Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study...Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study on environmental information recorded in mud areas because of complicated sedimentary environment and variable sedimentary rate, requires a fast and economical method. In this study, we investigated the potential of X-ray fluorescence core scanner （XRFS）, a fast analytical instrument for measuring the elemental concentrations of muddy sediments, and observed a significant correlation between the element concentrations of muddy sediments determined by regular X-ray fluorescence spectrometer （XRF） and XRFS, respectively. The correlations are mainly determined by excitation energy of elements, but also influenced by solubility of element ions. Furthermore, we found a striking link between A1 concentrations and marine-originated organic carbon （MOC）, a proxy of marine primary productivity. This indicates that MOC is partly controlled by sedimentary characteristics. Therefore, XRFS method has a good potential in fast analysis of a large number of muddy sediment samples, and it can also be used to calibrate MOC in ecological study of coastal seas.展开更多
2-Benzyl-5-hydroxy-4-oxopentanoic acid 1 and its enantiomers were designed,synthesized and assayed for inhibitory activity against carboxypeptidase A(CPA,EC 3.4.17.1).To verify the role of the terminal hydroxyl group ...2-Benzyl-5-hydroxy-4-oxopentanoic acid 1 and its enantiomers were designed,synthesized and assayed for inhibitory activity against carboxypeptidase A(CPA,EC 3.4.17.1).To verify the role of the terminal hydroxyl group in 1 binding to CPA,2-benzyl-5- benzyloxy-4-oxopentanoic acid 2 was also synthesized and evaluated.The inhibition constants show that both L-1 and D-1 were shown to have strong binding affinity with L-1 being more potent than its enantiomer by 165-fold.On the other hand,the inhibition constant ...展开更多
The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition st...The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition starting at -11.6GPa is found. The space group of the high-pressure new phase is proposed as Pmca. Fitting with the Birch-Murnaghan equation of state, the bulk modulus B0 and its pressure derivative B0 of the ambient pressure structure with space group of F43m are B0 = 75.4 GPa and B0 = 4.3, respectively.展开更多
We study the strength and texture of tantalum （Ta） under uniaxiM compression up to 80 GPa using an angle-dispersive radial x-ray diffraction technique together with the lattice strain theory in a diamond anvil cell ...We study the strength and texture of tantalum （Ta） under uniaxiM compression up to 80 GPa using an angle-dispersive radial x-ray diffraction technique together with the lattice strain theory in a diamond anvil cell at ambient temperature. The ratio of differential stress to shear modulus （t/G） is found to remain constant above -60GPa, indicating that the Ta starts to experience macro yield with plastic deformation at this pressure.Combined with independent constraints on the high-pressure shear modulus, we find that the Ta sample could support a differential stress of -4.67 GPa when it starts to yield with plastic deformation at -60 CPa under unlaxial compression. The differential stress in Ta ranges from 0.216 GPa to 4.67CPa with pressure increasing from 1 GPa to 60GPa and can be expressed as t=0.199（33）＋0.075（1）P, where P is the pressure in GPa. A maximum differential stress as high as -5.37 GPa can be supported by Ta at the high pressure of -80 GPa. In addition, we investigate the texture of Ta under nonhydrostatic compression to 80 GPa using the software package material analysis using diffraction. It is proven that the plastic deformation due to stress under high pressures is responsible for the development of texture.展开更多
Free radical polymerized palladium polyacrylate was characterized by X-ray diffraction. Various parameters including mean crystallite size, interchain separation and radius of gyration have been calculated and discuss...Free radical polymerized palladium polyacrylate was characterized by X-ray diffraction. Various parameters including mean crystallite size, interchain separation and radius of gyration have been calculated and discussed with respect to the concentration of Pd in the polymeric salt. The results show that polymer is predominantly amorphous in nature.展开更多
