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Application of Experimental Design to Optimizing the Medium of Nuclease P1 XU Zheng-jun; XIAO Lin-ping;LU Hao;XIE Ning-chang; YING Han-jie    2003, 3 (5): 0-0.   Abstract （4511）      PDF （65KB）（1601）       Knowledge map    Save Experimental design was employed to study the effects of several factors on the production of nuclease P1 by Penicillium citrinum M02, such as carbon source, nitrogen source, phosphor source and corn steep liquor which acted as complementary nitrogen source. The results of two experiments showed that corn steep liquor could remarkably promote the production of nuclease P1. In addition, one model that can describe the fermentation perfectly was gained from these experiments. When nuclease P1 was produced on the optimized medium calculated from this model, its yield was 648.3 U/ml that is comparable with 661 U/ml from the model. And it is improved by 70% compared with the 380 U/ml, which was gained on the original medium at the same time. The possible reason for corn steep liquor promoting nuclease P1 fermentation is that corn steep liquor contains more useful amino acids such as glycin, alanine, serine and so on. Related Articles | Metrics

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Review on Facilitated Transport in Fixed Site Carrier Membranes SHI Wei; ZHANG Feng-bao; ZHANG Guo-liang; ZHANG Gang    2003, 3 (5): 0-0.   Abstract （4493）      PDF （236KB）（1640）       Knowledge map    Save Facilitated transport membrane with fixed site carriers is an attractive topic in the separation of gas and liquid mixtures because it is capable of increasing permeability and permselectivity simultaneously. In this paper, the mechanism of facilitated transport in fixed carrier membranes is addressed, the methods of carriers fixation are discussed and the problems to the development of the membrane process are summarized. In addition, the prospect of facilitated transport in fixed carrier membranes is previewed. Related Articles | Metrics

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Experimental Observation on Cellulosic Biodegradation in Solid State Fermentation ZHOU Xiao-hong; CHEN Hong-zhang; LI Zuo-huo    2003, 3 (5): 0-0.   Abstract （4284）      PDF （132KB）（1657）       Knowledge map    Save Expression of human Pro-urokinase gene in Pichia pastoris and the influence of main variables on the production and expression of Pichia pastoris were investigated. pH in the growth phase was 5.6, pH in the expression phase was 6.0, and the temperature was always 28oC. It is found that there exists clear corresponding between the AOX and Pro-UK production in the fermentation process, and a new procedure by feeding methanol and glycerol alternatively was proved to be effective in improving the enzyme activity of Pro-UK in the fermentation broth. Related Articles | Metrics

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Cultivation of Dunaliella salina in an Airlift Photobioreactor HAO Jian-xin; CONG Wei; KANG Rui-juan; CAI Zhao-ling    2003, 3 (5): 0-0.   Abstract （4279）      PDF （164KB）（1652）       Knowledge map    Save The separation property of membrane is related to the aperture structure of the membrane. In this paper, the chitosan ultrafiltration (UF) membrane was immersed into a coagulation bath with proper concentration and temperature and its aperture structure was modified. The results showed that the retention rate of chitosan membranes increased by 83.7% after being treated by precipitation. The retention rate, flux and aperture structure of chitosan membranes were affected by temperature of the coagulation bath, concentration of gelating agents and time of immersion precipitation. It is necessary to select appropriate parameters to enhance the separation property of chitosan UF membrane. Related Articles | Metrics

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Phase Transition and Transition Temperature Hysteresis of VO2 Thin Film HU Zai-yong; XU Chu-shao; YANG Shao-li; CHEN Guang-bi    2003, 3 (5): 0-0.   Abstract （4212）      PDF （49KB）（2041）       Knowledge map    Save The VO2 thin film was prepared by the colloid method with industrial V2O5 as raw material. The properties of the VO2 film such as resistance abrupt drop temperature, phase transotion temperature hysteresis are examined. The results show that the VO2 thin film phase transition temperature is 35oC. Preparation method and substrate show greater effect on resistance abrupt change order, which can reach 2~3 order if common glass or quartz glass were employed in underlay by H2 reduction process, while it can reach 1.5~2 order of magnitude by N2 thermal decomposition. The resistance abrupt change order of magnitude is larger for VO2 film with quartz glass as substrate, the transition temperature hysteresis is 1~6oC, and closely related with the resistance abrupt change order, underlay, substrate and preparation method. Related Articles | Metrics

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Preparation of Mesopore Activated Carbon from Municipal Solid Organic Wastes XIE Li-ping; LIN Wei-gang; YANG Xue-min    2003, 3 (5): 0-0.   Abstract （4136）      PDF （346KB）（1669）       Knowledge map    Save In gaseous products of biomass steam gasification, there exist a lot of CO, CH4 and other hydrocarbons that can be converted to hydrogen through steam reforming reactions. There exists potential hydrogen production from the raw gas of biomass steam gasification. In the present work, the characteristics of hydrogen production from biomass steam gasification were investigated in a small-scale fluidized bed. In these experiments, the gasifying agent (air) was supplied into the reactor from the bottom of the reactor and the steam was added into the reactor above biomass feeding location. The effects of reaction temperature, steam to biomass ratio, equivalence ratio (ER) and biomass particle size on hydrogen yield and hydrogen yield potential were investigated. The experimental results showed that higher reactor temperature, proper ER, proper steam to biomass ratio and smaller biomass particle size will contribute to more hydrogen and potential hydrogen yield. Related Articles | Metrics

