The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF...The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.展开更多
The dynamic effective shear strength of saturated sand under cyclic loading is discussed in this paper.The discussion includes the transient time depen- dency behaviors based on the analysis of the results obtained in...The dynamic effective shear strength of saturated sand under cyclic loading is discussed in this paper.The discussion includes the transient time depen- dency behaviors based on the analysis of the results obtained in conventional cyclic triaxial tests and cyclic torsional shear triaxial tests.It has been found that the dy- namic effective shear strength is composed of effective frictional resistance and viscous resistance,which are characterized by the strain rate dependent feature of strength magnitude,the coupling of consolidation stress with cyclic stress and the dependency of time needed to make the soil strength sufficiently mobilized,and can also be ex- pressed by the extended Mohr-Coulomb's law.The two strength parameters of the dynamic effective internal frictional angle φd and the dynamic viscosity coefficient η are determined.The former is unvaried for different number of cyclic loading,dy- namic stress form and consolidation stress ratio.And the later is unvaried for the different dynamic shear strain rate γt developed during the sand liquefaction,but increases with the increase of initial density of sand.The generalization of dynamic effective stress strength criterion in the 3-dimensional effective stress space is studied in detail for the purpose of its practical use.展开更多
The effects of three different typical resistivity models（Spitzer, Z＆L and M＆G） on the performance of pulsed inductive acceleration plasma are studied. Numerical results show that their influences decrease with th...The effects of three different typical resistivity models（Spitzer, Z＆L and M＆G） on the performance of pulsed inductive acceleration plasma are studied. Numerical results show that their influences decrease with the increase of the plasma temperature. The significant discriminations among them appear at the plasma temperature lower than 2.5 eV, and the maximum gap of the pulsed inductive plasma accelerated efficiency is approximately 2.5%.Moreover, the pulsed inductive plasma accelerated efficiency is absolutely related to the dynamic impedance parameters, such as voltage, inductance, capacitance and flow rate. However, the distribution of the efficiency as a function of plasma temperature with three resistivity models has nothing to do with the dynamic impedance parameter.展开更多
Residual electrical resistivity due to short-range order has been calculated for Cu100-xAlx (x=9.13,13.56, 14.5 and 14.76 in at pct) alloys using pseudopotential approach, and the results have been discussed in the li...Residual electrical resistivity due to short-range order has been calculated for Cu100-xAlx (x=9.13,13.56, 14.5 and 14.76 in at pct) alloys using pseudopotential approach, and the results have been discussed in the light of experimental studies of the local-order structure of these alloys. In case of Cu85.5Al14.5, change in the total residual electrical resistivity due to neutron-irradiation effects has been estimated by including contributions from the short-range order and static atomic displacement correction. Our results show a decrease in the residual resistivity in the irradiated Cu-Al solid solution as compared to the unirradiated sample. This is in accordance with the experimental results展开更多
Cancer multidrug resistance(MDR)impairs the therapeutic efficacy of various chemotherapeutics.Novel approaches,particularly the development of MDR reversal agents,are critically needed to address this challenge.This s...Cancer multidrug resistance(MDR)impairs the therapeutic efficacy of various chemotherapeutics.Novel approaches,particularly the development of MDR reversal agents,are critically needed to address this challenge.This study demonstrates that tenacissoside I(TI),a compound isolated from Marsdenia tenacissima(Roxb.)Wight et Arn,traditionally used in clinical practice as an ethnic medicine for cancer treatment,exhibits significant MDR reversal effects in ABCB1-mediated MDR cancer cells.TI reversed the resistance of SW620/AD300 and KBV200 cells to doxorubicin(DOX)and paclitaxel(PAC)by downregulating ABCB1 expression and reducing ABCB1 drug transport function.Mechanistically,protein arginine methyltransferase 1(PRMT1),whose expression correlates with poor prognosis and shows positive association with both ABCB1 and EGFR expressions in tumor tissues,was differentially expressed in TI-treated SW620/AD300 cells.SW620/AD300 and KBV200 cells exhibited elevated levels of EGFR asymmetric dimethylarginine(aDMA)and enhanced PRMT1-EGFR interaction compared to their parental cells.Moreover,TI-induced PRMT1 downregulation impaired PRMT1-mediated aDMA of EGFR,PRMT1-EGFR interaction,and EGFR downstream signaling in SW620/AD300 and KBV200 cells.These effects were significantly reversed by PRMT1 overexpression.Additionally,TI demonstrated resistance reversal to PAC in xenograft models without detectable toxicities.This study establishes TI's MDR reversal effect in ABCB1-mediated MDR human cancer cells through inhibition of PRMT1-mediated aDMA of EGFR,suggesting TI's potential as an MDR modulator for improving chemotherapy outcomes.展开更多
