数学建模在应用型人才培养中的作用分析

数学建模可以提升学生综合素质，培养其创新及实践能力，因此，提高高校大学生的数学建模能力，对于培养应用型人才具有十分重要的意义。针对数学建模在应用型人才培养中的作用进行了分析，并提出了若干建议，以提升高校大学生的数学建模能力。     

基于Modelica的载人航天器环热控系统建模仿真

为了给载人航天器乘员营造一个良好的生活工作环境,需要将众多空气环境参数控制在指标范围内。文章结合载人航天器专业知识,基于Modelica统一建模语言建立了一种载人航天器环热控系统仿真分析模型;利用该模型仿真分析了温湿度控制风机取不同转速时,载人航天器空气环境参数随乘员代谢水平的变化趋势。结果表明:在其他参数不变的情况下,温湿度控制风机转速越大,空气温度越低,相对湿度越高;乘员代谢水平变化对空气环境参数有显著影响,通过调节系统运行参数可将各空气参数有效控制在指标范围内。舱体温度与氧分压、二氧化碳分压、舱体相对湿度有密切关系且相互影响,不可单独分析。     

选区熔化过程多尺度多物理场建模研究进展

选区熔化技术是一种基于粉末床的、能够精确成形复杂零件、调控微观组织和性能的金属增材制造技术,其成形过程的计算机模拟对于生产实践具有重要指导意义。综述了国内外的研究现状,首先介绍选区熔化技术的原理及其特点;然后介绍国内外对选区熔化过程已经开展的计算机模拟技术的研究进展;并进一步重点介绍针对电子束选区熔化过程的多尺度多物理场模型,主要包括:(1)微观尺度电子束与材料相互作用的能量吸收模型;(2)细观尺度从铺粉到粉末加热、熔化、流动、沉积成形全过程的模型;(3)宏观尺度零件成形过程模型。     

运输机空投货物建模与任务性能影响因素研究

针对当前运输机空投货物模型可拓展性不强的问题,提出了分离体的建模方法。在无需分析货物与飞机整体质心变化的情况下,分别以货物和飞机为对象进行受力分析,推导了货物与飞机之间的相互作用力,建立了更加贴近实际的运输机单件货物空投和连续空投的动力学模型。最后,通过数值仿真,分析了飞行速度和牵引伞牵引比对空投任务性能的影响。结果表明,飞行速度和牵引比越大,飞机在货物干扰作用下的状态变化量越小。     

Conceptual design of a bioregenerative life support system containing crops and silkworms

This article summarizes a conceptual design of a bioregenerative life support system for permanent lunar base or planetary exploration. The system consists of seven compartments – higher plants cultivation, animal rearing, human habitation, water recovery, waste treatment, atmosphere management, and storages. Fifteen kinds of crops, such as wheat, rice, soybean, lettuce, and mulberry, were selected as main life support contributors to provide the crew with air, water, and vegetable food. Silkworms fed by crop leaves were designated to produce partial animal nutrition for the crew. Various physical-chemical and biological methods were combined to reclaim wastewater and solid waste. Condensate collected from atmosphere was recycled into potable water through granular activated carbon adsorption, iodine sterilization, and trace element supplementation. All grey water was also purified though multifiltration and ultraviolet sterilization. Plant residue, human excrement, silkworm feces, etc. were decomposed into inorganic substances which were finally absorbed by higher plants. Some meat, ingredients, as well as nitrogen fertilizer were prestored and resupplied periodically. Meanwhile, the same amount and chemical composition of organic waste was dumped to maintain the steady state of the system. A nutritional balanced diet was developed by means of the linear programming method. It could provide 2721 kcal of energy, 375.5 g of carbohydrate, 99.47 g of protein, and 91.19 g of fat per capita per day. Silkworm powder covered 12.54% of total animal protein intakes. The balance of material flows between compartments was described by the system of stoichiometric equations. Basic life support requirements for crews including oxygen, food, potable and hygiene water summed up to 29.68 kg per capita per day. The coefficient of system material closure reached 99.40%.     

