Effect of External Heat Input on Fluid Sloshing Dynamic Performance in a Liquid Oxygen Tank

Liu Zhan,Feng Yuyang,Liu Yuanliang,Yan Jia,Li Yanzhong 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.4

In the present study, a numerical model is developed to research the effect of the heat input on fluid sloshing. The volume of fluid method is used to simulate fluid reciprocating motion during sloshing with the mesh motion treatment being coupled. The external sloshing excitation is realized by user-defined functions and the convection thermal boundary condition is adopted to consider the heat exchange between the tank and the external environment. The model validation is made with the relative error being less than five percent. Based on the developed numerical model, the variation of fluid pressure, interface fluctuation, fluid sloshing hydrodynamics and fluid temperature distribution are, respectively, analyzed. Some conclusions are obtained finally. The present study is significant to the fluid sloshing suppression in cryogenic fuel storage tanks.

A comparison of the diagnostic performance of the O-RADS, RMI4, IOTA LR2, and IOTA SR systems by senior and junior doctors

Yuyang Guo,Baihua Zhao,Shan Zhou,Lieming Wen,Liu Jieyu,Yaqian Fu,Fang Xu,Minghui Liu 대한초음파의학회 2022 ULTRASONOGRAPHY Vol.41 No.3

Purpose: This study compared the diagnostic performance of the Ovarian-Adnexal Reporting and Data System (O-RADS), the Risk of Malignancy Index 4 (RMI4), the International Ovarian of Tumor Analysis Logistic Regression Model 2 (IOTA LR2), and the IOTA Simple Rules (IOTA SR) in predicting the malignancy of adnexal masses (AMs).Methods: This retrospective study included 575 women with AMs between 2017 and 2020. All clinical messages, ultrasound images, and pathological findings were collected. Two senior doctors (group I) and two junior doctors (group II) used the four systems to classify AMs. The postoperative pathological diagnosis was used as the gold standard to evaluate the diagnostic efficiency. A receiver operating characteristic curve was used to test the diagnostic performance. The interrater agreement between the two groups was tested using kappa values.Results: Of all 592 AMs, 447 (75.5%) were benign, 123 (20.8%) were malignant, and 22 (3.7%) were borderline. The intergroup consistency test yielded kappa values of 0.71, 0.92, 0.68, and 0.77 for the O-RADS, RMI4, IOTA LR2, and IOTA SR, respectively. To predict malignant lesions, the areas under the curve of the O-RADS, RMI4, IOTA LR2, and IOTA SR systems were 0.90, 0.89, 0.90, and 0.86 for group I and 0.89, 0.87, 0.88, and 0.84 for group II, respectively. The O-RADS had the highest sensitivity (91.0% in group I and 84.8% in group II).Conclusion: The four diagnostic systems could compensate for junior doctors’ inexperience in predicting malignant adnexal lesions. The O-RADS performed best and showed the highest sensitivity.

Exploring the Impact of Real-Time Feedback on Archery Performance and Training Efficiency

( Yuyang Liu ),( Seunghee Lee ) 한국감성과학회 2023 한국감성과학회 국제학술대회(ICES) Vol.2023 No.-

Archery, a sport requiring precise muscle coordination, traditionally relies on extensive practice for skill enhancement. Recent advancements use motion sensor, heart rate sensor, electromyographic sensor, and cameras to evaluate performance. This study introduces a real-time accuracy feedback system to improve motor-cognitive coordination and reduce the training time needed for beginners. Two groups― one with attention-based reminder devices and one without―were compared based on target score standard deviations algorithm scores for posture stability, and NASA-TLX scores for attention load in a pilot study. Future works concern improving the algorithm, device development, and designing feedback to encourage self-triggered releases. This study provides the groundwork for future experiments focused on enhancing archery training using the stability indicator device.

Study on Magnetic Force Calculation of Spherical Permanent Magnets

Yuyang Zhang,Yonggang Leng,Dan Tan,Jinjun Liu Korean Magnetics Society 2018 Journal of Magnetics Vol.23 No.4

This paper presents three approaches to calculate the interacting magnetic force about spherical permanent magnet, respectively based on magnetic dipole-dipole model, equivalent magnetic charge model and equivalent magnetizing current model. We use all of three models to fully calculate and study the behaviors of lateral and axial forces with respect to the related positions between a pair of spherical magnets. The accuracies of the calculation results are compared with the experimental data. In conclusion, the magnetic dipole-dipole model has the most advantageous accuracy and efficiency for the magnetic force calculation about spherical permanent magnets on account of the particularity of sphere. Our study provides an important criterion for choosing a proper method to calculate magnetic force about spherical permanent magnet.

