800㎿급 발전소 복수기의 최적 운전점 및 운전방법에 대한 연구

장철호(Cheol-Ho Jang),홍은기(Eun-Kee Hong),황광원(Kwang-Won Hwang),윤린(Rin Yun) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5

Along with the recent construction of a 800㎿ thermal power plant it is necessary to check the soundness of the current operation of the condenser, and to investigate the effects of vacuum level of it on the turbine efficiency for the power plant. In this study, the performances of the condenser and the turbine for the 800㎿ thermal power plant were tested based on the ASME PTC 6 and ASME PTC 12.2 with the variation of the vacuum level. When the condenser vacuum levels were 719.91 ㎜Hg, 724.5 ㎜Hg, and 729.6 ㎜Hg, the turbine efficiencies were 47.36%, 47.47%, and 47.55%, respectively. From the regression analysis of the present data, it was estimated that the optimal vacuum point is between 729 ㎜Hg and 731 ㎜Hg. When this optimal point is to be applied to the condenser, the profit of 5.5 billion won/year is expected based on the '09 caloric cost.

Serum vitamin D3 levels are not associated with thyroid cancer prevalence in euthyroid subjects without autoimmune thyroid disease

( Yun Mi Choi ),( Won Gu Kim ),( Tae Yong Kim ),( Sung Jin Bae ),( Hong-kyu Kim ),( Eun Kyung Jang ),( Min Ji Jeon ),( Ji Min Han ),( Young Kee Shong ),( Won Bae Kim ) 대한내과학회 2017 The Korean Journal of Internal Medicine Vol.32 No.1

Background/Aims: Previous studies have suggested that elevated serum vitamin D levels might protect against thyroid cancer. Elevated serum thyroid stimulating hormone levels and autoimmune thyroid disease (AITD) are suggested to be thyroid cancer promoting factors but have not been well controlled in previous studies. We designed the present study to evaluate whether serum vitamin D levels are associated with thyroid cancer in euthyroid patients with no clinical evidence of AITD. Methods: This cross-sectional study included subjects who underwent routine health check-ups, including serum 25-hydroxy vitamin D3 (25(OH)D3) levels, anti-thyroid peroxidase antibody (TPO-Ab), and thyroid ultrasonography (US). Inclusion criteria were euthyroid, negative TPO-Ab, and no evidence of AITD by US findings. Thyroid cancer diagnoses were based on fine needle aspiration cytology and/or postsurgical histopathological findings. Results: We enrolled 5,186 subjects (64% male, 37% female) in this study, including 53 patients (1%) with a diagnosis of thyroid cancer (33 males, 20 females). Mean 25(OH)D3 levels were similar between the thyroid cancer and control groups (p = 0.20). Subgroup analysis according to sex or seasonal variation also revealed no differences in 25(OH)D3 levels between the two groups. Based on the levels of 25(OH)D3, there was no significant difference in the prevalence of thyroid cancer; the prevalence was 0.71%, 0.94%, 1.40%, and 0.82% in the deficient, insufficient, sufficient, and excess groups, respectively (p = 0.64). Conclusions: The levels of serum 25(OH)D3 are not associated with thyroid cancer prevalence in euthyroid subjects with no clinical evidence of AITD.

Exosomal miR-181b-5p Downregulation in Ascites Serves as a Potential Diagnostic Biomarker for Gastric Cancer-associated Malignant Ascites

Yun, Jieun,Han, Sang-Bae,Kim, Hong Jun,Go, Se-il,Lee, Won Sup,Bae, Woo Kyun,Cho, Sang-Hee,Song, Eun-Kee,Lee, Ok-Jun,Kim, Hee Kyung,Yang, Yaewon,Kwon, Jihyun,Chae, Hee Bok,Lee, Ki Hyeong,Han, Hye Sook The Korean Gastric Cancer Association 2019 Journal of gastric cancer Vol.19 No.3

