Low-temperature Sintering of Ba5Nb4O15-based Microwave Dielectric Ceramics and Gel-casting of MCT ceramics

本论文采用传统的固相法低温制备Ba5Nb4O15陶瓷，研究了烧结助剂、B位离子取代和工艺因素对陶瓷结构与介电性能的影响，并对陶瓷介电机理进行初步的探讨，还应用凝胶注模成型工艺制作了MCT陶瓷微波器件。 分别采用B2O3、LiF和B2O3-Bi2O3添加对Ba5Nb4O15陶瓷进行低温烧结，并对低温烧结行为、显微结构以及微波介电性能进行研究。实验发现少量B2O3、LiF添加可有效降低Ba5Nb4O15陶瓷的烧结温度至920℃左右；而B2O3-Bi2O3联合添加则随Bi2O3加入量的增加烧结温度先略有降低后升高；三种助剂均可在一定程度上改善Ba5Nb4O15陶瓷的谐振频率温度系数(τf)，同时也...In this thesis, Ba5Nb4O15 ceramics were prepared via conventional mixing oxide route, and the effects of sintering aid, ionic substitutions and processing factors on chemical structure and dielectric properties of the samples were systematically investigated. Dielectric mechanisms of the ceramic were also discussed in this thesis. In addition, gel-casting forming process was used to fabricate micr...学位：工学硕士院系专业：化学化工学院材料科学与工程系_材料学学号：20043602

Synthesis of dibenzoylmethane analogues and study of their activities

二苯甲酰甲烷（1，3-Diphenyl-propane-1，3-dione，DBM）是从甘草中提取的一种具有β-二酮结构的黄酮类天然产物，在溶剂萃取、有机合成、化学分析、立体化学、热塑性塑料用光、热稳定剂等领域有着广泛的应用。近年来，人们发现DBM具有抗氧化，抗炎，抗HIV和抗肿瘤等药理作用，并具有毒性低、生物利用度高和资源丰富等优点，能够诱导细胞周期停滞和细胞凋亡，是一种很有发展前景的抗肿瘤药。本论文以DBM为母核，合成了一系列具有β-二酮结构的类似物，采用红外、质谱和核磁等谱学方法进行表征，并用人体肝癌BEL-7402、纤维肉瘤HT1080细胞和宫颈癌Hela细胞进行体外活性筛选，研究化合...The natural product dibenzoylmethane (1, 3-Diphenyl-propane-1, 3-dione, DBM), obtained from the licorice, is widely used in a variety of fields, such as solvent extraction, organic synthesis, chemical analysis, stereochemistry, thermoplastic plastic and heat-stable inhibitor. Recently, DBM has been found to exhibit numerous biological activities including anti-oxidation, anti-inflammatory, anti-HI...学位：理学硕士院系专业：医学院药学系_药物化学学号：2452008115349

Diffusion mechanisms in the Fe3ASi

In this paper, the possible reasons for the high thermal vacancy concentration and the low migration barriers for the Fe atom diffusion in the DO3 structure Fe3Si have been discussed

四维世界里的钟摆运动:文化视角下的公共管理发展逻辑——兼评《国家的艺术:文化、修辞与公共管理》

公共管理现代化存在全球性的趋同范式吗?对这一问题的回答无疑对明晰我国未来公共管理改革方向具有重要意义。胡德的观点十分明确:以文化与历史结合的视角来看,公共管理趋向同一\"现代\"范式的观点有待商榷,一个更多元的未来更为可信。通过引入网格—团体理论,作者将公共管理组织形式划分为四种类型:等级主义、平等主义、个人主义和宿命论。同时,借由对长时期历史的考察,作者发现,这四种组织形式交替出现;公共管理发展绝非遵循线性替代逻辑,而是钟摆运动逻辑,呈循环上升态势。该研究对现代化的理性思考、对国家艺术的深入探讨,使其成为公共管理研究的里程碑之作。尽管如此,该研究也存在有待商榷之处。此外,本文还探讨了该书对我国的启示意义。福建省社会科学规划项目(FJ2017B025);;\n厦门大学繁荣哲学社会科学项目;;\n中央高校基本科研业务费(20720181099)资

