检索结果-南通市图书馆

Layer-by-layer assembly carbon nanotubes thin film based gas sensors for ammonia detection

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第12期54卷 2700-2706页

作者： SUN Ping 1,2 , JIANG YaDong 1* , XIE GuangZhong 1 , DU XiaoSong 1 , LI Xian 1 & HU Jia 1 1 School of Optoelectronic Information, State Key Laboratory of Electronic Thin Films and Integrated Devices, university of Electronic science and Technology of china (UESTC), Chengdu, 610054, china 2 Life and Physical science college, Sichuan agricultural university, Ya’an 625014, china 1. School of Optoelectronic Information State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China (UESTC) Chengdu 610054 China2. Life and Physical Science College Sichuan Agricultural University Ya’an 625014 China

Single walled carbon nanotubes (SWNTs) were deposited on interdigital electrode (IDE) devices and quartz crystal microbalance (QCM) devices through layer-by-layer self-assembly method to fabricate resistance sensitive and mass sensitive gas sensors, respectively. Their ammonia gas-sensitive characteristics were detected at different temperature. It is revealed that the SWNTs based mass sensitive gas sensor has good sensing properties at room temperature. However, the SWNTs based resistance sensitive gas sensor has irreversible response for ammonia gas. When the temperature increases, the noise of SWNTs based mass sensitive gas sensor increases and the gas sensitive characteristic decreases. Meanwhile, the humidity effect is also discussed. It is important to optimize gas sensor by making it work at an appropriate external environment.

关键词： layer-by-layer self-assembly carbon nanotube gas sensor

Further study of sources of the imported cobalt-blue pigment used on Jingdezhen porcelain from late 13 to early 15 centuries

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Technological sciences) 2008年第3期51卷 249-259页

作者： DU Feng1 & SU BaoRu2 1 Institute of Chemistry & Molecular Engineering, Qingdao university of science & Technology, Qingdao 266000, china 2 college of Information science Technology, Qingdao university of science & Technology, Qingdao 266000, china Institute of Chemistry & Molecular Engineering Qingdao University of Science & Technology Qingdao 266000 China college of Information science Technology Qingdao University of Science & Technology Qingdao 266000 China

Based on the conclusion of modern scientific analysis: the cobalt-blue pigment applied on Jingdezhen official porcelain during Yuan Dynasty and prior to Xuande reign of Ming Dynasty (1271―1425) contains high iron and low manganese con- tents, and the cobalt during Xuande and after Xuande periods (after 1426) of Ming Dynasty contains high manganese and low iron contents, in combination with the traditional archaeological method, the related historical textual records were in- vestigated and analyzed, the imported cobalt employed on Jingdezhen official porcelain was studied comprehensively, systematically and logically. In fact, 'Su Ma Li Qing' (Samarra-blue) and 'Su Bo Ni Qing' (Sumatra-blue) are definitely different cobalt ores originated in different places, because of their very similar translitera- tions in Chinese, the confusion has appeared in ancient books for more than 400 years, which considered 'Su Ma Li Qing' and 'Su Bo Ni Qing' as the same co- balt-blue pigment. In this article the mistake was corrected, the possible producing places and the approximate eras of the two pigments imported to china and used at Jingdezhen were also suggested.

关键词： imported cobalt-blue pigments employed on official blue-and-white porcelain Yuan Dynasty early Ming Dy- nasty Mn/Fe content ratio Su Ma Li Qing (Samarra-blue) Su Bo Ni Qing (Sumatra-blue) scientific archae- ological research transliteration

Effects of genistein, daidzein and glycitein on the osteogenic and adipogenic differentiation of bone marrow stromal cells and on the adipogenic trans-differentiation of osteoblasts

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第11期15卷 993-999页

作者： LI Xianghui, ZHANG Jinchao, SUI Senfang and YANG Mengsu (State Key Laboratory of Biomembrane, Department of Biological sciences and Biotechnology, Tsinghua university, Beijing 100084, china Department of Chemistry, college of Chemistry & Environmental science, hebei university, baoding 071002, china Department of Biology and Chemistry, City university of Hong Kong, Hong Kong, china) State Key Laboratory of Biomembrane Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China. Department of Chemistry College of Chemistry & Environmental Science Hebei University Baoding 071002 China. Department of Biology and Chemistry City University of Hong Kong Hong Kong China

