Measurements Of In Situ Stress And Mining-Induced Stress In Beiminghe Iron Mine Of China

In order to obtain the distribution rules of in situ stress and mining-induced stress of Beiminghe Iron Mine, the stress relief method by overcoring was used to measure the in situ stress, and the MC type bore-hole stress gauge was adopted to measure the mining-induced stress. In the in situ stress measuring, the technique of improved hollow inclusion cells was adopted, which can realize complete temperature compensation. Based on the measuring results, the distribution model of in situ stress was established and analyzed. The in situ stress measuring result shows that the maximum horizontal stress is 1.75-2.45 times of vertical stress and almost 1.83 times of the minimum horizontal stress in this mineral field. And the mining-induced stress measuring result shows that, according to the magnitude of front abutment pressure the stress region can be separated into stress-relaxed area, stress-concentrated area and initial stress area. At the -50 m mining level of this mine, the range of stress-relaxed area is 0-3 m before mining face; the range of stress-concentrated area is 3-55 m before mining face, and the maximum mining-induced stress is 16.5-17.5 MPa, which is 15-20 m from the mining face. The coefficient of stress concentration is 1.85.

Molecular cloning and characterization of the copper/zinc and manganese superoxide dismutase genes from the human parasite Clonorchis sinensis

A copper/zinc superoxide dismutase (Cu/ZnSOD) gene and a manganese superoxide dismutase (MnSOD) gene of the human parasite Clonorchis sinensis have been cloned and their gene products functionally characterized. Genes Cu/ZnSOD and MnSOD encode proteins of 16 kDa and 25.4 kDa, respectively. The deduced amino acid sequences of the two genes contained highly conserved residues required for activity and secondary structure formation of Cu/ZnSOD and MnSOD, respectively, and show up to 73.7% and 75.4% identities with their counterparts in other animals. The genomic DNA sequence analysis of Cu/ZnSOD gene revealed this as an intronless gene. Inhibitor studies with purified recombinant Cu/ ZnSOD and MnSOD, both of which were functionally expressed in Escherichia coli, confirmed that they are copper/zinc and manganese-containing SOD, respectively. Immunoblots showed that both C. sinensis Cu/ZnSOD and MnSOD should be antigenic for humans, and both, especially the C. sinensis MnSOD, exhibit extensive cross-reactions with sera of patients infected by other trematodes or cestodes. RT-PCR and SOD activity staining of parasite lysates indicate that there are no significant differences in mRNA level or SOD activity for both species of SOD, indicating cytosolic Cu/ZnSOD and MnSOD might play a comparatively important role in the C. sinensis antioxidant system.

Interfacial electronic structure of copper phthalocyanine and copper hexadecafluorophthalocyanine studied by photoemission

Electronic structures of the heterojunction between copper phthalocyanine (CuPc) and copper hexadecafluorophthalocyanine (F16CuPc) were studied with ultraviolet photoemission spectroscopy. Band bending and an interface dipole were observed at the interface due to the formation of an electron accumulation layer and a depletion layer in F16CuPc and CuPc, respectively. Such an energy level alignment leads to interesting ambipolar characteristics for application of the CuPc/F16CuPc junction in organic field-effect transistors.

Study on mixed Langmuir-Blodgett film of tri-(2,4-di-t-amylphenoxy)-(8-quinolinolyl)copper phthalocyanine and water-soluble fullerenols

Mixed Langmuir-Blodgett films of tri-(2,4-di-t-amylphenoxy)-(8-quinolinolyl) copper phthalocyanine and water-soluble fullerenols are prepared. Their behavior at the air-water interface and the monolayer morphology are studied. (C) 1998 Elsevier Science Limited. All rights reserved.

