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Granular behaviour under bi-directional shear with constant vertical stress and constant volume 被引量:1
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作者 Min Zhang Yunming Yang +1 位作者 Hanwen Zhang Qi Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4300-4318,共19页
This paper aims to investigate the role of bi-directional shear in the mechanical behaviour of granular materials and macro-micro relations by conducting experiments and discrete element method(DEM)modelling.The bi-di... This paper aims to investigate the role of bi-directional shear in the mechanical behaviour of granular materials and macro-micro relations by conducting experiments and discrete element method(DEM)modelling.The bi-directional shear consists of a static shear consolidation and subsequent shear under constant vertical stress and constant volume conditions.A side wall node loading method is used to exert bi-directional shear of various angles.The results show that bi-directional shear can significantly influence the mechanical behaviour of granular materials.However,the relationship between bidirectional shear and mechanical responses relies on loading conditions,i.e.constant vertical stress or constant volume conditions.The stress states induced by static shear consolidation are affected by loading angles,which are enlarged by subsequent shear,consistent with the relationship between bidirectional shear and principal stresses.It provides evidence for the dissipation of stresses accompanying static liquefaction of granular materials.The presence of bi-directional principal stress rotation(PSR)is demonstrated,which evidences why the bi-directional shear of loading angles with components in two directions results in faster dissipations of stresses with static liquefaction.Contant volume shearing leads to cross-anisotropic stress and fabric at micro-contacts,but constant vertical stress shearing leads to complete anisotropic stress and fabric at micro-contacts.It explains the differentiating relationship between stress-strain responses and fabric anisotropy under these two conditions.Micromechanical signatures such as the slip state of micro-contacts and coordination number are also examined,providing further insights into understanding granular behaviour under bi-directional shear. 展开更多
关键词 Granular material bi-directional shear Constant vertical stress Constant volume Principal stress rotation(PSR) ANISOTROPY
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Application of CFD and FEA Coupling to Predict Structural Dynamic Responses of A Trimaran in Uni-and Bi-Directional Waves
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作者 LIAO Xi-yu XIA Jin-song +4 位作者 CHEN Zhan-yang TANG Qin ZHAO Nan ZHAO Wei-dong GUI Hong-bin 《China Ocean Engineering》 SCIE EI CSCD 2024年第1期81-92,共12页
To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing... To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be obtained.Firstly,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step schemes.Discussion on the wave elevation of uni-and bi-directional waves is also carried out.Then a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,respectively.Finally,the differences in structural response characteristics of trimaran in different wave fields are studied.The results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations. 展开更多
关键词 CFD-FEA fluid-structure coupling structural responses TRIMARAN bi-directional cross sea
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Properties and Stability of Max-Product Fuzzy Bi-Directional Associative Memory 被引量:2
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作者 舒兰 《Journal of Electronic Science and Technology of China》 2005年第2期175-177,共3页
In this paper, a fuzzy operator of max-product is defined at first, and the fuzzy bi-directional associative memory (FBAM) based on the fuzzy operator of max-product is given. Then the properties and the Lyapunov stab... In this paper, a fuzzy operator of max-product is defined at first, and the fuzzy bi-directional associative memory (FBAM) based on the fuzzy operator of max-product is given. Then the properties and the Lyapunov stability of equilibriums of the networks are studied. 展开更多
关键词 fuzzy operator of max-product max-product fuzzy bi-directional associative memory fuzzy Hebb code EQUILIBRIUM Lyapunov stability
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A chaotic hierarchical encryption/watermark embedding scheme for multi-medical images based on row-column confusion and closed-loop bi-directional diffusion
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作者 张哲祎 牟俊 +1 位作者 Santo Banerjee 曹颖鸿 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期228-237,共10页
