Soil Organic Carbon Contents and Stocks in Coastal Salt Marshes with Spartina alterniflora Following an Invasion Chronosequence in the Yellow River Delta,China

Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m~2) were significantly increased(P 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R~2 = 0.43, P 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.     

黄海西北近岸沉积物中细菌群落空间分布特征

采用16S rDNA文库和变性梯度凝胶电泳(DGGE)技术,对黄海西北部3个近岸站位沉积物中细菌群落多样性及空间分布特征进行了调查和解析。对表层沉积物16S rDNA序列统计表明,各站位细菌群落多样性很高,γ-和δ-变形菌纲分别占克隆序列总数的20%~32%,是沉积物中的绝对优势类群。DGGE图谱分析表明,同一站位中不同深度的细菌群落结构相似性较高,而不同站位间群落结构相差较远。研究表明在黄海西北近岸沉积物中细菌群落多样性较高,优势类群明显,在较小尺度范围内群落结构的垂直变化不明显。     

桂林柑桔主要病虫害发生的气象条件分析

通过桂林地区柑桔主要病虫害发生发展的气象条件分析,找出了病虫害的发生发展与气象条件的关系很密切。     

新疆伊吾县马依当地区二叠纪地层的发现及其意义

在新疆伊吾煤矿一带1:5万区域地质矿产调查中,首次在原定石炭系上统妖魔梁组中发现大量透镜状钙质结核,并具明显的陆相冲积扇沉积特征;通过该地层的大量孢粉鉴定属为二叠世晚期,故将原石炭系上统妖魔梁组更名改为库莱组。其时代定为晚二叠世。并初步探讨了它的地质意义。     

1991年大同—阳高5.8级地震的序列

对1991年3月大同—阳高5.8级地震的震源特点、序列特征及震前序列活动进行了分析研究,得出这次5.8级地震是1989年大同—阳高地震的晚期强余震、地震子序列为主余震型序列的结论。从1989年以来大同老震区的弱震活动分析表明,其弱震的几个起伏是大同及其周围应力场加强的信号,可作为今后地震监测预报的窗口。     

Determination of kolmogorov entropy of chaotic attractor included in one—dimensional time series of meteorological data

The 1970-1985 day to day averaged pressure dataset of Shanghai and the extension method in phase space are used to calculate the correlation dimension D and the second-order Renyi entropy K2 of the approximation of Kolmogorov’s entropy, the fractional dimension D = 7.7~7.9 and the positive value K2 ≈ 0.1 are obtained. This shows that the attractor for the short-term weather evolution in the monsoon region of China exhibits a chaotic mo-tion. The estimate of K2 yields a predictable time scale of about ten days. This result is in agreement with that ob-tained earlier by the dynamic-statistical approach.The effects of the lag time τ on the estimate of D and K2 are investigated. The results show that D and K2 are convergent with respect to τ. The day to day averaged pressure series used in this paper are treated for the extensive phase space with τ = 5, the coordinate components are independent of each other; therefore, the dynamical character quantities of the system are stable and reliable.     

遥感技术在云南中甸地区煤炭资源调查中的应用

以卫星遥感技术为主要手段,通过遥感地质解译,结合适量的野外调查,综合常规地质资料分析,认为云南中甸地区的含煤目的层为新第三系上新统和第四系更新统。并对该区新生代盆地的形成机制及煤层聚集、赋存规律进行了总结,圈定了5个含煤远景区,为该区进一步进行煤炭资源勘探提供了靶区和基础资料,对解决滇西北严重缺煤的现状有一定的实际意义。     

羌塘中部雀莫正长斑岩体特征及构造意义

雀莫正长斑央全碱含量较高且K2O＞Na2O，富集大离子亲石元素，轻重稀土元素比值较高，稀土元素配分曲线呈斜率较大的右倾式，副矿物组合为磷灰石－榍石－磁铁矿，时代属喜马拉雅期，构造上属造山晚期侵入体。     

模糊数学在混凝土构件耐久性评定中的应用初探

根据钢筋混凝土构件耐久性评估的特点，借助模糊数学的理论，将结构构件的损伤程度作为构件这一论域U上的模糊子集A，利用所构造的多元隶属函数，对构件的损伤程度进行评价，提出了一种耐久性分极评定方法，这一方法克服了以往在结构构件评价中存在的主观、经验等因素，该法的特点是使耐久性的每一级别都有确切的剩余寿命的内涵，而多元隶属函数法的引入减小了主观因素对评定结果的影响。经实例验算，该法准确率可达90%。     

Discrimination between nuclear explosions and earthquakes based on consideration of tectonic ambient shear stress values

IntroductionFor the need of a nuclear test ban treaty, international society must make great efforts to find effective methods for discrimination between earthquake and nuclear explosion. Thereupon, many methods of discrimination of nuclear explosion appeared. But, at present, there is some uncertainty to discriminate middle or small nuclear explosion (Peppin, McEvilly, 1974; Richards, Zarales, 1990). When we study tectonic ambient shear stress field of Southern California, we find that str…