Due to their high-entropy effects,the high-entropy(HE)MAX-phase materials improve the comprehen-sive performance of MAX phases,opening up more possibilities for practical engineering applications.However,it is still c...Due to their high-entropy effects,the high-entropy(HE)MAX-phase materials improve the comprehen-sive performance of MAX phases,opening up more possibilities for practical engineering applications.However,it is still challenging to obtain S-containing high-entropy MAX phases because of the high volatilization behavior of sulfur,suffering from issues such as high reaction temperature and long re-action time of traditional synthesis methods.This paper proposes a novel process named as liquid metal assistant self-propagating high-temperature synthesis(LMA-SHS)for efficient synthesis of high-purity S-containing high-entropy MAX-phase materials.Low-melting-point metal(Sn or In)has been introduced into the raw mixture and melted into a liquid phase during the early stage of the SHS reaction.By serv-ing as a“binder”between transition metal atoms of the M-site due to the negative mixing enthalpy,this liquid phase can accelerate mass and heat transfer during the SHS process,ensuring a uniform solid solution of each element and realizing the synthesis of high-purity(TiNbVZr)_(2)SC in an extremely short time.The synthesis method for high-entropy MAX-phase materials developed in this study,i.e.,LMA-SHS,showing very short reaction time,low energy consumption,high yield,and low cost,has the promise to be a general energy-and resource-efficient route towards high-purity HE materials.展开更多
The Weiyuan Structure is the largest surface structure in the Sichuan Basin. However, the abundance of the Dengying Formation gas reservoir in the Weiyuan Structure is low. The height of the gas column is 244 m, but t...The Weiyuan Structure is the largest surface structure in the Sichuan Basin. However, the abundance of the Dengying Formation gas reservoir in the Weiyuan Structure is low. The height of the gas column is 244 m, but the integrated abundance is only 26.4%. After nearly 40 years of exploration, the Gaoshi1 Well and Moxi8 Well yielded gas flows that marked an important exploration success after the discovery of the Sinian Dengying Formation gas reservoir in the Weiyuan Structure, Sichuan Basin, Lower-Paleozoic in 1964. Combined with research examples of oil and gas migration and gas chimneys around the world, the authors used comprehensive geological-geophysical-geochemical research methods to provide a reasonable explanation of the low abundance of the gas reservoir in the Weiyuan Structure based on the surface and subsurface data. The latest research results show that(1) currently, the Weiyuan Structure is the apex of the Dengying Formation in the Mid-Sichuan Basin. The Guang'an, Longnüsi, Gaoshiti-Moxi, and Weiyuan structures are a series of traps in the Dengying Formation with gradual uplifting spill and closure points during the regional uplift of the Himalayan period. The natural gas of the Dengying Formation accumulated in different ways over a wide range and long distance in the Sichuan Basin.(2) At approximately 40 Ma, the Weiyuan area started to uplift and form the present structure, and it is the only outcropped area with the Triassic Jialingjiang Formation and Leikoupo Formation in the surface of the Sichuan Basin(except the steep structural belt in East Sichuan). Caused by the uplift and denudation, the core of the Weiyuan Structure has formed an escaping "skylight" for natural gas. The evidence of a gas chimney includes(1) the component percentage of non-hydrocarbon gas, which decreased from the bottom to the top,(2) the pressure coefficient is normal because the gas reservoir from the Upper Sinian to the Lower Permian commonly have a normal pressure coefficient(an average of 1.0), and(3) the isotope geochemistry of the argon mostly represents abiogenic characteristics of a deep source, and the 40 Ar/36 Ar ratio is as high as 2 855–5 222 in the Upper Permian. All of these characteristics provide sufficient evidence for a gas chimney effect. The characteristics of low abundance in the Weiyuan Structure can be a reference example for studying the late reconstruction of deep oil and gas reservoirs in the superimposed basins of western China.展开更多
Abundant bitumen can be discovered in the wells of Upper Sinian Dengying Formation in the Sichuan Basin and their peripheral outcrops sections.As the cracking product of a paleo-oil reservoir,the occurrence morphologi...Abundant bitumen can be discovered in the wells of Upper Sinian Dengying Formation in the Sichuan Basin and their peripheral outcrops sections.As the cracking product of a paleo-oil reservoir,the occurrence morphologies and distribution characteristics of bitumen in carbonate reservoirs can indicate the preservation,migration and other key information of(paleo-)oil and gas reservoirs.In order to provide reference and basis for the deep and ultra-deep oil and gas exploration in the Sichuan Basin and the basins in western China,this paper systematically studies the occurrence morphological characteristics of bitumen in deep and ultra-deep carbonate reservoirs in well Gaoshi 1 of the Sichuan Basin by carrying out thin section observation,scanning electron microscope-energy spectrum analysis and fluid inclusion organic geochemical analysis on the cores of the fourth member of Dengying Formation(Deng 4 Member).In addition,the coupling relationship between the occurrence morphology of bitumen and the key event of hydrocarbon accumulation is revealed.And the following research results are obtained.First,solid bitumen in the Deng 4 Member deep and ultra-deep reservoir has two types of occurrence morphology.The first type of bitumen adheres to pore walls in the shape of a rim or exists in pores in the form of sticky branch(e.g.,Wells Chuanshen 1 and Gaoshi 1).There are more obvious shrinkage fractures and residual pores generated by in-situ thermal cracking in this type of bitumen.And combined with fluid inclusion and burial thermal history,it can effectively indicate that a paleo-gas reservoir has been preserved so far since the paleo-oil reservoir was thermally cracked into carbonaceous bitumen.The second type of bitumen is distributed in intra-and inter-neogenic mineral crystals in pores disorderly in the shape of grain and band(e.g.,Wells Mashen 1 and Wutan 1)and it has obvious breaking edges.It reveals that after a paleo-oil reservoir was thermally cracked into carbonaceous bitumen,the paleo-gas reservoir suffered blowdown and gas escape and neogenic fluid minerals moved into reservoirs to fill in pores.In conclusion,the occurrence morphologies and distribution characteristics of bitumen in deep and ultra-deep carbonate reservoirs can effectively indicate the hydrocarbon accumulation and evolution process of paleo-oil and gas reservoirs.展开更多