Security during remote transmission has been an important concern for researchers in recent years.In this paper,a hierarchical encryption multi-image encryption scheme for people with different security levels is desi... Security during remote transmission has been an important concern for researchers in recent years.In this paper,a hierarchical encryption multi-image encryption scheme for people with different security levels is designed,and a multiimage encryption(MIE)algorithm with row and column confusion and closed-loop bi-directional diffusion is adopted in the paper.While ensuring secure communication of medical image information,people with different security levels have different levels of decryption keys,and differentiated visual effects can be obtained by using the strong sensitivity of chaotic keys.The highest security level can obtain decrypted images without watermarks,and at the same time,patient information and copyright attribution can be verified by obtaining watermark images.The experimental results show that the scheme is sufficiently secure as an MIE scheme with visualized differences and the encryption and decryption efficiency is significantly improved compared to other works. 展开更多
关键词 chaotic hierarchical encryption multi-medical image encryption differentiated visual effects row-column confusion closed-loop bi-directional diffusion transform domain watermark embedding
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Device-Free Through-the-Wall Activity Recognition Using Bi-Directional Long Short-Term Memory and WiFi Channel State Information
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作者 Zi-Yuan Gong Xiang Lu +2 位作者 Yu-Xuan Liu Huan-Huan Hou Rui Zhou 《Journal of Electronic Science and Technology》 CAS CSCD 2021年第4期357-368,共12页
Activity recognition plays a key role in health management and security.Traditional approaches are based on vision or wearables,which only work under the line of sight(LOS)or require the targets to carry dedicated dev... Activity recognition plays a key role in health management and security.Traditional approaches are based on vision or wearables,which only work under the line of sight(LOS)or require the targets to carry dedicated devices.As human bodies and their movements have influences on WiFi propagation,this paper proposes the recognition of human activities by analyzing the channel state information(CSI)from the WiFi physical layer.The method requires only the commodity:WiFi transmitters and receivers that can operate through a wall,under LOS and non-line of sight(NLOS),while the targets are not required to carry dedicated devices.After collecting CSI,the discrete wavelet transform is applied to reduce the noise,followed by outlier detection based on the local outlier factor to extract the activity segment.Activity recognition is fulfilled by using the bi-directional long short-term memory that takes the sequential features into consideration.Experiments in through-the-wall environments achieve recognition accuracy>95%for six common activities,such as standing up,squatting down,walking,running,jumping,and falling,outperforming existing work in this field. 展开更多
关键词 Activity recognition bi-directional long short-term memory(Bi-LSTM) channel state information(CSI) device-free through-the-wall.
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The complex roles of m^(6)A modifications in neural stem cell proliferation, differentiation, and self-renewal and implications for memory and neurodegenerative diseases
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作者 Yanxi Li Jing Xue +8 位作者 Yuejia Ma Ke Ye Xue Zhao Fangliang Ge Feifei Zheng Lulu Liu Xu Gao Dayong Wang Qing Xia 《Neural Regeneration Research》 SCIE CAS 2025年第6期1582-1598,共17页
N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis a... N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis and neural regeneration, where it is highly concentrated and actively involved in these processes. Changes in m^(6)A modification levels and the expression levels of related enzymatic proteins can lead to neurological dysfunction and contribute to the development of neurological diseases. Furthermore, the proliferation and differentiation of neural stem cells, as well as nerve regeneration, are intimately linked to memory function and neurodegenerative diseases. This paper presents a comprehensive review of the roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, as well as its implications in memory and neurodegenerative diseases. m^(6)A has demonstrated divergent effects on the proliferation and differentiation of neural stem cells. These observed contradictions may arise from the time-specific nature of m^(6)A and its differential impact on neural stem cells across various stages of development. Similarly, the diverse effects of m^(6)A on distinct types of memory could be attributed to the involvement of specific brain regions in memory formation and recall. Inconsistencies in m^(6)A levels across different models of neurodegenerative disease, particularly Alzheimer's disease and Parkinson's disease, suggest that these disparities are linked to variations in the affected brain regions. Notably, the opposing changes in m^(6)A levels observed in Parkinson's disease models exposed to manganese compared to normal Parkinson's disease models further underscore the complexity of m^(6)A's role in neurodegenerative processes. The roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, and its implications in memory and neurodegenerative diseases, appear contradictory. These inconsistencies may be attributed to the timespecific nature of m^(6)A and its varying effects on distinct brain regions and in different environments. 展开更多
