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Misdiagnosis of food-borne foreign bodies outside of the digestive tract on magnetic resonance imaging:Two case reports
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作者 Dan Ji Jian-Dong Lu +1 位作者 Zhi-Guo Zhang Xu-Ping Mao 《World Journal of Clinical Cases》 SCIE 2023年第7期1650-1655,共6页
BACKGROUND Patients with foreign bodies in the digestive tract are often encountered,but complete penetration of a foreign body through the gastrointestinal tract is rare,and the choice of imaging method is very impor... BACKGROUND Patients with foreign bodies in the digestive tract are often encountered,but complete penetration of a foreign body through the gastrointestinal tract is rare,and the choice of imaging method is very important.Improper selection may lead to missed diagnosis or misdiagnosis.CASE SUMMARY An 81-year-old man was diagnosed as having a liver malignancy after he took magnetic resonance imaging and positron emission tomography/computed tomography(CT)examinations.The pain improved after the patient accepted gamma knife treatment.However,he was admitted to our hospital 2 mo later due to fever and abdominal pain.This time,he received a contrast-enhanced CT scan,which showed fish-boon-like foreign bodies in the liver with peripheral abscess formation,then he went to the superior hospital for surgery.It lasted for more than 2 mo from the onset of the disease to the surgical treatment.A 43-year-old woman with a 1 mo history of a perianal mass with no obvious pain or discomfort was diagnosed as having an anal fistula with the formation of a local small abscess cavity.Clinical perianal abscess surgery was performed,and fish bone foreign body was found in perianal soft tissue during the operation.CONCLUSION For patients with pain symptoms,the possibility of foreign body perforation should be considered.Magnetic resonance imaging is not comprehensive and that a plain computed tomography scan of the pain area is necessary. 展开更多
关键词 Acute abdomen Bowel perforation Liver foreign body Buttocks foreign body Fish bone Case report
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Vibrational Suspension of Two Cylinders in a Rotating Liquid-Filled Cavity with a Time-Varying Rotation Rate
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作者 Olga Vlasova 《Fluid Dynamics & Materials Processing》 EI 2024年第9期2127-2137,共11页
The dynamics of rotating hydrodynamic systems containing phase inclusions are interesting due to the related widespread occurrence in nature and technology.The influence of external force fields on rotating systems ca... The dynamics of rotating hydrodynamic systems containing phase inclusions are interesting due to the related widespread occurrence in nature and technology.The influence of external force fields on rotating systems can be used to control the dynamics of inclusions of various types.Controlling inclusions is of current interest for space technologies.In low gravity,even a slight vibration effect can lead to the appearance of a force acting on phase inclusions near a solid boundary.When vibrations are applied to multiphase hydrodynamic systems,the oscillating body intensively interacts with the fluid and introduces changes in the related flow structure.Asymmetries in the fluid flow lead to the appearance of an averaged force.As a result,the body is repelled from the cavity boundary and takes a position at a certain distance from it.The vibrationally-induced movement of phase inclusions in liquids can be used to improve various technological processes(for example,when degassing and cleaning liquids from solid inclusions,mixing various components,etc.).This study presents a relevant methodology to study the averaged vibrational force acting on a pair of free cylindrical bodies near the oscillating wall of a cavity.Attention is paid to the region of moderate and low dimensionless frequencies when the size of the inclusion is consistent with the thickness of the Stokes boundary layer.The dynamics of these bodies is considered in a horizontal cylindrical cavity with a fluid undergoing modulated rotation.The average lift force of a vibrational nature is measured by the method of quasi-stationary suspension of bodies whose density differs from the density of the liquid in a static centrifugal force field.The developed technique makes it possible to determine the dependence of the lift force on vibration parameters and the distance from the oscillating boundary at which solid inclusions are located.It is shown that in the region of moderate dimensionless frequencies,the average lift force acting on an inclusion near the boundary undergoing modulated rotation almost linearly depends on the dimensionless frequency. 展开更多
