This paper explores the deformation mechanism and control technology of roof pre-splitting for gob-side entries in hard roof full-mechanized longwall caving panel(LTCC).The investigation utilizes a comprehensive appro...This paper explores the deformation mechanism and control technology of roof pre-splitting for gob-side entries in hard roof full-mechanized longwall caving panel(LTCC).The investigation utilizes a comprehensive approach that integrates field monitoring,theoretical analysis,and numerical simulation.Theoretical analysis has illuminated the influence of the length of the lateral cantilever beam of the main roof(LCBM)above the roadway on the stability of the gob-side entry behind the panel.Numerical simulations have further revealed that the longer LCBM results in heightened vertical stress within the coal pillar,developed cracks around the roadway,and more pronounced damage to the roadway.Moreover,numerical simulations also demonstrate the potential of roof pre-splitting technology in optimizing the fracture position of the hard roof.This technology significantly reduces the length of the LCBM,thereby alleviating stress concentration in the coal pillars and integrated coal rib while minimizing the destruction of the gob-side entry.Therefore,this manuscript first proposes the use of roof pre-splitting technology to control roadway deformation,and automatically retain the entry within a hard roof LTCC panel.Field implementation has demonstrated that the proposed automatically retained entry by roof pre-splitting technology effectively reduces gob-side entry deformation and achieves automatically retained entry.展开更多
Soybean diseases and insect pests are important factors that affect the output and quality of the soybean,thus,it is necessary to do correct inspection and diagnosis on them.For this reason,based on improved transfer ...Soybean diseases and insect pests are important factors that affect the output and quality of the soybean,thus,it is necessary to do correct inspection and diagnosis on them.For this reason,based on improved transfer learning,a classification method of the soybean leaf diseases was proposed in this paper.In detail,this method first removed the complicated background in images and cut apart leaves from the entire image;second,the data-augmented method was applied to amplify the separated leaf disease image dataset to reduce overfitting;at last,the automatically fine-tuning convolutional neural network(AutoTun)was adopted to classify the soybean leaf diseases.The proposed method respectively reached 94.23%,93.51%and 94.91%of validation accuracy rates on VGG-16,ResNet-34 and DenseNet-121,and it was compared with the traditional fine-tuning method of transfer learning.The results indicated that the proposed method had superior to the traditional transfer learning method.展开更多
Platycodon grandiflorum A.DC.(PAl)C)root was taken as experiment material to extract polysaccharide.On the base of single factor tests(extraction time,extraction temperature,liquid-solid ratio,solvent pH value and NaC...Platycodon grandiflorum A.DC.(PAl)C)root was taken as experiment material to extract polysaccharide.On the base of single factor tests(extraction time,extraction temperature,liquid-solid ratio,solvent pH value and NaCl concentration),the study concluded the main factors affecting the extraction of PADC polysaccharide,which are liquid-solid ratio,extraction time and extraction temperature.Then through central-composite test design,the extraction conditions were concluded as liquid-solid ratio 34.43,extraction time 89.83 min and extraction temperature 52.47℃.By means of validation experiments,the adequacy of this model was confirmed.展开更多
Because of the limitations of electric vehicle(EV)battery technology and relevant supporting facilities,there is a great risk of breakdown of EVs during driving.The resulting driver“range anxiety”greatly affects the...Because of the limitations of electric vehicle(EV)battery technology and relevant supporting facilities,there is a great risk of breakdown of EVs during driving.The resulting driver“range anxiety”greatly affects the travel quality of EVs.These limitations should be overcome to promote the use of EVs.In this study,a method for travel path planning considering EV power supply was developed.First,based on real-time road conditions,a dynamic energy model of EVs was established considering the driving energy and accessory energy.Second,a multi-objective travel path planning model of EVs was constructed considering the power supply,taking the distance,time,energy,and charging cost as the optimization objectives.Finally,taking the actual traffic network of 15 km×15 km area in a city as the research object,the model was simulated and verified in MATLAB based on Dijkstra shortest path algorithm.The simulation results show that compared with the traditional route planning method,the total distance in the proposed optimal route planning method increased by 1.18%,but the energy consumption,charging cost,and driving time decreased by 11.62%,41.26%and 11.00%,respectively,thus effectively reducing the travel cost of EVs and improving the driving quality of EVs.展开更多