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), alkaline phosphatase (ALP) activity and oil red O assays were used to examine the effects of genistein, daidzein and glycitein on the osteogenic and adipogenic differentiation of primary mouse bone marrow stromal cells (MSCs) and the adipogenic trans-differentiation of primary mouse osteoblasts. The results indicated that daidzein, genistein and glycitein at concentrations from 1×10-8 mol/L to 1×10-5mol/L promoted the proliferation of MSCs and osteoblasts; genistein, daidzein and glycitein promoted osteogenic differentiation and inhibited adipogenic differentiation of MSCs, and inhibited adipocytic transdifferentiation of osteoblasts at appropriate concentrations as 17β-estradiol. It suggests that genistein, daidzein and glycitein regulate a dual differentiational process of MSCs into the osteogenic and adipogenic lineages, and trans-differentiational process of primary osteoblasts into the adipocyte lineages, causing a lineage shift toward osteoblast. Protective effects of them on bone may be mediated by a reversal of adipogenesis which may promote the proliferation, differentiation and mineralization of osteoblasts, and make adipocytes secrete less cytokines which may promote osteoclast formation and activation. In addition, the results also indicated that genistein, daidzein and glycitein may be helpful in preventing the development of steroid induced osteonecrosis.

关键词： genistein daidzein glycitein bone marrow stromal cells osteoblasts osteogenic differentiation adipogenic differentiation adipogenic trans-differentiation.

Facile Synthesis of Nanocrystalline Cr_2O_3 Thin Film

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials science) 2011年第6期26卷 1032-1035页

作者：杨明 School of Transportation Southeast University

A novel and facile synthesis route for the manufacture of transparent and uniform self-assembled nanocrystalline Cr2O3 （nc-Cr2O3） thin films with different morphology was reported, utilizing chromium nitrate as the inorganic source and triblock copolymer F127 as the morphology-directing agent by the evaporation-induced assembly （EIA） method. X-ray powder diffraction （XRD）, thermogravimetry-differential scanning calorimetry （TG-DSC）, N2-sorption, scanning electron microscopy （SEM） and transmission electron microscopy （TEM） were used to characterize the as-prepared nc-Cr2O3 thin films. The Cr2O3 thin film with different morphology was obtained by changing the relative humidity. The possible formation mechanism of the nc-Cr2O3 thin films with different morphologies was discussed.

关键词： microstrucmre Cr2O3 thin film

Aberrant DNA methylation patterns in cultured mouse embryos

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第12期15卷 1079-1083页

作者： HOU Jian,CUI Xiuhong,LEI Tinghua,LIU Lei,AN Xiaorong and CHEN Yongfu State Key Laboratory for Agrobiotechnology and Department of animal Physiology,college of Biological science,china agricultural university,Beijing 100094,china State Key Laboratory for Agrobiotechnology and Department of animal Physiology College of Biological Science China Agricultural University Beijing 100094 China

Mouse early embryos undergo genome-wide demethylation and remethylation events during pre-implantation *** methylation reprogramming is thought to be associated with development *** immunofluorescence staining with an antibody against 5-methylcytosine (MeC),we examined the genome methylation patterns of mouse embryos cultured in *** results did not show the difference in staining patterns between development-blocked two-cell embryos that cultured in vitro and the two-cell embryos that were freshly collected from the donor *** in vitro-arrested morulae displayed a strong positive staining when compared to the morulae freshly collected from the donor *** the blastocyst stage,although most embryos showed the expected methylation patterns,with highly stained inner cell mass (ICM) and weekly stained trophectoderm (TE),a proportion of embryos were dimly stained in both ICM and *** results indicated that the methylation profile of the embryos could be changed by culturing in vitro when the embryos were in the transition from morulae to blastocyst.

