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夏俊娜与维米尔艺术风格相似性探析 被引量:2
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作者 张军 《电影评介》 北大核心 2007年第11期81-,共1页
夏俊娜与维米尔在题材、绘画语言、个人喜好等方面有着惊人的相似之处。夏俊娜和维米尔绘画作品之所以有诸多相似之处,主要是缘于他们对生活的感悟和对艺术的追求存在高度契合性。
关键词 夏俊娜 维米尔 静物化 家庭生活
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FTIR analysis of adsorption of poly diallyl-dimethyl-ammonium chloride on kaolinite 被引量:4
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作者 孙伟 刘文莉 胡岳华 《Journal of Central South University of Technology》 EI 2008年第3期373-377,共5页
The flocculation behavior of ultrafine kaolinite suspension was investigated through settlement tests and FTIR method was employed to probe the adsorption mechanism of flocculant on kaolinite. The results show that th... The flocculation behavior of ultrafine kaolinite suspension was investigated through settlement tests and FTIR method was employed to probe the adsorption mechanism of flocculant on kaolinite. The results show that the maximum settling rate of kaolinite occurs at pH value of 3.33,which is close to the point of zero charge(PZC) of kaolinite (3.5). This result is in good agreement with the double electric layer theory. Kaolinite suspension reaches the largest settling rate at a low concentration of 39 g/t for poly diallyl-dimethyl-ammonium chloride(PDADMA) flocculant,whereas for polyacrylamides(PAM) the dosage is required to be 500 g/t. When macromolecule polymer is adsorbed on surface,kaolinite particles may be flocculant due to the bridging effect. There are cation flocculant characteristic bands on the spectrum of kaolinite but no obvious shifting. Thus,the adsorption of poly diallyl-dimethyl-ammonium chloride on kaolinite surface is physical adsorption. 展开更多
关键词 ADSORPTION FTIR spectrum KAOLINITE poly diallyl-dimethyl-ammonium chloride ELECTROSTATIC FLOCCULANT
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Succession and biodiversity indices in eutrophication process of static landscaping water body in northern China 被引量:1
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作者 丛科明 刘书宇 +2 位作者 马放 张建祺 任南琪 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第5期711-717,共7页
Many biodiversity indices were used to indicate the biological contamination degree in studies of lake water or seawater. Some were studied on biodiversity comparison for different areas at the same time, or initial s... Many biodiversity indices were used to indicate the biological contamination degree in studies of lake water or seawater. Some were studied on biodiversity comparison for different areas at the same time, or initial structure succession of some aerial lake water systems. The phytoplankton changed with the development of various dominant species. In this study, the dominant species at these stages were Chlorophyta in the beginning stage, Cyanophyta in the second stage, and Xanthophyta in the last stage. Seven of nine biodiversity indices (Margalef's, IE, Shannon-Wiener, Simpson's, McNaughton's, Species and Odds Measure of Diversity) showed their failure to represent the eutrophication trend, and the other two indices (Menhinick's and Monk) exhibited good efficiency to indicate the eutrophication trend for the static landscaping water body. 展开更多
关键词 biodiversity indices eutrophication assessment static lake water
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Physical-Chemical Aggressiveness of Solutions of Medicines as a Factor in the Rheology of the Blood inside Veins and Catheters
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作者 Aleksandr Urakov Natalia Urakova +1 位作者 Anton Kasatkin Leisan Chernova 《Journal of Chemistry and Chemical Engineering》 2014年第1期61-65,共5页
In experiments in vitro and observations in the clinic in vivo studied the state of the lumen of subcutaneous veins and blood rheology of patients after their interaction with vascular catheters and solutions of medic... In experiments in vitro and observations in the clinic in vivo studied the state of the lumen of subcutaneous veins and blood rheology of patients after their interaction with vascular catheters and solutions of medicines based on the values of temperature, volume, concentration, osmotic activity and pH. It is shown that heparin injection in blood not prevent, but solution of 4% sodium bicarbonate injection prevents blood clotting, blood clots and blockage blood clots of veins and of catheters. It is shown that the heating to a temperature of+42 ℃ with the solution of 4% sodium bicarbonate provides softening action on old dry blood clots in 1 min, and their subsequent irrigation with a warm solution of 4% sodium bicarbonate and 3% hydrogen peroxide provides complete destruction and discoloration of the remaining spots of blood during 2 s. Proposed new medicines and hygiene products for the protection of the veins and installed in them vascular catheters from blockage of blood clots, and for removing blood stains from clothes and body surface patients. 展开更多
关键词 New drugs hygiene products physical-chemical properties rheology blood.
