磁约束核聚变环境中流道插件的热变形分析

对国际热核聚变实验堆的双冷锂铅包层进行流固共轭传热的三维数值模拟,计算两端不同约束下流道插件FCI结构的热变形和热应力分布,分析对流换热系数和热导率对FCI结构热变形和热应力的影响规律.结果表明,若钢壁与外界的对流换热系数增大,则FCI温度降低,导致热变形和热应力减小;高热导率的FCI材料将使得FCI沿厚度方向温度梯度减小,导致结构的热应力减小.     

Effect of 6-weeks WBVT on the behaviour of the lower limb muscle fibres during vertical jumping

The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EG_WBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg^?1; P = 0.001), take-off velocity (0.1 cm · s^?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EG_WBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EG_WBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.     

对优秀自由式滑雪空中技巧运动员反应时与背力的研究

研究目的：自由式滑雪空中技巧运动属技能类难美项群的一个典型项目,对反应速度和肌肉力量都有很高的要求。通过对我国优秀自由式滑雪空中技巧运动员的反应时和背力的测量,并与体育学院大学生的进行对比,了解运动员的身体形态和机能特点,为今后我国优秀自由式滑雪空中技巧运动员的训练和选材提供一些参考。研究方法：以中国自由式滑雪空中技巧国家队的运动员16人作为研究组,体育学院04级社体大学生25人作为对照组,测量两组研究对象反应时和背力指标。研究结果：与对照组相比,运动员的背力较好,有统计学意义（P〈0.05）,反应时无统计学意义,但有存在差异的趋势;健将级运动员的背力和反应时与一般运动员相比,并无明显差异。研究结论：我国国家队的运动员已经拥有较好的背力,说明运动员在训练中已经加强了背力的训练;但反应时不理想,在今后的训练中有必要对此方面注意。     

影响篮球裁判员预判能力的因素分析

篮球裁判员预判能力好坏,对比赛能否顺利进行具有重要的意义。利用文献资料法从运动生理学、心理学角度出发,分析影响篮球裁判员预判能力的因素。通过对诸多因素分析,提出一些相关的具体训练方法,旨在提高篮球裁判员执裁水平。     

ISSR markers based on GA and AG repeats reveal genetic relationship among rice varieties tolerant to drought, flood, or salinity

Drought,flood,salinity,or a combination of these limits rice production.Several rice varieties are well known for their tolerance to specific abiotic stresses.We determined genetic relationship among 12 rice varieties including 9 tolerant to drought,flood,or salinity using inter-simple sequence repeat (ISSR) markers.Based on all markers,the nine tolerant varieties formed one cluster distinct from the cluster of three control varieties.The salt-tolerant varieties were closest to two flood-tolerant varieties,and together they were distinct from the drought-tolerant varieties.(GA)8 YG was the most informative primer,showing the highest polymorphic information content (PIC) and resolving power (Rp).The drought-,flood-,and salt-tolerant varieties grouped in three distinct clusters within the group of tolerant varieties,when (GA)8 YG was used.Sabita was the only exception.The two aus varieties,Nagina22 and FR13A,were separated and grouped with the drought-and flood-tolerant varieties,respectively,but they were together in dendrograms based on other primers.The results show that ISSR markers associated with (GA)8 YG delineated the three groups of stress-tolerant varieties from each other and can be used to identify genes/new alleles associated with the three abiotic stresses in rice germplasm.     

耐镉根瘤菌的筛选

采用液体培养基摇床培养根瘤菌,研究了Cd处理对根瘤菌生长的影响.依时间进程测定培养液在600nm吸光度并绘制根瘤菌生长曲线.筛选到一株耐Cd根瘤菌菌株X.5和10 μmol/L Cd处理48h对苜蓿根瘤菌标准菌株USDA生长抑制率分别为38%和58%,而此浓度Cd处理对X菌株生长具有一定的促进作用.BTB反应鉴定结果表明,菌株USDA和X均为快生型根瘤菌.     

