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51.
In this work, the structure of the ionic liquid [emim]OH and the influence of water molecules on this ionic liquid were studied
by the DFT theory at the B3LYP/6-311++G** level. The calculation results indicate that [emim]OH cannot exist in the form of
ion pairs, rather it is inclined to exist the form of water and imidazole carbene. Further studies showed that water mainly
influences the anion: it can disperse the negative charge of the O atom of the OH− anion and form hydroxyl–water clusters with the anion. When there are two water molecules in the ionic liquid, the system
is most likely to exist in the form of ion-pairs that are composed of hydroxyl–water clusters and cations. Configurations
formed near the C2-H fragment of imidazole were favored, and hydrogen bonding interaction plays an important role in the ionic liquid system. 相似文献
52.
Yong Yan Ke Deng Prof. Zai Yu Zhixiang Wei Prof. 《Angewandte Chemie (International ed. in English)》2009,48(11):2003-2006
A game of Twister : The induced helicity of polyaniline and its supramolecular structures could be tuned by the methyl substitution of one of the monomers. By copolymerization of aniline with m‐toluidine, the helicity of copolymer (PMANI) nanofibers was totally inverted compared to that of polyaniline (PANI), while copolymer nanofibers with o‐toluidine (POANI) had the same helicity as that of polyaniline (see picture).
53.
Zhixiang Wu 《Acta Appl Math》2009,106(2):185-198
In present paper we define a new kind of weak quantized enveloping algebra
of Borcherds superalgebras
. It is a noncommutative and noncocommutative weak graded Hopf algebra. Using localizing with some Ore set, we obtain a different
kind of quantized enveloping algebras of Borcherds superalgebras
. It has a homomorphic image which is isomorphic to the usual quantum enveloping algebra
of
. Moreover,
is isomorphic to a direct sum of
and an other algebra as algebras.
The author is sponsored by ZJNSF No. Y607136. 相似文献
54.
Dequan Li Zhixiang Yin 《Communications in Nonlinear Science & Numerical Simulation》2009,14(3):655-667
The Lü system is a new chaotic system, which connects the Lorenz system and the Chen system and represents the transition from one to the other. In this letter, based on the concept of nonresonant parametric perturbations, further detailed analysis about the forming mechanism and its compound structure for the chaotic Lü system are offered. The obtained results clearly reveal the intermediate chaotic system has another novel forming mechanism: the compression and pull forming mechanism, which provides an enlighten insight about the relationship of its vibration “mode” and the two-scroll “base” chaotic attractor. Then motivated by this novel forming mechanism, by adding a simple nonlinear term to the Lü system, its role as a joint function is revisited. With the gradual tuning the parameter of the nonlinear controller, the transition from the canonical Lorenz attractor to the Chen attractor through the Lü attractor is revived. The scheme herein goes beyond the traditional framework for studying the Lorenz-like systems, which can be very helpful in generating and analyzing of all similar and closely related chaotic systems. 相似文献
55.
采用多波长薄层色谱扫描法,不经过传统的薄层色谱展开步骤实现混合体系的快速定量。废木料液化过程产物为混合体系,分别将不同液化反应时间点所取样品点样于硅胶板上。仅对液化过程终点的样本点进行一次展开,分离斜投影建模所需的反射光谱,切割出目标产物(乙酰丙酸)和背景光谱,构造斜投影算子;对其他液化过程中的样品点不展开,采集混合光谱,经斜投影算法分离出其中的目标产物纯光谱,从而实现定量。将该方法的定量结果与高效液相色谱法的定量结果对比,得到两种方法测定乙酰丙酸的相对误差小于3.27%,表明两种方法具有良好的一致性。 相似文献
56.