Purpose: Peritoneal carcinomatosis in gastric cancer (GC) patients results in extremely poor prognosis. Malignant ascites samples are the most appropriate biological material to use to evaluate biomarkers for peritoneal carcinomatosis. This study identified exosomal MicroRNAs (miRNAs) differently expressed between benign liver cirrhosis-associated ascites (LC-ascites) and malignant gastric cancer-associated ascites (GC-ascites), and validated their role as diagnostic biomarkers for GC-ascites. Materials and Methods: Total RNA was extracted from exosomes isolated from 165 ascites samples (73 LC-ascites and 92 GC-ascites). Initially, microarrays were used to screen the expression levels of 2,006 miRNAs in the discovery cohort (n=22). Subsequently, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) analyses were performed to validate the expression levels of selected exosomal miRNAs in the training (n=70) and validation (n=73) cohorts. Furthermore, carcinoembryonic antigen (CEA) levels were determined in ascites samples. Results: The miR-574-3p, miR-181b-5p, miR-4481, and miR-181d were significantly downregulated in the GC-ascites samples compared to the LC-ascites samples, and miR-181b-5p showed the best diagnostic performance for GC-ascites (area under the curve [AUC]=0.798 and 0.846 for the training and validation cohorts, respectively). The diagnostic performance of CEA for GC-ascites was improved by the combined analysis of miR-181b-5p and CEA (AUC=0.981 and 0.946 for the training and validation cohorts, respectively). Conclusions: We identified exosomal miRNAs capable of distinguishing between non-malignant and GC-ascites, showing that the combined use of miR-181b-5p and CEA could improve diagnosis.

Characteristics of Fe-Cr-Al Alloy Nanopowders Prepared by Electrical Wire Explosion Process under Liquid Media

Yun, Jung-Yeul,Lee, Hye-Moon,Choi, Si-Young,Yang, SangSun,Lee, Dong-Won,Kim, Young-Jin,Kim, Byoung-Kee The Japan Institute of Metals 2011 Materials transactions Vol.52 No.2

<P>Fe-Cr-Al alloy nanopowders were successfully prepared by electrical wire explosion method in ethyl alcohol media. The formation of Fe-Cr-Al alloy nanopowder was monitored by X-ray diffraction. The alloy powders have spherical shape and nanometer size. The alloy powders prepared by the electrical wire explosion method have main crystal structures of bcc Fe-Cr alloy. The geometric mean diameter and geometric standard deviation of an alloy powder formed from a wire with diameter of 0.1 mm were 10.2 nm and 1.62, respectively. However, the geometric mean diameter and geometric standard deviation of an alloy powder formed from a wire with diameter of 0.2 mm were 15.4 nm and 1.66, respectively. These values indicate that the particle size of the alloy powders prepared by the EWE method was increased with wire diameter. Fe, Cr, and Al components are uniformly dispersed inside the powder.</P>

Autism Spectrum Disorder Diagnosis in Diagnostic and Statistical Manual of Mental Disorders-5 Compared to Diagnostic and Statistical Manual of Mental Disorders-IV

