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1991 Volume 7 Issue 4
1991, 7(04): 385-389
doi: 10.3866/PKU.WHXB19910401
Abstract:
1991, 7(04): 390-393
doi: 10.3866/PKU.WHXB19910402
Abstract:
In the molecular dynamics study of the superionic conductor CaF_2, the structures of Ca~(2+) sublattice and F~- sublattice have been investigated based on the bond spherical harmonies method. The simulation temperatures are 1400, 1590 and 2000K and the pair potential used in the simulation is Born-Huggins-Mayer (BHM)potential. The bond order parameters Q_l have been calculated both for the computer-generated instantaneuos configurations from the simulation system and for the standard configurations from the normal distribution model of bond orientation. The comparison of Q_l between the molecular dynamics simulation and the normal distribution model shows that not only Ca~(2+) ions keep their original FCC frame stably, but in the F~- case there is a great deal of deformation at random from the original F~- sublattice.
In the molecular dynamics study of the superionic conductor CaF_2, the structures of Ca~(2+) sublattice and F~- sublattice have been investigated based on the bond spherical harmonies method. The simulation temperatures are 1400, 1590 and 2000K and the pair potential used in the simulation is Born-Huggins-Mayer (BHM)potential. The bond order parameters Q_l have been calculated both for the computer-generated instantaneuos configurations from the simulation system and for the standard configurations from the normal distribution model of bond orientation. The comparison of Q_l between the molecular dynamics simulation and the normal distribution model shows that not only Ca~(2+) ions keep their original FCC frame stably, but in the F~- case there is a great deal of deformation at random from the original F~- sublattice.
1991, 7(04): 394-395
doi: 10.3866/PKU.WHXB19910403
Abstract:
Both positive and negative InP cluster ions were generated on a self-built laser probe time-of-flight mass spectrometer. The negative mass spectra showed an alternation of the cluster ion intensities with the odd/even total number of atoms in the clusters. This result is attributed to that all the valence electrons in the clusters of odd atom number are paired, thus stable. It is proposed that, based on the above result, the stability of such cluster ions depends more on their electronic structures than on their geometric structures. Further studies on both theoritical computation and experimentation are being carried on.
Both positive and negative InP cluster ions were generated on a self-built laser probe time-of-flight mass spectrometer. The negative mass spectra showed an alternation of the cluster ion intensities with the odd/even total number of atoms in the clusters. This result is attributed to that all the valence electrons in the clusters of odd atom number are paired, thus stable. It is proposed that, based on the above result, the stability of such cluster ions depends more on their electronic structures than on their geometric structures. Further studies on both theoritical computation and experimentation are being carried on.
1991, 7(04): 396-399
doi: 10.3866/PKU.WHXB19910404
Abstract:
Tight-binding band calculations of the Extended Huckel type were performed on the modulated Bi_2Sr_2CuO_6 sublattice in contrast with those for the average structure. It is shown that the structural modulation weakens Bi-O autibonding interactions, leading to a splitting of Bi 6P states and a shift of Bi 6p-block bands toward lower energy region. Such a shift favors the formation of the electron pocket of the Bi 6p-block bands thereby strengthening the oxidation of the CuO2 sheets.
Tight-binding band calculations of the Extended Huckel type were performed on the modulated Bi_2Sr_2CuO_6 sublattice in contrast with those for the average structure. It is shown that the structural modulation weakens Bi-O autibonding interactions, leading to a splitting of Bi 6P states and a shift of Bi 6p-block bands toward lower energy region. Such a shift favors the formation of the electron pocket of the Bi 6p-block bands thereby strengthening the oxidation of the CuO2 sheets.
1991, 7(04): 400-403
doi: 10.3866/PKU.WHXB19910405
Abstract:
Chemical modeling studies of ATP driven electron-transfer in Nitrogenase reaction show that adenylate compounds can complex with [Fe_4S_4(SPh)_4]~(2-) cluster, resulting in down field shifting of the ~(31)P NMR peaks of α-、β- and γ-PO_4 about 13.2ppm. 8.3ppm and 28.3ppm, respectively (in its DMF-D_2O(3:2v/v) solution). in down-field shifting of the ~(31)p NMR peaks of a-and β-PO_4 of ADP by about 15.77ppm and 2.71ppm respectively. (in DMF-D_2O (3:2v/v) solution). The above experimental results is quite similar to the observations of Mortenson et al in Fe-protein system. This may be taken as the strong evidence for supporting the view that all of the MgATP and the MgADP can coordinate to the Fe_4S_4~* center of the Fe-protein through the PO_4 groups, rather than other parts of theprotein.
