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Rare Metals 2009年第1期28卷 9-13页

作者： liu jinjun liu Xincai PAN Jing JIANG Chengyong State Key Laboratory Base of Novel Functional Materials and Preparation Science Faculty of Materials Science and Chemical Engineering Ningbo University Ningbo 315211 China

The C15 Laves phase with composition Tb0.2Pr0.8（Fe0.4Co0.6）1.93 was synthesized by mechanical alloying （MA） and subsequent annealing process. The structure and magnetic properties of Tb0.2Pr0.8（Fe0.4Co0.6）1.93 were investigated by means of X-ray diffraction （XRD）, a vibrating sample magnetometer, and a standard strain technique. The effect of annealing on the structure and magnetic properties was studied. The analysis of XRD shows that the high Pr-content Tb0.2Pr0.8（Fe0.4Co0.6）1.93 alloy with the single phase of MgCu2-type structure can be successfully synthesized by MA method. The sample annealed at 450℃ is found to have a coercivity of 196 kA/m at room temperature. An epoxy/Tb0.2Pr0.8（Fe0.4Co0.6）1.93 composite was produced by a cold isostatic pressing technique. A large magnetostriction of 400 ppm, at an applied magnetic field of 800 kA/m, was found for the composite. The epoxy-bonded Tb0.2Pr0.8（Fe0.4Co0.6）1.93 composite combines a high magnetostriction with a significant coercivitv, which is a oromising magnetostrictive material.

关键词： mechanical alloying magnetostriction structure magnetic properties magnetostrictive composites

Magnetic transitions and magnetocaloric effect in MnAs_(0.9)P_(0.1)

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Acta Metallurgica Sinica(English Letters) 2012年第1期25卷 76-80页

作者： Naikun SUN Feng liu Yinbo GAO jinjun liu School of Science Shenyang Ligong University Shenyang 110159 China Faculty of Materials Science & Chemical Engineering Ningbo University Ningbo 315211 China

The compound MnAs0.9P0.1 exhibits a multistep magnetic order-order transition from a helimagnetic γ-phase with Hα-type magnetic order to a ferromagnetic β-phase at 80 K and then to a helimagnetic α-phase at 203 K. The γ-β transition exhibits the characteristics of a first-order transition with a thermal hysteresis as large as 6 K, while the β-α transition is of second order with a thermal hysteresis smaller than 2 K and without magnetic hysteresis. With these two successive helimagnetism-related transitions, magnetic-entropy changes of -2.1 J/（kg·K） at 203 K for a field change from 0 to 5 T and 0.1 J/（kg·K） at 83 K for a field change from 0 to 1 T are obtained. Investigation of the magnetocaloric effect associated with a transition from Hα-type magnetic order to FM order may open a new route to explore candidates for magnetic refrigeration.

关键词： Magnetocaloric effect Hysteresis first-order transition

NEW OPTIMAL LARGE ANGLE MANEUVER STRATEGY FOR SINGLE FLEXIBLE LINK

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Chinese Journal of Mechanical Engineering 2001年第3期14卷 224-230页

作者： Shan jinjun,liu Dun (School of Astronautics, Harbin Institute of Technology) 哈尔滨工业大学航天学院黑龙江哈尔滨

A component synthesis vibration suppression (CSVS) method for flexible structures is put forward. It can eliminate any unwanted orders of flexible vibration modes while achieves desired rigid motion. This method has robustness to uncertainty of frequency, which makes it practical in engineering. Several time optimal and time-fuel optimal control strategies are designed for a kind of single flexible link. Simulation results validate the feasibility of our method.

