Dynamics of high-speed train in crosswinds based on an air-train-track interaction model

Zhai, Wanming,Yang, Jizhong,Li, Zhen,Han, Haiyan Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.

Atrial fibrillation in critically ill patients who received prolonged mechanical ventilation: a nationwide inpatient report

( Zhen Lin ),( Hedong Han ),( Wei Guo ),( Xin Wei ),( Zhijian Guo ),( Shujie Zhai ),( Shuai Li ),( Yiming Ruan ),( Fangyuan Hu ),( Dongdong Li ),( Jia He ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.6

Background/Aims: To evaluate temporal trends of atrial fibrillation (AF) prevalence in critically ill patients who received prolonged mechanical ventilation (MV) in the United States. Methods: We used the 2008 to 2014 National Inpatient Sample to compute the weighted prevalence of AF among hospitalized adult patients on prolonged MV. We used multivariable-adjusted models to evaluate the association of AF with clinical factors, in-hospital mortality, hospitalization cost, and length of stay (LOS). Results: We identified 2,578,165 patients who received prolonged MV (21.27% of AF patients). The prevalence of AF increased from 14.63% in 2008 to 24.43% in 2014 (p for trend < 0.0001). Amongst different phenotypes of critically ill patients, the prevalence of AF increased in patients with severe sepsis, asthma exacerbation, congestive heart failure exacerbation, acute stroke, and cardiac arrest. Older age, male sex, white race, medicare access, higher income, urban teaching hospital setting, and Western region were associated with a higher prevalence of AF. AF in critical illness was a risk factor for in-hospital death (odds ratio, 1.13; 95% confidence interval, 1.11 to 1.15), but in-hospital mortality in critically ill patients with AF decreased from 11.6% to 8.3%. AF was linked to prolonged LOS (2%, p < 0.0001) and high hospitalization cost (4%, p < 0.0001). LOS (-1%, p < 0.0001) and hospitalization cost (-4%, p < 0.0001) decreased yearly. Conclusions: The prevalence of comorbid AF is increasing, particularly in older patients. AF may lead to poorer prognosis, and high-quality intensive care is imperative for this population.

Dynamics of high-speed train in crosswinds based on an air-train-track interaction model

Wanming Zhai,Jizhong Yang,Zhen Li,Haiyan Han 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2

A numerical model for analyzing airtraintrack interaction is proposed to investigate thedynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of atraintrack interaction model and a trainair interaction model. The traintrack interaction model is built onthe basis of the vehicletrack coupled dynamics theory. The trainair interaction model is developed basedon the train aerodynamics, in which the Arbitrary LagrangianEulerian (ALE) method is employed to dealwith the dynamic boundary between the train and the air. Based on the airtraintrack model, characteristicsof flow structure around a high-speed train are described and the dynamic behavior of the high-speed trainrunning on track in crosswinds is investigated. Results show that the dynamic indices of the head car arelarger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the runningsafety of the train in crosswinds is basically controlled by the head car. Compared with the generally usedassessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio,the overturning coefficient will overestimate the running safety of a train on a track under crosswindcondition. It is suggested to use the wheel-load reduction ratio and the lateral wheelrail force as thedominant safety assessment indices when high-speed trains run in crosswinds.

Ab initio MRCI+Q Investigations of Spectroscopic Properties of Several Low-lying Electronic States of S₂⁺ Cation

Li, Rui,Zhai, Zhen,Zhang, Xiaomei,Liu, Tao,Jin, Mingxing,Xu, Haifeng,Yan, Bing Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.5

The complete active space self-consist field method followed by the internally contracted multireference configuration interaction method has been used to compute the potential energy curves of $X^2\prod_g$, $a^4\prod_u$, $A^2\prod_u$, $b^4\sum_{g}^{-}$, and $B^2\sum_{g}^{-}$ states of $S{_2}^+$ cation with large correlation-consistent basis sets. Utilizing the potential energy curves computed with different basis sets, the spectroscopic parameters of these states were evaluated. Finally, the transition dipole moment and the Franck-Condon factors of the transition from $A^2\prod_u$ to $X^2\prod_g$ were evaluated. The radiative lifetime of $A^2\prod_u$ is calculated to be 887 ns, which is in good agreement with experimental value of $805{\pm}10$ ns.

Ab initio MRCI+Q Investigations of Spectroscopic Properties of Several Low-lying Electronic States of S2+ Cation

Rui Li,Zhen Zhai,Xiaomei Zhang,Tao Liu,Mingxing Jin,Haifeng Xu,Bing Yan 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.5

The complete active space self-consist field method followed by the internally contracted multireference configuration interaction method has been used to compute the potential energy curves of X2Πg, a4Πu, A2Πu, b4Σ− g, and B2Σ− g states of S2 + cation with large correlation-consistent basis sets. Utilizing the potential energy curves computed with different basis sets, the spectroscopic parameters of these states were evaluated. Finally, the transition dipole moment and the Franck-Condon factors of the transition from A2Πu to X2Πg were evaluated. The radiative lifetime of A2Πu is calculated to be 887 ns, which is in good agreement with experimental value of 805 ± 10 ns.

Numerical investigation on the wave interferences of submerged bodies operating near the free surface

Li Dong,Yang Qun,Zhai Lin,Wang Zhen,He Chuan-lin 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

A key factor that governs the wave interferences of a submerged body is the dimensionless Froude number. Computational Fluid Dynamics (CFD) is used to describe the resistance force coefficients and the generated waves of two SUBOFF submarine models. Grid independence studies are performed on two cases, totally and shallowly submerged cases, with four sets of computing meshes. The highest peaks are marked by red points at given wavelengths, a line is fitted to those points with a least-squares approximation, and the half wake angle at multiple Froude numbers is defined between the fitted line and the centerline of the free surface. The results show that when the depth of the target is 1.1D, constructive interferences occur at Fn ¼ 0.3 and 0.5, while destructive interference occurs at Fn ¼ 0.35 with distortion of the waveform. The half wake angle is less than 19.47 because of the interference between the bow and stern wave systems.

