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Computing the Far-Field Scattered by a Spherical Target Near the Seabed
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作者 Natalie S.Grigorieva Fiodor F.Legusha Kirill S.Safronov 《哈尔滨工程大学学报(英文版)》 2025年第5期1019-1026,共8页
This study proposes a numerically efficient technique for computing the far-field scattered by a spherical target placed near the seabed.The bottom is supposed to be a homogeneous liquid attenuating half-space.The tra... This study proposes a numerically efficient technique for computing the far-field scattered by a spherical target placed near the seabed.The bottom is supposed to be a homogeneous liquid attenuating half-space.The transmitter and receiver are situated at different points of a homogeneous water half-space.The distances between the transmitter,receiver,and object of interest are assumed to be much larger than the acoustic wavelength in water.The scattered far-field is ascertained using Hackman and Sammelmann’s general approach.The arising scattering coefficients of a sphere are assessed using the steepest descent approach.The branch cut contribution is also considered.The obtained formulas for the form-function can be used for acoustically rigid or soft scatterers,as well as elastic targets or spherical elastic shells.Numerical simulations are conducted for an acoustically rigid sphere.Asymptotic expressions for the scattering coefficients allow a decrease in the number of summands in the formula for the target strength and a significant reduction in computational time. 展开更多
关键词 Scattering of acoustic waves Spherical scatterer Attenuating liquid bottom Later wave Target strength
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Enhancing Evaporative Cooler Efficiency through Magnetized Water and Heat Exchanger Optimization
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作者 Mohammed J.Alshukri Amjed Al-Khateeb +2 位作者 Ahmed Mohsin Alsayah Adel A.Eidan Hameed B.Mahood 《Energy Engineering》 2025年第4期1359-1372,共14页
This research presents a new method to boost the efficiency of evaporative coolers by integrating magnetized water and a heat exchanger.Magnetized water,known for its high evaporation rate and reduced surface tension,... This research presents a new method to boost the efficiency of evaporative coolers by integrating magnetized water and a heat exchanger.Magnetized water,known for its high evaporation rate and reduced surface tension,offers a promising way to enhance air cooler performance.Additionally,the advanced heat exchanger both improves air cooling capacity and controls humidity levels.Aloni 100 L,a locally manufactured evaporative cooling system,and tap water were used in experiments.Tap water was magnetized using recycled magnets extracted from computer hard drives.Twenty-six magnets meticulously arranged within rectangular grooves,each with a minimum strength of 0.5 to 1T,were used tomagnetize tapwater.Our experiments showa significant rise in cooling efficiency,with magnetized water increasing from 70.62%to 91.43%.In a similar vein,adding the heat exchanger leads to a significant improvement,raising the cooling efficiency from 69.44%to 93.96%.Furthermore,the combined use of magnetized water and a heat exchanger results in exceptional performance,increasing cooling efficiencies by 29.5%and 35.3%compared to using only magnetized water or only a heat exchanger,respectively.This study also explores the largely untapped potential of magnetized water,providing valuable insights into its effects on water properties and its broader applications in various fields.These findings represent a significant advancement in air cooling technology and pave the way for more energy-efficient and sustainable solutions. 展开更多
关键词 Evaporative cooling magnetized water heat exchanger air cooler subtropical weather
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Ship Detection Based on Improved SDD Algorithm 被引量:2
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作者 Hongcheng Chu Tianhu Wang +4 位作者 Qiannian Miao Zeran Chen Rong Wang Wenjie Li Tao Huang 《Instrumentation》 2024年第4期35-43,共9页
To address the issue of inadequate detection performance for small and mediumsized densely packed vessels in ship target detection,this paper proposes an improved Single Shot Multibox Detector(SSD)model to achieve mor... To address the issue of inadequate detection performance for small and mediumsized densely packed vessels in ship target detection,this paper proposes an improved Single Shot Multibox Detector(SSD)model to achieve more accurate detection.The algorithm redesigns the anchor boxes to fit the ship target detection dataset better and integrates the Squeeze-and-Excitation(SE)module into the Visual Geometry Group(VGG)network to enhance the channel features of the input feature maps.Additionally,the network's ability to perceive and represent important features is further enhanced by introducing the Convolutional Block Attention Module(CBAM),which is responsible for channel and spatial attention mechanisms.Finally,the feature pyramid module is employed to fuse six layers of features from the original network,thereby improving the SSD network's capability to detect small and occluded densely packed vessel targets.The experimental results show that the model's target recognition ability for fishing vessels improved from 58.07%to 65.87%;for patrol boats,the ability increased from 94.6%to 96.03%;and for inflatable boats,it rose from 72.08%to 74.93%.The overall mean Average Precision(mAP)also increased from the original model's 80.04%to 81.22%.Additionally,by clustering prior boxes,more suitable prior boxes for vessel detection were obtained,enhancing the model's perception capabilities for both large and small vessels. 展开更多
