The Developing Economy and Urban Transportation

Li Junhao 대한교통학회 1998 대한교통학회 기타자료 Vol.1996 No.-

The Developing Economy and Urban Transportation

Li Junhao 대한교통학회 1998 대한교통학회 기타자료 Vol.1998 No.-

Social and economic development needs the support of transportation and communications and in turn the development level of society and economy affects urban traffic demand and determines the investment scale of transportation facilities. In the paper based on the analysis of the evolution of urban transportation in Shanghai in the past ten years and the economic background of that period, the urban transportation in the future development of economy is generally prospected.

Experimental Study on Axial Compression of Concrete with Initial Crack under Hydrostatic Pressure

Junhao Chen,Yanlong Li,Lifeng Wen,Peng Bu,Kangping Li 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.2

The axial compression test of concrete with different initial cracks under hydrostatic pressure is carried out. The fracture propagation is analyzed based on the bearing state as well as the apparent phenomena of the specimens, and the failure modes and morphologies are further elaborated. The test results show that with the increase of the hydrostatic pressure, the peak strength growth rate of different crack dip angle specimens tends to be larger or smaller. The development of the hydrostatic pressure leads to the remarkable growth of the plasticity of initially cracked post-peak plastic specimens. Due to the influence of the crack inclination angle, various rates of variation of the elastic modulus after strain softening are detectable. Under the combinational effects of the crack inclination angle and the hydrostatic pressure, the failure modes of the concrete with different initially inclined cracks are different, leading to fracturing failure and shearing shear failure. The crack propagation morphologies of the initially cracked specimens are also dissimilar. With the increase of the hydrostatic pressure as well as the inclination angle of cracks, the crack propagation pattern gradually changes from I-shaped cracks to II-typed cracks, even I-II composite cracks would appear.

Genome-wide identification of calcium-dependent protein kinases (CDPKs) in pear (Pyrus bretschneideri Rehd) and characterization of their responses to Venturia nashicola infection

Liu Shaohua,Li Junhao,Li Na,Zhou Peng,Li Liulin 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.6

Calcium-dependent protein kinases (CDPKs) play signifi cant roles in response to environmental stresses in plants. However, the CDPK gene family in pear ( Pyrus bretschneideri Rehd) has not been thoroughly explored. In this study, we performed a comprehensive analysis of CDPK family genes in pear, and 30 CDPK genes were identifi ed, unevenly distributed across 13 chromosomes, and predicted to be mainly localized at the plasma membrane. Based on phylogenetic analysis and struc- tural features, the PbCDPKs were classifi ed into four distinct subfamilies. In addition, many putative cis-acting elements responsive to hormones and environmental stresses were identifi ed in the promoter regions. According to RNA-seq data, the majority of PbCDPK genes showed diff erential expression in diff erent pear tissues. After inoculation of plants with the fungus Venturia nashicola , four PbCDPK genes were diff erentially expressed in resistant and susceptible pear cultivars, suggesting that they might play an important role in resistance to the pear scab pathogen. These candidate genes will be subjected to disease resistance and functional analysis in future work. Our results thus provide a genome-wide characterization of CDPK family genes in pear and lay the foundation for further functional analysis.

Cascade hydrogenation of n-C16 to produce jet fuel over tandem catalysts of modified ZSM-22

Yi Li,Junhao Sun,Jie Wei,Chao Mu,Yujun Zhao,Shengping Wang,Xinbin Ma 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

ZSM-22 with one-dimensional straight channels and suitable acid properties is widely applied in theselective hydrocracking of long-chain alkanes to produce middle distillate. In this work, the tandem catalystswith two kinds of modified ZSM-22 were employed in series to optimize the distribution of theproduct in the hydrotreatment of n-C16 to produce jet fuel. The yield of linear alkanes with high carbonnumbers was enhanced over the upstream catalyst bed of Pt/L-HZSM-22 with shielded external acid siteswhile the isomerization with less further cracking occurred over the downstream catalyst bed of Pt/Me-HZSM-22 with introduced mesopores. The tandem catalysts can combine the ability of Pt/L-HZSM-22 toproduce heavy n-alkanes and the stronger isomerization performance of Pt/Me-HZSM-22. The highestyield of jet fuel (23 wt.%) can be obtained over the tandem catalysts instead of any individual catalyst. The strategy of the tandem zeolite has been initially verified and proposed to broaden the investigationperspectives of the oil refinery.