High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synth...High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synthetic high salinity wastewater was evaluated at laboratory scale during a 110-day operation.The reactor was operated in a 12 h cycle,and each cycle consisted of 0.25 h influent addition,8 h aeration,3 h anoxic reaction,0.5 h sedimentation and 0.25 h effluent withdrawal.Gradual increase in salinity gradient was applied during the acclimatization period.The acclimated SBBR system was demonstrated to be an effective process to remove organic compounds and ammonia nitrogen under high salinity conditions with chemical oxygen demand(COD)and ammonia nitrogen(NH3-N)removal efficiencies of 88% and 80%,respectively.The microscopic examination indicated that rather than rotifers or vorticella,the zoogloea,filamentous fungus mingled with a small quantity of swimming infusorians were dominant bacteria in SBBR system.The removal efficiencies close to 80% in COD and 75% in NH3-N were achieved at an organic loading rate(OLR)of 0.96 kg COD/(m3·d),pH of 7.0,salinity of 14 g/L and NH3-N of 30 mg/L.展开更多
This work aims to establish a suitable numerical simulation model for hybrid laser-electric arc heat source welding of dissimilar Mg alloys between AZ31 and AZ80. Based on the energy conservation law and Fourier’s la...This work aims to establish a suitable numerical simulation model for hybrid laser-electric arc heat source welding of dissimilar Mg alloys between AZ31 and AZ80. Based on the energy conservation law and Fourier’s law of heat conduction, the differential equations of the three-dimensional temperature field for nonlinear transient heat conduction are built. According to the analysis of nonlinear transient heat transfer, the equations representing initial conditions and boundary conditions are obtained. The “double ellipsoidal heat source + 3D Gaussian heat source”combination was chosen to construct the laser-electric arc hybrid heat source. The weld bead morphologies and the distribution of temperature, stress, displacement and plastic strains are numerically simulated. The actual welding experiments were performed by a hybrid laser-electric arc welding machine. The interaction mechanism between laser and electric arc in the hybrid welding of Mg alloys is discussed in detail. The hybrid heat source can promote the absorption of laser energy and electric arc in the molten pool, resulting in more uniform energy distribution in the molten pool and the corresponding improvement of welding parameters. This work can provide theoretical guidance and data supports for the optimization of the hybrid laser-electric arc welding processes for Mg alloys.展开更多
By employing function one-direction S-rough sets and rough law generation method based on function S-rough sets, ^-f-decomposition law and ^-F-decomposition rough law are proposed, and the measurement of rough law var...By employing function one-direction S-rough sets and rough law generation method based on function S-rough sets, ^-f-decomposition law and ^-F-decomposition rough law are proposed, and the measurement of rough law variation in the process of rough law ^-F-decomposition is researched. The concepts of law energy and attdbute ^-f-interference degree are presented, which make the variation of rough law become measurable. ^-f-decomposition law energy characteristic theorem, ^-f- decomposition law energy inequality theorem, ^-F-decomposition rough law energy characteristic theorem, and ^-f-decomposition law energy mean value theorem are presented.展开更多
Cation ion-exchange resin particles （CERP）/polyethersulfone （PES） hybrid catalytic membranes were prepared by immerse phase inversion for the esterification of different free fatty acids （FFAs） （such as, dodeca...Cation ion-exchange resin particles （CERP）/polyethersulfone （PES） hybrid catalytic membranes were prepared by immerse phase inversion for the esterification of different free fatty acids （FFAs） （such as, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and octadecadienoic acid） with methanol. The membranes were characterized by SEM, ion-exchange capacity and swelling degree test. It is found that dodecanoic acid has the highest FFAs conversion among the four acids for its stronger acidic and reactivity. Different effects of membrane annealing temperature, reaction temperature, molar ratio of methanol to FFAs and catalytic membrane loading on the esterification were investigated by the esterification of dodecanoic acid with methanol. The dodecanoic acid conversion reaches 97.5% trader the optimal condition when the esterification reaction lasted for 8 h.展开更多
Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensi...Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.展开更多
