大气痕量气体NO_2的研究

为了测量大气中NO_2的含量,我们研制了自动太阳光谱光度仪。在地面遥感测量太阳直射光谱的4470—4490波段,从辐射传输方程及极大相似法,导出了大气中NO_2的含量。而大气中NO_2的浓度,在北京郊区测量了数月。本文对测量结果进行了讨论。     

通过脱碳控制全球平均温度

Establishing a reliable method to predict the global mean temperature (T_e) is of great importance because CO₂ reduction activities require political and global cooperation and significant financial resources. The current climate models all seem to predict that the earth's temperature will continue to increase, mainly based on the assumption that CO₂ emissions cannot be lowered significantly in the foreseeable future. Given the earth's multifactor climate system, attributing atmospheric CO₂ as the only cause for the observed temperature anomaly is most likely an oversimplification; the presence of water (H₂O) in the atmosphere should at least be considered. As such, T_e is determined by atmospheric water content controlled by solar activity, along with anthropogenic CO₂ activities. It is possible that the anthropogenic CO₂ activities can be reduced in the future. Based on temperature measurements and thermodynamic data, a new model for predicting T_e has been developed. Using this model, past, current, and future CO₂ and H₂O data can be analyzed and the associated T_e calculated. This new, esoteric approach is more accurate than various other models, but has not been reported in the open literature. According to this model, by 2050, T_e may increase to 15.5 ℃ under "business-as-usual" emissions. By applying a reasonable green technology activity scenario, T_e may be reduced to approximately 14.2 ℃. To achieve CO₂ reductions, the scenario described herein predicts a CO₂ reduction potential of 513 gigatons in 30 years. This proposed scenario includes various CO₂ reduction activities, carbon capturing technology, mineralization, and bio-char production; the most important CO₂ reductions by 2050 are expected to be achieved mainly in the electricity, agriculture, and transportation sectors. Other more aggressive and plausible drawdown scenarios have been analyzed as well, yielding CO₂ reduction potentials of 1051 and 1747 gigatons, respectively, in 30 years, but they may reduce global food production. It is emphasized that the causes and predictions of the global warming trend should be regarded as open scientific questions because several details concerning the physical processes associated with global warming remain uncertain. For example, the role of solar activities coupled with Milankovitch cycles are not yet fully understood. In addition, other factors, such as ocean CO₂ uptake and volcanic activity, may not be negligible.     

加工误差对气体静压径向轴承的影响

建立了一种考虑影响气膜厚度误差、圆度和圆柱度误差的气膜厚度分布综合表达式,考虑加工误差对气体静压径向轴承的影响,进行了气体润滑有限元分析.分析表明:圆度和圆柱度误差对轴承的承载能力影响不大;气膜厚度误差为平均气膜厚度的5%时,承载能力变化约为10%.     

斜交断层工作面内部留巷技术应用

龙湖分公司31001工作面倾斜长105m，煤层倾角33m，煤层厚度平均为7m，工作面采用2．2m“π”型钢梁，单体液压支柱二梁五柱支护顶板，一次采全高，工作面在回采过程中距离采线100m时，上顺槽由三石门向二石门掘进30m时停掘。根据石门煤厚资料，上二石门煤厚2米，下一石门煤厚0．7米，上j倾槽改由上二石门向三石门掘进，由于受断层影响，煤层由2米迅速变成0．8米，掘至25米时完全消失，     

纯铜表面稀土渗铝层的内氧化

利用稀土化合物CeCl3对纯铜表面渗铝进行催渗。采用工业N2中的余氧作为内氧化介质对纯铜渗铝后的试样进行内氧化，可在纯铜表面制备一层细小弥散的Al2O3粒子。对内氧化层的硬度分布、显微组织及有关性能进行了初步分析。实验结果表明：稀土化合物CeCl3对纯铜渗铝过程具有明显的催渗效果，在同等工艺条件下渗层厚度较高且更加均匀；内氧化后，能在渗铝层形成Al2O3弥散硬化层。     

无线光通信在电力系统中应用的分析

本文结合电力系统的通信需求,分析了这一技术在电力通信网中的优越性、应用方式和关键技术,并讨论了其在电力系统中的应用前景.     

大气混合层厚度的计算方法及影响因子

本文讲述了大气混合层厚度的定义及它在大气环境保护中的作用。论述了大气混合层厚度的多种计算方法如国标法、干绝热法、罗氏法等，并分析了大气混合层厚度的各种影响因子。其中大气稳定度是决定混合层厚度的最主要因子。     

用差压新方法确定模型环道蜡沉积厚度

用于计算模型环道蜡沉积厚度的传统差压法未考虑测试段流场畸变对测试段压差的影响。利用Fluent软件对测试段的流场和温度场进行了数值模拟，考虑到近壁处油温的下降及管内流场的畸变，给出了确定蜡沉积厚度的差压新方法。模拟结果表明，在测试段管外冷却水的作用下，近壁处油温低于管中心附近的油温；冷却水与管壁的换热热阻及钢管管壁的导热热阻的存在使贴壁处油温与冷却水的温度有差异，离测试段入口越远，它们之间的差值越小，管内速度分布发生畸变(近壁处流速减小，管中心附近流速增大)，管段压差增大。流场畸变造成管段压降增加近10％。     

曲轴轴颈轮廓形状对轴承使用性能的影响

曲轴轴颈母线形状对轴承使用性能影响巨大，从工厂曲轴的实际使用情况出发，列出了几种常见的曲轴轴颈廓形在工作时与之相配轴瓦的实际磨损情况，初步分析了出现这种情况的原因；并运用弹性流体动力润滑理论对曲轴轴颈油膜厚度进行了计算，验证了实际使用时出现的结果．     

差分吸收光谱技术及在大气监测领域中的应用

差分吸收光谱技术(DOAS：Differential Optical Absorption Spectroscopy)是一种光谱监测技术，其基本原理就是利用空气中的气体分子的窄带吸收特性来鉴别气体成分，并根据窄带吸收强度来推演出微量气体的浓度。凭借其低廉且简单的设备装置和出色的监测能力，DOAS技术在大气监测领域内在国外已经被广泛应用。鉴于国内的污染形势的日益严峻及对此新兴技术知识的匮乏。对于DOAS技术的工作原理、浓度反演方法及其在大气研究领域内的应用与发展前景做了较为详细的介绍，为今后在大气监测领域里研究和应用DOAS技术提供了必要的理论知识。