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1.
用微波方法测量半导体非平衡载流子寿命   总被引:2,自引:0,他引:2  
介绍用有哑铃状孔-缝端盖的微波谐振腔测量片状半导体材料非平衡载流子寿命的一种方法.腔体用圆柱TE011模高Q腔,易于更换端盖,可以达到较高的测量精度.实验表明,对同一半导体材料测量得到的有效寿命不因端盖孔-缝的改变而变化,所以可以通过选用孔-缝尺寸不同的端盖,来测量不同电导率的材料,以提高信号幅度,从而提高精度.测量是无接触的,因此无需对样品进行加工.用小的孔-缝端盖还可以用来对半导体材料有效寿命的二维分布进行研究.  相似文献   

2.
对非均匀介质块梳状线谐振腔间的耦合进行了理论分析,提出了一种新型的适于移动通信用的微波带通滤波器结构。这种滤波器是把1/4波长的、相同端短路的梳状线谐振腔安置在一小室中。用矩量法对于4种滤波器的耦合形式进行了数值分析。计算均匀和非均匀情况下,奇偶模激励的(transverseelectro-magnetic,TEM)场得到谐振器的电容参数的理论值,且TEM谐振线之间的耦合系数利用容性参数进行表示。给出了电容耦合系数、电感耦合系数和总的耦合系数的理论值并进行了比较,计算结果显示了理论值和实验值的一致性。  相似文献   

3.
采用耦合模理论及有限元法对TE○11-TE11模式变换器进行了计算机辅助设计,并编写了设计程序.在15GHz波段设计、测试了TE○11-TE11变换器,测试曲线与理论计算曲线有较好的吻合  相似文献   

4.
采用耦合模理论及有限元法对TE11-TE11模式变换器进行了计算机辅助设计,并编写了设计程序,在15GHz波段设计,测试了TE11-TE11变换器,测试曲线与理论计算曲线有较好的吻合。  相似文献   

5.
§1.引言表面复合速度是研究半导体非平衡载流子性质的一个重要参量.借助于表面复合速度的测量可以对半导体表面的基本性质有所了解.而且表面复合速度还直接影响半导体内非平衡载流子的复合,从而影响少数载流子的有效寿命.而半导体两极管的反向饱和电流,击穿电压,三极管的电流放大系数以及噪声水平亦都与表面复合速度有关.测出经各种表面处理后的表面复合速度,并找出减小表面复合速度的途径,对改善器件的性能是很重要的工作.  相似文献   

6.
新型聚乙烯胶粘剂的制备   总被引:1,自引:0,他引:1  
聚乙烯(PE)为非极材料,介电常数小于2.8,用乙烯--醋酸乙烯(EVA)为主剂的热熔胶对粘接非极性高分子材料有较好的性能,本文主要研究了EVA树脂的型号、各组分含量、加热等对EVA热熔胶性能的影响及产品性能的检测。  相似文献   

7.
系统是以新型半导体致冷器件TEC1-12704为工作介质的小型控湿系统,结合数控技术,集报湿、去湿、控湿为一体,可有效对小空间湿度进行测控.  相似文献   

8.
应用周期折射率介质光波导的模场分布函数和特征方程,分析了GaAs/AlGaAs周期折射率光波导中波导的材料参量和结构参量对TE模场分布的影响,并讨论了TE_0表面基摸的形成。  相似文献   

9.
该文研究了圆盘介质谐振器中迴音壁模(WGM)的毫米波特性.在高介电常数圆盘介质谐振器中的迴音壁模非常适用于毫米波段,它所具有的高Q值和大尺寸的特性使得它们宜于加工制造.最后给出了在Ka波段的理论和测量值,两者显示了很好的一致性.  相似文献   

10.
提出用高频C-V法测量半导体异质结中集中分布的界面态的能位位置的方法,并分析了测试温度以及由异质结的能带偏移所引起的载流子积累对测试结果的影响,有这一方法对GaS/GaAs和ZnSe/GaAs两种异质结进行了测试,发现在这两种异质界面上均存在集中分布的界面态,其能级位置分别为Ec-0.41eV,Ec-0.51eV。  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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