Improving the CoLM in Taklimakan Desert Hinterland with Accurate Key Parameters and an Appropriate Parameterization Scheme

Improving and validating land surface models based on integrated observations in deserts is one of the challenges in land modeling. Particularly, key parameters and parameterization schemes in desert regions need to be evaluated in-situ to improve the models. In this study, we calibrated the land-surface key parameters and evaluated several formulations or schemes for thermal roughness length （z 0h ） in the common land model （CoLM）. Our parameter calibration and scheme evaluation were based on the observed data during a torrid summer （29 July to 11 September 2009） over the Taklimakan Desert hinterland. First, the importance of the key parameters in the experiment was evaluated based on their physics principles and the significance of these key parameters were further validated using sensitivity test. Second, difference schemes （or physics-based formulas） of z 0h were adopted to simulate the variations of energy-related variables （e.g., sensible heat flux and surface skin temperature） and the simulated variations were then compared with the observed data. Third, the z 0h scheme that performed best （i.e., Y07） was then selected to replace the defaulted one （i.e., Z98）; the revised scheme and the superiority of Y07 over Z98 was further demonstrated by comparing the simulated results with the observed data. Admittedly, the revised model did a relatively poor job of simulating the diurnal variations of surface soil heat flux, and nighttime soil temperature was also underestimated, calling for further improvement of the model for desert regions.

STRUCTURE PARAMETERS DESIGN AND PERFORMANCE TEST OF FUEL INJECTION SYSTEM

Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.

标准件和常用件可视参数化绘图系统的开发

在各种机器、仪表和电器设备中,机械标准件和常用件是设计中常用的零部件。国家标准中,对标准件和常用件的结构要素的表达制定了一系列规定画法,通过查表就可以知道相关尺寸。遵守这些标准可以有效的提高设计的速度和质量。AutoCAD软件中没有标准件和常用件库,论述了运用VBA设计、调用标准件和常用件可视参数化绘图系统的方法,进而提高了绘图机械图样的效率,扩充了AutoCAD的功能。

青藏高原夏季土壤有机质及砾石影响水热传输特性的数值模拟

本文针对青藏高原部分地区土壤有机质和砾石含量较高的特点,在前人工作的基础上,发展了一个新的参数化方案以描述土壤有机质和砾石对土壤导热率、导水率的影响。通过对通用陆面模式CoLM中的土壤水、热参数化方案以及地表蒸发阻抗三方面的逐步改进,对青藏高原藏东南站和纳木错站两种不同下垫面进行单点数值模拟分析。对比原方案与最终优化方案的模拟结果表明:采用新方案的CoLM模式对藏东南站土壤湿度模拟性能明显提高,平均偏差减小到0.04,而对纳木错站浅层20 cm以上土壤湿度的模拟偏差略微增大。新方案在藏东南站对土壤内部温度的模拟改善较为显著,平均偏差减小了0.2°C;而在纳木错站40 cm以上有所改进。新参数化方案较好地模拟了两个观测站表面能量通量的时间变化,纳木错站7、8月份的潜热通量改进尤为明显,比原方案减少大约20 W m-2,与观测结果较为接近。

化工设备常用结构的参数化CAD设计

采用Ａｕｔｏｌｉｓｐ语言开发了绘图环境初始化设计、固定管板换热器中管板的参数化设计以及化工设备焊接节点图的参数化设计程序。程序的使用大大提高了设计效率，保证了设计质量。

化工设备通用零部件的参数化设计

利用Visual Basic6.0为开发工具,以AutoCAD2000为二次开发平台实现了化工设备通用零部件的参数化设计。该系统可大大减轻设计人员的工作强度、提高绘图效率、缩短产品的开发周期。

Maximum Posterior Adjustment of Extended Network and Estimation Formulae of Its Variance Components

This paper derives the maximum posterior adjustment formulae of the extended network and the estimation formulaes of variance components of Helmert, Welsch and Frstner types when there are two types of uncorrelated observations in it, and perfects the theory of the maximum posterior adjustment.

基于AutoCAD环境下常用结构的参数化设计

AutoCAD是机械设计人员最常用的绘图工具,功能非常强大,但常因缺乏常用结构图形库而影响绘图效率,为此,论文提出在AutoCAD环境下采用AutoCAD VBA方式对机械图形中的常用结构进行参数化设计的解决方案。由于常用结构的开发方式类似,便以轴类零件中键槽结构的主视图和剖面图为例,讲述了Access数据库的构建方法、利用ADO方式来开发数据库的过程和编程实现最终图形的过程。

荒漠下垫面陆面过程模式中重要参数的修正及模拟效果分析

通过对内蒙古阿拉善左旗荒漠下垫面观测数据的分析和模拟,重新修正了陆面过程模式Co LM中的重要参数值和参数化方案,并按照不同的组合方式设计了控制实验和敏感性实验,对比分析重要参数对该下垫面陆气相互作用的敏感性。主要结论有:(1)基于Monin-Obukhov相似性理论的最大频数法,优化了地表动力学粗糙度,重新计算和选择符合研究区域地表热力学粗糙度和土壤热导率的参数化方案;(2)参数优化和参数化方案修正后,提高了Co LM模式对土壤温度,感热通量和地表净辐射的模拟能力;(3)改善前后Co LM模式的模拟值与观测值对比表明,地表动力学与热力学粗糙度和土壤热导率分别在春夏季和秋冬季对地表温度影响较大,感热通量在夏半年主要对地表动力学粗糙度敏感,而土壤热导率对其影响很小。