The effects of wavelength-specific visible light, white light, and ultraviolet-B (UV-B, 280- 315 nm) on selected behaviors, grazing rate, spawning rate, and hatching rate of the marine copepod Calanus sinicus collecte...The effects of wavelength-specific visible light, white light, and ultraviolet-B (UV-B, 280- 315 nm) on selected behaviors, grazing rate, spawning rate, and hatching rate of the marine copepod Calanus sinicus collected from the Yellow Sea were studied. Calanus sinicus placed in a partitioned experimental system responded positively phototaxis to blue-cyan and yellow light but negatively to orange light and UVB. No obvious dodge activity was found among C. sinicus irradiated with <0.005 mW/cm^2 UV-B. Under 0.20, 0.30 and 0.50 mW/cm^2 UV-B radiation, the lethal half times of individuals were 30.47, 2.86, and 1.96 h, respectively. Grazing of C. sinicus was restrained at >0.10 mW/cm^2 UV-B, whereas yellow-red light stimulated grazing. Egg production rate was highest at a white-light intensity of 1.58 mW/cm^2, with an average rate of 10.04 eggs/(female·d). These results are consistent with the observed phenomenon that C. sinicus in the Yellow Sea mostly spawn near dawn. Our results indicate that light intensity and spectrum are important factors affecting the diel vertical migration of C. sinicus under natural conditions in the Yellow Sea.展开更多
This paper is devoted to analytical and numerical studies of global buckling of a sandwich circular plate. The mechanical properties of the plate core vary along its thickness, remaining constant in the facings. The m...This paper is devoted to analytical and numerical studies of global buckling of a sandwich circular plate. The mechanical properties of the plate core vary along its thickness, remaining constant in the facings. The middle surface of the plate is its symmetrical plane. The mathematical model of the plate is presented. The field of displacements is formulated using the proposed nonlinear hypothesis that generalizes the classical hypotheses. The equations of equilibrium are formulated based on the principle of stationary total potential energy. The proposed mathematical model of the displacements considers the shear effect. The numerical model of the plate is also formulated with a view to verify the analytical one. Numerical calculations are carried out for the chosen family of plates. The values of the critical load obtained by the analytical and numerical methods are compared. The effects of the material properties of the core and the change of the plate radius on the critical load intensity are presented.展开更多
Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used...Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model Stable Isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.展开更多
Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locat...Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locations of specific complexities, as the ones along unconventional hydrocarbon resources from the Brazilian pre-salt. The daily cost of well drilling under harsh conditions can exceed US $1 million a day, turning any type of downtime or necessary maintenance during the activities to be very costly, moment in which processes optimization starts to be a key factor in costs reduction. Thus, new technologies and methods in terms of automating and optimizing the processes may be of great advantages, having its impact in total related project costs. In this context, the goal of this research is to allow a computation tool supporting achieving a more efficient drilling process, by means of drilling mechanics parameters choosiness aiming rate of penetration (ROP) maximization and mechanic specific energy (MSE) minimization. Conceptually, driven by the pre-operational drilling test curve trends, the proposed system allows it to be performed with less human influences and being updateable automatically, allowing more precision and time reduction by selecting optimum parameters. A Web Operating System (Web OS) was designed and implemented, running in online servers, granting accessibility to it with any device that has a browser and internet connection. It allows processing the drilling parameters supplied and feed into it, issuing outcomes with optimum values in a faster and precise way, allowing reducing operating time.展开更多
This work proposes to design a fuzzy proportional-integral derivative (FPID) controller for dual-sensor cardiac pacemaker systems, which can automatically control the heart rate to accurately track a desired preset pr...This work proposes to design a fuzzy proportional-integral derivative (FPID) controller for dual-sensor cardiac pacemaker systems, which can automatically control the heart rate to accurately track a desired preset profile. The combination of fuzzy logic and conventional PID control approaches is adopted for the controller design based on dual-sensors. This controller offers good adaptation of the heart rate to the physiological needs of the patient under different states (rest and walk). Through comparing with the conventional fuzzy control algorithm, FPID provides a more suitable control strategy to determine a pacing rate in order to achieve a closer match between actual heart rate and a desired profile. To assist the heartbeat recovery, the stimuli with adjustable pacing rate is generated by the pacemaker according to the FPID controller, such actual heart rate may track the preset heart rate faithfully. Simulation results confirm that this proposed control design is effective for heartbeat recovery and maintenance. This study will be helpful not only for the analysis and treatment of bradycardias but also for improving the performance of medical devices.展开更多