关键词 Alzheimer's disease cell self-renewal central nervous system memory MICROGLIA nerve regeneration neurodegenerative diseases NEUROGENESIS RNA methylation
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Exercise preconditioning alleviates ischemia-induced memory deficits by increasing circulating adiponectin
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作者 Meifeng Zheng Borui Zhang +3 位作者 Sonata S Y Yau Kwok-Fai So Li Zhang Haining Ou 《Neural Regeneration Research》 SCIE CAS 2025年第5期1445-1454,共10页
Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug therapy.Physical exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitatio... Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug therapy.Physical exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after stroke.In this study,we determined whether exercise training before disease onset can alleviate the severity of cerebral ischemia.We also examined the role of exercise-induced circulating factors in these effects.Adult mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery occlusion.We found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory function.Further analysis showed that circulating adiponectin plays a critical role in these preventive effects of exercise.Agonist activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise effects.In summary,our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise. 展开更多
关键词 ADIPONECTIN cerebral ischemia exercise pre-conditioning HIPPOCAMPUS memory function middle cerebral artery occlusion prefrontal cortex synaptic proteins treadmill exercise
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Recombinant chitinase-3-like protein 1 alleviates learning and memory impairments via M2 microglia polarization in postoperative cognitive dysfunction mice
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作者 Yujia Liu Xue Han +6 位作者 Yan Su Yiming Zhou Minhui Xu Jiyan Xu Zhengliang Ma Xiaoping Gu Tianjiao Xia 《Neural Regeneration Research》 SCIE CAS 2025年第9期2727-2736,共10页
Postoperative cognitive dysfunction is a seve re complication of the central nervous system that occurs after anesthesia and surgery,and has received attention for its high incidence and effect on the quality of life ... Postoperative cognitive dysfunction is a seve re complication of the central nervous system that occurs after anesthesia and surgery,and has received attention for its high incidence and effect on the quality of life of patients.To date,there are no viable treatment options for postoperative cognitive dysfunction.The identification of postoperative cognitive dysfunction hub genes could provide new research directions and therapeutic targets for future research.To identify the signaling mechanisms contributing to postoperative cognitive dysfunction,we first conducted Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of the Gene Expression Omnibus GSE95426 dataset,which consists of mRNAs and long non-coding RNAs differentially expressed in mouse hippocampus3 days after tibial fracture.The dataset was enriched in genes associated with the biological process"regulation of immune cells,"of which Chill was identified as a hub gene.Therefore,we investigated the contribution of chitinase-3-like protein 1 protein expression changes to postoperative cognitive dysfunction in the mouse model of tibial fractu re surgery.Mice were intraperitoneally injected with vehicle or recombinant chitinase-3-like protein 124 hours post-surgery,and the injection groups were compared with untreated control mice for learning and memory capacities using the Y-maze and fear conditioning tests.In addition,protein expression levels of proinflammatory factors(interleukin-1βand inducible nitric oxide synthase),M2-type macrophage markers(CD206 and arginase-1),and cognition-related proteins(brain-derived neurotropic factor and phosphorylated NMDA receptor subunit NR2B)were measured in hippocampus by western blotting.Treatment with recombinant chitinase-3-like protein 1 prevented surgery-induced cognitive impairment,downregulated interleukin-1βand nducible nitric oxide synthase expression,and upregulated CD206,arginase-1,pNR2B,and brain-derived neurotropic factor expression compared with vehicle treatment.Intraperitoneal administration of the specific ERK inhibitor PD98059 diminished the effects of recombinant chitinase-3-like protein 1.Collectively,our findings suggest that recombinant chitinase-3-like protein 1 ameliorates surgery-induced cognitive decline by attenuating neuroinflammation via M2 microglial polarization in the hippocampus.Therefore,recombinant chitinase-3-like protein1 may have therapeutic potential fo r postoperative cognitive dysfunction. 展开更多
关键词 Chil1 hippocampus learning and memory M2 microglia NEUROINFLAMMATION postoperative cognitive dysfunction(POCD) recombinant CHI3L1
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Regulator of G protein signaling 6 mediates exercise-induced recovery of hippocampal neurogenesis,learning,and memory in a mouse model of Alzheimer’s disease
