首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 723 毫秒
1.
在带抗共振环(ARR)的非稳腔Nd:YAG激光器中,将调Q材料Cr^4 :YAG晶体和LiF:F2色心晶体置于ARR中心,获得调Q单脉冲能量分别为86.1mJ。这一输出能量远大于相同实验条件下传统的平-凸非稳腔激光器,理论分析很好地解释了实验结果。  相似文献   

2.
以新型可饱和吸收体 Cr4 ∶ YAG晶体作为调 Q开关 ,在平 -凸非稳腔和平 -平介稳腔中实现被动调 Q运转 .分别获得能量为 70 .5m J和 2 9.7m J,脉宽为 2 3ns和 2 0 ns,能量起伏为 1.9%和 3.8%的调 Q单脉冲输出 .实验结果表明 ,非稳腔有利于输出能量和稳定性的提高 ,理论分析和实验结果相符 .  相似文献   

3.
不同腔型Cr4+:YAG被动调Q激光器   总被引:2,自引:0,他引:2  
以新型可饱和吸收体Cr^4+,YAG晶体作为调Q开关,在平-凸非稳腔和平-平介稳腔中空现被动调Q运转。分别获得能量为70.5mJ和29.7mJ,脉宽为23ns和20ns,能量起伏为1.9%和3.8%的调Q单脉冲输出,实验结果表明,非稳腔有利于输出能量和稳定性的提高,理论分析和结果相符。  相似文献   

4.
理论分析LiF:F~-_2色心晶体的能级结构,计算其激发态吸收的饱和光强,指出基态恢复时间为纳秒量级的LiF实现被动锁模的可能性.利用对撞增强腔Nd:YAG激光器实现LiF晶体的锁模激光输出,获得平均能量为11.8mJ,稳定性大于98%的锁模单脉冲序列.  相似文献   

5.
本文阐述了作者研制的LiF:F_2~-晶体色心调Q的YAG倍频激光器.该激光器输出高重复率、高峰值功率、窄脉宽的脉冲蓝绿激光,适用于机载激光雷达进行大面积、高深度、高精度的海洋探测.文中还介绍了这种激光器输出激光的偏振性、脉冲宽度和能量的稳定性等实验结果.  相似文献   

6.
LiF∶F~-_2色心晶体作为Nd∶YAG激光系统的被动Q开关时,在适当条件下自身亦能产生受激辐射,作者在实验上实现了这种调Q双成份的受激辐射输出,并研究了其各种特性。  相似文献   

7.
LiF:F_2~-色心晶体作为Nd:YAG激光系统的被动Q开关时,在适当条件下自身亦能产生受激辐射,作者在实验上实现了这种调Q双成份的受激辐射输出,并研究了其各种特性.  相似文献   

8.
三种非线性晶体对锁模激光的倍频   总被引:1,自引:0,他引:1  
采用对撞脉冲锁模(CPM),凸-抗共振环(ARR)非稳腔Nd:YAG脉冲激光器为基波光源,其输出参数为波长1.06μm,脉宽10ps,能量20mJ,能量起伏1.2%,对KTP,LBO和BBO这3种非线性晶体进行外腔倍频实验,可分别获得43.80%,33.87%,和26.74%的倍频能量转换,实验结果和理论分析一致。  相似文献   

9.
本文构建了晶体双波长调Q激光腔内倍频的速率方程,通过数值求解,分析了不同腔长条件和倍频耦合条件对双波长脉冲激光时间特性和输出光子数的影响,通过仔细调整腔长和倍频耦合几何因子,理论上获得了均衡的红绿双波长调Q脉冲激光输出.  相似文献   

10.
本文考虑到Nd3+:YAG棒在工作中的热效应,把含热透镜的CPM非稳腔等效为平凸空腔,以此分析CPM非稳腔的结构参数对激光器输出能量、光束远场发散角和抗干扰能力的影响,得出的结论与实验相符。  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.
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   

15.
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   

16.
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   

17.
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   

18.
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   

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.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号