Insight into Fundamental Rules of Phenylenediamines Selective Monoacylation by the Comparisons of Kinetic Characteristics in Microreactor

Xu Qilin,Liu Ji Ming,Yao Hongmiao,Zhao Jinyang,Wang Zhikuo,Liu Junli,Zhou Jiadi,Yu Zhiqun,Su Weike 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.10

In this paper, the kinetics of acylation reaction of o-phenylenediamine/p-phenylenediamine and benzoic anhydride were determined in microreactors, respectively. A kinetic model was established, all kinetic parameters including reaction orders, reaction rate constants, pre-exponential factors, and activation energies were acquired. Validation experiments showed experimental data fit well with calculated data at different reactant concentrations and residence times. The comparisons of the reaction rate constants and activation energies were summarized to show the difference of chemical reactivities of phenylenediamines. According to the calculation of the kinetic model, the optimized reaction conditions were listed to meet the monoacylation selectivity equal to 97.0%.

Experimental and Theoretical Study of the Torsional Mechanism of a Hybrid FRP-aluminum Triangular Deck-truss Structure

Dongdong Zhang,Qilin Zhao,Fei Li,Feng Li 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.6

This paper investigates the torsional mechanism of a hybrid FRP-aluminum triangular deck-truss structure composed of modular structural units. A pure torsion test was conducted on a 6-m cantilever specimen to characterize the structural responses. Based on the experimental results and structural layout, a simplified analytical model is established to predict the torsional stiffness of the hybrid triangular deck-truss structure. The derivation procedures and formulae are experimentally calibrated, finding that the formulae can be conveniently used with satisfactory accuracy. It is ultimately confirmed that the torsional center of the entire triangular truss collocates with the center of the orthotropic deck. The external torsional moment is primarily resisted by the FRP lower chords and the aluminum longitudinal beams, particularly for the FRP lower chords which should be given a great consideration in the torsion design.

Experimental investigation of novel pre-tightened teeth connection technique for composite tube

Fei Li,Qilin Zhao,Haosen Chen,Longxing Xu 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.2

A new composite tube connection method called the pre-tightened teeth connection technique is proposed to improve the composite tube connection efficiency. This paper first introduces the manufacturing process of the proposed technique. It then outlines how the mechanical properties of this technology were tested using four test groups. The factors that influence the load-bearing capacity and damage model of the connection were analyzed, and finally, the transfer load mechanism was investigated. The following conclusions can be obtained from the research results. (1) The new technique improves the compressive connection efficiency by a maximum of 79%, with the efficiency exceeding that of adhesive connections of the same thickness. (2) Changing the depth of teeth results in two types of damage: local compressive damage and shear damage. The bearing capacity can be improved by increasing the depth, length, and number of teeth as well as the pretightening force. (3) The capacity of the technique to transfer high loads is a result of both the relatively high interlaminar shear strength of the pultruded composite and the interlaminar shear strength increase provided by the pre-tightening force. The proposed technique shows favorable mechanical properties, and therefore, it can be extensively applied in the engineering field.

Experimental and theoretical research on the compression performance of CFRP sheet confined GFRP short pole

Li Chen,Qilin Zhao,Kebin Jiang 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.2

The axial compressive strength of unidirectional FRP is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. In order to restrain the lateral expansion and splitting of GFRP, and accordingly heighten its axial compressive bearing capacity, a project that to confine GFRP pole with surrounding CFRP sheet is suggested in the present study. The Experiment on the CFRP sheet confined GFRP poles showed that a combined structure of high bearing capacity was attained. Basing on the experiment research a theoretical iterative calculation approach is suggested to predict the ultimate axial compressive stress of the combined structure, and the predicted results agree well with the experimental results. Then the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure are also analyzed basing on this approach.