The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the...The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the mechanical properties and damage/fracture evolution mechanisms of deep rock induced by microdynamic disturbance under three-dimensional stress states are unclear.Therefore,a true triaxial multilevel disturbance test method is proposed,which can completely simulate natural geostress,excavation stress redistribution(such as stress unloading,concentration and rotation),and subsequently the microdynamic disturbance triggering damaged rock failure.Based on a dynamic true triaxial test platform,true triaxial microdynamic disturbance tests under different frequency and amplitudes were carried out on monzogabbro.The results show that increasing amplitude or decreasing frequency diminishes the failure strength of monzogabbro.Deformation modulus gradually decreases during disturbance failure.As frequency and amplitude increase,the degradation rate of deformation modulus decreases slightly,disturbance dissipated energy increases significantly,and disturbance deformation anisotropy strengthens obviously.A damage model has been proposed to quantitatively characterize the disturbance-induced damage evolution at different frequency and amplitude under true triaxial stress.Before disturbance failure,the micro-tensile crack mechanism is dominant,and the micro-shear crack mechanism increases significantly at failure.With the increase of amplitude and frequency,the micro-shear crack mechanism increases.When approaching disturbance failure,the acoustic emission fractal dimension changes from a stable value to local large oscillation,and finally increases sharply to a high value at failure.Finally,the disturbance-induced failure mechanism of surrounding rock in deep engineering is clearly elucidated.展开更多
Objective Berberine(BBR)has emerged as a promising therapeutic agent for nonalcoholic fatty liver disease(NAFLD).This study aims to elucidate the underlying molecular mechanisms.Methods In this study,db/db mice were c...Objective Berberine(BBR)has emerged as a promising therapeutic agent for nonalcoholic fatty liver disease(NAFLD).This study aims to elucidate the underlying molecular mechanisms.Methods In this study,db/db mice were chosen as an animal model for NAFLD.A total of 10 healthy C57BL/6J mice and 30 db/db mice were randomly allocated to one of 4 groups:the normal control(NC)group,the diabetic control(DC)group,the Metformin(MET)therapy group,and the BBR therapy group.The total cholesterol(TC),triacylglycerol(TG),low-density lipoprotein cholesterol(LDL-c),high-density lipoprotein cholesterol(HDL-c),aspartate aminotransferase(AST)and alanine aminotransferase(ALT)levels in the serum were measured.The glutathione peroxidase(GSH-Px),glutathione(GSH),malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT),interleukin(IL)-1β,tumor necrosis factor(TNF)-αand monocyte chemotactic protein 1(MCP-1)levels in liver tissue were measured.Hematoxylin and eosin(H&E),acid-Schiff(PAS)and TUNEL stanning was performed for histopathological analysis.Western blotting and immunohistochemistry were conducted to detect the expression levels of key proteins in the AMPK/SIRT1 pathway.Results BBR could improve lipid metabolism,attenuate hepatic steatosis and alleviate liver injury significantly.The excessive oxidative stress,high levels of inflammation and abnormal apoptosis in db/db mice were reversed after BBR intervention.BBR clearly changed the expression of AMP-activated protein kinase(AMPK)/Sirtuin 1(SIRT1),and their downstream proteins.Conclusion BBR could reverse NAFLD-related liver injury,likely by activating the AMPK/SIRT1 signaling pathway to inhibit oxidative stress,inflammation and apoptosis in hepatic tissue.展开更多
A novel layered perovskite tantalate phosphor Sr_(3)LaTa_(3)O_(12):Sm^(3+)(SLTO:Sm^(3+)) with orange-red emission was obtained for the first time via the solid-phase synthetic method. The phase purity, surface morphol...A novel layered perovskite tantalate phosphor Sr_(3)LaTa_(3)O_(12):Sm^(3+)(SLTO:Sm^(3+)) with orange-red emission was obtained for the first time via the solid-phase synthetic method. The phase purity, surface morphology,element distribution and luminescent properties of the SLTO:xSm^(3+)(x= 0.01 mol%-0.30 mol%) phosphors were investigated. Under 408 nm excitation, the optimum doped SLTO:0.10Sm^(3+) phosphor emits orangered light at 598 nm with the highest emission peak(4G_(5/2)→6H_(7/2)). The critical energy transfer distance is 1.687 nm. The prepared SLTO:0.10Sm^(3+)phosphor has excellent thermal stability with temperature quenching temperature(T_(0.5)> 500 K) and high activation energy(E_(a)= 0.25 e V). Through calculation, the chromaticity coordinates of all samples are concentrated in the orange-red area, and the color purity reaches 99%. The fabricated white light-emitting diode(w-LED) has a good correlated color temperature(5132 K), a high R_(a)(89), and the CIE chromaticity coordinates(0.340, 0.327). Consequently, the superiority of orange-red-emitting tantalate SLTO:Sm^(3+) phosphors for w-LEDs is demonstrated.展开更多
To analyze the correlation between coronary heart disease and the possible risk factors such as age, gender, hypertension, dyslipidemia, smoking, diabetes, uric acid and plasma fibrinogen, to screen the main risk fact...To analyze the correlation between coronary heart disease and the possible risk factors such as age, gender, hypertension, dyslipidemia, smoking, diabetes, uric acid and plasma fibrinogen, to screen the main risk factors of coronary heart disease in the elderly and evaluate the intervention status of coronary heart disease in the elderly. In the unchangeable risk factors, age is still the main risk factor of coronary heart disease;in terms of gender, the onset age of female coronary heart disease is later than that of male, but the complications and mortality rate are higher than that of male, and the risk factors are more than that of male. The first level prevention needs doctors and patients to establish a mutual trust relationship, and actively intervene to reduce the total risk of cardiovascular disease. Drug compliance management should be strengthened in secondary prevention.展开更多
Objective:To explore the expression of CD151 in gastric cancer tissues and its clinical significance.Methods:Immunohistochemistry was employed to detect the expression of CD151 in gastric cancer tissues and adjacent n...Objective:To explore the expression of CD151 in gastric cancer tissues and its clinical significance.Methods:Immunohistochemistry was employed to detect the expression of CD151 in gastric cancer tissues and adjacent normal tissues.The relationship between CD151 expression and the clinicopathological characteristics of gastric cancer was analyzed.Results:The expression of CD151 in gastric cancer tissues was significantly higher than in adjacent normal tissues(P<0.05).It was associated with the degree of differentiation,depth of invasion,lymph node metastasis,and TNM staging of gastric cancer.The survival time of patients with high CD151 expression was significantly shorter than that of those with low expression(P<0.05).Conclusion:High expression of CD151 in gastric cancer tissues is correlated with the malignant biological behavior of gastric cancer and can serve as an indicator for evaluating the prognosis of gastric cancer.展开更多
