Evaluation of Solar Temperature Field under Different Wind Speeds for Shanghai 65 m Radio Telescope

Hongliang Qian,Deshen Chen,Feng Fan,Ye Liu,Shi-zhao Shen 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.2

The Shanghai 65 m radio telescope is currently the largest full range rotatable radio telescope in Asia. Gravity, wind and temperature are the three main factors which may have a bad effect on the reflector’s surface precision. To study the effect of the thermal deformation caused by daily non-uniform temperature fields on the surface precision of the main reflector, both the temperature field and its effect were studied in detail for two typical days (January 15th and July 15th). The method to simulate temperature fields was studied initially, considering heat conduction, solar radiation, shadowing, air convection, sky radiation and ground radiation. Then, an integral parametric thermal finite element model (FEM) of the telescope was established using the ANSYS thermal analysis module. Finally, the effect of non-uniform temperature fields on the surface precision of the main reflector was estimated in terms of the Root Mean Square (RMS) deformation based on temperature transient analysis. The proposed methods and conclusions drawn can provide valuable information for thermal design, thermal monitoring and thermal control of the Shanghai 65 m radio telescope and other similar giant antenna structures.

Stress-Release Law and Deformation Characteristics of Large-Span Tunnel Excavated with Semi Central Diaphragm Method

Shen Zhou,Liping Li,Zhimin An,Hongliang Liu,Guangyu Yang,Pengfei Zhou 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.6

The proportion of large-span tunnels in newly-built highway tunnels is getting higher and higher, revealing the stress release law and deformation characteristics of the tunnel at different excavation steps has important guiding significance for the rational design of the supporting structure parameters. In this paper, a typical section of the Laohushan Tunnel was selected to analyze the stress and deformation response of the large-span tunnel excavated with the semi central diaphragm method (SCDM), with the numerical simulation and field monitoring method. The study found that during the excavation of the large-span tunnel with the SCDM, the stress and deformation response characteristics are different from those ordinary tunnels. Influenced by the settlement of the vault, there was a significant outward expansion tendency, and a high degree of stress concentration in the sidewall. In particular, the supporting structure at the sidewall has a deformation characteristic of expanding outward and then converging inward. In this paper, the in-depth analysis of the stress release law and deformation characteristics of the excavation process of large-span tunnels can provide reference for the excavation and support parameter design of similar projects.

Advanced Stability Analysis of the Tunnels in Jointed Rock Mass Based on TSP and DEM

Hongyun Fan,Liping Li,Hongliang Liu,Shaoshuai Shi,Jie Hu,Shen Zhou 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.4

The discrete element method (DEM) can analyze the large deformation and large displacement of rock mass effectively, and it is widely used in underground engineering, slope engineering and other fields. However, due to the low accuracy of rock mass structural surface information acquisition, the application of discrete element method in the analysis of jointed rock mass stability is still deviated. In this paper, combined with the advantages of the tunnel seismic prediction (TSP) in obtaining discontinuous geological interface information and the discrete element method in the calculation and analysis of jointed rock mass stability, this paper proposes an advanced analysis method for jointed rock mass stability based on TSP and DEM. Compared to the traditional methods, the analysis results of the jointed rock mass stability are more reliable. Firstly, relying on the advanced detection system – Tunnel Seismic Prediction 203Plus, the unstructured rock mass structure information of the tunnel is obtained, and the spatial attitude of the discontinuous geological interface is further determined. Secondly, based on the Fish programming language, the non-continuous geological interface information can be expressed in the discrete unit software – 3D Distinct Element Code (3DEC). In this way, the excavation calculation model of the tunnels in jointed rock mass can be constructed. Finally, based on the DEM, the excavation of the tunnels in jointed rock mass can be simulated, analyze the stability of surrounding rock during the tunnel excavation process, and realize the stability analysis of surrounding rock stability of jointed rock mass. Based on the Huangjiazhuang Tunnel Project, this paper uses the above method to carry out on-site application. The results show that the location of the dangerous block is predicted to be consistent with the actual exposure of the tunnel surrounding rock based on TSP and DEM, which verify the accuracy and feasibility of this method, and the research results have practical guiding significance for the safe construction of the tunnels in jointed rock mass.

