Solar Cells: Amorphous Zinc Stannate (Zn₂SnO₄) Nanofibers Networks as Photoelectrodes for Organic Dye‐Sensitized Solar Cells (Adv. Funct. Mater. 25/2013)

Choi, Seung‐,Hoon,Hwang, Daesub,Kim, Dong‐,Young,Kervella, Yann,Maldivi, Pascale,Jang, Sung‐,Yeon,Demadrille, Renaud,Kim, Il‐,Doo WILEY‐VCH Verlag 2013 Advanced Functional Materials Vol.23 No.25

<P>Highly porous amorphous Zn<SUB>2</SUB>SnO<SUB>4</SUB> electrodes are prepared using electrospinning techniques and combined with organic or ruthenium dyes to fabricate dye‐sensitized solar cells. As reported by Sung‐Yeon Jang, Renaud Demadrille, Il‐Doo Kim, and co‐workers on page 3146, the devices based on 3‐μm‐thick electrodes and the organic dyes demonstrate significantly improved performances compared to those using the ruthenium complex. Using this approach, solar cells with power conversion efficiencies up to 3.7% are obtained. </P>

압축성 코드에서 예조건화 코드로의 이진

한상훈(Sang-Hoon Han),김명호(Myeong-Ho Kim),최정열(Jeong-Yeol Choi) 한국항공우주학회 2007 韓國航空宇宙學會誌 Vol.35 No.3

이차원 범프 유동에 대한 다양한 예조건화 행렬의 수렴 특성을 살펴 Choi와 Merkle의 예조건화 행렬을 선택하여, 압축성 및 예조건화 Roe의 Riemann 해법의 수치 소산항을 수학적으로 비교하였다. 이 결과 코드의 구조는 동일하게 유지한 채, 고유치의 작은 수정만으로 압축성 해법을 예조건화 해법으로 이전할 수 있는 방법을 알 수 있었다. 아울러 점성 유동 영역에서의 안정성 및 정확성을 향상시키기 위하여 von Neumann 안정 조건 및 점성 자코비안을 고려하였으며, 개발된 코드는 표준 검증 문제에 적용하여 검증을 수행하였다. Comprehensive mathematical comparison of numerical dissipation vector was made for a compressible and the preconditioned version Roe's Riemann solvers. Choi and Merkle type preconditioning method was selected from the investigation of the convergence characteristics of the various preconditioning methods for the flows over a two-dimensional bump. The investigation suggests a way of migration from a compressible code to a preconditioning code with a minor changes in Eigenvalues while maintaining the same code structure. Von Neumann stability condition and viscous Jacobian were considered additionally to improve the stability and accuracy for the viscous flow analysis. The developed code was validated through the applications to the standard validation problems.

최씨 훅을 이용한 복강경 버찌씨 수술

김영혜 ( Young Hye Kim ),박준선 ( Jun Seon Park ),최상준 ( Sang Joon Choi ),송창훈 ( Chang Hoon Song ),한세준 ( Sei Jun Han ),정혁 ( Hyuk Jung ) 대한산부인과학회 2006 Obstetrics & Gynecology Science Vol.49 No.6

