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Phase Formation and Magnetic Properties of Nanocomposite Nd-Fe-B Adjusted by Small Amount of Dy and Co

Journal of Rare Earths 2004年第z2期22卷 89-94页

作者： t S Jang t W Lim H S Aum D H lee M B Kim Division of Materials and Chemical Engineering Sun Moon UniversityKorea Division of Materials and Chemical EngineeringSun Moon UniversityKorea Division of Mechanical EngineeringSun Moon University 100 Kalsan LiTangjung MyonAsan CityChoongnam 336-708Korea Division of Materials and Chemical EngineeringSun Moon UniversityKorea Division of Materials and Chemical EngineeringSun Moon UniversityKorea

In order to improve and stabilize the magnetic properties of nanocomposite Nd2Fe14B/α-Fe magnetic alloys by a compositional adjustment, small amount of Dy and/or Co was added to Nd9Fe84B7 alloys. DtA analysis on the amorphous of the alloys took place as the soft magnetic phases were crystallized, and then the hard magnetic Nd2Fe14B was precipitated from them. While α-Fe and a metastable 1:7 (tbCu7-type) phase were formed simultaneously in Dy and Co-free alloys, they were crystallized separately at different temperatures after Dy or Co was added. this phase separation occurred more clearly in the Dy-treated alloys and the other soft magnetic phase Fe3B was also stabilized by Dy and/or Co. the 1: 7 phase that was stabilized by Dy and/or Co was not eliminated at 700 ℃, decreasing magnetic properties of the alloys. It was eventually disappeared above 725 ℃, but Fe3B was not eliminated even at 750 ℃ when Dy was added more than 0.5 at% or Co was added more than 2.0 at%. Amount of Nd2Fe14B in the alloys tended to increase as Dy addition increased,whereas Co addition did not lead to any appreciable change in the ratio of α-Fe and Nd2Fe14B. Moreover, Dy addition apparently increased coercivity of an alloy while Co addition had a beneficial effect on remanence. the grains in the Dytreated alloys were usually finer than those in the Co-treated alloys. the grain size of both α-Fe and Nd2Fe14B in the alloys exhibiting mr ≥ 0.72 was in the range of 20 ～ 40 nm or even larger 50 nm, which is larger than the theoretical optimum size ( ～ 10 nm). typical magnetic properties obtained from a Nd7.5Dy1.5Fe82.5Co1.5B7 alloy annealed for 12 min at 725 ℃were iHc=4.85 kOe, Br= 11.32 kG, (BH)max = 15.73 MGOe, and mr=0.73.

关键词： nanocomposite Nd-Fe-B magnetic properties remanence coercivity

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Analyzing the H19-and t65-epitopes in 38 kd phosphory-lated protein of Marek's disease viruses and comparing chicken immunological reactions to viruses point-mutated in the epitopes

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Science China(Life Sciences) 2004年第1期47卷 82-91页

作者： lee Lucy F Avian Disease and Oncology Laboratory East Lansing Ml 48823 USA

DNA sequencing analysis in 38 kd phosphorylated protein (pp38) ORF of Marek's disease viruses (MDV) indicated that all tested 10 virulent strains with different pathotypes had 'A' at base #320 and glutamine at aa#107 while reacted with monoclonal antibody (Mab) H19 in indirect fluorescence antibody test (IFA). However, vaccine strain CVI988 had 'G' at base#320 and arginine at aa#107 instead, when it was negative in IFA with Mab H19. Some strains were also reactive with Mab t65 in IFA while there was 'G' at base #326 and glycine at aa#109, but the other strains, which had 'A' at base #326 and glutamic acid at aa#109, did not react with Mab t65. By comparison of CVI988 to its point mutants CVI/rpp38(AG) and CVI/rpp38(AA) with 1 or 2 base(s) changes at bases #320 and /or #326 of pp38 gene for their reactivity with Mab H19 and t65, it was confirmed that the glutamine at aa#107 and glycine at aa#109 were critical to epitopes H19 and t65 respectively. Immuno-reactions to MDV were compared in SPF chickens inoculated with cloned CVI988 and its mutant CVI/rpp38(AG). It was found that antibody responses to MDV in chickens inoculated with CVI/rpp38(AG) were delayed and significantly lower than that in chickens inoculated with the native CVI988. By differential comparison of antibody titers to different antigens, a third epitope specific to CVI988 and dependent on arginine at aa#107 was suggested to be responsible for the big difference in antibody responses induced by native CVI988 and its mutant.

关键词： Marek's disease virus, pp38 gene, point mutant, epitopes, antibody responses.

