半干旱区谷农采用化控间苗技术影响因素实证研究*

本文运用Logistic模型对半干旱区谷农是否采用化控间苗技术的影响因素进行实证分析。结果表明：谷子化控间苗技术较好的解决了谷子人工间苗难题,谷农的受教育程度、谷子种植面积比重以及技术认知效果对谷农是否采用化控间苗技术有显著的影响。依据研究结论,提出了加强农民科技文化和技术培训,加大半干旱区土地流转力度和培育谷子新型经营主体,加强谷子轻简高效生产技术集成等几点建议。     

磁性Fe3O4微粒表面有机改性及表征

利用化学共沉淀法制备了磁性Fe3O4纳米微粒,用硅烷偶联剂MPS对所制备的磁性微粒进行表面有机改性,并用FTIR、XRD、TEM、XPS等表征方法对样品进行了表征,结果表明:MPS已经很好地键连到了磁性Fe3O4纳米微粒的表面。改性的磁性Fe3O4纳米微粒具有亲水和亲油两种性质,采用改性后的磁性微粒可以显著改善磁性微球的性能指标。     

Guided and Team-Based Learning for Chemical Information Literacy

This case study recounts a process of course design, conduct, and evaluation for a single-session chemical information literacy class using guided and team-based learning. This approach incorporates active learning, worked examples, process worksheets, and POGIL elements. The instruction followed an iterative cycle of learning exercises whereby (1) the instructor introduces an information problem or task through a short presentation, (2) student teams collaboratively work through process worksheets that guide them through the technical and analytical tasks of resolving the information problem or task, (3) the instructor serves as a facilitator to address learning needs that arise during the exercise, while student teams analyze and reflect upon the learning activity and concepts, and afterwards, (4) the class engages in a discussion as an opportunity for evaluation, further exploration, and peer instruction. Overall, the guided and team-based learning approach offers opportunities to observe student progress closely and forges a collaborative spirit between students and the instructor for an engaging and rewarding experience.     

Ten Years of Change: National Library of Medicine TOXMAP Gets a New Look

The United States National Library of Medicine (NLM) TOXNET® databases <http://toxnet.nlm.nih.gov> provide broad coverage of environmental health information covering a wide variety of topics, including access to the U.S. Environment Protection Agency (EPA)'s Toxics Release Inventory (TRI) data. The NLM web-based geographic information system (GIS), TOXMAP® <http://toxmap.nlm.nih.gov/>, provides interactive maps which show where TRI chemicals are released into the environment and links to TOXNET for information about these chemicals. TOXMAP also displays locations of Superfund sites on the EPA National Priority List, as well as information about the chemical contaminants at these sites. This column focuses on a new version of TOXMAP which brings it up to date with current web GIS technologies and user expectations.     

Crystal growth of calcite at conditions of gas processing in solvent mixtures of monoethylene glycol and water

Growth kinetics of the most stable polymorph of calcium carbonate,calcite,has been studied in seeded stirred batch experiments in MEG-water solutions at 40 ℃ and 70 ℃,conditions relevant for the processing of natural gas.It was found that MEG changes the growth order from two in pure water to one in solvent mixtures of MEG and water.Assuming parabolic growth (growth order is equal to two),it could be shown that MEG decreases the growth rate constant for calcite from 0.52 nm/s to 0.11 nm/s (70 ℃) when the MEG-content is increased from 0 wt% MEG to 65 wt% MEG.Decreasing the temperature from 70 ℃ to 40 ℃ has a similar effect on the growth rate constant as raising the level of MEG to 65 wt%.     

Chemical kinetic modeling for the effects of methyl ester moiety in biodiesel on PAHs and NO x formation

In order to investigate the effects of methyl ester moiety on polycyclic aromatic hydrocarbons (PAHs) and NO x formation in biodiesel combustion, the combined models were developed based on detailed methyl butanoate (MB) oxidation model and n-butane model. Also, PAHs detailed reaction mechanism and NO x formation mechanism were added to the detailed models to form the combined models. The combined models were used to compare the combustion of n-butane and MB in a shock tube simulation to understand the effects of methyl ester moiety. The results indicated that compared with n-butane, the methyl ester moiety in MB leads to different reaction pathways, more CO and CO 2 formation and less formation of PAHs precursors such as ethylene and acetylene. In addition, a better chemical insight into the effects of methyl ester moiety on NO x formation was given, which will help to understand the combustion process of biodiesel.     

纳米TiO_2对X-3B溶液的降解动力学研究

以纳米TiO2为催化剂,紫外灯为光源,对X-3B溶液的光催化降解动力学进行了研究。降解反应动力学拟合结果表明,降解动力学规律符合Langmuir-Hinshelwood一级反应动力学模型。     

利用水泥窑协同处理化工污泥

利用水泥窑无害化处理各种工业、生活、医用垃圾是当前各国垃圾处理发展的新方向。皖维公司在化工生产过程中的废水经处理后产生大量污泥,为了减少其对环境的污染,加强对废物的利用,我公司水泥分厂开展了利用水泥窑处理污泥的研究工作,将压滤脱水后的污泥作为一种原料,与其他原料一起配料,生产中以每台水泥窑5~6t/h的使用量来处理污泥。工程实践结果证明,对生产工艺稍做调整后,在生料配料中掺入一定量的污泥,仍能保持生产稳定,熟料质量良好。     

CoMo/Al_2O_3-TiO_2催化剂上加氢脱除苯并噻吩宏观动力学研究

根据双曲线型动力学方程,以全局通用算法结合马夸特算法对动力学参数进行估值,建立了与实验数据相吻合的含硫模型化合物的加氢脱硫反应动力学模型,苯并噻吩的活化能为5.219 9×104J/mol。残差检验和统计学考察表明,模型计算结果和实验数据吻合良好。     

对比式教学法在化工原理教学中的应用

本文介绍了对比式教学方法的概念、作用、及在化工原理教学过程中的应用和实施过程应注意的问题。结果发现该方法能够激活学生的学习热情,提高学生的观察能力、分析问题及解决问题的能力。