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Die Casting Mold Design of the Thin-walled Aluminum Case by Computational Solidification Simulation

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Journal of Materials Science & Technology 2008年第3期24卷 383-388页

作者： Young-Chan Kim Chang-Seog Kang jae-ik cho Chang-Yeol Jeong Se-Weon choi Sung-Kil Hong Korea Institute of Industrial Technology chonnam National University

Recently, demand for the lightweight alloy in electric/electronic housings has been greatly increased. However, among the lightweight alloys, aluminum alloy thin-walled die casting is problematic because it is quite difficult to achieve sufficient fluidity and feedability to fill the thin cavity as the wall thickness becomes less than 1mm. Therefore, in this study, thin-walled die casting of aluminum （Al-Si-Cu alloy： ALDC 12） in size of notebook computer housing and thickness of 0.8 mm was investigated by solidification simulation （MAGMA soft） and actual casting experiment （Buhler Evolution B 53D）. Three different types of gating design, finger, tangential and split type with 6 vertical runners, were simulated and the results showed that sound thin-walled die casting was possible with tangential and split type gating design because those gates allowed aluminum melt to flow into the thin cavity uniformly and split type gating system was preferable gating design comparing to tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. Also, the solidification simulation agreed well with the actual die-casting and the casting showed no casting defects and distortion.

关键词： Aluminum casting alloy Thin-wall die casting Solidification simulation

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

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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

Three-Stage Transfer Learning with AlexNet50 for MRI Image Multi-Class Classification with Optimal Learning Rate

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 155-183页

作者： Suganya Athisayamani A.Robert Singh Gyanendra Prasad Joshi Woong cho School of Computing Sastra Deemed to be UniversityThanjavur613401India Department of Computational Intelligence SRM Institute of Science and TechnologyKattankulathur603203India Department of AI and Software Engineering Kangwon National UniversitySamcheok25913Republic of Korea Department of Electronics Information and Communication EngineeringKangwon National UniversitySamcheok25913Republic of Korea

In radiology,magnetic resonance imaging(MRI)is an essential diagnostic tool that provides detailed images of a patient’s anatomical and physiological *** is particularly effective for detecting soft tissue ***,radiologists manually interpret these images,which can be labor-intensive and time-consuming due to the vast amount of *** address this challenge,machine learning,and deep learning approaches can be utilized to improve the accuracy and efficiency of anomaly detection in MRI *** manuscript presents the use of the Deep AlexNet50 model for MRI classification with discriminative learning *** are three stages for learning;in the first stage,the whole dataset is used to learn the *** the second stage,some layers of AlexNet50 are frozen with an augmented dataset,and in the third stage,AlexNet50 with an augmented dataset with the augmented *** method used three publicly available MRI classification datasets:Harvard whole brain atlas(HWBA-dataset),the School of Biomedical Engineering of Southern Medical University(SMU-dataset),and The National Institute of Neuroscience and Hospitals brain MRI dataset(NINS-dataset)for *** hyperparameter optimizers like Adam,stochastic gradient descent(SGD),Root mean square propagation(RMS prop),Adamax,and AdamW have been used to compare the performance of the learning ***-dataset registers maximum classification *** evaluated the performance of the proposed classification model using several quantitative metrics,achieving an average accuracy of 98%.

关键词： MRI tumors classification AlexNet50 transfer learning hyperparameter tuning optimizer

Study on adhesively-bonded surface of tapered double cantilever specimen made of aluminum foam affected with shear force

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Journal of Central South University 2015年第12期22卷 4521-4527页

作者：孙洪鹏 cho jae-ung Division of Mechanical Engineering Graduate School Kongju National University Division of Mechanical and Automotive Engineering Kongju National University

Aluminum foam is widely used in diverse areas to minimize the weight and maximize the absorption of shock energy in lightweight structures and various *** presents a number of advantages,such as low density,incombustibility,non-rigidity,excellent energy absorptivity,sound absorptivity and low heat *** aluminum foam with an air cell structure was placed under the TDCB Mode II tensile load by using Landmark equipment manufactured by MTS to examine the shear failure *** angle of the tapered adhesively-bonded surfaces of specimens was designated as a variable,and three models were developed with the inclined angles differing from one another at 6°,8° and 10°.The specimens with the inclined angles of 6°,8° and 10° have the maximum reaction forces of 168 N,194 N when the forced displacements are 6,5 and 4.2 mm *** are three specimens with the inclined angles of 10°,8° and 6° in the order of maximum reaction *** the analysis result,the maximum equivalent stresses of 0.813 MPa and 0.895 MPa happened when the forced displacements of 6 mm and 5 mm proceeded at the models of 6° and 8°,respectively.A simulation was carried out on the basis of finite element method and the experimental *** results of the experiment and the simulation analysis are shown not different from each other ***,only a simulation could be confirmed to be performed in substitution of an experiment,which is costly and time-consuming in order to determine the shearing properties of materials made of aluminum foam with artificial data.

