http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Zequn Zhang (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Arrays of horizontal carbon nanotubes of controlled chirality grown using designed catalysts
Zhang, Shuchen,Kang, Lixing,Wang, Xiao,Tong, Lianming,Yang, Liangwei,Wang, Zequn,Qi, Kuo,Deng, Shibin,Li, Qingwen,Bai, Xuedong,Ding, Feng,Zhang, Jin Macmillan Publishers Limited, part of Springer Nat 2017 Nature Vol.543 No.7644
<P>The semiconductor industry is increasingly of the view that Moore's law-which predicts the biennial doubling of the number of transistors per microprocessor chip-is nearing its end(1). Consequently, the pursuit of alternative semiconducting materials for nanoelectronic devices, including single-walled carbon nanotubes (SWNTs), continues(2-4). Arrays of horizontal nanotubes are particularly appealing for technological applications because they optimize current output. However, the direct growth of horizontal SWNT arrays with controlled chirality, that would enable the arrays to be adapted for a wider range of applications and ensure the uniformity of the fabricated devices, has not yet been achieved. Here we show that horizontal SWNT arrays with predicted chirality can be grown from the surfaces of solid carbide catalysts by controlling the symmetries of the active catalyst surface. We obtained horizontally aligned metallic SWNT arrays with an average density of more than 20 tubes per micrometre in which 90 per cent of the tubes had chiral indices of (12, 6), and semiconducting SWNT arrays with an average density of more than 10 tubes per micrometre in which 80 per cent of the nanotubes had chiral indices of (8, 4). The nanotubes were grown using uniform size Mo2C and WC solid catalysts. Thermodynamically, the SWNT was selectively nucleated by matching its structural symmetry and diameter with those of the catalyst. We grew nanotubes with chiral indices of (2m, m) (where m is a positive integer), the yield of which could be increased by raising the concentration of carbon to maximize the kinetic growth rate in the chemical vapour deposition process. Compared to previously reported methods, such as cloning(5,6), seeding(7,8) and specific-structure-matching growth(9-11), our strategy of controlling the thermodynamics and kinetics offers more degrees of freedom, enabling the chirality of as-grown SWNTs in an array to be tuned, and can also be used to predict the growth conditions required to achieve the desired chiralities.</P>
-
Zequn Zhang,Qijuan Dong,Zhibin Chen,Junsheng Wu,Jiuyang Xia,Kang Huang,Pengcheng Zuo,Wei Xue,Bowei Zhang 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.2
The influence of Co content on the microstructure and corrosion behavior of Al0.3CoxCrFeNi (x = 0.25, 0.5 and 1.0) highentropy alloys were investigated. The results indicated that the increased content of Co improve the corrosion resistanceof alloy, which can be attributed to the distinction of phase composition in alloys caused by different Co content. TheAl0.3CoxCrFeNi alloy shows a double-phase (FCC + BCC) structure for x = 0.25 and 0.5, and BCC phase consists of (Al,Ni)-rich B2 phase and (Cr, Fe, Co)-rich A2 phase. The increase of Co content induces the transformations of crystalstructuresfrom BCC to FCC, resulting in the decrease of BCC phase proportion. The Al0.3CoCrFeNi alloy exhibits thesingle FCC structure, and all elements tend to be homogeneously distributed. The difference in the potential of FCC andBCC phases indicates the BCC phase acts as anode resulting to localized corrosion, while B2 phase preferentially dissolvescompared to the A2 phase due to the lower potential. Therefore, the existence of selective corrosion is found in thealloys with double-phase, by contrast, the alloy with single FCC phase shows random pitting corrosion.
-
Min Zhang,Zequn Zhang,Qun Wu,Fuzhi Ke,Jianguo Xu,Siqing Zhao,Gang Wang,Chi Zhang 한국원예학회 2020 원예과학기술지 Vol.38 No.1
Chimeras occur spontaneously or artificially and are valuable in horticultural crop breeding. A new diploid citrus chimera, named ‘Hongrou Huyou’ (abbreviated HH) (Citrus changshan-huyou + C. unshiu), was found during a bud sports investigation in China. The morphology, flesh carotenoid content, and molecular markers were evaluated in HH and the two grafted donors. The results showed that characteristics derived from L2/L3, such as the fruit size, winged leaf, seed, pollen, and rind aroma, were similar to those of C. changshan-huyou (CH), whereas the juice sac and stomatal characteristics originating from L1 were the same as those of the satsuma mandarin. High-performance liquid chromatography analysis of carotenes from the flesh of HH showed that the content was the same as that of the satsuma mandarin, with β-cryptoxanthin producing the main carotenoid spectrum, whereas lutein and violaxanthin were the main carotenoids in CH. Nuclear simple sequence repeat, chloroplast simple sequence repeat, and mitochondrial simple sequence repeat analyses showed that the leaves, outer pericarp (epidermis and flavedo), segment wall, and juice sac of HH contained the nuclear, chloroplast, and mitochondrial genomes of both donors; however, the albedo of HH only contained the genetic material of CH. Thus, HH is confirmed to be a periclinal chimera that consists of L1 from C. unshiu and L2/L3 from CH.
-
Recent developments and challenges in welding of magnesium to titanium alloys
Auwal, S.T.,Ramesh, S.,Tan, Caiwang,Zhang, Zequn,Zhao, Xiaoye,Manladan, S.M. Techno-Press 2019 Advances in materials research Vol.8 No.1
Joining of Mg/Ti hybrid structures by welding for automotive and aerospace applications has attracted great attention in recent years due mainly to its potential benefit of energy saving and emission reduction. However, joining them has been hampered with many difficulties due to their physical and metallurgical incompatibilities. Different joining processes have been employed to join Mg/Ti, and in most cases in order to get a metallurgical bonding between them was the use of an intermediate element at the interface or mutual diffusion of alloying elements from the base materials. The formation of a reaction product (in the form of solid solution or intermetallic compound) along the interface between the Mg and Ti is responsible for formation of a metallurgical bond. However, the interfacial bonding achieved and the joints performance depend significantly on the newly formed reaction product(s). Thus, a thorough understanding of the interaction between the selected intermediate elements with the base metals along with the influence of the associated welding parameters are essential. This review is timely as it presents on the current paradigm and progress in welding and joining of Mg/Ti alloys. The factors governing the welding of several important techniques are deliberated along with their joining mechanisms. Some opportunities to improve the welding of Mg/Ti for different welding techniques are also identified.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
