大型油船货油装卸仿真模拟装置的开发   总被引：1，自引：0，他引：1  

曾向明詹玉龙  张道兵 《上海海事大学学报》2006,27(1):5-8

运用计算机仿真技术和V isual C 软件设计工具,开发研制基于大型油船货油装卸系统的仿真模拟装置,以供教学与船员培训之用.探讨大型油船货油装卸仿真模拟装置的应用,介绍系统的结构以及软件的实现方法.  相似文献   

油画材料技法及其再认识     

吴东弓 《华侨大学学报(哲学社会科学版)》2001,(2):108-113

现代油画家与古代大师的显不同在于；古代大师对使用的材料工具了如指掌，而现代画家却知之甚少。本从理论上剖析油画材料的性能和特点，阐述了油画材料技法的原则及其关键问题－－光泽度、干燥速度、胶油混合技法，并指出现代油画材料技法运用所存在的新问题，对材料技法的再认识将有助于中国油画艺术的发展。  相似文献   

Reciprocal Versus Nonreciprocal Assessment of Knee Flexors and Extensors in Concentric Actions Using the CON-TREX Multijoint Isokinetic Dynamometer: A Reliability Study     

Alex Bliss  Jeanne Dekerle 《Measurement in physical education and exercise science》2019,23(2):118-123

Knee flexor and extensor muscular assessment via isokinetic dynamometry is common practice and established in the research literature. However, reporting assessment methodology regarding reciprocal and nonreciprocal movements is often vague or absent. Such methodological issues are crucial for accurate assessments. Therefore, knee extensor and flexor peak moment using either reciprocal movement or nonreciprocal modalities was assessed. Fifteen participants performed three blocks of five concentric muscle actions at three angular velocities [1: nonreciprocal (maximal active flexion followed by passive extension); B2: reciprocal (maximal active extension followed by maximal active flexion); B3 nonreciprocal (maximal active extension followed by passive flexion)]. ANOVA revealed statistically significant within-subject modality effects for peak knee extensor moment and flexor velocity and modality differences (p < .05). Reciprocal and nonreciprocal assessments give significantly different results, with nonreciprocal giving higher peak moments. Reporting which modality is used is crucial to allow for greater clarity for the reader and practitioner.  相似文献   

西非—中国航线原油远洋运输方案优化     

周晓玲  王震  肖文涛  许国栋 《上海海事大学学报》2017,38(1):31-36

为满足西非—中国航线的原油远洋运输方案的时效性要求,以油船运费、滞期费和靠港费之和最低为目标函数,以供需平衡、港口水深和装卸时间为约束条件,求解一个包含船型组合、装/卸港航线组合、油种替换、批次拆分等多决策变量的大规模NP(Non-deterministic Polynomial)难问题.采用差分进化算法进行求解.为提高求解速度,采用双染色体编码、基因组压缩编码、船型与拼装变量隐式联锁、配送油种比对解码等方法,进行供需平衡约束,降低问题规模,并缩减问题的"劣质解空间",提高差分进化算法的搜索时效.利用提出的算法对中国石化某月度西非—中国航线实际原油远洋运输方案进行优化,得到优化方案平均用时约5 min,可节约运费50余万美元.  相似文献   

Performing under pressure: Exploring the psychological state underlying clutch performance in sport     

Christian Swann  Lee Crust  Patricia Jackman  Stewart A. Vella  Mark S. Allen  Richard Keegan 《Journal of sports sciences》2017,35(23):2272-2280

Clutch performance is improved performance under pressure. However, little research has examined the psychological state experienced by athletes in these situations. Therefore, this study qualitatively examined the subjective experience underlying clutch performance across a range of sports (e.g., team, individual) and standards (Olympic to recreational athletes). Sixteen athletes (M_age = 27.08 years; SD = 6.48) took part in in-depth, semi-structured interviews primarily after an exceptional performance (M = 4.38 days later; SD = 3.14). Data were analysed inductively and thematically. Clutch states involved 12 characteristics, including heightened and deliberate concentration, intense effort, and heightened awareness, which distinguished the experience of clutch from other optimal psychological states such as flow. Other characteristics, such as perceptions of control, were also reported and supported previous experimental research on clutch. These findings present in-depth qualitative insights into the psychological state underlying clutch performance, and are discussed in relation to the existing literature on optimal psychological states in sport.  相似文献   

超高含水原油混合流动及初始沉积特性     

邢晓凯  吕朝旭  刘珈铨 《中国科学院大学学报》2020,37(2):228-233

使用自行设计的实验装置，对超高含水原油的流动特性和初始沉积过程进行探究。系统研究实验温度、混合流速和体积含水率对超高含水原油初始沉积过程的影响，分析不同温度下原油的运动形态和初始沉积方式。初始沉积过程可分为蔓延沉积过程和粘连沉积过程，根据沉积特点和压降曲线的变化趋势将初始沉积过程分为3个阶段：沉积诱导期、快速沉积期和沉积动态平衡期。通过对沉积物碳数分布的分析，得知超高含水原油初始沉积过程中，同时存在剪切剥离作用、胶凝作用和分子扩散作用。实验温度和体积含水率主要通过改变胶凝作用和分子扩散来影响初始沉积过程，混合流速通过改变剪切剥离强度来影响初始沉积过程。  相似文献   

