A rat model of cerebral ischemia/reperfusion was established by suture occlusion of the left middle cerebral artery. In situ hybridization results showed that the number of brain-derived neurotrophic factor mRNA-posit...A rat model of cerebral ischemia/reperfusion was established by suture occlusion of the left middle cerebral artery. In situ hybridization results showed that the number of brain-derived neurotrophic factor mRNA-positive cells in the ischemic rat cerebral cortex increased after cerebral ischemia/ reperfusion injury. Low frequency continuous wave electroacupuncture （frequency 2-6 Hz, current intensity 2 mA） stimulation of the brachial plexus trunk on the healthy （right） side increased the number of brain-derived neurotrophic factor mRNA-positive cells in the ischemic cerebral cortex 14 days after cerebral ischemia/reperfusion injury. At the same time, electroacupuncture stimulation of the healthy brachial plexus truck significantly decreased neurological function scores and alleviated neurological function deficits. These findings suggest that electroacupuncture stimulation of the brachial plexus trunk on the healthy （right） side can greatly increase brain-derived neurotrophic factor mRNA expression and improve neurological function.展开更多
To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics...To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics of CoAl LDH were investigated by transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectric spectroscopy(XPS),Brunauer–Emmett–Telle(BET),atomic force microscopy(AFM)and zeta potential.Due to their large specific surface area and abundant hydroxyl groups,CoAl LDH nanosheets exhibit good humidity sensing performance.In a range of 11.3%and 97.6%relative humidity(RH),the sensor behaved an ultrahigh sensitivity(127.8 Hz/%RH),fast response(9.1 s)and recovery time(3.1 s),low hysteresis(3.1%RH),good linearity(R^(2)=0.9993),stability and selectivity.Besides,the sensor can recover the initial response frequency after being wetted by deionized water,revealing superior self-recovery ability under high humidity.Based on in-situ Fourier transform infrared spectroscopy(FT-IR),the adsorption mechanism of CoAl LDH toward water molecules was explored.The QCM sensor can distinguish different respiratory states of people and wetting degree of fingers,as well as monitor the humidity in vegetable packaging,suggesting excellent properties and a promising application in humidity sensing.展开更多
Many multicomponent concentrated solid solution alloys(CSAs),including high-entropy alloys(HEAs),exhibit improved radiation resistance and enhanced structural stability in harsh environments.To study and assess irradi...Many multicomponent concentrated solid solution alloys(CSAs),including high-entropy alloys(HEAs),exhibit improved radiation resistance and enhanced structural stability in harsh environments.To study and assess irradiation resistance of nuclear materials,energetic ion and electron beams are commonly used to create displacement damage.Moreover,charged particles of ions,electrons,and positrons are unique tools to create and characterize radiation effects.Ion beam analysis(e.g.,Rutherford backscattering spectrometry,nuclear reaction analysis,and time-of-flight elastic recoil detection analysis),electron microscopy techniques(e.g.,transmission or scanning electron microscopy,and electron diffraction),and positron annihilation spectroscopy have been applied to characterize irradiated CSAs or HEAs to understand defect formation and evolution together with chemical and microstructural information.Their distinctive analyzing power and some perspectives in these techniques are reviewed.In developing structural alloys desirable for applications in advanced reactors,neutron exposure is a critical test but the limitation in achievable high damage levels is,however,a bottleneck.Ion irradiation is often used as a surrogate for neutron irradiation,and the associated reduced transmutations and higher displacements per atom(dpa)rates are desirable for materials research.Nevertheless,cautions need to be taken when relying on ion irradiation results for reactor evaluations.Literature on differences between ions and neutrons is briefly reviewed.In addition,the links to bridge the current advances on fundamental understandings to reactor applications are discussed to lay the groundwork between neutrons and ions for radiation effects studies.展开更多
The effect of the main-panel angle of a single-slotted cambered otter-board was investigated using engineering models in a wind tunnel.Three different angles(0,6,and 12)were evaluated at a wind speed of 28 m/s.Para...The effect of the main-panel angle of a single-slotted cambered otter-board was investigated using engineering models in a wind tunnel.Three different angles(0,6,and 12)were evaluated at a wind speed of 28 m/s.Parameters measured included:drag coefficient Cx,lift coefficient Cy,pitch moment coefficient Cm,center of pressure coefficient Cp,and the liftedrag ratio Cy/Cx,over a range of angle of attack(0e70).These coefficients were used in analyzing the differences in the performance among the three otter-board models.Results showed that the maximum lift coefficient Cy of the otter-board model with a main-panel angle of 0was highest(1.875 at a¼25).However,when the angle of attack was smaller(0<a<22.5),the lift coefficient of the otter-board increased as the angle of the main-panel increased.The maximum Cy/Cx of the otter-board with a main-panel angle of 12was highest(7.417 at a¼2.5),and the liftedrag ratio increased when the angle of the main-panel increased within the angle of attack at small angles(0<a<12.5).A comparative analysis of Cm and Cp showed that the stability of the otter-board with a main-panel angle of 0is better than those of the other models.Therefore,the comparative analysis of Cm and Cp,shows that a larger angle of the main-panel can reduce the stability of single-slotted otter-board.The findings of this study offer useful reference data for the structural optimization of otter-boards for trawling。展开更多