关键词 target detection SHIP feature fusion SDD
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Abnormal Action Detection Based on Parameter-Efficient Transfer Learning in Laboratory Scenarios
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作者 Changyu Liu Hao Huang +2 位作者 Guogang Huang Chunyin Wu Yingqi Liang 《Computers, Materials & Continua》 SCIE EI 2024年第9期4219-4242,共24页
Laboratory safety is a critical area of broad societal concern,particularly in the detection of abnormal actions.To enhance the efficiency and accuracy of detecting such actions,this paper introduces a novel method ca... Laboratory safety is a critical area of broad societal concern,particularly in the detection of abnormal actions.To enhance the efficiency and accuracy of detecting such actions,this paper introduces a novel method called TubeRAPT(Tubelet Transformer based onAdapter and Prefix TrainingModule).Thismethod primarily comprises three key components:the TubeR network,an adaptive clustering attention mechanism,and a prefix training module.These components work in synergy to address the challenge of knowledge preservation in models pretrained on large datasets while maintaining training efficiency.The TubeR network serves as the backbone for spatio-temporal feature extraction,while the adaptive clustering attention mechanism refines the focus on relevant information.The prefix training module facilitates efficient fine-tuning and knowledge transfer.Experimental results demonstrate the effectiveness of TubeRAPT,achieving a 68.44%mean Average Precision(mAP)on the CLA(Crazy LabActivity)small-scale dataset,marking a significant improvement of 1.53%over the previous TubeR method.This research not only showcases the potential applications of TubeRAPT in the field of abnormal action detection but also offers innovative ideas and technical support for the future development of laboratory safety monitoring technologies.The proposed method has implications for improving safety management systems in various laboratory environments,potentially reducing accidents and enhancing overall workplace safety. 展开更多
关键词 Parameter-efficient transfer learning laboratory scenarios TubeRAPT abnormal action detection
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Microbiological and Physico-Chemical Analysis of the Waters of the “Mamouwol” Stream in the Urban District of Mamou (Republic of Guinea)
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作者 Mamadou Lamarana Souare Mamadou Madaniou Sow +1 位作者 Saran Camara Adama Moussa Sakho 《Journal of Water Resource and Protection》 CAS 2024年第8期559-568,共10页
Water is essential to life and to the sustainable socio-economic development of a nation, It is therefore interesting to have a better knowledge of the quality of this water. The aim was to determine the degree of mic... Water is essential to life and to the sustainable socio-economic development of a nation, It is therefore interesting to have a better knowledge of the quality of this water. The aim was to determine the degree of microbiological and physico-chemical pollution of the water of the “Mamouwol” river in the town of Mamou. To do this, we chose four (4) sampling sites spread throughout the town of Mamou. During the month of March (2024), 4 water samples were analyzed to monitor the water quality of this river. The average values of the flora analyzed show that these water are heavily contaminated with bacteria indicative of fecal and metal pollution. This study showed that sites: Mam4;Mam2 and Mam1 contain the highest loads, with Total Coliform counts ranging from 1534 CFU/100 ml to 2100 CFU/100 ml, the number of faecal coliforms varies between 526 and 1240 CFU/100 ml, and that of faecal streptococci between 526 and 841 CFU/100 ml. Metal content, BOD5 and COD all comply with the laboratory’s analysis criteria, although they vary from point to point. 展开更多
关键词 Pollution Water Watercourses Waterborne Diseases Microbiological Analysis
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Comparative Study of Satellite Precipitation and Synoptic Observations in the Republic of Guinea
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作者 Mamadou Saliou Diallo Amadou Lamarana Bah +2 位作者 Fatoumata Sylla Ibrahima Kalil Kante Idrissa Diaby 《Journal of Energy and Power Engineering》 CAS 2024年第3期104-118,共15页
