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Integrated fabrication process with multiple optimized factors for high power density of IPMC actuator

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International Journal of Smart and Nano Materials 2022年第4期13卷 643-667页

作者： Zicai zhu Changsheng Bian Wanfa bai Qiao Hu Suijun chen Shaanxi Key Laboratory of Intelligent Robots School of Mechanical EngineeringXi’an Jiaotong UniversityXi’anChina Research and Development Center Xi’an Aerospace Automation Co.LtdXi’anChina Xi’an ABLE Smart Actuation Material Technology Ltd Xi’anChina

Ionic polymer-metal composites(IPMCs)are typical smart mate-rials that are commonly used in bionic applications,including soft robots,bionic flapping aircraft,and bionic fish.However,their low output force seriously limits device performance.Stacking of multiple IPMC actuators to improve the overall performance of soft actuators is a strategy that is used in practical applications.Under the energy dissipation condition in the IPMC stacking structure,if each single IPMC in the struc-ture has high power density,the structure will produce excel-lent performance with high efficiency that can greatly promote wider application of IPMC actuators.To meet this requirement,a method for fabrication process integration with multiple opti-mized factors was used to obtain IPMC materials in this paper.Carbon nanotube(CNT)doping,isopropyl alcohol-assisted plat-ing,and hot pressing with a mesoscopic structural mold were selected as typical optimization methods for process integration and were initially investigated separately to determine the opti-mal process parameters.By combining the best process para-meters in an integrated process,the IPMC treated by isopropyl alcohol-assisted plating and CNT doping process(No.AC7)showed excellent actuation performance and high work density(~9.71/12.36 gf,~14.93/31.89 kJ/m^(3) under 3/4 VDC).The enhanced performance meets the requirements for practical bionic applications.

关键词： Ionic polymer-metal composite IPMC blocking force fabrication process work density

Food economics and policies: Challenges and approaches toward better nutrition and safer food in China

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Journal of Integrative Agriculture 2019年第8期18卷 1737-1739页

作者： bai Jun-fei zhu chen Beijing Food Safety Policy & Strategy Research Base China Agricultural University

China has achieved unprecedented successes in feeding the 1.3 billion population in the past few decades. Per capita occupation of grain and milk increased from 316.6 and 1 kg in 1978 to 445.7 and 26.85 kg in 2016, respectively. Per capita meat occupation also reached 61.9 kg in 2016 from nearly nothing at the beginning of the reform and opening (NBSC 1979-2018). With these successes in agricultural production, the quality of food consum ption has also improved significantly.

关键词： Food economics Challenges and approaches safer food

Numerical simulation of coupling multi-physical field in electrical arc furnace for smelting titanium slag

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Journal of Iron and Steel Research(International) 2023年第11期30卷 2194-2209页

作者： He-nan Cui Tao Li chen-guang bai Min Tan Yu-lin zhu College of Materials Science and Engineering Chongqing UniversityChongqing400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing400044China College of Metallurgy and Energy North China University of Science and TechnologyTangshan063210HebeiChina

The smelting reduction process of the ilmenite in an electric arc furnace(EAF)is a commonly used technology for producing titanium slag in the world.It has particular significance to analyze the velocity-temperature-electromagnetics multi-physical field in an EAF for improving its productivity and reducing energy consumption.A transient three-dimensional mathematical model was developed to characterize the flow,heat transfer,and electromagnetic behavior in a titanium slag EAF.For describing the electromagnetic field and its effects on velocity and temperature distribution in the furnace,magnetohydrodynamic equations and conservation equations for mass,momentum,and energy were solved simultaneously by compiling the user-defined function program.The numerical model was verified by comparing with the literature data.The results indicate that the Lorentz force is the main driving force of the velocity and temperature distribution.Moreover,the influence of input current and location of electrodes on the multi-physical field distribution was also investigated.It is found that the appropriate range of input current and diameter of pitch circle are about 30,000 A and 3000-3500 mm,respectively.The mathematical model established can characterize the multi-physical field more accu-rately than before,which can provide valuable guidance for the operation improvement and design optimization of the EAF for producing titanium slag.

