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1.
为研究脱胶对大麻纤维吸声性能的影响,选用正交设计法对大麻打成麻进行碱煮脱胶工艺优化,分析了脱胶时间、浴比、NaOH用量、Na2SO3浓度和Na2SiO3浓度对大麻纤维降噪系数的影响.结果表明,NaOHlOg/L,Na2SO3质量分数50%,Na2SiO3质量分数40%,浴比1:60,在100℃条件下处理5h,大麻纤维的吸声性能最好.  相似文献   

2.
碱金属氧化物对镍渣微晶玻璃性能的影响   总被引:2,自引:0,他引:2  
以镍渣及粉煤灰为主要原料制备R2O-MgO-Al2O3-SiO2系微晶玻璃,通过加入不同种类及质量分数的碱金属氧化物,探讨碱金属氧化物对微晶玻璃理化性能的影响.结果表明:利用镍渣制备的微晶玻璃致密且性能良好;加入Li2O、Na2O使得微晶玻璃物理性能随碱金属氧化物质量分数的增大而提高,当Na2O质量分数为10%、Li2O质量分数为2%时,其抗折强度可达138.34 MPa.微晶玻璃耐酸性与耐碱性则随碱金属氧化物质量分数的增大而降低.  相似文献   

3.
为提高综合利用率,对大洋多金属结核碱浸进行预处理研究,考察大洋多金属结核高压低质量分数碱浸过程中Na OH初始质量分数、反应温度、液固比、浸出时间等因素对SiO_2溶出影响,并对高压碱浸脱硅动力学进行研究。研究结果表明:在浸出温度为180℃、质量分数为10%Na OH溶液、液固比为3.0:1.0条件下反应70 min,可制得118.51 g/L的Na2Si O3溶液,其余Na2Si O3以方沸石(Na(Si2Al)O6?H2O)形式析出,SiO_2高压浸出反应的表观活化能为50.08 k J/mol,遵循化学反应控制的收缩核模型。通过高压低质量分数碱浸可选择性浸出其中的SiO_2,并生成有良好吸附性能的方沸石,而不破坏有用金属元素晶格结构,所得浸渣锰质量分数为30.72%以上。  相似文献   

4.
R2O-MO-Al2O3-SiO2玻璃的组成与其热膨胀系数的关系   总被引:11,自引:0,他引:11  
采用传统熔体冷却方法制得R2O-MO-Al2O3-SiO2多元系统玻璃(R为碱金属元素,M为碱土金属元素),玻璃组成(质量分数)为:SiO2,55.0%~65.0%;MgO,0~15.2%;CaO,0~15.2%;SrO,0~15.2%;BaO,0~15.2%;Na2O,0~15.6%;K2O,0~15.6%.通过比较不同组成玻璃的热膨胀系数,讨论该体系玻璃组成与其热膨胀系数之间的关系.研究结果表明:当玻璃中碱金属氧化物的质量分数大于17.8%时,玻璃的热膨胀系数迅速增大;对于具有相同含量的不同碱土金属的玻璃,其热膨胀系数随着碱土金属原子半径的增大而增大;当2种以上不同碱土金属共存时,热膨胀系数呈现明显的混合碱效应;当Li,Na和K 3种碱金属共存时,玻璃的热膨胀系数与组成的关系曲线出现2个极小点,且出现负的混合碱效应.  相似文献   

5.
氨法处理氧化锌矿制取电锌   总被引:4,自引:1,他引:4  
研究了用氯化铵法直接从氧化锌矿提取电锌的新工艺.该工艺采用氯化铵 氨水溶液作浸出剂,氧化锌矿中的锌以锌氨配合物形式进入浸出液,在浸出锌的同时将杂质砷、锑、铁等除去.研究结果表明:氨溶锌浸出率≥93%;浸液中的As和Sb的质量浓度都低于0.25mg/L,Fe的质量浓度低于0.15mg/L,其他杂质质量浓度低;浸出液经锌粉1次净化除杂后进行电积制取电锌.电锌中Zn的质量分数达99.999%,杂质含量极低,其中Fe的质量分数仅为0.00005%;电流效率高达96.35%,直流电耗为2502kW·h;电解废液经补氨后返回浸取.  相似文献   