关键词 Solid bodies rotational oscillations viscous fluid lift force
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Uninvolved liver dose prediction in stereotactic body radiation therapy for liver cancer based on the neural network method
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作者 Huai-Wen Zhang You-Hua Wang +1 位作者 Bo Hu Hao-Wen Pang 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第10期4146-4156,共11页
BACKGROUND The quality of a radiotherapy plan often depends on the knowledge and expertise of the plan designers.AIM To predict the uninvolved liver dose in stereotactic body radiotherapy(SBRT)for liver cancer using a... BACKGROUND The quality of a radiotherapy plan often depends on the knowledge and expertise of the plan designers.AIM To predict the uninvolved liver dose in stereotactic body radiotherapy(SBRT)for liver cancer using a neural network-based method.METHODS A total of 114 SBRT plans for liver cancer were used to test the neural network method.Sub-organs of the uninvolved liver were automatically generated.Correlations between the volume of each sub-organ,uninvolved liver dose,and neural network prediction model were established using MATLAB.Of the cases,70%were selected as the training set,15%as the validation set,and 15%as the test set.The regression R-value and mean square error(MSE)were used to evaluate the model.RESULTS The volume of the uninvolved liver was related to the volume of the corresponding sub-organs.For all sets of Rvalues of the prediction model,except for D_(n0)which was 0.7513,all R-values of D_(n10)-D_(n100)and D_(nmean)were>0.8.The MSE of the prediction model was also low.CONCLUSION We developed a neural network-based method to predict the uninvolved liver dose in SBRT for liver cancer.It is simple and easy to use and warrants further promotion and application. 展开更多
关键词 Dose prediction Sub-organ Machine learning Stereotactic body radiotherapy Liver cancer
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Priority Based Energy Efficient MAC Protocol by Varying Data Ratefor Wireless Body Area Network
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作者 R.Sangeetha Usha Devi Gandhi 《Computer Systems Science & Engineering》 2024年第2期395-411,共17页
Wireless Body Area Network(WBAN)is a cutting-edge technology that is being used in healthcare applications to monitor critical events in the human body.WBAN is a collection of in-body and on-body sensors that monitor ... Wireless Body Area Network(WBAN)is a cutting-edge technology that is being used in healthcare applications to monitor critical events in the human body.WBAN is a collection of in-body and on-body sensors that monitor human physical parameters such as temperature,blood pressure,pulse rate,oxygen level,body motion,and so on.They sense the data and communicate it to the Body Area Network(BAN)Coordinator.The main challenge for the WBAN is energy consumption.These issues can be addressed by implementing an effective Medium Access Control(MAC)protocol that reduces energy consumption and increases network lifetime.The purpose of the study is to minimize the energy consumption and minimize the delay using IEEE 802.15.4 standard.In our proposed work,if any critical events have occurred the proposed work is to classify and prioritize the data.We gave priority to the highly critical data to get the Guarantee Tine Slots(GTS)in IEEE 802.15.4 standard superframe to achieve greater energy efficiency.The proposed MAC provides higher data rates for critical data based on the history and current condition and also provides the best reliable service to high critical data and critical data by predicting node similarity.As an outcome,we proposed a MAC protocol for Variable Data Rates(MVDR).When compared to existing MAC protocols,the MVDR performed very well with low energy intake,less interruption,and an enhanced packet-sharing ratio. 展开更多
关键词 Wireless Body Area Network(WBAN) IEEE 802.15.4 energy efficiency MAC protocol ZIGBEE
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Management of Vulnating Esophageal Foreign Bodies in Burkina Faso
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作者 Ibrahima Diallo Aboubacar Gouéta +8 位作者 Alseny Camara Assoumi Anatou Biga Mama Brigitte Ouoba Edi Emmanuel Martial Nao Moustapha Sérémé Bertin Priva Ouédraogo Yvette Marie Chantal Gyébré Abdoulaye Keita Alpha Oumar Diallo 《International Journal of Otolaryngology and Head & Neck Surgery》 2024年第2期135-148,共14页