关键词： Electric arc furnace Titanium slag Magnetohydrodynamic Multi-physical field User-defined function

Design and Experiments of a Human-Leg-Inspired Omnidirectional Robotic Leg

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Journal of Bionic Engineering 2023年第6期20卷 2570-2589页

作者： Yuze Xu Zirong Luo Xiangjuan bai Huixiang Xie Yiming zhu Shanjun chen Jianzhong Shang College of Intelligence Science and Technology National University of Defense TechnologyChangsha410073China PLA Rocket Force University of Engineering Xi’an710025China

Bionic-based robotic legs enable the legged robots with elegant and agile mobility in multi-terrain environment,just like natural living beings.And the smart design could efficiently improve the performance of a robotic leg.Inspired by the simplified human leg structure,we present a 3-DOF robotic leg—OmniLeg,that is capable of making omnidirectional legged locomotion while keeping constant posture of the foot.Additionally,the concentrated drive mode,in which all the motor actuators are installed in the torso and do not move with the leg,minimizes the inertia of the robotic leg.In this paper,the modular design,the kinematics model,the structural analysis,the workspace,and the performance evaluation of the OmniLeg are discussed.Furthermore,we build a prototype based on the proposed design,and the precision of it is verified by the error calibration experiment which is conducted by tracking the trajectory of the prototype’s endpoint.Then,we present an OmniLeg-based single legged mobile robot.The capability of omnidirectional legged locomotion of the OmniLeg is demonstrated by the experiments.

关键词： Human leg Robotic leg Omnidirectional legged locomotion Spatial dual-parallelogram-linkages Spatial closed-loop four-bar

Visualization of Bulk Polymerization by Fluorescent Probe with Aggregation-induced Emission Characteristics

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Chemical Research in Chinese Universities 2022年第2期38卷 500-504页

作者： NIU Junfeng SUN Haiya XIA Housheng zhu Yinbang chen Jialing zhu chengye bai Wei School of Biological and Chemical Engineering Zhejiang University of Science&TechnologyHangzhou 310023P.R.China MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027P.R.China

Bulk polymerization is one of the most commonly used techniques in polymer preparing due to its relatively simple process,low cost and easier aftertreatment of the product[1-5].Bulk polymerization has attracted much attention in both academic researches and industrial productions of commodity polymers,such as poly(methyl methacrylate)(PMMA)[6]and polystyrene(PS)[7].During the process of bulk polymerization,an autoacceleration phenomenon,which is also referred to as the gel or Trommsdorff effect,is often observed[8].

关键词： Aggregation-induced emission Bulk polymerization Fluorescence probe

Machine learning based altitude-dependent empirical LoS probability model for air-to-ground communications

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Frontiers of Information Technology & Electronic Engineering 2022年第9期23卷 1378-1389页

作者： Minghui PANG Qiuming zhu Zhipeng LIN Fei bai Yue TIAN zhuo LI Xiaomin chen Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space College of Electronic and Information EngineeringNanjing University of Aeronautics and AstronauticsNanjing211106China State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an710000China Key Laboratory of Radar Imaging and Microwave Photonics Ministry of EducationCollege of Electronic and Information EngineeringNanjing University of Aeronautics and AstronauticsNanjing211106China

Line-of-sight(LoS)probability prediction is critical to the performance optimization of wireless communication systems.However,it is challenging to predict the LoS probability of air-to-ground(A2G)communication scenarios,because the altitude of unmanned aerial vehicles(UAVs)or other aircraft varies from dozens of meters to several kilometers.This paper presents an altitude-dependent empirical LoS probability model for A2G scenarios.Before estimating the model parameters,we design a K-nearest neighbor(KNN)based strategy to classify LoS and non-LoS(NLoS)paths.Then,a two-layer back propagation neural network(BPNN)based parameter estimation method is developed to build the relationship between every model parameter and the UAV altitude.Simulation results show that the results obtained using our proposed model has good consistency with the ray tracing(RT)data,the measurement data,and the results obtained using the standard models.Our model can also provide wider applicable altitudes than other LoS probability models,and thus can be applied to different altitudes under various A2G scenarios.

关键词： Line-of-sight probability model Air-to-ground channel Machine learning Ray tracing

Grenvillian and early Paleozoic polyphase metamorphism recorded by eclogite and host garnet mica schist in the North Qaidam orogenic belt

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Geoscience Frontiers 2021年第4期12卷 244-259页

作者： Yunfei Ren Danling chen Haijie Wang Xiaohui zhu Bowen bai State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi'an 710069China Xi'an Center of Geological Survey China Geological SurveyXi'an 710054China

