期刊文献+
共找到4,425篇文章
< 1 2 222 >
每页显示 20 50 100
A decision framework for rural domestic sewage treatment models and process:Evidence from Inner Mongolia Autonomous Region,China
1
作者 Ying Yan Pengyu Li +5 位作者 Zixuan Wang Yubo Tan Tianlong Zheng Jianguo Liu Xiaoxia Yang Junxin Liu 《Journal of Environmental Sciences》 2026年第1期302-311,共10页
Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making sys... Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making system to propose a sewage treatment mode and scheme suitable for local conditions.By considering the village spatial layout and terrain factors,a decision tree model of residential density and terrain type was constructed with accuracies of 76.47%and 96.00%,respectively.Combined with binary classification probability unit regression,an appropriate sewage treatment mode for the village was determined with 87.00%accuracy.The Analytic Hierarchy Process(AHP),combined with the Technique for Order Preference(TOPSIS)by Similarity to an Ideal Solution model,formed the basis for optimal treatment process selection under different emission standards.Verification was conducted in 542 villages across three counties of the Inner Mongolia Autonomous Region,focusing on the standard effluent effect(0.3773),low investment cost(0.3196),and high standard effluent effect(0.5115)to determine the best treatment process for the same emission standard under different needs.The annual environmental and carbon emission benefits of sewage treatment in these villages were estimated.This model matches village density,geographic feature,and social development level,and provides scientific support and a theoretical basis for rural sewage treatment decision-making. 展开更多
关键词 Rural domestic sewage Sewage treatment model DECISION-MAKING Environmental-economic benefits Inner Mongolia
原文传递
Prevalence and risk factors of Helicobacter pylori infection in Xinjiang Uygur Autonomous Region:A cross-sectional study of all age groups
2
作者 Qi Jiang Wei-Dong Liu +5 位作者 Wen-Jia Hui Wen-Jie Kong Yan Feng Aihemaijiang Kuerbanjiang Xiao Ling Huang Feng Gao 《World Journal of Gastroenterology》 2025年第21期91-101,共11页
BACKGROUND Helicobacter pylori(H.pylori)infection rates have been changing with different populations and geographic areas.Currently,there is still a lack of comprehensive survey data on the H.pylori infection rate an... BACKGROUND Helicobacter pylori(H.pylori)infection rates have been changing with different populations and geographic areas.Currently,there is still a lack of comprehensive survey data on the H.pylori infection rate and its risk factors in the natural population of Xinjiang Uygur Autonomous Region.AIM To understand the H.pylori infection and risk factors in Xinjiang Uygur Autonomous Region for the prevention and control strategies.METHODS This study comprehensively collected the survey data on H.pylori infection in 15 regions of Xinjiang Uygur Autonomous Region by using the method of stratified random cluster sampling.A total of 4361 individuals from the general population were selected as research subjects,and questionnaire surveys and blood tests for H.pylori antibodies were conducted.RESULTS The overall H.pylori infection rate in Xinjiang Uygur Autonomous Region was 70.79%(3087/4361).The H.pylori infection rate showed a trend of first increasing and then decreasing with the increase of age,and the difference was statistically significant(P<0.05).The analysis of the H.pylori infection rates among different ethnic groups showed that the infection rates of ethnic minorities such as Uyghur,Kirgiz,and Tajik were significantly higher than those of Han and Hui ethnic groups,and the difference was statistically significant(P<0.01).Multivariate analysis showed that altitude,regular consumption of beef,mutton,dried nuts,barbecue foods,and drinking river water were positively correlated with the H.pylori infection rate.CONCLUSION This study indicates that the overall H.pylori infection rate in Xinjiang Uygur Autonomous Region is relatively high,with obvious regional and ethnic differences,which are closely related to the sanitation conditions and eating habits. 展开更多
