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Synthesis of a Rod-rod Diblock Copolymer, Poly (3-hexylthiophene)-block-poly(furfuryl isocyanate), through the Anionic Polymerization with an Oxyanionic Macroinitiator

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Chinese Journal of Polymer Science 2019年第9期37卷 866-874页

作者： chang-geun Chae Joonkeun Min In-Gyu Bak Jae-Suk lee School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST)

A rod-rod diblock copolymer (diBCP), poly(3-hexylthiophene)-block-poly(furfuryl isocyanate)(P3HT-b-PFIC), was synthesized through the anionic polymerization with an oxyanionic macroinitiator of P3HT. The properties of the diBCP (molecular weight, dispersity, composition, thermal stability, UV-visible absorption, and thin film morphology) were determined by various analytical methods. P3HT-b-PFIC was blended with C60 in a toluene solution to prepare a thin film of binary electron donor/acceptor system. Such blending enabled partial conjugation of the two components by the Diels-Alder reaction between furan and C60 at 60℃ for 3 h;the mixture was then spin-cast as a thin film, and annealed at 250℃ for 24 h. Tapping-mode atomic force microscopy (AFM) revealed that P3HT and C60 domains had nanoscale interfaces without a large phase segregation. This result indicated that the microphase separation of C60-functionalized P3HT-b-PFIC preserved even at high temperature provided free C60 molecules with channels to diffuse on the sides of P3HT domain, thus preventing the macroscopic crystallization of free C60 through the interfacial stabilization.

关键词： Rod-rod diblock copolymer Poly(3-hexylthiophene)-block-poly(furfuryl isocyanate) C60 Diels-Alder reaction Nanoscale interfaces

Distribution of electric field for carbon nanotube assembly: Simulation (I)

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 117-120页

作者： Soon-geun KWON Soo-Hyun KIM Kwang-Ho KIM Myung-chang KANG Hyung-Woo lee Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

The distribution of electric field for the alignment and attachment of carbon nanotubes (CNTs) was simulated. To be attached at the desired place, the aligned and attracted CNTs should be stayed in the desired area called the stable region or the quasi-stable region for an instant where the change of electric field is minimized. Since the conical electrode has the very narrow sized quasi-stable region, few CNTs can be attached. The rectangular electrodes have a wide stable region, so lots of CNTs can be attached. The results indicate that the round electrode which has a proper sized quasi-stable region is more effective for aligning and attaching a single CNT than the conical or rectangular shaped electrodes.

关键词： carbon nanotubes (CNTs) dielectrophoresis (DEP) round shaped electrode simulation

Microfluidic dual loops reactor for conducting a multistep reaction

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Frontiers of Chemical Science and Engineering 2018年第2期12卷 239-246页

作者： Si Hyung Jin Jae-Hoon Jung Seong-geun Jeong Jongmin Kim Tae Jung Park chang-Soo lee Department of Chemical Engineering Chungnam National University Daejeon 34134 Korea Lotte Chemical R&D Center Daejeon 34110 Korea Department of Chemistry Chung-Ang University Seoul 06974 Korea

Precise control of each individual reaction that constitutes a multistep reaction must be performed to obtain the desired reaction product efficiently. In this work, we present a microfluidic dual loops reactor that enables multistep reaction by integrating two identical loop reactors. Specifically, reactants A and B are synthesized in the first loop reactor and transferred to the second loop reactor to synthesize with reactant C to form the final product. These individual reactions have nano-liter volumes and are carded out in a stepwise manner in each reactor without any cross-contamination issue. To pre- cisely control the mixing efficiency in each loop reactor, we investigate the operating pressure and the operating frequency on the mixing valves for rotary mixing. This microfluidic dual loops reactor is integrated with several valves to realize the fully automated unit operation of a multistep reaction, such as metering the reactants, rotary mixing, transportation, and collecting the product. For proof of concept, CdSeZn nanopartieles are successfully synthesized in a microfluidic dual loops reactor through a fully automated mukistep reaction. Taking all of these features together, this microfluidic dual loops reactor is a general microfluidic screening platform that can synthesize various materials through a multistep reaction.

关键词： microfluidics multistep reaction rotary mixing nanoparticle

Accurate Multi-Scale Feature Fusion CNN for Time Series Classification in Smart Factory

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Computers, Materials & Continua 2020年第10期65卷 543-561页

作者： Xiaorui Shao chang Soo Kim Dae geun Kim Department of Information Systems Pukyong National UniversityBusan608737South Korea Korea Dyeing&Finishing Technology Institute Busan608737South Korea

