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Deep Drawing Process Using a Tractrix Die for Manufacturing Liners for a CNG High-Pressure Vessel(Type Ⅱ)

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Chinese Journal of Mechanical Engineering 2022年第1期35卷 132-143页

作者： Gun‑Young park Hyo‑Seo Kwak Hyo‑seong Jang Chul Kim School of Mechanical Engineering Pusan National UniversityPusan 46241South Korea Department of Mechanical Engineering Dong-eui UniversityPusan 47340Korea.

The liner of a CNG pressure vessel is manufactured by a DDI(deep drawing and ironing)process for the cylinder part,which is a continuous process that includes a drawing process to reduce the diameter of the billet and a subsequent ironing process to reduce the thickness of the billet.A tractrix die used in the 1^(st) deep drawing allows the blank to flow smoothly by decreasing the punch load and radial tensile stress occurring in the *** also increases the draw ratio compared to conventional dies,but it causes forming *** this study,a shape coefficient(S_(c))is proposed for the tractrix die using the blank diameter(D_(0)),inflow diameter of the workpiece(d_(i)),and inflow angle of the workpiece(θ)for design of the tractrix *** effects of the thickness and inflow angle of the workpiece on wrinkling and folding were investigated through ***,a discriminant is proposed for the relative radial stress(σ)generated during the deep drawing process using the tractirx die and used to predict *** on the results,the blank thickness,the draw ratio,and the inflow of the workpiece angle in the 1^(st) deep drawing process are suggested,and the number of operations in the DDI process was reduced from 6 to *** improves the productivity and reduces the manufacturing cost.

关键词： Tractrix die Deep drawing Wrinkling Folding LDR(Limit draw ratio) FEM

Priapism secondary to penile metastasis of rectal cancer

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World Journal of Gastroenterology 2009年第33期15卷 4209-4211页

作者： Ji Chan park wook Hyun Lee Min Kyu Kang Suk Young park Division of Oncology Department of Internal MedicineThe Catholic University of KoreaDaejeon St. Mary's Hospital

Metastatic penile carcinoma is rare and usually originates from genitourinary tumors. The presenting symptoms or signs have been described as nonspecific except for priapism. Rectal adenocarcinoma is a very unusual source of metastatic penile carcinoma. We report a case of metastatic penile carcinoma that originated from the rectum. Symptomatic improvement occurred with palliative radiotherapy.

关键词： Penile neoplasms Neoplasm metastasis Priapism Rectal cancer

A Compact Tri-Band Antenna Based on Inverted-L Stubs for Smart Devices

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Computers, Materials & Continua 2022年第2期70卷 3321-3331页

作者： Niamat Hussain Anees Abbas Sang-Myeong park seong Gyoon park Nam Kim Department of Information and Communication Engineering Chungbuk National UniversityCheongju28644Korea Department of Information and Communication Engineering Kongju National UniversityKongju32588Korea

We designed and constructed a novel,compact tri-band monopole antenna for intelligent *** behavior was achieved by placing inverted-L shaped stubs of various lengths in a triangular monopole antenna fed by a coplanar *** resonance frequency of each band can be controlled by varying the length of the corresponding *** bands,at 2.4(2.37-2.51),3.5(3.34-3.71),and 5.5(4.6-6.4)GHz,were easily obtained using three stubs of different *** miniaturization,a portion of the longest stub(at 2.4 GHz)was printed on the opposite side of the substrate,and connected to the main stub via a shorting *** validate the concept,the antenna was fabricated on a low-cost 1.6-mm-thick FR-4 substrate with dimensions of 20×15×1.6 mm^(3).The antenna exhibited a moderate average gain of 2.9 dBi with an omnidirectional radiations over the bandwidths required for RFID,Bluetooth,ISM,WiMAX,andWLAN-band *** features make the antenna suitable for compact smart devices.

