Characteristics of Radium Desorption from Sediments in the Salt Water Environment

海底沉积物向上覆水体扩散的镭是海洋水体中镭同位素的重要来源之一。为了研究沉积物中镭同位素的解吸和扩散特点,进行了不同盐度和不同粒度条件下224rA和226rA解吸的模拟实验,并通过多个时间段的沉积物培养实验获取224rA和226rA的扩散通量。实验结果表明:随着水体盐度增大,沉积物中224rA、226rA的解吸量随之增加,在盐度为25时,解吸量基本达到最大值;在同一咸水环境条件下,4个粒级(2000~1000μM、1000~500μM、500~250μM、250~125μM)的沉积物的224rA、226rA解吸量比较接近,粒级>2000μM的224rA、226rA解吸量略高于上述4个粒级,而粒级<125μM的224rA、226rA解吸量远大于上述5个粒级;胶州湾沉积物中224rA和226rA的平均扩散通量分别为0.85 bQ·M–2·d–1和0.022 bQ·M–2·d–1。Radium diffusion from sediments to overlying water is one of the important sources of radium isotopes in ocean water.A series of laboratory desorption/diffusion experiments were conducted to help elucidate the characteristics of sediments on 224 Ra and 226 Ra desorption and diffusion,which included 1) 224 Ra and 226 Ra desorption from sediments in water of different salinities,2) 224 Ra and 226 Ra desorption from sediments of different grain sizes in water of the same salinity,3) 224 Ra and 226 Ra diffusive fluxes by observing Ra enrichment with time in the overlying water of incubated sediments.The experimental results show that there is an increase in the amount of 224 Ra and 226 Ra with the increase of salinity from 5 to 30,and Ra desorption is strongest at the salinity of 25.Under the same salt water condition,224 Ra and 226 Ra desorption activities of the four grain sizes(2000~1000 μm,1000~500 μm,500~250 μm and 250~125 μm) of sediments are very close to each other.When the grain sizes of sediments are larger than 2000μm,the 224 Ra and 226 Ra desorption activities are slightly higher than those of the sediments of the above-mentioned four grain sizes.When the grain sizes of sediments are less than 125 μm,the 224 Ra and 226 Ra desorption activities are much larger than those of the above-mentioned five grain sizes.The average diffusive fluxes of 224 Ra and 226 Ra of sediments from Jiaozhou Bay are 0.85 Bq·m-2·d-1 and 0.022 Bq·m-2·d-1,respectively.国家自然科学基金项目(编号:41072174)资

Real-space imaging with pattern recognition of a ligand-protected Ag374 nanocluster at sub-molecular resolution

