177 research outputs found

    Theoretical Study of Photo-electrochemical Reaction on Metal Nanostructure Surfaces

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    等离激元纳米结构可以高效地利用太阳光能并将其用于化学过程,等离激元增强的催化以及光催化反应成为近年来的一个研究热点。在一定激发光波长照射,金或者银纳米粒子表面的自由电子在外界光电场的扰动下发生集体振荡。当入射光电场的频率与金属纳米结构电子振荡的固有频率一致时就会产生共振现象,称为表面等离激元共振。表面等离激元共振对表面化学具有多种促进作用,得益于表面等离激元共振的独特性质,等离激元增强表面催化反应有望成为一种高效的太阳能转化途径。 尽管等离激元增强表面催化反应以及在一系列反应体系中得到证实,然而其反应的基本物理图像仍然不是非常清楚。表面增强拉曼光谱研究表明芳香胺以及硝基化合物在等离激元纳米结...Plasmon-enhanced photocatalytic/catalytic reactions have become a very interesting and active direction of research due to the capability of plasmonic nanostructure for high-efficiently harvesting and utilizing solar energy into chemical processes. When gold or silver nanoparticles absorb visible laser irradiation of a specific wavelength, it triggers electrons in the metal nanoparticles to oscill...学位:理学博士院系专业:化学化工学院_物理化学(含化学物理)学号:2052010015368

    Surface-enhanced Raman Spectroscopy and Plasmon-Assisted Photocatalysis of p-Aminothiophenol

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    对氨基苯硫酚(PATP)是表面增强拉曼光谱(SErS)研究中最重要的探针分子之一.PATP吸附体系具有非常特征且异常强的SErS信号,但人们对其SErS信号的理解仍存在较大争议.本文结合文献,总结了我们为了理解PATP分子异常的SErS光谱所开展的系统的理论和实验工作.首先介绍PATP的SErS增强机理方面开展的理论工作,研究表明PATP分子的异常SErS信号不是来自PATP分子本身,而是来自其表面催化偶联反应产物二巯基偶氮苯(dMAb).通过实验和dMAb合成两个方面,验证了dMAb是异常SErS信号的根源.其次总结了各种实验条件对PATP转化为dMAb的影响,并从实验和理论两个角度探讨PATP的表面催化偶联反应机理.最后,通过对PATP体系的SErS和等离激元增强化学反应的总结,展望表面等离激元增强化学反应的未来发展方向.p-Aminothiophenol(PATP) is one of the most important probe molecules in surface-enhanced Raman spectroscopy(SERS).Adsorbed PATP exhibits very unique and abnormally intense SERS signals.However, the understanding toward the abnormal SERS signals is still in debate.In this review, we overview our theoretical and experimental studies to understand the abnormal SERS of PATP.We first introduce the theoretical investigation on the SERS enhancement mechanism of PATP.The theoretical study shows that the abnormal SERS signals of PATP are not from PATP itself but arise from its surface catalytic coupling product p,p'-dimercaptoazobenzene(DMAB).The assumption is supported by carefully designed experiments of PATP and the SERS signal of the synthesized DMAB molecule.Then, we summarize the experimental factors that influence the photochemical conversion of PATP to DMAB on the surfaces of metal nanostructures.We then explore the reaction mechanisms for the surface catalytic coupling reaction of PATP in both experimental and theoretical aspects.Finally, we proposed the further direction of surface plasmon enhanced chemical reaction on the basis of our systematically studies of SERS and plasmon photocatalysis of PATP

    强制医保制度下无保险人群的健康状况研究

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    因为就业单位不缴或欠缴医疗保险费而被迫无法纳入医疗保险体系的城镇职工在本文中被称为“医保夹心层”。据估算,我国目前存在上千万的医保夹心层人群。本文利用国务院关于城镇居民基本医疗保险试点评估调查2007-2009年的跟踪调查微观数据,研究了医保夹心层的健康及其医疗服务利用情况。我们发现,在控制了个人特征、就业状况、保险状态以及家庭经济状况后,医保夹心层职工的健康状况较差;其无保险状态会直接影响医疗服务利用,表现为医保夹心层更少接受住院服务(但在门诊服务方面没有差别),但一旦住院,夹心层住院花费及其负担都会更重;其次,医疗保险状态还会影响健康意识,表现为夹心层人群在了解医疗保健知识、定期身体健康检查方面缺乏积极性。本文发表在《经济研究》2013年第7期,118-131

