Sparse Reconstruction Algorithm of NMR Spectroscope Based on Approximate l0 Norm Minimization

在核磁共振(NMR)波谱中，过长的数据采集时间会使化学以及分子生物学领域的高分辨率多维谱应用难以实现。传统的解决办法是使用随机非均匀采样代替奈奎斯特采样，但这样会使谱图质量受损。压缩传感的出现为此提供了更好的解决办法，合适的压缩传感重建算法可以通过很少的随机非均匀采样将谱图高质量的重建出来。目前压缩传感重建算法在NMR波谱领域已经得到了比较充分的应用，其中使用较多的重建算法是基于l1范数最小化的基追踪算法，为进一步改进重建效果，本文提出了两种基于近似l0范数最小化的压缩传感重建算法，主要成果如下： 一、介绍了一种基于近似l0范数最小化并可用于谱图重建的压缩传感重建算法，名为“平滑l0范数最...The problem of long sampling time often limits many applications of the multidimensional NMR spectroscopy in chemistry and molecular biology. A common approach is to replace the Nyquist sampling with random non-uniform sampling (NUS). However, NUS is associated with inherent loss of spectrum quality. Now Compressed Sensing (CS) theory provides a good solution. A suitable CS reconstruction algorith...学位：理学硕士院系专业：物理与机电工程学院_无线电物理学号：1982010115285

Rational synthesis of an atomically precise carboncone under mild conditions

在已知的碳的存在形态中，还有一种锥型的碳结构，早在50年前人们在热解碳时发现了这类结构，此前也常被人们称为碳纳米锥，虽然这类碳纳米锥有望作为扫描隧道显微镜的探针、场发射头等替代材料，但始终未能找到合适方法精准地合成它们。因此，这类锥型碳材料尚未得到人们足够重视和开发。功能团簇材料创新研究群体的谢素原、张前炎课题组与美国波士顿学院的Lawrence Scott教授合作，首次通过有机合成途径，在温和的条件下合成得到了首例结构明确的碳锥单元（碳锥子）C70H20及其可溶衍生物。他们通过实验、理论计算、结构分析，最终在他们合成的碳锥子结构中，仅有1个五元环在锥顶，而在锥顶和锥缘之间（围绕着中心五元环）有2圈由六元环组成的完整的稠圈层，谢素原等将这一碳锥子命名为carboncone[1,2]。通过这一典型的碳锥子（carboncone[1,2]），有望借助气相沉积等技术不断增加稠圈层数（m）来制备具有确定锥角的系列单壁纳米碳锥（carboncone[1,m>2]）。随着研究的深入，不久的将来人类有望合成出其它四种不同锥角的碳锥子（carboncone[n=2-5,m]），完整地研究探索和开发利用这类锥型结构的碳材料。 化学化工学院2015级硕士生朱正钟（主要负责合成）和2017级博士生陈佐长（主要负责理论计算）为该论文的共同第一作者。Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.This research was supported by the National Natural Science Foundation of China (21771152, 21721001, 21390390, 21827801, 51572231, 21571151, and 21701134), the 973 Program of China (2015CB932301), the Major Science and Technology Project between University-Industry Cooperation in Fujian Province (2016H6023), and the Fundamental Research Funds for the Central Universities (20720170028 and 20720160084). This research was also supported financially by the U.S. National Science Foundation (CHE-0809494 and CHE-1149096). 研究工作得到国家自然科学基金（21771152等）、科技部重大科学研究计划项目（2015CB932301）和福建省高校产学合作项目、中央高校基本科研业务费、美国国家科学基金等的资助

A Sparse Reconstruction Algorithm for NMR Spectroscopy Based on Approximate l_0 Norm Minimization

在核磁共振(nMr)波谱中,过长的数据采集时间会使很多化学以及分子生物学领域的高分辨率多维谱应用难以实现.传统的解决办法是使用随机非均匀采样代替奈奎斯特采样,但这样会使谱图质量受损.压缩传感的出现为此提供了更好的解决办法,合适的压缩传感重建算法可以通过很少的随机非均匀采样将谱图高质量的重建出来.该文先介绍了一种可用于谱图重建的压缩传感重建算法,名为“平滑l0范数最小化法“,然后针对该算法对采样噪声鲁棒性较差的缺点进行了改进.通过将改进后的算法与原算法在一维实数域信号以及nMr波谱信号重建实验中进行对比后表明,改进后的算法对噪声的鲁棒性明显提高,并能获得更好的重建性能.Long acquisition time often hinders the routine application of multidimensional NMR spectroscopy.A common approach to reduce the acquisition time is to replace the commonly used Nyquist grid sampling scheme with a random non-uniform sampling(NUS)scheme.However,NUS is inherently associated with degradation of spectrum quality.It has been demonstrated recently compressed sensing(CS)algorithms can be used to reconstruct high-quality spectra from sparse NUS data.In this paper,a CS reconstruction algorithm called"Smoothed l0Norm Minimization"was introduced.The typical version of the algorithm was then modified to improve its robustness under high noise condition.The improved algorithm was applied to reconstruct 1Dreal-valued signal and 2D NMR spectroscopy,and the results were compared with those obtained by other methods.The results showed that the algorithm proposed had better robustness to noise,and could be used to reconstruct high-quality spectra with fewer sampling data.国家自然科学基金资助项目(11105114、11174239和61201045); 中央高校基本科研业务费资助项目(2010121010

发泡镍对肺冲击伤的防护效果及其机理研究

本研究采用激波管,探讨了发泡镍对肺冲击伤的防护效果和防护机理。结果表明,发泡镍可明显减轻肺冲击伤的程度,降低死亡率。发泡镍的防护作用可能与其降低冲击波超压峰值、延长正压上升时间和缩短正压作用时间有关。结果提示发泡镍是一种较为理想的冲击伤防护材料