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1.
阻燃剂硼酸锌的合成   总被引:4,自引:0,他引:4  
硼酸锌是一种性能优良的无机添加型阻燃剂。组成为 2ZnO·3B2 O3·3.5H2 O的低水合硼酸锌应用得最为广泛。采用硼砂法合成了低水合硼酸锌 ,用正交法确定的最佳工艺条件是 :反应温度为 338K ,硫酸锌和硼砂的配料比为 1 .0 5∶1 ,液固比为 3.5∶1 ,反应时间为6h .  相似文献   

2.
采用共沉淀法制备Fe2O3-SiO2混合氧化物前驱体,并对其进行水热改性处理,经浸渍(NH4)2S3O8溶液后再焙烧得S2O2-8/Fe2O3-SiO2固体酸催化剂.研究了制备条件对催化活性的影响,用乙酸/丁醇酯化反应评估该固体酸的催化性能.实验结果显示,最佳工艺条件为,n(Fe)∶n(Si)=1∶4,150℃水压热处理1h,在0.5 mol·L-1的(NH4)2S2O8溶液中浸渍6 h,500℃焙烧3 h,在此条件下乙酸的转化率可达94.11%.  相似文献   

3.
柠檬酸三丁酯的新合成法   总被引:4,自引:0,他引:4  
SO2 -4 /Zr O2 、Fe Cl3· 6H2 O、NH4 Fe(SO4 ) 2 · 1 2 H2 O三种催化剂对柠檬酸与正丁醇酯化反应的催化性能 ,结果表明 ,Fe Cl3· 6H2 O催化活性最高。通过系统地研究Fe Cl3· 6H2 O催化合成柠檬酸三丁酯的工艺条件 ,确定其适合的工艺流程为 :酸醇比 1∶1 2 .5,催化剂用量为 3% ,反应温度为 1 2 5℃ ,反应时间为 3h,这样酯化率可达 95%以上。  相似文献   

4.
Fenton试剂处理二硝基重氮酚工业废水的研究   总被引:6,自引:0,他引:6  
二硝基重氮酚(简称DDNP)是一种性能优良的起爆药,但生产过程中产生大量的工业废水,一般工艺处理困难。Fenton法(Fe2+和H2O2组成的氧化体系)是对难降解有机物处理过程的一种高级氧化工艺。研究了Fenton试剂处理DDNP废水的工艺条件。实验结果表明:投加[PAC]=3g·L-1,[FeSO4]=0.5~0.8g·L-1,[30%H2O2]=5ml·L-1,pH=3.5;石灰为1g·L-1;在常温下可以使废水的CODcr去除90%以上,色度小于100。处理后的废水至少可以回用于冲洗设备、工具、地面等,以节约水资源。  相似文献   

5.
采用P2O5溶剂缓释催化法合成长链烷基磷酸酯.考察了溶剂对P2O6的分散效果;催化剂对酯化率的影响;酯化时间,酯化温度,物料配比,催化剂用量对酯化反应的影响.磷酸酯的总酯化率可达85%以上,并且单双酯比例接近于1.溶剂缓释催化法合成高碳醇磷酸酯的最佳工艺条件为:酯化时间3.5 h,酯化温度70℃,物料配比2.5∶1,催化剂用量0.4 g,水解温度70℃,水解时间1.5 h.  相似文献   

6.
聚合硫酸铝生产工艺的研究   总被引:4,自引:0,他引:4  
研究了以纯碱副产品石灰和铝质易拉罐废料为原料生产聚合硫酸铝的工艺过程.考察了原料配比、温度、时间、pH值、稳定剂等因素对聚合硫酸铝盐基度和混凝效果的影响,得最适宜的工艺条件:Ca(OH)2与Al2(SO4)3物质的量比=1.5∶1,反应温度84℃,反应时间60~65min,pH3.5,稳定剂为柠檬酸.聚合硫酸铝溶液盐基度可达65%左右,用其处理高浊度工业废水浊度去除率大于97%,COD去除率大于92%,明显优于市售Al2(SO4)3·18H2O的处理效果.  相似文献   

7.
化学沉淀法脱除焦化废水中的氨氮   总被引:10,自引:0,他引:10  
研究了pH值、温度、化学试剂Na2HPO4·12H2O和MgCl2·6H2O的加入量等对焦化废水中氨氮脱除效果的影响。实验结果表明,当焦化废水中添加的Na2HPO4·12H2O和MgCl2·6H2O使NH4+∶Mg2+∶PO3-4的比率为1∶1∶1时,在pH=8~10的条件下,无论是均合池的生化进水还是混沉池的生化外排水,都可以将其氨氮含量脱除至10mg/L以下。  相似文献   

8.
以无机盐SnCl4 ·5H2 O ,SbCl5,NiCl2 ·6H2 O为原料 ,采用溶胶 凝胶工艺制备了Sb2 O3 和NiO掺杂的SnO2 薄膜 .研究了SnO2 ∶Sb∶Ni薄膜的电学和气敏性能 .实验研究表明 ,由于锑的掺杂 ,所制得的SnO2 ∶Sb∶Ni薄膜电阻较低 ,室温下其电阻只有 1 2 0kΩ/□ .而NiO作为催化剂 ,使其对NOx 气体具有较高的灵敏度和良好的选择性 .与SnO2 ∶Sb薄膜相比 ,其工作温度大大降低 ,在常温下对NOx 气体 (主要成分是NO)也具有一定的灵敏度 ;并且水汽不影响其对NOx 气体的灵敏度 .SnO2 ∶Sb∶Ni薄膜工作温度的降低主要是薄膜表面缺陷和颈连粒子的存在所致 .  相似文献   

9.
低铁硫酸铝生产新工艺研究   总被引:5,自引:0,他引:5  
介绍了利用铝灰生产硫酸铝 ,采用共沉法除铁新工艺。确定了最适宜工艺条件 :硫酸质量分数 30 % ,m( H2 SO4 ) ∶m( K2 Mn O4 )∶m A=1∶ 0 .0 0 78∶ 0 .0 0 2 6 ,p H值为 3,收率达93.2 %  相似文献   

10.
本文采用均匀沉淀法合成了纳米Bi2O3粉体材料,应用TEM、XRD、XPS对其形貌和结构进行了表征。通过实验研究确定纳米Bi2O3粉体最佳工艺条件:Bi^3+溶液的浓度为0.125mol·L^-1;DBS作为添加剂,其最佳浓度为0.023mol·L^-1;最佳焙烧温度750℃。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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