Emergent constraints on future projections of the western North Pacific Subtropical High

Xiaolong Chen,Tianjun Zhou,Peili Wu,Zhun Guo,Minghuai Wang 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

Study on Properties of Expansive Soil Improved by Steel Slag Powder and Cement under Freeze-Thaw Cycles

Yankai Wu,Xiaolong Qiao,Xinbao Yu,Jiali Yu,Yongfeng Deng 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.2

Expansive soil is considered to be an unfavorable soil due to its swelling-shrinking behavior. In order to improve the properties of expansive soil, the addition of steel slag powder (SSP) has been used to improve expansive soil that has been mixed with the cement. In this study, a series of cylindrical improved expansive soil specimens were prepared, which were improved either by the addition of cement, cement SSP, or cement SSP sodium hydroxide (NaOH). All of the specimens were prepared with an optimum water content and then subjected to a maximum of 12 closed-system freeze-thaw (F-T) cycles. The specimens were subjected to different curing times and temperatures (-5oC,-10oC and -15oC) during the tests. After each freeze-thaw (F-T) cycle, the volume of each specimen was measured and an unconfined compression strength (UCS) test was performed. The results have shown that as the temperature of the F-T cycle decreased, the volume expansion rate increased with the increase of the length of the F-T cycle. As the curing time increased, the effect of the F-T cycles on the volume change rate of the specimens reduced and the UCS increased. The first F-T cycle had the greatest influence on the volume of the specimen as well as the UCS of the improved expansive soil. After the improved expansive soils had undergone more than eight F-T cycles, the volume change rate of the specimen tended to stabilize. The maximum F-T volume change rate of the improved soil was 1.93%.When the curing age was 60d and 90d, the strength of the specimen with cement SSP sodium hydroxide was 377.3 kPa and 294.7 kPa higher than the specimen with cement only (ES specimen), and its strength degradation rate was 18.737% and 9.97% lower than the ES specimen. The results have shown that the addition of SSP and cement improved the expansive soil; moreover, NaOH inhibited the degradation of the soil during an F-T cycle.

Can exercise visual stimulation affect visual spatial attention in a college students?

( Shanshan Wu ),( Hongqing Ji ),( Xiaolong Liu ),( Jung-jun Park ) 대한운동사협회 2017 대한운동사협회 운동사대회자료집 Vol.2017 No.-

C-Band Synthetic Aperture Microwave Radiometer and Its Imaging Experiments

Shengwei, Zhang,Xiaolong, Dong,Ji, Wu,Jingshan, Jiang,Shifeng, Zheng 대한원격탐사학회 2001 International Symposium on Remote Sensing Vol.17 No.1

The principles of the interferometric synthetic aperture was been briefly introduced, the system design of a C-band microwave interferometric synthetic aperture radiometer is presented. This systemhas a 6-element thinned array with 11 analog complex correlator to obtain the 11 visibility function spatial- frequency terns, which result in 22 digitally synthesizedspatial resolution cell. So the synthetic apertureradiometer have a spatial resolution as high as one 22nd of that corresponding to one antenna element. Thesynthetic radiometer has a real aperture resolution cell in the along-hack direction and has 22 synthetic apertureresolution cells in the cross-track direction. Finally, the results of imaging experiments are given.

Identification and co-expression network analysis of plumule-preferentially expressed genes in Oryza sativa

Sun Guilian,Wu Zongmin,Zhai Lisheng,Yi Yin,Yan Huiqing,Huang Xiaolong 한국유전학회 2023 Genes & Genomics Vol.45 No.3

Background The seedling establishment is controlled by the programmed expression of sets of genes at the specific tissues of seed, abundance and environment. Plumule is an important part of the seed embryo and expresses the suits of genes to exert distinct functions during seed germination. Although rice genomic resources are available and developed rapidly, thousands of transcripts have not previously been located in the plumule of rice. Objective This study was performed to identify plumule-preferentially expressed (OsPluP) genes in rice and determine the expression profiles and functions of OsPluP genes. Methods We identified the OsPluP genes through Affymetrix microarray data. Meanwhile, qRT-PCR was performed to validate the expression pattern, also found that OsPluP genes were regulated by dark/light treatment. The cis-acting regulatory elements were analyzed in the promoters’ regions of OsPluP genes. The T-DNA mutant of the OsPluP seed was used to reveal the function in seed germination. Results In this study, a genomic survey of OsPluP genes was performed, and we identified 88 OsPluP genes based on Affymetrix microarray data. The expression profiles of 88 OsPluP members in 24 representative tissues covering rice whole life cycle can be roughly classified into three major groups, suggesting functional divergence of OsPluP genes in seed germination. The microarray data, qRT-PCR, and promoter analysis results demonstrated that transcripts of more than half OsPluPs (54 genes) could be enhanced in the darkness and respond to phytohormone. Gene Ontology (GO)and Kyoto encyclopedia of genes and genomes (KEGG) analysis demonstrated that OsPluP and their co-expressed genes were highly enriched in fatty acid metabolism. Moreover, OsPluP82 T-DNA mutant seeds displayed short plumule length and storage lipid accumulation. Conclusion This study would enable the functions of OsPluP genes during seed germination and contribute to the goal of molecular regulatory networks that lay the foundation for further studies of seedling growth.