Lithium-sulfur(Li-S)batteries as power supply systems possessing a theoretical energy density of as high as 2600 Wh kg−1 are considered promising alternatives toward the currently used lithium-ion batteries(LIBs).Howe...Lithium-sulfur(Li-S)batteries as power supply systems possessing a theoretical energy density of as high as 2600 Wh kg−1 are considered promising alternatives toward the currently used lithium-ion batteries(LIBs).However,the insulation characteristic and huge volume change of sulfur,the generation of dissolvable lithium polysulfides(LiPSs)during charge/discharge,and the uncontrollable dendrite formation of Li metal anodes render Li-S batteries serious cycling issues with rapid capacity decay.To address these challenges,extensive efforts are devoted to designing cathode/anode hosts and/or modifying separators by incorporating functional materials with the features of improved conductivity,lithiophilic,physical/chemical capture ability toward LiPSs,and/or efficient catalytic conversion of LiPSs.Among all candidates,molybdenum-based(Mo-based)materials are highly preferred for their tunable crystal structure,adjustable composition,variable valence of Mo centers,and strong interactions with soluble LiPSs.Herein,the latest advances in design and application of Mo-based materials for Li-S batteries are comprehensively reviewed,covering molybdenum oxides,molybdenum dichalcogenides,molybdenum nitrides,molybdenum carbides,molybdenum phosphides,and molybdenum metal.In the end,the existing challenges in this research field are elaborately discussed.展开更多
Purse seiners deploy large amounts of drifting fish aggregation devices(FADs)in all tropical oceans to catch tunas.These FADs are constructed with porous synthetic fibre netting,which are responsible for incidental mo...Purse seiners deploy large amounts of drifting fish aggregation devices(FADs)in all tropical oceans to catch tunas.These FADs are constructed with porous synthetic fibre netting,which are responsible for incidental mortality of sea turtles and sharks through entanglement,and can engage in ghost fishing if they are lost and abandoned.The use of natural or biodegradable materials to build FADs can effectively mitigate marine pollution and bycatch issues,and as such they are currently promoted by fisheries management organizations.This study evaluated the degradability of ropes made of common natural fibres;cotton rope(3-strand,96-thread,twisted,S-lay),jute rope(3-strand,13-thread,twisted,Z-lay)and sisal rope(3-strand,8-thread,twisted,Z-lay).Degradability was evaluated by measuring the breaking strength(cN/dtex)and retention ratio of rupture elongation.Results showed that jute rope and sisal rope experienced rapid reduction of strength which over the first month soaking in the sea fell by 66.8%and 46.9%,respectively.Cotton rope exhibited the most inert degradation behavior,with breaking strength maintained at half of the initial value at 10 months.The retention ratio of rupture elongation for jute ropes and sisal ropes fluctuated considerably in the following months after deployment,compared to the relatively stable change for cotton rope.Results suggested that among these congeners,cotton rope would be most preferable component for Bio-FADs with a 10-month minimum durability that matches the required lifetime of FAD fishing strategies.展开更多
The effect of vinyltrimethoxysilane(VTMS)graft and SiO_(2) on the structure and mechanical properties of silane-grafted-polyethylene/SiO_(2)(VTMS-g-PE/SiO_(2))nanocomposite fibers and ropes was studied.Scanning electr...The effect of vinyltrimethoxysilane(VTMS)graft and SiO_(2) on the structure and mechanical properties of silane-grafted-polyethylene/SiO_(2)(VTMS-g-PE/SiO_(2))nanocomposite fibers and ropes was studied.Scanning electron microscopy(SEM),Fourier transfer infrared(FT-IR),differential scanning calorimetry analysis(DSC)and tensile mechanical tests were performed to characterize the morphology,thermal and mechanical properties of nanocomposite fibers and ropes.The results revealed that the SiO_(2) nanoparticles were well dispersed throughout the polymeric matrix.With increasing SiO_(2) content,T_(m),the melt peak width and X_(c),degree of crystallinity,of VTMS-g-PE/SiO_(2) nanocomposite fibers increased.The breaking load and breaking strength of the nanocomposite fiber ropes were remarkably improved compared to pure PE fiber ropes and elongation at break was also decreased.展开更多
基金supported by the National Science &Technology Pillar Program in the Eleventh Five-year Plan Period, No. 2006BAl01A00a grant from Science and Technology Department of Shandong Province, No. 22130109a grant from Science and Technology Bureau of Qingdao City, No. Kzd-03,09-1-1-33-nsh
文摘A rat model of cerebral ischemia/reperfusion was established by suture occlusion of the left middle cerebral artery. In situ hybridization results showed that the number of brain-derived neurotrophic factor mRNA-positive cells in the ischemic rat cerebral cortex increased after cerebral ischemia/ reperfusion injury. Low frequency continuous wave electroacupuncture （frequency 2-6 Hz, current intensity 2 mA） stimulation of the brachial plexus trunk on the healthy （right） side increased the number of brain-derived neurotrophic factor mRNA-positive cells in the ischemic cerebral cortex 14 days after cerebral ischemia/reperfusion injury. At the same time, electroacupuncture stimulation of the healthy brachial plexus truck significantly decreased neurological function scores and alleviated neurological function deficits. These findings suggest that electroacupuncture stimulation of the brachial plexus trunk on the healthy （right） side can greatly increase brain-derived neurotrophic factor mRNA expression and improve neurological function.
