Development of the Diffusive Gradients in Thin-Films (dgt) Technique to Measure Plant-Available Potassium in Soils

Yulin Zhang,Sean Mason,Ann Mcneill,Michael Mclaughlin,Fien Degryse,Gunasekhar Nachimuthu 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

CFD Numerical Simulation of Wind Field and Vehicle Aerodynamic Characteristics on Truss Bridge Deck under Crosswind

Mingjin Zhang,Jinxiang Zhang,Junting Long,Yongle Li,Yulin Zou,Dianguo Yin 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.12

Due to the complexity and changeability of the wind field in deep-cut gorges, the vehicles on the bridge deck are easily affected by a strong crosswind. Thus, to accurately evaluate the wind field characteristics of a suspension bridge deck, the wind profiles of wind speed and angle of attack (AoA) and the vehicle aerodynamic parameters were investigated by the CFD. The results show that the shape of wind speed profile is mainly controlled by the AoA but less affected by the Reynolds number. The main girder's shielding effect can accelerate the local wind field, and the closer to the windward lane, the less the interference; thus, a suitable location of measuring points to represent the incoming flow is found. Furthermore, the equivalent wind speed based on the equivalent side force is generally larger than the value based on the rolling moment, and the responding value is greatly affected by the AoA. In addition, the vortex is a time-dependent phenomenon, the averaged flow field produced less force in the wake, but the high local wind speed variations may affect the traffic unfavorably. The results provide an essential reference significance for studying the local wind field characteristics of the bridge deck.

An analytical solution to the vibration characteristics for continuous girder bridge-track coupling system and its application

Yulin Feng,Lizhong Jiang,Wangbao Zhou,Yuntai Zhang,Xiang Liu 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.5

To study the vibration characteristics of a high-speed railway continuous girder bridge-track coupling system (HSRCBT), a coupling vibration analysis model of an m-span continuous girder bridge-subgrade-track system with n-span approach bridge was established. The model was based on the energy and its variational method, where both the interlaminar slip and shear deformation effects were considered. In addition, the free vibration equations and natural boundary conditions of the HSRCBT were derived. Further, according to the coordination principle of deformation and mechanics, an analytical method for calculating the natural vibration frequencies of the HSRCBT was obtained. Three typical bridge-subgrade-track coupling systems of high-speed railway were taken and the results of finite element analysis were compared to those of the analytical method. The errors between the simulation results and calculated values of the analytical method were less than 3%, thus verifying the analytical method proposed in this paper. Finally, the analytical method was used to investigate the influence of the number of the approach bridge spans and the interlaminar stiffness on the natural vibration characteristics of the HSRCBT based on the degree of sensitivity. The results suggest the approach bridges have a critical number of spans and in general, the precision requirements of the analysis could be met by using 6-span approach bridges. The interlaminar vertical compressive stiffness has very little influence on the low-order natural vibration frequency of HSRCBT, but does have a significant influence on higher-order natural vibration frequency. As the interlaminar vertical compressive stiffness increases, the degree of sensitivity to interlaminar stiffness of each of the HSRCBT natural vibration characteristics decrease and gradually approach zero.

Comparison of long-term behavior between prestressed concrete and corrugated steel web bridges

Yulin Zhan,Fang Liu,Zhongguo John Ma,Zhiqiang Zhang,Zengqiang Duan,Ruinian Song 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.6

Prestressed concrete (PC) bridges using corrugated steel webbing have emerged as one of the most promising forms of steel-concrete composite bridge. However, their long-term behavior is not well understood, especially in the case of largespan bridges. In order to study the time-dependent performance, a large three-span PC bridge with corrugated steel webbing was compared to a similar conventional PC bridge to examine their respective time-dependent characteristics. In addition, a threedimensional finite element method with step-by-step time integration that takes into account cantilever construction procedures was used to predict long-term behaviors such as deflection, stress distribution and prestressing loss. These predictions were based upon four well-established empirical creep prediction models. PC bridges with a corrugated steel web were observed to have a better long-term performance relative to conventional PC bridges. In particular, it is noted that the pre-cambering for PC bridges with a corrugated steel web could be smaller than that of conventional PC bridges. The ratio of side-to-mid span has great influence on the long-term deformation of PC bridges with a corrugated steel web, and it is suggested that the design value should be between 0.4 and 0.6. However, the different creep prediction models still showed a weak homogeneity, thus, the further experimental research and the development of health monitoring systems are required to further progress our understanding of the long-term behavior of PC bridges with corrugated steel webbing.

