Al2O3-Ni interface formed under vacuum condition is non-wetting and weak. Severe instantaneous intedecial reaction (i.e. wetting) at the Al2O3-Ni interface promoted by oxygen can create a strengthened interface. The N...Al2O3-Ni interface formed under vacuum condition is non-wetting and weak. Severe instantaneous intedecial reaction (i.e. wetting) at the Al2O3-Ni interface promoted by oxygen can create a strengthened interface. The NiAl2O4 spinel-Ni intedece is weak and growth of the spinel interphase is detrimental to the Al2O3-Ni intedecial bonding. A proper control of the oxygen partial pressure can achieve wetting while avoiding the existence of spinel at the interface, producing stronger interfaces by both mechanical interlocking and more intimate chemical bonding in an Al2O3-20 vol pct Ni composite.展开更多
Current-voltage electrical characteristics of Er silicide/Si（001） nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on...Current-voltage electrical characteristics of Er silicide/Si（001） nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on Si（001）,a silver wetting layer is evaporated onto the substrate surface kept at room temperature with Er Si2 nanoislands already existing. The effects of the silver layer on the current-voltage characteristics of nanocontacts are discussed.Our experimental results reveal that the silver layer at coverage of 0.4–0.7 monolayer can suppress effectively the current contribution from the surface conduction path. After the surface leakage path of nanocontacts is obstructed, the ideality factor and the Schottky barrier height are determined using the thermionic emission theory, about 2 and 0.5 eV, respectively. The approach adopted here could shed light on the intrinsic transport properties of metal-semiconductor nanocontacts.展开更多
Heat exhaustion is a prevalent heat-related illness among firefighters,posing a severe threat to life without timely intervention.However,current firefighter garments are limited by their singular functionality and ca...Heat exhaustion is a prevalent heat-related illness among firefighters,posing a severe threat to life without timely intervention.However,current firefighter garments are limited by their singular functionality and cannot collect or analyze body fluid during rescue missions.Here,we introduce a wetting gradient effect assisted ultrasensitive meta-garment that incorporates multi-signal biomonitoring,offering an early warning system for heat exhaustion risk.This design enables real-time detection of heart rate,pH value,and the concentrations of glucose,sodium,and potassium in sweat.Benefiting from the surface energy difference,gradient wettability surfaces can be formed,allowing for precise point-to-point fluid control and regulation.Thus,the biosensing fibers require the lowest detection volume(0.1μL)and fastest response time(1.4 s)reported to date.This innovative garment provides a practical solution for early health warning based on abnormal multi-biomarker changes,representing a significant advancement in firefighter safety.展开更多
Biological soil crusts （BSCs） are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss...Biological soil crusts （BSCs） are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss crusts and algae crusts, were selected from a revegetated sandy area of the Tengger Desert in northern China, and the experiment was carried out over a 3-year period from January 2010 to November 2012. We obtained the effec- tive active wetting time to maintain the physiological activity of BSCs basing on continuous field measurements and previous laboratory studies on BSCs photosynthesis and respiration rates. And then we developed a BSCs carbon fixation model that is driven by soil moisture. The results indicated that moss crusts and algae crusts had significant effects on soil moisture and temperature dynamics by decreasing rainfall infiltration. The mean carbon fixation rates of moss and algae crusts were 0.21 and 0.13 g C/（m2.d）, respectively. The annual carbon fixations of moss crusts and algae crusts were 64.9 and 38.6 g C/（m2.a）, respectively, and the carbon fixation of non-rainfall water reached 11.6 g C/（m2.a） （30.2% of the total） and 8.8 g C/（m2.a） （43.6% of the total）, respectively. Finally, the model was tested and verified with continuous field observations. The data of the modeled and measured CO2 fluxes matched notably well. In desert regions, the carbon fixation is higher with high-frequency rainfall even the total amount of seasonal rainfall was the same.展开更多
We provide the capillary pressure curves p_(c)(s)as a function of the effective saturation s based on the theoretical framework of upscaling unsaturated flows in vertically heterogeneous porous layers proposed recentl...We provide the capillary pressure curves p_(c)(s)as a function of the effective saturation s based on the theoretical framework of upscaling unsaturated flows in vertically heterogeneous porous layers proposed recently(Z.Zheng,Journal of Fluid Mechanics,950,A17,2022).Based on the assumption of vertical gravitational-capillary equilibrium,the saturation distribution and profile shape of the invading fluid can be obtained by solving a nonlinear integral-differential equation.The capillary pressure curves p_(c)(s)can then be constructed by systematically varying the injection rate.Together with the relative permeability curves k_(rn)(s)that are already obtained.One can now provide quick estimates on the overall behaviours of interfacial and unsaturated flows in vertically-heterogeneous porous layers.展开更多
文摘Al2O3-Ni interface formed under vacuum condition is non-wetting and weak. Severe instantaneous intedecial reaction (i.e. wetting) at the Al2O3-Ni interface promoted by oxygen can create a strengthened interface. The NiAl2O4 spinel-Ni intedece is weak and growth of the spinel interphase is detrimental to the Al2O3-Ni intedecial bonding. A proper control of the oxygen partial pressure can achieve wetting while avoiding the existence of spinel at the interface, producing stronger interfaces by both mechanical interlocking and more intimate chemical bonding in an Al2O3-20 vol pct Ni composite.
