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Preface to the“Theory and Applications of Flexoelectricity”Special Issue of Acta Mechanica Solida Sinica

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Acta Mechanica Solida Sinica 2024年第4期37卷 519-520页

作者： qian deng Yue Zheng Shengping Shen School of Aerospace Engineering Huazhong University of Science and TechnologyWuhan430074China School of Physics Sun Yat-sen UniversityGuangzhou510275China School of Aerospace Engineering Xi’an Jiaotong UniversityXi’an710049China

Flexoelectricity refers to the electric polarization generated by non-uniform mechanical strains within dielectric materials and *** intriguing effect bridges the fields of materials science,mechanical engineering,and applied physics,offering a promising avenue for innovation in sensor technology,energy harvesting,multiphysics field coupling,among others.

关键词： offering bridges harvesting

Electro-mechanical coupling properties of band gaps in an with periodically attached “spring-mass” resonators

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Applied Mathematics(A Journal of Chinese Universities) 2023年第3期38卷 429-443页

作者： ZHANG Jian qian deng-hui REN Long WANG Qi School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China China Nanhu Academy of Electronics and Information Technology Jiaxing 314000China

The model of a locally resonant (LR) epoxy/PZT-4 phononic crystal (PC)nanobeam with “spring-mass” resonators periodically attached to epoxy is proposed. The corresponding band structures are calculated by coupling Euler beam theory, nonlocal piezoelectricity theory and plane wave expansion (PWE) method. Three complete band gaps with the widest total width less than 10GHz can be formed in the proposed nanobeam by comprehensively comparing the band structures of three kinds of LR PC nanobeams with resonators attached or not. Furthermore, influencing rules of the coupling fields between electricity and mechanics,“spring-mass” resonator, nonlocal effect and different geometric parameters on the first three band gaps are discussed and summarized. All the investigations are expected to be applied to realize the active control of vibration in the region of ultrahigh frequency.

关键词： phononic crystal nanobeam electro-mechanical coupling effect nonlocal effect locally resonant mechanism

Heterologous expression of Avermectins biosynthetic gene cluster by construction of a Bacterial Artificial Chromosome library of the producers

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Synthetic and Systems Biotechnology 2017年第1期2卷 59-64页

作者： qian deng Li Zhou Meizhong Luo Zixin deng Changming Zhao Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Educationand School of Pharmaceutical SciencesWuhan UniversityWuhan430071China College of Life Science and Technology Huazhong Agricultural UniversityWuhan430073China

Avermectins,a group of polyketide natural products,are widely used as anthelmintics in *** engineering and combinatorial biosynthesis were extensively employed to improve Avermectins production and create novel Avermectin derivatives,including Ivermectin and *** is labor intensive and time cost to genetically manipulate Avermectins producer Streptomyces avermitilis in *** and heterologous expression of Avermectins biosynthetic gene cluster will make it possible to tailor the cluster in *** constructed a Bacterial Artificial Chromosome(BAC)library of *** ATCC 31267 with inserted DNA fragments ranged from 100 to 130 *** recombinant BAC clones which carried the Avermectins biosynthetic gene cluster ave(81 Kb in size)were screened out from the ***,ave was hetero-expressed in *** Avermectin components,A2a,B1a and A1a were detected from the cell extracts of recombinant *** will facilitate the development of Avermectin derivatives by polyketide synthase domain swapping and provide functional element for Avermectins synthetic biology study.

关键词： Streptomyces Avermectin BAC library Heterologous expression

A Modified Fuzzy C-Means Algorithm for Brain MR Image Segmentation and Bias Field Correction

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Journal of Computer Science & Technology 2016年第3期31卷 501-511页

作者： Wen-qian deng Xue-Mei Li Xifeng Gao Cai-Ming Zhang School of Computer Science and Technology Shandong University Jinan 250101 China Department of Computer Science University of Houston Houston TX 77004 U.S.A.

In quantitative brain image analysis, accurate brain tissue segmentation from brain magnetic resonance image （MRI） is a critical step. It is considered to be the most important and difficult issue in the field of medical image processing. The quality of MR images is influenced by partial volume effect, noise, and intensity inhomogeneity, which render the segmentation task extremely challenging. We present a novel fuzzy c-means algorithm （RCLFCM） for segmentation and bias field correction of brain MR images. We employ a new gray-difference coefficient and design a new impact factor to measure the effect of neighbor pixels, so that the robustness of anti-noise can be enhanced. Moreover, we redefine the objective function of FCM （fuzzy c-means） by adding the bias field estimation model to overcome the intensity inhomogeneity in the image and segment the brain MR images simultaneously. We also construct a new spatial function by combining pixel gray value dissimilarity with its membership, and make full use of the space information between pixels to update the membership. Compared with other state-of-the-art approaches by using similarity accuracy on synthetic MR images with different levels of noise and intensity inhomogeneity, the proposed algorithm generates the results with high accuracy and robustness to ***.