The aim of the research work is to increase the yield of cotton fiber by improving the processing technology of germinated seeds, to improve the quality indicators of seeds and lint. In order to achieve this goal, a m...The aim of the research work is to increase the yield of cotton fiber by improving the processing technology of germinated seeds, to improve the quality indicators of seeds and lint. In order to achieve this goal, a mesh surface device was created to sort the seeds into fractions. Sorting technology was developed on this device and operating modes were determined. In addition, the law of surface distribution of the fractions separated from the cotton stream moving along the surface of the net was determined, and based on the results of practical and theoretical research, a mode of sorting of cotton seeds was developed. As a result, differential equations of the law of oscillation of seeds on parallel bases, taking into account the angle of inclination for the movement of cotton seeds on the sorting surface, were constructed and programmed on a computer to construct the trajectory of seeds. On the basis of the laws of motion, the optimal value of the angle of inclination on the horizontal, which gives the state of sorting of seeds, as well as the values of the amplitude and frequency of vibrations, was determined.展开更多
The use of the thermal power plant ashes including fly ash(FA) and bottom ash(BA) for producing unfired building bricks(UBB) using sodium hydroxide(NaOH) solution as an alkaline activator was investigated. A low appli...The use of the thermal power plant ashes including fly ash(FA) and bottom ash(BA) for producing unfired building bricks(UBB) using sodium hydroxide(NaOH) solution as an alkaline activator was investigated. A low applied forming pressure of 0.5 MPa and various NaOH concentrations of 5, 8, 10, and 12 M were used for the preparation of brick samples with different solution-to-binder(S/B) ratios of 0.35 and 0.40. The bricks were subjected to various test programs with reflecting the effect of both NaOH concentrations and S/B ratios on the brick’s properties. The compressive strength, unit weight, ultrasonic pulse velocity, and thermal conductivity of bricks increased with increasing NaOH concentration, whereas the contrary trend was found with increasing S/B ratio. Also, the water absorption of bricks was observed to reduce with increasing NaOH concentration and decreasing S/B ratio. As the results, the combined utilization of both low forming pressure and coal power plant ashes can produce the UBBs with low unit weight, low heat conductivity, and acceptable strength and water absorption rate as stipulated by TCVN 6477-2016. Furthermore, the outcomes of chemical analysis and microstructure observation also demonstrate that a high concentration of the Na OH promoted the geopolymerization process. Notably, the use of NaOH solution of either 10 M or above is recommended for the production of UBBs, which are classified as grade M5.0 or higher.展开更多
Diagnosing data or object detection in medical images is one of the important parts of image segmentation especially those data which is less effective to identify inMRI such as low-grade tumors or cerebral spinal flu...Diagnosing data or object detection in medical images is one of the important parts of image segmentation especially those data which is less effective to identify inMRI such as low-grade tumors or cerebral spinal fluid(CSF)leaks in the brain.The aim of the study is to address the problems associated with detecting the low-grade tumor and CSF in brain is difficult in magnetic resonance imaging(MRI)images and another problem also relates to efficiency and less execution time for segmentation of medical images.For tumor and CSF segmentation using trained light field database(LFD)datasets of MRI images.This research proposed the new framework of the hybrid k-Nearest Neighbors(k-NN)model that is a combination of hybridization of Graph Cut and Support Vector Machine(GCSVM)and Hidden Markov Model of k-Mean Clustering Algorithm(HMMkC).There are four different methods are used in this research namely(1)SVM,(2)GrabCut segmentation,(3)HMM,and(4)k-mean clustering algorithm.In this framework,on the one hand,phase one is to perform the classification of SVM and Graph Cut algorithm to create the maximum margin distance.This research use GrabCut segmentation method which is the application of the graph cut algorithm and extract the data with the help of scaleinvariant features transform.On the other hand,in phase two,segment the low-grade tumors and CSF using a method adapted for HMkC and extract the information of tumor or CSF fluid by GCHMkC including iterative conditional maximizing mode(ICMM)with identifying the range of distant.Comparative evaluation is also performing by the comparison of existing techniques in this research.In conclusion,our proposed model gives better results than existing.This proposed model helps to common man and doctor that can identify their condition of brain easily.In future,this will model will use for other brain related diseases.展开更多
