检索结果-南通市图书馆

World Journal of Engineering and Technology 2016年第3期4卷 186-192页

作者： young-Hyu Choi Cheol-Min Kim Hwan-Seock jeong jeong-ho youn Department of Mechanical Engineering Changwon National University Changwon Republic of Korea Department of Mechanical Design Changwon National University Changwon Republic of Korea Turf Grass Science Institute Hanul Inc. Hapcheon-Gun Republic of Korea

In case of manufacturing hexahedral ABS (Acrylonitrile Butadiene Styrene) plastic components using a FDM (Fused Deposition Modeling)-based 3D printer, undesirable shape errors occur in the product due to heat shrinkage. This paper experimentally ob-served the influence of the bed temperature change on the deformed shape errors of a hexahedral specimen of 100 × 50 × 50 mm3 produced by using a 3D printer. During printing work, the head nozzle temperature was kept at 240?C and the head speed was set at 50 mm/s. The chamber was enclosed with a PC-plate. 3D printing was conducted at four different bed temperatures;50?C, 70?C, 90?C, and 110?C. After the produced specimens naturally cooled down to room temperature, their deformed shape errors were measured. As a result, the higher the bed temperature, the lower the deformed shape errors of the specimens were. however, if the bed temperature had exceeded 120?C, laminating adhesion became poor. That seems to occur because of the material phase change and can make 3D printing work very hard as a consequence. Results of this study can be helpful to set optimum bed temperature condition in FDM additive manufacturing.

关键词： FDM Additive Manufacturing 3D Printing Heat Shrinkage Shape Error ABS

A New Encryption Mechanism Supporting the Update of Encrypted Data for Secure and Efficient Collaboration in the Cloud Environment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2025年第1期142卷 813-834页

作者： Chanhyeong Cho Byeori Kim Haehyun Cho Taek-young youn Department of Cyber Security Dankook UniversityYongin16890Republic of Korea Department of Software Soongsil UniversitySeoul07027Republic of Korea

With the rise of remote collaboration,the demand for advanced storage and collaboration tools has rapidly ***,traditional collaboration tools primarily rely on access control,leaving data stored on cloud servers vulnerable due to insufficient *** paper introduces a novel mechanism that encrypts data in‘bundle’units,designed to meet the dual requirements of efficiency and security for frequently updated collaborative *** bundle includes updated information,allowing only the updated portions to be reencrypted when changes *** encryption method proposed in this paper addresses the inefficiencies of traditional encryption modes,such as Cipher Block Chaining(CBC)and Counter(CTR),which require decrypting and re-encrypting the entire dataset whenever updates *** proposed method leverages update-specific information embedded within data bundles and metadata that maps the relationship between these bundles and the plaintext *** utilizing this information,the method accurately identifies the modified portions and applies algorithms to selectively re-encrypt only those *** approach significantly enhances the efficiency of data updates while maintaining high performance,particularly in large-scale data *** validate this approach,we conducted experiments measuring execution time as both the size of the modified data and the total dataset size *** show that the proposed method significantly outperforms CBC and CTR modes in execution speed,with greater performance gains as data size ***,our security evaluation confirms that this method provides robust protection against both passive and active attacks.

关键词： Cloud collaboration mode of operation data update efficiency

Effect of Palladium Nanoparticles on Photocatalytic Characteristics of N doped Titania Catalyst

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2015年第6期31卷 664-669页

作者： Jong-ho Lee jeong-Il youn young-Jig Kim Han-Jun Oh Department of Chemistry Hanseo University School of Advanced Materials Engineering Sungkyunkwan University Department of Materials Science Hanseo University

To improve the photocatalytic efficiency of TiO2nanotubular catalyst,N doped and Pd decorated titania nanotubes was successfully synthesized via anodizing,hydrazine hydrate treatment and photoreduction of Pd *** small Pd nanoparticles were precipitated on TiO2nanotubes through photoreduction of Pd ions,and its distribution is relatively *** X-ray photoelectron spectrometry（XPS） result,the N 1s spectrum represents two peaks with binding energy at 399.7 and 400.7 eV,which suggests that the nitrogen elements doped by hydrazine hydrate treatment are located in interstitial sites of the TiO2crystalline *** N doped TiO2nanotubes with Pd particles,a high photocurrent was detected due to increase of interface charge carrier separation ***,N doped and Pd decorated TiO2nanotubes exhibited much higher dye destruction efficiency and rate constant due to the synergistic effect of the N dopant and the Pd deposition on TiO2nanotubes.