基金Supported by the National Natural Science Foundation of China under Grant No 11374058
文摘Current-voltage electrical characteristics of Er silicide/Si（001） nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on Si（001）,a silver wetting layer is evaporated onto the substrate surface kept at room temperature with Er Si2 nanoislands already existing. The effects of the silver layer on the current-voltage characteristics of nanocontacts are discussed.Our experimental results reveal that the silver layer at coverage of 0.4–0.7 monolayer can suppress effectively the current contribution from the surface conduction path. After the surface leakage path of nanocontacts is obstructed, the ideality factor and the Schottky barrier height are determined using the thermionic emission theory, about 2 and 0.5 eV, respectively. The approach adopted here could shed light on the intrinsic transport properties of metal-semiconductor nanocontacts.
基金supported by the National Key Research and Development Program(2022YFB3805800)National Natural Science Foundation of China(52473307,22208178,62301290)+8 种基金Taishan Scholar Program of Shandong Province in China(tsqn202211116)Shandong Provincial Universities Youth Innovation Technology Plan Team(2023KJ223)Natural Science Foundation of Shandong Province of China(ZR2023YQ037,ZR2020QE074,ZR2023QE043,ZR2022QE174)Shandong Province Science and Technology Small and Medium sized Enterprise Innovation Ability Enhancement Project(2023TSGC0344,2023TSGC1006)Natural Science Foundation of Qingdao(23-2-1-249-zyyd-jch,24-4-4-zrjj-56-jch)Anhui Province Postdoctoral Researcher Research Activity Funding Project(2023B706)Qingdao Key Technology Research and Industrialization Demonstration Projects(23-1-7-zdfn-2-hz)Qingdao Shinan District Science and Technology Plan Project(2022-3-005-DZ)Suqian Key Research and Development Plan(H202310)。
文摘Heat exhaustion is a prevalent heat-related illness among firefighters,posing a severe threat to life without timely intervention.However,current firefighter garments are limited by their singular functionality and cannot collect or analyze body fluid during rescue missions.Here,we introduce a wetting gradient effect assisted ultrasensitive meta-garment that incorporates multi-signal biomonitoring,offering an early warning system for heat exhaustion risk.This design enables real-time detection of heart rate,pH value,and the concentrations of glucose,sodium,and potassium in sweat.Benefiting from the surface energy difference,gradient wettability surfaces can be formed,allowing for precise point-to-point fluid control and regulation.Thus,the biosensing fibers require the lowest detection volume(0.1μL)and fastest response time(1.4 s)reported to date.This innovative garment provides a practical solution for early health warning based on abnormal multi-biomarker changes,representing a significant advancement in firefighter safety.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-EW-301-3)the National Program on Key Basic Research Project (2013CB429905)+1 种基金the National Natural Scientific Foundation of China (41201084 31170385)
文摘Biological soil crusts （BSCs） are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss crusts and algae crusts, were selected from a revegetated sandy area of the Tengger Desert in northern China, and the experiment was carried out over a 3-year period from January 2010 to November 2012. We obtained the effec- tive active wetting time to maintain the physiological activity of BSCs basing on continuous field measurements and previous laboratory studies on BSCs photosynthesis and respiration rates. And then we developed a BSCs carbon fixation model that is driven by soil moisture. The results indicated that moss crusts and algae crusts had significant effects on soil moisture and temperature dynamics by decreasing rainfall infiltration. The mean carbon fixation rates of moss and algae crusts were 0.21 and 0.13 g C/（m2.d）, respectively. The annual carbon fixations of moss crusts and algae crusts were 64.9 and 38.6 g C/（m2.a）, respectively, and the carbon fixation of non-rainfall water reached 11.6 g C/（m2.a） （30.2% of the total） and 8.8 g C/（m2.a） （43.6% of the total）, respectively. Finally, the model was tested and verified with continuous field observations. The data of the modeled and measured CO2 fluxes matched notably well. In desert regions, the carbon fixation is higher with high-frequency rainfall even the total amount of seasonal rainfall was the same.
基金by the Program for Professor of Special Appointment(Eastern Scholar,No.TP2020009)at Shanghai Institutions of Higher Learning。
文摘We provide the capillary pressure curves p_(c)(s)as a function of the effective saturation s based on the theoretical framework of upscaling unsaturated flows in vertically heterogeneous porous layers proposed recently(Z.Zheng,Journal of Fluid Mechanics,950,A17,2022).Based on the assumption of vertical gravitational-capillary equilibrium,the saturation distribution and profile shape of the invading fluid can be obtained by solving a nonlinear integral-differential equation.The capillary pressure curves p_(c)(s)can then be constructed by systematically varying the injection rate.Together with the relative permeability curves k_(rn)(s)that are already obtained.One can now provide quick estimates on the overall behaviours of interfacial and unsaturated flows in vertically-heterogeneous porous layers.
