Absolute light utilization efficiency across leaf section of Euonymus japonicus T. was calculated based on the measurements of photoacoustic technique (PA technique) and microscopic fiber optic probe. This new method ...Absolute light utilization efficiency across leaf section of Euonymus japonicus T. was calculated based on the measurements of photoacoustic technique (PA technique) and microscopic fiber optic probe. This new method was based on the principal of depth analysis by PA technique and the differential analysis of light gradients across leaf section by micro-optical probe technique. The depth analysis was shown by a sample of PA scan light absorption spectra. Results showed that the tissue layers between palisade tissue and spongy tissue used the smallest proportion of incident light energy for photochemical reactions (about 0.026% incident light energy of 660 nm light), while in tissue layer more close to the adaxial surface of leaf or the abaxial surface of leaf, the efficiency of utilization of light energy tended to be improved, e. g. 0.092% for tissue layers close to adaxial surface; 0.036% for tissue layers close to abaxial surface. The results that different leaf tissue layers utilized different proportion of incident light energy for photochemical reaction directly prove the hypothesis put forward by Han and Vogelmann.展开更多
The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results sh...The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results show that Se in burdock stem, skin and leaf are 32.40, 48.63, 38.10 μg/g, respectively; Cd in burdock stem, skin and leaf are 0. 160 0, 0. 300 0, 0. 140 0 μg/g, respectively; Cd in burdock stem, skin and leaf are 2. 020, 3. 960, 2. 410 μg/g, respectively. In the ginkgo and ginko leaf, Se contents are 17.63 and 16.91 μg/g, respectively ; for Cd are 0. 181 0 and 0.2020μg/g, respectively ; for Pb are 3. 572 and 4. 021 μg/g, respectively. In garlic, Se, Cd and Pb are 73. 900 0, 6. 900 0 and 0. 390 0, respectively. All the standard deviations of measured results are below 2.3%, recovery rate are from 99% to 101%.展开更多
In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 ...In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 and H2O2, and detected by the standard curve method. The results showed that Guoshangye contained abundant trace elements which rates of these trace elements were in the curacy and satisfactory. were necessary for human. The recovery range of 96%-103%. The method is ac-展开更多
[Objective] This study aimed to identify red pigment of Panax notoginseng fruits and explore the correlation between pigment content and total saponins of the fruits. [Method] The red pigment of Panax notoginseng frui...[Objective] This study aimed to identify red pigment of Panax notoginseng fruits and explore the correlation between pigment content and total saponins of the fruits. [Method] The red pigment of Panax notoginseng fruits was preliminarily identi- fied with specific color reactions and UV-vis spectra, and the contents of the pigment and total saponins were determined via spectrophotometry. [Result] The red hues of the fruits were contributed by anthocyanins and/or the anthocyanidins. The contents of anthocyanins and total saponins of the fruits both decreased along with thinning of the red hues. The content difference of the anthocyanins in fruits with different red hues reached extremely significant level, but that of total saponins just reached significant level. [Conclusion] The red pigment of P. notoginseng fruits is anthocyanins which are of extremely significant positive correlation with total saponins in contents.展开更多
Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is int...Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography (CT) method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions.展开更多
The liquid ion exchange method, solid salt melt method and dry-wet circulation method were used to prepare natural porous antimicrobial materials with natural minerals, such as zeolite, spilite, palygorskite and montm...The liquid ion exchange method, solid salt melt method and dry-wet circulation method were used to prepare natural porous antimicrobial materials with natural minerals, such as zeolite, spilite, palygorskite and montmorillonite, respectively. Atomic absorption spectrum and X-ray diffraction analysis were carried out to investigate the effects of Ag^+ , Cu^2+ and Zn^2+ on antimicrobial abilities of natural porous minerals, and the effect of preparation method on ion exchange capacity of antimicrobial material, respectively. The results show that for the ion exchange capacity, clay mineral is higher than fibrous mineral, i.e. both zeolite and montmorillonite are higher; the antimicrobial ability of material with Ag^+ is the bests the exchange capacities of materials with Cu^2+ or Zn^2+ are all higher, but the antimicrobial ability of Cu^2+ is better than that of Zn^2+ .展开更多