Graphite nanoplatelets were prepared by a novel magnetic-grinding method using self-made equipments. Under a variant magnetic field, magnetic needles collided at a high rotating speed and exfoliated pristine graphite ...Graphite nanoplatelets were prepared by a novel magnetic-grinding method using self-made equipments. Under a variant magnetic field, magnetic needles collided at a high rotating speed and exfoliated pristine graphite into graphite nanoplatelets with high efficiency. The obtained graphite nanoplatelets are highly crystalline, and the thickness is less than 10 nm. Moreover, the surface area could reached 738.1 m^2/g with a grinding time of 4 h. Silanized graphite nanoplatelets can disperse well in SG 15W-40 engine oil and serve as lubricant additive. Tribological results indicate that the friction coefficient and wear-scar of the friction pairs are lower than 76% and 41%, respectively, by adding 1.5‰(mass fraction) of silanized graphite nanoplatelets. Notably, the functionalized graphite nanoplatelets can realize large-scale production and commercial application.展开更多
The grain size, textures and grain boundary plane distributions in a cold-rolled and annealed ferritic stainless steel were investigated by means of EBSD techniques. The results show that, following cold rolling with ...The grain size, textures and grain boundary plane distributions in a cold-rolled and annealed ferritic stainless steel were investigated by means of EBSD techniques. The results show that, following cold rolling with the thickness reduction of 85%, relatively low temperature （780℃） annealing brings an extremely sluggish grain growth and no grain texture develops when the annealing time varies from 5 min to 480 min. The free energy reduction of the system is mainly caused by the grain boundary plane re-orientation in addition to minor grain growth because the distributions of grain boundary planes are moderately preferred on { 100} according to the five parameter analyses （FPA） concerning the grain boundary plane characteristics. However, in the case of high-temperature （1 000 ℃） annealing, the average grain size does not increase until annealing time is prolonged to 90 min, after which extensive grain growth occurs and strong {100}（hkl） texture emerges whereas nearly random grain boundary plane distributions are observed. The free energy reduction of the system is most likely attributed to the selective growth.展开更多
Land use and protection has become a global hot spot.How to use land resources is an important topic for the future socio-economic sustainable development.This paper analyzes the land use changes of Mata lake of Shand...Land use and protection has become a global hot spot.How to use land resources is an important topic for the future socio-economic sustainable development.This paper analyzes the land use changes of Mata lake of Shandong province in China,from 1985's to 2000's using multi-temporal remotely sensed data including TM in the 1985s,ETM+in the 2000s and ancillary data such as soil use map,water map etc.The remote sensing imageries were calibrated,registered and geo-referenced,then classified by multi-source information data and remote sensing image interpretation expert system based on knowledge base.Five land use types were extracted from remote sensing imageries,that is,water body,agriculture land,rural settlement,bare land and none-use land.The total precision is 80.7% and Kappa index is 0.825.The analysis result of the remote sensing shows that during the past 15 years,water resource dropped off very promptly from 51.77 km2 to 16.65 km2 and bare land reduced greatly more than 60% in Mata lake region.With the development of the economy and agriculture areas,more and more water body and bare land converted to agriculture land use and rural settlement areas.Since last years,the Mata lake has been affected by natural factor,human activity and increasing population.So its land use pattern greatly changed from 1985 to 2000.The information of land use changes provided scientific supports for land planning and environmental protection.展开更多
Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coal...Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.展开更多
Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samp...Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samples with different somatic cell counts were collected and preprocessing methods were studied.Variable selection algorithm based on hybrid strategy and modelling method based on ensemble learning were explored for somatic cell count detection.Detection model was used to diagnose subclinical mastitis and the results showed that near-infrared spectroscopy could be a tool to realize rapid detection of somatic cell count in milk.展开更多
To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conduct...To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.展开更多
In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method wa...In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method was utilized to prepare Nb_(4)AlC_(3)nanosheets,and then a piece of tapered fiber was adopted to fabricate Nb_(4)AlC_(3)-SA.It was found that the saturation intensity and modulation depth of the Nb_(4)AlC_(3)-SA are 2.02 MW/cm^(2)and 1.88%.Based on the Nb_(4)AlC_(3)-SA,a conventional soliton(CS)mode-locked EDF laser was achieved.The central wavelength,pulse duration,and pulse repetition rate were found to be 1565.65 nm,615.37 fs,and 24.63 MHz,respectively.The performance is competitive and particularly superior in terms of pulse duration.This study fully confirms that Nb_(4)AlC_(3)possesses marvellous nonlinear saturable absorption properties and opens new possibilities for further research on air-stable ultrafast photon-ic devices.展开更多