Sichuan Basin is one of the uppermost petroliferous basins in China. It experienced three evolutionary phases which were marine carbonate platform （Ediacaran to Late Triassic）, Indosinian-Yanshanian orogeny foreland...Sichuan Basin is one of the uppermost petroliferous basins in China. It experienced three evolutionary phases which were marine carbonate platform （Ediacaran to Late Triassic）, Indosinian-Yanshanian orogeny foreland basin （Late Triassic to Late Cretaceous） and uplift and tectonic modification （Late Cretaceous to Quaternary）. The present-day tectonics of the Sichuan Ba- sin and its periphery are characterized by three basic elements which are topography, basement type and surface structure, and two settings （plate margin and interior）. Therefore, be subdivided into five units which have different structure and tectonic history. The basin contains five different sets of source rocks with thickness up to 2 500 m. These source rocks were well preserved due to the presence of Middel-Lower Triassic evaporites （〉-200 m） and thick terrestrial sediments filling in the Indosinian-Yanshanian foreland basin （〉3 000 m）. The uplift and erosion since Late Cretaceous has significant influence on cross-strata migration and accumulation of oil and gas. The multi-phase evolution of the basin and its superimposed tectonic elements, good petroleum geologic conditions and diverse petroleum systems reveal its bright exploration prospects.展开更多
To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutio...To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutions(5,10,20,30 km),nesting grids(15 and 5 km),different vertical resolutions(35-layers,28-layers,20-layers)and different top maximum pressures(1 000,2 000,3 500,5 000 Pa)had been used in the mesoscale numerical model WRF to simulate the Typhoon Kai-tak.The simulation results of typhoon track,wind speed and sea level pressure at different horizontal and vertical resolutions have been compared and analyzed.The horizontal and vertical resolutions of the model have limited effect on the simulation effect of the typhoon track.Different horizontal and vertical resolutions have obvious effects on typhoon strength(defined by wind speed)and intensity(defined by sea level pressure,SLP),especially for sea level pressure.The typhoon intensity simulated by the high-resolution model is closer to the real situation and the nesting grids can improve computational accuracy and efficiency.The simulation results affected by vertical resolution using 35-layers is better than the simulation results using 20-layers and 28-layers simulations.Through comparison and analysis,the horizontal and vertical resolutions of WRF model are finally determined as follows:the two-way nesting grid of 15 and 5 km is comprehensively determined,and the vertical layers is 35-layers,the top maximum pressure is 2 000 Pa.展开更多
A novel red-emitting phosphor tantalate Ca_(2)YTaO_(6):Eu^(3+)was synthesized by a solid-state reaction.The purity and surface morphology of the phosphors were characterized.The Ca_(2)YTaO_(6):Eu^(3+)phosphors show a ...A novel red-emitting phosphor tantalate Ca_(2)YTaO_(6):Eu^(3+)was synthesized by a solid-state reaction.The purity and surface morphology of the phosphors were characterized.The Ca_(2)YTaO_(6):Eu^(3+)phosphors show a sharp emission peak at 612 nm under near-ultraviolet(n-UV) at 395 nm because of the ^(5)D0→^(7)F_(2) transition of Eu^(3+).The optimal Eu^(3+)doping concentration in Ca_(2)YTaO_(6) is 40 mol% and the critical energy-transfer distance of Eu^(3+)ions was calculated to be 0.9 nm.The emission spectra of Ca_(2)YTaO_(6):Eu_(3+)from 300 to 480 K were investigated.The thermal-quenching temperature(T_(0.5)) of Ca_(2)YTaO_(6):Eu^(3+)is above 480 K.The color purity of Ca_(2)YTaO_(6):40 mol%Eu^(3+)is as high as 99.8%.The luminescence lifetime of Ca_(2)YTaO_(6):40 mol%Eu^(3+)was also discussed.The high color purity and high thermal stability of Eu^(3+)-doped Ca_(2)YTaO_(6) phosphors contribute to its application value in white lightemitting diodes(w-LEDs).展开更多
AIM: To compare synchronous laparoscopic cholecystectomy (LC) combined with endoscopic sphincterotomy (EST) and sequential LC combined with EST for treating cholecystocholedocholithiasis. METHODS: A total of 150 patie...AIM: To compare synchronous laparoscopic cholecystectomy (LC) combined with endoscopic sphincterotomy (EST) and sequential LC combined with EST for treating cholecystocholedocholithiasis. METHODS: A total of 150 patients were included and retrospectively studied. Among these, 70 were selected for the synchronous operation, in which the scheme was endoscopic retrograde cholangiopancreatography combined with EST during LC. The other 80 patients were selected for the sequential operation, in which the scheme involved first cutting the papillary muscle under endoscopy and then performing LC. The indexes in the two groups, including the operation time, the success rate, the incidence of complications, and the length of the hospital stay, were observed.RESULTS: There were no significant differences between the groups in terms of the numbers of patients, sex distribution, age, American Society of Anesthesiologists score, serum bilirubin, γ-glutamyl transpeptidase, mean diameter of common bile duct stones, and previous medical and surgical history (P = 0.54, P = 0.18, P = 0.52, P = 0.22, P = 0.32, P = 0.42, P = 0.68, P = 0.70, P = 0.47 and P = 0.57). There was no significant difference in the surgical operation time between the two groups (112.1 ± 30.8 min vs 104.9 ± 18.2 min). Compared with the sequential operation group, the incidence of pancreatitis was lower (1.4% vs 6.3%), the incidence of hyperamylasemia (1.4% vs 10.0%, P < 0.05) was significantly reduced, and the length of the hospital stay was significantly shortened in the synchronous operation group (3 d vs 4.5 d, P < 0.001). CONCLUSION: For treatment of cholecystocholedo-cholithiasis, synchronous LC combined with EST reduces incidence of complications, decreases length of hospital stay, simplifies the surgical procedure, and reduces operation time.展开更多
In the core of a molten salt fast reactor(MSFR),heavy metal fuel and fission products can be dissolved in a molten fluoride salt to form a eutectic mixture that acts as both fuel and coolant.Fission energy is released...In the core of a molten salt fast reactor(MSFR),heavy metal fuel and fission products can be dissolved in a molten fluoride salt to form a eutectic mixture that acts as both fuel and coolant.Fission energy is released from the fuel salt and transferred to the second loop by fuel salt circulation.Therefore,the MSFR is characterized by strong interaction between the neutronics and the thermal hydraulics.Moreover,recirculation flow occurs,and nuclear heat is accumulated near the fertile blanket,which significantly affects both the flow and the temperature fields in the core.In this work,to further optimize the conceptual geometric design of the MSFR,three geometries of the core and fertile blanket are proposed,and the thermal-hydraulic characteristics,including the three-dimensional flow and temperature fields of the fuel and fertile salts,are simulated and analyzed using a coupling scheme between the open source codes OpenMC and OpenFOAM.The numerical results indicate that a flatter core temperature distribution can be obtained and the hot spot and flow stagnation zones that appear in the upper and lower parts of the core center near the reflector can be eliminated by curving both the top and bottom walls of the core.Moreover,eight cooling loops with a total flow rate of0.0555 m3 s-1 ensur an acceptable temperature distribusure an acceptable temperature distribution in the fertile blanket.展开更多
