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Secure Transmission of Compressed Medical Image Sequences on Communication Networks Using Motion Vector Watermarking
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作者 Rafi Ullah Mohd Hilmi bin Hasan +1 位作者 Sultan Daud Khan Mussadiq Abdul Rahim 《Computers, Materials & Continua》 SCIE EI 2024年第3期3283-3301,共19页
Medical imaging plays a key role within modern hospital management systems for diagnostic purposes.Compression methodologies are extensively employed to mitigate storage demands and enhance transmission speed,all whil... Medical imaging plays a key role within modern hospital management systems for diagnostic purposes.Compression methodologies are extensively employed to mitigate storage demands and enhance transmission speed,all while upholding image quality.Moreover,an increasing number of hospitals are embracing cloud computing for patient data storage,necessitating meticulous scrutiny of server security and privacy protocols.Nevertheless,considering the widespread availability of multimedia tools,the preservation of digital data integrity surpasses the significance of compression alone.In response to this concern,we propose a secure storage and transmission solution for compressed medical image sequences,such as ultrasound images,utilizing a motion vector watermarking scheme.The watermark is generated employing an error-correcting code known as Bose-Chaudhuri-Hocquenghem(BCH)and is subsequently embedded into the compressed sequence via block-based motion vectors.In the process of watermark embedding,motion vectors are selected based on their magnitude and phase angle.When embedding watermarks,no specific spatial area,such as a region of interest(ROI),is used in the images.The embedding of watermark bits is dependent on motion vectors.Although reversible watermarking allows the restoration of the original image sequences,we use the irreversible watermarking method.The reason for this is that the use of reversible watermarks may impede the claims of ownership and legal rights.The restoration of original data or images may call into question ownership or other legal claims.The peak signal-to-noise ratio(PSNR)and structural similarity index(SSIM)serve as metrics for evaluating the watermarked image quality.Across all images,the PSNR value exceeds 46 dB,and the SSIM value exceeds 0.92.Experimental results substantiate the efficacy of the proposed technique in preserving data integrity. 展开更多
关键词 Block matching algorithm(BMA) compression full-search algorithm motion vectors ultrasound image sequence WATERMARKING
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Simple bone cysts of the proximal humerus presented with limb length discrepancy:A case report
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作者 Cing Syue Lin Shang Ming Lin +2 位作者 Syang-Peng Rwei Chin-Wen Chen Tsung-Yu Lan 《World Journal of Clinical Cases》 SCIE 2024年第6期1130-1137,共8页
BACKGROUND Simple bone cysts(SBC)are benign tumor-like bone lesions typically identified in children.While SBC may lead to growth disturbances or growth arrest,such cases are uncommon.The mechanisms behind these obser... BACKGROUND Simple bone cysts(SBC)are benign tumor-like bone lesions typically identified in children.While SBC may lead to growth disturbances or growth arrest,such cases are uncommon.The mechanisms behind these observations remain unclear.Additionally,research on the etiology of SBC remains inconclusive,and there has been no consensus on the appropriate timing and methodology for treatment.CASE SUMMARY Here,we present our experience in the successful surgical management of a 10-year-old girl with SBC,who presented with a pathological fracture complicated by malunion of the displaced fracture,varus deformity,and limb length discrepancy.We hypothesized two possible etiologies for the patient’s growth arrest and subsequent humerus varus deformity:(1)Direct disruption of the physis by fluid from the cyst itself;and(2)damage to the epiphysis due to repetitive pathological fractures associated with SBC.In addressing this case,surgical intervention was undertaken to correct the proximal humerus varus deformity.This approach offered the advantages of simultaneously correcting angular abnormalities,achieving mild limb lengthening,providing definitive SBC treatment,and reducing the overall treatment duration.CONCLUSION As per current literature,acute correction of acute angular deformity in proximal humeral SBC is not well comprehended.However,in this specific case,acute correction was considered an optimal solution. 展开更多
关键词 Bone cyst Solitary cysts BENIGN HUMERUS Growth arrest Limb length discrepancy Case report
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Improving the Transmission Efficiency of a WSN with the IACO Algorithm
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作者 Wen-Tsai Sung Sung-Jung Hsiao 《Computer Systems Science & Engineering》 SCIE EI 2023年第10期1061-1076,共16页
