In this work,a new structure is used to enhance the nonlinear effect in the cavity,which improvesthe performance of the 1.3μm broadband swept source.The swept source adopts a semiconductoroptical amplifier(SOA),a cir...In this work,a new structure is used to enhance the nonlinear effect in the cavity,which improvesthe performance of the 1.3μm broadband swept source.The swept source adopts a semiconductoroptical amplifier(SOA),a circulator,a coupler,and a tunable filter.In the structure,the lightpasses through the nonlinear medium(SOA)twice in two opposite directions,which excites thenonlinear ffect and increases the performance of the swept source.The tunable filter is based on apolygon rotating mirror and gratings.Traditionally,multiple SOAs are adopted to improve thesweep range and the optical power,which increases the cost and complexity of the swept source.The method proposed in this paper can improve the spectral range and optical power of the sweptsources without additional accessories.For the short-cavity swept source,the power increasesfrom 6 mW to 7.7 mW,and the sweep range increases from 98 nm to 120 nm.The broadband swept sources could have wide applications in biomedical imaging,sensor system,measurementand so on.展开更多
The influence of different concentration of oxalic acid matrix on elemental inductively coupled plasma mass spectrometry (ICP-MS) has been investigated. It has been proved that the sensitivity of analytes can be sig...The influence of different concentration of oxalic acid matrix on elemental inductively coupled plasma mass spectrometry (ICP-MS) has been investigated. It has been proved that the sensitivity of analytes can be significantly enhanced by adding small amounts of oxalic acid medium with adjusted nebulizer flow-rate gas, especially for the elements with ionization potential between 9 and 11 eV. Oxalic acid, as an enhancement agent, can be used to compensate the signal depression caused by inorganic matrix and to improve the detection limits about two to eight times, for the hard-to-ionize elements in ICP-MS determination.展开更多
Surface plasmon resonance of noble metal nanoparticles leads to the optical absorption enhancement effects,which have great potential applications in solar cell.By using the general numerical method of discrete dipole...Surface plasmon resonance of noble metal nanoparticles leads to the optical absorption enhancement effects,which have great potential applications in solar cell.By using the general numerical method of discrete dipole approximation (DDA),we study the absorption and scattering properties of two-dimensional square silver nanodisks (2D SSN) arrays on the single crystal silicon solar cell.Based on the effective reflective index model of the single crystal silicon solar cell,we investigate the optical enhancement absorption of light energy by varying the light incident direction,particle size,aspect ratio,and interparticle spacing of the silver nanodisks.The peak values and position of the optical extinction spectra of the 2D square arrays of noble metal nanodisks are obtained with the different array structures.展开更多
Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × ...Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × 4 and a unit frame area of 60 m<sup>2</sup>. A total of 58,201 eggs were collected by 24 monitoring times, of which 30,441 were from Lukou and 27,760 from Hengyang. 3831 fish eggs identify 8 fish species using morphological or molecular biological methods. The results showed that the number of eggs peaked from the 8<sup>th</sup> day to the 24<sup>th</sup> day after the nest entered the water, and then decreased rapidly. There was significant negative correlation between egg number in per m<sup>2</sup> fish nest and days of fish nest (P < 0.01). The economic benefits of artificial fish nests were RMB 11.81 million. The artificial fish nest can not only increase the population of fish, but also has significant economic benefits.展开更多
Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
Objective: To observe and assess the efficacy enhancing and toxicity attenuating effect of Nuzhen Yangyin Granule (NYG) to the anti-parkinsonism (paralysis agitans) therapy with medopa and ar-tane. Methods: Adopting t...Objective: To observe and assess the efficacy enhancing and toxicity attenuating effect of Nuzhen Yangyin Granule (NYG) to the anti-parkinsonism (paralysis agitans) therapy with medopa and ar-tane. Methods: Adopting the randomized double-blinded method, the effect of adding NYG to 30 patients with Parkinsonism in the treated group,展开更多
Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits ina...Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide.Herein,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory.The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis performance.The optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.展开更多
