<正>According to the piezoelectric equation and the vibration theory of the quartz crystal,the relations between the vibrating frequency and structural parameters under the thickness-shear-vibration of AT-cut qu...<正>According to the piezoelectric equation and the vibration theory of the quartz crystal,the relations between the vibrating frequency and structural parameters under the thickness-shear-vibration of AT-cut quartz crystal have been studied. The frequency conditions under which quartz crystal resonator formed stationary wave inside the electrode district and the transmission characteristics of wave outside the electrode district have also been discussed.A quartz crystal resonator was developed based on this analysis.The experiment showed that the force-sensing characteristics were independent of the fixation of the crystal edge.The detecting distinguish ability was up to 0.001°,and the short-term frequency stability was up to 1.38×10~ (-10)/min.展开更多
Based on the analysis of one-dimension inertial accelerometer movement model,from which the resolution of the accelerometer inertial mass displacement equation was derived,the response of the sensor sensing element to...Based on the analysis of one-dimension inertial accelerometer movement model,from which the resolution of the accelerometer inertial mass displacement equation was derived,the response of the sensor sensing element to vibration and impact of various frequencies was studied.The theoretical and experimental results show that a reasonable configuration among the sensing element inherent frequency,environmental exciting frequency and the damp factors of the sensor is the key to prevent the sensor from damage.The sensor has good anti-vibrating impact ability when the relative damp factor is 0.7,and the environmental interferential vibrating frequency is less than 0.35 times of the inherent frequency of the sensing element.展开更多
Photocatalytic hydrogen evolution reaction(PC-HER)provides a solution to energy crisis and environmental pollution.Herein,different graphitic carbon nitride(g-C_(3)N_(4))-based van der Waals(vdW)type II homojunctions ...Photocatalytic hydrogen evolution reaction(PC-HER)provides a solution to energy crisis and environmental pollution.Herein,different graphitic carbon nitride(g-C_(3)N_(4))-based van der Waals(vdW)type II homojunctions have been fabricated and g-C_(3)N_(4)/Kdoped g-C_(3)N_(4)nanosheets have an outstanding PC-HER rate of 1,243μmol·h^(−1)·g^(−1)under visible light,higher than that of bulk g-C_(3)N_(4),doped g-C_(3)N_(4)nanosheets,and mixed nanosheets.The enhanced PC-HER performance can be ascribed to the cooperative effects of the shortened bandgap,enlarged specific surface area,matched type II energy band structure,“face to face”vdW charge interaction,and peculiarly partite positions of the conduction and valence bands in different layers.Besides,the type II junctions were found superior to binary type II junction.This study highlights the synergistic effect of different strategies in improving the PC-HER capacities of g-C_(3)N_(4),especially the application of particular vdW junctions,and provides new insights to the structures and mechanism.展开更多
Thanks to its simplicity,versatility,and secondary reactivity,dopamine self-polymerized coatings(pDA)have been widely used in surface modification of biomaterials,but the limitation in secondary molecular grafting and...Thanks to its simplicity,versatility,and secondary reactivity,dopamine self-polymerized coatings(pDA)have been widely used in surface modification of biomaterials,but the limitation in secondary molecular grafting and the high roughness restrain their application in some special scenarios.Therefore,some other catecholamine coatings analog to pDA have attracted more and more attention,including the smoother poly-norepinephrine coating(pNE),and the poly-levodopa coating(pLD)containing additional carboxyl groups.However,the lack of a systematic comparison of the properties,especially the biological properties of the above three catecholamine coatings,makes it difficult to give a guiding opinion on the application scenarios of different coatings.Herein,we systematically studied the physical,chemical,and biological properties of the three catecholamine coatings,and explored the feasibility of their application for the modification of biomaterials,especially cardiovascular materials.Among them,the pDA coating was the roughest,with the largest amount of amino and phenolic hydroxyl groups for molecule grafting,and induced the strongest platelet adhesion and activation.The pLD coating was the thinnest and most hydrophilic but triggered the strongest inflammatory response.The pNE coating was the smoothest,with the best hemocompatibility and histocompatibility,and with the strongest cell selectivity of promoting the proliferation of endothelial cells while inhibiting the proliferation of smooth muscle cells.To sum up,the pNE coating may be a better choice for the surface modification of cardiovascular materials,especially those for vascular stents and grafts,but it is still not widely recognized.展开更多
文摘<正>According to the piezoelectric equation and the vibration theory of the quartz crystal,the relations between the vibrating frequency and structural parameters under the thickness-shear-vibration of AT-cut quartz crystal have been studied. The frequency conditions under which quartz crystal resonator formed stationary wave inside the electrode district and the transmission characteristics of wave outside the electrode district have also been discussed.A quartz crystal resonator was developed based on this analysis.The experiment showed that the force-sensing characteristics were independent of the fixation of the crystal edge.The detecting distinguish ability was up to 0.001°,and the short-term frequency stability was up to 1.38×10~ (-10)/min.
