In-Situ Spectroscopic Analysis of Domain Switching in Ferroelectric Ceramics

铁电陶瓷材料的电畴在外场作用下反复翻转即畴变引起的材料结构变化，是导致铁电材料性能衰变和破坏的原因。掌握和了解外场作用下的铁电畴变行为对研究其失效机理、提高可靠性具有重要的理论指导意义。本论文试图通过研究外加电场作用下的PLZT铁电陶瓷材料原位Raman和XRD谱学变化规律，探讨建立表征铁电陶瓷材料畴变行为及其与材料宏观极化强度关系的定量分析理论和方法，为进一步理解铁电体的非线性以及电极化和电疲劳行为奠定基础。 基于晶格动力学理论，考虑与极性晶格振动有关的长程静电作用的Raman散射机制，本论文建立了铁电陶瓷材料中的特征光学模散射峰强度比与激光偏振方向和电畴取向之间的关系，定义了反映铁电陶瓷...Domain switching under an electric field has been recognized as a fundamental origin causing deterioration and failure of the properties for ferroelectric ceramics. It is, therefore, theoretically and practically important to study the failure mechanism and to improve the reliability of materials by understanding the domain switching behaviors under different loading conditions. In this work, th...学位：工学博士院系专业：材料学院材料科学与工程系_材料物理与化学学号：2072007015346

Phase transition of lanthanum-doped lead zirconate titanate ceramics during electric-field-induced domain switching

利用原位Xrd技术研究未极化掺镧锆钛酸铅(PlzT)铁电陶瓷在不同直流电场加载过程中(002)和(200)衍射峰峰强与电场强度的关系,基于铁电畴取向分布的考虑,对(002)和(200)衍射峰峰强进行定量分析。通过对原位Xrd谱进行四方相和单斜相的分峰拟合处理,初步探讨电场强度对铁电陶瓷电致畴变和电致相变的影响。结果表明:对于PlzT试样,在电场加载过程中除了发生电致90°畴变外,还可能发生从四方相到单斜相的电致相变。在不同电场强度作用下,电致畴变与电致相变是一个相互竞争的过程,电致畴变是主要的,而电致相变相对减少。Variations of the peak intensities of(002)and(200)diffraction peaks(I(002),I(200))with the applied electric fields were studied by in-situ X-ray diffraction method during the applications of different electric fields on the unpoled lanthanum-doped lead zirconate titanate(PLZT)ceramics.Considering the distribution of domain orientation,the quantitative analyses of peak intensities of I(002)and I(200)were performed.Based on the multi-peak curve fitting to the in-situ XRD spectra,the effects of the applied electric fields on the electric-field-induced domain switching and phase transition were preliminarily discussed.The results show that the electric-field-induced 90° domain switching occurs in PLZT specimens under the applied electric fields,at the same time,the electric-field-induced phase transition from tetragonal to monoclinic could also happen.The electric-field-induced domain switching and phase transition occur competitively in different electric fields.The major process is domain switching,while the minor process is phase transition.国家自然科学基金资助项目(11372263); 福建省特种先进材料重点实验室开放课题资助项

Effect of Electric Fatigue on Electric-Induced Domain Switching for Lanthanum-doped Lead Zirconate Titanate Ceramics

在不同电疲劳周次下,对未极化掺镧锆钛酸铅铁电陶瓷在不同直流电场加载下得到的原位X射线衍射(Xrd)谱和撤掉不同直流电场后得到的非原位Xrd谱的(002)与(200)晶面衍射峰强与电场强度(EA)的关系进行研究。通过计算90°畴变体积分数发现,在电疲劳过程中,电场撤掉前后的90°畴变体积分数均随EA呈蝶形曲线变化。在低电场作用下,铁电畴更趋向于沿平行试样表面方向,而在EA=2 000 V/MM作用下,当电疲劳至106时,材料中有约5%的铁电畴被钉扎,有约6%的铁电畴在电场撤掉瞬间转回平行试样表面方向。电场撤掉后的90°畴变体积分数能直接反映铁电材料剩余极化程度。The variations of intensity values for(002) and(200) diffraction peaks from X-ray diffraction measurements with and without applied electric fields(EA) for unpoled lanthanum-doped lead zirconate titanate(PLZT) ceramics were investigated during the different cycle numbers of electric fatigue.The results show that the relations between 90° domain switching content(in volume) and the magnitude of EA in the presence and absence of EA during the electric fatigue are typical butterfly-curve modes.Also, the domains parallel to the sample surface are more stable at lower EA.When EA=2 000 V/mm and the cycle number of electric fatigue is 106, the pining of 5% domain walls occurs.However, 6% domains instantly return to the direction parallel to the sample surface without EA.The 90° domain switching content without EA can be used to show the degree of remanent polarization.国家自然科学基金(11372263)资助项

