Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtrop...Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two planta- tions of Schima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO3 -N, NH4 -N and total dissolved N (TDN). DON was calculated by subtracting NO3 -N and NH4 -N from TDN. The results - + - + showed that the precipitation had a mean DOC concentration of 1.7 mg·L-1 and DON concentration of 0.13 mg·L-1. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L-1 in the SS and 10.3 and 0.19 mg·L-1 in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L-1 respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L-1 respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipita- tion tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September-November period.展开更多
Vertebrate Msx genes are unlinked,homeobox-containing genes that bear homology to the Drosophila muscle segment homeobox gene.These genes are expressed at multiple sites of tissue-tissue interactions during vertebrate...Vertebrate Msx genes are unlinked,homeobox-containing genes that bear homology to the Drosophila muscle segment homeobox gene.These genes are expressed at multiple sites of tissue-tissue interactions during vertebrate embryonic development.Inductive interactions mediated by the Msx genes are essential for normal craniofacial,limb and ectodermal organ morphogenesis,and are also essential to survival in mice,as manifested by the phenotypic abnormalities shown in knockout mice and in humans.This review summarizes studies on the expression,regulation,and functional analysis of Msx genes that bear relevance to craniofacial development in humans and mice.展开更多
Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in ...Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in topsoils (0-10 cm)were quantified in two 33-year-old monoculture plantations of Castanopsis kawakamii Hayata (CK) and Cunninghamia lanceolata Lamb. (Chinese fir) (CF), and compared to a neighboring relict natural C. kawakamii forest (NF), in Sanming,Fujian. Five soil samples were collected once each in January, April, July, September and November in 2000 in each forest for laboratory analysis. Over the sampling year, there were significant differences for bacteria, fungi and actinomycetes between forests and between seasons (P ＜ 0.05). The largest bacteria and fungi populations were in NF, while CF contained the greatest number of actinomycetes. There were also significant differences (P ＜ 0.05) with microbial respiration for forests and seasons. Additionally, compared with NF, urease and acid phosphatase were significantly lower (P ＜ 0.05)in CK and CF. Also, the correlations of soil hydrolysable N and available P to soil microbial and enzymatic activities were highly significant (P ＜ 0.01). Thus, to alter the traditional Chinese fir monoculture so as to mimic the natural forest conditions, managing mixed stands of Chinese fir and broadleaf trees or conducting crop rotation of conifers and broadleaf trees as well as minimizing forest disturbances like clear-cutting, slash burning and soil preparing, could be utilized.展开更多
Soil properties were investigated in sites where three succeeding generationsof Chinese fir (Gunning-hamia lanceolata, (Lambert) Hooker) in Nanping, Fujian, China, werecultivated in order to show the impact of a repea...Soil properties were investigated in sites where three succeeding generationsof Chinese fir (Gunning-hamia lanceolata, (Lambert) Hooker) in Nanping, Fujian, China, werecultivated in order to show the impact of a repeated monoculture on site productivity. Compared withthe first generation (FG) stand the soil structure deteriorated in the second generation (SG) andthe third generation (TG) stands. For instance, the destruction rate of the peds increased by 55%-115% in the SG and the TG stands compared to the FG stand. Soil nutrient storage and nutrientavailability also decreased in the SG and the TG stands. For surface soils of 0-20 cm, the organicmatter content, total N and P, and available N and P decreased by 3%-20% relative to those in the FGstand. For many soil parameters, the differences between the FG stand and the SG and the TG standswere statistically significant (LSD test, P < 0.05). Furthermore, with each succeeding generation ofChinese fir, the total number of soil microbes declined, the soil enzyme activity weakened, and thesoil biological activity decreased. In order to maintain sustainable site productivity, newsilvicultural practices need to be developed for management of Chinese fir plantations.展开更多