An Estimate of the Time-varying Temperature Field of the Main Reflector and Subreflector of the Shanghai 65 m Radio Telescope under Solar Illumination

Zhong Jie,Qian Hongliang,Fan Feng,Shen Shizhao 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.1

The time-dependent temperature fields of the reflectors of the Shanghai 65 m radio telescope are investigated numerically, taking account of the non-uniform heating of the reflector surfaces due to solar illumination and the constantly changing ambient air temperature. This paper utilizes a ray casting algorithm to calculate the borderline separating the reflector areas in shadow and in sunshine, aiming to provide an accurate calculation of the solar energy absorbed. Then a ray tracing algorithm is utilized to calculate the total solar energy that is reflected by the main reflector area and received by the subreflector surface area. Finally, the solar energy is used as the main thermal load on the reflector surface to numerically examine the temperature distribution on both the main reflector and the subreflector. The results illustrate that the time-varying temperature fields of the reflectors of a radio telescope due to asymmetric solar illumination can be accurately simulated utilizing the ray casting algorithm and the ray tracing algorithm. The occurring periods and avoidance zones of the overheating of the subreflector are identified, among which the maximum temperature of the subreflector reaches 144.9oC. These dangerous observation zones should be avoided during the operation of the radio telescope.

Simultaneous Impact of Multiple Droplets on Liquid Film

Gangtao Liang,Tianyu Zhang,Haibing Yu,Hongliang Chen,Shengqiang Shen 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.65 No.-

Multiple droplets impinging on a thin liquid film simultaneously is numerically studied using a three-dimensional model with an implement of a random disturbance subjected to Gaussian distribution. This model is very effective to predict droplet splashing under relatively high impingement momentum. Interface evolutions and field distributions are addressed after droplets impact. Besides, a geometric model is built up to demarcate the impact region into two semicircular regions and a series of rectangular regions during simultaneous impact, further to discuss the variations of area and residual film thickness in each region as well as the total area and average film thickness.

Analysis of longissimus muscle quality characteristics and associations with DNA methylation status in cattle

Zhi Chen,Shuangfeng Chu,Xin Xu,Jingyi Jiang,Wenqiang Wang,Hongliang Shen,Mingxun Li,Huimin Zhang,Yongjiang Mao,Zhangping Yang 한국유전학회 2019 Genes & Genomics Vol.41 No.10

Background As cattle represent one of the most important livestock species for meat production, control of muscle development in regards to quality is an important research focus. Objectives In this study, the phenotypic quality traits and its associations with DNA methylation levels of the longissimus muscle in two cattle breeds were studied. Methods The pH value, water loss rate, fat and protein and fatty acid content were measured in three beef cattle breeds of longissimus mucle; The longissimus mucle was analyzed by MethylRAD-seq and RNA-seq. The differentially methylated and differentially expressed related genes were subjected to BSP. Results Methylation status of longissimus mucle was analyzed by MethylRAD-seq. Compared with Simmental, there were 39 differentially methylated and expressed genes in muscle of Yunling cattle, and 123 differentially methylated and expressed genes in Wenshan muscle. A combined analysis of MethylRAD-seq and RNA-seq results revealed differential methylation and expression level of 18 genes between Simmental and Wenshan cattle, and 14 genes between Simmental and Yunling cattle. In addition, 28 genes were differentially methylated between Wenshan and Yunling cattle. Results of promoter methylation analysis of ACAD11, FADS6 and FASN showed that the overall degree of DNA methylation of FADS6 and FASN was negatively correlated with their expression levels. Methylation level of FASN in Simmental was greater than Yunling and Wenshan. The degree of methylation at the FADS6 CpG4 site was significantly higher in Simmental than that in Yunling. The levels of methylation at the CpG7 locus of the Simmental and Yunling breeds were greater than Wenshan cattle. A negative correlation was detected between the methylation levels and the expression of FASN CpG1, CpG2, CpG3, CpG5, CpG7, and CpG10. Conclusion The functional and molecular regulatory mechanism of the genes related to meat quality can be revealed systematically from aspects of the genetic and epigenetic regulation. These studies will help to further explore the molecular mechanisms and phenotypic differences that regulate growth and quality of different breeds of cattle.