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邻(对)氯苯甲醛生产工艺改进

云南化工 2024年第5期51卷 51-54页

作者：牛富强袁志明朱文浩罗卫湖北源洹实业投资有限公司湖北当阳444100

以邻(对)氯甲苯和氯气为原料,采用塔式氯化催化反应及精馏技术合成了邻(对)氯氯苄和邻(对)氯苄叉二氯。氯化液经碱洗、减压精馏制得邻(对)氯氯苄、邻(对)氯苄叉二氯,经水解、碱解、精制得到高纯度的邻(对)氯苯甲醛。此工艺克服了目前生... 详细信息

以邻(对)氯甲苯和氯气为原料,采用塔式氯化催化反应及精馏技术合成了邻(对)氯氯苄和邻(对)氯苄叉二氯。氯化液经碱洗、减压精馏制得邻(对)氯氯苄、邻(对)氯苄叉二氯,经水解、碱解、精制得到高纯度的邻(对)氯苯甲醛。此工艺克服了目前生产中催化剂活性不够、水解反应时间长、物料聚合严重、残液量大、水解收率偏低以及含大量有毒有害废液等问题,氯化反应收率可达98.0%以上,邻氯氯苄产品总收率大于92%,邻氯苯甲醛产品总收率大于92%,氯气利用率可达90.0%以上。与国内同行业相比,具有产品收率高,质量好,环境污染小等特点。

关键词：邻(对)氯苯甲醛邻(对)氯甲苯氯气

一种适用于被动声学监测系统的海豚回声定位信号快速检测方法

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声学技术 2023年第6期42卷 733-740页

作者：薛睿超牛富强自然资源部第三海洋研究所福建厦门361005 厦门海洋职业技术学院福建厦门361005

被动声学监测仪已成为海豚的声信号研究的重要手段。为解决监测系统计算速度慢、检测正确率低等问题,满足低功耗长期工作的需求,文章结合海豚回声定位信号的时域特征,提出了一种快速检测方法。该算法不需要进行快速傅里叶变换和频域分析... 详细信息

被动声学监测仪已成为海豚的声信号研究的重要手段。为解决监测系统计算速度慢、检测正确率低等问题,满足低功耗长期工作的需求,文章结合海豚回声定位信号的时域特征,提出了一种快速检测方法。该算法不需要进行快速傅里叶变换和频域分析,因此大大提高了计算速度并有效降低了系统算力需求,进而延长被动声监测系统的工作时间和提高工作效率。使用野外和室内采集的中华白海豚以及宽吻海豚声信号数据进行测试。测试结果表明,检测速度大幅提高,且检测正确率达到90%以上。

关键词：被动声学监测快速检测海豚回声定位信号 click信号特征

Vascularization ability of glioma stem cells in different three-dimensional microenvironments

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Regenerative Biomaterials 2024年第1期3卷 34-43页

作者： Xuanzhi Wang Tao Xu Chaoshi niu Department of Neurosurgery The First Affliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui230036China Department of Neurosurgery Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengdu 610072People's Republic of China Center for Bio-intelligent Manufacturing and Living Matter Bioprinting Research Institute of Tsinghua University in ShenzhenTsinghua UniversityShenzhen 518057People's Republicof China

Glioblastoma(GBM)is among the most common and aggressive adult central nervous system tumors.One prominent charac-teristic of GBM is the presence of abnormal microvessels.A significant correlation between angiogenesis and prognosis has been observed.Accurately reconstructing this neovascula-rization and tumor microenvironment through personalized in vitro disease models presents a significant challenge.However,it is crucial to develop new anti-angiogenic therapies for GBM.In this study,3D bioprinted glioma stem cell(GSC)-laden hydrogel scaffolds,hybrid Gsc hydrogels and ceil-free hydrogel scaffolds were manufactured to investigate the vas-cularization ability of GsCs in varying 3D microenvironments.