Chemical modeling studies of ATP driven electron-transfer in Nitrogenase reaction show that adenylate compounds can complex with [Fe_4S_4(SPh)_4]~(2-) cluster, resulting in down field shifting of the ~(31)P NMR peaks of α-、β- and γ-PO_4 about 13.2ppm. 8.3ppm and 28.3ppm, respectively (in its DMF-D_2O(3:2v/v) solution). in down-field shifting of the ~(31)p NMR peaks of a-and β-PO_4 of ADP by about 15.77ppm and 2.71ppm respectively. (in DMF-D_2O (3:2v/v) solution). The above experimental results is quite similar to the observations of Mortenson et al in Fe-protein system. This may be taken as the strong evidence for supporting the view that all of the MgATP and the MgADP can coordinate to the Fe_4S_4~* center of the Fe-protein through the PO_4 groups, rather than other parts of theprotein.
1991, 7(04): 404-408
doi: 10.3866/PKU.WHXB19910406
Abstract:
An irreducible tensor method based on restricted Hartree-Fock method for calculating many-electron states and energy levels of valence electron system is presented. By means of this method, the electronic structures of the following octahedral transition metal complexes have been studied: CrCl_6~(3-), CrF_6~(3-), CrO_6~(9-), Cr(H_2O)_6~(3+), Cr(NH_3)_6~(3+), Cr(CN)_6~(3-). The calculated excitation energies agree with the observed ones within several kcm~(-1).
An irreducible tensor method based on restricted Hartree-Fock method for calculating many-electron states and energy levels of valence electron system is presented. By means of this method, the electronic structures of the following octahedral transition metal complexes have been studied: CrCl_6~(3-), CrF_6~(3-), CrO_6~(9-), Cr(H_2O)_6~(3+), Cr(NH_3)_6~(3+), Cr(CN)_6~(3-). The calculated excitation energies agree with the observed ones within several kcm~(-1).
1991, 7(04): 409-412
doi: 10.3866/PKU.WHXB19910407
Abstract:
Electrochemical and photoeletrochemical properties of electrodepositing γ-MnO_2 are studied when it is charged and discharged in 1 mol·L~(-3) KOH using cyclic voltammetry and in-situ photoelectrochemical method. When γ-MnO_2 is reduced,the photocurrent decreases from positive to negative. We concluded that γ-MnO_2 is a n-type semiconductor, but it is p-type doped during the reduction processes.
Electrochemical and photoeletrochemical properties of electrodepositing γ-MnO_2 are studied when it is charged and discharged in 1 mol·L~(-3) KOH using cyclic voltammetry and in-situ photoelectrochemical method. When γ-MnO_2 is reduced,the photocurrent decreases from positive to negative. We concluded that γ-MnO_2 is a n-type semiconductor, but it is p-type doped during the reduction processes.
1991, 7(04): 413-419
doi: 10.3866/PKU.WHXB19910408
Abstract:
Cationic-anionic surfactants have a high surface activity. But they are liable to precipitate as the concetration is slightly over cme, so their utilities are restricted. This paper describes their various surface properties and solubility phenomena when zwitterionic surfactant is mixed with them. The results indicate that (1) Owing to solubilization by the zwitterionic surfactant, the solubility of cationic-anionic surfactants is increased. (2) Proper amount of zwitterionic surfactant may keep the surface activity of the cationic-anionic surfactant essentially to be constant. (3) The molecular interaction between cationic-anionic and zwitterionic surfactants is stronger than that between cationic-anionic and nonioic surfactants in both surface layer and micelle; for HC-FC cationic-anionic and zwitterionic systems the saturated adsorption film possibly have a double-or multilayer structure.
Cationic-anionic surfactants have a high surface activity. But they are liable to precipitate as the concetration is slightly over cme, so their utilities are restricted. This paper describes their various surface properties and solubility phenomena when zwitterionic surfactant is mixed with them. The results indicate that (1) Owing to solubilization by the zwitterionic surfactant, the solubility of cationic-anionic surfactants is increased. (2) Proper amount of zwitterionic surfactant may keep the surface activity of the cationic-anionic surfactant essentially to be constant. (3) The molecular interaction between cationic-anionic and zwitterionic surfactants is stronger than that between cationic-anionic and nonioic surfactants in both surface layer and micelle; for HC-FC cationic-anionic and zwitterionic systems the saturated adsorption film possibly have a double-or multilayer structure.