Introduction: Esophageal foreign bodies (EFB) are a diagnostic and therapeutic emergency because of the serious complications they can cause. Aim: This paper aimed to study the vulnating esophageal foreign bodies in t... Introduction: Esophageal foreign bodies (EFB) are a diagnostic and therapeutic emergency because of the serious complications they can cause. Aim: This paper aimed to study the vulnating esophageal foreign bodies in the ENT and Head and Neck Surgery departments of the Yalgado Ouedraogo and Bogodogo University Hospital. Methodology: This was an analytic cross-sectional study with retrospective data collection over 10 years (2012-2021). Results: We collected 91 cases of vulnating esophageal foreign bodies, i.e. 9.1 cases/year (4.7%). The mean age of the patients was 14 ± 19 years. The sex ratio was 1.6. The circumstances of occurrence were dominated by accidental ingestion of vulnating esophageal foreign bodies (98.9%). The average time to consultation was 7.5 hours. Dysphagia was the dominant symptom (64.8%). Cervico-thoracic radiography found dual contour radiopaque images in 71.4%. Esophagoscopy with rigid tube was performed in 97.8%. The average time for extraction of the vulnating esophageal foreign bodies was 8 hours. Vulnerating esophageal foreign bodies were non-organic in 84.6%. The button cell represented 64.8%. Their location was cervical in 61.5% intraoperatively. The lesion assessment found ulcerative lesions in 42.9% (p Conclusion: Vulnating esophageal foreign bodies are relatively frequent in our ENT practice. Although their diagnosis is often easy, their treatment is still difficult and requires multidisciplinary management. Thus, for us, prevention remains the first effective weapon. 展开更多
关键词 Foreign bodies ESOPHAGUS VULNERABLE MANAGEMENT SEQUELAE
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DNBP-CCA:A Novel Approach to Enhancing Heterogeneous Data Traffic and Reliable Data Transmission for Body Area Network
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作者 Abdulwadood Alawadhi Mohd.Hasbullah Omar +3 位作者 Abdullah Almogahed Noradila Nordin Salman A.Alqahtani Atif M.Alamri 《Computers, Materials & Continua》 SCIE EI 2024年第5期2851-2878,共28页
The increased adoption of Internet of Medical Things (IoMT) technologies has resulted in the widespread use ofBody Area Networks (BANs) in medical and non-medical domains. However, the performance of IEEE 802.15.4-bas... The increased adoption of Internet of Medical Things (IoMT) technologies has resulted in the widespread use ofBody Area Networks (BANs) in medical and non-medical domains. However, the performance of IEEE 802.15.4-based BANs is impacted by challenges related to heterogeneous data traffic requirements among nodes, includingcontention during finite backoff periods, association delays, and traffic channel access through clear channelassessment (CCA) algorithms. These challenges lead to increased packet collisions, queuing delays, retransmissions,and the neglect of critical traffic, thereby hindering performance indicators such as throughput, packet deliveryratio, packet drop rate, and packet delay. Therefore, we propose Dynamic Next Backoff Period and Clear ChannelAssessment (DNBP-CCA) schemes to address these issues. The DNBP-CCA schemes leverage a combination ofthe Dynamic Next Backoff Period (DNBP) scheme and the Dynamic Next Clear Channel Assessment (DNCCA)scheme. The DNBP scheme employs a fuzzy Takagi, Sugeno, and Kang (TSK) model’s inference system toquantitatively analyze backoff exponent, channel clearance, collision ratio, and data rate as input parameters. Onthe other hand, the DNCCA scheme dynamically adapts the CCA process based on requested data transmission tothe coordinator, considering input parameters such as buffer status ratio and acknowledgement ratio. As a result,simulations demonstrate that our proposed schemes are better than some existing representative approaches andenhance data transmission, reduce node collisions, improve average throughput, and packet delivery ratio, anddecrease average packet drop rate and packet delay. 展开更多
关键词 Internet of Medical Things body area networks backoff period tsk fuzzy model clear channel assessment media access control
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Quantitative Evaluation of Heavy Metal Pollution and Its Influencing Factors in Water Bodies of Karst Areas
