Optimization of Duct Shape for Improving Aerodynamic Performance of Ducted Tail Rotor

Chenkai Cao,Bo Wang,Guoqing Zhao,Qijun Zhao 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.2

Numerical simulations on the aerodynamics of helicopter ducted tail rotor in hover are conducted, and a surrogate-based optimization framework is employed for the duct shape design in this work, by considering interactions between rotor and duct. The CFD analyses of ducted tail rotor are performed using the helicopter code CLORNS, including the momentum source method and high-fidelity CFD methods. The SA365N1 Dauphin fenestron in a test case is simulated by CFD methods and the duct shape is selected as baseline design for optimization. Parametric researches are conducted to investigate the relationship between the aerodynamic loads of ducted tail rotor and the variations of duct shape. Besides, the influence of duct shape on the flow details of rotor blade is obtained by resolving the flowfield based on high-fidelity CFD, and detailed analyses of the flow separation phenomenon downstream the rotor with large collective pitches are presented. Then, the multi-optimization of duct shape with different collective pitches is conducted by employing a surrogate-based optimization framework. Compared with the baseline design, the hovering efficiency of optimized design is improved because of a better negative pressure distribution on the duct wall.

Parametric study on the rotor blade of Helicopter ducted tail rotor by using high-fidelity CFD methods

Chenkai Cao,Guoqing Zhao,Qijun Zhao 한국전산유체공학회 2022 한국전산유체공학회 학술대회논문집 Vol.2022 No.10

An Innovative Rotor Position Detection at Stand-Still and Low Speed with Carrier Phase-Shifted PWM Method

Kewang Qu,Guoqing Xu,차석원,Yanhui Zhang,Wei Feng,Junci Cao,Weili Li,Yihuang Zhang,Zhigang Wu 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.9

An innovative permanent magnet synchronous motor rotor position detection method using d-q reference-frames derived from PWM inverter switching is presented based on carrier phase-shift PWM method. It also gives the development the polarity identification at standstill for permanent magnet synchronies motor in the rotary frame with position detected of the neutral voltage. The new technique detects the motor position from simple measurements of the neutral point voltage of the motor influenced by the variation of inductances with respect to rotor position. The transfer is derived with constant element and 2nd harmonic element of selfinductance and mutual-inductance between three phase inductances and the inductance of d-axis and q-axis. Theoretical studies are carried out and verified using experiment results with variation rotor position over one electrical cycle at standstill. Rotor position estimation from stator inductance variation with rotor position is effective in zero speed and low speed.

Analysis of Aerodynamic Characteristics of Rotor Near Water Surface

Fan Yang,Guoqing Zhao,Xi Chen,Qijun Zhao,Chenkai Cao 한국전산유체공학회 2022 한국전산유체공학회 학술대회논문집 Vol.2022 No.10

Estimation of Genetic and Phenotypic Covariance Functions for Body Weight as Longitudinal Data of SD-II Swine Line

Liu, Wenzhong,Cao, Guoqing,Zhou, Zhongxiao,Zhang, Guixian Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.5

Growth records over six generations of 686 pigs in SD-II Swine Line were used to estimate the genetic and phenotypic covariance functions for body weight as longitudinal data. A random regression model with Legendre polynomials of age as independent variables was used to estimate the (co)variances among the regression coefficients, thus the coefficients of genetic and permanent environmental covariance functions by restricted maximum likelihood employing the average information algorithm. The results showed that, using litter effect as additional random effect, a reduced order of fit did not describe the data adequately. For all five orders of fit, however, the change trends of genetic and phenotypic (co)variances were very similar from ${\kappa}$=3 onwards.

Axial Compression Performance of Reinforced Concrete Columns after Lateral Impact Load

Haoxiang Luan,Jin Wu,Tianbao Cao,Xing Zhao,Fei Geng,Guoqing Dong 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

Axial compression performance and bearing capacity of reinforced concrete column is crucial to concrete structure. Lateral Impact load could pose severe danger to the security and service life of reinforced concrete column. Impact dynamic response, axial compression performanceand residual bearing capacity of reinforced concrete columns after lateral impact load were investigated in this paper. Investigation results indicated that with the increase of impact energy, residual displacement and crack width on column increased, impact damage on column exacerbated. It was proved that impact resistance performance of reinforced concrete column could be enhanced by preload axial force. Residual bearing capacity of reinforced concrete column degenerated obviously after subjected to lateral impact load. And RC column would be under elastic stage when impact energy was low. According to analysis results on the correlation between residual displacement and residual bearing capacity, prediction model on residual bearing capacity of reinforced concrete column after lateral impact load was proposed.

