Selective recognition in molecularly imprinted polymer and its chromatographic characterization for cinchonine

A molecularly imprinting polymer (MIP) was synthesized via bulk polymerization under different conditions using anti-ague drug cinchonine (CN) as template. Infrared spectra (IR) results show that the template CN and functional monomer α-methyl acrylic acid (MAA) formed complexes before polymerization and the structure of complexes was simulated by Hyperchem. The results indicate that there are hydrogen bond or ionic bond between functional monomer and template molecule in acetonitrile solution. The MIP made in cold-initiated photo-polymerization has higher separation performance than that in the therm-initiated polymerization. The separation of the isomers CN and cinchonidine (CD) can be successfully obtained when its separate factor α reaches 1.82. Scatchard analysis suggests that the MIP recognizing CN with two classes of binding sites. The partition coefficient K _{d, 1} and apparent maximum number n _{max, 1} of binding sites with high affinity are 131.43 μmol/L and 58.90 μmol/g, respectively, while K _{d, 2} and n _{max, 2} of binding sites with low affinity are 2.32 mmol/L and 169.08 mmol/g, respectively. Foundation item: Project(2004035085) supported by the Postdoctoral Science Foundation of China; project(04JJ3080) supported by the Natural Science Foundation of Hunan Province     

Template synthesis and adsorption properties of chitosan salicylal Schiff bases

To improve the adsorption properties of chemically modified chitosan, the chelating resin of salicylal chitosan Schiff bases was prepared by the template cross-linking method using Cu(Ⅱ) as template ion and ethylene glycol bisglycidyl ether as cross-linking agent in microwave, and was characterized by IR. The adsorption capacity and selectivity coefficient of the chemically modified chitosan for Cu(Ⅱ), Fe(Ⅲ) and Zn(Ⅱ) were investigated, respectively. The results show that the adsorption capacity of the resin 2.73 mmol/g for Cu(Ⅱ) is bigger than that for other two metal ions, 0.22 mmol/g for Fe(Ⅲ), and 0.42 mmol/g for Zn(Ⅱ), and the selectivity coefficients are as follows: KCu(Ⅱ)/Fe(Ⅲ)=12.4, KCu(Ⅱ)/Zn(Ⅱ)=6.5.     

Electrochemical behavior of CoCl2 in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

The electrochemical behavior of CoCl2 in 1-butyl-3-methylimidazolium hexafluorophosphate （[bmim]PF6） was investigated by cyclic voltammetry. The cyclic voltammograms were obtained from electrochemical measurement under different temperatures, and the reversible behavior for Co^2＋/Co^3＋ redox couple on glassy carbon electrode in [bmim]PF6 was confirmed by the characteristic of the peak currents. The diffusion coefficients （about 10^-11m^2/s） of Co^2＋ in [bmim]PF6 under different temperatures were evaluated from the dependence of the peak current density on the potential scan rates in cyclic voltammograms. It is found that the diffusion coefficient increases with increasing temperature. Diffusion activation energy of Co^2＋ in [bmim]PF6 is also calculated to be 23.4 kJ/mol according to the relationship between diffusion coefficient and temperature.     

Effects of temperature and initial molar ratio of Na2O to Al2O3 on agglomeration of fine Al（OH）3 seed in synthetic Bayer solution

Fine Al（OH）3 crystals were aggregated from supersaturated aluminate solution in the batch reaction tanks. By means of laser particle size analyzer and scanning electron microscopy, the influences of temperature and initial molar ratio of Na2O to Al2O3 （aK） on agglomeration of fine seed in Bayer process were investigated. The results show that agglomeration is almost finished in 8 h, and seeds with size less than 2 μm are easily aggregated together, and almost disappear in 8 h under the optimal process conditions. In the aluminate solution with the same moderate initial aK, when the reaction temperature reaches 75 ℃, the secondary nucleation does not occur, and the effect of agglomeration is better. And at the same reaction temperature, when the initial aK is 1.62, the initial supersaturation of aluminate solution is moderate, the binders on the surfaces of the seed are enough to maintain the agglomeration process, and the agglomeration degree is better. From SEM images, agglomeration mainly occurs in the fine particles, the combinations among the fine particles are loose and the new formed coarse crystal shapes are irregular.     

