Table of Content

30 December 2000, Volume 20 Issue 04 Previous Issue    Next Issue

研究报告

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STUDY ON AMINO POLYESTER BAKING VARNISH MODIFIED BY TUNG OIL SHANG Shi-bin;XIE Hui;HUANG Huan;WANG Ding-xuan 2000, 20 (04):  1-5.  Abstract ( 630 )   PDF (686KB) ( 957 )   Save Amino polyester baking varnishes modified by tung oil were made from polyhydroxyl esters which were synthesized from methyl α eleostearate maleic anhydride adduct crosslinked by amino resins. Effects of each component, the ratio of components and the curing condition on their properties were discussed. The IR spectra were also studied. By performance testing, it has been confirmed that these varnishes possessed good properties and could be used as amino coatings. Related Articles | Metrics

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INHIBITORY EFFECTS OF DIFFERENT FRACTIONS OF BLACK WATTLE BARK TANNINS ON HYDROLASES YAO Kai;Lü Yuan-ping;SHI Bi;HE Qiang 2000, 20 (04):  6-10.  Abstract ( 483 )   PDF (685KB) ( 770 )   Save Tannin fractions with different molecular weight distributions were obtained by purification of alcohol preci pitation and fractionation of solvent extractions of black wattle bark tannins. The data observed in the experiments indicated that tannin fractions possess varying inhibitory effects on activity of hydrolases, showing selective inhibition. Based on comprehensive investigations of cellulase, it was displayed that the inhibitions are related to the inhibitor constant Ki. When the molecular weight of the fractions is higher, Ki value is lower and the inhibitory effect is stronger. Meanwhile, the inhibition of the fractions on the cellulase was proved to be a noncompetitive one. Related Articles | Metrics

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STEADY STATE COMPUTER SIMULATION OF PULPING PROCESS HU Mu-yi;WANG Shui-liang;HU Ming;CHEN Zhao-xia;ZHAO Shu-lei 2000, 20 (04):  11-14.  Abstract ( 626 )   PDF (464KB) ( 525 )   Save Computer simulation of pulping and papermaking process in the fields of production, scientific research and education has been extensively used in developed countries. It has become an important tool to analyse and solve the problems concerning pulping and papermaking. Based on Chinese domestic situation,a software of steady state pulping process simulation system was developed by the authors.It can be used for calculation and analysis of pulp mill design, as well as for inspection and control of practical production in the mill. Related Articles | Metrics

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STUDY ON THE OPTIMUM CONDITION FOR SINGLE STAGE OXYGEN DELIGNIFICATION OF MASSON PINE KRAFT PULP MA Yong-wen;CHEN Chang-hua;CHEN Zhong-hao;LI Xing-ping;SONG Bing-zhang 2000, 20 (04):  15-19.  Abstract ( 662 )   PDF (907KB) ( 494 )   Save The optimum conditions for single stage oxygen delignification of masson pine kraft pulp had been studied at oxygen pressure 0.6MPa, NaOH charge 5%, MgSO4 charge 0.5%, pulp consistency 10%, cooking temperature 100℃ for 80 min to obtain the results as follows: delignification rate 47.1%, pulp viscosity 948.1 cm3/g, pulp brightness 41.0%(ISO), yield 96.9%, breaking length of pulp 6.3km, burst index 5.8kPa·m2/g, tear index 14.1 mN·m2/g. Related Articles | Metrics

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NEW TECHNOLOGY OF CATALYTIC SYNTHESIS OF DIHYDROMYRCENOL FROM PINANE MAO Li-qiu;YIN Du-lin;LI Qian-he;GUO Jian-ping 2000, 20 (04):  20-24.  Abstract ( 1213 )   PDF (691KB) ( 865 )   Save Dihydromyrcene was obtained from cracking of cis pinane,followed by direct hydration of the crude products to prepare dihydromyrcenol. Catalytic cracking of pinane was obviously superior to thermal cracking. When cis pinane was converted completely, the selectivity of dihydromyrcene was over 50% while that of thermal cracking is much lower. The selectivity of direct hydration of dihydromyrcene catalysed by solid acid was 80%, It had advantages of few kinds of auxiliary materials, short production period, low consumption, low pollution, etc. Related Articles | Metrics

