Study on Peak Current Limiting Characteristics of a Flux-Lock Type SFCL Using Its Third Winding

Sung-Hun Lim,Il-Kyoung You,Jae-Chul Kim IEEE 2011 IEEE transactions on applied superconductivity Vol.21 No.3

<P>Generally, the peak amplitude of the fault current after the fault occurrence depends on the transient component of the fault current, which is determined by the fault condition such as the fault angle. In the suggested flux-lock type superconducting fault current limiter (SFCL), the fault current of the lower peak amplitude causes the only high-T<SUB>C</SUB> superconducting (HTSC) element connected in series with one of two coils comprising the flux-lock type SFCL to be quenched, which the fault current can be limited by the lower limiting impedance of the flux-lock type SFCL. On the other hand, the fault current with the higher peak amplitude makes another HTSC element connected with the third winding to be quenched after the HTSC element connected in series with one of the SFCL's two coils is quenched, which contributes to the higher limiting impedance of this SFCL. Therefore, the effective fault current limiting operation of the flux-lock type SFCL can be performed by generating the SFCL's limiting impedance in proportion to the peak amplitude of the fault current. To confirm the current limiting operation of the proposed flux-lock type SFCL, the short-circuit tests of the flux-lock type SFCL using its third winding according to the fault angle were carried out and its effective fault current limiting operations were discussed.</P>

Preparation and evaluation of polymeric microparticulates for improving cellular uptake of gemcitabine

Lim, Ji-Ho,You, Sung-Kyun,Baek, Jong-Suep,Hwang, Chan-Ju,Na, Young-Guk,Shin, Sang-Chul,Cho, Cheong-Weon Dove Medical Press 2012 International journal of nanomedicine Vol.7 No.-

<P><B>Background</B></P><P>Gemcitabine must be administered at high doses to elicit the required therapeutic response because of its very short plasma half-life due to rapid metabolism. These high doses can have severe adverse effects.</P><P><B>Methods</B></P><P>In this study, polymeric microparticulate systems of gemcitabine were prepared using chitosan as a mucoadhesive polymer and Eudragit L100-55 as an enteric copolymer. The physicochemical and biopharmaceutical properties of the resulting systems were then evaluated.</P><P><B>Results</B></P><P>There was no endothermic peak for gemcitabine in any of the polymeric gemcitabine microparticulate systems, suggesting that gemcitabine was bound to chitosan and Eudragit L100-55 and its crystallinity was changed into an amorphous form. The polymeric gemcitabine microparticulate system showed more than 80% release of gemcitabine in 30 minutes in simulated intestinal fluid. When mucin particles were incubated with gemcitabine polymeric microparticulates, the zeta potential of the mucin particles was increased to 1.57 mV, indicating that the polymeric gemcitabine microparticulates were attached to the mucin particles. Furthermore, the F53 polymeric gemcitabine microparticulates having 150 mg of chitosan showed a 3.8-fold increased uptake of gemcitabine into Caco-2 cells over 72 hours compared with gemcitabine solution alone.</P><P><B>Conclusion</B></P><P>Overall, these results suggest that polymeric gemcitabine microparticulate systems could be used as carriers to help oral absorption of gemcitabine.</P>

Andrographolide induces apoptotic and non-apoptotic death and enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in gastric cancer cells

Lim, Sung-Chul,Jeon, Ho Jong,Kee, Keun Hong,Lee, Mi Ja,Hong, Ran,Han, Song Iy Spandidos Publications 2017 Oncology letters Vol.13 No.5

Site Preference and Hyperfine Structure in Doped Z-Type Hexaferrite Ba_1.5Sr_1.5Co₂(Fe_1–<i>x</i>Al_<i>x</i>)₂₄O₄₁ Investigated by Mössbauer Spectroscopy

Lim, Jung Tae,Kim, Chul Sung IEEE 2017 IEEE transactions on magnetics Vol.53 No.11