Use of double edge-cracked Brazilian disk geometry for compression-shear fracture investigation of rock

A new specimen geometry-the double edge-cracked Brazilian disk and a relevant fracture analysis by weight function method are proposed for the investigation of rock fracture caused by compression-shear loading. Not only can the mixed mode fracture with any ratio of KI /KII be achieved, but also the pure mode n crack extension can be obtained. The combined mode fracture analysis for this geometry shows that diametral compression in the far-field can induce a compression-shear stress state in the singular stress field ahead of crack tips. Experimental investigations conducted on marble specimens show that the pure mode [I crack extension can be obtained when the dimen-sionless crack length a>0. 7 and the inclined crack angle 5°≤ψ≤40°. Normalized mode I and mode II stress intensity factors decrease from -0. 45 and 2. 47 at ψ= 5° to - 1. 65 and 1. 52 at ψ=40°, respectively. The strains at three points of specimen are also measured in order to investigate the influence of stress singularity on initi     

Effects of microstructures on the deformation and fracture behaviors of TiAl-based alloys

The fracture toughnessK _Ic, the tensile deformation and fracture behaviors of different microstructures ofγ-TiAl based alloy, Ti-33Al-3Cr-0.5Mo] were studied at room temperature. It is found that theK _Ic value is lower in the duplex microstructure, and increases with the increase of vol pct of the lamellar microstructure, and that the full lamellar has the highestK _Ic value. Cleavage was the dominant fracture mechanism in the duplex microstructure material. In contrast, for the full lamellar microstructure the high anisotropy of deformation and the large strain discontinuity at grain boundaries resulting in decohesion of grain boundaries are the main fracture processes. Project supported by the National Natural Science Foundation of China and National Advanced Materials Committee of China Synopsis of the first author Chen Xiaoqun, associated professor, born in Jan. 1965, current research fields: physical metallurgy of high-temperature structural intermetallic compounds.     

Microscopic characteristics of different fracture modes of brittle rock

Ａｓｕｒｖｅｙｏｆｆｒａｃｔｕｒｅｍｅｃｈａｎｉｃｓｌｉｔｅｒａｔｕｒｅｒｅ ｖｅａｌｓｔｈａｔｒｅｓｅａｒｃｈｗｏｒｋｏｎｒｏｃｋｆｒａｃｔｕｒｅｍｅｃｈａｎ ｉｃｓｈａｓｍａｉｎｌｙｆｏｃｕｓｅｄｏｎＭｏｄｅⅠｆｒａｃｔｕｒｅ (ｏｐｅｎ ｉｎｇｍｏｄｅ) ,ｉｎｐａｒｔｉｃｕｌａｒ,ｏｎＭｏｄｅⅠｆｒａｃｔｕｒｅｔｏｕｇｈｎｅｓｓｔｅｓｔｉｎｇ[1 2 ] .Ｈｏｗｅｖｅｒ,ｐｒｅ ｅｘｉｓｔｉｎｇｃｒａｃｋｓｉｎｒｏｃｋｍａｔｅｒｉａｌｓｏｒｄｉｓｃｏｎｔｉｎｕｉｔｉｅｓｉｎｒｏｃｋｍａｓｓｅｓａｒｅｓｅ…     

