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New Adjustment Method for the Width of Monorail Beams on Curve
Eryu Zhu,Hongliang Wang,Lei Wang,Yujie Li,Li Zhu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5
A new method to improve the passing performance of monorail train driving on a curve by adjusting the width of monorail beams is proposed. Equations for deformation of steering wheel and stabilizing wheel with respect to the contact relationship between monorail beams and trains are derived by geometric analysis. Then two kinds of adjustment schemes are proposed, equal width adjustment method and unequal width adjustment method. A curved guide way of radius 100 m is taken for the example to verify the validity of the improved method by comparing the tire deformation of monorail train driving on the beams before and after the adjustment of width. The results show that the improved adjustment method for the width of monorail beam is efficient to reduce tire deformation when the monorail train travels on a curve. For the guide way of radius 100 m, width of the beams should be reduced by 7 mm when the equal width adjustment method is adopted. When the unequal width adjustment method is adopted, the width of monorail beams at the position of steering wheel carriageway and stabilizing wheel carriageway should be reduced by 10 mm and 5 mm, respectively.
AN IMPROVED METHOD FOR TRANSFERRING GRAPHENE GROWN BY CHEMICAL VAPOR DEPOSITION
YUJIE REN,CHAOFU ZHU,WEIWEI CAI,HUIFENG LI,YUFENG HAO,YAPING WU,SHANSHAN CHEN,QINGZHI WU,RICHARD D. PINER,RODNEY S. RUOFF 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2012 NANO Vol.7 No.1
In this paper, we report an improved transfer of graphene by directly picking up the graphene with target substrates and the comparison of such transferred graphene samples with other graphene samples transferred by the commonly used "PMMA-based transfer" method. Raman spectroscopy studies show that this "direct transfer method" does not degrade the graphene structure and field effect transistor measurements show that it does not introduce any extra doping in graphene; in contrast, PMMA-based transfer samples have strong n-type doping. We also find that graphene samples achieved by this direct transfer method show higher mobility than graphene obtained from the PMMA-based transfer method.
Zhu Yu-Hang,Yan Wu,Hao Zhang,Yanfei Zhao,Yule Ren,Wei Hu,Pan Li,Huiyi Wang,Ying Wang,Boda Zhang,Yujie Wang,Hongwen Yuan,Jiping Zhang,Wenqiang Li,Yufang Zhao,Jie Zhao,Yedong Shi,Yanye Shu,Xiao Zhang,Ya 한국한의학연구원 2022 Integrative Medicine Research Vol.11 No.4
Background With the increasing popularity of traditional Chinese medicine (TCM) by the global community, how to teach basic knowledge of TCM to international students and improve the teaching quality are important issues for teachers of TCM. The present study was to analyze the perceptions from both students and teachers on how to improve TCM learning internationally. Methods A cross-sectional national survey was conducted at 23 universities/colleges across China. A structured, self-reported on-line questionnaire was administered to 34 Chinese teachers who taught TCM course in English and to 1016 international undergraduates who were enrolled in the TCM course in China between 2017 and 2021. Results Thirty-three (97.1%) teachers and 900 (88.6%) undergraduates agreed Chinese culture should be fully integrated into TCM courses. All teachers and 944 (92.9%) undergraduates thought that TCM had important significance in the clinical practice. All teachers and 995 (97.9%) undergraduates agreed that modern research of TCM is valuable. Thirty-three (97.1%) teachers and 959 (94.4%) undergraduates thought comparing traditional medicine in different countries with TCM can help the students better understand TCM. Thirty-two (94.1%) teachers and 962 (94.7%) undergraduates agreed on the use of practical teaching method with case reports. From the perceptions of the undergraduates, the top three beneficial learning styles were practice (34.3%), teacher's lectures (32.5%), case studies (10.4%). The first choice of learning mode was attending to face-to-face teaching (82.3%). The top three interesting contents were acupuncture (75.5%), Chinese herbal medicine (63.8%), and massage (55.0%). Conclusion To improve TCM learning among international undergraduates majoring in conventional medicine, integration of Chinese culture into TCM course, comparison of traditional medicine in different countries with TCM, application of the teaching method with case reports, and emphasization of clinical practice as well as modern research on TCM should be fully considered.
