The properties of synthetic graphite materials, widely used in advanced fields, are determined by their structure, which is formed in the process of high-temperature (~2500<span style="white-space:normal;"...The properties of synthetic graphite materials, widely used in advanced fields, are determined by their structure, which is formed in the process of high-temperature (~2500<span style="white-space:normal;"><span style="white-space:nowrap;">°</span></span><span style="white-space:normal;"></span>C) heat treatment. The fine structure of a graphitizing carbon material based on petroleum coke containing 1.3 wt% S at various stages of graphitization was studied by X-ray diffraction analysis. Some of the samples contained the addition of dispersed Fe<sub>2</sub>O<sub>3</sub>. It is shown that the heat-treated material in the range 1200<span style="white-space:normal;"><span style="white-space:nowrap;">°</span></span><span style="white-space:normal;"></span>C - 2600<span style="white-space:normal;"><span style="white-space:nowrap;">°</span></span><span style="white-space:normal;"></span>C is heterogeneous, its component composition is determined by the processing temperature and the presence of Fe<sub>2</sub>O<sub>3</sub> additive. The observed dependence of the component composition on the heat treatment temperature suggests that the process of graphitization of the carbon material, apparently, develops through a number of metastable states.展开更多
Phosphorus(P)is an essential and limited resource.Incineration sewage sludge ash(ISSA)contains a high amount of P,which can be recovered using chemical leaching methods.However,the recovery ratio depends on the specia...Phosphorus(P)is an essential and limited resource.Incineration sewage sludge ash(ISSA)contains a high amount of P,which can be recovered using chemical leaching methods.However,the recovery ratio depends on the speciation of P and the leaching conditions.In this study,hydrochloric acid was used as a leaching agent,and the effects of the hydrochloric acid concentration,leaching time,temperature,and liquid-solid ratio on the P leaching ratio were investigated.Furthermore,the co-leaching of macro-metals Ca,Al,Fe,and Mg was analyzed.The results showed that P leached rapidly within 30 min,where the leaching rate reached more than 80%and then gradually stabilized.The leaching concentrations of Ca and Mg had a significant correlation(correlation coefficient r^(2)>0.90),and both were leached completely.Al and P had similar leaching patterns,where the leaching rates increased initially and then decreased with time at 0.2 mol/L HCl.According to X-ray diffraction analysis and Rietveld refinement,the P in ISSA was mainly present in the forms of Mg_(3)Ca_(3)(PO_(4))_(4) and AlPO_(4).When leached using 0.2 mol/L HCl at 55℃ with a liquid-to-solid ratio of 20 L/kg,the AlPO_(4) and Fe_(3)(H_(2)O)_(3)(PO_(4))_(2) in ISSA dissolved initially and then precipitated on the surface of the solid phase,thereby impeding further P leaching.展开更多
ZnO films were deposited on glass substrates by means of a direct current (DC) sputtering technique. The physical properties of the films were investigated on the basis of X-ray diffraction measurements. It was found ...ZnO films were deposited on glass substrates by means of a direct current (DC) sputtering technique. The physical properties of the films were investigated on the basis of X-ray diffraction measurements. It was found that as-deposited films show c-axis oriented crystal normal to the surface with the extension of c axis by 1.27% that is estimated from the shift of the peak in the X-ray diffraction pattern. Post-deposition annealing in air at higher than 400℃ eliminates the shift and sharpens the diffraction peak structure at the same time. The electrical resistivity continues to decrease from 500 Ω•cm down to 0.6 Ω•cm by annealing as high as 600℃.展开更多
A series of novel enantiomerically pure diols were synthesized from D-erythorbic acid in three steps, and the absolute configuration of one of them 4a has been confirmed by X-ray analysis.