AIM: To investigate the autofluorescence spectroscopic differences in normal and adenomatous coionic tissues and to determine the optimal excitation wavelengths for subsequent study and clinical application. METHODS: ...AIM: To investigate the autofluorescence spectroscopic differences in normal and adenomatous coionic tissues and to determine the optimal excitation wavelengths for subsequent study and clinical application. METHODS: Normal and adenomatous coionic tissues were obtained from patients during surgery. A FL/FS920 combined TCSPC spectrofluorimeter and a lifetime spectrometer system were used for fluorescence measurement. Fluorescence excitation wavelengths varying from 260 to 540 nm were used to induce the autofluorescence spectra, and the corresponding emission spectra were recorded from a range starting 20 nm above the excitation wavelength and extending to 800 nm. Emission spectra were assembled into a three-dimensional fluorescence spectroscopy and an excitation-emission matrix (EEM) to exploit endogenous fluorophores and diagnostic information. Then emission spectra of normal and adenomatous coionic tissues at certain excitation wavelengths were compared to determine the optimal excitation wavelengths for diagnosis of coionic cancer. RESULTS: When compared to normal tissues, low NAD (P)H and FAD, but high amino acids and endogenous phorphyrins of protoporphyrin IX characterized the high-grade malignant coionic tissues. The optimal excitation wavelengths for diagnosis of coionic cancer were about 340, 380, 460, and 540 nm. CONCLUSION: Significant differences in autofluorescence peaks and its intensities can be observed in normal and adenomatous coionic tissues. Autofluorescence EEMs are able to identify coionic tissues.展开更多
Calcium hydroxide with uniform diameters about 50—100 nm was firstly prepared under moderate condition by adding different kinds of hydrosoluble polymers. From the results of TEM and IR, the polymers were proved not ...Calcium hydroxide with uniform diameters about 50—100 nm was firstly prepared under moderate condition by adding different kinds of hydrosoluble polymers. From the results of TEM and IR, the polymers were proved not only to improve the agglomeration of the nanoparticles but also to be used as a template to control the formation of the special structure and the needed size of Ca(OH) 2 by changing the concentration of the polymers. The experimental results of TG-DTA indicate that the Ca(OH) 2 can absorb most of the acid gases released during the decomposition of polymers. So this kind of nano- Ca(OH) 2 can be used as a useful additive of environmental friendly plastics.展开更多
The amount of carbon returned through litterfall and its seasonal pattern were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunni...The amount of carbon returned through litterfall and its seasonal pattern were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata) (CF) in Sanming, Fujian Province, China. Mean annual carbon return through total litterfall over 3 years (from 1999 to 2001) was 5.097 t穐m2 in the NF, 4.337 t穐m2 in the CK and 2.502 t穐m2 in the CF respectively. Of the total carbon return in the three forests, leaf contribution accounted for 58.96%, 68.53% and 56.12% and twig 24.41%, 22.34% and 26.18%, respectively. The seasonal patterns of carbon return from total litterfall and leaf-litter were quite similar among the three forests. A peak of carbon input from litterfall in the NF and the CK occurred in spring except for the highest annual C return through branch litter of the NF in summer, while the CF showed the maximum C return in summer. The results of this study demonstrate that the natural forest has a greater C return through litterfall than monoculture plantations, which is beneficial to the increase of soil organic matter storage and the maintenance of soil fertility.展开更多
