A comparative study of hydraulic fracturing with various boreholes in coal seam

Honglei Liu,Tianhong Yang,Tao Xu,Qinglei Yu 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.3

Comparative numerical study on hydraulic fracturing with various boreholes in coal seam combined with in situ experiments was carried out to investigate the fracturing mechanism and loosening effect of hydraulic fracturing in coal seam. Hydraulic fracturing models with single-borehole, three-borehole and fiveborehole were built based on in situ tests in Chengshan coalmine, Jixi city, Heilongjiang province, China and the changes of water pressure and shear stress around boreholes during hydraulic fracturing were analyzed. The influence of hydraulic fracturing with controlling borehole on crack initiation and propagation was discussed. According to the in situ testing results, it is found that controlling boreholes in hydraulic fracturing not only can control the direction of crack propagation, but also can judge the effect of crack initiation and breakdown. The work in this paper is of great importance for the design of hydraulic fracturing technology and the alternative of the parameters in theory and practice.

Simulation and Design Considerations on Transverse Connection of Prestressed Concrete T-girder Bridge

Chen Chen,Caiqian Yang,Yong Pan,Honglei Zhang,Hans De Backer 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4

In this paper, the structural performance of the prestressed concrete T-girder bridge with a newly proposed diaphragm transverse connections (DTCs) have been investigated. The DTCs are composed of diagonal braces and horizontal brace, and the braces are structural steel with square cross section. A series of simulations have been carried out to study the eff ectiveness of the proposed DTCs on enhancing the transverse connection of the prestressed concrete T-girder bridge. Load Model 1 in accordance with Eurocode 1 is considered in the simulations, which consists of tandem system and uniformly distributed loads (UDL system). The Von Mises stress of the DTCs has been checked and corresponding steel grade has been given. The force on the surface between the T-girder bridge and the proposed DTCs has been studied and detailed connection design has been given for both new bridge construction and existing bridge retrofi tting. The simulation results show that the maximum defl ection arises when the deck is fully loaded with the UDL system and with lane 1 centrally located on exterior girder, and the tandem systems are applied at midspan simultaneously. It is revealed that with the proposed DTCs installed at midspan, the maximum defl ection of the prestressed concrete T-girder bridge reduces 12.8% in the most unfavorable load case. In all the discussed load cases, the Von Mises stress of the proposed DTCs is within the reasonable range and can be borne by normal steel material. Additionally, connection methods have been given for the DTCs’ application to new bridge and existing bridge. For the use of chemical anchor in existing bridge, the concrete and prestress tendons should be checked in case of any additional damage during the installing of the DTCs.

A Fiber Spool’s Vibration Sensitivity Optimization Based on Orthogonal Experimental Design

Jing Gao,Linbo Zhang,Dongdong Jiao,Guanjun Xu,Xue Deng,Qi Zang,Honglei Yang,Ruifang Dong,Tao Liu,Shougang Zhang 한국광학회 2024 Current Optics and Photonics Vol.8 No.1

A fiber spool with ultra-low vibration sensitivity has been demonstrated for the ultra-narrowlinewidth fiber-stabilized laser by the multi-object orthogonal experimental design method, which can achieve the optimization object and analysis of influence levels without extensive computation. According to a test of 4 levels and 4 factors, an L 16 (4 4 ) orthogonal table is established to design orthogonal experiments. The vibration sensitivities along the axial and radial directions and the normalized sums of the vibration sensitivities are determined as single objects and comprehensive objects, respectively. We adopt the range analysis of object values to obtain the influence levels of the four design parameters on the single objects and the comprehensive object. The optimal parameter combinations are determined by both methods of comprehensive balance and evaluation. Based on the corresponding fractional frequency stability of ultra-narrow-linewidth fiber-stabilized lasers, we obtain the final optimal parameter combination A3B1C2D1, which can achieve the fiber spool with vibration sensitivities of 10 −12 /g magnitude. This work is the first time to use an orthogonal experimental design method to optimize the vibration sensitivities of fiber spools, providing an approach to design the fiber spool with ultra-low vibration sensitivity.

