检索结果-内蒙古大学图书馆

QPSK/OQPSK signal detection with IFAGC on LEO satellite

QPSK/OQPSK signal detection with IFAGC on LEO satellite

2007 IEEE International Symposium on Microwave, Antenna, Propagation, and EMC Technologies for Wireless Communications, MAPE 2007

作者： Xiaoting, Chen Guodong, zhao Ping, Jin Wenbin, Gong Huijie, Liu xuwen, Liang Shanghai Institute of Micro-System and Information Technology Chinese Academy of Sciences Shanghai 200050 China

ISBN: (纸本)1424410444

The effect of IF (Intermediate Frequency) analog AGC on QPSK/OQPSK signal detection is evaluated for LEO satellite system where Doppler drift, large dynamic range of signal power and low Eb/No condition are difficult to deal with. The way of setting reference value of logarithmic power based AGC is discussed. Coherent accumulation and non-coherent accumulation are used for detecting, while signal's PDF and performance vs. accumulation times are derived mathematically. Experiment shows that with 60KHz Doppler offset, Eb/No=0dB under QPSK/OQPSK, only 16bits was consumed to detect the signal with 99.9% detection probability and 0.1% false alarm probability. ©2007 IEEE.

关键词： Quadrature phase shift keying

来源：评论

学校读者我要写书评

暂无评论

Surface interaction mechanisms of air bubbles, asphaltenes and oil drops in aqueous solutions with implications for interfacial engineering processes

引用

JOURNAL OF COLLOID AND INTERFACE SCIENCE 2023年第1期647卷 264-276页

作者： Yang, Diling zhao, Ziqian Gong, Lu Sun, Yongxiang Peng, xuwen Peng, Qiongyao Wang, Tao Liu, Qi Zhang, Hao Zeng, Hongbo Univ Alberta Dept Chem & Mat Engn Edmonton AB T6G 1H9 Canada

Hypothesis: Surface interactions of bubbles and oil with interface-active species like asphaltenes influence many interfacial phenomena in various engineering processes. It holds both fundamental and practical significance to quantitatively characterize these ***: The surface forces of air bubbles, asphaltenes and asphaltenes-toluene droplets in various aqueous solutions have been quantified using an integrated thin film drainage apparatus and an atomic force microscope coupled with bubble probe. The effects of asphaltenes concentration, pH, salinity, Ca2+ ions and surfactants have been ***: Hydrophobic interaction drives attachment of bubbles and asphaltenes surfaces or oil droplets under high salinity condition. Increasing asphaltenes concentration in oil droplets enhances their hydrophobic attraction with bubbles due to strengthened asphaltenes adsorption and aggregation at oil-water interface. Increasing pH weakens the hydrophobic interaction as oil surfaces become more negatively charged and less hydrophobic. Under low salinity condition, strong electrical double layer and van der Waals repulsion inhibits the bubble-oil droplet contact. Introducing Ca2+ ions and surfactants leads to strong steric repulsion, preventing bubble-oil contact. This research has advanced our mechanistic understanding of how bubbles and oil droplets interact in aqueous systems and offers useful insights to modulate such interactions in oil production, water treatment and other interfacial processes.

关键词： Surface interactions Bubbles Oil droplets Flotation Interfacial Forces Emulsion

来源：评论

学校读者我要写书评

暂无评论

Ecosystem responses to anthropogenic and natural forcing over the last 100 years in the coastal areas of the East China Sea

引用

HOLOCENE 2016年第5期26卷 669-677页

作者： Xing, Lei zhao, Meixun Zhang, Ting Yu, Meng Duan, Shanshan Zhang, Rongping Huh, Chih-An Liao, Wen-Hsuan Feng, xuwen Ocean Univ China Key Lab Marine Chem Theory & Technol Minist Educ Qingdao 266100 Peoples R China Qingdao Collaborat Innovat Ctr Marine Sci & Techn Qingdao Peoples R China Acad Sinica Inst Earth Sci Taipei Taiwan Acad Sinica Res Ctr Environm Changes Taipei Taiwan Acad Sinica Earth Syst Sci Taiwan Int Grad Program Taipei Taiwan State Ocean Adm Inst Oceanog 2 Qingdao Peoples R China