A hydrothermal reaction of zinc acetate with molybdenum trioxide, vanadium pentoxide, phosphorus pentoxide and 2,2?-bpy (2,2?-bipyridine) led to the title compound [Zn(2,2?- bpy)2(H2O)]2[HPMo12O40(VO)2] 1. Single-cr...A hydrothermal reaction of zinc acetate with molybdenum trioxide, vanadium pentoxide, phosphorus pentoxide and 2,2?-bpy (2,2?-bipyridine) led to the title compound [Zn(2,2?- bpy)2(H2O)]2[HPMo12O40(VO)2] 1. Single-crystal X-ray diffraction revealed that 1 (C40H36- N8O44PV2Zn2Mo12) crystallizes in the triclinic system, space group P1 with a = 11.881(2), b = 12.468(2), c = 12.622(2) ?, α = 71.333(8), β = 74.485(4), γ = 86.896(5)o, V = 1705.8(4) ?3, Mr = 2747.64, Z = 1, Dc = 2.675 g/cm3, μ = 3.201 mm-1, F(000) = 1309, S = 1.070, the final R = 0.0697 and wR = 0.1905 for 5368 observed reflections with I > 2σ(I). Compound 1 is built on a mixed-metal bicapped [HPMo12V2O42] subunit covalently bonded to two [Zn(2,2?-bpy)2(H2O)]2+ clusters via terminal oxygen atoms of the capping V atoms. Each Zn atom is six-coordinated by four nitrogen atoms from two 2,2?-bpy ligands, one terminal oxygen atom from coordinated water mole- cule and another one from the capped {VO} unit.展开更多
The semileptonic decays of meson Bc to a P-wave charmonium state χc(3PJ) or hc(1P1)are computed.The results show that the decays are sizable so they are accessible in Tevatron and LHC,especially,with the detectors LH...The semileptonic decays of meson Bc to a P-wave charmonium state χc(3PJ) or hc(1P1)are computed.The results show that the decays are sizable so they are accessible in Tevatron and LHC,especially,with the detectors LHCB and BTeV in the foreseeable future,and of them,the one to the 1P1 charmonium state potentially offers us a novel window to see the unconfirmed hc particle.In addition,it is pointed out that since the two charmonium radiative decays χc (3P1,2)→J/ψ+γ have sizable branching ratios,the cascade decays of the concerned decays and the charmonium radiative decays may affect the result of observing Bc meson through the semileptonic decays Bc→J/ψ+l+vl substantially.展开更多
The flora and community physiognomy of degraded plantation ecosystems onpurple soil were investigated in Ninghua County of Fujian Province, China to understand therelationship between plant diversity and ecosystem pro...The flora and community physiognomy of degraded plantation ecosystems onpurple soil were investigated in Ninghua County of Fujian Province, China to understand therelationship between plant diversity and ecosystem processes.. Four different restorationcommunities (labeled as ecological restoration treatment Ⅰ, Ⅱ, Ⅲ and Ⅳ) were selected byspace-time replacement method according to the erosion intensity in degraded purple soil ecosystem.The results showed that there were totally 86 plant species belonging to 78 genera and 43 familiesin the degraded purple soil ecosystem. Of the 15 types of distribution area in spermatophyte genus,12 types were found in the purple soil ecosystem. Along restoration gradient from low to high, plantgrowth type and life form spectra became abundant more and more, and the spermatophyte genera foreach distribution area type and genera numbers for different foliage characters increased as well.It is concluded that the plant flora and physiognomy in ecological restoration process become morecomplex and diverse, indicating that the forest ecosystem on purple soil tends to be more stable.展开更多
Single and double layered MoS2-coated multiwalled carbon nanotubes (MWCNs) were successfully prepared by pyrolyzing (NH4)2MoS4-coated multiwalled carbon nanotubes in an H2 atmosphere at 900℃. MoS2-coated MWCNs would...Single and double layered MoS2-coated multiwalled carbon nanotubes (MWCNs) were successfully prepared by pyrolyzing (NH4)2MoS4-coated multiwalled carbon nanotubes in an H2 atmosphere at 900℃. MoS2-coated MWCNs would be expected to have different tribological and mechanical properties compared to MoS2, so it may have potential applications in many fields.展开更多
In this paper,we prove the Mohebi-Radjabalipour Conjecture under an ad-ditional condition,and obtain an invariant subspace theorem on subdecomposableoperators.
