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1.
提出了改进前人所提出的测定含CaF_2固态渣导热系数的方法,通过测定有渣壳和无渣壳的铜-氧化铝水冷套管中热流值,即可求出渣壳的导热系数,测定了ANF—6(70%CaF_2—30%Al_2O_3)与L_4(15%CaF_2—50%Al_2O_3—30%CaO—5%MgO)渣的导热系数,其温度范围分别为637~1273℃及760~1188℃,其导热系数均随温度升高而增大,并求出了两种渣导热系数与温度的关系式,在1000℃下L_4渣的导热系数较ANF-6渣少50%,此法简便可靠。  相似文献   

2.
根据电渣重熔工艺要求和渣相平衡的特点,提出电渣重熔用渣化学组成的设计原则。据此原则,研究了CaO-Al_2O_3-SiO_2,三元系中8个共晶组成和二个同分化合物的性质,测定了其电导率和导热系数。根据其性质和电渣重熔实验,从中选出了两个适于电渣重熔用无氟渣系,其共晶组成(wt%):49.5%CaO-43.7%Al_2O_3-6.8%SiO_2和52.0%CaO-41.2%Al_2O_3-6.8%SiO_2。工业实验表明,其冶金性能与ANF-6渣相当,而电耗可降低30%,从根本上消除了氟化物对环境的污染。  相似文献   

3.
本文应用非稳态热线法测定了电渣重熔用高氟二元渣(ANF-6)、低氟四元渣(20CaF_2-50Al_2O_3-20CaO-10MgO)、无氟三元渣(48CaO-48Al_2O_3-4MgO)在600℃和1000℃时的热导率。结果表明,上述三种渣系热导率随温度升高而增加,在600℃时,上述三种渣系的热导率分别为1.191,0.818,0.710W/m·K;在1000℃时,分别为1.483,0.981,0.804W/m·K。在同一温度下,渣系的热导率随渣中CaF_2含量减少及CaO、Al_2O_3含量增加而降低。  相似文献   

4.
根据我国某矿含氟的特点,我们在转动粘度计上进行了含高氟炉渣的粘度和熔化性的研究,我们在含氟化钙量30~50%范围内做了18个配渣的粘度侧定结果发现在一般碱度范围内粘度和熔化性很低而且在碱度CaO/SiO_2=1.8~3.0范围内有一熔化性低区,因此含氟渣应采用高碱度进行操作。 在本研究中还初步测了一下MgO及稀土氧化物的影响  相似文献   

5.
电渣重熔电极熔化过程模型   总被引:2,自引:0,他引:2  
在假设电极为半无限轴的基础上,建立电极微元体热平衡方程式,求出电板表面热损,以及渣通过电极的热损。在此基础上,建立电极熔化端部热平衡式,求得电极熔化速度与电极截面面积,电极端面综合导热系数h_l,高温锥体渣温T_s的关系,最后找出提高电极熔化速度,降低电耗、提高生产率的途径。  相似文献   

6.
本文设计了用失重法测定熔渣挥发率的装置。在 1550℃和氩气氛下,研究了SiO_2MgO、CaO和 Al_2O_3 对 CaF_2 挥发率的影响。结果表明,SiO_2 影响最大,而CaO 影响最小.对含 CaO 和 Al_2O_3 的渣系,水份可提高挥发率。对实用 ANF-6和L_4 渣系的挥发率的测定表明:不含水时ANF-6较L_4 约大38%,掺水后L_4较ANF-6约大57%。  相似文献   

7.
介绍以废物利用和就地取材为目的制成的新型保护渣。找出了保护渣粒度、氧化铁含量与熔点的关系,分析了法中含碳量对导热系数的影响。新型保护渣表面温度比鞍钢二炼钢厂用的保护渣低 120℃,吸收Al_2O_3夹杂的能力高70%,成本降低70元/吨。  相似文献   

8.
丝网回热器中换热性能的优化   总被引:1,自引:0,他引:1  
建立了低温制冷机回热器的非各向同性多孔介质模型,基于可用比热容、轴向导热率、回热效率和综合性能参数等性能指标,以不同目数及丝径、不同物性材料的金属丝网回热器为对象,对回热器的换热性能进行了数值优化研究.结果表明:回热器填料的比热容和密度越大,可用比热容越大,则制冷量越大;可用比热容相同时,热渗透深度大的制冷量反而小;可用比热容随着径向导热率的增加而增大,但制冷量却随之减小;轴径向导热比取0.1时,制冷机的制冷量比回热器按各向同性处理时要高0.5~2.0 W,可见通常模型中不考虑非各向同性因素计算获得的制冷量会偏低;选择导热率相对低的填充材料或通过改变丝网填充方式来降低回热器轴径向导热比,可减小轴向漏热量;通过控制不同目数丝网的填充比例(体积分数),如热端75 0目和冷端25%0目,且冷端采用导热率较低的不锈钢丝网的多段式回热器,可提高回热效率和综合性能参数,从而获得更佳的换热效果.  相似文献   

9.
热物性参数的选取对地源热泵系统的换热效率有明显的影响。根据济南市岩土热物性测试数据,通过分析对比获得岩性和导热系数、比热容等热物性参数的相关关系。分析表明,岩石的导热系数普遍大于第四系松散层,岩石导热系数由高到低为沉积岩、岩浆岩、变质岩,灰岩密度、含水率和孔隙率对热物性参数的影响显著。导热系数随密度增大呈线性增加,随含水率增大呈线性减小,随孔隙率增大呈线性减小。得到以孔隙率为单变量的导热系数和热扩散系数的估算公式。所得结论对济南市浅层地热能调查、评价和开发有指导意义。  相似文献   

10.
从现场焦化炉中截取一段结焦炉管 ,采用热通量法测定了炉管结焦层的导热系数。实验表明 ,当温度为5 0~ 10 0℃时 ,管焦导热系数随温度的升高而迅速降低 ;当温度为 10 0~ 5 5 0℃时 ,随着温度的升高 ,管焦导热系数降低的速度逐渐减缓 ,并最终稳定在 3 .8W/ (m·℃ ) ,实验误差不超过 10 %。对实验数据进行多项式线性回归 ,得到了管焦导热系数随温度变化的回归方程 ,该方程的相对误差低于 4 %。  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.
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   

14.
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   

15.
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   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
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   

20.
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   

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