디지털 영화시대의 심미기대와 심미체험의 변화에 관한 연구 - 발터 벤야민 충격효과(Schockwirkung)를 중심으로

자오원장(Wenjiang Zhao),최동혁(Donghyuk Choi),서치린(Qilin She) 동국대학교 영상문화콘텐츠연구원 2021 영상문화콘텐츠연구 Vol.22 No.-

이 논문은 디지털 영화시대의 심미적 기대와 심미적 체험 변화를 벤야민의 ‘충격효과’ 관점을 취한다. 비록 벤야민의 예술에 대한 관심과 사고가 20세기 전반기에 집중된 예술현상에 불과하지만, 현대예술에 대한 그의 ‘충격효과’라는 예술 이론은 전망성과 예언적 가치를 지닌 것으로, 예술에 대한 첫 번째 관심사인 ‘충격효과’의 사상가로서 디지털 영화시대의 예술작품이 가져오는 새로운 심미적 기대와 심미적 체험은 사실 벤야민의 ‘충격효과’ 이론에 대한 하나의 인증이고 설명이다. 우선 현대예술과 관련하여 벤야민이 제시한 ‘충격효과’ 이론에 대해 ‘경험’과 ‘체험’의 두 가지 사회적 존재 패턴을 비교하고, ‘제의가치’를 ‘전시가치’로 전환함으로써 ‘충격’의 개념적 의미를 살펴본다. 그 다음, ‘충격효과’ 사상의 전형적인 대표 형식인 영화의 3가지 전통적인 충격효과 효과를 분석한다. 또한 3가지 시각적 패러다임의 변화의 역사를 통해서 사람들의 심미체험과 기술적 요소가 서로 얽혀 있고 타협하여 마지막으로 형성된 사회에 적응하는 심미적 새로운 방식과 ‘심미체험’의 확장을 가져왔다. 디지털 영화시대의 대표적인 영화 디지털 기술(디지털 영상 CG 기술, 3D 입체 기술, VR 기술) 응용의 분석에 따라서 디지털 영화시대의 ‘충격효과’가 가져온 ‘심미기대’가 전통적인 ‘진실 기대’에서 ‘충격 기대’로 바뀌고 ‘충격’에 대한 ‘심미체험’을 느끼는 방식도 바꾸는 것을 논의하였다. This study adopts Walter Benjamin’s ‘Schockwirkung’ view of Changes of aesthetic expectations and aesthetic experiences in the Digital imaging era. The aesthetic expectation and aesthetic experience brought by the artistic works of the Digital imaging era are actually a confirmation and interpretation of ‘Schockwirkung’ theory. The first focus is on examines the transition from ‘worship value’ to ‘display value’ by comparing two modes of social existence: ‘experience’ and ‘experience’ the concept of ‘Schockwirkung’. Secondly, it analyzes the the three traditional impact ‘Schockwirkung’ of movies. In addition, according to the history of visual paradigm changes and the analysis of the application of representative film technology in the Digital imaging era, the aesthetic expectation brought by the of the ‘Schockwirkung’ digital film age has changed from the traditional ‘real expectation’ to ‘Schockwirkung expectation’, and the experience of ‘Schockwirkung’ the method changes and the conclusion of the thesis is reached.

Experimental and theoretical research on the compression performance of CFRP sheet confined GFRP short pole

Chen, Li,Zhao, Qilin,Jiang, Kebin Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.2

The axial compressive strength of unidirectional FRP is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. In order to restrain the lateral expansion and splitting of GFRP, and accordingly heighten its axial compressive bearing capacity, a project that to confine GFRP pole with surrounding CFRP sheet is suggested in the present study. The Experiment on the CFRP sheet confined GFRP poles showed that a combined structure of high bearing capacity was attained. Basing on the experiment research a theoretical iterative calculation approach is suggested to predict the ultimate axial compressive stress of the combined structure, and the predicted results agree well with the experimental results. Then the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure are also analyzed basing on this approach.

Strength Prediction of a Single Tooth Bound to Composite Pre-tightened Tooth Connection (PTTC) Joints based on Different Failure Criteria

Yifeng Gao,Fei Li,Qilin Zhao,Jiangang Gao,Yubo Hu 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.8

A method capable to predict the strength of single tooth bound to composite pre-tightened tooth connection (PTTC) joints is presented. The proposed method uses four representative failure criteria: max-stress, Tsai-Hill, Tsai-Wu and Hashin. The characteristic length method is also used to obtain prediction strengths. Three types of experiments of single PTTC joints were conducted using the following variations: 1) tooth depth, 2) tooth length, and 3) pre-tightened force. The experimental results were compared with the two-dimensional failure envelope diagram calculated using the four representative failure criteria. The physical nature and the strength predictive ability of each criterion were investigated. The obtained results show that the shear failure mode of single PTTC joint was accurately predicted by all four failure criteria. However, the Tsai-Wu criterion when compared to Maximum Stress, Tsai-Hill and Hashin criteria, exhibits better accuracy regarding the prediction strength of single PTTC joints, this is due to the fact that the Tsai-Wu criterion reflects more accurately the increase in the interlaminar shear strength caused by the transverse compressive stress.