关键词： Component synthesis vibration suppression (CSVS)method Optimal control Robustness Large angle maneuver Single flexible link

Structure and magnetostriction of high Pr/Ce-content(Tb_(0.2)Pr_(0.8))_(1-x)Ce_(x)Fe_(1.93) Laves compounds

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Journal of Rare Earths 2022年第4期40卷 670-675,I0006页

作者： Yihao Shen jinjun liu Qilin Ding Mingkun Wang Zhongbin Pan Juan Du Faculty of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China

The light rare earth Pr/Ce-contained(Tb_(0.2)Pr_(0.8))_(1–x)Ce_(x)Fe_(1.93)(0≤x≤1.0)intermetallics were arc melted and magnetoelastic properties were *** compounds of x≥0.40 are found to stabilize at ambient pressure in a single Laves phase with MgCu2-type C15 structure,which is attributed to the strong Ce 4f *** mixed-valence behavior,with a support of the deviation from the linear Vegard’s law for both lattice parameter a and saturation magnetization M_(S),is observed at room *** easy magnetization direction(EMD)was determined by the analysis of XRD on both magnetically aligned samples and the(440)splitting,that is,EMD lies towardaxis for x≤0.50 rotating tofor x=0.60,accompanied with the structural distortion from rhombohedral to *** substitution of Ce for Tb/Pr is conductive to the reduction of magnetocrystalline anisotropy,giving rise to an improvement of the low-field *** excellent magnetoelastic properties can be tailored by the Ce introduction,e.g.,the spontaneous magnetostriction coefficient λ_(111) as large as 1150×10^(−6) for x=0.40,and the low-field induced magnetostriction achieving a high value of λ_(a)=180×10^(−6) at 80 kA/m for x=*** excellent magnetoelastic properties and the combination in high Pr-content with low cost,suggest promising prospects in applications.

关键词： Light rare earth Intermetallics Laves phase X-ray diffraction Magnetic properties Magnetostriction

Phase Transformation and Magnetic Properties of Mechanically Alloyed PrCo5-based Magnets

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Journal of Materials Science & Technology 2006年第6期22卷 843-845页

作者： Xinguo ZHAO Zhidong ZHANG Qi YAO jinjun liu Weijun REN Wei liu Dianyu GENG Shenyang National Laboratory for Materials Science International Centre for Materials Physics Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

PrCo5-based nanograin Pr=CO100-x （x=14-22） alloys with high coercivity were synthesized by mechanical alloying and subsequent annealing. The crystallization, phase components and magnetic properties of the alloys were investigated systematically. The main phase of the alloy for x=14 is Pr2CO17 with rhombohedral Th2Zn17-type. The amount of the Pr2CO17 phase decreases with increasing Pr content, and a nearly single phase PrCo5 with hexagonal CaCu5-type is formed in Pr18Co81 alloy. Further increase in the Pr content leads to the formation of another magnetically hard Pr2Co7 phase with its Curie temperature about 350℃. Remanences decrease monotonously with increasing Pr content, whereas the coercivities increase, reaching a maximum of 2040 kA/m （25.6 kOe） in Pr19CO81 powders milled for 5 h and annealed at 973 K for 2 min, and then decrease for higher Pr content. The high coercivity is attributed to the high anisotropy field of the PrCo~ phase and its nanoscale grain size.

关键词： Pr-Co magnets Phase transformation Magnetic properties Mechanical alloying

Structure and magnetostriction of Tb_(0.4)Nd_(0.6)(Fe_(0.8)Co_(0.2))_(1.90) alloy prepared by solid-state synthesis

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Rare Metals 2012年第6期31卷 547-551页

作者： liu jinjun Wang Rong Yin Hongyun liu Xincai Si Pingzhan Du Juan Ningbo Univ State Key Lab Base Novel Funct Mat & Preparat Sci Fac Mat Sci & Chem Engn Ningbo 315211 Zhejiang Peoples R China China Jiliang Univ Coll Mat Sci & Engn Hangzhou 310018 Zhejiang Peoples R China Chinese Acad Sci Ningbo Inst Mat Technol & Engn Ningbo 315201 Zhejiang Peoples R China

