Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The...Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The objective of this paper is to study the changes in organic structure and mineral phase transformation during combustion. Different density fractions were generated and then heated at different temperatures from 200 to 1000 ℃. Petrography, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were carried out on all the density fractions aimed to accomplish this objective. Here, through petrography, it was observed that the vitrinite and liptinite macerals disappear at higher temperature while porous inertinite is seen. The inertinite structure is exposed which is assumed by the presence of -OH and C-O-C stretches with the aromatic nucleus (CH) and three to four adjacent H from FTIR spectra. Moreover, it can be concluded that aliphatic groups get collapsed at high temperature. In case of inorganic matter, through XRD and FTIR, it is also revealed that with increasing temperature, clay minerals converted into elemental oxides. Hence, this study is suggesting that the structures of coal are altered by the degree of contact metamorphism.展开更多
This article aims to study the history of scientific investigations in China in the nineteenth century,made by Russian scientists who ranged in status and position including official agents,the directors of the Russia...This article aims to study the history of scientific investigations in China in the nineteenth century,made by Russian scientists who ranged in status and position including official agents,the directors of the Russian Magneto-Meteorological Observatory in Beijing,the members of the Russian Orthodox Mission(ROM),and others.The article gives a detailed analysis of the unique expeditions of H.Fritsche(1839–1913),director of the Russian Magneto-Meteorological Observatory in Beijing,and Archimandrite Palladius(1817–1878),head of the ROM to the northeast part of China.During those expeditions,existing maps were corrected and new maps were made.The article also covers the history of natural science investigations,made by other members of missions,doctors,and attached persons.This article employs sources from Russian archives(Saint Petersburg Branch of the Archive of the Russian Academy of Sciences,Russian State Historical Archive,Archive of the Foreign Policy of the Russian Empire),which were rarely used by the scientific community,and adopts an empirical approach based on objectivity and historicism to the sources and research.展开更多
Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based ...Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based upon a discernible matrix of the fractal dimension associated with line currents.The method builds on existing selective protection methods.Faulted feeders are distinguished using differences in the zero-sequence transient current fractal dimension.The current signals were first processed through a fast Fourier transform and then the characteristics of a faulted line were identified using a discernible matrix.The method of calculation is illustrated.The results show that the method involves simple calculations, is easy to do and is highly accurate.It is, therefore, suitable for distribution networks having different neutral grounding modes.展开更多
The structure of Ni active sites supported on amorphous silica-alumina supports with different contents of Al_(2)O_(3)loadings in relation to their activities in ethylene oligomerization were investigated.Two kinds of...The structure of Ni active sites supported on amorphous silica-alumina supports with different contents of Al_(2)O_(3)loadings in relation to their activities in ethylene oligomerization were investigated.Two kinds of Ni sites were detected by in situ FTIR-CO and H_(2)-TPR experiments,that are Ni^(2+)cations as grafted on weak acidic silanols and Ni^(2+)cations at ion-exchange positions.The ethylene oligomerization activities of these Ni/ASA catalysts were found an ascending tendency as the Al_(2)O_(3)loading decreased,which could be attributed to the enriched concentration of Ni^(2+)species on acidic silanols with a weaker interaction with the amorphous silica-alumina support.These Ni^(2+)species were more easily to be evolved into Ni^(+)species,which has been identified to be the active sites of ethylene oligomerization.Thus,it seems reasonable to conclude that Ni^(2+)species grafted on acidic silanols were the precursors of active sites.展开更多
This paper proposes a new method for extracting ENF (electric network frequency) fluctuations from digital audio recordings for the purpose of forensic authentication. It is shown that the extraction of ENF componen...This paper proposes a new method for extracting ENF (electric network frequency) fluctuations from digital audio recordings for the purpose of forensic authentication. It is shown that the extraction of ENF components from audio recordings is realizable by applying a parametric approach based on an AR (autoregressive) model. The proposed method is compared to the existing STFT (short-time Fourier transform) based ENF extraction method. Experimental results from recorded electrical grid signals and recorded audio signals show that the proposed approach can improve the time resolution in the extracted ENF fluctuations and improve the detection of tampering with short alterations in longer audio recordings.展开更多
