Based on the Cahn-Hilliard phase field model, a three-dimensional multiple-field coupling model for simulating the motion characteristics of a rising bubble in a liquid is established in a gas-liquid two-phase flow. T...Based on the Cahn-Hilliard phase field model, a three-dimensional multiple-field coupling model for simulating the motion characteristics of a rising bubble in a liquid is established in a gas-liquid two-phase flow. The gas-liquid interface motion is simulated by using a phase-field method, and the effect of the electric field intensity on bubble dynamics is studied without electric field, or with vertical electric field or horizontal electric field. Through the coupling effect of electric field and flow field, the deformation of a single rising bubble and the formation of wake vortices under the action of gravity and electric field force are studied in detail. The correctness of the results is verified by mass conservation, and the influences of different electric field directions and different voltages on the movement of bubbles in liquid are considered. The results show that the ratio of the length to axis is proportional to the strength of the electric field when the air bubble is stretched into an ellipsoid along the electric field line under the action of electrostatic gravity and surface tension. In addition, the bubble rising speed is affected by the electric field, the vertical electric field accelerates the bubble rise, and the horizontal direction slows it down.展开更多
By coupling the phase field model with the continuity equation of incompressible fluid, Navier–Stokes equation,electric field equation, and other governing equations, a multi-field coupling model for multi-bubble coa...By coupling the phase field model with the continuity equation of incompressible fluid, Navier–Stokes equation,electric field equation, and other governing equations, a multi-field coupling model for multi-bubble coalescence in a viscous fluids is established. The phase field method is used to capture the two-phase interface. The motion and coalescence of a pair of coaxial bubbles under an external uniform electric field and the effects of different electric field strengths on the interaction and coalescence of rising bubbles are studied. The results show that the uniform electric field accelerates the collision and coalescence process of double bubbles in the fluid, and increases the rising velocity of the coalesced bubble.The electric field with an intensity of E = 2 kV/mm is reduced about 2 times compared with that without electric field in coalescence time. When the electric field strength is strong(E ≥ 1 kV/mm), the coalesced bubble will rupture before it rises to the top of the calculation area, and the time of the bubble rupturing also decreases with the increase of the electric field strength. The phase field method is compared with the simulation results of Lattice Boltzmann Method(LBM), and the shape of bubble obtained by the two methods is in good agreement, which verifies the correctness of the calculation model.展开更多
The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the...The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the studies the alkali metals were treated as dopants. Several recent studies have showed that the alkali metals may not only act as dopants but also form secondary phases in the absorber layer or on the surfaces of the films. Using the first-principles calculations, we screened out the most probable secondary phases of Na and K in CIGS and CZTSSe, and studied their electronic structures and optical properties. We found that all these alkali chalcogenide compounds have larger band gaps and lower VBM levels than CIGS and CZTSSe, because the existence of strong p-d coupling in CIS and CZTS pushes the valence band maximum （VBM） level up and reduces the band-gaps, while there is no such p-d coupling in these alkali chalcogenides. This band alignment repels the photo-generated holes from the secondary phases and prevents the electron-hole recombination. Moreover, the study on the optical properties of the secondary phases showed that the absorption coefficients of these alkali chalcogenides are much lower than those of CIGS and CZTSSe in the energy range of 0-3.4eV, which means that the alkali chalcogenides may not influence the absorption of solar light. Since the alkali metal dopants can passivate the grain boundaries and increase the hole carrier concentration, and meanwhile their related secondary phases have innocuous effect on the optical absorption and band alignment, we can understand why the alkali metal dopants can improve the CIGS and CZTSSe solar cell performance.展开更多