关键词： Pd nanoparticle Titania nanotube Anodizing Dye dec

Multifaceted neuroprotective effects of(-)-epigallocatechin-3-gallate(EGCG)in Alzheimer's disease:an overview of pre-clinical studies focused onβ-amyloid peptide

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2022年第3期11卷 483-493页

作者： Kumju youn Chi-Tang ho Mira Jun Department of Food Science and Nutrition Dong-A UniversityBusan 49315Korea Department of Food Science Rutgers UniversityNJ 08901USA Department of Health Sciences The graduate School of Dong-A UniversityBusan 49315Korea

Alzheimer’s disease(AD)is the most common neurodegenerative disease characterized by cognitive decline and memory *** lines of evidence indicate that excessiveβ-amyloid peptide(Aβ)generation and aggregation play pivotal roles in the initiation of AD,leading to various biochemical alteration including oxidative damage,mitochondrial dysfunction,neuroinflammation,signaling pathway and finally resulting in neuronal *** has a complex pathogenic mechanism,and a single-target approach for anti-AD strategy is thus full of *** overcome these limitations,the present study focused to review on one of multiple target-compounds,(-)-epigallocatechin-3-gallate(EGCG)for the prevention and treatment of *** is a main bioactive polyphenol in green tea and has been reported to exert potent neuroprotective properties in a wide array of both cellular and animal models in *** review demonstrated multiple neuroprotective efficacies of EGCG by focusing on the involvement of Aβ-evoked damage and its Aβ***,to understand its mechanism of action on the brain,the permeability of the blood-brain barrier was also discussed.

关键词： Alzheimer’s disease β-Amyloid peptide Green tea EGCG Neuroinflammation

Effects of torrefied wood chip and vermicompost application on vegetation growth and nutrient uptake in the Saemangeum reclaimed land

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2020年第1期9卷 74-82页

作者： Aung Aung jeong Min Seo Si ho Han Ji young An Huong Thi Thuy Dao Woo Bin youn Byung Bae Park Department of Environment and Forest Resources College of Agriculture and Life SciencesChungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea Environmental Conservation Department Ministry of Natural Resources and Environmental ConservationNaypyitaw 15011Myanmar Institute of Agricultural Science College of Agriculture and Life SciencesChungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea.

Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water *** and control of understory vegetation that competes with seedlings may be of help in ameliorating soil physical and chemical properties,resulting in better seedling growth and reclamation ***,the amount of nutrients understory vegetation absorbs in this ecological process has been rarely ***,we aimed to investigate the effect of soil amendment on biomass production and nutrient uptake by weeds in the nutrient-poor reclaimed *** applied three levels of torrefied wood chip(TWC;0,2.5,and 5 Mg ha^(−1))and two levels of vermicompost(VC;0 and 2.7 Mg ha^(−1))as soil physical improvements and organic soil amendments in reclaimed land in the Republic of Korea,with Populus euramericana used as the crop ***:TWC did not influence weed biomass,but 2.7 Mg ha^(−1) VC significantly increased weed biomass by 21%compared to 0 Mg ha^(−1) VC ***(N),phosphorus(P),potassium(K),calcium(Ca),magnesium(Mg),and sodium(Na)concentrations in weeds were the highest in control,but there was no statistical difference among ***,VC treatment did marginally increase nutrient uptake in weeds,especially P,K,Ca,and *** treatments influenced crop tree ***:We conclude that VC can be used as an organic source of nutrients in reclaimed soil and that weed management is necessary to increase treatment effects on crop trees in this salt-affected reclaimed land.