The simulating waves nearshore(SWAN) model has typically been designed for wave simulations in near-shore regions. In this study, the model's applicability to the simulation of typhoon waves in the South China Sea...The simulating waves nearshore(SWAN) model has typically been designed for wave simulations in near-shore regions. In this study, the model's applicability to the simulation of typhoon waves in the South China Sea(SCS) was evaluated. A blended wind field, consisting of an interior domain based on Fujita's model and an exterior domain based on Takahashi's model, was used as the driving wind field. The waves driven by Typhoon Kai-tak over the SCS that occurred in 2012 were selected for the numerical simulation research. Sensitivity analyses of time step, grid resolution, and angle resolution were performed in order to obtain optimal model settings. Through sensitivity analyses, it can be found that the time step has a large influence on the results, while grid resolution and angle resolution have a little effect on the results.展开更多
Desalination by freezing/thawing method was a very important method to obtain fresh water from seawater.In this work,desalination by freezing/thawing method was conducted with initial sodium chloride of 3.5 wt% in con...Desalination by freezing/thawing method was a very important method to obtain fresh water from seawater.In this work,desalination by freezing/thawing method was conducted with initial sodium chloride of 3.5 wt% in consideration of stirring speed,freezing time and subcooling.The subcooling ranged from 1.2 K to 4 K.The optimum conditions for desalination in this work were stirring speed of 200 r·min^−1,freezing time of 120 min,and subcooling of 3 K.The results also showed that sodiumchloride cannot be effectively removed by once freezing/thawing process.The maximumremoval efficiency of sodiumchloride was 64.3%.Two major reasons resulting in the impurity of obtained melted water by freezing/thawing method were proposed.The first reason was the inevitable adhesion of salt solution to the surface of ice,which could be removed easily by distilled water flushing.The second reason was that salt solution was heterogeneously wrapped in the accumulated ice,which was difficult to be removed by distilled water flushing.The liquid flushing method was proposed to verify the conjecture,and the results were in accordance with the two reasons mentioned above.Additional method,such as multiple flushing liquid method,was suggested to be used during the freezing/thawing process for effectively removing sodium chloride,and obtaining fresh water.展开更多
In stroke rehabilitation,rehabilitation equipments can help with the training.But traditional equipments are not convenient to carry,which limits patients to use related rehabilitation techniques.To solve this kind of...In stroke rehabilitation,rehabilitation equipments can help with the training.But traditional equipments are not convenient to carry,which limits patients to use related rehabilitation techniques.To solve this kind of problem,a new embedded rehabilitation system based on brain computer interface(BCI)is proposed in this paper.The system is based on motor imagery(MI)therapy,in which electroencephalogram(EEG)is evoked by grasping motor imageries of left and right hands,then collected by a wearable device.The EEG is transmitted to a Raspberry Pie processing unit through Bluetooth and decoded as the instructions to control the equipment extension.Users experience the limb movement through the visual feedback so as to achieve active rehabilitation.A pilot study shows that the user can control the movement of the rehabilitation equipment through his mind,and the equipment is convenient to carry.The study provides a new way to stroke rehabilitation.展开更多
Cyan-emitting Ca_(9)NaGd_(2/3)(PO_(4))_(7):Eu^(2+)phosphors were synthesized via high temperature solid-state route.X-ray powder diffraction(XRD)and scanning electron microscopy(SEM)were used to verify the phase and m...Cyan-emitting Ca_(9)NaGd_(2/3)(PO_(4))_(7):Eu^(2+)phosphors were synthesized via high temperature solid-state route.X-ray powder diffraction(XRD)and scanning electron microscopy(SEM)were used to verify the phase and morphology of the Ca_(9)NaGd_(2/3)(PO_(4))_(7):Eu^(2+)(CNGP:Eu^(2+))phosphors.The as-obtained phosphor exhibits a broad excitation band of 250-420 nm,which is near the ultraviolet region.An intense asymmetric cyan emission at 496 nm corresponds to the 5 d-4 f transition of Eu^(2+).The multiplesite luminescent properties of Eu^(2+)ions in CNGP benefit from versatile structure ofβ-Ca3(PO4)2 compounds.The effective energy transfer distance is 5.46 nm(through the spectral overlap calculation),validating that the resonant energy migration type is via dipole-dipole interaction mechanism.Compared to the initial one at room temperature,the luminescent intensity of CNGP:Eu^(2+)phosphor can maintain 77%as it is heated up to 420 K.A white light-emitting diode(WLED)with excellent luminesce nt properties was successfully fabricated.Moreover,the CIE chromaticity coordinates of fabricated WLED driven by changing current just change slightly.展开更多
Novel yellow-emitting phosphors of Dy^(3+)-doped double perovskite Ca_(2)MgTeO_(6) were synthesized by using a conventional high-temperature solid-state reaction.The phase purity,particle morphology,size distribution,...Novel yellow-emitting phosphors of Dy^(3+)-doped double perovskite Ca_(2)MgTeO_(6) were synthesized by using a conventional high-temperature solid-state reaction.The phase purity,particle morphology,size distribution,elemental composition,luminescence properties,and luminescence decay curves of the resulting products were then analyzed in detail.The Ca_(2)MgTeO_(6):Dy^(3+),Na^(+) phosphors show three emission peaks after near-ultraviolet excitation at 350 nm,which correspond to ^(4)F_(9/2)→^(6)H_(11/2),^(4)F_(9/2)→^(6)H_(13/2),and ^(4)F_(9/2)→^(6)H_(13/2) transitions,respectively.Among them,the strongest peak is observed at 573 nm.The best doping content of Dy^(3+)in Ca_(2)MgTeO_(6):xDy^(3+),xNa^(+) phosphors is x=5 mol%.The calculated critical distance of energy transfer between Dy^(3+) ions is 1.6 nm.Luminescence quenching is confirmed to be due to dipole-dipole interactions among Dy^(3+) ions.The phosphors show excellent thermal stability with high activation energy(0.27 eV).The Commission Internationale de l’Eclairage(CIE) chromaticity coordinates of the Ca_(2)MgTeO_(6) Dy^(3+),Na^(+) phosphors are located in the yellow region.White light-emitting diodes(w-LEDs) were fabricated with a high color rendering index(R_(a)) of 88 and a good correlated color temperature(CCT) of 5440 K.All observed properties indicate that Ca_(2)MgTeO_(6):Dy^(3+),Na^(+) phosphors have potential applications in display and photonic devices.展开更多
基金supported by the Shanghai Local Capacity Building Program(No.23010500700)the Project of Shanghai Municipal Science and Technology Commission(No.22DZ2291100)the Qinglan Project of Jiangsu Province,and the Open Project of Jiangsu Provincial Key Laboratory of Eco-Environmental Materials.