关键词 Uygur Autonomous Region Helicobacter pylori Infection rate Risk factors Natural population
暂未订购
Introduction to the Bama renowned longevity county in the Guangxi Zhuang Autonomous Region
3
作者 Qi-feng Tang Lu-dan Zhang 《China Geology》 2025年第3期635-638,共4页
Guangxi Zhuang Autonomous Region is one of the most densely clustered regions of“Longevity County”in China,and Bama County is a typical representative of mountainous and hilly longevity villages in the country.In re... Guangxi Zhuang Autonomous Region is one of the most densely clustered regions of“Longevity County”in China,and Bama County is a typical representative of mountainous and hilly longevity villages in the country.In recent years,the local government and residents have actively embraced the United Nations Sustainable Development Goals(SDGs)and the Healthy China Initiative,striving to implement the scientific principle that“lucid waters and lush mountains are invaluable assets.” 展开更多
关键词 United Nations Sustainable Development Goals Bama County Guangxi Zhuang Autonomous Region LONGEVITY sustainable development goals sdgs lucid waters lush mountains Healthy China Initiative
在线阅读 下载PDF
Ecological Adaptability of Different Chinese Liquor-Making Sorghum Varieties in Xiangxi Tujia and Miao Autonomous Prefecture
4
作者 PENG Ming PENG Lin +4 位作者 XIANG Yan LI Xiao-ming WANG Ping-yi SUN Ju LIU Zhao 《Agricultural Science & Technology》 2025年第1期60-64,共5页
Xiangxi Tujia and Miao Autonomous Prefecture of Hunan Province has natural environmental advantages for developing the sorghum industry.To select the high-quality Chinese liquor-making sorghum varieties suitable to be... Xiangxi Tujia and Miao Autonomous Prefecture of Hunan Province has natural environmental advantages for developing the sorghum industry.To select the high-quality Chinese liquor-making sorghum varieties suitable to be planted in Xiangxi,we compared‘Jinnuoliang 1’,‘Chuannuoliang 1’,‘Hongyingzi’,‘Lunuo 8’,‘Chuannuoliang 2’,‘Liangnuo 1’,‘Maohongnuo 1’,and‘Lyubaohong’in terms of growth period,economic traits,incidences of diseases and pests,and lodging rate.The results showed no significant difference in whole growth period among different varieties.‘Liangnuo 1’had the longest growth period of 130 d,while‘Chuannuoliang 1’,‘Hongyingzi’,and‘Maohongnuo 1’had the shortest growth period of 125 d.The yields of different varieties followed the trend of‘Chuannuoliang 2’>‘Lyubaohong’>‘Liangnuo 1’>‘Lunuo 8’>‘Chuannuoliang 1’>‘Maohongnuo 1’>‘Hongyingzi’>‘Jinliangnuo 1’.‘Chuannuoliang 2’had the highest yield,reaching 7128.75 kg/hm^(2).‘Chuannuoliang 1’,‘Chuannuoliang 2’,and‘Lyubaohong’had the lowest incidences of pests and diseases and the lowest lodging rate.Overall analysis suggested that‘Chuannuoliang 2’can be planted and promoted as a Chinese liquormaking sorghum variety in Xiangxi. 展开更多
关键词 Chinese liquor-making sorghum Xiangxi Tujia and Miao Autonomous Prefecture Growth period Economic traits
在线阅读 下载PDF
Spatial Differences in Soil Improvement Effect and Panax ginseng Yield:A Case Study of Yanbian Chaoxianzu(Korean)Autonomous Prefecture
5
作者 Ziqi XIANG Sihai ZHANG +3 位作者 Lin DAI Qiang YE Yujiao ZHANG Yingying WANG 《Agricultural Biotechnology》 2025年第2期38-43,共6页
[Objectives]Farmland ginseng cultivation,as a sustainable alternative to traditional forest-clearing ginseng planting,requires systematic evaluation of soil optimization strategies.This study aimed to quantify the lin... [Objectives]Farmland ginseng cultivation,as a sustainable alternative to traditional forest-clearing ginseng planting,requires systematic evaluation of soil optimization strategies.This study aimed to quantify the linkage between soil improvement outcomes and ginseng(Panax ginseng)yield across five regions in Yanbian Korean Autonomous Prefecture.[Methods]Soil improvement trials were conducted using farmland soils,with forest soils as the baseline.Soil nutrient contents were measured via soil agrochemical analysis method using a continuous flow analyzer.Statistical approaches,including significance tests,correlation analysis,and regression analysis,were applied to identify key factors influencing yield.