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Propagation and Decay of Concentration Wave in the Liquid–Solid Pulsed Fluidized Beds JIN Guo-dong; LIU Da-you; SHU Chi-wang    2003, 3 (5): 0-0.   Abstract （4088）      PDF （190KB）（1350）       Knowledge map    Save The propagation and decay of concentration wave in liquid–solid pulsed fluidized beds is studied by numerical simulation and experimental validation. When the semi-on period and semi-off period are much longer than the particle relaxation time, the difference between the inertia forces of the two phases is small compared with the gravity of the solid phases except a short period in the order of the particle relaxation time after a sudden change of fluidizing velocity, the momentum equations of the two phases in pulsed fluidized beds can be simplified to a local equilibrium model. The simulation difficulty caused by the ill-posedness of the basic two-fluid model can be avoided using the concentration wave equation. The liquid–solid flow pulsation induced by the fluidizing fluid varying in both sinusoidal and step-wise patterns is simulated using the five order WENO scheme for spatial derivative and three order TVD Runge–Kutta method for time derivative. The front-fixing method is used to handle the moving upper boundary. The simulation result of fluidizing velocity varying in step-wise pattern is validated and matches the experimental data well. In the pulsed fluidization, the concentration wave decays due to the interaction between the concentration discontinuity and dilatation waves. Related Articles | Metrics

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Preparation of Nanostructured Lipid Carriers Loaded with Retinoic Acid by the High Pressure Homogenization Method ZHANG Xiao-jia;XIA Qiang;MA Quan-hong;DUAN Lei;GU Ning    2005, 5 (1): 54-57.   Abstract （4081）      PDF （198KB）（757）       Knowledge map    Save The poor aqueous solubility and instability of retinoic acid (RA) have limited its clinical use. Solid lipid nanoparticles (SLN) have a potential limitation which is the drug expulsion. This study was undertaken to overcome the limitation by loading RA in nanostructured lipid carriers (NLC). RA-loaded NLC was prepared by high pressure homogenization and characterized by transmission electronic microscope (TEM), particle size analyzer, zeta potential analyzer and high-performance liquid chromatography (HPLC). The results were as follows: (1) When the homogenization cycle number varied from 1 to 12, the mean particle size decreased from 120 nm to 10 nm, while P.I. (polydispersity index) increased from 0.26 to 0.69. (2) The spherical shape observed by TEM indicated a better drug loading capacity over SLN. (3) The concentration of all-trans retinoic acid (ATRA) in NLC reached 56.26 g/mL compared to 20 g/mL dissolved in silicone oil and the photostability of ATRA was improved so that the effective concentration of RA could keep for a longer time. (4) As far as the stability of NLC was concerned, its potential value was ( 30.9 0.6) mV and it remained stable after 120 min centrifugation (4℃, 10000 r/min) or 6 month light-proof storage. Furthermore, freezing-drying ( 40℃, 0.01 Pa), which increased its mean particle size and reduced its P.I., could also be used to increase the NLC stability. Taken together, RA-loaded NLC is a promising drug form for clinical use. Related Articles | Metrics

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Characteristics and Formation Mechanism of Secondary Organic Aerosol BAI Zhi-peng;LI Wei-fang    2008, 8 (1): 202-208.   Abstract （4012）      PDF （237KB）（1541）       Knowledge map    Save The formation of secondary organic aerosol (SOA) is one of the research focuses in atmospheric chemical process. In urban atmosphere, secondary organic carbon constitutes about 17%~65% of the total particulate organic carbon. Monoterpene and aromatics are the most important natural and anthropogenic precursors of SOA, respectively. The volatile precursors react with atmospheric oxidants such as hydroxyl (×OH), nitrate radical (NO3-) and O3 through multiple reaction pathways, producing semi-volatile secondary organics including diacids, multifunctional carbonyls and nitrate organics, etc. Theses compounds can distribute into particulate phase via adsorption and absorption processes, and will alter the property and environmental effects of ambient aerosols. Organic molecular markers are utilized to apportion the sources of atmospheric ambient aerosols, and organic diacids are potential tracers for SOA. In this article, the advances and problems in SOA research are reviewed, and future research recommendations are presented. Related Articles | Metrics

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Activity Interaction Coefficients in Fe-C-N, Fe-C-V and Fe-C-V-N Melts CHEN Er-bao;WANG Shi-jun;ZHOU Yun;SONG Bao-guo    2005, 5 (5): 529-531.   Abstract （3838）      PDF （147KB）（682）       Knowledge map    Save The saturated solubility of carbon and nitrogen in Fe-C-N and Fe-C-V-N melts was measured experimentally at 1435℃. The purpose of present work is to obtain the activity interaction coefficients between solute components in these melts. The saturated solubility of carbon in Fe-C-V melt can be calculated with the following formula: XC=0.2043+0.8365XV or -lnXC-9.683XC=-11.96XV- 0.3916. The saturated solubility of carbon and nitrogen in Fe-C-V-N melt increases with increasing vanadium concentration. According to the thermodynamic properties of Fe-C melt, the activity interaction coefficients between carbon and nitrogen in Fe-C-N melt, the saturated solubility of carbon in Fe-C-V melt as well as the saturated solubility of carbon and nitrogen in Fe-C-N and Fe-C-V-N melts, by strictly thermodynamic derivation and calculation the activity interaction coefficients between carbon and nitrogen in Fe-C-N melt, between carbon and vanadium in Fe-C-V melt as well as between vanadium and nitrogen in Fe-C-V-N melt were obtained as follows: eCN=0.5016, eCV=-11.96, eCV=-0.2443 and eVN =-0.2379. Related Articles | Metrics

