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Transient flameout process of boron-magnesium agglomerates during combustion in oxygen-rich atmospheres

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Particuology 2024年第5期88卷 290-301页

作者： Lian Duan Zhixun Xia Yunchao Feng Binbin Chen Likun ma jianxin Hu College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China School of Mechanical Engineering and Mechanics Xiangtan UniversityXiangtan 411105China

In this study,boron–magnesium agglomerates with varying mass ratios were prepared by drying a micron-sized boron–magnesium mixed suspension,and the combustion process of these agglomerates under different oxygen-rich concentrations were investigated using a laser ignition system.The test results showed that when the mass fraction of magnesium powder in boron-magnesium agglomerates exceeded a certain threshold(between 2%and 5%),flame extinction and reignition occurred after a significant reduction in the agglomerate volume during combustion.This process is referred to as the transient flameout process,which is affected by the magnesium content of the agglomerate and the oxygen concentration in the ambient atmosphere.An increase in the magnesium content or oxygen concentration makes this phenomenon more pronounced.During weakening of the flame intensity,a dark film gradually covered the particle surfaces.X-ray diffraction and elemental analyses of the cross-section and outer surface of the condensed combustion product suggested that the dark film is primarily composed of Mg-B-O ternary oxides.This film prevents direct contact between boron and oxygen,thereby inhibiting surface and gas-phase reactions and leading to the occurrence of the transient flameout phenomenon.

关键词： Agglomerated particle Boron–magnesium fuel Boron combustion Transient flameout process Solid fuel ramjet

Dynamic threshold for SPWVD parameter estimation based on Otsu algorithm

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Journal of Systems Engineering and Electronics 2013年第6期24卷 919-924页

作者： Ning ma jianxin Wang School of Electronic Engineering and Optoelectronic Technology Nanjing University of Science and Technology

Time-frequency-based methods are proven to be effective for parameter estimation of linear frequency modulation （LFM） signals. The smoothed pseudo Winger-Ville distribution （SPWVD） is used for the parameter estimation of multi-LFM signals, and a method of the SPWVD binarization by a dynamic threshold based on the Otsu algorithm is proposed. The proposed method is effective in the demand for the estimation of different parameters and the unknown signal-to-noise ratio （SNR） circumstance. The performance of this method is confirmed by numerical simulation.

关键词： parameter estimation smoothed pseudo Winger-Ville distribution （SPWVD） dynamic threshold Otsu algorithm

A Post-domestication Mutation, Dt2, Triggers Systemic Modification of Divergent and Convergent Pathways Modulating Multiple Agronomic Traits in Soybean

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Molecular Plant 2019年第10期12卷 1366-1382页

作者： Dajian Zhang Xutong Wang Shuo Li Chaofan Wang Michael JGosney Michael VMickelbart Jianxin Ma Department of Agronomy Purdue UniversityWest LafayetteIN 47907USA College of Agronomy Shandong Agricultural UniversityTai'anShandong 271018China School of Life Sciences Shandong UniversityQingdaoShandong 266237China Department of Botany and Plant Pathology Purdue UniversityWest LafayetteIN 47907USA Center for Plant Biology Purdue UniversityWest LafayetteIN 47907USA

The semi-determinate stem growth habit in leguminous crops,similar to the“green revolution”semi-dwarf trait in cereals,is a key plant architecture trait that affects several other traits determining grain yield.In soybean semi-determinacy is modulated by a post-domestication gain-of-function mutation in the gene,Dt2,which encodes an maDS-box transcription factor.However,its role in systemic modification of stem growth and other traits is unknown.In this study,we show that Dt2 functions not only as a direct repressor of Dt1,which prevents terminal flowering,but also as a direct activator of putative floral integrator/identity genes including GmSOC1,GmaP1,and GmFUL,which likely promote flowering.We also demonstrate that Dt2 functions as a direct repressor of the putative drought-responsive transcription factor gene GmDREB1D,and as a direct activator of GmSPCH and GmGRP7,which are potentially associated with asymmetric division of young epidermal cells and stomatal opening,respectively,and may affect the plant's water-use efficiency(WUE).Intriguingly,Dt2 was found to be a direct activator or repressor of the precursors of eight microRNAs targeting genes potentially associated with meristem maintenance,flowering time,stomatal density,WUE,and/or stress responses.This study thus reveals the molecular basis of pleiotropy associated with plant productivity,adaptability,and environmental resilience.

