연구보문 : 자연과학 ; 황산처리에 의한 불투수성 황근 종자의 발아촉진에 관한 연구

서상흠 ( Sang Heum Seo ),박민우 ( Min Woo Park ),장미하 ( Mi Ha Chang ),장일웅 ( Il Ung Jang ),심상인 ( Sang In Shim ),나영왕 ( Young Wang Na ),김수영 ( Soo Young Kim ),김석현 ( Seok Hyeon Kim ) 한국국제농업개발학회 2012 韓國國際農業開發學會誌 Vol.24 No.3

The reason of poor germination rate of hamabo mallow seed was speculated using TZ test to determine the viability of seed. Seeds showed high viability via TZ test were not germinated well. The quiescent seeds did not imbibed properly due to the hard seed coat and did not show further processes required for germination. Several well-known treatments for seed coat loosening and water uptake into seed were applied and compared for their efficiency. Stratification, hot water treatment, seed coat scarification, wet-cold treatment were revealed as less effective for improving germination although those treatments were common method for breaking dormant seed. Chemical scarification with sulfuric acid, however, effectively increased germinability and promptness index of hamabo mallow seeds. Optimal time for sulfuric acid treatment was 20 min. Seeds treated for 20 min showed improved germination percentage, germination speed, and promptness index of 80%, 13, and 1969 at 30 days after imbibition, respectively, in petri dish experiment. The values were greater than control seeds showed low values (12%, 1, and 183, respectively). The similar tendency was observed in the pot experiment that sulfuric acid treated seed were sown in artificially mixed soil (loamy soil:peatmoss:sand:compost = 5:2:2:1) and placed in greenhouse. Ultrastructure analysis of chemically scarified seed with sulfuric acid for 20 min by scanning electron microscopy did not show any noticeable changes in seed coat hardness and water uptake via hilum. But the only change after sulfuric acid treatment was removal of hilum cap that close the hilum and hider imbibition. Therefore, subsequent experiment was conducted to know the relationship between removal of hilum cap and facilitated imbibition by sulfuric acid treatment and whether the hilum cap removal directly influenced to the opening of micropyle. Water uptake velocity of seed treated for 20 min in concentrated sulfuric acid for was greater than control seed. This result implies that the crucial effect of sulfuric acid treatment is the removal of hilum cap that increase water uptake via micropyle in hamabo mallow.

Ether-free polymeric anion exchange materials with extremely low vanadium ion permeability and outstanding cell performance for vanadium redox flow battery (VRFB) application

Cha, Min Suc,Jo, Sang Woo,Han, Seung Hui,Hong, Soo Hyun,So, Soonyong,Kim, Tae-Ho,Oh, Seong-Geun,Hong, Young Taik,Lee, Jang Yong Elsevier 2019 Journal of Power Sources Vol.413 No.-

<P><B>Abstract</B></P> <P>Ether-free poly(<I>p</I>-phenylene)-based anion exchange membrane materials with outstanding vanadium ion blocking properties are reported. The synthesized ionomers with a rigid backbone structure show small dimensional variations despite the high ion exchange capacities. Among the synthesized membranes, the QPPP-2 membrane with ion exchange capacity of 2.1 meq·g<SUP>−1</SUP> exhibits high anion (OH<SUP>−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>, and Cl<SUP>−</SUP>) conductivity. The QPPP-2 membrane shows an extremely low diffusion coefficient (2.12 × 10<SUP>−9</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>) for VO<SUP>2+</SUP>, which is much lower than that of Nafion 115 (2.88 × 10<SUP>−6</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>), indicating the vanadium ion blocking property of QPPP-2. Moreover, the chemical and operational stabilities of the membranes are investigated <I>via</I> ex situ soaking tests in 0.1 M VO<SUB>2</SUB> <SUP>+</SUP> solution and in situ operation tests for 100 cycles, respectively. The vanadium redox flow battery single cell assembled with the QPPP-2 membrane exhibits a coulombic efficiency of 99%, voltage efficiency of 87%, and energy efficiency of 86% during 100 cycles at 80 mA cm<SUP>−2</SUP>. The excellent chemical, morphological, and electrochemical properties of the QPPP-2 membrane make it suitable for use in vanadium redox flow battery.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AEMs are fabricated by a Ni(0)-catalyzed cross-coupling reaction. </LI> <LI> The synthesized ionomers indicated excellent dimensional and chemical stability. </LI> <LI> Ether-free polymeric AEMs showed extremely low vanadium ion cross over. </LI> <LI> The performance of developed AEM showed high EE (87%) with high capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microfluidic generation of Prussian blue-laden magnetic micro-adsorbents for cesium removal

