Following the principle of elastic floating compensation, this paper presents a new metal elastic ring for load equilibration and vibration reduction in 3-ring-gear reducer, and design and fabrivcation of a metal elas...Following the principle of elastic floating compensation, this paper presents a new metal elastic ring for load equilibration and vibration reduction in 3-ring-gear reducer, and design and fabrivcation of a metal elastic ring for SCH 3-ring-gear reducer. Comparison tests run with 3-ring-gear reducers without or with the metal elastic ring show satisfactory load equilibration and vibration reduction can be achieved with the metal elastic ring, and the metal elastic ring is a good solution for the problem of unequilibrated load and excessive vibration from which 3-ring-gear reducers suffered long.- This will further the improvement of design and application of 3-ring-gear reducers in both theory and practice.展开更多
Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 ...Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 GPa. The results shows (1) during partial melting, Mg# [=Mg/(Mg+Fe)]and Cr# [=Cr/(Cr-Al)]of spinel increase with an increase in degrees of melting) (2) during subsolidus equilibration, with increasing temperatures, Mg# of spinel increases but Cr# of spinel remains almost unchanged in dunite and increases slightly in Iherzolite and harzburgite. The negative and quasi-linear Mg# -Cr# correlation of spinel represents an isotherm of total non-equilibrium. The same results have been obtained by means of mathematical modelling. It is also proved by Mg# -Cr# correlation of spinel in natural peridotites. As a result of the spinel subsolidus equilibration, only variation of Cr# of spinel is limited, and then Cr# of spinel can be used to estimate the relative degree of melting undergone by host rocks. The bigger Cr# of spinel is, the higher the degree of melting will be. By contrast, during crystallization magma, Mg# and Cr# of spinel decrease with decreasing temperatures. Likewise, Cr# of spinel in basalts may be used to indicate the feature of Cr2O3/Al2O3 of magma, and the compositional zoning of spinel may be used to study the evolution of magma (cooling rate and contamination).展开更多
About φ45 mm LiAlO2 single crystal was grown by Czochralski (Cz) technique. However, the full-width at half-maximum (FWHM) value was high to 116.9 arcsec. After three vapor transport equilibration (VTE) process...About φ45 mm LiAlO2 single crystal was grown by Czochralski (Cz) technique. However, the full-width at half-maximum (FWHM) value was high to 116.9 arcsec. After three vapor transport equilibration (VTE) processes, we can obtain high-quality LiAlO2 slice with the FWHM value of 44.2 arcsec. ZnO films were fabricated on as-grown slices and after-VTE ones by pulsed laser deposition (PLD). It was found that ZnO films on the two slices have similar crystallinity, optical transmittance and optical band gap at room temperature. These results not only show that LAO substrate is suitable for ZnO growth, but also prove that the crystal quality of LAO substrate slightly affects the structural and optical properties of ZnO film.展开更多
Bis(imino)pyridyl Fe(Ⅱ) complexes are important catalysts in ethylene oligomerization for preparingα-olefins. The metal net charge-activity relationship of bis(imino)pyridyl Fe(Ⅱ) complexes was investigated by mole...Bis(imino)pyridyl Fe(Ⅱ) complexes are important catalysts in ethylene oligomerization for preparingα-olefins. The metal net charge-activity relationship of bis(imino)pyridyl Fe(Ⅱ) complexes was investigated by molecular mechanics (MM) and net charge equilibration(QEq) method with modified Dreiding force field.It was found that metal net charge was in reverse ratio to ethylene oligomerization activity.Electron-donor substituents with less steric hindrance to the central metal were favorable to Fe complex act...展开更多
Large-sized (~2 inch, 50.8 mm) γ-LiAlO2 single crystal has been grown by conventional Czochralski (Cz) method, but the crystal has a milky, dendriform center. The samples taken from transparent and milky parts w...Large-sized (~2 inch, 50.8 mm) γ-LiAlO2 single crystal has been grown by conventional Czochralski (Cz) method, but the crystal has a milky, dendriform center. The samples taken from transparent and milky parts were ground and examined by X-ray diffraction. All diffraction peaks could be indexed in γ-LiAlO2. The crystal quality was characterized by X-ray rocking curve. The full-width at half-maximum (FWHM) values are 116.9 and 132.0 arcsec for transparent and milky parts, respectively. The vapor transport equilibrium (VTE) technique was introduced to modify the crystal quality. After 1000℃/48 h, 1100℃/48 h, 1200℃/48 h VTE processes, the FWHM values dropped to 44.2 and 55.2 arcsec for transparent and milky part, respectively. The optical transmission of transparent part was greatly enhanced from 85% to 90%, and transmission of milky part from 75% to 80% in the range of 190~1900 nm at room temperature. When the VTE temperature was raised to 1300℃, the sample cracked and FWHM values of transparent and milky parts were increased to 55.2 and 80.9 arcsec, respectively. By combining Cz technique with VTE technique, large-sized and high quality γ-LiAlO2 crystal can be obtained.展开更多