To address the challenges of low detection accuracy caused by the diverse species,significant size variations,and complex growth environments of wheat pests in natural settings,a PSA-YOLO11n algorithm is proposed to e...To address the challenges of low detection accuracy caused by the diverse species,significant size variations,and complex growth environments of wheat pests in natural settings,a PSA-YOLO11n algorithm is proposed to enhance detection precision.Building upon the YOLO11n framework,the proposed improvements include three key components:1)SimCSPSPPF in Backbone:An improved Spatial Pyramid Pooling-Fast(SPPF)module,SimCSPSPPF,is integrated into the Backbone to reduce the number of channels in the hidden layers,thereby accelerating model training.2)PEC in Neck:The standard convolution layers in the Neck are replaced with Perception Enhancement Convolutions(PEC)to improve multi-scale feature extraction capabilities,enhancing detection speed.3)AWIoU Loss Function:The regression loss function is replaced with Adequate Wise IoU(AWIoU),addressing issues of bounding box distortion caused by the diversity in pest species and size variations,thereby improving the precision of bounding box localization.Experimental evaluations on the IP102 dataset demonstrate that PSA-YOLO11n achieves a mean Average Precision(mAP)of 89.10%,surpassing YOLO11n by 0.8%.Comparisons with other mainstream algorithms,including Faster R-CNN,RetinaNet,YOLOv5s,YOLOv8n,YOLOv10n,and YOLO11n,confirm that PSA-YOLO11n outperforms all baselines in terms of detection performance.These results highlight the algorithm’s capability to significantly improve the detection accuracy of multi-scale wheat pests in natural environments,providing an effective solution for pest management in wheat production.展开更多
基金Project(52104139)supported by the National Natural Science Foundation of China Youth Science FoundationProject(SKLGDUEK2132)supported by the State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology/China University of Mining and Technology-BeijingProjects([2020]2Y030,[2020]2Y019,[2020j3007,[2020]3008,and[2022j0il]supported by the Guizhou Province Science and Technology Planning,China Project(2022B01051)supported by the Key Research and Development Special Tasks of Xinjiang,China。
文摘This paper explores the deformation mechanism and control technology of roof pre-splitting for gob-side entries in hard roof full-mechanized longwall caving panel(LTCC).The investigation utilizes a comprehensive approach that integrates field monitoring,theoretical analysis,and numerical simulation.Theoretical analysis has illuminated the influence of the length of the lateral cantilever beam of the main roof(LCBM)above the roadway on the stability of the gob-side entry behind the panel.Numerical simulations have further revealed that the longer LCBM results in heightened vertical stress within the coal pillar,developed cracks around the roadway,and more pronounced damage to the roadway.Moreover,numerical simulations also demonstrate the potential of roof pre-splitting technology in optimizing the fracture position of the hard roof.This technology significantly reduces the length of the LCBM,thereby alleviating stress concentration in the coal pillars and integrated coal rib while minimizing the destruction of the gob-side entry.Therefore,this manuscript first proposes the use of roof pre-splitting technology to control roadway deformation,and automatically retain the entry within a hard roof LTCC panel.Field implementation has demonstrated that the proposed automatically retained entry by roof pre-splitting technology effectively reduces gob-side entry deformation and achieves automatically retained entry.
基金Supported by the National Science Fund for Distinguished Young Scholars(31902210)Heilongjiang Province University Youth Innovative Talent Training Program Project(UNPYSCT-2018142)+2 种基金Heilongjiang Provincial Natural Science Foundation of China(QC2018074)"Young Talents"Project of NEAU Scholars Program(18QC23)Open Project of Key Laboratory of Agricultural Internet of Things,Ministry of Agriculture and Rural Affairs(2018AIOT-02)。
文摘Soybean diseases and insect pests are important factors that affect the output and quality of the soybean,thus,it is necessary to do correct inspection and diagnosis on them.For this reason,based on improved transfer learning,a classification method of the soybean leaf diseases was proposed in this paper.In detail,this method first removed the complicated background in images and cut apart leaves from the entire image;second,the data-augmented method was applied to amplify the separated leaf disease image dataset to reduce overfitting;at last,the automatically fine-tuning convolutional neural network(AutoTun)was adopted to classify the soybean leaf diseases.The proposed method respectively reached 94.23%,93.51%and 94.91%of validation accuracy rates on VGG-16,ResNet-34 and DenseNet-121,and it was compared with the traditional fine-tuning method of transfer learning.The results indicated that the proposed method had superior to the traditional transfer learning method.