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Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-tALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHAtIR t.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and technology Solutions Ho Chi Minh City Open University

this paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. the strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. the curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. the accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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Long-term trends in Extreme temperatures in Hong Kong and Southern China

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Advances in Atmospheric Sciences 2011年第1期28卷 147-157页

作者： t.C.lee E.W.L.GINN Hong Kong Observatory

the observed long-term trends in extreme temperatures in Hong Kong were studied based on the meteorological data recorded at the Hong Kong Observatory Headquarters from 1885-2008. Results show that, over the past 124 years, the extreme daily minimum and maximum temperatures, as well as the length of the warm spell in Hong Kong, exhibit statistically significant long-term rising trends, while the length of the cold spell shows a statistically significant decreasing trend. the time-dependent return period analysis also indicated that the return period for daily minimum temperature at 4°C or lower lengthened considerably from 6 years in 1900 to over 150 years in 2000, while the return periods for daily maximum temperature reaching 35°C or above shortened drastically from 32 years in 1900 to 4.5 years in 2000. Past trends in extreme temperatures from selected weather stations in southern China from 1951-2004 were also assessed. Over 70% of the stations studied yielded a statistically significant rising trend in extreme daily minimum temperature, while the trend for extreme maximum temperatures was found to vary, with no significant trend established for the majority of stations.

关键词： extreme temperature long-term trend Hong Kong southern China

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Extraction of resonance parameters from meson production reaction

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Chinese Physics C 2009年第12期33卷 1140-1145页

作者： t. Sato N. Suzuki t. -S. H. lee Department of Physics Osaka University Toyonaka Osaka 560-0043 Japan Excited Baryon Analysis Center(EBAC) Thomas Jefferson National Accelerator Facility Newport News Virginia 23606 USA Physics Division Argonne National Laboratory Argonne IL 60439 USA

We have developed an analytic continuation method for extracting parameters of nucleon resonances within a Hamiltonian formulation of meson-nucleon reactions. the method was tested for simple solvable models and then applied for our recent coupled channels model （πN, ηN, π△, ρN, and σN ） of the π＊N and γ＊N reactions. the resonance pole positions and their properties are studied for P11and P11 channels.

关键词： baryon resonance meson production reaction resonance pole

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Carbide Formation Process in Directionally Solidified MAR-M247 LC Superalloy

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Journal of Materials Science & technology 1999年第1期15卷 48-52页

作者： Chen, Jian Huang, Baiyun lee, J.H. Choe, S.J. lee, Y.t. Cent S Univ technol Powder Met Res Inst Changsha 410083 Peoples R China Changwon Natl Univ Dept Met & Mat Sci Changwon 641773 South Korea Korea Inst Machinery & Mat Changwon 641010 South Korea

Carbide nucleation, growth and trapping behavior in directionally solidified MAR-M247 LC alloy and the corresponding mechanism have been investigated. Carbide forming element enrichment controls the carbide nucleation and the carbide growth behavior. If the carbide forming element enrichment and the nucleation sites are suitable, carbide nucleation can occur both above and below the liquids temperature. Heterogeneous carbide nucleation is the preferred nucleation mechanism at low carbide forming element enrichment. Carbide growth occurs mainly at inter-secondary gamma dendrite arm area and lower part of the mushy zone. the carbides are subsequently trapped at these positions after growing to a certain size. Some carbides are only partially trapped by the solid-liquid interface and the carbide growth accelerates after being partially trapped. A critical growth rate exists between 2 multiplied by 10** minus **6 m/s and 5 multiplied by 10** minus **6 m/s. the carbide volume fraction decreases in the directionally solidified part at slow growth rate which is caused by the lack of suitable growth site and the low trapping ability of the solid-liquid interface. (Edited author abstract) 16 Refs.

关键词： Nickel alloys

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Ethanol extract from Gynostemma pentaphyllum ameliorates dopaminergic neuronal cell death in transgenic mice expressing mutant A53t human alpha-synuclein

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Neural Regeneration Research 2020年第2期15卷 361-368页

作者： Hyun Jin Park ting ting Zhao Seung Hwan Kim Chong Kil lee Bang Yeon Hwang Kyung Eun lee Myung Koo lee Department of Pharmacy College of PharmacyChungbuk National UniversityCheongjuRepublic of Korea 2Research Center for Bioresource and Health College of PharmacyChungbuk National UniversityCheongjuRepublic of Korea Department of Social Physical Education Songwon UniversityGwangjuRepublic of Korea

Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal models of Parkinson’s disease(PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-and 6-hydroxydopamine. PD patients exhibit multiple symptoms, so PD-related research should combine neurotoxin models with genetic models. In the present study, we investigated the ameliorative effects of GP-EX, including gypenosides, on the cell death of dopaminergic neurons in the midbrain of A53 t α-synuclein transgenic mouse models of PD(A53 t). Both GP-EX and gypenosides at 50 mg/kg per day were orally administered to the A53 t mice for 20 weeks.α-Synuclein-immunopositive cells and α-synuclein phosphorylation were increased in the midbrain of A53 t mice, which was reduced following treatment with GP-EX. treatment with GP-EX modulated the reduced phosphorylation of tyrosine hydroxylase, extracellular signal-regulated kinase(ERK1/2), Bcl-2-associated death promoter(Bad) at Ser112, and c-Jun N-terminal kinase(JNK1/2) due to α-synuclein overexpression. In the A53 t group, GP-EX treatment prolonged the latency of the step-through passive avoidance test and shortened the transfer latency of the elevated plus maze test. Gypenosides treatment exhibited the effects and efficacy similar to those of GP-EX. taken together, GP-EX, including gypenosides, has ameliorative effects on dopaminergic neuronal cell death due to the overexpression of α-synuclein by modulating ERK1/2, Bad at Ser112, and JNK1/2 signaling in the midbrain of A53 t mouse model of PD. Further studies are needed to investigate GP-EX as a treatment for neurodegenerative synucleinopathies, including PD. this study was approved by the Animal Ethics Committee of Chungbuk National University(approval No. CBNUA-956-16-01) on September 21, 2016.

关键词： A53t α-synuclein genetic mice ERK1/2 gynostemma pentaphyllum gypenosides Parkinson’s disease retention transfer latency time

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Patient reported outcome measures in anterior cruciate ligament rupture and reconstruction:the significance of outcome score prediction

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World Journal of Clinical Cases 2022年第30期10卷 10939-10955页

作者： Oday Al-Dadah lee Shepstone Simon t Donell translational and Clinical Research Institute Faculty of Medical SciencesNewcastle UniversityNewcastle-upon-Tyne NE24HHTyne and WearUnited Kingdom Department of trauma and Orthopaedic Surgery South Tyneside District HospitalSouth Shields NE340PLTyne and WearUnited Kingdom Department of Medical Statistics Norwich Medical SchoolUniversity of East AngliaNorwich NR47TJNorfolkUnited Kingdom Norwich Medical School University of East AngliaNorwich NR47TJNorfolkUnited Kingdom

BACKGROUND Numerous anterior cruciate ligament(ACL) clinical outcome measures ***,the result of one score does not equate to the findings of another even when evaluating the same patient *** to investigate if statistically derived formulae can be used to predict the outcome of one knee scoring system when the result of another is known in patients with ACL rupture before and after *** Fifty patients with ACL rupture were evaluated using nine clinical outcome *** included tegner Activity Score,Lysholm Knee Score,Cincinnati Knee Score,International Knee Documentation Committee(IKDC) Objective Knee Score,tapper and Hoover Meniscal Grading Score,IKDC Subjective Knee Score,Knee Outcome Survey-Activities of Daily Living Scale(KOS-ADLS),Short Form-12 Item Health Survey and Knee Injury and Osteoarthritis Outcome *** patients underwent an ACL reconstruction and were reassessed *** the mean total of each of the nine outcome scores appreciably differed from each *** correlations and regressions were found between most of the outcome scores and were stronger *** strongest correlation was found between Cincinnati and KOS-ADLS (r=0.91,Pthe strongest regression formula was also found between Cincinnati and KOS-ADLS (R~2=0.84,Pthe formulae produced from this study can be used to predict the outcome of one knee score when the results of the other are *** formulae could facilitate the conduct of systematic reviews and meta-analysis in studies relating to ACL injuries by allowing the pooling of substantially more data.

关键词： Anterior cruciate ligament Prediction Regression Correlation Patient reported outcome measures Reconstruction Rupture

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Effects of local compositional and structural disorder on vacancy formation in entropy-stabilized oxides from first-principles

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npj Computational Materials 2022年第1期8卷 909-915页

作者： Sieun Chae Logan Williams Jihang lee John t.Heron Emmanouil Kioupakis Department of Materials Science and Engineering University of MichiganAnn ArborMIUSA

Entropic stabilization has evolved into a strategy to create new oxide materials and realize novel functional properties engineered through the alloy *** an atomistic understanding of these properties to enable their design,however,has been challenging due to the local compositional and structural disorder that underlies their fundamental structure-property ***,we combine high-throughput atomistic calculations and linear regression algorithms to investigate the role of local configurational and structural disorder on the thermodynamics of vacancy formation in (MgCoNiCuZn)O-based entropy-stabilized oxides (ESOs) and their influence on the electrical *** find that the cation-vacancy formation energies decrease with increasing local tensile strain caused by the deviation of the bond lengths in ESOs from the equilibrium bond length in the binary *** oxygen-vacancy formation strongly depends on structural distortions associated with the local configuration of chemical *** in ESOs exhibit deep thermodynamic transition levels that inhibit electrical *** applying the charge-neutrality condition,we determine that the equilibrium concentrations of both oxygen and cation vacancies increase with increasing Cu mole *** results demonstrate that tuning the local chemistry and associated structural distortions by varying alloy composition acts an engineering principle that enables controlled defect formation in multi-component alloys.

关键词： alloy structural vacancy

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Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.t.Jeong S.W.lee W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

the superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

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