A number of X-ray patterns and electrical conductivities of five different samples of Ag-Cu-Se system have been measured. These samples of Ag-Cu-Se system: (Ag1.188, Cu0.812)Se, (Ag,Cu)Se; (Ag0.9, Cu1.1 )Se, (Ag0.8, C...A number of X-ray patterns and electrical conductivities of five different samples of Ag-Cu-Se system have been measured. These samples of Ag-Cu-Se system: (Ag1.188, Cu0.812)Se, (Ag,Cu)Se; (Ag0.9, Cu1.1 )Se, (Ag0.8, Cu1.2)Se and (Ag0.6, Cu1.4)Se were prepared under controlled conditions. Analysis of the experimental data shows that Frenkel defects are predominated in (Ag1.188, Cu0.812)Se and Schottky defects prevailing in the other samples. The activation energy values △E calculated from the linear behaviour of electrical conductivity a with temperature (0-90℃) reveal that the impurity content increases in the direction of (Ag,Cu)Se→(Ag0.8,Cu1.2 )Se展开更多
From Wide-Angle X-ray Scattering (WAXS) pattern of uniaxially orientated fibers, the crystal structure of Nylon-1010 was determined. The Nylon-1010 crystallizes in the triclinic system, with lattice dimensions: a=4.9A...From Wide-Angle X-ray Scattering (WAXS) pattern of uniaxially orientated fibers, the crystal structure of Nylon-1010 was determined. The Nylon-1010 crystallizes in the triclinic system, with lattice dimensions: a=4.9A, b=5.4A, c=27.8, α=49 °, β=77 °,γ=63.5 °, the unit cell contains one monomeric unit and the space group is P. The degree of crystallinity of polymer was deter mined as about 60%, using Ruland's method.The structures of Nylon-1010 with different draw ratio have been investigated by using Small-Angle X-ray Scattering (SAXS). The results indicate that the draw ratio of samples has a significant effect on microstructure of Nylon-1010. The long period and thickness of amorphous layer obviously increase but the invariant, average lameUar and interphase zone show almost independent of draw ratio, long period increases because amorphous layer increases with draw ratio. The electron density fluctuation values increased with draw ratio, but inner surface O_s is drecreased.展开更多
The structures of Nylon-1010 with different draw ratios have been investigated by using Small-Angle X-ray Scattering(SAXS).It is shown that by using a simple geometrical construction the following structure parameters...The structures of Nylon-1010 with different draw ratios have been investigated by using Small-Angle X-ray Scattering(SAXS).It is shown that by using a simple geometrical construction the following structure parameters can be directly derived from the correlation function,the long period(L),the thickness of the crystal amorphous interphase(dtr),the lamellar thickness(do),the“invariant”(Q),the specific inner surface(Os), and the electron density difference between the core of the crystallites and the amorphous matrix(η_ε-η_ω)。展开更多
In the majority of rice producing countries, much of the husk produced from the processing of rice is either burnt or dumped as waste. Rice husks are one of the largest readily available but most under-utilized biomas...In the majority of rice producing countries, much of the husk produced from the processing of rice is either burnt or dumped as waste. Rice husks are one of the largest readily available but most under-utilized biomass resources, being an ideal fuel for electricity generation. In this communication the author reported the X-ray diffraction studies on rice husk ash (RHA) concrete samples heated at 300℃ and 1000℃ which were compared and observed that at 300℃ the inner surface of the specimen shows an extra compound. Copper Iron Lead Telluride Cu3FePbTe4 along with SiO2, Al5Fe2ZnO4 was present on the surface which also and might be responsible for imparting additional strength to 7.5% RHA concrete at 300℃. The X-ray diffraction studies of samples exposed to 1000℃ on temperature showed that the additional chemical compounds formed at lower temperatures were not found at 1000℃ at outer and inner surfaces of the sample indicating its possible reason for exhibiting poor strengths for all specimens. The outer surface of the 1000℃ heated specimen showed a compound named dichloroglyoxime C2H2Cl2N2O2 along with SiO2 but the inner surface of the same sample showed SiO2 alone.展开更多
