A Study of the PV System for Optimum Design Methods With Loss Parameter Compensation

Kang-Yeon Lee,Moon-Han Choi,Youn-Ok Choi,Byeong-Ho Joeng,Geum-Bae Cho 한국조명·전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.9

Photovoltaic systems utilize the infinite clean energy of the sun, without creating any air pollution or noise and mechanical vibration. A PV system operates without the need of fuel, rotation surfaces, high temperatures or high pressures. It is therefore to do maintain and simple to install as well as having a long life cycle. The global market for PV systems continues to grow rapidly by 30[%] per year. This paper suggests a new design method for the PV system installation that will allow to the improvement of system efficiency. This method is in accordance with the loss parameter compensation method designed for the PV systems and investigated through simulation and practical experimentation. It was applied to an interconnected 10[㎾] grid PV system and was demonstrated in the field. Features such as solar array, KS, system efficiency, performance and stability were considered. Through the proposed optimal parameter design method, the features of the system were studied, and the 10[㎾] PV system was demonstrated and analyzed.

Comparisons of Precision Measurement Methods for Metallic Resistivities

Kang, Jeon Hong,Yu, Kwang Min,Kim, Han Jun,Ryu, Je Cheon,Han, Sang Ok Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.321 No.-

<P>As widely-used methods to measure metallic resistivities, Four-terminal method, van der Pauw method, Four-Point Probe(FPP) method and eddy current method were compared and analysed to find the method with lowest uncertainty and accurate method for applying nondestructively to industry. STS 316, non-magnetic metal is used as sample for the four methods. Conductivity ratios by the four-terminal method and van der Pauw method had the lowest uncertainty of 0.25 % and the ratios by the FPP method had measurement uncertainty of 0.45 % when probe spacing was more than two times of sample thickness and dc 10 A is applied. Also, the ratio values by the eddy current method had 1 % or more difference from the four-terminal or van der Pauw method and measurement uncertainty was obtained as 0.93 %. From the results, former two methods had the lowest uncertainty but are destructive methods so that those are difficult to apply to the field of industry. The FPP method is an accurate and nondestructive measurement method so that it can be used in the field. The eddy current method is one of nondestructive method but it has the highest uncertainty and low accuracy.</P>

Current Status, Challenges, Policies, and Bioethics of Biobanks

Kang, Byunghak,Park, Jaesun,Cho, Sangyun,Lee, Meehee,Kim, Namhee,Min, Haesook,Lee, Sooyoun,Park, Ok,Han, Bokghee Korea Genome Organization 2013 Genomics & informatics Vol.11 No.4

Many biobanks were established as biorepositories for biomedical research, and a number of biobanks were founded in the 1990s. The main aim of the biobank is to store and to maintain biomaterials for studying chronic disease, identifying risk factors of specific diseases, and applying personalized drug therapies. This report provides a review of biobanks, including Korean biobanks and an analysis of sample volumes, regulations, policies, and ethical issues of the biobank. Until now, the top 6 countries according to the number of large-scale biobanks are the United Kingdom, United States, Sweden, France, the Netherlands, and Italy, and there is one major National Biobank of Korea (NBK) and 17 regional biobanks in Korea. Many countries have regulations and guidelines for the biobanks, and the importance of good management of biobanks is increasing. Meanwhile, according to a first survey of 456 biobank managers in the United States, biobankers are concerned with the underuse of the samples in their repositories, which need to be advertised for researchers. Korea Biobank Network (KBN) project phase II (2013-2015) was also planned for the promotion to use biospecimens in the KBN. The KBN is continuously introducing for researchers to use biospecimens in the biobank. An accreditation process can also be introduced for biobanks to harmonize collections and encourage use of biospecimens in the biobanks. KBN is preparing an on-line application system for the distribution of biospecimens and a biobank accreditation program and is trying to harmonize the biobanks.