목적: 버찌씨 수술은 복압성 요실금 수술에 효과적인 수술로 여겨져 왔다. 요실금의 원인이 내인성 요도 괄약근의 결손소견 없이 요도의 과운동성으로 인한 경우 버찌씨 수술이 일반적으로 추천되어진다. 본 연구에서는 복강경 버찌씨 수술에서 최씨 훅의 유용성에 대해 알아보고자 하였다. 연구방법: 2000년 10월부터 2005년 3월까지 본원에서 복강경 버찌씨 수술을 시행받은 47명의 환자를 대상으로 하였다. 27명은 고전적 복강경 버찌씨 수술을 시행하였고 20명은 내골반 근막을 Cooper 인대를 부착하는데 유용한 본원에서 고안한 최씨 훅을 이용하여 복강경 버찌씨 수술을 시행하였다. 결과: 고전적 복강경 버찌씨 수술을 시행한 군과 최씨 훅을 이용한 복강경 버찌씨 수술을 시행한 군의 평균 나이, 분만력, 폐경률, BMI는 두 군간에 통계학적으로 유의한 차이를 보이지 않았다 (p>0.05). 수술 시간은 고전적 복강경 버찌씨 수술은 90.52±15.32분, 최씨 훅을 이용한 복강경 버찌씨 수술은 38.50±10.14분으로 최씨 훅을 이용한 경우 수술시간이 통계적으로 유의하게 짧았다 (p<0.05). 두 군간에 재발률 및 합병증 발생은 통계적 유의성을 보이지 않았다 (p>0.05). 결론: 본 연구에서 본원에서 고안한 최씨 훅을 이용하여 복강경 버찌씨 수술을 시행한 결과 수술 시간을 단축시킬 수 있었으며 수술 효과는 기존 방법과 동일하게 관찰되었다. 이에 최씨 훅은 복강경 버찌씨 수술에서 사용할 때 집도자의 봉합 과정을 단순화시켜 수술 시간을 단축시키므로 복강경 버찌씨 수술에 용이한 기구이다. Objective: Burch operation has been effective method for the treatment of stress incontinence. Burch operation is a well-accepted procedure for treating stress urinary incontinence secondary to urethral hypermobility without intrinsic sphincter deficiency and is the reference standard with which other procedures are compared. This study is to evaluate the effectiveness of the Choi`s hook in laparoscopic Burch operation. Methods: This study included 47 patients who had undergone laparoscopic Burch operation from October 2000 through March 2005. Of these 47 patients, 27 patients underwent traditional laparoscopic Burch operation (Group 1) and 20 patients underwent laparoscopic Burch operation with Choi`s Hook on anchoring the endopelvic fascia to the Cooper`s ligament (Group 2). Results: The mean age of patients of Group 1 was 55.6±9.37 years of age and that of Group 2 was 56.0±5.93 years of age. There is no difference in the mean age of patients (P>0.05). The mean operating time was 90.5±15.32 minutes for Group 1 and 38.5±10.14 minute for Group 2. The mean operating time was shorter in Group 2 than Group 1 (P<0.05). There was no difference in recurrence rate and complication rate between Group 1 and Group 2 (P>0.05). Conclusion: We performed laparoscopic Burch operation with the Choi`s Hook on anchoring the endopelvic fascia to the Cooper`s ligament. When we compared traditional laparoscopic Burch operation with laparoscopic Burch operation with Choi`s Hook, we could shorten the operation time using the Choi`s Hook.

CO₂ Absorption and Desorption in an Aqueous Solution of Heavily Hindered Alkanolamine: Structural Elucidation of CO₂-Containing Species

Choi, Young-Seop,Im, Jinkyu,Jeong, Jun Kyo,Hong, Sung Yun,Jang, Ho Gyeom,Cheong, Minserk,Lee, Je Seung,Kim, Hoon Sik American Chemical Society 2014 Environmental science & technology Vol.48 No.7

<P>The pathways for the CO<SUB>2</SUB> absorption and desorption in an aqueous solution of a heavily hindered alkanolamine, 2-(<I>t</I>-butylamino)ethanol (TBAE) were elucidated by X-ray crystallographic and <SUP>13</SUP>C NMR spectroscopic analysis. In the early stage of the CO<SUB>2</SUB> absorption, the formation of carbonate species ([TBAEH]<SUB>2</SUB>CO<SUB>3</SUB>) was predominant, along with the generation of small amounts of zwitterionic species. With the progress of the absorption, the carbonate species was rapidly transformed into bicarbonate species ([TBAEH]HCO<SUB>3</SUB>), and the amounts of the zwitterionic species increased gradually. During desorption at elevated temperature in the absence of CO<SUB>2</SUB>, [TBAEH]HCO<SUB>3</SUB> was found to transform into [TBAEH]<SUB>2</SUB>CO<SUB>3</SUB>, where CO<SUB>3</SUB><SUP>2–</SUP> strongly interacts with two [TBAEH]<SUP>+</SUP> via hydrogen bondings.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2014/esthag.2014.48.issue-7/es405036m/production/images/medium/es-2013-05036m_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es405036m'>ACS Electronic Supporting Info</A></P>

