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Shi-Tang Ke,Wenlin Yu,Yao-Jun Ge 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.4
In the current code design, the use of a uniform internal pressure coefficient of cooling towers as internal suction cannot reflect the 3D characteristics of flow field inside the tower body with different ventilation rate of shutters. Moreover, extreme weather such as heavy rain also has a direct impact on aerodynamic force on the internal surface and changes the turbulence effect of pulsating wind. In this study, the world\'s tallest cooling tower under construction, which stands 210m, is taken as the research object. The algorithm for two-way coupling between wind and rain is adopted. Simulation of wind field and raindrops is performed iteratively using continuous phase and discrete phase models, respectively, under the general principles of computational fluid dynamics (CFD). Firstly, the rule of influence of 9 combinations of wind speed and rainfall intensity on the volume of wind-driven rain, additional action force of raindrops and equivalent internal pressure coefficient of the tower body is analyzed. The combination of wind velocity and rainfall intensity that is most unfavorable to the cooling tower in terms of distribution of internal pressure coefficient is identified. On this basis, the wind/rain loads, distribution of aerodynamic force and working mechanism of internal pressures of the cooling tower under the most unfavorable working condition are compared between the four ventilation rates of shutters (0%, 15%, 30% and 100%). The results show that the amount of raindrops captured by the internal surface of the tower decreases as the wind velocity increases, and increases along with the rainfall intensity and ventilation rate of the shutters. The maximum value of rain-induced pressure coefficient is 0.013. The research findings lay the basis for determining the precise values of internal surface loads of cooling tower under extreme weather conditions.
Shi-Tang Ke,Hao Wang,Yao-Jun Ge,Lin Zhao,Shuyang Cao 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4
Wind field in mountainous regions demonstrates unique distribution characteristic as compared with the wind field of the flat area, wind load and wind effect are the key considerations in structural design of television towers situated in mountainous regions. The television tower to be constructed is located at the top of Xiushan Mountain in Nanjing, China. In order to investigate the impact of terrain factors of hilltops on wind loads, firstly a wind tunnel test was performed for the mountainous area within 800m from the television tower. Then the tower basal forces such as bending moments and shear strength were obtained based on high frequency force balance (HFFB) test. Based on the experiments, the improved method for determining the load combinations was applied to extract the response distribution patterns of foundation internal force and peak acceleration of the tower top, then the equivalent static wind loads were computed under different wind angles, load conditions and equivalent goals. The impact of terrain factors, damping ratio and equivalent goals on the wind load distribution of a television tower was discussed. Finally the equivalent static wind loads of the television tower under the 5 most adverse wind angles and 5 most adverse load conditions were computed. The experimental method, computations and research findings provide important references for the anti-wind design of high-rise structure built on hilltops.
Shi-Tang Ke,Yifan Dong,Rongkuan Zhu,Tongguang Wang 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.30 No.4
The strong turbulence characteristic of typhoon not only will significantly change flow field characteristics surrounding the large-scale wind turbine and aerodynamic force distribution on surface, but also may cause morphological evolution of coast dune and thereby form sand storms. A 5MW horizontal-axis wind turbine in a wind power plant of southeastern coastal areas in China was chosen to investigate the distribution law of additional loads caused by wind-sand coupling movement of coast dune at landing of strong typhoons. Firstly, a mesoscale Weather Research and Forecasting (WRF) mode was introduced in for high spatial resolution simulation of typhoon “Megi”. Wind speed profile on the boundary layer of typhoon was gained through fitting based on nonlinear least squares and then it was integrated into the user-defined function (UDF) as an entry condition of small-scaled CFD numerical simulation. On this basis, a synchronous iterative modeling of wind field and sand particle combination was carried out by using a continuous phase and discrete phase. Influencing laws of typhoon and normal wind on moving characteristics of sand particles, equivalent pressure distribution mode of structural surface and characteristics of lift resistance coefficient were compared. Results demonstrated that: Compared with normal wind, mesoscale typhoon intensifies the 3D aerodynamic distribution mode on structural surface of wind turbine significantly. Different from wind loads, sand loads mainly impact on 30° ranges at two sides of the lower windward region on the tower. The ratio between sand loads and wind load reaches 3.937% and the maximum sand pressure coefficient is 0.09. The coupling impact effect of strong typhoon and large sand particles is more significant, in which the resistance coefficient of tower is increased by 9.80% to the maximum extent. The maximum resistance coefficient in typhoon field is 13.79% higher than that in the normal wind field.
Band gap opening in zigzag graphene nanoribbon modulated with magnetic atoms
Shi-Hua Tan,Li-Ming Tang,Ke-Qiu Chen 한국물리학회 2014 Current Applied Physics Vol.14 No.11
The effects of magnetic atom on the band structure of zigzag-edged graphene nanoribbons are investigated by the density functional theory. The results show that for narrow zigzag-edged graphene nanoribbons, the band gap can be opened duo to the spin-up/spin-down charges being re-enriched on the edge sites. However, for the wide zigzag-edged graphene nanoribbons, a spin-up/spin-down halfmetallic property can be observed. Moreover, it is found that the Seebeck coefficients in the narrow zigzag-edged graphene nanoribbons are reversed and enlarged, which provides a way to design novel thermoelectric device.
