NiCo_2O_4纳米结构阵列的水热合成与氧析出特性研究

钴酸镍纳米材料具有良好的电催化氧析出反应(Oxygen Evolution Reaction,OER)活性,是一种很有发展潜力的非贵金属电催化材料。文章以碳纤维纸为基底,采用水热合成的方法对纳米结构钴酸镍的生长进行了系统的研究,分别考察了生长温度、前驱体浓度和配比、生长时间对产物的形貌、尺寸、物相结构、OER电化学性能的影响,通过对比分析后发现在生长温度100℃、生长时间5h、镍钴比为2:1时所获得的多孔片状钴酸镍纳米结构具有最佳的OER特性。     

Evaluation of adverse drug reaction formatting in drug information mobile phone applications

Objective:To evaluate the differences in presentation (formatting) of adverse drug reaction (ADR) information within drug monographs in commonly used drug information (DI) mobile device applications.Methods:A cross-sectional analysis of ADR formatting of twenty commonly prescribed oral medications within seven DI mobile applications was performed. Databases were assessed for ADR information, including presence of placebo comparisons, severity of ADR, onset of ADR, formatting of ADRs in percentile (quantitative) format or qualitative format, whether references were used to cite information, and whether ADRs are grouped by organ system. Data was collected by two study investigators and discrepancies were resolved via consensus.Results:The seven DI mobile applications varied significantly on every analyzed ADR variable with the exception of ADR onset, which was absent in all databases. Significant differences were found for variables known to impact clinical judgment such as placebo comparisons and qualitative versus quantitative formatting. Placebo comparisons were most common among monographs in Lexicomp (30%) but were absent among monographs within other applications. Quantitative information was commonly used in most databases but was absent in Epocrates. Qualitative formatting was present in all Epocrates and Micromedex applications but absent in the majority of other applications. Substantial variations were also found in severity and grouping information.Conclusion:Substantial variation in ADR formatting exists among the most common DI mobile applications. These differences may translate into alternative interpretations of medical information and thus impact clinical judgment. Health care librarians and clinicians should consider ADR formatting when choosing between DI applications.     

环庚三烯酮与邻二甲氧基苯在浓硫酸作用下的缩合重排反应机理

环庚三烯酮易发生环加成反应,偶尔有烯烃键上的取代反应.关于二甲氧基苯,多年来的主要关注点是其与不同醛或酮在强酸作用下的缩合反应,但多局限在芳基醛或饱和脂肪醛酮.本研究尝试多共轭不饱和酮与邻二甲氧基苯的缩合反应.结果发现在浓硫酸作用下环庚三烯酮不仅可以发生脱水缩合反应,更有趣的是环庚三烯酮在强酸及二甲氧基苯协同作用下可以发生重排缩环反应,由七元环收缩成六元芳香环.     

2008-2009年全国女排联赛运动员非技术性指标研究

采用文献资料法、数理统计法等,对2008年奥运会前8名球队女排队员与中国俱乐部女排队员的年龄、身高、扣球高度和拦网高度等非技术性指标进行研究,结果显示：俱乐部女排队员的平均身高和扣球高度已达到世界强队的平均水平,拦网高度明显高于世界强队平均水平,队员比较年轻,结构合理,克托莱指数明显低于世界强队的平均水平。各俱乐部之间队员的非技术性指标也存在差异。     

我国优秀女排队员移动拦网技术动作解析

1前言近年来世界排球大赛的实践表明，拦网已从单一的防守技术转变为攻防兼备的制胜技术之一。拦网水平的高低不仅直接影响比赛的胜负，而且也是衡量一支球队技战术水平的重要标志之一，因此，备受国内外教练员和科研工作者的关注。长期以来，有关拦网技术的研究，仅限于现场统     

Kinematic and kinetic analysis of overhand,sidearm and underhand lacrosse shot techniques

Lacrosse requires the coordinated performance of many complex skills. One of these skills is shooting on the opponents’ net using one of three techniques: overhand, sidearm or underhand. The purpose of this study was to (i) determine which technique generated the highest ball velocity and greatest shot accuracy and (ii) identify kinematic and kinetic variables that contribute to a high velocity and high accuracy shot. Twelve elite male lacrosse players participated in this study. Kinematic data were sampled at 250 Hz, while two-dimensional force plates collected ground reaction force data (1000 Hz). Statistical analysis showed significantly greater ball velocity for the sidearm technique than overhand (P < 0.001) and underhand (P < 0.001) techniques. No statistical difference was found for shot accuracy (P > 0.05). Kinematic and kinetic variables were not significantly correlated to shot accuracy or velocity across all shot types; however, when analysed independently, the lead foot horizontal impulse showed a negative correlation with underhand ball velocity (P = 0.042). This study identifies the technique with the highest ball velocity, defines kinematic and kinetic predictors related to ball velocity and provides information to coaches and athletes concerned with improving lacrosse shot performance.     