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作者 Dijin MU Shizhen XIAO 《Meteorological and Environmental Research》 2024年第1期75-82,共8页
At present, there is relatively little research on the synergistic effects of heavy metals in soil, sediment, and bedrock on heavy metal pollution in water bodies. In this paper, heavy metals in soil, sediment, bedroc... At present, there is relatively little research on the synergistic effects of heavy metals in soil, sediment, and bedrock on heavy metal pollution in water bodies. In this paper, heavy metals in soil, sediment, bedrock, and water of a typical karst watershed in southwest China were investigated. The results indicated that the average values of heavy metals in soil and sediment were relatively higher than those in bedrock except for Ni and As. During the research period, As and Cd were the main heavy metal elements polluting the soil and sediment in the study area, while water bodies were mainly polluted by Ni, As, and Cd. The pollution assessment indicated that there were instances of poor or very poor water quality in the study area during the study period;the soil as a whole was slightly polluted by Cd and As;sediment was subject to moderate Cd pollution and mild As pollution. Analysis of geochemical form for heavy metals showed that heavy metals in soil and sediment were mainly in residual form, and the proportions of exchangeable As and Cd were relatively high. Multiple statistical analysis showed that heavy metals in sediment, soil, and bedrock explained 23.8%, 16.8%, and 16.2% of the changes in heavy metals of water, respectively. The research results can provide scientific basis for the prevention and control of heavy metal pollution in water bodies. 展开更多
关键词 Water body SEDIMENT Soil BEDROCK Speciation forms POLLUTION Influence factor
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Unraveling the efficacy network: A network meta-analysis of adjuvant external beam radiation therapy methods after hepatectomy
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作者 Gao-Yuan Yang Zhi-Wei He +7 位作者 Yong-Chang Tang Feng Yuan Ming-Bo Cao Yu-Peng Ren Yu-Xuan Li Xiao-Rui Su Zhi-Cheng Yao Mei-Hai Deng 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第1期205-214,共10页
BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent ... BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent recurrence after liver cancer resection.However,there are multiple RT techniques available,and the differ-ential effects of these techniques in preventing postoperative liver cancer re-currence require further investigation.AIM To assess the advantages and disadvantages of various adjuvant external RT methods after liver resection based on overall survival(OS)and disease-free survival(DFS)and to determine the optimal strategy.METHODS This study involved network meta-analyses and followed the PRISMA guidelines.The data of qualified studies published before July 10,2023,were collected from PubMed,Embase,the Web of Science,and the Cochrane Library.We included relevant studies on postoperative external beam RT after liver resection that had OS and DFS as the primary endpoints.The magnitudes of the effects were determined using risk ratios with 95%confidential intervals.The results were analyzed using R software and STATA software.RESULTS A total of 12 studies,including 1265 patients with hepatocellular carcinoma(HCC)after liver resection,were included in this study.There was no significant heterogeneity in the direct paired comparisons,and there were no significant differences in the inclusion or exclusion criteria,intervention measures,or outcome indicators,meeting the assumptions of heterogeneity and transitivity.OS analysis revealed that patients who underwent stereotactic body radiotherapy(SBRT)after resection had longer OS than those who underwent intensity modulated radiotherapy(IMRT)or 3-dimensional conformal RT(3D-CRT).DFS analysis revealed that patients who underwent 3D-CRT after resection had the longest DFS.Patients who underwent IMRT after resection had longer OS than those who underwent 3D-CRT and longer DFS than those who underwent SBRT.CONCLUSION HCC patients who undergo liver cancer resection must consider distinct advantages and disadvantages when choosing between SBRT and 3D-CRT.IMRT,a RT technique that is associated with longer OS than 3D-CRT and longer DFS than SBRT,may be a preferred option. 展开更多
关键词 Primary liver cancer Hepatocellular carcinoma Network meta-analysis External beam radiation therapy Stereotactic body radiotherapy Intensity modulated radiotherapy