[Results]Ginseng yield exhibited a significant positive correlation with organic matter content and available phosphorus,but a negative correlation with electrical conductivity,ammonium nitrogen,and available potassium.Wangqing and Liucai regions achieved post-improvement yields equivalent to 94%and 88%of forest soil yields,respectively,demonstrating the highest soil similarity to forest ecosystems.[Conclusions]Region-specific soil improvement protocols in Wangqing and Liucai show high replicability and efficacy.These strategies can serve as benchmarks for sustainable farmland ginseng cultivation,minimizing ecological disruption while maintaining productivity. 展开更多
关键词 Farmland ginseng cultivation Soil improvement Soil nutrients YIELD Correlation analysis
在线阅读 下载PDF
Clinical characteristics of acute adrenal insuffi ciency in emergency patients: an analysis of data in Lhasa, Xizang Autonomous Region of China
6
作者 Guiying Dong Jianbo Yu +6 位作者 Lobsang Chodron Tenzin Chodron Peiliang Gao Xueying Fu Jihong Zhu Zhenzhong Yang Lobsang Cering 《World Journal of Emergency Medicine》 2025年第5期481-485,共5页
BACKGROUND:The nonspecifi c clinical presentation of adrenal insuffi ciency(AI)frequently leads to misdiagnosis,often as psychiatric or gastrointestinal disorders.AI is classifi ed anatomically as primary AI(PAI),seco... BACKGROUND:The nonspecifi c clinical presentation of adrenal insuffi ciency(AI)frequently leads to misdiagnosis,often as psychiatric or gastrointestinal disorders.AI is classifi ed anatomically as primary AI(PAI),secondary AI(SAI),or tertiary AI(TAI).Without timely recognition,progression to adrenal crisis(AC)can result in life-threatening outcomes.This study aimed to systematically analyze the clinical features,etiologies,and outcomes of AI in Lhasa’s emergency population to improve diagnostic accuracy and optimize clinical management.METHODS:A retrospective analysis of emergency department admissions from January 2020 to August 2024 at People’s Hospital of Xizang Autonomous Region was conducted.AI diagnoses were identifi ed via International Classifi cation of Diseases,Tenth Revision,Clinical Modifi cation(ICD-10-CM)codes from electronic health records(EHR).Patients were grouped into incipient AC(IAC)or AC cohorts based on hemodynamic status.Demographic profi les,etiologies,clinical presentations,and laboratory results were analyzed.RESULTS:Forty-three AI patients were identifi ed.The population-standardized admission rate for AI increased from 9 to 16 per million person-years,with PAI cases doubling during this period.Adrenal tuberculosis(58.1%)and adrenal hematoma(18.6%)were the leading etiologies.Compared to the IAC group,the AC group demonstrated lower systolic blood pressure(SBP)(P=0.001)and diastolic blood pressure(DBP)(P<0.001);higher neutrophil count(P=0.048),eosinophil count(P=0.044),CRP(P=0.004),blood urea nitrogen(BUN)(P=0.007);lower sodium(P<0.001)and glucose levels(P=0.001).The hospital stay was longer in the AC group(20 d vs.14 d;P<0.001).CONCLUSION:AI incidence is rising in high-altitude regions,with adrenal tuberculosis remaining the most common cause.AC is associated with increased inflammatory responses,hemodynamic instability,and metabolic disturbances.Targeted interventions are required to improve outcomes. 展开更多
关键词 Adrenal insuffi ciency Adrenal crisis EMERGENCY
暂未订购
Simultaneous Localization and Mapping of Autonomous Underwater Vehicle Using Looking Forward Sonar 被引量:2
7
作者 曾文静 万磊 +1 位作者 张铁栋 黄蜀玲 《Journal of Shanghai Jiaotong university(Science)》 EI 2012年第1期91-97,共7页
