Crystal morphology is known to be of great importance to the end-use properties of crystal products, and to affect down-stream processing such as filtration and drying. However, it has been previously regarded as too ...Crystal morphology is known to be of great importance to the end-use properties of crystal products, and to affect down-stream processing such as filtration and drying. However, it has been previously regarded as too challenging to achieve automatic closed-loop control. Previous work has focused on controlling the crystal size distribution, where the size of a crystal is often defined as the diameter of a sphere that has the same volume as the crystal. This paper reviews the new advances in morphological population balance models for modelling and simulating the crystal shape distribution （CShD）, measuring and estimating crystal facet growth kinetics, and two- and three-dimensional imaging for on-line characterisation of the crystal morphology and CShD. A framework is presented that integrates the various components to achieve the ultimate objective of model-based closed-loop control of the CShD. The knowledge gaps and challenges that require further research are also identified.展开更多
采用苦味酸和氨水制备出不敏感单质炸药苦味酸铵(C_6H_2(NO_2)_3ONH_4)。在此基础上研究晶形控制剂聚乙烯醇对苦味酸铵形貌及性能的影响,用SEM、XRD、DSC对其进行分析,并测试其撞击感度。结果表明:晶形控制的苦味酸铵性能有很大改观,其...采用苦味酸和氨水制备出不敏感单质炸药苦味酸铵(C_6H_2(NO_2)_3ONH_4)。在此基础上研究晶形控制剂聚乙烯醇对苦味酸铵形貌及性能的影响,用SEM、XRD、DSC对其进行分析,并测试其撞击感度。结果表明:晶形控制的苦味酸铵性能有很大改观,其为粒径0.5μm的类球形,X射线的衍射角和特征峰没有变化,较原样品表观活化能提高4.701 k J·mol-1,热爆炸临界温度提高13.63℃,特征落高(H50)提高7.25%。研究表明通过晶形控制的苦味酸铵更钝感,具有较好的热安定性。展开更多
用苦味酸和氨水制备不敏感单质炸药苦味酸铵。在此基础上研究不同晶形控制剂对结晶因素的分析,通过正交实验设计确定了优化晶形控制工艺条件,得到四种不同晶形的样品。采用显微镜、XRD对其进行表征,并对撞击感度和真空安定性进行测试。...用苦味酸和氨水制备不敏感单质炸药苦味酸铵。在此基础上研究不同晶形控制剂对结晶因素的分析,通过正交实验设计确定了优化晶形控制工艺条件,得到四种不同晶形的样品。采用显微镜、XRD对其进行表征,并对撞击感度和真空安定性进行测试。结果表明:晶形控制剂加入使所得晶体形貌规整、趋于棒状,X射线特征峰强度略有不同,添加3 m L 8%PVP制备晶体的撞击感度和真空安定性最优。展开更多
Hierarchical structures, in which structure is generated and controlled simultaneously at different size scales, have attracted increasing attention due to their potentials in both theoretical research and practical a...Hierarchical structures, in which structure is generated and controlled simultaneously at different size scales, have attracted increasing attention due to their potentials in both theoretical research and practical applications. In this review, a "non-classical crystallization" mechanism is discussed for their possibilities in morphology control of hierarchically-structured materials. Differently, this crystallization route is not based on the attaching and detaching of monomers as happened in the classical case, but through the self-organization of preformed building blocks as nanosized subunits, whose oriented attachment leads to mesocrystals with favorable morphology and texture. Representative materials including both inorganic and organic crystals are reported with possible mechanisms proposed. Synthetic protocols based on this mechanism provide unique inspirations for materials design and could be applied to morphological and structural control of new materials with optimized functions.展开更多
This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal nanocrystals. The seed-mediated growth method has become one of the most efficient ...This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal nanocrystals. The seed-mediated growth method has become one of the most efficient and versatile methods for synthe-sizing high-quality noble metal nanocrystals. The seed-mediated growth method can separate the nucleation and growth stages of metal nanocrystals, and thus provide better control over the size, size distribution, and crystallographic evolution of metal nanocrystals. Because of its high controllability, the seed-mediated growth method is especially promising in providing mechanistic insights into the growth mechanisms of noble metal nanocrystals. In this review, the thermodynamic and kinetic parameters for the nucleation and growth of noble metal nanocrystals are systematically summarized. Mechanistic understanding of these parameters is provided. These studies provide useful guidelines for the rational design and synthesis of novel noble metal nanocrystals with high quality.展开更多
Tadpole-shaped Au nano-particles with controllable tails are successfully fabricated by simply using laser fragmentation of separated Au nano-spheres in liquid. The optimum laser power densities（1.5–3 GW∕cm-2） can...Tadpole-shaped Au nano-particles with controllable tails are successfully fabricated by simply using laser fragmentation of separated Au nano-spheres in liquid. The optimum laser power densities（1.5–3 GW∕cm-2） can enable part of the individual Au nano-sphere to be re-melted, released, and ultra-rapidly recondensed/crystallized on the outside of the original region. We find that the length of the tail in a tadpole-shaped Au nano-particle significantly increases from about 10 to 25 nm by increasing the laser power density. Benefiting from the unique structural features, the localized surface plasmon resonance（LSPR） absorption spectra of the tadpole-shaped Au nano-particles become broader by increasing the tail length. Moreover, the LSPR absorption band also exhibits a noticeable red shift from about 520 to 650 nm. Our results provide a convenient and valuable strategy to fabricated novel anisotropic-shaped nano-structures with fascinating properties.展开更多
基金Financial support from the following projects and organisa- tions are acknowledged： the China One Thousand Talent Scheme, the National Natural Science Foundation of China （NNSFC） under its Major Research Scheme of Meso-scale Mechanism and Control in Multi-phase Reaction Processes （project reference： 91434126）, the Natural Science Foundation of Guangdong Province （project reference： 2014A030313228）, the UK Engineering and Physical Sciences Research Council （EPSRC） for the projects of Shape （EP/C009541） and StereoVision （EP/E045707）, and the Technology Strategy Board （TSB） for the project of High Value Manufacturing CGM （TP/BD059E）.