杯芳烃磺酸的应用新进展

简要介绍了两类水溶性杯芳烃---磺化杯芳烃以及磺化硫代杯芳烃的合成,合成过程虽经多步处理,但合成方案较成熟,处理过程简单;其次概述了磺化杯芳烃的热稳定性,该性质为后续的应用研究提供了很好的基础条件,并着重综述了磺化杯芳烃在催化方面的应用,其较强的酸性基团满足了催化反应中所需的酸性条件,此外,与其他类型的酸催化剂相比,磺化杯芳烃易于从反应混合物中分离回收再利用,是一种绿色有机催化剂;最后在配位作用、络合包结、分子离子的识别等作用中作为母体化合物,其应用性能表现良好。     

超重力旋转填充床脱除CO_2体积传质系数的研究

超重力技术应用于有机胺溶液吸收CO2是一项突破性新技术,体积传质系数KGa是衡量填料塔性能高低的重要参数.建立了填料床中气液间体积传质模型,推导出体积传质系数的数学表达式,搭建了实验台以探究转子转速、气体流量、吸收液流量、温度变化对气液间体积传质系数的影响.实验结果表明,合适的工况条件对提高气液间的体积传质系数非常重要.     

Microscopic phase-field simulation for coarsening behavior of L12 and DO22 phases of Ni75Cr x Al25? x alloy

Based on the microscopic phase-field dynamic model and the microelasticity theory, the coarsening behavior of L1₂ and DO₂₂ phases in Ni₇₅Cr _x Al_25−x alloy was simulated. The results show that the initial irregular shaped, randomly distributed L1₂ and DO₂₂ phases are gradually transformed into cuboidal shape with round corner, regularly aligned along directions [100] and [001], and highly preferential selected microstructure is formed during the later stage of precipitation. The elastic field produced by the lattice mismatch between the coherent precipitates and the matrix has a strong influence on the coarsening kinetics, and there is no linear relationship between the cube of the average size of precipitates and the aging time, which does not agree with the results predicted by the classical Lifshitz-Slyozov-Wagner. The coarsening processes of L1₂ and DO₂₂ phases are retarded in elastically constrained system. In the concurrent system of L1₂ and DO₂₂ phases, there are two types of coarsening modes: the migration of antiphase domain boundaries and the interphase Ostwald ripening. Foundation item: Project(50671084) supported by the National Natural Science Foundation of China; Project(20070420218) supported by China Postdoctoral Science Foundation     

Crystallization of Fe78Si6B13 Bulk Crystaline/Amorphous （c/a） Composite

A metallic crystalline/amorphous （c/a） bulk composite was prepared by the slow cooling method after remelting the amorphous Fe78Si9B13 ribbon. By X-ray diffraction （XRD）, differential scanning calorimetry （DSC） and scanning electron microscope （SEM）, the composite consists of the primary dendrite α-Ee （without Si） as well as the amorphous matrix. After being anneal at 800 K, the uniform spheroid particles are formed in the c/a composite, which does not form in the amorphous ribbon under the various annealing process. Energy dispersive analysis of X-rays （EDAX）, SEM and XRD were applied to give more detailed information. The formation and evolution of the particle may stimulate the possible application of the Fe-matrix amorphous alloy.     

Preparation and electrochemical studies of Y-doped LiVPO<Subscript>4</Subscript>F cathode materials for lithium-ion batteries

Y-doped LiVPO₄F cathode materials were prepared by a carbothermal reduction(CTR) process. The properties of the Y-doped LiVPO₄F samples were investigated by X-ray diffraction (XRD) and electrochemical measurements. XRD studies show that the Y-doped LiVPO₄F samples have the same triclinic structure as the undoped LiVPO₄F. The Li extraction/insertion performances of Y-doped LiVPO₄F samples were investigated through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra(EIS). The optimal doping content of Y is x=0.04 in LiY _x V_1−x PO₄F system. The Y-doped LiVPO₄F samples show a better cyclic ability. The electrode reaction reversibility is enhanced, and the charge transfer resistance is decreased through the Y-doping. The improved electrochemical performances of the Y-doped LiVPO₄F cathode materials are attributed to the addition of Y³⁺ ion by stabilizing the triclinic structure. Funded by the Sponsor Teams for Innovation in the Construction of Talent Highlands in Guangxi Institutions of Higher Learning(GuiJiaoRen [2007]71), Guangxi Natural Science Foundation(No.0832259), the Research Funds of the Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment Program to Sponsor Teams for Innovation in the Construction of Talent Highlands in Guangxi Institutions of Higher Learning(GuiJiaoRen [2007]71)     

