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1.
以SiO2,Al2O3,Y2O3,α-SiC粉体为原料,采用粉末烧结法,于1550℃~1650℃无压烧结2hr.,研制Y-Al-Si-O-C氧碳玻璃.结果表明在1650℃×2h.的烧结条件下,在元素质量百分比为(wt%)Y(15.75)-Al(5.29)-Si(28.82)-O(49.14)-C(1.00)和Y(15.75)-Al(5.29)-Si(29.60)-O(47.36)-C(2.00)的两个成份点可获得氧碳玻璃.  相似文献   

2.
K2O-MgO-SiO2-Al2O3-B2O3-F玻璃陶瓷的烧结析晶   总被引:2,自引:0,他引:2  
利用弯曲试验、X射线衍射分析和扫描电镜等手段,研究了烧结K2O-MgO-SiO2-Al2O3-B2O3-F玻璃陶瓷时烧结温度对材料密度、抗弯强度及析晶性能的影响.研究结果表明:在低温区(900℃)烧结时,玻璃陶瓷析晶少,密度和抗弯强度低;随烧结温度提高,烧结体密度、抗弯强度、析晶率不断提高,在1050℃时均达到最大值(密度约为2 39g/cm3,抗弯强度约为80MPa);温度继续升高到1100℃时,密度、抗弯强度和析晶率都有所降低.  相似文献   

3.
制备了Na_2O-B_2O_3-SiO_2-ZnO-BaO的基质玻璃,该基质玻璃光学性能良好,透光率高,色泽纯净透明。使用基质玻璃与荧光粉共烧结,打磨至1mm可以得到荧光玻璃样品。发现共烧结30min时荧光玻璃有最大的发光强度,烧结时间过长破坏荧光粉的物理结构,烧结时间过短无法获得较好的光学性能。荧光粉含量(质量百分比)为3%时荧光玻璃发射强度最大,荧光粉过少时光转换效率低,荧光粉过多时出现浓度猝灭效应。使用碳粉还原性气氛烧结最大可以获得425%的发光效率提升。  相似文献   

4.
以80V_2O_5-20P_2O_5-xSb_2O_3(x=0,1,3,5mol%)系统玻璃为研究对象,对其进行红外吸收光谱、拉曼光谱、X射线光电子能谱和固体静态核磁共振测试,研究玻璃的网络结构,分析钒磷玻璃中掺杂锑后析晶稳定性提高的机理.结果表明:钒磷系封接玻璃中加入少量的Sb_2O_3后,玻璃网络结构中桥氧比例增加,非桥氧比例下降;同时V~(4+)/V~(5+)增加,这两点原因导致形成V_2O_5晶相所需的V=O键大幅断裂,抑制了该晶相的生成.Sb_2O_3的引入,破坏了网络平衡态的结构,使(VO_3)_n单链逐渐转化为(V_2O_8)n锯齿状链,玻璃结构更加紧密,难以析晶,析晶稳定性提高.  相似文献   

5.
研究高能球磨对Y-Al-Mg-Si-O-N氧氮玻璃原料的非晶化作用。通过X线衍射(XRD)和扫描电子显微镜(SEM)观察,研究球磨转速和球磨时间对Y-Al-Mg-Si-O-N氧氮玻璃原料粉末结构和形貌的影响。研究结果表明:在本实验条件下,随着球磨转速的增加和球磨时间的延长,粉末中的TiO2和MgO首先被非晶化,Y2O3和ZrO2随后也向非晶相转变,SiO2部分被非晶化,Si3N4和Al2O3未发生明显非晶化;在球磨过程中,粉末粒度逐渐变小,由大而薄的片状和纤维状逐步变成细小的球状;粉末的晶粒细化和非晶化促进粉末烧结过程的进行,对于3Y2O3-10Al2O3-3MgO-65SiO2-15Si3N4-2TiO2-2ZrO2体系粉末样品,烧结线收缩率最大达到4.97%,抗弯强度最大为78.1MPa;而对于3Y2O3-10Al2O3-3MgO-50SiO2-30Si3N4-2TiO2-2ZrO2体系粉末样品,烧结线收缩率最大达到7.8%,最大抗弯强度为123.1MPa。  相似文献   