The North Qaidam orogenic belt(NQOB) is generally considered to be an early Paleozoic ultrahigh pressure metamorphic belt,but increasing reports of the Neoproterozoic magmatic and metamorphic events indicate that the NQOB probably also experienced the assembly of the Rodinia.However,the Neoproterozoic evolution of the NQOB is not well constrained due to the sparse records and ambiguous nature of the Neoproterozoic metamorphism.In order to reveal the multi-orogenic history of the NQOB,an integrated study of petrology,phase equilibrium modelling and geochronology was conducted on an epidote eclogite and host garnet mica schist from the Yuka–Luofengpo terrane.New zircon and monazite U–Pb ages show that the protolith of the garnet mica schist was deposited during 994–920 Ma and experienced Neoproterozoic(920–915 Ma) and early Paleozoic(451–447 Ma) polyphase metamorphism together with the enclosed eclogite.Relic omphacite inclusions were first identified in garnet and early Paleozoic zircon domains from the garnet mica schist,which provide solid evidence for the early Paleozoic eclogite facies metamorphism of the mica schist.Similar early Paleozoic peak P–T conditions of >27.4 kbar/613–670 ℃ and 30.2–30.8 kbar/646–655 ℃ were obtained for the garnet mica schist and enclosed eclogite,respectively,indicating that eclogites and their host paragneisses in this region underwent continental deep subduction as a coherent metamorphic terrane in early Paleozoic.The peak P–T conditions of the Neoproterozoic metamorphism were roughly constrained at 7.7–12.0 kbar and 634–680 ℃ for the garnet mica schist,based on stability field of mineral inclusions in Neoproterozoic zircons domains in P–T pseudosection,the relic garnet core composition and Ti-in-zircon thermometer.The high thermal gradients(16–37 ℃/km) defined by presently our and previously reported P–T conditions indicate that the Neoproterozoic metamorphism likely occurred in continental collision setting at >945–890 Ma.Since the Grenvillian syn-orogenic granitic magmatism and

关键词： Grenvillian metamorphism Two orogenic cycles Pseudosection North Qaidam Rodinia

Multiple olfactory pathways contribute to the lure process of Caenorhabditis elegans by pathogenic bacteria

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Science China(Life Sciences) 2021年第8期64卷 1346-1354页

作者： Man zhu Yao chen Ninghui Zhao Hua bai Keqin Zhang Xiaowei Huang State Key Lab for Conservation and Utilization of Bio-Resources and College of Life ScienceYunnan UniversityKunming 650091China Neurosurgery of the Second Hospital Affiliated with Kunming Medical University Kunming 650101China College of Public Health Kunming Medical UniversityKunming 650500China

Chemosensation is indispensable for the survival of Caenorhabditis elegans to discriminate food and pathogenic bacteria in their living environment. Food-like odors emitted by the pathogen Bacillus nematocida B16 for trapping its hosts and an olfactory signaling pathway responsible to sense the attractant 2-heptanone were identified in our previous study. Here, we further explore how the worms recognize the attractive molecules indole and 2-ethyl hexanol, which have different chemical properties and modest nematode-luring ability. We show that the chemotaxis toward indole and 2-ethyl hexanol requires the G protein-coupled receptors encoded by str-193 on AWC and str-7 on AWA. In a further genetic screen for downstream effectors in olfactory signaling cascades, the Gα subunit GSA-1, guanylyl cyclase ODR-1 and DAF-11 and the c GMP-gated channel TAX-2/TAX-4 were found to be necessary for indole sensation, whereas the TRPV channels OSM-9/OCR-2 and the PLC pathway activated by GPA-6 are responsible for the detection of 2-ethyl hexanol. Altogether, our current work further clarifies the distinct olfactory signaling pathways through which C. elegans senses different chemicals and is lured by B. nematocida B16, improving our comprehensive understanding of the mechanisms by which bacterial pathogens effectively infect their hosts.

关键词： attractive trapping process

PREPARATION OF SINGLE-HOLE HOLLOW POLYMER NANOSPHERES BY RASPBERRY-LIKE TEMPLATE METHOD

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Chinese Journal of Polymer Science 2013年第2期31卷 294-301页

作者： Yong Zhang Jia-jia chen Geng-hui Zhang Bai-zhu Chen 阎虎生 Key laboratory of Functional Polymer Materials (Ministry of Education) Institute of Polymer Chemistry Nankai University

Single-hole hollow polymer nanospheres were fabricated by raspberry-like template method using ＂graft-from＂ strategy through atom transfer radical polymerization （ATRP）. Nanometer-sized silica spheres were covalently attached onto the surfaces of micrometer-sized silica spheres. Crosslinked polymer shells on the nano-sized spheres outside the attached area were formed by ＂graft-from＂ strategy through ATRP. After removal of the silica cores, single-hole hollow crosslinked polymer nanospheres were obtained. In this strategy, most of ATRP monomers may be used and thus many functional groups can be easily incorporated into the single-hole hollow crosslinked polymer nanospheres.

关键词： Single-hole Hollow polymeric nanoparticles ATRP.