1991, 7(04): 420-424
doi: 10.3866/PKU.WHXB19910409
Abstract:
The structures of CH_5O~+ from two different reactions which are protonation of CH_3OH and association of CH_3~+ with water were studied by means of CID experiment and MNDO semiempirical calculation The results showed that the CH_5O~+ ions produced from the above two pathways possess the same structure,CH_3OH_2~+.The value of kinetic energy release for the metastable decomposition CH_3OH_2~+→CH_2OH~++H_2 determined from the experiment is in od agreement with that from theoretical calculations. The transition state of above reaction were disscussed.
The structures of CH_5O~+ from two different reactions which are protonation of CH_3OH and association of CH_3~+ with water were studied by means of CID experiment and MNDO semiempirical calculation The results showed that the CH_5O~+ ions produced from the above two pathways possess the same structure,CH_3OH_2~+.The value of kinetic energy release for the metastable decomposition CH_3OH_2~+→CH_2OH~++H_2 determined from the experiment is in od agreement with that from theoretical calculations. The transition state of above reaction were disscussed.
1991, 7(04): 425-429
doi: 10.3866/PKU.WHXB19910410
Abstract:
Positron annihilation measurements have been carried ont for Y zeolites with different types of cations, faujasites with different Si/Al ratios and zeolites with different structures. The o-Ps annihilation lifetimes are closely correlated with the variations of the electrostatic field in the zeolites. The o-Ps lifetimes are shortened when the electrostatic field in the zeolites is increased. Positron annihilation data show that the electrostatic field of cation-exchanged Y zeolites varies in the order of KY<NaY<BaY<CaY<CeY. As the Si/Al ratio of the faujasites increases the annihilation lifetimes are decreased, because the electrostatic field in the zeolite is increased owing to the diminished shielding from the neighboring cations. For zeolites with different structures and pore sizes the o-Ps annihilation lifetime on the surface is affected mainly by the variation of the electrostatic field in the zeolites, while the o-Ps annihilation lifetime in the cages depends distinctly on the zeolite pore size. The o-Ps annihilation lifetime in the cages is directly proportional to the average pore size of the zeolites. This linear relationship between the o-P annihilation lifetime and the average pore size may be utilized to estimate quickly the pore size of zeolites with unknown structure.
Positron annihilation measurements have been carried ont for Y zeolites with different types of cations, faujasites with different Si/Al ratios and zeolites with different structures. The o-Ps annihilation lifetimes are closely correlated with the variations of the electrostatic field in the zeolites. The o-Ps lifetimes are shortened when the electrostatic field in the zeolites is increased. Positron annihilation data show that the electrostatic field of cation-exchanged Y zeolites varies in the order of KY<NaY<BaY<CaY<CeY. As the Si/Al ratio of the faujasites increases the annihilation lifetimes are decreased, because the electrostatic field in the zeolite is increased owing to the diminished shielding from the neighboring cations. For zeolites with different structures and pore sizes the o-Ps annihilation lifetime on the surface is affected mainly by the variation of the electrostatic field in the zeolites, while the o-Ps annihilation lifetime in the cages depends distinctly on the zeolite pore size. The o-Ps annihilation lifetime in the cages is directly proportional to the average pore size of the zeolites. This linear relationship between the o-P annihilation lifetime and the average pore size may be utilized to estimate quickly the pore size of zeolites with unknown structure.
1991, 7(04): 430-435
doi: 10.3866/PKU.WHXB19910411
Abstract:
The ion exchange isotherms, the corrected selectivity coefficients and the rational thermodynamic equilibrium constants of the weak base anion resin 710A have been determined for the SO_4~(2-)-Cl~-, NO_3~--Cl~- and NO_3~--SO_4~(2-) systems at 25 ℃. The comparsion of the ion exchange equilibria between the weak and the strong base anion resins were reported. The affinity sequence of the strong and the weak base anion resins for the sulphate, nitrate and chloride are in agreement with the theoretical predictions. The SO_4~(2-)-Cl~--NO_3~- system ternary isotherm was also determined on the weak base anion resin 710A at 25 ℃. The predictions of the ternary system based solely on the binary data are consistent with the experimental data found for this system as did for the SO_4~(2-)-Cl~--NO_3~- -strong base anion resin system.