    Reviews on Ecosystem Services Valuation and GIS-Based Mapping

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    生态系统服务价值评估是当前生态经济学领域的研究热点,为解决生态系统对人类的重要性提供了量化参考。文章论述了国内外生态系统服务价值的评估方法,分别从静态评估、动态评估和gIS技术应用三大方面进行了归纳分析,提出今后应重点关注生态系统服务价值的时空动态模型开发、评价指标体系与评价方法的标准化制订和生态系统综合管理与应用等方面的研究。Ecosystem services valuation has become one of the hotspots in the field of ecological economics,and provides quantitative evidence concerning the importance of the ecosystem for human-beings.In this paper,we first discussed ESV method in static,dynamic and GIS based respectively.We pointed out that scientific community should focus on several topics in the near future to deepen the understanding of the values of ecosystems.These topics include the development of spatially and temporarily explicit dynamic valuation models,standardization of valuation methods and payment for ES and meeting the requirements of regional ecosystem management and decision making.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

    Development of interleukin-21 as a therapeutic drug

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    白细胞介素21; (IL-21)是一种具有多效免疫调节活性的细胞因子,参与先天性免疫反应和适应性免疫反应的多个环节,与自身免疫性疾病、肿瘤、病毒感染等疾病的发病过; 程相关。研究表明,在动物模型中通过增强或抑制IL-21的生物学功能对多种疾病具有治疗意义,多项以重组人IL-21为受试药物的临床试验已经开展。本; 文就IL-21的生物学功能,以及IL-21作为生化药物在临床治疗中的研究进展和应用前景进行阐述。Interleukin-21 (IL-21) is a cytokine with broad pleiotropic actions that; plays an important role in both innate and adaptive immune responses.; IL-21 participates in pathogenesis processes of many diseases, such as; autoimmune disease, tumor, virus infections and so on. Enhancing or; inhibiting the activity of IL-21 has shown to have certain therapeutic; effects in animal models of a wide range of diseases. Various clinical; trials using recombinant human IL-21 as drug candidates are on-going; towards the development of IL-21 as a therapeutic drug. This article; reviewed the biological function and research progress and application; prospect of IL-21 as a biochemical drug in clinical treatment

    镓在抗菌方面的研究进展

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    抗生素发现\"黄金时代\"的结束以及日趋严重的抗生素耐药性问题给我们留下一个戏剧性的、缺乏新型药物来防治耐药病原体感染的难题。这使得从现有非抗生素药物中筛查抗菌活性药物成为一种新尝试。近期研究表明:美国食品药品监督管理局(FDA)批准的、本来用于治疗高血钙的药物硝酸镓具有良好的抗菌活性。不同于其他抗生素,镓的药理性质依靠化学拟态,它可以在目标酶分子中取代铁,从而干扰、扰乱细菌含铁蛋白的功能及细菌代谢,无论是在体外实验还是在体内实验中,镓对多种病原体,包括多重耐药病原体都表现出杀菌活性。因此一些含镓制剂有望被开发成有潜力的非传统抗菌药物,帮助治疗多重耐药细菌感染。国家自然科学基金(No.81673242、No.81473251、No.31741006、No.31370166和No.81301474);;福建省自然科学基金(No.2014J01139和No.2015J01345);;厦门大学校长基金(No.20720160060

    Vibrational Spectroscopy Criteria to Determine α-Pyridyl Adsorbed on Transition Metal Surfaces

