30 research outputs found

    Kropina metrics with isotropic scalar curvature

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    In this paper, we study Kropina metrics with isotropic scalar curvature. First, we obtain the expressions of Ricci curvature tensor and scalar curvature. Then, we characterize the Kropina metrics with isotropic scalar curvature on by tensor analysis

    Dendronized CarbohydratesⅡ—Liquid Crystallinity Study

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    Compartmentalized Thin Films with Customized Functionality via Interfacial Cross-linking of Protein Cages

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    Hybrid thin films with a high loading and homogeneous dispersion of functional nanoparticles (and/or molecules) find applications in (bio)-sensors and electronic devices. The fabrication of such hybrid thin films, however, suffers from the complex and diverse surface and physicochemical properties of individual nanoparticles. To address this challenge, a facile and general strategy toward compartmentalized thin films through the interfacial cross-linking of viral protein cages is reported. Employing these protein cages, gold nanoparticles, as well as enzyme horseradish peroxidase, are encapsulated into virus-like particles and then cross-linked into thin films with a thickness varying from monolayer to submicron dimensions. These compartmentalized thin films not only ensure that the cargo is homogeneously dispersed, but also display good catalytic activity. This strategy is, in principle, applicable for a wide range of (bio)-organic nanocontainers, enabling the versatile fabrication of 2D thin films with extensive application prospects.</p

    Compartmentalized supramolecular hydrogels based on viral nanocages towards sophisticated cargo administration

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    Introduction of compartments with defined spaces inside a hydrogel network brings unique features, such as cargo quantification, stabilization and diminishment of burst release, which are all desired for biomedical applications. As a proof of concept, guest-modified cowpea chlorotic mottle virus (CCMV) particles and complementary guest-modified hydroxylpropyl cellulose (HPC) were non-covalently cross-linked through the formation of ternary host-guest complexes with cucurbit[8]uril (CB[8]). Furthermore, CCMV based virus-like particles (VLPs) loaded with tetrasulfonated zinc phthalocyanine (ZnPc) were prepared, with a loading efficiency up to 99%, which are subsequently successfully integrated inside the supramolecular hydrogel network. It was shown that compartments provided by protein cages not only help to quantify the loaded ZnPc cargo, but also improve the water solubility of ZnPc to avoid undesired aggregation. Moreover, the VLPs together with ZnPc cargo can be released in a controlled way without an initial burst release. The photodynamic effect of ZnPc molecules was retained after encapsulation of capsid protein and release from the hydrogel. This line of research suggests a new approach for sophisticated drug administration in supramolecular hydrogels.</p

    Addition of alkynes and osmium carbynes towards functionalized dπ-pπ conjugated systems

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    碳-碳三键和碳-金属三键是两类高度不饱和的化学键。该工作发现了这两类三键之间的全新反应模式。利用该反应能把金属和有机π共轭体系有效结合,得到一类金属d轨道参与π共轭的全新大π共轭体系。化学化工学院夏海平教授课题组碳龙化学研究取得新进展,利用金属卡拜与炔烃的新反应,成功地合成了一类金属d轨道参与π共轭的全新共轭体系并在有机太阳能电池领域得到应用。该工作是在夏海平教授和南方科技大学何凤副教授共同指导下完成的。化学化工学院2016级iChEM博士生陈仕焰和南科大博士生刘龙珠为论文的共同第一作者。该工作充分体现了多学科协同创新研究优势:相关化合物合成、表征由陈仕焰、高翔、彭丽霞、张颖等完成;光电测试由刘龙珠完成;理论计算由陈仕焰、华煜晖完成。化学化工学院杨柳林副教授、谭元植教授等对研究工作给予了大力支持。【Abstract】The metal-carbon triple bonds and carbon-carbon triple bonds are both highly unsaturated bonds. As a result, their reactions tend to afford cycloaddition intermediates or products. Herein, we report a reaction of M≡C and C≡C bonds that affords acyclic addition products. These newly discovered reactions are highly efficient, regio- and stereospecific, with good functional group tolerance, and are robust under air at room temperature. The isotope labeling NMR experiments and theoretical calculations reveal the reaction mechanism. Employing these reactions, functionalized dπ-pπ conjugated systems can be easily constructed and modified. The resulting dπ-pπ conjugated systems were found to be good electron transport layer materials in organic solar cells, with power conversion efficiency up to 16.28% based on the PM6: Y6 non-fullerene system. This work provides a facile, efficient methodology for the preparation of dπ-pπ conjugated systems for use in functional materials.This research was supported by the National Natural Science Foundation of China (Nos. U1705254, 21931002, and 21975115), Guangdong Provincial Key Laboratory of Catalysis (No. 2020B121201002), Shenzhen Nobel Prize Scientists Laboratory Project (no.C17783101), and the National Key R&D Program of China (2017YFA0204902). We thank the SUSTech Core Research Facilities for the Holiba-UVISEL measurements. 研究工作得到了国家自然科学基金(U1705254、21931002、21975115),广东省催化化学重点实验室(No. 2020B121201002),国家重点研发计划(2017YFA0204902),及深圳诺贝尔奖科学家实验室(C17783101)等项目资助

