检索结果-南通市图书馆

Evaluation of defects in aluminum piston castings by using ultrasonics and computer tomography

在线全文

学校读者我要写书评

暂无评论

China Foundry 2012年第3期9卷 275-278页

作者： In-Sung Cho Jeong-ho Hwang Jin-Seok Yang Seung-Mok Yoo chae-ho lim Korea Institute of Industrial Technology

Pistons used in automobile engines are made of aluminum alloy; and endurance of high pressure and high temperature is required. Recently, high strength pistons are needed to cope with the increase of pressure and temperature in the engine cylinder. A high strength piston is possible when the piston casting has little or no casting defects, such as micro-pores and cracks. Generally the defects can be evaluated by non-destructive testing (NDT), and the most efficient ways for evaluation are using ultrasonics and computer tomography. In the present study, two NDT methods were compared and evaluated to investigate the defects in the aluminum piston castings. Artificial defects were machined by using very small drill bits with diameters 1, 0.5, 0.3, 0.2 and 0.1 mm. The defects were investigated by using an ultrasonic tester and a computer tomography system. Defects smaller than 0.3 mm may not be found by using the ultrasonic test, but the defects may be found by using the computer tomography system. The investigation conditions for detecting small defects and the scanning time for in-line defect analysis are discussed in the present study.

关键词： piston ultrasonic test computer tomography aluminum defect

A review of understanding electrocatalytic reactions in energy conversion and energy storage systems via scanning electrochemical microscopy

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第4期91卷 155-177页

作者： Jihye Park Jong Hwan lim Jin-Hyuk Kang Jiheon lim ho Won Jang hosun Shin Sun Hwa Park Interdisciplinary Materials Measurement Institute Korea Research Institute of Standards and ScienceDaejeon 34113Republic of Korea Department of Material Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Department of Applied Measurement Science University of Science and TechnologyDaejeon 34113Republic of Korea

To address climate change and promote environmental sustainability,electrochemical energy conversion and storage systems emerge as promising alternative to fossil fuels,catering to the escalating demand for *** optimal energy efficiency and cost competitiveness in these systems requires the strategic design of electrocatalysts,coupled with a thorough comprehension of the underlying mechanisms and degradation behavior occurring during the electrocatalysis *** electrochemical microscopy(SECM),an analytical technique for studying surface electrochemically,stands out as a powerful tool offering electrochemical *** possesses remarkable spatiotemporal resolution,enabling the visualization of the localized electrochemical activity and surface *** review compiles crucial research findings and recent breakthroughs in electrocatalytic processes utilizing the SECM methodology,specifically focusing on applications in electrolysis,fuel cells,and metal–oxygen batteries within the realm of energy conversion and storage *** with an overview of each energy system,the review introduces the fundamental principles of SECM,and aiming to provide new perspectives and broadening the scope of applied research by describing the major research categories within SECM.

关键词： Scanning electrochemical microscopy Electrocatalyst Electrocatalysis Water splitting Fuel cell Metal-oxygen battery

Protein Arginine Methyltransferase 1 Ablation in Motor Neurons Causes Mitochondrial Dysfunction Leading to Age-related Motor Neuron Degeneration with Muscle Loss

在线全文

学校读者我要写书评

暂无评论

Research 2024年第1期2023卷 637-649页

作者： Hyun-Kyung So Hyebeen Kim Jinwoo Lee Chang-lim You chae-Eun Yun Hyeon-Ju Jeong Eun-Ju Jin Yunju Jo Dongryeol Ryu Gyu-Un Bae Jong-Sun Kang Department of Molecular Cell Biology Sungkyunkwan University School of MedicineSuwonKorea Single Cell Network Research Center Sungkyunkwan University School of MedicineSuwonKorea Research Institute of Aging-Related Diseases AniMusCureInc.SuwonKorea Drug Information Research Institute Muscle Physiome Research CenterCollege of PharmacySookmyung Women’s UniversitySeoulKorea

Neuromuscular dysfunction is tightly associated with muscle wasting that occurs with age or due to degenerative ***,the molecular mechanisms underlying neuromuscular dysfunction are currently *** studies have proposed important roles of Protein arginine methyltransferase 1(Prmt1)in muscle stem cell function and muscle *** the current study,we set out to determine the role of Prmt1 in neuromuscular function by generating mice with motor neuron-specific ablation of Prmt1(mnKO)using *** exhibited age-related motor neuron degeneration and neuromuscular dysfunction leading to premature muscle loss and ***1 deficiency also impaired motor function recovery and muscle reinnervation after sciatic nerve *** transcriptome analysis of aged mnKO lumbar spinal cords revealed alterations in genes related to inflammation,cell death,oxidative stress,and ***,mnKO lumbar spinal cords of sciatic nerve injury model or aged mice exhibited elevated cellular stress response in motor ***,Prmt1 inhibition in motor neurons elicited mitochondrial *** findings demonstrate that Prmt1 ablation in motor neurons causes agerelated motor neuron degeneration attributing to muscle ***,Prmt1 is a potential target for the prevention or intervention of sarcopenia and neuromuscular dysfunction related to aging.