Novel splice isoforms of pig myoneurin and their diverse mRNA expression patterns

Guo, Xiaohong,Li, Meng,Gao, Pengfei,Cao, Guoqing,Cheng, Zhimin,Zhang, Wanfeng,Liu, Jianfeng,Liu, Xiaojun,Li, Bugao Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.10

Objective: The aim of this study was to clone alternative splicing isoforms of pig myoneurin (MYNN), predict the structure and function of coding protein, and study temporal and spatial expression characteristics of each transcript. Methods: Alternative splice isoforms of MYNN were identified using RNA sequencing (RNA-seq) and cloning techniques. Quantitative real-time polymerase chain reaction (qPCR) was employed to detect expression patterns in 11 tissues of Large White (LW) and Mashen (MS) pigs, and to study developmental expression patterns in cerebellum (CE), stomach (ST), and longissimus dorsi (LD). Results: The results showed that MYNN had two alternatively spliced isoforms, MYNN-1 (GenBank accession number: KY470829) and MYNN-2 (GenBank accession number: KY670835). MYNN-1 coding sequence (CDS) is composed of 1,830 bp encoding 609 AA, whereas MYNN-2 CDS is composed of 1,746 bp encoding 581 AA. MYNN-2 was 84 bp less than MYNN-1 and lacked the sixth exon. MYNN-2 was found to have one $C_2H_2$ type zinc finger protein domain less than MYNN-1. Two variants were ubiquitously expressed in all pig tissues, and there were significant differences in expression of different tissues (p<0.05; p<0.01). The expression of MYNN-1 was significantly higher than that of MYNN-2 in almost tissues (p<0.05; p<0.01), which testified that MYNN-1 is the main variant. The expression of two isoforms decreased gradually with increase of age in ST and CE of MS pig, whereas increased gradually in LW pig. In LD, the expression of two isoforms increased first and then decreased with increase of age in MS pig, and decreased gradually in LW pig. Conclusion: Two transcripts of pig MYNN were successfully cloned and MYNN-1 was main variant. MYNN was highly expressed in ST, CE, and LD, and their expression was regular. We speculated that MYNN plays important roles in digestion/absorption and skeletal muscle growth, whereas the specific mechanisms require further elucidation.

Selection of candidate genes affecting meat quality and preliminary exploration of related molecular mechanisms in the Mashen pig

Pengfei Gao,Zhimin Cheng,Meng Li,Ningfang Zhang,Baoyu Le,Wanfeng Zhang,Pengkang Song,Xiaohong Guo,Bugao Li,Guoqing Cao 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.8

Objective: The aim of this study was to select the candidate genes affecting meat quality and preliminarily explore the related molecular mechanisms in the Mashen pig. Methods: The present study explored genetic factors affecting meat quality in the Mashen pig using RNA sequencing (RNA-Seq). We sequenced the transcriptomes of 180-day-old Mashen and Large White pigs using longissimus dorsi to select differentially expressed genes (DEGs). Results: The results indicated that a total of 425 genes were differentially expressed between Mashen and Large White pigs. A gene ontology enrichment analysis revealed that DEGs were mainly enriched for biological processes associated with metabolism and muscle development, while a Kyoto encyclopedia of genes and genomes analysis showed that DEGs mainly participated in signaling pathways associated with amino acid metabolism, fatty acid metabolism, and skeletal muscle differentiation. A MCODE analysis of the protein-protein interaction network indicated that the four identified subsets of genes were mainly associated with translational initiation, skeletal muscle differentiation, amino acid metabolism, and oxidative phosphorylation pathways. Conclusion: Based on the analysis results, we selected glutamic-oxaloacetic transaminase 1, malate dehydrogenase 1, pyruvate dehydrogenase 1, pyruvate dehydrogenase kinase 4, and activator protein-1 as candidate genes affecting meat quality in pigs. A discussion of the related molecular mechanisms is provided to offer a theoretical basis for future studies on the improvement of meat quality in pigs.

Glutamic-oxaloacetic transaminase 1 regulates adipocyte differentiation by altering nicotinamide adenine dinucleotide phosphate content

Yang Yang,Cheng Zhimin,Zhang Wanfeng,Hei Wei,Lu Chang,Cai Chunbo,Zhao Yan,Gao Pengfei,Guo Xiaohong,Cao Guoqing,Li Bugao 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.2

