Numerical simulation of unsteady propeller force for a submarine in straight ahead sailing and steady diving maneuver

Yu-cun Pan,Huai-xin Zhang,Qi-dou Zhou 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

In order to provide a complementary perspective to the effects of the maneuvering motions on the unsteady propeller performance, the numerical simulation of the flow field of the hull-rudder- propeller system is performed by Unsteady Reynolds-averaged Naiver-Stokes (URANS) method. Firstly, the flow fields around the submarine model without the presence of propeller in straight ahead motion and the steady diving maneuvers with submergence rudder deflections of 4, 8 and 12 are predicted numerically. The non-uniformity characteristic of the nominal wake field is exacerbated with the increase of submergence rudder angle. Then the flow field around the SUBOFF-G submarine fitted with the 4381 propeller is simulated. The axial, transverse and vertical unsteady propeller forces in different maneuvering conditions are compared. In general, as the submarine maneuvers more violently, the harmonic amplitudes of the unsteady force at the 2BPF and 3BPF increased more significantly than that at BPF.

Adaptive Learning Path Recommendation based on Graph Theory and an Improved Immune Algorithm

( Cun-ling Bian ),( De-liang Wang ),( Shi-yu Liu ),( Wei-gang Lu ),( Jun-yu Dong ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.5

Adaptive learning in e-learning has garnered researchers’ interest. In it, learning resources could be recommended automatically to achieve a personalized learning experience. There are various ways to realize it. One of the realistic ways is adaptive learning path recommendation, in which learning resources are provided according to learners’ requirements. This paper summarizes existing works and proposes an innovative approach. Firstly, a learner-centred concept map is created using graph theory based on the features of the learners and concepts. Then, the approach generates a linear concept sequence from the concept map using the proposed traversal algorithm. Finally, Learning Objects (LOs), which are the smallest concrete units that make up a learning path, are organized based on the concept sequences. In order to realize this step, we model it as a multi-objective combinatorial optimization problem, and an improved immune algorithm (IIA) is proposed to solve it. In the experimental stage, a series of simulated experiments are conducted on nine datasets with different levels of complexity. The results show that the proposed algorithm increases the computational efficiency and effectiveness. Moreover, an empirical study is carried out to validate the proposed approach from a pedagogical view. Compared with a self-selection based approach and the other evolutionary algorithm based approaches, the proposed approach produces better outcomes in terms of learners’ homework, final exam grades and satisfaction.

Numerical simulation of unsteady propeller force for a submarine in straight ahead sailing and steady diving maneuver

Pan, Yu-cun,Zhang, Huai-xin,Zhou, Qi-dou The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

In order to provide a complementary perspective to the effects of the maneuvering motions on the unsteady propeller performance, the numerical simulation of the flow field of the hull-rudder- propeller system is performed by Unsteady Reynolds-averaged Naiver-Stokes (URANS) method. Firstly, the flow fields around the submarine model without the presence of propeller in straight ahead motion and the steady diving maneuvers with submergence rudder deflections of 4°, 8° and 12° are predicted numerically. The non-uniformity characteristic of the nominal wake field is exacerbated with the increase submergence rudder angle. Then the flow field around the SUBOFF-G submarine fitted with the 4381 propeller is simulated. The axial, transverse and vertical unsteady propeller forces in different maneuvering conditions are compared. In general, as the submarine maneuvers more violently, the harmonic amplitudes of the unsteady force at the 2BPF and 3BPF increased more significantly than that at BPF.

Burmese Sentiment Analysis Based on Transfer Learning

Cunli Mao,Zhibo Man,Zhengtao Yu,Xia Wu,Haoyuan Liang 한국정보처리학회 2022 Journal of information processing systems Vol.18 No.4

Using a rich resource language to classify sentiments in a language with few resources is a popular subject ofresearch in natural language processing. Burmese is a low-resource language. In light of the scarcity of labeledtraining data for sentiment classification in Burmese, in this study, we propose a method of transfer learningfor sentiment analysis of a language that uses the feature transfer technique on sentiments in English. Thismethod generates a cross-language word-embedding representation of Burmese vocabulary to map Burmesetext to the semantic space of English text. A model to classify sentiments in English is then pre-trained using aconvolutional neural network and an attention mechanism, where the network shares the model for sentimentanalysis of English. The parameters of the network layer are used to learn the cross-language features of thesentiments, which are then transferred to the model to classify sentiments in Burmese. Finally, the model wastuned using the labeled Burmese data. The results of the experiments show that the proposed method cansignificantly improve the classification of sentiments in Burmese compared to a model trained using only aBurmese corpus.