Kang, Sung-Min,Rethinasabapathy, Muruganantham,Hwang, Seung Kuy,Lee, Go-Woon,Jang, Sung-Chan,Kwak, Cheol Hwan,Choe, Sang-Rak,Huh, Yun Suk Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.341 No.-

<P><B>Abstract</B></P> <P>Here, we designed and synthesized a recoverable multifunctional adsorbent using a microfluidic reaction system and evaluated the removal performance of the smart adsorbent toward radioactive cesium as a model sample. Prussian blue-laden magnetic micro-adsorbents (PB-MNPs-MAs) with uniform morphology and monodispersity were generated via two-step sequential procedures using a glass capillary microfluidic system, followed by chemical co-precipitation with a high production rate. The cesium removal efficacy of the PB-MNPs-MAs was analyzed based on Langmuir and Freundlich isotherms by controlling adsorption parameters such as adsorbent size, initial cesium concentration, and contact time. The adsorption isotherm of the PB-MNPs-MAs was better fitted to the Langmuir model with a maximum cesium adsorption capacity of 58.73 mg g<SUP>−1</SUP>, which was 40% higher than that of macro-adsorbents in a dynamic magnetic field. This result can be attributed to their large specific area, which increased the kinetic rate of cesium adsorption and achieved saturation within 20 min. Additionally, the PB-MNPs-MAs were recovered from wastewater within 5 s under a static magnetic field, indicating their great potential for magnetic actuation. We believe that our PB-MNPs-MAs can encapsulate nano-functional adsorbents and prevent actuation, making them promising for environmental remediation and especially for removal of radionuclides.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PB-MNPs-MAs were generated in microfluidic device using chemical co-precipitation. </LI> <LI> The prepared PB-MNPs-MAs are monodispersed with uniform morphology. </LI> <LI> PB-MNPs-MAs exhibited high Cs adsorption capacity (58.73 mg g<SUP>−1</SUP>). </LI> <LI> 100% recovery of PB-MNPs-MAs is possible under static magnetic field after Cs adsorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Development of electrochemical biosensor for detection of pathogenic microorganism in Asian dust events

Yoo, Min-Sang,Shin, Minguk,Kim, Younghun,Jang, Min,Choi, Yoon-E,Park, Si Jae,Choi, Jonghoon,Lee, Jinyoung,Park, Chulhwan Elsevier 2017 CHEMOSPHERE - Vol.175 No.-

<P><B>Abstract</B></P> <P>We developed a single-walled carbon nanotubes (SWCNTs)-based electrochemical biosensor for the detection of <I>Bacillus subtilis,</I> one of the microorganisms observed in Asian dust events, which causes respiratory diseases such as asthma and pneumonia. SWCNTs plays the role of a transducer in biological antigen/antibody reaction for the electrical signal while 1-pyrenebutanoic acid succinimidyl ester (1-PBSE) and ant-<I>B. subtilis</I> were performed as a chemical linker and an acceptor, respectively, for the adhesion of target microorganism in the developed biosensor. The detection range (10<SUP>2</SUP>–10<SUP>10</SUP> CFU/mL) and the detection limit (10<SUP>2</SUP> CFU/mL) of the developed biosensor were identified while the response time was 10 min. The amount of target <I>B. subtilis</I> was the highest in the specificity test of the developed biosensor, compared with the other tested microorganisms (<I>Staphylococcus aureus</I>, <I>Flavobacterium psychrolimnae</I>, and <I>Aquabacterium commune</I>). In addition, target <I>B. subtilis</I> detected by the developed biosensor was observed by scanning electron microscope (SEM) analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A SWCNTs-based biosensor was developed for the detection of <I>Bacillus subtilis.</I> </LI> <LI> The biosensor was composed of SWCNTs, 1-PBSE, and anti-<I>B. subtilis</I> antibody. </LI> <LI> The performance of the biosensor was assessed using a sensor sensitivity and specificity tests. </LI> <LI> The detection limit and detection range were 10<SUP>2</SUP> and 10<SUP>2</SUP>–10<SUP>10</SUP> CFU/mL, respectively. </LI> <LI> The detection time of the biosensor was identified as 10 min. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

