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A　NEW　INGENOL　ESTER　FROM　EUPHORBIA　PETIOLATA

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Chinese Chemical Letters 1996年第5期7卷 439-440页

作者： Shi, YP Ma, B j.a, Zj.Lahham, j.saleh, sa LANZHOU UNIV INST ORGAN CHEMSTATE KEY LAB APPL ORGAN CHEMLANZHOU 730000PEOPLES R CHINA

Abstract: A new monoester of the tetracyclic diterpene ingenol was isolated from Euphorbia petiolata and its structure was elucidated by spectroscopic methods and chemical transformationas ingenol-3-O-(2'E, 4'Z)-tetra...

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Pharmacological effects of aqueous-ethanolic extract of Hibiscus rosasinensis on volume and acidity of stimulated gastric secretion

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Asian Pacific j.urnal of Tropical Medicine 2011年第11期4卷 883-888页

作者： Raj.sh j.Mandade sa Sreenivas DM sakarkar Avij.t Choudhury Pharmacology Department S.N.Institute of PharmacyPusadIndia Guru Nanak Institute of Pharmacy IbrahimpattnamHyderabad.(A.P.) India S.N.Institute of Pharmacy PusadIndia Pharmacology Department Shree Dhanvantary college pharmacyKimIndia

Obj.ctive:To explore the effects of extract of Hibiscus rosasinensis(***) on the volume,free and total acidity of gastric secretion induced by ***:Animals were kept on fasting for 48 *** the pylorus of each animal was *** were randomly divided into 5 groups and treated by carbachol at 600μg/*** animals in groupⅡ-Ⅴwere treated by *** extract at 250 and 500 mg/kg body weight,cimetidine at 2.5 mg/ kg and verapamil at 10 mg/kg body weight intraperitoneally,*** volume,free and total acidity of gastric secretion were observed and ***:It was found that the extract significantly reduced the volume,free and total acidity of gastric secretion(P<0.01). These reductions were comparable to cimetidine and *** the reduction in the volume and free acidity were more significant in cimetidine and verapamil treated group indicating that cimetidine and verapamil were more ***:The extract of *** can reduced the volume,free and total acidity of gastric secretion,and can be used effectively in the treatment of peptic ulcer.

关键词： Verapamil Cimetidine Carbachol Hibiscus rosasinensis Rats

Improvement in varistor properties of CaCu_(3)Ti_(1)O_(12) ceramics by chromium addition

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j.urnal of Materials Science & Technology 2020年第6期41卷 12-20页

作者： Edson Cezar Grzebielucka j.ao Frederico Haas Leandro Monteiro Eder Carlos Ferreira de Souza Christiane Philippini Ferreira borges AndréVitor Chaves de Andrade Eloísa Cordoncillo Héctor Beltrán-Mir sandra Regina Masetto Antunes Programa Pós-Graduacao em Química Aplicada Universidade Estadual de Ponta GrossaAv.Gen.Carlos Cavalcanti 474884.030-000Ponta GrossaParanáBrazil Programa de Pós-Graduacao em Ciências/Física Universidade Estadual de Ponta GrossaAv.Gen.Carlos Cavalcanti 474884.030-000Ponta GrossaParanáBrazil Dpto.de Química Inorgánica y Orgánica Universitat Jaume IAv.de Vicent Sos Baynats/n12071Castellón de la PlanaSpain

The effect of chromium addition on the structure and electrical properties of CaCu3Ti4O12 is *** based on the formula CaCu3Ti4-xCrxO12-σ(x = 0, 0.025, 0.050 and 0.075 mol%) are prepared by solid-state reaction. Pellets sintered at 1070℃ for 12 h are characterised by X-ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and impedance spectroscopy. Current densityelectric field, dielectric loss and permittivity measurements are also carried out. Rietveld refinement showed the substitution of Cr(Ⅲ) on the Ti(Ⅳ) site, with the maximum substitution for x = 0.025 mol%.The generation of electrical defects in the grain boundary region by chromium doping is responsible for increasing the electric breakdown field strength and nonlinearity coefficient at room temperature from 1723 V/cm and 5.29 for x = 0 mol% to 3431 V/cm and 8.16 for x = 0.025 mol%. This composition shows the greatest improvement in ceramic varistor parameters.