Ecosystem changes of the coastal areas of the East China Sea (ECS) during the past 30 years have been characterized by increased productivity and increased occurrences of dinoflagellate red tides;both were commonly attributed to be caused by anthropogenic input of nutrients. However, climate-driven regime shifts were found in the Pacific, but they have not been observed in the ECS owing to the lack of continuous high resolution data. Hence, it is still a challenge to distinguish the influences of anthropogenic activities and climate changes on ECS shelf ecosystem. We compare phytoplankton biomarker (brassicasterol, dinosterol, and alkenones) data of five box cores from the coastal area of the ECS, which afford phytoplankton productivity and community structure records at decadal-scale resolution for the last 100 years. Phytoplankton productivity in all cores increased during the past 50 years, but community structure changes showed different trends. Relative diatom contribution revealed a decreasing trend during the past ca. 50 years in cores DH5-1 and CJ43 collected near the Changjiang Estuary, which were likely caused by increased N/Si and N/P ratios, providing conditions more favorable for dinoflagellates growth. In contrast, the relative diatom contribution increased in cores 32, 34, and DH6-3 further away and south of the Changjiang Estuary, suggesting limited influence of the Changjiang water. Instead, diatom increasing trend is likely caused by increased supply of phosphorus and silicate, as a result of larger Kuroshio intrusion flux and the corresponding strengthened coastal upwelling. Therefore, both anthropogenic activities and climate-driven coastal upwelling have contributed to increased productivities, but these two forcing mechanisms have resulted in contrasting community structure changes at different sites in the coastal area of the ECS.

关键词： biomarkers Changjiang River coastal upwelling Kuroshio phytoplankton community structure the East China Sea

来源：评论

学校读者我要写书评

暂无评论

GhEXL3 participates in brassinosteroids regulation of fiber elongation in Gossypium hirsutum

引用

PLANT JOURNAL 2024年第2期120卷 491-504页

作者： Zhang, Changsheng Liu, zhao Shu, Sheng Li, Xinyang Li, Yujun Liu, Le Liu, Li Wang, xuwen Li, Fuguang Qanmber, Ghulam Yang, Zuoren Zhengzhou Univ Sch Agr Sci State Key Lab Cotton Biobreeding & Integrated Util Zhengzhou Res Base Zhengzhou Peoples R China Chinese Acad Agr Sci Inst Cotton Res State Key Lab Cotton Biobreeding & Integrated Util Anyang Peoples R China Chinese Acad Agr Sci Western Agr Res Ctr Changji Peoples R China Xinjiang Acad Agr & Reclamat Sci Cotton Res Inst Northwest Inland Reg Key Lab Cotton Biol & Genet B Shihezi Peoples R China

Cotton fiber (Gossypium hirsutum) serves as an ideal model for investigating the molecular mechanisms of plant cell elongation at the single-cell level. Brassinosteroids (BRs) play a crucial role in regulating plant growth and development. However, the mechanism by which BR influences cotton fiber elongation remains incompletely understood. In this study, we identified EXORDIUM-like (GhEXL3) through transcriptome analysis of fibers from BR-deficient cotton mutant pagoda 1 (pag1) and BRI1-EMS-SUPPRESSOR 1 (GhBES1.4, encoding a central transcription factor of BR signaling) overexpression cotton lines. Knockout of GhEXL3 using CRISPR/Cas9 was found to impede cotton fiber elongation, while its overexpression promoted fiber elongation, suggesting a positive regulatory function for GhEXL3 in fiber elongation. Furthermore, in vitro ovule culture experiments revealed that the overexpression of GhEXL3 partially counteracted the inhibitory effects of brassinazole (BRZ) on cotton fiber elongation, providing additional evidence of GhEXL3 involvement in BR signaling pathways. Moreover, our findings demonstrate that GhBES1.4 directly binds to the E-box (CACGTG) motif in the GhEXL3 promoter region and enhances its transcription. RNA-seq analysis revealed that overexpression of GhEXL3 upregulated the expression of EXPs, XTHs, and other genes associated with fiber cell elongation. Overall, our study contributes to understanding the mechanism by which BR regulates the elongation of cotton fibers through the direct modulation of GhEXL3 expression by GhBES1.4.