Ureteral polypoid endometriosis causing hydroureteronephrosis

( Ok Ji Hoon ),( Cha Moon Seok ),( Han Myoung Seok ),( Cho Yeon Jean ),( Kang Ji Young ),( Bae Jong Woon ) 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.98 No.-

A 42-year-old nulliparous woman visited our hospital due to the left hydronephrosis which had been found during her regular check-up. Abdominal ultrasonography revealed the left hydroureteronephrosis and about 6-cm intramural uterine fibroid locating at the left lateral wall. She had mild dysmenorrhea during her periods but did not need to take a pill. Her pelvic examination revealed no evidence of the pelvic endometriosis. She underwent the laparoscopic surgery to remove the fibroid and find the reason of the hydronephrosis. The uterine fibroid had no relationship with the left hydronephrosis, but there was an adhesive peritoneal endometriotic lesion at the left pelvic brim. After dissection of the left retroperitoneal space, we found the swollen portion of the ureter beneath the adhesive peritoneum, which length was about 3cm. We performed the segmental resection of the swollen ureter and the ureteroureterostomy, After procedure, the resected specimen showed a 3-cm polypoid mass inside the lumen. Histologically, the mass was ureteral endometriosis. The postoperative course was uneventful. Ureteral polypoid endometriosis causing hydroureteronephrosis is rare. Hence, we report this case.

Genetic Analysis of Ancient Bones of Cervidae Animals from Archaeological Site in Jeju, Korea

Kang, Min-Chul,Han, Sang-Hyun,Jung, Yong-Hwan,Oh, Ju-Hyung,Kim, Gi-Ok,Ko, Jae-Woen,Oh, Moon-You The Korean Society for Integrative Biology 2007 Integrative biosciences Vol.11 No.2

DNA extracted from ancient bones of Cervidae animals was examined to identify the species and to determine the phylogenetic relationships to those from extant cervids. Abundant ancient bones were excavated from Kumsung archaeological site in Jeju Island, Korea, and were identified as Cervidae animals based on morphological features of their antlers and lower mandibles. Their mitochondrial DNA (mtDNA) control region (CR) was partially sequenced and subsequently compared with those previously reported in database. The results confirmed that the ancient sequences are lineage of Cervidae. On the phylogenetic trees constructed using the sequence diversity of the CR sequences of family Cervidae, the ancient DNA sequences were found on distinct clusters. The ancient sequences were located in the subfamily Capreolinae cluster, and six ancient sequences were closely related to those of extant Korean roe deer in Jeju Island and Korean Peninsula. Consequently, the results of this study suggest that the roe deer inhabited Jeju Island in ancient times. However, there is no evidence for the existence of subfamily Cervinae, including Sika deer, while it has been described in several historical records. The results suggest that this finding could contribute to understanding of the origin and phylogenetic relationships of extant and ancient roe deer on Jeju Island.

A Study on Electro-optical Characteristics of the UV Aligned FFS Cell on the Organic Layer

Han, Jeong-Min,Ok, Chul-Ho,Hwang, Jeoung-Yeon,Kim, Byoung-Yong,Kang, Dong-Hun,Kim, Jong-Hwan,Kim, Young-Hwan,Han, Jin-Woo,Lee, Sang-Keuk,Seo, Dae-Shik The Korean Institute of Electrical and Electronic 2007 Transactions on Electrical and Electronic Material Vol.8 No.3

In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the two kinds of ultraviolet (UV) alignment method on the organic thin film (polyimide: PI). The suitable organic layers for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the in-situ photoalignment method were studied; Disclination is observed after conventional photoalignment method for 1h, and in-situ photoalignment method for 1h. Monodomain alignment of the NLC can be observed via insitu photo alignment method for 2 h and 3 h. It is considered that NLC alignment is due to photo-depolymerization of the polymer with oblique non-polarized UV irradiation on PI surface. An unstable V-T curve of UV-aligned FFS-LCD with conventional photoalignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photoalignment method (1 h), and V-T curve of UV-aligned FFS-LCD with in-situ photo alignment method was much stable comparing with that of other UV-aligned FFSLCD's. As a result, more stable EO performance of UV-aligned FFS-LCD with in-situ photoalignment method for 3h is obtained than that of the other UV-aligned FFS-LCD's.

