Numerical Study on Thermodynamic Performance in a Cryogenic Fuel Storage Tank Under External Sloshing Excitation

Zhan Liu,Hong Chen,Qiang Chen,Liubiao Chen 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.5

Fluid sloshing usually causes some serious safety issues during the transportation and utilization of liquid fuel in different engineering applications. In this paper, a computational fluid dynamics model is established to investigate the thermal physical process and sloshing hydrodynamics in a cryogenic fuel storage tank. Both the experimental validation and calculation grid sensitive analysis are conducted. The present numerical calculation model was turned out to be acceptable and proper for fluid sloshing prediction. Based on the proposed numerical model, the sloshing force and moment, the tank pressure variation, the fluid temperature distribution and the dynamic response of the free surface are investigated and analyzed respectively. The results show that the sinusoidal excitation has obvious influences on the thermodynamic and hydrodynamics performance in cryogenic fuel storage tanks. With some valuable conclusions obtained, this study is of significance to the depth understanding on the non-isothermal fluid sloshing, and may supply some technique supports for the safety design of cryogenic storage tanks.

Let-7c Inhibits NSCLC Cell Proliferation by Targeting HOXA1

Zhan, Min,Qu, Qiang,Wang, Guo,Liu, Ying-Zi,Tan, Sheng-Lan,Lou, Xiao-Ya,Yu, Jing,Zhou, Hong-Hao Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

Objective: The aim of the present study was to explore mechanisms by which let-7c suppresses NSCLC cell proliferation. Methods: The expression level of let-7c was quantified by qRT-PCR. A549 and H1299 cells were transfected with let-7c mimics to restore the expression of let-7c. The effects of let-7c were then assessed by cell proliferation, colony formation and cell cycle assay. Mouse experiments were used to confirm the effect of let-7c on tumorigenicity in vivo. Luciferase reporter assays and Western blotting were performed to identify target genes for let-7c. Results: HOXA1 was identified as a novel target of let-7c. MTS, colony formation and flow cytometry assays demonstrated that forced expression of let-7c inhibited NSCLC cell proliferation by inducing G1 arrest in vitro, consistent with inhibitory effects induced by knockdown of HOXA1. Mouse experiments demonstrated that let-7c expression suppressed tumorigenesis. Furthermore, we found that let-7c could regulate the expression of HOXA1 downstream effectors CCND1, CDC25A and CDK2. Conclusions: Collectively, these results demonstrate let-7c inhibits NSCLC cell proliferation and tumorigenesis by partial direct targeting of the HOXA1 pathway, which suggests that restoration of let-7c expression may thus offer a potential therapeutic intervention strategy for NSCLC.

A novel active disturbance rejection-based control strategy for a gun control system

Qiang Gao,Zhan Sun,Guolai Yang,Runmin Hou,Li Wang,Yuan-Long Hou 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.12

To compensate for the nonlinearity and to achieve finely-tuned tracking accuracy of a gun control system driven by an AC machine,an improved active disturbance rejection control (IADRC) strategy with neural network embedding (NN-IADRC) is developed in this paper. The proposed IADRC, which has amnestic memory effects, can be regarded as an extension of the conventional ADRC (CADRC),making it a special case of the IADRC. To further attenuate the dependence on system models and enhance the disturbance rejection capacities of the IADRC strategy, an on-line NN-based optimum updating approach is also developed in this paper. Finally, a series of experiments are conducted on the semi-physical simulation platform to estimate the performance of the control system and the effects of the memory factor on the system. The experimental results confirm that the proposed NN-IADRC is highly robust. The results also confirm that it performs more excellently than the CADRC and that its fine tuning has attained tracking accuracy.