갑상선 기능항진증 환자에서 인슐린감수성 및 인슐린분비능의 변화

최은진,강호철,이태희,정민영,이대호,장연진,박상선,조재현 대한내분비학회 1994 Endocrinology and metabolism Vol.9 No.2

The impairement of glucose metabolism is frequently associated in hyperthyroidism. The present study was performed to determine the effect of the thyroid hormone excess on insulin sensitivity and on insulin secretory function in vivo. Ten newly diagnosed hyperthyroid patients and fifteen healthy control subjects were subjected to frequently sampled intravenous glucose tolerance tests(FSIGT) after an overnight fast. Insulin sensitivity, represented by the insulin sensitivity index(S_1), was assessed by minimal model analysis of FSIGT data. Insulin secretion was measured by the total area under the insulin curve after glucose load. The results were as follows. 1) The K_G values, which represent glucose tolerance, were not different between the hyperthyroid patients and the normals(2.2+-0.3 vs. 2.5+-0.3%/min, p$gt;0.05). 2) S_1 was significantly decreased in the hyperthyroid patients in comparison to the normals(7.5+-1.4 vs. 2.6+-0.3X10^-4 min^-1/uU/ml, p$lt;0.05). 3) The basal insulin concentration was higher in the hyperthyroid patients than in the normals(8.3+-2.4 vs. 4.6+-0.4 uU/ml, p=0.07). In addition, the insulin secretory response to a glucose load was increased in the hyperthyroid patients as evidenced by the peak plasma insulin level(168.2+-30.4 vs. 89.2+-13.9 uU/ml, p$lt;0.05) and by the total area under the insulin curve(2641.1+-443.2 vs. 1696.7+-204.3 min uU/ml, p$lt;0.05). These results clearly demonstrated that insulin sensitivity was impaired in these newly diagnosed hyperthyroid patients. However, glucose tolerance was maintained by the increased insulin secretion (J Kor Soc Endocrinol 9:108-114, 1994).

구조 비선형성을 고려한 상태공간 천음속 날개꼴의 공력탄성해석

장민성,이종수 연세대학교 산업기술연구소 1999 논문집 Vol.31 No.2

An aeroelastic stability analysis is numerically simulated for two-degree-of-freedom transonic airfoils with some structural nonlinearities in torsional stiffness. A state-space method is used to model the characteristic values of the unsteady transonic flow. Structural nonlinearities considered in the present study are free-play, bilinear spring and friction. The stability of the aeroelastic system is determined by converging values of the angle of attack and bending displacement in time domain. The flutter behavior and vibratory amplitudes are examined for a number of flight conditions and airfoil geometry configurations.

이산화된 탐색공간에서 다구찌 방법을 이용한 구조 최적설계에 관한 연구

장성현,정우영,정용민,권봉철,최영휴 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

Nowadays, there are several design problem having discrete variables in the industrial fields. The researchers are using the optimization method, such as genetic algorithm (GA), simulated annealing (SA), design of experiment (DOE) and taguchi method (TM), to solve it's design problem. Moreover, people want to decrease the computational cost and time. Therefore, in this paper, we proposed the iterative optimization algorithm which repetitively searched a local region to find best solution in discrete searching space using TM. The optimal solution in each local region is obtained by S/N ratio for the evaluation function that consists of the objective function and penalty function. Also, we have applied our algorithm to 3-bar, 10-bar, and 25-bar truss optimization problem.