A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate, carbonate, hydroxide and oxalate etc. CaO samples were found to be effec...A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate, carbonate, hydroxide and oxalate etc. CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile. To determine the influence of the physicochemical properties and surface basicity on the catalytic activity, the prepared CaO samples were characterized using thermogravimetry （TG）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, N2-adsorption and temperature-programmed desorption of CO2 （CO2-TPD）. The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance. In contrast, the surface area, porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity. CaO sample, obtained by the decomposition of Ca（OH）2, prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution, exhibits the highest amount of very strong basic sites and stronger strength of basic sites, and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples. Under the selected reaction conditions, the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.展开更多
Dual-energy X-ray absorptiometry provides two modes of head computed tomography （CT） angiography scanning： neuro-digital subtraction angiography and dual-energy CT angiography （DE-CTA）. Previous studies have comp...Dual-energy X-ray absorptiometry provides two modes of head computed tomography （CT） angiography scanning： neuro-digital subtraction angiography and dual-energy CT angiography （DE-CTA）. Previous studies have compared image quality, radiation exposure, and bone removal between neuro-digital subtraction angiography and DE-CTA. However, the number of cases was relatively small. The present study examined 300 suspected cases of cerebrovascular disease and observed the methods and duration of post-processing, examination time, and data volume. Results demonstrated similar image quality between the two methods, but lower radiation doses and shorter examination time in DE-CTA. DE-CTA allowed for faster and more stable scanning performance and post-processing methods, facilitating accurate and direct diagnosis of cerebrovascular disease.展开更多
The synergistic effect of total ionizing dose(TID) and single event gate rupture(SEGR) in SiC power metal–oxide–semiconductor field effect transistors(MOSFETs) is investigated via simulation. The device is found to ...The synergistic effect of total ionizing dose(TID) and single event gate rupture(SEGR) in SiC power metal–oxide–semiconductor field effect transistors(MOSFETs) is investigated via simulation. The device is found to be more sensitive to SEGR with TID increasing, especially at higher temperature. The microscopic mechanism is revealed to be the increased trapped charges induced by TID and subsequent enhancement of electric field intensity inside the oxide layer.展开更多
YAG (Y_(3)Al_(5)O_(12)) transparent ceramics have attractive application prospects for transparent armor protection modules because of their excellent light transmittance and anti-ballistic capability. Understanding t...YAG (Y_(3)Al_(5)O_(12)) transparent ceramics have attractive application prospects for transparent armor protection modules because of their excellent light transmittance and anti-ballistic capability. Understanding the fracture behavior and damage mechanism of YAG is necessary for armor design. To explore the damage characteristics of YAG under compression and tension, shock compression and shockless spalling experiments with soft recovery technique are conducted. The spall strength of YAG is obtained and the recovered samples are observed by CT and SEM. It is shown that the macroscopic damage characteristic of YAG under compression is vertical split cracks with oblique fine cracks distributed in the entire sample, while that under tension is horizontal transgranular cracks concentrated near the main spall surface. The cracks generated by macroscopic compression, tension and shear stress extend in similar tensile form at the microscale. The proportion of transgranular fractures on spall surfaces is higher than that of cracks induced by macroscopic compression. Meanwhile, higher loading rate and longer loading duration increase the transgranular fracture percentage.展开更多
The results of a commissioning experiment on the SILEX-Ⅱlaser facility(formerly known as CAEP-PW)are reported.SILEX-Ⅱis a complete optical parametric chirped-pulse amplification laser facility.The peak power reached...The results of a commissioning experiment on the SILEX-Ⅱlaser facility(formerly known as CAEP-PW)are reported.SILEX-Ⅱis a complete optical parametric chirped-pulse amplification laser facility.The peak power reached about 1 PWin a 30 fs pulse duration during the experiment.The laser contrast was better than 1010 at 20 ps ahead of the main pulse.In the basic laser foil target interaction,a set of experimental data were collected,including spatially resolved x-ray emission,the image of the coherent transition radiation,the harmonic spectra in the direction of reflection,the energy spectra and beam profile of accelerated protons,hot-electron spectra,and transmitted laser energy fraction and spatial distribution.The experimental results show that the laser intensity reached 531020 W/cm^(2) within a 5.8μm focus(FWHM).Significant laser transmission did not occur when the thickness of theCHfoil was equal to or greater than 50 nm.The maximum energy of the accelerated protons in the target normal direction was roughly unchanged when the target thickness varied between 50 nm and 15μm.The maximum proton energy via the target normal sheath field acceleration mechanism was about 21 MeV.We expect the on-target laser intensity to reach 10^(22) W/cm^(2) in the near future,after optimization of the laser focus and upgrade of the laser power to 3 PW.展开更多
Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of meth...Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97×10^3-632.91×10^3 cells/g （in dry basis） in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium （NMS）. The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.展开更多
As an emerging 2D conjugated material,graphitic carbon nitride(CN) has attracted great research attention as important catalytic medium for transforming solar energy.Nanostructure modulation of CN is an effective way ...As an emerging 2D conjugated material,graphitic carbon nitride(CN) has attracted great research attention as important catalytic medium for transforming solar energy.Nanostructure modulation of CN is an effective way to improve catalytic activities and has been extensively investigated,but remains challenging due to complex processes,time consuming or low yield.Here,taking advantage of recent discovered good solvents for CN,a nanoprecipitation approach using poor solvents is proposed for preparation of CN nanoparticles(CN NPs).With simple processes of CN dissolution and precipitation,we can quickly synthesize CN NPs(^40 nm) with a yield of up to 50%,the highest one to the best of our knowledge.As an example of potential applications,the as-prepared CN NPs were applied to photocatalytic degradation of dyes with an evident boosted performance up to 2.5 times.This work would open a new way for batch preparation of nanostructured CN and pave its large-scale industrial applications.展开更多
In advanced hepatocellular carcinoma(HCC)tissues,M2-like tumor-associated macrophages(TAMs)are in the majority and promotes HCC progression.Contrary to the pro-tumor effect of M2-like TAMs,M1-like TAMs account for a s...In advanced hepatocellular carcinoma(HCC)tissues,M2-like tumor-associated macrophages(TAMs)are in the majority and promotes HCC progression.Contrary to the pro-tumor effect of M2-like TAMs,M1-like TAMs account for a small proportion and have anti-tumor effects.Since TAMs can switch from one type to another,reprogramming TAMs may be an important treatment for HCC therapy.However,the mechanisms of phenotypic switch and reprogramming TAMs are still obscure.In this study,we analyzed differential genes in normal macrophages and TAMs,and found that loss of MANF in TAMs accompanied by high levels of downstream genes negatively regulated by MANF.MANF reprogrammed TAMs into M1 phenotype.Meanwhile,loss of MANF promoted HCC progression in HCC patients and mice HCC model,especially tumor neovascularization.Additionally,macrophages with MANF supplement suppressed HCC progression in mice,suggesting MANF supplement in macrophage was an effective treatment for HCC.Mechanistically,MANF enhanced the HSF1-HSP70-1 interaction,restricted HSF1 in the cytoplasm of macrophages,and decreased both mRNA and protein levels of HSP70-1,which in turn led to reprogramming TAMs,and suppressing neovascularization of HCC.Our study contributes to the exploration the mechanism of TAMs reprogramming,which may provide insights for future therapeutic exploitation of HCC neovascularization.展开更多
Background:The mechanisms underlying cardiac remodeling in aortic valvular(AoV)disease remain poorly understood,partially due to the insufficiency of appropriate preclinical animal models.Here,we present a novel murin...Background:The mechanisms underlying cardiac remodeling in aortic valvular(AoV)disease remain poorly understood,partially due to the insufficiency of appropriate preclinical animal models.Here,we present a novel murine model of aortic regurgitation(AR)generated by transapical wire destruction of the AoV.Methods:Directed by echocardiography,apical puncture of the left ventricle(LV)was performed in adult male C57BL/6 mice,and a metal guidewire was used to induce AoV destruction.Echocardiography,invasive LV hemodynamic and histological examination were conducted to assess the degree of AR,LV function and remodeling.Results:AR mice exhibited rapid aortic regurgitation velocity(424±15.22 mm/s)immediately following successful surgery.Four weeks post-surgery,echocardiography revealed a 54.6%increase in LV diastolic diameter and a 55.1%decrease in LV ejection fraction in AR mice compared to sham mice.Pressure-volume catheterization indicated that AR mice had significantly larger LV end-diastolic volumes(66.2±1.5μL vs.41.8±3.4μL),reduced LV contractility(lower dP/dt max and Ees),and diminished LV compliance(smaller dP/dt min and longer Tau)compared to sham mice.Histological examination demonstrated that AR mice had significantly larger cardiomyocyte area and more myocardial fibrosis in LV tissue,as well as a 107%and a 122%increase of heart weight/tibial length and lung weight/tibial length,respectively,relative to sham mice.Conclusions:The trans-apex wire-induced destruction of the AoV establishes a novel and efficient murine model to develop AR,characterized by significant eccentric LV hypertrophy,heart failure,and pulmonary congestion.展开更多