坑道操对坑道作业人员反应时昼夜节律及调整的研究

以现代时间生物学理论为指导,应用单个余弦法进行生物节律分析和数据统计,观察在坑道环境中,正常作息制和光暗倒相制下坑道作业人员反应时的昼夜节律相位情况,以及坑道操对反应时节律的相位影响特点及规律。结果表明在正常作息制条件下,反应时表现明显的昼夜节律（P〈0.05）。在光暗倒相状态下,坑道操组表现明显的昼夜节律（P〈0.05）,而对照组不具有明显的昼夜节律。坑道操对反应时具有明显的调节作用。     

Independence of reaction time and response force control during isometric leg extension

In this study, we examined the relative control of reaction time and force in responses of the lower limb. Fourteen female participants (age 21.2±1.0 years, height 1.62±0.05?m, body mass 54.1±6.1?kg; mean±s) were instructed to exert their maximal isometric one-leg extension force as quickly as possible in response to an auditory stimulus presented after one of 13 foreperiod durations, ranging from 0.5 to 10.0?s. In the ‘irregular condition’ each foreperiod was presented in random order, while in the ‘regular condition’ each foreperiod was repeated consecutively. A significant interactive effect of foreperiod duration and regularity on reaction time was observed (P?<?0.001 in two-way ANOVA with repeated measures). In the irregular condition the shorter foreperiod induced a longer reaction time, while in the regular condition the shorter foreperiod induced a shorter reaction time. Peak amplitude of isometric force was affected only by the regularity of foreperiod and there was a significant variation of changes in peak force across participants; nine participants were shown to significantly increase peak force for the regular condition (P?<?0.001), three to decrease it (P?<?0.05) and two showed no difference. These results indicate the independence of reaction time and response force control in the lower limb motor system. Variation of changes in peak force across participants may be due to the different attention to the bipolar nature of the task requirements such as maximal force and maximal speed.     

Cardiopulmonary loading in motocross riding

Abstract

The present study was designed to examine physiological responses during motocross riding. Nine Finnish A-level motocross riders performed a 15-min ride at a motocross track and a test of maximal oxygen uptake ([Vdot]O_2max) in the laboratory. Cardiopulmonary strain was measured continuously during the ride as well as in the [Vdot]O_2max test. During the ride, mean [Vdot]O₂ was 32 ml · kg^?1 · min^?1 (s = 4), which was 71% (s = 12) of maximum, while ventilation (V _E) was 73% (s = 15) of its maximum. The relative [Vdot]O₂ and V _E values during the riding correlated with successful riding performance (r = 0.80, P < 0.01 and r = 0.79, P < 0.01, respectively). Mean heart rate was maintained at 95% (s = 7) of its maximum. Mean blood lactate concentration was 5.0 mmol · l^?1 (s = 2.0) after the ride. A reduction of 16% (P < 0.001) in maximal isometric handgrip force was observed. In conclusion, motocross causes riders great physical stress. Both aerobic and anaerobic metabolism is required for the isometric and dynamic muscle actions experienced during a ride.     

Effect of target change during the simple attack in fencing

Abstract

The aim of this study was to test the effect that changing targets during a simple long lunge attack in fencing exerts on the temporal parameters of the reaction response, the execution speed, and the precision and the coordination of the movement pattern. Thirty fencers with more than 10 years of experience participated in this study. Two force platforms were used to record the horizontal components of the reaction forces and thereby to determine the beginning of the movement. A three-dimensional (3D) system recorded the spatial positions of the 9 markers situated on the fencer plus the epee, while a moving target was projected on a screen, enabling the control of the target change. The results indicated that when a target change is provoked the reaction time (RT), movement time (MT), and the time used in the acceleration phase of the centre of mass (CM) increases significantly with respect to the attack executed with a straight thrust. The speed and horizontal distance reached by the CM at the end of the acceleration phase (V_X(CM) and S_X(CM), respectively) significantly decreased, while the errors increased. However, the temporal sequence of the movement pattern did not appreciably change.