RADIATION DEGRADATION OF CHITOSAN IN THE PRESENCE OF H2O2

INTRODUCTIONChitosan, poly-β-(1 -?4)-D-glucosamine, can be obtained from chitin by deacetylation with alkali. It is soluble indilute acidic medium due to the presence of amino groups. The use of chitosan in many areas, such as foodprocessing, biochemistry, Pharmaceuticals, medicine, and agriculture has been developed over the pastdecades[1,2].In recent years, it has been reported that many properties of chitosan depend on the molecular weight[3]. Thechitosan oligomers possess better fun…     

THE STRUCTURE OF N-METHYL-CINNOLINE TCNQ_2 I.THE STRUCTURE OF 2N-METHYL-CINNOLINE TCNQ_2

<正> M =553.6 triclinic Pl a=7.5701(9), b=7.5987(1), c=13.0327(13)A; α=86.923(10)°, β=80.921(9)°, γ=69.393(10)°, V=692.92(15)A3, Z=1; μ(MoKα= 0.79cm-1 F(000)=284.92,room temperature. The final R=0.047 for 1736 independent reflections. Planar tetracyanoquinodimethane(TCNQ) stacks along b axis with the molecular planes nearly parallel to each other, and mixed with 2N-methylcinnoline(2N-MCi). The separations between TCNQs are 3.212A and 3.321 A. Two overlap types are quite different. One is of ring external bond overlap, while the other has hardly direct overlap. This feature of 2N-MCiTCNQ2 stacking is used to explain the semiconducting character of the title compound.     

DARZENS REACTION OF 2-CHLOROMETHYLBENZOXALINE

2-chloromethylbenzoxaline reacted with aromatic aldehydes in alkaline solution,giv-ing Darzens condensation product:2-aryl-3-benzoxalinyloxiranes.     

THE STRUCTURE OF N-METHYL-CINNOLINE TCNQ_2 II.THE STRUCTURE OF IN-METHYL-CINNOLINE TCNQ_2

<正> M =553.6, triclinic,Pl, a=6.5157(22), b=7.7153(14), c=13.9146(28)A; α=88.394(16)°, β=84.288(22)°, γ=78.749(22)°, V=682.62(30)A3, Z=1; μ(MoKα)= 0.80cm-1, F(000)=284.92, room temperature. The final R=0.0537 for 1230 independent reflections. Planar tetracyanoquinodimethane(TCNQ). stacks along a axis with the molecular planes parallel to each other. The separations between TCNQs are 3.2698 and 3.2448. The overlaps of TCNQs are of the ring-external bond type. This mode of TCNQ stacking is used to explain the conductivity of the title compound. The D.C. conductivity along needle axis is σ(RT)=10(Ωcm)-1 1.     

KINETIC STUDIES OF CATALYTIC OXIDATIVE COUPLING OF METHANE ON SERIES OF LiMO_2 OXIDE

Using impregnation method, we synthesized several kinds of Li-doped transitionmetal oxide, LiMO_2 (M =Cr, Fe, Co, Ni, Zn and Al), as catalysts for the oxidativecoupling of methane. We found that the Fe-50 catalyst with 50/50 molar ratio ofLi_2O/Fe_2O_3, and Ni-20 with 20/80 molar ratio of Li_2O/NiO_x had high activity. At800℃, the coversion of methane on Fe-50 was 43. 2%, C_2 yield was 21.5%. Ni-20 was a little less effective, the methane conversion and C_2 yield were 34% and14. 5% respectively.     

STRUCTURE OF TERNARY COMPOUND LaNi_2Si_2

<正> The LaNi_2Si_2 alloy was prepared in a water-cooled copper crucible in an are melting furnace With a non-self-consume W electrode under an argon atmosphere. The pure components (La, 99.5%; Ni, 99.9%; Si, 99.99%) were used as raw materials. The alloy bulk was hongenized. The fine powder sample was used for X-ray diffraction after annealed in an evacuated silica tube at 400℃ in order to eliminate stresses.     

THE INFLUENCE OF N_2-O-2 AND He-O_2 SATURATION DIVING ON ELECTROENCEPHALOGRAM OF HUMAN BODIESS

This paper reports the changes of the EEG of human bodies during saturation ex-posure at different depths to different mixed gases. The results of the research show thatthe most obvious on EEG was the appearance of diffused slow waves, usually θ wavesof 4- 7 times/s, and δ waves of 2- 3 times/s within individual subjects. The EEG changesat 50 m were more obvious than those at 36 .5 m. With the prolonging of time under highpressure, the EEG had some improvements, for instance, the slow waves decreased andthe α waves increased. There was a certain relationship between these changes and thesymptoms which appeared in the human body. The chief factor of the EEG changes isdue to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. Inaddition, carbon dioxide retention under the high pressure is also a factor of the EEGchanges, because repeated inhaling of CO_2-dense mixtures could aggravate the EEGchanges and the reduction of carbon dioxide in humans by hyperventilation could improv     