Content of gentiopicroside and loganic acid in Radix gentianae and their fingerprints

To develop a HPLC-DAD-ESI-TOF/MS analysis method for the determination of gentiopicroside and loganic acid in Radix gentianae samples and for the research of their fingerprints.The samples were extracted using ASE for 10 min under 100 ℃ and 9.65 MPa,and divided into water phase and chloroform phase and analyzed them with HPLC-DAD-ESI-TOF/MS method respectively.Based on this method,the HPLC fingerprints of Radix gentianae were established.Comparing the spectrogram and mass spectrum of the chromatogram peak with the reference value,three compounds in water phase were identified as gentiopicroside,asafetida acid and loganic acid.There is no report of the compounds in chloroform phase.The content of gentiopicroside and loganic acid in samples of different groups were determined,separately.The fingerprints were compared by the software of the similarity evaluation system for chromatographic fingerprint.The water phase fingerprint congruence coefficients of samples from six different areas were above 0.90,however,the chloroform phase fingerprint congruence coefficients were within 0.62-0.99.This method can be used for determination of potent component in Radix gentianae and its quality control.Radix gentianae from different producing areas have the largest diversities,and the diversities embodied in the content of chloroform phase compounds.青岛“2004将才计划”(04-3-JJ-11);; 国家海洋局青年基金资助项目(2005602);; 崂山区政府区校共建生物医药研发测试中心资助(LS-05-KJZX-76)

Determination of Gentiopicroside and Loganic Acid in Radix Gentianae by MEKC and MEEKC Mode

目的建立胶束电动毛细管色谱(MEKC)和微乳液毛细管电动色谱(MEEKC)分析龙胆药材中龙胆苦苷和马钱子苷酸含量的方法。方法采用加速溶剂萃取法(ASE)对龙胆药材进行提取,萃取温度:100℃,压力:9.65MPa,萃取时间:10min。采用未涂层熔融石英毛细管(内径75μm,有效长度50cm)。分别考察了两种分离模式下电泳介质的构成和电泳过程中的各操作参数对样品分离过程的影响,优化了MEKC和MEEKC的分析条件,在各自对应的缓冲液体系下,MEKC和MEEKC分离电压分别为30和22kV,柱温均为25℃,检测波长均为238nm。结果在选定的工作条件下,龙胆苦苷和马钱子苷酸与其他组分达到了基线分离,两种成分的浓度与其响应信号值之间具有较好的线性相关性,加标回收率在96.3%～105.1%之间,检测限均低于10mg·L-1,对6处不同产地的龙胆药材进行了分析,并对测定结果进行了t检验,结果表明,两种模式下,测定结果之间不存在显著性差异,而不同产地的龙胆药材的龙胆苦苷和马钱子苷酸含量之间存在较大差异。结论本方法简便,准确,快速,重现性较好,可用于龙胆药材有效成分的含量测定和质量控制。OBJECTIVE To develop MEKC and MEEKC modes for the determination of gentiopicroside and loganic acid in extracts of Radix Gentianae. METHODS The analyte was extracted from Radix Gentianae samples by accelerated solvent extraction, and the extraction conditions were optimized. Separation and determination were carried out on a bared fused silica capillary(50 cm×75 μm) with corresponding buffer. The run voltage of MEKC and MEEKC were 30kV and 22 kV respectively. Detection wavelength of DAD was at 238 nm and column temperature was 25 ℃. RESULTS The developed ASE-HPCE method was simple and reliable for the determination of gentiopicroside and loganic acid in Radix Gentianae samples with a broad linear dynamic range, a recovery range of 96.3%～105.16%,and the detection limit was below 10 mg·L-1. The contents of gentiopicroside and loganic acid in six samples from different regions were determined by the developed method in two modes. T-test value indicated that the determined contents of gentiopicroside and loganic acid by MEKC and MEEKC were consistent. CONCLUSION The method is simple,accurate,rapid and with good reproducibility.It can be used to determine active components in Radix Gentianae.国家自然科学基金重点项目(20235020);; 青岛“2004将才计划”(04-3-JJ-11);; 崂山区校区共建生物医药研发测试中心资助(LS-05-KJZX-76