Low temperature sintering of Ba_5(Nb_(1-x)Sb_x)_4O_(15) microwave dielectric ceramics

添加质量分数为1%的H3BO3为助烧剂。研究了Ba5(Nb1–xSbx)4O15(0≤x≤0.2)陶瓷的烧结特性、显微结构和微波介电性能。结果表明:当x≤0.15时,该类陶瓷可在900℃附近烧结,并伴有少量BaSb2O6和BaB2O4相;随着x从0增加到0.2,εr和τf均有较大幅度下降;Q.f先升后降。在900℃烧成温度下,x为0.15的陶瓷获得较好的微波介电性能:εr为29.21,Q.f为13 266 GHz,τf为11×10–6℃–1,并能与Ag电极很好相容,基本满足LTCC工艺的要求。The sinterability,microstructure and microwave dielectric properties of Ba5(Nb1–xSbx)4O15(0≤x≤0.2) ceramics doped with H3BO3 were investigated.It is found that all of the Ba5(Nb1–xSbx)4O15(x≤0.15) ceramics with the addition of 1 % H3BO3 could be sintered at about 900 ℃.The interactions between Ba5(Nb1–xSbx)4O15 and H3BO3 lead to the formation of BaSb2O6 and BaB2O4 phases.With x increasing from 0 to 0.2,εr and τf decrease greatly.Quality factor increase and then decrease.At a sintering temperature of 900 ℃,the ceramic of Ba5(Nb0.85Sb0.15)4O15 with addition of 1 % H3BO3 exhibite the optimal microwave dielectric properties of εr =29.21,Q.f =13 266 GHz,τf =11×10–6 ℃–1 and good compatibility with silver electrodes,which is a suitable low-temperature cofired ceramic(LTCC)

中国式政府监管:特征、困局与走向

在市场经济体制中,政府监管是政府职能的核心。审批和执法是中国式监管的主要手段。本文从一种宏观的视角归结中国式监管的特点,剖析其内在的失效原因,指出重审批轻监管是中国式监管的弊病,并由此引发诸多流弊。因此,应重塑政府监管的中国模式,将风险监管运用于日常监管机制中。从运动式监管走向风险监管、建设风险监管型政府是推进国家治理体系和治理能力现代化的现实需求。福建省社会科学规划项目(FJ2017B025);;厦门大学繁荣哲学社会科学项目;;教育部哲学社会科学研究重大课题攻关项目“基本公共服务均等化实施效度和实现程度研究”(18JZD047

Low temperature sintering of Ba_5(Nb_(1-x)Sb_x)_4O_(15) microwave dielectric ceramics

[中文文摘]添加质量分数为1%的H3BO3为助烧剂。研究了Ba5(Nb1–xSbx)4O15(0≤x≤0.2)陶瓷的烧结特性、显微结构和微波介电性能。结果表明:当x≤0.15时,该类陶瓷可在900℃附近烧结,并伴有少量BaSb2O6和BaB2O4相;随着x从0增加到0.2,εr和τf均有较大幅度下降;Q.f先升后降。在900℃烧成温度下,x为0.15的陶瓷获得较好的微波介电性能:εr为29.21,Q.f为13 266 GHz,τf为11×10–6℃–1,并能与Ag电极很好相容,基本满足LTCC工艺的要求。[英文文摘]The sinterability, microstructure and microwave dielectric properties of Ba5(Nb1–xSbx)4O15(0≤x≤0.2) ceramics doped with H3BO3 were investigated. It is found that all of the Ba5(Nb1–xSbx)4O15(x≤0.15) ceramics with the addition of 1 % H3BO3 could be sintered at about 900 ℃.The interactions between Ba5(Nb1–xSbx)4O15 and H3BO3 lead to the formation of BaSb2O6 and BaB2O4 phases.With x increasing from 0 to 0.2,εr and τf decrease greatly. Quality factor increase and then decrease.At a sintering temperature of 900 ℃，the ceramic of Ba5(Nb0.85Sb0.15)4O15 with addition of 1% H3BO3 exhibite the optimal microwave dielectric properties of εr =29.21, Q·f =13 266 GHz, τf =11×10–6 ℃–1 and good compatibility with silver electrodes, which is a suitable lowtemperature cofired ceramic (LTCC)

