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1986 Volume 2 Issue 6
1986, 2(06): 481-483
doi: 10.3866/PKU.WHXB19860601
Abstract:
Using the mierocalorimetric method the fundamental growth thermograms of Eschericher Coli, Staphylococcus acereus, Sal. Typhosa and Sal. Chaleraeuis have been determined.These perfect thermogram curves reflect the changes of bacterial growth patterns(as the lag phase of growth,exponential growth,stationary phase and the end phase of growth). In these experiments, very highly characteristic and reproducible growth patterns are observed under same condition, therefore we can use these thermograms as “finger print” to identification the bacterials. On the other hand, these thermograms curves contain ample imformation, which are very significant for the studies on microorganism metabolism, bio-thermokinetic and clinical fields.
Using the mierocalorimetric method the fundamental growth thermograms of Eschericher Coli, Staphylococcus acereus, Sal. Typhosa and Sal. Chaleraeuis have been determined.These perfect thermogram curves reflect the changes of bacterial growth patterns(as the lag phase of growth,exponential growth,stationary phase and the end phase of growth). In these experiments, very highly characteristic and reproducible growth patterns are observed under same condition, therefore we can use these thermograms as “finger print” to identification the bacterials. On the other hand, these thermograms curves contain ample imformation, which are very significant for the studies on microorganism metabolism, bio-thermokinetic and clinical fields.
1986, 2(06): 484-492
doi: 10.3866/PKU.WHXB19860602
Abstract:
The crystal structure of 1,3—dimethyl-6-azathymine and its four photocycloadducts of CH_2CH-Z(Z=CN, COCH_3) were determined by X-Ray diffraction. The main crystallographic data are listed in Tabie 1. The absolute configurations of the compounds(Ⅱ) and (Ⅳ) were not determined.
The molecular structure of 1,3-dimethy-6-azathymine is shown in Fig.1. Its six-membered ring is roughly planar. The C-N single bond lengths which are nearly equivalent in the six-membered ring are shorter than that in the photocycloadducts (see ...
The crystal structure of 1,3—dimethyl-6-azathymine and its four photocycloadducts of CH_2CH-Z(Z=CN, COCH_3) were determined by X-Ray diffraction. The main crystallographic data are listed in Tabie 1. The absolute configurations of the compounds(Ⅱ) and (Ⅳ) were not determined.
The molecular structure of 1,3-dimethy-6-azathymine is shown in Fig.1. Its six-membered ring is roughly planar. The C-N single bond lengths which are nearly equivalent in the six-membered ring are shorter than that in the photocycloadducts (see ...
1986, 2(06): 493-498
doi: 10.3866/PKU.WHXB19860603
Abstract:
The complexation of some Coumarin derivatives(C_(311), C_(47), C_(102), C_(120) and C_4) With β-CyD in aqueous solution has been examined by means of steady-state and time resolved fluorescence methods. It is observed that the fluorescence peaks, relative intensities and lifetimes of the guest molecules in aqueous solution of β- CyD reveal hypsoehromic shift, enhancement and increment respectively relative to those of guest molecules in aqueous solution. The results indicate that the CNDs complex with β-CyD to a certain extent. The measured complexation constants for CND—β-Cye systems decrease in the order of K_311 K_47 K_102 K_120 K_4. These facts reflect that the hydrophobic property of guest molecule and the matching size between the guest molecule and β-CyD are important factors affecting their complexation.
The complexation of some Coumarin derivatives(C_(311), C_(47), C_(102), C_(120) and C_4) With β-CyD in aqueous solution has been examined by means of steady-state and time resolved fluorescence methods. It is observed that the fluorescence peaks, relative intensities and lifetimes of the guest molecules in aqueous solution of β- CyD reveal hypsoehromic shift, enhancement and increment respectively relative to those of guest molecules in aqueous solution. The results indicate that the CNDs complex with β-CyD to a certain extent. The measured complexation constants for CND—β-Cye systems decrease in the order of K_311 K_47 K_102 K_120 K_4. These facts reflect that the hydrophobic property of guest molecule and the matching size between the guest molecule and β-CyD are important factors affecting their complexation.
