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关键词： 物理化学   异形发射药   药形   内弹道性能模拟   燃烧性能   燃烧渐增性  

摘要： 针对内弹道性能模拟对发射药燃烧表面积计算的需求,提出了一种异形发射药药形计算与设计方法;设计了三角形柱状、梯形柱状和四边形柱状发射药,利用切分-独立计算-整体加和的计算原理,对其面积及体积随燃烧深度变化规律进行了计算;根据几何燃烧定律,推导了燃气生成猛度与发射药已燃百分数之间的函数关系,并讨论了内孔径对发射药燃烧渐增性的影响;对12孔梯形柱状发射药进行了试验验证。结果表明:异形发射药在内外弧厚保持一致、长宽比保持不变基础上,其理论燃烧过程呈增面燃烧的趋势,且随着孔径减小燃烧分裂点后移,但孔径变化对发射药燃烧过程影响有限。12孔梯形发射药的实际燃烧过程具有燃烧渐增性,但由于实际发射药尺寸以及点火一致性的偏差,测试结果与理论计算结果有一定误差。

关键词： Biochar   Soil fertility   Mesofauna   Roots   Earthworms   Pasture  

摘要： Biochar application has been recognised as an effective way to improve soil functions. In this study, we investigated how adding biochar as an amendment affects soil biological and physico-chemical properties in grazed pastures in a one-year field-based mesocosm experiment conducted on two contrasting soils - a sil-andic Andosol and a dystric Cambisol. Each site had two pastures managed under different nutrient and livestock practices: with and without effluent under dairy cow grazing on the Andosol, and with either nil or high phosphorus (P) fertiliser input under sheep grazing on the Cambisol. The soil amendment treatments were: (i) willow biochar produced at 3508 degrees C (1% w/w);(ii) lime, added at the liming equivalence of the biochar application (positive control);(iii) no amendments (negative control). With few exceptions, after 12 months and compared with initial values and controls, biochar caused (i) an increase in soil total nitrogen (N) and Olsen P content (all P < 0.005) beyond those expected from the N and P added with biochar;(ii) decrease in soil bulk density (P < 0.005), on average by 7%, more than can be explained by the reduced density of the biochar added;(iii) increase in microbial biomass C (P < 0.005), and (iv) increase in root biomass by 6.9 Mg ha(-1) (P < 0.005). Lime addition increased pH values in both soils under all four management practices, and increased earthworm abundance compared with controls across all sites. In biochar-amended soils, earthworm abundance was higher only in the Andosol without effluent (P < 0.05), while Collembola abundance was significantly higher (P < 0.005) than the controls in all pastures;there was no effect on soil Oribatida and Gamasina populations. Adding biochar made from willow wood produced at low temperature to these pasture soils can positively affect the soil structure, nutrient cycling, and stimulate root growth, a key contributor to organic C input to the soil and the soil food web.

关键词： 过程性考核   物理化学   蓝墨云班课  

摘要： 近年来,随着“以学生为中心”教育理念的深入人心,过程性考核逐渐引起教育工作者的重视。针对目前物理化学考核模式存在的问题,以蓝墨云班平台为基础,对物理化学课程的过程性考核进行了实践研究,通过对考核方法及内容的精心设计,构建了以学生为主体动态跟踪的过程性考核模式,激发了学生的学习主动性和学习热情,对提升物理化学课教学质量起到了积极促进作用。

关键词： 混合式教学   物理化学   教学流程   评价体系   教学效果  

摘要： 优化物理化学的教学方法不仅有利于提升学生的学习积极性,还可以帮助学生完善学习方法,进而发挥学生的学习主动性,提升课程教学效果。我们以“超星”为媒介,将线上课堂和线下课堂有机结合,形成优势互补,不仅丰富了教学内容,完善教学方法,更是进一步强调学生的主体地位以及提升学生的学习能动性,进而促进教学效果的提升。

关键词： Pulse proteins   Legume proteins   Plant proteins   Characterisation   Functionality   pH-dependency  

摘要： Red lentils (Lens culinaris) present an attractive raw material for meat mimics due to its red-coloured proteins, abundance, high protein and low cost. However, data on its functional properties at various pH remain scarce. In this study, the physicochemical and functional properties of red lentil proteins (RLP) from three origins (USA, Nepal and Turkey), isolated by isoelectric precipitation, were evaluated. Amino acid profiles, water holding (ranging from 3.1 to 3.5 g/g) and oil absorption (ranging from 5.8 to 7.3 g/g) capacities of RLP samples were significantly different (p < 0.05). RLP consisted of legumin and vicilin, and comprised predominantly glutamine/ glutamic acid (ranging from 8.72 to 10.55 g/100 g). Surface charge, protein solubility, foaming and emulsifying properties were the lowest and poorest at pH 5.2 (isoelectric point). Overall, good functional properties of RLP under high acidity and alkalinity conditions make it a promising protein for mimicking a wide range of meats.