Eleven nutrition elements and 5 quality elements of garlic (Allium sativum L.) in different Se, S level and their interaction pot experiments were analyzed by atom absorbing spectrophotometer, titration and fixing s...Eleven nutrition elements and 5 quality elements of garlic (Allium sativum L.) in different Se, S level and their interaction pot experiments were analyzed by atom absorbing spectrophotometer, titration and fixing sulfur method. The mineral elements were analyzed by the Principal Component Analysis and the Factor Analysis on the SPSS 10.0 and three main factors were picked. The results showed that Se, S and Se-S cooperated application enhanced the garlic nutrition quality by increasing mineral nutrition. The garlic Vc was the highest after using higher Se compared middle S level (S 20 mg/kg soil + Se 40 mg/kg soil). Lower Se level compared middle S level (S 40 mg/kg soil + Se 20 mg/kg soil) get the highest garlic abio-Se in all treatments. The garlic organic Se content was the highest after using higher Se compared middle S (S 40 mg/kg soil + Se 40 mg/kg soil). The treatment lower S compared lower Se level get the highest garlic allicin in all treatment. It showed that the fresh eating factor was affected by the element Se. The flavor factor and health care factor were affected by both Se and S.展开更多
Ultraviolet-visible(UV-Vis)spectrophotometry is commonly used in analytical laboratories for qualitative and quantitative analyses.To make the data obtained reliable,an experimental instrument must be calibrated.Nat...Ultraviolet-visible(UV-Vis)spectrophotometry is commonly used in analytical laboratories for qualitative and quantitative analyses.To make the data obtained reliable,an experimental instrument must be calibrated.National Institute for Standards(NIS)in Egypt builds up aphotometric method to ensure the competence of absorbance and transmittance to the standard international and national requirements.This paper presents an instrument for UV-Vis measurement,discusses the factors affecting measurement reliability and estabishes the uncertainty model including correspoding measurement parameters.展开更多
The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its ...The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its existence. Metal ions in foodstuff are in different chemical forms, as inorganic salts or organic molecules or complexes with other compounds such as proteins, amino acids, enzymes and some vitamins, among others, that play an important role in human health. Entomophagy, insect consumption by several ethnic groups in Mexico as cultural tradition since prehispanic era represent an option for population to obtain the minerals needed by the body to keep a good health. Escamoles ant eggs of the Liometopumapiculatum M genus, much appreciated either at rural communities as well as in urban cities, contain minerals with a favorable effect in human health. The aim of this study was to investigate the mineral composition of Escamoles and the benefits which can provide to the human body. Sampling was at an arid region of the Hidalgo state on April 2012. Minerals in dry basis, determined by atomic absorption spectrophotometry, with the exception of phosphorus content, obtained from a triple acid digested extract and determined colorimetrically. Data of mineral analysis in dry basis of Escamoles were: total minerals 5.92%; Na 0.079%; K 0.075%; Ca 0.097%; P 0.701%; Fe 0.021%; Zn 0.035% Cu 0.009%; Mg 0.998%; Mn 0.002%. Minerals quantify are not equal to total ash contained because not all of them were assess determined. Elements concentration depends not only on the total mineral composition of foodstuff the inorganic or organic form or interaction among metal ions, but also on their availability and avail of them. Minerals in Escamoles ant eggs have a considerable influence in the condition of human health.展开更多
We theoretically investigate the optical absorption spectra and charge density by subjecting a GaAs quantum well to both an intense terahertz (THz)-frequency driving field and an optical pulse within the theory of den...We theoretically investigate the optical absorption spectra and charge density by subjecting a GaAs quantum well to both an intense terahertz (THz)-frequency driving field and an optical pulse within the theory of density matrix. In presence of a strong THz field, the optical transitions in quantum well subbands are altered by the THz field. The alteration has a direct impact on the optical absorption and the charge density. The excitonic peak splitting and THz optical sideband in the absorption spectra show up when changing the THz field intensity and/or frequency. The Autler-Towns splitting is a result from the THz nonlinear dynamics of confined excitons. On the other hand, the carrier charge density is created as wave packets formed by coherent superposition of several eigenstates. The charge density exhibitsquantum beats for short pulses and/or wider wells and is modulated by the THz field.展开更多