1986, 2(06): 499-504
doi: 10.3866/PKU.WHXB19860604
Abstract:
N,N-dialkyl substituted alkyl amide has been shown as the extractant for the extraction and separation of actinides in a Purex-type flowsheet since its synthetizing is cheap enough.It exhibits a similar behavior as tri-n-butyl phosphate (TBP) but it has better decontamination of uramium from some fission products, better uranium-thorium separation, higher stability and under es to lessdeterious degradation products than TBP~[1-3].
The kinetics and mechanism of energy transfer in TBP-DPBA system have been studied and two-fold protective effect on excited TBP has been found. By using the principle of steady state, the energy transfer equation of the first kind of excited TBP is derived as follows:
....
N,N-dialkyl substituted alkyl amide has been shown as the extractant for the extraction and separation of actinides in a Purex-type flowsheet since its synthetizing is cheap enough.It exhibits a similar behavior as tri-n-butyl phosphate (TBP) but it has better decontamination of uramium from some fission products, better uranium-thorium separation, higher stability and under es to lessdeterious degradation products than TBP~[1-3].
The kinetics and mechanism of energy transfer in TBP-DPBA system have been studied and two-fold protective effect on excited TBP has been found. By using the principle of steady state, the energy transfer equation of the first kind of excited TBP is derived as follows:
....
1986, 2(06): 505-511
doi: 10.3866/PKU.WHXB19860605
Abstract:
Based on our previous work, the rule of the ordering of the elements in A matrix has been further studied from the faetorization of G matrix and vibrational frequencies. The Freeman's method for the ordering of λ_i was discussed, and the calculations of some typical examples show that this method is not Valid in general.
Based on our previous work, the rule of the ordering of the elements in A matrix has been further studied from the faetorization of G matrix and vibrational frequencies. The Freeman's method for the ordering of λ_i was discussed, and the calculations of some typical examples show that this method is not Valid in general.
1986, 2(06): 512-518
doi: 10.3866/PKU.WHXB19860606
Abstract:
A simplified MO treatment has been proposed for the cluster compounds containing both bridging and terminal ligands. The terminal ligands of a considered cluster can be treated as fragment, if only the electronic structures of the skeleton are interested in We chose a pars of the fragment MO's in the terminal ligands which are calculated beforhand as the valence orbitals of these fragments and retain a common set of skeleton atoms which is treated as in standard CNDO. The largest advantage of this approximation is in the reduction of the number of electrons and basis functions, and hance the reduction of computer time. The detailed description of the formalism has been presented and the procedure of the calculation has been programed and performed on a PDP-11-70 computer.
A simplified MO treatment has been proposed for the cluster compounds containing both bridging and terminal ligands. The terminal ligands of a considered cluster can be treated as fragment, if only the electronic structures of the skeleton are interested in We chose a pars of the fragment MO's in the terminal ligands which are calculated beforhand as the valence orbitals of these fragments and retain a common set of skeleton atoms which is treated as in standard CNDO. The largest advantage of this approximation is in the reduction of the number of electrons and basis functions, and hance the reduction of computer time. The detailed description of the formalism has been presented and the procedure of the calculation has been programed and performed on a PDP-11-70 computer.
1986, 2(06): 519-524
doi: 10.3866/PKU.WHXB19860607
Abstract:
Recently, the models of active phases (or sites) of copper-based oxychlorination (OC) catalyst have been proposed~[4,6,9]. Unfortunately, up to present how the active component dispersing onto a carrrier has not been studied in detail yet, and its real chemical composition is not unanimous either. In previous paper~[7] we proposed some ideas on that the composition, structure and activity of catalyst vary with the diffrent atmospheres. Here we will discuss them in another way and provide more experimental evidences.
