力学与土木工程专业的力学课程教学

文章在阐述力学学科的建立和发展、力学课程在土木工程专业的地位和作用的基础上,结合我院土木工程专业力学课程教学的现状,提出了将力学教学与实践教学、毕业设计相结合的教学改革方法,以提高教学和学习的效果。     

第28-32届奥运会投掷项目运动员年龄特征发展趋势研究

通过文献资料法、数理统计法、对比分析法以及个案分析法对第28-32届奥运会投掷项目前12名运动员的竞技年龄从结构、性别、年龄特征等角度进行对比分析。结果表明:(1)在28-32届奥运会投掷项目中,25-30岁年龄段运动员一直是奥运会投掷项目的主力军,在1-3名以及1-12名的人数占比中,一直呈增长趋势; 31岁以上年龄段运动员对奖牌仍具有较强的竞争力,在1-3名的人数占比中,整体呈现出增长的趋势。(2)在近5届奥运会中,投掷项目在整体上1-12名运动员平均年龄呈下降趋势;前3名运动员平均年龄发展呈现出增长趋势,女子运动员的平均年龄普遍低于男子运动员。(3)投掷运动员最佳竞技年龄表现出铁饼>链球>标枪>铅球(29> 28> 27.5> 27)的现象。(4)随着科技的助力以及科学的训练理念和方法的普及,国内外部分高水平投掷运动员能够较长时间的保持个人最佳竞技状态。     

运动调节肝脏能量代谢与抑郁症发病机制研究

抑郁症是一种常见的精神障碍性疾病,有研究表明肝脏能量代谢障碍与抑郁症发病密切相关。运动干预作为抑郁症的一种辅助治疗手段,其效果已得到认可和证实,然而作用机制尚未完全阐明。综述以运动调节肝脏能量代谢为主线,结合抑郁症的发病机理,阐明了抑郁症肝脏线粒体能量代谢障碍和运动干预改善抑郁症及肝脏能量代谢的积极效益,为抑郁症的运动疗法提供理论依据和实践参考。     

Injectable hybrid inorganic nanoscaffold as rapid stem cell assembly template for cartilage repair

Cartilage injuries are often devastating and most cannot be cured because of the intrinsically low regenerative capacity of cartilage tissues. Although stem-cell therapy has shown enormous potential for cartilage repair, the therapeutic outcome has been restricted by low survival rates and poor chondrocyte differentiation in vivo. Here, we report an injectable hybrid inorganic (IHI) nanoscaffold that facilitates fast assembly, enhances survival and regulates chondrogenic differentiation of stem cells. IHI nanoscaffolds that strongly bind to extracellular matrix (ECM) proteins assemble stem cells through synergistic 3D cell–cell and cell–matrix interactions, creating a favorable physical microenvironment for stem-cell survival and differentiation in vitro and in vivo. Additionally, chondrogenic factors can be loaded into nanoscaffolds with a high capacity, which allows deep, homogenous drug delivery into assembled 3D stem-cell-derived tissues for effective control over the soluble microenvironment of stem cells. The developed IHI nanoscaffolds that assemble with stem cells are injectable. They also scavenge reactive oxygen species and timely biodegrade for proper integration into injured cartilage tissues. Implantation of stem-cell-assembled IHI nanoscaffolds into injured cartilage results in accelerated tissue regeneration and functional recovery. By establishing our IHI nanoscaffold-templated 3D stem-cell assembly method, we provide a promising approach to better overcoming the inhibitory microenvironment associated with cartilage injuries and to advance current stem-cell-based tissue engineering.     