A Colpitts oscillator, working around a 3 GHz frequency, contains a double gate Metal Oxide Semiconductor transistor (DGMOS). A mixed-mode analysis is involved, applying a quantum model to the device, whereas the rest...A Colpitts oscillator, working around a 3 GHz frequency, contains a double gate Metal Oxide Semiconductor transistor (DGMOS). A mixed-mode analysis is involved, applying a quantum model to the device, whereas the rest of the considered circuit is governed by Kirchhoff’s laws. The Linear Time Variant (LTV) model of phase noise is based on the Impulse Sensitivity Function of the Colpitts Oscillator which describes carefully the sensitivity of an oscillator to any impulse current injection in any node of the circuit. Finally, we improve the phase noise modeling, confronting some analytical developments to mixed-mode simulations.展开更多
Ge<sub>0.94</sub>Mn<sub>0.06</sub> nanocolumn thin film is a unique phase of GeMn diluted magnetic semiconductors (DMS) which exhibit Curie temperature (TC) > 400 K. The multilayers of Ge<...Ge<sub>0.94</sub>Mn<sub>0.06</sub> nanocolumn thin film is a unique phase of GeMn diluted magnetic semiconductors (DMS) which exhibit Curie temperature (TC) > 400 K. The multilayers of Ge<sub>0.94</sub>Mn<sub>0.06</sub> nanocolumns separated by nano-scaled spacers represent great interests for spintronic applications, such as spin valves or giant magneto-resistance (GMR) multilayers. In this article, we present the results obtained from the preliminary study on the exchange coupling in two types of GeMn nanocolumn/Ge multilayers. All the samples have been grown using molecular beam epitaxy (MBE). The superconducting quantum interference device (SQUID) magnetometer has been used to determine the magnetic properties of the samples. In the multilayer system Ge/[Ge<sub>0.94</sub>Mn<sub>0.06</sub>(40 nm)/Ge(d nm)]9/Ge<sub>0.94</sub>Mn<sub>0.06</sub>(40 nm)/Ge, no exchange coupling can be observed. Inversely, exchange coupling between the layers exists and depends on the thickness of the Ge spacers for the GeMn nanocolumns/Ge multilayer spin valve systems. The exchange coupling in the nanocolumns multilayer systems has been shown to be complex due to the leakage field induced by neighboring nanocolumns and the magnetic anisotropy of nanocolumns.展开更多
There is widespread and strong interest in trying to fabricate a metamaterial in which both the permittivity and permeability are equal to -1 in order to achieve sub-wavelength imaging. Several metamaterial constructs...There is widespread and strong interest in trying to fabricate a metamaterial in which both the permittivity and permeability are equal to -1 in order to achieve sub-wavelength imaging. Several metamaterial constructs have been proposed with varying degrees of success because of inherent losses, limited bandwidth and scattering from the abstracted circuit elements constituting the artificial material itself. A further limitation is the need to capture evanescent components from the object to be imaged that requires the lens to be located near the object. We have studied the underlying models and constraints that influence the design of a negative index lens and present this analysis as well as reviewing the opportunities. There are inevitable and well-known trade-offs between lens thickness, wavelength, dispersion and absorption. However, these can be characterized both numerically and experimentally, suggesting that a computational imaging approach to the recovery of sub-wavelength features might be effective. Depending on the specific details of the metamaterial employed for imaging, one can consider the data acquired to represent a set of coded apertures.展开更多
Several recent business reports have described the global growth in demand for optical and photonic components,paralleled by technical reports on the growing shortage of skilled manufacturing staff to meet this demand...Several recent business reports have described the global growth in demand for optical and photonic components,paralleled by technical reports on the growing shortage of skilled manufacturing staff to meet this demand.It is remarkable that producing ultraprecision surfaces remains so dependent on people,in contrast to other sectors of the economy,e.g.,car manufacturing.Clearly,training can play some role,but ultimately,only process automation can provide the solution.This paper explores why automation is a challenge and summarizes multidisciplinary work aiming to assemble the building blocks required to realize automation.展开更多