厦门大学化学化工学院郑南峰教授团队长期致力于研究固体功能材料的表界面化学行为，在分子水平上实现对固体功能材料的化学性能的调控与优化。得益于固体表面物理化学国家重点实验室的多学科合作以及能源材料化学协同创新中心的多单位优势互补，郑南峰教授课题组通过与校内外多个课题组的密切合作，近期在功能材料的可控制备、复杂表界面结构的高分辨表征和表界面过程分子机制的深入理解等方面取得系列重要进展，相关成果近期均在Nature Communications发表。 针对纳米颗粒表面配体难被高分辨直接成像的特点，与厦门大学郑兰荪、谢兆雄等教授以及中科院大连化物所杨学明研究员、马志博副研究员和芬兰于韦斯屈莱大学HannuHäkkinen教授等多个团队紧密合作，在利用扫描隧道显微镜表征金属纳米团簇的表面配体层结构方面取得重要进展。以原子结构精确的 Ag374纳米团簇为研究对象，利用超高真空扫描隧道显微镜分别在液氦及液氮温度下获得了单个团簇亚分子高分辨率的拓扑图像。【Abstract】High-resolution real-space imaging of nanoparticle surfaces is desirable for better understanding of surface composition and morphology, molecular interactions at the surface, and nanoparticle chemical functionality in its environment. However, achieving molecular or sub-molecular resolution has proven to be very challenging, due to highly curved nanoparticle surfaces and often insufficient knowledge of the monolayer composition. Here, we demonstrate sub-molecular resolution in scanning tunneling microscopy imaging of thiol monolayer of a 5 nm nanoparticle Ag374 protected by tert-butyl benzene thiol. The experimental data is confirmed by comparisons through a pattern recognition algorithm to simulated topography images from density functional theory using the known total structure of the Ag374 nanocluster. Our work demonstrates a working methodology for investigations of structure and composition of organic monolayers on curved nanoparticle surfaces, which helps designing functionalities for nanoparticle-based applications.The experimental work done in Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, was supported both by Xiamen University (The National Key R&D Program of China grant 2017YFA0207302, National Natural Science Foundation of China, grant 21731005, 21420102001 and 21721001 the National Key R&D Program of China grant 2017YFA0207302) and DICP (National Natural Science Foundation of China grant 21688102, the Strategic Priority Research Program of Chinese Academy of Science, grant XDB17000000, the National Key Research and Development Program of the MOST of China, grant 2016YFA0200603 and the open fund of the state key laboratory of molecular reaction dynamics in DICP, CAS, grant SKLMRD-K201707). Q.Z. thanks Dr. Huayan Yang for providing the samples for STM imaging. S.M. and H.H. thank T. Kärkkäinen and P. Nieminen for discussions on pattern recognition algorithms. The theoretical and computational work in the University of Jyväskylä was funded by the Academy of Finland (grants 294217, 315549, AIPSE program, and H.H.’s Academy Professorship). H.H. acknowledges the support from China’s National Innovation and Intelligence Introduction Base visitor program. S.K. thanks the Vilho, Yrjö, and Kalle Väisälä Foundation for the grant for doctoral studies. The DFT simulations were done at the Finnish national supercomputing center CSC and at the Barcelona Supercomputing Center (PRACE project “NANOMETALS”). 研究工作得到了科技部、国家自然科学基金委和教育部，中科院先导项目，国家重点研发计划，分子反应动力学国家重点实验室开放课题基金等项目的资助

基于3dmine软件的煤炭资源数据建模与分析

三维地质模型可以为不同领域的工程设计、施工及决策提供帮助。以山东古城煤矿3煤为研究对象,基于3DMine软件对目标煤层进行三维地质建模、储量计算和煤质分布规律分析。首先结合已有地质资料和钻孔数据建立钻孔数据库,构建了插入断层面的3煤顶底板表面模型;然后将煤层模型块体化,采用距离幂次反比法对块体属性模型进行插值,并据此计算了煤层可采储量、分析目标煤层煤质分布情况。结果表明,使用断层模型控制下的煤层三维表面模型能够直观反映煤层和构造的实际空间形态,在考虑全矿性损失影响后,依据煤层三维块体属性模型计算所得的可采储量结果更具实际参考意义,结合三维煤层模型分析煤质与煤层埋深的关系表明,研究区从北西到南东,随着煤层埋藏深度逐渐增加,煤的深成变质作用逐渐加深,灰分、硫分、挥发分随之降低,发热量和黏结指数随之升高

WATER APPARENT AGES AND SUBMARINE GROUNDWATER DISCHARGE of JIAOZHOU BAY INDICATED BY RADIUM ISOTOPE TRACERS

为评价胶州湾水体表观年龄和地下水入海通量,2011年9—10月在胶州湾地区分别采集地下水、河水和海水样品,对水样的224rA和226rA活度进行测量。基于224rA和226rA半衰期的差异,运用224rA与226rA的活度比值计算了胶州湾水体表观年龄;采用三端元混合模型计算了胶州湾海水中地下水、河水与湾外海水的混合比例;在水体表观年龄和混合比例的基础上,计算了地下水入海通量。结果表明:研究期间胶州湾水体表观年龄分布范围为3.2—39.4d,平均值为14.7d,呈现从湾顶到湾口年龄逐渐增大的趋势,地下水的平均混合比例是11.0%,地下水的入海通量为7.29x106M3/d,海底地下水排泄速率为3.8CM/d。To estimate water apparent ages and submarine groundwater discharge(SGD) of Jiaozhou Bay, Shandong, China, water samples were collected from groundwater, river water, and seawater around the bay in September to October, 2011.The activities of 224 Ra and 226 Ra in water samples were measured in laboratory by emanation methods.Based on different half-times of 224 Ra and 226 Ra, water apparent ages in Jiaozhou Bay were calculated using the activity ratio of 224 Ra to 226 Ra.A three end-member mixing model was used to estimate the relative contributions of groundwater, river water, and open ocean seawater to Jiaozhou Bay.With the water apparent ages and the contributions of each sources, the groundwater input to the bay was calculated.The results show that the water apparent ages ranged from 3.2d to 39.4d, average 14.7d.The ages in the bay head were relatively younger than those in the bay mouth.The average mixing ratio of groundwater was about 11.0%, and groundwater input to the Jiaozhou Bay was 7.29×106m3/d; SGD flow rate was 3.8cm/d.国家自然科学基金项目;1072174