Static and Dynamic FEM Simulation of Packaging Tray Cup Pad for Korean Pears

Choi, Dong-Soo,Son, Jea-Yong,Kim, Jin-Se,Kim, Yong-Hoon,Park, Chun-Wan,Jung, Hyun-Mo,Hwang, Sung-Wook Korea Society of Packaging Science and Technology 2019 한국포장학회지 Vol.25 No.3

Among the many packaging materials used in cushion packaging, there is a lack of optimum design for the tray cup pad used in fruit packaging for export and domestic distribution. It causes over-packaging due to excessive material input, and this could be solved by applying various parameters needed to optimize the design of the tray cup pad considering the packaging material and the quantity of fruits in the box. In the case of a tray cup for fruits, the economic efficiency of material and thickness should be considered. Therefore, it is possible to design a tray cup pad depending on the packaging material used by applying appropriate design parameters. The static and dynamic characteristics of the materials used for packaging of pears were analyzed by using the FEM (finite element Method) simulation technique to derive the optimal design parameters. And by applying the appropriate design parameters considering the quantity of fruit and distribution environment, it is possible to design an appropriate fruit tray cup pad. In this study, as a result of simulating the contact stresses between the fruit and the tray cup for the PP, PE, and PS materials used in the fruit tray cup, the material with the lowest contact stress was PP and the value was found to be 398 Pa. The contact displacement between fruit and tray cup using this material was about 0.0463 mm, which was the lowest value compared with other materials. Also the resonance frequency band of tray cup made of PP material was below 36.81 Hz, and the strain energy was below 12.20 J. The resonant frequency band of the pear is more than 80 Hz and it could be applied to all the tray cup materials as compared with the resonance band of 38.81 Hz or less which is the resonance band of all tray cup pads for packaging. Finally, PP is the most suitable material for the tray cup pad.

A Flowmeter with Piezoresistive Metal Layer Deposited with Focused-Ion-Beam System

Choi, Dae Keun,Lee, Sang Hoon Taylor Francis 2014 Integrated ferroelectrics Vol.157 No.1

The Expression of Adipogenic Genes in Adipose Tissues of Feedlot Steers Fed Supplementary Palm Oil or Soybean Oil

Choi, Seong Ho,Park, Sung Kwon,Choi, Chang Weon,Li, Xiang Zi,Kim, Kyoung Hoon,Kim, Won Young,Jeong, Joon,Johnson, Bradley J.,Zan, Linsen,Smith, Stephen B. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.3

We hypothesized that supplementing finishing diets with palm oil would promote adipogenic gene expression and stearoyl-CoA desaturase (SCD) gene expression in subcutaneous (s.c.) and intramuscular (i.m.) adipose tissues of feedlot steers. Eighteen Angus and Angus crossbred steers were assigned to three groups of 6 steers and fed a basal diet (control), with 3% palm oil, or with 3% soybean oil, for 70 d, top-dressed daily. Tailhead s.c. adipose tissue was obtained by biopsy at 14 d before the initiation of dietary treatments and at 35 d of dietary treatments. At slaughter, after 70 d of dietary treatment, tailhead s.c. adipose tissue and i.m. adipose tissue were obtained from the longissimus thoracis muscle. Palm oil increased plasma palmitic acid and soybean oil increased plasma linoleic acid and ${\alpha}$-linolenic acid relative to the initial sampling time. Expression of AMP-activated protein kinase alpha ($AMPK{\alpha}$) and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) increased between the initial and intermediate biopsies and declined thereafter (p<0.03). SCD gene expression did not change between the initial and intermediate biopsies but declined by over 75% by the final period (p = 0.04), and G-coupled protein receptor 43 (GPR43) gene expression was unaffected by diet or time on trial. Soybean oil decreased (p = 0.01) $PPAR{\gamma}$ gene expression at the intermediate sample time. At the terminal sample time, $PPAR{\gamma}$ and SCD gene expression was less in i.m. adipose tissue than in s.c. adipose tissue (p<0.05). $AMPK{\alpha}$ gene expression was less in s.c. adipose tissue of palm oil-fed steers than in control steers (p = 0.04) and CCAAT enhancer binding protein-beta ($CEBP{\beta}$) gene expression was less in s.c. and i.m. adipose tissues of palm oil-fed steers than in soybean oil-fed steers (p<0.03). Soybean oil decreased SCD gene expression in s.c. adipose tissue (p = 0.05); SCD gene expression in palm oil-fed steers was intermediate between control and soybean oil-fed steers. Contrary to our original hypothesis, palm oil did not promote adipogenic gene expression in s.c. and i.m. adipose tissue.