The title compound, FeCl<sub>4</sub>(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>)(C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>) consists of tw...The title compound, FeCl<sub>4</sub>(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>)(C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>) consists of two [(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>) (C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>)]<sup>+</sup> organic cations and [FeCl<sub>4</sub>]<sup>-</sup> anion. The geometry of the iron ion is tetrahedral, formed by four chlorine atoms. The complex was characterized by single crystal X-ray diffraction, Fourier Transform Infrared spectroscopy, thermal analysis and UV-Visible spectroscopy. Hirshfeld surface analysis was also used for understanding the intermolecular interactions in the crystal packing. Single-crystal X-ray diffraction analysis indicates that this complex crystallizes in the monoclinic system, P2<sub>1</sub>/c space group with a = 7.598 (3) Å, b = 13.694 (4) Å, c = 17.105 (5) Å, <i>β</i><i> </i>= 97.203 (6)° V = 1765.7 (10) Å<sup>3</sup> and Z = 4. The [FeCl<sub>4</sub>]<sup>-</sup> anion and [(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>)(C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>)]<sup>+</sup> cations are linked through three-dimensional hydrogen-bonding network consisting of N-H...Cl and π-π interactions. Hirshfeld surface analysis and the related 2D fingerprint plots reveal that the complex is dominated by N-H...Cl contacts.展开更多
Trans-2,2?,4,4?-tetramethyl-6,6?-dinitro azobenzene (C16H16N4O4, Mr = 328.32) was isolated from benzene extract of the leaves of Aconitum sungpanense Hand. Mazz. as a new compound, and characterized by spectral method...Trans-2,2?,4,4?-tetramethyl-6,6?-dinitro azobenzene (C16H16N4O4, Mr = 328.32) was isolated from benzene extract of the leaves of Aconitum sungpanense Hand. Mazz. as a new compound, and characterized by spectral methods and X-ray diffraction analysis. It crystallizes in monoclinic system, space group P21/c with a = 8.544(1), b = 13.997(2), c = 7.161(1) ? ?= 112.97(1), V = 788.4(2) ?, Z = 4, Dc = 1.383 g/cm3, F(000) = 344 and ?MoKa) = 0.102 mm-1. The final R = 0.0395 and wR = 0.1140 for 1913 independent reflections with Rint = 0.0109 and 1329 observed reflections with I > 2s(I). The molecule is composed of two phenyl rings through trans N=N.展开更多
1’,4’-Trans-diol of abscisic acid was isolated from botrytis cinerea as a colorless crystal. The molecular and crystal structures have been determined by X-ray diffraction analysis. It crystallizes in orthorhombic s...1’,4’-Trans-diol of abscisic acid was isolated from botrytis cinerea as a colorless crystal. The molecular and crystal structures have been determined by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with a = 6.724(3), b = 17.559(6), c = 12.265(2) , α = β = γ = 90o, V = 1448.1(8) 3, Z = 4, Dx = 1.222 g/cm3, F(000) = 576 and μ(MoKa) = 0.087 mm-1. The final R = 0.0628 and wR = 0.1604 for 2501 independent reflections with Rint = 0.0160 and 1679 observed reflections with I >2σ(I). There are three intermolecular hydrogen bonds in a unit cell.展开更多
anhydro-2-triflyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5’-O-TBS-2’,3’-di-O-acetyl-N1-(...anhydro-2-triflyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5’-O-TBS-2’,3’-di-O-acetyl-N1-(2’’-deoxy-1",4"-anhydro-3’’,5’’-O-benzenylidene-L- lyxitol-2’’-yl)-8-bromoinosine (14). Selective removal of 5’-O-TBS-group gave the corresponding 5’-O-phosphorodianilidate 4 though phosphorylation, which was characterized by X-ray crystallographic analysis.展开更多
This paper reviews research on coprolites from India,providing the first evidence of microcoprolites from the early Miocene(Aquitanian)Khari Nadi Formation sedimentary succession,exposed about 1.5 km northeast of the ...This paper reviews research on coprolites from India,providing the first evidence of microcoprolites from the early Miocene(Aquitanian)Khari Nadi Formation sedimentary succession,exposed about 1.5 km northeast of the village of Kotada,Kachchh(Kutch)District,Gujarat State,western India.Morphometric and size comparisons(in a statistical framework)with known coprolites from the Mesozoic-Cenozoic successions of India(including those recorded herein)and globally suggest that fishes were the likely producers of the Kotada coprolites.Scanning electron microscopy confirms the presence of fish dental remains within the coprolites,while both Scanning Electron Microscopy(SEM)and Energy Dispersive X-ray Spectroscopy(EDS)reveal the phosphatic nature of the microscopic coprolite specimens(recorded herein)hinting that the producer(s)were predominantly carnivorous(ichthyophagous)in their diet.Furthermore,X-Ray Fluorescence(XRF)analysis of the host and associated lithologies allows us to deduce that the Kotada coprolites were deposited in a shallow marine environment,with possible aerial exposure of the host lithology occurring at some point after deposition.To the best of our knowledge,the present report is the first record of microscopic fish coprolites from India,as well as being the first from the Aquitanian of India and the oldest Neogene record from India.展开更多