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Oxidative stress in portal hypertension-induced rats with particular emphasis on nitric oxide and trace metals 被引量:1
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作者 Titiz Izzet Krand Osman +9 位作者 Unal Ethem Yavuz Nihat Kusaslan Ramazan Dogan Mustafa Uzun Hafize Kiziler Ali Riza Aydemir Birsen Genc Habibe Aydin Seval Simsek Gonul 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第23期3570-3573,共4页
AIM: To investigate the oxidative-stress-related changes in rats with portal hypertension with particular emphasis on nitric oxide (NO) and trace metals. METHODS: Cirrhosis was induced by partial portal vein ligation ... AIM: To investigate the oxidative-stress-related changes in rats with portal hypertension with particular emphasis on nitric oxide (NO) and trace metals. METHODS: Cirrhosis was induced by partial portal vein ligation (PVL) in Wistar rats. The lipid peroxidation marker (malondialdehyde, MDA), antioxidant defense enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and agents known to have antioxidant features including nitric oxide (NO), zinc (Zn), copper (Cu) were determined both in serum and in liver tissue at 4 wk after surgery in PVL and sham-operated rats. Portal pressure of all experimental animals was measured. MDA was detected by thiobarbituric acid reactivity assay.SOD activity was determined by inhibition of nitroblue tetrazolium reduction with xanthine/xanthine oxidase used asa superoxide generator. CAT activity was determined by the breakdown of hydrogen peroxide. GSH concentrations were measured by using metaphosphoric acid for protein precipitation and 5'-5'-dithio-bis-2-nitrobenzoic acid for color development. NO was detected by the Griess method after reduction of nitrate to nitrite with nitrate reductase, and the concentrations of Zn and Cu were measured by a Shimadzu 680 AA atomic absorption spectrometer. Histopathological confirmation was done under light microscope. Statistical analyses were done by Student's t-test, and significance of the difference was tested by the unpaired Mann-Whitney test. P<0.05 was considered statistically significant.RESULTS: Histopathological studies confirmed PVL induced cirrhotic changes. There was a statistically significant difference in portal pressure between PVL and control groups (P<0.001). The results showed significant increases in the levels of MDA and NO in both tissue and serum (P<0.05 and P<0.001, respectively in tissue; P<0.001 for each in serum), and Zn only in tissue (P<0.001)in rats with PVL compared with sham-operated rats. Besides, PVL rats exhibited reduced plasma and tissue GSH, CAT, SOD (P<0.001 for each). Serum and tissue Cu concentration did not change.CONCLUSION: Our findings suggest that PVL in rats induces important biochemical and molecular changes related to oxidative stress in the liver. 展开更多
关键词 Portal hypertension Nitric oxide Lipid peroxidation ANTIOXIDANTS Trace metals
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Variation of Two-photon Absorption Cross Sections and Optical Limiting of Compounds Induced by Static Electric Field
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作者 Yu-jin Zhang Yu-zhi Song Chuan-kui Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第3期259-264,共6页
By numerically solving the Maxwell-Bloch equations using an iterative predictor-corrector finite-difference time-domain technique, we investigate propagating properties of a few-cycle laser pulse in a 4,4'-bis(di-n-... By numerically solving the Maxwell-Bloch equations using an iterative predictor-corrector finite-difference time-domain technique, we investigate propagating properties of a few-cycle laser pulse in a 4,4'-bis(di-n-butylamino) stilbene (BDBAS) molecular medium when a static electric field exists. Dynamical two-photon absorption (TPA) cross sections are obtained and optical limiting (OL) behavior is displayed. The results show that when the static electric field intensity increases, the dynamical TPA cross section is enhanced and the OL behavior is improved. Moreover, both even- and odd-order harmonic spectral components are generated with existence of the static electric field because it breaks the inversion symmetry of the BDBAS molecule. This work provides a method to modulate the nonlinear optical properties of the BDBAS compounds. 展开更多