The goal of this study is to reduce the energy consumption of the sensing network and enhance the overall life cycle of the network.This study proposes a data fusion algorithm for wireless sensor networks based on imp... The goal of this study is to reduce the energy consumption of the sensing network and enhance the overall life cycle of the network.This study proposes a data fusion algorithm for wireless sensor networks based on improved ant colony optimization(IACO)to reduce the amount of data transmitted by wireless sensor networks(WSN).This study updates pheromones for multiple optimal routes to improve the global optimal route in search function.The algorithm proposed in this study can reduce node energy consumption,improve network load balancing and prolong network life cycle.Through data fusion,regression analysis model and information processing of each node,this study uses an improved ant colony algorithm to identify the transferals avoid superfluous energy waste caused by long-span network transferal,set the shortest route and transmit data to the central node.The algorithm proposed in this study is conducive to improving the life cycle and stable network,that is,the most suitable and effective way to improve the energy consumption rate of the sensing nodes. 展开更多
关键词 IACO WSN transmission efficiency control strategy regression analysis
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Investigation of the sodium storage mechanism of iron fluoride hydrate cathodes using X-ray absorption spectroscopy and mossbauer spectroscopy
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作者 Ghulam Ali Muhammad Akbar +4 位作者 Faiza Jan Iftikhar Qamar Wali Beata Kalska Szostko Dariusz Satuła Kyung Yoon Chung 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第2期535-542,I0014,共9页
Elucidation of a reaction mechanism is the most critical aspect for designing electrodes for highperformance secondary batteries.Herein,we investigate the sodium insertion/extraction into an iron fluoride hydrate(FeF_... Elucidation of a reaction mechanism is the most critical aspect for designing electrodes for highperformance secondary batteries.Herein,we investigate the sodium insertion/extraction into an iron fluoride hydrate(FeF_(3)·0.5H_(2)O)electrode for sodium-ion batteries(SIBs).The electrode material is prepared by employing an ionic liquid 1-butyl-3-methylimidazolium-tetrafluoroborate,which serves as a reaction medium and precursor for F^(-)ions.The crystal structure of FeF_(3)·0.5H_(2)O is observed as pyrochlore type with large open 3-D tunnels and a unit cell volume of 1129A^(3).The morphology of FeF_(3)·0.5H_(2)O is spherical shape with a mesoporous structure.The microstructure analysis reveals primary particle size of around 10 nm.The FeF_(3)·0.5H_(2)O cathode exhibits stable discharge capacities of 158,210,and 284 mA h g^(-1) in three different potential ranges of 1.5-4.5,1.2-4.5,and 1.0-4.5 V,respectively at 0.05 C rate.The specific capacities remained stable in over 50 cycles in all three potential ranges,while the rate capability was best in the potential range of 1.5-4.5 V.The electrochemical sodium storage mechanism is studied using X-ray absorption spectroscopy,indicating higher conversion at a more discharged state.Ex-situ M?ssbauer spectroscopy strengthens the results for reversible reduction/oxidation of Fe.These results will be favorable to establish high-performance cathode materials with selective voltage window for SIBs. 展开更多
关键词 Iron fluoride Sodium-ion batteries PYROCHLORE X-ray absorption spectroscopy Mössbauer spectroscopy
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Energy-Efficient Approaches for a Machine Tool Building in a University through Field Measurement and Energy Modelling
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作者 Kusnandar Win-Jet Luo +2 位作者 Indra Permana Fu-Jen Wang Gantulga Bayarkhuu 《Energy Engineering》 EI 2023年第6期1387-1399,共13页
The heating,ventilating,and air conditioning(HVAC)system consumes nearly 50%of the building’s energy,especially in Taiwan with a hot and humid climate.Due to the challenges in obtaining energy sources and the negativ... The heating,ventilating,and air conditioning(HVAC)system consumes nearly 50%of the building’s energy,especially in Taiwan with a hot and humid climate.Due to the challenges in obtaining energy sources and the negative impacts of excessive energy use on the environment,it is essential to employ an energy-efficient HVAC system.This study conducted the machine tools building in a university.The field measurement was carried out,and the data were used to conduct energymodelling with EnergyPlus(EP)in order to discover some improvements in energy-efficient design.The validation between fieldmeasurement and energymodelling was performed,and the error rate was less than 10%.The following strategies were proposed in this study based on several energy-efficient approaches,including room temperature settings,chilled water supply temperature settings,chiller coefficient of performance(COP),shading,and building location.Energy-efficient approaches have been evaluated and could reduce energy consumption annually.The results reveal that the proposed energy-efficient approaches of room temperature settings(3.8%),chilled water supply temperature settings(2.1%),chiller COP(5.9%),using shading(9.1%),and building location(3.0%),respectively,could reduce energy consumption.The analysis discovered that using a well-performing HVAC system and building shading were effective in lowering the amount of energy used,and the energy modelling method could be an effective and satisfactory tool in determining potential energy savings. 展开更多