基金supported by the Shanghai Natural Science Foundation(No.21ZR1427500)the Agricultural Project of Shanghai Science and Technology Innovation Action Plan(No.19391901600).
文摘To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics of CoAl LDH were investigated by transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectric spectroscopy(XPS),Brunauer–Emmett–Telle(BET),atomic force microscopy(AFM)and zeta potential.Due to their large specific surface area and abundant hydroxyl groups,CoAl LDH nanosheets exhibit good humidity sensing performance.In a range of 11.3%and 97.6%relative humidity(RH),the sensor behaved an ultrahigh sensitivity(127.8 Hz/%RH),fast response(9.1 s)and recovery time(3.1 s),low hysteresis(3.1%RH),good linearity(R^(2)=0.9993),stability and selectivity.Besides,the sensor can recover the initial response frequency after being wetted by deionized water,revealing superior self-recovery ability under high humidity.Based on in-situ Fourier transform infrared spectroscopy(FT-IR),the adsorption mechanism of CoAl LDH toward water molecules was explored.The QCM sensor can distinguish different respiratory states of people and wetting degree of fingers,as well as monitor the humidity in vegetable packaging,suggesting excellent properties and a promising application in humidity sensing.
基金supported as part of Energy Dissipation to Defect Evolution(EDDE)an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,under contract number DE-AC05-00OR22725.
文摘Many multicomponent concentrated solid solution alloys(CSAs),including high-entropy alloys(HEAs),exhibit improved radiation resistance and enhanced structural stability in harsh environments.To study and assess irradiation resistance of nuclear materials,energetic ion and electron beams are commonly used to create displacement damage.Moreover,charged particles of ions,electrons,and positrons are unique tools to create and characterize radiation effects.Ion beam analysis(e.g.,Rutherford backscattering spectrometry,nuclear reaction analysis,and time-of-flight elastic recoil detection analysis),electron microscopy techniques(e.g.,transmission or scanning electron microscopy,and electron diffraction),and positron annihilation spectroscopy have been applied to characterize irradiated CSAs or HEAs to understand defect formation and evolution together with chemical and microstructural information.Their distinctive analyzing power and some perspectives in these techniques are reviewed.In developing structural alloys desirable for applications in advanced reactors,neutron exposure is a critical test but the limitation in achievable high damage levels is,however,a bottleneck.Ion irradiation is often used as a surrogate for neutron irradiation,and the associated reduced transmutations and higher displacements per atom(dpa)rates are desirable for materials research.Nevertheless,cautions need to be taken when relying on ion irradiation results for reactor evaluations.Literature on differences between ions and neutrons is briefly reviewed.In addition,the links to bridge the current advances on fundamental understandings to reactor applications are discussed to lay the groundwork between neutrons and ions for radiation effects studies.
基金This work is financially supported by the National Key Technology R&D Program(Grant No.2013BAD13B03).
文摘The effect of the main-panel angle of a single-slotted cambered otter-board was investigated using engineering models in a wind tunnel.Three different angles(0,6,and 12)were evaluated at a wind speed of 28 m/s.Parameters measured included:drag coefficient Cx,lift coefficient Cy,pitch moment coefficient Cm,center of pressure coefficient Cp,and the liftedrag ratio Cy/Cx,over a range of angle of attack(0e70).These coefficients were used in analyzing the differences in the performance among the three otter-board models.Results showed that the maximum lift coefficient Cy of the otter-board model with a main-panel angle of 0was highest(1.875 at a¼25).However,when the angle of attack was smaller(0<a<22.5),the lift coefficient of the otter-board increased as the angle of the main-panel increased.The maximum Cy/Cx of the otter-board with a main-panel angle of 12was highest(7.417 at a¼2.5),and the liftedrag ratio increased when the angle of the main-panel increased within the angle of attack at small angles(0<a<12.5).A comparative analysis of Cm and Cp showed that the stability of the otter-board with a main-panel angle of 0is better than those of the other models.Therefore,the comparative analysis of Cm and Cp,shows that a larger angle of the main-panel can reduce the stability of single-slotted otter-board.The findings of this study offer useful reference data for the structural optimization of otter-boards for trawling。
基金supported by the National Natural Science Foundation of China(Nos.21975123 and 61704076)the Natural Science Basic Research Program of Shaanxi(No.2020JM-092)+2 种基金the Six Talent Peaks Project in Jiangsu Prov-ince(No.XCL-024)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Nos.KYCX20_0997 and SJCX20_0401)the Fundamental Research Funds for the Central Universities.