The mineralogy and trace element contents in coals from the West Bokaro coalfield, which is the one of the biggest Gondwana coalfields of India, were studied to delineate enrichment of trace elements and their modes o...The mineralogy and trace element contents in coals from the West Bokaro coalfield, which is the one of the biggest Gondwana coalfields of India, were studied to delineate enrichment of trace elements and their modes of occur- rence. Elemental concentrations with reference to their crustal abundances indicated that coals are relatively enriched in As (4.4-15.5 mg/kg), Cd (0.3-3.0 mg/kg), Cu (28.0-68.1 mg/kg) and V (46.6-178.0 mg/kg); depleted in Co (10.8-28.4 mg/ kg), Mn (7.6-483.4 mg/kg), Ni (13.0-31.6 mg/kg), Cr (14.2-85.5 mg/kg) and Zn (5.25-70.4 mg/kg). The concentration of As, Cd, Co, Cu and V were higher than the average values of world and Indian coals. Mineralogical study carried out by X-ray diffraction shows that quartz and kaolinite occur as dominant mineral phases in this coal. Fourier transform infrared spectroscopy pattern suggests organic structures primarily containing aromatic nuclei, aliphatic side chain and some oxygen containing groups. The modes of occurrence of trace elements present in these coals have been determined through statistical approach. Both Cu and Cr are more closely associated with mineral matter, whereas Co is dominantly present with its organic form. The concentrations of Cd, Mn, Ni, Zn, As and V have apparently occur in both organic and inorganic constituents. This study would be helpful to assess the potential environmental impacts during mining and combustion of this coal.展开更多
Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier...Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization)The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.展开更多
This paper presents a new earth-fault detection algorithm for unearthed (isolated) and compensated neutral medium voltage (MV) networks. The proposed algorithm is based on capacitance calculation from transient im...This paper presents a new earth-fault detection algorithm for unearthed (isolated) and compensated neutral medium voltage (MV) networks. The proposed algorithm is based on capacitance calculation from transient impedance and dominant transient frequency. The Discrete Fourier Transform (DFT) method is used to determine the dominant transient frequency. The values of voltage and current earth modes are calculated in the period of the dominant transient frequency, then the transient impedance can be determined, from which we can calculate the earth capacitance. The calculated capacitance gives an indication about if the feeder is faulted or not. The algorithm is less dependent on the fault resistance and the faulted feeder parameters; it mainly depends on the background network. The network is simulated by ATP/EMTP program. Several different fault conditions are covered in the simulation process, different fault inception angles, fault locations and fault resistances.展开更多
The pyrolysis of different waste polymers (polyethylene, polypropylene and polystyrene) was investigated in a tube reactor at 550 ℃ in the absence of oxygen. Additionally the energetic utilization of products have ...The pyrolysis of different waste polymers (polyethylene, polypropylene and polystyrene) was investigated in a tube reactor at 550 ℃ in the absence of oxygen. Additionally the energetic utilization of products have also been followed both in refining and petrochemical industry. Pyrolysis products were separated into fractions of gases, naphtha, middle distillates and heavy oil. Raw materials have been collected both from industrial and household sources: polyethylene from agriculture, polyethylene from packaging and polystyrene from packaging and electronic equipments. Yields and properties of volatile products have changed by the raw materials. Products have been analyzed by gas chromatography. Fourier transformed infrared spectroscopy, size exclusion chromatography and other standardized methods. Naphtha had high octane numbers (80 〈 RON), while high cetane numbers (〉 75) in case of middle distillates. Moreover fractions contained approximately half of unsaturated hydrocarbons, mainly α-olefins, but the percentage was depending on the raw materials. These properties are advantageous for fuel-like applications.展开更多
Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of pre...Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of precision spectroscopy and trace gas detection.Here,we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell.Using this instrument,the broadband absorption spectra of several important molecules,including methane,acetylene,water molecules and nitrous oxide,are measured by near real-time data acquisition in the 2800-3500 cm^(-1)spectral region.The achieved minimum detectable absorption of the instrument is 4.4×10^(-8)cm^(-1)·Hz^(-1/2)per spectral element.Broadband spectra of H_(2)0 are fited using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%.Our system also enables precise spectroscopic measurements,and it allows the determination of the spectral line positions and upper state constants of N_(2)O in the(0002)-(1000)band,with results in good agreement with those reported by Toth[Appl.Opt.30,5289(1991)].展开更多
Water has become an effective means to trace the mantle source of basaltic magmas recently. To investigate the source of the potassium-rich component in the Xiaogulihe ultrapotassic volcanic rocks of NE China, we meas...Water has become an effective means to trace the mantle source of basaltic magmas recently. To investigate the source of the potassium-rich component in the Xiaogulihe ultrapotassic volcanic rocks of NE China, we measured the water content of clinopyroxene (cpx) phenocrysts by Fourier transform infrared spectrometry and calculated the H2O content of the equilibrated melts according to the partition coefficients of H2O between cpx phenocrysts and basaltic melts. The estimated H2O content of the "primary" magmas is low (0.36 wt%-0.50 wt%), within the range of mid-ocean ridge basalts and ocean island basalts, while it is obviously lower than that of backarc basin basalts and island arc basalts. The calculated H20/Ce ratio of the "primary" magmas is about 15, which might be similar to that of the dehydrated sediments (〈100), but observably lower than that of the normal depleted mantle (DMM, H2O/Ce = 150-210). The low water content and especially low H2O/Ce ratio of the "primary" magmas demonstrate that the K-rich component of these ultrapotassic volcanic rocks seems unlikely tooriginate from K-bearing hydrous minerals (such as phlogopite) in metasomatic subcontinental lithospheric mantle. Combined with the low 206pb/204pb ratios, moderately high 87Sr/86Sr ratios of the bulk rocks and the high δ18O values of olivine phenocrysts, we suggest that the K-rich component in the mantle source of the Xiaogulihe ultrapotassic volcanic rocks may come from ancient continental-derived sediments which dehydrated significantly during subduction (e.g., dry K-hollandite).展开更多