Chemically synthesized ZnS thin film is found to be a good x-ray radiation sensor. We report the effect of annealing on the x-ray radiation detection sensitivity of a ZnS thin film synthesized by a chemical bath depos...Chemically synthesized ZnS thin film is found to be a good x-ray radiation sensor. We report the effect of annealing on the x-ray radiation detection sensitivity of a ZnS thin film synthesized by a chemical bath deposition technique. The chemically synthesized ZnS films are annealed at 333, 363 and 393K for 1 h. Structural analyses show that the lattice defects in the films decrease with annealing. Further, the band gap is also found to decrease from 3.38 to 3.21 eV after annealing at 393K. Current-voltage characteristics of the films are studied under dark and x-ray irradiation conditions. Due to the decrease of lattice defects and band gap, the conductivity under dark conditions is found to increase from 2.06 × 10^-6 to 1.69 × 10^-5 S/em, while that under x-ray irradiation increases from 4.13 × 10^-5 to 5.28 ×10^-5 S/cm. On the other hand, the x-ray radiation detection sensitivity of the films is found to decrease with annealing. This decrease of detection sensitivity is attributed to the decrease of the band gap as well as some structural and surface morphological changes occurring after annealing.展开更多
INTRODUCTIONThe studies on the quantitative distribution of the conventional elements and their phases in the sediments of the Changjiang Estuary are of great importance to the understanding of the chemical processes ...INTRODUCTIONThe studies on the quantitative distribution of the conventional elements and their phases in the sediments of the Changjiang Estuary are of great importance to the understanding of the chemical processes of ion exchange, absorption, desorption and flocculation in the estuary.展开更多
All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes ont...All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes onto the black hole,allowing it to grow,and its structure and evolution has been the subject of intense study in the past decade.In a recent issue of Nature Astronomy,the Chinese Academy of Sciences South America Center展开更多
N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR...N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.展开更多
A new silver complex salt [Ag(N2C11H10)2]NO3 (where N2C11H10 = 4,5-dihydro-1H-benzo[g]indazole), has been synthesized and characterized by elemental and thermal analyses, IR and 1HNMR spectroscopies, single crystal X-...A new silver complex salt [Ag(N2C11H10)2]NO3 (where N2C11H10 = 4,5-dihydro-1H-benzo[g]indazole), has been synthesized and characterized by elemental and thermal analyses, IR and 1HNMR spectroscopies, single crystal X-ray structure determination and DFT studies. Its molecular structure comprises of a silver center coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole molecule giving rise to a cationic complex entity, [Ag(N2C11H10)2]+ with as counter ion. The bulk structure is consolidated by N–H…O, C–H…π, Ag…π and Ag…O intermolecular interactions, thus generating a pseudo-helical network. The optimized structure, frontier molecular orbitals (HOMO and LUMO) and global reactivity descriptors were investigated by performing DFT calculations.展开更多
Terms of synthesis were defined for the creation of new generation chelate fertilizers and for their experimental testing. Glutamine acid and citric acid containing chelate citrates of the general formulae M.gI.HL＇nH...Terms of synthesis were defined for the creation of new generation chelate fertilizers and for their experimental testing. Glutamine acid and citric acid containing chelate citrates of the general formulae M.gI.HL＇nHO were synthesized, where, M = Mn, Zn, Fe, Co, Cu; n = 0; 1; 1.5; gl-glutamine acid; HL-citric acid anion. Identity and composition of synthesized compounds were determined by microelemental analysis, melting temperature and X-ray diffraction analysis. X-ray diffraction analysis of the compounds and glutamine acid and citric acid （H4L） was used to determine their crystalline structure and roentgen-amorphous and iso-structural orders. Their solubility was studied in various solvents.展开更多
Two new tris-chelate-complexes have been synthesized and characterized with elemental and spectroscopic methods. IR and thermal studies correlate with the structures of the complex in the solid state. The structure of...Two new tris-chelate-complexes have been synthesized and characterized with elemental and spectroscopic methods. IR and thermal studies correlate with the structures of the complex in the solid state. The structure of [Cu(en)(phen)2] was determined with X-ray data using single crystal X-ray diffractometer while the molecular structure of [Cu(en) (phen)2] 2Br - 2Phen·8H2O was deduced from the used characterization methods. [Cu(en)(phen)2]· crystallizes as orthorhombic with space group Pbcn. Both complexes have distorted octahedral geometry. Microbial activities of these complexes against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptoccocus pyogeneous, Candida albicans, and Aspergillus niger were also reported.展开更多