The Kinematic Calibration of a Drilling Robot with Optimal Measurement Configurations Based on an Improved Multi-objective PSO Algorithm

Xiangzhen Chen,Qiang Zhan 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.9

In aircraft assembly, robot drilling system has been widely used to enhance the efficiency and quality of assembly holes’ manufacturing. However, the industrial robot used by the drilling robot has low absolute positioning accuracy, which cannot meet the hole positioning accuracy requirement of aircraft components, so the drilling robot must be calibrated. The kinematic calibration effect is sensitive to the selection of measurement configurations. Although different observability indexes have been proposed to evaluate the measurement configurations, it is difficult to obtain precise kinematic parameters and minimize the uncertainty of end-effector positions simultaneously with a single observability index. At the same time, current measurement configurations optimization algorithms are still prone to fall into local optimization trap and boundary optimization trap. In order to improve the calibration accuracy of the drilling robot, an improved multi-objective particle swarm optimization algorithm was proposed to search the measurement configurations in the limited workspace, and the “rebound” particle was proposed to avoid local convergence. The effectiveness of the proposed algorithm was verified by simulations and calibration experiments of a drilling robot with KUKA KR500L340-2. Results show that the proposed algorithm can effectively obtain the measurement configurations with the maximum comprehensive observability index, and the positions of the measurement configurations could avoid the search boundary. Meanwhile, more accurate kinematic parameters of the drilling robot can be calculated by using the optimal measurement configurations searched by the proposed algorithm, and the end-effector position accuracy is 26.94% higher than that calibrated with randomly selected measurement configurations.

The Design of Malocclusion Model Diagnosis and Treatment Planning CAD System

Hong, Zhao,qiang, Zhai Zhan,Zheng, Wang Yu,Yie, Ke,Zhu, Lin 대한전자공학회 1992 HICEC:Harbin International Conference on Electroni Vol.1 No.1

Malocclusion model diagnosis and treatment is an important branch of stomatology. It means that dental diseases is treated through diagnosis and correction of dental deformity disease. In this paper, the objective, content, and method of malocclusion model diagnosis and treatment planning CAD system are introduced. Using the system, dentists are able to capture the image of dental cast, measure three dimensional feature points, extract specialized feature data, express teeth and gum with certain data structure, then provide the basis for design of treatment scheme. According to the feature points the feature data, computer aided design and simulation can be performed. The working efficiency and treatment effectivity of dentists can be improved in consequence.

Residual Surface Topology Modeling and Simulation Analysis for Micro-Machined Nozzle

Yukui Cai,Zhan-qiang Liu,Zhen-yu Shi,Qinghua Song,Yi Wang 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

The performance of the micro nozzle is determined primarily by its machined surface topology. A circular cross-section micro-Lavalnozzle is modeled and studied by using numerical simulation in this paper. The geometry of residual height and residual area ofmachined nozzle surface with flat-end milling cutter and ball-end milling cutter are created. It is found that the ball end milling cutterwith large diameter is better than the flat one for nozzle finishing operations. The nozzle velocity performance is also revealed in thisresearch. When residual height increased from 0.6 μm to 9.6 μm for nozzle with throat diameter less than 2 mm, the maximum outletvelocity of nozzle reduced gradually. The maximum outlet velocity of nozzle remains stable for the nozzle with throat diameter greaterthan 2 mm. The results show that the maximum outlet velocity of nozzle significantly reduces with throat diameter decreasing underconstant residual height. Based on the analysis about velocity boundary layer, when residual height changing from 0.6 μm to 9.6 μm,the nozzle with throat diameter is 1 mm, has the boundary layer thickness ranging from 5% to 14% of outlet radius.

Wavelet based Macrotexture Analysis for Pavement Friction Prediction

Guangwei Yang,Qiang Joshua Li,You Jason Zhan,Kelvin C. P. Wang,Chaohui Wang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

Pavement friction and texture characteristics are important aspects of road safety. Despite extensive studies conducted in the past decades, knowledge gaps still remain in understanding the relationship between pavement macrotexture and surface skid resistance. This paper implements discrete wavelet transform to decompose pavement surface macrotexture profile data into multi-scale characteristics and investigate their suitability for pavement friction prediction. Pavement macrotexture and friction data were both collected within the wheel-path from six High Friction Surface Treatment sites in Oklahoma using a high-speed profiler and a Grip Tester. The collected macrotexture profiles are decomposed into multiple wavelengths, and the total and relative energy components are calculated as indicators to represent macrotexture characteristics at various wavelengths. Correlation analysis is performed to examine the contribution of the energy indicators on pavement friction. The macrotexture energy within wavelengths from 0.97 mm to 3.86 mm contributes positively to pavement friction while that within wavelengths from 15.44 mm to 61.77 mm shows negative impacts. Subsequently, pavement friction prediction model is developed using multivariate linear regressive analysis incorporating the macrotexture energy indicators. Comparisons between predicted and monitored friction data demonstrates the robustness of the proposed friction prediction model.