The precursore Zn（en）2S （en=ethylenediamine） were prepared via a solvothermal process from elemental sulfur and zinc using ethylenediamine as a solvent. Detailed characterizations of the infrared （IR） absorption...The precursore Zn（en）2S （en=ethylenediamine） were prepared via a solvothermal process from elemental sulfur and zinc using ethylenediamine as a solvent. Detailed characterizations of the infrared （IR） absorption spectrum, powder X-ray diffraction （XRD） and thermogravimetric analysis （TG） confirmed two en coordinated with Zn2+ to form a complex cation. The morphological property was also characterized by transmission electron microscopy （TEM ） and electron diffraction analysis （ED）. Phase-pure hexagonal wurtzite ZnS products were obtained by annealing the precursor in nitrogen stream at about 900 ℃. Zn（en）2S showed a nanosize of about 30 nm, and ZnS of about 60 nm. The fluorescence spectra were also studied. PL results showed that Zn（en）2S excited a fluorescence at 452 nm.展开更多
The title compound, p-ferrocenylethylbenzoate (C19H18O2Fe, Mr = 334.18), was ob- tained by arylation from ferrocene and ethyl p-aminobenzoate. The crystal belongs to monoclinic, space group P21/c with a = 7.9659(2), b...The title compound, p-ferrocenylethylbenzoate (C19H18O2Fe, Mr = 334.18), was ob- tained by arylation from ferrocene and ethyl p-aminobenzoate. The crystal belongs to monoclinic, space group P21/c with a = 7.9659(2), b = 16.3488(5), c = 12.021(0) , b = 94.150(1)? V = 1561.39(6) 3, Z = 4, Dc = 1.422 g/cm3, F(000) = 696, (MoK) = 0.970 mm-1, R = 0.0426 and wR = 0.0888. In the molecular structure the benzene ring is located at the center of the two delocalized conjugation systems.展开更多
Nanosize CdS semiconductor particles were synthesized using the solvothermal technique. The structure was characterized by means of XRD,TEM and ED techniques. PANI film was prepared by electro-chemistry method onto th...Nanosize CdS semiconductor particles were synthesized using the solvothermal technique. The structure was characterized by means of XRD,TEM and ED techniques. PANI film was prepared by electro-chemistry method onto the indium-tin oxide glass. The nanoparticles were doped on PANI film by the dipping process, and the self-assembled nanoparticles-PANI composite film was acquired. The photoelectric properties of the self-assembled film were studied by PL and Z-scan method.展开更多
The title compound, {Mn(H2O)4(VO)2(PO4)2}n 1, was synthesized by the hydro- thermal reaction of Mn(OAc)2, Na2VO3 and H3PO4 in aqueous solution and its crystal structure was determined by X-ray single-crystal analysi...The title compound, {Mn(H2O)4(VO)2(PO4)2}n 1, was synthesized by the hydro- thermal reaction of Mn(OAc)2, Na2VO3 and H3PO4 in aqueous solution and its crystal structure was determined by X-ray single-crystal analysis. Crystallographic data for 1: H4MnO14P2V2, tetragonal system, space group I4/mmm, a = 6.251(3), c = 13.410(9) ?, Mr = 446.79, V = 524.0(5) ?3, Z = 2, F(000) = 434, μ = 3.320 mm-1, Dc = 2.832 g/cm3, the final R = 0.0577 for 163 observed reflections (I > 2σ(I)). X-ray crystal structure analysis shows that the vanadium phosphorous oxide layers are further connected by MnII(H2O)4 cations to form a three-dimensional network.展开更多
文摘Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two planta- tions of Schima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO3 -N, NH4 -N and total dissolved N (TDN). DON was calculated by subtracting NO3 -N and NH4 -N from TDN. The results - + - + showed that the precipitation had a mean DOC concentration of 1.7 mg·L-1 and DON concentration of 0.13 mg·L-1. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L-1 in the SS and 10.3 and 0.19 mg·L-1 in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L-1 respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L-1 respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipita- tion tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September-November period.
基金supported by the NIH grants(R01DE12329,R01DE14044,P60DE13076)the National Science Foundation grant(IBN-9796321)the Millenium Trust Health Excellence Fund(HEF-2000-05-04)from the Louisiana Bpard of Regents
文摘Vertebrate Msx genes are unlinked,homeobox-containing genes that bear homology to the Drosophila muscle segment homeobox gene.These genes are expressed at multiple sites of tissue-tissue interactions during vertebrate embryonic development.Inductive interactions mediated by the Msx genes are essential for normal craniofacial,limb and ectodermal organ morphogenesis,and are also essential to survival in mice,as manifested by the phenotypic abnormalities shown in knockout mice and in humans.This review summarizes studies on the expression,regulation,and functional analysis of Msx genes that bear relevance to craniofacial development in humans and mice.
基金the Basic Research Program of Fujian Province (No. 2000-F-004).