로봇 비젼 제어를 위한 확장 칼만 필터링 모델 개발

장완식,박성일,이성민,김기영,신광수 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.2

The computational time in estimating the parameter of vision control algorithm is very important for robot's position control in real time. Unfortunately, the batch estimation used commonly requires much computational time because it has iteration method. So, the batch estimation has difficulty for robot's position control in real time. On the other hand, the Extended Kalman Filtering(EKF) has much advantages in that it is a simple and efficient recursive procedures. Thus, this study is to develop the EKF algorithm for the robot's vision control in real time. This vision system used in this study involves the six parameters to account for the camera inner (orientation, focal length etc) and outer parameters (the relative location between robot and camera). Then, EKF is applied to estimate these parameters, and based on estimated these parameters, EKF also is applied to estimate the robot's joint angles used for robot's operation. Finally, Experiment on the robot's position control is performed to show the practicality of vision control scheme based on the EKF.

전류제어형 PWM컨버터를 이용한 동기발전기용 여자시스템에 관한 연구

장수진,류동균,서민성,김준호,원충연,이진국 성균관대학교 2003 학술회의지원논문목록집 Vol.2003 No.-

동기발전기 출력전압은 여자시스템의 계자전류 제어에 의해 일정하게 유지된다. 고주파 PWM 컨버터(전류제어모드 buck컨버더)형태의 여자시스템은 부하변동이 발생하였을 때 동기발전기의 계자전류를 제어하게 된다. 이 논문은 정상상태 및 과도상태에서의 안정화를 개선하기 위하여 여자시스템의 설계 및 실험에 대해 다루었다. 시뮬레이션 및 실험 결과는 제안된 여자시스템이 50kW 동기발전기의 DVR에 의해 응답시간이 개선되었음을 보여주었다. The output voltage of synchronous generator is regulated constantly by field current control in excitation system. High frequency PWM converter (current control mode buck conveter) type excitation system for synchronous generator is able to control exciter current when the load change happened. This paper deals with the design and evaluation of the excitation system for a synchronous generator to improve the steady state and transient stability. The simulation and experimental results show that the proposed excitation system is able to improve the response time by the DVR(digital voltage regulator) of 5O[kW] synchronous generator.

히알루로란이 동종골 이식술시 골 형성 과정에 미치는 영향에 관한 연구

민승기,김종구,장성홍 大韓顎顔面成形再建外科學會 2003 Maxillofacial Plastic Reconstructive Surgery Vol.25 No.2

Hyaouronan is an essential component of extracellular matrices. Early in embryogenesis mesenchymal cells migrate, proliferate and differentiate, in part, because of the influence of hyaouronan. Since the features of embryogenesis are revisited during wound healing, including bone fracture repair, this study was initiated to evaluate whether hyaouronan has an effect on osteogenesis in early stage of wound healing. Grafting bone chip was applied on the two squared bone defects on the total 60 rat calvarium about 7×7㎜ size which were made with electric dill intentionally, the right side was graft allogeneic bone and left side was autogenous bone grafting. In experimental groups, grafting materials were hydrated with 1.0㎎/㎖ concentration of hyaouronan solution before surgery for 30 minutes. The calvarial bone defects were covered with layer suture. In postoperative 1,2,4,6 and 8 weeks, total experimental rats were sacrificed and eveluated under light microscope with routine H&E, Masson Trichrome and toluidine boue stain and found initial osteogenesis at postoperative 1 and 2 weeks, inflammatory changes in the wound sites were more prominemt in bones to which hyaouronan had been applied. But, new bone formation had been induced by day 7 on both peri- and endosteal surfaces of the grafted areas. newly formed trabecular bines were till postoperative 4 weeks. The mature bone formation on both calvarial bone defects after 4 weeks without distinctive difference between control and hyaouronan groups. These results suggest that high0molecular hyaouronan is capable of asselerating new bone formation through mesenchymal cell differentiation in bone grafting.