An integrated optimal design of energy dissipation structures under wind loads considering SSI effect

Xuefei Zhao,Han Jiang,Shuguang Wang 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.2

This paper provides a simple numerical method to determine the optimal parameters of tuned mass damper (TMD) and viscoelastic dampers (VEDs) in frame structure for wind vibration control considering the soil-structure interation (SSI) effect in frequency domain. Firstly, the numerical model of frame structure equipped with TMD and VEDs considering SSI effect is established in frequency domain. Then, the genetic algorithm (GA) is applied to obtain the optimal parameters of VEDs and TMD. The optimization process is demonstrated by a 20-storey frame structure supported by pile group for different soil conditions. Two wind resistant systems are considered in the analysis, the Structure-TMD system and the Structure-TMD-VEDs system. The example proves that this method can quickly determine the optimal parameters of energy dissipation devices compared with the traditional finite element method, thus is practically valuable.

중국인 학습자를 위한 보조사 ‘까지, 조차, 마저’의 교육 방안 연구

조학비(Zhao Xuefei),박덕유(Park deokyu) 학습자중심교과교육학회 2021 학습자중심교과교육연구 Vol.21 No.23

목적 본 연구는 한국어 보조사 중에 유사문법 형태인 ‘까지, 조차, 마저’의 의미⋅통사적 특성을 고찰하고 오류 양상을 분석하여 중국인 학습자들에게 효과적인 교육 방안을 제시하는 데에 있다. 방법 한국어 보조사 ‘까지, 마저, 조차’는 여러 가지 의미와 용법이 있으므로 본고에서는 이에 대한 의미적⋅통사적 특성을 고찰한 다음에 한국과 중국에서 간행된 한국어 교재에 제시된 내용을 대비하고 분석하여 장단점을 제시하였다. 그리고 중국인 학습자를 대상으로 ‘까지, 조차, 마저’의 오류 양상을 분석하여 그 결과를 바탕으로 오류 원인을 밝힘으로써 효율적인 교육 방안을 고찰하였다. 결과 ‘까지, 조차, 마저’는 비슷한 의미를 가지고 있어 유사한 환경에서 서로 교체해서 사용할 수도 있지만, 각각의 통사적 사용에서 미세한 차이가 있다. ‘까지’는 어떤 일이나 상태 따위에 관련되는 범위의 끝임을 나타내는 것이고, ‘조차’는 그 상황 이상의 것이 더해지는 의미를 수반한다. 그리고 ‘마저’는 어떠한 것에 더해서 그보다 더 나쁘거나 다른 것을 덧붙인다는 의미를 갖는다. 이중 ‘까지’는 ‘마저’보다는 더 자유롭게 사용돼 의문대명사와 공기할 수 있지만, ‘조차’는 명령문과 청유문에서 사용할 수 없다. 결론 ‘까지, 조차, 마저’의 관계를 명확하게 파악하기 위해 교재에서 설명이 충분하지 않은 부분과 오류를 많이 범하는 원인을 고찰하여 이에 대한 교수⋅학습 방안을 세 보조사의 비교 분석을 통해 기술하였다. Objectives The purpose of this study is to consider the semantic and syntactic characteristics of ‘kkaji, jocha, majeo’, a form of similar grammar among Korean language assistants, and to present effective educational methods for Chinese learners by analyzing error patterns. Methods The Korean auxiliary postpositional particle ‘kkaji, jocha, majeo’ have many meanings and uses, so this ointment considered the semantic and syntactic characteristics of them and prepared and analyzed the contents presented in Korean textbooks published in Korea and China. In addition, efficient education methods were considered by analyzing the error patterns of ‘kkaji, jocha, majeo’ for Chinese learners and identifying the cause of the error based on the results. Results ‘kkaji, jocha, majeo’ has a similar meaning and can be used in a similar environment by replacing each other, but there is a fine difference in each syntactic use. “kkaji” indicates the end of a range related to a task or condition, and “jocha” entails more than that situation. And ‘majeo’ means adding something worse or something else. Among them, “kkaji” is more freely used than “majeo” so it can be used with questionable pronouns and air, but “jocha” cannot be used in command and request sentence. Conclusions In order to clearly understand the relationship between ‘kkaji, jocha, majeo’, the teaching and learning methods were described through comparative analysis of the three auxiliary postpositional parties by considering the insufficient explanation in the textbook and the causes of many errors.

