Lineshape and Rotating-frame Longitudinal Relaxation of Intermolecular Multiple-Quantum Coherences, and its MRI Applications

分子间多量子相干(IntermolecularMultipleQuantumCoherence，iMQC)是核磁共振领域的前沿热点话题之一，对其的理论解释曾引起广泛争议。本文的工作是对iMQC理论的扩展和补充，主要成果如下：一、首次建立了iMQC信号的线形理论。该理论很好地阐述了iMQC谱在线形、峰强、线宽、相位等方面的特点。由于iMQC和辐射阻尼均存在于高极化核自旋体系中，因此它们在信号特征上有很多相似之处。本文从线形角度对二者进行了详细比较，说明了它们是由不同的物理机理引起的。二、首次将自旋锁定技术引入到CRAZED实验的演化期，提出了“旋转坐标系分子间双量子纵向弛豫”的概念。利用偶极场理...Intermolecular multiple-quantum coherence (iMQC) phenomenon is a hot topic in the NMR field and has ever arose great controversy in the theoretical formalism of iMQCs. The results in this thesis can be regarded as an extension and supplement of iMQC theory and its applications, which are summarized as follows: 1. A full theoretical formalism about the lineshape of iMQC spectra was propos...学位：理学博士院系专业：物理与机电工程学院物理学系_凝聚态物理学号：B20022400

Dynamic Phase Correction by Wavelet Analysis in Magnetic Resonance Spectroscopy

【中文文摘】核磁共振实验中某些非平稳效应 (如附加磁场的干扰 )会引起的谱峰相位畸变 ,这类相位畸变不能由常规的一阶或二阶线性相位校正来补偿。本文引入了一种“动态相位校正”方法 ,该方法利用连续小波变换直接从已知参考峰的连续时间—尺度表示中提取瞬时相位等有用信息 ,然后对全谱进行动态相位校正。理论表述和仿真分析表明 :该方法为获得高分辨 NMR谱提供一种新的有效的相位校正方式 【英文文摘】In NMR experiments,the peaks always have some phase distortions perturbed by some non stationary effects,such as additional magnetic fields.These phase distortions can not be removed by the routine first order or second order linear phase correction.In this paper,we introduce a new method called by dynamic phase correction.The distorted information is directly extracted from the known referenced peak at the time scale plane of continue wavelet transform;then apply"dynamic phase correction" to the full spectrum. Theoretic representations and simulation results show that the method provides a new efficient way to reconstruct such phase-distorted国家自然科学基金重点项目 ( 10 2 3 40 70 );; 福建省自然科学基金 ( A0 2 10 0 0 3 )资助项

菊芋块茎制高果糖浆的研究

通过菊芋干片与菊粉提取液的制备、菊粉酶解、精制生产高果糖浆，菊粉酶解的适宜条件为：底物糖浓度12%，加酶量26u/g糖，PH5.0-5.5，最适温度为50℃，酶解6H，底物降解率可达98.5%。菊粉酶解液经活性炭脱色、离子交换树脂处理、减压浓缩等步骤，制得糖浆的固形物含量为73.8%，果糖含量（占固形物）为83.6%，同时对糖浆的dE值、色度、灰分、微生物含量等指标进行了测定

厌氧条件在不同Fe( II) 浓度测定方法中必要性的比较研究

厌氧是目前Fe(II)测定方法中常选择的处理方式,但是不可避免会给实验操作带来不便。为了方便、准确地测定铁还原体系中的Fe(II)浓度,对比研究了厌氧条件对草酸—草酸铵和盐酸两种典型浸提方法测定Fe(II)浓度的影响。结果表明:对于草酸—草酸铵浸提法,厌氧条件是必须的,以防止提取液中的Fe(II)被氧化,而且样品浸提1 h 便可用于Fe(II)的测定;然而对于盐酸浸提法,厌氧条件却并不是必须的,对Fe(II)浓度测定基本不产生影响。因此,为简化实验操作或在没有厌氧条件的情况,可利用盐酸浸提法测定铁还原体系中Fe(II)浓度

动脉粥样硬化性肾动脉狭窄的早期发现

探讨冠状动脉造影同时行肾动脉造影的必要性及动脉粥样硬化性肾动脉狭窄的相关危险因素分析。共 4 91例临床疑似冠心病患者行冠状动脉造影同时行非选择性或选择性肾动脉造影 ,并对相关的临床因素进行评价 ,筛选出动脉粥样硬化性肾动脉狭窄的独立危险因素。冠心病组患者中动脉粥样硬化性肾动脉狭窄的发病率为2 0 % ,显著高于非冠心病组 (2 .6 % )。冠心病、外周血管疾病是动脉粥样硬化性肾动脉狭窄的独立危险因素 (多元Logistic回归分析示 ,P <0 .0 0 1、P =0 .0 0 3) ,是其早期发现的指标。对怀疑有冠心病的患者 ,在冠状动脉造影同时行肾动脉造影有助于动脉粥样硬化性肾动脉狭窄的早期发现