Mn(II), Co(II), Ni(II) and Cu(II) complexes with this ligand (L) i.e. 25, 26 dioxo1,6,12,17,23,24 hexaazacyclohexacosa1,5,12,16 tetraene have been prepared. All the complexes were characterized by elemental analysis, ...Mn(II), Co(II), Ni(II) and Cu(II) complexes with this ligand (L) i.e. 25, 26 dioxo1,6,12,17,23,24 hexaazacyclohexacosa1,5,12,16 tetraene have been prepared. All the complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, i.r. electronic, and e.p.r. spectral studies. The molar conductance measurements in DMF indicate that the Mn(II), Co(II), and Cu(II) are non-electrolyte whereas the complexes of Ni(II) are electrolyte. Thus, these complexes may by formulated as [M(L)X2] and [Ni(L)]X2 (where M = Mn(II), Co(II) and Cu(II) and X = C1- and ). All the complexes are of the high spin type expected Ni(II) complexes which are diamagnetic. On the basis of spectral studies, an octahedral geometry may be assigned of Mn(II) and Co(II). Square planar is for Ni(II) complexes, and tetragonal geometry for Cu(II) complexes.展开更多
BACKGROUND X-ray gastric cancer(GC)screening has been shown to decrease mortality.Population-based X-ray GC screening has been performed in Hiroshima Prefe-cture,Japan,since 1983 but time trends and the efficacy of th...BACKGROUND X-ray gastric cancer(GC)screening has been shown to decrease mortality.Population-based X-ray GC screening has been performed in Hiroshima Prefe-cture,Japan,since 1983 but time trends and the efficacy of the method over 39 years have not been assessed.METHODS This was a population-based retrospective study.The data were derived from aggregated data of the Hiroshima Regional Health Medical Promotion Organization,including the number and rate of participants and those requiring esophagogastroduodenoscopies(EGDs),the number and rate of participants diagnosed as having GC,and the positive predictive value of the abnormal findings detected by X-ray and confirmed by EGDs.The number and rate of esophageal cancers were also collected.Further,the cost of detecting one GC was evaluated.RESULTS The number of participants has decreased during the last four decades,from 39925 in 1983 to 12923 in 2021.The rate of those requiring EGDs decreased significantly in recent years(P<0.001).The number of participants diagnosed as having GC has also declined,from 76 to 10 cases.However,the rate of cases diagnosed as GC among the participants remained around 0.1%.The positive predictive value increased significantly in recent years except during 1983-1991.The number and rate of accidentally detected esophageal cancers have risen recently,from 0%in 2008 to 0.02%in 2021,one-fifth of the diagnosis rate of GC.One GC diagnosis costs approximately 4200000 Japanese Yen(30000 United States Dollars)for the X-ray screenings and EGDs.CONCLUSION X-ray GC screening in Hiroshima has been efficient,but one challenge is the cost.Esophageal cancers may also need to be considered because they have gradually increased in recent years.展开更多
Lanthanum malonate crystals were grown by single tube ionic diffusion through silica gel. The crystallinity of the grown crystals was analyzed by powder X-ray diffraction studies. Fourier transform infrared spectrosco...Lanthanum malonate crystals were grown by single tube ionic diffusion through silica gel. The crystallinity of the grown crystals was analyzed by powder X-ray diffraction studies. Fourier transform infrared spectroscopy （FTIR） and fourier transform （FT） Raman studies confirmed the presence of functional groups in the title compound. The optical band gap energy of the material was extracted from diffuse reflectance spectrum.展开更多
The optically transparent and bulk single crystal of p-Toluidine p-Toluenesulfonate (PTPT) was grown by slow evaporation technique. The lattice parameters and crystallinity of the grown crystal were estimated by singl...The optically transparent and bulk single crystal of p-Toluidine p-Toluenesulfonate (PTPT) was grown by slow evaporation technique. The lattice parameters and crystallinity of the grown crystal were estimated by single crystal XRD. The optical absorption of the crystal was recorded using the UV-Vis-NIR spectrophotometer. The optical bandgap and optical constants of the material were determined by using absorption spectrum. The refractive index of the grown crystal has been determined using the Brewster angle method. The dielectric constant and dielectric loss were measured as a function of frequency and temperature for the grown crystal. Nonlinear optical properties were performed to confirm the SHG efficiency of the grown crystal. Hence, PTPT is an excellent NLO material with enhanced SHG efficiency required for important applications in the field of optoelectronic and photonics. This material exhibits NLO behaviour remarkably due to its better optical and dielectric properties.展开更多
