Determination of Optimum Conditions for X-Ray Fluorescence Analysis Using Coupling Equations

Coupling equations used to calculate the chemical composition of substances by X-ray fluorescence analysis can be classified as empirical, theoretical or semi-empirical based on the method for determining the coefficients of the calibration function. The advantages and disadvantages of each class of equations are discussed. Recommendations for the selecting the optimum conditions for determining empirical correction coefficients and their control during analysis are provided.

Direct Synthesis of Diphenyl Carbonate with Heterogeneous Catalyst and Optimal Synthesis Conditions of the Support Prepared by Sol-gel Method

The support of catalyst for the direct synthesis of diphenyl carbonate （DPC） by heterogeneous catalytic reaction was prepared by the sol-gel method. Compared with activated charcoal, molecular sieve, porous ceramics, hopcalite, the support prepared by the sol-gel method has higher activity. The characterization of the support by X-ray diffraction （XRD） and transmission electron microscope （TEM） show that the mare crystal phase is Co2MnO4 and the average particle diameter is about 40 nm. The optimum conditions for synthesis of the support were determined by orthogonal experiments, which indicate that the proportion of Cu, Mn, and Co is the first important factor influencing the yield and selectivity of DPC. Temperature of calcination is the second one. The optimum conditions are： molar proportion of Cu, Mn, and Co being 1 ： 1 ： 1, temperature of calcination 700℃, drying at 100~C, temperature of water bath 85~C. The yield and selectivity of DPC in the process can reach 38% and 99% in the batch operation, respectively. The copper cobalt manganese mixed oxides chosen as the support contribute more to the high catalytic activity than the sol-gel method.

Study on the Optimum Moisture Amount Added to Brown Rice once during the Wet Conditioning

In the experiment, the brown rice whose moisture content was 12.5% was used as raw material. The brown rice was grouped, then moisturized differently and milled. While milling, the energy consumption, the rate of broken rice and the crack rate were tested. It is confirmed that the stress crack owing to the moisture added to the brown rice can be avoided when the moisture amount added once is limited to no more than 1.5%. It is also proved that the energy consumption can be reduced, the yielding rate of rice can be increased and that the quality of rice can be improved.

Study on Direct Synthesis of Diphenyl Carbonate with Heterogeneous Catalytic Reaction (V) Screening Catalysts and Optimizing Synthesis Conditions

Pd/LaxPbyMnOz, Pd/C, Pd/molecular sieve and Pd-heteropoly acid catalysts for direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction were compared and the results of DPC synthesis indicated that the catalyst Pd/LaxPbyMnOz had higher activity. The Pd/LaxPbyMnOz catalyst and the support was characterized by XRD, SEM and TEM, the main phase was Lao.szPbo.asMnOa and the average diameter could be about 25.4nm. The optimuna conditions for synthesis of DPC with Pd/LasPbyMnOz were determined by orthogonal experiments and the experimental results showed that reaction temperature was the first factor of effect on the selectivity and yield of DPC, and the concentration of O2 in gas phase also had significant effect on selectivity of DPC. The optimum reaction conditions were catalyst/phenol mass ratio l to 50, pressure 4.5MPa, volume concentration of O2 25%, reaction temperature 60℃ and reaction time 4 h. The maximum yield and average selectivity could reach 13% and 97% respectively in the batch operation.

Herbicidal activity of Aureobasidium pullulans PA-2 on weeds and optimization of its solid-state fermentation conditions

Fungal strain PA-2 was isolated from infected poplar leaves from the Ping’an District, Haidong City of Qinghai Province, China. Based on the culture characteristics and the internal transcribed spacer(ITS) sequence of its 16S r DNA, the strain was identified as Aureobasidium pullulans. The culture and metabolites of strain PA-2 showed high herbicidal potential to five tested weeds Galium aparine var. tenerum, Chenopodium album, Malva crispa, Polygonum lapathifolium and Avena fatua. For the in vitro test, 5 days after the detached leaves were inoculated with PA-2 culture, all leaves infected by the hyphae and became black and rotten. For the in vivo test, a metabolite filtrate of PA-2 culture was sprayed over the living weed plants, and five days after inoculation, the weed plants became withered and necrotic. Seven days after inoculation, the fresh weight reductions of G. aparine var. tenerum, C. album, M. crispa, P. lapathifolium and A. fatua were 87.25, 78.46, 82.25, 62.11, and 80.27%, respectively. Galium aparine var. tenerum and M. crispa exhibited significant reductions in fresh weight. The bio-safety test on the five crops showed no significant plant height reductions, which was also observed for wheat(Triticum aestivum), faba bean(Vicia faba), and barley(Hordeum vulgare). By contrast, oilseed rape(Brassica napus) and pea(Pisum sativum) exhibited light spots but no significant reductions in plant height. These results indicated that A. pullulans could be a potential microbial herbicide for the control of the target weeds in crops. Optimization of the carbon and nitrogen sources for cultural media and substances for solid-state fermentation indicated that PA-2 had better colony growth and spore production with the optimal carbon source of glucose(C4), nitrogen source of soybean flour(N2), and the optimal substance was wheat bran. The results in this study provide useful information for the development ofA. pulluans PA-2 as an herbicide for bio-control of the weed.

