Dynamic Evolution of Regional Ecological Services Based on TM Remote Sensing

针对传统评估区域生态系统服务价值空间异质性的问题,本研究将TM遥感影像与价值评估法相结合,测算出针对研究区域的当量因子表,并建立了只需遥感影像数据即可快速并较为精准地动态计算区域生态系统服务价值的多元回归模型。文章以北京市永定河、厦门市和青海省不同尺度为例,对该方法评估区域生态系统服务价值的可行性和准确性进行了讨论,以期为生态综合管理提供定量化参考依据。This paper discussed the dynamic evaluating of regional ecological services with remote sensing technique,based on the comprehensive analysis the character of indexes method and currently equivalent method applying to regional ecological services.With the established method in the literature,it discussed the practical possibility for evaluation the temporal and special regional ecological services in Yongding River,Xiamen and Qinghai province.Compared with the traditional static indexes evaluation,our method discussed the possibility of dynamically evolutional evaluation,in order to provide reference of ecosystem management.北京市科学技术委员会“永定河生态修复目标体系研究”(D090409004009003);北京市生态学重点学科项

类泛素蛋白及其中文命名

泛素家族包括泛素及类泛素蛋白,约20种成员蛋白.近年来,泛素家族领域取得了迅猛发展,并已与生物学及医学研究的各个领域相互交叉.泛素家族介导的蛋白质降解和细胞自噬机制的发现分别于2004和2016年获得诺贝尔奖.但是,类泛素蛋白并没有统一规范的中文译名. 2018年4月9日在苏州召开的《泛素家族介导的蛋白质降解和细胞自噬》专著的编委会上,部分作者讨论了类泛素蛋白的中文命名问题,并在随后的\"泛素家族、自噬与疾病\"(Ubiquitinfamily,autophagy anddiseases)苏州会议上提出了类泛素蛋白中文翻译草案,此草案在参加该会议的国内学者及海外华人学者间取得了高度共识.冷泉港亚洲\"泛素家族、自噬与疾病\"苏州会议是由美国冷泉港实验室主办、两年一度、面向全球的英文会议.该会议在海内外华人学者中具有广泛影响,因此,参会华人学者的意见具有一定的代表性.本文介绍了10个类别的类泛素蛋白的中文命名,系统总结了它们的结构特点,并比较了参与各种类泛素化修饰的酶和它们的生物学功能.文章由45名从事该领域研究的专家合作撰写,其中包括中国工程院院士1名,相关学者4名,长江学者3名,国家杰出青年科学基金获得者18名和美国知名高校华人教授4名.他们绝大多数是参加编写即将由科学出版社出版的专著《泛素家族介导的蛋白质降解和细胞自噬》的专家

Hydrodynamic Simulation of Column Flotation for Coal Separation

煤炭分选是低品位煤炭资源提质利用的重要环节，开展微细粒煤柱浮选工艺及设备的研究，是选煤技术发展的一个重要方向。浮选柱流体力学是浮选柱设计放大和优化操作的理论基础，是柱浮选发展的重要研究方向。利用数值模拟方法开展浮选柱流体力学特性的系统研究，能够加深对浮选过程中各相间相互作用规律的理解，为系统揭示浮选柱的放大规律，实现浮选过程强化和浮选柱的优化设计提供有力的理论支持。本论文致力于利用数值模拟技术指导浮选柱设计放大与优化操作，围绕浮选柱局部流体力学特性分布规律开展研究。论文的主要研究内容和结论如下： 1、针对浮选柱体系气含率高、流型复杂的特点，就气液两相湍流模型和相间作用力模型进行分析比较，最后选择Eulerian多相流模型结合Realizable k-ε湍流模型以及修正的Tomiyama曳力系数模型，并考虑升力和虚拟质量力的影响，对传统鼓泡浮选柱内气液两相流进行数值模拟。通过将流体动力学模拟结果与文献报道的实验数据进行对比，验证了所选模型模拟浮选柱体系的可靠性。 2、基于商业CFD软件Fluent，对旋流-静态微泡浮选柱进行气液两相流数值模拟，着重分析了气含率、气液相速度及湍流特性在浮选柱内的分布规律。结论如下： (1) 受旋流作用影响，浮选柱柱体中心气含率较高，气泡有向柱体中心运动的趋势； 随垂直高度增加，旋流作用减弱，气含率分布逐渐趋于均匀。 (2) 气液两相速度（轴向速度、切向速度）分布规律基本相似；切向运动仅存在于旋流分离段，随垂直高度上升，气液相切向运动迅速衰减。 (3) 高湍流区主要分布于旋流分离段，柱浮选段的湍流动能和湍流强度总体较低；原矿矿浆进料引入的不均匀流动增强了柱浮选段的湍动程度，在柱浮选段产生局部高湍流区。 (4) 对矿化管流段的研究表明，管段长度对管段矿化效果影响较大：管段过短，管内湍流得不到充分发展，管内矿化不充分；管段过度延长，管段末端湍流程度减弱，也会影响管段的矿化效果