基金supported by the National Basic Research Program of China(2010CB428902)National Natural Science Foundation of China(40876088)
文摘Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study on environmental information recorded in mud areas because of complicated sedimentary environment and variable sedimentary rate, requires a fast and economical method. In this study, we investigated the potential of X-ray fluorescence core scanner （XRFS）, a fast analytical instrument for measuring the elemental concentrations of muddy sediments, and observed a significant correlation between the element concentrations of muddy sediments determined by regular X-ray fluorescence spectrometer （XRF） and XRFS, respectively. The correlations are mainly determined by excitation energy of elements, but also influenced by solubility of element ions. Furthermore, we found a striking link between A1 concentrations and marine-originated organic carbon （MOC）, a proxy of marine primary productivity. This indicates that MOC is partly controlled by sedimentary characteristics. Therefore, XRFS method has a good potential in fast analysis of a large number of muddy sediment samples, and it can also be used to calibrate MOC in ecological study of coastal seas.
文摘2-Benzyl-5-hydroxy-4-oxopentanoic acid 1 and its enantiomers were designed,synthesized and assayed for inhibitory activity against carboxypeptidase A(CPA,EC 3.4.17.1).To verify the role of the terminal hydroxyl group in 1 binding to CPA,2-benzyl-5- benzyloxy-4-oxopentanoic acid 2 was also synthesized and evaluated.The inhibition constants show that both L-1 and D-1 were shown to have strong binding affinity with L-1 being more potent than its enantiomer by 165-fold.On the other hand,the inhibition constant ...
基金Supported by the National Natural Science Foundation and the Ministry of Science and Technology of Chinathe National Natural Science Foundation of China under Grant No U1530402+3 种基金the U.S. Department of Energy of Office of Science under Grant No DE-AC02-06CH11357the DOE-NNSA under Grant No DE-NA0001974the DOE-BES under Grant No DE-FG02-99ER45775the Instrumentation Funding of National Science Foundation
文摘The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition starting at -11.6GPa is found. The space group of the high-pressure new phase is proposed as Pmca. Fitting with the Birch-Murnaghan equation of state, the bulk modulus B0 and its pressure derivative B0 of the ambient pressure structure with space group of F43m are B0 = 75.4 GPa and B0 = 4.3, respectively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10875142 and 11079040the Chinese Academy of Sciences under Grant Nos KJCX2-SW-N03 and KJCX2-SW-N20
文摘We study the strength and texture of tantalum （Ta） under uniaxiM compression up to 80 GPa using an angle-dispersive radial x-ray diffraction technique together with the lattice strain theory in a diamond anvil cell at ambient temperature. The ratio of differential stress to shear modulus （t/G） is found to remain constant above -60GPa, indicating that the Ta starts to experience macro yield with plastic deformation at this pressure.Combined with independent constraints on the high-pressure shear modulus, we find that the Ta sample could support a differential stress of -4.67 GPa when it starts to yield with plastic deformation at -60 CPa under unlaxial compression. The differential stress in Ta ranges from 0.216 GPa to 4.67CPa with pressure increasing from 1 GPa to 60GPa and can be expressed as t=0.199（33）＋0.075（1）P, where P is the pressure in GPa. A maximum differential stress as high as -5.37 GPa can be supported by Ta at the high pressure of -80 GPa. In addition, we investigate the texture of Ta under nonhydrostatic compression to 80 GPa using the software package material analysis using diffraction. It is proven that the plastic deformation due to stress under high pressures is responsible for the development of texture.