关键词： cotton fiber brassinosteroids GhEXL3 GhBES1.4 cell elongation

来源：评论

学校读者我要写书评

暂无评论

Optimising maize threshing process with temporal proximity soft actor-critic deep reinforcement learning algorithm

引用

BIOSYSTEMS ENGINEERING 2024年 248卷 229-239页

作者： Zhang, Qiang Fang, xuwen Gao, Xiaodi Zhang, Jinsong zhao, Xuelin Yu, Lulu Yu, Chunsheng Zhou, Deyi Zhou, Haigen Zhang, Li Wu, Xinling Jilin Univ Coll Biol & Agr Engn Changchun 130022 Peoples R China Jilin Jianzhu Univ Sch Emergency Sci & Engn Changchun 130118 Peoples R China

Maize threshing is a crucial process in grain production, and optimising it is essential for reducing post-harvest losses. This study proposes a model-based temporal proximity soft actor-critic (TP-SAC) algorithm to optimise the maize threshing process in the threshing drum. The proposed approach employs an LSTM model as a real-time predictor of threshing quality, achieving an R2 of 97.17% and 98.43% for damage and unthreshed rates on the validation set. In actual threshing experiments, the LSTM model demonstrates an average error of 5.45% and 3.83% for damage and unthreshed rates. The LSTM model is integrated with the TP-SAC algorithm, acting as the environment with which the TP-SAC interacts, enabling efficient training with limited real-world data. The TPSAC algorithm addresses the temporal correlation in the threshing process by incorporating temporal proximity sampling into the SAC algorithm's experience replay mechanism. TP-SAC outperforms the standard SAC algorithm in the simulated environment, demonstrating better sample efficiency and faster convergence. When deployed in actual threshing operations, the TP-SAC algorithm reduces the damage rate by an average of 0.91% across different feed rates compared to constant control. The proposed TP-SAC algorithm offers a novel and practical approach to optimising the maize threshing process, enhancing threshing quality.

关键词： Threshing quality optimisation Agricultural machinery Machine learning Agricultural automation Sensitivity analysis

来源：评论

学校读者我要写书评

暂无评论

Stereo Matching Algorithm of Color Image Based on Weber's Law and Census

Stereo Matching Algorithm of Color Image Based on Weber's La...

引用

International Conference on Intelligent Information Hiding and Multimedia Signal Processing (IIHMSP)

作者： Qiang Wu Xiangnan zhao xuwen Li College of Electronic Information and Control Engineering Beijing University of Technology Beijing China College of Life Science and Bioengineering Beijing University of Technology Beijing China

The algorithm presented here is used on unmanned aerial vehicles system. In 2013,*** proposed a matching cost computation model(or function), This matching cost model combined three kinds of constraints, the cost function is formulated by combining three individual costs:a cost computed on an extended census transformation of the images, the absolute difference cost, taking into account information from colour channels, and a cost based on the principal image *** show that the cost function is excellent performance in similar *** it to the stereo matching of ancient buildings, it is favorable for practical. However, this experiment, in color mutated region, leaded to blurred ***, our proposed method added color space structural information, which based on HVS Weber's law, to the cost function. we use the differential excitation of WLD reflects the structure of color *** robust cost measures can reduce percent of bad pixels in mutated color region. The proposed method use color image, which is used after epipolar line rectification.

关键词： Image color analysis Cost function Transforms Robustness Computed tomography Stereo vision Skeleton

来源：评论

学校读者我要写书评

暂无评论

Altered levels of circulating CD8⁺CXCR5⁺PD-1⁺T follicular cytotoxic cells in primary Sjogren's syndrome

引用

CLINICAL RHEUMATOLOGY 2022年第6期41卷 1697-1708页

作者： Zhai, xuwen Wang, Yanlin Guo, Hui Liang, zhaojun Feng, Min Wu, Yanyao Qin, Yan zhao, Xiangcong Gao, Chong Luo, Jing Shanxi Med Univ Simulat Hosp Clin Skills Teaching Jinzhong 030600 Shanxi Peoples R China Shanxi Med Univ Dept Med Div Rheumatol Hosp 2 Taiyuan 030001 Shanxi Peoples R China Shanxi Med Univ Dept Med Div Nephrol Hosp 2 Taiyuan 030001 Shanxi Peoples R China Shenzhen Baoan Shiyan Peoples Hosp Dept Med Div Nephrol Shenzhen 518005 Guangdong Peoples R China Harvard Med Sch Brigham & Womens Hosp Dept Pathol Boston MA 02115 USA

