检索结果-南通市图书馆

Cavity noise sensitivity analysis of tire contour design factors and application of contour optimization methodology

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2012年第8期19卷 2386-2393页

作者： KIM Seong-rae SUNG Ki-deug lee dong-woo HUH Sun-chul NEXEN Tire Corporation 30 Yusan-DongYangsan-SiKyungnam 626-230Korea Division of Automotive and Mechanical Engineering Changwon Moonsung University91Doodae-dongChangwon-si Kyungnam 641-771Korea Department of Energy and Mechanical Engineering Institute of Marine IndustryGyeongsang National University Cheondaeguk-Gil 38TongyeongGyeongnam 650-160Korea

Cavity resonance noise of passenger car tires is generated by interacting excitation between a tire structure and the fill gas (air), and generally lies in a frequency range of 200?250 Hz. As such, this noise is strongly perceived and may be a serious source of driver annoyance. Thus, many studies regarding the cavity noise mechanism and its reduction have already been conducted. In this work, a vibro-acoustic coupled analysis was conducted between a tire structure and air cavity. Using this analysis, we can more accurately simulate the tire noise performance in the region of the cavity resonance frequency. An analysis of the effects of variation of tire contour design factors was conducted, using design-of-experiments methods. Finally, a multi-objective optimization was performed using in-house codes to reduce the cavity noise level while minimizing the loss of other performances, such as diminished ride comfort and handling caused by the variations of contour. As a result of this optimization, an optimized contour shape was derived, which satisfied the multi-objective performances.

关键词： tire cavity noise vibro-acoustic coupled analysis finite element method boundary element method (BEM) sensitivity optimization

Nasal cavity fungus ball discovered accidentally:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2025年第5期13卷 44-48页

作者： Dae-Neung lee dong Hoon lee Sang Chul Lim Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolChonnam National University Hwasun HospitalHwasun 58128South Korea Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolHwasun HospitalChonnam National University Hwasun HospitalHwasun 58128South Korea Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolKwangju 501190South Korea

BACKGROUND Fungal balls within the nasal cavity are an exceedingly rare clinical entity,typically presenting with nonspecific symptoms or being identified *** SUMMARY This report presents an incidental discovery of a fungal ball in the nasal cavity during routine imaging,with no associated clinical *** This case underscores the importance of considering the possibility of asympto-matic presentations of nasal fungal balls,which may be detected incidentally during imaging evaluations.

关键词： Fungi Mycoses Fungus ball Nasal cavity Nasal surgical procedures Case report

Aligned Ion Conduction Pathway of Polyrotaxane‑Based Electrolyte with Dispersed Hydrophobic Chains for Solid‑State Lithium–Oxygen Batteries

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第2期17卷 169-186页

作者： Bitgaram Kim Myeong‑Chang Sung Gwang‑Hee lee Byoungjoon Hwang Sojung Seo Ji‑Hun Seo dong‑Wan Kim Department of Materials Science and Engineering Korea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea School of Civil Environmental and Architectural EngineeringKorea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea Materials Science and Chemical Engineering Center Institute for Advanced Engineering(IAE)Yongin 17180Republic of Korea

A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety *** study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves ***-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain *** this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 *** situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen *** situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability *** present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

关键词： Solid polymer electrolyte Lithium-oxygen batteries Polyrotaxane ion conductivity Hydrophobic chain

Improvement in Background Error Covariances Using Ensemble Forecasts for Assimilation of High-Resolution Satellite Data

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2011年第4期28卷 758-774页

作者： Seung-woo lee dong-Kyou lee School of Earth and Environmental Sciences Seoul National University

Satellite data obtained over synoptic data-sparse regions such as an ocean contribute toward improving the quality of the initial state of limited-area models. Background error covariances are crucial to the proper distribution of satellite-observed information in variational data assimilation. In the NMC （National Meteorological Center） method, background error covariances are underestimated over data-sparse regions such as an ocean because of small differences between different forecast times. Thus, it is necessary to reconstruct and tune the background error covariances so as to maximize the usefulness of the satellite data for the initial state of limited-area models, especially over an ocean where there is a lack of conventional data. In this study, we attempted to estimate background error covariances so as to provide adequate error statistics for data-sparse regions by using ensemble forecasts of optimal perturbations using bred vectors. The background error covariances estimated by the ensemble method reduced the overestimation of error amplitude obtained by the NMC method. By employing an appropriate horizontal length scale to exclude spurious correlations, the ensemble method produced better results than the NMC method in the assimilation of retrieved satellite data. Because the ensemble method distributes observed information over a limited local area, it would be more useful in the analysis of high-resolution satellite data. Accordingly, the performance of forecast models can be improved over the area where the satellite data are assimilated.

关键词： 3DVAR background error covariances retrieved satellite data assimilation ensemble forecasts.

