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1.
利用差示量热法(DSC)并结合JMA方程与双峰分离法对过饱和7050铝合金固溶体中第二相粒子的析出动力学进行分析和计算。研究结果发现:GPⅠ区(367±1)K,η′相(507±1)K和η相(524±1)K的激活能分别为(76.5±0.6),(183.6±2.1)和(666.6±16)kJ/mol,常数k0分别为5.48×1010,5.48×1018和3.14×1066/s,同时得到了其相应的组织转变动力学方程。通过计算发现在本实验条件下,7050铝合金固溶淬火后在393 K时效的峰值时间约为280 h,而在453 K时效的峰值时间约为0.5 h。该计算结果与实验结果十分吻合,其对7050铝合金固溶淬火处理后的人工时效过程有一定的指导作用。  相似文献   

2.
本文将液体导热系数公式一之修改为λ_1=Ar_1~(0.667)(B—T)~n使之成为一个简便,正确且适用范围广的公式。并对25种制冷剂进行了计算,确定了待定常数A和B。计算值与文献值相比,最大误差不超过±5%。  相似文献   

3.
根据BES合作组关于R值的最新测量结果,给出了J/ψ,ψ(2S)和ψ(3 770)介子通过虚光子衰变的强子过程的分支比的一个简单计算.首次计算出(J/ψ→γ~*→hadrons)=(12.91±0.14)%和B(ψ(2S)→γ~*→handrons)=(1.68±0.04)%,和B(ψ(3 770)→γ~*→handrons)=(2.11±0.15)×10~(-5),同时也是目前与实验吻合最好的结果.  相似文献   

4.
基于树的无向双环网络G(N;±r,±s)寻径策略   总被引:5,自引:1,他引:4  
提出了新的无向双环网络G(N;±r,±s)的直径求解方法,将其图论模型中的节点进行了重新排列,得到了一种基于树的路由模型,研究了该树型结构中与路由相关的一些性质;给出了计算无向双环嘲络G(N;±r,±s)直径d(N;±r,±s)的显式公式;证明了无向双环网络G(N;±r,±s)的直径等于树高;验证了Boe-sch和Wang等提出的无向双环网络G(N;±r,±s)直径的下界.  相似文献   

5.
用活化法以93Nb(n,2n)92mN反应截面为中子注量标准,然后对172Yb(n,p)172Tm,173Yb(n,P)173Tm,170Yb(n,2n)160Yb,176Yb(n,2n)175Yb的反应截面进行了测量,测得由(14.84±03)MeV中子引起的173Yb(n,p)172Tm的反应截面为(9.4±L0.9)mb,173Yb(n,p)173Tm的反应截面为(3.64±0.2)mb,170Yb(n,2n)169Yb的反应截面为(2 130±81)mb,176Yb(n,2n)175Yb的反应截面分别为(2169±81)mb.把测量的数据和其他作者的数据进行了比较,且利用HFTT程序计算了中子能量在7~18 MeV范围内两个(n,2n)反应和中子能区在5~30 MeV内两个(n,p)反应的截面,给出了这4个核反应的激发函数曲线.  相似文献   

6.
希格斯三重态模型(HTM)预言了类标准模型的中性希格斯玻色子h,还预言了单电荷和双电荷希格斯玻色子(H~±,H~(±±))的存在.主要研究了在高能光子对撞机上的两个三体产生过程:γγ→hH~+H~-和γγ→hH~(++)H~(--).计算结果表明,在合理的参数空间内,两种过程的产生截面分别达到几十fb和一百多fb,分析了主要的标准模型背景并计算了信噪比.由于较低的标准模型背景,在未来的高能直线对撞机上实验中可以通过这些过程探测到带电标量粒子H~±和H~(±±)的信号.  相似文献   

7.
带电基团 A~(±N)(b_1)(…)B(b_2)(…)C(b_3)(…)D(b_4)(…)、A(b_1)(…)B~(±N)(b_2)(…)C(b_3)(…)D(b_4)(…)的诱导电负性指数 X_i(N_A~±)、X__i(A_N~±),可分别通过下式计算:X_i(N_A~±)=X_i(A)±ΔX_(N_A~±)/r_(N_A~±)X_i(A_N~±)=式中,X_i(A)是原子 A 的 Pauling 元素电负性改变值,ΔX_(N_A~±)、ΔX_(N_B~±)等是带电离子的 Pauling 元素电负性改变值,r_(N_A~±),r_(N_B~±)等是离子半径,R_(AB)、R_(BC)等是σ键长。  相似文献   

8.
通过选择合适的计算参数,利用QCD求和规则对基态4+K介子的质量进行了分析和计算.当s0=6.0~6.5 GeV2,1.0 GeV2≤M2≤2.3 GeV2时,计算得到的4+K介子质量的数值结果为(1.831±0.176)GeV,与实验值接近.  相似文献   

9.
以重庆市渝北区、南岸区和渝中区3个主要城区为研究对象,采集夏季PM2.5样品,应用DRI Model 2001A热/光分析仪,采用IMPROVE-TOR方法测定了PM2.5中有机碳(OC)和元素碳(EC)含量,并对3地的OC、EC污染特征进行了评价,探讨了PM2.5中含碳物质的来源。结果表明,南岸区OC、EC质量浓度分别为(5.8±1.5)、(2.5±0.8)μg·m-3,低于渝北区((8.9±3.2)、(4.2±1.6)μg·m-3))和渝中区((8.8±2.2)、(4.6±1.3)μg·m-3),与PM2.5质量浓度的分布一致,表明渝北区和渝中区的含碳污染物的排放可能较为严重。渝北区、南岸区和渝中区的OC与EC均显著正相关,表明三大城区OC和EC可能分别具有相似的一次污染源。排除降雨天和O3浓度较高的晴天,利用m(OC)/m(EC)比值法对渝北区、南岸区、渝中区二次有机碳(SOC)进行估算,SOC质量浓度分别为(2.0±1.8)、(1.0±0.7)、(2.3±2.0)μg·m-3,占OC比例均低于30%。渝中区SOC对OC的贡献率最高,这可能是因为该地区易于形成城市热岛效应,且热量和辐射效应更加明显,有助于SOC的生成。通过计算PM2.5中8个碳组分丰度,初步判断机动车尾气排放可能是三大城区碳质组分的主要来源。  相似文献   

10.
在希格斯三重态模型(HTM)的理论框架下,研究了带电希格斯玻色子对(H~±,H~(±±))与中性的希格斯玻色子h在国际线性对撞机(ILC)上的两个协同产生过程:e-e+→h H~+H~-和e-e+→hH~(++)H~(--),并计算了它们的产生截面,讨论了相关的标准模型背景.结果表明,在合理的参数空间内,这两个过程的产生截面分别达到几个fb和数十fb的量级,在未来的ILC实验上可能通过这些过程探测到HTM中带电标量粒子H~±和H~(±±)的信号.  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.
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   

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.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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