Computer Simulation on the Radiation Damping and Relaxation Processes in NM

【中文文摘】对核磁共振弛豫过程和辐射阻尼效应进行了理论分析和计算机模拟,以直观明了的方式描述了这些物理过程,并对模拟结果进行了讨论.模拟结果表明:横向弛豫和纵向弛豫过程在辐射阻尼很小时,不管实验参数如何设定,磁化矢量路径始终发生在以平衡态磁化矢量为半径的球内;当受到强辐射阻尼影响时,磁化矢量路径则发生在以平衡态磁化矢量为半径的球面上. 【英文文摘】Theoretical analysis and computer simulations of radiation damping and relaxation processes in NMR were performed. Simulation results showed that (1) when the effect of radiation damping was ignored, the pathway of magnetization vector was always in a sphere, of which the radius was equal to the magnitude of the magnetization vector at equilibrium state; (2) when the effect of radiation damping was much stronger than the relaxation effect, the pathway of magnetization vector was on the sphere. The results presented herein are helpful to understand the physical properties of these processes.国家自然科学基金(10234070,10005006);福建省自然科学基金(A0210003)资

Study on N X and N Γ Luminescence in GaAs 1- x P x ∶N( x =0.4) Alloys

本文采用变温条件下的光致发光谱和选择激发发光谱对混晶gAAS1-XPX∶n（X＝0.4）中的nX和nΓ发光带进行了研究.在选择激发条件下，实验未观察到混晶gAAS1-XPX∶n（X＝0.4）中nΓ→nX的带间能量转移现象.从变温光致发光谱得到在温度T＜50k时，nΓ和nX的激活能分别为EA（nΓ）＝5.8MEV和EA（nX）＝11.2MEV；在温度T＞50k时，nΓ和nX的激活能分别为EA（nΓ）＝67MEV和EA（nX）＝32MEV.根据实验结果，我们提出，nX和nΓ中心分别来自孤立n中心和n束缚激子分子的发光.Abstract We have performed a PL research on the N X and N Γ band in GaAs 1- x P x ∶N( x =0.4) samples at low temperature.The experimental results show that there does not exist any N Γ→N X interband energy transfer process in GaAs 1- x P x ∶N( x =0.4) samples.In the temperature region T 50K, the activation energy of N X and N Γ bands are 32meV and 67meV, respectively.According to experimental results and analysis, a model in which N X band comes from isolated N X centers and N Γ band comes from N X bound exciton molecule is suggested.国家自然科学基金;福建省自然科学基

The Phonon Sidebands of Excitons Bound to NN 1 Trap in GaAs 1-x P x ∶N( x = 0.88) Alloys

采用选择激发的实验手段，在混晶gAAS1-XPX∶n（X＝0.88）的光致发光谱中观察到nn1对束缚激子发光的声子伴线.通过荧光谱线窄化效应，在发光谱中得到与gAP∶n低温光致发光谱中A线相似的nn1线的声子伴线精细结构，其中包括TA，lA，lO等声子伴线.这个结果在实验上有力地证实了在混晶gAAS1-XPX∶n中的确存在着nn1发光中心.By using selective excitation technique, the phonon sideband of NN 1 pair emission is observed in GaAs 1-x P x ∶N( x = 0.88) alloys. Due to Fluorescence line narrowing, the Fine structure of phonon sidebands of NN 1 pair emission , which is very similar to that of A line in GaP∶N, including TA, LA, LO phonons, is distinguished.This result conFirms that the NN 1 centers do exist in GaAs 1-x P x ∶N alloys experimentally.国家和福建省自然科学基

Application of wavelet analysis for data post-processing of NMR water peak suppression

【中文文摘】介绍了将小波多分辨分析 (MRA)用于核磁共振 (NMR)自由感应衰减 (FID)信号的水峰抑制。结果表明 :这是一种能有效抑制NMR强水峰的数据后处理方法。该方法操作简便 ,引入畸变信息少 ,抑制效果好 ,对邻近水峰的共振峰影响小 ,可得到相位纯正、基线平坦的谱。 【英文文摘】Wavelet multi-resolution analysis has been used for suppressing water peak in free induced signals of NMR. The experimental results demonstrate that this is an effective data post-processing technique to remove strong water signals. The method is simple to operate and the spectra with pure phase and flat baseline can be obtained.国家自然科学基金 (10 2 3 40 70和 10 0 0 5 0 0 6);; 福建省自然科学基金 (C0 110 0 2 4)资助项

The Transient Spectroscopic Study on Tenary GaAs 1-x P x ∶N Alloys

采用皮秒量级的超快速光谱技术，分析了混晶gAAS1-XPX∶n材料发光瞬态过程.结果证实了材料随组份变化，从间接带到直接带（XC＝0.45k，77k）转变的带增强效应.对nX发光带不同能量位置的发光衰退测量还表明nX带同时存在着快速的带内隧穿转移和较慢的发光衰退过程The pico second ultraFast spectroscopic technology is used to study the tenary GaAs 1-x P x∶ N alloys.The results conFirm the band structure enhancement eFFect in GaAs 1-x P x∶ N alloys.The PL decay measurements of N X band show that the Fast intraband tunneling and slow luminescent decay coexist in GaAs 1-x P x∶ N alloys.国家和福建省自然科学基金;中山大学超快速激光光谱学国家重点实验室资