Charge state distribution of 0.8MeV/u uranium ions after transmission through a thin carbon foil has been studied. It is observed that the charge state distribution is equilibrated after the uranium ions have passed t...Charge state distribution of 0.8MeV/u uranium ions after transmission through a thin carbon foil has been studied. It is observed that the charge state distribution is equilibrated after the uranium ions have passed through a 15μg/cm^2 carbon foil. The equilibrated average charge state is 33.72 and the charge equilibration time of uranium ions in carbon foil is less than 5.4fs.展开更多
We discuss the process of equilibrium’s attainment in an interacting many-fermions system linked to a heat reservoir, whose temperature <em>T</em> is subject to a short-time disturbance of total duration ...We discuss the process of equilibrium’s attainment in an interacting many-fermions system linked to a heat reservoir, whose temperature <em>T</em> is subject to a short-time disturbance of total duration 2<span style="white-space:nowrap;"><em>τ</em>.</span> In this time-interval, its temperature increases up to a maximum value , cooling off afterward (also gradually) to its original value T<sub><em>M</em></sub>. The process is described by a typical master equation that leads eventually to equilibration. We discuss how the equilibration process depends upon 1) the system’s fermion-number, 2) the fermion-fermion interaction’s strength <em>V</em>, 3) the disturbance duration <span style="white-space:nowrap;"><span style="white-space:nowrap;">2<span style="white-space:nowrap;"><em>τ</em></span></span></span><em></em>, and finally 4) the maximum number of equations <em>N</em> of the master equation.展开更多
Three new napelline-type C20-diterpenoid alkaloids,named aconicarmichinium A and B trifluoroacetates(1 and 2) and aconicarmichinium C chloride(3),were isolated from an aqueous extract of "fu zi",the lateral root...Three new napelline-type C20-diterpenoid alkaloids,named aconicarmichinium A and B trifluoroacetates(1 and 2) and aconicarmichinium C chloride(3),were isolated from an aqueous extract of "fu zi",the lateral roots of Aconitum carmichaelii.Their structures were elucidated by extensive spectroscopic data analysis.Compounds 1-3 represent the first examples of napelline-type C20 diterpenoid alkaloid alcohol iminiums,of which the structures were fully characterized.In addition,transformation and equilibration between the alcohol iminiums(1-3) and the aza acetals la-3a were investigated by measurements of the NMR spectra in protic and aprotic deuterium solvents including alkali pyridine-d5,along with evaporation under reduced pressure and gradual additions of TFA,AcOH,and HC1.The results demonstrated that the transformation and equilibration were solvent-,base-,and acid-dependent.Especially,in aqueous biological fluid,these C20-diterpenoid alkaloids would more likely exist as the alcohol iminiums accompanied by anion counterparts in biosystems to increase their solubility, bioavailability, transportations, and functions.The absolute configurations of 1-3 were confirmed by X-ray crystallographic analysis of 2a.展开更多
We take the contribution of all valence electrons into consideration and propose a new valence electrons equilibration method to calculate the equalized electronegativity including molecular electronegativity, group e...We take the contribution of all valence electrons into consideration and propose a new valence electrons equilibration method to calculate the equalized electronegativity including molecular electronegativity, group electronegativity, and atomic charge. The ionization potential of alkanes and mono-substituted alkanes, the chemical shift of 1H NMR, and the gas phase proton affinity of aliphatic amines, alcohols, and ethers were estimated. All the expressions have good correlations. Moreover, the Sanderson method and Bratsch method were modified on the basis of the valence electrons equilibration theory. The modified Sanderson method and modified Bratsch method are more effective than their original methods to estimate these properties.展开更多