Nitrogen-rich graphitized carbon microspheres(NGCs)with hierarchically porous were constructed by self-assembly.Under different heat treatment conditions,the structure,morphology and properties of NGCs were studied by...Nitrogen-rich graphitized carbon microspheres(NGCs)with hierarchically porous were constructed by self-assembly.Under different heat treatment conditions,the structure,morphology and properties of NGCs were studied by using multiple characterization techniques.The results showed that the chemical microenvironments(e.g.surface chemistry,degree of graphitization and defective,etc.)and microstructures properties(e.g.morphology,specific surface area,particle size,etc.)could be delicately controlled via thermal carbonization processes.The degradation of ofloxacin(OFLX)by NGCs activated peroxymonosulfate(PMS)was studied systematically.It was found that the synergistic coupling effect between optimum N or O bonding species configuration ratio(graphitic N and C=O)and special microstructure was the main reason for the enhanced catalytic activity of NGC-800(calcination temperature at 800°C).Electron paramagnetic resonance(EPR)experiments and radical quenching experiments indicated that the hydroxyl(·OH),sulfate(SO4^·-)and singlet oxygen(^1O_(2))were contributors in the NGC-800/PMS systems.Further investigation of the durability of chemical structures and surface active sites revealed that undergo N bonding species configuration reconstruction and cannibalistic oxidation during PMS activation reaction.The used NGC-800 physicochemical properties could be recovered by heat treatment to achieve the ideal catalytic performance.The findings proposed a valuable insight for catalytic performance and controllable design of construction.展开更多
Low salinity water is an emerging enhanced oil recovery(EOR)method that causes wettability alteration towards a favorable state to reduce residual oil saturation,while water alternating gas(WAG)is a proven EOR process...Low salinity water is an emerging enhanced oil recovery(EOR)method that causes wettability alteration towards a favorable state to reduce residual oil saturation,while water alternating gas(WAG)is a proven EOR process that enhances oil recovery by controlling mobility of both water and gas.Therefore,combining the two EOR processes as low salinity water-alternating CO2 EOR injection(LSWA CO2)can further improve oil recovery by promoting the synergy of the mechanisms underlying these two methods.Core flooding experiments,contact angle,interfacial tension(IFT),and CO2 solubility measurement in oil and brine were conducted to investigate the viability and performance of LSWA CO2 in sandstone reservoirs.A favorable wettability alteration,along with IFT reduction and mobility control,are the mechanisms that contribute to residual oil mobilization efficiencies during the LSWA CO2 EOR process.In addition,LSWA CO2 core flooding experiments result in a significant incremental oil recovery.Three smart waters were tested in our research,to examine the impact of changing cationic composition on oil recovery.The solutions are designed brines as NaCl(SW1),MgCl2(SW2),and KCl(SW3).Of the three solutions,SW1 yields the highest incremental oil recovery and highest IFT reduction.In addition,it results in a favorable wettability alteration towards a more water-wet state.In all cases,introducing CO2 to the brine/oil system shows a great advantage in terms of enhancing wettability modification,promoting IFT reduction,and controlling the displacement front of the injected fluid through mobility control.展开更多
基金Supported by the National Key R&D Program of China(No.2017YFC1404402)the Science&Technology Basic Resources Investigation Program of China(No.2017FY100803)+1 种基金the Project of Global Change and Air-Sea Interaction(No.GASI-02-PAC-STMSspr)the National Natural Science Foundation of China(No.41306155)
文摘The effects of wavelength-specific visible light, white light, and ultraviolet-B (UV-B, 280- 315 nm) on selected behaviors, grazing rate, spawning rate, and hatching rate of the marine copepod Calanus sinicus collected from the Yellow Sea were studied. Calanus sinicus placed in a partitioned experimental system responded positively phototaxis to blue-cyan and yellow light but negatively to orange light and UVB. No obvious dodge activity was found among C. sinicus irradiated with <0.005 mW/cm^2 UV-B. Under 0.20, 0.30 and 0.50 mW/cm^2 UV-B radiation, the lethal half times of individuals were 30.47, 2.86, and 1.96 h, respectively. Grazing of C. sinicus was restrained at >0.10 mW/cm^2 UV-B, whereas yellow-red light stimulated grazing. Egg production rate was highest at a white-light intensity of 1.58 mW/cm^2, with an average rate of 10.04 eggs/(female·d). These results are consistent with the observed phenomenon that C. sinicus in the Yellow Sea mostly spawn near dawn. Our results indicate that light intensity and spectrum are important factors affecting the diel vertical migration of C. sinicus under natural conditions in the Yellow Sea.