关键词： 3D bioprinting xenograft tumors GSC-laden hydrogel scaffold glioblastoma angiogenesis

Modeling tuberous sclerosis complex with human induced pluripotent stem cells

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World Journal of Pediatrics 2024年第3期20卷 208-218页

作者： Weibo niu Benjamin Siciliano Zhexing Wen Department of Psychiatry and Behavioral Sciences Emory University School of MedicineWhitehead Research Building 447615 Michael StreetAtlantaGA 30322USA The Graduate Program in Molecular and Systems Pharmacology Laney Graduate SchoolEmory UniversityAtlanta.GA 30322.USA Department of Cell Biology Emory University School of MedicineWhitehead Research Building 447615 Michael StreetAtlantaGA30322USA Department of Neurology Emory University School of MedicineWhitehead Research Building 447.615 Michael StreetAtlantaGA 30322USA

Background Tuberous sclerosis complex(TSC)is an autosomal dominant genetic disorder with a birth incidence of I:6000 in the United States that is characterized by the growth of non-cancerous tumors in multiple organ systems including the brain,kidneys,lungs,and skin.Importantly,TSCis also associated with signicant neurological manifestations including epilepsy TSC-associated neuropsychiatric disorders,intellectual disabilities,and autism spectrum disorder.Mutations in the TSCI or TSC2 genes are well-established causes of TSC,which lead to TSC1/TSC2 deficiency in organs and hyper-activation of the mammalian target of rapamycin signaling pathway.Animal models have been widely used to study the effect of TSCl/2 genes on the development and function of the brain.Despite considerable progress in understanding the molecular mechanisms underlying TSC in animal models,a human-specific model is urgently needed to investigate the effects of TSCl/2 mutations that are unique to human neurodevelopment.Data sources Literature reviews and research articles were published in PubMed-indexed journals.Results Human-induced pluripotent stem cells(iPSCs),which capture risk alleles that are identical to their donors and have the capacity to differentiate into virtually any cell type in the human body,pave the way for the empirical study of previously inaccessible biological systems such as the developing human brain.Conclusions In this review,we present an overview of the recent progress in modeling TSC with human iPSC models,the existing limitations,and potential directions for future research.

关键词： Induced pluripotent stem cells Three-dimensional cultures Tuberous sclerosis complex Two-dimensional cultures

An integrative mathematical model of microwave ion thruster for mHz-frequency thrust noise analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 121-136页

作者： Xiang niu Hui LIU Daren YU Plasma Propulsion Laboratory Harbin Institute of TechnologyHarbin 150001China

Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.

关键词： Electric propulsion Microwave ion thruster Integrative model Sheath property Ion beamlet divergence Thrust noise Plasma

RNA interference in insects:the link between antiviral defense and pest control

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Insect Science 2024年第1期31卷 2-12页

作者： Jinzhi niu Ruoyu Chen Jin-Jun Wang Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionSouthwest UniversityChongqingChina Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River(Ministry of Education) Southwest UniversityChongqingChina

RNA interference(RNAi)is a form of gene silencing triggered by double-stranded RNA(dsRNA)that operates in all eukaryotic cells.RNAi has been widely investigated in insects to determine the underlying molecular mechanism,to investigate its role in systemic antiviral defense,and to develop strategies for pest control.When insect cells are infected by viruses,viral dsRNA signatures trigger a local RNAi response to block viral replication and generate virus-derived DNA that confers systemic immunity.RNAi-based insect pest control involves the application of exogenous dsRNA targeting genes essential for insect development or survival,but the efficacy of this approach has limited potency in many pests through a combination of rapid dsRNA degradation,inefficient dsRNA uptake/processing,and ineffective RNAi machinery.This could be addressed by dsRNA screening and evaluation,focusing on dsRNA design and off-target management,as well as dsRNA production and delivery.This review summarizes recent progress to determine the role of RNAi in antiviral defense and as a pest control strategy in insects,addressing gaps between our fundamental understanding of the RNAi mechanism and the exploitation of RNAi-based pest control strategies.