关键词： abiotic stress agronomic traits convergent pathways stem growth habit pleiotropy soybean

Multi-functional Photoelectric Sensor Based on a Three-fold Interpenetrated Cd(II)Coordination Polymer for Sensitive Detecting Different Ions

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Chemical Research in Chinese Universities 2022年第4期38卷 1105-1110页

作者： WANG Yue WANG Jinling ma jianxin ZHANG Yue XU Na WANG Xiuli Professional Technology Innovation Center of Liaoning Province for Conversion materials of Solar Cell College of Chemistry and Materials EngineeringBohai UniversityJinzhou121013P.R.China

Athree-fold interpenetrated cadmium coordination polymer[Cd_(3)(BTC)_(2)(H_(2)O)_(9)]·2H_(2)O(CP 1)(H_(3)BTC=1,3,5-benzenetricarboxylic acid)was selected and synthesized to investigate its photoelectric properties.CP 1 showed excellent sensitivity for Cr_(2)O_(7)^(2−)and Fe^(3+),low limit of detection(LOD:0.39µmol/L for Cr_(2)O_(7)^(2−)and 1.72µmol/L for Fe^(3+))and stability as electrochemical sensor.More importantly,fluorescence sensing studies indicated that CP 1 exhibits sensing activity for Fe^(3+),Fe^(2+),and MnO_(4)−with good cyclic stability and selectivity.Low LOD and high-sensitivity capability of CP 1 make it a potential multifunctional photoelectric sensor.

关键词： Coordination polymer Photoelectric sensor Electrochemistry sensing Fluorescence sensing Cr_(2)O_(7)^(2−)and MnO_(4)^(−)

Intelligent self-assembly prodrug micelles loading doxorubicin in response to tumor microenvironment for targeted tumors therapy

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Chinese Journal of Chemical Engineering 2021年第11期34卷 219-227页

作者： Dong Wan Sunfan Li jianxin Zhang Guilei ma Jie Pan School of Chemistry and Chemical Engineering Tiangong UniversityTianjin 300387China The Tianjin Key Laboratory of Biomaterials Institute of Biomedical EngineeringPeking Union Medical College&Chinese Academy of Medical SciencesTianjin 300192China

Compared with physical drug-loaded nanocarriers,polymeric prodrug micelles have many advantages such as high drug loading and enhanced stability in blood,so they have great potential in cancer therapy.However,these micelles have a big disadvantage,which cannot achieve long-term circulation in vivo and high absorption of tumor cells simultaneously,resulting in low administration efficiency and poor therapeutic effect on cancer.To solve problems of traditional polymeric prodrug micelles,novel polymeric micelles with tumor microenvironment response were designed in this work.The prodrug formed by covalently linking D-α-tocopherol polyethylene glycol succinate(TPGS_(3350)),peptide(Pep),and doxorubicin(DOX)(TPGS_(3350)-Pep-DOX)was self-assembled into micelles by encapsulating DOX physically.When the micelles entered the tumor tissue,the long-chain polyethylene glycol(PEG)was sensitively cut by the matrix metalloproteinase 2/9(MMP2/9)enzyme,exposing the targeting molecule folate,then it entered the cell through the endocytic pathway mediated by the folate receptor.The drug loading content,encapsulation efficiency,critical micelle concentration,and invitro release of the micelles invented in this study were measured to characterize their properties.The particle size and zeta potential of micelles were characterized by dynamic light scattering.Images were scanned by transmission electron microscopes.In vitro cytotoxicity,cellular uptake,and in vivo antitumor effect evaluation experiments were measured to show that smart micelles have made much progress in material chemistry and drug delivery,making it possible to apply a stimulus-response carrier drug delivery system in clinical application.

关键词： Micelles Drug delivery Tumor Enzyme Polymers Peptide

A Hybrid Algorithm Based on Binary Chemical Reaction Optimization and Tabu Search for Feature Selection of High-Dimensional Biomedical Data

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Tsinghua Science and Technology 2018年第6期23卷 733-743页

作者： Chaokun Yan Jingjing ma Huimin Luo jianxin Wang the School of Computer and Information Engineering Henan UniversityKaifeng 475000 China School of Information Science and Engineering Central South University Changsha 410083 China

In recent years, there have been rapid developments in various bioinformatics technologies, which have led to the accumulation of a large amount of biomedical data. The biomedical data can be analyzed to enhance assessment of at-risk patients and improve disease diagnosis, treatment, and prevention. However, these datasets usually have many features, which contain many irrelevant or redundant information. Feature selection is a solution that involves finding the optimal subset, which is known to be an NP problem because of the large search space. Considering this, a new feature selection approach based on Binary Chemical Reaction Optimization algorithm （BCRO） and k-Nearest Neighbors （KNN） classifier is presented in this paper. Tabu search is integrated with CRO framework to enhance local search capacity. KNN is adopted to evaluate the quality of selected candidate subset. The results for an experiment conducted on nine standard medical datasets demonstrate that the proposed approach outperforms other state-of-the-art methods.