文摘This paper is devoted to analytical and numerical studies of global buckling of a sandwich circular plate. The mechanical properties of the plate core vary along its thickness, remaining constant in the facings. The middle surface of the plate is its symmetrical plane. The mathematical model of the plate is presented. The field of displacements is formulated using the proposed nonlinear hypothesis that generalizes the classical hypotheses. The equations of equilibrium are formulated based on the principle of stationary total potential energy. The proposed mathematical model of the displacements considers the shear effect. The numerical model of the plate is also formulated with a view to verify the analytical one. Numerical calculations are carried out for the chosen family of plates. The values of the critical load obtained by the analytical and numerical methods are compared. The effects of the material properties of the core and the change of the plate radius on the critical load intensity are presented.
基金Supported by the National Key Research and Development Program of China(Nos.2017YFC1404401,2017YFC1404402)the National Natural Science Foundation of China(No.41706189)。
文摘Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model Stable Isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.
文摘Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locations of specific complexities, as the ones along unconventional hydrocarbon resources from the Brazilian pre-salt. The daily cost of well drilling under harsh conditions can exceed US $1 million a day, turning any type of downtime or necessary maintenance during the activities to be very costly, moment in which processes optimization starts to be a key factor in costs reduction. Thus, new technologies and methods in terms of automating and optimizing the processes may be of great advantages, having its impact in total related project costs. In this context, the goal of this research is to allow a computation tool supporting achieving a more efficient drilling process, by means of drilling mechanics parameters choosiness aiming rate of penetration (ROP) maximization and mechanic specific energy (MSE) minimization. Conceptually, driven by the pre-operational drilling test curve trends, the proposed system allows it to be performed with less human influences and being updateable automatically, allowing more precision and time reduction by selecting optimum parameters. A Web Operating System (Web OS) was designed and implemented, running in online servers, granting accessibility to it with any device that has a browser and internet connection. It allows processing the drilling parameters supplied and feed into it, issuing outcomes with optimum values in a faster and precise way, allowing reducing operating time.
文摘This work proposes to design a fuzzy proportional-integral derivative (FPID) controller for dual-sensor cardiac pacemaker systems, which can automatically control the heart rate to accurately track a desired preset profile. The combination of fuzzy logic and conventional PID control approaches is adopted for the controller design based on dual-sensors. This controller offers good adaptation of the heart rate to the physiological needs of the patient under different states (rest and walk). Through comparing with the conventional fuzzy control algorithm, FPID provides a more suitable control strategy to determine a pacing rate in order to achieve a closer match between actual heart rate and a desired profile. To assist the heartbeat recovery, the stimuli with adjustable pacing rate is generated by the pacemaker according to the FPID controller, such actual heart rate may track the preset heart rate faithfully. Simulation results confirm that this proposed control design is effective for heartbeat recovery and maintenance. This study will be helpful not only for the analysis and treatment of bradycardias but also for improving the performance of medical devices.
文摘The aim of the research work is to increase the yield of cotton fiber by improving the processing technology of germinated seeds, to improve the quality indicators of seeds and lint. In order to achieve this goal, a mesh surface device was created to sort the seeds into fractions. Sorting technology was developed on this device and operating modes were determined. In addition, the law of surface distribution of the fractions separated from the cotton stream moving along the surface of the net was determined, and based on the results of practical and theoretical research, a mode of sorting of cotton seeds was developed. As a result, differential equations of the law of oscillation of seeds on parallel bases, taking into account the angle of inclination for the movement of cotton seeds on the sorting surface, were constructed and programmed on a computer to construct the trajectory of seeds. On the basis of the laws of motion, the optimal value of the angle of inclination on the horizontal, which gives the state of sorting of seeds, as well as the values of the amplitude and frequency of vibrations, was determined.
文摘The use of the thermal power plant ashes including fly ash(FA) and bottom ash(BA) for producing unfired building bricks(UBB) using sodium hydroxide(NaOH) solution as an alkaline activator was investigated. A low applied forming pressure of 0.5 MPa and various NaOH concentrations of 5, 8, 10, and 12 M were used for the preparation of brick samples with different solution-to-binder(S/B) ratios of 0.35 and 0.40. The bricks were subjected to various test programs with reflecting the effect of both NaOH concentrations and S/B ratios on the brick’s properties. The compressive strength, unit weight, ultrasonic pulse velocity, and thermal conductivity of bricks increased with increasing NaOH concentration, whereas the contrary trend was found with increasing S/B ratio. Also, the water absorption of bricks was observed to reduce with increasing NaOH concentration and decreasing S/B ratio. As the results, the combined utilization of both low forming pressure and coal power plant ashes can produce the UBBs with low unit weight, low heat conductivity, and acceptable strength and water absorption rate as stipulated by TCVN 6477-2016. Furthermore, the outcomes of chemical analysis and microstructure observation also demonstrate that a high concentration of the Na OH promoted the geopolymerization process. Notably, the use of NaOH solution of either 10 M or above is recommended for the production of UBBs, which are classified as grade M5.0 or higher.