Enhanced damage to the full-filled fuel tank,impacted by the cold pressed and sintered PTFE/Al/W reactive material projectile(RMP)with a density of 7.8 g/cm3,is investigated experimentally and theoretically.The fuel t...Enhanced damage to the full-filled fuel tank,impacted by the cold pressed and sintered PTFE/Al/W reactive material projectile(RMP)with a density of 7.8 g/cm3,is investigated experimentally and theoretically.The fuel tank is a rectangular structure,welded by six pieces of 2024 aluminum plate with a thickness of 6 mm,and filled with RP-3 aviation kerosene.Experimental results show that the kerosene is ignited by the RMP impact at a velocity above 1062 m/s,and a novel interior ignition phenomenon which is closely related to the rupture effect of the fuel tank is observed.However,the traditional steel projectile with the same mass and dimension requires a velocity up to 1649 m/s to ignite the kerosene.Based on the experimental results,the radial pressure field is considered to be the main reason for the shear failure of weld.For mechanism considerations,the chemical energy released by the RMP enhances the hydrodynamic ram(HRAM)effect and provides additional ignition sources inside the fuel tank,thereby enhancing both rupture and ignition effects.Moreover,to further understand the enhanced ignition effect of RMP,the reactive debris temperature inside the kerosene is analyzed theoretically.The initiated reactive debris with high temperature provides effective interior ignition sources to ignite the kerosene,resulting in the enhanced ignition of the kerosene.展开更多
Integral thin shells made of high strength aluminum alloys are urgently needed in new generation transportation equipment. There are challenges to overcoming the co-existing problems of wrinkling and splitting by the ...Integral thin shells made of high strength aluminum alloys are urgently needed in new generation transportation equipment. There are challenges to overcoming the co-existing problems of wrinkling and splitting by the cold forming and hot forming processes. An innovative technology of ultra-low temperature forming has been invented for aluminum alloy thin shells by the new phenomenon of ‘dual enhancement effect’. That means plasticity and hardening are enhanced simultaneously at ultra-low temperatures. In this perspective, the dual enhancement effect is described, and the development, current state and prospects of this new forming method are introduced. This innovative method can provide a new approach for integral aluminum alloy components with large size, ultra-thin thickness, and high strength. An integral tank dome of rocket with 2 m in diameter was formed by using a blank sheet with the same thickness as the final component, breaking through the limit value of thickness-diameter ratio.展开更多
In terms of the reaction of COreduction to CO with hydrogen, COconversion is very low at low temperature due to the limitation of thermodynamic equilibrium(TE). To overcome this limitation, plasma catalytic reductio...In terms of the reaction of COreduction to CO with hydrogen, COconversion is very low at low temperature due to the limitation of thermodynamic equilibrium(TE). To overcome this limitation, plasma catalytic reduction of COto CO in a catalyst-filled dielectric barrier discharge(DBD) reactor is studied. An enhanced effect of plasma on the reaction over Au/CeOcatalysts is observed. For both the conventionally catalytic(CC) and plasma catalytic(PC, Pin= 15 W) reactions under conditions of 400 °C, H/CO= 1,200 SCCM, GHSV = 12,000 mL·gcat·h, COconversions over Au/CeOreach 15.4% and 25.5% due to the presence of Au, respectively, however, those over CeOare extremely low and negligible. Moreover,COconversion over Au/CeOin the PC reaction exceeds 22.4% of the TE conversion. Surface intermediate species formed on the catalyst samples during the reactions are determined by in-situ temperatureprogrammed decomposition(TPD) technique. Interestingly, it disclosed that in the PC reaction, the formation of formate intermediate is enhanced by plasma, and the acceleration by plasma in the decomposition of formate species is much greater than that in the formation of formate species on Au/CeO. Enhancement factor is introduced to quantify the enhanced effect of plasma. Lower reactor temperature, higher gas hourly space velocity(GHSV), and lower molar ratio of H/COwould be associated with larger enhancement factor.展开更多
The novel fusion proteins harbering human or mouse interferon combined with epidermalgrowth factor receptor binding domain were constructed using methods of genetic and proteinengineering. The fusion proteins were ass...The novel fusion proteins harbering human or mouse interferon combined with epidermalgrowth factor receptor binding domain were constructed using methods of genetic and proteinengineering. The fusion proteins were assayed to retain complete antiviral activities. The EGFreceptor binding moiety of the fusion proteins exhibited competitive binding saainst 125 I-EGFfor EGF receptbrs on A431 cells. The fusion proteins were shown to be more potent in in-hibiting the growth of cultured target carcinoma cells than interferon-y alone. Experimentaldata derived from rnouse Bl6 malignant melanoma models indicates that the weight of tumorin mice treated with IFN fusion proteins was significantly smaller than that of mice treatedwith interferon-y alone. The work here is unprecedented in the world and provides a reliableevidence to supPOrt the upcoming clinical employment of a class of interferons that specificallytarget tumor cell展开更多
Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles)...Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles) was observed in H22 liver cancer bearing mice.The RhB-micelles were prepared by conjugating rhodamine B with the DHP units of amphiphilic block copolymer PEG-b-P(LA-co-DHP) followed by subsequent self-assembling of the conjugate.The parent copolymer PEG-b-P(LA-co-DHP) was synthesized by ring-opening copolymerization of LA and DHP with PEG as macroinitiator and diethyl zinc(ZnEt2) as catalyst.The micelles have a spherical shape and the average diameter is ca.50 nm by TEM(transmission electron microscope) or 80 nm by DLS(dynamic light scattering).Their in vitro cell uptake experiment by CLSM(confocal laser scanning microscopy) and flow cytometry showed preferential internalization of micelles by MCF-7 human breast cancer cells to free RhB.The in vivo tests by live animal imaging and ex vivo excised organ imaging showed that after vena tail injection,free RhB molecules were distributed in the whole body through the circulation system and then gradually metabolized and excreted and there was no preferential partition in tumor bed from the beginning to the end.But the RhB-micelles were preferentially distributed to the tumor bed so that their concentration(fluorescent intensity) in tumor bed got the level of the liver at a certain time point between 1 and 6 h and reached a maximum relative intensity at around 12 h,indicating an obvious EPR effect of RhB-micelles in H22 liver cancer.展开更多
When a penetrator with enhanced lateral effect(PELE) impacts on a reinforced concrete(RC) target,the target is damaged with a large opening.An understanding of how PELE projectile parameters affect the opening dimensi...When a penetrator with enhanced lateral effect(PELE) impacts on a reinforced concrete(RC) target,the target is damaged with a large opening.An understanding of how PELE projectile parameters affect the opening dimension,is essential for effective design of the PELE projectile.In this study,under the condition that the impact velocity and target parameters(strength and thickness) were fixed values,the important influence factors of the PELE(jacket wall thickness B,jacket material strength Y1,filling material strength Y2 and angle of monolithic jacket θ) were determined by a dimensional analysis.Tests and simulations of the PELE penetrating the RC target were conducted to analyze the influence of these factors on opening diameter(D,an equivalent diameter under relative kinetic energy).Based on the test and simulation results,it is found that the influence of these factors B,Y1 and θ on the deformation mode of the jacket shows a similar trend:as values of the three factors decrease,the jacket deforms from small bending deformation to large one,and then to curling deformation.This causes the opening diameter to first increase with the decrease of these three factors,and then decreases.It is well known that the bending resistance of the jacket is related to these factors B,Y1 and θ.Therefore,a plastic limit bending moment(M0) of the jacket was quoted to characterize the influence of these factors on the bending deformation of the jacket and the opening diameter of the target.The influence factor Y2 causes D to first increase with the increase of Y2,and then decreases.A formula was developed to predict the opening diameter,whose influence parameters were considered in a dimensionless way.It has been shown that the dimensionless opening diameter D/d1 is dependent on two dimensionless parameters■ and■,where d1 and fc are the outer diameter of the projectile and the compressive strength of the target,respectively.展开更多
Burkitt lymphoma is a highly aggressive B-cell neoplasm. New therapeutic methods are needed to overcome the adverse effect of intensive chemotherapy regimens. Valproic acid and (-)-gossypol are two kinds of chemical...Burkitt lymphoma is a highly aggressive B-cell neoplasm. New therapeutic methods are needed to overcome the adverse effect of intensive chemotherapy regimens. Valproic acid and (-)-gossypol are two kinds of chemical compounds used as new anti-tumor drugs in recent years.展开更多
The effect of solvent on surface enhanced Raman scattering [SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent....The effect of solvent on surface enhanced Raman scattering [SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent. The influence of solvent is due to the change of the adsorption quantity and adsorption intensity.展开更多
