We describe the results of 532 nm pulse laser-induced breakdown spectroscopy (LIBS) of two samples of magnetite nanoparticles (SPIONs) nanoferrofluid synthesized at room (S1) and elevated temperatures (S2) and at thre...We describe the results of 532 nm pulse laser-induced breakdown spectroscopy (LIBS) of two samples of magnetite nanoparticles (SPIONs) nanoferrofluid synthesized at room (S1) and elevated temperatures (S2) and at three different laser energy levels and pulse frequency. The size of magnetite nanoparticles, size distribution, magnetic crystalline phase and magnetization were analyzed and measured using transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD) and vibrating sample magnetometry (VSM). The SPIONs showed a distribution between 4 - 22 nm with a peak about 12 nm and saturation magnetization of about 65 emu/g. The Saha-Boltzmann analysis of spectra for medium energy level (1050 mJ) yields plasma temperatures of (3881 ± 200) K and (26,047 ± 200) K for Fe I and OV as the lowest and highest temperatures respectively. A range of corresponding electron density (Ne-) of (0.47 - 6.80) × 1020, (0.58 - 8.30) × 1020 and (0.69 - 9.96) × 1020 cm-3?were determined at 860, 1050 and 1260 mJ respectively using the estimated CCD pictures. The results confirmed a higher elements ratio for S1 than S2 and the signal intensity indicated a non-linear behaviour as a function of pulse frequency with the maximum ratio value at 3 Hz. At higher frequency of 6 Hz no such turning point was observed. The highest and lowest temperatures corresponded to Fe I and OV respectively. The LIBS technique can be utilized to study, characterize and determine the elements ratio required in most applications involving the synthesizing process.展开更多
The evolution of discharge dynamics in N_(2)-SF_(6)mixtures under long‐term repetitive submicrosecond pulses is investigated based on pulse‐sequence resolved electrical and optical diagnostics.The effects of gas pre...The evolution of discharge dynamics in N_(2)-SF_(6)mixtures under long‐term repetitive submicrosecond pulses is investigated based on pulse‐sequence resolved electrical and optical diagnostics.The effects of gas pressure,pulse repetition frequency(PRF),and SF6 concentration on discharge evolutions are determined.The number of applied pulses before breakdown is shown to non‐linearly decrease with increasing PRF for all included gas pressures and SF6 concentrations.A higher SF6 concentration is favourable for increasing relative insulation capability under repetitive pulses.Unexpected complexities of discharge evolutions under repetitive pulses are reported for the first time for the discharge mechanism transition when a strong electronegative gas is introduced.A pulse‐to‐pulse progressive streamer(first discharge)‐to‐precursor(before breakdown)transition is observed in an N_(2)-SF_(6)mixture under positive repetitive pulses and is less dependent on gas pressure than traditional scenarios.The formation of a precursor section is jointly supported by electrical and optical signatures.The discharge mechanism transition and the detour phenomenon under repetitive pulses are discussed based on the effects of space charges on the spatial distribution of the electric field strength.展开更多
采用金属硅化物扩散层分隔技术制备了源漏区具有不同硅化物挡板尺寸的环型栅PD SOI MOSFETs,通过CLP实验数据分析器件的硅化物隔离档板的尺寸对SOI NMOSTET抗ESD能力以及对多指栅ggnMOS管子导通均匀性的影响。结果显示,采用了硅化物隔...采用金属硅化物扩散层分隔技术制备了源漏区具有不同硅化物挡板尺寸的环型栅PD SOI MOSFETs,通过CLP实验数据分析器件的硅化物隔离档板的尺寸对SOI NMOSTET抗ESD能力以及对多指栅ggnMOS管子导通均匀性的影响。结果显示,采用了硅化物隔离挡板的管子二次击穿电压明显提高;随着挡板尺寸增加,多指栅的导通均匀性得到明显改善。展开更多
文摘We describe the results of 532 nm pulse laser-induced breakdown spectroscopy (LIBS) of two samples of magnetite nanoparticles (SPIONs) nanoferrofluid synthesized at room (S1) and elevated temperatures (S2) and at three different laser energy levels and pulse frequency. The size of magnetite nanoparticles, size distribution, magnetic crystalline phase and magnetization were analyzed and measured using transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD) and vibrating sample magnetometry (VSM). The SPIONs showed a distribution between 4 - 22 nm with a peak about 12 nm and saturation magnetization of about 65 emu/g. The Saha-Boltzmann analysis of spectra for medium energy level (1050 mJ) yields plasma temperatures of (3881 ± 200) K and (26,047 ± 200) K for Fe I and OV as the lowest and highest temperatures respectively. A range of corresponding electron density (Ne-) of (0.47 - 6.80) × 1020, (0.58 - 8.30) × 1020 and (0.69 - 9.96) × 1020 cm-3?were determined at 860, 1050 and 1260 mJ respectively using the estimated CCD pictures. The results confirmed a higher elements ratio for S1 than S2 and the signal intensity indicated a non-linear behaviour as a function of pulse frequency with the maximum ratio value at 3 Hz. At higher frequency of 6 Hz no such turning point was observed. The highest and lowest temperatures corresponded to Fe I and OV respectively. The LIBS technique can be utilized to study, characterize and determine the elements ratio required in most applications involving the synthesizing process.
基金supported by the National Natural Science Foundation of China(52077168,51777164).
文摘The evolution of discharge dynamics in N_(2)-SF_(6)mixtures under long‐term repetitive submicrosecond pulses is investigated based on pulse‐sequence resolved electrical and optical diagnostics.The effects of gas pressure,pulse repetition frequency(PRF),and SF6 concentration on discharge evolutions are determined.The number of applied pulses before breakdown is shown to non‐linearly decrease with increasing PRF for all included gas pressures and SF6 concentrations.A higher SF6 concentration is favourable for increasing relative insulation capability under repetitive pulses.Unexpected complexities of discharge evolutions under repetitive pulses are reported for the first time for the discharge mechanism transition when a strong electronegative gas is introduced.A pulse‐to‐pulse progressive streamer(first discharge)‐to‐precursor(before breakdown)transition is observed in an N_(2)-SF_(6)mixture under positive repetitive pulses and is less dependent on gas pressure than traditional scenarios.The formation of a precursor section is jointly supported by electrical and optical signatures.The discharge mechanism transition and the detour phenomenon under repetitive pulses are discussed based on the effects of space charges on the spatial distribution of the electric field strength.
基金浙江省新苗人才计划资助(“XinMiao Project of Science and Technology Department of Zhejiang Province”)浙江省自然科学基金资助项目(Zhejiang Province Natural Science Foundation)(Y107055)
文摘采用金属硅化物扩散层分隔技术制备了源漏区具有不同硅化物挡板尺寸的环型栅PD SOI MOSFETs,通过CLP实验数据分析器件的硅化物隔离档板的尺寸对SOI NMOSTET抗ESD能力以及对多指栅ggnMOS管子导通均匀性的影响。结果显示,采用了硅化物隔离挡板的管子二次击穿电压明显提高;随着挡板尺寸增加,多指栅的导通均匀性得到明显改善。
