Synthesis and Characterization of Magnetic-Luminescent Fe3O4-CdSe Core-Shell Nanocrystals

Hongling Liu,Jun-Hua Wu,민지현,Ju Hun Lee,Young Keun Kim 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.1

Nanostructures organized in unordinary spatial arrangements with multiple components such as core–shell confi gurationsendow structures, material properties and functions that diff er from the individual bulk components. In this study, we reportthe synthesis and characterization of bifunctional magnetic–luminescent Fe 3 O 4 –CdSe core–shell nanocrystals with corediameter and shell thickness of 10 and 2 nm, respectively, by controlled sequential reactions. The nanocrystals exhibit welldefined superparamagnetic behavior with high susceptibility at RT. Moreover, the fl uorescent measurements demonstrate twomajor kinds of emission peaks, one at 572 nm originating from the bandgap excitons and the other at 680 nm being surfaceassociated. These core–shell nanocrystals, coupling the optical sensing element with the magnetic actuator in a peculiarnanostructure are thereby prospected for fundamental study and various applications where multifunctionality is required.

Hydrogenation of methyl methacrylate under mild conditions using biosynthesis Ru catalyst

Hongling Zhou,Yangqiang Huang,Youwei Cheng,Lijun Wang,Xi Li 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.47 No.-

Hydrogenation of methyl methacrylate (MMA) was investigated over Ru-based catalyst supported onactive carbons (AC), which was prepared by bio-reduction method, using C. Platycladi (CP) leaf extract asreductant. By varying reaction temperature, hydrogen pressure and reaction time, hydrogenation ofMMA over the biosynthesis Ru-based catalyst was carried out, and resulted the optimum conditions,30 C (room temperature), 2.0 MPa, and 50 min. The as-prepared Ru/AC catalyst showed high catalyticactivity towards the hydrogenation of MMA, affording 100% of MMA conversion even under mildconditions without solvent and methyl isobutyrate was the only product.

Is China Ready to Recognize and Enforce Investment Arbitral Awards?

Hongling Ning,Tong Qi 이준국제법연구원 2017 China and WTO Review Vol.3 No.2

Master-followed Multiple Robots Cooperation SLAM Adapted to Search and Rescue Environment

Hongling Wang,Chengjin Zhang,Yong Song,Bao Pang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

The master-followed multiple robots interactive cooperation simultaneous localization and mapping (SLAM) schemes were designed in this paper, which adapts to search and rescue (SAR) cluttered environments. In our multi-robots SLAM, the proposed algorithm estimates each of multiple robots’ current local sub-map, in this occasion, a particle represents each of moving multi-robots, and simultaneously, also represents the pose of a motion robot. The trajectory of the robot’s movement generated a local sub-map; the sub-maps can be looked on as the particles. Each robot efficiently forms a local sub-map; the global map integrates over these local sub-maps; identifying SAR objects of interest, in which, each of multi-robots acts as local-level features collector. Once the object of interest (OOI) is detected, the location in the global map could be determined by the SLAM. The designed multi-robot SLAM architecture consists of PC remote control center, a master robot, and multi-followed robots. Through mobileRobot platform, the master robot controls multi-robots team, the multiple robots exchange information with each other, and then performs SLAM tasks; the PC remote control center can monitor multi-robot SLAM process and provide directly control for multi-robots, which guarantee robots conducting safety in harsh SAR environments. This SLAM method has significantly improved the objects identification, area coverage rate and loop-closure, and the corresponding simulations and experiments validate the significant effects.

One-pot synthesis and characterization of bifunctional Au-Fe3O4 hybrid core-shell nanoparticles

Liu, HongLing,Wu, JunHua,Min, Ji Hyun,Kim, Young Keun Elsevier 2012 JOURNAL OF ALLOYS AND COMPOUNDS Vol.537 No.-

Non-aqueous synthesis of water-dispersible Fe₃O₄–Ca₃(PO₄)₂ core–shell nanoparticles

Liu, HongLing,Wu, JunHua,Min, Ji Hyun,Hou, Peng,Song, Ah-Young,Kim, Young Keun IOP Pub 2011 Nanotechnology Vol.22 No.5

<P>The Fe<SUB>3</SUB>O<SUB>4</SUB>–Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> core–shell nanoparticles were prepared by one-pot non-aqueous nanoemulsion with the assistance of a biocompatible triblock copolymer, poly(ethylene glycol)-<I>block</I>-poly(propylene glycol)-<I>block</I>-poly(ethylene glycol) (PEO–PPO–PEO), integrating the magnetic properties of Fe<SUB>3</SUB>O<SUB>4</SUB> and the bioactive functions of Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> into single entities. The Fe<SUB>3</SUB>O<SUB>4</SUB> nanoparticles were pre-formed first by thermal reduction of Fe(acac)<SUB>3</SUB> and then the Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> layer was coated by simultaneous deposition of Ca<SUP>2 + </SUP> and PO<SUB>4</SUB><SUP>3 − </SUP>. The characterization shows that the combination of the two materials into a core–shell nanostructure retains the magnetic properties and the Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> shell forms an hcp phase (<I>a</I> = 7.490 Å, <I>c</I> = 9.534 Å) on the Fe<SUB>3</SUB>O<SUB>4</SUB> surface. The magnetic hysteresis curves of the nanoparticles were further elucidated by the Langevin equation, giving an estimation of the effective magnetic dimension of the nanoparticles and reflecting the enhanced susceptibility response as a result of the surface covering. Fourier transform infrared (FTIR) analysis provides the characteristic vibrations of Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> and the presence of the polymer surfactant on the nanoparticle surface. Moreover, the nanoparticles could be directly transferred to water and the aqueous dispersion–collection process of the nanoparticles was demonstrated for application readiness of such core–shell nanostructures in an aqueous medium. Thus, the construction of Fe<SUB>3</SUB>O<SUB>4</SUB> and Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> in the core–shell nanostructure has conspicuously led to enhanced performance and multi-functionalities, offering various possible applications of the nanoparticles.</P>