关键词 ENERGY-EFFICIENT energy modelling field measurement BEMS machine tools building
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Identifying Brand Consistency by Product Differentiation Using CNN
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作者 Hung-Hsiang Wang Chih-Ping Chen 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期685-709,共25页
This paper presents a new method of using a convolutional neural network(CNN)in machine learning to identify brand consistency by product appearance variation.In Experiment 1,we collected fifty mouse devices from the ... This paper presents a new method of using a convolutional neural network(CNN)in machine learning to identify brand consistency by product appearance variation.In Experiment 1,we collected fifty mouse devices from the past thirty-five years from a renowned company to build a dataset consisting of product pictures with pre-defined design features of their appearance and functions.Results show that it is a challenge to distinguish periods for the subtle evolution of themouse devices with such traditionalmethods as time series analysis and principal component analysis(PCA).In Experiment 2,we applied deep learning to predict the extent to which the product appearance variation ofmouse devices of various brands.The investigation collected 6,042 images ofmouse devices and divided theminto the Early Stage and the Late Stage.Results show the highest accuracy of 81.4%with the CNNmodel,and the evaluation score of brand style consistency is 0.36,implying that the brand consistency score converted by the CNN accuracy rate is not always perfect in the real world.The relationship between product appearance variation,brand style consistency,and evaluation score is beneficial for predicting new product styles and future product style roadmaps.In addition,the CNN heat maps highlight the critical areas of design features of different styles,providing alternative clues related to the blurred boundary.The study provides insights into practical problems for designers,manufacturers,and marketers in product design.It not only contributes to the scientific understanding of design development,but also provides industry professionals with practical tools and methods to improve the design process and maintain brand consistency.Designers can use these techniques to find features that influence brand style.Then,capture these features as innovative design elements and maintain core brand values. 展开更多
关键词 Machine learning product differentiation brand consistency principal component analysis convolutional neural network computer mouse
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An Innovative Approach Using TKN-Cryptology for Identifying the Replay Assault
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作者 Syeda Wajiha Zahra Muhammad Nadeem +6 位作者 Ali Arshad Saman Riaz Muhammad Abu Bakr Ashit Kumar Dutta Zaid Alzaid Badr Almutairi Sultan Almotairi 《Computers, Materials & Continua》 SCIE EI 2024年第1期589-616,共28页
Various organizations store data online rather than on physical servers.As the number of user’s data stored in cloud servers increases,the attack rate to access data from cloud servers also increases.Different resear... Various organizations store data online rather than on physical servers.As the number of user’s data stored in cloud servers increases,the attack rate to access data from cloud servers also increases.Different researchers worked on different algorithms to protect cloud data from replay attacks.None of the papers used a technique that simultaneously detects a full-message and partial-message replay attack.This study presents the development of a TKN(Text,Key and Name)cryptographic algorithm aimed at protecting data from replay attacks.The program employs distinct ways to encrypt plain text[P],a user-defined Key[K],and a Secret Code[N].The novelty of the TKN cryptographic algorithm is that the bit value of each text is linked to another value with the help of the proposed algorithm,and the length of the cipher text obtained is twice the length of the original text.In the scenario that an attacker executes a replay attack on the cloud server,engages in cryptanalysis,or manipulates any data,it will result in automated modification of all associated values inside the backend.This mechanism has the benefit of enhancing the detectability of replay attacks.Nevertheless,the attacker cannot access data not included in any of the papers,regardless of how effective the attack strategy is.At the end of paper,the proposed algorithm’s novelty will be compared with different algorithms,and it will be discussed how far the proposed algorithm is better than all other algorithms. 展开更多