Pyrolysis kinetics and microstructure of thermal conversion products on toluene soluble component from two kinds of modified pitch

Yaming Zhu,Xuefei Zhao,Lijuan Gao,Junxia Cheng 한국탄소학회 2018 Carbon Letters Vol.28 No.-

Modified pitch A (MPA) and modified pitch B (MPB) were prepared by oxidative polymerization and thermal polycondensation reaction with refined pitch as the raw material, respectively. The toluene soluble components (TS-1 and TS-2) were obtained by solvent extraction from MPA and MPB, separately. The Flynn-Wall-Ozawa method and Kissinger-Akahira- Sunose method were used to calculate the pyrolysis activation energy of TS. The Satava- Sestak method was used to investigate the pyrolysis kinetic parameters of TS. Moreover, the optical microstructure of the thermal conversion products (TS-1-P and TS-2-P) by calcination shows that TS-1-P has more contents of mosaic structure and lower contents of fine fiber structure than TS-2-P. The research result obtained by a combination of X-ray diffraction and the curve-fitting method revealed that the ratios of ordered carbon crystallite (Ig) in TS-1-P and TS-2-P were 0.3793 and 0.4417, respectively. The distributions of carbon crystallite on TS-1-P and TS-2-P were calculated by Raman spectrum and curve-fitting analysis. They show that the thermal conversion product of TS-2 has a better graphite crystallite structure than TS-1.

Changes in structure of coal liquefied pitch during liquid‑phase carbonization process

Yaming Zhu,Xuefei Zhao,Ji Yuan,Chunlei Zhao,Chaoshuai Hu 한국탄소학회 2019 Carbon Letters Vol.29 No.1

residue as the raw material. As one of the preconceived raw material to produce high-quality coal-based carbon material, the changes of structure of CLP during liquid-phase carbonization process have been detailed investigated in this study. Actually, FTIR and curve-fitted method were used to quantitative analyze the aromaticity index (Iar), the ratio of CH3/ CH2, and basic functional groups (C=C, C=O, and C–O) of CLP and its liquid-phase carbonization products. Polarizing microscope, XRD and curve-fitted methods were used to characterize the microstructures of CLP and derived products. The results show that, branched chain and C=O group are the active reaction point in liquid-phase carbonization process. What’s more, 450 °C is a critical temperature point on the severe thermal polycondensation of CLP. The XRD and curve-fitted analysis of CLP and its liquid-phase carbonization products shows that, the stacking height (Lc), parallel layers (N), and the numbers of aromatic ring in each layer (n) are gradually larger with the improve of liquid-phase carbonization temperature.

Electrochemical performance of porous carbons derived from needle coke with different textures for supercapacitor electrode materials

Junxia Cheng,Zhenjie Lu,Xuefei Zhao,Xingxing Chen,Yaming Zhu,Hongyu Chu 한국탄소학회 2021 Carbon Letters Vol.31 No.1

The porous carbons with high specific surface area and excellent electrochemical properties were prepared using three types of green needle coke as raw materials. Electrochemical performances of the porous carbons derived from different microstructure green needle coke were investigated. The XRD and Raman spectra demonstrated that the content of the ordered carbon microcrystals were decreased and the content of amorphous and cross-linked structure were increased in the porous carbons with comparison to the raw materials. The results of N2 adsorption–desorption analysis verified that the content of ordered microcrystalline structure in the raw materials evidently influence the specific surface area and pore size distribution of the porous carbons. The porous carbon with 1665 m2 g?1 specific surface area and 2.89 nm average pore size has shown that the specific capacitance was 288 F g?1 at the current density 1 A g?1. Furthermore, the capacity retention was 94.93% and the Coulombic efficiency was 92.87% after 5000 charge/discharge cycles.

Evaluation of Curtain Grouting Efficiency by Cloud Model - based Fuzzy Comprehensive Evaluation Method

Yushan Zhu,Xiaoling Wang,Shaohui Deng,Mengqi Zhao,Xuefei Ao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

Because of the concealment and uncertainty of dam foundation grouting, the accurate evaluation of the quality of grouting construction is a major concern. Most of the previous studies pertaining to the assessment of grouting efficiency only take a single factor into account, and only a few efforts have been devoted to the comprehensive evaluation of grouting efficiency, which fail to consider the fuzziness problems caused by the complex relationships among indicators as well as the randomness problems caused by subjective consciousness. Therefore, the curtain grouting efficiency evaluation method considering the uncertainty in evaluation process is proposed which includes three main parts: 1) Based on conventional evaluation indicators of grouting efficiency, where groutability is introduced as a new indicator; 2) a fuzzy comprehensive evaluation method based on cloud model is developed, by which the fuzziness and randomness in assessment are organically combined; and 3) the fuzzy entropy was calculated for indicating the complexity of grouting efficiency level. Then, the proposed method is used to assess efficiency of the curtain grouting for a hydropower station in China, and compared with three other methods. The outcomes display the consistency, representativeness, robustness and superiority of this evaluation method, which make the evaluation results more scientific and objective.