Extraction of V（V） and Cr（III） from acidic sulfate leach liquors of ilmenite using 0.4 mol/L Aliquat 336 chloride in kerosene was carried out. Different parameters affecting the extraction process such as equilibr...Extraction of V（V） and Cr（III） from acidic sulfate leach liquors of ilmenite using 0.4 mol/L Aliquat 336 chloride in kerosene was carried out. Different parameters affecting the extraction process such as equilibrium time, sulfate concentration, Aliquat 336 concentration, equilibrium p H and the extraction temperature were investigated. Extraction of V（V） and Cr（III） by Aliquat 336 involved anion exchange mechanism, and the extracted species are [（VO2SO4）R4N]org at low equilibrium p H for V（V） and [R4N-Cr（OH）4]org at high equilibrium p H for Cr（III）. Calculated thermodynamic parameters show that the extraction process is endothermic reaction for V（V） and exothermic for Cr（III）. Also, calculated values of ？Gex and ？Sex indicate that the extraction reactions of V（V） and Cr（III） proceed as non-spontaneous reaction is more random. V（V） and Cr（III） were stripped, precipitated, separated and calcined at 500 °C for 2.0 h to produce the corresponding oxide in pure form after rinsing and drying.展开更多
The paper proposed an improved Ordered Successive Interference Cancellation(OSIC) detection scheme for V-BLAST systems with square/rectangular Quadrature Amplitude Modulation(QAM) modulation.It utilizes an equivalent ...The paper proposed an improved Ordered Successive Interference Cancellation(OSIC) detection scheme for V-BLAST systems with square/rectangular Quadrature Amplitude Modulation(QAM) modulation.It utilizes an equivalent real-valued vector expression of relationship between transmit signals and received signals,exploits the constellation's product-form structure and can eventually make the order,in which components of the transmit signals vector are extracted,more "optimal" in some sense.Thereby,it can offer an improved error probability as compared to the conventional OSIC detection scheme.In addition,the paper also proposes an efficient projection al-gorithm to calculate nulling vectors in a simple recursive fashion in order to avoid the vast increase of complexity,which is due to the fact that the original complex N -dimensional data vector and M×N channel matrix are transformed into a real 2N -dimensional data vector and a real 2M ×2N channel matrix respectively.A scrutinous complexity analysis shows that the complexity increases by only 33% as compared to the conventional scheme.展开更多
We used bovine cornea as starting material, pepsin treatment in acetic acid solution to extract the mixture of type I and V collagens, and salt precipitation and dialysis to purify and isolate each type of the collage...We used bovine cornea as starting material, pepsin treatment in acetic acid solution to extract the mixture of type I and V collagens, and salt precipitation and dialysis to purify and isolate each type of the collagens. The preparation was analyzed using sodium dodecyl sulphate polyacrylamide gel electrophoresis. 2-mercaptoethanol used as reducing agent cut off the disulfide bonds, which was utilized to analyze the structure of disulfide bonds involved between α chains in some types of collagens. At the same time, we discovered that the structure of disulfide bonds among α chains potentially existed in the type V collagen prepared from the pepsin-treatment extraction at 4℃. Through quantitative analysis, we obtained that, compared with those pepsin-treated at 4℃, the relative molecular weights of α1 （V） and α 2 （V） subunits pepsin-treated at room temperature decreased by 4.6% and 6.0%, respectively. It is concluded that type V collagen can be prepared from bovine coruea by use of pepsin treatment, salt precipitation and dialysis. The interchain and/or intermolecular disulfide bonds potentially lie near the edges of termini of type V collagen molecules existing in extracellular matrix, and there are few of the intermolecular and/or intramolecular crosslinks formed by lysine or hydroxylysine or histidine residues in type V collagen.展开更多
文摘Extraction of V（V） and Cr（III） from acidic sulfate leach liquors of ilmenite using 0.4 mol/L Aliquat 336 chloride in kerosene was carried out. Different parameters affecting the extraction process such as equilibrium time, sulfate concentration, Aliquat 336 concentration, equilibrium p H and the extraction temperature were investigated. Extraction of V（V） and Cr（III） by Aliquat 336 involved anion exchange mechanism, and the extracted species are [（VO2SO4）R4N]org at low equilibrium p H for V（V） and [R4N-Cr（OH）4]org at high equilibrium p H for Cr（III）. Calculated thermodynamic parameters show that the extraction process is endothermic reaction for V（V） and exothermic for Cr（III）. Also, calculated values of ？Gex and ？Sex indicate that the extraction reactions of V（V） and Cr（III） proceed as non-spontaneous reaction is more random. V（V） and Cr（III） were stripped, precipitated, separated and calcined at 500 °C for 2.0 h to produce the corresponding oxide in pure form after rinsing and drying.
基金the National Natural Science Foundation of China(No.60272009,No.60572090,No.60472045 and No.60496313)
文摘The paper proposed an improved Ordered Successive Interference Cancellation(OSIC) detection scheme for V-BLAST systems with square/rectangular Quadrature Amplitude Modulation(QAM) modulation.It utilizes an equivalent real-valued vector expression of relationship between transmit signals and received signals,exploits the constellation's product-form structure and can eventually make the order,in which components of the transmit signals vector are extracted,more "optimal" in some sense.Thereby,it can offer an improved error probability as compared to the conventional OSIC detection scheme.In addition,the paper also proposes an efficient projection al-gorithm to calculate nulling vectors in a simple recursive fashion in order to avoid the vast increase of complexity,which is due to the fact that the original complex N -dimensional data vector and M×N channel matrix are transformed into a real 2N -dimensional data vector and a real 2M ×2N channel matrix respectively.A scrutinous complexity analysis shows that the complexity increases by only 33% as compared to the conventional scheme.
文摘We used bovine cornea as starting material, pepsin treatment in acetic acid solution to extract the mixture of type I and V collagens, and salt precipitation and dialysis to purify and isolate each type of the collagens. The preparation was analyzed using sodium dodecyl sulphate polyacrylamide gel electrophoresis. 2-mercaptoethanol used as reducing agent cut off the disulfide bonds, which was utilized to analyze the structure of disulfide bonds involved between α chains in some types of collagens. At the same time, we discovered that the structure of disulfide bonds among α chains potentially existed in the type V collagen prepared from the pepsin-treatment extraction at 4℃. Through quantitative analysis, we obtained that, compared with those pepsin-treated at 4℃, the relative molecular weights of α1 （V） and α 2 （V） subunits pepsin-treated at room temperature decreased by 4.6% and 6.0%, respectively. It is concluded that type V collagen can be prepared from bovine coruea by use of pepsin treatment, salt precipitation and dialysis. The interchain and/or intermolecular disulfide bonds potentially lie near the edges of termini of type V collagen molecules existing in extracellular matrix, and there are few of the intermolecular and/or intramolecular crosslinks formed by lysine or hydroxylysine or histidine residues in type V collagen.