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Biosynthesis of Polyhydroxyalkanoates by Ralstonia eutropha with Short-chain-length Organic Acids YAN Qun; DU Guo-cheng; CHEN Jian    2003, 3 (5): 0-0.   Abstract （3836）      PDF （257KB）（1925）       Knowledge map    Save Separation of dimethyl carbonate (DMC) and methanol (MeOH) is very difficult due to the azeotrope of DMC and MeOH, the pressure swing method is an effective method for separation of DMC and MeOH azeotrope. In this paper, a joint process of high-pressure distillation and atmospheric distillation was investigated. Binary interaction parameters of the UNQUAC model between MeOH and DMC were regressed against experimental data of vapor liquid equilibria of MeOH and DMC, the applicable range of the model is: pressure 0.1~1.5 MPa, temperature 337~440 K. Based on the thermodynamic model, the separation flowsheet, inclnding a high-pressure distillation column and an atmospheric distillation column in series, was simulated and analyzed. Sensitivity of operation factors was discussed and the optimum operation parameters were proposed. The optimal parameters of the high-pressure distillation column were as follows: stage number 40, feed stage 29, reflux ratio 7~10, operation pressure 1.0~1.5 MPa. Related Articles | Metrics

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Suppressing the Impedance Rise of LiNi0.8Co0.2O2/Graphite Cells by Al, Ti and Mg Doping CHEN Chun-hua;XIE Song;LIU Jun;Amine K    2004, 4 (1): 59-63.   Abstract （3832）      PDF （140KB）（616）       Knowledge map    Save The research on utilizing lithium-ion batteries with LiNi0.8Co0.2O2-based cathode for hybrid electric vehicles is intensively underway in several national laboratories of US Department of Energy. The impedance of LiNi0.8Co0.2O2/graphite lithium-ion cells is observed to experience a substantial rise during accelerated calendar life storage, due mainly to the significant increase of the interfacial resistance on the cathode side. By means of electrochemical measurements and AC impedance spectroscopy, it is found that doping the LiNi0.8Co0.2O2 cathode with small amount of Al, Ti and Mg can effectively suppress this impedance rise. Possible mitigation of oxidizing ability of Ni4+ due to Al, Ti and Mg doping is proposed to achieve this impedance stabilization. Related Articles | Metrics

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Preparation and Tribological Investigation of PbS-TiO2 Nanocomposite Thin Films CHEN Yun-xia; WANG Bo; LIU Wei-min    2003, 3 (4): 0-0.   Abstract （3775）      PDF （200KB）（1188）       Knowledge map    Save In view of the existing problem of the former control system of the Yangzhi Petrochemicals butadiene distillation column, voluminous plant operation data collected by DCS and simulated results from a theoretical model are pooled together and used to build the adaptive soft-sensor instrument for butadiene and alkynes contents in the distillation column top based on the BP neural network technique. Then, an inferential control system was designed according to the targets of product quality, in which the on-line estimating values of soft sensor instrument were used. As a result of increasing logic calculation in the inferential control arithmetic, the robustness of the control system is strengthened. Application of the control system to the column showed that the control system can run smoothly over a long period in worksites, and has realized the close-loop control of product quality. Related Articles | Metrics

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Solid Circulating Rate in a Spouted–fluidized Bed with Draft Tube at Elevated Pressure LIU Xiang-dong; ZHANG Ming-yao    2001, 1 (1): 0-0.   Abstract （3719）      PDF （124KB）（1079）       Knowledge map    Save The effects of operating factors, such as spouting velocity, fluidizing velocity, pressure and particle size on solid circulating rate in a spouted–fluidized bed with draft tube were investigated. The experimental results showed that the spouting velocity was the most important factor. The solid circulating rate increased with increasing fluidizing velocity and pressure, and decreased with increasing mean particle diameter. Based on the experimental results, an empirical correlation of the solid circulating rate was established. This work is helpful to designing the carbide furnace in the second generation PFBC–CC system. Related Articles | Metrics