文摘Based on the analysis of one-dimension inertial accelerometer movement model,from which the resolution of the accelerometer inertial mass displacement equation was derived,the response of the sensor sensing element to vibration and impact of various frequencies was studied.The theoretical and experimental results show that a reasonable configuration among the sensing element inherent frequency,environmental exciting frequency and the damp factors of the sensor is the key to prevent the sensor from damage.The sensor has good anti-vibrating impact ability when the relative damp factor is 0.7,and the environmental interferential vibrating frequency is less than 0.35 times of the inherent frequency of the sensing element.
基金supported by the Australian Research Council(No.DP170104264).
文摘Photocatalytic hydrogen evolution reaction(PC-HER)provides a solution to energy crisis and environmental pollution.Herein,different graphitic carbon nitride(g-C_(3)N_(4))-based van der Waals(vdW)type II homojunctions have been fabricated and g-C_(3)N_(4)/Kdoped g-C_(3)N_(4)nanosheets have an outstanding PC-HER rate of 1,243μmol·h^(−1)·g^(−1)under visible light,higher than that of bulk g-C_(3)N_(4),doped g-C_(3)N_(4)nanosheets,and mixed nanosheets.The enhanced PC-HER performance can be ascribed to the cooperative effects of the shortened bandgap,enlarged specific surface area,matched type II energy band structure,“face to face”vdW charge interaction,and peculiarly partite positions of the conduction and valence bands in different layers.Besides,the type II junctions were found superior to binary type II junction.This study highlights the synergistic effect of different strategies in improving the PC-HER capacities of g-C_(3)N_(4),especially the application of particular vdW junctions,and provides new insights to the structures and mechanism.
基金the International Cooperation Project of Science&Technology Department of Sichuan Province,China(2019YFH0103)the National Key Research and Development Program of China(2017YFB0702504)the Applied Basic Research Project of Science&Technology Department of Sichuan Province,China(2017JY0296).
文摘Thanks to its simplicity,versatility,and secondary reactivity,dopamine self-polymerized coatings(pDA)have been widely used in surface modification of biomaterials,but the limitation in secondary molecular grafting and the high roughness restrain their application in some special scenarios.Therefore,some other catecholamine coatings analog to pDA have attracted more and more attention,including the smoother poly-norepinephrine coating(pNE),and the poly-levodopa coating(pLD)containing additional carboxyl groups.However,the lack of a systematic comparison of the properties,especially the biological properties of the above three catecholamine coatings,makes it difficult to give a guiding opinion on the application scenarios of different coatings.Herein,we systematically studied the physical,chemical,and biological properties of the three catecholamine coatings,and explored the feasibility of their application for the modification of biomaterials,especially cardiovascular materials.Among them,the pDA coating was the roughest,with the largest amount of amino and phenolic hydroxyl groups for molecule grafting,and induced the strongest platelet adhesion and activation.The pLD coating was the thinnest and most hydrophilic but triggered the strongest inflammatory response.The pNE coating was the smoothest,with the best hemocompatibility and histocompatibility,and with the strongest cell selectivity of promoting the proliferation of endothelial cells while inhibiting the proliferation of smooth muscle cells.To sum up,the pNE coating may be a better choice for the surface modification of cardiovascular materials,especially those for vascular stents and grafts,but it is still not widely recognized.