关键词： Multiband antenna compact antenna tri-band antenna CPW antenna stub-loaded antenna

Newly diagnosed diabetes mellitus patients presenting with proliferative diabetic retinopathy as an initial sign

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International Journal of Ophthalmology(English edition) 2014年第1期7卷 173-178页

作者： Hoon park Young Gyun Kim Jong wook Lee Jong Seok park Department of Ophthalmology Eulji Hospital

AIM: To investigate the clinical features of newly diagnosed diabetes mellitus(NDM) patients showing proliferative diabetic retinopathy(PDR) as an initial sign. ·METHODS: As a retrospective case series,the medical records of a total of four hundred and thirty-two patients who underwent a vitrectomy due to PDR were reviewed to find the subjects. Of 432 patients,six cases of NDM patients showing PDR as an initial sign were included and analyzed with their systemic and ocular features. Main outcome measures: the systemic features and ocular features [preoperative and postoperative best corrected visual acuity(BCVA),intraoperative findings]. ·RESULTS: The mean onset age of visual symptoms was 36.3 years old. The mean serum insulin and C-peptide titer was below the normal range. The mean fasting plasma glucose was 178mg/dL and the mean postprandial 2h plasma glucose was 306mg/dL. The mean HbA1c at diagnosis was 11.02%. In all cases,an acute progressive fibrovascular proliferation was observed. Intraoperative retinal tears were found in three cases of six. The mean preoperative BCVA was +0.67 ± 0.58 logMAR and the mean BCVA at postoperative 6 months was +0.20±0.30 logMAR. ·CONCLUSION: All patients were considered to have latent autoimmune diabetes in adults(LADA). A rapid deterioration of kidney function as well as poor diabetic control status at diagnosis was observed in all six cases. The ocular features of the patients showed acute progressive fibrovascular proliferation and relatively favorable postoperative visual acuity.

关键词： fibrovascular proliferation latent autoimmune diabetes in adults diabetes mellitus proliferative diabetic retinopathy

Lightweight design of 45000r/min spindle using full factorial design and extreme vertices design methods

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Journal of Central South University 2011年第1期18卷 153-158页

作者： park seong-jin LEE Choon-man HWANG Young-kug Department of Mechanical Design and Manufacturing Engineering Changwon National University

Factors for determining the spindle size are the shaft diameter, positions of bearing and motor, and entire length of the spindle. Then, it is important to find the assembling of the optimal design variables, which satisfy the stiffimss and rotational speed required to the spindle. A general full factorial design method was used to verify some factors that affect the natural frequency of a spindle. It is verified that the shorter shaft length and bearing span length represent the higher natural frequency, and there are some effects according to the change in the levels of factors. The detailed spindle dimension is determined by applying an EVD method, which can define the optimal bearing position through considering the limiting condition. Based on the estimated regression model, the optimal spindle size and bearing distance that can improve the primary natural frequency are obtained, and the influence of design factors on the natural frequency is also analyzed.

关键词： high-speed spindle extreme vertices design natural frequency lightweight design full factorial design

Development of 3D bicontinuous metal-intermetallic composites through subsequent alloying process after liquid metal dealloying

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Journal of Magnesium and Alloys 2023年第11期11卷 4274-4281页

作者： Jee Eun Jang Jihye seong Soo-Hyun Joo Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials Science and Engineering Dankook UniversityCheonan 31116Republic of Korea

This study presents a novel process for the fabrication of metal-intermetallic composites with a 3D bicontinuous structure, achieved through a combination of liquid metal dealloying(LMD) and subsequent alloying. Initially, porous Ti structures are produced using the LMD process, followed by immersion in a molten Mg-3Al(wt%) metal. Due to the higher thermodynamic miscibility of Al with Ti compared to Mg, the concentration of Al in the Ti matrix increases as the immersion time increases. This results in a sequential phase transition within the Ti matrix: α-Ti → Ti_(3)Al → Ti Al. The phase transition considerably affects the hardness and strength of the composite material,with the Mg-Ti_(3)Al-Ti Al composite exhibiting a maximum hardness nearly twice as high as that of the conventional Mg-Ti composite. This innovative process holds potential for the development of various bicontinuous metal-intermetallic composites.

