SYNTHESIS AND CHARACTERISTIC OF POLYSILANES CONTAINING Si-H BOND

Three kinds of polysilanes containing Si-H bond, ■CH_3SiCH_3■_x■CH_3SiH■_y■_n and■PhSiPh■_π■CH_3SiH■_y■CH_3SiCH_3■, have been synthesized. The structures of these copolymers were investigated by IR, ~1H-NMR and ^(13)C-NMR and their molecular weights were measured.

Effects of docosahexaenoic acid or arachidonic acid supplementation on gene expression and contractile force of rat cardiomyocytes in primary culture

While fatty acids play essential roles in the physiology of the myocardium,conventional culture media contain little lipid.We previously revealed that rat neonatal myocardium mainly contains docosahexaenoic(DHA),linoleic(LA),and arachidonic(AA)acids as polyunsaturated fatty acids(PUFAs),and these contents in cultured cardiomyocytes derived from fetal rats were markedly lower than those in the neonatal myocardium.In this study,we first assessed the effects of supplementation of DHA,LA,or AA on the fatty acid contents and the percentage change of contractile area in primarily cultured rat cardiomyocytes.Based on this assessment,we then evaluated the effects of DHA or AA supplementation on mRNA expression and further directly measured the contractile force of cardiomyocytes with the supplementations.This study revealed that percentage change of contractile area was maximized under 20μM DHA or 50μM AA supplementation while LA supplementation did not affect this contraction index,and that a widespread upregulation tendency of the mRNA expression related to differentiation,maturity,fatty acid metabolism,and cell adhesion was seen in the cultured cardiomyocytes with supplementation of DHA or AA.In particular,upregulation of the gene expression of cellular adhesion molecules connexin43 and N-cadherin were remarkable,whereas the effects on differentiation and maturation were less pronounced.Correspondingly,the increase of the percentage change of the contractile area of cardiomyocyte clusters in culture dishes with the supplementations was significant,whereas the enhancement of the contractile force was modest.These results suggest that supplementation of DHA or AA to the fetal cardiomyocyte culture may play effective roles in preventing the de-differentiation of the cardiomyocytes in culture and that the enhancement of the contractile performance may be mainly attributed to the improvement of intercellular connection.

SYNTHESIS OF THE COPOLYMERS OF p-DIETHYNYLBENZENE WITH OTHER ACETYLENIC DERIVATIVE S INITIATED BY (Ph_3P)_2 PdCl_2

The copolymerization of p-diethynylbenzene (PDEB) with phenylacetylene (PhA), 4, 4'-diethynylbiphenyl (DEBP)or m-diethynylbenzene (MDEB) are studied by varying mole ratios of monomers. When the mole ratios of PDEB/PhA are less or equal to 1/5, the copolymers are soluble and fusible, but the other copolymers are insoluble and infusible. The results show that the good solvent of cross-linked copolymers is benzene and their solubility parameter is 9.15 cal^(0.5).cm(-1.5). And their swellability (θ_p), Huggins parameter (χ), density (d_4^(25)) and the average molecular weights between crosslinks (c) are measured. It is found that θp and c of copolymers are greater but d_4^(25) is less than that of respective homopolymers. IR spectra show that the copolymers have transoid configuration and small number of unreacted ethynyl groups exist in the copolymers. The mechanism about the polymerization or acetylenic derivatives initiated by (Ph_3P)_2PdCl_2 is discussed.

Hydrogen Absorption of Nd-Fe-B Alloys

The technical parameters of HD process were studied, including the effects of temperature and neodymium contents on the incubation period of hydrogen absorption, hydrogen concentration and the rate of hydrogen absorbed. The results show that the incubation period is shortened and the rate of hydrogen absorbed is accelerated with rising temperature and surface area. These are attributed to the rising rate of hydrogen diffusion at higher temperature. The change of the incubation period and the rate of hydrogen absorbed have the similar trend resulted from the increasing content of the Nd-rich phase owing to the rising temperature. Moreover, the percent of the Nd-rich phase in the ingot can be calculated according to the total hydrogen weight gain.

Design of biomimetic camouflage materials based on angiosperm leaf organs

The micro structures and reflectance spectra of angiosperm leaves were compared with those of angiosperm petals. The study indicated that angiosperm leaf organs had identical micro structures and reflectance characteristics in the wave band of near infrared. Micro structures and compositions of leaf organs were the crucial factors influencing their reflectance spectra. The model of biomimetic materials based on angiosperm leaf organs was introduced and verified. From 300 to 2600 nm, the similarity coefficients of reflectance spectra of the foam containing water and Platanus Orientalis Linn. leaves were all above 0.969. The biomimetic camou- flage material exhibited almost the same reflectance spectra with those of green leaves in ultraviolet, visible and near infrared wave bands. And its "concolor and conspectrum" effect might take on reconnaissance of hyperspectral and ultra hy- perspectral imaging.

Preparation of titanium phosphate white pigments with titanium sulfate and their powder properties

Titanium oxide that has photocatalytic activity is used as white pigment for cosmetics.A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight.In this work,as novel white pigment,titanium phosphates were synthesized with titanium sulfate and phosphoric acid for cosmetics.Their chemical composition,powder properties,photocatalytic activity,color phase,moisture retention,and smoothness were studied.These titanium phosphates had less photocatalytic activity to protect the sebum on the skin.Samples without heating and those heated at 100℃showed high reflectance in the range of visible light.Sample prepared in Ti/P=3/2 had higher moisture retention than samples prepared in other Ti/P ratios.

Ultrasonic synthesis of poly(2-methoxy-5-butoxy) phenylene vinylene

A new method was developed using ultrasonic irradiation to synthesize poly(2-methoxy-5-butoxy) phenylene vinylene from p-methoxy phenol (MOPh) and CH3 (CH2)3Br. Ultrasonic irradiation catalyzes the reactions through three major steps of etherification, bischloromethylation and elimination. Results showed that our ultrasonic irradiation method could significantly enhance production yield and reduce process time of the synthesis compared with reflux agitating method.