关键词 Replay attack MALWARE message attack file encryption CRYPTOLOGY data security
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Nodule Detection Using Local Binary Pattern Features to Enhance Diagnostic Decisions
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作者 Umar Rashid Arfan Jaffar +2 位作者 Muhammad Rashid Mohammed S.Alshuhri Sheeraz Akram 《Computers, Materials & Continua》 SCIE EI 2024年第3期3377-3390,共14页
Pulmonary nodules are small, round, or oval-shaped growths on the lungs. They can be benign (noncancerous) or malignant (cancerous). The size of a nodule can range from a few millimeters to a few centimeters in diamet... Pulmonary nodules are small, round, or oval-shaped growths on the lungs. They can be benign (noncancerous) or malignant (cancerous). The size of a nodule can range from a few millimeters to a few centimeters in diameter. Nodules may be found during a chest X-ray or other imaging test for an unrelated health problem. In the proposed methodology pulmonary nodules can be classified into three stages. Firstly, a 2D histogram thresholding technique is used to identify volume segmentation. An ant colony optimization algorithm is used to determine the optimal threshold value. Secondly, geometrical features such as lines, arcs, extended arcs, and ellipses are used to detect oval shapes. Thirdly, Histogram Oriented Surface Normal Vector (HOSNV) feature descriptors can be used to identify nodules of different sizes and shapes by using a scaled and rotation-invariant texture description. Smart nodule classification was performed with the XGBoost classifier. The results are tested and validated using the Lung Image Consortium Database (LICD). The proposed method has a sensitivity of 98.49% for nodules sized 3–30 mm. 展开更多
关键词 Pulmonary nodules SEGMENTATION HISTOGRAM THRESHOLDING
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GENERAL DECAY OF SOLUTIONS FOR A VISCOELASTIC EQUATION WITH NONLINEAR DAMPING AND SOURCE TERMS 被引量:12
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作者 Wu Shuntang 《Acta Mathematica Scientia》 SCIE CSCD 2011年第4期1436-1448,共13页
The initial boundary value problem for a viscoelastic equation | u t | ρ u tt △u-△u tt + t 0 g(ts)△u(s)ds + | u t | m u t = | u | p u in a bounded domain is considered, where ρ, m, p > 0 and g is a nonnegative... The initial boundary value problem for a viscoelastic equation | u t | ρ u tt △u-△u tt + t 0 g(ts)△u(s)ds + | u t | m u t = | u | p u in a bounded domain is considered, where ρ, m, p > 0 and g is a nonnegative and decaying function. The general uniform decay of solution energy is discussed under some conditions on the relaxation function g and the initial data by adopting the method of [14, 15, 19]. This work generalizes and improves earlier results in the literature. 展开更多
关键词 粘弹性方程 非线性阻尼 初始边界值问题 腐烂 源项 Pgt 衰减 函数
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Rotary ultrasonic-assisted milling of brittle materials 被引量:6
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作者 KUO Kei-lin TSAO Chung-chen 《中国有色金属学会会刊:英文版》 CSCD 2012年第S3期793-800,共8页
In order to improve the machining efficiency of ultrasonic milling,the easiest and most effective approach was started with the improvement of tool design.The main objective of this research was to utilize rotary ultr... In order to improve the machining efficiency of ultrasonic milling,the easiest and most effective approach was started with the improvement of tool design.The main objective of this research was to utilize rotary ultrasonic machining (RUM's) effectiveness in removing brittle materials to extend the applications of this independent,innovative manufacturing method (self-driving rotary ultrasonic machining),and to experimentally investigate its milling application on brittle materials.The designed tool was used in the conjunction with previously established RUM machine tools,and glass was selected as workpiece for experiments.The interrelationship between feed rate and depth of cut was discussed.By measuring the surface roughness of workpiece,the overall efficacy of utilizing RUM for milling was evaluated and presented.Ultrasonic assisted milling results in the reduction of milling resistance,which leads to a greater process rate. 展开更多
关键词 ROTARY ULTRASONIC ULTRASONIC ASSISTED MILLING BRITTLE material
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Dynamic strength of rock with single planar joint under various loading rates at various angles of loads applied 被引量:5
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作者 Pei-Yun Shu Hung-Hui Li +1 位作者 Tai-Tien Wang Tzuu-Hsing Ueng 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第3期545-554,共10页
