Effects of Pilger Rolling and Heat Treatment on Microstructure and Corrosion Resistance of Ag-electroplated 304 Stainless Steel Tubes

Hyun Park,Woo‑Jin Lee,Jae‑Han Son,Han‑Kyun Shin,Sung‑Kyu Hong,Hyo‑Jong Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

We introduce a cost-effective method that combines electroplating with metal cold working processes to manufacture compositetubes with robust corrosion resistance. First, a 3-step electroplating process was developed to form an adhesive anduniform Ag coating on the outer wall of a 304 stainless steel tube. The process consisted of a Ni-strike step for removing thepassivation layer of the initial 304 tube, Cu deposition for smoothing the surface by adding a buffer layer, and Ag deposition. To reinforce the interfacial adhesion between the electroplated layers and the 304 tube and increase the area of the Ag coating,a pilger rolling or pilger rolling + heat-treatment process was performed after the Ag electroplating process. Scanningelectron microscopy of the composite tubes after each process indicated that the as-deposited Ag coating changed fromhaving a rough to smooth surface after only pilger rolling and with additional heat treatment. Electron backscatter diffractionanalysis of the microstructures and textures of the tubes revealed that dynamic recrystallization occurred extensively duringpilger rolling, resulting in the formation of a relatively defect-free grain structure without heat treatment. Furthermore,electrochemical polarization curves determined that the Ag-coated composite tubes are superior to the uncoated 304 tubein terms of corrosion resistance under Cl−atmosphere, owing to the formation of a AgCl passivation layer during testing. Surface analysis of the composite tubes suggests that the properties of the AgCl passivation layer are related to the grainsize of the Ag coating and the density of plastic-deformation-induced defects.

Estimating Leaf Area Index of Paddy Rice from RapidEye Imagery to Assess Evapotranspiration in Korean Paddy Fields

Sang?Il Na,Suk Young Hong,Yi?Hyun Kim,Kyoung?Do Lee,So?Young Jang 한국토양비료학회 2013 한국토양비료학회지 Vol.46 No.4

Leaf area index (LAI) is important in explaining the ability of crops to intercept solar energy for biomass production, amount of plant transpiration, and in understanding the impact of crop management practices on crop growth. This paper describes a procedure for estimating LAI as a function of image?derived vegetation indices from temporal series of RapidEye imagery obtained from 2010 to 2012 using empirical models in a rice plain in Seosan, Chungcheongnam?do. Rice plants were sampled every two weeks to investigate LAI, fresh and dry biomass from late May to early October. RapidEye images were taken from June to September every year and corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). Linear, exponential, and expolinear models were developed to relate temporal satellite NDVIs to measured LAI. The expolinear model provided more accurate results to predict LAI than linear or exponential models based on root mean square error. The LAI distribution was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when RapidEye imagery was applied to expolinear model. The spatial trend of LAI corresponded with the variation in the vegetation growth condition.

Floristic characteristics of vascular plants and first distributional report of Pseudostellaria baekdusanensis M. Kim in Yongneup wetland protected area

Young-Chul Kim,Hyun-Hee Chae,Sang-Heock Oh,Seung-Ho Choi2,Moon-Pyo Hong3,Gi-Heum Nam,Jae-Yoon Choi,Hyun-Sook Choi,Kyu-Song Lee 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2