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Equilibrium Solubility in Ternary System of MeSO4-(NH4)2SO4-H2O at 298 K MU Si-guo;PENG Chang-hong;HUANG Hong;TANG Mo-tang    2006, 6 (1): 32-36.   Abstract （3659）      PDF （187KB）（625）       Knowledge map    Save The phase equilibrium in the ternary system of MeSO4-(NH4)2SO4-H2O at 298 K was studied by isothermal equilibrium method and many significant experimental results were obtained. In the ternary system of MnSO4-(NH4)2SO4-H2O, there were 3 saturation curves given by MnSO4×H2O, (NH4)2Mn(SO4)2×6H2O and (NH4)2SO4, respectively. There were 2 co-saturation points, A having the composition of MnSO4×H2O and (NH4)2Mn(SO4)2×6H2O, and B given by (NH4)2Mn(SO4)2×6H2O and (NH4)2SO4. There were 3 purification crystallization areas given by (NH4)2Mn(SO4)2×6H2O, MnSO4×H2O and (NH4)2SO4, respectively. In the ternary system of ZnSO4-(NH4)2SO4-H2O, there were 3 saturation curves given by (NH4)2Zn(SO4)2×6H2O, ZnSO4×7H2O and (NH4)2SO4, respectively. There were 2 co-saturation points, C having the composition of (NH4)2Zn(SO4)2×6H2O and ZnSO4×7H2O, and D given by (NH4)2SO4 and (NH4)2Zn(SO4)2×6H2O, respectively. There were 3 purification crystallization areas given by (NH4)2Zn(SO4)2·6H2O, ZnSO4×7H2O and (NH4)2SO4, respectively. In the ternary system of FeSO4-(NH4)2SO4-H2O, there were 3 saturation curves given by (NH4)2Fe(SO4)2·6H2O, FeSO4×7H2O and (NH4)2SO4, respectively. There were 2 co-saturation points, E having the composition of (NH4)2Fe(SO4)2×6H2O and FeSO4×7H2O, and F given by (NH4)2Fe(SO4)2×6H2O and (NH4)2SO4, respectively. There were 3 purification crystallization areas of FeSO4×7H2O, (NH4)2Fe(SO4)2×6H2O and (NH4)2SO4, respectively. These experimental results gained above not only give theoretical guidance for the double-salt precipitation deep purification of such solutions containing Fe2+, Mn2+ and Zn2+, etc., but also establish foundation for study on the quarternary system consisting of Fe2+, Mn2+, Zn2+ and NH4+/SO42--H2O. Related Articles | Metrics

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Bioleaching of Ni–Cu Sulfide with Acidophilic Thermophile Acidianus brierleyi ZHAO Yue-feng; FANG Zhao-heng    2001, 1 (2): 0-0.   Abstract （3611）      PDF （126KB）（790）       Knowledge map    Save Amino acids are very important nutrients in mammalian cell cultivation. Amino acids metabolism varies greatly from one cell line to another, and specific culture media were therefore designed to cover the needs of individual lines. The paper investigated the amino acid metabolism of Vero cells in batch culture by HPLC. The results showed that 12 amino acids (Gln, Arg, His, Leu, Thr, Ile, Lys, Ser, Tyr, Phe, Val and Met) were consumed, and 4 amino acids (Glu, Asp, Ala and Pro) were produced during the growth of Vero cells. 6 amino acids ( Leu, Thr, Ile, Lys, Phe and Tyr) were consumed quickly only in the exponential phase of growth and consumed very slowly in the stationary phase of growth. Related Articles | Metrics

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Portable X-ray Photography of Solid Concentration in Gas–Solids Fluidized Beds — (I) Principle and Image Processing ZHANG Zhi-pan; LIU Hui-e; LUO Guo-hua; WANG Zhan-wen; WEI Fei    2003, 3 (5): 0-0.   Abstract （3570）      PDF （119KB）（1167）       Knowledge map    Save The wetting ability of the solution of water-soluble cationic polymer NCP and the solution of HPAM (partial hydrolytic polyacrylamide) on the surface of Ca-montmorillonite was determined by a JF99A contact angle calcimetre. The former has a smaller contact angle than the latter. The results of relative wetting angle show that NCP has better hygroscopicity. On the other hand, when montmorillonite was saturately adsorbed by NCP and HPAM solutions and was disposed by filtrating, washing, drying and sieving, the results of contact angle in water solution show that the NCP–MT has better hygroscopicity than HPAM–MT. Related Articles | Metrics

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Production of Acrylic Acid via Catalytic Partial Oxidation of Propylene in a Two-stage Fluidized Bed FENG Qi-yao;LUO Guo-hua;WEI Fei    2008, 8 (1): 83-87.   Abstract （3557）      PDF （186KB）（1236）       Knowledge map    Save The experimental results on production of acrylic acid from catalytic partial oxidation of propylene using a single-stage fluidized bed (SSFB) reactor and a two-stage fluidized bed (TSFB) reactor were presented. Experimental investigation for the first-step reaction was conducted on variation of propylene conversion rate and liquid product yield with operating parameters, such as temperature, propylene space velocity, and ratio of oxygen to propylene. The results indicate that the propylene conversion rate and liquid yield in the first-step reaction can be greatly improved up to 94.2% and 74.4% respectively in a two-stage fluidized bed reactor due to effectively suppressing gas backmixing and growth of bubbles in the catalyst bed. Meantime, this work also presented the optimal conditions of space velocity of propylene 20~21 L/(h·kg), operating temperature 360~365℃ and molar ratio range of oxygen to propylene 1.6~1.8 in the first-step process. Moreover, the propylene conversion rate and liquid yields in the first-step and two-step process in the acrylic acid production were also examined under the optimal operating conditions. Related Articles | Metrics