大孔吸附树脂分离纯化龙胆药材中龙胆苦苷和马钱子苷酸的研究

目的:建立利用大孔吸附树脂对龙胆药材中龙胆苦苷和马钱子苷酸进行富集和分离纯化的方法。方法:采用加速溶剂萃取法对龙胆药材中两种有效成分进行高效提取,比较了D301,AB-8,D101,XDA-1四种大孔树脂对龙胆苦苷和马钱子苷酸的吸附性能,最终确定采用D301型大孔对脂对二者进行富集吸附,对其工艺参数进行优化,全程采用高效液相色谱进行目标化合物浓度检测。结果:化优后的工艺参数为:上样浓度:0.2 g/mL,最大上样量:0.25 g龙胆药材/g树脂,最佳静态吸附时间:8 h,采用8%和55%的乙醇溶液对龙胆苦苷和马钱子苷酸分别进行洗脱;龙胆苦苷和马钱子苷酸分别富集在8%和55%的乙醇洗脱液中,洗脱液浓缩后冷冻干燥,可得到纯度分别为74.3%和80.9%的粗产物,龙胆苦苷和马钱子苷酸的回收率分别为70.11%和67.82%。结论:此法效率较高,操作简便,即可用于实验室制备少量的难以购置的标准品,也可进行放大研究,用于工业生产。国家自然科学基金重点项目(20235020);; 青岛“2004将才计划”(04-3-JJ-11);; 共建生物医药研发测试中心(LS-05-KJZX-76)资

苯硫酚对固氮酶催化活性的影响

研究了苯硫酚对棕色固氮菌固氮酶催化底物还原活性的影响。结果表明:当反应体系中固氮酶钼铁蛋白与苯硫酚的摩尔比为1:4时,固氮酶的乙炔还原活性比对照组下降了62.3％,下降的幅度随着苯硫酚浓度的升高而增大;但在乙炔存在的情况下,固氮酶的放H_2活性随着苯硫酚的浓度的升高而升高。在氩气氛下,苯硫酚浓度的升高对固氮酶放H_2活性的影响不明显。这一现象有可能是由于苯硫酚取代与铁钼辅基的Fe_1原子连接的半胱氨酸的巯基而引起的

钼酸盐柠檬酸盐络合物及有机酸对棕色固氮菌生长的影响

将经过0.9%NaCl溶液处理8h的棕色固氮菌(AzotobactervinelandiiOP)作为菌种分别接入Burk′s培养基和用不同有机酸替代柠檬酸三钠或用不同等摩尔的钼络合物替代钼酸钠的各种改良的Burk′s培养基中,分别测定菌体生长曲线和固氮活性.结果发现,与Burk′s培养基相比,以高柠檬酸、苹果酸、马来酸替代柠檬酸三钠或以K6[Mo2O5(cit)2]·5H2O、K4[Mo2O5(Hcit)2]·4H2O和Na2[MoO2(Hcit)]·3H2O替代柠檬酸三钠和钼酸钠的培养基能促进菌体的生长;以乙醇酸替代柠檬酸三钠的培养基则会抑制固氮菌的生长;各种培养条件下菌体细胞的C2H2还原活性表现了类似的规律.讨论了固氮酶活性中心FeMoco在装配过程中钼的可能运输方式和装配机理

