Diterpenoid Alkaloids from Aconitum Pendulum

A new diterpenoid 12-epiacetyldehydrolucidusculline (1) and a new norditerpenoid alkaloid 2-hydroxydeoxyaconitine (2) were isolated from the roots of Aconitum pendulum, together with eight known alkaloids aconitine (3), deoxyaconitine (4), 3-acetylaconitine (5), 12-epiacetyldehydronapelline (6), dehydrolucidusculline (7), dehydronapelline (8). 12-epidehydronapelline (9), and noeline (10). The structures of the new alkaloids (1-2) were determined on the basis of spectral method.

SYNTHESIS OF N－ARYL－4－METHYLPHENOXYACETAMIDES BY MEANS OF LIQUID－LIQUID PHASE TRANSFER CATALYSIS

The title compounds 3a - 3n were prepared with high yields via the reaction of 4-methylphenoxyacetyl chloride with various substituted aromatic ammes under the condition of liquidliquid phase transfer catalysis using polyethylene glycol-400 as catalyst.

The Evolution of IR Spectra of H_2 Adsorbed on ZrO_2 with Changing Temperature（298－723K）

I.r.bands at 1559.0, 1441 .0, 1378 .9, 13603, 1031. 1,981 .4 and 947.3 cm -1 due tovarious types of dissociative adsorption of H2 over ZrO2 with changing temperatore wereobserved by in situ FT-IR spectroscopy.

Kinetic Study on Horseradish Peroxidase Interacting with Cyclodextrin

The catalyst reactivity of Horseradish peroxidase was enhanced in the presence of beta-cyclodextrin. During this course, beta- cyclodextrin played a role of stabilizing the intermediates of HRP. The results have been investigated using spectra and calculation.

A New Triterpenoid Glycoside from Decaisnea Fargesii

A new triterpenoid glycoside, named decaisoside F. has been isolated from Decaisnea faresii. Its structure was determined on basis of chi mical method, FAB-MS. homonuclear and heteronuclear correlation esperiments. including H-1--(HCOSY)-H-1. H-1--C-13 COSY, TOSCY, HMBC and NOESY techniques to be 3-O-beta-D- xylopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-Larabinopyranosyl) hederagenin 28-O-beta-D-xylopyranosyl (1-->4)-beta-D-glucopyrancrsyl (1-->6)-beta-D-glucopyranoside.

Preparation and Characterization of Bonded Stationary Phase Containing Monoaza Crown Ether for High-Performance Liquid Chromatography

Silica gel bonded stationary phases containing monoaza crown ether was synthesized via a series of solid-liquid phase reactions. The bonded molecular structure was characterized by chemical and instrumental analyses. The bonded stationary phase was provided with complexing ability with copper ion as well as hydrophobic property. The chromatographic retention behaviours of some substituted polar phenol derivatives, organic acids and bases on the bonded stationary phase were studied using methanol and/or aqueous solution of dibasic potassium phosphate buffer as mobile phase. When copper ion was added to the mobile phase at pH 5.4, the retention of substituted phenols became strong.

THE SUPPORTED GOLD CATALYST FOR REMOVING CARBON MONOXIDE AT AMBIENT TEMPERATURE

The supported gold Catalysts have high activity, good resistance to moisture and sulfur poisoningfor removing carbon monoxide from air at ambient temperature.

PROPERTIES OF ULTRAFINE SnOx THIN FILM MADE BY PLASMA POLYMERIZATION

Abstract: Ultrafine SnOx thin films were prepared from tetrabtltyltin by RF glow dis charge polymerization. Annealing behaviour of films under air and gas-sensitive probesty were investigated. The ultrafine SnOx thin film with average part ide size of 6nm exhibited a high sensitivity of 30 to 500ppm EtOH at 200℃.

CATALYTIC PROPERTIES AND SURFACE STRUCTURE OF MgO PREPARED FROM VARIOUS PRECURSORS

The calalytic perfomlances and surface surface of MgO prepared from different precursors were studied using cataytic test and pulse reaction techniques It was indicated that the MgO prepared from Ma(OH)24MgCO36H2O pretreated with distilled water exhibited the highest activity foe the oxidative coupling of methane. High lattice oxygen mobility and strong surface basicity may favor the OCM reaction.

ESR DETECTION OF ACTIVE INTERMEDIATES PRODUCED BY VIOLOGENMEDIATED REDUCTION OF SUBSTITUTED NITROARENES

The active intermediates 'substituted aniline radicals' were detected by ESR method duringthe reduction of substituted nitroarenes in the presence of methylviologen (MV2+) as electron-transfer catalyst (ETC).

A Novel Condensation Reaction of Alkyl Aryl Ketone with Ethyl Ortho-Formate under Microwave Irradiation

Under microwave irradiation, boron trifluoride has been found to mediate a novel condensation reaction of alkyl aryl ketone with ethyl ortho-formate to give a series of new condensation products (5,6,7,8). Their structures were determined by IR, H-1/C-13-NMR, MS spectra, and the crystal structure of 8 was further defined by X-ray diffraction.