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Distributions of Catalyst Concentration and Particles Velocity in a Large-scale Fast Fluidized Bed Reactor LI Guo-zhi DENG Hai-yan MA Yan-mei ZHANG Zhen-qian    2009, 9 (6): 1041-1047.   Abstract （3518）      PDF （326KB）（655）       Knowledge map    Save The flow characteristics of FCC particles were studied in a fast fluidized bed reactor with 300 mm diameter. Flow behaviors of gas and solids in the system were measured by pressure cyclic detecting and optical fiber measuring instruments, respectively. The effects of operating conditions on catalyst concentration, particles velocity, screening distribution along the bed axle and radial direction were examined. The experimental results show that when the superficial gas velocity is enhanced in 2.0~2.6 m/s, the catalyst flux is increased to 60~160 kg/(m2×s) and the axial distribution of catalyst concentration can be maintained in 50~650 kg/m3. The radial distribution of catalyst concentration is lower in the central region and higher near the wall. In the axial direction, the radial local catalyst concentration gradually decreases in the particle accelerating region and tends to smooth in the fully developed region. The radial local catalyst concentration decreases with superficial gas velocity increasing or catalyst flux decreasing, radial homogenization is improved. And catalyst concentration appears to be close at the non-dimensional radial position r/R<0.7. The radial distribution of particle velocity is the parabola structure with higher particle velocity in the central region and lower near the wall. The radial local particle velocity increases with superficial gas velocity increasing or catalyst flux decreasing. Related Articles | Metrics

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Research of 2D Substructure Search Program for Chemical Structure Database LIU Bing; ZHOU Jia-ju    2003, 3 (4): 0-0.   Abstract （3491）      PDF （143KB）（956）       Knowledge map    Save The structure and electrochemical properties of Zr0.9Ti0.1(Ni,Co,Mn,V)2.1 alloys prepared by both the melt-spinning method and the conventional induction melting were investigated. XRD studies showed that Zr0.9Ti0.1(Ni,Co,Mn,V)2.1 alloys at as-cast, melt-spinning and annealing were all the face center cubic structure with Laves C15 phase, and the higher the melt-spinning rate, the more the amorphous content. The electrochemical measurements showed that melt-spinning alloys had better activity, low discharge capacity (<270 mA×h/g); but after annealed, the alloys are activated completely with 30 cycles, the capacities about 340 mA×h/g were higher than those of the as-cast and melt-spinning alloys; the annealed alloys had better cycle stability than that of the as-cast alloy, and the higher the melt-spinning rate, the more stable the alloy became. Related Articles | Metrics

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Relationships between Pressure Fluctuation and Flow Patterns in Standpipes of Circulating Fluidized Bed ZHANG Yi;PENG Yuan-yuan;WEI Yao-dong;SHI Ming-xian    2008, 8 (1): 23-27.   Abstract （3460）      PDF （541KB）（751）       Knowledge map    Save Pressure fluctuation in the f90 mm and f42 mm standpipes in a 15 m circulating fluidized bed was measured. The gas-solid two-phase flows under negative pressure gradient in the standpipes have low frequency pressure fluctuation, which can be described by standard deviation (Sd). Flow patterns in standpipes are classified as two types according to solids flux, dense conveying pattern and dilute-dense coexisting flow pattern. The pressure fluctuation intensity is great under the dense conveying pattern, which is mainly caused by intensive mutual action between solid and the gas entrained down. The pressure fluctuation intensity is relative weak under the dilute-dense coexisting flow pattern, which is caused by instabilities of solid discharge at the bottom dense part and weak gas-solid mutual action in the upper dilute part. With the solid flux increasing in the standpipes, pressure fluctuation is more intensive. For the dense conveying pattern, there exists nearly linear relationship between solid flux and pressure fluctuation intensity as Sd=0.00875Gs'-4.77 under the experimental condition of Gs'=550~850 kg/(m2×s). Related Articles | Metrics

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Investigation of Surfactant–Stain–Metal Interaction: Naphthochrome Green/Cetyltrimethylammonium Bromide/Rare Earths Ternary Complexation ZHENG Li-xin;SHEN Rong;GAO Hong-wen    2003, 3 (5): 0-0.   Abstract （3415）      PDF （256KB）（959）       Knowledge map    Save The solubility of the three component system H3BO3–NaCl–MgCl2–H2O at 25 and 100oC has been measured. On the basis of the phase diagram constructed, the process technology of producing H3BO3 by hydrochloric acid decomposition from certain Ulexite in Tibet has been analyzed. Related Articles | Metrics

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Leaching of a Low-grade Refractory Tantalum–Niobium Ore by KOH Sub-molten Salt ZHOU Hong-ming; ZHENG Shi-li; ZHANG Yi    2003, 3 (5): 0-0.   Abstract （3408）      PDF （197KB）（1766）       Knowledge map    Save Production of lignin peroxidase (LiP) and manganese peroxidase (MnP) in three kinds of reactors (stirred tank reactor, bubble column reactor and aeration reactor) by Phanerochaete chrysosporium was studied. High activity of enzymes, especially for LiP, was obtained in the aeration reactor. The production of enzymes and decoloration of orange I were investigated in semi-continuous culture and continuous culture respectively. High activity of enzymes for a long period of time was detected in the semi-continuous culture, in which five batches of dye wastewater could be decolored to more than 90% and the specific decloration rate of orange I was above 46.7 g/(g×d) when the proportion of replacement was 1/2, while enzymes decayed rapidly and poor decoloration was gained in the continuous culture. The application of semi-continuous culture in the aeration reactor was tried for the decoloration of four batches of printing-wastewater, and the decelerations rate of the first three was all above 90%. Related Articles | Metrics