The influence of two-stage isothermal treatment on the change in the linear dimensions of the fiber, the average sizes of the coherent scattering regions, the texture and phase composition of the polyacrylonitrile fib...The influence of two-stage isothermal treatment on the change in the linear dimensions of the fiber, the average sizes of the coherent scattering regions, the texture and phase composition of the polyacrylonitrile fiber in the process of isothermal thermal stabilization is considered by the methods of dilatometry and X-ray diffraction analysis. It is shown that preliminary short-term heat treatment at a lower temperature affects the process of structural transformations of the polyacrylonitrile fiber material and the formation of a new highly dispersed phase of the thermally stabilized fiber.展开更多
Determining the contents of F,S(total),and Cl in the studied samples of the limestone and marbles with high calcite contents was carried out by the nondestructive method of WDXRFS(Wavelength Dispersive X-ray Fluoresce...Determining the contents of F,S(total),and Cl in the studied samples of the limestone and marbles with high calcite contents was carried out by the nondestructive method of WDXRFS(Wavelength Dispersive X-ray Fluorescence Spectrometry).All measurements were performed in a vacuum condition using a WDXRF spectrometer S8 TIGER(Bruker AXS,Germany).The studied samples have wide ranges of F,S(total),and Cl contents,and high concentration of calcite(89.5%-99%).Main objective of this research is to develop WDXRF(WD X-ray fluorescence)technique for the determination of F,S(total),and Cl.The calculated values of the ILD(instrumental limit of the detection)were within the interval from 3 for S(total)to 37 for F mg/kg.The repeatability was found to be satisfactory with the relative standard deviations lower than 7%.展开更多
The evaluation of the effect of using moringa oleifera seed powder(MOSP)to partially replace cement by wt.%has been carried out.A mix parameter of 1:1.7:2.5,with designed strength of 20 kN-m^(2),and a cement content o...The evaluation of the effect of using moringa oleifera seed powder(MOSP)to partially replace cement by wt.%has been carried out.A mix parameter of 1:1.7:2.5,with designed strength of 20 kN-m^(2),and a cement content of 420 kg-m3,water-cementitious ratio of 0.5,to produce concrete specimens to which percentages of MOSP by wt.%of cement were added and cured for 90 days.Basic characteristics of the MOSP material were determined(Consistency and Setting times),and the concrete parameters workability,density,water absorption and compressive strength were also determined.The analysis of the experimental data collected on MOSP and MOSP-concrete confirmed that MOSP is substantially silicate(Quartz and Cristobalite).These have greatly to a large extent imparted on the quality of MOSP-concrete produced good quality concrete.The optimum replacement was at 0.2%wt.%of cement.展开更多
1 Results We have recently reported the Mizoroki-Heck reaction catalyzed by PdCl2 and imidazole ligands[1]. During the course of our study of palladium imidazole complex,we disclosed the synthesis of trans-Pd(Ln)2Cl2 ...1 Results We have recently reported the Mizoroki-Heck reaction catalyzed by PdCl2 and imidazole ligands[1]. During the course of our study of palladium imidazole complex,we disclosed the synthesis of trans-Pd(Ln)2Cl2 by the reaction of PdCl2 with Ln (where L1=2-phenylimidazole,L2=2-phenylimidazole) in a 1∶2 molar ratio.The single crystals of trans-Pd(L1)2Cl2·2DMF (1a) and trans-Pd(L2)2Cl2 (2a) were obtained by following slow evaporation of DMF as a solvent. The single crystal of trans-Pd(L2)2Cl2 (2b) w...展开更多