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作者 Mackenzie M.Spicer Jianqi Yang +5 位作者 Daniel Fu Alison N.DeVore Marisol Lauffer Nilufer S.Atasoy Deniz Atasoy Rory A.Fisher 《Neural Regeneration Research》 SCIE CAS 2025年第10期2969-2981,共13页
Hippocampal neuronal loss causes cognitive dysfunction in Alzheimer’s disease.Adult hippocampal neurogenesis is reduced in patients with Alzheimer’s disease.Exercise stimulates adult hippocampal neurogenesis in rode... Hippocampal neuronal loss causes cognitive dysfunction in Alzheimer’s disease.Adult hippocampal neurogenesis is reduced in patients with Alzheimer’s disease.Exercise stimulates adult hippocampal neurogenesis in rodents and improves memory and slows cognitive decline in patients with Alzheimer’s disease.However,the molecular pathways for exercise-induced adult hippocampal neurogenesis and improved cognition in Alzheimer’s disease are poorly understood.Recently,regulator of G protein signaling 6(RGS6)was identified as the mediator of voluntary running-induced adult hippocampal neurogenesis in mice.Here,we generated novel RGS6fl/fl;APP_(SWE) mice and used retroviral approaches to examine the impact of RGS6 deletion from dentate gyrus neuronal progenitor cells on voluntary running-induced adult hippocampal neurogenesis and cognition in an amyloid-based Alzheimer’s disease mouse model.We found that voluntary running in APP_(SWE) mice restored their hippocampal cognitive impairments to that of control mice.This cognitive rescue was abolished by RGS6 deletion in dentate gyrus neuronal progenitor cells,which also abolished running-mediated increases in adult hippocampal neurogenesis.Adult hippocampal neurogenesis was reduced in sedentary APP_(SWE) mice versus control mice,with basal adult hippocampal neurogenesis reduced by RGS6 deletion in dentate gyrus neural precursor cells.RGS6 was expressed in neurons within the dentate gyrus of patients with Alzheimer’s disease with significant loss of these RGS6-expressing neurons.Thus,RGS6 mediated voluntary running-induced rescue of impaired cognition and adult hippocampal neurogenesis in APP_(SWE) mice,identifying RGS6 in dentate gyrus neural precursor cells as a possible therapeutic target in Alzheimer’s disease. 展开更多
关键词 adult hippocampal neurogenesis Alzheimer’s disease dentate gyrus EXERCISE learning/memory neural precursor cells regulator of G protein signaling 6(RGS6)
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Pilot Study of Molecular Mechanism on Vasculogenic Mimicry in Bi-directional Differentiated Malignant Tumors 被引量:2
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作者 孙保存 张诗武 +2 位作者 赵秀兰 张丹芳 郝希山 《The Chinese-German Journal of Clinical Oncology》 CAS 2005年第1期50-52,68,共4页
Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction ... Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction differential malignant tumor specimens withparaffin-embedded were enrolled into our study and made tissue microarray which were dual-stainedwith CD31-PAS and stained with collagen IV. The difference of the areas and distribution withpattern surrounded by between CD31 and PAS positive respectively were identified via grid-counting,as well as the difference of VEGF expression with VE absent and present. Results: The basementmembrane of VM was both PAS and collagen IV positive. VEGF expression in the bi-directiondifferential malignant tumor was higher VM-absent than VM-present and the difference wasstatistically significance in malignant melanoma and alveolar rhabdomyosarcoma (P 【 0.05).Conclusion: PAS positive substance and collagen IV compose the wall of VE and VE could provide theoxygen and nutrition for tumor growth and progression. 展开更多
关键词 bi-direction differential malignant tumor vasculogenic mimicry dual-staining tissue microarray
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Multi-agent system application in accordance with game theory in bi-directional coordination network model 被引量:3
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作者 ZHANG Jie WANG Gang +3 位作者 YUE Shaohua SONG Yafei LIU Jiayi YAO Xiaoqiang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第2期279-289,共11页
The multi-agent system is the optimal solution to complex intelligent problems. In accordance with the game theory, the concept of loyalty is introduced to analyze the relationship between agents' individual incom... The multi-agent system is the optimal solution to complex intelligent problems. In accordance with the game theory, the concept of loyalty is introduced to analyze the relationship between agents' individual income and global benefits and build the logical architecture of the multi-agent system. Besides, to verify the feasibility of the method, the cyclic neural network is optimized, the bi-directional coordination network is built as the training network for deep learning, and specific training scenes are simulated as the training background. After a certain number of training iterations, the model can learn simple strategies autonomously. Also,as the training time increases, the complexity of learning strategies rises gradually. Strategies such as obstacle avoidance, firepower distribution and collaborative cover are adopted to demonstrate the achievability of the model. The model is verified to be realizable by the examples of obstacle avoidance, fire distribution and cooperative cover. Under the same resource background, the model exhibits better convergence than other deep learning training networks, and it is not easy to fall into the local endless loop.Furthermore, the ability of the learning strategy is stronger than that of the training model based on rules, which is of great practical values. 展开更多