Comparison of Magnetic Force Calculation on Permanent Magnets with Models of Equivalent Magnetic Charge and Magnetizing Current

Yuyang Zhang,Yonggang Leng,Jinjun Liu,Dan Tan 한국자기학회 2019 Journal of Magnetics Vol.24 No.3

Accurate magnetic force calculation is essential to effectively analyzing a system or device containing magnets. Among several approaches used in the interacting magnetic force calculation of permanent magnets, equivalent magnetic charge and equivalent magnetizing current models are widely adopted. In this paper, we choose cubes and cylinders as calculating objects to investigate the detailed calculation procedures. Higher calculation accuracy of the equivalent magnetizing current model is verified by comparison between simulation and experiment results. Furthermore, we analyze the relations between two models and discriminate their equivalence in the magnetic force calculation respectively at both micro and macro scale. Reference basis for choosing a proper model to calculate magnetic force is provided in this work, which is beneficial for the design of electro-mechanical structures with permanent magnets.

A general methodology for simulation model validation and model updating of the coordination mechanism with uncertainty

Taisu Liu,Yuyang Niu,Guangsong Chen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

In order to improve the accuracy and credibility of the dynamic simulation model of the coordination mechanism, a general simulation model validation and updating framework was proposed. First, the dynamic model of the coordination mechanism was established considering two friction models. Then, in order to validate the accuracy of the simulation model, for the high-dimensional uncertainty, a validation method of the coordination simulation model based on principal component analysis-area index was proposed. Aiming at the problem that the simulation model was unreliable, a simulation model updating method based on parameter identification was proposed. Finally, the correctness and effectiveness of the method were verified, and the result showed that the accuracy of the simulation updating model with identified LuGre friction model was improved by 31.03 % than the one with identified Coulomb friction model. Thus, the accuracy and credibility of the coordination mechanism simulation model were greatly improved. It provides a theoretical support for the simulation model validation & updating of the coordination mechanism and other mechanical mechanisms.

The learning curve and difficult points of the O-RADS ultrasound risk stratification system in 54 trainees

Shan Zhou,Yuyang Guo,Lieming Wen,Baihua Zhao,Minghui Liu 대한초음파의학회 2022 ULTRASONOGRAPHY Vol.41 No.2

Purpose: This study aimed to evaluate the learning curve and explore the difficult points of the Ovarian-Adnexal Reporting and Data System (O-RADS) ultrasound risk stratification system.Methods: One hundred adnexal masses (AMs) were randomly selected for five tests as training data. Two experienced trainers had an inter-rater agreement of 0.95 for the O-RADS scores. Fifty-four trainees (26 level I practitioners [group 1], 17 level II practitioners [group 2], and 11 experienced level II practitioners [group 3]) attended the training. Every trainee received assessment and feedback after 20 scored cases. The outcomes of the five tests were compared among the three groups using repeated-measurements analysis of variance.Results: Of the 100 AMs, 52 were pathologically benign and 48 were malignant; the O-RADS scores were 2, 3, 4, and 5 in 22, 11, 48, and 19 AMs, respectively. The between-subjects effects test showed no significant differences between groups 1, 2, and 3 for the five tests (P=0.501). For each group, the differences among the five tests were significant (P<0.001, P=0.006, and P=0.044 for groups 1, 2, and 3, respectively). Test 2 was the worst. In 23 cases, more than 40% of trainees gave incorrect answers, which mainly related to classic benign lesions, the color flow score, and solid-appearing masses.Conclusion: After training, junior doctors at different levels can reach a coincident O-RADS ultrasound risk stratification. The difficulties primarily related to subjective judgments of classic benign lesions, the color flow score, and solid-appearing masses. More experience is needed to improve the applicability of the system.

Influence of wheat-walnut intercropping on the Sitobion avenae and its predatory natural enemies

Gao Haifeng,Jia Shuangshuang,Liu Yongqiang,Shen Yuyang,Li Guangkuo,Zhao Sifeng,Ge Feng 한국응용곤충학회 2024 Journal of Asia-Pacific Entomology Vol.27 No.1

Intercropping is widely applied all over the world, and it often causes significant changes in the number of arthropod communities. Walnut-wheat intercropping systems are commonly applied in Southern Xinjiang of China. But it is still not clear how wheat-walnut intercropping influence pest and natural enemy populations, and their ratio in wheat fields. To clarify this question and provide guidance to pest management, field surveys were conducted in Xinjiang during 2017–2019. Three intercropping treatments were tested, which were wheat-walnut 10:6, 25:6, and monoculture wheat. Our results showed that the abundance of predators (mainly ladybeetles and lacewings) increased in wheat under wheat-walnut intercropping systems (especially in intercrop treatment 10:6). Compared with monoculture wheat, the ratio of predators to Sitobion avenae was not enhanced in wheatwalnut intercropping fields. S. avenae populations increased in the walnut intercropped wheat fields. The intercropping system was not beneficial to S. avenae control in wheat fields. Different measures should be taken to strengthen the control of S. avenae in walnut intercropped wheat fields.