In this work,high quality uniform and dense nanostructured cobalt-doped zinc oxide(ZnO:Co)films were used as electron-transport layers in CH3NH3Pbl3-based planar heterojunction perovskite solar cells(PSCs)on a flexibl...In this work,high quality uniform and dense nanostructured cobalt-doped zinc oxide(ZnO:Co)films were used as electron-transport layers in CH3NH3Pbl3-based planar heterojunction perovskite solar cells(PSCs)on a flexible conductive substrate.Highly photo catalytically active ZnO:Co films were prepared by a low cost hydrothermal process using the aqueous solution of zinc nitrate hexahydrate,hexamethylenete-tramine and cobalt(II)nitrate hexahydrate.ZnO:Co films were deposited on indium tin oxide(ITO)covered polyethylene terephthalate(PET)flexible substrates.The growth was controlled by maintaining the autoclave temperature at 150℃for 4 h.The CH3NH3Pbl3 layer was deposited on the ZnO:Co films by spin coating.Spiro-OMeTAD was employed as a hole-transporting material.The structural,morphology and optical properties of the grown ZnO nanostructures were characterized by X-ray diffraction(XRD),field-emission scanning electron microcopy(FESEM),energy-dispersive X-ray spectrometry(EDX),ultraviolet-visible(UV-Vis)and photoelectrochemical propriety.XRD spectra showed that both ZnO and ZnO:Co nanorods had a hexagonal wurtzite structure with a strong preferred orientation along the(002)plane.The surface morphology of films was studied by FESEM and showed that both the pure and Co-doped ZnO films had hexagonal shaped nanorods.In the steady state,the ZnO electrode gave a photocurrent density of about 1.5 mA/cm2.However,the Co-doped ZnO electrode showed a photocurrent density of about 6 mA/cm^2,which is 4-fold higher than that of the ZnO electrode.Based on the above synthesized Co-doped ZnO films,the photovoltaic performance of PSCs was studied.The Co-doped ZnO layers had a significant impact on the photovoltaic conversion efficiency(PCE)of the PSCs.The latter was attributed to an efficient charge separation and transport due to the better coverage of perovskite on the nanostructured Co-doped ZnO films.As a result,the measured PCE under standard solar conditions(A M 1.5G,100 mW/cm^2)reached 7%.SCAPS-1D simulation was also performed to analyze the effect of the co-doped ZnO thin film on the corresponding solar cell performances.展开更多
Tibet, which is rich in mineral resources, is a treasure trove for geological explorers. However, prospecting work has been slow, especially in the western part, due to the precipitous terrain, changeable climate and ...Tibet, which is rich in mineral resources, is a treasure trove for geological explorers. However, prospecting work has been slow, especially in the western part, due to the precipitous terrain, changeable climate and low access. Hence, modern advanced field analytical technology and effective data processing methods play significant roles in rapid and efficient exploration in Tibet. In this paper, spectrum-area fractal modeling and portable X-ray fluorescence analysis(pXRFA) were used to identify and verify geochemical anomalies associated with Ag-Pb-Zn mineralization based on a stream-sediment dataset of 39 elements in the Dajiacuo-Xurucuo region of western Tibet. First, staged factor analysis(SFA) was used to obtain the Ag-Pb-Zn-Cd geochemical assemblage. Second, the first-factor pattern obtained using SFA was dissociated by a spectrum-area(S-A) fractal model and a digital elevation model(DEM)-based geochemical model(DGM) was constructed. Finally, the sections of Ag, Cd, Pb, and Zn were obtained using pXRFA. The results show that Ag-Pb-Zn-Cd enrichment zones were mostly located around the contact belt of volcanic rocks and intrusions, or along SE-NW trending faults. Considering the variable terrain and catchment basin, the extension of long axes of Ag-Pb-Zn-Cd anomalies into higher elevation areas that are favorable for Ag-Pb-Zn mineralization should be investigated. Anomaly maps created with the aid of a DGM show promising potential for mineralization in the Dajiacuo-Xurucuo region, and abundant Ag-Pb-Zn mineralization was identified with the assistance of pXRFA in the source areas for the geochemical anomalies in the Dajiacuo. We conclude that SFA and the S-A fractal model constitute a valid tool to identify or verify geochemical anomalies in areas of low-density stream-sediment sampling. The pXRFA can accurately determine the source of geochemical anomalies and improve anomaly verification efficiency.展开更多
Aim:Benign prostatic hyperplasia and prostate cancer is an internationally important health problem of the man,particularly in developed countries.The aim of this exploratory study was to evaluate whether significant ...Aim:Benign prostatic hyperplasia and prostate cancer is an internationally important health problem of the man,particularly in developed countries.The aim of this exploratory study was to evaluate whether significant difference in the levels of Zn and some other trace elements of prostatic fluid exist between the inflamed and malignantly transformed prostate.Methods:Prostatic fluid levels of Br,Fe,Rb,Sr,and Zn were prospectively evaluated in 52 patients with benign prostatic hyperplasia and 