关键词 LOYALTY GAME theory bi-directional COORDINATION network MULTI-AGENT system learning STRATEGY
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Construction and analysis of a plant transformation binary vector pBDGG harboring a bi-directional promoter fusing dual visible reporter genes 被引量:4
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作者 Chunxiao Zhang Ying Gai +3 位作者 Wenqi Wang Yanyan Zhu Xuemei Chen Xiangning Jiang 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2008年第4期245-249,共5页
The constitutive promoter of cauliflower mosaic virus 35S (CaMV 35S) is a polar unidirectional promoter and is widely used in plant genetic engineering. In the present study, the unidirectional CaMV 35S promoter has... The constitutive promoter of cauliflower mosaic virus 35S (CaMV 35S) is a polar unidirectional promoter and is widely used in plant genetic engineering. In the present study, the unidirectional CaMV 35S promoter has been modified to a bi-directional promoter by fusing its minimal promoter element to the 5' end of CaMV 35S promoter in the opposite orientation. To qualitatively and quantitatively estimate its bi-directional transcriptional function and activity, two visible reporter genes, gusA (13-glucuronidase, GUS) and gfp (green fluorescent protein, GFP), were fused to the two ends of the promoter in bi-orientations ending with NOS terminator sequences, respectively. Stable expression of gusA and gfp genes in transgenic tobacco (Nicotiana tabacum L.) was visulized by histochemically staining for GUS and fluorescence microscopic observation under UV for GFP in transgenic plants. The expression of two reporter genes showed that the constructed bi-directional promoter did have the bi-directional transcriptional function in both expected orientations. The quantitative estimation of GUS and GFP were determined on a HITACHI F1000 Fluorescence Spectrophotometer with various wavelengths of excitation and emission. The GUS activity varied from g to 250 pmol 4-MU/min/mg protein and the GFP content varied from 0.9 to 1.8 μg/ mg protein in various lines of transgenic tobacco plants. Higher GUS activity generally coupled with lower GFP content, and vice versa. 展开更多
关键词 bi-directional promoter gusA gene gfp gene Nicotiana tabacum L. expression
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Experimental Investigation of Local Scour Around A New Pile-Group Foundation for Offshore Wind Turbines in Bi-Directional Current 被引量:5
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作者 JI Chao ZHANG Jin-feng +2 位作者 ZHANG Qing-he LI Ming-xing CHEN Tong-qing 《China Ocean Engineering》 SCIE EI CSCD 2018年第6期737-745,共9页
The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity ... The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity and topography of the seabed were measured based on a system composed of plane positioning equipment and an ADV.Experimental results indicate that the development of the scour hole was fast at the beginning, but then the scour rate decreased until reaching equilibrium. Erosion would occur around each pile of the foundation. In most cases, the scour pits were connected in pairs and the outside widths of the scour holes were larger than the inner widths. The maximum scour depth occurred at the side pile of the foundation for each test. In addition, a preliminary investigation shows that the larger the flow velocity, the larger the scour hole dimensions but the shorter equilibrium time. The field maximum scour depth around the foundation was obtained based on the physical experiments with the geometric length scales of 1:27.0, 1:42.5 and 1:68.0, and it agrees with the scour depth estimated by the HEC-18 equation. 展开更多
关键词 offshore wind turbines new pile-group foundation local scour bi-directional current
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Study on Application of Bi-directional Combination Technology Integrating Residue Hydrotreating with Catalytic Cracking RICP 被引量:5
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作者 Niu Chuanfeng Gao Yongcan +1 位作者 Dai Lishun Li Dadong (Research Institute of Petroleum Processing, Beijing 100083) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2008年第1期27-33,共7页
After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catal... After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catalytic cracking called RICP which does not further recycles the FCC heavy cycle oil (HCO) inside the FCC unit and delivers HCO to the residue hydrotreating unit as a diluting oil for the residue that is concurrently subjected to hydrotreating prior to being used as the FCC feed oil. The RICP technology can stimulate residue hydrotreating reactions through utilization of HCO along with an in- creased yield of FCC light distillate, resulting in enhanced petroleum utilization and economic benefits of the refinery. 展开更多