The photoabsorption spectra have been calculated for Sis and SilO (n ≤ 5) clusters using time-dependent density-function theory. Our studies suggest that Sin-1 O clusters are relatively stable than those of corresp...The photoabsorption spectra have been calculated for Sis and SilO (n ≤ 5) clusters using time-dependent density-function theory. Our studies suggest that Sin-1 O clusters are relatively stable than those of corresponding Sis clusters. Moreover, substantial differences are observed among the absorption spectra of different molecules in the energy region (0 - 8 eV). Comparing two different exchange-correlation potentials, local-density and generalized-gradient approximations, both calculated optical spectra present the same spectral feature.展开更多
On the basis of analysis on the temperature monitoring methods for high voltage devices, a new type of fiber optic sensor structure with reference channel is given. And the operation principle of fiber optic sensor is...On the basis of analysis on the temperature monitoring methods for high voltage devices, a new type of fiber optic sensor structure with reference channel is given. And the operation principle of fiber optic sensor is analysed at large based on the absorption of semiconductor chip. The mathematical model of both devices and the whole system are also given. It is proved by the experiment that this mathematical model is reliable.展开更多
Present study is carried out in the bone samples collected from Roopkund Lake in district Chamoli Garhwal, Uttarakhand which is located at 5,029 meters from main sea level in between Nanda Ghunghti and Trishuli peak. ...Present study is carried out in the bone samples collected from Roopkund Lake in district Chamoli Garhwal, Uttarakhand which is located at 5,029 meters from main sea level in between Nanda Ghunghti and Trishuli peak. This historical site belongs to 9th century A.D. All the samples selected for the study were dried in room temperature as well as hot air oven at 32 ~C. Cleaning, pretreatment and digestion process of faunal remains was followed through established scientific methods. Chemical analysis i.e. concentration of different elements such as calcium, strontium, barium, magnesium and zinc as well as isotopic ratios of Carbon and Nitrogen was estimated with the help of ICP (inductively coupled plasma spectroscopy) and AAS (atomic absorption spectrophotometer). The results obtained from the chemical analysis are significant. On the basis of concentration of different elements and ratios of Nitrogen and Carbon isotopes, the dietary habits of the peoples buried in the Roopkund Lake are identified, which is different from sample to sample person to person. Besides this, the results are also significantly helpful for knowing the preservation status of faunal remains in Roopkund Lake. Finally this study also indicated the potentiality of chemical analysis for reconstructing the palaeodiet behaviour and preservation status of bone remains.展开更多
With the frame of the time-dependent local density approximation, an efficient description of the optical response of clusters has been used to study the photo-absorption cross section of Na2 and Na4 clusters. It is s...With the frame of the time-dependent local density approximation, an efficient description of the optical response of clusters has been used to study the photo-absorption cross section of Na2 and Na4 clusters. It is shown that our calculated results are in good agreement with the experiment. In addition, our calculated spectrum for the Na4 cluster is in better agreement with experiment than the GW absorption spectrum.展开更多
The bioavailability of five divalent cationic heavy metals (Pb, Cd, Cu, Zn and Ni) in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals (SEMs...The bioavailability of five divalent cationic heavy metals (Pb, Cd, Cu, Zn and Ni) in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals (SEMs) to acid volatile sulfide (AVS). Atomic absorption spectrometry (AAS) and X-ray powder diffraction (XRD) were used to determine the heavy metal concentrations and examine the mineralogy of the crystalline phases, respectively. The AVS loadings in sediments from Baihua Lake ranged from 64.30 to 350.08 ~rnol/g (dry weight). The corresponding SEM levels for the sampling sites varied from 1.770 to 14.660 vrnol/g. The molar ratio of SEMs to AVS ranged from 0.014 to 0.084 with a mean value of 0.034. The XRD analysis also confirmed the presence of some metal sulfides in sediments from Baihua Lake. The SEMs/AVS ratios for all sampling sites were significantly lower than 1.0, indicating that AVS in the sediments was sufficient to bind the five heavy metals; thus, these heavy metals are currently not significantly bioavailable to benthic organisms. Comparing the SEMs results to published guideline values for metal toxicity to benthic organisms in sediments, however, suggests that Zn and Ni pose a risk at some sampling locations in Baihua Lake.展开更多