An Experimental Study on Optimization of Large-volume Airgun Source Excitation Conditions in a Reservoir

Through manual pickup of seismic phases,the number of recording stations,the farthest observation distance of station and received energy are determined,then optimal operating condition processing software is developed to evaluate the excitation effect of operating conditions. The optimal operating conditions in the Mianhuatan Reservoir are determined using this software. They are: optimal water depth 25 m,airgun array sink depth 9m and airgun array size 7m × 7m. At the same time,accumulative stacking results for every 10 times are analyzed for 300 fixed-point excitations. It is concluded that the excitation effect shows a rapidly rising trend at 10 to 90 times stacking,a slowly rising trend at 100 to 150 times stacking,a rapidly rising trend at 160 to 240 times stacking,and a slowly rising trend at 250 to 300 times stacking. As the number of stacking increases,the propagation distance and the number of recording stations also increase gradually.

Optimum of Mobile Phase Condition for Resolving Isoflavones in RP-HPLC

In reversed-phase high performance liquid chromatography （RP-HPLC）, the mobile phase condition for separating eight isoflavones （daidzin, glycitin, genistin, 6＇-o-acetyl daidzin, 6＇-o-malonyl genistin, daidzein, glycitein and genistein） was optimized using the HCI （High-Purity Separation Laboratory, Department of Chemical Engineering, Inha University） program software. The optimum composition of mobile phase for the separation of the eight isoflavones was obtained. The elution profiles were calculated by the plate theory based on the equations of retention factor, In k=A＋BF＋CF2, where F was the volume percentage of acetonitrile with 0.1% acetic acid （AA）. The first mobile phase composition was water with 0.1% AA/acetonitrile with 0.1% AA （88%/12%, by volume）, followed at 9min later by the second composition of mobile phase which was step-changed to 85%/15%, at 19rain by the third composition which was step-changed to 73%/27%, at 30min when it was changed to 65%/35% and finally it was maintained in isocratic mode to the end of the run time at 50rain. Although, using step gradient mode to separate the isoflavones, the calculated and experimented data were not achieved very good agreement, we could estimate the closed retention time before experiment. And the agreement between the experimental data and the calculated values was relatively good using isocratic separation for eight isoflavones, but the retention time is very long.

Optimum condition by mechanical characteristic evaluation in friction stir welding for 5083-O Al alloy

The mechanical characteristies for friction stir welding (FSW) of 5083-O Al alloy were evaluated. The results show that in FSW at 800 r/min and 124 mm/min, a weld defect is observed at the start point. However, the button shape at the end point is good and the stir zone has a soft appearance. At 267 mm/min, a void occurs at the button. A slight weld defect and rough stir zone are seen both at the start and end points at 342 mm/min. Moreover, at the bottom, a tunnel-type void is observed from an early stage to the end point, and at 1 800 r/min, a weld defect can be found from an early stage to the end point. These defects are rough with imperfect joining due to excessive rotation speed and high physical force. Weld fractures relative to rotational and travel speeds are observed at the stir zone. The optimum FSW conditions are a welding speed of 124 mm/min and a rotational speed of 800 r/min.

响应面优化超声提取绿色棉纤维总黄酮

【目的】优化超声提取绿色棉纤维中总黄酮工艺条件,为合理利用及鉴别天然绿色棉纤维提供依据。【方法】以天然绿色棉纤维为原料,利用超声空化效应加速黄酮溶解于乙醇中,在单因素试验基础上,结合Box-Benhnken中心组合原理及响应面设计优化试验条件。【结果】料液比为1∶50 g/mL时,总黄酮得率达到最大值,提取最适料液比为1∶50 g/mL,响应面试验中建立的模型的CV值=0.87%,影响绿色棉纤维总黄酮得率的顺序为提取时间>乙醇浓度>料液比,A料液比为1∶50 g/mL、B乙醇浓度50%、C提取时间50 min为最佳提取条件。【结论】超声波法提取绿色棉纤维总黄酮的最佳条件参数为料液比1∶50 g/mL、乙醇浓度50%、提取时间50 min;获得平均总黄酮得率为5.25%。

微生物降解孔雀石绿研究进展

环境微生物是自然界中主要的分解者,在孔雀石绿降解中发挥着重要作用。由于缺乏低成本的替代品,孔雀石绿持续不断地释放到环境中,其环境分布和对人体健康的潜在影响已得到广泛的关注。综述了可降解孔雀石绿的细菌和真菌及其最适降解条件、降解途径、降解酶,总结了目前通过固定化和组学研究降解孔雀石绿的进展,进而对孔雀石绿的微生物降解领域未来研究趋势进行展望。以期为进一步开展微生物降解孔雀石绿机理研究与技术应用提供有价值的科学论据。

过硫酸钾与盐酸制取氯气的最佳条件探索

针对目前实验室用MnO_(2)与浓HCl反应制取氯气实验存在反应物用量没有说明,反应原理学生不易理解,现象不明显等缺陷,提出了实验室用K_(2)S_(2)O_(8)与HCl反应制备氯气,并利用正交试验法探讨了实验室用K_(2)S_(2)O_(8)与HCl反应制取氯气的最佳工艺条件。实验表明:用K_(2)S_(2)O_(8)与HCl反应制取氯气,避免了MnO_(2)与浓HCl共热制取氯气实验中的缺陷,且实验现象明显,反应速率适中,完全满足了课堂演示和学生实验的要求。因此,建议中学化学教学中选用该方法为制备氯气的课堂演示实验或学生实验。

四尾栅藻处理白酒酿造废水底锅水的研究

以四尾栅藻(Scenedesmus quadricauda)为材料、酿酒废水底锅水为培养基,探究栅藻对底锅水总磷、总氮、COD的去除情况,并对栅藻的成分进行分析。结果表明,在底锅水pH为6.0、质量分数为5%、四尾栅藻接种量为10%、光照强度为8 000 Lux时,培养6 d后COD降解率达到96.21%,总氮降低率为71.6%,总磷降低率为94.11%,培养液中藻生物量、油脂、碳水化合物含量均高于BG11标准培养基。该研究可为酿酒废水处理和微藻养殖的耦联提供实验基础。

1株白三叶根际产铁载体菌的功能特性及培养条件

为充分利用贵州岩溶山区牧草根际促生菌资源,以野生白三叶(Trifolium repens)根际铁载体产生菌TSQA26-3为研究对象,结合形态观察、VITEK-2全自动微生物鉴定系统和16S rRNA基因序列分析对菌株进行分类鉴定,开展菌株促生特性研究,筛选适宜菌株合成铁载体的发酵基础培养基,通过单因素试验和正交试验相结合,确定最佳培养基成分和培养条件,促进菌株合成铁载体能力的提升。结果表明,菌株TSQA26-3为恶臭假单胞菌(Pseudomonas putida);菌株同时还具有溶解无机磷、产植物生长素(IAA)和固氮能力;优化后的培养基(MG培养基)配方为,甘露醇25.0 g·L^(−1),L-谷氨酰胺2.5 g·L^(−1),K2HPO41.0 g·L^(−1),MgSO4·7H2O 0.25 g·L^(−1);最佳培养条件为,培养基初始pH 7.0,摇床转速170 r·min^(−1),培养温度30℃,培养基装液量为每250 mL瓶中装70 mL。

提高硝酸胍得率的工艺研究

本文对目前硝酸胍较为成熟的三条合成路线进行比对优选。优选了双氰胺合成法工艺,并对影响硝酸胍得率的因素进行探讨,寻找出有利于提高得率的较好反应条件及配比等。实验表明,硝酸胍得率的优选反应条件为:原料配比双氰胺与硝酸铵之间为1:2.1~2.2,以分段升温法进行反应,第一步反应温度为100~105℃,反应时间为30~40min,第二步反应温度为200~210℃,反应时间为60~70min,采用开始反应就连续通入氨气工艺,硝酸胍最终的得率可以达到92%以上,是一条具有较高硝酸胍得率的工艺路线。

臭氧催化氧化技术在焦化废水处理升级改造中的应用实践

为提高焦化废水处理出水水质,山西安泰集团股份有限公司采用臭氧催化氧化技术对原A2O废水处理工艺进行了升级改造。分析了臭氧催化氧化处理焦化废水的机理;介绍了升级改造的工艺流程;通过工艺调试考察了臭氧投加量、氧化时间及pH值对废水中COD的降解效果,确定最优工艺条件为:氧化时间45 min,臭氧投加量70 mg/L~90 mg/L,pH值7~9;在最优工艺条件下,焦化废水出水COD长期稳定在80 mg/L以下,COD降解率在40%左右。