Optimal design of a six-axis vibration isolator via Stewart platform by using homogeneous Jacobian matrix formulation based on dual quaternions

Yao Li,XiaoLong Yang,Hongtao Wu,Bai Chen 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

A six-axis vibration isolation system is essential to high-precision space systems for attenuating vibrations on precise instruments. The kinematic optimal design is researched for the space six-axis vibration isolator via Stewart mechanism. Jacobian matrix is the basis of the kinematic performance index. However, the conventional Jacobian matrix is not usually dimensionally homogeneous due to the inhomogeneous physical units, caused by the different mathematical representations of the rotation and translation. In this paper, we propose a dual quaternion approach to derive the dimensionally homogeneous Jacobian matrix of a general six-axis parallel mechanism. Two quaternions are used to parameterize the rotation and translation of the platform. The dimensionally scaling factor for the generalized Jacobian matrix is defined as the ratio of the norms of the two quaternions. The dimensionally homogenous Jacobian matrix is then obtained and applied to the optimal design of the six-axis vibration isolator. The performance index of isotropy is considered to make the isolator minimum kinematic coupling in its working configuration.

Effect of cement as mineral filler on the performance development of emulsified asphalt concrete

Liu, Baoju,Wu, Xiang,Shi, Jinyan,Wu, Xiaolong,Jiang, Junyi,Qin, Jiali Techno-Press 2020 Advances in concrete construction Vol.10 No.6

Cold-mixed asphalt mixture is a widely recommended asphalt pavement materials with potentially economic and environmental benefits. Due to the reduction of natural non-renewable mineral resources, powder minerals with similar properties are considered as new mineral fillers in asphalt mixtures. This study explored the feasibility of using cement to replace natural limestone powder (LP) in emulsified asphalt concrete modified by styrene-butadiene styrene copolymer. The experimental tests, including compressive strength, Marshall stability as well as moisture susceptibility test, were used to investigate the mechanical properties, the Marshall stability, flow value, as well as the moisture damage. In addition, the influence of material composition on the performance of asphalt concrete is explained by the microstructure evolution of the pore structure, the interface transition zone (ITZ), and the micromorphology. Due to mineralogical reactivity of cement, its replacement part of LP improved the mechanical properties, Marshall stability, but it will reduce the moisture susceptibility and flow value. This is because with the increase of the cement substitution rate, the pore structure of the asphalt concrete is refined, the width of ITZ becomes smaller, and the microstructure is more compact. In addition, asphalt concrete with a larger nominal particle size (AC-16) has relatively better performance.

Progressive Collapse Behavior of Large-span Truss String Structures Subjected to Cable Failure

Haiying Zhang,JinYu Lu,Xiaolong Wu,Na Li 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

Cables play an important role in truss string structures, and their sudden failure can lead to massive damage and even collapse of the structures. This paper studies the dynamic response of a 72 m span truss string structure, the progressive collapse numerical simulation of the structure is carried out under different load conditions, the displacement and force responses of the structure after cable failure are investigated, the dynamic amplification factor is calculated, and the collapse mechanism is revealed. The effect of individual factor changes on the structural response is analyzed and compared. Results showed that after cable failure, the stress state of the upper truss changed from an arch to a simply supported beam, when reaching collapse load, the structure collapsed within 5s instead of reaching new equilibrium positions. Moreover, the structure with stiffer elastic support exhibited higher resistance to collapse. The critical member of the truss, which first buckled under compression, shifted from the mid-span to the lower chord at the end, leading to rapid structural collapse. Increasing the cable's cross-sectional area can hardly reduce the structure's dynamic response. However, when the instantaneous failure time of the cable exceeded 0.1s, a significant alleviation of the structure's dynamic response was observed.

Dynamic optimization design of the suspension parameters of car bodymounted equipment via analytical target cascading

Jie Chen,Yangjun Wu,Limin Zhang,Xiaolong He,Shijie Dong 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.5

Under dynamic conditions, the dynamic force between the suspended equipment and the car body is substantially increased. This increase not only affects the ride comfort but also substantially raises the likelihood of fatigue damage to the suspended equipment. A multiobjective analytical target cascading (ATC) optimization is proposed to improve the ride comfort of high-speed trains and reduce the vibration of the suspended equipment. A mathematical simulation model of the vehicle equipment system is established, and the acceleration frequency-response function expression of the car body and the suspension system is obtained. The comfort index of the car body and the acceleration root mean square (RMS) of the suspended equipment are calculated by combining the German vertical irregular track spectrum and the comfort filter function. Meanwhile, the ATC method is used to optimize the car body comfort index and the acceleration RMS of the underframe suspended equipment. Then, the availability of the optimization method is evaluated via numerical simulation. Compared with the original suspension scheme of the underframe equipment, when the running speed of the vehicle is 300 km/h, the RMS value of the vibrational acceleration of the underframe equipment after optimization decreases by 19.9 %, and the ride comfort indexes at the car body center and above the front and rear bogies are improved by 6.4 %, 0.1 %, and 1.1 %, respectively. Simulation results demonstrate that ATC optimization can improve the railway vehicle ride comfort and reduce the vibration of the suspended equipment. This paper provides a new approach to the suspension parameter design of equipment.

Operation optimization of auxiliary electric boiler system in HTR-PM nuclear power plant

Du Xingxuan,Ma Xiaolong,Liu Junfeng,Wu Shifa,Wang Pengfei 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

Electric boilers (EBs) are the backup steam source for the auxiliary steam system of high-temperature gas-cooled reactor nuclear power plants. When the plant is in normal operations, the EB is always in hot standby status. However, the current hot standby operation strategy has problems of slow response, high power consumption, and long operation time. To solve these problems, this study focuses on the optimization of hot standby operations for the EB system. First, mathematical models of an electrode immersion EB and its accompanying deaerator were established. Then, a control simulation platform of the EB system was developed in MATLAB/Simulink implementing the established mathematical models and corresponding control systems. Finally, two optimization strategies for the EB hot standby operation were proposed, followed by dynamic simulations of the EB system transient from hot standby to normal operations. The results indicate that the proposed optimization strategies can significantly speed up the transient response of the EB system from hot standby to normal operations and reduce the power consumption in hot standby operations, improving the dynamic performance and economy of the system.