检索结果-南通市图书馆

Polyaniline Formed in Alkaline Solution─A New Luminous material

在线全文

学校读者我要写书评

暂无评论

Chinese chemical Letters 2000年第8期11卷 681-684页

作者： Nian Bing LI (college of Chemistry and chemical engineering, Southwest china Normal university, Chongqing 400715) Sheng Tao ZHANG, Pei Dao DING (college of Chemistry and chemical engineering, Chongqing university, Chongqing 400044) SW china Normal Univ Coll Chem & Chem Engn Chongqing 400715 Peoples R China Chongqing Univ Coll Chem & Chem Engn Chongqing 400044 Peoples R China

Electropolymerization of aniline in KOH solution and properties of the polymer are studied by using in situ reflex ellipsometry, cyclic voltammetry and fluorescence spectroscopic method. The change patterns of ellipsometric parameters and the thickness of film in the process of electropolymerization are investigated. The complex refractive indices and the fluorescence spectra of PAN indicate that the PAN is a new kind of luminous material.

关键词： Polyaniline electropolymerization alkaline solution luminous material.

Solution space analysis of Double Lunar-Swingby periodic trajectory

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第8期53卷 2081-2088页

作者： LUO ZongFu ,MENG YunHe&TANG GuoJian college of Aerospace and material engineering,National university of Defense Technology,Changsha 410073,china 1. college of Aerospace and material engineering National University of Defense Technology Changsha 410073 China

The Double Lunar-Swingby(DLS)periodic trajectory is a type of large-scale trajectory in Restricted Three-Body Problem ***,the principium of the DLS periodic trajectory is studied,and a preliminary design of the DLS trajectory is developed by the Patched Conic ***,the solution space of the DLS periodic trajectory is discussed in detail and in combination with numerical simulation,a distribution about orbital parameter relationship in the solution space is ***,the variations of the orbital elements with different rotation angular velocities of geocentric apsidal line are found,and two typical orbits are given according to three reference *** is shown that Patched Conic method is feasible for the DLS periodic trajectory solution space analysis,and the conclusions will be valuable to the deep-space exploration orbit design in future.

关键词： Double Lunar-Swingby patched conics solution space analysis orbit design periodic orbit

Combustion Synthesis and Luminescent Properties of CaO: Eu^(3+), M^+ (M=Li, Na, K) Phosphor

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(materials science) 2010年第2期25卷 179-183页

作者：康明 college of material science and engineering Southwest University of Science and Technology

Li ^＋ , Na^ ＋ , or K ^＋ co-doped CaO： Eu^3＋ phosphors were prepared by the combustion synthesis method and characterized by X-ray diffraction （XRD）, photoluminescence and photolumi-nescence excitation （PL-PLE） spectra. The experimental results show that, upon excitation with 250 nm xenon light, the emission spectrum of the CaO： Eu^3＋ consists of 4f-4f emission transitions from the 5D0 excited level to the 7FJ （J=1, 2, 3） levels with the mainly electric dipole transition 5D0→7F2 of Eu3＋, indicating that the Eu^3＋ occupies a low symmetry. The charge-transfer band （CTB） shows somewhat red shift with the decreasing ionic radii of co-doped alkali metal ions. The PL and PLE intensities are significantly enhanced, especially the strongest intensity of luminescent is CaO： Eu^3＋, Li ＋ phosphor, when alkali metal ions are incorporated. The strongest peak of emission is slightly shifted from 614 to 593 nm, indicating that the Eu^3＋ ion locates in a symmetric position （Oh） when alkali metal ions are incorporated.

关键词： luminescence CaO: Eu^3+ combustion method

Synthesis of a novel benzoxazine containing benzoxazole structure

在线全文

学校读者我要写书评

暂无评论

Chinese chemical Letters 2010年第5期21卷 558-562页

作者： Po Yang,Yi Gu State Key Laboratory of Polymer materials engineering,college of Polymer science and engineering, Sichuan university,Chengdu 610065,china [a] State Key Laboratory of Polymer materials engineering College of Polymer Science engineering Sichuan University Chengdu 610065 China

A high-purity benzoxazine（Boz-BOA） containing benzoxazole structure was successfully synthesized by three-step synthetic method using 2-（4-aminophenyl）-1H-benzoxazole-5-amine（BOA） and *** structure of Boz-BOA was confirmed by FTIR and;H NMR *** DSC was utilized to probe the curing behavior of Boz-BOA and exhibited a narrow melting peak and curing exothermic peak.

关键词： Benzoxazine Benzoxazole Synthesis Characterization

Sol-gel preparation and characterization of Li_(1.3)Al_(0.3)Ti_(1.7)(PO_4)_3 sintered with flux of LiBO_2

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第5期29卷 515-518页

作者： WU Xianming,LI Runxiu,CHEN Shang,HE Zeqiang,and MA Mingyou college of Chemistry and chemical engineering,Jishou university,Jishou 416000,china college of Chemistry and chemical engineering Jishou University Jishou China

Li1.3Al0.3Ti1.7（PO4）3 pellets sintered with different mole fractions of LiBO2 were prepared by sol-gel method. The structural identification, surface morphology, ionic conductivity, and activation energy of the pellets were studied by X-ray diffraction, scanning electron microscopy, and electrochemical impedance spectroscopy. The results show that all the Li1.3Al0.3Ti1.7（PO4）3 pellets sintered with different mole fractions of LiBO2 have similar X-ray diffraction patterns. The sintered pellet becomes denser and the boundary and comer of the particles become illegible with the increase of LiBO2. Among the Lil.3Al0.3Ti1.7（PO3）4 pellets sintered with different mole fractions of LiBO2, the one sintered with 1 mol% LiBO2 shows the highest ionic conductivity of 3.95×10^-4 ***^-1 and the lowest activation energy of 0.2469 eV.