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Oxygen and hydrogen isotope characteristics of different water bodies in the Burqin River Basin of the Altay Mountains,China
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作者 XIE Yida WANG Feiteng LIU Shuangshuang 《Journal of Arid Land》 SCIE CSCD 2024年第10期1365-1379,共15页
Characterization of the spatial and temporal variability of stable isotopes in surface water is essential for interpreting hydrological processes.In this study,we collected the water samples of river water,groundwater... Characterization of the spatial and temporal variability of stable isotopes in surface water is essential for interpreting hydrological processes.In this study,we collected the water samples of river water,groundwater,and reservoir water in the Burqin River Basin of the Altay Mountains,China in 2021,and characterized the oxygen and hydrogen isotope variations in different water bodies via instrumental analytics and modeling.Results showed significant seasonal variations in stable isotope ratios of oxygen and hydrogen(δ18O andδ2H,respectively)and significant differences inδ18O andδ2H among different water bodies.Higherδ18O andδ2H values were mainly found in river water,while groundwater and reservoir water had lower isotope ratios.River water and groundwater showed differentδ18O-δ2H relationships with the local meteoric water line,implying that river water and groundwater are controlled by evaporative enrichment and multi-source recharge processes.The evaporative enrichment experienced by reservoir water was less significant and largely influenced by topography,recharge sources,local moisture cycling,and anthropogenic factors.Higher deuterium excess(d-excess)value of 14.34‰for river water probably represented the isotopic signature of combined contributions from direct precipitation,snow and glacial meltwater,and groundwater recharge.The average annual d-excess values of groundwater(10.60‰)and reservoir water(11.49‰)were similar to the value of global precipitation(10.00‰).The findings contribute to understanding the hydroclimatic information reflected in the month-by-month variations in stable isotopes in different water bodies and provide a reference for the study of hydrological processes and climate change in the Altay Mountains,China. 展开更多
关键词 water bodies stable isotopes deuterium excess(d-excess) Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model Burqin River Basin Altay Mountains
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The Criteria for Reducing Centrally Restricted Three-Body Problem to Two-Body Problem
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作者 Bijay Kumar Sharma 《International Journal of Astronomy and Astrophysics》 2024年第1期1-19,共19页
Our Solar System contains eight planets and their respective natural satellites excepting the inner two planets Mercury and Venus. A satellite hosted by a given Planet is well protected by the gravitational pertubatio... Our Solar System contains eight planets and their respective natural satellites excepting the inner two planets Mercury and Venus. A satellite hosted by a given Planet is well protected by the gravitational pertubation of much heavier planets such as Jupiter and Saturn if the natural satellite lies deep inside the respective host Planet Hill sphere. Each planet has a Hill radius a<sub>H</sub> and planet mean radius R<sub>P </sub>and the ratio R<sub>1</sub>=R<sub>P</sub>/a<sub>H</sub>. Under very low R<sub>1 </sub>(less than 0.006) the approximation of CRTBP (centrally restricted three-body problem) to two-body problem is valid and planet has spacious Hill lobe to capture a satellite and retain it. This ensures a high probability of capture of natural satellite by the given planet and Sun’s perturbation on Planet-Satellite binary can be neglected. This is the case with Earth, Mars, Jupiter, Saturn, Neptune and Uranus. But Mercury and Venus has R<sub>1</sub>=R<sub>P</sub>/a<sub>H</sub> =0.01 and 5.9862 × 10<sup>-3</sup> respectively hence they have no satellites. There is a limit to the dimension of the captured body. It must be a much smaller body both dimensionally as well masswise. The qantitative limit is a subject of an independent study. 展开更多
关键词 Hill’s Radius two-Body Problem Fixed-Point Solution Lagrange Points Earth-Moon-Test Particle CRTBP
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Psammoma Bodies in Two Types of Human Ovarian Tumours: A Mineralogical Study 被引量:1