Intact rock-like specimens and specimens that include a single, smooth planar joint at various angles are prepared for split Hopkinson pressure bar(SHPB) testing. A buffer pad between the striker bar and the incident ... Intact rock-like specimens and specimens that include a single, smooth planar joint at various angles are prepared for split Hopkinson pressure bar(SHPB) testing. A buffer pad between the striker bar and the incident bar of an SHPB apparatus is used to absorb some of the shock energy. This can generate loading rates of 20.2-4627.3 GPa/s, enabling dynamic peak stresses/strengths and associated failure patterns of the specimens to be investigated. The effects of the loading rate and angle of load applied on the dynamic peak stresses/strengths of the specimens are examined. Relevant experimental results demonstrate that the failure pattern of each specimen can be classified as four types: Type A, integrated with or without tiny flake-off; Type B, slide failure; Type C, fracture failure; and Type D, crushing failure. The dynamic peak stresses/strengths of the specimens that have similar failure patterns increase linearly with the loading rate, yielding high correlations that are evident on semi-logarithmic plots. The slope of the failure envelope is the smallest for slide failure, followed by crushing failure, and that of fracture failure is the largest. The magnitude of the plot slope of the dynamic peak stress against the loading rate for the specimens that are still integrated after testing is between that of slide failure and crushing failure. The angle of application has a limited effect on the dynamic peak stresses/strengths of the specimens regardless of the failure pattern, but it affects the bounds of the loading rates that yield each failure pattern, and thus influences the dynamic responses of the single jointed specimen. Slide failure occurs at the lowest loading rate of any failure, but can only occur in single jointed specimen that allows sliding.Crushing failure is typically associated with the largest loading rate, and fracture failure may occur when the loading rate is between the boundaries for slide failure and crushing failure. 展开更多
关键词 装载率 负担 岩石 关节 平面 动态力 评价 幻灯片
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Seismic performance of tunnel lining of side-by-side and vertically stacked twin-tunnels 被引量:3
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作者 陳水龍 魏敏樺 《Journal of Central South University》 SCIE EI CAS 2011年第4期1226-1234,共9页
The dynamic interaction between tunnel lining and its surrounding soil is a complicated issue as the magnitude of seismic wave from bedrock to the structure can be easily influenced by the geometrical layout and struc... The dynamic interaction between tunnel lining and its surrounding soil is a complicated issue as the magnitude of seismic wave from bedrock to the structure can be easily influenced by the geometrical layout and structural stiffness of the tunnel.A series of numerical analysis was conducted to study the dynamic response of the tunnel lining of side-by-side and vertically stacked double-tube tunnel since the inertia and kinematic interactions between the tunnel lining and the surrounding soil during an earthquake could induce excessive stresses to the lining itself due to the stiffness variation between the lining and the soil.Real earthquake ground acceleration was used as an input motion in the dynamic analysis.The interactive behavior of bending moment and axial forces,and the displacement of the tunnels were used to evaluate the effect of tunnel geometrical layout on the performance of the lining.It is found that the effect of earthquake on the axial thrust of the lining is insignificant,and there is a reduction of the bending moment in the lining due to the redistribution of the surrounding soil after the earthquake. 展开更多
关键词 隧道衬砌 抗震性能 堆叠 垂直 相互作用 结构刚度 几何布局 地震加速度
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GENERAL DECAY OF SOLUTIONS FOR A VISCOELASTIC EQUATION WITH BALAKRISHNAN-TAYLOR DAMPING AND NONLINEAR BOUNDARY DAMPING-SOURCE INTERACTIONS 被引量:2
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作者 吴舜堂 《Acta Mathematica Scientia》 SCIE CSCD 2015年第5期981-994,共14页
A viscoelastic equation with Balakrishnan-Taylor damping and nonlinear boundary/interior sources is considered in a bounded domain. Under appropriate assumptions imposed on the source and the damping, we establish uni... A viscoelastic equation with Balakrishnan-Taylor damping and nonlinear boundary/interior sources is considered in a bounded domain. Under appropriate assumptions imposed on the source and the damping, we establish uniform decay rate of the solution energy in terms of the behavior of the nonlinear feedback and the relaxation function, without setting any restrictive growth assumptions on the damping at the origin and weakening the usual assumptions on the relaxation function. 展开更多
关键词 粘弹性方程 非线性边界 能量衰减率 阻尼 相互作用 非线性反馈 行为功能 有界域
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BLOW-UP OF SOLUTION FOR A VISCOELASTIC WAVE EQUATION WITH DELAY 被引量:2
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作者 吴舜堂 《Acta Mathematica Scientia》 SCIE CSCD 2019年第1期329-338,共10页