A method of underwater simultaneous localization and mapping(SLAM)based on on-board looking forward sonar is proposed.The real-time data flow is obtained to form the underwater acoustic images and these images are pre... A method of underwater simultaneous localization and mapping(SLAM)based on on-board looking forward sonar is proposed.The real-time data flow is obtained to form the underwater acoustic images and these images are pre-processed and positions of objects are extracted for SLAM.Extended Kalman filter(EKF)is selected as the kernel approach to enable the underwater vehicle to construct a feature map,and the EKF can locate the underwater vehicle through the map.In order to improve the association effciency,a novel association method based on ant colony algorithm is introduced.Results obtained on simulation data and real acoustic vision data in tank are displayed and discussed.The proposed method maintains better association effciency and reduces navigation error,and is effective and feasible. 展开更多
关键词 simultaneous localization and mapping(SLAM) autonomous underwater vehicle(AUV) LOOKING FORWARD SONAR extended KALMAN filter(EKF)
原文传递
Adaptive PID control system for an autonomous underwater vehicle 被引量:5
8
作者 王波 Su Yumin Wan Lei Sun Yushan 《High Technology Letters》 EI CAS 2011年第1期7-12,共6页
The control system of an autonomous underwater vehicle (AUV) is introduced. According to control requirements of the AUV, a simple but practical adaptive PID control method is designed The semi-physical simulation ... The control system of an autonomous underwater vehicle (AUV) is introduced. According to control requirements of the AUV, a simple but practical adaptive PID control method is designed The semi-physical simulation is done to test the feasibility of the control system. The neural network idea and the structure of PID controller are referred to design the adaptive PID controller. An intelligent integral is introduced to improve control precision. Compaed with traditional PID con- trollers, the adaptive PID controller has simple structure, good online adjusting ability, fast convergence and good robustness. The simulation experiments also show that the adaptive PID control system has high precision and fine antijamming ability. 展开更多
关键词 autonomous underwater vehicle AUV) control system adaptive PID control semi-physical simulation
在线阅读 下载PDF
Stability Analysis on Speed Control System of Autonomous Underwater Vehicle 被引量:3
9
作者 李晔 庞永杰 +2 位作者 万磊 王芳 廖煜雷 《China Ocean Engineering》 SCIE EI 2009年第2期345-354,共10页
The stability of the motion control system is one of the decisive factors of the control quality for Autonomous Underwater Vehicle(AUV).The divergence of control,which the unstable system may be brought about,is fat... The stability of the motion control system is one of the decisive factors of the control quality for Autonomous Underwater Vehicle(AUV).The divergence of control,which the unstable system may be brought about,is fatal to the operation of AUV.The stability analysis of the PD and S-surface speed controllers based on the Lyapunov's direct method is proposed in this paper.After decoupling the six degree-of-freedom(DOF)motions of the AUV,the axial dynamic behavior is discussed and the condition is deduced,in which the parameters selection within stability domain can guarantee the system asymptotically stable.The experimental results in a tank and on the sea have successfully verified the algorithm reliability,which can be served as a good reference for analyzing other AUV nonlinear control systems. 展开更多
关键词 autonomous underwater vehicle AUV) control system stability analysis Lyapunov's stability theory
在线阅读 下载PDF
New autonomous celestial navigation method for lunar satellite 被引量:6
10
作者 房建成 宁晓琳 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第3期308-310,共3页
Celestial navigation system is an important autonomous navigation system widely used for deep space exploration missions, in which extended Kalman filter and the measurement of angle between celestial bodies are used ... Celestial navigation system is an important autonomous navigation system widely used for deep space exploration missions, in which extended Kalman filter and the measurement of angle between celestial bodies are used to estimate the position and velocity of explorer. In a conventional cartesian coordinate, this navigation system can not be used to achieve accurate determination of position for linearization errors of nonlinear spacecraft motion equation. A new autonomous celestial navigation method has been proposed for lunar satellite using classical orbital parameters. The error of linearizafion is reduced because orbit parameters change much more slowly than the position and velocity used in the cartesian coordinate. Simulations were made with both the cartesiane system and a system based on classical orbital parameters using extended Kalman filter under the same conditions for comparison. The results of comparison demonstrated high precision position determination of lunar satellite using this new method. 展开更多