The synthesis and characterization of polymer-coated FeAu multifunctional nanoparticles

Liu, HongLing,Hou, Peng,Zhang, WengXing,Kim, Young Keun,Wu, JunHua IOP Pub 2010 Nanotechnology Vol.21 No.33

<P>We report the one-pot nanoemulsion synthesis of FeAu magnetic-optical multifunctional nanoparticles coated by the biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the resulting nanoparticles. The structural characterization identifies the crystallographic parameter 4.072 Å of the cubic phase and the morphology analysis gives the nanoparticle shape, size and size distribution, showing the high crystallinity of the FeAu nanoparticles and an average particle size of ∼ 6.5 nm. In addition there is direct confirmation of the alloying by elemental point probing of an individual nanoparticle. Following the visual demonstration of a rapid, efficient and reversible dispersion–collection process of the nanoparticles in solution, the magnetic measurement manifests a soft ferromagnetic behavior of the nanoparticles with a small coercivity of ∼ 60 Oe at room temperature. The corresponding magnetic hysteresis curves were effectively assessed by modified bi-phase Langevin equations, which were satisfactorily explained in terms of a bimodal particle size distribution. The UV–vis studies display the broadband absorption of the PEO-PPO-PEO-coated nanoparticles with the maximum surface plasmon resonance around 585 nm. The characterization and analysis, therefore, shows the unification of iron and gold into one alloy nanostructure entity covered by the biocompatible triblock copolymer thin film, preserving the optical and magnetic properties of the individual constituents. This gives the prospect of enhanced performance in applications. </P>

Combined with finite element analysis of car seat safety performance improvement

Li Hongling,Dong Yude,Chen Changliang,Chen Chao 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1

Neck injuries caused by low-speed rear-end collisions are a worldwide problem. The reasonable design of car seat can effectively prevent or reduce the passenger neck injuries. In this paper, the finite element analysis (FEA) and whiplash test are combined to optimize the seat structure parameters to enhance the safety. The whiplash test results of the existing car seats according to C-NCAP (2015) were matched with FEA, and the optimization scheme was developed by computer simulation. For the improvement of seat safety, the optimizations are applied to determine backrest stiffness, backrest rotational stiffness, headrest rotational stiffness and headrest stiffness. The retest results of optimized seat show that its safety performance is greatly improved. Furthermore, it shows that the combination of finite element analysis and whiplash test can optimize seat structure to improve safety performance.

新文化運動時期中學問題硏究及其現實意義

盧紅玲 ( Lu Hongling ) 인문사회과학예술융합학회 2019 인문사회과학예술융합학회지 Vol.3 No.2

本研究主要研究的是中国新文化运动时期中学教育的发展问题。通过研究新文化运动时期中学教育经历的“文实分科”、二部制、分科选科制等问题与争议, 探讨研究由此引发的中学教育目标、功能及课程、教学法的调整与改革。由此得知, 中学教育的改革是一项系统工程, 要受社会诸要素的影响与制约, 要与经济社会发展要求相适应, 要与人们对教育公平、接受优质教育的要求相适应。 This study mainly focus on the development of secondary education in the period of China's New Culture Movement. Through the research on the problems and controversies of " the separation of liberal arts and practical courses of study", "second department system" and " the separation and elective course system" of secondary education experienced during the New Culture Movement period, this paper mainly discusses and studies the consequent adjustment and reform of education objectives, function, curriculum and teaching methods. Therefore, the reform of secondary education is a systematic project, which would be influenced and restricted by various social factors. And it should adapt to the requirements of economic and social development, as well as meeting people's requirements of educational fairness and quality education.

한국과 중국 자동차산업 국제 경쟁력 비교 분석

정홍령 ( Ding Hongling ),이학규 ( Rhee Hack-kyu ) 한중사회과학학회 2016 한중사회과학연구 Vol.14 No.4

Auto industry has the world`s largest market. It is not only have a huge impact to steel, oil, glass, transport and other services industries. It also becomes a comprehensive industrial machinery which can produce of more than 20,000 parts belonging to dozens related industries. In this thesis firstly explaining the situation in Korea and China`s auto industry`s export and imports respectively in accordance with the types of vehicles, and then understand the status quo of their import and export between the two countries through the Korea and China`s automobile industry statistics, Lastly using the statistics between 2010 and 2014 by evaluation methods such as EMS, ESI, TSI, RCA and so on to detailed analysis the international competitiveness of Korea and China`s automobile industry respectively. Specific results of the analysis are as follows. From the export market share: Korean automobile industry in the world market share accounted for a very high level compared to the China`s and has a comparative advantage in the world market. From the export similarity index: Between Korea and China, the two countries`cars export similarity index are close to 0 so the result of the structure of exports between the two countries are not same. From the Trade Specification Index: Korean automobile industry has strong international competitiveness, but from 2010 starting persistent downward trend arisen. On the other hand China`s auto industry has weak competitiveness in the international market. From the revealed comparative advantage: Numerical of Korea`s automobile industry remained at between 1.25-2.5 with strong international competitiveness in the contrast China`s auto industry has a very weak international competitiveness by the value is lower than 0.8. In summary Korean automobile industry has a higher competitiveness and faster growth but trade specialization index showed a downward trend, while China still at a low level but is growing fast.