红外热波成像法测量薄板局部换热系数

通过连续激光调制对薄板试样进行局部周期加热，采用红外扫描测温技术记录动态温度分布。利用博里叶变换分析温度基波相位和幅值变化，进而推算壁面的局部换热系数。介绍了该方法的测量原理，在风洞中对两种不同厚度的薄板进行了实验研究，并对实验结果进行了分析和讨论。     

X-ray radiation from accreting, magnetized neutron stars

A review is given of recent developments in the theory of emission from a magnetized plasma for accreting neutron star conditions. Some observational data on X-ray pulsars are discussed, and present problems are indicated.     

热防护系统的硅纤维隔热层复合传热数值计算

鉴于热防护系统的硅纤维隔热层是各向异性的非灰体材料，其复合传热计算是复杂且耗时的，提出了一种简便方法用于硅纤维这类各向异性非灰体材料的复合传热计算。该方法借鉴了医学领域断层摄影法（局部X射线检测法）中对光沿各向异性散射介质传播分析的思路，得到了各向异性扩散的热辐射方程（RTE—D）并把该方程用于求解非灰体半透明介质的辐射热通量。计算结果与文献中基于辐射传递方程（RTE）求得辐射热流的复合传热数值结果相比较，其最大相对误差为1．5％，并且其计算时间也由Pentium Ⅱ的3297．66分钟缩短为PentiumⅣ的约5分钟。最后，该方法被用于真实热环境下刚性隔热瓦L1900（高空隙率硅纤维隔热材料）的复合传热计算，计算结果与实验数据有较高吻合度。数据结果表明，各向异性的扩散近似被用于求解非灰体半透明介质的辐射热通量的方法用在热防护系统的硅纤维隔热层复合传热数值计算中是简便高效的。     

燃气源控制气流热效应数值模拟研究

为了解迷宫形导热套环与流体之间的热交换对控制气流温度及压力的影响,采用整体求解法求解控制气流与多层套环之间的耦合传热问题。为确保计算结果在物理上的真实性,采用“假密度法”求解以温度T为求解变量的能量方程。计算得到了控制气流参量随时间的变化情况以及迷宫形多层导热套环的温度在不同时间点的分布情况,结果表明流场的三维复杂结构使得每个小孔射流与各层套环的传热情况都不同,流体与固体区域之间的换热量随时间变化,其中内套环和中套环对流体的吸热量随时间的增长而急速下降,从而导致控制气体的温度和压力都随时间而逐渐增大。计算所得的控制气流温度和压力与试验测量值的变化趋势相同,验证了计算方法的有效性。     

德国双元制教育模式及对我国高等职业教育的启示

德国的双元制教育模式是世界上最先进的职业教育模式之一。从双元制职业教育的发展背景、动态及这种教育模式的具体实施出发,阐述这种教育模式对我国高等职业教育的借鉴和启示。     

Influence of ionospheric perturbations in GPS time and frequency transfer

The stability of GPS time and frequency transfer is limited by the fact that GPS signals travel through the ionosphere. In high precision geodetic time transfer (i.e. based on precise modeling of code and carrier phase GPS data), the so-called ionosphere-free combination of the code and carrier phase measurements made on the two frequencies is used to remove the first-order ionospheric effect. In this paper, we investigate the impact of residual second- and third-order ionospheric effects on geodetic time transfer solutions i.e. remote atomic clock comparisons based on GPS measurements, using the ATOMIUM software developed at the Royal Observatory of Belgium (ROB). The impact of third-order ionospheric effects was shown to be negligible, while for second-order effects, the tests performed on different time links and at different epochs show a small impact of the order of some picoseconds, on a quiet day, and up to more than 10 picoseconds in case of high ionospheric activity. The geomagnetic storm of the 30th October 2003 is used to illustrate how space weather products are relevant to understand perturbations in geodetic time and frequency transfer.     

河南省产业集群与城市经济的关系研究

随着产业集群的不断发展，其对城市经济的影响越来越显著，对两者之间关系的研究势在必行。文章运用回归分析法对城市经济与产业集群之间的关系进行定量研究，认为二者的关系主要体现在以下几个方面：（1）产业集群可以有效促进城市经济发展；（2）产业集群内组织间联系紧密程度决定其对城市经济发展的潜在贡献；（3）产业集群对城市经济的促进依赖于政府的支持程度；（4）产业集群对城市经济的促进依赖于城市人文环境。文章的研究为河南省制定城市经济发展战略、促进产业集群发展提供了量化依据。     

New field of application of the IRI modeling – Determination of ionosphere transfer characteristic for radio astronomical signals

We suggest a new field of application of IRI modeling – determination of ionosphere transfer characteristic (ITC) for radio astronomical signals (RAS). VHF and HF RAS are widely used for observations of the Sun and pulsars. It is necessary to take into account possible distortions of RAS in the Earth ionosphere. However, in contrast to modern navigation systems (GPS, GLONASS, GALILEO), where very accurate reconstruction of ionosphere parameters is a built-in function, in present-day radio astronomy a retrieve of ITC has not been appropriately worked out yet. It collides with increasing requirements to accuracy of the analysis of RAS amplitude profile and to the angular and polarizing resolution of radio telescopes of new generation. We have developed a method and software for calculation of the ionosphere measure of rotation (RM) and the measure of dispersion (DM). We used the ionosphere model IRI-2001, magnetic-field model IGRF-10 and values of ionosphere total electron content as deduced from GPS measurements. The obtained values of the ionosphere DM and RM were recalculated into characteristics of phase delay, Faraday amplitude modulation and polarization changes. We made calculations for different levels of geomagnetic activity and for different angular position of radio sources as well.     

安徽省生产性服务业和制造业融合发展研究

产业融合是现代产业发展的必然结果,利用2002-2007年安徽省投入产出表相关数据,结合中间投入率和中间需求率,对安徽省生产性服务业和制造业间的融合度进行测算,探究安徽省产业融合特点和规律,旨在为安徽省产业结构调整和转型升级提供科学依据。研究表明:整体制造业和生产性服务业相互依赖,融合程度在不断加深,生产性服务业的投入主要集中在劳动和资源密集型产业,对技术密集型产业的投入较低,不同生产性服务业对整体制造业的投入结构存在明显差异。     

Optimal steering law of refractive sail

The interaction between electromagnetic waves and matter is the working principle of a photon-propelled spacecraft, which extracts momentum from the solar radiation to obtain a propulsive acceleration. An example is offered by solar sails, which use a thin membrane to reflect the impinging photons. The solar radiation momentum may actually be transferred to matter by means of various optical phenomena, such as absorption, emission, or refraction. This paper deals with the novel concept of a refractive sail, through which the Sun’s light is refracted by crossing a film made of polymeric micro-prisms. The main feature of a refractive sail is to give a large transverse component of thrust even when the sail nominal plane is orthogonal to the Sun-spacecraft line. Starting from the recent literature results, this paper proposes a semi-analytical thrust model that estimates the characteristics of the propulsive acceleration vector as a function of the sail attitude angles. Such a mathematical model is then used to analyze a simplified Earth-Mars and Earth-Venus interplanetary transfer within an optimal framework.