关键词 deep space exploration lunar satellite autonomous celestial navigation extended Kalman filter
在线阅读 下载PDF
Expert S-surface control for autonomous underwater vehicles 被引量:1
11
作者 张磊 庞永杰 +2 位作者 苏玉民 赵福龙 秦再白 《Journal of Marine Science and Application》 2008年第4期236-242,共7页
S-surface control has proven to be an effective means for motion control of underwater autonomous vehicles(AUV).However there are still problems maintaining steady precision of course due to the constant need to adjus... S-surface control has proven to be an effective means for motion control of underwater autonomous vehicles(AUV).However there are still problems maintaining steady precision of course due to the constant need to adjust parameters,especially where there are disturbing currents.Thus an intelligent integral was introduced to improve precision.An expert S-surface control was developed to tune the parameters on-line,based on the expert system,it provides S-surface control according to practical experience and control knowledge.To prevent control output over-compensation,a fuzzy neural network was included to adjust the production rules to the knowledge base.Experiments were conducted on an AUV simulation platform,and the results show that the expert S-surface controller performs better than an S-surface controller in environments with currents,producing good steady precision of course in a robust way. 展开更多
关键词 autonomous underwater vehicle S-surface control expert control intelligent integral fuzzy neural network
在线阅读 下载PDF
Helicobacter pylori infection in Xinjiang Uyghur Autonomous Region:Prevalence and analysis of related factors 被引量:1
12
作者 Yu-Hua Peng Xue Feng +2 位作者 Zhong Zhou Lei Yang Yun-Fei Shi 《World Journal of Gastroenterology》 SCIE CAS 2023年第43期5834-5847,共14页
BACKGROUND^(14)C urea breath test(^(14)C UBT)and immunohistochemical staining(IHC)are widely used for detection Helicobacter pylori(H.pylori)infection with different sensitivity,and there is a difference in H.pylori i... BACKGROUND^(14)C urea breath test(^(14)C UBT)and immunohistochemical staining(IHC)are widely used for detection Helicobacter pylori(H.pylori)infection with different sensitivity,and there is a difference in H.pylori infection rate in Uyghur and Han ethnic groups.Both need large cohort studies to evaluate the differences more accurately.AIM To analyze the difference between^(14)C UBT and IHC for H.pylori detection in Xinjiang Uyghur Autonomous Region and the difference between Uyghur and Han populations.METHODS There were 3944 cases of H.pylori infection detected by both IHC and^(14)C UBT at the same time(interval<1 wk,with sampling site including gastric antrum,selected from 5747 patients).We compared the sensitivity of^(14)C UBT and IHC.We also compared 555 pairs of Han/Uyghur cases(completely matched for gender and age)for their H.pylori infection rates.The overall H.pylori infection rate of all 5747 cases and the correlation with other clinicopathological data were also further analyzed.SPSS V23.0 software was used for statistical analysis.RESULTS The sensitivity was 94.9%for^(14)C UBT and 65.1%for IHC,which was a significant difference(n=3944,P<0.001).However,among those cases negative for H.pylori by^(14)C UBT(detection value≤100),4.8%were positive by IHC.Combining both methods,the overall H.pylori infection rate was 48.6%(n=5747),and differences in gender,age group,ethnicity and region of residence significantly affected the H.pylori positive rates.According to age group(Han/Uyghur),the positive rates were≤30 years(62.2%/100.0%),31-40 