关键词 Static electric field Optical limiting Two-photon absorption Organic molecule
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Functional lipidomics in patients on home parenteral nutrition: Effect of lipid emulsions 被引量:1
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作者 Loris Pironi Mariacristina Guidetti +6 位作者 Ornella Verrastro Claudia Iacona Federica Agostini Caterina Pazzeschi Anna Simona Sasdelli Michele Melchiorre Carla Ferreri 《World Journal of Gastroenterology》 SCIE CAS 2017年第25期4604-4614,共11页
To investigate the fatty acid-based functional lipidomics of patients on long-term home parenteral nutrition receiving different intravenous lipid emulsions. METHODSA cross-sectional comparative study was carried out ... To investigate the fatty acid-based functional lipidomics of patients on long-term home parenteral nutrition receiving different intravenous lipid emulsions. METHODSA cross-sectional comparative study was carried out on 3 groups of adults on home parenteral nutrition (HPN), receiving an HPN admixture containing an olive-soybean oil-based intravenous lipid emulsion (IVLE) (OO-IVLE; n = 15), a soybean- medium-chain triacylglycerol-olive-fish oil-based IVLE (SMOF-IVLE; n = 8) or HPN without IVLE (No-IVLE; n = 8) and 42 healthy controls (HCs). The inclusion criteria were: duration of HPN ≥ 3 mo, current HPN admixtures ≥ 2 mo and HPN infusions ≥ 2/wk. Blood samples were drawn 4-6 h after the discontinuation of the overnight HPN infusion. The functional lipidomics panel included: the red blood cell (RBC) fatty acid (FA) profile, molecular biomarkers [membrane fluidity: saturated/monounsaturated FA ratio = saturated fatty acid (SFA)/monounsaturated fatty acid (MUFA) index; inflammatory risk: n-6/n-3 polyunsaturated fatty acid (PUFA) ratio = n-6/n-3 index; cardiovascular risk: sum of n-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) = n-3 index; free radical stress: sum of FA trans isomers = %trans index] and FA pathway enzyme activity estimate (delta-9-desaturase = D9D; delta-6-desaturase = D6D; delta-5-desaturase = D5D; elongase = ELO). Statistics were carried out using nonparametric tests. The amount of each FA was calculated as a percentage of the total FA content (relative%). RESULTSIn the OO-IVLE group, the percentage of oleic acid in the RBCs was positively correlated with the weekly load of OO-IVLE (r = 0.540, P = 0.043). In the SMOF-IVLE cohort, the RBC membrane EPA and DHA were positively correlated with the daily amount of SMOF-IVLE (r = 0.751, P = 0.044) and the number of HPN infusions per week (r = 0.753; P = 0.046), respectively. The SMOF-IVLE group showed the highest EPA and DHA and the lowest arachidonic acid percentages (P < 0.001). The RBC membrane linoleic acid content was lower, and oleic and vaccenic acids were higher in all the HPN groups in comparison to the HCs. Vaccenic acid was positively correlated with the weekly HPN load of glucose in both the OO-IVLE (r = 0.716; P = 0.007) and the SMOF-IVLE (r = 0.732; P = 0.053) groups. The estimated activity of D9D was higher in all the HPN groups than in the HCs (P < 0.001). The estimated activity of D5D was lower in the SMOF-IVLE group than in the HCs (P = 0.013). The SFA/MUFA ratio was lower in all the HPN groups than in the HCs (P < 0.001). The n-6/n-3 index was lower and the n-3 index was higher in the SMOF-IVLE group in comparison to the HCs and to the other HPN groups (P < 0.001). The %trans index did not differ among the four groups. CONCLUSIONThe FA profile of IVLEs significantly influenced the cell membrane functional lipidomics. The amount of glucose in the HPN may play a relevant role, mediated by the insulin regulation of the FA pathway enzyme activities. 展开更多
关键词 Chronic intestinal failure Home parenteral nutrition Intravenous lipid emulsion Cell membrane fatty acid profile Cell membrane lipidome Functional lipidomics
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Influence of Conditions on Reuterin Accumulation by the Resting Cell Biotransformation Process
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作者 陈国 杨道茂 +1 位作者 肖雅琴 陈宏文 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第6期1023-1027,共5页