To elucidate the yielding performance of compact yielding anchor cables in working state,a yielding mechanical model incorporating extrusion friction and fastening rotation under confining pressure is constructed.The ...To elucidate the yielding performance of compact yielding anchor cables in working state,a yielding mechanical model incorporating extrusion friction and fastening rotation under confining pressure is constructed.The yielding resistance enhancement effect(ω)caused by working environment constraints is evaluated through multi-layer composite sleeve hole expansion analysis,forming a theoretical framework for calculating the working yielding force.Laboratory and in-situ pull-out tests are conducted to determine the yielding performance and validate the analytical theory.The main conclusions are:(1)Yielding force and energy-release capacity increase withω,significantly outperforming the unconfined state.(2)In-situ tests under varying rockmass and geostress conditions(F1–F3)determine the yielding force increases to 183.4–290.1,204.0–290.8,and 235.0–327.1 kN.(3)The slight deviation(–12.5%to 6.2%)between the theoretical and measured yielding force confirms that the analytical theory effectively describes the working yielding performance.(4)ωincreases with higher geostress and improved rock mechanical properties,with initial geostress(σ_(0))and elastic modulus of surrounding rock(E_(3))identified as critical parameters.展开更多
This paper has discussed the effective resistivity ellipse and the paradoxical phenomenon of anisotropy. Two cases have been discussed, namely: there are three measuring lines at arbitrary angles with one another and...This paper has discussed the effective resistivity ellipse and the paradoxical phenomenon of anisotropy. Two cases have been discussed, namely: there are three measuring lines at arbitrary angles with one another and there are two mutually perpendicular measuring lines and an additional measurement of the transversal effective resistivity. For these cases, the paper has given the methods for quantitatively calculating the parameters of georesistivity anisotropy. The formulae given include those for calculating the azimuth (of the principal axis of minimum resistivity ρ 1, the average resistivity ( ρ 1ρ 3) 1/2 , (ρ 2ρ 3) 1/2 , and the anisotropy coefficient λ=(ρ 2/ρ 1 ) 1/2 . As a case history, the data observed by the Datong geoelectricity station have been processed with reference to the results of in situ resistivity measurement in media subjected to shear. The results of analysis have led to the following understandings. Before and after the Datong M S6.1 earthquake on October 19, 1989, the abnormal rise of NE trending georesistivity and abnormal fall of NW trending georesistivity observed at the Datong and Yangyuan stations were caused by the pure shear acting on the medium. The major principal compression was in NE direction, which made an acute angle with the strike of the seismic fault plane, and thus there was a greater shear stress but very small normal stress so that the fault was likely to slide but the earthquake was only of moderate magnitude. The states of stress in medium were the same before and after earthquake and therefore the georesistivity precursor was of the same sign as that of co seismic variations.展开更多
An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydr...An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.展开更多
The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1...The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1.4 wavelength/ NA （numerical aperture）,is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value （the depth of the ＂dip＂） and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD ＂dip＂. We conclude that the dip depth is very sensitive to the change in image contrast.展开更多
Overweight or obesity has become a serious public health problem in the world, scientists are concentrating their efforts on exploring novel ways to treat obesity. Nowadays, the availabilities of bariatric surgery and...Overweight or obesity has become a serious public health problem in the world, scientists are concentrating their efforts on exploring novel ways to treat obesity. Nowadays, the availabilities of bariatric surgery and pharmacotherapy have enhanced obesity treatment, but it should has support from diet, physical exercise and lifestyle modification, especially the functional food. Resistant starch, an indigestible starch, has been studied for years for its beneficial effects on regulating blood glucose level and lipid metabolism. The aim of this review is to summarize the effect of resistant starch on weight loss and the possible mechanisms. According to numerous previous studies it could be concluded that resistant starch can reduce fat accumulation, enhance insulin sensitivity, regulate blood glucose level and lipid metabolism. Recent investigations have focused on the possible associations between resistant starch and incretins as well as gut microbiota. Resistant starch seems to be a promising dietary fiber for the prevention or treatment of obesity and its related diseases.展开更多
Nitriding is employed for the hard Fe electrodeposition to produce a hard-facing and antiwear coating. It only takes 1 h for the hard Fe coating, which is much shorter than nitriding the Fe and steel. The results show...Nitriding is employed for the hard Fe electrodeposition to produce a hard-facing and antiwear coating. It only takes 1 h for the hard Fe coating, which is much shorter than nitriding the Fe and steel. The results showed that the nitriding can increase the microhardness, wear resistance of the coating, as well as the bonding strength of the coating with the substrate. Additionally it can eliminate the brittleness, turn the internal stress of the coating from tension to compression. The wear resistance of the nitrided Fe coating is 4.6 times as high as that of Cr coating. It is simple and economic to combine hard Fe electroplating and nitriding, which is a good technology of the tribological surface modification.展开更多
Cucumber seedlings were sprayed with different concentrations of LaCl_3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L^(-1) 2,4-dichlorophennoxy(2,4-D) for 24 h. The lea...Cucumber seedlings were sprayed with different concentrations of LaCl_3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L^(-1) 2,4-dichlorophennoxy(2,4-D) for 24 h. The leaves were harvested and rinsed with 5 mmol·L^(-1) EDTA. The concentrations of photosynthetic pigments, soluble protein and metabolites related to oxidative stress and the activities of antioxidant enzymes in leaves were assayed. The results show that the treatment with appropriate concentration of LaCl_3 has resistant effect on oxidative stress induced by 2, 4-D. Proper concentration of LaCl_3 promotes the activity of antioxidant system in plants and alleviates the damage caused by 2, 4-D.展开更多
Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille ...Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille equation is proposed. The resistance to gas migration is generally dynamic because of the variations in adsorption swelling and matrix shrinkage. Due to the limitations of experimental conditions,only a theoretical expression of resistance to gas migration in coal is deduced, and the impacts of tortuosity, effective stress and pore pressure on the resistance are then considered. To validate the proposed expression, previous data from other researchers are adopted for the history matching exercise, and the agreement between the two is good.展开更多
During heavy oil recovery in the Bohai Oilfield,substantial emulsification of oil and water occurred,primarily forming water-in-oil emulsions.This phenomenon could alter fluid dynamics within the subsurface porous med...During heavy oil recovery in the Bohai Oilfield,substantial emulsification of oil and water occurred,primarily forming water-in-oil emulsions.This phenomenon could alter fluid dynamics within the subsurface porous media,potentially impacting well production performance.To elucidate the properties of water-in-oil emulsions and their associated liquid resistance effects,this study conducted a series of rheological tests,microscopic examinations,and injection experiments.The results show that the droplet size and distribution of water-in-oil emulsions were primarily influenced by shear rate and water content,which in turn modified emulsion viscosity.The stability of water-in-oil emulsions was reduced when they flowed through porous media.The increase in emulsion viscosity and the liquid resistance effect collectively enhanced the seepage resistance of water-in-oil emulsions flowing through porous media.Notably,when the emulsion droplet size exceeded the pore throat size,over 90%of the total seepage resistance was attributable to the liquid resistance effect.Conversely,when the majority of the emulsion droplets were smaller than the pore throat,the viscosity accounted for more than 60%of the seepage resistance.Water-in-oil emulsions flowed through cores with permeabilities ranging from 50 to 100 mD,exhibiting threshold pressure gradients between 35 and 43 MPa/m.At a core permeability of 300 mD,the threshold pressure gradient was significantly reduced to 1 MPa/m.The presence of a waterin-oil emulsion in the reservoir could result in a production pressure differential falling below the threshold pressure,thereby reducing reservoir productivity.展开更多
The effect of sputtered Ti-50Al-10Cr and Ti-50A1-20Cr coatings on both isothermal and cyclic oxidation resistance at 800-900℃ and hot corrosion resistance at 850℃ of Ti-24Al-14Nb-3V was investigated. Results indicat...The effect of sputtered Ti-50Al-10Cr and Ti-50A1-20Cr coatings on both isothermal and cyclic oxidation resistance at 800-900℃ and hot corrosion resistance at 850℃ of Ti-24Al-14Nb-3V was investigated. Results indicated that Ti-24Al-14Nb-3V alloys exhibited poor oxidation resistance due to the formation of Al2O3+TiO2+AlNbO4 mixed scales in air at 800-900℃ and poor hot corrosion resistance due to the spoliation of scales formed in Na2SO4+K2SO4 melts at 850℃. Both Ti-50Al-10Cr and Ti-50Al-20Cr coatings remarkably improved the oxidation and hot corrosion resistance of Ti-24Al-14Nb-3V alloy.展开更多
The diffusive boundary layer （DBL） is the zone for matter exchange between surface water and aquatic sediments. To elucidate the influence of DBL on salt release from saline sediments to freshwater, two experiments ...The diffusive boundary layer （DBL） is the zone for matter exchange between surface water and aquatic sediments. To elucidate the influence of DBL on salt release from saline sediments to freshwater, two experiments with or without wind blowing were conducted. According to the experiments, a 3.5 cm DBL is formed above the smoothed sediments at a steady wind field and this thickness is greater than other studies. The observed flux of salt through the DBL is 6% larger than the calculated value from Fick＇ s first law. The results indicate that molecular diffusion is the dominant mechanism for salt transport through the DBL. The presence of DBL suppresses the hydrodynamic enhancement for matter exchange between sediments and overlying water. Therefore, salts in the sediments of a polder reservoir may influence the water quality chronically.展开更多
The current-induced resistive switching behavior in the micron-scale pillars of low-doped La0.9Sr0.1MnO3 thin films using laser molecular-beam epitaxy was reported. It was demonstrated that the current-voltage curves ...The current-induced resistive switching behavior in the micron-scale pillars of low-doped La0.9Sr0.1MnO3 thin films using laser molecular-beam epitaxy was reported. It was demonstrated that the current-voltage curves at 120 K showed hysteresis with several threshold currents corresponding to the switching in resistance to metastable low resistance states, and finally, four closed loops were formed. A mode was proposed, which was based on the low-temperature canted antiferromagnetism ordering for a lightly doped insulating regime.展开更多