    Immobilization of Catalytic Virus-like Particles in a Flow Reactor

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    A functional microfluidic reactor is constructed by immobilization of gold containing virus-based protein cages that reduce nitro-arenes with high efficiency

    Modeling and Parameter Identification of a 3D Measurement System Based on Redundant Laser Range Sensors for Industrial Robots

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    The low absolute positioning accuracy of industrial robots is one of the bottlenecks preventing industrial robots from precision applications. Kinematic calibration is the main way to improve the absolute positioning accuracy of industrial robots, which greatly relies on three-dimensional (3D) measurement instruments, including laser trackers and pull rope mechanisms. These instruments are costly, and their required intervisibility space is large. In this paper, a precision 3D measurement instrument integrating multiple laser range sensors is designed, which fuses the information of multiple redundant laser range sensors to obtain the coordinates of a 3D position. An identification model of laser beam position and orientation parameters based on redundant distance information and standard spherical constraint is then developed to reduce the requirement for the assembly accuracy of laser range sensors. A hybrid identification algorithm of PSO-LM (particle swarm optimization Levenberg Marquardt) is designed to solve the high-order nonlinear problem of the identification model, where PSO is used for initial value identification, and LM is used for final value identification. Experiments of identification of position and orientation, verifications of the measuring accuracy, and the calibration of industrial robots are conducted, which show the effectiveness of the proposed 3D measurement instrument and identification methods. Moreover, the proposed instrument is small in size and can be used in narrow industrial sites

    Modeling and Parameter Identification of a 3D Measurement System Based on Redundant Laser Range Sensors for Industrial Robots

    No full text
    The low absolute positioning accuracy of industrial robots is one of the bottlenecks preventing industrial robots from precision applications. Kinematic calibration is the main way to improve the absolute positioning accuracy of industrial robots, which greatly relies on three-dimensional (3D) measurement instruments, including laser trackers and pull rope mechanisms. These instruments are costly, and their required intervisibility space is large. In this paper, a precision 3D measurement instrument integrating multiple laser range sensors is designed, which fuses the information of multiple redundant laser range sensors to obtain the coordinates of a 3D position. An identification model of laser beam position and orientation parameters based on redundant distance information and standard spherical constraint is then developed to reduce the requirement for the assembly accuracy of laser range sensors. A hybrid identification algorithm of PSO-LM (particle swarm optimization Levenberg Marquardt) is designed to solve the high-order nonlinear problem of the identification model, where PSO is used for initial value identification, and LM is used for final value identification. Experiments of identification of position and orientation, verifications of the measuring accuracy, and the calibration of industrial robots are conducted, which show the effectiveness of the proposed 3D measurement instrument and identification methods. Moreover, the proposed instrument is small in size and can be used in narrow industrial sites

    Real Time Ultrasound-Guided Thoracic Epidural Catheterization with Patients in the Lateral Decubitus Position without Flexion of Knees and Neck: A Preliminary Investigation

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    Objectives: For some patients, such as pregnant women, it can be difficult to maintain the ideal &ldquo;forehead to knees&rdquo; position for several minutes for epidural catheter placement. We conducted this study to investigate the feasibility of real-time ultrasound-guided (US) epidural catheterization under a comfortable lateral position without flexion of knees and neck. Materials and Methods: 60 patients aged 18-80 years with a body mass index of 18-30 kg/m2 after general surgery were included. In a comfortable left lateral position, thoracic epidural catheterization was performed under real-time US for postoperative analgesia. The visibility of the neuraxial structures, procedural time from needle insertion to loss of resistance in the epidural space, the number of needle redirections, success rate of epidural catheter placement and postoperative analgesic effect were recorded. Results: In the paramedian oblique sagittal view, the well visible of vertebral lamina, intervertebral space and posterior complex under ultrasound were as high as 93.33%, 81.67% and 70.00%, respectively. The success rate of thoracic epidural catheterization was as high as 91.67%, and the satisfactory postoperative analgesic effect was 98.2% for patients without nausea, pruritus and other discomfort. Discussion: Thoracic epidural catheterization with patients in the lateral position without flexion of knees and neck under real time ultrasound guidance has a high success rate and strong feasibility. This visual manipulation makes epidural catheterization not only &ldquo;easier&rdquo; to perform, but also reduces the requirements of the procedure

    Compartmentalized Thin Films with Customized Functionality via Interfacial Cross-linking of Protein Cages

    No full text
    Hybrid thin films with a high loading and homogeneous dispersion of functional nanoparticles (and/or molecules) find applications in (bio)-sensors and electronic devices. The fabrication of such hybrid thin films, however, suffers from the complex and diverse surface and physicochemical properties of individual nanoparticles. To address this challenge, a facile and general strategy toward compartmentalized thin films through the interfacial cross-linking of viral protein cages is reported. Employing these protein cages, gold nanoparticles, as well as enzyme horseradish peroxidase, are encapsulated into virus-like particles and then cross-linked into thin films with a thickness varying from monolayer to submicron dimensions. These compartmentalized thin films not only ensure that the cargo is homogeneously dispersed, but also display good catalytic activity. This strategy is, in principle, applicable for a wide range of (bio)-organic nanocontainers, enabling the versatile fabrication of 2D thin films with extensive application prospects
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