This research work involves a comparative study of satellite rainfall and synoptic observations in the Republic of Guinea over a 30-year period.The methodology used consists,firstly,in assessing rainfall trends over t... This research work involves a comparative study of satellite rainfall and synoptic observations in the Republic of Guinea over a 30-year period.The methodology used consists,firstly,in assessing rainfall trends over the study period in Guinea’s four natural regions,using the temporal averages of the three stations located in each region.Secondly,we calculated the correlations between synoptic and satellite observation data,in order to determine the links between them on the basis of data analysis.The results for synoptic stations on average seasonal rainfall cycles and satellite products show that in Lower Guinea,the CRU(Climatic Research Unit)and GPCC(Global Precipitation Climatology Center)data are good estimates of observations.In the Fouta Djallon region,they also estimate observations well,but at two synoptic stations,with the exception of Mamou,they underestimate them.In Upper Guinea,during the monsoon period,satellites give a good estimate of rainfall in this area.In the forest region,these products show highly variable behavior,sometimes underestimating and sometimes overestimating observations,depending on the stations in the zone. 展开更多
关键词 PRECIPITATION OBSERVATION satellite data synoptic station
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Assessment of Upper Guinea’s Wind Energy Potential with a View to Identifying Exploitable Sites
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作者 Nènè Aïssata Baldé Amadou Lamarana Bah +2 位作者 Idrissa Diaby Cellou Kanté Adama Moussa Sakho 《Journal of Energy and Power Engineering》 CAS 2024年第1期9-17,共9页
As part of the national strategy to further develop the wind energy sector,the eight prefectures of Upper Guinea have been selected.Using meteorological data recorded over thirty years(1991-2021)at a height of 20 m,we... As part of the national strategy to further develop the wind energy sector,the eight prefectures of Upper Guinea have been selected.Using meteorological data recorded over thirty years(1991-2021)at a height of 20 m,we assessed wind resources in terms of characteristic speeds,power and available energy.To this end,the Weibull distribution method was used and the following values were obtained:3.66 m/s for the average speed;1,102.83 W/m^(2)for the available power and 8,747.06 kWh/m^(2)/year for the annual available energy. 展开更多
关键词 Wind energy Weibull distribution high Guinea
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Quantifying Corrosion Rate in Oil and Gas Wells by Measuring Alloying Constituents in Produced Water
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作者 Joseph J. Puthuvelil Fayez A. Al Ammarie Awad H. Malki 《Journal of Materials Science and Chemical Engineering》 2024年第12期1-17,共17页
Most oil and gas wells worldwide are completed with low alloy carbon steel due to cost-effectiveness, despite its high susceptibility to corrosion. Corrosion in alloy steels occurs through galvanic or electrolytic rea... Most oil and gas wells worldwide are completed with low alloy carbon steel due to cost-effectiveness, despite its high susceptibility to corrosion. Corrosion in alloy steels occurs through galvanic or electrolytic reactions, resulting in the release of metallic ions. This release adversely affects the strength and integrity of production tubing. The current study focused on quantifying the amount of alloying constituents present in the produced waters of oil and gas wells using inductively coupled plasma-optical emission spectroscopy (ICP-OES) to calculate the corrosion rate on the production tubing. Two types of alloy steel tubing, API 5CT T-95 and API 5CT J55, were selected. The wells were chosen based on sweet and sour production. The levels of ions present in the produced water—Nickel, Chromium, Manganese, Molybdenum, and Iron—were measured. Ion dissolution was converted to corrosion rate using the exposed area of the tubing and the water flow rate. The study concluded that a very high corrosion rate occurs in sweet wells completed with T-95 metallurgy, whereas the corrosion rate in sour gas producers is significantly less compared to sweet producers. For the oil wells, although they are sour producers, a very low corrosion rate was observed with API 5CT J55 metallurgy. Furthermore, the study revealed that quantifying the alloying constituents in produced water is key to developing suitable corrosion projection approaches, predicting the service life of production tubing in gas and oil wells and metallic structures, and guiding production engineers to make informed decisions and timely responses to corrosion threats before failure. 展开更多
关键词 Produced Water ICP-OES Ion Dissolution Alloy Steel Oil & Gas Wells Corrosion Rate Saturation Index
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Corrosion and Scaling Threat in Upstream Oil Operation
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作者 Nasir Ullattumpoyil Talal M. Al-Ghamdi Nasser R. Al-Hajri 《World Journal of Engineering and Technology》 2024年第2期426-437,共12页