<P>The Ba1.5Sr1.5Co2(Fe1-xAlx)(24)O-41 (x = 0, 0.01, 0.03, and 0.05) polycrystalline samples were synthesized by the polymerizable complex method. Based on the Rietveld refinement, the crystal structures of samples were found to be single phased and determined to be rhombohedral with space group of P-63/mmc. The hysteresis curves of these samples were measured under 20 kOe at 295 K, showing that they were not saturated with increasing Al ion contents because spin structure was modified due to the reduction of magnetic anisotropy. With increasing Al ions contents, the value of M20kOe decreases due to the preferential occupation of non-magnetic Al ions in the up-spin site, while Hc increases. The Mossbauer spectra of the samples were obtained at 295 K, and analyzed as six distinguishable sextets (4f(IV), 4f(IV)*, 12k(V I)*, 4f(V I)* + 4e(IV), 12k(V I), and 2d(V) + 2a(V I) + 4f(V I) + 4e(V I)) below T-C due to the superposition of ten sextets of Fe sites corresponding to the Z-type hexagonal ferrite. The occupation number of up-spin site decreases with increasing Al ions. This suggests that the Al ions preferentially occupy the tetrahedral sublattices, leading to decrease in M-20kOe.</P>

Control and Switching of Aromaticity in Various All-Aza-Expanded Porphyrins: Spectroscopic and Theoretical Analyses

Sung, Young Mo,Oh, Juwon,Cha, Won-Young,Kim, Woojae,Lim, Jong Min,Yoon, Min-Chul,Kim, Dongho American Chemical Society [etc.] 2017 Chemical reviews Vol.117 No.4

<P>Modification of aromaticity is regarded as one of the most interesting and important research topics in the field of physical organic chemistry. Particularly, porphyrins and their analogues (porphyrinoids) are attractive molecules for exploring various types of aromaticity because most porphyrinoids exhibit circular conjugation pathways in their macrocyclic rings with various molecular structures. Aromaticity in porphyrinoids is significantly affected by structural modification, redox chemistry, NH tautomerization, and electronic states (singlet and triplet excited states). Conversely, aromaticity significantly affects the spectroscopic properties and chemical reactivities of porphyrinoids. In this context, considerable efforts have been devoted to understanding and controlling the aromaticity and antiaromaticity of porphyrinoids. Thus, a series of porphyrinoids are in the limelight, being expected to shed light on this field because they have some advantages to demonstrate the switching of aromaticity; it is possible to control the aromaticity by lowering the temperature, adding and removing the protons of expanded porphyrins, changing the chemical environment, and switching the electronic states (triplet and singlet excited states) by photoexcitation. In this regard, this Review describes the control of aromaticity in various expanded porphyrins from the spectroscopic point of view with assistance from theoretical calculations.</P>

Acute Displaced Fracture of Lateral Acromion after Reverse Shoulder Arthroplasty: A Case Report and Surgical Technique

Chul-Hyun Cho,Jae-Won Jung,Young-Jae Lim,Sang-Soo Na,Du-Han Kim 대한견주관절학회 2019 대한견주관절의학회지 Vol.22 No.2

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress frac-tures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treat-ment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle pre-contoured plate.

Efficacy of p16 and Ki-67 immunostaining in the detection of squamous intraepithelial lesions in a high-risk HPV group

LIM, SHARON,LEE, MI JA,CHO, INJU,HONG, RAN,LIM, SUNG CHUL Spandidos Publications 2016 Oncology letters Vol.11 No.2

Analysis on the Multi-Constellation SBAS Performance of SDCM in Korea

Lim, Cheol-Soon,Park, Byungwoon,So, Hyoungmin,Jang, Jaegyu,Seo, Seungwoo,Park, Junpyo,Bu, Sung-Chun,Lee, Chul-Soo The Institute of Positioning 2016 Journal of Positioning, Navigation, and Timing Vol.5 No.4

A Satellite Based Augmentation System (SBAS) provides differential correction and integrity information through geostationary satellite to users in order to reduce Global Navigation Satellite System (GNSS)-related errors such as ionospheric delay and tropospheric delay, and satellite orbit and clock errors and calculate a protection level of the calculated location. A SBAS is a system, which has been set as an international standard by the International Civilian Aviation Organization (ICAO) to be utilized for safe operation of aircrafts. Currently, the Wide Area Augmentation System (WAAS) in the USA, the European Geostationary Navigation Overlay Service (EGNOS) in Europe, MTSAT Satellite Augmentation System (MSAS) in Japan, and GPS-Aided Geo Augmented Navigation (GAGAN) are operated. The System for Differential Correction and Monitoring (SDCM) in Russia is now under construction and testing. All SBASs that are currently under operation including the WAAS in the USA provide correction and integrity information about the Global Positioning System (GPS) whereas the SDCM in Russia that started SBAS-related test services in Russia in recent years provides correction and integrity information about not only the GPS but also the GLONASS. Currently, LUCH-5A(PRN 140), LUCH-5B(PRN 125), and LUCH-5V(PRN 141) are assigned and used as geostationary satellites for the SDCM. Among them, PRN 140 satellite is now broadcasting SBAS test messages for SDCM test services. In particular, since messages broadcast by PRN 140 satellite are received in Korea as well, performance analysis on GPS/GLONASS Multi-Constellation SBAS using the SDCM can be possible. The present paper generated correction and integrity information about GPS and GLONASS using SDCM messages broadcast by the PRN 140 satellite, and performed analysis on GPS/GLONASS Multi-Constellation SBAS performance and APV-I availability by applying GPS and GLONASS observation data received from multiple reference stations, which were operated in the National Geographic Information Institute (NGII) for performance analysis on GPS/GLONASS Multi-Constellation SBAS according to user locations inside South Korea utilizing the above-calculated information.