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作者 MENG Fanlu WANG Changqiu +3 位作者 LI Yan LU Anhuai MEI Fang LIU Jianying 《矿物学报》 CAS CSCD 北大核心 2013年第S1期67-67,共1页
Mineralization in tumours is a complex dynamic process regulated by cancerization process, organic matter, mineral crystal growth mechanism, external environment, human body environment and other aspects. Differences ... Mineralization in tumours is a complex dynamic process regulated by cancerization process, organic matter, mineral crystal growth mechanism, external environment, human body environment and other aspects. Differences between mineral crystals may imply different cancerization process and tumorous types. Therefore, the study on mineralization progress in human tumours can help to provide some important information on the occurrence and development of the diseases. 展开更多
关键词 MINERALOGY SYNCHROTRON radiation OVARIAN SEROUS cancer teratomas psammoma bodies
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Brunn-Minkowski inequalities for star duals of intersection bodies and two additions 被引量:1
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作者 刘丽娟 汪卫 何斌吾 《Journal of Shanghai University(English Edition)》 CAS 2010年第3期201-205,共5页
In this paper,we first establish the dual Brunn-Minkowski inequality for the star duals for the Lp radial sum.Furthermore,we give some Brunn-Minkowski inequalities for the star duals of intersection bodies for the Lp ... In this paper,we first establish the dual Brunn-Minkowski inequality for the star duals for the Lp radial sum.Furthermore,we give some Brunn-Minkowski inequalities for the star duals of intersection bodies for the Lp radial sum and the Lp harmonic Blaschke sum. 展开更多
关键词 star dual Brunn-Minkowski inequality intersection body Lp radial sum Lp harmonic Blaschke sum
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Wave Drift Forces on Two Floating Bodies Arranged Side by Side 被引量:1
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作者 段文洋 赵彬彬 《Journal of Marine Science and Application》 2011年第4期394-398,共5页
An innovative hydrodynamic theory and numerical model were developed to help improve the efficiency, accuracy, and convergence of the numerical prediction of wave drift forces on two side-by-side deepwater floating bo... An innovative hydrodynamic theory and numerical model were developed to help improve the efficiency, accuracy, and convergence of the numerical prediction of wave drift forces on two side-by-side deepwater floating bodies. The wave drift forces were expressed by the double integration of source strength and the corresponding Green function on the body surface, which is consistent with the far field formula based on momentum conservation and sharing the advantage of near field calculations providing the drift force on each body. Numerical results were validated through comparing the general far field model and pressure integral model, as well as the middle field model developed usin^z the software HydroStar. 展开更多
关键词 wave drift forces floating body side by side panel method
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Asymptotic properties of two affine invariants for 1-unconditional convex bodies
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作者 谢富生 何斌吾 易军 《Journal of Shanghai University(English Edition)》 CAS 2010年第3期223-227,共5页
Let K be a 1-unconditional convex bodies in Euclidean spaces.We study the asymptotic properties of two affine invariants m2(K) and S2(K) for a random simplex inside K.As an application,we discuss the asymptotic pr... Let K be a 1-unconditional convex bodies in Euclidean spaces.We study the asymptotic properties of two affine invariants m2(K) and S2(K) for a random simplex inside K.As an application,we discuss the asymptotic properties of two affine invariants m2(Bpn ) and S2(Bpn ),where Bpn = {x ∈ Rn : ‖x‖ p 1}. 展开更多
关键词 convex body 1-unconditional convex body isotropic constant Sylvester’s problem random simplex
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A novel binary effective medium model to describe the prepeak stressstrain relationship of combined bodies of rock-like material and rock 被引量:2
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作者 Tienan Wang Yue Zhai +2 位作者 Huan Gao Yubai Li Ruifeng Zhao 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第5期601-616,共16页