文摘Platycodon grandiflorum A.DC.(PAl)C)root was taken as experiment material to extract polysaccharide.On the base of single factor tests(extraction time,extraction temperature,liquid-solid ratio,solvent pH value and NaCl concentration),the study concluded the main factors affecting the extraction of PADC polysaccharide,which are liquid-solid ratio,extraction time and extraction temperature.Then through central-composite test design,the extraction conditions were concluded as liquid-solid ratio 34.43,extraction time 89.83 min and extraction temperature 52.47℃.By means of validation experiments,the adequacy of this model was confirmed.
基金Projects(51908388,51508315,51905320)supported by the National Natural Science Foundation of ChinaProject(2019 JZZY 010911)supported by the Key R&D Program of Shandong Province,China+1 种基金Project supported by the Shandong University of Technology&Zibo City Integration Develo pment Project,ChinaProject(ZR 2021 MG 012)supported by Shandong Provincial Natural Science Foundation,China。
文摘Because of the limitations of electric vehicle(EV)battery technology and relevant supporting facilities,there is a great risk of breakdown of EVs during driving.The resulting driver“range anxiety”greatly affects the travel quality of EVs.These limitations should be overcome to promote the use of EVs.In this study,a method for travel path planning considering EV power supply was developed.First,based on real-time road conditions,a dynamic energy model of EVs was established considering the driving energy and accessory energy.Second,a multi-objective travel path planning model of EVs was constructed considering the power supply,taking the distance,time,energy,and charging cost as the optimization objectives.Finally,taking the actual traffic network of 15 km×15 km area in a city as the research object,the model was simulated and verified in MATLAB based on Dijkstra shortest path algorithm.The simulation results show that compared with the traditional route planning method,the total distance in the proposed optimal route planning method increased by 1.18%,but the energy consumption,charging cost,and driving time decreased by 11.62%,41.26%and 11.00%,respectively,thus effectively reducing the travel cost of EVs and improving the driving quality of EVs.
基金Manuscript received August 10, 2009 accepted September 8, 2010 Supported by National Natural Science Foundation of China 60874002）, Key Project of Shanghai Education Committee 09ZZ158）, Leading Academic Discipline Project of Shanghai Municipal Government （S30501）, and Innovation Fund Project For Craduate Student of Shanghai （JWCXSL1001）
基金Projects(ZR2013BL010,ZR2012DL05)supported by the Natural Science Foundation of Shandong Province,ChinaProject(4041412016)supported by the Research Excellence Award of Shandong University of Technology,ChinaProjects(2013GG03116,2011GG02115)supported by the Science and Technology Development Planning Project of Zibo,China
文摘High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synthetic high salinity wastewater was evaluated at laboratory scale during a 110-day operation.The reactor was operated in a 12 h cycle,and each cycle consisted of 0.25 h influent addition,8 h aeration,3 h anoxic reaction,0.5 h sedimentation and 0.25 h effluent withdrawal.Gradual increase in salinity gradient was applied during the acclimatization period.The acclimated SBBR system was demonstrated to be an effective process to remove organic compounds and ammonia nitrogen under high salinity conditions with chemical oxygen demand(COD)and ammonia nitrogen(NH3-N)removal efficiencies of 88% and 80%,respectively.The microscopic examination indicated that rather than rotifers or vorticella,the zoogloea,filamentous fungus mingled with a small quantity of swimming infusorians were dominant bacteria in SBBR system.The removal efficiencies close to 80% in COD and 75% in NH3-N were achieved at an organic loading rate(OLR)of 0.96 kg COD/(m3·d),pH of 7.0,salinity of 14 g/L and NH3-N of 30 mg/L.