文摘Free radical polymerized palladium polyacrylate was characterized by X-ray diffraction. Various parameters including mean crystallite size, interchain separation and radius of gyration have been calculated and discussed with respect to the concentration of Pd in the polymeric salt. The results show that polymer is predominantly amorphous in nature.
文摘A number of X-ray patterns and electrical conductivities of five different samples of Ag-Cu-Se system have been measured. These samples of Ag-Cu-Se system: (Ag1.188, Cu0.812)Se, (Ag,Cu)Se; (Ag0.9, Cu1.1 )Se, (Ag0.8, Cu1.2)Se and (Ag0.6, Cu1.4)Se were prepared under controlled conditions. Analysis of the experimental data shows that Frenkel defects are predominated in (Ag1.188, Cu0.812)Se and Schottky defects prevailing in the other samples. The activation energy values △E calculated from the linear behaviour of electrical conductivity a with temperature (0-90℃) reveal that the impurity content increases in the direction of (Ag,Cu)Se→(Ag0.8,Cu1.2 )Se
文摘From Wide-Angle X-ray Scattering (WAXS) pattern of uniaxially orientated fibers, the crystal structure of Nylon-1010 was determined. The Nylon-1010 crystallizes in the triclinic system, with lattice dimensions: a=4.9A, b=5.4A, c=27.8, α=49 °, β=77 °,γ=63.5 °, the unit cell contains one monomeric unit and the space group is P. The degree of crystallinity of polymer was deter mined as about 60%, using Ruland's method.The structures of Nylon-1010 with different draw ratio have been investigated by using Small-Angle X-ray Scattering (SAXS). The results indicate that the draw ratio of samples has a significant effect on microstructure of Nylon-1010. The long period and thickness of amorphous layer obviously increase but the invariant, average lameUar and interphase zone show almost independent of draw ratio, long period increases because amorphous layer increases with draw ratio. The electron density fluctuation values increased with draw ratio, but inner surface O_s is drecreased.
文摘The structures of Nylon-1010 with different draw ratios have been investigated by using Small-Angle X-ray Scattering(SAXS).It is shown that by using a simple geometrical construction the following structure parameters can be directly derived from the correlation function,the long period(L),the thickness of the crystal amorphous interphase(dtr),the lamellar thickness(do),the“invariant”(Q),the specific inner surface(Os), and the electron density difference between the core of the crystallites and the amorphous matrix(η_ε-η_ω)。
文摘In the majority of rice producing countries, much of the husk produced from the processing of rice is either burnt or dumped as waste. Rice husks are one of the largest readily available but most under-utilized biomass resources, being an ideal fuel for electricity generation. In this communication the author reported the X-ray diffraction studies on rice husk ash (RHA) concrete samples heated at 300℃ and 1000℃ which were compared and observed that at 300℃ the inner surface of the specimen shows an extra compound. Copper Iron Lead Telluride Cu3FePbTe4 along with SiO2, Al5Fe2ZnO4 was present on the surface which also and might be responsible for imparting additional strength to 7.5% RHA concrete at 300℃. The X-ray diffraction studies of samples exposed to 1000℃ on temperature showed that the additional chemical compounds formed at lower temperatures were not found at 1000℃ at outer and inner surfaces of the sample indicating its possible reason for exhibiting poor strengths for all specimens. The outer surface of the 1000℃ heated specimen showed a compound named dichloroglyoxime C2H2Cl2N2O2 along with SiO2 but the inner surface of the same sample showed SiO2 alone.