关键词： Nutrient content Populus euramericana Saemangeum Soil amendment Weed biomass

Urgent ERCP for acute cholangitis reduces mortality and hospital stay in elderly and very elderly patients

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2016年第6期15卷 619-625页

作者： Chan Sun Park Hee Seok jeong Ki Bae Kim Joung-ho Han Hee Bok Chae Sei Jin youn Seon Mee Park Department of Internal Medicine Chungbuk National University College of Medicine

BACKGROUND： Acute cholangitis in old people is a cause of mortality and prolonged hospital stay. We evaluated the effects of methods and timing of biliary drainage on the outcomes of acute cholangitis in elderly and very elderly patients. METhoDS： We analyzed 331 patients who were older than 75 years and were diagnosed with acute calculous cholangitis. They were admitted to our hospital from 2009 to 2014. Patients＇ demographics, severity grading, methods and timing of biliary drainage, mortality, and hospital stay were retrospectively obtained from medical records. Clinical parameters and outcomes were compared between elderly （75-80 years, n= 156） and very elderly （≥81 years, n=175） patients. We analyzed the effects of methods [none, endoscopic retrograde cholangio- pancreatography （ERCP）, percutaneous transhepatic biliary drainage, or failure] and timing （urgent or early） of biliary drainage on mortality and hospital stay in these patients. RESULTS： Acute cholangitis in older patients manifested as atypical symptoms characterized as infrequent Charcot＇s triad （4.2%） and comorbidity in one-third of the patients. Patients were graded as mild, moderate, and severe cholangitis in 104 （31.4%）, 175 （52.9%）, and 52 （15.7%）, respectively. Urgent bili-ary drainage （≤24 hours） was performed for 80.5% （247/307） of patients. Very elderly patients tended to have more severe grades and were treated with sequential procedures of transient hiliary drainage and stone removal at different sessions. hospital stay was related to methods and timing of biliary drainage. Mortality was very low （1.5%） and not related to patient age but rather to the success or failure of biliary drainage and severity grading of the acute cholangitis. CONCLUSIONS： The methods and timing used for biliary drainage and severity of cholangitis are the major determinants of mortality and hospital stay in elderly and very elderly patients with acute cholangitis. Urgent successful ERCP is mandatory for favorable

关键词： acute cholangitis biliary drainage prognosis elderly very elderly

Anticancer effects of oligomeric proanthocyanidins on human colorectal cancer cell line, SNU-C4

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2005年第30期11卷 4674-4678页

作者： youn-Jung Kim Hae-jeong Park Seo-Hyun Yoon Mi-Ja Kim Kang-Hyun Leem Joo-ho Chung Hye-Kyung Kim Department of Dental Hygiene Department of Pharmacology Department of Obesity Management College of Oriental Medicine Department of Food and Biotechnology

AIM: Oligomeric proanthocyanidins (OPC), natural polyphenolic compounds found in plants, are known to have antioxidant and anti-cancer effects. We investigated whether the anti-cancer effects of the OPC are induced by apoptosis on human colorectal cancer cell line, ***: Colorectal cancer cell line, SNU-C4 was cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum. The cytotoxic effect of OPC was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylt-etrazolium bromide (MTT) assay. To find out the apoptotic cell death, 4, 6-diamidino-2-phenylindole (DAPI) staining,terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, reverse transcriptionpolymerase chain reaction (RT-PCR), and caspase-3 enzyme assay were ***: In this study, cytotoxic effect of OPC on SNUC4 cells appeared in a dose-dependent manner. OPC treatment (100 μg/mL) revealed typical morphological apoptotic features. Additionally OPC treatment (100 μg/mL)increased level of BAX and CASPASE-3, and decreased level of BCL-2 mRNA expression. Caspase-3 enzyme activity was also significantly increased by treatment of OPC (100 μg/mL) compared with ***: These data indicate that OPC caused cell death by apoptosis through caspase pathways on human colorectal cancer cell line, SNU-C4.