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STUDY ON AUTO-OXIDATION AND POLYMERIZATION OF METHYL ELEOSTEARATE XIA Jian-ling;HUANG Huan;WANG Ding-xian 2000, 20 (04):  25-29.  Abstract ( 722 )   PDF (878KB) ( 965 )   Save The oxidation results of methyl eleostearate in vessels of different kinds of materials were investigated. It was found that iron material had relatively strong ability of catalytic oxidation. The polymerization rules of methyl eleostearate were discussed, and the proper conditions of dimerization were also obtained. The proper reaction temperature was 260～270℃ and reaction time was 5～8h. Related Articles | Metrics

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A STUDY ON ULTRAFILTRATION FLUX OF XYLAN JIANG Hua;XU Yong;YONG Qian;YU Shi-yuan 2000, 20 (04):  30-34.  Abstract ( 641 )   PDF (660KB) ( 583 )   Save Experimental study was carried out on ultrafiltration flux of xylan solution derived from alkali extraction of corncob through different membranes. It was shown that solvent flux was increased with the enchanced operating pressure through PLGC and PLCC membrane, but the proper operating pressure should not exceed 100 kPa with PLGC membrane. Feed velocity has more pronounced effect on solvent flux through PLGC membrane than through PLCC.Relations between feed concentration and solvent flux followed the membrane model. Solute concentration on membrane was affected by operating conditions and membrane cutoff molecular weight. The influence of operating parameters on flux was investigated by means of uniform design test, and results showed that feed velocity is the most critical factor to control flux with membrane of high molecular weight cutoff(PLGC), and operating pressure is the most critical factor to control flux with membrane of low molecular weight cutoff (PLCC). Meanwhile, relations between solvent flux through two kinds of membrane and operation parameters were correlated, and the values calculated from the two sets of correlation were in good agreement with those obtained from experiment at relative error 7%. Related Articles | Metrics

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DEVELOPMENT OF THE AUTOMATIC CONTROL SYSTEM FOR BATCH DISTILLATION OF OLEORESIN ZHANG Shi-hua;CHEN Yan;ZHENG Shi-long;XIAO Yu-min 2000, 20 (04):  35-39.  Abstract ( 633 )   PDF (609KB) ( 576 )   Save This paper deals with the automatic control system for batch distillation of oleoresin by STD bus microcompu ter. Bases on analyzing the control schemes of system, the design methods of software and hardware,as well as the function and benefit accomplished by the system are described. Related Articles | Metrics

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STUDIES ON PURIFICATION OF ALKALI LIGNIN FROM RICE STRAW PULPING WITH ORGANIC SOLVENTS YANG Yi-qin;LI Zhong-zheng 2000, 20 (04):  40-44.  Abstract ( 679 )   PDF (828KB) ( 2223 )   Save Alkali-lignin from rice straw pulping was purified with organic solvents. Effect of different solvents and solvent dosage on yield and composition of purified lignin were investigated. The suitable solvent system and purifying conditions were determined. The results indicated: the optimum solvent system was a mixture of acetone and water(6:4,v/v), solvent to lignin ratio 10:1. Under this condition, yield of lignin was 85.20%, content of lignin increased from 31.13% to 44.86%, content of total sugar and ash in purified lignin were reduced 76.86% and 20.87%, respectively. Related Articles | Metrics

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MODIFICATION OF CELLULOSE MATERIALS BY ANTISEPTICS AND THEIR ANTIMICROBIAL PROPERTIES(Ⅱ)—Release of antiseptics from modified cellulose materials and their antimicrobial activity KOTELNIKOVA N E;HOU Yong-fa;PANARIN E F;KUDINA N P;LI Shu-xiu;ZAIKINA N A 2000, 20 (04):  45-49.  Abstract ( 650 )   PDF (729KB) ( 624 )   Save Dressing cellulose materials(CM) and bleached cotton cloth (CC) modified by surfactant antiseptics(CA) have been prepared by the method of adsorption interaction between CM and CA. Antiseptics release was studied by the method of desorption in solutions at different pH values. Maximum release of surfactants is achieved in solutions at pH=7.0 Microbiological tests of modified cellulose materials have shown that they exhibit antimicrobial activity. These results are valuable for practical application in clinics for imparting antimicrobial properties to dressing materials. Related Articles | Metrics