基金Project(52004154) supported by the National Natural Science Foundation of ChinaProject(ZR2020QE002) supported by the Shandong Provincial Natural Science Foundation,ChinaProject(6142005190208) supported by the National Key Laboratory Foundation of China。
文摘This work aims to establish a suitable numerical simulation model for hybrid laser-electric arc heat source welding of dissimilar Mg alloys between AZ31 and AZ80. Based on the energy conservation law and Fourier’s law of heat conduction, the differential equations of the three-dimensional temperature field for nonlinear transient heat conduction are built. According to the analysis of nonlinear transient heat transfer, the equations representing initial conditions and boundary conditions are obtained. The “double ellipsoidal heat source + 3D Gaussian heat source”combination was chosen to construct the laser-electric arc hybrid heat source. The weld bead morphologies and the distribution of temperature, stress, displacement and plastic strains are numerically simulated. The actual welding experiments were performed by a hybrid laser-electric arc welding machine. The interaction mechanism between laser and electric arc in the hybrid welding of Mg alloys is discussed in detail. The hybrid heat source can promote the absorption of laser energy and electric arc in the molten pool, resulting in more uniform energy distribution in the molten pool and the corresponding improvement of welding parameters. This work can provide theoretical guidance and data supports for the optimization of the hybrid laser-electric arc welding processes for Mg alloys.
基金supported by the Natural Science Foundation of Shandong Province (Y2007H02)
文摘By employing function one-direction S-rough sets and rough law generation method based on function S-rough sets, ^-f-decomposition law and ^-F-decomposition rough law are proposed, and the measurement of rough law variation in the process of rough law ^-F-decomposition is researched. The concepts of law energy and attdbute ^-f-interference degree are presented, which make the variation of rough law become measurable. ^-f-decomposition law energy characteristic theorem, ^-f- decomposition law energy inequality theorem, ^-F-decomposition rough law energy characteristic theorem, and ^-f-decomposition law energy mean value theorem are presented.
基金Project(ZR2011BL005) supported by the Natural Science Foundation of Shandong Province,China
文摘Cation ion-exchange resin particles （CERP）/polyethersulfone （PES） hybrid catalytic membranes were prepared by immerse phase inversion for the esterification of different free fatty acids （FFAs） （such as, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and octadecadienoic acid） with methanol. The membranes were characterized by SEM, ion-exchange capacity and swelling degree test. It is found that dodecanoic acid has the highest FFAs conversion among the four acids for its stronger acidic and reactivity. Different effects of membrane annealing temperature, reaction temperature, molar ratio of methanol to FFAs and catalytic membrane loading on the esterification were investigated by the esterification of dodecanoic acid with methanol. The dodecanoic acid conversion reaches 97.5% trader the optimal condition when the esterification reaction lasted for 8 h.
文摘Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.
基金Project(ZR2011BL005)supported by the Natural Science Foundation of Shandong Province,China
文摘Graphite nanoplatelets were prepared by a novel magnetic-grinding method using self-made equipments. Under a variant magnetic field, magnetic needles collided at a high rotating speed and exfoliated pristine graphite into graphite nanoplatelets with high efficiency. The obtained graphite nanoplatelets are highly crystalline, and the thickness is less than 10 nm. Moreover, the surface area could reached 738.1 m^2/g with a grinding time of 4 h. Silanized graphite nanoplatelets can disperse well in SG 15W-40 engine oil and serve as lubricant additive. Tribological results indicate that the friction coefficient and wear-scar of the friction pairs are lower than 76% and 41%, respectively, by adding 1.5‰(mass fraction) of silanized graphite nanoplatelets. Notably, the functionalized graphite nanoplatelets can realize large-scale production and commercial application.
基金Project(50974147)supported by the National Natural Science Foundation of ChinaProject(2009ZRB01176)supported by the Natural Science Foundation of Shandong Province,China
文摘The grain size, textures and grain boundary plane distributions in a cold-rolled and annealed ferritic stainless steel were investigated by means of EBSD techniques. The results show that, following cold rolling with the thickness reduction of 85%, relatively low temperature （780℃） annealing brings an extremely sluggish grain growth and no grain texture develops when the annealing time varies from 5 min to 480 min. The free energy reduction of the system is mainly caused by the grain boundary plane re-orientation in addition to minor grain growth because the distributions of grain boundary planes are moderately preferred on { 100} according to the five parameter analyses （FPA） concerning the grain boundary plane characteristics. However, in the case of high-temperature （1 000 ℃） annealing, the average grain size does not increase until annealing time is prolonged to 90 min, after which extensive grain growth occurs and strong {100}（hkl） texture emerges whereas nearly random grain boundary plane distributions are observed. The free energy reduction of the system is most likely attributed to the selective growth.