Yongneup wetland protected area, the only high moor in Korea, is a core area to conserve biodiversity. Even though the Yongneup wetland protected area is relatively small, various plant species are distributed in the Yongneup wetland protected area because it includes various habitats showing different environmental gradients. Vascular plants distributed in the Yongneup wetland protected area were identified as a total of 376 taxa that is composed of 73 families, 217 genera, 322 species, 3 subspecies, 44 varieties and 7 forms. For endangered plants designated by the Ministry of Environment, 5 species including Trientalis europaea var. arctica, Lilium dauricum, Halenia corniculata, Lychnis wilfordii and Menyanthes trifoliata were found and 34 taxa were confirmed to be distributed only in the mountainous wetland habitats. Regarding naturalized plants, a total of 11 taxa were distributed, but most of them were distributed in the areas where artificial interference has occurred. And in areas inside the wetlands that are relatively well preserved, 2 species of Bidens frondosa and Erigeron annuus were observed. In this study, the occurrence and distribution of Pseudostellaria baekdusanensis M. Kim, which was recently found in Mt. Baekdu and reported as a new species, were identified in the Yongneup wetland protected area. A wetland is a very vulnerable area to drastic environmental changes and damages to its ecosystem could cause the extinction of rare plant species which are distributed only in the wetlands. Therefore, it is mandatory that current status of the Yongneup wetland protected area is evaluated and actions to prevent rapid environmental changes are taken. Fourteen separate investigations were conducted in 2013 and another four in 2014, to evaluate current status of the Yongneup wetland protected area. These investigations have provided us the basic information for future actions of conservation and restoration.

Interaction of <i>Veratrum nigrum</i> with <i>Panax ginseng</i> against Obesity: A Sang-ban Relationship

Park, Jinbong,Jeon, Yong-Deok,Kim, Hye-Lin,Lim, Hara,Jung, Yunu,Youn, Dong-Hyun,Jeong, Mi-Young,Kim, Hyun-Ju,Kim, Sung-Hoon,Kim, Su-Jin,Hong, Seung-Heon,Um, Jae-Young Hindawi Publishing Corporation 2013 Evidence-based Complementary and Alternative Medic Vol.2013 No.-

<P>Obesity has become a major health threat in developed countries. However, current medications for obesity are limited because of their adverse effects. Interest in natural products for the treatment of obesity is thus rapidly growing. Korean Medicine (KM) is characterized by the wide use of herbal formulas. However, the combination rule of herbal formulas in KM lacks experimental evidence. According to <I>Shennong's Classic of Materia Medica</I>, the earliest book of herbal medicine, <I>Veratrum nigrum</I> (VN) has antagonistic features against <I>Panax ginseng</I> (PG), and the PG-VN pair is strictly forbidden. In this study, we have shown the effects of PG, VN, and their combination on obesity in high-fat (HF) diet-induced obese mice and in 3T3-L1 cells. PG, VN, and PG-VN combination significantly reduced weight gain and the fat pad weight in HF diet-induced obese mice. They also significantly decreased lipid accumulation and the expressions of two major adipogenesis factors, PPAR<I><I>γ</I></I> and C/EBP<I><I>α</I></I>, in 3T3-L1 cells. In addition, the PG-VN combination had synergistic effects compared with the mixture of extracts of PG and VN on inhibition of PPAR<I><I>γ</I></I> and C/EBP<I><I>α</I></I> expressions at lower doses. These results indicate a new potential anti-obese pharmacotherapy and also provide scientific evidence supporting the usage of herbal combinations instead of mixtures in KM.</P>

Surgery for Metachronous Liver Metastases from Stomach Cancer

( Sung Hyun Kim ),( Dai Hoon Han ),( Gi Hong Choi ),( Jin-sub Choi ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: The role of surgical therapy in patients with metachronous liver metastases from stomach cancer is still controversial. In this study, we evaluated surgical outcome of liver metastases in patients with stomach cancer by comparing chemotherapy. Methods: From January 1997 to December 2010, 180 medical records of the patients were retrospectively reviewed, who were diagnosed metachronous metastasis that was confined to liver after radical gas- trectomy for stomach cancer. Among them, multiple liver metastatic (> 3) patients and untreated patients were excluded. Consequently, 85 patients were enrolled. In the patients, overall survival (OS) was compared between patients who were performed liver resection and patients who were performed chemotherapy. Results: 42 patients were performed liver resection (Surgery group) and 43 patients were performed chemotherapy (Chemotherapy group). Disease free survival without liver metastasis was 14.9 months and 61 (71.8%) patients were revealed single liver metastasis. There were no significant differences in age, pathologic status of stomach cancer (e.g. location, size, stage, differentiation, lymphovascular invasion and perineural invasion) except tumor size (Surgery vs. Chemotherapy: 4.0±1.6cm vs. 5.2±2.7cm, p=0.013) There were also no significant differences in recurred tumor size and numbers. In survival analysis, the surgery group was superior in OS to the chemotherapy group. (Surgery vs. Chemotherapy: 29.1m (95%CI: 18.2-40.0) vs. 17.6m (95%CI: 13.9-21.3), p<0.001) Conclusions: Curative and also palliative surgery of metachronous liver metastases from stomach cancer may improve patients’ survival. Keywords: Stomach cancer, Liver metastases, Surgery, Outcome