3-Hydroxypropionaldehyde (3-HPA) is a potential valuable chemical and new broad-spectrum antim-icrobial substance. In order to improve the conversion of 3-HPA/glycerol, our work studied the two-step process from gly... 3-Hydroxypropionaldehyde (3-HPA) is a potential valuable chemical and new broad-spectrum antim-icrobial substance. In order to improve the conversion of 3-HPA/glycerol, our work studied the two-step process from glycerol to 3-HPA, and investigated the influence of cell harvest time, glycerol concentration, biomass con-centration, pH and temperature on the production of 3-HPA by Lactobacillus reuteri CG001, respectively. The re-sults showed that molar conversion yield of 3-HPA/glycerol reached 97.9% under the condition that 200 mmol·L-1 glycerol was converted by 25.3 g·L-1 resting cell for 1 h at 30 ℃. The cells could not be reused directly because the L. reuteri almost lost its bioconversion activity completely, but the ability of glycerol conversion could gradually recover if the fresh medium was added to the deactivated cell for 4 h. 展开更多
关键词 Lactobacillus reuteri 3-HYDROXYPROPIONALDEHYDE REUTERIN bioconversion
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Estimation of Separation of Electrolytes and Organic Compounds by Nanofiltration Membranes Using an Irreversible Thermodynamic Modei
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作者 Pallab Ghosh 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第5期583-588,共6页
Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving an... Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving and diffusion. In the present work, a model based onirreversible thermodynamics is extended and used to estimate rejection of inorganic salts andorganic substances. Binary systems are modeled, where the feed contains an ion that is much lesspermeable to the membrane as compared with the other ion. The two model parameters are estimated byfitting the model to the experimental data. Variation of these parameters with the composition ofthe feed is described by an empirical correlation. This work attempts to describe transport throughthe nanofiltration membranes by a simple model. 展开更多
关键词 DIFFUSION donnan equilibrium electrostatic repulsion ion adsorption irreversible thermodynamics NANOFILTRATION polymeric membranes steric hindrance surface charge
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Sulindac derivative-induced apoptosis in a human umbilical vein endothelial cell line ECV304
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作者 刘素英 丰有吉 《Chinese Medical Journal》 SCIE CAS CSCD 2002年第7期1074-1077,共4页
Objective To investigate the effects of sulindac metabolites on proliferation and apoptosis in the human umbilical vein endothelial cell line ECV304 in vitro Methods The proliferation profile of ECV304 was dete... Objective To investigate the effects of sulindac metabolites on proliferation and apoptosis in the human umbilical vein endothelial cell line ECV304 in vitro Methods The proliferation profile of ECV304 was determined by methyl thiazolyl tetrazolium (MTT) method Cell cycle distribution, apoptosis and the ultrastructure of ECV304 were detected by flow cytometry (FCM) and electron microscopy, respectively Results MTT assay showed that the sulfide inhibited the proliferation of ECV304 and its effect was dose dependent; the IC 50 was 200 μmol/L FCM showed that the sulfide changed cell cycle distribution The cell cycle distribution was as follows: G 1 phase (control group 77 74%±1 58%; sulfone group 75 63%±2 12%; sulfide group 46 12%±1 60%); S phase (control group 13 64%±1 22%; sulfone group 16 40±2 30%; sulfide group 27 26%±2 08%); G 2 M phase (control group 8 61%±0 67%; sulfone group 7 98%±0 49%; sulfide group 26 62%±3 54%) The apoptosis rates in the control group, sulfone group and sulfide group were 6 08%±3 39%, 4 81%±2 14% and 51 90%±5 67%, respectively Sulfide reduced the proportion of G 1 phase, increased the proportion of S phase, G 2 M phase and the apoptosis rate significantly ( P <0 01, vs control) In the sulfide treated cells, there were nuclear fragmentation and chromosomal condensation, shrinkage of the cell and loss of contact with neighboring cells Apoptotic bodies were observed Sulfone showed no effect on cell proliferation, cell cycle distribution or cell morphology Conclusions Sulfide can significantly reduce the proliferation of ECV304, change the cell cycle distribution and arrest cells in G 2 M phase where apoptosis may be induced Sulfone has no such effects on this cell line 展开更多