Size Effect on Surface Roughness in Micro Turning

Tao Zhang,Zhan-qiang Liu,Zhen-yu Shi,Chong-hai Xu 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

The conventional model predicts that the surface roughness decreases with feed and fits well with the measured results, even in the micro turning process. But it is observed that surface roughness increases with feed decreases when the feed is in the range of micro scale. Based on the analysis of peak-to-valley formation process, a quadratic prediction model, which divides the height of peak-tovalley into two parts: one part is piled in front of the rake face while the other is piled on the flank face and is more accurate, is established considering the effect of tool geometry, cutting parameters and pile-up of work piece. The prediction model is calibrated and verified via two groups of micro turning experiments. Results show that size effect of specific cutting energy increases the surface roughness at small feeds. The difference between the theoretical and measured results at small feeds is mainly induced by the pileup of work piece material around the rear face. The best surface roughness can be obtained when the feed per revolution equals 0.1time of the cutting edge radius.

An Approach for Reducing Cutting Energy Consumption with Ultra-High Speed Machining of Super Alloy Inconel 718

Bing Wang,Zhan-qiang Liu,Qinghua Song,Yi Wang,iaoping Ren 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.1

High energy efficient machining is beneficial for sustainable manufacture which is an important target pursued by workshops. The paper aims to prove the feasibility for reducing cutting energy consumption with ultra-high speed machining (UHSM) of super alloy Inconel 718. Firstly, orthogonal cutting experiments of Inconel 718 are performed with a wide cutting speed range. Through analyses of chip micrographs, it is found that plastic deformation accompanied with ductile fracture contributes to serrated chip formation, while fragmented chips are produced through brittle fracture. The results demonstrate that brittle regime machining can be realized for Inconel 718 with ultra-high cutting speeds. Secondly, considering varied deformation behavior for chips with different morphologies, specific cutting energy models for HSM under varied cutting parameters are developed and verified. Then the influences of cutting speed and uncut chip thickness on cutting energy consumption during HSM are revealed. The research results demonstrate the practicability for reducing cutting energy consumption with brittle regime machining of Inconel 718. At last, the relationship between AE signals and cutting energy consumption is explored, and it proves that AE signals are applicable in monitoring cutting energy consumption. The research can provide guidance for energy saving through optimizing cutting parameters.

Using the Eigenvalue Partition to Compute the Automorphism Group

HAO Jian-Qiang,GONG Yun-Zhan,LIU Hong-Zhi 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.6

To solve the automorphism group of a graph is a fundamental problem in graph theory. Moreover, it usually is an essential process for graph isomorphism testing. At present, because existing algorithms ordinarily cannot efficiently compute the automorphism group of a graph, ones cannot entirely resolve the graph isomorphism problem. To calculate the automorphism group of a weighted graph, first, briefly review the history of automorphism. Second, introduce the concept of eigenvalue partition. Third, using algebraic methods, examine not only the relationships between the diagonal form of an adjacency matrix and its eigenvalues and eigenvectors, but also the relationships between its eigenvalues and eigenvectors and the automorphism group. Furthermore, prove Theorem 2 to 8. In addition, propose Conjecture 1 and three open problems. By these theorems, present a novel method to resolve the automorphism group of a weighted graph. If a graph has no duplicate eigenvalues and Conjecture 1 is true, it can determine the automorphism group of a weighted graph in polynomial time by the method. Although this method has certain limitations and needs improvements, it is theoretically a necessary complement to solve the automorphism group. Finally, it shows the close relationships that exist between an orthogonal matrix and a permutation matrix, also an orthogonal matrix and an automorphism.