SO_3采样技术改进及烟气处理设备SO_3脱除能力测试

燃煤烟气中SO_3由于其特有的化学性质,一直是国内外燃煤电厂污染物测试的难点之一。参照国内应用广泛的SO_3控制冷凝法,自制了一套SO_3采样系统,在综合考虑烟气SO_3采样过程中的各种影响因素后,通过试验模拟,确定了SO_3控制冷凝法采样系统最佳蛇形管内径、圈径和圈数,以及采样管、过滤器和循环水浴的伴热温度控制,从而提高了SO_3的捕集效率。利用该SO_3采样系统对烟气进行采样,测试燃煤锅炉烟气处理设备对SO_3的脱除能力,分析其影响因素及捕集机理。结果显示:SCR脱硝催化剂对SO_2具有一定的催化作用,且随烟气温度的升高,SO_2/SO_3转化率升高;对于SO_3的脱除效率(各设备进出口浓度对比),干式除尘设备可达80%以上,湿法脱硫设备为35%~40%;湿式电除尘器为70%~75%。

不同烟温下低低温电除尘器粉尘脱除能力的比较分析

粉尘比电阻、粉尘粒径对电除尘器的除尘效率有重要影响。低低温电除尘器通过降低进入电除尘器的烟气温度,进而降低粉尘比电阻和电场风速,提高除尘效率。基于华能某300MW燃煤机组的低低温电除尘器,在130、93、84℃三种不同烟温下通过现场对粉尘比电阻、粉尘粒径进行测试比较分析,结果揭示,运行温度由130℃降低84℃时,比电阻降幅达到73.7%,粉尘的脱除效率提升到99%以上,为指导低低温电除尘器的选型,提高其适用性提供理论基础和实验支撑。

一种新的调节分栅闪存存储器擦除能力的方法

基于分栅闪存存储器的擦除能力是评估其单元性能的关键参数,阐述现有制程调节分栅闪存存储器擦除能力的方法。提供一种新的方法通过控制侧壁氧化物的剩余厚度来调节分栅快闪存储器擦除能力,并讨论其优势所在。

高性能层状二硅酸钠的合成研究

层状二硅酸钠因具有优良的助洗、绿色环保特性,被认为是最具发展前景的洗涤助剂,但商业化层状二硅酸钠的钙镁离子交换能力不高。为此,探索了添加助剂(KCl)制备高钙镁离子交换能力层状二硅酸钠的工艺规律,并用X射线衍射仪(XRD)、红外(FT-IR)等手段对产物进行表征。研究结果表明:加入KCl[n(K)∶n(Si)=0.015],在680℃煅烧0.5 h得到了高钙镁交换能力(分别为360 mg/g和430 mg/g)的层状二硅酸钠。

De-eutrophication of effluent wastewater from fish aquaculture by using marine green alga Ulva pertusa

The de-eutrophication abilities and characteristics of Ulva pertusa, a marine green alga, were investigated in Qingdao Yihai Hatchery Center from spring to summer in 2005 by analyzing the dynamic changes in NH4-, NO3-, NO2- as well as the total dissolved inorganic nitrogen （DIN）. The results show that the effluent wastewater produced by fish aquaculture had typical eutrophication levels with an average of 34.3 ~mol L-1 DIN. This level far exceeded the level IV quality of the national seawater standard and could easily lead to phytoplankton blooms in nature if discarded with no treatment. The de-eutrophication abilities of U. pertusa varied greatly and depended mainly on the original eutrophic level the U. pertusa material was derived from. U. pertusa used to living in low DIN conditions had poor DIN removal abilities, while materials cultured in DIN-enriched seawater showed strong de-eutrophication abilities. In other words, the de-eutrophication ability of U. pertusa was evidently induced by high DIN levels. The de-eutrophication capacity of U. pertusa seemed to also be light dependent, because it was weaker in darkness than under illumination. However, no further improvement in the de-eutrophication capacity of U. pertusa was observed once the light intensity exceeded 300 pmolM2 S1. Results of semi-continuous wastewater replacement experiments showed that U. pertusa permanently absorbed nutrients from eutrophicated wastewater at a mean rate of 299 mg/kg fresh weight per day （126 mg/kg DIN during the night, 173 mg/kg in daytime）. Based on the above results, engineered de-eutrophication of wastewater by using a U. pertusa filter system seems feasible. The algal quantity required to purify all the eutrophicated outflow wastewater from the Qingdao Yihai Hatchery Center into oligotrophic level I dean seawater was also estimated using the daily discharged wastewater, the average DIN concentration released and the de-eutrophication capacity of U. pertusa.