Time series classification(TSC)has attracted various attention in the community of machine learning and data mining and has many successful applications such as fault detection and product identification in the process of building a smart ***,it is still challenging for the efficiency and accuracy of classification due to complexity,multi-dimension of time *** paper presents a new approach for time series classification based on convolutional neural networks(CNN).The proposed method contains three parts:short-time gap feature extraction,multi-scale local feature learning,and global feature *** the process of short-time gap feature extraction,large kernel filters are employed to extract the features within the short-time gap from the raw time ***,a multi-scale feature extraction technique is applied in the process of multi-scale local feature learning to obtain detailed *** global convolution operation with giant stride is to obtain a robust and global feature *** comprehension features used for classifying are a fusion of short time gap feature representations,local multi-scale feature representations,and global feature *** test the efficiency of the proposed method named multi-scale feature fusion convolutional neural networks(MSFFCNN),we designed,trained MSFFCNN on some public sensors,device,and simulated control time series data *** comparative studies indicate our proposed MSFFCNN outperforms other alternatives,and we also provided a detailed analysis of the proposed MSFFCNN.

关键词： Time Series Classifications(TSC) smart factory Convolutional Neural Networks(CNN)

Thermal performance analysis of borehole size effect on geothermal heat exchanger

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Journal of Central South University 2012年第12期19卷 3524-3529页

作者： CHOI Hoon-ki YOO geun-jong LIM Kyung-bin lee Sang-hoon lee chang-hee Department of Mechanical Design and Manufacturing Engineering Changwon National UniversityChangwon 641-773Korea Department of Mechanical Design Engineering Hanbat National UniversityDaejon 305-719Korea Department of Energy Engineering Jeonju UniversityJeonju 560-759Korea STX Institute of Technology Changwon 642-845Korea

Thermal performance was the most important factor in the development of borehole heat exchanger utilizing geothermal energy. The thermal performance was affected by many different design parameters, such as configuration type and borehole size of geothermal heat exchanger. These eventually determined the operation and cost efficiency of the geothermal heat exchanger system. The main purpose of this work was to assess the thermal performance of geother^nal heat exchanger with variation of borehole sizes and numbers of U-tubes inside a borehole. For this, a thermal response test rig was established with line-source theory. The thermal response test was performed with in-line variable input heat source. Effective thermal conductivity and thermal resistance were obtained from the measured data. From the measurement, the effective thermal conductivity is found to have similar values for two- pair type （4 U-tubes） and three-pair type （6 U-tubes） borehole heat exchanger systems indicating similar heat transfer ability. Meanwhile, the thermal resistance shows lower value for the three-pair type compared to the two-pair type. Measured data based resistance have lower value compared to computed result from design programs. Overall comparison finds better thermal performance for the three-pair type, however, fluctuating temperature variation indicates complex flow behavior inside the borehole and requires further study on flow characteristics.

关键词： large size borehole heat exchanger thermal response test effective thermal conductivity thermal resistance borehole

Characteristic analysis of bleeding effect on standing column well (SCW) type geothermal heat exchanger

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Journal of Central South University 2012年第11期19卷 3202-3207页

作者： CHOI Hoon-ki YOO geun-jong LIM Kyung-bin lee Sang-hoon lee chang-hee Department of Mechanical Design/Manufacturing Engineering Changwon National UniversityChangwon 641-773Korea Department of Mechanical Design Engineering Hanbat National UniversityDaejon 305-719Korea Department of Energy Engineering Jeonju UniversityJeonju 560-759Korea STX Institute of Technology Gyeongnam 642-845Korea

Thermal performance is the most important factor in the development of a borehole heat exchanger utilizing geothermal *** thermal performance is affected by many different design parameters and different operating conditions such as *** eventually determines the operation and cost efficiency of the borehole heat exchanger *** thermal performance of an open standing column well (SCW) type geothermal heat exchanger was assessed under the influence of *** this,a thermal response test rig was established with line-source *** test rig also had a bleeding function by releasing fluid while taking additional underground water through the heat *** thermal response test was performed with an additional constant input heat *** thermal conductivity and thermal resistance were obtained from the measured *** the measurement,the effective thermal conductivity is found to have 1.47 times higher value when bleeding is *** thermal resistance also increases by 1.58 times compared to a non-bleeding *** trend indicates enhanced heat transfer in the SCW type heat exchanger with a bleeding ***,therefore,could be an effective method of achieving a high heat transfer rate in the SCW type heat exchanger with sufficient underground water supply.

关键词： standing column well type thermal response test effective thermal conductivity thermal resistance bleeding effect

Femoral neck stress fractures after trampoline exercise:A case report

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World Journal of Clinical Cases 2021年第18期9卷 4783-4788页

作者： Dae Cheol Nam Sun Chul Hwang Eun chang lee Myung-geun Song Jun-Il Yoo Department of Orthopaedic Surgery Gyeongsang National University School of MedicineJinju 52727South Korea Department of Orthopaedic Surgery and Institute of Health Sciences Gyeongsang National University School of Medicine and Gyeongsang National University HospitalJinju 52727South Korea