A Study on the Formation Mechanism and Calculation Method of Surrounding Rock Pressure in Shallow-buried Loess Tunnel Considering the Influence of Vertical Joints

Mingkun Zhao,Hongpeng Lai,Yuyang Liu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

Vertical joints have significant effects on the stability of shallow-buried loess tunnel. Due to the presence of vertical joints distributed widely in loess, the formation mechanisms of surrounding rock pressure on shallow-buried loess tunnel and its computational method are far different from those in other types of soil tunnel. In this study, the distribution characteristics of surrounding rock pressure in shallow-buried loess tunnel were investigated, and discrete element software 3DEC was used to analyze the formation mechanism and development process of surrounding rock pressure in loess tunnel under the influence of joints. We correlated the stratum deformation characteristic with the frictional force caused by the mutual dislocation between joints, and revised the semi-empirical method (Chinese Code methods) in China. The results show that the measured data of radial surrounding rock pressure of shallow-buried loess tunnel are generally between 0 − 600 kPa, and 80% in the range of 0 − 200 kPa. The surrounding rock pressure increases with the burial depth, while the distribution of lateral pressure coefficient is relatively discrete. The existence of loess vertical joints (LVJs) aggravates the uneven distribution of the vertical pressure above the tunnel, and the reduction of the lateral earth pressure coefficient at rest under the influence of joints leads to an increase in pressure near the arch shoulder, these two constitute the essence of the joints action on the surrounding rock pressure. The surrounding rock pressure of the shallow-buried loess tunnel reaches the peak stress at about 0.5D from the tunnel face (D is the tunnel span), which is about 1.04 − 1.32 times of the initial stress. After the excavation of the upper step, the stress of the tunnel crown monitoring point decreased to about 60% of the initial stress. Compared with ignoring the influence of joints, the time of reaching the peak stress at the arch shoulder monitoring point is earlier, and the final stress release degree is smaller. The comparison of the analytical results (proposed method) with the numerical results and the field data exhibits good agreement, proving the proposed method's correctness.

Improved Agrobacterium tumefaciens-mediated transformation using antibiotics and acetosyringone selection in cucumber

Du Changxia,Chai Li’ang,Liu Chen,Yuyang Si,Fan Huaifu 한국식물생명공학회 2022 Plant biotechnology reports Vol.16 No.1

Cucumber (Cucumis sativus) is one of the most important vegetable crop species in the world. As conventional breeding of cucumber is very challenging, genetic engineering is an alternative option for introducing important traits such as enhanced stress resistance and nutritional value. However, the efficiency of the transformation system depends on genotypes, transfor- mation conditions, etc. This study aims to optimize the transformation parameters of Agrobacterium-mediated transformation of cucumber. ‘Xintaimici’, which is a very popular and typical northern Chinese cucumber variety, was transformed with Agrobacterium GV3101. The strain carried the pCAMBIA2300s plasmid, which is a binary vector containing the marker gene neomycin phosphotransferase II (npt II). The results indicated that cefotaxime sodium was suitable for inhibiting Agrobacterium in the screening and bud elongation stages. Timentin was best used during the rooting stage. Furthermore, 25 mg/L kanamycin was used in the early stage of screening and increased to 50 mg/L for further screening. At the bud elongation and rooting stages, 75 and 100 mg/L kanamycin was used, respectively, to improve the screening efficiency. To obtain the highest regeneration frequency of resistant buds, 50, 150, and 100 μM acetosyringone was added to the preculture medium, infection solution, and coculture medium, respectively. To confirm the presence of the transgenes, DNA from npt II transformed cucumber plants was analyzed by polymerase chain reaction after transplanting resistant regenerated plants. We ultimately achieved an 8.1% transformation efficiency, which is among the highest values reported to date using the cucumber variety ‘Xintaimici’. Thus, an effective protocol for Agrobacterium tumefaciens-mediated genetic transformation of cucumber was optimized.