Amorphous carbon films with high sp2 concentrations are deposited by unbalanced magnetron sputtering with a narrow range of substrate bias voltage. Field emission scanning electron microscopes （FESEMs）, high resolut...Amorphous carbon films with high sp2 concentrations are deposited by unbalanced magnetron sputtering with a narrow range of substrate bias voltage. Field emission scanning electron microscopes （FESEMs）, high resolution transmission electron microscopes （HRTEMs）, atomic force microscopes （AFMs）, the Raman spectrometers, nano- indentation, and tribometers are subsequently used to characterize the microstructures and the properties of the resulting films. It is found that the present films are dominated by the sp2 sites. However, the films demonstrate a moderate hardness together with a low internal stress. The high hardness of the deposited film originates from the crosslinking of the sp2 clusters by the sp3 sites. The presence of the graphite-like clusters in the film structure may be responsible for the low internal stress. What is more important is that the resulting films show excellent tribological properties with high load capacity and excellent wear resistance in humid atmospheres. The relationship between the microstructure determined by the deposition condition and the film characteristic is discussed in detail.展开更多
Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and ch...Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.展开更多
Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrog...Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrogenated DLC films were measured on a ball-on-disk tribometer in different testing environments (humid air,dry air, dry O2, dry Ar and dry N2 ) sliding against Si3 N4 balls. The friction surfaces of the films and Si3 N4 balls were observed on a scanning electron microscope (SEM) and investigated by X-ray photoelectron spectroscopy (XPS). The results show that the tribological properties of the hydrogenated DLC films are strongly dependent on the testing environments. In dry Ar and dry N2 environments, the hydrogenated DLC films provide a superlow friction coefficient of about 0. 008 -0.01 and excellent wear resistance (wear life of above 56 km). In dry air and dry O2, the friction coefficient is increased to 0. 025 - 0.04 and the wear life is decreased to about 30 km. When sliding in moist air, the friction coefficient of the films is further increased to 0. 08 and the wear life is decreased to 10. 4 km. SEM and XPS analyses show that the tribological behaviors appear to rely on the transferred carbon-rich layer processes on the Si3 N4 balls and on the friction-induced oxidation of the films controlled by the nature of the testing environments.展开更多
胰腺癌是致命的恶性肿瘤之一,现有的手术切除和化疗手段均未能很好地改善患者的预后情况,因此亟需寻找更安全有效的治疗方法以满足临床治疗需求。抗体偶联药物(antibody drug conjugate,ADC)是一类利用化学连接子将单克隆抗体与小分子...胰腺癌是致命的恶性肿瘤之一,现有的手术切除和化疗手段均未能很好地改善患者的预后情况,因此亟需寻找更安全有效的治疗方法以满足临床治疗需求。抗体偶联药物(antibody drug conjugate,ADC)是一类利用化学连接子将单克隆抗体与小分子细胞毒药物偶联而成的靶向抗肿瘤药物,具有选择性高、效力高、毒副作用低等优势。近年来,ADC在多种肿瘤治疗中的成功应用掀起了抗胰腺癌ADC的研究热潮。本文就ADC的结构和作用机制及其在抗胰腺癌领域中的研究现状作一综述,为今后抗胰腺癌ADC的研究提供一定的参考依据。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.50705093 and 50575217)the Innovative Group Foundation of the National Natural Science Foundation of China(Grant No.50421502)the National Basic ResearchProgram of China(Grant No.2007CB607601)
文摘Amorphous carbon films with high sp2 concentrations are deposited by unbalanced magnetron sputtering with a narrow range of substrate bias voltage. Field emission scanning electron microscopes （FESEMs）, high resolution transmission electron microscopes （HRTEMs）, atomic force microscopes （AFMs）, the Raman spectrometers, nano- indentation, and tribometers are subsequently used to characterize the microstructures and the properties of the resulting films. It is found that the present films are dominated by the sp2 sites. However, the films demonstrate a moderate hardness together with a low internal stress. The high hardness of the deposited film originates from the crosslinking of the sp2 clusters by the sp3 sites. The presence of the graphite-like clusters in the film structure may be responsible for the low internal stress. What is more important is that the resulting films show excellent tribological properties with high load capacity and excellent wear resistance in humid atmospheres. The relationship between the microstructure determined by the deposition condition and the film characteristic is discussed in detail.
基金Projects(59925513 50323007) supported by the National Natural Science Foundation of China+2 种基金 project(G1999065005) supported by the National Basic Research Program of China project(2003AA305670) supported by the Hi-tech Research and Development Program of China and supported by "Top Hundred Talents Program" of Chinese Academy of Sciences
文摘Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.
基金Projects(59925513 50323007) supported by the National Natural Science Foundation of China+1 种基金 Project(2003AA305670) supported by Hi-tech Research and Development Program of China Project supported by the "Top Hundred Talents Program" of Chinese Academy of Sciences
文摘Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrogenated DLC films were measured on a ball-on-disk tribometer in different testing environments (humid air,dry air, dry O2, dry Ar and dry N2 ) sliding against Si3 N4 balls. The friction surfaces of the films and Si3 N4 balls were observed on a scanning electron microscope (SEM) and investigated by X-ray photoelectron spectroscopy (XPS). The results show that the tribological properties of the hydrogenated DLC films are strongly dependent on the testing environments. In dry Ar and dry N2 environments, the hydrogenated DLC films provide a superlow friction coefficient of about 0. 008 -0.01 and excellent wear resistance (wear life of above 56 km). In dry air and dry O2, the friction coefficient is increased to 0. 025 - 0.04 and the wear life is decreased to about 30 km. When sliding in moist air, the friction coefficient of the films is further increased to 0. 08 and the wear life is decreased to 10. 4 km. SEM and XPS analyses show that the tribological behaviors appear to rely on the transferred carbon-rich layer processes on the Si3 N4 balls and on the friction-induced oxidation of the films controlled by the nature of the testing environments.
文摘胰腺癌是致命的恶性肿瘤之一,现有的手术切除和化疗手段均未能很好地改善患者的预后情况,因此亟需寻找更安全有效的治疗方法以满足临床治疗需求。抗体偶联药物(antibody drug conjugate,ADC)是一类利用化学连接子将单克隆抗体与小分子细胞毒药物偶联而成的靶向抗肿瘤药物,具有选择性高、效力高、毒副作用低等优势。近年来,ADC在多种肿瘤治疗中的成功应用掀起了抗胰腺癌ADC的研究热潮。本文就ADC的结构和作用机制及其在抗胰腺癌领域中的研究现状作一综述,为今后抗胰腺癌ADC的研究提供一定的参考依据。