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Production of Citric Acid from Apple Pomace Enzymolyzed by Cellulase SONG Ji-rong;HUANG Jie;XU Kang-zhen;ZHAO Qiao-yun    2003, 3 (5): 0-0.   Abstract （3335）      PDF （120KB）（1513）       Knowledge map    Save Cellulase can evidently increase the content of glucose and has a significant effect on the production of citric acid from apple pomace by Aspergillus niger. Based on experiments, a cellulolytic enzyme named cellulase A6 was found able to produce about 170 g glucose from 1 kg dried apple pomace after 12 h reaction, with cellulase concentration of 20 U/g in the medium at 50oC, natural pH without pretreatment of alkali. Using the treated apple pomace as a liquid state substrate, Aspergillus niger-C selected out was able to produce about 256 g citric acid from 1 kg dried apple pomace at 35oC in 3 d or 30oC in 5 d with flask rotation speed of 210 r/min, and the conversion of citric acid could reach 80% based on the amount of sugar consumed. Related Articles | Metrics

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Effect of Al-containing Precursors on Ionothermal Synthesis of Aluminophosphate Molecular Sieve WANG Shao-jun;HOU Lei;XU Yun-peng;TIAN Zhi-jian;YU Jia-you;LIN Li-Wu    2008, 8 (1): 93-96.   Abstract （3314）      PDF （372KB）（681）       Knowledge map    Save Aluminophosphate molecular sieve AlPO4-11 was synthesized in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bromide as both the solvent and template with different Al sources at ambient pressure. The effects of composition of incipient gels, crystallization time and crystallization temperature on synthesis of AlPO4-11 molecular sieve with different Al sources were investigated. The structure of AlPO4-11 molecular sieve was characterized by X-ray diffraction and scanning electron microscopy. The results indicated that the different properties of raw materials lead to the different mechanisms and rules on the ionothermal synthesis. When Al[OCH(CH3)2]3 was used as the Al source, the optimal ratio of P/Al in the incipient gels was 3/1, the crystallization was slow. When Al2O(CH3COO)4·4H2O was used as the Al source, the ratio of P/Al in the incipient gels was low (P/Al=1.5/1) and the crystallization was rapid. Related Articles | Metrics

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Treatment of Coking Wastewater Using the Micro-electrolysis-SBR Activated Sludge Process ZHANG Wen-yi    2003, 3 (5): 0-0.   Abstract （3303）      PDF （286KB）（1751）       Knowledge map    Save Challenges and opportunities to antibiotics are reviewed. Antibiotics, which have greatly enhanced human health, now are facing the issue of drug resistance of pathogen microbes and newly found diseases. However, modern biotechnology, including genomics, proteomics, bioinformatics and bio-macromolecular crystallization, is providing new ideas and methodology for the research and development of new pharmaceuticals. Related Articles | Metrics

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Electrochemical Characteristics of Ti/SnO2+Sb2O3/PbO2 Anode for the Oxidation of Cr3+ in Sulfuric Acid Solution WANG Ya-qiong; CHEN Chang-ping; TONG Hong-yang; XU Wen-lin    2001, 1 (2): 0-0.   Abstract （3300）      PDF （366KB）（783）       Knowledge map    Save Based on the Stokes formula and Lambert–Beer Law, a series of recurrence formulae were advanced to calculate particle size distribution from the data obtained by disc centrifuge photosedimentation, with the effect of extinction efficiency of particles and the radial dilution during sedimentation considered. The experimental results show that the calculation process is simple and the result is accurate. This method can be also used for particle sedimentation in gravitational field. Related Articles | Metrics

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Preliminary Investigation on Interphase Mass Transfer in Agitated FANG Jing;YANG Chao;YU Geng-zhi;MAO Zai-sha    2005, 5 (2): 125-130.   Abstract （3285）      PDF （263KB）（1139）       Knowledge map    Save Volumetric mass transfer coefficients were determined for liquid-liquid-solid dispersion in a mechanically agitated baffled tank with internal diameter D=0.118 m. The effects of agitation speed (210～460 r/min), inert glass beads diameter (74～355 μm in size), type of impeller (Rushton, PTU, PTD), impeller-to-bottom distance (D/6, D/4, D/3), mass fraction of inert glass particles (<2%) on the mass transfer of typical liquid-liquid extraction system n-butanol-deionized water-succinic acid were examined. The data were collected on-line using a conductivity probe and processed with a PC computer. The mass transfer coefficients of liquid-liquid and liquid-liquid-solid systems were compared under the same operation conditions. It is revealed that the presence of a solid phase enhances the interphase mass transfer. The experimental results are discussed in light of hydrodynamics in stirred tanks. Related Articles | Metrics

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Self-assembly Mechanism and Defect Analysis of Colloidal Silica Photonic Crystals ZHAO Xiao-feng;ZHANG Hui;TANG Qing    2003, 3 (5): 0-0.   Abstract （3208）      PDF （167KB）（1753）       Knowledge map    Save Colloidal silica photonic crystals were prepared by using ethanol as medium. Nanospheres with a mean diameter of 238 nm and standard deviation 5.7% were obtained under strictly controlled conditions by using the improved Stober method. In this method, ethanol was proved a better medium than water and the prepared photonic crystals had fewer defects. The diffraction to incident infrared light obeyed the Bragg equation. The formation mechanism and defect formation of colloidal photonic crystals were also discussed. Related Articles | Metrics