The ion exchange isotherms, the corrected selectivity coefficients and the rational thermodynamic equilibrium constants of the weak base anion resin 710A have been determined for the SO_4~(2-)-Cl~-, NO_3~--Cl~- and NO_3~--SO_4~(2-) systems at 25 ℃. The comparsion of the ion exchange equilibria between the weak and the strong base anion resins were reported. The affinity sequence of the strong and the weak base anion resins for the sulphate, nitrate and chloride are in agreement with the theoretical predictions. The SO_4~(2-)-Cl~--NO_3~- system ternary isotherm was also determined on the weak base anion resin 710A at 25 ℃. The predictions of the ternary system based solely on the binary data are consistent with the experimental data found for this system as did for the SO_4~(2-)-Cl~--NO_3~- -strong base anion resin system.
1991, 7(04): 436-442
doi: 10.3866/PKU.WHXB19910412
Abstract:
The kinetics of oxygen-uptake in DMF medium for MPc and MTPP catalytic systems has been investigated by means of measuring the absorbance variation vs time. According to a consecutive reactive mechanism, the activities of MP catalytic systems are in the order.
MPc>MTPP; Fe>Co>Cu
The reaction rates of MTPP with oxygen in air are less than that with pure oxygen, the ratio is roughly the same as to the partial pressure of oxygen in air. The influences of S-ligand ethanethiol and O-ligand Vc on the above systems have also been investigated, the former makes the MP bands having more changes and the reaction rate constants becoming greater, the latter has less influence.
The kinetics of oxygen-uptake in DMF medium for MPc and MTPP catalytic systems has been investigated by means of measuring the absorbance variation vs time. According to a consecutive reactive mechanism, the activities of MP catalytic systems are in the order.
MPc>MTPP; Fe>Co>Cu
The reaction rates of MTPP with oxygen in air are less than that with pure oxygen, the ratio is roughly the same as to the partial pressure of oxygen in air. The influences of S-ligand ethanethiol and O-ligand Vc on the above systems have also been investigated, the former makes the MP bands having more changes and the reaction rate constants becoming greater, the latter has less influence.
1991, 7(04): 443-448
doi: 10.3866/PKU.WHXB19910413
Abstract:
The model proposed in previous paper was applied to metal/(mixed-solvents) solution system. According to this model, the solvation monolayer at the charged metal surface was formed by competitive adsorption of composed solvent molecules, and the dipole orientation of every solvent molecules was considered to be present in three probable states, namely, A(r)-negative end towards the metal, B(r)-positive end towards the metal, and C(r)-the dipole vector oriented at an angle Ψ(r) to the direction of electric field. Assuming the dipole orientation distribution for this adsorption layer obeys Bragg-Williams approximation and three distinctive oriented states may be converted to each other, then the mixed-adsorption isotherm could be derived by using the statistical mechanical method together with the thermodynamic equilibrium conditions.
Using the equilibrium relations mentioned above and the expression for potential drop acrossed the monolayer regions, the inner-layer differential capacity (C_1) as a function of electrode charge density (σ) was estimated with curve fitting. Figure 1 shows the results of this treatment for Hg/(H_2O+CH_3OH) solution interface. In Figure 2 the corresponding mixed-adsorption isotherm curve is plotted as example, it is seen that the monolayer at Hg electrode in (H_2O+CH_3OH) solution is almost fully occupied by methanol molecules.
The model proposed in previous paper was applied to metal/(mixed-solvents) solution system. According to this model, the solvation monolayer at the charged metal surface was formed by competitive adsorption of composed solvent molecules, and the dipole orientation of every solvent molecules was considered to be present in three probable states, namely, A(r)-negative end towards the metal, B(r)-positive end towards the metal, and C(r)-the dipole vector oriented at an angle Ψ(r) to the direction of electric field. Assuming the dipole orientation distribution for this adsorption layer obeys Bragg-Williams approximation and three distinctive oriented states may be converted to each other, then the mixed-adsorption isotherm could be derived by using the statistical mechanical method together with the thermodynamic equilibrium conditions.