Spontaneous Subcapsular Hematoma of the Kidney due to Acute Pyelonephritis (APN) : A Case Report

( Sang Hyun Park ),( Min Ok Kim ),( Hyun Jung Kim ),( Jun Hwa Hong ),( Dong Jin Kim ),( Sin Hyung Lim ),( Young Sook Lee ) 대한신장학회 2006 춘계학술대회 초록집 Vol.25 No.1

The Impact of Functional Electrical Stimulus and Proprioceptive Neuromuscular Facilitation to Scapula Adductor on Upper Limb Functions and Gait of the Patients with Stroke

Sang Hyun Moon,Wan Sung Hong,Sang Soo Kim,Ho Jung An,Young Hwa Song,Yong Kwon Kim,Jung Hyun Choi,Bo Kyoung Kim,Sung Ho Kim,Wan Suk Choi,Kyoung Ok Min 국제물리치료학회 2010 Journal of International Academy of Physical Ther Vol.1 No.2

The present study examined the effects of functional electrical stimulus( group 1), proprioceptive neuromuscular facilitation(group 2) and combined training of functional electrical stimulus and proprioceptive neuromuscular facilitation(group 3) with scapula adductor muscles on scapula movement, upper limb function and gait in fifteen subjects stroke patients. The training was thirty minutes a day, five times a week for six weeks, obtained result as follow, upper limb function was significant difference in the group 2(p<.05) but no significant difference in other groups. The change of weight bearing were significant difference in all the groups(p<.05), and increase of gait velocity were significant difference in all the group(p<.05). In conclusion, when applied with functional electrical stimulus, proprioceptive neuromuscular facilitation and combined training to the scapular adductor muscles, it was oberved in the course of the experiment that proprioceptive neuromuscular facilitation was the most effective treatment among the three methods applied to the scapula adductors.

Preparation of LiFe PO₄ Using Chitosan and its Cathodic Properties for Rechargeable Li-ion Batteries

Hong, Kyong-Soo,Yu, Seong-Mi,Ha, Myoung-Gyu,Ahn, Chang-Won,Hong, Tae-Eun,Jin, Jong-Sung,Kim, Hyun-Gyu,Jeong, Euh-Duck,Kim, Yang-Soo,Kim, Hae-Jin,Doh, Chil-Hoon,Yang, Ho-Soon,Jung, Hee Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.8

The LiFeP$O_4$ powder was synthesized by using the solid state reaction method with Fe($C_2O_4){\cdot}2H_2O,\;(NH_4)_2HPO_4,\;Li_2CO_3$, and chitosan as a carbon precursor material for a cathode of a lithium-ion battery. The chitosan added LiFePO4 powder was calcined at 350 ${^{\circ}C}$ for 5 hours and then 800 ${^{\circ}C}$ for 12 hours for the calcination. Then we calcined again at 800 ${^{\circ}C}$ for 12 hours. We characterized the synthesized compounds via the crystallinity, the valence states of iron ions, and their shapes using TGA, XRD, SEM, TEM, and XPS. We found that the synthesized powders were carbon-coated using TEM images and the iron ion is substituted from 3+ to 2+ through XPS measurements. We observed voltage characteristics and initial charge-discharge characteristics according to the C rate in LiFeP$O_4$ batteries. The obtained initial specific capacity of the chitosan added LiFeP$O_4$ powder is 110 mAh/g, which is much larger than that of LiFeP$O_4$ only powder.

