Rapid Treatment Using Vacuum-surcharge Preloading with Dynamic Consolidation Method: Laboratory Model Test

Xiaobing Li,Jun Li,You Zhou,Tian Jin,Mingfeng Li 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

This study presents an experimental investigation of reinforcement effect of dredged fill obtained from the Oufei project of Wenzhou, China using improved method of vacuum-surcharge preloading with dynamic consolidation by five parallel laboratory model tests: four model tests with different tamping energy combinations and a control group of vacuum-surcharge preloading method. The water content after treatment of the vacuum-surcharge preloading method was close to the optimal water content obtained from standard compactiontest. The treatment of improved method of vacuum-surcharge preloading with dynamic consolidation can improve reinforcement effect and shorten consolidation time. The tests with higher tamping energy have a higher range of improvement. Under the condition of the identical level of tamping energy, compared with the drop height, the weight of hammer plays a greater role in foundation reinforcement, embodying concretely in water discharge, crater depth, and dissipation of pore water pressure, water content, vane shear strength, and porosity.The findings from this study may benefit the engineering application and further research of the combined method.

Gene Expression Analysis of Phanerochaete chrysosporium During the Transition Time from Primary Growth to Secondary Metabolism

Mingfeng Jiang,Xiao Li,Liang Zhang,Hong Feng,Yizheng Zhang 한국미생물학회 2009 The journal of microbiology Vol.47 No.3

In order to identify the secondary metabolism-related genes of Phanerochaete chrysosporium growing under pure O2 and nitrogen-limited conditions, 2322 ESTs fragments originated from two suppression-subtractive libraries were analyzed using the cDNA microarray technique. Ten significantly upregulated and 22 significantly downregulated genes were identified in the 72 h cultured mycelia RNA samples (secondary metabolism). According to qPCR, 16 out of the 32 genes were expressed differently in secondary metabolism. Transcripts of secondary metabolism up-regulation genes exhibited homologies to aryl-alcohol dehydrogenase (SSh1554), ABC transporter gene (SSH624), chitinase (SSH963), heat shock protein (SSH1193), catalase (SSH317), cytochrome P450 (SSH331), glucosamine-6-phosphate isomerase (SSH611), and alkyl hydroperoxide reductase (SSH362) genes. Ninety-three genes could be classified by Eukaryotic Orthologous Groups (KOG). Among the genes assigned a function, gene expression patterns were different in both secondary metabolism and primary metabolism. In the group of “Cellular Processes and Signaling,” most of the genes were from the primary metabolism library. On the other hand, genes from the secondary metabolism library were found mainly in the “Information Storage” and “Processing and Poorly Characterized” groups. Based on the KOG functional assignments, six genes belong to the ubiquitin system, and all of them were from primary metabolism phase. The presence of the H2O2-relevant genes suggested that parts of the genes expressed in 72 h might be involved in the ligninolytic process during secondary metabolism of P. chrysosporium.

Non-stationary statistical modeling of extreme wind speed series with exposure correction

Mingfeng Huang,Qiang Li,Haiwei Xu,Wenjuan Lou,Ning Lin 한국풍공학회 2018 Wind and Structures, An International Journal (WAS Vol.26 No.3

Extreme wind speed analysis has been carried out conventionally by assuming the extreme series data is stationary. However, time-varying trends of the extreme wind speed series could be detected at many surface meteorological stations in China. Two main reasons, exposure change and climate change, were provided to explain the temporal trends of daily maximum wind speed and annual maximum wind speed series data, recorded at Hangzhou (China) meteorological station. After making a correction on wind speed series for time varying exposure, it is necessary to perform non-stationary statistical modeling on the corrected extreme wind speed data series in addition to the classical extreme value analysis. The generalized extreme value (GEV) distribution with time-dependent location and scale parameters was selected as a non-stationary model to describe the corrected extreme wind speed series. The obtained non-stationary extreme value models were then used to estimate the non-stationary extreme wind speed quantiles with various mean recurrence intervals (MRIs) considering changing climate, and compared to the corresponding stationary ones with various MRIs for the Hangzhou area in China. The results indicate that the non-stationary property or dependence of extreme wind speed data should be carefully evaluated and reflected in the determination of design wind speeds.