Antibiotic wastewater contains a variety of pollutant stressors that can induce and promote antibiotic resistance(AR)when released into the environment.Although these substances are mostly in concentrations lower than...Antibiotic wastewater contains a variety of pollutant stressors that can induce and promote antibiotic resistance(AR)when released into the environment.Although these substances are mostly in concentrations lower than those known to induce AR individually,it is possible that antibiotic wastewater discharge might still promote the AR transmission risk via additive or synergistic effects.However,the comprehensive effect of antibiotic wastewater on AR development has rarely been evaluated,and its treatment efficiency remains unknown.Here,samples were collected from different stages of a cephalosporin production wastewater treatment plant,and the potential AR induction effect of their chemical mixtures was explored through the exposure of the antibiotic-sensitive Escherichia coli K12 strain.Incubation with raw cephalosporin production wastewater significantly promoted mutation rates(3.6×10^(3)-9.3×10^(3)-fold)and minimum inhibition concentrations(6.0-6.7-fold)of E.coli against ampicillin and chloramphenicol.This may be attributed to the inhibition effect and oxidative stress of cephalosporin wastewater on E.coli.The AR induction effect of cephalosporin wastewater decreased after the coagulation sedimentation treatment and was completely removed after the full treatment process.A Pearson correlation analysis revealed that the reduction in the AR induction effect had a strong positive correlation with the removal of organics and biological toxicity.This indicates that the antibiotic wastewater treatment had a collaborative processing effect of conventional pollutants,toxicity,and the AR induction effect.This study illustrates the potential AR transmission risk of antibiotic wastewater and highlights the need for its adequate treatment.展开更多
Pathology of an internal organ causes significant rectification of electrical currents （diode phenomenon） in related skin areas - organ projection areas （OPAs）, once the resistance ‘breakthrough effect＇ has been...Pathology of an internal organ causes significant rectification of electrical currents （diode phenomenon） in related skin areas - organ projection areas （OPAs）, once the resistance ‘breakthrough effect＇ has been induced in the skin. Also, the impedance of the diseased organ＇s projection areas is increased. The aim of this double-blind study was to confirm these phenomena statistically using a broad spectrum of measuring parameters. Skin impedance vs. measurement frequency, skin impedance vs. applied voltage, and skin resistance vs. voltage were evaluated at 335 auricular OPAs related to the healthy internal organs and 203 auricular OPAs related to the diseased organs. These measurements confirmed that the skin electrical characteristics of specific locations are dependent on the health state of the corresponding internal organs. It was found that the impedance of OPAs corresponding to the healthy internal organs equals 185 ＋ 291 k,Q at 10Hz and decreases to 64 ± 49 kΩ at 10kHz; and that the impedance of OPAs related to the diseased organs equals 7.5 ± 2.2 MΩ at 10Hz and 99 ± 50kΩ at 10kHz. The disparity of the impedances between the healthy and diseased organs related OPAs is greater at higher potentials. The skin resistance, when measured with a negatively polarized point electrode, undergoes a rapid resistance decrease of approximately two orders of magnitude, if the applied current is sufficient. After this reversible ‘breakthrough effect＇ is obtained the skin exhibits rectification. The degree of rectification is low for OPAs related to the healthy organs. For OPAs related to the diseased organs, the resistance measured with a positive polarisation of measuring electrode could be five times greater than the resistance measured at the same voltage with the same but negatively polarised electrode. The disparity between the resistance measured with a negatively and with a positively polarised electrode at OPAs related to the diseased organs was greater at higher measurement voltages. The influence of organ pathology on the electrical parameters of related OPAs does not depend on the kind of internal organ and is not affected by the etiology of pathology. The degree of rectification or difference in impedance is proportional to the extent of the pathological process within the related organ.展开更多
Background： Pathology of an internal organ causes significant rectification of electrical currents （diode phenomenon） in related skin areas once the resistance ＇breakthrough effect＇ has been induced in the skin. ...Background： Pathology of an internal organ causes significant rectification of electrical currents （diode phenomenon） in related skin areas once the resistance ＇breakthrough effect＇ has been induced in the skin. Objective： Localization of auricular projection area of the liver and evaluation of its usefulness in the monitoring of viral hepatitis. Design, Patients and Setting： Comparative study of the degree of electrical rectification measured at various spots in the auricular concha region, in 19 inpatients with hepatitis B and 15 clinically healthy volunteers, at the Department of Infectious Diseases, Provincial Teaching Hospital, Tychy, Poland. Intervention： Evaluation of electrical rectification at various spots on the auricular concha using a ＂rectification ratio＂ that quantifies the degree of rectification （normal range： 0-60%）. Main outcome measure： The location of the skin area where a statistically significant difference existed between the rectification ratios was observed in patients （82±12% at the time of the ＇peak period＇） versus controls （42±8%）. Results： A location was identified on the ear auricle where the electrical rectification phenomenon demonstrated a dependence on the presence of hepatitis. Conclusions： Liver projection area exists on the ear auricle which is located within the region of cymba conchae, next to anthelix and the cavity of concha. The existence of viral hepatitis causes this skin area to show a higher degree of electrical rectification once the skin resistance ＇breakthrough effect＇ has been induced. Evaluation of the rectification phenomenon of the liver proiection area provides a method of non-invasive monitoring of viral hepatitis.展开更多
基金National Natural Science Foundation of China(11875039)Shanxi Scholarship Council of China(2023-033)+2 种基金Fundamental Research Program of Shanxi Province(202303021221071)China Baowu Low Carbon Metallurgical Innovation Foundation(2022)2023 Anhui Major Industrial Innovation Plan Project。
文摘The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.
