Study on the nature of pressure signals in a bubbling fluidized bed

In this study on the nature of pressure signals generated by a deterministic or stochastic process in a bubbling fluidized bed, pressure fluctuation measurements were carried out in a 300-mm-diamet column at 0.090 m and 0.40 m above the distributor for different gas velocities. The method of detecting deterministic dynamic underlying pressure signals is proposed on the basis of predictability of pressure fluctuations. The deterministic nature of dynamics in fluidizing system was verified. The deterministic level of dynamics in fluidizing system was analyzed for different locations of pressure measurements and different gas velocities. Project supported by the Science and Engineering Foundation of SINOPEC, China (X599029)     

150例高血压病患者并发症临床观察

目的:探讨单纯收缩期高血压、收缩压与舒张压高血压并发心脑血管病的机率。方法:将150例高血压患者分成3组:52例舒张压升高患者;15例单纯收缩期高血压;54例收缩期、舒张期均高的高血压并发心脑血管病发症的患者进行临床分析。结果:单纯舒张期高血压预后良好,而单纯收缩期高血压及收缩压合并舒张压升高者有较大的发生心脑血管病的危险性。结论:对单纯收缩期高血压、及收缩压合并舒张压升高的患者应给予足够重视,并积极治疗。     

Kinematics and kinetics of the drive off the front foot in cricket batting

A cinematographic analysis of the drive off the front foot (D) and the forward defensive stroke (FD) was undertaken to establish the kinematic and kinetic factors involved in playing these strokes against medium-fast bowling. Fourteen provincial cricket batsmen were filmed at 100 Hz while batting on a turf pitch with a specially instrumented bat. Results for the drive off the front foot revealed that the movement and stroke pattern were generally supportive of the coaching literature, with the forward defensive stroke forming the basis of the drive. Certain mechanical differences, although non-significant, were evident to facilitate the attacking nature of the front foot drive and included a higher backlift (FD = 0.65 m; D = 0.74 m), later commencement of the stride (FD = 0.64 s pre-impact; D = 0.58 s pre-impact) and downswing of the bat (FD = 0.38 s pre-impact; D = 0.36 s pre-impact), a shorter front foot stride (FD = 0.72 m; D = 0.68 m) with the front foot placement taking place later (FD = 0.14 s pre-impact; D = 0.06 s pre-impact), and the back foot dragging further forward at impact (FD = 0.05 m; D = 0.10 m). The front upper limb moved as a multi-segmental series of levers, which resulted in the drive showing significantly greater (P < 0.05) peak bat horizontal velocity at 0.02 s preimpact (FD = 3.53 ± 3.44 m . s -1 ; D = 11.8 ± 4.61 m . s -1 ) and 0.02 s post-impact (FD = 2.73 ± 2.88 m . s -1 ; D = 11.3 ± 4.21 m . s -1 ). The drive showed a significantly greater (P < 0.05) bat-ball closing horizontal velocity (FD = 24.2 ± 4.65 m . s-1; D = 32.3 ± 5.06 m . s -1 ) and post-impact ball horizontal velocity (FD = 6.85 5.12 m . s -1 ; D = 19.5 ± 2.13 m . s -1 ) than for the forward defensive stroke. The point of bat-ball contact showed nonsignificant differences, but occurred further behind the front ankle (FD = 0.09 ± 0.17 m; D = 0.20 ± 0.13 m), with the bat more vertical at impact (FD = 62.6 ± 6.53 ; D = 77.8 ± 7.05). Significant differences (P < 0.01) occurred between the grip forces of the top and bottom hands for the two strokes, with the principal kinetic finding that the top hand plays the dominant role during the execution of the drive with the bottom hand reinforcing it at impact. Similar grip force patterns for the two strokes occurred during the initial part of the stroke, with the drive recording significantly greater (P < 0.05) forces at 0.02 s pre-impact (top hand: FD = 129 ± 41.6 N; D = 199 ± 40.9 N; bottom hand: FD = 52.2 ± 16.9 N; D = 91.8 ± 41.1 N), at impact (top hand: FD = 124 ± 29.3 N; D = 158 ± 56.2 N; bottom hand: FD = 67.1 ± 21.5 N; D = 86.2 ± 58.2 N) and 0.02 s postimpact (top hand: FD = 111 ± 22.2 N; D = 126 ± 28.5 N; bottom hand: FD = 65.5 ± 26.9 N; D = 82.4 ± 28.6 N).     