24 patients with prostate cancer.Measurements were performed using 109Cd radionuclide-induced energy dispersive X-ray fluorescent microanalysis.Prostatic fluid samples were divided into two portions.One was used for cytological study to exclude prostatitis,while the other was intended for trace element analysis.Results:Mean values±standard error of means for concentration(mg/L)of trace element in the prostatic fluid of hyperplastic prostate were:Br 2.32±0.30,Fe 11.5±1.8,Rb 1.70±0.23,Sr 1.41±0.26,and Zn 488±42.The contents of Rb and Zn were significantly lower(approximately 3.2 and 7.7 times,respectively)in fluid of cancerous prostate compared with those in fluid of hyperplastic prostate.Conclusion:There are significant differences in trace element contents in the fluid of hyperplastic and malignantly transformed prostate.The great decrease in levels of Rb and Zn in the fluid of cancerous prostate might demonstrate ;an involvement of these trace elements in etiology and pathogenesis of malignant prostate tumors.It was supposed that the differences in Rb and Zn levels in prostatic fluid can be used as tumor markers.展开更多
文摘The properties of synthetic graphite materials, widely used in advanced fields, are determined by their structure, which is formed in the process of high-temperature (~2500<span style="white-space:normal;"><span style="white-space:nowrap;">°</span></span><span style="white-space:normal;"></span>C) heat treatment. The fine structure of a graphitizing carbon material based on petroleum coke containing 1.3 wt% S at various stages of graphitization was studied by X-ray diffraction analysis. Some of the samples contained the addition of dispersed Fe<sub>2</sub>O<sub>3</sub>. It is shown that the heat-treated material in the range 1200<span style="white-space:normal;"><span style="white-space:nowrap;">°</span></span><span style="white-space:normal;"></span>C - 2600<span style="white-space:normal;"><span style="white-space:nowrap;">°</span></span><span style="white-space:normal;"></span>C is heterogeneous, its component composition is determined by the processing temperature and the presence of Fe<sub>2</sub>O<sub>3</sub> additive. The observed dependence of the component composition on the heat treatment temperature suggests that the process of graphitization of the carbon material, apparently, develops through a number of metastable states.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07202005).
文摘Phosphorus(P)is an essential and limited resource.Incineration sewage sludge ash(ISSA)contains a high amount of P,which can be recovered using chemical leaching methods.However,the recovery ratio depends on the speciation of P and the leaching conditions.In this study,hydrochloric acid was used as a leaching agent,and the effects of the hydrochloric acid concentration,leaching time,temperature,and liquid-solid ratio on the P leaching ratio were investigated.Furthermore,the co-leaching of macro-metals Ca,Al,Fe,and Mg was analyzed.The results showed that P leached rapidly within 30 min,where the leaching rate reached more than 80%and then gradually stabilized.The leaching concentrations of Ca and Mg had a significant correlation(correlation coefficient r^(2)>0.90),and both were leached completely.Al and P had similar leaching patterns,where the leaching rates increased initially and then decreased with time at 0.2 mol/L HCl.According to X-ray diffraction analysis and Rietveld refinement,the P in ISSA was mainly present in the forms of Mg_(3)Ca_(3)(PO_(4))_(4) and AlPO_(4).When leached using 0.2 mol/L HCl at 55℃ with a liquid-to-solid ratio of 20 L/kg,the AlPO_(4) and Fe_(3)(H_(2)O)_(3)(PO_(4))_(2) in ISSA dissolved initially and then precipitated on the surface of the solid phase,thereby impeding further P leaching.
文摘ZnO films were deposited on glass substrates by means of a direct current (DC) sputtering technique. The physical properties of the films were investigated on the basis of X-ray diffraction measurements. It was found that as-deposited films show c-axis oriented crystal normal to the surface with the extension of c axis by 1.27% that is estimated from the shift of the peak in the X-ray diffraction pattern. Post-deposition annealing in air at higher than 400℃ eliminates the shift and sharpens the diffraction peak structure at the same time. The electrical resistivity continues to decrease from 500 Ω•cm down to 0.6 Ω•cm by annealing as high as 600℃.
基金the National Natural Science Foundation of China for the project support (No. 29972021 )
文摘A series of novel enantiomerically pure diols were synthesized from D-erythorbic acid in three steps, and the absolute configuration of one of them 4a has been confirmed by X-ray analysis.
