Theoretical analysis and test verification of pull-out forces in shear connectors of composite beam under negative bending moment

Abstract

A mechanical model of steel-concrete composite beams considering horizontal slip and vertical pull-out effects under negative bending moment was established based on the theory of elastic deformation. By using the principle of force equilibrium and deformation compatibility condition, the differential equation was derived and deduced using computational calculation program, in which the formula of the pull-out force in shear connectors under negative bending moment was obtained. The experiment was conducted in order to verify the reliability of theoretical results. The results show: under the same load condition, the pull-out force of a single stud increases with the increase of the stud spacing. All the theoretical results were verified by comparing with experiment results to illustrate the accuracy and reliability of the calculation method. It provides a theoretical reference for the study of the interface interaction considering horizontal slip and vertical pull-out effect in the negative bending moment region of continuous composite beams.     

Isolation,purification, and characterization of the globulin from wheat germ

This research optimized the extraction and purification of globulin from wheat germ and assessed the molecular weight distribution and structure properties of the globulin obtained. The results showed that the relative extraction efficiency and purity of wheat germ globulin (WGG) reached 18.0% and 89.1% under the enzymolysis conditions of 0.32‰ α-amylase, pH 6.5, and 55 °C. The maximal precipitation rate of WGG (91.3%) was obtained with pH 4.3 (acid precipitation). Additionally, the molecular weight of WGG was mainly distributed below 70 kDa. FT-IR confirmed that random coils (30.95%), β-sheet (27.02%), α-helix (26.55%), and β-turn (15.48%) were the secondary structures of WGG. Furthermore, LTQ mass spectrometry showed that WGG was rich in variety and high in complexity, which retrieved 1274 proteins belonging to 392 proteomes by inverse peptide analysis. The findings endow a great potential of preparing WGG with superior functionality for food applications.     

Fe-N共掺杂NaTaO_3光催化材料制备和性能探究

通过水热法制得一系列Fe-N共掺杂的NaTaO3,对其进行了X-射线衍射(XRD)、扫描电子显微镜(SEM)、固体漫反射紫外-可见光谱(UV-Vis DRS)表征。XRD结果显示,掺杂之后NaTaO3晶胞略有膨胀,而颗粒尺寸略有减小。由UVVis DRS光谱推测可知掺杂之后的NaTaO3禁带宽度均小于未掺杂的NaTaO3禁带宽度。同时对其在254 nm紫外光区下光催化降解甲基橙溶液的性能进行了探究,其中Fe-N摩尔共掺杂量为0.15%的NaTaO3光催化活性最好。     

浅析项目教学法在物理化学教学中的应用

物理化学具有逻辑性强,系统性强,理论性强,概念抽象,公式多等特点,因此教与学的难度都很大。针对以往物理化学课程教学过程中存在的局限性,笔者提出了项目教学法,并应用于教学实践,以提高学生学习的主动性和解决实际问题的综合能力。     

聚丙烯酰胺-聚硅酸锌复合絮凝剂的制备和絮凝性能

利用物理复合的方法制备聚丙烯酰胺（PAM）-聚硅酸锌（PSZ）复合絮凝剂。结果表明,聚丙烯酰胺-聚硅酸锌絮凝剂在复配比例为V （PAM）： V （PSZ）=1.0、投加量为0.10 mL、模拟水样pH为8左右时,对高岭土模拟废水絮凝效果最好,脱色率达91.2%,均高于聚丙烯酰胺和聚硅酸锌单独使用的效果（最高脱色率分别达87.66%和89.78%）;而且,在中性和碱性范围内,这种复合絮凝剂受pH影响较小。三种絮凝剂应用于四种工业废水的脱色处理结果表明,聚丙烯酰胺-聚硅酸锌复合絮凝剂的脱色率也均比单一絮凝剂要高。     

发烟硫酸条件下环己酮肟贝克曼重排工艺进展

综述了环己酮肟在发烟硫酸条件下液相重排生成己内酰胺的相关新工艺、新设备及新技术,并对其进行了概括和分析.     

复合无机盐CuSO4/Fe2(SO4)3催化合成乙酸异戊酯

乙酸异戊酯通常在浓硫酸催化下由乙酸和异戊醇酯化制得,由于浓硫酸的氧化和脱水作用存在产品纯度低和色泽深等缺点,开发性能更加优良的酯化催化剂以代替硫酸成为研究热点。为考察复合无机盐催化剂CuSO₄/Fe₂(SO₄)₃合成乙酸异戊酯的催化性能,研究乙酸和异戊醇为原料在复合无机盐CuSO₄/Fe₂(SO₄)₃催化下的酯化反应,并考察催化剂用量、反应时间和乙酸与异戊醇物质的量比对乙酸酯化率的影响。结果表明,在乙酸用量0.1 mol、异戊醇用量0.2 mol、催化剂用量0.8 g、反应时间2.0 h和带水剂环己烷用量10 mL条件下,酯化率高于93%。催化剂具有催化活性高、操作简单和不污染环境等优点。     

2,3-吡啶二甲酸的合成

采用喹啉为原料,以高锰酸钾为氧化剂,以水为溶剂,经过氧化、浓缩、浓盐酸酸化、抽滤、干燥,合成了2,3-吡啶二甲酸,产率43.7%。     

应用型本科食品化学教学改革研究

食品化学是食品科学与工程专业的重要专业基础课,在课程教学中,课题组以培养应用型人才为目标,依据食品化学课程的性质和特点,对教学内容、多元化实践教学和考核评价体系及反馈体系的构建等方面进行了改革探索,努力构建"前沿、实践、创新"的教学模式,培养学生的实践能力和创新能力,促进应用型食品专业人才的培养,达到了食品化学课程教学的目的。