In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with ...In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with the catalysis of polyols.The gas sensor gained excellent sensitivity to NO_(2) at a concentration range of 200 ppm to 100 ppb,benefiting from the loading of Pt nanoparticles,and exhibited a short response time(22 s)and recovery time(170 s)to 100 ppm of NO_(2) at room temperature with excellent selectivity to NO_(2) compared with other gases.This phenomenon was attributed to the spillover effect and the synergic electronic interaction with semiconductor materials of Pt,which not only provided more electrons for the adsorption of NO_(2) molecules but also occupied effective sites,causing poor sites for other gases.The low detection limit of Pt/NP-GaN was 100 ppb,and the gas sensor still had a fast response 70 d after fabrication.Besides,the gas-sensing mechanism of the gas sensor was further elaborated to determine the reason leading to its improved properties.The significant spillover impact and oxygen dissociation of Pt provided advantages to its synergic electronic interaction with semiconductor materials,leading to the improvement of the gas properties of gas sensors.展开更多
MicroRNAs(miRNAs)function as important regulators in the immune response and inflammation.Several approaches have been reported to computationally predict miRNAs and their potential targets.However,there are still man...MicroRNAs(miRNAs)function as important regulators in the immune response and inflammation.Several approaches have been reported to computationally predict miRNAs and their potential targets.However,there are still many miRNA–target interactions that are unpredictable by using the current computational algorithms.We established a miRNA in vivo precipitation method(miRIP)to identify unpredictable miRNAs with definite targets in these cells.Because Stat3 is a well-known transcription factor involved in innate immunity and inflammation,we utilized the miRIP method to identify miRNAs that bind Stat3 mRNA in macrophages.Among the captured miRNAs,miR-151-3p was confirmed to interact with Stat3 mRNA 3′-UTR and downregulate the Stat3 protein levels.LPS stimulation decreased miR-151-3p expression,thereby increasing IL-6 production.Therefore,we found that miR-151-3p inhibited LPS-induced IL-6 production by targeting Stat3.These data further confirmed miRIP as an efficient method to identify unpredictable miRNAs and explore miRNAs-mediated regulation in innate immunity and inflammation.展开更多
We evaluated and compared the diagnostic accuracy(DA) of apparent diffusion coefficient(ADC) values with that of lesion-to-liver ADC ratios in the characterization of solid focal liver lesions(FLLs).This prospective s...We evaluated and compared the diagnostic accuracy(DA) of apparent diffusion coefficient(ADC) values with that of lesion-to-liver ADC ratios in the characterization of solid focal liver lesions(FLLs).This prospective study was approved by the Institutional Human Ethics Board,after waiving written informed consent.Diffusion-weighted imaging and other routine magnetic resonance imaging were performed on 142 consecutive patients with suspected liver disease.The mean ADC values and lesion-to-liver ADC ratios were compared between benign and malignant solid FLLs.Receiver operating characteristic analysis was performed.The study participants included 46 patients(28 men,18 women;mean age,52.5 years) with 57 solid FLLs(32 malignant and 25 benign FLLs).The mean ADC values and ADC ratios of benign solid FLLs were significantly higher than those of malignant lesions(P<0.01).The difference between the area under the receiver operating characteristic curve of the ADC values(0.699) and ADC ratios(0.752) was not significant.Our study suggests that the DA of the ADC ratio is not significantly higher than that of ADC in characterizing solid FLLs.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51661020,11504149,and 11364024)the Postdoctoral Science Foundation of China(Grant No.2014M560371)the Funds for Distinguished Young Scientists of Lanzhou University of Technology,China(Grant No.J201304)
文摘Based on the Cahn-Hilliard phase field model, a three-dimensional multiple-field coupling model for simulating the motion characteristics of a rising bubble in a liquid is established in a gas-liquid two-phase flow. The gas-liquid interface motion is simulated by using a phase-field method, and the effect of the electric field intensity on bubble dynamics is studied without electric field, or with vertical electric field or horizontal electric field. Through the coupling effect of electric field and flow field, the deformation of a single rising bubble and the formation of wake vortices under the action of gravity and electric field force are studied in detail. The correctness of the results is verified by mass conservation, and the influences of different electric field directions and different voltages on the movement of bubbles in liquid are considered. The results show that the ratio of the length to axis is proportional to the strength of the electric field when the air bubble is stretched into an ellipsoid along the electric field line under the action of electrostatic gravity and surface tension. In addition, the bubble rising speed is affected by the electric field, the vertical electric field accelerates the bubble rise, and the horizontal direction slows it down.