ARPES study of the epitaxially grown topological crystalline insulator SnTe(111)

Zhang, Yi,Liu, Zhongkai,Zhou, Bo,Kim, Yeongkwan,Yang, Lexian,Ryu, Hyejin,Hwang, Choongyu,Chen, Yulin,Hussain, Zahid,Shen, Zhi-Xun,Mo, Sung-Kwan Elsevier 2017 Journal of electron spectroscopy and related pheno Vol.219 No.-

<P><B>Abstract</B></P> <P>SnTe is a prototypical topological crystalline insulator, in which the gapless surface state is protected by a crystal symmetry. The hallmark of the topological properties in SnTe is the Dirac cones projected to the surfaces with mirror symmetry, stemming from the band inversion near the L points of its bulk Brillouin zone, which can be measured by angle-resolved photoemission. We have obtained the (111) surface of SnTe film by molecular beam epitaxy on BaF<SUB>2</SUB>(111) substrate. Photon-energy-dependence of <I>in situ</I> angle-resolved photoemission, covering multiple Brillouin zones in the direction perpendicular to the (111) surface, demonstrate the projected Dirac cones at the Γ ¯ and M ¯ points of the surface Brillouin zone. In addition, we observe a Dirac-cone-like band structure at the Γ point of the bulk Brillouin zone, whose Dirac energy is largely different from those at the Γ ¯ and M ¯ points.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Topological crystalline insulator SnTe(111) thin film was grown on BaF<SUB>2</SUB>(111) substrate by using molecular beam epitaxy. </LI> <LI> The electronic structures of SnTe(111) with surface Dirac cones were studied by a wide-range photon-energy-dependent angle-resolved photoemission spectroscopy. </LI> <LI> A Dirac-cone-like band structure was observed at the Γ point of the bulk Brillouin zone of SnTe(111). </LI> </UL> </P>

Lifshitz Transitions Induced by Temperature and Surface Doping in Type-II Weyl Semimetal Candidate T_<i>d</i> -WTe₂

Zhang, Qihang,Liu, Zhongkai,Sun, Yan,Yang, Haifeng,Jiang, Juan,Mo, Sung-Kwan,Hussain, Zahid,Qian, Xiaofeng,Fu, Liang,Yao, Shuhua,Lu, Minghui,Felser, Claudia,Yan, Binghai,Chen, Yulin,Yang, Lexian Wiley (John WileySons) 2017 Physica Status Solidi. Rapid Research Letters Vol.11 No.12

Adaptive flow optimization of a turbocharger compressor to improve engine low speed performance

Yangjun Zhang,Chenfang Wang,Zheng Xinqian,Weilin Zhuge,Yulin Wu,Jianzhong Xu 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

To improve the engine overall performance, an adaptive flow optimization procedure is proposed in this paper to synthesize turbocharger compressor optimum designs. Two objective functions are involved in the adaptive optimization. They are the traditional compressor design and the compressor design with consideration of improving engine overall performance. The two-step decomposition approach is chosen to generate optimum designs. The optimized designs not only satisfy turbomachinery and engine constraints but also have optimum objective function values in the two fields. Performance sensitivity analysis of compressor main design variables is performed for the flow optimization design process. A centrifugal compressor is redesigned for a turbocharged gasoline engine, as an example, based on the adaptive flow optimization process. The calculating results show a more than 5% increase of isentropic efficiency in comparison with the base line compressor, resulting in a more than 19% increase of engine torque at low speed conditions.