Creep and tensile properties of press molding joined GMT-sheets

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 170-174页

作者： Jin-woo KIM dong-Gi lee Center for NDE Iowa State University Department of Mechatronics Engineering Chosun University

GMT-sheet is used in automobile bumper with high rigidity and strength, and its joining strength is influenced by lap length, one of the joined molding conditions. Fracture strength was calculated by dividing fracture load with cross-sectional area. Total five repeated measurements were made to obtain the average value. Tensile test was conducted at room temperature for 10 specimens. In addition, the effect of compression ratio on creep and tensile performance during lap joined molding was discussed. With increasing lap length, the lap joining efficiency of GMT-sheet was increased. However, higher compression ratio reduced the joining efficiency. Creep test on GMT-sheet showed abrupt fracture without tertiary creep. This can be explained by the weak thermal resistance of the resin. If GMT-sheet was exposed to high temperature for a long time, it was easily failed by external force.

关键词： GMT-sheet randomly oriented composite unidirectional oriented composite compression ratio lap joint

Impact of Horizontal Resolution and Cumulus Parameterization Scheme on the Simulation of Heavy Rainfall Events over the Korean Peninsula

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2011年第1期28卷 1-15页

作者： Seung-woo lee dong-Kyou lee dong-Eon CHANG School of Earth and Environmental Sciences Seoul National University National Institute of Meteorological Research Korea Meteorological Administration

In this paper, we present the results from high-resolution numerical simulations of three heavy rainfall events over the Korean Peninsula. The numerical results show that the prediction accuracy for heavy rainfall events improved as horizontal resolution increased. The fine-grid precipitation fields were much closer to the real precipitation fields in the case of large synoptic forcing over the Korean Peninsula. In the case of large convective available potential energy and weak synoptic forcing, it seems that even when using a high resolution, the models still showed poor performance in reproducing the observed high precipitation amounts. However, activation of the cumulus parameterization scheme in the intermediate resolution of 9 km, even at a grid spacing of 3 km, had a positive impact on the simulation of the heavy rainfall event.

关键词： high resolution cumulus parameterization scheme heavy rainfall numerical simulation

Bioinspired Segment Robot with Earthworm-like Plane Locomotion

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2016年第2期13卷 292-302页

作者： Chang-woo Song dong-Jun lee Seung-Yop lee Department of Mechanical Engineering Sogang University 1 Shinsu-dong Mapo-gu Seoul 121-742 Republic of Korea

In this paper, a miniaturized segment robot using solenoids is developed to mimic the plane locomotion of earthworms. The bioinspired robot is composed of five segmented bodies, and one segment has two solenoid actuators. This robot can move linearly and it can also turn due to the pair of solenoid actuators that facilitate the earthworm-like peristaltic locomotion. We have designed a miniaturized solenoid with a permanent magnet plunger in order to increase the total electromagnetic force. A theoretical analysis is performed to predict the linear and turning motions of each segment, and the optimal profiles of input signals are obtained for fast locomotion. Experiments are then conducted to determine the linear and turning motions of the segment robot. It takes about 0.5 s for the five segments to complete one cycle of the peristaltic locomotion. In experiments, the segment robot is shown to have the linear and angular velocities of 27.2 mm·s^-1 （0.13 body-length per second） and 2 degrees per second, respectively.

关键词： bioinspired robot earthworm peristaltic locomotion solenoid segmented robot

In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

维普期刊数据库评论

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 Energy Chemistry 2024年第3期90卷 632-651,I0014页

作者： Andi Haryanto Kyounghoon Jung Chan woo lee dong-Wan Kim Department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy *** methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic *** this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the *** addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during *** spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

关键词： Hydrogen evolution reaction Infrared spectroscopy Raman spectroscopy X-ray absorption spectroscopy Reaction mechanism

Systematic Revision of Trilobites from the Middle Ordovician(Darriwilian) Klimoli Formation of the Zhuozishan Area,Inner Mongolia,China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第6期90卷 1955-1975页

作者： lee Seung-Bae lee dong-Chan woo Jusun ZHANG Xingliang Geology Division Korea Institute of Geoscience and Mineral Resources Department of Earth Science Education Chungbuk National University Division of Polar Earth-System Sciences Korea Polar Research Institute Early Life Institute and State Key Laboratory of Continental Dynamics Department of GeologyNorthwest University

New morphologic information permits systematic revision of trilobites from the Middle Ordovician Klimoli Formation of the Zhuozishan area, Ordos Basin, Inner Mongolia. The new assemblage is composed of 10 species of the Raphiophoridae, Nileidae, Asaphidae, and Telephinidae.？ An asaphid, aff. Mioptychopyge lashachungensis （previously Paraptychopyge lashachungensis） displays an intermediate morphology between the Chinese nobiliasaphine genera Mioptychopyge and Zhenganites. The pygidial doublure is regarded as the most significant character to differentiate Symphysurus klimoliensis （previously Nileus klimoliensis） of the Nileidae from such closely allied taxa as Poronileus. A nileid, cf. Peraspis kujandensis displays typical nileid morphology, unlike the type species, Peraspis lineolata, which might turn out to be an asaphid. Ampyx gongwusuensis sp. nov. of the Raphiophoridae is the first record of the genus in the Zhuozishan area and reveals morphologic details that might be employed to resolve Ampyx taxonomy in China. Morphologic differences between A. gongwusuensis and Abulbaspis ordosensis might represent a case of sexual dimorphism.

关键词： Invertebrate paleontology Trilobita systematics Klimoli Formation Darriwilian Zhuozishan Inner Mongolia