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    Corresponding author. Email: [email protected]; Tel: +86-592-2189023[中文摘要]基于簇模型采用密度泛函理论在B3LYP/6-311+G**/LANL2DZ(metal)基组水平上计算了吡啶及α-吡啶基吸附于Pt、Pd、Rh、Ni四种金属表面的红外和拉曼光谱.通过详细地分析和比较计算结果与文献报道的实验谱图,提出了以N端吸附的吡啶分子和α-吡啶基这两种表面物种各自存在的谱学判据.计算结果表明在以上四种金属表面,α-吡啶基的拉曼活性比吡啶的小,而特征谱峰的红外强度与吡啶相当.该结果表明红外光谱是检测金属表面α-吡啶基的有效手段,也解释了采用表面增强拉曼光谱和红外光谱研究吡啶吸附在金属表面得出不同结构的原因.[英文摘要]Density functional theory calculations at the B3LYP/6-311+G**/LANL2DZ(metal) level were used to predict the infrared (IR) and Raman spectra for pyridine and α-pyridyl upon interaction with platinum (Pt), palladium (Pd), rhodium (Rh), and nickel (Ni) clusters. After carefully comparing the simulated IR and Raman spectra with the corresponding experimental spectra from literature, the characteristic frequencies for the metal surface adsorbed pyridine and α-pyridyl were determined. Our results show that on these metal surfaces α-pyridyl has a far lower Raman activity compared with pyridine, but their characteristic frequencies have comparable IR intensities. This is the reason why different adsorption configurations are proposed for the IR and the surface-enhanced Raman spectra (SERS). Our results indicate that IR spectroscopy is an effective tool to detect α-pyridyl adsorbed on metal surface.国家自然科学基金(20973143,91027009);国家重点基础研究发展规划(973)(2007CB815303,2009CB930703); 厦门大学(2010121020);国家科学人才培养基金(J1030415)资助项

    Study on production of liquid hydrocarbon fuels from sorbitol and mannitol

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    在温和条件下研究了氢碘酸还原生物质基多元醇制备液体燃料的过程,使用气相色谱质谱仪(GC-MS)和红外光谱仪(FT-IR)分析了产物组成。结果表明,山梨醇和甘露醇为原料制备的液体产物中主要成分是C_(12)H_(16)、C_(12)H_(18)、C_(12)H_(20)、C_(12)H_(22)和C_(18)H_(26)等烃类物质。通过与碱的醇溶液反应将副产物碘代烷转化为烃,经旋转蒸发和减压蒸馏获得纯净的高碳烃产品。山梨醇、甘露醇以及二者混合物制备出的高碳烃的产率分别是81.1%、73.2%和77.3%。本研究获得的高碳烃产品是一种有前景的液体燃料,其含水量为0.1%,密度为0.83~0.84 g·mL~(-1),含氧量为2.0%~2.2%,热值均高于42 MJ·kg~(-1)。This paper describes the process of sorbitol and mannitol conversion to liquid heavier hydrocarbons via reduction with hydroiodic acid under mild reaction conditions. The compositions of the obtained products were analyzed using gas chromatography mass spectrometer( GC-MS) and Fourier transform infrared spectrometer( FT-IR). It is found that the products obtained from C6 polyols were mainly C_(12)H_(16),C_(12)H_(18),C_(12)H_(20),C_(12)H_(22) and C_(18)H_(26). The yields of heavier hydrocarbons from sorbitol,mannitol,and the mixture of sorbitol and mannitol were 81. 1%,73. 2%,and 77. 3%,respectively.To obtain pure hydrocarbon fuels,the obtained crude oil was treated with potassium hydroxide in an alcohol solution followed by rotary evaporation and vacuum distillation. The final liquid hydrocarbons obtained have a water content of 0. 1%,densities of 0. 83 ~ 0. 84 g·mL~(-1),oxygen content of 2. 0% ~2. 2%,and heating values > 42 MJ·kg~(-1) at room temperature,which is potentially a good transportation fuel for diesel replacement.国家自然科学基金项目(21276214

    LTE230-Based Power Wireless Private Network Applications and Implementation on Changdao

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    针对山东长岛特有的复杂海岛环境、交通不便、通信网络分散等问题,提出了建设LTE230系统的发展方案。通过对LTE230系统的优势特点进行分析,着重介绍了多个智能化的应用,该系统在智能电网中发挥了不可替代的作用,其良好的覆盖效果和通信能力可满足当地的应用需求。In Shandong province, targeting Changdao's unique complex island environment, traffi c inconvenience, and the dispersion issues of communication network, the paper proposed the construction LTE230 system development program. Through the analysis of the advantages of LTE230 system characteristics, the paper emphatically introduced multiple intelligent applications. The system played an irreplaceable role in smart grid, its good coverage and communication ability met the local application demand.烟台科技项目(5206051400K9

    Dynamic Evolution of Regional Ecological Services Based on TM Remote Sensing

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    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
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