风驱粗糙海面背景下海雾对可见和红外光多次散射特性研究

通过测量空间辐射反演海雾气溶胶的微观特性是一种重要的遥感方法,但是海雾对辐射的反射会受到海面背景的影响。该工作研究了海雾与海面的耦合多次散射。利用Mie理论研究了海雾气溶胶的单次散射特性,利用辐射传输理论研究太阳光在无下垫面海雾中传输多次散射特性;在基尔霍夫近似下研究了风驱粗糙海面的散射特性,并考虑了海面的遮蔽效应,得到了风驱海面随风速的反射函数。根据累加法研究了海雾和海面的耦合散射,计算结果表明海雾在有粗糙海面作为背景的情况下,其整体反射有较大增强。     

最小冰聚体结构单元模型及其对水性质影响的量化分析

水的一些奇特性质主要源于水分子之间存在的氢键, 但在分子尺度上的氢键结构和数据仍是目前研究和争论的焦点. 统计分析了目前文献中普遍采用的水分子和氢键结构数据, 并在此基础上应用AutoCAD图形软件模拟出(H2O)10结构的最小冰聚体结构单元(Minimum Ice Structural Unit, MISU)模型, 以及由MISU聚合而成的冰晶体三维模型. 根据MISU模型, 可以计算得到冰在0 ℃融化为水、水由0 ℃加热至100 ℃、水在100 ℃汽化为水蒸气的三相转化过程中分别需要吸收5.86, 4.40和24.94 kJ•mol－1的能量以断裂16.7%, 12.5%和70.8%的氢键. 如若不考虑氢键的影响, 那么计算得到水的融化热和汽化热分别为0.15和15.73 kJ•mol－1, 与VIA族氢化物H2S, H2Se, H2Te的融化热和汽化热基本呈线性关系. 另外, 由MISU模型计算得到冰在0 ℃融化为水时, 密度由923.17 kg•m－3增至999.89 kg•m－3, 亦与实际测量数据基本一致.     

Impact of ice particle shape on short-wave radiative forcing: A case study for an arctic ice cloud

We used four different non-spherical particle models to compute optical properties of an arctic ice cloud and to simulate corresponding cloud radiative forcings and fluxes. One important finding is that differences in cloud forcing, downward flux at the surface, and absorbed flux in the atmosphere resulting from the use of the four different ice cloud particle models are comparable to differences in these quantities resulting from changing the surface albedo from 0.4 to 0.8, or by varying the ice water content (IWC) by a factor of 2. These findings show that the use of a suitable non-spherical ice cloud particle model is very important for a realistic assessment of the radiative impact of arctic ice clouds. The differences in radiative broadband fluxes predicted by the four different particle models were found to be caused mainly by differences in the optical depth and the asymmetry parameter. These two parameters were found to have nearly the same impact on the predicted cloud forcing. Computations were performed first by assuming a given vertical profile of the particle number density, then by assuming a given profile of the IWC. In both cases, the differences between the cloud radiative forcings computed with the four different non-spherical particle models were found to be of comparable magnitude. This finding shows that precise knowledge of ice particle number density or particle mass is not sufficient for accurate prediction of ice cloud radiative forcing. It is equally important to employ a non-spherical shape model that accurately reproduces the ice particle's dimension-to-volume ratio and its asymmetry parameter. The hexagonal column/plate model with air-bubble inclusions seems to offer the highest degree of flexibility.     

长柱状气溶胶粒子的光散射特性

以中纬度卷云中常见的长柱状冰晶为例,利用长柱状粒子光散射理论,探讨了入射光为线偏振时,电矢量平行和垂直于入射面情况下,单个长柱状粒子的散射光强度分布和偏振特性随入射角、尺度参数与偏振态的转化关系:随着入射角的增大,散射强度、偏振总体趋于对称且数值振荡频率降低,散射强度总体减小,偏振的改变程度总体增大;随着尺度参数的增大,散射强度、偏振的数值振荡频率增大,散射强度数值振荡峰的幅度整体减小,电矢量平行于粒子长轴时主偏振的数量、强度和位置皆有变迁,电矢量垂直于粒子长轴时前后主偏振位置相对固定;随着偏振度的减小,散射强度、偏振趋向于一致,两者的数值改变程度减小,当偏振度减小到0时,散射强度、偏振变得完全相同。选取火山尘埃和烟灰与冰晶对比,阐述了粒子散射光的强度分布和偏振特性随折射率的变化规律:折射率虚部不改变散射强度的整体趋势,但使散射强度和偏振的振荡峰幅度增大,当其数值较大时,使得偏振的数值振荡峰覆盖范围拓宽。     