基金The project supported by the National Natural Science Foundation of China (10172070)
文摘The dynamic effective shear strength of saturated sand under cyclic loading is discussed in this paper.The discussion includes the transient time depen- dency behaviors based on the analysis of the results obtained in conventional cyclic triaxial tests and cyclic torsional shear triaxial tests.It has been found that the dy- namic effective shear strength is composed of effective frictional resistance and viscous resistance,which are characterized by the strain rate dependent feature of strength magnitude,the coupling of consolidation stress with cyclic stress and the dependency of time needed to make the soil strength sufficiently mobilized,and can also be ex- pressed by the extended Mohr-Coulomb's law.The two strength parameters of the dynamic effective internal frictional angle φd and the dynamic viscosity coefficient η are determined.The former is unvaried for different number of cyclic loading,dy- namic stress form and consolidation stress ratio.And the later is unvaried for the different dynamic shear strain rate γt developed during the sand liquefaction,but increases with the increase of initial density of sand.The generalization of dynamic effective stress strength criterion in the 3-dimensional effective stress space is studied in detail for the purpose of its practical use.
基金Supported by the Fund of Science and Technology on Vacuum Technology and Physics Laboratory of Lanzhou Institute of Physics under Grant No YSC0715the National Natural Science Foundation of China under Grant No 62601210the Civil Aerospace Technology Research Project under Grant No D010509
文摘The effects of three different typical resistivity models（Spitzer, Z＆L and M＆G） on the performance of pulsed inductive acceleration plasma are studied. Numerical results show that their influences decrease with the increase of the plasma temperature. The significant discriminations among them appear at the plasma temperature lower than 2.5 eV, and the maximum gap of the pulsed inductive plasma accelerated efficiency is approximately 2.5%.Moreover, the pulsed inductive plasma accelerated efficiency is absolutely related to the dynamic impedance parameters, such as voltage, inductance, capacitance and flow rate. However, the distribution of the efficiency as a function of plasma temperature with three resistivity models has nothing to do with the dynamic impedance parameter.
文摘Residual electrical resistivity due to short-range order has been calculated for Cu100-xAlx (x=9.13,13.56, 14.5 and 14.76 in at pct) alloys using pseudopotential approach, and the results have been discussed in the light of experimental studies of the local-order structure of these alloys. In case of Cu85.5Al14.5, change in the total residual electrical resistivity due to neutron-irradiation effects has been estimated by including contributions from the short-range order and static atomic displacement correction. Our results show a decrease in the residual resistivity in the irradiated Cu-Al solid solution as compared to the unirradiated sample. This is in accordance with the experimental results
基金supported by the National Natural Science Foundation of China(Nos.82274211 and 82474190)the Natural Science Foundation of Tianjin(Nos.24JCZDJC00120 and 24PTLYHZ00280)Liaoning Provincial Department of Education Basic Research Projects for Higher Education Institutions(No.LJ212510163021)。
文摘Cancer multidrug resistance(MDR)impairs the therapeutic efficacy of various chemotherapeutics.Novel approaches,particularly the development of MDR reversal agents,are critically needed to address this challenge.This study demonstrates that tenacissoside I(TI),a compound isolated from Marsdenia tenacissima(Roxb.)Wight et Arn,traditionally used in clinical practice as an ethnic medicine for cancer treatment,exhibits significant MDR reversal effects in ABCB1-mediated MDR cancer cells.TI reversed the resistance of SW620/AD300 and KBV200 cells to doxorubicin(DOX)and paclitaxel(PAC)by downregulating ABCB1 expression and reducing ABCB1 drug transport function.Mechanistically,protein arginine methyltransferase 1(PRMT1),whose expression correlates with poor prognosis and shows positive association with both ABCB1 and EGFR expressions in tumor tissues,was differentially expressed in TI-treated SW620/AD300 cells.SW620/AD300 and KBV200 cells exhibited elevated levels of EGFR asymmetric dimethylarginine(aDMA)and enhanced PRMT1-EGFR interaction compared to their parental cells.Moreover,TI-induced PRMT1 downregulation impaired PRMT1-mediated aDMA of EGFR,PRMT1-EGFR interaction,and EGFR downstream signaling in SW620/AD300 and KBV200 cells.These effects were significantly reversed by PRMT1 overexpression.Additionally,TI demonstrated resistance reversal to PAC in xenograft models without detectable toxicities.This study establishes TI's MDR reversal effect in ABCB1-mediated MDR human cancer cells through inhibition of PRMT1-mediated aDMA of EGFR,suggesting TI's potential as an MDR modulator for improving chemotherapy outcomes.