Based upon the standard deviations for the intercept and the slope of a linear regression line, as well as by differentiating both Beer's law and a linear relationship between transmittance and concentration at high ...Based upon the standard deviations for the intercept and the slope of a linear regression line, as well as by differentiating both Beer's law and a linear relationship between transmittance and concentration at high transmission, it is proved that the relative spectrophotometric error of a measurement becomes greater as the sample concentration only decreases. Further, it is demonstrated that the present knowledge with regard to the error in absorption spectrophotometry is necessary to be reexamined. The total scale of transmittance can literally be used for measurements, unfolding workable dynamic ranges about two orders of magnitude lower than usually and thus absorption spectrophotometry can efficiently compete with other methods of analysis with respect to detection limits.展开更多
Infrared emissivity was studied in Zno.99Mo.olO (M is Mn, Fe or Ni) and Znl_xCoxO (x=0.01, 0.02, 0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzit...Infrared emissivity was studied in Zno.99Mo.olO (M is Mn, Fe or Ni) and Znl_xCoxO (x=0.01, 0.02, 0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2+ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest (0.829) and that of Zno.99C00.010 is the lowest (0.784) at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum (0.752) at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.展开更多
2,7′-(Ethylene)-bis-8-hydroxyquinoline was optimized with DFT/B3LYP and ab initio HF methods, so ion- ization potential and electron affinity could be determined. Absorption spectrum was calculated by ZINDO and TD-...2,7′-(Ethylene)-bis-8-hydroxyquinoline was optimized with DFT/B3LYP and ab initio HF methods, so ion- ization potential and electron affinity could be determined. Absorption spectrum was calculated by ZINDO and TD-DFT. CIS method was used to calculate the S1 excited states of the compound and afterwards the emission spectrum was computed. When the solvent effect was taken into account, the computed results show encouraging agreement with known experimental data. The results of analyzing the relationship between the energies and absorption spectra indicate that the ability to transporting electrons is strengthened compared with 8-hydroxyquinoline and that absorption and emission spectra are red-shifted. The intramoleeular reor- ganization energy of tris(2,7′-(ethylene)-bis-8-hydroxyquinoline)-aluminum implies its electron transporting property is worse than tris(8-hydroxyquinoline)-aluminum. The predicted maximum emission wavelength is red-shifted compared with tris(8-hydroxyquinoline)-aluminum.展开更多
A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban (236), rural (80) a...A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban (236), rural (80) and industrial areas (97) were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer (GFAAS). Cognitive development was measured by the 'McCarthy Scales of Children's Abilities Test' (MSCA). Significant differences found in the mean cognitive scores between the urban (94.40), industrial (102.90) and suburban children (101.24) (p 〈 0.001), with the blood lead between the urban (3.66 p.g/dL), industrial (3.54 μg/dL) and suburban children (3.04μg/dL) (p = 0.022). Significant inverse correlations between blood lead and cognitive scores found for all groups (p 〈 0.001), urban (p 〈 0.001) and suburban children (p 〈 0.001). Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders (p _〈 0.001). The urban children's cognitive scores were significantly influenced by blood lead levels and household income (p 〈 0.001). However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers' education, number of siblings, sequence in the family and the household income (p 〈 0.001 ). Blood lead below 10μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development.展开更多
文摘Absolute light utilization efficiency across leaf section of Euonymus japonicus T. was calculated based on the measurements of photoacoustic technique (PA technique) and microscopic fiber optic probe. This new method was based on the principal of depth analysis by PA technique and the differential analysis of light gradients across leaf section by micro-optical probe technique. The depth analysis was shown by a sample of PA scan light absorption spectra. Results showed that the tissue layers between palisade tissue and spongy tissue used the smallest proportion of incident light energy for photochemical reactions (about 0.026% incident light energy of 660 nm light), while in tissue layer more close to the adaxial surface of leaf or the abaxial surface of leaf, the efficiency of utilization of light energy tended to be improved, e. g. 0.092% for tissue layers close to adaxial surface; 0.036% for tissue layers close to abaxial surface. The results that different leaf tissue layers utilized different proportion of incident light energy for photochemical reaction directly prove the hypothesis put forward by Han and Vogelmann.