Yun Shin Lim,Kee Jeong Park,Hyo-Won Kim 대한소아청소년정신의학회 2018 소아청소년정신의학 Vol.29 No.4

Objectives: The objective of this study was to investigate the concordance of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV and DSM-5) diagnostic criteria for autism spectrum disorder (ASD). Methods: We retrospectively reviewed the medical records of 170 subjects (age range: 3–23, 140 boys) with developmental delay or social deficit from January 2011 to July 2016 at the Department of Psychiatry of Asan Medical Center. The Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS), and intelligence tests were performed for each subject. Diagnosis was reviewed and confirmed for each subject with DSM-IV Pervasive Developmental Disorder (PDD) and DSM-5 ASD criteria, respectively. Results: Fifty-eight of 145 subjects (34.1%) who were previously diagnosed as having PDD in DSM-IV did not meet DSM-5 ASD criteria. Among them, 28 (48.3%) had Asperger’s disorder based on DSM-IV. Most algorithm scores on ADOS and all algorithm scores on ADI-R were highest in subjects who met both DSM-IV PDD criteria and DSM-5 ASD criteria (the Convergent group), followed by subjects with a DSM-IV PDD diagnosis who did not have a DSM-5 ASD diagnosis (the Divergent group), and subjects who did not meet either DSM-IV PDD or DSM-5 ASD criteria (the non-PDD group). Intelligence quotient was lower in the Convergent group than in the Divergent group. Conclusion: The results of our study suggest that ASD prevalence estimates could be lower under DSM-5 than DSM-IV diagnostic criteria. Further prospective study on the impact of new DSM-5 ASD diagnoses in Koreans with ASD is needed.

Delayed Diagnosis of Probable Radiation Induced Spinal Cord Vascular Disorders

Won, Young Il,Kim, Chi Heon,Chung, Chun Kee,Yun, Tae Jin The Korean Neurosurgical Society 2015 Journal of Korean neurosurgical society Vol.57 No.3

Occasionally, unexpected neurological deficits occur after lumbar spinal surgery. We report a case of monoparesis after lumbar decompressive surgery. A 63-year-old man, who had undergone decompression of L4-5 for spinal stenosis 4 days previously in the other hospital, visted the emergency department with progressive weakness in the left leg and hypoesthesia below sensory level T7 on the right side. He had been cured of lung cancer with chemotherapy and radiation therapy 10 years previously, but detailed information of radiotherapy was not available. Whole spine magnetic resonance (MR) imaging showed fatty marrow change from T1 to T8, most likely due to previous irradiation. The T2-weighted MR image showed a high-signal T4-5 spinal cord lesion surrounded by a low signal rim, and the T1-weighted MR image showed focal high signal intensity with focal enhancement. The radiological diagnosis was vascular disorders with suspicious bleeding. Surgical removal was refused by the patient. With rehabilitation, the patient could walk independently without assistance 2 months later. Considering radiation induced change at thoracic vertebrae, vascular disorders may be induced by irradiation. If the spinal cord was previously irradiated, radiation induced vascular disorders needs to be considered.

An Updated Nationwide Epidemiology of Primary Brain Tumors in Republic of Korea, 2013

( Yun-sik Dho ),( Kyu-won Jung ),( Johyun Ha ),( Youngbeom Seo ),( Chul-kee Park ),( Young-joo Won ),( Heon Yoo ) 대한뇌종양학회 대한신경종양학회 2017 Brain Tumor Research and Treatment Vol.5 No.1

Background This report aims to provide accurate nationwide epidemiologic data on primary brain and central nervous system (CNS) tumors in the Republic of Korea. We updated the data by analyzing primary brain and CNS tumors diagnosed in 2013 using the data from the national cancer incidence database. Methods Data on primary brain and CNS tumors diagnosed in 2013 were collected from the Korean Central Cancer Registry. Crude and age-standardized rates were calculated in terms of gender, age, and histological type. Results A total of 11,827 patients were diagnosed with primary brain and CNS tumors in 2013. Brain and CNS tumors occurred in females more often than in males (female:male, 1.70:1). The most common tumor was meningioma (37.3%). Pituitary tumors (18.0%), gliomas (12.7%), and nerve sheath tumors (12.3%) followed in incidence. Glioblastomas accounted for 41.8% of all gliomas. In children (<19 years), sellar region tumors (pituitary and craniopharyngioma), embryonal/primitive/medulloblastoma, and germ cell tumors were the most common tumors. Conclusion This study should provide valuable information regarding the primary brain tumor epidemiology in Republic of Korea