基金supported by the National Natural Science Foundation of China(Nos.U2468217,U2034205,and 52308391)。
文摘To elucidate the yielding performance of compact yielding anchor cables in working state,a yielding mechanical model incorporating extrusion friction and fastening rotation under confining pressure is constructed.The yielding resistance enhancement effect(ω)caused by working environment constraints is evaluated through multi-layer composite sleeve hole expansion analysis,forming a theoretical framework for calculating the working yielding force.Laboratory and in-situ pull-out tests are conducted to determine the yielding performance and validate the analytical theory.The main conclusions are:(1)Yielding force and energy-release capacity increase withω,significantly outperforming the unconfined state.(2)In-situ tests under varying rockmass and geostress conditions(F1–F3)determine the yielding force increases to 183.4–290.1,204.0–290.8,and 235.0–327.1 kN.(3)The slight deviation(–12.5%to 6.2%)between the theoretical and measured yielding force confirms that the analytical theory effectively describes the working yielding performance.(4)ωincreases with higher geostress and improved rock mechanical properties,with initial geostress(σ_(0))and elastic modulus of surrounding rock(E_(3))identified as critical parameters.
文摘This paper has discussed the effective resistivity ellipse and the paradoxical phenomenon of anisotropy. Two cases have been discussed, namely: there are three measuring lines at arbitrary angles with one another and there are two mutually perpendicular measuring lines and an additional measurement of the transversal effective resistivity. For these cases, the paper has given the methods for quantitatively calculating the parameters of georesistivity anisotropy. The formulae given include those for calculating the azimuth (of the principal axis of minimum resistivity ρ 1, the average resistivity ( ρ 1ρ 3) 1/2 , (ρ 2ρ 3) 1/2 , and the anisotropy coefficient λ=(ρ 2/ρ 1 ) 1/2 . As a case history, the data observed by the Datong geoelectricity station have been processed with reference to the results of in situ resistivity measurement in media subjected to shear. The results of analysis have led to the following understandings. Before and after the Datong M S6.1 earthquake on October 19, 1989, the abnormal rise of NE trending georesistivity and abnormal fall of NW trending georesistivity observed at the Datong and Yangyuan stations were caused by the pure shear acting on the medium. The major principal compression was in NE direction, which made an acute angle with the strike of the seismic fault plane, and thus there was a greater shear stress but very small normal stress so that the fault was likely to slide but the earthquake was only of moderate magnitude. The states of stress in medium were the same before and after earthquake and therefore the georesistivity precursor was of the same sign as that of co seismic variations.
基金financially supported by the Joint Fund of Coal, set up by National Natural Science Foundation of China and Shenhua Co., Ltd.(U1261104)the National Natural Science Foundation of China (21276041)+3 种基金the Program for New Century Excellent Talents in University (NCET-12-0079)the Natural Science Foundation of Liaoning Province (2015020200)the Fundamental Research Funds for the Central Universities (DUT15LK41)the Science and Technology Development Program of Hangzhou (20130533B14)~~
文摘An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.
文摘The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1.4 wavelength/ NA （numerical aperture）,is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value （the depth of the ＂dip＂） and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD ＂dip＂. We conclude that the dip depth is very sensitive to the change in image contrast.
基金supported by the National Natural Science Foundation major international(regional)joint research project(81220108006)to WJYoung Scientists Fund of National Natural Science Foundation(81200292),Young Scientists Fund of National Natural Science Foundation(81200655)to LSShanghai Rising-Star Program(13QA1402900)and Hong Kong Scholars Program(XJ2013035)to HL
文摘Overweight or obesity has become a serious public health problem in the world, scientists are concentrating their efforts on exploring novel ways to treat obesity. Nowadays, the availabilities of bariatric surgery and pharmacotherapy have enhanced obesity treatment, but it should has support from diet, physical exercise and lifestyle modification, especially the functional food. Resistant starch, an indigestible starch, has been studied for years for its beneficial effects on regulating blood glucose level and lipid metabolism. The aim of this review is to summarize the effect of resistant starch on weight loss and the possible mechanisms. According to numerous previous studies it could be concluded that resistant starch can reduce fat accumulation, enhance insulin sensitivity, regulate blood glucose level and lipid metabolism. Recent investigations have focused on the possible associations between resistant starch and incretins as well as gut microbiota. Resistant starch seems to be a promising dietary fiber for the prevention or treatment of obesity and its related diseases.
文摘Nitriding is employed for the hard Fe electrodeposition to produce a hard-facing and antiwear coating. It only takes 1 h for the hard Fe coating, which is much shorter than nitriding the Fe and steel. The results showed that the nitriding can increase the microhardness, wear resistance of the coating, as well as the bonding strength of the coating with the substrate. Additionally it can eliminate the brittleness, turn the internal stress of the coating from tension to compression. The wear resistance of the nitrided Fe coating is 4.6 times as high as that of Cr coating. It is simple and economic to combine hard Fe electroplating and nitriding, which is a good technology of the tribological surface modification.