Evaluation of the YOLO models for discrimination of the alfalfa pollinating bee species

Zhang Chuan-Jie,Liu Teng,Wang Jinxu,Zhai Danlan,Zhang Youxin,Gao Yang,Wu Hui-Zhen,Yu Jialin,Chen Min 한국응용곤충학회 2024 Journal of Asia-Pacific Entomology Vol.27 No.1

Identifying insect pollinators and their roles in mediating pollen flow is critical to understand the potential gene flow risks of insect pollination-dependent crop species, such as alfalfa. This study was conducted to evaluate and compare the feasibility of You Only Look Once (YOLO) version 3 (YOLOv3), YOLOv5, YOLOv7, and YOLO Representation (YOLOR) to discriminate the three most common alfalfa pollinating bee species, including honeybee, bumblebee, and leafcutting bee. The metrics comparison results showed YOLOv3 and YOLOv5 out performed YOLOv7 and YOLOR regarding model precision, recall, F 1 score, and mAP50 values. YOLOv3 and YOLOv5 could successfully discriminate the three different bee species with an accuracy of almost 100% (99.9%, 99.8%, and 100% accuracy for honeybee, bumblebee, and leafcutting bee for the two models, respectively). Comparatively, YOLOv7 could discriminate honeybee with an accuracy of 95% but was more likely to mistakenly discriminate bumblebee and leafcutting bee due to the relatively lower discriminating accuracy (87.3% and 66.2%, respectively). While the values of determined parameters for YOLOR were lower than YOLOv3 and YOLOv5, the higher precision (0.99680) along with recall (0.98721), F 1 (0.99198), mAP50 (0.99323), and mAP50-100 (0.89076) values indicate that this model could be able to obtain a favorable performance in discriminating the three bee species. In summary, the proposed method in this study has the potential for identifying the alfalfa pollinating bee species, studying the bees’ flower-visiting behaviors, evaluating the risks of insect-mediated pollen flow, and thus contributing to the management of genetically engineered (GE) alfalfa transgene flow.

PLCE1 Gene in Esophageal Cancer and Interaction with Environmental Factors

Guo, Li-Yan,Zhang, Shen,Suo, Zhen,Yang, Chang-Shuang,Zhao, Xia,Zhang, Guo-An,Hu, Die,Ji, Xing-Zhao,Zhai, Min Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.7

Objective: To study the PLCE1 gene rs2274223 polymorphism with regard to esophageal cancer and its interaction with diet, lifestyle, psychological and environmental factors in Southwest Shandong province. Materials and Methods: A case series study (case-case) was conducted. Questionnaire data were collected and 3 ml-5ml venous blood was drawn for DNA extraction among the qualified research subjects. PLCE1 gene polymorphism was detected after PCR amplification of DNA. SPSS 13.0 software was used for statistical analysis of the data. Results: The three genotypes A/A, A/G and G/G PLCE1 gene rs2274223 was 31, 16 and 4 cases, accounting for 60.8%, 31.4%, 0.08% respectively. The difference of three genotypes (AA/GA/GG) proportion between negative and positive family history of patients was statistically significant, ${\chi}^2=6.213$, p=0.045. There was no statistically significant relationship between PLCE1 gene rs2274223 polymorphism and smoking, drinking, ${\chi}^2=0.119$, p=0.998, and ${\chi}^2=1.727$, p=0.786. There was no linkage of the three rs2274223 PLCE1 gene genotypes (AA/GA/GG) proportion with eating fried, pickled, hot, mildew, overnight, smoked, excitant food, eat speed, salt taste or not (p>0.05). or with living environment pollution and nine risk factors of occupational exposure (p>0.05). There was no statistically significant difference in TS scores between different genotype of rs2274223 PLCE1 gene. Conclusions: The PLCE1 rs2274223 polymorphism has a relationship with family history of esophageal cancer, but does not have any significant association with age, gender, smoking, alcohol drinking, food hygiene, eating habits, living around the environment and occupation in cases.

Microwave-assisted Solvent-free Synthesis of Some Dimethine Cyanine Dyes, Spectral Properties and TD-DFT/PCM Calculations

Zhang, Xiang-Han,Wang, Lan-Ying,Zhai, Gao-Hong,Wen, Zhen-Yi,Zhang, Zu-Xun Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.12

A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by 1H NMR, IR, UV-Vis spectra and elemental analysis. The absorption and fluorescence properties of these dyes were investigated both experimentally and theoretically. Calculations performed at a combination of time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) reproduced the π-π* type absorption bands of the dyes. Regression analysis was used for studying theoretical results of the absorption maxima in different solvents. Compared with experimental counterparts, estimated overall uncertainties in the absorption maxima were about ±2%.

Microwave-assisted Solvent-free Synthesis of Some Dimethine Cyanine Dyes, Spectral Properties and TD-DFT/PCM Calculations

Xiang-Han Zhang,Lan-Ying Wang*,Gao-Hong Zhai,Zhen-Yi Wen,Zu-Xun Zhang 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.12

A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by 1H NMR, IR, UV-Vis spectra and elemental analysis. The absorption and fluorescence properties of these dyes were investigated both experimentally and theoretically. Calculations performed at a combination of time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) reproduced the p-p* type absorption bands of the dyes. Regression analysis was used for studying theoretical results of the absorption maxima in different solvents. Compared with experimental counterparts, estimated overall uncertainties in the absorption maxima were about ?2%.