文摘Lithium-sulfur(Li-S)batteries as power supply systems possessing a theoretical energy density of as high as 2600 Wh kg−1 are considered promising alternatives toward the currently used lithium-ion batteries(LIBs).However,the insulation characteristic and huge volume change of sulfur,the generation of dissolvable lithium polysulfides(LiPSs)during charge/discharge,and the uncontrollable dendrite formation of Li metal anodes render Li-S batteries serious cycling issues with rapid capacity decay.To address these challenges,extensive efforts are devoted to designing cathode/anode hosts and/or modifying separators by incorporating functional materials with the features of improved conductivity,lithiophilic,physical/chemical capture ability toward LiPSs,and/or efficient catalytic conversion of LiPSs.Among all candidates,molybdenum-based(Mo-based)materials are highly preferred for their tunable crystal structure,adjustable composition,variable valence of Mo centers,and strong interactions with soluble LiPSs.Herein,the latest advances in design and application of Mo-based materials for Li-S batteries are comprehensively reviewed,covering molybdenum oxides,molybdenum dichalcogenides,molybdenum nitrides,molybdenum carbides,molybdenum phosphides,and molybdenum metal.In the end,the existing challenges in this research field are elaborately discussed.
基金support by National Key R&D Program of China(No.2019YFD0901502)National Natural Science Foundation of China(No.41806110,31972844 and 31902426)Shanghai Sailing Program(19YF1419800).
文摘Purse seiners deploy large amounts of drifting fish aggregation devices(FADs)in all tropical oceans to catch tunas.These FADs are constructed with porous synthetic fibre netting,which are responsible for incidental mortality of sea turtles and sharks through entanglement,and can engage in ghost fishing if they are lost and abandoned.The use of natural or biodegradable materials to build FADs can effectively mitigate marine pollution and bycatch issues,and as such they are currently promoted by fisheries management organizations.This study evaluated the degradability of ropes made of common natural fibres;cotton rope(3-strand,96-thread,twisted,S-lay),jute rope(3-strand,13-thread,twisted,Z-lay)and sisal rope(3-strand,8-thread,twisted,Z-lay).Degradability was evaluated by measuring the breaking strength(cN/dtex)and retention ratio of rupture elongation.Results showed that jute rope and sisal rope experienced rapid reduction of strength which over the first month soaking in the sea fell by 66.8%and 46.9%,respectively.Cotton rope exhibited the most inert degradation behavior,with breaking strength maintained at half of the initial value at 10 months.The retention ratio of rupture elongation for jute ropes and sisal ropes fluctuated considerably in the following months after deployment,compared to the relatively stable change for cotton rope.Results suggested that among these congeners,cotton rope would be most preferable component for Bio-FADs with a 10-month minimum durability that matches the required lifetime of FAD fishing strategies.
基金This work was supported by the National Natural Science Foundation of China(Grant No.31502213)Special Scientific Research Funds for Central Non-profit Institutes(East China Sea Fisheries Research Institute)(Grant No.2015T01)the National Key Technology R&D Program(Grant No.2013BAD13B02).
文摘The effect of vinyltrimethoxysilane(VTMS)graft and SiO_(2) on the structure and mechanical properties of silane-grafted-polyethylene/SiO_(2)(VTMS-g-PE/SiO_(2))nanocomposite fibers and ropes was studied.Scanning electron microscopy(SEM),Fourier transfer infrared(FT-IR),differential scanning calorimetry analysis(DSC)and tensile mechanical tests were performed to characterize the morphology,thermal and mechanical properties of nanocomposite fibers and ropes.The results revealed that the SiO_(2) nanoparticles were well dispersed throughout the polymeric matrix.With increasing SiO_(2) content,T_(m),the melt peak width and X_(c),degree of crystallinity,of VTMS-g-PE/SiO_(2) nanocomposite fibers increased.The breaking load and breaking strength of the nanocomposite fiber ropes were remarkably improved compared to pure PE fiber ropes and elongation at break was also decreased.