Static performance of a new GFRP–metal string truss bridge subjected to unsymmetrical loads

Dongdong Zhang,Jiaxin Yuan,Qilin Zhao,Feng Li,Yifeng Gao,Ruijie Zhu,Zhiqin Zhao 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.5

A unique lightweight string truss deployable bridge assembled by thin-walled fiber reinforced polymer (FRP) and metal profiles was designed for emergency applications. As a new structure, investigations into the static structural performance under the serviceability limit state are desired for examining the structural integrity of the developed bridge when subjected to unsymmetrical loadings characterized by combined torsion and bending. In this study, a full-scale experimental inspection was conducted on a fabricated bridge, and the combined flexural–torsional behavior was examined in terms of displacement and strains. The experimental structure showed favorable strength and rigidity performances to function as deployable bridge under unsymmetrical loading conditions and should be designed in accordance with the stiffness criterion, the same as that under symmetrical loads. In addition, a finite element model (FEM) with a simple modeling process, which considered the multi segments of the FRP members and realistic nodal stiffness of the complex unique hybrid nodal joints, was constructed and compared against experiments, demonstrating good agreement. A FEM-based numerical analysis was thereafter performed to explore the effect of the change in elastic modulus of different FRP elements on the static deformation of the bridge. The results confirmed that the change in elastic modulus of different types of FRP element members caused remarkable differences on the bending and torsional stiffness of the hybrid bridge. The global stiffness of such a unique bridge can be significantly enhanced by redesigning the critical lower string pull bars using designable FRP profiles with high elastic modulus.

Numerical study on tensioned membrane structures under impact load

Yingying Zhang,Yushuai Zhao,Mingyue Zhang,Yi Zhou,Qilin Zhang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.2

This paper presents the numerical simulation of membrane structure under impact load. Firstly, the numericalsimulation model is validated by comparing with the test in Hao’s research. Then, the effects of the shape of the projectile, themembrane prestress and the initial impact speed, are investigated for studying the dynamic response and failure mechanism, basedon the membrane displacement, projectile acceleration and kinetic energy. Finally, the results show that the initial speed and thepunch shape are related with the loss of kinetic energy of projectiles. Meanwhile, the membrane prestress is an important factor thataffects the energy dissipation capacity and the impact resistance of membrane structures.

Study on load distribution ratio of composite pre-tightened tooth joint by shear nonlinearity

Yifeng Gao,Fei Li,Qilin Zhao,Jiangang Gao,Lin Shi,Zhiqin Zhao 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.5

Load distribution has a great influence on the mechanical properties of composite pre-tightened multi-tooth connection. To obtain the load distribution mechanism of composite pre-tightened multi-tooth joints, the multi-tooth joints were studied by experimental and theoretical methods. First, an experimental study was conducted on three-tooth specimens with different tooth depths and tooth lengths, and the failure mode, bearing capacity and load distribution mechanism of the specimens were obtained. Then, based on the nonlinear constitutive of interlaminar shear, an analytical model for load distribution of composite pre-tightened multi-tooth joint was proposed to research the multi-tooth load distribution mechanism. Finally, the theoretical and experimental results were compared. The research showed: (1) The theoretical results of the multi-tooth load distribution ratio were in good agreement with that of the experimental results, the maximum error between the theoretical value and the experimental value of the three-tooth joint was 17.44%, and the minimum error was only 2.35%; (2) The load distribution ratio of composite pre-tightened multi-tooth was uneven, for three-tooth joints, the values of load distribution ratio from large to small were: the first tooth, the third tooth and the second tooth.; (3) Multi-tooth load distribution ratio changed with the change of external load. The change of load distribution ratio was obvious in the early stage of loading, and tended to be gentle in the later stage of loading.