文摘Due to their high-entropy effects,the high-entropy(HE)MAX-phase materials improve the comprehen-sive performance of MAX phases,opening up more possibilities for practical engineering applications.However,it is still challenging to obtain S-containing high-entropy MAX phases because of the high volatilization behavior of sulfur,suffering from issues such as high reaction temperature and long re-action time of traditional synthesis methods.This paper proposes a novel process named as liquid metal assistant self-propagating high-temperature synthesis(LMA-SHS)for efficient synthesis of high-purity S-containing high-entropy MAX-phase materials.Low-melting-point metal(Sn or In)has been introduced into the raw mixture and melted into a liquid phase during the early stage of the SHS reaction.By serv-ing as a“binder”between transition metal atoms of the M-site due to the negative mixing enthalpy,this liquid phase can accelerate mass and heat transfer during the SHS process,ensuring a uniform solid solution of each element and realizing the synthesis of high-purity(TiNbVZr)_(2)SC in an extremely short time.The synthesis method for high-entropy MAX-phase materials developed in this study,i.e.,LMA-SHS,showing very short reaction time,low energy consumption,high yield,and low cost,has the promise to be a general energy-and resource-efficient route towards high-purity HE materials.
基金financially supported by the Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technologythe 973 Program of China (No. 2012CB214805)+1 种基金the SINOPEC research project (No. P16109)the National Science and Technology Major Project of China (No. 2017ZX05005003-007)
文摘The Weiyuan Structure is the largest surface structure in the Sichuan Basin. However, the abundance of the Dengying Formation gas reservoir in the Weiyuan Structure is low. The height of the gas column is 244 m, but the integrated abundance is only 26.4%. After nearly 40 years of exploration, the Gaoshi1 Well and Moxi8 Well yielded gas flows that marked an important exploration success after the discovery of the Sinian Dengying Formation gas reservoir in the Weiyuan Structure, Sichuan Basin, Lower-Paleozoic in 1964. Combined with research examples of oil and gas migration and gas chimneys around the world, the authors used comprehensive geological-geophysical-geochemical research methods to provide a reasonable explanation of the low abundance of the gas reservoir in the Weiyuan Structure based on the surface and subsurface data. The latest research results show that(1) currently, the Weiyuan Structure is the apex of the Dengying Formation in the Mid-Sichuan Basin. The Guang'an, Longnüsi, Gaoshiti-Moxi, and Weiyuan structures are a series of traps in the Dengying Formation with gradual uplifting spill and closure points during the regional uplift of the Himalayan period. The natural gas of the Dengying Formation accumulated in different ways over a wide range and long distance in the Sichuan Basin.(2) At approximately 40 Ma, the Weiyuan area started to uplift and form the present structure, and it is the only outcropped area with the Triassic Jialingjiang Formation and Leikoupo Formation in the surface of the Sichuan Basin(except the steep structural belt in East Sichuan). Caused by the uplift and denudation, the core of the Weiyuan Structure has formed an escaping "skylight" for natural gas. The evidence of a gas chimney includes(1) the component percentage of non-hydrocarbon gas, which decreased from the bottom to the top,(2) the pressure coefficient is normal because the gas reservoir from the Upper Sinian to the Lower Permian commonly have a normal pressure coefficient(an average of 1.0), and(3) the isotope geochemistry of the argon mostly represents abiogenic characteristics of a deep source, and the 40 Ar/36 Ar ratio is as high as 2 855–5 222 in the Upper Permian. All of these characteristics provide sufficient evidence for a gas chimney effect. The characteristics of low abundance in the Weiyuan Structure can be a reference example for studying the late reconstruction of deep oil and gas reservoirs in the superimposed basins of western China.
基金Project supported by the National Scientific Fund Project“Fundamental Study on Marine Deep-Layer Oil and Gas Enrichment Mechanism and Key Engineering Technologies”(No.U19B6003)Key Scientific and Technological Planning Research Project of the Sichuan Basin“Process and Mechanism of Hydrocarbon Accumulation in the Sinian Dengying Formation,the Sichuan Basin”(No.2018JZ0078)Scientific and Technological Planning Application Fundamental Research Project(No.2019YJ0500).
文摘Abundant bitumen can be discovered in the wells of Upper Sinian Dengying Formation in the Sichuan Basin and their peripheral outcrops sections.As the cracking product of a paleo-oil reservoir,the occurrence morphologies and distribution characteristics of bitumen in carbonate reservoirs can indicate the preservation,migration and other key information of(paleo-)oil and gas reservoirs.In order to provide reference and basis for the deep and ultra-deep oil and gas exploration in the Sichuan Basin and the basins in western China,this paper systematically studies the occurrence morphological characteristics of bitumen in deep and ultra-deep carbonate reservoirs in well Gaoshi 1 of the Sichuan Basin by carrying out thin section observation,scanning electron microscope-energy spectrum analysis and fluid inclusion organic geochemical analysis on the cores of the fourth member of Dengying Formation(Deng 4 Member).In addition,the coupling relationship between the occurrence morphology of bitumen and the key event of hydrocarbon accumulation is revealed.And the following research results are obtained.First,solid bitumen in the Deng 4 Member deep and ultra-deep reservoir has two types of occurrence morphology.The first type of bitumen adheres to pore walls in the shape of a rim or exists in pores in the form of sticky branch(e.g.,Wells Chuanshen 1 and Gaoshi 1).There are more obvious shrinkage fractures and residual pores generated by in-situ thermal cracking in this type of bitumen.And combined with fluid inclusion and burial thermal history,it can effectively indicate that a paleo-gas reservoir has been preserved so far since the paleo-oil reservoir was thermally cracked into carbonaceous bitumen.The second type of bitumen is distributed in intra-and inter-neogenic mineral crystals in pores disorderly in the shape of grain and band(e.g.,Wells Mashen 1 and Wutan 1)and it has obvious breaking edges.It reveals that after a paleo-oil reservoir was thermally cracked into carbonaceous bitumen,the paleo-gas reservoir suffered blowdown and gas escape and neogenic fluid minerals moved into reservoirs to fill in pores.In conclusion,the occurrence morphologies and distribution characteristics of bitumen in deep and ultra-deep carbonate reservoirs can effectively indicate the hydrocarbon accumulation and evolution process of paleo-oil and gas reservoirs.