1. DISPERSING OF ACTIVE COMPONENT
Quantitative XRD phase analysis indicated that until the CuCl_2 content to 0.13g/gγ-Al_2O_3 (surface area of the carrier is about 170 m~2g~(-1)) there are no peaks of crystalline CuCl_2 in the XRD pattern and the pattern is similar to that of the carrier. Amounts of crystalline CuCl_2 increase linearly with the raise of CuCl_2 content in the higher Cu content catalysts and the crystalline phase line does not pass through the origin. This result shows that the active component does not form crystallite in the lower Cu content catalyst. It must disperse onto surface of the carrier and the utmost dispersion capacity (threshold) on such carrier is about 0.13g/gγ-Al_2O_3.
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1986, 2(06): 525-532
doi: 10.3866/PKU.WHXB19860608
Abstract:
This paper presents an experimental study on the electrochemical behavior of 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) at hanging mercury drop electrode in aqueous solution.
DTNB reduction processes have seen established by means of electrolytic reduction preparation, cyclic voltammetry, UV spectroscopy, IR-spectroscopy and ESR as well as electrochemical methods. It is proved that the disulfide bond (-S-S-) of DTNB is reduced to thiol group at the potential of the reduction wave. It is also confirmed that the nitro group of DTNB is liable to be reduced to amino group during electrochemical reduction. Hence, the final reduction product of DTNB is 5-thio-2-aminobenzoic acid. The carboxyl of DTNB is not likely to be reduced in electrochemical reduction. It has been suggested that DTNB is reduced according to ECE mechanism. The final product of DTNB is oxidizable in reverse cycllic scan. Experimental demonstrations and theoretical analysis of voltammogram giye the following mechanism:
...
This paper presents an experimental study on the electrochemical behavior of 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) at hanging mercury drop electrode in aqueous solution.
DTNB reduction processes have seen established by means of electrolytic reduction preparation, cyclic voltammetry, UV spectroscopy, IR-spectroscopy and ESR as well as electrochemical methods. It is proved that the disulfide bond (-S-S-) of DTNB is reduced to thiol group at the potential of the reduction wave. It is also confirmed that the nitro group of DTNB is liable to be reduced to amino group during electrochemical reduction. Hence, the final reduction product of DTNB is 5-thio-2-aminobenzoic acid. The carboxyl of DTNB is not likely to be reduced in electrochemical reduction. It has been suggested that DTNB is reduced according to ECE mechanism. The final product of DTNB is oxidizable in reverse cycllic scan. Experimental demonstrations and theoretical analysis of voltammogram giye the following mechanism:
...
1986, 2(06): 533-540
doi: 10.3866/PKU.WHXB19860609
Abstract:
The title crystal is yellow in collour,belonging to the monoolinic system.The space group is P_(2_1)/n with following unit cell parameters: a=0.8253(5), b=2.1018(10), c=2.1531(17) nm; β=90.89(6)(°), V=3.734 (7) nm, Z=4. D_calc=1.934 gcm~(-3).
The crystal structure was solved by the direct method(MULTAN-82)and refined by full-matrix least-squares to a final conventional R factor of 0.061. The results reveal that the crystal structure consists of neutral trinuclear Mo cluster molecules, in which three independent Mo atoms form an equilateral triangle with an average side length of 0.2631 nm, corresponding to a Mo-Mo single bond. On one side of the triangle one μ_3-S atom binds the three Mo atoms together to form a monocapped trinuclear cluster. In addition, three S_2 radicals acting as μ_2 bridges are located between each two Mo atoms. Each Mo atom is also coordinated by two terminal S atoms of [S_2P(OEt)_2]~- radical so as to complete a distored penta nal bipyramid configuration.
The title crystal is yellow in collour,belonging to the monoolinic system.The space group is P_(2_1)/n with following unit cell parameters: a=0.8253(5), b=2.1018(10), c=2.1531(17) nm; β=90.89(6)(°), V=3.734 (7) nm, Z=4. D_calc=1.934 gcm~(-3).