Ammonia (NH3) volatilization is one of the important pathways of nitrogen loss in alkaline soil, and the NH3 concentration in soil headspace is directly linked with the NH3 volatilization. Ammonia was characterized ...Ammonia (NH3) volatilization is one of the important pathways of nitrogen loss in alkaline soil, and the NH3 concentration in soil headspace is directly linked with the NH3 volatilization. Ammonia was characterized by Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS) and two typical absorption bands in the region of 850-1 200 cm-1 were observed, which could be used for the prediction of NH3 concentration in the soil headspaze. An alkaline soil from North China was involved in the soil incubation, pot and field experiments under three fertilization treatments (control without N input (CK), urea and coated urea). Ammonia concentrations in the soil headspace were determined in each experiment. In the soil incubation experiment, the NH3 emissions were initiated by the N input, reached the highest concentration on day 2, and decreased to the level as measured in CK after 8 d, with significantly higher NH3 emissions in the urea treatment compared to coated urea treatment, especially during the first 4 d. The NH3 concentration in soil headspace of the pot experiment showed the similar dynamics as that in the incubation experiment; however, the NH3 concentration in the soil headspace in the field experiment demonstrated a significantly different emission pattern with those of the incubation and pot experiments, and there was a 4-d delay for the NH3 concentration. Therefore, the NH3 concentration in the incubation and pot experiments could not be directly used to model the real NH3 emission in the field due to the differences in fertilization method and application rate as well as soil temperature and soil disturbance. It was recommended that light irrigation in the second week after fertilization and involvement of controlled release coated urea could be used to significantly decrease N loss from the perspective of NH3 volatilization. Key Words: ammonia volatilization, cantilevel-type microphone, nitrogen, principal component regression, soil incubation.展开更多
This paper deals with the backscatter coefficients known as sigma0 at Ku band and C band based on the GDR-M (Merged Geophysical Data Record) of TOPEX/Poseidon (T/P) through Jan.1993 to Dec.2004 over land surface of Ch...This paper deals with the backscatter coefficients known as sigma0 at Ku band and C band based on the GDR-M (Merged Geophysical Data Record) of TOPEX/Poseidon (T/P) through Jan.1993 to Dec.2004 over land surface of China.After smoothing and interpolating the backscatter coefficients for both bands, we achieve the 5′×5′ grid data and the time series of backscatter coefficients in 12 years.The spatial distribution of sigma0 over typical areas (wetland, desert, mountainous area, agriculture base, etc.) of Chinese territory is analyzed and discussed.The fast Fourier transformation (FFT) is used to detect the cycles of seasonal variations of sigma0 time series and gives that the annual period is the major cycle.Meanwhile a semiannual period is also found in some places.We use the least squares method on both periods and find that the amplitude of annual period is obviously greater than that of semi-annual period.The relationship among the anomalousness of time series, variations of environment and climate change, and the serious natural calamity (flood, drought) is also discussed.Data of topography slope extracted from SRTM are used to do correlation analysis with the backscatter coefficients in parts of China to quantify the impact of slope on backscatter coefficients in Ku and C bands, and the results show that they all have a negative correlation but the magnitudes are different in different places with different coverages.Such as the area of Liaoning and Jilin has the maximum correlation -0.56, the Taklimakan Desert has the minimum correlation -0.11, and the other places commonly have correlations in (-0.3, -0.5).展开更多
文摘Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The objective of this paper is to study the changes in organic structure and mineral phase transformation during combustion. Different density fractions were generated and then heated at different temperatures from 200 to 1000 ℃. Petrography, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were carried out on all the density fractions aimed to accomplish this objective. Here, through petrography, it was observed that the vitrinite and liptinite macerals disappear at higher temperature while porous inertinite is seen. The inertinite structure is exposed which is assumed by the presence of -OH and C-O-C stretches with the aromatic nucleus (CH) and three to four adjacent H from FTIR spectra. Moreover, it can be concluded that aliphatic groups get collapsed at high temperature. In case of inorganic matter, through XRD and FTIR, it is also revealed that with increasing temperature, clay minerals converted into elemental oxides. Hence, this study is suggesting that the structures of coal are altered by the degree of contact metamorphism.
