推广的Redlich-Kwong实际气体绝热过程

根据热力学的基本理论,导出推广的Redlich-Kwong实际气体准静态绝热过程方程的微分形式,并分别对理想气体、VDW气体、Dieterici气体及RK气体准静态绝热过程作了详细的讨论.结果表明：实际气体准静态绝热过程在给定体积下的温度值略低于理想气体,从而提供了判断实际气体与理想气体准静态绝热过程的简单方法.     

The effect of pre-exercise carbohydrate feedings on the intensity that elicits maximal fat oxidation

The aim of the present study was to examine the effect of ingesting 75?g of glucose 45?min before the start of a graded exercise test to exhaustion on the determination of the intensity that elicits maximal fat oxidation (Fat_max). Eleven moderately trained individuals ( V?O_2max: 58.9±1.0?ml?·?kg^?1?·?min^?1; mean±s_x¯ ), who had fasted overnight, performed two graded exercise tests to exhaustion, one 45?min after ingesting a placebo drink and one 45?min after ingesting 75?g of carbohydrate in the form of glucose. The tests started at 95?W and the workload was increased by 35?W every 3?min. Gas exchange measures and heart rate were recorded throughout exercise. Fat oxidation rates were calculated using stoichiometric equations. Blood samples were collected at rest and at the end of each stage of the test. Maximal fat oxidation rates decreased from 0.46±0.06 to 0.33±0.06?g?·?min^?1 when carbohydrate was ingested before the start of exercise (P?<0.01). There was also a decrease in the intensity which elicited maximal fat oxidation (60.1±1.9% vs 52.0±3.4% V?O_2max) after carbohydrate ingestion (P?<0.05). Maximal power output was higher in the carbohydrate than in the placebo trial (346±12 vs 332±12?W) (P?<0.05). In conclusion, the ingestion of 75?g of carbohydrate 45?min before the onset of exercise decreased Fat_max by 14%, while the maximal rate of fat oxidation decreased by 28%.     

Morphology of polyethylene ski base materials

Abstract

We used high-resolution Raman spectroscopy and differential scanning calorimetry for a comprehensive analysis of carbon black-filled polyethylene ski base grades at processing stages from the raw material to the structured ski base. Based on Raman mapping, we assessed the applicability of an advanced evaluation procedure for amorphous, disordered, and crystalline phase fractions of polyethylene for polyethylene extrusion and sinter grades. For sinter grades, a sufficient segregation between carbon black and polyethylene was confirmed, allowing for a comprehensive Raman spectroscopic morphological analysis. Significant morphological changes in polyethylene due to processing from the raw material to the semi-finished film and to the structured ski base were identified. Throughout the processing chain, we observed a decrease in crystallinity and an increase in the amorphous phase fraction. Although the raw material and the sintered semi-finished film exhibited a different but uniform polyethylene morphology, the morphological changes due to structuring of the ski base are limited to the top surface layer. The highest amorphous phase fractions were detected in the surface of the structured ski bases.     

激光诱导原子布居数转移的探讨

在介绍非相干布居数转移和相干布居数转移技术及相关理论分析的基础上,研究了绝热快速通道(ARP)技术控制基态原子的相干性及其布居数在不同能态间的转移,并运用密度矩阵方程与麦克斯韦方程联合的自洽方程数值解,获得了实现原子布居数在不同能态间完全转移的条件,只要选择好两脉冲的输入次序和延迟时间,就可以很好地控制粒子数,以达到我们所需的各种结果.     

大气温度随高度变化率的推导

在对流层内,运用理想气体绝热过程的理想模型,从理论上定性分析了大气温度随高度升高而下降的原因,定量推导了其变化率,并把结果与实际测量值进行了比较分析。     

超强磁场中H2^＋能级的B样条计算与绝热近似结果的比较

用B-splines技术将波函数在径向和角向同时展开,考虑两核之间的相互作用,计算超强外磁场中,氢分子离子基态（m=0）和低激发态（m=-1,-2,-3,-4）的能级与两核间距离的关系,计算结果在2．35×10^6→2．35×10^8T整个区域比绝热近似结果的精度提高0．01到0．02．     

45钢绝热剪切变形数值模拟

采用Ansys／Lsdyna对SHPB加载条件下不同热处理状态的45钢进行了2D数值模拟,数值重现了帽型试样高应变条件下的绝热剪切变形历程。计算中采用二维轴对称应变条件下的两种网格模型,材料本构方程采用热粘塑性Johnson-Cook本构关系,基于应力塌陷绝热剪切形成判据和等效应力-时间曲线分析了绝热剪切变形规律。计算结果表明,绝热剪切敏感性与加载速率和材料的组织结构密切相关。     

硅藻土沥青及沥青混合料低温抗裂机理(英文)

对一种基质沥青和3种硅藻土沥青进行了差示热扫描分析,并结合相应的混合料约束试件的温度应力试验分析了硅藻土沥青的低温抗裂机理.结果表明:硅藻土沥青有优于基质沥青的低温性能;玻璃态转化温度可以较好地反映硅藻土沥青的低温性能;玻璃态转化温度与破断温度有较高的相关性.另外还进行了相应的4种沥青混合料的低温弯曲试验、低温压缩试验和收缩系数试验.结果表明:硅藻土沥青混合料的低温性能优于基质沥青混合料;硅藻土沥青混合料临界弯曲应变能密度及压缩应变能密度均大于基质沥青混合料;沥青混合料加入硅藻土后收缩系数降低.在此基础上,从混合料收缩性能和破坏能量2个角度分析了硅藻土沥青混合料的低温抗裂机理.     

脱水白蘑菇的热变性温度研究

适于脱水的白蘑菇属于热敏性物料，而目前的脱水工艺中热变性的确定主要由来源于感官的试验所确定。本文对白蘑菇这种加热易变性的物料采用差热扫描分析进行研究，以期在包含上述三类物质的复合体内，找到控制热变性温度的依据。本研究对适于脱水的白蘑菇进行了差热扫描变性分析，得出了五种含水率及五种加热速率下的热变性温度变化规律，并讨论了短期贮藏及瞬时高温对热变性温度区的影响，得出了白蘑菇的含水率、升温速率和瞬时高温     

一种适用于气温空间插值的改进梯度距离平方反比法

针对梯度距离平方反比法（GIDS）在地形起伏剧烈地区气温插值误差偏大的问题,提出一种基于经验气温垂直递减率的改进梯度距离平方反比法（GIDS-EAR）。该方法在进行温度插值时分别考虑了经纬度和海拔高度对气温的影响特性。首先根据气温垂直递减率经验值确定气温与海拔高度的偏回归系数,并利用偏回归系数对样本点气温值进行修正,再将此气温修正值代入多元线性回归模型解算气温与经纬度的偏回归系数,依据GIDS插值公式计算待插值点的温度值。基于1981-2010年四川省及周边省份219个气象观测站的累年月值温度值,将GIDS-EAR法与普通克里金法（OK）、反距离权重法（IDW）和GIDS法进行分析比较,结果表明,GIDS-EAR法得到的年均MAE和RMSE值较OK法分别降低67.71%和68.15%,较IDW法分别降低67.68%和66.45%,较GIDS分别降低25.65%和30.08%。该结果验证了改进方法的有效性及复杂地形下的适用性。