基金the Universiti Teknikal Malaysia Melaka (UTeM)the Ministry of Education, Malaysia for being financial sponsorsUniversiti Kebangsaan Malaysia (UKM) for the financial support under research grants GUP-2012-040 and AP-2012-014
文摘Diagnosing data or object detection in medical images is one of the important parts of image segmentation especially those data which is less effective to identify inMRI such as low-grade tumors or cerebral spinal fluid(CSF)leaks in the brain.The aim of the study is to address the problems associated with detecting the low-grade tumor and CSF in brain is difficult in magnetic resonance imaging(MRI)images and another problem also relates to efficiency and less execution time for segmentation of medical images.For tumor and CSF segmentation using trained light field database(LFD)datasets of MRI images.This research proposed the new framework of the hybrid k-Nearest Neighbors(k-NN)model that is a combination of hybridization of Graph Cut and Support Vector Machine(GCSVM)and Hidden Markov Model of k-Mean Clustering Algorithm(HMMkC).There are four different methods are used in this research namely(1)SVM,(2)GrabCut segmentation,(3)HMM,and(4)k-mean clustering algorithm.In this framework,on the one hand,phase one is to perform the classification of SVM and Graph Cut algorithm to create the maximum margin distance.This research use GrabCut segmentation method which is the application of the graph cut algorithm and extract the data with the help of scaleinvariant features transform.On the other hand,in phase two,segment the low-grade tumors and CSF using a method adapted for HMkC and extract the information of tumor or CSF fluid by GCHMkC including iterative conditional maximizing mode(ICMM)with identifying the range of distant.Comparative evaluation is also performing by the comparison of existing techniques in this research.In conclusion,our proposed model gives better results than existing.This proposed model helps to common man and doctor that can identify their condition of brain easily.In future,this will model will use for other brain related diseases.
文摘A Colpitts oscillator, working around a 3 GHz frequency, contains a double gate Metal Oxide Semiconductor transistor (DGMOS). A mixed-mode analysis is involved, applying a quantum model to the device, whereas the rest of the considered circuit is governed by Kirchhoff’s laws. The Linear Time Variant (LTV) model of phase noise is based on the Impulse Sensitivity Function of the Colpitts Oscillator which describes carefully the sensitivity of an oscillator to any impulse current injection in any node of the circuit. Finally, we improve the phase noise modeling, confronting some analytical developments to mixed-mode simulations.
文摘Ge<sub>0.94</sub>Mn<sub>0.06</sub> nanocolumn thin film is a unique phase of GeMn diluted magnetic semiconductors (DMS) which exhibit Curie temperature (TC) > 400 K. The multilayers of Ge<sub>0.94</sub>Mn<sub>0.06</sub> nanocolumns separated by nano-scaled spacers represent great interests for spintronic applications, such as spin valves or giant magneto-resistance (GMR) multilayers. In this article, we present the results obtained from the preliminary study on the exchange coupling in two types of GeMn nanocolumn/Ge multilayers. All the samples have been grown using molecular beam epitaxy (MBE). The superconducting quantum interference device (SQUID) magnetometer has been used to determine the magnetic properties of the samples. In the multilayer system Ge/[Ge<sub>0.94</sub>Mn<sub>0.06</sub>(40 nm)/Ge(d nm)]9/Ge<sub>0.94</sub>Mn<sub>0.06</sub>(40 nm)/Ge, no exchange coupling can be observed. Inversely, exchange coupling between the layers exists and depends on the thickness of the Ge spacers for the GeMn nanocolumns/Ge multilayer spin valve systems. The exchange coupling in the nanocolumns multilayer systems has been shown to be complex due to the leakage field induced by neighboring nanocolumns and the magnetic anisotropy of nanocolumns.