Using the equilibrium relations mentioned above and the expression for potential drop acrossed the monolayer regions, the inner-layer differential capacity (C_1) as a function of electrode charge density (σ) was estimated with curve fitting. Figure 1 shows the results of this treatment for Hg/(H_2O+CH_3OH) solution interface. In Figure 2 the corresponding mixed-adsorption isotherm curve is plotted as example, it is seen that the monolayer at Hg electrode in (H_2O+CH_3OH) solution is almost fully occupied by methanol molecules.
1991, 7(04): 449-455
doi: 10.3866/PKU.WHXB19910414
Abstract:
In this paper, it is demonstrated that |E(k)E(h-k)| is a structure invari ant. On the basis of this knowledge, three models, which can be used to estimate the value of |E(k)E(h-k)| from normalized structure amplitudes |E|, are proposed. In particular, |E(k)E(h-k)|_(QE), which is deduced from the second neighborhood principle of quartet structure invariants, is an ideal estimation of |E(k)E(h-k)| with known phase lacks. It is expected that |E(k)E(h-k)|_(QE) will improve the function of super-solution phase equation in systematical trial and error method and increase the accuracy of the phase values to be determined.
In this paper, it is demonstrated that |E(k)E(h-k)| is a structure invari ant. On the basis of this knowledge, three models, which can be used to estimate the value of |E(k)E(h-k)| from normalized structure amplitudes |E|, are proposed. In particular, |E(k)E(h-k)|_(QE), which is deduced from the second neighborhood principle of quartet structure invariants, is an ideal estimation of |E(k)E(h-k)| with known phase lacks. It is expected that |E(k)E(h-k)|_(QE) will improve the function of super-solution phase equation in systematical trial and error method and increase the accuracy of the phase values to be determined.
1991, 7(04): 456-461
doi: 10.3866/PKU.WHXB19910415
Abstract:
The kinetics of formation reaction of Copper(Ⅱ) with para-substituted tetraphenylporphyrin H_2(p-X)TPP (X=NO_2,Cl,H, CH_3,OCH_3) in dimethyl sulfoxide solution and the catalytic effect of Cadmium(Ⅱ) ion have been studied on Shimadru UV-240 spectrophotometer. The mechanisms were proposed and the effect of Hg(Ⅱ), Pb(Ⅱ) on this reaction was investigated. od LFER (linear free energy relationahips) between reaction rate constant/equilibrium constant with the Hammett subtituent constant σ have been ob served in certain cases.
The kinetics of formation reaction of Copper(Ⅱ) with para-substituted tetraphenylporphyrin H_2(p-X)TPP (X=NO_2,Cl,H, CH_3,OCH_3) in dimethyl sulfoxide solution and the catalytic effect of Cadmium(Ⅱ) ion have been studied on Shimadru UV-240 spectrophotometer. The mechanisms were proposed and the effect of Hg(Ⅱ), Pb(Ⅱ) on this reaction was investigated. od LFER (linear free energy relationahips) between reaction rate constant/equilibrium constant with the Hammett subtituent constant σ have been ob served in certain cases.
1991, 7(04): 462-466
doi: 10.3866/PKU.WHXB19910416
Abstract:
On the basis of the analysis of various construction methods of the hybrid orbitals, the conept of the extended basis hybrid orbital has been proposed for the hybrid orbital containing the atomic orbitals of nonvalent shell. Taking the bound conditions into account, we have derived the analytical form of the extended basis hybrid orbital with equivalent characters by using the principle of the maximum overlap. It is found that the hybrid character of one atomic orbital belonging to the central atom depends on its degree of overlap with the ligand orbitals. Some applications of this method have been given.
On the basis of the analysis of various construction methods of the hybrid orbitals, the conept of the extended basis hybrid orbital has been proposed for the hybrid orbital containing the atomic orbitals of nonvalent shell. Taking the bound conditions into account, we have derived the analytical form of the extended basis hybrid orbital with equivalent characters by using the principle of the maximum overlap. It is found that the hybrid character of one atomic orbital belonging to the central atom depends on its degree of overlap with the ligand orbitals. Some applications of this method have been given.