文摘Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in topsoils (0-10 cm)were quantified in two 33-year-old monoculture plantations of Castanopsis kawakamii Hayata (CK) and Cunninghamia lanceolata Lamb. (Chinese fir) (CF), and compared to a neighboring relict natural C. kawakamii forest (NF), in Sanming,Fujian. Five soil samples were collected once each in January, April, July, September and November in 2000 in each forest for laboratory analysis. Over the sampling year, there were significant differences for bacteria, fungi and actinomycetes between forests and between seasons (P ＜ 0.05). The largest bacteria and fungi populations were in NF, while CF contained the greatest number of actinomycetes. There were also significant differences (P ＜ 0.05) with microbial respiration for forests and seasons. Additionally, compared with NF, urease and acid phosphatase were significantly lower (P ＜ 0.05)in CK and CF. Also, the correlations of soil hydrolysable N and available P to soil microbial and enzymatic activities were highly significant (P ＜ 0.01). Thus, to alter the traditional Chinese fir monoculture so as to mimic the natural forest conditions, managing mixed stands of Chinese fir and broadleaf trees or conducting crop rotation of conifers and broadleaf trees as well as minimizing forest disturbances like clear-cutting, slash burning and soil preparing, could be utilized.
基金Project supported by the National Natural Science Foundation of China (No. 30170770).
文摘Soil properties were investigated in sites where three succeeding generationsof Chinese fir (Gunning-hamia lanceolata, (Lambert) Hooker) in Nanping, Fujian, China, werecultivated in order to show the impact of a repeated monoculture on site productivity. Compared withthe first generation (FG) stand the soil structure deteriorated in the second generation (SG) andthe third generation (TG) stands. For instance, the destruction rate of the peds increased by 55%-115% in the SG and the TG stands compared to the FG stand. Soil nutrient storage and nutrientavailability also decreased in the SG and the TG stands. For surface soils of 0-20 cm, the organicmatter content, total N and P, and available N and P decreased by 3%-20% relative to those in the FGstand. For many soil parameters, the differences between the FG stand and the SG and the TG standswere statistically significant (LSD test, P < 0.05). Furthermore, with each succeeding generation ofChinese fir, the total number of soil microbes declined, the soil enzyme activity weakened, and thesoil biological activity decreased. In order to maintain sustainable site productivity, newsilvicultural practices need to be developed for management of Chinese fir plantations.
基金Supported by the Natural Science Foundation of Fujian Province, No. A0310018 and No. 2002F008the Scientific Research Program of Fujian Province, No. JA03041
文摘AIM: To investigate the autofluorescence spectroscopic differences in normal and adenomatous coionic tissues and to determine the optimal excitation wavelengths for subsequent study and clinical application. METHODS: Normal and adenomatous coionic tissues were obtained from patients during surgery. A FL/FS920 combined TCSPC spectrofluorimeter and a lifetime spectrometer system were used for fluorescence measurement. Fluorescence excitation wavelengths varying from 260 to 540 nm were used to induce the autofluorescence spectra, and the corresponding emission spectra were recorded from a range starting 20 nm above the excitation wavelength and extending to 800 nm. Emission spectra were assembled into a three-dimensional fluorescence spectroscopy and an excitation-emission matrix (EEM) to exploit endogenous fluorophores and diagnostic information. Then emission spectra of normal and adenomatous coionic tissues at certain excitation wavelengths were compared to determine the optimal excitation wavelengths for diagnosis of coionic cancer. RESULTS: When compared to normal tissues, low NAD (P)H and FAD, but high amino acids and endogenous phorphyrins of protoporphyrin IX characterized the high-grade malignant coionic tissues. The optimal excitation wavelengths for diagnosis of coionic cancer were about 340, 380, 460, and 540 nm. CONCLUSION: Significant differences in autofluorescence peaks and its intensities can be observed in normal and adenomatous coionic tissues. Autofluorescence EEMs are able to identify coionic tissues.