Shale cuttings and cores recovered from the subsurface and stored for hours to decades tend to dry out and lose moisture and hydrocarbons,leading to an increase in the effective matrix permeability.Moisture loss in sh...Shale cuttings and cores recovered from the subsurface and stored for hours to decades tend to dry out and lose moisture and hydrocarbons,leading to an increase in the effective matrix permeability.Moisture loss in shale samples is a fundamental sample preservation problem which can be solved by applying a standard moisture equilibration procedure to restore lost moisture.Our aim was to investigate the relationship between permeability and variable moisture as-received,as-received moisture-equilibrated and saturated moisture-equilibrated samples.Samples were crushed to a series of particle sizes(0.6-2.0)mm and moisture equilibrated at 97% relative humidity.Results show that moisture equilibration in the samples was achieved after 72 h.The permeability of the saturated moisture-equilibrated and as-received moisture-equilibrated samples decreased exponentially with increase in moisture content.The high correlation coefficient between permeability and particle size(r = 0.96 and 0.97)for moisture-equilibrated samples compared to 0.76 for as-received samples indicates that moisture equilibration improves permeability measurements in crushed shale samples.Furthermore,permeability measurements are repeatable for moisture-equilibrated samples compared to samples that were not equilibrated(as-received).We conclude that moisture content affects permeability and moisture equilibration normalizes and improves the repeatability of permeability measurements in crushed shale.展开更多
The Henry's Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The ...The Henry's Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23℃). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry's Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.展开更多
The structure of a strip LiNbO3 waveguide clad with a planar LiNbOa waveguide is proposed to fabricate a long-period waveguide grating (LPWG). It is shown theoretically that an LPWG device based on such a special Li...The structure of a strip LiNbO3 waveguide clad with a planar LiNbOa waveguide is proposed to fabricate a long-period waveguide grating (LPWG). It is shown theoretically that an LPWG device based on such a special LiNbOa waveguide structure is of the merit of thermal stability. The methods for fabrication of planar waveguide, channel waveguide and grating are suggested and discussed. Detailed design consideration is exemplified based on a soft-proton-exchange planar waveguide clad Ti-diffused LiNbOa (Z-cut) strip waveguide.展开更多
The objective of the present study was to determine the proper sources and concentrations of soybean lecithin (phosphatidylcholine, PC) to be used as substitute for hen egg yolk in extender for preserving goat semen...The objective of the present study was to determine the proper sources and concentrations of soybean lecithin (phosphatidylcholine, PC) to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin (20% and 95% soybean phosphatidylcholine; PC20 and PC95) and three concentrations (1%, 2% and 3% v/v) of PC20 and PC95 supplemented in Tris-citric acid-fructose (TCF) extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ (equilibration). The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender (P 〈 0.05). Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders (P 〈 0.05). PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 (P 〈 0.05). It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% (v/v) is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs .展开更多
Knowledge of the soil water characteristic curve is fundamental for understanding unsaturated soils.The objective of this work was to find scanning hysteresis loops of two fine textured soils at water potentials below...Knowledge of the soil water characteristic curve is fundamental for understanding unsaturated soils.The objective of this work was to find scanning hysteresis loops of two fine textured soils at water potentials below wilting point.This was done by equilibration over NaCl solutions with water potentials of-6.6 to-18.8 MPa at 25℃.When cycled repeatedly through a series of potentials in the range noted previously both soils exhibited a hysteresis effect.The experimental differences in water content between the drying and wetting soils at the same water potential were much too large to be accounted for by failure to allow sufficient time to attain equilibrium as predicted by the exponential decay model.The wetting versus drying differences were relatively small,however,at only 4 mg g-1 or less in absolute terms and about 3% of the mean of wetting and drying,in relative terms.Hysteresis should be a consideration when modeling biological and physical soil processes at water contents below the wilting point,where small differences in water content result in large potential energy changes.展开更多
