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Analysis of Penetration Depth of Pipeline on Cohesive Soil Seabed

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China Ocean Engineering 2019年第6期33卷 739-745页

作者： zhang qi-yi zhang Yuan YAN Yun-qiang WU Shao-xuan College of Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Marine Engineering in Shandong Province Qingdao 266100China

This paper conducts laboratory tests to investigate detailedly the soil deformation law around the pipeline and its penetration depth under self-gravity. The seabed model is prepared by consolidating saturated soil using vacuum pressure technology, and the pipeline models are specifically designed to possess different radii. Based on the experimental results and digital images, the soil deformation process is analyzed and summarized, a kinematic admissible velocity field is given and an upper bound solution of pipeline penetration depth and soil reaction force is derived and proposed in this paper. In order to verify the accuracy of the upper bound solution deduced in this paper,a comparison is made among some published results and the solution suggested in this paper, the comparison results confirm that the upper bound solution and the soil failure mode are reasonable. Finally two empirical formulas are given in this paper to estimate the soil reaction force of seabed and the penetration depth of pipeline. The empirical formulas are in agreement with the upper bound solution derived in this paper, and the conclusion of this paper could provide some theoretical reference for the further study of the interaction between the pipeline and the soil.

关键词： upper bound solution kinematic admissible velocity field soil reaction force penetration depth

Influence factors on activity of Ru–Zn catalysts in selective hydrogenation of benzene

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Chinese Journal of Chemical Engineering 2017年第3期25卷 294-300页

作者： qi zhang Xuhua Yan Peng Zheng Zhengbao Wang College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310027China

Selective hydrogenation of benzene is an atom economic green route to produce cyclohexene. The control of Zn species is the key to the catalytic performance of Ru–Zn catalysts. The influences of ZnO crystals on selective hydrogenation of benzene were explored. A series of Ru–Zn catalysts with different Zn contents and ZnO morphologies were prepared by changing the amount of NaOH in the co-precipitation process. The catalysts were characterized by N_2 physisorption, X-ray powder diffraction(XRD), inductively coupled plasma optical emission spectrometer(ICP-OES), scanning electron microscope(SEM), temperature-programmed reduction(H_2-TPR)and Malvern laser particle size analyzer. It is found that with increasing the amount of NaOH, the Zn content first increased then decreased, and the ZnO crystals changed from relatively thicker pyramidal-shaped crystals to slimmer needle-shaped crystals. The catalyst had the highest Zn content(22.1%) and strongest interaction between ZnO crystals and Ru particles at pH 10.6 of the solution after reduction. As a result, it had the lowest activity. The activity of Ru–Zn catalysts is affected by both the Zn content and the interaction between ZnO crystals and Ru particles. The effect of reduction time was also investigated. Prolonging the reduction time caused no significant growth of ZnO crystals but the aggregation of catalyst particles and growth of Ru nanocrystals, thus resulting in the decrease of catalytic activity.

关键词： ZnO morphology Benzene Selective hydrogenation Co-precipitation Cyclohexene

Phrase-based hashtag recommendation for microblog posts

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Science China(Information Sciences) 2017年第1期60卷 132-144页

作者： Yeyun GONG qi zhang Xiaoying HAN Xuanjing HUANG Shanghai Key Laboratory of Intelligent Information Processing School of Computer Science Fudan University

In microblogs, authors use hashtags to mark keywords or topics. These manually labeled tags can be used to benefit various live social media applications(e.g., microblog retrieval, classification). However,because only a small portion of microblogs contain hashtags, recommending hashtags for use in microblogs are a worthwhile exercise. In addition, human inference often relies on the intrinsic grouping of words into ***, existing work uses only unigrams to model corpora. In this work, we propose a novel phrase-based topical translation model to address this problem. We use the bag-of-phrases model to better capture the underlying topics of posted microblogs. We regard the phrases and hashtags in a microblog as two different languages that are talking about the same thing. Thus, the hashtag recommendation task can be viewed as a translation process from phrases to hashtags. To handle the topical information of microblogs, the proposed model regards translation probability as being topic specific. We test the methods on data collected from realworld microblogging services. The results demonstrate that the proposed method outperforms state-of-the-art methods that use the unigram model.

关键词： recommendation topic model translation phrase extraction hashtag

Structure design for high performance n-type polymer thermoelectric materials

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Chinese Physics B 2022年第2期31卷 33-43页

作者： qi zhang Hengda Sun Meifang Zhu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China

Organic thermoelectric(OTE)materials have been regarded as a potential candidate to harvest waste heat from complex,low temperature surfaces of objects and convert it into ***,n-type conjugated polymers as organic thermoelectric materials have aroused intensive research in order to improve their performance to match up with their ptype *** this review,we discuss aspects that affect the performance of n-type OTEs,and further focus on the effect of planarity of backbone on the doping efficiency and eventually the TE *** then summarize strategies such as implementing rigid n-type polymer backbone or modifying conventional polymer building blocks for more planar *** the outlook part,we conclude forementioned devotions and point out new possibility that may promote the future development of this field.