基金Supported by the NKTRDP 10 th Five- year Plan(No.2 0 0 2 BA32 3C)
文摘Calcium hydroxide with uniform diameters about 50—100 nm was firstly prepared under moderate condition by adding different kinds of hydrosoluble polymers. From the results of TEM and IR, the polymers were proved not only to improve the agglomeration of the nanoparticles but also to be used as a template to control the formation of the special structure and the needed size of Ca(OH) 2 by changing the concentration of the polymers. The experimental results of TG-DTA indicate that the Ca(OH) 2 can absorb most of the acid gases released during the decomposition of polymers. So this kind of nano- Ca(OH) 2 can be used as a useful additive of environmental friendly plastics.
基金Supported by the Teaching and Research Award Program of MOE P.R.C. (TRAPOYT) and the Key Basic Research Project of Fujian Province (2000F004)
文摘The amount of carbon returned through litterfall and its seasonal pattern were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata) (CF) in Sanming, Fujian Province, China. Mean annual carbon return through total litterfall over 3 years (from 1999 to 2001) was 5.097 t穐m2 in the NF, 4.337 t穐m2 in the CK and 2.502 t穐m2 in the CF respectively. Of the total carbon return in the three forests, leaf contribution accounted for 58.96%, 68.53% and 56.12% and twig 24.41%, 22.34% and 26.18%, respectively. The seasonal patterns of carbon return from total litterfall and leaf-litter were quite similar among the three forests. A peak of carbon input from litterfall in the NF and the CK occurred in spring except for the highest annual C return through branch litter of the NF in summer, while the CF showed the maximum C return in summer. The results of this study demonstrate that the natural forest has a greater C return through litterfall than monoculture plantations, which is beneficial to the increase of soil organic matter storage and the maintenance of soil fertility.
基金Project supported by the Natural Science Foundation of Fujian Province (E0310016) the Education Committee Foundation of Fujian Province (JA02176)
文摘A hydrothermal reaction of zinc acetate with molybdenum trioxide, vanadium pentoxide, phosphorus pentoxide and 2,2?-bpy (2,2?-bipyridine) led to the title compound [Zn(2,2?- bpy)2(H2O)]2[HPMo12O40(VO)2] 1. Single-crystal X-ray diffraction revealed that 1 (C40H36- N8O44PV2Zn2Mo12) crystallizes in the triclinic system, space group P1 with a = 11.881(2), b = 12.468(2), c = 12.622(2) ?, α = 71.333(8), β = 74.485(4), γ = 86.896(5)o, V = 1705.8(4) ?3, Mr = 2747.64, Z = 1, Dc = 2.675 g/cm3, μ = 3.201 mm-1, F(000) = 1309, S = 1.070, the final R = 0.0697 and wR = 0.1905 for 5368 observed reflections with I > 2σ(I). Compound 1 is built on a mixed-metal bicapped [HPMo12V2O42] subunit covalently bonded to two [Zn(2,2?-bpy)2(H2O)]2+ clusters via terminal oxygen atoms of the capping V atoms. Each Zn atom is six-coordinated by four nitrogen atoms from two 2,2?-bpy ligands, one terminal oxygen atom from coordinated water mole- cule and another one from the capped {VO} unit.
文摘The semileptonic decays of meson Bc to a P-wave charmonium state χc(3PJ) or hc(1P1)are computed.The results show that the decays are sizable so they are accessible in Tevatron and LHC,especially,with the detectors LHCB and BTeV in the foreseeable future,and of them,the one to the 1P1 charmonium state potentially offers us a novel window to see the unconfirmed hc particle.In addition,it is pointed out that since the two charmonium radiative decays χc (3P1,2)→J/ψ+γ have sizable branching ratios,the cascade decays of the concerned decays and the charmonium radiative decays may affect the result of observing Bc meson through the semileptonic decays Bc→J/ψ+l+vl substantially.