Modeling the Diffusion-Driven Growth of a Pre-Existing Gas Bubble

Anil Kunwar,Haitao Ma,Junhao Sun,Shuang Li,Jiahui Liu 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.5

Finite element method is utilized to solve the diffusion equation and model the diffusion driven growth of a pre-existing spherical gas bubble in molten tin at the solder/substrate interface for reflow time of 120 s and temperature of 250 °C. The gibbs free energy change required for determining the equilibrium concentration at liquid solder/gas bubble boundary was calculated using the thermodynamic polynomial coefficients. The rate of change of radius, as function of concentration flux, is calculated using the lagrangian mesh update methodology. With an initial diameter of 20 μm, the bubble growth is calculated as a function of contact angle. When the wetting angle is varied from a value of 30° to 135°, the numerical calculation has yielded the final sizes for the bubble to change from 62.87 μm to 82.8 μm respectively. The effect of wetting transition in the growth of bubble was studied by the in-situ observation of bubble dynamics through synchrotron radiation imaging technique. The scanning electron microscopy images of the morphologies of intermetallic compounds influenced by growing bubble in Sn/Cu solder joint and bubble pictures obtained through synchrotron radiation are utilized to get the experimental size of the bubble. The mean experimental bubble diameter has been obtained as 76.39 μm. The growing bubble inhibits the growth of intermetallic compound at its vicinity and thereby reduces the strength of solder joints.

Thin-film electronics based on all-2D van der Waals heterostructures

Liu Xinling,Yang Xiaomin,Sang Weihui,Huang Hai,Li Wenwu,Lin Yen-Fu,Chu Junhao 한국정보디스플레이학회 2021 Journal of information display Vol.22 No.4

Two-dimensional (2D) layered materials including metal, semiconductor, and insulator have received extensive attention in recent years. The weak van-der-Waals (vdW) interactions between 2D materials layers enable them to isolate monolayers and restack into artificial 2D vdW heterostructures in the desired sequence. These assembled all-2D vdW heterostructures are promising platforms for fabricating next-generation electronics as well as optoelectronics. In particular, the all-2D vdW heterostructure devices composed entirely of 2D layered material have received extensive attention due to their natural thickness, atomically sharp heterointerfaces, and excellent mechanical flexibility. Herein, we firstly introduce 2D vdW heterostructures and their preparation methods. Secondly, the recent progress of field-effect transistors (FETs) and photodetectors based on all-2D vdW heterostructures are summarized. Finally, we discuss some challenges of all-2D vdW heterostructure-based devices for practical applications and offer personal perspectives toward the future development of thin-film electronics.

Reliable Mobility Evaluation of Organic Field-Effect Transistors With Different Contact Metals

Huang, Fanming,Liu, Ao,Zhu, Huihui,Xu, Yong,Balestra, Francis,Ghibaudo, Gerard,Noh, Yong-Young,Chu, Junhao,Li, Wenwu IEEE 2019 IEEE electron device letters Vol.40 No.4

<P>The reliability of mobility evaluation of organic field-effect transistors (OFETs) is a serious issue because numerous overestimated and underestimated mobilities have been reported recently. A reliable approach to accurately evaluate the OFET mobility is therefore highly desirable. Here, in this letter, two commonly employed methods and the Y function method (YFM) were used to extract the mobilities of indacenodithiophene-co-benzothiadiazole (IDT-BT) OFETs with four different contact metals. The mobilities extracted by the commonly used methods varied greatly with the contact metal and channel length, whereas those extracted by the YFM were very stable and approached the intrinsic mobility of IDT-BT. Our results show that YFM is a precise approach that can be widely used to evaluate the OFET mobility.</P>