CRYSTAL STRUCTURE OF OXAZOLIDINE-2-THIONE

<正> Crystals of. oxazolidine-2-thione, G3H5SNO, are triclinic,P1, a = 5.738(3), b = 5.928(4), c = 7.763(5) A, (?) = 83.05(6)°, α= 67.68(5)°, r = 77.85(5)°, Z = 2, V = 235.8A3, Dx = 1.45 g.cm-3, P(000) = 108, Mr = 103.14, m.p. = 96.2°-97.2°C, (MoK(?)) = 0.71069A, T = 293K, μ(MoK(?)) =0.051 mm-1. The structure was solved by direct methods and. difference Fourier synthesis. The final R was 0.033 for 655 unique observed reflections. It is a new hydrolysis and rearranging product of 2-hydryoxyl ethyl glucosinolate from the seeds of Copparis masaikai Levl.. The study of its physiological activity is in progress.     

ASYMMERIC SYNTHESIS OF 2-ARYLPROPIONIC ACIDS

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KINETIC ANALYSIS OF CO-CONDENSATION POLYMERIZATION OF AB2 AND AB MONOMERS

This work deals with the kinetics of co-condensation polymerization of AB2 and AB monomers, giving expressions of the two-dimensional molecular weight distribution function and the number/weight average molecular weights of the resulting copolymers. The two-dimensional molecular weight distribution depends on two indices, n and l, which are the respective numbers of AB2 and AB units in a copolymer species. The evolution of the two-dimensional weight and z distributions during the co-condensation polymerization has been evaluated systematically. Finally, the two-dimensional distribution was transformed into a one-dimensional molecular weight distribution with only one variable (the molecular weight of the products instead of the degree of polymerization). The calculated results show that the highly branched copolymer has a very broad molecular weight distribution when the co-condensation polymerization approaches completion.     

PROMOTION EFFECT OF KF ON THE BASIC PROPERTIES OF ZrO_2

ＰＲＯＭＯＴＩＯＮＥＦＦＥＣＴＯＦＫＦＯＮＴＨＥＢＡＳＩＣＰＲＯＰＥＲＴＩＥＳＯＦＺｒＯ＿２￥ＪｉａｎＨｕａＺＨＵ；ＨａｊｉｍｅＫＡＢＡＳＨＩＭＡ；ＨｉｄｅｓｈｉＨＡＴＴＯＲＩａｎｄＨｉｄｅａｋｉＩＴＡ（ＣｈｅｍｉｓｔｒｙＤｅｐａｒｔｍｅｎｔ，Ｎａｎ...     

ESR STUDY OF ZrO_2 CATALYST

ＥＳＲＳＴＵＤＹＯＦＺｒＯ＿２ＣＡＴＡＬＹＳＴ￥ＷｅｎＬＩ；ＬｉａｎｇＢｏＦＥＮＧ；ＹｕａｎＱｉＹＩＮ（ＬａｎｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｃａｌＰｈｙｓｉｃｓ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｌａｎｚｈｏｕ７３００００）...     

SYNTHESIS OF A 2-ARYLBENZOFURANOID DERIVATIVE

ＳＹＮＴＨＥＳＩＳＯＦＡ２－ＡＲＹＬＢＥＮＺＯＦＵＲＡＮＯＩＤＤＥＲＩＶＡＴＩＶＥＳＹＮＴＨＥＳＩＳＯＦＡ２－ＡＲＹＬＢＥＮＺＯＦＵＲＡＮＯＩＤＤＥＲＩＶＡＴＩＶＥ￥ＺｈａｏＨｕｉＹＡＮａｎｄＬｉａｎＮｉａｎｇＬＩ（ＩｎｓｔｉｔｕｔｅｏｆＭａｔｅｒｉ...     

APPLICATION OF 2D-NMR TECHNIQUES IN THE STRUCTURE DETERMINATION OF HYPODEMATINE

An alkaloid with a novel structure,named Hypodematine,was isolatedfrom Hypodematium sinense Iwatsuki(belonging to Thelypterdaceae).Itsstructure was elucidated by means of the ~1H-~1H COSY' ~1H-~(13)C COSY and long-range~1H-~(13)C COSY spectroscopy to have the skeleton of benzo-aza-cyclooctatetraenewith a phenyl substituent.Such basic structure has not been found in the na-tural product before.     

ACTIVATION OF O_2 AND CATALYTIC PROPERTIES OF CeO_2/CaF_2 CATALYSTS FOR METHANE OXIDATIVE COUPLING

The investigation of the catalytic properties of the CaF_2 modifiedCeO_2 catalysts for the methane oxidative coupling (MOC) to prepare C_2 hydro-carbons indicated that most of the CaF_2 modified CeO_2 catalysts were efficientfor the MOC reaction. Addition of CaF_2 to CeO_2 can make the C_2 selectivity in-crease from 2. 2％ (over CeO_2) to 46-63％, and the CH_4 conversion increasefrom 26％ to 28-30％. When the CeO_2 content was decreased within a defi-nite region, the activity and C_2 selectivity of the catalysts increased remark-ably. The XRD characterization revealed that F~-—O~(2-)exchange happened be-tween CaF_2 and CeO_2 phases. TPD, XPS, Raman and ESR experiments indicat-ed that O~-, O_2~(2-) and O_2~-species were formed over CeO_2/CaF_2 catalysts. Withthe increase of CaF_2 content in the catalysts, the kinds and the surface concen-trations of the above mentioned oxygen species decreased, while the C_2 selectivi-ty increased.     