Biosorption of copper (II) and lead (II) from aqueous solutions by nonliving green algae Cladophora fascicularis: Equilibrium, kinetics and environmental effects

Biosorption of Cu2+ and Pb2+ by Cladophora fascicularis was investigated as a function of initial pH, initial heavy metal concentrations, temperature and other co-existing ions. Adsorption equilibriums were well described by Langmuir and Freundlich isotherm models. The maximum adsorption capacities were 1.61 mmol/ g for Cu2+ and 0.96 mmol/ g for Pb2+ at 298K and pH 5.0. The adsorption processes were endothermic and biosorption heats calculated by the Langmuir constant b were 39.0 and 29.6 kJ/ mol for Cu2+ and Pb2+, respectively. The biosorption kinetics followed the pseudo- second order model. No significant effect on the uptake of Cu2+ and Pb2+ by co-existing cations and anions was observed, except EDTA. Desorption experiments indicated that Na(2)EDTA was an efficient desorbent for the recovery of Cu2+ and Pb2+ from biomass. The results showed that Cladophora fascicularis was an effective and economical biosorbent material for the removal and recovery of heavy metal ions from wastewater.

Preparation of Dendritic Copper Nanostructures and Their Characterization for Electroreduction

Dendritic copper nanostructures of different morphologies were synthesized by a surfactant-free electrochemical method. Single crystal nature of the nanostructures was revealed from their X-ray diffraction and electron diffraction patterns. Mechanism of dendrite formation was discussed from thermodynamic aspects using the concept of supersaturation. Supersaturation of the copper metal reduced on the surface of the electrode was the crucial factor for the generation of different morphologies. Effects of applied potential, temperature, and the solution concentration on the supersaturation were studied. The NO3- and H2O2 electroreduction ability of the dendritic materials was tested. Use of copper dendrite-modified electrode as NO3- sensor was demonstrated.

Preparation and characterization of a novel macrocyclic ligand—dinitro-tetraazacyclotetradeca-tetraene—and application as a highly selective extractant for copper(II)

A novel tetraaza macrocyclic Schiff base ligand, 6,13-dinitro-5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,5,7,-12-tetraene, was prepared and its copper(II) and nickel(II) complexes were characterized. This ligand was found to be an excellent extractant for copper(II).

Oxamido-bridged heterobinuclear copper(II)-nickel(II) complex and homotrinuclear nickel(II) complex with 2D supramolecular structure: synthesis, crystal structure, magnetic and spectroscopic properties

The oxamido-bridged heterobinuclear copper(II)-nickel(II) complex, [Cu(oxbe)Ni(phen)(2)]ClO4.3H(2)O (1) and homotrinuclear nickel(11) complex {[Ni(oxbe)](2)Ni(H2O)(2)}.2.5DMF (2) have been synthesized and characterized by means of elemental analysis, IR, EPR. and electronic spectra and magnetic susceptibility, where H(3)oxbe is dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)ox-amido, phen = 1.10-phenanthroline, DMF = dimethylformamide. Complex I has an extended oxamido-bridged structure consisting of planar copper(II) and octahedral nickel(II) ions. The chi(M) and mu(eff) versus T plots of 1 is typical of an antiferromagnetically coupled Cu(II)-Ni(II,) pair with a spin-doublet ground state, and magnetic analysis leads to J = -57.1 cm(-1). The molecular structure of 2 is centrosymmetrical, with one octahedral nickel atom lying at an inversion center and two terminal Ni(II) atoms in approximately square planar environment. Through the hydrogen bonds and pi- pi stacking interactions, a 2D supramolecular structure is formed.

CYCLIC VOLTAMMETRIC AND SPECTROELECTROCHEMICAL STUDIES OF COPPER IN ALKALINE-SOLUTION

The behaviour of the electroplated copper film electrode on tin oxide/glass or glassy carbon surface was studied in potassium hydroxide medium by cyclic voltammetry and in situ transmission spectroelectrochemistry. The results indicate that the electroplated copper film electrode is similar to a copper electrode and cyclic voltammetry with this electrode affords more resolution. The anodic peaks were found to correspond successively to the adsorption of oxygen, the formation of a surface layer of Cu2O, the formation of a surface layer of Cu(OH)2 or CuO and formation of a thick multilayer film of CuO. This is the first time it has been proposed that a surface layer of Cu(OH)2 or CuO is formed from the oxidation of the surface layer of Cu2O. Similarly, a clear interpretation is presented that the cathodic peaks correspond successively to the reduction of CuO to Cu2O, the reductions of Cu2O to Cu and the soluble Cu(II) species to Cu. On the other hand, a shoulder peak related to the chemical transformation of Cu(OH)2 to CuO was first observed.