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Purification of Phosphoric Acid by Solvent Extraction LUO Guang-sheng; LIU Shun-hua; SUN Yong; HUANG Hua-fei; DAI You-yuan    2001, 1 (2): 0-0.   Abstract （3200）      PDF （124KB）（1182）       Knowledge map    Save A study of purification of Chinese WPA by solvent extraction was carried out. The effect of temperature on distribution coefficient was investigated and the mechanism of extraction was discussed. The experimental results show that n-butanol has the highest capacity to extract phosphoric acid. With the increase of temperature, the distribution coefficient is found to decrease slightly. The study of extraction mechanism indicates that phosphoric acid is extracted in the form of neutral molecules. Accordingly, other stronger acids such as HCl added to the initial solution will be beneficial to the recovery of phosphoric acid. The fact that the metal ions in WPA are not extracted into the solvent makes out that the solvent extraction is one of the best methods to purify WPA. Related Articles | Metrics

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The State-of-the-art and Future Perspectives of World Petroleum Refining Technology LIU Hai-yan;YU Jian-ning;BAO Xiao-jun    2007, 7 (1): 176-185.   Abstract （3191）      PDF （280KB）（859）       Knowledge map    Save Entering into the 21st century, world petroleum refining technology is experiencing its great innovation driven by the increasing supply of heavy oils with decreasing quality and the fast increases in the demand for clean and ultra-clean vehicle fuels and petrochemical raw materials. In this review, the current situation of the world petroleum refining industry and technology is analysed and our outlook into the future technological innovations is presented. It is concluded that the main technological progress will be directed to heavy oil upgrading, cleaner transportation fuel production and the integration of refining and petrochemical businesses. For heavy oil upgrading, hydrocracking and hydrotreating technology will be the main directions, new residue FCC technology and new delayed coking should be developed further. For cleaner transportation fuel production, the main task is the desulfurization of gasoline and diesel. With the advents of various techniques, such as adsorption and biodesulfurization, the future development will be still centralized on hydro-desulfurization techniques. In the integration of refining and petrochemical businesses, new technologies based on traditional FCC process will be of increased interests to refiners because of their potential to meet the increasing demand for light olefins. Meanwhile, hydrocracking, due to its flexibility, will take the central position in the integration of refining and petrochemical businesses in 21st century. Related Articles | Metrics

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Application of Experimental Design to Optimizing the Medium of Nuclease P1 XU Zheng-jun; XIAO Lin-ping; LU Hao; XIE Ning-chang; YING Han-jie    2002, 2 (5): 0-0.   Abstract （3121）      PDF （160KB）（714）       Knowledge map    Save Hydrolysis characteristics of Ti(OC4H9)4 in the Ti(OC4H9)4-C2H5OH-H2O system were investigated for the preparation of TiO2 thin films via the sol-gel process. Experimental results are given about the effects of the system acidity (or basicity) and the addition of acetylacetone and AgNO3 on the viscosity and gelation time of the system. It was found that the introduction of AgNO3 can greatly improve the stability of the sols and prolong the gelation time besides adjusting pH and adding acetylacetone Related Articles | Metrics

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Phase Transition and Transition Temperature Hysteresis of VO2 Thin Film HU Zai-yong; XU Chu-shao; YANG Shao-li; CHEN Guang-bi    2002, 2 (5): 0-0.   Abstract （3120）      PDF （135KB）（808）       Knowledge map    Save The VO2 thin film was prepared by the colloid method with industrial V2O5 as raw material. The properties of the VO2 film such as resistance abrupt drop temperature, phase transotion temperature hysteresis are examined. The results show that the VO2 thin film phase transition temperature is 35oC. Preparation method and substrate show greater effect on resistance abrupt change order, which can reach 2~3 order if common glass or quartz glass were employed in underlay by H2 reduction process, while it can reach 1.5~2 order of magnitude by N2 thermal decomposition. The resistance abrupt change order of magnitude is larger for VO2 film with quartz glass as substrate, the transition temperature hysteresis is 1~6oC, and closely related with the resistance abrupt change order, underlay, substrate and preparation method. Related Articles | Metrics

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Properties of Ionic liquids and Its Applications in Catalytic Reactions WANG Jun-feng; ZHANG Suo-jiang; CHEN Hui-ping; LI Xian; ZHANG Mi-lin    2003, 3 (2): 0-0.   Abstract （3102）      PDF （255KB）（1059）       Knowledge map    Save The progresses in the study of ionic liquids (ILs) are critically reviewed, the structure–property relationships and the basic rules are summarized. The applications of ILs in some catalytic reactions are itemized, with special attention given to metal-catalytic and bio-catalytic reactions and reaction–separation coupling processes. High activity and selectivity of enzymes are found in trace water containing or non-aqueous ILs, which may bring the breakthrough in the synthesis and catalysis. Supercritical CO2/ILs and IL/water/organic phase provide new ways for reaction– separation coupling, which may have great effects on green chemistry. Related Articles | Metrics

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Preparation of Organic-Inorganic Multifunctional Nanocomposite Coatings CHEN Yun-fa; WANG Rui-ming; WU Zhen-jiang; XIE Yu-sheng    2003, 3 (4): 0-0.   Abstract （3100）      PDF （119KB）（1003）       Knowledge map    Save Oxidation of para-aminophenol in supercritical water was investigated at 480~550oC, 32~38 MPa with 100%~270% H2O2 in excess. Experiments were performed in a tubular continuous flow reactor with effective volume of 13 ml. Results indicate that para-aminophenol is easily oxidized in supercritical water. The COD elimination efficiency is significantly improved as reaction temperature, pressure or residence time is increased. 98.5% COD removal was obtained in 229 s at 550oC, 38 MPa with 190% H2O2 in excess. In this case, the global kinetics for COD was 2.13 order. The activation energy was 29.3 kJ/mol. Related Articles | Metrics