基金the financial support from the National Natural Science Foundation of China(No.52109119)the Guangxi Natural Science Foundation(No.2021GXNSFBA075030)+2 种基金the Guangxi Science and Technology Project(No.Guike AD20325002)the Chinese Postdoctoral Science Fund Project(No.2022M723408)the Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(China Institute of Water Resources and Hydropower Research)(No.IWHR-SKL-202202)。
文摘The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the mechanical properties and damage/fracture evolution mechanisms of deep rock induced by microdynamic disturbance under three-dimensional stress states are unclear.Therefore,a true triaxial multilevel disturbance test method is proposed,which can completely simulate natural geostress,excavation stress redistribution(such as stress unloading,concentration and rotation),and subsequently the microdynamic disturbance triggering damaged rock failure.Based on a dynamic true triaxial test platform,true triaxial microdynamic disturbance tests under different frequency and amplitudes were carried out on monzogabbro.The results show that increasing amplitude or decreasing frequency diminishes the failure strength of monzogabbro.Deformation modulus gradually decreases during disturbance failure.As frequency and amplitude increase,the degradation rate of deformation modulus decreases slightly,disturbance dissipated energy increases significantly,and disturbance deformation anisotropy strengthens obviously.A damage model has been proposed to quantitatively characterize the disturbance-induced damage evolution at different frequency and amplitude under true triaxial stress.Before disturbance failure,the micro-tensile crack mechanism is dominant,and the micro-shear crack mechanism increases significantly at failure.With the increase of amplitude and frequency,the micro-shear crack mechanism increases.When approaching disturbance failure,the acoustic emission fractal dimension changes from a stable value to local large oscillation,and finally increases sharply to a high value at failure.Finally,the disturbance-induced failure mechanism of surrounding rock in deep engineering is clearly elucidated.
基金supported by grants from the National Natural Science Foundation of China(No.81803799)Hubei Province Natural Science Foundation of China(No.2022CFB092).
文摘Objective Berberine(BBR)has emerged as a promising therapeutic agent for nonalcoholic fatty liver disease(NAFLD).This study aims to elucidate the underlying molecular mechanisms.Methods In this study,db/db mice were chosen as an animal model for NAFLD.A total of 10 healthy C57BL/6J mice and 30 db/db mice were randomly allocated to one of 4 groups:the normal control(NC)group,the diabetic control(DC)group,the Metformin(MET)therapy group,and the BBR therapy group.The total cholesterol(TC),triacylglycerol(TG),low-density lipoprotein cholesterol(LDL-c),high-density lipoprotein cholesterol(HDL-c),aspartate aminotransferase(AST)and alanine aminotransferase(ALT)levels in the serum were measured.The glutathione peroxidase(GSH-Px),glutathione(GSH),malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT),interleukin(IL)-1β,tumor necrosis factor(TNF)-αand monocyte chemotactic protein 1(MCP-1)levels in liver tissue were measured.Hematoxylin and eosin(H&E),acid-Schiff(PAS)and TUNEL stanning was performed for histopathological analysis.Western blotting and immunohistochemistry were conducted to detect the expression levels of key proteins in the AMPK/SIRT1 pathway.Results BBR could improve lipid metabolism,attenuate hepatic steatosis and alleviate liver injury significantly.The excessive oxidative stress,high levels of inflammation and abnormal apoptosis in db/db mice were reversed after BBR intervention.BBR clearly changed the expression of AMP-activated protein kinase(AMPK)/Sirtuin 1(SIRT1),and their downstream proteins.Conclusion BBR could reverse NAFLD-related liver injury,likely by activating the AMPK/SIRT1 signaling pathway to inhibit oxidative stress,inflammation and apoptosis in hepatic tissue.
基金Project supported by the Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications(2019XGJSKFJJ01)the Construction Program of the Key Discipline of the Education Department in Hunan Province(18A465)+1 种基金the Natural Science Foundation of Hunan Province(2023JJ31000)the Natural Science Foundation of Shaanxi Province(2022NY-224)。
文摘A novel layered perovskite tantalate phosphor Sr_(3)LaTa_(3)O_(12):Sm^(3+)(SLTO:Sm^(3+)) with orange-red emission was obtained for the first time via the solid-phase synthetic method. The phase purity, surface morphology,element distribution and luminescent properties of the SLTO:xSm^(3+)(x= 0.01 mol%-0.30 mol%) phosphors were investigated. Under 408 nm excitation, the optimum doped SLTO:0.10Sm^(3+) phosphor emits orangered light at 598 nm with the highest emission peak(4G_(5/2)→6H_(7/2)). The critical energy transfer distance is 1.687 nm. The prepared SLTO:0.10Sm^(3+)phosphor has excellent thermal stability with temperature quenching temperature(T_(0.5)> 500 K) and high activation energy(E_(a)= 0.25 e V). Through calculation, the chromaticity coordinates of all samples are concentrated in the orange-red area, and the color purity reaches 99%. The fabricated white light-emitting diode(w-LED) has a good correlated color temperature(5132 K), a high R_(a)(89), and the CIE chromaticity coordinates(0.340, 0.327). Consequently, the superiority of orange-red-emitting tantalate SLTO:Sm^(3+) phosphors for w-LEDs is demonstrated.
文摘To analyze the correlation between coronary heart disease and the possible risk factors such as age, gender, hypertension, dyslipidemia, smoking, diabetes, uric acid and plasma fibrinogen, to screen the main risk factors of coronary heart disease in the elderly and evaluate the intervention status of coronary heart disease in the elderly. In the unchangeable risk factors, age is still the main risk factor of coronary heart disease;in terms of gender, the onset age of female coronary heart disease is later than that of male, but the complications and mortality rate are higher than that of male, and the risk factors are more than that of male. The first level prevention needs doctors and patients to establish a mutual trust relationship, and actively intervene to reduce the total risk of cardiovascular disease. Drug compliance management should be strengthened in secondary prevention.
文摘Objective:To explore the expression of CD151 in gastric cancer tissues and its clinical significance.Methods:Immunohistochemistry was employed to detect the expression of CD151 in gastric cancer tissues and adjacent normal tissues.The relationship between CD151 expression and the clinicopathological characteristics of gastric cancer was analyzed.Results:The expression of CD151 in gastric cancer tissues was significantly higher than in adjacent normal tissues(P<0.05).It was associated with the degree of differentiation,depth of invasion,lymph node metastasis,and TNM staging of gastric cancer.The survival time of patients with high CD151 expression was significantly shorter than that of those with low expression(P<0.05).Conclusion:High expression of CD151 in gastric cancer tissues is correlated with the malignant biological behavior of gastric cancer and can serve as an indicator for evaluating the prognosis of gastric cancer.
基金supported by the National Basic Research Program of China (No. 2012CB214805)the National Natural Science Foundation of China (Nos. 41230313, 41402119, 2017JQ0025, 41472017, 41572111)
文摘Sichuan Basin is one of the uppermost petroliferous basins in China. It experienced three evolutionary phases which were marine carbonate platform （Ediacaran to Late Triassic）, Indosinian-Yanshanian orogeny foreland basin （Late Triassic to Late Cretaceous） and uplift and tectonic modification （Late Cretaceous to Quaternary）. The present-day tectonics of the Sichuan Ba- sin and its periphery are characterized by three basic elements which are topography, basement type and surface structure, and two settings （plate margin and interior）. Therefore, be subdivided into five units which have different structure and tectonic history. The basin contains five different sets of source rocks with thickness up to 2 500 m. These source rocks were well preserved due to the presence of Middel-Lower Triassic evaporites （〉-200 m） and thick terrestrial sediments filling in the Indosinian-Yanshanian foreland basin （〉3 000 m）. The uplift and erosion since Late Cretaceous has significant influence on cross-strata migration and accumulation of oil and gas. The multi-phase evolution of the basin and its superimposed tectonic elements, good petroleum geologic conditions and diverse petroleum systems reveal its bright exploration prospects.