文摘Chemically synthesized ZnS thin film is found to be a good x-ray radiation sensor. We report the effect of annealing on the x-ray radiation detection sensitivity of a ZnS thin film synthesized by a chemical bath deposition technique. The chemically synthesized ZnS films are annealed at 333, 363 and 393K for 1 h. Structural analyses show that the lattice defects in the films decrease with annealing. Further, the band gap is also found to decrease from 3.38 to 3.21 eV after annealing at 393K. Current-voltage characteristics of the films are studied under dark and x-ray irradiation conditions. Due to the decrease of lattice defects and band gap, the conductivity under dark conditions is found to increase from 2.06 × 10^-6 to 1.69 × 10^-5 S/em, while that under x-ray irradiation increases from 4.13 × 10^-5 to 5.28 ×10^-5 S/cm. On the other hand, the x-ray radiation detection sensitivity of the films is found to decrease with annealing. This decrease of detection sensitivity is attributed to the decrease of the band gap as well as some structural and surface morphological changes occurring after annealing.
基金The project was supported by the National Natural Science Foundation of China.
文摘INTRODUCTIONThe studies on the quantitative distribution of the conventional elements and their phases in the sediments of the Changjiang Estuary are of great importance to the understanding of the chemical processes of ion exchange, absorption, desorption and flocculation in the estuary.
文摘All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes onto the black hole,allowing it to grow,and its structure and evolution has been the subject of intense study in the past decade.In a recent issue of Nature Astronomy,the Chinese Academy of Sciences South America Center
基金the Ministry of Higher Education of Malaysia and Universiti Kebangsaan Malaysia for the research grant DIP-2014-016 and FRGS/1/2013/ST01/UKM/03/4the Ministry of Higher Education of Libya for the scholarship
文摘N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.
文摘A new silver complex salt [Ag(N2C11H10)2]NO3 (where N2C11H10 = 4,5-dihydro-1H-benzo[g]indazole), has been synthesized and characterized by elemental and thermal analyses, IR and 1HNMR spectroscopies, single crystal X-ray structure determination and DFT studies. Its molecular structure comprises of a silver center coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole molecule giving rise to a cationic complex entity, [Ag(N2C11H10)2]+ with as counter ion. The bulk structure is consolidated by N–H…O, C–H…π, Ag…π and Ag…O intermolecular interactions, thus generating a pseudo-helical network. The optimized structure, frontier molecular orbitals (HOMO and LUMO) and global reactivity descriptors were investigated by performing DFT calculations.
基金We thank Science ＆ Technology Center in Ukraine and Shota Rustaveli National Science Foundation. The work was implemented with the support of Science ＆ Technology Center in Ukraine Project Proposal #5461 and Shota Rustaveli National Science Foundation Grant #30/06.
文摘Terms of synthesis were defined for the creation of new generation chelate fertilizers and for their experimental testing. Glutamine acid and citric acid containing chelate citrates of the general formulae M.gI.HL＇nHO were synthesized, where, M = Mn, Zn, Fe, Co, Cu; n = 0; 1; 1.5; gl-glutamine acid; HL-citric acid anion. Identity and composition of synthesized compounds were determined by microelemental analysis, melting temperature and X-ray diffraction analysis. X-ray diffraction analysis of the compounds and glutamine acid and citric acid （H4L） was used to determine their crystalline structure and roentgen-amorphous and iso-structural orders. Their solubility was studied in various solvents.
文摘Two new tris-chelate-complexes have been synthesized and characterized with elemental and spectroscopic methods. IR and thermal studies correlate with the structures of the complex in the solid state. The structure of [Cu(en)(phen)2] was determined with X-ray data using single crystal X-ray diffractometer while the molecular structure of [Cu(en) (phen)2] 2Br - 2Phen·8H2O was deduced from the used characterization methods. [Cu(en)(phen)2]· crystallizes as orthorhombic with space group Pbcn. Both complexes have distorted octahedral geometry. Microbial activities of these complexes against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptoccocus pyogeneous, Candida albicans, and Aspergillus niger were also reported.