Isolation and Characterization of Fucoidans from Five Brown Algae and Evaluation of Their Antioxidant Activity

In this study, we evaluated the chemical property and antioxidant activity of fucoidans isolated from brown algae, Laminaria japonica(LJF), Lessonia nigrescens(LNF), Lessonia trabeculata(LTF), Ascophyllum mackaii(AMF), and Ecklonia maxima(EMF). LJF was less in sulfate content(14.16%) and more in galactose and mannose content(1.08 and 0.68) than the documented early. EMF contained 20%–30% of sulfate and fucose, 0.97 in molar ratio which was lower than that of sulfate to other four fucoidans(1.21–1.41). AMF(162 kDa) and EMF(150 kDa) were the first two largest in molecular weight, which were followed by LJP(126 kDa), LNF(113 kDa) and LTF(105 kDa). The fucoidans isolated these algae showed a wide range of antioxidant activity in vitro. It was found that the reducing power of the isolated fucoidans was positively correlated with their sulfate content and molecular weight. In addition, LNF and LTF at low concentrations exhibited high superoxide and hydroxyl radical scavenging activity. This demonstrated that low molecular weight fucoidans may perform a high antioxidant activity.

Purification and characterization of novel antioxidant peptides of different molecular weights from mackerel Pneumatophorus japonicus protein hydrolysate

Mackerel （Pneumatophorus japonicus） proteins were hydrolyzed by five proteases： trypsin, papain, neutrase, acid protease, and flavourzyme. The hydrolysate treated by neutrase exhibited the highest antioxidant activity. Response surface methodology （RSM） was employed to optimize the hydrolysis conditions in an effort to obtain a mackerel protein hydrolysate （MPH） with the highest DPPH radical scavenging activity. The MPH was fractioned using a series of ultrafiltration membranes and five fractions, namely, MPH-I （〉10 kDa）, MPH-II （10-2.5 kDa）, MPH-III （1-2.5 kDa）, MPH-IV （0.4-1 kDa）, and MPH-V （below 0.4 kDa）, were obtained. DPPH radical scavenging activity, reducing power, hydroxyl radical scavenging activity, and the lipid peroxidation inhibition capability of these fractions were evaluated. The fractions in molecular weights 〈2.5 kDa （MPH-III, MPH-IV, and MPH-V）, which occupied 93.4% of the total fractions, showed the strongest antioxidant activity; and the antioxidant activities of the three fractions are similar to each other. Using SP Sephadex C-25 and Sephadex G-25 columns, eight fractions were obtained from the MPH （〈2.5 kDa）. The isolated peptide I （1 664 kDa） displayed the highest DPPH radical scavenging activity. Therefore, MPH is a potential source of antioxidant peptides.

The Antioxidant Effects of Complexes of Tilapia Fish Skin Collagen and Different Marine Oligosaccharides

An excess of reactive oxygen species（ROS）leads to a variety of chronic health problems.As potent antioxidants,marine bioactive extracts containing oligosaccharides and peptides have been extensively studied.Recently,there is a growing interest in protein-polysaccharide complexes because of their potential uses in pharmaceutical and food industries.However,only few studies are available on the antioxidant activities of such complexes,in terms of their ROS scavenging capability.In this study,we combined and superoxide radicals,and to evaluate the influences on the activities of superoxide dismutase（SOD）,glutathione peroxidase（GSH-Px）and the level of malondialdehyde（MDA）in UV-induced photoaging models.The results indicated that the antioxidant activities of all the complexes were stronger than those of their individual components.Among the 11 complexes tested,two complexes,namely MA1000＋CP and κ-ca3000＋CP,turned out to be highly effective antioxidants.Although the detailed mechanisms of this improved scavenging ability are not fully understood,this work provides insights into the design of highly efficient peptide-oligosaccharide complexes for potential applications in pharmaceutical,cosmetics and food industries.

Evaluation of Hydroxyl Radical and Alkyl-oxy Radical Scavenging Activity of Coffee by ESR Spin Trapping Method

We evaluated the hydroxyl and alkyl-oxy radical scavenging activity of instant coffee using an electron spin resonance （ESR） spin-trapping method, which was based the spin-trapping reagent 5-（2,2-dimethy-l,3-propoxycyclophosphoryl）-5-methyl-l-pyrroline N-oxide （CYPMPO）. In this method, very pure hydroxyl and alkyl-oxy radicals were generated by illuminating a phosphate buffer solution containing hydrogen peroxide and 2,2＇-azobis （2-amidinopropane） dihydrochloride with a Hg-Xe arc lamp. The ESR adduct signal was sensitive and very stable. We concluded that instant coffee has high hydroxyl radical and alkyl-oxy radical scavenging activity.