Expression of Fas/FasL in CD8⁺ T and CD3⁺ Foxp3⁺ Treg Cells - Relationship with Apoptosis of Circulating CD8⁺ T Cells in Hepatocellular Carcinoma Patients

Guo, Cun-Li,Yang, Xiu-Hua,Cheng, Wen,Xu, Yi,Li, Jie-Bing,Sun, Yi-Xin,Bi, Yu-Mei,Zhang, Lei,Wang, Qiu-Cheng Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Aims: Dysfunction of the host immune system in cancer patients can be due to a number of factors, including lymphocyte apoptosis. Several studies showed that $Foxp3^+T$ cells take part in inducing this process by expressing FasL in tumor patients. However, the relationship between apoptosis, $CD8^+T$ cells and $Foxp3^+T$ cells in HCC patients is still unclear. The present study was designed to investigate the correlation between apoptosis levels and Fas/FasL expression in $CD8^+T$ lymphocytes and $Foxp3^+T$ cells in patients with HCC. Methods: $CD8^+T$ cells and $CD3^+Foxp3^+T$ cells were tested from peripheral blood of HCC patients and normal controls and subjected to multicolor flow cytometry. The expression of an apoptosis marker (annexin V) and the death receptor Fas in $CD8^+T$ cells and FasL in $CD3^+Foxp3^+T$ cells were evaluated. Serum TGF-${\beta}1$ levels in patients with HCC were measured by enzyme-linked immunosorbent assay. The relationship between apoptosis and Fas expression, as well as FasL expression in $CD3^+Foxp3^+T$ cells was then evaluated. Results: The frequency of $CD8^+T$ cells binding annexin V and Fas expression in $CD8^+T$ cells, were all higher in HCC patients than normal controls and the proportion of apoptotic $CD8^+T$ cells correlated with their Fas expression. Serum TGF-${\beta}1$ levels correlated inversely with $CD3^+Foxp3^+T$ cells. Conclusions: Fas/FasL interactions might lead to excessive turnover of $CD8^+T$ cells and reduce anti-tumor immune responses in patients with HCC. Further investigations of apoptosis induction in $Fas^+CD8^+T$ cells in vitro are required.

Study on the Relationship Between CXCR4 Expression and Perineural Invasion in Pancreatic Cancer

Jiang, Yu-Mei,Li, Guang,Sun, Bao-Cun,Zhao, Xiu-Lan,Zhou, Zhong-Kai Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Background: Recent reports have shown that C-X-C chemokine receptor 4 (CXCR4) plays an important role in metastasis. Despite a clear understanding of the protein's structure and properties, its functional role remains elusive. We conducted the present study to evaluate the expressions of CXCR4 in pancreatic cancer, and to investigate its relationship with clinicopathological parameters, especially perineural invasion(PNI). Materials and Methods: The association between CXCR4 expression and perineural invasion was determined by immunohistochemistry in pancreatic cancer patients (n=51). Results: CXCR4 expression was correlated with the existence of PNI and the type of PNI (p=0.042, p=0.040). TIMP-2 expression was also correlated with the existence, the pathway and degree of PNI (p=0.000, p=0.006, p=0.000). Conclusions: Our results suggest an association between PNI and expression of CXCR4 and TIMP-2 in pancreatic cancer. CXCR4 may promote the occurrence of PNI in pancreatic cancer cells by decreasing the inhibition of TIMPs on MMP.

The dilatancy and numerical simulation of failure behavior of granular materials based on Cosserat model

Chu, Xihua,Yu, Cun,Xu, Yuanjie Techno-Press 2012 Interaction and multiscale mechanics Vol.5 No.2

The dilatancy of granular materials has significant influence on its mechanical behaviors. The dilation angle is taken as a constant in conventional associated or non-associated flow rules based on Drucker-Prager yields theory. However, various experimental results show the dilatancy changes during progressive failure of granular materials. A non-associated flow rule with evolution of dilation angle is adopted in this study, and Cosserat continuum theory is used to describe the behaviors of granular materials for considering to some extent the its internal structure. Numerical examples focus on the bearing capacity and localization of granular materials, and results illustrate the capability and performance of the presented model in modeling the effect on failure behavior of granular materials.