文摘Cucumber seedlings were sprayed with different concentrations of LaCl_3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L^(-1) 2,4-dichlorophennoxy(2,4-D) for 24 h. The leaves were harvested and rinsed with 5 mmol·L^(-1) EDTA. The concentrations of photosynthetic pigments, soluble protein and metabolites related to oxidative stress and the activities of antioxidant enzymes in leaves were assayed. The results show that the treatment with appropriate concentration of LaCl_3 has resistant effect on oxidative stress induced by 2, 4-D. Proper concentration of LaCl_3 promotes the activity of antioxidant system in plants and alleviates the damage caused by 2, 4-D.
基金supported by the State Key Research Development Program of China (Nos. 2016YFC0801402 and 2016YFC0600708)the National Natural Science Foundation of China (No. 51474219)
文摘Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille equation is proposed. The resistance to gas migration is generally dynamic because of the variations in adsorption swelling and matrix shrinkage. Due to the limitations of experimental conditions,only a theoretical expression of resistance to gas migration in coal is deduced, and the impacts of tortuosity, effective stress and pore pressure on the resistance are then considered. To validate the proposed expression, previous data from other researchers are adopted for the history matching exercise, and the agreement between the two is good.
基金financially supported by the National Natural Science Foundation of China(No.ZX20230212)。
文摘During heavy oil recovery in the Bohai Oilfield,substantial emulsification of oil and water occurred,primarily forming water-in-oil emulsions.This phenomenon could alter fluid dynamics within the subsurface porous media,potentially impacting well production performance.To elucidate the properties of water-in-oil emulsions and their associated liquid resistance effects,this study conducted a series of rheological tests,microscopic examinations,and injection experiments.The results show that the droplet size and distribution of water-in-oil emulsions were primarily influenced by shear rate and water content,which in turn modified emulsion viscosity.The stability of water-in-oil emulsions was reduced when they flowed through porous media.The increase in emulsion viscosity and the liquid resistance effect collectively enhanced the seepage resistance of water-in-oil emulsions flowing through porous media.Notably,when the emulsion droplet size exceeded the pore throat size,over 90%of the total seepage resistance was attributable to the liquid resistance effect.Conversely,when the majority of the emulsion droplets were smaller than the pore throat,the viscosity accounted for more than 60%of the seepage resistance.Water-in-oil emulsions flowed through cores with permeabilities ranging from 50 to 100 mD,exhibiting threshold pressure gradients between 35 and 43 MPa/m.At a core permeability of 300 mD,the threshold pressure gradient was significantly reduced to 1 MPa/m.The presence of a waterin-oil emulsion in the reservoir could result in a production pressure differential falling below the threshold pressure,thereby reducing reservoir productivity.
文摘The effect of sputtered Ti-50Al-10Cr and Ti-50A1-20Cr coatings on both isothermal and cyclic oxidation resistance at 800-900℃ and hot corrosion resistance at 850℃ of Ti-24Al-14Nb-3V was investigated. Results indicated that Ti-24Al-14Nb-3V alloys exhibited poor oxidation resistance due to the formation of Al2O3+TiO2+AlNbO4 mixed scales in air at 800-900℃ and poor hot corrosion resistance due to the spoliation of scales formed in Na2SO4+K2SO4 melts at 850℃. Both Ti-50Al-10Cr and Ti-50Al-20Cr coatings remarkably improved the oxidation and hot corrosion resistance of Ti-24Al-14Nb-3V alloy.
基金The National Science Foundation of China under contract No.40572142the Doctoral Foundation of the Ministry of Education of China under contract No.20040423016.
文摘The diffusive boundary layer （DBL） is the zone for matter exchange between surface water and aquatic sediments. To elucidate the influence of DBL on salt release from saline sediments to freshwater, two experiments with or without wind blowing were conducted. According to the experiments, a 3.5 cm DBL is formed above the smoothed sediments at a steady wind field and this thickness is greater than other studies. The observed flux of salt through the DBL is 6% larger than the calculated value from Fick＇ s first law. The results indicate that molecular diffusion is the dominant mechanism for salt transport through the DBL. The presence of DBL suppresses the hydrodynamic enhancement for matter exchange between sediments and overlying water. Therefore, salts in the sediments of a polder reservoir may influence the water quality chronically.
基金the National Basic Research Program of Chinathe National Natural Science Foundation of China+1 种基金the Key Project of Chinese Ministry of EducationBeijing Natural Science Foundation
文摘The current-induced resistive switching behavior in the micron-scale pillars of low-doped La0.9Sr0.1MnO3 thin films using laser molecular-beam epitaxy was reported. It was demonstrated that the current-voltage curves at 120 K showed hysteresis with several threshold currents corresponding to the switching in resistance to metastable low resistance states, and finally, four closed loops were formed. A mode was proposed, which was based on the low-temperature canted antiferromagnetism ordering for a lightly doped insulating regime.