Yujie Yang,Xiansong Liu,Shuangjiu Feng,Qingrong Lv,Xucai Kan,Ruiwei Zhu 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.3
Praseodymium substituted strontium W-type hexaferrites Sr1-xPrxZn0.8Co1.2Fe16O27 (0.00 ≤ x ≤ 0.40) were prepared via theconventional ceramic technique. XRD analysis of W-type hexaferrites with Pr content (x) of 0.00 ≤ x ≤ 0.24 shows the single Wtypehexaferrite phase. However, for the W-type hexaferrites with Pr content (x) ≥ 0.32, the impurity phase (α-Fe2O3) is detected. FE-SEM images show that the grains are platelet-like shapes. The saturation magnetization (Ms), remanent magnetization (Mr)and magneton number (nB) first increase with Pr content (x) from 0.00 to 0.16, and then decrease when Pr content (x) ≥ 0.16. The Mr/Ms ratio, magnetic anisotropy field (Ha), coercivity (Hc) and maximum energy product [(BH)max] increase with Pr content(x) from 0.00 to 0.40. While the first anisotropy constant (K1) increases with Pr content (x) from 0.00 to 0.16, and then decreaseswhen Pr content (x) ≥ 0.16. The DC electrical resistivity (ρ) decreases with Pr content (x) from 0.00 to 0.40.
Yujie Li,Yu Zhu,Ming Zhang,Xin Li,Leijie Wang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.3
More lightweight structure and higher control bandwidth are highly desirable in next-generation motion stages, satisfying the continuously increasing requirements in throughput and accuracy. However, these lead to more severe flexible deformation, causing that the estimation accuracy of the generalized displacements of a point of interest (POI) cannot be guaranteed under the rigid-body assumption. In this paper, a method for estimating the generalized displacement of the POI using critical modes is proposed. This method can realize a more accurate estimation under the limited measurement points. In this method, since the number of measurement points is limited, the selection criterion of the critical modes is firstly proposed for the over-actuator system; then, with regard to the estimation accuracy, the influences of the measurement layout and the residual modes on the estimation matrix are analyzed mathematically, and a performance measure is proposed for evaluating this method from the perspective of system control. In the verification section, the validity of the estimation method is demonstrated through numerical simulation and an experiment on a representative but straightforward case using a plate structure.
Interfacial performance enhancement of carbon fiber/epoxy composites by a twostep surface treatment
Jian Shi,Yuji Yamamoto,Mamoru Mizuno,Chunhong Zhu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1
Carbon fiber-reinforced polymer composites (CFRPs) have many features, such as lightweight, high specific strength, and excellent chemical resistance. However, the adhesion at the interface of the CFRPs, which are composed of fiber and resin, is poor. Thus, delamination and interfacial peeling occur, and the mechanical properties, such as intrinsic strength and rigidity, decrease. Fiber surface modification by plasma and silane coupling treatments has attracted much attention to improve these properties. In this study, argon and oxygen mixed gas plasma treatment was used as pretreatment to introduce hydroxyl group on the fiber surface. This method was utilized to improve the adhesion between the fiber and resin. A silane coupling treatment was conducted to bond the carbon fiber and epoxy resin by chemical covalent bonding. The effect of silane coupling treatment on the interfacial property of CFRPs was investigated. Elemental analysis of the surface modified carbon fiber was explored through energy dispersive X-ray spectrometry. The functional groups of different carbon fiber surfaces were analyzed through X-ray photoelectron spectroscopy. The wettability of the treated carbon fiber was examined with a contact angle meter. The interlaminar shear strength was determined with a short beam method.
Property Assessment of High-Performance Concrete Containing Three Types of Fibers
Hua Huang,Yujie Yuan,Wei Zhang,Liang Zhu 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.6
This study investigated the mechanical properties and the effects of the volume fraction for carbon fibers (CF-VF), polypropylene fibers (PPF-VF) and aramid fibers (AF-VF) with a fixed aspect ratio of 650 for the carbon fibers, 400 for the polypropylene fibers and 900 for the aramid fibers in hybrid fiber-reinforced concrete (HFRC). Furthermore, compressive, splitting tensile and flexural tensile tests were carried out to obtain the optimal total volume fraction for the three types of fibers, as well as the optimal ratio between the CF-VF, PPF-VF and AF-VF. In addition, stress-strain curves of normal concrete and HFRC were examined to explore the whole mechanical process. The results indicated the CF-VF, PPF-VF and AF-VF have a significant effect on the tensile and flexural strengths of HFRC. The HFRC with a fiber additional ratio of 25:50:25 had the best hybrid effect. Moreover, a calculation method based on the compressive strength of normal concrete and HFRC and the volume fraction is proposed to calculate the strength of HFRC in engineering as a reference. Besides, a uniaxial compression constitutive mathematical model of normal concrete and HFRC is established.