1991, 7(04): 467-470
doi: 10.3866/PKU.WHXB19910417
Abstract:
By utilizing the formation constants of Ni(Ⅱ)-Glycine binary complex compounds and the corresponding heats of formation from literature as well as the formation constants of Ni(Ⅱ)-Oxalate binary complex compounds and the corresponding heats of formation incorporating with the formation constants of Ni(Ⅱ)-Oxalate-Glycine competitive ternary complex compounds determined in our laboratory, the heats of formation of Ni(Ⅱ)-Oxalate-Glycine competitive ternary complex compounds have been determined at 25 ℃, I=0.1 mol·dm~(-3) (KNO_3) in aqueous solution by means of RD-1 model automatic conduction calorimeter. The results obtained are:
ΔH_(AB)~M=-14.3±2.0 kJ·mol~(-1)
ΔH_(A2B)~M=-27.0±2.0 kJ·mol~(-1)
ΔH_(AB2)~M=-40.2±2.0 kJ·mol~(-1)
By utilizing the formation constants of Ni(Ⅱ)-Glycine binary complex compounds and the corresponding heats of formation from literature as well as the formation constants of Ni(Ⅱ)-Oxalate binary complex compounds and the corresponding heats of formation incorporating with the formation constants of Ni(Ⅱ)-Oxalate-Glycine competitive ternary complex compounds determined in our laboratory, the heats of formation of Ni(Ⅱ)-Oxalate-Glycine competitive ternary complex compounds have been determined at 25 ℃, I=0.1 mol·dm~(-3) (KNO_3) in aqueous solution by means of RD-1 model automatic conduction calorimeter. The results obtained are:
ΔH_(AB)~M=-14.3±2.0 kJ·mol~(-1)
ΔH_(A2B)~M=-27.0±2.0 kJ·mol~(-1)
ΔH_(AB2)~M=-40.2±2.0 kJ·mol~(-1)
1991, 7(04): 471-474
doi: 10.3866/PKU.WHXB19910418
Abstract:
In this paper, we have determined the multiplication rate constanis (k) of Shigella flexneri and E. coli. at different temperatures and in different culture media by means of a microcalorimeter. From these results a linear equation as k~(1/2)=a+bT can be established for the bacterial growth. The corresponding linear equation for S. flexneri is k~(1/2)=-1.2823+0.0047122 T(r=0.971), so its eritica lgrowth temperature T_0 is equal to 272.1 K. The linear equation for E coli is k~(1/2)=-1.6390+0.005948 T (r=0.994), T_0=275.5 K. The experimental results indicate that the critial growth temperature of E. coli. is nearly a constant (T_0=273.9 K) in different culture media, which is very informative for the study on microorganism growth.
In this paper, we have determined the multiplication rate constanis (k) of Shigella flexneri and E. coli. at different temperatures and in different culture media by means of a microcalorimeter. From these results a linear equation as k~(1/2)=a+bT can be established for the bacterial growth. The corresponding linear equation for S. flexneri is k~(1/2)=-1.2823+0.0047122 T(r=0.971), so its eritica lgrowth temperature T_0 is equal to 272.1 K. The linear equation for E coli is k~(1/2)=-1.6390+0.005948 T (r=0.994), T_0=275.5 K. The experimental results indicate that the critial growth temperature of E. coli. is nearly a constant (T_0=273.9 K) in different culture media, which is very informative for the study on microorganism growth.
1991, 7(04): 475-479
doi: 10.3866/PKU.WHXB19910419
Abstract:
The thermodynamic properties of HCl-NaCl-d-Glueose-H_2O system was studied by emf measurement without liquid junction.
Pt, H_2(1.013×10~5 Pa)|Hel(m), d-Glucose(x), H_2O(1-x)| Agel-Ag (A) Pt, H_2(1.013×10~5Pa)|HCl(m_A), NaCl(m_B), d-Glucose(x), H_2O(1-x)|AgCl-Ag (B) at the mass percentage of d-Glucose x=5%, 15% and 20% in the mixed solution, from 5 to 45 ℃, for cell (B) at constant total ionic strength I=1.00 mol·kg~(-1). The standard electrode potential of Ag-AgCI in the mixed solution have been determined from cell (A). The activity coefficients of HCl, γ_A, in the mixed solution system have been determined from cell (B). The results show that the activity coefficients of HCl in HCl-NaCl solutions still obeye Harned Rule. The standard transfer Gibbs free energies of HCl have calculated. The primary, secondary and total medium effect of HCl have been calculated.
The thermodynamic properties of HCl-NaCl-d-Glueose-H_2O system was studied by emf measurement without liquid junction.