Mechanical alloying (MA) and subsequent solid sintering process was used to prepare the Nd-containing magnetostrictive Tb0.4Nd0.6(Fe0.8Co0.2)1.90 alloy. The structure, thermal stability and phase transformation were investigated as functions of composition, milling process and annealing temperature. An amorphous phase was formed by high-energy ball milling for 5 h with the ball-to-powder weight ratio of 20:1, which crystallized into MgCu2-type and PuNi3-type crystalline structure with different annealing temperatures. The magnetoelastic properties were investigated by means of a standard strain technique. The high Nd-content (Tb,Nd)(Fe,Co)2 Laves phase for the composition Tb0.4Nd0.6(Fe0.8Co0.2)1.90 was synthesized by MA process plus annealing at 500 ℃ for 30 min.

关键词： mechanical alloying magnetostriction structure light rare earth

Polypyrrole random-coil induced permittivity from negative to positive in all-organic composite films

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Journal of Materiomics 2020年第2期6卷 348-354页

作者： Peng Wang Zhongbin Pan Mingkun Wang Shuangwu Huang jinjun liu Jiwei Zhai School of Materials Science and Chemical Engineering Ningbo UniversityNingboZhejiang315211China School of Materials Science&Engineering Tongji University4800 Caoan RoadShanghai201804China

Percolating composites with negative permittivity can be promising candidates for ***,novel all-organic composite films containing of random coil polypyrrole(PPy)and poly(-vinylidene fluoride)(PVDF)are fabricated via a solution casting *** random coil PPy is prepared by oxidative template assembly approach for the first *** experimental result indicates that the negative permittivity is easily adjusted through controlling the random coil PPy ***,the random coil PPy contents exceeded 7 wt% the negative permittivity appear attributed to the formation of 3D interconnected PPy *** facile approach not only opens a new way to preparing negative permittivity of all-organic composite films,but also points out a route to facilitate the practical applications of metamaterials.

关键词： Polypyrrole Composite films Random coil Negative permittivity

Improved extraction efficiency of bakuchiol with antioxidant and whitening bioactivities from the seeds of Psoralea corylifolia L.

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Science of Traditional Chinese Medicine 2023年第2期1卷 123-128页

作者： Tian Qin jinjun liu Yongxian Bi Yanduo Wang Jianzi liu Gang Ding Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine Ministry of EducationInstitute ofMedicinal Plant DevelopmentChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Zhejiang Yige Enterprise Management Group Co LtdHangzhouChina

Background:Mining new whitening ingredients from plants is an effective way to develop new cosmetic ***,as one of the main active ingredients from the seeds of Psoralea corylifolia L,displays whitening,antioxidant,antiaging,and free radical-scavenging activities and attracts wide attention especially in the cosmetics ***,environmentally friendly extraction technologies with high efficiency and high product purity remain to be developed for the scale production of ***:In this study,a new approach(acetic acid–steaming–assisted technique)was developed to improve the extraction efficiency of ***:The factors influencing the extraction efficiency of bakuchiol,including seed powder granularity,acetic acid volume,temperature,and time,were optimized based on single-factor ***:The extraction conditions were optimized as steaming the seed powder(100 g)of 40–100meshes with acetic acid(50 mL)for 10 minutes,from which a crude extract(25.1 g)containing bakuchiol was *** purity(99.1)of bakuchiol(6.02 g)was then prepared by silica gel column chromatography in a one-step *** method established in this study had higher extraction rate than other *** antioxidant potential of bakuchiol was evaluated based on the ABTS free radical scavenging activity and ferric reducing antioxidant ***,bakuchiol demonstrated stronger tyrosinase inhibitory activity than the positive control(arbutin).Conclusions:Compared with the available methods,the method established in this study has increased extraction rate of bakuchiol and is environmentally friendly and economical,demonstrating the potential for industrial production.