关键词： organic thermoelectrics conducting polymers organic semiconductor doping

Suggestion for aircraft flying qualities requirements of a short-range air combat mission

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Chinese Journal of Aeronautics 2017年第3期30卷 881-897页

作者： Lixin WANG Youguang GUO qi zhang Ting YUE School of Aeronautic Science and Engineering Beihang University Beijing 100191 China

Owing to the lack of a direct link with the operations in short-range air combat,conventional aircraft flying qualities criteria are inappropriate to guide the design of a task-tailored flight control *** applying the mission-oriented flying qualities evaluation approach,various aircraft with different control law parameters are evaluated on a ground-based *** paper compares the evaluation results with several conventional flying qualities criteria,and discusses the appropriate parameter combination to reflect the flying qualities requirements of short-range air *** comparison and analysis show that a short-range air combat mission requires a higher minimum short period mode natural frequency and a smaller maximum roll mode time constant,and allows a lower minimum pitch attitude bandwidth and a higher maximum short period mode damp ratio than those of conventional flying qualities ***,a combination of the pitch attitude bandwidth,the pitch attitude magnitude at the bandwidth frequency,and the pitch attitude transfer function gain can define the flying qualities requirements of short-range air *** new metric can successfully predict the flying quality levels of aircraft in a short-range air combat mission.

关键词： Acquisition Flying qualities of fighter aircraft Mission requirements Multi-axis task Short-range air combat Tracking

Credit Determination of Fibre Channel in Avionics Environment

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Chinese Journal of Aeronautics 2007年第3期20卷 247-252页

作者： LIN qiang XIONG Hua-gang zhang qi-shan School of Electronic and Information Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

Fibre channel （FC） is the main candidate architecture for ＂unified network＂. Flow control deals with the problem in which a device receives frames faster than it can process them. Credit is an important service parameter for fibre channel flow control. Configuring the credit reasonably can avoid buffer overflow in nodes. This paper derives the mathematic relationships among credit, bandwidth and message sets under real-time condition according as three main topologies of fibre channel, and proposes the credit determination and the optimal credit for typical message sets. This study is based on the features of hard real-time communications in avionics environment.

关键词： fibre channel topology login credit hard real-time condition

Relevance between fractional-order hybrid model and unified equivalent circuit model of electric vehicle power battery

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Science China(Information Sciences) 2018年第7期61卷 98-100页

作者： qi zhang Naxin CUI Yunlong SHANG Guojing XING Chenghui zhang School of Control Science and Engineering Shandong University

Lithium-ion battery has gradually become the main power battery for electric *** models play an important role in battery design and safe ***,an accurate,intuitive,and efficient model is not available easily,because it is highly complex,nonlinear and *** models are divided into electrochemical model,thermal model,stochastic model,neural network model,and equivalent circuit model

关键词： CF Ba Relevance between fractional-order hybrid model and unified equivalent circuit model of electric vehicle power battery OCV Figure

Plastic Mechanism of Multi-pass Double-roller Clamping Spinning for Arc-shaped Surface Flange

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1127-1137页

作者： FAN Shuqin ZHAO Shengdun zhang qi LI Yongyi School of Mechanical Engineering Xi’an Jiaotong University

Compared with the conventional single-roller spinning process, the double-roller clamping spinning（DRCS） process can effectively prevent the sheet metal surface wrinkling and improve the the production efficiency and the shape precision of final spun part. Based on ABAQUS/Explicit nonlinear finite element software, the finite element model of the multi-pass DRCS for the sheet metal is established, and the material model, the contact definition, the mesh generation, the loading trajectory and other key technical problems are solved. The simulations on the multi-pass DRCS of the ordinary Q235A steel cylindrical part with the arc-shaped surface flange are carried out. The effects of number of spinning passes on the production efficiency, the spinning moment, the shape error of the workpiece, and the wall thickness distribution of the final part are obtained. It is indicated definitely that with the increase of the number of spinning passes the geometrical precision of the spun part increases while the production efficiency reduces. Moreover, the variations of the spinning forces and the distributions of the stresses, strains, wall thickness during the multi-pass DRCS process are revealed. It is indicated that during the DRCS process the radical force is the largest, and the whole deformation area shows the tangential tensile strain and the radial compressive strain, while the thickness strain changes along the generatrix directions from the compressive strain on the outer edge of the flange to the tensile strain on the inner edge of the flange. Based on the G-CNC6135 NC lathe, the three-axis linkage computer-controlled experimental device for DRCS which is driven by the AC servo motor is developed. And then using the experimental device, the Q235A cylindrical parts with the arc-shape surface flange are formed by the DRCS. The simulation results of spun parts have good consistency with the experimental results, which verifies the feasibility of DRCS process and the reli

关键词： spinning double-roller clamping multi-pass arc-shaped surface

Structured trajectory planning of collision-free lane change using the vehicle-driver integration data

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Science China(Technological Sciences) 2016年第5期59卷 825-831页

作者： WANG Jiang Feng zhang qian zhang Zhi qi YAN Xue Dong MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology Beijing Jiaotong University

In this paper, the structured trajectory planning of lane change in collision-free road environment is studied and validated using the vehicle-driver integration data, and a new trajectory planning model for lane change is proposed based on linear offset and sine function to balance driver comfort and vehicle dynamics. The trajectory curvature of the proposed model is continuous without mutation, and the zero-based curvature at the starting and end points during lane change assures the motion direction of end points in parallel with the lane line. The field experiment are designed to collect the vehicle-driver integration data, such as steering angle, brake pedal angel and accelerator pedal angel. The correction Correlation analysis of lane-changing maneuver and influencing variables is conducted to obtain the significant variables that can be used to calibrate and test the proposed model. The results demonstrate that vehicle velocity and Y-axis acceleration have significant effects on the lane-changing maneuver, so that the model recalibrated by the samples of different velocity ranges and Y-axis accelerations has better fitted performance compared with the model calibrated by the sample trajectory. In addition, the proposed model presents a decreasing tendency of the lane change trajectory fitted MAE with the increase of time span of calibrating samples at the starting stage.

关键词： intelligent vehicle lane change trajectory planning vehicle-driver integration