The crystal structure was solved by the direct method(MULTAN-82)and refined by full-matrix least-squares to a final conventional R factor of 0.061. The results reveal that the crystal structure consists of neutral trinuclear Mo cluster molecules, in which three independent Mo atoms form an equilateral triangle with an average side length of 0.2631 nm, corresponding to a Mo-Mo single bond. On one side of the triangle one μ_3-S atom binds the three Mo atoms together to form a monocapped trinuclear cluster. In addition, three S_2 radicals acting as μ_2 bridges are located between each two Mo atoms. Each Mo atom is also coordinated by two terminal S atoms of [S_2P(OEt)_2]~- radical so as to complete a distored penta nal bipyramid configuration.
1986, 2(06): 541-548
doi: 10.3866/PKU.WHXB19860610
Abstract:
The electronic structures of the porphin and its dimer have been calculated by EHMO.From the differential charge distribution in the porphin dimer it has been shown that the porphin molecule belongs to the amphoteric electron donor-aceeptor in its dimer, having steady donor centers and acceptor centers. The system has minimum energy at the orientation angle ψ=45°. 4-fold barriers should be overcome when two monomers rotate each other. The barrier is ～0.09 eV. The degenerate perturbation theory has been expanded to deal with the dimer system, and according to this result the energy level corespondence between the monomer and the dimer has been explained quantitatively. It has been shown that the cause of the interaction is the charge transfer between the donor center and the acceptor center in the dimer.
The model for calculation is shown in Fig.1. The frontier orbitals and those nearby them are all π ones (ref. Table 1), and the difference between the π-π interaction energy and the total energy is less than 10% of the total one. Thereby, we only calculate the π-π interaction for simplicity.
...
The electronic structures of the porphin and its dimer have been calculated by EHMO.From the differential charge distribution in the porphin dimer it has been shown that the porphin molecule belongs to the amphoteric electron donor-aceeptor in its dimer, having steady donor centers and acceptor centers. The system has minimum energy at the orientation angle ψ=45°. 4-fold barriers should be overcome when two monomers rotate each other. The barrier is ～0.09 eV. The degenerate perturbation theory has been expanded to deal with the dimer system, and according to this result the energy level corespondence between the monomer and the dimer has been explained quantitatively. It has been shown that the cause of the interaction is the charge transfer between the donor center and the acceptor center in the dimer.
The model for calculation is shown in Fig.1. The frontier orbitals and those nearby them are all π ones (ref. Table 1), and the difference between the π-π interaction energy and the total energy is less than 10% of the total one. Thereby, we only calculate the π-π interaction for simplicity.
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1986, 2(06): 549-553
doi: 10.3866/PKU.WHXB19860611
Abstract:
In 0.2 mol L~(-1)acetate buffer Solution, at pH 4.2—4.5, carminic acid exhibits a reversible adsorptive wave in single-sweep polarogram. The electrode reaction is
(H_2L~(-))_(ads)+2H~++2e<=>(H_2L′~-)_(ads)
H_2L~- and H_2L′~(-) are the anthraqluinone and dihydroanthraquinone ions of carminic acid respectively.
On the surface of mercury electrode,the adsorption of carminic acid obeys Frumkin adsorption isotherm The adsorption coefficient(β=7.0×10~6), the interaction factor(v=-0.92), the amount of saturated adsorption (Γ_s=1.39×10~(-10) mol cm~(-2) and t...
In 0.2 mol L~(-1)acetate buffer Solution, at pH 4.2—4.5, carminic acid exhibits a reversible adsorptive wave in single-sweep polarogram. The electrode reaction is
(H_2L~(-))_(ads)+2H~++2e<=>(H_2L′~-)_(ads)
H_2L~- and H_2L′~(-) are the anthraqluinone and dihydroanthraquinone ions of carminic acid respectively.
On the surface of mercury electrode,the adsorption of carminic acid obeys Frumkin adsorption isotherm The adsorption coefficient(β=7.0×10~6), the interaction factor(v=-0.92), the amount of saturated adsorption (Γ_s=1.39×10~(-10) mol cm~(-2) and t...
1986, 2(06): 554-559
doi: 10.3866/PKU.WHXB19860612
Abstract:
The cathodic current-potential curves of CdTe electrodeposition were measused using a rotating disc electrode. It was observed that there was a od linear relation between the square root of rotating rates and the electrodeposition currents At various rotating rates,the ratio of current at -0.25 V to that at -0.50 V (vs. SCE) was close to 2/3.