In this paper, we consider the following viscoelastic wave equation with delay|u_t|~ρu_(tt)-△u-△u_(tt)+∫_0~t g(t-8)△u(8)d8 + μ_1 u_t(x,t) + μ_2 u_t(x,t-τ) = b|u|^(p-2) u in a bounded domain. Under appropriate ... In this paper, we consider the following viscoelastic wave equation with delay|u_t|~ρu_(tt)-△u-△u_(tt)+∫_0~t g(t-8)△u(8)d8 + μ_1 u_t(x,t) + μ_2 u_t(x,t-τ) = b|u|^(p-2) u in a bounded domain. Under appropriate conditions on μ1, μ2, the kernel function g, the nonlinear source and the initial data, there are solutions that blow up in finite time. 展开更多
关键词 BLOW up nonlinear SOURCE WAVE EQUATION DELAY VISCOELASTIC
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Injection molding of micro patterned PMMA plate 被引量:2
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作者 Yeong-Eun YOO Tae-Hoon KIM +3 位作者 Tae-Jin JE Doo-Sun CHOI Chang-Wan KIM Sun-Kyung KIM 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第A01期148-152,共5页
A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications... A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 mm×213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 mm. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate (PMMA) was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured. 展开更多
关键词 PMMA 注塑成型 塑料板 图案 聚甲基丙烯酸甲酯 压力上升 加工模式 位置测量
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Easy calibration method of vision system for in-situ measurement of strain of thin films 被引量:3
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作者 Jun-Hyub PARK Dong-Joong KANG +5 位作者 Myung-Soo SHIN Sung-Jo LIM Son-Cheol YU Kwang-Soo LEE Jong-Eun HA Sung-Hoon CHOA 《中国有色金属学会会刊:英文版》 CSCD 2009年第B09期243-249,共7页
An easy calibration method was presented for in-situ measurement of displacement in the order of nanometer during micro-tensile test for thin films by using CCD camera as a sensing device. The calibration of the sensi... An easy calibration method was presented for in-situ measurement of displacement in the order of nanometer during micro-tensile test for thin films by using CCD camera as a sensing device. The calibration of the sensing camera in the system is a central element part to measure displacement in the order of nanometer using images taken with the camera. This was accomplished by modeling the optical projection through the camera lens and relative locations between the object and camera in 3D space. A set of known 3D points on a plane where the film is located on is projected to an image plane as input data. These points, known as a calibration points, are then used to estimate the projection parameters of the camera. In the measurement system of the micro-scale by CCD camera, the calibration data acquisition and one-to-one matching steps between the image and 3D planes need precise data extraction procedures and repetitive user's operation to calibrate the measuring devices. The lack of the robust image feature extraction and easy matching prevent the practical use of these methods. A data selection method was proposed to overcome these limitations and offer an easy and convenient calibration of a vision system that has the CCD camera and the 3D reference plane with calibration marks of circular type on the surface of the plane. The method minimizes the user's intervention such as the fine tuning of illumination system and provides an efficient calibration method of the vision system for in-situ axial displacement measurement of the micro-tensile materials. 展开更多
关键词 标定方法 视觉系统 原位测试 应变 薄膜
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Analytical exploration of γ-function explicit method for pseudodynamic testing of nonlinear systems 被引量:2
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作者 张顺益 宋裕祺 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2005年第1期117-127,共11页
It has been well studied that the γ-function explicit method can be effective in providing favorable numerical dissipation for linear elastic systems. However, its performance for nonlinear systems is unclear due to ... It has been well studied that the γ-function explicit method can be effective in providing favorable numerical dissipation for linear elastic systems. However, its performance for nonlinear systems is unclear due to a lack of analytical evaluation techniques. Thus, a novel technique is proposed herein to evaluate its efficiency for application to nonlinear systems by introducing two parameters to describe the stiffness change. As a result, the numerical properties and error propagation characteristics of the γ-function explicit method for the pseudodynamic testing of a nonlinear system are analytically assessed. It is found that the upper stability limit decreases as the step degree of nonlinearity increases; and it increases as the current degree of nonlinearity increases. It is also shown that this integration method provides favorable numerical dissipation not only for linear elastic systems but also for nonlinear systems. Furthermore, error propagation analysis reveals that the numerical dissipation can effectively suppress the severe error propagation of high frequency modes while the low frequency responses are almost unaffected for both linear elastic and nonlinear systems. 展开更多
关键词 地震 非线性系统 数值分散 误差