Increase of chondrogenic potentials in adipose-derived stromal cells by co-delivery of type I and type II TGFβ receptors encoding bicistronic vector system

Kang, Sun-Woong,Do, Hyun-Jin,Han, In-Bo,Shin, Dong-Ah,Kim, Hyun Ok,Kim, Jae-Hwan,Lee, Soo-Hong Elsevier 2012 Journal of controlled release Vol.160 No.3

<P><B>Abstract</B></P><P>Stem cell therapy has been developing rapidly as a potential cure for repairing or regenerating the functions of diseased organs and tissues. Adipose-derived stromal cells (ASCs) are an attractive cell source for stem cell therapy because they can be isolated easily from fat tissue in significant numbers and exhibit multiple differentiation potential under appropriate <I>in vitro</I> culture conditions. However, ASCs derived from individual donors can show wide variations in differentiation potential. In addition, the regulatory mechanisms underlying stem cell differentiation remain unclear. Transforming growth factor β (TGFβ) is a well-known ASC chondrogenic differentiation factor that stimulates ASC signaling pathways by activating transmembrane type I and type II receptors. We hypothesized that the chondrogenic differentiation potential of ASCs is dependent upon the expression of TGFβ receptors and could be improved by the co-delivery of type I (TGFβRI) and type II (TGFβRII) TGFβ receptors. To prove this, heterogeneity within the chondrogenic potential of ASCs isolated from 10 donors was examined and their susceptibility to TGFβ during the process of chondrogenic differentiation investigated. In addition, the results showed that co-delivery of the TGFβRI and TGFβRII genes increased the expression of TGFβ receptor signaling in ASCs with low chondrogenic potential, resulting in increased chondrogenic differentiation. Monitoring and delivering TGFβRI and TGFβRII may, therefore, be a powerful tool for predicting the differentiation potential of stem cells and for enhancing their differentiation capacity prior to stem cell transplantation.</P> <P><B>Graphical abstract</B></P><P>We established an efficient prediction method and enhancement of chondrogenic potential through measuring the expression ratio of ALK1 and ALK5 signaling and by co-delivery TGFβ receptor genes prior to transplantation.<ce:figure id='f0005'></ce:figure></P>

국내 코로나19 판데믹 기간 발생한 입원을 요하는 소아청소년 지역사회폐렴의 원인과 위험 인자

Kang Hae Min,Song Seung Ha,Ahn Bin,Park Ji Young,Kang Hyunmi,Kwak Byung Ok,Kim Dong Hyun,Lee Joon Kee,Choi Soo-Han,Choi Jae Hong,Choi Eun Hwa,Yun Ki Wook 대한소아감염학회 2023 Pediatric Infection and Vaccine Vol.30 No.1

Purpose: This study aimed to identify the etiology and risk factors of community-acquired pneumonia (CAP) requiring hospitalization in Korean children during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Clinical information of children admitted with CAP to Seoul National University Children’s Hospital (SNUCH) between January 1, 2021, and February 28, 2022, was retrospectively collected and analyzed. In addition, the etiologic diagnosis and demographic data of children with CAP who were discharged at the other seven hospitals between January and February 2022 were collected. Pneumonia was diagnosed using strict criteria comprising clinical symptoms, physical examination findings, and chest radiographic findings. Results: Among 91 children hospitalized with CAP at SNUCH during the 14-month period, 68.4% were aged <5 years and 79.1% had underlying diseases. Among the 95 CAP cases, respiratory assistance was required in 70.5%, and the use of a ventilator was required in 20.0%. A total of five patients expired, all of whom were either immunocompromised or had underlying neurological diseases. Neurological diseases and immunosuppression were significantly correlated with respiratory assistance (P=0.003) and death (P=0.014). A total of 55% of the detected respiratory pathogens were viruses, the most common of which was rhinovirus at 35.9%. Among the 169 children hospitalized for CAP at the eight institutions, ≥1 respiratory virus was detected in 92.3%, among which respiratory syncytial virus (79.8%) was the most prevalent. Conclusions: Even during the COVID-19 pandemic, Korean children were hospitalized with CAP caused by seasonal respiratory viral pathogens. Although atypical and pyogenic bacteria were not detected, continuous clinical monitoring and further prospective studies should be conducted.

