Puhimau Thermal Area: A Window into the Upper East Rift Zone of Volcano, Hawaii?

We report the results of two soil CO₂ efflux surveys by the closed chamber circulation method at the Puhimau thermal area in the upper East Rift Zone (ERZ) of volcano, Hawaii. The surveys were undertaken in 1996 and 1998 to constrain how much CO₂ might be reaching the ERZ after degassing beneath the summit caldera and whether the Puhimau thermal area might be a significant contributor to the overall CO₂ budget of . The area was revisited in 2001 to determine the effects of surface disturbance on efflux values by the collar emplacement technique utilized in the earlier surveys. Utilizing a cutoff value of 50 g m⁻² d⁻¹ for the surrounding forest background efflux, the CO₂ emission rates for the anomaly at Puhimau thermal area were 27 t d⁻¹ in 1996 and 17 t d⁻¹ in 1998. Water vapor was removed before analysis in all cases in order to obtain CO₂ values on a dry air basis and mitigate the effect of water vapor dilution on the measurements. It is clear that Puhimau thermal area is not a significant contributor to CO₂ output and that most of CO₂ (8500 t d⁻¹) is degassed at the summit, leaving only magma with its remaining stored volatiles, such as SO₂, for injection down the ERZ. Because of the low CO₂ emission rate and the presence of a shallow water table in the upper ERZ that effectively scrubs SO₂ and other acid gases, Puhimau thermal area currently does not appear to be generally well suited for observing temporal changes in degassing at .     

时间序列分析在电离层短期预报中的应用

根据IGS提供的2012年TEC数据,在得到TEC值残差序列的基础上,利用谱分析去掉周期项和Matlab工具箱去掉趋势项并采用平滑算法去噪后,对随机项进行时间序列分析。目前,电离层格网点的预报均建立在原始TEC上,阐述了采用差分后的TEC值进行预报的方法,以减少日变化周期项的影响。根据AR（p）模型预报的结果加上周期项和趋势项后,再加上前一天对应时段的TEC值与IGS发布的数据比较,结果表明,该方法利用短期IGS发布的TEC值进行电离层预报能取得较高的精度。     

基于汶川主震及余震的预警参数与震级相关性研究

地震预警作为一种能够有效减轻地震灾害的手段已经被世界上越来越多的国家和地区所研究,并在实际应用中取得了显著的减灾实效.利用汶川主震及其余震P波和S波初期部分的信息,研究了最终地震震级与4个预警参数的相关性.考察的4个参数是位移幅值(P_d)、速度平方积分(IV2)、P波卓越周期和特征周期(τ_p和τ_c).使用的数据集时间跨度从2008年5月12日至2008年10月4日,共计218次震级大于等于4级的地震事件,包括主震8.0、最大余震6.5和7次大于等于6.0级的事件.P_d、IV2和τ_c在震级小于等于6.5级时与最终震级具有较好的相关性,没有出现震级饱和现象,验证了前人的统计结果.但是在估算主震震级时,都存在不同程度的低估现象,IV2参数尤其明显.另外,P_d和IV2统计曲线在M6级附近存在着一个斜率变化,并且P_d结果与前人统计结果相差较大.τ_p的统计结果表明该参数不适合应用到汶川地区的地震预警系统中.     

Centrifuge modelling of lateral loading behaviour of a “semi-rigid” Mono-pile in soft clay

Abstract

Mono-pile foundations have been widely used for offshore wind turbines principally due to their convenient construction and cost-effective nature. So far, little attention has been paid to large diameter “semi-rigid” piles that have distinct behaviours from flexible or ideally rigid piles. This paper presents a series of centrifuge model tests to study the deforming and bearing characteristics of a 5.9 dia. semi-rigid pile under lateral loadings in kaolin clay. For monotonic loading, a modified p–y curve analysis model considering rotational soil flow near the rotation centre of pile was proposed, highlighting the limitation of classic plane-strain based plasticity models to evaluate the ultimate lateral pile-soil resistance. For cyclic loading, a strong correlation between the degree of soil degradation and cyclic load amplitude was identified. Besides, a degradation factor model, accounting for various cyclic stress levels and soil depths, was proposed, which can be used to assess the accumulative displacement of semi-rigid piles under cyclic loadings in soft clay.     

基于平稳自回归模型的地表移动变形预测

采用AR(p)模型描述随机过程本身观测数据之间的相互关系,根据实测数据建立随机预测模型,对后三期变形量进行预报,并与实测数据进行比较,预报效果良好。     

PSO-GM(1,1,N,p,ξ)模型在变形预测中的应用

通过对传统GM(1,1)缺陷分析和改进的基于权的PGM(1,1)建模机理描述,顾及PGM(1,1)中背景值构造时取相同的参数不能充分降低模型的预测误差,对不同的时刻引入不同的参数来改进GM(1,1)背景值序列的计算公式,将这种背景值构造方法和灰元N引入GM(1,1)建立了新的白化方程。在建立的新的白化方程基础上,用龙格-库塔法以修正的初始值计算累加值的模拟序列。针对引入的参数较多问题,采用粒子群算法寻找满足相对误差均值最优的参数,从而建立了基于粒子群优化算法和加权灰色组合的PSO-GM模型。工程实例应用表明,新模型的拟合精度高,预测效果好,相对其他两种原有模型预测精度有明显提高。     

Gravity Modes in Delta Scuti Stars

This paper examines the observational evidence for the detectionof gravity modes in Scuti stars, which are p-mode pulsators.Low-order gravity modes have also been found in at least one star (FG Vir).Some reports of gravity modes may be due to systematic errors in theabsolute magnitude calibrations for slowly rotating stars. Furthermore,many detected low frequencies are not high-order gravity modes, but linear combinations,f _i -f _j , of the main pulsation modes. Other low frequencies are caused bya close binary companion leading to tidal deformation as well as tidallyexcited gravity modes.     

对羧基偶氮氯膦与锆显色反应及应用

在０５６ｍｏｌ／ＬＨＮＯ３介质及溴化十六烷基吡啶存在下，Ｚｒ（Ⅳ）与对羧基偶氮氯膦形成１∶２的蓝色络合物。其λｍａｘ＝６８５ｎｍ，ε６８５＝６８５×１０４，Ｚｒ（Ⅳ）的质量浓度为在０～０８ｍｇ／Ｌ时符合比尔定律。所建立的方法用于熔铸氧化铝和陶瓷釉料中Ｚｒ的测定，结果与推荐值相符，对于ｗ（Ｚｒ）＝１１８％熔铸氧化铝测定６次，其ＲＳＤ＝０８８％。