文摘The title compound, FeCl<sub>4</sub>(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>)(C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>) consists of two [(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>) (C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>)]<sup>+</sup> organic cations and [FeCl<sub>4</sub>]<sup>-</sup> anion. The geometry of the iron ion is tetrahedral, formed by four chlorine atoms. The complex was characterized by single crystal X-ray diffraction, Fourier Transform Infrared spectroscopy, thermal analysis and UV-Visible spectroscopy. Hirshfeld surface analysis was also used for understanding the intermolecular interactions in the crystal packing. Single-crystal X-ray diffraction analysis indicates that this complex crystallizes in the monoclinic system, P2<sub>1</sub>/c space group with a = 7.598 (3) Å, b = 13.694 (4) Å, c = 17.105 (5) Å, <i>β</i><i> </i>= 97.203 (6)° V = 1765.7 (10) Å<sup>3</sup> and Z = 4. The [FeCl<sub>4</sub>]<sup>-</sup> anion and [(C<sub>5</sub>N<sub>2</sub>H<sub>6</sub>)(C<sub>5</sub>N<sub>2</sub>H<sub>5</sub>)]<sup>+</sup> cations are linked through three-dimensional hydrogen-bonding network consisting of N-H...Cl and π-π interactions. Hirshfeld surface analysis and the related 2D fingerprint plots reveal that the complex is dominated by N-H...Cl contacts.
基金This work was supported by the Natural Science Foundation of Shaanxi Province (No. 01JK080 and 02JS40).
文摘Trans-2,2?,4,4?-tetramethyl-6,6?-dinitro azobenzene (C16H16N4O4, Mr = 328.32) was isolated from benzene extract of the leaves of Aconitum sungpanense Hand. Mazz. as a new compound, and characterized by spectral methods and X-ray diffraction analysis. It crystallizes in monoclinic system, space group P21/c with a = 8.544(1), b = 13.997(2), c = 7.161(1) ? ?= 112.97(1), V = 788.4(2) ?, Z = 4, Dc = 1.383 g/cm3, F(000) = 344 and ?MoKa) = 0.102 mm-1. The final R = 0.0395 and wR = 0.1140 for 1913 independent reflections with Rint = 0.0109 and 1329 observed reflections with I > 2s(I). The molecule is composed of two phenyl rings through trans N=N.
基金Supported by the State "863" High Sci-tech Program of China (2003AA246060)
文摘1’,4’-Trans-diol of abscisic acid was isolated from botrytis cinerea as a colorless crystal. The molecular and crystal structures have been determined by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with a = 6.724(3), b = 17.559(6), c = 12.265(2) , α = β = γ = 90o, V = 1448.1(8) 3, Z = 4, Dx = 1.222 g/cm3, F(000) = 576 and μ(MoKa) = 0.087 mm-1. The final R = 0.0628 and wR = 0.1604 for 2501 independent reflections with Rint = 0.0160 and 1679 observed reflections with I >2σ(I). There are three intermolecular hydrogen bonds in a unit cell.
文摘anhydro-2-triflyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5’-O-TBS-2’,3’-di-O-acetyl-N1-(2’’-deoxy-1",4"-anhydro-3’’,5’’-O-benzenylidene-L- lyxitol-2’’-yl)-8-bromoinosine (14). Selective removal of 5’-O-TBS-group gave the corresponding 5’-O-phosphorodianilidate 4 though phosphorylation, which was characterized by X-ray crystallographic analysis.
基金funding support from BSIP in the form of In-house Project No.2.17(XIII five-year plan)。
文摘This paper reviews research on coprolites from India,providing the first evidence of microcoprolites from the early Miocene(Aquitanian)Khari Nadi Formation sedimentary succession,exposed about 1.5 km northeast of the village of Kotada,Kachchh(Kutch)District,Gujarat State,western India.Morphometric and size comparisons(in a statistical framework)with known coprolites from the Mesozoic-Cenozoic successions of India(including those recorded herein)and globally suggest that fishes were the likely producers of the Kotada coprolites.Scanning electron microscopy confirms the presence of fish dental remains within the coprolites,while both Scanning Electron Microscopy(SEM)and Energy Dispersive X-ray Spectroscopy(EDS)reveal the phosphatic nature of the microscopic coprolite specimens(recorded herein)hinting that the producer(s)were predominantly carnivorous(ichthyophagous)in their diet.Furthermore,X-Ray Fluorescence(XRF)analysis of the host and associated lithologies allows us to deduce that the Kotada coprolites were deposited in a shallow marine environment,with possible aerial exposure of the host lithology occurring at some point after deposition.To the best of our knowledge,the present report is the first record of microscopic fish coprolites from India,as well as being the first from the Aquitanian of India and the oldest Neogene record from India.