文摘This article aims to study the history of scientific investigations in China in the nineteenth century,made by Russian scientists who ranged in status and position including official agents,the directors of the Russian Magneto-Meteorological Observatory in Beijing,the members of the Russian Orthodox Mission(ROM),and others.The article gives a detailed analysis of the unique expeditions of H.Fritsche(1839–1913),director of the Russian Magneto-Meteorological Observatory in Beijing,and Archimandrite Palladius(1817–1878),head of the ROM to the northeast part of China.During those expeditions,existing maps were corrected and new maps were made.The article also covers the history of natural science investigations,made by other members of missions,doctors,and attached persons.This article employs sources from Russian archives(Saint Petersburg Branch of the Archive of the Russian Academy of Sciences,Russian State Historical Archive,Archive of the Foreign Policy of the Russian Empire),which were rarely used by the scientific community,and adopts an empirical approach based on objectivity and historicism to the sources and research.
基金Project 50504015 supported by the National Natural Science Foundation of Chinathe Youth Science and Technology Research Program of China University of Mining and Technology (0C060996)
文摘Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based upon a discernible matrix of the fractal dimension associated with line currents.The method builds on existing selective protection methods.Faulted feeders are distinguished using differences in the zero-sequence transient current fractal dimension.The current signals were first processed through a fast Fourier transform and then the characteristics of a faulted line were identified using a discernible matrix.The method of calculation is illustrated.The results show that the method involves simple calculations, is easy to do and is highly accurate.It is, therefore, suitable for distribution networks having different neutral grounding modes.
文摘The structure of Ni active sites supported on amorphous silica-alumina supports with different contents of Al_(2)O_(3)loadings in relation to their activities in ethylene oligomerization were investigated.Two kinds of Ni sites were detected by in situ FTIR-CO and H_(2)-TPR experiments,that are Ni^(2+)cations as grafted on weak acidic silanols and Ni^(2+)cations at ion-exchange positions.The ethylene oligomerization activities of these Ni/ASA catalysts were found an ascending tendency as the Al_(2)O_(3)loading decreased,which could be attributed to the enriched concentration of Ni^(2+)species on acidic silanols with a weaker interaction with the amorphous silica-alumina support.These Ni^(2+)species were more easily to be evolved into Ni^(+)species,which has been identified to be the active sites of ethylene oligomerization.Thus,it seems reasonable to conclude that Ni^(2+)species grafted on acidic silanols were the precursors of active sites.
文摘This paper proposes a new method for extracting ENF (electric network frequency) fluctuations from digital audio recordings for the purpose of forensic authentication. It is shown that the extraction of ENF components from audio recordings is realizable by applying a parametric approach based on an AR (autoregressive) model. The proposed method is compared to the existing STFT (short-time Fourier transform) based ENF extraction method. Experimental results from recorded electrical grid signals and recorded audio signals show that the proposed approach can improve the time resolution in the extracted ENF fluctuations and improve the detection of tampering with short alterations in longer audio recordings.