Pt, H_2(1.013×10~5 Pa)|Hel(m), d-Glucose(x), H_2O(1-x)| Agel-Ag (A) Pt, H_2(1.013×10~5Pa)|HCl(m_A), NaCl(m_B), d-Glucose(x), H_2O(1-x)|AgCl-Ag (B) at the mass percentage of d-Glucose x=5%, 15% and 20% in the mixed solution, from 5 to 45 ℃, for cell (B) at constant total ionic strength I=1.00 mol·kg~(-1). The standard electrode potential of Ag-AgCI in the mixed solution have been determined from cell (A). The activity coefficients of HCl, γ_A, in the mixed solution system have been determined from cell (B). The results show that the activity coefficients of HCl in HCl-NaCl solutions still obeye Harned Rule. The standard transfer Gibbs free energies of HCl have calculated. The primary, secondary and total medium effect of HCl have been calculated.
1991, 7(04): 480-484
doi: 10.3866/PKU.WHXB19910420
Abstract:
The gas-liquid chromatographic method was used to measure the activity coefficients at infinite dilution (γ_1~∞) of some nonelectrolyte solutes in salt containing solutions of propylene carbonate at 333.2 K. For examining the relationship between lgγ_1~∞ and salt concentrations, the salt effect coefficients of solutes were calculated, and the interactions of solute with salt were disscused. Furthermore, the equilibrium constant of complex interaction between chloroform with anions has been obtained.
The gas-liquid chromatographic method was used to measure the activity coefficients at infinite dilution (γ_1~∞) of some nonelectrolyte solutes in salt containing solutions of propylene carbonate at 333.2 K. For examining the relationship between lgγ_1~∞ and salt concentrations, the salt effect coefficients of solutes were calculated, and the interactions of solute with salt were disscused. Furthermore, the equilibrium constant of complex interaction between chloroform with anions has been obtained.
1991, 7(04): 485-489
doi: 10.3866/PKU.WHXB19910421
Abstract:
The results of kinetic studies of regeneration for weak basic anion exchanger in NO_3~-, Cl~- and SO_4~(2-) forms are presented. A mathematical model of shell-progressive mechanism with changing bulk solution concentration and exchanger volume in ion exchange has been used to interpret the regeneration process, and the effective diffusion coefficients have been obtained.
The results of kinetic studies of regeneration for weak basic anion exchanger in NO_3~-, Cl~- and SO_4~(2-) forms are presented. A mathematical model of shell-progressive mechanism with changing bulk solution concentration and exchanger volume in ion exchange has been used to interpret the regeneration process, and the effective diffusion coefficients have been obtained.
1991, 7(04): 490-494
doi: 10.3866/PKU.WHXB19910422
Abstract:
Study on thermokinetic properties of the reaction between laccase and hydrogen peroxide by microcalorimetry has been carried out. The rate constant of the reaction is k_1=4.15×10~(-4) s~(-1). The reoxidation of the product of the reaction of laccase with hydroquinone by hydrogen peroxide obeys Michaelis-Menten's mechanism. The Michael constant K_m equals 0.0392M.
Study on thermokinetic properties of the reaction between laccase and hydrogen peroxide by microcalorimetry has been carried out. The rate constant of the reaction is k_1=4.15×10~(-4) s~(-1). The reoxidation of the product of the reaction of laccase with hydroquinone by hydrogen peroxide obeys Michaelis-Menten's mechanism. The Michael constant K_m equals 0.0392M.
1991, 7(04): 495-498
doi: 10.3866/PKU.WHXB19910423
Abstract:
Infrared spectroscopy, viscosity measurement,HUGGINS equation and MCALLISTER equation characterization, and computer curve fitting were used to study the influence of various additives, including phosphoric acid, formamide, water, glycerine, n-propanol on the properties of cellulose acetate-acetone solutions.
Infrared spectroscopy, viscosity measurement,HUGGINS equation and MCALLISTER equation characterization, and computer curve fitting were used to study the influence of various additives, including phosphoric acid, formamide, water, glycerine, n-propanol on the properties of cellulose acetate-acetone solutions.
1991, 7(04): 499-507
doi: 10.3866/PKU.WHXB19910424
Abstract:
1991, 7(04): 508-512
doi: 10.3866/PKU.WHXB19910425
Abstract:
