β-葡萄糖五乙酸酯的合成

以吡啶为催化剂,利用葡萄糖和乙酸酐的酯化反应合成了β-葡萄糖五乙酸酯,研究了合成的最佳反应条件和粗产品的结晶条件。结果表明最佳条件为：乙酸酐与葡萄糖的物质的量比为1:6,催化剂的用量为葡萄糖质量的20%,反应时间为3 h,结晶溶剂为乙醇,结晶温度为30 ℃,乙醇与粗产品的体积比为2:1;葡萄糖与醋酐的酯化收率达96%,β-葡萄糖五乙酸酯的总收率为75.2%。产品的比旋光度+4～+6°,熔点130～134 ℃,质量分数≥98%（GC）。该方法选择性好、产物收率高。     

气体添加剂对热脱硝过程影响的实验和建模研究

An experimental study of thermal DeNOx process with different additives was performed in an electricity- heated tubular flow reactor, showing that CO is less effective to lower the optimum temperature than H2 and CH4. The maximum NO reduction is lowered with H2 added, while it is hardly affected by CO or CH4. The temperature window is widened appreciably with CH4 added, while it is narrowed slightly by H2 or CO. The disadvantage of CH4 is that it causes CO emission due to its incomplete oxidation, and the maximum conversion of CH4 to CO is more than 50%. In general, the calculation using a detailed chemical kinetic model predicts most of the process features reasonably well. The analysis on reaction mechanism shows that the effects of these additives on NO reduction are achieved principally by promoting the production of &;#8226;OH radical.     

环形喷嘴预混无焰燃烧的数值模拟(英文)

This paper reports an investigation of Computational Fluid Dynamics (CFD) on the influence of injection momentum rate of premixed air and fuel on the flameless Moderate or Intense Low oxygen Dilution (MILD) combustion in a recuperative furnace. Details of the furnace flow velocity, temperature, O2, CO2 and NOx concentrations are provided. Results obtained suggest that the flue gas recirculation plays a vital role in establishing the premixed MILD combustion. It is also revealed that there is a critical mo-mentum rate of the fuel-air mixture below which MILD combustion does not occur. Moreover, the momentum rate appears to have less significant influence on conventional global combustion than on MILD combustion.     

涡-气泡作用模型对搅拌釜中气泡湍流扩散影响的数值研究

Based on trajectory equations of gas bubble, an eddy-bubble interaction (EBI) model was developed. This model considered the effect of non-drag forces and took the eddy-bubble interaction time as the refreshing time scale of turbulent fluctuations. The relationship between the crossing-eddy time and the eddy lifetime was discussed, and the predicted distributions of radial, axial ve-locities of bubbles and gas holdup were also given. Compared with eddy lifetime (EL) model, the EBI model gives somewhat smaller axial velocity in the upper circulation region and larger velocity in the lower circulation region, causing that fewer bubbles reach the lower circulation region and gas holdup becomes higher in the upper circulation region. The predicted gas holdup by the EBI model approaches closer to the experimental data in the discharge stream region.     

拟稳态模型用于间歇萃取精馏的数值模拟

Batch extractive distillation (BED) is a special method used in the distillation process by adding a solvent into the batch distillation column to alter the relative volatility of the components and improve the separation. A comprehensive design and simulation method is required due to the complexity of BED. In this study, a quasi-steady-state model for BED is proposed, the derivation and solution of the model are presented. This shortcut model can be used to simulate the composition and temperature of the reboiler, the top and other plates of the column in a batch extractive distillation operation. The calculated values are in good agreement with the experi-mental data. The results show that the quasi-steady-state model is a practical method because of some advantages such as high precision and fast calculation.     

利用简化的化学反应动力学模型耦合CFD代码模拟气体燃烧器中的烟黑生成(英文)

A computational study of soot formation in ethylene/air coflow jet diffusion flame at atmospheric pressure was conducted using a reduced mechanism and soot formation model. A 20-step mechanism was derived from the full mechanism using sensitivity analysis, reaction path analysis and quasi steady state (QSS) approximation. The model in premixed flame was validated and with computing savings in diffusion flame was applied by incorporating into a CFD code. Simulations were performed to explore the effect of coflow air on flame structure and soot formation. Thermal radiation was calculated by a discrete-ordinates method, and soot formation was predicted by a simple two-equation soot model. Model results are in good agreement with those from experiment data and detailed mechanism at atmospheric conditions. The soot nucleation, growth, and oxidation by OH are all enhanced by decrease in coflow air velocity. The peak soot volume fraction region appears in the lower annular region between the peak flame temperature and peak acetylene concentration locations, and the high soot oxidation rate due to the OH attack occurs in the middle annular region because of high temperature.     

拟塑性流体中伴有聚并的气泡上升混沌特征(英文)

The chaotic characteristics of bubbles rising with accompanying coalescences in pseudoplastic aqueous carboxymethylcellulose sodium (CMC) solution were studied by means of smoothed pseudo Wigner-Ville distribution and Wigner-Hough distribution. The temporal signal of bubble passage was measured utilizing a photoconductive data acquisition system. As bubble coalescence occurred, the smoothed pseudo Wigner-Ville distribution of the signal revealed that the signal could be divided into low-frequency and high-frequency ranges and the transition range according to the distribution feature of frequency domain, which reflected eddy motion of fluid, high frequency fluctuations of fluid velocity and other random components measured in the signal, and bubbles rising accompanied with coalescences, respectively. However, bubble coalescence occurred in the lower position and the frequency range of bubbles motion became wide under higher gas flowrate, while the frequency range of bubbles motion became narrow when the CMC concentration increased. The typical dynamics of bubbles motion, such as periodicity, bifurcation and chaos, could be easily found in terms of the Wigner-Hough distribution.     

翅片导流板填料应用于旋转填料床的特性

For an alcohol/water system and with fin baffle packing, continuous distillation experiments were carried out in a rotating packed bed (RPB) system at atmospheric pressure. The effects of the average high gravity factor (β), liquid reflux ratio (R) and feedstock flux (F) on the momentum transfer and mass transfer were investigated. The gas phase pressure drop of RPB increased with the average high gravity factor, liquid reflux ratio and feedstock flux, which was 13.55-64.37 Pa at β of 2.01-51.49, R of 1.0-2.5, and F of 8-24 L&;#8226;h－1 for a theoretical tray in the RPB with fin baffle packing. The investigation on the mass transfer in the RPB with different packings showed that the number of transfer units of RPB with a packing also increased with the average high gravity factor, reflux ratio and feedstock flux. It is found that the fin baffle packing (packing III) presents the best mass transfer performance and lowest pressure drop for the height equivalent to a theoretical plate (HETP), which is 6.59-9.84 mm.     

多孔介质中水合物生成与分解的电阻率性质

A new one-dimensional system for resistivity measurement for natural gas hydrate (NGH) exploitation is designed, which is used to study the formation and decomposition processes of NGH.The experimental results verify the feasibility of the measurement method, especially in monitoring the nucleation and growth of the NGH.Isovolumetric formation experiment of NGH is performed at 2 ℃ and 7.8 MPa.Before the NGH formation, the ini-tial resistivity is measured to be 4-7 Ω·m, which declines to the minimum value of 2-3 Ω·m when NGH begins to nucleate after the pressure is reduced to 3.3 MPa.As the NGH grows, the resistivity increases to a great extent, and finally it keeps at 11-13 Ω·m, indicating the completion of the formation process.The NGH decomposition ex-periment is then performed.When the outlet pressure decreases, NGH begins to decompose, accordingly, the resis-tivity declines gradually, and is at 5-9 Ω·m when the decomposition process ends, which is slightly higher than the resistivity value before the formation of NGH.The occurrence and distribution uniformity of NGH are determined by the distribution and magnitude of the resistivity measured on an one-dimensional sand-packed model.This study tackles the accurate estimation for the distribution of NGH in porous medium, and provides an experimental basis for further study on NGH exploitation in the future.     