A novel reactive polyorganosiloxane containing nitro groups was first prepared by acid-catalyzed equilibration polymerization. The monomer, 3-(4-nitrophenoxy)propylmethyldichlorosilane (NPPMS), was synthesized by hydr...A novel reactive polyorganosiloxane containing nitro groups was first prepared by acid-catalyzed equilibration polymerization. The monomer, 3-(4-nitrophenoxy)propylmethyldichlorosilane (NPPMS), was synthesized by hydrosilylation reaction with dicyciopentadienylplatinum(II) chloride (Cp2PtCl2) catalyst in high yield. The synthesized polynitroorganosiloxane, which has potential application as a precursor for synthesizing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, vapor pressure osmometry (VPO) and gel permeation chromatography(GPC).展开更多
1 Introduction The stable isotopes of hydrogen and oxygen(δ2H andδ18O)are excellent tracers for studies on the natural water cycle.The isotopic signature of different water bodies
The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ...The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.展开更多
By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a part...By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a particular case of it.Some of the variables affecting equilibrium atmosphere when trace oxygen is present and optimum preparation of the gas mixtures to min- imize errors have been discussed.The reliability of some of previous equilibrium experiments under the oxygen potentials controlled by H_2O-H_2 or H_2O-H_2-inerts gas mixtures has also been criticized.展开更多
The first part of this article addresses the main premise of the Theory of Musical Equilibration. It states that in contrast to previous hypotheses, music does not directly describe emotions: instead;it evokes process...The first part of this article addresses the main premise of the Theory of Musical Equilibration. It states that in contrast to previous hypotheses, music does not directly describe emotions: instead;it evokes processes of the will which the listener identifies with. It is not until these processes are experienced that music appears to take on an emotional character. The second part of the article focuses on demonstrating the emotional nature of musical harmonies. The Basic Test and the Rocky Test are presented. These tests were designed to find correlations between chords and scenes from fairy tales as well as emotional terms. 86% of the participants correlated the musical selection to the emotion outlined by the Theory of Musical Equilibration the authors developed in this context.展开更多
Since our Department for Dialysis performs the Peritoneal Equilibration Test (PET) to monitor peritoneal dialysis adequacy, our Laboratory has been asked to collaborate on calculating clearances and transport charac...Since our Department for Dialysis performs the Peritoneal Equilibration Test (PET) to monitor peritoneal dialysis adequacy, our Laboratory has been asked to collaborate on calculating clearances and transport characteristics of patients. This collaboration is ongoing since 2003, despite the Baxter-PD Adequest software having appeared. Our aim is to emphasize the importance of the laboratory in the selection of formulas and specifically in solving the problem of determining creatinine concentration in PETs, and to recommend the cooperation between the laboratory and the dialysis department. Since creatinine determination is encumbered by recommendations for correcting elevated creatinine levels because of the influence of glucose in PETs, we compared results of dialysates determined as serum and as urine. Until now we had 86 patients on continuous ambulatory peritoneal dialysis (CAPD). Method for determining patients' creatinine remains Jaffe kinetic uncompesated although the analyzers and the corresponding reagenses were changed in the laboratory. We have achieved the complete cooperation and confidence in the result, and with the PET test performed strictly according to the protocol, increasingly better results for clearences, Kt/V and transport characteristics. All this helps with treatment planning and analyzing patients' quality of life.展开更多
基金This project is sponsored by the National Natural Science Foundationthe National Key Laboratory of Mechanical Transmission of tfe Chongqing University
文摘Following the principle of elastic floating compensation, this paper presents a new metal elastic ring for load equilibration and vibration reduction in 3-ring-gear reducer, and design and fabrivcation of a metal elastic ring for SCH 3-ring-gear reducer. Comparison tests run with 3-ring-gear reducers without or with the metal elastic ring show satisfactory load equilibration and vibration reduction can be achieved with the metal elastic ring, and the metal elastic ring is a good solution for the problem of unequilibrated load and excessive vibration from which 3-ring-gear reducers suffered long.- This will further the improvement of design and application of 3-ring-gear reducers in both theory and practice.