The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of b...The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of black sea bream stock enhancement.In order to detect the contribution of released individuals in Zhujiang River Estuary(ZRE)and Daya Bay(DB),six microsatellite markers were used to identify the hatchery-released individuals.In addition,this pedigree of hatchery populations(broodfish and hatchery-released offspring)was traced to detect the number of effective parents(N_(e)),the inbreeding coefficient and the decrease of genetic variability in the reproduction.The pedigree reconstruction showed that at least 69(out of 93)broodfish had offspring.The estimated N_(e) was 54.8,consequently the inbreeding coefficient was 0.91%.The genetic diversity of hatchery-released offspring was lower than that in that of broodfish(heterozygosity alleles,0.727-0.774),some alleles(number of alleles,61-69)and genetic variance were lost during reproduction.It was observed that wild samples had higher levels of genetic diversity compared with hatchery populations as well as recaptured samples in releasing area.A total of 128 hatchery-released black sea bream were identified among 487 recaptured samples in ZRE,while a total of 15 samples were identified among 96 samples in DB.In summary,there was a high survival of released fish.N_(e)vertheless,the results provided evidence to consider a loss of genetic variation in hatcheryreleased stock and a negative genetic effect of the stock enhancement.展开更多
Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-po...Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-posable masks will be generated every day in the world,causing great pressure on the environment.Herein,con-ductive polymer composites are fabricated by simple melt blending of mask fragments(mask polypropylene,short for mPP)and multi-walled carbon nanotubes(MWNTs).MWNTs were used as modifiers for composites because of their high strength and high conductivity.The crystalline structure,mechanical,electrical and thermal enhancement effect of the composites were investigated.MWNTs with high thermal stability acted the role of promoting the crystallisation of mPP by expediting the crystalline nucleation,leading to the improvement of amount for crystalline nucleus.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.With 2.0 wt% MWNTs loading,the tensile strength and electrical conductivity of the composites were increased by 809% and 7 orders of magnitude.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.Thus,more conducting paths were constructed to transport carriers.The findings may open a way for high value utilization of the disposable masks.展开更多
Impact experiments of large-caliber PELE with various inner-outer diameter ratio perforating RHA plate at low velocity were performed.Experimental results showed the size of perforated holes on plate,average diameter ...Impact experiments of large-caliber PELE with various inner-outer diameter ratio perforating RHA plate at low velocity were performed.Experimental results showed the size of perforated holes on plate,average diameter of damage area on witness plate,and number of behind-armor fragments will increase as d/D increasing from 0.72 to 0.84.Expansion and fragmentation of large-caliber PELE in this condition were also numerically studied with ANSYS Autodyn.Then,an analytical model accounting for an additional radial shock wave was presented to predict radial expansion velocity and fragmentation of jacket,as well as an empirical approach to estimate diameter of damage area.Calculation results by these approaches were in good agreement with experiments and numerical simulations.Further discussion revealed that Shock/rarefaction wave interactions behavior varying with inner-outer diameter ratio is an important mechanism resulting in different lateral effect by PELE projectiles with various configurations.展开更多
Experimental results of a direct current enhanced inductively coupled plasma(DCE-ICP) source which consists of a typical cylindrical ICP source and a plate-to-grid DC electrode are reported.With the use of this new ...Experimental results of a direct current enhanced inductively coupled plasma(DCE-ICP) source which consists of a typical cylindrical ICP source and a plate-to-grid DC electrode are reported.With the use of this new source,the plasma characteristic parameters,namely,electron density,electron temperature and plasma uniformity,are measured by Langmuir floating double probe.It is found that DC discharge enhances the electron density and decreases the electron temperature,dramatically.Moreover,the plasma uniformity is obviously improved with the operation of DC and radio frequency(RF) hybrid discharge.Furthermore,the nonlinear enhancement effect of electron density with DC?+?RF hybrid discharge is confirmed.The presented observation indicates that the DCE-ICP source provides an effective method to obtain high-density uniform plasma,which is desirable for practical industrial applications.展开更多
The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)^(2-) has been studied. When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0<x<0.21,its photoluminescent spectrum is near to that of Na_5Eu(Mo...The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)^(2-) has been studied. When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0<x<0.21,its photoluminescent spectrum is near to that of Na_5Eu(MoO_4)_4,but its luminescent intensity increases.When x=0.033,the intensity is increased by about 30%.According to the X-ray diffraction analysis,W ions get into the lattice and occupy the sites of the Mo ions.The change of crystal environment of Eu^(3+) may result in the luminescent enhancement.展开更多
基金supported by the National Key R&D Program of China(2016YFF0102003 and 2016YFF0102000).