Removal of Uranium（Ⅵ） by Fixed Bed Ion-exchange Column Using Natural Zeolite Coated with Manganese Oxide

The adsorption of uranium(Ⅵ)on the manganese oxide coated zeolite(MOCZ)from aqueous solution was investigated in a fixed-bed column.The experiments were conducted to investigate the effects of bed height,flow rate,particle size,initial concentration of uranium(Ⅵ),initial pH,presence of salt and competitive ions.The U-uptake by MOCZ increased with initial uranium(Ⅵ)concentration and bed height,but decreased as the flow rate and particle size increased.In the presence of salt and competitive ions,the breakthrough time was shorter.The adsorption capacity reached a maximum at pH of 6.3.The Thomas model was applied to the experimental data to determine the characteristic parameters of the column for process design using linear regression.The breakthrough curves calculated from the model were in good agreement with the experimental data.The BDST model was used to study the influence of bed height on the adsorption of uranium(Ⅵ).Desorption of uranium(Ⅵ)in the MOCZ column was investigated.The column could be used for at least four adsorption-desorption cycles using 0.1mol.L-1 NaHCO3 solution as the elution.After desorption and regeneration with deionized water,MOCZ could be reused to adsorb uranium(Ⅵ)at a comparable capacity.Compared to raw zeolite,MOCZ showed better capacity for uranium(Ⅵ)removal.

Preoperative predictors of short-term survival after hepatectomy for multinodular hepatocellular carcinoma

AIM： To investigate preoperative factors associated with poor shore-term outcome after resection for multi- nodular hepatocellular carcinoma （HCC） and to assess the contraindication of patients for surgery, METHODS： We retrospectively analyzed 162 multi- nodular HCC patients with Child-Pugh A liver function who underwent surgical resection. The prognostic significance of preoperative factors was investigated by univariate analysis using the log-rank test and by multivariate analysis using the Cox proportional hazards model. Each independent risk factor was then assigned points to construct a scoring model to evaluate the in- dication for surgical intervention. A receiver operating characteristics （ROC） curve was constructed to assess the predictive ability of this system.RESULTS： The median overall survival was 38.3 mo （range： 3-80 too）, while the median disease-free sur- vival was 18.6 mo （range： 1-79 too）. The 1-year mor- tality was 14%. Independent prognostic risk factors of 1-year death included prealburnin 〈 170 rng/L [hazard ratio （HR）： 5.531, P 〈 0.001], alkaline phosphatase 〉 129 U/L （HR： 3.252, P = 0.005）, α fetoprotein 〉 20 μg/L （HR： 7.477, P = 0.011）, total tumor size 〉 8 cm （HR： 10.543; P 〈 0.001）, platelet count 〈 100×109/L （HR： 9.937, P 〈 0.001）, and y-glutamyl transpeptidase 〉 64 U/L （HR： 3.791, P 〈 0.001）. The scoring model had a strong ability to predict 1-year survival （area under ROC： 0.925, P 〈 0.001）. Patients with a score ≥5 had significantly poorer short-term outcome than those with a score 〈 5 （1-year mortality： 62% vs 5%, P 〈 0.001; 1-year recurrence rate： 86% vs 33%, P 〈 0.001）. Patients with score ≥5 had greater possibility of microvascular invasion （P 〈 0.001）, poor tumor dif- ferentiation （P = 0.003）, liver cirrhosis with small nod- ules （P 〈 0.001）, and intraoperative blood transfusion （P = 0.010）. CONCLUSION： A composite preoperative scoring model can be used as an indication of prognosis of HCC patients after surgical resection. Resection should be considered with caution in patients with a score ≥5, which indicates a contraindication for surgery.

Effects of calcium addition on as-cast microstructure and mechanical properties of Mg-5Zn-5Sn alloy

The effects of Ca addition on the as-cast microstructure and mechanical properties of the Mg-5Zn-5Sn (mass fraction,%) alloy were investigated.The results indicate that an addition of 0.5%-1.5% (mass fraction) Ca to the Mg-5Zn-5Sn alloy not only refines the as-cast microstructure of the alloy but also causes the formation of the primary and/or eutectic CaMgSn phases with high thermal stability;an increase in Ca amount from 0.5% to 1.5% (mass fraction) increases the amount and size of the CaMgSn phase.In addition,Ca addition to the Mg-5Zn-5Sn alloy improves not only the tensile properties at room temperature and 150 ℃ but also the creep properties.Among the Ca-containing Mg-5Zn-5Sn alloys,the one added 0.5% (mass fraction) Ca obtains the optimum ultimate tensile strength and elongation at room temperature and 150 ℃,however,the alloy added 1.5% (mass fraction) Ca exhibits the optimum yield strength and creep properties.