关键词： Seeds of Psoralea corylifolia L. Bakuchiol Acetic acid-steaming Separation Structural elucidation Antioxidant and tyrosinase inhibitory activities

Excellent thermal stability and high energy storage performances of BNT-based ceramics via phase-structure engineering

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Journal of Materiomics 2023年第6期9卷 1015-1023页

作者： Mingkun Wang Tian Bai Aina He Zhongbin Pan Jinghao Zhao Luomeng Tang Zhihe Zhao jinjun liu Shushuang Li Weixing Xia Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo315201China University of Chinese Academy of Science Beijing100049China School of Materials Science and Chemical Engineering Ningbo UniversityNingbo315211China Ningbo Productivity Promotion Center Ningbo315040China

Herein,a novel strategy for regulating the phase structure was used to significantly enhance the recoverable energy storage density(Wrec)and the thermal stability via designing the(1-x)[(Bi_(0.5)Na_(0.5))_(0.7)Sr_(0.3)TiO_(3)]-xBiScO_(3)((1-x)BNST-xBS)relaxor ferroelectric *** incorporation of BS into BNST ceramics markedly increases the local micro-structure disorder,causing a high polarization and inhibiting polarization hysteresis for 0.95BNST-0.05BS ceramics,leading to a large Wrec of 5.41 J/cm^(3)with an ideal efficiency(h)of 78.5%.Meanwhile,transmission electron microscope(TEM)results further proved that the nano-domain structure and the tetragonal(P4bm)phase superlattice structure of 0.95BNST-0.05BS ceramics possess an excellent thermal stability(20-200℃).An outstanding Wrec value of 3.18×(1.00±0.03)J/cm^(3)and an h value of 74.500±0.025 are achieved under a temperature range from 20℃to 200℃.This work provides a promising method for phase-structure design that can make it possible to apply temperature-insensitive ceramic dielectrics with a high energy storage density in harsh environments.

关键词： Relaxor ferroelectric Energy storage properties Thermal stability Nano-domain

Enhanced energy-storage performance in BNT-based lead-free dielectric ceramics via introducing SrTi_(0.875)Nb_(0.1)O_(3)

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Journal of Materiomics 2022年第3期8卷 537-544页

作者： Lukang Wu Luomen Tang Yizan Zhai Yiling Zhang Jianjian Sun Di Hu Zhongbin Pan Zhen Su Yang Zhang jinjun liu School of Materials Science and Chemical Engineering Ningbo UniversityZhejiangNingbo315211China China-Australia Institute for Advanced Materials and Manufacturing Jiaxing UniversityJiaxingZhejiang34001China School of Chemical and Materials Engineering Chaohu UniversityHefei238000China

Environmentally friendly lead-free ceramics capacitors,with outstanding power density,rapid charging/discharging rate,and superior stability,have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low-consumption ***,the relatively low energy storage capability must be urgently ***,this work reports on leadfree SrTi_(0.875)Nb_(0.1)O_(3)(STN)replacement of(Bi_(0.47)La_(0.03)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)(BLNBT)ferroelectric ceramics with excellent energy storage *** relaxor behaviour and breakdown strength(Eb),decreasing grain size,and mitigating large polarization difference are conductive to the enhancement of comprehensive energy storage *** phase-field simulation methods are further analysized evolution process of electrical tree in the experimental *** particular,the 0.70BLNBT-0.30STN ceramic exhibit a large discharged energy density of 4.2 J/cm^(3) with an efficiency of 89.3%at room temperature under electric field of 380 kV/***,for practical applications,the BLNBT-based ceramics achieve a high power density(~62.3 MW/cm^(3))and fast discharged time(~148.8 ns)over broad temperature range(20-200℃).Therefore,this work can provide a simple and effective guideline paradigm for acquiring high-performance dielectric materials in low-consumption systems operating in a wide range of temperatures and long-term operations.

关键词： Lead-free ceramics Energy storage properties Relaxor behaviour Thermal stability Charge-discharge performance