关键词： 大米淀粉   淀粉纳米晶   可食用膜   物化性能  

摘要： 采用溶剂蒸发法制备蜡质玉米淀粉纳米晶(SNC)/大米淀粉复合可食用膜,研究SNC添加量对大米淀粉复合膜力学性能、水蒸气阻隔性、热稳定性和微观结构的影响。结果表明,不同SNC添加量的复合成膜膜液在稳态剪切试验中均呈现剪切变稀的行为,为假塑性流体。随着复合膜中SNC含量的增加,其拉伸强度呈现出先增大后减小的趋势;而复合膜的水蒸气透过率则呈现出相反的变化趋势。通过扫描电镜形貌图可知,在5%SNC/大米淀粉复合膜中SNC分散均匀。随着SNC添加量增加至15%,SNC在复合膜中形成了较大的团聚体。基于X-射线衍射和热重分析,研究发现SNC的适量添加可有效提高大米淀粉复合膜的结晶度和热稳定性。

关键词： 工程认证   物理化学实验   教学改革  

摘要： “物理化学实验”是化工、制药、食品、环境、生化、材料等工程类专业开设的一门必修课,是深入研究物质性质、物质变化规律的一门学科。基于工程认证要求,探讨了“物理化学实验”教学中存在的问题、教学改革的原则、方法及其效果。

关键词： Gradient precipitation   Chain length   Active compound   Stability   Micromorphology  

摘要： Three linear dextrins (LDs) with different chain length were obtained through fractionating short-chain LD by gradient precipitation with 65%, 70% and 75% alcohol, signed as 65LD, 70LD, and 75LD, respectively. The LDs were employed to encapsulate arachidonic acid (ARA) and geranic acid (GA). Fourier infrared spectrometry, differential scanning calorimetry and thermogravimetric analysis confirmed the formation of ARA/LD and GA/ LD composites. The ARA/65LD and GA/75LD composites showed higher crystallinity, indicating the formation of more ordered and compact structures in ARA/65LD and GA/75LD composites. The micromorphology of ARA/ 65LD composite was a clear ellipsoidal like structure, whereas GA/75LD composite presented a spherical shape. The release behavior, thermal, photochemical and antioxidant abilities of ARA and GA were improved after forming composites. Overall, the longer chain LD displayed better encapsulation efficiency with the longer chain ARA, while the shorter chain LD had higher encapsulation capability with GA.

关键词： 物理化学   HMX   高聚物黏结炸药   PBX   表面助剂   界面结合强度   降感   双向改性  

摘要： 为了增强HMX与黏结体系的界面结合强度,解决HMX基PBX炸药界面易脱粘的问题,设计了一种双向改性包覆HMX的方法来提升炸药与黏结体系间的界面稳定性;采用KH550对HMX进行改性,KH550、天然树脂、糊精、三(2-甲氧基氮丙啶)氧化磷(MAPO)4种表面助剂对TPU进行改性,制备了改性的HMX/TPU复合粒子;通过接触角测试仪、XPS、SEM、FTIR、感度测试仪对样品界面参数进行表征。结果表明,与单向改性的样品相比,KH550-KH550、KH550-MAPO、KH550-糊精双向改性样品的界面黏附功提高了31.1%~32.8%;双向改性后的样品包覆程度更高,其中KH550-MAPO双向改性样品表面的元素基团中—NO_(2)所占的比例较单向改性样品降低5.4%;双向改性样品的红外特征峰无明显变化;SEM结果表明,双向改性样品表面包覆更均匀、光滑;双向改性样品的摩擦感度较单向改性样品均有所降低。表明双向改性能针对性地对HMX与黏结剂界面结合进行修饰,改善其黏结性能。

关键词： Mulberry intercropped with alfalfa   Nitrogen application   Principal components analysis   Redundancy discriminators analysis   Rhizosphere soil  

摘要： Intercropping of mulberry(Morus alba L.)and alfalfa(Medicago sativa L.)is a new forestry-grass compound model in China,which can provide high forage yields with high *** application is one of the important factors determining the production and quality of this *** elucidate the advantages of intercropping and nitrogen application,we analyzed the changes of physicochemical properties,enzyme activities,and microbial communities in the rhizosphere *** used principal components analysis(PCA)and redundancy discriminators analysis to clarify the relationships among treatments and between treatments and environmental factors,*** results showed that nitrogen application significantly increased pH value,available nitrogen content,soil water content(SWC),and urea(URE)activity in rhizosphere soil of monoculture *** contrast,intercropping and intercropping+N significantly decreased pH and SWC in mulberry ***,intercropping and intercropping+N sharply reduced soil organic matter content and SWC in alfalfa ***,intercropping,and intercropping+N increased the values of McIntosh diversity(U),Simpson diversity(D),and Shannon-Weaver diversity(H’)in mulberry ***,PC A scatter plots showed clustering of monoculture mulberry with nitrogen(MNE)and intercropping mulberry without nitrogen(M0).Intercropping reduced both H’and D but nitrogen application showed no effect on diversity of microbial communities in *** were obvious differences in using the six types of carbon sources between mulberry and alfalfa *** and intercropping increased the numbers of sole carbon substrate in mulberry treatments where the relative use rate exceeded 4%.While the numbers declined in alfalfa with nitrogen and *** indicated that URE was positive when intercropping mulberry was treated with nitrogen,but was negative in monoculture alfalfa treated with *** pH and SWC were posi