府谷次烟煤热解的反应分子动力学模拟

深入研究低阶煤的热解行为和热解反应机理对于开发先进的低阶煤转化技术具有重要意义。然而煤热解为高温自由基过程，期间涉及数量众多且相互耦合的化学反应路径并伴有大量自由基中间产物的生成与消耗，反应机理极其复杂。由于缺乏对自由基演化的原位检测手段，使得通过实验从分子层面研究煤热解的微观机理面临诸多困难。基于键级的化学反应力场ReaxFF与分子动力学结合的反应分子动力学方法（ReaxFF MD），可连续描述化学键的断裂与生成，其准确度接近于广泛应用的密度泛函理论，并且可以大幅度降低计算的复杂度，是极具潜力的深入研究煤热解机理的方法。本论文致力于采用ReaxFF MD模拟对府谷次烟煤的热解规律进行深入研究，提出了一种大规模多组分煤模型的构建方法，构建了府谷次烟煤的大规模多组分模型，针对该模型开展了慢速升温与恒温热解过程的ReaxFF MD模拟，获得了利用实验手段和其它计算方法难以得到的煤热解反应机理的认识。本论文还开展了府谷次烟煤的热解-同步辐射真空紫外光电离飞行时间质谱实验，以便从实验角度更好地认识府谷次烟煤的热解过程并为ReaxFF MD模拟结果评价提供参考并与其互为补充。本论文的主要工作与结论如下：基于中国科学技术大学国家同步辐射实验室的固体热解-同步辐射真空紫外光电离飞行时间质谱实验装置，开展了府谷次烟煤的热解实验研究，确定了主要热解产物的质谱峰归属。通过比较不同温度（500、600、700、800℃）条件下主要热解产物的质谱信号获得了主要气体产物和代表性芳香族产物随热解温度的演变规律。实验结果表明：高温有利于低分子烯烃类热解产物的生成；酚羟基的存在和芳香环的增大都会使芳香环的烷基取代基的反应活性增强。提出了一种基于煤样的常规实验表征数据（工业分析与元素分析、13C核磁共振分析和溶剂抽提实验）的大规模多组分煤模型的手动构建方法。该方法兼顾煤模型的结构多样性和构建效率，对煤大分子组分采用平均化的构建策略以快速达到煤模型与煤样的元素组成及主要结构参数的吻合，并通过改变组成煤大分子的结构单元间的连接关系以增加煤模型的结构多样性。该方法同时考虑了分布于煤大分子组分间的游离相小分子化合物以更好地描述煤的两相结构。基于该模型构建方法并结合府谷次烟煤的实验表征数据，构建了其大规模多组分三维模型。该模型总共包含23,898原子，由75个平均化的大分子组分模型和29个游离相小分子化合物组成，其中大分子平均组分包含20种不同的分子结构以描述煤的结构多样性。该多组分模型的元素组成、芳香碳含率及芳香团簇的平均尺寸都与煤样的实验表征数据较为吻合。该模型应用于ReaxFF MD热解模拟可获得合理的产物组成及其演化趋势。应用基于GPU并行的反应分子动力学模拟程序GMD-Reax，对府谷次烟煤的多组分模型开展了慢速升温（300~2500 K, 1 K/ps）条件下的ReaxFF MD热解模拟研究。获得了府谷次烟煤在慢速升温条件下热解过程的三个阶段：煤结构活化阶段（Stage-I）、快速热分解阶段（Stage-II）和缩聚结焦阶段（Stage-III），快速热分解阶段可再分为一次热解阶段（Stage-IIA）和二次热解阶段（Stage-IIB）。重点考察了主要组成元素（碳、氢、氧、氮）在热解产物中的分布与迁移规律，结果表明：碳元素在挥发性产物中的相对含量顺序为重质焦油&gt;轻质焦油&gt;热解气，即碳元素在慢速升温热解过程中逐渐向重质焦油和非挥发性组分中迁移富集；氢元素在慢速升温热解过程中主要向热解气中迁移富集；氧元素在挥发性产物中的相对含量顺序为热解气&gt;轻质焦油&gt;重质焦油，即氧元素在慢速升温热解过程中主要迁移富集到热解气中；氮元素在慢速升温热解的前两个阶段（模拟温度达2000 K前）未表现出明显的迁移倾向，而在缩聚结焦阶段迅速向热解气中迁移富集。应用化学反应分析与可视化软件VARxMD分析慢速升温热解的ReaxFF MD模拟结果，揭示了实验手段或其它计算方法难以直接获得的主要轻质气体产物（CO2、H2O、H2和CH4）的详细生成反应路径。结果表明：府谷次烟煤热解初期CO2、H2O和H2的生成反应都与羧基密切相关，CH4的初始生成反应则与甲氧基紧密关联，因此可以认为羧基和甲氧基等含氧官能团在府谷次烟煤热解初期，尤其是初始活化阶段发挥着至关重要的作用。利用ReaxFF MD在不同温度（1200、1400、1600、1800、2000、2200 K）条件下针对府谷次烟煤多组分模型开展了2000 ps的恒温热解模拟，考察了模拟温度和模拟时间尺度对府谷次烟煤的热解行为和产物产出的影响，获得了府谷煤在不同温度条件下的热解产物演化规律。与文献报道的府谷煤流化床热解实验结果相比，ReaxFF MD恒温模拟显著高估了煤焦油的产出、略微低估了热解气的产出。通过对府谷次烟煤高温较短时间尺度和低温较长时间尺度模拟的热解产物演化趋势的比较发现，1200&ndash;2200 K的模拟温度范围内，将模拟时间从2000 ps缩短为250 ps，则模拟温度需要提升400 K来获得相似的热解产物演化趋势，但会导致煤焦油和热解气产量的高估以及非挥发性产物产量的低估。升温模拟策略和模拟时间尺度对热解产物演化影响的探讨可为今后选择ReaxFF MD模拟策略提供依据。本论文提出的多组分煤模型的快速构建方法是构建可用于ReaxFF MD模拟煤热解的大规模煤模型的可行方法。合理的大规模煤模型结合基于高性能计算的ReaxFF MD模拟可以获得府谷次烟煤热解产物的全景式演化规律，有望扩展至其它低阶煤的热解模拟研究中，从而为更好地利用低阶煤提供理论支持。;Coal pyrolysis refers to the initial reaction step in most coal conversion processes, which plays a significant role in efficient and clean utilization of coal, especially for low-rank coals. Coal pyrolysis is well accepted as a radical driven process that involves myriad coupled reaction pathways with vast free radical intermediates generated. The heterogeneous nature of coal and the complexity of the pyrolysis process have made it very difficult to access the comprehensive mechanisms, even with the state-of-the-art experimental approach. When combined with molecular dynamics (MD), the ReaxFF reactive force filed based on bond order can describe the dynamic evolution of bond breaking and forming smoothly with accuracy close to the widely used Density Functional Theory (DFT) method with very much reduced computational costs.The overall pyrolysis process and the underlying chemical reactions of Fugu subbituminous coal are studied in the thesis by combining large-scale ReaxFF MD simulations and solid pyrolysis experiments with in situ synchrotron vacuum ultraviolet photoionization time-of-flight mass spectrometry (SVUV-PI-TOF-MS). The main results are summarized as the following.The pyrolysis experiments of Fugu subbituminous coal were performed using the solid pyrolysis apparatus with the volatile species detected by SVUV-PI-TOF-MS at the National Synchrotron Radiation Laboratory (NSRL) in Hefei, China. The dynamic profiles of major light gases and aromatic-based tar products with temperature were obtained by comparison of major pyrolyzates at varied temperature conditions (500, 600, 700, and 800 oC). The experimental results reveal that the existence of phenolic hydroxyl groups and enlargement of aromatic nucleus can both promote the reactivity of alkyl substituents in aromatic rings.A strategy was proposed for constructing large and reasonable coal molecular models with multi-components manually based on the limited conventional characterization data of coal samples (proximate and ultimate analysis, 13C NMR, and solvent extraction experiments). Both