Corrosiveness or scaling is an inherent threat to oil operations. The primary cause for this threat is the presence of water having complex geochemical matrix. Unanticipated water production, particularly if it contai... Corrosiveness or scaling is an inherent threat to oil operations. The primary cause for this threat is the presence of water having complex geochemical matrix. Unanticipated water production, particularly if it contains unwanted impurities, can significantly impact hydrocarbon production. The current paper discusses the degree of threat posed to oil operation facilities based on the water characteristics. Methodology involved the collection and analysis of water samples from major sources in oil industry such as groundwater, wellheads and seawater. The parameters tested include geochemical, microbiological and pollutants. The lab data was used to develop scaling and corrosion prediction indices such as Langelier Saturation Index (LSI), Ryznar Stability Index (RSI) and Puckorius Scaling Index (PSI). The study indicated varying water chemistry for different sources. Mixing of those waters may lead to ionic saturation and scaling in different facilities. Presence of the SRB and GAB in some water sources also posed threat to water system by forming fouling and corrosion. Seawater used for offshore oilfields water injection to maintain reservoir pressure and improve oil recovery showed scaling tendency, whereas under different reservoir pressure, it can cause corrosion. Some of the samples also had corrosion residuals such as iron, which indicated active corrosion. Current study showed higher alkalinity with high sulfate for one groundwater sample with presence of active corrosion residuals such as dissolved iron and manganese. The study showed positive value for LSI which indicated supersaturation of the water samples with respect to calcium carbonate (CaCO<sub>3</sub>) and scale forming. Similarly, for RSI and PSI, the value was below six which confirmed the scaling potential for all the samples. Even though the index value was pointing towards scaling potential, the geochemistry, microbiology and presence of other impurities indicated corrosion threat to the oil and gas industrial facilities. The study concluded the importance of different scale inhibition mechanism and corrosion control in Oil and Gas industry. 展开更多
关键词 Formation Water Petroleum Reservoirs GROUNDWATER Saturation Indices Corrosiveness
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Overview of Jute Fibre as Thermoplastic Matrix Polymer Reinforcement
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作者 Tezara Cionita Mohammad Hazim Mohamad Hamdan +9 位作者 Januar Parlaungan Siregar Deni Fajar Fitriyana Ramli Junid Wong Ling Shing Jamiluddin Jaafar Agustinus Purna Irawan Teuku Rihayat Rifky Ismail Athanasius Priharyoto Bayuseno Emilianus Jehadus 《Journal of Renewable Materials》 EI CAS 2024年第3期457-483,共27页
Recent decades have seen a substantial increase in interest in research on natural fibres that is aligned with sustainable development goals(SDGs).Due to their renewable resources and biodegradability,natural fiberrei... Recent decades have seen a substantial increase in interest in research on natural fibres that is aligned with sustainable development goals(SDGs).Due to their renewable resources and biodegradability,natural fiberreinforced composites have been investigated as a sustainable alternative to synthetic materials to reduce the usage of hazardous waste and environmental pollution.Among the natural fibre,jute fibre obtained from a bast plant has an increasing trend in the application,especially as a reinforcement material.Numerous research works have been performed on jute fibre with regard to reinforced thermoset and thermoplastic composites.Nevertheless,current demands on sustainable materials have required new developments in thermoplastic composites.In this paper,the author reviews jute plants as reinforcement materials for thermoplastic matrix polymers.This review provides an overview of the sustainability of jute plants as reinforcement material for thermoplastic matrix polymers.The overview on jute based thermoplastic composites focused on the thermal behavior and mechanical properties.Apart from physical,chemical,and mechanical properties,the study also covers the current and perspectives for future research challenges faced by the researchers on jute fibre reinforced thermoplastic composites. 展开更多
关键词 Jute fibre sustainable development goals(SDGs) natural fibre THERMOPLASTIC composite sustainable manufacturing
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Simulation of the Interaction between Driver and Seat 被引量:16
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作者 DU Xiaoming REN Jindong +1 位作者 SANG Chunlei LI Lemeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第6期1234-1242,共9页
Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface bet... Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface between human and seat, which can be obtained by simulation. But current simulation method focuses mainly on calculation itself other than combining it with posture prediction and cab packaging parameters, which cause it difficult to acquire accurate pressure calculation results without accurate posture of human body, and make it almost meaningless to design optimization. Therefore, a human body geometric model with posture change capability is built and linked up with Cascade Prediction Model(CPM), which takes cab packaging parameters as inputs. A detailed finite element model of driver human body is constructed and used to conduct the driver-seat interaction simulation between human body and seat. Good accordance of pressure distribution is observed between simulation and test, which validates the simulation. In addition to the distribution pattern, curves on key sections are used to analyze the pressure and shear stress on the seat surface, as well as soft tissue stress inside human body. The simulation shows that the maximum stress of buttocks locates under the ischial tuberosity, and the maximum stress of trunk occurs near the scapula posterior and the lower waist. These are the places where fatigue usually occurs. The maximum pressure of seat appears at the driver-seat contact area corresponding to the driver's maximum skin tissue stress. In order to guide the seat design and cab packaging and study the influence of posture to pressure distribution, finite element models for different levels of cab packaging parameters are created by using CPM. The pressure distributions are calculated and their tendencies varying with cab packaging parameters are obtained. The method presented provides a new way to accurately simulate the interaction between driver human body and seat, and to guide the seat design and cab packaging so as to improve seating comfort. 展开更多
关键词 seating comfort pressure distribution posture prediction model packaging parameters
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Preparation of cationic polyacrylamide microsphere emulsion and its performance for permeability reduction 被引量:11
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作者 Guo Aijun Geng Yiran +3 位作者 Zhao Lili Li Jun Liu Dong Li Peng 《Petroleum Science》 SCIE CAS CSCD 2014年第3期408-416,共9页
In this paper, cationic polyacrylamide microspheres (CPAM) were synthesized using acrylamide (AM) and methacryloyloxyethyl trimethyl ammonium chloride (TMAEMC) as monomers, ammonium sulfate as dispersant, poly(... In this paper, cationic polyacrylamide microspheres (CPAM) were synthesized using acrylamide (AM) and methacryloyloxyethyl trimethyl ammonium chloride (TMAEMC) as monomers, ammonium sulfate as dispersant, poly(acryloyloxyethyl trimethyl ammonium chloride) (PAETAC) as dispersion stabilizer, and ammonium persulfate as initiator. The synthetic method was dispersion polymerization. The effects of monomer ratio (AM/TMAEMC), dispersant concentration, and dispersion stabilizer dosage on dispersion polymerization were systematically studied to determine the optimal preparation conditions. The structure and viscosity of the synthesized polymer were characterized by FTIR and capillary viscometry, respectively, and the particle sizes and distribution of the polymer microspheres were characterized by microscopy and dynamic light scattering, respectively. Finally, flow tests were conducted to measure the permeability reduction performance of the microspheres at various concentrations in sand packs with different permeability. Results show that CPAM emulsion of a solids content of 1 wt% has excellent performance in low-to-medium permeability formations (〈 1,000 mD), and the efficiency may reach above 90%. 展开更多
关键词 Dispersion polymerization cationic polyacrylamide microspheres profile modification permeability reduction
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Development characteristics of the fault system and its control on basin structure, Bodong Sag, East China 被引量:5
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作者 Wu Zhiping Cheng Yanjun +4 位作者 Yan Shiyong Su Wen Wang Xin Xu Changgui Zhou Xinhuai 《Petroleum Science》 SCIE CAS CSCD 2013年第4期450-457,共8页
The Bodong Sag,located in the Bohai Sea,offshore China,is one of the most petroliferous basins in China.Based on three dimensional seismic reflection data and time slice data,we analyze the fault system of the Bodong ... The Bodong Sag,located in the Bohai Sea,offshore China,is one of the most petroliferous basins in China.Based on three dimensional seismic reflection data and time slice data,we analyze the fault system of the Bodong area in detail,establish the fault structure pattern of different types and summarize the distribution of the fault system.It is concluded that the development characteristics of the Cenozoic fault system are in accordance with the dextral stress field of the Tanlu Fault,which displayed a brush structure with NNE strike-slip faults as its principal faults,NE-trending extensional faults as secondary faults and EW-trending faults as minor faults.Faults can be divided into (1) strike-slip type,(2) extensional type,(3) strike-slip extensional type and (4) extensional strike-slip type.The spatial structures of different faults have obvious differences because of the fault properties and activity intensity.The fault system at different stages shows tremendous differences because of the transition of the Tanlu Fault from sinistral strike-slip to dextral strike-slip,the transition between extension and strike-slip,and the transition from mantle upwelling to thermal subsidence.According to the controlling effect of faults on basin structure,the Cenozoic basin experienced four evolutionary stages,(a) transition stage from sinistral strike-slip to dextral strike-slip,(b) strike-slip extensional faulted stage,(c) extensional strike-slip faulted stage and (d) strike-slip depression stage.The identification of temporal and spatial differences of faults could be used as a significant guideline for oil and gas exploration in the Bodong area. 展开更多