基金supported by the National Key Research and Development Program of China(No.2017ZX07103-007)。
文摘Antibiotic wastewater contains a variety of pollutant stressors that can induce and promote antibiotic resistance(AR)when released into the environment.Although these substances are mostly in concentrations lower than those known to induce AR individually,it is possible that antibiotic wastewater discharge might still promote the AR transmission risk via additive or synergistic effects.However,the comprehensive effect of antibiotic wastewater on AR development has rarely been evaluated,and its treatment efficiency remains unknown.Here,samples were collected from different stages of a cephalosporin production wastewater treatment plant,and the potential AR induction effect of their chemical mixtures was explored through the exposure of the antibiotic-sensitive Escherichia coli K12 strain.Incubation with raw cephalosporin production wastewater significantly promoted mutation rates(3.6×10^(3)-9.3×10^(3)-fold)and minimum inhibition concentrations(6.0-6.7-fold)of E.coli against ampicillin and chloramphenicol.This may be attributed to the inhibition effect and oxidative stress of cephalosporin wastewater on E.coli.The AR induction effect of cephalosporin wastewater decreased after the coagulation sedimentation treatment and was completely removed after the full treatment process.A Pearson correlation analysis revealed that the reduction in the AR induction effect had a strong positive correlation with the removal of organics and biological toxicity.This indicates that the antibiotic wastewater treatment had a collaborative processing effect of conventional pollutants,toxicity,and the AR induction effect.This study illustrates the potential AR transmission risk of antibiotic wastewater and highlights the need for its adequate treatment.
文摘Pathology of an internal organ causes significant rectification of electrical currents （diode phenomenon） in related skin areas - organ projection areas （OPAs）, once the resistance ‘breakthrough effect＇ has been induced in the skin. Also, the impedance of the diseased organ＇s projection areas is increased. The aim of this double-blind study was to confirm these phenomena statistically using a broad spectrum of measuring parameters. Skin impedance vs. measurement frequency, skin impedance vs. applied voltage, and skin resistance vs. voltage were evaluated at 335 auricular OPAs related to the healthy internal organs and 203 auricular OPAs related to the diseased organs. These measurements confirmed that the skin electrical characteristics of specific locations are dependent on the health state of the corresponding internal organs. It was found that the impedance of OPAs corresponding to the healthy internal organs equals 185 ＋ 291 k,Q at 10Hz and decreases to 64 ± 49 kΩ at 10kHz; and that the impedance of OPAs related to the diseased organs equals 7.5 ± 2.2 MΩ at 10Hz and 99 ± 50kΩ at 10kHz. The disparity of the impedances between the healthy and diseased organs related OPAs is greater at higher potentials. The skin resistance, when measured with a negatively polarized point electrode, undergoes a rapid resistance decrease of approximately two orders of magnitude, if the applied current is sufficient. After this reversible ‘breakthrough effect＇ is obtained the skin exhibits rectification. The degree of rectification is low for OPAs related to the healthy organs. For OPAs related to the diseased organs, the resistance measured with a positive polarisation of measuring electrode could be five times greater than the resistance measured at the same voltage with the same but negatively polarised electrode. The disparity between the resistance measured with a negatively and with a positively polarised electrode at OPAs related to the diseased organs was greater at higher measurement voltages. The influence of organ pathology on the electrical parameters of related OPAs does not depend on the kind of internal organ and is not affected by the etiology of pathology. The degree of rectification or difference in impedance is proportional to the extent of the pathological process within the related organ.
文摘Background： Pathology of an internal organ causes significant rectification of electrical currents （diode phenomenon） in related skin areas once the resistance ＇breakthrough effect＇ has been induced in the skin. Objective： Localization of auricular projection area of the liver and evaluation of its usefulness in the monitoring of viral hepatitis. Design, Patients and Setting： Comparative study of the degree of electrical rectification measured at various spots in the auricular concha region, in 19 inpatients with hepatitis B and 15 clinically healthy volunteers, at the Department of Infectious Diseases, Provincial Teaching Hospital, Tychy, Poland. Intervention： Evaluation of electrical rectification at various spots on the auricular concha using a ＂rectification ratio＂ that quantifies the degree of rectification （normal range： 0-60%）. Main outcome measure： The location of the skin area where a statistically significant difference existed between the rectification ratios was observed in patients （82±12% at the time of the ＇peak period＇） versus controls （42±8%）. Results： A location was identified on the ear auricle where the electrical rectification phenomenon demonstrated a dependence on the presence of hepatitis. Conclusions： Liver projection area exists on the ear auricle which is located within the region of cymba conchae, next to anthelix and the cavity of concha. The existence of viral hepatitis causes this skin area to show a higher degree of electrical rectification once the skin resistance ＇breakthrough effect＇ has been induced. Evaluation of the rectification phenomenon of the liver proiection area provides a method of non-invasive monitoring of viral hepatitis.