雷丸的中性金属蛋白酶的分离纯化、酶学性质及体外驱虫活性

A neutral metalloprotease was purified from the cultured mycelia of Laccocephalum mylittae, an effective medicinal fungus widely used in anthelmintic therapy. The protease was purified to homogeneity with 31.85-fold purification and a final yield of 21.76%. The subunit molecular weight of the protease is about 40000 estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum reaction pH and temperature are 7.5 and 50ºC, respectively. The protease activity is largely enhanced by Ca2+, but highly inhibited by tetrasodium ethylenediaminetetraacetate (EDTA), a metal-chelator, suggesting that the enzyme is a metalloprotease. The Michaelis-Menten constan Km and Vmax value for casein substrate are 6.09 mg&;#8226;ml－1 and 21.32 μg&;#8226;min－1&;#8226;ml－1, respectively. In vitro anthelmintic tests of the protease exhibit distinct lethal effects on the third stage larvae (L3) of Ascaris suum. Scanning electron microscopy and SDS-PAGE analysis indicates that the proteolysis of larvae proteins caused by this protease may relate to the anthelmintic activity of L. mylittae.     

微囊藻毒素-RR的提取与生物降解

对采集的微囊藻毒素-RR(microcystin-RR,MC-RR)提取并在其含量达到0.1 mg/g(湿重)的基础上,采用鞘氨醇单胞菌降解菌株对提取的MC-RR的生物降解进行了研究。结果表明在温度为30℃、pH=7.0并且有氧条件下,反应体系中初始浓度为42.3 mg/L的MC-RR在36 h内被完全降解。利用高效液相色谱(HPLC)分析发现,在MC-RR生物降解过程中相继出现两个降解产物,其中第一个降解产物的紫外扫描图谱与MC-RR相似度高达95%。     

Biodegradation of phenol at high concentration by a novel bacterium: Gulosibacter sp. YZ4

BACKGROUND: A novel bacterial strain, Gulosibacter sp. YZ4, has been isolated from activated sludge. Its application potential for phenol biodegradation has not yet been reported, therefore, in this study, biodegradation tests using strain YZ4 were executed under different conditions. RESULTS: The strain was identified as a new member of the genus Gulosibacter and nominated as Gulosibacter sp. YZ4. Phenol biodegradation tests showed that strain YZ4 could thoroughly biodegrade 1000 mg L^?1 phenol across a wide temperature range from 10 to 42 °C and pH range 5 to 11. Degradation of 1000 mg L^?1 phenol was not inhibited by the coexistence of p‐cresol or quinoline. During phenol degradation, strain YZ4 excreted both phenol hydroxylase and catechol 1,2‐dioxygenase to efficiently metabolize phenol. At 36 °C, pH 7.5, strain YZ4 could effectively degrade phenol at concentrations as high as 2000 mg L^?1 within 76 h. Haldane's model with the parameters obtained from the experiments could successfully describe the behavior of the phenol biodegradation by the strain YZ4. CONCLUSIONS: The strain YZ4 has a high potential for applications in phenol wastewater treatment in view of its adaptability to temperature and pH fluctuations and great tolerance to other coexistent toxics. Copyright © 2011 Society of Chemical Industry     

新筛选菌种Delftia sp.XYJ5生物降解苯胺的途径

A promising gram-negative bacterial strain for the biodegradation of aniline as the sole carbon, nitrogen and energy sources was successfully isolated and identified as Delftia sp. XYJ6. The optimal temperature and pH for both the growth of Delftia sp. XYJ6 and the biodegradation of aniline were 30°C and 7.0, respectively. Initial aniline of 2000 mg•L－1 could be completely removed by the strain at 22 h, which showed that Delftia sp. XYJ6 had a strong ability in the biodegradation of aniline. It indicated that aniline was firstly converted to catechol catalyzed by aniline dioxygenase as a first product, which was then further biodegraded to cis,cis-muconic acid catalyzed by the catechol 1,2-dioxygenase of Delftia sp. XYJ6 as a second product. Cis,cis-muconic acid could also be further biodegraded to other small compound again. The pathway for the biodegradation of aniline by Delftia sp. XYJ6 was not previously reported.     

