析出硬化粉末冶金不锈钢

高硬度不锈钢的使用需求在快速增长.尽管析出硬化不锈钢具有高强度,但在粉末冶金(PM)中使用的并不多.可通过加入在时效过程形成金属问沉淀的成份如铜、铌对这些合金进行强化.析出硬化级不锈钢的耐腐蚀性能可与铬镍级(300系列)相媲美.本文提出了两种析出硬化不锈钢粉末的物理性质和微观结构:17-4PH,一种高铬马氏体析出硬化不锈钢,优化条件后应用于粉末冶金中;另一种是在析出反应中使用铜的新型低铬(12w/o)合金.这种新型合金(410LCu)被视为满足高强度和中等耐腐蚀性的要求的低成本选择.     

Electrokinetic focusing and filtration of cells in a serpentine microchannel

Focusing cells into a single stream is usually a necessary step prior to counting and separating them in microfluidic devices such as flow cytometers and cell sorters. This work presents a sheathless electrokinetic focusing of yeast cells in a planar serpentine microchannel using dc-biased ac electric fields. The concurrent pumping and focusing of yeast cells arise from the dc electrokinetic transport and the turn-induced ac∕dc dielectrophoretic motion, respectively. The effects of electric field (including ac to dc field ratio and ac field frequency) and concentration (including buffer concentration and cell concentration) on the cell focusing performance were studied experimentally and numerically. A continuous electrokinetic filtration of E. coli cells from yeast cells was also demonstrated via their differential electrokinetic focusing in a serpentine microchannel.     

The teaching well: Experience, education, and counselling

Wellness classes based on Eastern and Western philosophical concepts were offered to graduate level counselling students as a means of helping them to integrate and clarify their views on counselling. Through experiential activities, students learned to more fully activate inner creative resources for an enhanced sense of wholeness. The concepts and methods learned have practical application to counselling.     

Effects of antisocial behaviour on opponent's anger,attention, and performance

Sledging, which is verbal antisocial behaviour in sport, aims to impair an opponent’s performance. Previously, variations in performance have been attributed to changes in emotion and cognition. To improve our understanding of sledging, the current experiment examined the effects of verbal antisocial behaviour on anger, attention and performance. Participants performed a competitive basketball free-throw shooting task under insult (verbal behaviour designed to offend and upset the performer), distraction (verbal behaviour designed to draw attention away from the task), or control (neutral verbal behaviour) conditions. Performance was assessed by the number of successful baskets and a points-based scoring system, while anger and attention were measured post-task. The insult condition provoked more anger than the control and distraction conditions, whereas the insult and distraction conditions increased distraction and reduced self-focus compared to the control condition. Although verbal antisocial behaviour had no overall direct effect on performance, mediation analysis showed that anger indirectly impaired performance via distraction. Implications for the antisocial behaviour-performance relationship are discussed.     

An Investigation Into Handedness and Choking Under Pressure in Sport

When athletes fail to perform at an expected level during an important moment, it is implied the athletes have experienced “choking“ (sudden decline in performance) under pressure.”. Researchers have reported that persistent left-hemispheric activation patterns occur when an athlete experiences considerable performance deteriorations under pressure. Researchers have also observed differences in brain activation patterns between left- and right-handed people on a variety of physical and cognitive tests, with the left-hemispheric activation more pronounced in right-handed participants. Purpose: The purpose of this study was to investigate whether athletes’ handedness may be linked to choking susceptibility (i.e., likelihood to experience performance decline under pressure). Method: Twenty right-handed and 13 left-handed experienced Australian football players completed 15 shot attempts, in both a low-pressure and a high-pressure condition. Both groups displayed equal state anxiety increases due to the pressure manipulation, indicating similar increases in anxiety in both handedness groups. Results: Differences were indicated in performance between the left- and right-handed groups during the high-pressure condition, with the left-handed group maintaining, and the right-handed participants declining, performance. Conclusion: Future electroencephalogram (EEG) research investigating this link may clarify the effect between handedness and choking.     

Elite cricket coach education: a Bourdieusian analysis

The social structures within coach education have been largely unexplored, undiscussed, and treated as unproblematic in contributing to coach learning, both in research and practice. The study used semi-structured, in-depth interviews with 11 elite cricket coaches to gather their perceptions of an elite coach education programme. In particular, this research attempted a more nuanced critical inquiry into the impact of culture on coach learning, habitus on knowledge production and the extent to which capital structures practice within the field of cricket coach education. Data analysis followed abductive reasoning, combining inductive thematic analyses of the data, with a deductive abstraction of these themes within a Bourdieusian framework to provide a level of explanation to the data. The findings present coach education as a complex social field in which coaches were active social beings in the (re)production of coaching knowledge. The culture of cricket was found to perpetuate a powerful doxic system that highlighted the tensions and conflict between an accepted model of coach education with a singular and prescribed body of knowledge and a strong underlying sporting culture and individuals hierarchically placed within it. This data further highlighted how coach education contributes to the (re)production of power within the field of cricket coaching.     

Force– and power–time curve comparison during jumping between strength-matched male and female basketball players

The purpose of this study was to compare force– and power–time curve variables during jumping between Division I strength-matched male and female basketball athletes. Males (n?=?8) and females (n?=?8) were strength matched by testing a one-repetition maximum (1RM) back squat. 1RM back squat values were normalised to body mass in order to demonstrate that strength differences were a function of body mass alone. Subjects performed three countermovement jumps (CMJ) at maximal effort. Absolute and relative force– and power–time curve variables from the CMJs were analysed between males and females. Average force– and power–time curves were generated for all subjects. Jump height was significantly greater (p?≤?.05) in males than females. Absolute force was higher in males during the concentric phase, but not significantly different (p?≥?.05) when normalised to body mass. Significance was found in absolute concentric impulse between sexes, but not when analysed relative to body mass. Rate of force development, rate of power development, relative peak force, and work were not significantly different between sexes. Males had significantly greater impulse during the eccentric phase as well as peak power (PP) during the concentric phase of the CMJ than did females in both absolute and relative terms. It is concluded that sex differences are not a determining factor in measured force during a CMJ when normalised to body mass between strength-matched subjects. However, eccentric phase impulse and concentric phase PP appear to be influenced by sex differences independent of matching strength levels.     

The organisational stressors encountered by athletes with a disability

Organisational stressors have been found to be prevalent and problematic for sport performers, with research identifying demographic differences in the stressors encountered. Nevertheless, extant sport psychology research on the topic of stress has generally focused on able-bodied athletes; whilst that which has been conducted on performers with a disability has typically recruited relatively small samples to explore a narrow selection of organisational stressors, or examined other components of the stress process. The purpose of the present study was to explore the various organisational stressors that athletes with a disability encounter. The sample comprised 18 elite athletes with a disability (10 male, 8 female) who had a classified disability and experience of competing at a major championships in their sport (e.g., Paralympic Games, World Championships). Participants took part in a semi-structured interview which was analysed by drawing from grounded theory procedures. A total of 316 organisational stressors were identified, which were abstracted into 31 concepts and four, previously conceptualised, exploratory schemes: leadership and personnel issues, cultural and team issues, logistical and environmental issues, and performance and personal issues. This study not only provides the first illustration of the prevalence of organisational stressors for athletes with a disability, but also significantly points to salient similarities and distinct differences between the stress experiences of performers with and without a disability.