years(45.2%/85.7%),41-50 years(47.2%/79.2%),51-60 years(44.6%/76.1%),61-70 years(40.9%/68.2%),71-80 years(41.7%/54.1%)and≥81 years(42.9%/NA).The H.pylori infection rates of Han/Uyghur paired cases were 41.4%and 73.3%,which was a significant difference(P<0.001)(555 pairs).H.pylori positivity was significantly related to moderate-severe grade 2-3 chronic/active gastritis and intestinal metaplasia(all P<0.05).CONCLUSION The sensitivity of^(14)C UBT was significantly higher,but combined application can still increase the accuracy.The prevention H.pylori should be emphasized for Uygur and young people. 展开更多
关键词 Helicobacter pylori IMMUNOHISTOCHEMISTRY 14C urea breath test HAN UYGHUR Xinjiang Uyghur Autonomous Region
暂未订购
Case Studies on an Approach to Multiple Autonomous Vehicle Motion Coordination 被引量:1
13
作者 G. Paul G. Dissanayake 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S1期26-31,共6页
This paper conducts a series of case studies on a novel Simultaneous Path and Motion Planning (SiPaMoP) approach [1] to multiple autonomous or Automated Guided Vehicle (AGV) motion coordination in bidirectional networ... This paper conducts a series of case studies on a novel Simultaneous Path and Motion Planning (SiPaMoP) approach [1] to multiple autonomous or Automated Guided Vehicle (AGV) motion coordination in bidirectional networks. The SiPaMoP approach plans collision-free paths for vehicles based on the principle of shortest path by dynamically changing the vehicles’ paths,traveling speeds or waiting times,whichever gives the shortest traveling time. It integrates path planning,collision avoidance and motion planning into a comprehensive model and optimizes the vehicles’ path and motion to minimize the completion time of a set of tasks. Five case studies,i.e.,head-on collision avoidance,catching-up collision avoidance,buffer node generation and collision avoidance,prioritybased motion coordination,and safety distance based planning,are presented. The results demonstrated that the method can effectively plan the path and motion for a team of autonomous vehicles or AGVs,and solve the problems of traffic congestion and collision under various conditions. 展开更多
关键词 PATH PLANNING MOTION COORDINATION AUTONOMOUS VEHICLES
在线阅读 下载PDF
Tropical and Subtropical Urban Landscape Plant Cultivation in Southwest China—A Case Study of Honghe Hani and Yi Nationality Autonomous Prefecture 被引量:1
14
作者 LIANG Hui CAO Jihong 《Journal of Landscape Research》 2013年第3期23-28,共6页
By studying current seedling production in Honghe Hani and Yi Nationality Autonomous Prefecture, tropical and subtropical urban landscape plant production in southwest China was analyzed. Local nurseries total 6.40 km... By studying current seedling production in Honghe Hani and Yi Nationality Autonomous Prefecture, tropical and subtropical urban landscape plant production in southwest China was analyzed. Local nurseries total 6.40 km 2 , accounting for 5.1% of total constructed land area in the prefecture, and only 0.02% of the total land area in the prefecture. Application of local plant species in landscape engineering and green coverage ratio lags far behind the indexes of Chinese livable city and indexes of relieving urban heat island effect. By making proper policies and measures, seedling production can be promoted, rare and endanged wild plant species should be fully used to construct garden city, control PM2.5 and protect the living environment. 展开更多
关键词 Honghe Hani and YI NATIONALITY Autonomous Prefecture PM 2.5 Environmental ecology Urban- rural construction GARDEN LANDSCAPING SEEDLING production Research
在线阅读 下载PDF
Geochronology,Geochemistry,and Sr-Nd-Hf Isotopes of the Diorite Porphyrites from the Weining Beishan Area,Ningxia Hui Autonomous Region:Constraints on Their Source and Tectonic Implications 被引量:1
15
作者 Anlu Liu Lianfu Hai +5 位作者 Jinke Liu Xiaojun Zhang Haifeng Li Fengshun Zhao Guoliang Zhao Jinhe Bai 《Journal of Earth Science》 SCIE CAS CSCD 2024年第2期462-475,共14页