Association between thyroid autoimmunity and Helicobacter pylori infection

( Yun Mi Choi ),( Tae Yong Kim ),( Eui Young Kim ),( Eun Kyung Jang ),( Min Ji Jeon ),( Won Gu Kim ),( Young Kee Shong ),( Won Bae Kim ) 대한내과학회 2017 The Korean Journal of Internal Medicine Vol.32 No.2

Background/Aims: There have been controversial reports linking Helicobacter pylori infection to autoimmune thyroid disease (AITD). However, data regarding the relationship are limited for Asian populations, which have an extremely high prevalence of H. pylori infection. We performed this study to investigate the association between H. pylori infection and AITD in Koreans. Methods: This study involved adults aged 30 to 70 years who had visited a health promotion center. A total of 5,502 subjects were analysed. Thyroid status was assessed by free thyroxine, thyroid stimulating hormone, and anti-thyroid peroxidase antibody (TPO-Ab). Immunoglobulin G (IgG) antibodies to H. pylori were measured as an indication of H. pylori infection. We compared the prevalence of TPO-Ab in subjects with and without H. pylori infection. Results: H. pylori IgG antibodies were found in 2,875 subjects (52.3%), and TPO-Ab were found in 430 (7.8%). Individuals positive for H. pylori Ab were older than those negative for H. pylori Ab (p < 0.01). The proportion of females was significantly higher in the TPO-Ab positive group (41.0% vs. 64.2%, p < 0.01). Prevalence of TPO-Ab positivity was higher in subjects with H. pylori infection (8.6% vs. 7.00%, p = 0.03), and this association was significant after adjusting for age, sex, and body mass index (odds ratio, 1.02; 95% confidence interval, 1.00 to 1.03; p = 0.04). Conclusions: In our study, prevalence of TPO-Ab positivity is more frequent in subjects with H. pylori infection. Our findings suggest H. pylori infection may play a role in the development of autoimmune thyroiditis.

Relationship-Based Cooperative work of a Multi-Robot System

Kee-Hyun Shin,Hyun-Kyoo Kang,Ji-Won Lee,Yun-Shick Eum,Mun-Hoi Kim,Tae-Young Lee,Sang-Yoon Lee 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

In this paper, we propose a novel paradigm to regulate the cooperation of a multiple mobile robot system. It defines relationships between robots in a similar way that relationships between humans are characterized in our societies. The degree of relationships can be changed over time. For example, it can be increased by the number of cooperation between robots. The robots autonomously determine whom to help based on their relationship. In this work, it is used particularly for regulating the cooperation of robots in an effective way. The overall performance of the proposed paradigm was tested by several experiments using a multi-robot system. The system was assigned to complete a task, which is clearing boxes in a pre-defined area. A couple of other models of cooperation without considering relationship were implemented. It was found that the execution time was reduced by 12 % with the proposed model compared with those of non-relational cooperation model.

Enhancement of continuous bubbles by non-thermal plasma for water treatment

Jae Won Lee,Yun Young Ji,Dong Kee Sohn,고한서 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

Non-thermal plasma is generated by excitation of the electron in gas or liquid medium. This technique has been applied to many industrial fields, especially for water treatment, because of the byproducts generated electrochemically by high-voltage discharge. Simultaneous production of plasma and bubbles is one of the methods to efficiently reduce the required energy for water treatment. The flow rate of injected gas and supplied electric energy are important parameters. In this study, the characteristics of the continuously generated bubbles with non-thermal plasma discahrge were investigated by experiment. The behavior of bubbles with and without discharge was analyzed by image processing. To verify the water treatment yield of bubbles with plasma generating byproducts, the decomposition of organic dye was investigated and analyzed. Due to the reduction of the surface tension of the interface, the volume of bubble with discharge showed shorter departure time with smaller volume. Bubbles with plasma discharge have faster bubble rising velocity, due to more spherical shape, which lowers the possibility of coalescence between bubbles, and is more effective for water treatment. The higher coalescence probability caused by increased Reynolds number resulted in the reduction of water treatment yield.