Predicting ground reaction forces in running using micro-sensors and neural networks

Measurement of ground reaction force (GRF) in running provides a direct indication of the loads to which the body is subjected at each foot-ground contact, and can provide an objective explanation for performance outcomes. Traditionally, the collection of three orthogonal component GRF data in running requires an athlete to complete a series of return loops along a laboratory based runway, within which a force platform is embedded, in order to collect data from a discrete footfall. The major disadvantages associated with this GRF data collection methodology include the inability to assess multiple consecutive foot contacts and the fact that measurements are typically confined to the laboratory. The objective of this research was to investigate the potential for wearable instrumentation to be employed, in conjunction with artificial neural network (ANN) and multiple linear regression (MLR) models, for the estimation of GRF in middle distance running. A modular wearable data acquisition system was developed to acquire in-shoe force (ISF) data. Matched data sets from wearable instrumentation (source data) and force plate (target data) records were collected from elite middle-distance runners under controlled laboratory conditions for the purposes of ANN and MLR model development (MD) and model validation (MV). In terms of statistical measures of prediction accuracy the MLR model was found to provide a superior level of accuracy for the prediction of the vertical and medio-lateral components of GRF and alternatively, the ANN model provided the most accurate predictions of the anterior-posterior component of GRF. The prediction accuracy of each component of GRF was found to be governed by the inherent signal variability, in which case the vertical and anterior-posterior components were more reliable and subsequently predicted significantly more accurately than the medio-lateral component. The emerging capability for obtaining continuous GRF records from wearable instrumentation has the potential to permit unprecedented quantification of training stress and competition demands in running.     

羽毛球运动员的反应时与竞技能力

反应时是研究运动员心理特征的重要指标,然而以往研究结果并不一致。通过采用自编程序的微机视觉反应时测验,以不同反应时与竞技能力的相关差异,探讨影响竞技能力的神经机制。反应时测试有简单反应时、复杂反应时二刺激、辨别反应时二刺激、复杂反应时四刺激和翻转反应时四刺激。46名男队员和61名女队员按成绩分成优秀和一般两组,结果发现:简单反应时复杂反应四刺激和翻转反应四刺激指标在不同水平男女运动员中均表现出显著性差异,而简单反应时不显著。翻转反应时在不同水平羽毛球运动员之间差异效果量为最大。结果提示:羽毛球运动员的竞技能力不仅与信息加工速度有关,还与信息复杂程度有关,优秀羽毛球运动员加工复杂信息更具优势,灵活的神经转换机制可能是影响羽毛球运动员竞技能力的中央机制之一。     

太极拳运动单脚支撑姿势持续时间与地面反作用力特征的分析

运用摄影测量法和Novel Pedar-X足底压力测试系统采集了16名太极拳练习者在太极拳运动和正常步行中足底压力和运动影像信息,并对两种运动方式的单脚支撑姿势持续时间指标进行对比分析。研究表明:与正常步行相比,在太极拳运动中单脚支撑姿势总的持续时间所占比例(标准化值)较少(P<0.05);单次单脚支撑姿势平均持续时间较长(P<0.01);认为太极拳运动可以提高人体单脚平衡能力。另外还发现太极拳运动和正常步行中地面反作用力都在不断变化;太极拳运动中地面反作用力小于其正常步行值。     

一类反应扩散方程新的行波解

介绍了一种求解非线性偏微分方程行波解的方法——双函数法,利用该方法求得一类反应扩散方程在不同情况下的新的行波解,Chaffee-Infane方程和Huxley方程作为这一类反应扩散方程的特例也得到了相应的行波解。该方法还可推广到高维非线性反应扩散方程(组)进行求解。