除氟剂HJ-DF-07用于煤化工含氟废水深度处理实验研究

采用自主研发的除氟药剂HJ-DF-07对煤化工含氟废水进行了深度除氟实验研究。比对了市场常见的几种除氟药剂和HJ-DF-07的除氟效果;考察了废水pH值、反应时间、两级除氟工艺中HJ-DF-07各自投加量等因素对除氟剂HJ-DF-07氟去除率的影响。结果表明:除氟剂HJ-DF-07对氟离子的去除率比其他几种除氟剂高出约20个百分点,其最佳操作条件为:pH值10.37,反应时间10 min,两级除氟工艺除氟剂投加量分别为3.0 mL/L和2.0 mL/L,相应的一级、二级氟去除率分别为81.74%和92.82%,最终二级除氟装置出水氟离子质量浓度可降至0.976 mg/L,总氟去除率可达98.69%。

微通道反应器合成DBT连续工艺研究

传统的对苯二甲酸二丁酯(DBT)制备工艺需要使用催化剂,工艺相对繁琐且经济成本略高。本研究开发利用微通道反应器,以对苯二甲酸(PTA)和正丁醇为原料,在高温高压条件下不使用催化剂直接制备出对苯二甲酸二丁酯。通过考察反应温度、反应压力、停留时间、醇酸比等反应条件,最终确定最佳酯化产物收率工艺条件。最佳工艺条件在反应温度350℃左右、反应压力15 MPa、反应停留时间13 min、醇酸比20∶1时原料PTA一次酯化转化率达到99.13%,目标产物DBT收率达到82.83%;二次酯化原料转化率达到99.40%,目标产物收率达到90.12%。

脱氮除磷条件下MBR运行的最佳水力条件优化

以脱氮除磷及膜阻力为考察指标,研究曝气强度、搅拌转速、HRT对MBR运行的影响,利用正交试验优化MBR工艺运行条件.结果表明:由极差法和方差法分析可知,对MBR脱氮除磷影响的因素由大到小顺序依次是:HRT>搅拌转速>曝气强度,其中HRT对脱氮除磷去除效果的影响显著;对MBR膜阻力影响的因素由大到小顺序依次是:搅拌转速>曝气强度>HRT,其中搅拌转速对膜阻力的影响显著.由正交试验得出的MBR脱氮除磷最佳运行条件是:HRT为10 h,搅拌转速为120 r/min,曝气强度为120 L/h;延缓MBR膜污染最佳运行条件是:搅拌转速为120 r/min,曝气强度为120 L/h,HRT为8 h.综合MBR脱氮除磷效果及膜阻力指标、基建费用及运行成本考虑,确定MBR最佳运行水力条件:HRT为8 h,曝气强度为120 L/h,搅拌转速为120 r/min.

贵金属光催化剂处理混合含硫废气性能研究

以纳米级别的Pt/TiO_(2)光催化剂为原料,通过响应曲面法探究其催化含硫废气的最佳工况点。首先,通过三个单因素实验发现,废气风量、催化剂用量和紫外灯波长比例对含硫废气的平均净化效率均有一定的影响,但并非单一的线性关系。基于此,本研究采用响应曲面法耦合出最佳工况点:废气风量(A)=1 000 m^(3)/h,催化剂用量(B)=2.56,紫外光波长比例(C)=25.26%,最佳工况点下预测的平均净化效率为96.912%。最后,在响应曲面法的最优工况下展开对预测的含硫气体平均净化效率进行验证,最佳工况下纳米级别的Pt/TiO_(2)光催化剂对四种有机含硫废气的平均净化效率为96.522%,与响应曲面法平均净化效率的预测值(96.912%)误差仅为0.390%,表明响应曲面法对最佳工况下含硫废气平均净化效率的预测是值得信赖的,这也为后续其他催化剂最佳工况的耦合提供了理论支持。

基于正交试验设计的改性污泥基生物炭制备研究

为了进一步提高污泥基生物炭的吸附能力,采用掺入特定比例硫酸的氯化锌作为活化剂开展污泥基生物炭制备研究,通过正交试验结果可见,不同制备条件对生物炭碘吸附值影响的比较为:碳化温度>活化剂硫酸掺入比>碳化时间>活化剂浓度;结合不同制备条件对产率影响,获得最佳制备条件组合为:碳化温度500℃、活化剂硫酸掺入比60%、碳化时间1 h、活化剂浓度3 mol/L。在该组合条件下制备的改性污泥基生物炭碘吸附值为516.68 mg/g,产率为70.25%。