国内期刊创业研究十年回顾与展望

国内创业研究近十年来发展迅猛,呈现出主题相融、理论深入、方法多元的局面,并根植于中国的情境,在主题和理论方面体现出一定特色。已有多位学者对国际期刊上的创业文献进行了总结,然而还鲜有文章对国内期刊创业研究进行全面综述。本文基于过去十年在30本国内管理类主流期刊发表的1 308篇创业文献进行系统分析,通过扎根编码方法,从研究主题、研究方法、相关理论等角度进行剖析,呈现出国内创业研究的全貌。最后,根据分析结果提出了一个整合的创业研究理论框架,并指出未来创业研究的发展方向。     

区域一体化对城市创新能力驱动研究——基于长三角的实证分析

长三角更高质量一体化发展标志着各种资源要素在长三角区域内的配置效率将进一步提升,有利于形成更强的区域创新能力。本文基于2005—2017年长三角城市统计数据,考察了区域一体化对城市创新能力的驱动作用,并对其中的影响机制和异质性进行了深入分析。结果显示：(1)区域一体化对长三角城市创新能力具有显著的促进作用。(2)机制分析发现,一体化伴随的产业集聚并未形成创新能力提升机制,但一体化推动的区域内部产业转移机制有效提升了城市创新能力。(3)异质性分析表明,长三角区域一体化对非核心城市、欠发达城市、低财政分权城市具有更为显著的城市创新能力驱动作用。     

Water molecules bonded to the carboxylate groups at the inorganic–organic interface of an inorganic nanocrystal coated with alkanoate ligands

High-quality colloidal nanocrystals are commonly synthesized in hydrocarbon solvents with alkanoates as the most common organic ligand. Water molecules with an approximately equal number of surface alkanoate ligands are identified at the inorganic–organic interface for all types of colloidal nanocrystals studied, and investigated quantitatively using CdSe nanocrystals as the model system. Carboxylate ligands are coordinated to the surface metal ions and the first monolayer of water molecules is found to bond to the carboxylate groups of alkanoate ligands through hydrogen bonds. Additional monolayer(s) of water molecules can further be adsorbed through hydrogen bonds to the first monolayer of water molecules. The nearly ideal environment for hydrogen bonding at the inorganic–organic interface of alkanoate-coated nanocrystals helps to rapidly and stably enrich the interface-bonded water molecules, most of which are difficult to remove through vacuum treatment, thermal annealing and chemical drying. The water-enriched structure of the inorganic–organic interface of high-quality colloidal nanocrystals must be taken into account in order to understand the synthesis, processing and properties of these novel materials.     

Guazia,the earliest ovule without cupule but with unique integumentary lobes

The earliest ovules in the Late Devonian (Famennian) are surrounded by a cupule that is involved in both protection and pollination, and generally have free integumentary lobes. Here we report a new taxon from the Famennian of China, Guazia dongzhiensis gen. et sp. nov. The terminally borne ovule is apparently acupulate (without cupule) and has four radially arranged wing-like integumentary lobes that are extensively fused, and folded lengthwise and inwards. Guazia provides evidence that not all Devonian seeds possess a cupule and it increases their diversity in integumentary lobes. This genus also suggests that the integuments develop new functions, probably including wind dispersal at the expense of the cupules.     

网络舆论对伊朗突发新闻关注热点分析——以少将遇袭和导弹袭击事件中的微博为基础

本文探究网络舆论对伊朗突发新闻的关注热点,进而透过社交媒体分析网络舆论对国际热点事件的关注倾向.以含有关键词"伊朗少将遇袭"、"伊朗导弹袭击"和"伊朗"的所有微博作为研究数据,基于词频统计和LDA主题模型提取主题,从文本特征角度分析网络舆论对伊朗局势的关注热点.本研究对基于新浪微博数据检索到的文本内容进行分析发现,网络...     

批评在班级管理中的灵活应用

表扬与批评是班主任做好班级管理工作的重要手段。只有适度、适时、有效的表扬与批评,才能起到鼓励先进、鞭策后进的作用,达到既定的教育目标。因此,注重批评艺术,将各种消极因素消除在萌芽状态,显得尤为重要。一、批评的场合和时机一般来说,对于个别学生批评宜单独进行;对于那些一时不能正确认识自己的错误、比较固执的学生,可以适当在办公室进行批评,使其及时认识并改正自己的错误;对于自尊心很强又“爱面子”的学生,则应以单独聊天的方式进行批评,并创造一种轻松和谐的气氛,让其在与教师的平等交谈中认识自己的错误。只有批评一人可以教…