Applying Novel Nutrient Drink to Clinical Trial of Functional Dyspepsia

( Chul Hyun Lim ),( Myung Gyu Choi ),( Myong Ki Baeg ),( Sung Jin Moon ),( Jin Su Kim ),( Yu Kyung Cho ),( Jae Myung Park ),( In Seok Lee ),( Sang Woo Kim ),( Kyu Yong Choi ) 대한소화기기능성질환·운동학회 2014 Journal of Neurogastroenterology and Motility (JNM Vol.20 No.2

Background/AimsThe drink test has been regarded as a surrogate marker of gastric accommodation. The aims of this study were to develop anovel nutrient drink test (NDT) protocol and investigate its potential for application to a clinical trial of functional dyspepsia (FD). MethodsA novel NDT was designed, involving drinking 125 mL of nutrient 4 times at 5-minute intervals or until maximal tolerability. Healthy volunteers and patients with FD rated their symptoms every 5 minutes for 20 minutes in a developmental study. Patients with FD were enrolled in an open trial of itopride for 4 weeks. NDT was performed before and after treatment. Improvement of integrative symptoms score during NDT after treatment for more than 50% compared with baseline was definedas responder. ResultsTotal aggregate symptom scores, sum of symptom scores measured during NDT, were higher in FD patients (n = 40, 368.1± 245.3) than in controls (n = 19, 215.9 ± 171.2) (P = 0.018) in a developmental study. In an open trial of itopride, symptomscores measured during NDT decreased significantly at all time points after treatment in responders (n = 49), whereas didnot in non-responders (n = 25). Total aggregate symptom score for NDT correlated significantly with integrative dyspepticsymptom score, sum of 8 symptom scores of NDI questionnaire, at baseline (r = 0.374, P = 0.001) and after treatment (r= 0.480, P < 0.001). ConclusionsOur novel NDT can quantify dyspeptic symptoms and reflected therapeutic effects of itopride treatment in a clinical trial of FDpatients. This NDT can be used as an effective parameter in clinical trials or drug development programs for assessing effectsof novel therapies on postprandial symptoms.

Evaluation of a Laser Altimeter using the Pseudo-Random Noise Modulation Technique for Apophis Mission

Lim, Hyung-Chul,Sung, Ki-Pyoung,Choi, Mansoo,Park, Jong Uk,Choi, Chul-Sung,Bang, Seong-Cheol,Choi, Young-Jun,Moon, Hong-Kyu The Korean Space Science Society 2021 Journal of astronomy and space sciences Vol.38 No.3

Apophis is a near-Earth object with a diameter of approximately 340 m, which will come closer to the Earth than a geostationary orbit in 2029, offering a unique opportunity for characterizing the object during the upcoming encounter. Therefore, Korea Astronomy and Space Science Institute has a plan to propose a space mission to explore the Apophis asteroid using scientific instruments such as a laser altimeter. In this study, we evaluate the performance metrics of a laser altimeter using a pseudorandom noise modulation technique for the Apophis mission, in terms of detection probability and ranging accuracy. The closed-form expression of detection probability is provided using the cross correlation between the received pulse trains and pseudo-random binary sequence. And the new ranging accuracy model using Gaussian error propagation is also derived by considering the sampling rate. The operation range is significantly limited by thermal noise rather than background noise, owing to not only the low power laser but also the avalanche photodiode in the analog mode operation. However, it is demonstrated from the numerical simulation that the laser altimeter can achieve the ranging performance required for a proximity operation mode, which employs commercially available components onboard CubeSat-scale satellites for optical communications.