Sum frequency generation vibrational spectroscopy(SFG-VS)has been demonstrated to be a powerful technique to study the interfacial structures and interactions of biomolecules at the molecular level.Yet most previous s...Sum frequency generation vibrational spectroscopy(SFG-VS)has been demonstrated to be a powerful technique to study the interfacial structures and interactions of biomolecules at the molecular level.Yet most previous studies mainly collected the SFG spectra in the frequency range of 1500–4000 cm-1,which is not always sufficient to describe the detailed interactions at surface and interface.Thorough knowledge of the complex biophysicochemical interactions between biomolecules and surface requires new ideas and advanced experimental methods for collecting SFG vibrational spectra.We introduced some advanced methods recently exploited by our group and others,including(1)detection of vibration modes in the fingerprint region;(2)combination of chiral and achiral polarization measurements;(3)SFG coupled with surface plasmon polaritons(SPPs);(4)imaging and microscopy approaches;and(5)ultrafast time-resolved SFG measurements.The technique that we integrated with these advanced methods may help to give a detailed and high-spatial-resolution 3D picture of interfacial biomolecules.展开更多
The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental obser...The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental observations:(i) The opposite response of the QCM and surface plasmon resonance(SPR) for the activation process;(ii) the marked difference in the responses for IgG/anti-IgG interaction between QCM and SPR.Theoretical analysis and experimental results indicated that QCM is sensitive to the thickness change of the "solidified liquid layer" but not the mass of captured biomolecules(i.e.,the immobilized mass),implying caution must be taken in interpreting QCM results.展开更多
A photonic crystal fiber based surface plasmon resonance(PCF-SPR)sensor is simulated by finite element method and experimentally realized.The calculations show that there is an obvious loss peak in the vicinity of 1.2...A photonic crystal fiber based surface plasmon resonance(PCF-SPR)sensor is simulated by finite element method and experimentally realized.The calculations show that there is an obvious loss peak in the vicinity of 1.2μm while the PCF of LMA-8 is used as a sensor.The suspension of silver nanoparticle mixed with hexadecyl trimethyl ammonium bromide (CTAB)is inhaled into the PCF to form a metal film which can be stimulated to generate plasmon in the experiment.A spectrometer is utilized to detect the continuous broadband transmission spectrum from the PCF.The experimental results verify the loss peak.Compared with the theoretical calculations,the offset of loss peak about 40 nm can be acceptable, because the uniformity of the metal coating is difficult to guarantee and the film thickness is difficult to control.展开更多
Recent studies have indicated that hypervelocity impacts by meteoroids and space debris can induce spacecraft anomalies. However, the basic physical process through which space debris impacts cause anomalies is not en...Recent studies have indicated that hypervelocity impacts by meteoroids and space debris can induce spacecraft anomalies. However, the basic physical process through which space debris impacts cause anomalies is not entirely clear. Currently, impact-generated plasma is thought to be the primary cause of electrical spacecraft anomalies, while the effects of impact-generated mechanical damage have rarely been researched. This paper presents new evidence showing that impact-generated mechanical damage strongly influences electrostatic discharge. Hypervelocity impact experiments were conducted in a plasma drag particle accelerator, using particles with diameters of 200–500 ?m and velocities of 2–7 km/s. The impact-generated mechanical damage on a specimen surface was measured by a stereoscopic microscope and 3D Profilometer and it indicated that microscopic irregularities around the impact crater could be responsible for local electric field enhancement. Furthermore, the influence of impact-generated mechanical damage on electrostatic discharge was simulated in an inverted potential gradient situation. The experimental results show that the electrostatic discharge voltage threshold was significantly reduced after the specimen was impacted by particles.展开更多
基金supported by the National Basic Research Program of China(2010CB923300)the National Natural Science Foundation of China(21273217,91127042,21161160557)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Sum frequency generation vibrational spectroscopy(SFG-VS)has been demonstrated to be a powerful technique to study the interfacial structures and interactions of biomolecules at the molecular level.Yet most previous studies mainly collected the SFG spectra in the frequency range of 1500–4000 cm-1,which is not always sufficient to describe the detailed interactions at surface and interface.Thorough knowledge of the complex biophysicochemical interactions between biomolecules and surface requires new ideas and advanced experimental methods for collecting SFG vibrational spectra.We introduced some advanced methods recently exploited by our group and others,including(1)detection of vibration modes in the fingerprint region;(2)combination of chiral and achiral polarization measurements;(3)SFG coupled with surface plasmon polaritons(SPPs);(4)imaging and microscopy approaches;and(5)ultrafast time-resolved SFG measurements.The technique that we integrated with these advanced methods may help to give a detailed and high-spatial-resolution 3D picture of interfacial biomolecules.
基金supported by the 100 Talents Programme of Chinese Academy of Sciences(08BM031001)the Fok Ying Tung Education Foundation (114013) to H.M.the National Basic Research Program of China (2009CB320300)
文摘The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental observations:(i) The opposite response of the QCM and surface plasmon resonance(SPR) for the activation process;(ii) the marked difference in the responses for IgG/anti-IgG interaction between QCM and SPR.Theoretical analysis and experimental results indicated that QCM is sensitive to the thickness change of the "solidified liquid layer" but not the mass of captured biomolecules(i.e.,the immobilized mass),implying caution must be taken in interpreting QCM results.
基金supported by the Major State Basic Research Development Program of China(No.2010CB327801)the Science and Technology Project of Shandong College(No.J11LG74)the Science and Technology Project of Zaozhuang in Shandong Province(No.201127)
文摘A photonic crystal fiber based surface plasmon resonance(PCF-SPR)sensor is simulated by finite element method and experimentally realized.The calculations show that there is an obvious loss peak in the vicinity of 1.2μm while the PCF of LMA-8 is used as a sensor.The suspension of silver nanoparticle mixed with hexadecyl trimethyl ammonium bromide (CTAB)is inhaled into the PCF to form a metal film which can be stimulated to generate plasmon in the experiment.A spectrometer is utilized to detect the continuous broadband transmission spectrum from the PCF.The experimental results verify the loss peak.Compared with the theoretical calculations,the offset of loss peak about 40 nm can be acceptable, because the uniformity of the metal coating is difficult to guarantee and the film thickness is difficult to control.
文摘Recent studies have indicated that hypervelocity impacts by meteoroids and space debris can induce spacecraft anomalies. However, the basic physical process through which space debris impacts cause anomalies is not entirely clear. Currently, impact-generated plasma is thought to be the primary cause of electrical spacecraft anomalies, while the effects of impact-generated mechanical damage have rarely been researched. This paper presents new evidence showing that impact-generated mechanical damage strongly influences electrostatic discharge. Hypervelocity impact experiments were conducted in a plasma drag particle accelerator, using particles with diameters of 200–500 ?m and velocities of 2–7 km/s. The impact-generated mechanical damage on a specimen surface was measured by a stereoscopic microscope and 3D Profilometer and it indicated that microscopic irregularities around the impact crater could be responsible for local electric field enhancement. Furthermore, the influence of impact-generated mechanical damage on electrostatic discharge was simulated in an inverted potential gradient situation. The experimental results show that the electrostatic discharge voltage threshold was significantly reduced after the specimen was impacted by particles.