关键词 Fault system basin structure Bodong area
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Quantitative research of diagenesis:its effect on pore evolution of the Fuyu oil reservoir in the north Qijia region 被引量:5
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作者 HAO Guoli SHAN Xuanlong +1 位作者 LIU Wanzhu WANG Qingbin 《Mining Science and Technology》 EI CAS 2010年第5期770-777,共8页
From observing cores of 18 wells,identifying 175 ordinary thin sections and 61 thin casting sections,energy spectrum analyses of 37 samples,homogenization temperature measurement of fluid inclusions of 11 samples,we d... From observing cores of 18 wells,identifying 175 ordinary thin sections and 61 thin casting sections,energy spectrum analyses of 37 samples,homogenization temperature measurement of fluid inclusions of 11 samples,we determine the types of diagenesis and pores of the Fuyu oil reservoir in the north Qijia region.We classified the pores and measured their plane porosity using CIA 2000,the software of rock image analysis,calculated the effect of different kinds of diagenesis on porosity,studied the controlling actions of diagenesis to pore evolution quantitatively,combined with burial history,thermal history and their diagenetic environments.Our results show that mechanical compaction and carbonate cementation are the major destructive diagenesed,developed during early diagenesis stages.The reduction in porosity by mechanical compaction and carbonate cementation are about 25% and 8%,while the destructive intensity of siliceous cementation and clay mineral cementation is relatively much smaller,i.e.,the reduction of porosity is about 2% and 0.2% Dissolution is constructive diagenesis,the increment of porosity is about 6%.There are four diagenesis evolution stages,during which the porosity reduced from 30%~38% to 2%~20%.Mechanical compaction and early cementation are the main diageneses in the early diagenesis stages,when porosity was reduced to 2%~10%.Dissolution is the main diagenesis of an A I substage of the middle diagenesis stage,when porosity increased 1%~8%.The dissolution of the A Ⅱ substage of the middle diagenesis stage affected by late cementation,raised porosity 1%~5%.The porosity varied slightly during the middle stage B. 展开更多
关键词 north Qijia region Fuyu oil reservoir DIAGENESIS pore evolution quantitative research
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A General Channel Model for Visible Light Communications in Underground Mines 被引量:7
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作者 Jia Wang Ahmed Al-Kinani +2 位作者 Wensheng Zhang Cheng-Xiang Wang Li Zhou 《China Communications》 SCIE CSCD 2018年第9期95-105,共11页
In underground mines, visible light communication(VLC) system is a promising method to realize effective communication,which supports communication and illumination at the same time. Therefore, adequate research of un... In underground mines, visible light communication(VLC) system is a promising method to realize effective communication,which supports communication and illumination at the same time. Therefore, adequate research of underlying physical propagation phenomenon should be carried out to realize VLC system in underground mines. To design VLC system and evaluate its performance, accurate and efficient channel models, including large-scale fading and scattering characteristics, are needed to be established. However,the characteristics of the underlying VLC channels about fading and scattering have not been sufficiently investigated yet. In this paper, a path loss channel model, based on the recursive model, is proposed precisely. Its path loss exponent is determined by three different trajectories, which is studied in the mining roadway and working face environment. Besides, the shadowing effect for VLC has been modelled by a Bimodal Gaussian distribution in underground mines. Considering the number of transmitters in line-of-sight(Lo S) as well as non-line-of-sight(NLo S) scenarios,our simulation illustrates the fact that, as the curve fitting technique is employed, the path loss displays a linear behavior in log-domain.The path loss expression is derived, it is related to the distance. Finally, root mean square(RMS) delay spread and Mie scattering in underground mines are analyzed. 展开更多
关键词 underground mines visible light communications channel modeling path loss SHADOWING delay spread.