文摘There is widespread and strong interest in trying to fabricate a metamaterial in which both the permittivity and permeability are equal to -1 in order to achieve sub-wavelength imaging. Several metamaterial constructs have been proposed with varying degrees of success because of inherent losses, limited bandwidth and scattering from the abstracted circuit elements constituting the artificial material itself. A further limitation is the need to capture evanescent components from the object to be imaged that requires the lens to be located near the object. We have studied the underlying models and constraints that influence the design of a negative index lens and present this analysis as well as reviewing the opportunities. There are inevitable and well-known trade-offs between lens thickness, wavelength, dispersion and absorption. However, these can be characterized both numerically and experimentally, suggesting that a computational imaging approach to the recovery of sub-wavelength features might be effective. Depending on the specific details of the metamaterial employed for imaging, one can consider the data acquired to represent a set of coded apertures.
基金Funding was provided by Engineering and Physical Sciences Research Council(Grant Nos.EP/V029304/1,EP/V029274/1,EP/V029266/1,EP/V029401/1)Innovate UK(Grant No.10029272).
文摘Several recent business reports have described the global growth in demand for optical and photonic components,paralleled by technical reports on the growing shortage of skilled manufacturing staff to meet this demand.It is remarkable that producing ultraprecision surfaces remains so dependent on people,in contrast to other sectors of the economy,e.g.,car manufacturing.Clearly,training can play some role,but ultimately,only process automation can provide the solution.This paper explores why automation is a challenge and summarizes multidisciplinary work aiming to assemble the building blocks required to realize automation.
基金the National Natural Science Foundation of China(No.51578295)the National Natural Science Foundation of Jiangsu Province(No.BK20161479)+3 种基金Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse(Nanjing University of Science and Technology)Qinglan Project of Jiangsu Province supported this studyFoundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materialsa project funded by the priority academic program development of Jiangsu Higher Education Institutions。
文摘Nitrogen-rich graphitized carbon microspheres(NGCs)with hierarchically porous were constructed by self-assembly.Under different heat treatment conditions,the structure,morphology and properties of NGCs were studied by using multiple characterization techniques.The results showed that the chemical microenvironments(e.g.surface chemistry,degree of graphitization and defective,etc.)and microstructures properties(e.g.morphology,specific surface area,particle size,etc.)could be delicately controlled via thermal carbonization processes.The degradation of ofloxacin(OFLX)by NGCs activated peroxymonosulfate(PMS)was studied systematically.It was found that the synergistic coupling effect between optimum N or O bonding species configuration ratio(graphitic N and C=O)and special microstructure was the main reason for the enhanced catalytic activity of NGC-800(calcination temperature at 800°C).Electron paramagnetic resonance(EPR)experiments and radical quenching experiments indicated that the hydroxyl(·OH),sulfate(SO4^·-)and singlet oxygen(^1O_(2))were contributors in the NGC-800/PMS systems.Further investigation of the durability of chemical structures and surface active sites revealed that undergo N bonding species configuration reconstruction and cannibalistic oxidation during PMS activation reaction.The used NGC-800 physicochemical properties could be recovered by heat treatment to achieve the ideal catalytic performance.The findings proposed a valuable insight for catalytic performance and controllable design of construction.
文摘Low salinity water is an emerging enhanced oil recovery(EOR)method that causes wettability alteration towards a favorable state to reduce residual oil saturation,while water alternating gas(WAG)is a proven EOR process that enhances oil recovery by controlling mobility of both water and gas.Therefore,combining the two EOR processes as low salinity water-alternating CO2 EOR injection(LSWA CO2)can further improve oil recovery by promoting the synergy of the mechanisms underlying these two methods.Core flooding experiments,contact angle,interfacial tension(IFT),and CO2 solubility measurement in oil and brine were conducted to investigate the viability and performance of LSWA CO2 in sandstone reservoirs.A favorable wettability alteration,along with IFT reduction and mobility control,are the mechanisms that contribute to residual oil mobilization efficiencies during the LSWA CO2 EOR process.In addition,LSWA CO2 core flooding experiments result in a significant incremental oil recovery.Three smart waters were tested in our research,to examine the impact of changing cationic composition on oil recovery.The solutions are designed brines as NaCl(SW1),MgCl2(SW2),and KCl(SW3).Of the three solutions,SW1 yields the highest incremental oil recovery and highest IFT reduction.In addition,it results in a favorable wettability alteration towards a more water-wet state.In all cases,introducing CO2 to the brine/oil system shows a great advantage in terms of enhancing wettability modification,promoting IFT reduction,and controlling the displacement front of the injected fluid through mobility control.