关键词： RNAi response systemic RNAi insecticidal dsRNA biological control off-targets

Highly Thermoconductive,Strong Graphene‑Based Composite Films by Eliminating Nanosheets Wrinkles

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Nano-Micro Letters 2024年第1期16卷 328-340页

作者： Guang Xiao Hao Li Zhizhou Yu Haoting niu Yagang Yao College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional Materialsand Collaborative Innovation Center of Advanced MicrostructuresNational Laboratory of Solid State MicrostructuresNanjing UniversityNanjing 210093People’s Republic of China Institute of Laser Manufacturing Henan Academy of SciencesZhengzhou 450052People’s Republic of China Center for Quantum Transport and Thermal Energy Science School of Physics and TechnologyNanjing Normal UniversityNanjing 210023People’s Republic of China

Graphene-based thermally conductive composites have been proposed as effective thermal management materials for cooling high-power electronic devices.However,when flexible graphene nanosheets are assembled into macroscopic thermally conductive composites,capillary forces induce shrinkage of graphene nanosheets to form wrinkles during solution-based spontaneous drying,which greatly reduces the thermal conductivity of the composites.Herein,graphene nanosheets/aramid nanofiber(GNS/ANF)composite films with high thermal conductivity were prepared by in-plane stretching of GNS/ANF composite hydrogel networks with hydrogen bonds andπ-πinteractions.The in-plane mechanical stretching eliminates graphene nanosheets wrinkles by suppressing inward shrinkage due to capillary forces during drying and achieves a high in-plane orientation of graphene nanosheets,thereby creating a fast in-plane heat transfer channel.The composite films(GNS/ANF-60 wt%)with eliminated graphene nanosheets wrinkles showed a significant increase in thermal conductivity(146 W m^(−1)K^(−1))and tensile strength(207 MPa).The combination of these excellent properties enables the GNS/ANF composite films to be effectively used for cooling flexible LED chips and smartphones,showing promising applications in the thermal management of high-power electronic devices.

关键词： Graphene Aramid nanofiber Wrinkles elimination In-plane stretching Thermal conductivity

Event-triggered sliding mode control of linear repetitive processes and its application in metal rolling process

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Science China(Information Sciences) 2024年第3期67卷 167-181页

作者： Xinyu LV Yugang niu James LAM Key Laboratory of Smart Manufacturing in Energy Chemical Process (East China University of Science and Technology) Ministry of Education Department of Mechanical Engineering The University of Hong Kong

This paper investigates the design problem of a sliding mode controller for linear repetitive processes(LRPs) with a finite pass length on each pass. Under limited communication resources, an eventtriggered mechanism is implemented from the sensors to the controller, whose triggered sequence is consistent with the evolution direction of LRPs. To periodically orchestrate communication between the controller and actuator, a round-robin scheduling mechanism is established based on the pass length. A sliding function involving the state and pass profile is constructed, and the sliding mode controller is designed using triggered states and pass profile signals. Feasible controller gains are attained to ensure the stability of the resultant closed-loop system. Finally, the proposed strategy is implemented for a multi-roll metal rolling process.

关键词： event-triggered mechanism linear repetitive processes metal rolling process round-robin scheduling sliding mode control

A method for classifying whistles of bottlenose dolphin(Tursiops truncates) based on syntactic pattern reorganization

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Chinese Journal of Acoustics 2017年第3期36卷 362-372页

作者： YANG Wuyi SUN Xinzhe ZHANG Yu WEI Chong YANG Yanming niu fuqiang Key Laboratory of Underwater Acoustic Communication and Marine Information Technology(Xiamen University) Ministry of Education Third Institute of Oceanography SOA China

A method based on syntactic pattern recognition was presented to automatically classify whistles of bottlenose dolphin. Dolphin whistles have typically been characterized in terms of their instantaneous frequency as a function of time, which is also known as ＂whistle contour＂. The frequency variation features of a whistle were extracted according to its contour. Then, the frequency variation features were used for learning grammatical patterns. A whistle was classified according to grammatical pattern of its frequency variation features. The exper- imental results showed that the classification accuracy of the proposed method was 95%. The method can provide technical support for acoustic study of dolphins＇ biological behavior.

关键词： In Tursiops truncates A method for classifying whistles of bottlenose dolphin