The Weining Beishan area of Ningxia Hui Autonomous Region is located at on the western edge of the Helanshan tectonic belt,which is a tectonic joint among Alxa Block,Ordos Block,and North Qilian orogenic belt.However,... The Weining Beishan area of Ningxia Hui Autonomous Region is located at on the western edge of the Helanshan tectonic belt,which is a tectonic joint among Alxa Block,Ordos Block,and North Qilian orogenic belt.However,the tectonic evolution of this area remains unclear due to the lack of magmatic information.This paper conducted researches on geochronology,geochemistry,and Sr-Nd-Hf isotopes of the diorite porphyrites exposed in the Weining Beishan area.The zircon U-Pb dating yields two ages of 145.0±1.1 and 146.2±1.5 Ma,and the whole-rock geochemical data indicate that the diorite porphyrites are metaluminous to weakly peraluminous and high-K calc-alkaline series.The characteristics of highly initial^(87)Sr/^(86)Sr ratios(0.70816 to 0.71047),negativeε_(Nd)(t)(−8.9 to−8.4),and negativeε_(Hf)(t)(−13.8 to−21.2)indicate that the diorite porphyrites originated from partial melting of the middle-lower ancient crust related to the North China Craton.Combined with the regional geology,we suggested that partial melting was triggered by a tectonic activity of deep faults cutting through the crust under the regional stress transformation from compressing to extension during the Late Jurassic–Early Cretaceous,which is probably related to the westward subduction of the Paleo-Pacific Plate. 展开更多
关键词 zircon U-Pb dating Sr-Nd-Hf isotopes magma source diorite porphyrite Weining Beishan area Ningxia Hui Autonomous Region GEOCHRONOLOGY GEOCHEMISTRY
原文传递
Dynamics Modeling and Simulation of Autonomous Underwater Vehicles with Appendages 被引量:3
16
作者 Yumin Su Jinxin Zhao Jian Cao Guocheng Zhang 《Journal of Marine Science and Application》 2013年第1期45-51,共7页
To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster an... To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster and fins with appendages is examined. Based on the dynamic model, a simulation system for the AUV's motion is established. The different kinds of typical motions are simulated to analyze the motion performance and the maneuverability of the AUV. In order to evaluate the influences of appendages on the motion performance of the AUV, simulations of the AUV with and without appendages are performed and compared. The results demonstrate the AUV has good maneuverability with and without appendages. 展开更多
关键词 autonomous underwater vehicle (AUV) motion performance dynamics modeling appendages simulation system
在线阅读 下载PDF
RRT Autonomous Detection Algorithm Based on Multiple Pilot Point Bias Strategy and Karto SLAM Algorithm 被引量:1
17
作者 Lieping Zhang Xiaoxu Shi +3 位作者 Liu Tang Yilin Wang Jiansheng Peng Jianchu Zou 《Computers, Materials & Continua》 SCIE EI 2024年第2期2111-2136,共26页
A Rapid-exploration Random Tree(RRT)autonomous detection algorithm based on the multi-guide-node deflection strategy and Karto Simultaneous Localization and Mapping(SLAM)algorithm was proposed to solve the problems of... A Rapid-exploration Random Tree(RRT)autonomous detection algorithm based on the multi-guide-node deflection strategy and Karto Simultaneous Localization and Mapping(SLAM)algorithm was proposed to solve the problems of low efficiency of detecting frontier boundary points and drift distortion in the process of map building in the traditional RRT algorithm in the autonomous detection strategy of mobile robot.Firstly,an RRT global frontier boundary point detection algorithm based on the multi-guide-node deflection strategy was put forward,which introduces the reference value of guide nodes’deflection probability into the random sampling function so that the global search tree can detect frontier boundary points towards the guide nodes according to random probability.After that,a new autonomous detection algorithm for mobile robots was proposed by combining the graph optimization-based Karto SLAM algorithm with the previously improved RRT algorithm.The algorithm simulation platform based on the Gazebo platform was built.The simulation results show that compared with the traditional