关键词： methylation mouse embryo 5-methylcytosine antibody

Investigation of thermoluminescence in Li_2B_4O_7 phosphors doped with Cu, Ag and Mg

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2007年第3期50卷 311-320页

作者： XIONG ZhengYe1,2, TANG Qiang2 & ZHANG ChunXiang2 1 college of science, Guangdong Ocean university, Zhanjiang 524088, china 2 School of Physics science and Engineering, Sun Yat-sen university, Guangzhou 510275, china 1. college of science Guangdong Ocean University Zhanjiang 524088 China 2. School of Physics science and Engineering Sun Yat-sen University Guangzhou 510275 China

Li2B4O7 （LBO）:Cu,Ag,Mg phosphors have been prepared by the sintering technique. The roles of the Ag and Mg dopants in the phosphors have been studied using the methods of thermoluminescence （TL） glow curves and TL 3D spectra. The results indicated that proper concentrations of Ag and Mg can enhance the TL of LBO:Cu. It was also indicated that the intensity of TL peak at 130℃ is reduced with the in- creasing Ag concentration, and enhanced with the increasing Mg concentration. From the TL 3D spectra, three emission bands （λ1 = 421 nm, λ2 = 380 nm, λ3 = 350 nm） were observed: the intensity of low energy emission band is reduced and that of the high energy is enhanced with the increasing dopant Ag; on the contrary, the intensity of low energy emission band is enhanced and that of the high energy one is reduced with the increasing dopant Mg.

关键词： thermoluminescence spectra borate lithium

Ability of Agrogyron elongatum to accumulate the single metal of cadmium, copper, nickel and lead and root exudation of organic acids

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2001年第3期13卷 368-375页

作者： YANG Hong 1, Jongathan W.C.Wong 2, YANG Zhi min\+1, ZHOU Li xiang 1(1. college of science, Nanjing agricultural university, Nanjing\ 210095, china. 2. Department of Biology, Hong Kong Baptist university, china) college of science Nanjing Agricultural University Nanjing 210095 China.

Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Ph in a greenhouse for a 9 - day. Cd, Cu, Ni and Ph generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Ph at 0.05 and 0.5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Ph was absorbed and accumulated to the highest level, with the concentrations of 92754 mg/kg dry weight (DW) in roots and 11683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for roots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Ph and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongation had the highest Ni concentration in shoots (30261 mg/kg DW) at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni > Cu > Ph > Cd (mg/kg DW), and those in roots were Ph > Cd > Ni > Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing root exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb, a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities, of citric acid were. found. However, no correlation between alternations in root exudation of organic acids and metal accumulation could be established.

关键词： heavy metal organic acid Agrogyron elongation hyperaccumulation

The Smoothness of Scattering Operators for Sinh-Gordon and Nonlinear Schrodinger Equations

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2002年第3期18卷 549-564页

作者： Bao Xiang WANG Department of Mathematics, hebei university. baoding 071002. P. R. china Department of Mathematics Hebei University Baoding 071002 P. R. China

We show that the scattering operator carries a band in H^s (R^n)×H^(s-1)(R^n) into H^s (R^n)× H^(s-1)(R^n) for the sinh-Gordon equation and an analogous result also holds true for the nonlinear Schrdinger equation with an exponential nonlinearity, where s≥n/2 is arbitrary and n≥2. Therefore, the scattering operators are infinitely smooth for the above two equations.

关键词： Sinh-Gordon equation Nolinear Schrodinger equation The smoothness of scattering operator

Extended detection range for an optical enzymatic glucose sensor coupling with a novel data-processing method

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2010年第6期53卷 1385-1390页

作者： GUO GuangMei1,WANG XuDong2,ZHOU TingYao2 & CHEN Xi2 1college of sciences,hebei university of science and Technology,Shijiazhuang 050018,china 2Department of Chemistry,college of Chemistry and Chemical Engineering,Xiamen university Key Laboratory of Analytical sciences of Xiamen university,Xiamen 361005,china 1. college of sciences Hebei University of Science and Technology Shijiazhuang 050018 China2. Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Key Laboratory of Analytical sciences of Xiamen university Xiamen 361005 China

A new data-processing method was established and applied for optical enzymatic glucose sensing,in which oxygen and glucose were simultaneously *** oxygen level remaining in the detection system,which was equal to the difference between the initial and consumed oxygen concentrations,could be measured using fluorescent oxygen indicators immobilized in the sensing *** was deduced that the ratio of I0 and I was inversely proportional to glucose concentration,where I0 is the maximum fluorescence intensity in various glucose solutions,and I is the fluorescence intensity at various concentrations of *** the new data-processing method,the detection range of the calibration curve method was extended from 0 to 1.2 mmol L-1,which was enlarged about 2–3 folds over that in ordinary *** prepared glucose sensor could be directly applied to detect high concentrations of glucose.

关键词： optical glucose sensor glucose oxidase extended detection range