The X-ray diffraction analysis, XPS and AES showed that CdTe could be electrodepsited at a potential more positive than that for Cd electrodeposition.
Based on these resul...
The cathodic current-potential curves of CdTe electrodeposition were measused using a rotating disc electrode. It was observed that there was a od linear relation between the square root of rotating rates and the electrodeposition currents At various rotating rates,the ratio of current at -0.25 V to that at -0.50 V (vs. SCE) was close to 2/3.
The X-ray diffraction analysis, XPS and AES showed that CdTe could be electrodepsited at a potential more positive than that for Cd electrodeposition.
Based on these resul...
1986, 2(06): 560-568
doi: 10.3866/PKU.WHXB19860613
Abstract:
A simple and accurate analytic representation of square-well potential hard sphere perturbation theory is derived based upon the Zwanzig perturbation method. The higher-order perturbation terms are obtained by using the Barker-Henderson approximation. A new form of radial distribution function g(R)=1/ηgj(η/(1-η))~j is proposed and applied. The theory is tested by calculating thermodynamic properies with the four-term truncated form of the (η/(1-η)) expansions and compared with available Monte Carlo and Molecular Dynamics computer simulation calculations. The results are in od agreement.
A simple and accurate analytic representation of square-well potential hard sphere perturbation theory is derived based upon the Zwanzig perturbation method. The higher-order perturbation terms are obtained by using the Barker-Henderson approximation. A new form of radial distribution function g(R)=1/ηgj(η/(1-η))~j is proposed and applied. The theory is tested by calculating thermodynamic properies with the four-term truncated form of the (η/(1-η)) expansions and compared with available Monte Carlo and Molecular Dynamics computer simulation calculations. The results are in od agreement.
1986, 2(06): 569-572
doi: 10.3866/PKU.WHXB19860614
Abstract:
The state of ZnO/γ-Al_2O_3 samples was observed by transmission electron microscopy. The crystalline substances in the samples were identified by electron diffraction experiment. The main view points mentioned in the previous paper[1] were demonstrated intuitively.
The reaction between ZnO and γ-Al_2O_3 can occur easily.The lattice constant of the formed Zn_xA1_2O_(3+x) is slightly larger than that of γ-Al_2O_3. It can be observed by THM that when ZnO content is higher than a certain value, crystalline ZnO begins to appear. The higher the temperature of calcination, the larger the value.
...
The state of ZnO/γ-Al_2O_3 samples was observed by transmission electron microscopy. The crystalline substances in the samples were identified by electron diffraction experiment. The main view points mentioned in the previous paper[1] were demonstrated intuitively.
The reaction between ZnO and γ-Al_2O_3 can occur easily.The lattice constant of the formed Zn_xA1_2O_(3+x) is slightly larger than that of γ-Al_2O_3. It can be observed by THM that when ZnO content is higher than a certain value, crystalline ZnO begins to appear. The higher the temperature of calcination, the larger the value.
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1986, 2(06): 573-575
doi: 10.3866/PKU.WHXB19860615
Abstract:
The vibrational relaxation rates of PbS~*A(0~+) state in Ar and S_2 have been studied by laser-induced fluorescence technique. The vibrational relaxation rate of PbS~*A(0~+) in S_2 is two orders of magnitude larger than in Ar. Formation of unstable intermediate PbS_3 may be responsible for the fast relaxation. The energy transfer process between A(0~+)(V'=19) and B(1)(V'=6) states is also suggested.
The vibrational relaxation rates of PbS~*A(0~+) state in Ar and S_2 have been studied by laser-induced fluorescence technique. The vibrational relaxation rate of PbS~*A(0~+) in S_2 is two orders of magnitude larger than in Ar. Formation of unstable intermediate PbS_3 may be responsible for the fast relaxation. The energy transfer process between A(0~+)(V'=19) and B(1)(V'=6) states is also suggested.