文摘In this work,a new structure is used to enhance the nonlinear effect in the cavity,which improvesthe performance of the 1.3μm broadband swept source.The swept source adopts a semiconductoroptical amplifier(SOA),a circulator,a coupler,and a tunable filter.In the structure,the lightpasses through the nonlinear medium(SOA)twice in two opposite directions,which excites thenonlinear ffect and increases the performance of the swept source.The tunable filter is based on apolygon rotating mirror and gratings.Traditionally,multiple SOAs are adopted to improve thesweep range and the optical power,which increases the cost and complexity of the swept source.The method proposed in this paper can improve the spectral range and optical power of the sweptsources without additional accessories.For the short-cavity swept source,the power increasesfrom 6 mW to 7.7 mW,and the sweep range increases from 98 nm to 120 nm.The broadband swept sources could have wide applications in biomedical imaging,sensor system,measurementand so on.
基金This work was supported by Hunan Natural Science Foundation of China (No. 05JJ40017) Hunan Education Department of China (Project No. 05B064).
文摘The influence of different concentration of oxalic acid matrix on elemental inductively coupled plasma mass spectrometry (ICP-MS) has been investigated. It has been proved that the sensitivity of analytes can be significantly enhanced by adding small amounts of oxalic acid medium with adjusted nebulizer flow-rate gas, especially for the elements with ionization potential between 9 and 11 eV. Oxalic acid, as an enhancement agent, can be used to compensate the signal depression caused by inorganic matrix and to improve the detection limits about two to eight times, for the hard-to-ionize elements in ICP-MS determination.
基金supported by the National Natural Science Foundation of China under Grant No. G050104011004024the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No. A0901040110018512026
文摘Surface plasmon resonance of noble metal nanoparticles leads to the optical absorption enhancement effects,which have great potential applications in solar cell.By using the general numerical method of discrete dipole approximation (DDA),we study the absorption and scattering properties of two-dimensional square silver nanodisks (2D SSN) arrays on the single crystal silicon solar cell.Based on the effective reflective index model of the single crystal silicon solar cell,we investigate the optical enhancement absorption of light energy by varying the light incident direction,particle size,aspect ratio,and interparticle spacing of the silver nanodisks.The peak values and position of the optical extinction spectra of the 2D square arrays of noble metal nanodisks are obtained with the different array structures.
文摘Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × 4 and a unit frame area of 60 m<sup>2</sup>. A total of 58,201 eggs were collected by 24 monitoring times, of which 30,441 were from Lukou and 27,760 from Hengyang. 3831 fish eggs identify 8 fish species using morphological or molecular biological methods. The results showed that the number of eggs peaked from the 8<sup>th</sup> day to the 24<sup>th</sup> day after the nest entered the water, and then decreased rapidly. There was significant negative correlation between egg number in per m<sup>2</sup> fish nest and days of fish nest (P < 0.01). The economic benefits of artificial fish nests were RMB 11.81 million. The artificial fish nest can not only increase the population of fish, but also has significant economic benefits.
文摘Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
文摘Objective: To observe and assess the efficacy enhancing and toxicity attenuating effect of Nuzhen Yangyin Granule (NYG) to the anti-parkinsonism (paralysis agitans) therapy with medopa and ar-tane. Methods: Adopting the randomized double-blinded method, the effect of adding NYG to 30 patients with Parkinsonism in the treated group,
基金financially supported by the National Natural Science Foundation of China(No.21975163)the Shenzhen Innovative Research Team Program(KQTD20190929173914967)the Senior Talent Research Start-up Fund of Shenzhen University(000265)。
文摘Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide.Herein,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory.The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis performance.The optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.
文摘Enhanced damage to the full-filled fuel tank,impacted by the cold pressed and sintered PTFE/Al/W reactive material projectile(RMP)with a density of 7.8 g/cm3,is investigated experimentally and theoretically.The fuel tank is a rectangular structure,welded by six pieces of 2024 aluminum plate with a thickness of 6 mm,and filled with RP-3 aviation kerosene.Experimental results show that the kerosene is ignited by the RMP impact at a velocity above 1062 m/s,and a novel interior ignition phenomenon which is closely related to the rupture effect of the fuel tank is observed.However,the traditional steel projectile with the same mass and dimension requires a velocity up to 1649 m/s to ignite the kerosene.Based on the experimental results,the radial pressure field is considered to be the main reason for the shear failure of weld.For mechanism considerations,the chemical energy released by the RMP enhances the hydrodynamic ram(HRAM)effect and provides additional ignition sources inside the fuel tank,thereby enhancing both rupture and ignition effects.Moreover,to further understand the enhanced ignition effect of RMP,the reactive debris temperature inside the kerosene is analyzed theoretically.The initiated reactive debris with high temperature provides effective interior ignition sources to ignite the kerosene,resulting in the enhanced ignition of the kerosene.
基金supported by the National Key Research and Development Program of China (No.2019YFA0708800)the Fundamental Research Funds for the Central Universities (No.DUT20ZD101)。
文摘Integral thin shells made of high strength aluminum alloys are urgently needed in new generation transportation equipment. There are challenges to overcoming the co-existing problems of wrinkling and splitting by the cold forming and hot forming processes. An innovative technology of ultra-low temperature forming has been invented for aluminum alloy thin shells by the new phenomenon of ‘dual enhancement effect’. That means plasticity and hardening are enhanced simultaneously at ultra-low temperatures. In this perspective, the dual enhancement effect is described, and the development, current state and prospects of this new forming method are introduced. This innovative method can provide a new approach for integral aluminum alloy components with large size, ultra-thin thickness, and high strength. An integral tank dome of rocket with 2 m in diameter was formed by using a blank sheet with the same thickness as the final component, breaking through the limit value of thickness-diameter ratio.
基金supported by the National Natural Science Foundation of China(21673030)the Fundamental Research Funds for the Central Universities(DUT16QY49)
文摘In terms of the reaction of COreduction to CO with hydrogen, COconversion is very low at low temperature due to the limitation of thermodynamic equilibrium(TE). To overcome this limitation, plasma catalytic reduction of COto CO in a catalyst-filled dielectric barrier discharge(DBD) reactor is studied. An enhanced effect of plasma on the reaction over Au/CeOcatalysts is observed. For both the conventionally catalytic(CC) and plasma catalytic(PC, Pin= 15 W) reactions under conditions of 400 °C, H/CO= 1,200 SCCM, GHSV = 12,000 mL·gcat·h, COconversions over Au/CeOreach 15.4% and 25.5% due to the presence of Au, respectively, however, those over CeOare extremely low and negligible. Moreover,COconversion over Au/CeOin the PC reaction exceeds 22.4% of the TE conversion. Surface intermediate species formed on the catalyst samples during the reactions are determined by in-situ temperatureprogrammed decomposition(TPD) technique. Interestingly, it disclosed that in the PC reaction, the formation of formate intermediate is enhanced by plasma, and the acceleration by plasma in the decomposition of formate species is much greater than that in the formation of formate species on Au/CeO. Enhancement factor is introduced to quantify the enhanced effect of plasma. Lower reactor temperature, higher gas hourly space velocity(GHSV), and lower molar ratio of H/COwould be associated with larger enhancement factor.
文摘The novel fusion proteins harbering human or mouse interferon combined with epidermalgrowth factor receptor binding domain were constructed using methods of genetic and proteinengineering. The fusion proteins were assayed to retain complete antiviral activities. The EGFreceptor binding moiety of the fusion proteins exhibited competitive binding saainst 125 I-EGFfor EGF receptbrs on A431 cells. The fusion proteins were shown to be more potent in in-hibiting the growth of cultured target carcinoma cells than interferon-y alone. Experimentaldata derived from rnouse Bl6 malignant melanoma models indicates that the weight of tumorin mice treated with IFN fusion proteins was significantly smaller than that of mice treatedwith interferon-y alone. The work here is unprecedented in the world and provides a reliableevidence to supPOrt the upcoming clinical employment of a class of interferons that specificallytarget tumor cell
基金Supported by the National Basic Research Program of China(No.2009CB930102)the National High Technology Research and Development Program of China(No.2007AA03Z535)+3 种基金the National Natural Science Foundation of China(No.21004062)the China-Japan-Korea Foresight Program(No.20621140369)"100 Talents Program" of the Chinese Academy of Sciences(No.KGCX2- YW-802) the Project of Jilin Provincial Science & Technology Department,China(No.200705110)
文摘Enhanced permeation and retention(EPR) targeting effect of rhodamine B labeled PEG-b-P(LA-co-DHP) [PEG:poly(ethylene glycol);LA:L-lactide;DHP:2,2-dihydroxylmethyl-propylene carbonate] micelles(RhB-micelles) was observed in H22 liver cancer bearing mice.The RhB-micelles were prepared by conjugating rhodamine B with the DHP units of amphiphilic block copolymer PEG-b-P(LA-co-DHP) followed by subsequent self-assembling of the conjugate.The parent copolymer PEG-b-P(LA-co-DHP) was synthesized by ring-opening copolymerization of LA and DHP with PEG as macroinitiator and diethyl zinc(ZnEt2) as catalyst.The micelles have a spherical shape and the average diameter is ca.50 nm by TEM(transmission electron microscope) or 80 nm by DLS(dynamic light scattering).Their in vitro cell uptake experiment by CLSM(confocal laser scanning microscopy) and flow cytometry showed preferential internalization of micelles by MCF-7 human breast cancer cells to free RhB.The in vivo tests by live animal imaging and ex vivo excised organ imaging showed that after vena tail injection,free RhB molecules were distributed in the whole body through the circulation system and then gradually metabolized and excreted and there was no preferential partition in tumor bed from the beginning to the end.But the RhB-micelles were preferentially distributed to the tumor bed so that their concentration(fluorescent intensity) in tumor bed got the level of the liver at a certain time point between 1 and 6 h and reached a maximum relative intensity at around 12 h,indicating an obvious EPR effect of RhB-micelles in H22 liver cancer.
基金supported by the National Natural Science Foundation of China (Grant No: 11472008, 11772160, 11802141)the Opening Project of State Key Laboratory of Explosion Science and Technology (KFJJ18-01M), Beijing Institute of Technology。
文摘When a penetrator with enhanced lateral effect(PELE) impacts on a reinforced concrete(RC) target,the target is damaged with a large opening.An understanding of how PELE projectile parameters affect the opening dimension,is essential for effective design of the PELE projectile.In this study,under the condition that the impact velocity and target parameters(strength and thickness) were fixed values,the important influence factors of the PELE(jacket wall thickness B,jacket material strength Y1,filling material strength Y2 and angle of monolithic jacket θ) were determined by a dimensional analysis.Tests and simulations of the PELE penetrating the RC target were conducted to analyze the influence of these factors on opening diameter(D,an equivalent diameter under relative kinetic energy).Based on the test and simulation results,it is found that the influence of these factors B,Y1 and θ on the deformation mode of the jacket shows a similar trend:as values of the three factors decrease,the jacket deforms from small bending deformation to large one,and then to curling deformation.This causes the opening diameter to first increase with the decrease of these three factors,and then decreases.It is well known that the bending resistance of the jacket is related to these factors B,Y1 and θ.Therefore,a plastic limit bending moment(M0) of the jacket was quoted to characterize the influence of these factors on the bending deformation of the jacket and the opening diameter of the target.The influence factor Y2 causes D to first increase with the increase of Y2,and then decreases.A formula was developed to predict the opening diameter,whose influence parameters were considered in a dimensionless way.It has been shown that the dimensionless opening diameter D/d1 is dependent on two dimensionless parameters■ and■,where d1 and fc are the outer diameter of the projectile and the compressive strength of the target,respectively.
基金supported by the National Natural Science Foundation of China(81170467 and 81270569)Major Project of PLA Medical S&T foundation(AWS11C004)Medical Science Research Foundation of Chongqing Health and Family Planning Committee(2015MSXM224)
文摘Burkitt lymphoma is a highly aggressive B-cell neoplasm. New therapeutic methods are needed to overcome the adverse effect of intensive chemotherapy regimens. Valproic acid and (-)-gossypol are two kinds of chemical compounds used as new anti-tumor drugs in recent years.
文摘The effect of solvent on surface enhanced Raman scattering [SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent. The influence of solvent is due to the change of the adsorption quantity and adsorption intensity.
基金The Science and Technology Project of Guangdong Province under contract No.2019B121201001the National Key R&D Program of China under contract No.2019YFD0901301+3 种基金the Fund of China-Vietnam Joint Survey on Fish Stocks in the Common Fishing Zone of the Beibu Gulfthe Central Public-interest Scientific Institution Basal Research Fund,South China Sea Fisheries Research Institute,Chinese Academy of Fishery Science under contract No.2021SD14the China-ASEAN Maritime Cooperation Fund(China-Vietnam Fishery Stock Enhancement and Conservation in Beibu Gulf)the Hainan Provincial Natural Science Foundation of China under contract No.320QN358.
文摘The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of black sea bream stock enhancement.In order to detect the contribution of released individuals in Zhujiang River Estuary(ZRE)and Daya Bay(DB),six microsatellite markers were used to identify the hatchery-released individuals.In addition,this pedigree of hatchery populations(broodfish and hatchery-released offspring)was traced to detect the number of effective parents(N_(e)),the inbreeding coefficient and the decrease of genetic variability in the reproduction.The pedigree reconstruction showed that at least 69(out of 93)broodfish had offspring.The estimated N_(e) was 54.8,consequently the inbreeding coefficient was 0.91%.The genetic diversity of hatchery-released offspring was lower than that in that of broodfish(heterozygosity alleles,0.727-0.774),some alleles(number of alleles,61-69)and genetic variance were lost during reproduction.It was observed that wild samples had higher levels of genetic diversity compared with hatchery populations as well as recaptured samples in releasing area.A total of 128 hatchery-released black sea bream were identified among 487 recaptured samples in ZRE,while a total of 15 samples were identified among 96 samples in DB.In summary,there was a high survival of released fish.N_(e)vertheless,the results provided evidence to consider a loss of genetic variation in hatcheryreleased stock and a negative genetic effect of the stock enhancement.
基金M.Xiang and S.Dong wishes to thank the National Natural Science Foundation of China(21908086 and 51801083)Changzhou Sci&Tech Program(CJ20190035)+1 种基金Jiangsu Higher Education Institutions in China(19KJB610011)Natural Science Foundation of Jiangsu Province(BK20181044).
文摘Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-posable masks will be generated every day in the world,causing great pressure on the environment.Herein,con-ductive polymer composites are fabricated by simple melt blending of mask fragments(mask polypropylene,short for mPP)and multi-walled carbon nanotubes(MWNTs).MWNTs were used as modifiers for composites because of their high strength and high conductivity.The crystalline structure,mechanical,electrical and thermal enhancement effect of the composites were investigated.MWNTs with high thermal stability acted the role of promoting the crystallisation of mPP by expediting the crystalline nucleation,leading to the improvement of amount for crystalline nucleus.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.With 2.0 wt% MWNTs loading,the tensile strength and electrical conductivity of the composites were increased by 809% and 7 orders of magnitude.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.Thus,more conducting paths were constructed to transport carriers.The findings may open a way for high value utilization of the disposable masks.
文摘Impact experiments of large-caliber PELE with various inner-outer diameter ratio perforating RHA plate at low velocity were performed.Experimental results showed the size of perforated holes on plate,average diameter of damage area on witness plate,and number of behind-armor fragments will increase as d/D increasing from 0.72 to 0.84.Expansion and fragmentation of large-caliber PELE in this condition were also numerically studied with ANSYS Autodyn.Then,an analytical model accounting for an additional radial shock wave was presented to predict radial expansion velocity and fragmentation of jacket,as well as an empirical approach to estimate diameter of damage area.Calculation results by these approaches were in good agreement with experiments and numerical simulations.Further discussion revealed that Shock/rarefaction wave interactions behavior varying with inner-outer diameter ratio is an important mechanism resulting in different lateral effect by PELE projectiles with various configurations.
基金supported by National Natural Science Foundation of China (Grant No.11475038.)
文摘Experimental results of a direct current enhanced inductively coupled plasma(DCE-ICP) source which consists of a typical cylindrical ICP source and a plate-to-grid DC electrode are reported.With the use of this new source,the plasma characteristic parameters,namely,electron density,electron temperature and plasma uniformity,are measured by Langmuir floating double probe.It is found that DC discharge enhances the electron density and decreases the electron temperature,dramatically.Moreover,the plasma uniformity is obviously improved with the operation of DC and radio frequency(RF) hybrid discharge.Furthermore,the nonlinear enhancement effect of electron density with DC?+?RF hybrid discharge is confirmed.The presented observation indicates that the DCE-ICP source provides an effective method to obtain high-density uniform plasma,which is desirable for practical industrial applications.
文摘The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)^(2-) has been studied. When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0<x<0.21,its photoluminescent spectrum is near to that of Na_5Eu(MoO_4)_4,but its luminescent intensity increases.When x=0.033,the intensity is increased by about 30%.According to the X-ray diffraction analysis,W ions get into the lattice and occupy the sites of the Mo ions.The change of crystal environment of Eu^(3+) may result in the luminescent enhancement.