文摘The mineralogy and trace element contents in coals from the West Bokaro coalfield, which is the one of the biggest Gondwana coalfields of India, were studied to delineate enrichment of trace elements and their modes of occur- rence. Elemental concentrations with reference to their crustal abundances indicated that coals are relatively enriched in As (4.4-15.5 mg/kg), Cd (0.3-3.0 mg/kg), Cu (28.0-68.1 mg/kg) and V (46.6-178.0 mg/kg); depleted in Co (10.8-28.4 mg/ kg), Mn (7.6-483.4 mg/kg), Ni (13.0-31.6 mg/kg), Cr (14.2-85.5 mg/kg) and Zn (5.25-70.4 mg/kg). The concentration of As, Cd, Co, Cu and V were higher than the average values of world and Indian coals. Mineralogical study carried out by X-ray diffraction shows that quartz and kaolinite occur as dominant mineral phases in this coal. Fourier transform infrared spectroscopy pattern suggests organic structures primarily containing aromatic nuclei, aliphatic side chain and some oxygen containing groups. The modes of occurrence of trace elements present in these coals have been determined through statistical approach. Both Cu and Cr are more closely associated with mineral matter, whereas Co is dominantly present with its organic form. The concentrations of Cd, Mn, Ni, Zn, As and V have apparently occur in both organic and inorganic constituents. This study would be helpful to assess the potential environmental impacts during mining and combustion of this coal.
基金the financial support by the Fundamental Research Funds for the Central Universities (No.2010QNA14)
文摘Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization)The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.
文摘This paper presents a new earth-fault detection algorithm for unearthed (isolated) and compensated neutral medium voltage (MV) networks. The proposed algorithm is based on capacitance calculation from transient impedance and dominant transient frequency. The Discrete Fourier Transform (DFT) method is used to determine the dominant transient frequency. The values of voltage and current earth modes are calculated in the period of the dominant transient frequency, then the transient impedance can be determined, from which we can calculate the earth capacitance. The calculated capacitance gives an indication about if the feeder is faulted or not. The algorithm is less dependent on the fault resistance and the faulted feeder parameters; it mainly depends on the background network. The network is simulated by ATP/EMTP program. Several different fault conditions are covered in the simulation process, different fault inception angles, fault locations and fault resistances.
文摘The pyrolysis of different waste polymers (polyethylene, polypropylene and polystyrene) was investigated in a tube reactor at 550 ℃ in the absence of oxygen. Additionally the energetic utilization of products have also been followed both in refining and petrochemical industry. Pyrolysis products were separated into fractions of gases, naphtha, middle distillates and heavy oil. Raw materials have been collected both from industrial and household sources: polyethylene from agriculture, polyethylene from packaging and polystyrene from packaging and electronic equipments. Yields and properties of volatile products have changed by the raw materials. Products have been analyzed by gas chromatography. Fourier transformed infrared spectroscopy, size exclusion chromatography and other standardized methods. Naphtha had high octane numbers (80 〈 RON), while high cetane numbers (〉 75) in case of middle distillates. Moreover fractions contained approximately half of unsaturated hydrocarbons, mainly α-olefins, but the percentage was depending on the raw materials. These properties are advantageous for fuel-like applications.
基金supported by the National Natural Science Foundation China(No.42022051,No.U21A2028)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202089)the HFIPS Director's Fund(No.YZJJ202101,No.BJPY2023A02).
文摘Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of precision spectroscopy and trace gas detection.Here,we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell.Using this instrument,the broadband absorption spectra of several important molecules,including methane,acetylene,water molecules and nitrous oxide,are measured by near real-time data acquisition in the 2800-3500 cm^(-1)spectral region.The achieved minimum detectable absorption of the instrument is 4.4×10^(-8)cm^(-1)·Hz^(-1/2)per spectral element.Broadband spectra of H_(2)0 are fited using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%.Our system also enables precise spectroscopic measurements,and it allows the determination of the spectral line positions and upper state constants of N_(2)O in the(0002)-(1000)band,with results in good agreement with those reported by Toth[Appl.Opt.30,5289(1991)].