关键词： Oligomeric pranthocyanidins Apoptosis Anticancer effects Colorectal cancer

One-step method to enhance biotribological properties and biocompatibility of DLC coating by ion beam irradiation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2022年第7期10卷 1114-1126页

作者： Yuzhen LIU Kelun ZHANG Jae-ho HAN youn-hoo HWANG Shusheng XU Dae-Eun KIM Department of Mechanical Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Dermatology and Cutaneous Biology Research Institute Yonsei University College of MedicineSeoul 03722Republic of Korea State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

A one-step method was developed to create a highly biocompatible micropatterned surface on a diamond-like carbon(DLC)through irradiation with a nitrogen ion beam and thus enhance the biocompatibility of osseointegrated surfaces and biotribological performance of articular *** biocompatibility and biotribological mechanisms were analyzed in terms of the structure and morphology of *** was demonstrated that a layer enriched in sp^(3) C-N bonds was formed on the surface of the DLC after nitrogen ion beam ***,with an increase in the radiation dose,the content of sp^(3) C-N on the DLC surface increased significantly,and the biocompatibility was positively correlated with *** adhesion of the MC3T3 osteoblasts increased significantly from 32%to 86%under an irradiation dose of 8×10^(15) ions/cm^(2).In contrast,the micropattern had a significant negative effect on the adhesion of the osteoblasts as it physically hindered cell expansion and *** micropattern with a depth of 37 nm exhibited good friction properties,and the coefficient of friction was reduced by 21%at relatively high speeds.

关键词： ion beam irradiation biocompatibility diamond-like carbon(DLC) in-vivo micropattern biotribological performance

Glycyrrhizin attenuates HMGB1-induced hepatocyte apoptosis by inhibiting the p38-dependent mitochondrial pathway

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第7期18卷 679-684页

作者： Geum-youn Gwak Tae Gun Moon Dong ho Lee Byung Chul Yoo Department of Medicine Samsung Medical CenterSugnkyunkwan University School of Medicine50 Irwon-DongGangnam-Gu135-710 SeoulSouth Korea

AIM： To examine how High-mobility group box I （HMGB1） regulates hepatocyte apoptosis and, furthermore, to determine whether glycyrrhizin （GL）, a known HMGB1 inhibitor, prevents HMGBl-induced hepatocyte apoptosis.

关键词： High-mobility group box 1 Hepatocyte Apoptosis Glycyrrhizin p38 Mitochondria

Critical cooling rate on carbide precipitation during quenching of austenitic manganese steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2010年第2期7卷 178-182页

作者： youn-Soo Ham jeong-Tae Kim Si-young Kwak jeong-Kil Choi Woo-young Yoon Daeyang R-Tech.Co. Ltd290-28Daehwa-DongDaeduk-GuDaejeonKorea e-Design Center KITECH7-47Songdo-DongYeonsu-GuIncheon 406-800Korea Department of Materials Science and Engineering Korea UniversityAnam-DongSeongbuk-GuSeoul 136-701Korea

Critical cooling rate to avoid carbide precipitation during quenching of austenitic manganese steel was investigated by means of optical microscopy,image analyzer and numerical *** efficient heat treatment analysis program including temperature-dependent material properties was developed for the prediction of cooling rate and probability of carbide precipitation during quenching by finite difference ***-dependent heat transfer coefficient was adopted to achieve more precise *** ratio of carbide precipitation was measured by image analyzer to determine the critical point of carbide ***-dependent critical cooling rate at that point was calculated by the developed numerical ***,the probability of carbide precipitation on the whole area of specimen can be predicted by the proposed numerical program and the numerical result of a specimen was compared with the experimental result.

关键词： austenitic manganese steel carbide precipitation quenching critical cooling rate