Oxidation Stability of Camellia Oil During Refining

In this paper, the crude camellia oil extracted by cold pressing and deacidified oil, decolorized oil, dewaxed oil and finished tea oil obtained in different refining stages were studied. The changes of acid value, peroxide value and free radical scavenging ability of camellia oil in each stage were compared and analyzed.The results showed that the total phenol content of crude oil was the highest, and the total phenol content of alkali refined crude oil decreased significantly. After dewaxing, the total phenol concentration of camellia oil increased by 63.5%. The reason may be that low temperature conditions contributed to the recovery of phenolic structure in camellia oil, and without the influence of alkaline solution, the damage degree of phenolic substances was greatly reduced, thus elevating the total phenol content. The lowest peroxide value of camellia oil was observed in the alkali-refining deacidification stage, which decreased by 29.3%. Crude oil had the highest acid value and concentration of antioxidant substances. After alkali-refining deacidification,the acid value and the concentration of antioxidant substances dropped by 85.3%and 88.9%, respectively. Total phenols had the strongest correlation with acid value,followed by free radical scavenging ability, and the correlation with peroxide value was not obvious.

Production and Purification of Antioxidant Peptides from Flatfish Skin Protein Hydrolysates

Antioxidant peptides of flatfish skin protein hydrolyzed by four enzymes （Papain, Pepsin, Trypsin and Neutrase, respectively）were investigated. The Trypsin hydrotysate obtained by hydrolysis exhibited the highest 1,1- dipheny-l-2-picrylhydrazyl（DPPH） radical scavenging activity （DRSA） compared with other hydrolysates. Re- sponse surface method ology （RSM）, based on Box-Behnken design, was used to study the influence of hydrolysis conditions on the DRSA. The optimal hydrolysis conditions were as follows： pH 7.38, temperature 48.2~C and en- zyme/substrate （E/S）ratio 2 840 U/g. Under these conditions, the maximum DRSA was （22.85 ＋ 0.57）%. The experimental values agreed with the value （23.09%） predicted by the model within a 95% confidence interval. By using gel filtration chromatography and reversed-phase high performance liquid chromatography （RP-HPLC）, anti- oxidant peptide （D2-P）was isolated from flatfish skin protein hydrolysates （FSPH）and could exhibit a （54.28 ± 1.37） % scavenging activity on DPPH radical at the concentration of 5 mg/mL. This is the first report of a scientific basis for the preparation of antioxidant peptides from flatfish skin. The results suggested that the antioxidant pep- tides can be exploited into functional foods or used as a novel source of nutraceuticals.

Studies on bio-oxidation of coal mine gas by a biofilter

A new biofilter technology was used to control the methane concentration in the coal mine. The results indicate that the biofilter achieves a steady methane removal capacity of 1 470 mg/（Loh） after 30 days start-up. More than 90% of the methane can be removed with an empty bed retention time （EBRT） of 5.6 min when the inlet concentration of methane （IMC） is lower than 70 mg/L （10%, V/V） and about 80% when IMC is at 105 mg/L （15%, V/V）. The biofilter is still a reliable method to control methane concentration as an auxiliary means to boost coal mine production safety together with aggrandized ventilation and drainage technologies, even though the removal efficiency of methane is not very satisfactory with a high IMC （〉10%） or a short EBRT （〈3.8 min）.

Design and choice of TFO binding and cleaving HBV core promoter

Objective: To screen a triple helix-forming oligodeoxyribonucleotide (TFO) that can bind HBV core promoter at target site with high affinity and specificity, and to observe the ability of manganese porphyrin modified TFO to combine and cleave HBV DNA. Methods: Similar homopurine domain (1 734 - 1 754) in HBV core promoter was selected as target sequence. Several corresponding TFOs were synthesized. The affinities and specificities of TFOs binding target sequence were tested with electrophoretic mobility shift and DNase I footprinting assays. The selected best TFO was modified with manganese porphyrin and acridine. The ability of the TFO derivative to cleave HBV DNA was observed with cleavage experiment. Results: Under the condition of 371 and pH 7. 4, the TFO consisting of cytidylate and thymidylate (CT-TFO) and the parallel TFO consisting of guanylate and thymidylate (GT-TFOp) bound the target sequence weakly with Kd values much more than 10 -6 mol/L. The affinities of anti-parallel GT-TFO ( GT-TFOap) and short TFO consisting of adenine nucleotide and guanylate (AG-TFOsh) binding the target sequence were higher than those of the formers, with Kd values of 5 μ 10-7 mol/L and 2. 5 μ 10-8 mol/L respectively. Long AG-TFO (AG-TF01) had the highest binding affinity with a Kd value of 3 μ 10 -9 mol/L among all the TFOs studied for sequence specificity. In the presence of potassium monopersulfate, KHSO5, TFO modified with manganese porphyrin and acridine cleaved the target sequence where the triplex DNA formed. Conclusion: TFO containing AG or GT binds homopurine in HBV core promoter in adverse parallel direction to form triple helix. AG-TFO1 has the highest binding affinity among all the TFOs studied. After modified with manganese porphyrin, AG-TFO1 completely binds and cleaves the target HBV DNA sequence where triplex DNA is formed.