文摘Systematic experimental studies on partial melting and subsolidus equilibration of three reconstituted spinel-peridotites have been carried out at temperatures ranging from 1000 to 1380℃ and pressures of 1.0 and 1.5 GPa. The results shows (1) during partial melting, Mg# [=Mg/(Mg+Fe)]and Cr# [=Cr/(Cr-Al)]of spinel increase with an increase in degrees of melting) (2) during subsolidus equilibration, with increasing temperatures, Mg# of spinel increases but Cr# of spinel remains almost unchanged in dunite and increases slightly in Iherzolite and harzburgite. The negative and quasi-linear Mg# -Cr# correlation of spinel represents an isotherm of total non-equilibrium. The same results have been obtained by means of mathematical modelling. It is also proved by Mg# -Cr# correlation of spinel in natural peridotites. As a result of the spinel subsolidus equilibration, only variation of Cr# of spinel is limited, and then Cr# of spinel can be used to estimate the relative degree of melting undergone by host rocks. The bigger Cr# of spinel is, the higher the degree of melting will be. By contrast, during crystallization magma, Mg# and Cr# of spinel decrease with decreasing temperatures. Likewise, Cr# of spinel in basalts may be used to indicate the feature of Cr2O3/Al2O3 of magma, and the compositional zoning of spinel may be used to study the evolution of magma (cooling rate and contamination).
文摘About φ45 mm LiAlO2 single crystal was grown by Czochralski (Cz) technique. However, the full-width at half-maximum (FWHM) value was high to 116.9 arcsec. After three vapor transport equilibration (VTE) processes, we can obtain high-quality LiAlO2 slice with the FWHM value of 44.2 arcsec. ZnO films were fabricated on as-grown slices and after-VTE ones by pulsed laser deposition (PLD). It was found that ZnO films on the two slices have similar crystallinity, optical transmittance and optical band gap at room temperature. These results not only show that LAO substrate is suitable for ZnO growth, but also prove that the crystal quality of LAO substrate slightly affects the structural and optical properties of ZnO film.
基金supported by the National Science Foundation of China(Nos20334030,50703044 and 20734002)
文摘Bis(imino)pyridyl Fe(Ⅱ) complexes are important catalysts in ethylene oligomerization for preparingα-olefins. The metal net charge-activity relationship of bis(imino)pyridyl Fe(Ⅱ) complexes was investigated by molecular mechanics (MM) and net charge equilibration(QEq) method with modified Dreiding force field.It was found that metal net charge was in reverse ratio to ethylene oligomerization activity.Electron-donor substituents with less steric hindrance to the central metal were favorable to Fe complex act...
文摘Large-sized (~2 inch, 50.8 mm) γ-LiAlO2 single crystal has been grown by conventional Czochralski (Cz) method, but the crystal has a milky, dendriform center. The samples taken from transparent and milky parts were ground and examined by X-ray diffraction. All diffraction peaks could be indexed in γ-LiAlO2. The crystal quality was characterized by X-ray rocking curve. The full-width at half-maximum (FWHM) values are 116.9 and 132.0 arcsec for transparent and milky parts, respectively. The vapor transport equilibrium (VTE) technique was introduced to modify the crystal quality. After 1000℃/48 h, 1100℃/48 h, 1200℃/48 h VTE processes, the FWHM values dropped to 44.2 and 55.2 arcsec for transparent and milky part, respectively. The optical transmission of transparent part was greatly enhanced from 85% to 90%, and transmission of milky part from 75% to 80% in the range of 190~1900 nm at room temperature. When the VTE temperature was raised to 1300℃, the sample cracked and FWHM values of transparent and milky parts were increased to 55.2 and 80.9 arcsec, respectively. By combining Cz technique with VTE technique, large-sized and high quality γ-LiAlO2 crystal can be obtained.
基金Project supported by the National Natural Science Foundation of China (Grant No 10405025)
文摘Charge state distribution of 0.8MeV/u uranium ions after transmission through a thin carbon foil has been studied. It is observed that the charge state distribution is equilibrated after the uranium ions have passed through a 15μg/cm^2 carbon foil. The equilibrated average charge state is 33.72 and the charge equilibration time of uranium ions in carbon foil is less than 5.4fs.
文摘We discuss the process of equilibrium’s attainment in an interacting many-fermions system linked to a heat reservoir, whose temperature <em>T</em> is subject to a short-time disturbance of total duration 2<span style="white-space:nowrap;"><em>τ</em>.</span> In this time-interval, its temperature increases up to a maximum value , cooling off afterward (also gradually) to its original value T<sub><em>M</em></sub>. The process is described by a typical master equation that leads eventually to equilibration. We discuss how the equilibration process depends upon 1) the system’s fermion-number, 2) the fermion-fermion interaction’s strength <em>V</em>, 3) the disturbance duration <span style="white-space:nowrap;"><span style="white-space:nowrap;">2<span style="white-space:nowrap;"><em>τ</em></span></span></span><em></em>, and finally 4) the maximum number of equations <em>N</em> of the master equation.