关键词 sulindac sulfide · sulindac sulfone · human umbilical vein endothelial cell line · apoptosis
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Green and efficient cycloaddition of CO2 toward epoxides over thiamine derivatives/GO aerogels under mild and solvent-free conditions 被引量:1
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作者 Ziqi Yi Donghui Lan +3 位作者 Ying Wang Lang Chen Chaktong Au Shuangfeng Yin 《Science China Chemistry》 SCIE EI CAS CSCD 2017年第7期990-996,共7页
Thiamine derivatives that are cheap, readily available, non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO_2 to epoxides without the need of co-c... Thiamine derivatives that are cheap, readily available, non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO_2 to epoxides without the need of co-catalyst and solvent. The interaction between thiamine hydrochloride(VB_1-Cl) and substrates(CO_2 and propylene oxide) was proven by ultraviolet-visible spectroscopy and ~1H nuclear magnetic resonance analysis, and it is deduced that the synergistic action among multi-functional groups(hydroxyl, halide anion and amine) is a favorable factor for cycloaddition reaction. A series of VB_1/GO aerogels were facilely prepared through the addition of aqueous VB_1 derivatives to a suspension of GO in ethanol at room temperature. It was found that the aerogel generated through the interaction of VB_1-Cl with GO shows catalytic activity and stability higher than those of VB_1-Cl. It is because the electrostatic interaction between GO and VB_1-Cl enhances the nucleophilicity and leaving ability of anion. The effects of reaction temperature, catalyst loading, CO_2 pressure and reaction time on CO_2 cycloaddition to propylene oxide were thoroughly studied. 展开更多
关键词 thiamine B1 graphene oxide aerogels synergetic effect carbon dioxide cycloaddition reaction
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Multifunctional electrospinning composite fibers for orthotopic cancer treatment in vivo 被引量:2
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作者 Yinyin Chen Shi Liu +4 位作者 Zhiyao Hou Pingan Ma Dongmei Yang Chunxia Li Jun Lin 《Nano Research》 SCIE EI CAS CSCD 2015年第6期1917-1931,共15页
A multifunctional, dual-drug carrier platform was successfully constructed. Core-sheU structured NaGdF4:Yb/Er@NaGdF4:Yb@mSiO2-polyethylene glycol (abbreviated as UCNPS) nanopartides loaded with the antiturnor drug... A multifunctional, dual-drug carrier platform was successfully constructed. Core-sheU structured NaGdF4:Yb/Er@NaGdF4:Yb@mSiO2-polyethylene glycol (abbreviated as UCNPS) nanopartides loaded with the antiturnor drug, doxorubicin (DOX) were incorporated into poly(^-caprolactone) (PCL) and gelatin loaded with antiphlogistic drug, indomethacin (MC) to form nanofibrous fabrics (labeled as MC/UCNPS/DOX) via electrospinning process. The resultant multifunctional spinning pieces can be surgically implanted directly at the tumor site of mice as an orthotopic chemotherapy by controlled-release DOX from mesoporous silicon dioxide (SiO2) and upconversion fluorescence/magnetic resonance dual-model imaging through NaGdF4:Yb/Er@NaGdF4:Yb embedded in MCfldCNPS/DOX invivo. 展开更多
关键词 electrospinning orthotopic TREATMENT controlled release multiple structure
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An Improved Study of Electronic Band Structure and Optical Parameters of X-Phosphides (X=B, Al, Ga, In) by Modified Becke-Johnson Potential
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作者 Masood Yousaf M.A. Saeed +3 位作者 R. Ahmed M.M. Alsardia Ahmad Radzi Mat Isa A. Shaari 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第11期777-784,共8页
We report the electronic band structure and optical parameters of X-Phosphides (X=B, AI, Ga, In) by first-principles technique based on a new approximation known as modified Becke-Johnson (roB J). This potential i... We report the electronic band structure and optical parameters of X-Phosphides (X=B, AI, Ga, In) by first-principles technique based on a new approximation known as modified Becke-Johnson (roB J). This potential is considered more accurate in elaborating excited states properties of insulators and semiconductors as compared to LDA and GGA. The present calculated band gaps values of BP, AlP, GaP, and InP are 1.867 eV, 2.268 eV, 2.090 eV, and 