Absorption characteristic and nonvolatile holographic recording in LiNbO3 : Cr : Cu crystals

The absorption characteristic of lithium niobate crystals doped with chromium and copper (Cr and Cu) is investigated. We find that there are two apparent absorption bands for LiNbO3:Cr:Cu crystal doped with 0.14 wt.% Cr2O3 and 0.011 wt.% CuO; one is around 480 nm, and the other is around 660 nm. With a decrease in the doping composition of Cr and an increase in the doping composition of Cu, no apparent absorption band in the shorter wavelength range exists. The higher the doping level of Cr, the larger the absorbance around 660 nm. Although a 633 nm red light is located in the absorption band around 660 nm, the absorption at 633 nm does not help the photorefractive process; i.e., unlike other doubly doped crystals, for example, LiNbO3:Fe:Mn crystal, a nonvolatile holographic recording can be realized by a 633 nm red light as the recording light and a 390 nm UV light as the sensitizing light. For LiNbO3:Cr:Cu crystals, by changing the recording light from a 633 nm red light to a 514 nm green light, sensitizing with a 390 nm UV light and a 488 nm blue light, respectively, a nonvolatile holographic recording can be realized. Doping the appropriate Cr (for example, N-Cr = 2.795 X 10(25)m(-3) and N-Cr/N-Cu = 1) benefits the improvement of holographic recording properties. (c) 2005 Optical Society of America.

First-principle study of native defects in CuScO2 and CuYO2

This paper studies the electronic structure and native defects intransparent conducting oxides CuScO2 and CuYO2 using the first-principle calculations. Some typical native copper-related and oxygen-related defects, such as vacancy, interstitials, and antisites in their relevant charge state are considered. The results of calculation show that, CuMO2 (M = Sc, Y) is impossible to shown-type conductivity ability. It finds that copper vacancy and oxygen interstitial have relatively low formation energy and they are the relevant defects in CuScO2 and CuYO2. Copper vacancy is the most efficient acceptor, and under O-rich condition oxygen antisite also becomes important acceptor and plays an important role in p-type conductivity.

Turn-on fluorescent cyanide sensor based on copper ion-modified CdTe quantum dots

A new fluorescent sensor for the sensitive and selective detection of cyanide (CN-) in aqueous media was developed herein. The sensing approach is based on CN--modulated quenching behavior of Cu2+ toward the photoluminescence (PL) of CdTe quantum dots (QDs). In the presence of CN-, the PL of QDs that have been quenched by Cu2+ was found to be efficiently recovered, which then allows the detection of CN- in a very simple approach. Experimental results showed that the pH of the buffer solution, concentration of copper ions, and size of CdTe QDs all influenced the response of the sensor to CN-. Under the optimal conditions, a good linear relationship between the PL intensity and the concentration of CN- can be obtained in the range of 3.0 x 10(-7) to 1.2 x 10(-5) M, with a detection limit as low as 1.5 x 10(-7) M. In addition, the present fluorescent sensor possesses remarkable selectivity for cyanide over other anions, and negligible influences were observed on the cyanide detection by the coexistence of other anions or biological species (such as albumin and typical blood constituents).

Synthesis and self-assembly of cetyltrimethylammonium bromide-capped gold nanoparticles

In this article, cetyltrimethylammonium bromide (CTAB)-capped gold nanoparticles were synthesized successfully by using CTAB as a phase-transfer catalyst and stabilizer simultaneously in a two-phase toluene/water system. The as-prepared gold nanoparticles were characterized and analyzed by virtue of X-ray photoelectron spectroscopy, UV-visible absorbance spectroscopy, and infrared spectroscopy. The particle size information and collective self-assembling properties of the CTAB-capped gold nanoparticles on carbon-coated copper grid and mica were evaluated by transmission electron microscopy and atomic force microscopy, respectively. As a result it is demonstrated that the 3-D CTAB monolayers on a gold cluster are in the disordered liquid state. The interparticle spacing can be controlled either physically by the inherent particle-to-particle interactions or chemically by molecular linker. The assembly of both nanoparticles and linker-bridged nanonetworks on mica follows a hydrophobic interaction mechanism.