Chemical and Biological Assessments of the Essential Oils of Chrysophyllum albidum G, Don

The chemical compositions of the essential oils obtained from six tree parts of Chrysophyllum albidum （Sapotaceae） were extracted by hydrodistillation and analyzed by gas chromatography （GC） and gas chromatography-mass spectrometry （GC-MS）. A total of 65, 33, 45, 21, 25 and 18 compounds, representing 79.49%, 100%, 90.81%, 98.43%, 96.62% and 98.37% of the total oil, were identified in the fruit bark, root bark, stem bark, seed bark, leaf and seed, respectively. The dominant compounds in the essential oils in six tree parts were m-xylene （66.7%; seed）, p-xylene （21.4%; seed bark）, a-farnesene （38.1%; leaf）, hexadecanoic acid （14.7%; stem bark）, m-xylene （53.1%; root bark） and hexadecanoic acid （12.7%; fruit bark）. The essential oils were evaluated for their antibacterial, antioxidant and insecticidal activities using Alamar blue assay, DPPH radical scavenging activity and contact toxicity test, respectively. The oils displayed moderate antibacterial potentials to some tested organisms and low radical scavenging activity to DPPH. Rhyzopertha dominica was susceptible to C. albidum stem bark essential oil only.

Study on the Molecular Weight Composition and Antioxidant Activity of Peanut Bioactive Peptides

[ Objective] To prepare peanut bioactive peptides and analyze their molecular weight composition and antioxidant activity. [ Method ] The dialysis bag of 8.0, 3.5 and 1.0 kD were used to classify the hydrolyzate derived from alcalase and flavourzyme, peanut bioactive poptides of differ-ent molecular weight were obtained and then their scavenging capacity of free radicals was measured. The molecular weight composition was stud-ied by Tricine-SDS-PAGE.[Result] The content of peptides 〈 1.0 kD were 76.21% and 83.42% in the total hydrolyzate from alcalase and fla-vourzyme respectively. All hydrolyzate with different molecular grades showed free radical scavenging capacity, which was increased with the reduc- tion of molecular mass. The peptides 〈 1.0 kD exhibited higher radical scavenging capacity of （87.41 ±0.66） % （alcalase） and （67.88 ±0.48）% （ flavourzyme）, respectively. [ Conclusion] Peanut bioactive peptides had strong effect of antioxidant capacity, especially that 〈 1.0 kD, which had great prospect.

HPLC-UV Analysis and Antioxidant Potential of Phenolic Compounds from Endemic Shrub of Arid Environment Tamarix pauciovulata J, Gay

This research presents complete phenolic compounds and biological activity of Tamarix pauciovulata J. Gay, an endemic Saharan species. The antioxidant assays revealed that crude extract showed strong DPPH scavenging activity （IC50 = 49.357 μg/mL） but in reducing power and hydrogen peroxide scavenging activity, butanolic and ethyl acetate fractions have a potent ferrous ion-chelating ability in particularly the butanolic fraction （63.18% reduced power at 50 μg/mL） and a powerful scavenging activity on hydrogen peroxide in particularly ethyl acetate fraction （IC50 = 0.205 μg/mL）. The phenolic compounds of Tamarix pauciovulata leaves were analyzed by HPLC-UV. The major phenolic of leaf extracts are syringic acid （1.07 g/100g）, quercetin （34.1 mg/100g）, kaempferol （5.77 mg/100g）, isorhamnetin （5 mg/100g）. Others phenols were identified such as isoquercetin, catechin, epicatechin and its derivatives. Results indicated that the leaves extracts from Tamarix pauciovulata have great capacities to prevent diseases caused by the overproduction of radicals and can become important source of dietary compounds with health protective potential.