the structure diversity of macro coal molecules and model construction efficiency were considered in the proposed strategy. Local structure variation and average strategy for elemental composition are combined in the construction of macro coal molecules, which allows for structure diversity and easy match in a multi-component coal model with experimental characterization data of coal samples. Following the proposed strategy, a multi-component molecular model was constructed for Fugu subbituminous coal. The constructed Fugu coal model is a large model containing 23,898 atoms. It consist of 75 macromolecules with 20 varied average structures for structural diversity and 29 varied small compounds to capture the mobile phase. The element composition, aromaticity and averaged aromatic nucleus size of the Fugu coal model constructed are in good agreement with the experimental characterization of Fugu subbituminous coal.Slow heat-up (1 K/ps) and long-time (2000 ps) isothermal simulations were performed using the constructed large Fugu coal model with the GPU-enabled ReaxFF MD code of GMD-Reax to investigate the effects of heating rate and temperature on the coal pyrolysis. The reaction analysis code of VARxMD was used for uncovering the associated reaction mechanism in coal pyrolysis. Analysis of the heat-up ReaxFF MD simulation trajectories shows that Fugu coal pyrolysis process can be divided into three stages: the activation stage of coal structure (Stage-I), the primary pyrolysis (Stage-IIA) and the secondary pyrolysis stage (Stage-IIB), and the recombination dominated stage (Stage-III). The element distribution and migration among pyrolyzates in coal pyrolysis were analyzed. The content of C element in pyrolyzates are ranked as heavy tar &gt; light tar &gt; gas, which indicate that C element migrates to heavy tar and non-volatile molecules. While H element migrate to gas products. The content of O element in pyrolyzates are ranked as gas &gt; light tar &gt; heavy tar. The N element tends to stay in coal molecules that will migrate to gas products at stage-III of high temperature.By taking advantage of VARxMD for reaction analysis for ReaxFF MD simulations, detailed reaction pathways for the early gas product generation of CO2, H2O, H2 and CH4 in the activation and primary pyrolysis stages of Fugu subbituminous coal are revealed on the basis of heat-up simulations, which is hardly accessible experimentally or by other computational approach. It can be concluded that the gas product generation of CO2, H2O, H2 and CH4 in the activation and primary pyrolysis stages are closely associated with carboxyl and methoxyl groups, indicating the critical role of oxygen-containing groups in the initialization of subbituminous coal pyrolysis.Furthermore, the effects of elevated simulation temperature and simulation time on pyrolyzate profiles and yields were first investigated by the long time (2000 ps) isothermal ReaxFF MD simulations. Compared with reported experiments of fluidized bed pyrolysis, the coal tar yield is over-predicted, while the gas yield is slightly under-estimated. By comparing the weight profiles between the short and long duration time at high and low temperature conditions, it is found that to shorten the simulation time from 2000 ps to 250 ps, an increase of 400 K in average for simulation temperature is needed in range of 1200&ndash;2200 K to get similar pyrolyzate profiles that will result in the over-prediction for the yields of gas and tar, as well as under-prediction for the non-volatile yield. What obtained can be used in refining simulation strategy for coal pyrolysis study.The proposed strategy for fast constructing large and reasonable coal models manually with varied chemical structures is practical for construction of large multicomponent molecular models for coal pyrolysis study with ReaxFF MD. Combining with the reasonable and large coal molecular model, the ReaxFF MD simulation approach is useful for getting an overall scenario of coal pyrolysis and deeper insight into the complex pyrolytic reaction of Fugu subbituminous coal. The method can be applied in studying pyrolysis reaction mechanism of other low rank coals for their better utilization.Coal pyrolysis refers to the initial reaction step in most coal conversion processes, which plays a significant role in efficient and clean coal utilization, especially for low-rank coals.&nbsp;</p

