Henry’s law constant for phosphine in seawater: determination and assessment of influencing factors

The Henry’s Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23°C). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry’s Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.     

埋地管线-土横向动力相互作用等效弹簧系数解析解

基于一维柱面弹性波动理论,推导了埋地管线-土横向动力相互作用等效弹簧系数解析表达式,并对该表达式的影响因素,诸如频率(ω)、管线埋深(d)、管线半径(b)、场地波速(VP)、泊松比(μ)的影响程度进行了分析。分析结果表明,无量纲频率bω/VP取较小值时(<0.1),弹簧系数取值随着管线埋深与管线半径之比γ的增加而增大,但总是限制在2.0G～4.0G(G为土体剪切模量)之间,且泊松比对其影响很小,对于工程实际情况,弹簧系数可在该范围内取值。     

海带的碳酸钠消解过程动力学

以海带为原料,考察了消解反应温度、碳酸钠浓度、搅拌速度及海带块尺寸对消解反应动力学、褐藻胶收率及产品黏度的影响。结果表明,随温度、碳酸钠浓度、搅拌速度的升高,消解反应速度明显加快,褐藻胶提取速率随之增大。海带块大小对反应速率也存在一定的影响,海带块越小,褐藻酸钠提取反应速率越快。确定的较佳消解条件为：Na2C03浓度为0．5％,消解温度为60℃,搅拌速度200r／min,海带块尺寸为20mm。在此条件下,产品的产率可超过22％,黏度超过了20000mPa·S。研究结果为优化传统海带消解工艺,节约碱耗,缩短反应时间、提高产品收率和品质提供了参考。     

基于土体小应变本构模型的TRD工法成墙试验数值模拟

等厚度水泥土搅拌墙技术即TRD工法,近年来在深基坑工程中得到了广泛应用。以上海国际金融中心基坑工程开展的0.7 m厚、8 m宽、56.7 m深TRD成墙试验为背景,采用有限元方法,并基于土体小应变本构模型对其成墙过程进行了模拟,得到了土体侧向位移和地表沉降曲线,并与实测数据进行了对比。结果表明,距离墙体5 m处两者的土体侧向位移曲线基本一致,而距离墙体1.4 m处的土体侧向位移在深度大于20 m后的计算结果较实测值偏小;地表沉降在靠近墙体处最大,随着距墙体的距离增大而逐渐减小。最后分析了成墙深度对地表沉降和土体侧向变形的影响,结果表明,深度越深,引起的土体侧向变形和地表沉降也越大。通过不同成墙深度引起的地表沉降归一化曲线可看出,TRD成墙引起的最大地表沉降约为0.05%H（H为成墙深度）,沉降影响区域约为1.8H。     

GS-15型重力仪记录畸变特征分析

通过对成都地震台GS-15型重力仪记录固体潮曲线畸变特征分析,找出记录曲线畸变的变化规律,并对引起该变化的因素、物理机制进行分析。仪器加温系统供电电源性能变差,导致仪器内部恒温系统破坏是引起记录固体潮曲线畸变原因。     

25℃时K2B4O7-H2O体系的离子相互作用模型研究

根据硼酸盐水溶液中硼浓度不同时硼物种之间形成多种聚合与解聚的平衡反应理论和光谱学研究结果,利用已有的该体系25℃等压实验数据,拟合获得了该体系的两个化学计量平衡常数、各种硼氧配阴离子单一的以及二离子和三离子之间的相互作用Pitzer参数,确定了该体系在不同总硼浓度范围内各种硼氧配阴离子的存在形式与定量分布,将所获得的离子相互作用模型计算出的渗透系数与实验值进行了比较,获得了令人满意的结果。     

Convection of a fluid with strongly temperature and pressure dependent viscosity

Plate tectonics on the Earth is a surface manifestation of convection within the Earth’s mantle, a subject which is as yet improperly understood, and it has motivated the study of various forms of buoyancy-driven thermal convection. The early success of the high Rayleigh number constant viscosity theory was later tempered by the absence of plate motion when the viscosity is more realistically strongly temperature dependent, and the process of subduction represents a continuing principal conundrum in the application of convection theory to the Earth. A similar problem appears to arise if the equally strong pressure dependence of viscosity is considered, since the classical isothermal core convection theory would then imply a strongly variable viscosity in the convective core, which is inconsistent with results from post-glacial rebound studies. In this paper we address the problem of determining the asymptotic structure of high Rayleigh number convection when the viscosity is strongly temperature and pressure dependent, i.e. thermobaroviscous. By a method akin to lid-stripping, we are able to extend numerical computations to extremely high viscosity contrasts, and we show that the convective cells take the form of narrow, vertically-oriented fingers. We are then able to determine the asymptotic structure of the solution, and it agrees well with the numerical results. Beneath a stagnant lid, there is a vigorous convection in the upper part of the cell, and a more sluggish, higher viscosity flow in the lower part of the cell. We then offer some comments on the possible meaning and interpretation of these results for planetary mantle convection.     

地震计智能恒温系统的设计与实现

当外界温度急剧变化时,拾震器内部机械结构会受到一定影响,易产生靠摆或零漂等问题。通过温度实验测试研究温度对甚宽频地震计性能影响,并通过研制地震计智能恒温设备来解决此类问题,实时监测防护罩内温度并与已设定温度上下限进行比较,当监测温度高于设定上限温度时启动半导体制冷装置;当监测温度低于设定下限温度时则启动加热装置。为防止防护罩内系统温度急剧变化造成拾震器的机械性故障,加热制冷功率均从最小值开始进行缓慢调整。设备可远程通过网络进行各参数的修改,并可远程启动或关闭加热或制冷装置及其他故障设备。此设备的研制成功可使拾震器长期在稳定的温度环境中工作,减少其各类故障,同时也将最大限度地增加地震仪器的使用年限。     

考虑多种因素影响的海上地震勘探气枪震源单枪子波数值模拟

在分析Ziolkowski气泡振动模型局限性的基础上,建立了多种实际因素影响下的海上地震勘探单枪子波模型。此模型考虑了气泡壁的热传导作用、枪口节流作用、气泡上浮、液体粘度和枪体本身等对气枪子波的影响。相对于Ziolkowski模型,改进模型所模拟的气枪子波主峰值减小,气泡振动衰减加快,与实测子波吻合性较好。实验分析表明：（1）枪口节流作用控制着气枪脉冲峰值振幅的大小,（2）上浮过程中气泡周围静水压力值减小,气泡振动的周期随之改变,（3）热传导作用和流体粘度是引起气泡振动衰减的主要因素。