关键词： Liquid metal dealloying Subsequent alloying Metal–intermetallic composite 3D bicontinuous structure Hardness

Improvement of Shape Recognition Performance of Sendzimir Mill Control Systems Using Echo State Neural Networks

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Journal of Iron and Steel Research International 2014年第3期21卷 321-327页

作者： Jung-hyun park seong-ik HAN Jong-shik KIM School of Mechanical Engineering Pusan National University School of Electrical Engineering Pusan National University

High rigidity twenty-high Sendzimir mills （ZRMs） are widely used for rolling stainless steels, silicon sheets, etc. A ZRM uses a small diameter work roll to produce massive rolling forces. Since a work roll with a small diameter can be bent easily, strips often have complex shapes with mixed quarter and deep edge waves in the shape of plates. In order to solve this problem, fuzzy neural network controls are generally used for shape： recognition in ZRM control systems. Among various neural network types, the multi-layer perceptron （MLP） is typically used in current ZRMs. However, an MLP causes the loss of a large amount of shape recognition data. To improve the shape recognition per- formance of ZRM control systems, echo state networks （ESNs） are proposed to be used. Through simulation re- sults, it is found that shape recognition performance could be improved using the proposed ESN method.

关键词： Sendzimir mill neural network multi-layer perceptron echo state network shape recognition

Optimization of thermoelectric properties of n-type Bi_2(Te,Se)_3 with optimizing ball milling time

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Rare Metals 2018年第4期37卷 351-359页

作者： Ji-Hee Son Min-wook Oh Bong-Seo Kim Su-Dong park Thermoelectric Conversion Research Center Korea Electrotechnology Research Institute Department of Materials Science and Engineering Hanbat National University

The thermoelectric properties at elevated temperature were investigated for n-type Bi2（Te,Se）3 which is obtained from ball milling processed powder with various milling times. Electrical properties such as electrical resistivity and Seebeck coefficient are clearly dependent on milling time, in which the carrier concentration is attributed to the change of the electrical properties. The concentrations of the defects are also varied with the ball milling time, which is the origin of the carrier concentration variation. Even though finer grain sizes are obtained after the long ball milling time, the temperature dependence of the thermal conductivity is not solely understood with the grain size, whereas the electrical contribution to the thermal conductivity should be also considered. The highest figure of merit value of ZT = 0.83 is achieved at 373 K for the optimized samples, in which ball milling time is 10 h. The obtained ZT value is 48% improvement over that of the 0.5-h sample at 373 K.

关键词： Thermoelectric properties Ball milling Bi2Te3 Seebeck coefficient Grain size Thermalconductivity

Exercise-induced muscle fatigue in the unaffected knee joint and its influence on postural control and lower limb kinematics in stroke patients

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Neural Regeneration Research 2017年第5期12卷 765-769页

作者： Sun wook park Sung Min Son Na Kyung Lee Department of Physical Therapy Faculty of Health Science Eulji University Department of Physical Therapy College of Health Science Cheongju University Department of Physical Therapy College of Rehabilitation Science Daegu University

This study aimed to investigate the effects of exercise-induced muscle fatigue in the unaffected knee joint on postural control and kinematic changes in stroke patients. Forty participants（20 stroke patients, 20 age-matched healthy participants） were recruited. To induce fatigue, maximum voluntary isometric contractions were performed in the unaffected knee joint in a Leg Extension Rehab exercise machine using the pneumatic resistance. We measured static and dynamic balance and lower-limb kinematics during gait. Changes in postural control parameters anteroposterior sway speed and total center of pressure distance differed significantly between the stroke and control groups. In addition, changes in gait kinematic parameters knee and ankle angles of initial contact differed significantly between stroke（paretic and non-paretic） and control groups. Muscle fatigue in the unaffected knee and ankle impaired postural control and debilitates kinematic movement of ipsilateral and contralateral lower limbs, and may place the fatigued stroke patients at greater risk for falls.

关键词： nerve regeneration knee muscle fatigue stroke postural control gait kinemetics neural regeneration