Influence of interfacial strength on the fracture toughness of glass-ceramic matrix composites

Nine kinds of glass-ceramic matrix composites with different compositions and interfacial strength (τ _s) were prepared. The influence of τ _s on the fracture toughness(K _1c) of composites was studied. It was discoved that, for the system no chemical reaction taking place at the interface, K _1c increased proportionally with τ _s increasing at the first stage, then decreased when τ _s reached a certain value. According to this result, a model of relationship between τ _s, thermal mismatch (Δα _r) and K _1c was built up. If a chemical reaction took place and a new phase was formed in the interface, the K _1c of composite was effected by the combination of τ _s, chemical bonding, radial interfacial stress and other factors. Project supported by the National Natural Science Foundation of China Synopsis of the first author Wang Lingsen, professor, born in 1938, current research field: special ceramic and ceramic matrix composite, etc.     

Semi-analytical weight function method for center-cracked circular disk subjected to diametral compression

Ｓｉｎｃｅｔｈｅｃｅｎｔｅｒ ｃｒａｃｋｅｄｃｉｒｃｕｌａｒｄｉｓｋｓｐｅｃｉ ｍｅｎｃａｎｂｅａｖａｉｌａｂｌｅｄｉｒｅｃｔｌｙｆｒｏｍｒｏｃｋｃｏｒｅ ,ａｎｄｍｉｘｅｄ ｍｏｄｅｆｒａｃｔｕｒｅｒａｎｇｉｎｇｆｒｏｍｐｕｒｅｍｏｄｅⅠｔｏａｎｙＫⅡ/ＫⅠ ｒａｔｉｏｃａｎｂｅｅａｓｉｌｙａｃｈｉｅｖｅｄｕｓｉｎｇｔｈｉｓｇｅｏｍｅｔｒｙ ,ｉｔｉｓｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｍｉｘｅｄ ｍｏｄｅｆｒａｃｔｕｒｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｆｂｒｉｔｔｌｅｍａｔｅｒｉａｌｓ .Ｔｈｅｐｒｏｂｌｅｍｃｏ…     

Synthesis and adsorption properties of chitosan-crown ether resins

1　INTRODUCTIONTheeffectiveremovalorrecoveryoftoxicmetalsstillremainsamajortopicofpresentresearch .In creasedawarenessofthetoxicityofmetalshaspromptedtheimplementationofstrictregulationsforitsdisposal,causingtraditionaltreatmentprocessessuchaschemicalprecipitationtoundergochanges .Modernmetal removaltechnologiessuchasionex change ,reverseosmosis ,andmembranesystemsthatproduceeffluentsofbetterqualitymakeitpossibletorecoverandreusemetals[1,2 ] .Chitosan ,whichiseasilyderivedfromchitinbyN de…     

Adsorption of Pb^2＋ on macroporous weak acid adsorbent resin from aqueous solutions： Batch and column studies