BACKGROUND Femoral neck stress fractures(FNSFs)are commonly found in long-distance running *** FNSFs,early diagnosis and proper treatment are *** objective of this study was to report FNSFs that occurred after excessive exercise using trampoline in middle-aged *** SUMMARY The patient was a 43-year-old woman who exercised jumping on a trampoline for 6 wk for 1-3 h a day to *** includes repeated flexion-extension of the hip *** patient was admitted to the hospital due to sudden bilateral groin pain that occurred suddenly during a trampoline *** magnetic resonance imaging(MRI)revealed bilateral *** 2 wk of follow-up with conservative treatment,the pain slightly ***,it did not disappear *** was determined that it was difficult to control symptoms only by conservation ***,closed reduction and internal fixation using a cannulated screw were performed for the more painful left hip *** operation,the pain was *** using crutches was *** MRI showed that the right femoral head signal was decreased compared to the left femoral head ***,nonsteroidal anti-inflammatory drug and conservative treatment were *** In middle-aged people,excessive trampoline exercise can repeat hip flexion and extension for a short period of time,leading to FNSFs.

关键词： Trampoline exercise Femoral neck stress fracture Neck Fracture Case report

Cytochrome b5 Reductase 1 Triggers Serial Reactions that Lead to Iron Uptake in Plants

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Molecular Plant 2016年第4期9卷 501-513页

作者： Young Jun Oh Hanul Kim Sung Hee Seo Bae geun Hwang Yoon Seok chang Junho lee Dong Wook lee Eun Ju Sohn Sang Joon lee Youngsook lee Inhwan Hwang Division of Integrative Biosciences and Biotechnology Department Life Sciences Division of Environmental Science and Engineering Division of Mechanical Engineering Pohang University of Science and Technology Pohang 790-784 Korea

Rhizosphere acidification is essential for iron （Fe） uptake into plant roots. Plasma membrane （PM） H＊-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H＋-ATPase activity is regulated to enhance root Fe uptake under Fe-deficient conditions. Here, we present evidence that cytochrome b5 reductase 1 （CBR1） increases the levels of unsaturated fatty acids, which stimulate PM H＋-ATPase activity and thus lead to rhizosphere acidification. CBRl-overexpressing （CBRI-OX） Arabidopsis thaliana plants had higher levels of unsaturated fatty acids （18：2 and 18：3）, higher PM H＊-ATPase activity, and lower rhizosphere pH than wild-type plants. By contrast, cbrl loss-of-function mutant plants showed lower levels of unsaturated fatty acids and lower PM H＊-ATPase activity but higher rhizosphere pH. Reduced PM H＊-ATPase activity in cbrl could be restored in vitro by addition of unsatu- rated fatty acids. Transcript levels of CBR1, fatty acids desaturase 2 （FAD2）, and fatty acids desaturase 3 （FAD3） were increased under Fe-deficient conditions. We propose that CBR1 has a crucial role in increasing the levels of unsaturated fatty acids, which activate the PM H＊-ATPase and thus reduce rhizosphere pH. This reaction cascade ultimately promotes root Fe uptake.

关键词： cytochrome b5 reductase 1 (CBR1) unsaturated fatty acids iron (Fe) uptake H^+-ATPase

Dopant-Tunable Ultrathin Transparent Conductive Oxides for Efficient Energy Conversion Devices

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Nano-Micro Letters 2021年第12期13卷 437-451页

作者： Dae Yun Kang Bo-Hyun Kim Tae Ho lee Jae Won Shim Sungmin Kim Ha-Jun Sung Kee Joo chang Tae geun Kim School of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea Department of Advanced Materials Engineering Kongju National UniversityCheonan 31080Republic of Korea Department of Physics Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea

Ultrathin film-based transparent conductive oxides(TCOs)with a broad work function(WF)tunability are highly demanded for e cient energy conversion ***,reducing the film thickness below 50 nm is limited due to rapidly increasing resistance;furthermore,introducing dopants into TCOs such as indium tin oxide(ITO)to reduce the resistance decreases the transparency due to a trade-o between the two ***,we demonstrate dopant-tunable ultrathin(≤50 nm)TCOs fabricated via electric field-driven metal implantation(m-TCOs;m=Ni,Ag,and Cu)without com-promising their innate electrical and optical *** m-TCOs exhibit a broad WF variation(0.97 eV),high transmittance in the UV to visible range(89–93%at 365 nm),and low sheet resistance(30–60Ωcm-2).Experimental and theoretical analyses show that interstitial metal atoms mainly a ect the change in the WF without substantial losses in optical *** m-ITOs are employed as anode or cathode electrodes for organic light-emitting diodes(LEDs),inorganic UV LEDs,and organic photovoltaics for their universal use,leading to outstanding performances,even without hole injection layer for OLED through the WF-tailored *** results verify the proposed m-TCOs enable e ective carrier transport and light extraction beyond the limits of traditional TCOs.

关键词： Transparent conductive oxide Metal implantation High transparency Low sheet resistance Work function