基金This project was supported by Innovation Research Project of Chinese Academy of Sciences (KZCX3-SW-418)
文摘The flora and community physiognomy of degraded plantation ecosystems onpurple soil were investigated in Ninghua County of Fujian Province, China to understand therelationship between plant diversity and ecosystem processes.. Four different restorationcommunities (labeled as ecological restoration treatment Ⅰ, Ⅱ, Ⅲ and Ⅳ) were selected byspace-time replacement method according to the erosion intensity in degraded purple soil ecosystem.The results showed that there were totally 86 plant species belonging to 78 genera and 43 familiesin the degraded purple soil ecosystem. Of the 15 types of distribution area in spermatophyte genus,12 types were found in the purple soil ecosystem. Along restoration gradient from low to high, plantgrowth type and life form spectra became abundant more and more, and the spermatophyte genera foreach distribution area type and genera numbers for different foliage characters increased as well.It is concluded that the plant flora and physiognomy in ecological restoration process become morecomplex and diverse, indicating that the forest ecosystem on purple soil tends to be more stable.
文摘Single and double layered MoS2-coated multiwalled carbon nanotubes (MWCNs) were successfully prepared by pyrolyzing (NH4)2MoS4-coated multiwalled carbon nanotubes in an H2 atmosphere at 900℃. MoS2-coated MWCNs would be expected to have different tribological and mechanical properties compared to MoS2, so it may have potential applications in many fields.
文摘In this paper,we prove the Mohebi-Radjabalipour Conjecture under an ad-ditional condition,and obtain an invariant subspace theorem on subdecomposableoperators.
文摘The precursore Zn（en）2S （en=ethylenediamine） were prepared via a solvothermal process from elemental sulfur and zinc using ethylenediamine as a solvent. Detailed characterizations of the infrared （IR） absorption spectrum, powder X-ray diffraction （XRD） and thermogravimetric analysis （TG） confirmed two en coordinated with Zn2+ to form a complex cation. The morphological property was also characterized by transmission electron microscopy （TEM ） and electron diffraction analysis （ED）. Phase-pure hexagonal wurtzite ZnS products were obtained by annealing the precursor in nitrogen stream at about 900 ℃. Zn（en）2S showed a nanosize of about 30 nm, and ZnS of about 60 nm. The fluorescence spectra were also studied. PL results showed that Zn（en）2S excited a fluorescence at 452 nm.
基金The work was supported by the Education Foundation (JB020101) and Test Foundation of Fujian provincial Universities
文摘The title compound, p-ferrocenylethylbenzoate (C19H18O2Fe, Mr = 334.18), was ob- tained by arylation from ferrocene and ethyl p-aminobenzoate. The crystal belongs to monoclinic, space group P21/c with a = 7.9659(2), b = 16.3488(5), c = 12.021(0) , b = 94.150(1)? V = 1561.39(6) 3, Z = 4, Dc = 1.422 g/cm3, F(000) = 696, (MoK) = 0.970 mm-1, R = 0.0426 and wR = 0.0888. In the molecular structure the benzene ring is located at the center of the two delocalized conjugation systems.
文摘Nanosize CdS semiconductor particles were synthesized using the solvothermal technique. The structure was characterized by means of XRD,TEM and ED techniques. PANI film was prepared by electro-chemistry method onto the indium-tin oxide glass. The nanoparticles were doped on PANI film by the dipping process, and the self-assembled nanoparticles-PANI composite film was acquired. The photoelectric properties of the self-assembled film were studied by PL and Z-scan method.
基金The project was supported by the 973 program of the MOST (001CB108906) the NNSFC (90206040+4 种基金 20073048) the NSF ofFujian Province 2002F015 2002J006) the State Key Lab of Structural Chemistry (030065) and the Chinese Academy of Sciences
文摘The title compound, {Mn(H2O)4(VO)2(PO4)2}n 1, was synthesized by the hydro- thermal reaction of Mn(OAc)2, Na2VO3 and H3PO4 in aqueous solution and its crystal structure was determined by X-ray single-crystal analysis. Crystallographic data for 1: H4MnO14P2V2, tetragonal system, space group I4/mmm, a = 6.251(3), c = 13.410(9) ?, Mr = 446.79, V = 524.0(5) ?3, Z = 2, F(000) = 434, μ = 3.320 mm-1, Dc = 2.832 g/cm3, the final R = 0.0577 for 163 observed reflections (I > 2σ(I)). X-ray crystal structure analysis shows that the vanadium phosphorous oxide layers are further connected by MnII(H2O)4 cations to form a three-dimensional network.