关键词： feature selection biomedical data chemical reaction optimization tabu search

An Event-Triggered Energy-Efficient Clustering in Collaborative Beamforming for Wireless Sensor Networks

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Journal of Harbin Institute of Technology(New Series) 2016年第5期23卷 8-14页

作者： Jianxin Ma Shuo Shi Si Tian Xuemai Gu Communication Research Centre Harbin Institute of Technology

In this paper,we present a protocol,CEWEC(Collaborative,Event-Triggered,Weighted,EnergyEfficient Clustering),based on collaborative beamforming.It is designed for wireless sensor nodes to realize the long-distance transmission.In order to save the energy of sensor nodes,a node wakes up when it has data to be uploaded.In our protocol,multi-layer structure is adopted: trigger-node layers,clusterhead-node layers,childnode layers.The number of child nodes and clusterheads depends on the distance of transmission.Clusterheads are selected according to the node's weight which is based on its residual energy and distance to the trigger node.The main characteristic of this protocol is that clusterheads can directly communication with each other without the large-scale base station and antennas.Thus,the data from the trigger node would be able to be shared within the multi-layer structure.Considering the clustering process,energy model,and success rate,the simulation results show that the CEWEC protocol can effectively manage a large number of sensor nodes to share and transmit data.

关键词： Sensor networks clustering collaborative beamforming energy efficiency network lifetime

Catalytic Enantioselective Simultaneous Control of Axial Chirality and Central Chirality in Allenes

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Chinese Journal of Chemistry 2018年第5期36卷 387-391页

作者： jianxin Dai Xinyu Duan Jing Zhou Chunling Fu Shengming ma Laboratory of MolecuJar Recognition and Synthesis Department of Chemistry Zhejian8 University Hangzhou Zhejiang 310027 China

Chiral molecules, which may contain one or more different type（s） of stereocentres, such as central, axial, planar, and helical chiralities, etc., are indispensable in chemistry, pharmaceutical industry, and life science. Despite many advances for the preparation of chiral molecules usually with a single type of chirality have been realized, simultaneous construction of different types of chiralities is still a significant challenge. Here, we wish to report a protocol for preparation of chiral allenes with both central and axial chiralities via a catalytic asymmetric allenylation of different biologically or syn- thetically useful fluorinated or non-fluorinated nucleophiles with readily available racemic allenes by using a single chiral ligand. An echoing between the central chirality and axial chirality for the enantioselectivity was observed. This strategy provides a general and practical approach to functionalized optically active allenes bearing both central and axial chiralities with an excellent enantioselectivity under mild conditions.

关键词： chiral palladium catalysis axial chirality central chirality simultaneous control allene

Origin of Boron in the Gas Hure Salt Lake of Northwestern Qaidam Basin, China: Evidence from Hydrochemistry and Boron Isotopes

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Acta Geologica Sinica(English Edition) 2021年第2期95卷 531-540页

作者： HAN Jibin XU jianxin Syed Asim HUSSAIN JIANG Hongchen ma Yunqi XU Kai ma Haizhou Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Qinghai Institute of Salt LakesChinese Academy of SciencesXining 810008China Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes Xining 810008China Department of Earth Sciences Karakoram International UniversityGilgitGilgit-Baltistan 15100Pakistan State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China

The Gas Hure Salt Lake(GHSL) in the northwestern Qaidam Basin, western China, is rich in boron(B) resources, but its B-resource origin is hardly known. Hydrochemical compositions and B isotope characteristics of different waters were collected around the GHSL, including the river water, stream water, spring water, salt-lake brine, intercrystalline brine, well water, drilling brine, and solar pond brine. The hydrochemical signatures suggest that silicates, carbonates and evaporates are the main B-bearing rocks during the water dynamic. The reservoir estimation of B resources shows that the Kulamulekesay River(KLMR) and the Atekan River(ATKR) contribute annually 18.3 tons and 22.84 tons of B, respectively, with a total amount of 11.72 × 10^(4) tons of B during the past 5.7 ka. In comparison with the known B reservoir(32.96 × 10^(4) tons) in the GHSL, a significant amount of B in the GHSL was probably recharged from deep fluids and sediments around the GHSL. The B concentration and B-enrichment degree are shaped by the evaporation process, which are highly elevated at the carnallite and bischofite stages.

关键词： B-bearing rock weathering evaporation process Holocene Qinghai and Xinjiang provinces