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PREPARATION OF HIGH-PURITY NEUTRAL XYLO-OLIGOSAC-CHARIDES ON POLYACRYLAMIDE COLUMN ZHAO Lin-guo;YU Shi-yuan;DING Yan 2000, 20 (04):  50-54.  Abstract ( 709 )   PDF (611KB) ( 552 )   Save The eluting orders of the main constituents in enzymatic hydrolysate of xylan on polyacrylamide column were studied,and the suitable elution flow rate and injection volume were determined.The results showed that protein and lignin were first eluted because of their highest molecular weight in hydrolysate.There were 12.8% acidic oligosaccharides in hydrolysate,eluted with the soluble xylan of DP>8 together.Using the proper elution flow rate and injection volume at 800mL/h and 120mL,respectively,high purity neutral xylo-oligosaccharides were rapidly isolated using 55cm×7.5cm polyacrylamide gel column,distilled water as flow phase,at 50℃. Related Articles | Metrics

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STUDY ON OPTIMUM CONDITION OF REACTION BETWEEN β-PINENE AND PARAFORMALDEHYDE CATALYZED BY ZnCl2 YI Feng-ping;KE Min;WANG Li-sheng 2000, 20 (04):  55-58.  Abstract ( 674 )   PDF (858KB) ( 939 )   Save Nopol was synthesized from β-pinene in turpentine and paraformaldehyde catalysed by ZnCl2. Uniform design was adopted to study reactant proportion, reaction time, reaction temperatrue which influence the yield of nopol. The experiment was arranged according to the optimum conditions from uniform design to obtain the actual yield at 71.31%, which is within the expected range and is superior to all other experiments. Related Articles | Metrics

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STUDIES ON GUM FROM SEEDS OF GLEDITSIA HETEROPHYLLA BUNGE JIANG Jian-xin;ZHU Li-wei;XU Jia-sheng 2000, 20 (04):  59-62.  Abstract ( 683 )   PDF (587KB) ( 1071 )   Save Polysaccharide is isolated and purified from seeds of G.heterophylla Bunge and its physiochemical properties are investigated.The purified polysaccharide is homogeneous.It is determined to be consisted of D-galactose and D mannose at ratio 1:3.2 with the chemical structure of β-(1,4)-linked D-mannopyranosy1 residues as the main chain and α-(1,6)-linked D-galactopyranosy1 residues in the side chain. Related Articles | Metrics

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PREPARATION AND CHEMICAL CONSTITUTION OF TEA PIGMENT Lü Hu;KONG Qing-you;LENG He-ping;HONG De-chen 2000, 20 (04):  63-68.  Abstract ( 784 )   PDF (829KB) ( 1408 )   Save Tea pigment is a water soluble colored substance, either contained in tea leaves, or derived from enzymatic/non enzymatic oxidative polymerization of tea extracts. According to their color, tea pigments can be classified into thearubigin, theaflavin and theabrowin. In this experiment, technological preparation of tea pigment from non enzymatic oxidation was carried out by adopting orthogonal test, to investigate the key technological factors. Chemical composition, molecular weight distribution and anti-oxidative activity of the product were also measured. Related Articles | Metrics

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STUDY ON THE SEPARATION OF 6-CHLORO-2-NITROTOLUENE MIXTURE LI Xiao-hua;YAO Ke-Jian;YU Feng-Wen;CHEN Ping 2000, 20 (04):  69-72.  Abstract ( 664 )   PDF (665KB) ( 573 )   Save Through distillation experiment, the process and parameters of separation of 6-chloro-2-nitrotoluene mixture have been studied in a φ26mm batch distillation column packed with high efficiency triangle metal packing of 900mm height, equivalent to 27 theoretical plates. The results showed that the purity of 6-chloro-2-nitrotoluene was over 96% by two tower distillation. Related Articles | Metrics

综述评论

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PYROLYSIS AND LIQUEFACTION OF BIOMASS YANG Min;SONG Xiao-rui;DENG Peng-fei;YANG Hui-rong 2000, 20 (04):  77-82.  Abstract ( 737 )   PDF (687KB) ( 1108 )   Save This paper introduces briefly the recent progress of research on pyrolysis and liquefaction of biomass. Methods to modify liquid product are described. Prospects of the research work in the future are also discussed. Related Articles | Metrics

研究报告

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ANALYSIS OF VOLATILE CONSTITUENTS IN YOUNG TWIGS OF PINUS TABULAEFORMIS LI Tie-chun;HOU Dong-yan;ZHANG Wei-hua 2000, 20 (04):  73-76.  Abstract ( 618 )   PDF (649KB) ( 643 )   Save In this paper,steam distillation was adopted to separate the volatile constituents from young twigs (songbitou) of Pinus.tabulaeformis growing in Mountain Qianshan of Liaoning Province.Chemical constituents of the volatile oil were identified by GC/MS method, and 25 constituents were identified.Yield of the volatile was approximately 2.1%. Related Articles | Metrics