基金School Fund of Xuzhou Institute of Technology (XKY200614)~~
文摘The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results show that Se in burdock stem, skin and leaf are 32.40, 48.63, 38.10 μg/g, respectively; Cd in burdock stem, skin and leaf are 0. 160 0, 0. 300 0, 0. 140 0 μg/g, respectively; Cd in burdock stem, skin and leaf are 2. 020, 3. 960, 2. 410 μg/g, respectively. In the ginkgo and ginko leaf, Se contents are 17.63 and 16.91 μg/g, respectively ; for Cd are 0. 181 0 and 0.2020μg/g, respectively ; for Pb are 3. 572 and 4. 021 μg/g, respectively. In garlic, Se, Cd and Pb are 73. 900 0, 6. 900 0 and 0. 390 0, respectively. All the standard deviations of measured results are below 2.3%, recovery rate are from 99% to 101%.
基金Supported by the Research Project for Postgraduate Students of Minzu University of China in 2015Scientific and Technological Cooperation Planning Project of Guizhou Province(QKJ LH[2015]7265)~~
文摘In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 and H2O2, and detected by the standard curve method. The results showed that Guoshangye contained abundant trace elements which rates of these trace elements were in the curacy and satisfactory. were necessary for human. The recovery range of 96%-103%. The method is ac-
基金Supported by the National Natural Science Foundation of China(No.31060045,31260091)~~
文摘[Objective] This study aimed to identify red pigment of Panax notoginseng fruits and explore the correlation between pigment content and total saponins of the fruits. [Method] The red pigment of Panax notoginseng fruits was preliminarily identi- fied with specific color reactions and UV-vis spectra, and the contents of the pigment and total saponins were determined via spectrophotometry. [Result] The red hues of the fruits were contributed by anthocyanins and/or the anthocyanidins. The contents of anthocyanins and total saponins of the fruits both decreased along with thinning of the red hues. The content difference of the anthocyanins in fruits with different red hues reached extremely significant level, but that of total saponins just reached significant level. [Conclusion] The red pigment of P. notoginseng fruits is anthocyanins which are of extremely significant positive correlation with total saponins in contents.
文摘Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography (CT) method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions.
文摘The liquid ion exchange method, solid salt melt method and dry-wet circulation method were used to prepare natural porous antimicrobial materials with natural minerals, such as zeolite, spilite, palygorskite and montmorillonite, respectively. Atomic absorption spectrum and X-ray diffraction analysis were carried out to investigate the effects of Ag^+ , Cu^2+ and Zn^2+ on antimicrobial abilities of natural porous minerals, and the effect of preparation method on ion exchange capacity of antimicrobial material, respectively. The results show that for the ion exchange capacity, clay mineral is higher than fibrous mineral, i.e. both zeolite and montmorillonite are higher; the antimicrobial ability of material with Ag^+ is the bests the exchange capacities of materials with Cu^2+ or Zn^2+ are all higher, but the antimicrobial ability of Cu^2+ is better than that of Zn^2+ .
文摘Eleven nutrition elements and 5 quality elements of garlic (Allium sativum L.) in different Se, S level and their interaction pot experiments were analyzed by atom absorbing spectrophotometer, titration and fixing sulfur method. The mineral elements were analyzed by the Principal Component Analysis and the Factor Analysis on the SPSS 10.0 and three main factors were picked. The results showed that Se, S and Se-S cooperated application enhanced the garlic nutrition quality by increasing mineral nutrition. The garlic Vc was the highest after using higher Se compared middle S level (S 20 mg/kg soil + Se 40 mg/kg soil). Lower Se level compared middle S level (S 40 mg/kg soil + Se 20 mg/kg soil) get the highest garlic abio-Se in all treatments. The garlic organic Se content was the highest after using higher Se compared middle S (S 40 mg/kg soil + Se 40 mg/kg soil). The treatment lower S compared lower Se level get the highest garlic allicin in all treatment. It showed that the fresh eating factor was affected by the element Se. The flavor factor and health care factor were affected by both Se and S.
文摘Ultraviolet-visible(UV-Vis)spectrophotometry is commonly used in analytical laboratories for qualitative and quantitative analyses.To make the data obtained reliable,an experimental instrument must be calibrated.National Institute for Standards(NIS)in Egypt builds up aphotometric method to ensure the competence of absorbance and transmittance to the standard international and national requirements.This paper presents an instrument for UV-Vis measurement,discusses the factors affecting measurement reliability and estabishes the uncertainty model including correspoding measurement parameters.