基金Minist ry of Land and Resources and Geological Survey of China Foundation(121201050511)
文摘Land use and protection has become a global hot spot.How to use land resources is an important topic for the future socio-economic sustainable development.This paper analyzes the land use changes of Mata lake of Shandong province in China,from 1985's to 2000's using multi-temporal remotely sensed data including TM in the 1985s,ETM+in the 2000s and ancillary data such as soil use map,water map etc.The remote sensing imageries were calibrated,registered and geo-referenced,then classified by multi-source information data and remote sensing image interpretation expert system based on knowledge base.Five land use types were extracted from remote sensing imageries,that is,water body,agriculture land,rural settlement,bare land and none-use land.The total precision is 80.7% and Kappa index is 0.825.The analysis result of the remote sensing shows that during the past 15 years,water resource dropped off very promptly from 51.77 km2 to 16.65 km2 and bare land reduced greatly more than 60% in Mata lake region.With the development of the economy and agriculture areas,more and more water body and bare land converted to agriculture land use and rural settlement areas.Since last years,the Mata lake has been affected by natural factor,human activity and increasing population.So its land use pattern greatly changed from 1985 to 2000.The information of land use changes provided scientific supports for land planning and environmental protection.
基金Shandong Province Natural Science Foundation,China(ZR2020KB014,ZR2022QB206)the National Natural Science Foundation of China(22178001)+1 种基金Anhui Provincial Natural Science Foundation(2308085Y19)Research Project for Outstanding Youth of Department of Education of Anhui Province(2022AH030045).
文摘Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.
基金Supported by the Natural Science Foundation of Heilongjiang Province of China(LH2023C016)the Key Research and Development Program of Heilongjiang Province of China(2022ZX01A24)the National Modern Agricultural Industry Technology System(CARS36)。
文摘Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samples with different somatic cell counts were collected and preprocessing methods were studied.Variable selection algorithm based on hybrid strategy and modelling method based on ensemble learning were explored for somatic cell count detection.Detection model was used to diagnose subclinical mastitis and the results showed that near-infrared spectroscopy could be a tool to realize rapid detection of somatic cell count in milk.
文摘To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.
文摘In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method was utilized to prepare Nb_(4)AlC_(3)nanosheets,and then a piece of tapered fiber was adopted to fabricate Nb_(4)AlC_(3)-SA.It was found that the saturation intensity and modulation depth of the Nb_(4)AlC_(3)-SA are 2.02 MW/cm^(2)and 1.88%.Based on the Nb_(4)AlC_(3)-SA,a conventional soliton(CS)mode-locked EDF laser was achieved.The central wavelength,pulse duration,and pulse repetition rate were found to be 1565.65 nm,615.37 fs,and 24.63 MHz,respectively.The performance is competitive and particularly superior in terms of pulse duration.This study fully confirms that Nb_(4)AlC_(3)possesses marvellous nonlinear saturable absorption properties and opens new possibilities for further research on air-stable ultrafast photon-ic devices.
文摘To address the challenges of low detection accuracy caused by the diverse species,significant size variations,and complex growth environments of wheat pests in natural settings,a PSA-YOLO11n algorithm is proposed to enhance detection precision.Building upon the YOLO11n framework,the proposed improvements include three key components:1)SimCSPSPPF in Backbone:An improved Spatial Pyramid Pooling-Fast(SPPF)module,SimCSPSPPF,is integrated into the Backbone to reduce the number of channels in the hidden layers,thereby accelerating model training.2)PEC in Neck:The standard convolution layers in the Neck are replaced with Perception Enhancement Convolutions(PEC)to improve multi-scale feature extraction capabilities,enhancing detection speed.3)AWIoU Loss Function:The regression loss function is replaced with Adequate Wise IoU(AWIoU),addressing issues of bounding box distortion caused by the diversity in pest species and size variations,thereby improving the precision of bounding box localization.Experimental evaluations on the IP102 dataset demonstrate that PSA-YOLO11n achieves a mean Average Precision(mAP)of 89.10%,surpassing YOLO11n by 0.8%.Comparisons with other mainstream algorithms,including Faster R-CNN,RetinaNet,YOLOv5s,YOLOv8n,YOLOv10n,and YOLO11n,confirm that PSA-YOLO11n outperforms all baselines in terms of detection performance.These results highlight the algorithm’s capability to significantly improve the detection accuracy of multi-scale wheat pests in natural environments,providing an effective solution for pest management in wheat production.