石墨烯复合染料敏化太阳能电池的光阳极及其制备方法

本发明公开了石墨烯复合染料敏化太阳能电池的光阳极及其制备方法。本发明的光阳极的特点是石墨烯排列在透明导电基底表面，并且石墨烯的片状面与该透明导电基底表面之间的夹角不等于0&deg;与180&deg;，该夹角最优选为90&deg;。与现有技术相比，本发明的光阳极不仅可以将光生电子更快速的转移到外电路、尽可能减少电子与电解质的复合，还可以减少石墨烯对光的吸收面积、提高电池的光利用率，因此本发明的光阳极可以提高光电能量转换效率；相应地，采用本发明的光阳极的染料敏化太阳能电池相对于未复合石墨烯的染料敏化太阳能电池以及现有的石墨烯复合的染料敏化太阳能电池，光电能量转换效率分别提高了44.7％和15.8％

对甲基苯酚高温热解的ReaxFF-MD模拟

甲基苯酚是煤热解产物之一,其高温热解反应可能是影响煤热解过程二次反应及最终热解产物性质的重要因素。本文利用ReaxFF MD方法[1]就对甲基苯酚热解机理进行研究,模型体系由1000个对甲酚分子构成。考察了主要热解产物的生成顺序及产物分布随温度的演变规律,结果表明苯、甲苯等芳香产物随温度升高先增多后减少,而氢气、甲烷等小分子气体随温度单调增加。本文还基于ReaxFF可视化分析工具VARxMD[2]分析获得了初始反应机理及主要产物的生成路径