Background Circulating CD8(+)T-cells expressing the C-X-C chemokine receptor type 5 (CXCR5) (CD8(+)CXCR5(+)T), a recently identified follicular cytotoxic T cell subset, are involved in antiviral immunity and autoimmunity, but their abundance and role in the pathogenesis of primary Sjogren syndrome (pSS) are unknown. Methods Circulating CD8(+)CXCR5(+)T cell and CD8(+) regulatory T cells (CD8(+)Treg) were evaluated in 49 pSS patients (19 patients with pulmonary involvement) and 24 age- and sex-matched healthy controls (HCs) by flow cytometry. Orthogonal partial least squares discriminant analysis (OPLS-DA) was performed, and receiver operating characteristic curves (ROC) were generated to identify characteristic cell subsets. Spearman's correlation analysis was conducted to examine the relationships between CD8(+)T cell subsets and clinical features. Results The proportions and numbers of CD8(+)CXCR5(+) , CD8(+)CXCR5(+) programmed death 1-positive (PD-1(+)), and CD8(+)CXCR5 PD-1(+)T cells were significantly higher, whereas those of CD8 +/- Treg were markedly lower, in pSS patients than HCs. The CD8(+)CXCR5(+)PD-1(+)T cell to CD8(+)Treg ratio had the greatest discriminatory power for pSS and HCs according to OPLS-DA and ROC analyses. The increased numbers of CD8(+)CXCR5(+)T cells and CD8(+)CXCR5(+)PD-1(+)T cells were strongly associated with those of CD4(+)CXCR5(+)T and B cells. The proportions and numbers of CD8(+)CXCR5(+)PD-1(+)T cells were increased in pSS patients with lung involvement. Conclusions We identified a new CD8(+)CXCR5(+)PD-1(+)T subset, which was increased in abundance in pSS patients, particularly those with lung involvement, compared with HCs. Also, the CD8(+)CXCR5(+)PD-1(+)T to CD8(+)Treg ratio may be useful for identifying pSS. Our findings suggest that targeting follicular CD8(+)T cell subsets has therapeutic potential for pSS.

关键词： CD8(+)CXCR5(+) follicular cytotoxic T subsets CD8(+) regulatory T cells Lung involvement OPLS-DA Primary Sjogren's syndrome

来源：评论

学校读者我要写书评

暂无评论

Characterization of thermal neutron distribution of an Am-Be neutron source setup by CdZnTe detector

引用

APPLIED RADIATION AND ISOTOPES 2023年 196卷 110778页

作者： Liang, xuwen zhao, Dong Jia, Wenbao Hei, Daqian Cheng, Can Nanjing Univ Aeronaut & Astronaut Dept Nucl Sci & Technol Nanjing Peoples R China Jiangsu Higher Educ Inst Collaborat Innovat Ctr Radiat Med Suzhou 215000 Peoples R China Lanzhou Univ Sch Nucl Sci & Technol Lanzhou 730000 Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Astronaut Nanjing 211106 Peoples R China

Owing to the developments in prompt gamma neutron activation analysis (PGNAA) and prompt gamma ray activation imaging (PGAI), it is necessary to develop an online thermal neutron distribution measurement method. The CdZnTe detector is considered as an alternative thermal neutron detector because of its high thermal neutron capture cross section. In this study, the thermal neutron field of an 241Am-Be neutron source was determined by CdZnTe detector. The intrinsic neutron detection efficiency of CdZnTe detector was calcu-lated by using indium foil activation, and the value was 3.65%. Then the characteristics of neutron source were conducted with the calibrated CdZnTe detector. The thermal neutron fluxes in front of beam port were measured at several distances ranging from 0 cm up to 28 cm. Thermal neutron field at distances of 1 cm and 5 cm were also measured. The experimental data were then compared with Monte Carlo simulation. The results demon-strated that the simulated data agree well with experimental measurements.