文摘Crystal morphology is known to be of great importance to the end-use properties of crystal products, and to affect down-stream processing such as filtration and drying. However, it has been previously regarded as too challenging to achieve automatic closed-loop control. Previous work has focused on controlling the crystal size distribution, where the size of a crystal is often defined as the diameter of a sphere that has the same volume as the crystal. This paper reviews the new advances in morphological population balance models for modelling and simulating the crystal shape distribution （CShD）, measuring and estimating crystal facet growth kinetics, and two- and three-dimensional imaging for on-line characterisation of the crystal morphology and CShD. A framework is presented that integrates the various components to achieve the ultimate objective of model-based closed-loop control of the CShD. The knowledge gaps and challenges that require further research are also identified.
文摘采用苦味酸和氨水制备出不敏感单质炸药苦味酸铵(C_6H_2(NO_2)_3ONH_4)。在此基础上研究晶形控制剂聚乙烯醇对苦味酸铵形貌及性能的影响,用SEM、XRD、DSC对其进行分析,并测试其撞击感度。结果表明:晶形控制的苦味酸铵性能有很大改观,其为粒径0.5μm的类球形,X射线的衍射角和特征峰没有变化,较原样品表观活化能提高4.701 k J·mol-1,热爆炸临界温度提高13.63℃,特征落高(H50)提高7.25%。研究表明通过晶形控制的苦味酸铵更钝感,具有较好的热安定性。
基金Natural Science Foundation for Key Program( 50935007 ) Natural Science Foundation (50805121)+3 种基金 National Basic Research Program of China (2010CB731701)Foundation for Fundamental Research of Northwestern Polytechnical University in PR China (NPU-FFR-JC20100229)Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University in PR China (27-TZ-2010 ) the 111 Project (B08040)
文摘用苦味酸和氨水制备不敏感单质炸药苦味酸铵。在此基础上研究不同晶形控制剂对结晶因素的分析,通过正交实验设计确定了优化晶形控制工艺条件,得到四种不同晶形的样品。采用显微镜、XRD对其进行表征,并对撞击感度和真空安定性进行测试。结果表明:晶形控制剂加入使所得晶体形貌规整、趋于棒状,X射线特征峰强度略有不同,添加3 m L 8%PVP制备晶体的撞击感度和真空安定性最优。
文摘Hierarchical structures, in which structure is generated and controlled simultaneously at different size scales, have attracted increasing attention due to their potentials in both theoretical research and practical applications. In this review, a "non-classical crystallization" mechanism is discussed for their possibilities in morphology control of hierarchically-structured materials. Differently, this crystallization route is not based on the attaching and detaching of monomers as happened in the classical case, but through the self-organization of preformed building blocks as nanosized subunits, whose oriented attachment leads to mesocrystals with favorable morphology and texture. Representative materials including both inorganic and organic crystals are reported with possible mechanisms proposed. Synthetic protocols based on this mechanism provide unique inspirations for materials design and could be applied to morphological and structural control of new materials with optimized functions.
基金supported by the National Natural Science Foundation of China (21175126)
文摘This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal nanocrystals. The seed-mediated growth method has become one of the most efficient and versatile methods for synthe-sizing high-quality noble metal nanocrystals. The seed-mediated growth method can separate the nucleation and growth stages of metal nanocrystals, and thus provide better control over the size, size distribution, and crystallographic evolution of metal nanocrystals. Because of its high controllability, the seed-mediated growth method is especially promising in providing mechanistic insights into the growth mechanisms of noble metal nanocrystals. In this review, the thermodynamic and kinetic parameters for the nucleation and growth of noble metal nanocrystals are systematically summarized. Mechanistic understanding of these parameters is provided. These studies provide useful guidelines for the rational design and synthesis of novel noble metal nanocrystals with high quality.
基金supported by the National Natural Science Foundation of China(Nos.11575102,11105085,and 11375108)the Fundamental Research Funds of Shandong University,China(No.2015JC007)
文摘Tadpole-shaped Au nano-particles with controllable tails are successfully fabricated by simply using laser fragmentation of separated Au nano-spheres in liquid. The optimum laser power densities（1.5–3 GW∕cm-2） can enable part of the individual Au nano-sphere to be re-melted, released, and ultra-rapidly recondensed/crystallized on the outside of the original region. We find that the length of the tail in a tadpole-shaped Au nano-particle significantly increases from about 10 to 25 nm by increasing the laser power density. Benefiting from the unique structural features, the localized surface plasmon resonance（LSPR） absorption spectra of the tadpole-shaped Au nano-particles become broader by increasing the tail length. Moreover, the LSPR absorption band also exhibits a noticeable red shift from about 520 to 650 nm. Our results provide a convenient and valuable strategy to fabricated novel anisotropic-shaped nano-structures with fascinating properties.