基金supported by the National Natural Science Foundation of China(Grant Nos.51661020,11504149,and 11364024)the Postdoctoral Science Foundation of China(Grant No.2014M560371)the Funds for Distinguished Young Scientists of Lanzhou University of Technology,China(Grant No.J201304)
文摘By coupling the phase field model with the continuity equation of incompressible fluid, Navier–Stokes equation,electric field equation, and other governing equations, a multi-field coupling model for multi-bubble coalescence in a viscous fluids is established. The phase field method is used to capture the two-phase interface. The motion and coalescence of a pair of coaxial bubbles under an external uniform electric field and the effects of different electric field strengths on the interaction and coalescence of rising bubbles are studied. The results show that the uniform electric field accelerates the collision and coalescence process of double bubbles in the fluid, and increases the rising velocity of the coalesced bubble.The electric field with an intensity of E = 2 kV/mm is reduced about 2 times compared with that without electric field in coalescence time. When the electric field strength is strong(E ≥ 1 kV/mm), the coalesced bubble will rupture before it rises to the top of the calculation area, and the time of the bubble rupturing also decreases with the increase of the electric field strength. The phase field method is compared with the simulation results of Lattice Boltzmann Method(LBM), and the shape of bubble obtained by the two methods is in good agreement, which verifies the correctness of the calculation model.
基金supported by the National Natural Science Foundation of China(NSFC)under grant nos.61574059 and 61722402the National Key Research and Development Program of China(2016YFB0700700)+1 种基金Shu-Guang program(15SG20)CC of ECNU
文摘The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the studies the alkali metals were treated as dopants. Several recent studies have showed that the alkali metals may not only act as dopants but also form secondary phases in the absorber layer or on the surfaces of the films. Using the first-principles calculations, we screened out the most probable secondary phases of Na and K in CIGS and CZTSSe, and studied their electronic structures and optical properties. We found that all these alkali chalcogenide compounds have larger band gaps and lower VBM levels than CIGS and CZTSSe, because the existence of strong p-d coupling in CIS and CZTS pushes the valence band maximum （VBM） level up and reduces the band-gaps, while there is no such p-d coupling in these alkali chalcogenides. This band alignment repels the photo-generated holes from the secondary phases and prevents the electron-hole recombination. Moreover, the study on the optical properties of the secondary phases showed that the absorption coefficients of these alkali chalcogenides are much lower than those of CIGS and CZTSSe in the energy range of 0-3.4eV, which means that the alkali chalcogenides may not influence the absorption of solar light. Since the alkali metal dopants can passivate the grain boundaries and increase the hole carrier concentration, and meanwhile their related secondary phases have innocuous effect on the optical absorption and band alignment, we can understand why the alkali metal dopants can improve the CIGS and CZTSSe solar cell performance.
基金supported by the National Natural Science Foundation of China (No.21173110)
文摘A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate, carbonate, hydroxide and oxalate etc. CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile. To determine the influence of the physicochemical properties and surface basicity on the catalytic activity, the prepared CaO samples were characterized using thermogravimetry （TG）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, N2-adsorption and temperature-programmed desorption of CO2 （CO2-TPD）. The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance. In contrast, the surface area, porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity. CaO sample, obtained by the decomposition of Ca（OH）2, prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution, exhibits the highest amount of very strong basic sites and stronger strength of basic sites, and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples. Under the selected reaction conditions, the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.