Vasoconstriction Potency Induced by Aminoamide Local Anesthetics Correlates with Lipid Solubility

Sung, Hui-Jin,Ok, Seong-Ho,Sohn, Jin-Young,Son, Yong Hyeok,Kim, Jun Kyu,Lee, Soo Hee,Han, Jeong Yeol,Lim, Dong Hoon,Shin, Il-Woo,Lee, Heon-Keun,Chung, Young-Kyun,Choi, Mun-Jeoung,Sohn, Ju-Tae Hindawi Publishing Corporation 2012 Journal of biomedicine & biotechnology Vol.2012 No.-

<P>Aminoamide local anesthetics induce vasoconstriction <I>in vivo</I> and <I>in vitro</I>. The goals of this <I>in vitro</I> study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency) of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine) were obtained from isolated rat aorta. Regression analyses were performed to determine the relationship between the reported physicochemical properties of local anesthetics and the local anesthetic concentration that produced 50% (ED<SUB>50</SUB>) of the local anesthetic-induced maximum vasoconstriction. We determined the order of potency (ED<SUB>50</SUB>) of vasoconstriction among local anesthetics to be levobupivacaine > ropivacaine > lidocaine > mepivacaine. The relative importance of the independent variables that affect the vasoconstriction potency is octanol/buffer partition coefficient > potency > pKa > molecular weight. The ED<SUB>50</SUB> in endothelium-denuded aorta negatively correlated with the octanol/buffer partition coefficient of local anesthetics (<I>r</I><SUP>2</SUP> = 0.9563; <I>P</I> < 0.001). The potency of the vasoconstriction in the endothelium-denuded aorta induced by local anesthetics is determined primarily by lipid solubility and, in part, by other physicochemical properties including potency and pKa.</P>

Relationship between Trading Volume and Asymmetric Volatility in the Korean Stock Market

Choi, Ki-Hong,Jiang, Zhu-Hua,Kang, Sang Hoon,Yoon, Seong-Min 'Scientific Research Publishing, Inc.' 2012 Modern Economy Vol.3 No.5

Safety of Barbed Suture Material for Wound Closure in Single Incisional Cholecystectomy

( Sung Yub Jeong ),( Sung Hoon Choi ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1

Aims: Single incisional cholecystectomy is surgical methods that provide comparable results to standard laparoscopic cholecystectomy (LC). However, single incisional cholecystectomy has been accused for post-operative incisional hernia. The incidence of incisional hernia after single incisional cholecystectomy is reported at 2.2% to 2.4% in short-term follow-up studies and up to 10.9% in long-term follow-up. One of incisional hernia’s risk factor is surgical technique failure during wound closure. This study evaluated the incidence of patients developing incisional hernia after single incisional cholecystectomy, and we hope to suggest a solution in overcoming incisional hernia arising out surgical technique failure by using barbed suture material during wound closure. Methods: Total number of 984 patients underwent single incisional cholecystectomy between March 2014 and December 2019. During this period, there were 689 patients who underwent wound closure with non-barbed suture material (Monosyn ○R) and 295 patients with barbed suture material (StratafixTM). Both Patient groups were comparable in age, gender, BMI, ASA score and total operation. Results: 2 patients (0.3%) developed an incisional hernia in non-barbed suture group and none in the barbed suture group. The incidence of incisional hernia was higher in the non-barbed suture group (0.3% versus 0%), but statistically insignificant. (P=1.00). Conclusions: Our large volume study showed lower incidence of incisional hernia (0.3%) to comparing previous studies. Also, there was no incisional hernia patient in barbed suture group, although statistically insignificant, which means possibility of overcoming the surgical technique failure using barbed suture material. We hope to share our experience on safety and advantage of using barbed suture.