关键词 residue hydrotreating catalytic cracking bi-directional combination heavy cycle oil
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Quantitative measurements of one-dimensional OH absolute concentration profiles in a methane/air flat flame by bi-directional laser-induced fluorescence 被引量:4
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作者 于欣 杨振 +5 位作者 彭江波 张蕾 马欲飞 杨超博 李晓晖 孙锐 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第11期270-279,共10页
The one-dimensional (1D) spatial distributions of OH absolute concentration in methane/air laminar premixed flat flame under different equivalence ratios at atmospheric pressure are investigated by using bi-directio... The one-dimensional (1D) spatial distributions of OH absolute concentration in methane/air laminar premixed flat flame under different equivalence ratios at atmospheric pressure are investigated by using bi-directional laser-induced flu- orescence (LIF) detection scheme combined with the direct absorption spectroscopy. The effective peak absorption cross section and the average temperature at a height of 2 mm above the burner are obtained by exciting absorption on the Q1(8) rotational line in the A2∑+ (Dt = 0) ←- X2∏ (v = 0) at 309.240 nm. The measured values are 1.86×10-15 cm2 and 1719 K, respectively. Spatial filtering and frequency filtering methods of reducing noise are used to deal with the experi- mental data, and the smoothing effects are also compared using the two methods. The spatial distribution regularities of OH concentration are obtained with the equivalence ratios ranging from 0.8 to 1.3. The spatial resolution of the measured result is 84μm. Finally, a comparison is made between the experimental result of this paper and other relevant study results. 展开更多
关键词 bi-directional laser-induced fluorescence laminar premixed flat flame hydroxyl radical absoluteconcentration
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A High-Speed Bi-Directional Visible Light Communication System Based on RGB-LED 被引量:4
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作者 WANG Yuanouan CHI Nan 《China Communications》 SCIE CSCD 2014年第3期40-44,共5页
In this paper, we propose and experimentally demonstrate a bi-directional indoor communication system based on visible light RGB-LED. Spectrally efficient modulation formats (QAM-OFDM), advanced digital signal proce... In this paper, we propose and experimentally demonstrate a bi-directional indoor communication system based on visible light RGB-LED. Spectrally efficient modulation formats (QAM-OFDM), advanced digital signal processing, pre- and post- equalization are adopted to compensate the severe frequency response of indoor channel. In this system, we utilize red-green-blue Light emitting diodes (LEDs), of which each color can be used to carry different signals. For downlink, the low frequencies of each color are used while for uplink, the high frequencies are used. The overall data rate of downlink and uplink are 1.15-Gb/s and 300-Mb/s. The bit error ratios (BERs) for all channels after 0.7 m indoor delivery are below pre-forward- error-correction (pre-FEC) threshold of 3.8×10-3. To the best of our knowledge, this is the highest data rate in bi-directional visible light communication system. 展开更多
关键词 visible light communication bi-directional transmission orthogonal frequencydivision multiplexing light emitting diode
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Application of bi-directional static loading test to deep foundations 被引量:4
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作者 Guoliang Dai Weiming Gong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2012年第3期269-275,共7页
Bi-directional static loading test adopting load cells is widely used around the world at present, with increase in diameter and length of deep foundations. In this paper, a new simple conversion method to predict the... Bi-directional static loading test adopting load cells is widely used around the world at present, with increase in diameter and length of deep foundations. In this paper, a new simple conversion method to predict the equivalent pile head load-settlement curve considering elastic shortening of deep foundation was put forward according to the load transfer mechanism. The proposed conversion method was applied to root caisson foundation in a bridge and to large diameter pipe piles in a sea wind power plant. Some new load cells, test procedure, and construction technology were adopted based on the applications to different deep foundations, which could enlarge the application scopes of bi-directional loading test. A new type of bi-directional loading test for pipe pile was conducted, in which the load cell was installed and loaded after the pipe pile with special connector has been set up. Unlike the conventional bi-directional loading test, the load cell can be reused and shows an evident economic benefit. 展开更多
关键词 deep foundations bi-directional static loading test root caisson foundation large diameter pipe pile