基于ATML标准的ATS软件建模技术

论述了国外ATML标准体系结构和构成ATML标准所有子模型的描述方法,提出了在现有ATS软件平台基础上,实现兼容ATML标准所需的建模流程设计、模型识别及模型运行流程设计等技术途径,为实现ATS软件平台的通用性、开放性及武器装备各种维护级别的测试资源的共享奠定了技术基础。     

Longitudinal variation of the equatorial ionosphere: Modeling and experimental results

We describe a new version of the Parameterized Regional Ionospheric Model (PARIM) which has been modified to include the longitudinal dependences. This model has been reconstructed using multidimensional Fourier series. To validate PARIM results, the South America maps of critical frequencies for the E (foE) and F (foF2) regions were compared with the values calculated by Sheffield Plasmasphere-Ionosphere Model (SUPIM) and IRI representations. PARIM presents very good results, the general characteristics of both regions, mainly the presence of the equatorial ionization anomaly, were well reproduced for equinoctial conditions of solar minimum and maximum. The values of foF2 and hmF2 recorded over Jicamarca (12°S; 77°W; dip lat. 1°N; mag. declination 0.3°) and sites of the conjugate point equatorial experiment (COPEX) campaign Boa Vista (2.8°N; 60.7°W; dip lat. 11.4°; mag. declination −13.1°), Cachimbo (9.5°S; 54.8°W; dip lat. −1.8°; mag. declination −15.5°), and Campo Grande (20.4°S; 54.6°W; dip lat. −11.1°; mag. declination −14.0°) have been used in this work. foF2 calculated by PARIM show good agreement with the observations, except during morning over Boa Vista and midnight-morning over Campo Grande. Some discrepancies were also found for the F-region peak height (hmF2) near the geomagnetic equator during times of F₃ layer occurrences. IRI has underestimated both foF2 and hmF2 over equatorial and low latitude sectors during evening-nighttimes, except for Jicamarca where foF2 values were overestimated.     

Quantifying the role of solar radiative forcing over the 20th century

The 20th century temperature anomaly record is reproduced using an energy balance model, with a diffusive deep ocean. The model takes into account all the standard radiative forcings, and in addition the possibility of a non-thermal solar component. The model is parameterized and then optimized to produce the most likely values for the climate parameters and radiative forcings which reproduce the 20th century global warming. We find that the best fit is obtained with a negligible net feedback. We also show that a non-thermal solar component is necessarily present, indicating that the total solar contribution to the 20th century global warming, of ΔT_solar = 0.27 ± 0.07 °C, is much larger than can be expected from variation in the total solar irradiance alone. However, we also find that the largest contribution to the 20th century warming comes from anthropogenic sources, with ΔT_man = 0.42 ± 0.11 °C.     

组合升力体动力学建模与仿真

设计了组合升力体总体布局，提出了新的组合升力体建模思路与方法，建立了完整的组合升力体飞行动力学数值仿真模型。建模时综合考虑了主要气动力部件的建模，详细讨论了旋翼／固定翼过渡飞行模式的建模方法。根据提出的建模方法进行了组合升力体的操纵响应分析，仿真结果证明了建模理论和方法的合理性和有效性。     

DORIS processing at the European Space Operations Centre

This paper gives an overview of the DORIS related activities at the Navigation Support Office of the European Space Operations Centre. The DORIS activities were started in 2002 because of the launch of the Envisat satellite where ESOC is responsible for the validation of the Envisat Precise Orbits and a brief overview of the key Envisat activities at ESOC is given. Typical orbit comparison RMS values between the CNES POE (GDR-C) and the ESOC POD solution is 6.5, 18.8 and 23.1 mm in radial-, along- and cross-track direction. In the framework of the generation of the ITRF2008 ESOC participated in the reprocessing of all three space geodetic techniques; DORIS, SLR, and GPS. Here the main results of our DORIS reprocessing, in the framework of the International DORIS Service (IDS), are given. The WRMS of the weekly ESOC solution (esawd03) for the 2004–2009 period compared to the IDS-1 combined solution is of the order of 12 mm. Based on the long time series of homogeneously processed data a closer look is taken at the estimated solar radiation pressure parameters of the different satellites used in this DORIS analysis. The main aim being the stabilization of the Z-component of the geocentre estimates. We conclude that the ESOC participation to the IDS ITRF2008 contribution has been beneficial for both ESOC and the IDS. ESOC has profited significantly from the very open and direct communications and comparisons that took place within the IDS during the reprocessing campaign.