Distribution characteristics of radium isotopes and their influence factors in the water of Jiaozhou Bay area

2012年4-5月以胶州湾地区为研究地点,分析和研究了该地区地下水、河水、海水中224rA和226rA的分布特征及其影响因素。结果表明,232TH和238u浓度较高的花岗岩地区地下水和河水中224rA和226rA的活度均比其他地区高;受到海水混合的影响,沿岸地区地下水和河水由于水体盐度升高,224rA和226rA从固体颗粒的解吸量增加,从而导致活度较高;受河流输入(溶解态和悬浮颗粒解吸)以及海底地下水排泄(SubMArInE grOundWATEr dISCHArgE,Sgd)影响,胶州湾近岸海水224rA活度相对较高,之后224rA自身衰变以及外海水的混合稀释,使224rA活度分布呈现随着离岸距离增加活度逐渐降低的特点;而226rA活度在胶州湾内则保持一个较高水平,只出现个别226rA低值分布区,主要原因是外海水与陆源淡水的226rA活度较为接近且226rA半衰期较长。Background: The interaction between continental and oceanic process is much intense in coastal region.The terrestrial freshwater mixes with seawater here which leads to the chemical constituents in water undergo rapid change.Purpose: The aim is to analyze and study the distribution characteristics of 224Ra and 226Ra and their influence factors in the water of Jiaozhou Bay area.Methods: The water samples of 224Ra and 226Ra were collected from groundwater, river water and seawater around the Jiaozhou Bay from April to May, 2012.In the laboratory, the activities of 224Ra absorbed on the Mn-fiber were measured through the continuous emanation method.Finally, the Mn-fiber was sealed for more than 7 days, and the activities of 226Ra absorbed on the Mn-fiber were measured through the direct emanation method.Results: The results show that the activities of 224Ra and 226Ra in groundwater and river water are much higher in the granitic area which has higher concentration of 232Th and 238U.Because of mixing with seawater, the salinity of groundwater and river water in coastal region rises which leads to the increasing amounts of 224Ra and 226Ra desorbed from the particles, resulting in higher activities of 224Ra and 226Ra in coastal region.Affected by the input of river(dissolved and desorbed from suspended particles) and submarine groundwater discharge(SGD), the activities of 224Ra and 226Ra are relatively higher in nearshore seawater, then with the decay of 224Ra and mixing dilution effect of the offshore seawater, the activities of 224Ra gradually decrease from nearshore region to the open ocean.The activities of 226Ra in the seawater of Jiaozhou Bay remain high-level values, and there are only a few zones of low 226Ra activities.The main reasons are that the activities of 226Ra from terrestrial freshwater are close to those from offshore seawater and the half-life of 226Ra is very long.Conclusion: The activities of 224Ra and 226Ra in groundwater relate to the rock around Jiaozhou Bay and the water salinity.In addition to rock and water salinity, the activities of 224Ra and 226Ra in river water are also concerned with human activities and the process of groundwater recharge.The activities of 224Ra and 226Ra in seawater depend on the sources and sinks of radium isotopes.国家自然科学基金项目(No.41072174)资

LP-MOVPE生长的低阈值1.3μm InGaAsP/InP 压、张应变交替 MQW 激光器特性

国内首次报道了LP-MOVPE法生长高质量的高、张应变交替InGaAsP多量子阱结构的研制过程及其材料的高精度X-ray双晶摇摆衍射曲线和荧光光谱特性表征。经过双腔面镀增透射膜后，其TE模与TM模自发发射谱光强差为3dBm，呈现偏振补偿特性