中引式气力输送系统的特性研究

中引式气力输送系统具有独立、串联和远近距离均适应的优点．通过实验研究,探讨了中引式气力输送系统的流动模式、管道阻力特性和输送压力频谱特性等．实验结果表明,中引式气力输送随着操作气速的变化,管内灰栓的流动模式也相应发生变化,分别为：柱塞流、栓流和悬浮流;柱塞流压力频谱较小,灰栓、气栓相间的多栓流属基本稳定流动;栓流压力频谱振幅最大,易成为独栓,属不稳定流动,输送量与柱塞流相当;悬浮流压力频谱最低,属稳定流动,输送量最低,输送速度最快,管道易磨损．柱塞流、栓流及悬浮流模式,对于给定物料操作气速与输送平均压力之间随着操作气速增加,输送压力逐渐下降．     

Information-governing dynamics of attacker–defender interactions in youth rugby union

Abstract

Previous work on dynamics of interpersonal interactions in 1 vs. 1 sub-phases of basketball has identified changes in interpersonal distance between an attacker and defender as a potential control parameter for influencing organizational states of attacker–defender dyads. Other studies have reported the constraining effect of relative velocity between an attacker and defender in 1 vs. 1 dyads. To evaluate the relationship between these candidate control parameters, we compared the impact of both interpersonal distance and relative velocity on the pattern-forming dynamics of attacker–defender dyads in the sport of rugby union. Results revealed that when interpersonal distance achieved a critical value of less than 4 m, and relative velocity values increased or were maintained above 1 m · s^?1, a successful outcome (i.e. clean attempt) for an attacker was predicted. Alternatively, when values of relative velocity suddenly decreased below this threshold, at the same critical value of interpersonal distance, a successful outcome for the defender was predicted. Data demonstrated how the coupling of these two potential, nested control parameters moved the dyadic system to phase transitions, characterized as a try or a tackle. Observations suggested that relative velocity increased its influence on the organization of attacker–defender dyads in rugby union over time as spatial proximity to the try line increased.     

固相萃取-气相色谱质谱法测定水中七氯

实验采用固相萃取-气相色谱质谱法对水样的七氯进行分析,优化前处理条件及气相色谱质谱条件,方法最低检测质量浓度可达0.00005mg/L,标准曲线的线性相关系数r2=0.998线性范围为0.0002～0.01mg/L,样品平均加标回收率在101.7%～112.4%之间,相对标准偏差在1.81%～5.15%。该方法操作简单、灵敏度高、准确、重现性好。     

1,1,1—三羟甲基烷烃的相转移催化合成

本文使用相转移催化剂（ＴＢＡＢ）合成了空间位阻大、碳链长的６个含特丁基的三羟甲基烷烃ｔ－Ｂｕ（ＣＨ２）ｎＣ（ＣＨ２ＯＨ）３（ｎ＝０、１、２、３、４、６），测定了这些化合物的熔点，进行了元素分析、质谱、红外光谱鉴定。     

Wet-chemical synthesis of two-dimensional metal nanomaterials for electrocatalysis

Two-dimensional (2D) metal nanomaterials have gained ever-growing research interest owing to their fascinating physicochemical properties and promising application, especially in the field of electrocatalysis. In this review, we briefly introduce the recent advances in wet-chemical synthesis of 2D metal nanomaterials. Subsequently, the catalytic performances of 2D metal nanomaterials in a variety of electrochemical reactions are illustrated. Finally, we summarize current challenges and highlight our perspectives on preparing high-performance 2D metal electrocatalysts.     

高温工作环境中FeCo基纳米晶合金的介观结构相

利用原子力显微镜和高分辨场发射电子显微镜系统地研究了高温退火的FeCo基纳米晶合金薄带的介观结构。发现高温退火的FeCo基纳米晶合金中具有纳米晶粒的团聚结构,尺寸约为200hm2由x射线衍射结果和目前已有的实验成果推断这种团聚结构中大约有104—105个纳米晶粒及包围这些纳米晶粒的非晶相。这种团聚结构与退火温度的高低具有十分密切的关系,因此称之为高温工作环境中FeCo基纳米晶合金的介观结构相,简称介观结构相。     

The role of pelvis-thorax coupling in controlling within-golf club swing speed

Pelvis-thorax coordination has been recognised to be associated with swing speed. Increasing angular separation between the pelvis and thorax has been thought to initiate the stretch shortening cycle and lead to increased clubhead speed. The purpose of this study was to determine whether pelvis-thorax coupling played a significant role in regulating clubhead speed, in a group of low-handicap golfers (mean handicap = 4.1). Sixteen participants played shots to target distances determined based on their typical 5- and 6-iron shot distances. Half the difference between median 5- and 6-iron distance for each participant was used to create three swing effort conditions: “minus”, “norm”, and “plus”. Ten shots were played under each swing effort condition using both the 5-iron and 6-iron, resulting in six shot categories and 60 shots per participant. No significant differences were found for X-factor for club or swing effort. X-factor stretch showed significant differences for club and swing effort. Continuous relative phase (CRP) results mainly showed evidence of the stretch shortening cycle in the downswing and that it was more pronounced late in the downswing as swing effort increased. Substantial inter-individual CRP variability demonstrated the need for individual analyses when investigating coordination in the golf swing.     

烃类水合物高压密相波形板壁防火材料设计

设计防火材料中,对防火特性基质的合成材料的设计研究是关键,烃类水合物在持续受热条件下具有较好的阻燃性能,烃类水合物是由碳和氢两种元素组成的有机化合物,是具有一定潜质的选材原料。为解决烃类水合物高压密相波形板壁隔热防火材料设计中关键技术问题,开展对烃类水合物高压密相波形板壁隔热防火材料设计的研究和实验工作,采用高压密相波形板壁设计方法,合成出Ui O-66(Zr)烃类水合物隔热防火材料。基于变压吸附分离技术,分析材料的热稳定性、化学稳定性、力学稳定性和热降解特性。利用烃类水合物高压密相波形板壁隔热技术实现对高热稳定和水稳定的隔热防火材料研究。实验得出,当样品升温速率低于加热系统的升温速率,样品受到外部加热的作用,发生破乳和水分挥发,实现阻止燃烧的功效,有效提高阻燃性能,采用该隔热防火材料,阻燃和耐高温性能较优越。     

相转移催化法合成十二烷基溴

采用液—液相转移催化法合成十二烷基溴，对影响反应的收率的各种因素进行研究，确定反应的最佳条件，收率达96％，氢溴酸消耗和反应时间与文献相比均减少一半．     

基于行为分阶段模型的我国毛南族居民健身行为与生命质量的再研究

有规律的健身行为是一种良好的健康促进行为之一,人类健康水平的提高是生理、心理和社会三方面处于完美状态。运用量表法、数理统计法等研究方法,以广西毛南族居民为研究对象,再次探讨在人类行为限制模型框架下探讨少数民族健身行为的发生、发展和与提高生命质量的关系。研究认为,位于健身不同阶段的居民拥有不同生命质量的得分,健身行为越有规律,健康水平越高,生命质量也越高;人类健身行为改变和相对较高生命质量的形成过程存在"第一阶段困境"和"第二阶段惰性"的障碍。