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991.
Resorcinarenes的合成及其边缘化学修饰(Ⅱ) 总被引:5,自引:2,他引:3
探讨了烷基醛类(丁醛、戊醛、异丁醛)的Resorcinarenes的合成及其边缘化学修饰(乙酰化、甲基化),研究了烷基取代基对合成的影响,并用IR,^1HNMR,MS和UV对这些化合物进行了表征。 相似文献
992.
An improved spectrophotometry of hydroxamic acids was evaluated. A synthetic aromatic hydroxamic acid for flotation was directly
determined without any extraction in the solution of appropriate acidity. The introduction of ethanol made the process more
stable. The characteristic absorption peak of the soluble complex at the wavelength of 525 nm was sensitive to being detected.
The relationship between the absorbance and the concentration was in accordance with Lambert–Beer’s law in the range 0–120 mg/L,
with a related coefficient of 0.9997. Compared with other determinations, this method considerably reduces the period and
manipulation under the precondition of accuracy, so that it could be an available determination for hydroxamic acids. 相似文献
993.
994.
Shao Su Xinpan Wei Yuanyuan Guo Yiling Zhong Yuanyuan Su Qing Huang Chunhai Fan Yao He 《Particle & Particle Systems Characterization》2013,30(4):326-331
A new kind of silicon nanowire (SiNWs)‐based nanoelectrode assembly, a gold‐nanoparticle‐decorated silicon nanowire array (AuNPs@SiNWsAr), is employed for the construction of high‐performance electrochemical sensors. Significantly, the electrochemical nanosensors are capable of sensitive detection of various electroactive molecules (e.g., dopamine (DA), ascorbic acid (AA), hydrogen peroxide (H2O2), and glucose). Further, DA molecules loaded on the surface of AuNPs@SiNWsAr preserve stable high electroactivity overnight without special protection, while free DA molecules may lose their biological activity due to severe oxidization in ambient environment. These findings may offer new opportunities for the design of high‐performance electrochemical nanosensors with high sensitivity and robust stability. 相似文献
995.
A facile and simple modification method towards changing surface property of ZnO nanorods from a hydrophilic one to a hydrophobic one have been developed by refluxing precursor in three-necked flask. Comparing with the other modifiers discussed in the paper, NDZ-311w titanate coupling agent was selected as the best one not only because of the good lipophilic modification effect, but also for its multifunctional groups could play a crucial part in further composite with organic materials. Moreover, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively, were used to evaluate the morphology, structure and combinative way before and after surface modification. The TEM result showed, after modifying process, there was a thin layer capping on the surface of ZnO nanorods which could be considered as NDZ-311w titanate coupling agent. Through the structure analysis by XRD, it was found that the surface modification had not substantially altered crystalline structure. Besides, the FT-IR test proved that NDZ-311w titanate coupling agent was rather covalently bonded to the surface of ZnO nanorods than physically capping. More practically speaking, the NDZ-311w titanate coupling agent modified ZnO nanorods have much more potential applications in organic materials than unmodified ones. 相似文献
996.
Growth of Intermetallic Compounds in Thermosonic Copper Wire Bonding on Aluminum Metallization 总被引:1,自引:0,他引:1
Hui Xu Changqing Liu Vadim V. Silberschmidt Zhong Chen 《Journal of Electronic Materials》2010,39(1):124-131
Interface evolution caused by thermal aging under different temperatures and durations was investigated by means of scanning
electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that approximately 30-nm-thick and discontinuous
Cu-Al intermetallic compounds (IMCs) were present in the initial bonds before aging. Cu-Al IMCs grew under thermal aging with
increasing aging time. The growth kinetics of the Cu-Al IMCs was correlated to the diffusion process during aging; their combined
activation energy was estimated to be 1.01 eV. Initially, Al-rich Cu-Al IMCs formed in the as-bonded state and early stage
of aging treatment. Cu9Al4 was identified by selected-area electron diffraction (SAD) as the only type of Cu-Al IMC present after thermal aging at 250°C
for 100 h; this is attributed to the relatively short supply of aluminum to the interfacial reaction. 相似文献
997.
998.
999.
Gui‐Zhong Yang Xiao‐Lei Chen Lu‐Min Wang Jian‐Gao Shi Chun‐Zhong Li Tianxi Liu 《先进技术聚合物》2009,20(2):104-110
A series of fluorene‐based rod–coil liquid crystal polymers with different lengths of the coil segments on backbones were designed and synthesized by a palladium‐catalyzed Suzuki coupling‐reaction. The thermal stability, the UV–Vis absorption and fluorescence spectra in chloroform solution and thin film, the electrochemical properties, thermal behavior, and morphology of these rod–coil polymers were investigated. The thermal stability of these polymers steadily decreased on increasing the length of the coil segments on the backbone; their optical and electrochemical properties did not exhibit noticeable dependence on the weight fraction of the coil segments. However, the shoulder emission and the full width at the half‐maximum (FWHM) in PL spectra of the films increased, whereas the oxidation onset potentials and the corresponding HOMO energy levels decreased with the increase in the weight fraction of the coil segments, which was assigned to microphase separation and formation of folded chain conformation as the weight fraction of the coil segments increased. These polymers displayed a characteristic liquid crystalline texture. The variation of the weight fraction of the coil segments obviously affected the thermal behavior and morphology of these rod–coil polymers. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
1000.
With the newly developed octonion analytic function theory, we confirm the octonionic analogue of the Calderón's conjecture. As application, we obtain the Plemelj formula in octonionic space. 相似文献