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Improvement of hydrogen embrittlement and stress corrosion cracking by annealing for Al-4.4Mg-0.6Mn alloy 被引量:1
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作者 Seong-Jong KIM Min-Su HAN +1 位作者 Seong-Kweon KIM Seok-Ki JANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第A01期17-22,共6页
With no annealing treatment, cathodic polarization trends in 5083F Al alloy revealed concentration polarization and activation polarization. However, the annealed specimens have lower current densities at corrosion pr... With no annealing treatment, cathodic polarization trends in 5083F Al alloy revealed concentration polarization and activation polarization. However, the annealed specimens have lower current densities at corrosion protection potential compared to the non-annealed specimen. The results of SSRTs conducted in seawater at the applied potential range of -1.8 V to -0.5 V indicated that the maximum tensile strength, elongation, and time-to-fracture had high values at applied potentials of –0.7 to –1.4 V. The maximum tensile strength, elongation, and time-to-fracture decreased when the potential values were beyond this range in either anodic or cathodic direction. In general, the increased shear lip caused by annealing treatment indicates elongation. Time-to-fracture would likely increase with elongation. Potentials between –0.5 V to –0.6 V were found to be in the region of stress corrosion cracking. The corrosion protection zone was determined to be –0.7 V to –1.4 V because these potential ranges produced good mechanical properties. Potential less than –1.4 V produced a fractured surface with a mixture of dimples (ductile fractures) and a quasi-cleavage pattern resulting from the effects of hydrogen gas. 展开更多
关键词 应力腐蚀开裂 退火处理 合金 氢脆 浓度极化 阴极极化 保护电位 拉伸强度
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The brazing of diamond 被引量:2
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作者 Sung Michael Sung James C. 《金刚石与磨料磨具工程》 CAS 北大核心 2008年第S1期134-142,共9页
Diamond grits held in metal matrix(sintered or electroplated) are retained primary by mechanical locking.Because of this weak attachment,the pullouts of diamond from matrix are inevitable during the cutting process.Mo... Diamond grits held in metal matrix(sintered or electroplated) are retained primary by mechanical locking.Because of this weak attachment,the pullouts of diamond from matrix are inevitable during the cutting process.Moreover,the working grits have low protrusion heights,so the cutting speed of the tool is limited. Furthermore,the rubbing of metal matrix and the work object can cause thermal damages of diamond and other materials,and power increase for the operation. Diamond can be firmly held in a metal matrix by brazing.Because of the presence of strong chemical bonding,diamond grits can protrude twice as high without being knocked off from the matrix.As a result,the cutting speed of the tool may be doubled. When the braze melts,the carbide formers will migrate toward diamond to form carbide at the interface. This reaction may be excessive as to degrade diamond significantly.In this case,a coating on diamond may be needed to moderate the reaction. When diamond is brazed on the surface of a substrate,the melt tends to pull the grits closer together that may thicken the braze layer locally.The clustering of grits can reduce the cutting effectiveness of the diamond tool.A diamond grid design is necessary to maintain the uniform thickness of the braze layer.Moreover,the controlled melting of braze alloy can form a gentle slope around each diamond grit.Such a massive support can allow aggressive cutting of the diamond tool with a low power consumption. 展开更多
关键词 DIAMOND BRAZING DIAMOND DRESSER pad CONDITIONER DIAMOND ADHERENCE DIAMOND distribution chemical mechanical PLANARIZATION
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Reliability of flip-chip bonded RFID die using anisotropic conductive paste hybrid material 被引量:1
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作者 Jun-Sik LEE Jun-Ki KIM +2 位作者 Mok-Soon KIM Namhyun KANG Jong-Hyun LEE 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第A01期175-181,共7页
A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency ide... A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency identification(RFID) inlay. The optimization condition for flip-chip bonding was determined from the behavior of bonding strength. Under the optimized condition, the shear strength for the antenna printed with paste-type Ag ink was larger than that for Cu antenna. Furthermore, an identification distance was varied from the antenna materials. Comparing with the Ag antenna pattern, the as-bonded die on Cu antenna showed a larger distance of identification. However, the long-term reliability of inlay using the Cu antenna was decreased significantly as a function of aging time at room temperature because of the bended shape of Cu antenna formed during the flip-chip bonding process. 展开更多
关键词 可靠性调查 混合材料 倒装芯片 各向异性 RFID 导电膏 无线电频率识别 天线方向图
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