Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional ...Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional argon(Ar).The N-NDFs were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.The grain sizes are of 8~10 nm in dimension.The N-NDF shows n-type behavior and the corresponding N-NDF/p-Si heterojunction diodes are realized with a high rectification ratio of 102 at^7.8 V,and the current density reaches to1.35 A/cm2 at forward voltage of 8.5 V.The findings suggest that fabricated by CH_4/H_2/N_2 without Ar,the N-NDFs and the related rectifying diodes are favorable for achieving high performance diamond-based optoelectronic devices.展开更多
This work focused on the effect of nanocrystalline cellulose （NCC） on the curing characteristics, aging resistance and thermal stability of natural rubber （NR） reinforced with carbon black （CB）. Sharing the same...This work focused on the effect of nanocrystalline cellulose （NCC） on the curing characteristics, aging resistance and thermal stability of natural rubber （NR） reinforced with carbon black （CB）. Sharing the same fillers loading of 45 parts per hundred rubber （phr）, NR/NCC/CB composites with different NCC/CB ratios （i.e. 0/45, 5/40, 10/35, 15/30, 20/25 phr） were prepared and analyzed. Resorcinol and hexamethylene tetramine （RH）, acting as the modifier in NR/NCC interface, was also discussed for its influence. The result showed that an relatively higher ratio of NCC/CB led to a lower torque, a shorter cure time （Tg0）, a slightly longer scorch time （Ti0） and a bigger vulcanization rate constant （K）. This tendency suggested that the existence of NCC accelerated the vulcanization process. Additionally, modified by RH, NR/NCC/CB compounds exhibited a short T10 and a elevated torque. And a moderate RH content would lower the E of vulcanization. A 10 phr substitute of CB by NCC can help to improve aging resistance in terms of mechanical properties. In a high temperature aging condition, composites with 10 phr NCC also performed the highest storage modulus （G＇） among composites tested. A moderate NCC content contributed to the best retention of G＇ after high temperature aging, so did the incorporation of RH. With the partial replacement of CB by NCC, the temperature of 5% weight-lose had a slight drop and the apparent crosslink density showed a decrease. Thanks to the interaction of RH with both NR and NCC, composites showed an improvement in apparent crosslink density after modified by RH.展开更多
In this paper, we comprehensively investigate the influences of M（M=Cu, Co, Mn） substitution for Ni on the structures and electrochemical hydrogen storage characteristics of the nanocrystalline and amorphous Mg20Ni1...In this paper, we comprehensively investigate the influences of M（M=Cu, Co, Mn） substitution for Ni on the structures and electrochemical hydrogen storage characteristics of the nanocrystalline and amorphous Mg20Ni10-xMx（M=Cu, Co, Mn; x = 0–4） alloys prepared by melt spinning. The as-spun（M=None, Cu） alloys display an entire nanocrystalline structure, whereas the as-spun（M=Co, Mn） alloys hold a mixed structure of both nanocrystalline and amorphous when x = 4（M content）. These results indicate that the substitution of M（M=Co, Mn） for Ni facilitates the glass formation in Mg2Ni-type alloy. All the as-spun alloys have the Mg2 Ni major phase, but M（M=Co, Mn） substitution brings on some secondary phases,such as Mg Co2, Mg phases for M=Co, and Mn Ni, Mg phases for M=Mn. The substitution of M（M=Cu, Co, Mn）for Ni also makes a positive contribution to the cycle stability of the alloys in the following orders：（M=Cu） [（M=Co） [（M=Mn） for x = 1 and（M=Co） [（M=Mn）[（M=Cu） for x = 2–4. Meanwhile, it notably enhances the discharge capacity of the alloys in the sequence of（M=Co） [（M=Mn） [（M=Cu）. As for the high rate discharge ability, it visibly upgrades with the growing of M content for（M=Cu, Co）, while it grows at first and then declines for（M=Mn）.展开更多
Magnetically soft Fe-Co-based nanocrystalline alloy films were produced by two preparation methods:One using a new energetic cluster deposition technique and another using a conventional magnetron sputtering technique...Magnetically soft Fe-Co-based nanocrystalline alloy films were produced by two preparation methods:One using a new energetic cluster deposition technique and another using a conventional magnetron sputtering technique.Their structural,static magnetic properties and high-frequency magnetic characteristics were investigated.In the energetic cluster deposition method,by applying a high-bias voltage to a substrate,positively charged clusters in a cluster beam were accelerated electrically and deposited onto a negatively biased substrate together with neutral clusters from the same cluster source,to form a high-density Fe-Co alloy cluster-assembled film with good high-frequency magnetic characteristics.In the conventional magnetron sputtering method,only by rotating substrate holder and without applying a static inducing magnetic field on the substrates,we produced Fe-Co-based nanocrystalline alloy films with a remarkable in-plane uniaxial magnetic anisotropy and a good soft magnetic property.The obtained Fe-Co-O,Fe-Co-Ti-N,and Fe-Co-Cr-N films all revealed a high real permeability exceeding 500 at a frequency up to 1.2 GHz.This makes Fe-Co-based nanocrystalline alloy films potential candidates as soft magnetic thin film materials for the high-frequency applications.展开更多
基金financially supported by the Programs for New Century Excellent Talents in University(NCETNo.06-0303)the National Natural Science Foundation of China(NSFC,No.50772041)
文摘Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional argon(Ar).The N-NDFs were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.The grain sizes are of 8~10 nm in dimension.The N-NDF shows n-type behavior and the corresponding N-NDF/p-Si heterojunction diodes are realized with a high rectification ratio of 102 at^7.8 V,and the current density reaches to1.35 A/cm2 at forward voltage of 8.5 V.The findings suggest that fabricated by CH_4/H_2/N_2 without Ar,the N-NDFs and the related rectifying diodes are favorable for achieving high performance diamond-based optoelectronic devices.