基金Financial support from the National Natural Science Foundation of China (NNSFC Nos. 21132009, 30825044)the National Science and Technology Project of China (Nos. 2012ZX09301002002, 2011ZX0 9307-002-01)
文摘Three new napelline-type C20-diterpenoid alkaloids,named aconicarmichinium A and B trifluoroacetates(1 and 2) and aconicarmichinium C chloride(3),were isolated from an aqueous extract of "fu zi",the lateral roots of Aconitum carmichaelii.Their structures were elucidated by extensive spectroscopic data analysis.Compounds 1-3 represent the first examples of napelline-type C20 diterpenoid alkaloid alcohol iminiums,of which the structures were fully characterized.In addition,transformation and equilibration between the alcohol iminiums(1-3) and the aza acetals la-3a were investigated by measurements of the NMR spectra in protic and aprotic deuterium solvents including alkali pyridine-d5,along with evaporation under reduced pressure and gradual additions of TFA,AcOH,and HC1.The results demonstrated that the transformation and equilibration were solvent-,base-,and acid-dependent.Especially,in aqueous biological fluid,these C20-diterpenoid alkaloids would more likely exist as the alcohol iminiums accompanied by anion counterparts in biosystems to increase their solubility, bioavailability, transportations, and functions.The absolute configurations of 1-3 were confirmed by X-ray crystallographic analysis of 2a.
文摘We take the contribution of all valence electrons into consideration and propose a new valence electrons equilibration method to calculate the equalized electronegativity including molecular electronegativity, group electronegativity, and atomic charge. The ionization potential of alkanes and mono-substituted alkanes, the chemical shift of 1H NMR, and the gas phase proton affinity of aliphatic amines, alcohols, and ethers were estimated. All the expressions have good correlations. Moreover, the Sanderson method and Bratsch method were modified on the basis of the valence electrons equilibration theory. The modified Sanderson method and modified Bratsch method are more effective than their original methods to estimate these properties.
基金supported in part by Grants-in-Aid Fund from the American Association of Petroleum Geologists and National Association of Black Geoscientists
文摘Shale cuttings and cores recovered from the subsurface and stored for hours to decades tend to dry out and lose moisture and hydrocarbons,leading to an increase in the effective matrix permeability.Moisture loss in shale samples is a fundamental sample preservation problem which can be solved by applying a standard moisture equilibration procedure to restore lost moisture.Our aim was to investigate the relationship between permeability and variable moisture as-received,as-received moisture-equilibrated and saturated moisture-equilibrated samples.Samples were crushed to a series of particle sizes(0.6-2.0)mm and moisture equilibrated at 97% relative humidity.Results show that moisture equilibration in the samples was achieved after 72 h.The permeability of the saturated moisture-equilibrated and as-received moisture-equilibrated samples decreased exponentially with increase in moisture content.The high correlation coefficient between permeability and particle size(r = 0.96 and 0.97)for moisture-equilibrated samples compared to 0.76 for as-received samples indicates that moisture equilibration improves permeability measurements in crushed shale samples.Furthermore,permeability measurements are repeatable for moisture-equilibrated samples compared to samples that were not equilibrated(as-received).We conclude that moisture content affects permeability and moisture equilibration normalizes and improves the repeatability of permeability measurements in crushed shale.
基金Supported by the National Natural Science Foundation of China (Nos.30970522,40576058)the National Natural Science Foundation of China for Creative Research Groups (No.41121064)
文摘The Henry's Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23℃). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry's Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.
文摘The structure of a strip LiNbO3 waveguide clad with a planar LiNbOa waveguide is proposed to fabricate a long-period waveguide grating (LPWG). It is shown theoretically that an LPWG device based on such a special LiNbOa waveguide structure is of the merit of thermal stability. The methods for fabrication of planar waveguide, channel waveguide and grating are suggested and discussed. Detailed design consideration is exemplified based on a soft-proton-exchange planar waveguide clad Ti-diffused LiNbOa (Z-cut) strip waveguide.