高职院校女教师的心理压力及对策研究

由于社会的多重要求与自身的多重角色,对高职女教师提出了严峻挑战,使她们的心理压力日趋增大,影响了女教师的身心健康和事业发展。因此女教师只有培养乐观积极的心态,逐渐释放压力,超越自我,才能更好适应飞速发展的高职教育。     

Nonlinear dynamic analysis of the Three Gorge Project powerhouse excited by pressure fluctuation

This study established a 3D finite element model for 15# hydropower house of the Three Gorges Project （TGP） and performed a nonlinear dynamic analysis under pressure fluctuation. In this numerical model, the stiffness degradation in tension for concrete was considered on the basis of the continuum isotropic damage theory. Natural vibration frequencies of the damaged and undamaged structures were compared after static water pressure was applied. Then a study was further conducted on forced vibration of the powerhouse with pre-existing damages under pressure fluctuation that acts on the flow passage; displacement, velocity and acceleration of the important structural members were afterwards presented and checked. Numerical results show that tensile damages in concrete surrounding the spiral case only exert significant impact upon the dynamic characteristics of substructure but show little effect on the superstructure. Nevertheless vibrations of the powerhouse are still under the recommended vibration limits.     

旧住宅水压不稳定原因简析及改造方案

通过对某住宅生活给水水压不稳定原因进行分析，并参考《建筑给水排水设计规范GB50015—2003》及建筑给水排水工程相关知识，提出了解决方法，分析了水压不稳的原因，折射当前旧住宅给水设计存在的普遍问题。     

Pressure from the lips and the tongue in children with class III malocclusion

Objective:To discuss possible relationships between class III malocclusion and perioral forces by measuring the pressure from the lips and the tongue of children with class III malocclusion. Methods:Thirty-one children with class III malocclusion were investigated and their perioral forces were measured at rest and during swallowing under natural head position by a custom-made miniperioral force computer measuring system. Results:The resting pressures exerted on the labial side and palatine side of the upper left incisor, as well as the labial side and lingual side of the lower left incisor, were 0 g/cm2, 0 g/cm2, 0.57 g/cm2 and 0.23 g/cm2, respectively. Correspondingly, the swallowing forces were 2.87 g/cm2, 5.97 g/cm2, 4.09 g/cm2 and 7.89 g/cm2, respectively. No statistical difference between muscular pressure and gender existed. During swallowing, the lingual forces were significantly higher than the labial forces (P<0.01), however, at rest there was no significantly different force between these two sides. Compared to the normal occlusion patients, children with class III malocclusion had lower perioral forces. The upper labial resting forces (P<0.01), the lower labial resting forces (P<0.05) and all the swallowing pressures from the lips and the tongue (P<0.01) showed statistical differences between the two different occlusion conditions. Meanwhile, no significant difference was found for the resting pressure from the tongue between class III malocclusion and normal occlusion. Conclusion:Patients with class III malocclusion have lower perioral forces and this muscle hypofunction may be secondary to the spatial relations of the jaws. The findings support the spatial matrix hypothesis.     

球腔式压力脉动衰减器的设计分析

液压泵压力脉动影响系统工作性能，除改进液压泵设计之外，可在泵源装置中采用球腔式压力脉动衰减装置。     

浅析箱型重力式挡土墙的应用

文章探讨了采用箱型重力式挡土墙处理15m～20m高挡土墙的问题,克服了传统挡土墙应用的局限性,利用挡土墙箱内的填土来平衡外部土体压力,既减小了结构构件的截面尺寸又相应增加了重力式挡土墙的适用高度。     

基于ANSYS的流化床反应器结构强度分析

蔗渣流化床反应器是一种典型的压力容器,属于危险机械设备之一。针对其安全性要求,应用有限元软件AN-SYS并采用参数化命令流方式建立仿真分析模型及不同方法对蔗渣流化床反应器进行结构强度分析,对分析结果进行评价,最终找到该结构的薄弱环节,可为以后同类设备的设计改进提供参考依据。