基金The National Natural Science Foundation of China under contract Nos 51809023,51839002 and 51879015the Open Research Foundation of the Key Laboratory of the Pearl River Estuarine Dynamics and Associated Process Regulation,the Ministry of Water Resources under contract No.2018KJ03
文摘To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutions(5,10,20,30 km),nesting grids(15 and 5 km),different vertical resolutions(35-layers,28-layers,20-layers)and different top maximum pressures(1 000,2 000,3 500,5 000 Pa)had been used in the mesoscale numerical model WRF to simulate the Typhoon Kai-tak.The simulation results of typhoon track,wind speed and sea level pressure at different horizontal and vertical resolutions have been compared and analyzed.The horizontal and vertical resolutions of the model have limited effect on the simulation effect of the typhoon track.Different horizontal and vertical resolutions have obvious effects on typhoon strength(defined by wind speed)and intensity(defined by sea level pressure,SLP),especially for sea level pressure.The typhoon intensity simulated by the high-resolution model is closer to the real situation and the nesting grids can improve computational accuracy and efficiency.The simulation results affected by vertical resolution using 35-layers is better than the simulation results using 20-layers and 28-layers simulations.Through comparison and analysis,the horizontal and vertical resolutions of WRF model are finally determined as follows:the two-way nesting grid of 15 and 5 km is comprehensively determined,and the vertical layers is 35-layers,the top maximum pressure is 2 000 Pa.
基金The work was supported by Undergraduate Innovation Fund of Northwest A&F UniversityChina(201910712069)+3 种基金Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications(2019XGJSKFJJ01)the Construction Program of the key discipline in Hunan Provincethe Projects of the Education Department of Hunan Province(No.18A465)Science and Technology Plan Project of Chenzhou City(jsyf2017014)。
文摘A novel red-emitting phosphor tantalate Ca_(2)YTaO_(6):Eu^(3+)was synthesized by a solid-state reaction.The purity and surface morphology of the phosphors were characterized.The Ca_(2)YTaO_(6):Eu^(3+)phosphors show a sharp emission peak at 612 nm under near-ultraviolet(n-UV) at 395 nm because of the ^(5)D0→^(7)F_(2) transition of Eu^(3+).The optimal Eu^(3+)doping concentration in Ca_(2)YTaO_(6) is 40 mol% and the critical energy-transfer distance of Eu^(3+)ions was calculated to be 0.9 nm.The emission spectra of Ca_(2)YTaO_(6):Eu_(3+)from 300 to 480 K were investigated.The thermal-quenching temperature(T_(0.5)) of Ca_(2)YTaO_(6):Eu^(3+)is above 480 K.The color purity of Ca_(2)YTaO_(6):40 mol%Eu^(3+)is as high as 99.8%.The luminescence lifetime of Ca_(2)YTaO_(6):40 mol%Eu^(3+)was also discussed.The high color purity and high thermal stability of Eu^(3+)-doped Ca_(2)YTaO_(6) phosphors contribute to its application value in white lightemitting diodes(w-LEDs).
文摘AIM: To compare synchronous laparoscopic cholecystectomy (LC) combined with endoscopic sphincterotomy (EST) and sequential LC combined with EST for treating cholecystocholedocholithiasis. METHODS: A total of 150 patients were included and retrospectively studied. Among these, 70 were selected for the synchronous operation, in which the scheme was endoscopic retrograde cholangiopancreatography combined with EST during LC. The other 80 patients were selected for the sequential operation, in which the scheme involved first cutting the papillary muscle under endoscopy and then performing LC. The indexes in the two groups, including the operation time, the success rate, the incidence of complications, and the length of the hospital stay, were observed.RESULTS: There were no significant differences between the groups in terms of the numbers of patients, sex distribution, age, American Society of Anesthesiologists score, serum bilirubin, γ-glutamyl transpeptidase, mean diameter of common bile duct stones, and previous medical and surgical history (P = 0.54, P = 0.18, P = 0.52, P = 0.22, P = 0.32, P = 0.42, P = 0.68, P = 0.70, P = 0.47 and P = 0.57). There was no significant difference in the surgical operation time between the two groups (112.1 ± 30.8 min vs 104.9 ± 18.2 min). Compared with the sequential operation group, the incidence of pancreatitis was lower (1.4% vs 6.3%), the incidence of hyperamylasemia (1.4% vs 10.0%, P < 0.05) was significantly reduced, and the length of the hospital stay was significantly shortened in the synchronous operation group (3 d vs 4.5 d, P < 0.001). CONCLUSION: For treatment of cholecystocholedo-cholithiasis, synchronous LC combined with EST reduces incidence of complications, decreases length of hospital stay, simplifies the surgical procedure, and reduces operation time.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)the Frontier Science Key Program of the Chinese Academy of Sciences(No.QYZDY-SSW-JSC016)。
文摘In the core of a molten salt fast reactor(MSFR),heavy metal fuel and fission products can be dissolved in a molten fluoride salt to form a eutectic mixture that acts as both fuel and coolant.Fission energy is released from the fuel salt and transferred to the second loop by fuel salt circulation.Therefore,the MSFR is characterized by strong interaction between the neutronics and the thermal hydraulics.Moreover,recirculation flow occurs,and nuclear heat is accumulated near the fertile blanket,which significantly affects both the flow and the temperature fields in the core.In this work,to further optimize the conceptual geometric design of the MSFR,three geometries of the core and fertile blanket are proposed,and the thermal-hydraulic characteristics,including the three-dimensional flow and temperature fields of the fuel and fertile salts,are simulated and analyzed using a coupling scheme between the open source codes OpenMC and OpenFOAM.The numerical results indicate that a flatter core temperature distribution can be obtained and the hot spot and flow stagnation zones that appear in the upper and lower parts of the core center near the reflector can be eliminated by curving both the top and bottom walls of the core.Moreover,eight cooling loops with a total flow rate of0.0555 m3 s-1 ensur an acceptable temperature distribusure an acceptable temperature distribution in the fertile blanket.