文摘The objective of the present study was to determine the proper sources and concentrations of soybean lecithin (phosphatidylcholine, PC) to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin (20% and 95% soybean phosphatidylcholine; PC20 and PC95) and three concentrations (1%, 2% and 3% v/v) of PC20 and PC95 supplemented in Tris-citric acid-fructose (TCF) extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ (equilibration). The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender (P 〈 0.05). Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders (P 〈 0.05). PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 (P 〈 0.05). It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% (v/v) is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs .
文摘Knowledge of the soil water characteristic curve is fundamental for understanding unsaturated soils.The objective of this work was to find scanning hysteresis loops of two fine textured soils at water potentials below wilting point.This was done by equilibration over NaCl solutions with water potentials of-6.6 to-18.8 MPa at 25℃.When cycled repeatedly through a series of potentials in the range noted previously both soils exhibited a hysteresis effect.The experimental differences in water content between the drying and wetting soils at the same water potential were much too large to be accounted for by failure to allow sufficient time to attain equilibrium as predicted by the exponential decay model.The wetting versus drying differences were relatively small,however,at only 4 mg g-1 or less in absolute terms and about 3% of the mean of wetting and drying,in relative terms.Hysteresis should be a consideration when modeling biological and physical soil processes at water contents below the wilting point,where small differences in water content result in large potential energy changes.
文摘A novel reactive polyorganosiloxane containing nitro groups was first prepared by acid-catalyzed equilibration polymerization. The monomer, 3-(4-nitrophenoxy)propylmethyldichlorosilane (NPPMS), was synthesized by hydrosilylation reaction with dicyciopentadienylplatinum(II) chloride (Cp2PtCl2) catalyst in high yield. The synthesized polynitroorganosiloxane, which has potential application as a precursor for synthesizing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, vapor pressure osmometry (VPO) and gel permeation chromatography(GPC).
基金financially supported by the National Basic Research Program of China, No.2010CB428803
文摘1 Introduction The stable isotopes of hydrogen and oxygen(δ2H andδ18O)are excellent tracers for studies on the natural water cycle.The isotopic signature of different water bodies
文摘The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.
文摘By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a particular case of it.Some of the variables affecting equilibrium atmosphere when trace oxygen is present and optimum preparation of the gas mixtures to min- imize errors have been discussed.The reliability of some of previous equilibrium experiments under the oxygen potentials controlled by H_2O-H_2 or H_2O-H_2-inerts gas mixtures has also been criticized.
文摘The first part of this article addresses the main premise of the Theory of Musical Equilibration. It states that in contrast to previous hypotheses, music does not directly describe emotions: instead;it evokes processes of the will which the listener identifies with. It is not until these processes are experienced that music appears to take on an emotional character. The second part of the article focuses on demonstrating the emotional nature of musical harmonies. The Basic Test and the Rocky Test are presented. These tests were designed to find correlations between chords and scenes from fairy tales as well as emotional terms. 86% of the participants correlated the musical selection to the emotion outlined by the Theory of Musical Equilibration the authors developed in this context.
文摘Since our Department for Dialysis performs the Peritoneal Equilibration Test (PET) to monitor peritoneal dialysis adequacy, our Laboratory has been asked to collaborate on calculating clearances and transport characteristics of patients. This collaboration is ongoing since 2003, despite the Baxter-PD Adequest software having appeared. Our aim is to emphasize the importance of the laboratory in the selection of formulas and specifically in solving the problem of determining creatinine concentration in PETs, and to recommend the cooperation between the laboratory and the dialysis department. Since creatinine determination is encumbered by recommendations for correcting elevated creatinine levels because of the influence of glucose in PETs, we compared results of dialysates determined as serum and as urine. Until now we had 86 patients on continuous ambulatory peritoneal dialysis (CAPD). Method for determining patients' creatinine remains Jaffe kinetic uncompesated although the analyzers and the corresponding reagenses were changed in the laboratory. We have achieved the complete cooperation and confidence in the result, and with the PET test performed strictly according to the protocol, increasingly better results for clearences, Kt/V and transport characteristics. All this helps with treatment planning and analyzing patients' quality of life.