文摘The influence of two-stage isothermal treatment on the change in the linear dimensions of the fiber, the average sizes of the coherent scattering regions, the texture and phase composition of the polyacrylonitrile fiber in the process of isothermal thermal stabilization is considered by the methods of dilatometry and X-ray diffraction analysis. It is shown that preliminary short-term heat treatment at a lower temperature affects the process of structural transformations of the polyacrylonitrile fiber material and the formation of a new highly dispersed phase of the thermally stabilized fiber.
文摘Determining the contents of F,S(total),and Cl in the studied samples of the limestone and marbles with high calcite contents was carried out by the nondestructive method of WDXRFS(Wavelength Dispersive X-ray Fluorescence Spectrometry).All measurements were performed in a vacuum condition using a WDXRF spectrometer S8 TIGER(Bruker AXS,Germany).The studied samples have wide ranges of F,S(total),and Cl contents,and high concentration of calcite(89.5%-99%).Main objective of this research is to develop WDXRF(WD X-ray fluorescence)technique for the determination of F,S(total),and Cl.The calculated values of the ILD(instrumental limit of the detection)were within the interval from 3 for S(total)to 37 for F mg/kg.The repeatability was found to be satisfactory with the relative standard deviations lower than 7%.
文摘The evaluation of the effect of using moringa oleifera seed powder(MOSP)to partially replace cement by wt.%has been carried out.A mix parameter of 1:1.7:2.5,with designed strength of 20 kN-m^(2),and a cement content of 420 kg-m3,water-cementitious ratio of 0.5,to produce concrete specimens to which percentages of MOSP by wt.%of cement were added and cured for 90 days.Basic characteristics of the MOSP material were determined(Consistency and Setting times),and the concrete parameters workability,density,water absorption and compressive strength were also determined.The analysis of the experimental data collected on MOSP and MOSP-concrete confirmed that MOSP is substantially silicate(Quartz and Cristobalite).These have greatly to a large extent imparted on the quality of MOSP-concrete produced good quality concrete.The optimum replacement was at 0.2%wt.%of cement.
文摘1 Results We have recently reported the Mizoroki-Heck reaction catalyzed by PdCl2 and imidazole ligands[1]. During the course of our study of palladium imidazole complex,we disclosed the synthesis of trans-Pd(Ln)2Cl2 by the reaction of PdCl2 with Ln (where L1=2-phenylimidazole,L2=2-phenylimidazole) in a 1∶2 molar ratio.The single crystals of trans-Pd(L1)2Cl2·2DMF (1a) and trans-Pd(L2)2Cl2 (2a) were obtained by following slow evaporation of DMF as a solvent. The single crystal of trans-Pd(L2)2Cl2 (2b) w...
基金This work was supported by the Ministry of High Education and Scientific Research in Tunisia,the Spanish Ministry of Economy and Competitiveness.
文摘In this work,high quality uniform and dense nanostructured cobalt-doped zinc oxide(ZnO:Co)films were used as electron-transport layers in CH3NH3Pbl3-based planar heterojunction perovskite solar cells(PSCs)on a flexible conductive substrate.Highly photo catalytically active ZnO:Co films were prepared by a low cost hydrothermal process using the aqueous solution of zinc nitrate hexahydrate,hexamethylenete-tramine and cobalt(II)nitrate hexahydrate.ZnO:Co films were deposited on indium tin oxide(ITO)covered polyethylene terephthalate(PET)flexible substrates.The growth was controlled by maintaining the autoclave temperature at 150℃for 4 h.The CH3NH3Pbl3 layer was deposited on the ZnO:Co films by spin coating.Spiro-OMeTAD was employed as a hole-transporting material.The structural,morphology and optical properties of the grown ZnO nanostructures were characterized by X-ray diffraction(XRD),field-emission scanning electron microcopy(FESEM),energy-dispersive X-ray spectrometry(EDX),ultraviolet-visible(UV-Vis)and photoelectrochemical propriety.XRD spectra showed that both ZnO and ZnO:Co nanorods had a hexagonal wurtzite structure with a strong preferred orientation along the(002)plane.The surface morphology of films was studied by FESEM and showed that both the pure and Co-doped ZnO films had hexagonal shaped nanorods.In the steady state,the ZnO electrode gave a photocurrent density of about 1.5 mA/cm2.However,the Co-doped ZnO electrode showed a photocurrent density of about 6 mA/cm^2,which is 4-fold higher than that of the ZnO electrode.Based on the above synthesized Co-doped ZnO films,the photovoltaic performance of PSCs was studied.The Co-doped ZnO layers had a significant impact on the photovoltaic conversion efficiency(PCE)of the PSCs.The latter was attributed to an efficient charge separation and transport due to the better coverage of perovskite on the nanostructured Co-doped ZnO films.As a result,the measured PCE under standard solar conditions(A M 1.5G,100 mW/cm^2)reached 7%.SCAPS-1D simulation was also performed to analyze the effect of the co-doped ZnO thin film on the corresponding solar cell performances.