关键词： degeneration impaired prevention

Efficacy of chemotherapy containing bevacizumab in patients with metastatic colorectal cancer according to programmed cell death ligand 1

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 Gastrointestinal Oncology 2024年第8期16卷 3521-3528页

作者： Shin Woo Kang Sung Hee lim Min-Ji Kim Jeeyun Lee Young Suk Park ho Yeong lim Won Ki Kang Seung Tae Kim Division of Hematology Oncology Department of MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoul 06351South Korea Samsung Biomedical Research Institute Samsung Medical CenterSeoul 06351South Korea

BACKGROUND Bevacizumab,an anti-vascular endothelial growth factor(VEGF)monoclonal antibody,inhibits angiogenesis and reduces tumor *** VEGF-C,lactate dehydrogenase,and inflammatory markers have been reported as predictive markers related to bevacizumab *** cell death ligand 1(PD-L1)could act upon VEGF receptor 2 to induce cancer cell angiogenesis and *** To investigate the efficacy of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer(CRC)according to the expression of *** This analysis included CRC patients who received bevacizumab plus FOLFOX or FOLFIRI as first-line therapy between June 24,2014 and February 28,2022,at Samsung Medical Center(Seoul,South Korea).Analysis of patient data included evaluation of PD-L1 expression by the combined positive score(CPS).We analyzed the efficacy of bevacizumab according to PD-L1 expression status in patients with *** A total of 124 patients was included in this *** all patients were treated with bevacizumab plus FOLFIRI or FOLFOX as the first-line *** 77%of patients received FOLFOX,23%received FOLFIRI as backbone first-line *** numbers of patients with a PD-L1 CPS of 1 or more,5 or more,or 10 or more were 105(85%),64(52%),and 32(26%),*** results showed no significant difference in progression-free survival(PFS)and overall survival(OS)with bevacizumab treatment between patients with PDL1 CPS less than 1 and those with PD-L1 CPS of 1 or more(PD-L1<1%vs PD-L1≥1%;PFS:P=0.93,OS:P=0.33),between patients with PD-L1 CPS less than 5 and of 5 or more(PD-L1<5%vs PD-L1≥5%;PFS:P=0.409,OS:P=0.746),and between patients with PD-L1 CPS less than 10 and of 10 or more(PD-L1<10%vs PD-L1≥10%;PFS:P=0.529,OS:P=0.568).CONCLUSION Chemotherapy containing bevacizumab can be considered as first-line therapy in metastatic CRC irrespective of PD-L1 expression.

关键词： Bevacizumab Colorectal cancer Programmed cell death ligand 1 expression First-line chemotherapy Metastatic colorectal cancer

Long-term outcomes of very low birth weight infants with intraventricular hemorrhage:a nationwide population study from 2011 to 2019

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 Pediatrics 2024年第7期20卷 692-700页

作者： Joonsik Park Sook-Hyun Park Yu-ra Kwon So Jin Yoon Joo Hee lim Jung ho Han Jeong Eun Shin ho Seon Eun Min Soo Park Soon Min Lee Department of Pediatrics Yonsei University College of Medicine211 Eonjuro GangnamguSeoul 06273Republic of Korea

Background Advancements in neonatal care have increased preterm infant survival but paradoxically raised intraventricular hemorrhage(IVH)*** study explores IVH prevalence and long-term outcomes of very low birth weight(VLBW)infants in Korea over a *** Using Korean National Health Insurance data(NHIS,2010-2019),we identified 3372 VLBW infants with IVH among 4,129,808 live ***-related claims data,encompassing diagnostic codes,diagnostic test costs,and administered procedures were sourced from the NHIS *** results of the developmental assessments are categorized into four groups based on standard deviation(SD)*** characteristics and complications were compared among the *** regression models were employed to identify significant changes in the incidence of complications and to calculate odds ratios with corresponding 95%confidence intervals for each risk factor associated with mortality and morbidity in ***-term growth and development were compared between the two groups(years 2010-2013 and 2014-2017).Results IVH prevalence was 12%in VLBW and 16%in extremely low birth weight(ELBW)*** the past decade,IVH rates increased significantly in ELBW infants(P=0.0113),while mortality decreased(P=0.0225).Major improvements in certain neurodevelopmental outcomes and reductions in early morbidities have been observed among VLBW infants with *** percent of the population received surgical treatments such as external ventricular drainage(EVD)or a ventriculoperitoneal(VP)shunt,with the choice of treatment methods remaining consistent over *** IVH with surgical intervention group exhibited higher incidences of delayed development,cerebral palsy,seizure disorder,and growth failure(height,weight,and head circumference)up to 72 months of age(P<0.0001).Surgical treatments were also significantly associated with abnormal developmental screening test *** The neurodevelopmental outcomes of infa

关键词： Cerebral intraventricular hemorrhage Developmental Hydrocephalus Mortality Posthemorrhagic ventricular dilatation Surgery

Novel N-doped multichannel carbon nanofiber architecture with porous CoS nanoprisms for high-performance potassium-ion batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第3期43卷 971-983页

作者： Jae Bong lim Seung-Keun Park Department of Advanced Materials Engineering Chung-Ang UniversityGyeonggi-do17546Republic of Korea Department of Intelligence Energy and Industry Chung-Ang UniversitySeoul06974Republic of Korea Western Seoul Center Korea Basic Science InstituteSeoul03759Republic of Korea

Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low ***,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical ***,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance *** CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat *** porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge *** addition,numerous pores facilitated the transport of electrons and ***,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).

