Methane emissions from terrestrial plants over China and their effects on methane concentrations in lower troposphere

Methane (CH₄) is the most important greenhouse gas and reactive trace gas in the atmosphere. Recently, it has been reported that terrestrial plants can emit CH₄ under aerobic conditions, which may call for reevaluation of the inventory of CH₄ emissions in China. In this paper, those emissions over China and their effects on CH₄ concentrations in lower troposphere were investigated. Firstly, based on the work of Keppler et al., the aerobic plant CH₄ emission model (PLANTCH4) for China was established. And by using the database of normalized difference vegetation index (NDVI) derived from NOAA/AVHRR, the distribution of net primary productivity (NPP) over China was simulated, and thereby, for the first time, the amount and distribution of the newly identified source in China were estimated. Secondly, with the aid of the three-dimensional atmospheric chemistry model system (MM5-CALGRID), the effects of the emissions were studied. The results show that the annual aerobic plant CH4 emissions over China amount to 11.83 Tg, i.e. nearly 24% of Chinese total CH₄ emissions. And the major fraction (about 43%) comes from forests. When those emissions are considered in modeling, computed countrywide mean surface concentration of CH₄ is 29.9% higher than without them, with a maximum increase of 69.61 μg·m⁻³ in the south of Yunnan Province. In conclusion, to study CH₄ emissions from terrestrial plants over China may have important implications for correctly estimating the contribution of China to global CH₄ budget, and may call for a reconsideration of the role of CH₄ in global and regional environment and climate change. Supported by National High-Tech Research & Development Program of China (Grant No. 2006AA06A307), National Basic Research Program of China (Grant Nos. 2006CB403706 and 2006CB403703), and the Program for New Century Excellent Talents in University, and Nanjing University Talent Development Foundation     

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利用直接积分法结合子结构技术和网络并行计算的特点,提出了一种求解结构动力应的网络并行解法。该方法在并行形成各子结构的劲度矩阵、质量矩阵,阻尼矩阵及荷载列阵后,并行进行各子结构的静凝聚,然后采用并行子结构预条件共轭梯度法迭代求解结点位移,从而确定结构的动响应。算例表明,随着子结构内点数和时间积分步数的增加,能获得较高的加速比。     

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SHL6.5t／h锅炉掺烧无烟煤及扩容技术改造

论述了ＳＨＬ６．５ｔ／ｈ锅炉改造后掺烧６０％－７０％无烟煤的方法，并使锅炉的产汽量增加到８ｔ／ｈ，改造中采用了人字拱，热管式换热器等我技术，取得了显著的经济效益。     

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采用农膜、根宝、生根粉、保水剂在干旱地区对刺槐造林成活率进行了田间对比试验。结果表明：农膜、根宝对提高造林成活率的影响显著高于常规造林方法，分别提高43．63％，36．36％，而生根粉和保水剂与常规造林法比较差异不显著。4种产品中根宝的经济适用性优于其它产品。     

为语言学中的某些术语正名

本文主要对现代语言学中一些不尽合理的术语加以分析,并提出了应该采用的科学合理的术语;同时对一些尚未引起注意的文字间的关系,进行了分析说明。     

《汇编语言》课程设计的改革与实践

本通过对《汇编语言》课程设计各环节的深刻讨论，在总结以往工作经验的基础上，为读推荐了一种较实用的《汇编语言》课程设计的改革方案，经实践检验具有一定的推广价值。     

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