Two scale modeling of behaviors of granular structure: size effects and displacement fluctuations of discrete particle assembly

Xihua Chu,Cun Yu,Chenxi Xiu,Yuanjie Xu 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.2

This study’s primary aim is to check the existence of a representative volume element for granular materials and determine the link between the properties (responses) of macro structures and the size of the discrete particle assembly used to represent a constitutive relation in a two-scale model. In our two-scale method the boundary value problem on the macro level was solved using finite element method, based on the Cosserat continuum; the macro stresses and modulus were obtained using a solution of discrete particle assemblies at certain element integration points. Meanwhile, discrete particle assemblies were solved using discrete element method under boundary conditions provided by the macro deformation. Our investigations focused largely on the size effects of the discrete particle assembly and the radius of the particle on macro properties, such as deformation stiffness, bearing capacity and the residual strength of the granular structure. According to the numerical results, we suggest fitting formulas linking the values of different macro properties (responses) and size of discrete particle assemblies. In addition, this study also concerns the configuration and displacement fluctuation of discrete particle assemblies on the micro level, accompanied with the evolution of bearing capacity and deformation on the macro level.

NATURE AND CATALYTIC PERFORMANCE OF PtSAPO-5 MOLECULAR SIEVE CATALYST SYNTHESIZED BY ONE STEP

Xiao, Tian cun,Wang, Hai tao,Lu, Yu li,An, Li dun,Wang, Hong li 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.5

Pt catalysts supported on silicoaluminophosphate molecular sieves were synthesized by adding platinum salts directly to the gel mixture of SAPO. The synthesized products were marked as PtSAPO-5, in order to distinguish with the SAPO-5 supported platinum catalyst prepared by impregnation, which was marked as Pt/SAPO-5. The as-synthesized and calcined PtSAPO-5 samples were characterized by XRD, ^(29)Si MAS NMR, ^(129)Xe NMR and NH₃-TPD, and their catalytic activities were evaluated by the, hydroisomerization of n-hexane. The results revealed that in PtSAPO-5, the platinum could catalyze the removal of the templates entrapped in the as-synthesized samples. The presence of Pt in the gel mixture can increase silicon content in the framework of SAPO-5, and the acid sites. In the activated PtSAPO-5 catalyst, Pt was highly dispersed in the channel of SAPO-5 molecular sieve. Pt exists in the form of big particles outside of the channel of Pt/SAPO-5 prepared by impregnating method, and impregnation with H₂PtCl_6 improved the strength of acid sites. PtSAPO-5 has a higher activity and selectivity than Pk/SAPO-5 in the hydroisomerization of n-hexane. This is because the former has medium acid sites and high dispersion of Pt, while the channel of Pt/SAPO-5 is somewhat retarded by the big platinum particles, and the acid sites are stronger than the former.

PKM2 Regulates Hepatocellular Carcinoma Cell Epithelial-mesenchymal Transition and Migration upon EGFR Activation

Fan, Fang-Tian,Shen, Cun-Si,Tao, Li,Tian, Chao,Liu, Zhao-Guo,Zhu, Zhi-Jie,Liu, Yu-Ping,Pei, Chang-Song,Wu, Hong-Yan,Zhang, Lei,Wang, Ai-Yun,Zheng, Shi-Zhong,Huang, Shi-Le,Lu, Yin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Pyruvate kinase isozyme type M2 (PKM2) was first found in hepatocellular carcinoma (HCC), and its expression has been thought to correlate with prognosis. A large number of studies have demonstrated that epithelial-mesenchymal transition (EMT) is a crucial event in hepatocellular carcinoma (HCC) and associated metastasis, resulting in enhanced malignancy of HCC. However, the roles of PKM2 in HCC EMT and metastasis remain largely unknown. The present study aimed to determine the effects of PKM2 in EGF-induced HCC EMT and elucidate the molecular mechanisms in vitro. Our results showed that EGF promoted EMT in HCC cell lines as evidenced by altered morphology, expression of EMT-associated markers, and enhanced invasion capacity. Furthermore, the present study also revealed that nuclear translocation of PKM2, which is regulated by the ERK pathway, regulated ${\beta}$-catenin-TCF/LEF-1 transcriptional activity and associated EMT in HCC cell lines. These discoveries provide evidence of novel roles of PKM2 in the progression of HCC and potential therapeutic target for advanced cases.