船用双燃料发动机燃油系统仿真     

王源庆  任光  张均东 《上海海事大学学报》2016,37(1):87-91

为研究双燃料发动机燃油系统运行特性，以曼恩8L51/60DF双燃料发动机为研究对象，运用流体力学和插值算法，针对双燃料系统的三种工作模式（柴油模式、燃气模式、备用模式），建立柴油系统、燃气系统、引燃油系统综合数学模型.基于天然气的物理、化学性能与液体燃油不同，燃料油系统高压油泵凸轮模型对系统影响大等特点，对传统共轨柴油机模型中凸轮的弹性模量进行改进，以适应双燃料系统模型的建立.最后，利用MATLAB/Simulink对建立的系统模型进行数值计算，实现对柴油系统、燃气系统、引燃油系统的动态仿真和特性分析.仿真结果表明，系统模拟出的双燃料发动机燃油系统的运行特性与实际相符.该模型可应用于双燃料发动机控制系统的算法设计.  相似文献   

The cumulative and residual fatigue response associated with soccer-specific activity performed on different playing surfaces     

Richard Michael Page  Ben Langley  Mitchell James Finlay  Matt Greig  Christopher Brogden 《Journal of sports sciences》2020,38(5):568-575

ABSTRACT

This study aimed to assess the effect of playing surface (Natural [NT] and Artificial [AT] Turf) on the fatigue response to a soccer-specific exercise protocol (SSEP). Eighteen male soccer players completed the SSEP on NT and AT with pre-, post-, and 48 h post-assessments of eccentric knee flexor (eccKF) and concentric knee extensor peak torque (PT), peak countermovement (CMJ) and squat jump (SJ) height, and Nordic hamstring break angle. No significant main effects for surface or any surface and time interactions were observed for any of the outcome measures, except for eccKF PT recorded at 3.14 rad·s^-1, which was significantly lower 48 h post-trial in the AT condition (AT = 146.3 ± 20.4 Nm; NT = 158.8 ± 24.7 Nm). Main effects for time were observed between pre- and post-trial measures for eccKF PT at all angular velocities, Nordic break angle, CMJ and SJ height. Nordic break angle, and both CMJ and SJ height were significantly impaired 48 h post-trial when compared to pre-trial. The findings of the current study suggest surface dependent changes in eccKF PT which may have implications for recovery and subsequent performance after competition on AT.  相似文献   

Comparison of oil and egg tempera paint systems using time-of-flight secondary ion mass spectrometry     

Zachary E. Voras  Kristin deGhetaldi  Brian Baade  Eric Gordon  Glenn Gates  Thomas P. Beebe 《文物保护研究》2016,61(4):222-235

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is quickly becoming a critical tool in the field of art conservation. This technique provides high-resolution spatial maps of both inorganic and organic components located within cross-sectional samples collected from works of art. With recent advances in surface analysis, ToF-SIMS can now be used to identify specific amino acids present in protein-containing materials as well as fatty acids in drying oils. For example, the detection of the ion fragment associated with the amino acid hydroxyproline can be used to confirm the use of animal glue in a paint sample. As an analytical technique, ToF-SIMS avoids the need for derivatization/silylation reagents, with no interference by the presence of pigments. Furthermore, the layered systems that are often encountered in historical paint samples remain intact throughout the analytical procedure. This allows for the co-localization of organic and inorganic species in specific layers (e.g. egg yolk paint atop a glue ground). Because of this ability to localize the analytical signal to approximately 6?µm or less, the mass spectral information can be used to produce mass-resolved and spatially-resolve images which can be correlated to previous studies of the same samples. In this study, ToF-SIMS was used to analyze a paint cross section obtained from a painting attributed to Raphael, and another from a painting by the Sienese artist Matteo di Giovanni.  相似文献   

Effects of high-intensity interval training on cardiometabolic risk factors in overweight/obese women     

Abbie E. Smith-Ryan  Eric T. Trexler  Hailee L. Wingfield  Malia N.M. Blue 《Journal of sports sciences》2016,34(21):2038-2046

The purpose of this study was to evaluate two practical interval training protocols on cardiorespiratory fitness, lipids and body composition in overweight/obese women. Thirty women (mean ± SD; weight: 88.1 ± 15.9 kg; BMI: 32.0 ± 6.0 kg · m²) were randomly assigned to ten 1-min high-intensity intervals (90%VO₂ peak, 1 min recovery) or five 2-min high-intensity intervals (80–100% VO₂ peak, 1 min recovery) or control. Peak oxygen uptake (VO₂ peak), peak power output (PPO), body composition and fasting blood lipids were evaluated before and after 3 weeks of training, completed 3 days per week. Results from ANCOVA analyses demonstrated no significant training group differences for any primary variables (P > 0.05). When training groups were collapsed, 1MIN and 2MIN resulted in a significant increase in PPO (?18.9 ± 8.5 watts; P = 0.014) and time to exhaustion (?55.1 ± 16.4 s; P = 0.001); non-significant increase in VO₂ peak (?2.36 ± 1.34 ml · kg^?1 · min^?1; P = 0.185); and a significant decrease in fat mass (FM) (??1.96 ± 0.99 kg; P = 0.011). Short-term interval exercise training may be effective for decreasing FM and improving exercise tolerance in overweight and obese women.  相似文献