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Management of hepatocellular carcinoma rupture in the caudate lobe 被引量:3
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作者 De-Fei Hong Ying-Bin Liu +5 位作者 Shu-You Peng Jin-Zhong Pang Zhi-Fei Wang Jian Cheng Guo-Liang Shen Yuan-Biao Zhang 《World Journal of Gastroenterology》 SCIE CAS 2015年第26期8163-8169,共7页
AIM: To demonstrate that caudate lobectomy is a valid treatment in cases of hepatocellular carcinoma(HCC) rupture in the caudate lobe based on our experience with the largest case series reported to date.METHODS: A re... AIM: To demonstrate that caudate lobectomy is a valid treatment in cases of hepatocellular carcinoma(HCC) rupture in the caudate lobe based on our experience with the largest case series reported to date.METHODS: A retrospective study of eight patients presenting with spontaneous rupture and hemorrhage of HCC in the caudate lobe was conducted.Two patients underwent ineffective transarterial embolization preoperatively.Caudate lobectomy was performed in all eight patients.Bilateral approach was taken in seven cases for isolated complete caudate lobectomy.Left-sided approach was employed in one case for isolated partial caudate lobectomy.Transarterial chemoembolization was performed postoperatively in all patients.RESULTS: Caudate lobectomy was successfully completed in all eight cases.The median time delay from the diagnosis to operation was 5 d(range: 0.25-9).Median operating time was 200 min(range: 120-310) with a median blood loss of 900 m L(range: 300-1500).Five patient remained in long-term follow-up,with one patient becoming lost to followup at 3 years and two patients currently alive at 7 and 19 mo.One patient required reoperation due to recurrence.Gamma knife intervention was performed for brain metastasis in another case.Two patients survived for 10 and 84 mo postoperatively,ultimately succumbing to multiple organ metastases.CONCLUSION: Caudate lobectomy is the salvage choice for HCC rupture in the caudate lobe.Local anatomy and physiologic features of the disease render caudate lobectomy a technically difficult operation.Postponement of surgical intervention is thus recommended while the rupture remains hemodynamically stable until an experienced surgeon becomes available.Prognosis is confounded by numerous factors,but long-term survival can be expected in the majority of cases. 展开更多
关键词 CAUDATE LOBECTOMY HEPATOCELLULAR carcinoma EMERGENCY RUPTURE transarterial EMBOLIZATION
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An efficient hybrid evolutionary optimization algorithm based on PSO and SA for clustering 被引量:11
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作者 Taher NIKNAM Babak AMIRI +1 位作者 Javad OLAMAEI Ali AREFI 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第4期512-519,共8页
The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the Kmeans algorithm depends highly on initial cluster centers and converges to local minima. This paper prop... The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the Kmeans algorithm depends highly on initial cluster centers and converges to local minima. This paper proposes a hybrid evolutionary programming based clustering algorithm, called PSO-SA, by combining particle swarm optimization (PSO) and simulated annealing (SA). The basic idea is to search around the global solution by SA and to increase the information exchange among particles using a mutation operator to escape local optima. Three datasets, Iris, Wisconsin Breast Cancer, and Ripley's Glass, have been considered to show the effectiveness of the proposed clustering algorithm in providing optimal clusters. The simulation results show that the PSO-SA clustering algorithm not only has a better response but also converges more quickly than the K-means, PSO, and SA algorithms. 展开更多
关键词 Simulated annealing (SA) Data clustering Hybrid evolutionary optimization algorithm K-means clustering Parti-cle swarm optimization (PSO)
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Disposal and Use of Sewage on Agricultural Lands in Pakistan: A Review 被引量:7
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作者 G. MURTAZA A. GHAFOOR +4 位作者 M. QADIR G. OWENS M. A. AZIZ M. H. ZIA SAIFULLAH 《Pedosphere》 SCIE CAS CSCD 2010年第1期23-34,共12页
Raw sewage is widely used on agricultural soils in urban areas of developing countries to meet water shortages. Although it is a good source of plant nutrients, such sewage also increases the heavy metal load to soils... Raw sewage is widely used on agricultural soils in urban areas of developing countries to meet water shortages. Although it is a good source of plant nutrients, such sewage also increases the heavy metal load to soils, which may impact the food chain. Management options for sewage contaminated soils includes addition of nontoxic compounds such as lime, calcium sulfate and organic matter, which form insoluble metal complexes, thus reducing metal phytoavailability to plants. In this paper we review the variation in irrigation quality of sewage at different sites and its impact on the quality of soils and vegetables. Although quality of sewage was highly variable at source, yet the effluent from food industries was relatively safe for irrigation. In comparison effluent samples collected from textile, dyeing, calendaring, steel industry, hospitals and clinical laboratories, foundries and tanneries were hazardous with respect to soluble salts, sodium adsorption ratio and heavy metals