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1.
引入了F-倾斜对与F-W-倾斜对的概念,它是对倾斜对和W-倾斜对概念的推广,给出了F-W-倾斜对存在的条件,并研究了F-W-倾斜对与W-倾斜对的关系.  相似文献   

2.
n-Frobenius 对     
引入了左(右)n-Frobenius对和特殊的左(右)n-Frobenius对的定义,研究了它们的性质,讨论了左(右)n-Frobenius对和右(左)n-余挠对之间的关系,给出了特殊的左(右)n-Frobenius对的等价刻画。最后给出了特殊的左(右)n-Frobenius对的一些应用,以及左完全的QF环的等价刻画。  相似文献   

3.
对甲氧基肉桂酸对酪氨酸酶的抑制机理   总被引:2,自引:0,他引:2  
以L-酪氨酸和L-多巴为底物研究了对甲氧基肉桂酸对酪氨酸酶的抑制能力,结果表明,对甲氧基肉桂酸对酪氨酸酶催化单酚底物L-酪氨酸有较强的抑制作用,但对酪氨酸酶催化二酚底物L-多巴没有抑制作用.文中采用荧光光谱以及分子对接手段探讨了对甲氧基肉桂酸对酪氨酸酶的抑制机理,认为对甲氧基肉桂酸对酪氨酸酶的荧光光谱属于静态猝灭,在酪氨酸酶活性中心与酪氨酸酶结合形成复合物,以氢键和疏水作用力稳定结构;在酪氨酸酶活性中心,对甲氧基肉桂酸占据了单酚底物的空间位置,对酪氨酸酶的抑制应该是一种竞争性抑制.  相似文献   

4.
报道了对氰基苯酚对蘑菇酪氨酸酶单酚酶和二酚酶活力的抑制效应.结果表明,对氰基苯酚对酪氨酸酶活性的抑制作用表现为可逆抑制作用,对酪氨酸酶的单酚酶的效应主要表现于迟滞时间有明显的延长,对稳态酶活力有显著抑制作用.0.50mmol/L对氰基苯酚使得单酚酶的迟滞时间从18s延长到80s,增大4.4倍,稳态酶活力下降80%.对氰基苯酚对二酚酶的抑制作用显示浓度关系,测定导致酶活力下降50%的抑制剂浓度(IC50)为0.80mmol/L,其抑制作用为竞争性类型,抑制常数KI为0.31mmol/L.通过研究对氰基苯酚对酪氨酸酶的抑制作用机理,试图寻找新型的有增白作用的化妆品添加剂.  相似文献   

5.
推广了特征值与特征向量的概念,并讨论了伪特征值对与伪特征向量对的一些性质。  相似文献   

6.
对醛基苯甲酸对蘑菇酪氨酸酶的抑制作用   总被引:1,自引:0,他引:1  
酪氨酸酶是一种同时具有单酚酶和二酚酶活力的酶.对醛基苯甲酸(ABA)对蘑菇酪氨酸酶活力的影响研究结果表明:ABA只对蘑菇酪氨酸酶的二酚酶活性有抑制作用.而对单酚酶没抑制作用.ABA对二酚酶的抑制作用显示浓度关系,测定导致酶活力下降50%的抑制剂浓度(IC50)为0.98mmol/L.ABA对二酚酶的效应为可逆的非竞争性的抑制.抑制常数K1为0.94mmol/L.本得到的结果与苯甲酸和苯甲醛的效应进行了比较.  相似文献   

7.
在亚硫酸钠溶液中加入微量的对-苯二胺,可以改善它的稳定性。考察了不同用量的对-苯二胺在不同温度下对溶液稳定性的影响。实验证明,加入微量对-苯二胺对定性和定量实验没有不良影响,而且还能降低实验误差。在亚硫酸钠溶液和亚硫酸氢钠溶液中加入微量对-苯二胺均能增加抗氧化作用。  相似文献   

8.
我公司1#,2#焦炉自开工以来,循环水泵高压电机、低温水泵电机,制冷泵电机轴承烦繁损坏,经检查为电机与设备对中偏差遣枣,遂对各个设备遥一重新对中找正,现各设备运行平稳。由此可见,旋转设备的许多故障与设备的部队中有关,设备的不对中会使设备产生振动、轴承损坏、联轴器损坏等缺陷。  相似文献   

9.
讨论了对力项位相的BCS定义和C-S定义间的关系;证明了在ω=0的情况下,两种不同位相定义的对力哈密顿量是等价的;而在ω≠0的情况下,两者则是完全不相同的。  相似文献   

10.
研究了在谱自仿测度中的重要概念谱对和和谐对的刻画.最近,Dorin.Ervin.Dutkay and P.E.T.Jorgensen在Quasiperiodic spectra and orthogonality for iterated function system measures一文中建立了一个一维中谱对和和谐对的刻画,并且得到这种谱集的谱只有有限多个.本文将这一结论推广到了n维,也得到这种谱集的谱只有有限多个.  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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