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1.
1,2-二环戊二烯基四甲基二硅烷与丁基锂作用生成[四甲基二硅撑]双(环戊二烯基负离子盐),后者随即与六羰基钨反应形成1,1-[四甲基二硅撑]双[环戊二烯基三羰基钨负离子盐],(Me2SiSiMe2)·[Cp′(CO)3W-]2·2Li+(I).(I)分别与六种卤化物反应,生成在钨原子上引入取代基的产物:(Me2SiSiMe2).[Cp′W(CO)3R]2,(R:Me,C2H5,2;PhCH2,3;CH2COOC2H5,4;CH3CO,5;P3hSn,6).(I)用醋酸处理后,随即分别与CCl4,NBS及I2作用,生成相应的钨卤化物,(Me2SiSiMe2)[Cp′W(CO)3X]2,(X:C1,8;Br,9;I,10),(I)与Fe3+/H3O+作用发生氧化偶联,生成双核W-W键产物(Me2SiSiMe2)[Cp′W(CO)3]2,11.(Cp′=C5H4)  相似文献   

2.
硅基取代环戊二烯基二羰基铁负离子[η^5-RC5H4Fe(CO)2]^-(R=SiMe3,I;Si2Me5,Ⅱ)与铁碘化合物(η^5-C5H5)Fe(CO)2I反应,除得到新的Fe-Fe化合物外,还分离到另两种母体Fe-Fe化合物;桥连化合物(η^5,η^5-C5H4SiM32OSiMe2C5H4)[Fe(CO)2I]2(6)与铁负离子[η^5-C5H5Fe(CO)2]^-(Ⅲ)的反应,仅分离到各  相似文献   

3.
计算机集成制造系统(CIMS)是70年代初国外发展起来的一种制造系统的新模式.本文将系统工程的思想和方法应用于CIMS开发过程,提出了一套由CIMS开发指导思想、CIMS可行性研究、CIMS总体设计、CIMS方案实施及CIMS开发项目管理等组成的完整的CIMS开发方法体系.  相似文献   

4.
本文基于SOIS(单项业务信息系统),从工程应用角度出发论述了开发集成MIS(管理信息系统)的原理、体系结构及工程实现方法,如面向对象的问题求解与程序设计方法、混合编程与变参(实参、形参)策略等.利用文中介绍的方法设计的集成MIS具有与CIMS良好的适应性和较强的工业应用价值.  相似文献   

5.
管理信息系统(MIS,ManagementInformationSystem),发展近三十年来在理论及实际应用方面都已取得令人瞩目的成绩,但是它在支持企业各级管理活动方面提供的功能并不令人满意。因此,MIS的功能还有待加强,MIS的开发工作有待改进。本文对现有MIS存在的主要问题进行了探讨,以增强企业的活力为MIS改进的目标,依据VSM(ViableSystemModel)理论对MIS的改进提出一些设想,并分析了这些设想的可行性。  相似文献   

6.
针对MIS开发过程中某些问题提出一些看法,这些问题均是MIS开发特别值得注意的关键性问题,是MIS开发成败之所在  相似文献   

7.
对计算机在管理领域中的主要应用——管理信息系统(MIS)的开发,提出一种软件部件化技术的方法,并使用此种方法研制出管理信息系统生成系统(MISGS)。它降低了开发难度,提高了开发效率和软件质量,克服了通常MIS开发中遇到的工程量大、周期长、成本高、过程复杂的困难。  相似文献   

8.
为了适应大规模集成器件制作工艺发展的需要,开展了液态金属离子源(LMIS)和聚 焦离子束(NB)的研究。研制成针型、同轴针型与毛细管型的镓与金LMIS,Au-Si、Au- Si-Be与 Pd-Ni-Si-Be-B三种共晶合金型 LMIS:研究了带有控制栅极的 LMIS的控 制性能;编制了计算聚焦离子枪所需的程序;制成三种型式的聚焦离子枪并获得0.1μm 直径的聚焦离子束;制成扫描离子显微镜(SIM);初步开展了刻蚀试验。  相似文献   

9.
针对MIS开发过程中某些问题提出了一些看法,这些问题的MIS开发特别值得注意的关键性问题,是MIS开发成败之所在。  相似文献   

10.
MIS(管理信息系统)软件是社会需求最大的一类应用软件,因此,怎样快速开发优质的此类管理软件,已成为软件工作人员面临的迫切问题.由于计算机第四代语言(4GL)所遵循的原则是:在最短的时间内,用最少的人力开发出功能最强、错误最少、最易维护的系统,所以第...  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.
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   

20.
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   

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