The adsorption properties of a novel macroporous weak acid resin (D152) for Pb²⁺ were investigated with chemical methods. The optimal adsorption condition of D152 resin for Pb²⁺ is at pH 6.00 in HAc-NaAc medium. The statically saturated adsorption capacity is 527 mg/g at 298 K. Pb²⁺ adsorbed on D152 resin can be eluted with 0.05 mol/L HCl quantitatively. The adsorption rate constants determined under various temperatures are k _{288 K}=2.22×10⁻⁵ s^t-1, k _{298 K}=2.51×10⁻⁵ s⁻¹, and k _{308 K}= 2.95×10⁻⁵ s⁻¹, respectively. The apparent activation energy, E _a is 10.5 kJ/mol, and the adsorption parameters of thermodynamics are ΔH ^Θ=13.3 kJ/mol, ΔS ^Θ=119 J/(mol·K), and ΔG ^Θ 298 K =−22.2 kJ/mol, respectively. The adsorption behavior of D152 resin for Pb²⁺ follows Langmuir model. Foundation item: Project(2008F70059) supported by the Scientific and Technological Research Planning of Zhejiang Province, China     

Preparation and properties of SrBi2.2 Ta2O9 thin film

SrBi_2.2 Ta₂O₉ (SBT) thin film with thickness of 2 μm was successfully prepared by sol-gel method, using strontium acetate semihydrate [Sr(CH₃ COO)₂ · 1/2H₂O] and bismth subnitrate [BiO(NO₃)], and tantalum ethoxide [Ta(OCH₂CH₃)₅] as source materials, glacial acetic and ethylene glycol as solvents. The X-ray diffraction (XRD) and transmission electron microscope(TEM) results indicate that SBT layer-perovskite phase obtained has to be single phase, SBT thin film is formed after being annealed at 800 °C for for 1 min. The typical hysteresis loop of SBT thin film on Pt/Ti/SiO₂/Si is obtained, and the measured polarization value of the SBT thin film is 4. 2 μ/C/cm². Foundation item: Project (HIT. 2001. 67) supported by the Scientific Research Foundation of Harbin Institute of Technology; project (50172012) supported by the National Natural Science Foundation of China     

Optimal decay rate of vibrating beam equations controlled by combined boundary feedback forces

The optimal decay rate problem is considered for boundary control system modeling by a flexible structure consisting of a Eular-Bernoulli beam. Controls are a bending moment in proportion to angular velocity and a shear force in proportion to velocity. A sensitivity asymptotic analysis of the system' s eigenvalues and eigenfunctions is set up. It is proved that, for every 00, y(0)=Y_0, Y_0=(Y_1,Y_2)~T ∈V×H form a Riesz basis of V×H, and the optimal exponential decay rate can be obtained from the spectrum of the system.     

Thermal Decomposition of Leightonite,K2Ca2Cu（SO4）4·2H2O

The thermal decomposition of Leightonite, K2Ca2Cu（SO4）4·2H2O, was studied by thermal gravimetric analysis（TGA）, differential thermal analysis（DTA）, X-ray diffraction（XRD）, etc. The results show that the Leightonite is dehydrated around 170 ℃ to 390 ℃ and transformed to be new intermediate （K-Cu-SO4） sulphate salt with bright-green color. Moreover, the chemical structure changes during the thernal decomposition process was describled in detail. And the as-resulting phases are demonstrated to be K2Ca2（SO4）3, K2SO4, CaSO4 ,and Cu2O.     

Structures and properties of [CoPt/Ag]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> multilayer fims

The magnetic properties and structures of [CoPt/Ag] _n , multilayer films deposited by DC magnetron sputtering have been studied. During the deposited process, two kinds of deposited sequences, that is Ag layer (FDAG) first deposited or CoPt layer (FDCP) first deposited, have been chosen. The results show that the microstructures and coercivities were strongly influenced by the deposited sequence and the thickness of films. The coercivities of [Ag/CoPt] _n with FDAG are obviously higher than those of [CoPt/Ag] _n with FDCP. Especially, when the thickness of films is 8 nm, the difference of coercivities between the FDAG film and the FDCP film is the largest. It is possibly because Ag plays a role of underlayer in FDAG multilayers, which can induce both the transformation from fcc to fct and the oriented growth along c-axis. In addition, δM curves reveal that the [CoPt/Ag]₈ multilayer, film has a lower intergrain interaction than the CoPt/Ag bilayer film.