关键词： image segmentation fuzzy c-means bias field correction anti-noise

Distribution and geochemical significance of trace elements in kerogens from Ediacaran–Lower Cambrian strata in South China

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Acta Geochimica 2023年第1期42卷 50-62页

作者： qian deng Guanyu Zhao Haozhe Wang Bin Cheng Zewen Liao State Key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China CAS Center for Excellence in Deep Earth Science Guangzhou 510640China University of Chinese Academy of Sciences Beijing 100049China

Some trace elements(TEs),both bio-essential and redox-sensitive,are promising tracers of Earth’s surface *** an essential sedimentary organic matter,kerogen may have inherited and retained the key TEs from *** this study,the distribution of TEs in kerogens from two sections(Dongkanshang and Fengtan) in South China was analyzed to explore its biogeochemical significance during Ediacaran-Lower *** with V and Zn,the relative concentrations of Co,Ni,Cu,and Mo were generally higher in kerogens than in the whole *** of TEs in the kerogen was involved in the selective utilization of TEs by different organic precursors and the competition of sulfide in the depositional *** significant content of TEs in the kerogens from deep-water facies corresponded to a more negative δ^(13) Ckeras a result of the dominant taxa of chemo autotrophs with tremendous bioaccumulation potential for trace metals and the reduction conditions favorable for organic matter ***,the content variations of trace elements in the kerogens coincided with the rise and fall of the Ediacaran biota,implying that the trace elements might have played an important role in early life evolution.

关键词： Trace elements Kerogen Ediacaran-Early Cambrian Biogeochemical significance South China

Simulation of epitaxial growth on convex substrate using phase field crystal method

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Frontiers of Materials Science 2014年第2期8卷 185-192页

作者： Ying-Jun GAO Li-Lin HUANG qian-qian deng Kui LIN Chuang-Gao HUANG College of Physical Science and Engineering Guangxi University Nanning 530004 China Ministry Key Laboratory for Non-Ferrous Metal and Featured Materials Nanning 530004 China

Phase field crystal （PFC） model is employed to simulate the process of growth of epitaxial layer on plane-convex substrate with a lattice mismatch and a small inclination angle. The variation of the systematic free energy, the total atomic number of the epitaxial layer, and the effect of the curvature and the angle of the substrate are analyzed. The results show that when the surface of the substrate is plane, the free energy increases with the increase of the substrate inclination angle, and also the total atomic number of the epitaxial layer increases; while the surface of the substrate is convex, the free energy decreases with the increase of substrate angle and so also the total atomic number of the epitaxial layer decrease. This is the reason that the frontier of surface of epitaxial layer changes from the step bunching to the hill-and-valley facet structure with the increasing of the inclination angle of convex substrate. These results are in good agreement with the other method results.

关键词： heteroepitaxy phase field crystal (PFC) convex substrate atomic number

Modes of grain growth and mechanism of dislocation reaction under applied biaxial strain:Atomistic and continuum modeling

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Journal of Materials Science & Technology 2020年第14期47卷 236-250页

作者： Ying-Jun Gao qian-qian deng Zhe-yuan Liu Zong-Ji Huang Yi-Xuan Li Zhi-Rong Luo Guangxi Advanced Key Laboratory of Novel Energy Materials Guangxi Key Laboratory for the Relativistic AstrophysicsSchool of Physics Science and EngineeringGuangxi UniversityNanning530004China Institute of Physics Science and Engineering Technology Yulin Normal UniversityYulin537000China