3-芳基-α,β-不饱和酮介导的细胞凋亡机理研究(英文)

选择了与3-芳基-α,β-不饱和酮结构关联的六个天然产物,研究了3-芳基-α,β-不饱和酮在诱导人肺癌细胞A549凋亡的作用与分子机制。结果表明,六个天然产物的细胞毒活性来源于3-芳基-α,β-不饱和酮结构,缺失该结构,活性明显降低;NAC明显抑制3-芳基-α,β-不饱和酮诱导的细胞毒活性,3-芳基-α,β-不饱和酮诱导的A549细胞凋亡涉及迈克尔加成、内质网应急和线粒体依赖的细胞凋亡分子机理

急性甲醇中毒大鼠模型及其眼部改变的研究

【目的】探讨急性甲醇中毒大鼠模型的制作方法及其眼部改变，为研究中毒后视功能损害及救治方法建立基础。【方法】SD大鼠32只，随机分为A（低剂量甲醇组）、B（高剂量甲醇组）、C（生理盐水对照组）、D（空气对照组）4组，每组8只。A、B组吸入N2O／O2混合气及不同剂量甲醇灌胃，C组吸入N2O／O2混合气及生理盐水灌胃，D组置于正常空气中并按B组剂量给予甲醇灌胃，观察各组大鼠一般情况、体质量及眼部改变、静脉血甲醇浓度、视网膜电图和视网膜组织学改变。【结果】染毒大鼠反应迟钝、运动失调，视盘充血水肿、视网膜点状出血，A组大鼠体质量为（187±12）g，B组为（176±131g，较C、D对照组显著减轻（P〈0．05）；A组视网膜电图a、b波振幅分别为（87±13）μV、（187±38）μV，B组a、b波振幅分别为（53±19）μV、（132±39）μV，与对照组相比明显下降（P〈0．05）；视网膜在光镜下表现为各层细胞水肿、排列紊乱及空泡化；电镜下细胞凋亡，线粒体肿胀、嵴断裂；B组动物上述改变尤其明显。【结论】吸入N2O/O2混合气及甲醇灌胃可建立急性甲醇中毒的大鼠模型，出现典型的视网膜结构和功能改变

Study of Marine Biocorrosion Using AFM and Molecular Techniques

　生物膜在自然界无处不在,但生物膜造成的腐蚀却基本上被忽视.本文展示了几种化学和微生物学新方法在海水微生物腐蚀研究中的应用.原子力显微镜用来揭示生物最初形成的机理和钢在受污染海水中的腐蚀程度,16SrDNA/RNA技术则用来分析生物膜中的微生物组成.试验结果表明,微生物腐蚀在6d内就已经开始了,腐蚀体积与时间的2.83次方成正比;腐蚀生物膜中的微生物以硫酸还原菌(脱硫弧菌科)为最多,其次是梭状芽孢杆菌.Biofilm is ubiquitous in nature.However,corrosin caused by biofilm is still by and large overlooked.This presentation is to demonstrate the applications of several newly developed analytical techniques in chemisrty and microbiology for the study of marine biocorrosion on steel.AFM(atomic force microscopy) was applied to investigate the initial formation mechanism of biofilm and the degree of corrosion of steel in polluted seawater.DNA/RNA_related molecular techniques were used to analyze the microbial composition corrosive biofilm. Results showed that microbial corrosion began within six days, and the corroded volume in the increased as a power function of time with an index 2.83. Most of the microbes identified in the corrosive biofilm were sulfate_reducing Desulfovibrionaceae(46.5%),followed by Clostridiaceae(29.4%).作者联系地址：香港大学土木工程系环境工程研究中心,香港大学土木工程系环境工程研究中心,香港大学土木工程系环境工程研究中心 香港 ,香港 ,香港Author's Address: Centre for Environmental Engineering Research Department of Cicil Engineering,The University of Hong Kong,Hong Kong,Chin