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Plasmid Stability in High Cell Density Cultures of E.coli HB101(pBR322) YU Guo-ce; JIAO Rui-shen; WANG Ji-cheng; WANG Shu-qing    2001, 1 (2): 0-0.   Abstract （3096）      PDF （142KB）（1041）       Knowledge map    Save Plasmid stability and the activity of b-lactamase were examined in the factorial fed-batch cultures of E.coli HB101(pBR322) in a fermentor. No loss of plasmid pBR322 was observed when temperature shifted from 33 oC to 39 oC, pH from 6.4 to 7.2, dissolved oxygen (DO) from 40% to 80%, the feed rate from 5.4 g/h to 10.8 g/h under the condition of density up to 27.3 g/L and the specific growth rate up to 0.73 h-1. The specific activity of b-lactamase, however, decreased in high cell density cultures. Related Articles | Metrics

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Computational Fluid Dynamic Simulation of Liquid-Liquid Mixing in a Static Double-T-shaped Micromixer E. A. MANSUR WANG Yun-dong DAI You-yuan    2008, 8 (6): 1080-1084.   Abstract （3088）      PDF （248KB）（867）       Knowledge map    Save The laminar flow structure and mixing performance of T-shaped and double-T-shaped micromixers with rectangular cross-section have been investigated using computational fluid dynamic (CFD) simulation. FLUENT software is used to evaluate the mixing efficiency. The numerical simulation results show that the presented double-T-micromixer is highly efficient over T-shaped micromixer. The performance of double-T-micromixer with and without static mixing elements (SME) is also investigated. The enhancement in mixing performance is thought to be caused by the generation of eddies and lateral velocity component when the mixture flows through these elements. Mixing efficiency as higher as 97% is reached within a mixing length of 320 mm downstream from the first T-junction with the enhancement of three SMEs. Related Articles | Metrics

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Effect of Different Types of Gas in Gas Stripping Ethanol Fermentation (GSEF) ZHANG Jun;LIU Hong-juan;LIU De-hua    2005, 5 (3): 349-352.   Abstract （3078）      PDF （207KB）（730）       Knowledge map    Save The effect of air, CO2, N2 and pure N2 as stripping gas on the cell physiology and ethanol production in GSEF was studied. The experimental results indicate that different stripping gases have different effects on the cell growth as well as ethanol and glycerol production in GSEF. Aeration stimulated cell growth and glycerol production, and maintained cell count and viability, but decreased ethanol productivity. CO2 appeared to be inhibitory to yeast growth and decreased overall glycerol production. 99.5%～99.8% N2 was verified to be the best type of gas in GSEF, for ethanol and glycerol productivity increased respectively by 2 and 1.9 times than that of the control (fed-batch fermentation without gas stripping). Furthermore, study on pure N2 (99.999%) employed in GSEF showed that the rate of cell growth decreased greatly after 47 h of the fermentation. However, the cell count, viability and ethanol productivity could recover original levels when changing the stripping gas from N2 to air, and the data obtained proved that the final ethanol productivity increased by 1.3 times than the control. Related Articles | Metrics

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Photocatalytic Degradation of Rhodamine B Using Semiconductors Photosensitized by Poly(fluorene-co-thiophene) under Visible Light Irradiation ZHANG Dong-dong;MO Yue-qi;SONG Lin;HUANG Xiong-fei;QIU Rong-liang    2008, 8 (1): 78-82.   Abstract （3074）      PDF （420KB）（714）       Knowledge map    Save The TiO2 and ZnO based photocatalysts prepared by poly(fluorene-co-thiophene) (PFT) modified TiO2 and ZnO have good photocatalytic activity under visible light. The results of Rhodamine B degradation showed that the photocatalytic activity of PFT/TiO2 was much better than that of PFT/ZnO. After 2 h irradiation under LED (light-emitting diode) lamp, Rhodamine B was completely degraded to colorless product, and the mineralization rate was 48% in PFT/TiO2 system. However, in PFT/ZnO system, there were lots of colored products left under the same condition, and the mineralization rate was only 24.6%. There were two steps involved in the degradation process of Rhodamine B. Firstly, the maximum absorbance peak became lower, and simultaneously there was a hypsochromic shift in the spectra. Secondly, Rhodamine B was decolored and degraded to produce Rhodamine. In the second step, Rhodamine was mineralized to CO2 and H2O continuously and the removal of TOC (total organic carbon) mainly took place in this step. Related Articles | Metrics

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Effects of He-Ne Laser Irradiation on the Mutagenesis of Beauveria bassiana YANG Ge; CHEN Hong-zhang; LI Zuo-hu    2003, 3 (5): 0-0.   Abstract （3064）      PDF （110KB）（1429）       Knowledge map    Save CaCO3 uniform nanoparticles with particle size of 10~30 nm were synthesized in quaternary W/O microemulsion solution containing Triton X-100, cyclohexane and n-pentanol. The reaction conditions were optimized on the basis of investigation of the influence of the ratio of water to surfactant, the concentration of reactants and the ageing time on the products. Transmission electron microscopy (TEM) was utilized to characterize the shape and size of the obtained nanoparticle products. Related Articles | Metrics