关键词： CdZnTe detector Monte Carlo simulation Am -Be neutron source Activation method Thermal neutron flux

来源：评论

学校读者我要写书评

暂无评论

Gut microbiota analysis of juvenile genetically improved farmed tilapia (Oreochromis niloticus) by dietary supplementation of different resveratrol concentrations

引用

FISH & SHELLFISH IMMUNOLOGY 2018年 77卷 200-207页

作者： Zheng, Yao Wu, Wei Hu, Gengdong Qiu, Liping Meng, Shunlong Song, Chao Fan, Limin zhao, Zhixiang Bing, xuwen Chen, Jiazhang Chinese Acad Fishery Sci Freshwater Fisheries Res Ctr 9 Shanshui East Rd Wuxi 214081 Jiangsu Peoples R China Minist Agr Fishery Ecoevironm Monitoring Ctr Lower Reaches Y Wuxi 214081 Jiangsu Peoples R China Minist Agr Lab Qual & Safety Risk Assessment Aquat Prod Envi Wuxi 214081 Jiangsu Peoples R China Nanjing Agr Univ Wuxi Fishery Coll Wuxi 214081 Jiangsu Peoples R China Minist Agr Key Lab Control Qual & Safety Aquat Prod Wuxi Jiangsu Peoples R China

The genetically improved farmed tilapia (GIFT, Oreochromis niloticus) is cultured widely for production of freshwater fish in China, while streptococcosis, likely related to pathogenic infections, occurs frequently in juvenile, mother, and operated GIFT. The gut microbiota plays an important role in nutrient digestibility in animals, and resveratrol (RES) has been used in feed for different freshwater fish species. Therefore, understanding changes in the tilapia gut microbiota across different concentrations of dietary RES supplementation is extremely important. The gut microbiota population in tilapia at 45 d after supplementation with different concentrations (0, 0.025, 0.05, 0.1 g/kg) of dietary RES was assessed by 16S rDNA gene sequencing. A total of 5445 operational taxonomic units were identified from all samples, and 14 phyla and 81 families were identified from all fecal samples. The bacteria of the phylum Firmicutes were significantly enriched in the 0.025 g/kg RES group when compared with the controls. Proteobacteria, Firmicutes and Cyanobacteria were the most dominant three phyla in all samples. With the increasing concentrations, the proportion of beneficial microbial taxa (Acetobacteraceae and Methylobacteriaceae) increased, whereas the proportion of harmful microbial taxa decreased, eg. Streptococcaceae except for 0.1 g/kg RES groups. RES did not affect the richness and diversity in tilapia gut microbiota. These findings provide information on the diversity and differences in GIFT gut microbiota database, and may contribute to developing strategies for management of diseases and long-term sustainability of O. niloticus culture.

关键词： Resveratrol GIFT Gut microbiota 16S rDNA Disease defense

来源：评论

学校读者我要写书评

暂无评论

Analysis and Validation of a Unified Slip Factor Model for Impellers at Design and Off-Design Conditions

引用

JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME 2011年第4期133卷 41018-41018页

作者： Qiu, xuwen Japikse, David zhao, Jinhui Anderson, Mark R. Concepts NREC White River Jct VT 05001 USA

This paper presents a unified slip model for axial, radial, and mixed-flow impellers. The core assumption of the model is that the flow deviation or the slip velocity at the impeller exit is mainly originated from the blade loading near the discharge of an impeller and its subsequent relative eddy in the impeller passage. The blade loading is estimated and then used to derive the slip velocity using Stodola's assumption. The final form of the slip factor model can be successfully related to Carter's rule for axial impellers and Stodola's slip model for radial impellers, making the case for this model applicable to axial, radial, and mixed-flow impellers. Unlike conventional slip factor models for radial impellers, the new slip model suggests that the flow coefficient at the impeller exit is an important variable for the slip factor when there is significant blade turning at the impeller discharge. This explains the interesting off-design trends for slip factor observed from experiments, such as the rise of the slip factor with flow coefficient in the Eckardt A impeller. Extensive validation results for this new model are presented in this paper. Several cases are studied in detail to demonstrate how this new model can capture the slip factor variation at the off-design conditions. Furthermore, a large number of test data from more than 90 different compressors, pumps, and blowers were collected. Most cases are radial impellers, but a few axial impellers are also included. The test data and model predictions of the slip factor are compared at both design and off-design flow conditions. In total, over 1650 different flow conditions are evaluated. The unified model shows a clear advantage over the traditional slip factor correlations, such as the Busemann-Wiesner model, when off-design conditions are considered. [DOI: 10.1115/1.4003022]

关键词： blades design impellers

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：