1.377 eV respectively, which are in close agreement to the experimental results. The band gap values trend in this study is as: E9 (mBJ-GGA/LDA) 〉 E9 (GGA) 〉 Eg (LDA). Optical parametric quantities (dielectric constant, refractive index, reflectivity and optical conductivity) which based on the band structure are aiso presented and discussed. BP, AlP, GaP, and InP have strong absorption in between the energy range 4-9 eV, 4-7 ev, 3-7 eV, and 2-7 eV respectively. Static dielectric constant, static refractive index and coefficient of reflectivity at zero frequency, within mBJ-GGA, are also calculated. BP, AIP, GaP, and InP show significant optical conductivity in the range 5.2-10 eV, 4.3-8 eV, 3.5- 7.2 eV, and 3.2-8 eV respectively. The present study endorses that the said compounds can be used in opto-electronic applications, for different energy ranges. 展开更多
关键词 DFT FP-LAPW lo mBJ-GGA optical properties electronic structure
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^(40)Ar/^(39)Ar dating of cryptomelane from the Baye manganese deposit,SW Yunnan,China:Implications for growth rate of supergene Mn-oxide veins
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作者 DENG XiaoDong LI JianWei 《Science China Earth Sciences》 SCIE EI CAS 2013年第10期1654-1663,共10页
Supergene Mn-oxide deposits are commonly related to thick weathering profiles and form as a result of intense and prolonged weathering of Mn-bearing precursor rocks, processes facilitated by a combination of multiple ... Supergene Mn-oxide deposits are commonly related to thick weathering profiles and form as a result of intense and prolonged weathering of Mn-bearing precursor rocks, processes facilitated by a combination of multiple factors including warm and wet climate, relatively quiescent tectonic environment, and favorable geomorphic setting. Precise age constraints of supergene Mn-oxides may provide valuable information on the climatic, tectonic, and geomorphic conditions prevailing in the geological past. 4~Ar]39Ar laser incremental heating analysis of cryptomelane from the Baye manganese deposit, western Yunnan-Guizhou Plateau, SW China, was conducted to provide numerical constraints on the ages of supergene Mn enrichment and growth rates of Mn-oxide veins. In this study, two Mn-oxide veins of 3-6 cm thickness, termed as Vein A and B, respectively, were col- lected for 4~Ar/39Ar dating. Vein A is subhorizontal and present in fractures parallel to schistosity of the Proterozoic spessartine schists, whereas Vein B is filled in nearly vertical fractures penetrating the schistosity. A combination of optical microscopy, XRD, SEM, and EMP analyses demonstrate that mineral grains extracted from both veins consist of pure, well-crystallized cryptomlane, which has acicular crystal forms and contains 0.96%4.70% K2O. Fourteen cryptomelane subsamples extracted from different growth bands of Vein A yield well-defined plateau ages ranging from 1.35 ± 0.05 to 1.16 ± 0.04 Ma (2or), whereas seven subsamples obtained from Vein B have plateau ages ranging from 1.23 ±0.05 to 1.01 ± 0.04 Ma (20). The age results permit estimation for the growth rates of both veins at ca. 115-153 and 34-67 mm Ma-1, respectively. Distinct growth rates between Veins A and B are likely reflective of different fluid pressures during their formation governed by the orientation of the fractures hosting the veins. The growth rates calculated for both veins are 1-2 orders of magnitude higher than the val- ues (〈1-10 mm Ma-l) estimated for Mn-oxide nodules in supergene Mn deposits elsewhere. The high growth rates obtained for the Baye samples are consistent with direct precipitation of tetravalent Mn-oxides from weathering solution in open cavities or fractures, characterized by incremental growth of Mn-oxide bands from the margin to the center of the cavities or fractures. In contrast, Mn-oxide nodules with low growth rates from other deposits formed through self-oxidation and self-catalization, and grow outwards from the nuclei. In addition, prevalence of warm and humid climate and prolonged tectonic uplift in the Yunnan Plateau may have also partly contributed to the rapid growth of Mn-oxides in the Baye deposit. 展开更多
关键词 CRYPTOMELANE 40Ar/39Ar dating growth rates growth mechanism Yunnan.Guizhou Plateau
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