关键词： K-ion batteries Cobalt sulfide Multichannel structured composite Electrospinning Nanoprism Porous structure

Crystallographically vacancy‐induced MOF nanosheet as rational single‐atom support for accelerating CO_(2)electroreduction to CO

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第8期6卷 49-62页

作者： Jin Hyuk Cho Joonhee Ma chaehyeon Lee Jin Wook lim Youngho Kim ho Yeon Jang Jaehyun Kim Myung‐gi Seo Youngheon Choi Youn Jeong Jang Sang Hyun Ahn ho Won Jang Seoin Back Jong‐Lam Lee Soo Young Kim Department of Materials Science and Engineering Korea UniversitySeoulRepublic of Korea Department of Chemical and Biomolecular Engineering Sogang UniversitySeoulRepublic of Korea Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)PohangRepublic of Korea Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoulRepublic of Korea Lotte Chemical R&D Center DaejeonRepublic of Korea Department of Chemical Engineering Hanyang UniversitySeoulRepublic of Korea School of Chemical Engineering and Material Science Chung‐Ang UniversitySeoulRepublic of Korea

To attain a circular carbon economy and resolve CO_(2)electroreduction technology obstacles,single‐atom catalysts(SACs)have emerged as a logical option for electrocatalysis because of their extraordinary catalytic *** SACs,metal–organic frameworks(MOFs)have been recognized as promising support materials because of their exceptional ability to prevent metal *** study shows that atomically dispersed Ni single atoms on a precisely engineered MOF nanosheet display a high Faradaic efficiency of approximately 100%for CO formation in H‐cell and three‐compartment microfluidic flow‐cell reactors and an excellent turnover frequency of 23,699 h−1,validating their intrinsic catalytic *** results suggest that crystallographic variations affect the abundant vacancy sites on the MOF nanosheets,which are linked to the evaporation of Zn‐containing organic linkers during ***,using X‐ray absorption spectroscopy and density functional theory calculations,a comprehensive investigation of the unsaturated atomic coordination environments and the underlying mechanism involving CO^(*)preadsorbed sites as initial states was possible and provided valuable insights.

关键词： 2‐dimensional material carbon dioxide reduction metal-organic frameworks single‐atom catalysts vacancy sites

A short overview of the lead iodide residue impact and regulation strategies in perovskite solar cells

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 504-510,I0012页

作者： Eng Liang lim Zhanhua Wei Xiamen Key Laboratory of Optoelectronic Materials and Advanced Manufacturing Institute of Luminescent Materials and Information DisplaysCollege of Materials Science and EngineeringHuaqiao UniversityXiamen 361021FujianChina

Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a *** other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the *** moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so *** PbI2 residue will reduce the interfacial passivation effect and device *** addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device ***,the impact and regulation of PbI2 residue on the device performance and stability is still not fully ***,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and ***,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.

关键词： Lead iodide Residue Regulation Perovskite solar cells Efficiency Stability

Reconfigurable transmissive metasurface with a combination of scissor and rotation actuators for independently controlling beam scanning and polarization conversion

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第2期10卷 173-180页

作者： Chhunheng Lor Ratanak Phon Sungjoon lim Intelligent Semiconductor Engineering Chung-Ang UniversityHeukseok-DongDongjak-GuSeoul06974Republic of Korea School of Electrical and Electronic Engineering Chung-Ang UniversityHeukseok-DongDongjak-GuSeoul06974Republic of Korea

Polarization conversion and beam scanning metasurfaces are commonly used to reduce polarization mismatch and direct electromagnetic waves in a specific direction to improve the strength of a wireless ***,identifying suitable active and mechanically reconfigurable metasurfaces for polarization conversion and beam scanning is a considerable challenge,and the reported metasurfaces have narrow scanning ranges,are expensive,and cannot be independently *** this paper,we propose a reconfigurable transmissive metasurface combined with a scissor and rotation actuator for independently controlling beam scanning and polarization conversion *** metasurface is constructed with rotatable unit cells(UCs)that can switch the polarization state between right-handed(RHCP)and left-handed circular polarization(LHCP)by flipping the UCs to reverse their phase ***,independent beam scanning is achieved using the scissor actuator to linearly change the distance between the *** and experimental results confirm that the proposed metasurface can perform beam scanning in the range of 28°for both the positive and negative regions of a radiation pattern(RHCP and LHCP beams)at an operational frequency of 10.5 GHz.

关键词： beam rotation controlling