How to determine the multipesticide residues in vegetables is an important problem. In this study, a new molecularly imprinted polymer was synthesized using O,O‐dimethyl thiophosphoryl chloride, an intermediate for the manufacture of organophosphorous pesticides, as the template. Characterization test indicated that the synthesized polymer exhibited good recognition and selectivity for dichlorvos, methamidophos, acephate, folimat, monocrotophos, parathion‐methyl, phosphamidon, and malathion. A molecularly imprinted SPE coupled to GC for simultaneous separation and determination of eight organophosphorous pesticides residues was developed. Under optimal conditions, the linear range of this method was 0.001–10.0 mg/L. The LOD of this method was in the range of 0.13–0.90 μg/kg. With a flow rate of 2.5 mL/min for loading 100 mL, the enrichment factor in the range of 25–480 for the eight organophosphorous pesticides was obtained. The RSD of the eight organophosphorous pesticides based on five replicates was from 1.50 to 4.09%. The accuracy of the proposed method was evaluated by recovery measurements on spiked samples, and good recovery rates ranging from 80.11 to 97.70% were achieved. Moreover, this method was evaluated for the quantitative detection of eight organophosphorous pesticide residues in leek and pakchoi samples. 相似文献
57.
Graham Hall Zhixiang Wang 《Journal of Geometry and Physics》2012,62(2):449-463
This paper considers the situation on a 4-dimensional manifold admitting two metric connections, one of which is compatible with a positive definite metric, and which have the same unparametrised geodesics. It shows how, in many cases, the relationship between these connections and metrics can be found. In many of these cases, the connections are found to be necessarily equal. The general technique used is that based on a certain classification of the curvature tensor together with holonomy theory. 相似文献
58.
K. C. Yung Zhixiang Cai H. S. Choy 《Applied Physics A: Materials Science & Processing》2012,107(2):351-355
In this paper, the feasibility of Ti film coated on glass substrate scribed via a 532 nm picosecond laser is investigated.
Laser irradiations from the film side and from the transparent substrate side are performed for comparison. Optical microscopy,
SEM, surface stylus and contact resistance measurement reveal that the Ti film can be completely removed with no damage to
the glass substrate, using optimized process parameters. The complete removal threshold for the film for front-side scribing
is found at 120 mJ/cm2, while the minimum laser fluence for complete scribing is 70 mJ/cm2 in the case of back-side scribing. The lines scribed from the front side exhibit obvious thermal effects such as heat affected
zones, burr and micro cracks. Back-side scribing exhibits non-thermal behavior, which also can increase the process speed
for the scribing of a Ti film on glass to 1000 mm/s. This makes the back-side laser scribing of Ti film a promising technique. 相似文献
59.
Anan Fang Zhixiang Huang Thomas Koschny Costas M. Soukoulis 《Photonics and Nanostructures》2012,10(3):276-280
We present a computational approach, allowing for a self-consistent treatment of three-dimensional (3D) fishnet metamaterial operating at 710 nm wavelength coupled to a gain material incorporated into the nanostructure. We show numerically that loss-free negative index material is achievable by incorporating gain material inside the fishnet structure. The effective gain coefficient of the combined fishnet-gain system is much larger than its bulk counterpart and the figure-of-merit (FOM = | Re(n)/Im(n) |) increases dramatically with gain. Transmission, reflection, and absorption data, as well as the retrieved effective parameters, are presented for the fishnet structure with and without gain. 相似文献
60.
In this study, we apply a self-consistent field theory of polymers to study the structures of a symmetric diblock copolymer in parallel substrates filled with square-pillar arrays in which the substrates and pillars exhibit a weak preference for one block of the copolymer. Three classes of structures, i.e., lamellae, perpendicular cylinders, and bicontinuous structures, are achieved by varying the polymer film thickness, the pillar pitch (the distance between two centers of the nearest neighboring pillars), the gap and rotation of the pillars. Because of the confinement along horizontal directions imposed by the pillar array, eight novel types of perpendicular lamellar structures and eight novel types of cylindrical structures with various shapes and distributions occur. In the hybridization states of the parallel and perpendicular lamellar structures, several novel bicontinuous structures such as the double-cylinder network, pseudo-lamellae, and perforated lamellar structure are also found. By comparing the free energies of the various possible structures, the antisymmetric parallel lamellae are observed to be stable with the larger pillar gap at a certain film thickness. The structural transformations between the alternating cylindrical structures (alternating cross-shaped, square-shaped, and octagonal perpendicular cylinders) and parallel lamellae with increasing film thickness or pillar gap are well explained by the modified strong separation theory. Our results indicate that array confinement can be an effective method to prepare novel polymeric nanopattern structures. 相似文献