Enhancement of Phenol Biodegradation by Pseudochrobactrum sp. through Ultraviolet-Induced Mutation

The phenol-degrading efficiency of Pseudochrobactrum sp. was enhanced by ultraviolet (UV) irradiation. First, a bacterial strain, Pseudochrobactrum sp. XF1, was isolated from the activated sludge in a coking plant. It was subjected to mutation by UV radiation for 120 s and a mutant strain with higher phenol-degrading efficiency, Pseudochrobactrum sp. XF1-UV, was selected. The mutant strain XF1-UV was capable of degrading 1800 mg/L phenol completely within 48 h and had higher tolerance to hydrogen ion concentration and temperature variation than the wild type. Haldane’s kinetic model was used to fit the exponential growth data and the following kinetic parameters were obtained: μ_max = 0.092 h⁻¹, Ks = 22.517 mg/L, and Ki = 1126.725 mg/L for XF1, whereas μ_max = 0.110 h⁻¹, Ks = 23.934 mg/L, and Ki = 1579.134 mg/L for XF1-UV. Both XF1 and XF1-UV degraded phenol through the ortho-pathway; but the phenol hydroxylase activity of XF1-UV1 was higher than that of XF1, therefore, the mutant strain biodegraded phenol faster. Taken together, our results suggest that Pseudochrobactrum sp. XF1-UV could be a promising candidate for bioremediation of phenol-containing wastewaters.     

假单胞菌QLD-9的分离鉴定及其对喹啉的生物降解

[方法]采用富集培养法从受杂环类污染的土壤中分离喹啉降解菌株。[结果]分离得到1株以喹啉为唯一氮源、葡萄糖为碳源生长的QLD-9菌株,经16S rDNA鉴定为假单胞菌属(Pseudomonas sp.),该菌株能在48 h内将300 mg/L的喹啉降解99.9%以上,对600 mg/L以内喹啉具有良好的降解效果。[结论]QLD-9菌株对环境中喹啉的生物修复具有很好的应用潜力。     

Biodegradation of Di-n-Butyl Phthalate by a Newly Isolated Halotolerant Sphingobium sp.

A Gram-negative strain (TJ) capable of growing aerobically on mixed phthalate esters (PAEs) as the sole carbon and energy source was isolated from the Haihe estuary, Tianjin, China. It was identified as belonging to the Sphingobium genus on the basis of morphological and physiological characteristics and 16S rRNA and gyrb gene sequencing. The batch tests for biodegradation of di-n-butyl phthalate (DBP) by the Sphingobium sp. TJ showed that the optimum conditions were 30 °C, pH 7.0, and the absence of NaCl. Stain TJ could tolerate up to 4% NaCl in minimal salt medium supplemented with DBP, although the DBP degradation rates slowed as NaCl concentration increased. In addition, substrate tests showed that strain TJ could utilize shorter side-chained PAEs, such as dimethyl phthalate and diethyl phthalate, but could not metabolize long-chained PAEs, such as di-n-octyl phthalate, diisooctyl phthalate, and di-(2-ethyl-hexyl) phthalate. To our knowledge, this is the first report on the biodegradation characteristics of DBP by a member of the Sphingobium genus.     

Biodegradation ofVernonia galamensis seed Oil byAcinetobacter andPseudomonas sp.

The biodegradability ofVernonia galamensis seed oil (VO) has been demonstrated with two environmental bacterial strains,Acinetobacter Iwoffi (HU 3955), andPseudomonas sp. (HU 4020). A time-dependent increase in the degradative activities of both bacteria species was apparent. There wasca. 60% decrease in the amount of VO over an eightday incubation period. Additionally, lipolytic activity was evident from the amount of free fatty acid (FFA) that was generated. The percent FFA of the residual oil were 82% for thePseudomonas strain, and 62% for theAcinetobacter strain. The weight per epoxy value of the VO in the fermentation medium remained relatively constant over the incubation period, suggesting the lack of preference for either the epoxidized or nonepoxidized acids present in VO.     