基金supported by the National Natural Science Foundation of China(41225005)the Research Fund for the Doctoral Program of Higher Education of China(RFDP20113402130001)
文摘Water has become an effective means to trace the mantle source of basaltic magmas recently. To investigate the source of the potassium-rich component in the Xiaogulihe ultrapotassic volcanic rocks of NE China, we measured the water content of clinopyroxene (cpx) phenocrysts by Fourier transform infrared spectrometry and calculated the H2O content of the equilibrated melts according to the partition coefficients of H2O between cpx phenocrysts and basaltic melts. The estimated H2O content of the "primary" magmas is low (0.36 wt%-0.50 wt%), within the range of mid-ocean ridge basalts and ocean island basalts, while it is obviously lower than that of backarc basin basalts and island arc basalts. The calculated H20/Ce ratio of the "primary" magmas is about 15, which might be similar to that of the dehydrated sediments (〈100), but observably lower than that of the normal depleted mantle (DMM, H2O/Ce = 150-210). The low water content and especially low H2O/Ce ratio of the "primary" magmas demonstrate that the K-rich component of these ultrapotassic volcanic rocks seems unlikely tooriginate from K-bearing hydrous minerals (such as phlogopite) in metasomatic subcontinental lithospheric mantle. Combined with the low 206pb/204pb ratios, moderately high 87Sr/86Sr ratios of the bulk rocks and the high δ18O values of olivine phenocrysts, we suggest that the K-rich component in the mantle source of the Xiaogulihe ultrapotassic volcanic rocks may come from ancient continental-derived sediments which dehydrated significantly during subduction (e.g., dry K-hollandite).
基金supported by the National Natural Science Foundation of China (No. 41130749)the National Basic Research Program (973 Program) of China (No. 2015CM15043)
文摘Ammonia (NH3) volatilization is one of the important pathways of nitrogen loss in alkaline soil, and the NH3 concentration in soil headspace is directly linked with the NH3 volatilization. Ammonia was characterized by Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS) and two typical absorption bands in the region of 850-1 200 cm-1 were observed, which could be used for the prediction of NH3 concentration in the soil headspaze. An alkaline soil from North China was involved in the soil incubation, pot and field experiments under three fertilization treatments (control without N input (CK), urea and coated urea). Ammonia concentrations in the soil headspace were determined in each experiment. In the soil incubation experiment, the NH3 emissions were initiated by the N input, reached the highest concentration on day 2, and decreased to the level as measured in CK after 8 d, with significantly higher NH3 emissions in the urea treatment compared to coated urea treatment, especially during the first 4 d. The NH3 concentration in soil headspace of the pot experiment showed the similar dynamics as that in the incubation experiment; however, the NH3 concentration in the soil headspace in the field experiment demonstrated a significantly different emission pattern with those of the incubation and pot experiments, and there was a 4-d delay for the NH3 concentration. Therefore, the NH3 concentration in the incubation and pot experiments could not be directly used to model the real NH3 emission in the field due to the differences in fertilization method and application rate as well as soil temperature and soil disturbance. It was recommended that light irrigation in the second week after fertilization and involvement of controlled release coated urea could be used to significantly decrease N loss from the perspective of NH3 volatilization. Key Words: ammonia volatilization, cantilevel-type microphone, nitrogen, principal component regression, soil incubation.
基金supported by National Natural Science Founda-tion of China(Grant Nos.40974004 and 40774009)International Sci&Tech Cooperation Program of China(Grant No.2009DFB00130)+1 种基金Key Laboratory of Mapping from Space of NASMG,China(Grant No.K201103)the R&I Team Supporting Program and Graduate Sci.&Tech Innovation Fund of SDUST,China(Grant No.YCB110010)
文摘This paper deals with the backscatter coefficients known as sigma0 at Ku band and C band based on the GDR-M (Merged Geophysical Data Record) of TOPEX/Poseidon (T/P) through Jan.1993 to Dec.2004 over land surface of China.After smoothing and interpolating the backscatter coefficients for both bands, we achieve the 5′×5′ grid data and the time series of backscatter coefficients in 12 years.The spatial distribution of sigma0 over typical areas (wetland, desert, mountainous area, agriculture base, etc.) of Chinese territory is analyzed and discussed.The fast Fourier transformation (FFT) is used to detect the cycles of seasonal variations of sigma0 time series and gives that the annual period is the major cycle.Meanwhile a semiannual period is also found in some places.We use the least squares method on both periods and find that the amplitude of annual period is obviously greater than that of semi-annual period.The relationship among the anomalousness of time series, variations of environment and climate change, and the serious natural calamity (flood, drought) is also discussed.Data of topography slope extracted from SRTM are used to do correlation analysis with the backscatter coefficients in parts of China to quantify the impact of slope on backscatter coefficients in Ku and C bands, and the results show that they all have a negative correlation but the magnitudes are different in different places with different coverages.Such as the area of Liaoning and Jilin has the maximum correlation -0.56, the Taklimakan Desert has the minimum correlation -0.11, and the other places commonly have correlations in (-0.3, -0.5).