IR study of the interaction between graphite and PTFE during mixing process

ALONG with the development of various IR spectroscopic techniques, the feasibility of employ-ing IR spectroscopy to the surface study of condensed matter has been reported in recentyears. With a function of determining the chemical nature of surfaces and absorbents, IRspectroscopy is a very useful tool and maybe an indispensable tool to some extent for investigat-ing the vibration properties of surfaces. Unfortunately, the IR molecular vibration spec-

Effect of Ti Incorporation on the Microstructure and Properties of the a-C:H Films Deposited by Magnetron Sputtering Technique

Amorphous hydrogenated carbon(a-C:H)and Ti-incorporated a-C:H(Ti/a-C:H)films were deposited by magnetron sputtering with a mixture gas of CH4 and Ar.The effect of the Ti incorporation on the chemical composition,microstructure and properties of the as-deposited and the annealed films were investigated by various techniques.It has been shown that the bonding structure and the internal stress were sensitive to the incorporation of the Ti atoms.The results of the XPS revealed that the concentration of Ti atom on the surface of the film increased when the Ti/a-C:H film annealed at 300oC.The tribologcial properties of the(Ti/)a-C:H films changed greatly after annealed,due to the graphitization,oxidation of carbon,and so forth.It compared and discussed in detail the change of the microstructure and properties of the a-C:H and Ti/a-C:H films before and after

Friction effect on free volume in amorphous-crystal region of PTFE

POSITRON annihilation technique (PAT) is a sensitive probe to detect the size and concentrationof free volume holes. In recent years, it has been used to study the correlation between mi-crostructure and macroscopic properties of crystal polymers. Experimental results show thatthe polymers’ macroscopic properties, such as mechanical properties, thermal properties andstructural phase transition, can be reflected by the change of free volume. It

Study on the Tribological Properties of Graphite-like Amorphous Carbon Film under Different Testing Conditions

Graphite-like amorphous carbon film was fabricated by unbalanced magnetron sputtering technique.Raman spectroscopy,atomic force microscopy(AFM)and tribometer were subsequently used to investigate the microstructure and tribological properties of the resultant film.It is found that the deposited carbon film is dominated by sp 2 sites,and the intensity ratio of the D and G peaks is as high as 4.0,which is one order of magnitude larger than that of diamond-like carbon films with high sp 3 content,indicating a more graphite-like structure.However,the as-deposited carbon film exhibits moderately high hardness(13.7 GPa),low internal stress(0.38 GPa)and superior tribological properties with high load bearing capacity(Hertz contact stress about 3.2 GPa)and low wear rate(2.73×10-10 cm3/N.m)in ambient atmosphere.Although it displays a poor wear resistance in water lubricated condition,a superior wear resistance is achieved in oil lubricated condition.Its inherent physical property,the formation of transfer layer and the friction induced chemical reactions may be commonly responsible for its tribological properties.

Phase and Microstructure Properties of Laser Cladding NiAl Intermetallic Compound Coating at Elevated Temperature

The phase and microstructure properties of laser cladding single phase NiAl coating at elevated temperature of 800 °C were investigated by means of XRD,SEM,and HRTEM.It was found that Ni3Al phase with a fine equiaxial microstructure precipitated along NiAl grain boundaries via the solid-state diffusion of Ni atoms during heating process.NiAl and Ni3Al phases have a common<110>zone axis.The phase and microstructure evolutions of NiAl during heating process can acquire well understand the diffusion behavior of laser cladding NiAl intermetallic compound coating and provide better guidance on its production and practical use.

Syntheses of a new type of chiral phosphines from glucose

Methyl 3-deoxy-3-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (1) and methyl 2-deoxy-2-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (2) were prepared from methyl 2,3-anhydro-4,6-O-benzylidene-O-D-mannopyranoside and methyl 2,3-anhydro-4,6-O-benzylidene-alpha-D-allopyranoside, respectively, via regioselective and stereospecific ring-opening reactions in high yields. Compounds 1 and 2 were oxidized to give the corresponding phosphine oxides (3 and 4).

Property of alumina to adsorb long chain normal-paraffinhydrocarbons

That alumina can strongly absorb long chain normal_paraffin hydrocarbon was found when alumina was used in the preparative group_type separation of heavy petroleum fractions. The reason for the above property of alumina may be that the normal_paraffin hydrocarbons can extend closely on the alumina surface. One molecule of long chain normal_paraffin hydrocarbon can be adsorbed by many active sites of alumina surface. The longer chain normal_paraffin hydrocarbon can be adsorbed by more active sites of alumina surface; this results in the longer chain normal_paraffin hydrocarbon has a stronger adsorption on alumina.