文摘Mn(II), Co(II), Ni(II) and Cu(II) complexes with this ligand (L) i.e. 25, 26 dioxo1,6,12,17,23,24 hexaazacyclohexacosa1,5,12,16 tetraene have been prepared. All the complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, i.r. electronic, and e.p.r. spectral studies. The molar conductance measurements in DMF indicate that the Mn(II), Co(II), and Cu(II) are non-electrolyte whereas the complexes of Ni(II) are electrolyte. Thus, these complexes may by formulated as [M(L)X2] and [Ni(L)]X2 (where M = Mn(II), Co(II) and Cu(II) and X = C1- and ). All the complexes are of the high spin type expected Ni(II) complexes which are diamagnetic. On the basis of spectral studies, an octahedral geometry may be assigned of Mn(II) and Co(II). Square planar is for Ni(II) complexes, and tetragonal geometry for Cu(II) complexes.
文摘BACKGROUND X-ray gastric cancer(GC)screening has been shown to decrease mortality.Population-based X-ray GC screening has been performed in Hiroshima Prefe-cture,Japan,since 1983 but time trends and the efficacy of the method over 39 years have not been assessed.METHODS This was a population-based retrospective study.The data were derived from aggregated data of the Hiroshima Regional Health Medical Promotion Organization,including the number and rate of participants and those requiring esophagogastroduodenoscopies(EGDs),the number and rate of participants diagnosed as having GC,and the positive predictive value of the abnormal findings detected by X-ray and confirmed by EGDs.The number and rate of esophageal cancers were also collected.Further,the cost of detecting one GC was evaluated.RESULTS The number of participants has decreased during the last four decades,from 39925 in 1983 to 12923 in 2021.The rate of those requiring EGDs decreased significantly in recent years(P<0.001).The number of participants diagnosed as having GC has also declined,from 76 to 10 cases.However,the rate of cases diagnosed as GC among the participants remained around 0.1%.The positive predictive value increased significantly in recent years except during 1983-1991.The number and rate of accidentally detected esophageal cancers have risen recently,from 0%in 2008 to 0.02%in 2021,one-fifth of the diagnosis rate of GC.One GC diagnosis costs approximately 4200000 Japanese Yen(30000 United States Dollars)for the X-ray screenings and EGDs.CONCLUSION X-ray GC screening in Hiroshima has been efficient,but one challenge is the cost.Esophageal cancers may also need to be considered because they have gradually increased in recent years.
文摘Lanthanum malonate crystals were grown by single tube ionic diffusion through silica gel. The crystallinity of the grown crystals was analyzed by powder X-ray diffraction studies. Fourier transform infrared spectroscopy （FTIR） and fourier transform （FT） Raman studies confirmed the presence of functional groups in the title compound. The optical band gap energy of the material was extracted from diffuse reflectance spectrum.
文摘The optically transparent and bulk single crystal of p-Toluidine p-Toluenesulfonate (PTPT) was grown by slow evaporation technique. The lattice parameters and crystallinity of the grown crystal were estimated by single crystal XRD. The optical absorption of the crystal was recorded using the UV-Vis-NIR spectrophotometer. The optical bandgap and optical constants of the material were determined by using absorption spectrum. The refractive index of the grown crystal has been determined using the Brewster angle method. The dielectric constant and dielectric loss were measured as a function of frequency and temperature for the grown crystal. Nonlinear optical properties were performed to confirm the SHG efficiency of the grown crystal. Hence, PTPT is an excellent NLO material with enhanced SHG efficiency required for important applications in the field of optoelectronic and photonics. This material exhibits NLO behaviour remarkably due to its better optical and dielectric properties.