Vaccination mediates protection against Penicillium marneffei in BALB/c mice

P. marneffei is the unique thermal dimorphic fungus among Penicillium spp. which grows as mycelium at 25 ºC and as yeast at 37 ºC. Intravascular injection of lethal dose of P. marneffei spores might lead to systemic infections in BALB/c mice, and the hepatic tissue seemed to suffer from the most severe infection with significant high CFU value than other organs. In this study, we aimed at generating a candidate vaccine for P. marneffei using two independent approaches, recombinant Mp1p protein and live-attenuated strain vaccination. Antigenic mannoprotein Mp1p of P. marneffei strain PM1 was cloned and expressed in E. coli and Pichia pastoris, and these two types of recombinant Mp1p was used to perform vaccination study. Both subcutaneous administration of recombinant Mp1p with Freund’s Adjuvant and intraperitoneal injection of Mp1p with Sigma Adjuvant System elicited efficacious resistance against lethal dose challenge of PM1 in BALB/c mice. Four different strains PM1, PM18, PM25 and PM36 were chosen to detect the protective breadth of strain coverage of recombinant Mp1p and results showed that recombinant Mp1p only generated protection against strain PM1 but failed to resist against the infections of other P. marneffei isolates. Fungal burden and histopathological examination elucidated that recombinant Mp1p with SAS had efficacy in suppression and clearance of hepatic and splenic PM1 yeast cells, but failed to control the dissemination of PM25 which caused invasive hepatic and splenic infection and malignant inflammatory response. Thus, we hypothesized that recombinant Mp1p elicited a narrow breadth of strain coverage due to the high degree of polymorphism of MP1 and its homologues. Depletion of virulence gene MP1 from strain PM1 yielded one live-attenuated P. marneffei strain BC122. BC122 vaccinated mice were able to resist infections due to different P. marneffei isolates, including strain PM1, PM18, PM25 and PM36. Thus, it displayed wide strain coverage. Fungal burden analysis elucidated that both PM1 and PM25 yeast cells in mice spleens and livers presented a trend of clearance. H&E and GMS staining of vaccinated mice hepatic tissues founded that both PM1 and PM25 yeast cells were fast sequestered in granulomas and killed progressively, and many empty granulomas were seen since days 6 post-infection. Intracellular staining showed that the frequency of IFN-γ producing CD4+ T cells in hepatic tissue was significant higher than the peripheral blood, which might elucidate the influx of functional hepatic Th1 cells. The absolute number of hepatic Th1 cells in immunized mice were also significant greater than that of PBS control group. In addition, CD4 deficient mice seemed to be vulnerable even to the virulence attenuated strain BC122. Furthermore, the percentage of hepatic Th17 cells rocketed at days 2 post-infection then fast decreased to bottom out which was not consistent with the tendency of fungal clearance. Thus, we concluded that vaccine BC122 had elicited efficacious protection through hepatic Th1 cell immunity in BALB/c mice model. This preliminary study will help us to characterize the mechanisms of exclusive immune response against P. marneffei and provide informative reference for preventive or therapeutic strategies against penicilliosis.published_or_final_versionMicrobiologyDoctoralDoctor of Philosoph

Determination of Alkylphenols in Water by Solid-phase Extraction with on-Column Derivatization Coupled with Gas Chromatography-Mass Spectrometry

以烷基酚(APs)主要降解产物辛基酚(4-t-OP)、壬基酚(4-n-NP)为研究对象,建立了固相萃取(SPE)柱上衍生化、气相色谱-质谱(GC-MS)法测定水中APs的分析方法。以C18柱为固相萃取柱、N,O-(三甲基硅)三氟乙酰胺(BSTFA)为硅烷化试剂,设计五因素四水平正交实验L16(45),对衍生化影响因素、衍生化溶剂、衍生化时间以及SPE主要影响因素pH值、盐度和洗脱剂进行优化;在优化条件下,方法的回收率(高于80%)和重现性(RSD低于10%)结果令人满意,4-t-OP和4-n-NP的仪器检出限分别为3.35ng/L和6.38ng/L。采用建立的方法,回收率略高于传统的SPE萃取衍生法,具有有机溶剂用量少,方法简单快速、灵敏度高的特点,适用于河水和海水中痕量烷基酚的快速测定。An analytical methods based on solid-phase extraction(SPE)with in situ derivatization followed by gas chromatography-mass spectrometry has been developed for the determination of alkylphenols(APs)in water samples.Two important APs,4-n-nonylphenol and 4-t-octylphenol,were selected as the target compounds for method development.The SPE extraction was conducted on a C18 extraction cartridges with on column silylation by bis(trimethylsilyl)trifluoroacetamide.Operationasl parameters including silylation reagent silylation time,pH value,concentration of salts,elulent which are expected to impact on the recoveries of analytes were optimized by orthogonal experimental design.It is shown that the acetone is the best silylation reagent while DCM was efficient in eluting APs from SPE cartridges.The recovery of APs increases slightly with increasing concnetration of NaCl in the range of 0-1.5% of NaCl,beyond the concentration of 1.5%,the recovery of APs starts to decrease.But the recovery of APs reduced by the increase in pH value.The optimised method was further verified by performing spiking experiments in ultrapure water and seawater matrices,with good recovery and reproducibility for all the selected compounds.The method showed better performance than the reported liquid liquid extraction-derivatization method in terms of analytical speed,procedural simplicity and recovery.国家重点创新项目(836)(No.2003AA635180