文摘Dual-energy X-ray absorptiometry provides two modes of head computed tomography （CT） angiography scanning： neuro-digital subtraction angiography and dual-energy CT angiography （DE-CTA）. Previous studies have compared image quality, radiation exposure, and bone removal between neuro-digital subtraction angiography and DE-CTA. However, the number of cases was relatively small. The present study examined 300 suspected cases of cerebrovascular disease and observed the methods and duration of post-processing, examination time, and data volume. Results demonstrated similar image quality between the two methods, but lower radiation doses and shorter examination time in DE-CTA. DE-CTA allowed for faster and more stable scanning performance and post-processing methods, facilitating accurate and direct diagnosis of cerebrovascular disease.
基金Project supported by the National Natural Science Foundation of China(Grant No.12004329)Open Project of State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(Grant No.SKLIPR2115)+1 种基金Postgraduate Research and Practice Innovation Program of Jiangsu Province(Grant No.SJCX22_1704)Innovative Science and Technology Platform Project of Cooperation between Yangzhou City and Yangzhou University,China(Grant Nos.YZ202026301 and YZ202026306)。
文摘The synergistic effect of total ionizing dose(TID) and single event gate rupture(SEGR) in SiC power metal–oxide–semiconductor field effect transistors(MOSFETs) is investigated via simulation. The device is found to be more sensitive to SEGR with TID increasing, especially at higher temperature. The microscopic mechanism is revealed to be the increased trapped charges induced by TID and subsequent enhancement of electric field intensity inside the oxide layer.
基金This work is funded by the National Natural Science Foundation of China(No.11772159)the NSAF Joint Fund(No.U1730101)the Fundamental Research Funds for the Central Universities(No.30917011104).
文摘YAG (Y_(3)Al_(5)O_(12)) transparent ceramics have attractive application prospects for transparent armor protection modules because of their excellent light transmittance and anti-ballistic capability. Understanding the fracture behavior and damage mechanism of YAG is necessary for armor design. To explore the damage characteristics of YAG under compression and tension, shock compression and shockless spalling experiments with soft recovery technique are conducted. The spall strength of YAG is obtained and the recovered samples are observed by CT and SEM. It is shown that the macroscopic damage characteristic of YAG under compression is vertical split cracks with oblique fine cracks distributed in the entire sample, while that under tension is horizontal transgranular cracks concentrated near the main spall surface. The cracks generated by macroscopic compression, tension and shear stress extend in similar tensile form at the microscale. The proportion of transgranular fractures on spall surfaces is higher than that of cracks induced by macroscopic compression. Meanwhile, higher loading rate and longer loading duration increase the transgranular fracture percentage.
基金This work was supported by the National Key Program for S&T Research and Development(Grant No.2018YFA0404804)the Science Challenge Project(Grant No.TZ2016005)the National Natural Science Foundation of China(Grant No.11805181).
文摘The results of a commissioning experiment on the SILEX-Ⅱlaser facility(formerly known as CAEP-PW)are reported.SILEX-Ⅱis a complete optical parametric chirped-pulse amplification laser facility.The peak power reached about 1 PWin a 30 fs pulse duration during the experiment.The laser contrast was better than 1010 at 20 ps ahead of the main pulse.In the basic laser foil target interaction,a set of experimental data were collected,including spatially resolved x-ray emission,the image of the coherent transition radiation,the harmonic spectra in the direction of reflection,the energy spectra and beam profile of accelerated protons,hot-electron spectra,and transmitted laser energy fraction and spatial distribution.The experimental results show that the laser intensity reached 531020 W/cm^(2) within a 5.8μm focus(FWHM).Significant laser transmission did not occur when the thickness of theCHfoil was equal to or greater than 50 nm.The maximum energy of the accelerated protons in the target normal direction was roughly unchanged when the target thickness varied between 50 nm and 15μm.The maximum proton energy via the target normal sheath field acceleration mechanism was about 21 MeV.We expect the on-target laser intensity to reach 10^(22) W/cm^(2) in the near future,after optimization of the laser focus and upgrade of the laser power to 3 PW.
基金supported by the Hi-Tech Research and Development Program (863) of China (No. 2007AA06Z349)the Science and Technology Commission of Shanghai Municipality (No. 09DZ2251700)
文摘Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97×10^3-632.91×10^3 cells/g （in dry basis） in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium （NMS）. The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.