6.
研究Na OH-Na NO3-Air体系低温碱性熔炼处理废弃电路板多金属粉末的工艺流程,在熔炼过程中对各因素对两性金属的影响进行系统研究,优化得到较为适宜的熔体组成与工艺条件:Na NO3,Na OH和多金属粉末质量比为0.6:2.5:1.0,温度为350℃,空气流量为1.5 L/min,熔炼时间为30 min。研究结果表明:在此条件下Sn,Pb,Al和Sn的转化率分别为100%,83.99%,93.26%和91.97%。针对含两性金属的碱性浸出液,设计Ca(OH)2沉锡和Na2S·9H2O沉铅锌的分离工艺,得到纯度(质量分数)98%以上的Sn O2及Pb S-Zn O混合物。  相似文献   

7.
控制电位氧化法铅阳极泥脱砷   总被引:5,自引:0,他引:5  
采用压缩空气和双氧水作氧化剂,通过控制氢氧化钠体系中的电位来氧化浸出铅阳极泥中的砷。试验中考察电位、NaOH浓度、反应温度、反应时间和液固质量比对脱砷效果的影响,确定碱性浸出过程中预脱砷的最佳工艺条件:NaOH浓度为2 mol/L,温度为80℃,液固质量比为5:1,通入0.2 MPa的压缩空气4 h后用双氧水调节体系的电位至-180 mV,反应时间为2 h。在此条件下,砷的浸出率可达98%以上。碱浸液经冷却过滤掉结晶砷酸钠后,返回浸出过程,砷的浸出率达98%以上,实现碱浸液的循环利用以及砷与其他金属的有效分离。  相似文献   

8.
采用示差扫描量热法(DSC)、X 射线衍射(XRD)、扫描电子显微镜(SEM)等分析方法,研究玻璃组成中碱金属氧化物(Li2O 和Na2O)总量不变时,Li2O 逐渐取代Na2O 对MgO-Al2O3-SiO2 系统微晶玻璃的析晶、热膨胀系数及介电性能的影响.研究结果表明Li2O 和Na2O 总含量(质量分数)为3.6%,其中Li2O 含量为1.8%时,微晶玻璃以α-堇青石为主晶相,热膨胀系数为5.11×10-6 ℃,微波频率下介电常数εr 为5.5,介电损耗tan σ为2.1×10-4;随着Li 对Na 的取代,玻璃的析晶能力增强,初始析晶峰温度从950 ℃降至900 ℃左右,但没有降低第二析晶峰温度;随着Li2O 含量增加,热膨胀系数及介电损耗都出现明显的混合碱效应,曲线呈现先降低后升高的变化趋势;样品的介电常数随Li2O 含量增加单调降低.  相似文献   

9.
氧化锌矿的碱浸出   总被引:2,自引:0,他引:2  
将处理氧化铝矿物的拜耳法移植于氧化锌矿的湿法处理形成"锌拜耳法",用浓碱浸出氧化锌矿,然后降低温度或浓度使锌以氢氧化锌的形式析出,析出母液经浓缩处理后返回浸出矿,研究氧化锌矿的碱浸出过程。研究结果表明:当氢氧化钠浓度为5mol/L,浸出温度为85℃,液固比为10:1,浸出时间为2h时,氧化锌矿中锌的浸出率为77%,铅的浸出率为9%,镉的浸出率为5%。  相似文献   

10.
难选高硅型氧化锌矿机械活化碱法浸出研究   总被引:3,自引:0,他引:3  
针对氧化锌矿综合利用工艺的现状和不足,将处理氧化铝矿物的拜耳法移植于氧化锌矿的湿法处理过程而形成"锌拜耳法",提出氧化锌矿机械活化碱法浸出的新工艺。实验结果表明:当NaOH的用量为理论用量的3.5倍,温度为140℃,浸出时间2 h,液固比为10:1(mL/g)时,锌的浸出率达到95.1%,硅的浸出率为45.5%。氧化锌矿在高温、长时间和强机械活化作用下生成难溶产物Na2ZnSiO4是导致锌浸出率降低的主要原因。  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.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<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   

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