China Jiliang University

About: China Jiliang University is a education organization based out in Hangzhou, China. It is known for research contribution in the topics: Fiber optic sensor & Optical fiber. The organization has 9291 authors who have published 8932 publications receiving 95279 citations. The organization is also known as: China Institute of Metrology.

Isolation of a Small Carbon Nanotube: The Surprising Appearance of D5h(1)‐C90

Abstract: Since the macroscopic synthesis of C60 and C70 in 1990, [1] the fullerene family has drawn attention with potential applications in a wide range of scientific and industrial areas. C60, C70, C76, C78, and C84 have become well-known; however, the carbon soot from arc generators contains small amounts (generally less than 1%) of higher fullerenes. The isolation of these higher fullerenes in isomerically pure form is challenging, especially since the number of isomers that follow the isolated-pentagon rule (IPR) increases as the size of the fullerene cage expands. The isolated-pentagon rule requires that each pentagon be surrounded by five hexagons to avoid strain-inducing pentagon–pentagon contact. There are 46 isomers of C90 that obey the IPR, but none of these has been obtained in pure form. In regard to unfunctionalized C90, Achiba et al. utilized C NMR spectroscopy to determine that an enriched sample of C90 contained five isomers: one with C2v symmetry, three with C2 symmetry, and one with C1 symmetry. [3] Shi and co-workers reported the separation andUV/Vis spectra of two isomers of C90 from arcgenerated carbon soot obtained from ytterbium-doped graphite rods. Several computational studies have been performed to better understand which specific isomers are expected to be stable. Slanina et al. concluded from semiempirical quantum-chemical calculations that the C2(45), C2v(46), Cs(35), C2(18), and C1(9) isomers are likely to be the most stable at the temperatures used for C90 production. [6] Computations at the B3LYP/6-31G level by Sun indicated that the C2(45) isomer was the most stable, and C2(28), C1(30), C1(32), Cs(35), C2(40), and C2v(46) were other stable isomers. [7] Watanabe et al. performed PM3 computations and concluded that there are 11 isomers (D5h(1), C1(27), C2(28), C1(29), C1(30), C1(31), C1(32), Cs(34), Cs(35),C2(45), andC2v(46)) that are kinetically as well as thermodynamically stable. Some adducts of C90 have also been structurally identified. Recently, a trifluoromethyl adduct of C90, C90(CF3)12, which was synthesized by the free-radical addition of CF3I to a mixture of higher fullerenes, was shown through F NMR spectroscopy to utilize the C1(32)-C90 cage. [9] The chlorination of a mixture of higher fullerenes through treatment with SbCl5 yielded a crystalline material containing C90Cl32. [10] Crystallographic analysis revealed that a single crystal contained a mixture of two isomers that utilized the C2v(46)-C90 and Cs(34)-C90 cages. Carbon soot was obtained by vaporizing a graphite rod filled with Sm2O3 and graphite powder in an electric arc as outlined previously. The carbon soot was extracted with o-dichlorobenzene, and the soluble extract was subjected to a multistage high pressure liquid chromatographic (HPLC) isolation process involving three complementary chromatographic columns (Buckyprep-M, Buckyprep, and 5PBB) with either chlorobenzene or toluene as the eluent. Three individual isomers of C90 were identified and purified. These isomers are labeled C90(I), C90(II), and C90(III) in the order of their chromatographic elution times. Figure 1 shows the HPLC chromatogram and laser desorption ionization time-of-flight (LDI-TOF) mass spectrum of the purified sample of the firsteluted isomer, C90(I). We obtained isomer-free C90(II) and C90(III) in a similar fashion (see the Supporting Information). C90(I) differs distinctly from C90(II) and C90(III) in terms of its retention time (Table 1). The unusually short retention time observed for C90(I) on the polar stationary phases of both the phenothiazine-derivatized Buckyprep-M and pentabromobenzyl (5PBB) columns suggested that it is less polar than C90(II) or C90(III), whereas the relatively long retention time on the nonpolar pyrenylethyl silica of the Buckyprep column suggested that C90(I) has a more elongated structure that enables better p–p interaction with the stationary phase. The three isomers of C90 display quite different UV/Vis/ near-infrared (NIR) absorption behavior (Figure 2). C90(I) produces two characteristic absorptions at 484 and 589 nm, whereas C90(II) exhibits a strong band with strong but poorly resolved peaks around 413 and 453 nm, and C90(III) shows an almost featureless spectrum with broad bands at 602 and [*] H. Yang, Z.-M. Wang, A. Jiang, Prof. Dr. Z.-Y. Liu Department of Chemistry, Zhejiang University Hangzhou 310027 (China) Fax: (+86)571-8795-1895 E-mail: zyliu@zju.edu.cn

Text categorization based on regularization extreme learning machine

Abstract: This article proposes a novel approach for text categorization based on a regularization extreme learning machine (RELM) in which its weights can be obtained analytically, and a bias-variance trade-off could be achieved by adding a regularization term into the linear system of single-hidden layer feedforward neural networks. To fit the input scale of RELM, the latent semantic analysis was used to represent text for dimensionality reduction. Moreover, a classification algorithm based on RELM was developed including the uni-label (i.e., a document can only be assigned to a unique category) and multi-label (i.e., a document can be assigned to multiple categories simultaneously) situations. The experimental results in two benchmarks show that the proposed method can produce good performance in most cases, and it could learn faster than popular methods such as feedforward neural networks or support vector machine.

Photonic Crystal Fiber Strain Sensor Based on Modified Mach–Zehnder Interferometer

Abstract: In this paper, a novel strain sensor is proposed and demonstrated by employing a modified photonic crystal fiber (PCF)-based Mach-Zehnder interferometer, in which a collapsed region is introduced at the middle point of the PCF to improve the extinction ratio. Experimental results show that this proposed structure has a high sensitivity of 11.22 over a range of 1.28 and high-temperature stability.

Research Progress on the Collaborative Drag Reduction Effect of Polymers and Surfactants.

Abstract: Polymer additives and surfactants as drag reduction agents have been widely used in the field of fluid drag reduction. Polymer additives can reduce drag effectively with only a small amount, but they degrade easily. Surfactants have an anti-degradation ability. This paper categorizes the mechanism of drag reducing agents and the influencing factors of drag reduction characteristics. The factors affecting the degradation of polymer additives and the anti-degradation properties of surfactants are discussed. A mixture of polymer additive and surfactant has the characteristics of high shear resistance, a lower critical micelle concentration (CMC), and a good drag reduction effect at higher Reynolds numbers. Therefore, this paper focuses more on a drag reducing agent mixed with a polymer and a surfactant, including the mechanism model, drag reduction characteristics, and anti-degradation ability.