关键词： phosphates sol-gel process sintering ionic conductivity electrochemical impedance spectroscopy

Mining and Integrating Reliable Decision Rules for Imbalanced Cancer Gene Expression Data Sets

在线全文

学校读者我要写书评

暂无评论

Tsinghua science and Technology 2012年第6期17卷 666-673页

作者： Hualong Yu 1 , Jun Ni 2 , Yuanyuan Dan 3 , Sen Xu 4 1. School of Computer science and engineering, Jiangsu university of science and Technology, Zhenjiang 212003, china 2. Department of Radiology, Carver college of Medicine, The university of Iowa, Iowa City, IA 52242, USA 3. School of Biology and chemical engineering, Jiangsu university of science and Technology, Zhenjiang 212003, china 4. School of Information engineering, Yancheng Institute of Technology, Yancheng 224051, china School of Computer science and engineering Jiangsu University of Science and Technology Zhenjiang 212003 China|c|

There have been many skewed cancer gene expression datasets in the post-genomic era. Extraction of differential expression genes or construction of decision rules using these skewed datasets by traditional algorithms will seriously underestimate the performance of the minority class, leading to inaccurate diagnosis in clinical trails. This paper presents a skewed gene selection algorithm that introduces a weighted metric into the gene selection procedure. The extracted genes are paired as decision rules to distinguish both classes, with these decision rules then integrated into an ensemble learning framework by majority voting to recognize test examples; thus avoiding tedious data normalization and classifier construction. The mining and integrating of a few reliable decision rules gave higher or at least comparable classification performance than many traditional class imbalance learning algorithms on four benchmark imbalanced cancer gene expression datasets.

关键词： cancer gene expression data class imbalance paired differential expression genes decision ruleensemble learning majority voting

Comparison of Structure and Properties among Various PAN Fibers for Carbon Fibers

在线全文

学校读者我要写书评

暂无评论

Journal of materials science & Technology 2005年第3期21卷 376-380页

作者： Dongxin HE, Chengguo WANG, Yujun BAI and Bo ZHU college of materials science and engineering, Shandong university, Jinan 250061, china college of materials science and engineering Shandong University Jinan 250061 China

To find out the high-quality polyacrylonitrile (PAN) fibers, some differences are sought by comparing domestic PAN fibers with the foreign ones. X-ray diffractometer (XRD), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectrometer, elemental analyzer, tensile-testing machine and high-temperature differential scanning calorimeter (DSC) are used to characterize the individual microstructure, chemical structure, elemental content, mechanical properties and thermal properties. It is found that high-quality PAN fibers have high density, lower titre, higher or adequate tensile strength, and they also have better conglomeration structure, smaller crystal dimension with dispersive distribution, less microvoids and flaws.

关键词： Polyacrylonitrile (PAN) fiber Carbon fiber Structure Properties

Electrochemical behaviour of commercially pure titanium and Co-Cr alloy in Ringer's solution

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2002年第4期21卷 266-270页

作者： LIANG Chenghao and MOU ThanqiSchool of chemical engineering, Dalian university of Technology, Dalian 116012, china School of chemical engineering Dalian University of Technology Dalian 116012

The electrochemical behaviors of commercially pure titanium (CP Ti) and Co-Cralloy in Ringer's solution have been investigated. The results indicate that the electric potentialof passive region for CP Ti is up to 3000 mV, and its passive current density is 3.078 μA/cm^*** excellent corrosion resistance of CP Ti can be attributed to the formation of TiO_2 oxide *** passive region of Co-Cr alloy is 770 mV, which is narrower than that of CP Ti. However, nohysteresis loops are found in the reverse scanning curves of Cu-Cr alloy. A complex oxide film ofCo_3O_4, Co_2O_3, and Cr_2O_3 formed on the surface provides Co-Cr alloy with a stableelectrochemistry property. The corrosion rates of the crevice samples increase with the pH value ofmedium decreasing. The electron probe microanalyzer (EPMA) analysis indicates that Ti in CP Ti andCo, Cr in Co-Cr alloy dissolve in crevice area due to the Sealed-Cell effect.

关键词： ringer's solution biomedical material electrochemical behaviors

Kinetics and Mechanism of the Polymerization of Methyl Methacrylate in a Y(acac)_3/n-BuMgCl System

在线全文

学校读者我要写书评

暂无评论

chemical Research in Chinese Universities 2000年第1期16卷 61-66页

作者： PAN Zhi-da SUN Jun-quan and YANG Shi-lin (college of chemical engineering, Zhejiang university, Hangzhou 310027, china) Zhejiang Univ Coll Chem Engn Hangzhou 310027 Peoples R China

Based on the kinetics equation proposed by T. Kagiya, the kinetic study on the polymerization of methyl methacrylate(MMA) by Y(acac)_3/n-BuMgCl was carried out with a dilatometer. It was found that the rate of propagation is the first order with respect to the concentration of both active center and monomer. Thus, the equation of propagation rate can be described as R_p=K_p[c][M]. In addition, the instantaneous chain initiation and single molecular termination were concluded for the present system. The activation energy is close to 32 kJ/mol. In the polymerization, n-BuMgCl acts not only as the cocatalyst, but also as chain transfer agent with c_I=3. 6 × 10^(-4).

关键词： Polymerization Kinetics Mechanism Methyl methacrylate Rare earth catalyst