海域岛礁桥梁地基岩体质量分级体系研究

跨海大桥由于受地形限制,桥基只能布设在单薄的海域岛礁上,而岛礁岩体质量及其边坡稳定将控制桥基型式及埋深。结合在建舟山大陆连岛工程西堠门大桥桥基所在的老虎山岛礁,针对其大跨度、高塔柱桥梁地基赋存的地质环境条件,综合考虑不同部位（即水上、水下及潮间带三个不同位置）,提出以岩石力学性质、岩体结构类型、结构面发育特征（尤其是软弱结构面控制）、风化状况、地下水（受海水频繁潮涨潮落影响）等分级控制因素,并分别相应采用岩石单轴饱和抗压强度Rs、岩石质量指标RQD、岩体完整性系数Kv、风化程度系数KY及地下水影响修正系数U对上述分级控制因素进行量化,建立了反映海域岛礁岩体总体质量综合指数Z=Rs×RQD×Kv×KY+U,并相应得出不同级别岩体质量分级体系。     

水下成组药包爆炸作用下冰盖动态响应数值模拟

利用大型有限元软件ANSYS/LS-DYNA建立了成组药包水下爆炸冰盖动态响应模型,通过数值计算,得到了冲击波峰值压力变化规律,峰值压力与理论计算结果基本吻合。本文分析了冰盖在成组药包水下爆炸冲击载荷下的应力分布及垂直位移响应特征。结果表明,冰盖迎爆面为压缩破坏,背爆面为拉伸破坏,两者数值均十分接近,其中迎爆面最大压力值可达18.12MPa,冰盖近爆炸点最大垂直位移为1.211cm,两药包连线中点最小位移为0.15cm,达到脆性冰盖形成贯通裂隙的基本条件,从而确定了冰盖在水下成组药包大间距布设条件下,其动态破坏形式是以产生裂隙为主要特征。     

一种深海中温菌胞外多糖水溶液的流动行为

研究了一种深海中温菌Wangia profunda(SM-A87)胞外多糖(EPS)稀溶液在德国Haake RS75流变仪Z41 DIN同轴圆筒转子系统中的剪切流动行为, 考察了溶液浓度、 温度、 pH值及NaCl浓度对雷诺数(Re)和临界雷诺数(Re_c)的影响. 结果表明, 随着溶液浓度的增大, Re逐渐减小而Re_c逐渐增大; 随着温度的升高和NaCl浓度的增大, Re逐渐增高而Re_c逐渐降低; 在pH=3~12内随着pH值的增加, Re和Re_c开始基本保持不变, 当pH>7后Re逐渐增加而Re_c逐渐降低. Re_c与温度的关系符合Arrhenius-like方程, 与体系黏度间存在幂率关系.     

Numerical solution of the problem of motion of a load on a cracked ice sheet

A mathematical model is constructed for the motion of a load on a cracked ice sheet. Examples of calculation of ice deflections are given, and the calculation results are analyzed. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 151–156, May–June, 2008.     

可燃"冰"与包合物

可燃"冰"是一种沉睡海底和高寒冻土地带待开发的能源.它储存量大,含能量高,是甲烷类中性分子生成的气体水合物,是一类广泛存在的包合物.这种类型包合物的极限化学式为8X@46H2O.本文就可燃"冰"的发现史、结构特点等辐射到的相关知识做一简单介绍.     

Ethylenediamine in the voltammetric determination of copper in sea water at a rotating mercury film electrode

The use of ethylenediamine in the voltammetric study of copper in natural sea water was evaluated for applicability with rotating thin mercury film electrodes. It was shown that this method increases the analytical sensitivity for copper at such electrodes by at least a factor of 4, and improves the detection of pH 8 labile copper.