Combined bodies of rock-like material and rock are widely encountered in geotechnical engineering,such as tunnels and mines.The existing theoretical models describing the stress-strain relationship of a combined body ... Combined bodies of rock-like material and rock are widely encountered in geotechnical engineering,such as tunnels and mines.The existing theoretical models describing the stress-strain relationship of a combined body lack a binary feature.Based on effective medium theory,this paper presents the governing equation of the“elastic modulus”for combined and single bodies under triaxial compressive tests.A binary effective medium model is then established.Based on the compressive experiment of concretegranite combined bodies,the feasibility of determining the stress threshold based on crack axial strain is discussed,and the model is verified.The model is further extended to coal-rock combined bodies of more diverse types,and the variation laws of the compressive mechanical parameters are then discussed.The results show that the fitting accuracy of the model with the experimental curves of the concretegranite combined bodies and various types of coal-rock combined bodies are over 95%.The crack axial strain method can replace the crack volumetric strain method,which clarifies the physical meanings of the model parameters.The variation laws of matrix parameters and crack parameters are discussed in depth and are expected to be more widely used in geotechnical engineering. 展开更多
关键词 Combined body stress-strain relationship Hooke’s law Effective medium theory Stress threshold determination
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Canonical Treatments for the Two Bodies Problem with Varying Mass Taking into Consideration the Periastron Effect
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作者 M. I. El-Saftawy Amirah R. Algethami 《International Journal of Astronomy and Astrophysics》 2014年第1期70-79,共10页
In this work, the Hamiltonian of the two body problem with varying mass was developed in the extended phase space taking into consideration the periastron effects. The short period solution was obtained through constr... In this work, the Hamiltonian of the two body problem with varying mass was developed in the extended phase space taking into consideration the periastron effects. The short period solution was obtained through constructing a second order canonical transformation using “Hori’s” method developed by “Kamel”. The elements of the transformation as well as the inverse transformation were obtained too. The final solution of the problem was derived using “Delva-Hanslmeier” method. 展开更多
关键词 two Body with VARYING MASS PERTURBATION Hori’s Method
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Fast forward modeling of gravity anomalies for two-dimensional bodies of arbitrary shape and density distribution
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作者 Chen Xin Chen Long-Wei +1 位作者 Luo Tian-Ya Xiong Bin 《Applied Geophysics》 SCIE CSCD 2020年第5期776-783,902,903,共10页
A fast and high precision spatial domain algorithm is presented for forward modeling of two-dimensional(2D)body gravity anomalies of arbitrary shape and density distribution.The new algorithm takes advantage of the co... A fast and high precision spatial domain algorithm is presented for forward modeling of two-dimensional(2D)body gravity anomalies of arbitrary shape and density distribution.The new algorithm takes advantage of the convolution properties of the expression for 2D gravity anomalies,uses a rectangular cell as a grid subdivision unit,and then 2D bodies with irregular cross-sections are approximated by a combination of 2D bodies with a rectangular cross section.The closed-form expression is used to calculate the gravitational anomalies of the combination of 2D bodies with a rectangular cross section.To improve computing effi ciency,the new algorithm uses a fast algorithm for the implementation of the Toeplitz matrix and vector multiplication.The synthetic 2D models with rectangular and circular cross-sections and constant and variable densities are designed to evaluate the computational accuracy and speed of the new algorithm.The experiment results show that the computation costs less than 6 s for a grid subdivision with 10000×10000 elements.Compared to the traditional forward modeling methods,the proposed method significantly improved computational effi ciency while guaranteeing computational accuracy. 展开更多
关键词 two-dimensional bodies gravity anomalies forward modeling Toeplitz matrix
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Automated Extraction for Water Bodies Using New Water Index from Landsat 8 OLI Images 被引量:3
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作者 Pu YAN Yue FANG +2 位作者 Jie CHEN Gang WANG Qingwei TANG 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第1期59-75,共17页