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Bending and free vibrational analysis of bi-directional functionally graded beams with circular cross-section 被引量:2
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作者 Yong HUANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第10期1497-1516,共20页
The bending and free vibrational behaviors of functionally graded(FG)cylindrical beams with radially and axially varying material inhomogeneities are investigated.Based on a high-order cylindrical beam model,where the... The bending and free vibrational behaviors of functionally graded(FG)cylindrical beams with radially and axially varying material inhomogeneities are investigated.Based on a high-order cylindrical beam model,where the shear deformation and rotary inertia are both considered,the two coupled governing differential motion equations for the deflection and rotation are established.The analytical bending solutions for various boundary conditions are derived.In the vibrational analysis of FG cylindrical beams,the two governing equations are firstly changed to a single equation by means of an auxiliary function,and then the vibration mode is expanded into shifted Chebyshev polynomials.Numerical examples are given to investigate the effects of the material gradient indices on the deflections,the stress distributions,and the eigenfrequencies of the cylindrical beams,respectively.By comparing the obtained numerical results with those obtained by the three-dimensional(3D)elasticity theory and the Timoshenko beam theory,the effectiveness of the present approach is verified. 展开更多
关键词 higher-order beam theory circular cross-section bi-directional functionally graded(FG)beam bending analysis free vibration
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Stress Relaxation and Sensitivity Weight for Bi-Directional Evolutionary Structural Optimization to Improve the Computational Efficiency and Stabilization on Stress-Based Topology Optimization 被引量:2
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作者 Chao Ma Yunkai Gao +1 位作者 Yuexing Duan Zhe Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第2期715-738,共24页
Stress-based topology optimization is one of the most concerns of structural optimization and receives much attention in a wide range of engineering designs.To solve the inherent issues of stress-based topology optimi... Stress-based topology optimization is one of the most concerns of structural optimization and receives much attention in a wide range of engineering designs.To solve the inherent issues of stress-based topology optimization,many schemes are added to the conventional bi-directional evolutionary structural optimization(BESO)method in the previous studies.However,these schemes degrade the generality of BESO and increase the computational cost.This study proposes an improved topology optimization method for the continuum structures considering stress minimization in the framework of the conventional BESO method.A global stress measure constructed by p-norm function is treated as the objective function.To stabilize the optimization process,both qp-relaxation and sensitivity weight scheme are introduced.Design variables are updated by the conventional BESO method.Several 2D and 3D examples are used to demonstrate the validity of the proposed method.The results show that the optimization process can be stabilized by qp-relaxation.The value of q and p are crucial to reasonable solutions.The proposed sensitivity weight scheme further stabilizes the optimization process and evenly distributes the stress field.The computational efficiency of the proposed method is higher than the previous methods because it keeps the generality of BESO and does not need additional schemes. 展开更多
关键词 Stress-based topology optimization aggregation function stress relaxation sensitivity weight bi-directional evolutionary structural optimization
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Bi-Directional Giant Magneto Impedance Sensor 被引量:1
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作者 Harsha Uppili Bevin Daglen 《Advances in Materials Physics and Chemistry》 2013年第5期249-254,共6页
A thin film giant magneto impedance (GMI) based on magnetic field sensor has been developed using electrodeposited Ni-Fe permalloy. Chemical composition, surface morphology, and magnetic properties of Ni-Fe permalloy ... A thin film giant magneto impedance (GMI) based on magnetic field sensor has been developed using electrodeposited Ni-Fe permalloy. Chemical composition, surface morphology, and magnetic properties of Ni-Fe permalloy were char-acterized as a function of plateup parameters, and process conditions were established to deposit a Ni-Fe thin film with a high permeability (~1000) and a low coercivity (0.6 Oersted). Conventional GMI sensors are uni-directional and are several millimeters long. In this work, a spiral-shaped sensor using electroplated Ni-Fe permalloy to detect bi-directional magnetic field is reported. Excellent bi-directional magnetic field sensing has been demonstrated using the 1 mm2 compact double-spiral structure. 展开更多
关键词 GIANT MAGNETO IMPEDANCE bi-directional SENSOR PERMALLOY
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