基金financially supported in part by the National Natural Science Foundation of China(Nos.21775018,21675022)the Natural Science Foundation of Jiangsu Province(Nos.BK20160028,BK20170084)+1 种基金the Open Funds of the State Key Laboratory of Electroanalytical Chemistry(No.SKLEAC201909)the Fundamental Research Funds for the Central Universities。
文摘As an emerging 2D conjugated material,graphitic carbon nitride(CN) has attracted great research attention as important catalytic medium for transforming solar energy.Nanostructure modulation of CN is an effective way to improve catalytic activities and has been extensively investigated,but remains challenging due to complex processes,time consuming or low yield.Here,taking advantage of recent discovered good solvents for CN,a nanoprecipitation approach using poor solvents is proposed for preparation of CN nanoparticles(CN NPs).With simple processes of CN dissolution and precipitation,we can quickly synthesize CN NPs(^40 nm) with a yield of up to 50%,the highest one to the best of our knowledge.As an example of potential applications,the as-prepared CN NPs were applied to photocatalytic degradation of dyes with an evident boosted performance up to 2.5 times.This work would open a new way for batch preparation of nanostructured CN and pave its large-scale industrial applications.
基金funded by support programs for Jun Liu,including the National Natural Science Foundation of China(82073862)Excellent Youth Talent Program of Anhui Province Natural Science Foundation(2108085Y27,China)funded by Anhui Province Natural Science Foundation(2208085MH284,China)for Xiangpeng Hu,and funded by the National Natural Science Foundation of China(U21A20345)for Yuxian Shen。
文摘In advanced hepatocellular carcinoma(HCC)tissues,M2-like tumor-associated macrophages(TAMs)are in the majority and promotes HCC progression.Contrary to the pro-tumor effect of M2-like TAMs,M1-like TAMs account for a small proportion and have anti-tumor effects.Since TAMs can switch from one type to another,reprogramming TAMs may be an important treatment for HCC therapy.However,the mechanisms of phenotypic switch and reprogramming TAMs are still obscure.In this study,we analyzed differential genes in normal macrophages and TAMs,and found that loss of MANF in TAMs accompanied by high levels of downstream genes negatively regulated by MANF.MANF reprogrammed TAMs into M1 phenotype.Meanwhile,loss of MANF promoted HCC progression in HCC patients and mice HCC model,especially tumor neovascularization.Additionally,macrophages with MANF supplement suppressed HCC progression in mice,suggesting MANF supplement in macrophage was an effective treatment for HCC.Mechanistically,MANF enhanced the HSF1-HSP70-1 interaction,restricted HSF1 in the cytoplasm of macrophages,and decreased both mRNA and protein levels of HSP70-1,which in turn led to reprogramming TAMs,and suppressing neovascularization of HCC.Our study contributes to the exploration the mechanism of TAMs reprogramming,which may provide insights for future therapeutic exploitation of HCC neovascularization.
基金Natural Science Foundation of Guangdong Province,Grant/Award Number:2023A1515110032 and 2022A1515220152Guangzhou Key Research and Development Program Foundation,Grant/Award Number:202206010199National Natural Science Foundation of China,Grant/Award Number:82100407,82272602 and 82370242。
文摘Background:The mechanisms underlying cardiac remodeling in aortic valvular(AoV)disease remain poorly understood,partially due to the insufficiency of appropriate preclinical animal models.Here,we present a novel murine model of aortic regurgitation(AR)generated by transapical wire destruction of the AoV.Methods:Directed by echocardiography,apical puncture of the left ventricle(LV)was performed in adult male C57BL/6 mice,and a metal guidewire was used to induce AoV destruction.Echocardiography,invasive LV hemodynamic and histological examination were conducted to assess the degree of AR,LV function and remodeling.Results:AR mice exhibited rapid aortic regurgitation velocity(424±15.22 mm/s)immediately following successful surgery.Four weeks post-surgery,echocardiography revealed a 54.6%increase in LV diastolic diameter and a 55.1%decrease in LV ejection fraction in AR mice compared to sham mice.Pressure-volume catheterization indicated that AR mice had significantly larger LV end-diastolic volumes(66.2±1.5μL vs.41.8±3.4μL),reduced LV contractility(lower dP/dt max and Ees),and diminished LV compliance(smaller dP/dt min and longer Tau)compared to sham mice.Histological examination demonstrated that AR mice had significantly larger cardiomyocyte area and more myocardial fibrosis in LV tissue,as well as a 107%and a 122%increase of heart weight/tibial length and lung weight/tibial length,respectively,relative to sham mice.Conclusions:The trans-apex wire-induced destruction of the AoV establishes a novel and efficient murine model to develop AR,characterized by significant eccentric LV hypertrophy,heart failure,and pulmonary congestion.