文摘The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its existence. Metal ions in foodstuff are in different chemical forms, as inorganic salts or organic molecules or complexes with other compounds such as proteins, amino acids, enzymes and some vitamins, among others, that play an important role in human health. Entomophagy, insect consumption by several ethnic groups in Mexico as cultural tradition since prehispanic era represent an option for population to obtain the minerals needed by the body to keep a good health. Escamoles ant eggs of the Liometopumapiculatum M genus, much appreciated either at rural communities as well as in urban cities, contain minerals with a favorable effect in human health. The aim of this study was to investigate the mineral composition of Escamoles and the benefits which can provide to the human body. Sampling was at an arid region of the Hidalgo state on April 2012. Minerals in dry basis, determined by atomic absorption spectrophotometry, with the exception of phosphorus content, obtained from a triple acid digested extract and determined colorimetrically. Data of mineral analysis in dry basis of Escamoles were: total minerals 5.92%; Na 0.079%; K 0.075%; Ca 0.097%; P 0.701%; Fe 0.021%; Zn 0.035% Cu 0.009%; Mg 0.998%; Mn 0.002%. Minerals quantify are not equal to total ash contained because not all of them were assess determined. Elements concentration depends not only on the total mineral composition of foodstuff the inorganic or organic form or interaction among metal ions, but also on their availability and avail of them. Minerals in Escamoles ant eggs have a considerable influence in the condition of human health.
基金the National Fund for Distinguished Young Scholars of China under,国家自然科学基金,国家重点基础研究发展计划(973计划),上海市科委资助项目
文摘We theoretically investigate the optical absorption spectra and charge density by subjecting a GaAs quantum well to both an intense terahertz (THz)-frequency driving field and an optical pulse within the theory of density matrix. In presence of a strong THz field, the optical transitions in quantum well subbands are altered by the THz field. The alteration has a direct impact on the optical absorption and the charge density. The excitonic peak splitting and THz optical sideband in the absorption spectra show up when changing the THz field intensity and/or frequency. The Autler-Towns splitting is a result from the THz nonlinear dynamics of confined excitons. On the other hand, the carrier charge density is created as wave packets formed by coherent superposition of several eigenstates. The charge density exhibitsquantum beats for short pulses and/or wider wells and is modulated by the THz field.
基金supported by the National Natural Science Foundation of China and China Academy of Engineering Physics under Grant No. 10676025 (NSAF)
文摘The photoabsorption spectra have been calculated for Sis and SilO (n ≤ 5) clusters using time-dependent density-function theory. Our studies suggest that Sin-1 O clusters are relatively stable than those of corresponding Sis clusters. Moreover, substantial differences are observed among the absorption spectra of different molecules in the energy region (0 - 8 eV). Comparing two different exchange-correlation potentials, local-density and generalized-gradient approximations, both calculated optical spectra present the same spectral feature.
文摘On the basis of analysis on the temperature monitoring methods for high voltage devices, a new type of fiber optic sensor structure with reference channel is given. And the operation principle of fiber optic sensor is analysed at large based on the absorption of semiconductor chip. The mathematical model of both devices and the whole system are also given. It is proved by the experiment that this mathematical model is reliable.
文摘Present study is carried out in the bone samples collected from Roopkund Lake in district Chamoli Garhwal, Uttarakhand which is located at 5,029 meters from main sea level in between Nanda Ghunghti and Trishuli peak. This historical site belongs to 9th century A.D. All the samples selected for the study were dried in room temperature as well as hot air oven at 32 ~C. Cleaning, pretreatment and digestion process of faunal remains was followed through established scientific methods. Chemical analysis i.e. concentration of different elements such as calcium, strontium, barium, magnesium and zinc as well as isotopic ratios of Carbon and Nitrogen was estimated with the help of ICP (inductively coupled plasma spectroscopy) and AAS (atomic absorption spectrophotometer). The results obtained from the chemical analysis are significant. On the basis of concentration of different elements and ratios of Nitrogen and Carbon isotopes, the dietary habits of the peoples buried in the Roopkund Lake are identified, which is different from sample to sample person to person. Besides this, the results are also significantly helpful for knowing the preservation status of faunal remains in Roopkund Lake. Finally this study also indicated the potentiality of chemical analysis for reconstructing the palaeodiet behaviour and preservation status of bone remains.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10405025, 10575012, 10435020, and 10535010
文摘With the frame of the time-dependent local density approximation, an efficient description of the optical response of clusters has been used to study the photo-absorption cross section of Na2 and Na4 clusters. It is shown that our calculated results are in good agreement with the experiment. In addition, our calculated spectrum for the Na4 cluster is in better agreement with experiment than the GW absorption spectrum.