关键词： CCTO Structural analysis Impedance Varistor Rietveld

Titrimetric Study of the Solubility and Dissociation of Benzoic Acid in Water: Effect of Ionic Strength and Temperature

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American j.urnal of Analytical Chemistry 2015年第5期6卷 429-436页

作者： sa'ib j. Khouri Department of Basic Sciences American University of Madaba Madaba Jordan

The apparent acid dissociation constant (Kc) of benzoic acid in water has been determined ti-trimetrically under ionic strength values between 0.00 and 0.50 mol·L﹣1 at a range of temperatures between 16°C and 41°C. The thermodynamic dissociation constant (as pKa) of benzoic acid was determined as 4.176 at 25°C. No regular correlation between pKa of benzoic acid and the temperature in the range was used. The values of pKa are inversely proportional to temperatures between 16°C and 30°C. In this range of temperature, the values of thermodynamic quantities () for the dissociation process of benzoic acid in water were calculated by using Van’t Hoff plot. For this case the dissociation was not favoured through entropy and enthalpy changes. The values of pKa are directly proportional to temperatures between 30°C and 41°C.

关键词： Benzoic Acid Ionic Strength Thermodynamic Dissociation Constant salt Effect

Automated tree detection and crown delineation using airborne laser scanner data in heterogeneous East-Central Europe forest with different species mix

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j.urnal of Forestry Research 2017年第5期28卷 1049-1059页

作者： Róbert Smreek Ivan sakov Zuzana Michnová j.n Tuek Department of Forest Management and Geodesy Technical University in Zvolen Department of Forest Policy Economics and Forest ManagementNational Forest Centre-Forest Research Institute Zvolen

Identifying tree locations is a basic step in the derivation of other tree parameters using remote sensing techniques, particularly when using airborne laser scanning. There are several techniques for identifying tree positions. In this paper, we present a raster-based method for determining tree position and delineating crown coverage. We collected data from nine research plots that supported different mixes of species. We applied a raster-based method to raster layers with six different spatial resolutions and used terrestrial measurement data as reference data. Tree identification at a spatial resolution of 1.5 m was demonstrated to be the most accurate, with an average identification ratio (IR) of 95% and average detection ratio of 68% being observed. At a higher spatial resolution of 0.5 m, IR was overestimated by more than 600%. At a lower spatial resolution of 3 m, IR was underestimated at less than 44% of terrestrial measurements. The inventory process was timed to enable evaluation of the time efficiency of automatic methods.

关键词： Airborne laser scanning East-Central Europe Individual tree Mixed forest Tree crown delineation

Synthesis,Structures,and Fluorescence Property of a Novel Heterometallic Complex Constructed by Imidazole

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Chinese j.urnal of Structural Chemistry 2020年第5期39卷 942-948页

作者： LI sa-Ying Department of Chemistry Chemical Engineering Shaanxi Xueqian Normal UniversityXi'an 710100China

A novel heterometallic complex constructed by imidazole ligand,CoZn(C3N2H3)4(1),has been synthesized under hydrothermal *** 1 was characterized by IR spectra,thermal analysis,powder X-ray diffraction and single-crystal X-ray ***-crystal X-ray diffraction studies reveals that compound 1 is in the tetragonal system,space group I41cd with a=23.4371(5),b=23.4371(5),c=12.4430(7)?,V=6834.9(4)?3,Z=16,C12H12CoN8Zn,Mr=392.60,Dc=1.526 g/cm^3,F(000)=3152,μ=2.381 mm–1,R=0.0323 and w R=*** CoZn(C3N2H3)4 is one-dimensional heterometallic molecular chains,which are further extended into a 3D open ***,the solid-state fluorescence property of the complex has also been investigated at room temperature.