关键词： adhesive displacement force reaction shearing fracture characteristic tapered double cantilever beam(TDCB)

Scalable Ir-Doped NiFe₂O₄/TiO₂ Heterojunction Anode for Decentralized Saline Wastewater Treatment and H₂ Production

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NANO-MICRO LETTERS 2025年第1期17卷 1-18页

作者： Hong, Sukhwa Kim, Jiseon Park, jaebeom Im, Sunmi Hoffmann, Michael R. cho, Kangwoo Pohang Univ Sci & Technol POSTECH Div Environm Sci & Engn Pohang 790784 South Korea CALTECH Linde Labs Pasadena CA 91125 USA Yonsei Univ Int Campus Inst Convergence Res & Educ Adv Technol I CREATE Incheon 21983 South Korea

Wastewater electrolysis cells (WECs) for decentralized wastewater treatment/reuse coupled with H-2 production can reduce the carbon footprint associated with transportation of water, waste, and energy carrier. This study reports Ir-doped NiFe2O4 (NFI, similar to 5 at% Ir) spinel layer with TiO2 overlayer (NFI/TiO2), as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell. In dilute (0.1 M) NaCl solutions, the NFI/TiO2 marks superior activity and selectivity for chlorine evolution reaction, outperforming the benchmark IrO2. Robust operation in near-neutral pH was confirmed. Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO2 which serves both as the primary site for Cl- chemisorption and a protective layer for NFI as an ohmic contact. Galvanostatic electrolysis of NH4+-laden synthetic wastewater demonstrated that NFI/TiO2 not only achieves quasi-stoichiometric NH4+-to-N-2 conversion, but also enhances H-2 generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine. The scaled-up WEC with NFI/TiO2 was demonstrated for electrolysis of toilet wastewater.

关键词： Wastewater electrolysis cell Ir-doped NiFe2O4 Reactive chlorine species Decentralized H-2 production On-site wastewater treatment

Survival analysis based on human epidermal growth factor 2 status in stage Ⅱ-Ⅲ gastric cancer

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World Journal of Gastroenterology 2017年第41期23卷 7407-7414页

作者： Jang Ho cho jae Yun Lim jae Yong cho Division of Medical Oncology Department of Internal Medicine Gangnam Severance Hospital Yonsei University College of Medicine

AIM To investigate human epidermal growth factor 2(HER2) overexpression and validate its prognostic effect in stage Ⅱ-Ⅲ gastric *** We reviewed the data of patients who were diagnosed with gastric cancer between March 2008 and October 2013 at the Yonsei University Medical Center. Among these patients, 384 patients who met the inclusion criteria were analyzed retrospectively. RESULTS Thirty-two(8.3%) of the 384 stage Ⅱ-Ⅲ gastric cancer patients exhibited HER2 overexpression. The median follow-up duration was 26.0 mo. HER2-negative patients had superior recurrence-free survival(RFS) compared to HER2-positive patients(HR = 0.52, 95%CI: 0.30-0.89; P = 0.015). The median overall survival(OS) was significantly prolonged in the HER2-negative group compared with the HER2-positive group(55.0 mo vs 38.0 mo, HR = 0.43, 95%CI: 0.21-0.88, P = 0.021). OS was also prolonged in HER2-negative patients who received adjuvant chemotherapy compared to HER2-positive patients(55.0 vs 38.0mo, HR = 0.42, 95%CI: 0.18-1.00, P = 0.051). In patients who did not receive adjuvant chemotherapy,the median RFS was prolonged in the HER2-negative group compared to the HER2-positive group(not reached vs 12.0 mo, HR = 0.17, 95%CI: 0.06-0.49, P= 0.001). In a multivariate analysis, HER2 status(HR= 0.421, 95%CI: 0.206-0.861, P = 0.018) and Eastern Cooperative Oncology Group performance status(HR = 2.002, 95%CI: 1.530-2.618, P < 0.001) were independent predictors of *** Our findings showed that HER2-positive patients had inferior OS and RFS. Stage Ⅱ-Ⅲ HER2-positive patients might be potential candidates for targeted therapies involving trastuzumab.

