI) blends and increased as WPI was higher, the torque ranged from 4.18 to 48.83 Nm/s, which decreases with the increase in WPI;the specific mechanical energy was between 247.85 and 882.92 J/g, and also the expansion index was between 0.92 and 1.40, which was decreasing with the rise in WPI, whereas the bulk density was between 0.14 and 0.42 g/cm(3) presenting the same trend. The hardness ranged between 44.50 and 86.12 N. The results showed the importance of extrusion on the interactions that occur between CS/WPI concentrations and how these interactions influence the processing parameters and the physicochemical characteristics of the blends. Practical applications Because starch and protein are two of the main components of most foods, knowing how these interact on the processing parameters and the physicochemical characteristics in extrusion cooking is important. In addition to extrusion cooking, it is widely used in the food industry, in which these components/ingredients notably influence the characteristics of the final product. These results are lucrative for the food industry that make products based on whey protein and starch, as they serve to optimize the composition and improve the nutritional value of the final product.

关键词： Lecithin   Phospholipids   Botanical origin   Micelles   Liposomes   Emulsions  

摘要： Background: Lecithin is widely used as an ingredient in the food industry due to its diverse functionality, mainly attributed to phospholipids (PL), the principal constituents. However, a systematic understanding of the functional properties of lecithin ingredients is missing in the literature. Scope and approach: This review outlines recent developments in lecithin from botanical origin and reviews the complex inter-relationships between physicochemical properties of PL in lecithin and selected techno-functional properties in micelles, liposomes and oil-in-water emulsions. Key findings and conclusions: Attributed to their polar phosphatide group and non-polar fatty acids, PL have specific molecular geometries, dissociation constants and charge, which strongly influence their functional properties in micelles, liposomes and oil-in-water emulsions. The PL profile and extrinsic factors (e.g., water, oil, hexane) influence the formation of micelles during separation of lecithin from oil using membrane filtration. In liposomes, PL profile and the presence of surface modifiers (i.e., sterols) affect the particle size and encapsulation efficiency. In emulsion systems, PL and their interaction with minerals and other functional ingredients (e.g., proteins), influence the particle size and physical stability of the oil droplets. This work provides an integrated review of the links between the composition and physicochemical properties of PL, and in turn, scientifically underpins the links between physicochemical and functional properties of lecithin.

关键词： Moisture  

摘要： Boneless Tuna chunks were marinated using spices and were dried in a microwave vacuum dryer at different powers (600 W [T1], 650 W [T2], and 700 W [T3]) for 2 hr. Another two batches were prepared by hot air drying (55 +/- 5 degrees C) (HAD) and sun drying (SD) to a comparable moisture content obtained by sample T2. The moisture content was 44.69 g/100 g, 39.26 g/100 g, 24.40 g/100 g, 32.80 g/100 g, and 38.45 g/100 g for T1, T2, T3, SD, and HAD, respectively. Increasing microwave power level resulted in reduced moisture content and water activity in dried tuna chunks. Analysis of SEM indicated a tough morphology in SD and HAD whereas a smooth morphology in microwave vacuum dried samples. Results of FTIR analysis indicated higher protein denaturation with an increase in microwave power. Oxidation of lipids increased significantly (p < .05) with microwave power as displayed by higher peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) values in T3 and T2 samples. Microbial spoilage was faster in T1 samples compared to T2 and T3. On the other side, sun-dried and hot air-dried samples have shown poor rehydration and color attributes but better oxidative stability than microwave vacuum dried samples. Practical applications Conventional methods of fish drying have several drawbacks including longer duration of drying, poor sensory properties, low rehydration abilities, etc. Microwave vacuum drying is a novel drying technology that enhances the end product quality of dried fish by using the advantages of both microwave and vacuum for rapid dehydration. It is very essential to evaluate the properties of food products developed by any processing method and the present study gives information on the influence of microwave power on the product quality during drying. The present study also provides the information on effects of different drying methods on the physico-chemical qualities of dried Tuna chunks. The results of the study will definitely benefit fi

关键词： Phlebopus portentosus protein isolate (PPI)   Physicochemical property   PPI nanoparticle (PPIP)   Emulsifying property   Double emulsion  

摘要： Edible mushroom proteins have attracted increasing interest due to their high content and nutritional quality. In the present work, Phlebopus portentosus protein isolate (PPI) was extracted from P. portentosus fruiting bodies using alkali extraction and isoelectric precipitation method, and the physicochemical and emulsifying properties of PPI were systematically investigated. PPI had a good balance of essential amino acids, but showed low solubility in water. Therefore, a protein nanoparticulation strategy was used to prepare stable PPI nanoparticle (PPIP) dispersions. PPIP showed an average diameter of 225.91 nm, an oil-in-water three-phase contact angle (theta(o/w)) of 95.62 degrees, and fast adsorption behavior at the oil-water interfaces. The near-neutral wettability and high interfacial ability facilitate PPIP as a single emulsifier to fabricate a double Pickering emulsion via the one-step homogenization. The properties of PPIP-stabilized double emulsions were dependent on the protein concentration and oil content. For example, an increase in protein concentration resulted in the decrease of small internal droplet number, droplet size, and storage modulus;an increase in oil content also led to the decrease in the droplet size. These results suggest that PPI has a great potential to be used as emulsifiers for preparing double emulsions.

关键词： Silver nanoparticles   Psidium guajava   Tamarindus indica   Green synthesis   Antifungal effect  

摘要： The green synthesized silver nanoparticles get much attention because of less toxicity, friendly environmental method, and their potential properties in various applications. Herein, the silver nanoparticles named as ***-AgNPs or ***-AgNPs are respectively fabricated by the oxidation-reduction reactions between silver ion and Psidium guajava or Tamarindus indica leaf extract. The Ultraviolet-visible spectrum of ***-AgNPs appears the 429-nm peak while the peak of ***-AgNPs is at 491 nm. The transmission electron microscopy and scanning electron microscope images show the ***-AgNPs are spherical, triangular and plate-like polyshaped morphology in 5-53 nm, the ***-AgNPs have spherical shape in 12-91 nm. The Fourier transform infrared spectra reveal that the particle surface contains the organic functional groups that is consisted with the elemental analysis from the energy dispersive X-ray analysis indicating the presence of C, O and Ag. So the Psidium guajava leaf extract containing abundant polyphenols, polyols, aldehyde content, and sulfur compounds creates the ***-AgNPs with smaller size, narrower distribution, more diversified morphology than ***-AgNPs fabricated from Tamarindus indica leaf extract being rich of organic acid and vitamin C. In addition, ***-AgNPs and ***-AgNPs show the highly antifungal ability against Fusarium oxysporum, Aspergillus niger, and Aspergillus flavus.