基金Supported by the National Natural Science Foundation of China(No.20967003)the Project of the Government of Guiyang City(No.[2010]5-2)
文摘The bioavailability of five divalent cationic heavy metals (Pb, Cd, Cu, Zn and Ni) in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals (SEMs) to acid volatile sulfide (AVS). Atomic absorption spectrometry (AAS) and X-ray powder diffraction (XRD) were used to determine the heavy metal concentrations and examine the mineralogy of the crystalline phases, respectively. The AVS loadings in sediments from Baihua Lake ranged from 64.30 to 350.08 ~rnol/g (dry weight). The corresponding SEM levels for the sampling sites varied from 1.770 to 14.660 vrnol/g. The molar ratio of SEMs to AVS ranged from 0.014 to 0.084 with a mean value of 0.034. The XRD analysis also confirmed the presence of some metal sulfides in sediments from Baihua Lake. The SEMs/AVS ratios for all sampling sites were significantly lower than 1.0, indicating that AVS in the sediments was sufficient to bind the five heavy metals; thus, these heavy metals are currently not significantly bioavailable to benthic organisms. Comparing the SEMs results to published guideline values for metal toxicity to benthic organisms in sediments, however, suggests that Zn and Ni pose a risk at some sampling locations in Baihua Lake.
文摘Based upon the standard deviations for the intercept and the slope of a linear regression line, as well as by differentiating both Beer's law and a linear relationship between transmittance and concentration at high transmission, it is proved that the relative spectrophotometric error of a measurement becomes greater as the sample concentration only decreases. Further, it is demonstrated that the present knowledge with regard to the error in absorption spectrophotometry is necessary to be reexamined. The total scale of transmittance can literally be used for measurements, unfolding workable dynamic ranges about two orders of magnitude lower than usually and thus absorption spectrophotometry can efficiently compete with other methods of analysis with respect to detection limits.
基金Project(2009K06_03) supported by the Scientific and Technological Program of Shaanxi Province,China
文摘Infrared emissivity was studied in Zno.99Mo.olO (M is Mn, Fe or Ni) and Znl_xCoxO (x=0.01, 0.02, 0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2+ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest (0.829) and that of Zno.99C00.010 is the lowest (0.784) at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum (0.752) at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.
文摘2,7′-(Ethylene)-bis-8-hydroxyquinoline was optimized with DFT/B3LYP and ab initio HF methods, so ion- ization potential and electron affinity could be determined. Absorption spectrum was calculated by ZINDO and TD-DFT. CIS method was used to calculate the S1 excited states of the compound and afterwards the emission spectrum was computed. When the solvent effect was taken into account, the computed results show encouraging agreement with known experimental data. The results of analyzing the relationship between the energies and absorption spectra indicate that the ability to transporting electrons is strengthened compared with 8-hydroxyquinoline and that absorption and emission spectra are red-shifted. The intramoleeular reor- ganization energy of tris(2,7′-(ethylene)-bis-8-hydroxyquinoline)-aluminum implies its electron transporting property is worse than tris(8-hydroxyquinoline)-aluminum. The predicted maximum emission wavelength is red-shifted compared with tris(8-hydroxyquinoline)-aluminum.
文摘A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban (236), rural (80) and industrial areas (97) were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer (GFAAS). Cognitive development was measured by the 'McCarthy Scales of Children's Abilities Test' (MSCA). Significant differences found in the mean cognitive scores between the urban (94.40), industrial (102.90) and suburban children (101.24) (p 〈 0.001), with the blood lead between the urban (3.66 p.g/dL), industrial (3.54 μg/dL) and suburban children (3.04μg/dL) (p = 0.022). Significant inverse correlations between blood lead and cognitive scores found for all groups (p 〈 0.001), urban (p 〈 0.001) and suburban children (p 〈 0.001). Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders (p _〈 0.001). The urban children's cognitive scores were significantly influenced by blood lead levels and household income (p 〈 0.001). However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers' education, number of siblings, sequence in the family and the household income (p 〈 0.001 ). Blood lead below 10μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development.