Chinese Patients with Gastric Cancer Need Targeted Adjuvant Chemotherapy Schemes
Shi, Wen-Tao,Wei, Lei,Xiang, Jin,Su, Ke,Ding, Qiong,Tang, Meng-Jie,Li, Ji-Qiang,Guo, Yi,Wang, Pu,Zhang, Jing-Wei Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.10
Background: Gastric cancer (GC) is one of the most common cancers in China. Adjuvant chemotherapy (AC) is a routine auxiliary treatment for GC recommended by the guidelines issued in 2011 by the Ministry of Health of the People's Republic of China, but the relevant credible consequences in China have been insufficient because of China's late start and ethical concerns. Methods: A series of databases, including Cochrane Library, MEDLINE, EMBASE, the Chinese database of the National Knowledge Infrastructure and the VIP database, were searched by 2 reviewers independently for studies investigating AC for GC through March 2012. The retrieved literature was screened according to the eligibility criteria. Results: A total of 35 randomized control trials (RCTs) were subjected to the final analysis, including 4,043 patients in treatment group and 3,884 in the control group, as well as 4 clinical-control trials (CCTs), which accessed the final analysis with 238 and 252 patients, respectively. AC reduced the risk of death as a protective treatment with statistical significance (HR=0.91, 95%CI: [0.85, 0.97], P=0.002), and it seemed more effective for Asian than non-Asian patients. The effects of AC were not influenced by the starting time (P>0.05). D2 lymphadenectomy-based chemotherapy was effective (HR=0.89, 95%CI: [0.80, 0.99], P=0.04). Oral S-1 40 mg/m2 after D2 lymphadenectomy might be a better choice for Asians with advanced GC and might result in a greater reduction of adverse events than in non-Asian patients. GRADE quality assessment determined that the strength of the evidence from foreign studies from Europe, the United States and Asian countries other than China was high, while it was moderate for Chinese studies. Conclusion: AC was effective or even curative in Chinese patients in general, although it is still necessary to optimize a targeted AC scheme for Chinese patients with GC.
Room-temperature tensile strength and thermal shock behavior of spark plasma sintered W-K-TiC alloys
Ke Shi,Bo Huang,Bo He,Ye Xiao,Xiaoliang Yang,Youyun Lian,Xiang Liu,Jun Tang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.1
W-K-TiC alloys with different titanium carbide concentrations (0.05, 0.1, 0.25, 0.5, 1, 2) wt.% werefabricated through Mechanical Alloying and Spark Plasma Sintering. The effects of the addition of nanoscaledTiC particles on the relative density, Vickers micro-hardness, microstructure, crystal information,thermal shock resistance, and tensile strength were investigated. It is revealed that the doped TiC nanoparticleslocated at the grain boundaries. The relative density and Vickers micro-hardness of W-K-TiCalloys was enhanced with TiC addition and the highest Vickers micro-hardness is 731.55. As the TiCaddition increased from 0.05 to 2 wt%, the room-temperature tensile strength raised from 141 to353 MPa. The grain size of the W-K-TiC alloys decreased sharply from 2.56 mm to 330 nm with theenhanced TiC doping. The resistance to thermal shock damage of W-K-TiC alloys was improved slightlywith the increased TiC addition
Haiming Tang,Chao Li,Kaikai Cheng,Lihong Shi,Li Wen,Xiaoping Xiao,Yilan Xu,Weiyan Li,Ke Wang 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.11
Soil physical and chemical characteristics, soil potential denitrification rates (PDR), community composition and nirK-, nirS- and nosZ-encoding denitrifiers were studied by using MiSeq sequencing, quantitative polymerase chain reaction (qPCR), and terminal restriction fragment polymorphism (T-RFLP) technologies base on short-term (5-year) tillage field experiment. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage with crop residue removed as control (RTO). The results indicated that soil organic carbon, total nitrogen and NH4 +-N contents were increased with CT, RT and NT treatments. Compared with RTO treatment, the copies number of nirK, nirS and nosZ in paddy soil with CT, RT and NT treatments were significantly increased. The principal coordinate analysis indicated that tillage management and crop residue returning management were the most and the second important factors for the change of denitrifying bacteria community, respectively. Meanwhile, this study indicated that activity and community composition of denitrifiers with CT, RT and NT treatments were increased, compared with RTO treatment. This result showed that nirK, nirS and nosZ-type denitrifiers communities in crop residue applied soil had higher species diversity compared with crop residue removed soil, and denitrifying bacteria community composition were dominated by Gammaproteobacteria, Deltaproteobacteria, and Betaproteobacteria. Therefore, it is a beneficial practice to increase soil PDR level, abundance and community composition of nitrogen-functional soil microorganism by combined application of tillage with crop residue management.