RRT algorithm,the proposed RRT autonomous detection algorithm can effectively reduce the time of autonomous detection,plan the length of detection trajectory under the condition of high average detection coverage,and complete the task of autonomous detection mapping more efficiently.Finally,with the help of the ROS-based mobile robot experimental platform,the performance of the proposed algorithm was verified in the real environment of different obstacles.The experimental results show that in the actual environment of simple and complex obstacles,the proposed RRT autonomous detection algorithm was superior to the traditional RRT autonomous detection algorithm in the time of detection,length of detection trajectory,and average coverage,thus improving the efficiency and accuracy of autonomous detection. 展开更多
关键词 Autonomous detection RRT algorithm mobile robot ROS Karto SLAM algorithm
在线阅读 下载PDF
Predefined-Time Backstepping Stabilization of Autonomous Nonlinear Systems 被引量:1
18
作者 Alison Garza-Alonso Michael Basin Pablo Cesar Rodriguez-Ramirez 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第11期2020-2022,共3页
Dear Editor,In this letter,the backstepping technique is applied to solve the predefined-time stabilization problem for autonomous nonlinear systems,where nonlinear terms are unknown but satisfy a linear growth condit... Dear Editor,In this letter,the backstepping technique is applied to solve the predefined-time stabilization problem for autonomous nonlinear systems,where nonlinear terms are unknown but satisfy a linear growth condition.A linear time-varying control law is designed to drive all states of an autonomous nonlinear system to the origin for an a priori preassigned time. 展开更多
关键词 nonlinear AUTONOMOUS satisfy
在线阅读 下载PDF
Autonomous optical navigation for interplanetary exploration based on information of earth-moon 被引量:2
19
作者 吴伟仁 田玉龙 黄翔宇 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第3期343-348,共6页
The image elements of earth-center and moon-center are obtained by processing the images of earthand moon, these image elements in combination with the inertial attitude information and the moon ephemerisare utilized ... The image elements of earth-center and moon-center are obtained by processing the images of earthand moon, these image elements in combination with the inertial attitude information and the moon ephemerisare utilized to obtain the probe initial position relative to earth, and the Levenberg-Marquardt algorithm is usedto determine the accurate probe position relative to earth, and the probe orbit relative to earth is estimated by u-sing the extended Kalman filter. The autonomous optical navigation algorithm is validated using the digital simu-lation. 展开更多
关键词 autonomous optical navigation interplanetary exploration Levenberg-Marquardt algorithm
在线阅读 下载PDF
Autonomous determination of orbit for probe around asteroids using unscented Kalman filter 被引量:1
20
作者 崔平远 崔祜涛 +1 位作者 黄翔宇 栾恩杰 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第3期229-234,共6页
The observed images of the asteroid and the asteroid reference images are used to obtain the probe-to-asteroid direction and the location of the limb features of the asteroid in the inertial coordinate. These informa-... The observed images of the asteroid and the asteroid reference images are used to obtain the probe-to-asteroid direction and the location of the limb features of the asteroid in the inertial coordinate. These informa-tion in combination with the shape model of the asteroid and attitude information of the probe are utilized to ob-tain the position of the probe. The position information is then input to the UKF which determines the real-timeorbit of the probe. Finally, the autonomous orbit determination algorithm is validated using digital simulation.The determination of orbit using UKF is compared with that using extended Kalman filter (EKF), and the resultshows that UKF is superior to EKF. 展开更多
关键词 unscented Kalman filter extended Kalman filter autonomous determination of orbit probe around asteroids
在线阅读 下载PDF
上一页 1 2 222 下一页 到第
使用帮助 返回顶部