Objective: This study was performed to examine whether the porcine glutamic-oxaloacetic transaminase 1 (GOT1) gene has important functions in regulating adipocyte differentiation. Methods: Porcine GOT1 knockout and overexpression vectors were constructed and transfected into the mouse adipogenic 3T3-L1 cells. Lipid droplets levels were measured after 8 days of differentiation. The mechanisms through which GOT1 participated in lipid deposition were examined by measuring the expression of malate dehydrogenase 1 (MDH1) and malic enzyme (ME1) and the cellular nicotinamide adenine dinucleotide phosphate (NADPH) content. Results: GOT1 knockout significantly decreased lipid deposition in the 3T3-L1 cells (p< 0.01), whereas GOT1 overexpression significantly increased lipid accumulation (p<0.01). At the same time, GOT1 knockout significantly decreased the NADPH content and the expression of MDH1 and ME1 in the 3T3-L1 cells. Overexpression of GOT1 significantly increased the NADPH content and the expression of MDH1 and ME1, suggesting that GOT1 regulated adipocyte differentiation by altering the NADPH content. Conclusion: The results preliminarily revealed the effector mechanisms of GOT1 in regulating adipose differentiation. Thus, a theoretical basis is provided for improving the quality of pork and studies on diseases associated with lipid metabolism. Objective: This study was performed to examine whether the porcine glutamic-oxaloacetic transaminase 1 (GOT1) gene has important functions in regulating adipocyte differentiation.Methods: Porcine GOT1 knockout and overexpression vectors were constructed and transfected into the mouse adipogenic 3T3-L1 cells. Lipid droplets levels were measured after 8 days of differentiation. The mechanisms through which GOT1 participated in lipid deposition were examined by measuring the expression of malate dehydrogenase 1 (MDH1) and malic enzyme (ME1) and the cellular nicotinamide adenine dinucleotide phosphate (NADPH) content.Results: GOT1 knockout significantly decreased lipid deposition in the 3T3-L1 cells (p<0.01), whereas GOT1 overexpression significantly increased lipid accumulation (p<0.01). At the same time, GOT1 knockout significantly decreased the NADPH content and the expression of MDH1 and ME1 in the 3T3-L1 cells. Overexpression of GOT1 significantly increased the NADPH content and the expression of MDH1 and ME1, suggesting that GOT1 regulated adipocyte differentiation by altering the NADPH content.Conclusion: The results preliminarily revealed the effector mechanisms of GOT1 in regulating adipose differentiation. Thus, a theoretical basis is provided for improving the quality of pork and studies on diseases associated with lipid metabolism.

Long non-coding RNAs in Sus scrofa ileum under starvation stress

Wang Shu,Ma Yi Jia,Li Yong Shi,Ge Xu Sheng,Lu Chang,Cai Chunbo,Yang Yang,Zhao Yan,Liang Guo Ming,Guo Xiaohong,Cao Guoqing,Li Bugao,Gao Pengfei 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.7

Objective: In this study, we aimed to identify long non-coding RNAs (lncRNAs) that play important roles in starvation stress, analyze their functions, and discover potential molecular targets to alleviate starvation stress to provide a theoretical reference for subsequent in-depth research. Methods: We generated a piglet starvation stress animal model. Nine Yorkshire weaned piglets were randomly divided into a long-term starvation stress group (starved for 72 h), short-term starvation stress group (starved for 48 h), and the control group. LncRNA libraries were constructed using high-throughput sequencing of piglet ileums. Results: We obtained 11,792 lncRNAs, among which, 2,500 lncRNAs were novel. In total, 509 differentially expressed (DE)lncRNAs were identified in this study. Target genes of DElncRNAs were predicted via cis and trans interactions, and functional and pathway analyses were performed. Gene ontology functions and Kyoto encyclopedia of genes and genomes analysis revealed that lncRNA-targeted genes mainly participated in metabolic pathways, cellular processes, immune system processes, digestive systems, and transport activities. To reveal the mechanism underlying starvation stress, the interaction network between lncRNAs and their targets was constructed based on 26 DElncRNAs and 72 DEmRNAs. We performed an interaction network analysis of 121 DElncRNA–DEmRNA pairs with a Pearson correlation coefficient greater than 0.99. Conclusion: We found that MSTRG.19894.13, MSTRG.16726.3, and MSTRG.12176.1 might play important roles in starvation stress. This study not only generated a library of enriched lncRNAs in piglets, but its outcomes also provide a strong foundation to screen key lncRNAs involved in starvation stress and a reference for subsequent in-depth research. Objective: In this study, we aimed to identify long non-coding RNAs (lncRNAs) that play important roles in starvation stress, analyze their functions, and discover potential molecular targets to alleviate starvation stress to provide a theoretical reference for subsequent in-depth research.Methods: We generated a piglet starvation stress animal model. Nine Yorkshire weaned piglets were randomly divided into a long-term starvation stress group (starved for 72 h), short-term starvation stress group (starved for 48 h), and the control group. LncRNA libraries were constructed using high-throughput sequencing of piglet ileums.Results: We obtained 11,792 lncRNAs, among which, 2,500 lncRNAs were novel. In total, 509 differentially expressed (DE)lncRNAs were identified in this study. Target genes of DElncRNAs were predicted via cis and trans interactions, and functional and pathway analyses were performed. Gene ontology functions and Kyoto encyclopedia of genes and genomes analysis revealed that lncRNA-targeted genes mainly participated in metabolic pathways, cellular processes, immune system processes, digestive systems, and transport activities. To reveal the mechanism underlying starvation stress, the interaction network between lncRNAs and their targets was constructed based on 26 DElncRNAs and 72 DEmRNAs. We performed an interaction network analysis of 121 DElncRNA–DEmRNA pairs with a Pearson correlation coefficient greater than 0.99.Conclusion: We found that MSTRG.19894.13, MSTRG.16726.3, and MSTRG.12176.1 might play important roles in starvation stress. This study not only generated a library of enriched lncRNAs in piglets, but its outcomes also provide a strong foundation to screen key lncRNAs involved in starvation stress and a reference for subsequent in-depth research.