The extraction of water bodies is essential for monitoring water resources,ecosystem services and the hydrological cycle,so analyzing water bodies from remote sensing images is necessary.The water index is designed to... The extraction of water bodies is essential for monitoring water resources,ecosystem services and the hydrological cycle,so analyzing water bodies from remote sensing images is necessary.The water index is designed to highlight water bodies in remote sensing images.We employ a new water index and digital image processing technology to extract water bodies automatically and accurately from Landsat 8 OLI images.Firstly,we preprocess Landsat 8 OLI images with radiometric calibration and atmospheric correction.Subsequently,we apply KT transformation,LBV transformation,AWEI nsh,and HIS transformation to the preprocessed image to calculate a new water index.Then,we perform linear feature enhancement and improve the local adaptive threshold segmentation method to extract small water bodies accurately.Meanwhile,we employ morphological enhancement and improve the local adaptive threshold segmentation method to extract large water bodies.Finally,we combine small and large water bodies to get complete water bodies.Compared with other traditional methods,our method has apparent advantages in water extraction,particularly in the extraction of small water bodies. 展开更多
关键词 water bodies extraction Landsat 8 OLI images water index improved local adaptive threshold segmentation linear feature enhancement
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Numerical Simulation of TWo Different Flexible Bodies Immersed in Moving Flow
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作者 王思莹 黄明海 尹协振 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第8期98-101,共4页
The coupled motion of two flexible bodies with different lengths immersed in moving fluid is studied numerically. The flapping frequency, flapping amplitude and average drag coefficient of each body are calculated and... The coupled motion of two flexible bodies with different lengths immersed in moving fluid is studied numerically. The flapping frequency, flapping amplitude and average drag coefficient of each body are calculated and the influences of the arranging manner and separation distance are analyzed. In our simulation, when placed in the flow individually, the flexible body with a longer length will flap in period and the shorter one will maintain still straightly in the flow direction. The numerical results show that, two different flexible structures near placed in moving flow would strongly interact. When they are placed side by side, the existence of the stable shorter flexible body will restrain the flapping of the longer one while the existence of the longer flexible body may also induce the shorter one to flap synchronously. When placed in tandem with the shorter flexible body in upstream, the flapping of the longer one in downstream will be obviously enhanced. In the situation for the longer flexible body placed in upstream of the shorter one, the coupled flapping amplitude and average drag coefficients increase and decrease periodically with increasing the arranging space, and peak values appear as a result of the mediate of the tail wakes. 展开更多
关键词 FLEXIBLE In Numerical Simulation of two Different Flexible bodies Immersed in Moving Flow
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Effect of Resonance on the Motion of Two Cylindrical Rigid Bodies
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作者 M. R. Hassan Baby Kumari +2 位作者 Md. Aminul Hassan Payal Singh B. K. Sharma 《International Journal of Astronomy and Astrophysics》 2016年第4期555-574,共20页
The effect of resonance on the motion of two cylindrical rigid bodies has been studied in the light of Bhatnagar [1] [2] [3] and under some defined axiomatic restrictions. Here we have calculated variation in Eulerian... The effect of resonance on the motion of two cylindrical rigid bodies has been studied in the light of Bhatnagar [1] [2] [3] and under some defined axiomatic restrictions. Here we have calculated variation in Eulerian angles due to resonance in terms of orbital elements and unperturbed Eulerian angles. 展开更多
关键词 Inertia Ellipsoid Ellipsoids of Revolution Symmetrical bodies Orientation of the bodies Principal Axes Eulerian Angles Critical Points Perturbations Averaging of Hamiltonian RESONANCE
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