基金supported by the National Natural Science Foundation of China(Grants No.51239001,51179015,and 51509023)the Open Research Foundation of the Key Laboratory of the Pearl River Estuarine Dynamics and Associated Process Regulation,the Ministry of Water Resources(Grant No.2018KJ03)+1 种基金the Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province(Grant No.2017SS04)the Key Laboratory of Technology for Safeguarding of Maritime Rights and Interests and Application,State Oceanic Administration(Grant No.SCS1606)
文摘The simulating waves nearshore(SWAN) model has typically been designed for wave simulations in near-shore regions. In this study, the model's applicability to the simulation of typhoon waves in the South China Sea(SCS) was evaluated. A blended wind field, consisting of an interior domain based on Fujita's model and an exterior domain based on Takahashi's model, was used as the driving wind field. The waves driven by Typhoon Kai-tak over the SCS that occurred in 2012 were selected for the numerical simulation research. Sensitivity analyses of time step, grid resolution, and angle resolution were performed in order to obtain optimal model settings. Through sensitivity analyses, it can be found that the time step has a large influence on the results, while grid resolution and angle resolution have a little effect on the results.
基金supported by the National Natural Science Foundation of China(21908116)the Hunan Provincial Natural Science Foundation of China(2019JJ50567)+3 种基金the projects of the Education Department of Hunan Province(17A199)the Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education(LOEC-201809)Scientific Research Foundation of Xiangnan University for High-Level TalentsDevelopment and application of nonferrous metal functional materials team.
文摘Desalination by freezing/thawing method was a very important method to obtain fresh water from seawater.In this work,desalination by freezing/thawing method was conducted with initial sodium chloride of 3.5 wt% in consideration of stirring speed,freezing time and subcooling.The subcooling ranged from 1.2 K to 4 K.The optimum conditions for desalination in this work were stirring speed of 200 r·min^−1,freezing time of 120 min,and subcooling of 3 K.The results also showed that sodiumchloride cannot be effectively removed by once freezing/thawing process.The maximumremoval efficiency of sodiumchloride was 64.3%.Two major reasons resulting in the impurity of obtained melted water by freezing/thawing method were proposed.The first reason was the inevitable adhesion of salt solution to the surface of ice,which could be removed easily by distilled water flushing.The second reason was that salt solution was heterogeneously wrapped in the accumulated ice,which was difficult to be removed by distilled water flushing.The liquid flushing method was proposed to verify the conjecture,and the results were in accordance with the two reasons mentioned above.Additional method,such as multiple flushing liquid method,was suggested to be used during the freezing/thawing process for effectively removing sodium chloride,and obtaining fresh water.
基金Supported by the National Natural Science Foundation of China(61671193)Science and Technology Program of Zhejiang Province(2018C04012,2017C33049)Science and Technology Platform Construction Project of Fujian Science and Technology Department(2015Y2001)
文摘In stroke rehabilitation,rehabilitation equipments can help with the training.But traditional equipments are not convenient to carry,which limits patients to use related rehabilitation techniques.To solve this kind of problem,a new embedded rehabilitation system based on brain computer interface(BCI)is proposed in this paper.The system is based on motor imagery(MI)therapy,in which electroencephalogram(EEG)is evoked by grasping motor imageries of left and right hands,then collected by a wearable device.The EEG is transmitted to a Raspberry Pie processing unit through Bluetooth and decoded as the instructions to control the equipment extension.Users experience the limb movement through the visual feedback so as to achieve active rehabilitation.A pilot study shows that the user can control the movement of the rehabilitation equipment through his mind,and the equipment is convenient to carry.The study provides a new way to stroke rehabilitation.
基金Project supported by Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications(2019XGJSKFJJ01)the Construction Program of the key discipline in Hunan Province+4 种基金the Projects of the Education Department of Hunan Province(18A465)Science and Technology Plan Project of Chenzhou City(jsyf2017014)Natural Science Foundation of Shandong Province(ZR2018LB002)Key Research and Development Project of Shandong Province(2019GGX102081)Key Research and Development Project of Jining(2019ZDGH026)。
文摘Cyan-emitting Ca_(9)NaGd_(2/3)(PO_(4))_(7):Eu^(2+)phosphors were synthesized via high temperature solid-state route.X-ray powder diffraction(XRD)and scanning electron microscopy(SEM)were used to verify the phase and morphology of the Ca_(9)NaGd_(2/3)(PO_(4))_(7):Eu^(2+)(CNGP:Eu^(2+))phosphors.The as-obtained phosphor exhibits a broad excitation band of 250-420 nm,which is near the ultraviolet region.An intense asymmetric cyan emission at 496 nm corresponds to the 5 d-4 f transition of Eu^(2+).The multiplesite luminescent properties of Eu^(2+)ions in CNGP benefit from versatile structure ofβ-Ca3(PO4)2 compounds.The effective energy transfer distance is 5.46 nm(through the spectral overlap calculation),validating that the resonant energy migration type is via dipole-dipole interaction mechanism.Compared to the initial one at room temperature,the luminescent intensity of CNGP:Eu^(2+)phosphor can maintain 77%as it is heated up to 420 K.A white light-emitting diode(WLED)with excellent luminesce nt properties was successfully fabricated.Moreover,the CIE chromaticity coordinates of fabricated WLED driven by changing current just change slightly.
基金Project supported by the Natural Science Foundation of Shaanxi Province(2018JM5055)Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications(2019XGJSKFJJ01)+2 种基金the Construction Program of the Key Discipline in Hunan Provincethe Projects of the Education Department of Hunan Province(18A465)Science and Technology Plan Project of Chenzhou City(jsyf2017014)。
文摘Novel yellow-emitting phosphors of Dy^(3+)-doped double perovskite Ca_(2)MgTeO_(6) were synthesized by using a conventional high-temperature solid-state reaction.The phase purity,particle morphology,size distribution,elemental composition,luminescence properties,and luminescence decay curves of the resulting products were then analyzed in detail.The Ca_(2)MgTeO_(6):Dy^(3+),Na^(+) phosphors show three emission peaks after near-ultraviolet excitation at 350 nm,which correspond to ^(4)F_(9/2)→^(6)H_(11/2),^(4)F_(9/2)→^(6)H_(13/2),and ^(4)F_(9/2)→^(6)H_(13/2) transitions,respectively.Among them,the strongest peak is observed at 573 nm.The best doping content of Dy^(3+)in Ca_(2)MgTeO_(6):xDy^(3+),xNa^(+) phosphors is x=5 mol%.The calculated critical distance of energy transfer between Dy^(3+) ions is 1.6 nm.Luminescence quenching is confirmed to be due to dipole-dipole interactions among Dy^(3+) ions.The phosphors show excellent thermal stability with high activation energy(0.27 eV).The Commission Internationale de l’Eclairage(CIE) chromaticity coordinates of the Ca_(2)MgTeO_(6) Dy^(3+),Na^(+) phosphors are located in the yellow region.White light-emitting diodes(w-LEDs) were fabricated with a high color rendering index(R_(a)) of 88 and a good correlated color temperature(CCT) of 5440 K.All observed properties indicate that Ca_(2)MgTeO_(6):Dy^(3+),Na^(+) phosphors have potential applications in display and photonic devices.