肉桂皮提取残渣生物降解制备肉桂酰胺

筛选到能使肉桂皮提取残渣降解生成肉桂酰胺的菌株CG19,该菌株被鉴定为链霉菌(Streptomyces sp.)。进行了生物降解转化合成研究,用红外光谱仪、气相色谱-质谱联用仪、高效液相色谱仪对产物进行了表征。优化了生物降解条件,优化条件为:ρ(肉桂渣)=8.0 g/L,ρ(湿菌体)=40 g/L,反应体系的初始pH=5.0,30℃反应3 d,在该条件下肉桂酰胺的收率达0.32%。     

Simultaneous heterotrophic nitrification and aerobic denitrification at high initial phenol concentration by isolated bacterium Diaphorobacter sp. PD-7

A strain capable of phenol degradation, heterotrophic nitrification and aerobic denitrification was isolated from activated sludge of coking-plant wastewater ponds under aerobic condition. Based on its morphology, physiology, biochemical analysis and phylogenetic characteristics, the isolate was identified as Diaphorobacter sp. PD-7. Biodegradation tests of phenol showed that the maximum phenol degradation occurred at the late phase of exponential growth stages, with 1400 mg·L-1 phenol completely degraded within 85 h. Diaphorobacter sp. PD-7 accumulated a vast quantity of phenol hydroxylase in this physiological phase, ensuring that the cel s quickly utilize phenol as a sole carbon and energy source. The kinetic behavior of Diaphorobacter sp. PD-7 in batch cultures was investigated over a wide range of initial phenol concentrations (0–1400 mg·L-1) by using the Haldane model, which adequately describes the dynamic behavior of phenol biodegradation by strain Diaphorobacter sp. PD-7. At initial phenol concentration of 1400 mg·L-1, batch experiments (0.25 L flask) of nitrogen removal under aerobic condition gave almost entirely removal of 120.69 mg·L-1 ammonium nitrogen within 75 h, while nitrate nitrogen removal reached 91%within 65 h. Moreover, hydroxylamine oxidase, periplasmic nitrate reductase and nitrite reductase were successful y expressed in the isolate.     

Biodegradation of High Molecular Weight Polycyclic Aromatic Hydrocarbons Mixture by a Newly Isolated Fusarium sp. and Co-Metabolic Degradation with Starch

One native fungal strain, designated ZH-H2, was isolated from an agricultural soil contaminated by HMW-PAHs in a typical coal mining area of Hebei, China. The filamentous fungus was identified as a Fusarium sp. ZH-H2 was able to survive not only in the presence of the individual HMW-PAHs of Chry, BaA, B(K)F, BaP, DB(a,h)A, InP, InP and B(g,h,i)p but in the presence of a mixture of the above seven HMW-PAHs with a total concentration of up to 10 mg L^?1. Biodegradation experiments demonstrated that Fusarium sp. (ZH-H2) was able to degrade the aforementioned individual HMW-PAHs, with a degradation percentage of 77%, 85%, 91%, 42%, 56%, 42% and 38%, respectively, and degrade the aforementioned seven PAHs mixture with a degradation percentage of 48%. The effect of starch addition on the biodegradation efficiency of the PAH mixture was also investigated. The results showed a significant improvement in the degradation extent of the PAH mixture with the increase of starch concentration. The greatest degradation rate (DR; 89%) in 7 d was obtained when starch was added at 1.0 g L^?1, about 2-fold than was achieved without starch. This study implicates that Fusarium sp. (ZH-H2), a potential biodegrader, is suitable for practical field application in effective bioremediation of soils that have been simultaneously contaminated by several HMW-PAHs for a long time.