LC Aligning Capabilities of a Nematic Liquid Crystal on Homeotropic Polyimide Surface by New Ion-beam Irradiation

Ok, Chul-Ho,Kang, Dong-Hun,Lee, Kang-Min,Han, Jin-Woo,Kim, Byoung-Yong,Oh, Byeong-Yun,Kim, Young-Hwan,Hwang, Jeong-Yeon,Lee, Sang-Keuk,Han, Jeong-Min,Seo, Dae-Shik The Korean Institute of Electrical and Electronic 2007 Transactions on Electrical and Electronic Material Vol.8 No.6

The liquid crystal(LC) aligning capabilities of a nematic liquid crystal(NLC) on a homeotropic polyimide(PI) surface using a new ion-beam method were studied. Exposure ion-beam of $45^{\circ}$ incidence angle shows a good LC alignment of the NLC on the homeotropic PI surface. Also, on the homeotropic PI surface, the tilt angle of the NLC by exposure ion-beam of $45^{\circ}$ incidence angle had a tendency to decrease as increased ion-beam energy density. And, on the homeotropic PI surface, the alignment character of the NLC with respect to ion-beam energy was good at 1500 eV. And we achieved satisfactory result for EO character.

A multicenter study of anaplastic oligodendroglioma: the Korean Radiation Oncology Group Study 13-12.

Kang, Hyun-Cheol,Yu, Tosol,Lim, Do Hoon,Kim, Il Han,Chung, Woong-Ki,Suh, Chang-Ok,Choi, Byung Ock,Cho, Kwan Ho,Cho, Jae Ho,Kim, Jin Hee,Nam, Do-Hyun,Park, Chul-Kee,Hong, Yong-Kil,Kim, In Ah M. Nijhoff ; Kluwer Academic Publishers 2015 Journal of neuro-oncology Vol.125 No.1

<P>Although some existing evidence supports the addition of chemotherapy (CT) to radiation therapy (RT) for anaplastic oligodendroglioma treatment, controversy about both the criteria for suitable candidates and the optimal treatment schedule remains. We reviewed data from 376 newly diagnosed anaplastic oliogodendroglial tumor patients from nine Korean institutes were reviewed from 2000 to 2010. Total tumor removal was performed in 146 patients. More than 85??% of the entire patients received postoperative RT, and 59??% received CT. Approximately 50??% (n??=??189) received CT in addition to RT and 9??% (n??=??32) received CT only. A multivariate analysis revealed that younger age, frontal lobe location of the tumor, gross total removal, 1p/19q codeletion, and initial RT were associated with longer progression-free and overall survival rates. No difference was observed in outcomes from the treatment that included either temozolomide or PCV (procarbazine, lomustine, and vincristine) in addition to RT regardless of the 1p/19q deletion status. A clear improvement in progression-free and overall survival was observed for RT and combined CT/RT in compared with CT only. Postoperative RT appears to improve survival for entire group thus total removal and 1p/19q codeletion may not be sufficient criteria to omit RT as a treatment option. These results suggest that RT should continue to be offered as the standard treatment option for patients with anaplastic oligodendroglial tumors.</P>