Expression, Purification, and Characteristic of Tibetan Sheep Breast Lysozyme Using Pichia pastoris Expression System

Li, Jianbo,Jiang, Mingfeng,Wang, Yong Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.4

A lysozyme gene from breast of Tibetan sheep was successfully expressed by secretion using a-factor signal sequence in the methylotrophic yeast, Pichia pastoris GS115. An expression yield and specific activity greater than 500 mg/L and 4,000 U/mg was obtained. Results at optimal pH and temperature showed recombinant lysozyme has higher lytic activity at pH 6.5 and $45^{\circ}C$. This study demonstrates the successful expression of recombinant lysozyme using the eukaryotic host organism P. pastoris paving the way for protein engineering. Additionally, this study shows the feasibility of subsequent industrial manufacture of the enzyme with this expression system together with a high purity scheme for easy high-yield purification.

Numerical simulation of infill CACB wall cracking subjected to wind loads

Ruige Li,Yu Gao,Hongjian Lin,Mingfeng Huang,Chenghui Wang,Zhongzhi Hu,Lingyi Jin 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.5

The cracking mechanism in ceramsite aerated concrete block (CACB) infill walls were studied in low seismic fortification intensity coastal areas with frequent occurrence of typhoons. The inter-story drifts of an eight-story residential building under wind loads and a seismic fortification intensity of six degrees were analyzed by using the PKPM software. The maximum inter-story drift ratio of the structure in wind load was found to be comparable to that under the seismic fortification intensity of six degrees. However, when accounting for the large gust wind speed of typhoon, the maximum inter-story drift ratio was much larger than that obtained under reference wind load. In addition, the finite element models of RC frames were employed by displacement loading to simulate two scenarios with and without window hole in the CACB infill walls, respectively. The simulation results show no signs of cracking in both the infill walls with window hole and those without window for the inter-story drift caused by seismic loads and the reference wind load. However, both types of infill walls experienced structural creaking when assessing the gust wind pressure recorded from previous typhoon monitoring. It is concluded that an underestimate of wind loads may contribute substantially to the cracking of frame CACB infill walls in low seismic fortification intensity coastal areas. Consequently, it is imperative to adopt wind pressure values derived from gust wind speeds in the design of CACB infill walls within frame structures. Finally, the future research directions of avoiding cracks in CACB filled walls were proposed. They were the material performance improving and building structure optimizing.

Non-stationary statistical modeling of extreme wind speed series with exposure correction

Huang, Mingfeng,Li, Qiang,Xu, Haiwei,Lou, Wenjuan,Lin, Ning Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.3

Extreme wind speed analysis has been carried out conventionally by assuming the extreme series data is stationary. However, time-varying trends of the extreme wind speed series could be detected at many surface meteorological stations in China. Two main reasons, exposure change and climate change, were provided to explain the temporal trends of daily maximum wind speed and annual maximum wind speed series data, recorded at Hangzhou (China) meteorological station. After making a correction on wind speed series for time varying exposure, it is necessary to perform non-stationary statistical modeling on the corrected extreme wind speed data series in addition to the classical extreme value analysis. The generalized extreme value (GEV) distribution with time-dependent location and scale parameters was selected as a non-stationary model to describe the corrected extreme wind speed series. The obtained non-stationary extreme value models were then used to estimate the non-stationary extreme wind speed quantiles with various mean recurrence intervals (MRIs) considering changing climate, and compared to the corresponding stationary ones with various MRIs for the Hangzhou area in China. The results indicate that the non-stationary property or dependence of extreme wind speed data should be carefully evaluated and reflected in the determination of design wind speeds.

Theoretical Explanation of the Peak Splitting of Tobacco-Specific N-Nitrosamines in HPLC

Jiang, Juxing,Li, Liangchun,Wang, Mingfeng,Xia, Jianjun,Wang, Wenyuan,Xie, Xiaoguang Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.5

During the analyzing processes of the compounds, some researchers are puzzled by the analytical signals for some TSNAs (with or without splitting peaks at various pHs and temperatures). In this work, a detailed theoretical study of structural and thermal properties of the $E/Z$ isomers of TSNAs and the corresponding protonated structures was performed using DFT methods. The calculations showed that the $E$ isomers are almost stable than $Z$ isomers, while the $Z$ isomers would be more stable when in protonation. The calculated results predicted the possibility of separation of their $E$ and $Z$ isomer forms and also showed that protonation affects the dipole moment of molecules significantly (0.1-0.5 to 0.7-2.1 Debye). The calculations agreed well with the experiments that the split-up of the HPLC signal for TSNAs into two peaks are very sensitive to the pH and temperature of the mobile-phase.