基金funded by the Fundamental Research Funds for the Central UniversitiesChina University of Geosciences (Wuhan)(No. 2019132)China Geological Survey (No. DD20190159-33)。
文摘Tibet, which is rich in mineral resources, is a treasure trove for geological explorers. However, prospecting work has been slow, especially in the western part, due to the precipitous terrain, changeable climate and low access. Hence, modern advanced field analytical technology and effective data processing methods play significant roles in rapid and efficient exploration in Tibet. In this paper, spectrum-area fractal modeling and portable X-ray fluorescence analysis(pXRFA) were used to identify and verify geochemical anomalies associated with Ag-Pb-Zn mineralization based on a stream-sediment dataset of 39 elements in the Dajiacuo-Xurucuo region of western Tibet. First, staged factor analysis(SFA) was used to obtain the Ag-Pb-Zn-Cd geochemical assemblage. Second, the first-factor pattern obtained using SFA was dissociated by a spectrum-area(S-A) fractal model and a digital elevation model(DEM)-based geochemical model(DGM) was constructed. Finally, the sections of Ag, Cd, Pb, and Zn were obtained using pXRFA. The results show that Ag-Pb-Zn-Cd enrichment zones were mostly located around the contact belt of volcanic rocks and intrusions, or along SE-NW trending faults. Considering the variable terrain and catchment basin, the extension of long axes of Ag-Pb-Zn-Cd anomalies into higher elevation areas that are favorable for Ag-Pb-Zn mineralization should be investigated. Anomaly maps created with the aid of a DGM show promising potential for mineralization in the Dajiacuo-Xurucuo region, and abundant Ag-Pb-Zn mineralization was identified with the assistance of pXRFA in the source areas for the geochemical anomalies in the Dajiacuo. We conclude that SFA and the S-A fractal model constitute a valid tool to identify or verify geochemical anomalies in areas of low-density stream-sediment sampling. The pXRFA can accurately determine the source of geochemical anomalies and improve anomaly verification efficiency.
文摘Aim:Benign prostatic hyperplasia and prostate cancer is an internationally important health problem of the man,particularly in developed countries.The aim of this exploratory study was to evaluate whether significant difference in the levels of Zn and some other trace elements of prostatic fluid exist between the inflamed and malignantly transformed prostate.Methods:Prostatic fluid levels of Br,Fe,Rb,Sr,and Zn were prospectively evaluated in 52 patients with benign prostatic hyperplasia and 24 patients with prostate cancer.Measurements were performed using 109Cd radionuclide-induced energy dispersive X-ray fluorescent microanalysis.Prostatic fluid samples were divided into two portions.One was used for cytological study to exclude prostatitis,while the other was intended for trace element analysis.Results:Mean values±standard error of means for concentration(mg/L)of trace element in the prostatic fluid of hyperplastic prostate were:Br 2.32±0.30,Fe 11.5±1.8,Rb 1.70±0.23,Sr 1.41±0.26,and Zn 488±42.The contents of Rb and Zn were significantly lower(approximately 3.2 and 7.7 times,respectively)in fluid of cancerous prostate compared with those in fluid of hyperplastic prostate.Conclusion:There are significant differences in trace element contents in the fluid of hyperplastic and malignantly transformed prostate.The great decrease in levels of Rb and Zn in the fluid of cancerous prostate might demonstrate ;an involvement of these trace elements in etiology and pathogenesis of malignant prostate tumors.It was supposed that the differences in Rb and Zn levels in prostatic fluid can be used as tumor markers.