like zinc, copper, iron, manganese, nickel, cobalt and cadmium. The sewage quality in main drains was better than that at the industry outlet, but was still not safe for irrigation. In general, higher accumulation of metals in fruits and vegetable roots was recorded compared to that in plant leaves, Edible parts of vegetables (fruits and/or leaves) accumulated metals more than the permissible limits despite the soils contained ammonium bicarbonate diethylenetriaminepentaacetie acid extractable metals within a safe range. In either case further scientific investigations are needed to ensure safe management strategies. Cadmium appeared to be the most threatening metal especially in leafy vegetables. It is advisable to avoid leafy vegetables cultivation in sewage irrigated areas everywhere to restrict its entry into food chain. 展开更多
关键词 CONTAMINATION heavy metals IRRIGATION soil quality VEGETABLES
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Optimal setting and placement of FACTS devices using strength Pareto multi-objective evolutionary algorithm 被引量:2
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作者 Amin Safari Hossein Shayeghi Mojtaba Bagheri 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第4期829-839,共11页
This work proposes a novel approach for multi-type optimal placement of flexible AC transmission system(FACTS) devices so as to optimize multi-objective voltage stability problem. The current study discusses a way for... This work proposes a novel approach for multi-type optimal placement of flexible AC transmission system(FACTS) devices so as to optimize multi-objective voltage stability problem. The current study discusses a way for locating and setting of thyristor controlled series capacitor(TCSC) and static var compensator(SVC) using the multi-objective optimization approach named strength pareto multi-objective evolutionary algorithm(SPMOEA). Maximization of the static voltage stability margin(SVSM) and minimizations of real power losses(RPL) and load voltage deviation(LVD) are taken as the goals or three objective functions, when optimally locating multi-type FACTS devices. The performance and effectiveness of the proposed approach has been validated by the simulation results of the IEEE 30-bus and IEEE 118-bus test systems. The proposed approach is compared with non-dominated sorting particle swarm optimization(NSPSO) algorithm. This comparison confirms the usefulness of the multi-objective proposed technique that makes it promising for determination of combinatorial problems of FACTS devices location and setting in large scale power systems. 展开更多
关键词 STRENGTH PARETO multi-objective evolutionary algorithm STATIC var COMPENSATOR (SVC) THYRISTOR controlled series capacitor (TCSC) STATIC voltage stability margin optimal location
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Effect of spleen-invigorating, Qi-replenishing and blood-arresting formula on zebrafish models with simvastatin-induced hemorrhage caused by spleen failing to control blood, in terms of theory of Traditional Chinese Medicine 被引量:2
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作者 Gao Chong Wang Jun +8 位作者 Wang Jia Zhu Xiaoyu Zhu Changle Guo Shengya Wang Chong Fan Qiuyue Zhang Jianuo Xia Bo Chen Xinyi 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2018年第3期399-405,共7页
OBJECTIVE: To investigate the hemostasis effect of spleen-invigorating, Qi-replenishing and blood-arresting formula, on a zebrafish models with simvastatin-induced hemorrhage, and with symptom pattern caused by spleen... OBJECTIVE: To investigate the hemostasis effect of spleen-invigorating, Qi-replenishing and blood-arresting formula, on a zebrafish models with simvastatin-induced hemorrhage, and with symptom pattern caused by spleen failing to control blood, in terms of theory of Traditional Chinese Medicine(TCM).METHODS: In the first experiment, 60 AB strain wild type zebrafishes were randomly assigned into two groups: normal group and model group. The model group was treated with 50 μM simvastatinfor 24 h. The second experiment: The melanin allele mutated Albino strain zebrafishes were divided into normal, model, A group and B group. The observational parameters were as follows: blood flow, velocity of movement, hemorrhage ratio and improvement ratio of hemorrhage.RESULTS: Hemorrhage ratio: in the first experiment, brain hemorrhage ratio was 75%. In the second experiment, heart hemorrhage ratio was 65%.Blood flow: compared with the normal group,there was a significantly decrease in the model group(P < 0.001). Velocity of movement: in the first experimental, compared with the normal group,there was a significantly decrease in the model group(P < 0.001). Improvement ratio of hemorrhage: agents A had little effect in heart hemorrhage of the zebrafish; agents B could reduce heart hemorrhage ratio of the zebrafish, and increase the improvement ratio of hemorrhage.CONCLUSION: The manifestation of zebrafish model with simvastatin-induced hemorrhage is basically similar to that of the clinical symptom pattern caused by spleen's failure to control blood. The Spleen-invigorating, Qi-replenishing and Blood-arresting Formula can reduce the heart hemorrhage ratio of zebrafish induced by simvastatin, and increase the Improvement ratio of hemorrhage. 展开更多
关键词 SIMVASTATIN HEMORRHAGE SPLEEN fail-ure governing BLOOD Reinforcing QI strengthening SPLEEN Reinforcing QI arresting bleeding ZEBRAFISH
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