High incidence of subsequent re-operation following treatments for medial meniscus tears combined with anterior cruciate ligament reconstruction: second-look arthroscopic study

( Sang-gyun Kim ),( Soo-hyun Kim ),( Jung-heum Baek ),( Jae-gyoon Kim ),( Ki-mo Jang ),( Hong-chul Lim ),( Ji-hoon Bae ) 대한슬관절학회 2019 대한슬관절학회지 Vol.31 No.1

Background: The Multicenter Orthopaedic Outcomes Network (MOON) group recently reported that medial meniscus (MM) repairs are associated with more frequent re-operations when compared to lateral meniscus (LM) repairs. The purpose of this study was to compare the meniscal healing and the incidence of subsequent reoperation of medial and lateral meniscal tears that occurred concurrently with anterior cruciate ligament (ACL) injuries. Methods: We retrospectively reviewed patients who underwent second-look arthroscopy after primary ACL reconstruction (ACLR) between June 2005 to December 2016. The healing of meniscal tears following repair or left in situ, and re-tear following partial meniscectomy, were evaluated via second-look arthroscopy and compared between medial and lateral meniscus. Moreover, the incidence of subsequent meniscal re-operation after the index ACLR were investigated and compared between medial and lateral meniscus. Subsequent meniscal re-operation was performed in cases of the following three symptomatic meniscus tears: re-tears at the meniscectomy site; new tears; and failed healing of repaired or left in situ meniscus. Results: There were 148 meniscal tears in 121 patients at index ACLR. There were 62 MM tears, 38 LM tears, and 24 bilateral meniscus tears. At second-look arthroscopy, the “successful healing” rate for tears following repair was higher in LM tears (91.2%) compared to MM tears (80.0%), although it was not statistically significant (p > 0.05). No significant differences were observed in the healing of left in situ tears or re-tear of meniscectomy site between medial and lateral meniscus. Patients with MM tears combined with ACL injuries had a higher incidence of subsequent meniscal re-operation compared to patients with LM tears (25.6% vs 16.1%, p = 0.025). Conclusions: There was a trend for the successful healing rate to be higher in LM repairs than MM repairs. Subsequent meniscal re-operations after ACLR were more frequent in patients with medial meniscal tears concurrently with ACL injuries in comparison to patients with lateral meniscal tears. Level of study: Level IV, retrospective case series.

Association of citalopram with congenital anomalies: A meta-analysis

( Hyun-hye Kang ),( Ki Hoon Ahn ),( Soon-cheol Hong ),( Bo Yong Kwon ),( Eun Hee Lee ),( Ji-sung Lee ),( Min-jeong Oh ),( Hai-joong Kim ) 대한산부인과학회 2017 Obstetrics & Gynecology Science Vol.60 No.2

Objective The antenatal use of citalopram, a widely prescribed selective serotonin reuptake inhibitor, has been suspected to be associated with congenital, particularly cardiac, anomalies. This study aimed to prove the association between citalopram use and congenital anomalies. Methods We searched the English literature from July 1998 to July 2015, by using the search terms `citalopram`, `pregnancy`, `birth defects`, `congenital anomalies`, and `malformations` in PubMed, Embase, Web of Science, and the Cochrane Library. Results Eight eligible articles were analyzed including a total of 1,507,896 participants. The odds ratio (OR) of major malformations associated with citalopram use during pregnancy was 1.07 (95% confidence interval [CI], 0.98 to 1.17). Concerning cardiac malformations, the OR for all included studies was 1.31 (95% CI, 0.88 to 1.93). The analysis of cardiac malformations was repeated to reduce heterogeneity after excluding one outlier study (OR, 1.03; 95% CI, 0.84 to 1.26). Conclusion From our data, it can be concluded that citalopram use is not associated with major birth defects. However, physicians should carefully weigh the benefits against the potential risks of citalopram use, and counsel patients accordingly.