The phase field crystal method and Continuum Modeling are applied to study the cooperative dislocation motion of the grain boundary(GB)migration,the manner of the nucleation of the grain and of the grain growth in two dimensions(2 D)under the deviatoric deformation at high *** types of the nucleation modes of new finding are observed by the phase field crystal simulation:The first mode of the nucleation is generated by the GB splitting into two sub-GBs;the second mode is of the reaction of the sub-GB dislocations,such as,the generation and annihilation of a pair of partial Frank sessile dislocation in 2 *** process can be considered as the nucleation of dynamic recrystallization;the third mode is caused by two oncoming rows of the dislocations of these sub-GBs,crossing and passing each other to form new gap which is the nucleation place of the new deformed *** research is shown that due to the nucleation of different modes the mechanism of the grain growth by means of the sub-GB migration is different,and therefore,the grain growth rates are also *** the deviatoric deformation of the applied biaxial strain,the grain growth is faster than that of the grain growth without external applied *** is observed that the cooperative dislocation motion of the GB migration under the deviatoric deformation accompanies with local plastic flow and the state of the stress of the system changes *** the system is in the process of recrystallized grain growth,the system energy is in an unstable state due to the release of the strain energy to cause that the reverse movement of the plastic flow *** area growth of the deformed grain is approximately proportional to the strain square and also to the time *** rule of the time square of the deformed grain growth can also be deduced by establishing the continuum dynamic equation of the biaxial strain-driven migration of the *** copper metal is taken as an example of the calcu

关键词： Grain boundary splitting Grain growth Dislocation reaction Atomistic simulation Continuum modeling

Streptomyces avermitilis industrial strain as cell factory for Ivermectin B1a production

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Synthetic and Systems Biotechnology 2019年第1期4卷 34-39页

作者： qian deng Liqiongzi Xiao Yang Liu Lixin Zhang Zixin deng Changming Zhao Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of EducationSchool of Pharmaceutical SciencesWuhan UniversityWuhanChina State Key Laboratory of Bioreactor Engineering East China University of Science and TechnologyShanghaiChina

Ivermectin,a kind of valuable derivatives of Avermectin,is distinct from Avermectin due to the saturated bond at C22eC23 *** biosynthesis of Ivermectins based on Avermectins biosynthetic gene cluster(ave)has been achieved recently,while the establishment of an Ivermectin homogeneous component producing strain is challenging because of the limited compatibility between the native and heterologous polyketide synthase(PKS)*** this study,the PKS module 2 Dehydratase(DH)-Enoylreductase(ER)-Ketoreductase(KR)domain set of Meilingmycin,which is another naturally occurring homologue of Avermectin,was employed to substitute the DH-KR domains of Avermectins PKS module 2 to generate an Ivermectin biosynthetic gene cluster(ive).Ivermectins B1a and A1a were heterologously biosynthesized in a classic actinomyces host Streptomyces *** Avermectin B1a high-producing strain *** 3-115 was genetically engineered to give an artificial host cell and Ivermectin B1a single component was effectively produced with a production of 1.25±0.14 g/L.

关键词： Avermectin Ivermectin Meilingmycin Domain swapping Heterologo-us biosynthesis

Rapid determination of pharmaceuticals from multiple therapeutic classes in wastewater by solid-phase extraction and ultra-performance liquid chromatography tandem mass spectrometry

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Chinese Science Bulletin 2009年第24期54卷 4633-4643页

作者： SUI qian HUANG Jun deng ShuBo YU Gang POPs Research Centre Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China

A new analytical method utilizing ultra-performance liquid chromatography (UPLC) tandem mass spectrometry (MS/MS) has been developed to determine 16 pharmaceuticals from 8 therapeutic classes in wastewater: bezafibrate, clofibric acid, carbamazepine, caffeine, chloramphenicol, diclofenac, gemfibrozil, indomethacin, ketoprofen, mefenamic acid, metoprolol, nalidixic acid, N,N-diethyl-metatoluamide, propranolol, sulpiride and trimethoprim. Key parameters of MS/MS, UPLC and solid phase extraction (SPE) were optimized. In general, recovery of target pharmaceuticals was over 70% for the wastewater effluent samples and 50% for the influent samples. The effects of matrix suppression, loss during the pretreatment as well as instrument variability were successfully corrected by two internal standards, and acceptable relative recovery was obtained. Target compounds were quantitatively analyzed using multiple reaction monitoring (MRM) mode, and the detection limits ranged from 0.3 to 20 ng/L. A detailed study, matrix effect in effluent wastewater was also present. The method was applied to detecting pharmaceuticals in the wastewater from three wastewater treatment plants (WWTPs) in Beijing, China and the results demonstrated that most target compounds were detectable in both the influent and effluent, with the mean concentrations ranging from 20.5 to 5775.6 ng/L and 4.6 to 418.6 ng/L, respectively.

关键词：高效液相色谱串联质谱法固相萃取废水药品快速测定治疗污水处理厂