Critical coupling span number in high-speed railway simply supported beam bridge

Yuntai Zhang,Lizhong Jiang,Wang-Bao Zhou,Yulin Feng,Xiang Liu,Zhipeng Lai 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.1

In long-distance railways, some particular spans of high-speed railway simply supported beam bridges (HSRSBs) are commonly selected as the target structure. The target structure is the part of interest for the study and intended to be analyzed. Due to longitudinal constraints of the track system, the target structure is tightly coupled with other spans within certain range, and is affected by the coupled spans under longitudinal earthquake condition. A massive amount of time-consuming computation is required to determine the coupling span number using current finite element models. In an effort to overcome this challenge, an equivalent method for the longitudinal constraints of the track system is proposed, which greatly reduces the complexity of finite element model while retaining calculation precision. The coupling span number was determined by seismic analyses of a large number of cases using equivalent finite element models. Moreover, the influence of pier height and bottom pier stiffness on coupling span number was studied. Based on the relationship between the equivalent boundary sensitivity critical point and coupling span number, a method to quickly obtain coupling span number of the target structure in arbitrary HSRSB was constructed.

Effect of Phosphodiesterase-5 Inhibitors on the Treatment of Male Infertility: A Systematic Review and Meta-Analysis

Dong Liang,Zhang Xiaojin,Yan Xuhong,Shen Yifeng,Li Yulin,Yu Xujun 대한남성과학회 2021 The World Journal of Men's Health Vol.39 No.4

Purpose: Male infertility is a worldwide problem with limitations in the treatment. Phosphodiesterase-5 inhibitors (PDE5is) is the first choice for the treatment of erectile dysfunction, more and more studies show that it has a certain effect on male infertility in recent years. But there was currently no high quality of systematic review to evaluate the effects of PDE5is on semen quality. Materials and Methods: We retrieved the electronic databases of MEDLINE, PubMed, Web of Science, EMBASE, etc. Related randomized controlled trials (RCTs) were collected and selected up to May 20, 2020. We have searched literature with terms “male infertility”, “phosphodiesterase-5 inhibitors”, “PDE5i”, “Tadalafil”, “Sildenafil”, “Vardenafil”, “Udenafil”, “Avanafil”, “semen”, and “sperm”. Mean value and its standard deviation were used to perform quantitative analysis. All statistical analyses were conducted by RevMan 5.3 and Stata software. Results: There were a total of 1,121 participants in the nine included studies. There was a statistically significant improvement treated with PDE5is compared with sham therapy, which including sperm concentration (mean difference [MD]=1.96, 95% confidence interval [CI]=1.70–2.21, p<0.001; MD=3.22, 95% CI=1.96–4.48, p<0.001), straight progressive motility (%) Grade A (MD=3.71, 95% CI=2.21–5.20, p<0.001), sperm motility (MD=8.09, 95% CI=7.83–8.36, p<0.001), morphologically normal spermatozoa (%) (MD=0.67, 95% CI=0.20–1.15, p=0.005; MD=1.27, 95% CI=0.02–2.52, p=0.05), sperm abnormalities (%) (MD=-0.64, 95% CI=-0.81–-0.47, p<0.001), and progressive motile sperm (MD=5.34, 95% CI=3.87–6.81, p<0.001). Conclusions: In this meta-analysis of nine RCTs, treatment with PDE5is could improve some indicators of male sperm.

Modification of hollow BiOCl/TiO2 nanotubes with phosphoric acid to enhance their photocatalytic performance

Guozhe Sui,Yulin Zhang,Jinlong Li,Yan Zhuang,Dongxuan Guo,Ze Luo,Rongping Xu,Shuang Liang,Hong Yao,Chao Wang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.4

Organic pollutants in dyed wastewater are hazardous to human health and the environment. The photocatalyticdegradation of pollutants is considered a green treatment with significant social and environmental benefits. Inthis study, hollow BiOCl/TiO2 nanotubes with open pores at both ends, prepared by hydrothermal synthesis, weremodified using phosphoric acid to promote photoelectron transfer. The hollow nanotubes offer an increased numberof electroactive sites, which enhances the photoelectric transfer efficiency and reduces the electron-hole recombinationrate. The modification by H3PO4 significantly optimized the photocatalytic activity of the nanotubes. The results showthat the H3PO4 modified hollow BiOCl/TiO2 (molar ratio of BiOCl to TiO2 is 0.8) nanotubes exhibited the most efficientphotocatalytic performance toward rhodamine B (RhB) with a photodegradation efficiency of up to 98.8% undervisible-light illumination. These nanotubes have broad application prospects for the effective removal of organic pollutantsfrom wastewater and can potentially inform future research on photocatalysts.