Comparative transcriptome analysis of salt-sensitive and salt-tolerant maize reveals potential mechanisms to enhance salt resistance

Mingquan Wang,Yufeng Wang,Yifei Zhang,Chunxia Li,Shichen Gong,Shuqin Yan,Guoliang Li,Guanghui Hu,Honglei Ren,Jianfei Yang,Tao Yu,Kejun Yang 한국유전학회 2019 Genes & Genomics Vol.41 No.7

Background Salt stress is a devastating environmental stress that causes plant growth inhibition and yield reduction. Objective The identification of salt-tolerant genes brings hope for the generation of salinity-tolerant crop plants through molecular breeding. Methods In this study, one salt-sensitive and one salt-tolerant maize inbred line were screened from 242 maize inbred lines. Reactive oxygen species (ROS)-related enzyme activities were detected and salt-responsive comparative transcriptome analysis was performed for control and 220 mM NaCl treated maize leaves. Results Salt-tolerant maize inbred line (L87) showed higher ROS-related enzyme (SOD, POD, APX and CAT) activities and accumulated relatively lower levels of ROS under salt stress. Of the total DEGs, 1856 upregulated DEGs were specific to L87, including stress tolerance-related members of the 70kDa family of heat shock proteins (Hsp70s) and aquaporins. The DEGs involved in the abscisic acid (ABA), ethylene, jasmonic acid (JA) and salicylic acid (SA) signal transduction pathways may determine the difference in salt tolerance between the two varieties, especially one central component SnRK2, that positively regulates ABA signaling and was only upregulated in L87. Analysis of DEGs related to ROS scavenging showed that some peroxidase (POD), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) genes specific to L87 probably enhanced its salt tolerance. The analysis of differentially expressed transcription factors (TFs) suggested that WRKY TFs could contribute to the difference in salt tolerance between the two maize lines. Conclusion Compared with Salt-sensitive maize inbred line (L29), L87 exhibits specific regulatory mechanisms related to salt tolerance, including plant hormone interactions, ROS scavenging and the regulation of TFs. Our study identifies new candidate genes that may regulate maize tolerance to salt stress and provides useful information for breeding maize with high salt resistance.

Imaging Assessment of Visceral Pleural Surface Invasion by Lung Cancer: Comparison of CT and Contrast-Enhanced Radial T1-Weighted Gradient Echo 3-Tesla MRI

Zhang Yu,Kwon Woocheol,Lee Ho Yun,Ko Sung Min,Kim Sang-Ha,Lee Won-Yeon,Yong Suk Joong,Jung Soon-Hee,Byun Chun Sung,Lee JunHyeok,Yang Honglei,Han Junhee,Ackman Jeanne B. 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.5

Objective: To compare the diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3-tesla (3T) magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of visceral pleural surface invasion (VPSI). Visceral pleural invasion by non-small-cell lung cancer (NSCLC) can be classified into two types: PL1 (without VPSI), invasion of the elastic layer of the visceral pleura without reaching the visceral pleural surface, and PL2 (with VPSI), full invasion of the visceral pleura. Materials and Methods: Thirty-three patients with pathologically confirmed VPSI by NSCLC were retrospectively reviewed. Multidetector CT and contrast-enhanced 3T MRI with a free-breathing radial three-dimensional fat-suppressed volumetric interpolated breath-hold examination (VIBE) pulse sequence were compared in terms of the length of contact, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. Supplemental evaluation of the tumor-pleura interface (smooth versus irregular) could only be performed with MRI (not discernible on CT). Results: At the tumor-pleura interface, radial VIBE MRI revealed a smooth margin in 20 of 21 patients without VPSI and an irregular margin in 10 of 12 patients with VPSI, yielding an accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F-score for VPSI detection of 91%, 83%, 95%, 91%, 91%, and 87%, respectively. The McNemar test and receiver operating characteristics curve analysis revealed no significant differences between the diagnostic accuracies of CT and MRI for evaluating the contact length, angle of mass margin, or arch distance-to-maximum tumor diameter ratio as predictors of VPSI. Conclusion: The diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3T MRI and CT were equal in terms of the contact length, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. The advantage of MRI is its clear depiction of the tumor-pleura interface margin, facilitating VPSI detection.