基金supported by the National Natural Science Foundation of China(Nos.62031022 and 52375572)the Key R&D Program of Shanxi Province,China(No.202102030201003)+1 种基金Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,China(No.2022SXAT001)Key Core Technological Breakthrough Program of Taiyuan City,China(No.2024TYJB0126).
文摘In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with the catalysis of polyols.The gas sensor gained excellent sensitivity to NO_(2) at a concentration range of 200 ppm to 100 ppb,benefiting from the loading of Pt nanoparticles,and exhibited a short response time(22 s)and recovery time(170 s)to 100 ppm of NO_(2) at room temperature with excellent selectivity to NO_(2) compared with other gases.This phenomenon was attributed to the spillover effect and the synergic electronic interaction with semiconductor materials of Pt,which not only provided more electrons for the adsorption of NO_(2) molecules but also occupied effective sites,causing poor sites for other gases.The low detection limit of Pt/NP-GaN was 100 ppb,and the gas sensor still had a fast response 70 d after fabrication.Besides,the gas-sensing mechanism of the gas sensor was further elaborated to determine the reason leading to its improved properties.The significant spillover impact and oxygen dissociation of Pt provided advantages to its synergic electronic interaction with semiconductor materials,leading to the improvement of the gas properties of gas sensors.
基金We thank Dr Taoyong Chen and Dr Mingjin Yang for helpful discussion and Ms Mei Jin for technical assistanceThis work was supported by Grants from the National Key Basic Research Program of China(2013CB530502,2015CB964403)+1 种基金the National Natural Science Foundation of China(31470849,31390431 and 81471569)the Shanghai Committee of Science and Technology(2015QA1404700).
文摘MicroRNAs(miRNAs)function as important regulators in the immune response and inflammation.Several approaches have been reported to computationally predict miRNAs and their potential targets.However,there are still many miRNA–target interactions that are unpredictable by using the current computational algorithms.We established a miRNA in vivo precipitation method(miRIP)to identify unpredictable miRNAs with definite targets in these cells.Because Stat3 is a well-known transcription factor involved in innate immunity and inflammation,we utilized the miRIP method to identify miRNAs that bind Stat3 mRNA in macrophages.Among the captured miRNAs,miR-151-3p was confirmed to interact with Stat3 mRNA 3′-UTR and downregulate the Stat3 protein levels.LPS stimulation decreased miR-151-3p expression,thereby increasing IL-6 production.Therefore,we found that miR-151-3p inhibited LPS-induced IL-6 production by targeting Stat3.These data further confirmed miRIP as an efficient method to identify unpredictable miRNAs and explore miRNAs-mediated regulation in innate immunity and inflammation.
基金supported by Beijing Municipal Science&Technology Commission(D101100050010056)National Key Technology R&D Program(20I5BAI13B09)
文摘We evaluated and compared the diagnostic accuracy(DA) of apparent diffusion coefficient(ADC) values with that of lesion-to-liver ADC ratios in the characterization of solid focal liver lesions(FLLs).This prospective study was approved by the Institutional Human Ethics Board,after waiving written informed consent.Diffusion-weighted imaging and other routine magnetic resonance imaging were performed on 142 consecutive patients with suspected liver disease.The mean ADC values and lesion-to-liver ADC ratios were compared between benign and malignant solid FLLs.Receiver operating characteristic analysis was performed.The study participants included 46 patients(28 men,18 women;mean age,52.5 years) with 57 solid FLLs(32 malignant and 25 benign FLLs).The mean ADC values and ADC ratios of benign solid FLLs were significantly higher than those of malignant lesions(P<0.01).The difference between the area under the receiver operating characteristic curve of the ADC values(0.699) and ADC ratios(0.752) was not significant.Our study suggests that the DA of the ADC ratio is not significantly higher than that of ADC in characterizing solid FLLs.