基金supported by the National Natural Science Foundation of China(No.51173046)National Natural Science Foundation of China Joint Fund of Guangdong Province(No.U1134005)
文摘This work focused on the effect of nanocrystalline cellulose （NCC） on the curing characteristics, aging resistance and thermal stability of natural rubber （NR） reinforced with carbon black （CB）. Sharing the same fillers loading of 45 parts per hundred rubber （phr）, NR/NCC/CB composites with different NCC/CB ratios （i.e. 0/45, 5/40, 10/35, 15/30, 20/25 phr） were prepared and analyzed. Resorcinol and hexamethylene tetramine （RH）, acting as the modifier in NR/NCC interface, was also discussed for its influence. The result showed that an relatively higher ratio of NCC/CB led to a lower torque, a shorter cure time （Tg0）, a slightly longer scorch time （Ti0） and a bigger vulcanization rate constant （K）. This tendency suggested that the existence of NCC accelerated the vulcanization process. Additionally, modified by RH, NR/NCC/CB compounds exhibited a short T10 and a elevated torque. And a moderate RH content would lower the E of vulcanization. A 10 phr substitute of CB by NCC can help to improve aging resistance in terms of mechanical properties. In a high temperature aging condition, composites with 10 phr NCC also performed the highest storage modulus （G＇） among composites tested. A moderate NCC content contributed to the best retention of G＇ after high temperature aging, so did the incorporation of RH. With the partial replacement of CB by NCC, the temperature of 5% weight-lose had a slight drop and the apparent crosslink density showed a decrease. Thanks to the interaction of RH with both NR and NCC, composites showed an improvement in apparent crosslink density after modified by RH.
基金financially supported by the National Natural Science Foundations of China (No. 51161015)the Natural Science Foundation of Inner Mongolia, China (Nos. 2011ZD10 and 2010ZD05)
文摘In this paper, we comprehensively investigate the influences of M（M=Cu, Co, Mn） substitution for Ni on the structures and electrochemical hydrogen storage characteristics of the nanocrystalline and amorphous Mg20Ni10-xMx（M=Cu, Co, Mn; x = 0–4） alloys prepared by melt spinning. The as-spun（M=None, Cu） alloys display an entire nanocrystalline structure, whereas the as-spun（M=Co, Mn） alloys hold a mixed structure of both nanocrystalline and amorphous when x = 4（M content）. These results indicate that the substitution of M（M=Co, Mn） for Ni facilitates the glass formation in Mg2Ni-type alloy. All the as-spun alloys have the Mg2 Ni major phase, but M（M=Co, Mn） substitution brings on some secondary phases,such as Mg Co2, Mg phases for M=Co, and Mn Ni, Mg phases for M=Mn. The substitution of M（M=Cu, Co, Mn）for Ni also makes a positive contribution to the cycle stability of the alloys in the following orders：（M=Cu） [（M=Co） [（M=Mn） for x = 1 and（M=Co） [（M=Mn）[（M=Cu） for x = 2–4. Meanwhile, it notably enhances the discharge capacity of the alloys in the sequence of（M=Co） [（M=Mn） [（M=Cu）. As for the high rate discharge ability, it visibly upgrades with the growing of M content for（M=Cu, Co）, while it grows at first and then declines for（M=Mn）.
基金supported by the National Natural Science Foundation of China (Grant Nos.50671087,50971108)the National Outstanding Youth Science Foundation of China (Grant No.50825101)the Intellectual Cluster Project of the Ministry of Education,Culture,Sports,Science,and Technology,Japan,Aichi Prefecture,Nagoya City and Aichi Science and Technology Foundation
文摘Magnetically soft Fe-Co-based nanocrystalline alloy films were produced by two preparation methods:One using a new energetic cluster deposition technique and another using a conventional magnetron sputtering technique.Their structural,static magnetic properties and high-frequency magnetic characteristics were investigated.In the energetic cluster deposition method,by applying a high-bias voltage to a substrate,positively charged clusters in a cluster beam were accelerated electrically and deposited onto a negatively biased substrate together with neutral clusters from the same cluster source,to form a high-density Fe-Co alloy cluster-assembled film with good high-frequency magnetic characteristics.In the conventional magnetron sputtering method,only by rotating substrate holder and without applying a static inducing magnetic field on the substrates,we produced Fe-Co-based nanocrystalline alloy films with a remarkable in-plane uniaxial magnetic anisotropy and a good soft magnetic property.The obtained Fe-Co-O,Fe-Co-Ti-N,and Fe-Co-Cr-N films all revealed a high real permeability exceeding 500 at a frequency up to 1.2 GHz.This makes Fe-Co-based nanocrystalline alloy films potential candidates as soft magnetic thin film materials for the high-frequency applications.