6.
分别以α-Al_2O_3,(α+θ)-Al_2O_3和γ-Al OOH为铝源,采用固相法合成了Mg稳定的β"-Al_2O_3粉体,通过比较各产物中β"相的含量,确定了最佳铝源。以最佳铝源制备的β"-Al_2O_3粉体为原料,进一步通过热压烧结工艺制备了固体电解质陶瓷片,研究了烧结温度对烧结体中的β"相含量、断面形貌、相对致密度以及离子电导率等的影响。借助XRD,TG-DSC,FESEM和EIS对样品进行了测试表征。结果表明:以γ-Al OOH为铝源所制备粉体产物的纯度最高(β"相含量高达99.8%),且能在较宽的温度范围内保持稳定(1 115~1 600℃),而热压烧结温度同时影响陶瓷片中β"相的含量和相对致密度。当烧结压力为30 MPa,烧结温度为1 450℃时,陶瓷片中β"-Al_2O_3的含量高达95%,此时的陶瓷片结构致密、均匀,室温离子电导率约为3.8×10~(-4)S·cm~(-1)。  相似文献   

7.
研究了SiO_2-Al_2O_3-B_2O_3-MgO-MgF_2-K_2O系统金云母(KMg_3[AlSi_3O_(10)]F_2)可切削微晶玻璃制备工艺。通过玻璃的热膨胀曲线、差热分析、梯温析晶的测定,摸索了该系统玻璃的热处理制度:核化温度为600~650℃,晶化温度为1000~1100℃,保温10h。此种玻璃在100℃时体积电阻率为10~(15)Ω·cm,介电损耗为4.1×10~(-3)。用偏光显微镜、透射电子显微镜、X射线衍射探讨了其显微结构。提高晶体的径厚比和结晶率可提高其切削性和电绝缘性。阐述了其可切削性的机理。  相似文献   

8.
以自制LaMgAl11O19(LMA)片状晶和α-Al2O3粉体为原料,采用无压烧结工艺在不同温度(1500℃、1550℃、1600℃、1650℃)下制备了LMA-Al2O3复相陶瓷,研究了烧结温度对LMA-Al2O3复相陶瓷的体积密度和显微形貌的影响。结果表明,LMA-Al2O3复相陶瓷的体积密度随烧结温度的升高呈先降低后升高的变化趋势,当烧结温度为1650℃时可制备获得较为致密的LMA-Al2O3复相陶瓷,添加10wt%的LMA片状晶对LMA-Al2O3复相陶瓷的致密度没有明显影响,但LMA片状晶的加入能够起到使Al2O3晶粒细化的作用。  相似文献   

9.
以Al(NO_3)_3、Y(NO_3)_3的水合物为前驱体,结合溶胶-凝胶法和超临界干燥方式,制备Y掺杂Al_2O_3气凝胶。研究气凝胶经热处理后的比表面积、晶相、微观形貌及气凝胶中Y元素分布形式的变化规律,并分析Y对气凝胶热稳定性的作用机制。结果表明:制备的Y掺杂Al_2O_3气凝胶具有较高的初始比表面积(483 m~2/g),在高温下具有较高的比表面积保留(1 200℃处理后仍有80 m~2/g)。Y元素在Al_2O_3气凝胶中均匀分布,抑制了高温下Al~(3+)的扩散和重排,经1 200~1 300℃热处理后,Y元素由均匀分布转变为非均匀分布,在Al_2O_3颗粒表面生成Y和Al的化合物,能够进一步减少颗粒间的颈部接触,抑制烧结和相变。经1 300℃热处理后,由于Y和Al的化合物本身比表面积较低,气凝胶总的比表面积发生显著下降。  相似文献   

10.
研究一次和二次烧成对CaO-B2O3-SiO2(CBS)微晶玻璃的烧结性能与介电性能的影响。用X线衍射(XRD)、扫描电镜(SEM)等分析探讨二次烧成对CBS微晶玻璃的微观结构与介电性能的关系。结果表明:与一次烧成相比,二次烧成能够促进玻璃体中的小晶粒生长,试样的收缩率和体积密度有所增加,有利于介电常数提高和介质损耗的降低,且体系中没有出现新的晶相;875℃烧结的试样,X/Y轴收缩率均为14.33%,体积密度达到2.46 g/cm3,10MHz介电常数和损耗相应为6.21和3.5×10-3,热膨胀系数为11.86×10-6/℃,抗折强度为157.36MPa。  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.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
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   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
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   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

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