关键词： heterometallic complex crystal structure fluorescence property

Circular Dichroism and Derivative Spectra Study of the Excitonic Aggregation of Pinacyanol by Aerosol-OT

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Open j.urnal of Physical Chemistry 2012年第1期2卷 34-40页

作者： sa’ib j. Khouri Volker Buss Department of Chemistry American University of Madaba Madaba Jordan

Different structures are proposed for the complexes formed from the interaction between the cationic cyanine dye 1, 1’-diethyl-2, 2’-carbocyanine chloride (Pinacyanol chloride) and the anionic surfactant sodium bis (2-ethylhexyl) sul- fosuccinate (Aerosol-OT) in ethanol-water solutions. UV/vis and electronic circular dichroism (CD) spectra provide tools to study the concentration and solvent dependence of this interaction. The aggregation spectra of the dye are dominated by a strongly blue-shifted, sharp and single visible band, which appears at concentrations much below the critical micelle concentration (cmc) of Aerosol-OT. Above the cmc, the spectra in pure aqueous solution indicate disso- ciation into monomer and dimer species, and the system becomes completely empty of chirality. Two different CD spectra with a distinct isosbestic point are observed for complexes with different surfactant to dye ratios. Both the addi- tion of ethanol (more than 7.5%) and increasing the temperature retards the metachromatic process between the dye and Aerosol-OT. By using the peakFit program, the two overlapping excitonic absorption bands together with the optically inactive absorption band for one spectrum (the most optimal one) at a specific Aerosol-OT concentration were sepa- rated.

关键词： Cyanine Dye Pinacyanol Surfactant Aerosol-OT Aggregation Circular Dichroism Derivative Spectra

Interaction of cationic cyanine dye with algal alginates: evidence for a polymer bound dye dimer

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j.urnal of Biophysical Chemistry 2011年第4期2卷 380-385页

作者： sa’ib j. Khouri Volker Buss Department of Chemistry American University of Madaba Department of Chemistry University of Duisburg-Essen

Under certain conditions algal alginates bind pinacyanol chloride in the form of dimers – this is the conclusion drawn from a uv/vis and circular dichroism (CD) spectroscopic study of aqueous solutions of the dye in a 10-fold molar excess of the polysaccharide from different sources. With its easily detected features the dimer holds promise as a diagnostic tool for alginate conformational analysis. Binding of the strongly blue-shifted (maximum wavelength = 485 nm) dimer is probably mediated by the charged groups and involves guluronate units only. By using the peakFit program, the two overlapping excitonic absorption bands together with the optically inactive band resulted from the interaction of pinacyanol with a specific alginate concentration were separated. The standard Gibbs energy of the interaction was calculated as –27.02 ***–1. The dimers are sensitive against acid and divalent cations.

关键词： Guluronate Mannuronate Peakfit Association Constant Complexation Circular Dichroism

Synergic catalysis of W and Ni originating from substitution of trivacant phosphotungstate for the selective oxidation of aniline to azoxybenzene

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Chinese Chemical Letters 2024年第2期35卷 558-563页

作者： Sheng Cai Xiao-Yuan Wu Weiming Wu sa-sa Wang Can-Zhong Lu CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117China Xiamen Institute of Rare Earth Materials Chinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Partial substitution of polyoxometalate(POM)is an efficient route to modulate the catalytic property of maternal *** this work,a new Keggin type POM involving{Ni 6}cluster,{[Ni(H_(2)O)_(2)(Dach)_(2)][Ni(Dach)_(2)]_(2)}{[Ni_(6)Cl(μ-OH)_(3)(H_(2)O)(Dach)_(3)(WO_(4))(PW9 O_(3)_(4))][Ni_(6)(μ-OH)_(3)(H_(2)O)_(2)(Dach)_(3)(WO_(4))(PW9 O_(3)_(4))]}Cl·27H_(2)O,(1,Dach=1,2-diaminocyclohexane)was *** 1 shows excellent catalytic performance in the selective oxidation of aniline to azoxybenzene(AOB)in *** apparently different results from that with the matrix{PW_(9)O_(34)}({PW9})suggest the successful regulation of the catalytic property of{PW9}by the introduction of the{Ni6}cluster into the *** experimental results indicate that the highlighted performance of 1 is contributed by the synergy of W and Ni sites,which are respectively responsible for the oxidation and condensation steps in the production of *** good selectivity to AOB is essentially attributed to the effective modulation of the reaction rates of oxidation and condensation steps by W and Ni sites,respectively.

关键词： Polyoxometalate {Ni_(6)}cluster Modulated catalytic property Aniline oxidation Azoxybenzene