PROPERTIES OF CHICKEN LIVER PHOSPHOFRUCTOKINASE-2

Phosphofructokinase-2 was purified to homogeneity from chicken livers by homogeniza-tion, polyethylene glycol fractionation and column chromatography on DEAE-Sephadex A-50 and Blue-Sepharose 4B. Some properties of the enzyme were as follows: (i) The saturation curve of the enzyme for fructose 6-phosphate showed hyperbolic and the Km of fructose 6-phosphate was affected by inorganic phosphate while Vmax was not; (ii) the binding of ATP to the enzyme was of negative cooperativity with a Hill coefficient of 0.56; (iii) the activity of the enzyme was completely lost in the presence of EDTA. The enzyme was activated by Mg2+ at low concentrations, but inhibited by Mg2+ at high concentrations; (iv) the enzyme was stable below 30℃ and easily lost its activity when the temperature was above 40℃; (v) the activity of the enzyme was stable at the range of pH 7-9, increased at pH 9.0-9.5 and decreased when pH was over 9.5; (vi) the enzyme was sensitive to trypsin and ATP protected the enzyme against the proteolysi     

CONSTRUCTION OF EQUILIBRIUM P-T BUNDLES OF COMBINATION OF n+2 PHASES ON PETROGENETIC GRIDS

This paper first discusses the algorithm for balancing reactions of the combination of n + 2 phases around an invariant point on a P-Tdiagram, and then emphatically develops a new algorithm for the arrangement of univariant reaction lines, using a signum matrix V·F or S·F, where V and S are diagonal matrixes of signum of △V and △S in n+2 univariant reactions respectively, and F is a signum matrix of stoichiometric coefficients of phases in reactions. Using this new algorithm greatly simplifies relative computer programs, brings out the automatic construction of equilibrium P-T curves of combination of n +2 phases, and further makes it possible to construct a whole petrogenetic grid automatically     

CHARACTERIZATION OF INTERMEDIATE IN HETEROGENEOUS HYDROGENATION OF CO_2 FOR ALCOHOL

The surface intermediates in hydrogenation of CO_2 to alcohol overRu-Cu heterogeneous catalyst are characterized with XPS and FT-IR tech-niques. The results show that there occur HCO_3, CO_3 and HCOO on catalystsurface and the intermediate HCOO forms in two ways: (1) With the promo-tion of lower valence copper, HCO_3 and/or CO_3 reacts with H_(a)~* formingHCOO; (2) CO_2 inserts directly into Ru(0)-H bond forming HCOO. The for-mation of the intermediates is related to H_(a)~*.     

AB INITIO STUDY OF LOW-LYING ELECTRONIC STATES OF THE AsH_2 RADICAL

The equilibrium geometries,excitation energies,force constants and vibrational frequencies for the low-ly-ing electronic states X ~2B_1,~2A_1,~2B_2 and ~2A_2 of the AsH_2 radical have been calculated at the MRSDCI level witha 3-21G~* basis set.Our calculated geometries,excitation enegies and vibional frequencies for theX ~2B_1 and ~2A_1 states are in good agreement with available experimental data.The electronic transition dipole mo-ments,oscillator strengths for the ~2A_1→X ~2B_1 and ~2A_2→X ~2B_1 transitions,radiative lifetimes for the ~2A_1 and~2A_2 states are calculated based on the MRSDC~1 wavefunctions,predicting results in reasonable agreement withavailable experiment.     

ELECTROFUSION OF IBRS2 CELLS AND THE STUDY OF THEIR FUSION PROCESS

IBRS2 epithelial cells in monolayer culture fused at a very high frequency when exposed to high-voltage electric pulsing fields. Exposure to four repetitive electric pulses of about 1.7 kilovolts per centimeter with a duration of 100 microseconds caused more than 90 percent of the cells to become fused (multinucleate) when 1 millimolar magnesium was present in the pulsing medium. Magnesium and calcium ions in the pulsing medium had a very strong effect on the electrofusion of IBRS2 cells. Magnesium could increase not only the electrofusion yield but also the stability of the cells under the conditions of electrofusion. In contrast, calcium inhibited electrofusion and decreased the stability of the cells. Careful microscopic observation revealed the electrofusion of IBRS2 cells to be very complex, dynamic process undergoing many interesting changes. A possible explanation for the process and mechanism of electrofusion of IBRS2 cells was proposed in agreement with the experimental observation.