Theoretical Explanation of the Peak Splitting of Tobacco-Specific N-Nitrosamines in HPLC

Juxing Jiang,Liangchun Li,Mingfeng Wang,Jianjun Xia,Wenyuan Wang,Xiaoguang Xie 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.5

During the analyzing processes of the compounds, some researchers are puzzled by the analytical signals for some TSNAs (with or without splitting peaks at various pHs and temperatures). In this work, a detailed theoretical study of structural and thermal properties of the E/Z isomers of TSNAs and the corresponding protonated structures was performed using DFT methods. The calculations showed that the E isomers are almost stable than Z isomers, while the Z isomers would be more stable when in protonation. The calculated results predicted the possibility of separation of their E and Z isomer forms and also showed that protonation affects the dipole moment of molecules significantly (0.1-0.5 to 0.7-2.1 Debye). The calculations agreed well with the experiments that the split-up of the HPLC signal for TSNAs into two peaks are very sensitive to the pH and temperature of the mobile-phase.

Research on self-propulsion simulation of a polar ship in a brash ice channel based on body force model

Xie Chang,Zhou Li,Ding Shifeng,Lu Mingfeng,Zhou Xu 대한조선학회 2023 International Journal of Naval Architecture and Oc Vol.15 No.-

Main engine power prediction is important for polar ships operating in brash ice channels, which is one of the most important concerns of shipowners. Self-propulsion simulation is an efficient method to predict the developed power. At present, such models as the discretized propeller model (DPM) and the body force model (BFM) are used for self-propulsion simulation. However, these models are often limited to open water. There is little research on self-propulsion calculations in ice-infested water. This paper presents the BFM to carry out selfpropulsion simulations in a brash ice channel. Research on simulation strategy for open water performance based on the BFM is carried out. Ship–ice–water interactions are simulated using computational fluid dynamicsdiscrete element method (CFD-DEM) coupling method. Both loaded and ballast conditions are considered in the model-scale self-propulsion simulations. Numerical results based on the BFM are compared with the simulation results based on the DPM, as well as model test results. Ship–propeller–ice interactions and propeller suction effects are also compared with photographs taken at an ice tank test. The results show that the differences of the developed power based on the BFM for both loaded and ballast conditions are 8.94% and 15.25%, respectively. The prediction accuracies of the developed power based on the BFM for both loaded and ballast conditions are 1.56% and 7.01%, respectively; lower than those based on the DPM. However, the computation efficiency based on the BFM is 12 times higher than that based on the DPM. To conclude, the proposed BFM could be used as an effective means to calculate the developed power and to evaluate the trend of hull-line optimization at the development stage.

Overexpressing fusion proteins of 4-coumaroyl-CoA ligase (4CL) and stilbene synthase (STS) in tobacco plants leading to resveratrol accumulation and improved stress tolerance

Xuancheng He,Feiyan Xue,Lulu Zhang,Hui-Li Guo,Lan-Qing Ma,Mingfeng Yang 한국식물생명공학회 2018 Plant biotechnology reports Vol.12 No.5

Resveratrol (trans-3,4′,5-trihydroxystilbene) is a phytoalexin produced in plants in response to pathogen attack as a part of plant defense response and it is also a highly bioactive substance of pharmaceutical interest. To obtain transgenic plants with a high level of resveratrol, two enzymes in the last two steps of resveratrol synthesis, 4-coumaroyl-CoA ligase (4CL) and stilbene synthase (STS), were fused together by a glycine–serine–glycine (GSG) tripeptide linker, and the 4CL-GSGSTS construct driven by a CaMV35S promoter was transformed into tobacco (Nicotiana benthamiana) by Agrobacteriummediated method. In the transgenic plants, a high resveratrol level was detected (21.05 μg/g fresh weight) by high-pressure liquid chromatography (HPLC), which is higher than previous transgenic plants with only STS gene overexpression. In addition to resistance to pathogen, transgenic plants showed improved tolerance to salt and osmotic stresses, and the lower level of malondialdehyde (MDA) in transgenic plants suggested that resveratrol could protect plant membrane lipid from peroxidation under abiotic stresses.