关键词： Trastuzumab Gastric neoplasm Human epidermal growth factor 2

Site-Specific Zonation of Seismic Site Effects by Optimization of the Expert GIS-Based Geotechnical Information System for Western Coastal Urban Areas in South Korea

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International Journal of Disaster Risk Science 2019年第1期10卷 117-133页

作者： Han-Saem Kim Chang-Guk Sun Hyung-ik cho Earthquake Research Center Korea Institute of Geoscience and Mineral Resources Geological Research Division Korea Institute of Geoscience and Mineral Resources

Earthquake-induced disasters are often more severe over soft soils than over firm soils or rocks owing to the seismic site effects related to the amplification of ground motion. On a regional scale, such differences can be estimated by spatially predicting the subsurface soil thickness over the entire target area. Generally, soil deposits are deeper in coastal or riverside areas than in inland regions. In this study, the seismic site effects in the coastal metropolitan areas of Incheon and Bucheon, South Korea, were assessed to provide information on seismic hazards. Spatial prediction of geotechnical layers was performed for the entire study area within an advanced GIS framework. Approximately 7500 existing borehole records in the Incheon and Bucheon areas were gathered and archived into a GIS database. Surface geotechnical data were acquired from a walk-over survey. Based on the optimized geo-data, spatial zoning maps of site-specific seismic response parameters, based on multiscale geospatial modeling, were created and presented for use in a regional seismic mitigation strategy. Seismic zonation was also performed to determine site coefficients for seismic design over the entire target area and to compare them with each other. We verified that the geotechnical data based spatial zonation would be useful for seismic hazard mitigation.

关键词： Coastal urban areas Geodata Geostatistical spatial zonation Seismic site effects Site classification South Korea

Porous Microspheres Comprising CoSe2 Nanorods Coated with N-Doped Graphitic C and Polydopamine-Derived C as Anodes for Long-Lived Na-Ion Batteries

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Nano-Micro Letters 2022年第7期14卷 118-139页

作者： jae Seob Lee Rakesh Saroha Jung Sang cho Department of Engineering Chemistry Chungbuk National UniversityCheongjuChungbuk 361-763Republic of Korea

Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microspheres are introduced as anodes for excellent Na-ion batteries,particularly with long-lived cycle under carbonate-based electrolyte *** microspheres uniformly composed of ZIF-67 polyhedrons and polystyrene nanobeads(φ=40 nm)are synthesized using the facile spray pyrolysis technique,followed by the selenization process(P-CoSe_(2)@NGC NR).Further,the PDA-derived C-coated microspheres are obtained using a solution-based coating approach and the subsequent carbonization process(P-CoSe_(2)@PDA-C NR).The rational synthesis approach benefited from the synergistic effects of dual carbon coating,resulting in a highly conductive and porous nanostructure that could facilitate rapid diffusion of charge species along with efficient electrolyte infiltration and effectively channelize the volume ***,the prepared nanostructure exhibits extraordinary electrochemical performance,particularly the ultra-long cycle life *** instance,the advanced anode has a discharge capacity of 291(1000th cycle,average capacity decay of 0.017%)and 142 mAh g^(-1)(5000th cycle,average capacity decay of 0.011%)at a current density of 0.5 and 2.0 A g^(-1),respectively.

关键词： Spray pyrolysis Sodium-ion batteries Cobalt selenide nanorods Porous microspheres Dual carbon coating

High mobility group box 1 in the central nervous system:regeneration hidden beneath inflammation

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Neural Regeneration Research 2025年第1期20卷 107-115页

作者： Hanki Kim Bum Jun Kim Seungyon Koh Hyo Jin cho Xuelian Jin Byung Gon Kim Jun Young choi Department of Brain Science Ajou University School of MedicineSuwonSouth Korea Department of Biomedical Sciences Ajou University Graduate School of MedicineSuwonSouth Korea Department of Neurology Ajou University School of MedicineSuwonSouth Korea Department of Geriatrics The Affiliated Suqian First People’s Hospital of Nanjing Medical UniversitySuqianJiangsu ProvinceChina

High-mobility group box 1 was first discovered in the calf thymus as a DNA-binding nuclear protein and has been widely studied in diverse fields,including neurology and ***-mobility group box 1 in the extracellular space functions as a pro-inflammatory damage-associated molecular pattern,which has been proven to play an important role in a wide variety of central nervous system disorders such as ischemic stroke,Alzheimer’s disease,frontotemporal dementia,Parkinson’s disease,multiple sclerosis,epilepsy,and traumatic brain *** drugs that inhibit high-mobility group box 1 as a damage-associated molecular pattern,such as glycyrrhizin,ethyl pyruvate,and neutralizing anti-high-mobility group box 1 antibodies,are commonly used to target high-mobility group box 1 activity in central nervous system *** it is commonly known for its detrimental inflammatory effect,high-mobility group box 1 has also been shown to have beneficial pro-regenerative roles in central nervous system *** this narrative review,we provide a brief summary of the history of high-mobility group box 1 research and its characterization as a damage-associated molecular pattern,its downstream receptors,and intracellular signaling pathways,how high-mobility group box 1 exerts the repair-favoring roles in general and in the central nervous system,and clues on how to differentiate the pro-regenerative from the pro-inflammatory *** targeting high-mobility group box 1 in the central nervous system may benefit from differentiating between the two functions rather than overall suppression of high-mobility group box 1.

关键词： central nervous system damage-associated molecular pattern ethyl pyruvate glycyrhizzin high mobility group box 1 inflammation neural stem cells neurodevelopment oligodendrocyte progenitor cells redox status regeneration